Hydraulic pump or motor

Claim 2

A housing for a hydraulic device, said housing having a cavity having spaced parallel end surfaces and a cylindrical bearing surface between said end surfaces, an opening through said housing into said cavity having an axis spaced from the axis of said cylindrical surface, the plane through the two axes defining a neutral axis, said cavity having an inlet and an outlet manifold one on each side of said axis one of said manifolds adapted to be at high hydraulic pressure and the other at low hydraulic pressure, said cylindrical bearing surface having two grooves, each groove adjacent one of the ends of said neutral axis and means communicating said grooves with the high pressure manifold, said cylindrical bearing surface on the side of said neutral axis adapted to be at low pressure having a pair of switched grooves and a third groove interposed between said switched grooves, means communicating said third groove with the low hydraulic pressure manifold, a pair of grooves in said spaced end surfaces each communicating with one of said switched grooves and extending radially inwardly with the ends thereof circumferentially spaced.

Claim 3

In a hydraulic device including a housing, a cavity in the housing defined by parallel spaced end surfaces and a cylindrical bearing surface, inlet and outlet ports in the housing communicating with the cavity, one of said ports adapted to be at high hydraulic pressure and the other said ports adapted to be at low hydraulic pressure, a rotatable shaft extending into the cavity and having an axis spaced from the axis of said bearing surface, a member secured to such shaft for rotation therewith and having alternate teeth and root portions therebetween on the outer periphery, a cylindrical ring member rotatably supported in said bearing surface and having on the inner surface thereof a plurality of alternate teeth and root portions, the teeth and root portions of said members cooperating to define increasing and decreasing volume chambers therebetween as the members rotate, said bearing surface and said cylindrical member cooperating to define a bearing clearance therebetween, said hydraulic device having a neutral axis defined by a line drawn through the points of maximum and minimum volume of said chambers, at least some of said chambers on one side of said axis being at high hydraulic pressure and at least some of said chambers on other side of said neutral axis being at low hydraulic pressure, the chamber at maximum volume being a switch chamber which is alteRnately communicated with the inlet and outlet ports of the device and thus to high and low hydraulic pressures, the improvement which comprises means permanently communicating high hydraulic pressure to the bearing clearance on the high pressure side of the neutral axis, at least one fixed point on said bearing surface adapted to be communicated with a low pressure port and means alternately communicating said point with said low pressure port and cutting it off from said port as said cylindrical member rotates.

Claim 4

In a hydraulic device including a housing, a cavity in the housing defined by parallel spaced end surfaces and a cylindrical bearing surface, inlet and outlet ports in the housing communicating with the cavity, one of said ports adapted to be at high hydraulic pressure and the other said ports adapted to be at low hydraulic pressure, a rotatable shaft extending into the cavity and having an axis spaced from the axis of said bearing surface, a member secured to such shaft for rotation therewith and having alternate teeth and root portions therebetween on the outer periphery, a cylindrical ring member rotatably supported in said bearing surface and having on the inner surface thereof a plurality of alternate teeth and root portions, the teeth and root portions of said members cooperating to define increasing and decreasing volume chambers therebetween as the members rotate, said bearing surface and said cylindrical member cooperating to define a bearing clearance therebetween, said hydraulic device having a neutral axis defined by a line drawn through the points of maximum and minimum volume of said chambers, at least some of said chambers on one side of said axis being at high hydraulic pressure and at least some of said chambers on other side of said neutral axis being at low hydraulic pressure, the chamber at maximum volume being a switch chamber which is alteRnately communicated with the inlet and outlet ports of the device and thus to high and low hydraulic pressures, the improvement which comprises means permanently communicating high hydraulic pressure to the bearing clearance on the high pressure side of the neutral axis, at least one fixed point on said bearing surface adapted to be communicated with a low pressure port and means alternately communicating said point with said low pressure port and cutting it off from said port as said cylindrical member rotates.

Claim 5

The improvement of claim 2 wherein said point is a switched groove in said bearing surface.

Claim 6

The improvement of claim 2 wherein said alternately communicating means is a groove in at least one of said parallel cavity surfaces extending radially inwardly a distance just beyond the root diameter of said cylindrical member so as to be communicated with and cut off from said chambers as said member rotates.

Claim 7

The improvement of claim 2 wherein said high hydraulic pressure means includes two grooves in said cylindrical bearing surface each adjacent an end of said neutral axis and means permanently communicating said grooves with said high pressure manifold.

Claim 8

The improvement of claim 2 wherein there are two such points in said bearing surface and means alternately communicating said points with and cutting said points off from the low pressure port as said cylindrical member rotates.

Claim 9

The improvement of claim 6 wherein a third point in said bearing surface is positioned between said pair of points and means permanently communicate said third point to said low pressure port.

Claim 10

The improvement of claim 6 wherein said alternately communicating means comprise a pair of grooves in at least one of said parallel surfaces extending radially inwardly a distance just beyond the root diameter of said ring gear such as to alternately communicate with and be sealed off from the low pressure chambers as said cylindrical member rotates, the inner ends of said grooves being spaced circumferentially a distance such that only one groove is in communication with a chamber at a time.

Claim 11

The improvement of claim 6 wherein a pair of grooves in at least one of the cavity parallel surfaces extend radially inwardly from said fixed points a distance just beyond the root diameter of said cylindrical member such as to alternately communicate with and be sealed off from said chambers as said cylindrical member rotates, the inner ends of said grooves being spaced circumferentially such that only one groove is in communication with a chamber at a time.

Claim 12

The improvement of claim 6 wherein said spaced points on said bearing surface are axially extending grooves in said cylindrical bearing surface.

Claim 13

The improvement of claim 6 wherein a pair of fixed points are provided on said bearing surface on both sides of said neutral axis adapted to be periodically communicated with the chambers on their respective side of said neutral axis and means alternately communicating each point with said chambers as said members rotate.

Claim 14

In a hydraulic device including a housing, a cavity in the housing defined by parallel spaced end surfaces and a cylindrical bearing surface, inlet and outlet ports in the housing communicating with the cavity, one of said ports adapted to be at high hydraulic pressure and the other said ports adapted to be at low hydraulic pressure, a rotatable shaft extending into the cavity and having an axis spaced from the axis of said bearing surface, a member secured to such shaft for rotation therewith and having alternate teeth and root portions therebetween on the outer periphery, a cylindrical ring member rotatably supported in said bearing surface and having on the inner surface thereof a plurality of alternate teeth and root portions, the teeth and root portions of said members cooperating to define increasing and decreasing volume chambers therebetween as the members rotate, said bearing surface and said cylindrical member cooperating to define a beariNg clearance therebetween, said hydraulic device having a neutral axis defined by a line drawn through the points of maximum and minimum volume of said chambers, at least some of said chambers on one side of said axis being at high hydraulic pressure and at least some of said chambers on other side of said neutral axis being at low hydraulic pressure, the chamber at maximum volume being a switch chamber which is alternately communicated with the inlet and outlet ports of the device and thus to high and low hydraulic pressures, the improvement which comprises means permanently communicating high hydraulic pressure to the bearing clearance on the high pressure side of said neutral axis, a point in said bearing surface communicating with said bearing clearance said point located on the side of the neutral axis remote from high pressure and adjacent a switching chamber at open mesh, means alternately communicating said point with a second chamber at high pressure and cutting it off from said second chamber as said cylindrical member rotates.

Claim 15

In a hydraulic device including a housing, a cavity in the housing defined by parallel spaced end surfaces and a cylindrical bearing surface, inlet and outlet ports in the housing communicating with the cavity, one of said ports adapted to be at high hydraulic pressure and the other said ports adapted to be at low hydraulic pressure, a rotatable shaft extending into the cavity and having an axis spaced from the axis of said bearing surface, a member secured to such shaft for rotation therewith and having alternate teeth and root portions therebetween on the outer periphery, a cylindrical ring member rotatably supported in said bearing surface and having on the inner surface thereof a plurality of alternate teeth and root portions, the teeth and root portions of said members cooperating to define increasing and decreasing volume chambers therebetween as the members rotate, said bearing surface and said cylindrical member cooperating to define a beariNg clearance therebetween, said hydraulic device having a neutral axis defined by a line drawn through the points of maximum and minimum volume of said chambers, at least some of said chambers on one side of said axis being at high hydraulic pressure and at least some of said chambers on other side of said neutral axis being at low hydraulic pressure, the chamber at maximum volume being a switch chamber which is alternately communicated with the inlet and outlet ports of the device and thus to high and low hydraulic pressures, the improvement which comprises means permanently communicating high hydraulic pressure to the bearing clearance on the high pressure side of said neutral axis, a point in said bearing surface communicating with said bearing clearance said point located on the side of the neutral axis remote from high pressure and adjacent a switching chamber at open mesh, means alternately communicating said point with a second chamber at high pressure and cutting it off from said second chamber as said cylindrical member rotates.

Claim 16

The improvement of claim 12 wherein said communicating means comprises an arcuate groove in one of said spaced end surfaces extending from said point radially inwardly a distance just beyond the root diameter of said cylindrical member so as to be communicated with and cut off from said chambers as said member rotates.