| 摘要 |
PURPOSE:To prevent valve opening characteristics from scattering, by a method wherein the opening of a valve at a starting end and a finishing end is controlled by cooperation of chamfered parts and a valve port. CONSTITUTION:When a main shaft 5 is rotated from a neutral condition, a relative rotational displacement is generated between the shaft 5 and a valve sleeve 16 in accordance with the quantity of torsion of a torsion bar 7 concurrently occurring. The flow-controlling characteristics of the valve at the starting end and the finishing end of a valve operation are determined by the sizes, angles and relative positions of the chamfered parts 50, 51 provided on both sides of each of valve port grooves. Since all of the chamfered parts 50, 51 provided on both sides of each of the valve port grooves 41-44 are produced in a single machining step, and accuracy of positions of each of edges 52, 53 in the circumferential direction of the main shaft 5 depends on the accuracy of profile grinding, so that a considerably high accuracy can be obtained. |
