High-pressure gear pump or gear motor with compensation for clearance and wear

Claim 1

A high pressure gear pump and motor with compensation for play and wear comprising: a housing having parallel intersecting bores therein; a pair of intermeshing gears disposed in said bores and having gear shafts rotatably supported in said housing, one of said gears being a driven gear for the transmission of power into the pump, or from the motor, respectively, and at least one other gear meshing with the driven gear; said housing having a high-pressure and a low-pressure passage at opposite sides of the mesh points of the gears; bearing trunnions being positioned on both sides of said gears; clearance takeup means enclosing the pressure side of said meshing gears both radially and axially, thereby forming a pressure chamber therewith; said clearance takeup means including a plurality of control pistons forming the radial enclosure for said pressure chamber by contacting portions of the gear peripheries to both sides of the gear-meshing point, the width of said control pistons corresponding substantially to that of the gears; a plurality of axial face plates, one on each side of said control pistons and gears, forming the axial enclosure for said pressure chamber; and means connecting each of said control pistons and face plates, respectively, to form a unit in the sense of radial movement; bearing portions for contacting said trunnions and being a part of said face plates; pressure-compensating means adapted to radially move and maintain said takeup means against said gears and against said trunnions in opposition to the operating pressure present within said pressure chamber; said pressure-compensating means being arranged as pressure-compensating zones within said control pistons, said pressure-compensating zones communicating with said pressure chamber.