Motor Vehicle Step Plate with Pivoting Impact Absorption

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Solution Overview

Problem

Motor vehicle footboards face a dilemma in needing sufficient rigidity to support user weight while also complying with pedestrian impact regulations that require a soft contact zone for shock absorption.

Innovation Solution

A running board device with a movable plate articulated around a vertical axis, supported by a structural element, featuring return means to revert to a deployed position and stop means to limit displacement, positioned below the lower wall with a distance of 0.5-5 mm, allowing the plate to advance over half the cavity's depth for enhanced support and impact absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the shield is made rigid to support user weight, then the strength is improved, but the ability to absorb impact energy deteriorates

Engineering Contradiction:
ImprovestrengthVSAvoidimpact energy absorption
Core Design Contradiction:
StrengthVSLoss of energy

Solution Approach 1:

The shield is divided into a fixed part and a movable plate that can pivot independently. The movable plate is segmented from the main shield structure and connected via an articulation point, allowing it to move separately to absorb impact energy while the fixed part maintains overall structural strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shield incorporates a movable plate that can dynamically pivot around an articulation point during impact events. This dynamic movement allows the shield to adapt its rigidity - remaining rigid during normal use for strength, but capable of controlled movement during pedestrian impact to absorb energy.

Inventive Principle:
Principle #15Dynamics

2Loss of energy

If the shield is made flexible to absorb impact energy, then the ability to absorb impact energy is improved, but the strength to support user weight deteriorates

Engineering Contradiction:
Improveimpact energy absorptionVSAvoidstrength
Core Design Contradiction:
Loss of energyVSStrength

Solution Approach 1:

The shield is divided into a fixed part and a movable plate that can pivot independently. The movable plate is segmented from the main shield structure and connected via an articulation point, allowing it to move separately to absorb impact energy while the fixed part maintains overall structural strength.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Only the lower portion of the shield (the movable plate) is made flexible with impact-absorbing characteristics, while the upper portion remains rigid. This local differentiation allows the shield to have soft contact zones for pedestrian safety while maintaining overall structural integrity for supporting user weight.

Inventive Principle:
Principle #3Local quality

3Loss of energy

If a movable plate is added to provide impact absorption, then the ability to absorb impact energy is improved, but the device complexity increases

Engineering Contradiction:
Improveimpact energy absorptionVSAvoiddevice complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The shield incorporates a movable plate that can dynamically pivot around an articulation point during impact events. This dynamic movement allows the shield to adapt its rigidity - remaining rigid during normal use for strength, but capable of controlled movement during pedestrian impact to absorb energy.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The shield's rigidity parameter is made variable through the movable plate mechanism. During normal conditions, the plate remains in a position providing rigid support. During impact, the plate can change its angular position around the articulation point to absorb energy, effectively changing the structural parameters in response to loading conditions.

Inventive Principle:
Principle #35Parameter changes

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

The solution provides both the necessary rigidity for user weight support and flexibility during impacts, effectively meeting the conflicting requirements of supporting users and absorbing pedestrian impact energy.

Implementation Method 1

the movable plate 8 and the rear wall 13 are typically made up of elements from assembled-welded sheet metal or formed by bending from a single metal part to obtain the general shape of a bracket. This allows mounting of the mobile plate 8 on the structural element 9, 11, 12 without conflict with the bodywork element 1 and constitutes sufficient clearance to allow movement of the mobile plate 8 without obstacle.

Methodology Applied
Scientific EffectDeformation: Deformation

Data Source

PatentEP3069936B1Device forming a step of a motor vehicle
Publication Date: 2017.11.22 RENAULT SA
  • EP3069936B1 patent drawingFigure 1~2
  • EP3069936B1 patent drawingFigure 3~4
  • EP3069936B1 patent drawingFigure 5~7

AI summary

The invention relates to a step device comprising a body panel (1) of a motor vehicle, a cavity (2) formed in the body panel (1) delimited by a lower wall (3) forming a support surface for the front part of a user's foot (4). The device includes a movable platform (8) hinged to a structural element (9, 11, 12) of the vehicle, between a deployed position below the lower wall (3) in the direction of the body panel (1), and a retracted position opposite the body panel (1), the movement of the movable platform (8) to the retracted position being achieved under the stress of the body panel (1) undergoing deformation following an impact.