Vehicle Hood Lifting Joint With Bowden Cable Reset

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Solution Overview

Problem

Existing active front hoods in motor vehicles require significant follow-up costs for repairs due to pyrotechnic actuators, are difficult to reset without tools, and can obstruct repairs, leading to increased effort and costs.

Innovation Solution

A lifting system with a lifting joint, pre-tensioned spring elements, and actuators that move the body hood between normal and collision positions, allowing for easy reset and integration in limited vehicle space, using indirect actuation via Bowden cables or hydraulic lines.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pyrotechnic actuators are used to raise the hood, then the hood can be reliably moved to collision position, but repair costs increase and the system becomes difficult to reset

Engineering Contradiction:
Improvereliability of hood movement to collision positionVSAvoidease of reset without tools
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

A Bowden cable is introduced as an intermediary mechanical element to transmit force from the actuator to the hood lifting mechanism. This allows the actuator to be positioned remotely and enables tool-free reset operation while maintaining reliable hood movement to collision position.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces pyrotechnic actuators with an electric actuator coupled with a Bowden cable mechanical transmission system. This substitution maintains the reliability of hood movement while enabling easy reset without tools, as the electric actuator can be remotely controlled and the Bowden cable provides mechanical advantage.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If pyrotechnic actuators are used, then the hood can be activated, but follow-up costs and repair efforts increase considerably

Engineering Contradiction:
Improveactivation capabilityVSAvoidrepair cost and effort
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent employs a Bowden cable system that can be easily replaced or reset without requiring expensive pyrotechnic components. The cable-based mechanism allows for lower-cost repairs and maintenance compared to pyrotechnic actuators, reducing follow-up costs while maintaining activation capability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Object-affected harmful factors

If the hood is raised to create distance from components, then collision protection is improved, but the hood obstructs driver view and prevents repairs

Engineering Contradiction:
Improvecollision protectionVSAvoiddriver view and repair access
Core Design Contradiction:
Object-affected harmful factorsVSEase of operation

Solution Approach 1:

The patent implements a dynamically controllable hood system that can be raised to collision position for protection and then easily returned to normal position for driving and repair operations. The electric actuator with Bowden cable enables smooth, controlled movement between positions, allowing the hood to adapt to different operational requirements.

Inventive Principle:
Principle #15Dynamics

4Power

If the actuator is positioned close to the lifting joint, then mechanical efficiency is high, but installation space in the vehicle is insufficient

Engineering Contradiction:
Improvemechanical efficiencyVSAvoidinstallation space
Core Design Contradiction:
PowerVSVolume of moving object

Solution Approach 1:

The patent uses a Bowden cable to transmit mechanical force from a remotely positioned actuator to the lifting joint. This allows the actuator to be installed in available space away from the lifting joint while still delivering sufficient mechanical force through the cable, effectively utilizing three-dimensional space within the vehicle structure.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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

Enables cost-effective, tool-free reset of the hood, reduces installation space requirements, and allows predictive activation to prevent collisions, minimizing repair costs and ensuring safe operation.

Implementation Method 1

The lifting joint (9) also comprises at least one pre-tensioned spring element (17) for moving the hood part (12) from the normal position into the collision position

Methodology Applied
Scientific EffectElastic potential energy: Elasticity

Implementation Method 2

The release actuator (10) and/or the return actuator (11) acts indirectly on the lifting joint (9), in particular via a Bowden cable (23, 26)

Methodology Applied
Scientific EffectMechanical force transmission: Mechanical Force

Data Source

PatentEP4631798A1Lifting system for a vehicle body hood
Publication Date: 2025.10.15 VOLKSWAGEN AG
  • EP4631798A1 patent drawingFigure 1~3
  • EP4631798A1 patent drawingFigure 4~5
  • EP4631798A1 patent drawingFigure 6~7

AI summary

Lifting system for moving a body hood (2) of a motor vehicle (1) from a normal position into a collision position, with • a lifting joint (9) which comprises a hood part (12) configured for connection to the body hood (2) and a body part (13) connected for connection to another section of a body of the motor vehicle (1), wherein the hood part (12) and the body part (13) are movably connected to one another via a joint system, and at least one prestressed spring element for moving the hood part (12) from the normal position into the collision position. • a trigger actuator (10) for moving the body hood (2) from the normal position into the collision position or for releasing a locking system of the lifting joint (9), which locks the body hood (2) in the normal position, and • a return actuator (11) for moving the body hood (2) from the collision position into the normal position.The release actuator (10) and/or the return actuator (11) acts indirectly, in particular via a Bowden cable, on the lifting joint (9).