The present invention relates to a suction structure in a piston type refrigerant compressor.
In a piston type compressor with a housing having formed therein a discharge chamber and a suction chamber, wherein refrigerant gas is supplied to the suction chamber from the outer periphery of the housing and discharged from the discharge chamber toward the outer periphery of the housing, the suction chamber is disposed on the radially outer side of the discharge chamber or on the radially inner side of an annular discharge chamber. A compressor with the suction chamber located on the outer side of the discharge chamber is disclosed in Japanese Utility Model Application Publication No. 59-105076 and Japanese Patent Application Publication No. 2000-120532 and a compressor with the suction chamber located on the inner side of the annular discharge chamber is disclosed in Japanese Patent Application Publication No. 7-233783.
In the compressor of the Japanese Utility Model Application Publication No. 59-105076, an oil reservoir is formed on the inner side of the annular discharge chamber and the suction chamber and the oil reservoir are connected through a communication passage extending across the discharge chamber. Lubrication oil separated from the refrigerant gas flowing through the communication passage is reserved in the oil reservoir.
In the compressor wherein the suction chamber is formed in the housing inward of the annular discharge chamber and refrigerant gas is supplied to the suction chamber from the outer periphery of the housing, it is desirable that the communication passage through which refrigerant gas is supplied to the suction chamber should be formed so as to extend across the discharge chamber in view of the need of downsizing the housing. If the discharge chamber is divided in the circumferential direction, discharge pulsation is not sufficiently suppressed. Therefore, it is desirable that the annular discharge chamber should not be divided by the communication passage, but formed as a single chamber, as disclosed in the Japanese Utility Model Application Publication No. 59-105076.
The Japanese Patent Application Publication No. 7-233783 discloses a compressor in which a plurality of ribs are formed in the discharge chamber thereby to form a plurality of small chambers. According to this Publication, since any two adjacent small chambers are not isolated but communicate with each other, the discharge pulsation is effectively suppressed. However, the Publication makes no reference to the structure of a suction passage extending across the discharge chamber to contribute to increasing the suction efficiency.
The present invention is directed to providing a piston type compressor in which refrigerant gas is supplied to a suction chamber from an outer peripheral region of the compressor outward of a discharge chamber located outward of the suction chamber, and which reduces the discharge pulsation and improves the suction efficiency.
A piston type compressor has a cylinder block, a cylinder bore formed in the cylinder block, a rotary shaft, a piston and a compression chamber formed in the cylinder bore. The piston is received in the cylinder bore and reciprocates in accordance with the rotation of the rotary shaft. The compressor further has a main suction chamber communicable with the compression chamber, a discharge chamber formed annularly so as to surround the main suction chamber, a subsidiary suction chamber formed so as to surround the discharge chamber, partitions formed in the discharge chamber so as to protrude into the discharge chamber and a suction passage formed in each partition so as to interconnect the subsidiary suction chamber and the main suction chamber.
Other aspects and advantages of the invention will become apparent from the following description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the invention.
The features of the present invention that are believed to be novel are set forth with particularity in the appended claims. The invention together with objects and advantages thereof, may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings in which:
The following will describe the first preferred embodiment of the fixed displacement double-headed piston type compressor according to the present invention with reference to
A rotary shaft 25 is rotatably supported by the front and rear cylinder blocks 11, 12 through front and rear radial bearings 26, 27. A swash plate 28 is secured to the rotary shaft 25. A shaft seal device 35 is interposed between the front housing 13 and the rotary shaft 25 so as to prevent refrigerant gas from leaking between the outer surface of the rotary shaft 25 and the front housing 13.
As shown in
As shown in
The front housing 13 has formed therein a plurality of partitions 33 (four partitions in the embodiment as shown in
Each partition 33 has formed therethrough a radial suction passage 331 interconnecting the subsidiary suction chamber 130 and the main suction chamber 131. A valve plate 16, valve forming plates 17, 18 and a retainer forming plate 19 are interposed between the front cylinder block 11 and the front housing 13. The valve plate 16, the valve forming plate 18 and the retainer forming plate 19 have formed therethrough a suction port 161, and the valve plate 16 and the valve forming plate 17 have formed therethrough a discharge port 162, respectively. The valve forming plates 17, 18 have formed therewith a suction valve 171 and a discharge valve 181, respectively. The suction valve 171 and the discharge valve 181 open and close the suction port 161 and the discharge port 171, respectively. The retainer forming plate 19 has formed therewith a retainer 191 for regulating the opening degree of the discharge valve 181.
The front cylinder block 11, the valve plate 16 and the front housing 13 have formed therethrough inlet and outlet passages 111, 112 extending in the axial direction of the rotary shaft 25. The inlet passage 111 communicates with the subsidiary suction chamber 130 and the outlet passage 112 communicates with the discharge chamber 132.
The partitions 33 are located so as to space apart each other along the circumferential direction of the annular discharge chamber 132. Therefore, the annular discharge chamber 132 is divided into a plurality of small chambers R1, R2, R3, R4 by the plurality of partitions 33, as shown in
As shown in
As shown in
Each partition 34 has formed therethrough a suction passage 341 interconnecting the subsidiary suction chamber 140 and the main suction chamber 141. As shown in
The rear cylinder block 12, the valve plate 20 and the rear housing 14 have formed therethrough an inlet passage 121 and an outlet passage 122 extending in the axial direction of the rotary shaft 25. The inlet passage 121 communicates with the subsidiary suction chamber 140 and the outlet passage 122 communicates with the discharge chamber 142, respectively.
As shown in
As shown in
The front and rear cylinder blocks 11, 12 have formed therethrough a plurality of pairs of front and rear cylinder bores 29, 30 (five cylinder bores in the embodiment as shown in
The rotational movement of the swash plate 28 rotatable integrally with rotary shaft 25 is transferred to the reciprocal movement of the double-headed piston 31 in its corresponding cylinder bores 29, 30 through shoes 32 provided in slide contact with the swash plate 28, with the result that compression chambers 291, 301 are formed in the cylinder bores 29, 30.
When the double-headed piston 31 moves rightward in
On the other hand, when the double-headed piston 31 moves leftward in
The refrigerant gas discharged into the discharge chambers 132, 142 flows out to the external refrigerant circuit through the outlet passages 112, 122 and the joint passage 124, respectively. The refrigerant gas flowed out to the external refrigerant circuit flows back into the subsidiary suction chambers 130, 140 through the main passage 123 and the inlet passages 111, 121, respectively. Then, the refrigerant gas flows into the main suction chambers 131, 141 through the suction passages 331, 341, respectively.
The above-described first embodiment of the present invention offers the following advantageous effects.
If there is only one partition 33, 34 in the discharge chamber 132, 142, respectively, the frequency of the contraction and expansion of the refrigerant gas is reduced, which is not desirable for the reduction of the discharge pulsation. If there is only one partition 33, 34 and hence only one suction passage 331, 341 in the discharge chamber 132, 142, the amount of the refrigerant gas flowing to the suction ports 161, 201 located far from the suction passages 331, 341 is smaller than that of the refrigerant gas flowing to the suction ports 161, 201 located close to the suction passages 331, 341, with the result that the suction efficiency deteriorates.
The structure of the discharge chamber with a plurality of partitions 33, 34 and hence with a plurality of small chambers R1 through R4 each corresponding to one cylinder bore 29 contributes to equalizing the amount of the refrigerant gas drawn through the respective suction ports 161, 201 thereby to improve the suction efficiency.
The following will describe the second embodiment with reference to
The rotary shaft 25 has formed therethrough an axial passage 38 extending in axial direction of the rotary shaft 25. The axial passage 38 communicates with the main suction chamber 131 through an inlet passage 135 formed in the front housing 13, so that the refrigerant gas in the main suction chamber 131 can be drawn into the axial passage 38 through the inlet passage 135. Since the inlet passage 135 communicates with the seal chamber 351, the lubrication oil in the main suction chamber 131 can flow to the seal chamber 351 thereby to lubricate the shaft seal device 35.
The axial passage 38 also communicates with the main suction chamber 141 in the rear housing 14, so that the refrigerant gas in the main suction chamber 141 can flow from the rear end of the rotary shaft 25 into the axial passage 38. The rotary shaft 25 in the shaft holes 36, 37 are formed with front and rear suction ports 381, 382 of the axial passage 38 which are opened to the front and rear seal surfaces 251, 252 of the rotary shaft 25, respectively.
As shown in
When the double-headed piston 31 moves leftward in
When the double-headed piston 31 moves rightward in
Thus, the front and rear seal surfaces 251, 252 of the rotary shaft 25 form front and rear rotary valves 41, 42, respectively, which are integrally formed with the rotary shaft 25. The front suction port 381 and the axial passage 38 cooperate to form a supply passage of the front rotary valve 41 and, similarly, the rear suction port 382 and the axial passage 38 cooperate to form a supply passage of the rear rotary valve 42.
The second embodiment also offers the same advantageous effects as the first embodiment. Since the piston type compressor 10A with the rotary valves 41, 42 inevitably has the main suction chamber located radially inward of the discharge chamber, the present invention may be applied suitably to the piston type compressor 10A with the rotary valves 41, 42.
The present invention is not limited to the embodiments described above, but it may be modified in various way as exemplified by the following alternative embodiments. The number of the partitions in the discharge chamber may be two, three or more than five. The present invention may be applied also to a variable displacement compressor as disclosed in the Japanese Patent Application Publications No. 7-233783 and No. 2000-120532.
The present invention is applicable further to a fixed displacement piston type compressor with a single-headed piston.
Number | Date | Country | Kind |
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2008-173652 | Jul 2008 | JP | national |