Precession Gear Cam Unit With Lightweight-Steel Split Structure
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Solution Overview
Problem
The existing precession speed-reducing apparatus faces challenges with increased inertia and reduced controllability due to the use of steel for the cam unit, especially when the diameter is large, which affects durability and efficiency.
Innovation Solution
A speed-reducing or -increasing apparatus is designed with a cam unit comprising a lightweight first member and a steel second member, where the first member has a lower specific gravity than the second member, allowing for reduced inertia while maintaining durability through the use of steel for the rolling element portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cam unit is made of steel to increase durability, then the durability is improved, but the inertia of the cam unit is increased and controllability is reduced
Solution Approach 1:
The cam unit is divided into two separate members: a first member made of lightweight material and a second member made of steel. The steel second member contains the rolling element rolling portion to ensure durability at the contact point, while the lightweight first member reduces overall inertia. This segmentation allows each part to be optimized for its specific function.
Solution Approach 2:
The steel material is applied locally only to the second member where the rolling element rolling portion is formed, rather than making the entire cam unit steel. This localized application of high-density material ensures durability where needed (at the rolling contact point) while keeping the rest of the cam unit lightweight for reduced inertia.
2Strength
If the diameter of the cam unit is increased, then the rolling element rolling portion can accommodate larger rolling elements for better load capacity, but the inertia is significantly increased
Solution Approach 1:
The cam unit uses a composite structure combining lightweight material and steel material in a single component. This allows the cam unit to achieve both low inertia (from the lightweight material) and high load capacity (from the steel rolling element rolling portion), resolving the contradiction between size/strength and weight.
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 design reduces the inertia of the cam unit, enhances controllability, and maintains durability by using a lightweight material for the first member and steel for the rolling element, improving the overall performance of the precession speed-reducing apparatus.
Implementation Method 1
a rolling element rolling portion where the rolling element rolls is formed on the cam unit
Data Source
AI summary
A speed-reducing or -increasing apparatus, with first and second crown gears facing one another, with a cam unit that causes the first crown gear to incline with respect to the second crown gear so that the first crown gear meshes with the second crown gear, that causes the first crown gear to precess in such a manner as to move the meshing position, and couples to an input or output shaft. A rolling element is between the cam unit and the first crown gear, and the cam unit includes a first member that couples to the input or output shaft and a second member made of steel and including a rolling element rolling portion where the rolling element rolls, the second member configured to be incapable of rotating relatively to the first member, and at least part of the first member having a lower specific gravity than the second member.