Straddle-Type Vehicle Frame Using Battery Case as Structural Bridge

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Solution Overview

Problem

Existing straddle-type vehicles face challenges in reducing vehicle weight while maintaining sufficient rigidity, particularly due to the long and heavy side frames connected by multiple bridges.

Innovation Solution

The design incorporates a down frame with side frames that extend rearward and rise obliquely, featuring a pivot bracket and suspension bracket, and coupling the side frames via a battery case instead of bridges, thereby shortening the frame length and enhancing rigidity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the pair of side frames are bent sharply behind the battery case and connected by multiple bridges, then the rigidity of the vehicle body frame is ensured, but the overall length of the side frames becomes long and the vehicle becomes heavier

Engineering Contradiction:
Improverigidity of vehicle body frameVSAvoidvehicle weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The battery case is integrated to directly connect the pair of side frames, merging the function of the battery housing with the function of a structural connector. This eliminates the need for separate bridges while maintaining frame rigidity, thereby reducing vehicle weight.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The battery case serves multiple functions: it houses the battery and simultaneously acts as a structural connector between the side frames. This multi-functionality reduces the number of separate components needed, simplifying the overall structure and reducing weight while maintaining rigidity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Shape

If the pair of side frames are bent sharply behind the battery case, then the structural configuration is achieved, but the overall length of the side frames becomes long

Engineering Contradiction:
Improveconfiguration of side framesVSAvoidlength of side frames
Core Design Contradiction:
ShapeVSLength of moving object

Solution Approach 1:

The battery case is positioned and shaped to directly connect the side frames, merging the structural support function into the battery housing. This integration allows the side frames to be shorter while maintaining the necessary structural configuration and rigidity.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4530172A1Battery arrangement of a straddle-type vehicle
Publication Date: 2025.04.02 SUZUKI MOTOR CORP
  • EP4530172A1 patent drawingFigure 1
  • EP4530172A1 patent drawingFigure 2
  • EP4530172A1 patent drawingFigure 3

AI summary

A straddle-type vehicle (1) includes a down frame (12) extending downward from a head pipe (11) at a vehicle body front portion, a pair of side frames (13) connected to a lower portion of the down frame (12), and a battery case (31) installed inside the pair of side frames (13). The pair of side frames (13) extend rearward from the down frame (12) and rise up obliquely rearward at a front side of the battery case (31). A pivot bracket (41) is provided midway in an extending direction of the pair of side frames (13), a swing arm (25) being supported by the pivot bracket (41). A suspension bracket (45) is provided at a rear portion of the pair of side frames (13), a rear suspension (28) being supported by the suspension bracket (45). The pair of side frames (13) are coupled to each other via the battery case.