Herringbone Gear Machining via 5-Axis NC Control
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Solution Overview
Problem
The production of toothed wheels with herringbone gearing on conventional single-purpose machines is expensive, time-consuming, and results in reduced loadability due to the need for central grooves separating helical gearings, which also impairs rolling characteristics.
Innovation Solution
A process using numerically controlled machine tools with at least 4 axes, such as milling machines, to generate control data for guiding milling cutters along machining paths that allow continuous machining of tooth flanks without interruptions, creating smooth transitions and enabling the use of larger tools for faster machining, thereby eliminating central grooves and enhancing loadability and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional single-purpose machines with profile hobs or profile grinding wheels are used to machine herringbone gearing, then the tooth profiles can be machined with accurate geometry, but the machining process becomes time-consuming and requires multiple processing steps with central grooves separating the helical gearings
Solution Approach 1:
The invention divides the herringbone gearing into two separate partial gearings (first and second partial gearing with opposite hand helices) that are machined independently using different tooth flank geometries, allowing continuous machining without central grooves while maintaining geometric accuracy
Solution Approach 2:
The invention transitions from conventional 3-axis machining to 5-axis numerically controlled machining, enabling the milling cutter to approach the workpiece from multiple angles and machine both partial gearings continuously in one setup, eliminating the need for separate processing steps
2Ease of manufacture
If central grooves are introduced to separate the two helical gearings of herringbone gearing, then the machining process becomes feasible on conventional machines, but the loadability and strength of the toothed wheel are reduced
Solution Approach 1:
The invention removes the harmful central groove element from the herringbone gearing design by machining both partial gearings continuously without separation, eliminating the weakness point while maintaining manufacturability through 5-axis NC control
Solution Approach 2:
The invention changes the machining parameters from conventional profile hobbing/grinding to 5-axis end mill machining with specific tooth flank geometries, enabling continuous machining without central grooves and improving both strength and manufacturability
3Manufacturing precision
If profile hobs or profile grinding wheels are used to machine one helical gearing, then the tooth flanks can be formed with correct profile, but the tool cuts into or grinds into the tooth flank of the other helical gearing, making continuous machining impossible
Solution Approach 1:
The invention employs dynamic 5-axis numerically controlled movement of the milling cutter relative to the workpiece, allowing the tool to machine both partial gearings continuously by changing approach angles and positions, preventing interference between opposite helical gearings
Solution Approach 2:
The invention uses a universal 5-axis NC machine tool with an end mill that can machine both left-hand and right-hand helical gearings in one setup, replacing the need for specialized profile hobs or grinding wheels that are limited to single helix directions
Data Source
AI summary
A process and an apparatus for generating control data, wherein a first tooth flank geometry is determined which corresponds to a geometry of a first tooth flank of the herringbone gearing, a second tooth flank geometry is determined which corresponds to a geometry of a second tooth flank of the herringbone gearing, a transition section geometry is determined which corresponds to a geometry of a transition section between the first tooth flank and the second tooth flank, an overall tooth flank geometry is determined which comprises the first tooth flank geometry, the transition section geometry and the second tooth flank geometry, and the control data is generated based on the overall tooth flank geometry and machining paths are indicated, each extending transversely to the profile direction of the tooth flanks and along the first tooth flank geometry, the transition section geometry and the second tooth flank geometry.