Inverse Hypocycloid Coupling for Bevel Gear Deburring

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Solution Overview

Problem

The existing methods for deburring bevel gears face challenges such as the formation of primary and secondary burrs, which can lead to safety issues and tool destruction due to uneven cutting forces, and inefficiencies in series production, where deburring tools often lag behind, causing further material removal and increased cutting forces.

Innovation Solution

A method using a CNC bevel gear cutting machine with a deburring tool that employs an inverse hypocycloid coupling ratio between the deburring tool and the bevel gear, allowing for a relative flight movement that removes burrs from the outside to the inside, preventing further material removal after cutting contact and optimizing the deburring process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the deburring tool is guided from the tooth base to the tooth head during primary deburring, then the primary burr is removed, but a secondary burr is created in the functional area of the bevel gear

Engineering Contradiction:
Improveburr removal qualityVSAvoidsecondary burr formation
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent inverts the conventional deburring direction by guiding the deburring tool from the tooth head to the tooth base instead of from the tooth base to the tooth head. This reverse direction prevents the formation of secondary burrs in the functional area while effectively removing primary burrs, as the cutting forces are directed away from the functional tooth surfaces

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

2Ease of manufacture

If the deburring tool cutting edges become blunter, then material is displaced rather than cut, but the tendency to form secondary burr increases

Engineering Contradiction:
Improvedeburring process continuityVSAvoidsurface quality
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent implements feedback control by monitoring the cutting forces during deburring and automatically adjusting the deburring parameters or replacing the tool when bluntness is detected. This ensures that the cutting edges remain sharp enough to cut material rather than displace it, preventing secondary burr formation while maintaining process continuity

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent employs dynamic adjustment of deburring parameters such as feed rate, spindle speed, and tool path based on real-time cutting force measurements. This dynamic control adapts to the changing condition of the cutting edges, maintaining optimal cutting performance throughout the deburring process

Inventive Principle:
Principle #15Dynamics

3Productivity

If the deburring tool is moved into a tooth gap during deburring, then deburring can be performed, but a secondary burr can arise in the functional area of the bevel gear

Engineering Contradiction:
Improvedeburring accessibilityVSAvoidsecondary burr in functional area
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent applies asymmetric tool positioning and cutting direction relative to the tooth gap geometry. The deburring tool is positioned and oriented such that cutting forces are directed away from the functional tooth surfaces while still effectively removing burrs from the tooth edges, preventing secondary burr formation in the functional area

Inventive Principle:
Principle #4Asymmetry

4Productivity

If a fixed positive coupling of the rotary movements is used for continuous deburring, then continuous process is enabled, but the deburring tool may lag and eat further into the material when cutting forces increase

Engineering Contradiction:
Improvecontinuous deburring processVSAvoidmaterial removal control
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent implements feedback control by monitoring the relative position and cutting forces during continuous deburring. When the deburring tool lags or excessive cutting forces are detected, the system automatically adjusts the rotary coupling ratio or feed rate to prevent the tool from eating further into the material, maintaining precision while enabling continuous processing

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3517235B1Method for deburring bevel wheels and CNC machine with a corresponding software for deburring
Publication Date: 2020.12.09 KLINGELNBERG GMBH
  • EP3517235B1 patent drawingFigure 1A~1B
  • EP3517235B1 patent drawingFigure 2
  • EP3517235B1 patent drawingFigure 3~4A

AI summary

A method for deburring bevel gears with a deburring tool comprising at least one cutting edge, comprising the steps of: - rotating the deburring tool about a deburring spindle axis, - rotating a bevel gear (10) about a workpiece spindle axis, wherein - the rotating drive of the deburring tool and the rotating drive of the bevel gear (10) are coupled with an inverse coupling ratio, - it is a continuous deburring method in which the cutting edge performs a relative flight motion with respect to the bevel gear (10), - the relative flight motion is defined by a hypocycloid, and wherein - at least on one tooth edge (11.1, 11.2) of a tooth gap (14) in the region of the bevel gear toe and/or bevel gear heel (Fe) a burr is removed by a cutting edge contact of the cutting edge with the tooth edge (11.1, 11.2).