Double Helical Gear Skiving Without a Circumferential Groove
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Solution Overview
Problem
The challenge in machining gears with real herringbone gearing is the limited space for machining tools due to the alignment of teeth in opposite directions, leading to the need for a circumferential groove that widens the gear, and existing methods struggle to minimize this widening effectively.
Innovation Solution
The method involves producing a double helical gear wheel with gear halves offset by an angular amount relative to the axis of rotation, using a skiving process that combines hobbing and shaping with continuous rolling and axial feed, allowing the skiving tool to move into the tooth gap without colliding with adjacent teeth, thus minimizing the required space and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a circumferential groove is formed between the tooth halves to accommodate the machining tool, then the tool can access the apex point of the teeth, but the gear width increases due to the groove
Solution Approach 1:
The patent introduces an angular offset between the two tooth halves of the double helical gear, creating clearance in the angular dimension rather than requiring additional width. This angular displacement allows the machining tool to access the apex point without needing a circumferential groove that would increase gear width, thus resolving the contradiction by solving the accessibility problem through a different dimensional approach.
2Device complexity
If the gear halves are offset by axial distance only, then the structure is simple, but there is insufficient space for the machining tool to reach the apex point
Solution Approach 1:
The patent adds an angular offset component to the traditional axial offset arrangement of gear halves. This angular displacement creates the necessary clearance for tool access to the apex point while maintaining relative structural simplicity. The angular offset works in conjunction with the axial offset to provide the required machining space without significantly complicating the gear structure.
3Ease of manufacture
If milling is used to machine the teeth with angular offset, then tool access is improved, but the machining time and complexity increase compared to simpler methods
Solution Approach 1:
The patent changes the machining method from conventional milling to skiving, which is a continuous rolling cutting process. This parameter change in the machining method, combined with the angular offset of the gear halves, enables efficient machining of the tooth flanks and apex points without the time-consuming operations associated with traditional milling, thus reducing overall machining time while maintaining good tool access.
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 the production of gears with minimized width and increased axis crossing angle, allowing for efficient processing of double helical gearing without the need for a circumferential groove, reducing the processing time and maintaining the gear's geometry.
Implementation Method 1
gear skiving using a gear skiving wheel which, during the gear skiving process, extends from the teeth of one of the half of the toothing to the respective adjacent tooth gaps of the other half of the toothing
Implementation Method 2
This relative motion is used as a cutting motion, the main cutting direction of which is aligned along the tooth gap of the workpiece
Data Source
Figure 1
Figure 2
AI summary
The invention provides a method for manufacturing gears, with which gears with double helical teeth can be produced particularly economically. For this purpose, in the inventive method for machining a gear (1) which is provided with a double helical toothing in which the teeth (4) of one tooth half (2) are formed in a direction opposite to the teeth (5) of the other tooth half (3), wherein the tooth halves (2,3) are arranged offset from each other by an angular amount (β) with respect to the axis of rotation (D1) of the gear (1), a gear blank is provided on which the teeth (4,5) provided on the gear (1) are produced by gear skiving using a gear skiving wheel (13) which, during the gear skiving process, extends from the teeth (4,5) of one of the tooth halves (2,3) into the respective adjacent tooth gaps (9,10) of the other tooth half (3,2).