Robot Joint Grease Cooling Using Base-Side Motor Rotation

Solution Overview

Problem

The rapid deterioration of grease in robot joints at higher temperatures poses a challenge, as existing solutions that provide cooling mechanisms increase costs and require larger motor sizes.

Innovation Solution

A control device that obtains temperature information, specifies joints requiring cooling, and controls motors to turn adjacent joints for a given time to cool the grease without the need for additional cooling devices, thereby suppressing grease deterioration with a simple structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If cooling means is provided for each motor joint, then grease deterioration is suppressed, but device complexity and cost increase

Engineering Contradiction:

Improvegrease deterioration suppressionVSAvoidcooling means structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The robot system cools itself by utilizing the motors of joints located on the base side to perform cooling actions. When a joint on the articulated arm side requires cooling, the system controls the motor of a joint on the base side to execute turning operations that generate cooling airflow, eliminating the need for dedicated cooling devices at each joint.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

Motors on the base side perform dual functions: their primary function for robot operation and an additional cooling function for joints on the articulated arm side. This multi-functionality allows the same motor to serve both operational and thermal management purposes, reducing overall system complexity.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If cooling means is provided for each motor joint, then grease deterioration is suppressed, but motor size must be enlarged

Engineering Contradiction:

Improvegrease deterioration suppressionVSAvoidmotor size

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The robot system cools itself by utilizing the motors of joints located on the base side to perform cooling actions. When a joint on the articulated arm side requires cooling, the system controls the motor of a joint on the base side to execute turning operations that generate cooling airflow, eliminating the need for dedicated cooling devices at each joint.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The cooling function is extracted from the joint that requires cooling and transferred to a different joint (on the base side) that performs the cooling action. This separation allows the joint needing cooling to remain compact while the cooling action is performed by a motor already present in the system.

Inventive Principle:

Principle #2Taking out (Extraction)

3Temperature

If additional cooling devices are added, then grease cooling effectiveness is improved, but cost increases

Engineering Contradiction:

Improvegrease cooling effectivenessVSAvoidcooling device quantity

Core Design Contradiction:

TemperatureVSDevice complexity

Solution Approach 1:

The robot system cools itself by utilizing the motors of joints located on the base side to perform cooling actions. When a joint on the articulated arm side requires cooling, the system controls the motor of a joint on the base side to execute turning operations that generate cooling airflow, eliminating the need for dedicated cooling devices at each joint.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The system changes the operational parameters of existing motors (adding intermittent turning operations) to generate cooling airflow, rather than introducing new cooling devices. This parameter change approach maintains effectiveness while avoiding additional hardware costs.

Inventive Principle:

Principle #35Parameter changes

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 approach effectively cools the grease in robot joints, reducing deterioration and wear without the need for additional cooling devices, thus maintaining efficiency and cost-effectiveness.

Implementation Method 1

the motor control unit is configured to control the motor of at least one of the joints that is located on a side of the base from the specified joint so as to turn the joint on the side of the base from the specified joint for a given time

Methodology Applied

Scientific EffectForced Convection: Forced Convection

Data Source

PatentUS11571822B2Control device, grease cooling method and management device

Publication Date: 2023.02.07 FANUC LTD

AI summary

A control device configured to control a robot including an articulated arm having a plurality of joints each provided with a motor and turned by driving of the motor and a base supporting the articulated arm includes: a temperature information obtaining unit configured to obtain temperature information about the plurality of joints; a joint specifying unit configured to specify one of the joints that requires cooling, based on the obtained temperature information about the plurality of joints; and a motor control unit configured to control the motor of each of the plurality of joints, wherein, when the joint specifying unit specifies one of the joints, the motor control unit controls the motor of at least one of the joints that is located on a side closer to the base from the specified joint so as to turn the joint on the base side for a given time.