In-Wheel Motor Hub-Rotor Spline Assembly for Backlash-Free Torque
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Solution Overview
Problem
In-wheel motors face challenges with backlash between the rotor and shaft, requiring complex structures for support and assembly, which increase weight, cost, and complicate maintenance, especially when integrated into a vehicle's wheel hub.
Innovation Solution
An in-wheel motor design featuring a hub with a neck portion and flange portion that engages with a rotor through face splines, a stator supported by a casing, and a bolt securing the hub to the rotor, eliminating backlash and simplifying assembly and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a complex support structure is used to eliminate backlash between rotor and shaft, then reliability improves, but device complexity increases
Solution Approach 1:
The hub and rotor are merged into a unitary body, eliminating the need for separate support structures and backlash elimination mechanisms. This integration directly resolves the contradiction by achieving both reliability (no backlash) and simplicity (single piece construction) simultaneously.
2Adaptability or versatility
If the motor structure is compacted into limited wheel hub space, then adaptability improves, but ease of manufacture deteriorates
Solution Approach 1:
The hub and rotor are combined into a single unitary body, which simplifies manufacturing compared to assembling multiple separate components in a compact space. This merging approach maintains adaptability for wheel hub integration while improving ease of manufacture through reduced assembly steps.
3Power
If traditional power transmission system is used, then power transmission capability is ensured, but weight increases
Solution Approach 1:
The invention extracts and eliminates the traditional power transmission system (gears, joints, bearings) from the vehicle drivetrain by directly coupling the motor rotor to the wheel hub through the unitary hub-rotor structure. This extraction maintains full torque transmission capability while dramatically reducing the weight of the power transmission system.
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
The design achieves backlash-free torque transmission, reduces weight, and simplifies assembly and maintenance, while allowing integration into a vehicle's wheel hub without a heavy power transmission system.
Implementation Method 1
a stator including an electromagnet for generating a magnetic flux
Implementation Method 2
a stator including an electromagnet for generating a magnetic flux and fixedly supported by the casing; a rotor rotatably supported by the casing and disposed coaxially with the hub, the rotor including a shoulder portion having a second face spline to mesh with the first face spline, and a disk portion formed in a unitary body with the shoulder portion and radially expanding from the shoulder portion toward the stator to receive the magnetic flux so as to be driven around the axis
Data Source
AI summary
An in-wheel motor includes a casing at least partly housed in a wheel; a hub rotatable about an axis with a neck portion disposed in the casing and having a first face spline and a flange portion radially expanding outside the casing to combine with the wheel; a stator including an electromagnet for generating a magnetic flux and fixedly supported by the casing; a rotor rotatably supported by the casing and including a shoulder portion having a second face spline to mesh with the first face spline and a disk portion integral with the shoulder portion and radially expanding from the shoulder portion toward the stator to receive the magnetic flux so as to be driven around the axis; and a bolt screwed in the shoulder portion to force the first face spline in close contact with the second face spline.