HYBRID REAR AXLE DRIVE

Abstract

A hybridized rear axle drive (H-RAD) includes an electrical torque vectoring system (eTV) and a drive train for a motor vehicle, especially a plug-in hybrid vehicle (PHEV), and is configured to perform a method for electric torque distribution (electric torque vectoring).

Claims

1. A rear axle drive for a motor vehicle, comprising: a pinion shaft, a hollow shaft having bevel and spur gear toothing, and a differential having a spur gear firmly attached to a casing of the differential, wherein the pinion shaft is connected to a Cardan shaft of the motor vehicle and the pinion of the pinion shaft engages with the bevel toothing of the hollow shaft and the spur gear toothing of the hollow shaft engages with the toothing of the spur gear of the differential.

2. The rear axle drive according to claim 1, wherein the differential has a connection to a transmission gearing of an electric traction motor.

3. The rear axle drive according to claim 1, wherein a connecting shaft is led through the hollow shaft, comprising a spur gear which is part of a transmission gearing.

4. The rear axle drive according to claim 3, wherein the transmission gearing is linked to an overlay unit, having a linkage to an output shaft of the differential.

5. The rear axle drive according to claim 4, wherein the overlay unit comprises a two-row planetary gearing having a freewheeling single-piece ring gear for both sets of planetary gears.

6. The rear axle drive according to claim 5, wherein the two-row planetary gearing comprises first planet gears and planet carriers with linkage to the casing of the differential, a first sun gear with linkage to the transmission gearing, second planet gears and planet carriers with linkage to one of the output shafts and a casing-fixed second sun gear.

7. A drive train for a plug-in hybrid vehicle, comprising: a combustion engine, at least one electric traction motor, and a rear axle drive according to claim 1.

8. The drive train according to claim 7, wherein an electric traction motor is linked to the differential across a transmission gearing.

9. The drive train according to claim 7, wherein a drive module comprising an electric motor and a power electronics is linked to the differential across a connecting shaft, a transmission gearing and an overlay unit.

10. A method for torque distribution between two output shafts of a rear axle of a motor vehicle, comprising: producing, by a drive module through a transmission gearing and an overlay unit having a two-row planetary gear box, comprising first planet gears and planet carriers with linkage to the casing of a differential, a first sun gear with linkage to the transmission gearing, second planet gears and planet carriers with linkage to one of the output shafts and a casing-fixed second sun gear, an acceleration or deceleration of an output shaft connected to the second planet carrier of the overlay unit.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0021] Embodiments are presented schematically with the aid of the drawing and shall be further described with reference to the drawing.

[0022] FIG. 1 shows a schematic representation of one embodiment of a hybrid rear axle drive (H-RAD) with electronic torque vectoring (eTV).

DETAILED DESCRIPTION

[0023] FIG. 1 shows a schematic representation of one embodiment of the hybrid rear axle drive (H-RAD) with electronic torque vectoring (eTV).

[0024] A pinion shaft 1 is the interface with the Cardan shaft in the vehicle. A bevel/spur gear shaft 2 with drive-through to an eTV module 6 is a transversely situated hollow shaft with bevel and spur gear toothing having drive-through for a connecting shaft 2a from the eTV drive module 6 to an eTV transmission gearing 7. A differential 3 with spur gear comprises a differential casing with firmly attached spur gear, a linkage to an eTV overlay unit 8 and to the transmission gearing 5 of an electric traction motor 4. The equalizing of rotary speeds occurs by a design as a bevel gear differential. An electric traction motor 4 is permanently connected to a transmission gearing 5. The transmission gearing 5 of the electric traction motor 4 comprises a planetary gearing and is permanently connected to the casing of the differential 3. The planetary gearing is designed such that the sun gear is linked to the drive shaft of the electric traction motor 4, the planet gears and planet carriers produce the linkage to the casing of the differential 3, and the ring gear casing is firmly attached. A drive module 6 for the electric torque vectoring comprises an electric motor with integrated power electronics. A form-fitted connection to the eTV transmission gearing 7 exists by means of splines. The eTV transmission gearing 7 has various spur gear stages. The eTV overlay unit 8 comprises a 2-row planetary gearing with a freewheeling single-piece ring gear 8a for both sets of planet gears and right-side planet carriers 8b with linkage to the casing of the differential 3, a right-side sun gear 8c with linkage to the eTV drive module 6 across the eTV transmission gearing 7, left-side planet gears and planet carriers 8d with linkage to a left output shaft 9a, and a left-side sun gear 8e, which is firmly attached to the casing. The left-side output shaft 9a and the right-side output shaft 9b form the interfaces with the Cardan shafts in the vehicle.

[0025] During the electric torque vectoring (eTV), the eTV drive module 6 brings about a specific redistribution of the drive torques between the wheels, depending on the direction of turning, in concert with the eTV overlay unit 8. The increasing or reducing of the particular wheel torque occurs here in alternation and to the same degree of magnitude. The eTV drive module 6 drives the right sun gear 8c of the overlay unit 8 across the eTV transmission gearing 7. The sun gear 8c drives the ring gear 8a across the right planet gear set 8b and the left planet gear set 8d. In this way, depending on the direction of turning of the eTV drive module 6, an accelerating or a decelerating of the left planet carrier 8d and the linked left output shaft 9a will occur. The right output shaft 9b will be accelerated or decelerated in the same degree and oppositely in direction via the bevel toothing of the differential 3.

[0026] German patent application no. 10 2021 132321.5, filed Dec. 8, 2021, to which this application claims priority, is hereby incorporated herein by reference in its entirety.

[0027] Aspects of the various embodiments described above can be combined to provide further embodiments. In general, in the following claims, the terms used should not be construed to limit the claims to the specific embodiments disclosed in the specification and the claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which such claims are entitled.