CV Joint Outer Member Venting for Weld Length and Spatter Control

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Solution Overview

Problem

Existing manufacturing methods for outer joint members of constant velocity universal joints face issues with insufficient weld length due to heat-induced residual air pushing the welded portion radially outward and spatter entering the cup section, leading to degradation in durability and NVH properties.

Innovation Solution

The outer joint member design incorporates a ventilation hole and a welding spatter receiving groove, allowing for electron beam welding in a medium vacuum atmosphere, which secures the weld length and prevents spatter entry into the cup section.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If electron beam welding is performed in a medium vacuum state to enable industrial production, then productivity is improved, but heat during welding causes residual air to push the welded portion radially outward resulting in insufficient weld length

Engineering Contradiction:
ImproveproductivityVSAvoidweld length
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces a ventilation hole in the cup member before welding to communicate with the hollow cavity portion. This preliminary structural preparation allows residual air to escape through the ventilation hole during welding, preventing the air from pushing the welded portion radially outward and ensuring sufficient weld length is achieved while maintaining medium vacuum conditions for industrial productivity

Inventive Principle:
Principle #10Preliminary action

2Strength

If welding is performed to join cup member and shaft member, then strength is improved, but spatter enters the cup section causing degradation in durability and NVH properties

Engineering Contradiction:
Improveweld strengthVSAvoiddurability
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent introduces a welding spatter receiving groove in the shaft member that receives spatter generated during welding. This structural feature extracts and contains the harmful spatter away from the cup section, preventing spatter entry that would otherwise degrade durability and NVH properties, while allowing welding to proceed to achieve necessary joint strength

Inventive Principle:
Principle #2Taking out (Extraction)

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 configuration enhances weld strength and reliability, preventing durability and NVH property degradation by ensuring sufficient weld length and containing spatter, thus improving the quality and productivity of the joint.

Implementation Method 1

the cup member and the shaft member are welded by irradiating a light beam from an outer side to the abutment portion in a radial direction

Methodology Applied
Scientific EffectElectron beam welding: Electron Beam

Implementation Method 2

welding in a vacuum environment

Methodology Applied
Scientific EffectVacuum: Vacuum

Data Source

PatentEP3309420B1Outer joint member of constant-velocity universal joint
Publication Date: 2025.11.05 NTN CORP
  • EP3309420B1 patent drawingFigure 1
  • EP3309420B1 patent drawingFigure 2
  • EP3309420B1 patent drawingFigure 3a~3b

AI summary

Provided is an outer joint member (11, 112) of a constant velocity universal joint (10), including: a cup section (12, 121, 122) having track grooves (30) formed in an inner periphery of the cup section (12, 121, 122), which are engageable with torque transmitting elements (19, 23); and a shaft section (13) formed at a bottom portion of the cup section (12, 121, 122), the outer joint member being constructed by forming the cup section (12, 121, 122) and the shaft section (13) as separate members, and by bringing a cup member (12a, 12a1, 12a2) forming the cup section (12, 121, 122) and a shaft member (13a, 13a2) forming the shaft section (13) into abutment against each other and welding the cup member (12a, 12a1, 12a2) and the shaft member (13a, 13a2), the cup member (12a, 12a1, 12a2) and the shaft member (13a, 13a2) being brought into abutment against each other at respective joining end surfaces (50, 501, 502, 51, 511), to thereby form a hollow cavity portion (H), the cup member (12a, 12a1, 12a2) having, at an axial center of the cup member (12a, 12a2, 12a2), a ventilation hole (60) that communicates with the hollow cavity portion (H, H1), any one of the joining end surfaces (50, 501, 502) of the cup member (12a, 12a1, 12a2) and the joining end surface (51, 511) of the shaft member (13a, 13a2) having a welding spatter receiving groove (50a1, 51a, 51a1) formed on a radially inner side thereof.