Speed Reducer Shaft Heat Conduction for Robot Gear Cooling

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Solution Overview

Problem

The existing gear mechanisms in cooperative robots experience temperature rise issues due to frictional heat, leading to potential seizure and reduced product life, with insufficient heat dissipation mechanisms.

Innovation Solution

Incorporating a shaft with a high thermal conductivity portion extending over its entire axial length, which actively transfers and dissipates heat generated between gears, and using a support member with high thermal conductivity to enhance heat release.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If internal tooth pins with higher thermal conductivity than the case are used, then heat transmission to internal tooth pins is improved, but the overall heat dissipation capability remains insufficient because the volume of internal tooth pins is very small compared to the volume of the case

Engineering Contradiction:
Improvetemperature rise suppressionVSAvoidheat dissipation efficiency
Core Design Contradiction:
TemperatureVSLoss of energy

Solution Approach 1:

The invention changes the thermal conductivity parameter of the shaft by providing a shaft-side high thermal conductivity portion with thermal conductivity higher than the second gear. This parameter change enables the shaft to actively transmit heat from the meshing region to its end portions, fundamentally improving the heat dissipation capability of the gear mechanism.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The shaft-side high thermal conductivity portion acts as an intermediary heat transmission path between the meshing region (first gear and second gear) and the external environment. It mediates the heat flow by conducting heat from the gear meshing area through the shaft to its end portions, where heat can be dissipated more effectively.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If the shaft has high thermal conductivity to transfer heat, then heat transmission capability is improved, but the shaft material selection and manufacturing complexity increase

Engineering Contradiction:
Improveheat transfer efficiencyVSAvoidshaft manufacturing
Core Design Contradiction:
TemperatureVSEase of manufacture

Solution Approach 1:

The invention applies local quality by providing a shaft-side high thermal conductivity portion that extends over the entire axial length of the shaft. This localized high thermal conductivity region is specifically positioned where heat transmission is most needed, while the rest of the shaft structure can maintain its original material properties and manufacturing simplicity.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The shaft is constructed as a composite structure with a shaft-side high thermal conductivity portion having different material properties than the base shaft material. This composite approach allows the shaft to combine the thermal conductivity benefits of high-conductivity materials with the mechanical strength and manufacturability of the base material.

Inventive Principle:
Principle #40Composite materials

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 efficiently suppresses temperature rise within the gear mechanism, extending product life and reducing maintenance costs by effective heat management.

Implementation Method 1

the thermal conductivity of the shaft-side high thermal conductivity portion is higher than the thermal conductivity of the second gear... the heat generated by engagement between the first gear and the second gear and the heat generated between the second gear and the shaft can be actively transferred to the shaft

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4187125A1Gear mechanism and robot
Publication Date: 2023.05.31 NABTESCO CORP
  • EP4187125A1 patent drawingFigure 1
  • EP4187125A1 patent drawingFigure 2
  • EP4187125A1 patent drawingFigure 3

AI summary

A speed reducing mechanism (1B) according to one embodiment of the invention includes a case (2), internal tooth pins (6), an oscillating gear (11, 12) meshing with the internal tooth pins (6), an input crankshaft (8) transmitting a rotational force to the oscillating gear (11, 12), and an output shaft (9) to which a rotational force of the oscillating gear (11, 12) is transmitted. One of the shafts (8, 9) at least partially has a shaft-side high thermal conductivity portion that extends over the entire axial length of the shaft (8, 9) and has a thermal conductivity higher than the thermal conductivity of the oscillating gear (11, 12).