Compact Handwheel Actuator With Nested Planetary Gear Assembly
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Solution Overview
Problem
As the automotive industry advances towards autonomous driving, the need for a reduced steering system size arises to maximize cabin space for comfort and functionality, as manual steering wheel manipulation may not be required at all times.
Innovation Solution
A handwheel actuator assembly featuring a motor with a planetary gear assembly and an electronic control unit, which includes a handwheel shaft for directional control, allowing for compact design and integration within the EPS system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a traditional steering system is used, then manual steering capability is maintained, but the steering system occupies excessive cabin space
Solution Approach 1:
The planetary gear assembly is nested within the motor housing, with the sun gear positioned in the center, planet gears orbiting around it, and the ring gear enclosing the entire planetary mechanism. This nested configuration allows the gear train to be compactly integrated within the motor's radial and axial space, dramatically reducing the overall steering actuator volume while maintaining full manual steering capability through the handwheel shaft connection
2Volume of moving object
If the steering system size is reduced, then cabin space is increased, but the complexity of the steering actuator increases
Solution Approach 1:
The motor and planetary gear assembly are merged into a single integrated housing structure, where the gear train is contained within the motor's radial and axial envelope. The handwheel shaft is directly coupled to the sun gear, eliminating the need for separate coupling mechanisms. This merging of components into a unified actuator assembly reduces overall complexity despite the sophisticated internal gear arrangement
Solution Approach 2:
The motor serves multiple functions: it provides powered steering assistance through the planetary gear train while also allowing manual override capability through direct handwheel shaft connection. The planetary gear assembly simultaneously provides torque multiplication for power assistance and mechanical advantage for manual steering. This multi-functionality reduces the need for separate components, simplifying the overall system architecture
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 compact handwheel actuator assembly enhances vehicle cabin space utilization while maintaining operational efficiency and comfort by reducing the overall size of the steering system.
Implementation Method 1
a planetary gear assembly disposed within the motor
Data Source
AI summary
A handwheel actuator assembly includes a handwheel shaft configured for connection to a handwheel, the handwheel shaft extending longitudinally about an axis. The handwheel actuator assembly also includes a motor operatively coupled to the handwheel shaft. The handwheel actuator assembly further includes a planetary gear assembly disposed within the motor. The handwheel actuator assembly yet further includes an electronic control unit (ECU) in operative communication with the motor.