Abstract: A reversible gear pump or motor capable of sustained operation under unusually high pressure conditions is provided with a unique diverter plate having pressure-transmitting paths in the ends of the plate which open to the gear teeth on both the high and low pressure sides of the pump or motor. In operation, the high pressure is transmitted through the specially formed paths to areas of the gears on the low pressure side. The pressure acts as a counter force which pushes the gears towards a centered position and reduces bearing loads without increasing the pressure forcing the gears towards one another.

Abstract: Method and apparatus are disclosed for counterbalancing the high pressure forces normally generated in the high pressure fluid region of a rotary pump or motor and exerted against the rotating structure of the pump or motor. By this method and apparatus a portion of the fluid in the high pressure region of the pump housing is transported to a region of the housing interior adjacent to, but out of communication with the low pressure fluid region. This transported high pressure fluid is directed against the rotating structure in the direction of the high pressure fluid region. Consequently, the rotating structure of the pump or motor is less subject to distortion or displacement due to forces generated by fluid in the housing's high pressure fluid region.