Hybrid Steering Shaft Support for Low-Friction NVH Control
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Solution Overview
Problem
Traditional steering systems exhibit high friction and noise/vibration due to the mounting of roller/ball bearings, which affects the performance of the steering assembly.
Innovation Solution
A hybrid shaft support is introduced, comprising a cylindrical member and a flexible seal over-molded onto the cylindrical member, with an outer rib, inner rib, and recess to prevent debris and reduce friction, noise, and vibration, formed from polymeric materials with varying hardness and modulus of elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If roller/ball bearing is tightly mounted to the housing or input shaft, then the bearing is securely supported, but friction and noise/vibration increase
Solution Approach 1:
The patent introduces a hybrid shaft support as an intermediary component between the input shaft and housing. This hybrid support includes a seal member with a bearing interface that mediates the contact between the bearing and input shaft, reducing direct metal-to-metal contact and thereby reducing friction and noise while maintaining secure support.
Solution Approach 2:
The patent changes the material parameters of the bearing support interface by using a seal member made of elastomeric material with specific durometer hardness (40-90 durometer). This parameter change from rigid metal to flexible elastomer reduces friction coefficients and dampens vibrations, solving the contradiction between support stability and noise reduction.
2Object-affected harmful factors
If seal is mounted in contact around the input shaft, then external debris is prevented from entering the housing, but friction and noise/vibration transmissions increase
Solution Approach 1:
The patent employs a composite structure where the seal member is integrally formed with a bearing interface, combining the sealing function and bearing support function in a single composite component. The elastomeric material provides both sealing capability and low-friction bearing surface, eliminating the need for separate seal and bearing components that would otherwise transmit noise and vibration.
3Ease of manufacture
If bearing is separately supported by the housing, then the bearing is easily installed, but friction and noise/vibration transmissions increase
Solution Approach 1:
The patent merges the seal function and bearing support function into a single hybrid shaft support component. The seal member with bearing interface integrates two previously separate functions, maintaining ease of installation as a single unit while eliminating the noise and vibration transmission associated with separate bearing mounts.
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 hybrid shaft support significantly reduces friction, noise, and vibration in the steering assembly by providing a low-friction surface and stabilizing the input shaft against side loads while preventing debris entry.
Implementation Method 1
a flexible seal over-molded onto the cylindrical member... formed from a polymeric material wherein the hardness and modulus of elasticity may differ
Data Source
AI summary
A steering system for a vehicle includes a housing, an input shaft, and a hybrid shaft support. The housing defines an opening. The input shaft is configured to rotate about an input axis. The hybrid shaft support may be disposed at the opening and configured to couple the input shaft to the housing. The hybrid shaft support may also be configured to support the input shaft as the input shaft rotates. The hybrid shaft support further includes a cylindrical member and a flexible seal over-molded onto the cylindrical member.