| 摘要 |
1,233,982. Hydrostatic transmission. POCLAIN. 16 April, 1969 [19 April, 1968], No. 19402/69. Heading F2D. In a vehicle hydrostatic transmission comprising pumps 1 and 2 supplying respective sets of wheel-driving motors 3 and 4 through lines 7 and 8, the motor exhaust lines 23, 24 are joined at 25 and have a variable restrictor 22 adjusted by the higher delivery pressure in lines 7 or 8 via a shuttle valve 27 so that should either of two reversing valves 35, 36, e.g. valve 35, be opened to allow pump 1 to additionally supply an actuator 33, the consequent drop in pressure in line 7 has no effect on restrictor 22 which is maintained fully open by line 8 pressure and motors 4 continue driving, but should the pressure in both lines 7 and 8 drop, e.g. due to overrun, the restrictor is moved towards its closed position by a spring 22a to restrict the motor exhaust and to provide engine braking. One-way valves 17 connect the exhaust line 16 to motor delivery and return lines 11-14 to supply make-up fluid when the pressure in these lines falls below a predetermined value determined by a relief valve 18 in line 16. Reversing valves 9 and 10 for the motors 3, 4 are interconnected and operated by a lever 39. The actuators 33, 34 may be in parallel with the pumps 1 and 2 rather than in series therewith. |
