Variable displacement compressor

Abstract

A variable displacement compressor comprising a cylinder block having a plurality of cylinder bores. The cylinder block has an extension which extends from an outer periphery of an end surface of the cylinder block which faces a swash plate. The extension has an extension surface which forms a part of a bore surface of each cylinder bore and first and second wall surfaces which extend continuously from opposite ends of the extension surface in a circumferential direction of the extension surface. A part of each extension surface which is connected to the first wall surface which is located on a preceding side of rotation of the swash plate corresponds to a high-load area which is locally subjected to loads from a single-headed piston during a compression stroke. The high-load area has a chamfered region which is formed into a curved surface by chamfering.

1 . A variable displacement compressor comprising:
 a cylinder block having a plurality of cylinder bores;   a rotary shaft rotatably supported by the cylinder block;   a swash plate provided on the rotary shaft for rotation therewith;   a plurality of single-headed pistons engaged with the swash plate for reciprocation in the cylinder bores; and   a diameter expansion surface formed at an edge of a bore surface of each cylinder bore which faces the swash plate so that a diameter of an opening of the cylinder bore are extended,   wherein the cylinder block has an extension which extends from an outer periphery of an end surface of the cylinder block which faces the swash plate,   wherein the extension has an extension surface which forms a part of the bore surface of each cylinder bore and first and second wall surfaces which extend continuously from opposite ends of the extension surface in a circumferential direction of the extension surface,   wherein a part of each extension surface which is connected to the first wall surface which is located on a preceding side of rotation of the swash plate corresponds to a high-load area which is locally subjected to loads from the piston during a compression stroke, and   wherein the high-load area has a chamfered region which is formed into a curved surface by chamfering.   
   
   
       2 . The variable displacement compressor according to  claim 1 , wherein the chamfered region has a curved surface which is formed in a circumferential direction and a longitudinal direction of the cylinder bore. 
   
   
       3 . The variable displacement compressor according to  claim 1 , wherein the chamfered region has a part of the diameter expansion surface which is located in the high-load area. 
   
   
       4 . The variable displacement compressor according to  claim 1 , wherein the chamfered region includes a first region which is formed an edge between the extension surface and the diameter expansion surface in the high-load area into a curved surface by chamfering. 
   
   
       5 . The variable displacement compressor according to  claim 1 , wherein a chamfered surface is formed between the extension surface and the first wall surface so as to be inclined relative to the extension surface. 
   
   
       6 . The variable displacement compressor according to  claim 5 , wherein the chamfered region includes a second region which is formed an edge between the diameter expansion surface and the chamfered surface into a curved surface by chamfering. 
   
   
       7 . The variable displacement compressor according to  claim 5 , wherein the chamfered region includes a third region which is formed an edge between the extension surface and the chamfered surface into a curved surface by chamfering. 
   
   
       8 . The variable displacement compressor according to  claim 1 , wherein the chamfered region includes a fourth region which is formed an edge between the extension surface and the first wall surface into a curved surface by chamfering. 
   
   
       9 . The variable displacement compressor according to  claim 1 , wherein a beveled surface is formed between the first wall surface and an end surface of the extension which faces the swash plate. 
   
   
       10 . The variable displacement compressor according to  claim 1 , wherein a beveled surface is formed between the second wall surface and an end surface of the extension which faces the swash plate. 
   
   
       11 . The variable displacement compressor according to  claim 1 , wherein the diameter expansion surface includes a beveled surface which is formed between the extension surface and an end surface of the extension which faces the swash plate. 
   
   
       12 . The variable displacement compressor according to  claim 11 , wherein the diameter expansion surface includes a beveled surface which is formed between the end surface of the cylinder block and the bore surface of the cylinder bore.