Steering Wheel Grip Rotation Control Mechanism

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Solution Overview

Problem

Conventional steering wheels do not consider the difference in maximum rotation angle based on rotation direction and fail to return grips to the neutral position effectively, leading to suboptimal operability.

Innovation Solution

A steering wheel with a rotation control mechanism that defines distinct maximum rotation angles for near-side and far-side directions and automatically returns grips to the neutral position, utilizing a rotation cam, pusher, and elastic member to adjust torque and improve grip rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the steering wheel allows free rotation of grips about the second axis, then the driver can rotate the steering wheel to a large extent without bending the wrist at an unnatural angle, but the maximum rotation angle differs between near-side and far-side directions causing suboptimal operability

Engineering Contradiction:

Improvesteering wheel operabilityVSAvoidgrip rotation angle symmetry

Core Design Contradiction:

Ease of operationVSAdaptability or versatility

Solution Approach 1:

The rotation control mechanism employs asymmetric torque characteristics that differ between near-side and far-side rotation directions. The torque applied by the rotation control mechanism varies depending on the rotation direction, allowing optimized rotation angles for each direction while maintaining natural wrist positioning during steering operations.

Inventive Principle:

Principle #4Asymmetry

Solution Approach 2:

The system dynamically adjusts the torque parameter applied to the grip based on the rotation direction and angle. By changing the torque characteristic parameter of the rotation control mechanism, the system enables different maximum rotation angles for near-side and far-side directions, optimizing operability for each steering scenario.

Inventive Principle:

Principle #35Parameter changes

2Ease of operation

If the steering wheel structure is simplified without rotation control mechanism, then the device complexity is reduced, but the grips do not return to the neutral position effectively when the vehicle is traveling straight

Engineering Contradiction:

Improvegrip return to neutral positionVSAvoidrotation control mechanism

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The rotation control mechanism utilizes the elastic recovery characteristic of the elastic member to automatically return the grip to the neutral position. The elastic member stores and releases elastic energy based on the rotation angle, creating a self-regulating system that guides the grip back to the neutral position without requiring external control inputs from the driver.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The rotation control mechanism provides tactile feedback to the driver through varying torque resistance during grip rotation. As the grip approaches the neutral position, the elastic member's restoring force increases, providing feedback that guides the driver's hand back to the correct positioning, ensuring accurate wheel alignment.

Inventive Principle:

Principle #23Feedback

3Adaptability or versatility

If the maximum rotation angle in the near-side direction is increased to match the far-side direction, then the rotation angle symmetry is improved, but the likelihood of bottoming out increases and wrist load is not optimized

Engineering Contradiction:

Improvegrip rotation angle rangeVSAvoidwrist load and bottoming out

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The rotation control mechanism provides cushioning torque through the elastic member before the grip reaches the mechanical limits of rotation. The elastic member gradually increases resistance as the rotation angle increases, cushioning the approach to the maximum rotation angle and preventing sudden bottoming out, while optimizing the rotation range for each direction based on wrist ergonomics.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

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

Enhances steering feel and operability by allowing larger rotation in the far-side direction, reducing wrist load, and ensuring smooth grip movement, with improved torque characteristics and reduced likelihood of bottoming out.

Implementation Method 1

a rotation control mechanism that includes a rotation cam, a pusher, and an elastic member

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS11608103B2Steering wheel

Publication Date: 2023.03.21 TOYODA GOSEI CO LTD

AI summary

A steering wheel includes a boss, two spokes supported at the boss, a grip fixed to each spoke, and a rotation control mechanism arranged between the boss and each spoke. The rotation control mechanisms are each configured to define a maximum rotation angle by which each grip is rotated from the neutral position in a near-side direction and a maximum rotation angle by which each grip is rotated from the neutral position in a far-side direction. The rotation control mechanisms are each configured to return each grip to the neutral position when a vehicle is traveling straight. The maximum rotation angle in the far-side direction is set to be larger than the maximum rotation angle in the near-side direction in each rotation control mechanism.