Steering Device Buffer Member for Consistent Rack Guide Alignment
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Solution Overview
Problem
Conventional steering devices experience differences in steering feel between turning and turning back due to the O-ring's shape being influenced by previous steering operations, leading to uneven alignment and friction changes.
Innovation Solution
A steering device with a rack and pinion mechanism, incorporating a buffer member with a cylindrical member and an elastic member that absorbs stress and maintains alignment, preventing excessive inclination and noise, ensuring consistent steering feel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If an O-ring is disposed on the rack retainer to maintain alignment, then the alignment between rack retainer and housing is improved, but the steering feel becomes uneven between turning and turning back due to O-ring shape deformation from previous operations
Solution Approach 1:
The patent changes the material parameter from a conventional O-ring to a buffer member made of viscoelastic material, which has different mechanical properties including stress relaxation capabilities. This material parameter change allows the buffer member to recover from deformation more effectively, maintaining consistent steering feel while preserving alignment stability.
Solution Approach 2:
The buffer member is constructed as a composite structure with a cylindrical member and an elastic member disposed on its inner or outer circumferential surface. This composite design combines the structural support of the cylindrical member with the elastic recovery properties of the elastic member, resolving the contradiction between maintaining alignment and ensuring consistent steering feel.
2Device complexity
If the O-ring is used to guide the rack bar, then the structural simplicity is maintained, but the steering operation becomes disturbed due to shape memory effects from previous operations
Solution Approach 1:
The patent introduces a buffer member with specific viscoelastic material properties that exhibit stress relaxation behavior. This parameter change in material characteristics allows the buffer member to quickly recover from deformation caused by previous steering operations, ensuring smooth steering operation while maintaining a relatively simple structural configuration.
Solution Approach 2:
The buffer member acts as an intermediary element between the rack retainer and the housing, absorbing and dissipating the effects of previous steering operations. This mediator function allows the system to maintain structural simplicity while achieving smooth steering operation through the buffer member's elastic recovery properties.
3Reliability
If the rack guide is pressed against the rack shaft to maintain engagement, then the engagement reliability is improved, but friction variations occur due to rack guide inclination from previous operations
Solution Approach 1:
The patent employs a buffer member made of viscoelastic material that exhibits stress relaxation properties. This material parameter change enables the buffer member to absorb inclination forces and maintain consistent contact pressure between the rack guide and rack shaft, ensuring both engagement reliability and friction consistency during steering operations.
Solution Approach 2:
The buffer member provides beforehand cushioning by absorbing and dissipating the effects of previous steering operations before they can cause inclination and friction variations. This prior cushioning action maintains reliable engagement while ensuring consistent friction characteristics during subsequent steering operations.
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 buffer member ensures smooth steering operations by maintaining alignment and reducing friction variations, preventing differences in steering feel between turning and turning back, thus enhancing the overall steering experience.
Implementation Method 1
a buffer member provided between an outer circumferential surface of the rack guide and an inner circumferential surface of the guide housing. The buffer member has a cylindrical member and an elastic member. The elastic member is disposed on at least either one of an inner circumferential surface and an outer circumferential surface of the cylindrical member.
Implementation Method 2
a biasing member that biases the rack guide against the rack shaft to press the rack against the pinion
Data Source
AI summary
A steering device includes: a rack; a pinion; a pinion shaft having the pinion on an outer circumferential surface thereof; a rack shaft having the rack that engages with the pinion; a rack guide that is provided on a side of the rack shaft opposite from the pinion shaft and guides the rack shaft along an axis of the rack shaft; a biasing member that biases the rack guide against the rack shaft to press the rack against the pinion; a guide housing that accommodates the rack guide and the biasing member; and a buffer member provided between an outer circumferential surface of the rack guide and an inner circumferential surface of the guide housing. The buffer member has a cylindrical member and an elastic member. The elastic member is disposed on at least either one of an inner circumferential surface and an outer circumferential surface of the cylindrical member.