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US 4,493,622 AGranted
Variable displacement motor
AssigneeTRW Inc.
InventorLaurence L. Miller
Life of this patent
Estimating the term…
Abstract
A hydraulic motor which varies its displacement in accordance with varying torque loads on its output shaft. The motor is biased to a low displacement, low torque, high speed mode, and changes to a high displacement, high torque, low speed mode when the torque load on its output shaft increases. The motor has eccentrically disposed gerotor gears that rotate and orbit relative to each other to expand and contract fluid chambers on opposite sides of a center line of eccentricity. The gerotor gears can change their orientation relative to each other in response to changes in the torque load on the output shaft, changed, in order to change the displacement of the motor.
Claims13
A hydraulic motor comprising:
- an inlet port for receiving high pressure fluid and an exhaust port for exhausting low pressure fluid,
- fluid displacement means comprising relatively rotatable and orbital gerotor gears, said gerotor gears having intermeshing teeth which define fluid chambers that expand and contract as the gerotor gears rotate and orbit relative to each other,
- an output shaft,
- means coupling one of said gerotor gears with said output shaft for applying a torque to said output shaft as said gerotor gears rotate and orbit relative to each other, and
- commutation valve means for directing fluid from said inlet port to some of the fluid chambers defined by said gerotor gears and for directing fluid from other fluid chambers to said exhaust port according to the torque load imposed upon the output shaft,
- said gerotor gears defining a center line of eccentricity which separates expanding chambers from the contracting chambers as the gears rotate and orbit,
- said commutation valve means having a center line of commutation that separates the fluid chambers that are being communicated with said inlet port from the fluid chambers that are being communicated with said exhaust port as the gears rotate and orbit, and
- means associated with said other of said gerotor gears for effecting a change in angular position of said other of gerotor gears with respect to said one of said gerotor gears in response to a change in a torque load on said output shaft for enabling a change in the orientation of the center line of eccentricity of the gear set relative to the center line of commutation of the commutation valve means to thereby change the displacement of said hydraulic motor.
5 more elements
A hydraulic motor comprising
- fluid displacement means comprising relatively rotatable and orbital gerotor gears, and gerotor gears having intermeshing teeth which define fluid chambers that expand and contract as the gerotor gears rotate and orbit relative to each other,
- an output shaft,
- means coupling one of said gerotor gears with said output shaft for applying a torque to said output shaft as said gerotor gears rotate and orbit relative to each other,
- commutation valve means for directing fluid from an inlet port to some of the fluid chambers defined by said gerotor gears and for directing fluid from other fluid chambers to an outlet port according to the torque load imposed upon the output shaft,
- said gerotor gears defining a center line of eccentricity which separates expanding chambers from the contracting chambers as the gears rotate and orbit,
- said comutation valve means having a center line of commutation that separates the fluid chambers that are being communicated with said inlet port from the fluid chambers that are being communicated with said outlet port as gears rotate and orbit,
- means responsive to the torque load on said output shaft for enabling a change in the orientation of the center line of eccentricity of the gear set relative to the center line of commutation of the commutation valve means,
- said gerotor gears including an externally toothed inner gerotor gear and an internally toothed outer gerotor gear having one more tooth than said inner gear, the teeth of said inner and outer gerotor gears meshing to define said fluid chambers, said inner gerotor gear being coupled for joint rotation with said output shaft and eccentrically disposed relative to said outer gear so that said inner gerotor gear can rotate and orbit relative to said outer gerotor gear, said outer gear being rotatable relative to said inner gerotor gear in response to the torque load on said output shaft to change the orientation of the center line of eccentricity of the gear set relative to the center line of commutation of the commutation valve means.
5 more elements
A hydraulic motor including
- a gear set comprising relatively rotatable and orbital gerotor gears, said gerotor gears having intermeshing teeth which define fluid chambers that expand and contract as the gerotor gears rotate and orbit relative to each other,
- an output shaft,
- means coupling one of said gerotor gears with said output shaft for applying a torque to said output shaft as said gerotor gears rotate and orbit relative to each other, the expansion and contraction of the fluid chambers defined by said gerotor gears displacing fluid during each revolution of said output shaft,
- means permitting a change in the orientation of said gerotor gears in response to a change in the torque load on said output shaft to change the displacement as the gerotor gears rotate and orbit relative to each other,
- said gerotor gears being disposed in a housing, said means permitting a change in the orientation of said gerotor gears comprising means for rotatably supporting one of said gerotor gears in said housing and spring means biasing said one gerotor gear toward an orientation in which the motor has a predetermined minimum displacement,
- said one gerotor gear being rotatable in said housing to change the orientation of said gerotor gears and increase the displacement of the motor when the torque load on said output shaft causes a moment to be applied to said one gerotor gear which overcomes the bias of said spring means,
- said gerotor gears comprise an externally toothed inner gerotor gear and an internally toothed outer gerotor gear having one more tooth than said inner gerotor gear, the teeth of said inner and outer gerotor gears meshing to define said fluid chambers, said inner gerotor gear being coupled for joint rotation with said output shaft and being rotatable and orbitally movable relative to said outer gerotor gear, said outer gerotor gear being rotatable relative to said housing to change the orientation of said gerotor gears.
4 more elements
Dependencies are inferred from the claim text.