Abstract: A fluid pump (10) has a body housing (14) a fluid pumping chamber having a rotatable pumping member (16), a drive shaft (12) which passes through an aperture in the body into the pumping chamber to effect rotation of the pumping member in use, a seal (18) between the pump body and drive shaft to inhibit fluid moving along the shaft out of the pumping chamber, and a dividing shroud (32) operably located between the seal and the rotatable pumping member to divide the fluid pumping chamber (30) between the seal and the rotatable pumping member.

Abstract: A hydrostatic drive comprises a motor and a gerotor pump having its annulus or its rotor axially split into two parts of unequal length, one of the two parts being angularly shiftable relative to the other to enable the drive to be shifted between forward, reverse, and neutral conditions.

Abstract: A compact gerotor pump having reduced axial dimension has an external fixed pump body in which a rotor and annulus set is housed. A drive shaft is provided that is neither fixed nor journalled directly by the pump body. The shaft is secured to the rotor within the body and extends through an opening in an end wall of the body and is secured to the hub of an external drive gear that is journalled by the housing for driven rotation of the drive gear, shaft, and rotor relative to the pump body.

Abstract: A gerotor pump comprises the usual lobed annulus 30 containing the lobed rotor (not shown in FIG. 2) which is journalled on cylindrical boss 36. The boss is free to turn on the eccentric pin 38 between positions controlled by limit pin 42 encountering end abutments. This enables the pump to automatically adjust to the variable direction of drive of the annulus--in this case via coupling 32--so as to be unidirectional in fluid output via flow passages 16 18.

Abstract: Oil pump manufacture is simplified by providing the pump body with a planar unstepped face and achieving radial location by the provision of a bush 22 (FIG. 2) on the pump driven shaft 14, which bush is received in the counterbore 24 of the part journalling the drive shaft 16, i.e. the cylinder block adjacent the end of the drive shaft (crankshaft).

Abstract: A method of setting up the required running tolerances in a gerotor pump having annulus and rotor meshed together and located in a body comprises pressing a cover plate (FIG. 1) or equivalent as an interference fit into the body and then allowing it to relax and recover elastically to set up the required tolerances at axial ends of the gerotor set.

Abstract: A water pump has a bowl like body and a seal across the rim of the body. Coolant leakage through the seal is used to wet the rubbing faces of the seal. Superfluous leakage is collected in the bowl so that it may be evaporated by engine heat.

Abstract: A gerotor pump has a rotatable, lobed rotor with n lobes meshed with a rotable lobed annulus with n+1 lobes, the two being conjointly and relatively rotatable about parallel axes. The lobes of both the rotor and the annulus spiral helically to smooth pressure peaks and reduce noise.

Abstract: An I.C. engine lubrication system comprises a gerotor pump set driven by a gear meshed with another gear on the crankshaft (FIG. 1). This enables pump diameter to be selected for minimum power absorption as compared with prior art arrangements where the gerotor surrounds the crankshaft, and also simplifies pipework particularly on the delivery side of the pump.

Abstract: A gerotor set (FIG. 1) has grooves 108 extending across the end face of the annulus adjacent the outlet port so as to allow flow from each chamber in turn into the outlet at a time when the chamber per se is not yet registered with the outlet, so as to prevent noise due to the trapped volume being compressed when it is unable to escape into either port.

Abstract: A gerotor pump set passages 32 extending parallel to the axis of rotation through the female lobed annulus, and similar passages through the male lobed rotor. These passages enable flow from the fluid inlet to pass into the working chamber such as 43 either directly at the inlet end, or after flow through those passages and through the transfer passage 43 at the opposite axial end to the inlet, without requiring a transfer passage externally of the annulus. the result is better axial filling of the working chambers, in a particularly compact design.

Abstract: A reversible unidirectional flow gerotor pump (FIG. 1) has an externally cylindrical internally lobed rotor (36) internally meshed with an eccentrically located externally lobed male rotor having a smaller number of lobes (40) and the annulus runs in a cylindrical cavity in carrier ring 22 pivoted on pin 20 via slot 24. The carrier ring is located in a cylindrical cavity in the body of the pump and is free to translate along the line 18, with accompanied movement along the line 44, this movement occurring automatically when the direction of rotation of the driven rotor 40 is reversed, and resulting in continued pumping flow in the same direction through the pump.

Abstract: A method of casting a water pump impeller which initially includes the formation of a foam pattern incorporating a former which remains as a part of the impeller, the foam pattern being used to form a mold in which the impeller is cast accompanied by the destruction of the foam pattern.

Abstract: The invention provides a variable output pump of the gerotor type in which one rotor meshes in two side by side annulii which can be aligned for maximum output and turned in opposite directions to be non-aligned for minimum output. The movement is effected by a gear train displaced by a rack which is hydraulically operated by pump pressure. Hence high pressure displaces the rack to result in lower output against lower pressure. A variation is described in which a control spool diverts fluid to either side of the piston according to need and this is displaced in one direction by the derived fluid pressure and in the other direction additionally by spring pressure transferred from the piston position by a lever system. This can give desired pump output/speed results at reduced power consumption.

Abstract: A variable output gerotor oil pump of the kind having a common rotor with n teeth meshed with two axially juxtaposed internally lobed annuli with n+1 teeth has the annuli individually located in eccentrics formed with gear teeth to be turned in opposite directions by a gear drive. The teeth are straight cut, not bevel, and the drive includes an intermediate pinion so that a single shaft turns the eccentrics in opposite directions.

Abstract: A cooling system for an I.C. engine includes a gerotor pump coupling a drive shaft 10 to the fan blades 20. The pump is arranged to self-prime when a by-pass passage 26 connecting the pump with the reservoir is closed by initial movement of the thermostat 34 displacing a tube 36 to close port 38. When primed, the gerotor set will drive the fan at an intermediate speed. Further movement of the thermostat displaces a spool valve 26 to take waist 24 out of register with transfer path 22 so that the pump locks up and the fan is driven at a higher speed.

Abstract: A gerotor pump is arranged for unidirectional flow irrespective of direction of rotation of the pump by arranging for displacement of the axis of eccentricity of the annulus and rotor upon drive reversal, the annulus being mounted in a carrier 14, FIG. 1, with freedom for movement in a first direction within the carrier, while the carrier itself is pivoted (24) in an outer housing 15, the carrier being free for movement in a second direction within the housing. The effect of normal drive of the rotor is to hold the parts in the FIG. 1 position while pumping continues, but in the event of drive reversal a pressure fluctuation causes the annulus to be displaced within the carrier and then the carrier to be displaced within the housing so as to bring the parts to substantially the mirror image of the FIG. 1 position allowing continued pumping in the same direction from inlet to outlet under reversed drive.

Abstract: A gerotor pump of n and n+1 type has the annulus and rotor located in a chamber with one wall provided by a floating coverplate held in place by a spring so that in the event of excess internal pressure the cover can lift to allow cross leakage between the inlet and outlet sides of the pump. FIG. 2 illustrates a typical embodiment.