Elastic Gear Module for Compact Series Actuator Torque Sensing
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Solution Overview
Problem
Series elastic actuators face challenges in compact design and adjustable rigidity due to the separate requirement of a reduction gear and spring, making it difficult to manufacture them to a predetermined size while maintaining flexibility and precise torque measurement.
Innovation Solution
The implementation of an elastic gear module with a gear, output body, and elastic body, where the elastic body is made of non-metallic material like urethane, and is designed with a mounting recess and insertion portions to transmit rotational force without mechanical backlash, allowing for adjustable rigidity and compact size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate reduction gear and spring are used for torque measurement, then the actuator can achieve flexible adaptation to external forces, but the device size increases and rigidity adjustment becomes difficult
Solution Approach 1:
The patent combines the reduction gear and spring into a single integrated elastic gear module. The elastic body is formed as an integral part of the gear structure, eliminating the need for separate components. This merging reduces the overall actuator size while maintaining the flexibility to adapt to external forces through the elastic deformation of the integrated elastic gear module.
Solution Approach 2:
The elastic gear module serves multiple functions simultaneously: it acts as both the reduction gear and the spring for torque measurement. The elastic body provides both the mechanical advantage of gear reduction and the compliant torque sensing capability, making the component universal and multi-functional.
2Measurement precision
If a separate reduction gear and spring are used, then torque measurement is possible, but additional space and complex configuration are required
Solution Approach 1:
The patent merges the torque measurement function into the gear structure itself. The elastic body is formed as an integral part of the gear, with insertion portions that engage with the gear teeth. This integration eliminates the need for separate spring components and complex arrangements, simplifying the overall device configuration while maintaining precise torque measurement capability through elastic deformation.
3Measurement precision
If traditional spring design is used, then torque measurement is achieved, but rigidity adjustment is difficult during manufacturing
Solution Approach 1:
The patent enables rigidity adjustment by changing the geometric parameters of the elastic body during manufacturing. The rigidity can be controlled by modifying the thickness, material properties, or structural configuration of the elastic body in the elastic gear module. This allows for flexible rigidity adjustment without requiring different spring components, simplifying the manufacturing process.
4Volume of moving object
If compact design is pursued, then size is reduced, but separate spring and gear components cannot be accommodated
Solution Approach 1:
The patent achieves compact design by merging the reduction gear and spring into a single elastic gear module. The elastic body is formed as an integral part of the gear structure, allowing both components to occupy the same spatial envelope. This integration dramatically reduces the actuator size compared to designs using separate spring and gear components.
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 enables a compact series elastic actuator with adjustable rigidity, enhancing flexibility and precision in torque measurement, and simplifies the design process by using non-metallic materials and innovative structural features.
Implementation Method 1
a plurality of elastic bodies 230 received in the mounting recess 211, including non-metal elastic material and spaced apart from each other in a circumferential direction
Data Source
AI summary
A series elastic actuator includes a gear configured to rotate, a mounting recess formed on a first surface of the gear, a plurality of elastic bodies configured to be received in the mounting recess that are made of a non-metal elastic material and spaced apart from each other in a circumferential direction, an output body configured to cover the first surface of the gear, and at least one insertion portion configured to protrude from the output body to be inserted between a pair of adjacent elastic bodies or inserted through the elastic bodies.