JP3082480B2 - Refrigerant gas suction structure in piston type 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 gas in a piston type compressor in which a piston is accommodated in a plurality of cylinder bores arranged around a rotary shaft and the piston reciprocates in conjunction with the rotation of the rotary shaft. It relates to a suction structure.

[0002]

2. Description of the Related Art In a conventional piston compressor (for example, see Japanese Patent Application Laid-Open No. 3-92587), a suction port between a working chamber and a suction chamber defined in a cylinder bore by a piston is provided by a flapper valve in the working chamber. It can 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.

The opening and closing operation of the flapper valve is based on the pressure difference between the working chamber and the suction chamber. If the pressure in the suction chamber is higher than the pressure in the working chamber, the flapper valve bends and opens 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 to the bottom dead center.

[0004]

The 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, the opening of the flapper valve is delayed. Lubricating oil is mixed in the refrigerant gas for lubricating the inside of the compressor, and this lubricating oil is sent together with the refrigerant gas to a required lubricating portion in the compressor. This lubricating oil can enter anywhere in the refrigerant gas flow area, and the lubricating oil also adheres between the flapper valve closing the suction port and its close contact surface. This attached lubricating oil increases the close contact force between the close contact surface and the flapper valve, further delaying the start of the flapper valve's bending deformation. Such a delay in starting the bending deformation causes a decrease in the amount of refrigerant gas flowing into the working chamber, that is, a decrease in volumetric efficiency. Even when the flapper valve is open, the elastic resistance of the flapper valve acts as a suction resistance, so that the refrigerant gas inflow decreases and the compression efficiency decreases.

Therefore, the present applicant has proposed a double-headed piston type compressor capable of improving the compression efficiency.
In this compressor, for example, a swash plate is fitted and fixed on a rotating shaft, and a double-headed piston is moored to the swash plate via a shoe. A rotary valve is fitted on the rotary shaft so as to be synchronously rotatable so as to be located in a storage chamber formed at the center of the cylinder block.
Refrigerant gas is introduced from the swash plate chamber into the working chamber during the suction stroke defined in the cylinder bore through the suction passage provided in the rotary valve and the conduction path formed in the cylinder block by the reciprocating motion of the double-headed piston in the cylinder bore, The refrigerant gas compressed by the cylinder bore is discharged from the discharge hole to the discharge chamber.

When the new compressor is started in the maximum capacity state, the rotary valve rotates the rotary valve at a predetermined position by the rotating shaft, and the refrigerant gas sucked from the suction chamber passes through the suction passage and the passage of the rotary valve during the suction stroke. Is sucked into the working chamber, and the sucked gas is compressed in the working chamber and then discharged to the discharge chamber. Therefore, when the compressor is started when the liquid refrigerant remains in the working chamber in the cylinder bore, the compression operation starts in a large capacity state, so that the liquid compression occurs and the torque acting on the rotating shaft increases, and In the worst case, an abnormal sound is generated, and the compressor is damaged.

The applicant of the present invention has proposed a swash plate type variable displacement piston type compressor incorporating a rotary valve and having a maximum capacity start-up (for example, see Japanese Patent Application No. 4-262371). The same problem as the above-described liquid compression also occurs in the machine.

The present invention relates to a large capacity start-up type piston compressor, which can reliably prevent liquid compression at the time of start-up, suppress occurrence of abnormal noise, and improve durability. It is an object of the present invention to provide a refrigerant gas suction structure in a type compressor.

[0009]

According to the present invention, there is provided a piston type compression system in which a piston is accommodated in a plurality of cylinder bores arranged around a rotary shaft and the piston reciprocates in conjunction with the rotation of the rotary shaft. In the machine, a valve accommodating chamber communicated with a working chamber defined by a piston in a cylinder bore through a conduction path is provided, and a rotary valve for suctioning refrigerant gas is rotated in synchronization with the reciprocating motion of the piston in the accommodating chamber. The rotary valve accommodates refrigerant gas from the suction chamber into the working chamber in correspondence with the conduction path communicating with the working chamber during the suction stroke. A suction passage and a suction guide groove for introduction are formed, and between each of the working chambers or each of the working chambers, between the outer peripheral surface of the rotary valve and the inner peripheral surface of the valve accommodating chamber. A communication path capable of communicating with the chamber is provided, and the rotary valve is constantly urged by an urging member to a position where the communication path operates, and further, the rotary valve is moved from a position where the communication path operates to the suction guide. A rotary valve position switching mechanism is provided for switching the groove to a suction operation position corresponding to the conduction path.

[0010]

According to the present invention, when the piston type compressor is stopped, the rotary valve is switched and held by the urging member to a position in which the working chambers in the cylinder bore or between the working chamber and the suction chamber communicate with each other through a communication passage. I have. When the rotating shaft is rotated in this state and the piston is reciprocated in the cylinder bore, the plurality of working chambers are communicated with each other, so that the compression operation is not substantially performed by the reciprocating motion of the piston. Therefore, even if liquid refrigerant remains in the working chamber in the cylinder bore, compression is not performed, shocks at the time of starting the compressor are alleviated, abnormal noise is prevented, and compressor damage is prevented. Is done.

When the compressor is started and a predetermined time has elapsed, the liquid refrigerant in the working chamber in the cylinder bore is vaporized by the reciprocating operation of the piston in a no-load state. Therefore, when the rotary valve is moved to the operating position where the refrigerant gas is sucked from the suction chamber into the working chamber by the rotary valve position switching mechanism, the reciprocating motion of the piston causes the suction passage from the suction chamber to the suction passage in the rotary valve to move. Refrigerant gas is sucked into the working chamber during the suction stroke through the suction guide groove and the conduction path. When the piston shifts to the compression step, the conduction path is closed by the outer peripheral surface of the rotary valve, the refrigerant gas is compressed in the working chamber, and the compressed refrigerant gas is discharged to the discharge chamber.

[0012]

FIG. 1 shows an embodiment of the present invention.
This will be described with reference to FIG. A front housing 5 and a rear housing 6 are joined to the front and rear end surfaces of the pair of front and rear cylinder blocks 1 and 2 via valve plates 3 and 4, and are fixed to each other by a plurality of bolts 7 and 8. A rotating shaft 9 is rotatably supported at the center of the front housing 5 and the rear housing 6 by conical roller bearings 10 and 11. A swash plate 12 is fitted and fixed to the outer peripheral surface of the rotating shaft 9 and is housed in a swash plate chamber 13 as a suction chamber formed at a joint portion between the cylinder blocks 1 and 2. Further, a suction port 14 for sucking refrigerant gas from an external refrigerant pipe (not shown) into the swash plate chamber 13 is formed in the outer peripheral portion of the cylinder block 1. A plurality of (5 in this embodiment) cylinder bores 15, 16 are formed in the cylinder blocks 1, 2.
Inside, a double-headed piston 17 is moored to the slope of the swash plate 12 via a pair of front and rear shoes 18. The rotating shaft 9
Rotary valves 31 and 32 described in detail later
The refrigerant gas in the swash plate chamber 13 passes through the cylinder bores 15,
The working chamber R is sucked into the working chamber 16.

Discharge chambers 19, 20 are formed in the front housing 5 and the rear housing 6, and can communicate with the working chamber R in the cylinder bores 15, 16 by discharge holes 3a, 4a formed in the valve plates 3, 4. ing. Discharge valves 21 and 22 for opening and closing discharge holes 3a and 4a are sandwiched and fixed between the valve plate 3 (4) and the front housing 5 (rear housing 6) together with the retainers 23 and 24 in the valve plates 3 and 4. Have been.

A discharge passage 25 is formed at the center of the rotary shaft 9, and communicates with the rear discharge chamber 20 and the discharge passage 25 through a communication passage 26 formed in the rear housing 6. The rotary shaft 9 is provided with a communication hole 27 for communicating the discharge passage 25 with the accommodation chamber 5a of the conical roller bearing 10. The storage chamber 5 a is communicated with the discharge chamber 19 on the front side by a communication passage 28. Therefore, the discharge chambers 19 and 20 on the front and rear sides are connected to the discharge passage 25,
The communication passages 26 and 28 and the communication hole 27 communicate with each other. Further, the discharge chamber 1 is provided in the front housing 5.
A discharge port 29 for discharging the refrigerant gas No. 9 to an external refrigerant pipe (not shown) is formed. The front housing 5
Is provided with a shaft seal mechanism 30 in the center hole.

Next, a description will be given of a rotary valve type refrigerant gas suction structure which is a main part of the present invention. Valve accommodating chambers 1a and 2a for accommodating front and rear rotary valves 31 and 32 are formed around the rotation shaft 9 at the center of the cylinder blocks 1 and 2.
The rotary valves 31 and 32 are fitted to the spline portions 9 a and 9 b provided on the rotary shaft 9 so as to be movable in the axial direction of the rotary shaft 9 and to be synchronously rotatable. Conduction paths 1b and 2b are formed in the cylinder blocks 1 and 2 to communicate the working chamber R in the cylinder bore and the valve chambers 1a and 2a, respectively. Suction passages 33, 34 are provided on the inner peripheral surfaces of the rotary valves 31, 32.
Are formed, and the outer ends of the suction passages 33 and 34 communicate with the swash plate chamber 13. Further, suction guide grooves 35, 36 connected to the inner ends of the suction passages 33, 34 are formed in the outer peripheral surfaces of the rotary valves 31, 32 in the circumferential direction as shown in FIG. And the working chamber R during the suction stroke
Path 1b (2b) communicating with the suction guide groove 35
In the state corresponding to (36), the suction passage 3
3 (34), suction guide groove 35 (36) and conduction path 1b
The refrigerant gas can be sucked into the working chamber R through (2b).

On the outer peripheral surfaces of the rotary valves 31 and 32, annular grooves 37 and 38 as communication paths are formed at predetermined distances from the suction guide grooves 35 and 36. The two rotary valves 31 (32) are springs 39 (40) as biasing members interposed between the swash plate 12 and the boss.
The annular groove 37 (38) and the conductive path 1b (2b)
And the suction guide groove 35 (36) is connected to the conduction path 1b.
It is biased to a position that does not correspond to (2b). Front-side and rear-side pressure-sensitive chambers 41 and 42 are defined by the housing chambers 1a and 2a of the cylinder blocks 1 and 2 and the inner end faces of the rotary valves 31 and 32, respectively. The two pressure-sensitive chambers 41 and 42 are formed with control passages 43 and 4 formed in the valve plates 3 and 4 and the cylinder blocks 1 and 2, respectively.
4 communicates with the discharge chambers 19 and 20.

In this embodiment, the valve positions are switched to switch the rotary valves 31 and 32 from the inoperative position where refrigerant gas cannot be sucked to the operating position by the pressure-sensitive chambers 41 and 42, the control passages 43 and 44 and the springs 39 and 40. The mechanism K is constituted.

Next, the operation of the piston type compressor configured as described above will be described. FIG. 1 shows a stopped state of the compressor. In this state, the pressure of the discharge chambers 19 and 20 and
Since the pressures in the pressure sensing chambers 41 and 42 are equal, the rotary valves 31 and 32 are held at the inoperative positions by the springs 39 and 40, respectively.

In this state, when the rotating shaft 9 of the compressor is rotated by an electromagnetic clutch (not shown), the double-ended piston 17 is reciprocated in the cylinder bores 15 and 16 by the swash plate 12. When the compressor is started, the working chambers R to R in the front cylinder bore 15 are communicated with each other by an annular groove 37 provided in the rotary valve 31, and the operation in the rear cylinder bore 16 is provided by an annular groove 38 provided in the rotary valve 32. Since the chambers R to R are communicated with each other, the compression operation is not substantially performed. Therefore, even if the compressor is started in a state where the liquid refrigerant remains in the working chambers R to R in the cylinder bores, the liquid compression is prevented, the starting shock is reduced, and the generation of abnormal noise is suppressed. Therefore, it is possible to suppress the breakage of the drive mechanism of the compressor and improve the durability.

When the compressor is started, the compression operation is not substantially performed by the reciprocation of the piston 17, but the liquid refrigerant remaining in the working chamber R is vaporized by the reciprocation of the piston. In addition, the conductive paths 1b and 2b, the annular grooves 37 and 3
8 to some extent, the working chamber R in the cylinder bore
Then, the refrigerant gas is compressed. Therefore, the discharge holes 3a, 4
a, the discharge valves 21 and 22 are pushed out to discharge chambers 19 and 20.
A small amount of the refrigerant gas compressed is gradually discharged. When the pressure in the discharge chambers 19 and 20 gradually increases, refrigerant gas is supplied from the control passages 43 and 44 to the pressure-sensitive chambers 41 and 42, and when the pressure in the pressure-sensitive chambers 41 and 42 becomes equal to or higher than the set pressure, The rotary valves 31 and 32 are moved along the splines 9a and 9b on the rotating shaft 9 toward the swash plate 12 against the urging forces of the springs 39 and 40. And, the suction guide grooves 35, 36 of both rotary valves 31, 32 are
When gradually moved to a position corresponding to the conduction paths 1b and 2b, the refrigerant gas in the swash plate chamber 13 is drawn into the suction paths 33 and 34,
Suction is gradually sucked from the suction guide grooves 35 and 36 into the working chamber R in the cylinder bore during the suction process through the conduction paths 1b and 2b. Further, the sucked refrigerant gas is compressed by the piston 17 and discharged to the discharge chambers 19 and 20 from the discharge holes 3a and 4a, and thereafter, shifts to a steady compression operation.

When the electromagnetic clutch is turned off and the compressor is stopped, the pressure in the discharge chambers 19, 20 and the pressure-sensitive chambers 41,
When the pressure of 42 decreases and this pressure becomes equivalent to the suction pressure,
The rotary valves 31 and 32 are returned from the suction operation position to the inoperative position by the springs 39 and 40, that is, the annular grooves 37 and 38 are returned to the positions corresponding to the conduction paths 1b and 2b, thereby alleviating the shock at the time of starting the next compressor. Be provided.

The present invention is not limited to the above embodiment, but can be embodied as follows. (1) In the above-described embodiment, the annular grooves 37 and 38 that can communicate the respective cylinder bores 15 and 16 with each other are formed in the rotary valve 3.
1 and 32, but instead of this groove, the swash plate chamber 13 and each of the conductive paths 1b and 2b are configured to communicate with each other.

(2) In the above-described embodiment, the position switching mechanism K of the rotary valve is constituted by the pressure-sensitive chambers 41 and 42 and the control passages 43 and 44. Instead, a predetermined time has elapsed after the start of the compressor. At this time, the position of the rotary valves 31, 32 is switched by an operating rod of an electromagnetic solenoid (not shown).

(3) In the above embodiment, the present invention is embodied as a fixed displacement double head piston type swash plate type compressor. However, the present invention is embodied as a maximum starting type swinging swash plate type variable displacement piston compressor.

[0025]

As described in detail above, the present invention can prevent the compression of the liquid refrigerant at the time of starting the compressor, alleviate the starting shock, reduce abnormal noise, and improve the piston and swash plate. And the like, the load acting on the drive mechanism can be reduced, the durability reliability can be improved, and the mechanical strength of the components can be reduced to reduce the size and weight of the compressor.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment in which the present invention is embodied in a double-headed piston type swash plate type compressor.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a partially enlarged cross-sectional view of the vicinity of a rotary valve held at a suction operation position.

FIG. 4 is a sectional view taken along line BB of FIG. 3;

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

[Explanation of symbols]

1, 2 cylinder block, 1a, 2a valve accommodation chamber, 1b, 2b conduction path, 5 front housing, 6
Rear housing, 9 rotating shaft, 12 swash plate, 13 swash plate chamber as suction chamber, 15, 16 cylinder bore, 17
Double-headed piston, 19, 20 discharge chamber, 31, 32 rotary valve, 33, 34 suction passage, 35, 36
Suction guide groove, 37, 38 annular groove as communication passage, 3
9, 40 Spring as a biasing member, 41, 42 Pressure sensing chamber, 43, 44 Control passage, R working chamber, K Rotary valve position switching mechanism.

Continued on the front page (72) Inventor Kazuaki Iwama 2-1-1, Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (58) Field surveyed (Int. Cl. ⁷ , DB name) F04B 27/08

Claims (1)

(57) [Claims] 1. A piston type compressor in which a piston is housed in a plurality of cylinder bores arranged around a rotation shaft and the piston reciprocates in conjunction with rotation of the rotation shaft, wherein the piston is partitioned into the cylinder bore by the piston. A valve accommodating chamber that communicates with a working chamber through a conduction path, wherein a rotary valve for suctioning refrigerant gas is rotatable in synchronization with reciprocation of a piston, and is axially movable in the accommodating chamber. A suction passage and a suction guide groove for introducing refrigerant gas from the suction chamber into the working chamber corresponding to the conduction path communicating with the working chamber during the suction stroke. Forming, between the outer peripheral surface of the rotary valve and the inner peripheral surface of the valve storage chamber, a communication passage capable of communicating the respective working chambers or the respective working chambers and the suction chamber is provided,
The rotary valve is constantly urged by an urging member to a position where the communication passage operates, and further, the rotary valve is moved from a position where the communication passage operates to a suction operation position where the suction guide groove corresponds to the conduction passage. Refrigerant gas suction structure in a piston type compressor provided with a rotary valve position switching mechanism for switching to a.