CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Phase under 35 U.S.C. § 371 of International Application PCT/JP2018/025123, filed Jul. 3, 2018, which claims priority to Japanese Patent Application No. JP2017-133157, filed Jul. 6, 2017. The International Application was published under PCT Article 21(2) in a language other than English.

TECHNICAL FIELD

The present invention relates to a capacity control valve for controlling a flow rate or pressure of a variable capacity compressor, and, particularly, relates to a capacity control valve for controlling a discharge rate of a variable capacity compressor and the like used for an air-conditioning system for motor vehicle and the like according to a pressure load.

BACKGROUND ART

A swash plate type variable capacity compressor used for an air-conditioning system for motor vehicle and the like includes a rotating shaft rotationally driven by the rotational force of an engine, a swash plate which is coupled to the rotating shaft so that its inclination angle may be varied, a piston for compression coupled to the swash plate, and the like, and changes the inclination angle of the swash plate, thereby changing a stroke of the piston and controlling a discharge rate of a refrigerant.

By appropriately controlling pressure within a control chamber and adjusting a balancing state of the pressure acting on the both surfaces of the piston by means of a capacity control valve which is driven to be opened or closed by electromagnetic force while utilizing a suction pressure of a suction chamber for suctioning a refrigerant, a discharge pressure of a discharge chamber for discharging the refrigerant pressurized by the piston, and a control chamber pressure of the control chamber (a crank chamber) containing the swash plate, the inclination angle of the swash plate can continuously change the stroke of the piston.

As shown inFIG. 6, such a capacity control valve160includes: a valve section170having a second valve chamber182communicating with a discharge chamber via a second communication passage173, a first valve chamber183communicating with a suction chamber via a first communication passage171, and a third valve chamber184communicating with a control chamber via a third communication passage174; a pressure-sensitive body178which is arranged in the third valve chamber to extend and contract by ambient pressure and which has a valve seat body180provided at a free end in an extension and contraction direction; a valve body181having a second valve part176for opening and closing a valve hole177for communicating the second valve chamber182and the third valve chamber184, a first valve part175for opening and closing the first communication passage171and a circulation groove172, and a third valve part179for opening and closing the third valve chamber184and the circulation groove172by engagement and disengagement to and from the valve seat body180in the third valve chamber184; a solenoid section190for exerting an electromagnetic driving force on the valve body181, and the like. Then, in the control capacity valve160, without providing a clutch mechanism in a variable capacity compressor, a pressure in the control chamber (a control chamber pressure) Pc and a suction pressure Ps (a suction pressure) can be adjusted by communicating the discharge chamber and the control chamber in a case where the need to change the control chamber pressure arises (Hereinafter, it is referred to as a “conventional art”. For example, see Patent Document 1.).

CITATION LIST

Patent Documents

Patent Document 1: JP 5167121 B

SUMMARY OF THE INVENTION

Problem to be Solved by the Invention

In the conventional art, if the swash plate type variable capacity compressor is stopped and then is intended to be started after a long-time standing, a liquid refrigerant (the refrigerant which is liquefied by being cooled during standing) is accumulated in the control chamber (crank chamber), and therefore it is impossible to secure a set discharge rate by compressing the refrigerant unless the liquid refrigerant is discharged. Therefore, in order to perform a desired capacity control just after start-up, the liquid refrigerant in the control chamber (crank chamber) needs to be discharged as quickly as possible.

Thus, as shown inFIG. 7andFIG. 8, the conventional capacity control valve160includes a liquid refrigerant discharge function in order to discharge the liquid refrigerant in the control chamber (crank chamber) as quickly as possible at the time of start-up. That is, if the variable capacity compressor is stopped and then is intended to be started after a long-time standing, high-pressure liquid refrigerant accumulated in the control chamber (crank chamber) flows into the third valve chamber184from the third communication passage174. Then, the pressure-sensitive body (bellows)178contracts and the third valve part179and the valve seat body180are opened therebetween. An opening area between the third valve part179and the valve seat body180is large, and therefore the liquid refrigerant can be discharged to the suction chamber out of the control chamber (crank chamber) in a short time, through the auxiliary communication passage185, the intermediate communication passage186and the circulation groove172from the third valve chamber184, thereby capable of quickly shifting to a cooling operation state at maximum capacity.

Subsequently, when discharge of the liquid refrigerant in the control chamber (crank chamber) is finished, the control chamber pressure Pc and the suction pressure Ps are decreased, and the third valve part179and the valve seat body180are closed therebetween. At the same time, the second valve part176is opened from a fully closed state by the solenoid section S and shifts to a control state. When shifted to the control state, the fluid at the discharge pressure Pd is supplied to the third valve chamber184from the second valve chamber182, and thereby a differential pressure between the suction pressure Ps and the control chamber pressure Pc is changed, an inclination angle of the swash plate is changed, and a stroke (discharge capacity) of a piston is controlled.

However, in the above-described conventional art, even if a control operation begins and the third valve part179and the valve seat surface of the valve seat body180are closed therebetween, a little gap is generated between the third valve part179and the valve seat body180when the pressure of the third valve chamber184is fluctuated. Therefore, the fluid volume flowing to the first valve chamber183via the auxiliary communication passage185and the intermediate communication passage186from the third valve chamber184is fluctuated. As a result, the pressure of the suction chamber communicating with the first valve chamber183is fluctuated, and thus there was a problem that a control performance of the variable capacity compressor is deteriorated.

The present invention has been made to solve the problems the above-described conventional art has, and an object thereof is to provide a capacity control valve for controlling a flow rate or pressure of a variable capacity compressor according to a valve opening degree of a valve main body, the capacity control valve capable of making constant a fluid volume flowing to a first valve chamber from a third valve chamber even if the pressure of the third valve chamber is fluctuated and capable of improving a control performance of the variable capacity compressor.

Means for Solving Problem

To attain the above object, a capacity control valve according to a first aspect of the present invention is a capacity control valve for controlling a flow rate or pressure according to a valve opening degree of a valve section, the capacity control valve including:

a valve main body having an interior space communicating with a third communication passage through which a fluid at a control pressure passes, a second valve chamber communicating with a second communication passage through which a fluid at discharge pressure passes and having a valve hole communicating with the interior space and a second valve seat arranged in the valve hole, and a first valve chamber communicating with a first communication passage through which a fluid at a suction pressure passes and having a first valve seat;

a valve body having an intermediate communication passage communicating with the interior space and the first communication passage, a second valve part for opening and closing the valve hole by separating from and making contact with the second valve seat, a first valve part which performs opening/closing action in reverse association with the second valve part and which opens and closes communication between the intermediate communication passage and the first communication passage by separating from and making contact with the first valve seat, and a shaft part arranged in the interior space;

a pressure-sensitive body which is arranged in the interior space and extends and contracts in response to the pressure of the interior space and which has a free end part sliding with the shaft part of the valve body;

an auxiliary communication part which is arranged in the interior space and which allows communication between the interior space and the intermediate communication passage; and

a solenoid section which is mounted to the valve main body and actuates the valve body to opening/closing direction according to current.

According to the first aspect, a fluid volume flowing to the first valve chamber from the interior space is adjusted by the auxiliary communication part arranged in the interior space, thereby capable of improving operation efficiency of a variable capacity compressor.

In the capacity control valve according to a second aspect of the present invention, the auxiliary communication part has an opening area smaller than a flow passage cross-sectional area of the intermediate communication passage.

According to the second aspect, the auxiliary communication part serves as a bottleneck, and therefore the fluid flowing to the first valve chamber from the interior space is adjusted by adjusting only the auxiliary communication passage, thereby capable of improving operation efficiency of the variable capacity compressor.

In the capacity control valve according to a third aspect of the present invention, the auxiliary communication part is a hole part arranged in the valve body.

According to the third aspect, the opening area of the auxiliary communication part can be adjusted by adjusting the diameter of the hole part.

In the capacity control valve according to a fourth aspect of the present invention, the auxiliary communication part has an opening area larger than a gap part between the shaft part of the valve body and the free end part of the pressure-sensitive body.

According to the fourth aspect, even if flow passages leading to the first valve chamber from the interior space exist in parallel to each other, the fluid volume flowing to the first valve chamber from the interior space can be adjusted by adjusting only the auxiliary communication part.

In the capacity control valve according to a fifth aspect of the present invention, the valve body includes a plurality of the auxiliary communication parts.

According to the fifth aspect, the opening area of the auxiliary communication parts can be adjusted by adjusting the number of the auxiliary communication parts.

In the capacity control valve according to a sixth aspect of the present invention, the auxiliary communication part is made up of a gap part between the shaft part of the valve body and the free end part of the pressure-sensitive body.

According to the sixth aspect, the fluid volume flowing to the first valve chamber from the interior space is adjusted by adjusting the gap part between the shaft part of the valve body and the free end part of the pressure-sensitive body, thereby capable of improving operation efficiency of the variable capacity compressor.

