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Title:
ROOTS TYPE VACUUM PUMP
Document Type and Number:
Japanese Patent JP2010203422
Kind Code:
A
Abstract:

To provide a roots type vacuum pump that prevents the generation of an abnormal sound by a confining phenomenon of liquid between root rotors and prevents the shortening of a bearing service life caused by the infiltration of moisture into a shaft seal part.

A clearance groove 17 of a cross-sectional shape such as a shape for expanding a clearance with an inner peripheral surface 1a of a casing 1 toward the rotational direction is formed over the total length of respective lobes on a peripheral surface of a position separated by a predetermined dimension to a side in the rotational direction from the center line of the respective lobes 16 of the root rotor 15. The shaft seal part 8 fixes a moisture shake-off ring 30 arranged between a collar 26 and a bearing 9 to a rotary shaft 18 of the root rotor 15 by installing one or a plurality of housing oil seals 25 and the collar 26 in order from a place near to an installation surface 7b to the casing 1 in an inner diameter part of the housing 7. A clearance formed on an opposed surface between the collar 26 and the ring 30 is formed so as to form a labyrinth seal, and a passage 7c for returning the liquid stored in the shaft seal part 8 to a vacuum chamber is arranged at the discharge port side of the housing 7.

COPYRIGHT: (C)2010,JPO&INPIT


Inventors:
YOKOI KOMEI
ITO YOSHINOBU
KATO TOSHIAKI
KATO MASAMI
YOKOI IKUTO
Application Number:
JP2009053046A
Publication Date:
September 16, 2010
Filing Date:
March 06, 2009
Export Citation:
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Assignee:
ANLET CO LTD
International Classes:
F04C18/18; F04C25/02; F04C27/00; F04C29/00
Domestic Patent References:
JPH03130592A
JPS55106389A
JPH0450492A
JPH0571487A
JPS627991A
JPS5458605A
Attorney, Agent or Firm:
三宅 始