JPH0716071Y2 - Variable capacity compressor - Google Patents

Description

[Detailed Description of the Invention] << Industrial Application Field >> The present invention relates to a variable capacity compressor used in an air conditioner for a vehicle or the like.

<< Prior Art >> A variable displacement compressor capable of increasing and decreasing the intake amount is easy to prevent overcooling when used in a vehicle air conditioner, for example, and has relatively few drive system switching, resulting in a driving feeling. It is also superior to the rotary compressor with a constant capacity in terms. An example of this type of compressor is disclosed in JP-A-62-265491.

As shown in FIG. 3, the variable displacement compressor disclosed in this publication includes a rotary shaft 1, a front head 2, a case 3, a cam ring 4, a front side block 5, a rear side block (not shown), and the like. In particular, the adjust plate 6 is rotatably housed in the concave portion of the front side block 5, and the adjust plate 6 is provided with a pressure receiving portion (not shown) on one side thereof. This pressure receiving portion is slidably fitted in the arc-shaped pressure working chamber 7,
A seal member (not shown) having a special shape is attached to the sliding portion of the pressure receiving portion, which is the outer periphery of the pressure receiving portion. Further, the suction pressure on the suction chamber 9 side is applied to one of the pressure working chambers 7 divided into two by the pressure receiving portion, and the pilot pressure is applied to the other, and the pilot pressure is divided into the discharge chamber 14 and the pressure working chamber 7. It is supplied from an orifice (not shown) communicating with the other and the opening / closing valve mechanism 8 side. Here, the on-off valve mechanism 8 selectively pilots the suction pressure or the discharge pressure in accordance with the relative variation between the valve opening force of the suction chamber 9 against the ball valve 16 by the bellows 10 and the valve closing force of the spring 11 and the plunger 12. The pressure is introduced to the other of the pressure working chambers 7. Discharge pressure is applied to the rear end of the plunger 12.

A bypass opening (not shown) is formed on the outer circumference of the adjust plate 6, and the area of the suction port is increased or decreased by rotating the bypass opening around the rotation center axis so that the suction opening can be retracted into the rotor 15 and slid on the inner circumference of the cam ring 4. The discharge amount can be adjusted by adjusting the compression start timing of each vane mounted so as to be in contact with each other.

Further, since the plunger 12 presses the ball valve 16 in the direction of closing the suction chamber 9 by the discharge pressure, the opening / closing operation of the ball valve 16 is stabilized and the opening / closing valve mechanism 8 is prevented from hysteresis. That is, without the plunger 12, the sum of the biasing force of the spring 11 and the pressure Pc in the pressure working chamber 7 acts in the direction of opening the ball valve 16, but this pressure Pc is Since the value is always fluctuating, when the bellows 10 expands and contracts according to the change of the suction pressure Ps and the ball valve 16 opens and closes, it is difficult to open and close the ball valve 16 in a constant state at all times. Is likely to occur.

Therefore, when the plunger 12 is provided, the plunger 12 always presses the ball valve 16 in the valve opening direction by the discharge pressure Pd, so that the ball valve 16 is not affected by the fluctuation of the pressure Pc. Because the discharge pressure Pd is always almost constant, and Pd
Because of the relationship of ≧ Pc, the ball valve 16 is always affected by the higher pressure, that is, Pd, and is not affected by the fluctuation of the value of Pc. Therefore, the force that the ball valve 16 receives in the valve opening direction is always a constant force, which is the sum of the biasing force of the spring 11 and the discharge pressure Pd, so that the open / close operation state is always constant and hysteresis is prevented. The controllability is improved.

Further, the pressure receiving area where the plunger 12 receives the discharge pressure Pd and the pressure receiving area (valve seat area) where the ball valve 16 receives the pilot pressure Pc are formed to be substantially the same, and a certain set pilot pressure Pc is used as a boundary for the ball valve. 16 opens and closes with good pressure response.

<Problems to be Solved by the Invention> By the way, in the variable displacement compressor having the above structure, the other end of the pressure working chamber 7 and the discharge chamber 14 are communicated with each other by an orifice and a communication passage 13 not shown, and the discharge inside the discharge chamber 14 is made. The pressure is directly guided as pilot pressure.

Therefore, when the compressor is operating at the maximum capacity, a pressure substantially equal to the discharge pressure acts on the pressure receiving portion of the pressure working chamber 7, and the sealing member of this pressure receiving portion is easily deformed,
There is a problem that the sealing property and the life are reduced.

Further, when the compressor shifts from the maximum capacity operation to the capacity control operation, the bellows 10 of the opening / closing valve mechanism 8 expands in response to the pressure decrease in the suction chamber 9, the ball valve 16 is opened, and the communication passage 13 is opened.
The inside is the control pressure (the range from the suction pressure to a pressure higher than this suction pressure by about 1.5 kg / cm ² ). Then, the other side of the pressure working chamber 7 also becomes a control pressure, the pressure receiving portion moves, and the adjusting plate 6 is rotated to perform the capacity control operation.
The discharge pressure is directly introduced as a pilot pressure to the other of the pressure working chambers 7 from an orifice (not shown).
It takes time to reduce the internal pressure to the control pressure, resulting in poor responsiveness.

The present invention has been made in view of the above problems, and provides a variable displacement compressor that solves the problems caused by the control portion of the adjust plate directly receiving the discharge pressure and improves the responsiveness to pressure fluctuations. The purpose is to

<Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention is provided in the middle of a passage communicating between a suction chamber and a discharge chamber of a compressor, and this passage is provided in response to fluctuations in the suction chamber pressure. An opening / closing valve mechanism for controlling the opening / closing of the valve, and an actuator cylinder that operates according to the operation of the opening / closing valve mechanism. The actuator cylinder is communicated with the opening / closing valve mechanism via a pilot pressure passage, and the pilot pressure passage is provided. In addition, when the pilot pressure exceeds a set value, a pressure regulating valve that opens this passage to the suction chamber side is interposed.

<Operation> In the variable displacement compressor having the above structure, when the compressor is in the maximum displacement operation state, the pressure difference between the discharge chamber and the suction chamber becomes large, and the pilot pressure also becomes high. When the pilot pressure exceeds a certain level, the pressure control valve opens, opening the pilot pressure passage to the suction chamber. As a result, the pilot pressure drops smoothly, the transition from maximum capacity operation to capacity control operation is performed with good responsiveness, and the rise in pressure in the actuator cylinder is suppressed to a low level, preventing deformation of the seal. The sealing property is improved.

<< Embodiment >> An embodiment of the present invention will be described below with reference to the accompanying drawings.

The overall configuration of the variable capacity compressor of the present invention will be described below.
It is as shown in the figure.

Reference numeral 21 in the figure denotes a tubular cam ring, and a front side plate 22 is attached to the front surface (left side surface in the figure) of the cam ring 21. A rear side plate 23 is attached to the rear surface (right side surface in the figure) of the cam ring 21. Further, a head cover 26 that covers the front side plate 22 and forms an intake chamber 25 therein is attached to the front surface of the cam ring 21. Cam ring
A rear cover 28, which covers the rear side plate 23 and forms a discharge chamber 27 therein, is attached to the rear surface of the 21.

A rotor 30 is mounted inside the cam ring 21, and one end of the rotor 30 is rotatably supported by the rear side plate 23 and the other end thereof is rotatably supported by a rotary shaft 31 rotatably supported by the head cover 26. ing. A plurality of vanes (not shown) are arranged in the rotor 30, and a working chamber 32 is formed between the vane, the cam ring 21, and the rotor 30. Then, the front side plate 22 is provided with the fluid in the suction chamber 25 as a working chamber.
A suction port (not shown) for sucking into the 32 is provided, and a discharge port (not shown) for discharging the fluid pressurized in the working chamber 32 to the discharge chamber 27 is formed in the rear side plate 23. Further, the front side plate A bypass passage 33 (22 in FIG. 1) is opened in the valve 22 when the pressure difference between the discharge chamber 27 and the inside of the suction chamber 25 becomes large so that the fluid in the working chamber 32 is circulated to the suction chamber 25 side. (See) is formed.

A circular recess 22a is formed on the cam ring 21 side of the front side plate 22, and an adjust plate 34 is rotatably mounted in the circular recess 22a. Circular recess 22
Inside a, a thrust bearing 35 that rotatably presses the adjust plate 34 and presses it against the rotor 30 is attached. A pair of cutouts 34a, 34b (see FIG. 1) are provided on the outer periphery of the adjust plate 34 at positions symmetric with respect to the center points thereof. By rotating the adjust plate 34, the cutouts 34a, 34b are formed. Adjust the opening of the bypass passage 33,
The amount of fluid that returns from the working chamber 32 to the suction chamber 25 is controlled.

An opening / closing valve mechanism 37 and an actuator cylinder 38 are provided in the head cover 26. The on-off valve mechanism 37 is the first
As shown in the figure, a bellows 40 having a coil spring built therein, a bellows chamber 42 in which the bellows 40 is mounted and which is communicated with a suction chamber 25 by a communication passage 41,
A set spring 43 that is built in the bellows chamber 42 and presses the tip of the bellows 40, a communication passage 44 that communicates the bellows chamber 42 with the discharge chamber 27, and a communication passage 44 that is interposed in the communication passage 44.
And a ball valve 45 for opening and closing. Ball valve
45 is a ball valve body 45a inserted into the ball valve chamber 45b,
A valve seat 46 formed on the bellows chamber 42 side in the communication passage 44, a needle 47 for pressing the ball valve body 45a from the bellows chamber 42 side via the valve seat 46, and a ball valve body 45a for pressing the valve seat 46 on the valve seat 46. The coil spring 48 and the plunger 49 for preventing hysteresis, the needle 47 is pushed by the expansion of the bellows 40 due to the decrease in the pressure in the bellows chamber 42 and the ball valve body 45a is pushed open, and the discharge chamber 27 and Inhalation chamber 25 and
The communication path 44 and the communication path 41 communicate with each other. In the gap between the plunger 49 and the communication passage 44, the first throttle 44
The second diaphragm 44b is formed in the gap between the needle 47 and the communication passage 44.

The actuator cylinder 38 is mainly mounted in the cylinder portion 50, a cylinder portion 50 mounted in the head cover 26, a guide rod 51 extending inward from a base end 50a of the cylinder portion 50, and mounted therein. A cylindrical piston 52, the movement of which is supported by a guide rod 51, and a piston 52 that is inserted into the piston 52 and is also inserted into the guide rod 51 so that a reaction force is applied to the base end 50a side of the cylinder portion 50. It is composed of a return spring 53 that presses the tip 50b side of the cylinder portion 50. Tip 50b in cylinder 50
A pilot pressure chamber 54 is defined by the piston 52 on the side, and the pilot pressure chamber 54 is communicated with the ball valve chamber 45b in the communication passage 44 through the pilot pressure passage 55.

Further, a vertically long slit 61 is provided on the base end 50a side of the cylinder portion 50. A longitudinally elongated groove 62 is formed along the slit 61 on the outer side of the cylinder portion 50, and a link member 63 is attached to the groove 62. This link member
One end of 63 is connected to the base end of the piston 52 by a connecting pin 64, and the other end is connected to an adjust plate 34 mounted in the front side plate 22 by a connecting pin 65. The adjustment plate 34 is rotated by the movement of 52, and the bypass passage 33
The opening degree of is controlled. Reference numeral 66 denotes a seal member attached to the tip of the piston 52 to seal between the piston 52 and the cylinder portion 50.

A pressure adjusting valve 70 is provided in the pilot pressure passage 55 that connects the pilot pressure chamber 54 and the ball valve chamber 45b. The pressure adjusting valve 70 includes a ball valve body 72 that opens and closes a passage 71 that communicates between the pilot pressure passage 55 and the suction chamber 25,
A valve seat 73 formed on the pilot pressure passage 55 side of the ball valve body 72, a coil spring 74 for urging the ball valve body 72 toward the valve seat 73 side, and a snap for supporting the base end portion of the coil spring 74. It consists of a ring 75. The set pressure at which the pressure adjusting valve 70 operates is adjusted by changing the spring constant of the coil spring 74. This set pressure, that is, the pilot pressure passage where the pressure regulating valve 70 starts to operate
The pressure difference between the suction chamber 25 and the suction chamber 25 is 3 to 5 kg / cm in this embodiment.
It is set to about ² . Further, the set pressure required to move the piston 52 of the actuator cylinder 38 to the base end 50a against the reaction force of the return spring 53 is 1.5 kg / in the difference in pressure between the pilot pressure passage 55 and the suction chamber 25. It is set to about cm ² .

Reference numeral 73 in FIG. 2 indicates a pulley connected to a power source such as an engine by a belt, and reference numeral 74 indicates an electromagnetic clutch for connecting and disconnecting the rotating shaft 31 and the pulley 73.

In the variable displacement compressor configured as described above, in the operation stopped state, there is no difference in pressure between the suction chamber 25 and the discharge chamber 27, and the piston 52 of the actuator cylinder 38 is urged by the return spring 53 so that the cylinder portion 50. Has moved to the tip 50b side. As a result, the adjusting plate 34 connected to the piston 52 via the link member 63 and the connecting pin 65 is rotated to adjust the opening degree of the bypass passage 33 to the maximum.

When the compressor is operated, the pulley 73 is driven by the driving force from the power source.
Are driven to rotate the rotor 30. This allows the inhalation chamber
The fluid in 25 is sucked into the working chamber 32 and is pressurized to the discharge chamber.
It is discharged to 27. Then, the fluid in the discharge chamber 27 is supplied to an external actuator or the like. At this time, since the suction pressure in the suction chamber 25 is also high, the pressure in the bellows chamber 42 is also high, and in the opening / closing valve mechanism 37, the bellows 40 is compressed and the ball valve 45 is pressed by the spring 48. It is blocked. Therefore, in the pilot pressure chamber 54 of the actuator cylinder 38, the discharge pressure in the discharge chamber 27 is the first throttle.
It is supplied via 44a, the ball valve chamber 45a, and the pilot pressure passage 55, and the piston 52 is pressed toward the base end 50a. As a result, the adjusting plate 34 connected by the link member 63 and the connecting pin 65 is rotated to reduce the opening degree of the bypass passage 33 to the minimum, and the maximum capacity operation is started.

When the capacity increases, the suction pressure of the suction chamber 25 decreases, the internal pressure of the bellows chamber 42 of the on-off valve mechanism 37 communicating with this decreases, and the bellows 40 expands. The needle 47 is pushed by the extension of the bellows 40, and the ball valve body 46 is pushed open. As a result, the discharge pressure in the discharge chamber 27 leaks into the bellows chamber 42, the pilot pressure supplied to the actuator cylinder 38 through the pilot pressure passage 55 decreases, and the piston 52
Is urged by the return sprig 53 to move to the tip end 50b side, the adjust plate 34 connected by the link member 63 and the pin 65 rotates to open the bypass passage 33, and the capacity control operation starts.

As described above, during the operation of the compressor, the piston 52 moves according to the change of the pilot pressure supplied to the pilot pressure chamber 54 of the actuator cylinder 38, and the displacement is controlled. Further, since the discharge pressure is constantly applied to the ball valve body 45a via the plunger 49, hysteresis is prevented and the pilot pressure is obtained through the first throttle portion 44a, so that the discharge pressure is relatively high. The ball valve element 45a operates with a slightly lower suction pressure and with a slightly higher suction pressure when the discharge pressure is relatively low, thereby improving the responsiveness of the opening / closing valve mechanism.

However, when the temperature is high in summer and the compressor is operated at a medium or low speed, the compressor is operated at the maximum capacity, but the suction pressure becomes high and the bellows 40 contracts to open and close the valve mechanism.
37 is closed. On the other hand, the discharge pressure is also high, and the pilot pressure guided to the pilot pressure chamber 54 via the passage 55 is also high. When the pilot pressure exceeds the above-mentioned set pressure, the pressure adjusting valve 70 is opened and the pilot pressure is released to the suction chamber 25, so that the pilot pressure is reduced and the capacity control operation is immediately started, and the pilot pressure chamber 54 The seal member 66 is protected by suppressing an excessive increase in pressure therein.

<Effect of Device> As described above, according to the variable displacement compressor of the present invention, the actuator cylinder is communicated with the on-off valve mechanism through the pilot pressure passage, and the pilot pressure is supplied to the pilot pressure passage. Since a pressure control valve that opens this passage to the suction chamber side is installed when the set value is exceeded, an excessive rise in pilot pressure can be prevented if the discharge pressure does not decrease even if the maximum operation is performed but the suction pressure does not fall. It is possible to suppress the deformation of the seal member in the actuator cylinder, thereby extending the life of the seal member and improving the sealability.

Also, when the pilot pressure exceeds the set pressure, the pilot pressure is released to the suction chamber side, so the pilot pressure drops smoothly and the transition from maximum capacity operation to capacity control operation is performed quickly, and the response of capacity control When the compressor is used in a vehicle air conditioner, efficient cooling can be performed.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a variable capacity compressor of the present invention, FIG. 2 is a vertical sectional view showing a variable capacity compressor of the present invention, and FIG. 3 is a sectional view showing a main part of a conventional variable capacity compressor. It is a figure. 25 ... suction chamber, 27 ... discharge chamber, 32 ... working chamber, 33 ... bypass passage, 34 ... adjust plate, 37 ... open / close valve mechanism, 38 ... actuator cylinder, 55 ... pilot pressure passage, 70 ... Pressure control valve.

Claims (1)

[Scope of utility model registration request] 1. An on-off valve mechanism for controlling the opening and closing of a passage, which is interposed in the middle of a passage communicating between a suction chamber and a discharge chamber of a compressor in accordance with a change in pressure in the suction chamber, and an operation of the on-off valve mechanism. An actuator cylinder that operates in response to the opening and closing valve mechanism. The actuator cylinder communicates with the on-off valve mechanism through a pilot pressure passage, and when the pilot pressure exceeds a preset value, the passage is formed in the suction chamber. A variable capacity compressor having a pressure regulating valve opened to the side.