Outer Joint Member Manufacturing via Electron Beam Welding
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Solution Overview
Problem
The manufacturing of outer joint members for constant velocity universal joints faces challenges such as burrs generated during friction press-contact, leading to increased manufacturing costs and difficulties in ultrasonic flaw detection, and poor welding quality due to gas pressure variations during laser or electron beam welding.
Innovation Solution
A manufacturing method involving electron beam welding with pre-heating and cooling of the cup and shaft members, ensuring equal dimensions for the fitting portion, and evacuating the internal space to reduce cycle time and enhance quality, while allowing for standardization and cost reduction through common use of cup and shaft members with varied specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If friction press-contact is used to join cup member and shaft member, then the joining strength is improved, but burrs are generated on the joining portion increasing manufacturing cost and complexity
Solution Approach 1:
The harmful burrs generated during friction press-contact are removed through turning or milling operations. This extraction of the defective portion restores the surface quality and enables subsequent ultrasonic flaw detection, though it increases manufacturing steps and cost.
Solution Approach 2:
The friction heat generated during press-contact, which causes burr formation and surface defects, is utilized to improve the joining strength through localized heat treatment and metallurgical bonding, while the harmful burrs are subsequently removed.
2Manufacturing precision
If burrs are removed through turning or milling, then the surface quality is improved for ultrasonic flaw detection, but the manufacturing cycle time and cost increase
Solution Approach 1:
The cup member and shaft member are subjected to heat treatment and finishing operations before joining to ensure they meet dimensional and surface quality specifications in advance, reducing the need for post-joining corrective operations.
Solution Approach 2:
Ultrasonic flaw detection is used to replace destructive inspection methods and detect internal defects non-destructively, ensuring quality without requiring additional material removal or processing steps.
3Productivity
If laser welding or electron beam welding is used to join members, then the joining speed and productivity are improved, but gas pressure variations cause poor welding quality
Solution Approach 1:
The cup section is evacuated to create a vacuum environment during electron beam welding, eliminating gas pressure variations and atmospheric interference that would otherwise cause welding defects. This ensures high welding quality while maintaining the productivity benefits of beam welding.
4Adaptability or versatility
If cup member and shaft member are manufactured with varied specifications, then the adaptability to different vehicle types is improved, but the standardization and cost reduction opportunities are reduced
Solution Approach 1:
The outer joint member is divided into separate cup member and shaft member components that can be manufactured independently with different specifications according to vehicle type requirements, then joined through friction press-contact or welding. This segmentation enables both customization and standardization.
Solution Approach 2:
The cup member is designed with a universal joining interface that can accommodate different shaft member specifications, allowing the same cup member design to be used across multiple vehicle applications while maintaining adaptability through shaft member variations.
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 method strengthens the welded portion, improves quality, reduces welding costs, and enhances productivity and standardization, enabling reliable ultrasonic flaw detection and stable hardness adjustment for the welded region.
Implementation Method 1
electron beam welding with pre-heating and cooling of the cup and shaft members
Implementation Method 2
pre-heating and cooling of the cup and shaft members
Implementation Method 3
pre-heating and cooling of the cup and shaft members
Implementation Method 4
evacuating the internal space to reduce cycle time and enhance quality
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
Provided is a manufacturing method for an outer joint member (11) of a constant velocity universal joint (10), the manufacturing method comprising: forming a cup member (12a) and a shaft member (13a) of medium carbon steel; performing, as manufacturing steps, a machining step and a heat treatment step on the cup member (12a) after integrally forming a tubular portion (12a1) and a bottom portion (12a2) of the cup member (12a) by forging, the machining step comprising forming a joining hole (50) in a thickness of the bottom portion (12a2) to prepare the cup member (12a) as a finished component; performing, as manufacturing steps, a machining step and a heat treatment step on the shaft member (13a), the machining step for the shaft member (13a) comprising forming a joining outer surface (51) on an end portion of the shaft member (13a) to be joined onto the bottom portion (12a2) of the cup member (12a) to prepare the shaft member (13a) as a finished component; fitting the joining hole (50) of the cup member (12a) as the finished component and the joining outer surface (51) of the shaft member (13a) as the finished component to each other; and welding a fitting portion (60) between the joining hole (50) and the joining outer surface (51) through irradiation of a beam from an inner side of the cup member (12a), a diameter of the fitting portion (60) being set to an equal dimension for each joint size.