Patent ID: 11898555
Assignee: KYOCERA CORPORATION
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 14:
15. A plunger pump comprising:
a cylinder having a cylinder chamber, and a first through hole and a second through hole that open on an inner circumferential surface of the cylinder chamber and an outer circumferential surface of the cylinder chamber; and
a plunger that has a front end portion with an outer circumferential surface provided with a notch portion, that is inserted in the cylinder chamber, and that is configured to make a reciprocating motion with respect to the cylinder chamber, wherein
an outer circumferential portion of the plunger has the outer circumferential surface of the plunger, and a helical first groove portion is formed on the outer circumferential surface of the plunger, the helical first groove portion being configured to communicate with at least one of the first through hole and the second through hole,
the inner circumferential surface of the cylinder chamber has a second groove portion configured to communicate with the first groove portion and extending over an entire circumference of the cylinder in a circumferential direction of the cylinder, and
the second groove portion comprises a first side surface and a second side surface opposite to the first side surface and a bottom surface connecting the first side surface and the second side surface, and a maximum grain size of crystal grains on the first side surface and the second side surface is smaller than a maximum grain size of crystal grains on the bottom surface.