Patent ID: 9358967
Filing Date: 2016-06-07
CPC Classification: B60T,F04C

Claim Text:
1. A rotary pump comprising: a rotating unit having an outer rotor provided with internal teeth on an inner periphery thereof, an inner rotor provided with external teeth on an outer periphery thereof meshed with the internal teeth and which rotates around a drive shaft on an axis, and a plurality of gaps formed between the meshed internal teeth and the external teeth; a casing, formed to cover the rotating unit, the casing having a first side plate disposed on one axial end surface side of the rotating unit, a second side plate disposed on another axial end surface side of the rotating unit which has a contacting surface to axial end surfaces of the inner rotor and the outer rotor that forms a mechanical seal, and a central plate disposed so as to surround an outer periphery of the outer rotor; an inlet port for sucking fluid into the rotating unit and a discharge port for discharging the fluid from the rotating unit, both provided in the casing; a first sealing member that divides spaces between the rotating unit and the first side plate into a low-pressure part connected to the inlet port and a high-pressure part connected to the discharge port; a second sealing member that divides a gap formed between the outer periphery of the outer rotor and the central plate into the low-pressure part connected to the inlet port and the high-pressure part connected to the discharge port; and a linear groove having a communication portion formed on a surface where the mechanical seal is performed among surfaces of the second side plate and connected to the high-pressure part of the gap, and a linear portion connected to the communication portion and which extends between the internal teeth and the outer periphery of the outer rotor; wherein a center line is defined as a line passing through a rotation axis of the outer rotor and a rotation axis of the inner rotor, the linear groove is provided on an inlet port side of the center line; and the entire portion of the linear groove is disposed on an end surface of the second side plate on the inlet port side of the center line and in a position radially outside of the plurality of gaps.