GB756073A - Infinitely variable hydraulic gear unit - Google Patents

Abstract

756,073. Hydraulic couplings; fluid-pressure servomotor control systems. KLATTE, T., [trading as KLATTE, T., [Firm of]]. Dec. 15, 1953 [Dec. 17, 1952], No. 34937/53. Classes 69 (2) and 135. A hydraulic infinitely variable speed gear comprises a pump and motor of the internal gear type. An input shaft 1 carries the inner wheel 2 of the pump, the external wheel 14 being rotatably mounted in bearing rings 5, 6 fast with an output shaft 7. The output shaft 7 carries the inner wheel 32 of the motor, the outer wheel 33 being rotatably mounted in bearing rings 37, 38 fast with a housing 11. Oil passes through a hollow shaft and slots in the inner wheel of both the pump and the motor, to and from the spaces between the gear teeth, and the oil flow is controlled by rotary distributer valves 21, 47. Valves 21, 47 are stationary relatively to the output shaft 7 and the housing 11, respectively, except when they are rotated for adjustment purposes. This is effected by a centrifugal governor 52 driven from shaft 1 and controlling the position of a piston 60 which, through suitable linkages, controls the position of the valves. Starting.-With the prime mover idling, piston 60 is in its upper end position and valve 21 is thereby set to give zero output and to allow the oil to circulate idly in the pump. The valve 47 is set for maximum flow. As the speed of the shaft 1 increases, piston 60 descends under the control of the governor, and the pump output is increased consequentially, the effective stroke space of the motor being simultaneously decreased. At a speed determined by the governor, valve 21 reaches the position giving maximum output from the pump, and valve 47 reaches the position in which it cuts off the supply to the motor and allows the oil to circulate idly in the motor. The internal and external wheels of the pump and the bearing rings 5, 6 therefore rotate solid, and a direct drive is obtained. To obviate any power losses the pump output may be cut off by a valve 85 sliding in the valve 21, and the motor may be emptied. Braking.-The prime mover is set for idling, then, by means of a lever 91 and an associated linkage, the valve 47 is turned beyond its zero external flow position and the motor acts as a pump, the oil discharging through a safety valve 101 when the maximum pressure is exceeded. Reverse running.-The prime mover is adjusted for idle running and lever 91 is moved into an end position in .which the valve 47 is turned through 180 degrees from its starting position. On opening the throttle of the prime mover, the pump therefore drives the oil motor in reverse.