| 摘要 |
PURPOSE:To provide a constant steering characteristic in three speed regions by furnishing three different speed conditions, low, middle, and high, in which the pressure oil is throttled through one, the other, and both of the two sets of throttles, and turning into either position selectively. CONSTITUTION:The pressure oil is throttled only by either set of throttles A, B, C, D having a small degree of opening of those throttles provided in an inter-valve flow path 27 under the condition with the same steering resistance during the low speed operation or at a standstill. During the high speed operation, not only by them A, B, C, D, but the pressure oil is throttled by the other set of throttles E, F, H having a large degree of opening with the same steering resistance. In the middle speed operation, the pressure oil is throttled only by the other set of throttles E, F, G, H. Thereby the high responsiveness in steering and the stability can be met. This allows providing a constant steering characteristic in three different speed regions, i.e., low or at standstill, middle, and high speed. |
