Leaning Vehicle Rotor Locking for Low-Force Tilt Control

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Solution Overview

Problem

Existing leaning vehicles with motors for tilting the vehicle body face the issue of excessive force being applied to the lock mechanism when the motor is activated while the lock mechanism is engaged, potentially damaging it.

Innovation Solution

A leaning vehicle design incorporating a deceleration mechanism in the rotational path of the motor's output shaft, coupled with a lock mechanism that restricts rotation upstream, using a dog-type lock mechanism with a pawl and protrusion system to prevent excessive force application, and featuring a spring and wire mechanism for controlled engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the motor is activated while the lock mechanism is activated, then the vehicle body can be tilted, but excessive force is applied to the lock mechanism causing potential damage

Engineering Contradiction:
Improvemotor activation capabilityVSAvoidlock mechanism durability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The rotating mechanism is divided into multiple stages: the motor rotates the rotor, which drives the rotating shaft, then the deceleration mechanism, and finally the output shaft connects to the link mechanism. This segmentation allows the lock mechanism to engage with the rotor at an upstream position where less force is transmitted, protecting it from excessive force while still enabling motor activation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The deceleration mechanism acts as an intermediary between the rotating shaft and the output shaft. It reduces the rotational speed while increasing torque, but more importantly for this invention, it creates a force distribution where the lock mechanism engaging upstream experiences reduced force compared to engaging downstream near the high-torque output shaft.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the lock mechanism restricts rotation downstream of the rotating mechanism, then the vehicle body tilt is prevented, but excessive force is applied to the lock mechanism when the motor is activated

Engineering Contradiction:
Improvevehicle body stabilityVSAvoidforce on lock mechanism
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

Instead of locking downstream near the output shaft where high torque exists, the lock mechanism is inverted to lock upstream at the rotor. This reverse approach to where the lock is applied means the same locking action now experiences much lower forces because it is before the deceleration mechanism multiplies torque.

Inventive Principle:
Principle #13The other way round (Inversion)

3Force

If the lock mechanism is configured to restrict rotation upstream of the output shaft, then excessive force is reduced on the lock mechanism, but the complexity of the transmission path increases

Engineering Contradiction:
Improveforce on lock mechanismVSAvoidtransmission path complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The rotor serves multiple functions: it is the rotating component driven by the motor, it is the element that the lock mechanism engages with for securing the vehicle body, and it is part of the deceleration mechanism's input. This multi-functionality means that locking the rotor achieves the security function without requiring additional dedicated locking components in the transmission path, thus not increasing overall device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 design effectively prevents excessive force from being applied to the lock mechanism, ensuring stable and reliable prevention of vehicle body tilt without unintentional activation, while maintaining the vehicle in an upright position.

Implementation Method 1

a deceleration mechanism that transmits rotation of the rotating shaft while reducing speed of rotation

Methodology Applied
Scientific EffectMechanical Advantage: Mechanical Advantage

Implementation Method 2

featuring a spring and wire mechanism for controlled engagement

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4488157B1Leaning vehicle
Publication Date: 2025.11.05 YAMAHA MOTOR CO LTD
  • EP4488157B1 patent drawingFigure 1
  • EP4488157B1 patent drawingFigure 2
  • EP4488157B1 patent drawingFigure 3

AI summary

A leaning vehicle 1 includes a lean motor 30 that drives a link mechanism 20 to thereby tilt a vehicle body frame 10. The lean motor 30 includes a case 31 fixed to the vehicle body frame 10, a stator 32 fixed to the case 31, a rotor 33 rotatably supported on the case 31, a rotating shaft 34 that rotates together with the rotor 33, a deceleration mechanism 35 that transmits the rotation of the rotating shaft 34 while reducing the speed of rotation, and an output shaft 36 connected to the deceleration mechanism 35 and the link mechanism 20. The leaning vehicle 1 includes a lock mechanism 40 that restricts the rotation of the rotor 33 to thereby prevent the vehicle body frame 10 from tilting.