Title of Invention

"A COMPRESSED EQUIPPED WITH A PUMP CYLINDER BODY"

Abstract

There is provided a pump cylinder body 20, both ends of which are closed by first and second pump cylinder heads 231, and 232, and a pump piston 25 having at either end first and second piston heads 251,252 defining first and second pump chambers 361, 362 between first and second pump cylinder heads 231, 232. A pump crankshaft 26 and a connecting rod 40 coupling with this pump piston 25 are provided in an actuating chamber 37 provided in this pump piston 25. Reciprocating motion of the pump piston 25 is then controlled by the pump crankshaft 26.

Full Text

The present invention relates to a compressor equipped with a pump cylinder body. Field of the Invention The present invention relates to a compressor used, for example, for supercharging an internal combustion engine, and more particularly relates to a reciprocating compressor for drawing in a discharging gas using a reciprocal operation of a pump piston. Prior Art Conventionally, in order to supercharge internal combustion engines, a single piston compressor has been adopted where a pump piston defining a single pump chamber at a pump cylinder is coupled to a crankshaft, with pumping operations then being carried out at the pump chamber using the reciprocal motion of this pump piston. This is well known and is disclosed, for example, in Japanese Patent Publication No. Sho. 55-27218. Problems to be Solved by the Invention With the aforementioned single piston compressors, only one pump operation can be obtained for one reciprocal motion of the pump piston and the piston dimensions per unit discharge arc therefore large, meaning that it is difficult to make the compressor more compact. In order to resolve these problems, it is the object of the present invention to provide a reciprocating piston compressor that has small piston dimensions per unit discharge, that is compact and that provides superior durability. Means for Resolving the Problems The reciprocating compressor according to the present invention, equipped with a pump cylinder body having a cylinder hole with ends closed by first and second pump cylinder heads, and a pump piston slidably fitting into the cylinder hole and having first and second pistons heads at ends thereof and with first and second pump chambers being defined between the first and second pump cylinder heads, characterized in that an actuating chamber communicating between the pistons heads is formed at the pump piston, a crank pin ol'a pump crankshaft coupled with a rotary driving source and a connecting rod with one end coupled so as to swing freely to this crank pin and the remaining end coupled so as to swing freely to a piston pin provided at the pump piston are arranged in this actuating chamber, and reciprocal motion of the pump piston is controlled by rotations of the pump crankshaft. Owing to this characteristic, the total amount of gas discharged can be increased by operating first and second pumps using a single pump piston and it is therefore possible to make the dimensions of each part of the pump piston per total unit discharge smaller. Further, by adopting a connecting rod, changes in the speed of swinging of the connecting rod with respect to the piston pin during rotation of the pump crankshaft become smoother and the durability of bearing parts for the connecting rod supporting the piston pin can therefore be improved. In addition to the above characteristic, in a second characteristic of the present invention, an inlet valve for opening and drawing air into the pump chambers when the pump chambers are at low pressure and a discharge valve for opening and discharging air from the pump chambers when the pump chambers are at high pressure are provided at the first and second pump cylinder heads are provided. Owing to this characteristic, installation of the inlet valve and discharge valve is simplified and the compressor can therefore be made even smaller. In addition to the first characteristic, in a third characteristic of the present invention, the crank pin of the pump crankshaft fits into a first bearing hole formed at an end of the connecting rod via a needle bearing and the piston pin fits into a first bearing hole formed at the remaining end of the connecting rod via a needle bearing. Owing to this characteristic, the needle bearings have a small diameter and the load capacity is large. The coupling strength between the connecting rod, clamp pin and piston pin can therefore be increased and high speed motion can be sufficiently endured. In addition to the third characteristic, in a fourth characteristic of the present invention, first and second sealing members sandwiching the needle bearings and hermetically sealing the bearing holes are installed at the first and second bearing holes. Owing to this characteristic, flow of lubricating oil from the bearing holes can be prevented and the needle bearings can be effectively lubricated. In addition to the fourth characteristic, in a fifth characteristic of the present invention, an oil collecting chamber enclosing lubricating oil is formed at the connecting rod and the first and second bearing holes communicate with this oil collecting chamber. Owing to this characteristic, oil collecting chamber lubricating oil can be naturally supplied to the oil collecting chamber as a result of the expulsion power due to the reciprocal motion in accordance with swinging of the connecting rod and the needle bearings can be more effectively lubricated. In addition to the first characteristic, in a sixth characteristic of the present invention, the pump crankshaft is rotatably and freely supported at the pump cylinder body. Owing to this characteristic, the pump crankshaft can be solidly supported by an extremely rigid pump cylinder body. Therefore, the present invention relates to a reciprocating compressor equipped with a pump cylinder body comprising a cylinder hole with ends closed by first and second pump cylinder heads, and a pump piston slidably fitting into the cylinder hole and having first and second pistons heads at ends thereof and with first and second pump chambers being defined between the first and second pump cylinder heads, characterized in that an actuating chamber communicating between the pistons heads is formed at the pump piston that is constructed by directly joining the first and second piston heads, a crank pin of a pump crankshaft coupled with a rotary driving source and a connecting rod with one end coupled so as to swing freely to this crank pin and the remaining end coupled so as to swing freely to a piston pin provided at the pump piston are arranged in this actuating chamber, and reciprocal motion of the pump piston is controlled by rotations of the pump crankshaft. Brief Description of the Accompanying Drawings Fig. 1 is a vertical cross-sectional view of an internal combustion engine for a motorcycle equipped with a reciprocating piston compressor of the present invention. Fig. 2 is a cross-sectional view taken along line 2-2 of Fig. 1. Fig. 3 is a cross-sectional view taken along line 3-3 of Fig. 1. Fig. 4 is an enlarged vertical cross-sectional view of the internal combustion engine for a motorcycle shown in Fig. 1. Fig. 5 is a cross-sectional view taken along line 5-5 of Fig. 4. Fig. 6 is a cross-sectional view taken along line 6-6 of Fig. 4. Fig. 7 is a view from the perspective of arrow 7 in Fig. 4. Fig. 8 is an exploded top plan view of the main parts for the above-mentioned compressor. Fig. 9 is an exploded cross-sectional view of the main parts for the above-mentioned compressor. Fig. 10 is a diagram showing the opening/closing timing of the inlet, exhaust and supercharge valves for the above-mentioned internal combustion engine, and the acting timing of the pump piston for the above-mentioned compressor. Fig. 11 is a diagram showing the change in a rotational speed of the needle bearing at the side of the pump piston in the above-mentioned compressor. Fig. 12 is a sectional view showing an example of a deformation around the relief valve in the above-mentioned compressor. Description of the Preferred Embodiment A preferred embodiment of the present invention will now be described in detail with reference to the drawings. In Figs. 1 through 3, the symbol E denotes an internal combustion engine for a motorcycle equipped with a reciprocating piston compressor C of the present invention. The engine body 1 of the internal combustion engine E is structured with a cylinder head Ib boiled onto the upper end surface of a cylinder block la. On the cylinder head Ib are formed a combustion chamber 3 facing the head of a piston 2 housed in the cylinder block la, as well as an inlet port 4, an exhaust port 5 and a supercharge port 6 each communicating with the combustion chamber 3. Then, an inlet valve 7, an exhaust valve 8 and a supercharge valve 9 for opening and closing the inlet port 4. exhaust port 5 and supercharge port 6 respectively, a spark plug 10 for igniting an air-fuel mixture introduced into the combustion chamber 3, and a valve moving camshaft 1 1 for opening and closing the three valves 7, 8 and 9 are fixed onto the cylinder head Ib. On this occasion, they are so disposed that the supercharge valve 9 and spark plug 10 are in a V-shaped configuration with respect to the axial direction of the valve moving camshaft 1 1, and that the inlet valve 7 and exhaust valve 8 are in a V-shaped configuration in an orthogonal direction with respect to the axis of the valve moving camshaft 1 1. The valves 7, 8 and 9 are each mounted with valve springs 12, 13 and 14 which thrust them in a direction for them to close. The valve moving camshaft 1 1 is supported by the cylinder head Ib via a pair of ball bearings 15 left and 16 right. Between the bearings 15 and 16 are disposed an inlet cam 1 1 i and an outlet cam 1 le, and on the outwardly protruding end of the right bearing 16 is disposed a supercharge cam lie. On the outwardly protruding end of the left bearing 16 of the valve moving camshaft 1 1 is fixed a driven sprocket 18 driven via a chain 17 by a crankshaft (not shown) coupled with a piston 2. The inlet cam 1 li and the exhaust cam 11e arc connected with the inlet valve 7 and exhaust valve 8 via inlet and exhaust rocker arms 19i and 19 e, and the supercharge cam 1 1 c is connected direct with the supercharge valve in a tapering shape. Then, when the valve moving camshaft 11 is driven via the chain 17 by the crankshaft (not shown), working in combination with the inlet, exhaust and supercharge cams 11i, 11e and 11c as well as the valve springs 12, 13 and 14, the inlet, exhaust and supercharge valves 7, 8 and 9 open/close respectively according to the timing indicated in Fig. 10. The inlet port 4 and exhaust port 5 communicate, as in the case of a general internal combustion engine, with an inlet manifold and exhaust manifold (both not shown), but the supercharge port 6 communicates with a discharge conduit 57 of a reciprocating piston compressor C of the present invention, disposed adjacent to the outer edge of the supercharge cam 11c. In Figs. 4, 5 and 7, the reciprocating piston compressor C is equipped with a pump cylinder body 20 which has bearing bosses 21 and 22 protruded on the outer side surfaces left and right, a pump piston 25 which slidably fits into a cylinder hole 24 of the pump cylinder body 20, and a pump crankshaft which drives the pump piston 25. The pump cylinder body 20 is connected with bolts 28 with the left bearing boss 21 being fitted into a mounting hole 27 in the right side wall of the cylinder head 1 b (See Fig. 7). The pump piston 25 is not equipped with a piston ring. It is designed to slide directly inside the cylinder hole 24 of the pump cylinder body 20. The sliding surface thereof is applied with lubricating oil. The bearing bosses 21 and 22 have bearing holes 2 la and 22a which run to the inner surface of the pump cylinder body 20. The ball bearings 29 and 30 mounted on the bearing holes 21a and 22a support the pump crankshaft 26, while one end thereof is connected via a spline 3 1 with the valve moving camshaft 1 1. On the bearing hole 2 la is mounted an oil seal which comes into a close contact with the outer periphery of the pump crankshaft 26 at the outside of the bearing 29. The oil seal 32 is of a high pressure type structured strong enough to withstand pressures produced when a relief valve 75 (to be described later) opens. A seal plug 33 is mounted on the right bearing hole 22a adjacent to the outer peripheral surface of the bearing 30, and a cap 34 to cover the seal plug 33 is spirally mounted on the outer periphery of the bearing boss 22. Both ends of the cylinder hole 24 of the pump cylinder body 20 are closed by a pair of the primary' and secondary pump cylinder heads 23 1 and 232 , and primary and secondary piston heads 25 1 and 252 are formed at both ends of the pump piston 25, which define the primary and secondary pump chamber 361 and 362 between the pump cylinder heads 23 1 and 232. On the pump piston 25 are formed a circular actuating chamber 37 which goes through between the piston heads 25i and 252 being biased to the side of the primary piston head 252 as well as a piston pin hole 38 which goes through the primary piston heads 25 1 in a lateral direction to support a piston pin 39. A crank pin 26a of the pump crankshaft 26 and a connecting rod 40 which connects the crank pin 26a with the piston pin 39 are housed in the actuating chamber 37. The connecting rod 40 has a primary bearing hole 40a at the end of the side of the crank pin 26a, and a secondary bearing hole 40b at the end of the side of the piston pin 39. The crank pin 26a and piston pin 39 are supported respectively by primary and secondary needle bearings 41 and 42 mounted on the bearing holes 40a and 40b. A pair of left and right scaling members 43 and 43 are mounted on the primary bearing hole 40a in a close contact with the outer peripheral surface of the crank pin 26a with the primary needle bearing 41 interposed there-between. On the secondary bearing hole 40b are mounted a pair of left and right sealing members 44 and 44 in a close contact with the outer peripheral surface of the piston pin 39 with the secondary needle bearing 42 interposed in-between. In the connecting rod 40 is formed at the middle thereof an oil collecting chamber 46 which is covered tightly with a cap 45, and are drilled oil holes 47 and 48 for the oil collecting chamber 46 to communicate with the bearing holes 40a and 40b respectively. The oil collecting chamber 46 encloses lubricating oil. The pump piston 25 is divided, for ease of fabrication, into two piston half bodies 25a and 25b between the actuating chamber 37 and piston pin hole 38. The piston half bodies 25a and 25b are joined with two or more bolts 49. As shown in Figs. 4 through 6, the primary and secondary pump cylinder heads 23 1 and 23: are each provided, on the surface opposite to the pump cylinder body 20, with a fitting hole 50. a ring shaped discharge chamber 51 that is slightly smaller in diameter, and an inlet chamber 52 cylindrical in shape encircled in the discharge chamber 51. The pump cylinder heads 23 1 and 232 are joined together integrally with two or more through bolts 53 and nuts 54, with the fitting holes 50 being fitted in the outer periphery at both ends of the pump cylinder body 20. On both of the pump cylinder heads 23 1 and 232 are mounted a primary communicating tube 55 1 which communicates between the inlet chambers 52 and 52, as well as a secondary communicating tube 552 which communicates between the discharge chambers 5 land 51. Furthermore, the secondary pump cylinder head 232 is connected with an inlet conduit 56 which interconnects the inlet chamber 52 with the intermediate section of an inlet manifold (not shown) of the internal combustion engine E, as well as with a discharge conduit 57 which interconnects the discharge chamber 51 with the supercharge port 6 of the internal combustion engine E. Between the pump cylinder body 20 and each of the pump cylinder heads 23| and 232 is provided a valve unit 58 as follows in the fitting hole 50 thereof. That is, as shown in Figs. 8 and 9, the valve unit 58 is structured by stacking on top of the other in the sequence of a ring shaped back plate 60; a thin wall inlet valve plate 61, a valve seat plate 62 and a thin wall discharge valve plate 63. These components 60, 61, 62 and 63 are formed in a circular shape having an outer periphery that is approximately the same diameter as the end of the pump cylinder body 20. The valve unit 58 is fitted, with the back plate 60 being disposed on the end surface of the pump cylinder body 20, into the fitting hole 50 in the corresponding pump cylinder heads 23 1 and 232 together with the end of the pump cylinder body 20, and is interposed between the pump cylinder body 20 and each of the pump cylinder heads 23 1 and 232. As described above, the holding strength that is used is that that is used for connecting the primary and secondary pump cylinder heads 23 1 and 232 with the through bolt 53 and nut 54, with the pump cylinder body 20 being interposed in-between. On this occasion, a primary knock pin 65 1 is fitted into a primary positioning hole 64 1 provided in each of the pump cylinder heads 23 1 and 232, discharge valve plate 63 and valve seat plate 62, while a secondary knock pin 652 is fitted into a secondary positioning hole 642 provided in the valve seat plate 62, inlet valve plate 61 and back plate 60. In the valve seat plate 62 are drilled 4 sets of a set of 3 inlet holes 67 at the intervals of 90 degrees near and around the center thereof, as well as 2 sets of a set of 7 discharge holes 68 at the intervals of 180 degrees in proximity to the outer periphery thereof. In the inlet valve plate 61 are provided 4 inlet lead valves 6 la which correspond to the 4 sets of the inlet holes 67, as well as 2 circular long holes which surround but do not block the 2 sets of the discharge holes 68. Each of the inlet lead valves 61a is formed by cutting a slit in the inlet valve plate 61, which extends along the perimeter and in a radial direction thereof, with the base end being as close to the outer periphery of the inlet valve plate 61 and the other end being as close to the center of the inlet valve plate 61 as possible. On the inner periphery of the back plate 60 are provided notch shaped regulating sections 60a, which correspond to the base ends of the inlet lead valves 61a, to regulate the supports for deflection of the inlet lead valves 61a. The regulating sections 60a that are formed in a notch shape enable the length of deflection of the inlet lead valve 61a to be extended as long as possible without being hindered by the verge of opening of the cylinder hole 24 in the pump cylinder body 20. The length of deflection may be shortened, if desired, by forming the regulating section 60a in a convex shape. In the discharge valve plate 63 are provided 2 pieces of discharge lead valves 63a which correspond to the 2 sets of the discharge holes 68, as well as circular holes large in diameter which surround but not block the 4 sets of the inlet holes 67. The discharge lead valves 63a are formed by cutting a slit in the discharge valve plate 63 along the perimeter thereof. On the upper surface of the valve seat plate 62 is formed a ring shaped partition 62a which fits, through the circular hole 70, into the inner peripheral surface of the inlet chamber 52 of the corresponding pump cylinder heads 23 1 and 232 > thereby making a partition between the inlet chamber 52 and discharge chamber 51. As shown in Fig. 5. in the side wall of the pump cylinder body 20 are provided a valve mounting hole 71 which opens to the outer surface thereof, as well as a relief hole 72 which goes through the bottom wall of the valve mounting hole 71. A ring shaped groove 77 which interconnects the relief hole 72 with the actuating chamber 37 is formed on the inner peripheral surface of the pump cylinder body 20. A valve housing 73 is fitted airtight onto the outer periphery of the primary communicating tube 551,and two or more through holes 74 which interconnect the inside of the valve housing 73 with the inside of the primary communicating tube 551,are drilled in the wall of the primary communicating tube 551. In the valve housing 73 are housed a relief valve 75 which is able to open/close the relief hole 72, as well as a valve spring 76 which thrusts the relief valve 75 with a specified set load in a closing direction. In Fig. 4, the symbol 80 denotes an inspection hole provided in each of the pump cylinder heads 231 and 232. running to the inlet chamber 52. It is usually closed with a bolt 81. A description of how the embodiment acts will now be given below. When the pump crankshaft 26 of the compressor C is driven by the valve moving camshaft 11, while the internal combustion engine E is in motion, a reciprocating movement is forcefully imparted to the pump piston 25 via the connecting rod 40, which causes pressures in the primary and secondary pump chambers 36 1 and 362 to rise and fall alternately in repetition. When the pressure in the primary pump chamber 36| falls, closing the discharge hole 68 by the discharge lead valve 63a and opening the inlet hole 67 by the inlet lead valve 61a allows the air in the inlet manifold (not shown) of the internal combustion engine E to be suctioned from the inlet conduit 56 into the pump chamber 36 1 passing through the primary communicating tube 55 1, inlet chamber 52, and inlet hole 67. When the pressure in the pump chamber 36| rises, closing the inlet hole 67 by the inlet lead valve 61 a and opening the discharge hole 68 by the discharge lead valve 63a allows the pressurized air in the primary pump chamber 36 1 to be supplied to the supercharge port 6 of the internal combustion engine E via the discharge hole 68, discharge chamber 51, secondary communicating tube 552, and discharge conduit 57. Also, when the pressure in the secondary pump chamber 362 falls, as in the case of the primary pump chamber 36|, closing the discharge lead valve 63a and opening the inlet lead valve 61a allows the air in the inlet manifold of the internal combustion engine E to be suctioned from the inlet conduit 56 into the inlet chamber 52, inlet hole 67, and pump chamber 362 without passing through the primary communicating tube 551 When the pressure in the pump chamber 362 rises, as in the case of the primary pump chamber 36|. closing the inlet lead valve 61a and opening the discharge lead valve 63a allows the pressurised air in the primary pump chamber 362 to be discharged from the discharge hole 68 to the discharge chamber 51 and discharge conduit 57, without passing through the secondary communicating tube 552, so as to be supplied to the supercharge port 6 of the internal combustion engine E. On the other hand, in the internal combustion engine E, the inlet valve 7, exhaust valve 8 and supercharge valve 9 open/close according to the timing shown in Fig. 10. Particularly, the supercharge valve 9 is designed to open only for a certain period of time from just before the inlet valve 7 closes until it closes during the inlet and compression strokes. Then, when the supercharge valve 9 closes, high pressure air supplied as described above from the primary and secondary pump chambers 36\ and 362 is accumulated in the supercharge port 6, and high pressure air is supercharged from the supercharge port 6 into the combustion chamber 3 while the supercharge valve 9 is open, that is, during the time from the final stage of an inlet stroke until the initial stage of a compression stroke. As a result, the filling efficiency is enhanced, and a high output internal combustion engine E can be developed. In the compressor C, the primary and secondary pump chambers 361 and 362 are alternately put into operation by a single pump piston 25. Accordingly, the compressor C can be made more compact to a large extent by reducing the size of the pump pistons 25 per total unit discharge volume. Further, since the pump crankshaft 26 is supported on both side walls of the pump cylinder body 20 via the pair of the ball bearings 29 and 30, a stronger support of the pump crankshaft 26 may be achieved by a more rigid pump cylinder body 20. Moreover, since the pump piston 25 is driven by the pump crankshaft 26 via the connecting rod 40, a change in rocking speed of the connecting rod 40 with respect to the piston pin 39 is smooth while the pump crankshaft 26 is turning. Accordingly, as shown in Fig. 1 1. a change in rotational speed of the needle bearing 42 which supports the piston pin 39 is always smooth as well, which contributes to achieving a higher durability thereof. Also, since the pump piston 25 slides directly with no piston ring inside the cylinder hole 24 of the pump cylinder body 20, power loss due to sliding resistance may be kept low. However, the fact that the pump piston 25 has no piston ring means that it is impossible to avoid high pressure air in the pump chambers 36\ and 362 leaking into the actuating chamber 37 through a microscopic gap between the pump piston 25 and the inner peripheral surface of the cylinder hole 24; instead the use of this leakage for raising the pressure in the actuating chamber 37 contributes to reducing a difference between the pressure in the primary and secondary pump chambers 36i and 362 when pressurized and the pressure in the actuating chamber 37. As a result, the amount of air that is leaked into the actuating chamber 37 is reduced, which contributes to enhancing the working efficiency of the pump chambers 36i and 362 . When the inner pressure of the actuating chamber 37 has risen to a specified value or more, the relief valve 75 opens to release the excess pressure in the actuating chamber 37 to a low pressure of the primary communicating tube 552, preventing the pressure in the actuating chamber 37 from rising excessively as well as enhancing the durability of the oil seal 32 and other sealing sections, while preventing air leaking from the actuating chamber 37 into the cylinder head Ib of the internal combustion engine E. Then, since the air which has been released into the primary communicating tube 552, is suctioned again into the primary and secondary pump chambers 36i and 362, instead of being released into the atmosphere, there is no waste. Additionally, since the primary and secondary bearing holes 40a and 40b at both ends of the connecting rod 40 support, via the primary and secondary needle bearings 41 and 42, the crank pin 26a and piston pin 39, the needle bearings 41 and 42 have a large load-carrying capacity though they are comparatively small in diameter. Accordingly, the coupling strength between the pump crankshaft 26 and pump piston 25 is high enough to fully withstand a high speed operation. Moreover, since the bearing holes 40a and 40b have both of the ends sealed with a pair of the sealing members 43/43 and 44/44. and are interconnected via the oil holes 47 and 48 with the oil collecting chamber 46 formed at the intermediate section of the connecting rod 40, the oil in the oil collecting chamber 46 is naturally supplied to the bearing holes 40a and 40b by the action of centrifugal force when the connecting rod 40 is rocked with the turning of the pump crankshaft 26, thereby lubricating the needle bearings 41 and 42 as well as further enhancing the durability thereof. Additionally, since the back plate 60, inlet valve plate 61, valve seat plate 62 and exhaust valve plate which compose the valve unit 58 are all formed in a circular shape and have a perimeter approximately identical in the outer diameter with the end of the pump cylinder body 20, they can, together with the end of the pump cylinder body 20, be fitted into the fitting holes 50 in the corresponding pump cylinder heads 23 1 and 232 and interposed between the pump cylinder body 20 and pump cylinder heads 23 1 and 232. Accordingly, it contributes not only to making assembly of the valve unit 58 easy but also to protecting it from coming into contact with other objects by covering it with the pump cylinder heads 23 1 and 232- In this case, moreover, since the valve unit 58 is held in place by using the same force as is used when connecting the pump cylinder body 20 and pump cylinder heads 23 and 23 with the through bolts 53 and nuts 54, it eliminates mounting members dedicated to the valve unit 58, which contributes to making a simpler structure thereof. In addition, the fact that the primary knock pin 65 1 is fitted into the primary positioning hole 64| provided in the pump cylinder heads 23 1 and 232, discharge valve plate 63 and valve seat plate 62, as well as that the secondary knock pin 652 is fitted into the secondary positioning hole 64? provided in the valve seat plate 62, inlet valve plate 61 and back plate 60 enables the components to be easily and securely held at their position around the axis of the pump cylinder heads 23 1 and 232. Accordingly, the valve unit 58 is prevented from being assembled in an erroneous manner and proper valve actions may be secured at all times. Fig. 12 shows another embodiment of this invention. A seal cap 34' spirally fixed on bearing boss 22 on the right of the pump cylinder body 20 directly presses a ball bearing 30 on the right, and on the end wall of the seal cap 34' is provided a relief hole 72 and a valve mounting hole 71. In proximity to the seal cap 34', a primary communicating tube 55| is disposed and provided with a valve housing 73 which fits into the valve mounting hole 71. The valve housing 73 houses, as in the case of the previous embodiment, a relief valve 75 and a valve spring 76. A pump crankshaft 26 is provided with a through hole 82 which interconnects an actuating chamber 37 with the seal cap 34'. Because of the other components being the same as the previous embodiment, the corresponding components will be denoted by the same symbols as previously used, omitting a description thereof. In this embodiment also, excess pressure in the actuating chamber 37 may be released into a low pressure of the primary communicating tube 55\ from the relief hole 72. The invention, not being limited to the above-mentioned embodiments, may be embodied with various changes applied thereto without departing from the scope and essential characteristic features of the invention. [Effects of the Invention] Owing to the first characteristic of the present invention described above, because there is provided a pump cylinder body having a cylinder hole with ends closed by first and second pump cylinder heads, and a pump piston slidably fitting into the cylinder hole and having first and second pistons heads at ends thereof and with first and second pump chambers being defined between the first and second pump cylinder heads, characterized in that an actuating chamber communicating between the pistons heads is formed at the pump piston, a crank pin of a pump crankshaft coupled with a rotary driving source and a connecting rod with one end coupled so as to swing freely to this crank pin and the remaining end coupled so as to swing freely to a piston pin provided at the pump piston are arranged in this actuating chamber, and reciprocal motion of the pump piston is controlled by rotations of the pump crankshaft, the total amount of gas discharged can be increased by operating first and second pumps using a single pump piston and it is therefore possible to make the dimensions of each part of the pump piston per total unit discharge smaller. Further, by adopting a connecting rod, changes in the speed of swinging of the connecting rod with respect to the piston pin during rotation of the pump crankshaft become smoother and the durability of bearing parts for the connecting rod supporting the piston pin can therefore be improved. Further, owing to the second characteristic of the present invention described above, an inlet valve for opening and drawing air into the pump chambers when the pump chambers are at low pressure and a discharge valve for opening and discharging air from the pump chambers when the pump chambers are at high pressure are provided at the first and second pump cylinder heads are provided. Installation of the inlet valve and discharge valve is simplified as a result and the compressor can therefore be made even smaller. Owing to the third characteristic of the present invention, the crank pin of the pump crankshaft fits into a first bearing hole formed at an end of the connecting rod via a needle bearing and the piston pin fits into a first bearing hole formed at the remaining end of the connecting rod via a needle bearing so that the needle bearings can have a small diameter and the load capacity can be large. The coupling strength between the connecting rod, clamp pin and piston pin can therefore be increased and high speed motion can be sufficiently endured. Owing to the fourth feature of the present invention, first and second sealing members sandwiching the needle bearings and hermetically sealing the bearing holes are installed at the first and second bearing holes so that flow of lubricating oil from the bearing holes can be prevented and the needle bearings can be effectrvfely lubricated. Moreover, owing to the fifth feature of the present invention, an oil collecting chamber enclosing lubricating oil is formed at the connecting rod and the first and second bearing holes communicate with this oil collecting chamber. Oil collecting chamber lubricating oil can then be naturally supplied to the oil collecting chamber as a result of the centrifugal force due to the reciprocal motion in accordance with swinging of the connecting rod and the needle bearings can be more effectively lubricated. Still further, owing to the sixth characteristic of the present invention, the pump crankshaft is rotatably and freely supported at the pump cylinder body so that the pump crankshaft can be solidly supported by an extremely rigid pump cylinder body. Description of the Symbols C reciprocating piston compressor E rotary driving source 20 pump cylinder body 231 first pump cyl inder head 232 second pump cylinder head 24 cylinder hole 25 pump piston 251 first piston head 252 second piston head 26 pump crankshaft 26a crank pin 361 first pump chamber 362 second pump chamber 37 actuating chamber 39 piston pin 40 connecting rod 40a first bearing hole 40b second bearing hole 41 needle bearing 42 needle bearing 43 first sealing member 44 second sealing member 46 oil collecting chamber 47 oil hole 48 oil hole 61 a inlet valve (inlet lead valve) 63a discharge valve (discharge lead valve) WE CLAIM: 1. A reciprocating- compressor equipped with a pump cylinder body (20) comprising a cylinder hole (24) with ends closed by first and second pump cylinder heads (231,232), and a pump piston (25) slidably fitting into the cylinder hole (24) and having first and second pistons heads (251,252) at ends thereof and with first and second pump chambers (361,362) being defined between the first and second pump cylinder heads (231,232), characterized in that an actuating chamber (37) communicating between the pistons heads (251,252) is formed at the pump piston (25) that is constructed by directly joining the first and second piston heads (251,252), a crank pin (26a) of a pump crankshaft (26) coupled with a rotary driving source (E) and a connecting rod (40) with one end coupled so as to swing freely to this crank pin (26a) and the remaining end coupled so as to swing freely to a piston pin (39) provided at the pump piston (25) are arranged in this actuating chamber (37), and reciprocal motion of the pump piston (25) is controlled by rotations of the pump crankshaft (26). 2. The compressor as claimed in claim 1, wherein an inlet valve (6la) for opening and drawing air into the pump chambers (361, and 362) when the pump chambers (361, 362) are at low pressure and a discharge valve (63a) for opening and discharging air from the pump chambers (361, 362) when the pump chambers (361, 362) are at high pressure are provided at the first and second pump cylinder heads (231, 232). 3. The compressor as claimed in claim 1, wherein the crank pin (26a) of the pump crankshaft (26) fits into a first bearing hole (40a) formed at an end of the connecting rod (40) via a needle bearing (41) and the piston pin (39) fits into a first bearing hole (40b) formed at the remaining end of the connecting rod (40) via a needle bearing (42). 4. The compressor as claimed in claim 3, wherein first and second sealing members (43, 44) sandwiching the needle bearings (41, 42) and hermetically sealing the bearing holes are installed at the first and second bearing holes (40a, 40b). 5. The compressor as claimed in claim 4, wherein an oil collecting chamber (46) enclosing lubricating oil is formed at the connecting rod (40) and the first and second bearing holes (40a, 40b) communicate with this oil collecting chamber (46). 6. The compressor as claimed in claim 4, wherein the pump crankshaft (26) is rotatably and freely supported at the pump cylinder body (20). 7. A reciprocating compressor equipped with a pump cylinder body substantially as herein described with reference to the accompanying drawings.

Documents:

2114-del-1998-abstract.pdf

2114-del-1998-claims.pdf

2114-del-1998-correspondence-others.pdf

2114-del-1998-correspondence-po.pdf

2114-del-1998-description (complete).pdf

2114-del-1998-drawings.pdf

2114-del-1998-form-1.pdf

2114-del-1998-form-13.pdf

2114-del-1998-form-19.pdf

2114-del-1998-form-2.pdf

2114-del-1998-form-3.pdf

2114-del-1998-form-4.pdf

2114-DEL-1998-Form-6.pdf

2114-del-1998-gpa.pdf

2114-del-1998-petition-137.pdf

2114-del-1998-petition-138.pdf