motor vehicle

Abstract

Motor vehicle with a drive train (1) comprising a drive (2), a drive shaft (3), a rigid axle (4) comprising an axle body (5), a transmission (7) and at least one axle shaft (6), wherein the transmission (7) and the axle shaft (6) are arranged in the axle body (5), characterized in that the drive shaft (3) is designed as a jointless shaft and the drive (2) is rotatably mounted on the body of the motor vehicle about an axis of rotation (8) which in intended use is aligned parallel to a transverse direction of the vehicle, in order to be able to follow spring movements of the rigid axle (4) by means of rotation.

Description

[0001] The present invention relates to a drive train for a motor vehicle of the type defined in more detail in the preamble of claim 1. Furthermore, the invention relates to a motor vehicle of the type defined in more detail in preamble 14.

[0002] From DE 10 2010 012 115 A1, a drive train for a single wheel of a motor vehicle is known, in which a drive in the form of an electric machine is articulatedly mounted to the body of the motor vehicle. The electric machine is connected to a wheel hub by means of a short drive shaft. The wheel hub is also articulatedly mounted to the body by means of a linkage arrangement.

[0003] The disadvantage here is that the wheel carrier is mounted via a complex and costly linkage arrangement, and a separate drive is required for each wheel of a motor vehicle with this drivetrain.

[0004] The object of the present invention is therefore to propose a drive train and a motor vehicle that overcome the aforementioned disadvantages.

[0005] The problem underlying the invention is solved by the features of independent claims 1 and 14. Further advantageous embodiments are described in the dependent claims and the drawings.

[0006] A drivetrain for a motor vehicle is proposed, comprising a drive unit, a drive shaft, and a rigid axle. The rigid axle, in turn, has an axle housing in which a transmission and at least one axle shaft of the drivetrain are arranged.

[0007] According to the invention, it is proposed that the drive is rotatably mounted about an axis of rotation which, in its intended use, is aligned parallel to a transverse direction of the vehicle.

[0008] On the one hand, the rigid axle eliminates the need for the aforementioned complex multi-link suspension for wheel mounting. On the other hand, the rotatable mounting of the drive unit around an axis of rotation parallel to a transverse direction of the vehicle allows two wheels on the same axle to be driven by the drive unit. Furthermore, the rotatable mounting offers the advantage that, if the drive unit is mounted on the body of a motor vehicle, it can, for example, follow the spring movements of the rigid axle by rotating it. This reduces the requirements for the flexibility of the drive shaft. The intended use of the drive train, in this context, means that the drive train serves to propel a motor vehicle.

[0009] In this context, the transverse direction of the vehicle refers to the direction along a motor vehicle in which, for example, the vehicle's axles run. Perpendicular to this is the longitudinal direction of the vehicle, in which the vehicle moves when driving straight ahead under normal operating conditions. The axis of rotation is, for example, parallel to the rigid axle.

[0010] The axle housing, for example, is a solid and rigid casing for accommodating the axle shaft and the gearbox. The drive shaft and the axle shaft are arranged essentially perpendicular to each other. The gearbox, for example, serves as the connecting element between the drive shaft and the axle shaft. The drive shaft may also be housed in a rigid casing. This rigid casing may serve to transmit relative movements of the rigid axle to the drive.

[0011] At the wheel-side ends of the rigid axle or axle housing, wheel carriers and possibly wheel hubs for mounting wheels are arranged. The axle housing, in particular, provides a rigid connection between the wheel carriers on both sides. The drivetrain as a whole is designed to transmit torque generated by the drive via the drive shaft, the transmission, and the axle shaft to the wheels.

[0012] The axle shaft can be divided by the transmission into a first axle shaft section and a second axle shaft section. For example, the first axle shaft section and the second axle shaft section can move independently of each other. The first axle shaft section, for example, drives a first wheel, and the second axle shaft section drives a second wheel.

[0013] It is advantageous if the rigid axle is designed as the rear axle. Rear axles are usually driven via several transmissions and a driveshaft that spans a large portion of the vehicle's length. The drivetrain according to the invention is significantly more compact for driving a rear axle. The resulting space savings can be used elsewhere, for example, for a battery. The drivetrain can be the sole propulsion system of a motor vehicle as a rear axle drive. However, it is also conceivable that the drivetrain is part of an all-wheel drive system. In this case, the drivetrain can, for example, operate independently of any other drivetrain of the motor vehicle. Due to its increased stability, the rigid axle is particularly suitable as a rear axle for commercial or off-road vehicles.

[0014] Furthermore, it is advantageous if the drive shaft is designed as a jointless shaft. In contrast to conventional cardan shafts, which, for example, have at least one universal joint, joints are omitted here. By eliminating joints, the drive shaft can be manufactured more cost-effectively. Likewise, the absence of joints results in less wear on the drive shaft. In addition, the jointless drive shaft can potentially transmit higher maximum torques. The inventive bearing arrangement of the drive makes it possible to use a jointless shaft as the drive shaft in the first place. The drive can follow the spring movements of the rigid axle through rotation. Additional degrees of freedom for the drive shaft are not necessarily required.

[0015] Preferably, the movements of the rigid axle are transmitted to the drive via a rigid housing in which the drive shaft is arranged. This means that the transmission of these movements does not occur, or at least not primarily, via the drive shaft, which is consequently subjected to lower mechanical loads.

[0016] It is particularly advantageous if the drive's center of gravity is located on the axis of rotation. This prevents additional restoring forces from occurring during rotation. As a result, the drive can rotate with minimal resistance and thus does not significantly restrict the rigid axle's freedom of movement. When the drive train is in its intended use and the rigid axle is stationary, the drive's center of gravity is located, for example, at the same height as the rigid axle. The drive can, for instance, be housed in a substantially cylindrical casing.

[0017] Furthermore, it is advantageous if the transmission is designed as a differential or transfer case. A differential, for example, allows a first axle shaft section and a second axle shaft section to rotate at different speeds, while still transmitting the drive torque to both axle shaft sections. This, in turn, allows the drivetrain to corner without necessarily losing traction at one wheel. The axle shaft sections are nevertheless coupled by the transmission. A transfer case is a transmission that can additionally distribute the drive torque to the first and second axle shaft sections in varying proportions, depending on the requirements. Such torque distribution is particularly advantageous for the handling of a vehicle. The transfer case can, for example, be electronically controlled.In the case of two axle shaft sections, the axle shaft sections are coupled by the gearbox.

[0018] It is particularly advantageous if, in normal use, the drive unit is positioned longitudinally between a front axle and a rear axle. This allows for the utilization of the installation space created by the absence of a driveshaft (see above). The exact position of the drive unit can be varied depending on the desired mass distribution of the vehicle.

[0019] Another major advantage is that the drivetrain can be mounted on the vehicle body. When the drivetrain is mounted on the vehicle body, it is wholly or at least partially integrated into the vehicle's sprung mass. This improves the vehicle's handling and ride comfort.

[0020] In principle, various compact motors are conceivable for the drive system. However, it is particularly advantageous if the drive system incorporates an electric motor. Electric motors are characterized by high maximum power output in a compact design and can be easily powered via cables. Various electric motor designs are possible. For example, the electric motor can be a permanent magnet or separately excited DC motor, or even a reluctance motor. The drive system can also include, for example, a motor gearbox, which may offer different gear ratios.

[0021] According to a further advantageous embodiment of the drive train, at least one spring assembly, in particular at least one leaf spring, is assigned to the axle housing. The spring assembly, for example, establishes a connection to the vehicle body. This provides a certain degree of vibration isolation between the body and the rigid axle. This reduces the mechanical stress on the body and any components that may be located within the body, for example, when driving over uneven road surfaces. For example, two spring assemblies are arranged on the axle housing. The spring assemblies are arranged, in particular, near the wheel carriers or the wheel-side ends of the rigid axle and are spaced apart from each other in a mirror-symmetrical manner.

[0022] A leaf spring can absorb particularly high loads and is therefore especially suitable for commercial and off-road vehicles. The leaf spring can, for example, consist of several individual leaves arranged one above the other, which may have different lengths. In this case, friction between the leaves also results in a certain damping effect. In addition to its spring and damping functions, at least one leaf spring can advantageously also perform the function of wheel guidance. This can be achieved by mounting the axle beam against the vehicle's body and / or subframe via two parallel leaf springs aligned longitudinally with the vehicle.

[0023] Alternatively or additionally, the axle assembly can be mounted so that it is vertically movable relative to the vehicle's body and / or subframe by means of a linkage arrangement, preferably longitudinal control arms and a Panhard rod. In this case, the axle assembly is also expediently equipped with a spring and / or damping system.

[0024] Advantageously, in the intended use of the drivetrain, the drive shaft runs essentially parallel to the vehicle's longitudinal direction. The drive shaft's path is similar to that of a conventional cardan shaft, for example. Therefore, conventional components and methods can be used for manufacturing and assembling the drive shaft. In particular, a gearbox with a standard connection for the shaft can be used. Furthermore, sufficient installation space is usually available in the vehicle's longitudinal direction for arranging the drive shaft. It is understood that the drive shaft's path can be temporarily altered by the movement of the rigid axle's suspension from a neutral to a deflected position.

[0025] In an advantageous embodiment of the drivetrain, the drive is mounted by rubber bearings, preferably by two rubber bearings, particularly relative to a vehicle body or subframe. Rubber bearings are generally characterized by the fact that, for example, a rotary bearing is arranged in an elastomer, which in turn is surrounded by a bushing, for example, made of metal. The elastomer allows for minor movements of the rubber bearing in additional degrees of freedom, besides the primary rotational degree of freedom of, for example, a rotary bearing. Additionally, the elastomer dampens vibrations. The two rubber bearings define, for example, the axis of rotation about which the drive is rotatably mounted. In addition to rotation, the rubber bearings also allow, for example, minor translations of the drive, which lead to a reduction in the mechanical stresses during movements of the rigid axle.The rubber mounts also acoustically decouple the drive unit from the vehicle body. This significantly reduces the transmission of vibrations between the drive unit and the body. The rubber mounts preferably have a rotational degree of freedom as their primary degree of freedom. For example, the rubber mounts are located at the same height as the drive unit's center of gravity.

[0026] Furthermore, it is advantageous if the rubber mounts are arranged on a mounting device, particularly one that can be attached to the vehicle's body or subframe. Such a mounting device can, for example, be in the form of a bracket that can be attached to the vehicle's body or subframe at each end and has an eyelet in a curved section for receiving a rubber mount. Compared to a solid bracket, the bracket saves material and weight. The bracket is, for example, designed as a curved tube with two mounting points for attachment to the vehicle's body. The rubber mount is, for example, arranged in a corresponding receptacle at a bend in the tube. The bracket(s) define the maximum range of motion of the drive unit, for example, by the distance between the mounting points and the receptacle.

[0027] It is also advantageous if, in a top view, the drive and the drive shaft are arranged on a plane of symmetry, with the drivetrain being essentially mirror-symmetrical with respect to this plane of symmetry. This arrangement results in a uniform mass distribution in the transverse direction of the vehicle. This allows for simplified chassis tuning. Preferably, the transmission and, optionally, the center of the rigid axle are also located on the plane of symmetry.

[0028] The motor vehicle according to the invention, comprising a drivetrain, is characterized by the fact that the drivetrain is designed as described above. The aforementioned features can be present individually or in any combination. As already described, the rigid axle of the drivetrain can, for example, represent the rear axle of the vehicle. In this case, a conventional driveshaft spanning a large portion of the vehicle's length can be dispensed with. The drive is preferably mounted on a body of the motor vehicle and thus at least partially associated with the sprung mass of the motor vehicle. Due to the rotatable mounting of the drive, it can follow the spring movements of the rigid axle. A driveshaft may be omitted.

[0029] The powertrain can be the vehicle's sole means of propulsion or, for example, part of an all-wheel-drive system. A second axle of the vehicle can be driven in any way desired. For instance, an additional electric drive is conceivable. The main drive and the additional drive can share an energy supply, such as a battery, if the main drive uses an electric motor. It is also conceivable that the additional drive is a conventional engine, such as an internal combustion engine. In this case, the main drive can be powered by a generator, for example. The vehicle can be designed as a commercial vehicle or an off-road vehicle.

[0030] The invention is explained in more detail below with reference to the drawings. The drawings show: Fig. 1 an isometric view of a drive train according to the invention, and Fig. 2 a top view of the drive train according to the invention.

[0031] In the following description of the figures, the same reference symbols are used for features that are identical and / or at least comparable in the various figures. The individual features, their design, and / or mode of action are usually only explained in detail upon their first mention. If individual features are not explained again in detail, their design and / or mode of action corresponds to the design and mode of action of the already described features with the same or identical effect.

[0032] The Fig. Figure 1 shows a drive train according to the invention. 1 , whereby the drivetrain 1 The drivetrain is basically designed according to the preceding description. 1 includes a drive 2 , a drive shaft 3 and a rigid axle 4 with an axle body5 . In the axle body 5 are an axle shaft 6 and a gearbox 7 arranged. A section of the axle body 5 This can, for example, be designed as a gearbox housing. The drive 2 is around an axis of rotation 8 rotatably mounted, which during normal use of the drive train 1 is aligned parallel to a transverse direction of the vehicle. The axis of rotation is also 8 also parallel to the rigid axle 4 (see Fig. 2).

[0033] At the wheel-side ends 9 the rigid axle 4 are bike carriers 10 Arranged for mounting wheels (not shown). Via the drive shaft 3 , the gearbox 7 and the axle shaft 6 A torque of the drive will be 2 transferred to the wheels and thus used as intended by the drivetrain 1a motor vehicle powered. If the drivetrain 1 used to drive a rear axle of the motor vehicle, the drive 2 and the drive shaft 3 for example, partially occupying the installation space of a conventional cardan shaft.

[0034] The drive 2 is provided by two rubber bearings 11 supported, which primarily allows rotation of the drive 2 enable. Furthermore, the rubber bearings allow for... 11 also movements of the drive 2 Possible in other degrees of freedom. The axis of rotation. 8 for example, by a connecting line between the two rubber bearings 11 given (see also here) Fig. 2) The rubber bearings 11 are present in each case in a bracket 12 arranged. The brackets 12 In this example, they are bent tubes, each with two mounting areas. 13Designed for attachment to the body of a motor vehicle. The rubber bearings 11 are, for example, in a corresponding recording at a bend in the bracket 12 arranged. A vertical distance between the rubber bearings. 11 and the fastening areas 13 is chosen in such a way that sufficient freedom of movement is allowed for the rotation of the drive. 2 consists.

[0035] The drive 2 for example, it is used as an electric drive 2 trained and has an electric motor 14 up. The gearbox 7 is designed, for example, as a differential gear that controls the torque of the drive 2 evenly distributed across the wheels, yet allowing for different angular velocities of the wheels. As already described, the transmission can 7but it can also be designed, for example, as a transfer case that assigns different torques to the wheels.

[0036] The drive shaft 3 is, for example, in a particularly rigid drive shaft housing 15 arranged. The drive shaft housing 15 It primarily serves to transmit forces between the rigid axle 4 and the drive 2 Furthermore, the drive shaft housing serves 15 also the protection of the drive shaft 3 from external influences. The drive shaft 3 It can, for example, be designed as a jointless shaft.

[0037] In this embodiment, the axle body 5 additionally two spring devices 16 on, which are designed as leaf springs. About the spring devices 16 is the rigid axle 4 connectable to the body of a motor vehicle. The spring devices 16They serve to isolate vibrations between the structure and the rigid axle. 4 .

[0038] On the bike racks 10 Examples include braking devices. 17 The braking devices are arranged to brake the wheels or the motor vehicle. 17 They can, for example, be designed as a combination of brake disc and brake caliper.

[0039] Fig. Figure 2 shows a top view of the drivetrain 1 out of Fig. 1. In this view, the geometric relationships of the individual elements are particularly easy to see. As already described, the axis of rotation 8 parallel to the rigid axis 4 The drive shaft 3 runs both towards the rigid axis 4 as well as to the axis of rotation 8 perpendicular. Overall, this results in an essentially T-shaped configuration of the drivetrain. 1 .

[0040] The powertrain 1is essentially mirror-symmetric about a plane of symmetry 18 built. The drive 2 and the drive shaft 3 are on the plane of symmetry 18 arranged. The gearbox is also 7 on the plane of symmetry 18 arranged. The spring devices 16 are also, in particular, mirror-symmetric about the plane of symmetry 18 spaced apart on the axle body 5 arranged.

[0041] The present invention is not limited to the embodiments shown and described. Modifications within the scope of the claims are possible, as is a combination of the features, even if these are shown and described in different embodiments. Reference symbol list 1 Powertrain 2 Drive 3 Drive shaft 4 rigid axles 5 axle bodies 6 axle shaft 7 gearboxes 8 Rotation axis 9 wheel-side end 10 bike carriers 11 rubber bearings 12 hangers 13 Mounting area 14 Electric motor 15 drive shaft housings 16 Spring assembly 17 Brake device 18 Plane of symmetry QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 102010012115 A1

[0002]

Claims

[1] Powertrain (1) for a motor vehicle with - a drive (2), - a drive shaft (3), - a rigid axle (4) comprising an axle body (5), - a gearbox (7) and - at least one axle shaft (6), wherein the transmission (7) and the axle shaft (6) are arranged in the axle body (5), characterized by , that the drive (2) is rotatably mounted about a rotation axis (8) which in its intended use is aligned parallel to a transverse direction of the vehicle. [2] Powertrain (1) according to the preceding claim, characterized by , that the rigid axle (4) is designed as a rear axle. [3] Powertrain (1) according to claim 1 or 2, characterized by , that the drive shaft (3) is designed as a jointless shaft. [4] Powertrain (1) according to any one of claims 1 to 3, characterized by , that a center of gravity of the drive (2) lies on the axis of rotation (8). [5] Powertrain (1) according to any one of claims 1 to 4, characterized by , that the transmission (7) is designed as a differential or transfer transmission. [6] Powertrain (1) according to any one of claims 1 to 5, characterized by , that the drive (2) is arranged in a longitudinal direction of the vehicle between a front axle and a rear axle when used as intended. [7] Powertrain (1) according to any one of claims 1 to 6, characterized by , that the drive train (1) can be mounted on a structure of the vehicle via the drive (2). [8] Powertrain (1) according to any one of claims 1 to 7, characterized by , that the drive (2) comprises an electric motor (14). [9] Powertrain (1) according to any one of claims 1 to 8, characterized by , that at least one spring assembly (16), in particular at least one leaf spring, is assigned to the axle body (5). [10] Powertrain (1) according to any one of claims 1 to 9, characterized bythat the axle body can be mounted in a height-movable manner relative to a superstructure and / or subframe of the vehicle by means of a linkage arrangement, preferably by means of longitudinal links and a Panhard rod. [11] Powertrain (1) according to any one of claims 1 to 10, characterized by , that the drive shaft (3) runs essentially parallel to the longitudinal direction of the vehicle during intended use. [12] Powertrain (1) according to any one of claims 1 to 11, characterized by , that the drive (2) is mounted by rubber bearings (11), in particular by two rubber bearings (1). [13] Powertrain (1) according to claim 12, characterized by that the rubber bearings (11) are arranged on each a fastening device, in particular in the form of a bracket (12). [14] Powertrain (1) according to any one of claims 1 to 13, characterized by, that in a top view the drive (2) and the drive shaft (3) are arranged on a plane of symmetry (18), wherein the drive train (1) is essentially mirror-symmetrical with respect to the plane of symmetry (18). [15] Motor vehicle with a drive train (1), characterized by , that the drive train (1) is designed according to one or more of the preceding claims.

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