Circuit Assembly Terminal Layout Against Resin Molding Deformation

Solution Overview

Problem

The risk of control terminal deformation and short-circuiting during resin molding due to injection pressure in circuit assemblies, where control terminals are connected to busbars using solder and held by a thermoplastic resin holding member.

Innovation Solution

The circuit assembly includes control terminals with specific side faces and spaces formed by projections in the molding die, preventing resin intrusion and maintaining terminal position, and a resin holding member that covers these terminals to suppress deformation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If control terminals are placed as insert articles in a die for injection molding, then the holding member can be molded as one piece with the control terminals, but the injection pressure may cause the control terminals to incline or deform

Engineering Contradiction:

Improvemolding process integrationVSAvoidcontrol terminal positioning accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies preliminary action by forming spaces around the control terminals before the injection molding process. These spaces are created in advance to prevent resin intrusion that would cause terminal deformation. The spaces act as preventive measures prepared beforehand to counteract the harmful effects of injection pressure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent introduces spaces as intermediary regions between the control terminals and the molten resin. These spaces serve as buffer zones that mediate the interaction between the rigid control terminals and the pressurized resin, preventing direct contact and subsequent deformation of the terminals during molding.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If control terminals are held by a thermoplastic resin holding member, then the terminals are fixed and insulated, but resin may flow into the space between the die and control terminal causing inclination or deformation

Engineering Contradiction:

Improveelectrical insulation and terminal fixationVSAvoidcontrol terminal geometric stability

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by pre-forming spaces around the control terminals before injection molding. These spaces are created in advance to prevent resin intrusion that would cause terminal deformation. The spaces act as preventive measures prepared beforehand to counteract the harmful effects of injection pressure.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies preliminary anti-action by creating spaces that preemptively counteract the harmful effect of resin intrusion. These spaces are designed to resist the injection pressure and prevent the resin from reaching and deforming the control terminals, thus neutralizing the potential harm before it occurs.

Inventive Principle:

Principle #9Preliminary anti-action

3Measurement precision

If control terminals are positioned by surface-contact with the die, then positioning is achieved, but injection pressure may cause resin to flow into the contact space causing terminal deformation

Engineering Contradiction:

Improveterminal positioning precisionVSAvoidinjection pressure effects

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent introduces spaces as intermediary regions between the control terminals and the molten resin. These spaces serve as buffer zones that mediate the interaction between the rigid control terminals and the pressurized resin, preventing direct contact and subsequent deformation of the terminals during molding.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies preliminary action by forming spaces around the control terminals before the injection molding process. These spaces are created in advance to prevent resin intrusion that would cause terminal deformation. The spaces act as preventive measures prepared beforehand to counteract the harmful effects of injection pressure.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12412877B2Circuit assembly and electrical junction box

Publication Date: 2025.09.09 SUMITOMO WIRING SYSTEMS LTD

AI summary

A circuit assembly includes a plurality of electronic components; a plurality of control terminals electrically connected to the plurality of electronic components; and a holding member having insulating properties and holds the plurality of control terminals, wherein the control terminals serve as insert articles that form one piece with the holding member that is made of a resin, the control terminals each include: in a partial portion of the control terminal, an exposed face that is exposed from the holding member; a contact face that is located opposite to the exposed face and is in contact with the holding member; a first side face located between the exposed face and the contact face; and a second side face located between the exposed face and the contact face, and a first space formed lateral to the first side face, and a second space formed lateral to the second side face.