Swash plate type compressor

Abstract

A swash plate type compressor 1 arranged with a swash plate 3 which rotates around a shaft 2, a piston 4 which moves back and forth with the rotation of the swash plate 3 and formed with a spherical indent part 4 a, and a shoe 5 formed with a flat part 5 a which slides against the swash plate 3 and a spherical surface part 5 b which slides in the spherical indent part 4 a formed on the piston 4, wherein a coating layer 3 b comprised s formed on the surface of the swash plate 3 and spiral or concentric shaped grooves 3 c are formed with the center of the swash plate 3 at the center on the surface of the coating layer 3 b, a diameter of the flat part 3 is set at 10.5 mm or less, and the pitch of the concentric protrusion 3 d is set so that the sum of the length of the concentric protrusions 3 d which contact the flat part 5 a is 300 mm or more. It is possible to reduce friction between the shoe and the swash plate by reducing the diameter of the flat part of the shoe and it is possible to reduce wear of the coating layer.

What is claimed is: 
     
         1 . A swash plate type compressor comprising:
 a swash plate which rotates around a shaft;   a piston formed with a spherical indent part and which moves back and forth with the rotation of the swash plate; and   a shoe formed with a flat part which slides against the swash plate and a spherical surface part which slides in the spherical indent part formed on the piston;   wherein   a coating layer comprised from a resin is formed on the surface of the swash plate, and spiral or concentric shaped grooves are formed with the center of the swash plate at the center on the surface of the coating layer, a diameter of the flat part is set at less than 10.5 mm and the pitch of a concentric protrusion formed between the concentric shaped grooves is set to satisfy the following conditions:   
       
         
           
             
               
                 
                   
                     
                       
                         ∑ 
                         
                           k 
                           = 
                           1 
                         
                         N 
                       
                        
                       
                         L 
                         k 
                       
                     
                     > 
                     
                       300 
                        
                       
                         ( 
                         mm 
                         ) 
                       
                     
                   
                 
                 
                   
                     [ 
                     
                       Formula 
                        
                       
                           
                       
                        
                       1 
                     
                     ] 
                   
                 
               
             
           
         
       
       L=length (mm) of the concentric protrusion which contact the flat part of the shoe, 
       N=number of concentric protrusions which contact the flat part of the shoe. 
     
     
         2 . The swash plate type compressor according to  claim 1 , wherein a taper part is formed so as to surround the flat part and the flat part and the taper part are connected by a smooth surface.