US 4,131,056 AGranted

Pilot controlled variable displacement fluid motor

AssigneeFiat-Allis Construction Machinery, Inc.

InventorHarvey W. Rockwell

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Abstract

A pilot controlled variable displacement fluid motor is disclosed wherein fluid under pressure, received from a fluid pressure source such as a closed-center type system, is convertible selectively into bi-directional rotary motion at infinitely variably controlled speeds and torques. The motor is further characterized in that a change in the positional relationship of an arcuately movable control input member with relation to the position of an arcuately movable power output member, in combination with power transfer means, is effective for adjusting the power output speed to that of the control input member. Furthermore, the torque output is automatically adjusted to the load demand, whereby only the quantity of fluid, required to satisfy the speed selection and the torque demand, at a predetermined pressure level, is used by the motor.

Claims12

Dependent claims

A combination fluid motor and drive unit comprising, in combination, an exterior housing member, a power output member having a portion extending through a part of said housing and journalled for rotation relative to said housing, said drive member including means for supporting at least one output driven gear, at least one output driven gear received on a portion of said power output member and mounted for rotation relative thereto, an output drive gear having portions engaging said driven gear, means positioning said drive gear within said housing and supporting said drive gear for rotation relative to said housing, a cylinder block disposed within said housing and being supported for rotation with respect to said housing, a drive connection between said cylinder block and said drive gear, means engaging said driven gear to cause rotation of said power output member upon rotation of said driven gear, valve means associated with said cylinder block for directing fluid under pressure into said cylinders, a plurality of piston and slipper assemblies each having a portion received within one of the cylinders in said block, at least one torque reaction receiving ring surrounding said piston and cylinder units, said torque reaction receiving ring including an inwardly directed cylindrical raceway for said slipper assemblies, said ring being movable among a plurality of positions including positions of both offset and concentric disposition with respect to said cylinder block to change the torque and directional operating characteristics of said cylinder block, and control means for positioning said ring in a desired one of said plurality of positions.

A pilot controlled variable displacement fluid motor comprising a rotatable motor frame, a stationary housing for rotatingly supporting said frame, a cylinder block co-axially and rotatably carried by said frame, said cylinder block having a plurality of cylinder bores and fluid passages therein, planetary gearing means operatively connecting said frame, said housing and said cylinder block for maintaining a predetermined rotational ratio relationship therebetween, a plurality of pistons reciprocatingly disposed in said bores, a slipper associated with each piston, valve means for receiving fluid from a source of fluid under pressure and distributing said fluid to said cylinder bores and against one end of said pistons, means forming a raceway for said slippers, said raceway being pivotable about an axis which is non-concentric with respect to the center line of said cylinder block so that pivotal movement of said raceway means will vary the stroke of said pistons during rotary motion of said cylinder block, and control means operatively associated with said raceway means for pivoting said raceway means to control the direction of rotation, the speed, and the torque output of said motor.

Dependencies are inferred from the claim text.