Double Enveloping Worm Shaft Machining for Uniform Tooth Alignment
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Solution Overview
Problem
Existing methods for machining double enveloping worm shafts result in non-uniform tooth surface contact with the worm wheel due to variations in curvature, leading to reduced machining precision and increased need for post-machining processes.
Innovation Solution
An apparatus comprising a bed, rotation unit, alignment unit, and angle changing unit that allows the workpiece to rotate while the cutter remains fixed, ensuring teeth are cut to a uniform depth aligned with the worm wheel's center, using a concentric circle structure and adjustable angle to match the curvature of the worm wheel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a rotating cutter is used to machine the double enveloping worm shaft, then the threaded part can be formed on the workpiece, but the tooth shape orientation is not directed toward the center of the worm wheel resulting in non-uniform contact surface
Solution Approach 1:
Instead of rotating the cutter to machine the worm shaft, the invention inverts the approach by keeping the cutter stationary and rotating the workpiece on a horizontal axis. This inversion allows the cutting edges to engage the workpiece in a way that naturally directs the tooth shape orientation toward the center of the worm wheel, achieving uniform contact surface without requiring post-machining adjustments
2Device complexity
If the cutter rotates in a circular arc with fixed rotational radius, then the machining process can be simplified, but the tooth shape orientation does not align with the center of the worm wheel due to curvature differences
Solution Approach 1:
The invention applies dynamics by making the rotational axis of the workpiece adjustable. The horizontal rotational axis can be positioned at different heights and angles to match the specific curvature requirements of different worm wheel sizes. This dynamic adjustment capability allows the same machining apparatus to precisely machine worm shafts for various worm wheel curvatures while maintaining tooth shape alignment with the worm wheel center
3Ease of manufacture
If a fixed rotational radius is used for the cutter, then the machining setup is simplified, but additional post-machining is required to achieve uniform contact surface
Solution Approach 1:
The invention implements preliminary action by configuring the machining parameters and rotational axis position before the actual cutting operation begins. By pre-setting the horizontal rotational axis at the appropriate height and angle that corresponds to the worm wheel's curvature, the tooth shapes are machined with correct orientation from the start, eliminating the need for subsequent post-machining operations to achieve uniform contact surface
Data Source
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AI summary
The present disclosure relates to an apparatus for machining a double enveloping worm shaft, and more particularly, to an apparatus for machining a double enveloping worm shaft, which cuts threads on a workpiece having a double enveloping body having a central portion formed therein in a concave arc-shaped outer circumferential surface and in which teeth of the machined double enveloping worm shaft are cut to a uniform depth while being always directed toward a central axis of a worm wheel, machining precision of the double enveloping worm shaft is increased, and thus post-machining is not required. An apparatus for machining a double enveloping worm shaft according to the present disclosure includes a bed including a main shaft for rotating a workpiece having a double enveloping body and a tailstock for fixing the workpiece to the main shaft, a rotation unit provided with a rotation plate which rotates in a left-right direction and on which the bed is mounted, an alignment unit that moves the bed in a front-rear direction and the left-right direction so that a circular arc cutting surface of the double enveloping body is disposed in a concentric circle structure with a rotational path of the rotation plate in reference to a central point of the rotation plate, and a cutter fixed to a central side of the rotation plate to face the circular arc cutting surface of the double enveloping body, wherein, while the workpiece revolves at an outer edge of the cutter, a thread of the double enveloping worm shaft is machined in the circular arc cutting surface of the double enveloping body.