Differential gear

Abstract

The disclosure relates to differential gears comprising a first gear set, a second gear set, an input element, a first output shaft, a second output shaft, a first switching element, and a second switching element. The first gear set is mechanically coupled to the second gear set. The input element is designed for connection to a drive unit and for transmitting torque to the first gear set. The first output shaft is designed for selectively receiving torque from the first gear set via a coupling element. The second output shaft is designed for receiving torque from the second gear set. The first switching element and the second switching element are displaceable between their respective locked and unlocked positions. The first output shaft is rotationally fixed to the second output shaft via the first switching element when it is in its locked position.The first output shaft is non-rotatably connected to the coupling element via the second switching element, which is in its locked position. The disclosure further relates to a vehicle with the differential gear.

Description

Technical field

[0001] The present disclosure relates to a differential gear and a vehicle with the differential gear. State of the art

[0002] Differential gears with differential locking devices for locking a vehicle's drive unit, thus enabling safe driving even on slippery surfaces, are known. Differential gears are also known that are capable of disengaging a drive unit coupled to the differential gear from the differential gear, particularly from its output shafts. Description of the invention

[0003] The present disclosure relates, in a first aspect, to a differential gear comprising a first gear set, a second gear set, an input element, a first output shaft, a second output shaft, a first switching element, and a second switching element. The first gear set is mechanically operatively connected to the second gear set. The differential gear can be configured as a gear with a ratio other than 1. For example, the differential gear can be configured as a reduction gear. The differential gear can be designed such that it can distribute a torque introduced via the input element to the first output shaft and the second output shaft. In addition, the differential gear can enable relative rotation of the first and second output shafts, thus providing a differential function.

[0004] If two elements are mechanically connected, they are coupled directly or indirectly, such that a movement of one element causes a reaction in the other. A mechanical connection can be established, for example, by friction or positive locking. The mechanical connection can correspond to the meshing of gears between corresponding gears of the two elements. Additional elements, such as one or more spur gear stages, can be present between the elements. A permanent, non-rotatable connection, on the other hand, is a connection in which the two elements are rigidly coupled. The elements can be designed as separate, non-rotatably connected components or as a single piece.

[0005] The input element is designed for connection to a drive unit. The drive unit can be an electric motor and / or an internal combustion engine. The input element is designed to transmit torque to the first wheelset. The first output shaft is designed to selectively receive torque from the first wheelset via a coupling element of the first wheelset. The coupling element can be arranged in a torque flow between the first wheelset and the first output shaft. The coupling element can connect an element of the first wheelset to the first output shaft in a rotationally fixed manner. The first output shaft can be designed to output torque to a first drive element of a vehicle. The second output shaft is designed to receive torque from the second wheelset. The second output shaft can be designed to output torque to a second drive element of the vehicle.The first driving element could be, for example, the left wheel and the second driving element the right wheel of the vehicle. The vehicle could be, for example, a passenger car, a bus, or a piece of construction equipment. In the case of construction equipment, it could be, for example, agricultural machinery, construction equipment, or a commercial vehicle. An example of agricultural machinery is a tractor. An example of construction equipment is a wheel loader. Examples of commercial vehicles are a municipal vehicle, a dump truck, and a concrete mixer truck.

[0006] The first switching element and the second switching element are each movable between a locked position and an unlocked position. Each switching element can be configured to create a rotationally fixed connection between two elements.

[0007] The switching element can have at least two switching positions. One switching position can be a locked position, in which the switching element is closed. In the locked position, a rotationally fixed connection can be established between two elements. Another switching position can be an unlocked position, in which the switching element is open. In the unlocked position, a rotationally fixed connection between two elements can be released. The switching element can be moved in a closing direction so that it can be brought into the locked position. The switching element can be moved, for example, opposite to the closing direction, so that the switching element can be opened. The closing direction can, for example, be an axial direction of the first output shaft. Alternatively or additionally, the closing direction can include directions other than the axial direction, for example, directions with a radial component or a circumferential component.The switching element can be designed, for example, as a sliding sleeve, a clutch or a brake.

[0008] The first output shaft is rotationally fixed to the second output shaft via the first switching element, which is in its locked position. The first output shaft can be arranged sectionally within the second output shaft in both the axial and radial directions. The radial direction can be perpendicular to the axis of rotation of the input element. The first and second output shafts can extend in opposite directions from their axial overlap area.

[0009] The first switching element can be part of a differential locking device, which may include further components for providing a differential locking function. The first switching element can be displaceable relative to the first output shaft in its closing direction. The first switching element can be designed as a sliding sleeve. The first switching element can be ring-shaped. The first switching element can be permanently and rotationally fixed to the first output shaft, regardless of its position along the closing direction. The first switching element can be rotationally fixed to the second output shaft by means of a displacement in the closing direction. The first switching element can also be rotationally fixed to the second output shaft in its locked position. The first switching element can be detached from the second output shaft in its unlocked position.In an alternative embodiment, the first switching element can be permanently connected to the second output shaft in a rotationally fixed manner and can be connected to the first output shaft in a rotationally fixed manner by a displacement in the closing direction.

[0010] The first output shaft is non-rotatably connected to the coupling element and, via the second switching element in its locked position, to the first wheelset. The second switching element can be part of a decoupling device, which may include further components for providing a decoupling function. The second switching element can be displaceable relative to the first output shaft in its closing direction. The second switching element can be designed as a sliding sleeve. The second switching element can be annular in design. The second switching element can be permanently non-rotatably connected to the first output shaft, regardless of its position along the closing direction. The second switching element can be non-rotatably connected to the coupling element by a displacement in the closing direction. The second switching element can also be non-rotatably connected to the coupling element in its locked position.The second switching element can be detached from the coupling element in its unlocked position. In an alternative embodiment, the second switching element can be permanently and rotationally fixedly connected to the coupling element and can be rotationally fixedly connected to the first output shaft by a displacement in the closing direction.

[0011] The differential gear described in the first aspect provides a differential locking function with a simple design, allowing the first output shaft to be locked relative to the second output shaft. This improves driving safety, for example, in poor traction conditions. Furthermore, the second switching element allows the first output shaft to be locked and unlocked relative to the coupling element. The differential gear is designed for a disengagement function. When the second switching element is in its unlocked position, the rotationally fixed connection between the first gear set and the first output shaft is released. Consequently, rotation initiated in the first output shaft does not cause the first gear set to rotate. Depending on the differential gear design, however, rotation initiated in the second output shaft may still cause the gear sets to rotate.For example, a situation may arise in which the torque flow from the second output shaft is to be split between the input element and one element of the first gear set. Whether and to what extent this leads to rotation of the input element can be influenced by the design of the differential. For instance, the differential can be designed such that the input element and the components in the torque flow up to that point have a greater moment of inertia than the single element of the first gear set. Alternatively, the differential can be designed such that the moment of inertia of the drive unit connected to the input element exceeds the moment of inertia of the single element of the first gear set by a factor of several. In such designs, the drive unit is not set into rotation, or only to a negligible extent.The differential gear, therefore, with its simple design, is able to provide the decoupling function in which both output shafts can rotate freely without significantly driving the input element and the drive unit that can be connected to it.

[0012] In one embodiment, the differential gear has a preload element for the first shifting element, which biases the first shifting element towards its unlocked position. The preload element for the first shifting element can be coaxial with the first output shaft. The preload element for the first shifting element can be located radially within and supported by the first output shaft. For example, the preload element for the first shifting element can be located in a cylindrical bore in the first output shaft. The cylindrical bore can be concentric with the first output shaft. Alternatively, the preload element for the first shifting element can be located radially outside the first output shaft. The preload element for the first shifting element can be supported by the second output shaft. The preload element for the first shifting element can be a spring element.For example, the preload element for the first switching element can be designed as a coil spring. Alternatively, the preload element for the first switching element can be formed by a multitude of stacked disc springs. The disc springs can be stacked in the closing direction. Since the first switching element is preloaded to its unlocked position, the differential lock can be released passively. This simplifies the design of the differential gear.

[0013] In one embodiment, the differential gear includes a preload element for the second shifting element, which biases the second shifting element towards its unlocked position. The preload element for the second shifting element can be coaxial with the first output shaft. The preload element for the second shifting element can be located radially inside and supported by the first output shaft. For example, the preload element for the second shifting element can be located in a cylindrical bore in the first output shaft. The cylindrical bore can be concentric with the first output shaft. The cylindrical bore for the second preload element can be the same as the cylindrical bore for the first preload element or it can be different. Alternatively, the preload element for the second shifting element can be located radially outside the first output shaft.The preload element for the second switching element can be supported on the coupling element. The preload element for the second switching element can be a spring element. For example, the preload element for the second switching element can be a coil spring. Alternatively, the preload element for the second switching element can be formed by a multitude of stacked disc springs. The disc springs can be stacked in the closing direction. Since the second switching element is preloaded to its unlocked position, decoupling is achieved passively.

[0014] In one embodiment, a switching element equipped with a preload element is axially displaceable. The differential gear has a retaining ring by which the preload element is axially supported on an output shaft. The retaining ring can be received in a groove on the inner diameter of a cylindrical bore. The cylindrical bore for receiving the retaining ring can be continuous with or identical to the cylindrical bore for receiving the preload element. The retaining ring can support one or more preload elements.

[0015] In one embodiment, the differential gear comprises a piston, a connecting element, and a chamber. The chamber is formed within one of the output shafts. The piston is axially displaceable between a preload element and the chamber. One of the switching elements is connected to the piston by means of the connecting element. Movement of the piston allows the switching element to be moved to its locked and unlocked positions. The preload element and the chamber can be arranged within one of the output shafts. The piston can be arranged within one of the output shafts. The piston can be coaxial with one of the output shafts. The piston can be contained within the chamber. The chamber can be pressurized. The piston can be moved in one direction by pressurizing the chamber.The piston can be moved in the opposite direction by force applied by the preload element. The cylindrical bore for receiving the preload element must not contain pressurized fluid. For example, the cylindrical bore can be designed as a vent or hydraulic fluid drain bore.

[0016] The connecting element can be designed as a cylindrical pin. The connecting element can extend radially through the piston and one of the switching elements. The connecting element can be riveted to opposite ends of the outer circumference of one of the switching elements on both sides. The connecting element can extend through a guide recess in one of the output shafts. The guide recess can be designed as an elongated slot. One of the output shafts can have two radially opposite guide recesses.

[0017] The chamber can be designed as a cylindrical bore. If the preload element is housed in a cylindrical bore, the cylindrical bore for housing the preload element can be continuous with the chamber and have the same inner diameter. Alternatively, the chamber and the cylindrical bore for housing the preload element can have different inner diameters. The piston can have a sliding section that rests against an inner diameter of the chamber. The inner diameter of the chamber can be essentially equal to an outer diameter of the piston's sliding section. The piston can be partially hollow in a region of the sliding section. The piston can be thin-walled in a region of the sliding section.

[0018] The differential gear can have multiple pistons, connecting elements, chambers, and / or preload elements. For example, the differential gear can have one piston, one connecting element, one chamber, and one preload element per shift element. Alternatively or additionally, one or more of these components can be provided jointly for multiple shift elements. For example, one preload element can be designed to preload multiple shift elements. Furthermore, some or all shift elements can be provided without some or all of these components.

[0019] In one embodiment, the first switching element and the second switching element are each connected to a piston, which can be printed via a chamber. In one embodiment, the chamber for the first switching element and the chamber for the second switching element are formed in the same output shaft.

[0020] In one embodiment, a fluid channel for printing the chamber of one of the switching elements extends at least partially in a radial direction along the output shaft in which the chambers are formed. A fluid channel for printing the chamber of the other switching element extends at least partially in an axial direction along the output shaft. The respective chamber can be supplied with hydraulic fluid via its respective fluid channel to pressurize it. The hydraulic fluid can be a lubricant for lubricating elements of a gear set. Each fluid channel can extend at least partially in the radial direction and, alternatively or additionally, at least partially in the axial direction.

[0021] The fluid channel for printing the chamber of one of the switching elements can extend from an outer circumference of the first output shaft to the chamber. The fluid channel for printing the chamber of one of the switching elements can extend from an outer circumference of the second output shaft through the first output shaft to the chamber. A fluid channel for printing the chamber of the other switching element extends at least partially in an axial direction along one output shaft. The fluid channel for printing the chamber of the other switching element can extend completely or partially in the axial direction along one output shaft. In one embodiment, the fluid channel for printing the chamber of the other switching element can extend from an axial end of one output shaft to the chamber.The fluid channel for printing the chamber of the other switching element can also have a radial and / or inclined section connecting an outer circumference of one output shaft to an axial section of the fluid channel. The fluid channel for printing the chamber of the other switching element can open at an end face of one output shaft.

[0022] At least one of the fluid channels can have an annular gap arranged radially between the first and second output shafts. Sealing elements can be provided on both sides of such a fluid channel in the axial direction. These sealing elements can create a fluid-tight seal around the annular gap on one side. The sealing elements can extend circumferentially. For example, the sealing elements can be designed as rectangular seals. The fluid channel can be configured with bores through the first output shaft, and optionally also through the second output shaft. At least one of the first and second output shafts can have multiple bores. The bores can be distributed circumferentially. The bores can be uniformly distributed circumferentially.One or more bores can open into an end face of one output shaft, into an outer circumference of the first output shaft, into an outer circumference of the second output shaft and / or into the annular gap.

[0023] In one embodiment, an inner torque transmission element for an output shaft is configured on the inner circumference of a section of one of the switching elements. An outer torque transmission element for a shaft is configured on the outer circumference of a section of the switching element. The first output shaft can be connected to the shaft in a rotationally fixed manner via the inner and outer torque transmission elements. The shaft can be a torque transmission element. For example, the shaft can be the second output shaft or the coupling element. One or more switching elements can be provided with the aforementioned configuration. For example, the first switching element can have torque transmission elements for connecting the first output shaft to the second output shaft, and the second switching element can have torque transmission elements for connecting the first output shaft to the coupling element.

[0024] At least one of the torque transmission elements can have a splined profile, for example, a keyed shaft profile. Corresponding torque transmission elements, for example, splined profiles, can be formed on the first output shaft and on the shaft. One of the switching elements can be arranged in a gap in the radial direction between the first output shaft and the shaft.

[0025] One switching element can be permanently and rotationally fixed to the first output shaft, or selectively and rotationally fixed to the shaft. For example, the torque transmission element on the first output shaft can be present across the entire axial range of motion of the switching element between the unlocked and locked positions. The torque transmission element on the shaft can be present only in a portion of the axial range of motion. For example, the torque transmission element for the shaft can be present only in the locked position and not in the unlocked position. With the switching element in the locked position, the torque transmission element for the shaft can thus engage with the torque transmission element on the shaft, resulting in a rotationally fixed connection between the first output shaft and the shaft.With the switching element in the unlocked position, the torque transmission element for the shaft cannot engage with the torque transmission element on the shaft, so the first output shaft and the shaft are not rotationally fixed. Alternatively, the torque transmission element on the first output shaft can be configured only in a portion of its axial range of motion, while the torque transmission element on the shaft can be configured in its entire axial range of motion. In both cases, the connection is established using the same mechanism.

[0026] In one embodiment, the first gear set is formed by a first planetary gear set, and the second gear set is formed by a second planetary gear set. The first and second planetary gear sets can be arranged axially in the same plane. The second planetary gear set can be arranged radially outside the first planetary gear set. The first and second planetary gear sets can be arranged axially offset from each other.

[0027] In one embodiment, the first planetary gear set comprises at least one first element, for example a first sun gear, a second element, for example a first planet carrier, and a third element, for example a first ring gear. The second planetary gear set comprises at least one first element, for example a second sun gear, a second element, for example a second planet carrier, and a third element, for example a second ring gear. The input element is rotationally fixed to the first element of the first planetary gear set. The input element can, for example, form the first element on an outer circumference of the first planetary gear set. The second element of the first planetary gear set is rotationally fixed to the first output shaft via the coupling element. The third element of the first planetary gear set is rotationally fixed to the first element of the second planetary gear set.The second element of the second planetary gear set is non-rotatably connected to a stationary component. This stationary component can be a housing, for example, a gearbox housing. The third element of the second planetary gear set is non-rotatably connected to the second output shaft.

[0028] The first planetary gear set can comprise the first sun gear, the first planet carrier, a first planet pin, a first planet gear, and the first ring gear. The first sun gear can mesh with the first planet gear. The first planet gear can mesh with the first ring gear. The first planet gear can be rotatably mounted on the first planet pin. The first planet pin can be fixed to the first planet carrier. The second planetary gear set can comprise the second sun gear, a second planet carrier, a second planet pin, a second planet gear, and a second ring gear. The second sun gear can mesh with the second planet gear. The second planet gear can mesh with the second ring gear. The second planet gear can be rotatably mounted on the second planet pin. The second planet pin can be fixed to the second planet carrier. The third element of the first planetary gear set, i.e.,The first ring gear, and the first element of the second planetary gear set, i.e. the second sun gear, can be formed in one piece as a sun ring gear.

[0029] In one embodiment, the differential gear has an actuating device. The switching elements can be moved to their locked position by means of the actuating device, optionally against a preload force of their preloading element. The switching elements can be moved to the unlocked position by means of the preloading element, or alternatively or additionally by means of the actuating device. The actuating device can include a hydraulic actuator, optionally an electromagnetic valve. The electromagnetic valve can be configured to provide two positions corresponding to the unlocked position and the locked position of the respective switching element.

[0030] In one embodiment, the differential gear includes a control unit for controlling the switching states of the differential gear. The control unit can be configured, for example, by programming. The control unit and the preload elements can be configured to interact in order to influence the respective switching elements. Control can also include refraining from an actuation or action, such as pressing. The control unit can, for example, be configured not to counteract the preload of a switching element, for instance, by depressurizing the associated chamber. Then, due to the preload from the preload element, one switching element is moved into the unlocked position. The control unit is configured to open the first switching element and close the second switching element for a driving switching state.The driving mode can be a switching state of the differential gear in which the differential gear distributes a torque introduced via the input element to the first output shaft and the second output shaft, allowing a speed difference between the output shafts. The control unit is configured to close the first and second switching elements for a differential lock switching state. Alternatively, the differential lock switching state can be a switching state of the differential gear in which the differential gear applies a torque introduced via the input element to the first and second output shafts, preventing a speed difference between the output shafts. The control unit is configured to open the first and second switching elements for a disengagement switching state.The decoupling switching state can be a switching state of the differential gear in which decoupling is activated. Accordingly, in the decoupling switching state, the differential gear allows free rotation of the output shafts, while the input element is not substantially driven.

[0031] The present disclosure relates in a second aspect to a vehicle comprising a drive unit, at least two drive elements, and a differential gear according to the first aspect. The drive unit is configured to drive the input element. One of the drive elements is configured to drive the vehicle via the first output shaft. The other drive element is configured to drive the vehicle via the second output shaft. The respective advantages and further features are described in the first aspect, with embodiments of the first aspect also constituting embodiments of the second aspect and vice versa. Brief description of the characters Fig. Figure 1 shows a vehicle with a differential gear according to an embodiment of the present disclosure. Fig. Figure 2 schematically shows a wiring diagram of the vehicle's differential gear. Fig. 1. Fig. Figure 3 shows a schematic sectional view of a differential gear according to an embodiment of the present disclosure in a driving switching state. Fig. Figure 4 shows a schematic sectional view of the differential gear. Fig. 3 in a differential lock switching state. Fig. Figure 5 shows a schematic sectional view of the differential gear. Fig. 3 in a disconnect switching state. Detailed description of embodiments

[0032] Fig. Figure 1 shows a vehicle 100. The vehicle 100 is equipped with a differential gear 1 and a drive unit 2. The differential gear 1 serves to drive a left drive element 101 and a right drive element 102 of the vehicle 100. The drive elements 101 and 102 are designed as wheels. The drive unit 2 is designed as an electric motor for driving the vehicle 100 by introducing torque into the differential gear 1. The vehicle 100 also has a control device 80, described later, for controlling the switching states of the differential gear 1.

[0033] Fig. Figure 2 shows a general wiring concept for the differential gear 1. The differential gear 1 is a differential gear with two planetary gear sets. As shown from Fig. As can be seen in Figure 2, the differential 1 comprises a first planetary gear set 10 with a first element 11, a second element 12, and a third element 13. Furthermore, the differential 1 comprises a second planetary gear set 20 with a first element 21, a second element 22, and a third element 23. A torque from the drive unit 2 can be introduced into the differential 1 via the first element 11 of the first planetary gear set 10. For this purpose, an input element 4 is mechanically connected to the first element 11 of the planetary gear set 10, in this case permanently and rotationally fixed. The third element 13 of the first planetary gear set 10 is permanently and rotationally fixed to the first element 21 of the second planetary gear set 20, in this case by being formed as a single piece. The second element 22 of the second planetary gear set 20 is permanently and rotationally fixed to a stationary component, in this case a gearbox housing 9.The second element 12 of the first planetary gear set 10 is mechanically connected to a first output shaft 5, in this case via a decoupling device 72 for the purpose of a decoupling function. The third element 23 of the second planetary gear set 20 is mechanically connected to a second output shaft 6, in this case permanently and non-rotatably connected. The first output shaft 5 and the second output shaft 6 are non-rotatably connected by a differential locking device 70 for the purpose of a differential locking function.

[0034] Fig. Figure 3 shows a sectional view of an embodiment of a differential gear 1 in a driving-shift state. The differential gear 1 is designed according to Fig. 2 shifted. The differential gear 1 is for use with vehicle 100 from Fig. 1 suitable. The differential gear 1 has a first planetary gear set 10, a second planetary gear set 20, an input element 4, a first output shaft 5, a second output shaft 6 and a gear housing 9.

[0035] The first planet gear set 10 comprises a first sun gear, corresponding to the first element 11, a first planet carrier, corresponding to the second element 12, a number of first planet pins 15, a number of first planet gears 14, and a first ring gear, corresponding to the third element 13. The first sun gear 11 meshes with one of the first planet gears 14. One of the first planet gears 14 meshes with the first ring gear 13 and is rotatably mounted on one of the first planet pins 15. The first planet pins 15 are connected to the first planet carrier 12.

[0036] The second planetary gear set 20 comprises a second sun gear 21, corresponding to the first element 21, a second planet carrier 22, corresponding to the second element 22, a number of second planet pins 25, a number of second planet gears 24, and a second ring gear 23, corresponding to the third element 23. The second sun gear 21 meshes with one of the second planet gears 24. One of the second planet gears 24 meshes with the second ring gear 23 and is rotatably mounted on one of the second planet pins 25. The second planet pins 25 are connected to the second planet carrier 22. The second planet carrier 22 is rotationally fixed to the gearbox housing 9.

[0037] The first planetary gear set 10 and the second planetary gear set 20 are arranged in the same plane, i.e., at the same axial height, in the axial direction of the first output shaft 5. The second planetary gear set 20 is arranged radially outside the first planetary gear set 10. The input element 4, the first output shaft 5, and the second output shaft 6 are arranged coaxially with each other. The first output shaft 5 extends partially inside the second output shaft 6. In this case, the first output shaft 5 is rotatably mounted in the second output shaft 6 by means of a bearing 7. The first output shaft 5 and the second output shaft 6 extend axially in opposite directions from their overlapping area.

[0038] The input element 4 is located on a first side, namely the left side in Fig. 3, designed for connection to the drive unit 2. The input element 4 forms the first sun gear 11 of the first planetary gear set 10 on an outer circumference of an end section of the input element 4 on a second side, namely the right side in Fig. 3. The input element 4 is thus configured to transmit torque to the first planetary gear set 10. The first planet carrier 12 can be selectively and rotationally fixedly connected to the first output shaft 5 to output torque from the first planetary gear set 10. In this case, the rotationally fixed connection of the first output shaft 5 to a coupling element 18 and via this to the first planet carrier 12 is achieved by a splined connection, in this case with a splined shaft profile. Thus, the first output shaft 5 is configured to selectively receive torque from the first planetary gear set 10. The coupling element 18 is configured in this case as a hub of the first planet carrier 12. The second ring gear 23 is rotationally fixedly connected to the second output shaft 6 to output torque from the second planetary gear set 20. Thus, the second output shaft 6 is configured to receive torque from the second planetary gear set 20.

[0039] The first ring gear 13 and the second sun gear 21 are here formed in one piece as a sun gear 30. The sun gear 30 has the first ring gear 13 on its inner circumference. The sun gear 30 has the second sun gear 21 on its outer circumference. This mechanically connects the first planet gear set 10 to the second planet gear set 20.

[0040] The differential gear 1 has a first switching element 50. The first switching element 50 is part of a differential locking device 70. The differential locking device comprises the first switching element 50, a piston 51, a connecting element 52, and a preload element 54. The first switching element 50 can be moved axially between a locking position and an unlocking position by means of an actuating device (not shown). By moving the first switching element 50 axially, the first output shaft 5 can be connected to the second output shaft 6 in a rotationally fixed manner. The first switching element 50 is then in the locking position, and the differential gear 1 is in a differential locking state, which will be described later.

[0041] The differential gear 1 has a second switching element 40. The second switching element 40 is part of a decoupling device 72. The decoupling device comprises the second switching element 40, a piston 41, a connecting element 42, and a preload element 44. The second switching element 40 can be moved axially between a locking position and an unlocking position by means of the actuating device. By moving the second switching element 40 axially towards the locking position, in this case to the right, the first output shaft 5 can be connected to the coupling element 18 in a rotationally fixed manner. The second switching element 40 is then in the locking position, and the differential gear 1 is in the driving mode, which will be described later. By moving the second switching element 40 axially towards the unlocking position, in this case to the left, the first output shaft 5 can be disconnected from the coupling element 18.Then the differential gear 1 is in a decoupling switching state, which will be described later.

[0042] The first switching element 50 is arranged in a gap between the first output shaft 5 and the second output shaft 6. The second switching element 40 is arranged in a gap between the first output shaft 5 and the coupling element 18. The piston 51, the first output shaft 5, the first switching element 50, and the second output shaft 6 are stacked radially in this order from the inside out. The piston 41, the first output shaft 5, the second switching element 40, and the coupling element 18 are stacked radially in this order from the inside out. The switching elements 40 and 50 are each designed as annular sliding sleeves. Each switching element 40 and 50 has a torque transmission element 45 and 55 for the first output shaft 5 on its inner circumference.The first switching element 50 and the second switching element 40 are rotationally fixed to the first output shaft 5 via the torque transmission element 45, 55 for the first output shaft 5. The switching elements 40, 50 are axially displaceable relative to the first output shaft 5. The first switching element 50 has a torque transmission element 56 for the second output shaft 6 on its outer circumference. By axially displacing the first switching element 50, it can be rotationally fixed to the second output shaft 6 via the torque transmission element 56, as will be described later. The second switching element 40 has a torque transmission element 46 for the coupling element 18 on its outer circumference.By shifting the second switching element 40 in the axial direction, the second switching element 40 can be connected to the coupling element 18 in a rotationally fixed manner via the torque transmission element 46 for the coupling element 18, which will be described later.

[0043] The torque transmission elements 45, 55 for the first output shaft 5, the torque transmission element 56 for the second output shaft 6, and the torque transmission element 46 for the coupling element 18 are designed as splined connections, in this case with a splined shaft profile. The first output shaft 5, the second output shaft 6, and the coupling element 18 have corresponding splined profiles. In this case, the splined profile for the torque transmission element 45 transitions into the splined profile for the torque transmission element 55, which provides a rotationally fixed connection between the first output shaft 5, the coupling element 18, and the first planet carrier 12.

[0044] The first switching element 50 is connected to the piston 51 via the connecting element 52. The connecting element 52 is designed as a cylindrical pin. The connecting element 52 extends radially through the piston 51 and the first switching element 50. On an outer surface of the first switching element 50, the connecting element 52 is riveted on both sides, on a top and a bottom surface. The connecting element 52 passes through a guide recess 53, in this case an elongated hole, of the first output shaft 5. Within the guide recess 53, the connecting element 52 is axially displaceable. The second switching element 40 is connected to the piston 41 via the connecting element 42. The connecting element 42 is designed as a cylindrical pin. The connecting element 42 extends radially through the piston 41 and the second switching element 40.On an outer surface of the second switching element 40, the connecting element 42 is riveted on both sides at a top and a bottom. The connecting element 42 is guided through a guide recess 43, in this case an elongated hole, of the first output shaft 5. Within the guide recess 43, the connecting element 42 is axially displaceable.

[0045] The pistons 41 and 51 are arranged radially and axially within the first output shaft 5. Each piston 41 and 51 has a sliding section on its outer circumference that is in contact with an inner circumference of the first output shaft 5. The pistons 41 and 51 are axially displaceable within the first output shaft 5. The sliding section of each piston 41 and 51 is partially hollow. The sliding section seals an axially first side of each piston 41 and 51 against each other.

[0046] A first chamber 61 is located on the second side, namely the right side in Fig. 3, of the piston 51 is arranged within the first output shaft 5. The first chamber 61 is closed at one end of the first output shaft 5 in the axial direction on the right side by means of an end cap 67. The end cap 67 is supported against the pressure in the first chamber 61 by a retaining ring 68, which in this case is designed as a snap ring received in a groove. The first chamber 61 is in fluid communication with the actuating device via a first fluid channel 63. The first chamber 61 is selectively supplied with pressurized hydraulic fluid via the first fluid channel 63 by the actuating device in order to be pressurized. The first fluid channel 63 extends radially through the first output shaft 5 and through the second output shaft 6.In the radial direction between the first output shaft 5 and the second output shaft 6, two sealing elements 65, in this case rectangular seals, are arranged on both sides of the fluid channel 63 in the axial direction, extending in a circumferential direction. The sealing elements 65 seal an annular gap formed by the sealing elements 65 and the output shafts 5, 6.

[0047] A second chamber 62 is located on the first side, namely the left side in Fig. 3, of the piston 41 is arranged within the first output shaft 5. The second chamber 62 is in fluid communication with the actuating device via a second fluid channel 64. The second chamber 62 is selectively supplied with pressurized hydraulic fluid via the second fluid channel 64 by the actuating device in order to be pressurized. The second fluid channel 64 extends axially through the first output shaft 5.

[0048] The preload elements 44 and 54 are slidably mounted in a common cylindrical bore 58. The cylindrical bore 58 extends concentrically to the left from a right end face of the first output shaft 5 in the axial direction within the first output shaft 5. On the right side, the cylindrical bore 58 transitions into the first chamber 61, and on the left side, it transitions into the second chamber 62. The preload element 54 is axially supported on the left side of the first output shaft 5 by a retaining ring 57, which in this case is a snap ring mounted in a groove. The preload element 54 is designed as a helical spring. The preload element 54 applies a preload to the piston 51 in the direction of the unlocked position, in this case to the right.The preload element 44 is also axially supported on the right side of the first output shaft 5 by the retaining ring 57. In a further embodiment, the preload element 44 is supported by an additional retaining ring. The preload element 44 is designed as a coil spring. The preload element 44 applies a preload to the piston 41 in the direction of the unlocked position, in this case to the left.

[0049] The control unit 80 is for controlling the functions relating to Fig. The differential gear switching states described in sections 3 to 5 below are configured. The control unit 80 is designed to control the switching elements 40 and 50 independently of each other with respect to their locking and unlocking positions via hydraulic pressure from the actuating device. In this case, the control unit 80 can selectively pressurize chambers 61 and 62 to move the respective switching element 50 or 40 into the locking position. To move the respective switching element 50 or 40 into the unlocking position, the control unit 80 can depressurize chamber 61 or 62, allowing the preloading element 54 or 44 to move the switching element 50 or 40 into the unlocking position.

[0050] The piston 51, together with the connecting element 52 and the first switching element 50, can be moved to the right by means of the preloading element 54. The piston 51, together with the connecting element 52 and the first switching element 50, can be moved to the left by means of the printing on the first chamber 61. The piston 41, together with the connecting element 42 and the second switching element 40, can be moved to the left by means of the preloading element 44. The piston 41, together with the connecting element 42 and the second switching element 40, can be moved to the right by means of the printing on the second chamber 62.

[0051] Fig. Figure 3 shows the driving mode of the differential 1, in which the first switching element 50 is in the unlocked position by depressurizing the first chamber 61 and by preloading the preload element 54. The first output shaft 5 is then non-rotatably connected to the second output shaft 6 via the torque transmission element 55 for the first output shaft 5 and the torque transmission element 56 for the second output shaft 6. This allows a speed difference between the first output shaft 5 and the second output shaft 6 during the driving mode. The second switching element 40 is in the locked position by pressing on the second chamber 62. This allows the first output shaft 5 to receive torque from the first gear set 10 via the coupling element 18 and thus be driven during the driving mode.

[0052] Fig. Figure 4 shows a sectional view of an embodiment of the differential locking device of the differential gear 1 in a differential locking switching state. In the state of Fig. In section 4, the first switching element 50 is positioned in the locking position by printing on the first chamber 61. The first output shaft 5 is then rotationally fixed to the second output shaft 6 via the torque transmission element 55 for the first output shaft 5 and the torque transmission element 56 for the second output shaft 6. This prevents a speed difference between the first output shaft 5 and the second output shaft 6 when the differential is locked. The second switching element 40 is positioned in the locking position by printing on the second chamber 62. This allows the first output shaft 5 to receive torque when the differential is locked.

[0053] Fig. Figure 5 shows a sectional view of an embodiment of the differential locking device of the differential gear 1 in a disengaged switching state. In the state of Fig. In the first switching element 50, the preload element 54 is positioned in the unlocked position. The second switching element 40 is positioned in the unlocked position by the preload element 44. This allows the first output shaft 5 and the second output shaft 6 to rotate freely in the disconnected switching state without significant driving of the input element and the drive unit. Reference sign 1 Differential gear 2 Drive unit 4. Entrance element 5 first output wave 6 second output wave 7 warehouses 9 stationary component 10 first planetary gear set 11. First sun gear, first element of the first planetary gear set 12 first planet carrier, second element of the first planet gear set 13 first ring gear, third element of the first planetary gear set 14 first planetary gear 15 first planetary bolt 18 coupling element 20 second planetary gear set 21 second sun gear, first element of the second planetary gear set 22 second planet carrier, second element of the second planet gear set 23 second ring gear, third element of the second planetary gear set 24 second planetary gear 25 second planetary bolt 30 Sunburst wheel 40 second switching element 41 pistons 42 Connecting element 43 Guide recess 44 Preload element 45 internal torque transmission element 46 external torque transmission element 50 first switching element 51 pistons 52 Connecting element 53 Guide recess 54 Preload element 55 internal torque transmission element 56 external torque transmission element 57 Retaining ring 58 cylindrical bore 61 first chamber 62 second chamber 63 first fluid channel 64 second fluid channel 65 Sealing element 67 End cap 68 retaining ring 70 Differential locking device 72 Disconnection device 80 Control unit 100 vehicles 101 first driving element 102 second driving element

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