Scooter Motorcycle Intake Duct Labyrinth Structure

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Solution Overview

Problem

Scooter type motorcycles face challenges in preventing dust and water from entering the air cleaner and CVT while maintaining a compact size and ensuring sufficient air supply to both components.

Innovation Solution

The design incorporates a scooter type motorcycle with a rear wheel, a transmission case partially overlapping the rear wheel, a V-belt type CVT, and separate intake ducts for the transmission case and air cleaner, featuring a partition plate to separate inlets and a labyrinth structure to prevent dust and water entry, along with ribbed surfaces to guide water away from intake ports.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a long duct extending upward is fitted to the transmission case to prevent dust and water entry, then the CVT is protected from dust and water, but the vehicle size becomes larger

Engineering Contradiction:

Improveprotection from dust and waterVSAvoidvehicle size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent changes the orientation of the intake duct from a vertical upward extension to a lateral opening configuration. Instead of extending the duct upward (vertical dimension), the intake port is opened laterally on the side of the transmission case (lateral dimension), allowing air intake without increasing vehicle height or requiring long duct extensions.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Instead of preventing dust and water entry by extending the duct upward away from the污染源 (pollution source), the patent inverts the approach by positioning the intake port laterally and using a labyrinth structure that allows air to enter from the side while blocking contaminants from the rear wheel area.

Inventive Principle:

Principle #13The other way round (Inversion)

2Volume of moving object

If the inlet of the intake chamber for the CVT and the inlet of the intake chamber for the engine are disposed next to each other, then the structure is more compact, but one inlet may not be supplied with sufficient air when the other takes in a large amount

Engineering Contradiction:

Improvevehicle sizeVSAvoidair supply amount

Core Design Contradiction:

Volume of moving objectVSQuantity of substance

Solution Approach 1:

The patent segments the air intake system into separate lateral and rear intake ports with distinct functions. The lateral intake port serves the CVT while the rear intake port serves the engine, preventing air flow interference between the two systems while maintaining a compact overall structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent assigns different intake locations and directions to different components: the CVT receives air from a lateral port positioned away from the engine's rear port, ensuring each component has dedicated air supply pathways with appropriate flow characteristics for its specific needs.

Inventive Principle:

Principle #3Local quality

3Duration of action of stationary object

If air is introduced into the transmission case to cool the CVT, then the durability of the V-belt is improved, but dust or water may adhere to the V-belt and degrade CVT performance

Engineering Contradiction:

Improvedurability of V-beltVSAvoidCVT performance

Core Design Contradiction:

Duration of action of stationary objectVSReliability

Solution Approach 1:

The patent introduces a labyrinth structure as an intermediary between the external environment and the CVT intake port. This structure allows cool air to reach the CVT while blocking dust and water contaminants, acting as a mediator that permits necessary air flow while excluding harmful substances.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The labyrinth structure functions as a porous-like barrier that allows air molecules to pass through its complex pathways while trapping and blocking larger dust particles and water droplets, enabling selective permeability based on particle size.

Inventive Principle:

Principle #31Porous materials

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 design effectively prevents dust and water from entering the air cleaner and CVT, maintains a compact vehicle size, and ensures a sufficient air supply to both components, enhancing the durability and performance of the CVT.

Implementation Method 1

A labyrinth structure is provided to prevent entrance of mud and water from the right side

Methodology Applied

Scientific EffectLabyrinth structure:

Implementation Method 2

air is introduced into the transmission case so that the CVT is cooled by the air

Methodology Applied

Scientific EffectAir flow:

Data Source

PatentEP3321496B1Scooter type motorcycle

Publication Date: 2020.02.19 YAMAHA MOTOR CO LTD

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AI summary

A scooter type motorcycle is provided which prevents dust and water from entering the air cleaner and the CVT, inhibits the vehicle size from getting larger, and is capable of supplying a sufficient amount of air to both the air cleaner and the CVT. A side intake port (57b) for sucking air toward an inlet (27a) of an intake duct (27) for introducing a CVT (20) is formed between an air cleaner case cover (45) and a transmission case cover (30), and laterally outward of the inlet (27a). A rear intake port (60a) for sucking air toward an inlet (44a) of an intake duct (44) inside an air cleaner (40) is formed between the air cleaner case cover (45) and the transmission case cover (30), and rearward relative to the inlet (27a).