Pretensioned Coupling Actuation for Fast Fail-Safe Switching

Solution Overview

Problem

Existing coupling devices for motor vehicles require high-dynamic actuator drives, which are costly and space-intensive, and may fail to meet fail-safe requirements.

Innovation Solution

A coupling device with an actuating device featuring an intermediate position and a pretensioned spring mechanism, using a single spring to amplify the force of actuator elements, allowing for rapid switching without high dynamic requirements, and incorporating a self-locking actuator drive for cost-effectiveness and compactness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If a high-dynamic actuator drive is used to enable rapid connection and separation, then switching speed is improved, but cost and space requirements increase

Engineering Contradiction:

Improveswitching speedVSAvoidactuator drive complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The spring device is pretensioned in the intermediate position between base and switch positions, storing elastic energy in advance. This preliminary action enables the actuating device to rapidly transition between switching states without requiring a high-dynamic actuator drive, as the stored energy is released during the actual switching operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The actuating device utilizes a spring-based elastic element that dynamically stores and releases energy during operation. The spring device transitions between pretensioned and relaxed states, providing dynamic force multiplication that enables fast switching with a low-dynamic actuator drive.

Inventive Principle:

Principle #15Dynamics

2Speed

If a high-dynamic actuator drive is used to enable rapid connection and separation, then switching speed is improved, but cost increases

Engineering Contradiction:

Improveswitching speedVSAvoidmanufacturing cost

Core Design Contradiction:

SpeedVSEase of manufacture

Solution Approach 1:

The spring device is pretensioned in the intermediate position between base and switch positions, storing elastic energy in advance. This preliminary action enables the actuating device to rapidly transition between switching states without requiring a high-dynamic actuator drive, as the stored energy is released during the actual switching operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention replaces expensive high-dynamic actuator drives with a simple spring-based mechanism that uses inexpensive elastic elements. The spring device provides the necessary dynamic performance at a fraction of the cost of sophisticated actuator systems.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Speed

If a high-dynamic actuator drive is used to enable rapid connection and separation, then switching speed is improved, but space requirements increase

Engineering Contradiction:

Improveswitching speedVSAvoidactuator drive volume

Core Design Contradiction:

SpeedVSVolume of moving object

Solution Approach 1:

The spring device is pretensioned in the intermediate position between base and switch positions, storing elastic energy in advance. This preliminary action enables the actuating device to rapidly transition between switching states without requiring a high-dynamic actuator drive, as the stored energy is released during the actual switching operation.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The spring device is integrated within the compact actuating device structure, with the elastic element nested between actuator elements. This nested arrangement minimizes the overall volume of the actuating mechanism while maintaining the space-efficient benefits of spring-based dynamics.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 enables fast and reliable switching with reduced dynamic demands, minimizing system performance impact and costs, while ensuring fail-safe operation and reduced friction in all-wheel drives.

Implementation Method 1

the actuating device has a spring device... In the pretensioned state, the spring device can press the first actuator element in the first switching direction and/or the second actuator element in the second switching direction. The spring device thus amplifies the force of the two actuator elements

Methodology Applied

Scientific EffectElastic energy storage and release: Spring

Data Source

PatentUS12422003B2Coupling device with actuating device

Publication Date: 2025.09.23 SCHAEFFLER TECHNOLOGIES AG & CO KG

AI summary

The disclosure relates to a coupling device for coupling an input component to an output component so as to transmit a torque in a switchable manner. The coupling device includes a coupling designed to separate the input component and the output component in an open position and to connect these components in a closed position so as to transmit a torque. The coupling device further includes an actuating device, which can be moved between a base position and a switch position to adjust the coupling. The actuating device has an intermediate position which is located between the base position and the switch position, and, while in the intermediate position, the actuating device is pretensioned in the direction of the switch position and/or the base position.