Ring-Shaped Member Manufacturing Yield via Forging and Rolling
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Solution Overview
Problem
Conventional methods for manufacturing ring-shaped members, such as inner and outer rings for rolling bearings, face challenges including high crack risk during cold rolling, increased processing time, and reduced productivity due to the need for multiple cold rolling processes and large diameter expansion rates.
Innovation Solution
A method involving forging to form a joined body from round bar material, cutting and separating it into cylindrical members, and then expanding the inner diameter of these members through rolling to produce ring-shaped members, with specific diameter and weight configurations to minimize scrap and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a large diameter expansion rate is used during cold rolling to produce ring-shaped members, then the inner diameter can be expanded efficiently, but cracks may easily occur in the cylindrical members
Solution Approach 1:
The patent applies preliminary action by performing hot forging to pre-form the cylindrical members with optimized geometry before cold rolling. The hot forging step creates a predetermined shape that reduces the required diameter expansion rate during subsequent cold rolling, thereby preventing cracks while maintaining productivity.
2Productivity
If multiple cylindrical members are cold-rolled to produce lots of ring-shaped members at once, then productivity improves, but the processing time increases significantly
Solution Approach 1:
The patent applies segmentation by dividing the production process into two groups: cylindrical members that require cold rolling and those that do not. By producing some ring-shaped members directly from hot forging without cold rolling, the total number of cold rolling operations is reduced, decreasing processing time while maintaining batch production capacity.
Solution Approach 2:
The patent extracts the cold rolling step from the production process for certain cylindrical members. By identifying and removing the unnecessary cold rolling operations for specific members, the total processing time is reduced while still achieving the required production volume of ring-shaped members.
3Loss of substance
If the same weight configuration is used for large-diameter and small-diameter cylindrical members, then material utilization improves, but the small-diameter member requires excessive diameter expansion during rolling
Solution Approach 1:
The patent applies local quality by assigning different weight configurations to different cylindrical members based on their specific requirements. Instead of using uniform weights, the invention optimizes the weight of each cylindrical member individually, allowing the large-diameter member to have a weight that minimizes expansion requirements during rolling, thereby improving rolling efficiency without increasing material waste.
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 enhances yield and production efficiency by reducing the number of cold rolling processes, minimizing crack risk, and decreasing processing time, while maintaining high product quality.
Implementation Method 1
through upsetting in hot working, a disk-shaped intermediate formed product 202 having an arc-shaped generating line of an outer circumferential surface illustrated in (b) of FIG. 14 is formed from a column-shaped material 201 illustrated in (a) of FIG. 14
Implementation Method 2
through closed die forging, a stepped cylindrically-shaped formed product 203 illustrated in (c) of FIG. 14 is formed from the intermediate formed product 202
Implementation Method 3
a rolling step of expanding an inner diameter size of a part of the plurality of cylindrical members to obtain a ring-shaped member
Data Source
AI summary
There is provided a method for manufacturing ring-shaped members at a good yield and high production efficiency. To achieve this object, the following is performed. A single (a sequence of) forging produces a joined body formed by radially coupling four cylindrical portions with different inner diameter sizes. A cylindrical member that has the largest inner diameter size and a cylindrical member that has the third largest inner diameter size after the forging are employed as ring-shaped members without change. A rolling process is performed on respective cylindrical member that has the smallest inner diameter size and cylindrical member that has the second largest inner diameter size to obtain ring-shaped members. Thus, two sets of ring-shaped members are obtained as two sets of inner rings and outer rings.