Compressors and pistons for use in such compressors

Abstract

A piston for use in a compressor comprises a head portion and an engaging portion. The engaging portion includes a first shoe pocket and a second shoe pocket formed therein, and an interior surface of the first shoe pocket includes a hollow potion formed therein. Moreover, the interior surface of the first shoe pocket includes a lubrication layer formed thereon. For example, the lubricant layer may include a solid lubricant or a grease having a viscosity which is sufficient to adhere the grease to the interior surface of the first shoe pocket or the second shoe pocket, or both. In an embodiment, an interior surface of the second shoe pocket also may have the hollow portion formed therein. In another embodiment, the interior surface of the second shoe pocket may have a penetrating aperture formed therein.

What is claimed is:  
     
         1 . A compressor for use in an automotive air conditioning system comprising: 
 a front housing    a cylinder block comprising at least one cylinder bore formed therethrough;    a drive shaft rotatably supported by the cylinder block and the front housing;    a swash plate rotatably mounted on the drive shaft;    at least one piston positioned within the at least one cylinder bore, wherein the at least one piston comprises: 
 a head portion; and  
 an engaging portion comprising a first shoe pocket and a second shoe pocket formed therein,, wherein an interior surface of the first shoe pocket comprises: 
 a hollow portion formed therein; and  
 a lubrication layer formed thereon;  
 
   at least one first shoe positioned between the swash plate and the first shoe pocket; and    at least one second shoe positioned between the swash plate and the second shoe pocket.    
     
     
         2 . The compressor of  claim 1  wherein the lubrication layer comprises a solid lubricant.  
     
     
         3 . The compressor of  claim 1  wherein the lubrication layer comprises a grease having a viscosity which is sufficient to adhere the grease to the interior surface of the first shoe pocket.  
     
     
         4 . The compressor of  claim 1 , wherein an interior surface of the second shoe pocket is coated with the lubricant.  
     
     
         5 . The compressor of  claim 1 , wherein the first shoe comprises a flat portion and a hemispherical portion, and the hemispherical portion of the first shoe is positioned within the first shoe pocket, such that the hollow portion is sealed by the first shoe.  
     
     
         6 . A piston for use in a compressor comprising: 
 a head portion; and    an engaging portion comprising a first shoe pocket and a second shoe pocket formed therein, wherein an interior surface of the first shoe pocket comprises:    a hollow portion formed therein; and    a lubrication layer formed thereon.    
     
     
         7 . The piston of  claim 6 , wherein the lubrication layer comprises a solid lubricant.  
     
     
         8 . The piston of  claim 6 , wherein the lubrication layer comprises a grease, and the grease has a viscosity sufficient to adhere the grease to the interior surface of the first shoe pocket.  
     
     
         9 . The piston of  claim 6 , wherein an interior surface of the second shoe pocket comprises the lubrication layer, formed thereon.  
     
     
         10 . The piston of  claim 9 , wherein the interior surface of each of the first shoe pocket and the second shoe pocket comprises the hollow portion formed therein.  
     
     
         11 . A piston for use in a compressor comprising: 
 a head portion; and    an engaging portion comprising a first shoe pocket and a second shoe pocket formed therein, wherein an interior surface of the first shoe pocket comprises:    a hollow portion formed therein; and    a lubrication layer formed thereon, wherein an interior surface of the second shoe pocket comprises a penetrating aperture formed there.    
     
     
         12 . The piston of  claim 11 , wherein the lubrication layer comprises a solid lubricant.  
     
     
         13 . The piston of  claim 11 , wherein the lubrication layer comprises a grease, and the grease has a viscosity sufficient to adhere the grease to the interior surface of the first shoe pocket.  
     
     
         14 . The piston of  claim 11 , wherein the interior surface of the second shoe pocket comprises the lubrication layer formed thereon.  
     
     
         15 . A method for manufacturing a piston comprising a head portion and an engaging portion, the method comprising the steps of: 
 forming a first shoe pocket and a second shoe pocket within the engaging portion    forming a hollow portion within an interior surface of the first shoe pocket; and    coating the interior surface of the first shoe pocket with a lubricant.    
     
     
         16 . The method of  claim 15 , further comprising the step of forming the hollow portion within an interior surface of the second shoe pocket.  
     
     
         17 . The method of  claim 15 , further comprising the step of forming a penetrating aperture within an interior surface of the second shoe pocket.  
     
     
         18 . The method of  claim 15 , wherein the hollow portion is formed by forging.  
     
     
         19 . The method of  claim 15 , wherein the hollow portion is formed by cutting.  
     
     
         20 . The method of  claim 17 , wherein each of the hollow portion and the penetrating aperture are formed by drilling.  
     
     
         21 . The method of  claim 15 , wherein the lubricant is selected from the group consisting of a solid lubricant and a liquid lubricant.