| 摘要 |
<p>A rotary steering control valve is provided of generally conventional construction having incorporated therein small diameter flow passages to effect throttling of return flow from a power cylinder. The throttling of exhaust from a power steering cylinder is known to be advantageous, e.g., for stifling noise, and the present invention has throttle passages incorporated directly in one of the relatively rotative valve members in such arrangement that when the valve is in neutral position for straight ahead steering, there is circulation of little pressure through the valve without throttling. However, during steering, the throttle passages are aligned in the exhaust circuit from either end of a double acting hydraulic motor so as to achieve exhaust flow throttling. The function is achieved by a novel arrangement of the coacting flow control edges and various grooves of the rotary valve plug and the encompassing sleeve which provide a multiplicity of return flow paths. Such grooves can be machined into the plug and sleeve, several at a time, by broaches and milling cutters in an economical manner.</p> |
