Scroll fluid machine

Abstract

A scroll fluid machine comprises a fixed scroll and an orbiting scroll that engages with the fixed scroll to form a compression chamber between the fixed and orbiting scrolls. Near the outer circumference of the fixed and/or orbiting scroll, an annular dust-seal groove is provided. In the groove, a dust seal fits to prevent a gas from coming into the compression chamber or from leaking out of the compression chamber. In the dust-seal groove, an annular holder or piece is provided to prevent heat from transferring to the dust seal.

1 . A scroll fluid machine comprising:
 a fixed scroll having a fixed end plate; and   an orbiting scroll having an orbiting end plate, a dust-seal groove being formed close to an outer circumference of the fixed and/or orbiting scroll, an annular holder that fits in the dust-seal groove, the annular holder being made of material having thermal conductivity lower than material of said scrolls and having a groove in which a dust seal fits.   
   
   
       2 . A scroll fluid machine of  claim 1  wherein the annular holder is cast together with the scroll when the scroll is cast. 
   
   
       3 . A scroll fluid machine of  claim 1  wherein the annular holder is fixed in the dust-seal groove. 
   
   
       4 . A scroll fluid machine of  claim 1  wherein the annular holder is pressingly fitted in the dust-seal groove. 
   
   
       5 . A scroll fluid machine of  claim 3  wherein the annular holder is fitted in the dust-seal groove owing to difference in thermal expansion rate. 
   
   
       6 . A scroll fluid machine of  claim 1  wherein the fixed and orbiting scrolls are made of Al or Al alloy and the annular holder is made of steel. 
   
   
       7 . A scroll fluid machine of  claim 1  wherein an unevenness is formed axially on an outer circumferential surface of the annular holder. 
   
   
       8 . A scroll fluid machine of  claim 1  wherein an unevenness is formed circumferentially on an outer circumferential surface of the annular holder. 
   
   
       9 . A scroll fluid machine of  claim 1  wherein a groove is radially formed on an outer circumferential surface of the annular holder. 
   
   
       10 . A scroll fluid machine of  claim 1  wherein a hole goes through a bottom wall of the annular holder. 
   
   
       11 . A scroll fluid machine of  claim 1  wherein a side wall of the annular holder becomes thicker towards a bottom. 
   
   
       12 . A scroll fluid machine of  claim 1  wherein a radial projection is provided at a bottom of the annular holder. 
   
   
       13 . A scroll fluid machine comprising:
 a fixed scroll having a fixed end plate; and   an orbiting scroll having an orbiting end plate, a dust-seal groove being formed close to an outer circumference of the fixed and/or orbiting scroll, an annular piece being formed on an inner circumferential surface of the dust-seal groove, the annular piece being made of metal having thermal conductivity lower than material of said scrolls.   
   
   
       14 . A scroll fluid machine of  claim 13  wherein the annular piece is formed by plating. 
   
   
       15 . A scroll fluid machine of  claim 13  wherein the annular piece is formed by thermal spraying. 
   
   
       16 . A scroll fluid machine of  claim 13  wherein the annular piece has unevenness. 
   
   
       17 . A scroll fluid machine of  claim 13  wherein the annular piece becomes thicker gradually towards a bottom of the dust-seal groove.