Piston ring manufacturing method
AssigneeSanden Corporation
InventorKatsumasa Azami
Life of this patent
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Abstract
A method for manufacturing a piston ring for use in a refrigerant compressor is disclosed. The method includes the steps of disposing the piston ring in an annular groove which is formed on one end surface of a fixed holder; and pressuring the piston ring in the groove by a lower end surface of a press until the lower end surface of the press contacts the upper end surface of the fixed holder. At least one projection formed on either the fixed holder or the press contacts the piston ring. A plurality of grooves are thereby formed on one end surface of the piston ring as the pressing operation progresses.
Claims7
A method for manufacturing a piston ring with at least one groove transverse to said piston ring to permit passage of blow-by gas when said piston ring is installed on a piston, the method comprising the steps of:
- securing a pre-formed piston ring on a fixed holder, said pre-formed piston ring having a substantially uniform shape with opposing top and bottom surfaces and inner and outer annular side surfaces;
- pressing said pre-formed piston ring while secured on said fixed holder with a press to cause at least one projection extending perpendicular in the axial direction to the surface of said pre-formed piston ring being pressed to deform said pre-formed piston ring to form at least one groove on said pre-formed piston ring without otherwise significantly externally deforming said pre-formed piston ring, wherein after said pressing step said at least one groove is formed on one of said top and bottom surfaces;
- removing said pre-formed piston ring from said fixed holder;
- and
- twisting said pre-formed piston ring so that said opposing top and bottom surfaces become inner and outer annular side surfaces and said at least one groove faces outwardly of said preformed piston ring.
Dependencies are inferred from the claim text.