Seal structure for a rotary valve compressor

Abstract

A variable displacement compressor includes a rotary valve coupled to a drive shaft of the compressor and configured to selectively permit fluid communication between a suction chamber and cylinders of the compressor. An annular seal is disposed adjacent the rotary valve and engages at least a portion of a wall defining the suction chamber and a surface of the rotary valve.

Description

FIELD OF THE INVENTION[0001]The present invention relates to a variable displacement compressor for use in an air conditioning system for a vehicle, and more particularly to a seal structure for a variable displacement compressor having a rotary valve for supplying a refrigerant gas into a cylinder to be compressed.BACKGROUND OF THE INVENTION[0002]As commonly known, variable displacement compressors having a swash plate are used in air conditioning systems of motor vehicles. Such compressors typically include at least one piston disposed in a cylinder of a cylinder block and a rotor assembly operatively coupled to a drive shaft. The swash plate is coupled to and caused to rotate by the rotor assembly. The swash plate is variably angled relative to the rotor between a minimum angle and a maximum angle. Each piston slidably engages with the swash plate through a shoe as the swash plate rotates causing the piston to reciprocate within the cylinder. As the angle of the swash plate relat...

AI Technical Summary

Benefits of technology

The present invention has discovered a rotary valve structure that can maintain a high flow of refrigerant gas while minimizing the space left in the compressor. This structure also has good thermal properties, durability, balance, sealing abilities, and features that make it highly efficient.

Problems solved by technology

However, certain disadvantages are encountered with the use of reed valves.

Specifically, the suction reed cannot open properly unless a pressure difference between the cylinder and the suction chamber is sufficient to overcome the spring force thereof.

Moreover, oil in the compressor can cause the reed valves to stick.

Additionally, due to a geometry and a maximum bending stress of the reed valves, the flow area of the refrigerant gas through the suction port and discharge port is limited.

Furthermore, because the reed valves often do not open or close properly due to at least the above reasons, the reed valves begin to “float.” Floating causes improper sealing and internal leakage.

However, these valve structures do not provide a maximum suction flow of the refrigerant gas and / or provide an increase in a dead volume ratio when the compressor is in a variable displacement mode.

Additional disadvantages include poor sealing of and undesired leakage of the refrigerant gas to undesired areas of the compressor.

Furthermore, the rotary valve structures do not provide desired thermal properties, durability, balance, and bearing properties to minimize deflections thereof and operatively maintain desired efficiency of the compressor.

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