In-Wheel Motor Balancing Using Integrated Imbalance Sensing
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Solution Overview
Problem
Conventional balancing machines are unable to effectively balance wheel assemblies with integrated in-wheel motors due to their unique bolt patterns and structural integration, necessitating additional adaptors that increase weight and space, while existing methods for in-wheel systems fail to accurately determine balance weights without specialized equipment.
Innovation Solution
Integrate an imbalance sensor and orientation sensor directly onto the stator of the in-wheel motor, utilizing the motor for balancing, and employing a control unit to measure and correct imbalances directly on the vehicle, allowing for precise balancing of the tire and wheel assembly including the motor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional balancing machines are used to balance wheel assemblies with integrated in-wheel motors, then balancing can be performed, but additional adaptors are required which increase weight and space
Solution Approach 1:
The in-wheel motor serves dual purposes: as the propulsion motor and as the balancing motor. The motor spins the wheel assembly during balancing operations, eliminating the need for external balancing machine adaptors. This self-service approach reduces unsprung mass by removing the adaptor components while maintaining balancing accuracy through the motor's integrated sensors and control system.
2Measurement precision
If conventional balancing machines are used to balance wheel assemblies with integrated in-wheel motors, then balancing can be performed, but additional adaptors are required which increase space requirements
Solution Approach 1:
The balancing function is merged with the in-wheel motor system. The motor's stator housing integrates the imbalance sensor and orientation sensor, combining the propulsion and balancing functions into a single integrated unit. This eliminates the need for separate balancing machine adaptors, thereby reducing space requirements while maintaining balancing accuracy through the integrated sensor system.
3Use of energy by moving object
If in-wheel motors are integrated into the wheel assembly, then vehicle efficiency is improved, but unsprung mass increases necessitating more intricate suspension systems
Solution Approach 1:
The in-wheel motor performs dual functions as both the propulsion motor and the balancing motor. By using the motor itself to spin the wheel assembly during balancing operations, the system eliminates the need for external balancing equipment and adaptors. This reduces the overall added weight from in-wheel motor integration, thereby lessening the burden on the suspension system while maintaining the energy efficiency benefits of direct-drive in-wheel motors.
4Ease of operation
If sensors are permanently mounted on the stator and wheel assembly, then on-board balancing is enabled, but device complexity increases
Solution Approach 1:
The imbalance sensor is permanently mounted on the stator housing and the orientation sensor is permanently mounted on the wheel assembly, merging the balancing measurement functions into the existing motor structure. This integration enables on-board balancing capability while minimizing additional complexity by utilizing the motor's existing housing and mounting points rather than requiring separate balancing equipment.
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
Enables on-board balancing of the tire and wheel assembly with the in-wheel motor, reducing unsprung mass and eliminating the need for additional adaptors, thereby optimizing vehicle performance and simplifying the balancing process.
Implementation Method 1
On the stator electrical coils generate a rotating electro-magnetic field, while the rotor has a number of permanent magnets. The interaction between the rotating electro-magnetic field and the permanent magnets exert a torque on the rotor, resulting in a rotation of the wheel assembly.
Implementation Method 2
the imbalance sensor and orientation sensor permanently mounted on the wheel assembly or the stator, the imbalance sensor being used to measure an imbalance of the wheel assembly
Data Source
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AI summary
The invention relates to a method of balancing a wheel assembly of an electric car, in which the wheel assembly comprises an in-wheel motor. The wheel assembly (with the tire mounted on it) is spun by the in-wheel motor, the imbalance is measured by a sensor on the wheel and the angular orientation is determined by an orientation sensor. A control unit in the car then determines the position and weight needed for balancing the wheel.