Scroll fluid machine

Abstract

The scroll-type compressor comprises a fixed scroll 320 and an orbiting scroll which are engaged with each other, a front housing 220 for accommodating the fixed scroll 320 and the orbiting scroll, and a rear housing 240 joined to the open end of the front housing 220 . The fixed scroll 320 has the base plate 322 fitted into the front housing 220 , and the flange 326 held at a joint surface between the front housing 220 and the rear housing 240 . Additionally, at least one of the flange 326 of the fixed scroll 320 and the front housing 220 forms therein a recessed portion 326 A or 220 E which permits the fixed scroll 320 to be displaced in an axial direction toward the orbiting scroll due to a pressure difference acting on opposite surfaces of the base plate 322 of the fixed scroll 320.

1 . A scroll fluid machine comprising:
 a fixed scroll and an orbiting scroll engaged with each other;   a first housing for accommodating the fixed and orbiting scrolls, and   a second housing joined to an open end of the first housing;   wherein the fixed scroll has a base plate fitted into the first housing, and a flange held at a joint surface between the first and second housings, and   at least one of the flange of the fixed scroll and the first housing has a recessed portion formed therein which permits the fixed scroll to be displaced in an axial direction toward the orbiting scroll due to a pressure difference acting on opposite surfaces of the base plate of the fixed scroll.   
     
     
         2 . The scroll fluid machine according to  claim 1 , wherein the recessed portion formed in the flange of the fixed scroll includes an annular recessed groove facing an inner peripheral end portion of the first housing. 
     
     
         3 . The scroll fluid machine according to  claim 1 , wherein the recessed portion formed in the first housing includes an annular recessed groove or a chamfer positioned in the inner peripheral end portion of the first housing. 
     
     
         4 . The scroll fluid machine according to  claim 1 , wherein a boss, into which a shaft portion of a bolt for fastening the first and second housings is screwed from the second housing side, is formed on an outer peripheral surface of the first housing, and
 at least a part of the tip portion side of the bolt in the boss is formed to be thin.   
     
     
         5 . The scroll fluid machine according to  claim 1 , wherein a shim for adjusting an axial-direction clearance between the fixed and orbiting scrolls is sandwiched between the first housing and the flange of the fixed scroll. 
     
     
         6 . The scroll fluid machine according to  claim 2 , wherein the recessed portion formed in the first housing includes an annular recessed groove or a chamfer positioned in the inner peripheral end portion of the first housing. 
     
     
         7 . The scroll fluid machine according to  claim 2 , wherein a boss, into which a shaft portion of a bolt for fastening the first and second housings is screwed from the second housing side, is formed on an outer peripheral surface of the first housing, and
 at least a part of the tip portion side of the bolt in the boss is formed to be thin.   
     
     
         8 . The scroll fluid machine according to  claim 3 , wherein a boss, into which a shaft portion of a bolt for fastening the first and second housings is screwed from the second housing side, is formed on an outer peripheral surface of the first housing, and
 at least a part of the tip portion side of the bolt in the boss is formed to be thin.   
     
     
         9 . The scroll fluid machine according to  claim 2 , wherein a shim for adjusting an axial-direction clearance between the fixed and orbiting scrolls is sandwiched between the first housing and the flange of the fixed scroll. 
     
     
         10 . The scroll fluid machine according to  claim 3 , wherein a shim for adjusting an axial-direction clearance between the fixed and orbiting scrolls is sandwiched between the first housing and the flange of the fixed scroll. 
     
     
         11 . The scroll fluid machine according to  claim 4 , wherein a shim for adjusting an axial-direction clearance between the fixed and orbiting scrolls is sandwiched between the first housing and the flange of the fixed scroll.