DE10161852A1 - Motorized vehicle's drive path incorporates drive shaft, engine, coupling, gear input shaft for transmission gear driven by differential and synchronizers and damper - Google Patents

Abstract

The drive path incorporates the drive shaft (53) of a drive engine (51) connected by a coupling (54) to a gear input shaft (55) belonging to a transmission gear (56) which is driven by a differential (57) which in turn drives wheel drive shafts. The transmission gear has at least one synchronizer (70a,b,c) which has at least one damping device operating in a peripheral direction. The drive shaft is connected to a coupling-half on the drive engine side.

Description

The invention relates according to claim 1 a Motor vehicle drive train and according to claim 5 a Method for noise reduction in such.

• - Front-quer-Antrieb mit Vorgelegegetriebe,
• - Front-längs-Antrieb mit Vorgelegegetriebe,
• - Heckmotor-Antrieb mit Vorgelegegetriebe und
• - Mittelmotor-Antrieb mit Vorgelegegetriebe

bezeichnet. Motor vehicle drive trains are already known, in which a drive shaft of a drive motor, a transmission input shaft of a countershaft transmission which can be coupled thereto via a clutch, a differential driven by the latter and wheel drive shafts driven by the latter are arranged in a common region, wherein the transmission comprises a plurality of synchronizers. These automotive powertrains are commonly referred to as

• - front-transverse drive with countershaft transmission,
• - Front-longitudinal drive with countershaft transmission,
• - Rear engine drive with countershaft transmission and
• - Mid-engine drive with countershaft transmission

designated.

In a disadvantageous way, motor vehicles appear in particular with front-transverse drive and manual transmission relatively loud, since the entire drive train in the engine compartment of the motor vehicle is arranged, with the sound through the wheel arches to the outside is directed.

From the Mercedes A-Class with manual transmission is to Noise reduction of the drive train in front-transverse construction the Use of a so-called dual-mass flywheel between Drive motor and countershaft transmission known.

The not previously published DE 101 29 097.7 deals with a Synchronizer with reduced noise level. To the synchronizer has two synchronizer rings, which under a biasing force frictionally connected to a Concurrent body abut.

Furthermore, from EP 0 976 941 B1 a Synchronizer for a vehicle transmission known. This synchronizer has a synchronizer body or synchronizing body and two synchronizing rings, over each two rotating parts with differential speed to one another same speed can be brought. A Presynchronization takes place via a ball-and-spring-sliding block System.

To be in a starting position of the synchronizer ring before a Synchronizing a contact between the synchronizer ring and one with the synchronizer ring during one Synchronisiervorgangs corresponding claw wheel and thereby conditional drag moments and bouncing noise is avoided proposed that at least one sliding block of the ball-spring Gleitstein system is designed permanent magnetic. Of the ferromagnetic synchronizer ring is powered by a magnetic Attraction of the sliding block fixed in the axial direction or held in an axial position in which a play-related contact between the synchronizer ring and the Claw wheel is avoided.

The object of the invention is to provide a quiet and cost-effective and to create a motor vehicle.

This object is achieved by the features of Motor vehicle drive train of claim 1 and the Process according to claim 5 solved.

For this purpose, a motor vehicle drive train is proposed, which is arranged in the region of an axis. Of the Powertrain has a countershaft with a clutch. The Countershaft is provided with several synchronizing devices, the at least one circumferentially effective Have damping device. The clutch is as One-mass flywheel executed.

An advantage of the motor vehicle drive train, which in the Area of an axis is arranged that this no long and thus torsionally flexible propeller shaft or drive shaft having. Thus, not even in a long Cardan shaft or drive shaft typical torsional vibrations with their high noise emission. The short and torsionally rigid components of the drive train according to the invention are characterized advantageously by small Vibration amplitudes with correspondingly lower Noise emission.

The use of a synchronizer with in Circumferential direction of effective damping device reduces the Noise emission in an advantageous manner in addition to a Speed band of the drive train. It can do this Damping device at vibration amplitude peaks of the Adherent state go into the sliding friction state, so that the Energy of vibration amplitude peaks due to friction in the damping device is consumed. The more Synchronizers with damping device are provided, the more energy can be absorbed. In particularly advantageous way to further Noise emission reduction of each synchronizer be assigned to two damping devices.

An advantage of using a countershaft transmission is that, that synchronizers with damping devices particularly cost-effective to integrate. Further, a Countershaft transmission, for example, compared to one Planetary gear lower inertia on, from what lower vibration amplitudes with correspondingly lower Noise emission result. In addition, one has Countershaft transmission advantageously a very cheap Efficiency.

The essentially non-rotatable coupling of the drive shaft with the drive motor side coupling half can in particular Advantageously by means of a Einmassenschwungrades be realized. Opposite a dual mass flywheel the non-rotatable coupling of the drive shaft with the drive motor-side coupling half essential cost-effective. Furthermore, a motor vehicle drive train with non-rotatable coupling of the drive shaft with the drive motor-side coupling half more agile than a Powertrain with dual-mass flywheel, as such always with a delayed response to the Power demand of the driver reacts. For this The reason is the use of the invention in a motor vehicle with rear engine drive or with mid-engine drive, which Usually designed more athletic, especially advantageous.

Another advantage of the rotationally fixed coupling of the drive shaft with the drive motor side coupling half is that not typical for a dual mass flywheel Resonant vibrations in the range below the idle speed of the drive motor occur. Thus, by the Invention a low-noise, component-gentle starting and Shutting down the drive motor when driving through the Idle range possible.

Claim 2 shows a particularly advantageous Embodiment of the invention, in which the Damping device particularly inexpensive in the Synchronizer can be integrated.

Claim 4 shows a particularly advantageous Embodiment of the invention, in which a noise emission the motor vehicle drive train at speeds of Transmission input shaft below idle speed of Drive motor due to abutting tooth flanks the gears of the countershaft transmission is reduced.

Claim 5 shows a method in which in particular Advantageously, the noise emission when stopping and Starting the drive motor can be reduced.

Further advantages of the invention will become apparent from the following Subclaim, the description and the drawings.

The invention is described in detail below with reference to FIG illustrated embodiment and four others briefly Outlined embodiments described in more detail.

Show it

• - eine Getriebeeingangswelle eines Schaltgetriebes,
• - ein Differential und Radantriebswellen

umfasst, Fig. 1 shows a motor vehicle power train having a drive shaft of a drive motor, a clutch,

• a transmission input shaft of a manual transmission,
• - a differential and wheel drive shafts

includes,

Fig. 2 is a longitudinal section through a part of a synchronization device according to the invention,

FIG. 3 shows the synchronizing device from FIG. 2 after an actuating travel of a synchronizing ring, FIG.

Fig. 4 shows an enlarged detail IV from Fig. 3,

Fig. 5 shows an enlarged section V of Fig. 3,

Fig. 6 is a front view of a synchronizer ring of Fig. 2,

Fig. 7 is a front view of a constant velocity body of Fig. 2,

Fig. 8 is a motor vehicle in which a motor vehicle power train shown in FIG. 1 applies, in this automotive the drive motor is located transversely behind the front axle,

Fig. 9 a motor vehicle, wherein the drive motor is located longitudinally in front of the front axle,

Fig. 10 is a motor vehicle, wherein the drive motor is located across the front axle,

Fig. 11 shows a motor vehicle with the drive motor in the region of the rear axle, which is designed as a rear-engine drive and

Fig. 12 shows a motor vehicle with the drive motor in the region of the rear axle, which is designed as a mid-motor drive.

Fig. 1 shows a motor vehicle drive train, in which a drive motor 51 located transversely behind a front axle 52nd The motor vehicle drive train comprises a drive shaft 53 of the drive motor 51 , a clutch 54 , a transmission input shaft 55 of a countershaft transmission 56 , a differential 57 and not shown in detail wheel drive shafts in the region of the front axle 52nd

The drive shaft 53 of the drive motor 51 is rotatably connected to a flywheel 58 of the clutch 54 . The flywheel 58 is bolted to a clutch cover 59 . Thus, the flywheel 58 and the clutch cover 59 form a clutch housing within which a plate spring 60 , a pressure plate 61 and a clutch disc 62 are arranged. The clutch disc 62 has friction linings, which are braced between the pressure plate 61 and the flywheel 58 . This tension is achieved with the plate spring 60 , which is radially outwardly supported on the one hand on the clutch cover 59 and on the other hand on the axially displaceable pressure plate 61 .

The clutch disc 62 is rotatably connected radially inwardly by means of a spline toothing with the transmission input shaft 55 . In a radially central region, the clutch disc 62 has a plurality of circumferentially distributed bow springs 63 , so that the flywheel 58 in the engaged state of the clutch 54 via the elastic energy storage - that is the bow springs 63 - limited rotatably supported relative to the transmission input shaft 55 . Radially inside the bow springs 63 an axially strained friction disc unit 71 is arranged. This friction disc unit 71 functions as a damper, which is connected in series with the bow springs 63 . The engagement and disengagement of the clutch 54 takes place by means of a stylized central release 64 , which is supported on the one hand on a transmission housing 65 of the countershaft transmission 56 and on the other hand supported with an axially displaceable piston via a release bearing 66 on the radially inner edge of the plate spring 60 .

The countershaft transmission 56 comprises a countershaft 67 parallel to the transmission input shaft 55 . Both the transmission input shaft 55 and the countershaft 67 carry fixed and idler gears. In each case a fixed gear of a shaft 55 or 67 meshes with a loose wheel of the other shaft 67 and 55, respectively. By means of one of three synchronizers 70 a, 70 b, 70 c is one of the idler gears with this associated shaft 55 and 67 rotatably coupled. The countershaft transmission 56 then has this gear pairing - ie a fixed gear with a idler gear associated with this - corresponding translation. The other idler gears remain rotatable relative to the shaft 55 and 67 and in meshing engagement with the fixed wheels of the other shaft 67 and 55, respectively. Between two idler wheels each one of the synchronizers 70 a, 70 b, 70 c arranged to make with this one synchronizers 70 a and 70 b and 70 c two idler gears separately coupled.

A one-piece with the countershaft 67 ausgestaltetes further fixed gear meshes with a spur gear of the differential 57 which transmits a drive torque to the two wheel drive shafts, not shown. These Radantriebswellen are in spline hubs 68 a, 68 b of bevel gears 69 a, 69 b of the differential 57 plugged.

• - vom Antriebsmotor 51
• - über die Kupplung 54,
• - über die Getriebeeingangswelle 55
• - über eine Zahnradpaarung,
• - über die Vorgelegewelle 67,
• - über das Differential 57,
• - über die Radantriebswellen

auf nicht näher dargestellte Antriebsräder übertragen. An idealized drive torque is thus in the motor vehicle drive train shown

• from the drive motor 51
• via the coupling 54 ,
• - About the transmission input shaft 55th
• - via a gear pairing,
• via the countershaft 67 ,
• - via the differential 57 ,
• - over the wheel drive shafts

transferred to non-illustrated drive wheels.

Even if the idealized drive torque is transmitted exclusively via a gear pair, so occur due to inertia of the components of the synchronizer 70 a, 70 b, 70 c at each of the synchronizers 70 a, 70 b, 70 c forces. These forces are, however, offset by a in Fig. 2 to Fig. 7 explained in more detail damping device.

FIG. 2 shows a part of one of the three identical synchronizing devices 70 a, 70 b, 70 c from FIG. 1.

• - einen Gleichlaufkörper 16 und
• - einen in axialer Richtung 24 vor dem Gleichlaufkörper 16 angeordneten Synchronring 14 und
• - einen in axialer Richtung 24 nach dem Gleichlaufkörper 16 angeordneten Synchronring 15.

This part of the synchronizer comprises

• - A synchronizing body 16 and
• - An arranged in the axial direction 24 in front of the synchronizing body 16 synchronizer ring 14 and
• - An arranged in the axial direction 24 after the synchronizing body 16 synchronizer ring 15th

The synchronizer rings 14 , 15 are held in their initial positions before a synchronization process on the damping device 10 with a holding force. As long as forces due to inertia of the synchronizing body 16 and the synchronizer ring 15 do not exceed a certain level, the damping device 10 avoids in the initial positions of the synchronizer rings 14 , 15 via a respective connection 11 , 11 ', via one frictional connection 11 , 11th ', Relative movements, in particular in the circumferential direction 21 , 22 , between the synchronizing body 16 and the synchronizer rings 14 , 15th

The damping device 10 has three evenly distributed over the circumference of the synchronizer ring 14 , 15 , designed as Schraubenzugfedern spring elements 17 ( Fig. 2 and 6). The spring element 17 is guided by a in the circumferential direction 21 , 22 extending slot 19 of the synchronizing body 16 and through a through hole 25 of the synchronizer ring 14 and through a through hole 26 of the synchronizer ring 15 and is in each case hooked to its hook-shaped ends in transverse pins 27 , 28 mounted ( Fig . 2, 6 and 7). The cross pin 27 is recessed on a side facing away from the synchronizing body 16 of the synchronizing ring 14 in a recess 29 thereof, and the transverse pin 28 is recessed on a side facing away from the synchronizing body 16 of the synchronizer ring 15 in a recess 30 thereof sunk. Threads 31 of the spring element 17 are arranged in the slot 19 , and rectilinear portions 32 , 33 of the spring element 17 are respectively in the through holes 25 , 26 of the synchronizer rings 14 , 15 are arranged.

The spring elements 17 act on both synchronizer rings 14 , 15 and pull them with a spring force axially in the direction of synchronizing body 16 , so that the synchronizer rings 14 , 15 with their the synchronizing body 16 facing sides, each with a radially outer, annular contact surface on radially outer, annular Contact surfaces 20 , 20 'of the synchronizing body 16 come to rest. The contact surfaces 20 , 20 'of the synchronizing body 16 are roughened, so that in comparison to a smooth surface of the synchronizing body 16, a larger coefficient of adhesion occurs. It would also be possible to coat the synchronizing body 16 , for example in a sintering process.

Between the contact surfaces of the synchronizer rings 14 , 15 and the contact surfaces 20 , 20 'of the synchronizing body 16 , the frictional connections 11 , 11 ', and indeed the spring elements 17 are designed in such a way that caused by the spring elements 17 normal force multiplied by a present Haftreibwert is greater than on the synchronizer rings 14 , 15 acting, caused by torsional vibration acceleration forces. Furthermore, the synchronizer rings 14 , 15 are centered on the synchronizing body 16 via the damping device 10 or via the normal force.

However, the normal force is smaller than a force acting on the synchronizer ring 14 , 15 Vorsynchronisationskraft in the axial direction or is uniformly distributed over the circumference pressure pads 35 presynchronization force greater than the normal force. 34 is initiated and the pressure pieces 35, a pre-synchronization via a non-illustrated shift fork, a sliding sleeve, and, for example, the synchronizer ring 15 loaded with a Vorsynchronisationskraft in axial direction 24 via the plungers 35, the synchronizer ring 15 is lifted from the synchronizing body 16 in axial direction 24 ( Fig. 3). The connection 11 between the synchronizer ring 15 and the synchronizing body 16 is separated, and the synchronizer ring 15 can turn in the circumferential direction 21 or 22 in its blocking position, the slots 19 each allow a free movement of the spring elements 17 to the synchronizing body 16 .

Instead of pure frictional connections 11 , 11 'are also form-fitting connections 12 , 13 between the synchronizing body 16 and the synchronizing rings 14 , 15 conceivable, as indicated in Fig. 2 and 3. The positive connection 13 is achieved with formed on the synchronizing body 16 as projections 36 formed positive locking elements, which engages in the initial position of the synchronizer ring 15 in a locking teeth 23 of the synchronizer ring 15 . The ratchet teeth 23 thus form interlocking elements for the positive connection 13th

The positive connection 12 is achieved with recesses in the synchronizing body 16 attached, designed as pins 37 positive locking elements, which engage in the initial position of the synchronizer ring 14 in recesses formed as form-locking elements of the synchronizer ring 14 positively.

The interlocking elements of the form-locking connections 12 , 13 have in the initial positions of the synchronizer rings 14 , 15 each have a cover 40 which is smaller than an actuation path 41 of the synchronizer rings 14 , 15 in or against the axial direction 24 to a corresponding coupling body, not shown so that the positive connection 12 or 13 is separated by the movement of the synchronizer ring 14 and 15 in the direction of the respective coupling body before the synchronizer ring 14 or 15 comes into contact with the corresponding coupling body ( Figures 3 and 5). Fig. 3 shows the synchronizer ring 15 just before contact with a corresponding coupling body, wherein the positive connection 13 is disconnected.

Instead of spring elements 17 designed as a helical tension spring, bow-shaped spring elements 18 can also be used, as is indicated schematically in FIGS. 2 and 4. The bow-shaped spring element 18 is arranged radially within the sliding sleeve 34 and radially outside of the synchronizing body 16 and the synchronizing rings 14 , 15 in a free space and engages over the synchronizing body 16 and the synchronizer rings 14 , 15 in the axial direction 24 . The bow-shaped spring element 18 acts with its radially inwardly pointing ends facing away from the synchronizing body 16 sides of the synchronizer rings 14 , 15 axially in the direction of the synchronizing body 16 and presses the synchronizer rings 14 , 15 with their contact surfaces against the contact surfaces 20 , 20 'of the synchronizing body 16 . The S-shaped or mirrored to curved ends of the spring element 18 are recessed in recesses 38 , 39 of the synchronizer rings 14 , 15 .

In a turnover operation of the synchronizer ring 14 and 15 , a relative movement between the synchronizer rings 14 , 15 and between the turning synchronizer ring 14 and 15 and the synchronizing body 16 is compensated by the spring element 18 by this tilted about its longitudinal axis, without being much further tensioned to become. By the S-shaped or mirrored to curved ends of the bow-shaped spring element 18 a punctual support between the spring element 18 and the synchronizer rings 14 , 15 and a small friction associated with the tilting of the spring element 18 is achieved.

FIG. 8 shows a motor vehicle in which a motor vehicle drive train according to FIG. 1 is used. In this motor vehicle, the drive motor 51 is located transversely behind the front axle 52 .

• - eine Antriebswelle des Antriebsmotors 151,
• - eine mit dieser über eine nicht näher dargestellte Kupplung koppelbare Getriebeeingangswelle eines Vorgelegetriebes 156,
• - ein von diesem angetriebenes Differential und
• - von diesem angetriebene Radantriebswellen

in einem gemeinsamen Bereich der Vorderachse 152 angeordnet. Das Vorgelegetriebe 156 weist Synchronisiereinrichtungen auf, welche in Umfangsrichtung wirksame Dämpfungseinrichtung aufweisen. Die Antriebswelle ist im wesentlichen drehfest mit einer antriebsmotorseitigen Kupplungshälfte der Kupplung verbunden, so dass die Kupplung ein Einmassenschwungrad darstellt. FIG. 9 shows a motor vehicle in which the drive motor 151 is located longitudinally in front of the front axle 152 . In the motor vehicle drive train of this motor vehicle

• a drive shaft of the drive motor 151 ,
• a transmission input shaft of a countershaft transmission 156 , which can be coupled thereto via a clutch (not shown),
• - A driven by this differential and
• - driven by this drive shafts

arranged in a common region of the front axle 152 . The counter gear 156 has synchronizers having circumferentially effective damper means. The drive shaft is substantially non-rotatably connected to a drive motor-side coupling half of the clutch, so that the clutch is a Einmassenschwungrad.

Since the drive motor 151 is arranged longitudinally, the motor vehicle drive train, in contrast to the exemplary embodiment according to FIG. 1, has an additional 90 ° bevel gear toothing.

• - eine Antriebswelle eines Antriebsmotors,
• - eine mit dieser über eine nicht näher dargestellte Kupplung koppelbare Getriebeeingangswelle eines Vorgelegetriebes 256,
• - ein von diesem angetriebenes Differential und
• - von diesem angetriebene Radantriebswellen

in einem gemeinsamen Bereich der Vorderachse 252 angeordnet. Das Vorgelegetriebe 256 weist Synchronisiereinrichtungen auf, welche in Umfangsrichtung wirksame Dämpfungseinrichtung aufweisen. Die Antriebswelle ist im wesentlichen drehfest mit einer antriebsmotorseitigen Kupplungshälfte der Kupplung verbunden, so dass die Kupplung ein Einmassenschwungrad darstellt. FIG. 10 shows a motor vehicle in which the drive motor 251 is located across the front axle 252 . In the motor vehicle drive train of this motor vehicle

• a drive shaft of a drive motor,
• a transmission input shaft of a countershaft transmission 256 which can be coupled thereto via a clutch, not shown in detail,
• - A driven by this differential and
• - driven by this drive shafts

arranged in a common region of the front axle 252 . The counter gear 256 has synchronizers having circumferentially effective damper means. The drive shaft is substantially non-rotatably connected to a drive motor-side coupling half of the clutch, so that the clutch is a Einmassenschwungrad.

The motor vehicle drive train of this motor vehicle is similar to the motor vehicle drive train shown in FIG .

Fig. 11 shows a motor vehicle with the drive motor 351 in the region of the rear axle 352 , which is designed as a rear-engine drive.

Fig. 12 shows a motor vehicle with the drive motor 451 in the region of the rear axle 452 , which is designed as a mid-motor drive.

• - eine Antriebswelle des Antriebsmotors 351 bzw. 451,
• - eine mit dieser über eine nicht näher dargestellte Kupplung koppelbare Getriebeeingangswelle eines Vorgelegetriebes 356 bzw. 456,
• - ein von diesem angetriebenes Differential und
• - von diesem angetriebene Radantriebswellen

in einem gemeinsamen Bereich der Hinterachse 352 bzw. 452 angeordnet. In the motor vehicle drive trains of the motor vehicles of FIG. 11 and FIG. 12 are

• a drive shaft of the drive motor 351 or 451 ,
• a transmission input shaft of a countershaft transmission 356 or 456 which can be coupled thereto via a clutch, not shown in detail,
• - A driven by this differential and
• - driven by this drive shafts

arranged in a common region of the rear axle 352 and 452 , respectively.

The countershaft gear 356 and 456 has synchronizers, which have circumferentially effective damping device. The drive shaft is substantially non-rotatably connected to a drive motor-side coupling half of the clutch, so that the clutch is a Einmassenschwungrad.

Since the drive motor 351 or 451 is arranged longitudinally, the motor vehicle drive train similar to the exemplary embodiment according to FIG. 9 has an additional 90 ° bevel gear toothing.

Fig. 13 shows in the diagrams a.), B.), C.), D.) Structure-borne noise emissions of various drive trains over time t. According to diagram e.) Falls over the time t, the speed of the drive motor of idle speed n _L to half idle speed n _L / 2. It is always a motor vehicle powertrain with the drive motor across the front axle and a countershaft transmission.

The speed drop is shown in FIG. 13e.) As linear falling with superimposed small waves.

In the motor vehicle drive train according to FIG. 13a.) An additional elasticity is introduced for noise reduction. The structure-borne noise increases massively with decreasing speed.

In the motor vehicle drive train according to FIG. 13b.) In contrast to the diagram previously no additional elasticity is introduced. The clutches for switching the gear pairings have no synchronizer rings, but are designed as pure jaw clutches. It occurs essentially only a structure-borne noise, which is due to the striking of the tooth flanks of the gears of the countershaft transmission. Due to the omission of synchronizers also no synchronizer ring rattle can occur.

• - Dämpfungseinrichtung an den Synchronisiereinrichtungen,
• - Einmassenschwundgrad und
• - elastischem Kraftspeicher zwischen schaltgetriebeseitiger Kupplungshälfte und Getriebeeingangswelle.

FIG. 13c.) Shows the behavior of a motor vehicle drive train according to FIG. 1, ie with

• Damping device on the synchronizers,
• - one-fold degree of fading and
• - Elastic energy storage between switching gear side coupling half and transmission input shaft.

It can be seen clearly that compared to the - from the structure-borne noise emission view "optimal" - waiver of synchronizer rings according to FIG. 13b.) No increase in structure-borne noise is recorded.

• - der Antriebsmotordrehzahl,
• - der Normalkraft Fn der Federelemente der Synchronisiereinrichtung und des
• - Haftreibungskoeffizienten µ₀

gilt folgendes:
Die Normalkraft F_n der Federelemente an der Reibflächenpaarung und der Haftreibungskoeffizient µ₀, der an der Reibflächenpaarung wirkt, sind derart abgestimmt, dass Umfangskräfte infolge der Massenträgheiten zwischen dem Gleichlaufkörper und dem Synchronring überschritten werden, wenn sich die Getriebeeingangswelle mit einer Drehzahl unterhalb der Leerlaufdrehzahl n_L des Antriebsmotors dreht. Somit wird sichergestellt, dass die Dämpfung und damit auch die Reibung zwischen dem Gleichlaufkörper und dem Synchronring hauptsächlich beim Durchschreiten der Leerlaufdrehzahl erfolgt. Regarding the vote

• the drive motor speed,
• - The normal force Fn of the spring elements of the synchronizer and the
• - static friction coefficients μ ₀

the following applies:
The normal force F _{n of} the spring elements on the Reibflächenpaarung and the static coefficient μ ₀ , which acts on the Reibflächenpaarung are tuned such that circumferential forces are exceeded due to the inertia between the synchronizing body and the synchronizer ring when the transmission input shaft at a speed below the idle speed n _{L of} the drive motor rotates. This ensures that the damping and thus the friction between the synchronizing body and the synchronizer ring takes place mainly when passing through the idling speed.

Fig. 13d.) Shows the behavior of a motor vehicle drive train according to FIG. 13c.), However, was dispensed with the elastic energy storage. Consequently, the gearbox side coupling half is rigidly coupled to the transmission input shaft. Significantly, there is an increase in structure-borne noise emission with decreasing speed of the drive motor.

In further embodiments, instead of the shown Spring force for applying the normal force to the contact surfaces or friction surfaces of the damping device and a magnetic force a permanent magnet, an electromagnetic force that Depending on the speed is controlled / regulated or a force As a result of centrifugal force find application.

The described embodiments are only exemplary embodiments. A combination of described features for different embodiments is also possible. Further, in particular not described Features of the invention are part of the device, are the geometries shown in the drawings of To remove device parts.

Claims (5)

1. Motor vehicle drive train, in which a drive shaft of a drive motor, a coupled thereto via a clutch transmission input shaft of a countershaft, a driven by this differential and driven by this Radantriebswellen are arranged in a common region, wherein the countershaft transmission comprises at least one synchronizer, characterized in that the synchronizing device has at least one damping device which acts in the circumferential direction and in that the drive shaft is connected in a rotationally fixed manner to a coupling half of the coupling which is on the drive motor side. 2. Motor vehicle drive train according to claim 1, characterized in that the damping device comprises a synchronizing body ( 16 ) having a first contact surface ( 20 or 20 ') and at least one synchronizer ring ( 14 or 15 ) with a second contact surface, wherein the two contact surfaces a Form friction surface pairing. 3. Motor vehicle drive train according to claim 2, characterized, that at the Reibflächenpaarung by means of a spring force a Normal force works. 4. Motor vehicle drive train according to one of the preceding characterized, that a gearbox side coupling half of the clutch limited by means of an elastic energy storage rotatably supported against the transmission input shaft is. 5. A method for noise reduction in a motor vehicle drive train according to claim 2 or 3, characterized in that at the Reibflächenpaarung with a static friction coefficient μ _0, the normal force F _n is applied, wherein a factor μ ₀ .F _n of circumferential forces between the synchronizing body ( 16 ) and the Synchronizer ring ( 14 or 15 ) is exceeded when the transmission input shaft rotates at a speed below the idle speed n _{L of} the drive motor.