Motorcycle Transfer Case Airflow Layout for Transmission Cooling

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Solution Overview

Problem

Conventional transfer cases for motorcycles have an incompact and complex structure due to the placement of the casing and air filter on opposite sides of the frame, which hinders effective cooling of transmission components as filtered air is obstructed from reaching the side surfaces of the disks, leading to inefficient cooling.

Innovation Solution

A transfer case design with a casing unit, transmission unit, and fluid guide unit, where the fluid guide unit includes a guiding channel and filter member to direct filtered air into the casing for cooling the transmission components, with the guiding channel located between the seat unit and fuel tank, allowing for a compact structure and effective airflow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If the casing and air filter are placed on opposite sides of the frame, then the structure covers a larger area, but the structure becomes incompact and complex, and cooling effectiveness deteriorates

Engineering Contradiction:
Improvecoverage areaVSAvoidstructural complexity
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The patent merges the casing and air filter into a single integrated unit located at the same end of the motorcycle. The air filter is positioned within the casing structure, eliminating the need for separate placement on opposite sides. This integration reduces structural complexity while maintaining effective cooling through the unified design that allows direct airflow from the air filter through the guiding channel to the transmission components.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If the air filter is positioned away from the transmission components, then the casing and air filter can be separately disposed, but filtered air is obstructed from reaching the side surfaces of the disks, leading to inefficient cooling

Engineering Contradiction:
Improvemaintenance accessibilityVSAvoidcooling effectiveness
Core Design Contradiction:
Ease of operationVSTemperature

Solution Approach 1:

The patent introduces a guiding channel as an intermediary structure that directs filtered air from the air filter directly to the side surfaces of the transmission disks. This guiding channel ensures that the airflow path is optimized for cooling effectiveness while maintaining the separate positioning of the air filter and transmission components, thus preserving both maintenance accessibility and cooling performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the air outlet is positioned close to the second opening, then the structure is more compact, but airflow path is shortened and cooling effectiveness may be reduced

Engineering Contradiction:
Improvestructural compactnessVSAvoidcooling effectiveness
Core Design Contradiction:
Device complexityVSTemperature

Solution Approach 1:

The patent applies local quality by positioning the air outlet at a specific location that is optimized for both compactness and cooling effectiveness. The air outlet is disposed at the casing such that it facilitates effective cooling of the transmission components while maintaining a compact overall structure. The guiding channel ensures that air flows along an optimized path that maximizes cooling contact with the transmission components despite the compact positioning.

Inventive Principle:
Principle #3Local quality

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 ensures effective cooling of transmission components by directing filtered air directly to the disks without obstructing airflow, resulting in a more compact and efficient cooling system for the motorcycle transfer case.

Implementation Method 1

a filter member that covers the second opening and the other end of the guiding channel distal from the first opening. Ambient air is filtered by the filter member

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

a guiding channel that has one end communicating fluidly with the first opening... Ambient air is filtered by the filter member and subsequently flows into the retaining space via the second opening and via the guiding channel and the first opening

Methodology Applied
Scientific EffectFluid flow:

Implementation Method 3

flows into the retaining space via the second opening and via the guiding channel and the first opening for cooling down the transmission unit

Methodology Applied
Scientific EffectConvection cooling: Convection

Data Source

PatentEP3032143B1Transfer case and motorcycle having the same
Publication Date: 2021.01.20 KWANG YANG MOTOR LTD
  • EP3032143B1 patent drawingFigure 1
  • EP3032143B1 patent drawingFigure 2
  • EP3032143B1 patent drawingFigure 3

AI summary

A transfer case includes a casing unit (2), a transmission unit (3) and a fluid guide unit (4). The transmission unit (3) is disposed in a retaining space (23) defined in the casing unit (2). The fluid guide unit (4) including a first opening (41) proximate to one side of the transmission unit (3), a second opening (42) proximate to an opposite side of the transmission unit (3), and a guiding channel (44) communicating with the first opening (41). Ambient air flows into the retaining space (23) through the second opening (42) and through the guiding channel (44) and the first opening (41) for cooling down the transmission unit (3).