Axle Assembly Single Motor Torque Distribution
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Solution Overview
Problem
Existing drive concepts for electric and hybrid vehicles are inefficient in terms of cost and weight due to the need for multiple wheel hub motors and complex transmission systems, particularly in two-wheel axle configurations.
Innovation Solution
An axle assembly with a single wheel hub motor driving both wheels via a mechanical transmission mechanism, including a transmission shaft unit offset from the wheel shafts, allowing for efficient torque transmission and reduction or increase, and eliminating the need for a second wheel hub motor, thus reducing mass and production costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If both wheels are equipped with individual wheel hub motors, then independent rotational speed and torque control at both wheels is achieved, but vehicle mass and production costs increase
Solution Approach 1:
The patent merges the drive functions of both wheels into a single wheel hub motor located in one wheel. The motor shaft is connected to the axle shaft via a differential mechanism, allowing one motor to drive both wheels independently through the differential's ability to distribute torque differently to each wheel, thus reducing vehicle mass while maintaining independent wheel control capability
Solution Approach 2:
The single wheel hub motor is designed to perform multiple functions: it provides drive force to one wheel directly, and through the differential mechanism, it also provides drive force to the other wheel. The differential mechanism itself serves multiple functions by enabling both torque distribution and independent wheel rotation, making the overall system more versatile with fewer components
2Weight of moving object
If a single wheel hub motor drives one wheel directly and the other wheel via axle shaft, then vehicle mass is reduced compared to dual motors, but transmission components are still required
Solution Approach 1:
The patent combines the functions of the wheel hub motor, differential, and axle shaft into an integrated drive system. The motor shaft is directly coupled to the differential input, and the differential output connects to both wheels, merging multiple transmission functions into a compact arrangement that reduces overall system complexity while maintaining the ability to drive both wheels from one motor
Solution Approach 2:
The differential mechanism is nested within the wheel hub assembly, with the motor shaft connected to the differential input and the differential outputs connected to both wheels. This nested arrangement allows the transmission components to be compactly integrated, reducing the space and complexity required for the drivetrain system
3Force
If traditional transmission components are used for torque transmission, then torque can be transmitted and modified, but the system becomes more complex and heavier
Solution Approach 1:
The patent replaces complex mechanical transmission systems (such as gear differentials with multiple moving parts) with a simpler differential mechanism that directly couples the motor shaft to the wheel shafts. This substitution maintains the essential function of torque distribution and modification while significantly reducing mechanical complexity and component count
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enables a low-cost, weight-saving drive system for electric or hybrid vehicles by using a single wheel hub motor to drive both wheels, optimizing the vehicle's mass and production costs while maintaining efficient torque transmission.
Implementation Method 1
a first wheel (2a) which is connected in a rotationally fixed manner to a first wheel shaft (3a) with a wheel hub motor (7)
Implementation Method 2
a mechanical transmission mechanism (9) for the transmission of a drive force or a drive torque from the wheel hub motor (7) to the second wheel (2b)
Data Source
AI summary
An axle assembly includes a first wheel connected in a rotationally fixed manner to a first wheel shaft with a wheel hub motor and a second wheel connected in a rotationally fixed manner to a second wheel shaft. The second wheel is coupled by a mechanical transmission mechanism in a driving manner to the wheel hub motor. The transmission mechanism has a transmission shaft unit which extends generally parallel to, but non-coaxially with the wheel shafts such that the transmission shaft unit is offset in the vehicle longitudinal direction from the wheel shafts and is coupled via coupling units in a force-transmitting manner on one hand to the wheel hub motor and on the other hand to the second wheel to provide drive force to both wheels from a single wheel hub motor at least partially containing within one of the wheel hubs.