Eccentric Ring Damping for Rack-and-Pinion Steering Noise
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Solution Overview
Problem
Rack and pinion steering systems in motor vehicles experience noise and shock issues due to mechanical interactions during steering maneuvers, particularly during parking, which are not adequately addressed by existing damping solutions.
Innovation Solution
Incorporation of a fixed ring with eccentric bearing surfaces and damping means around the rack, which applies forces to the rack to limit shock and noise by adjusting the direction and value of eccentricity, ensuring proper contact and operation with the pusher device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pusher device is used to press the rack against the pinion, then proper meshing contact is ensured, but shocks and noise occur during steering maneuvers
Solution Approach 1:
A fixed ring with damping means is introduced as an intermediary element between the rack and the pusher device. This ring absorbs shocks and reduces noise while maintaining the necessary contact force between the rack and pinion, thereby resolving the contradiction between reliable meshing and harmful shocks/noise
Solution Approach 2:
The damping characteristics of the fixed ring are optimized by adjusting parameters such as the eccentricity of bearing surfaces and the properties of damping materials (e.g., O-ring cross-section, silicone overmoulding thickness) to achieve the desired balance between contact pressure and shock absorption
2Object-generated harmful factors
If damping means are added to reduce shocks, then noise is reduced, but device complexity increases
Solution Approach 1:
The fixed ring serves multiple functions simultaneously: it provides damping to reduce noise, guides the rack through its bearing surfaces, and maintains proper positioning. This multi-functionality reduces the need for separate components, thereby limiting the increase in device complexity
Solution Approach 2:
The damping means utilize flexible elements such as an O-ring mounted in an annular groove or a silicone overmoulding layer. These thin, flexible structures provide effective damping with minimal added complexity and space requirements
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
Significantly reduces shocks and noise at contact zones between the rack and pinion, as well as between the pusher and housing, while maintaining proper operation of the steering system, even under varying loads and wear conditions.
Implementation Method 1
the ring internally having eccentric bearing surfaces in frictional contact with the rack
Implementation Method 2
The damping means can be constituted by a damping element of annular shape, placed at the periphery of the ring
Implementation Method 3
the ring internally having eccentric bearing surfaces in frictional contact with the rack
Data Source
Figure 1~6
Figure 7~10
Figure 11~14
AI summary
The system has a toothed rack (3) mounted in a longitudinal direction in a slidable manner. A steering pinion is engaged with the toothed rack. A push rod elastically pushes the toothed rack against the steering pinion. A ring is fixed with a silicone O-ring and mounted around the toothed rack. The ring is internally provided with an eccentric portion (15), which is provided in frictional engagement with the toothed rack. The O-ring is mounted in an annular groove, which is formed in a periphery of the ring.