Patent GB-1075333-A (GB)
Title: Improvements in gear pumps or motors of the internally-meshing type
IPC: F04C15/00
Filed: 1964-07-10
Abstract: 1,075,333. Rotary pumps and motors. ROBERT BOSCH G. m. b. H. July 10, 1964 [July 11, 1963], No. 28487/64. Heading F1F. A reversible rotary pump or motor of the internally-meshing gear type comprises an externally-toothed gear 34 meshing with an internally-toothed gear 35, a shaft 31 attached to the gear 34 being journalled in bearing bushes 40, 41 that are axially movable relative to portions 11, 13 of a housing or casing and integral with wear plates 38, 39, one of which plates is pressed against the sides of the gears to effect sealing by pressure communicated from the high-pressure side of the pump or motor to a region defined by a circular sealing-ring 27, or 28, lodged between the respective plate and the housing. Each of the rings 27, 28 is situated eccentrically relative to the shaft 31 so as to form a passageway between either axially-aligned arcuate ports (29, 29'), Fig. 3 (not shown), in the housing portion 11 and the plate 38, respectively, or axially-aligned arcuate ports (30, 30'), Fig. 4 (not shown), in the housing portion 12 and the plate 39, respectively, the said ports being located at the ends of corresponding helical inlet and outlet passages 18, (19) for working fluid e. g. oil. The plates 38, 39 support a crescentshaped member 37 that is lodged in a space between the gears. Passages 32, 33 for leakage fluid are provided in the shaft 31 and communicate with a passage 26 in the housing portion 12, through which passage said fluid can escape to the low-pressure side of the pump or motor by way of one or other of two non-return valves (46, 47), Fig. 5 (not shown). Alternatively, the pump or motor comprises wear plates (117, 118), Figs. 6 and 7 (not shown), that are axially movable relative to housing portions (101, 103), one or other of the plates being pressed against the gears (114, 115) by pressure communicated from the high-pressure side of the pump or motor to a region defined by a non-circular sealing-ring (127 or 133) lodged between the respective plate and the housing substantially in axial alignment with an arcuate port (124 or 125) in the plate (118). Passages (122, 123) in the plate (118) are in register with the ports (124, 125) and inlet and outlet passages (104, 105) in the housing portion (103), a circular sealing-ring (126) being provided between the said plate and housing portion to seal the passage (123). A port (132) in the plate (117) is in axial alignment with the port (124) and is connected to the region defined by the ring (133) by an axial bore (131) in said plate, a further port (134) in the said plate being in axial alignment with the port (125). The plate (117) is backed by a spacing plate (111) that is in sealing engagement with the ring (133). Leakage fluid is drawn off to the low-pressure side of the pump or motor through an axial groove (109) in the housing portion (101), a groove (128 or 135) in the back of each wear plate, an axial bore (129 or 136), Figs. 8 to 10 (not shown), in each plate containing a non-return valve (130) and either of the ports (124, 134) according to the direction of flow of the working fluid. Rotation of the wear plates is prevented by radial pins (119) that are attached to keys (120) lodged in the groove (109). The ports and passages for the working fluid may be arranged as in the embodiment according to Fig. 1.