Motor Vehicle Subframe Reinforcement via Local Brackets

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Solution Overview

Problem

The existing subframe designs for motor vehicles with 5-link axles often require long subframes or strong curves to accommodate the suspension links, leading to potential weak points, especially in curved areas, which can compromise structural robustness and necessitate additional reinforcement.

Innovation Solution

The subframe mounts for control arms are designed as two consoles, one supported on the longitudinal section and the other on the transverse section, with rubber-metal sleeve bearings and fastening screws forming a diagonal support, and additional stiffening plates are used to reinforce the curved sections, thereby enhancing structural integrity without increasing material thickness or cross-sectional area.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the subframe is designed with strong curves to accommodate suspension links, then the structural robustness is improved, but the curvature area creates weak points requiring additional reinforcement

Engineering Contradiction:
Improvestructural robustnessVSAvoidweak points in curved area
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies local reinforcement through brackets positioned specifically at the curved section of the subframe's longitudinal beam. Instead of uniformly strengthening the entire subframe, the reinforcement is localized to the critical curved area where weak points occur, using brackets that provide additional structural support precisely where needed.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The reinforcement system is segmented into discrete brackets that are independently mounted to the subframe. Each bracket acts as a separate reinforcement element that can be individually positioned and attached to the curved section, allowing targeted strengthening without modifying the entire subframe structure.

Inventive Principle:
Principle #1Segmentation

2Strength

If the material thickness or cross section is increased for general reinforcement, then the structural strength is improved, but the device complexity and manufacturing effort increase

Engineering Contradiction:
Improvestructural strengthVSAvoidreinforcement structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The reinforcement is achieved through separate, discrete brackets rather than modifying the entire subframe structure. This segmentation allows the reinforcement function to be added independently without redesigning the whole subframe, reducing overall device complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The brackets act as intermediary elements between the subframe and the suspension links. Instead of directly modifying the subframe to increase its strength, the brackets serve as intermediate reinforcement structures that distribute and support the loads in the curved area.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of operation

If the subframe is made very long to accommodate the rear upper guide link, then the link positioning is improved, but the subframe complexity and material usage increase

Engineering Contradiction:
Improvelink positioningVSAvoidsubframe structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

Rather than uniformly extending the subframe length, the patent uses localized brackets at specific positions to support the suspension links. This allows the subframe to maintain a more compact overall length while still providing proper link positioning through targeted local support structures.

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 approach provides effective local reinforcement of the subframe, enhancing its structural rigidity and stability in curved areas with minimal additional effort, effectively addressing the weak points and ensuring robustness without the need for general reinforcement.

Implementation Method 1

Rubber-metal sleeve bearings are firmly connected via a fastening screw

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

vibration-damping subframe bearings

Methodology Applied
Scientific EffectVibration damping: Damping

Implementation Method 3

the base walls and their side walls can be welded to the longitudinal beams

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 4

Rubber-metal sleeve bearings are firmly connected via a fastening screw

Methodology Applied
Scientific EffectMechanical fastening: Mechanical Fastener

Data Source

PatentEP2836418B1Device for reinforcing a supporting sub-frame
Publication Date: 2015.12.02 AUDI AG
  • EP2836418B1 patent drawingFigure 1
  • EP2836418B1 patent drawingFigure 2

AI summary

The invention relates to a device for reinforcing a supporting sub-frame for motor vehicles which is made up of two longitudinal spars (30) and at least one transverse spar (32, 34), wherein by means of radially projecting fixed mountings (36, 38) the links (14, 16, 20, 22) of wheel suspensions on both sides are articulated on the longitudinal spars (30) by means of rubber/metal sleeve bearings, and wherein at least in an articulation region of a link (14) the longitudinal spars (30) have a curvature of in particular approximately 90° with a longitudinally extending section (30b) and a transversely extending section (30c). According to the invention the mountings (36, 38) are formed as two brackets, of which one is supported on the longitudinally extending section (30b) of the longitudinal spars (30) and the other is supported on the transversely extending section (30c).