Robot Rotation Mechanism With Low-Friction Output Shaft Assembly
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Solution Overview
Problem
Conventional rotation mechanisms face challenges with inefficient assembly and disassembly, low PV limits, and potential seizure issues due to the press-fitting of output shafts, leading to unstable operation and reduced product life.
Innovation Solution
The rotation mechanism features a design with surface roughness Ra of 1.6 µm or less and a static friction coefficient of 0.2 or less on inner peripheral surfaces, using resin carriers and metal output shafts, along with elastic shims and spacers to enhance assembly efficiency and stability, allowing smooth rotation without separate bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the output shaft is press-fitted into the support member, then the assembly structure is simplified, but the assembly work and disassembly work increase and efficiency decreases
Solution Approach 1:
The support member is divided into a rotating member and a non-rotating member, allowing the output shaft to be freely inserted into the rotating member without press-fitting. This segmentation enables easy assembly and disassembly while maintaining structural integrity through the rotational connection.
2Strength
If the output shaft is press-fitted into the support member, then the structural integrity is improved, but the PV limits decrease and seizure may occur
Solution Approach 1:
The connection between the output shaft and rotating member is made dynamic through free rotation capability. The output shaft can rotate freely within the rotating member, allowing relative motion that prevents seizure and reduces frictional heating, thereby maintaining reliability under operational conditions.
Solution Approach 2:
The surface roughness of the inner peripheral surface of the rotating member is controlled at 1.6 µm or less, and the static friction coefficient is reduced to 0.2 or less. These parameter changes minimize friction and sliding resistance, preventing seizure while maintaining structural integrity.
3Manufacturing precision
If the output shaft is press-fitted into the support member, then the positioning accuracy is improved, but the sliding resistance increases and product life decreases
Solution Approach 1:
The surface roughness is precisely controlled at 1.6 µm or less and the static friction coefficient is reduced to 0.2 or less through surface treatment. These parameter changes reduce sliding resistance between the output shaft and rotating member, minimizing wear and extending product life while maintaining positioning accuracy.
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 improves assembly and disassembly efficiency, increases PV limits, and ensures stable operation, extending the product life by reducing sliding resistance and facilitating heat transfer through high thermal conductivity materials.
Implementation Method 1
the static friction coefficient of the inner peripheral surface of the rotating member against the shaft is 0.2 or less
Implementation Method 2
facilitating heat transfer through high thermal conductivity materials
Data Source
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AI summary
A speed reducing mechanism (1B) according to one embodiment of the invention includes an output shaft (9), carriers (13, 14) each of which has an output shaft hole (13b, 14b), and oscillating gears (11, 12) each of which has an output shaft insertion hole (25a, 25b). The output shaft (9) is inserted in the output shaft hole (13b, 14b) and the output shaft insertion hole (25a, 25b) and contacts the inner peripheral surfaces. The surface roughness Ra of the inner peripheral surfaces defining the output shaft hole (13b, 14b) and output shaft insertion hole (25a, 25b) is equal to or less than 1.6 µm. The static friction coefficient of the inner peripheral surfaces against the output shaft (9) is equal to or less than 0.2.