JPH06330856A - Capacity controller of displacement variable compressor - Google Patents

Abstract

PURPOSE:To provide a capacity controller of a displacement variable compressor that is able to simply perform a capacity variation conformed to necessity in use of a constant differential pressure regulating valve as well as to cause this capacity variation corresponding to pressure in the compressor with a simple device and a control means. CONSTITUTION:A valve element 29 set up as being opposed from the side of a discharge chamber 21, a diaphragm mechanism 30 to be installed so as to push the valve element 29 to the side of the discharge chamber 21 after being pressed by fixed external pressure so as to make internal pressure Pa become constant, and a solenoid-driven constant differential pressure regulating valve 50 for regulating a pressure differential between the internal pressure Pa in this diaphragm mechanism 30 and pressure Ps in a suction chamber 20 to an optional constant value are all installed in a valve seat 28 formed in the point midway in a passage interconnecting the discharge chamber 21 and a crankcase 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacity control device for a capacity variable compressor used for compressing a refrigerant in a refrigeration cycle of an automobile air conditioner (hereinafter referred to as "car air conditioner").

Since the compressor of a car air conditioner is directly connected to the engine by a belt, the rotation speed cannot be controlled. Therefore, a variable capacity compressor capable of changing the capacity (discharge amount) of the refrigerant is used in order to obtain an appropriate cooling capacity without being restricted by the engine speed.

In such a variable displacement compressor, a compression piston is connected to an oscillating plate mounted on a shaft which is rotationally driven by an engine, and the stroke of the piston is changed by changing the angle of the oscillating plate. Thereby, the capacity of the refrigerant is changed.

[0004]

2. Description of the Related Art In such a variable displacement compressor, in order to change the angle of the oscillating plate as necessary, conventionally, an electromagnetic force is used to control the pressure of the refrigerant sucked into the compressor to a predetermined pressure. An electromagnetic constant pressure valve driven by is provided, and the capacity of the refrigerant is controlled by changing the pressure of the refrigerant drawn into the compressor to change the angle of the oscillating plate.

However, such an electromagnetically driven constant pressure valve is
Since it is necessary to compare it with the atmospheric pressure, which is an almost invariable physical quantity, as a reference, it is necessary to use a bellows, a diaphragm, etc. to make an airtight and smooth structure, and also a very powerful electromagnetic device. Therefore, there is a drawback that the device is large and the cost is high.

Therefore, for example, as disclosed in Japanese Patent Laid-Open No. 5-87047, the pressure difference between the pressure in the crank chamber in which the oscillating plate is arranged and the pressure of the refrigerant sucked into the cylinder for compressing the refrigerant is set to an arbitrary value. There is also one in which an electromagnetically driven constant differential pressure valve that maintains a constant differential pressure is provided, and the capacity of the variable displacement compressor is changed by changing the electromagnetic force of the constant differential pressure valve.

[0007]

However, if the capacity is changed by changing the differential pressure between the pressure in the crank chamber and the pressure of the refrigerant sucked into the cylinder, both pressures are irrespective of the absolute pressure of the compressor. The capacity changes only by the differential pressure of. Therefore, it is necessary to add a device for detecting the absolute pressure and changing the constant differential pressure valve in response to the detected value, and there is a drawback that the device and control become complicated as a whole.

Therefore, according to the present invention, it is possible to easily change the capacity as required by using the constant differential pressure valve, and it is possible to cause the capacity change corresponding to the pressure of the compressor with a simple device and control. An object is to provide a capacity control device for a variable capacity compressor.

[0009]

In order to achieve the above object, a displacement control device for a variable displacement compressor according to the present invention has a variable inclination angle with respect to a rotary shaft 11 in an airtightly formed crank chamber 12. An oscillating body 14 which is provided and is oscillated by the rotational movement of the rotating shaft 11, and the oscillating body 1
4, the refrigerant from the suction chamber 20 is sucked into the cylinder 15 by being reciprocated and compressed, and then discharged into the discharge chamber 2.
And a piston 17 for discharging to the crank chamber 1
In the variable displacement compressor 1 in which the inclination angle of the oscillating body 14 is changed according to the difference between the pressure inside the suction chamber 20 and the pressure inside the suction chamber 20, the discharge amount of the refrigerant is changed. The valve seat 28 formed in the middle of the passage communicating with the crank chamber 12 is disposed so as to face the discharge chamber 21 and the valve body 29 is pressed by a constant external pressure so that the internal pressure Pa becomes constant. A diaphragm mechanism 30 provided to push the valve element 29 toward the discharge chamber 21, an internal pressure Pa of the diaphragm mechanism 30 and a pressure P of the suction chamber 20.
and an electromagnetically driven constant differential pressure valve 50 for adjusting the differential pressure with s to an arbitrary constant value.

The internal pressure P of the diaphragm mechanism 30 is
A second constant difference for maintaining the pressure Pb in the passage 46 between the valve seat 28 and the diaphragm mechanism 30 larger than the pressure Pc in the crank chamber 12 by a certain amount or more in order to secure a above a certain amount. A pressure valve 48 may be provided, or a communication passage 55 that connects the discharge chamber 21 and the inside of the diaphragm mechanism 30 may be provided in order to secure the internal pressure Pa of the diaphragm mechanism 30 above a certain level.

[0011]

The constant differential pressure valve 50 maintains a constant differential pressure between the internal pressure Pa of the diaphragm mechanism 30 and the pressure Ps in the suction chamber 20, and the differential pressure is changed by changing the electromagnetic force of the constant differential pressure valve 50. be able to. Since the internal pressure of the diaphragm mechanism 30 is kept constant, the pressure in the suction chamber 20 changes when the constant differential pressure valve 50 is changed,
Thereby, the pressure Pc in the crank chamber 12 and the suction chamber 20
The differential pressure from the internal pressure Ps changes, the inclination angle of the oscillating body 14 changes, and the compression capacity changes.

The internal pressure Pa of the diaphragm mechanism 30 is the second
The pressure Pb in the passage 46, which is maintained at a pressure higher than the internal pressure Pc in the crank chamber 12 by a constant differential pressure valve 48, is applied to the inside of the diaphragm mechanism 30 or the pressure in the discharge chamber 21 via the communication passage 55. Pd is provided inside the diaphragm mechanism 30 and is kept constant by balancing with the external pressure of the diaphragm mechanism 30.

[0013]

Embodiments will be described with reference to the drawings. Figure 1
It shows the refrigeration cycle used for car air conditioners,
2 is a condenser, 3 is an expansion valve, and 4 is an evaporator. The liquid receiver is not shown.

The low-pressure refrigerant is sent from the evaporator 4 to the compressor 1, and the high-pressure refrigerant compressed by the compressor 1 is sent to the condenser 2. The compressor 1 will be described below.

Reference numeral 11 designates an airtight crank chamber 12
A rocking plate 14 that is arranged inside and is rotatably driven by a drive pulley 13 and that is tilted with respect to the rotating shaft 11 rocks as the rotating shaft 11 rotates.

In a plurality of cylinders 15 arranged in the peripheral portion of the crank chamber 12, a piston 17 is reciprocally movable, and a rod 18 connects the piston 17 and the oscillating plate 14. .

Therefore, when the rocking plate 14 rocks, the piston 17 reciprocates in the cylinder 15 and the cylinder 1
The refrigerant is drawn from the suction chamber 20 formed in the back of the cylinder 5 into the cylinder 15
The refrigerant is sucked in, the refrigerant is compressed, and then discharged into the discharge chamber 21.

The suction chambers 20 and the discharge chambers 2 are connected to each other.
The ones communicate with each other through communication passages 23 and 24, respectively, and the suction chamber 20 and the crank chamber 12 communicate with each other through a thin fixed orifice 25 serving as a relief passage.

The inclination angle of the oscillating plate 14 is determined by the pressure difference "Pc-" between the pressure Pc in the crank chamber 12 and the pressure Ps in the suction chamber 20.
Ps ”, the stroke of the piston 17 changes when the tilt angle of the oscillating plate 14 changes, so the discharge amount (capacity) of the compressor 1 changes.

A valve seat 28 is provided in the middle of a high pressure communication passage 27 which communicates between the discharge chamber 21 and the crank chamber 12, and a ball valve 29 is provided from the high pressure side, that is, the discharge chamber 21 side, to the valve seat 2.
8 are arranged to face each other.

The ball valve 29 has an atmospheric pressure and a disc spring 31.
The diaphragm mechanism 30, which is pressed by a constant external pressure by the
It is arranged to be pushed to the side.

FIG. 2 shows an enlarged view of the ball valve 29 and the diaphragm mechanism 30. The disc spring 31 can adjust the spring pressure by tightening the adjusting screw 33 and faces the diaphragm 35. The pressing force is applied to the spring receiving plate 34.

The diaphragm receiving plate 36 facing the back surface (inner surface) of the diaphragm 35 is movable in the diaphragm chamber 37 in the direction perpendicular to the surface of the diaphragm 35, and the diaphragm receiving plate 36 and the ball valve 29. The rod 32 is arranged between the two so as to be movable back and forth in the axial direction.

A plurality of O-rings 39 for sealing are attached between the outer wall surface of the diaphragm chamber 37 and the receiving surface around the outer wall surface of the diaphragm chamber 37 to maintain the airtightness between the inner and outer surfaces of the diaphragm 35. 40 is a filter.

The rod 32 is fitted in the hole formed by the wall member of the diaphragm chamber 37, and the opening 42 reaching the crank chamber 12 is formed between the fitting portion 43 and the ball valve 29, and the suction is performed. An opening 44 reaching the chamber 20 is formed on the diaphragm chamber 37 side between the fitting portion 43 and the diaphragm 35.

No O-ring is attached to the fitting portion 43 of the rod 38 so that the refrigerant can leak through the gap. Here, the pressure in the discharge chamber 21 is Pd, the pressure in the space 46 between the ball valve 29 and the fitting portion 43 is Pb, and the pressure in the diaphragm chamber 37 between the fitting portion 43 and the diaphragm 35 is It is Pa.

Returning to FIG. 1, the space 46 and the crank chamber 12
A constant differential pressure valve 48 for maintaining the pressure Pb in the space 46 higher than the pressure Pc in the crank chamber 12 by a constant pressure is provided in the high pressure communication passage 27 between In addition,
In this embodiment, as the constant differential pressure valve 48, a valve that biases a ball valve with a coil spring is used, but a valve that uses electromagnetic force may be used.

With this structure, the pressure Pb in the space 46, which is maintained higher than the pressure Pc in the crank chamber, leaks into the diaphragm chamber 37 through the fitting portion 43, and the pressure Pa in the diaphragm chamber 37 is constant. To be kept at.

A constant differential pressure valve 50 for urging the ball valve 52 toward the diaphragm chamber 37 side by an electromagnetic solenoid 51 is provided in the middle of a low pressure communication passage 49 connecting the diaphragm chamber 37 and the suction chamber 20. .

Therefore, this electromagnetically driven constant differential pressure valve 50 is
By the pressure Pa in the diaphragm chamber 37 and the suction chamber 2
The pressure difference ΔP = Pa−Ps from the pressure Ps within 0 is always kept constant.

When the current value applied to the electromagnetic solenoid 51 is changed, the pressure difference ΔP changes, but since the pressure Pa in the diaphragm chamber 37 is maintained constant, only the pressure Ps in the suction chamber 20 is changed. Act to change.

In the displacement control device for a variable displacement compressor having such a structure, when the load on the evaporator 4 decreases, the pressure Ps in the suction chamber 20 decreases and the pressure Pa in the diaphragm chamber 37 decreases. As a result, the ball valve 29 is pushed open by the diaphragm mechanism 30, and the refrigerant is supplied from the discharge chamber 21 to the crank chamber 12.

Then, the pressure Pc in the crank chamber 12 increases, "Pc-Ps" increases, and the tilt angle of the oscillating plate 14 decreases. Then, the stroke of the piston 17 is reduced and the discharge amount (volume) is reduced. When the load on the evaporator 4 becomes large, the capacity becomes large due to the reverse operation. In this way, the capacity automatically changes according to the load of the evaporator 4.

The electromagnetic solenoid 5 of the constant differential pressure valve 50
If the current value given to 1 is changed, the pressure Ps in the suction chamber 20 is changed.
As a result, "Pc-Ps" also changes, the tilt angle of the oscillating plate 14 changes, the stroke of the piston 17 changes, and the capacity changes.

Therefore, regardless of the load on the evaporator 4, the capacity of the compressor 1 can be changed by changing the current value applied to the electromagnetic solenoid 51 as necessary. Moreover, since Pc of "Pc-Ps" is constant and only Ps is changed, the capacity change corresponding to the pressure value of Ps is performed.

The present invention is not limited to the above embodiment, and for example, as shown in FIG. 3, in order to secure the pressure Pa in the diaphragm chamber 37, the fixed orifice 55 is provided from the discharge chamber 21 to the diaphragm. The pressure Pd in the discharge chamber 21 may be leaked to the diaphragm chamber 37 by communicating with the chamber 37. In this way, the constant differential pressure valve in the middle of the high pressure communication passage 27 is unnecessary.

[0037]

According to the capacity control device for a variable capacity compressor of the present invention, any desired capacity change can be easily performed by using a constant differential pressure valve, and the capacity change is caused by the compressor. Since it occurs according to the pressure, it has an excellent effect that it can be performed by a simple device and control that do not require a device for pressure monitoring or control.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a displacement control device for a variable displacement compressor according to a first embodiment.

FIG. 2 is an enlarged sectional view of the diaphragm mechanism of the first embodiment.

FIG. 3 is a vertical sectional view of a capacity control device for a capacity variable compressor according to a second embodiment.

[Explanation of symbols]

 1 Compressor 12 Crank chamber 14 Swing plate 15 Cylinder 17 Piston 20 Suction chamber 21 Discharge chamber 28 Valve seat 29 Valve body 30 Diaphragm mechanism 50 Constant differential pressure valve 51 Electromagnetic solenoid

[Procedure amendment]

[Submission date] June 2, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG. 1 is a vertical sectional view of a variable capacity compressor according to a first embodiment.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

FIG. 3 is a vertical sectional view of a variable capacity compressor according to a second embodiment.

Claims (3)

[Claims] 1. A crank chamber (12) formed in an airtight manner is provided with a variable inclination angle with respect to a rotary shaft (11) and is driven by the rotary motion of the rotary shaft (11) to perform a swing motion. The oscillating body (14) is connected to the oscillating body (14) and reciprocates so that the refrigerant from the suction chamber (20) is sucked into the cylinder (15) and compressed, and then discharged to the discharge chamber (21). A discharge piston (17), and the pressure in the crank chamber (12) and the suction chamber (20).
In the variable displacement compressor (1) in which the inclination angle of the oscillating body (14) is changed by the difference between the internal pressure and the discharge amount of the refrigerant, the discharge chamber (21) and the crank chamber ( (12) A valve seat (28) formed in the middle of a passage communicating with the valve body (29) facing the discharge chamber (21) side and a constant internal pressure (Pa). A diaphragm mechanism (30) provided to push the valve element (29) toward the discharge chamber (21) by being pressed by a constant external pressure, an internal pressure (Pa) of the diaphragm mechanism (30) and the suction chamber ( 20) A capacity control device comprising an electromagnetically driven constant differential pressure valve (50) for adjusting the differential pressure to the pressure (Ps) in 20) to an arbitrary constant value. 2. The internal pressure (P) of the diaphragm mechanism (30)
In order to secure a) above a certain level, the pressure (Pb) in the passage (46) between the valve seat (28) and the diaphragm mechanism (30) is adjusted to the pressure (Pb) in the crank chamber (12).
2. The displacement control device for a variable displacement compressor according to claim 1, further comprising a second constant pressure differential valve (48) for maintaining a value larger than that of c) by a certain amount or more. 3. The internal pressure (P) of the diaphragm mechanism (30)
The capacity of the variable capacity compressor according to claim 1, further comprising a communication passage (55) which connects the discharge chamber (21) and the inside of the diaphragm mechanism (30) in order to secure a) above a certain level. Control device.