| 摘要 |
PURPOSE:To prevent generations of cavitation and choking sound by a method wherein the land section of a sleeve valve member, rotatable relatively with respect to the rotary valve member, is provided with a long groove and a communicating hole to secure sufficiently the flow path area of a supplying port for pressure fluid. CONSTITUTION:When a steering torque is applied to a steering shaft to twist a torsion bar 25 and rotate the rotary valve member 22 relatively with respect to the sleeve valve member 21, the opening area of a choking section 50 between a supplying hole 29 and one of distributing holes 32 is increased while the opening area of the choking section 51 between the supplying hole 29 and the other distributing hole 31 is decreased. When the opening area of the choking section 50 is larger than the same area of the choking section 51, the pressure fluid flows into the right chamber 16b of a power cylinder 16 through the choking section 50 and the distributing hole 32 to move a rack shaft 14 to the left. In this case, the flow path area of the supplying hole 29 is enlarged by the long groove 29a having a smaller width than the land section 28 and the communicating hole 29b having a diameter larger than the width of the long groove 29a, therefore, the flow path area of the supplying port for the pressure fluid may be secured sufficiently. |
