Drum Motor Angle Measurement via Fluid-Tight Capsule

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Solution Overview

Problem

Drum motors face challenges with heat dissipation due to their compact design, limiting their performance, especially in high-power applications where the angle measuring unit's specified length and diameter restrict heat dissipation, thereby limiting their range of use.

Innovation Solution

The angle measuring unit is encapsulated within a fluid-tight capsule, allowing it to operate in a cooling fluid like oil, which enhances heat dissipation and enables the electric drive unit to handle higher power levels while maintaining accurate angle measurement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the drum motor is designed with a compact structure to reduce size, then the device complexity is reduced, but heat dissipation becomes difficult and thermal stability deteriorates

Engineering Contradiction:
Improvedrum motor sizeVSAvoidthermal stability
Core Design Contradiction:
Volume of moving objectVSTemperature

Solution Approach 1:

A fluid-tight capsule filled with cooling fluid (oil or water) is introduced as an intermediary cooling medium between the electric drive unit and the external environment. The capsule allows efficient heat transfer from the motor to the fluid while maintaining a compact structure, resolving the contradiction between small size and heat dissipation capability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If the angle measuring unit is placed outside the fluid-tight capsule, then the device complexity is reduced, but the measurement precision deteriorates due to interference from cooling fluid

Engineering Contradiction:
Improvecapsule structureVSAvoidangle measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

A magnetically coupled transmission mechanism acts as an intermediary between the angle measuring unit and the rotor shaft. Magnetic fields transmit rotational position information through the fluid-tight capsule wall without physical penetration, eliminating cooling fluid interference while maintaining measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces direct mechanical coupling (which would require penetrating the capsule and exposing sensors to cooling fluid) with magnetic field coupling. This substitution allows the angle measuring unit to remain isolated in the dry environment inside the capsule while still accurately measuring rotor shaft position.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Power

If the electric drive unit operates at higher power levels, then the productivity increases, but heat dissipation becomes more difficult and thermal stability deteriorates

Engineering Contradiction:
Improveelectric drive powerVSAvoidthermal stability
Core Design Contradiction:
PowerVSTemperature

Solution Approach 1:

The cooling fluid in the fluid-tight capsule serves as an intermediary heat transfer medium that efficiently carries away heat generated by high-power operation. The fluid circulation system maintains thermal stability even when the electric drive unit operates at elevated power levels, enabling higher productivity without thermal runaway.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution allows drum motors to operate with higher mechanical power, up to 1000 watts, and supports wider application ranges, including modern conveyor systems with belt widths over 600 mm, while maintaining thermal stability and compatibility with existing feedback systems.

Implementation Method 1

a cooling fluid, for example an oil, is provided in the drum tube for cooling the electric drive unit

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 2

a cooling fluid, for example an oil, is provided in the drum tube for cooling the electric drive unit

Methodology Applied
Scientific EffectConvection: Convection

Data Source

PatentEP3138791B1Drum motor and sensor cartridge for a drum motor
Publication Date: 2020.05.06 INTERROLL HLDG
  • EP3138791B1 patent drawingFigure 1
  • EP3138791B1 patent drawingFigure 2
  • EP3138791B1 patent drawingFigure 3

AI summary

Drum motor (300) with a drum tube (301) extending along a longitudinal axis (303), an electric drive unit (200) arranged in the drum tube (301) with a stator (201) and a rotor shaft (203), an angle measuring unit (101) arranged in the drum tube (301) such that it can detect an angle of rotation between the stator (201) and the rotor shaft (203), wherein the angle measuring unit (101) is arranged within a fluid-tight capsule (120) so that the angle measuring unit can be operated in a cooling fluid (FL) which is to be introduced into a drum tube (301) of the drum motor (300) for the purpose of cooling the electric drive unit (200).