Zero Caster Steering Axis for Steer-by-Wire Suspension

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Solution Overview

Problem

Conventional vehicle suspension systems with direct mechanical steering connections face challenges in managing mechanical self-alignment, pneumatic self-alignment, and jacking effects, leading to increased tire wear and wheel rolling resistance, especially in steer-by-wire configurations where direct mechanical control is lacking.

Innovation Solution

A vehicle suspension system with a steering axis having a zero-degree caster inclination angle, allowing for electronic control of wheel steering, which reduces mechanical self-alignment and pneumatic self-alignment effects, enabling lighter and smaller suspension and steering components, and facilitating steer-by-brake functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional steering systems with direct mechanical connections are used, then mechanical self-alignment and pneumatic self-alignment are provided, but this increases tire wear and wheel rolling resistance

Engineering Contradiction:
Improvemechanical self-alignmentVSAvoidtire wear
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the conventional mechanical steering connection with an electronic control system. The steering wheel is mechanically disconnected from the steering mechanism, and steering control is achieved through electronic sensors and actuators that detect wheel position and apply corrective forces without direct mechanical linkage. This substitution eliminates the mechanical self-alignment effects that cause tire wear while maintaining steering control through electronic means.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the direct mechanical connection between the steering wheel and the steering mechanism. By taking out this mechanical linkage, the system eliminates the source of mechanical self-alignment and jacking effects that lead to increased tire wear and rolling resistance, while retaining steering functionality through electronic control systems.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If conventional steering systems with direct mechanical connections are used, then mechanical self-alignment and pneumatic self-alignment are provided, but this increases wheel rolling resistance

Engineering Contradiction:
Improvemechanical self-alignmentVSAvoidwheel rolling resistance
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces the conventional mechanical steering connection with an electronic control system. The steering wheel is mechanically disconnected from the steering mechanism, and steering control is achieved through electronic sensors and actuators that detect wheel position and apply corrective forces without direct mechanical linkage. This substitution eliminates the mechanical self-alignment effects that cause tire wear while maintaining steering control through electronic means.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the direct mechanical connection between the steering wheel and the steering mechanism. By taking out this mechanical linkage, the system eliminates the source of mechanical self-alignment and jacking effects that lead to increased tire wear and rolling resistance, while retaining steering functionality through electronic control systems.

Inventive Principle:
Principle #2Taking out (Extraction)

3Stability of the object's composition

If an inclined steering axis is used to provide mechanical self-alignment, then directional stability is improved, but this increases tire wear and wheel rolling resistance

Engineering Contradiction:
Improvedirectional stabilityVSAvoidtire wear
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the conventional mechanical steering connection with an electronic control system. The steering wheel is mechanically disconnected from the steering mechanism, and steering control is achieved through electronic sensors and actuators that detect wheel position and apply corrective forces without direct mechanical linkage. This substitution eliminates the mechanical self-alignment effects that cause tire wear while maintaining steering control through electronic means.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the steering axis configuration from an inclined design to a vertical orientation. By making the steering axis vertical rather than inclined, the system eliminates the creation of moment arms that generate jacking effects and mechanical self-alignment forces, thereby reducing tire wear and rolling resistance while maintaining directional stability through electronic control.

Inventive Principle:
Principle #35Parameter changes

4Stability of the object's composition

If an inclined steering axis is used to provide mechanical self-alignment, then directional stability is improved, but this increases wheel rolling resistance

Engineering Contradiction:
Improvedirectional stabilityVSAvoidwheel rolling resistance
Core Design Contradiction:
Stability of the object's compositionVSLoss of energy

Solution Approach 1:

The patent replaces the conventional mechanical steering connection with an electronic control system. The steering wheel is mechanically disconnected from the steering mechanism, and steering control is achieved through electronic sensors and actuators that detect wheel position and apply corrective forces without direct mechanical linkage. This substitution eliminates the mechanical self-alignment effects that cause tire wear while maintaining steering control through electronic means.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the steering axis configuration from an inclined design to a vertical orientation. By making the steering axis vertical rather than inclined, the system eliminates the creation of moment arms that generate jacking effects and mechanical self-alignment forces, thereby reducing tire wear and rolling resistance while maintaining directional stability through electronic control.

Inventive Principle:
Principle #35Parameter changes

5Ease of operation

If HPAS or EPAS systems are used to assist steering, then steering effort is reduced, but the system must continually overcome mechanical self-alignment, pneumatic self-alignment, and jacking effects

Engineering Contradiction:
Improvesteering effortVSAvoidsteering system energy consumption
Core Design Contradiction:
Ease of operationVSUse of energy by moving object

Solution Approach 1:

The patent replaces the conventional mechanical steering connection with an electronic control system. The steering wheel is mechanically disconnected from the steering mechanism, and steering control is achieved through electronic sensors and actuators that detect wheel position and apply corrective forces without direct mechanical linkage. This substitution eliminates the mechanical self-alignment effects that cause tire wear while maintaining steering control through electronic means.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the direct mechanical connection between the steering wheel and the steering mechanism. By taking out this mechanical linkage, the system eliminates the source of mechanical self-alignment and jacking effects that lead to increased tire wear and rolling resistance, while retaining steering functionality through electronic control systems.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentUS10351162B1Suspension architecture for steer-by-wire vehicle
Publication Date: 2019.07.16 APPLE INC
  • US10351162B1 patent drawing
  • US10351162B1 patent drawing
  • US10351162B1 patent drawing

AI summary

A vehicle has a wheel, a frame, a suspension component, a steering knuckle, and a steering system. The suspension component is connected to the frame. The steering knuckle is connected to the suspension component and is connected to the wheel. The suspension component is operable to control vertical movement of the steering knuckle and the wheel relative to the frame. The suspension component and the steering knuckle define a steering axis for the wheel. The steering axis has a caster inclination angle of zero degrees. The steering system is connected to the suspension component and controls a steering angle of the wheel based on an electronic control signal.