Rotary expansible chamber devices – Working member has planetary or planetating movement – Helical working member – e.g. – scroll
Reexamination Certificate
1998-09-28
2001-01-16
Freay, Charles G. (Department: 3746)
Rotary expansible chamber devices
Working member has planetary or planetating movement
Helical working member, e.g., scroll
C418S057000
Reexamination Certificate
active
06174150
ABSTRACT:
BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT
The present invention relates to a scroll compressor in which a compression chamber is formed between two scrolls with respective scroll wraps and a volume of the compression chamber is decreased to compress a fluid therein by an orbital motion therebetween around an axis, and relates to an air conditioner including the scroll compressor.
JPA Hei-5-263776 discloses a structure for the scroll, in which an axial distance between an orbital scroll and a stationary scroll is increased by a force converting mechanism having a contact between an outer peripheral surface of the stationary scroll and a tapered guide surface of a frame to convert a radial thermal expansion force of the stationary scroll to an axial force urging the stationary scroll axially, when a temperature of the stationary scroll is increased.
JPA Hei-3-11102 discloses a scroll structure in which a pitch between the scroll wraps varies from an radially inside of the scrolls toward an radially outside thereof.
OBJECT AND SUMMARY OF THE INVENTION
An object of the present invention is to provide a scroll compressor in which an excessive contact stress between scrolls is prevented with keeping attitude relation and positional relation therebetween correct.
According to the present invention, a scroll compressor comprises,
two scrolls including respective scroll wraps to form a compression chamber therebetween so that a volume of the compression chamber is decreased to compress a fluid therein by an orbital motion between the scrolls around an axis,
a frame supporting the scrolls thereon,
a drawing force generator generating a drawing force urging axially one of the scrolls toward another one thereof, and
a contacting force limiter bearing at least a part of the drawing force to prevent the at least a part of the drawing force from being born by a contact between the scrolls, when an axial distance between the scrolls is not more than a predetermined axial distance.
Since the at least a part of the drawing force is prevented from being born by the contact between the scrolls when the axial distance between the scrolls is not more than the predetermined axial distance, an excessive contact stress between the scrolls is prevented, and a relationship in attitude and position between the scrolls is kept desirably when the axial distance between the scrolls is not more than the predetermined axial distance. Another or remainder part of the drawing force is born by a contact between the scrolls, for example, by a contact between a front end of wrap and a mirror plate surface.
The contacting force limiter may prevent the axial distance between the scrolls from being less than the predetermined axial distance so that the substantial whole of the drawing force is born by the contacting force limiter to prevent the drawing force from being born by the contact between the scrolls when the axial distance between the scrolls is equal to the predetermined axial distance. The drawing force generator may include a thrust bearing which is connected to the one of the scrolls to apply the at least a part of the drawing force therethrough to the one of the scrolls so that the one of the scrolls is urged axially toward the another one the scrolls, and the contacting force limiter may prevent an axial distance between the another one of the scrolls and the thrust bearing from being less than another predetermined axial distance so that the contacting force limiter bears the at least a part of the drawing force to prevent the at least a part of the drawing force from being born by the contact between the scrolls when the axial distance between the scrolls is not more than the predetermined axial distance.
The contacting force limiter may be fixed axially with respect to the frame and be connected to the one of the scrolls to bear the at least a part of the drawing force so that the at least a part of the drawing force is prevented from being born by the contact between the scrolls. The contacting force limiter fixed axially with respect to the frame and connected to the one of the scrolls keeps an attitude and position of the one of the scrolls desirably. If the one of the scrolls is allowed to move with respect to the contacting force limiter in such a manner that the axial distance between the scrolls is increased, the excessive contact stress between the scrolls is prevented more securely.
The contacting force limiter may be fixed axially with respect to the frame and be connected to the thrust bearing to bear the at least a part of the drawing force so that the at least a part of the drawing force is prevented from being born by the contact between the scrolls when the axial distance between the scrolls is not more than the predetermined axial distance. The contacting force limiter fixed axially with respect to the frame and connected to the thrust bearing keeps an attitude and position of the thrust bearing desirably. If the thrust bearing is allowed to move with respect to the contacting force limiter in such a manner that the axial distance between the another one of the scrolls and the thrust bearing is increased, the excessive contact stress between the scrolls is prevented more securely. If the one of the scrolls is allowed to move with respect to the thrust bearing in such a manner that the axial distance between the scrolls is decreased, the scrolls can contact each other while the at least a part of the drawing force is prevented from being born by the contact between the scrolls.
The drawing force generator includes a spring and/or the fluid (lubricant and/or refrigerant) compressed by the compression chamber, for generating the drawing force. A creep member may be arranged between the one of the scrolls and the contacting force limiter to be deformed plastically in accordance with a lapse of compressor operating time by a compression force therebetween to decrease the axial distance between the scrolls in accordance with the lapse of compressor operating time. It is preferable that the drawing force applied to a relatively radially-outer portion of the scrolls is smaller than the drawing force applied to a relatively radially-inner portion of the scrolls. It is also preferable that the scrolls includes respective mirror plate surfaces which extend substantially parallel to each other and face to the wraps respectively to form the compression chamber, a thickness of each of the wraps varies from the relatively radially-outer portion of the scrolls to the relatively radially-inner portion of the scrolls, and an axially projecting height of each of the wraps from the respective mirror plate surface at the relatively radially-outer portion of the scrolls is larger than that at the relatively radially-inner portion thereof. The creep member may be arranged between the thrust bearing and the contacting force limiter to be deformed plastically in accordance with the lapse of compressor operating time by the compression force therebetween to decrease the axial distance between the another one of scrolls and the thrust bearing in accordance with the lapse of compressor operating time.
The contacting force limiter may be arranged on the another one of scrolls so that the at least a part of the drawing force is applied to the another one of scrolls without passing through the one of scrolls to prevent the at least a part of the drawing force from being born by the contact between the scrolls. If the thrust bearing is rotatable with respect to the frame, an abrasion between the thrust bearing and the one of the scrolls is restrained.
If the contacting force limiter has a positioning surface extending substantially perpendicularly to the axis, one of the scrolls and the drawing force generator has another positioning surface extending substantially perpendicularly to the axis, and a contact between the positioning surfaces bears the at least a part of the drawing force to prevent the at least a part of the drawing force from being born by the contact between the scrolls, a relationship
Kohsokabe Hirokatsu
Matsuo Kazuya
Sekigami Kazuo
Takebayashi Masahiro
Tsubono Isamu
Antonelli Terry Stout & Kraus LLP
Freay Charles G.
Hitachi , Ltd.
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