GB1346474A - Internally meshing gear pumps - Google Patents

Abstract

1346474 Gear pumps O ECKERLE 15 July 1971 [17 July 1970] 33214/71 Heading F1F In an internally meshing gear pump, a sheet metal plate 9 clamped between the central housing 8 and an end cover 2 and pressure loaded over an area 13 defined by an O-ring 12 by pressure fluid via a bore 14 provides axial sealing of the pump chamber, and the ring gear 7 is radially biased against the pinion 4 and a pivoted filling piece 5 which may be lapped in by pressure fluid fed to a space 15 delimited by spring-pressed vanes 16, 17 mounted in the housing 8. Bores 21a, 21b return lubricating fluid from the bearings of pinion shaft 1 to the suction side of the pump. The ring gear may be mounted in a bearing ring (23), Figs. 3 and 4, (not shown) which is located with a small amount of freedom within the housing by means of a pair of fixed axially or radially inclined pins (24, 25) or (31, 32), Fig. 5, (not shown), engaging in diametrically opposite slots in the ring (23), which is radially biased, the vanes being replaced by rubber strips (26) located in grooves in the ring (23). The ring may be further guided by lugs (35) in the housing cooperating with slots (36) in the ring, Figs. 6 and 7, (not shown). In another embodiment Fig. 8, the plate 41 is located in a recess in the associated end plate, the ring gear 40 being radially loaded by high pressure fluid supplied to the spaces between pairs of shoes 49 via bores 58, the space 65 between the centre pair of shoes 49 being connected to fluid at suction pressure via channels 67, 68. Apertures 50 and 51 in the plate 41 connected respectively to the low pressure side of the pump and to the high pressure zone 52 loading the plate 41 regulate the pressure build-up in the pump together with intermediate throttled apertures 53. Fluid trapped between the engaging teeth is relieved via aperture 54 in plate 41 and returned to the working spaces via bore 55. A pocket 57 in the suction region of the pump communicates with a helical groove 56 so that fluid may be drawn therethrough to lubricate the shaft. Precise axial alignment of the central housing and the end covers may be ensured by providing the central housing with shoulders engageable with correspondingly shaped recesses in the end covers, Fig. 14, (not shown) or pins (67) located in through bores (73) in the end covers are made of a cold workable material and are punched into conical recesses (72) in the central housing, Fig. 12 and 13, (not shown).