Hypoid Steering Torque Feedback Assembly for Backlash Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing steer-by-wire systems in autonomous vehicles face issues with gear rattle due to torque and direction reversals, requiring precise backlash control and additional gearing for effective torque feedback, which increases size and cost.
Innovation Solution
A steering torque feedback assembly using a hypoid gear assembly with two electric motors, where the motors' output shafts are connected via hypoid pinion gears to a crown wheel, allowing for compact design and reduced gearing needs, enabling torque application in opposite or same directions to manage backlash and provide road feel without precision components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If additional gearing is used to achieve large gear ratio reduction, then torque feedback capability is improved, but device complexity and size increase
Solution Approach 1:
The patent combines multiple gear ratio reductions into a single hypoid gear stage, merging what would traditionally require multiple gear sets into one integrated component. This achieves the required torque multiplication while reducing the number of separate gearing components and simplifying the overall transmission architecture.
Solution Approach 2:
The hypoid gear arrangement allows the input and output shafts to be non-intersecting and offset from each other, utilizing three-dimensional spatial arrangement rather than simple planar gear stages. This enables compact packaging of the steering column assembly while achieving the necessary gear ratio reduction.
2Manufacturing precision
If precision components are used to control backlash, then torque feedback precision is improved, but manufacturing cost and device complexity increase
Solution Approach 1:
The system uses two electric motors that can dynamically adjust their torque output to compensate for backlash. By actively controlling the motors in opposite directions when needed, the system maintains precise torque feedback without requiring mechanically pre-loaded or precision-adjusted gear components.
Solution Approach 2:
The dual motor arrangement with independent control enables feedback-based backlash compensation. The system can detect and correct for gear play by adjusting motor torques in real-time, eliminating the need for precision mechanical components while maintaining accurate torque feedback.
3Device complexity
If two electric motors are used to eliminate backlash control needs, then device complexity is reduced, but power consumption and control complexity increase
Solution Approach 1:
The two motors operate in alternating or coordinated periodic cycles to manage backlash. Rather than both motors running continuously at full power, they engage in coordinated sequences where one motor may be active while the other compensates, reducing overall energy consumption while maintaining backlash elimination.
4Volume of moving object
If hypoid gear assembly is used for compact design, then volume is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The hypoid gear assembly merges the steering column's torque multiplication and directional change functions into a single integrated gear stage. This consolidation achieves compact dimensions while the active dual-motor control system compensates for any manufacturing tolerances, reducing the stringency of precision requirements.
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
This solution reduces gear rattle and size/cost by enabling efficient torque feedback and backlash management, allowing for a compact, cost-effective assembly that adapts to both autonomous and manual driving modes.
Implementation Method 1
The output shaft of each of the first and second motors includes a hypoid pinion gear engaged with the hypoid crown wheel
Implementation Method 2
The provision of two electric motors also allows the motor to be controlled in a first operational mode to apply torque in opposite directions to the crown wheel
Implementation Method 3
the aperture comprises means for a keyed connection with a complementarily-shaped portion of a steering column
Data Source
AI summary
A steering torque feedback assembly for a vehicle steering column includes a housing, a crown wheel of a hypoid gear assembly rotatably mounted in the housing and being configured to rotate with, or being connected to, a vehicle steering column, and first and second electric motors within the housing, each having a rotatable output shaft, wherein the output shaft of each of the first and second motors comprises a hypoid pinion gear engaged with the hypoid crown wheel.