Patent ID: 9101970
Filing Date: 2015-08-11
Classification: B21C,B21D

Abstract:
1. A groove processing device for processing a cylinder groove to an inner circumference of a cylinder, the cylinder groove protruding from an inner circumferential surface toward an outer circumferential surface side and extending in a direction of a center line of the cylinder, the device comprising: a groove processing member that moves in the direction of the center line while contacting the inner circumference of the cylinder, the groove processing member including a first groove processing portion and a second groove processing portion in a single body, the first groove processing portion processing both end portions of the cylinder groove in a circumferential direction thereof, and the second groove processing portion processing a center portion of the cylinder groove in the circumferential direction thereof, wherein an outermost circumferential portion of each of the first groove processing portion and the second groove processing portion is formed to be a chevron shape so that a center portion thereof in the circumferential direction of the cylinder protrudes, and an inclination angle from a vertex portion in the outermost circumferential portion of the first groove processing portion is larger than an inclination angle from a vertex portion in the outermost circumferential portion of the second groove processing portion.