Insert Mold Cavity Design for Resin Flow Control
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Solution Overview
Problem
During insert molding, the case of the sensor unit extending radially outward from the magnetic convergence ring holder is prone to deformation due to resin pressure, which is not effectively addressed in existing technologies.
Innovation Solution
The mold design is modified to reduce the flow resistance of resin flowing through side channels, allowing it to fill these channels before the upper channels, thereby reducing the force applied to the second circuit portion and minimizing deformation. This is achieved by making the distance between the side surfaces of the second circuit portion and the corresponding side walls longer than the distance between the upper surface and the upper wall, ensuring the resin flows into the side channels first, thus reducing the pressure on the second circuit portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If insert molding is used to integrate the sensor unit and housing, then manufacturing efficiency and integration are improved, but the case of the sensor unit is deformed by resin pressure
Solution Approach 1:
The mold cavity is segmented into multiple injection channels (upper channels and side channels) that inject resin into different regions of the housing simultaneously. This segmentation allows the resin to fill the mold in a controlled sequence, reducing concentrated pressure on the sensor unit case and preventing deformation while maintaining integration benefits.
2Productivity
If resin is injected into the mold with sensor unit placed, then the housing is formed, but the resin pressure deforms the electronic unit
Solution Approach 1:
The mold is designed with side channels positioned to be filled with resin before the upper channels. This preliminary action ensures that the side regions of the housing are formed first, providing structural support before the upper resin flow exerts pressure on the sensor unit case, thereby maintaining shape stability during the molding process.
Solution Approach 2:
The injection parameters are optimized by controlling the flow resistance in different channels. The side channels are designed with lower flow resistance compared to upper channels, causing resin to preferentially fill side regions first. This parameter change in flow resistance distribution prevents excessive pressure buildup on the electronic unit while maintaining productive molding.
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 configuration allows for the integral molding of the electronic unit and housing as a single component while suppressing deformation of the electronic unit during the molding process, ensuring a robust and watertight housing structure.
Implementation Method 1
Insert molding is a process in which a resin is injected into a mold with the member placed in the mold, and the member and the housing are integrally molded into a single component
Data Source
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AI summary
A mold for insert molding, which houses an electronic unit including a first circuit portion and a second circuit portion protruding from the first circuit portion, is prepared. The mold includes an upper wall surface facing an upper surface of the second circuit portion and side wall surfaces facing side surfaces of the second circuit portion. The flow resistance of a resin flowing through a space between each side surface of the second circuit portion and the corresponding side wall surface is lower than that of the resin flowing through a space between the upper surface of the second circuit portion and the upper wall surface. Then, the electronic unit is placed in the mold. A distance between each of the side surfaces of the second circuit portion and the corresponding side wall surface is longer than a distance between the upper surface of the second circuit portion and the upper wall surface. Then, the resin is injected into the mold in which the electronic unit has been placed. Thus, the electronic unit and the housing in which the electronic unit is housed are integrated with each other. Further, there is provided a housing structure that includes an electronic unit including a first circuit portion having an annular shape and a second circuit portion protruding radially outward from the first circuit portion, and a housing in which the electronic unit is housed, the housing being integral with the electronic unit, wherein the second circuit portion comprises a main body portion extending radially outward from the first circuit portion. The housing structure is further provided with a tapered portion protruding from the main body portion in a direction in which a central axis of the first circuit portion extends or a terminal extending radially outward from the main body portion and an extending portion extending to a position radially outward of the terminal.