Rear Axle Drive Device Torque Vectoring
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Solution Overview
Problem
Existing drive devices for electrically driven vehicle axles lack the capability to provide enhanced driving dynamics and functional extension with minimal installation space, particularly in supporting torque redistribution during cornering.
Innovation Solution
A drive device with two electric machines per rear axle, where each machine's shaft is connected via a switching element and transmission stage to a stub shaft, allowing for torque distribution through an axle differential, enabling both wheel-selective and differential drive modes, and incorporating load-shiftable shifting elements and multi-plate clutches for efficient torque management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two electric motors are installed on the rear axle with switching elements and transmission stages, then torque redistribution capability is improved, but device complexity increases
Solution Approach 1:
The drive device is designed to operate in multiple modes (wheel-selective drive and differential drive) using the same components. The switching elements can connect each electric motor to either its dedicated flange shaft or to the axle differential, allowing the system to adapt its function based on driving conditions without requiring separate dedicated systems for each mode.
Solution Approach 2:
The drive device is divided into independent modules: two electric motors, two switching elements, two transmission stages, and an axle differential. Each electric motor with its switching element and transmission stage forms an independent drive unit that can operate autonomously or in coordination with the other, allowing flexible torque distribution and simplifying the overall system architecture.
2Adaptability or versatility
If switching elements and transmission stages are added for torque vectoring, then driving dynamics are improved, but installation space requirement increases
Solution Approach 1:
The patent utilizes the longitudinal dimension of the vehicle by arranging the electric motors and transmission components along the length of the axle rather than only in the transverse direction. This dimensional arrangement allows for compact packaging of the switching elements and transmission stages within the available space, accommodating the enhanced driving dynamics capabilities without excessive space consumption.
3Ease of operation
If wheel-selective drive mode is implemented with open third and fourth switching elements, then torque distribution control is improved, but mechanical connection complexity increases
Solution Approach 1:
The switching elements are designed to be dynamically controllable, allowing the system to transition between different connection states based on driving conditions. In wheel-selective drive mode, the third and fourth switching elements are opened to create direct mechanical connections, while in differential drive mode, they are closed to engage the axle differential. This dynamic switching capability provides flexible torque distribution control while maintaining relatively simple mechanical connections in each operational state.
Data Source
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AI summary
The invention relates to a drive device for a vehicle axle, in particular a rear axle (HA), of a two-track vehicle with an electric drive, wherein an electric machine (EM1, EM2) is associated with every vehicle wheel (15) of the vehicle axle (HA), the electric machine shafts (19, 21) of which electric machine can be drivingly connected, by means of a first and a second shifting element (SE1, SE2), to a first and a second flange shaft (11, 13) of the vehicle wheels (15), and wherein in a first transmission gear (I), the first and the second shifting element (SE1, SE2) are shifted and the electric machine shafts (19, 21) output directly to the flange shafts (11, 13) of the vehicle wheels (15) via the first and the second shifting element (SE1, SE2). According to the invention, the vehicle axle (HA) has a transverse differential (17) which, on the output side, outputs to the flange shafts (11, 13) of the vehicle wheels (15) and, on the input side, can be drivingly connected to the electric machine shafts (19, 21) by means of a third and a fourth shifting element (SE3, SE4). In a second transmission gear (II), the third and the fourth shifting element (SE3, SE4) are closed, while the first and/or second electric machine shaft (19, 21) output to the flange shaft (11, 13) via the third and/or fourth shifting element (SE3, SE4) and the transverse differential (17).