Weld Structure Gas Release Gutter for Differential Device

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Solution Overview

Problem

The existing weld structures for differential devices face issues with gas release during welding, leading to pressure buildup and potential defective holes, and require additional processes to prevent foreign objects from contaminating the transmission device, increasing production costs.

Innovation Solution

A weld structure with a communication passage that allows gas release during welding, blocked by a retaining pin or pinion shaft after assembly, preventing foreign objects from escaping and eliminating the need for additional assembly processes or cost increases.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a communication hole is provided to allow gas release during welding, then welding quality is improved by preventing defective holes, but foreign objects can escape through the hole and contaminate the transmission device

Engineering Contradiction:

Improvewelding qualityVSAvoidforeign object contamination

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by providing a gutter structure before welding that guides gas escape paths. The gutter is formed in advance on the press fit surface to direct gas away from the communication hole during welding, preventing foreign objects from being ejected while maintaining gas release functionality for weld quality

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent uses the gutter as an intermediary structure between the press fit surface and the communication hole. The gutter acts as a gas guide that mediates the gas flow path, directing it away from the communication hole opening, thus preventing foreign objects from escaping while maintaining the gas release function

Inventive Principle:

Principle #24Intermediary (Mediator)

2Object-affected harmful factors

If a communication hole is blocked to prevent foreign object ejection, then contamination is prevented, but gas pressure builds up during welding causing defective holes

Engineering Contradiction:

Improveforeign object ejectionVSAvoidwelding quality

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent segments the gas release function from the communication hole by introducing a gutter structure. The gutter provides an alternative gas escape path segmented from the communication hole, allowing gas to be released through the gutter while the communication hole remains blocked to prevent foreign object ejection

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The gutter serves as an intermediary gas release path that is separate from the communication hole. It mediates the gas release function, allowing gas to escape through the gutter structure while the communication hole can be blocked without compromising welding quality

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If a plug is inserted to block the communication hole, then foreign object ejection is prevented, but production cost increases due to additional processes

Engineering Contradiction:

Improveforeign object ejectionVSAvoidproduction cost

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent merges the gas release function with the gutter structure formed during press fitting. By combining the gas release function into the existing gutter geometry, no separate plug or additional blocking component is needed, eliminating extra assembly processes and reducing production costs

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The gutter structure serves multiple functions: it guides gas away from the communication hole during welding, prevents foreign object ejection, and eliminates the need for separate plug components. This multi-functionality reduces part count and assembly complexity, lowering production costs

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 weld structure effectively reduces pressure buildup and prevents contamination by releasing gas externally during welding, while ensuring the differential device remains sealed after installation, maintaining precision and reducing production costs.

Implementation Method 1

a high energy beam is radiated while a filler wire is supplied to a groove, and penetration welding that causes melt metal to reach the space is performed

Methodology Applied

Scientific EffectBeam welding: Laser Beam Welding

Implementation Method 2

heat input at the time of welding increases the pressure in the space at the back of the welding position

Methodology Applied

Scientific EffectHeat input: Heating

Data Source

PatentUS9933061B2Weld structure

Publication Date: 2018.04.03 SUBARU CORP

AI summary

A weld structure includes a fitting portion at which a first member and a second member are engaged, a weld portion at which the first member and the second member are welded together, and a space between the fitting portion and the weld portion. One of the first member and the second member has a communication passage whose one end is open to the space and whose other end is open to an outside at a position other than the space. The communication passage is blocked by an insertion member that has a predetermined function in addition to blocking the communication passage.