Industrial Robot Clutch With Friction Torque Return Positioning

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Solution Overview

Problem

Existing clutches for industrial robots fail to prevent the robot from dropping a weight it is holding after decoupling and do not reliably return to the previous relative coupling position without human intervention.

Innovation Solution

A clutch design featuring a hub, cam, spring plate, and output flange with grooves and recesses for transmission elements, allowing for a predetermined friction torque to maintain load support and precise return to a predefined position, even after decoupling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a friction clutch is used to protect the robot from torque overload, then the robot is protected from breakdown, but the relative position of the input and output of the clutch is shifted and lost, requiring recalibration

Engineering Contradiction:

Improveprotection from torque overloadVSAvoidrelative position accuracy

Core Design Contradiction:

ReliabilityVSMeasurement precision

Solution Approach 1:

A cam mechanism acts as an intermediary between the input and output flanges, guiding the transmission elements through grooves to ensure precise return to the original relative position after overload protection activates

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The cam profile is designed with specific geometric parameters that change the transmission path of the elements, allowing the clutch to return to a predetermined position with high precision after decoupling

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If a ball-spring-cam clutch is used to allow unique return position, then the relative position can be restored, but residual torque transmitted to the load is minimal causing the robot to collapse under its own weight

Engineering Contradiction:

Improvereturn position accuracyVSAvoidresidual torque

Core Design Contradiction:

Measurement precisionVSForce

Solution Approach 1:

The clutch mechanism transitions between different dynamic states: during normal operation it transmits full torque, during overload it decouples, and during return it maintains controlled residual torque through friction to support the robot's weight without collapsing

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The friction between transmission elements and cam grooves, which could be considered a loss mechanism, is converted into a beneficial residual torque that prevents the robot from collapsing under its own weight after decoupling

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the clutch completely decouples the load from the motor, then protection from torque overload is achieved, but the robot cannot hold the weight it is carrying

Engineering Contradiction:

Improveprotection from torque overloadVSAvoidload holding capability

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

Instead of complete decoupling, the clutch provides partial coupling through controlled friction that generates sufficient residual torque to hold the robot's weight while still protecting from excessive overload torque

Inventive Principle:

Principle #16Partial or excessive action

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

Ensures the robot holds the weight in any position and reliably returns to the previous relative coupling position, preventing free rotation and ensuring reproducible results.

Implementation Method 1

a plurality of springs arranged in the angular direction between the spring plate and the output flange, wherein the plurality of springs allow the spring plate to move axially with respect to the output flange and/or the cam

Methodology Applied

Scientific EffectSpring force: Spring

Implementation Method 2

the clutch is configured to, during use in the second state, provide a predetermined friction torque through friction between the transmission elements and a surface of the cam, between the sliding bearing and the output flange, or both

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS12404904B2Clutch, industrial robot and the use thereof

Publication Date: 2025.09.02 UNIV GENT

AI summary

A clutch comprising a hub and a cam connected to the hub, said cam comprising a ring-shaped part having grooves formed on a bottom surface of the ring-shaped part; a spring plate having recesses formed on a top surface of the spring plate; an output flange and a part of a roller bearing connected to each other, said output flange comprising a ring-shaped part configured to accommodate the spring plate, a plurality of transmission elements arranged in an angular direction between the spring plate and the cam; a plurality of springs arranged in the angular direction between the spring plate and the output flange; and a sliding bearing provided at an interface between the hub and the output flange, wherein the clutch is configured to be changed between first and second states. A high-speed industrial robot capable of moving on a plurality of axes, and use thereof.