Torque Arm with Meandering Ribs for Angle Sensor Mounting

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Solution Overview

Problem

Existing electric motor designs face challenges in achieving simplicity and cost-effectiveness while maintaining precise angular position detection and torsional rigidity, particularly in compensating for manufacturing tolerances and radial forces.

Innovation Solution

The electric motor incorporates a fan cover and rotor shaft with an angle sensor mounted rotatably, utilizing a torque arm with inner and outer rings connected via webs, allowing for elastic compensation of radial forces and maintaining high torsional rigidity in the circumferential direction, enabling easy assembly and production with inexpensive components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a rigid connection is used to connect the angle sensor housing to the fan cover, then torsional rigidity is improved, but manufacturing tolerances cannot be compensated

Engineering Contradiction:
Improvetorsional rigidityVSAvoidtolerance compensation
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The torque arm transitions from a rigid connection to a dynamic, flexible connection that can adapt to manufacturing tolerances. The flexible structure allows for elastic deformation in radial and axial directions while maintaining torsional rigidity for accurate angle detection.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The torque arm's flexibility parameters are optimized to provide the right balance: soft in radial and axial directions for tolerance compensation, but stiff in the circumferential direction for maintaining torsional rigidity and accurate angle sensor readings.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If a flexible connection is used to compensate for tolerances, then ease of manufacture is improved, but torsional rigidity deteriorates

Engineering Contradiction:
Improvetolerance compensationVSAvoidtorsional rigidity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The torque arm exhibits different mechanical properties in different directions: flexible in radial and axial directions for ease of manufacture and tolerance compensation, but rigid in the circumferential direction for maintaining torsional stiffness. This directional differentiation of mechanical properties resolves the contradiction.

Inventive Principle:
Principle #3Local quality

3Measurement precision

If the angle sensor housing is rigidly connected to the fan cover, then measurement precision is improved, but device complexity increases due to special torque supports

Engineering Contradiction:
Improveangular position detectionVSAvoidtorque support structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The torque arm's flexible structure automatically compensates for manufacturing tolerances through its own elastic deformation, eliminating the need for additional adjustment mechanisms or complex torque supports. The structure serves its own alignment and tolerance compensation functions.

Inventive Principle:
Principle #25Self-service

4Device complexity

If radial forces are not compensated, then device complexity is reduced, but measurement precision deteriorates due to reaction torques

Engineering Contradiction:
Improvetorque support structureVSAvoidangular position detection
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The torque arm acts as an intermediary element between the angle sensor housing and the fan cover. It mediates the transmission of forces and torques, allowing radial forces to be absorbed elastically while transmitting only the necessary rotational position information to the angle sensor, thereby protecting measurement precision.

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 design effectively compensates for manufacturing tolerances and radial forces, achieving high torsional rigidity and efficient damping of vibrations, while allowing for accurate angle detection with reduced production complexity and cost.

Implementation Method 1

the outer ring is connected to an inner ring via inner webs, wherein the outer ring is deflected off-center relative to the inner ring in a radially directed manner, by means of which radial forces can be absorbed elastically

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

an angle sensor, wherein a housing of the angle sensor is connected to a torque arm which is connected to the fan cover

Methodology Applied
Scientific EffectAngular position detection:

Data Source

PatentEP4115503B1Electric motor with fan cover and rotor shaft rotatable to fan cover and angle sensor
Publication Date: 2024.08.07 SEW EURODRIVE GMBH & CO KG
  • EP4115503B1 patent drawingFigure 1
  • EP4115503B1 patent drawingFigure 2
  • EP4115503B1 patent drawingFigure 3

AI summary

The invention relates to an electric motor having a fan guard (9) and rotor shaft (5) mounted rotatably relative to the fan guard (9) and angle sensor (2), a housing of the angle sensor (2) being connected to a torque support (1) which is connected to the fan guard (9), the torque support (1) having ribs (21, 24) that are shaped in a meandering manner.