JPH06249144A - Refrigerant gas suction construction of reciprocating compressor - Google Patents

Abstract

PURPOSE:To reduce power loss required for driving of a compressor by suppressing a rolling friction between the tapered external surface of a rotary valve and the tapered internal surface of a storing chamber for storing it. CONSTITUTION:A suction passage 29 to introduce a refrigerant gas into a working chamber which is formed in a cylinder bore 13 by a piston 15 is formed in a rotary valve 27. Also a leading path 1b for connecting the working chamber to an outlet 29b of the suction passage 29 in a rotary valve 27 during suction stroke is formed on the tapered internal surface S of a storing chamber 1a for storing the valve 27. Then the position of a cylinder bore 13 side outlet 1c of the leading path 1b is set at a position closed by an external surface 15a of the piston 15 before the piston 15 moves to the top dead center of it. In addition, a bypass passage to lead refrigerant gas in a space into the other leading path 1b which is connected to the working chamber during compression is formed on a tapered external surface 27c with the inside of the leading path 1b close-spaced by the external surface 15a of the piston 15 and the tapered external surface 27c.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for a vehicle air conditioner in which a piston is housed in a plurality of cylinder bores arranged around a rotary shaft and the piston reciprocates in association with the rotation of the rotary shaft. The present invention relates to a refrigerant gas suction structure in a piston type compressor.

[0002]

2. Description of the Related Art In a conventional piston type compressor (see, for example, Japanese Patent Laid-Open No. 3-92587), a suction port between a working chamber and a suction chamber defined by a piston is provided by a flapper valve in the working chamber. It is designed to be opened and closed. The refrigerant gas in the suction chamber pushes the flapper valve open by the suction operation of the piston moving from the top dead center side to the bottom dead center side and flows into the working chamber. In the discharge stroke in which the piston moves from the bottom dead center side to the top dead center side, the flapper valve closes the suction port, and the refrigerant gas in the working chamber is discharged from the discharge port to the discharge chamber by pushing the discharge valve away.

The opening / closing operation of the flapper valve is based on the pressure difference between the working chamber and the suction chamber, and if the pressure in the suction chamber is higher than the pressure in the working chamber, the flapper valve flexes and deforms to open the suction port. . The pressure in the suction chamber becomes higher than the pressure in the working chamber during the suction operation of the piston moving from the top dead center side to the bottom dead center side.

[0004]

The flexural deformation of the flapper valve, which is an elastic deformation, acts as an elastic resistance, and the flapper valve does not open unless the pressure in the suction chamber exceeds the pressure in the working chamber to some extent. That is, opening of the flapper valve is delayed. Lubricating oil is mixed in the refrigerant gas in order to lubricate the inside of the compressor, and this lubricating oil is sent together with the refrigerant gas to a necessary lubrication site in the compressor. This lubricating oil can enter anywhere in the circulation region of the refrigerant gas, and the lubricating oil also adheres between the flapper valve that closes the suction port and its close surface. The adhered lubricating oil increases the close contact force between the close contact surface and the flapper valve, and the start of the flexural deformation of the flapper valve is further delayed. Such a delay in the start of flexural deformation causes a decrease in the amount of refrigerant gas flowing into the working chamber, that is, a decrease in volumetric efficiency. Further, even when the flapper valve is open, the elastic resistance of the flapper valve acts as a suction resistance, and the refrigerant gas inflow amount decreases.

Therefore, the applicant of the present application has proposed a piston type compressor capable of improving the compression efficiency. (For example, see Japanese Patent Application No. 4-211165) In this compressor, a suction passage for introducing a refrigerant gas into a working chamber defined by a piston in a cylinder bore is formed in a rotary valve. Further, the sliding contact peripheral surface of the rotary valve is tapered, and the inner peripheral surface of the accommodation chamber for accommodating the rotary valve is tapered. Further, the rotary valve is housed in the housing chamber so as to sequentially connect the working chamber and the suction passage in synchronization with the reciprocating motion of the piston and slidably in the axial direction of the rotary valve. A biasing spring urges the rotary valve from the large-diameter end portion side to the small-diameter end portion side to press the taper outer peripheral surface of the rotary valve against the taper inner peripheral surface of the accommodation chamber, and to seal between both taper peripheral surfaces. I try to apply force.

In this new compressor, when the piston moves to the top dead center, the conduction path is completely closed by the outer peripheral surface of the piston. Therefore, when the piston is at the top dead center, the high pressure of the working chamber in the cylinder bore acts on the tapered outer peripheral surface of the rotary valve through the conduction path, so that the tapered outer peripheral surface of the rotary valve is separated from the tapered inner peripheral surface of the accommodation chamber. Receives partial pressure in the direction. Then, the elastic force of the biasing spring that applies a sealing force between the tapered peripheral surfaces against the partial pressure is set. However, when this new compressor is used in an air conditioner for automobiles, the discharge pressure is 4-40 Kg /
It varies in the range of cm ² . Therefore, the maximum pressure is 40 kg /
Even in cm ² , the elastic force of the urging spring must be set large in order to press the rotary valve with a predetermined pressing force. Therefore, in the operating state of the compressor with a low cooling load and a low discharge pressure, the rotary valve is subjected to an excessive pressing force, causing friction between the taper outer peripheral surface of the rotary valve and the taper inner peripheral surface of the storage chamber. And a new problem arises that power loss increases. In addition, there is a problem that the sliding contact surface between the accommodation chamber and the rotary valve is scratched and durability is deteriorated.

Further, the applicant of the present application forms the outer peripheral surface of the above-mentioned rotary valve into a cylindrical shape and stores the rotary valve in a cylindrical storage chamber (for example, Japanese Patent Application No. No. 211164) is proposed.

In this compressor, in order to secure the sealing property of the sliding portion between the outer peripheral surface of the rotary valve and the inner peripheral surface of the accommodating chamber, the rotary valve is fitted on the rotary shaft so as to be synchronously rotatable with a slight clearance. Has been done. For this reason, when the pressure in the closed conduction path becomes equivalent to the discharge pressure, this high pressure acts in the radial direction on the cylindrical outer peripheral surface of the rotary valve. Therefore, the outer peripheral surface on the opposite side of the rotary valve is locally strongly pressed against the inner peripheral surface of the accommodation chamber, the power required to drive the compressor is increased due to the increase in the rotational sliding friction, and the sliding surface is There is a problem of wear.

According to the present invention, the problems existing in the above-described novel compressor are solved, and even if the discharge pressure fluctuates, the pressure in the closed communication passage acting on the outer peripheral surface of the rotary valve is set to the suction pressure and the discharge pressure. The pressure acting on the outer peripheral surface of the rotary valve is suppressed by maintaining an intermediate pressure between the rotary valve and the outer peripheral surface of the rotary valve, and the rotational sliding friction between the outer peripheral surface of the rotary valve and the inner peripheral surface of the accommodating chamber in sliding contact with the rotary valve is suppressed. Power loss can be reduced and durability can be improved. In addition, power of pressure in the closed conduction path can be recovered to improve compression efficiency and suction pulsation can be suppressed to reduce vibration and noise. An object of the present invention is to provide a refrigerant gas suction structure in a piston type compressor that can be used.

[0010]

To this end, according to the present invention, a storage chamber having an inner peripheral surface is provided for a cylinder block so as to be located between each cylinder bore and a rotary shaft, and the storage chamber has the inner peripheral surface. A rotary valve having an outer peripheral surface that is slidably fitted to the surface is housed. The rotary valve is supported on the rotary shaft so as to be rotatable in synchronism with the shaft, and the rotary valve is provided with a suction passage for sucking a refrigerant gas from the suction chamber to the working chamber during the suction stroke. A conduction path is formed between the accommodation chamber and the working chamber to connect both chambers. The position of the cylinder bore side outlet of the communication path is set to a position that is closed by the outer peripheral surface of the piston before the piston moves to the top dead center. Further, in the rotary valve, the conduction path is guided by the outer peripheral surface of the piston and the outer peripheral surface of the rotary valve to form a closed space, and the refrigerant gas in the space is guided into the conductive path communicating with the working chamber in the middle of compression. Form a bypass passage.

[0011]

The outlet on the tapered outer peripheral surface side of the suction passage formed in the rotary valve is communicated with the plurality of conductive passages in sequence as the rotary valve rotates. Therefore, the suction chamber and the working chamber are sequentially communicated with each other through the suction passage and the communication passage. This communication is performed in synchronization with the suction operation of the piston for each working chamber. When the suction passage and the working chamber communicate with each other, the piston moves toward the bottom dead center side, and the pressure in the working chamber decreases to the pressure in the suction passage (suction pressure) or less. Due to this pressure decrease, the refrigerant gas in the suction chamber flows into the working chamber through the suction passage and the communication passage.

During the discharge operation of the refrigerant gas, the communication between the suction passage and the working chamber during the compression stroke is blocked by the outer peripheral surface of the rotary valve, and the refrigerant gas in the working chamber is discharged to the discharge chamber when the pressure exceeds a preset pressure.

In the compression stroke in which the piston goes from the bottom dead center to the top dead center, the gas sucked into the working chamber is compressed and the pressure of the compressed gas rises in proportion to the movement of the piston. Then, before the piston moves to the top dead center where the pressure of the compressed gas becomes maximum, the working chamber side outlet of the conduction path that connects the suction passage and the working chamber is closed by the outer peripheral surface of the piston. As a result, the pressure in the conduction path is blocked in the intermediate force state, and when the outer peripheral surface of the rotary valve is cylindrical, the pressing force on the outer peripheral surface is suppressed. Therefore, the rotational sliding friction between the outer peripheral surface of the rotary valve and the inner peripheral surface of the accommodation chamber is reduced, the power required to drive the compressor can be suppressed, and the wear of the sliding contact surface can be suppressed. The durability can be improved.

Further, when the outer peripheral surface of the rotary valve is formed in a tapered shape and the outer peripheral surface of the taper is slidably in contact with the inner peripheral surface of the taper of the accommodation chamber, the pressure in the communication passage is the outer peripheral surface of the taper. Act on. Therefore, the rotary valve receives partial pressure in a direction away from the inner peripheral surface of the taper. Therefore, an urging member is used to press the rotary surfaces of the rotary valve into contact with each other to secure the sealing property, but the urging force of the urging member can be reduced. Therefore, the pressing force of the rotary valve by the biasing member is reduced. Therefore, the rotational sliding friction on the taper outer peripheral surface of the rotary valve is reduced, the power required to drive the compressor is reduced, and the sliding contact surface is prevented from biting.

In particular, in the present invention, the working chamber in the middle of compression of the refrigerant gas in the inner space of the conducting passage by the bypass passage in the state where the conducting passage is a closed space by the outer peripheral surface of the piston and the outer peripheral surface of the rotary valve. Is introduced into a communication path communicating with. Therefore, power loss is reduced as compared with the case where the refrigerant gas in the enclosed space is returned to the suction chamber.
In addition, blowback from the enclosed space in the communication path to the suction chamber is eliminated, suction pulsation is suppressed, and vibration of the compressor can be reduced.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is embodied in a swash plate type double-headed piston compressor will be described below with reference to the drawings.

In the center of the pair of front and rear cylinder blocks 1 and 2 joined as shown in FIG.
2a is pierced. Valve plates 3 and 4 are joined to the end surfaces of the cylinder blocks 1 and 2, and support holes 3a and 4a are formed through the valve plates 3 and 4, respectively.
An annular projection 3 for positioning is provided on the periphery of the support holes 3a, 4a.
b and 4b are projected, and the annular projections 3b and 4b are fitted in the accommodating chambers 1a and 2a. Valve plate 3,4
Also, pins 5 and 6 are inserted into the cylinder blocks 1 and 2, and rotation of the valve plates 3 and 4 with respect to the cylinder blocks 1 and 2 is blocked by the pins 5 and 6.

Support holes 3a, 4a for the valve plates 3, 4
A rotary shaft 7 is rotatably supported by conical roller bearings 8 and 9, and a swash plate 10 is fitted and fixed to the rotary shaft 7. The conical roller bearings 8 and 9 receive both thrust load and radial load on the rotating shaft 7.

An inlet 12 is formed in each of the cylinder blocks 1 and 2 forming the swash plate chamber 11, and an external refrigerant gas suction pipe line (not shown) is connected to the inlet 12.
As shown in FIGS. 2 and 3, the cylinder blocks 1 and 2 are formed with a plurality of cylinder bores 13 and 14 at equal angular positions about the rotary shaft 7. As shown in FIG. 1, a pair of front and rear cylinder bores 13 and 14 (5 pairs in this embodiment).
A double-headed piston 15 is housed therein so as to be capable of reciprocating. Hemispherical shoes 16, 17 are interposed between the double-headed piston 15 and both front and rear surfaces of the swash plate 10. Therefore,
When the swash plate 10 rotates, the double-headed piston 15 reciprocates in the cylinder bores 13 and 14.

As shown in FIG. 2, a front housing 18 is joined to the end surface of the cylinder block 1, and a rear housing 19 is also joined to the end surface of the cylinder block 2. The cylinder block 1, the valve plate 3 and the front housing 18 are fastened and fixed by bolts 21. The cylinder block 1, the cylinder block 2, the valve plate 4, and the rear housing 19 are fixed by bolts 22.

A discharge chamber 2 is provided in both housings 18 and 19.
3, 24 are formed. The working chambers Ra and Rb, which are divided into the cylinder bores 13 and 14 by the double-headed piston 15 and repeat suction and compression, communicate with the discharge chambers 23 and 24 via the discharge ports 3c and 4c on the valve plates 3 and 4, respectively. . The discharge ports 3c and 4c are opened and closed by flapper valve type discharge valves 31 and 32. The opening degrees of the discharge valves 31 and 32 are regulated by the retainers 33 and 34. Discharge valve 3
1, 32 and retainers 33, 34 are fastened and fixed on the valve plates 3, 4 by bolts (not shown). The discharge chamber 23 communicates with an external refrigerant gas discharge pipe line (not shown) through a discharge passage 25.

Reference numeral 26 denotes a discharge chamber 23 along the peripheral surface of the rotary shaft 7.
This is a lip seal that prevents refrigerant gas from leaking from the compressor to the outside of the compressor. Further, 26A and 26B are the annular projections 3b and 4 described above.
a discharge chamber 23 which is housed in b and extends along the peripheral surface of the rotating shaft 7;
It is a lip seal that prevents refrigerant gas from leaking from the swash plate chamber 11 to the swash plate chamber 11.

As shown in FIG. 2, rotary valves 27 and 28 are supported on the step portions 7a and 7b on the rotary shaft 7 so as to be slidable in the thrust direction. Rotary valve 2
A seal ring 39, 40 is provided between the rotary shaft 7 and the rotary shaft 7.
Is intervening. The rotary valves 27, 28 are rotatable integrally with the rotary shaft 7 in the direction of arrow Q in FIG.
a, 2a.

As shown in FIG. 2, the inner peripheral surfaces S of the accommodating chambers 1a and 2a are tapered, and the diameter increases from the end surfaces of the cylinder blocks 1 and 2 toward the inside. The outer peripheral surfaces 27c and 28c of the rotary valves 27 and 28 are the accommodation chamber 1
The taper has the same shape as a and 2a. Both taper outer peripheral surface 2
7c and 28c can be fitted exactly on the tapered inner peripheral surfaces S of the storage chambers 1a and 2a. That is, the large diameter end 27a side of the rotary valve 27 faces the swash plate chamber 11 side, and the small diameter end 27b side of the rotary valve 27 faces the discharge chamber 23 side. Further, the large diameter end 28a side of the rotary valve 28 faces the swash plate chamber 11 side, and the small diameter end 28b of the rotary valve 28.
The side faces the discharge chamber 24 side.

As shown in FIGS. 2 and 4, suction passages 29 and 30 are formed in the rotary valves 27 and 28, respectively. The inlets 29a, 30a of the suction passages 29, 30 open on the large-diameter end portions 27a, 28a.
0 outlets 29b, 30b are tapered outer peripheral surfaces 27c, 28c
It opens to the top.

As shown in FIGS. 2 and 3, on the taper inner peripheral surface S of the accommodation chamber 1a for accommodating the rotary valve 27, the same number of conduction passages 1b as the cylinder bores 13 are formed at equal angular intervals. The number of connecting paths 1b and the cylinder bore 13 is 1.
The communication paths 1b are always in communication with each other, and each of the conduction paths 1b is connected to the suction path 29.
It is located in the orbiting area of the exit 29b.

Similarly, on the taper inner peripheral surface S of the accommodation chamber 2a for accommodating the rotary valve 28, the same number of conduction passages 2b (only one is shown in FIG. 2) as the cylinder bores 14 are arrayed at equal angular intervals. There is. Conducting path 2b and cylinder bore 14
Are always in a one-to-one communication with each other, and each conduction path 2b is located in the circulation region of the outlet 30b of the suction passage 30.

Cylinder bore 1 of said conducting paths 1b, 2b
The positions of the outlets 1c and 2c on the 3,14 side are closed by the outer peripheral surface 15a of the piston 15 when the piston 15 is moved to a position away from the top dead center by a predetermined distance L as shown in FIG. It is set.

The swash plate chamber 11 is the suction pressure region, and the working chamber R
a and Rb change between the suction pressure region and the discharge pressure region.
Since the high-pressure refrigerant gas in the working chambers Ra and Rb in the discharge pressure region acts on the tapered outer peripheral surface 27c of the rotary valve 27 through the passages 1b and 2b, it enters the swash plate chamber 11 through the gap with the tapered inner peripheral surface S of the accommodation chamber 1a. Leak. This leakage is caused by the urging springs 35, 36 interposed between the boss portion of the swash plate 10 and the rotary valves 27, 28.
28 from the large diameter end 27a, 28a side to the small diameter end 27b,
It is prevented by urging toward the 28b side. That is, by this bias, the tapered outer peripheral surfaces 27c, 28c of the rotary valves 27, 28 are pressed against the tapered inner peripheral surfaces S of the accommodation chambers 1a, 2a, and the rotary valves 27, 28 are accommodated in the accommodation chamber 1
The taper inner peripheral surface S of a and 2a rotates while slidingly contacting. Therefore, the refrigerant gas discharged from the working chambers Ra and Rb is discharged from between the tapered outer peripheral surfaces 27c and 28c and the tapered inner peripheral surface S to the swash plate chamber 11
There is no leakage to the side.

Outer peripheral surface 27 of rotary valves 27, 28
The tapered structure of c and 28c prevents the discharged refrigerant gas from leaking and improves the volumetric efficiency. Moreover, the accommodation room 1
The work of inserting the rotary valves 27 and 28 into the a and 2a becomes easy.

Sliding contact peripheral surface 27 of rotary valves 27, 28
The configuration in which c and 28c are tapered brings further the following advantages. Sliding contact between the taper inner peripheral surface S of the storage chambers 1a, 2a and the taper outer peripheral surfaces 27c, 28c of the rotary valves 27, 28 causes wear on the slide contact peripheral surfaces, but the rotary valves 27, 28 have the storage chambers 1a, 2a. Always makes good sliding contact with. That is, the seal between the rotary valves 27 and 28 and the storage chambers 1a and 2a has a self-replenishing function, and the sealing performance does not deteriorate. Rotary valves 27, 28
Even if the linear expansion coefficient of the cylinder block and the linear expansion coefficient of the cylinder blocks 1 and 2 are different, the self-supplementing function of the seal is always secured. Therefore, the sealing performance does not change even if the temperature inside the compressor changes. Moreover, the rotary valves 27, 28 can be made of synthetic resin, and
The tapered structure of the sliding contact peripheral surfaces 27c and 28c also contributes to weight reduction of the compressor.

As shown in FIGS. 3 and 4, the rotary valve 2
A groove-shaped bypass passage 27d (28d) is formed in the tapered outer peripheral surface 27c (28c) of 7 (28). The outlet 29 of the suction passage 29 (30) is provided on the leading side of the bypass passage 27d (28d) in the rotational direction of the rotary valve.
Shortly after the b (30b) is closed by the taper inner peripheral surface S of the storage chamber, the first passage temporarily communicating with the conduction path 1b (2b)
A communication groove 27e (28e) is formed. Similarly, on the trailing side of the bypass passage 27d (28d) in the rotation direction of the rotary valve, the passage 29b (30b) is communicated with the passage 1b (2b) slightly before the outlet 29b (30b) is communicated with the passage 1b (2b).
A second communication groove 27f (28f) that is in temporary communication with is formed. The conduction path 1b (2b) is connected to the outer peripheral surface 15a of the piston 15 and the tapered outer peripheral surface 27c (28).
Shortly after the space becomes a closed space by c), the refrigerant gas in the space is guided through the bypass passage 27d (28d) into the trailing-side conduction passage 1b (2b) separated by one. (See FIGS. 3 and 5) One end of the rotary shaft 7 projects outward from the front housing 18, and the other end projects into the discharge chamber 24 on the rear housing 19 side. A discharge passage 37 is formed at the center of the rotary shaft 7. Discharge passage 3
7 is open to the discharge chamber 24. Front housing 1
A discharge port 38 is formed in the peripheral surface portion of the rotary shaft 7 surrounded by the discharge chamber 23 on the eighth side, and the discharge chamber 23 and the discharge passage 37 are connected by the discharge port 38. Therefore, the front and rear discharge chambers 23, 24 communicate with each other through the discharge passage 37, and the refrigerant gas in the discharge chamber 24 joins the discharge chamber 23 from the discharge passage 37. The discharge refrigerant gas in the discharge chamber 23 is discharged from the discharge passage 25 to the discharge refrigerant gas pipe line outside.

In the case of a flapper valve type suction valve, the lubricating oil increases the suction force between the suction valve and its close contact surface, and the suction valve delays the opening start timing of the suction valve. Due to this delay, the suction resistance due to the elastic resistance of the suction valve reduces the volumetric efficiency. However, when the rotary valves 27 and 28 that are forcedly rotated are used, there is no problem of the suction force due to the lubricating oil and the suction resistance due to the elastic resistance of the suction valve, and the pressures in the working chambers R, Ra, and Rb are the same in the swash plate chamber 11. If the suction pressure is slightly lower than the suction pressure of
It flows into a and Rb. Therefore, the rotary valves 27, 2
When 8 is adopted, the volumetric efficiency is significantly improved compared to when a flapper valve type suction valve is adopted.

Next, the operation of the piston type compressor constructed as described above will be described. In the state shown in FIG. 2, the uppermost double-headed piston 15 is at the top dead center position with respect to one cylinder bore 13 and is at the bottom dead center position with respect to the other cylinder bore 14. In such a piston arrangement state, the outlet 29b of the suction passage 29 is immediately before connecting to the communication passage 1b communicating with the working chamber Ra of the cylinder bore 13 as shown in FIG.
Although not shown, b is immediately before the end of communication with the conduction path 2b of the cylinder bore 14.

When the double-headed piston 15 enters the suction stroke in the cylinder bore 13 from the top dead center position to the bottom dead center position, the suction passage 29 communicates with the working chamber Ra of the cylinder bore 13. Due to this communication, the refrigerant gas in the swash plate chamber 11 passes through the suction passage 29 and the conduction passage 1b, and the cylinder bore 13
Is sucked into the working chamber Ra.

On the other hand, the double-headed piston 15 has the cylinder bore 1
4, when the compression stroke from the bottom dead center position to the top dead center position is entered, the suction passage 30 is blocked from communicating with the working chamber Rb of the cylinder bore 14. Due to this disconnection, the refrigerant gas in the working chamber Rb is discharged from the discharge port 4c into the discharge chamber 24 while pushing the discharge valve 32 away.

The suction and discharge of the refrigerant gas as described above are similarly performed in the working chambers R of the other cylinder bores 13, 14. FIG. 6 shows the rotation angle of the rotary valve 27 (rotary shaft 7), that is, the position of the piston 15 and the cylinder bore 13.
The relationship with the pressure Pa of the inner working chamber Ra is shown. With this graph, the compression operation when the cooling load is large and when it is small will be described.

The cooling load is large and the discharge pressure Pd of the compressor is large.
Is large (for example, 35 Kg / cm ² ), when the piston 15 moves from the top dead center to the bottom dead center, the compressed gas remaining in the working chamber Ra of the top volume re-expands. Therefore, the pressure Pa in the working chamber Ra (35 Kg / c
m ² ) drastically decreases as shown by the solid line G in FIG. 6, and when the rotary valve 27 rotates about 40 degrees, the piston 1
The outlet 1c of the conduction path 1b, which is closed by the outer peripheral surface 15a of No. 5, is opened. Therefore, the working chamber Ra and the swash plate chamber 11
Are communicated with each other through the suction passage 29 and the conduction passage 1b, the refrigerant gas is sucked into the working chamber Ra from the swash plate chamber 11, and the pressure Pa in the chamber Ra is equal to the suction pressure (for example, 2 Kg / c).
m ² ).

When the piston 15 moves to the bottom dead center and then moves toward the top dead center again, the rotary valve 27
The conduction path 1b is closed by the tapered outer peripheral surface 27c of
The refrigerant gas sucked into the working chamber Ra is compressed and
The pressure Pa in a rises. After that, when the piston 15 moves to an intermediate position between the bottom dead center and the top dead center (about 300 degrees at the rotation angle of the rotary shaft 7), the conduction path 1b is closed by the outer peripheral surface 15a of the piston 15 and The inside of the passage 1b becomes a closed space by the outer peripheral surfaces 27c and 15a. Therefore, the pressure Pn in the conduction path 1b is maintained at an intermediate pressure (for example, 12 Kg / cm ² ) as shown by the chain line H in FIG. or,
Shortly after the start of the closing of the conduction path 1b, the bypass path 2
While the first communication groove 27e of 7d passes through the leading-side closed conduction path 1b, it is temporarily communicated with the conduction path 1b. In synchronization with this, while the second communication groove 27f passes through another conduction path 1b on the trailing side, which is separated from the conduction path 1b on the leading side, it is temporarily communicated with the conduction path 1b. For this reason, the refrigerant gas having the intermediate pressure Pn in the leading-side communication passage 1b is not connected to the first communication groove 27e, the bypass passage 27d, and the second communication groove 2.
It is supplied into the working chamber Ra in the middle of the compression stroke through 7f and the trailing-side conduction path 1b, and the power is recovered. That is,
There is a portion where the pressure rises a little in the middle of the pressure curve shown by the solid line G in FIG. This is because the refrigerant gas in the preceding passage 1b is supplied into the working chamber Ra through the bypass passage 27d. As a result, the leading side conduction path 1b
As compared with the case where the confined refrigerant gas inside is directly returned to the swash plate chamber 11, the compression efficiency is improved, suction pulsation is suppressed, and vibration and noise can be suppressed.

On the other hand, when the pressure Pa in the working chamber Ra rises to the discharge pressure Pd as the piston 15 moves to the top dead center, the discharge valve 31 is pushed away and the compressed refrigerant gas is discharged into the discharge chamber 23. Is ejected. Even if the pressure Pa in the working chamber Ra rises, this high pressure causes the rotary valve 27
Does not act on the tapered outer peripheral surface 27c.

On the other hand, when the cooling load is small and the discharge pressure Pd of the compressor is low (for example, 15 Kg / cm ² ), the curve of the pressure Pa in the working chamber Ra due to the reciprocating movement of the piston 15 is a chain line J in FIG. As shown in. However, in this case as well, the pressure Pn of the conduction path 1b, which has become a closed space by both outer peripheral surfaces 27c and 15a, is maintained at an intermediate pressure (for example, 12 kg / cm ² ) as in the case where the cooling load is large, and a little later. The power is recovered through the first communication groove 27e, the bypass passage 27d, and the second communication groove 27f into the other communication passage 1b that communicates with the working chamber Ra in the middle of the compression stroke.

Therefore, the pressure acting on the tapered outer peripheral surface 27c of the rotary valve 27 is only the closing intermediate pressure Pn of the conduction path 1b regardless of the magnitude of the cooling load.
Therefore, the urging spring 3 takes into consideration only a small partial pressure for separating the rotary valve 27 from the taper inner peripheral surface S.
The elastic force of 5 may be set low in advance. By thus reducing the pressing force of the rotary valve 27 by the biasing spring 35, the rotational sliding friction of the taper outer peripheral surface 27c of the valve 27 with respect to the taper inner peripheral surface S of the housing chamber 1a is reduced to drive the compressor. The required power can be reduced.
Further, the sliding surface 27c of the rotary valve 27 can be prevented from being worn or bite, and the durability can be improved.

By the way, at the closing timing of the piston 15 for the passage 1b, the pressure in the closed passage 1b is set to the intermediate pressure P below the maximum discharge pressure Pd (35 kg / cm ² ).
The rotation angle (300 degrees) is not limited as long as it can be maintained at n.

The present invention is not limited to the above embodiment, but can be embodied as follows. (1) Although the outer peripheral surfaces of the rotary valves 27 and 28 are formed in a tapered shape in the above embodiment, they may be formed in a cylindrical shape. In this case, the intermediate pressure Pn in the closed conductive paths 1b and 2b acts on the cylindrical outer peripheral surface. Therefore, the force with which the outer peripheral surfaces of the rotary valves 27 and 28 are locally pressed against the cylindrical inner peripheral surface of the accommodation hole is reduced. Therefore,
It is possible to reduce the rotational sliding friction of the sliding surface to prevent power loss, and to suppress the sliding surface from being worn or bite.
The other configurations, operations, and effects are the same as those in the above-described embodiment.

(2) In the above embodiment, the rotary valve 2
Bypass passages 27d and 28d were formed on the tapered outer peripheral surfaces 27c and 28c of Nos. 7 and 28, respectively.
To be formed in.

(3) In the above embodiment, the double-headed swash plate type piston compressor is embodied, but it should be embodied in the swing swash plate type variable displacement piston compressor.

[0047]

As described above in detail, according to the present invention, the position of the cylinder bore side outlet of the passage is set to the position where the piston is closed by the outer peripheral surface of the piston before moving to the top dead center. Further, in the rotary valve, the conduction path is guided by the outer peripheral surface of the piston and the outer peripheral surface of the rotary valve to form a space, and the refrigerant gas in the space is guided into the communication path communicating with the working chamber in the middle of compression. The formation of the bypass passage has the following effects.

(1) Even if the discharge pressure fluctuates, the pressure in the closed communication path that acts on the outer peripheral surface of the rotary valve is held at an intermediate pressure between the suction pressure and the discharge pressure, and the outer peripheral surface of the rotary valve is Suppresses the pressure acting on. The rotary sliding friction between the outer peripheral surface of the rotary valve and the inner peripheral surface of the storage chamber, which is in sliding contact with the outer peripheral surface of the rotary valve, is suppressed to reduce power loss, and wear and scratching of the sliding surface are suppressed to improve durability. Can be improved.

(2) The power of the intermediate pressure refrigerant gas in the closed passage is recovered to improve the compression efficiency, and the refrigerant gas in the passage is not returned to the suction chamber to suppress the suction pulsation. It is possible to suppress the vibration and noise of the compressor.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts showing an embodiment of a compressor of the present invention.

FIG. 2 is a cross-sectional view showing the entire compressor.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a perspective view of a rotary valve.

FIG. 5 is a development view of a rotary valve.

FIG. 6 is a graph showing the relationship between the rotation angle of the rotary valve and the pressure of the working chamber in the cylinder bore.

[Explanation of symbols]

1, 2 ... Cylinder block, 1a, 2a ... Storage chamber, 1
b, 2b ... Conduction passage, 1c, 2c ... Cylinder bore side outlet of the conduction passage, 7 ... Rotating shaft, 11 ... Swash plate chamber as suction chamber, 1
3, 14 ... Cylinder bore, 15 ... Piston, 15a ... Outer peripheral surface, 23, 24 ... Discharge chamber, 27, 28 ... Rotary valve, 27c, 28c ... Tapered outer peripheral surface, 27d, 28d ...
Bypass passage, 29, 30 ... Intake passage, 29b, 30b
... Outlet of suction passage, 35, 36 ... Energizing spring, S ... Tapered inner peripheral surface, R, Ra, Rb ... Working chamber, Pn ... Pressure in conduction passages 1b, 2b which are closed spaces.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor, Koichi Ito, 2-chome, Toyota-cho, Kariya city, Aichi stock company Toyota Industries Corp.

Claims (1)

[Claims] 1. A refrigerant gas is drawn from a suction chamber by accommodating a piston in a plurality of cylinder bores arranged so as to surround a rotary shaft with respect to a cylinder block, and reciprocatingly moving the piston in association with rotation of the rotary shaft. A piston-type compressor configured to suck the compressed refrigerant gas into the discharge chamber and discharge the compressed refrigerant gas to the discharge chamber by means of the piston, between the cylinder bore and the rotating shaft with respect to the cylinder block. A storage chamber having an inner peripheral surface is provided so as to be located in the storage chamber, and the storage chamber accommodates a rotary valve having an outer peripheral surface that is slidably fitted to the inner peripheral surface. To the rotary valve so as to be rotatable in synchronism with the shaft, and a rotary valve for sucking the refrigerant gas from the suction chamber to the working chamber during the suction stroke. Before the piston moves to the top dead center, the inlet passage is formed, a conduction path is formed between the accommodation chamber and the working chamber to connect the two chambers to each other, and the position of the cylinder bore side outlet of the conduction path is set to the top dead center. Is set to a position closed by the outer peripheral surface of the piston, and further, in the rotary valve, the conduction path is a space enclosed by the outer peripheral surface of the piston and the outer peripheral surface of the rotary valve, and the refrigerant in the space is closed. A refrigerant gas suction structure in a piston type compressor in which a bypass passage for guiding gas into a communication passage communicating with a working chamber being compressed is formed.