Scroll fluid machine

Abstract

An object is to ensure reliable engagement of a pin and an engagement hole (ring) serving as a rotation prevention mechanism in a scroll fluid machine in which a turn radius of an orbiting scroll is constant. A scroll-type compressor (10) according to the present invention is provided with: a fixed scroll (24); an orbiting scroll (22) that revolves with respect to the fixed scroll (24); a main shaft (14) that includes an input shaft (14a) to which a driving force is transmitted, and an eccentric shaft (14c) that is offset by a predetermined amount with respect to the input shaft (14a) and that transmits the driving force to the orbiting scroll (22); and a pin-and-ring mechanism (27) that is provided between the orbiting scroll (22) and a housing (11) and that prevents rotation of the orbiting scroll (22). When a turn radius of the eccentric shaft (14c) of the main shaft (14) is ρs and a turn radius of a pin (27a), which is determined by the pin (27a) and ring (27b), is ρpin, the pin-and-ring mechanism (27) satisfies ρs<ρpin.

1 . A scroll fluid machine comprising:
 a housing;   a fixed scroll;   an orbiting scroll configured to revolve with respect to the fixed scroll and assembled to define a compression space that compresses fluid between the orbiting scroll and the fixed scroll;   a main shaft including an input shaft to which a driving force is input, and an eccentric shaft offset by a predetermined amount with respect to the input shaft and that transmits the driving force to the orbiting scroll; and   a rotation prevention mechanism for the orbiting scroll provided between the orbiting scroll and the housing, wherein   the housing is configured to house the fixed scroll, the orbiting scroll, the main shaft, and the rotation prevention mechanism,   the rotation prevention mechanism is configured such that a plurality of pins engage with a plurality of engagement holes into which each of the plurality of pins is inserted, and   when a turn radius of the eccentric shaft of the main shaft is ρs and a turn radius of the pin determined by the pin and the engagement hole, is ρpin, ρs<ρpin is satisfied.   
     
     
         2 . The scroll fluid machine according to  claim 1 , wherein
 one of the pin and the engagement hole is displaced in a direction that causes torsion of the orbiting scroll with respect to the fixed scroll to be reduced.   
     
     
         3 . The scroll fluid machine according to  claim 1 , wherein
 of a wrap surface on an outer side and a wrap surface on an inner side of at least one of the fixed scroll and the orbiting scroll,   the wrap surface whose gap is widened with respect to a theoretical curve is thickened such that the gap is narrowed, and the wrap surface whose gap is narrowed with respect to the theoretical curve is thinned such that the gap is widened.   
     
     
         4 . The scroll fluid machine according to  claim 1 , wherein
 when a theoretical turn radius determined by an engagement between the wrap surface of the fixed scroll and the wrap surface of the orbiting scroll is ρth,   ρs<ρpin and ρs<ρth are satisfied.   
     
     
         5 . The scroll fluid machine according to  claim 1 , wherein
 when a theoretical turn radius determined by an engagement between the wrap surface of the fixed scroll and the wrap surface of the orbiting scroll is ρth,   ρs<ρpin≤ρth is satisfied.   
     
     
         6 . The scroll fluid machine according to  claim 1 , wherein
 when a theoretical turn radius determined by an engagement between the wrap surface of the fixed scroll and the wrap surface of the orbiting scroll is ρth,   ρs<ρth<ρpin is satisfied.   
     
     
         7 . The scroll fluid machine according to  claim 1 , wherein
 the theoretical turn radius ρth of the orbiting scroll is constant.   
     
     
         8 . The scroll fluid machine according to  claim 1 , wherein
 of a wrap surface on an outer side and a wrap surface on an inner side of the fixed scroll, the wrap surface whose gap is widened with respect to a theoretical curve is thickened such that the gap is narrowed, and the wrap surface whose gap is narrowed with respect to the theoretical curve is thinned such that the gap is widened.   
     
     
         9 . The scroll fluid machine according to  claim 1 , wherein
 of a wrap surface on an outer side and a wrap surface on an inner side of the orbiting scroll, the wrap surface whose gap is widened with respect to a theoretical curve is thickened such that the gap is narrowed, and the wrap surface whose gap is narrowed with respect to the theoretical curve is thinned such that the gap is widened.   
     
     
         10 . The scroll fluid machine according to  claim 7 , wherein
 of a wrap surface on an outer side and a wrap surface on an inner side of the fixed scroll, the wrap surface whose gap is widened with respect to a theoretical curve is thickened such that the gap is narrowed, and the wrap surface whose gap is narrowed with respect to the theoretical curve is thinned such that the gap is widened.   
     
     
         11 . The scroll fluid machine according to  claim 7 , wherein
 of a wrap surface on an outer side and a wrap surface on an inner side of the orbiting scroll, the wrap surface whose gap is widened with respect to a theoretical curve is thickened such that the gap is narrowed, and the wrap surface whose gap is narrowed with respect to the theoretical curve is thinned such that the gap is widened.