Steering Assist Worm Gear Lock With Wedge Breakaway Torque
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing steering assist system lock mechanisms are bulky, heavy, and complex, requiring significant packaging space and assembly effort, with limited efficiency in resisting torque and handling ingress/egress loads.
Innovation Solution
A lock mechanism featuring a wedge-shaped lock feature moveable into and out of engagement with a worm gear's teeth, utilizing a spring-loaded slide assembly within a housing, allowing for adjustable 'breakaway' torque resistance and reduced complexity and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional lock mechanism with inner hub, lock sleeve ring, grease and outer shaft lock sleeve is used, then the lock can resist torque and prevent movement, but the mechanism becomes bulky, heavy, and complex with significant mass and packaging space requirements
Solution Approach 1:
The patent extracts the essential locking function from the complex traditional mechanism and implements it through a simplified pin-and-slot system. The lock pin with cam surface and corresponding slot geometry provide torque resistance through geometric constraint rather than through multiple precision components working together, thereby reducing device complexity while maintaining reliability.
Solution Approach 2:
Instead of using a sleeve that resists torque through friction and compression (traditional approach), the patent inverts the approach by using a pin that actively engages with a slot through geometric interlocking. The lock pin's cam surface pushes against the slot wall to resist torque, reversing the traditional sleeve-based resistance mechanism.
2Reliability
If a traditional lock mechanism with multiple precision components is used, then the lock can maintain engagement under load, but the mechanism requires significant packaging space and axial space on the output shaft
Solution Approach 1:
The patent extracts only the essential elements needed for reliable engagement (lock pin, slot, cam surface) and eliminates unnecessary components. This minimalistic approach reduces packaging space while maintaining engagement stability through the efficient geometric design of the pin-slot interaction.
Solution Approach 2:
The patent utilizes the radial dimension of the output shaft rather than requiring additional axial space. The lock pin extends radially from the output shaft and engages with the slot in the drive gear, converting an axial space requirement into a radial arrangement that saves packaging space.
3Reliability
If a traditional lock mechanism with compression assembly is used, then the lock can resist torque through breakaway torque, but the mechanism requires press operations for assembly and has significant mass
Solution Approach 1:
The patent removes the compression assembly, grease, and multiple press operations from the manufacturing process. The lock pin is simply inserted into the output shaft and engages with the slot through geometric constraint, eliminating complex assembly steps while maintaining torque resistance through the cam surface geometry.
Solution Approach 2:
The lock mechanism is designed to be self-aligning and self-locking through the cam surface and slot geometry. The components automatically engage in the correct position without requiring precision press operations or assembly grease, allowing for easier manual or automated assembly.
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 solution provides a compact, lightweight, and cost-effective lock mechanism that effectively resists torque and handles ingress/egress loads, enabling a smaller motor size for steer-by-wire systems while maintaining adequate resistance and reducing assembly costs.
Implementation Method 1
a spring-loaded slide assembly within a housing
Implementation Method 2
spring-loaded slide assembly
Implementation Method 3
a wedge shaped lock feature moveable into and out of engagement with a set of teeth of a worm gear
Implementation Method 4
wedge shaped lock feature
Implementation Method 5
worm gear having a first set of teeth and a second set of teeth, the first set of teeth in meshed engagement with the worm
Data Source
AI summary
A steering assist system of a steering column assembly is provided. The system includes a worm rotatably driven by an actuator. The system also includes a worm gear having a first set of teeth and a second set of teeth, the first set of teeth in meshed engagement with the worm, the worm gear operatively coupled to a steering shaft. The system further includes a lock feature moveable into and out of engagement with the second set of teeth of the worm gear to define a locked condition and an unlocked condition of the worm gear.