Motorcycle Synchronized Transmission Cam Actuator

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Solution Overview

Problem

Existing synchronized transmissions in vehicles require precise and repeatable actuation sequences for synchronizers to achieve different transmission speeds, which is challenging to implement effectively.

Innovation Solution

A synchronized transmission system with a specific arrangement of toothed pulleys and belts, including a centrifugal clutch and actuated synchronizers, allows for precise control of speed changes through a predetermined sequence using an electric motor and cam followers, ensuring consistent engagement and disengagement of gear ratios.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If two synchronizers are provided with precise actuation sequences, then different transmission speeds can be achieved, but the actuation timing and sequence control becomes complex and difficult to implement

Engineering Contradiction:
Improvetransmission speed variationVSAvoidsynchronizer actuation control
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent combines the actuation control of two synchronizers into a single integrated mechanism. The cam actuator with follower simultaneously controls both synchronizers through mechanically linked cam lobes, eliminating the need for separate actuation systems and reducing overall control complexity while maintaining the ability to achieve different transmission speeds

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a cam actuator as an intermediary mechanism between the control input and the two synchronizers. The cam profile acts as a mediator that automatically sequences the actuation of both synchronizers through its geometric design, transforming a complex timing control problem into a simple mechanical follower movement

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If synchronizers are actuated with precise sequence and timing, then speed changes can be controlled, but repeatable and continuous operation becomes challenging

Engineering Contradiction:
Improvespeed change controlVSAvoidrepeatable continuous operation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The cam actuator mechanism is designed to automatically reset and repeat its cycle without external intervention. The mechanical follower returns to its initial position after each actuation cycle through spring force or gravitational action, enabling the cam lobes to automatically re-engage and repeat the precise sequencing for continuous reliable operation

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs periodic cyclic action through the cam actuator mechanism. The cam lobes are designed with periodic profiles that automatically repeat the synchronizer actuation sequence at regular intervals, ensuring consistent and reliable speed changes with each transmission cycle without requiring complex control systems

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

This solution guarantees the implementation of each synchronizer according to a prefixed scheme, ensuring repeatable and efficient speed changes without clutch or sliding losses, enhancing the transmission's reliability and efficiency.

Implementation Method 1

a centrifugal clutch and actuated synchronizers

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3548325B1Synchronized transmission
Publication Date: 2023.08.16 PIAGGIO & C SPA
  • EP3548325B1 patent drawingFigure 1
  • EP3548325B1 patent drawingFigure 2
  • EP3548325B1 patent drawingFigure 3~4

AI summary

A synchronized transmission (1) used in a motorcycle, wherein a crankshaft actuated by the engine and a driven shaft, connected to a rear wheel, are substantially parallel and kinematically connected therebetween, comprising a first axial actuation synchronizer (16) placed at the front of the crankshaft (2) and a second axial actuation synchronizer (17) arranged at the front of a driven shaft kinematically connected to a rear wheel, each synchronizer (16, 17) comprising a respective rotating cam actuator (26, 29) having a cam (29) apt to be rotated by a respective cam spindle (30) by determining a translation thereof which interferes with an actuation end of the respective synchronizer (16, 17).