US3760690A - Rotary hydraulic machines - Google Patents

Abstract

A rotary hydraulic machine has a rotor journalled on a pintle which extends internally of the machine casing. The rotor has an axial bore into which the pintle extends so as to provide a space between the end of the pintle and the end of the bore. Fluid pressure within the casing is admitted to this space to partially offset the pressure urging the rotor onto the pintle.

Description

United States Patent Freeman Sept. 25, 1973 [54] ROTARY HYDRAULIC MACHINES 3,283,668 11/1966 Louhio 91/44 4 [75] Inventor: Frank George Freeman, Solihull, 3O78808 2/1963 Byers 91 England Primary ExaminerWilliam L. Freeh [73] Assignee. Joseph Lucos (Industries) Limited, Asst-slam Examiner cregory P. La Poime Blrmmgham England Attorney-Holman & Stern [22] Filed: June 28, 1971 Appl. No.: 157,386

US. Cl. 91/484, 91/491 Int. Cl. F04b 19/00 Field of Search 9l/484, 485, 486,

References Cited UNITED STATES PATENTS 2/194l Ferris 91/484 [57] ABSTRACT 4 Claims, 3 Drawing Figures Pmmmsmsma 3.760.690

' sum 1 or 2 I FIGZ.

PATENTED 3.760.690 v SHEEI 2 OF 2 INVENT R kZM%M Z Mm ROTARY HYDRAULIC MACHINES This invention relates to rotary hydraulic machines and has as an object the provision of such a machine in a convenient form.

According to the invention a rotary hydraulic 'machine comprises a casing, a pintle extending into the casing, a rotor mounted on the pintle, the said rotor having an axial bore into which the pintle extends so as to define a space between the end of the pintle and the end of the bore, an annular part disposed eccentrically of the rotor, a plurality of pistons slidable in radial bores in the rotor and engaging an inner surface of the annular part and a passage in the rotor whereby a fluid pressure within the casing is admitted to the said space between the axial bore and pintle, the arrangement being such that the sum of the axial forces on the rotor has a desired value and acts in a direction to urge the rotor on to the pintle.

A hydraulic motor according to the invention will now be described by way of example and with reference to the accompanying drawings in which:

FIG. 1 is a section through a motor,

FIG. 2 is a section of line 2-2 in FIG.'1; and

FIG. 3 is a scrap view, to a different scale, of a part of FIG. 1.

The motor has a casing formed in two parts 10, 11. Part has an integral pintle 12 within which are passages 13, 14 which communicate'with respect ports 15, 16 opening on to the surface of the pintle l2. Passages l3, 14 also communicate respectively with an inlet (not shown) and an outlet 17 for the motor. A rotor mounted on the pintle 12 includes a cylinder member 18 and a shaft 19 secured to the member 18 by a stepped flange 19a.

The dimensions of the member 18 and pintle l2.are such as to define an annular space 20, shown more clearly in FIG. 3, between the end of the pintle l2 and the flange 19a of the shaft 19. The flange 19a is engaged on opposite sides by a pair of bearing seal rings 21,22 each having a low co-efficient of friction. Rings 21, 22 are carried by bushes 23, 24 respectively sealingly and slidably engaged in an end wall of the body part 11 and in the pintle 12. Spring washers 25, 26 act to urge the bushes 23, 24 respectively towards the flange 19a, and hence the associated rings 21, 22 into close engagement with the flange 19a. A passage 27 in the cylinder member 18 allows the annular space to communicate with the interior of the casing 10, 11.

The cylinder member 18 is formed with two rows of stepped radial bores 28, a piston 29 being slidable in each bore 28. Each piston 29 has a slipper 30 secured thereto by a hollow rivet 31. The casing part 11 is formed internally with a pair of part-spherical surfaces 11a disposed eccentricallywith respect to the cylinder member 18. Slippers engage the surfaces 11a.

In use, hydraulic fluid under pressure is supplied via the inlet and passage 15 .to operate the motor in a known manner, and is subsequently discharged via passage 16 and outlet 17. Fluid at a high pressure is also admitted to the interior of the casing via an orifice not shown) opening into the motor inlet. This fluid pressure acts on the end faces of the cylinder member 18, the difference in the areas of the end faces resulting in a force tending to urge the rotor to the right, as shown in FIG. 1. The same fluid pressure enters the space 20 via passage 27 and acts upon flange 19a, tending to urge the rotor to the left. The resultant force on the rotor is thus reduced, though still tending to urge the rotor to the right. The resultant force may, by themrangement described, be maintained at a desired value without the necessity of making the shaft 19 an unacceptably large diameter. Fluid leaking into the bore of bush 24 escapes to low pressure via an axial passage 32 in shaft 19.

it will be understood that an arrangement substantially as described above may also be used as a pump, in which case a liquid is drawn in via port 16 and discharged under pressure through port 15'.

I claim:

1. A rotary hydraulic machine comprising a pressure fluid containing casing, a ported pintle extending into the casing, a rotor mounted on the pintle and comprising a cylinder member and a flanged shaft secured thereto said cylinder member, having an axial bore into which the pintle extends, a part extending axially from the end of the pintle and sealingly engaged with the flange of said shaft so as to define a closed annular space between the end of the pintle and said flange, an annular part disposed excentrically of the rotor, a plurality of pistons slidable in radial bores in the cylinder member and engaging an inner surface of said annular part and a passage in the cylinder member whereby the fluid pressure contained within the casing is admitted to said closed annular space, whereby a force caused in use by a fluid pressure acting on the rotor to urge the rotor on to the pintle is partially offset by an opposing force on the rotor caused by fluid pressure acting in said closed annular space.

2. A machine as claimed in claim 1 in which said axially extending part comprises a bush sealingly slidable within said end of the pintle and there is provided means for biasing said bush towards said end of the axial bore 3. A machine as claimed in claim 2 which includes a sealing ring carried by said bush and engaging said end of the axial bore.

4. A machine as claimed in claim 3 in which said sealing ring has a low coefficient of friction.

Claims (4)

1. A rotary hydraulic machine comprising a pressure fluid containing casing, a ported pintle extending into the casing, a rotor mounted on the pintle and comprising a cylinder member and a flanged shaft secured thereto said cylinder member, having an axial bore into which the pintle extends, a part extending axially from the end of the pintle and sealingly engaged with the flange of said shaft so as to define a closed annular space between the end of the pintle and said flange, an annular part disposed excentrically of the rotor, a plurality of pistons slidable in radial bores in the cylinder member and engaging an inner surface of said annular part and a passage in the cylinder member whereby the fluid pressure contained within the casing is admitted to said closed annular space, whereby a force caused in use by a fluid pressure acting on the rotor to urge the rotor on to the pintle is partially offset by an opposing force on the rotor caused by fluid pressure acting in said closed annular space.

2. A machine as claimed in claim 1 in which said axially extending part comprises a bush sealingly slidable within said end of the pintle and there is provided means for biasing said bush towards said end of the axial bore

3. A machine as claimed in claim 2 which includes a sealing ring carried by said bush and engaging said end of the axial bore.

4. A machine as claimed in claim 3 in which said sealing ring has a low coefficient of friction.

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