Suspension Sub Frame Impact Absorption via Cross Member

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Solution Overview

Problem

Existing suspension sub frame structures face challenges in achieving effective impact absorption while maintaining structural rigidity without increasing vehicle weight, as rigid components can lead to improper bending or breakage under load, and current designs may compromise impact absorption performance.

Innovation Solution

A suspension sub frame structure featuring an extension frame with lower rigidity than the suspension sub frame, connected via a cross member that reinforces the joint area between the two frames, allowing for effective impact absorption and reduced risk of bending or breakage, while maintaining structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the tower member is formed rigidly to suppress bending deformation, then the impact absorption performance is improved, but the vehicle weight increases

Engineering Contradiction:
Improveimpact absorption performanceVSAvoidvehicle weight
Core Design Contradiction:
ReliabilityVSWeight of moving object

Solution Approach 1:

The patent applies local quality by providing a reinforcing portion only at the specific location where the bent portion of the longitudinal member faces the longitudinal extension portion of the lower arm, rather than making the entire tower member rigid. This localized reinforcement suppresses bending deformation at the critical connection point while keeping the rest of the structure lightweight.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent segments the reinforcement function by separating the reinforcing portion from the overall tower member structure. The reinforcing portion is provided as a distinct element that addresses the specific weakness at the connection point between the extension frame and sub frame, allowing the rest of the tower member to remain lightweight.

Inventive Principle:
Principle #1Segmentation

2Strength

If the extension frame is directly connected to the sub frame, then the rigidity is improved, but bending or breakage occurs at the connection portion under impact load

Engineering Contradiction:
Improvestructural rigidityVSAvoidconnection portion integrity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent introduces a reinforcing portion as an intermediary element between the bent portion of the longitudinal member and the longitudinal extension portion of the lower arm. This reinforcing portion acts as a mediator that distributes and transfers loads, preventing direct stress concentration at the connection point and thereby avoiding bending or breakage while maintaining rigidity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs composite structural design by combining the longitudinal member with a reinforcing portion at the connection area. This composite approach creates a stronger connection that resists bending and breakage under impact loads while maintaining the overall lightweight design of the extension frame.

Inventive Principle:
Principle #40Composite materials

3Reliability

If the extension frame has lower rigidity to promote impact absorption, then the impact load absorption is improved, but the connection portion becomes vulnerable to bending

Engineering Contradiction:
Improveimpact load absorptionVSAvoidconnection portion strength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent applies local quality by providing a reinforcing portion only at the specific connection point where strength is needed, while the rest of the extension frame maintains lower rigidity to promote impact absorption. This localized reinforcement ensures connection integrity without compromising the overall impact absorption capability of the extension frame.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3626586B1Suspension sub frame structure
Publication Date: 2021.06.02 MAZDA MOTOR CORP
  • EP3626586B1 patent drawingFigure 1
  • EP3626586B1 patent drawingFigure 2
  • EP3626586B1 patent drawingFigure 3

AI summary

A suspension sub frame structure comprises a suspension sub frame 110 configured to extend substantially in a vehicle longitudinal direction and supporting a suspension member of a front wheel, an extension frame 130 configured to extend forwardly from a front end of the suspension sub frame 110 and having lower rigidity against a load applied substantially in the vehicle longitudinal direction than the suspension sub frame 110, and a cross member 150 configured to extend in a vehicle width direction on an inward side, in the vehicle width direction, of the both frames 110, 130, wherein the cross member 150 is joined to the both frames 110, 130 at a joint area Z which is formed continuous substantially in the vehicle longitudinal direction.