US2787959A - Power transmission - Google Patents

Description

POWER TRANSMISSION s Shdets-Sheet 1 Filed May 10, 195? N hA \nr\\ ff/u N w: o I oud m 5? m: @9 x mm mm 0 mm 3 mm om mm oh 3 mm mm m ow mm mgwzzvroas JOHN E JEANNIN By ROBERT A. EGGE ATTORNEY- April 9, 1957 J. F. JEANNIN ET'AL 2,787,959

POWER TRANSMISSION Filed May 10, 1952 5 Sheets-Sheet 2 INVENTORS JOHN E JEANNIN ROBERT A. EGGE BY ATTORNEY.

April 9, 1957 J. F. JEANNIN ET AL POWER TRANSMISSION 5 She ets-Sheet 3 Filed May 10, 1952 INVENTORS JOHN E JEANNIN ROBERT A. EGGE FIG. 4

ATTORNEY POWER TRANSMISSION JohnI Jeannin, Detroit, and Robert A. Eggs, Plymouth, Mich, assignors to Vickers Incorporated, Detroit, Mich, a corporation of Michigan Application May 10, 1952, Serial No. 287,224

1 Claim. (Cl. 103--3) This invention relates to power transmissions, and is nited States Patent particularly applicable to those of the type comprising two or more fluid pressure energy translating devices, one of which may function as a pump and another as a fluid motor.

The invention is more particularly concerned with a vane pump of the reversible variable displacement type.

Fixed displacement vane type fluid pumps having their rotor eccentrically positioned in a cylindrical working chamber are in wide use today. This is attributable in part to low initial cost and to very satisfactory service record in applications in which pressure requirements are not too severe. Efiorts to design such a vane pump having its displacement variable by means provided for selectively adjusting the eccentricity between the working chambers and the rotor have been made in the past. These efforts have met with rather-limited success since the devices have been characterized by bulky, heavy, and expensive construction. Further, the volumetric efiiciency of such pumps is often lowered from that of their fixed displacement counterparts by design compromises made in incorporating the displacement adjusting means.

It is an object of the present invention to provide an improved vane pump construction in which the output of the pump can be smoothly varied between zero and full capacity andin either direction of flow without reversing the direction of the pump shaft rotation.

A further object is to provide such a pump which is light in weight, compact, and efficient in operation.

Another object is to provide such a pump of rugged reliable construction which may be economically produced.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the present invention is clearly shown.

In the drawings:

Figure 1 is a transverse section of a variable vane pump embodying the present invention taken on line 1-1 of Figure 2.

Figure 2 is an axial ure 1. i

Figure 3 is a partial section taken on line 3-3 of Figure 2.

Figure 4 is a section taken on line 4-4 of Figure 3.

Figures 5, 6, and 7 are schematic diagrams of the displacement varying mechanism in various positions.

Figure 8 is a view showing the present invention in driving relation with a prime mover.

Referring now to Figure 1 there is shown a reversible variable delivery vane pumpdt) comprising a housing 12 having inlet and outlet passages .14, and 16 therein. interposed between those passages is a cylindrical pumping chamber 18, formed in a ring 20 having a plurality of holes 22 extending between the chamber 18 and the passages 14 and 16. A rotor 24, carrying a plurality of vanes 26 which are slidable into engagement with chamber 18 in substantially radial slots 28, is positioned section taken on line 2-2 of Figin chamber 18. Ports 29 supply pressure to the inner ends of vanes 26, thus maintaining them radially outward against the chamber 18.

Rotor 24, as most clearly shown in Figure 2, is carried intermediate the ends of a shaft 30 equipped with a multiple V-b'elt pulley 32 keyed to one end thereof. A pair of cheek plates 34 and 36 are biased into abutment with the ends of ring 20 by springs 38 as shown in Figure 3. Check plates 34 and 36 are provided with central openings 40 and 42, respectively, which provide substantial clearance around shaft 30 for a reason hereinafter-discussed. A pilot 44 on each of the cheek plates is provided with an 0 ring seal 46 and extends in fluid sealing axially sliding engagement into a central bore 48 in each of a pair of pressure chamber heads 50. Heads 50 are secured to the housing 12 by bolts 52 and dowel pins 54. Dowel pins 56 extending between heads 50, cheek plates 34 and 36, and the ring 20 insure against relative angular motion of those parts.

A valve block 58 mounted atop the housing 12 contains a pair of check valves 60 and 62 connected to ports 14 and 16, respectively, by a pair of fluid passages 64 and 66. Valves 60 and 62 cooperate in a well known manner to maintain pressure in the connecting passage 63 at whichever is the higher pressure, that in port 14 or that in port 16. Passage 68 connects through an intermediate passage 70, a branched passage 72 in housing 12 and passages 74 in the heads 50 to two annular pressure chambers 76 between the heads 50 and the cheek plates 34 and 36. Pressurein each chamber 76 biases the cheek plates 34 and 36 into axial fluid sealing relation with ring 20, vanes 26, and the rotor 24.

vided forshifting rotor24 relative to'pumping chamber 18 includes a pair of cam supports 78 secured to the housing 12 by bolts 80 and 82. O ring seals 83 are provided to insure a fluid tight junction between the cam supports and the housing. Cam supports 78 each have a bore 84 therein which is eccentric relative to the chamber 18. The bores 84 provide bearings for a pair of circular cams 86, each provided with an eccentric bearing bore 88 having a shaft bearing 90 therein. 0 ring seals91 between bores 84- and cams 86 permit relative rotary motion but prevent fluid leakage therebetween. Shaft 30 is supported between the two bearings 90 which transmit radial and axial loads on the shaft through cams 86 and cam supports 78 to the housing 12.

The eccentricity of bore 34, relative to chamber 18, is preferably equal to the eccentricity of bore 88, relative to bore 84. Such an arrangement provides a-center or zero displacement position in which the axis of shaft 39, and hence thatof rotor 24, is coincident with that of chamber 18. Rotation of cams 86 shifts shaft 30 and rotor 24 to vary the displacement and direction of pumping dependent onthe direction anddegree of rotation of' shaft 34 are thus'concentric with chamber 18. In Figure- 6,Vcam -86 has been rotatedclockwise-about its center, and shaft 3t) and. rotor '24- havethus been shifted:to ;a-

position of maximum eccentricity, indicated at 93, relative to chamber 18. Figure 7 is similar to Figure 6 except cam 86 has been rotated counterclockwise so as to produce opposite movement of the shaft and rotor. It should be noted that the eccentricity of cam 36 is made the output of the pump through its full range in both directions.

In Figures 5, 6, and 7, means for rotating the came 36 are schematically indicated by the lever 92secured at one end to cam 86 and having forces 94 and 96 applicable thereto. The actual embodiment of these means includes a pair of arms 98 secured to the cams 86 by a plurality of bolts 100. Arms 98 each have a central aperture 102 through which the ends of shaft 30 pass, and are provided with ring seals 104 which insure a fluid tight juncture with the cams 86. A cross arm 106 connects the arms 98 and is secured thereto by bolts 108. A U-shaped bracket 110 is rigidly fastened to cross arm 106 by a key 112 and bolts 114 and is provided with a thrust pin 116. It can be seen that cross arm 106 and arms 98 comprise a yoke through which simultaneous rotation of the cams 86 can be effected.

Provisions for applying a shifting force to the yoke include a pair of cylinders 118 and 120 mounted in the housing 12 and having pistons 122 and 124, respectively, therein. The piston rods 126 bear against the pin 116 to permit the pistons to apply force to the yoke. Adjustable stops 128 are provided for the pistons thus enabling independent adjustment of the maximum pump displacement in either direction.

Bolts 100, in addition to securing arms 98 to cams 86, also serve to retain a pair of end bells 130 and 132. Each end bell has a bore 134 which is concentric with shaft 30 and has a bushing 136 therein. Bushings 136 do not serve primarily a bearing function but rather, provide shaft seals with a metered bleed from the interior of the pump case, to prevent excessive pressure buildup therein. Bore 134 in end bell 130 is closed at its outer end by a plate 138 but is equipped with a bleed port 140, as shown in Figure 3, to permit removal of the bleed oil. Bore 134 in end bell 132 has a similar bleed port therein, not shown, and carries a conventional shaft seal 142 at its outer end. 0 ring seals 144 insure fluid tight junctures between the end bells 130 and 132 and the arms 98.

A floor plate 146 is provided to which the housing 12 is secured by bolts 148. Sheet metal dirt shields 150 cover the end of the unit and are fastened thereto by screws 152 and bolts 80. Spacers 154' are utilized to properly position the dirt shields 150 to come into sliding contactrwith the end bells 130 and 132 as shown at 156.

As the displacement of pump is varied, the axis of shaft 30 describes an are about the axis of cams 86 as heretofore described. One half of that are is indicated at 158 in Figure 6 and the other half at 160 in Figure 7. Coupling such a translatable shaft to a prime mover presents a problem. The present invention proposes to arrange the pump 10 and a prime mover 162 as shown in Figure 8 and connect them by a flexible coupling such as belt 164. The center of the prime mover pulley 163 lies on an extension of the central radius of the arcuate path 166 of pulley 32 and on the convex side of that arcuate path. Such an arrangement provides for a small change in center distance between the pulleys as the pump displacement is varied from zero to maximum and further, insures that the change increases the center distance as the displacement increases, thus tightening the belt to provide the greatest driving force when needed.

In operation, assuming clockwise rotation of rotor 24 and shaft 30 as viewed in Figures 1 and 4, no fluid will be pumped with rotor 24 in the center position shown. It can be seen, however, that application of fluid pressure to port 130 of cylinder 118 will cause piston 122 to move to the left causing clockwise rotation of cams 86 thus shifting rotor 24 downward. Fluid will then be pumped through chamber 18 from left to right making passage 14 the inlet and passage 16 the outlet. Conversely, application of pressure to port 132 of cylinder 120 will cause rotor 24 to move upward thus making passage 16 the inlet and passage 14 the outlet. As heretofore explained, the check valves 60 and 62 coact to maintain outlet pressure in pressure chambers 76 thus keeping cheek plates 34 and 36 in abutment with ring and rotor 24 to prevent leakage from chamber 18. The openings 40 and 42 in the check plates permit interference free translatory motion of shaft to vary or reverse the pump delivery.

It will be seen that the present invention provides a compact rugged structure capable of providing a reversible and variable output of fluid. The construction furthermore provides several practical advantages, among them being that the circular cam arrangement and the end bells carried thereby permit sealing the housing at the shaft openings by the use of rotary seals only. This is true even though motion of the shaft, with respect to the housing, is translatory. Another advantage is that the large eccentricity of the cams permits full variation of the pump displacement accompanied by a relatively small rotation of the cam. Such an arrangement permits use of a very simple mechanism for rotating the cam. In addition, the combination of a prime mover with the device in the manner shown provides an ideal drive since an increase in displacement results in an increase in belt tension, thus increasing its load transmitting ability.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to bc understoodthat other forms might be adopted, all coming within the scope of the claim which follows.

i What is claimed is as follows:

In combination; a fluid pressure energy translating dcvice having a casing, a working chamber in said casing, a rotary fluid impeller mounted in said chamber, an impeller drive shaft rotatably supporting said impeller, and means for shifting said impeller drive shaft through an arcuate path to either side of a central, non-delivery position to vary the displacement of the device; a rotary prime mover located on the convex side of said arcuate path having a drive shaft with its axis disposedso as to be parallel to said impeller drive shaft and to perpendicularly intersect an extension of the central radius of said arcuate path; and a flexible, endless driving connection between the prime mover drive shaft and the impeller drive shaft.

References Cited in the file of this patent UNITED STATES PATENTS 1,051,360 Wisdom Ian. 21, 1913 1,970,681 Zimmerer Aug. 21, 1934 2,098,652 Buckbee Nov. 9, 1937 2,387,761 Kendrick Oct. 30, 1945 2,414,187 Borsting Jan. 14, 1947 2,485,240 Jackson Oct. 18, 1949 2,543,603 Schatzel Feb. 27, 1951 2,600,633 French June 17, 1952 2,604,853 Taylor July 29, 1952 2,612,114 Ernst Sept. 30, 1952 2,628,567 De Lancey et a1 Feb. 17, 1953 2,646,004 Bergen July 21, 1953 2,656,796 Garner et al Oct. 27, 1953 FOREIGN PATENTS 318,871 Great Britain Sept. 11, 1929 551,680 France Jan. 11, 1923

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