Motorcycle CVT Roller Regulator for Fuel Economy

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Solution Overview

Problem

Current continuously variable transmission systems for motorcycles lack the ability to efficiently reduce fuel consumption and pollutant emissions while providing adaptability to rider needs, and are not simple or economical to manufacture.

Innovation Solution

A transmission system with a regulator device that selectively activates specific rollers on the drive sheave to alter the gear change curve, allowing for 'sports' or 'touring' modes, thereby optimizing gear change parameters to reduce fuel consumption and emissions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If traditional centrifugal transmission solution is used, then the transmission system is simple and economical to manufacture, but it lacks the ability to reduce fuel consumption and pollutant emissions effectively

Engineering Contradiction:
Improvemanufacturing simplicityVSAvoidpollutant emissions
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The drive sheave is segmented into multiple independent roller groups (first group, second group, third group) that can be selectively activated. This segmentation allows the system to optimize gear change characteristics for different driving conditions, reducing fuel consumption and emissions while maintaining manufacturing simplicity through modular design.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transmission system dynamically selects which roller groups are active based on driving conditions (sport mode vs. economy mode). This dynamic configuration allows optimization of the gear change curve to reduce fuel consumption and emissions without requiring a complete redesign of the transmission system.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If electromechanical system with electric motor is used, then the gear change can be managed according to desired map, but the device complexity and manufacturing cost increase significantly

Engineering Contradiction:
Improvegear change adaptabilityVSAvoidsystem complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The centrifugal rollers serve multiple functions: they provide the basic speed regulation function and simultaneously enable multiple gear change characteristics (sport mode, economy mode) through selective activation. This multi-functionality achieves gear change adaptability without requiring separate control systems for each mode.

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

Solution Approach 2:

The transmission system uses its own centrifugal rollers to provide multiple operating modes through selective engagement, rather than requiring an external electric motor and electronic control system. The system serves itself by utilizing existing components in different configurations.

Inventive Principle:
Principle #25Self-service

3Speed

If all centrifugal rollers are always active, then the transmission responds quickly to speed changes, but fuel consumption increases

Engineering Contradiction:
Improvespeed responseVSAvoidfuel consumption
Core Design Contradiction:
SpeedVSUse of energy by moving object

Solution Approach 1:

Different roller groups are activated periodically or selectively based on driving conditions. In economy mode, only essential roller groups are active, reducing energy consumption. In sport mode, all roller groups are activated for rapid speed response. This periodic/selective activation optimizes the balance between speed response and fuel consumption.

Inventive Principle:
Principle #19Periodic action

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 system achieves reduced fuel consumption and pollutant emissions by modifying gear change parameters, enhancing the adaptability of the motorcycle to rider needs, and offering a simple and economical solution by acting on the transmission system rather than the drive unit.

Implementation Method 1

The drive sheave usually comprises a speed regulator made with centrifugal masses (rollers) which have the purpose of performing the aperture of the respective half-sheaves

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2791551B1Transmission system with device for regulating the gear change curve
Publication Date: 2019.05.01 PIAGGIO & C SPA
  • EP2791551B1 patent drawingFigure 1~2
  • EP2791551B1 patent drawingFigure 3~4
  • EP2791551B1 patent drawingFigure 5a~5c

AI summary

A continuously variable transmission system for a motor cycle is described, comprising a first drive sheave (12) operated by a transmission half-shaft (14) and a second driven sheave, connected to each other by a V- belt. At least the drive sheave (12) is composed of a first half-sheave (16) and a second half-sheave (18) substantially conical, sliding on the same axis, joined in rotation. The first half sheave (16) is fitted internally with a speed regulator composed of a plurality of centrifugal masses (20) the movement of which is able to cause the axial shift, in the direction of extension of the transmission half-shaft (14), of said first half-sheave (16) in relation to the corresponding second half-sheave (18). The transmission system comprises a device (10) for regulating the gear change curve provided with electromechanical actuation means able to cause the selective intervention of a determined group of centrifugal masses (20), in such a way as to vary, for the same number of revs of the engine, the centrifugal force needed to achieve the axial shift of the first half-sheave (16) in relation to the corresponding second half-sheave (18).