Displacement compressor with reduced compressor noise

• US 5,056,995 A
• Filed: 02/23/1990
• Issued: 10/15/1991
• Est. Priority Date: 02/28/1989
• Status: Expired due to Fees

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.)
• Inventors: Yoshidomi, Hideaki, Tamura, Shigehiro, Takeda, Toshio
• Primary Examiner(s): Vrablik, John J.
• Application Number:
  US07/483,668
• Time in Patent Office: 599 Days
• Field of Search: 418/201.1, 418/203, 418/205, 418/206
• US Class Current: 418/201.1
• CPC Class Codes: F04C 18/16 with helical teeth, e.g. chevron-shaped, screw type for non-parallel axes of movement F04C18/48
• CPC Class Codes: F04C 29/12 Arrangements for admission or discharge of the working fluid, e.g. constructional features of the inlet or outlet

Abstract

A displacement compressor has a housing defining a chamber and having an inlet and an outlet for the chamber. A pair of meshing helical rotors are rotatably supported about parallel axes in the chamber, so that a compressible fluid may be pumped from the inlet to the outlet. A recess in the wall of the housing is positioned in the chamber and around the outlet and has a substantially trapezoidal shape, in plan. The non-parallel edges of the substantially trapezoidal shape are angled with respect to the axial direction of the rotors, preferably by an angle which is substantially equal to the twist angle of the rotors. Noise producing pressure pulsations at the outlet are thereby reduced.

Claims

1. A displacement compressor comprising:

a housing defining a chamber therein and having an inlet and an outlet for the chamber;

a pair of meshing helical rotors rotatably supported about parallel axes in said chamber, whereby a compressible fluid may be pumped from the inlet to the outlet; and

a recess in the wall of said housing, said recess being positioned in the chamber and around the outlet, wherein said recess has a substantially trapezoidal shape, in plan, with non-parallel edges thereof being angled with respect to the axial direction of said rotors,

whereby noise producing pressure pulsations at the outlet are reduced,

wherein each of said non-parallel edges forms an angle with respect to the axial direction of said rotors, said angle being substantially equal to a twist angle of said rotors, and

wherein each of said non-parallel edges of said substantially trapezoidal shape is comprised of a plurality of stepped portions which together approximate a straight line having said angle.