Patent ID: 6468045
Filing Date: 2002-10-22
Classification: F01C

Abstract:
A rotary piston pump, comprising a cylinder block, a front end cover and a rear end cover fixed to a front end surface and a rear end surface of the cylinder block respectively; a cam rotor fitted in an inner chamber of the cylinder block, the cam rotor having a portion which comes into sliding contact with an inner wall of the cylinder block so as to form an axially extending sealing region; a shaft, said cam rotor being mounted on the shaft and being rotatable therewith; a separating system, which is formed between the circumferential surface of the cam rotor and the inner surface of the cylinder block, for separating an axially extending sealed chamber into an induction chamber and an exhaustion chamber; an inlet and an outlet provided on the two sides of the separating system and communicated with the induction chamber and the exhaustion chamber respectively, wherein said separating system comprises:an axially extending circular arc-shaped recess formed in the inner wall of said cylinder block, a central axis of the recess being parallel to an axis of the inner chamber of said cylinder block; a cylinder provided in the recess, said cylinder being a free cylinder, in an assembled state of the separating system, the cylinder being substantially co-axial with the circular arc-shaped recess and an axially extending circular gap being formed between a circumference of the cylinder and the circular surface of the recess; a separating member fitted into said circular gap, said separating member being movable circumferentially independently of said cylinder and being movable circumferentially in the circular gap; and biasing means for biasing the separating member towards the cam rotor.