Asymmetric Straddle Vehicle Engine Bracket Design

Solution Overview

Problem

Straddle-type vehicles, such as motorcycles, face challenges in designing a front engine bracket that simultaneously reduces impact loads from uneven surfaces and maintains stability against twisting forces during cornering, as existing solutions fail to provide the necessary rigidity balance in both directions.

Innovation Solution

A bracket system for straddle-type vehicles comprising a first attachment portion attached to the down frame, a second attachment portion attached to the engine, and a coupling portion that couples them, with the first and second attachment portions offset in the vehicle width direction and the coupling portion oriented differently, allowing for adjustable rigidity in both front-to-rear and twisting directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the bracket rigidity is reduced to absorb impact loads from uneven surfaces, then the bracket can better handle front-to-rear direction impacts, but the bracket becomes less stable against twisting forces during cornering

Engineering Contradiction:

Improveimpact load absorptionVSAvoidtwisting load resistance

Core Design Contradiction:

StrengthVSStability of the object's composition

Solution Approach 1:

The bracket employs different structural configurations in different regions to achieve direction-specific rigidity characteristics. The first attachment portion connects to the down frame while the second attachment portion connects to the engine, with the coupling portion oriented at an angle to create asymmetric rigidity distribution that absorbs front-to-rear impacts while maintaining twisting stability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The bracket utilizes asymmetric geometry where the coupling portion is oriented in a direction different from the first and second attachment portions. This asymmetric configuration creates different rigidity characteristics along different axes, allowing the bracket to be more compliant in the front-to-rear direction while maintaining higher rigidity against twisting forces

Inventive Principle:

Principle #4Asymmetry

2Stability of the object's composition

If the bracket rigidity is increased to prevent engine rising during cornering, then the bracket can better resist twisting forces, but the bracket becomes less effective at absorbing impact loads from uneven surfaces

Engineering Contradiction:

Improvetwisting load resistanceVSAvoidimpact load absorption

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The bracket employs different structural configurations in different regions to achieve direction-specific rigidity characteristics. The first attachment portion connects to the down frame while the second attachment portion connects to the engine, with the coupling portion oriented at an angle to create asymmetric rigidity distribution that absorbs front-to-rear impacts while maintaining twisting stability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The bracket utilizes asymmetric geometry where the coupling portion is oriented in a direction different from the first and second attachment portions. This asymmetric configuration creates different rigidity characteristics along different axes, allowing the bracket to be more compliant in the front-to-rear direction while maintaining higher rigidity against twisting forces

Inventive Principle:

Principle #4Asymmetry

3Reliability

If the bracket is designed with high rigidity in all directions, then the engine is well-supported against all loads, but the bracket cannot effectively absorb impact loads from uneven surfaces

Engineering Contradiction:

Improveengine support stabilityVSAvoidimpact load absorption

Core Design Contradiction:

ReliabilityVSStrength

Solution Approach 1:

The bracket employs different structural configurations in different regions to achieve direction-specific rigidity characteristics. The first attachment portion connects to the down frame while the second attachment portion connects to the engine, with the coupling portion oriented at an angle to create asymmetric rigidity distribution that absorbs front-to-rear impacts while maintaining twisting stability

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The bracket utilizes asymmetric geometry where the coupling portion is oriented in a direction different from the first and second attachment portions. This asymmetric configuration creates different rigidity characteristics along different axes, allowing the bracket to be more compliant in the front-to-rear direction while maintaining higher rigidity against twisting forces

Inventive Principle:

Principle #4Asymmetry

Data Source

PatentUS9463838B2Straddle-type vehicle

Publication Date: 2016.10.11 YAMAHA MOTOR CO LTD

AI summary

A straddle-type vehicle includes a bracket including a first attachment portion, a second attachment portion and a coupling portion. The first attachment portion is attached to a down frame. The second attachment portion is attached to an engine and is located rearward of the first attachment portion. The coupling portion is located between the first and second attachment portions and couples the first attachment portion with the second attachment portion. The first and second attachment portions extend in the front-to-rear direction. The first attachment portion is offset relative to the second attachment portion in a vehicle width direction. In a plan view of the vehicle, the coupling portion is oriented in or substantially in a front-to-rear direction with respect to the vehicle and extends in a direction different from that of the first and second attachment portions.