Gear pump

Abstract

A gear pump having a suction port, first and second discharge ports, an inner rotor having external teeth, an outer rotor having internal teeth such that the number of the internal teeth is larger than that of the external teeth of the inner rotor, and inter-tooth chambers defined by the external teeth and the internal teeth. The first and second discharge ports are in communication with the inter-tooth chamber whose volume is decreased along with rotation of the inner rotor etc. An inter-tooth chamber which has been brought out of communication with the second discharge port is brought into communication with the suction port while the volume is decreasing. The volume of the inter-tooth chamber which has been brought out of communication with the second discharge port is increased after at least a part of the inter-tooth chamber has been brought into communication with the suction port.

Description

TECHNICAL FIELD[0001]The present disclosure relates to a gear pump that includes an inner rotor having a plurality of external teeth and an outer rotor having a plurality of internal teeth and disposed eccentrically with respect to the inner rotor.BACKGROUND ART[0002]There has hitherto been known a gear pump that includes an inner rotor having n external teeth, an outer rotor having (n+1) internal teeth meshed with the external teeth, and a casing formed with a suction port and a discharge port (see Patent Document 1, for example). In the gear pump, a first angle formed by a first line that connects between the center of rotation of the inner rotor and the tooth tip of the external teeth and a second line that connects between the center of rotation and a meshing portion of the external teeth is 1.4 times or more and 1.8 times or less a second angle formed by a third line that connects between the center of rotation and the tooth bottom of the external teeth and the second line. The...

AI Technical Summary

Benefits of technology

[0007]In the gear pump, the inter-tooth chamber which has been brought out of communication with the discharge port is brought into communication with the suction port while the volume of the inter-tooth chamber is decreased along with rotation of the inner rotor and the outer rotor. Consequently, a fluid is discharged from the inter-tooth chamber which has been brought out of communication with the discharge port to the suction port with the volume of the inter-tooth chamber decreased along with rotation of the inner rotor etc. The volume of the inter-tooth chamber which has been brought out of communication with the discharge port is increased after the inter-tooth chamber has been brought into communication with the suction port. That is, the volume of the inter-tooth cha...

Problems solved by technology

Even if the configuration described in Patent Document 1 is adopted, however, it is still difficult to completely suppress an inflow of a fluid into the cell with the s...

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