US2689458A - Rotary hydraulic coupling - Google Patents

Description

2 Sheets-Sheet 2 Filed may 22. 1951 v fill/dz Patented Sept. 21, 1954 u En: PAT ENF @FFIQE mesa-15's" ROTARY HYDRAULIC COUPLING: V Cliai'ls'TerrsWeymann, Paris, Fiance Application May 22; 1951;Serial Now227563 Claims 1mor1tv, appiiiiation France May 25, 1950 The-present invention relates to tlie Fottingeitype of 7 hydraulic power transmitter or fluidcon pling in which driving"and diiven'meni-bers are' catch provided with anannular series of vanes; blades-or passages; and the' two'members ai'e -so designed and so juxtap'osed that the impellingliquid whiletravelling" the operating circuit defined b'y said blads or passages *eflects thero tation' 01 the driven member in: response to the rotation of the driving member;

Couplings of= this ityperoffer manwadvantages: as a: very "high deg re'e of I startin gti'smooth ness; this? operation. being effected; without any special p'edal, undQ'ai-Lthe Imerei controls of itheinor mal acceleratlozt oi'wthe engine, .aLhigh'er degree: or saiety against cutting out'ioflthe'engineysilent operationgzab'sence: of wear and' sown. These couplings; h0W8V81,'. have" the drawback in that it is: diflicult to oldtain' at the same time the de shied disengagem'ent'of thencotpli-ng; as'stheren gine isth'rottled down; and'the'total power trans mission with aminimnm slippag'e betwe'emthe: driving. and-driven shafts as the-engine is spe'eded': upa i 1 t-yis an objectwf the inventionto provide" a hydraulic couplingvofthe type describedwhieh is capable of ensuring both a:- complete dec1utching;- as theengine isth'rottled down and' a substan tialliz ifistantan'eous reolutc'liing, as the engine is speededup'agam;

Acdordingto the" presentiiiveiitioii. there: is"

provideda hydiaulic coupling comprising a pump tion"; when the speedf'ofthe"driving'shaftreacfies a predeterminedvalue,theoutlet port" of ports are" closed and the" above mentioned feeding rne'ans" ensure a proper filling of the device? Wheelr'otatin'gr' with adrlviiig'shait, turbine wheel secured= to a driven shaft-l casing" fiired to said pumwwh'el foi rotation therewith} and enclosing sald' turbine: wheel means di'iven by" said driving shafif fon' continuously suppljiing Hquid-iuuder ressurerinto saidicasi lea'stf one liquidaoutletvport in the'iperiplietieall wazil of -s'aid' casmg;.overflow means :forvcondueting said iq uidIzfi-omi the :interior or said' -casihigl to said out let: pormsaids overflow? means determining tne" highest level or a? liquid volumeconstantly re tamedin said casingwheri saiddiitlet -fioh 5- open, and icentriiugallt *operated vaivemeans as minted witlilsaid 'outlet 'port for preventimg liwutdoverflowingt said level from? discha ging through said? outletport when said calsingi r0 tdtesabove avpredetemninectspeed;

n The :liquid: may! be supplied fromia sumwcoiistitutedby the bottom oct thaelhousing o't th'e 'de= viceiath'e 1 liquidi supplyingi means beingadapted tb recycl'elcontinuouslyithe llqiiid evacil'ated ffbfii the casing into saidvsu'inpz nWiththmarrangementqiaeordingfitdthe inven- Wl'ienthe engine slowsdowri under agiven value;- the strength of the spring tending to openeaoh valvebecomes higher than the-combined action of the-centrifugal force -and liquid pressure act'- ing inthe opposite direction, and* causes the openingof the 'outlet port" controlled by said valve; so that the" above mentioned predetermined'amountof the liquid is expelled under-the action of centrifugal force through L said outlet port thus" reducing the} maximum torque which can beti'ansmittedmy th'ecoupling;

In a preferred embodiment of the invention; the overflow means for conducting liquid; tothe outlet-port} is constitn-tdby a passage extendmy ream-11y ffom =the interior of the casing w an outlet port in the periphery of' thecasingg'said part being controlled bysaid valve.

This arrangement provides three advantages viz. the valve is located at a point where itsiop eratiiig condition's are optimum, the evacuationof the-liquid; sinoe it takes placethroug ai radi'al passage, is rapidly eifectedmy oenti iiuigal fi 'jtoe; and the casingl'cannot be emptied below a certain 1eve1 determined byii'the :position of the 'n"-= ner end of saidrrpassage 'soithat thez-re-fillin gr-of the casingg when the engine ris speeded up iagain, takespla'ce rapidly; which ensures aisubstaritially instantarieou's' reclutching;

For" each outlet 'ort there maybe provided a; secondary: 'outvi ardlywpenin g valve mounted iri series-'6 with the above: mentioned valve means (hereafter also called the primary-valve) either upstream or downstream with respecmo the same; said Secol idal-"y' valve being Y adapted 110- be brought by slight c'entrifugal force into its open-- ing position; while it is' u'tge'd into itsclosing position an opposing spring sii-ita'bly" Callbrated; so than said secondary" valve remains closed under"- a relatiwiely' slow predetermined speed -lower thanthe closing and opening speeds" of the niain valve."

With this arrangement} the secondiiy valveis awaysepned before the primary valveis' cldse'df When" due to deceleration; the primary valve" opens-, the secondary valve' remains also opened" closes At "and-below saidlast mentioned speed an'd even' when the -engine is completely stopped;

said scondary 'valire always remains closed,

Additional feeding means actuated from the 3 driven shaft may be provided for feeding the casing when the driven shaft is rotating and the driving shaft is at rest.

Bleed means constituted by outlets may be provided in the pump wheel in the vicinity of the casing axis and controlled by spring loaded nonreturn valves opening outwardly under a predetermined pressure, while preventing the liquid from escaping at pressures below said pressure.

Since the casing can never be emptied, any torque generated by the driven shaft will be transmitted to the driving shaft thereby starting or assisting in starting the engine. Said engine then transmits to the driving shaft a speed sufficient to cause the opening of the secondary valve,

thus re-establishing the normal running conditions.

The invention is illustrated by way of example in the accompanying drawings in which:

Fig. 1 is an axial section of a hydraulic coupling according to one embodiment of the invention.

Fig. 2 is a section along line 2-2 of Fig. 1.

Fig. 3 is a view similar to Fig. lof another embodiment comprising two valves for each outlet, the secondary valve being located downstream of the primary valve.

Fig. 4 is a detail view of the primary and secondary valves in the position corresponding to a speed comprised within the secondary valve opening speed and the primary valve closing speed.

Fig. 5 is a part view of said valves in the normal running condition, i. e. at a speed higher than the closing speed of the primary valve.

Fig. 6 shows an alternative arrangement in which the valves are circumferentially spaced in order to provide a reduction of the radial thickness of the casing.

Fig. 7 shows an alternative embodiment in which the bleed means are constituted by spring loaded ball valves.

Fig. 8 is a modification of Fig. 3 in which the secondary valve is located upstream of the primary valve.

Fig. 9 shows an alternative construction of the embodiment of Fig. 6 in which the valves are circumferentiallyspaced.

Referring to the drawings, there is shown at I, the housing of a hydraulic coupling, at 2 thedriving shaft and at 3 the driven shaft.

On driving shaft 2 is fixed for.rotation with said shaft a casing 4 carrying a driving centrifugal pump 5 which projects, when shaft 2 rotates, a strong oil stream onto the blades of a receiving turbine 6 fixed on the driven shaft 3 for rotation therewith. In the example shown, there are provided, in the outer periphery of easing 4, a number of liquid outlet ports 1 controlled by valves 8 adapted to be brought by centrifugal force into their closing position, a spring 9 urging said valves towards the opening position. The outlet ports I communicate with the working chamber of the coupling through overflow means which, in the example shown, are constituted by a radial duct lb opening into said working chamber at a point thereof lying nearer to the axis of the coupling than the point of said chamber remotest from said axis, so as to determine a highest level, indicated by line 1a, of constantlyretained liquid, as hereinafter more fully explained. There is shown at Ill a rotary pump, the

. rotor of which is rotated from shaft 2, said pump sucking through a pipe H oil contained in the sump 12. The oil discharged from said pump flows, as indicated by arrows in Fig. 1, through ducts I5 provided in the surface of shaft 3 and .4 passages l4 provided in the hub of the turbine wheel -6, and is directed towards the working space of the coupling comprised between the vanes of members 5 and 6. A portion of said oil is by-passed through bearings l3, which improves their lubrication.

It will be understood that when the driving shaft 2 rotates faster, the valves 8 are seated under the action of centrifugal force, so that casing 4 is closed. When the speed of shaft 2 slows down to less than a predetermined value, springs 9 open valves 8 by overcoming at the same time, the centrifugal force and oil pressure exerted upon the valvesurface. Below said speed,

the oil amount comprised within the circumferential level indicated by line Ia and corresponding to the inner openings of the radially extending overflow ducts lb leading to the outlet ports 1 is expelled through these outlet ports and a sufiicient declutching takes place instantaneously. Once this declutching is effected, the volume of oil retained within casing 4 remains substantially constant, the evacuation rate of the valve being materially higher than the discharge rate of pump 10, so that although the latter is still driven by shaft 2, the oil level is in no way affected. Thus, as soon as the engine is speeded up again, while valves 8 are closed under the action of centrifugal force, the clutching is effected almost instantaneously. It is to be understood that when the casing 4 rotates at a predetermined speed, the spring force should be sufficient to open the valves not only against centrifugal force but also against the oil pressure exerted upon the outer surface of valves 8.

In the embodiment shown in Fig. 3 a secondary valve I1 is provided downstream of the primary valve 8, these two valves being interconnected through passages l6 and 20; said secondary valve 11 is urged towards its seat by a spring IS. The two valves thus open in opposite directions. As shown in Fig. 8, the secondary valve ll may be arranged upstream of the primary valve 8.

An additional rotary pump 2! operated from the driven shaft 3 discharges the liquid sucked through a pipe 22 from sump l2'into the axial duct '23 and radial ducts 24 to feed the working space of the coupling in the same manneras the above described pump I0. Bleed holes 25 located in the pump wheel 5 in the vicinity of the casing aXis and intended to evacuate the liquid.

excess, are provided with non-return valves 26 maintained in closed position by springs 21;. As shown in Fig. '7, these non-return valves may consist of balls 26 loaded by calibrated springs 21.;

This device operates as follows: As described with reference to Figs. 1 and 2, when the engine is normally running, the primary valve 8 urged by a centrifugal force capable of overcoming the strength of spring!) is closed. The secondary valve or valves I! are opened for the same reason. The casing fills up and the coupling transmits a normal torque. The. ex. cess of liquid is evacuated through bleed holes 25, since the non-return valves 26 are opened under the action of the discharge pressure of pump I0. In the case when said non-return valves are constituted by balls, the objectionable action of centrifugal force liable to prevent said balls from tightly seating is eliminated by guiding said balls in bores provided with longitudinal grooves capable of ensuring the evacuation of the liquid as shown in Fig. '7.

When the engine is throttled down, the primary valve 8 opens when the speed falls below a predetermined value due to the resulting decrease if the centrifugal force; the liquid is expelled out through passages 16 and 20 and through the secondary valve I! which is still open, until the inner level of the liquid, due to the decrease in the centrifugal force, reaches the level indicated by line 1a. Then, the driven shaft is no longer materially driven. If the speed further slows down, the secondary valves 11 close, due to the further decrease of the centrifugal forces, whereupon they remain closed until the device completely stops. During this time, the device is partly filled again, but since, in the meantime, the rotation speed varies between a very low value and zero, this causes no material rotation of the driven shaft. Since the pressure of liquid within casing 4 decreases with decreasing rate of supply, the non-return valves 26 are closed by their springs 21 to prevent the liquid from escaping through the passages 25.

Thus, in the case when the driving shaft is to be started from an external force applied upon the vehicle, i, e. from driven shaft 3, the amount of liquid stored in the casing may be suflicient to allow the transmission of a torque from the driven shaft to the driving shaft even with a high degree of slip between said two shafts. However, in case of comparatively high resisting torques, the additional pump 2| operated by the driven shaft will supply a sufllcient quantity of liquid, the valves 11 remaining closed, to decrease the slip between the driving and driven shafts and cause the engine to be started. As soon as the engine runs, the operation phases described with reference to Figs. 1 and 2, take place normally.

In the embodiments shown in Figs. 6 and 9, the secondary valve I1 is located side by side with respect to the primary valve 8, so as to reduce the radial thickness of the casing'wall. The operation of the device is unchanged, the passage 16 interconnecting the two valves extending circumferentially.

It will be understood that the invention is in no way limited to the type of valves described and that the same, instead of being of the axial type shown may be made in any other shape such as lever-controlled tilting valves. Moreover, said valves may be located in other zones of the easing. The above-mentioned non-return valves may be also located in any desired point, provided that they open outwardly of the casing.

What I claim is:

1. A hydraulic coupling comprising a .pump wheel rotating with a driving shaft, a turbine wheel secured to a driven shaft, a casing fixed to said pump wheel for rotation therewith and enclosing said turbine wheel to thereby define a work chamber, means driven by said driving shaft for continuously supplying liquid under pressure into said casing, a liquid outlet port in the peripherical wall of said casing, overflow means within said casing establishing a communication between said outlet port and a point of said work chamber nearer to the axis of the coupling than the point of said chamber remotest from said axis, an inwardly opening check valv arranged to cooperate with said outlet port to close the same by centrifugal force when said casing rotates above a predetermined speed, and resilient means adapted to maintain said valve in opening position as long as said casing has not attained said predetermined rotational speed.

2. A hydraulic coupling comprising a pump wheel rotating with a driving shaft, a turbine wheel secured to a driven shaft, a casing fixed to said pump wheel for rotation therewith and enclosing said turbine wheel to thereby define a work chamber, a rotary pump driven by said driving shaft for continuously supplying liquid under pressure into said casing, at least one radial liquid outlet duct within said casing and extending from the peripherical wall thereof to a point of said work chamber nearer to the axis of the coupling than the point of said chamber remotest from said axis, and a centrifugally operated springloaded valve mounted in said duct to close the same when said casing rotates above a predetermined rotational speed.

3. A hydraulic coupling according to claim 2, in which secondary outwardly opening valve means are disposed in series with said centrifugally operated or primary valve means, said secondary valve means being urged by spring means towards the closing position and by centrifugal force towards the opening position, said spring means being so calibrated as to bring said secondary valve means into the closing position at a rotational speed lower than the opening or closing speeds of said primary valve means.

References Cited in the file of this patent UNITED STATES PATENTS

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