Webbing Take-Up Device Retaining Member Simplifies Structure
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Solution Overview
Problem
Existing webbing take-up devices have complex strength maintaining structures and high output requirements for prevention release sections, making them cumbersome and inefficient.
Innovation Solution
A webbing take-up device with a simplified strength maintaining structure, where a single retaining member supports the drive device and movable member, allowing efficient transmission of drive force and reducing the output of the prevention release section by using a deformation amount changing member and displacement prevention member to manage the force limiter member's deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a closure member is used to close off the support member, then the movable member is retained and allowed to move, but the joint strength between the support member and closure member must be high, resulting in a complex strength maintaining structure
Solution Approach 1:
The retaining member integrates multiple functions: it retains the drive device, retains the movable member while allowing its movement, and transmits drive force. This merging of functions eliminates the need for separate closure members and complex joint strength maintaining structures.
Solution Approach 2:
The retaining member serves multiple purposes simultaneously: structural support, movement constraint, and force transmission. This multi-functionality reduces the overall number of components and simplifies the strength maintaining structure.
2Strength
If the prevention member is designed to withstand the rotation force from the force limiter member, then the force limiter member is prevented from rotating in the pull-out direction, but the prevention member has large weight and requires high output from the prevention release section
Solution Approach 1:
The pawl-ratchet mechanism replaces the need for a heavy prevention member. The pawl engages with ratchet teeth on the force limiter member to prevent rotation, utilizing mechanical interlocking rather than relying on the weight and strength of a large prevention member.
Solution Approach 2:
The pawl is designed to be temporarily displaced by the gas generator during force limiter actuation, then returns to its blocking position. This allows the prevention mechanism to be lightweight while still providing sufficient prevention capability when needed.
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 simplifies the strength maintaining structure and reduces the power output of the prevention release section, leading to a more compact, lightweight, and cost-effective webbing take-up device.
Implementation Method 1
a drive device (92) that is disposed with respect to the movable member (104) on a straight line along a movement direction of the movable member, and that moves the movable member (104) by a drive force that is output toward a movable member side
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
In a webbing take-up device 10, a base cartridge 94 receives pressure of gas generated by an MGG 98, load from a piston 104 that is moved by the pressure of the gas, and reaction force acting on the MGG 98 when gas has been ejected from the MGG 98. This enables strength retention with respect to the above-described pressure, load, and reaction force to be simplified.