US3884124A

US3884124A - Hydraulic device

Info

Publication number: US3884124A
Application number: US352424A
Authority: US
Inventors: Robert T Eddy
Original assignee: Reliance Electric Co
Current assignee: Reliance Electric Co
Priority date: 1973-04-19
Filing date: 1973-04-19
Publication date: 1975-05-20
Anticipated expiration: 1992-05-20
Also published as: BE811840A; DE2409119A1; JPS50249A; FR2226570A1; FR2226570B1; IT1009911B; AU6530474A; GB1424993A; CA1008301A

Abstract

A hydraulic motor having a stator with alternately inwardly and outwardly, radially extending reaction surfaces, a rotor disposed within said stator and having a plurality of chambers in its peripheral surface elongated in the direction of the axis of the rotor, and slippers disposed in each of the chambers for reciprocating movement therein. Each slipper has a recess in the surface facing the reaction surfaces, and a rolling element disposed in each recess contacts the reaction surface. Relative movement between the stator and rotor causes a tilting action of the slipper which is utilized to form a contact seal between the side of the slipper and the side walls of the chambers. Lubricating channels may be provided in the surface of the recess to lubricate the rolling element, utilizing the hydraulic fluid communicated to the channels by passages in the slipper. While the hydraulic device is intended primarily for use as a motor, the principles involved in the motor may be utilized effectively in a pump.

Description

United States Patent 1191 Eddy 14 1 May 20, 1975 HYDRAULIC DEVICE Robert T. Eddy, South Bend, Ind.

[73] Assignee: Reliance Electric Company,

Mishawaka, Ind.

[22] Filed: Apr. 19, 1973 [21] Appl. No.: 352,424

[75] Inventor:

2,292,181 4/1942 Tucker..... 91/488 2,459,786 1/1949 Beaman i I 91/499 2,612,110 9/1952 Delegard 417/204 2,712,794 7/1955 Humphreys..... 91/472 3,046,950 7/1962 Smith 91/498 3,699,848 10/1972 Prendergast.... 91/487 3,724,334 4/1973 Denker 91/491 FOREIGN PATENTS OR APPLICATIONS 679,768 2/1964 Canada 1. 417/204 1,133,388 11/1956 France 92/172 Primary Examiner-William L. Freeh Attorney, Agent, or FirmMarmaduke Hobbs Hobbs & Green 1 71 ABSTRACT A hydraulic motor having a stator with alternately inwardly and outwardly, radially extending reaction surfaces, a rotor disposed within said stator and having a plurality of chambers in its peripheral surface elongated in the direction of the axis of the rotor, and slippers disposed in each of the chambers for reciprocating movement therein. Each slipper has a recess in the surface facing the reaction surfaces, and a rolling element disposed in each recess contacts the reaction surface. Relative movement between the stator and rotor causes a tilting action of the slipper which is utilized to form a Contact seal between the side of theslipper and the side walls of the chambers. Lubricating channels may be provided in the surface of the recess to lubricate the rolling element, utilizing the hydraulic fluid communicated to the channels by passages in the slipper. While the hydraulic device is intended primarily for use as a motor, the principles involved in the motor may be utilized effectively in a pump.

13 Claims, 8 Drawing Figures HYDRAULIC DEVICE In hydraulic systems, conventional vane and gear type hydraulic motors and gcrotor motors are extensively used and will perform satisfactorily under normal operating conditions, and will have a reasonably long operating life at low and moderate hydraulic pressures. However, at relatively high pressures these motors fre quently have only a limited life, and their efficiency is often impaired within a relatively short time at the higher pressures. The parts of these conventional motors often are subjected to excessive wear at normal pressures, and in order to obtain the required operating efficiency, relatively close tolerances must be maintained in fabricating the motor parts. Further, under certain conditions of operation. such as when the motor is being driven by the equipment, normally driven by the motor, cavitation may occur in the hydraulic system anterior to the motor which may place an undue burden on the equipment and system or render the system inoperative. It is therefore one of the principal objects of the present invention to provide a hydraulic motor which can be operated efficiently under high pressure and at high torque for extended periods of time without failure, and which is so constructed and designed that the parts thereof have a long life throughout the normal pressure operating range.

Another object of the invention is to provide a motor having a plurality of reaction elements, which will not become pumping elements in the event the equipment, normally driven by the motor, drives the motor, and which hence will not cause cavitation in the hydraulic lines of the system, but rather becomes free wheeling whenever the foregoing condition develops in the motor-equipment installation, thus minimizing the braking action of the motor during such operating conditions.

Still another object is to provide a relatively simple, compact and versatile hydraulic motor having a series of reciprocating elements forming a pressure responsive means in individual chambers, which have a slipper-type wear compensating and fluid sealing structure, for increasing the operating efficiency and extending the effective life of the elements, and which is easily serviced and repaired to maintain the motor in optimum operating condition.

A further object is to provide a motor of the aforementioned type having a stator and a rotor in which the rotor and the output shaft therefor are hydraulically balanced.

Additional objects and advantages of the invention will become apparent from the following description and accompanying drawings, wherein:

FIG. 1 is an elevational view of the present hydraulic motor;

FIG. 2 is an enlarged crosssectional view of the hydraulic motor shown in FIG. 1, the section being taken on line 2 2 of the latter figure;

FIG. 3 is a transverse cross-sectional view of the hy draulic motor shown in the preceding figures, the section being taken on line 3 3 of FIG. 2;

FIG. 4 is a cross-sectional view of the hydraulic motor, the section being taken on line 4 4 of FIG. 2;

FIG. 5 is a fragmentary cross-sectional view of the rotor, the section being taken on line 5 5 of FIG. 4;

FIG. 6 is an enlarged diagrammatical view of one of the cylinders of the motor, illustrating the operation of the piston and slipper type seal incorporated therein;

FIG. 7 is an enlarged detail view ofa slightly modified form of the slipper used in the device shown in the preceding figures; and

FIG. 8 is a side elevational view of the slipper shown in FIG. 7.

Referring more specifically to the drawings, numeral 10 indicates generally the present hydraulic motor having fluid inlet passage 12, fluid outlet passage 14, and power output shaft 16. While the description is directed to the present device as a hydraulic motor, it may be used as a hydraulic pump if desired with few or no changes in the basic structure thereof; however, the description hereinwill be directed primarily to the use of the device as a hydraulic motor. The system in which the motor is used normally includes a hydraulic pump for providing the necessary hydraulic pressure through a line from the pump to inlet 12 and a return line connected to outlet 14. The system, including the motor and the pump which is normally driven by an electrical motor or an engine, may be used to drive a variety of different types of machines or equipment, connected to shaft 16 of the hydraulic motor.

The motor 10 consists of a rotor 20 having a plurality of fluid chambers 22 and rolling elements 24 in the fluid chambers operating in effect as pistons. The rotor is mounted on output shaft 16 and secured thereto by key 26 disposed in key-

ways

28 and 30 in the rotor and shaft, respectively. The rotor is disposed in a stationary stator 40 or reaction member, the external part of which forms the periphery of housing 42 which includes

end sections

44 and 46 and intermediate section or port ring 48. The four

sections

40, 44, 46 and 48 are secured together to form a rigid housing structure by a plurality of bolts 50 extending through holes in the sections and being threadedly received in holes 52 in section 44, and the sections are preferably sealed by gaskets such as O-rings 49. Shaft 16 is journaled in

bearings

54 and 56 disposed in annular recesses in the internal face of

sections

44 and 46, the shaft being sealed by an annular seal 58 in the enlarged opening 60 through the end section 44 in which the shaft rotates. The shaft is held against end-wise axial movement by a collar 62 engaging bearing 54 and shoulder 64 engaging bearing 56, and the outer end of shaft 16 is provided with a key and key-way in order to connect the shaft to the driven mechanism or equipment. A sheave, gear, or other drive transmission element may be mounted on the shaft, or the shaft may be coupled directly to the input shaft of the driven equipment.

The chambers 22 in rotor 20 consist of slots extendlng across the periphery of the rotor, and the rolling elements 24 are adapted to reciprocate therein from the internal end of the chamber, as viewed in the one at the top of FIG. 4, to their fully extended position as illustrated by the two cylinders in approximately the 4 and 8 oclock positions as viewed in FIG. 4. The rolling elements are forced outwardly by the pressure in the chambers on the internal side of the elements 24 and the elements react against the increasing surfaces of each lobe 72 on the cam surface of reaction member 40. When the pressure is relieved in chambers 22, the fluid is ejected therefrom through outlet 14 at a relatlvely low pressure, as the rolling elements 24 engage decreasing cam surfaces 74. The number of lobes 72 on the cam surface is different from the number of chambers and rolling elements, either greater or fewer in number, in order to maintain a uniform operation in the device. The rolling elements 24 are cylindrical in shape and are substantially the same length as the width of rotor and form a relatively snug fit at the ends between

sections

44 and 48, as seen in FIG. 2, thus eliminating or minimizing the flow of fluid from the inner end of chambers 22 to the space 80 between lobes 72, although some fluid may seep into the spaces 80, and a drain is provided therefor. The spaces are connected to one another by an annular passage 81 in the inner face of section 44. The fluid finding its way into space 80 is removed by a drain passage 82 extending inwardly to a transverse passage 84 adjacent shaft 16. This transverse passage communicates with a drain cavity 86 which is in turn drained by a conduit (not shown) connected to cavity 86 through threaded hole 88. Thus the fluid is not permitted to build up a back pressure in the spaces 80, which might otherwise react against the rolling elements and interfere with the proper operation of the motor.

Chambers 22 are alternately connected to the high pressure inlet 12 and low pressure outlet 14 by

ports

90 and 92 in port plate or section 48, the ports 90 being connected by an annular groove 96 in section 46 with inlet port 12, and ports 92 being connected by annular groove 94 in section 46 with outlet port 14. When chambers 22 are communicating with ports 90, the rolling elements 24 are traversing outwardly extending inclines 70 of the cam surface on the stator, and when the chambers are in communication with ports 92, the rolling elements are traversing inwardly extending surfaces 74. The rolling elements are urged outwardly by the high pressure transmitted to the chamber from conduit 12 and ports 90, against the inclined surfaces 70, thus 1 causing rotational movement of rotor 20. The inwardly inclined portions 74 return the rolling elements to the inner ends of chambers 22, causing the fluid in the chambers to be ejected through ports 92 and low pressure outlet 14. The rotor is hydraulically balanced by the transmittal of hydraulic fluid to the side of the rotor 20

opposite ports

90 and 92. These ports are connected by a passage 100 extending completely through the rotor to slots 102 which are shown as located in the surface of section 44, but which may be located in the respective side of the rotor. Passage 100 transmits the pressure of either ports 90 or ports 92 to the opposite side of the rotor, and since slots 102 communicate with passage 100, the pressure of the fluid received from passage 100 is applied to the left hand side of the rotor as viewed in FIG. 2, i.e. to the side opposite the side on which the

ports

90 and 92 are located. The slots 102 are positioned with respect to

ports

90 and 92 in such a way as to vary the pressure in response to the varying communication of chambers 22 with one or the other of

ports

90 or 92. Thus each of the slots 102 contains fluid under a pressure representing the pressure being applied at the particular moment on the opposite side of the rotor.

Rolling elements 24 are mounted in slippers 110 which in turn are mounted in chambers 22. The primary advantage of the combination rolling element and slipper is the ability of the slipper to maintain an effective seal between the side walls in the rotor defining chambers 22. The slipper is so constructed that an effective sealing contact is maintained by the pressure applied on the rolling elements as the rolling elements reciprocate inwardly and outwardly in engagement with the undulating cam surface. In a motor, as rotor 20 rotates in the clockwise direction and as the rolling element contacts surface 74, the slipper tends to rotate angularly in the counter clockwise direction, as viewed in FIG. 4, thus applying additional pressure at points or edges 112 and 114 on the side walls of chamber 22. As seen in FIG. 6, decreasing cam surface 74 causes the slipper to rotate in clockwise direction, hence causes points or edges 116 and 118 to be pressed into firm and sealing engagement with the transverse side walls of the chambers. Thus an effective seal is maintained throughout the length of the slippers, regardless of whether the rolling elements are driving the rotor or are being driven by the cam surface to expel the low pressure fluid in the chamber. This operation takes place effectively notwithstanding any normal wear which may occur either in the side walls of the slipper or in the side walls of the rotor defining chambers 22, in that any wear occurring in either the side walls of the chambers or in the sides of the slipper is compensated for by further tilting or rotation of the slipper against or into the two opposed, straight side walls defining the champer.

In the slipper form illustrated in FIGS. 7 and 8 and identified by numeral 110, lubricating grooves are provided so that the hydraulic fluid can effectively lubricate the cylindrical piston disposed in bearing recess 120. The system for lubricating the roller includes two

longitudinal grooves

122 and 124 spaced laterally from the center of bearing recess 120, and

grooves

126 and 128 in opposite ends of the slipper communicating with the ends of

grooves

122 and 124, respectively. Hydraulic fluid is thus permitted to flow from chamber 22 through

grooves

126 and 128 at each end of slipper into

grooves

122 and 124 where it effectively forms a film on the inner surface of recess between the slipper walls and the rotating cylindrical element 24. In order to assure effective lubrication between the sides of the slipper and the straight, parallel sides of the chamber walls, a plurality of grooves 130 are provided on the sides of the slipper. While these grooves 130 assist in maintaining effective lubrication between the slipper walls of the chamber, they also assist in minimizing leakage which might tend to occur between the walls of the two slippers and cylinders as the slippers tilt or shift from one sealing position to another.

In the operation of the present motor, with the motor being connected to a mechanism or other equipment to be driven thereby, the fluid is transmitted from a high pressure source to inlet 12. The high pressure fluid then passes through annular groove 96 and ports 90 into the chambers which are in communication with ports 90. These chambers contain the rolling elements in contact with the outwardly extending inclined portions 70 of the cam surface of the stator. The high pressure forcing the rolling elements outwardly causes the rotor to rotate in the clockwise direction, as viewed in FIG. 4. The chambers containing the rolling elements in contact with the inwardly extending inclined surfaces 74 are in communication with the ports 92, which in turn are in communication with groove 94 and outlet port 14. The movement of the rolling elements inwardly on inclined surfaces 74 ejects the low pressure fluid from chambers 22. As pointed out previously herein, in this embodiment, fewer chambers 22 and rolling elements 24 are provided in the rotor than lobes 72 on the stator, so that there is a constant and uniform rotational movement of the rotor with substantially constant pressure being applied at spaced points around the periphery thereof as the rolling elements react on inclined surfaces 70. As the rotor rotates, the pressure on opposite sides of the rotor is maintained substantially equal in the manner previously described herein, by the fluid transmitted through passage 100 to the slots 102. Thus the rotor is hydraulically balanced on all principal axes.

While only one embodiment has been described in detail herein, various changes and modifications may be made without departing from the scope of the invention.

I claim:

1. A hydraulic device comprising a stator means, a rotor means, one of said means having a plurality of alternate outwardly and inwardly, radially extending reaction surfaces and the other of said means having a plurality of fluid chambers with an opening facing said reaction surfaces, a slipper disposed in each of said chambers for reciprocating movement therein and having a recess in the surface facing said reaction surfaces, a rolling element disposed in said recess and contacting said reaction surfaces, each of said slippers being tiltable to both sides of the radial center line of the respective roller by the motion between the stator and rotor means to form a contact seal with both side walls of its chamber, the side walls of said slippers having a curvature which increases the sealing contact pressure as the slipper tips further from the radial center line of the respective chamber, and fluid inlet and outlet ports bein alternately connected with said chambers.

2. A hydraulic device as defined in claim 1 in which said stator means is annular shaped and contains the outwardly and inwardly extending reaction surfaces, and said rotor means is disposed within said stator means, and said fluid chambers are disposed in said rotor means in the periphery thereof.

3. A hydraulic device as defined in claim 1 in which said chambers are elongated in the axial direction of said rotor means and extend to the opposite edges of said means.

4. A hydraulic device as defined in claim 2 in which said chambers are elongated in the axial direction of said rotor means and extend to the opposite edges of said means.

5. A hydraulic device as defined in claim 3 in which said slippers are substantially the same length as said chambers and said rolling elements are cylindrically shaped and substantially the same length as said chambers.

6. A hydraulic device as defined in claim 4 in which said slippers are substantially the same length as said chambers and said rolling elements are cylindrically shaped and substantially the same length as said chambers.

7. In a hydraulic device having a stator means, a rotor means, one of said means having a plurality of alternate outwardly and inwardly, radially extending reaction surfaces and the other of said means having a plurality of fluid chambers with an opening facing said reaction surfaces, said chambers being elongated in the axial direction of said rotor means: a slipper element for said chambers having an elongated body of substantially the same axial length as the cylinders and elongated recess extending in the axial direction disposed in the surface of said element and facing said reaction surfaces for receiving a rolling element, said slipper element being tiltable to both sides of the radial center line of the respective roller by the relative motion between said stator and rotor means to form a contact seal with both side walls of the chamber, the side walls of said slippers having a curvature which increases the sealing contact pressure as the slipper tips further from the radial center line of the respective chamber.

8. A slipper element as defined in claim 7 in which longitudinal grooves are provided in the side wall of said recess and a passage connects each of said grooves with the respective fluid chamber for lubricating the rolling element.

9. A slipper element as defined in claim 7 in which a longitudinal groove is disposed on opposite sides of the external surface of said slipper.

10. A hydraulic device as defined in claim 7 in which the chambers are in the rotor means, and said slipper element applies a fluid sealing force to the walls of said rotor means defining the respective chamber as the rolling element supported by said slipper element engages said alternately outward and inward reaction surfaces.

11. A hydraulic device as defined in claim 10 in which the walls defining said chamber in said rotor means extend axially from one side of the rotor means to the other and are straight and parallel to one another in the area engaged by said slipper element.

12. A hydraulic device as defined in claim 11 in which opposite sides of said slipper element firmly contact opposite walls of the respective chamber when said slipper elements are tilted by the relative movement of the rotor means in the stator means.

13. A hydraulic device as defined in claim 12 in which opposite sides of said slipper element contact opposite walls of the respective chamber when said slipper elements are tilted by the relative movement of the rotor means in the stator means, with the margins of the longitudinal side edges of the slipper element forming the line of contact between the slipper element and the sides of the respective chambers.

Claims

1. A hydraulic device comprising a stator means, a rotor means, one of said means having a plurality of alternate outwardly and inwardly, radially extending reaction surfaces and the other of said means having a plurality of fluid chambers with an opening facing said reaction surfaces, a slipper disposed in each of said chambers for reciprocating movement therein and having a recess in the surface facing said reaction surfaces, a rolling element disposed in said recess and contacting said reaction surfaces, each of said slippers being tiltable to both sides of the radial center line of the respective roller by the motion between the stator and rotor means to form a contact seal with both side walls of its chamber, the side walls of said slippers having a curvature which increases the sealing contact pressure as the slipper tips further from the radial center line of the respective chamber, and fluid inlet and outlet ports being alternately connected with said chambers.