US2575528A

US2575528A - Hydraulic fluid mechanism

Info

Publication number: US2575528A
Application number: US687399A
Authority: US
Inventors: John W Overbeke
Original assignee: Individual
Current assignee: Individual
Priority date: 1946-07-31
Filing date: 1946-07-31
Publication date: 1951-11-20
Anticipated expiration: 1968-11-20

Description

Nov. 20, 1951 J. w. OVERBEKE HYDRAULIC FLUID MECHANISM 2 SHEETS-SHEET 1 Filed July 51, 1946 ATTORNEYS INVENTOR. JOHN- W. OVEEBEKE' ====rihl|ll L==== Nov. 20, 1951 J w QVERBEKE 2,575,528

HYDRAULIC FLUID MECHANISM Filed July 31, 1946 v 2 SHEETSSHEET 2 INVENTOR. 70 H/V W- OVEIEBEAE ATTOR EY;

Patented Nov. 20, 1951 UNITED STATES PATENT OFFICE HYDRAULIC FLUID MECHANISM John W. Overbeke, Cleveland, Ohio Application July 31, 1946, Serial No. 687,399

7 Claims. (Cl. 103-161) This invention relates to fluid motors and pumps of the positive displacement type, and more specifically to improvements in mechanism for actuating the pistons therein. The invention is particularly adapted for use in pumps of the type provided with a rotating cylinder block having radial cylinders, and an eccentric ring that guides the pistons in their reciprocating movement within the cylinders, although the princip ples of the invention may be employed in pumps of other types.

It has been common practice to provide radial cylinder pumps with a stationary eccentric guiding ring circumambient the cylinder block and to provide arcuate shoes on the outer ends of the pistons for sliding engagement with the inner surface of the guiding ring. It has also been proposed to mount the guide ring for free rotation within the pump casing and to effect the movement thereof with the cylinder block by the frictional resistance between the piston shoes and the ring.

This invention is directed to the provision of a positive drive coupling between the cylinder block and the guide ring or track and to a structure which will eifect a rotary motion of the pistons within the cylinders in order to equalize the wear upon the cylindrical parts. The invention further contemplates the elimination of the piston shoes by virtue of which the overall dimensions of the pump may be greatly reduced, the frictional losses and wear minimized, and the operative efliciency of the pump increased. In the type of construction embodying piston shoes engaged with a fixed track, the proportions of the pump frequently exceed the dimensional limitations of the mechanism with which the pump is associated; the restriction against rotation of the pistons increases the probability of cylinder scoring; and the weight of reciprocating parts and inertia effects thereof increases the friction losses of the pump. Furthermore, this invention makes practicable the use of a rigid rotating ring for receiving and distributing the piston reaction forces, which ring may have a continuous bearing surface in the casing which is easily lubricated.

While it would appear upon a cursory analysis that these problems could be solved by the provision of a freely rotatable track driven by frictional engagement of the pistons with the track, experiment has shown that this construction is unsatisfactory, since such structure is noisy in operation and is subject to undue wear of the pistons and associated parts. This apparently results from the fact that the track is disposed in eccentric relation to the cylinder block, hence the angular velocities of the pistons with respect to the center of rotation of the track are not all the same. The pistons must therefore slip circumterentially with respect to the ring.

While the hydraulic unit according to the invention is referred to herein as a pump, it will be recognized by those skilled in the art that the device may be used with equal facility as a motor. The term pump, as used herein, will therefore be understood as synonymous with the term motor and, in the appended claims, pump and motor will be construed as mechanical equivalents.

An object of the invention resides in the provision of a pump in which the pistons coact directly with a rotating guide.

Another object of the invention is the provision of a pump in which the piston guide is positively driven by the cylinder block.

Another object of the invention is to provide a positive displacement pump in which the pistons are rotated within the cylinders.

Another object of the invention is the provision of a pump in which inertia forces are minimized.

A further object of the invention is a provision of a radial cylinder positive displacement pump which is compact, light in weight, and smooth of operation.

Other objects and advantages more or less ancillary to the foregoing and the manner in which all the various objects are realized will appear in the following description, which, considered in connection with the accompanying drawings, sets forth the preferred embodiment of the invention.

For purposes of illustration, the invention is shown herein as embodied in a pump of the type disclosed in my copending application, Serial No. 637,699, for Hydraulic Fluid Mechanism, filed December 28, 1945, although it will be apparent that the invention may be embodied in pumps or other mechanisms of a different design.

Referring to the drawings:

Fig. 1 is a vertical section taken through the axis of the pump on the plane indicated by the line l| in Fig. 2;

Fig. 2 is a vertical section taken on the plane indicated by the line 2-2 in Fig. 1;

Fig. 3 is a horizontal section of the pump, taken on the plane indicated by the line 33 in Fig. 2;

Fig. 4 is a sectional view of a fragmentary portion of the pump, the section being taken on the plane indicated by the line 4-4 in Fig. 2;

Fig. 5 is an end elevational view of the pump rotor with the coupling ring in place;

Fig. 6 is a side elevational view of the pump rotor with the coupling ring in place;

Figs. '7, 8, and 9 are elevational views of the coupling ring;

Fig. 10 is an end view of the track ring;

Fig. 11 is an end view of the valve block; and

Fig. 12 is an elevational view of the valve plate.

The preferred embodiment of the pump embodies a casing 20 having a cover plate 2| secured thereon by bolts 23. A cylinder block 23 is mounted for rotation within the casing upon a hub 24 within a bushing a in the end wall of the casing and upon a thrust and Journal bearing 23 in a bore in the cover plate II. The cylinder block is formed with a trunnion or shaft 2! disposed in axial alignment with the hub 24 and mounted for rotation within the Journal bearing II. A broached socket 28 in the end of the shaft 31 provides for the reception of a coupling member 21a by means of which the pump is driven. Suitable sealing means to prevent leakage of fluid along the shaft 21. such. for example. as those disclosed in my above mentioned copending appllcation, may be mounted within the recess 29 in the cover plate I i.

The pump mechanism comprises a plurality of pistons ll mounted for reciprocation in radial cylinders 32 in the cylinder block 21 (Figs. 1 and 2) The movement of the pistons within the cylinders is effected by the engagement of the spherical outer ends so thereof with the inner surface of a ring or track 33 which is mounted in eccentric relation to the axis of rotation of the cylinder block 23. The fluid flow to and from each cylinder is effected through an opening 33 (Figs. 1 and 2) in a cylindrical valve block 38 which is mounted in the center of the cylinder block it for rotation therewith. The openings 33 communicate with elongated ports as (Figs. 3 and 11) formed in the face of the valve block 38. The cooperating part of the valve: mechanism comprises a valve plate 40 (Figs. 3 and 12) provided with elongated arcuate openings II and 2 disposed in radial alignment with the ports 38. The openings 4i and 42 constitute continuations of passages a and 42a (Fig. 3) in the casing II, which communicate respectively with the intake opening ll and the discharge opening 44 formed in a boss 45 of the casing 2|. During the outward movement of each piston, the corresponding port as overlies the opening ii in the valve plate 40, and during the discharge stroke of each piston, the port 39 will communicate with the discharge opening 42.

The valve plate In is restrained from rotation by dowel pins 43 (Fig. I) inserted in the valve plate and into the casing 20. In order to maintain the valve block 38 in seated engagement with the valve plate 40, a compression spring 47 (Fig.

8) is mounted in a bore 48 in the valve block and an axially aligned opening 4! in the cylinder block. A fluid seal between the cylinder block and the valve plate is effected through the provision of O-rings or other sealing devices 50 and ll. As will be seen in Fig. 4, dowels 32 inserted in openings in the cylinder block 23 and valve block It constrain these parts from rotation relative to each other.

As shown in Figs. 1 and 3, floating pistons 54 mounted in bores communicating with the openings N in the valve block 33 provide, under the action of the conflned fluid, a force against the surface I of the cylinder block 23 which maintains the valve block in intimate engagement with the valve plate It. The pistons II are provided with a sealing ring it in a circumferential groove in the central portions of the body thereof. A channel (Fig. 1) permits such fluid as may escape around the valve block and floating pistons to be thrown outward centrifugally into the casing.

The outer face of the cover plate II is preferably machined with a pilot bearing 88 to accommodate the alignment thereof with the prime ing the coupling. Drainage may be effected by removal of the threaded plugs 60 in the outer ends of the openings 58.

The structure so far disclosed corresponds to I that in the above-mentioned copending application, and is substantially identical therewith except for the form of the pistons and the guide ring or track. In the prior application, a fixed guide ring is shown, and the pistons are provided with shoes which slide upon the inner surface of the ring. In the pump embodying the present invention, the guide ring 33 (Figs. 1 and 2) is journaled for rotation in a bushing 63 mounted in the casing 28 and is restrained against axial movement by a shoulder 64 engaged with the bushing 63, and by a thrust bearing 65 mounted in the cover plate 2i. The ring is formed with an inwardly directed flange 66 and a bead 61 on the opposed marginal edge thereof. The ring 33 is positively driven by the rotor 23 through an Oldham type coupling illustrated generally in Fig. 6 and in further detail in Figs. 7, 8, and 9. The flange 68 of the ring 33 (Fig. 10) is machined with diametrically opposed slots 68 in the inner edge thereof which receive driving lugs 69 formed in a coupling ring Ill disposed in contiguous relation with the flange. The slots 68 in the ring are formed to facilitate the smooth sliding engagement of the lugs therein. The face of the ring 10 opposite the lugs 69 is formed with diametrically opposed sector projections 12, the inner vertical walls 13 of which are beveled for sliding engagement with similar ledges It in a plate It mounted upon the inner face of the cylinder block 23 (Fig. 6). The undercut ledges 13 and the spaced relation thereof form a dovetail connection by means of which the ring 10 may slide radially relative to the plate 15. The plate 15 may be fixed to the cylinder block 23 by countersunk flat-head machine screws ll (Figs. 5 and 6) or may be made integral therewith. The guide ways in the cylinder block 23 and ring 33 are normal to each other, hence, during the eccentric movement of the block, the ring 33 may shift radially relative thereto. With this construction the ring will attain the same'velocity of rotation as the cylinder block throughout the operative cycle of the pump. Since the ring is eccentric to the block, the engaging faces of the pistons will creep or slide circumferentlally to a limited extent in relation to the ring. Under the influence of the coupling, the sliding movement of the ring is uniform, hence there is no irregular movegagement with one or another of the pistons. ment of the ring resulting from frictional engagement with one or another of the pistons.

The relative movement of the ring and pistons is utilized to effect a rotary motion of the pistons within the cylinders during the reciprocation thereof. This is accomplished by forming the pistons with domed outer ends and constructing the inner surface ,of the ring at a slight angle to the medial axis of the pistons. Since the cylinders are perpendicular to the axis of rotation of the block and since the inner surface of the guide ring is divergent thereto, say, an angle of two degrees, thecontacting point of the piston will be engaged slightly to one side of the axis of the piston and as the pistons move back and forth circumferentially with respect to the ring. they will rotate or turn about their axis within the cylinders. This motion, combinedwith the reciprocating motion of the pistons, results in a helical motion of .the pistons, which will affect an even distribution of wear upon the engaged walls of the cylinders and thus minimize the tendency of the pistons to score the cylinder walls.

An important advantage inherent in the use of the Oldham type coupling is in the reduction of vibration. Pumps and motors of the type disclosed herein are used at high and varying speeds and loads, and, particularly in aircraft service, the weight must be minimized.

Vibration is usually eliminated by damping force or by employment of a resonating mass. It is apparentthat ahnost any mode of vibration, torsional, transverse, or longitudinal, of the cylinder block or casing, will result in relative movement of the parts of the coupling. This sliding movement will be accompanied by friction tending to damp out the vibrations.

Although the foregoing description is necessarily of a detailed character, in order that the invention may be completely set forth, it is to be understood that the specific terminology is not intended to be restrictive or confining, and that various rearrangements of parts and modifications of detail may be resorted to without departing from the scope or spirit of the invention as herein claimed.

I claim:

1. A hydraulic device comprising a casing supporting a fixed valve member at one end thereof, a cylinder block mounted for rotation in the casing, the fixed valve member having a valve face symmetric about the axis of rotation of the cylinder block, the cylinder block having radially directed cylinder openings and an axially directed opening extending into the cylinder block from the fixed valve end thereof, a movable valve member positioned in the axially directed opening and having a valve face cooperating with the face of the fixed valve member, the movable valve member being constrained to rotate with the cylinder block but free to move axially to engage the fixed valve member, the valve members having cooperating ports and passageways for conducting fiuid to and from the cylinder openings as the cylinder block rotates, pistons in the cylinder openings having domed outer ends, an annular member surrounding the cylinder block and mounted in the casing for rotation about an axis eccentric to the axis of the cylinder block, the inner surface of the annular member being slightly frustro-conical with respect to the axis of the annular member and the domed heads of the pistons bearing against that surface, and a coupling device between the cylinder block and the ring for positively driving the ring with the cylinder block, whereby the slight component of axial thrust due to the engagement of the domed heads of the pistons with the inner surface of the annular member serves to minimize relatiw vibration between the movable valve member and the cylinder block and the fixed valve member.

2. A hydraulic device comprising a casing having a valve end and a drive end and supporting a fixed valve member at the valve end thereof,

a cylinder block mounted for rotation in the casing, the fixed valve member having a valve face symmetric about the axis of rotation about the cylinder block, the cylinder block having radially directed cylinder openings and an axially directed opening extending into the valve block from the fixed valve end thereof, a movable valve member positioned in the directed opening and having a valve face cooperating with the face of e fixed valve member, the movable valve member being constrained to rotate with the cylinder block but free to move axially to engage the fixed valve member, the valve members having cooperating ports and passageways for conducting fluid to and from the cylinder openings as the cylinder block rotates, pistons in the cylinder openings having domed outer ends, a first annular member surrounding the cylinder block mounted for rotation about an axis eccentric to the axis of rotation of the cylinder block, the inner surface of the annular member being frustro-conical with respect to the axis thereof, the outer ends of the pistons bearing against that surface, the inner radius of the annular member being greater at the valve end thereof, and the member having an inwardly directed portion at the drive end thereof, an annular thrust bearing supported-by the housing and engaging the inwardly directed portion of the member for receiving axial thrust due to the engagement of the pistons with the conical surface, and a coupling device between the cylinder block and the annular member for positively driving the member with the cylinder block, whereby the slight component of axial thrust due to the engagement of the domed heads of the pistons with the inner surface of the annular member serves to minimize relative vibration between the cylinder block and the fixed valve member.

3. A hydraulic device comprising a casing having a valve end and a drive end and supporting a fixed valve member at the valve end thereof, a cylinder block mounted for rotation in the casing, the fixed valve member having a valve face symmetric about the axis of rotation about the cylinder block, the cylinder block having radially directed cylinder openings and an axially directed opening extending into the valve block from the fixed valve end thereof, a movable valve member positioned in the directed opening and having a valve face cooperating with the face of the fixed valve member, the movable valve member being constrained to rotate with the cylinder block but free to move axially to engage the fixed valve member, the valve members having cooperating ports and passageways for conducting fluid to and from the cylinder openings as the cylinder block rotates, pistons in the cylinder openings having domed outer ends, a first annular member surrounding the cylinder block mounted for rotation about an axis eccentric to the axis of rotation of the cylinder block, the inner surface oi the annular member being frustro-conical with respect to the xis thereof, the outer ends of the pistons bearing against that surface, the inner radius of the annular member being greater at the valve end thereof, and the member having an inwardly directed portion at they drive end thereof, an annular thrust bearing supported by the housing and engaging the inwardly directed portion of the member for receiving axial thrust due to the engagement of the pistons with the conical surface, and a second annular member disposed within the first annular member and coupled to the cylinder block for relative motion in a first radial direction and coupled to the first annular member for relative motion in a second radial direction normal to the first.

4. A hydraulic device comprising a casing, a cylinder block mounted for rotation in the caling, the cylinder block having radially directed cylinder openings, valve means comprising a fixed valve member supported at one end of the casing having a valve face in a plane normal to the axis of rotation of the block and means associated with the block defining a valve face cooperating with the face of the fixed valve member, the valve means having cooperating ports and passageways for conducting fluid to and from the cylinder openings as the cylinder block rotates, pistons in the cylinder openings having domed outer ends, an annular member surrounding the cylinder block and mounted in the casing for rotation about an axis eccentric to the axis of the cylinder block, the inner surface of the annular member being slightly frustro-conical with respect to the axis of the member and the domed heads of the pistons bearing against that surface, the valve end of the ring having the greater inner radius, and a coupling device between the cylinder block and the annular member for positively driving the member with the cylinder block, whereby the slight component of axial thrust due to the en gagement of the domed heads of the pistons with the inner surface of the member serves to minimize relative vibration between the cylinder block and the fixed valve member.

5. A hydraulic device comprising a casing, a cylinder block mounted for rotation in the casing, the cylinder block having radially directed cylinder openings, valve means comprising a fixed valve member supported at one end of the casing having a valve face in a plane normal to the axis of rotation of the block and means associated with the block defining a valve face cooperating with the face of the fixed valve member, the valve means having cooperating ports and passageways for conducting fluid to and from the cylinder openings as the cylinder block rotates, pistons in the cylinder openings having domed outer ends, an annular member surrounding the cylinder block and mounted in the casing for rotation about an axis eccentric to the axis of the cylinder block, the inner surface of the annular member being slightly frustro-conical with respect to the axis of the member and the domed heads of the pistons bearing against that surface, the valve end of the member having the greater inner radius, and a ring surrounding said block and mounted on the block to slide in a single radial direction with respect thereto, the ring being within the annular member, axial projections from said ring engaging a bifurcated inwardly directed portion of the annular member, the ring being thereby constrained to move in a radial direction normal to the direction of motion of the ring with respect to the cylinder block.

6. A hydraulic device comprising a casing having a valve end and a drive end, a cylinder block mounted for rotation in the casing, the cylinder block having radially directed cylinder openings, valve means comprising a fixed means associated with the casing and rotatable means associated with the cylinder block, the valve means being rotationally symmetric about the axis of rotation of the cylinder block and defining a valve face generally normal to the axis of rotation of the block, the valve members having cooperating ports and passageways for conducting fluid to and from the cylinder openings as the cylinder block rotates, pistons in the cylinder openings having domed outer ends, a first annular member surrounding the cylinder block mounted for rotation about an axis eccentric to the axis of rotation of the cylinder block, the inner surface of the annular member being frustro-conical with respect to the axis thereof, the outer ends of the pistons bearing against that surface, the inner radius of the annular member being greater at the valve end thereof, and the member having an inwardly directed portion at the drive end thereof, an annular thrustbearing supported by the housing and engaging the inwardly directed portion of the member for receiving axial thrust due to the engagement of the pistons with the concial surface, and a coupling device between the cylinder block and the annular member for positively driving the member with the cylinder block, whereby the slight component of axial thrust due to the engagement of the domed heads of the pistons with the inner surface of the annular member serves to minimize vibration of the cylinder block.

'7. A hydraulic device comprising a casing having a valve end and a drive end, a cylinder block mounted for rotation in the casing, the cylinder block having radially directed cylinder openings, valve means comprising a fixed means associated with the casing and rotatable means associated with the cylinder block, the valve means being rotationally symmetric about the axis of rotation of the cylinder block and defining a valve face generally normal to the axis of rotation of the block, the valve members having cooperating ports and passageways for conducting fiuid to and from the cylinder openings as the cylinder block rctates, pistons in the cylinder openings having domed outer ends, a first annular member surrounding the cylinder block mounted for rotation about an axis eccentric to the axis of rotation of the cylinder block, the inner surface of the annular member being frustro-conical with respect to the axis thereof, the outer ends of the pistons bearing against that surface, the inner radius of the annular member being greater at the valve end thereof, and the member having an inwardly directed portion at the drive end thereof, an annular thrust bearing supported by the housing and engaging the inwardly directed portion of the member for receiving axial thrust due to the engagement of the pistons with the conical surface, and a second annular member disposed within the first annular member and coupled to the cylinder block for relative motion in a first radial direction and coupled to the first annular member for relative motion in a second radial direction normal to the first.

JOHN W. OVERBEKE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,006,880 Benedek July 2, 1935 2,035,647 Ferris Mar. 31, 1936 2,262,593 Thomas Nov. 11, 1941 2,273,468 Ferris Feb, 17, 1942 2,406,138 Ferris et al. Aug. 20, 1946 2,454,418 Zimmermann Nov. 23, 1948 2,457,101 Horton Dec. 21, 1948 FOREIGN PATENTS Number Country Date 649,437 France 1928