Scroll compressor with certain pressure ratio between discharge pressure and suction pressure and with certain ratio of diameter of orbiting mirror plate and outer diameter of the annular seal

• US 7,614,859 B2
• Filed: 06/09/2004
• Issued: 11/10/2009
• Est. Priority Date: 06/12/2003
• Status: Expired due to Fees

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Iida, Noboru, Akazawa, Teruyuki, Hiwata, Akira, Futagami, Yoshiyuki, Sawai, Kiyoshi
• Primary Examiner(s): Trieu; Theresa
• Application Number:
  US10/560,037
• Publication Number:
  US 20080038133A1
• Time in Patent Office: 1,980 Days
• Field of Search: 418 551- 57, 418/270, 418/DIG.1
• US Class Current: 418/55.1
• CPC Class Codes: F04C 18/0215 where only one member is moving
• CPC Class Codes: F04C 23/008 Hermetic pumps
• CPC Class Codes: F04C 27/005 Axial sealings for working fluid
• CPC Class Codes: F04C 29/023 Lubricant distribution through a hollow driving shaft F04C29/025 takes precedence

Abstract

A back pressure chamber (12) provided on a back surface of an orbiting scroll (5) is divided into an inner region (12a) and an outer region (12b) by an annular seal (11). A diameter d of the annular seal (11) is set 0.5 times or more of a diameter D of an orbiting mirror plate (5a). With this, plus thrust force can be applied to the orbiting scroll (5) irrespective of magnitude of a discharge pressure Pd applied to the inner region (12a). Therefore, it is possible to push the orbiting scroll (5) against the fixed scroll (4) only by back pressure of discharge pressure. A set pressure Pm of the outer region (12b) is reduced to a value close to a suction pressure Ps, a pressure adjusting mechanism (20) is swiftly opened after a scroll compressor is started. With this, lubricant oil is supplied from the outer region (12b) to the suction space (9) without a time lag.

Claims

1. A scroll compressor wherein a fixed scroll having a fixed scroll wrap on a fixed mirror plate and an orbiting scroll having an orbiting scroll wrap on an orbiting mirror plate are combined with each other to form a plurality of compressed chambers, a back pressure chamber is provided on a surface on the opposite side from said orbiting scroll wrap surface of said orbiting scroll, a suction space is formed in an outer periphery of said fixed scroll, said back pressure chamber is divided by an annular seal into an inner region and an outer region, a lubricant oil in a discharge pressure state is supplied to said inner region of said annular seal, a portion of the lubricant oil is decompressed at a narrowed portion and supplied to said outer region, the lubricant oil in the outer region is supplied to said suction space, pressure in said inner region is set to discharge pressure Pd, pressure in said outer region is set to a predetermined pressure Pm between a suction pressure Ps and a discharge pressure Pd, thrust force is applied to a back surface of said orbiting scroll, thereby bringing said orbiting scroll into contact with said fixed scroll, rotation of said orbiting scroll is restrained by a rotation-restraint member, said orbiting scroll is allowed to orbit, thereby moving said compressed chamber toward a center of scroll while reducing its volume, refrigerant gas is sucked from the suction space into said compressed chamber and compressed,

a pressure ratio (Pd/Ps) between the discharge pressure Pd and the suction pressure Ps is set to 2 to 6, and

a ratio (d/D) of a diameter D of said orbiting mirror plate of said orbiting scroll and an outer diameter d of said annular seal is set greater than 0.5.

2. The scroll compressor according to claim 1, wherein a back pressure Δ

P (=Pm−

Ps) applied to said outer region divided by said annular seal is set such that a ratio (Δ

P/Po) of the back pressure Δ

P and a saturation vapor pressure Po when said refrigerant gas is at 0°

C. is substantially a constant value and 0.2 or lower.

3. The scroll compressor according to claim 2, wherein said refrigerant gas sucked into said suction space includes liquid refrigerant having dryness parameter of 0.5 or less.

4. The scroll compressor according to claim 2, wherein carbon dioxide is used as said refrigerant.

5. The scroll compressor according to claim 1, wherein said refrigerant gas sucked into said suction space includes liquid refrigerant having dryness parameter of 0.5 or less.

6. The scroll compressor according to claim 1, wherein carbon dioxide is used as said refrigerant.