Hydraulic roller motor

Claim 1

A rotary positive displacement hydraulic motor comprising a cylindrical rotor embodying in its circumferencial periphery off rotor centre line axially extending angled slots, the trailing face of each slot embodying in its periphery one or more hydraulic fluid directing recesses which have a bottom surface extending obliquely from the rotor's periphery into the trailing face of the said angled slots, said fluid directing recesses acting in combination with the internally profiled housing's inlet ports to lead fluid pressure and flow via the trailing slot face and lateral slot to roller clearance to the under-belly of a roller lodged freely in the slot, said roller being slidably confined longitudinally but having a lateral clearance when retracted of probably one millimeter dependent entirely on the volume of fluid embodied in said slot which must be exhausted from underneath the roller as the roller is forced to retract into its slot as it passes through the exhaust phase of the working cycle, said rotor and rollers being mounted for free axial rotation into an internally recessed and concentrically profiled contra rotating housing, means connecting the rotor and housing together such that clockwise rotation of one will produce anti-clockwise rotation of the other, said profile being circumferentially divided into a number of equally spaced stations, each station comprising retracted sealing, fluid inlet, driving and exhaust section, inlet port fluid flow and pressure being directed at the required velocity in combination with the fluid directing recesses contained in the rotor's periphery acts to cause the retracted rollers as they pass through or almost through, the incoming inlet fluid to change from the trailing slot face to the leading slot face while still retracted causing the fluid pressure driven rollers to leave their retracted positions and to rise away from the rotor axis while remaining in constant contact with both the leading rotor slot face and the internal housing's profile and to lift their longitudinal axis above the periphery of the cylindrical rotor exposing the underbelly of the now radial extended rollers to fluid flow and pressure which holds them in their operative position in which they produce useful rotation and torque on both the rotor and profiled housing in both clockwise and anti-clockwise direction, said profiled housing embodying exhaust port means whereat the driven driving rollers change from the leading slot face to the trailing slot face acting to cause much of the fluid present under the said rollers and embodied in the external rotors axially extended slots to be exhausted through the lateral clearance gap between slots and rollers and radially in advance of the retracting rollers, said port means being radially probably as long as the pitch between any two rollers but preferably radially longer allowing two or more rollers to be exhausting into the exhaust section simultaneously as they retract into their embodying slots where they are supported in said embodying slots by an under roller cushion of high pressure mud, which mud, because of the pressure drop differential between inlet and exhaust ports, acts to hold said rollers in rolling, sliding and sealing contact between the trailing side of the rollers embodying slots and the smallest concentric periphery of the internal housing.