DE102007030091A1 - Drive train for motor vehicle, has driving motor, propelled axis with axle drive unit over which axle drive power is fed in side shafts - Google Patents

Abstract

The drive train has a driving motor (1), a propelled axis with an axle drive unit (2) over which the axle drive power is fed in side shafts (3,4). The axle drive unit has an axle drive body (5) which is coupled with the side shafts over shiftable side shaft clutches (6,7). The discontinuation of the drive power influence is ensured as determined by operating the side shaft clutch.

Description

• – einem Antriebsmotor,
• – wenigstens einer angetriebenen Achse mit einer Achsantriebseinheit, über die die Achsantriebsleistung in Seitenwellen eingeleitet ist, wobei die Achsantriebseinheit zumindest einen Achsantriebskörper umfasst, der über eine schaltbare Seitenwellenkupplung mit den Seitenwellen gekoppelt ist, um die Höhe der Antriebsleistung selektiv steuerbar in die Seitenwellen einzuleiten und/oder um unterschiedliche Drehzahlen der Antriebsräder zu ermöglichen,
• – und mit einem zwischen der Achsantriebseinheit und dem Antriebsmotor angeordneten schaltbaren Getriebe zur fahrzustandsabhängigen Wandlung der Drehzahl des Antriebsmotors auf eine Drehzahl des Achsantriebskörpers, wobei bestimmungsgemäß eine weitestgehende Unterbrechung des durch das schaltbare Getriebe geführten Antriebsleistungsflusses für einen Schaltvorgang und/oder zum Anfahren und/oder Anhalten vorgesehen ist.

The invention relates to a drive train of a motor vehicle with

• A drive motor,
• At least one driven axle having an axle drive unit via which the axle drive power is introduced into side shafts, wherein the axle drive unit comprises at least one axle drive body which is coupled to the side shafts via a switchable side shaft coupling to selectively drive the height of the drive power into the side shafts and / or or to allow different speeds of the drive wheels,
• - And with a arranged between the final drive unit and the drive motor switchable transmission for driving state-dependent conversion of the speed of the drive motor to a speed of Achsantriebskörpers, where intended a substantial interruption of guided through the switchable transmission drive power flow for a switching operation and / or for starting and / or stopping is provided.

in the The prior art is a drive train of the aforementioned Type for driving a secondary axis of a Motor vehicle known.

drive motors are usually internal combustion engines, especially reciprocating engines, But also by electric motors, hybrid drives, Fuel cells or other engines are formed.

Axial drive units usual Motor vehicles are standard by form-fitting working differentials formed, which makes a speed compensation between two drive wheels of a driven axle when cornering to enable. This is especially to avoid Tension in the drive train and thereby excessive Tire wear. The mentioned axle drive units comprise also an axle drive body, over which the drive power is transmitted to the side shafts. An example of this is the differential carrier of a differential.

The switchable gearbox ensure the driving condition dependent Conversion of the speed and the drive torque of the drive motor at a speed and a moment of the transmission downstream Part of the drive train right up to the drive wheel. At switching and Stopping operations is the drive power flow that passes through the gearbox is routed to interrupt by disengaging to allow the insertion or change of the gear or to the death of the engine when falling below a minimum speed to prevent. When starting is the interrupted power flow to build up by engaging.

in the Contrary to the aforementioned common powertrain designs have already been developed drive trains in which no positive-locking differential gear, but differentialless, at least partially frictionally engaged axle drive units be used. A belonging to the final drive unit Axle drive body, via a transmission output shaft or over a propeller shaft is driven, it drives over two Friction clutches the separate side shafts of a driven Secondary axis on. By loosening - partially or completely - or blocking the side shaft couplings and an appropriate regulation can be over introduced the final drive body in the drive axle Distribute drive power specifically to the two side shafts. The basic function of a differential gear leaves thus about such a differential axis drive unit depict what previously, however - as described above - only in secondary axes, but not in the primary driven axle has been realized. Besides that is an influence on the driving dynamics through targeted application of Yaw moments possible, so in critical driving situations a targeted intervention in the driving dynamics carried out can be.

Such a drive train of the aforementioned type is for a four-wheel drive vehicle in the DE 40 21 747 02 disclosed. A drive unit drives a main drive shaft, which is connected via a differential and an intermediate gear to the drive unit. Furthermore, the drive unit drives a second drive axle, which has two side shafts, which are connected via a double clutch to an axle drive body of an axle drive unit. The dual clutch can be actuated via a regulating and control unit as well as an actuating device and can switch on the second secondary drive axle as a so-called "hang-on" axle of the main drive unit or primary axle if required.

From the DE 10 2004 046 008 A1 For example, a drive train is known in which a driven axle of the drive train is driven via a first and a second side shaft coupling, which are actuated essentially independently of one another. The two side shafts of the axle are each connected to one of the clutches and can be controlled by the individual control of the friction clutches such that the right or left drive wheel can be specifically assigned a specific moment. The axis driven by the side shaft couplings is a "hang-on" axle, which is only activated as a secondary axle if required.

Independently from the aforementioned functions and advantages of a final drive, where the side shafts of a driven secondary axis driven without a differential via clutch arrangements, require the above drive trains from the prior art still an additional Start-up or switching element with which the power flow through the switchable gearbox is leads, can be interrupted. This is the only way to change gear by engaging or disengaging made and startup or holding operations performed become.

By default this is one between the drive motor and the shiftable transmission arranged clutch provided, which is usually over in Footwell arranged foot pedals are disengaged can. For automatic transmissions and CVT transmissions, which also to the shiftable transmissions according to the present Are to be counted in the invention, hydraulic transducers are provided, where the transmitted torque from falling below At a certain speed only transmits a very small drive torque. However, for all types of transmissions is the need interruption of the performance of the transmission or torque flow given for certain operating situations.

As Every component on the motor vehicle causes these starting elements or clutches but additional vehicle weight, rotating mass, manufacturing and assembly costs, expenses related on spare parts and procurement logistics as well as design and construction Development effort. In addition, they are in case of repair by their Arrangement between drive motor and shiftable transmission only very hard to access. In addition, they require partly considerable space, which in view of the constantly Complex becoming vehicle structure especially in the immediate Close to the engine becomes more and more valuable in terms of design.

It is therefore an object of the invention to provide a drive train of the beginning to provide this type, in particular for the drive of the primary driven main drive axle a vehicle in which a starting element or a clutch in the above-described classical arrangement between drive motor and switchable transmission can be dispensed with.

The The object of the invention is achieved in that the interruption the drive power flow as intended by Actuating the side shaft clutches guaranteed is.

The initially described arrangement of the starting element or the clutch in particular between the drive motor and gearbox has therefore historically evolved because the moments to be transmitted as opposed to engine and manual transmission to be transmitted via the drive wheels Moments are relatively smaller while the speeds are correspondingly larger are so well received by the drive power through friction clutches and can be transmitted and further in terms of Clutch temperatures is manageable. Both the translations of the shiftable transmission as well as a subsequent axle or differential ratio or other translation levels usually cause the drive torques of the Motor seen in the direction of the drive wheel rise significantly while the speed of the drive train components decreases.

Of the Waiver of the conventional arrangement of a starting or Coupling element creates additional space. transmission and engine can move closer together or the space available can be used for other purposes become. Because the differentialless final drive unit with the side shaft clutches can be made compact and all functions a conventional balancing or transfer case can be realized by the differential axis drive unit, is compared to a conventional powertrain no additional space required. The conventional one Differential can be eliminated and by a differentialless final drive unit be replaced. In automatisier ter actuation of the side shaft clutches In addition, a part of the pedals in the footwell of the driver omitted.

The individual activation of the side shafts via is made possible by means of an respectively assigned selectively activatable region of the side shaft coupling. By unequal distribution of the drive torques guided on the drive wheels of a drive axle, a targeted yaw moment of the vehicle can be built up. whereby the driving dynamics of the vehicle can be selectively influenced. Thus, conventional electronic stability programs, which correctively intervene by deliberately braking individual wheels in critical driving situations, can be supplemented or even replaced. In contrast to acting on the braking effect of the vehicle brakes stability program, the driver is supported by the targeted distribution of the drive power. The same basic idea of the targeted selective drive power distribution can of course also be realized in overrun mode, if this can be specifically directed to individual drive wheels through targeted distribution, for example of the engine braking torque. By completely closing both clutches, the properties of a 100% locked axle can be mapped, thus achieving maximum traction potential. It can be the function of a transverse lock imaged the.

When crossing the traction potential of a drive wheel can be by opening the drive power transmitted Side shaft coupling the drive torque to the transferable Reduce traction potential, so that at any time an optimal Starting off on the respective underground can be realized. By an appropriate scheme can thus be in a simple Way a traction control to prevent the slipping of the Mapping wheels.

opposite The function of a classic differential is no torque compensation Instead, there is a targeted assignment of a desired torque on a drive wheel. This results in a more optimal utilization the traction potential.

As well can with the differential axis drive unit speed differences the individual wheels, which are approximately through different radii of curvature the driven wheels or caused by the steering angle be compensated by specifically approved slippage. Due to the inventive design of the drive train is thus both the differential as such and the starting elements or clutches superfluous, what the input mentioned disadvantages of the need for a switching and starting element avoids and in particular cost advantages, weight savings and improved Functionality brings with it.

At usual Powertrain regulations become in overrun - the driver goes off the gas while driving - becomes the engine towed by the rolling vehicle. This leads to the vehicle is relatively fast slowed down. To make the kinetic energy of the vehicle not faster to dissipate as desired by the internal friction in the drive train, Automated decoupling strategies have been developed in which be decoupled during coasting engine and transmission, so that the Engine idling continues and the vehicle without passing through the Motor friction to be braked continues to roll. An improvement Aspect of these strategies is that the rotationally fixed with the drive wheels connected gear but still from the drive train with be hauled high speed and thus, especially in automatic transmissions with hydro-converter, still undesirably high power losses, in particular punch losses, incurred, which makes the vehicle unnecessary delay. If, however, a powertrain is used, in the drive motor and gear rotatably connected to each other are and the decoupling of the transmission from the drive wheels takes place behind the transmission, the gearbox also turns in overrun mode with the idling speed of the drive motor, giving the power loss of the drive train in overrun significantly reduced.

in principle can the side shaft coupling of one in a single component be formed clutch unit, the two from each other includes independent controllable coupling areas, for example two in a Lammellenkupplungsgehäuse separated from each other controllable plate packs. However, a first side shaft coupling is preferred, to drive the left drive wheel with the left side shaft cooperates, and a second side shaft coupling, which is to drive the right drive wheel interacts with the right side shaft, intended. Preferably, therefore, form both side shaft clutches separate, however more preferably identically designed components.

In Another possible embodiment drives the Achsantriebskörper the side shafts indirectly via an intermediate gear. In particular, the intermediate gear can the side shaft clutches be downstream. About the translation of this Intermediate gearbox can on the through the side shaft clutches to be transmitted drive torque or drive speeds Be influenced to adapt to the clutch IDs. This ensures that the side shaft couplings the Drive power can transmit. This measure is particularly suitable for vehicles with rear-wheel drive, whose driven rear wheels through the dynamic weight shifting have an increased traction potential when accelerating.

Prefers come as side shaft clutches multi-plate clutches are used in particular, it may be provided that the axle drive body at least partially by a plate carrier of the Lammellenkupplung, in particular by the outer disk carrier formed is. This leads to a particularly compact design of the Final drive.

Also considered as belonging to the invention is the use of an axle drive unit for the intended interruption of guided through a switchable transmission drive power flow for a switching operation and / or for starting the motor vehicle, the final drive unit is designed to initiate a final drive power in side shafts of a driven axle of a motor vehicle and the Achsantriebseinheit comprises a final drive body which cooperates via at least one switchable side shaft coupling with side shafts of the driven axle to selectively initiate the amount of drive power controllable in the side shafts and / or at different speeds of the to enable drive wheels.

The aforementioned advantageous embodiments of the drive train may apply mutatis mutandis to the use the final drive unit to be transferred. Is preferred also when using the final drive unit, a side shaft coupling each side wave provided.

Further Features and advantages of the invention will become apparent from the dependent claims and from the following description of preferred embodiments based on the drawings.

In the drawings shows:

1 a typical arrangement of a drive train according to the prior art,

2 the drive train 1 wherein the function of the starting element is provided by a differential-free axle drive unit arranged in an external housing,

3 the drive train 2 wherein the differentialless final drive unit shares a housing with the transmission for more compact design,

4 the drive train according to 3 in which the released space is used to dispose a hybrid disk,

5 the drive train of a rear-wheel drive motor vehicle with longitudinal front engine according to the prior art and the schematic illustration of a conventional bevel gear, and

6 a drive train according to 5 wherein the rear axle differential is formed by a differentialless final drive unit.

1 shows in sketchy the typical arrangement of a drive train of the motor vehicle according to the prior art. A drive motor 1 is about a conventional starting element 12 with a switchable gearbox 9 connected, whose housing 10 on the drive motor 1 is flanged. The output shaft 11 of the shiftable transmission 9 drives a Vorderachsdifferential, with which the left side wave 3 and the right side wave 4 interact. The side waves 3 . 4 are in turn connected to a driven by them each drive wheel (not shown). The decoupling of the drive motor 1 and the transmission 9 is due to the conventional starting element 12 guaranteed. In the 1 shown drive train arrangement corresponds to that of a front-wheel drive with transversely mounted drive motor 1 , However, the invention can basically be applied to all powertrain concepts, including four-wheel drive trains.

2 shows that as opposed to 1 modified version, with the still in 1 illustrated conventional starting element 12 is waived. The gear of the transmission 9 necessary drive power interruption is due to the switchable side shaft clutches 6 . 7 guaranteed. The conventional starting element 12 , this in 1 is still shown, is therefore unnecessary.

As the side shaft couplings 6 . 7 are in the figures with respect to the drive torque at the side shaft level, so in particular for the low gears must absorb a high torque, they are dimensioned so that they can transfer the entire level of performance to the drive wheels at any time. In all embodiments, virtually wear-free multi-plate wet clutches are preferably used.

The drive motor in 2 drives over the illustrated transmission 9 an axle drive unit 2 on, in addition to the side shaft couplings 6 . 7 an axle drive body 5 includes, over the side shaft couplings 6 . 7 with the side waves 3 . 4 interacts. The final drive body 5 is preferred via a positive toothing of the transmission output shaft 11 driven.

transmission 9 and final drive unit 2 are in two interconnected housings, a transmission housing 10 and a clutch housing 13 arranged, wherein in the transmission housing 10 arranged axle drive body 5 a hollow shaft 14 forms, which are torsionally rigid with a single drive element of the clutch 6 . 7 connected is. The side waves 3 . 4 In turn, with the output elements of the clutches 6 . 7 rotatably connected. The respective side waves 3 respectively. 4 assigned coupling areas 6 respectively. 7 can be controlled and switched separately.

The in 2 illustrated by the dashed line area limits the space savings by eliminating the in 1 still used conventional starting element 12 represents.

In contrast to 2 is in 3 the entire final drive unit with the transmission housed in a single housing, resulting in an even more compact drive train assembly. The drive body 5 is here directly as a clutch drive element, namely, for example, as an outer-plate carrier of a multi-plate clutch executed. Other coupling designs are also conceivable and the invention is not limited to a multi-plate clutch.

4 illustrated with the arrangement of components of a hybrid drive, in particular a hybrid disc 15 , in the installation space, in which 1 According to the prior art, a conventional starting element 12 is arranged, a significant advantage of the invention. By eliminating the classic arrangement of the conventional starting and coupling element 12 out 1 becomes space free, as in 4 illustrated for the more popular hybrid units can be used. Of course, the space can also be exploited by other measures. Thus, estimates show that by eliminating a conventional starting element 12 newly available space with otherwise identical space allocation and dimensioning of a drive unit 1 is sufficient to expand a reciprocating engine by a cylinder. Independent of this, additional space can be created for ancillaries and the freedom of the designer can be increased.

5 and 6 show in contrast to the 1 to 4 the powertrain of a rear-wheel drive vehicle.

In 5 is a conventional starting element according to the conventional construction of such a drive train 12 provided that between a switchable transmission 9 and the drive motor 1 is arranged. The transmission output shaft 11 is via a propshaft 16 Connected to the rear differential that the drive power in a known manner to the two side shafts 3 . 4 the rear axle forwards. The rear axle differential is in the right part of 5 sketchy and exemplified as a bevel gear differential. The decoupling of the drive motor 1 and the transmission 9 is in the drive train according to 5 by the conventional starting or coupling element 12 guaranteed.

6 shows the drive train 5 , wherein the function of the conventional starting element 12 through the differentialless final drive unit 2 is realized, so that in 5 shown conventional starting element 12 can be omitted. The space to be saved thereby is through the in 5 dotted line indicated. In the right part of 6 is the differentialless final drive unit 2 shown enlarged.

While at the 2 and 3 illustrated embodiments of the final drive unit 2 the side shaft couplings 6 . 7 immediately next to each other and on one side of the drive body 5 are trained in is 6 a version with two spatially separated side shaft couplings 6 . 7 intended. The one from the cardan shaft 16 driven final drive body 5 located between the side shaft couplings 6 . 7 , Also conceivable are embodiments in which an axle drive body is formed by two separate components which are both driven by the transmission output shaft or the cardan shaft. In this case, a separate axle drive body is provided for each side shaft or side shaft coupling. However, these various arrangements are independent of the specific embodiments and can basically be selected for each drive train arrangement.

Regardless of the respective illustrated by the figures concrete embodiments in which the coupling axes of rotation substantially coincide with the side shaft rotation axes, other design are conceivable. The axes of rotation of the side shaft couplings 6 . 7 For example, with the axis of rotation of a propeller shaft 16 or a transmission output shaft 11 coincide or at least substantially aligned parallel to these. In one of the side shaft clutches 6 . 7 downstream intermediate gear (not shown), the axes of rotation of the side shaft clutches 6 . 7 also offset parallel to the axes of rotation of the sideshafts 3 . 4 be when about clutch output side, a gear rotatably to a side shaft coupling 6 . 7 is arranged that the drive power via a rotationally fixed to a side shaft 3 . 4 arranged gear transmits to the side shaft. With a corresponding ratio, the torque to be transmitted through the side shaft clutches can be reduced while at the same time the clutch speed is increased, which can also have a positive influence on the controllability of the clutches.

The required for the clutch actuation actuator (not shown) may be formed by known clutch actuation devices. These include in particular hydraulic, electromagnetic, pneumatic or purely mechanical methods. Preferred is for each side shaft coupling 6 . 7 a separate actuator provided. By appropriate control of the actuator, it is possible to drive each 8th selectively, ie to control individually and to impose the drive power. Depending on the characteristic curve of the clutches, the permitted clutch slip can be applied to a side shaft 3 . 4 and thus on a drive wheel 8th transferred power to be adjusted.

For controlling or regulating the side shaft clutches 6 . 7 the data stored in a control unit and the travel data recorded by sensors are used. These include, for example, steering angle, speed of various components, in particular those of the side shafts and the drive body, axle geometries and calculation algorithms.

The torque control of the side shafts or the drive wheels during driving can be done both as "μ _low-control " and "μ _high-control ". The first type of control essentially forms the function of an open differential, in which the torque transmittable on the drive wheel of an axle is directed toward the wheel with the lowest traction potential with regard to a torque balance on the drive wheels of the axle. By contrast, the latter control variant depicts the behavior of a limited-slip differential.

1

drive motor

2

final drive

3

left sideshaft

4

right sideshaft

5

Achsantriebskörper

6

first Side shaft coupling

7

second Side shaft coupling

8th

drive wheel

9

switchable transmission

10

gearbox

11

Gearbox output shaft

12

conventional Starting or coupling element

13

clutch housing

14

hollow shaft

15

hybrid disc

16

propeller shaft

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 402174702 [0007]
• DE 102004046008 A1 [0008]

Claims (7)

Drive train of a motor vehicle with - a drive motor ( 1 ), - at least one driven axle with an axle drive unit ( 2 ), via which the final drive power in side shafts ( 3 . 4 ), wherein the axle drive unit ( 2 ) at least one axle drive body ( 5 ), which via a switchable side shaft coupling ( 6 . 7 ) with the side shafts ( 3 . 4 ) is coupled to the amount of drive power selectively controllable in the side waves ( 3 . 4 ) and / or at different speeds of the drive wheels ( 8th ), and with one between the final drive unit ( 2 ) and the drive motor ( 1 ) arranged switchable transmission ( 9 ) for driving state-dependent conversion of the rotational speed of the drive motor ( 1 ) to a speed of the shiftable transmission ( 9 ) subordinate part of the drive train, whereby intended a most extensive interruption of the through the switchable transmission ( 9 ) provided drive power flow for a switching operation and / or for starting and / or stopping, characterized in that the interruption of the drive power flow intended by operating the side shaft coupling ( 6 ) is guaranteed. Drive train according to claim 1, characterized in that a first side shaft coupling ( 6 ) for driving the left drive wheel with the left side shaft ( 3 ) and a second side shaft coupling ( 7 ) for driving the right drive wheel with the right side shaft ( 4 ) is provided. Drive train according to one of the preceding claims, characterized in that the axle drive body ( 5 ) drives the side shafts indirectly via an intermediate gear. Drive train according to claim 3, characterized in that the intermediate gear is the side shaft clutches ( 3 . 4 ) is connected downstream. Drive train according to one of the preceding claims, characterized in that the side shaft coupling ( 3 . 4 ) is formed by a multi-plate clutch and the final drive body ( 5 ) is at least partially formed as a plate carrier. Drive train according to one of the preceding claims, characterized in that between the drive motor ( 1 ) and switchable transmission ( 9 ) Components of a hybrid drive, in particular a hybrid disc, are provided. Use of an axle drive unit ( 2 ) for the intended interruption of the by a shiftable transmission ( 9 ) guided drive power flow for a switching operation and / or for starting the motor vehicle, wherein the axle drive unit ( 2 ) for initiating a final drive power in side shafts ( 3 . 4 ) is formed of a driven axle of a motor vehicle and the axle drive unit ( 2 ) comprises an axle drive body, which via at least one switchable side shaft coupling ( 6 . 7 ) with side waves ( 3 . 4 ) of the driven axle cooperates to selectively control the amount of drive power in the side shafts ( 3 . 4 ) and / or to allow different speeds of the drive wheels.