Webbing Take-Up Device with Integrated Switching Member
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Solution Overview
Problem
Existing webbing take-up devices have a high number of configuration components, which complicates the switching of force limiter loads and can result in noise and obstruction during operation.
Innovation Solution
A webbing take-up device with a spool, lock section, force limiter mechanism, and mounting member that includes a switching member and restriction section, where the restriction section applies a bias to the switching member using elastic deformation to reduce noise and component count, and the switching member can switch between rotation-restricted and rotation-enabled states to manage force limiter loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate displacement restriction member is provided to restrict switching member displacement, then the switching member can be properly constrained, but the number of configuration components increases
Solution Approach 1:
The mounting member integrates both the switching member mounting section and the displacement restriction function into a single component. The mounting member includes a body with a switching member mounting section and a displacement restriction section that protrudes from the body to engage with the switching member, thereby restricting its displacement. This merging eliminates the need for a separate displacement restriction member while maintaining reliable constraint of the switching member.
2Ease of operation
If the switching member is allowed to displace freely during state switching, then the switching operation is simpler, but noise occurs due to displacement within the mounting section
Solution Approach 1:
The mounting member combines the mounting function and displacement restriction function in one component. The displacement restriction section protrudes from the body and engages with the switching member to limit its displacement range, preventing excessive movement that causes noise while still allowing necessary switching motion.
Solution Approach 2:
The displacement restriction section acts as an intermediary between the mounting member body and the switching member. It provides controlled engagement that guides the switching member's motion, restricting displacement to acceptable ranges while allowing the switching operation to proceed smoothly without noise.
3Ease of manufacture
If multiple separate components are used for mounting and restricting the switching member, then each component can be optimized independently, but the overall device complexity increases
Solution Approach 1:
The mounting member is designed as an integrated component that combines the switching member mounting section and the displacement restriction section. The body provides the mounting section for attaching the switching member, while a protruding displacement restriction section engages with the switching member to limit its displacement. This integration reduces the total number of components while maintaining the ability to optimize each functional section during the design process.
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 number of components, suppresses noise from switching member displacement, and allows for efficient switching of force limiter loads, enhancing the device's operational reliability and simplicity.
Implementation Method 1
the restriction section applies a bias toward the switching member side using a recovery force arising as a result of elastic deformation in a direction away from the switching member
Data Source
AI summary
The present disclosure presents a webbing take-up device, which comprises: a spool; a lock section that is restricted from rotating at a time of a vehicle emergency so as to limit rotation of the spool in the pull-out direction; a force limiter mechanism that permits rotation of the spool in the pull-out direction at a force limiter load or greater when rotation of the spool in the pull-out direction with respect to the lock section is being limited; a switching member that switches a load value of the force limiter load by switching between a rotation-restricted state and a rotation-enabled state; and a mounting member that includes a switching member mounting section at which the switching member is disposed, and a restriction section that is engaged with the switching member so as to restrict displacement of the switching member disposed at the switching member mounting section.