Steering Wheel Horn Switch Link Plate Mechanism
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Solution Overview
Problem
Conventional horn switch devices for steering wheels face design limitations due to the narrowing of the gap between the airbag module and the steering wheel, leading to potential horn non-operation and increased failure rates, as well as aesthetic issues with the inside of the steering wheel being visible.
Innovation Solution
A horn switch device utilizing a link plate assembly that enables vertical movement of the airbag module, allowing for a seesaw operation mechanism to reduce the gap and ensure proper horn contact, thereby improving design freedom and operational quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the airbag module is pressed to operate the horn, then the horn spring acts as a hinge point and the airbag module inclines with an arc trace, but the gap between the airbag module and the steering wheel is narrowed
Solution Approach 1:
A link plate assembly is introduced as an intermediary mechanism between the airbag module and the horn contact points. The link plate assembly includes a first link plate connected to the airbag module, a second link plate connected to the steering wheel, and a third link plate connecting the first and second link plates. This intermediary mechanism transforms the pressing motion into proper contact motion while maintaining adequate gap, resolving the contradiction between reliable horn operation and maintaining gap distance.
2Reliability
If the gap is considerably increased for gap insurance, then the operational reliability improves, but the inside of the steering wheel becomes visible in appearance
Solution Approach 1:
The link plate assembly serves as a mediator that allows the system to achieve reliable horn operation without requiring excessive gap. By introducing this intermediate mechanism, the patent enables precise control of the contact motion while maintaining aesthetic appearance, resolving the contradiction between reliability and appearance.
3Strength
If the airbag module is restricted by the horn spring, then the horn spring provides elastic support, but the airbag module traces an arc with long radius and small angle
Solution Approach 1:
The link plate assembly acts as an intermediary that decouples the elastic support function from the operational motion constraint. The horn spring continues to provide elastic support through the link plate assembly, while the link plates guide the motion along a more favorable trajectory, improving ease of operation without sacrificing elastic support.
Solution Approach 2:
The link plate assembly introduces dynamic motion control, transforming the static arc-trace constraint into a more flexible operational path. The link plates enable the airbag module to move with greater freedom while still achieving reliable contact, applying the dynamics principle to improve operational ease.
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 reduces the gap between the steering wheel and airbag module, prevents horn non-operation, enhances design flexibility, and lowers production failures, while maintaining a sleek appearance without the need for additional shielding.
Implementation Method 1
an airbag module (12) mounted in an inner region of a steering wheel (10) to perform pressing and restoring operations while being elastically supported by a plurality of horn springs (11)
Implementation Method 2
it is possible to implement a new method for operating a horn switch in a vertical direction in which the horn switch can be operated by vertically moving the airbag module through an operation of the link plate assembly using the lever principle
Data Source
AI summary
A horn switch device for a steering wheel may include an airbag module mounted in an inner region of the steering wheel to perform pressing and restoring operations while being elastically supported by a plurality of horn springs, a link plate assembly mounted on a lower surface of the airbag module and including a plurality of link plates to facilitate a seesaw movement, a module-side horn contact point positioned at the fixed end portion of each link plate and toward the outside of the airbag module, and a wheel-side horn contact point positioned below the module-side horn contact point. A horn operation is produced when the wheel-side horn contact point contacts with the module-side horn contact point.