Linear compressor

Abstract

A linear compressor is provided that may include a shell provided with a refrigerant inlet; a cylinder provided inside of the shell to form a compression space; a piston that reciprocates inside of the cylinder to compress a refrigerant in the compression space; and a motor assembly that provides a drive force to the piston and provided with a permanent magnet. The piston may include a piston body having a cylindrical outer circumferential surface and a surface-treated area, which may be processed with a material having a predetermined hardness value, and a valve support provided at an end of the piston body and having a suctioning hole be in communication with the compression space. The valve support may form a first non-surface-treated area, which is not surface-treated.

What is claimed is: 
     
         1 . A linear compressor, comprising:
 a shell provided with a refrigerant inlet;   a cylinder provided inside of the shell to form a compression space;   a piston that reciprocates inside the cylinder to compress a refrigerant in the compression space; and   a motor assembly that provides a drive force to the piston and provided with a permanent magnet, wherein the piston comprises:
 a piston body having a cylindrical outer circumferential surface including a first surface-treated area comprising a material having a predetermined hardness value; and 
 a valve support provided at a first end of the piston body and having a suction hole in communication with the compression space, the valve support having a first non-surface-treated area. 
   
     
     
         2 . The linear compressor of  claim 1 , wherein the valve support includes a surface that faces the compression space, and the first non-surface-treated area is formed on the surface. 
     
     
         3 . The linear compressor of  claim 1 , wherein the first non-surface-treated area comprises a nonmagnetic material that delivers heat, during the compression to the piston body. 
     
     
         4 . The linear compressor of  claim 1 , further comprising a flange coupled to a second end of the piston body that extends in a radial direction of the piston body, wherein the cylindrical outer circumferential surface comprises:
 a first outer circumferential surface area that forms the first surface-treated area; and   a second outer circumferential surface area that forms a second non-surface-treated area.   
     
     
         5 . The linear compressor of  claim 4 , wherein the first outer circumferential surface area is an outer circumferential surface area that extends from the first end of the piston body toward the flange. 
     
     
         6 . The linear compressor of  claim 4 , wherein the second outer circumferential surface area is an outer circumferential surface area that extends from the second end of the piston body to which the flange is coupled, toward the valve support. 
     
     
         7 . The linear compressor of  claim 1 , wherein the first non-surface-treated portion of the valve support is spaced from a second non-surface-treated area. 
     
     
         8 . The linear compressor of  claim 7 , wherein the first non-surface-treated area is formed at a first end of the piston body, and the second non-surface-treated area is formed at a second end of the piston body. 
     
     
         9 . The linear compressor of  claim 7 , wherein the second non-surface-treated area comprises a nonmagnetic material that delivers heat of the cylinder to the piston body. 
     
     
         10 . The linear compressor of  claim 1 , further comprising a suction valve coupled to the valve support to selectively open the suction hole. 
     
     
         11 . The linear compressor of  claim 1 , wherein the piston and the cylinder are made of a nonmagnetic material. 
     
     
         12 . The linear compressor of  claim 11 , wherein the piston and the cylinder are made of aluminum or an aluminum alloy. 
     
     
         13 . A linear compressor, comprising:
 a shell provided with a refrigerant inlet;   a cylinder provided inside of the shell to form a compression space;   a piston that reciprocates inside the cylinder to compress a refrigerant in the compression space; and   a motor assembly that provides a drive force to the piston and provided with a permanent magnet, wherein the piston comprises:
 a piston body having a cylindrical outer circumferential surface including a first surface-treated area, and a first non-surface-treated area; 
 a valve support provided at a first end of the piston body and having a suction hole in communication with the compression space; 
 a suction valve that selectively opens the suction hole; and 
 a second non-surface-treated area comprising a non-magnetic material on an outer surface of the valve support. 
   
     
     
         14 . The linear compressor of  claim 13 , wherein the first non-surface-treated area comprises a nonmagnetic material that delivers heat, during the compression to the piston body. 
     
     
         15 . The linear compressor of  claim 13 , further comprising a flange coupled to a second end of the piston body that extends in a radial direction of the piston body, wherein the cylindrical outer circumferential surface comprises:
 a first outer circumferential surface area that forms the first surface-treated area; and   a second outer circumferential surface area that forms a second non-surface-treated area.   
     
     
         16 . The linear compressor of  claim 13 , wherein the piston and the cylinder are made of a nonmagnetic material. 
     
     
         17 . The linear compressor of  claim 16 , wherein the piston and the cylinder are made of aluminum or an aluminum alloy. 
     
     
         18 . A linear compressor, comprising:
 a shell provided with a refrigerant inlet;   a cylinder provided inside of the shell to form a compression space;   a piston that reciprocates inside the cylinder to compress a refrigerant in the compression space; and   a motor assembly that provides a drive force to the piston and provided with a permanent magnet, wherein the piston comprises:
 a piston body having a cylindrical outer circumferential surface including a first surface area comprising a material having a predetermined hardness value; and 
 a valve support provided at a first end of the piston body and having a suction hole in communication with the compression space, the valve support having a surface that faces the compression space, at least a portion of the surface comprising a nonmagnetic material that delivers heat, during the compression to the piston body. 
   
     
     
         19 . The linear compressor of  claim 18 , wherein the cylindrical outer circumferential surface comprises:
 a first outer circumferential surface area that forms the first surface area; and   a second outer circumferential surface area that forms a second surface area having a different hardness value from the predetermined hardness value.   
     
     
         20 . The linear compressor of  claim 19 , wherein the first outer circumferential surface area is surface-treated to provide the predetermined hardness and the second outer circumferential surface area is not surface treated. 
     
     
         21 . The linear compressor of  claim 18 , wherein the piston and the cylinder are made of a nonmagnetic material. 
     
     
         22 . The linear compressor of  claim 21 , wherein the piston and the cylinder are made of aluminum or an aluminum alloy.