Rotary expansible chamber devices – Multistage
Reexamination Certificate
1999-10-28
2001-07-31
Vrablik, John J. (Department: 3748)
Rotary expansible chamber devices
Multistage
C418S055500, C418S060000, C418S083000, C418S188000, C417S410500
Reexamination Certificate
active
06267572
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a scroll fluid machine suitable for use in an air compressor, a vacuum pump, etc. by way of example.
In general, a scroll fluid machine has a casing and a fixed scroll member provided in the casing. A driving shaft is rotatably provided in the casing. An orbiting scroll member is orbitably provided on the distal end of the driving shaft in the casing to come in sliding contact with the fixed scroll member in the axial direction. A plurality of compression chambers are defined between the orbiting scroll member and the fixed scroll member [for example, see Japanese Patent Application Unexamined Publication (KOKAI) Nos. 6-26484 (1994) and 9-144674 (1997)].
In this type of conventional scroll fluid machine, the driving shaft is externally driven to rotate, causing the orbiting scroll member to perform an orbiting motion with a predetermined eccentricity with respect to the fixed scroll member, thereby sucking a fluid, e.g. air, from a suction opening provided at the outer periphery of the fixed scroll member, and successively compressing the fluid in the compression chambers formed between the wrap portions of the fixed and orbiting scroll members. Finally, the compressed fluid is discharged to the outside from a discharge opening provided in the center of the fixed scroll member.
Incidentally, in the above-described conventional scroll fluid machine, a crank shaft is provided at the distal end of the driving shaft at a position eccentric with respect to the axis of the driving shaft to orbitably support the orbiting scroll member at the distal end of the driving shaft. The crank shaft is integral with the driving shaft or provided as a member separate from the driving shaft.
Accordingly, the overall length of the driving shaft becomes extra longer by the length of the crank shaft. This causes the whole apparatus to increase in size in the axial direction unfavorably.
In view of the above-described problems with the prior art, an object of the present invention is to provide a scroll fluid machine designed to eliminate the need for a crank shaft for orbitably supporting an orbiting scroll member and to enable a reduction in overall length in the axial direction.
SUMMARY OF THE INVENTION
To attain the above-described object, the present invention provides a scroll fluid machine arranged as stated below.
The scroll fluid machine includes a stationary member having a casing and two fixed scroll members fixedly provided in the casing at both ends of the casing. The two fixed scroll members are centered on the axis of the casing. Each of the fixed scroll members has a spiral wrap portion standing on an end plate. An electric motor is provided in the casing between the two fixed scroll members. The electric motor has a rotor and a stator which are so arranged that their axes extend parallel with the axis of the casing. Two eccentric bearings are provided in association with the two fixed scroll members. Each of the two eccentric bearings includes an outer ring provided between the electric motor and the associated fixed scroll member and fixedly fitted at the outer periphery thereof to the casing. An intermediate ring is rotatably provided at the inner peripheral side of the outer ring. The inner periphery of the intermediate ring has an eccentric axis radially displaced relative to the axis of the outer ring. An inner ring is rotatably provided at the inner peripheral side of the intermediate ring. The inner ring is rotatable about the eccentric axis. A rotating shaft is provided to extend between the intermediate rings of the two eccentric bearings through the rotor of the electric motor. The rotating shaft is formed from a hollow shaft member and rotatable together with the intermediate rings as one unit by the rotor. An orbiting shaft is loosely fitted in the rotating shaft. The axis of the orbiting shaft is coincident with the eccentric axis. The orbiting shaft is fixedly supported by the inner rings of the two eccentric bearings so as to perform an orbiting motion together with the inner rings as one unit. Two orbiting scroll members are connected to both ends of the orbiting shaft to face the fixed scroll members, respectively. Each of the orbiting scroll members has a spiral wrap portion standing on an end plate so as to overlap the wrap portion of the associated fixed scroll member to define a plurality of compression chambers. In addition, a rotation preventing mechanism is provided between at least either one of the two orbiting scroll members and the stationary member to prevent rotation of the orbiting scroll members.
REFERENCES:
patent: 3924977 (1975-12-01), McCullough
patent: 4515539 (1985-05-01), Morishita
patent: 4553913 (1985-11-01), Morishita et al.
patent: 5447418 (1995-09-01), Takeda et al.
patent: 6030192 (2000-02-01), Hill et al.
patent: 57-24486 (1982-02-01), None
patent: 64-29688 (1989-01-01), None
patent: 4-121478 (1992-04-01), None
patent: 4-121474 (1992-04-01), None
Suefuji Kazutaka
Takahashi Mineo
Torigoe Taisuke
Tokico Ltd.
Vrablik John J.
Wenderoth , Lind & Ponack, L.L.P.
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