Webbing Take-up Device Locking Unit Noise Reduction
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Solution Overview
Problem
The existing webbing take-up devices, particularly the WSIR mechanism, suffer from noise generation due to unnecessary movement of the W pawl during normal operation, as its turning is not regulated, leading to collisions with the inertia mass.
Innovation Solution
A webbing take-up device with a locking unit that includes a rotational acceleration detecting unit, comprising a second rotating body, an inertial mass body, a biasing means, and a retaining portion, which prevents unnecessary movement of the rotation transmission member by engaging and disengaging it with the first rotating body based on predetermined acceleration, thereby regulating the spool's rotation and reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the W pawl is allowed to move freely during normal operation, then the locking unit can respond to acceleration events, but unnecessary movement and noise occur during normal spool rotation
Solution Approach 1:
The W pawl's engagement state is dynamically changed based on operating conditions: it is disengaged during normal operation to prevent noise, and engaged during acceleration events to enable locking function. The rotational acceleration detecting unit dynamically controls the W pawl's engagement state through the rotation transmission member.
Solution Approach 2:
The rotation transmission member acts as an intermediary between the rotational acceleration detecting unit and the W pawl. It transmits rotational motion during acceleration events to engage the W pawl, while allowing the W pawl to remain disengaged during normal operation, thus mediating between the detection mechanism and the locking component.
2Object-generated harmful factors
If the W pawl is retained disengaged from the first rotating body, then noise is reduced during normal operation, but the locking response may be delayed during acceleration events
Solution Approach 1:
The W pawl is preliminarily positioned in a disengaged state during normal operation to eliminate noise. The rotational acceleration detecting unit is continuously monitoring, and upon detecting acceleration, immediately actuates the rotation transmission member to engage the W pawl, ensuring rapid response without prolonged delay.
Solution Approach 2:
During acceleration events, the system rushes through the engagement process by directly transmitting rotational motion through the rotation transmission member to quickly engage the W pawl, minimizing the time the system spends in a transitional state and reducing locking response time.
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
Effectively prevents unnecessary movement and noise by ensuring the rotation transmission member remains engaged only during high acceleration events, maintaining the spool's rotation regulation and reducing noise during normal operation.
Implementation Method 1
an inertial mass body having a pressing portion and provided at the second rotating body, and rotating in a direction opposite to the predetermined direction relative to the second rotating body
Implementation Method 2
a biasing means provided at the second rotating body to bias the inertial mass body in the predetermined direction whereby the inertial mass body pressure contacts the rotation transmission member
Data Source
AI summary
A webbing take-up device comprising a spool and a locking unit having a locking unit main body having a rotational acceleration detecting unit, wherein the rotational acceleration detecting unit comprises a second rotating body; a rotation transmission member provided at the second rotating body; an inertial mass body having a pressing portion and provided at the second rotating body; a biasing means provided at the second rotating body; and a retaining portion provided at the second rotating body to pinch the rotation transmission member together with the inertial mass body biased by the biasing means, thereby retaining the rotation transmission member in a state in which the rotation transmission member does not engage with the first rotating body, and to release retention of the rotation transmission member when relative rotation is produced between the second rotating body and the inertial mass body.