Nut Glove Alignment in Semiconductor Devices

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Solution Overview

Problem

The existing semiconductor devices face challenges in achieving high precision alignment between the nut embedded in the nut glove and the mounting hole of the independent terminal, leading to difficulties in fixing external wires and terminals due to clearance issues between the projection parts and partition plates, which affects the reliability and integration density of IGBT modules.

Innovation Solution

The semiconductor device incorporates first and second projection parts on the nut glove and resin case, respectively, with tapers and stepped surfaces to securely fix the nut glove, eliminating rearward movement and enhancing alignment precision by applying a high compression load, ensuring precise positioning of the nut relative to the mounting hole.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the nut glove is inserted through the opening in the resin case, then the nut glove can be positioned below the independent terminal, but clearance is generated between the projection part and the partition plate, causing rearward movement and poor alignment

Engineering Contradiction:
Improvealignment precision between nut and mounting holeVSAvoidclearance between projection part and partition plate
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by forming tapers on the projection parts of the nut glove before insertion. These tapers enable the projection parts to be preliminarily engaged with the partition plate, preventing clearance generation and rearward movement during the insertion process. This preliminary engagement ensures precise alignment between the nut and mounting hole from the start.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent changes the geometric parameters of the projection parts by adding tapers with specific angles. This parameter change transforms the projection parts from flat surfaces to inclined surfaces, enabling them to be pressed against the partition plate and eliminate clearance. The taper geometry directly controls the compression load and alignment precision.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If the projection part has a perpendicular rear end face to the side surface, then the nut glove structure is simple, but clearance is generated and the nut glove cannot be fixed precisely

Engineering Contradiction:
Improvenut glove structureVSAvoidpositioning precision of nut glove
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The tapers on the projection parts serve as preliminary engagement features that guide the nut glove into correct positioning during insertion. This preliminary action eliminates the need for complex post-insertion adjustment mechanisms, maintaining structural simplicity while achieving high positioning precision through the geometric design of the tapers.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

By changing the geometry of the projection part from a perpendicular rear end face to one with tapers, the patent achieves better positioning precision without significantly increasing overall structural complexity. The taper angle and dimensions are optimized parameters that balance simplicity and precision.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If high compression load is applied to fix the nut glove, then alignment precision is improved, but the risk of damaging the resin case or nut glove increases

Engineering Contradiction:
Improvealignment precisionVSAvoidstructural integrity of resin case and nut glove
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The tapers create a dynamic compression mechanism where the compression load is applied progressively during insertion rather than abruptly. As the nut glove is inserted, the tapers naturally engage with the partition plate and apply increasing compression load, allowing the materials to deform gradually and avoid sudden stress that could cause damage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The taper angle is a critical parameter that controls the distribution and magnitude of compression load. By optimizing the taper angle, the patent achieves sufficient compression for high alignment precision while distributing the load in a way that prevents damage to the resin case or nut glove. The parameter change from perpendicular to tapered geometry fundamentally alters the stress distribution.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2738808B1Semiconductor device including a case in which a nut glove can be inserted
Publication Date: 2020.10.21 FUJI ELECTRIC CO LTD
  • EP2738808B1 patent drawingFigure 1(a)~1(c)
  • EP2738808B1 patent drawingFigure 2(a)~2(b)
  • EP2738808B1 patent drawingFigure 3(a)~3(c)

AI summary

A first projection part (10) is formed on a side surface of a nut glove (8). With respect to an insertion direction of the nut glove (8), first and second tapers (10a, 10b) are provided to the first projection part (10) in the forward insertion direction and the rearward insertion direction, respectively. The taper (10b) of the first proj ection part (10) provided in the rearward insertion direction is brought into pressure contact with an opening (7a) of a partition plate (6b) in a resin case (6), whereby the nut glove (8) is fitted in the resin case (6). This enables alignment between a nut (15) in the nut glove (8) and a mounting hole (16) of an independent terminal (5) with high precision. Further, a second projection part (11) is provided at an inlet of the opening (7a) of the resin case (6), and a top surface of a rear end of the nut glove (8) is brought into pressure contact with the second projection part (11). This further enables reliable fixing between the nut glove (8) and the resin case (6).