Gearbox Coupling Sleeve Axial Position Detection Using Resolver

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Solution Overview

Problem

Current coupling arrangements in gearboxes for vehicles, particularly heavy goods vehicles, are cumbersome due to the need for multiple components, including separate position indicator devices, which increase weight and reduce reliability.

Innovation Solution

A coupling arrangement that utilizes an electrical machine's position indicator device, such as a resolver, to detect both the angular and axial positions of the coupling sleeve, eliminating the need for separate detection components and reducing the overall component count, weight, and improving reliability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a separate position indicator device is added to detect the axial position of the coupling sleeve, then the detection accuracy is improved, but the device complexity and weight increase

Engineering Contradiction:
Improveposition detection accuracyVSAvoidcomponent count
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The resolver, originally designed to detect the angular position of the rotor, is made to perform dual functions by also detecting the axial position of the coupling sleeve. The resolver stator remains stationary while the resolver rotor is coupled to the coupling sleeve, allowing the same device to measure both rotational and axial positions through its standard signal processing circuitry.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the position indicator device for the electrical machine with the detection function for the coupling sleeve axial position. By integrating the resolver rotor with the coupling sleeve and using the existing resolver stator and signal processing circuitry, two detection functions are merged into a single device, eliminating the need for a separate position indicator.

Inventive Principle:
Principle #5Merging (Combining)

2Measurement precision

If multiple separate components are used for position detection, then the detection coverage is improved, but the reliability decreases due to more potential failure points

Engineering Contradiction:
Improveposition detection capabilityVSAvoidsystem reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The resolver is designed to perform multiple detection functions simultaneously - detecting both the angular position of the rotor and the axial position of the coupling sleeve. This multi-functionality reduces the total number of separate detection components, thereby minimizing potential failure points while maintaining comprehensive position detection capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Measurement precision

If the resolver stator is made axially displaceable to track the coupling sleeve position, then the detection accuracy is improved, but the device complexity increases

Engineering Contradiction:
Improveaxial position detection accuracyVSAvoidresolver structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of making the resolver stator axially displaceable to track the coupling sleeve (which would increase complexity), the patent inverts the approach by making the resolver rotor move axially with the coupling sleeve while keeping the stator stationary. This allows the same detection principle to work with a simpler structure, as the stationary stator and rotating rotor configuration is the standard, simpler design.

Inventive Principle:
Principle #13The other way round (Inversion)

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 simplifies the coupling arrangement by using a single position indicator device for both the electrical machine and coupling sleeve, reducing weight and component failure risks, while maintaining precise position detection for improved gearbox operation.

Implementation Method 1

The position indicator device is a resolver comprising at least one resolver rotor arranged on the coupling sleeve. The resolver can be likened to a small electric machine, where an alternating excitation signal creates an alternating feedback signal with different amplitude.

Methodology Applied
Scientific EffectResolver: Electromagnetic Induction

Data Source

PatentEP3445991B1A coupling arrangement for a gearbox
Publication Date: 2021.03.03 SCANIA CV AB
  • EP3445991B1 patent drawingFigure 1
  • EP3445991B1 patent drawingFigure 2
  • EP3445991B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a coupling arrangement for a gearbox (8), comprising a coupling sleeve (24), which is axially displaceable between a first and second position, a first and second rotatable element (26, 28), which are connectable and disconnectable to each other by means of the coupling sleeve (24), an electrical machine (16) connected to one of the first and second rotatable element (26, 28), and a position indicator device (70) for detecting the angular position of a rotor of the electrical machine (16). The position indicator device (70) also is arranged to detect the axial position of the coupling sleeve (24).