Power Module Corner Press-Fit Anchors Eliminate Screw Fastening

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Solution Overview

Problem

Conventional power semiconductor device modules require additional mechanical screws or bolts for secure attachment to a PCB, which can introduce mechanical stresses, warpage, and installation complexities, and are costly and time-consuming.

Innovation Solution

The power semiconductor device module incorporates four novel mechanical corner press-fit anchors with barbed or catch features that secure into the housing, allowing for press-fit attachment to a PCB without the need for screws or bolts, thereby eliminating mechanical stresses and installation complexities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If screws or bolts are used to attach the module to the PCB, then mechanical strength is improved, but device complexity and installation time increase

Engineering Contradiction:

Improvemechanical strengthVSAvoiddevice complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The patent combines the mechanical anchoring function with the electrical terminal function into a single integrated component. The press-fit terminals serve dual purposes: providing electrical connection and serving as mechanical anchors to attach the module to the PCB, eliminating the need for separate screws or bolts.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the mechanical fastening function from the electrical terminal and relocates it to dedicated press-fit anchor points on the PCB. This allows the electrical terminals to focus solely on electrical connection while the anchors handle mechanical attachment, simplifying both components.

Inventive Principle:

Principle #2Taking out (Extraction)

2Strength

If screws or bolts are used to attach the module to the PCB, then mechanical strength is improved, but installation time and cost increase

Engineering Contradiction:

Improvemechanical strengthVSAvoidinstallation time

Core Design Contradiction:

StrengthVSLoss of time

Solution Approach 1:

The press-fit anchors are pre-positioned on the PCB during manufacturing, and the module is designed with corresponding pre-positioned electrical terminals that align with these anchors. This preliminary positioning eliminates the need for alignment and fastening operations during installation, reducing installation time to a simple press-fit operation.

Inventive Principle:

Principle #10Preliminary action

3Strength

If screws or bolts are used to attach the module to the PCB, then mechanical strength is improved, but mechanical stress and warpage increase

Engineering Contradiction:

Improvemechanical strengthVSAvoidmechanical stress

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical screw or bolt fastening system with a press-fit system that uses elastic deformation and friction to create a secure mechanical connection. This substitution eliminates the localized high stress concentrations and warpage associated with threaded fasteners.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Device complexity

If press-fit pins are used without mechanical anchors, then device complexity is reduced, but pull-out resistance decreases

Engineering Contradiction:

Improvedevice complexityVSAvoidpull-out resistance

Core Design Contradiction:

Device complexityVSForce

Solution Approach 1:

The patent enhances the press-fit terminals by adding lateral extending portions that extend perpendicular to the direction of the press-fit force. These lateral portions engage with corresponding features on the PCB to provide resistance against pull-out forces, adding a dimensional aspect to the mechanical connection.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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

The mechanical corner press-fit anchors provide substantial pull-out resistance, ensuring secure attachment without warpage or mechanical stress, reducing installation costs and time, and eliminating the need for additional fastening components.

Implementation Method 1

the press-fit pin portions being forced into corresponding holes in a PCB

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

the press-fit pin portions being forced into corresponding holes in a PCB

Methodology Applied

Scientific EffectDeformation: Deformation

Data Source

PatentUS10062621B2Power semiconductor device module having mechanical corner press-fit anchors

Publication Date: 2018.08.28 LITTELFUSE INC

AI summary

A power semiconductor device module includes a metal baseplate and a plastic housing that together form a tray. Power electronics are disposed in the tray. A plastic cap covers the tray. Electrical press-fit terminals are disposed along the periphery of the tray. Each electrical terminal has a press-fit pin portion that sticks up through a hole in the cap. In addition, the module includes four mechanical corner press-fit anchors disposed outside the tray. One end of each anchor is embedded into the housing. The other end is an upwardly extending press-fit pin portion. The module is manufactured and sold with the press-fit pin portions of the electrical terminals and the mechanical corner anchors unattached to any printed circuit board (PCB). The mechanical anchors help to secure the module to a printed circuit board. Due to the anchors, screws or bolts are not needed to hold the module to the PCB.