Reciprocating Fluid Machine

Abstract

A reciprocating fluid machine includes a cylinder block ( 18 ) arranged inside a casing shell ( 16 ) and having cylinder bores ( 38 ), a cylinder head ( 54 ) fastened to the casing shell ( 16 ), a valve plate ( 50 ) interposed between the cylinder block ( 18 ) and the cylinder head ( 54 ) each with a gasket ( 46, 48, 52 ) therebetween, and a fastening device for fastening the valve plate ( 50 ) to the cylinder block ( 18 ). The fastening device includes outer tapped holes ( 42 ) formed in the cylinder block ( 18 ), and outer fastening bolts ( 68 ) extending from the cylinder head side through the valve plate ( 50 ) and the gaskets ( 46, 48, 52 ) and screwed into the respective outer tapped holes ( 42 ). The outer fastening bolts ( 68 ) have axes located outward of a bore distribution circle on which the axes of the cylinder bores ( 38 ) are located, as viewed in the radial direction of the cylinder block ( 54 ), and have bolt heads ( 69 ) located inside the cylinder head ( 54 ).

1 . A reciprocating fluid machine comprising:
 a housing;   a cylinder block having at least part thereof contained in the housing and including a plurality of cylinder bores therein, the cylinder bores having axes located on a bore distribution circle concentric with an axis of the cylinder block;   a cylinder head fastened to the housing and including a suction chamber and a discharge chamber for a working fluid, the suction and discharge chambers opening toward the cylinder block;   a compression unit including a valve mechanism having pistons received in the respective cylinder bores and capable of reciprocating motion therein and a valve plate interposed between the cylinder block and the cylinder head each with a gasket therebetween, the reciprocating motion of the pistons and operation of the valve mechanism causing the compression unit to successively carry out suction of the working fluid from the suction chamber into the cylinder bores, compression of the sucked working fluid in the cylinder bores, and discharge of the compressed working fluid from the cylinder bores to the discharge chamber; and   a fastening device for fastening the valve plate to the cylinder block,   the fastening device including
 a plurality of outer tapped holes formed in the cylinder block and extending parallel with the cylinder bores, the outer tapped holes having axes located outward of the bore distribution circle as viewed in a radial direction of the cylinder block, and 
 a plurality of outer fastening bolts extending from a side near the cylinder head through the valve plate and the gaskets and screwed into the respective outer tapped holes, the outer fastening bolts having bolt heads located inside the cylinder head. 
   
   
   
       2 . The reciprocating fluid machine according to  claim 1 , wherein the bolt heads of the outer fastening bolts are located in the suction chamber, and the suction chamber has an annular form surrounding the discharge chamber. 
   
   
       3 . The reciprocating fluid machine according to  claim 1 , wherein the fastening device further includes:
 a center tapped hole formed in the cylinder block coaxially with the cylinder block; and   a center fastening bolt extending from the side near the cylinder head through the valve plate and the gaskets and screwed into the center tapped hole, the center fastening bolt having a bolt head located inside the cylinder head.   
   
   
       4 . The reciprocating fluid machine according to  claim 3 , wherein the bolt head of the center fastening bolt is located in the discharge chamber, and the discharge chamber is located at center of the cylinder head. 
   
   
       5 . The reciprocating fluid machine according to  claim 4 , wherein the valve mechanism includes discharge valves for controlling discharge of the compressed working fluid, and
 the center fastening bolt serves also as a fixing bolt for fixing the discharge valves to the valve plate.   
   
   
       6 . The reciprocating fluid machine according to  claim 1 , wherein the fastening device further includes:
 a plurality of inner tapped holes formed in the cylinder block and having axes located inward of the bore distribution circle as viewed in the radial direction of the cylinder block, and   a plurality of inner fastening bolts extending from the side near the cylinder head through the valve plate and the gaskets and screwed into the respective inner tapped holes, the inner fastening bolts having bolt heads located inside the cylinder head.   
   
   
       7 . The reciprocating fluid machine according to  claim 6 , wherein the bolt heads of the inner fastening bolts are located in the discharge chamber, and the discharge chamber is located at center of the cylinder head. 
   
   
       8 . The reciprocating fluid machine according to  claim 1 , wherein the outer fastening bolts each comprise a stud bolt buried in the cylinder block, and
 the fastening device further includes nuts screwed onto the respective stud bolts and pressing the valve plate against the cylinder block.   
   
   
       9 . The reciprocating fluid machine according to  claim 1 , wherein the fluid machine is a compressor used for compressing CO 2  refrigerant flowing through a refrigeration circuit.