Steering Reducer Damping Member for Worm Shaft Noise
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Solution Overview
Problem
The existing electric power auxiliary steering apparatus reducers experience increased clearance between the worm shaft and worm wheel due to friction, leading to noise and inaccurate steering force provision, caused by the fluctuation of the worm shaft.
Innovation Solution
A reducer design featuring a damping member with an inner and outer race, where the inner race is mounted on the worm shaft bearing and the outer race is connected to the gear housing, and a bush member with through holes to reduce impulse noise and adjust damping strength differently in various directions, effectively alleviating worm shaft fluctuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional damping member with uniform strength is used, then the structure is simple and easy to manufacture, but the worm shaft fluctuation cannot be effectively alleviated in specific directions
Solution Approach 1:
The damping member features non-uniform thickness with thinner sections at the worm wheel side and opposite side, and thicker sections at lateral sides. This local variation in thickness creates direction-dependent damping characteristics that effectively alleviate worm shaft fluctuation in the axial direction while maintaining structural integrity.
Solution Approach 2:
The damping member employs asymmetric thickness distribution where the thickness varies around the circumferential direction. Specifically, the thickness is reduced at the worm wheel side and opposite side to create preferential damping in the axial direction, while maintaining greater thickness at lateral sides for structural support.
2Manufacturing precision
If the clearance between worm shaft and worm wheel is increased, then the manufacturing tolerance is easier to achieve, but noise increases and steering force accuracy deteriorates
Solution Approach 1:
The damping member is pre-installed on the worm shaft bearing before assembly, positioned to maintain optimal clearance between the worm shaft and worm wheel. This preliminary positioning ensures that the worm shaft is held at the correct radial position, preventing excessive clearance while still allowing for manufacturing tolerances.
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 design reduces impulse noise and adjusts damping strength to effectively alleviate worm shaft fluctuation, improving the steering system's stability and accuracy by minimizing noise and ensuring precise auxiliary steering force transmission.
Implementation Method 1
strength of a damping member in a direction toward a worm wheel and an opposite direction thereto is lower than that in other directions, so that the fluctuation of the worm shaft can be more effectively alleviated
Data Source
AI summary
Disclosed is a reducer of an electric power auxiliary steering apparatus. According to embodiments of the present invention, impulse noise of a worm shaft bearing caused by fluctuation of a worm shaft can be reduced, and strength of a damping member in a direction toward a worm wheel and an opposite direction thereto is lower than that in other directions, so that the fluctuation of the worm shaft can be more effectively alleviated.