GB980918A - Hydraulic pump or motor - Google Patents

Abstract

980,918. Rotary pumps and motors. R. W. BRUNDAGE. Feb. 8, 1961 [March 22, 1960], No. 4764/61. Heading F1F. An internally-meshing gear wheel pump (or motor) of the n and n + 1 lobe type comprises a shaft 16, Fig. 1, supported on spaced-apart bearings, a sealing member 13 forming an integral part of the shaft and having a sealing surface 57 adjacent end faces of an externallytoothed gear 11 keyed to the shaft and an internally-toothed gear 12 rotatable in an eccentric ring 17 which also abuts the sealing member and a manifold member 14 fixedly mounted in the housing H. The manifold member includes an arcuate inlet port 43, Fig. 2, connected to a low pressure inlet 36 and an outlet port 44 connected by a passage 46 with a pump discharge port 37 and provides bearing support for the shaft 16. In operation, pump discharge pressure is communicated to a space 41 in the housing and exerts pressure on annular faces 84, 86 of the sealing member indicated by the vector L in opposition to a force R resulting from a summation of the pressures in the variable volume pumping chambers which force is radially offset by a distance r from the shaft axis. Radial fluid pressure forces within the pumping chambers are represented by a single force U acting normal to the shaft 16 on the centre line of the chambers. The force R applies equal and opposite radial reaction forces to the manifold member 14 and a roller bearing 54 relieving and adding respectively to the reaction forces on these members from the force U. The distances a and b of the bearings from the centre line of the chambers are chosen so that the roller bearing 54 takes approximately 80% of the load which permits the bearing between the manifold member and the shaft to be a low cost sleeve bearing. A sealing ring 75 acted upon by a spring 81 encloses a shaft seal 95. The spring 81 together with fluid pressure acting on an annular surface of the ring 75 externally of an 0 ring 76 urges the sealing ring 75 into sealing engagement with the sealing member 13 and augments the force L to further assist the sealing of the pumping chambers. The areas of the faces 84, 86 is such that the force L is slightly larger than the force R. It is stated that the invention may be applied to a rotary vane type of hydraulic pump (or motor). Specification 958,779 is referred to.