AU619487B2

AU619487B2 - Space-saving multiple-disc wet brake in the wheel hub of running gears with epicyclic gear

Info

Publication number: AU619487B2
Application number: AU22840/88A
Authority: AU
Inventors: Andor Opitz; Gabor Szalai
Original assignee: Magyar Vagon es Gepgyar
Current assignee: Magyar Vagon es Gepgyar
Priority date: 1987-09-28
Filing date: 1988-09-26
Publication date: 1992-01-30
Anticipated expiration: 2008-09-26
Also published as: HUT53319A; CZ278700B6; DE3832649C2; DE3832649A1; AU2284088A; FR2621089B1; HU203704B; IT1227227B; IT8822088A0; FR2621089A1; CS8806420A2; RU1838687C

Description

p Kr 61 9487 S F Ref: 72366 ~FORM COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: Class Int Class Complete Specification Lodged: Accepted: Published: Priority: Related Art: Name and Address of Applicant: Magyar Vagon- 4s Ge'pgyar Gyor 9002

HUNGARY

0800 0 0 go 0040 0 0090 o 00 08 0 0 00 00 0 0 00 04 09 9 00 0 00 0.

0 0 0 00 00 00 0 00 Address for Service: Spruson Ferguson, Patent Attorneys Level 33 St Martins Tower, 31 Market Street Sydney, New South Wales, 2000, Australia Complete Specification for the invention entitled: Space-Saving Multiple-Disc Wet Brake Running Gears with Epicyclic Gear in the Wheel Hub of The following statement is a full description 0*:best method of performing it known to me/us of this invention, including the 0 84 4 4 t C e 4 C 8 4 CC 5845/3 Udism. applk$.a1LuILJJ IVCIV1IU LU 111 Faiar "F- Declaration was/were the first application(s) made in a Convention country in respect of the invention the subject of the application. l Declared at Gyor this 4 a o ?rPGY sFP4 To: The Commissioner of Patents Signature of Declarant(s) 1/81 II I I i p i Ai B, i1 i A S TRACT The invention relates to a wheel hub consisting of two halves and interconnected with a screwed connection, the outer space of which contains one or more epicyclic gears driving the wheel hub. In the inner space between the rolling bearings supporting said wheel hub, in the oil space of the wheel hub there is a multiple-disc brake for braking said wheel hub arranged..

In the centreline of the wheel hub there is a stub axle which is connected with the extension of the torque support of the epicyclic gears driving the wheel hub so that the outer ribs of the stub axle provided with a bore should be able to transmit the torque.

The outer bearing of the wheel is bearing up against the shoulder of the torque support, while the outer ring is in the outer half of the divided wheel hub.

The inner bearing of the wheel can be arranged on the stub axle or at the end of the extensions of the torque 0• .support. The outer ring of the inner bearing and. the sealing ring closing the oil-space are arranged in the *0 0 o inner half of the wheel hub.

O Between the two bearings of the wheel the lamella bundle comprising the stationary lamellae and the rotary lamellae, the compressive disc, the support disc as well as the hydraulic brake cylinder actuating the brake, I the brake piston are arranged.

I| When operating the brake mechanism, the brake-hydraulic Sliquid flowing under a high pressure in the hydraulic VI 0 bores of the stub axle (and in the extension of the i

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i 1 torque support) penetrates between the brake cylinder and the brake piston an-,d after having compressed the bundle of lamella, it presses the bundle of the. flange of the wheel hub h~aviLng been formed for thi~s purpose* or the bundle is pressed to the shoulder of the inner ring of one of the bearings of the wheel with the intervention of the compression disc and the support disc, respectively.

The outer ribs of the rotary lamnellae engage with the inner mantle of the wheel hub loosely but suitably for transmitting the torque, while the lamellae with the inner ribs are engaged with the outer ribs of the extension of the torque support loosely but suitably for torque transmission.

The sun gear of the epicyclic geax/s/ is driven through the stub axle provided with bores, while the driving member of the epicyclic gear/s/ is connected, to the outer half of the wheel hub so as to be able to tran~smit the torque.

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i 7, SPACE-SAVING MULTIPLE-DISC WET BRAKE IN THE WHEEL HUB OF RUrNING GEARS WITH FPICYCLIC GEAR wet brake arranged in the wheel hub of running gears driven with epicyclic gear/s/, with which a bundle of °o lamellae (discs) consisting of the rotary lamellae 0" connected to the inner ribs of the mantle of the wheel O-o: hub having been screwed, together from two halves and, a os alternatively comprising the stationary lamellae connected bundle of lamellae for braking the wheel hub, a brake Spiston, a pressure disc and a supporting disc forming T .i a system are arranged between the outer and inner bearings supporting said wheel hub, in the inner oil space of the wheel hub.

A 41 anla dss ossigo h oaylmla cnetdt teinrrbtftemateo h he! ub avin ben scewe togthe fro tw hales nd 2 With vehicles, machines used, in the building industry, mines which are working under muddy and dirty conditions it is considered as advantageous, if the brake construction is working in a closed and insulated space.

These valuable productive machines must work continuously, every interrupted, working hour involves considerable losses for the user. Reducing service requirements to the minimal level is of utmost importance. For this reason recently multiple-disc brakes arranged in the inner space of the running gears the so-called wet brakes became increasingly popular. In respect to fundamental principles up to now two solutions used, to be applied.

With one of the solutions the brake construction brakes the wheel hub directly and, it is built-in therein, where the traditional drum brake or an external dry disc brake used to be arranged., US-PS 4 173 269, US-PS 4 358 000 and GB-PS 1 504 073 and GB-PS 2 085 100 disclose these types.

In the other case the brake construction brakes the running-in member (sun gear or differential shaft) of :the epicyclic gear/s/ and may be arranged. in the wheel *a hub next to the epicyclic gear/s/ or between the bridgehouse and the stub axle or it may be arranged next to the 0 o0 main drive. US-PS 4 037 694, US-PS 3 754 625 and GB-PS 2 130 666 specify said solutions, i.e. this principle of construction used to be applied in the running gears ZF, SCarraro etc.

All the solutions have their advantageous and disadvantageous characteristics, these are to be surveyed, in order to be able to follow the train of thoughts leading to Sthe recognition resulting in the invention.

-3- Generally, constructions belonging to the first solution have been used, in running gears with larger capacities, while the space staying at disposal is larger, accordingly, more heat can be absorbed.. An advantageous contribution lies in that as wheel hub is braked directly, in lack of transmission more pairs of lamellae (discs) are required.. A very important advantage lies in that it is absolutely independent of force transmission of the running gear, as a consequence, elements of the epicyclic gear/s/ transmitting the drive are not at all influenced, by the brake construction, that means that an ideal system of toothed gears can be planned.. Due to the miutual independence brake construction can be planned, ideally too in compliance with the selected, solution. A further advantage of this solution lies in that spatially it can be separated from the oil-space of the running gear, so by using a special coolant thermal capacity and safety of operation can be increased.. High-pressure hydraulic liquid, can be led, to the brake in a more direct way, a better sealing can be achieved.. With these constructions it can be easily realized.

o *that operative brakes should be completed with the function of a fixing brake storing spring force.

o op Disadvantages of the first solution result from the arrangement of the brake construction. Due to the arrangement behind, the wheel hub, mounting and servicing become possible only if epicyclic gear/s/, bearings of the wheel hub are disassembled,, dismounted. Assembly in course of *production, resp. re-assembly after servicing become most complicated and labour intensive, as due to the d.isplacement of the lamellae meeting with the engaging ribs becomes possibly only by using special mounting sleeves or lamellae (with guide lugs. The solution according to US-PS 4 173 269 S, is aimed at the elimination of said. problem.

tt II t 1 -4- A further significant drawback of the wet brake constructions of the aforementioned, type lies ir, that they d.o not enable the development of steered, running gears, as arrangement of the ball- and, socket joint, of the ball- and, socket joint receiving casing and. steering construction cannot be solved, structurally. According to our best knowled.ge steered running gear containing such a brake construction has not been developed up to now.

A further disadvantageous feature of said, construction lies in that the construction lying behind, the wheel hub is arranged in a separate casing; accordingly, more dividing planes, screwed connections, ribs and. sealings are required. involving consid.erable extra expenses.

In brake constructions having been built-up in the second principal system in proportion with the transmission of the epicyclic gear/s/ less braking torque, accordingly a smaller number of disc-pairs are required., in comparison to the constructions, with which wheel hubs are directly braked. Reduced. number of lamellae (discs) is considered, °as advantageous in respect to expenses, as a matter of fact up to the limit, till specific energy load. of lamellae surfaces and, quantity of arising heat are still tolerable and, do not shorten useful life. In case if bundle of lamellae and the actuating system of the brake cylinder and brake piston are arranged, immediately next to the epicyclic gear/s/, the advantage of said. solutions will lie in easy assembly and servicing, as bearing of the wheel need, not to be disassembled,, that means that an eventual repair can be carried out without disassembling the wheels of the vehicle. The illogical feature, however, lies in, that easy serviceability is mentioned in connection with J rL+ ia construction which /namely the wet brake construction/ j was developed just in consideration of service-freeness.

i I 5 Reduced number of lamella-pairs requires a shorter stroke t of the brake-piston, proportionally therewith quantity of the high-pressure hydraulic liquid, can be also reduced,, reaction of the brake will be quicker. The most unfavourable characteristic of the wet brakes having been built-up according to the second, principal system lies in that epicyclic gears, resp. bundle of lamellae arranged, next to it and. actuating hydraulics are mutually disturbing one another.

With the known solutions sun gear or the half-axle is connected. directly or indirectly to the rotating lamellae, while stationary reacting lamellae are connected, also directly or indirectly to the gear rim. It is a generally known fact that for an epicyclic gear it is the most advantageous if both the sun gear and. the gear rim are self-aligning in order to be able to equalize the transmitted loads resulting from inaccuracies of manufacturing, tooth forces and d.eformations. At the same time, in respect to the brake it is considered as most advantageous if both stationary and rotating lamellae are correctly guided to eliminate vibration 9. and noise.

S It is quite obvious that these counter-acting requirements 00 cannot be met, that means that required, compromises exert a negative influence on the structural units, each.

A solution is also known e.g. with the Carraro running gears with which,in consideration of the above mentioned, the brake used to be installed between the bridge-house and, the stub axle, thus reducing disad.vantageous interaction, however, this arrangement makes assembly and servicing •extremely difficult.

A further drawback of this construction lies in, in so far ctr as, since transmission of the epicyclic gear/s/ is ased Sfor reducing the required, braking torque, number of the lamellae used, to be determined, accord.ing to said, torque, *1I- resulting in a high load of energy on the surface of the lamellae. It goes without saying that with identical requirements in respect to braking, when less lamellae are used,, loading of lamellae increases, simultaneously useful life will be shorter. Accordingly, it seems to be more advantageous if quantity of lamellae is determined by limiting energy load acting on the surface of the lamellae.

A further disadvantageous feature of said, construction lies in that the space staying at disposal for arranging the bearings supporting the wheel is less, so proper useful life can be obtained with more expensive bearings belonging to higher series only. It is also considered d.isad.vantageous that operative safety decreases as with broken epicyclic gear or half-axle the vehicle becomes uncontrollable: occurence could be prevented only with the expensive reinforcement of the structural elements.

Thereafter, the requirements can be determinded., which when met enable the application of wet brake con- 0a* structions in the wheel hub of running gears driven with "o epicyclic gears in a way approaching id.eal conditions.

o o These requirements are as follows: o 0 requirement of servicing is to be reduced to the possibly minimal level; this can be achieved, by reducing the energy load on the lamellae surfaces with simultaneous increase of the number of lamellae; that means that it is considered as expedient to brake the wheel hub without transmission, i.e. directly.

o o Defined separation of the gear elements of force transmission and the elements of the brake construction with Sethe purpose that both structural units could be formed "cL ideally, without compromises, in compliance with their own function.

-7- Accurate guide as well as of the rotary as the stationary lamellae on a fixed structural element or on an element supported In bearings, with the purpose to reduce vibration and noise to a minimal level in course of braking and free-running as well; Bundle of lamellae and the actuating hydraulic dnit should be arranged so as not to restrict the formation of other structural elements, in a space which yields complete protection against external contaminations; In compliance with given possibilities, easy assembly should be enabled by using a small number of simple elements. I According to the present invention there Is disclosed a wet brake i structure contained In a wheel hub, said wheel hub driven by an epicyclic gear train, comprising: a lamella-type brake, further comprising alternating stationary 0o0: 15 brake lamellae and rotating brake lamellae, S. a means for compressing the brake lamellae, further comprising a oOO hydraulic brake cylinder, a brake piston, a compression disk and a S° support disk, and o° an inner and an outer wheel bearing, wherein there is disclosed: rotating brake lamellae joined to the inner casing of the wheel 0o: hub; and stationary brake lamellae joined to a torque support so arranged to be driven by the epicycllc gear train, the lamella brake being mounted axially disposed between the outer wheel bearing and the inner wheel bearing within a volume of space to be filled with a suitable lubricant, i the epicyclic gear being mounted on the opposite side of the outer j bearing from the brake lamellae and inner wheel bearing in an axial direction,

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"1 the epicyclic gear and the lamella brake being separated within the wheel hub by a rib joined to the inner casing of the wheel hub, wherein the outer wheel bearing abuts the rib in the radial direction.

The brake construction, the arrangement thereof and structural I solution meeting the requirements will be explained in detail with reference to the accompanying drawings, wherein: Figure 1 illustrates a wheel hub driven with single-row epicyclic gear, ST 63w :li

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8 Figure 2 illustrates a wheel hub driven with a doublerow epicyclic gear with branched capacity.

On both figures components performing the same functions are indicated with the same reference number. Certain structural part-solutions in dependence of the scope of application of the wheel hub and concrete dimensions deviate from each other in the two constructions, however, these differences are in full compliance with the essence of the solution according to the invention; with these components reference numbers are differentiated with the index in figure 1 and with ind.ex in figure 2.

To achieve the arrangement of the multiple-disc brake according to the invention the wheel hub is composed of two halves 1, 2 which are clamped either by the wheelscrews 3a or with a separate screwed. connection. The stub axle 4 with the bore lies in the centreline of the wheel hub 1, 2, the stub axle is connected with ribs to the torque support 5a, 5b of the epicyclic gear/s/ so as to be able to transmit the torque, while fitting of the stub axle and the torque support is assured. with the guide ring 6.

The inner ring of the outer bearing 7 of the wheel hub is bearing up against the beginning of the extension of the torque support. The outer ring is supported in the larger half 1 of the wheel hub, while the outer ring of the inner bearing 8 of the wheel hub issupported by the smaller half 2 of the wheel hub. The inner ring lies on the stub, axle 4 or the extension 5b of the torque support.

Between the bearings 7, 8 of the wheel hub the elements of the brake construction are arranged,: the brake cylinder 9a, 9b, the brake piston 10a, 10b, the stationary brake-lamellae 11 with the inner ribs, the rotary lamellae 12 with the it Sa *goo s a t 1, C" C 0cc *000o 00 0 0 00 A~ 08 we CI. as *I t 4 1 I i, i4 r: i i 1i i B ij ;r 1: :r

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9 outer ribs, the pressure disc 13 and. the supporting disc 14a, 14b.

When the brake is operated, the brake-hydraulic liquid, flowing in the bores of the stub axle 4 and, the extension of the torque-support 5 penetrates between the brakecylinder 9a; 9b and the brake piston lOa, lOb, the latter one compresses the bundle of lamellae consisting alternatively of the rotary lamellae 12 and. the stationary lamellae 11 by means of the compression disc 13 and presses said. bundle with the intervention of the support disc 14a, 14b either to the shoulder of the outer bearing 7 of the wheel hub, or to the outer hilf 1 of the wheel hub.

Lamellae 11 with the inner ribs are connected loosely but suitably for the transmission of torque to the outer ribs of the extension of the torque support 5a, At the same time the lamellae 12 with the outer ribs are connected similarly loosely but suitably for the transmission of torque expediently with the intervention of ribs, eventually pins or catches to the outer half 1 of the wheel hub.

0 0 °o 0 In order to avoid mutual friction between the lamellae 11, BO 4 6 'o 12 in standstill of the brake, return springs (compression springs) may be built-in. Anchoring of the return /com- S, pressions/springs and axial release of the bundle of lamellae may be carried, out expediently with the intervention S, of the screws 16a, 16b and the compression disc 13.

Epicyclic gear/s/ of the wheel hub is driven with the intervention of the half-axle 17 extending through the i I stub axle with the bore by the sun gear 17a, 17b forming a monolithic unit therewith. Drive is forwarded by the 3 known elements 18a, 18b of the epicyclic gear known in them- ~1 L 10 selves, a detailed. description thereof is considered as superfluous. Stationary elements 19a, 19b of the epicyclic gear/s/ are connected, to the torque support so as to be able to transmit the torque eventually it may form an integer part thereof. Driving elements of the epicyclic gear/s/ is (are) connected, to the outer half 1 of the wheel hub so as to be able to transmit the torque, e.g. with a screwed connection 21.

In course of assembly, the outer half 1 of the wheel hub, the torque support 5a, 5b of the epicyclic gear/s/, as well as the outer bearing 7 of the wheel hub are to be assembled,, thereafter support disc, lamellae with the outer resp. inner ribs are to be installed alternatively.

Easy arrangement of the lamellae is promoted. by the ribbed.

extension of the torque support extending between the two bearings of the wheel. The actuating unit consisting of the brake cylinder, the brake piston, the compression disc, the return springs and the screws which can be assembled, ooo. separately is to be installed after the bundle of lamellae.

o1o. Thereafter, with the inner half 2 of the wheel hub contain- C"c ing the sealing ring 22 insulating the inner bearing of a 00 S* 0u the wheel and. the inner space of the wheel hub and. the screw- 0 ed joint 3a, 3b we close the wheel hub and, after having arranged the complete pre-assembled. unit onto the stub axle, bearing clearance is set by means of the nut 23 on the axle-end and. we fix it with the counternut 24a.

t C If dimensional and. space conditions make it possible, it seems to be expedient in compliance with the solution according to figure 2 to lengthen the extension of the torque support 5b to such an extent that the hydraulic unit actuating the brake, the inner bearing 8 of the wheel C and. the threaded. shouldered, ring-bearing nut could be arranged, on the extension. In this way correct adjustment *1 I I s unit on the ?Lub-uxiu.

The compressive force uxerted by the high-pressure hyd.raulic actuating unit sealed by the hydraulic rings 26, 27 is taken up axially by the support disc. This force does not load, the outer bearing 7 of the wheel, if the support disc 14a is pressing the inner ring of said bearing, at the same time, in accordance with figure 2, if the support d.isc 14b loads the frontal surface of the half 1 of the wheel hub, the forces are loading the outer bearing 7 of the wheel too. Functionally both solutions meet the requirement, selection of the proper construction is to be decided in accordance with concrete local conditions and loadability of the bearings of the wheels used..

When studying the figures, advantageous features of the wet brake construction according to the invention become obvious: brake construction is arranged, between the bearings of the wheels, in a dead space not having been utilized.

up to now, in the inner oil-space and, brakes the wheel hub. It becomes possible to select practically the total surface of the lamellae id.eally, as their diameter is restricted but by the minimally needed wall-thickness of the casting of the wheel hub, their number may be optional in the space between the bearings of the wheel.

As a consequence, to lessen the energy load. of the lamella-surfaces it becomes possible to install a higher o number of lamellae with a lower friction coefficient and at lower expenses. Said. peoularity of the construction prolongates useful life in a most favourable way.

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5845/3 i 12 Elements of force transmission and, the brake construction are completely separated, function of the single units and structural formation being in best compliance with funhtion can be estsablised witihout distu'bing interactioqns. In such a manner it can be stated that epicyclic gear/s/ may be in full compliance with the epicyclic gear/s/ of a wheel-hub drive without a wet brake construction, that means that the brake construction according to the invention could be formed expediently in the same way even if it were built-in into a wheel hub without epicyclic gear/s/. That means plactically that any main unit (brake construction, epicyclic gear/s/) respectively, can be built-in resp. neglected without influencing the other one.

Lamellae can be guided perfectly. Rotary lamellae are connected. to the wheel hub running in bearings, while stationary lamellae are connected to the fixed torque support of the epicyclic gears. In such a manner operation Elements of the brake construction are arranged in a .o d.ead.space not having been utilized up to now, namely o. in the inner oil-space of the wheel hub. Aciord ingly, searching for a place to the debit of any other unit becomes superfluous.

SIn such a manner the brake construction according to the invention does not restrict possible formation of the S nthepicyclic gear/s/ or bearings of the wheel.

Examining assembly from a different point of view, the brake construction accordi ng to the invention does not require a special brake support, a separate divided, casing o 1 1 i 1 s~ i:i, r:: g-i ri~~l i 13 surrounding the brake mechanism, neither receiving elements, nor sealings are needed., still it is arranged. in a well insulated way.

Construction of the wet brake mechanism according to the invention is simple, it contains a minimal number of components, manufacturing technologies d.o not require special processes being different from the traditional ones. Simple construction affects advantageously safe operation.

Summing up what has been said, it can be stated that the brake mechanism according to the invention contains new and. progressive solutions, in the mechanism thus obtained.

the construction is in a good. compliance with the requirements to be met by the function.

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Claims

14- The claims defining the invention are as follows: I. A wet brake structure contained In a wheel hub, said wheel hub driven by an eplcyclic gear train, comprising: a lamella-type brake, further comprising alternating stationary brake lamellae and rotating brake lamellae, a means for compressing the brake lamellae, further comprising a hydraulic brake cylinder, a brake piston, a compression disk and a support disk, and an inner and an outer wheel bearing, wherein there is disclosed: rotating brake lamellae joined to the inner casing of the wheel hub; and stationary brake lamellae joined to a torque support so arranged to Sbe driven by the eplcyclic gear train, the lamella brake being mounted axially disposed between the outer wheel bearing and the inner wheel bearing within a volume of space to be :o filled with a suitable lubricant, i :0 the eplcyclic gear being mounted on the opposite side of the outer bearing from the brake lamellae and inner wheel bearing in an axial uI direction, |dr0 vthe epicycllc gear and the lamella brake being separated within the wheel hub by a rib joined to the inner casing of the wheel hub, wherein the outer wheel bearing abuts the rib in the radial direction. 2. The wet brake structure according to claim I, wherein there is disclosed a wheel hub composed of two casing components connected by i screws, the outer casing component comprising the epicyclic gear serving to drive the wheel hub, and the outer race of the outer wheel bearing, whereas the inner casing component comprises the outer race of the inner wheel bearing and a sealing ring, sealing the volume to be filled with a suitable lubricant, and the outer rotating lamellae are connected to the °ribs of the inner casing of the wheel hub length between the outer race of the outer wheel bearing and the outer race of the inner wheel bearing. 3. The wet brake structure according to claims l and 2, wherein it is disclosed that along the centre line of the wheel hub there is mounted a stub axle with a central bore, with an extension of the torque support of the epicyclic gear train driving the wheel hub via a splined connection with the stub axle, wherein the inner race of the outer wheel bearing abuts a shoulder of the extension, and the stationary j o A/1663w ribs ri il of the nner casing;. of-. the- whee hub ength:: betwee th race inner lamellae of the wet brake structure are connected to a series of outer ribs positioned on a portion of the torque support extending from the outer bearing toward the inner bearing. 4. The wet brake structure according to claim 3, wherein the extension of the torque support of the epicyclic gear train driving the wheel hub is lengthened in such a way that there is provision to mount an actuating system composed of a brake cylinder axially compressing the lamella, a brake piston, a compression disk, and a support disk; the inner wheel bearing; and, furthermore, by means of a thread, an annular shoulder adjusting the bias of the wheel bearings. The wet brake structure according to any one of claims 1 to 4, wherein the support disk, which absorbs the axial compression force of the system due to the actuating system abuts the annular shoulder of the a0 a inner race of the outer casing of the wheel hub. 6. The wet brake structure according to any one of claims 1 to 4, S^wherein the support disk, which absorbs the axial compression force of the actuating system abuts an inner flange of the outer casing of the wheel hub. 7. A wet brake structure substantially as hereinbefore described with reference to either Fig. 1 or Fig. 2. whee hub s engDATED this FIFTEENTH day of OCTOBER 1991 009a0 o° Magyar Vagon- es Gepgyar Patent Attorneys for the Applicant SPRUSON FERGUSON with reference to either F 1 or Fig. 2 i I 1 1 6 "Il I