Pumps – Condition responsive control of drive transmission or pump... – Adjustable cam or linkage
Reexamination Certificate
2001-11-28
2003-07-15
Freay, Charles G. (Department: 3746)
Pumps
Condition responsive control of drive transmission or pump...
Adjustable cam or linkage
C417S269000, C277S549000, C277S559000, C277S560000
Reexamination Certificate
active
06592337
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a compressor, more particularly, to a shaft seal for the compressor.
2. Relevant Prior Art
The shaft seal has a first lip ring and a second lip ring along a rotary shaft to separate a high-pressure area from a low-pressure area. The first lip ring and the second lip ring contact a circumferential surface of the rotary shaft to prevent fluid from leaking along the circumferential surface of the rotary shaft from the high-pressure area towards the low-pressure area.
Unexamined Japanese Patent Publications No. 5-149442 and No. 6-300142 disclose a shaft seal with a pair of seal elements that is referred to as a pair of lip rings to prevent fluid from leaking along the circumferential surface of the rotary shaft. The shaft seal is, for example, applied to seal a rotary shaft surface of a compressor which constitutes a refrigerant circuit. In Unexamined Japanese Patent Publication No. 5-149442, the seal elements have concentric circular grooves on a side of the high-pressure area and spiral grooves on a side of the low-pressure area. In Unexamined Japanese Patent Publication No. 6-300142, the seal elements have spiral grooves on a side of the low-pressure area. These spiral grooves each function as a pump which returns fluid from an area between a sliding contact portion of the seal element and a rotary shaft surface to where the fluid originally traveled from.
The compressor has sliding contact portions which require lubrication. To lubricate the sliding contact portions, lubricating oil which flows as well as refrigerant is essential. The lubricating oil is used for lubricating a sliding contact portion of the seal element for a rotary shaft. However, the concentric circular grooves which are disclosed in Unexamined Japanese Patent Publication No. 5-149442 do not draw enough lubricating oil. Therefore, the concentric circular grooves are not effective to satisfactorily lubricate a sliding contact portion of the seal element for a rotary shaft. In addition, since a seal between a rotary shaft and a seal element has to be created only by surface pressure acting therebetween, the surface pressure has to be increased. Because of the increased pressure, the seal element is rapidly worn.
On the other hands the seal element on a side of the high-pressure area disclosed in Unexamined Japanese Patent Publication No. 6-300142 does not have the concentric circular groove. Fluid on the side of the high-pressure area tends to move into a space between a pair of seal elements. The movement of the fluid increases pressure of the fluid in the space. That deforms the seal element made of resin on the side of the low-pressure area. For the above reasons, the sliding contact portion of the seal element is rapidly worn. Therefore, the life of the shaft seal is shortened.
SUMMARY OF THE INVENTION
The present invention addresses a shaft seal with long life for improving reliability.
To achieve the above object, the present invention has following features. A shaft seal seals a rotary shaft surface to prevent fluid from moving between a high-pressure area and a low-pressure area. The rotary shaft has a rotary axis and extends between the high-pressure area and the low-pressure area. The shaft seal has a first lip type ring and a second lip type ring. The first lip type ring is fitted on the side of the high-pressure area of the rotary shaft. The first lip type ring further includes a lip ring, a plurality of first portions and a plurality of second portions. The lip ring is located around the rotary shaft. The lip ring has a ring surface. The first portions are formed on the ring surface to slidably contact the rotary shaft surface and are placed at a first predetermined angle with respect to the rotary axis. The first portions guide the fluid towards a space between the ring surface and the rotary shaft surface as the rotary shaft is rotated. The second portions are formed on the ring surface at a second predetermined angle with respect to the rotary axis. The second portions prevent the fluid in the space from leaking into the low-pressure area. The second lip type ring is fitted on the side of the low-pressure area of the rotary shaft so that leakage of the fluid along the rotary shaft surface is prevented.
REFERENCES:
patent: 6123514 (2000-09-01), Kawaguchi et al.
patent: 2002/0003336 (2002-01-01), Yamada et al.
patent: 0 945 653 (1999-09-01), None
patent: 05-149442 (1993-06-01), None
patent: 06-300142 (1994-10-01), None
patent: 10-252897 (1998-09-01), None
Imai Takayuki
Yamada Takeshi
Yokomachi Naoya
Freay Charles G.
Kabushiki Kaisha Toyota Jidoshokki
Knoble & Yoshida LLC
Sayoc Emmanuel
LandOfFree
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