| 摘要 |
<p>1487287 Valves DEERE & CO 25 April 1975 [26 April 1974] 17332/75 Heading F2V In a valve for controlling the flow to and from a reversible rotary motor 50, a pair of bores 18, 20 house similar valve units and have recesses 26, 28 connected to opposite sides of the motor and recesses 30, 32 connected to a pressure source 52. In each valve unit a restriction between the ends of a split ring 90 allows the fluid pressure to equalize on opposite sides of a piston 88 so that a closure member 98 thereon closes the communication between inlet recesses 30, 32 and recesses 26, 28 which are connected to work ports 40, 36 respectively. Metering grooves 108 on a further closure member 106 communicate the recesses 26, 28 with a reservoir space 16. On energization of an electromagnetically actuated pilot valve 114, 122, a plunger 118 communicates the chamber below the piston 88 with the reservoir space 16 so that pressure in the recess 30, 32 opens the respective valve member 98 to connect the recesses 30, 26 or 32, 28 via metering grooves 102 on the valve member 98 and closes the communication between the recess 26 or 28 with the reservoir space 16. The motor is thus driven in one direction and can be reversed by actuation of the other pilot valve.</p> |
