Compressor pistons and compressors including such pistons

Abstract

A compressor may include a cylinder block having a plurality of cylinder bores formed therethrough, a drive shaft rotatably supported by the cylinder block, and a swash plate rotatably mounted on said drive shaft. The compressor also may include a plurality of pistons, and each of the cylinder bores may have an outer radial edge. Moreover, each of the pistons may include a head portion which is slidably inserted inside one of the cylinder bores, and a skirt portion which extends from an end surface of the head portion, in which the skirt portion includes a pair of shoe receiving portions. Each piston also may include a rotation prevention portion which is formed at the skirt portion and prevents the piston from rotating about its axis. Moreover, a first separation distance between an axis of rotation of the swash plate and an abutment portion of the rotation prevention portion which slidably abuts an interior wall of a compressor housing is less than a second separation distance between the axis of rotation of the swash plate and a portion of the outer radial edge which edge is furthest from the axis of rotation of the swash plate.

What is claimed is:  
     
         1 . A piston for use in a compressor, comprising: 
 a head portion which is slidably inserted inside a cylinder bore, wherein the cylinder bore has an outer radial edge;    a skirt portion which extends from an end surface of the head portion, and comprises a pair of shoe receiving portions; and    a rotation prevention portion which is formed at the skirt portion and prevents the piston from rotating about its axis, wherein a first separation distance between an axis of rotation of a swash plate and an abutment portion of the rotation prevention portion which slidably abuts an interior wall of a compressor housing is less than a second separation distance between the axis of rotation of the swash plate and a portion of the outer radial edge which edge is furthest from the axis of rotation of the swash plate.    
     
     
         2 . The piston of  claim 1 , wherein said abutment portion has a pair of projection portions extending from said shoe receiving portion.  
     
     
         3 . The piston of  claim 2 , wherein the projection portions comprise a curved surface.  
     
     
         4 . The piston of  claim 3 , wherein the curved surface comprises a pair of concave portions, and a convex portion which is positioned between the concave portions.  
     
     
         5 . A compressor, comprising: 
 a cylinder block having a plurality of cylinder bores formed therethrough, wherein each of the cylinder bores has an outer edge;    a drive shaft rotatably supported by the cylinder block;    a swash plate rotatably mounted on said drive shaft; and    a plurality of pistons, wherein each of the pistons comprise: 
 a head portion which is slidably inserted inside one of the cylinder bores;  
 a skirt portion which extends from an end surface of the head portion, and comprises a pair of shoe receiving portions; and  
 a rotation prevention portion which is formed at the skirt portion and prevents the piston from rotating about its axis, wherein a first separation distance between an axis of rotation of the swash plate and an abutment portion of the rotation prevention portion which slidably abuts an interior wall of a compressor housing is less than a second separation distance between the axis of rotation of the swash plate and a portion of the outer radial edge which edge is furthest from the axis of rotation of the swash plate.  
   
     
     
         6 . The compressor of  claim 5 , wherein said abutment portion has a pair of projection portions extending from said shoe receiving portion.  
     
     
         7 . The compressor of  claim 6 , wherein the projection portions comprise a curved surface.  
     
     
         8 . The compressor of  claim 7 , wherein the curved surface comprises a pair of concave portions, and a convex portion which is positioned between the concave portions.  
     
     
         9 . A piston for use in a compressor, comprising: 
 a head portion which is slidably inserted inside a cylinder bore, wherein the cylinder bore has an outer radial edge;    a skirt portion which extends from an end surface of the head portion, and comprises a pair of shoe receiving portions; and    a rotation prevention portion which is formed at the skirt portion and prevents the piston from rotating about its axis, wherein a separation distance between an axis of rotation of a swash plate and an abutment portion of the rotation prevention portion which slidably abuts an interior wall of a compressor housing is less than a radius of an arc which includes a portion of the outer radial edge which edge is furthest from the axis of rotation of the swash plate.    
     
     
         10 . The piston of  claim 9 , wherein said abutment portion has a pair of projection portions extending from said shoe receiving portion.  
     
     
         11 . The piston of  claim 10 , wherein the projection portions comprise a curved surface.  
     
     
         12 . The piston of  claim 11 , wherein the curved surface comprises a pair of concave portions, and a convex portion which is positioned between the concave portions.  
     
     
         13 . A compressor, comprising: 
 a cylinder block having a plurality of cylinder bores formed therethrough, wherein each of the cylinder bores has an outer edge;    a drive shaft rotatably supported by the cylinder block;    a swash plate rotatably mounted on said drive shaft; and    a plurality of pistons, wherein each of the pistons comprise: 
 a head portion which is slidably inserted inside one of the cylinder bores, wherein each of the cylinder bores has an outer radial edge;  
 a skirt portion which extends from an end surface of the head portion, and comprises a pair of shoe receiving portions; and  
 a rotation prevention portion which is formed at the skirt portion and prevents the piston from rotating about its axis, wherein a separation distance between an axis of rotation of a swash plate and an abutment portion of the rotation prevention portion which slidably abuts an interior wall of a compressor housing is less than a radius of an arc which includes a portion of the outer radial edge which is furthest from the axis of rotation of the swash plate.  
   
     
     
         14 . The compressor of  claim 13 , wherein said abutment portion has a pair of projection portions extending from said shoe receiving portion.  
     
     
         15 . The compressor of  claim 14 , wherein the projection portions comprise a curved surface.  
     
     
         16 . The compressor of  claim 15 , wherein the curved surface comprises a pair of concave portions, and a convex portion which is positioned between the concave portions.