GEAR UNIT FOR A VEHICLE AND POWERTRAIN WITH SUCH A GEAR UNIT

Abstract

A gear unit has a differential with two planetary gearsets and gearset elements. A first gearset element of the first planetary gearset is connected to an input shaft, a second gearset element of the first planetary gearset is connected to a first output shaft, a third gearset element of the first planetary gearset is connected to a first gearset element of the second planetary gearset, a second gearset element of the second planetary gearset is connected to a housing, and a third gearset element of the second planetary gearset is connected to a second output shaft. A first output torque is transmittable to the first output shaft. A second output torque is transmittable to the second output shaft. An actuation mechanism is arranged between the first and second output shafts for a co-rotationally fixed connection between the output shafts when the actuation mechanism is actuated.

Claims

1. A gear unit for a powertrain of a vehicle, comprising: an input shaft; a first output shaft; a second output shaft; an integral differential operatively arranged between the input shaft and the first output shaft and the second output shaft, wherein the integral differential comprises: a first planetary gearset with a plurality of gearset elements; a second planetary gearset with a plurality of gearset elements operatively connected to the first planetary gearset, wherein: a first gearset element of the first planetary gearset is connected to the input shaft to be fixed with respect to rotation relative to it; a second gearset element of the first planetary gearset is connected to the first output shaft to be fixed with respect to rotation relative to it, a third gearset element of the first planetary gearset is connected to a first gearset element of the second planetary gearset to be fixed with respect to rotation relative to it, a second gearset element of the second planetary gearset is connected to a stationary structural component to be fixed with respect to rotation relative to it, and a third gearset element of the second planetary gearset is connected to the second output shaft to be fixed with respect to rotation relative to it, a first output torque is at least indirectly transmittable to the first output shaft by the first planetary gearset, and a reaction torque of the first planetary gearset is converted in the second planetary gearset such that a second output torque corresponding to the first output torque is transmittable to the second output shaft; and an actuation mechanism is operatively arranged between the first output shaft and the second output shaft and having at least one positive engagement element, wherein the at least one positive engagement element is configured to produce a co-rotationally fixed connection between the first output shaft and the second output shaft when the actuation mechanism is actuated.

2. The gear unit according to claim 1, wherein the at least one positive engagement element is a claw which is at least indirectly arranged at the second output shaft to be fixed with respect to relative rotation and axially displaceable and has a first face toothing, the claw configured to be axially displaced such that when the actuation mechanism is actuated that a first face toothing comes in meshing engagement with a second face toothing which is at least indirectly arranged at the first output shaft.

3. The gear unit according to claim 2, further comprising a plurality of positive engagement elements arranged to be distributed on a common ring.

4. The gear unit according to claim 1, wherein the actuation mechanism is an electromagnetic actuator, a hydraulic actuator, or an electromechanical actuator.

5. The gear unit according to claim 3, wherein the claw and/or the common ring are/is a magnetic material, wherein the actuation mechanism is an electromagnetic that magnetically interacts with the claw and/or common ring when correspondingly activated to displace the claw and/or the common ring with the claw arranged thereon in direction of the second face toothing.

6. The gear unit according to claim 5, wherein the actuation mechanism has a reset mechanism configured to reset the claw and/or the common ring to an initial position.

7. The gear unit according to claim 3, wherein the common ring is configured to interact with a sensor unit to acquire an axial position of the common ring.

8. A powertrain for a vehicle, comprising: at least one gear unit, comprising: an input shaft; a first output shaft; a second output shaft; an integral differential operatively arranged between the input shaft and the first output shaft and the second output shaft, wherein the integral differential comprises: a first planetary gearset with a plurality of gearset elements; a second planetary gearset with a plurality of gearset elements operatively connected to the first planetary gearset, wherein: a first gearset element of the first planetary gearset is connected to the input shaft to be fixed with respect to rotation relative to it; a second gearset element of the first planetary gearset is connected to the first output shaft to be fixed with respect to rotation relative to it, a third gearset element of the first planetary gearset is connected to a first gearset element of the second planetary gearset to be fixed with respect to rotation relative to it, a second gearset element of the second planetary gearset is connected to a stationary structural component to be fixed with respect to rotation relative to it, and a third gearset element of the second planetary gearset is connected to the second output shaft to be fixed with respect to rotation relative to it, a first output torque is at least indirectly transmittable to the first output shaft by the first planetary gearset, and a reaction torque of the first planetary gearset is converted in the second planetary gearset such that a second output torque corresponding to the first output torque is transmittable to the second output shaft; and an actuation mechanism is operatively arranged between the first output shaft and the second output shaft and having at least one positive engagement element, wherein the at least one positive engagement element is configured to produce a co-rotationally fixed connection between the first output shaft and the second output shaft when the actuation mechanism is actuated; and a drive unit which is operatively connected to the at least one gear unit.

9. The powertrain according to claim 8, wherein the drive unit is arranged coaxial to the integral differential.

10. The powertrain according to claim 8, wherein the drive unit is an electric machine and is arranged coaxial to the input shaft, wherein the first output shaft is guided through a rotor of the electric machine.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] An embodiment example of the invention will be explained more fully in the following referring to the schematic drawings. The drawings show:

[0051] FIG. 1 a highly schematic top view of a vehicle with a powertrain according to the invention and a gear unit according to the invention in a first embodiment form; and

[0052] FIG. 2 a highly schematic diagram of the gear unit according to the invention from FIG. 1 with an actuation mechanism in the unactuated state;

[0053] FIG. 3 a schematic longitudinal section through the gear unit according to the invention from FIG. 2 with the actuation mechanism in the unactuated state;

[0054] FIG. 4 a highly schematic diagram of the gear unit according to the invention according to FIG. 1 to FIG. 3 in the actuated state of the actuation mechanism; and

[0055] FIG. 5 a schematic longitudinal section through the gear unit according to the invention from FIG. 4 in the actuated state of the actuation mechanism.

DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS

[0056] FIG. 1 shows a vehicle 1 with two axles 11a, 11b. A powertrain 2 according to the invention is drivingly arranged at the first axle 11a. The first axle 11a may be a front axle or rear axle of the vehicle 1 and forms a driven axle of the vehicle 1. Further, it is conceivable that the second axle 11b also has a powertrain 2 according to the invention. The powertrain 2 comprises a drive unit 22 constructed as an electric machine and a gear unit 3 which is operatively connected to the latter. The construction and the arrangement of the powertrain 2 in the vehicle 1, in particular the gear unit 3, will be explained in more detail in the following figures. An exemplary drive unit 22 is shown in FIG. 1 and FIG. 2. This will be omitted in the following figures for the sake of simplicity. Only an input shaft 4 is shown, this input shaft 4 being drivingly connected to the drive unit 22 for transmitting a torque into the gear unit 3. The electric machine is supplied with electrical energy by an accumulator—not shown—which is operatively connected to a stator 19, shown in FIG. 2, which is fixed with respect to the housing. Further, the electric machine is connected to power electronics—not shown—for controlling and adjusting. By energizing the stator 19 of the electric machine, a rotor 20 which is arranged to be rotatable relative to the stator 19 and which is in turn connected as drive shaft to the input shaft 4 of the gear unit 3 to be fixed with respect to rotation relative to it is set in rotational motion relative to the stator 19. Alternatively, the input shaft 4 can also be connected to or coupled with a separate rotor shaft of the rotor 20 to be fixed with respect to rotation relative to it. Accordingly, the propulsion power of the drive unit 22 is guided via the input shaft 4 into the gear unit 3, where it is converted by an integral differential 7 and at least indirectly divided between a first output shaft 5 and a second output shaft 6. The drive unit 22 comprising the stator 19 and the rotor 20 is arranged coaxial to the integral differential 7.

[0057] The output shafts 5, 6, which are arranged coaxial to one another are indirectly connected in each instance to a wheel 18, shown in FIG. 1, of the first axle 11a in order to drive the vehicle 1. Joints 21 and wheel hubs 23 are arranged between the respective wheel 18 and the output shafts 5, 6 in order to compensate possible tilting of the output shafts 5, 6. Consequently, the vehicle 1 is an electric vehicle, and the drive is carried out fully electrically.

[0058] FIGS. 2 to 5 show a preferred embodiment of the gear unit 3 in two different states, which will be explained in the following. The respective gear unit 3 is a differential gear and in the present instance comprises the input shaft 4, a first output shaft 5 and a second output shaft 6. The output shafts 5, 6 are arranged coaxial to the integral differential 7 and extend in opposite directions toward the wheels 18 proceeding from the gear unit 3. In the present instance, the first output shaft 5 extends toward the left-hand side and the second output shaft 6 extends toward the right-hand side.

[0059] The integral differential 7 has a first planetary gearset P1 with a plurality of gearset elements and a second planetary gearset P2 which is operatively connected to the latter and which also has a plurality of gearset elements. In the present instance, at the first planetary gearset P1, the first gearset element is a first sun gear 25a, the second gearset element is a first planet carrier 26a, and the third gearset element is a first ring gear 27a. A plurality of first planet gears 28a in meshing engagement with the first sun gear 25a and the first ring gear 27a are rotatably arranged at the first planet carrier 26a. Further, at the second planetary gearset P2, the first gearset element is a second sun gear 25b, the second gearset element is a second planet carrier 26b, and the third gearset element is a second ring gear 27b. A plurality of second planet gears 28b in meshing engagement with the second sun gear 25b and the second ring gear 27b are rotatably arranged at the second planet carrier 26b.

[0060] The first planetary gearset P1 and the second planetary gearset P2 are formed, respectively, as negative planetary gearset, the first planetary gearset P1 being arranged radially inwardly of the second planetary gearset P2. Consequently, the integral differential 7 is constructed in a radially nested manner.

[0061] The first sun gear 25a of the first planetary gearset P1 is connected to the input shaft 4 to be fixed with respect to rotation relative to it. The first planet carrier 26a of the first planetary gearset P1 is connected to a flange 5b of the first output shaft 5 to be fixed with respect to rotation relative to it. The first output shaft 5 is connected to the flange 5b to be fixed with respect to rotation relative to it and extends axially through the input shaft 4, the first sun gear 25a and the rotor 20 of the drive unit 22 according to FIG. 2. Consequently, the first sun gear 25a is formed as an inner hollow toothed wheel and the input shaft 4 which is connected to the latter to be fixed with respect to rotation relative to it is constructed as a hollow shaft. The first ring gear 27a of the first planetary gearset P1 is connected to the second sun gear 25b of the second planetary gearset P2 to be fixed with respect to rotation relative to it via a coupling shaft 12. Consequently, the second sun gear 25b and the first ring gear 27a are formed integrally or monolithically. The second planet carrier 26b of the second planetary gearset P2 is arranged to be fixed with respect to the housing and secured to a stationary structural component 13. The second ring gear 27b of the second planetary gearset P2 is connected to the second output shaft 6 to be fixed with respect to rotation relative to it via an intermediate shaft 15 and a flange 6a. The output shafts 5, 6 are not shown in FIG. 3 and FIG. 5 but only in FIG. 1, FIG. 2 and FIG. 4. Only flanges 5b, 6a which are connected to the respective output shaft 5, 6 via an inner toothing 16 to be fixed with respect to relative rotation are shown in FIG. 3 and FIG. 5.

[0062] A first output torque is transmittable to the first output shaft 5 by the first planetary gearset P1. A reaction torque of the first planetary gearset P1 is transformable in the second planetary gearset P2 such that a second output torque corresponding to the first output torque is transmittable to the second output shaft 6.

[0063] In a pull operation of the powertrain 2, the power flow runs from the input shaft 4 at which the propulsion power of the drive unit 22 is introduced into the gear unit 3 to the two output shafts 5, 6 via the planetary gearsets P1, P2 of the integral differential 7. In a push operation of the powertrain 2, the power flow runs in the reverse direction from the respective output shaft 5, 6 via the planetary gearsets P1, P2 of the integral differential 7 to the input shaft 4, where the propulsion power is introduced into the drive unit 22. In push operation, the drive unit 22 can be operated in generator mode for generating electrical energy.

[0064] An actuation mechanism 8 having a plurality of claw-shaped positive engagement elements 9 is operatively arranged between the first output shaft 5 and the second output shaft 6, the claws or positive engagement elements 9 being formed to generate a co-rotationally fixed connection between the two output shafts 5, 6 when actuated. In this instance, the actuation mechanism 8 is an electromagnetic actuator comprising a magnet 10 which is arranged fixed with respect to the housing. In the present instance, the magnet 10 is slidingly mounted on the flange 6a of the second output shaft 6. Alternatively, the magnet 10 can also be slidingly mounted directly on the second output shaft 6 or fastened to a housing at a distance from the second output shaft 6 or the flange 6a of the second output shaft 6 so that a sliding support of the magnet 10 can be omitted.

[0065] The positive engagement elements 9 are connected to a common ring 9b having the shape of a circular disk. The positive connection elements 9 are fastened to the ring 9b via a driver 9c. Accordingly, together with the drivers 9c and the ring 9b, the positive engagement elements 9 form an integral component part which can be formed integrally or in multiple parts depending on the requirements of the component part. In every case, the individual portions or segments are connected to one another to be fixed with respect to relative rotation. To this end, the positive engagement elements 9 are supported, i.e., connected to be fixed with respect to relative rotation, in circumferential direction at the intermediate shaft 15 arranged between the second ring gear 27b and the second output shaft 6. The drivers 9c pass through the wall of the substantially radially extending portion of the intermediate shaft 15 at corresponding recesses, not shown, the drivers 9c being axially guided in the respective recess and supported in circumferential direction.

[0066] The integral component part is formed from a magnetic material in this embodiment example. Insofar as the actuation mechanism 8 is an electromechanical, hydraulic or pneumatic actuator in alternative embodiment forms which are likewise possible, the integral component part with the positive engagement elements 9 can also be formed from a different material. The actuation mechanism 8 is always formed in such a way that a positive engagement can be produced between the output shafts 5, 6 or between the flanges 5b, 6a when the actuation mechanism 8 is actuated.

[0067] In the present example, the actuation mechanism 8 in that the magnet 10 formed as electromagnet is energized and accordingly interacts with the ring 9b and the positive engagement elements 9 arranged at the latter so that the ring 9b and the positive engagement elements 9 are set in axial motion, specifically in direction of the first output shaft 5 and away from magnet 10. On a front side directed to the first output shaft 5, the positive engagement elements 9 have, in each instance, a first face toothing 9a which is adapted to come in meshing engagement with a second face toothing 5a at the flange 5b of the first output shaft 5 to form a positive engagement in circumferential direction between the output shafts 5, 6 when the actuation mechanism 8 is actuated, i.e., during the above-mentioned axial displacement of the positive engagement elements 9 in direction of the first output shaft 5. The output shafts 5, 6 are connected to one another to be fixed with respect to relative rotation as long as the magnet 10 is energized by holding current. In the present instance, the second face toothing 5a is formed at the flange 5b which is in turn connected to the first output shaft 5 shown in FIG. 2 and FIG. 4 to be fixed with respect to rotation relative to it. Alternatively, the second face toothing 5a can be formed directly on the first output shaft 5.

[0068] Further, the ring 9b is formed to interact with a sensor unit 14 in order to acquire the axial position of the ring 9b in the system. In particular, the axial position of the ring 9b relative to the magnet 10 and/or the second output shaft 6 can be determined by the sensor unit 14.

[0069] The actuation mechanism 8 has a reset mechanism 17 comprising a plurality of return springs 17a distributed at the circumference for returning the positive engagement elements 9 and the ring 9b to an initial position. The return springs 17a are arranged between the flange 5b of the first output shaft 5 and the positive engagement elements 9 and cause the positive engagement elements 9 and the ring 9b to return—in this case toward the right-hand side—to their initial position when an energization of the magnet 10 is terminated or when the magnet 10 is no longer energized.

[0070] It is explicitly noted that the association of the gearset elements with the elements of the respective planetary gearset P1, P2 can be switched in any desired manner. The respective connection of the gearset elements comprising sun gear, planet carrier and ring gear is carried out depending on the requirements for the transmission ratios, including mathematical signs. Instead of a negative planetary gearset, the respective planetary gearset P1, P2 can also always be a positive planetary gearset by switching the connection of planet carrier and ring gear and increasing the amount of the stationary gear ratio by one. The reverse is also possible in an analogous manner.

[0071] Further, it is conceivable for an additional step-up gear unit, which is not shown and which is formed, for example, as a planetary transmission with one or more planetary gearsets, to be arranged between the drive unit 22 and the gear unit 3 in order to increase the overall transmission ratio of the drive.

[0072] Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the devices illustrated, and in their operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.