| 摘要 |
<p>1448270 Vehicle power steering K-H THOMAS [trading as LANGEN & CO] 15 Nov 1973 [16 Nov 1972] 52993/73 Heading B7H In an arrangement for limiting the reaction in hydraulic servo assisted steering gear the reaction chambers 6, 7, Fig. 1, associated with relatively movable input and output members 3, 2 respectively communicate with associated working chambers of a servomotor (not shown) through a throttling constriction 10, 11 as well as with a common pressure limiting valve 19 through an interposed check valve 16, 17 which opens in the direction towards the pressure limiting valve. In a practical arrangement, Fig. 3, control pistons 43, 44 are operated by tappet members 45, 46 controlled by an actuating member 47 operatively connected to the shaft of a steering wheel 48. The control pistons are adapted to alternatively provide communication between a working chamber 59, 60 and a pressure source 50 or a reservoir T 1 , T 2 . In a manner not shown the valve body 40 is operatively connected with one of the pistonrods 57. Reaction chambers 63, 64 communicate with the working chambers 59, 60 through ducts 65, 67 containing throttling constriction 66, 68 whereas ducts 69, 72 connect the reaction chambers to pressure limiting valve 71 via check valves 70, 73. The valve 71 is operated by fluid which is displaced from annular chamber 77 through throttling notches 79 in the land 75 and which then applies thrust to the end face of land 75. When a predetermined pressure is exceeded the control piston is shifted against a spring 80 and land 76 is forced to uncover a port between chamber 77 and an exhaust duct 78. Alternatively a damped seated valve may be employed.</p> |
