Seal in a scroll fluid machine

Abstract

In a scroll fluid machine, an orbiting scroll comprises an orbiting end plate having an orbiting wrap and a fixed scroll comprises a fixed end plate having a fixed wrap. An engagement groove is formed at the tip ends of the orbiting wrap and fixed wrap, and/or the fixed or orbiting end plate. A seal is fitted in the engagement groove in sliding contact with a counter member. The seal comprises a sealing material and a backup material between the sealing material and the bottom of the engagement groove. The backup material has a plurality of projections which elastically stretch to press the inner circumferential surface of the engagement groove when the seal is pressed.

1 . A seal in a scroll fluid machine comprising an orbiting scroll and a fixed scroll, said orbiting scroll comprising an orbiting end plate having an orbiting wrap, said fixed scroll comprising a fixed end plate having a fixed wrap, said seal being fitted in an engagement groove of an outer circumference of a fixed end plate or an orbiting end plate, and/or a tip end of the orbiting wrap and a tip end of the fixed wrap, said seal comprising: 
 a backup material made of elastic material and having a plurality of projections which elastically stretch, when said seal is pressed, to press on an inner circumferential surface to enable the seal to be positioned in the engagement groove exactly and to enable gas-tightness to be kept in the engagement groove; and    a sealing material putting on an upper surface of the backup material and being in sliding contact with a counter member.    
   
   
       2 . A seal according to  claim 1  wherein said plurality of projections comprise a plurality of protuberances extending sideward from each side of a middle of the backup material.  
   
   
       3 . A seal according to  claim 1  wherein said plurality of projections comprise a plurality of protuberances extending sideward from each side of an upper end of the backup material.  
   
   
       4 . A seal according to  claim 1  wherein said plurality of projections comprise a plurality of arms formed obliquely from an upper end of the backup material to support the sealing material.  
   
   
       5 . A seal according to  claim 4  wherein said plurality of arms gradually become thinner outwards.  
   
   
       6 . A seal according to  claim 4  wherein a head is provided in a middle of an upper surface of the backup material to support the sealing material.  
   
   
       7 . A seal according to  claim 1  wherein a plurality of projections comprises a plurality of protuberances extending sideward from each side of a lower end of the backup material.  
   
   
       8 . A seal according to  claim 1  wherein said plurality of projections comprise a plurality of legs extending from a lower end of the backup material.  
   
   
       9 . A seal according to  claim 8  wherein said plurality of legs gradually become thinner outward.  
   
   
       10 . A seal according to  claim 8  wherein a downward protrusion is formed from a middle of the lower end of backup material.  
   
   
       11 . A seal according to  claim 1  wherein said plurality of projections comprise a plurality of protuberances extending sideward from each side of upper and lower ends of the backup material.  
   
   
       12 . A seal according to  claim 1  wherein said plurality of projections comprise a plurality of upward-inclined arms to support the sealing material and a plurality of downward-inclined legs supported by a bottom of the engagement groove.