| 摘要 |
PURPOSE:To make it possible to grind the inner surface of a linear with a substantially constant depth even though the location of a screw shaft serving as a rotating center is some or less displaced, by supplying an air pressure which is regulated by a pressure reducing value, into an air cylinder exerting a pressing force to a grinder. CONSTITUTION:Pressurized air is fed into a grinder to rotate a grind wheel 15 while an air pressure reduced and regulated by an adjustable pressure reducing valve 16 is fed into an air cylinder 9 for a turn table 4 so that the grind wheel 15 is pressed against the inner surface of a cylinder liner 1 at a predetermined pressure to grind the same. In this condition, when a worker turns a hollow bar 17 in the direction M, the rotary table 4, the air cylinder 9, an arm 10 and the grinder 11 are rotated as a one unit body, about a screw shaft 3 which is set at the center of the liner by means of a centering member, and simultaneously they are fed in the axial direction in accordance with the thread pitches of the screw shaft 3 to spirally form an elliptic shape corrugated groove 2' having a substantially constant depth. Thus, even though the screw shaft severing as a rotating center for the grinder is some or less eccentric, it is possible to grind the inner surface of a linear in an elliptic shape with a substantially constant depth. |
