Joint structure for refrigerant discharge tubes used in hermetic compressors

Abstract

A joint structure for a refrigerant discharge tube of a hermetic reciprocal compressor having a connecting member fit around the refrigerant discharge tube, the connecting member having a shape corresponding to a connecting hole in a cylinder block, thereby allowing the connecting member to be press-caulked. The refrigerant discharge tube is directly connected to the cylinder block. The connecting hole is multi-layered and may be formed into at least two steps. The connecting member is pre-assembled in the connecting hole by transition-fitting. Accordingly, as the connecting member is press-fit in the connecting hole by a caulking-jig, the connecting member is expanded, and the connecting member is more securely fit in the connecting hole. Further, a thread portion having a pitch in a range of 2 to 5 threads is formed on an inner circumference of the connecting hole. Accordingly, the expanded connecting member penetrates into the thread portion, strengthening the connection between the connecting member and the connecting hole. Since the refrigerant discharge tube is directly connected to the cylinder block, structure is simplified, while the number of assembling steps is reduced. As a result, productivity increases and the manufacturing costs decrease. Further, since the connecting member is fit in the connecting hole by the press-caulking instead of the brazing, higher durability is guaranteed and thus, the breakage of the refrigerant discharge tube is prevented.

What is claimed is:  
     
         1 . A joint structure for a refrigerant discharge tube of a hermetic reciprocal compressor, the refrigerant discharge tube being formed on a cylinder block of the hermetic reciprocal compressor and serving as a passageway for a refrigerant being discharged, 
 the joint structure comprising: 
 a connecting hole formed in the cylinder block in fluid communication with a refrigerant path hole formed inside of the cylinder block; and  
 a connecting member having a shape corresponding to the connecting hole providing for insertion into the connecting hole, whereby  
 the connecting member is directly connected with the cylinder block by press-caulking of the connecting member in the connecting hole.  
   
     
     
         2 . The joint structure of  claim 1 , wherein the connecting hole is formed as a multi-layer structure including two or more layers, and the connecting member is pre-assembled in the connecting hole by transition-fitting, whereby the connecting member is completely press-fit in the connecting hole by expansion therein under the pressure of a caulking jig.  
     
     
         3 . The joint structure of  claim 2 , wherein the connecting hole comprises a thread portion having a pitch in a range of 2 through 5 threads, whereby the connecting member is further secured as the connecting member penetrates into the thread portion by being expanded under the pressure of the caulking jig.  
     
     
         4 . The joint structure of  claim 2 , wherein the connecting member is comprised of a soft iron metal.  
     
     
         5 . The joint structure of  claim 2 , wherein the connecting member is comprised of a soft non-iron metal.