摘要 |
A variable capacity pump/motor (100) has a meshing internal and external gear set (128, 124) disposed between an upper mandrel (140) and a lower mandrel (110), each including a flange (120, 144) extending towards the gears to divide a pump/motor chamber into suction and discharge chambers. The outer gear (126) is fixed and the internal gear (128) is axially moveable with respect thereto. The inner gear (128) and the upper mandrel (140) move in response to changing pressures in the casing (102), allowing the motor to vary displacement and the pump to vary its output based on supplied fluid pressure or based on the speed of the prime mover (20). An external configuration (200) includes a pair of meshing gears (214, 218) mounted on separate shafts (222, 224) in a casing (202). One gear (214) is fixed and the other (218) is axially moveable with respect thereto and moves in response to changing pressures in the casing. Each of the gears is sealed by a seal/bushing (226, 228) on a free end thereof. |