Threaded Grinding Wheel Dressing via Virtual Gear Meshing

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Solution Overview

Problem

Dressing gears for internal gear grinding are difficult to manufacture with high accuracy due to their complex edge profiles, which affects the precision of the grinding process.

Innovation Solution

Using an externally-toothed dressing gear that can mesh with a virtually designed external gear, allowing the threaded grinding wheel to be dressed accurately by simulating the meshing state with a virtual external gear, enabling precise alignment and dressing of the grinding wheel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a dressing gear with the same specifications as the internal gear is used, then the dressing gear can be manufactured to match the gear specifications, but the edge profile becomes complicated and manufacturing accuracy deteriorates

Engineering Contradiction:
Improvedressing gear manufacturing accuracyVSAvoiddressing gear edge profile complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies the copying principle by creating a virtual external gear that replicates the meshing characteristics of the internal gear system. Instead of directly copying the complex internal gear geometry into a physical dressing gear, the invention copies the functional meshing behavior through a virtual model, which then guides the design of a simpler externally-toothed dressing gear. This allows the dressing gear to reproduce the necessary dressing action without inheriting the manufacturing difficulties of internal gear profiles.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent applies inversion by transitioning from an internally-toothed dressing gear (which would match the internal gear specifications) to an externally-toothed dressing gear. By inverting the gear type from internal to external, the solution transforms the manufacturing problem into a more solvable form while maintaining the essential meshing function needed for accurate dressing of the threaded grinding wheel.

Inventive Principle:
Principle #13The other way round (Inversion)

2Manufacturing precision

If a threaded grinding wheel for internal gear grinding is dressed with high accuracy, then the gear finishing precision is improved, but the dressing gear manufacturing becomes more difficult

Engineering Contradiction:
Improvegear finishing precisionVSAvoiddressing gear manufacturability
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent introduces a virtual external gear as an intermediary between the internal gear specifications and the physical dressing gear design. This virtual model serves as a mediator that translates the requirements for high-precision internal gear grinding into design parameters for a manufacturable externally-toothed dressing gear, thereby decoupling the precision requirement from the manufacturing difficulty.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention copies the functional meshing characteristics of the internal gear system into a virtual external gear model, which then serves as the basis for designing the physical dressing gear. This copying approach allows the essential dressing function to be replicated without directly manufacturing a complex internal gear profile, thus improving ease of manufacture while maintaining gear finishing precision.

Inventive Principle:
Principle #26Copying

3Manufacturing precision

If the dressing gear has complicated edge profiles to match internal gear specifications, then the gear specifications can be accurately reproduced, but the dressing process becomes more complex and time-consuming

Engineering Contradiction:
Improvegear specification accuracyVSAvoiddressing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent copies the meshing functionality of the internal gear into a virtual external gear model, which then guides the design of a simpler externally-toothed dressing gear. This copying process preserves the essential gear specification accuracy while eliminating the need for complicated physical internal gear profiles in the dressing gear, thereby simplifying the overall dressing process.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

By inverting the gear type from internal to external, the patent simplifies the dressing gear geometry while maintaining the ability to accurately reproduce gear specifications. The externally-toothed configuration is inherently simpler to manufacture and operate than an internally-toothed gear, thus reducing dressing process complexity while preserving precision.

Inventive Principle:
Principle #13The other way round (Inversion)

Data Source

PatentEP2556923B1Method for dressing a threaded grinding wheel for internal gear grinding
Publication Date: 2021.09.22 MITSUBISHI HEAVY IND MACHINE TOOL CO LTD
  • EP2556923B1 patent drawingFigure 1
  • EP2556923B1 patent drawingFigure 2
  • EP2556923B1 patent drawingFigure 3

AI summary

Disclosed is a method for dressing a threaded grinding stone for internal gear grinding, by which a threaded grinding stone for grinding an internal gear can be dressed with a high degree of accuracy by using a dressing gear that has been produced with a high degree of accuracy. In a state in which a barrel-shaped threaded grinding stone (11), which is disposed at an axial angle (∑) to the internal gear (W) that is conferred during the grinding of said internal gear (W), and an external tooth-type dressing gear (13), which is capable of meshing with a virtual external gear (14) virtually formed in a manner so as to mesh with the internal gear (W) in place of the threaded grinding stone (11) disposed at the axial angle (∑), have been meshed together, the threaded grinding stone (11) and the dressing gear (13) are simultaneously rotated while being moved relatively in a circular arc in the X-Y plane, whereby the dressing gear (13) dresses along the entire area in the axis direction of the threaded grinding stone (11).