Series Elastic Actuator with Integrated Elastic Gear Module
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Series elastic actuators face challenges in compact design and adjustable rigidity, particularly when manufactured to a predetermined size, and require additional space and configuration for separate reduction gears and springs, making it difficult to achieve precise control over driving rigidity.
Innovation Solution
The proposed series elastic actuator incorporates an elastic gear module with a mounting recess on the gear, an elastic body, and radial bearings to support the shaft, allowing for compact design and reinforced gear rigidity, while ensuring smooth rotation of the shaft connected to the output body.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate reduction gear and spring are provided in the series elastic actuator, then torque measurement and flexible adaptation to external forces are achieved, but additional space and complex configuration are required
Solution Approach 1:
The patent merges the reduction gear and spring into an integrated elastic gear module. The spring is positioned within the gear structure, combining torque reduction and elastic energy storage functions in a single compact component, thereby eliminating the need for separate reduction gear and spring assemblies.
Solution Approach 2:
The spring is nested within the gear structure, with the spring housed inside the gear's internal cavity. This nesting arrangement allows the spring to be contained within the gear's footprint, significantly reducing the overall actuator volume while maintaining both gear reduction and elastic compliance functions.
2Volume of stationary object
If the series elastic actuator is manufactured to a predetermined size, then compact design is achieved, but rigidity adjustment becomes difficult
Solution Approach 1:
The patent introduces local quality variations through different gear modulus values at different radial positions. The gear has a first modulus for the tooth root portion and a second modulus for the tooth surface portion, allowing localized rigidity control within the compact gear structure. This enables rigidity adjustment without increasing overall actuator size.
3Ease of operation
If radial bearings are added to support the shaft, then shaft rotation smoothness is improved, but device complexity increases
Solution Approach 1:
The gear structure serves multiple functions simultaneously: it provides torque reduction, stores elastic energy, supports the shaft via integrated bearing mounting surfaces, and enables rigidity adjustment through modulus variation. By making the gear multi-functional, additional support elements are minimized while maintaining shaft rotation smoothness.
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 configuration enables a compact series elastic actuator with enhanced gear rigidity and smooth shaft rotation, improving the efficiency and reliability of the actuator system.
Implementation Method 1
an elastic body to transmit a rotational force of the gear to the output body
Data Source
AI summary
A series elastic actuator includes a gear, a mounting recess formed in the gear, an elastic body provided in the mounting recess, an output body, a through-hole penetrating the gear, a shaft passing through the through-hole, a pair of bearings to radially support the shaft, and a pair of bearing mounting recesses to receive the pair of bearings. The gear is configured to rotate by a rotational power source. A rotation force of the gear is transmitted to the gear by the elastic body. The through-hole may extend in an axial direction, and the pair of bearings may be spaced apart from each other in the axial direction. The pair of bearing mounting recesses may be formed at opposite ends of the through-hole.