| 摘要 |
<p>1,180,344. Valves; hydrostatic transmission. SPERRY RAND CORP. 7 March, 1968 [8 March, 1967], No. 11085/68. Headings F2C, F2D and F2V. A pressure surge control valve for the hydrostatic transmissions of small land vehicles comprises a valve member 81 controlling the communication between an inlet 64 and an outlet 72 and having a hollow cylindrical body portion 82 in which slides a spring-loaded piston 87 to form a chamber 83 connected to the inlet via a restricted passage 84 in the conical nose of the valve member. Pressure increase in the inlet causes an increase in pressure in the chamber 83 to move the piston downwards but due to the restricted passage 84 a pressure differential is formed across the valve member which opens the valve to connect the inlet to the outlet until the differential decreases sufficiently. A pin 85 slidable in the passage 84 acts as a self-cleaning means. In use the valve 15 is connected via check valves 67, 68 and in parallel with an adjustable high-pressure relief valve 70 to the high- and low-pressure lines 12, 13 between a variable displacement swashplate pump 11 and a swashplate motor 14 which lines are also connected by a by-pass valve 74. A make-up gear pump 54 is connected via check valves 57, 58 with the pressure lines 12, 13 and is provided with a pressure relief valve 61 communicating with the reservoir 36.</p> |
