In-Wheel Motor Flexible Sensor Coupling
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Solution Overview
Problem
Prior art in-wheel electric motors face complex alignment issues and misalignment due to shocks and vibrations, affecting the accuracy of position sensors installed inside the motor, which complicates installation and operation.
Innovation Solution
The design features a cylindrical rotor with a coaxial opening for the power electronics device and an angular position sensor mounted on a flexible pivoting axis, allowing for easier installation and alignment, with the sensor accessible from the road side, and a flexible joint to accommodate small misalignments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the position sensor is installed inside the motor, then the motor structure is compact, but the alignment complexity increases due to complex alignment operations required
Solution Approach 1:
A flexible coupling is introduced as an intermediary element between the position sensor and the rotor. This coupling accommodates alignment deviations caused by shocks and vibrations, serving as a mediator that absorbs misalignment without requiring complex alignment operations during installation.
Solution Approach 2:
The patent changes the rigidity parameter of the connection between the position sensor and the rotor by using a flexible coupling instead of a rigid connection. This allows the system to adapt to alignment variations while maintaining the compact internal sensor installation.
2Volume of moving object
If the position sensor is installed inside the motor, then the motor structure is compact, but the measurement precision deteriorates due to misalignment from shocks and vibrations
Solution Approach 1:
The flexible coupling is installed beforehand to cushion and absorb the effects of shocks and vibrations before they can cause misalignment between the position sensor and the rotor. This protective measure ensures continuous accurate measurement despite external disturbances.
Solution Approach 2:
The flexible coupling acts as a mediator that isolates the position sensor from vibrational disturbances while transmitting the necessary rotational motion, thereby preserving measurement precision in the compact internal installation configuration.
3Loss of energy
If the power electronics are integrated within the stator, then the electrical losses are minimized, but the installation and maintenance difficulty increases
Solution Approach 1:
The power electronics are segmented into a separate removable module rather than being permanently integrated into the stator. This modular design allows the power electronics to be electrically connected to the stator windings while physically separable, enabling easy replacement and maintenance without affecting the motor structure.
Solution Approach 2:
The modular power electronics can be easily removed, replaced, or recovered when needed, allowing maintenance personnel to swap out electronic components without disassembling the entire motor, thus combining the electrical efficiency of integration with the maintenance benefits of separability.
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
Facilitates simpler and more accurate installation of the power electronics and position sensor, reducing the impact of assembly inaccuracies and vibrations on motor performance.
Implementation Method 1
power electronics that are situated within the stator, which power electronics convert electrical energy from a power supply system of the vehicle, e.g. a battery pack and/or an electric generator, to an AC current that is suitable for use by the electric motor
Implementation Method 2
a detector for an angular position of the rotor body relative to the stator; the detector for the angular position comprising an angular position sensor
Implementation Method 3
a flexible joint to accommodate small misalignments
Data Source
AI summary
An in-wheel electric motor includes at a vehicle side a connector stub, a stator body connected to the connector stub and on an outer surface equipped with stator windings, and further includes a rotor body coaxially enclosing the stator and rotatable around a rotation axis. The electric motor further includes a power electronics device for powering the stator and a detector for an angular position of the rotor body relative to the stator. The connector stub is provided with a support for coupling to the power electronics device which is mounted on the support inside the hollow stator body. The detector includes an angular position sensor mounted inside the hollow stator body and coupled to the rotor body wherein the detector is mounted on the power electronics device coaxially with the rotation axis.