Reciprocating compressor

Abstract

A reciprocating compressor is provided. The compressor includes a casing, a frame fixed to an inner circumferential surface of the casing, an oil storage portion formed in the frame, and an oil pocket formed at an outer circumferential surface of a piston and in communication with the oil storage portion. The piston reciprocates within a cylinder and pumps oil based on a change in volume of the oil in the oil pocket. Since an additional space to contain oil in the casing and an additional oil pumping device are not required, size of the compressor is reduced and structure is simplified. Furthermore, since oil is automatically pumped when the piston reciprocates, reliability of the compressor is enhanced.

1 . A compressor, comprising: 
 a frame configured to support a reciprocating motor having a stator and a mover;    a cylinder inserted into and coupled to the frame, wherein the cylinder and the frame each have at least one passage formed in a respective radial direction thereof which are configured to allow fluid to flow therethrough; and    a piston configured to be slidably inserted into the cylinder and to be coupled to the mover, wherein the piston comprises a pocket formed on an outer circumferential surface thereof, wherein the pocket is connected to the at least one passage formed in the cylinder so as to generate a pressure difference therebetween based on a volume of fluid in the pocket.    
   
   
       2 . The reciprocating compressor of  claim 1 , wherein the compressor comprises a horizontal or a vertical reciprocating compressor.  
   
   
       3 . The reciprocating compressor of  claim 1 , wherein a storage portion configured to receive a predetermined amount of fluid therein as formed as a recess in the frame, and wherein the at least one passage formed in of the cylinder is in communication with storage portion.  
   
   
       4 . The reciprocating compressor of  claim 3 , wherein the at least one passage formed in the frame provides for fluid communication between the storage portion and the at least one passage formed in the cylinder.  
   
   
       5 . The reciprocating compressor of  claim 1 , wherein an inner circumferential surface of the cylinder is in sliding-contact an outer circumferential surface of the piston which excludes the pocket.  
   
   
       6 . The reciprocating compressor of  claim 1 , wherein a vertical length of the pocket is greater than a diameter of the at least one passage formed in the cylinder, and wherein an upper end of the pocket is positioned higher than the at least one passage formed in the cylinder.  
   
   
       7 . The reciprocating compressor of  claim 1 , wherein the at least one passage formed in the cylinder is positioned within a reciprocation range of the pocket.  
   
   
       8 . A reciprocating compressor, comprising: 
 a frame configured to support a reciprocating motor having a mover and a stator;    a cylinder inserted into and coupled to the frame, wherein the cylinder has at least one passage formed in a radial direction thereof, and a fixed pocket formed as a recess in an inner circumferential surface thereof which is in communication with the at least one passage formed in the cylinder; and    a piston coupled to the mover and configured to be slidably inserted into the cylinder, wherein the piston comprises a movable pocket formed as a recess in an outer circumferential surface thereof, wherein the moveable pocket and the fixed pocket are configured to generate a pressure difference due to a corresponding change volume.    
   
   
       9 . The reciprocating compressor of  claim 8 , further comprising a fluid storage portion formed as a recess in the frame, wherein the at least one passage formed in the cylinder is positioned proximate the storage portion.  
   
   
       10 . The reciprocating compressor of  claim 9 , further comprising a passage formed in the frame which extends between the storage portion and the at least one passage formed in the cylinder so as to provide for fluid communication therebetween.  
   
   
       11 . The reciprocating compressor of  claim 8 , wherein an inner circumferential surface of the cylinder which excludes the fixed pocket is in sliding contact with an outer circumferential surface of the piston which excludes the moveable pocket.  
   
   
       12 . The reciprocating compressor of  claim 8 , wherein an outer diameter of the piston is substantially uniform except for a portion thereof which forms the moveable pocket, and wherein an inner diameter the cylinder varies such that an inner circumferential surface of the cylinder which excludes the fixed pocket maintains sliding-contact with an outer circumferential surface of the piston which excludes the moveable pocket.  
   
   
       13 . The reciprocating compressor of  claim 8 , wherein a length of the fixed pocket and a length of the moveable pocket in a vertical direction are each greater than a diameter of the at least one passage formed in the cylinder, and wherein upper ends of the fixed and moveable pockets are positioned higher than the at least one passage formed in the cylinder.  
   
   
       14 . The reciprocating compressor of  claim 8 , wherein the at least one passage formed in the cylinder is positioned within a reciprocation range of the fixed and moveable pockets.  
   
   
       15 . A reciprocating compressor, comprising: 
 a casing:    a frame coupled to an inner circumferential surface of the casing, comprising a fluid storage portion formed as a recess along an outer circumferential surface thereof;    a reciprocating motor having a stator coupled to the frame and a mover configured to reciprocate in a vertical direction;    a cylinder fixed to the frame and having at least one passage in communication with the storage portion of the frame;    a piston coupled to the mover and configured to be slidably inserted into the cylinder; and    a pocket formed at either the cylinder or the piston so as to be in communication with the at least one passage formed in the cylinder, wherein the pocket is configured to generate a pressure difference due to a change in volume of a fluid in the pocket when the piston is reciprocated.    
   
   
       16 . The reciprocating compressor of  claim 15 , wherein the storage portion has a ring shape.  
   
   
       17 . The reciprocating compressor of  claim 15 , wherein the at least one passage formed in the cylinder is positioned within a reciprocation range of the pocket.  
   
   
       18 . The reciprocating compressor of  claim 15 , wherein the pocket is formed in the piston, and wherein an outer diameter of the piston is substantially uniform except for a portion thereof which forms the pocket, and wherein an inner diameter or the cylinder is substantially uniform such that an inner circumferential surface thereof maintains sliding-contact with an outer circumferential surface of the piston which excludes the pocket.  
   
   
       19 . The reciprocating compressor of  claim 15 , wherein the pocket is formed in the piston, and wherein an outer diameter of the piston varies, and wherein an inner diameter of the cylinder varies corresponding to the outer diameter of the piston such that an inner circumferential surface of the cylinder maintains sliding-contact with an outer circumferential surface of the piston which excludes the pocket.  
   
   
       20 . The reciprocating compressor of  claim 15 , wherein a vertical length of the pocket is greater than a diameter of the at least one passage formed in the cylinder, and wherein an upper end of the pocket is positioned higher than an upper end of the at least one passage.