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

Claim 0:
1. A plunger pump comprising:
a cylinder having a cylinder chamber, and a first through hole and a second through hole that open from an inner circumferential surface of the cylinder chamber toward an outer circumferential surface of the cylinder chamber; and
a plunger inserted in the cylinder chamber and configured to make a reciprocating motion with respect to the cylinder chamber, wherein
an inner circumferential portion of the cylinder has the inner circumferential surface of the cylinder chamber, and a helical first groove portion on the inner circumferential surface, 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 communicating 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.