Hermetic compressor

Abstract

Relating to oil feed to a piston portion in a dual support bearing of a hermetic compressor, and a structure for improving efficiency and reliability and accomplishing reduction of noise is disclosed. In this structure, since an auxiliary bearing 119 is provided with an oil feed passage 129 for conducting lubricating oil 108 discharged from an upper end of an oil feed mechanism 114, to a sliding surface of a piston 120, the lubricating oil 108 is fed to the piston 120 and a piston pin 122 from the oil feed passage 129 to make the sealing performance excellent, so that the amount of leakage of refrigerant gas from a compression chamber 117 is reduced to improve the freezing capability or efficiency. Further, lubrication of sliding portions of the piston 120 and the piston pin 122 becomes excellent so that noise caused by sliding is reduced and the reliability is improved.

1 . A hermetic compressor having a sealed housing storing therein lubricating oil and receiving therein a motor element and a compression element driven by said motor element, said compression element comprising a shaft having an eccentric shaft portion, and an auxiliary shaft portion and a main shaft portion coaxially provided on upper and lower sides of said eccentric shaft portion so as to sandwich it therebetween, a cylinder block provided with a compression chamber of a substantially cylindrical shape, a main bearing fixed to or formed integral with said cylinder block so as to be substantially perpendicular to an axis of said compression chamber and supporting an upper half portion of said main shaft portion of said shaft, an auxiliary bearing fixed to or formed integral with said cylinder block and supporting said auxiliary shaft portion, a piston that performs reciprocating motion in said compression chamber, and connecting means for coupling said piston and said eccentric shaft together, wherein said shaft is provided with an oil feed mechanism having a lower end communicating with said lubricating oil and an upper end penetratingly open to an upper end portion of said auxiliary shaft portion, and said auxiliary bearing is provided with an oil fence for receiving the lubricating oil spouting out from the upper end portion of said oil feed mechanism and an oil feed passage for conducting the lubricating oil to a sliding surface of said piston.  
     
     
         2 . A hermetic compressor according to  claim 1 , wherein an oil pool for storing said lubricating oil is concavely formed in said oil feed passage on an upper surface of said auxiliary bearing.  
     
     
         3 . A hermetic compressor according to  claim 1 , wherein an oil dispersion hole communicating with said oil feed mechanism is formed in a substantially horizontal direction at a portion of said auxiliary shaft portion above an upper surface of said auxiliary bearing.  
     
     
         4 . A hermetic compressor according to  claim 1 , wherein said oil fence is made to project upward and is provided on an upper surface of said auxiliary bearing in the vicinity of said oil feed passage.  
     
     
         5 . A hermetic compressor according to  claim 1 , wherein an opening portion is provided, said opening portion communicating with said oil feed passage provided on an upper surface of said auxiliary bearing and being open above an oil feed passage provided at a portion of said cylinder block above said compression chamber.  
     
     
         6 . A hermetic compressor according to  claim 5 , wherein an oil guide projecting downward is provided in the vicinity of the opening portion on the side of a lower end surface of said auxiliary bearing.  
     
     
         7 . A hermetic compressor according to  claim 5 , wherein a cylindrical piston pin fixed to said piston and coupling a connecting rod being connecting means and said piston together is provided, and the opening portion is located right above said piston pin in the vicinity of a bottom dead center of said piston and is larger than a horizontal section of said piston pin.  
     
     
         8 . A hermetic compressor according to  claim 1 , wherein a cylinder communicating hole having one end communicating with and open to an upper portion in the compression chamber of said cylinder block is provided in said oil feed passage.  
     
     
         9 . A hermetic compressor according to  claim 1 , wherein a substantially annular oil feed groove communicating with said oil feed passage in the vicinity of a bottom dead center of said piston is concavely formed on an outer periphery of said piston.  
     
     
         10 . A hermetic compressor according to  claim 1 , wherein an oil bath communicating with sliding surfaces between said auxiliary shaft portion and said auxiliary bearing is formed around said auxiliary shaft portion.  
     
     
         11 . A hermetic compressor according to  claim 10 , wherein an oil feed hole is formed on said auxiliary shaft portion, said oil feed hole establishing communication between said oil bath and said oil feed mechanism and having a bottom surface located above a bottom surface of said oil bath.  
     
     
         12 . (canceled)  
     
     
         13 . A hermetic compressor according to  claim 1 , wherein an oil fence projecting upward is provided on a surface of said cylinder block above the compression chamber, and said oil feed passage is formed in the surface of said cylinder block above said compression chamber.  
     
     
         14 . A hermetic compressor according to  claim 1 , which is inverter-driven at a plurality of operating frequencies including at least an operating frequency lower than a power supply frequency.  
     
     
         15 . A hermetic compressor according to  claim 14 , wherein said operating frequency lower than said power supply frequency includes at least an operating frequency lower than 30 Hz.  
     
     
         16 . A hermetic compressor having a sealed housing storing therein lubricating oil and receiving therein a motor element and a compression element driven by said motor element, said compression element comprising a shaft having an eccentric shaft portion, and an auxiliary shaft portion and a main shaft portion coaxially provided on upper and lower sides of said eccentric shaft portion so as to sandwich it therebetween, a cylinder block provided with a compression chamber of a substantially cylindrical shape, a main bearing fixed to or formed integral with said cylinder block so as to be substantially perpendicular to an axis of said compression chamber and supporting an upper half portion of said main shaft portion of said shaft, an auxiliary bearing fixed to or formed integral with said cylinder block and supporting said auxiliary shaft portion, a piston that performs reciprocating motion in said compression chamber, and connecting means for coupling said piston and said eccentric shaft together, wherein said shaft is provided with an oil feed mechanism having a lower end communicating with said lubricating oil and an upper end penetratingly open to an upper end portion of said auxiliary shaft portion, and said cylinder block is provided with an oil fence for receiving the lubricating oil spouting out from the upper end portion of said oil feed mechanism and an oil feed passage for conducting the lubricating oil to a sliding surface of said piston.  
     
     
         17 . A hermetic compressor according to  claim 16 , wherein an oil dispersion hole communicating with said oil feed mechanism is formed in a substantially horizontal direction at a portion of said auxiliary shaft portion above an upper surface of said auxiliary bearing.