Webbing Take-Up Device Guide Section Phase Alignment
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Solution Overview
Problem
Existing webbing take-up devices face difficulties in easily fitting the fitting shaft section into the fitting hole section due to mismatched phases, requiring cumbersome alignment operations.
Innovation Solution
The webbing take-up device incorporates a guide section on either the adapter or the spool, which uses inclined surfaces to facilitate relative rotation and alignment of the adapter, allowing the fitting shaft to be easily inserted into the fitting hole even when phases are mismatched, by generating a pressing force that adjusts the adapter's position for proper alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a non-circular fitting shaft and fitting hole are used to prevent relative rotation, then the connection strength and rotational constraint are improved, but the ease of assembly deteriorates due to phase alignment requirements
Solution Approach 1:
The guide section performs preliminary action by guiding the fitting shaft into the fitting hole along a predetermined path before the final engagement. The inclined surface of the guide section pre-aligns the phases of the fitting shaft and fitting hole, allowing the non-circular shapes to engage properly without requiring manual phase alignment during assembly.
Solution Approach 2:
The guide section acts as an intermediary element between the fitting shaft and fitting hole. It mediates the engagement process by providing a transitional path that accommodates the non-circular shapes, allowing them to align and engage automatically during insertion without requiring precise external alignment.
2Reliability
If precise phase alignment is required for fitting shaft and fitting hole, then the rotational constraint is improved, but the manufacturing precision requirements worsen
Solution Approach 1:
The guide section with its inclined surface performs preliminary alignment action during the assembly process. Instead of requiring high manufacturing precision for phase alignment, the guide section automatically performs the alignment function mechanically during insertion, reducing the precision requirements for the fitting shaft and fitting hole manufacturing.
Solution Approach 2:
The guide section enables the fitting shaft and fitting hole to self-align during assembly. The inclined surface guides the insertion process, allowing the non-circular shapes to automatically find their correct rotational positions without requiring external alignment tools or procedures.
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
This solution enables effortless fitting of the fitting shaft into the fitting hole without requiring precise phase alignment, enhancing the assembly process and ensuring proper operation of the webbing take-up device.
Implementation Method 1
a spring being provided inside of the housing, one end of the spring being connected to the housing and another end of the spring being connected to the adaptor, an urging force of the spring in the take-up direction being increased by the adapter being rotated in a pull-out direction
Implementation Method 2
a guide section being provided on at least one of the adapter or the spool, the guide section pressing the adapter in the pull-out direction or the guide section being pressed by the fitting shaft section in the pull-out direction when a leading end side of the fitting shaft section intrudes into the fitting hole section in a state in which the phase of the fitting shaft section diverges from the phase of the fitting hole section
Data Source
AI summary
When an attempt is made to insert a fitting-shaft section into a fitting-hole section where phases of the fitting-shaft section of a spring-screw and the fitting-hole section of an adapter about a central-axis line of a spool-body are not matched, shaft-section-side inclined-surfaces formed at shaft-section-side protrusions abut to hole-section-side inclined-surfaces formed at hole-section-side protrusions, so the shaft-section-side inclined-surfaces press the hole-section-side inclined-surfaces in such a direction inclined in a pull-out direction to a projecting-direction of a shaft-section body from a flange section. The adapter upon receiving a pressing force generated by this pressing at the hole-section-side inclined-surfaces rotates in the pull-out direction, thereby aligning phases of the fitting-hole section and the fitting-shaft section about the central-axis line such that each shaft-section-side protrusion inserts into a gap between the hole-section-side protrusions adjacent to each other, and the fitting-shaft section fits into the fitting-hole section.