US3228304A

US3228304A - Hydraulic distribution valves

Info

Publication number: US3228304A
Application number: US275694A
Authority: US
Inventors: Sherwen Theo
Original assignee: Prime Movers Wiltshire Ltd
Current assignee: Prime Movers Wiltshire Ltd
Priority date: 1962-05-04
Filing date: 1963-04-25
Publication date: 1966-01-11
Anticipated expiration: 1983-01-11
Also published as: GB970258A

Description

Jan. 11, 1966 T. SHERWEN 3,228,304

HYDRAULI C DI STRIBUTION VALVES Filed April 25, 1963 3 Sheets-Sheet 1 Jan. 11, 1966 Filed April 25, 1963 T. SHERWEN HYDRAULIC DISTRIBUTION VALVES 5 Sheets-Sheet 2 Jan. 11, 1966 T. SHERWEN 3,228,304

HYDRAULIC DISTRIBUTION VALVES Filed April 25, 1963 3 SheetsSheet :5

United States Patent 3,228,304 HYDRAULIC DISTREBUTEUN VALVES Theo Sherwen, Yew lorch, Minchinhanipton, Gloucestershire, England, assignor to Prime Movers (Wiltsh re) Limited, Yew Porch, Minehinhampton, Gloucestershire, England, a British company Filed Apr. 25, 1963, Ser. No. 275,6?4 Claims priority, application Great Britain May 4, 1962, 17,268/ 62 Claims. (Cl. 91204) This invention relates to hydraulic distribution valves for sequentially connecting pressure and exhaust ports in a stator with flow and return ports in a co-operating rotor, and is mainly concerned with simplifying the construction of such valves.

Accordingly, the invention provides a hydraulic distribution valve including a stator block having pressure and exhaust ports opening therethrough in-to opposed arcuate recesses in one block face, a rotor arranged for rotatable mounting relative to the stator with one face overlying the recessed face of said stator block and having ports therethrough with openings in said overlying face positioned to register alternately with said stator recesses during relative rotation of the rotor, and sealing means interposed between said overlying stator and rotor faces to provide substantially sealed connections between the respective stator recesses and the rotor ports.

Such a valve is particularly, though not exclusively, suitable for use in a vehicle wheel driven by a hydraulic motor built-in to the wheel hub. Accordingly, the invention further provides, in a vehicle wheel having a hub with a built-in hydraulic multi-cylinder driving motor mounted for rotation on a relatively non-rotary cam shaft, a hydraulic distribution valve including a stator block which is secured to the outer end of said cam shaft and has pressure and exhaust ports connecting with pressure and exhaust passages formed through the cam shaft and opening into opposed arcuate recesses in an outer block face, a rotor mounted on said wheel hub with one ported face overlying the recessed face of said stator block, the ports in said overlying rotor face being positioned to register alternately with said stator recesses during rotation of the rotor and being connected with flow and return passages leading to the respective cylinders of the motor, and sealing means interposed between said overlying stator and rotor faces to provide substantially sealed connections between the respective stator recesses and the rotor ports.

In order that the invention may be clearly understood and readily carried into effect, two embodiments thereof will now be described in detail with reference to the accompanying drawings, in which:

FIGURE 1 is a side elevational view showing the hub of a vehicle wheel having a built-in hydraulic motor supplied with fluid through a hydraulic distribution valve of the invention,

FIGURE 2 is an outline side view of the wheel hub shown in FIGURE 1 with part of the distribution valve and part of a cam shaft, on which the hub is mounted, shown in cross-section,

FIGURE 3 is a sectional view, to an enlarged scale and partially broken away, showing details of the hydratilic distribution valve embodied in FIGURES 1 and 2,

FIGURE 4 is a sectional view of the valve stator block taken'on the line IV-IV of FIGURE 3,

FIGURE 5 is a further sectional view of the stator block taken on the line VV of FIGURE 4,

FIGURE 6 is a side elevational view showing part of a slightly modified vehicle wheel hub fitted with an alternative form of hydraulic distribution valve in accordance with the invention,

FIGURE 7 is a cross-sectional view corresponding to FIGURE 6, and

FIGURES 8, 9 and 10 show respectively a top view, a side view and a front view of the stator block employed in the hydraulic distribution valve embodied in FIG- URES 6 and 7.

In the drawings, FIGURES l to 5 show a hydraulic distribution valve for use on the hub of a road or ground wheel of a vehicle having a built-in hydraulic motor. To accommodate the motor, the wheel has a rotary hub casing 1 which is intended to carry the wheel rim (not shown) and is mounted on a non-rotary or relatively stationary cam shaft 2 on the vehicle in generally known manner. In this example, the hydraulic motor has five radial cylinders 3, provided around the Wheel hub at equally spaced intervals, in which hydraulic pistons (not shown) work in co-operation with the cam periphery on the cam shaft, again in generally known manner.

To provide for the flow and return of hydraulic pressure fluid to the aforesaid hub cylinders 3, supply and exhaust passages 4 and 5 are provided axially through the cam shaft 2 and open into the outer cam shaft end. These passages are then connected through the distribution valve with radial flow and return passages 6 carried by the wheel hub and leading to the respective cylinders 3.

The distribution valve is constituted, in this em'bodiment, by a stator block 7 which is of circular plate-like form and is concentrically attached to the outer end of the cam shaft 2 by means of a screw 8 or the like. This stator block may be made of any appropriate material having the requisite strength, one suitable material being that sold under the trade name Mazak. The block has ports 9 therethrough which are displaced by 180 from one another and which extend from circular openings in the rear block face, these openings being respectively registered with the pressure and exhaust passages 4 and 5 through the cam shaft. To prevent or inhibit leakage, flexible sealing rings (not shown), may be provided at the junctions of the passage openings in the cam shaft end and the port openings in the rear block face.

The block ports extend in the axial direction through the block 7 from the rear face and open at their forward ends into the centres of arcua-te recesses 9a formed in the front face of the block. These arcuate recesses may have a width which is equal to or rather less than the diameter of the rear port openings in the block, and each extends over an angle of rather less than 180 around the front block face. To provide for smooth flow of pressure fluid, the recesses 9a are shaped internally so that they funnel smoothly int-o communication with the block ports 9.

The front face of the block through which the arcuate recesses 9a open has an upstanding rim 1%) therearound having diametrically opposed slots 10a therein, these slots being oifset by from the centres of the arcuate recesses 9a. This slotted rim It in conjunction with an upstanding centre boss 1% on the front block face, serves to position sealing means against the front face of the stator block. These sealing means consist, in this embodiment, of two flexible scaling rings 11 of rubber or rubber-like synthetic plastic material such as Nitrile and a disc 12 of low friction bearing material such as graphite nylon or polytetrafluoroethylene. As shown, the sealing rings 11 are disposed respectively around the rims of the two arcuate recesses 90 and are faced by the overlying low friction disc 12, which has a central aperture fitting over boss 10b and arcuate slots therethrough registering with recesses 9a. The thickness of disc 12 is such that it stands slightly proud of the boss b and of the rim 10 around the stator face. To prevent rotation of the disc 12 relative to the rimmed stator face, diametrically opposed projections 12a are provided on the disc which engage in the respective rim slots 10a. The width of the sealing rings 11 around the respective recesses is such that the angular extent of a recess 9a and associated sealing ring 11 is only slightly less than 180, as can be seen most clearly. in FIGURE 4.

Co-operating with the stator block 7 as described is a distribution rotor which conveniently takes the form of a cylindrical block 13. This rotor block is, in the illustrated embodiment, arranged to seat in a concentric recess in the outer face of the hub casing with the innermost end of the block positioned concentrically against the recessed outer face of the stator block and in rubbing substantially leak-proof contact with the low friction disc 12. To locate the block 13 on the hub casing for rotation therewith, bolts indicated diagrammatically at 13a may be employed.

In this embodiment five flow and return ports 14 open through the inner end face of the distribution block 13, these flow and return ports being centered on the same radii as the stator block recesses 90. The flow and return ports are conveniently of slightly flattened form with rounded ends and extend for a short distance axially through the distribution block and thence outwardly through radial passages 15 to the block periphery. These radial passages opening through the block periphery are in turn arranged to register with the radial flow and return passages 6 which connect with the outer ends of cylinders 3. Any appropriate leak-proof connection can, of course, be provided between the passages 6 and 15.

.With the arrangement described, it will be appreciated that rotation of the hub will bring the ports 14 in the distribution block sequentially into communication with the pressure and exhaust ports through the stator block, it being possible for more than one distribution block port to be connected with a pressure or exhaust port via the appropriate recess 9a at the same time. The presence of the sealing means between the overlying faces of the stator and rotor blocks provides an effective seal as between the recesses 9a and, at the same time, prevents any substantial leakage as between the recesses in the stator block and the ports in the rotor block.

In the second embodiment of the invention illustrated in FIGURES 6 to 10, the distribution valve is shown as having a stator block 16 of cylindrical form and bolted to the outer end of a cam shaft 17 by bolts 18. The stator block 16 has axial pressure and

exhaust ports

19 and 20 opening from the rear face thereof and extending over approximately half the axial length of the block, these pressure and

exhaust ports

19 and 20 being again relatively displaced by 180 to register with pressure and

exhaust passages

21 and 22 formed through the cam shaft. The inner ends of the pressure and

exhaust ports

19 and 20 in the stator block open into arcuate recesses 23 formed in the peripheral face of the block. These recesses are conveniently formed with inset locating channels around the rims thereof each containing sealing means 24 constituted, for example, by an endless flexible sealing ring with a facing strip of low friction synthetic plastic bearing material such as nylon or polytetrafluoroethylene. Each recess 23 and its seal 24 are together dimensioned to extend over only slightly less than 180 of the block periphery, whilst the thickness of the sealing means is such that the latter will stand proud of the peripheral block surface.

To co-operate with the cylindrical stator block 16, a distribution rotor in the form of a concentric ported sleevev 25 is mounted around the stator block 16 in an opening 26 provided through the hub casing, coaxial with cam shaft 17. The rotor sleeve 25 is connected for rotation with the hub by ,keys such as 27 and is conveniently retained within the hub opening by a cap 28 secured by bolts 29 to the hub body. Five radial ports 30 are formed through the rotor sleeve in this embodiment and axially positioned sequentially to register with the recesses 23. Again, the sealing means 24 serves to seal the two recesses 23 in the stator block from one another and also to prevent or inhibit leakage between the overlying faces of the stator and rotor. The ports 39 in the rotor connect with fiow and return passages 31 which, in this embodiment, are formed in the hub casing. As in the previous embodiment, these passages 31 connect, at their outer ends, with hydraulic hub cylinders.

The arrangement of the distribution valve as described in either of the foregoing embodiments, increases the tolerance allowed in manufacture of the valve parts, since the sealing means between the rotor and stator can be made effective to seal off the pressure and exhaust ports in the stator, even when a slight play exists between the rotor and stator members.

What is claimed is:

1. A hydraulic distribution valve having a stator block and a rotor arranged for rotatable mounting relative to the stator block, with a front face of said stator block opposed to a face of said rotor, sealing means'comprising flexible sealing rings faced with low friction bearing material interposed between said overlying stator and rotor faces to provide substantially sealed connections between the stator and rotor, said stator block being of circular plate-like form and having pressure and exhaust ports opening therethrough from a rear face to a front face of said stator block, said pressure and exhaust ports being displaced from each other by approximately degrees, and said pressure and exhaust ports extending from circular openings in the rear face of said stator to open through centers of arcuate recesses formed in the front face of the stator block, said arcuate recesses each extending over an angle of less than 180 degrees around the front face of said stator block and being shaped internally to funnel smoothly into communication with the stator block ports, and the front face of said stator block further including an upstanding center boss and an upstanding edge rim for locking said sealing means within said arcuate recesses with the flexible sealing rings of said sealing means being disposed around the lips of each said arcuate recesses, said low friction bearing material of said sealing means being in the form of an overlying facing disc having a center opening fitting over said center boss and having arcuate slots in said disc registering with the arcuate recesses of said stator block said facing disc being disposed over said flexible rings, said facing disc standing above said edge rim and said center boss, and ports through the face of said rotor whereby the rotor ports are positioned to register alternately with said stator recesses during relative rotation of the rotor to the stator.

2. A hydraulic distribution valve as claimed in claim 1, wherein the distribution rotor is in the form of a cylindrical block which is rotatably mounted with an inner end face in concentric sliding contact with the low friction bearing disc on the front stator block face, said rotor inner end face having a plurality of ports disposed concentrically therearound and centered on the same radii as the stator block recesses, the said rotor ports being extended axially through the rotor block for a short distance and thence outwardly through radial passages to the block periphery.

3. A hydraulic distribution valve as claimed in claim 2, wherein the low friction bearing disc is held against rotation on the rimmed stator block face by projections on the disc engaging in slots in the aforesaid rim.

4. A hydraulic distribution valve as claimed in claim 3, wherein the said bearing disc is made of graphite nylon.

5. A hydraulic distribution valve as claimed in claim 4, wherein the flexible sealing rings are made of rubber-like material.

(References on following page) References Cited by the Examiner UNITED STATES PATENTS Dickson et a1 91-204 Peck 91-204 Mills et a1 277-92 6 2,373,443 4/ 1945 Armington 277-92 2,525,498 10/1950 Naylor et a1. 103-161 2,557,508 6/1951 Leibing 103-161 SAMUEL LEVINE, Primary Examiner. FRED E. ENGELTHALER, Examiner.

Claims

1. A HYDRAULIC DISTRIBUTION VALVE HAVING A STATOR BLOCK AND A ROTOR ARRANGED FOR ROTATABLE MOUNTING RELATIVE TO THE STATOR BLOCK, WITH RESPECT FACE OF SAID STATOR BLOCK OPPOSED TO A FACE OF SAID ROTOR, SEALING MEANS COMPRISING FLEXIBLE SEALING RINGS FACED WITH LOW FRICTION BEARING MATERIAL INTERPOSED BETWEEN SAID OVERLYING STATOR AND ROTOR FACES TO PROVIDE SUBSTANTIALLY SEALED CONNECTIONS BETWEEN THE STATOR AND ROTOR, SAID STATOR BLOCK BEING OF CIRCULAR PLATE-LIKE FORM AND HAVING PRESSURE AND EXHAUST PORTS OPENING THERETHROUGH FROM A REAR FACE TO A FRONT FACE OF SAID STATOR BLOCK, SAID PRESSURE AND EXHAUST PORTS BEING DISPLACED FROM EACH OTHER BY APPROXIMATELY 180 DEGREES, AND SAID PRESSURE AND EXHAUST PORTS EXTENDING FROM CIRCULAR OPENINGS IN THE EAR FACE OF SAID STATOR TO OPEN THROUGH CENTERS OF ARCUATE RECESSES FORMED IN THE FRONT FACE OF THE STATOR BLOCK, SAID ARCUATE RECESSES EACH EXTENDING OVER AN ANGLE OF LESS THAN 180 DEGREES AROUND THE FRONT FACE OF SAID STATOR BLOCK AND BEING SHAPED INTERNALLY TO FUNNEL SMOOTHLY INTO COMMUNICATION WITH THE STATOR BLOCK PORTS, AND THE FRONT FACE OF SAID STATOR BLOCK FURTHER INCLUDING AN UPSTANDING CENTER BOSS AND AN UPSTANDING EDGE RIM FOR LOCKING SAID SEALING MEANS WITHIN SAID ARCUATE RECESSES WITH THE FLEXIBLE RINGS OF SAID SEALING MEANS BEING DISPOSED AROUND THE LIPS OF EACH SAID ARCUATE RECESSES, SAID LOW FRICTION BEARING MATERIAL OF