Actuator Arrangement Torque Transfer Compact Design

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Solution Overview

Problem

Existing actuators for robotic arms face challenges in achieving high precision and high torque while maintaining a compact and lightweight design, often resulting in large axial extent and low efficiency.

Innovation Solution

The actuator design incorporates a motor with a housing and drive shaft, a first torque transfer device to transfer torque from the drive shaft to a second shaft, and an output torque transfer device to transfer torque from the second shaft to the motor housing, allowing for compactness and high mechanical advantage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a motor and gear box are designed and built separately, then the gear box can be optimized for torque multiplication, but the axial extent of the overall actuator arrangement becomes large

Engineering Contradiction:
ImprovetorqueVSAvoidaxial extent
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

The patent integrates the motor and gear box into a single unified actuator arrangement, where the motor is positioned within the gear box structure. This merging eliminates the need for separate motor and gear box assemblies, thereby reducing the overall axial extent while maintaining torque multiplication capabilities through the integrated design.

Inventive Principle:
Principle #5Merging (Combining)

2Force

If the gear box is designed to multiply torque, then high torque output is achieved, but the device complexity increases

Engineering Contradiction:
ImprovetorqueVSAvoiddevice complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

The actuator housing serves multiple functions: it acts as the gear box enclosure, provides mounting structures for the motor and gears, and serves as part of the torque transmission path. This multi-functionality reduces the number of separate components needed, thereby simplifying the overall device complexity while maintaining torque multiplication.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Force

If traditional motor and gear box arrangements are used, then torque can be increased, but the precision of movement decreases due to high inertia

Engineering Contradiction:
ImprovetorqueVSAvoidprecision of movement
Core Design Contradiction:
ForceVSMeasurement precision

Solution Approach 1:

The patent employs a planetary gear mechanism that provides high torque multiplication with relatively low inertia. The planetary arrangement allows for compact gear teeth engagement and efficient torque transmission, reducing the inertial effects that would otherwise degrade movement precision while maintaining high torque output capability.

Inventive Principle:
Principle #15Dynamics

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 more compact actuator with improved mechanical advantage, precision, and efficiency, suitable for use in robotic arms without increasing size or weight.

Implementation Method 1

a motor having a housing and a drive shaft, the motor arranged to rotate the drive shaft relative to the housing about a drive shaft axis

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a first torque transfer device arranged to transfer torque from the drive shaft to a second shaft

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Implementation Method 3

an output torque transfer device arranged to transfer torque from the second shaft to the housing of the motor

Methodology Applied
Scientific EffectMechanical advantage: Mechanical Advantage

Data Source

PatentEP3911874B1Actuator arrangement
Publication Date: 2025.03.05 EXODUS ACTUATION SOLUTIONS INC CA
  • EP3911874B1 patent drawingFigure 1
  • EP3911874B1 patent drawingFigure 2
  • EP3911874B1 patent drawingFigure 3

AI summary

An actuator comprising: a motor having a housing and a drive shaft, the motor arranged to rotate the drive shaft relative to the housing about a drive shaft axis; a first torque transfer device arranged to transfer torque from the drive shaft to a second shaft, the second shaft being rotatable about a second shaft axis parallel to and radially spaced from the drive shaft axis; and an output torque transfer device arranged to transfer torque from the second shaft to the housing of the motor; wherein, upon rotation of the drive shaft relative to the motor housing, the housing of the motor is arranged to rotate relative to the position of the second shaft axis.