Gear Tooth Hard Finishing with Flexible Regrinding Tools
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Solution Overview
Problem
Existing methods for producing toothed or profiled workpieces, such as gears, often result in suboptimal surface quality and strength due to hardening distortions and material removal issues during hard machining, requiring additional costly processes like vibratory finishing or shot peening to achieve desired geometric and surface precision.
Innovation Solution
A process chain involving repeated hard fine machining with a second tool having a significantly lower modulus of elasticity, made of flexible materials like polyurethane or rubber, which allows for precise polishing and grinding without damaging the hardened layer, replacing traditional vibratory finishing and ensuring high surface quality and strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If hard fine machining is performed with a rigid tool after shot peening, then geometric precision can be improved, but the hardened layer is removed and surface quality deteriorates
Solution Approach 1:
The patent changes the material parameter (modulus of elasticity) of the machining tool from rigid to flexible. The flexible tool body has a modulus of elasticity that is at most 33% of the first tool, allowing it to deform elastically during machining. This parameter change enables the tool to accommodate surface irregularities and maintain contact with the hardened layer without removing it, while still achieving the required geometric precision through controlled material removal.
2Manufacturing precision
If additional finishing steps like vibratory finishing are added, then surface quality is improved, but process complexity and costs increase
Solution Approach 1:
The patent merges the hard fine machining and surface finishing operations into a single machining step using the flexible tool. The flexible tool body with embedded abrasives performs both geometric precision machining and surface quality improvement simultaneously, eliminating the need for separate vibratory finishing or burnishing steps. This consolidation reduces process complexity while achieving the desired surface quality.
3Manufacturing precision
If allowance is increased to compensate for alignment errors, then geometric accuracy can be maintained, but material removal increases and hardened layer is eliminated
Solution Approach 1:
The flexible tool body's ability to deform elastically allows it to adapt to minor alignment errors and geometric variations in the workpiece without requiring excessive allowance. The tool conforms to the workpiece geometry through elastic deformation, maintaining accurate cutting contact with minimal material removal. This eliminates the need to increase allowance to compensate for alignment tolerances.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach ensures high surface quality and strength of tooth flanks by compensating for geometric errors and maintaining the hardened layer, reducing process costs and eliminating the need for additional finishing steps like vibratory finishing.
Implementation Method 1
the second tool having a base body which has a second modulus of elasticity, and the second tool has a base body made of plastic or rubber
Implementation Method 2
the gearing or profiling is done with a second tool in the form of a grinding worm, a grinding wheel, a grinding wheel set or a honing wheel
Implementation Method 3
strengthening at least a portion of the workpiece by performing a blasting process
Data Source
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AI summary
The invention relates to a method for manufacturing a workpiece (2) provided with a toothing (1) or profile. To improve the manufacturing process and to produce workpieces with high strength and sufficient accuracy, the invention provides the following sequence of steps: a) soft machining of the workpiece (2), in which the toothing (1) or profile is produced; b) hardening of the produced toothing (1) or profile; c) hard finishing of the toothing (1) or profile, wherein the toothing (1) or profile is machined with a first tool in the form of a grinding worm, a grinding wheel, or a honing wheel, the tool having a base body having a first modulus of elasticity (E1);d) Hardening at least one section of the workpiece (2) by carrying out a shot blasting process; e) following step d): Re-hard finishing of the gear teeth (1) or profile, wherein the gear teeth (1) or profile is machined with a second tool (3) in the form of a grinding worm, a grinding wheel, a grinding wheel set or a honing wheel, wherein the second tool (3) has a base body (4) having a second modulus of elasticity (E2) of at most 33% of the first modulus of elasticity (E1), and wherein the second tool (3) has a base body (4) made of a plastic or of rubber.