Switchable Coupling for Vehicle Auxiliaries with Self-Holding Locking
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Solution Overview
Problem
Existing switchable couplings for passenger cars require continuous electrical power to maintain switching states, leading to increased fuel consumption and energy waste, and fail to reliably disconnect the drive element from the power take-off element at low speeds, causing potential shocks and component stress.
Innovation Solution
A switchable coupling with an electrically, mechanically, pneumatically, or hydraulically actuated activation system that uses a switching member and reset elements to establish a friction-fit or shape-fit connection between the drive and power take-off elements, allowing the coupling to maintain the switching state without continuous energy input and ensuring reliable disconnection at low speeds, thereby preventing shocks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrically actuated magnetic coil is used to switch the coupling, then the switching state can be maintained, but continuous electrical power is required leading to increased fuel consumption
Solution Approach 1:
The coupling system uses self-holding locking elements that automatically maintain the coupled state without requiring continuous external energy input. The locking elements engage with the drive element and power take-off element through mechanical interlocking, allowing the system to sustain its switching state autonomously once activated.
Solution Approach 2:
The magnetic coil is activated only periodically during the switching transition phase, not continuously. The activation system applies magnetic force briefly to move the locking elements into position, then deactivates, allowing the mechanical locking mechanism to maintain the state without further energy input.
2Power
If centrifugal weights are used to produce friction-fit connection, then torque transfer is enabled, but no reliable disconnection device is provided below specific speed
Solution Approach 1:
The locking elements are designed to dynamically respond to rotational speed changes. At low speeds, spring force keeps the locking elements disengaged. As speed increases, centrifugal force overcomes the spring force, automatically engaging the locking elements for torque transfer. The system naturally transitions between engaged and disengaged states based on operational conditions.
Solution Approach 2:
Spring elements provide a counteracting force to the centrifugal force acting on the locking elements. This spring force ensures reliable disengagement at low speeds by maintaining the locking elements in a retracted position, while centrifugal force dominates at higher speeds to enable engagement.
3Power
If friction coupling is used for torque transfer, then connection is established, but friction forces are insufficient at low speeds
Solution Approach 1:
The coupling system is segmented into multiple functional components: locking elements for mechanical engagement, friction surfaces for torque transfer, and spring elements for force balancing. This segmentation allows each component to perform its specific function optimally, with locking elements providing structural connection and friction surfaces providing torque transfer capability.
Solution Approach 2:
The system merges positive mechanical locking with friction-based torque transfer in a single integrated mechanism. The locking elements provide both the structural connection and the friction contact surfaces, combining two torque transfer methods to ensure reliable operation across all speed ranges.
4Reliability
If centrifugal bodies enter operative connection at different speeds, then coupling is established, but shocks and component stresses occur
Solution Approach 1:
Spring elements are pre-positioned to provide cushioning force during the engagement process. As the locking elements approach the drive element, the spring force gradually increases, absorbing冲击 and reducing the stress of sudden engagement. This cushioning effect prevents shock loads on the component surfaces during coupling establishment.
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 eliminates the need for continuous energy input, reduces fuel consumption, and ensures reliable torque transfer and disconnection, minimizing component stress and energy waste while maintaining efficient operation.
Implementation Method 1
an electrically actuated magnetic coil
Implementation Method 2
produce an operative connection between the drive element and the power take-off element by friction fit and/or shape fit
Implementation Method 3
counter to the force of one or more reset elements, such as springs
Data Source
AI summary
A switchable coupling, in particular for vehicle auxiliary assemblies, is provided. The coupling includes an actuating system actuated electrically, mechanically, pneumatically or hydraulically between a driving element and an output element, and a switching element movable between switching start and end positions counter to the force of one or more resetting elements upon actuation of the actuating system. In the end position, the switching element connects the driving and output elements such that the output element and an auxiliary coupling connected thereto rotate with the driving element. After deactuation, locking bodies located on the auxiliary coupling produce an connection between the driving and output elements which continues to conduct torque between the driving and output elements. The connection is interrupted only when the rotational speed of the driving element falls below a limit value. The coupling does not require a permanent supply of power in the open or closed state.