C-Pillar Retractor Mount Structure for Vibration and Crash Load Control

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Solution Overview

Problem

Existing side vehicle-body structures face challenges in suppressing vertical vibration of seatbelt retractors during vehicle travel and preventing deformation of retractor attachment portions during collisions, while also managing weight and manufacturing costs.

Innovation Solution

The implementation of a side vehicle-body structure that incorporates a vibration-damping joint portion to reduce vibration transmission to the seatbelt retractor and a gusset portion to support load input from the seatbelt during collisions, without increasing weight or manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a reinforcing member is provided to connect around the retractor attachment portion to increase rigidity, then vertical vibration suppression and deformation prevention are improved, but vehicle body weight and manufacturing costs increase

Engineering Contradiction:
Improveretractor attachment stabilityVSAvoidvehicle body weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The reinforcing member is divided into multiple sections with different rigidity characteristics. The first reinforcing section has higher rigidity to prevent deformation during collision, while the second reinforcing section has lower rigidity to reduce vibration transmission. This segmentation allows the structure to provide necessary support without excessive weight.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the reinforcing member are designed with different cross-sectional areas and material properties. The portion near the retractor attachment has larger cross-section for deformation prevention, while portions farther away have smaller cross-sections. This local quality variation optimizes the balance between strength and weight.

Inventive Principle:
Principle #3Local quality

2Strength

If the plate thickness of the reinforcing member is increased to suppress deformation, then structural strength is improved, but manufacturing costs and weight increase

Engineering Contradiction:
Improveretractor attachment strengthVSAvoidmanufacturing cost
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The reinforcing member uses varying plate thicknesses in different sections rather than uniform thickness. The first reinforcing section has greater thickness for high-strength requirements, while the second section has reduced thickness where full strength is not needed, lowering material costs.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reinforcing member's cross-sectional area is locally optimized based on load requirements. Areas experiencing higher stresses during collision have larger cross-sections, while areas with lower stress requirements have smaller cross-sections, reducing overall material usage and cost.

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

This solution effectively suppresses vertical vibration of the seatbelt retractor during vehicle travel and prevents deformation of the retractor attachment portion during collisions, all while maintaining cost-effectiveness and avoiding excessive weight increase.

Implementation Method 1

when the vibration caused by the road-surface input from the rear suspension (the vibration inputted to the rear-suspension attachment portion via the rear suspension from the rear wheel during the vehicle traveling) is transmitted to the reinforcing member, this vibration is damped by the vibration-damping joint portion

Methodology Applied
Scientific EffectVibration damping: Damping

Data Source

PatentEP4140832B1Side vehicle-body structure of vehicle
Publication Date: 2025.01.22 MAZDA MOTOR CORP
  • EP4140832B1 patent drawingFigure 1
  • EP4140832B1 patent drawingFigure 2
  • EP4140832B1 patent drawingFigure 3

AI summary

There are provided a side panel (2) constituting a vehicle side face (1) at a higher level than a damper attachment portion (19) suspending a rear wheel, a retractor (42) fixed to a cabin-inside face of the side panel, a frame member (4) forming a closed-cross section (4S) extending vertically in corporation with the side panel, and a reinforcing member (50) fixed to the side panel. The reinforcing member comprises a retractor attachment portion (Na, Ba) to attach the retractor, a gusset portion (52) to partition the closed-cross section of a C pillar reinforcement vertically, and a vibration-damping joint portion (53) joined to the side panel via a vibration-damping material. Herein, the reinforcing member is formed integrally by a member which is configured to be continuous over a range of the retractor attachment portion, the gusset portion and the vibration-damping joint portion.