Compact Small Actuator Gear Train for High Torque Feedback
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Solution Overview
Problem
Existing small actuators face challenges in miniaturization, high output, and precision, particularly in attaching to robot joints due to size limitations, real-time force and position measurement difficulties, and torque prediction issues.
Innovation Solution
A small actuator design with a low inertia and high gear ratio, incorporating a coreless DC motor, multiple transmission gears, and sensors to detect rotation angle and torque, enhancing space efficiency and enabling fast torque feedback.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the actuator size is reduced for miniaturization, then the actuator can be attached to robot joints, but the torque generation capability deteriorates
Solution Approach 1:
The patent implements a nested gear train structure where multiple transmission gears (first, second, third, fourth transmission gears) are arranged in sequence, with each gear nested within the spatial envelope of the previous larger gear. This allows achieving high gear ratio (product of individual gear ratios) while maintaining compact overall size, resolving the contradiction between miniaturization and torque generation.
Solution Approach 2:
The patent utilizes three-dimensional spatial arrangement by stacking transmission gears vertically and using offset shafts (first shaft, second shaft, third shaft) at different heights. This vertical dimensionality allows multiple gear stages to coexist in a compact footprint, enabling high torque multiplication without increasing the actuator's horizontal footprint.
2Force
If the gear ratio is increased for high output torque, then the torque generation capability is improved, but the actuator size increases
Solution Approach 1:
The patent implements a nested gear train structure where multiple transmission gears (first, second, third, fourth transmission gears) are arranged in sequence, with each gear nested within the spatial envelope of the previous larger gear. This allows achieving high gear ratio (product of individual gear ratios) while maintaining compact overall size, resolving the contradiction between miniaturization and torque generation.
Solution Approach 2:
The patent combines multiple transmission stages into a single integrated transmission assembly where the first, second, third, and fourth transmission gears work together in sequence. By merging these stages and using integrally formed gear units (first gear unit and second gear unit on first shaft, third gear unit and fourth gear unit on second shaft), the patent achieves high gear ratio without proportionally increasing size.
3Measurement precision
If sensors are added for real-time detection, then the measurement precision is improved, but the device complexity increases
Solution Approach 1:
The patent integrates multiple functions into the transmission structure itself. The transmission gears serve both as mechanical torque multipliers and as reference structures for sensor mounting. The housing integrates motor mounting, gear support, and sensor mounting functions. This multi-functionality reduces overall device complexity despite adding sensing capabilities.
Solution Approach 2:
The patent incorporates sensors (such as encoders or Hall sensors) that detect rotation angle and provide real-time feedback to the control system. This feedback enables precise control of the actuator position and torque, improving measurement precision while the integrated design keeps the added complexity manageable.
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 actuator achieves high precision, low inertia, and improved space efficiency, allowing for precise torque detection and control, with enhanced usability and maintainability.
Implementation Method 1
The motor may be a coreless direct current motor with a low inertia
Implementation Method 2
a first transmission gear including a first gear unit in external contact with the motor gear and a second gear unit formed integrally with the first gear unit; a second transmission gear including a third gear unit in external contact with the second gear unit and a fourth gear unit formed integrally with the third gear unit
Data Source
AI summary
A small actuator is provided. The small actuator includes a housing; a motor disposed in the housing and including a motor gear; a first transmission gear including a first gear unit in external contact with the motor gear and a second gear unit formed integrally with the first gear unit; a second transmission gear including a third gear unit in external contact with the second gear unit and a fourth gear unit formed integrally with the third gear unit; a third transmission gear including a fifth gear unit in external contact with the fourth gear unit and a sixth gear unit formed integrally with the fifth gear unit; a fourth transmission gear including a seventh gear unit in external contact with the sixth gear unit and an eighth gear unit formed integrally with the seventh gear unit; and an output shaft including an output gear in external contact with the eighth gear unit.