Wheel-Side Resolver Mounting for Precise Rotor Angle Alignment
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Solution Overview
Problem
Existing wheel designs with integrated resolvers face challenges in maintaining precise angular position alignment between the resolver and electric motor due to play and tolerances, especially when the resolver is installed separately, leading to reliability issues in detecting the angular position of the rotor.
Innovation Solution
A wheel side design featuring a separately mounted resolver with a form-fitting element that engages in holes on both the rotating part and rotor, ensuring a defined angular position without the need for complex calibration, using fastening means and positive locking elements like dowel pins to stabilize the connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the resolver is designed separately from the electric motor and indirectly connected via the drive shaft, then the wheel side structure becomes more modular and maintenance becomes easier, but the angular position alignment precision deteriorates due to play and tolerances in connecting elements
Solution Approach 1:
A form-fitting connection element (dowel pin) is introduced as an intermediary between the resolver and the drive shaft to eliminate play and ensure precise angular position transmission. This mediator component fits into corresponding holes in both the resolver and drive shaft, creating a rigid connection that maintains measurement precision while preserving modular design benefits
Solution Approach 2:
The system is segmented into modular components (electric motor, drive shaft, resolver) that can be independently assembled and maintained, while the form-fitting connection ensures precise alignment between segments. This segmentation enables easier maintenance while the precise connection method resolves the alignment precision issue
2Measurement precision
If the resolver is permanently integrated into the electric motor, then angular position detection precision is improved through stable alignment, but maintenance accessibility and component replaceability worsen
Solution Approach 1:
The resolver is segmented from the electric motor as a separate replaceable component while maintaining precise alignment through the form-fitting connection to the drive shaft. This allows the resolver to be independently removed and replaced during maintenance while preserving angular position detection precision
Solution Approach 2:
The form-fitting connection is designed in advance to ensure precise angular position alignment when the resolver is installed. The predetermined hole positions and dowel pin configuration automatically establish the correct alignment, eliminating the need for complex calibration procedures during assembly or maintenance
3Volume of moving object
If the resolver is indirectly connected to the electric motor via the drive shaft, then space constraints are better accommodated and component accessibility is improved, but reliability in detecting angular position deteriorates due to potential play and tolerances
Solution Approach 1:
The form-fitting connection element acts as a mediator that eliminates play and ensures reliable angular position transmission from the drive shaft to the resolver. This intermediate component creates a rigid mechanical link that maintains detection reliability while preserving the benefits of indirect connection for space utilization
Solution Approach 2:
The form-fitting connection uses precisely machined cylindrical holes and a corresponding dowel pin to create a rigid, play-free connection. The geometric precision of these curved surfaces ensures reliable angular position transmission without the tolerances that would otherwise compromise detection reliability
Data Source
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AI summary
A wheel assembly comprises: an electric motor, which includes a stator and a rotor; a drive shaft, which is connected to the rotor for common rotation about a drive axis, so that drive power generated by the electric motor can be transmitted via the drive shaft to other components of the wheel assembly; and a resolver for detecting the angular position of the rotor, wherein the resolver comprises a stationary part and a rotating part, and the rotating part of the resolver is connected to the rotor of the electric motor for common rotation about the drive axis. The resolver is designed separately from the electric motor. Furthermore, the wheel assembly has a positive-locking element, which is arranged eccentrically with respect to the drive axis and engages positively in a hole formed on the rotating part and in a hole formed on the rotor to ensure a defined angular position of the rotating part relative to the rotor.