Machine Tool Spindle Synchronization for Gear Geometry Accuracy

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Solution Overview

Problem

Existing machine tools for machining geared work pieces often result in deviations from the desired geometry due to inaccuracies in translational movements and unstable coupling, leading to imprecise tooth structures and gear formations.

Innovation Solution

A machine tool design featuring a milling spindle unit with rotational and translational movements, stable coupling to a machine tray, and adjustable machining elements with helical arrangements, allowing precise control and compensation for inaccuracies through synchronized rotational and translational movements, enabling the formation of precise tooth structures and gear geometries.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If indexing methods are used to machine geared work pieces, then the machining process is simple, but deviations from the desired geometry occur due to tool shape limitations

Engineering Contradiction:
Improvemachining process simplicityVSAvoidwork piece geometry accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent replaces the traditional indexing method (which relies on the mirror image of the tool shape) with a generating method where the tooth profile is created through the coordinated motion of the tool and workpiece. The control system synchronizes the rotational speed of the workpiece spindle with the rotational and translational movements of the tool spindle, allowing precise generation of tooth geometry rather than relying on fixed tool shapes.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If generating methods are used with multiple machining tools and turrets, then different work piece geometries can be obtained, but translational movements cause inaccuracies and unstable coupling

Engineering Contradiction:
Improvework piece geometry varietyVSAvoidtooth structure accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent extracts and eliminates the problematic translational movement component from the machining system. Instead of moving the toolpiece translationally along the workpiece, the system uses only rotational movements of both the workpiece spindle and tool spindle, with the toolpath generated through coordinated rotation. This removes the source of translational inaccuracies while maintaining the ability to machine different geometries through varying rotational parameters.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent implements a control system that synchronizes the rotational speed of the workpiece spindle with the rotational and translational movements of the tool spindle. This feedback mechanism ensures that the generating motion maintains precise geometric relationships throughout the machining process, compensating for any deviations and ensuring accurate tooth profile generation.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If the work piece is subjected to translational movement during machining, then different sections can be accessed, but inaccuracy is introduced affecting final geometry

Engineering Contradiction:
Improvework piece accessibilityVSAvoidfinal geometry accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent substitutes the translational movement mechanism with a pure rotational movement system. The tool accesses different sections of the workpiece through coordinated rotational movements of both spindles, eliminating the need for translational displacement of the workpiece. This substitution removes the source of translational inaccuracy while maintaining full accessibility to different workpiece sections through rotational positioning.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Data Source

PatentEP2173511B1Machine tool
Publication Date: 2014.05.28 SCHUSTER MASCHINENBAU GMBH
  • EP2173511B1 patent drawingFigure 1
  • EP2173511B1 patent drawingFigure 2
  • EP2173511B1 patent drawingFigure 3~4

AI summary

The invention relates to a machine tool for machining a work piece having a main spindle unit with a preferably vertical spindle axis, and a machining spindle unit, particularly a hobbing spindle unit that is arranged next to the spindle axis in a direction crosswise to the spindle axis to accommodate a machining tool, with said machining spindle unit being displaceable along a first guiding direction, in particular vertically (z) by means of a first guide and crosswise, preferably perpendicularly (x) or approximately perpendicularly displaceable to the first guiding direction, particularly the vertical, by means of a second guide, can advance to a work piece clamped in the main spindle unit, and can swivel around a swivel axis (B), preferably perpendicularly to the spindle axis (A) of the machining spindle unit, and with the machining tool having an arbitrary number of helically arranged machining elements, in particular a single- or multi threaded generating means, adapted to execute generating teeth manufacturing methods.