Series Elastic Actuator Buffer Layout for Easy Spring Replacement

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Solution Overview

Problem

The performance of series elastic actuators (SEAs) is restricted by the spring characteristics of the elastic elements, requiring frequent replacement and making it labor-intensive to attach and remove the elastic elements, especially when disposed between the speed reducer and the joint portion.

Innovation Solution

A drive device comprising a motor portion, a speed reducer, and a buffer device with an elastic portion, where at least a part of the buffer device is disposed on a side opposite to the motor portion and the speed reducer with the drive target interposed therebetween, allowing for easy attachment and removal of the buffer device.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the elastic element is disposed between the speed reducer and the joint portion, then the motor and speed reducer are protected from damage, but it becomes labor-intensive to attach and remove the elastic element

Engineering Contradiction:
Improveprotection of motor and speed reducerVSAvoidattachment and removal of elastic element
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The drive device is divided into modular components: motor portion, speed reducer, and buffer device. The buffer device with elastic portion can be independently attached and removed from the drive target, while the motor and speed reducer remain fixed. This segmentation allows easy maintenance of the elastic element without affecting other components.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The buffer device serves as an intermediary component between the speed reducer and the drive target. It includes the elastic portion that can be easily attached and removed, while still providing the protective function. The buffer device acts as a mediator that isolates the motor and speed reducer from direct exposure to external forces.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the elastic element is disposed between the speed reducer and the joint portion, then force control and shock absorption are achieved, but replacement of the elastic element requires labor and time

Engineering Contradiction:
Improveforce control and shock absorptionVSAvoidtime for replacement
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The buffer device is designed as a separate, self-contained module that can be quickly replaced. The elastic portion is integrated into the buffer device, which can be attached to or removed from the drive target independently. This modular design significantly reduces the time required for replacement while maintaining force control and shock absorption functions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The buffer device is designed to be dynamically attachable and detachable. The connection mechanism allows for quick attachment and removal operations, enabling rapid replacement of the elastic element without requiring complex disassembly procedures. This dynamic design reduces maintenance time while preserving the protective functions.

Inventive Principle:
Principle #15Dynamics

3Ease of operation

If the buffer device is disposed on the side opposite to the motor portion and speed reducer with the drive target interposed, then easy attachment and removal is achieved, but the structural configuration becomes more complex

Engineering Contradiction:
Improveattachment and removal of buffer deviceVSAvoidstructural configuration
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The drive device is segmented into distinct functional modules: motor portion, speed reducer, and buffer device. The buffer device is positioned on the opposite side of the drive target, creating a clear separation between the power transmission components and the elastic buffer component. This segmentation simplifies the attachment and removal process while the modular structure manages the overall system complexity.

Inventive Principle:
Principle #1Segmentation

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 proposed solution facilitates easy attachment and removal of the buffer device, reducing labor and enabling efficient replacement or inspection, while maintaining the actuator's performance and precision.

Implementation Method 1

The buffer device outputs the torque input from the speed reducer to the drive target from an output end part via an elastic portion

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4541970A1Drive device, work machine
Publication Date: 2025.04.23 YANMAR HLDG CO LTD
  • EP4541970A1 patent drawingFigure 1
  • EP4541970A1 patent drawingFigure 2
  • EP4541970A1 patent drawingFigure 3

AI summary

[Problem] To easily attach and remove a buffer device of a drive device. [Solution] A drive device 500 for rotationally moving a drive target M2 includes a motor portion 1, a speed reducer 2 for reducing a torque input from the motor portion 1, and a buffer device 3 for outputting the torque input from the speed reducer 2 to the drive target M2 via an elastic portion 33. At least a part of the buffer device 3 is disposed on a side opposite to the motor portion 1 and the speed reducer 2 with the drive target M2 interposed therebetween.