Webbing Take-Up Device Tilt Restriction Mechanism
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Solution Overview
Problem
Existing webbing take-up devices experience tilt issues when the actuation member is activated, leading to potential misalignment and inefficiencies in the rotation of the spool and lock mechanism.
Innovation Solution
The webbing take-up device incorporates a tilt restricting portion on the rotation body that projects towards the sensor holder, restricting tilt by contacting the sensor holder and preventing misalignment, along with columnar stopper and actuation shafts to limit the actuation range and support the actuation member, and multiple tilt restricting portions spaced around the rotation body to effectively suppress tilt.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the lock arm is supported in an eccentric position on the lock clutch body to enable actuation range, then the emergency lock mechanism can be activated by sudden webbing pull-out, but a rotational moment is generated in the axial direction causing tilt of the lock clutch body
Solution Approach 1:
A tilt restricting portion is introduced as an intermediary element between the lock clutch body and the sensor holder. This mediator prevents direct transmission of rotational moments that cause tilt, while allowing the emergency lock mechanism to function normally through eccentric actuation.
Solution Approach 2:
The tilt restricting portion provides preliminary counter-action against the rotational moment generated during lock arm actuation. By preemptively restricting tilt before it occurs, the system maintains stability during emergency lock activation without compromising the eccentric actuation mechanism.
2Ease of operation
If the rotation body is allowed to tilt during actuation, then the actuation member can engage with the sensor holder, but misalignment occurs leading to inefficient operation
Solution Approach 1:
The tilt restricting portion performs preliminary alignment of the rotation body before the actuation member engages with the sensor holder. By pre-establishing proper alignment, the system ensures both easy engagement and high precision operation without requiring post-engagement adjustments.
Data Source
AI summary
The present invention provides a webbing take-up device that can effectively suppress tilt of a rotation body when an actuation member has been actuated. In a webbing take-up device, tilt restricting portions are provided at a V gear. The tilt restricting portions are provided at a radial direction inner side than a place of engagement between a W pawl and ratchet teeth of a sensor holder and project further toward a sensor holder side than an end surface at the sensor holder side, which end surface is at the outer side in the radial direction than the place of engagement. For this reason, tilt of the V gear with respect to its axial direction can be restricted.