GB1191472A - Improvements in or relating to High Pressure Internally Meshing Gear Pumps or Motors - Google Patents

Abstract

1,191,472. Gear pumps and motors. O. ECKERLE. Aug. 11, 1967, No. 36898/67. Heading F1F. An internally-meshing gear pump (or motor) comprising a driven externally toothed pinion 1, Fig. 2, an internally toothed ring gear 3 meshing therewith and a sickle-shaped filling piece 2 disposed between the gears and wherein the ring gear is mounted solely on the filling piece, includes pressure zones 6<SP>1</SP>, 7<SP>1</SP>, connected to and diametrically opposite the pressure chamber 6, 7 of the pump (or motor) so that resultant forces P R , and T i , applied to the pinion and ring gear respectively are balanced by resultant forces -P R , h and -P i , h in the zones 6<SP>1</SP>, 7<SP>1</SP> respectively. Further, to avoid radial leakage gap losses and compensate for wear it is necessary for the pinion 1 to lie tightly against a part 9 and sealing edges 4, 4<SP>1</SP> or the filling piece 2 and the ring gear to lie tightly against a part 8 and sealing edges 5, 5<SP>1</SP> of the filling piece. To accomplish this it is necessary to apply a force P D , Fig. 3, vertically downwards on the ring gear which tends to urge the edges 4, 4<SP>1</SP> and 5, 5<SP>1</SP> on the filling piece farther downwards so that it becomes necessary for the circular arcs subtended between the edges 4, 4<SP>1</SP> and between the edges 5, 5<SP>1</SP> not to exceed 180 degrees resulting in residual forces # P R , h and # P i , h proportional to the tooth pitch acting on the pinion and ring gear respectively. The force # P R , h may be ignored since it is taken by the pinion shaft bearing but the force # P i , h needs to be compensated for. The resultant of the compensating force -# P i , h and P D is at an angle α, Fig. 5 to the horizontal and at this location a radial piston 13, subjected on its rear face to the pressure in the pressure chamber is disposed. A spring 14 provides the pressing pressure on starting and a bore 15 relieves hydro-statically the sliding between the piston and the ring gear. A slot 10 in the filling piece and a pin 11 fixed to the casing provides for downward movement of the filling piece. Recesses 16, 16<SP>1</SP> on the axial end faces of the filling piece reduces the contact surface between the piece and laterally adjoining elements. Axial sealing of the pressure chamber 6, 7 of the pump is effected by pistons 17, 17<SP>1</SP>, Fig. 7 (not shown) subjected on their rear faces to discharge pressure. Axial compensating pistons may also be provided in the vicinity of the pressure zones 6<SP>1</SP>, 7<SP>1</SP>, to compensate for the axial gaps caused by the pressure in these zones. In a modified embodiment, the separate axial pistons sealing the ends of the pressure zones and the pressure chamber are replaced by a single piston.