Internal gear pump and internal gear motor

Abstract

This internal gear pump is provided with: an internal gear rotatably fitted in a body; an external gear internally touching and meshing with the internal gear; a filler piece partitioning a liquid feeding space formed between the internal gear and the external gear into a high-pressure region and a low-pressure region; and a sealing member covering both end surfaces in a rotational axis direction of both gears and sealing the liquid feeding space. A communication groove for communicating a surrounded space, surrounded by the filler piece and a tooth groove of at least one of the gears, with the high-pressure region is formed. The communication groove is formed so that, as the rotational phase of both gears advances, the cross section of the communication groove communicating with the surrounded space continuously increases and the rate of the increase goes up in an accelerated manner.

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