# US 5,702,241 A · Scroll-type fluid displacement apparatus having sealing means for central portions of the wraps

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- Number: US 5,702,241 A
- Document ID: US5702241A
- Status: Granted
- Kind: A
- Application number: 08/633,441
- Filed: 1996-04-17
- Granted: 1997-12-30
- Earliest claimed: 1995-04-19
- Assignees: Sanden Corporation
- Inventors: Takayuki Matsumoto; Yasuomi Matsumoto; Hiroshi Fujita
- Web page: https://patentgrep.com/patent/US5702241A

## CPC

- F04C 27/005: {Axial sealings for working fluid}
- F04C: ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS (engines F03C); ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS

## Abstract

A scroll-type fluid displacement apparatus includes a first and a second scroll, each having an end plate and a spiral wrap extending from one side of the end plate. The spiral wraps interfit at an angular and radial offset to make a plurality of line contacts which define a pair of fluid pockets. A driving mechanism is operatively connected to the first scroll to orbit the first scroll relative to the second scroll while preventing rotation of the second scroll, to thereby change the volume of the pair of fluid pockets. Sealing elements are disposed in the axial ends of the spiral wraps for sealing a central portion of fluid pockets defined by the spiral wraps. Thus, the axial sealing of fluid pocket formed between the orbiting and fixed scroll is more secure in all process from the suction to the discharge stage. Further, the volumetric efficiency of the compressor increases.

## Claims

### Claim 1

A scroll-type fluid displacement apparatus comprising:
a pair of scrolls each having an end plate and a spiral wrap extending from a side of said end plate, said spiral wraps interfitting at an angular and radial offset to form a plurality of line contacts which define at least one pair of fluid pockets;
a driving mechanism operatively connected to a first scroll of said scrolls to orbit said first scroll relative to a second scroll of said scrolls, while preventing rotation of said second scroll, to thereby change a volume of said at least one pair of fluid pockets; and
sealing means disposed in at least one axial end of said spiral wraps for sealing said at least one pair of fluid pocket when defined by a central portion of said spiral wraps, said sealing means including a protruding portion protruding from said at least one axial end of said spiral wraps, wherein a height of said protruding portion increases towards a radial inner end of said spiral wraps.

### Claim 2 (depends on 1)

The scroll-type fluid displacement apparatus of claim 1, wherein said sealing means includes a groove formed in an axial end surface of said spiral wrap along a spiral curve and a sealing element disposed within said groove, such that an axial end of said sealing element extends above an axial end of said wrap at a radial inner end of said wrap.

### Claim 3 (depends on 2)

The scroll-type fluid displacement apparatus of claim 2, wherein said groove includes at least one step therein, such that a depth of said groove is reduced at a radial inner end of said spiral wrap.

### Claim 4 (depends on 2)

The scroll-type fluid displacement apparatus of claim 2, wherein said groove has a plurality of steps reducing a depth of said groove as said groove approaches a radial inner end of said spiral wrap.

### Claim 5 (depends on 2)

The scroll-type fluid displacement apparatus of claim 2, wherein a thickness of said sealing element increases as said groove approaches a radial inner end of said spiral wrap.

### Claim 6 (depends on 2)

The scroll-type fluid displacement apparatus of claim 2, wherein said sealing element includes at least one step portion, such that a thickness of said sealing element increases at a radial inner end of said spiral wrap.