Through Anchor Positioning During Resin Molding
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Solution Overview
Problem
Existing seatbelt guide anchors face issues with positional displacement during resin molding, leading to poor positioning and increased sliding resistance and pulling force when webbing is inserted or pulled out.
Innovation Solution
A through anchor design featuring a metal main body with a through hole, a piece that covers the inner peripheral edge and forms a slide contact, and a covering portion molded integrally with the piece, including a groove with inclined faces forming obtuse angles to prevent displacement and reduce sliding resistance, and a piece configuration that tilts to reduce pulling force by increasing the sliding surface area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If clearance is provided between the groove forming rib and the outer peripheral edge of the guide piece, then interference with the guide piece during molding is prevented, but positional displacement of the guide piece occurs
Solution Approach 1:
A positioning protrusion is introduced as an intermediary element between the guide piece and the mold. This protrusion fits into a corresponding positioning groove in the mold, acting as a mediator that enables precise positioning without requiring clearance between the groove forming rib and guide piece outer edge.
2Manufacturing precision
If the piece is firmly fixed to the main body portion, then positioning during molding is improved, but sliding resistance increases
Solution Approach 1:
The groove portion is designed with different local qualities: the bottom surface has a relatively flat region for stable positioning, while the side surfaces are inclined to reduce friction. This local differentiation allows the groove to provide both firm positioning and low sliding resistance in different areas.
Solution Approach 2:
The groove portion parameters are optimized by setting specific angle ranges (45-60 degrees for side surfaces) and depth ratios. These parameter changes enable the groove to simultaneously achieve good positioning during molding and reduced sliding resistance for webbing movement.
3Stability of the object's composition
If the groove portion is made deeper, then positioning stability is improved, but pulling force on webbing increases
Solution Approach 1:
The groove portion depth is optimized within specific parameters (depth between 0.5-2.0mm, depth-to-width ratio between 0.2-0.5). These controlled parameter changes ensure sufficient positioning stability while limiting the increase in pulling force on the webbing.
Solution Approach 2:
The groove portion uses different local qualities in different regions: the bottom surface provides positioning stability through a flat region, while the inclined side surfaces reduce friction and pulling force. This local differentiation resolves the contradiction between stability and force.
Data Source
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AI summary
In a through anchor, a side face on a piece side of a groove portion is configured by a piece side inclined face, with the piece side inclined face being inclined in a direction such that an angle formed between the piece side inclined face and a slide face of the piece is an obtuse angle. During molding of a molded portion, an apex portion of a rib of a mold is disposed on or abuts the piece side inclined face of the piece. Movement of the piece in a length direction thereof is accordingly suppressed by the rib of the mold. The molded portion can accordingly be molded with the piece in a well-positioned state by injecting a resin material for the molded portion into the mold in this state.