Worm Shaft Bearing Assembly With Elastic Pivot Ring for Backlash Noise
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bearing arrangements in electromechanical power steering systems suffer from gear play and noise issues due to the geometry of worm shaft and worm wheel interactions, leading to undesirable noises, especially during alternating steering, and previous solutions have either increased noise or compromised reliability.
Innovation Solution
A bearing arrangement featuring a first pivot bearing, a second pivot bearing, and a pivot ring with resilient points that form axes, allowing the worm shaft to be biased against the worm wheel, reducing gear play and noise through a preload mechanism that adjusts based on load direction and torque, and is designed for a simple construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the worm shaft is pushed away from the worm wheel under load due to gear geometry, then the gear meshing is maintained, but backlash increases and noise occurs
Solution Approach 1:
The bearing arrangement applies a preliminary counteracting force through the resilient swivel ring that pushes the worm shaft toward the worm wheel, opposing the load-induced separation force. This preliminary action maintains consistent gear meshing contact and eliminates backlash before it can occur during operation.
Solution Approach 2:
The swivel ring is designed with resilient properties that allow it to dynamically adapt its preload force on the worm shaft based on the direction and magnitude of applied loads. This dynamic adjustment ensures optimal gear contact under varying operating conditions while minimizing noise and backlash.
2Force
If a spring washer is used to resist axial forces, then some axial support is provided, but the washer is rigid against radial forces and offers little resistance to tilting movements
Solution Approach 1:
The resilient swivel ring serves multiple functions simultaneously: it provides axial support through its resilient design, resists radial forces through its structural configuration, and prevents tilting movements of the worm shaft through its pivotable connection to the bearing. This multi-functional design eliminates the need for separate components for each function.
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 consistently provides reliable, low-noise operation by reducing gear play and preventing unwanted rattling noises during operation, with the pivot axis position dependent on the direction of rotation and load, ensuring effective noise reduction and structural simplicity.
Implementation Method 1
The swivel ring (21) is designed to act resiliently between the second rotary bearing (20) and the housing (22)
Data Source
Figure 1~2
Figure 3~4a
Figure 4b~4d
AI summary
The invention relates to a bearing assembly for supporting a worm shaft (12), which meshes with a worm gear (14), in a housing of an electromechanical power steering system. The bearing assembly comprises a first rotary bearing (19), a second rotary bearing (20), and a pivot ring (21), wherein the first rotary bearing (19) is designed to allow a pivoting movement of the worm shaft (12), and the pivot ring (21) comprises a first pivot ring component (24, 36) and a second pivot ring component (25, 37) and is designed to produce an elastic effect between the second rotary bearing (20) and the housing (22). The second rotary bearing (20) is arranged at least partly between the first pivot ring component (24) and the second pivot ring component (25, 37). The first pivot ring component (24) has two first points, with respect to which the first pivot ring component (24) is designed to be elastic, and the second pivot ring component (25) has two second points, with respect to which the second pivot ring component (25) is designed to be elastic. The invention additionally relates to an electromechanical power steering system with a drive module which comprises such a bearing assembly.