Scroll compressor

Abstract

A compressor includes a housing, a fixed scroll, a movable scroll and a control valve. The housing has a suction chamber, a discharge chamber and a backpressure chamber formed therein. The scrolls are pressed against each other by backpressure in the backpressure chamber. The control valve for controlling the backpressure has first, second and third chambers arranged in this order. The first, second and third chambers are connected to the discharge chamber, the backpressure chamber and the suction chamber, respectively. The control valve has a valve member. The valve member has a first pressure-receiving surface located in the first chamber, a second pressure-receiving surface located in the second chamber and a third pressure-receiving surface located in the third chamber. The area of the third pressure-receiving surface is larger than the area of the first pressure-receiving surface and larger than the area of the second pressure-receiving surface.

1 . A scroll compressor, comprising:
 a housing having a suction chamber, a discharge chamber and a backpressure chamber formed therein;   a fixed scroll accommodated in the housing;   a movable scroll accommodated in the housing, the movable scroll cooperating with the fixed scroll to form therebetween a compression chamber, the movable scroll and the fixed scroll being pressed against each other by backpressure in the backpressure chamber; and   a control valve for controlling the backpressure in the backpressure chamber by communication with the suction chamber, the discharge chamber or the compression chamber,   wherein the control valve has a first chamber, a second chamber and a third chamber arranged in this order, the first chamber being connected to the discharge chamber or the compression chamber, the second chamber being connected to the backpressure chamber, the third chamber being connected to the suction chamber,   wherein the control valve has a valve member, the valve member having a first pressure-receiving surface located in the first chamber, a second pressure-receiving surface located in the second chamber and a third pressure-receiving surface located in the third chamber,   wherein the area of the third pressure-receiving surface is larger than the area of the first pressure-receiving surface and larger than the area of the second pressure-receiving surface.   
     
     
         2 . The scroll compressor according to  claim 1 , wherein the control valve has a valve seat associated with the valve member and provided between the second chamber and the third chamber, and the control valve is controllable to the communication between the backpressure chamber and the suction chamber. 
     
     
         3 . The scroll compressor according to  claim 2 , wherein the backpressure chamber is connected to the discharge chamber through a throttle. 
     
     
         4 . The scroll compressor according to  claim 2 , wherein the valve member includes a tapered portion facing the valve seat and tapered to the second chamber. 
     
     
         5 . The scroll compressor according to  claim 4 , wherein the tapered portion is located across the second chamber and the third chamber. 
     
     
         6 . The scroll compressor according to  claim 4 , wherein the valve member has cylindrical shape with the tapered portion, the valve member has an end surface located in the first chamber to form the first pressure-receiving surface, the valve member has an end surface located in the third chamber to form the third pressure-receiving surface, and the tapered portion is located in the second chamber to form the second pressure-receiving surface. 
     
     
         7 . The scroll compressor according to  claim 5 , wherein the area of the second pressure-receiving surface corresponds to the area of the tapered portion located in the second chamber in axial direction of the valve member. 
     
     
         8 . The scroll compressor according to  claim 1 , wherein the control valve has a valve seat associated with the valve member and provided between the first chamber and the second chamber, and the control valve is controllable to the communication between the discharge chamber and the backpressure chamber. 
     
     
         9 . The scroll compressor according to  claim 8 , wherein the backpressure chamber is connected to the suction chamber through a throttle. 
     
     
         10 . The scroll compressor according to  claim 8 , wherein the valve member includes a tapered portion facing the valve seat and tapered to the second chamber, and the tapered portion is located across the first chamber and the second chamber.