US2411602A - Pump for power transmissions - Google Patents

Description

Nov. 26, 1946.

R. L. TWEEDALE PUMP FOR POWER TRANSMISSION Filed Sept. 3, 1942 48 INVENTOR 'It isifan' object vide anirnprovedfpumping unit which may be so controlledias to.acta s its cwnrrelief valve orun- Patented 26,

" .to Vickers,Incorporated,lletroit lilichi,a corfbw e iit M miy i appu dnwisebum";

Q i i it I? This inventiongrelates to po wer Q particularly to those 01' the type comprising two 5 or more fluid pressure,energy-translating devices, one 01 which; may function asapump'and The inventionis more particu1arly..;concemed Y with a pumping unitof the rotarytype; and with control .means for regulating the volumetric dis-f ichargethereof.

member whichideflnes one .or more "pumping "passageway, either for limiting the: maximum pressurein' the pump ndischargefline or for com- 7 pletel'y' unloading the pump tor-permit it tecirr,

culate, iluid "idly. I

1 f; thief-present invention t6 pro-1 j [A in 'hepobject is to provide a=unit of this character wherein. the radial movement clothe v vanes relative to the rotor may be variably controlled ,toqthereby regulate thepumping :action and reduce 'or increase, .to any degree desired,- the .g Further 1 objects and advantages i the present inventl on will be apparentfromthe i'ollowing description;i' reference being had. togthe "accompanying drawing nwherein a preferred iorm; I a

of thei res'ent invention is :clearlyshown. 1

v Inithe drawing; a a n v Figure 1 is a longitudinal'cross section i a" pumpincorpc'ratin ap referred form of the presentinventiomj v H v "Figure 2 is a cross sectionjon-line 2- -2 oi -Figure 1; t

Figure 4 s a crossisectionon lineiH oi' lilg- Figure 5 is a cross sectiononline Eig ure 3; f n a a body [0 is provlded with a cylindrical recess l-2V in which a is ffitte d. atpuinpiri g, cartridget; i4, being retained therein by a' head plate re-' 5 The lflang'e's ll are provided withgro vesi 52 aha-swam. 4 1 v m my secured to th 6 is proyidedvwith asmaller ,arcuate pressure port '22 communicating with a pressure'z pipeiconnect1n2.' I

1' Ill isa drive shaft}! which at itsinne'r end has a splined connection jlxwith a cylindrical rotor block ;z .inthe cartridge 14 .;v The block 32,18 provided with a'Dlurality of-generally radial-slots '1 in which are positionedwvanes-fl, as seen: inl lg- -ure'j4, the vanes being radially movable inwardly and outwardly within the slots having a' cylindrical externalgshape and anj'approximately oval internal'shape -against which the ends of thevanejsf 3. contact. Therotor' 32 5 provided with hollow j hubs llfwhich run in "i hich overlie the, side'ifa'ces or. the rotor and the ring 3 6, 1 The righthand flange 42 is provided harge ports 48; whichjappea'r inFigures 3. and 5.

ports: 16 communicate by "an inc1ine'dQpassage '50 w he QECM WeWeY 1 whichiextend 360 degrees .around their inner faces"at;4a3point adjacent the inner end of, the slots in'the rotor. Thegrooves 52' thus provide access connection to the space inthe slots beconnects with the discharge passage 22' by means of a"restrictedpassagil in'Figurejl. The left:

*way 56 "Witlr-a pipe cionne unn sa and'with a 'tof orpexY at a? predetermined; pressure? in the pasvin'g'a'loclrfn'ut"'64. Whnthe vaive'i l is open;

fluidJpassing therethrOughis] carried to the suciv With the ex'ception 'of the restricte d passage 54 and theparts which leadoff from the passage i 55,: thei 'pumpmay be constructed-similarly to gthatillustrated in the patent; to "Harry FJVickers, '1--i No;,-'1;989;900; to:which'reiierence i'svmade for disclosureof certain' detail features omitted" from thepresent drawing for the sake of clarity.

-. ,shown,;; The body "is provided with an arcuate A suctionpqrt-gl! communicating with a'suction pipe connection ll-andradiallyinward thereof Journalled'. bearingt i l inthe housing Thefcartr idge l4 includes a iri g mmsa 'u;

j beari'n'gs 4p, formingilpartiof thecartridgelL The bearings 40' have integralaflange portions 42 h fll lii lq j i fl nd arcuate dis-j The ports '44 communicate'fby inclined. passages l8""w'ith "the suction passageway ,l'l, while,the

neatlfthe wines The 'righthand groove 51 handgroovev fl 'co'nnects by m ans or a passagei' pilot relief valve 60f The later is spring-loaded =1: sage' ifiwhich pressure may ea justea through I the cmediunii or a 'spring-adjusting'iscrew 02 hav tion passage 18' througha duct 6 6 iormed in the vanes 34.

the pump is identical to that described in the previously mentioned Vickers patent, and oil is carried from the suction ports to the discharge ports, the vanes 34 sealing the space between therotor 32 and ring 36 at the diametrically op posite top and bottom points in Figure 3.

52 is under the full pressure oif thev pump dis"- charge since there is no flow through the restricted orifice 54 and consequently nopressure drop therethrough. This is because there is always the same number of vanes moving inwardly as there are moving outwardly at any in- .stant and the total volume of fluid in the groove 52 and the slots connected thereto remains constant. Thus, the vanes 34 are projected outwardly as they pass across the suction ports 44 inFigure 4. This is the normal pumping action oithe device.

When the delivery pressure against which the pump dischargesrises to-a value higher than that for which'valve 60 is adjusted, the valve opens, permitting liquid 'to escape from the groove 52through passage 56, valve 60 and passage'66. This causes a flow to take place through the restriction 54, and, as the flow rate increases, the pressure drop through the restriction 54 increases, and there is accordingly less pressure applied ,to the under surface of the When this tendency has progressed to the point where the'difi'erence in pressure'between that applied to the outer end of a given vane as it approaches one of the pressure ports 45 and the pressure applied to the inner end of the same vane is ajgreater diiference than the centrifugal force applied to thatfparticular vane,

*"then the vane will be forced slightly inwardly,

permitting oil to escape between the outer, face of the vane and the inner ,face of the ring 36.

In this way, high pressure oil frornrthe discharge port 46 may flow back past the end of the vanes 34 to the suction port 44. Thus, the net deliveryof the pump is reduced, and consequentlytends to reduce the pressure in the discharge passage 22 until it eventually falls to a value where the valve lio again closes, and normal action is restored.

j and the device then provides merely overload pressure-limit. protection.. In the event, how-.., ever, that it is desired to interrupt the delivery of fluid by the pump without stopping the rotation v of shaft 28, the connection 58 maybe used as a vent connectlonto unload the pump at will.

Thus, theduct 56 may be opened by removing the plug in connection 58 or it may be connected to a remotely operable on-ofl valve which, when it is opened, will connect the duct 56 to an-exhaust point, such as the oil reservoir, and instantly drop the pressure beneath the vanes to a very low value. 'Accordingly, the vanes will be pushed inwardly as they approach the. pressme port, and this acti'on'will continue until the discharge pressure has fallen to avaluejust necessary to overcome the centrifugal force tending to push the vanes outwardly.

In addition, it may be desired to vary the quantity of fluid delivered by the pump without completely unloading it. In such case, the plug may be loosened to permit leakage or the on-off valve may be so constructed or operated (e. g., a needle valve) as to variably restrict the exhaust from groove 52. Byloosening the plug or openingthisvalVe to a greater or less'extent, its resistance may be varied relative to the resistance 01' restriction 54, and consequently the pressure beneath the vanes may be regulated to become any desired percentage of the discharge pressure, and the degree of slippage of the pump is correspondingly varied.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows:

- 1'. A'rotary vane'type pump having a pump stator having a fluid working chamber having 'inlet and outlet 'ports,'a rotor'membe r mounted in the fluid working chamber, one of said members having recesses therein, alternately retractable and extendable vanes mounted in said recesses for sealing the passage offluid between the pump outlet and inlet, means forming a pressure chamber communicating with the re- I cesses, the pressure in which is effective to urge the vanes outwardly, a permanently open, restricted passage connecting the pressure chamher with the pump outlet, and a pressure responsive relief valve connected between the chambers and an exhaust point responsive to and limiting the maximum pressure in the chamber :to vary the amount. of extension of the vanes when a predetermined pressure is reached at the pump outlet to thereby vary the amount of slippage .past the vanes in a manner to maintain pump outlet pressure 'constant.

2. A single,-- self-contained, self-regulating pump unit comprising a single pump of the rotary, multiple-vane type,'a pump statofr having afluid' working chamber having inlet and outlet ports, a rotor member' mountediin the fluid -working chamber, one 01 said members having recesses therein, vanes mounted in said recesses for inward and outward movem'ent, fluid pressure means for causing movement of the vanes outwardly during a phase of pump rotation, a

pressure-responsive relief valve of small capacity with respect to the pump capacity, means for causing said relief valve to govern the outward movement of the pump vanes whereby the slippage of the pump may be purposely increased to maintain pump discharge pressure within a pregodetermined limit, and additional means governingmovement of the pump vanes by cooperation with said first means and effective to unload the pump independently of said" relief valve.

3.'A "single self-contained, self-regulating pump unit comprising asingle pump of the rotary vane type, a pump stator having a fluid working chamberhaving inlet and outlet ports, a

rotor member mounted in the fluid working chamber, one.of said members having recesses therein, vanes mounted in said recesses for inward and outward movement, a pressure chamber 'in permanently open but restricted communication with the discharge side of the pump and efiective to maintain the vanes fully projected into pumping position wherein'slippage is a minimum, and means eflective to vent said" chamber and prevent fullproiection of thevanes whereby pump slippage may be increased to substantially 100 per cent. v v 4. A rotary pump comprisng in combination a stator having a pumping chamber therein,

being pumped, said ports being spaced apart and separatedbysaid vanes in" passing through said 7 I working space, and means selectively operable to [a rotor in saidchamber and having a plurality oi. recesses and vanes rotatable therewithand vary the movement of the vanes relative to the rotor andthereby connect the inlet and outlet ports, said means including a permanently-open restricted connection between the outlet port I and said recesses and a normally-closed passage leading to an exhaust point and means-to; open said passage for at times exhausting said recesses. l

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