US2862455A

US2862455A - Hydrodynamic machine

Info

Publication number: US2862455A
Application number: US454124A
Authority: US
Inventors: Ferris Walter
Original assignee: Oilgear Co
Current assignee: Oilgear Co
Priority date: 1954-09-03
Filing date: 1954-09-03
Publication date: 1958-12-02
Anticipated expiration: 1975-12-02

Description

Dec. 2, 1958 w, FERR' 2,862,455

HYDRODYNAMIC MACHINE" Filed Sept. 3. 1954 v 3 Sheets-Sheet 1 Hal . x 7 N 7 1 2 6 a 27 /L 3 I Lil l1? l;' y; i 'LL 9 INVENTOR WALTER F ERRIS A TORNEY Dec. 2, 1958 w FERRls 2,862,455

HYDRODYNAMIC MACHINE Filed Sept. 3. 1954 3 Sheets-Sheet 3 as 22 I FIG. 4 24 I I iNVENTOR WALTER FERRIS.

ATTORNEY United States Patent I HYDRODYNAMIC MACHINE Walter Ferris, Milwaukee, Wis., assignor to The Oilgear Company, Milwaukee, Wis., a corporation of Wisconsin Application September 3, 1954, Serial No. 454,124

' 4 Claims. (Cl. 103-161) This invention relates to hydrodynamic machines of the type having two relatively rotatable members one of which has pistons and cylinders arranged therein and the other of which effects reciprocation of the pistons during relative rotation of the members. Such a machine will function as a pump when the rotatable member is driven mechanically or it will function as a motor when each of its cylinders is supplied with liquid from a pressure source during one-half of each revolution of the rotatable member and is connected to discharge during the other half of each revolution of the rotatable member.

' Since the operation of a machine when functioning as a motor is substantially opposite to the operation of a machine when functioning as a pump, the present invention will be described andclaimed herein as being embodied in a pump inorder to simplify the explanation but the jinvention is equally applicable to a motor and it is to be understood that the term pump as used herein is in tended to include motors-and machines which will functiorieither as pumps or motors. i v

The invention has as an object to provide a machine having 'a novel arrangement of pistons, cylinders and piston reciprocating means. Another object of the invention is to provide a fluid bearing support for the friction free rotation of a thrust transmitting ball that'reciprocates the piston of a radial piston type pump.

The invention is exemplified by the pump shown in the accompanying drawings in whichthe views are as follows:

. bore 23 near the outer end thereof.

v.:Fig.v l is a central longitudinal section througha pump I i in which the invention is embodied, the view being taken onithe line 11 of'Fig. 2 and the endportions of the pump being omitted-in order to show the parts on as large a'scale as possible. l Fig. 2 is'a transverse section taken on the line 2-2 of Fig. 1,-the side portions of the pump casing and the displacementadjusting means being omitted since they'form no part ofthe present invention.

.Fig. 3 is a section through one of the piston assemblies. and portions of adjacent parts of the pump, the view a being taken on the line 3-3 of Fig. l but much larger scale. I i

Fig. 4. is a view similar to Fig. 3 but showing a ditferent. type of piston and cylinder assembly. [,The pump has its mechanism arranged within a casing 1 having formed therein a chamber2 which is closed at its rear. bythe integral rear wall 3 of casing 1 and at its front by a removable partition plate 4 held in position by an end head 5 fastened to casing-1, only portions of end head 5 being shown. I I

Liquid is conducted into and out of the pump through a central valve shaft or pintle. 6 which is fixed in rear wall 3 and extendsinto chamberz. The portion of pintle 6 within ,chamber 2 is reduced in diameter to provide a shoulder 7 and it has formed therein two diametrically opposed ports 8 and 9., which communicate, respectively, with two passages 1.0 and two passages 11 which extend rearward through pintle circuit.-

drawn to a .6 for connection to a hydraulic 2,862,455 l atented Dec. 2, 1958 Ice The pump has a plurality of pistons and cylinders arranged radially in a rotatable cylinder barrel 15 in one or more circular rows, two rows being shown. Cylinder barrel 15 may be journaled directly upon pintle 6 but it has been shown as having a sleeve or liner 16 pressed therein to form a part thereof and closely fitted upon pintle 6 to rotate thereon.

Rotation of cylinder barrel 15 is effected by drive shaft 17 which is connected thereto by suitable coupling means such as an Oldham coupling 18. Shaft 17 is journaled in suitable bearing means (not shown) carried by end head 5 and it has its inner end reduced in diameter and journaled in a bearing 19 arranged in the inner end of pintle 6. Axial movement of cylinder barrel 15 is prevented by coupling 18 and by a spacer ring 20 arranged between cylinder barrel 15 and shoulder 7.

Cylinder barrel 15 may have its cylinders formed directly therein but preferably the pumping cylinders are made separately and are inserted in suitable bores formed in cylinder barrel 15. In the form shown in Fig. 3, each piston and cylinder assembly includes an outer guide cylinder 21 of relatively large diameter and an inner pumping cylinder 22 which is smaller than cylinder 21 and concentric therewith.

Cylinders

21 and 22 may be separate units but they have been shown as being integral with each other to form a two-diameter cylinder and will be referred to herein as cylinder portion 21 and cylinder portion 22 respectively. 7 V

Cylinder portion 21 is closely fittedin a bore 23 which extends radially into cylinder barrel 15 from the periphery thereof. Cylinder portion 22 is closely fitted in a bore 24 which extends radially inward from the inner end of bore-23. Cylinder 21-22 is retained in position in any suitable manner such as bysmeans of a snap ring 25 arranged in a suitable groove formed in the wall of Bore 24 cornmuni cates at its inner end with a passage 26 which is formed in liner 16 and communicates with the adjacent'bore 2 4 in the other row of pistons and cylinders as shown in Fig. l. Liner 16 has a cylinder port 27 extending radially inward therefrom and adapted to register with pintle ports 8 and 9 alternately as cylinder barrel 15 rotates.

Each cylinder 21-22 has fitted'therein a piston comprising a pumping portion 30, which is closely fitted for reciprocation in cylinder portion 22, and a socket portion 31 which is closely fitted for reciprocation in cylinder l portion 21 and has a concavity or socket 32 having a direction.

spherical surface formed in its outer end. Each socket 32 has a ball 33 fitted therein and engaging a circular reaction surface 34 which is eccentric to cylinder barrel 15 when the pump is functioning.

Reaction surface 34 has been shown as being formed upon the interior of a thrust ring 35 rigidly secured within a displacement varying member or slide block 36 which extends around cylinder barrel 15 and is slidable in a horizontal plane transversely of the axis of cylinder barrel 15 but is restrained from movement in any other As shown, slide block 36 is restrained from axial movement by rear wall 3 and plate 4 and it is provided on its four corners with slide slide plates 38 carried by casing 1.

.The arrangement is such that, when the axis of slide a block 36' is offset toward the right from the axis of cylinder barrel 15 as shown in Fig. 2 and cylinder barrel 15 is rotated in the direction of the arrow, ,balls 33. will roll around surface 34 and will rotate in sockets 32, each piston 30-31 will move progressively outward as the ball therein rolls around the upper half of surface 34, and

each piston 30-31 will be forced progressively inward as the ball therein rolls around the lower half of surface 34. The outward moving pistons will draw liquid into their cylinders and the -associatedb0res24 through passages plates 37 which engage 26, port 8 and passages 10 from the circuit and the inward moving pistons will eject liquid from their cylinders and the associated bores 24 through passages 26, port 9 and passages 11 into the circuit.

Centrifugal force will urge the outward moving pistons 3031 against balls 33 and balls 33 against surface 34 but, in order to keep balls 33 in contact with surface 34 when the pump is idle and to enable the machine to function as a motor, each piston 30-31 preferably is held against a ball 33 and that ball 33 is held against surface 34 by a spring 39 arranged between the outer end of cylinder portion 22 and a shoulder formed on piston portion 31.

In order to provide lubrication for balls 33 to assure their free rotation relative to pistons 3 31 and to hydrostatically balance pistons 3031, each socket 32 has a recess 40 formed in the bottom thereof, a passage 41 is extended from recess 40 through the inner end of piston portion 30, and passage 41 is constructed to restrict the rate of flow of fluid therethrough and may include a re striction orifice for that purpose. As shown passage 41 has a reduced cross sectional area adjacent its opening to the smaller cylinder for restricting fluid flow. A drain groove 42 is formed in socket 32 at such a distance from the edge of recess 40 that the mean diameter of the zone 43 between recess 40 and groove 42 is approximately equal to the diameter of the pumping portion 30 of the piston, and groove 42 is drained in any suitable manner.

As shown, groove 42 is drained through one or more ducts 44 into the lower part of cylinder portion 21 which has a passage 45 extending therefrom through the periphery of cylinder barrel 15.

Any pressure acting upon the inner end of piston portion will extend through passage 41 into recess 40 and cause liquid to seep therefrom and form a film of liquid between ball 33 and socket .32 in the zone 43. The pressure in the film at the inner edge of zone 43 will be the same as the pressure in recess 40 and will be zero at the outer edge of zone 43 so that the average pressure in the film will be one-half the pressure in recess 40. Since the mean diameter of zone 43 is the same as the diameter of piston 30, the projected cross-sectional area of zone 43 is equal to twice the diiference between the crosssectional area of piston portion 30 and the projected crosssectional area of recess 40. Therefore, piston 3031 is hydrostatically balanced whenever the pump is in operation and the pumping forces will be transmitted from ball 33 to piston 3031 through the liquid in recess 40 and in zone 43 so that there will be no metal-to-metal contact between ball 33 and socket 32. This arrangement maintains fluid in recess 40 under substantially the same pressure as under piston 30 and provides an effective area on which such pressure may act to separate the ball from the piston and this area is at least equal to the pumping area of the piston so that the hydrostatic force tending to separate the ball and piston is equal to the thrust on the piston which forces it toward the ball. Since this condition prevails for any pressure in the small cylinder 26, a bed of fluid is maintained between the ball and the piston and provides friction free rotation for the ball relative to the piston with a minimum amount of fluid flow between recess 40 and drain groove 42. Thus the mean effective area of the socket portion of the piston enclosed by annular drain 42 and subject to the pumping pressure is equal to the effective pumping area of the piston. Rotation of ball 33 will cause it to carry liquid with it and form a lubricating film between it and the zone 46 outward from groove 42 but there will be no pressure in that film.

Making balls 33 larger in diameter than the pumping portions of the pistons and hydrostatically balancing the pistons enables the pump to create very high pressures and to have a long useful life.

Fig. 4

This figure shows a cylinder and piston assembly arranged in a cylinder barrel 15 of which only a portion has been shown as it is the same as cylinder barrel 15 except for the bores formed therein. The assembly includes a cylinder having a guide portion 21* which is formed in cylinder barrel 15 and a smaller pumping portion 22* which is pressed into a bore 24 extending radially inward from guide portion 21 into communication with one of the passages 26 formed in liner 16, a piston having a pumping portion 39* Which is fitted in cylinder portion 22 and a socket portion 31 which is fitted in cylinder portion 21 and has a concavity socket 32 having a spherical surface formed therein, and a ball 33 which is fitted in socket 32 and engages the reaction surface 34 on thrust ring 35. p

In order that the assembly may be used in a machine which can function as a motor, piston 30 -431 is urged against ball 33 and ball 33 is urged against the reaction surface 34 by a spring 39 arranged between the bottom of the guide portion 21 of the cylinder and a suitable shoulder formed upon the socket portion 31* of the piston.

The piston is hydrostatically balanced in the same manner as in Fig. 3. That is, a recess 40 is formed in socket 32 on the piston axis, a passage 4-1 extends from recess 4% through the piston into communication with a passage 26, and recess 41% is surrounded by a bearing zone 43 the mean diameter of which is approximately equal to the diameter of the pumping portion 36* of the piston. The piston and cylinder assembly function in the same way as that shown in Figs. l-3.

The invention herein set forth is susceptible of other modifications without departing from the scope thereof which is hereby claimed as follows:

1. A pump comprising a first member having at least one large cylinder extending into it from an outer face thereof and a smaller cylinder extending inward from the inner end of said large cylinder, a second member located adjacent to said first member and having a surface spaced from said face, means for rotating one of said members relative to the other members, said second member being so arranged that the distance between said surface and the outer end of said large cylinder increases and decreases alternately during rotation of said one member, valve means for controlling the flow of liquid to and from said smaller cylinder, a piston having a pumping portion fitted in said smaller cylinder and a socket portion fitted in said large cylinder, said socket portion of said piston having a spherical concavity defining a ball receiving socket, a ball fitted in said socket to rotate therein and to eifect reciprocation of said piston during rotation of said one member, a recess in said socket, an axial passageway extending through said piston and connecting said recess with said smaller. cylinder, an annular drain in the surface of said socket and spaced from said recess to enclose a mean effective area subject to the operating pressure in said smaller cylinder and equal to the effective pumping area of said piston so that a bed of fluid is maintained between said ball and socket for varying operating pressures With a minimum of fluid flow therebetween.

2. A pump comprising a first member having at least one large-cylinder extending into it from an outer face thereof and a smaller cylinder extending inward from the inner end of said large cylinder, a second member located adjacent to said first member and having a surface spaced from said face, means for rotating one of said-members relative to the other member, said second member being so arranged that the distance between said surface .and the outer end of said large cylinder increases and decreases alternately during rotation of said one member, valve means for controlling the flow of liquid to and from said cylinder, a piston having a pumping portion fitted in said smaller cylinder and a socket portion fitted in said large cylinder, said socket portion of said piston having a spherical concavity defining a ball receiving socket, a ball fitted in said socket to rotate therein and to efiect reciprocation of said piston during rotation of said one member, a recess in said socket, an axial passageway extending through said piston and connecting said recess with said smaller cylinder, an annular drain groove in the surface of said socket and spaced from said recess to define an area therebetween whose mean effective diameter subject to pumping pressure is equal to the diameter of the pumping portion of said piston.

3. A pump comprising a first member having at least one large cylinder extending into it from an outer face thereof and a smaller cylinder extending inward from the inner end of said large cylinder, a second member located adjacent to said first member and having a surface spaced from said face, means for rotating one of said members relative to the other member, said second member being so arranged that the distance between said surface and the outer end of said large cylinder increases and decreases alternately during rotation of said one member, valve means for controlling the flow of liquid to and from said cylinder, a piston having a pumping portion fitted in said smaller cylinder and a socket portion fitted in said large cylinder, said socket portion of said piston having a spherical concavity defining a ball receiving socket, a ball fitted in said socket to rotate therein and to efiect reciprocation of said piston during rotation of said one member, a recess in said piston and restricting the flow of fluid from said smaller cylinder to said recess, an annular drain groove in the surface of said socket and spaced from said recess to define an efiective bearing area therebetween equal to twice the difference of the effective pressure areas of the piston and of the recess so that a bed of fluid is maintained between said ball and socket for varying operating pressures.

4. A pump according to claim 3 including a spring disposed in said large cylinder between said smaller cylinder and said socket portion of said piston and operative to urge said piston against said ball to hold said ball in rolling engagement with said surface of said second member.

References Cited in the file of this patent UNITED STATES PATENTS 2,103,314 Benedek Dec. 28, 1937 2,506,974 Sorensen May 9, 1950 2,612,110 Delegard Sept. 30, 1952 2,646,755 Joy July 28, 1953 2,660,992 Roosa Dec. 1, 1953 2,674,196 Ferris Apr. 6, 1954 2,688,924 Links Sept. 14, 1954 2,716,944 Ferris Sept. 6, 1955