Radial piston hydraulic pump or motor with low loss reaction linkage

Claim 2

In a radial piston pump-motor of the type including a pintle shaft, a cylinder block rotatably mounted on said shaft and having cylinders progressively positioned fluid flow communication with the high and low pressure manifolds of said shaft, piston members reciprocably mounted in sealing relation of said cylinders, and a reaction assembly member rotatable about an axis parallel with but offset from the rotational axis of said block, the improvement which comprises piston operating linkage means interposed between said piston members and said reaction assembly for transmitting forces therebetween, said linkage means each comprising at least one parallel pair of Scott-Russell linkage assemblies, each member of each said pair having a link portion pivotally secured to a piston member, the lines between said pivotal connections to each piston of each pair being at all times perpendicular to the axis of rotation of said block.

Claim 3

The device of claim 1 wherein said linkages include a common slide block portion.

Claim 4

The device of claim 2 wherein said reaction assembly includes a slideway and said slide block portion is journalled in said slideway for movement toward and away from the axis of rotation of said reaction assembly.

Claim 5

The device in accordance with claim 2 and including tandem pairs of parallel Scott-Russell linkages, said pairs being located at opposite sides of a plane extending through the axes of said cylinders.

Claim 6

The device of claim 4 wherein said pistons are cup-shaped and outwardly lap said radial outer ends of said cylinders, at least one sealing ring being disposed between the lapping portions oF said pistons and cylinders.

Claim 7

The device of claim 1 wherein said pistons include guide portions and said Scott-Russell linkages include slide block portions reciprocably mounted on said guide portions for movement axially of said cylinders.

Claim 8

The device of claim 2 wherein said Scott-Russell linkages include long links and short links and the radial outermost ends of said long links are fixed to the slide block portion of said linkages, the radial innermost ends of said long links are fixed to said pistons, and the free ends of said short links are pivotally connected to said reaction assembly.

Claim 9

The device of claim 7 wherein said slide block portion of said linkages are mounted in guideways formed in said reaction assembly, said guideways cooperating with said block for limiting movement of said block to a direction which is radial of said reaction assembly.

Claim 10

The device of claim 8 wherein each said piston is controlled by two pairs of parallel Scott-Russell linkages arranged in tandem to opposite sides of said piston, the points of connection of said pairs to said piston being equally spaced from a plane common with the axes of said cylinders.

Claim 11

The device of claim 1 wherein said pump or motor includes a drive shaft connected to said reaction assembly.

Claim 12

A hydraulic pump-motor device comprising a pintle shaft, a cylinder block mounted for rotation on said shaft, a plurality of piston members mounted on said block for reciprocal movement radially of said block, said piston members and block defining a plurality of variable displacement chambers, porting means in said block for sequentially connecting said chambers with high and low pressure manifold areas of said pintle as said block rotates about said shaft, a reaction assembly rotatable relative to said shaft about an axis displaced from but parallel to the axis of rotation of said block, Scott-Russell linkage means interposed between each of said pistons and said reaction assembly, said linkage means each including a guide member mounted on said reaction ring for reciprocal movement radially with respect to the axis of rotation of said reaction assembly, a pair of parallel long links having their distal ends pivotally connected respectively to a piston member and a guide member, a pair of parallel short links having their ends pivotally connected respectively midway between the pivots of said long links and to said reaction assembly at points equidistant from the axis of rotation thereof, the effective length of said short links being one half the effective length of said long links.

Claim 13

A hydraulic pump-motor device comprising a pintle shaft, a cylinder block mounted for rotation on said shaft, a plurality of piston members mounted on said block for reciprocal movement radially of said block, said piston members and block defining a plurality of variable displacement chambers, porting means in said block for sequentially connecting said chambers with high and low pressure manifold areas of said pintle as said block rotates about said shaft, a reaction assembly rotatable relative to said shaft about an axis displaced from but parallel to the axis of rotation of said block, Scott-Russell linkage means interposed between each of said pistons and said reaction assembly, said linkage means each including a guide member mounted on said reaction ring for reciprocal movement radially with respect to the axis of rotation of said reaction assembly, a pair of parallel long links having their distal ends pivotally connected respectively to a piston member and a guide member, a pair of parallel short links having their ends pivotally connected respectively midway between the pivots of said long links and to said reaction assembly at points equidistant from the axis of rotation thereof, the effective length of said short links being one half the effective length of said long links.

Claim 14

The device of claim 11 wherein said linkage comprises two parallel pairs of said links, said pairs being located in planes parallel to and equally spaced from a plane extending through the axes of said cylinders.

Claim 15

A hydraulic pump-motor device comprising a pintle shaft, a cylinder block mounted for rotation on said shaft, a plurality of piston members mounted for reciprocal movement radially of said block, said piston members and block defining a plurality of variable displacement chambers, porting means in said block for sequentially connecting said chambers with high and low pressure manifold areas of said pintle as said block rotates about said shaft, a reaction assembly comprising a spaced pair of reaction plates one to each side of said block, said plates being mounted for rotation about a common axis parallel with and displaced from the axis of said block, said plates each including a plurality of guideways, in number corresponding to the number of said piston means, a plurality of stabilizers having their opposed end portions slidably received in a guideway in both said plates, said stabilizers being carried in said guideways for reciprocal movement radially relative to said common axis, a pair of pivot pins extending from each side of each said piston means, said pins having their axes parallel with said common axis, a Scott-Russell linkage means including a pair of parallel long lInks to each side of said pistons, said links having their inner ends pivotally connected to said pins, the outer ends of said parallel long links being pivotally connected to said stabilizers, a pair of short parallel links to each side of said piston means, said short links having their ends pivotally connected respectively midway between the pivots of said long links and to one of said reaction plates, the points of connection of said short links to said plates being equidistant from the axis of rotation of said plates, the effective length of said short links being one half the effective length of said long links.

Claim 16

A hydraulic pump-motor device comprising a pintle shaft, a cylinder block mounted for rotation on said shaft, a plurality of piston members mounted for reciprocal movement radially of said block, said piston members and block defining a plurality of variable displacement chambers, porting means in said block for sequentially connecting said chambers with high and low pressure manifold areas of said pintle as said block rotates about said shaft, a reaction assembly comprising a spaced pair of reaction plates one to each side of said block, said plates being mounted for rotation about a common axis parallel with and displaced from the axis of said block, said plates each including a plurality of guideways, in number corresponding to the number of said piston means, a plurality of stabilizers having their opposed end portions slidably received in a guideway in both said plates, said stabilizers being carried in said guideways for reciprocal movement radially relative to said common axis, a pair of pivot pins extending from each side of each said piston means, said pins having their axes parallel with said common axis, a Scott-Russell linkage means including a pair of parallel long lInks to each side of said pistons, said links having their inner ends pivotally connected to said pins, the outer ends of said parallel long links being pivotally connected to said stabilizers, a pair of short parallel links to each side of said piston means, said short links having their ends pivotally connected respectively midway between the pivots of said long links and to one of said reaction plates, the points of connection of said short links to said plates being equidistant from the axis of rotation of said plates, the effective length of said short links being one half the effective length of said long links.