Spiral Gear Groove Whirling to Reduce End Machining Interference
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Solution Overview
Problem
Existing gear manufacturing methods, such as whirling machining, result in incomplete machined portions at the ends of the workpiece due to interference between the whirling cutter and the chuck or center, especially as the lead angle increases, leading to longer incomplete machined portions and waste of the workpiece.
Innovation Solution
A manufacturing method that involves rotating a rod-shaped workpiece and a tool with a cutting edge around twisted axes, allowing synchronized relative movement to form a spiral tooth groove while maintaining rolling contact with a target contour line, with the diameter of the rolling circle being between 1 to 1.5 times the tooth tip circle diameter, reducing the axis inclination angle and preventing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If whirling machining is used to form spiral grooves on the workpiece, then gear manufacturing is achieved, but incomplete machined portions are generated at both end portions of the workpiece
Solution Approach 1:
The patent changes the inclination angle parameter of the whirling cutter axis relative to the workpiece axis. By optimizing this angle, the cutter can reach closer to the end portions of the workpiece while maintaining proper cutting geometry, thereby reducing incomplete machined portions without compromising gear manufacturing capability
Solution Approach 2:
The patent introduces axial movement of the whirling cutter in addition to the traditional rotational whirling motion. This adds a dimensional component to the cutting path, allowing the cutter to effectively engage with and machine the end portions of the workpiece that were previously inaccessible
2Shape
If the lead angle of the groove is increased, then the gear lead angle is improved, but the length of incomplete machined portion increases
Solution Approach 1:
The patent simultaneously optimizes multiple parameters including the whirling cutter inclination angle and the axial movement distance. By coordinating these parameter changes, high lead angles can be achieved while the axial movement ensures the cutter reaches the end portions, preventing incomplete machining even at high lead angles
3Area of stationary object
If the whirling cutter is brought close to the chuck or center, then machining coverage is improved, but interference between the cutter and chuck or center occurs
Solution Approach 1:
The patent utilizes axial movement of the whirling cutter as an additional degree of freedom. This allows the cutter to approach the end portions of the workpiece along the axial direction without requiring excessive lateral proximity to the chuck, thereby expanding machining coverage while avoiding interference
4Shape
If the inclination angle of the whirling cutter axis is increased, then the lead angle capability is improved, but the interference with chuck increases
Solution Approach 1:
The patent optimizes the inclination angle parameter within a specific range and combines it with controlled axial movement. This parameter optimization allows high lead angle capability while the axial movement component ensures the cutter path does not intersect with the chuck, preventing interference
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 reduces the length of incomplete machined portions and maintains gear accuracy by minimizing interference, thereby improving the manufacturing efficiency and reducing waste.
Implementation Method 1
bringing the cutting edge of the tool into contact with the outer peripheral surface of the workpiece and removing a material of the workpiece at a contact position by the relative movement between the tool and the workpiece
Data Source
Figure 1A~1B
Figure 2A
Figure 2B
AI summary
A manufacturing method of a gear (30) includes: rotating a rod-shaped workpiece around a first axis (A1); rotating a tool having a cutting edge (201) on an outer peripheral side around a second axis at a twisted position with respect to the first axis; and while relatively moving the workpiece and the tool in a direction parallel to the first axis at a speed synchronized with a rotation speed of the workpiece, forming a spiral tooth groove (301) on an outer peripheral surface of the workpiece by bringing the cutting edge of the tool into contact with the outer peripheral surface of the workpiece and removing a material of the workpiece at a contact position by the relative movement between the tool and the workpiece. In a plane perpendicular to the first axis, the workpiece is rotated around the first axis and the workpiece and the tool are relatively moved in the direction parallel to the first axis at the speed synchronized with the rotation speed of the workpiece such that a contour line (OE) of the cutting edge of the tool is in rolling contact with a target contour line (OG), which is a contour line of the spiral tooth groove to be formed, at a predetermined point (R) of the target contour line or an extension line of the target contour line without slipping, and rotates while sliding with respect to the target contour line or the extension line at a point other than the predetermined point. In the plane perpendicular to the first axis, a diameter (DF) of a first circle, which is a circle centered on the first axis and passing through the predetermined point, is 1 time or more and 1.5 times or less a diameter (DT) of a second circle which is a tooth tip circle (CT) of the gear manufactured from the workpiece centered on the first axis.