Displacement control valve of variable displacement compressor

Abstract

A displacement control valve includes an electromagnetic solenoid and a drive force transmitting body. A pressure sensing chamber communicates with a suction chamber and a pressure sensing body is located in the pressure sensing chamber. An internal passage is provided in the transmitting body and an external passage is provided about the transmitting body. The first to third valve bodies are provided at the transmitting body. The first valve body adjusts a cross-sectional area of a passage between the external passage and the internal passage. The second valve body adjusts a cross-sectional area of a passage between the internal passage and the pressure sensing chamber. The third valve body adjusts a cross-sectional area of a passage between the external passage and a discharge chamber. The transmitting body is switched among first, second, and third arrangement states by the electromagnetic solenoid. With the transmitting body at the first arrangement state, the third valve body is at an open position when the first valve body is at a closed position. With the transmitting body at the second arrangement state, the first valve body is at an open position when the third valve body is at a closed position. With the transmitting body at the third arrangement state, both of the first and third valve bodies are at the open position.

1 . A displacement control valve of a variable displacement compressor, wherein the compressor draws refrigerant from a suction pressure zone and discharges the refrigerant to a discharge pressure zone, and controls displacement according to a pressure in a control pressure chamber, the displacement control valve comprising:
 an electromagnetic solenoid;   a drive force transmitting body movable along a movement axis, the drive force transmitting body receiving, from the electromagnetic solenoid, a drive force in a drive direction along the movement axis;   a pressure sensing portion having a pressure sensing chamber that communicates with the suction pressure zone and a pressure sensing body that receives a pressure in the pressure sensing chamber, wherein the pressure sensing body is urged in the drive direction by the pressure in the pressure sensing chamber, the position of the pressure sensing body in a direction along the movement axis is regulated in accordance with the pressure in the pressure sensing chamber;   an internal passage provided in the drive force transmitting body, the internal passage being connectable to the pressure sensing chamber;   an external passage provided about the drive force transmitting body, the external passage being connected to the control pressure chamber;   a first valve body provided at the drive force transmitting body, the first valve body adjusting a cross-sectional area of a passage between the external passage and the internal passage;   a second valve body contactable with and separable from the pressure sensing body, the second valve body adjusting a cross-sectional area of a passage between the internal passage and the pressure sensing chamber; and   a third valve body provided at the drive force transmitting body, the third valve body adjusting a cross-sectional area of a passage between the external passage and the discharge pressure zone,   wherein the drive force transmitting body is switched among first, second, and third arrangement states by the electromagnetic solenoid, wherein, with the drive force transmitting body at the first arrangement state, the third valve body is at an open position when the first valve body is at a closed position, wherein, with the drive force transmitting body at the second arrangement state, the first valve body is at an open position when the third valve body is at a closed position, and wherein, with the drive force transmitting body at the third arrangement state, both of the first and third valve bodies are at the open position.   
   
   
       2 . The displacement control valve according to  claim 1 , wherein the first valve body, the third valve body, and the second valve body are arranged in this order from a side corresponding to the electromagnetic solenoid toward a side corresponding to the pressure sensing portion, wherein the displacement control valve has a valve hole that slidably receives the drive force transmitting body, wherein a groove passage is formed in an circumferential surface of the drive force transmitting body between the second valve body and the third valve body, the groove passage being capable of connecting the discharge pressure zone and the external passage to each other, and wherein the third valve body adjusts a cross-sectional area of a passage between the groove passage and the external passage. 
   
   
       3 . The displacement control valve according to  claim 2 , further comprising a partition wall that separates the pressure sensing chamber and the external passage from each other, wherein the valve hole extends through the partition wall, and wherein the third valve body is contactable with and separable from a seat surface of the partition wall provided about the opening of the valve hole. 
   
   
       4 . The displacement control valve according to  claim 3 , wherein the first and third valve bodies are located in the external passage, and wherein the second valve body is located in the pressure sensing chamber. 
   
   
       5 . The displacement control valve according to  claim 2 , wherein the drive force transmitting body includes a shaft body having the internal passage and a cylindrical body fixed to the shaft body, wherein the second valve body and the third valve body are formed in the shaft body, and the first valve body is formed in the cylindrical body. 
   
   
       6 . The displacement control valve according to  claim 1 , wherein a pressure receiving area in the drive direction of the pressure sensing body is larger than a closed area of the second valve body. 
   
   
       7 . The displacement control valve according to  claim 1 , wherein the pressure sensing body includes a bellows. 
   
   
       8 . The displacement control valve according to  claim 1 , wherein the compressor includes a supply passage for supplying refrigerant in the discharge pressure zone to the control pressure chamber, and a discharge passage for discharging refrigerant in the control pressure chamber to the suction pressure zone, wherein the internal passage forms a part of the discharge passage, and wherein the external passage forms a part of the supply passage and a part of the discharge passage. 
   
   
       9 . A variable displacement compressor comprising:
 the displacement control valve according to  claim 1 ; and   a bleed passage connecting the control pressure chamber and the suction pressure zone to each other.   
   
   
       10 . A displacement control valve of a variable displacement compressor, wherein the compressor draws refrigerant from a suction pressure zone and discharges the refrigerant to a discharge pressure zone, and controls displacement according to a pressure in a control pressure chamber, the displacement control valve comprising:
 an electromagnetic solenoid;   a drive force transmitting body movable along a movement axis, the drive force transmitting body being driven by the electromagnetic solenoid, wherein electromagnetic force generated by the electromagnetic solenoid applies, to the drive force transmitting body, a drive force in a drive direction along the movement axis;   a pressure sensing portion having a pressure sensing chamber that communicates with the suction pressure zone and a pressure sensing body that receives a pressure in the pressure sensing chamber, wherein the pressure sensing body is urged in the drive direction by the pressure in the pressure sensing chamber, and is displaced in a direction along the movement axis in accordance with the pressure in the pressure sensing chamber;   an external passage provided abount the drive force transmitting body, the external passage being connected to the control pressure chamber;   a partition wall that separates the pressure sensing chamber and the external passage from each other, the partition wall having a valve hole that permits the drive force transmitting body to pass therethrough, wherein the valve hole communicates with the discharge pressure zone;   an internal passage provided in the drive force transmitting body, the internal passage being capable of connecting the pressure sensing chamber to the external passage;   a first valve body provided at the drive force transmitting body, the first valve body adjusting a cross-sectional area of a passage between the external passage and the internal passage;   a second valve body provided at the drive force transmitting body, wherein the second valve body is contactable with and separable from the pressure sensing body, and adjusts a cross-sectional area of a passage between the internal passage and the pressure sensing chamber; and   a third valve body provided at the drive force transmitting body, the third valve body adjusting a cross-sectional area of a passage between the external passage and the valve hole,   wherein the drive force transmitting body is switched among first, second, and third arrangement states by the electromagnetic solenoid, wherein, with the drive force transmitting body at the first arrangement state, the third valve body is at an open position when the first valve body is at a closed position, wherein, with the drive force transmitting body at the second arrangement state, the first valve body is at an open position when the third valve body is at a closed position, and wherein, with the drive force transmitting body at the third arrangement state, both of the first and third valve bodies are at the open position.