Scroll fluid machine

Abstract

A scroll fluid machine comprises a driving shaft having an eccentric axial portion at one end; a fixed scroll having a fixed wrap; and an orbiting scroll having an orbiting wrap and rotatably mounted to the eccentric axial portion of the driving shaft. A gas introduced through an inlet on the outer circumference of the fixed scroll is compressed by a compression chamber between the fixed and orbiting wraps towards the center and discharged through an outlet close to the center. Between the eccentric axial portion and the innermost winding portion of the fixed wrap, an adiabatic expansion chamber is formed thereby cooling the compressed gas right before discharging.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the invention will become more apparent from the following description with respect to an embodiment as shown in accompanying drawings wherein:

FIG. 1 is a vertical sectional view showing one embodiment of a scroll fluid machine according to the present invention;

FIG. 2 is a vertical sectional view taken along the line II-II in FIG. 1;

FIG. 3 is a front view of the inside of a fixed scroll; and

FIG. 4 is an enlarged front view of the main part.

Claims

1. A scroll fluid machine comprising: a driving shaft having an eccentric axial portion at one end;a fixed scroll having a fixed wrap; andan orbiting scroll having an orbiting wrap and rotatably mounted around the eccentric axial portion of the driving shaft to form a compression chamber between the fixed and orbiting wraps, said orbiting scroll being revolved by the driving shaft to reduce a volume of the compression chamber towards a center of the orbiting scroll thereby compressing a gas sucked from an outer circumference of the fixed scroll to discharge it through an outlet close to the center, an adiabatic expansion chamber being formed between an innermost winding portion of the fixed wrap and the eccentric axial portion of the driving shaft.

2. A scroll fluid machine of claim 1 wherein the adiabatic expansion chamber is greater in volume than an innermost compression chamber.

3. A scroll fluid machine of claim 2 wherein a projection is formed on an inner circumferential surface of an innermost winding portion of the fixed wrap, an inner end of the orbiting wrap coming in sliding contact with the projection thereby preventing compressed gas from flowing back to the compression chamber.