Hardened Gear Wheel Machining with Skiving and Honing in One Clamping
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Solution Overview
Problem
The existing manufacturing process for hardened toothed work wheels is inefficient due to clamping errors and hardening distortions, which lead to uneven oversize distribution and require multiple machining steps, including grinding and honing, where the honing wheel needs to 'feel' its way into the tooth gaps, resulting in inaccuracies and suboptimal surface quality.
Innovation Solution
A method where a pre-toothed, hardened work wheel is clamped and most of the oversize is removed by skiving, followed by honing without re-clamping, using a combination tool with a skiving wheel and a CBN honing wheel, where the honing wheel is dressed in the same machine tool, eliminating errors and achieving high accuracy and surface quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple machining steps (grinding, honing) are used to finish hardened gears, then surface quality and accuracy can be improved, but clamping errors and hardening distortions cause uneven oversize distribution requiring repeated probing and repositioning, increasing manufacturing complexity and time
Solution Approach 1:
The patent combines roughing (skiving) and finishing (honing) operations into a single machining setup. The workpiece remains clamped on the workpiece spindle throughout both operations, eliminating the need for repositioning between different machine tools. This merging of operations resolves the contradiction by maintaining high precision while reducing manufacturing complexity.
Solution Approach 2:
The patent performs skiving (roughing) as a preliminary action before honing (finishing). By removing the majority of the oversize through skiving first, the subsequent honing operation only needs to remove small amounts of material to achieve final precision. This preliminary action compensates for hardening distortions and clamping errors before the precision finishing step.
2Manufacturing precision
If the honing wheel is probed into tooth gaps of a repositioned gear, then finishing can be performed, but clamping errors and runout errors lead to air cuts and reduced machining accuracy
Solution Approach 1:
The patent merges the roughing and finishing operations into a single continuous process without repositioning the workpiece. The workpiece remains clamped on the workpiece spindle throughout, eliminating runout errors and clamping inconsistencies that would otherwise cause air cuts and reduce reliability.
Solution Approach 2:
The patent maintains continuous machining action by performing skiving and honing in sequence without interrupting the clamping state. The workpiece remains securely held on the workpiece spindle throughout both operations, ensuring consistent positioning and eliminating air cuts caused by repositioning errors.
3Productivity
If gear skiving is used to remove stock allowance, then hardening errors and clamping errors can be compensated, but the tooth flanks require subsequent honing to achieve sufficient surface finish and accuracy
Solution Approach 1:
The patent segments the machining process into two distinct operations: skiving for roughing (high productivity) and honing for finishing (high precision). Each operation is optimized for its specific function, with skiving removing the majority of material efficiently and honing achieving the required surface finish and accuracy.
Solution Approach 2:
The patent maintains continuous useful action by performing both skiving and honing in the same machining setup without repositioning. The workpiece remains clamped on the workpiece spindle throughout, allowing seamless transition from roughing to finishing while maintaining positioning accuracy and eliminating setup errors.
4Ease of manufacture
If the honing wheel is dressed externally, then tool preparation can be done separately, but runout and clamping errors in the dressing process negatively affect honing accuracy
Solution Approach 1:
The patent implements self-service by dressing the honing wheel internally within the same machining setup where it will be used. The dressing operation is performed in-situ, eliminating the need for separate external tool preparation that would introduce runout and clamping errors. The system dresses its own tooling to ensure maximum accuracy.
Solution Approach 2:
The patent merges the dressing operation with the honing operation by performing both in the same machining setup. The honing wheel is dressed internally within the device, combining tool preparation and tool usage into a single integrated process, thereby eliminating errors from separate dressing operations.
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 method significantly reduces errors and achieves maximum accuracy and surface quality by removing the majority of the oversize through skiving and finishing with honing in the same clamping, eliminating the need for multiple re-clamping and improving the machining efficiency and precision.
Implementation Method 1
the substantial portion of the stock allowance is removed by gear skiving with a skiving wheel driven by a tool spindle
Implementation Method 2
the tooth flanks are finely machined using a honing wheel
Implementation Method 3
using a CBN honing wheel, where the honing wheel is dressed in the same machine tool
Data Source
Figure 1~3
AI summary
The invention relates to a method for machining toothed and hardened work wheels (1), comprising the following steps: mounting a work wheel (1) that is hardened and pre-toothed with an allowance onto a work piece spindle (4); removing at least 50% of the allowance by means of gear skiving with a skiving wheel (5) that is rotatably driven by a tool spindle (7); precision-machining the work wheel (1) in unchanged tension by means of a honing wheel (6). The forward movement (Vs) occurs during gear skiving in the extension direction of the toothing (2). The delivery (VH) of the work piece (1) that is moved in an oscillating manner in the extension direction of the toothing (2) occurs during honing in the radial direction. The skiving wheel (5) and the honing wheel (6) are driven by a common tool spindle (7). The invention also relates to a device for carrying out the method.