Tandem axle for a motor vehicle, in particular for a commercial vehicle, motor vehicle and method for operating a motor vehicle of this type

Abstract

The invention relates to a tandem axle (10) for a motor vehicle, with a drivable first axle (12), which has a first differential gear (30) by means of which first vehicle wheels (14, 16) of the first axle (10) are can be driven. The first axle (12) comprises a first drive shaft (32), by means of which the first differential gear (30), and via the first differential gear (30) the first vehicle wheels (14, 16), can be driven. A drivable second axle (20) is provided which has a second differential gear (34), by means of which second vehicle wheels (22, 24) of the second axle (20) can be driven. The second axle (20) comprises a drive gearwheel (40), by means of which the second differential gear (34), and via the second differential gear (34) the second vehicle wheels (22, 24), can be driven. The second axle (20) comprises a second drive shaft (36), by means of which the drive gearwheel (40) can be driven. A clutch (70) is also provided.

Description

[0001] Tandem axle for a motor vehicle, in particular for a commercial vehicle, motor vehicle and method for operating such a motor vehicle

[0002] The invention relates to a tandem axle for a motor vehicle, in particular for a commercial vehicle, according to the preamble of patent claim 1. Furthermore, the invention relates to a motor vehicle, in particular a commercial vehicle, having such a tandem axle. The invention also relates to a method for operating a motor vehicle having such a tandem axle according to the preamble of patent claim 10.

[0003] DE 102006 045 007 A1 and WO 2008 / 019759 A1 disclose a tandem axle with two drivable axles, each axle comprising a differential with a drive gear driven via a shaft as the differential input, and two drive half-shafts driving the wheels of this axle via axle shaft gears. Furthermore, EP 3608 144 A1 discloses a method for controlling a drive axle system.

[0004] The object of the present invention is to provide a tandem axle for a motor vehicle, in particular for a commercial vehicle, a motor vehicle having such a tandem axle, and a method for operating a motor vehicle having such a tandem axle, so that particularly advantageous operation can be achieved. This object is achieved by a tandem axle having the features of patent claim 1, by a motor vehicle having the features of patent claim 9, and by a method having the features of patent claim 10.

[0005] Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims. A first aspect of the invention relates to a tandem axle for a motor vehicle, also simply referred to as a vehicle. This means that the motor vehicle, preferably designed as a commercial vehicle, in particular as a truck, has the tandem axle in its fully manufactured state. The tandem axle has a drivable first axle, which is also referred to as the first vehicle axle. The first axle has a first differential gear, which is also referred to as the first differential or first differential gear or first axle gear. First vehicle wheels of the first axle can be driven via the first differential gear. The first vehicle wheels are also referred to as first wheels.Furthermore, the first axle has a first drive shaft, by means of which the first differential gear and, via the first differential gear, the first vehicle wheels can be driven, whereby, for example, the motor vehicle as a whole can be driven. The feature that the first axle is a drivable first axle is to be understood as meaning that the first vehicle wheels can be driven by the first drive shaft via the first differential gear.

[0006] The tandem axle also has a drivable second axle provided in addition to the first axle, which is also referred to as the second vehicle axle. In particular, for example, the axles are arranged consecutively in the longitudinal direction of the motor vehicle and thus one behind the other, in particular such that the second axle adjoins the first axle towards the rear in the longitudinal direction of the motor vehicle. In particular, it is conceivable that the motor vehicle in its fully manufactured state has at least or exactly three axles, also referred to as vehicle axles, namely the first axle, the second axle and a third axle, which is also referred to as the third vehicle axle. In this case, it is particularly conceivable that the third axle is arranged in front of the first axle and in front of the second axle in the longitudinal direction of the motor vehicle, so that, for example, the third axle is a front axle.For example, since the first axle is arranged between the third axle and the second axle in the longitudinal direction of the motor vehicle, the first axle is a first rear axle, while, for example, since the second axle is arranged behind the first axle and the third axle in the longitudinal direction of the vehicle, the second axle is a second rear axle. In particular, the first axle is thus a front rear axle, and the second axle is a rear rear axle.

[0007] The second axle has a second differential gear provided in addition to the first differential gear, which is also referred to as a second differential, second differential gear or second axle gear. Second vehicle wheels of the second axle can be driven via the second differential, whereby the second vehicle wheels are also referred to as second vehicle wheels or second wheels. When reference is made to the vehicle wheels in the following, this means the first vehicle wheels and the second vehicle wheels, unless otherwise stated. When reference is made to the axles or the vehicle axles in the following, this means the first axle and the second axle, unless otherwise stated. The vehicle wheels of the axles are ground contact elements by means of which the motor vehicle can be or is supported downwards on a ground in the vertical direction of the motor vehicle.If the motor vehicle is driven along the ground while being supported downwards on the ground via the vehicle wheels in the vertical direction of the motor vehicle, the vehicle wheels roll, in particular directly, on the ground. The feature that the second axle is a drivable second axle means that the second vehicle wheels of the second axle are drivable, whereby, for example, the motor vehicle as a whole can be driven.

[0008] The second axle has a drive gear, which is also referred to as a pinion or drive pinion, for example. For example, the drive gear is a bevel gear, also referred to as a bevel gear. The drive gear can be used to drive the second differential gear and the second vehicle wheels via the second differential gear, whereby the motor vehicle as a whole can be driven, for example. This means that the drive gear can drive the second differential gear or the second vehicle wheels via the second differential gear. In addition, the second axle has a second drive shaft, which is provided in particular in addition to the first drive shaft and by means of which the drive gear can be driven and the second differential gear can be driven via the drive gear.Thus, for example, by driving the drive gear, the second differential gear can be driven, and by driving the second differential gear, the second vehicle wheels can be driven. The drive gear can be driven by means of the second drive shaft, in particular by driving the second drive shaft. Thus, the second drive shaft can drive the drive gear and, via the drive gear, drive the second differential gear. In particular, it is provided that the second drive shaft is connected to the drive gear, in particular permanently, in a torque-transmitting, in particular rotationally fixed manner.In the context of the present disclosure, the feature that two components such as the second drive shaft and the drive gear are connected to one another in a rotationally fixed manner is to be understood as meaning that the components connected to one another in a rotationally fixed manner are arranged coaxially to one another and, in particular when the components are driven, rotate together or simultaneously about a component rotation axis common to the components at the same angular velocity, in particular relative to a housing of the tandem axle.

[0009] The feature that two components, such as the second drive shaft and the drive gear, are connected or coupled to one another in a torque-transmitting manner, is to be understood as meaning that the components are coupled or connected to one another in such a way that torques can be transmitted between the components, wherein, if the components are connected or coupled to one another in a rotationally fixed manner, the components are also connected or coupled to one another in a torque-transmitting manner.

[0010] The feature that two components, such as the drive gear and the second drive shaft, are permanently connected or coupled to one another in a torque-transmitting manner is understood to mean that a switching element is not provided that can be switched between a coupling state that connects or couples the components to one another in a torque-transmitting manner and a decoupling state in which no torque can be transmitted between the components via the switching element. Rather, the components are always and thus permanently connected or coupled to one another in a torque-transmitting manner, i.e., such that torque can be transmitted between the components. Thus, for example, one of the components can be driven by the other component, or vice versa.

[0011] In particular, the feature that two components such as the second drive shaft and the drive gear are permanently connected or coupled to one another in a rotationally fixed manner is to be understood as meaning that a switching element is not provided which can be switched between a coupling state which connects or couples the components to one another in a rotationally fixed manner and a decoupling state in which the components are decoupled from one another and can be rotated relative to one another so that no torque can be transmitted between the components, but rather the components are always or always, and therefore permanently connected or coupled to one another in a rotationally fixed manner.

[0012] The tandem axle also has a clutch, which is designed, for example, as a multi-disk clutch. The clutch can be switched between a coupled state and a decoupling state, in particular by controlling the clutch. For example, the clutch can be controlled electrically or electronically, for example by means of an electronic computing device, in order to switch the clutch between the coupled state and the decoupling state, in particular in a targeted and thus active manner. In the coupled state, the second drive shaft is coupled to the drive shaft by means of the clutch, i.e. via the clutch, in a torque-transmitting manner, whereby the second drive shaft can be driven by the first drive shaft via the clutch.Thus, in the coupled state, the second vehicle wheels can be driven by the first drive shaft via the second differential gear and the second drive shaft, and, in particular simultaneously, the first vehicle wheels can be driven by the first drive shaft via the first differential gear, so that, for example, both the first vehicle wheels and the second vehicle wheels can be driven, and thus simultaneously.

[0013] In the decoupling state, the second drive shaft is decoupled from the first drive shaft, so that the first drive shaft cannot drive the second drive shaft via the clutch, thus preventing or preventing the first drive shaft from driving the second drive shaft via the clutch.

[0014] For example, in its fully manufactured state, the motor vehicle has at least one or precisely one drive motor, which can be configured, for example, as an internal combustion engine or an electric motor. For example, the first drive shaft can be driven by the drive motor, whereby the first vehicle wheels and, in particular in the coupled state, the second vehicle wheels can be driven by the drive motor.

[0015] For example, in the fully manufactured state of the motor vehicle having the tandem axle, the first vehicle wheels are arranged on opposite sides of the motor vehicle in the transverse direction of the motor vehicle. Furthermore, it is preferably provided that the second vehicle wheels are arranged on the opposite sides of the motor vehicle in the transverse direction of the motor vehicle.

[0016] In order to be able to realize particularly advantageous operation of the motor vehicle, it is provided according to the invention that the second axle has an axle housing in which the drive gear, which is rotatable relative to the axle housing, is at least partially, in particular at least predominantly and thus at least more than half or completely, received. Since the drive gear is rotatable relative to the axle housing and received, i.e. arranged, in the axle housing, the drive gear is rotatably received and thus arranged in the axle housing. In particular, a receiving space of the axle housing is delimited, in particular directly, by the axle housing, in particular by an inner circumferential surface of the axle housing, wherein the drive gear is at least partially, in particular at least predominantly and thus at least more than half or completely, rotatably arranged in the receiving space.Thus, the second drive shaft can also rotate relative to the axle housing. The axle housing is also referred to as a carrier or axle support. Furthermore, the second vehicle wheels, for example, can rotate relative to the axle housing, in particular about a respective wheel rotation axis.

[0017] According to the invention, the tandem axle also has a speed sensor by means of which a speed of the drive gear can be detected, i.e. measured. The speed sensor has a detection element fastened to the axle housing, which is particularly fastened to the axle housing in such a way that relative movements between the detection element and the axle housing are avoided, and thus prevented. Furthermore, the speed sensor has a sensor element that is connected, in particular permanently, in a rotationally fixed manner to the drive gear, the speed of which can be detected by means of the receiving element, whereby the speed of the drive gear can be detected by means of the speed sensor. The sensor element can be connected directly or indirectly to the drive gear in such a way that the sensor element is connected, in particular permanently, in a rotationally fixed manner to the drive gear.The sensor element can therefore rotate with the drive gear relative to the axle housing and also relative to the detection element. Since the sensor element is connected, in particular permanently, in a rotationally fixed manner to the drive gear, the speed of the sensor element corresponds to the speed of the drive gear and vice versa, so that by detecting the speed of the sensor element, the speed of the drive gear can be detected or is detected. Since the speed of the sensor element can be detected or is detected by means of the receiving element, the speed of the drive gear can be detected or is detected. With the invention, the speed of the drive gear can be detected particularly advantageously, in particular particularly robustly, so that, for example, particularly advantageous operation of the motor vehicle is subsequently possible depending on the detected speed of the drive gear.It has been found that, with the invention, the detection of the speed of the drive gear is not subject to excessive influences, in particular to the extent that, with the invention, the detection of the speed of the drive gear is not excessively impaired by fluids such as operating fluids. The invention is based in particular on the following findings and considerations: It is desirable to detect a measured variable, i.e. to be able to measure it, and based on the measured variable, to be able to determine whether the clutch is, in particular currently, in the coupled state or in the uncoupled state. If the clutch is in the coupled state, the clutch is closed. If the clutch is in the uncoupled state, the clutch is open.In principle, it would be conceivable to integrate a sensor into the clutch and, for example, to arrange it on a component such as a clutch pack of the clutch, in order to be able to use the sensor to record the aforementioned measured variable, which can be used to determine whether the clutch is, in particular currently, closed or open. However, in particular during operation of the tandem axle, the clutch is supplied with a fluid, in particular in the form of a liquid, which is, for example, one of the aforementioned operating fluids, whereby the fluid can be, for example, an oil. For example, the clutch is actuated and / or lubricated and / or cooled by means of the oil.By supplying the clutch with oil, the aforementioned sensor, which could be a switch, for example, may be exposed to an excessive amount of oil, which could undesirably impair the sensor's ability or capability to detect the measured variable. Alternatively or additionally, for example, by supplying the sensor with oil, the sensor's ability or capability to provide a signal characterizing the measured variable, such as an electrical transmission signal, may be undesirably impaired.The aforementioned electronic computing device, which may also be referred to or designed as a control unit, is fundamentally designed to receive the sensor signal provided by the sensor, whereby the electronic computing device can determine, on the basis of the received sensor signal characterizing the measured variable, whether the clutch is, in particular currently, closed or open. For example, the aforementioned sensor can be designed as a position sensor in order to be able to detect a position of the aforementioned component of the clutch, for example, so that the position is the aforementioned measured variable. In particular, such integration of the sensor into the clutch can lead to a leak, as a result of which the fluid can penetrate into a housing, in particular into a switch housing, of the sensor, which can lead to a failure of the sensor.

[0018] The aforementioned problems and disadvantages can now be avoided by the invention. According to the invention, the rotational speed of the drive gear is used as the aforementioned measured variable, which can be used to determine whether the clutch is, in particular, currently engaged or disengaged. Because the detection element is attached to the axle housing and the sensor element is rotationally fixedly connected to the drive gear, undesirable, excessive impairments in the detection of the rotational speed of the drive gear can be avoided.If, for example, the speed sensor detects that the speed of the drive gear is different from zero, in particular is greater than zero, so that the drive gear rotates relative to the axle housing, it can be determined that the clutch is closed, because then the drive gear is driven by the second drive shaft, and the second drive shaft is driven by the first drive shaft via the clutch, which is only possible in the coupled state with respect to the coupled state and the uncoupled state.However, if it is detected, for example, by means of the speed sensor that the, in particular current, speed of the drive gear is zero, and therefore that the drive gear is not rotating, in particular while the first drive shaft is rotating, in particular while the first drive shaft is driven by the drive motor and is therefore rotating, it can be inferred or determined that the clutch is currently open, because then the drive gear is not driven by the second drive shaft and the second drive shaft is not driven via the clutch of the first drive shaft, which, in particular with regard to the coupling state and the decoupling state, is only possible in the decoupling state and can therefore be the case.

[0019] The speed sensor is preferably designed to provide a signal, in particular an electrical signal, which characterizes the speed of the drive gear detected by the sensor. The aforementioned electronic computing device can receive the signal and subsequently determine, based on the detected speed of the drive gear characterized by the signal, whether the clutch is, in particular currently, open or closed. As a result, it is possible, for example, for the motor vehicle, in particular the clutch, to be operated depending on the signal, i.e., depending on the detected speed of the drive gear, in particular by means of the electronic computing device.

[0020] In particular, an operating strategy provided for operating the motor vehicle, in particular for operating the tandem axle and especially for operating the clutch, can be implemented depending on the detected speed of the drive gear. In this case, it is particularly conceivable for the clutch, for example, to be operated depending on the detected speed of the drive gear, in particular such that the clutch is switched between the coupling state and the decoupling state depending on the detected speed of the drive gear.

[0021] In order to be able to detect the rotational speed of the drive gear particularly advantageously and subsequently to realize a particularly advantageous operation of the motor vehicle, in particular one which depends on the detected rotational speed of the drive gear, it is provided in one embodiment of the invention that the sensor element is formed separately from the drive gear and is connected, in particular permanently, in a rotationally fixed manner to the drive gear.

[0022] A further embodiment is characterized in that the drive gear has a toothing, which is also referred to as the first toothing, and a shaft stub formed integrally with the toothing, on which the sensor element is provided, in particular formed or arranged. When reference is made above and below to the toothing, this refers, unless otherwise stated, to the first toothing of the drive gear. The feature that the toothing and the shaft stub are formed integrally with one another is to be understood as meaning that the shaft stub and the toothing are formed from a single piece.In other words, the toothing and the shaft stub are preferably formed by a one-piece, thus integrally formed body, which, due to the fact that the body is formed in one piece, thus formed from a single piece, is formed as a one-piece, thus formed from a single piece, and thus integrally manufactured monoblock. This means that preferably the toothing and the shaft stub are not formed as separate and joined parts, but rather the toothing and the shaft stub are preferably formed from a single piece, thus integrally formed with one another, and thus formed as a monoblock or formed by a monoblock.For example, the toothing engages with a second toothing of a second gear of the differential gear, so that the second gear and thus the second differential gear can be driven by the drive gear. For example, the second gear is a ring gear. For example, the second gear is connected, in particular permanently, in a rotationally fixed manner to a differential housing of the second differential gear, embodied, for example, as a differential carrier or also referred to as a differential carrier.

[0023] Since the sensor element is preferably provided on the shaft stub, and since the toothing is formed integrally with the shaft stub, so that the toothing and the shaft stub rotate or can rotate at the same speed of the drive gear relative to the axle housing, the speed of the drive gear can be detected particularly advantageously and robustly by means of the receiving element and by means of the sensor element, so that advantageous operation of the motor vehicle can be ensured, in particular on the basis of the detected speed of the drive gear.

[0024] Most preferably, the sensor element is formed separately from the shaft end and thus separately from the gearing, and is connected, in particular permanently and non-rotatably, to the shaft end. This allows the rotational speed of the drive gear to be detected particularly robustly. This means that excessive influences that could affect the detection of the rotational speed of the drive gear can be avoided, or the rotational speed of the drive gear can be advantageously detected despite such influences.

[0025] A further embodiment is characterized in that the tandem axle has a spacer element formed separately from the drive gear, which is connected, in particular permanently, to the drive gear in a rotationally fixed manner. For example, the spacer element is a ring, i.e., annular, so that, for example, the spacer element rotates completely, i.e., completely closed, in the circumferential direction of the drive gear, whose axial direction runs perpendicular to the radial direction of the drive gear. The circumferential direction of the drive gear extends around the axial direction of the drive gear. In particular, the drive gear is rotatable about a gear rotation axis relative to the axle housing, wherein the axial direction of the drive gear coincides with the gear rotation axis.By means of the spacer element, two bearings, by means of which the drive gear is rotatably mounted on the axle housing, are held at a distance from each other in the axial direction of the drive gear. For example, the bearings are designed as rolling bearings, in particular as tapered bearings, in order to realize a low-friction mounting of the drive gear.

[0026] It is further provided that the sensor element, which is formed separately from the drive gear and separately from the spacer element, is connected, in particular permanently, rotationally to the spacer element and, in particular exclusively, via the spacer element, in particular permanently, rotationally to the drive gear. Thus, the spacer element, the sensor element, and the drive gear rotate at the same or the same speed, in particular about the gear rotation axis, relative to the axle housing, so that the speed of the drive gear can be detected particularly robustly and thus reliably and precisely.

[0027] It has proven particularly advantageous if the sensor element at least partially, in particular at least predominantly, and thus at least more than half or even completely, surrounds the spacer element in the circumferential direction of the drive gear, extending around the axial direction of the drive gear. This allows the rotational speed of the drive gear to be detected, i.e., measured, robustly and precisely.

[0028] In a further, particularly advantageous embodiment of the invention, it is provided that the spacer element, which is formed separately from the drive gear and thus separately from the stub shaft and separately from the toothing, is connected, in particular permanently, in a rotationally fixed manner to the stub shaft and completely surrounds the stub shaft in the circumferential direction of the stub shaft and thus of the drive gear, i.e. completely circumferentially. In particular, it is provided that the toothing of the drive gear adjoins the stub shaft in the axial direction of the drive gear, wherein, for example, the toothing of the drive gear has a larger diameter than the stub shaft, in particular such that the largest diameter, in particular outer diameter, of the toothing is larger than the largest diameter, in particular outer diameter of the stub shaft.Thus, the sensor element is provided on the shaft stub in such a way that the spacer element, which is formed separately from the drive gear and thus separately from the shaft stub and separate from the gearing, is connected, in particular permanently, in a rotationally fixed manner to the shaft stub. The sensor element is connected, in particular permanently, in a rotationally fixed manner to the spacer element via the latter to the shaft stub. This allows the rotational speed of the drive gear to be measured robustly and precisely, whereby the motor vehicle can be operated particularly advantageously based on the measured, and thus detected, rotational speed of the drive gear.

[0029] Finally, it has proven particularly advantageous if the speed sensor has a connection device by means of which the speed sensor can be or is electrically connected to at least one line, in particular one formed separately from the speed sensor. The connection device is arranged outside the axle housing, in particular outside the receiving space, so that the connection device is arranged, for example, in an area surrounding the axle housing. In particular, the speed sensor can provide the aforementioned, preferably electrical, signal via the connection device, wherein the speed sensor can transmit the signal to the line via the connection device.The line can thus receive the signal via the connection device, and the line can conduct the signal, in particular to the electronic computing device, which can thus receive the signal conducted via the line and provided or that can be provided by the line. By arranging the connection direction of the speed sensor outside the axle housing, it can be avoided that the connection device is excessively exposed to an operating fluid such as the aforementioned oil, so that the signal can be transmitted reliably and robustly. Consequently, advantageous operation of the motor vehicle can be achieved based on the signal that characterizes the detected speed of the drive gear.Because the connecting element (also known as a connecting device, connecting assembly, or speed sensor connecting element) is located outside the axle housing (also known as the carrier), the connecting element is protected from excessive oil leakage. Failures due to side-load vibrations can also be avoided, allowing the drive gear speed to be measured robustly and precisely.

[0030] A second aspect of the invention relates to a motor vehicle, also referred to simply as a vehicle, which has a tandem axle according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be regarded as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.

[0031] A third aspect of the invention relates to a method for operating a motor vehicle having a tandem axle, in particular according to the first aspect of the invention, which is also simply referred to as a vehicle. In the method, the tandem axle has a drivable first axle which has a first differential gear, via which first vehicle wheels of the first axle can be driven. In the method, the first axle has a first drive shaft, by means of which the first differential gear and, via the first differential gear, the first vehicle wheels can be driven. In the method, the tandem axle has a drivable second axle which has a second differential gear, via which second vehicle wheels of the second axle can be driven. The second axle has a drive gear, by means of which the second differential gear and, via the second differential gear, the first vehicle wheels can be driven.Furthermore, the second axle has a second drive shaft, by means of which the drive gear can be driven. In the method, the tandem axle has a clutch that can be switched, in particular is switched, between a coupled state and a decoupling state. In the coupled state, the second drive shaft is coupled to the first drive shaft by means of the clutch, i.e., via the clutch, in a torque-transmitting manner, whereby the second drive shaft can be driven, in particular is driven, by the first drive shaft via the clutch. In the decoupling state, the second drive shaft is decoupled from the first drive shaft.

[0032] In order to be able to operate the motor vehicle particularly advantageously, the third aspect of the invention provides that the second axle has an axle housing in which the drive gear, which is rotatable relative to the axle housing, is received, i.e. arranged. A speed sensor is also provided, by means of which a speed of the drive gear is detected. For this purpose, the speed sensor has a detection element fastened to the axle housing and a sensor element which is connected, in particular permanently, in a rotationally fixed manner to the drive gear and which is connected directly or indirectly to the drive gear in such a way that the sensor element is rotationally fixedly connected to the drive gear. A speed of the sensor element is detected by means of the receiving element, whereby the speed of the drive gear is detected by means of the speed sensor, in particular in that the speed of the sensor element includes the speed of the drive gear.This is particularly the case because the sensor element is connected, in particular permanently, to the drive gear in a rotationally fixed manner. Furthermore, the method according to the third aspect of the invention provides that the motor vehicle is operated as a function of the speed of the drive gear detected, i.e., measured, by means of the speed sensor. For example, it is provided that the clutch is switched between the coupled state and the uncoupled state as a function of the speed of the drive gear detected by the speed sensor. Advantages and advantageous embodiments of the first aspect and the second aspect of the invention are to be viewed as advantages and advantageous embodiments of the third aspect of the invention, and vice versa.

[0033] In particular, it is conceivable for the tandem axle to be operated depending on the detected speed of the drive gear. The clutch is preferably designed as a multi-disk clutch, which preferably has a plurality of multi-disk discs arranged successively, particularly in the axial direction of the clutch, in particular as the aforementioned discs.

[0034] It is conceivable, particularly in the case of the operating strategy, that the clutch is switched between the coupling state and the decoupling state depending on a particular current speed of the motor vehicle, also referred to as the driving speed. Alternatively or additionally, for example, in the case of the operating strategy, the clutch is switched between the coupling state and the decoupling state depending on a slip of at least one of the vehicle wheels. In particular, it is conceivable, particularly in the case of the operating strategy, that the second axle is optionally coupled to the first axle or decoupled from the first axle depending on a particular current driving situation. To couple the second axle to the first axle, i.e. to couple the second axle to the first axle, the clutch is closed, and the coupling state of the clutch is thus set.To decouple the second axle from the first axle, the clutch is opened, thus setting the decoupling state. Thus, it is conceivable that the clutch is switched between the coupled state and the uncoupled state depending on the current driving situation of the vehicle, particularly with the aforementioned operating strategy.

[0035] For example, the sensor element is annular and thus designed as a measuring ring which extends, for example, in the circumferential direction of the drive gear running around the axial direction of the drive gear, in particular in a closed and thus completely manner. For example, the sensor element is connected to the drive gear in a rotationally fixed manner by means of a press fit. It is particularly conceivable for the sensor element to be pressed onto the drive gear, in particular onto the stub shaft. Very particularly, it is conceivable for the sensor element to be connected to the spacer element in a rotationally fixed manner by means of a press fit, so that, for example, the sensor element is pressed onto the spacer element. It is conceivable for the spacer element to be connected to the drive gear, in particular to the stub shaft, in a rotationally fixed manner by means of a press fit.For example, the spacer element is pressed onto the drive gear, in particular onto the shaft stub. The sensor element provides the receiving element with information that the receiving element can use to detect the speed of the sensor element and thus the speed of the drive gear. For this purpose, the sensor element has recesses, which can be designed, for example, as blind holes or through openings. Furthermore, in addition to the recesses, the sensor element has subregions, which are designed, for example, as projections, also referred to as bulges.The aforementioned partial regions of the sensor element are raised outwards relative to the recesses, in particular in the radial direction of the drive gear and thus of the sensor element, so that, for example, the recesses are set back inwards relative to the partial regions in the radial direction of the drive gear. In particular, it is provided that the recesses and the partial regions of the sensor element are arranged alternately one after the other in the circumferential direction of the drive gear and thus of the sensor element, extending around the axial direction of the drive gear. The receiving element is designed to detect the rotational speed of the sensor element and thus the rotational speed of the drive gear based on the partial regions and the recesses of the sensor element, in particular when the drive gear and thus the sensor element rotates.The recesses and the sub-areas thus form a kind of knife toothing, which allows the speed of the sensor element and thus the speed of the drive gear to be detected by the receiver element. This ensures robust and precise detection, i.e., measurement of the speed of the drive gear.

[0036] The axle housing, for example, is designed as a cast component and thus manufactured by casting. However, the axle housing has, for example, a fastening element by means of which the receiving element is attached to the axle housing. In particular, it is conceivable that the fastening element is manufactured by casting, which is also the method used to manufacture the axle housing. The sensor element is formed, for example, from sheet metal.

[0037] The invention enables the current state of the clutch to be detected robustly and precisely. This means that the invention enables the robust and precise determination of whether the clutch, especially currently, is in the coupled or uncoupled state. In particular, the invention enables the detection of the following errors or error causes:

[0038] - specifying the wrong coupling for the application

[0039] - an algorithm causes the clutch to go through more cycles than intended

[0040] - Errors in laser welding

[0041] - Failure of a vehicle air valve

[0042] - input torque too high

[0043] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawings. The features and combinations of features mentioned above in the description, as well as the features and combinations of features mentioned below in the description of the figures and / or shown alone in the figures, can be used not only in the respective specified combinations, but also in other combinations or on their own, without departing from the scope of the invention.

[0044] The drawing shows:

[0045] Fig. 1 is a schematic representation of a tandem axle for a motor vehicle;

[0046] Fig. 2 is a schematic perspective view of an axle housing of the

[0047] tandem axle;

[0048] Fig. 3 is a further schematic perspective view of the axle housing;

[0049] Fig. 4 shows a further schematic perspective view of the axle housing;

[0050] Fig. 5 shows a further schematic perspective view of the axle housing;

[0051] Fig. 6 is a schematic perspective view of a receiving element of the tandem axle; Fig. 7 is a partial schematic and perspective sectional view of the axle housing and a drive gear of the tandem axle;

[0052] Fig. 8 is a schematic perspective view of a sensor element of the tandem axle designed as a measuring ring;

[0053] Fig. 9 is a schematic perspective view of a structural unit of the tandem axle, since the structural unit includes the sensor element; and

[0054] Fig. 10 is a block diagram illustrating a method for operating the motor vehicle.

[0055] In the figures, identical or functionally identical elements are provided with the same reference numerals.

[0056] Fig. 1 shows a schematic representation of a tandem axle 10 for a motor vehicle, also simply referred to as a vehicle, and preferably designed as a commercial vehicle, in particular a truck. The tandem axle 10 has a drivable first axle 12, which has first vehicle wheels 14 and 16. The vehicle wheels 14 and 16 are arranged on opposite sides of the motor vehicle in the transverse direction of the motor vehicle, with the transverse direction of the vehicle being illustrated by a double arrow 18. The tandem axle 10 also has a second axle 20, which has second vehicle wheels 22 and 24.The vehicle wheels 22 and 24 are arranged on sides opposite one another in the transverse direction of the vehicle, so that, for example, the vehicle wheels 14 and 22 are arranged on a first of the sides of the motor vehicle and the vehicle wheels 16 and 24 are arranged on a second of the sides of the motor vehicle, wherein the first side and the second side are opposite one another in the transverse direction of the vehicle. It can be seen that the vehicle wheels 14, 16, 22 and 24 are twin wheels and thus each have a twin tire. The vehicle wheels 14, 16, 22 and 24 are ground contact elements by means of which the motor vehicle can be or is supported downwards on a ground in the vertical direction of the vehicle. The vertical direction of the motor vehicle runs perpendicular to the image plane of Fig. 1 and thus perpendicular to the transverse direction of the vehicle and is illustrated by a double arrow 26.It can be seen that the axles 12 and 20 are arranged consecutively in the longitudinal direction of the motor vehicle and thus one behind the other, such that the axle 20 adjoins the axle 12 towards the rear in the longitudinal direction of the vehicle. The vehicle's longitudinal direction runs perpendicular to the vehicle's transverse direction and perpendicular to the vehicle's vertical direction and is illustrated by a double arrow 28. The respective axle 12, 20 is also referred to as the respective vehicle axle.

[0057] The feature that the axle 12 is a drivable axle means that the vehicle wheels 14 and 16, and not just the motor vehicle as a whole, can be driven. For this purpose, the first axle 12 has a first differential gear 30, via which the vehicle wheels 14 and 16 of the axle 12 can be driven. In addition, the first axle 12 has a first drive shaft 32, which can be driven, for example, by a drive engine of the motor vehicle (not shown in the figures). By driving the first drive shaft 32, the differential gear 30 can be driven by means of the first drive shaft 32, and the vehicle wheels 14 and 16 can be driven by driving the first differential gear 30. Thus, the first differential gear 30 can be driven by means of the first drive shaft 32, and the vehicle wheels 14 and 16 can be driven via the first differential gear 30.

[0058] The feature that the second axle 20 is drivable, and is therefore a drivable axle, means that the vehicle wheels 22 and 24 of the axle 20, and thus the motor vehicle as a whole, can be driven. For this purpose, the second axle 20 has a second differential gear 34, which is provided in particular in addition to the first differential gear 30. In addition, the second axle 20 has a second drive shaft 36, by means of which the second differential gear 34 can be driven by driving the second drive shaft 36. By driving the differential gear 34, the vehicle wheels 22 and 24 can be driven. Thus, the second differential gear 34 can be driven by means of the second drive shaft 36, and the second vehicles 22 and 24 can be driven via the second differential gear 34.

[0059] The first axle 12 has a first drive gear 38, which is designed, for example, as a first bevel gear. The first drive gear 38 can be driven by means of the first drive shaft 32, and for example by the drive gear 38 being connected, in particular permanently, in a rotationally fixed manner to the drive shaft 32. The second axle 20 has a second drive gear 40 provided in addition to the drive gear 38. The first differential gear 30 and, via the first differential gear 30, the first vehicle wheels 14 and 16 can be driven by means of the drive gear 38, so that by driving the drive shaft 32, the drive gear 38 can be driven, by driving the drive gear 38, the differential gear 30 can be driven, and by driving the differential gear 30, the vehicle wheels 14 and 16 can be driven.The second vehicle wheels 22 and 24 can be driven by means of the second drive gear 40 as a second differential gear 34, and via the second differential gear 34. Thus, by driving the drive shaft 36, the drive gear 40 can be driven, by driving the drive gear 40, the differential gear 34 can be driven, and by driving the differential gear 34, the vehicle wheels 22 and 24 can be driven. Thus, the vehicle wheels 22 and 24 can be driven by the drive gear 40 via the differential gear 34, and vehicle wheels 14 and 16 can be driven by the first drive gear 38 via the differential gear 30. For example, the first drive gear 38 is designed as a bevel gear. For example, the second drive gear 40 is designed as a bevel gear.

[0060] From Fig. 1, it can be seen that the respective differential gear 30, 34 has a respective input gear 42, 44. The respective input gear 42, 44 is a respective gear. For example, the respective input gear 42, 44 is a respective ring gear. The drive gear 38 meshes with the input gear 42, and the drive gear 40 meshes with the input gear 44. For this purpose, for example, the drive gear 38 has a first toothing, and the input gear 42 has a second toothing, with which the first toothing engages or meshes, whereby the drive gear 38 engages or meshes with the input gear 42. The drive gear 40 has, for example, a third toothing, and the input gear 44 has, for example, a fourth toothing, with which, for example, the third toothing engages or meshes, whereby the drive gear 40 engages or meshes with the input gear 44.For example, the respective differential gear 30, 34 has a respective differential housing 46, 48, which is designed, for example, as a respective differential carrier. In addition, the respective differential gear 30, 34 has differential gears 50 and 52, respectively, and the respective differential gear 30, 34 has output gears 54 and 56, respectively. The differential gears 50 and the output gears 54 are gears, with the differential gears 50 meshing with the output gears 54. The differential gears 52, 56 are gears, with the differential gears 52 meshing with the output gears 56. The respective differential gear 50, 52 is mounted on the respective differential housing 46, 48, at least indirectly, so as to be rotatable about a first axis of rotation relative to the respective differential housing 46, 48.The respective output gear 54, 56 is rotatable about a second axis of rotation relative to the respective differential housing 46, 48, wherein the respective second axis of rotation runs perpendicular to the respective first axis of rotation. By driving the respective differential housing 46, 48, which is drivable by driving the respective differential gear 30, 34, the differential gears 50, 52 can be driven, wherein by driving the differential gears 50, 52 the output gears 54, 56 can be driven. By driving the output gears 54, the vehicle wheels 14 and 16 can be driven, and by driving the output gears 56, the vehicle wheels 22, 24 can be driven. In the embodiment shown in Fig. 1, the respective differential gear 30, 34 is designed as a respective bevel gear differential.

[0061] The first axle 12 has first sideshafts 58 and 60, wherein the sideshaft 58 is drivable by a first of the output gears 54 and the sideshaft 60 is drivable by a second of the output gears 54. For example, the sideshaft 58 is permanently coupled to the first output gear 54 in a torque-transmitting manner, and the sideshaft 60 is permanently coupled to the second output gear 54 in a torque-transmitting manner. The vehicle wheel 14 can be driven by means of the sideshaft 58 by driving the sideshaft 58, and the vehicle wheel 16 can be driven by means of the sideshaft 60 by driving the sideshaft. The sideshaft 58 can be driven by means of the first output gear 54 by driving the first output gear 54, and the sideshaft 60 can be driven by means of the second output gear 54.

[0062] The second axle 20 has a third side shaft 62 assigned to the vehicle wheel 22, which is assigned to a first of the output gears 56. The second axle 20 also has a fourth side shaft 64 assigned to the vehicle wheel 24, which is assigned to a second of the output gears 56. The vehicle wheel 22 can be driven by means of the side shaft 62 by driving the side shaft 62, and the vehicle wheel 24 can be driven by means of the side shaft 64 by driving the side shaft 64. The side shaft 62 can be driven by means of the first output gear 56 by driving the first output gear 56, so that the vehicle wheel 22 can be driven via the side shaft 62 by means of the drive gear 56.By driving the second output gear 56, the sideshaft 64 can be driven, so that the vehicle wheel 24 can be driven via the sideshaft 64 by means of the second output gear 56. The axle 20 has a first clutch device 66 associated with the first output gear 56 and the sideshaft 62, and a second clutch device 68 associated with the sideshaft 64 and the second output gear 56. The respective clutch device 66, 68 can be switched between a respective connected state and a respective released state, in particular by electrically or electronically controlling the respective clutch device 66, 68.In the respective connection state of the respective coupling device 66, 68, the respective side shaft 62, 64 assigned to the respective coupling device 66, 68 is coupled via the respective associated coupling device 66, 68 in a torque-transmitting manner to the respective associated and thus associated output gear 56, so that in the connection states of the coupling device 66 and 68, the output gears 56 can drive the side shafts 62 and 64 and thus the vehicle wheels 22 and 24 via the coupling devices 66 and 68. However, in the respective release state of the respective clutch device 66, 68, the respective assigned and thus associated side shaft 62, 64 is decoupled from the respective assigned and thus associated output gear 56, so that in the release states of the clutch devices 66 and 68, the output gears 56 cannot drive the side shafts 62 and 64 and thus the vehicle wheels 22 and 24.

[0063] The tandem axle 10 also has a clutch 70, which is provided in particular in addition to the clutch devices 66 and 68 and is preferably designed as a multi-disk clutch. The clutch 70 is very preferably designed as a multi-disk clutch, which comprises a plurality of multi-disk disks arranged consecutively in the axial direction of the clutch 70, as the aforementioned disks. The clutch 70 can be switched between a coupled state and a decoupling state. In the coupled state, the second drive shaft 36 is coupled to the first drive shaft 32 by means of the clutch 70 in a torque-transmitting manner, whereby the second drive shaft 36 can be driven by the first drive shaft 32 via the clutch 70. In the decoupling state, the second drive shaft 36 is decoupled from the first drive shaft 32, whereby the drive shaft 36 cannot be driven by the drive shaft 32 via the clutch 70.

[0064] In the embodiment shown in Fig. 1, a third drive gear 72 is connected, in particular permanently, in a rotationally fixed manner to the drive shaft 32. A fourth drive gear 74 is connected, in particular permanently, in a rotationally fixed manner to an input element 76 of the clutch 70. For example, the drive gears 72 and 74 are designed as spur gears. The drive gears 72 and 74 are in engagement with one another, i.e., they mesh with one another. For example, the input element 76 is or comprises a first disk carrier. By means of the disk discs, the input element 76 can be connected in a torque-transmitting manner, in particular in a rotationally fixed manner, to an output element 78 of the clutch 70, wherein, for example, the output element 78 comprises a second disk carrier or is a second disk carrier.The drive shaft 36 can be driven by an output element 78 of the clutch 70, in particular in such a way or by the fact that the drive shaft 36 is connected, in particular permanently, in a torque-transmitting, in particular rotationally fixed, manner to the output element 78. In the coupled state of the clutch 70, the output element 78 can thus be driven by the drive shaft 32 via the input element 76 and the drive gears 72 and 74, whereby the drive shaft 32 can drive the drive shaft 36 via the clutch 70. In the uncoupled state, the output element 78 is decoupled from the input element 76, so that the input element 76 and thus the drive shaft 32 cannot drive the output element 78 and thus cannot drive the drive shaft 36.

[0065] For example, the respective coupling device 66, 68 is designed as a respective claw coupling, so that by means of the respective coupling device 66, 68 the respective side shaft 62, 64 can be positively connected to the respective associated output gear 56.

[0066] It can be seen particularly well in conjunction with Fig. 2 that the second axle 20 has an axle housing 80, also referred to as a carrier or axle carrier, wherein the respective vehicle wheel 22, 24 is rotatable relative to the axle housing 80, in particular about a respective wheel axis of rotation. The axle housing 80 is also particularly clearly visible in Fig. 3 and Fig. 4. The axle housing 80 is also particularly clearly visible in Fig. 5 and 7. It can be seen particularly well in Fig. 7 that a receiving space 84 is delimited, in particular directly, by the axle housing 80, in particular by an inner circumferential surface 82 of the axle housing 80. The second drive gear 40 is received in the receiving space 84 and thus in the axle housing 80.The drive gear 40 is rotatable about a gear rotation axis 86 relative to the axle housing 80, wherein the gear axis 86 runs in the axial direction of the drive gear 40, the radial direction of which runs perpendicular to the axial direction of the drive gear 40. In this case, the axial direction of the drive gear 40 coincides with the gear rotation axis 86. Furthermore, it is particularly clear from Figs. 7 to 9 that the tandem axle 10 has a speed sensor 88, by means of which a speed of the drive gear 40 can be detected. If the drive gear 40 is driven by the drive shaft 36, the drive gear 40 rotates at the aforementioned speed of the drive gear 40 about the gear rotation axis 86 relative to the axle housing 80, which is, for example, the aforementioned housing of the tandem axle 10.7 and 5 show a coupling element 90 which is formed separately from the drive gear 40 and is, in particular, permanently and rotationally connected to the drive gear 40, by means of which, for example, the drive gear 40 is, in particular permanently, torque-transmitting, in particular rotationally coupled, to the drive shaft 36.

[0067] The speed sensor 88 has a receiving element 92 which is formed separately from the axle housing 80 and fastened to the axle housing 80, as well as a sensor element 94 which is particularly clearly visible in Fig. 8 and which, in the exemplary embodiment shown in the figures, is annular and thus designed as a ring. The ring is also referred to as a measuring ring. The sensor element 94 is, in particular permanently, rotationally connected to the drive gear 40, wherein a rotational speed of the sensor element 94 can be detected by means of the receiving element 92. By detecting the rotational speed of the sensor element 94, the rotational speed of the drive gear 40 can be detected. Because the sensor element 94 is rotationally connected to the drive gear 40, the rotational speed of the sensor element 94 corresponds to the rotational speed of the drive gear 40. It can be seen from Fig. 8 that the sensor element 94 has recesses 96 which, in the present case, are designed, for example, as through-openings.Between each two recesses 96 that directly follow one another and are thus adjacent to one another in the circumferential direction of the drive gear 40 and thus of the sensor element 94, running around the axial direction of the drive gear 40, a respective further partial region 98 of the sensor element 94 is arranged, in particular precisely, wherein the recesses 96 and the partial regions 98 are arranged alternately one after the other in the circumferential direction of the drive gear 40 and thus of the sensor element 94. The circumferential direction of the drive gear 40 and thus of the sensor element 94 is shown in Fig.7 illustrated by a double arrow 100 If the drive gear 40 and thus the sensor element 94 rotate about the gear axis of rotation 86 relative to the axle housing 80, the alternating recesses 96 and partial areas 98 cause, for example, changes in a measurement signal provided, for example, by the speed sensor 88, wherein the respective speed, thus the speed of the drive gear 40, can be detected as a function of these changes.

[0068] The aforementioned second toothing of the drive gear 40 is partially visible in Fig. 7 and designated 102. It can be seen that the drive gear 40 has the toothing 102 and a stub shaft 104, wherein the toothing 102 and the stub shaft 104 are formed integrally with one another, thus being formed from a single piece. The drive gear 40 is rotatably mounted on the axle housing 80 about the gear rotation axis 86 relative to the axle housing 80 via the stub shaft 104, in this case such that the stub shaft 104 and thus the drive gear 40 are rotatably mounted on the axle housing 80 via two bearings 106 and 108. The bearings 106 and 108 are designed as rolling bearings, in particular as tapered bearings. The bearings 106 and 108 are arranged successively in the axial direction of the drive gear 40 and in particular are spaced apart from one another.In this case, a spacer element 110 is provided, which is formed separately from the drive gear 40 and thus separately from the shaft stub 104 and separately from the toothing 102. This spacer element is designed as a ring and thus completely surrounds at least a length of the shaft stub 104 in the circumferential direction of the drive gear 40. The spacer element 110 is arranged in the axial direction of the drive gear 40 between the bearings 106 and 108, in particular between the inner bearing rings of the bearings 106 and 108, wherein the bearings 106 and 108, in particular their inner bearing rings, are held at a distance from one another in the axial direction of the drive gear 40 by means of the spacer element 108.The spacer element 110, which is formed separately from the drive gear 40 and thus separately from the shaft stub 104 and separately from the toothing 102, is connected, in particular permanently, in a rotationally fixed manner to the shaft stub 104 and thus to the drive gear 40, for example by the spacer element 110 being pressed onto the shaft stub 104 and thus onto the drive gear 40.

[0069] Fig. 9 shows a structural unit 112 comprising the sensor element 94 and the spacer element 110. The sensor element 94 is formed separately from the drive gear 40 and, in the present case, is connected, in particular permanently, in a rotationally fixed manner to the drive gear 40 in such a way that the sensor element 94 is formed separately from the spacer element 110, is arranged on the spacer element 110, and is, in particular permanently, in a rotationally fixed manner to the spacer element 110. Since, in the exemplary embodiment shown in the figures, the sensor element 94 is formed as a ring, the sensor element 94 completely surrounds at least a respective length region of the spacer element 110 and the shaft stub 104 in the circumferential direction of the drive gear 40.For example, the sensor element 94, which is formed separately from the drive gear 40 and separately from the spacer element 110, is connected to the spacer element 110 in a rotationally fixed manner by means of a press fit, in particular permanently, so that the sensor element 94 is connected to the drive gear 40 via the spacer element 110, in particular permanently, in a rotationally fixed manner. The axial direction of the drive gear 40 coincides with the gear rotation axis 86 and is illustrated by an arrow 114.

[0070] It can be seen particularly well from Fig. 6 that the receiving element 92 and thus the speed sensor 88 has a connection device 116, by means of which the speed sensor 88 can be or is electrically connected to a line (not shown in the figures) and formed separately from the speed sensor 88. The receiving element 92 can, for example, provide an electrical signal which characterizes the speed of the drive gear 40 detected by the speed sensor 88. Via the connection device 116, the preferably electrical signal can be transmitted electrically from the receiving element 92 to the line, which can, for example, carry the signal to an electronic computing device, also referred to as a control unit, of the tandem axle 10. The line can provide the signal, wherein the electronic computing device can receive the signal provided by the line.As a result, for example, the electronic computing device can operate the motor vehicle, in particular the tandem axle 10, depending on the received signal, in particular depending on the speed of the drive gear 40 detected by means of the speed sensor 88.

[0071] It can be seen particularly clearly from Fig. 7 that the connecting device 116 is arranged outside the receiving space 84 and thus outside the axle housing 80 and thus in an environment 118 of the axle housing 80. In particular, the connecting device 116 is arranged on an outer side 122 of the axle housing 80 facing the environment 118 and facing away from the receiving space 84 and the inner circumferential surface 82.

[0072] Fig. 10 shows a block diagram illustrating a method for operating the tandem axle 10. In particular, for example, the motor vehicle, in particular the tandem axle 10, is operated according to an operating strategy. In Fig. 10, blocks B1, B2, B3 and B4 illustrate different operating modes of the tandem axle 10. Furthermore, arrows in Fig. 10 illustrate that it is possible to switch between the different operating modes B1, B2, B3 and B4 of the tandem axle 10, simply referred to as modes, wherein, for example, the electronic computing device switches between the modes depending on the detected rotational speed of the drive gear 40. Operating mode B1 is a 6x4 traction mode in which the clutch 70 is in its coupled state and the clutch devices 66 and 68 are in their connected states.For example, the clutch 70 is switched between a decoupling state and a coupling state depending on the driving situation, and for example, the respective coupling device 66, 68 is switched between the connection state and the release state depending on the driving condition. Operating mode B1 is activated, for example, when excessive slip of the vehicle wheels 14 and 16 of the first axle 12 is detected. Operating mode B2 is, for example, a 6x2 standby mode, which is set, for example, in all driving situations where slip is critical. In the second operating mode B2, the clutch 70 is in the decoupling state, while the coupling devices 66 and 68 are in their connection states. As illustrated by the arrows in Fig. 10, starting from operating mode B2, it is possible to switch optionally to operating mode B1 or operating mode B3.Operating mode B3 is a 6x2 mode in which clutch 70 is in its uncoupled state, and in operating mode B3, clutch devices 66 and 68 are in their release states. Operating mode B3 is engaged, for example, in non-critical driving situations with respect to the respective slip of the vehicle wheels 14 and 16, for example, when the motor vehicle is driven on a highway.

[0073] Operating mode B4 is, for example, a synchronization mode, for example for switching to operating mode B1 or operating mode B2. In operating mode B4, clutch 70 is in its coupled state, while clutch devices 66 and 68 are in their released states. For example, switching takes place from operating mode B3 via operating mode B4 to operating mode B1. For example, switching takes place from operating mode B1 to operating mode B2 and vice versa, and for example, switching takes place from operating mode B2 optionally to operating mode B1 or operating mode B3, for example switching from operating mode B1 to operating mode B3 or operating mode B2. Switching takes place from operating mode B3, for example, switching takes place from operating mode B4, for example switching takes place optionally to operating mode B3 or operating mode B1.For example, to switch from operating mode B3 to operating mode B2 or operating mode B1, the switch is made from operating mode B3 via operating mode B4 to operating mode B1 and, if necessary, from this to operating mode B2.

[0074] From Fig. 4 it can be seen that the axle housing 80 has at least one fastening element 120, by means of which the receiving element 92 is fastened in the axle housing 80, in particular in a non-destructively detachable manner.

[0075] 10 tandem axle

[0076] 12 first axis

[0077] 14 vehicle wheel

[0078] 16 vehicle wheel

[0079] 18 Double arrow

[0080] 20 second axis

[0081] 22 vehicle wheel

[0082] 24 vehicle wheel

[0083] 26 Double arrow

[0084] 28 Double arrow

[0085] 30 first differential gear

[0086] 32 first drive shaft

[0087] 34 second differential gear

[0088] 36 second drive shaft

[0089] 38 first drive gear

[0090] 40 second drive gear

[0091] 42 Input gear

[0092] 44 Input gear

[0093] 46 Differential housing

[0094] 48 differential housing

[0095] 50 balance gear

[0096] 52 differential gear

[0097] 54 Output gear

[0098] 56 Output gear

[0099] 58 side shaft

[0100] 60 side shaft

[0101] 62 side shaft

[0102] 64 side shaft

[0103] 66 Coupling device

[0104] 68 Coupling device

[0105] 70 Clutch

[0106] 72 third drive gear

[0107] 74 fourth drive gear

[0108] 76 Input element

[0109] 78 Output element Axle housing inner circumferential surface Receiving space Gear wheel rotation axis Speed ​​sensor Coupling element Receiving element Sensor element Recess Partial area Double arrow Toothing Shaft stub Bearing Bearing Spacer element Assembly Double arrow Connecting device Surroundings Fastening element Outside

Claims

Patent claims 1. Tandem axle (10) for a motor vehicle, comprising: - a drivable first axle (12), which has: o a first differential gear (30), via which first vehicle wheels (14, 16) of the first axle (10) can be driven; and o a first drive shaft (32), by means of which the first differential gear (30) and, via the first differential gear (30), the first vehicle wheels (14, 16) can be driven; - a drivable second axle (20), which has: o a second differential gear (34), via which second vehicle wheels (22, 24) of the second axle (20) can be driven; o a drive gear (40), by means of which the second differential gear (34) and, via the second differential gear (34), the second vehicle wheels (22, 24) can be driven; and o a second drive shaft (36), by means of which the drive gear (40) can be driven; and - a clutch (70) which can be switched between: o a coupling state in which the second drive shaft (36) is coupled to the first drive shaft (32) by means of the clutch (70) in a torque-transmitting manner, whereby the second drive shaft (36) can be driven by the first drive shaft (32) via the clutch (70); and o a decoupling state in which the second drive shaft (36) is decoupled from the first drive shaft (32); characterized in that: - the second axle (20) has an axle housing (80) in which the drive gear (40) rotatable relative to the axle housing (80) is accommodated; and - a speed sensor (88) is provided which is designed to detect a speed of the drive gear (40), said sensor comprising: o a detection element (92) fastened to the axle housing (80); and o a sensor element (94) which is connected in a rotationally fixed manner to the drive gear (40), the speed of which can be detected by means of the receiving element (92), whereby the speed of the drive gear (40) can be detected by means of the speed sensor (88).

2. Tandem axle (10) according to claim 1, characterized in that the sensor element (94) is formed separately from the drive gear (40) and is connected to the drive gear (40) in a rotationally fixed manner.

3. Tandem axle (10) according to claim 1 or 2, characterized in that the drive gear (40) has a toothing (102) and a shaft stub (104) formed integrally with the toothing (102), on which the sensor element (94) is provided.

4. Tandem axle (10) according to claim 3, characterized in that the sensor element (94) at least partially surrounds the shaft stub (104) in the circumferential direction (100) of the shaft stub (104).

5. Tandem axle (10) according to one of the preceding claims, characterized in that: - a spacer element (110) formed separately from the drive gear (40) is connected in a rotationally fixed manner to the drive gear (40), wherein by means of the spacer element (110) two bearings (106, 108), by means of which the drive gear (40) is rotatably mounted on the axle housing (80), are held at a distance from one another in the axial direction (114) of the drive gear (40); and - the sensor element (94) formed separately from the drive gear (40) and separately from the spacer element (110) is connected in a rotationally fixed manner to the Spacer element (110) and is rotationally connected to the drive gear (40) via the spacer element (110).

6. Tandem axle (10) according to claim 5, characterized in that the sensor element (94) at least partially surrounds the spacer element (110) in the circumferential direction (100) of the drive gear (40).

7. Tandem axle (10) according to claim 5 or 6 in its dependent claim 3 or 4, characterized in that the spacer element (110) formed separately from the drive gear (40) and thereby separately from the shaft stub (104) and separately from the toothing (102) is rotationally connected to the shaft stub (104) and completely surrounds the shaft stub (104) in the circumferential direction (100) of the shaft stub (104).

8. Tandem axle (10) according to one of the preceding claims, characterized in that the speed sensor (88) has a connection device (116) by means of which the speed sensor (88) can be or is electrically connected to at least one line, wherein the connection device (116) is arranged outside the axle housing (80).

9. Motor vehicle with a tandem axle (10) according to one of the preceding claims.

10. A method for operating a motor vehicle having a tandem axle (10), in which the tandem axle (10) has: - a drivable first axle (12), which has: o a first differential gear (30), via which first vehicle wheels (14, 16) of the first axle (12) can be driven; and o a first drive shaft (32), by means of which the first differential gear (30) and, via the first differential gear (30), the first vehicle wheels (14, 16) can be driven; - a drivable second axis (20) comprising: o a second differential gear (34), via which second vehicle wheels (22, 24) of the second axle (20) can be driven; o a drive gear (40), by means of which the second differential gear (34) and, via the second differential gear (34), the second vehicle wheels (22, 24) can be driven; and o a second drive shaft (36), by means of which the drive gear (40) can be driven; and - a clutch (70) which can be switched between: o a coupling state in which the second drive shaft (36) is coupled to the first drive shaft (32) by means of the clutch (70) in a torque-transmitting manner, whereby the second drive shaft (36) can be driven by the first drive shaft (32) via the clutch (70); and o a decoupling state in which the second drive shaft (36) is decoupled from the first drive shaft (32); characterized in that: - the second axle (20) has an axle housing (80) in which the drive gear (40) rotatable relative to the axle housing (80) is accommodated; - a speed sensor (88) is provided, by means of which a speed of the drive gear (40) is detected, wherein the speed sensor (88) comprises: o a detection element (92) fastened to the axle housing (80); and o a sensor element (94) connected in a rotationally fixed manner to the drive gear (40), the speed of which is detected by means of the receiving element (92), whereby the speed of the drive gear (40) is detected by means of the speed sensor (88); and - the motor vehicle is operated as a function of the speed of the drive gear (40) detected by the speed sensor (88).

Images