Under-Seat Storage Box Layout for Rear Fender Clearance

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Solution Overview

Problem

Straddled vehicles face interference issues when increasing the size of a storage box to accommodate large helmets, which interferes with devices disposed below it.

Innovation Solution

The storage box is designed with a bulge portion bulging downward in its bottom surface, allowing large helmets to be stored with their tops oriented downward, and positioned above the fender front portion to avoid interference with the rear fender's movable range, while also incorporating a recess for smaller helmets and compactly placing engine auxiliary devices within the recess.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the storage box is increased in size to accommodate large-sized helmets, then the storage space is improved, but interference with devices disposed below the storage box occurs

Engineering Contradiction:
Improvestorage spaceVSAvoidinterference with devices below
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The storage box utilizes the vertical space above the rear fender by creating a bulge portion that extends downward into the available volume. This dimensional approach allows the storage box to access three-dimensional space that would otherwise be unused, accommodating large helmets without horizontal expansion that would cause interference with below devices.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The design accounts for the dynamic movement of the rear fender by positioning the bulge portion to clear the fender's movable range. The bulge portion is shaped and positioned to maintain clearance throughout the fender's motion cycle, allowing the storage box to be enlarged while avoiding interference during vehicle operation.

Inventive Principle:
Principle #15Dynamics

2Volume of moving object

If the storage box is enlarged to store large-sized helmets, then the storage capacity is improved, but interference with the movable range of the rear fender occurs

Engineering Contradiction:
Improvestorage capacityVSAvoidrear fender movement
Core Design Contradiction:
Volume of moving objectVSEase of operation

Solution Approach 1:

The storage box exploits the vertical dimension above the rear fender by extending a bulge portion downward into the available space. This allows the storage capacity to increase without horizontal expansion that would interfere with the rear fender's lateral movement and operational range.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The bulge portion is specifically positioned and shaped to clear the dynamic path of the rear fender during movement. The design ensures that the bulge portion maintains adequate clearance throughout the fender's full range of motion, preserving ease of operation while maximizing storage capacity.

Inventive Principle:
Principle #15Dynamics

3Volume of moving object

If the bulge portion is enlarged to increase storage space, then the helmet storage capability is improved, but interference with the air cleaner occurs

Engineering Contradiction:
Improvehelmet storage capabilityVSAvoidinterference with air cleaner
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The storage box utilizes vertical space by extending the bulge portion downward, accessing the volume above the air cleaner without requiring horizontal expansion. This dimensional approach allows the helmet storage capability to improve while maintaining clearance from the air cleaner located below.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The air cleaner is designed with a flexible top surface that can deform to accommodate the bulge portion. This dynamic adaptation allows the bulge portion to be enlarged for increased storage capability while the air cleaner's flexible surface prevents interference by conforming around the bulge.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4696594A1Straddled vehicle
Publication Date: 2026.02.18 YAMAHA MOTOR CO LTD
  • EP4696594A1 patent drawingFigure 1
  • EP4696594A1 patent drawingFigure 2
  • EP4696594A1 patent drawingFigure 3

AI summary

The present straddled vehicle (1) includes a seat (5), a storage box (21), a rear wheel (8), and a rear fender (7). The storage box (21) is disposed below the seat (5). The rear fender (7) is disposed below the storage box (21). The rear fender (7) is movable up and down together with the rear wheel (8). The storage box (21) includes a bulge portion (26), bulging downward, in a bottom surface thereof. The rear fender (7) includes a fender top portion (31) and a fender front portion (32). The fender top portion (31) is located uppermost in the rear fender (7). The fender front portion (32) extends forward and downward in a curved shape from the fender top portion (31). The bulge portion (26) is disposed above the fender front portion (32).