DE102022203744A1 - Switchable transmission as well as trailer axle and vehicle trailer with such a transmission - Google Patents

Abstract

The present invention comprises a switchable transmission, comprising a housing (13), a first planetary gear (101) with a sun gear (1), a first ring gear (3) and at least one first planetary gear (4), and a second planetary gear (102). a second ring gear (5) and at least one second planetary gear (7), the second planetary gear (102) in particular not having a sun gear; wherein the first ring gear (3) and the second ring gear (5) are freely rotatable in the housing (13); a planet carrier (6); wherein the first planet gear (4) and the second planet gear (7) are connected to one another in a rotationally fixed manner and are rotatably mounted on or in the planet carrier (6); a clutch (K), which is provided between the first ring gear (3) and the planet carrier (6), the clutch (K) being designed to hold the first ring gear (3) or the planet carrier (6) in a rotationally fixed manner in order to do this switchable transmission to switch between a first gear position in which the second ring gear (5) of the second planetary gear forms the transmission input and the sun gear (1) forms the transmission output and a second gear position in which the sun gear (1) forms the transmission input and the second Ring gear (5) forms the transmission output.

Description

State of the art

The present invention relates to a switchable transmission, a trailer axle with such a switchable transmission and a vehicle trailer, in particular a caravan trailer or a truck trailer or a car trailer or the like with such a vehicle axle.

Vehicle trailers, e.g. caravans or truck trailers or the like, are moved using tractors. After arriving at a destination, it is often necessary to maneuver to the final destination (e.g. a loading ramp or a parking space for a caravan trailer). Maneuvering the tractor is difficult, especially when reversing, and is sometimes not possible due to a lack of space. Such trailers are then often uncoupled from the tractor for maneuvering and moved by hand, which requires a lot of effort. Or they are moved using a shunting drive, which drives the trailer's wheels directly via a movable drive roller on the trailer's tire. Such a maneuvering drive is usually provided on each tire of the trailer. In caravans, drive energy from such a maneuvering drive is taken, for example from a 12V on-board battery of the caravan.

For example, the shows EP 1 225 090 A2 such a maneuvering drive.

Disclosure of the invention

The switchable transmission according to the invention with the features of claim 1 has the advantage that the switchable transmission is not only designed for electrical maneuvering operation, but also offers operation of an electric machine as a generator, for example as a charging option for an energy storage device and/or as thrust support or serves to reduce the trailer mass to be towed by the towing vehicle. The switchable transmission of the invention has a particularly simple and robust structure and requires only a few movable components and a particularly small installation space. It can therefore be easily arranged on or in a trailer axle, for example in the immediate vicinity of a wheel connected to the trailer axle. Furthermore, a very high spread in the ratios of the individual gears can be provided by means of the switchable gearbox, for example a first gear ratio (of a first gear stage or first gear position) can be in a range from 1:1 to 14:1 (only the second planetary gear is active) and/or a second gear ratio (of a second gear stage or second gear position) can have a second gear ratio in a range from 30:1 to 450:1, preferably e.g. 50:1 to 350:1 (both planetary gears are active) . When used on a vehicle axle, the switchable transmission also enables a reduction in wear on the wheels on the vehicle axle, since the drive rollers of the prior art that roll on the wheels can be dispensed with. In particular, the switchable transmission also enables recuperation operation in addition to maneuvering operation. During a journey, if the switchable transmission is arranged on or in a trailer axle, for example, it can charge an energy storage device or supply electrical consumers in the trailer directly with electrical energy. In this case, the load on the towing vehicle's electrical system is advantageously relieved or is no longer needed at all to supply this consumer.

This is achieved according to the invention in that the switchable transmission has a housing and a first planetary gear and a second planetary gear. The first planetary gear includes a (first) sun gear, a first ring gear and at least one first planetary gear. The second planetary gear includes a second ring gear and at least one second planetary gear. The first ring gear and the second ring gear are freely rotatable in the housing of the shiftable transmission. The (first) sun gear of the first planetary gear is preferably connected to an input shaft (first shaft). An output shaft (second shaft) is preferably connected to the second ring gear. The transmission also has a planetary carrier (which can also be referred to as a planetary gear carrier). The first planet gear and the second planet gear are connected to one another in a rotationally fixed manner and are rotatably mounted on or in the planet carrier.

• ▪ einer ersten Gangstellung, in welcher das zweite Hohlrad des zweiten Planetengetriebes bzw. die mit dem zweiten Hohlrad verbundene zweite Welle den Getriebeeingang bildet und das Sonnenrad bzw. die mit dem Sonnenrad verbundene erste Welle den Getriebeausgang bildet, und
• ▪ einer zweiten Gangstellung, in welcher das Sonnenrad bzw. die mit dem Sonnenrad verbundene erste Welle den Getriebeeingang bildet und das zweite Hohlrad bzw. die mit dem zweiten Hohlrad verbundene zweite Welle den Getriebeausgang bildet.

Furthermore, a clutch is provided, which is arranged between the first ring gear and the planet carrier. The clutch is set up to hold the first ring gear or the planet carrier in a rotationally fixed manner. The clutch is set up to switch between the switchable transmission

• ▪ a first gear position in which the second ring gear of the second planetary gear or the second shaft connected to the second ring gear forms the transmission input and the sun gear or the first shaft connected to the sun gear forms the transmission output, and
• ▪ a second gear position in which the sun gear or the first shaft connected to the sun gear forms the transmission input and the second ring gear or the second shaft connected to the second ring gear forms the transmission output.

As a result, a very large spread in the gear ratios of the switchable transmission can be achieved with a single transmission and a single clutch, so that an electric drive or an electric machine can be used as a generator (e.g. during a cross-country journey) or as a drive (e.g. for a trailer to crawl ) can be used.

The clutch switching process is preferably carried out by means of a control unit or by means of an actuator that can be controlled by a control unit.

For example, it can be provided that in the second gear position the clutch couples the first ring gear to the housing in a rotationally fixed manner. The clutch thus enables the first ring gear to either rotate relative to the housing or for the first ring gear to be held in place relative to the housing. If the first ring gear can rotate, it rotates in the opposite direction to the direction of rotation of the (first) sun gear and the first planet gear also rotates in the opposite direction to the direction of rotation of the (first) sun gear.

Furthermore, it can be provided, for example, that in the first gear position the clutch couples the planet carrier to the housing in a rotationally fixed manner. The clutch thus allows the planet carrier to either rotate relative to the housing or for the planet carrier to be held in place relative to the housing. If the planet carrier can rotate, it rotates in the same direction of rotation as the (first) sun gear and the first planet gear rotates in the opposite direction to the direction of rotation of the (first) sun gear.

The switchable transmission preferably has exactly one clutch which holds the first ring gear or the planet carrier depending on the position of the clutch. This results in a particularly cost-effective and compact structure. It goes without saying that, for example, a further clutch position can be provided in which neither the second ring gear nor the planet carrier are held, but both can rotate freely. Such a further clutch position can be provided, for example, between the first gear position and the second gear position of the clutch. It is further understood that a single clutch can also have several force-transmitting or torque-transmitting elements, in particular those that can be displaced between the gear positions, such as clutch claws.

For example, it can be provided that the second planetary gear does not have a sun gear. In other words: it then only consists of at least one second planet gear and the second ring gear. If a second sun gear were to be provided in the second planetary gear, it would be coupled exclusively to the at least one second planet gear. In the following text, when the term “sun gear” is used, it is always to be understood as the (first) sun gear of the first planetary gear, unless something else is expressly described.

Furthermore, for example, the transmission can have a control unit which is set up to control the clutch. However, this control unit can also be present separately. It can be provided, for example, in an external control device, for example a Vehicle Control Unit (VCU). It can then be connected to the transmission via signal lines and control lines for the clutches, for example.

In the context of this application, the term “coupling” is initially to be understood functionally. This means: the coupling can connect or release an element with another element. The clutch can therefore be implemented using a (single mechanical) part, for example, as long as it can produce the various switching states. However, it can also be provided, for example, that the clutch has a first sub-clutch and the second sub-clutch and is implemented by two separate, independent components.

More preferably, the switchable transmission is set up to be axially connected to a shaft of a wheel. This can be arranged, for example, on a trailer axle.

An axial direction extends along an axis, for example an axis XX (see 1 ). A radial direction extends perpendicular to the axial direction and a circumferential direction refers to the direction that circumscribes the axial direction.

The subclaims show preferred developments of the invention.

The coupling preferably comprises a link and a guide element guided in the link, in particular a pin, preferably a cylindrical pin. The guide element can, for example, be designed to be movable in the link between a first position in the link and a second position in the link, whereby the coupling process is carried out when changing from the first position to the second position and vice versa.

This provides a particularly simple, robust, low-maintenance and reliable adjustment of the clutch from the first gear position to the second gear position. Furthermore, the shape of the link (e.g. its length and/or pitch) can be used to specifically influence the force required to adjust the clutch, so that, for example, an adjustment can be carried out by hand or by a small actuator with only a low torque. Furthermore, this embodiment allows the clutch and thus also the transmission to be made particularly small.

For example, it can be provided that the guide element extends essentially parallel to the axial direction. This allows the clutch and/or the transmission to be particularly compact, and in particular the expansion of the clutch or the transmission in the radial direction can be limited.

For example, it can be provided that the link is arranged in a circular ring segment which revolves around the axial direction. As a result, the clutch or the transmission can be made particularly compact or small, and in particular the expansion of the clutch or the transmission in the radial direction can be limited.

The gate opening particularly preferably extends over a rotation angle in the range between 15° and 110° and most preferably between 20° and 60°. This means that particularly low switching forces can advantageously be achieved.

Furthermore, the link can advantageously have a changing distance or radius along its direction of extension, for example in relation to the input shaft (first wave) or output shaft (second wave). In other words: it can have a slope. As a result, a distance of the guide element from a starting point (e.g. the input shaft and/or the output shaft) can advantageously be changed in the radial direction.

It can also be advantageous in this way that the clutch is self-locking in both gear positions, i.e.: that the forces acting on the clutch elements do not lead to, for example, the set second gear position being left unintentionally or the set first gear position being left unintentionally . Spring loading of the clutch can therefore advantageously be dispensed with. Such a self-locking can - only for example - be realized in that the link has a holding area in defined sections, which correspond, for example, to the first gear position and / or the second gear position, over a defined extension area with, for example, an unchanged radius or distance with respect to a starting point , e.g. regarding the input shaft and/or the output shaft. In other words: in this holding area, a radial force acting on the guide element, for example, cannot lead to a transformation of this force into a circular movement or a lateral movement of the element having the link. For example, it can also be provided to provide a small recess in the holding area (a kind of hollow) into which the guide element slides down. It can be provided, for example, that the holding area is, for example, at least 1.5 times, preferably at least twice, the extent of the guide element along the direction of extension of the link, particularly preferably at least three times the extent of the guide element along the direction of extension of the link. It can also be provided that the link has only a single holding area in which, for example, the radius of the link is constant over a defined extension area.

It goes without saying that the coupling can have exactly a single guide element and exactly a single link. However, several guide elements and/or several scenes can also be provided.

Further preferably, the guide element, in particular the pin, is firmly connected to a coupling claw. The guide element is set up to move the clutch claw between a first position for the first gear position in engagement with the planet carrier and a second position for the second gear position in engagement with the first ring gear. The design of the coupling with a link and guide element enables a particularly cost-effective, compact, low-maintenance and simple structure.

The advantage of using a clutch claw is that the transferable torque is increased thanks to the positive connection - this prevents the clutch from slipping. This makes shunting operations easier.

The connection of the guide element and the coupling claw advantageously enables the coupling claw to be displaced in a simple manner by moving the guide element in the link. If, for example, the link is displaced along the circumferential direction, the guide element follows the link and can be displaced, for example, along the radial direction, depending on the shape of the link.

It goes without saying that exactly one coupling claw can be provided. However, several coupling claws can also be provided, which are in particular spaced apart from one another. Each coupling claw can be firmly connected to a guide element.

In order to enable secure engagement of the clutch, the clutch claw preferably has internal teeth on an inside and external teeth on an outside. The internal toothing and the external toothing each engage with corresponding toothing in the planet carrier or the first ring gear.

The term internal toothing can refer to teeth that, viewed along the radial direction, are arranged further inwards (i.e. closer to the axis or shaft) than the teeth of the external toothing.

Further preferably, the coupling claw is set up in such a way that it can be moved exclusively in the radial direction (i.e. perpendicular to the axial direction) by means of the link and the guide element. This makes it advantageously possible for the clutch to have a very small installation space, particularly in the axial direction, since the clutch can be designed in the shape of a disc and the clutch process is only carried out in the radial direction.

The coupling claw is preferably held in a claw carrier, which is firmly connected to the housing. This makes it easy to hold the first ring gear or the planet carrier (depending on the gear position).

A particularly compact structure is possible if the link is formed in a shift drum, the shift drum being arranged rotatably in the circumferential direction (circumferential to the axial direction). Thus, by rotating the shift drum around the axial direction (in the circumferential direction), the link can be moved and thereby the guide element located in the link can be moved accordingly in the radial direction.

The shift drum is preferably switched manually or using an electric drive.

In order to further reduce the installation space of the shiftable transmission, the sun gear and/or the first and/or second ring gear are preferably mounted in the housing.

More preferably, an input shaft and an output shaft are arranged on a common axis.

This axis is initially to be understood as a virtual axis. It can, for example, be an axis of symmetry of the gearbox or its housing.

This advantageously results in a particularly compact design. Another advantage is that the risk of imbalance is reduced and the housing is subjected to fewer forces, especially in the radial direction. This in turn enables, for example, a smaller wall thickness of the housing and thus material and cost savings.

The common axis can run parallel to the axial direction A, for example.

In a further development it is provided that the first planetary gear and the second planetary gear are formed in one piece. This advantageously ensures that the ensemble of the two planetary gears is particularly cost-effective and easy to produce and that the transmission can therefore be designed to be particularly compact in the axial direction. This ensemble can, for example, be formed from the two planet gears as a monoblock without axial spacing from one another.

Alternatively, it can be provided that the first planetary gear and the second planetary gear and the first planetary gear axle are formed in one piece. This advantageously allows this ensemble of the two planetary gears and the planetary gear axle (which is also a shaft) to be manufactured particularly cost-effectively and easily. This also advantageously prevents the planetary gears that are to be mounted on the planetary gear axle from being mixed up. Finally, the axial geometry of the transmission can be advantageously adapted to design requirements using the length of the planetary gear axle.

It goes without saying that the transmission can have exactly one first planetary gear. However, it is also possible for several first planet gears to be provided, for example two, three, four, five or even more first planet gears.

It goes without saying that the transmission can have exactly one second planetary gear. However, it is also possible for several second planet gears to be provided, for example two, three, four, five or even more second planet gears. The number of second planet gears can preferably be equal to the number of first planet gears.

More preferably, the switchable transmission is set up to be axially connected to a shaft of a wheel. This can be arranged, for example, on a trailer axle.

Preferably, the number of teeth of the first ring gear and the second ring gear are different, so they differ by at least one tooth. The following applies: the smaller the difference in the number of teeth, the higher the gear ratio can be (depending on the switching status of the clutch).

For example, a number of teeth of the first planetary gear and the second planetary gear are the same. If in this case the number of teeth on the first ring gear and the second ring gear are different, a profile shift on the first ring gear, on the second ring gear or on both ring gears may be necessary due to a difference in center distance.

For example, a number of teeth of the first planetary gear and the second planetary gear are different.

The two alternative ensembles can be produced, for example, in a casting process or an injection molding process.

If a number of teeth on the first ring gear and a number of teeth on the second ring gear differ, a reversal of direction of rotation (input shaft to output shaft) can be effected depending on which of the two ring gears has more teeth.

The ratio of the number of teeth of the first ring gear (Z3) to the number of teeth of the second ring gear (Z5) can be, for example, in the range from 1:1.01 to 1:1.5, preferably in the range of at least 1:1.012 to 1:1.08. For example, the number of teeth of the first ring gear can be 60 and that of the second ring gear 57 or the number of teeth of the first ring gear can be 74 and that of the second ring gear 72. It goes without saying that the number of teeth can also be exactly the opposite (e.g. Z3 = 57 and Z5 = 60) if the direction of rotation of the output shaft is to be reversed compared to the first example. The ratio therefore always refers to the ratio of the larger number of teeth to the smaller number of teeth of the two ring gears.

This transmission topology makes it possible, for example, for a trailer axle to be operated in a shunting operation and, on the other hand, this transmission topology enables electric motor driving and/or generator operation when an electric machine is arranged on the input shaft. For example, during a normal towing journey of the trailer when attached to a tractor, an electric machine connected to the input shaft (first Shaft) is arranged, operated as an electric motor and provides additional support to the tractor. In generator operation, the electric machine can then, for example, charge an energy storage device that is installed on the vehicle trailer or directly supply electrical consumers that are located in the vehicle trailer, for example a refrigerator or a cooling unit or the like, with electrical energy.

Since the switchable transmission has two planetary gears arranged (directly) one behind the other, a small installation space can be realized for the switchable transmission. The gear designed in this way is advantageously particularly easily protected against the ingress of dirt or contaminants. Furthermore, the manufacturing costs for the switchable transmission can also advantageously be very low, especially when installed in or on a trailer axle. Depending on the desired operation of an electrical machine connected to the switchable transmission, a drive mode can be implemented in which the electrical machine is operated as an electric motor (drive motor) or a recuperation mode can be implemented in which the electrical machine is operated as a generator. In the drive mode, i.e. when the electric machine is operated as an electric motor (drive motor), a maneuvering gear and also a drive gear, in which the electric machine supports a tractor, can be set using the switchable transmission.

With a first gear stage (or a first gear position) in shunting mode, relatively small distances are usually covered, for example a few meters, e.g. less than 500 m or less than 100 m or even just less than 20 m. The speed in shunting mode is preferably low, e.g. less than 10 km/h, preferably less than 6 km/h, particularly preferably less than 3 km/h, more preferably less than 1 km/h. During maneuvering, a relatively high torque can be requested on a wheel driven by a trailer axle.

A second gear stage (or second gear position) can be used, for example, when driving, for example in a train operation, in which larger distances, for example more than 10 km or more than 100 km or more than 500 km, are covered. When towing, higher speeds are often reached, e.g. more than 70 km/h, which means that the wheel of a trailer axle rotates correspondingly quickly and this speed has to be absorbed in the switchable transmission.

It should be noted that to describe the invention, the input shaft (first shaft) of the shiftable transmission is always the shaft which is in connection with the electric machine and the output shaft (second shaft) of the shiftable transmission is always the shaft which is in communication with a wheel of a trailer or the like. It is self-evident to a person skilled in the art that when the electrical machine is switched from use in generator operation to motor operation (electric motor), the power flow in the system is reversed. In principle, the previous output shaft of the transmission becomes the input shaft and vice versa. Nevertheless, in order to avoid ambiguities in the description, the designations “input shaft” and “output shaft” are retained regardless of the operating mode of the electrical machine (i.e. reference is always made to a power flow in motor operation - the designations must therefore be swapped in generator operation) .

In the context of this application, the terms “comprising”, “comprise” are used synonymously with the terms “comprising”, “having”, unless otherwise described.

In motor operation, the input shaft could also be referred to as the drive shaft and the output shaft as the output shaft.

In a further development it is provided that the first planetary gear and the second planetary gear have a common planetary gear axle, with the first planetary gear and the second planetary gear being non-rotatably connected to the planetary gear axle, with the planetary gear axle being rotatably mounted in the planet carrier.

This advantageously makes it possible to implement a particularly simple structure, particularly if the first planetary gear and the second planetary gear have different numbers of teeth. Then, for example, the first planetary gear and the second planetary gear can advantageously be manufactured separately from one another and finally connected to the planetary gear axle. This also makes it easy to replace one of the planet gears, for example if a different gear ratio is to be produced. In this context, the planetary gear axis is not only to be understood as a virtual axis, but also as a (planetary gear) shaft.

Alternatively or additionally, it can be provided, for example, that the first planetary gear and the second planetary gear are not connected to one another via an axle, but rather are coupled directly to one another. In this case, for example, they can each have a coupling element on their axially outward-facing end face, with which they are mounted on or in the planet carrier. The coupling element can be, for example, a pin. Alternatively, it can also be provided, for example, that the two planet gears are made in one piece and have a hole or something similar in their center. An axle, for example, can then be guided through this hole. This axis can, for example, be non-rotatably connected to the planet carrier and belong to it. The two planet gears thus rotate around the axis belonging to the planet carrier.

It is preferably provided that the output shaft is mounted in the housing.

For this purpose, the output shaft can be mounted, for example, in a cover or a bottom of the housing. For example, the housing can be designed with a first bearing and/or with a second bearing. First and/or second bearings can be provided, for example, in the base and/or in the cover of the housing. The cover and/or the base can, for example, have a cylindrical bearing area in which one or more bearings for the output shaft are arranged.

This advantageously results in radial stabilization of the output shaft and a reduction in friction, thus improving the efficiency of the transmission.

Furthermore, a particularly simple and secure sealing of the interior of the housing of the transmission against fluid media, dirt and contaminants can be achieved, whereby the service life of the transmission can be increased.

Furthermore, a particularly compact structure with low weight can be achieved.

It can also be provided that the input shaft passes through the bottom (or the cover) of the housing (if the output shaft is passed through the cover (or the bottom)). The input shaft can preferably also be mounted on the housing base. This also ensures smoother running, radial stabilization of the input shaft and sealing of the interior of the housing.

More preferably, the output shaft (second shaft) is formed in one piece with the second ring gear. This enables a particularly simple and cost-effective structure.

In a further embodiment it is provided that a bearing is provided or arranged between an outer circumference of the first ring gear and the housing.

Alternatively or additionally, it is provided that a further bearing is provided or arranged between an outer circumference of the second ring gear and the housing.

As a result, great stability of the switchable transmission, especially in the radial direction, can be achieved and the first and second ring gear can still run freely relative to the housing if the clutches are switched accordingly. Furthermore, it is advantageous to achieve particularly low friction between the respective outer circumference of the mounted ring gear and the housing, thereby improving the efficiency of the transmission.

The bearings can be designed, for example, as plain bearings, as ball bearings, as rolling bearings or as needle bearings.

More preferably, the switchable transmission comprises at least one belt drive. The belt drive is preferably arranged on the input shaft and connects the input shaft in particular to an electrical machine. Alternatively, a belt drive is additionally or solely arranged on the output shaft. The belt drive on the output shaft can, for example, connect or couple the output shaft to a shaft or axle of a wheel of a vehicle, in particular a vehicle trailer.

The belt drive can advantageously prevent overloading of the switchable transmission due to excessive torque loads. If the torque is too high, the belt drive can slip like a predetermined breaking point and thus relieve the load on the switchable transmission.

The belt drive can also advantageously be designed as a belt transmission, whereby a further transmission stage can be provided in addition to the two gears of the switchable transmission. A translation can - just as an example - be in a range from 1:1.2 to 1:4. Other translations or reductions are also conceivable.

The present invention further relates to a trailer axle with a switchable transmission according to the invention and with an electrical machine which is set up to be operated as an electric motor or as a generator.

Such a trailer axle can - just for example - be a rigid connecting element (e.g. a hollow beam) between a left and right side of a trailer, at the free ends of which wheels can preferably be arranged directly or indirectly. The trailer axle can also have, for example, a spring element at each of its ends, to which a wheel or rim of the trailer can be attached. For example, such a spring element can be designed as a leaf spring or as a rocker arm, which is provided, for example, with a torsion spring. Such a swing arm can, for example, be sprung on the trailer axle.

Generally speaking, a suspension (e.g. designed as a torsion bar) can be arranged between the trailer axle and a trailer chassis.

It goes without saying that the trailer axle can have such a switchable gearbox on each side (left/right viewed with respect to the direction of travel). Each shiftable transmission can have its own motor on the input shaft. However, it is also possible for only a single electric machine to be provided, which is connected to the input shafts of two or more switchable transmissions.

Further preferably, an energy storage device is provided, which is (electrically) connected to the electrical machine. The energy storage device is set up to supply the electrical machine with electrical energy when it is operated as an electric motor and to store electrical energy when the electrical machine is operated as a generator.

The present invention further relates to a vehicle trailer with a trailer axle according to the invention. The vehicle trailer is, for example, a caravan or a trailer of a truck or another trailer of a car.

Particularly preferably, the vehicle trailer comprises at least one electrical consumer that is electrically connected to the electrical machine, in particular a refrigerator, an air conditioning system, a television, a hot water heater, a microwave, a hair dryer or a refrigeration unit (e.g. for refrigerated trailers of a truck). The electrical consumer can be supplied with electrical energy directly from the electrical machine in generator mode or via one or more electrical (additional) energy storage devices.

An electrical connection between the electrical machine and the electrical consumers can take place indirectly, for example via an energy storage device and/or via an on-board electrical system of the vehicle trailer, or directly.

It can be provided that an additional energy storage unit of the vehicle trailer is connected to the electrical machine. As a result, this additional energy storage can advantageously be charged in generator operation or, in maneuvering operation, the vehicle trailer can take the energy required for maneuvering directly from the additional energy storage. An (electrical) connection to the towing vehicle or an external connection (e.g. a socket) is then advantageously no longer necessary - the vehicle trailer is advantageously autonomous in terms of energy.

For example, a voltage converter can be arranged between the energy storage and the electrical trailer electrical system, which makes it possible to operate the energy storage with a voltage level that is different from the trailer electrical system.

Short description of the drawing

• 1 eine schematische Darstellung eines schaltbaren Getriebes für eine Fahrzeugachse eines Fahrzeuganhängers gemäß einem bevorzugten Ausführungsbeispiel der Erfindung in einer ersten Gangstellung,
• 2 eine schematische Schnittansicht entlang der Linie B-B von 1,
• 3 eine schematische Schnittansicht entlang der Linie C-C von 1,
• 4 eine schematische Darstellung eines schaltbaren Getriebes für eine Fahrzeugachse eines Fahrzeuganhängers gemäß einem bevorzugten Ausführungsbeispiel der Erfindung in einer zweiten Gangstellung,
• 5 eine schematische Schnittansicht entlang der Linie E-E von 4, und
• 6 eine schematische Schnittansicht entlang der Linie F-F von 4.

A preferred embodiment of the invention is described in detail below with reference to the accompanying drawing. In the drawing is:

• 1 a schematic representation of a switchable transmission for a vehicle axle of a vehicle trailer according to a preferred embodiment of the invention in a first gear position,
• 2 a schematic sectional view along line BB of 1 ,
• 3 a schematic sectional view along line CC from 1 ,
• 4 a schematic representation of a switchable transmission for a vehicle axle of a vehicle trailer according to a preferred embodiment of the invention in a second gear position,
• 5 a schematic sectional view along line EE from 4 , and
• 6 a schematic sectional view along line FF of 4 .

Preferred embodiment of the invention

Below is with reference to the 1 until 6 a switchable transmission 100 according to a preferred embodiment of the invention is described in detail. The switchable transmission 100 is here - merely by way of example - arranged in or on a trailer axle of a vehicle trailer, with only a shaft 20 being shown here, which can be connected, for example, to a wheel which can be attached to the trailer axle.

1 shows that the switchable transmission 100 is arranged between the shaft 20 and an electric machine 21. The electric machine 21 is connected to a control unit 22, which also controls or switches the switchable transmission 100. Furthermore, the electric machine 21 is connected to an energy storage device 23, for example a battery of a trailer electrical system, which can be operated, for example, with 12V, 24V, 36V, 48V, etc.

1 shows schematically the switchable transmission 100 in a longitudinal section. The switchable transmission 100 includes a first planetary gear 101 and a second planetary gear 102 as well as a planet carrier 6. As shown 1 As can be seen, the two planetary gears 101, 102 are arranged one after the other, here viewed along an axis XX in a row one after the other or one behind the other. The axis XX can represent an axial direction A. A radial direction or radial direction R runs perpendicular to the axial direction A. A circumferential direction U runs around the axial direction A.

The first planetary gear 101 includes a (first) sun gear 1 (hereinafter simply referred to as “sun gear”), first planetary gears 4, and a first ring gear 3.

The transmission shown here has, for example, three first planet gears 4, each offset by 120° from one another.

The (first) sun gear 1 has a first toothing Z1, the first planet gears 4 have second toothings Z2 and the first ring gear 3 has a third toothing Z3. In the cross section shown, the three first planetary gears 4 can be seen: in the upper half, two first planetary gears 4 can be seen in top view (one of which is partially covered by the (first sun gear 1) and in the lower half another first planetary gear 4 is cut. It However, it is also possible that only a single first planetary gear 4 is present or that more than two first planetary gears 4 are provided, for example three, four, five, six or even more first planetary gears 4.

The second planetary gear 102 here includes, for example, three second planetary gears 7, which are each offset by 120° from one another, and a second ring gear 5. The second planetary gears 7 have a fourth toothing Z4 and the second ring gear 5 has a fifth toothing Z5. In the cross section shown, the three second planet gears 7 can be seen (here too: in the upper half of 1 two second planet gears 7 in top view and a second planet gear 7 cut in the lower half). However, it is also possible that only a single second planetary gear 7 is present or that more than two second planetary gears 7 are provided, for example three, four, five, six or even more second planetary gears 7.

The second planetary gear 102 does not have a sun gear here. The first planetary gears 4 are here - merely as an example - each attached to planetary gear axles 18 (or planetary gear shafts). The planet gear axles 18 are mounted in or on the planet carrier 6, in particular rotatably mounted, with - here only as an example - the first and second planet gears 4, 7 being arranged within the planet carrier 6.

The first ring gear 3 and the second ring gear 5 are freely rotatable in a two-part housing 13, 13 '.

The (first) sun gear 1 is connected to an input shaft 10 (first shaft) or is arranged or formed on the input shaft 10.

How further from the 1 As can be seen, the input shaft 10 (first shaft) and an output shaft 11 (second shaft) are arranged on the (here: common) axis XX.

The transmission 100 also has the planet carrier 6, wherein the first planet gears 4 and the second planet gears 7 are connected to one another in a rotationally fixed manner and are rotatably mounted on the planet carrier 6. In this exemplary embodiment, the first planetary gears 4 and the second planetary gears 7 are each coupled or connected to one another in a rotationally fixed manner by the common planetary gear axle 18. First planetary gear 4, second planetary gear 7 and planetary gear axle 18 can be formed in one piece, for example as a cast part or injection molded part. The planet wheel axle 18 is rotatably mounted in the planet carrier 6. The planet carrier 6 is here - for example only - arranged between first planetary gears 4 and second planetary gears 7, viewed along the axial direction A. This arrangement is not essential for the function of the transmission 100.

The housing 13, 13' encloses the switchable transmission 100 and has a through opening 24 on a bottom of the housing 13, 13'. The input shaft 10 is passed through the through opening 24. It is also stored here, for example, on a bearing 31.

The housing 13, 13 'has a flange region 113, which is here, for example, cylindrical, in particular circular cylindrical. A first bearing 111 and a second bearing 112 are arranged in the flange area, which support the second ring gear 5, to which the output shaft 11 (second shaft) is connected. The output shaft 11 (second shaft) is guided here, for example, through a cover of the housing 13, 13`.

In principle, the output shaft 11 could also be guided through the bottom of the housing 13, 13' and the input shaft 10 through the cover.

The second ring gear 5 is also arranged or attached to the output shaft 11.

The first planetary gear 101 and the second planetary gear 102 are basically arranged to rotate freely inside the housing 13, 13'. Here, the first ring gear 3 is supported by bearings not specified here. The bearings can be designed, for example, as a plain bearing or a rolling element bearing, for example a needle bearing or a ball bearing.

Depending on the operating mode of the transmission, the sun gear 1 takes on the task of either the output (gear position 1) or the drive (gear position 2). The exemplary embodiment shown includes a fixed connection 2, which firmly connects the planet gears 4, 7 of the two planetary gears 101, 102 to one another. On the planet carrier 6, receptacles 17 are arranged concentrically to the axis of rotation of the sun gear. These receptacles 17 are each coaxial with one another on both the left and right sides of the planet carrier 6.

The planetary gear axle 18 is pressed into the two receptacles 17 in the form of a bearing pin. On the planetary gear axle 18, the first and second planetary gears 4, 7 are mounted here, for example, via a plain bearing or a rolling bearing.

The planet carrier 6 is mounted concentrically to the axis of rotation in the housing 13 and on the output side of the transmission indirectly via the second ring gear 5 in the housing 13. Depending on the gear position, the planet carrier 6 either supports the transmission torque (gear position 2) or rotates freely (gear position 1).

For this purpose, the switchable transmission 100 has exactly one clutch K. The clutch K is arranged on an end face of the transmission 100 and has a substantially disk-shaped design. This allows a very compact structure to be achieved.

The 1 until 3 show the clutch K in detail. The clutch K here only includes, by way of example, three clutch claws 8, which can only be moved radially (along the radial direction R).

It goes without saying that instead of a claw clutch, it is also possible to design it as a friction clutch.

2 shows that each clutch claw 8 (here: on the outer circumference) has an external toothing K1 and (here: on the inner circumference) has an internal toothing K2. The first ring gear 3 has clutch teeth K3 on the inner circumference. The planet carrier 6 has clutch teeth K4 on a ring gear 61. The ring gear 61 is fixed to the planet carrier 6 by means of a press fit, for example.

By moving the clutch claw 8 radially, the clutch claw 8 comes either with the clutch teeth K4 of the planet carrier 6 ( 2 ) or with the clutch teeth K3 of the ring gear 3 ( 5 ) engaged.

The 1 until 3 show the first gear position of the recuperation mode, in which the transmission 100 has a large gear ratio. This allows the electrical machine 21 to be operated as a generator.

The 4 until 6 show the second gear position, in which a small translation, for example for shunting, is provided. Here, the electrical machine 21 can be operated by a motor, for example.

In addition to the clutch claws 8, the clutch K also includes a link S1 for each clutch claw and a guide element 15 guided in the link S1, for example a pin. Each guide element 15 is firmly connected to a coupling claw 8.

The 3 and 6 show the shape of the backdrop S1. The shape of the link S1 is chosen such that a radial position of the guide element 15 (here: the pin) is changed when it moves in the circumferential direction U. As in 3 shown, in the inner radial position the guide element 15 (here: the pin) is arranged at the first end of the link S1. The clutch claws 8 are in engagement with the planet carrier 6 and out of engagement with the first ring gear 3. In the position of the second gear position in 6 the guide element 15 (here: the pin) is located at the opposite end of the link S1 and the clutch claws 8 are in engagement with the first ring gear 3 and out of engagement with the planet carrier 6.

It can be seen that the link S1 no longer has a slope at its respective ends, but corresponds to a circular segment (constant radius based on the input shaft 10 (first wave). This section can be referred to, for example, as a holding area or holding section. This is advantageous causes a self-locking mechanism, which prevents radial pressure on the clutch claws 8 from causing the guide element 15 to carry out a downward or upward movement in the link S1 and thus exerts a rotary movement on a shift drum 16 in which the link S1 is in this Embodiment is arranged as an example.

The exactly one clutch K can therefore be switched between two, in particular between exactly two, positions (engagement with the first ring gear 3 or engagement with the planet carrier 6). It can be provided that an idle is provided between the two switching positions, in which the shifting claws 8 are not in engagement with either the first ring gear 3 or the planet carrier 6. This switching position can, for example, be designed as a non-stable intermediate state. However, it could also be provided that the link S1 for this switching state also has a plateau with a constant radius over a certain angular range or a hollow or the like, i.e. a further holding area or holding section, which is, for example, at least 1.5 times preferred corresponds to at least twice and particularly preferably three times the angular circumference of the guide element 15 or the extension dimension of the guide element 15 along the extension direction of the link S1. For this purpose, for example, the backdrop could extend over an angular range of up to 110°.

The clutch claws 8 are arranged in a claw carrier 14. The clutch claws 8 are arranged in the claw carrier 14 in such a way that they can only move in the radial direction R. A movement of the coupling claws 8 in the axial direction A or tangential direction or circumferential direction U is not possible in this merely exemplary embodiment. The claw carrier 14 is firmly connected to the gear housing 13. Forces with which the clutch claws 8 support the first ring gear 3 or the planet carrier 6 can thus be transmitted to the housing 13 via the claw carrier 14.

The movement of the link S1 takes place here, for example, by means of a shift drum 16 (cf. 3 and 6 ). The shift drum 16 is designed in such a way that by rotating the shift drum 16 about the transmission center axis, the clutch claws 8 are brought into the desired end position for the first gear position or the second gear position via the guide elements 15.

The shift drum 16 can be adjusted by an electric motor, for example via an actuator or a spindle drive, or manually.

In detail, in the first gear position (generator operation of the electric machine), which in the 1 until 3 is shown, the clutch claws 8 in the inner position. Ie, the clutch teeth K2 of the clutch claws 8 are in engagement with the clutch teeth K4 of the ring gear 61 of the planet carrier 6. The planet carrier 6 is therefore no longer freely rotatable. The clutch teeth K1 of the clutch claws 8 are not in engagement with the clutch teeth K3 of the first ring gear 3. The first ring gear 3 can therefore rotate freely. The guide elements 15 are located at the radially innermost position of the first gear position (see 2 ).

In the first gear position, the drive into the transmission is preferably via the second ring gear 5 (in 1 from the left). The second ring gear 5 drives the second planetary gears 7 via the fifth toothing Z5, which meshes with the fourth toothing Z4 of the second planetary gears 7. The second toothing Z2 of the first planet gears 4, which are firmly connected to the second planetary gears 7, mesh with the third internal toothing Z3 of the first ring gear 3. Since the planet carrier 6 is stationary, since the clutch claws 8 hold the planet carrier 6 (cf. 2 ) and couple it to the housing 13, 13 'and the first ring gear 3 is freely rotatable, the first ring gear 3 rotates freely. The second toothing Z2 of the first planet gears 4 still mesh with the first toothing of the sun gear 1. As a result, the sun gear 1 (first toothing Z1) is driven and, in the first gear position, acts as a drive to drive the electric machine 21, which is therefore operated as a generator can be. It goes without saying that, in principle, the electric machine could also be operated by a motor in the first gear position, for example in order to relieve the load on a towing vehicle during a cross-country journey by driving a trailer equipped with the switchable transmission 100 itself.

wobei N1 die Zähnezahl des (ersten) Sonnenrads, N2 die Zähnezahl der ersten Planetenräder 4, N3 die Zähnezahl des ersten Hohlrads 3, N4 die Zähnezahl der zweiten Planetenräder 5 und N5 die Zähnezahl des zweiten Hohlrads 13 ist.The following applies to the translation in the first gear position: $$\text{i}1\left(\text{N}\mathrm{1,}\text{N}\mathrm{2,}\text{N}\mathrm{4,}\text{N}5\right)=\left(\text{N}2*\text{N}5\right)/\left(\text{N}1*\text{N}4\right),$$

where N1 is the number of teeth of the (first) sun gear, N2 is the number of teeth of the first planetary gears 4, N3 is the number of teeth of the first ring gear 3, N4 is the number of teeth of the second planetary gears 5 and N5 is the number of teeth of the second ring gear 13.

With the following numbers of teeth of N1 = 15, N2 = 22, N4 = 20, N5 = 57 (and N3 = 60), which are only to be understood as an example, the result is: $$\text{i}1=\left(22*57\right)/\left(15*20\right)=\mathrm{4.18.}$$

The 4 until 6 show the second gear position in which output takes place via the second ring gear 5. How out 5 As can be seen, the clutch claws 8 are in the outer position, with the clutch teeth K1 of the clutch claws 8 in engagement with the clutch teeth K3 of the first ring gear 3. The first ring gear 3 is therefore fixed and cannot be rotated. The clutch teeth K2 of the clutch claws 8 are no longer in engagement with the clutch teeth K4 of the planet carrier 6. The guide elements 15 are located at the outermost position in the link S1 (cf. 6 ). Here you can also clearly see the plateau or the holding area of the link S1, which prevents the shift roller 16 from being pushed towards the first gear position when a force acts on the guide element 15 in the radial direction R.

In the second gear position, the transmission 100 is driven via the sun gear 1. The sun gear 1 drives the second planetary gears 7 via the fixed connection via the first toothing Z1, which meshes with the second toothing Z2 of the first planetary gears 4. The second toothing Z2 of the first planet gears 4 also meshes with the third toothing Z3 of the ring gear 3. Since the planet carrier 6 is freely rotatable and the first ring gear 3 is stationary, the planet carrier 6 is set in rotation. The fourth toothing Z4 of the second planet gears 7 continues to mesh with the fifth toothing Z5 of the second ring gear 5, which is thereby driven. The second ring gear 5 thus functions as an output in the second gear position.

Furthermore, the switchable transmission includes the control unit 22, which is set up to control the clutch K (in 4 the electric machine 21, the control unit 22 and the energy storage 23 are not shown for reasons of clarity). For reasons of clarity, the corresponding control lines are included here 1 not shown. Furthermore, the control unit 22 can also control the electrical machine 21 as an electric motor or generator.

The switchable transmission 100 can thus be operated in two operating modes.

The fixed connection 2 between first planetary gears 4 and second planetary gears 7 causes the second planetary gears 7 to move at the same angular speed and in the same direction of rotation as the first planetary gears 4.

In the second gear position, the planet carrier 6 rotates in the same direction as the (first) sun gear 1.

• ▪ zum einen wird das zweite Hohlrad 5 mittels der Verzahnung zu den zweiten Planetenrädern 7 in eine Drehbewegung versetzt, die in dieselbe Drehrichtung gerichtet ist wie die Drehrichtung der zweiten Planetenräder 7 (also entgegen der Drehrichtung des (ersten) Sonnenrads 1);
• ▪ zum anderen wird das zweite Hohlrad 5 mittels der Verzahnung zum Planetenträger 6 in eine Drehbewegung versetzt, die in dieselbe Drehrichtung gerichtet ist wie die Drehrichtung des Planetenträgers 6 (also in dieselbe Drehrichtung des (ersten) Sonnenrads 1).

The movement of the second ring gear 5 is made up of two contributions:

• ▪ on the one hand, the second ring gear 5 is set into a rotational movement by means of the toothing to the second planet gears 7, which is directed in the same direction of rotation as the direction of rotation of the second planet gears 7 (i.e. opposite to the direction of rotation of the (first) sun gear 1);
• ▪ on the other hand, the second ring gear 5 is set into a rotational movement by means of the toothing to the planet carrier 6, which is directed in the same direction of rotation as the direction of rotation of the planet carrier 6 (i.e. in the same direction of rotation of the (first) sun gear 1).

Thus, the second ring gear 5 rotates at a rotational speed (angular velocity) and a direction of rotation that depends on how large the two components set out above are.

As a result, a very high gear ratio can be achieved, which is higher the more similar the rotational speeds (angular speeds) of the second planet gears 5 and the planet carrier 6 are.

For a gear ratio i2 in the second gear position: $$\text{i}2\left(\text{<figure-callout id="1" label="N" filenames="DE102022203744A1\_0005.png,DE102022203744A1\_0006.png" state="{{state}}">N</figure-callout>}\mathrm{1,}\text{<figure-callout id="2" label="N" filenames="DE102022203744A1\_0005.png,DE102022203744A1\_0007.png" state="{{state}}">N</figure-callout>}\mathrm{2,}\text{<figure-callout id="3" label="N" filenames="DE102022203744A1\_0005.png,DE102022203744A1\_0006.png" state="{{state}}">N</figure-callout>}\mathrm{3,}\text{<figure-callout id="4" label="N" filenames="DE102022203744A1\_0005.png,DE102022203744A1\_0007.png" state="{{state}}">N</figure-callout>}\mathrm{4,}\text{N}5\right)=\left(1+\text{<figure-callout id="3" label="N" filenames="DE102022203744A1\_0005.png,DE102022203744A1\_0006.png" state="{{state}}">N</figure-callout>}3/\text{N}1\right)/\left\{1-\left(\text{<figure-callout id="4" label="N" filenames="DE102022203744A1\_0005.png,DE102022203744A1\_0007.png" state="{{state}}">N</figure-callout>}4*\text{N}3\right)/\left(\text{<figure-callout id="2" label="N" filenames="DE102022203744A1\_0005.png,DE102022203744A1\_0007.png" state="{{state}}">N</figure-callout>}2*\text{N}5\right)\right\}.$$

With the following numbers of teeth of N1 = 15, N2 = 22, N3 = 60 as well as N4 = 20 and N5 = 57 (see also above for i1), which are only to be understood as an example: $$\text{i}2\left(\mathrm{15,22,60,20,57}\right)=116.11$$

Thus, by cleverly arranging two planetary gears 101, 102 in series, a high ratio spread can be achieved cost-effectively and in a very space-saving manner. This high ratio spread is necessary in order to enable maneuvering operation (low speed requirement, high torque requirement) and also recuperation operation (high available speed on the output shaft (second axis)) of the electric machine 21 or overrun operation during a cross-country journey. In particular, a desired high ratio spread can be achieved by simply switching the single clutch K.

The compactness of the switchable transmission is further enhanced by the fact that exactly one clutch is arranged in a disk shape on one end face of the transmission.

Thus, according to the invention, a trailer axle can also be provided (not shown here). In conjunction with an electric machine 21, which can work as an electric motor and as a generator, such a trailer axle can be used in a simple manner for maneuvering and, when the trailer is towing, enable the electric machine to operate as a generator at correspondingly high speeds. The necessary high ratio spread for the different requirements of the electric machine can be achieved by the switchable transmission 100.

The desired translation (if it is not already achieved by the transmission 100 alone) can also be achieved or adjusted by providing an additional belt drive or chain drive, which is designed as a belt drive or chain drive. For example, this belt drive or chain drive can be arranged on the input shaft (first shaft) or on the output shaft (second shaft) or be connected to it (directly or indirectly).

In addition, a predetermined breaking point or a slip clutch can be provided between the electric motor or the electric machine and the switchable transmission, which prevents the switchable transmission from being damaged by sudden or permanent torque.

In addition, a predetermined breaking point or a slip clutch can be provided between an element connected to the output shaft (e.g. a wheel attached to a trailer axle) and the switchable transmission, which prevents the switchable transmission from being damaged by sudden or permanent torque.

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 1225090 A2 [0003]

Claims (15)

Switchable transmission, comprising: - a housing (13), - a first planetary gear (101) with a sun gear (1), a first ring gear (3) and at least one first planetary gear (4), - wherein the sun gear (7) is connected to an input shaft (10); - a second planetary gear (102) with a second ring gear (5) and at least one second planetary gear (7), - wherein the second planetary gear (102) in particular does not have a sun gear; - wherein the first ring gear (3) and the second ring gear (5) are arranged freely rotatable in the housing (13); - wherein the second ring gear (13) is connected to an output shaft (11), - a planet carrier (6); - wherein the first planet gear (4) and the second planet gear (7) are connected to one another in a rotationally fixed manner and are rotatably mounted on or in the planet carrier (6); - a clutch (K), which is provided between the first ring gear (3) and the planet carrier (6), wherein the clutch (K) is set up to hold the first ring gear (3) or the planet carrier (6) in a rotationally fixed manner in order to switch the switchable transmission between - a first gear position, in which the second ring gear (5) of the second planetary gear forms the gear input and the sun gear (1) forms the gear output and in particular the clutch (K) couples the planet carrier (6) to the housing (13) in a rotationally fixed manner and - a second gear position, in which the sun gear (1) forms the transmission input and the second ring gear (5) forms the transmission output and in particular the clutch (K) couples the first ring gear (3) to the housing (13) in a rotationally fixed manner, in particular the Input shaft (10) and/or the output shaft (11) run parallel to an axial direction (A). Gearbox after Claim 1 , wherein the coupling (K) comprises a link (S1) and a guide element (15) guided in the link (S1), the guide element (15) extending in particular essentially parallel to the axial direction (A), the link ( S1) is arranged in particular in a circular ring segment which revolves around the axial direction (A). Gearbox after Claim 2 , wherein the guide element (15) is firmly connected to a clutch claw (8) and is set up to move the clutch claw (8) between - a first position (P1) for the first gear position in engagement with the planet carrier (6) and - a second position (P2) for the second gear position in engagement with the first ring gear (3). Gearbox after Claim 3 , wherein the clutch claw (8) has internal teeth (K2) on an inside and external teeth (K1) on an outside. Gearbox after Claim 3 or 4 , wherein the coupling claw (8) can be moved exclusively in a radial direction (R) perpendicular to the axial direction (A) by means of the link (S1) and the guide element (15). Gearbox according to one of the Claims 3 until 5 , further comprising a claw carrier (14) which is connected to the housing (13) and holds the clutch claw (8). Gearbox according to one of the Claims 2 until 6 , wherein the link (S1) is formed in a shift drum (16), wherein the shift drum (16) is rotatably arranged in a circumferential direction (U) surrounding the axial direction (A). Gearbox after Claim 7 , wherein the shift drum (16) can be switched manually or by means of an electric drive. Transmission according to one of the preceding claims, wherein the sun gear (1) and/or the first ring gear (3) and/or the second ring gear (5) is mounted in the housing (13). Transmission according to one of the preceding claims, wherein the input shaft (10) and the output shaft (11) are arranged on a common axis (XX), the axis (XX) in particular running parallel to the axial direction (A). Gearbox according to one of the preceding claims, wherein the first planetary gear (4) and the second planetary gear (7) are formed in one piece, or wherein the first planetary gear (4) and the second planetary gear (7) and a first planetary gear axle are formed in one piece. Trailer axle, comprising a switchable transmission (100) according to one of the preceding claims and an electrical machine (21), which is set up to be operated as an electric motor or as a generator. Trailer axle according to the preceding claim, further comprising an energy storage device (23) which is electrically connected to the electrical machine (21). Vehicle trailer, comprising a trailer axle according to one of the two preceding claims. Vehicle trailer according to the preceding claim, wherein an electrical consumer of the vehicle trailer is electrically connected to the electrical machine (21) of the trailer axle and/or wherein an additional energy storage (23) of the vehicle trailer is connected to the electrical machine (21).

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