Vehicle Lower Structure With Inner Protectors for Battery Collision Clearance

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Solution Overview

Problem

When a gearbox is disposed with its rear portion in a floor tunnel during a front collision, the battery units on either side of the tunnel may come into contact with the gearbox, potentially causing damage to the battery units.

Innovation Solution

A lower vehicle structure is designed with a gearbox positioned such that its rear portion is within the floor tunnel, a propeller shaft extending from the gearbox to the rear wheel, and battery units positioned below the floor panels, with inner protectors covering the front end of the battery units' inner side surfaces to prevent direct contact with the gearbox.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the gearbox is disposed with the rear portion in the floor tunnel to increase collision stroke, then the collision load absorption is improved, but the battery units may come into contact with the gearbox during front collision

Engineering Contradiction:
Improvecollision load absorptionVSAvoidbattery unit damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a protective cover as an intermediary component between the gearbox and battery units. This cover prevents direct contact during collision while allowing the gearbox to move backward for load absorption, thus resolving the contradiction between collision performance and battery protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective cover is designed as a segmented structure that can deform independently during collision. This segmentation allows the cover to absorb impact forces while maintaining the gearbox's ability to move backward, balancing collision absorption with battery unit protection.

Inventive Principle:
Principle #1Segmentation

2Volume of moving object

If the battery units are disposed close to the gearbox to save space, then the vehicle structure compactness is improved, but the risk of battery damage during collision increases

Engineering Contradiction:
Improvevehicle structure compactnessVSAvoidbattery unit damage risk
Core Design Contradiction:
Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The protective cover serves as a mediator that enables close positioning of battery units and gearbox while preventing harmful contact during collision. This allows space optimization without compromising safety.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective cover is pre-installed on the battery units to provide beforehand cushioning against potential collision damage. This allows the battery units to be positioned closer to the gearbox while maintaining protection during front collision events.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Data Source

PatentEP4005842B1Lower structure of vehicle
Publication Date: 2025.02.12 MAZDA MOTOR CORP
  • EP4005842B1 patent drawingFigure 1
  • EP4005842B1 patent drawingFigure 2
  • EP4005842B1 patent drawingFigure 3

AI summary

[Task] To suppress damage to battery units at the time of a front collision of a vehicle even when a part of a gearbox is disposed in a floor tunnel. [Solution] A lower structure of a vehicle includes a transmission 4 disposed in a floor tunnel 10, a rear propeller shaft 9 that transmits power from the transmission 4 to rear wheels 7, and left and right battery units 40L and 40R disposed on the left and right sides of the floor tunnel 10, in which a rear portion (transfer 4a) of the transmission 4 is disposed in proximity to the portions on the front side and the upper side of the battery units 40L and 40R, and inner protectors 70L and 70R that cover inner side surface portions 45L and 45R in the vehicle width direction of the battery units 40L and 40R from the inner side in the vehicle width direction are mounted to the front end portions of the inner side surface portions 45L and 45R.