Hollow Roller Centering via Single-Setup Lathe Machining
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Solution Overview
Problem
Existing manufacturing processes for hollow rollers in roller bearings, particularly for high-speed applications like aircraft components, often result in imprecise centering of inner and outer radial surfaces, leading to potential unbalance and damage at high rotation speeds.
Innovation Solution
A process involving machining the outer and inner radial cylindrical surfaces on the same lathe, using a first mandrel for initial centering and a second mandrel for precise inner surface machining, followed by separation of the hollow roller preform, ensures precise concentricity and balance, allowing for high hollowness rates without affecting functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If hollow rollers are manufactured by conventional machining processes, then weight reduction is achieved, but centering precision between inner and outer radial surfaces deteriorates
Solution Approach 1:
The patent combines the machining of inner and outer radial surfaces in a single setup on the same lathe, using a first mandrel that supports both surfaces simultaneously. This merging of operations ensures that the inner and outer surfaces are machined with precise mutual centering, eliminating the centering errors that would occur with separate machining operations while maintaining the weight benefits of hollow construction.
Solution Approach 2:
The first mandrel acts as an intermediary device that enables simultaneous support and precise centering of both inner and outer radial surfaces during machining. By using this intermediate fixing mechanism, the patent achieves accurate relative positioning between the hollow inner surface and the outer surface without requiring multiple setup operations, thus resolving the contradiction between weight reduction and manufacturing precision.
2Weight of moving object
If high hollowness rate is used to reduce weight, then lightness is improved, but structural strength deteriorates
Solution Approach 1:
The patent optimizes the hollowness rate parameter to achieve the desired balance between weight reduction and structural strength. By precisely controlling the dimensions of the hollow inner surface relative to the outer surface, and by ensuring accurate centering through the single-setup machining process, the patent maximizes the weight benefit while maintaining sufficient structural integrity for high-speed bearing applications.
3Ease of manufacture
If multiple setup operations are used for machining, then manufacturing flexibility is improved, but manufacturing precision deteriorates
Solution Approach 1:
The patent merges the machining operations for inner and outer radial surfaces into a single setup on the same lathe. The first mandrel is designed to support both surfaces simultaneously, allowing both surfaces to be machined in one continuous operation. This eliminates the need for multiple setup operations and ensures precise coaxiality between the inner and outer surfaces, directly resolving the contradiction between manufacturing flexibility and manufacturing precision.
Data Source
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AI summary
This process for manufacturing a hollow roller of a roller bearing includes at least the following steps: machining an outer radial cylindrical surface (SO), with a circular cross section centered on a first axis (XO), and machining an inner radial cylindrical surface (SI) with a circular cross section centered on a second axis (XI). These two steps are realized on the same lathe (10). The hollow roller (100) is provided with the outer radial cylindrical surface (SO), with a diameter of at least 5 mm, and the inner radial cylindrical surface (SI). An offset between the first axis (XO) and the second axis (XI), measured in the hollow roller (100) between two axial surfaces of the hollow roller, is less than 2 µm, and an inclination angle between the first axis (XO) and the second axis (XI) is less than one minute of angle. The roller bearing (200) comprises amongst others, at least one such roller (100).