CV Joint Butt Welding With Inner Recess for Burr-Free Strength
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Solution Overview
Problem
The existing methods for butt-welding outer joint members of constant velocity universal joints face issues such as burr generation, distorted shapes, increased manufacturing costs due to prolonged cycle times, and poor welding quality due to burrs and hollow cavity formation, which affect the strength and inspection reliability of the welded portions.
Innovation Solution
The method involves forming a recess on the radially inner side of the joining end surface to reduce the abutment area, allowing for efficient heating and reducing the volume of the welded portion, thereby preventing burr formation and improving the welding process through electron beam welding, which ensures deep penetration and stable strength without generating unjoined portions.
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 radially outer side of the joining portion requiring additional turning processing
Solution Approach 1:
The invention utilizes the burrs generated during friction press-contact not as waste to be removed, but as beneficial protrusions on the radially outer side of the joining portion. These burrs serve as reinforcement features that enhance the joint strength and eliminate the need for additional turning processing to remove them.
Solution Approach 2:
Instead of viewing burrs as harmful defects to be eliminated through turning processing, the invention inverts the approach by allowing burrs to remain and even promoting their formation on the radially outer side. This inversion transforms a previously harmful effect into a beneficial feature that strengthens the joint.
2Manufacturing precision
If burrs are removed through turning processing, then the surface quality is improved, but the turning tip is significantly abraded due to high hardness and cracked due to distorted shape
Solution Approach 1:
The invention converts the previously harmful burrs into beneficial features by allowing them to remain on the radially outer side of the joining portion. This eliminates the need for turning processing, thereby preventing tip abrasion and cracking while maintaining surface quality through the beneficial presence of burrs.
Solution Approach 2:
The invention extracts the problematic aspect of burr removal by eliminating the turning processing step entirely. By allowing burrs to remain and serve a beneficial function, the invention removes the need for additional machining operations that cause tip wear and cracking.
3Device complexity
If friction press-contact is used to join cup member and shaft member, then the joining process is simplified, but the cycle time is increased due to multiple passes required for turning
Solution Approach 1:
The invention extracts and eliminates the turning processing step from the manufacturing sequence by allowing burrs to remain as beneficial features. This removal of the turning operation reduces the number of processing passes required and shortens the overall manufacturing cycle time while maintaining joining process simplicity.
4Ease of manufacture
If conventional butt-welding is performed without recess formation, then the welding process is straightforward, but hollow cavity portions are formed causing molten material blowing and degrading welding quality
Solution Approach 1:
The invention applies preliminary action by forming recesses on the radially inner side of the joining end surfaces before welding. This pre-formed recess structure prevents hollow cavity formation during welding, thereby preventing molten material blowing and ensuring high welding quality while maintaining process simplicity.
Solution Approach 2:
The invention applies preliminary anti-action by creating recesses that counteract the formation of harmful hollow cavities during welding. The pre-formed recesses prevent the accumulation of molten material and eliminate the conditions that lead to welding defects, thereby preventing quality degradation before it occurs.
5Area of stationary object
If conventional butt-welding is performed without recess formation, then the abutment area is maximized, but the heating efficiency is reduced and welding penetration is insufficient
Solution Approach 1:
The invention applies local quality by creating recesses at specific locations (radially inner side of joining end surfaces) rather than uniformly modifying the entire surface. This localized modification concentrates heating efficiency in critical areas while maintaining adequate abutment area, enabling deep penetration welding without sacrificing overall contact area.
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 enhances the strength and quality of the welded portion, reduces manufacturing costs, and facilitates reliable ultrasonic flaw detection by eliminating burrs and ensuring complete joint inspection, resulting in improved manufacturing efficiency and product quality.
Implementation Method 1
joining the cup member and the shaft member which are in abutment against each other by welding through use of a high energy intensity beam such as laser welding or electron beam welding
Implementation Method 2
welding through use of a high energy intensity beam such as laser welding or electron beam welding
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
For butt-welding, which includes bringing joining end surfaces (50 and 51) of a cup member (12a) and a shaft member (13a) into abutment against each other and radiating a high energy intensity beam from a radially outer side, the shaft member (13a) has a recess (52 or 53) on a radially inner side of the joining end surface (51) to obtain a welded portion (49) having a closed hollow cavity on a radially inner side after butt-welding. The joining end surface (50) (protruding surface (50a)) of the cup member (12a) protrudes toward a radially inner side with respect to an inner diameter (E) of the joining end surface (51) of the shaft member (13a). With this, a welded portion (74) of an outer joint member (11) of a constant velocity universal joint (10), which is manufactured by joining the cup member (12a) and the shaft member (13a), can be improved in strength and quality.