DE102015122801B4 - Driven axle arrangement - Google Patents

Abstract

Use of a drivable axle arrangement (11),
the two half-axles (15, 15') for driving a respective wheel hub (61, 61') and a differential gear (19) provided between the half-axles (15, 15') for distributing a drive torque of a motor to the two half-axles (15, 15'), wherein the differential gear (19) has an input (21) for receiving the drive torque and two outputs (23, 23') for outputting the drive torque to a respective half-axle (15, 15'), wherein the half-axles (15, 15') have a respective clutch (31, 31') and a respective reduction gear (33, 33') with an input element (35) assigned to the differential gear (19) and an output element (51) assigned to the respective wheel hub (61, 61'), which determines a rotational speed of the output element (51) relative to the input element (35) is translated into slow speed, wherein the respective clutch (31, 31') is arranged such that the respective wheel hub (61, 61') can be selectively connected to or separated from the respective output (23, 23') of the differential gear (19) by means of the respective clutch (31, 31'),
in a trailer having a plurality of axles and designed to be towed by a tractor.

Description

The invention relates to a drivable axle arrangement or the use of such a drivable axle arrangement.

A drivable axle arrangement with a differential gear for distributing a drive torque to two half-axles, furthermore with clutches and with reduction gears on the half-axles is known from the published application DE 199 61 096 A1 and from the patent specification US 6 024 182 A A comparable axle arrangement is also known from the published DE 31 31 952 A1 and from the disclosure document US 2014 / 0 216 189 A1 known.

The field of special-purpose vehicle construction encompasses vehicles or vehicle modules, such as trailers in particular, that have a plurality of axles to distribute the weight of a load across several axles arranged one behind the other in the direction of travel of the vehicle. Each of these axles can, for example, have one or more wheels at its two respective ends, e.g., a dual-wheel arrangement.

When transporting over uneven ground, the wheels must be adjusted as individually as possible to prevent individual wheels from losing contact with the ground, which would place increased stress on the remaining wheels, subject the axles to strong bending moments, and destabilize the vehicle's overall motion. It is therefore advisable to mount the individual axles in a movable and/or spring-loaded manner in a substantially vertical direction. However, such mobility results in limitations in terms of installation space.

If the vehicle is a trailer, it is usually powered by a tractor to which the trailer is coupled. The trailer is therefore merely towed. For example, if an incline has to be negotiated, such a towing drive may not be sufficient. In such a case, or to generally improve traction, particularly in difficult terrain, it is therefore advantageous if the axles of the trailer (or at least some of the axles) themselves can be directly driven. Directly driven axles can also achieve a self-propelled function of a trailer, which can then also be driven without a towing vehicle. For the drive, motors, in particular hydraulic motors or electric motors, can be provided or connectable to the trailer or axles. These motors are supplied, for example, with hydraulic pressure or electricity from a central drive unit. However, the trailer can also have a common motor for several drivable axles, the drive torque of which is transmitted and distributed to the multiple axles.

Direct-drive axles can therefore be used to tackle transport sections that require high torque and therefore, or for other reasons, cannot be handled by towing. Nevertheless, towing can offer advantages over direct axle drive, particularly with regard to travel at comparatively high speeds and/or on level ground, because better dynamics can be achieved, for example, by using different gears.

While the driven axles can, in principle, be de-driven and towed instead, this poses the problem that the drive and/or transmission components of the driven axles can be subjected to significant wear or damage due to high speeds during towing. One option for using directly driven axles in towing mode is to raise the directly driven axles during high-speed travel (so-called "lifting") to protect them from over-rotation. However, such functionality requires additional resources, which complicates the design and increases costs.

It is therefore an object of the invention to provide a drivable axle arrangement which avoids the aforementioned disadvantages and has a compact design in order to enable vehicle modules which can be used either in towing mode or by means of their own direct drive.

The object is achieved by the use of a drivable axle arrangement in a trailer having a plurality of axles and designed to be towed by a tractor, with the features of claim 1.

The drivable axle assembly comprises two half-axles for driving a respective wheel hub, wherein the two half-axles are preferably arranged in a housing of the axle assembly and aligned coaxially with each other. The axle assembly further comprises a differential gear for distributing a drive torque of a (particularly connectable or permanently connected) motor to the two half-axles, wherein the differential gear has an input for receiving the drive torque and two outputs. gears for outputting (a respective portion of) the drive torque to the respective half-axle. The half-axles have a respective clutch and a respective reduction gear with an input element assigned to the differential gear and an output element assigned to the wheel hub, which reduces the speed of the output element relative to the input element. The respective clutch is arranged such that the respective wheel hub can be selectively connected to or separated from the respective output of the differential gear by means of the respective clutch. In other words, the half-axles have a respective clutch which is arranged between the differential gear and the wheel hub driven by the respective half-axle.

In order to generate particularly high torques on the driven axle assembly, a reduction gear is provided on each of the semi-axles – for example, on the wheel hubs or in the area of the wheel hubs. This creates the problem that, during towing, the already high speed of the wheels rolling on the ground is translated to even higher speeds by the reduction gear (which operates in reverse during towing, thus causing a gear increase). This could cause increased wear or even damage to the differential gear or the engine. However, this can be prevented by decoupling the differential gear from the wheel hubs using the couplings provided on the semi-axles. It is preferred if the respective clutch is provided between the differential gear and the respective reduction gear, so that, on the one hand, the input element of the respective reduction gear can be selectively connected to or separated from the respective output of the differential gear by means of the respective clutch, and, on the other hand, the output element of the respective reduction gear is, in particular permanently, connected to or can be connected to the respective wheel hub in a driving manner (the latter if the wheel hubs are not part of the axle arrangement, but the axle arrangement merely has means for fastening the actual wheel hubs). In principle, however, the respective clutch can also be provided on the other side of the respective reduction gear, i.e. between the respective reduction gear and the respective wheel hub. In this case, the output element of the respective reduction gear can be selectively connected to or separated from the respective wheel hub in a driving manner by means of the respective clutch.

In the drivable axle arrangement, a respective clutch, in particular a pure separating clutch, is provided in each half-axle, by means of which the drive connection of the differential gear to the respective wheel hub can be interrupted as needed. If the axle arrangement is not driven by the aforementioned engine but is used in towing mode, the respective clutch can be opened so that wheels arranged on the axle arrangement rotate and thus introduce a torque into the axle arrangement in the opposite direction. However, the rotation is not transmitted to the differential gear and beyond to the engine, but ends at the opened separating clutch.

Although the reduction gear is designed to translate the rotation of the wheels to higher speeds in this reversed torque transmission direction in towing operation, the respective clutch, depending on its position within the respective semi-axle, can prevent the torque from reaching the respective reduction gear at all or prevent the speeds increased by the respective reduction gear from reaching the differential gear and the engine, so that in any case these components of the axle arrangement are not subjected to excessive loads.

Advantageous embodiments and further developments of the invention are explained below.

In this case, it is advantageous, for example due to the available installation space, to provide the aforementioned respective clutch between the differential and the reduction gear. It can then be accommodated in particular in a central region of the axle arrangement, which can have a larger cross-section compared to the end regions of the axle arrangement, where the respective wheel hubs are arranged. Furthermore, arranging the clutch on the drive side of the reduction gear has the advantage over arranging it on the output side that a control device for the respective clutch can be arranged in the aforementioned central region and the actuation of the respective clutch then does not need to take place via the respective reduction gear, which may be difficult to achieve. A further advantage of this clutch arrangement is that a rotary movement generated during towing and introduced by the respective wheel hub into the respective semi-axle is translated by the reduction gear to higher speeds but to lower torque. Therefore, the clutch on the differential side of the reduction gear can be dimensioned more lightly than if it were arranged on the wheel side to reduction gear, where it would have to be designed for higher torques.

While in this embodiment the respective reduction gear is only selectively connected to other gear elements, specifically the output of the differential gear, on the input side due to the respective clutch, the respective reduction gear is preferably permanently connected to the wheel-side end of the respective half-axle on the output side.

This wheel-side end, to which the drive torque is transmitted in the case of a directly driven axle arrangement, can be formed by the output element of the reduction gear itself, can be designed as a flange for fastening respective wheel hubs (and can also be formed integrally with the output element of the respective reduction gear) or can be formed by a respective wheel hub or respective wheel hubs.

The two half-axles of the axle assembly preferably not only each have the elements connected to one another in the aforementioned manner (namely, the respective clutch and the respective reduction gear), but are preferably designed essentially corresponding to one another, in particular mirror-symmetrically or point-symmetrically to one another. This advantageously allows the use of corresponding components for both half-axles, thereby making production simpler and more cost-effective.

According to a preferred embodiment, the respective reduction gear is designed as a planetary gear comprising a sun gear, a planet carrier and a ring gear, wherein an arrangement of planet gears is rotatably mounted on the planet carrier and meshes with the sun gear and the ring gear, wherein the ring gear is designed to be stationary, that is to say rigidly connected directly or indirectly to a housing of the axle arrangement or even directly on the housing, in particular integrally formed in the housing.

Furthermore, it is preferred if the sun gear of this planetary gear constitutes the aforementioned input element of the respective reduction gear, and the planet carrier of the planetary gear constitutes the aforementioned output element of the respective reduction gear. In this way, with comparatively few components and a compact arrangement, a drive torque introduced at the input element can be output at the output element of the respective reduction gear at a reduced speed and increased torque. By using a high-speed motor, high torques can be generated to drive the wheel hubs.

However, with regard to the reduction gear, other configurations are generally possible that slow down the speed of an output element relative to the speed of an input element.

According to a further preferred embodiment, the half-axles further comprise a respective axle shaft, wherein the input element of the respective reduction gear is drivingly connected (or connectable) to the respective output of the differential gear via the respective axle shaft and, if applicable, via the respective clutch. Thus, in the respective half-axles, an intermediate element formed by the respective axle shaft is provided between the respective output of the differential gear and the input element of the respective reduction gear, which serves to transmit the drive torque from the differential gear to the respective reduction gear.

According to a preferred development, the respective axle shaft is or can be connected in a driving manner to the respective output of the differential gear and to the input element of the respective reduction gear. The respective axle shaft is preferably permanently connected in a driving manner to the respective output of the differential gear and can be selectively connected in a driving manner to the input element of the respective reduction gear by means of the respective clutch. In other words, the respective clutch is effective between the respective axle shaft and the input element of the respective reduction gear. For this purpose, for example, at least a part of the respective clutch, for example a sliding sleeve or a gearing, can be connected in a rotationally fixed manner to the respective axle shaft and can be connected in a non-positive, frictional and/or positive manner to the input element of the respective reduction gear, in particular to a clutch section provided on the input element, such as a gear or a counter-gearing.

To actuate the respective clutch between a coupling and a separating position, the respective clutch or at least a part of the clutch can be arranged axially movable on the respective axle shaft. Alternatively, the respective clutch or at least a part of the clutch can also be axially rigidly connected to the respective axle shaft, but can be axially movable together with the respective axle shaft between a coupling and a separating position.

According to a further advantageous embodiment, the respective output of the differential gear has a hollow shaft section, wherein the respective axle shaft is partially, in particular at one end, non-rotatably received in the hollow shaft section of the output of the differential gear. The non-rotatably connected axle shaft to the output of the differential gear can be achieved, for example, via a spline or a serration. By receiving the respective axle shaft, in particular an end section of the respective axle shaft, in the hollow shaft section of the respective output of the differential gear, the respective axle shaft can be mounted at least with its axially inner end on this output. The output, in turn, can be mounted as part of the differential gear, for example via the differential carrier, in particular indirectly via the tooth engagement with the differential bevel gears of the differential gear, relative to the housing of the axle arrangement via a bearing device, preferably a rolling bearing device. Thus, the respective output can be mounted exclusively indirectly, at least in the radial direction. In particular, the respective axle shaft is rotatably mounted indirectly on the housing via the output of the differential gear. The aforementioned bearing device simultaneously supports the differential gear (directly) and at least one (axially inner) end section of the respective axle shaft (indirectly). Therefore, such an arrangement can reduce the total number of required bearing devices.

Alternatively or additionally, it is advantageous if the input element of the respective reduction gear has a hollow shaft section, wherein the respective axle shaft is partially received, in particular with an end opposite the aforementioned end, in the hollow shaft section of the input element of the respective reduction gear. This other end is therefore in particular the axially outer end of the respective axle shaft. In such an embodiment, the respective axle shaft can thus be at least partially supported by being received in the hollow shaft section of the input element of the respective reduction gear. In particular, the respective axle shaft can be rotatable relative to this hollow shaft section in which it is received and can only be connected for common rotation with this hollow shaft section when the respective clutch is closed. A direct interaction of the axle shaft with the hollow shaft section of the input element, for example by means of a spline or serration, as in the aforementioned embodiment with the hollow shaft section of the respective differential gear output, therefore preferably does not occur.

In this context, it is advantageous, particularly in order to ensure good rotatability and relative support of the respective axle shaft with respect to the hollow shaft section of the input element of the respective reduction gear, if the respective axle shaft is rotatably mounted in the hollow shaft section of the input element of the respective reduction gear via a bearing device. This bearing device is in particular a rolling bearing device. Alternatively, a plain bearing can also be provided. This bearing device, which is provided between the axle shaft and the hollow shaft section of the input element of the respective reduction gear and is therefore not directly supported on the housing, is preferably designed for relatively high speeds in order to allow the input element of the respective reduction gear (which then acts as the output) to rotate reliably freely relative to the respective axle shaft at the resulting high speeds during drag operation of the axle arrangement, without transmitting torque to the respective axle shaft.

The respective axle shaft is mounted, in particular, radially on the hollow shaft section of the respective output of the differential gear or the hollow shaft section of the input element of the respective reduction gear. For axial support of the respective axle shaft, plain bearing thrust washers can also be provided at its ends, which can be arranged on or in the differential gear or the respective reduction gear.

In a combination of the aforementioned embodiments, the respective axle shaft can be received with an axially inner end portion in the hollow shaft portion of the respective output of the differential gear and thus supported therein, and can be received with the opposite, axially outer end portion in the hollow shaft portion of the input element of the respective reduction gear and thus supported therein. Such a design advantageously eliminates the need for a separate direct bearing for the respective axle shaft on the housing of the axle assembly, thereby saving installation space and costs.

In principle, it is preferred if the respective axle shaft is mounted exclusively indirectly on a housing of the axle arrangement, ie the respective axle shaft is mounted exclusively on the housing via other components of the axle arrangement mounted. Thus, for a rotatable mounting of the axle shafts, there is no need for bearing devices specifically provided for the respective axle shaft, in particular rolling bearings. The indirect mounting of the respective axle shaft can, for example, be achieved as described above by a respective end section of the respective axle shaft being received in a hollow shaft section of the respective output of the differential gear or the input element of the respective reduction gear. The indirect mounting of the respective axle shaft can, in principle, also be achieved in another way, as long as no bearing device, in particular no rolling bearing device, is provided between the respective axle shaft and the housing, supporting the respective axle shaft directly on the housing.

The input element of the respective reduction gear is also preferably rotatably mounted exclusively indirectly on the housing. The indirect mounting of the input element of the respective reduction gear can result, on the one hand, from the arrangement of the input element in the respective reduction gear, for example, from the design as a sun gear of a planetary gear, and, on the other hand, from the input element being rotatably mounted on the respective axle shaft via the aforementioned bearing device, which is preferably a rolling bearing device. Because elements of the axle arrangement partially support one another and thus support one another, the number of required bearing devices, in particular rolling bearing devices, is advantageously reduced.

The described exclusively indirect bearing arrangement, in particular of the respective axle shaft, is to be understood as referring to a radial bearing arrangement, in particular a rolling bearing arrangement. The fact that guides or other types of support elements (e.g., thrust washers) can be provided between a respective element and the housing of the axle assembly does not fundamentally preclude an indirect bearing arrangement.

According to a further advantageous embodiment, the respective clutch is designed as a positive-locking clutch, for example as a claw clutch or having a sliding sleeve. For example, an input-side (i.e., differential gear side) part of the respective clutch can be connected to the respective axle shaft in a rotationally fixed and preferably axially displaceable manner, while an output-side (i.e., wheel hub side) part of the respective clutch is connected to the input element of the respective reduction gear in a rotationally fixed and preferably rigid manner. This results in particularly simple actuation of the respective clutch from the center of the axle arrangement, i.e., from the direction of the differential gear. Alternatively, the input-side part of the respective clutch can be connected to the respective axle shaft in a rotationally fixed and rigid manner, but can be axially displaceable together with the respective axle shaft. For example, the input-side part can be a sliding sleeve and the output-side part a corresponding gear. However, it is generally also possible for an input-side (i.e., differential gear side) part of the respective clutch to be rigidly connected to the respective axle shaft, while an output-side (i.e., wheel hub side) part of the respective clutch (e.g., sliding sleeve) is connected to the input element of the respective reduction gear in a rotationally fixed and axially movable manner. By using a positive-locking clutch, a reliable transmission of the drive torque is achieved when the respective clutch is engaged, while a reliable separation occurs when the respective clutch is disengaged, so that no drive torque is transmitted across the clutch.

According to an alternative embodiment, the respective coupling can also be designed as a force-locking coupling.

Furthermore, it is advantageous if a respective switching device for switching the respective clutch is assigned to the respective clutch. This gives rise to the particular problem that the switching device cannot be arranged at any desired location on the axle arrangement, on the one hand for reasons of installation space and on the other hand in order to be able to control it in a suitable manner. In particular, if the axle arrangement is designed for a pivotably mounted swing axle, a respective free space is required between the wheel hubs and the central differential gear for the swinging movement of the axle arrangement, and a switching signal is preferably transmitted centrally to the axle arrangement, for example in the region of the pivotable mounting of the swing axle, so that a switching device or at least one actuator of the switching device is preferably arranged in a central region of the axle arrangement.

It is further preferred if the respective switching device has an actuator and a transmission element in order to transmit a switching stroke of the actuator to the respective clutch by means of the transmission element, wherein the transmission element has a first end associated with the actuator and a second end associated with the respective clutch, and wherein the first end of the transmission element is located, in particular axially, closer to the differential gear and/or is arranged radially further away from the axis of rotation of the axle arrangement than the second end. In particular, said first end of the transmission element is arranged axially, i.e. viewed along a rotation axis of the axle arrangement, closer to the differential gear than the second end. In other words, the first end of the transmission element and thus the actuator can be offset axially inwards relative to the second end of the transmission element and thus the respective clutch. In addition, the first end of the transmission element and thus the actuator can also be offset radially outwards relative to the second end of the transmission element and thus the respective clutch with respect to the axis of rotation of the axle arrangement.

Such an arrangement has the advantage that a respective shift stroke can be transmitted by the transmission element over a certain distance and/or along angled paths. This allows the actuator to be positioned more flexibly within the axle arrangement and does not need to be located in the immediate vicinity of the respective clutch. Particularly when installation space is severely limited, the clutch and actuator can therefore be positioned relatively flexibly, as long as the transmission element, which requires comparatively little installation space, transmits the shift stroke from the actuator to the respective clutch.

For example, such a switching device enables arrangements in which the actuator of the respective switching device is arranged closer to the differential gear than to the respective clutch. Furthermore, it is possible for the first end of the respective transmission element to be radially further away from the axis of rotation of the axle assembly than the second end. This makes it possible, in particular, to arrange the actuator in a central region of the axle assembly with a comparatively large cross-section, while the respective clutch can also be arranged in an area where, for example, the wheel hubs are mounted and which therefore has a comparatively small diameter.

In principle, any device capable of generating a switching stroke can be considered as an actuator. This could be, for example, a hydraulic or pneumatic actuator.

In an exemplary axle arrangement, the clutch, in particular, can be arranged axially and radially at least partially within a wheel hub arranged on the respective semi-axle with respect to the axis of rotation of the axle arrangement. The wheel hub can also be an arrangement of two parallel and essentially directly adjacent hubs for a twin-wheel arrangement. The actuator of the respective shifting device, however, can be arranged axially outside the aforementioned wheel hub of the respective semi-axle.

According to a preferred embodiment, the transmission element has a joint arrangement. The joint arrangement can, for example, comprise one or more pivoting or rocker arms, which can be pivotably mounted relative to the housing. In this way, the switching stroke can be transmitted particularly flexibly and, unlike with an exclusively longitudinally displaceable transmission element, such as a push rod, also along curved paths within the axle arrangement.

Regardless of the specific design of the switching devices of both half-axles, a further advantageous embodiment provides that the switching devices for switching the respective clutch of the two half-axles are designed to switch both clutches together. Such a switching mode, in which both clutches of the axle assembly are switched together, can be provided optionally. Preferably, however, the two clutches can only be switched together to ensure that both clutches are always open during towing operation of the axle assembly and that both clutches are always closed in a directly driven axle assembly.

In order to switch the two clutches exclusively together, according to an advantageous embodiment it can be provided that a common switching device is assigned to the two clutches, which has an actuator common to both clutches and at least one respective transmission element for the two clutches in order to transmit a switching stroke of the actuator to the respective clutch by means of the respective transmission element. In this case - in a corresponding manner as explained above - the respective transmission element can have a first end assigned to the actuator and a second end assigned to the respective clutch, wherein the first end of the respective transmission element is arranged, in particular axially, closer to the differential gear and/or radially further from the axis of rotation of the axle arrangement than the second end. The respective transmission element can in particular comprise a joint arrangement.

According to a further preferred embodiment, an input A speed sensor is provided to detect an input speed of the input of the differential gear, wherein a respective output speed sensor is provided on each half-axle to detect an output speed of the respective clutch, and wherein a control device is assigned to the axle arrangement, which is designed to close the respective clutch only when the difference between the detected input speed of the input of the differential gear and the detected output speed of the respective clutch is less than a threshold value. The input speed sensor therefore detects an engine-side input speed at the input of the differential gear. Since the differential gear distributes the drive torque between its two outputs, the input speed thus detected corresponds to an average input speed of the two respective clutches. The output speed detected on the output side, i.e., wheel side, of the respective clutch by means of the respective output speed sensor can then be compared with this average input speed of the respective clutch to ensure that the respective clutch is only closed, i.e., engaged, for example, when the speed difference is less than the stated threshold value, in particular at least almost zero. In this way, the respective clutch is essentially only closed synchronously, i.e. at almost identical input and output speeds.

If an input speed sensor is provided at the input of the differential gear, one input speed sensor is sufficient for both respective clutches, which is advantageous in terms of both cost and installation space. As an alternative to the above embodiment, however, it is advantageous with regard to improved detection of a synchronous state at the individual respective clutches if a respective input speed sensor is provided on both half-axles in order to detect an input speed of the respective clutch. In this alternative embodiment, a respective output speed sensor is also provided on both half-axles in order to detect an output speed of the respective clutch, wherein a control device is assigned to the axle arrangement which is designed to close the respective clutch only when the difference between the detected input speed of the respective clutch and the detected output speed of the respective clutch is less than a threshold value. Instead of an average input speed for both clutches, a separate input speed is determined for each of the clutches.

In this embodiment with two input speed sensors, the control device can further be designed to close both clutches together only when both the difference between the detected input speed and the detected output speed of one respective clutch is less than a first threshold value and the difference between the detected input speed and the detected output speed of the other respective clutch is less than a second threshold value, wherein the first and the second threshold value are preferably identical.

According to an advantageous embodiment, the axle assembly is designed as a pendulum axle assembly and has a fastening device by means of which the axle assembly can be fastened to a support device of a vehicle in a pendulum-like manner. This fastening device is provided in particular in a central region of the axle assembly and is preferably equidistant from the respective wheel-hub ends of the two half-axles. The fastening device functions in particular as a pivot joint with a rotational axis oriented horizontally and/or parallel to the vehicle's longitudinal axis.

Furthermore, it is preferred if the axle assembly includes the aforementioned motor, which can be a hydraulic motor or an electric motor. The motor can be arranged within the housing of the axle assembly, thereby providing particularly good external protection. Alternatively, the motor can also be arranged outside the housing, for example, attached to an outer side of the housing, e.g., flanged, to drive the input element of the differential gear, so that the motor and the rest of the axle assembly can be connected to one another in a modular manner, which can be advantageous with regard to interchangeability and/or maintenance of the motor.

• 1 zeigt in schematischer Darstellung eine Ausführungsform einer antreibbaren Achsanordnung.
• 2 zeigt eine vergrößerte Teilansicht der in 1 dargestellten Ausführungsform.
• 3 zeigt eine weitere Ausführungsform einer antreibbaren Achsanordnung in schematischer Darstellung.
• 4 zeigt eine weitere Ausführungsform einer antreibbaren Achsanordnung in schematischer Darstellung.

The invention is explained in more detail below by way of example only with reference to the figures.

• 1 shows a schematic representation of an embodiment of a drivable axle arrangement.
• 2 shows an enlarged partial view of the 1 illustrated embodiment.
• 3 shows a further embodiment of a drivable axle arrangement in a schematic representation.
• 4 shows a further embodiment of a drivable axle arrangement in a schematic representation.

In 1 is an exemplary embodiment of a drivable axle arrangement 11 schematic The axle assembly 11 comprises a housing 13 in which two semi-axles (first semi-axle 15 and second semi-axle 15') are arranged. The semi-axles 15, 15' are aligned at least substantially coaxially with one another in that their main axes of rotation are aligned. Furthermore, the semi-axles 15, 15' are configured substantially correspondingly to one another and are constructed symmetrically to a mirror surface that runs perpendicular to the longitudinal extent of the axle assembly 11 through its center.

The axle assembly 11 has a motor interface 17 for connecting a motor (not shown) in a central region on an outer side of the housing 13. The motor interface 17 has, in particular, a flange for a drive-effective connection of the motor. The motor can be a hydraulic motor or an electric motor, for example, and can be designed to be connected to the motor interfaces 17 of several essentially similar axle assemblies 11 in order to drive them in parallel.

A drive torque from the engine can be introduced into the axle assembly 11 via the engine interface 17. To distribute the drive torque between the two half-axles 15, 15', the axle assembly 11 has a differential gear 19, which is designed as a bevel gear differential and has an input 21 for receiving the drive torque, which is formed by a bevel gear that meshes with a ring gear 22 formed on the differential carrier. Via two outputs (first output 23 and second output 23'), which are formed by output bevel gears, a respective portion of the drive torque is output from the differential gear 19 to the respective half-axle 15 or 15', wherein speed compensation can be achieved via several differential bevel gears 24.

The two outputs 23, 23' extend coaxially and opposite each other in the direction of the respective semi-axles 15, 15'. The differential gear 19, including the differential carrier and ring gear 22, is supported relative to the housing 13 by a bearing device 27 designed as a rolling bearing, whereby the two outputs 23, 23' are also indirectly supported radially (via their meshing with the differential bevel gears 24). Axial support of the two outputs 23, 23' can be provided, for example, by plain bearing thrust washers (not shown).

Both half-axles 15, 15' comprise a respective axle shaft (first axle shaft 29 and second axle shaft 29', respectively), a respective clutch (first clutch 31 and second clutch 31', respectively) and a respective reduction gear (first reduction gear 33 and second reduction gear 33', respectively).

As can be seen particularly in the enlarged partial view of the 2 As can be seen, the respective axle shaft 29, 29' is received with an end section, namely the axially inner end with respect to the longitudinal extent of the axle arrangement 11, in a hollow shaft section 25 of the respective output 23, 23' of the differential gear 19. In this way, the respective axle shaft 29, 29' of a respective half-axle 15, 15' is only indirectly rotatably mounted relative to the housing 13 via the hollow shaft section 25, the tooth engagement between the output 23, 23' and the differential bevel gears 24, as well as the bearing device 27 of the differential gear 19 (in particular with respect to a rolling bearing). The respective axle shaft 29, 29' is connected via a tooth engagement for common rotation with the hollow shaft section 25 of the respective output 23, 23' of the differential gear 19.

Similar to the respective output 23, 23' of the differential gear 19, an input element 35 of the respective reduction gear 33, 33' also has a hollow shaft section 37. The end section of the respective axle shaft 29, 29' opposite the aforementioned end section, i.e., the axially outer end relative to the longitudinal extent of the axle assembly 11, is received in this hollow shaft section 37 of the input element 35 of the respective reduction gear 33, 33'. A further bearing device 39 is provided between the respective axle shaft 29, 29' and the input element 35 of the respective reduction gear 33, 33' for their mutual support. This bearing device is again designed as a rolling bearing, but can alternatively also be designed as a plain bearing.

Thus, although the respective axle shaft 29, 29' is rotatably mounted at both ends, no direct mounting of the respective axle shaft 29, 29' on the housing 13 is provided. Instead, the respective axle shaft 29, 29' is only rotatably mounted on the housing 13 indirectly via the hollow shaft section 25 of the respective output 23, 23' of the differential gear 19, and is supported relative to the respective reduction gear 33, 33' by being mounted in the hollow shaft section 37 of the input element 35. This concerns the radial mounting of the respective axle shaft 29, 29'. For axial support, plain bearing thrust washers (not shown) are also provided at the ends of the respective axle shaft 29, 29'.

The respective reduction gear 33, 33' can in turn be supported on the housing 13 without roller bearings, for example by being designed as a plate A gear train is formed, the ring gear of which is integrally formed in the housing 13, as will be described below. In this way, the axle assembly 11 can have a particularly small number of bearing devices 27, 39, in particular rolling bearing devices, which is advantageous in terms of reduced installation space, reduced complexity, and lower costs.

The respective axle shaft 29, 29' is connected to the hollow shaft section 25 of the respective output 23, 23' of the differential gear 19 in a rotationally fixed manner, i.e., for common rotation, via a spline, so that the drive torque output by the differential gear 19 is transmitted proportionally to the two axle shafts 29, 29'. However, the respective axle shaft 29, 29' and the hollow shaft section 37 of the input element 35 of the respective reduction gear 33, 33' are not directly connected to one another in a rotationally fixed manner, but are freely rotatable relative to one another due to the additional bearing device 39 arranged therebetween, so that the drive torque from the respective axle shaft 29, 29' is not transmitted directly to the respective reduction gear 33, 33'.

A sliding sleeve 41 of the respective clutch 31, 31' is rigidly connected to the respective axle shaft 29, 29', which is consequently driven to rotate by the drive torque via the differential gear 19 and the respective axle shaft 29, 29'. The sliding sleeve 41 can be axially displaced together with the respective axle shaft 29, 29' mounted in the hollow shaft sections 25, 37 in order to selectively engage positively with a gear 43 provided on the input element 35 of the respective reduction gear 33, 33' (cf. 2 ). When such an engagement is present, the respective clutch 31, 31' is closed and transmits the drive torque from the respective axle shaft 29, 29' to the input element 35 of the respective reduction gear 33, 33'. Alternatively to the illustration according to 1 and 2 the sliding sleeve 41 can be connected to the respective axle shaft 29, 29' in a rotationally fixed but axially displaceable manner.

To ensure that the respective clutch 31, 31' is only closed when the input speed, i.e. the speed of the respective axle shaft 29, 29', and the output speed, i.e. the speed of the input element 35 of the respective reduction gear 33, 33', are almost identical, speed sensors 45, 47, 47', 49, 49' are provided, which are in 1 are shown.

Specifically, an input speed sensor 45 is arranged at the input 21 of the differential gear 19 to detect an input speed of the differential gear 19. From this, an average input speed of the two clutches 31, 31' can then be determined. Alternatively, instead of the aforementioned input speed sensor 45, a respective input speed sensor (first input speed sensor 47 or second input speed sensor 47') is provided on both half-axles 15, 15', which is arranged on the respective axle shaft 29, 29' to detect the input speed of the respective clutch 31, 31' directly and separately for both clutches 31, 31'. These two alternatives are shown in 1 shown superimposed.

Furthermore, in both of the aforementioned alternatives, the aforementioned speed sensors 45, 47, 47', 49, 49' on both semi-axles 15, 15' comprise a respective output speed sensor (first output speed sensor 49 or second output speed sensor 49'), which is arranged on an output element 51 of the respective reduction gear 33, 33' in order to detect the output speed of the respective clutch 31, 31' via the known, fixed reduction ratio of the respective reduction gear 33, 33'. Alternatively, the respective output speed sensor 49, 49' can also be arranged directly on the input element 35 of the respective reduction gear 33, 33', so that a conversion according to the reduction ratio is omitted. This alternative is not shown in the figures.

The speed sensors 45, 47, 47', 49, 49' are connected to a control device 53, which detects the detected input speeds and output speeds, converts them if necessary, and controls the clutches 31, 31' depending on a (respective) speed difference thus determined. For this purpose, the control device 53 can be connected to respective switching devices (first switching devices 55 or second switching devices 55'), which actuate the clutches 31, 31', but in the 1 and 2 are not shown (see further embodiment in 3 ).

The respective reduction gear 33, 33' is designed as a planetary gear comprising a sun gear as the aforementioned input element 35, a planet carrier as the aforementioned output element 51, and a ring gear 57, which is rotationally fixedly connected to the housing 13 because it is integrally formed in the housing 13. A plurality of planet gears 59 are rotatably mounted on the planet carrier 51 and mesh with the sun gear 35 and the ring gear 57. The toothing of the gears 35, 57, 59 is designed such that a converted drive torque transmitted to the sun gear 35 is output at the planet carrier 51 at a reduced speed and increased torque.

As the output element 51 of the respective reduction gear 33, 33', the planetary carrier 51 ultimately outputs the converted drive torque to the respective wheel hubs (first wheel hub 61 or second wheel hub 61') in order to drive wheels arranged on the axle assembly 11, which may also be twin wheel arrangements, via the axle assembly 11. A respective wheel hub 61, 61' may be flanged to the output element 51 of the respective reduction gear 33, 33' directly or indirectly, e.g., via a further respective shaft. The respective wheel hub 61, 61' may also be formed integrally with the output element 51, as shown in 3 is shown. Ultimately, however, regardless of the specific coupling, the respective wheel hub 61, 61' is permanently connected to the respective reduction gear 33, 33' in a drive-effective manner and cannot be selectively separated from the reduction gear 33, 33', for example via a clutch.

As in the embodiment in 3 As shown, a respective switching device 55, 55' is assigned to the respective clutch 31, 31', which comprises an actuator 65 for generating a switching stroke and a transmission element 67 for transmitting the switching stroke to the respective clutch 31, 31'. The transmission element 67 is designed as a joint arrangement comprising push rods 69 and a rocker arm 71 in order to transmit the switching stroke of the actuator 65 of the respective switching device 55, 55' along an angled path, possibly restricted, for example, by the shape of the housing 13, from the actuator 65 to the respective clutch 31, 31'.

By means of the transmission element 67, the respective switching device 55, 55' can therefore be arranged at a distance from the respective clutch 31, 31', particularly with regard to the available installation space. For example, the end of the transmission element 67 associated with the actuator can be arranged closer to the differential gear 19 and/or (as in 3 shown) be arranged radially further away from the axis of rotation of the axle arrangement 11 than the end assigned to the respective coupling 31, 31'. Alternatively to the 3 In the arrangement shown, the respective clutch 31, 31' can also be arranged in an area of the respective half-axle 15, 15' surrounded by the respective wheel hub 61, 61', which therefore has comparatively less installation space than a central area not surrounded by the wheel hubs 61, 61', in which the differential gear 19 can be accommodated and which can also have space for the actuators 65 of the switching devices 55, 55'.

The actuators 65 of the 3 The embodiment shown is designed as hydraulic actuators, but can in principle also be of a different type, e.g. electrically or pneumatically. In addition, the actuators 65 are controlled by a common control device 53 (in 3 not shown, cf. 1 ), wherein the two clutches 31, 31' are always opened or closed together, and wherein the closing of the clutches 31, 31' takes place depending on whether a speed difference between an input speed and an output speed of the respective clutches 31, 31' is zero or at least below a threshold value.

In contrast to the 1 The embodiment shown in the 3 In the embodiment shown, the sliding sleeve 41 of the respective clutch 31, 31' is not rigidly connected to the respective axle shaft 29, 29', but is only connected in a rotationally fixed manner, but is otherwise mounted so as to be axially movable relative to the respective axle shaft 29, 29'. This can be achieved, for example, by the sliding sleeve 41 interacting with the respective axle shaft 29, 29' via a spline. When the respective clutch 31, 31' is engaged, only the sliding sleeve 41 is axially displaced, but not the respective axle shaft 29, 29'.

Nevertheless, the sliding sleeve 41 is thereby selectively brought into positive and driving engagement with the gear 43, so that the drive torque which drives the respective axle shaft 29, 29' can be transmitted via the sliding sleeve 41 and via the gear 43 to the input element 35 of the respective reduction gear 33, 33'.

The 3 The illustrated embodiment of an axle arrangement 11 can be designed as a pendulum axle arrangement. For this purpose, the axle arrangement 11 can have a fastening device (not shown), which is designed, for example, as an extension of a wall of the housing 13 in the form of a solid tab and by means of which the axle arrangement can be fastened in a pendulum-movable manner to a support device of a vehicle (not shown). The fastening device thus acts as a rotary joint, which enables the axle arrangement 11 to pivot about a pendulum axis defined by the fastening device and oriented perpendicular to the axis of rotation of the axle arrangement 11 (perpendicular to the plane of the illustration).

Despite the compactness of such an axle arrangement 11, especially when it has twin wheel arrangements on both half-axles 15, 15', the design of the axle arrangement 11 makes it possible to drive it either directly or to use it in towing operation, without having to change the central transmission components and the Engine may be stressed by excessive speeds.

The 4 The schematically illustrated embodiment largely corresponds to the one in 1 illustrated embodiment. The essential difference, however, is that the respective coupling 31, 31' of the two half-axles 15, 15' in this embodiment is not provided between the differential gear 19 and the respective reduction gear 33, 33', but on the wheel side of the respective reduction gear 33, 33', which has lower speeds but higher torques. Even with such an arrangement, the respective wheel hub 61, 61' can be selectively connected to or separated from the respective output 23, 23' of the differential gear 19 by means of the respective coupling 31, 31'. The separation, however, takes place between the respective wheel hub 61, 61' and the respective reduction gear 33, 33'. Due to the higher torques there, the respective coupling 31, 31' cannot be dimensioned as lightly as in the embodiments of the 1 to 3 However, the design of the 4 the advantage that in towing operation, a rotation of the respective wheel hub 61, 61' when the clutch 31, 31' is open is not transmitted to the respective reduction gear 33, 33' at all, so that drag losses at the reduction gear 33, 33' can be avoided.

At the 4 In the embodiment shown, the respective axle shaft 29, 29' for connecting the respective output 23, 23' of the differential gear 19 to the input element 35 of the respective reduction gear 33, 33' can also be formed integrally with the respective output 23, 23' and/or (as shown) with the input element 35, wherein at a free end of the axle shaft 29, 29' an indirect bearing can again be provided, optionally via the tooth engagement of a spline, in a hollow shaft section 25 or 37 of the respective output 23, 23' or of the input element 35.

In this embodiment, however, at least one respective output element 75, 75' must be provided between the output element 51 of the respective reduction gear 33, 33' and the respective wheel hub 61, 61', which is drivingly connected to the respective wheel hub 61, 61' and can be selectively connected to the output element 51 or separated therefrom by means of the respective clutch 31, 31'. This output element 75, 75' is in the embodiment of the 4 designed as an output shaft, which has a sliding sleeve 41 of the clutch 33, 33' arranged thereon in a rotationally fixed manner, which can be selectively brought (e.g., via a switching device 55, 55' (not shown) as described above) into engagement with a gear 43 of the clutch 33, 33', which is rotationally fixedly connected to the output element 51 or formed thereon. However, the sliding sleeve 41 can also be provided on the output element 51 and the gear on the output shaft 75, 75'.

For supporting the output shaft 75, 75', one end of it can be received in a hollow shaft section 77 of the output element 51 and can be mounted at least radially in the hollow shaft section 77 via a further bearing device 79. For axial support, plain bearing thrust washers (not shown) can also be provided. In addition, the output shaft 75, 75' can also be supported against the housing 13 of the axle assembly 11 via yet another bearing device 81. The bearing devices 79, 81 are, in particular, roller bearings.

List of reference symbols

11

Axle arrangement

13

Housing

15, 15'

semi-axis

17

Motor interface

19

differential gear

21

Entrance

22

ring gear

23, 23'

Exit

24

differential bevel gear

25

Hollow shaft section

27

Storage device

29, 29'

axle shaft

31, 31'

coupling

33, 33'

Reduction gear

35

Input element

37

Hollow shaft section

39

additional storage device

41

Sliding sleeve

43

gear

45

Input speed sensor

47, 47'

Input speed sensor

49, 49'

Output speed sensor

51

Output element

53

Control device

55, 55'

switching device

57

ring gear

59

planetary gear

61, 61'

wheel hub

65

Actuator

67

transmission element

69

push rod

71

rocker arm

75, 75'

Output shaft

77

Hollow shaft section

79

additional storage device

81

additional storage device

Claims (21)

Use of a drivable axle assembly (11) having two half-axles (15, 15') for driving a respective wheel hub (61, 61') and a differential gear (19) provided between the half-axles (15, 15') for distributing a drive torque of an engine to the two half-axles (15, 15'), wherein the differential gear (19) has an input (21) for receiving the drive torque and two outputs (23, 23') for outputting the drive torque to a respective half-axle (15, 15'), wherein the half-axles (15, 15') have a respective clutch (31, 31') and a respective reduction gear (33, 33') with an input element (35) associated with the differential gear (19) and an output element (51) associated with the respective wheel hub (61, 61'), which has a rotational speed of the output element (51) relative to the input element (35), wherein the respective clutch (31, 31') is arranged such that the respective wheel hub (61, 61') can be selectively connected to or separated from the respective output (23, 23') of the differential gear (19) by means of the respective clutch (31, 31'), in a trailer having a plurality of axles and designed to be towed by a tractor. Use of a drivable axle arrangement according to Claim 1 , wherein the input element (35) of the respective reduction gear (33, 33') can be selectively connected to or separated from the respective output (23, 23') of the differential gear (19) in a driving manner by means of the respective clutch (31, 31'), and wherein the output element (51) of the respective reduction gear (33, 33') is connected or connectable to the respective wheel hub (61, 61') in a driving manner. Use of a drivable axle arrangement according to Claim 1 or 2 , wherein the respective reduction gear (33, 33') is designed as a planetary gear comprising a sun gear (35), a planet carrier (51) and a ring gear (57), wherein an arrangement of planet gears (59) is rotatably mounted on the planet carrier (51) and meshes with the sun gear (35) and the ring gear (57), wherein the ring gear (57) is designed to be stationary, wherein the sun gear (35) forms the said input element (35) of the respective reduction gear (33, 33') and wherein the planet carrier (51) forms the said output element (51) of the respective reduction gear (33, 33'). Use of a drivable axle assembly according to one of the preceding claims, wherein the half-axles (15, 15') further comprise a respective axle shaft (29, 29'), wherein the input element (35) of the respective reduction gear (33, 33') is or can be connected in a drivingly effective manner to the respective output (23, 23') of the differential gear (19) via the respective axle shaft (29, 29'). Use of a drivable axle arrangement according to Claim 4 , wherein the respective axle shaft (29, 29') is drivingly connected to the respective output (23, 23') of the differential gear (19), and wherein the respective axle shaft (29, 29') can be selectively drivingly connected to the input element (35) of the respective reduction gear (33, 33') by means of the respective clutch (31, 31'). Use of a drivable axle arrangement according to Claim 4 or 5 , wherein the respective output (23, 23') of the differential gear (19) has a hollow shaft section (25), and wherein the respective axle shaft (29, 29') is partially received in a rotationally fixed manner in the hollow shaft section (25) of the output (23, 23') of the differential gear (19). Use of a drivable axle arrangement according to Claim 6 , wherein the respective output (23, 23') of the differential gear (19) is mounted exclusively indirectly. Use of a drivable axle arrangement according to one of the Claims 4 until 7 , wherein the input element (35) of the respective reduction gear (33, 33') has a hollow shaft section (37), and wherein the respective axle shaft (29, 29') is partially in the hollow shaft section (37) of the input element ments (35) of the respective reduction gear (33, 33'). Use of a drivable axle arrangement according to Claim 8 , wherein the respective axle shaft (29, 29') is rotatably mounted in the hollow shaft section (37) of the input element (35) of the respective reduction gear (33, 33') via a bearing device (39). Use of a drivable axle arrangement according to one of the Claims 4 until 9 , wherein the respective axle shaft (29, 29') is mounted exclusively indirectly. Use of a drivable axle arrangement according to one of the preceding claims, wherein the respective coupling (31, 31') is designed as a positive-locking coupling. Use of a drivable axle arrangement according to one of the Claims 1 until 10 , wherein the respective coupling (31, 31') is designed as a non-positive coupling. Use of a drivable axle arrangement according to one of the preceding claims, wherein the respective clutch (31, 31') is assigned a respective switching device (55, 55') for switching the respective clutch (31, 31'). Use of a drivable axle arrangement according to Claim 13 , wherein the respective switching device (55, 55') has an actuator (65) and a transmission element (67) in order to transmit a switching stroke of the actuator (65) to the respective clutch (31, 31') by means of the transmission element (67), wherein the transmission element (67) has a first end assigned to the actuator (65) and a second end assigned to the respective clutch (31, 31'), and wherein the first end of the transmission element (67) is arranged closer to the differential gear (19) and/or radially further away from the axis of rotation of the axle arrangement (11) than the second end. Use of a drivable axle arrangement according to Claim 14 , wherein the transmission element (67) has a joint arrangement. Use of a drivable axle arrangement according to one of the Claims 13 until 15 , wherein the switching devices (55, 55') for switching the respective clutch (31, 31') of the two half-axles (15, 15') are designed to switch the clutches (31, 31') together. Use of a drivable axle arrangement according to one of the Claims 1 until 12 , wherein the two clutches (31, 31') are assigned a switching device for switching the two clutches (31, 31'), wherein the switching device has an actuator (65) common to both clutches (31, 31') and at least one respective transmission element (67) in order to transmit a switching stroke of the actuator (65) to the respective clutch (31, 31') by means of the respective transmission element (67), wherein the respective transmission element (67) has a first end assigned to the actuator (65) and a second end assigned to the respective clutch (31, 31'), and wherein the first end of the respective transmission element (67) is arranged closer to the differential gear (19) and/or radially further away from the axis of rotation of the axle arrangement (11) than the second end. Use of a drivable axle assembly according to one of the preceding claims, wherein an input speed sensor (45) is provided to detect an input speed of the input (21) of the differential gear (19), wherein a respective output speed sensor (49, 49') is provided on both half-axles (15, 15') to detect an output speed of the respective clutch (31, 31'), and wherein a control device (53) is assigned to the axle assembly (11), which is designed to engage the respective clutch (31, 31') only when the difference between the detected input speed of the input of the differential gear (19) and the detected output speed of the respective clutch (31, 31') is less than a threshold value. Use of a drivable axle arrangement according to one of the Claims 1 until 17 , wherein a respective input speed sensor (47, 47') is provided on both half-axles (15, 15') in order to detect an input speed of the respective clutch (31, 31'), wherein a respective output speed sensor (49, 49') is further provided on both half-axles (15, 15') in order to detect an output speed of the respective clutch (31, 31'), and wherein a control device (53) is assigned to the axle arrangement (11), which control device is designed to close the respective clutch (31, 31') only when the difference between the detected input speed of the respective clutch (31, 31') and the detected output speed of the respective clutch (31, 31') is less than a threshold value. Use of a drivable axle arrangement according to one of the preceding claims, wherein the axle arrangement (11) is designed as a pendulum axle arrangement and has a fastening device by means of which the axle arrangement (11) can be fastened in a pendulum-movable manner to a carrier device of a vehicle. Use of a drivable axle arrangement according to one of the preceding claims, wherein the axle arrangement (11) comprises the motor, wherein the motor is a hydraulic motor or an electric motor.