Skiving Tool Geometry and TiAlN Coating for Gear Cutting
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Solution Overview
Problem
Skiving of cylindrical gears faces challenges due to low dynamic stiffness in gear trains and rapid wear of uncoated cutters, limiting its effectiveness compared to shaping and hobbing, until recent advancements in machine tools and coating technologies.
Innovation Solution
A skiving tool with a cutter head featuring equidistant blade slots around its periphery, oriented perpendicular to the axis of rotation, and optionally inclined, with carbide blades coated with TiAlN, allowing for enhanced stability and productivity through optimized cutting geometry and surface speed management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If skiving is used for cutting cylindrical gears, then productivity is improved compared to shaping and broaching, but tool wear increases rapidly and dynamic stiffness requirements are not met
Solution Approach 1:
The patent applies coating technology to change the surface properties of the cutter, transforming it from uncoated to coated with advanced coatings. This parameter change in surface treatment dramatically reduces tool wear and extends tool life, enabling skiving to achieve both high productivity and reliable tool performance
Solution Approach 2:
The patent uses composite material structures by combining the cutter base material with advanced coating layers. This composite approach creates a tool with enhanced surface properties that resist wear while maintaining the structural integrity needed for high-speed cutting operations
2Productivity
If skiving is used for cutting cylindrical gears, then cutting speed is increased, but dynamic stiffness of the gear train becomes insufficient
Solution Approach 1:
The patent replaces traditional mechanical gear train connections with direct drive technology. This substitution eliminates intermediate mechanical linkages that compromise stiffness, providing a direct motor-to-spindle connection that delivers the high dynamic stiffness required for high-speed skiving operations
3Stability of the object's composition
If blade slots are oriented perpendicular to the axis of rotation, then cutting stability is improved, but tool geometry complexity increases
Solution Approach 1:
The patent designs a universal cutter head structure that can accommodate various blade configurations including perpendicular, inclined, and radial orientations. This multi-functional design allows the same basic tool geometry to serve multiple cutting stability requirements without increasing overall complexity
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
The solution significantly improves tool life and productivity, achieving surface finishes comparable to or better than traditional methods, with reduced tool wear and energy consumption, while maintaining high cutting efficiency.
Implementation Method 1
carbide blades coated with TiAlN
Implementation Method 2
reduced tool wear
Implementation Method 3
uses the relative sliding motion between two 'cylindrical gears' whose axes are inclined
Implementation Method 4
the roll motion between the cutting edges and the gear tooth slots occurs with the machine spindle RPM
Implementation Method 5
Due to the continuous chip removal in skiving
Data Source
AI summary
A skiving tool comprising a cutter head (2) having a plurality of cutter blade mounting and positioning slots (8) arranged spaced, preferably equidistant, about the periphery (7) of the cutter head with the blade slots, and hence the cutting blades (4), preferably oriented perpendicular to the axis of rotation (A) of the cutter head. Alternatively, the blade slots may be inclined from the perpendicular orientation by less than 50 degrees, preferably less than 20 degrees, thereby forming a conical shaped cutter. Additionally, the blade slots may be positioned to extend radially from the cutter head axis whereby the longitudinal axis of a cutter blade will intersect the cutter head axis, or the blade slots may be radially offset from the cutter head axis. The blade slots may have any cross-sectional shape such as square, rectangular or those types having generally V-shaped seating surfaces (10) comprising a pair of angled mounting surfaces (12, 14) each less than 90 degrees. In contrast to known cutting blade configurations, the cutting blade (4) of the present invention has its cutting face (16) formed in a surface of the cutting blade that is located opposite to the seating surface or V-shaped seating surfaces (13, 15) of the cutting blade.