Steering Wheel Horn Switch Spacing Mechanism
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Solution Overview
Problem
The existing steering wheel designs with horn switch mechanisms suffer from resin powder generation due to contact between the slider and movable side contact, leading to potential electrical communication disturbances when the airbag is pressed down.
Innovation Solution
Incorporating a spacing portion between the movable side contact and the slider, formed by rearward bending of the plate material or using a band-shaped contact terminal, ensures that the slider and movable side contact remain spaced, preventing resin powder generation and maintaining electrical communication.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the slider is indirectly contacted with the cap member via the movable side contact, then the number of components is reduced and configuration is simplified, but resin powders are generated due to contact between the slider and movable side contact, causing potential electrical communication disturbances
Solution Approach 1:
The patent introduces a spacing portion as an intermediary structural feature between the slider and movable side contact. This spacing portion acts as a mediator that prevents direct contact between the resin slider and metal movable side contact, thereby eliminating resin powder generation while maintaining the simplified component configuration. The spacing portion is formed by bending the movable side contact to create a gap that prevents harmful friction and material degradation.
2Device complexity
If the slider is indirectly contacted with the cap member via the movable side contact, then the configuration is simplified, but electrical communication between the movable side contact and supporting member may be disturbed due to accumulated resin powders forming an insulating layer
Solution Approach 1:
The patent applies preliminary anti-action by proactively preventing resin powder generation through the spacing portion design. By eliminating the source of contamination before it can occur, the system prevents future electrical communication failures. The spacing portion is designed in advance to maintain permanent clearance, preventing resin accumulation that would otherwise form insulating layers and disrupt electrical contacts during airbag activation.
3Force
If the movable side contact and slider are in contact, then force transfer from the airbag apparatus is enabled, but resin powder generation occurs due to friction and contact between the slider and movable side contact
Solution Approach 1:
The spacing portion serves as an intermediary structural feature that enables force transfer while preventing harmful contact. The cap member transfers force to the movable side contact, which then transfers force to the slider through the spacing portion without direct contact between the slider and movable side contact. This mediator approach maintains the necessary mechanical force transmission for horn activation while eliminating friction-induced resin powder generation.
Data Source
AI summary
A steering wheel has an airbag apparatus mounted on a core metal via a horn switch mechanism for activating a horn device. The horn switch mechanism includes a supporting member that is formed of an electrically conductive material, supported on the core metal, and extends rearward, a slider that is formed of an insulating resin material, is disposed outside the supporting member to be slidable with respect to the supporting member, and urged rearward by an urging member, a cap member that is formed of an insulating resin material and covers at least a rear end of each of the supporting member and the slider, and a movable side contact that is formed of an electrically conductive metal material and disposed between the cap member and the slider. The horn switch mechanism is configured to activate the horn device.