CV Joint Outer Member Welding Around Center Segregation
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Solution Overview
Problem
The manufacturing of outer joint members for constant velocity universal joints via friction press-contact and welding faces challenges such as burr generation, distorted shapes, increased cycle time, and reduced welding quality due to center segregation, leading to strength and quality issues in the welded portion.
Innovation Solution
The method involves forming a cup member and a shaft member with joining end surfaces that are welded to form an annular welded portion, positioning the welded portion radially outer to the center segregation, and using electron beam welding to prevent burr formation and ensure deep penetration, thereby avoiding interference from center segregation and enhancing welding quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If friction press-contact is used to join cup member and shaft member, then joining is achieved, but burrs are generated and distorted shapes occur leading to increased cycle time
Solution Approach 1:
The patent replaces the mechanical friction press-contact joining method with electron beam welding. This substitution eliminates the generation of burrs and distorted shapes associated with friction pressing, while achieving secure joining of the cup member and shaft member. The electron beam welding process provides precise control over the joining operation, reducing cycle time by eliminating post-processing steps for burr removal.
Solution Approach 2:
The patent changes the joining method from mechanical friction press-contact to electron beam welding, fundamentally altering the process parameters. This parameter change eliminates the harmful effects of burr generation and shape distortion while maintaining effective joining. The electron beam welding parameters (beam current, voltage, scanning speed) are optimized to achieve deep penetration without generating surface defects.
2Manufacturing precision
If center segregation is present in the blank, then material structure is formed, but welding quality deteriorates due to interference with welded portion
Solution Approach 1:
The patent extracts or removes the harmful center segregation from the welding zone by positioning the welded portion radially outward from the center segregation location. The electron beam welding is applied at a location that avoids the segregated impurities, thereby preventing their interference with the welded portion. This spatial separation ensures that the welding quality is not compromised by the presence of center segregation in the blank material.
Solution Approach 2:
The patent performs preliminary positioning of the cup member and shaft member to ensure that the joining location is radially outward from the center segregation. This preliminary action of correct positioning before welding prevents the welded portion from overlapping with the segregated impurities, thereby maintaining high welding quality and reliability.
3Ease of manufacture
If conventional welding is used, then joining is achieved, but burrs are generated and welding quality is reduced
Solution Approach 1:
The patent replaces conventional welding methods with electron beam welding, which uses a focused electron beam instead of arc-based conventional welding. This substitution eliminates burr generation and produces high-quality welded portions with deep penetration and precise control. The electron beam welding process inherently prevents the formation of surface defects while achieving secure joining.
4Ease of manufacture
If friction press-contact is used, then joining is achieved, but ultrasonic flaw detection is hindered due to burr interference
Solution Approach 1:
The patent replaces friction press-contact with electron beam welding, which does not generate burrs. This substitution eliminates the interference with ultrasonic flaw detection, allowing for accurate and reliable detection of the welded portion quality. The smooth surface produced by electron beam welding enables clear ultrasonic wave propagation without scattering or reflection from burrs.
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 improves the strength and quality of the welded portion by preventing center segregation interference, reducing cycle time, and eliminating burr-related issues, allowing for stable ultrasonic flaw detection and cost reduction in manufacturing.
Implementation Method 1
bringing a joining end surface of the cup member and a joining end surface of the shaft member into abutment against each other and welding the joining end surfaces to form a welded portion having an annular shape
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
A cup member (12a) has a cylindrical portion (12a1), a bottom portion (12a2), and a short shaft portion (12a3) having a solid shaft shape and including a joining end surface (50) at an end portion thereof. A shaft member (13a) has a solid shaft shape and includes a joining end surf ace (51) at one end thereof. The joining end surface (50) of the cup member (12a) and the joining end surface (51) of the shaft member (13a) are brought into abutment against each other and welded through radiation of a high energy intensity beam from a radially outer side to form a welded portion (49) having an annular shape. At this time, center segregation (S) is prevented from interfering with the welded portion (49). The cup member (12a) is formed by forging. The forging includes upsetting a billet having a columnar shape successively in a plurality of stages, extruding the cylindrical portion (12a1) and the short shaft portion (12a3), and ironing the cylindrical portion (12a3). In the course of the upsetting, a region of the billet corresponding to a bottom side of the cup member (12a) is narrowed. With this, an outer joint member of a constant velocity universal joint, which is manufactured by joining a cup member and a shaft member through welding, is improved in strength and quality of a welded portion.