Cylindrical Ring Chamfering via Preliminary Cold Forging
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Solution Overview
Problem
Conventional methods for manufacturing cylindrical ring members, such as radial ball bearing components, face challenges in achieving accurate shape formation and preventing burr formation during chamfering, leading to increased processing costs and reduced shape accuracy.
Innovation Solution
The method involves forming a preliminary chamfer portion with a larger radius of curvature than the normal chamfer portion, allowing the holding surface to initially contact a radial intermediate portion of the cylindrical portion, rather than the chamfering surface, to facilitate smooth metal flow and prevent burr formation, while also performing other processing steps simultaneously.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the holding surface contacts the chamfering surface directly during cold forging, then the chamfer portion can be formed, but burr formation occurs and shape accuracy deteriorates
Solution Approach 1:
A preliminary chamfer portion with larger radius of curvature is formed on the cylindrical portion before the final chamfering process. This preliminary chamfer modifies the metal flow pattern, preventing direct contact between the holding surface and chamfering surface during cold forging, thereby eliminating burr formation and improving shape accuracy of the final chamfer portion
Solution Approach 2:
The invention applies different radius of curvature values to different stages of chamfer formation: the preliminary chamfer portion has a larger radius of curvature to facilitate smooth metal flow, while the final normal chamfer portion has a smaller radius of curvature to achieve the required precise shape. This local differentiation of geometric properties resolves the contradiction between burr prevention and shape accuracy
2Productivity
If conventional cold forging is used to form chamfer portions, then processing can be completed in one step, but shape accuracy of the chamfer portion deteriorates due to burr formation
Solution Approach 1:
The preliminary chamfer portion is formed as a preparatory step before the final cold forging chamfering process. This preliminary action modifies the workpiece geometry to enable subsequent high-precision chamfering without burr formation, thereby maintaining both high productivity and manufacturing precision through an optimized two-stage process
3Manufacturing precision
If the radius of curvature of the chamfer portion is made small to achieve precise shape, then shape accuracy improves, but burr formation occurs during cold forging
Solution Approach 1:
The preliminary chamfer portion with larger radius of curvature is formed first to establish favorable metal flow conditions. This preliminary geometry enables the subsequent formation of the final chamfer with small radius of curvature without causing burr formation, as the preliminary chamfer has already prepared the material flow pattern
Solution Approach 2:
Different radius of curvature values are applied at different stages: the preliminary chamfer uses a larger radius to prevent burr formation during forming, while the final chamfer uses a smaller radius to achieve precise shape accuracy. This local differentiation resolves the contradiction between small radius (for precision) and burr formation
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 shape accuracy of the chamfer portion and prevents burr formation, thereby reducing manufacturing costs and improving the overall processing efficiency.
Implementation Method 1
forming an intermediate material (including an intermediate material consisting of a cylindrical portion) by subjecting a metal columnar material to plastic processing
Implementation Method 2
chamfering step by cold forging
Implementation Method 3
allowing the holding surface to initially contact a radial intermediate portion of the cylindrical portion, rather than the chamfering surface, to facilitate smooth metal flow
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3
AI summary
A method for manufacturing a cylindrical ring member includes a step for forming a metal intermediate material having a cylindrical part, and a chamfering processing step for cold forging, which is a step for forming regularly chamfered parts (61 - 62) on the peripheral edges of ends of the cylindrical part in the axial direction by pressing an end part in the radial direction of an end surface in the axial direction of the cylindrical part onto a ring shaped chamfered processing surface (55, 60) provided on a mold constituting a molding device. A chamfering process is carried out by cold forging in a state where preliminary chamfered parts (36 - 37) for which the width dimension thereof is larger than the width dimension in the radial direction of the regularly chamfered parts are formed on the peripheral edges of ends of the cylindrical part in the axial direction.