Segmented Worm Wheel Side Tooth Design
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Solution Overview
Problem
Worm drives require precise positioning and are prone to premature failure due to side loads, making them impractical for applications with imprecise housings and small motors, which are vulnerable to bearing failure.
Innovation Solution
A side tooth design for worm drives that allows the worm screw to be engaged by the worm wheel on spaced-apart locations on opposite sides, enabling self-alignment and eliminating side loads on the bearings, with a worm wheel design that includes two sets of teeth to distribute the load and reduce the need for precise assembly and larger bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional single-rim worm wheel design is used, then tooth engagement is simple, but precise positioning is required and side loads cause premature failure
Solution Approach 1:
The worm wheel is divided into two separate rims instead of a single rim, with each rim having its own set of teeth. This segmentation allows the worm screw to be engaged at multiple spaced-apart locations, distributing the load and eliminating the need for precise positioning while maintaining reliable tooth engagement.
2Device complexity
If traditional single-rim worm wheel design is used, then structure is simple, but large bearings are required to handle side loads
Solution Approach 1:
By segmenting the worm wheel into two rims with teeth spaced apart, the frictional forces acting on the worm screw from opposite sides create opposing side loads that cancel each other out. This eliminates the net side load that would otherwise be transmitted to the bearings, allowing for smaller bearing sizes.
3Reliability
If two-rim worm wheel design is implemented, then side loads are eliminated and assembly precision is reduced, but device complexity increases
Solution Approach 1:
The worm wheel is segmented into two rims with spaced-apart tooth sets, which distributes the engagement points and eliminates side loads. This segmentation, while adding structural elements, actually simplifies the assembly requirements and can be manufactured as an integrated component, balancing the increased structural complexity with reduced assembly precision requirements.
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 side tooth design enhances the reliability and cost-effectiveness of worm drives by allowing for less precise assembly, reducing the risk of failure, and eliminating the need for large bearings, resulting in a more compact and efficient gear system.
Implementation Method 1
the frictional force between the worm screw and the worm wheel teeth imparts a side load on the worm screw
Data Source
AI summary
A worm drive includes a worm wheel having two spaced-apart outer rims defining an annular channel therebetween for receiving at least a portion of a worm screw. Each of the rims include a set of side teeth in the annular channel extending that are spaced apart from and face the set of teeth of the other rim. The two sets of teeth capture the worm screw and mesh with the screw thread of the worm screw such that the worm screw is engaged by the teeth only on spaced-apart locations on opposite sides of the worm screw. There are no resultant forces in an axial direction of the worm wheel during operation of the worm drive. Also, the worm screw and the worm wheel are self-aligning in the axial direction of the worm wheel.