In-Wheel Motor Sensor Sealing Against Bracket Deformation
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Solution Overview
Problem
In existing in-wheel motors, external forces from vibrations or shocks can cause the bracket to deform, leading to a gap between the bracket and the oil seal, allowing water and dust to intrude and adhere to the rotation angle sensor.
Innovation Solution
The in-wheel motor design includes a tubular bracket part extending in the vehicle width direction, with a stator connected to the bracket, a rotor connected to the wheel, and a bearing to support the shaft. A rotation angle sensor is mounted with a rotor-side sensor part on the shaft and a bracket-side sensor part on the inner circumferential surface of the bracket. A seal cover is provided to block the space between the bracket opening and the sensors, preventing water and dust from adhering to them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an oil seal is provided between the rotor and bracket to prevent water and dust intrusion, then sealing performance is improved, but the bracket may deform due to external forces causing gaps that allow water and dust to intrude
Solution Approach 1:
A seal cover is introduced as an intermediary component between the bracket and the oil seal. The seal cover includes a seal surface that contacts the oil seal, positioning the oil seal at a location away from the bracket. This intermediary structure allows the oil seal to maintain effective sealing without being directly affected by bracket deformation from external forces.
2Measurement precision
If the rotation angle sensor is arranged on the radially outer side of the hub bearing to detect rotor rotation angle, then measurement function is improved, but water and dust can adhere to the sensor through gaps caused by bracket deformation
Solution Approach 1:
The seal cover acts as a protective intermediary that creates a sealed space around the rotation angle sensor. The seal surface of the cover positions the oil seal away from the bracket, and the cover itself forms a barrier that prevents water and dust from reaching the sensor, thus protecting the measurement component while maintaining its detection function.
Solution Approach 2:
The oil seal, positioned by the seal cover, creates a hermetic barrier using sealing principles similar to pneumatic and hydraulic sealing systems. This sealing mechanism prevents the intrusion of water and dust into the sensor area, protecting the measurement system from harmful environmental factors.
3Strength
If the bracket is fixed to the vehicle body to support the motor components, then structural stability is improved, but vibration and shock from the road surface cause deformation and gap formation
Solution Approach 1:
The seal cover serves as a mediator between the bracket and the sealing system. It absorbs and isolates the effects of vibration and shock forces, allowing the bracket to remain firmly fixed for structural stability while the seal cover and oil seal combination maintains effective sealing despite dynamic forces from road surface vibrations.
Data Source
AI summary
An in-wheel motor includes a bracket part, a stator connected to the bracket part, a rotor having a shaft and a field pole and connected to a wheel, a bearing rotatably supporting the shaft, and a rotation angle sensor. The shaft extends to a position facing an inner circumferential surface of the bracket part in a radial direction of the shaft. The rotation angle sensor has a rotor-side sensor part mounted to the shaft at the position facing the inner circumferential surface of the bracket part in the radial direction, and a bracket-side sensor part configured to output a signal that depends on rotation angle of the rotor-side sensor part. The in-wheel motor further includes a seal cover that blocks a space between an opening of the bracket part and the rotor-side sensor part and the bracket-side sensor part.