US2646003A - Vane track for hydrodynamic machines - Google Patents

Description

July 1, 1953 w. FERRIS VANE TRACK FOR HYDRODYNAMIC MACHINES Original Filed Nov. 9, 1946 FIG. 5

,124 iiimvsu'ron WALTER FERRIS FIG. 6

ATTORNEY motor.

Patented July 21 1953 VANE TRACK FOR HYDRODYNAMIC d I MACHINES Walter Ferris, Milwaukee, Wis., assignor to The Oilgear Company, Milwaukee, Wis.,a corporation of Wisconsin Original application November 9, 1946, Serial No. 709,019, now Patent No. 2,627,650, dated February 10, 1953. Divided and this application January 3, 1949, Serial No. 68,880

2 Claims. (Cl; 103-.-120) 1 This application is a division of application Serial No. 709,019, filed November 9, 1946, now Patent No. 2,627,650. The invention relates to variable displacement hydrodynamic machines of the slidable vane type and more particularly to the vane track of such a machine.

A slidable vane type hydrodynamic machine includes a rotor having a plurality of vane slots extending inward from its periphery, a vane slidable in each slot, two cheek plates which are closely fitted to opposite sides of the rotor and to opposite edges of the vanes, a spacer ring which extends around the rotor and forms with the cheek plates a chamber having a plurality of ports through which liquid flows to and from .the space between the rotor and the spacer ring, and a vane track upon which the outer ends of the vanes slide during rotation of the rotor.

' The vane track includes a plurality of abutments or bridges, with which the vanes coact to provide substantially liquid tight seals between the inlet and outlet ports of the machine, and a ,plurality'of track sections which are arranged between the bridges and form therewith a continuous track. The bridges are ordinarily arranged in pairs with one bridge of each pair ar-' ranged close to the periphery of the rotor and with the other bridge spaced from the periphery of the rotor when the machine is performing useful work, the bridge which is close to the rotor being called the sealing bridge and the bridge which is spaced from the rotor being called the pumping bridge or the working bridge. If all the bridges are stationary, the displacement of the machine is constant but the displacement may be varied byproviding means to move the Working bridge of each pair toward and from the rotor. Vane type hydrodynamic machines are extensively used as pumps but a properly designed vane type hydrodynamic machine may function as a When the machine is used as a pump, its rotor is'ordinarily rotated at such a high'speed that the centrifugal force is s'ufficient to keep the vanes in contact with the track and it is only supplyinghigh pressure liquid to the inner ends of Ithe outward moving vanes.

c. When the working bridgesnof a machine have rotor and the rotor is rotated, each vane will move inward as its outer end moves from a working bridge toward the adjacent sealing bridge, it will move outward as its outer end moves from the sealing bridge toward the next working bridge, it will move inward as its outer end moves from that bridge towardthe next sealing bridge, and it will move outward as its outer end moves from that sealing bridge toward the first mentioned bridge. Each vane thus makes two reciprocations during each revolution of the rotor and, since the rotor is often driven at very high speeds, the reciprocations may be very rapid. 7

If the track is so shaped that it forces each vane inward too rapidly, the vane will tend to dig into the track and thus cause excessive wear of the track or the vane or both. If the slope of the track at any point is so steep that an outwardmoving van cannot follow it, the vane may leave the track at that point and reengage the track at another point with an impact that tends to damage both the track and the vane. Consequently, the shape of the track must be such as to provide gradual accelerations and decelerations of the vanes.

A track having a surface so shaped as to cause uniform accelerations and decelerations of the vanes would provide an ideal condition which may be approached in a unitary rigid vane track for a constant displacement machine but in a variable displacement machine the contour of the track will vary as the movable bridges are moved inward and outward to vary the displacement.

It has heretofore been proposed to provide vane tracks having flexible track sections fixed to the movable bridges but such prior vane tracks are so expensive to make that they are impractical for commercial use.

The present invention has as an object to provide a vane track having a plurality of movable bridges, a plurality of stationary bridges and of a hydrodynamic machine having a vane track in which the invention is embodied, the view being 3 taken along the faces of the rotor and the spacer ring and Showing the movable bridge in zero displacement position.

Fig. 2 is a similar-section through the other half of the same machine and shows the movable bridge in maximum displacement position.

Fig. 3 is an enlarged View of the inner face'of one of the stationary bridges .shown in Figs, 1

and 2.

Fig. 4 is an end View of the bridge shown in Fig. 3.

Fig. 5 is a side view of one of :the movable bridges and the two flexible track sections formed integral therewith.

Fig. 6 is an end View .of the parts shown in Fig. 5.

The hydrodynamic machine shown in Figs, 1 and 2 is of the general type of the machine shown in Patent No. 2,141,170 to which reference may be had for details of construction. It is deemed sufficient to state herein that the machine has a rotor l fixed for rotation with a shaft 2 and arranged within a spacer ring 3, that rotor I has a plurality of vane slots 4 extending inward from periphery of spacer ring 3.

'Theouterendsof vanes 5 ride upon an endless vane track :comprising two stationary sealing bridges t8 :which are fixed in spacer ring 3 diametrically opposite each other and have their inner faees arranged close to the periphery of rotor'il .twosmovable working bridges 9 which are spaced 80 from bridges 8 and are slidable in spacer ring 3 toward and from rotor I, and four flexible arcuate track sections if) each of which ;is;forrnedt.integral with a movable bridge 9 and extends therefrom to the adjacent stationary bridge 8.

shown :in Figs. 3 and 4, each bridge 8 includes a *body portion i! having two integral extensions 12 :oneach end thereof and four abutments is each of which is closely fitted against an end'facezofbody portion -l l and against a side face of anaextension l2. Abutments E3 are rigidly secured in position by two pins i l each of which is closely fitted-in an extension 52 and in the two adjacent abutments l3 and which may be fixed in position by slightl upsetting its ends. Each bridge 8, including its abutments l3, is exactly thesame thickness as spacer ring 3 andistightly fitted in a recess l5 formed in the spacer ring 3.

The inner face it of body portion H is accurately and smoothly finished to a radius which preferably is equal to the distance between face it and the center of rotor l. The inner faces I! of extensions l2are straight, smooth and tangent to face it. Theinner end face It on each abutment I3 is straight, smooth and parallel to the adjacent face 13?.

Each bridge 9 is slidably fitted in a recess l9, which is fformedinspacer ring 3, and it is accurately and smoothly finished to such dimensions that it forms substantiallyliquid tight joints with the walls of recess l9 and with the inner faces of the cheek plates.

The'inner face'Zil of each bridge 9 is smoothly finished to a radius Which may be equal to the ""distancebetween-face 20 and the center of rotor I when bridge 9 is either in its zero displacement position, in its maximum displacement position or in an intermediate position but, for simplicity and economy in manufacture, it ordinarily is finished to the same radius to which the faces IE on bridges 8 are finished.

Bridgesi) ma be shifted to and held in adjusted positions in any suitable manner. As

.shown, each bridge 9 is provided with a recess 21 to receive the inner end of a control rod 22 which is fixed to bridge 9 by a pin 23 and extends radially outward through spacer ring 3, a hole 24 being provided in each bridge 9 to receive a pin .23. Control .rods 22 are operated in unison by mechanism not shown.

Each track section I0 is integral at one end with 'a bridge .9, as previously explained, and its inner face is smooth and forms a continuation of the face 20 on bridge 9. The other or free end of each track section lji) is provided with a notch .25 (Fig. 6) to enable it to straddle an extension l2 on a bridge 8 and to be supported upon the faces l8 of the adjacent abutments is as shown in Figs. 1 and 2. Track sections l0 ordinarily are initially bent to a radius enough greater than the radius of face 253 to cause the free ends thereof to remain in contact with faces H3 in all positions of bridge 9.

The free end of each section i9 is of a thickness exactly equal to the. distance between a face i'i and the adjacent face l8. Therefore, since faces l and is are parallel to each other, face H is substantially tangent to the inner face of track section it at all positions of bridge 9, thereby providing a smooth path for each vane 5 as it passes from a bridge 8 onto a track section If) and from a track section l6 onto a bridge 8.

In order to keep the radial accelerations and decelerations of the vanes well within the permissible limits, each track section Hi is gradually tapered from a maximum thickness at its free end to a minimum thickness adjacent bridge 9 to thereby cause'the portion of track section l0 adjacent bridge 9 to flex more than the free end portion thereof as bridge 9 is moved toward and from rotor l.

The accelerations and decelerations of the vanes are greatest when bridges 9 are in their maximum displacement positions but, if track sections iii are properly proportioned, there will be no abrupt changes in the rates of acceleration anddeceleration. For example, if the rotor is about three and one-half inches in diameter, the thickness of a track section at its thinnest part ma be about sixt per cent of the thickness at the free end.

The arrangement is such that the vane track will be substantially concentric with the rotor and no significant radial movement of the vanes will occur when bridges 9 are in their zero displacement positions as shown in Fig. 1 but, when bridges 9 are moved outward from their zero displacement positions, each vane will start to move gradually outward as it passes from a face l6 onto a face ll, it will gradually accelerate as it passes from that face ll onto the adjacent track section i0, it will continue to gradually accelerate until it reaches a point intermediate bridges 8 and 9 and then it will gradually decelerate until it passes onto the face 20 of the adjacent bridge 9. It will then have substantially no radial movement until it passes onto the next track section In and then it will start to move inward. It will gradually accelerate as it continues to move along track section Ill, itwillcontinue to gradually accelerate until it reaches a point intermediate the ends of section If) and then it will gradually decelerate until it passes onto face l6 of the next bridge 8 and then radial movement of the vane will cease as the vane moves across face 5. There are thus no abrupt changes in rates of radial acceleration and deceleration of the vanes and, consequently, abrasion of the ends of the vanes and of the vane track is negligible.

The vane track illustrated and described herein may be modified without departing from the scope of the invention which is hereby claimed as follows: t

1. An endless vane track of variable length comprising a plurality of alternate fixed and movable bridges spaced around a common center and having arcuate inner faces, two arcuate flexible vane track sections formed integral with each movable bridge and extending from opposite ends of the inner face thereof to the adjacent fixed bridges and having their inner faces forming continuations of the arcuate inner face on said movable bridge, extensions arranged upon opposite ends of each fixed bridge and having the inner faces thereof tangent to the arcuate inner face of that fixed bridge, and abutments fixed to said extensions to support the free ends of the adjacent track sections and having the inner tively thin adjacent said movable bridges and gradually increasing in thickness toward their free ends to thereby maintain proper curvatures of said sections in all positions of said movable bridges.

2. In a hydrodynamic machine having a rotor and a plurality of vanes slidable radially in said 6 rotor, the combination of two movable bridges and two fixed bridges spaced alternately around a common center and having arcuate inner faces, an extension arranged upon each end of each fixed bridge and having the inner face thereof tangent to the arcuate inner face of that fixed bridge, four flexible track sections arranged alternately with said bridges and forming there- With and with said extensions an endless vane track of variable length upon which the outer ends of said vanes ride during rotation of said rotor, each track section being formed integral at one end with a movable bridge and having its inner face forming a continuation of the inner face of that bridge and its other end bifurcated, and two abutments fixed to opposite sides of each of said extensions to support the bifurcated end of the adjacent track section, the abutments fixed to each extension having the inner faces thereof arranged approximately parallel to the inner face of that extension and spaced radially outward therefrom a distance substantially equal to but not less than the thickness of the bifurcated end of the track section supported thereon to thereby enable said abutments to hold the inner face of, that track section flush at one point with the innerface of that extension in all positions of the movable bridge with which that track section is formed integral, and said flexible track sections being relatively thin adjacent said movable bridges and gradually increasing in thickness toward their free ends to thereby maintain proper curvatures of said sections in all positions of said movable bridges.

WALTER FERRIS.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,482,011 Hiles Jan. 29, 1924 2,141,170 Centervall Dec. 27, 1938 2,141,171 Centervall Dec. 27, 1938 2,313,075 Kendrick Mar. 9, 1943 2,313,246 Kendrick Mar. 9, 1943 2,368,223 Kendrick Jan. 30, 1945

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