Title of Invention

A COOLING SYSTEM FOR A WATER-COOLED ENGINE

Abstract

[Object] A thermostat, which controls, according to the temperature of cooling water,whether the cooling water from a water jacket is to be fed to a rediator or not, is attached to a cylinder block while avoiding an increase in size of the cylinder block. [Constitution] A thermostat 18 is mounted to a cylinder block 10 in such a manner that a axis of a slide hole 21 is parellel to the axes of cylinderbores, the thermostat 18 comprising a housing 20, a wax case 24, and wax, the housing 20 having an inlet hole 35 and an outlet hole 36 opposed to each other, the wax case 24 being slidably fitted in the housing 20 so as to be slidable berween a blocking position for establishing communication between the inlet and outlet holes 35 and 36, amd the wax being contained in the wax case 24 so as to permit the wax case 24 to slide in accordance with expansion and contraction of the wax caused by a change in temperature of cooling water. [Selected Drawing] Fig.3 Fig.1 R...Radiator

Full Text

FORM 2 THE PATENTS ACT 1970 [39 OF 1970] & THE PATENTS RULES, 2003 COMPLETE SPECIFICATION [See Section 10; rule 13] "A COOLING SYSTEM FOR A WATER-COOLED ENGINE" HONDA GIKEN KOGYO KABUSHIKI KAISHA, a corporation of Japan, having a place of business at 1-1, Minamiaoyama 2-chome, Minato-ku, Tokyo, Japan Or The following specification particularly describes the invention and the manner in which it is to be performed: 21-06-2001/25-01-2006 for a water-cooled engine in which a thermostat is attached to a cylinder block, the thermostat controlling, in accordance with the temperature of cooling water, whether cooling water from a water jacket provided in the cylinder block and a cylinder head is to be fed to a radiator or not. [Prior Art] Heretofore, such a cooling system has already been known, for example, in Japanese Patent Laid-Open No. Hei 10-16852. [Problem to be Solved by the Invention] In the conventional cooling system, however, the thermostat is attached to the cylinder block with a direction orthogonal to the axis of a cylinder bore formed in the cylinder block as an operating direction and is projected sideways from the cylinder block. Thus, the whole of the cylinder block with the thermostat thus attached thereto becomes larger in size. The present invention has been accomplished in view of such circumstances and it is an object of the present invention to provide a cooling system for a water-cooled 3 engine wherein a thermostat can be attached to a cylinder block while avoiding an increase in size of the cylinder block. [Means for Solving the Problem] For achieving the above-mentioned object, according to the invention defined in claim 1 there is provided a cooling system for a water-cooled engine wherein a water jack communicating with both a cylinder block having a cylinder bore and a cylinder head connected to the cylinder bore is provided, and a thermostat which controls, in accordance with the temperature of cooling water, whether cooling water from the water jacket is to be fed to a radiator or not, is attached to the cylinder block, characterized in that the thermostat includes a housing, a wax case, and wax, the housing having a slide hole, an inlet hole and an outlet hole which inlet and outlet holes are open opposedly to each other to an inner surface of the slide hole, the wax case being fitted in the slide hole so as to be slidable between a blocking position for blocking communication between the inlet hole and the outlet hole and a communicating position for establishing communication between the inlet and outlet holes, the wax being contained in the wax case so as to 4 permit the wax case to slide in accordance with expansion and contraction of the wax caused by a change in temperature of the cooling water, and the thermostat is attached to the cylinder block in such a manner that an axis of a slide hole is parallel to an axis of the cylinder bore. According to such a configuration of the invention defined in claim 1, since the operating direction of the thermostat is parallel to the axis of the cylinder bore, the thermostat even after attached to the cylinder block does not largely project sideways from the cylinder block and thus it is possible to prevent an increase in size of the cylinder block. Besides, since the thermostat can be positioned in proximity to the cylinder bore, the temperature sensing performance of the thermostat is improved and the thermostat is difficult to be influenced by the outside air, thus permitting improvement of the cooling performance. According to the invention defined in claim 2, in addition to the configuration of the invention defined in claim 1, a plurality of cylinder bores are formed side by side in the cylinder block, and the thermostat is 5 attached to the cylinder block at a position between a pair of adjacent cylinder bores. According to this configuration, since the thermostat is disposed by effectively utilizing the space between cylinder bores, an increase in size of the cylinder block after mounting of the thermostat thereto can be avoided more effectively. Moreover, since the thermostat can be positioned closer to cylinder bores, it is possible to further improve both temperature sensing performance of the thermostat and cooling performance. According to the invention defined in claim 3, in addition to the configuration of the invention defined in claim 1, a bottomed mounting hole for insertion and mounting therein of the thermostat is formed in the cylinder block so as to be open to the cylinder head side, an open end of the mounting hole being closed with the cylinder head to prevent disengagement of the thermostat from the mounting hole. According to this configuration, it is not necessary to use a special component for closing the mounting hole, whereby it is possible to not only reduce the number of components used but also improve the installing performance. Besides, it is possible to surely prevent the thermostat from being influenced by the outside air and thereby improve the cooling performance. 6 The present invention relates to a cooling system for a water-cooled engine wherein a water jacket (17) communicating with both a cylinder block (10, 10) having a cylinder bore (11) and a cylinder head (14) connected to the cylinder bore (11) is provided, and a thermostat (18) which controls, in accordance with the temperature of cooling water, whether cooling water from the water jacket (17) is to be fed to a radiator (R) or not, is attached to the cylinder block (10, 10) characterized in that the thermostat (18) comprises a housing (20), a wax case (24), and wax (28), the housing (20) having a slide hole (21), and inlet hole (35) and an outlet hole (36) which inlet and outlet holes are open opposedly to each other to an inner surface of the slide hole (21), the wax case (24) being fitted in the slide hole (21) so as to be slidable between a blocking position for blocking communication between the inlet hole (35) and the outlet hole (36) and a communicating position for establishing communication between the inlet and outlet holes, the wax (28) being contained in the wax case (24) so as to permit the wax case (24) to slide in accordance with expansion and contraction of the wax caused by a change in temperature of the cooling water, and the thermostate (18) is attached to the cylinder block (10, 10") in such a manner that an axis of the slide hole (21) is parallel to an axis of the cylinder bore (11). 7 [Brief Description of the Drawings] [Fig. 1] Fig. 1 is a vertical sectional view of principal portions of a cylinder block with a thermostat attached thereto and a cylinder head. [Fig. 2] Fig. 2 is a plan view of the cylinder block as seen in the direction of arrows 2-2 in Fig. 1. [Fig. 3] Fig. 3 is a vertical sectional view of the thermostat in a low temperature condition. [Fig. 4] Fig. 4 is a vertical sectional view of the thermostat in a high temperature condition. [Fig. 5] Fig. 5 is a sectional view of the thermostat taken along line 5-5 in Fig. 4. [Fig. 6] Fig. 6 is a sectional view of the thermostat taken along line 6-6 in Fig. 4. [Mode for Carrying Out the Invention] The present invention will be described hereinunder by way of embodiments thereof illustrated in the accompanying drawings. Figs. 1 to 6 illustrate the first embodiment of the present invention, of which Fig. 1 is a vertical sectional view of principal portions of both a cylinder block with a thermostat attached thereto and a cylinder head. Fig. 2 is a plan view of the cylinder block as seen in the direction of arrows 2-2 in Fig. 1, Fig. 3 is a vertical sectional view of the thermostat in a low temperature condition, Fig. 4 is a vertical sectional view of the thermostat in a high temperature condition, Fig. 5 is a sectional view of the thermostat taken along line 5-5 in Fig. 4, and Fig. 6 is a sectional view of the thermostat taken along line 6-6 in Fig. 4. First, in Figs. 1 and 2, four cylinder bores 11 are formed side by side in a cylinder block 10 of a four-cylinder engine mounted on a two-wheeled motor vehicle 9 10 for example and pistons 12 are slidably fitted in the cylinder bores 11, respectively. A cylinder head 14 is joined to the cylinder block 10, the cylinder head 14 defining combustion chambers 13 between it and the cylinder block 10, with crowns of the pistons 12 facing the combustion chambers 13, respectively. Intake valves 15 and exhaust valves 16 are disposed for opening and closing motions in the cylinder head 14 at positions opposed to the combustion chambers 13. In the cylinder block 10 and the cylinder head 14 is provided a water jacket 17 in communication with the two so as to surround the cylinder bores 11 and the combustion chambers 13. A thermostat 18 which controls, according to the temperature of cooling water, whether cooling water from the water jacket 17 is to be fed to a radiator R or not, is mounted to the cylinder block 10 at a position between a pair of adjacent cylinder bores 11 centrally in the arranged direction of the cylinder bores 11. In Figs. 3 and 4, a housing 20 of the thermostat 18 is formed in the shape of a stepped, bottomed cylinder which defines a slide hole 21 having one open end. A seal member 22 formed in the shape of a bottomed cylinder using an elastic material is affixed to the opposite end of the housing 20. A tip of the housing 20 is exposed as a tip reinforcing portion 20a to a central inner surface portion of the closed end of the seal member 22. The housing 20 is installed in the cylinder block 10 so that the axis of the slide hole 21 is parallel to the axes of the cylinder bores 11 in the cylinder block 10. A bottomed mounting hole 23 which receives the housing 20 therein is formed in the cylinder block 10 so as to be open on the cylinder head 14 side and at a position between a pair of adjacent cylinder bores 11 located centrally in the arranged direction of cylinder bores. An open end of the mounting hole 23 is closed with the cylinder head 14 when the cylinder head is joined to the cylinder block 10. Besides, the housing 20 is held between the closed end of the mounting hole 23 and the cylinder head 14 and is fixed within the mounting hole 23. A wax case 24 is slidably fitted in the slide hole 21 of the housing 20. The wax case 24 is composed of a case body 25 whose outer surface is brought into direct contact with the slide hole 21 and a cover 26 joined to the case body 25. The case body 25 is integrally provided with a cylindrical portion 25a of a reduced diameter, the cylindrical portion 25a being slidably fitted into the seal member 22 which is affixed to the opposite end of the housing 20. A peripheral edge portion of a diaphragm 27 is held between the case body 2 5 and the cover 26, and wax 2 8 is contained in the wax case 24 so as to be filled between the diaphragm 27 and the cover 26. The diaphragm 27 is deformed according to expansion and contraction of the wax 2 8 caused by a change in temperature of the wax. On the other hand, within the cylindrical portion 25a of a reduced diameter are slidably fitted a rod-like piston 29 in abutment against the tip reinforcing portion 20a of the housing 20, a disc-like plate 30 and a rubber piston 31 in this order from the side opposite to the diaphragm 26. A medium 32 for transferring the deformation of the diaphragm 26 to the rubber piston 31 is charged into the wax case 24 at a position between the rubber piston 31 and the diaphragm 26. A retaining ring 33 is fitted in an inner surface on one end side of the housing 20 and a spring 34 for biasing the wax case 24 to the opposite end side of the housing 20 is disposed between the retaining ring 33 and the wax case 24. When the temperature of cooling water is low and the wax 28 is in a contracted state, the wax case 24 lies in a blocking position on the opposite end side of the housing 20, as shown in Fig. 3. As the temperature of cooling water rises and the wax 28 expands, the diaphragm 26 is deflected downwards in Fig. 4 and the piston 31, which is in abutment against the tip reinforcing portion 20a, is pushed out from the cylindrical portion 25a of a reduced diameter, with the result that the wax case 24 slides to a communicating position on one end side of the housing 20 as in Fig. 4 while compressing the spring 34. Referring also to Fig. 5, an inlet hole 35 and an outlet hole 36 opposed to the inlet hole 35 are formed in the housing 20 so as to lie on one diametrical line of the slide hole 21. Communication between the inlet and outlet holes 35 and 36 is established and blocked according to slide motions of the wax case 24 which is slidably fitted in the housing 20. When the wax case 24 lies in the blocking position shown in Fig. 3, communication between the inlet and outlet holes 35 and 36 is blocked, while when the wax case 24 slides to the communicating position as in Fig. 4, the communication is established. Referring now to Fig. 1, the radiator R is connected through a cooling water conduit 37 to the water jacket 17 located on the cylinder head 14 side. A suction port of a water pump P is connected to the radiator R, while a discharge port of the water pump P is connected to one end of a cooling water conduit 38. An opposite end of the cooling water conduit 38 is connected to a water supply passage 39 formed in the cylinder block 10, the water supply passage 39 being in communication with the inlet hole 35 of the housing 20. Further, in the cylinder block 10 is formed a passage 40 coaxially with the water supply passage 39, the passage 40 functioning to let the outlet hole 36 of the housing 20 communicate with the water jacket 17. On an outer surface of the housing 20, as shown in Fig. 5, a pair of protuberances 41 are formed so as to extend in the axial direction of the housing 20, while grooves (not shown) for fitting therein of the protuberances 41 are formed in an inner surface of the mounting hole 22, whereby when the housing 2 0 is inserted and fixed into the mounting hole 22, the water supply passage 39 and the passage 40 are sure to be put in communication with the inlet hole 35 and the outlet hole 36, respectively. Referring also to Fig. 6, a bypass hole 42 is formed in the housing 20 at a position adjacent to the inlet hole 35. When the wax case 24 lies in its communicating position (the position shown in Fig. 4) for providing communication between the inlet and outlet holes 35 and 36, the bypass hole 42 is closed with the wax case 24, while as the wax case 24 slides to its blocking position (the position shown in Fig. 3), the bypass hole 42 is opened. On the other hand, a water chamber 43 is formed on one end side of the housing 20 and between the wax case 24 and the cylinder head 14. When the wax case 24 lies in its blocking position for blocking communication between the inlet and outlet holes 35 and 36, the bypass hole 42 communicates with the water chamber 43. Besides, a connecting pipe 44 which communicates with the water chamber 43 extends from the cylinder head 14 and is connected to the suction port of the water pump P through a bypass conduit 45. When the temperature of cooling water in the water jacket 17 is low, the thermostat 18 blocks communication between the inlet and outlet holes 35 and 36, and provides communication between the inlet hole 35 and the water chamber 43 through the bypass hole 42. As a result, the cooling water discharged from the water pump P flows through the thermostat 18 and returns to the water pump P. Thus, the cooling water present in the water jacket 17 is not fed to the radiator R. At the end of warming-up with raised temperature of the cooling water in the water jacket 17 the thermostat 18 provides communication between the inlet and outlet holes 35 and 36 and closes the bypass hole 42, thereby blocking communication between the inlet hole 35 and the water chamber 43. As a result, the cooling water discharged from the water pump P is fed from the thermostat 18 to the water jacket 17 and further flows from the water jacket 17 back to the water pump P through the radiator R. The operation of this first embodiment will now be described. Since the thermostat 18 is mounted to the cylinder block 10 in such a manner that its operating direction is parallel to the axes of the cylinder bores 11, the thermostat 19, even after the mounting thereof to the cylinder block 10, does not largely project sideways from the cylinder block 10. That is, an increase in size of the cylinder block 10 can be avoided. Besides, since the thermostat 18 can be disposed in proximity to the cylinder bores 11, the temperature sensing performance of the thermostat 18 can be improved and it is possible to diminish the influence of the outside air on the thermostat 18 and improve the cooling performance. Besides, in the cylinder block 10 wherein plural, say, four cylinder bores 11 are arranged side by side, the thermostat 18 is mounted at a position between a pair of cylinder bores 11 which are adjacent each other centrally in the arranged direction of the cylinder bores 11. Thus, the thermostat 18 can be disposed by effectively utilizing the space between adjacent cylinder bores 11 and the cylinder block 10 can be prevented more effectively from becoming larger in size by the mounting of the thermostat 18. Moreover, since the thermostat 18 can be disposed closer to the cylinder bores 11, the temperature sensing performance of the thermostat 18, as well as the cooling performance, can be further improved. Further, since the bottomed mounting hole 23 for insertion and mounting therein of the thermostat 18 is formed in the cylinder block 10 so as to be open on the cylinder head 14 side and the open end of the mounting hole 23 is closed with the cylinder head 14 to prevent disengagement of the thermostat from the mounting hole 23, it is not necessary to use any special part for closing the mounting hole 23 and it is possible to reduce the number of components used and improve the installing performance. Besides, the thermostat 18 can be prevented more surely from being influenced by the outside air and hence it is possible to further improve the cooling performance. Fig. 7 illustrates the second embodiment of the present invention, in which the portions corresponding the above first embodiment are identified by the same reference numerals as in the first embodiment. Four cylinder bores 11 are formed side by side in a cylinder block 10" and a bottomed mounting hole 23" is formed in the cylinder block 10" at a position outside the cylinder bore 11 located on one end side in the arranged direction of the cylinder bore 11, the mounting hole 23" being formed in parallel with the axes of the cylinder bores 11 so that an open end thereof is closed with a cylinder head 14 (see the first embodiment). Further, a thermostat 18, which controls, according to the temperature of cooling water, whether the cooling water from a water jacket 17 is to be fed to a radiator R (see Fig. 1) or not, is mounted to the cylinder block 10" while being inserted into the mounting hole 23". Also by this second embodiment there can be attained the same effects as in the previous first embodiment. Although embodiments of the present invention have been described above, the invention is not limited to the above embodiments, but various modifications may be made without departing from the scope of the invention described in the claims. For example, the housing 20 of the thermostat 18 may be formed in one piece with the cylinder block 10 (10") . [Effect of the Invention] As set forth above, according to the invention defined in claim 1, the thermostat, even after mounted to the cylinder lock, does not largely project sideways from the cylinder block and therefore it is possible to prevent an increase in size of the cylinder block. Besides, since the thermostat can be disposed in proximity to cylinder bores, the temperature sensing performance of the thermostat is improved and the thermostat is difficult to be influenced by the outside air, whereby the cooling performance can be improved. According to the invention defined in claim 2, the thermostat can be disposed by effectively utilizing the space between adjacent cylinder bores and an increase in size of the cylinder block after the mounting of the thermostat can be prevented more effectively. Additionally, the temperature sensing performance of the thermostat is further improved and it is also possible to further improve the cooling performance. Further, according to the invention defined in claim 3, not only the number of components used can be WE CLAIM: 1. A cooling system for a water-cooled engine wherein a water jacket (17) communicating with both a cylinder block (10, 10s) having a cylinder bore (11) and a cylinder head (14) connected to the cylinder bore (11) is provided, and a thermostat (18) which controls, in accordance with the temperature of cooling water, whether cooling water from the water jacket (17) is to be fed to a radiator (R) or not, is attached to the cylinder block (10, 10) characterized in that the thermostat (18) comprises a housing (20), a wax case (24), and wax (28), the housing (20) having a slide hole (21), and inlet hole (35) and an outlet hole (36) which inlet and outlet holes are open opposedly to each other to an inner surface of the slide hole (21), the wax case (24) being fitted in the slide hole (21) so as to be slidable between a blocking position for blocking communication between the inlet hole (35) and the outlet hole (36) and a communicating position for establishing communication between the inlet and outlet holes, the wax (28) being contained in the wax case (24) so as to permit the wax case (24) to slide in accordance with expansion and contraction of the wax caused by a change in temperature of the cooling water, and the thermostate (18) is attached to the cylinder block (10, 10) in such a manner that an axis of the slide hole (21) is parallel to an axis of the cylinder bore (11). 2. A cooling system for a water-cooled engine as claimed in claim 1, wherein a plurality of cylinder bores (11) are formed side by side in the cylinder block (10), and the thermostat (18) is attached to the cylinder block (10) at a position between a pair of adjacent cylinder bores (11). 3. A cooling system for a water-cooled engine as claimed in claim 1, wherein a bottomed mounting hole (23, 23") for insertion and mounting therein of the thermostat (18) is formed in the cylinder block (10, 10") so as to open to the cylinder head (14) side, an open end of the mounting hole (23, 23") being closed with the cylinder head (14) to prevent disengagement of the thermostat (18) from the mounting hole (23, 23").

Documents:

581-mum-2001-abstract(21-06-2001).doc

581-mum-2001-abstract(21-06-2001).pdf

581-mum-2001-cancelled pages(21-06-2001).pdf

581-mum-2001-claims(granted)-(21-06-2001).doc

581-mum-2001-claims(granted)-(21-06-2001).pdf

581-mum-2001-correspondence(20-08-2007).pdf

581-mum-2001-correspondence-(ipo)-(22-02-2006).pdf

581-mum-2001-drawing(21-06-2001).pdf

581-mum-2001-form 1(20-08-2007).pdf

581-mum-2001-form 1(21-06-2001).pdf

581-mum-2001-form 1(25-01-2006).pdf

581-mum-2001-form 13(20-08-2007).pdf

581-mum-2001-form 18(10-06-2005).pdf

581-mum-2001-form 2(granted)-(21-06-2001).doc

581-mum-2001-form 2(granted)-(21-06-2001).pdf

581-mum-2001-form 3(21-06-2001).pdf

581-mum-2001-form 3(25-01-2006).pdf

581-mum-2001-form 5(21-06-2001).pdf

581-mum-2001-petition under rule 137(25-01-2006).pdf

581-mum-2001-petition under rule 138(25-01-2006).pdf

581-mum-2001-power of authority(21-11-2001).pdf

581-mum-2001-power of authority(25-01-2006).pdf

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