JP2000283029A - Capacity control valve and variable displacement compressor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacity control valve constituted so that an suction chamber pressure control point is decided readily with respect to the current carrying amount of an electromagnet device and a variable displacement compressor can be maintained to the minimum capacity forcedly in a non-current carrying state. SOLUTION: A movable valve element 18 for opening/closing communication passages 17a, 17b for communicating the delivery chamber with a crank room of a variable displacement compressor is provided. Pressure sensitive members 12, 15 for sensing the pressure of the suction chamber and telescoping to drive the valve element are installed on oneside of the valve element. On the other side of the valve element, an electromagnet device 20 for giving the external force to the pressure sensitive member by the electromagnetic force is installed. A through hole 21 is provided on the valve element and one part of the electromagnet device is inserted in the through hole and engaged with the pressure sensitive member.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement compressor used in, for example, an air conditioner for a vehicle, and more particularly to a displacement control valve for the compressor.

[0002]

2. Description of the Related Art As a conventional displacement control valve for a variable displacement compressor, there is a displacement control valve for controlling a stroke of a piston by adjusting a pressure in a crank chamber as shown in FIG. The displacement control valve senses the pressure in the suction chamber with the bellows 1 and opens and closes the ball valve 2 in accordance with the pressure to adjust the amount of gas from the discharge chamber introduced into the crank chamber. This is a so-called internal control type bellows valve structure. Based on this bellows valve structure, an electromagnetic device 3 is arranged above the ball valve 2 so that an electromagnetic force acts on the ball valve 2. Therefore, FIG.
As shown in (1), the operating point of the bellows valve, that is, the pressure control point of the suction chamber, can be changed by the amount of electricity supplied to the electromagnetic device.

[0003]

The capacity control valve shown in FIG. 7 has a structure in which the ball valve receives the discharge chamber pressure.
As shown in FIG. 8, even if the amount of current supplied to the electromagnetic device is constant, the suction chamber pressure control point changes due to the discharge chamber pressures Pd1, Pd2, Pd3,. That is, there is a problem that the suction chamber pressure control point is not uniquely determined with respect to the amount of current supplied to the electromagnetic device, and a control method for performing optimal discharge displacement control becomes complicated.

In the structure shown in FIG. 7, there is an upper limit to the pressure in the suction chamber of the variable displacement compressor.
It cannot be controlled at cm ² G or more.

[0005] During normal vehicle running, the pressure in the suction chamber is 2k.
There is no problem because the control is often maintained at around g / cm ² G. On the other hand, when the vehicle is accelerating, the discharge capacity may be reduced in order to enhance the acceleration performance. In that case, the discharge capacity decreases and the pressure in the suction chamber increases. When the pressure in the suction chamber rises to 3.7 kg / cm ² G, the discharge capacity is controlled to maintain this pressure, and in some cases, the minimum capacity cannot be maintained depending on the operating conditions, which is important for the running performance of the vehicle. May have an effect.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to make it possible to uniquely determine the suction chamber pressure control point with respect to the amount of current supplied to the electromagnetic device, and to forcibly maintain the variable capacity compressor at the minimum capacity when no power is supplied. An object of the present invention is to provide a displacement control valve configured as described above.

Another object of the present invention is to provide a variable displacement compressor provided with the displacement control valve.

[0008]

According to the present invention, there is provided a valve element movable in a predetermined direction for opening and closing a communication passage for communicating a discharge chamber and a crank chamber of a variable displacement compressor, and A pressure-sensitive member that is disposed on one side of the valve body and senses the surrounding reference pressure and expands and contracts in the predetermined direction to drive the valve body,
A displacement control valve for a variable displacement compressor, which is disposed on the other side of the valve body in the predetermined direction and includes an external force applying mechanism for applying the external force in the predetermined direction to the pressure-sensitive member. A displacement control valve for a variable displacement compressor is obtained, wherein the displacement control valve has a through hole penetrating in the predetermined direction, and the external force applying mechanism is inserted into the through hole and engaged with the pressure-sensitive member.

The external force applying mechanism includes a solenoid coil controlled to be energized and de-energized, and a solenoid rod driven by the electromagnetic force of the solenoid coil. The solenoid rod may be configured to be engaged so that when the solenoid coil is energized, the solenoid rod compresses the pressure-sensitive member in the predetermined direction.

Further, a balance chamber communicating with the through hole and acting on the valve body in the predetermined direction may be provided.

[0011] Further, a first spring member for urging the valve body with a first urging force in a closing direction with a first urging force, wherein the pressure-sensitive member drives the valve body in an opening direction when extended. Good.

Further, a valve casing accommodating the pressure-sensitive member movably in the predetermined direction and a second urging force larger than the first urging force move the pressure-sensitive member in the opening direction of the valve body. And a second spring member biased toward.

According to the present invention, there is provided a variable displacement compressor having a discharge chamber, a crank chamber, and a communication passage communicating therewith, comprising the above-described displacement control valve, wherein the displacement control valve is provided by the displacement control valve. A variable displacement compressor characterized in that opening and closing are controlled is obtained.

[0014]

FIG. 1 shows a displacement control valve for a variable displacement compressor according to an embodiment of the present invention.

The displacement control valve 10 controls the compression displacement of the variable displacement compressor.
And a bellows 12 which is disposed in the valve casing 11 and which can expand and contract in a predetermined direction, that is, a vertical direction in which the inside is evacuated and a spring is disposed, and a lower end of the bellows 12 in the drawing,
A guide 13 movably supported by the valve casing 11, a spring member 14 for urging the guide 13 upward in the drawing, and one end connected to the upper end of the bellows 12 in the drawing so as to be movable to the valve casing 11. The pressure-sensitive rod 15 supported as described above is disposed in the valve chamber 16 and abuts on the other end, that is, the upper end, of the pressure-sensitive rod 15, and is connected to the discharge chamber of the variable displacement compressor according to the expansion and contraction of the bellows 12. A valve element 18 that opens and closes between the communication passage 17a and the communication passage 17b connected to the crank chamber
A spring member 19 for urging the valve element 18 downward, and the valve element 1
8 and an electromagnetic device 20 disposed above. The urging force of the spring member 19 is smaller than the urging force of the spring member 14.

The valve body 18 has a through hole 21 extending vertically. A balance chamber 22 is formed in the valve casing 11 so as to face a surface 18b opposite to the contact surface 18a that contacts the valve seat of the valve element 18. The balance chamber 22 is configured to receive the pressure of the crank chamber through the through hole 21. The crank chamber pressure receiving area on the contact surface 18a side of the valve element 18 and the crank chamber pressure receiving area on the opposite surface 18b are set to be equal. The side surface 18c of the valve element 18 is supported by the valve casing 11 so as to be movable.

The electromagnetic device 20 includes a fixed stator 23,
A solenoid coil 24 arranged around the stator 23 and controlled to be energized and de-energized; a plunger 26 arranged in a plunger chamber 25 above the stator 23; and a solenoid coil arranged at the center of the stator 23 so as to be vertically movable. 24
And a solenoid rod 27 driven via a plunger 26 by the electromagnetic force. The solenoid rod 27 is in direct contact with the pressure-sensitive rod 15. The electromagnetic device 20 generates an electromagnetic force when the solenoid coil 24 is energized, and urges the pressure-sensitive rod 15 downward through the solenoid rod 27.

Next, a variable displacement compressor provided with the displacement control valve 10 described above will be described with reference to FIG.

This variable displacement compressor is used in an air conditioner for a vehicle, and includes a tubular casing 31, a front housing 32 having one end closed in the axial direction of the casing 31, an axial direction of the casing 31 and the like. Cylinder head 3 mounted at the end via valve plate assembly 33
4 is included. Casing 31, front housing 3
2, and the cylinder head 34 are fixed to each other by bolts 35.

The casing 31 integrally has a cylinder block 36 therein. At the center of the casing 31, a shaft 37 extends in the axial direction. This shaft 37
Is rotatably supported by the front housing 32 and the cylinder block 36.

A pulley 38 is rotatably supported by the front housing 32. The pulley 38 is driven by a vehicle engine. A ring-shaped armature 41 is supported at the outer end of the shaft 37 via a rubber member 39 so as to be movable in the axial direction.

The armature 41 is opposed to the shaft end face of the pulley 38, and is controlled by a suction device 42 so as to be sucked by the pulley 38 or separated therefrom. That is, when the suction device 42 is driven, the armature 41 is suctioned to the pulley 38 by the electromagnetic force, and the torque of the engine is transmitted to the shaft 37. On the other hand, when the driving of the suction device 42 is stopped, the armature 41 is separated from the pulley 38 by the restoring force of the rubber member 39, and the torque of the engine is not transmitted to the shaft 37.

A crank chamber 43 is defined between the front housing 32 and the cylinder block 36. A rotor 44 is disposed in the crank chamber 43, and the rotor 44 is fixed to the shaft 37. A swash plate 46 is connected to the rotor 44 via a hinge mechanism 45.
The hinge mechanism 45 includes a swash plate 46 with respect to the axis of the shaft 37.
Is made variable. The swash plate 46 is the rotor 4
Rotate with 4.

A plurality of pistons 4 are provided around the swash plate 46.
7 are engaged via the shoes. The piston 47 is slidably inserted in a corresponding cylinder bore 48 formed in the cylinder block 36 in the axial direction. When the swash plate 46 rotates, the piston 47 has a corresponding cylinder bore 48 with a stroke determined by the inclination angle of the swash plate.
Reciprocating within.

The cylinder head 34 has a suction chamber 51 formed in a peripheral portion thereof and a discharge chamber 52 formed in a central portion thereof. A known refrigeration circuit is connected between the suction chamber 51 and the discharge chamber 52.

The valve plate assembly 33 includes a cylinder bore 48.
A suction port 53 and a discharge port 54 for communicating the suction port with a suction chamber 51 and a discharge chamber 52, and a valve mechanism for the suction port 53 and the discharge port 54 are provided.

When the shaft 37 rotates, the piston 47
Causes a reciprocating motion in the cylinder bore 48. Piston 4
In accordance with the reciprocation of 7, the refrigerant gas of the refrigeration circuit is sucked from the suction chamber 51 into the cylinder bore 48 and discharged from the discharge chamber 52 into the refrigeration circuit. The compression capacity of the variable displacement compressor is determined by the piston 47 determined by the inclination angle of the swash plate 46.
Depends on the stroke. In order to control the inclination angle of the swash plate 46, the above-described displacement control valve 10 is provided in a control valve chamber 55 formed in the cylinder head 34. At this time, the communication passage 17a is connected to the discharge chamber 52 via the passage 56, and the communication passage 17b is connected to the crank chamber 43 via the passage 57. The space around the bellows 12 is connected to the suction chamber 51.

The operation of the displacement control valve 10 will be described with reference to FIGS. 3 to 6 in addition to FIGS.

Since no electromagnetic force is generated when the solenoid coil 24 is not energized, there is no force for urging the valve element 18 in the valve closing direction in a pressure balanced state, and the pressure in the suction chamber 51 of the variable displacement compressor is high. In this case, the bellows 12 contracts, but is urged upward in the figure by the spring member 14, so that the valve element 18 is always open as shown in FIG.

When the compressor is started in this state, the gas in the discharge chamber 52 is always introduced into the crank chamber 43 and the pressure difference between the crank chamber 43 and the suction chamber 51 increases, so that the capacity is maintained at the minimum.

The biasing force of the spring member 14 is small, for example, a current value i0 (A) applied to the solenoid coil 24.
Is set smaller than the electromagnetic force generated by. For this reason, the valve element 18 can be closed in the current range of i0 (A) or more.

For example, the compressor is started from a state where the pressure is balanced at 6 kg / cm ² G, and the suction chamber pressure is 2 kg / cm ² G.
When the amount of current supplied to the solenoid coil 24 is adjusted to the current value i3 (A) so as to be / cm ² G, since the electromagnetic force generated by the electromagnetic device 20 is larger than the urging force of the spring member 14, the valve 18 is As shown in (2), the crank chamber pressure is reduced to become equal to the suction chamber pressure, so that the compressor is maintained at the maximum capacity and the suction chamber pressure gradually decreases.

As the suction chamber pressure decreases, the bellows 12
Extend, and the lower end of the guide 13 in the figure comes into contact with the bottom of the valve casing 11, so that the function of the spring member 14 is lost. At this time, the force due to the crank chamber pressure acting on the valve body 18 is the surface 1
Since the discharge chamber pressure does not act on the valve body 18 in the axial direction, the valve body 18 is opened and closed according to the electromagnetic force and the suction chamber pressure acting on the bellows 12. That is, when the suction chamber pressure decreases to ² kg / cm ² G, the bellows 12 expands, and as shown in FIG.
8 operates in the opening direction, the gas in the discharge chamber 52 is introduced into the crank chamber 43, and the discharge capacity decreases due to the increase in the pressure difference between the crank chamber 43 and the suction chamber 51. As a result, when the suction chamber pressure increases, the bellows 12 contracts and the valve body 18 operates in the closing direction as shown in FIG. 4, so that the crank chamber pressure decreases, and the pressure difference between the crank chamber 43 and the suction chamber 51 decreases. Due to the decrease, the discharge capacity increases.

In this way, the opening of the valve element 18 is adjusted so that the suction chamber pressure becomes a predetermined value, and the discharge capacity is controlled. Therefore, as shown in FIG. 6, the control point of the suction chamber pressure is uniquely determined by the current value. When the current value is reduced to zero from this state, the bellows 12 is extended, the valve element 18 is fully opened, and the pressure difference between the crank chamber 43 and the suction chamber 51 is significantly increased. As a result, even if the suction chamber pressure rises to 3.5 kg / cm ² G or more in FIG. 6 and the bellows 12 contracts, the valve
Is urged upward in the figure by the spring member 14,
The valve element 18 is always opened and is maintained at the minimum capacity.

[0035]

As described above, according to the present invention,
A capacity control valve configured such that the suction chamber pressure control point is uniquely determined with respect to the amount of power supplied to the electromagnetic device, and the variable capacity compressor can be forcibly maintained at a minimum capacity in a state where power is not supplied; and A variable displacement compressor provided with the compressor can be provided. In particular, since the valve body can be reduced in weight and the seal diameter of the valve body can be increased, the responsiveness of the displacement control valve is improved. Further, even when the valve is closed, the external force applying mechanism and the pressure-sensitive member are interlocked, so that a smooth operation can be obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a displacement control valve according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a variable displacement compressor provided with the displacement control valve of FIG.

FIG. 3 is a longitudinal sectional view showing a state where power is not supplied to a solenoid coil of the displacement control valve of FIG. 1;

FIG. 4 is a longitudinal sectional view showing a state in which the solenoid coil of the displacement control valve of FIG. 1 is energized and is closed.

FIG. 5 is a longitudinal sectional view showing a state in which the solenoid coil of the displacement control valve in FIG. 1 is energized and is opened.

FIG. 6 is a graph showing pressure control characteristics of the displacement control valve of FIG. 1;

FIG. 7 is a longitudinal sectional view of a conventional capacity control valve.

FIG. 8 is a graph showing pressure control characteristics of the capacity control valve of FIG. 7;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Capacity control valve 11 Valve casing 12 Bellows 13 Guide 14 Spring member 15 Pressure sensing rod 16 Valve room 17a, 17b Communication path 18 Valve element 19 Spring member 20 Electromagnetic device 21 Through hole 22 Balance chamber 24 Solenoid coil 26 Plunger 27 Solenoid rod 37 Shaft 43 Crank chamber 44 Rotor 45 Hinge mechanism 46 Swash plate 47 Piston 48 Cylinder bore 51 Suction chamber 52 Discharge chamber

Claims (6)

[Claims] 1. A valve body movable in a predetermined direction for opening and closing a communication path for communicating a discharge chamber and a crank chamber of a variable displacement compressor, and a valve body disposed on one side of the valve body in the predetermined direction, and A pressure-sensitive member that senses the reference pressure and expands and contracts in the predetermined direction to drive the valve element, and is disposed on the other side of the valve element in the predetermined direction, and applies an external force in the predetermined direction to the pressure-sensitive member. A capacity control valve provided with an external force applying mechanism for performing
The capacity control valve, wherein the valve body has a through hole penetrating in the predetermined direction, and the external force applying mechanism is inserted into the through hole and engaged with the pressure-sensitive member. 2. The external force applying mechanism includes a solenoid coil controlled to be energized and de-energized, and a solenoid rod driven by an electromagnetic force of the solenoid coil.
2. The displacement control valve according to claim 1, wherein the solenoid rod is engaged with the pressure-sensitive member through the through hole, and when the solenoid coil is energized, the solenoid rod presses and contracts the pressure-sensitive member in the predetermined direction. . 3. The displacement control valve according to claim 1, further comprising a balance chamber communicating with the through hole and acting on the valve body to balance gas pressure in the predetermined direction. A first spring member for urging the valve body in a closing direction with a first urging force, wherein the pressure-sensitive member drives the valve body in an opening direction when extended. The capacity control valve according to claim 1. 5. A valve casing accommodating the pressure-sensitive member movably in the predetermined direction, and a second urging force larger than the first urging force, the pressure-sensitive member being connected to the valve body. The capacity control valve according to claim 4, further comprising a second spring member biased in an opening direction. 6. A variable displacement compressor having a discharge chamber, a crank chamber, and a communication passage communicating therewith, comprising a displacement control valve according to claim 1, wherein the displacement control valve is provided by the displacement control valve. A variable displacement compressor, wherein opening and closing of the communication passage is controlled.