Stator Base Member Projection for Molded Motor Resin Injection
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Solution Overview
Problem
In the manufacturing of molded motors, the high fastening pressure applied during the formation of the mold resin portion can damage the base member, which is critical for supporting the stator and circuit board.
Innovation Solution
A projection is designed on the base member's radially outer side, which is squashed by the second mold during the resin injection process, reducing the load on the base member and preventing damage. This method involves supporting the base member with a first mold and joining it with a second mold to create a cavity, where molten resin is injected, with the second mold pressing against the projection to distribute the load effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high fastening pressure is applied to the pair of molds during resin injection, then the mold resin portion is properly formed with good waterproofness, but the base member may be damaged under the load
Solution Approach 1:
A projection is added to the base member that serves as an intermediary load-bearing element. During resin injection, the second mold presses against this projection rather than directly against the main body of the base member. The projection acts as a mediator that distributes and redirects the molding load, preventing direct stress concentration on the base member while still enabling proper resin formation for waterproofness.
Solution Approach 2:
The projection is pre-formed on the base member before the resin injection process. This preliminary structural feature is designed in advance to specifically handle the load that will be applied during molding. By preparing this load-distributing element beforehand, the base member is protected from damage when the high fastening pressure is subsequently applied during resin injection.
2Manufacturing precision
If the base member is supported by a first mold and pressed by a second mold during resin injection, then the mold resin portion is accurately formed, but the base member is subjected to excessive load that may cause damage
Solution Approach 1:
The projection serves as a dedicated intermediary contact point between the second mold and the base member. This allows the molding process to proceed with accurate pressure application for forming the mold resin portion, while the projection mediates the mechanical stress to prevent base member damage. The projection is positioned and sized to optimize both molding precision and load distribution.
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 approach effectively reduces the likelihood of base member damage and ensures accurate molding of the mold resin portion, maintaining the structural integrity of the motor components while preventing water ingress and electrical malfunctions.
Implementation Method 1
the second mold is pressed against a projection, the projection being provided on an upper surface of the base member and on a radially outer side with respect to the circuit board in plan view
Implementation Method 2
the projection is squashed. Thus, the load applied to the base member is reduced
Data Source
AI summary
A stator unit included in a motor includes a base member, an armature, a circuit board, and a mold resin portion. The base member extends substantially perpendicularly to a vertically extending center axis. The armature and the circuit board are positioned above the base member. The circuit board is electrically connected to the armature. The mold resin portion covers the armature and the circuit board. In a process of forming the mold resin portion, the base member is supported by a first mold. Then, the first mold is joined to a second mold such that a cavity is provided therebetween. In this step, the second mold is pressed against a projection provided on an upper surface of the base member and on a radially outer side with respect to the circuit board in plan view. The projection thus pressed is squashed. Subsequently, molten resin is injected into the cavity.