Bevel Gear Manufacturing with Offset Tapered Milling
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Solution Overview
Problem
Conventional methods for manufacturing bevel gears, such as face milling and face hobbing, are inefficient and less accurate compared to dedicated machines, with 5-axis universal milling offering flexibility but requiring long manufacturing times and lower accuracy.
Innovation Solution
A method using a tapered milling tool positioned offset from the center of a conventional face milling cutter, which follows a circular arc path to duplicate the flank surface forming action of a face mill cutter, allowing for precise bevel gear manufacturing with reduced manufacturing time and comparable accuracy to conventional processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If 5-axis universal milling with pencil shaped end mill is used, then flexibility is improved, but manufacturing time increases 100-1000 times and accuracy decreases
Solution Approach 1:
The patent uses a spherical or cylindrical milling tool that copies the tooth flank surface geometry through enveloping motion. The tool surface is designed to generate the gear tooth flanks by relative rolling motion between tool and workpiece, eliminating the need for complex 5-axis positioning while maintaining geometric accuracy. This copying approach through enveloping paths resolves the contradiction by achieving flexibility with standard tools rather than requiring complex 5-axis universal milling.
2Adaptability or versatility
If 5-axis universal milling with pencil shaped end mill is used, then flexibility is improved, but manufacturing accuracy decreases
Solution Approach 1:
The patent employs a spherical or cylindrical milling tool whose surface geometry copies the desired tooth flank shape through enveloping motion. The tool is positioned and moved along calculated enveloping paths that generate accurate gear tooth flanks. This copying mechanism maintains manufacturing accuracy by using the tool's own geometry as the master form, avoiding the accuracy losses associated with 5-axis universal milling while preserving flexibility.
3Ease of manufacture
If conventional face milling with intermittent indexing is used, then manufacturing process is simple, but manufacturing time increases significantly
Solution Approach 1:
The patent implements continuous indexing where the workpiece rotates continuously during the face hobbing operation, eliminating the intermittent feeding-withdrawing-indexing cycle of conventional face milling. The tool and workpiece rotate in a timed relationship with continuous tool feed to depth, forming all tooth slots in a single plunge. This continuous action maintains process simplicity while dramatically reducing manufacturing time by eliminating repeated positioning and indexing operations.
4Productivity
If conventional face hobbing with continuous indexing is used, then productivity is improved, but manufacturing accuracy decreases compared to dedicated machines
Solution Approach 1:
The patent uses a spherical or cylindrical milling tool with curved surfaces that enable continuous enveloping motion during face hobbing. The spherical/cylindrical tool geometry allows for smooth continuous rotation and feed motion, creating accurate tooth flanks through enveloping paths. This curvature-based approach maintains high accuracy by ensuring continuous contact and enveloping action throughout the cutting process, while preserving the productivity benefits of continuous indexing.
Data Source
AI summary
A method of manufacturing bevel gears with a tool, such as a tapered milling tool (16), wherein the tool is located at a position offset (Rw) from the center position of a conventional face milling cutter and the tool follows a path, such as a circular arc path, during machining.