Internal Gear Hard Finishing With Even Tool Wear Distribution
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Solution Overview
Problem
The existing methods for hard fine machining of internal gears are limited by topological constraints, which restrict the use of longer grinding worms and result in uneven tool wear, leading to a shorter service life of machining tools.
Innovation Solution
A method using a toothed hard fine machining tool that rotates with varying radial infeed depths and a non-zero axis crossing angle, allowing for rolling machining engagement with increasing tooth thickness to distribute wear evenly and extend tool life, along with specific parameters for infeed depth, tooth thickness ratios, and rotational speeds to optimize machining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If conventional grinding methods are used for internal gears, then machining is possible within space constraints, but tool wear is uneven and service life is short
Solution Approach 1:
The invention applies local quality by creating a tooth thickness gradient along the flank line direction, where tooth thickness increases from the face side toward the rear. This non-uniform tooth thickness distribution ensures that different sections of the tool tooth flank engage the workpiece under optimized conditions, distributing wear more uniformly across the entire tool surface and extending tool service life while maintaining machining precision
Solution Approach 2:
The invention introduces a new dimension to tool design by varying tooth thickness in the flank line direction (along the tooth length), rather than maintaining constant thickness. This dimensional change creates a progressive engagement pattern where the increasing tooth thickness compensates for wear distribution issues, allowing the tool to maintain uniform wear characteristics throughout its service life
2Productivity
If higher relative movement speed is used for material removal, then productivity increases, but risk of grinding burns increases
Solution Approach 1:
The invention employs periodic action through the oscillating feed movement combined with reciprocal tool rotation. The tool performs forward and backward movements with periodic engagement and disengagement from the workpiece, allowing heat to dissipate during disengagement periods while maintaining high productivity during engagement. This periodic cycle prevents continuous heat accumulation that would cause grinding burns
Solution Approach 2:
The invention applies dynamics by implementing an oscillating feed movement with variable velocity rather than constant speed. The feed movement includes acceleration and deceleration phases, creating dynamic engagement conditions that reduce instantaneous heat generation. The reciprocal rotation and oscillating feed work together to create dynamic cutting conditions that maintain high material removal rates while preventing thermal damage to the workpiece
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 enables a more even wear distribution across a larger area, leading to a longer tool service life, efficient removal of material, and improved dynamic rigidity during machining, while maintaining a high removal rate with reduced risk of grinding burns.
Implementation Method 1
material is removed from the gear being machined with an abrasive tooth flank region of the tool toothing
Data Source
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AI summary
The invention relates to a method and a machine tool for hard finishing toothed gearing, particularly internally toothed portions (3), in which method a toothed hard finishing tool (W) which rotates about its axis of rotation is brought into rolling machining engagement with the machined toothed gearing in one pass or in a plurality of passes of differing radial infeed depth under an advance motion with a direction component parallel to the axis of rotation (C) of the machined toothed gearing and under a non-null axis crossing angle, and material is removed from the machined toothed gearing with a tooth flank region (4a) of the machine tool gearing with tooth thickness increasing in the tooth trace direction from the end face (5) facing the machined toothed gearing.