Motorcycle CVT Roller Regulation for Smooth Shifts

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Solution Overview

Problem

Existing continuously variable transmission systems for motorcycles can only activate and deactivate the gear shift regulation device in the low gear condition, leading to limitations in gear shift curve regulation, especially at high speeds and during the gear shift phase, which results in sudden roller release and potential impact.

Innovation Solution

A transmission device with a gear shift regulation system that includes a drive pulley with centrifugal rollers and an axial load adjustment mechanism, allowing independent influence on roller movement to facilitate centrifugal displacement, enabling gear shift curve changes at both low and high speeds by using an abutment element, axial action means, and an inhibiting device to control the axial load, allowing for smoother transitions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gear shift regulation device is activated only in low gear condition, then sudden roller release and impact are avoided, but gear shift curve regulation is limited at high speeds

Engineering Contradiction:

Improveprevention of roller impactVSAvoidgear shift curve regulation capability

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The regulation device is made dynamically controllable throughout the entire operating range of the CVT. The control unit receives signals from speed sensors and dynamically adjusts the regulation device's activation state based on current operating conditions, enabling it to function in both low and high gear conditions rather than being statically limited to low gear only.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the regulation device based on engine speed and transmission ratio. By monitoring these parameters and adjusting the regulation device's activation accordingly, the system enables regulated roller release across the full operating range while adapting the regulation intensity to match current operating conditions.

Inventive Principle:

Principle #35Parameter changes

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

Enables smooth gear shift curve changes at various engine speeds, reducing clutch coupling stress during start-up and providing a more touring or sporting vehicle setup depending on the regulation device's activation, overcoming the limitations of prior art by allowing regulation at both low and high speeds.

Implementation Method 1

the drive pulley comprises a speed regulator made with centrifugal masses, generically referred to as 'rollers'

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

axial action means suitable to exert on the abutment element (22) an axial action of adjustable intensity

Methodology Applied

Scientific EffectAxial load: Mechanical Force

Data Source

PatentUS10865860B2Continuously variable transmission device with gear regulation device

Publication Date: 2020.12.15 PIAGGIO & C SPA

AI summary

A continuously variable transmission device (1) for a two-wheel, three-wheel or four-wheel motorcycle includes a gear shift regulation device suitable to operate on special rollers (18) through an adjustable axial action independently of the number of engine revolutions. The device influences the centrifugal movement of the rollers (18) and thus influences the gear shift.