Robot Speed Reducer Shaft Interface for Low-Friction Assembly
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Solution Overview
Problem
Conventional speed reducing mechanisms in cooperative robots face challenges with assembly and disassembly efficiency, stability, and product life due to high friction and low PV limits, leading to potential seizure issues.
Innovation Solution
A rotation mechanism with a shaft and rotating member configuration that reduces static friction coefficient and surface roughness, allowing for improved assembly and disassembly efficiency, increased PV limits, and stable operation, featuring a metal shaft and resin rotating member with specific surface finishes and thermal conductivity enhancements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the output shaft is press-fitted into the support member, then the assembly strength is improved, but the assembly work and disassembly work increase
Solution Approach 1:
The invention extracts the output shaft from the press-fitted connection with the support member, allowing it to rotate freely within a shaft insertion hole. This eliminates the need for press-fitting operations during assembly and disassembly, significantly reducing manufacturing time and labor while maintaining sufficient connection strength through the shaft bearing structure.
2Stability of the object's composition
If the output shaft is press-fitted into the support member, then the connection stability is improved, but the PV limits decrease and seizure may occur
Solution Approach 1:
The invention introduces a shaft bearing as an intermediary component between the output shaft and the support member. This bearing mediates the interaction by providing a low-friction interface that reduces PV values and prevents seizure, while still maintaining stable connection through the shaft insertion hole configuration.
Solution Approach 2:
The invention changes the friction parameter by allowing the output shaft to rotate freely within the shaft insertion hole rather than being press-fitted. This parameter change from high friction (press-fit) to low friction (free rotation with bearing) increases the PV limits and prevents seizure while maintaining connection stability.
3Loss of energy
If the surface roughness is reduced to 1.6 μm or less, then the sliding resistance decreases and PV limit increases, but the manufacturing precision requirements increase
Solution Approach 1:
The invention changes the surface roughness parameter to 1.6 μm or less on the inner peripheral surface of the shaft insertion hole. This parameter change reduces sliding resistance and increases PV limits, preventing seizure while maintaining a achievable manufacturing precision level that balances performance and manufacturability.
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 solution enhances assembly and disassembly efficiency, increases the product life of the speed reducing mechanism by reducing sliding resistance and increasing the PV limit, ensuring stable operation and extended lifespan.
Implementation Method 1
the static friction coefficient of the inner peripheral surface against the shaft is equal to or less than 0.2
Data Source
AI summary
A speed reducing mechanism according to one embodiment includes an output shaft, carriers each of which has an output shaft hole, and oscillating gears each of which has an output shaft insertion hole. The output shaft is inserted in the output shaft hole and the output shaft insertion hole and contacts the inner peripheral surfaces. The surface roughness Ra of the inner peripheral surfaces defining the output shaft hole and output shaft insertion hole is equal to or less than 1.6 μm. The static friction coefficient of the inner peripheral surfaces against the output shaft is equal to or less than 0.2.