Improvement in a piston for a refrigeration compressor

Abstract

The piston (P) comprises a tubular skirt ( 10 ), and a head (H) affixed in the interior of the skirt ( 10 ), close to an end edge ( 11 ) of the latter and carrying a suction valve ( 20 ). The head (H) comprises a central hub ( 30 ) having an end front face ( 30 a ) and incorporating radial wings ( 31 ) whose end edges ( 31 a ) are affixed to the skirt ( 10 ). The central hub ( 30 ) defines, with the skirt ( 10 ) and the radial wings ( 31 ), respective suction axial passages ( 32 ). The head (H) further comprises a cover ( 40 ) having a contour concentric to the inner contour of the skirt ( 10 ) and having a front face ( 40 a ) and a rear face ( 40 b ) which is affixed to the central hub ( 30 ) by the end front face ( 30 a ) of the latter, the contour of the cover ( 40 ) maintaining, with the inner contour of the skirt ( 10 ), a radial gap which defines a suction annular opening ( 42 ) to be closed by the suction valve ( 20 ).

1 . An improvement in a piston for a refrigeration compressor, said piston comprising a tubular skirt, and a head affixed in the interior of the skirt, close to an end edge of the latter and carrying a suction valve, the improvement being characterized in that the head is formed: by a central hub having a contour reduced in relation to that of the skirt, having an end front face and incorporating, in a single piece, radial wings whose end edges are affixed to the skirt, in the interior of the latter, said central hub defining, between its contour and the skirt and between the radial wings, respective suction axial passages; and by a cover defined by a plate having a contour concentric to the inner contour of the skirt, and having a front face and a rear face which is affixed to the central hub by the end front face of the latter, the contour of the cover maintaining, with the inner contour of the skirt, a radial gap which defines a suction annular opening to be selectively closed by the suction valve. 
     
     
         2 . The improvement, according to  claim 1 , characterized in that the front face of the cover is coplanar to a plane containing said end edge of the skirt. 
     
     
         3 . The improvement, according to  claim 1 , characterized in that the end edge of each radial wing is fitted and affixed in a recess provided in the interior of the skirt in the inner end region of the latter and opened to the end edge thereof. 
     
     
         4 . The improvement, according to  claim 3 , characterized in that the recess occupies a circumferential extension of the inner contour of the skirt, defining a respective step, in relation to said inner contour, axially spaced back in relation to said end edge of the skirt. 
     
     
         5 . The improvement, according to  claim 4 , characterized in that it comprises a continuous single recess occupying the inner circumferential contour of the skirt. 
     
     
         6 . The improvement, according to  claim 1 , characterized in that the end edges of the radial wings incorporate, in a single piece, a peripheral ring circumferential extension which is radially seated and affixed against the skirt, in the interior of the latter. 
     
     
         7 . The improvement, according to  claim 6 , characterized in that the peripheral ring circumferential extension is fitted and affixed in a recess, provided in the interior of the skirt in the region of the end edge of the latter, open to said end edge of the skirt and occupying a respective circumferential extension of the inner contour of the skirt, in order to define an annular step, in relation to said inner contour, axially spaced back in relation to said end edge of the skirt. 
     
     
         8 . The improvement, according to  claim 7 , characterized in that the end edges of the radial wings are joined by a single peripheral ring circumferential extension. 
     
     
         9 . The improvement, according to  claim 7 , characterized in that the peripheral ring circumferential extension presents an axial height equal to that of the radial wings, said peripheral ring circumferential extension being coplanar to the radial wings. 
     
     
         10 . The improvement, according to  claim 1 , characterized in that the radial wings are axially spaced back and away from the rear face of the cover. 
     
     
         11 . The improvement, according to  claim 10 , characterized in that the radial wings are axially spaced back and away from the end front face of the central hub. 
     
     
         12 . The improvement, according to  claim 11 , characterized in that the central hub presents an axial through hole open to the end front face thereof, the cover incorporating, in the rear face thereof, a central axial pin which is fitted and affixed in the axial through hole of the central hub, upon the seating of the rear face of the cover against the end front face of the central hub, to secure the cover to the central hub. 
     
     
         13 . The improvement, according to  claim 11 , characterized in that the central hub is massive and incorporates, in the end front face thereof, a central axial pin, the cover being provided with a central axial hole open to the rear face of the latter and in which is fitted and affixed the central axial pin upon the seating of the rear face of the cover against the end front face of the central hub, to secure the cover to the central hub. 
     
     
         14 . The improvement, according to  claim 10 , characterized in that the radial wings have the same axial extension of the central hub and are coplanar thereto. 
     
     
         15 . The improvement, according to  claim 14 , characterized in that the central hub presents an axial through hole open to the end front face thereof, the cover incorporating, in the rear face thereof, a central axial pin comprising a base portion having a greater contour than that of said axial through hole and a mounting portion, having a smaller contour and which is fitted and affixed in the axial through hole of the central hub, upon the seating of said base portion against the end front face of the central hub, for securing the cover to the central hub. 
     
     
         16 . The improvement, according to  claim 14 , characterized in that the cover is provided with a central axial hole open to the rear face of the latter, the central hub being massive and having an end portion projecting axially beyond the radial wings, to be fitted and affixed in the central axial hole of the cover.