Motor-Sensor Coupling With Damped Intermediate Part for Angle Accuracy

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Solution Overview

Problem

Existing electric motor systems with clutches and angle sensors face challenges in achieving a precise, shock-absorbing, and torque-transmitting connection between the rotor shaft and sensor shaft, particularly in maintaining high-quality angle detection and protecting the sensor from mechanical shocks and jerks.

Innovation Solution

The electric motor design features a shaft-centric connection using coupling parts with an intermediate disk part that absorbs shocks and torque, where the coupling parts are connected to the rotor and sensor shafts with axially aligned bolts and a plastic layer to dampen vibrations, and an electromagnetically actuated brake for counter-holding during power failures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a rigid coupling is used to connect the rotor shaft and sensor shaft, then torque transmission is efficient, but the sensor is exposed to mechanical shocks and jerks that reduce measurement precision

Engineering Contradiction:
Improvesensor protection from mechanical shocksVSAvoidangle detection quality
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent introduces an intermediate coupling part with elastomeric receptacles that act as a mediator between the rotor shaft and sensor shaft. This intermediate element absorbs mechanical shocks and jerks while still transmitting torque, thereby protecting the sensor from direct mechanical impacts and maintaining measurement precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The coupling device combines rigid coupling parts with elastomeric (flexible) materials in the intermediate part. This composite structure allows the rigid parts to transmit torque efficiently while the elastomeric material provides shock absorption and vibration damping, resolving the contradiction between torque transmission and shock protection.

Inventive Principle:
Principle #40Composite materials

2Object-affected harmful factors

If an elastic coupling is used to protect the sensor from shocks, then the sensor is protected from mechanical jerks, but torque transmission efficiency is reduced

Engineering Contradiction:
Improvemechanical shocks to sensorVSAvoidtorque transmission capability
Core Design Contradiction:
Object-affected harmful factorsVSPower

Solution Approach 1:

The coupling device applies different material properties to different parts: the coupling parts are rigid for efficient torque transmission, while only the intermediate part contains elastomeric receptacles for shock absorption. This localized application of elastic properties protects the sensor without significantly compromising overall torque transmission efficiency.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If a complex coupling structure is used to achieve both shock absorption and precise angle measurement, then measurement quality is improved, but device complexity increases

Engineering Contradiction:
Improveangle sensor measurement qualityVSAvoidcoupling structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The coupling device is divided into distinct segments: two coupling parts and an intermediate part with elastomeric receptacles. This segmentation allows each component to perform its specific function (torque transmission or shock absorption) independently, simplifying the design and manufacturing of each individual part while achieving the combined performance.

Inventive Principle:
Principle #1Segmentation

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 enables high-precision angle detection while protecting the sensor from mechanical shocks and jerks, allowing for efficient torque transmission and ensuring the sensor's stability and accuracy.

Implementation Method 1

the intermediate part is designed to dampen shocks or torque surges

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

at least the surface areas of the bolts projecting into the recesses of the respective collar region are coated with a plastic layer, in particular a PEEK or Teflon layer

Methodology Applied
Scientific EffectViscoelastic damping: Viscoelasticity

Implementation Method 3

an electromagnetically actuated brake for counter-holding during power failures

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3788268B1Coupling for an electric motor and electric motor with a coupling between the rotor shaft and the shaft of an angle sensor
Publication Date: 2023.11.22 SEW EURODRIVE GMBH & CO KG
  • EP3788268B1 patent drawingFigure 1
  • EP3788268B1 patent drawingFigure 2
  • EP3788268B1 patent drawingFigure 3

AI summary

A clutch for an electric motor and an electric motor having a rotor shaft, an angle sensor and a clutch are disclosed, where the clutch comprises: - a first clutch portion, in particular for connection for conjoint rotation with a rotor shaft of the electric motor, - a second clutch portion, in particular for connection for conjoint rotation with a shaft, in particular a sensor shaft of an angle sensor of the electric motor; - and an intermetiate portion, wherein the intermediate portion is interlockingly connected at its circumference to both the first and the second coupling portions.