SE1550725A1 - Permanent brake device for a motor vehicle drive train - Google Patents

Abstract

The invention relätes to a permanent brake device (18) for a motor vehicle drive train, comprising a retarder (IS) via which, in a braking mode., a braking torque c an be fed in on the drive side of a motor vehicle transmission {2} , The retarder (1.9) is incorporated h.ere on a arive~si.de part (17) of a starting element (3) of the motor vehicle transmission (2), which starting element serves within the motor vehicle drive train for connection to an output side (4) of a drive motor (1) , In order now, apart from a braking mode of the retarder (19) , to obtain a high degree of efficiency, fout at the same. tirrte to enable the braking torque to be fed in in a compact månner, the retarder (19) c an be connected for the braking mode, For this purpose, a driveshaft (22) of the retarder (19) is coupled to a first half (25) of a shift element (23), the second half (26) of which is connected to the drive-side part (17) of the starting element (3),. Figure 1

Description

lO ßw.)(I) *JJC) Permanent hrake device for a motor vehicle drive train The invention relates to a permanent brake device for a motor vehicle drive train, comprising a retarder via which, in a hraking mode, a braking torque can be fed in on the drive side of a motor vehicle transmission, wherein_ the retarder“ is incorporated. on aa drive~side part of a starting element of the motor vehicletransmission, which starting element serves within themotor vehicle drive train for connection to an output side of a drive motor. Furthermore, the invention relates to a motor vehicle drive train, in which an ahove~mentioned permanent brake device is used, and toa method for operating a permanent hrake device.Permanent hrake devices are used in motor vehicles, in particular in the sphere of commercial vehicles, andserve there as wear-free hrake systems for relieving arespective service hrake. A permanent brake device iscustomarily configured here as a hydrodynamic permanentbrake device and comprises a hydrodynamic retarder, in which flow energy of a liquid is used for generating a hraking torque. For this purpose, a customarilytoroidal working chamber, into which the liquid within the scope of a hraking mode is introduced, is defined in the retarder between a stator and a rotor, Therotating rotor entrains the liquid here via blades andconveys said liquid to blades of the stator where the liquid is retained and is subsequently conducted back again to the blades of the rotor. A delaying torque is exerted here on the rotor, wherein a magnitude of saidhraking torqne is controlled via the quantity of liquidWithin a permanent then introduced into the working chamher. device, a retarder is frequently the hrake incorporated on drive side of a motor vehicle transmission, as a result of which the step~up of the motor vehicle transmission can be used for stepping up La)CD LUUF _21-. the hraking torqne. A retarder ineorporateß in such a manner ie also referred to ae a primary retarder.

DE 41 22 628 Al reveale a permanent brake device for a motor vehicle drive train, in which_ a hydrodynamic retarder is connected on the drive side upetream of amotor vehicle transmission oonfigured ae a dual clntchtransmission. A driveshaft of the retarder is conpledhere via a step-up stage to a drive~side part of thedual clutoh of tie motor vehicle transmission, on whichpart a drive motor which is connected npetream of thtransmission is incorporated within the motor vehicle motor vehicle drive train. To this extent, a tïakingtorque generated in the braking mode of the retarder isfed in at the drive-side part of the dual clutoh.

Starting from the ahove~deecribed prior art, it ie nowthe the permanent hrake device for a motor vehicle drive train, ohject of preeen invention to provide a which permanent hrake device, apart from a hraking mode of a retarder, ie dietingniehed. by' a high degree of efficiency and in which, however, a hraking torqne can at the same time he fed in in a compact manner, Starting from the precharacterizing clanee of claim 1, this object ie achieved in conjunction with thecharacterizing features thereofe The dependent claimefollowing said claim each. reproduoe advantageone developments of the invention. Ei motor 'vehicle drive train :hi which ai permanent hrake device according to the invention ie need emergee from claim 9. Finally, a method for operating a permanent hrake device isdescribed in claim 10.

According to the invention, a permanent brake devicefor a nmtor vehicle drive train comprieee a retarder via which, in a hraking mode, a hraking torque can he 5.4šfl r 3 W drive side of a motor vehicle H1 ed in on the transmission. The retarder is ineorporated here via a drive-side part of a starting element of the motor vehicle transmission, which starting element eerves within the motor vehicle drive train for connection toen output side of a drive motor.retarder ie in the the particular a hydrodvnamio retarder which is oomposed inl According to invention, a manner basica ly known to a person skilled in the art of a stater and a rotor, wherein both the rotor and the etator are in each case equipped with hlades and between them. define a working' ohamber' preferahly“ offor example oil or the toroidal configuration. If a liquid, water, is then introduced into the working ohamher,liquid ie entrained via the hlades of the rotor and isthe the stater where said liquid is acoelerated in direction of the blades of stahilized and is conductedThe liquid which hack again to the hlades of the rotor. is conducted, hack acts in a delaying manner> on the stator, and therefore a hraking torqne is caused at therotor and also at the driveshaft connected thereto. Themagnitude of said hraking torque can be controlled herethe Alternatively thereto, via quantity of liquid which is introduoed. the retarder, however, can also be a ydrostatio retarder or an eleotrodynamio retarder.

Within. the soope of the invention, the retarder can furthermore firstly he connected by means of the directly tm: the drive~side part ofthe last» driveshaft thereof the with the starting element or else, however, interoonneotion of a step~up stage. In mentioned oase, during the driving of the drivesheft of the retarder, to the driveshaft thereof san aecordingly take place. A step~up stage oan be designed a step-up as a spur gear stage or else as a planetary' stage. if! lO ß-J(I) Furthermore, the retarder can lma plaoed_ ooaxially' oraxially offeet with respect to the drive~eide part of the etartind element.The invention now eomprieee the technical teaching thatthe retarder can he connected for the hreking mode hy edriveehaft. of thehalf of e connected to retarder~ being' coupled, to a first the second half of which is the shift element, the starting drive~side part of element, In other words, a driveeheft of the reterder can therefore he deooupled, apart from a hraking mode,from the drive~eide part of the starting element via ashift element which ie provided between the driveshaftA first to the driveshaft of the and the starting element. helf of said shift element ie then connected retarder while a second half is ooupled to the drive~ side part of the starting element.

Such ei configuration cd? a permanent brake device has the advantage here that the reterder can he connected in the region. of the etarting element of the motor vehicle transmission in a compact menner, hut et the same time, apart frmn a braking mode, because of the it ie possible to avoidthe decouplehility of the reterder, loeeee which originate from idling loeses of reterder, ae otherwise occur in particular in ahydrodynamio retarder' due to reoiroulation. of air orThis interoonneotion of the shift element between the drive» reeiduee of liquid. ie because, hy Keane of theside part of the starting element and the driveshaft ofthe targeted manner during the hraking mode. however, reterder, the retarder can. he switohed. on in e apart from e hreking mode, drive of the retarder is etopped 'i| because of eaid deeoupling of the drivesneft. in Contrast thereto, in the case of DE 41 22 628 Al, a driveeheft of a reterder ie permanently ooupled via the intermediete step~up stage to the drive-side part ofthe starting element oi the motor vehicle transmissionconnected downetream. In this respect, the retarder idling loeees occurring apart from e braking mode ere U! also permenehtly fed in, which leads to a corresponding deterioration in the efficiency.

According to the ihventioh, e “shift element” should hennderetood es meaning aa device Via which twolü components, which are otherwise rotatahle reletive toeach other, can he coupled to each other in terms ofthe rotetional movements thereof. A shift element herecan heeicelly be designed es e positive shift element,such es, for example, ae e claw clutch or looking15 syhchromeeh, or elee es e non-positive shift element,for\ example es a :milti-disc clutch. Furthermore, theshift element can be designed es e syhchronized shiftelement which, in the ruh~up to e connection of the twocomponents for conjoint rotation, cen match said20 components themselves in terms of the rotational speedthereoí, hut elternetively thereto, can also he ahuneynchrohized shift element in which matching of therotational epeeds hes to he carried out externally prior to the coupling.

Within the scope of the invention, the retarder can hepceitioned with the driveeheft thereof either coaxiallywith. reepect. to the drive-side part of the startingelement or else can lie axielly' offset with respect36 thereto. In addition, a etep~up stege can he providedhetween the driveeheft and the drive-side part of thestarting element, as a result of which, when theretarder ie ihcorporated, a ccrresponding step~up of e rotational movement to the driveshaft of the reterder 'udU! can he reelized. A step~up stege can he designed here ae e epur gear stage or elee as e plenetary stege. f.) b)Ul ~ e; According to one emhodiment of the invention, the shiftelement is designed as e powet shift element, By thismeans, the retarder can advantageonsly' he connectedeven under load, as a result of which a hraking modecan be speedily' initiatedn ln. a development. of thisemhodiment, the starting element of the motor vehicletransmission is then also oonfignred ae e power shiftelement, wherein. the starting element and the shiftelement are combined to form e olutch unit, in which adual olntoh is preferahly involved. By this means, ecompact arrangement of the starting element and of theshift element of the retarder is possible, The powershift elements which are combined to fotm e elutoh unitare particularly preferebly aetuable in each case via arespective disengaging element, wherein the disengagingelements ere arrangeo. eoncentricelly' with respect toeach other, The disengaging elements can then hecombined to forex a disengagement nnit, and thereforeactuatione of the starting element, and. of the shiftelement of the retardet are realited in e compact construction space.

Alternatively thereto, in e further refinementpossibility of the invention, the shift element iedesigned as a positive shift element, The configurationin the form of a positive shift element has theaävantage here that, in Contrast to non~positive shiftelements, in the open state virtnally no idling torquesoccur which, even in the open state of the respectiveshift element, result in the transmission of a certain torque. ïn a development of the above-mentioned refinement, theshift element is present as a positive, nnsynohronizeáshift element, wherein the driveshaft of the ietarderis eoupled. to a further shift element and een he brought via, the letter' into connection with e shaft UT which is oonneotahle to the drive~side part of thestarting element via a power shift element. Furthermore preferahly, the shaft here is a gear input shaft of the motor vehicle transmission, wherein, the power shift element is the starting element of the motor vehicle transmission. In addition, the motor vehicletransmission can be oonfigured here as a dual elutoh transmission, wherein the power shift element is then p rt of a olutoh unit, in particular of a dual clutoh.

In the case of such a design, matohing of the rotational speeds of the driveshaft of the retarder andof the drive~side part of the starting' element canundertaken before the unsynohronized shift the driveshaft of easily he element is closedt For this purpose,to the shaft, i.e. shaft, the retarder is initially ooupled optionallyi to the transmission input via theelement and suhsequently the shaft isthe the element for rotation therewith. Following this, 'I * r'-v'\ TŔSilli. L, further connected to drive-side part of starting becauseof the then rotational speedsbetween the drive-side part of the starting element and the prevailing parity of the driveshaft of the retarder, positive, unsynehronized shift element can then be closed.

A configuration of the motor vehicle transmission as a dual clutoh. transmission. also has the advantage that gear changing within the dual olutoh transmission can he undertaken under load and therefore even during a hraking mode of the retarder if the change here is made between gears assigned. to different transmission seotionst As a result, during the braking mode, a change can be made from a current gear to a differentgear* in. which. a step-up of a hraking torque of theretarder that is more suitable for the current driving state takes place.

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In a further emhodiment of the invention, the retarder is integrated. in the motor vehicle transmissionn By this means, the retarder can he arranged particularly compectly, particularly since, under some certain housing parts and feed lines tothe circumstenoes, the reterder can, be formed. et the same time by Alternativelv thereto, it is, transmission housing. however, also conceivable for the driveshaft of thereterder, and further components of the connection ofsame, to run 'ithin the motor vehicle transmission while the reterder itself is pleced externally onto the transmission housing. the the main claim or of the The invention_ is not restricted to stated combination of the features offnrthermorewith claims dependent thereon. Possibilities emerge of combining individual features one another even to the extent to which they emerge fromthe claims, the åescription helow of preferredembodiments of the invention or åirectly from thedrewinos. The reference in the olaims to the drawings hy the use of reference signs is not intenfieå to limit the soope of protection of the cleims.

Advantageous refinements of the invention which areexplained. below are illustrated. in the drewings, in which: Figure l shows a schematic view of part of aa motor vehicle drive train oomprising a permanent brake device according to a first emhodiment of the invention;Figure 2 shows e schemetic illustration of part of a motor vehicle drive train with ei permanent hreke device eooording to a second refinement option of the invention; UT lO *Fs; I* JLT! Figure 3 shows a echematic view of part of a motorvehicle drive train comprising a permanentbrake device according to a third emhodimentof the invention; and Figure 4 shows a schematic illustration of part of amotori vehicle drive train. with ei permanenthrake device according to a fourth refinementoation of the inventionø Figure 1 shows a schematic view of part of a drive train. of a motor vehicle, which. is in. particular a commercial vehicle, such as, for example, a lorry. A drive motor l hich is only partially illustrated in the present case an is configured as an internalcombuetion engine is provided here in this motor vehicle drive traini Within the motor vehicle drive train, a motor vehicle transmission 2 is then connected downstreani of the drive motor* l, said. motor vehicleable to he to an output side 4 of a orankshaft transmission 2 being connected via a starting element 35 of the drive motor 1.the motor vehicle transmission 2 In the present case, is realised in a group design and is composed of a main group 6 and a downstream range group 7. While the range group 7 is configured in a planetary design, the maingroup 6 is present as a transmission. of theoountershaft type, in which a transmission input shaft8 and a transmission output shaft 9, which at the sametime forms the input of the range group 7, runcoaxially with respect to each other, The transmission input shaft 8 and the transmission output snaft 9 can then firstly be connected directly to each other for rotation therewith, in order to define a direct through-drive, and, secondly; can se coupled to each t.) LOL? LV! other via a plurality of spur gear stages 10 to 14. In the last-mentioned case, a force flow is guided here ineach case via a counterehaft 15 running axiallyparallel to the transmission input shaft 8 and to thetransmission output shaft 9.

As can. furthermore he seen from figure 1, thetransmission. input shaft 8 is also connected, to anoutput-side part 16 of the starting element 3, the drive-side part 17 of which is ooupled to the output side 4 of the drive motor l for rotation therewith. In the present case, the starting element 3 is configured as a power shift element in the form of a wet~runningeeparating olutohl which, when the output side 4 isaotuated, oonneots to the transmission. input shaft 8 for rotation therewith, A permanent hrake device 18 which is oonfignredaccording to a first embodiment of the invention andhas a retarder 19 in the form of a hydrodynamicretarder is also provided within the motor vehicledrive train. The retarder 19 ie oonsequently oomposedin a manner hasically known to a person skilled in theart of a stater 20 and a rotor 21 which (notillustreted speeifioally' here) are provided_ withrespective blades and define a toroidally* configured working ohamher between them. A quantity of liquid can then be introduced into said working Chamber, wherein the liquid can he oil or else water. The quantity of liquid introduoed in each case into the working Chamber is then entrained via the hlades of the rotating rotor 21 and accelerated in the direction of the hlades ofthe stater 26 where said quantity of liquid isstahilized and is conducted hack again to the blades ofthe rotor 21. In the process, ai delaying torque is exerted on the rotor 21, wherein the magnitude of said hraking torque can he defined by the qnantity of liquid NäC3- ell.. introdnced. The retarder 19 is also integrated here in housinq (not illustreted specifically a. transmissionhere) of the motor vehicle transmission 2.rotor* 21 is driveshaft 22 of the The arranged on aa for rotation therewith, said driveshaft 22, shaft, retarder lå as a hollow running eoarially on the transmission input shaft 8. Said driveshaft 22 can then he connected to the output side 4 of the drive motor 1, likewise for rotation. therewith, vie. a shift element23, wherein the shift element 23 is designed here es a power shift element and is combined with the startingL3 to form a cflntch unit 24 ina first half 25 23 is provided on the driveshaft the form of athe element dual olutch. For this purpose, shift element foristhe rotation therewith, whereas a second half Û ro \a Qm anwa W connected together with the drive~side part 17 starting element 3 to the output side 4. ln this respect, the eoarially arranged reterder 19 can he connected, even under load, with the aid of the power shift element 23, as a result of which a hraking mode of the retarder 19 can he initiated with little timedelay. The starting element 3 and also the shiftelement 23 can each he ectueted here Via an associated disengaging' element, wherein. the disengaging elements here are combined in a manner lying concentrioally with respect to each other to form a dieengagement unit 27.

If a hraking torque is then to he introduced into the motor vehicle drive traint via the retarder 19, the working Chamber of the retarder 19 ie filled with the corresponding amount of liquid and, at the same timethe shift element 23transmit the of the therewith or else offset in time, 'i ie aotuateo. In order then also to oorresponding' hreking torque to drive wheels 'i motor vehicle, a respective gear should also he shifted both in the main group 6 and in the range group 7 and 2C l2 element 3 should he closed. By suitable selection of an overall etep~up of the motor vehicle transmission. 2, the hraking torque generated hy the retarder^ l9 can. he steppedt up in a correspondingly suitable manner for a current driving speed.

Figure 2 shows a schematic view of part of a motorvehicle drive train which suhstantially eorresponds here to the variant from figure 1. The sole difference here is that a retarder 28 is not arranged ooaxially,but rather in an arially offset manner hy a driveshaft29 of the retarder 28 being coupled via a step-up stageshaft 31connected via the shift element 23 to the output side 41 for 30 to a hollow which, in turn, can he of the drive motor rotation therewith. In this respect, a rotational movement ot the hollow shaft 31can be stepped up via the step-up stage 30 to the driveshaít 29 such_ that a higher* driving' rotational speed cnf the retarder 28 can lxa produced. Otherwise,the configuration of a permanent hrake device 32 havingthe retarder 28 and also the further configuration ofthe motor vehicle drive train oorrespond to the variantand therefore reference is made according to íigure 1, to what has been described in this regard.

Furthermore, figure 3 shows a schematio partial view ofa motor vehicle drive train which eomprises a permanenthrake embodiment, A thirdthe device 33 configured according to a difference here with regard to previous variants according to figure 1 and íigure 2 isa motor vehicle transmission. 34 whioh isthe downstream of the drive motor 1 also that connected. within motor vehicle drive train is configured as a dualsaid, motor vehicle olutoh transmission. Accordingly, transmission (only partially illustrated in the presentcase) has two transmission input shafts 35 and 36 which run coarially with respect to each other and of which -. 13» the transmission input sheft 36 as a hollow shaft runs in a manner lying radially around. the transmission input shaft 35 extending aïially therethrongh. The two transmission input shafts 35 and 36 can each heconnected via an associated power shift element 37 or 38 to the output side 4 for rotation therewithi The power* shift elements ”7 and. 38 are combined. here to 3forex a olutoh. unit 39 in. the forwi of a dual olutoh which forms a starting element 40 of the motor vehicle transmission 34. 33 again has a retarder 41 tlie The permanent brake device which. is oonfigured in aocordance with variants figure 1 and. figure 2 as ei hydrodynamiothen accordingi to retarder. A driveshaft 42 of the retarder 41 isoonneoted via a step-up stage 43 lying in between to aruns ooaxially with respect to hollow shaft 44 which the transmission input shafts 35 and 36.

A hraking torque of the retarder 41 can then he fed inon the drive side of the motor vehicle transmission 34shift drive motor l shaft 44 being side 4 of the hy the hollow oonpled via a element 45 to the output for rotation therewith. The shift element 45 isdesigned here as a positive, unsynohronieed shiftelement in the form of a elaw clntch, the first half 46of which is provided on the hollow shaft 44 forrotation. therewith, whereas a second. half 47 of the shift element 45 is connected to a drive~side part 48 of the starting element 40.

Since the shift element 45 is an unsynchronized shift element, before same is aetnatedi a trotationel speed to prevail, at least approximately' between 46 and. 47. parity' has the halves In order then to produce samethe hollow 42 of the hefore the retarder 41 is inoorporated, shaft 44 and therefore also the driveshaft U: lü D.)(I) 14retarder 41 are ooupled to a further shift element 49,which ie designed as a looking synohromesh and, whenaotuated, oonneots the hollow shaft 44 to “the transmission input shaft 36 for rotation therewith. ln the present case, the shift element 49 is combined here of a spur gear stage 50 of the 34 to with a shift element motor vehicle transmission form ai shift device 51. ln specific terms, the retarder 41 is then incorporated hy the hollow shaft 44 first of all being connected to the transmission input shaft 36 via the shift element 49 an then the shift element 38 heing actnated.

This then has the conseqnence that the drive-side part power 48 of the starting element 4G and the hollow shaft 44 run at the same rotational speed, as a result of whichshift If this then takes place, the nnsynohronized element 45 can easily he aotuated. the shift element49 is opened. again. and_ the respeotively' appropriategear in the motor vehicle transmission 34 is shifted.In addition, during the course of the hrahing mode, agear change can be undertaken under load via the powereven during a shift elements 37 and 38, and therefore, hraking mode of the retarder el, a transfer can be made into a gear which. is more suitable for* the current driving state of the motor vehicle.

Finally, figure 4 also shows a sohematio illustrationof part of a motor vehicle drive train which oompriseshrake refinement option of devioe 52the a permanent aooording to a fourth invention. The motor vehicle drive train and also the permanent hrake device 52 snbstantially oorrespond here to the oonfigurations of th. variant aooording to figure 3, wherein, as the sole difference, ai retarderl 53 is arranged. ooaxially with respect to the transmission input shafts 35 and 36 of the motor vehicle transmission 34. In this respect, a the retarder 53 driveshaft 54 of ihollow eheft en the tranemieeien input ehafte 35 end 36:nede of the retarder' 53, ie side. 4 of the drive: motor* 1 durine' the braking end, cenneeted to the output without e step up stage lying in~betweenr Said drivesheft 54 is therefore else ceupled directly to ene half 55 of an uneynehronized shift element 56 and to a further shift element 57. The further connection of the shift elements 55 and 57 and else the manner ef incorporeticmz ef the retarder 53 irl the Ébreking :modethen correepen te the variant accerding te figure 3, and therefore reference is made to that whicn hes been described in this regard, A reterder can be ineorpereted in e compact manner bymeans of the refinemente according to the inventiøn ofe permanent brake devie«, wherein, apart from a breking mode of the reterder, low power lesees occur end therefore e high degree of efficiency can be realized.

Claims (2)

1. 7 5. Permanent brake device (33; 2) according to Claim 4, characterized in that the shift element (45; 56) is present as a positive, unsynchronized shift element, wherein the driveshaft (42; 54) of the retarder (41; 53) is coupled to a further shift element (49; 57) and can be brought via the latter into connection with a shaft which is connectable to the drive-side part (48) of the starting element (:40) via a power shift element. 6. Permanent brake device (33; 52) according to Claim 5,characterized in that the shaft is a transmission input shaft (36) of the motor vehicle transmission (34), wherein the power shift element is the starting element (40) of the motor vehicle transmission (34). 7. Permanent brake device (33; 52) according to Claim 6, characterized in that the motor vehicle transmission (34) is configured as a dual clutch transmission, wherein the power shift element is part of a clutch unit (39), in particular of a dual clutch_ 8Permanent brake device (18; 32; 33; 52) according to Claim 1, characterized in that the retarder (19; 28; 41; 53) is integrated in the motor vehicle transmission (2; 34). 9. Motor vehicle drive train comprising a permanent brake device (18; 32; 33; 52) according to one or more of Claims 1 to 8. 10. Method for operating a permanent brake device (33; 52) according to one of Claims 5 to 7, wherein the 35 driveshaft (42; 54) of the retarder (41; 53) is first of all coupled to the shaft via the further shift element (49; 57) and then the shaft is connected to the 18 drive-side. part (48) of the starting. element (40) for rotation therewith, and wherEin the positive, unsynchronized shift element (45 56) is then closed. 17 24 23 26 18 21 19 \ \ 1314 4 16 I 27 22 6 11 12 ce) 38 39 33 48 45 42 41 43 51 ,I• / / \1 I , ,Hi/ / i/ 1/ 1'/ / ./ ,/_ /;,/,\ ,1 ;\ '‘ 1 / i ,,\ /I.iI/I 4 35 47 46 34 44 36 49 , ' e e !,„e . 4 1 4 - 54 34 36