Vehicle Steering Mechanism with Variable Trail Length

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Solution Overview

Problem

In vehicles with a variable trail length mechanism, the drive source is typically heavy and spaced away from the steering axis, increasing steering inertia and requiring excessive force for steering operations.

Innovation Solution

The vehicle design includes an electric motor as the drive source, supported by the vehicle body and positioned anterior to the steering rotation unit, with a screw mechanism translating its rotation to linear motion, and a speed reducer and lock mechanism to optimize torque and compactness, allowing the drive source to be close to the steering axis, reducing steering inertia.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the drive source is supported by the oscillation unit that oscillates to vary the trail length, then the oscillation unit can be driven effectively, but the drive source having a relatively heavy weight being spaced away from the steering axis increases steering inertia and requires large force for steering operation

Engineering Contradiction:
Improvedrive source effectivenessVSAvoidsteering operation force
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent separates the drive source (motor 42) from the oscillation unit (41), supporting the motor on the vehicle body instead. This segmentation allows the heavy drive source to be positioned independently away from the oscillating components, reducing its impact on steering inertia while maintaining effective drive transmission to the oscillation unit through the screw mechanism (43).

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a screw mechanism (43) as an intermediary between the drive source and the oscillation unit. This mediator transmits the driving force from the motor to the oscillation unit effectively, ensuring that the drive source can be positioned optimally for reducing steering inertia while still providing sufficient power to vary the trail length.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If the drive source is positioned away from the steering axis to oscillate the oscillation unit, then the trail length can be varied, but steering inertia increases making steering operation difficult

Engineering Contradiction:
Improvetrail length variationVSAvoidsteering operation
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent divides the system into independent components: the drive source (motor 42) is supported on the vehicle body, while the oscillation unit (41) remains connected to the steering rotation unit (13). This segmentation allows the drive source to be positioned away from the steering axis, enabling trail length variation without significantly increasing steering inertia, as the heavy motor does not oscillate with the steering system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The screw mechanism (43) serves as an intermediary that transmits rotational motion from the drive source to linear motion for oscillating the oscillation unit. This intermediary allows effective trail length variation while keeping the drive source positioned optimally, maintaining ease of steering operation by decoupling the heavy motor from the oscillating mass.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This configuration reduces steering inertia, enabling easier and more efficient steering operations by positioning the drive source close to the steering axis, enhancing the vehicle's maneuverability and control.

Implementation Method 1

a screw mechanism (43) that translates rotation of the electric motor (42) to linear motion to thereby oscillate the oscillation unit (41)

Methodology Applied
Scientific EffectScrew mechanism: Screw

Data Source

PatentEP3345818B1Vehicle steering mechanism
Publication Date: 2020.06.24 HONDA MOTOR CO LTD
  • EP3345818B1 patent drawingFigure 1
  • EP3345818B1 patent drawingFigure 2
  • EP3345818B1 patent drawingFigure 3

AI summary

To enable, in a vehicle including a variable trail length mechanism, steering inertia to be reduced. A vehicle includes a vehicle body (10) and a front wheel that is disposed anterior to the vehicle body (10) and that is steerable about a steering axis (Cs). The vehicle body (10) includes a vehicle body frame (11) and a steering rotation unit (13) that is supported on the vehicle body frame (11) and that rotates about the steering axis (Cs). The vehicle includes a variable trail length mechanism (30). The variable trail length mechanism (30) includes an oscillation unit (41) that supports front forks (25L and 25R) that are disposed to be oscillatable in a fore-aft direction and that support the front wheel, and an electric motor (42) that oscillates the oscillation unit (41). The electric motor (42) is supported by the vehicle body (10).