Worm Gear Clearance Compensator for Electric Power Steering
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electric power steering systems experience increased backlash and rattle noise due to wear in the worm gear teeth, leading to clearance issues between the worm wheel and worm gear, which affects steering stability and smoothness.
Innovation Solution
An electric power steering system incorporating a worm gear clearance compensator, featuring a housing, steering shaft, worm wheel, worm shaft, motor, and an elastic member formed by a double-folding leaf spring to apply a load to the worm shaft bearing, ensuring continuous meshing without clearance even when the worm gear is worn down.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the worm gear and worm wheel mesh tightly initially, then steering precision is good, but clearance increases and backlash occurs after wear
Solution Approach 1:
The patent applies the dynamics principle by making the worm shaft position adjustable through the elastic member (leaf spring). The leaf spring allows the worm shaft to dynamically adjust its position based on wear conditions, maintaining optimal meshing clearance between the worm gear and worm wheel throughout the service life, thereby resolving the contradiction between initial precision and long-term reliability
Solution Approach 2:
The patent implements parameter changes by modifying the radial position of the worm shaft relative to the worm wheel. The elastic member enables the worm shaft to move radially, changing the center distance parameter dynamically. This allows the system to compensate for wear-induced clearance by adjusting the meshing parameters, maintaining stable transmission performance over time
2Duration of action of stationary object
If clearance is increased to accommodate wear, then durability is improved, but backlash and rattle noise increase
Solution Approach 1:
The elastic member (leaf spring) provides dynamic adjustment capability that maintains optimal meshing conditions throughout the service life. As wear occurs, the leaf spring allows the worm shaft to shift position, keeping the backlash within acceptable limits. This dynamic compensation ensures durability while preventing excessive backlash and rattle noise that would otherwise occur with fixed clearance designs
Solution Approach 2:
The system implements self-service through the automatic adjustment mechanism provided by the leaf spring. As the worm gear and worm wheel wear during operation, the elastic member automatically compensates for the increasing clearance by allowing the worm shaft to move, maintaining proper meshing without requiring external intervention or adjustment, thus preventing noise and backlash accumulation over the service life
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 system maintains smooth and convenient steering with reduced vibration and noise by compensating for clearance between the worm wheel and worm gear, providing stable steering conditions.
Implementation Method 1
an elastic member for applying a load to the first worm shaft bearing in the diametric direction... both ends of the elastic member being supported by the housing, a central portion of the elastic member abutting an outer peripheral surface of the first worm shaft bearing
Data Source
AI summary
Disclosed is an electric power steering system including a housing; a steering shaft positioned in the housing; a worm wheel mounted on the steering shaft; a worm shaft; a worm gear formed on the worm shaft so as to mesh with the worm wheel; a motor for driving the worm shaft; a first worm shaft bearing positioned on an end of the worm shaft; and an elastic member for applying a load to the first worm shaft bearing in a diametric direction, the elastic member being formed by double-folding a leaf spring in an approximately U-shaped configuration, both ends of the elastic member being supported by the housing, a central portion of the elastic member abutting an outer peripheral surface of the first worm shaft bearing.