JPH0759942B2 - Variable capacity compressor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is mainly used in vehicle air-conditioning systems, for example,
The present invention relates to a piston type variable displacement compressor such as a swash plate type compressor or a wobble compressor.

(Prior Art) Conventionally, there is a double-headed piston type swash plate type variable displacement compressor as shown in FIG. This supports the spool 54 in the discharge chamber 18 of the rear housing 6 so as to be capable of reciprocating,
The spool 54 supports a discharge valve 55 and a retainer 56. And when you want to reduce the capacity, the discharge flange 57
The first solenoid valve 58 communicating with the swash plate chamber 8 is closed, and the second solenoid valve 59 communicating with the swash plate chamber 8 is opened to apply a low suction pressure to the back pressure chamber 60 of the spool 54, and the discharge is always performed by the spring 61. The valve 55, together with the retainer 56, is levitated and held in an inoperative position where compression is disabled to disable the compression operation on the rear side, and the reverse flow of the gas compressed on the front side to the rear side is
It was prevented by a check valve 63 provided in the discharge passage 62 on the rear side. Further, when it is desired to increase the capacity, the first solenoid valve 58 is opened and the second solenoid valve 59 is closed to apply a high discharge pressure to the back pressure chamber 60 of the spool 54 so that the discharge valve 55 is closed. There was one that was held in a normal operating position in contact with No. 4 to enable the compression operation on the rear side.

(Problems to be Solved by the Invention) However, the conventional variable displacement compressor requires the check valve 63 and the first and second solenoid valves 58 and 59, which makes the structure complicated, the cost is high, and the check valve is Since the valve is incorporated, the discharge flange 57 becomes large and the compressor becomes large. Also, 100
The discharge passage 62 on the rear side when the capacity decreases from 50% to 50%
The high-temperature, high-pressure discharge gas inside temporarily returns to the suction side, reducing the compression efficiency, and the gas sucked into the rear-side cylinder bore 11, that is, the compression chamber during 50% operation, is sucked into the suction hole 3
There is a problem in that the gas that is sucked from both the 0 and the discharge holes 32, but discharged is only discharged through the discharge holes 32, so that gas escape is poor and thus power loss occurs during high-speed operation.

Configuration of the Invention (Means for Solving the Problems) In order to solve the above problems, the present invention provides a piston type compressor in which a predetermined pressure such as atmospheric pressure, sealing pressure or discharge pressure is applied to a suction chamber. A pressure chamber is formed separately from the suction chamber, and a partition wall is provided with a movable support member that is reciprocally moved toward the suction valve by a pressure difference between the pressure of the suction chamber and the pressure of the predetermined pressure chamber. The movable supporting member is provided with a valve pushing member for switching a part of the intake valve between a normal operating position and a non-operating position where the suction valve is floated and held on the piston side. Is provided with a valve displacement permitting means for permitting displacement of the intake valve to the normal position when the piston is moved to the top dead center, and further, a valve pushing member is provided on the movable support member in response to pressure variation in the intake chamber. Means of engaging a biasing means for moving back and forth It has adopted.

(Operation) The present invention operates as follows by adopting the above means.

When the cooling load in the passenger compartment is large and the pressure of the suction chamber is high, the pressure of the predetermined pressure chamber acting on the movable support member, the force of the biasing means, and the pressure of the suction chamber push the movable support member. A large capacity operation is performed by moving the moving member in a direction away from the intake valve. Also, the cooling load in the passenger compartment is small,
When the pressure of the suction chamber is low, the pressure of the predetermined pressure chamber acting on the movable support member, the force of the biasing means, and the pressure of the suction chamber move the movable support member together with the valve pushing member to the suction valve side. As a result, the intake valve is held in the compression invalid position, and the small capacity operation is performed. During this small-capacity operation, the intake valve in the floating position is pushed toward the valve plate each time the piston moves to the top dead center, but this is allowed by the valve displacement allowing means.

(Embodiment) An embodiment in which the present invention is embodied in a double-headed swash plate compressor will be described below with reference to FIGS. 1 to 5. This compressor has five cylinders on one side, that is, 10 cylinders, and both ends of cylinder blocks 1 and 2 which are opposed to each other in the figure are joined to each other through valve plates 3 and 4 to form a front housing 5 and a rear housing 5. , 6
Closed by means of a suitable number of bolts 7. A swash plate chamber 8 is formed at the joining portion of the cylinder blocks 1 and 2, and the cylinder blocks 1 and 2 are formed there.
A swash plate 10 that is inclined and fixed to a drive shaft 9 that penetrates through shaft holes 1a and 2a that are provided at the center of 2 is housed. The cylinder blocks 1 and 2 are provided with five sets of cylinder bores 11 that are parallel to the drive shaft 9 and that form compression chambers at radial positions around the drive shaft 9, and the pistons are fitted into the cylinder bores 11. 12 is moored to the swash plate 10 via a bearing device including a ball 13 and a shoe 14, and the piston 12 can reciprocate in the cylinder bore 11 by the rotational force of the swash plate 10.

An annular discharge chamber 15 is formed on the center side of the front housing 5, and a substantially annular suction chamber 16 is formed on the outer peripheral side so as to surround the discharge chamber 15. A cylindrical suction chamber 17 is formed on the center side of the rear housing 6, and an annular discharge chamber 18 is formed on the outer peripheral side so as to surround the suction chamber 17. The suction chamber 16 on the front side is communicated with the swash plate chamber 8 by a suction passage 19 which also serves as a through hole for the bolt 7, and the suction chamber 17 on the rear side is provided between the bores of the cylinder block 2 and the valve plate 4. The suction passage 20 communicates with the swash plate chamber 8, and the swash plate chamber 8 and the cylinder blocks 1, 2
Is in communication with a suction flange 21 (see FIG. 3) mounted near the mating surface of the.

In addition, at one position between the bores in the cylinder blocks 1 and 2, a fifth area is provided from the contact surface with the valve plates 3 and 4 to the mating surface.
As shown in the figure, the discharge passages 22 and 23 are bored, and one end of each of the discharge passages 22 and 23 is connected to a discharge flange 24 attached near the mating surfaces of the cylinder blocks 1 and 2 and a communication hole 25, respectively. The discharge chambers 15 and 18 are communicated with each other through through holes 27 and 28 which are communicated with each other through the valve plates 3 and 4 at the other end.
However, in the discharge chamber 15 on the front side, a communicating portion with the discharge passage 22 is appropriately bulged to the outer peripheral side.

Suction holes 29 and 30 and discharge holes 31 and 32 are formed through the valve plates 3 and 4, respectively, and the cylinder bore 11 is inserted through these holes.
6, 17 and the discharge chambers 15, 18 are communicated with the suction holes 29, 30, and the discharge holes 31, 32, respectively.
And discharge valves 35, 36 are provided. Rear intake valves 3
4 is formed in a tongue shape as shown in FIG. 4, and a through hole 34a corresponding to the discharge hole 32 is formed at the base end portion thereof. Further, the amount of deformation of the discharge valves 35, 36 is restricted by the valve retainers 37, 38, and on the front side, the discharge valves 35, 36 are fixed by being sandwiched between the valve plate 3 and the front housing 5.
On the rear side, it is fastened and fixed to the valve plate 4 together with the valve retainer 38 by bolts 39.

Next, the suction valve provided in the suction chamber 17 on the rear side is provided.
A capacity control mechanism for controlling the compression capacity by switching 34 between the normal operation position for effectively performing the compression operation and the non-operation position for invalidating the compression operation levitated (separated) from the valve plate 4 will be described. To do.

A mounting hole 6a is formed in the center of the rear housing 6, and a cover plate 40 is fixed by a bolt 41 so as to cover the mounting hole 6a. A base end of a bellows 42 is attached to the cover plate 40, and a movable support member 43 is attached to a tip end portion of the bellows 42. The lid plate 40 having the ventilation holes 40a, the bellows 42, and the movable support member 43 define an atmosphere chamber 44 as a predetermined pressure chamber that communicates with the atmosphere independently of the suction chamber 17. The movable support member 43 has a plurality of pushing pieces 45a which are bent and formed at right angles so as to push the suction valve 34 by entering the suction holes 30 into the suction holes 30. A valve pushing plate 45 as a moving member is attached by a bolt 46. The valve pushing plate 45 is made of an elastic material, is elastically deformable in the front-rear direction, and has a function as a valve displacement allowing means. It should be noted that the valve plate 4 on the rear side has a passage that connects the shaft hole 2a of the cylinder block 2 and the suction chamber 17 to each other.
4a is formed so that the bolt 46 can move in and out.

A coil spring 47 as an urging means is interposed between the cover plate 40 and the movable support member 43, and the valve pushing plate 45 is always floated from the front side, that is, the intake valve 34 from the valve plate 4 for compression operation. Is urged in the direction to hold it in the inoperative position to invalidate.

Next, regarding the variable capacity compressor configured as described above,
The operation will be described.

Now, in FIG. 1, the temperature inside the vehicle compartment is high and the cooling load is large, and the compressor is operating at 100% capacity.
In this state, the pressure in the evaporator is high, the suction pressure is high, the pressure in the rear suction chamber 17 becomes larger than the combined force of the coil spring 47 and the atmospheric pressure, and the valve pushing plate 45 separates from the valve plate 4. It shows the state in which the suction valve 34 is in the normal operating position and the rear side compression operation is effectively performed in addition to the front side compression operation.

When the operation of the compressor is continued, the cooling load decreases, and the pressure inside the evaporator decreases, the pressure in the suction chamber 17 also decreases,
The combined force of the spring force of the coil spring 47 and the atmospheric pressure becomes larger than the suction pressure on the rear side, the valve pushing plate 45 is moved to the front side, and each pushing piece 45a of the valve pushing plate 45 moves to each suction valve. 34 is opened all at once. As a result, the five cylinders on the rear side are in a compression disabled state, and thereafter they are operated at 50% capacity.

In the 50% capacity operation shown in FIG. 6, when the piston 12 is moved to the top dead center, the intake valve 34 is temporarily pressed toward the valve plate 4 side, which is due to the elasticity of the valve pressing plate 45. Allowed by deformation.

By the way, the compressor has changed from 50% capacity to 100% capacity
When switching from% volume to 50% volume, there is a condition in which suction valve 34 is slightly pushed open. At this time, the cylinder bore
The gas compressed halfway in 11 is not blown back to the suction side. This is because the pressure in the cylinder bore 11 is
v, the suction pressure is Ps, and the pressure receiving area of the suction valve 34 is S,
When the pressure Pv rises, the force (Pv
This is because -Ps) -S overcomes the force of the valve pushing plate 45 and closes the intake valve 34.

The present invention can also be embodied as follows.

(1) The length of each pushing piece 45a of the valve pushing plate 45 is set to be 5 different, and the capacity is changed according to the change of the cooling load.
100% 90% 80% 70% 60% 50%,
Change gradually.

In this other example, the shock at the time of capacity switching can be reduced, the outlet temperature fluctuation of the evaporator can be made gentle, and further,
The capacity can be controlled in small steps corresponding to the cooling load.

(2) Providing the pushing piece 45a corresponding to, for example, only four of the five suction valves 34. Pushing piece 4 like this
By increasing or decreasing the number of 5a, variable capacity compressors with different capacity settings can be manufactured.

(3) Use as a compressor of a vehicle air conditioner in which an evaporation pressure adjusting valve (not shown) is arranged in the middle of a suction pipe line connecting the evaporator and the compressor.

(4) As shown in FIG. 7, a bottomed cylindrical partition wall 6b is formed inside the rear housing 6, a spool 49 as a movable support member is housed in the partition wall 6b, and the valve pushing operation is performed on the spool 49. The plate 45 is fixed by bolts 46. On the other hand, the back pressure chamber 50 as a predetermined pressure chamber formed on the back side of the spool 49 is communicated with the discharge chamber 18 on the rear side by the communication passage 51 provided in the housing 6, and the discharge pressure is applied to the back side of the spool 49 during operation. I am trying to work. Further, the valve pushing plate 45 and the passage 4a of the valve plate 4
A coil spring 47 'as an urging means is interposed between the bottomed cylindrical spring receiver 52 fitted in. Reference numeral 53 is a detent pin that allows only the back-and-forth movement of the valve pushing plate 45.

In the case of this another example, when the cooling load is large, the combined pressure of the suction pressure and the spring 47 overcomes the discharge pressure acting on the back surface of the spool 49, and is separated from the valve plate 4, and the rear side compression is effectively performed. On the contrary, when the cooling load decreases and the suction pressure decreases, the valve pushing plate is generated by the discharge pressure acting on the back surface of the spool 49.
45 moves forward and compression on the rear side is disabled.

(5) The capacity control mechanism may be provided not only on the rear side but also on the front side or only on the front side.

(6) In the embodiment shown in FIG. 1, the vent hole 40 of the lid plate 40
By omitting a, the atmosphere chamber 44 should be sealed and used as a predetermined pressure chamber.

(7) Other than the swash plate compressor, for example, embodying in a reciprocating compressor having a piston such as a wobble compressor.

EFFECTS OF THE INVENTION As described in detail above, since the present invention does not require a check valve and a solenoid valve, the structure can be simplified and the cost can be reduced. The compressor can be downsized. Further, when the capacity is switched, high-temperature and high-pressure refrigerant gas on the discharge chamber side is prevented from returning to the suction chamber side to improve compression efficiency.
Since the gas in the suction chamber and the gas in the compression chamber are alternately moved through the suction holes, the gas escape is improved and the power loss during high-speed operation can be reduced.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a central portion in a low capacity state in which the present invention is embodied in a swash plate type variable displacement compressor, FIG. 2 is a longitudinal sectional view of a central portion in a full capacity state, and FIG. AA line enlarged sectional view, FIG. 4 is an enlarged sectional view taken along the line BB of FIG. 1, FIG. 5 is a longitudinal sectional view near the discharge flange, FIG. 6 is an enlarged sectional view of a main part, and FIG. FIG. 8 is a vertical sectional view of a central portion in a full capacity state showing another example of the present invention, and FIG. 8 is a vertical sectional view of a central portion in a low capacity state showing a conventional swash plate type variable displacement compressor. 1,2 …… Cylinder block, 3,4 …… Valve plate, 5 …… Front housing, 6 …… Rear housing, 8 …… Swash plate chamber,
9 ... Drive shaft, 10 ... Swash plate, 11 ... Cylinder bore, 12 ...
… Piston, 15,18 …… Discharge chamber, 16,17 …… Suction chamber, 29,3
0 …… Suction port, 31,32 …… Discharge port, 33,34 …… Suction valve, 35,
36 ... Discharge valve, 40 ... Lid plate, 40a ... Vent hole, 42 ... Bellows, 43 ... Movable support member, 44 ... Atmosphere chamber as a predetermined pressure chamber, 45 ... As valve pushing member Valve push plate, 45a ……
Pushing piece, 47 ... Coil spring as biasing means, 49 ... Spool as movable supporting member, 50 ... Back pressure chamber as predetermined pressure chamber, 51 ... Communication passage.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuichi Sugizono 2-chome Toyota-cho, Kariya city, Aichi Prefecture Toyota Industries Corporation (56) References JP 59-200084 (JP, A) Sho 59-30233 (JP, Y2)

Claims (3)

[Claims] 1. A suction chamber and a discharge chamber are provided in a housing, and a piston is reciprocally housed in a plurality of cylinder bores.
Refrigerant gas is sucked into the compression chamber from the suction chamber through the plurality of suction holes and the plurality of suction valves, and the compressed gas is discharged to the discharge chamber through the plurality of discharge holes and the plurality of discharge valves. In the piston type compressor described above, a predetermined pressure chamber for applying a predetermined pressure of atmospheric pressure, sealing pressure or discharge pressure to the suction chamber is formed separately from the suction chamber, and the suction chamber is formed on the partition wall. A movable support member is provided which is reciprocally moved toward the intake valve by a pressure difference between the pressure and the pressure in the predetermined pressure chamber, and a part of the intake valve is floated to the normal operating position and the piston side on the movable support member. A valve pushing member for switching to the inoperative position to be held is provided, and when the piston is moved to the top dead center in the movable supporting member or the valve pushing member, the displacement of the intake valve to the normal position is set. Valve displacement permitting means for permitting Variable displacement compressor that engaged the biasing means for longitudinal movement in response to the valve pressing member to the pressure variation in the suction chamber in the support member. 2. A mounting hole is formed through a housing forming an intake chamber, a bellows is attached to the mounting hole through a lid, and a movable support member is attached to the tip of the bellows, and the movable support member is attached. A valve pressing plate as a valve pressing member is attached to the supporting member, and the pressing piece of the valve pressing plate is itself formed of an elastic material and has a function as a valve displacement allowing means, and the inside of the bellows is The variable capacity compressor according to claim 1, wherein an atmosphere chamber as a predetermined pressure chamber communicating with the atmosphere is provided, and a coil spring as an urging means is provided in the atmosphere chamber. 3. The variable capacity according to claim 1, wherein each of the pushing pieces of the valve pushing plate changes the projecting length so that the timing of pushing the suction valve varies stepwise. Compressor.