Drive device for a four-wheel drive vehicle

Abstract

A drive device for an all-wheel drive vehicle has a drive unit (1) comprising a prime mover (11, 12) and a central shaft unit (20), as well as a first and a second portal transmission (30, 40). The central shaft unit (20) is operatively connected to the prime mover (11, 12) for receiving a drive force and has a first and a second central output element (21, 22) for outputting the drive force. The first and the second portal transmission (30, 40) are operatively connected to the drive unit (1) via the first and the second portal transmission (40) respectively for receiving the drive force. The first and the second portal transmission (30, 40) each have a portal output element (33, 43) which is operatively connected to a first and a second drive axle (71) via a first and a second transmission element (51, 52) respectively for outputting the drive force.The first and second portal output elements (33, 43) are each arranged offset in a direction relative to a rotational axis of the first and second central output elements (21, 22), respectively.

Description

Technical area

[0001] The present invention relates to a drive device for a four-wheel drive vehicle and a four-wheel drive vehicle. State of the art

[0002] Drive units for all-wheel-drive vehicles are well known. Adequate ground clearance is an essential feature for all-wheel-drive vehicles to avoid getting stuck off-road or to overcome larger obstacles. To provide sufficient ground clearance, the drive unit requires adequate space within the vehicle. Description of the invention

[0003] The present invention is based on the object of providing an improved electric drive unit for a vehicle with all-wheel drive, which has a small installation space and produces a higher ground clearance via its topology.

[0004] The object is achieved with a drive unit having the features of claim 1. Advantageous further developments are the subject of the dependent claims.

[0005] A first aspect relates to a drive device for an all-wheel drive vehicle. The drive device has a drive unit with at least one prime mover, a central shaft unit, a first portal gear, and a second portal gear. The all-wheel drive vehicle can be formed, for example, by a truck or other commercial vehicle. The all-wheel drive vehicle can be off-road. The all-wheel drive vehicle can be formed by a light, medium, or heavy all-wheel drive vehicle or a truck. The prime mover can be formed by at least one or more electric motors and a single- or multi-speed transmission. In addition, a differential or an engagement / disengagement device can be present on one of the two output sides.

[0006] The central shaft unit has a first central output element and a second central output element, each for outputting a drive force from the drive unit. The first central shaft element and the second central shaft output element may extend opposite to each other in a longitudinal direction of the four-wheel drive vehicle. The first central shaft element and the second central shaft output element may extend on opposite sides in the longitudinal direction with respect to the prime mover. The central shaft unit may have a plurality of shafts. Shafts may be hollow. Shafts may extend through other shafts. One of the shafts may be rotationally fixedly connected to the first central output element. One of the shafts may be rotationally fixedly connected to the second central output element. One of the shafts may be rotationally fixedly connected to the first and second central output elements.The central shaft unit is mechanically connected to the drive motor to receive drive power. One of a shaft of the central shaft unit, the first central output element, and the second central output element can be rotationally fixedly connected to a rotor shaft of the drive motor or the transmission.

[0007] The first portal transmission is mechanically operatively connected to the drive unit via the first central output element for receiving a drive force. The first portal transmission can be mechanically operatively connected to the first central output element via at least one of a single- or multi-speed transmission and a differential gear or a switching mechanism. The first portal transmission has a first portal output element which is mechanically operatively connected to a first drive axle via a first transmission element for outputting a drive force. The first transmission element can be formed by a rotary shaft or a propeller shaft. The first portal output element can be formed by a propeller shaft flange. The first portal output element can be formed by a splined shaft or a toothed shaft. The first drive axle can be formed by a front axle or a rear axle.The first drive axle can have several, for example two, output elements, such as drive wheels. The first drive axle can be formed by a steerable drive axle.

[0008] The second portal transmission is mechanically operatively connected to the drive unit via the second central output element for receiving a drive force. The second portal transmission can be mechanically operatively connected to the second central output element via at least one of a manual transmission (see first portal transmission) and a differential transmission.

[0009] The second portal transmission has a second portal output element, which is mechanically operatively connected to a second drive axle via a second transmission element for outputting a drive force. The first transmission element can be formed by a rotary shaft or a propeller shaft. The second portal output element can be formed by a propeller shaft flange. The second portal output element can be formed by a splined shaft or a toothed shaft. The second drive axle can be formed by a front axle or a rear axle. The second drive axle can have several, for example two, output elements, for example drive wheels. The second drive axle can be formed by a steerable drive axle.The drive device can have four drive wheels, with two drive wheels being provided on the first drive axle, for example the front axle, and two drive wheels being provided on the second drive axle, for example the rear axle; output to further axles by means of through-drive axles is also possible.

[0010] The first portal output element is offset in a direction to a rotational axis of the first central output element. The second portal output element is arranged in a direction offset in a direction to a rotational axis of the second central output element. This direction can be formed by the force of gravity. Since the drive unit is installed as high as possible but as low as necessary, the portals are oriented towards the ground here, although a slight lateral offset can also be advantageous if axles are used that have a laterally offset input. The respective portal output element can be offset downwards in the direction of gravity relative to the respective central output element. This direction can be transverse. The transverse direction can be oriented perpendicular to a direction of travel. The direction of travel can be longitudinal.The respective portal output element can be arranged offset from the respective central output element in the direction of gravity and in the transverse direction, obliquely downwards to the front or downwards to the rear. In this respect, the first portal gear and the second portal gear can each provide an offset direction and offset distance. The first portal gear and the second portal gear can provide the same offset direction and offset distance.

[0011] If two elements are mechanically operatively connected, they are directly or indirectly coupled to one another in such a way that a movement of one element causes a reaction in the other element. For example, a mechanical operative connection can be provided by a positive or frictional connection. The mechanical operative connection can correspond to the meshing of corresponding toothings of the two elements. Additional elements, such as one or more spur gear stages, can be provided between the elements. A permanently rotationally fixed connection between two elements, on the other hand, is understood to be a connection in which the two elements are rigidly coupled to one another in all intended states of the transmission. The elements can be present as individual components that are connected to one another in a rotationally fixed manner or as a single piece.A switching element, such as a clutch or brake, can be used to selectively establish or break a rotationally fixed connection between two elements.

[0012] The drive unit can have a drive housing. The first portal gear and the second portal gear can each have a portal housing. The respective portal output element can be arranged offset from the respective central output element in the offset direction such that an underside of the drive housing is aligned with an underside of at least one of the portal housings. The respective portal output element can be arranged offset from the respective central output element in the offset direction such that an underside of at least one of the portal housings projects downwards beyond an underside of the drive housing in the direction of gravity.

[0013] One of the first central output element and the second central output element can be configured as an output shaft. One of the first central output element and the second central output element can have a driving toothing, for example a splined shaft or a splined shaft.

[0014] One of the first portal gear and the second portal gear can have an output gear ratio of less than 1, greater than 1, or equal to 1. In this respect, one of the first portal gear and the second portal gear can have an output gear ratio that increases or decreases a speed. Both the first portal gear and the second portal gear can have an output gear ratio that decreases a speed. The first portal gear can have a first input gear and a first output gear. The second portal gear can have a second input gear and a second output gear. The respective output gear can have a greater number of teeth than the respective input gear. The respective input gear can mesh with the respective output gear. An output speed and tractive force of the drive device can be modularly optimized via the portal gear.

[0015] The respective input gear can be connected in a rotationally fixed manner to the respective central output element. The respective input gear can be arranged coaxially with the respective central output element. The respective input gear can be formed by the respective central output element. The first portal output element can be arranged coaxially with the second portal output element. The first portal output element can be designed symmetrically to the second portal output element in the longitudinal direction.

[0016] The portal output elements, which are offset in the offset direction, can provide high ground clearance. Furthermore, the joint angle can be kept small relative to the longitudinal direction. This allows for a compact design. This allows for installation space in the all-wheel-drive vehicle for vehicle components such as a battery or fuel cell components. This can improve the vehicle's range.

[0017] In one embodiment of the drive device, the first portal gear and the second portal gear can be arranged on opposite sides of the drive unit in the longitudinal direction. The first portal gear and the second portal gear can be designed symmetrically to each other in the longitudinal direction. The first portal gear and the second portal gear can have at least one of the same output gear ratio, the same gear type, the same offset direction, and the same gear structure.

[0018] In one embodiment of the drive device, at least one of the first portal gear and the second portal gear can be formed by a spur gear. Rotational axes of the respective portal output element and the respective central output element can be arranged in parallel. One of the first portal gear and the second portal gear can form a countershaft. The respective input gear and the respective output gear can each be formed by a spur gear. One of the spur gears can have external teeth. All of the spur gears can have external teeth. One of the spur gears can be designed as a ring gear. The respective input gear can be designed as a ring gear. The ring gear can have internal teeth. The first output gear and the second output gear can be formed by a ring gear. This can provide a small output gear ratio of less than 1.

[0019] In one embodiment of the drive device, at least one of the first portal gear and the second portal gear can be formed by a bevel gear. The respective input gear and the respective output gear can each have beveloid toothing. The axis of rotation of the respective portal output element can be inclined downwards in the direction of gravity with respect to the axis of rotation of the respective central output element. The axis of rotation of the respective portal output element can be aligned in the direction of a rotation axis of the respective transmission element. As a result, a bending angle between the respective transmission element and the respective portal output element can be designed to be small. This can provide a uniform rotational movement of the respective transmission element. Furthermore, a long service life of the transmission elements can be ensured.

[0020] In one embodiment of the drive device, at least one of the first drive axle and the second drive axle can be configured as a through-drive axle and can be mechanically operatively connected to another drive axle for outputting a drive force. The drive device can have another transmission element, for example, a rotary shaft or a cardan shaft, for outputting the drive force to the other drive axle. The through-drive axle and the other drive axle can form a double drive axle, for example, a double rear axle.

[0021] In one embodiment of the drive device, at least one of the drive axles can have a differential gear for driving two drive wheels. The differential gear can be configured to distribute the drive force between two drive wheels of one of the first drive axle and the second drive axle. The differential gear can have at least one of a bevel gear differential gear and a planetary gear differential gear. A differential gear can be connected upstream of one of the drive axles. The differential gear can have a gear ratio greater than 1, less than 1, or equal to 1.

[0022] In one embodiment of the drive device, the drive unit can have two drive motors that are mechanically operatively connected to the central shaft unit for outputting a drive force. The drive motors can be arranged coaxially with one another. Each of the drive motors can be formed by an electric motor. The two drive motors can be formed by two motors with separate windings. The two drive motors can have a common rotor shaft. The two drive motors can have a double rotor. The rotor shafts of the two drive motors can be coupled to one another, for example, mechanically operatively connected or rotationally fixed. The rotor shafts of the two drive motors can be coupled to one another via a summing gear. The two drive motors can be arranged within the drive housing.

[0023] In one embodiment of the drive device, the drive unit has a differential gear that is mechanically operatively connected to the drive engine for receiving a drive force and is mechanically operatively connected to the first portal gear and the second portal gear for outputting a drive force. The differential gear can have a gear ratio greater than 1, less than 1, or equal to 1. The differential gear can have a power distribution ratio, for example, between the first drive axle and the second drive axle of 50:50 or 1:2 and can be mechanically locked. At least one of the drive axles can be engaged via a switching element, for example as a front axle engagement. One of the drive axles can be engaged via a switching element, for example as a front axle engagement, without a differential gear. The differential gear can be arranged within the drive housing.The differential gear can be operatively connected to the drive engine via the central shaft unit. A rotating element, for example an input gear, of the differential gear can be rotationally fixedly connected to a shaft of the central shaft unit. The differential gear can have two output elements. The first central output element and the second central output element can each be rotationally fixedly connected to an output element of the differential gear.

[0024] In one embodiment of the drive device, the drive unit has a single-speed or multi-speed transmission which is mechanically operatively connected to the drive engine via the central shaft unit for receiving a drive force and is mechanically operatively connected to the first portal transmission and the second portal transmission for outputting a drive force.

[0025] The manual transmission may have one or more planetary gear sets. The manual transmission may have an input element, for example, a drive gear. The input element may be configured as a sun gear. The input element may be rotationally fixedly connected to the rotor shaft of one of the drive motors via the central shaft unit. The input element may be rotationally fixedly connected to the rotor shaft of one of the drive motors. The manual transmission may provide three selectable gear ratios. Each gear ratio may be associated with a gear that is selectable for the all-wheel drive vehicle and in which the all-wheel drive vehicle can be driven.

[0026] The manual transmission can be arranged longitudinally on the front of the drive engine. The manual transmission can be arranged longitudinally between the drive engine and the differential gear. The manual transmission can be arranged within the drive housing. The differential gear can be operatively connected to the manual transmission via the central shaft unit. The differential gear can be operatively connected to the drive engine via the central shaft unit and the manual transmission. A rotating element, for example an input gear, of the differential gear can be rotationally fixedly connected to a rotating element, for example an output gear, of the manual transmission. The manual transmission can be mechanically operatively connected to the first portal gear and the second portal gear via the central shaft unit.

[0027] The manual transmission can have two drive motors. The manual transmission can transmit power, for example, one of a speed and a torque, to the differential gear. The differential gear can be designed to be connectable to the manual transmission, for example, via a switching element.

[0028] The central shaft unit, or a shaft from the central shaft unit, can extend longitudinally, for example, from the differential gear or at least one of the drive motors forward through the manual transmission to the first portal gear and rearward to the second portal gear. The portal gears can ensure a torque and speed level of the vehicle optimized for a specific application via the axle ratios with all-wheel drive.

[0029] By appropriately selecting a gear ratio for at least one of the manual transmission, the differential, and the portal gears, an optimal spread for high speeds and high tractive forces can be provided. The gear ratios of the drive unit can be designed such that the drive unit and the portal gears can be mechanically connected to existing drive axles of existing all-wheel drive vehicles, for example, via appropriately designed transmission elements.

[0030] A second aspect relates to a vehicle, for example, a vehicle with all-wheel drive. The vehicle has a drive device according to the first aspect. Respective further features, embodiments, and advantages can be found in the descriptions of the first aspect. Conversely, features, embodiments, and advantages of the second aspect also represent features, embodiments, and advantages of the first aspect. The vehicle has at least four output elements. Two of the output elements can be driven by the first drive axle. The other two output elements can be driven by the second drive axle. The output elements can be driven by the drive engine of the drive device via at least one of the manual transmission and the differential gear. An output element can be designed as a wheel or a track. The vehicle can, for example, stand on a surface with the output elements. Short description of the characters Fig. 1 shows an embodiment of a drive device for a four-wheel drive vehicle. Fig. 2 shows schematically a detail of another embodiment of the drive device. Fig. 3 shows schematically a detail of another embodiment of the drive device. Fig. 4 shows schematically a detail of another embodiment of the drive device. Detailed description of embodiments

[0031] Fig. 1 shows an embodiment of a drive device for an all-wheel drive vehicle, for example, an off-road commercial vehicle. The drive device has a first drive axle 71, in this case a front axle, with a first differential gear 61, and a second drive axle 72, in this case a rear axle, with a second differential gear 62. Each of the first drive axle 71 and the second drive axle 72 has two drive wheels, which are driven via the corresponding differential gear 61, 62. The first drive axle 71 and the second drive axle 72 are aligned in a transverse direction and spaced from one another in a longitudinal direction and arranged on opposite sides of a drive unit 1.

[0032] The drive device comprises the drive unit 1 with two drive machines, 11, 12, in this case electric motors, and one in Fig. 2, a first portal gear 30, and a second portal gear 40. The central shaft unit 20 has a first central output element 21 and a second central output element 22. The first portal gear 30 has a first portal output element 33, in this case a cardan shaft flange. The second portal gear 40 has a second portal output element 43, in this case a cardan shaft flange. The respective portal output element 33, 43 is mechanically operatively connected to the respective central output element 21, 22 via the respective portal gear 30, 40.

[0033] The first portal output element 33 is mechanically operatively connected to the first differential gear 61 via a first transmission element 51, in this case a cardan shaft. The second portal output element 43 is mechanically operatively connected to the second differential gear 62 via a second transmission element 52, in this case a cardan shaft. Thus, the drive device is configured to drive the drive wheels via the drive unit 1.

[0034] The drive unit 1 has a drive housing to which a portal housing of the first portal gear 30 and a portal housing of the second portal gear 40 are fastened in the longitudinal direction on opposite sides via screw connections aligned in the longitudinal direction. The first portal output element 33 is arranged offset by an offset distance from a rotational axis of the first central output element 21 in an offset direction, in this case the direction of gravity downwards. The second portal output element 43 is arranged in the same offset direction and offset by the same offset distance from a rotational axis of the second central output element 22. The drive housing is arranged offset so far upwards in a direction of gravity that an underside of the drive housing is substantially aligned with the underside of the portal housing in the longitudinal direction.

[0035] As a result, the inclination of the first transmission element 51 and the second transmission element 52 with respect to the longitudinal direction is small. Furthermore, the downward extension of the drive unit 1 relative to the first portal output element 33 and the second portal output element 43 in the direction of gravity is small. This provides a large ground clearance for the drive device.

[0036] Fig. 2 schematically shows a detail of another embodiment of the drive device. The present embodiment has all the features of the previous embodiment. Each of the two drive motors 11, 12 has a rotor shaft, which are connected to one another in a rotationally fixed manner via the central shaft unit 20. The drive unit 1 has a manual transmission 15 with three shift stages, which is formed by a planetary gear set. The central shaft unit 20 extends longitudinally forward through the manual transmission 15 to the first portal transmission 30 and rearward to the second portal transmission 40. Alternatively, the single- / multi-speed transmission could also be located within the electric motors, virtually enclosed by the electric motors. The central shaft unit 20, in particular the first central output element 21 and the second central shaft output element 22, the drive motors 11, 12, and the manual transmission 15 are arranged coaxially with one another.

[0037] In the present embodiment, the first portal gear 30 and the second portal gear 40 are each designed as a spur gear. The first portal gear 30 has a first input gear 31 and a first output gear 32. The second portal gear 40 has a second input gear 41 and a second output gear 42. The respective input gear 31, 41 is connected in a rotationally fixed manner to the respective central output element 21, 22. The respective input gear 31, 41 is in engagement with the respective output gear 32, 42. The spur gears each have an output gear ratio of the input element 31, 41 to the output element 32, 42 of less than 1. The respective output gear 32, 42 is connected in a rotationally fixed manner to the respective portal output element 33, 43. The rotation axis of the respective portal output element 33, 43 is parallel to the rotation axis of the respective central output element 21, 22.

[0038] Fig. Figure 3 schematically shows a detail of another embodiment of the drive device. The present embodiment differs from the previous embodiment in the design of the first output gear 32 and the second output gear 42. In this case, the first output gear 32 and the second output gear 42 are each designed as a ring gear with internal teeth. As a result, the output gear ratio is lower than in the previous embodiment.

[0039] Fig. Figure 4 shows a schematic detail of another embodiment of the drive device. The present embodiment differs from that described with reference to Fig.2 by the design of the first portal gear 30 and the second portal gear 40. In this case, the first portal gear 30 and the second portal gear 40 are each designed as a bevel gear, in this case a beveloid gear. The orientation of the rotational axis of the first portal output element 33 and the second portal output element 43 is each slightly inclined downward. The rotational axis of the first portal output element 33 and the second portal output element 43 runs in the direction of the respective transmission element 51, 52. This supports a uniform rotational movement and reduces the propeller shaft deflection angle. Reference symbol 1 drive unit 11 First drive machine 12 Second drive machine 15 manual transmissions, single / multi-speed transmissions with differential or engagement 20 Central shaft unit 21 First central output element 22 Second central output element 30 First portal gear 31 First input gear 32 First output gear 33 First portal exit element 40 Second portal gear 41 First input gear 42 Second output gear 43 Second portal exit element 51 First transmission element 52 Second transmission element 61 First differential gear 62 Second differential gear 71 First drive axle 72 Second drive axle

Claims

[1] Drive device for a vehicle with all-wheel drive, comprising a drive unit (1) which has at least one drive motor (11, 12) and a central shaft unit (20), a first portal gear (30) and a second portal gear (40), wherein the central shaft unit (20) has a first central output element (21) and a second central output element (22), each for outputting a drive force from the drive unit (1) and is mechanically operatively connected to the drive motor (11, 12) for receiving a drive force, the first portal gear (30) is mechanically operatively connected to the drive unit (1) via the first central output element (21) for receiving a drive force and has a first portal output element (33) which is mechanically operatively connected to a first drive axle (71) via a first transmission element (51) for outputting a drive force, the second portal gear (40) is mechanically operatively connected to the drive unit (1) via the second central output element (22) for receiving a drive force and has a second portal output element (43) which is mechanically operatively connected to a second drive axle (72) for outputting a drive force via a second transmission element (52), and the first portal output element (33) is arranged in a direction offset from a rotational axis of the first central output element (21) and the second portal output element (43) is arranged in a direction offset from the rotational axis of the second central output element (22). [2] Drive device according to claim 1, characterized by that the first portal gear (30) and the second portal gear (40) are arranged on opposite sides in a longitudinal direction with respect to the drive unit (1). [3] Drive device according to one of the preceding claims, wherein at least one of the first portal gear (30) and the second portal gear (40) comprises a spur gear. [4] Drive device according to one of the preceding claims, characterized by that at least one of the first portal gear (30) and the second portal gear (40) has a bevel gear. [5] Drive device according to one of the preceding claims, characterized by that at least one of the first drive axle (71) and the second drive axle (72) is designed as a through-drive axle and is mechanically operatively connected to a further drive axle via a further transmission element in order to output a drive force. [6] Drive device according to one of the preceding claims, characterized by that at least one of the drive axles (71, 72) has a differential gear (61, 62) for driving two drive wheels. [7] Drive device according to one of the preceding claims, characterized by that the drive unit (1) has two drive machines (11, 12) which are mechanically operatively connected to the central shaft unit (20) for outputting a drive force. [8] Drive device according to one of the preceding claims, characterized by that the drive unit (1) has a differential gear which is mechanically operatively connected to the drive engine (11, 12) for receiving a drive force and is mechanically operatively connected to the first portal gear (30) and the second portal gear (40) for outputting a drive force. [9] Drive device according to one of the preceding claims, characterized bythat the drive unit (1) has a gearbox (15) which is mechanically operatively connected to the drive engine (11, 12) via the central shaft unit (20) for receiving a drive force and is mechanically operatively connected to the first portal gearbox (30) and the second portal gearbox (40) for outputting a drive force. [10] Vehicle with a drive device according to one of the preceding claims and four output elements which are arranged to drive the vehicle, two of the output elements being drivable by the first drive axle (71) and the other two output elements being drivable by the second drive axle (72).

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