Title of Invention	COOLING WATER SUPPLY DEVICE
Abstract	To provide a cooling water supply device which effectively makes use of a dead space defined between a radiator and an engine while ensuring a space around a cylinder head. [Means for Resolution] A cooling water supply device 120 includes a crankcase 54 which supports a crankshaft 58 rotatably driven by the engine 50, a cooling water pump 125 which is driven by a driving force from the crankshaft 58 and discharges the cooling water by pressurizing the cooling water, a radiator 129 which is arranged on a side portion of the crankcase 54 and radiates heat of the cooling water, and a thermostat 130 which is arranged in a path between the radiator 129 and the cooling water pump 125 and allows the cooling water to flow into the radiator 129 when a temperature of the cooling water is higher than a given value and allows the cooling water to bypass the radiator 129 when the temperature of the cooling water is equal to or lower than the given value. In such a cooling water supply device 120, the cooling water pump 125 is arranged on a side surface of the crankcase 54, and the thermostat 130 is arranged in a space defined between the cooling water pump 125 and the radiator 129. [Selected drawing] Fig. 10

Title of Invention

COOLING WATER SUPPLY DEVICE

Abstract

To provide a cooling water supply device which effectively makes use of a dead space defined between a radiator and an engine while ensuring a space around a cylinder head. [Means for Resolution] A cooling water supply device 120 includes a crankcase 54 which supports a crankshaft 58 rotatably driven by the engine 50, a cooling water pump 125 which is driven by a driving force from the crankshaft 58 and discharges the cooling water by pressurizing the cooling water, a radiator 129 which is arranged on a side portion of the crankcase 54 and radiates heat of the cooling water, and a thermostat 130 which is arranged in a path between the radiator 129 and the cooling water pump 125 and allows the cooling water to flow into the radiator 129 when a temperature of the cooling water is higher than a given value and allows the cooling water to bypass the radiator 129 when the temperature of the cooling water is equal to or lower than the given value. In such a cooling water supply device 120, the cooling water pump 125 is arranged on a side surface of the crankcase 54, and the thermostat 130 is arranged in a space defined between the cooling water pump 125 and the radiator 129. [Selected drawing] Fig. 10

Full Text	[Designation of Document] Specification [Title of the Invention] COOLING WATER SUPPLY DEVICE [Technical Field] [0001] The present invention relates to a cooling water supply device which supplies cooling water to a water jacket formed in the inside of a cylinder head so as to cool the cylinder head. [Background Art] [0002] In efficiently generating power using an engine, there may be a case that it is preferable to set temperatures of a cylinder head and a cylinder block respectively. In this case, there has been known the structure in which a radiator is arranged on a side surface of a crankcase and, at the same time, a thermostat is arranged on a side of the cylinder head (see patent document 1, for example). [0003] [Patent Document 1] JP-A-2003-172143 [Disclosure of the Invention] [Problems that the Invention is to Solve] [0004] However, according to such a constitution, there lies a long distance between the cylinder head and the radiator and hence, a cooling water passage (cooling water pipe) is elongated. Further, the radiator covers only an AC generator (ACG) in a side view and is not configured to cover other parts. Accordingly, there has been a drawback that a dead space is formed between the radiator and the engine. Further, since the thermostat is arranged on the cylinder head, there has been also a drawback that a periphery of a cylinder on which a large number of parts are arranged becomes further large-sized. [0005] The present invention has been made under such circumstances and it is an object of the present invention to provide a cooling water supply device which can effectively make use of a dead space between a radiator and an engine while ensuring a space around a cylinder head. [Means for solving the problem] [0006] To overcome the above-mentioned drawbacks, a cooling water supply device according to a first aspect of the present invention supplies cooling water for cooling an engine into a water jacket formed in the inside of the engine and includes a crankcase which supports a crankshaft rotatably driven by the engine, a cooling water pump which is driven by a driving force from the crankshaft and discharges the cooling water by pressurizing the cooling water, a radiator which is arranged on a side portion of the crankcase and radiates heat of the cooling water, and a thermostat which is arranged in a path between the radiator and the cooling water pump and allows the cooling water to flow into the radiator when a temperature of the cooling water is greater than a given value and allows the cooling water to bypass the radiator when the temperature of the cooling water is equal to or lower than the given value, wherein the cooling water pump is arranged on a side surface of the crankcase, and the thermostat is arranged in a space defined between the cooling water pump and the radiator. [0007] In the cooling water supply device according to the first aspect of the present invention, it is preferable that a radiator fan which cools the radiator is provided to an end portion of the crankshaft, and the thermostat is arranged in front of and below the radiator fan in a side view. [0008] A cooling water supply device according to a second aspect of the present invention supplies cooling water into a water jacket formed in the inside of the engine and includes a radiator which is arranged on a side portion of the engine and radiates heat of the cooling water, a radiator cover which covers the radiator, a cooling water pump which discharges the cooling water by pressurizing the cooling water, a thermostat which is arranged in a path between the radiator and the cooling water pump and allows the cooling water to flow into the radiator when a temperature of the cooling water is greater than a given value and allows the cooling water to bypass the radiator when the temperature of the cooling water is equal to or lower than the given value, and a thermostat cover which covers the thermostat; wherein a cooling water pipe joint to which a bypass passage allowing the cooling water which bypasses the radiator to flow therein is connected is formed on the thermostat cover, andthe cooling water pipe joint is overlapped to at least a portion of the radiator cover in a side view. [0009] Here, it is preferable that the radiator and the thermostat cover are arranged in a state that the radiator and at least a portion of the thermostat cover are overlapped to each other, and a discharge hole which discharges the cooling water is formed at a portion where the radiator is overlapped to the thermostat cover in a side view, and the cooling water supply device includes a connecting pipe which connects the discharge hole and the inside of the thermostat cover. [0010] In the cooling water supply devices according to the first and second aspects of the present invention, it is preferable that the thermostat has the inside thereof partitioned by a valve element provided inside thereof into a first thermostat chamber and a second thermostat chamber in a state that the first thermostat chamber and the second thermostat chamber become communicable with each other or non-communicable from each other and includes a first introducing portion and a second introducing portion which are respectively connected to the first thermostat chamber and the second thermostat chamber, and the first and second introducing portions are positioned at a height equal to or higher than upper ends of the first and second thermostat chambers in the vertical direction. [Advantage of the Invention] [0011] In the cooling water supply device according to the first aspect of the present invention having the above-mentioned constitution, since the thermostat is arranged between the radiator and the cooling water pump arranged in the crankcase, it is possible to effectively make use of a dead space defined between the radiator and the crankcase. Further, the thermostat constitutes a portion of a cooling water flow passage which allows the cooling water to flow into the cooling pump, it is possible to shorten the cooling water pipe in which the cooling water flows. Here, by arranging the thermostat in front of and below the radiator fan, it is possible to further make use of the dead space. [0012] In the cooling water supply device according to the second aspect of the present invention having the above-mentioned constitution, it is possible to protect the cooling pipe joint formed on the thermostat cover in a projecting manner with the radiator cover. Here, by forming the discharging hole at the position where the radiator and the thermostat cover are overlapped to each other, it is possible to shorten the distance between the radiator and the thermostat and, at the same time, it is possible to protect the connecting pipe with the radiator cover. [0013] Here, by partitioning the inside of the thermostat using the valve element in a state that the first thermostat chamber and the second thermostat chamber become communicable with each other or non-communicable from each other and allowing the first introducing portion and the second introducing portion to be communicated with the first thermostat chamber and the second thermostat chamber which are portioned by the valve element, and, further, by constituting the first and second introducing portions that the first and second introducing portions are positioned at the height equal to or higher than upper ends of the first and second thermostat chambers in the vertical direction, it is possible to make air hardly stay in the inside of the first and second thermostat chambers without providing the particular structure for bleeding the air which stays in the inside of the first and second thermostat chambers. [Best Mode for Carrying out the Invention] [0014] Hereinafter, the preferred mode for carrying out the present invention is explained based on the attached drawings. Here, a scooter-type vehicle 1 on which a cooling water supply device according to the present invention is mounted is explained in conjunction with Fig. 1. The scooter-type vehicle 1 includes a vehicle body frame 2. The vehicle body frame 2 is constituted of a head pipe 3 which is arranged in front portion of the vehicle body frame 2 and extends in the vertical direction, a down frame 4 which extends below from the head pipe 3, a pair of left and right side frames 5 which extend downwardly, rearwardly and, thereafter, in the rearward upper oblique direction from a substantially center portion of the down frame 4, and an arcuate curve frame 7 which is mounted on the side frames 5 by way of a side plate 6. [0015] A steering shaft not shown in the drawings is mounted on the head pipe 3 in a rotatable manner and a front fork 8 is mounted on a lower end of the steering shaft. A front wheel 9 is supported on a lower end of the front fork 8. On the other hand, a handle post 10 is mounted on an upper end of the steering shaft. Further, a handle 11 is mounted on an upper end of the handle post 10, and the front wheel 9 can be steered by manipulating the handle 11. Further, an upper stay 12 and a lower stay 13 are mounted on the head pipe 3 in a state that the upper stay 12 and the lower stay 13 extend frontwardly from the head pipe 3. A front basket 14 is mounted on front ends of the upper and lower stays 12, 13. [0016] A fuel tank 15 is mounted on lower portions of a pair of side frames 5 and between a pair of the side frames 5. A link mounting portion 48 which is formed on a front end of a power unit 16 is mounted on a rear end of the curved frame 7 which is positioned behind the fuel tank 15 in a vertically swingable manner and, at the same time, a rear end of the power unit 16 is mounted on a rear end of either one of the side frames 5 by way of a rear cushion unit 17. Here, a fuel pump 18 which includes a tumbling sensor therein is mounted on the fuel tank 15, and the fuel can be supplied to the fuel tank 15 from a fuel supply port (cap) 19 which is mounted on an upper portion of the fuel tank 15. Further, the power unit 16 is constituted of an engine 50, a transmission 90, a throttle body 21, an air cleaner 22, an exhaust pipe 23 which is extended rearwardly from the engine 50, and a muffler 24 which is connected to a rear end of the exhaust pipe 23. A rear wheel 25 is mounted on the rear end of the power unit 16. The rear wheel 25 is driven by the power unit 16 and hence, the scooter-type vehicle 1 obtains power and can travel. [0017] A luggage box 26 and a grab rail 20 are mounted on the rear portion of the side frame 5. The luggage box 26 has a front portion thereof supported on a front side cross pipe 27 which is mounted on the side frame 5 by way of a front side plate 28, and has a rear portion thereof supported on a gate-type frame 29 mounted on the side frame 5. Further, the grab rail 20 is supported on a rear portion stay 3 0 which extends upwardly from the side frame 5. Here, helmets 31, 32 are shown in a state that the helmets 31,32 are accommodated in the inside of the luggage box 26. Further, a rear portion accommodating box 33 is mounted on a rear portion of the grab rail 20. [0018] In the scooter-type vehicle 1 having the above-mentioned constitution, a front upper portion of the vehicle body is covered with a front cover 34 and left and right front side covers 35 are mounted on lower portions of side portions of the front cover 34 . A turn signal lamp not shown in the drawings is mounted on the front side cover 35. A front inner cover 36 is mounted on the rear portion of the front cover 34, and side portions of step floors 37 on which a driver and a pillion passenger place their foots are covered with side covers and under covers 38. Further, a seat 39 is mounted on the luggage box 26, and a lower periphery of the seat 39 is covered with a body cover and a body side cover 40. Still further, a handle cover 42 which covers a handle 11 is mounted above the front cover 34, and a head lamp 43 is mounted on the handle cover 42. Further, a front fender 44 is mounted in a state that the front fender 44 covers the front wheel 9 from above and a rear fender 45 is mounted in a state that the rear fender 45 covers the rear wheel 25 from above. [0019] Further, a tail lamp 46 is arranged below the grab rail 20 and a buttery 41 is accommodated between the front cover 34 and the front inner cover 36. [0020] Next, hereinafter, the details of the power unit 16 are explained in conjunction with Fig. 2 to Fig. 5. Here, in this embodiment, an arrow F shown in Fig. 2 indicates the frontward direction, and an arrow U shown in Fig. 3 indicates the upward direction. An engine 50 which forms the power unit 16 is constituted of a cylinder head cover 51, a cylinder head 52, a cylinder block 53, and a crankcase 54. A cylinder sleeve 55 is fixed in a cylinder block 53. A cylinder chamber 55a is formed in a cylinder sleeve 55 in a state that the cylinder chamber 55a is surrounded by the cylinder sleeve 55, and a piston 56 is disposed in the cylinder chamber 55a in a vertically slidable manner. The piston 56 is connected to a crankshaft 58 which is rotatably supported in the inside of the crankcase 54 by way of a connecting rod 57. With a combustion chamber 59 which is defined by the cylinder block 53 (cylinder sleeve 55), the cylinder head 52 and the piston 56, an intake port 60 and an exhaust port 61 are communicated by way of an intake opening and an exhaust opening. Further, with respect to a mushroom-shaped intake valve 62 and a mushroom-shaped exhaust valve 63, one ends thereof are mounted on valve shafts and are supported by retainers, while another ends thereof are biased by valve springs 64, 65 which are supported on the cylinder head 52 in the direction that the intake valve 62 and the exhaust valve 63 normally close the intake opening and the exhaust opening. [0021] Still further, a cam shaft 66 which performs the open/close operation of the intake valve 62 and the exhaust valve 63 is rotatably arranged in the cylinder head 52. The cam shaft 66 includes a cam driven sprocket 67 and the crankshaft 58. A timing chain 69 is wound around a cam driven sprocket 67 which is mounted on the cam shaft 66 and a cam drive sprocket 68 which is mounted on the crankshaft 58. Due to such a constitution, the cam shaft 66 is rotated in conformity with the rotation of the crankshaft 58 and cams 70, 71 which are formed on the cam shaft 66 pushes down the intake valve 62 and the exhaust valve 63 by way of rocker arms 72, 73 whereby the intake opening and the exhaust opening are opened and closed. Further, an injector 74 is mounted in the intake port 60 and hence, the fuel is atomized in a form of fine particles and is jetted into the intake port 60 from the injector 74. Still Further, an ignition plug 75 is mounted on the cylinder head 52. [0022] Here, a cam chain tensioner 84 which adjusts the timing of the opening/closing of the intake valve 62 and the exhaust valve 63 using the cams 70, 71 by adjusting a tension of the timing chain 69 is mounted on a side portion of the cylinder block 53. [0023] In the inside of the engine 50 having such a constitution, the air-fuel mixture of air which is cleaned by the air cleaner 22 and fuel which is jetted from the injector 74 is supplied to the combustion chamber 59 from the intake port 60, and the air-fuel mixture is ignited by the ignition plug 75 and burnt after being compressed by the piston 56 and hence, the energy which rotates the crankshaft 58 by way of the piston 56 is generated. Thereafter, the exhaust gas is discharged to the outside from the exhaust port 61. [0024] The crankshaft 58 is constituted of a right crankshaft two-split body 58a and a left crankshaft two-split body 58b. The connecting rod 57 is connected to the crankshaft 58 by way of a crank pin 76 which is arranged to join both of the crankshaft two-split bodies 58a, 58b. Further, the crankcase 54 which accommodates the crankshaft 58 is constituted of a right case two-split body 54a and a left case two-split body 54b. One end of the crankshaft 58 (a journal portion of the right crankshaft two-split body 58a) is supported on the right case two-split body 54a by way of a bearing 77, while another end of the crankshaft 58(a journal portion of the left crankshaft two-split body 58b) is supported on the left case two-split body 54b by way of a bearing 78. Further, an ACG 79 and a radiator fan 85 are arranged at a distal end portion of the journal portion of the right crankshaft two-split body 58a. [0025] The left side portion of the left case two-split body 54b extends rearwardly and constitutes a portion of a transmission case 80, and a transmission 90 is accommodated in a transmission chamber 82 which is surrounded by a transmission cover 81 mounted on a left side surface of the left case two-split body 54b. The transmission 90 is constituted of a drive pulley 91 which is mounted on a distal end portion of a journal portion of the left crankshaft two-split body 58b which extends in the inside of the transmission chamber 82 and is integrally rotated with the left crankshaft two-split body 58b, a counter shaft 92 which is positioned behind the transmission chamber 80 f extends in parallel to the crankshaft 58 and is mounted in a rotatable manner, a driven pulley 93 which is mounted on a substantially center portion of the counter shaft 92 in a relatively rotatable manner with respect to the counter shaft 92, a clutch 94 which is mounted on a left end of the counter shaft 92 and performs the engagement and the disengagement of the driven pulley 93 and the counter shaft 92, and a transmission belt not shown in the drawings which is wound around the drive pulley 91 and the driven pulley 93 and transmits the rotation of the drive pulley 91 to the driven pulley 93. [0026] The drive pulley 91 is constituted of a fixed pulley two-split body 91a which is mounted on the crankshaft 58 in an integrally rotatable manner and a movable pulley two-split body 91b which is movable in the axial direction relative to the fixed pulley two-split body 91a and is integrally rotatable with the crankshaft 58. The transmission belt is sandwiched between the fixed pulley two-split body 91a and the movable pulley two-split body 91b. On the other hand, the driven pulley 93 is constituted of a fixed pulley two-split body 93a which is mounted on the counter shaft 92 in a relatively rotatable manner and a movable pulley two-split body 93b which is movable in the axial direction relative to the fixed pulley two-split body 93a and is rotatable relative to the to the counter shaft 92. The transmission belt is sandwiched between the fixed pulley two-split body 93a and the movable pulley two-split body 93b. Accordingly, by variably setting pulley widths of the drive pulley 91 and the driven pulley 93, winding radii of the transmission belt to the both pulleys 91, 93 can be continuously changed whereby a transmission ratio can be controlled variably (continuously). [0027] In parallel to the counter shaft 92, an idling shaft 95 and a rear wheel shaft 96 which mounts a rear wheel 25 thereon are provided in a rotatable manner. A rotational driving force of the counter shaft 92 is transmitted to the rear wheel 25 by way of the counter shaft 92, the idling shaft 95 and a gear train which is mounted on the rear wheel shaft 96. In this manner, an output of the engine 50 is transmitted to the crankshaft 58. Then, after receiving the change-gear operation of the transmission 90, the rotational drive force is transmitted to the rear wheel 25. [0028] Here, when the above-mentioned power unit 16 is operated, the respective parts generate heat and hence, it is necessary to cool the respective parts. Accordingly, with respect to the cylinder head 52, a water jacket 122 is formed on the cylinder head 52 and the cylinder head 52 is cooled by the cooling water which flows in the inside of the water jacket 122. With respect to the cylinder block 53, a plurality of cooling fins 86 which project outwardly are formed on a side portion of the cylinder block 53. The cooling fins 86 radiate heat generated in the cylinder block 53. Further, a cooling wind introducing passage 83 which takes outside air in the inside of the transmission chamber 82 is arranged in front of the transmission case 80 in a state that the cooling wind introducing passage 83 extends frontwardly. Due to such a constitution/ the transmission case 80 can be cooled. [0029] Hereinafter, the cooling water supply device 120 which is used in the scooter-type vehicle 1 having the above-mentioned constitution is explained using also Fig. 6 to Fig. 10. The cooling water supply device 120 supplies the cooling water into the inside of a water jacket 122 which is mounted on the cylinder head 52 so as to cool the cylinder head 52. The cooling water supply device 120 is constituted of a cooling water pump 125 which pressurizes and discharges the cooling water, a radiator 129 which collects the cooling water used for cooling the water jacket 122 and irradiates the heat of the cooling water, and a thermostat 130 which, when a temperature of the cooling water indicates a value below given value, returns the cooling water to the water jacket 122 without performing the heat radiation of the cooling water using the radiator 129. [0030] The cooling water pump 125 is mounted on one end of a pump shaft 132 which extends substantially in parallel to the right crankshaft two-split body 58a* The cooling water pump 125 includes an impeller 131 which pressurizes the cooling water when the impeller 131 is rotated by the pump shaft 132. A pump driven sprocket 133 is mounted on another end of the pump shaft 132. Further, between the pump shaft 132 and the right crankshaft two-split body 58a, a pump idling shaft 134 which extends substantially in parallel to these shafts 58a and 132 is provided. On the pump idling shaft 134, a pump driven gear 136 which is meshed with a pump drive gear 135 joined to the right crankshaft two-split body 58a is mounted. Further, a pump drive sprocket 137 is mounted on the pump idling shaft 134 in a juxtaposed manner. Further, a pump chain 138 is wound around a pump drive sprocket wheel 137 and a pump driven sprocket wheel 133. Due to such a constitution, the rotation of the right crankshaft two-split body 5 8a which is generated by driving the engine 50 is transmitted to the pump idling shaft 134 by way of the pump drive gear 135 and the pump driven gear 136. The rotation of the pump idling shaft 134 is transmitted to the pump driven sprocket wheel 133 from the pump drive sprocket 137 by way of the pump chain 138 and the pump shaft 132 is rotated. Accordingly, the cooling water is pressurized and is discharged from the discharge opening 126 of the cooling water pump 125. In front of the combustion chamber 59 formed in the cylinder head 52, the water jacket 122 which is a space formed so as to cover the combustion chamber 59 is provided. Further, the cylinder head 52 includes a cooling water discharge portion 121 on an upper side portion of the water jacket 122. In the cooling water discharge portion 121, a cooling water discharging passage 121a which is communicated with the outside and the water jacket 122 and discharges cooling water to the outside is formed. Further, the cylinder head 52 includes a cooling water introducing space 123 which is formed below and behind the water jacket 122 and also adjacent to the water jacket 122. The cooling water introducing space 123 opens at a rear side surface of the a lower portion of the cylinder head 52 and is communicated with the water jacket 122. [0032] On the other hand, a cooling water introducing portion 128 which projects downwardly is formed on a lower side surface of a front portion of the cylinder block 53. In the cooling water introducing portion 128, a first passage 140a which has an introducing opening 128a which opens sideward and extends sideward and a second passage 140b which is communicated with the first passage 140a and extends frontward are formed (hereinafter, the first and second passages 140a, 140b are referred to as "cooling water introducing passage 140" as a general term). The second passage 140b includes a discharge opening 128b which opens at a front end surface of the cylinder block 53. When the cylinder head 52 is mounted on the cylinder block 53, an opening portion (discharge opening 128b) of the second passage 140b is communicated with the opening portion of the cooling water introducing space 123 of the cylinder head 52 so that the cooling water introducing passage 140 is communicated with the water jacket 122. Further, a discharge opening 126 of the cooling water pump 125 and the cooling water introducing portion 128 formed in the cylinder block 53 are arranged close to each other and these discharge opening 126 and cooling water introducing portion 128 are connected by a cooling water supply pipe 127. [0033] The thermostat 130 includes a first introducing portion 141 and a second introducing portion 142. The thermostat 130 is configured such that when a temperature of the cooling water which flows in the thermostat 130 from the first and the second introducing portions 141, 142 is equal to or below a given temperature, the second introducing portion 142 is closed and the cooling water is discharged to a discharge portion 143 from the first introducing portion 141, while when the temperature of the cooling water is higher than the given temperature, the first introducing portion 141 is closed and the cooling water is discharged to the discharging portion 143 from the second introducing portion 142. Further, a valve element 154 which has an axis thereof inclined frontward in a side view is provided to the inside of the thermostat 130, wherein the inside of the thermostat 130 is partitioned to a first thermostat chamber SI which is communicated with the first introducing portion 141 and a second thermostat chamber S2 which is communicated with the second introducing portion 142 by the valve element 154. [0034] To the cooling water discharging portion 121 formed on the cylinder head 52, a first cooling water pipe 144 is connected. The first cooling water pipe 144 is bifurcated to a second cooling water pipe 146a and a third cooling water pipe 146b at a branched portion 145. The second cooling water pipe 146a is connected to a suction hole 147 of the radiator 129, while the third cooling water pipe 146b is connected to the first introducing portion 141 of the thermostat 130. on the other hand, the second introducing portion 142 of the thermostat 130 is connected to a discharging hole 148 of the radiator 129 arranged in the vicinity of the second introducing portion 142 by way of a connecting pipe 149 having rigidity. At the branched potion 145, a positioning portion 145a which is used for performing the positioning when the first to third cooling water pipes 144, 146a, 146b are mounted is formed. [0035] Here, a housing (thermostat cover 130a) which accommodates the thermostat 130 therein is integrally formed with a housing which accommodates the cooling water pump 125 and hence, the discharge portion 143 of the thermostat 130 and a suction opening 150 of the cooling water pump 125 are directly connected with each other. Accordingly, the thermostat 130 constitutes a portion of a cooling water passage which supplies the cooling water to the suction opening 150 of the cooling water pump 125. By shortening a flow passage through which the cooling water flows, it is possible to allow the thermostat 130 to have a compact shape as a whole. Further, by providing the constitution which enables the connection of the radiator 129 and the thermostat 130 using the connection pipe 149, it is possible to enhance the assembling property of the power unit 16. [0036] According to the cooling water supply device 120 having such a constitution, the cooling water discharged from the cooling water pump 125 flows in the water jacket 122 through the cooling water introducing passage 140 of the cooling water introducing portion 128 formed on the cylinder block 53. Further, the cooling water is discharged to the outside from the cooling water discharge portion 121 after cooling the cylinder head 52 . Although the discharged cooling water flows in the suction hole 147 of the radiator 129 or the first introducing portion 141 of the thermostat 130, when the temperature of the cooling water is equal to or below a given value, since the second introducing portion 142 is closed by the thermostat 130, the cooling water returns to the cooling water pump 125 without passing through the radiator 129, while the temperature of the cooling water is higher than the given value, the first introducing portion 141 is closed by the thermostat 130 and hence, the cooling water returns to the cooling water pump 125 from the second introducing portion 142 after radiating heat through the radiator 129 and circulates. [0037] In this manner, the intake opening for the cooling water (cooling water introducing portion 128) for cooling the cylinder head 52 is not formed in the cylinder head 52 but is formed in the cylinder block 53 and hence, the degree of freedom in designing the surrounding of the cylinder head 52 can be enhanced and, at the same time, it is possible to effectively make use of a dead space around the cylinder block 53. Here, as can be clearly understood from Fig. 4 or the like, the cooling water introducing portion 128 is mounted on a front end portion of the cylinder block 53, that is, is arranged in the vicinity of the cylinder head 52 and hence, the cooling water introducing passage 140 can be shortened as a whole whereby the cooling water introducing passage 140 can be light-weighted and, at the same time, a manufacturing cost can be reduced. Further, the forming of the cooling water introducing passage 140 in the cylinder block 53 can be facilitated. [0038] Here, such a cooling water supply device 120 is arranged in a concentrated manner on a right side portion of the power unit 16, wherein the radiator 129 is accommodated in the radiator cover 152 and the radiator outer cover 153 which are mounted on a right end portion of the right crankcase two-split body 54a. Here, the radiator 129 is arranged outside and remoter from the vehicle body than the radiator fan 85, and the thermostat 130 is arranged in front of and below the radiator 129 in a side view and, further, is arranged such that the cooling water pump 125, the thermostat 130 and a portion of the radiator 129 (radiator cover 152) are overlapped to each other in a side view. [0039] Accordingly, the cooling water pump 125 can be arranged on the side portion of the crank case 54 and at a position close to the crank shaft 58 and hence, a driving force of the crank shaft 58 can be easily utilized. Further, the cooling water pump 125 and the thermostat 13 0 can be arranged in a space defined between the radiator 129(radiator cover 152) and the cylinder block 53 or the crank case 54 and hence, it is possible to effectively make use of a dead space and to make the whole structure compact. In the same manner, by arranging the thermostat 130 (thermostat caver 130a) between the cylinder block 53 and the link mounting portion 48, it is possible to enhance the space utilization efficiency. Further, by arranging the thermostat 130 below the radiator 129, it is possible to make air (bubbles) hardly stay in the thermostat 130. Still further, a second thermostat chamber S2 which is communicated with the first introducing portion 142 is arranged below a line LI which extends in the horizontal direction from an upper end of the discharging opening 148. Accordingly, it is possible to make air (bubbles) hardly stay in the second thermostat chamber S2. Further, by inclining an axis L2 of the thermostat 13 0 with respect to the vertical direction, it is possible to shorten a height of the thermostat 130, at the same time, it is possible to arbitrarily determine a position where air stays in the inside of the thermostat 130. By forming a passage for bleeding air at the position, it is possible to efficiently perform the air bleeding. [0040] Further, by arranging the cooling water supply device 120 on a right side portion of the power unit 16 in a concentrated manner, the cooling water pipes (first to third cooling water pipes 144, 146a, 146b) are also arranged on the right side in a concentrated manner. Further, as shown in Fig. 11, these cooling water pipes and the cooling water discharging portion 121, the suction hole 147, the discharging hole 148 and the cooling water introducing portion 128 into which the cooling water flows or from which the cooling water flows out are arranged in a ladder shape in a side view and hence, the assembling and the maintenance of the cooling water pipes are facilitated. Further, due to such a constitution, it is possible to shorten a length of the bypass flow passage (third cooling water pipe 146b) which enables the circulation of the cooling water without passing the radiator 129. [0041] Here, the third cooling water pipe 146b which is bifurcated at the bifurcating portion 145 extends substantially vertically and downwardly and is connected to a cooling water pipe joint 141a (first introducing part 141) which is formed on the thermostat cover 130a. Accordingly, the third cooling water pipe 146b and at least a portion of the cooling water pipe joint 141a which projects outwardly from the thermostat cover 130a are covered with and protected by the radiator cover 152 in a side view. In the same manner, the discharging hole 148 of the radiator 129 and the second introducing portion 142 of the thermostat 130 are formed at a position where the discharging hole 148 of the radiator 129 and the second introducing portion 142 of the thermostat 130 are overlapped to each other in a side view and hence, it is possible to protect the connecting pipe 149 which connects the discharging hole 148 and the radiator 129 with the radiator cover 152. Here, in the inside of the engine 5 0 described in this embodiment, besides the above-mentioned cooling water supply device 120, the 02 sensor 116 which detects the oxygen concentration of the exhaust gas in the inside of the exhaust port 61 and the water temperature sensor 119 which measures the temperature of the cooling water in the inside of the water jacket 122 are mounted on the cylinder head 52. The 02 sensor mounting hole 116a and the water temperature sensor mounting hole 119a which mount these sensors 116, 119 therein are formed in the right side portion of the power unit 16 in the same manner as the cooling water introducing portion 121. Further, the axes of these mounting holes 116a, 119a are arranged substantially in parallel to the axis of the cooling water discharging passage 121a and hence, as shown in Fig. 5, the cooling water discharging portion 121, the 02 sensor 116 and the water temperature sensor 119 extend substantially in parallel to each other. Accordingly, the mounting of these sensors 116, 119 and the mounting of the first cooling water pipe 144 and the like on the cooling water discharging portion 121 can be performed from one side (right side) of the engine 50 and hence, the mounting operation can be facilitated. [Brief Description of the Drawings] [0043] [Fig. 1] A side view of a scooter-type vehicle on which a cooling water supply device according to the present invention is mounted. [Fig. 2] A plan view of a power unit. [Fig. 3] A left side view of the power unit. [Fig. 4] A right side view of the power unit. [Fig. 5] A cross-sectional view of a cylinder head. [Fig. 6] A side cross-sectional view of an essential part including a cooling water supply device. [Fig. 7] A plan cross-sectional view of an essential part including the cooling water supply device. [Fig. 8] A cross-sectional view of an essential part of the power unit including the cooling water supply device. [Fig. 9] A cross-sectional view of an essential part of a cylinder block. [Fig. 10] A front view of the power unit. [Fig. 11] An explanatory view showing the constitution of a cooling water flow passage. [Description of Reference Numerals and Signs] [0044] 50: engine 54: crank case 58: crank shaft 85: radiator fan 120: cooling water supply device 122: water jacket 125: cooling water pump 129: radiator 130: thermostat 130a: thermostat cover 5 141a: cooling water pipe joint 148: discharging hole 149: connecting pipe 152: radiator cover 154: valve element 10 SI: first thermostat chamber S2: second thermostat chamber [Designation of Document] Claims [Claim 1] A cooling water supply device which supplies cooling water for cooling an engine into a water jacket formed in the inside of the engine, the cooling water supply device comprising: a crankcase which supports a crankshaft rotatably driven by the engine; a cooling water pump which is driven by a driving force from the crankshaft and discharges the cooling water by pressurizing the cooling water; a radiator which is arranged on a side portion of the crankcase and radiates heat of the cooling water; and a thermostat which is arranged in a path between the radiator and the cooling water pump and allows the cooling water to flow into the radiator when a temperature of the cooling water is greater than a given value and allows the cooling water to bypass the radiator when the temperature of the cooling water is equal to or lower than the given value, wherein the cooling water pump is arranged on a side surface of the crankcase, and the thermostat is arranged in a space defined between the cooling water pump and the radiator. [Claim 2] A cooling water supply device according to claim 1, wherein a radiator fan which cools the radiator is provided to an end portion of the crankshaft, and the thermostat is arranged in front of and below the radiator fan in a side view. [Claim 3] A cooling water supply device which supplies cooling water for cooling an engine into a water jacket formed in the inside of the engine, the cooling water supply device comprising: a radiator which is arranged on a side portion of the engine and radiates heat of the cooling water; a radiator cover which covers the radiator, a cooling water pump which discharges the cooling water by pressurizing the cooling water; a thermostat which is arranged in a path between the radiator and the cooling water pump and allows the cooling water to flow into the radiator when a temperature of the cooling water is greater than a given value and allows the cooling water to bypass the radiator when the temperature of the cooling water is equal to or lower than the given value; and a thermostat cover which covers the thermostat, wherein a cooling water pipe joint to which a bypass passage allowing the cooling water which bypasses the radiator to flow therein is connected is formed on the thermostat cover, and the cooling water pipe joint is overlapped to at least a portion of the radiator cover in a side view, [Claim 4] A cooling water supply device according to claim 3, wherein the radiator and the thermostat cover are arranged in a state that the radiator and at least a portion of the thermostat cover are overlapped to each other, and a discharge hole which discharges the cooling water is formed at a portion where the radiator is overlapped to the thermostat cover in a side view, and the cooling water supply device includes a connecting pipe which connects the discharge hole and the inside of the thermostat cover. [Claim 5] A cooling water supply device according to any one of claims 1 to 4, wherein the thermostat has the inside thereof partitioned by a valve element provided inside thereof into a first thermostat chamber and a second thermostat chamber in a state that the first thermostat chamber and the second thermostat chamber become communicable with each other or non-communicable from each other and includes a first introducing portion and a second introducing portion which are respectively connected to the first thermostat chamber and the second thermostat chamber, and the first and second introducing portions are positioned at a height equal to or higher than upper ends of the first and second thermostat chambers in the vertical direction.

Full Text

[Designation of Document] Specification
[Title of the Invention] COOLING WATER SUPPLY DEVICE
[Technical Field]
[0001]
The present invention relates to a cooling water supply device which supplies cooling water to a water jacket formed in the inside of a cylinder head so as to cool the cylinder head.
[Background Art] [0002]
In efficiently generating power using an engine, there may be a case that it is preferable to set temperatures of a cylinder head and a cylinder block respectively. In this case, there has been known the structure in which a radiator is arranged on a side surface of a crankcase and, at the same time, a thermostat is arranged on a side of the cylinder head (see patent document 1, for example). [0003]
[Patent Document 1] JP-A-2003-172143 [Disclosure of the Invention] [Problems that the Invention is to Solve] [0004]
However, according to such a constitution, there lies a long distance between the cylinder head and the radiator and hence, a cooling water passage (cooling water pipe) is

elongated. Further, the radiator covers only an AC generator (ACG) in a side view and is not configured to cover other parts. Accordingly, there has been a drawback that a dead space is formed between the radiator and the engine. Further, since the thermostat is arranged on the cylinder head, there has been also a drawback that a periphery of a cylinder on which a large number of parts are arranged becomes further large-sized. [0005]
The present invention has been made under such circumstances and it is an object of the present invention to provide a cooling water supply device which can effectively make use of a dead space between a radiator and an engine while ensuring a space around a cylinder head. [Means for solving the problem] [0006]
To overcome the above-mentioned drawbacks, a cooling water supply device according to a first aspect of the present invention supplies cooling water for cooling an engine into a water jacket formed in the inside of the engine and includes a crankcase which supports a crankshaft rotatably driven by the engine, a cooling water pump which is driven by a driving force from the crankshaft and discharges the cooling water by pressurizing the cooling water, a radiator which is arranged on a side portion of the crankcase and radiates heat of the cooling water, and a thermostat which is arranged in a path

between the radiator and the cooling water pump and allows the cooling water to flow into the radiator when a temperature of the cooling water is greater than a given value and allows the cooling water to bypass the radiator when the temperature of the cooling water is equal to or lower than the given value, wherein the cooling water pump is arranged on a side surface of the crankcase, and the thermostat is arranged in a space defined between the cooling water pump and the radiator. [0007]
In the cooling water supply device according to the first aspect of the present invention, it is preferable that a radiator fan which cools the radiator is provided to an end portion of the crankshaft, and the thermostat is arranged in front of and below the radiator fan in a side view. [0008]
A cooling water supply device according to a second aspect of the present invention supplies cooling water into a water jacket formed in the inside of the engine and includes a radiator which is arranged on a side portion of the engine and radiates heat of the cooling water, a radiator cover which covers the radiator, a cooling water pump which discharges the cooling water by pressurizing the cooling water, a thermostat which is arranged in a path between the radiator and the cooling water pump and allows the cooling water to flow into the radiator when a temperature of the cooling water is greater

than a given value and allows the cooling water to bypass the radiator when the temperature of the cooling water is equal to or lower than the given value, and a thermostat cover which covers the thermostat; wherein a cooling water pipe joint to which a bypass passage allowing the cooling water which bypasses the radiator to flow therein is connected is formed on the thermostat cover, andthe cooling water pipe joint is overlapped to at least a portion of the radiator cover in a side view. [0009]
Here, it is preferable that the radiator and the thermostat cover are arranged in a state that the radiator and at least a portion of the thermostat cover are overlapped to each other, and a discharge hole which discharges the cooling water is formed at a portion where the radiator is overlapped to the thermostat cover in a side view, and the cooling water supply device includes a connecting pipe which connects the discharge hole and the inside of the thermostat cover. [0010]
In the cooling water supply devices according to the first and second aspects of the present invention, it is preferable that the thermostat has the inside thereof partitioned by a valve element provided inside thereof into a first thermostat chamber and a second thermostat chamber in a state that the first thermostat chamber and the second

thermostat chamber become communicable with each other or non-communicable from each other and includes a first introducing portion and a second introducing portion which are respectively connected to the first thermostat chamber and the second thermostat chamber, and the first and second introducing portions are positioned at a height equal to or higher than upper ends of the first and second thermostat chambers in the vertical direction. [Advantage of the Invention] [0011]
In the cooling water supply device according to the first aspect of the present invention having the above-mentioned constitution, since the thermostat is arranged between the radiator and the cooling water pump arranged in the crankcase, it is possible to effectively make use of a dead space defined between the radiator and the crankcase. Further, the thermostat constitutes a portion of a cooling water flow passage which allows the cooling water to flow into the cooling pump, it is possible to shorten the cooling water pipe in which the cooling water flows. Here, by arranging the thermostat in front of and below the radiator fan, it is possible to further make use of the dead space. [0012]
In the cooling water supply device according to the second aspect of the present invention having the

above-mentioned constitution, it is possible to protect the cooling pipe joint formed on the thermostat cover in a projecting manner with the radiator cover. Here, by forming the discharging hole at the position where the radiator and the thermostat cover are overlapped to each other, it is possible to shorten the distance between the radiator and the thermostat and, at the same time, it is possible to protect the connecting pipe with the radiator cover. [0013]
Here, by partitioning the inside of the thermostat using the valve element in a state that the first thermostat chamber and the second thermostat chamber become communicable with each other or non-communicable from each other and allowing the first introducing portion and the second introducing portion to be communicated with the first thermostat chamber and the second thermostat chamber which are portioned by the valve element, and, further, by constituting the first and second introducing portions that the first and second introducing portions are positioned at the height equal to or higher than upper ends of the first and second thermostat chambers in the vertical direction, it is possible to make air hardly stay in the inside of the first and second thermostat chambers without providing the particular structure for bleeding the air which stays in the inside of the first and second thermostat chambers.

[Best Mode for Carrying out the Invention] [0014]
Hereinafter, the preferred mode for carrying out the present invention is explained based on the attached drawings. Here, a scooter-type vehicle 1 on which a cooling water supply device according to the present invention is mounted is explained in conjunction with Fig. 1. The scooter-type vehicle 1 includes a vehicle body frame 2. The vehicle body frame 2 is constituted of a head pipe 3 which is arranged in front portion of the vehicle body frame 2 and extends in the vertical direction, a down frame 4 which extends below from the head pipe 3, a pair of left and right side frames 5 which extend downwardly, rearwardly and, thereafter, in the rearward upper oblique direction from a substantially center portion of the down frame 4, and an arcuate curve frame 7 which is mounted on the side frames 5 by way of a side plate 6. [0015]
A steering shaft not shown in the drawings is mounted on the head pipe 3 in a rotatable manner and a front fork 8 is mounted on a lower end of the steering shaft. A front wheel 9 is supported on a lower end of the front fork 8. On the other hand, a handle post 10 is mounted on an upper end of the steering shaft. Further, a handle 11 is mounted on an upper end of the handle post 10, and the front wheel 9 can be steered by manipulating the handle 11. Further, an upper stay 12 and a

lower stay 13 are mounted on the head pipe 3 in a state that the upper stay 12 and the lower stay 13 extend frontwardly from the head pipe 3. A front basket 14 is mounted on front ends of the upper and lower stays 12, 13. [0016]
A fuel tank 15 is mounted on lower portions of a pair of side frames 5 and between a pair of the side frames 5. A link mounting portion 48 which is formed on a front end of a power unit 16 is mounted on a rear end of the curved frame 7 which is positioned behind the fuel tank 15 in a vertically swingable manner and, at the same time, a rear end of the power unit 16 is mounted on a rear end of either one of the side frames 5 by way of a rear cushion unit 17. Here, a fuel pump 18 which includes a tumbling sensor therein is mounted on the fuel tank 15, and the fuel can be supplied to the fuel tank 15 from a fuel supply port (cap) 19 which is mounted on an upper portion of the fuel tank 15. Further, the power unit 16 is constituted of an engine 50, a transmission 90, a throttle body 21, an air cleaner 22, an exhaust pipe 23 which is extended rearwardly from the engine 50, and a muffler 24 which is connected to a rear end of the exhaust pipe 23. A rear wheel 25 is mounted on the rear end of the power unit 16. The rear wheel 25 is driven by the power unit 16 and hence, the scooter-type vehicle 1 obtains power and can travel. [0017]

A luggage box 26 and a grab rail 20 are mounted on the rear portion of the side frame 5. The luggage box 26 has a front portion thereof supported on a front side cross pipe 27 which is mounted on the side frame 5 by way of a front side plate 28, and has a rear portion thereof supported on a gate-type frame 29 mounted on the side frame 5. Further, the grab rail 20 is supported on a rear portion stay 3 0 which extends upwardly from the side frame 5. Here, helmets 31, 32 are shown in a state that the helmets 31,32 are accommodated in the inside of the luggage box 26. Further, a rear portion accommodating box 33 is mounted on a rear portion of the grab rail 20. [0018]
In the scooter-type vehicle 1 having the above-mentioned constitution, a front upper portion of the vehicle body is covered with a front cover 34 and left and right front side covers 35 are mounted on lower portions of side portions of the front cover 34 . A turn signal lamp not shown in the drawings is mounted on the front side cover 35. A front inner cover 36 is mounted on the rear portion of the front cover 34, and side portions of step floors 37 on which a driver and a pillion passenger place their foots are covered with side covers and under covers 38. Further, a seat 39 is mounted on the luggage box 26, and a lower periphery of the seat 39 is covered with a body cover and a body side cover 40. Still further, a handle cover 42 which covers a handle 11 is mounted above the front

cover 34, and a head lamp 43 is mounted on the handle cover 42. Further, a front fender 44 is mounted in a state that the front fender 44 covers the front wheel 9 from above and a rear fender 45 is mounted in a state that the rear fender 45 covers the rear wheel 25 from above. [0019]
Further, a tail lamp 46 is arranged below the grab rail 20 and a buttery 41 is accommodated between the front cover 34 and the front inner cover 36. [0020]
Next, hereinafter, the details of the power unit 16 are explained in conjunction with Fig. 2 to Fig. 5. Here, in this embodiment, an arrow F shown in Fig. 2 indicates the frontward direction, and an arrow U shown in Fig. 3 indicates the upward direction. An engine 50 which forms the power unit 16 is constituted of a cylinder head cover 51, a cylinder head 52, a cylinder block 53, and a crankcase 54. A cylinder sleeve 55 is fixed in a cylinder block 53. A cylinder chamber 55a is formed in a cylinder sleeve 55 in a state that the cylinder chamber 55a is surrounded by the cylinder sleeve 55, and a piston 56 is disposed in the cylinder chamber 55a in a vertically slidable manner. The piston 56 is connected to a crankshaft 58 which is rotatably supported in the inside of the crankcase 54 by way of a connecting rod 57. With a combustion chamber 59 which is defined by the cylinder block

53 (cylinder sleeve 55), the cylinder head 52 and the piston 56, an intake port 60 and an exhaust port 61 are communicated by way of an intake opening and an exhaust opening. Further, with respect to a mushroom-shaped intake valve 62 and a mushroom-shaped exhaust valve 63, one ends thereof are mounted on valve shafts and are supported by retainers, while another ends thereof are biased by valve springs 64, 65 which are supported on the cylinder head 52 in the direction that the intake valve 62 and the exhaust valve 63 normally close the intake opening and the exhaust opening. [0021]
Still further, a cam shaft 66 which performs the open/close operation of the intake valve 62 and the exhaust valve 63 is rotatably arranged in the cylinder head 52. The cam shaft 66 includes a cam driven sprocket 67 and the crankshaft 58. A timing chain 69 is wound around a cam driven sprocket 67 which is mounted on the cam shaft 66 and a cam drive sprocket 68 which is mounted on the crankshaft 58. Due to such a constitution, the cam shaft 66 is rotated in conformity with the rotation of the crankshaft 58 and cams 70, 71 which are formed on the cam shaft 66 pushes down the intake valve 62 and the exhaust valve 63 by way of rocker arms 72, 73 whereby the intake opening and the exhaust opening are opened and closed. Further, an injector 74 is mounted in the intake port 60 and hence, the fuel is atomized in a form of fine particles and

is jetted into the intake port 60 from the injector 74. Still Further, an ignition plug 75 is mounted on the cylinder head 52. [0022]
Here, a cam chain tensioner 84 which adjusts the timing of the opening/closing of the intake valve 62 and the exhaust valve 63 using the cams 70, 71 by adjusting a tension of the timing chain 69 is mounted on a side portion of the cylinder block 53. [0023]
In the inside of the engine 50 having such a constitution, the air-fuel mixture of air which is cleaned by the air cleaner 22 and fuel which is jetted from the injector 74 is supplied to the combustion chamber 59 from the intake port 60, and the air-fuel mixture is ignited by the ignition plug 75 and burnt after being compressed by the piston 56 and hence, the energy which rotates the crankshaft 58 by way of the piston 56 is generated. Thereafter, the exhaust gas is discharged to the outside from the exhaust port 61. [0024]
The crankshaft 58 is constituted of a right crankshaft two-split body 58a and a left crankshaft two-split body 58b. The connecting rod 57 is connected to the crankshaft 58 by way of a crank pin 76 which is arranged to join both of the crankshaft two-split bodies 58a, 58b. Further, the crankcase

54 which accommodates the crankshaft 58 is constituted of a right case two-split body 54a and a left case two-split body 54b. One end of the crankshaft 58 (a journal portion of the right crankshaft two-split body 58a) is supported on the right case two-split body 54a by way of a bearing 77, while another end of the crankshaft 58(a journal portion of the left crankshaft two-split body 58b) is supported on the left case two-split body 54b by way of a bearing 78. Further, an ACG 79 and a radiator fan 85 are arranged at a distal end portion of the journal portion of the right crankshaft two-split body 58a. [0025]
The left side portion of the left case two-split body 54b extends rearwardly and constitutes a portion of a transmission case 80, and a transmission 90 is accommodated in a transmission chamber 82 which is surrounded by a transmission cover 81 mounted on a left side surface of the left case two-split body 54b. The transmission 90 is constituted of a drive pulley 91 which is mounted on a distal end portion of a journal portion of the left crankshaft two-split body 58b which extends in the inside of the transmission chamber 82 and is integrally rotated with the left crankshaft two-split body 58b, a counter shaft 92 which is positioned behind the transmission chamber 80 f extends in parallel to the crankshaft 58 and is mounted in a rotatable

manner, a driven pulley 93 which is mounted on a substantially center portion of the counter shaft 92 in a relatively rotatable manner with respect to the counter shaft 92, a clutch 94 which is mounted on a left end of the counter shaft 92 and performs the engagement and the disengagement of the driven pulley 93 and the counter shaft 92, and a transmission belt not shown in the drawings which is wound around the drive pulley 91 and the driven pulley 93 and transmits the rotation of the drive pulley 91 to the driven pulley 93. [0026]
The drive pulley 91 is constituted of a fixed pulley two-split body 91a which is mounted on the crankshaft 58 in an integrally rotatable manner and a movable pulley two-split body 91b which is movable in the axial direction relative to the fixed pulley two-split body 91a and is integrally rotatable with the crankshaft 58. The transmission belt is sandwiched between the fixed pulley two-split body 91a and the movable pulley two-split body 91b. On the other hand, the driven pulley 93 is constituted of a fixed pulley two-split body 93a which is mounted on the counter shaft 92 in a relatively rotatable manner and a movable pulley two-split body 93b which is movable in the axial direction relative to the fixed pulley two-split body 93a and is rotatable relative to the to the counter shaft 92. The transmission belt is sandwiched between the fixed pulley two-split body 93a and the movable pulley

two-split body 93b. Accordingly, by variably setting pulley widths of the drive pulley 91 and the driven pulley 93, winding radii of the transmission belt to the both pulleys 91, 93 can be continuously changed whereby a transmission ratio can be controlled variably (continuously). [0027]
In parallel to the counter shaft 92, an idling shaft 95 and a rear wheel shaft 96 which mounts a rear wheel 25 thereon are provided in a rotatable manner. A rotational driving force of the counter shaft 92 is transmitted to the rear wheel 25 by way of the counter shaft 92, the idling shaft 95 and a gear train which is mounted on the rear wheel shaft 96. In this manner, an output of the engine 50 is transmitted to the crankshaft 58. Then, after receiving the change-gear operation of the transmission 90, the rotational drive force is transmitted to the rear wheel 25. [0028]
Here, when the above-mentioned power unit 16 is operated, the respective parts generate heat and hence, it is necessary to cool the respective parts. Accordingly, with respect to the cylinder head 52, a water jacket 122 is formed on the cylinder head 52 and the cylinder head 52 is cooled by the cooling water which flows in the inside of the water jacket 122. With respect to the cylinder block 53, a plurality of cooling fins 86 which project outwardly are formed on a side

portion of the cylinder block 53. The cooling fins 86 radiate heat generated in the cylinder block 53. Further, a cooling wind introducing passage 83 which takes outside air in the inside of the transmission chamber 82 is arranged in front of the transmission case 80 in a state that the cooling wind introducing passage 83 extends frontwardly. Due to such a constitution/ the transmission case 80 can be cooled. [0029]
Hereinafter, the cooling water supply device 120 which is used in the scooter-type vehicle 1 having the above-mentioned constitution is explained using also Fig. 6 to Fig. 10. The cooling water supply device 120 supplies the cooling water into the inside of a water jacket 122 which is mounted on the cylinder head 52 so as to cool the cylinder head 52. The cooling water supply device 120 is constituted of a cooling water pump 125 which pressurizes and discharges the cooling water, a radiator 129 which collects the cooling water used for cooling the water jacket 122 and irradiates the heat of the cooling water, and a thermostat 130 which, when a temperature of the cooling water indicates a value below given value, returns the cooling water to the water jacket 122 without performing the heat radiation of the cooling water using the radiator 129. [0030]
The cooling water pump 125 is mounted on one end of a

pump shaft 132 which extends substantially in parallel to the right crankshaft two-split body 58a* The cooling water pump 125 includes an impeller 131 which pressurizes the cooling water when the impeller 131 is rotated by the pump shaft 132. A pump driven sprocket 133 is mounted on another end of the pump shaft 132. Further, between the pump shaft 132 and the right crankshaft two-split body 58a, a pump idling shaft 134 which extends substantially in parallel to these shafts 58a and 132 is provided. On the pump idling shaft 134, a pump driven gear 136 which is meshed with a pump drive gear 135 joined to the right crankshaft two-split body 58a is mounted. Further, a pump drive sprocket 137 is mounted on the pump idling shaft 134 in a juxtaposed manner. Further, a pump chain 138 is wound around a pump drive sprocket wheel 137 and a pump driven sprocket wheel 133. Due to such a constitution, the rotation of the right crankshaft two-split body 5 8a which is generated by driving the engine 50 is transmitted to the pump idling shaft 134 by way of the pump drive gear 135 and the pump driven gear 136. The rotation of the pump idling shaft 134 is transmitted to the pump driven sprocket wheel 133 from the pump drive sprocket 137 by way of the pump chain 138 and the pump shaft 132 is rotated. Accordingly, the cooling water is pressurized and is discharged from the discharge opening 126 of the cooling water pump 125.

In front of the combustion chamber 59 formed in the cylinder head 52, the water jacket 122 which is a space formed so as to cover the combustion chamber 59 is provided. Further, the cylinder head 52 includes a cooling water discharge portion 121 on an upper side portion of the water jacket 122. In the cooling water discharge portion 121, a cooling water discharging passage 121a which is communicated with the outside and the water jacket 122 and discharges cooling water to the outside is formed. Further, the cylinder head 52 includes a cooling water introducing space 123 which is formed below and behind the water jacket 122 and also adjacent to the water jacket 122. The cooling water introducing space 123 opens at a rear side surface of the a lower portion of the cylinder head 52 and is communicated with the water jacket 122. [0032]
On the other hand, a cooling water introducing portion 128 which projects downwardly is formed on a lower side surface of a front portion of the cylinder block 53. In the cooling water introducing portion 128, a first passage 140a which has an introducing opening 128a which opens sideward and extends sideward and a second passage 140b which is communicated with the first passage 140a and extends frontward are formed (hereinafter, the first and second passages 140a, 140b are referred to as "cooling water introducing passage 140" as a general term). The second passage 140b includes a discharge

opening 128b which opens at a front end surface of the cylinder block 53. When the cylinder head 52 is mounted on the cylinder block 53, an opening portion (discharge opening 128b) of the second passage 140b is communicated with the opening portion of the cooling water introducing space 123 of the cylinder head 52 so that the cooling water introducing passage 140 is communicated with the water jacket 122. Further, a discharge opening 126 of the cooling water pump 125 and the cooling water introducing portion 128 formed in the cylinder block 53 are arranged close to each other and these discharge opening 126 and cooling water introducing portion 128 are connected by a cooling water supply pipe 127. [0033]
The thermostat 130 includes a first introducing portion 141 and a second introducing portion 142. The thermostat 130 is configured such that when a temperature of the cooling water which flows in the thermostat 130 from the first and the second introducing portions 141, 142 is equal to or below a given temperature, the second introducing portion 142 is closed and the cooling water is discharged to a discharge portion 143 from the first introducing portion 141, while when the temperature of the cooling water is higher than the given temperature, the first introducing portion 141 is closed and the cooling water is discharged to the discharging portion 143 from the second introducing portion 142. Further, a valve element 154 which

has an axis thereof inclined frontward in a side view is provided to the inside of the thermostat 130, wherein the inside of the thermostat 130 is partitioned to a first thermostat chamber SI which is communicated with the first introducing portion 141 and a second thermostat chamber S2 which is communicated with the second introducing portion 142 by the valve element 154. [0034]
To the cooling water discharging portion 121 formed on the cylinder head 52, a first cooling water pipe 144 is connected. The first cooling water pipe 144 is bifurcated to a second cooling water pipe 146a and a third cooling water pipe 146b at a branched portion 145. The second cooling water pipe 146a is connected to a suction hole 147 of the radiator 129, while the third cooling water pipe 146b is connected to the first introducing portion 141 of the thermostat 130. on the other hand, the second introducing portion 142 of the thermostat 130 is connected to a discharging hole 148 of the radiator 129 arranged in the vicinity of the second introducing portion 142 by way of a connecting pipe 149 having rigidity. At the branched potion 145, a positioning portion 145a which is used for performing the positioning when the first to third cooling water pipes 144, 146a, 146b are mounted is formed. [0035]
Here, a housing (thermostat cover 130a) which

accommodates the thermostat 130 therein is integrally formed with a housing which accommodates the cooling water pump 125 and hence, the discharge portion 143 of the thermostat 130 and a suction opening 150 of the cooling water pump 125 are directly connected with each other. Accordingly, the thermostat 130 constitutes a portion of a cooling water passage which supplies the cooling water to the suction opening 150 of the cooling water pump 125. By shortening a flow passage through which the cooling water flows, it is possible to allow the thermostat 130 to have a compact shape as a whole. Further, by providing the constitution which enables the connection of the radiator 129 and the thermostat 130 using the connection pipe 149, it is possible to enhance the assembling property of the power unit 16. [0036]
According to the cooling water supply device 120 having such a constitution, the cooling water discharged from the cooling water pump 125 flows in the water jacket 122 through the cooling water introducing passage 140 of the cooling water introducing portion 128 formed on the cylinder block 53. Further, the cooling water is discharged to the outside from the cooling water discharge portion 121 after cooling the cylinder head 52 . Although the discharged cooling water flows in the suction hole 147 of the radiator 129 or the first introducing portion 141 of the thermostat 130, when the

temperature of the cooling water is equal to or below a given value, since the second introducing portion 142 is closed by the thermostat 130, the cooling water returns to the cooling water pump 125 without passing through the radiator 129, while the temperature of the cooling water is higher than the given value, the first introducing portion 141 is closed by the thermostat 130 and hence, the cooling water returns to the cooling water pump 125 from the second introducing portion 142 after radiating heat through the radiator 129 and circulates. [0037]
In this manner, the intake opening for the cooling water (cooling water introducing portion 128) for cooling the cylinder head 52 is not formed in the cylinder head 52 but is formed in the cylinder block 53 and hence, the degree of freedom in designing the surrounding of the cylinder head 52 can be enhanced and, at the same time, it is possible to effectively make use of a dead space around the cylinder block 53. Here, as can be clearly understood from Fig. 4 or the like, the cooling water introducing portion 128 is mounted on a front end portion of the cylinder block 53, that is, is arranged in the vicinity of the cylinder head 52 and hence, the cooling water introducing passage 140 can be shortened as a whole whereby the cooling water introducing passage 140 can be light-weighted and, at the same time, a manufacturing cost can be reduced. Further, the forming of the cooling water introducing passage 140 in

the cylinder block 53 can be facilitated. [0038]
Here, such a cooling water supply device 120 is arranged in a concentrated manner on a right side portion of the power unit 16, wherein the radiator 129 is accommodated in the radiator cover 152 and the radiator outer cover 153 which are mounted on a right end portion of the right crankcase two-split body 54a. Here, the radiator 129 is arranged outside and remoter from the vehicle body than the radiator fan 85, and the thermostat 130 is arranged in front of and below the radiator 129 in a side view and, further, is arranged such that the cooling water pump 125, the thermostat 130 and a portion of the radiator 129 (radiator cover 152) are overlapped to each other in a side view. [0039]
Accordingly, the cooling water pump 125 can be arranged on the side portion of the crank case 54 and at a position close to the crank shaft 58 and hence, a driving force of the crank shaft 58 can be easily utilized. Further, the cooling water pump 125 and the thermostat 13 0 can be arranged in a space defined between the radiator 129(radiator cover 152) and the cylinder block 53 or the crank case 54 and hence, it is possible to effectively make use of a dead space and to make the whole structure compact. In the same manner, by arranging the thermostat 130 (thermostat caver 130a) between the cylinder

block 53 and the link mounting portion 48, it is possible to enhance the space utilization efficiency. Further, by arranging the thermostat 130 below the radiator 129, it is possible to make air (bubbles) hardly stay in the thermostat 130. Still further, a second thermostat chamber S2 which is communicated with the first introducing portion 142 is arranged below a line LI which extends in the horizontal direction from an upper end of the discharging opening 148. Accordingly, it is possible to make air (bubbles) hardly stay in the second thermostat chamber S2. Further, by inclining an axis L2 of the thermostat 13 0 with respect to the vertical direction, it is possible to shorten a height of the thermostat 130, at the same time, it is possible to arbitrarily determine a position where air stays in the inside of the thermostat 130. By forming a passage for bleeding air at the position, it is possible to efficiently perform the air bleeding. [0040]
Further, by arranging the cooling water supply device 120 on a right side portion of the power unit 16 in a concentrated manner, the cooling water pipes (first to third cooling water pipes 144, 146a, 146b) are also arranged on the right side in a concentrated manner. Further, as shown in Fig. 11, these cooling water pipes and the cooling water discharging portion 121, the suction hole 147, the discharging hole 148 and the cooling water introducing portion 128 into which the

cooling water flows or from which the cooling water flows out are arranged in a ladder shape in a side view and hence, the assembling and the maintenance of the cooling water pipes are facilitated. Further, due to such a constitution, it is possible to shorten a length of the bypass flow passage (third cooling water pipe 146b) which enables the circulation of the cooling water without passing the radiator 129. [0041]
Here, the third cooling water pipe 146b which is bifurcated at the bifurcating portion 145 extends substantially vertically and downwardly and is connected to a cooling water pipe joint 141a (first introducing part 141) which is formed on the thermostat cover 130a. Accordingly, the third cooling water pipe 146b and at least a portion of the cooling water pipe joint 141a which projects outwardly from the thermostat cover 130a are covered with and protected by the radiator cover 152 in a side view. In the same manner, the discharging hole 148 of the radiator 129 and the second introducing portion 142 of the thermostat 130 are formed at a position where the discharging hole 148 of the radiator 129 and the second introducing portion 142 of the thermostat 130 are overlapped to each other in a side view and hence, it is possible to protect the connecting pipe 149 which connects the discharging hole 148 and the radiator 129 with the radiator cover 152.

Here, in the inside of the engine 5 0 described in this embodiment, besides the above-mentioned cooling water supply device 120, the 02 sensor 116 which detects the oxygen concentration of the exhaust gas in the inside of the exhaust port 61 and the water temperature sensor 119 which measures the temperature of the cooling water in the inside of the water jacket 122 are mounted on the cylinder head 52. The 02 sensor mounting hole 116a and the water temperature sensor mounting hole 119a which mount these sensors 116, 119 therein are formed in the right side portion of the power unit 16 in the same manner as the cooling water introducing portion 121. Further, the axes of these mounting holes 116a, 119a are arranged substantially in parallel to the axis of the cooling water discharging passage 121a and hence, as shown in Fig. 5, the cooling water discharging portion 121, the 02 sensor 116 and the water temperature sensor 119 extend substantially in parallel to each other. Accordingly, the mounting of these sensors 116, 119 and the mounting of the first cooling water pipe 144 and the like on the cooling water discharging portion 121 can be performed from one side (right side) of the engine 50 and hence, the mounting operation can be facilitated. [Brief Description of the Drawings] [0043]
[Fig. 1] A side view of a scooter-type vehicle on which

a cooling water supply device according to the present invention is mounted.
[Fig. 2] A plan view of a power unit.
[Fig. 3] A left side view of the power unit.
[Fig. 4] A right side view of the power unit.
[Fig. 5] A cross-sectional view of a cylinder head.
[Fig. 6] A side cross-sectional view of an essential part including a cooling water supply device.
[Fig. 7] A plan cross-sectional view of an essential part including the cooling water supply device.
[Fig. 8] A cross-sectional view of an essential part of the power unit including the cooling water supply device.
[Fig. 9] A cross-sectional view of an essential part of a cylinder block.
[Fig. 10] A front view of the power unit.
[Fig. 11] An explanatory view showing the constitution of a cooling water flow passage. [Description of Reference Numerals and Signs] [0044] 50: engine 54: crank case 58: crank shaft 85: radiator fan
120: cooling water supply device 122: water jacket

125: cooling water pump 129: radiator 130: thermostat 130a: thermostat cover 5 141a: cooling water pipe joint 148: discharging hole 149: connecting pipe 152: radiator cover 154: valve element 10 SI: first thermostat chamber S2: second thermostat chamber

[Designation of Document] Claims [Claim 1]
A cooling water supply device which supplies cooling water for cooling an engine into a water jacket formed in the inside of the engine, the cooling water supply device comprising:
a crankcase which supports a crankshaft rotatably driven by the engine;
a cooling water pump which is driven by a driving force from the crankshaft and discharges the cooling water by pressurizing the cooling water;
a radiator which is arranged on a side portion of the crankcase and radiates heat of the cooling water; and
a thermostat which is arranged in a path between the radiator and the cooling water pump and allows the cooling water to flow into the radiator when a temperature of the cooling water is greater than a given value and allows the cooling water to bypass the radiator when the temperature of the cooling water is equal to or lower than the given value, wherein
the cooling water pump is arranged on a side surface of the crankcase, and
the thermostat is arranged in a space defined between the cooling water pump and the radiator. [Claim 2]
A cooling water supply device according to claim 1,

wherein a radiator fan which cools the radiator is provided to an end portion of the crankshaft, and
the thermostat is arranged in front of and below the radiator fan in a side view. [Claim 3]
A cooling water supply device which supplies cooling water for cooling an engine into a water jacket formed in the inside of the engine, the cooling water supply device comprising:
a radiator which is arranged on a side portion of the engine and radiates heat of the cooling water;
a radiator cover which covers the radiator,
a cooling water pump which discharges the cooling water by pressurizing the cooling water;
a thermostat which is arranged in a path between the radiator and the cooling water pump and allows the cooling water to flow into the radiator when a temperature of the cooling water is greater than a given value and allows the cooling water to bypass the radiator when the temperature of the cooling water is equal to or lower than the given value; and
a thermostat cover which covers the thermostat, wherein
a cooling water pipe joint to which a bypass passage allowing the cooling water which bypasses the radiator to flow therein is connected is formed on the thermostat cover, and
the cooling water pipe joint is overlapped to at least

a portion of the radiator cover in a side view, [Claim 4]
A cooling water supply device according to claim 3, wherein the radiator and the thermostat cover are arranged in a state that the radiator and at least a portion of the thermostat cover are overlapped to each other, and a discharge hole which discharges the cooling water is formed at a portion where the radiator is overlapped to the thermostat cover in a side view, and
the cooling water supply device includes a connecting pipe which connects the discharge hole and the inside of the thermostat cover. [Claim 5]
A cooling water supply device according to any one of claims 1 to 4, wherein the thermostat has the inside thereof partitioned by a valve element provided inside thereof into a first thermostat chamber and a second thermostat chamber in a state that the first thermostat chamber and the second thermostat chamber become communicable with each other or non-communicable from each other and includes a first introducing portion and a second introducing portion which are respectively connected to the first thermostat chamber and the second thermostat chamber, and
the first and second introducing portions are positioned at a height equal to or higher than upper ends of the first

and second thermostat chambers in the vertical direction.

Documents:

1918-CHE-2005 CORRESPONDENCE OTHERS 31-05-2012.pdf

1918-CHE-2005 AMENDED CLAIMS 19-09-2011.pdf

1918-CHE-2005 EXAMINATION REPORT REPLY RECEIVED 19-09-2011.pdf

1918-CHE-2005 FORM-3 19-09-2011.pdf

1918-CHE-2005 OTHER PATENT DOCUMENT 19-09-2011.pdf

1918-CHE-2005 POWER OF ATTORNEY 19-09-2011.pdf

1918-che-2005-abstract.pdf

1918-che-2005-claims.pdf

1918-che-2005-correspondnece-others.pdf

1918-che-2005-description(complete).pdf

1918-che-2005-drawings.pdf

1918-che-2005-form 1.pdf

1918-che-2005-form 3.pdf

1918-che-2005-form 5.pdf

1918-che-2005-other document.pdf

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Patent Number

253480

Indian Patent Application Number

1918/CHE/2005

PG Journal Number

30/2012

Publication Date

27-Jul-2012

Grant Date

25-Jul-2012

Date of Filing

26-Dec-2005

Name of Patentee

HONDA MOTOR CO., LTD.

Applicant Address

1-1 MINAMIAOYAMA 2-CHOME, MINATO-KU,TOKYO,JAPAN,

Inventors:

#	Inventor's Name	Inventor's Address
1	NUKADA,,YOSHITAKE	KABUSHIKI KAISHI HONDA GIJUTSU KENKYUSHO 4-1 CHUO 1-CHOME WAKO-SHI,SAITAMA,JAPAN;A JAPANESE CITIZEN
2	HIRAYAMA SHUJI	KABUSHIKI KAISHI HONDA GIJUTSU KENKYUSHO 4-1 CHUO 1-CHOME WAKO-SHI,SAITAMA,JAPAN;A JAPANESE CITIZEN

PCT International Classification Number

B63 B 13/02

PCT International Application Number

N/A

PCT International Filing date

PCT Conventions:

#	PCT Application Number	Date of Convention	Priority Country
1	2004-375393	2004-12-27	Japan