JP3520557B2 - Refrigerant gas suction structure in reciprocating compressor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerant in a reciprocating compressor which accommodates pistons in a plurality of cylinder bores arranged around a drive shaft and reciprocates the pistons in association with the rotation of the drive shaft. The present invention relates to a gas suction structure.

[0002]

2. Description of the Related Art Conventionally, each piston reciprocates in a plurality of cylinder bores formed in a cylinder block in parallel with a drive shaft, such as a swash plate compressor disclosed in Japanese Patent Laid-Open No. 5-71467. A reciprocating compressor that compresses a refrigerant gas is known. In this type of compressor, the drive shaft is inserted and supported in the central shaft hole of the cylinder block,
Each piston is linked to the swash plate in the crank chamber that cooperates with this drive shaft, and moves linearly in each cylinder bore. A housing is joined to the end surface of the cylinder block via a valve plate, and a discharge chamber for discharging the refrigerant gas compressed by the piston in the cylinder bore is formed in the housing. Further, between the cylinder bores and the central shaft hole in the cylinder block, there is formed a conduction path that radially connects the cylinder bores and the central shaft hole.

A rotary valve, which rotates in synchronization with the rotation of the drive shaft, is connected to the drive shaft. The rotary valve is formed with a suction passage that sequentially connects a communication passage connected to the cylinder bore in the suction stroke and a suction chamber as a suction passage in the central shaft hole. Further, the rotary valve includes a compression chamber of the cylinder bore that has completed the discharge of the compressed gas and a compression chamber of another cylinder bore that has already completed the suction of the compressed gas when the discharge of the cylinder bore is completed. A gas discharge path is formed so as to communicate with each other in synchronization with.

While the piston is in the suction stroke, the rotary valve rotates in synchronism with the drive shaft.
The refrigerant gas in the suction chamber is sequentially sucked into each cylinder bore through the suction passage and the communication passage. The discharge of the refrigerant gas from the inside of the cylinder bore to the discharge chamber is performed by moving the piston to the top dead center position, and the discharge port formed in the valve plate and the discharge port side of the discharge port are provided in the cylinder bore. And a discharge valve that opens the discharge port in response to pressure.

[0005]

In the above-described reciprocating compressor in which the piston reciprocates in the cylinder bore, in order to smoothly slide the piston, the outer peripheral surface of the piston and the inner peripheral surface of the cylinder bore are separated. Side clearance is provided between them. However, when the refrigerant gas in the compression chamber is pressurized by the movement of the piston to the top dead center side, the compression chamber is not set to a completely airtight state due to the side clearance between the piston and the cylinder bore, so that the high pressure state A part of the refrigerant gas will flow into the gap between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder bore.

Then, the inflow gas (blow-by gas)
Leaks out of the compression chamber along the inner peripheral surface of the cylinder bore. Such leakage leads to a decrease in the amount of refrigerant gas discharged from the compression chamber to the discharge chamber, which causes deterioration of discharge efficiency. The present invention has been made to solve the above problems, and an object thereof is to improve the efficiency of collecting blow-by gas that leaks between the outer peripheral surface of a piston and the inner peripheral surface of a cylinder bore. To provide a refrigerant gas suction structure in a reciprocating compressor capable of increasing the refrigerant gas suction efficiency.

[0007]

In order to solve the above problems, the invention according to claim 1 accommodates a piston in a plurality of cylinder bores arranged so as to surround a drive shaft with respect to a cylinder block, and By reciprocating the piston in conjunction with the rotation of the drive shaft, the refrigerant gas is sucked from the suction passage into the compression chamber defined by the piston in the cylinder bore, and the compressed refrigerant gas is discharged into the discharge chamber. In the reciprocating compressor configured as described above,
A housing hole provided in the cylinder block and positioned coaxially with the drive shaft; and a conduction path between the housing hole and the compression chamber for establishing communication between the housing hole and the compression chamber,
A suction passage that is slidably fitted in the accommodation hole and is supported so as to be rotatable in synchronization with the drive shaft, and that sucks a refrigerant gas from the suction passage to the compression chamber during the suction stroke, and
A gas discharge passage for communicating the conduction passage whose opening surface on the compression chamber side is closed by the outer peripheral surface of the piston and the conduction passage communicating with the compression chamber in the compression stroke starting state in synchronization with the rotation of the drive shaft. Is formed so as to penetrate the piston, and the blow-by gas leaking between the inner peripheral surface of the cylinder bore and the outer peripheral surface of the piston during the compression stroke is at least at the end of the compression stroke. The gist of the invention is to have a bypass passage leading to a conduction passage.

According to a second aspect of the present invention, in the first aspect of the invention, it is located between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder bore and communicates with the bypass passage at least at the end of the compression stroke. The gist of the present invention is to have a trapping groove. The invention according to claim 3 is the invention according to claim 1, wherein the outer peripheral surface of the piston is
At least a trapping groove communicating with the conduction path at the end of the compression stroke is provided, and the bypass passage has a first opening toward the drive shaft and a second opening at the first opening. The gist of the present invention is that the first and second openings of the bypass passage are provided in the vicinity of an extension of a straight line connecting the portion and the axial center of the piston, and are located on the trapping groove.

[0009]

With the above construction, in the invention according to the first aspect, the suction passage in the rotary valve is successively communicated with the plurality of compression chambers via the passage as the rotary valve rotates. This communication is performed in synchronization with the suction operation of the piston with respect to the compression chamber. When the suction passage and the compression chamber communicate with each other, the piston moves toward the bottom dead center side, and the pressure in the compression chamber decreases to the pressure in the suction passage (suction pressure) or less.
Due to this pressure decrease, the refrigerant gas in the suction passage flows into the compression chamber.

The gas discharge passage sequentially connects the passage of the compression chamber near the end of the compression stroke and the passage of the compression chamber at the start of the compression stroke with the rotation of the rotary valve. A part of the refrigerant gas in the compression chamber near the end of the compression stroke leaks from between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder bore, but this high-pressure leak gas (blow-by gas) is released to the outer peripheral surface of the piston. Stay in a bypass passage having a section. Then, the bypass passage in which the blow-by gas stays is moved by the piston toward the top dead center side,
It communicates with the communication path of the compression chamber in the state near the end of the compression stroke. Due to this communication, the high-pressure blow-by gas in the bypass passage is brought into the state of starting the compression stroke via the passage of the compression chamber in the state near the end of the compression stroke, the gas discharge passage, and the passage of the compression chamber in the state of starting the compression stroke. It flows into a certain compression chamber.

Further, in the invention described in claim 2, in addition to the function of the invention described in claim 1, a part of the refrigerant gas in the compression chamber in the state near the end of the compression stroke is formed in the outer peripheral surface of the piston and in the cylinder bore. This high-pressure blow-by gas is trapped in the trap groove, though it leaks from between the peripheral surface. The movement of the piston toward the top dead center causes the capture groove and the bypass passage to communicate with the conduction passage of the compression chamber in the state near the end of the compression stroke.

According to the third aspect of the invention, in addition to the action of the first aspect of the invention, a part of the refrigerant gas in the compression chamber in the state near the end of the compression stroke is in the piston outer peripheral surface and the cylinder bore. The high-pressure blow-by gas leaks from between the peripheral surface and the peripheral surface, but is also captured in the capture groove on the outer peripheral surface of the piston. The trap groove in which the blow-by gas stays and the bypass passage communicate with the passage of the compression chamber in the state near the end of the compression stroke due to the movement of the piston toward the top dead center side.
At that time, the blow-by gas in the trapping groove, which stays at the position farthest from the side of the conduction path, flows into the conduction path in the shortest distance by passing through the bypass passage.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment embodying the present invention will now be described with reference to FIGS.
It will be described with reference to FIG. As shown in FIG. 3, the front housing 3 and the rear housing 4 are joined to the end faces of the pair of joined front and rear cylinder blocks 1 and 2 via valve plates 5 and 6. Cylinder blocks 1 and 2, valve plates 5 and 6, front housing 3
The rear housing 4 is tightened and fixed by bolts 7, and the valve plates 5, 6 and both housings 3,
The pin 4 is prevented from rotating with respect to the cylinder blocks 1 and 2 by the pins 8 and 9. The cylinder blocks 1 and 2 are provided with tapered accommodating holes 1a and 2a in the center thereof, and annular positioning protrusions 1b and 2b are protruded from the opening edges of the accommodating holes 1a and 2a. Positioning protrusions 1b, 2
Valve plates 5 and 6 are fitted to b, and the valve plates 5 and 6 are positioned with respect to the cylinder blocks 1 and 2 by this fitting configuration.

Support holes 3a and 4a are formed in the central portions of the front housing 3 and the rear housing 4.
Conical roller bearings 10 and 11 are housed in the support holes 3a and 4a, and a drive shaft 12 is rotatably supported between the housings 3 and 4 via the conical roller bearings 10 and 11. A partition plate 13 is provided in the support hole 4a of the rear housing 4 on the free end side of the drive shaft 12 so as to engage with the rear surface of the conical roller bearing 11 so as to be movable back and forth. A seal ring 14 is interposed between the outer peripheral surface and the inner peripheral surface of the support hole 4a. This partition 1
A space A and a space B are formed before and after 3.

The thrust load acting on the drive shaft 12 from the front housing 3 side toward the rear housing 4 side is received by the rear housing 4 via the conical roller bearing 11 and the partition plate 13. The thrust load acting on the drive shaft 12 from the rear housing 4 side toward the front housing 3 side is received by the front housing 3 via the conical roller bearing 10.

A swash plate 15 is fixedly supported on the drive shaft 12. An inlet port 17 is formed in each of the cylinder blocks 1 and 2 that form the swash plate chamber 16 as an inlet channel, and an external inlet refrigerant gas pipe line (not shown) is connected to the inlet port 17. Refrigerant gas is introduced into the swash plate chamber 16 from the external suction refrigerant gas line through the inlet 17. Therefore, the swash plate chamber 16 becomes the suction pressure region.

As shown in FIGS. 4 and 5, a plurality of cylinder bores 1 are provided at equidistant angular positions about the drive shaft 12.
8a-18e and 19a-19e are formed. Figure 3
As shown in FIG.
e, 19a to 19e (five pairs in this embodiment), double-headed pistons 20a to 20e are reciprocally housed. Hemispherical shoes 21 and 22 are interposed between the double-headed pistons 20 a to 20 e and the front and rear surfaces of the swash plate 15. Therefore, the rotation of the swash plate 15 is converted into reciprocating motions in the cylinder bores 18a to 18e and 19a to 19e of the double-headed pistons 20a to 20e through the shoes 21 and 22.

On the other hand, the discharge chamber 2 is provided in both housings 3 and 4.
3 and 24 are formed, and double-headed pistons 20a to 20 are formed.
cylinder bores 18a-18e, 19a-1
Compression chambers Pa1 to Pa5, Pb1 to P divided into 9e
b5 is the discharge port 5a, 6 on the valve plate 5, 6
It is connected to the discharge chambers 23 and 24 via a. The discharge ports 5a and 6a are opened and closed by flapper valve type discharge valves 25 and 26, and the opening degree of the discharge valves 25 and 26 is the retainer 2
It is regulated by 7 and 28. Then, the discharge valves 25, 26
The retainers 27 and 28 are fixed to the valve plates 5 and 6 by bolts (not shown). Discharge chamber 2
3, 24 communicate with the external discharge refrigerant gas pipe line (not shown), and also communicate with the space B via the passage 4b.

As shown in FIG. 4, on the inner peripheral surface of the accommodation hole 1a, the same number of conduction passages 29a as the cylinder bores 18a to 18e are provided.
.About.29e are arranged at equidistant angular positions so as to always communicate with the cylinder bores 18a to 18e in a one-to-one correspondence.
Similarly, as shown in FIG. 5, on the inner peripheral surface of the accommodation hole 2a,
The same number of conduction paths 30a to 3 as the cylinder bores 19a to 19e.
0e are arranged at equiangular angular positions so that 0e always communicates with the cylinder bores 19a to 19e in a one-to-one manner.

As shown in FIGS. 1 and 2, the double-headed piston 20a is provided with an annular catching groove 31 on the outer peripheral surface thereof, and is set at a position separated by a predetermined distance L from the head side of the piston 20a. ing. Further, the double-headed piston 20a has a bypass passage 32 having an opening 32a, 32b on the trapping groove 31 and having a substantially circular cross section. The bypass passage 32 penetrates in the diametrical direction of the double-headed piston 20a, and has a cross-sectional area approximately equal to the cross-sectional area of the capture groove 31 defined by the outer peripheral surface of the double-headed piston 20a and the inner peripheral surfaces of the cylinder bores 18a, 19a. have.

As shown in FIG. 3, the opening 32a is arranged toward the drive shaft 12 side, that is, toward the conducting paths 29a and 30a, and the catching groove 31 and the conducting paths 29a and 30a near the end of the compression stroke. When communicating with each other, it is opened at a position facing the conducting paths 29a and 30a. The opening 32b is arranged on an extension of a straight line connecting the opening 32a and the axis of the double-headed piston 20a, that is, at a position 33 farthest from the side of the conducting paths 29a and 30a. The trapping groove 31 and the bypass passage 32 are provided in the double-headed pistons 20b to 20e in the same manner as the double-headed piston 20a.

On the drive shaft 12, rotary valves 34 and 35 having a tapered shape are fitted and supported by the drive shaft 12. Key grooves 36 and 37 that engage with the keys 12a and 12b fixed to the drive shaft 12 are provided on the rotary valves 34 and 35.
Is provided, and the rotary valves 34 and 35 are integrally rotatable with the drive shaft 12 and slidably accommodated in the accommodation hole 1
a, 2a. The accommodating holes 1a, 2a have a taper shape, and each of the accommodating holes 1a, 2a has a diameter that increases toward the swash plate chamber 16 side. And the rotary valve 3
4, 35 are fitted and inserted so that the outer peripheral surfaces thereof come into contact with the inner peripheral surfaces of the accommodation holes 1a, 2a. That is, the small diameter end 34a of the rotary valve 34 faces the discharge chamber 23 side, and the large diameter end 34b of the rotary valve 34 faces the swash plate chamber 16 side. Further, the small diameter end portion 35 a of the rotary valve 35 faces the discharge chamber 24 side, and the large diameter end portion 3 a of the rotary valve 35.
5b faces the swash plate chamber 16 side.

Large diameter ends 34 of the rotary valves 34, 35
In b and 35b, there are recesses 34c and
5c is formed, and the bottom wall of the recesses 34c and 35c and the swash plate 1 are formed.
Sealing force imparting springs 38 and 39 are interposed between the springs 5 and 5. The sealing force imparting springs 38, 39 urge the rotary valves 34, 35 from the large diameter end portions 34b, 35b side toward the small diameter end portions 34a, 35a side. Therefore, the outer peripheral surfaces of the rotary valves 34 and 35 come into close contact with the inner peripheral surfaces of the accommodation holes 1a and 2a by the spring force of the seal force imparting springs 38 and 39.

Further, as shown in FIG. 6, the rotary valve 3
Intake passages 40 and 41 are formed in the passages 4 and 35. The inlets of the suction passages 40, 41 open toward the swash plate chamber 16, and the outlets of the suction passages 40, 41 open on the outer peripheral surfaces of the rotary valves 34, 35. Guide grooves 42, 43 connected to the suction passages 40, 41 are provided on the outer peripheral surfaces of the rotary valves 34, 35 along the circumferential direction. Each of the above-mentioned conduction paths 29a to 29e, 30a to 29.
e is arranged in the circumferential region of the guide grooves 42 and 43.

Further, a gas discharge passage 44 (45) is formed on the outer peripheral surface of the rotary valve 34. The gas discharge passage 44 (45) is provided on the side opposite to the outlet of the suction passage 40 (41) with respect to the rotation center of the rotary valve 34, and the gas discharge passage 44 (45) is connected to the axial connecting groove 44 a (45 a). ) And both connection grooves 44a (45a) on the large diameter end 34b (35b) side.
b) and. Rotary valve 34 (3
The angular interval of the connection groove 44a (45a) with respect to the rotation center of 5) is set to be twice the angular interval of the arrangement of the conducting paths 29a to 29e (30a to 30e). The description of the rotary valve 35 is omitted by using the reference numerals in parentheses.

The support holes 3a, 4a communicate with the swash plate chamber 16 through the clearance between the drive shaft 12 and the rotary valves 34, 35. Therefore, the support holes 3a and 4a serve as suction pressure regions. Reference numeral 46 is a lip seal that seals the peripheral surface of the drive shaft 12. The lip seal 46 prevents the refrigerant gas from leaking from the support hole 3a to the outside of the compressor.

Next, the operation of the refrigerant gas suction structure in the reciprocating compressor having the above construction will be described. When the drive shaft 7 rotates in the direction of arrow Q shown in FIGS. 4 and 5, the refrigerant gas supplied into the swash plate chamber 16 is compressed into the compression chambers Pa1 to Pa1.
5, when the pressure inside Pb1 to Pb5 falls below the pressure inside the swash plate chamber 16, the passage 29a communicating with the guide grooves 42 and 43.
To 29e and 30a to 30e through compression chambers Pa1 to Pa
5, Pb1 to Pb5 are inhaled.

In the state shown in FIGS. 3, 4 and 5, the double-headed piston 20a is near the top dead center position with respect to the front cylinder bore 18a and near the bottom dead center position with respect to the rear cylinder bore 19a. In such a piston arrangement state, the outlet of the suction passage 40 is located immediately before communicating with the communication passage 29a of the cylinder bore 18a via the guide groove 42, and is connected to the connection groove 44a of the gas discharge passage 44 and the communication passage 29a of the cylinder bore 18a. Immediately after connecting. Then, when the double-headed piston 20a enters the intake stroke from the top dead center position to the bottom dead center position with respect to the cylinder bore 18a, the intake passage 40 communicates with the compression chamber Pa1 of the cylinder bore 18a via the guide groove 42. Due to this communication, the refrigerant gas in the swash plate chamber 16 passes through the suction passage 40 and the cylinder bore 18
It is sucked into the compression chamber Pa1 of a.

On the other hand, when the double-headed piston 20a enters the compression stroke from the bottom dead center position to the top dead center position with respect to the cylinder bore 19a, the suction passage 41 is closed.
The communication with the compression chamber Pb1 of 9a is cut off. Due to this disconnection, the refrigerant gas in the compression chamber Pb1 of the cylinder bore 19a is compressed as the double-headed piston 20a moves, and when it is compressed to a predetermined pressure, it is discharged from the discharge port 6a into the discharge chamber 24 while pushing out the discharge valve 26. .

Such suction and discharge of the refrigerant gas is similarly performed in the compression chambers Pa2 to Pa5 and Pb2 to Pb5 of the other cylinder bores 18b to 18e and 19b to 19e, and the refrigerant discharged to the discharge chambers 23 and 24 is discharged. The gas is pressure-fed to the external discharge refrigerant gas pipeline through an outlet (not shown).
Simultaneously with the compression of the refrigerant gas, the sucked refrigerant gas in the swash plate chamber 16 passes through the passage between the rotary valve 35 and the drive shaft 12 and is guided to the space A, where one of the discharged refrigerant gas in the discharge chamber 24 is discharged. The part is guided to the space B via the passage 4b. For this reason, a pressure difference is generated across the partition plate 13, and the partition plate 13 is pressed forward. As a result, a forward preload is applied to the conical roller bearing 11.

In the compression stroke, the double-headed piston 20
a to 20e are cylinder bores 18a to 18e, 19a to 1
When moving to the top dead center side with respect to 9e, the compression chamber Pa1
The pressures in -Pa5 and Pb1 -Pb5 gradually rise.
Meanwhile, the compression chambers Pa1 to Pa5, Pb1 are provided between the outer peripheral surfaces of the double-headed pistons 20a to 20e and the inner peripheral surfaces of the cylinder bores 18a to 18e, 19a to 19e (clearance).
A part of the refrigerant gas (blow-by gas) in Pb5 leaks. The blow-by gas is a two-headed piston 2.
It is captured by the capture groove 31 provided on the outer peripheral surface of 0a to 20e and stays in the capture groove 31 and the bypass passage 32.

First, as shown in FIG. 7, the double-headed piston 20a near the top dead center of one cylinder bore 18a is
Due to the outer peripheral surface thereof, the cylinder bore 18a of the communication path 29a is formed.
Close the side open surface. Then, with the closing, the communication path 29a is connected to the gas discharge path 44 on the rotary valve 34.
One of the connecting grooves 44a is connected to the other connecting groove 44a, and the other connecting groove 44a is connected to the conducting path 29c. Therefore, the passage 29a is connected to the compression chamber Pa3 through the gas discharge passage 44 and the passage 29c.
Be communicated to. The compression chamber Pa3 communicating with the conduction path 29a
Is in the compression stroke start state, and the compression chamber Pa3 in this state is
The internal pressure is not so different from the internal pressure of the compression chambers Pa4 and Pa5 in the suction stroke. Since the pressure of the residual gas in the conduit 29a is higher than the pressure in the compression chamber Pa3,
The residual gas passes through the gas discharge passage 44 and the compression chamber Pa
3 is released and the pressure in the conduit 29a drops to near the suction pressure. At this time, the passage 29c of the compression chamber Pa3 that has entered the compression stroke start state and the suction passage 40 are blocked by the outer peripheral surface of the rotary valve 34, so that the passage 29a is compressed via the gas discharge passage 44. The residual gas released into the chamber Pa3 does not flow out of the suction passage 40 into the swash plate chamber 16.

As shown in FIGS. 5 and 8, when the movement of the double-headed piston 20a toward the top dead center side further progresses, the conduction passage 29a is formed into the catch groove 31 and the opening 32 of the bypass passage 32.
It will communicate with a. Therefore, the blow-by gas trapped in the trap groove 31 and the bypass passage 32 becomes the same as the high pressure residual gas in the above-mentioned passage 29a.
It is discharged into the compression chamber Pa3 of the cylinder bore 18c in the compression stroke starting state through a, the gas discharge passage 44, and the communication passage 29c, and the pressure in the trap groove 31 and the bypass passage 32 is reduced to near the suction pressure. At this time, the blow-by gas that stays in the capture groove 31 near the position 33 farthest from the side of the conduction path 29a does not flow into the conduction path 29a through the capture groove 31 on the outer peripheral surface of the double-headed piston 20a and does not flow into the opening portion. 32
The bypass passage 32 that is the shortest distance from b to the conduction passage 29a
Will flow into the conduction path 29a. Therefore, it becomes possible to complete the discharge of the blow-by gas in a short section in which the conduction path 29a communicates with the capture groove 31 and the opening 32a of the bypass passage 32.

Curves D1, D3 and C3 in FIG. 9 are the compression chamber Pa1 and the compression chamber P with respect to the rotation angle of the rotary valve 34.
The pressure state in a3 is shown, and in particular, the curve C3 shows the pressure curve in the state in which the residual gas and blow-by gas according to the present invention flow. Here, the horizontal axis is the rotary valve 34.
Represents the rotation angle, and the vertical axis represents the compression chambers Pa1 and Pa3.
It represents the internal pressure. In this graph, the rotation angles when the double-headed piston 20a is at the top dead center position with respect to the compression chamber Pa1 are 0 °, 360 °, 720 ° ,. A curve D3 in the angular range θ is a pressure curve in a reciprocating compressor without the trap groove 31, the bypass passage 32 and the gas discharge passage 44. The curve C3 of the present invention during the compression stroke is set at an upper position as compared with the curve D3. This is because the pressure is increased by the refrigerant gas flowing from the trap groove 31 and the bypass passage 32 through the gas discharge passage 44. Therefore, the discharge pressure Pd section can be set longer in the compression stroke, and the discharge efficiency can be improved.

The action of transferring the refrigerant gas leaking from the compression chamber in the state immediately before the end of the compression stroke to another compression chamber in the state where the compression stroke is started is performed between compression chambers Pa2 and Pa4 and between compression chambers P2.
between a3 and Pa5, between compression chamber Pa4 and Pa1, compression chamber Pa5
, Pa2 is similarly performed. Of course, the compression chamber Pb1
The same process is carried out in the process of up to Pb5 by the trap groove 31 and the bypass passage 32.

As described in detail above, according to the refrigerant gas suction structure in the reciprocating compressor of the present embodiment, the outer peripheral surfaces of the double-headed pistons 20a to 20e and the cylinder bores 18a to 18e.
e, 19a to 19e and the inner peripheral surface of the compression chamber Pa.
The blow-by gas leaked from 1 to Pa5 and Pb1 to Pb5 does not flow into the swash plate chamber 16 and does not flow into the double-headed piston 20.
It will stay in the capture groove 31 and the bypass passage 32 of a to 20e. Therefore, the compression chambers Pa1 to Pa5, Pb1
The amount of the refrigerant gas flowing into Pb5 to Pb5 is the amount of the refrigerant gas sucked from the swash plate chamber 16 through the suction passages 40 and 41, and the gas discharge passage 44 from the trap groove 31 and the bypass passage 32.
It becomes the sum of the amount of the refrigerant gas that has flowed in via 45, and the refrigerant gas suction rate can be increased more than before. As a result, the volume efficiency of the compression chambers Pa1 to Pa5 and Pb1 to Pb5 can be improved, and the amount of compressed gas discharged per stroke in the compression stroke can be increased.

Further, when the blow-by gas is collected in the conduits 29 and 30, the bypass passage 32 is provided in the diameter portion of the annular trapping groove 31 provided on the outer peripheral surfaces of the double-headed pistons 20a to 20e. Passages 29a to 29e, 30
The blow-by gas staying at the position 33 farthest from the a to 30e side is promptly supplied to the conduction paths 29a to 29e, 30a to.
It is possible to lead to 30e, and it is possible to improve the recovery efficiency.

Further, since the conducting paths 29a to 29e and 30a to 30e are opened at positions slightly shifted from the top dead center side to the bottom dead center side so as to correspond to the trap groove 31, the high pressure near the end of the compression stroke. It is possible to reduce the amount of gas trapped by the outer peripheral surfaces of the double-headed pistons 20a to 20e. Therefore, the amount of re-expansion of the residual gas due to the retreat of the double-headed pistons 20a to 20e to the bottom dead center position can be reduced, and the compression chambers Pa1 to Pa5 and Pb1 to Pb5 in the suction stroke.
The volume efficiency of can be improved.

Further, the trapping groove 31 which improves the refrigerant gas suction efficiency can also serve as a lubricating groove due to the presence of lubricating oil contained in the refrigerant gas. The present invention is not limited to the above-described embodiments, and may be configured as follows, for example, within the scope of the invention. still,
The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

(1) In the above embodiment, the bypass passage 3
The number of the openings 2 is only two, that is, the openings 32a and 32b, but it is not limited to this and, for example, FIG.
As shown in (a), the through passage 4 connected to the opening 32a.
7 may be further provided. Further, a branch passage 48 may be provided as shown in FIG. 9 (b). In short, it is sufficient that the bypass passage 32 is formed on the capture groove 31 so as to shorten the distance to the side of the conductive passages 29 and 30.

The cross-sectional area and cross-sectional shape of the bypass passage 32 may be appropriately selected according to the compression ratio and capacity of the compressor used. (2) In the above embodiment, the rotary valves 34 and 35 having a tapered shape are used, but the present invention is not limited to this, and for example, as shown in FIG.
The outer peripheral surfaces of 4, 35 may be straight. In this case, the gas discharge passages 44 and 45 are connected to the compression passages Pa1 to Pa5 and Pb1 to Pb5 in the compression stroke.
It is desirable to set so as to surround e, 30a to 30e. In this way, the compression chamber Pa in the compression stroke
1 to Pa5, Pb1 to Pb5 conduction paths 29a to 29e,
Refrigerant gas leaking from 30a to 30e is supplied to the gas discharge passage 4
It can be captured at 4, 45.

(3) In the above embodiment, the double-headed piston 2
The bypass passage 32 having the trapping groove 31 and the openings 32a and 32b is provided in each of the double-headed pistons 20a to 20e.
Only the bypass passage 32 may be provided in a to 20e. In this case, in the double-headed pistons 20a to 20e, it is preferable that a large number of openings be provided in addition to the openings 32a and 32b, and it is preferable that the openings be provided at equal angular positions. Further, the opening may be locally provided depending on the driving method of the piston in the compressor or the compression ratio.
Further, it is not necessary to provide the trap groove 31 and the bypass passage 32 in all the double-headed pistons 20a to 20e. For example, only a trap groove 31 is provided for a certain piston, only a bypass passage 32 is provided for a certain piston, and a bypass passage 32 is provided for a certain piston. Both the capture groove 31 and the bypass passage 32 may be arranged in combination with.

(4) In the above embodiment, the bypass passage 3
2 and the trapping groove 31 had substantially the same cross-sectional area, but the present invention is not limited to this, and the bypass passage 32
And the trapping groove 31 may have different cross-sectional areas. (5) Although the swash plate chamber 16 is used as the suction passage in the above embodiment, the suction refrigerant gas may be introduced into the suction passages 40, 41 of the rotary valves 34, 35 by providing the suction passage in the housing. .

(6) In the above embodiment, the trapping groove 31 is provided on the outer peripheral surfaces of the double-headed pistons 20a to 20e, but it may be provided on the inner peripheral surfaces of the cylinder bores 18a to 18e and 19a to 19e. In this case, the capturing groove 31 is connected to the conductive paths 29a to 29a.
e, 30a to 30e are preferably provided so as to be connected. Also, the cylinder bores 18a to 18e, 19a to 19
In the inner peripheral surface of e, the catching groove 31 is connected to the conductive paths 29a to 29a.
e, 30a to 30e are provided so as to be shifted to the bottom dead center side, so that it is possible to reduce the amount of refrigerant gas remaining in the trap groove 31 by the outer peripheral surfaces of the double-headed pistons 20a to 20e.

(7) In the above embodiment, the present invention is embodied as a swash plate type double-headed piston compressor. However, a swash plate type one-sided piston compressor, a variable capacity type swash plate type compressor, an oscillating swash plate type compressor, or a special type. It may be embodied in a wave plate type compressor type as disclosed in Kaihei 5-026158.

[0046]

As described above in detail, according to the invention described in claim 1, the efficiency of collecting the blow-by gas leaking between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder bore is improved, so that the compression is performed. It has an excellent effect that the efficiency of sucking the refrigerant gas into the room can be increased.

Further, according to the invention described in claim 2, in addition to the effect of the invention described in claim 1, by providing the trapping groove between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder bore. The excellent effect that the blow-by gas can be completely captured is obtained. Further, according to the invention of claim 3, since the trapping groove is provided on the outer peripheral surface of the piston and the bypass passage is provided so as to connect the trapping groove, the trapping groove staying at the position farthest from the conduction path side is formed. The blow-by gas in the inside can be promptly guided to the conduction path by passing through the bypass passage, and in addition to the effect of the invention according to claim 1, it is possible to further improve the recovery efficiency. Produce the effect.

[Brief description of drawings]

FIG. 1 is a side view showing a double-headed piston of the present invention.

FIG. 2 is a cross-sectional view of a main part taken along the line AA of FIG.

FIG. 3 is a cross-sectional view showing the entire compressor.

FIG. 4 is a sectional view taken along line BB of FIG.

5 is a cross-sectional view taken along the line CC of FIG.

FIG. 6 is a perspective view of a rotary valve.

FIG. 7 is a schematic view of a main part showing a process of releasing residual gas.

FIG. 8 is a schematic view of a main part showing a process of releasing blow-by gas.

FIG. 9 is a graph showing the relationship between the rotation angle of the rotary valve and the pressure in the compression chamber.

FIG. 10 is a sectional view of a main part of a double-headed piston showing another example.

FIG. 11 is a perspective view showing another example of a rotary valve.

[Explanation of symbols]

1, 2 ... Cylinder block, 1a, 2a ... Housing hole, 12
... drive shaft, 16 ... swash plate chamber as suction passage, 18a-18
e, 19a to 19e ... Cylinder bore, 20a to 20e ...
Double-headed piston, Pa1 to Pa5, Pb1 to Pb5 ... compression chamber, 23, 24 ... discharge chamber, 29a to 29e ... conduction path, 3
1 ... Capture groove, 32a ... Opening portion as first opening portion, 3
2b ... Openings as second openings, 34, 35 ... Rotary valves, 40, 41 ... Suction passages, 44, 45 ... Gas discharge passages.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-71467 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F04B 27/08 F04B 39/10

Claims (3)

(57) [Claims] 1. A piston is housed in a plurality of cylinder bores arranged so as to surround a drive shaft with respect to a cylinder block, and the piston is reciprocated in association with the rotation of the drive shaft so that the piston is reciprocated. A reciprocating compressor configured to suck refrigerant gas into a compression chamber defined by the piston in a cylinder bore and discharge the compressed refrigerant gas to a discharge chamber, wherein the reciprocating compressor is provided in the cylinder block An accommodating hole located coaxially with the shaft, a conduction path between the accommodating hole and the compression chamber for establishing communication between the accommodating hole and the compression chamber, and a sliding contact fit with the accommodating hole, A suction passage, which is supported so as to be rotatable in synchronization with the drive shaft, and which sucks a refrigerant gas from the suction passage to the compression chamber during the suction stroke, and
A gas discharge passage for communicating the conduction passage whose opening surface on the compression chamber side is closed by the outer peripheral surface of the piston and the conduction passage communicating with the compression chamber in the compression stroke starting state in synchronization with the rotation of the drive shaft. A rotary valve formed with the piston, and the blow-by gas leaking between the inner peripheral surface of the cylinder bore and the outer peripheral surface of the piston during the compression stroke at least at the end of the compression stroke. A refrigerant gas suction structure in a reciprocating compressor having a bypass passage leading to a conduction passage. 2. A catch groove provided between the outer peripheral surface of the piston and the inner peripheral surface of the cylinder bore, the catch groove communicating with the bypass passage at least at the end of the compression stroke.
Refrigerant gas suction structure in the reciprocating compressor according to [4]. 3. A trapping groove is provided on the outer peripheral surface of the piston so as to communicate with the conduction path at least at the end of the compression stroke, and the first opening of the bypass path is provided near the drive shaft. Together with a second opening is provided in the vicinity of an extension of a straight line connecting the first opening and the axial center of the piston, the first and second openings of the bypass passage on the trapping groove. The refrigerant gas suction structure in the reciprocating compressor according to claim 1, comprising.