Closed Forging Die Reducing Shaft Sagging
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Solution Overview
Problem
Conventional closed forging dies experience increased processing loads and die damage due to sealed states, leading to 'sagging' in shaft portions, which requires additional material and machining to correct, increasing costs and complexity in producing compact and lightweight constant velocity joints or universal joints.
Innovation Solution
A closed forging die with openable dies and punches that include abutting portions to secure the outer circumference of shaft tips, allowing for preliminary molding with a larger radius of curvature to reduce sagging and eliminate the need for pre-machining the shaft tip, using a preliminary molding process to shape the material before principal molding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a sealed state is established in the closed forging die, then the product can be molded with complete shaft portions, but the processing load drastically increases leading to die damage or short-lived die
Solution Approach 1:
The patent extracts the harmful sealed state by introducing a clearance portion in the shaft molding portion of the die. This clearance creates a controlled gap that prevents complete sealing between the die and punch, allowing material to escape and reducing the processing load while still enabling formation of shaft portions with acceptable precision.
2Duration of action of stationary object
If clearance is provided to shaft molding portions to reduce processing load, then die life is extended, but sagging occurs in shaft portions requiring additional material and machining
Solution Approach 1:
The patent applies preliminary anti-action by designing the clearance portion with specific dimensional relationships (clearance depth less than shaft portion depth, and clearance width controlled within specific ranges) that preemptively counteract the sagging effect. The clearance is positioned and sized to reduce processing load while minimizing material extrusion and sagging, thereby maintaining shaft portion accuracy without requiring post-machining.
3Manufacturing precision
If shaft tip is removed by machining to facilitate post-heat treatment machining, then machining accuracy is improved, but material costs and machining costs increase
Solution Approach 1:
The patent performs preliminary action by forming the shaft tip with the required accuracy directly during the forging process using the optimized clearance portion design. This preliminary shaping eliminates the need for subsequent machining operations to remove the shaft tip, thereby reducing material loss and machining costs while maintaining the necessary machining accuracy for phase matching references.
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
The solution reduces sagging in shaft portions, enabling the production of compact and lightweight joints without pre-machining, lowering material and machining costs, and allowing for more accurate machining references.
Implementation Method 1
the billet 10 plastically deforms, to thereby configure the product 6 including the boss portion 8 and the shaft portions 7
Data Source
AI summary
A closed forging die and a forging method with which sagging can be reduced, a constant velocity joint and a universal joint can be made compact and lightweight, removal of a shaft tip thereof by machining prior to heat treatment is not required, and material costs and machining costs can be reduced by using a closed forging die includes openable dies, and punches that move in an opening/closing direction of the dies to pressurize a material in the dies. By using the die, a product having shaft portions formed radially is manufactured. A clearance is provided to each of the formed shaft portions between a tip surface, and abutting portions are provided to the dies side abutting against at least a tip side of an outer circumferential surface of the shaft portions.