| 摘要 |
<p>1,077,319. Fluid-pressure servomotor systems. TRW Inc. Nov.23, 1965 [Dec. 7, 1964], No.49695/65. Heading G3P. [Also in Division F2] An engine-driven speed-responsive pump 17 discharges to a vehicle steering gear 10 via a flow orifice 42 and a clearance 56 between a cup 49 and an outlet nipple 24; the flow through the primary orifice 42 depends upon the extent to which a spring-loaded valve obturator 37 opens a by-pass 47. The obturator has surfaces 36, 40 which are acted upon by the pressures at the nipple 24 and the pump discharge port 30, respectively, the surface 36 being open to the nipple 24 through an orifice 48. Rising flow speed resulting from increasing engine speed is countered by reducing the pressure on surface 36 and increasing the opening of the by-pass 47, viz advancing flow characteristic. The clearance 56 may be formed inside the nipple 24. In a modification Fig. 3 (not shown) the clearance is not provided and the by-pass is close to the primary orifice so that fluid flowing to the former moves close to the latter so reducing the effectiveness of the primary orifice to give a drooping flow characteristic. An additional dumping port may be provided opening into the valve bore between the obturator lands Fig. 4 (not shown) and which after a given obturator movement is connected to the by-pass. In a further modification Fig. 6 (not shown) the primary orifice has a contoured rod passing therethrough which is attached to the obturator. A ball-type safety-valve sits in the obturator to relieve excess pressure at the rear of the latter to the by-pass.</p> |
