Patent ID: 6474752
Filing Date: 2002-11-05
Classification: B60T,F04C

Abstract:
A rotary pump comprising:a drive shaft; a rotating unit constituted by an outer rotor having an inner teeth portion on its inner periphery and an inner rotor having an outer teeth portion on its outer periphery, said inner rotor being rotated by said drive shaft, wherein a plurality of gap portions are formed between said inner teeth portion and said outer teeth portion by mesh thereof and each of said gap portions changes from a large volume to a small volume and vice versa when said rotating unit rotates; and a casing for containing said rotating unit, said casing having an opening for allowing said drive shaft to be inserted thereinto, an intake port extending along a side surface of said rotating unit perpendicular to an axis of said drive shaft over a part of said gap portions for introducing brake fluid in said part of the gap portions, and a discharge port extending along said side surface of said rotating unit perpendicular to said axis of the drive shaft over another part of said gap portions for discharging brake fluid from said another part of the gap portions, wherein a differential pressure between a pressure at said intake port and a pressure at said discharge port is maintained by a first closed gap portion of which a volume becomes a maximum and a second closed gap portion of which a volume becomes a minimum among said gap portions whereby the gap portions coming just after the second closed gap portion to the first closed gap portion perform a suction stroke and the gap portions coming just after the first closed gap portion to the second gap portion perform a discharge stroke; a low pressure side communicating path formed in said casing so as to extend from said intake port to an outer periphery of said outer rotor on a side of said intake port; a high pressure side communicating path formed in said casing so as to extend from said discharge port to the outer periphery of said outer rotor on a side of said discharge port; a first seal device for restraining flow of a fluid between said high pressure side communicating path and said low pressure side communicating path on the outer periphery of said the outer rotor on a side where said first closed gap portion is formed; and a second seal device for restraining flow of the fluid between said high pressure side communicating path and said low pressure side communicating path on the outer periphery of said outer rotor on a side where said second closed gap portion is formed.