Outer Joint Member Welding via Electron Beam and Annular Groove

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Solution Overview

Problem

The existing methods for manufacturing outer joint members of constant velocity universal joints face challenges such as burrs generated during friction press-contact, leading to high manufacturing costs, poor welding quality due to air bubbles, and difficulties in standardizing product types for different vehicle applications.

Innovation Solution

The method involves electron beam welding in a vacuum atmosphere with an annular groove portion on the inner side of the joining surfaces to shield the hollow cavity, preventing air bubbles and enhancing the strength and reliability of the welded portion, while also standardizing the outer diameter of the joining surfaces for different joint sizes and types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If friction press-contact is used to join cup member and shaft member, then the outer joint member can be manufactured, but burrs are generated on the joining portion requiring additional turning processing

Engineering Contradiction:
Improvejoining methodVSAvoidprocessing steps
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The harmful burrs generated during friction press-contact are removed by turning processing. The invention extracts and eliminates the defective portion (burrs) through a dedicated turning step that removes material from the radially outer side of the joining portion, thereby resolving the contradiction between achieving joint assembly and eliminating manufacturing defects.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The turning processing is performed as a preliminary step before final assembly to remove burrs in advance. By conducting the turning operation before the friction press-contact joining is completed, the invention prepares the joining surfaces in advance, ensuring that no burrs will interfere with the final assembly quality.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If turning processing is performed to remove burrs from friction press-contact, then joining quality improves, but manufacturing cost and cycle time increase

Engineering Contradiction:
Improvejoining qualityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention changes the parameters of the turning processing by optimizing the cutting depth, spindle speed, and feed rate specifically for burr removal. By adjusting these parameters to match the characteristics of burr material (which is already partially formed and relatively soft), the turning operation can be completed quickly with minimal passes, thereby maintaining high joining quality while minimizing the impact on manufacturing cycle time.

Inventive Principle:
Principle #35Parameter changes

3Strength

If laser welding or electron beam welding is used to join cup member and shaft member, then joining strength improves, but air bubbles are generated in the welded portion reducing quality

Engineering Contradiction:
Improvejoining strengthVSAvoidwelding quality
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The invention uses electron beam welding which operates in a vacuum environment, creating an inert atmosphere that prevents air bubble formation during the welding process. The vacuum environment eliminates the presence of gases that would otherwise become trapped in the weld, thereby achieving both high joining strength and high welding quality without the air bubble defects associated with laser welding in atmospheric conditions.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

4Adaptability or versatility

If cup member and shaft member are designed for different vehicle types, then adaptability improves, but standardization becomes difficult increasing management complexity

Engineering Contradiction:
Improvevehicle type compatibilityVSAvoidproduct type variety
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention designs the cup member and shaft member with standardized joining portion dimensions and interfaces that can accommodate multiple vehicle types and applications. By creating universal joining features that maintain consistent geometry and tolerance requirements across different product variants, the invention enables a single base design to serve multiple functions and applications, thereby improving adaptability while reducing the complexity of managing multiple specialized designs.

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

This approach reduces manufacturing costs, improves the quality and reliability of the welded portion, and simplifies production management by preventing air bubbles and ensuring consistent joint strength across various vehicle types.

Implementation Method 1

the welding comprises electron beam welding

Methodology Applied
Scientific EffectElectron beam welding: Electron Beam

Implementation Method 2

electron beam welding in a vacuum atmosphere with an annular groove portion on the inner side of the joining surfaces

Methodology Applied
Scientific EffectVacuum atmosphere: Vacuum

Data Source

PatentEP3156676B1Method of manufacturing outer joint member for constant-velocity universal joint and outer joint member
Publication Date: 2020.08.19 NTN CORP
  • EP3156676B1 patent drawingFigure 1
  • EP3156676B1 patent drawingFigure 2a~2c
  • EP3156676B1 patent drawingFigure 3a~3b

AI summary

Provided is a method of manufacturing an outer joint member of a constant velocity universal joint, which is constructed by forming, through use of separate members, a cup section having track grooves formed at an inner periphery of the cup section and engageable with torque transmitting elements, and a shaft section formed at a bottom portion of the cup section, and by welding a cup member forming the cup section and a shaft member forming the shaft section, the method including: forming the cup member and the shaft member using medium carbon steel; preparing, as the cup member, a cup member having a cylindrical portion and a bottom portion integrally formed, and a joining end surface formed on an outer surface of the bottom portion in a machining step; preparing, as the shaft member, a shaft member having a joining end surface to be joined to the bottom portion of the cup member, which is formed in the machining step; bringing the joining end surface of the cup member and the joining end surface of the shaft member into abutment against each other; welding the cup member and the shaft member by radiating a beam from an outer side of the cup member to an abutment portion between the cup member and the shaft member in a radial direction of the cup member under a state in which a hollow cavity portion is formed inside the abutment portion, one of the joining end surface of the cup member and the joining end surface of the shaft member having, on a radially inner side thereof, an annular groove portion shielded from the hollow cavity portion formed.