CVT Movable Sheave Position Sensing With Hall Flux Detection

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Solution Overview

Problem

Existing continuously variable transmission devices face limitations in accurately detecting the position of the movable sheave due to separation of the actuator and sensor, leading to reduced accuracy.

Innovation Solution

A configuration where a Hall IC sensor, integrated with a magnet, directly detects the magnetic flux density components in the x and z directions to determine the position of the movable sheave, allowing for precise displacement measurement without contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the actuator and sensor are separated and the sensor detects the position indirectly via the arm, then the influence of dimensional errors and assembly errors is reduced, but the position detection accuracy is still limited because the movable sheave position is not directly detected

Engineering Contradiction:
Improveposition detection accuracyVSAvoiddetection mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates the sensor directly onto the movable sheave, merging the detection component with the measured object. This direct integration eliminates intermediate transmission elements (such as the arm) that could introduce errors, enabling direct position detection of the movable sheave while maintaining system compactness

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent introduces a magnet as an intermediary element attached to the movable sheave, which interacts with the Hall IC sensor to enable non-contact position detection. This intermediary approach allows direct measurement without mechanical contact, eliminating wear and improving detection accuracy

Inventive Principle:
Principle #24Intermediary (Mediator)

2Measurement precision

If the sensor directly detects the movable sheave position, then the position detection accuracy is improved, but the device structure becomes more complex

Engineering Contradiction:
Improveposition detection precisionVSAvoidsensor integration complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces mechanical position detection mechanisms with a magnetic field-based Hall IC sensor system. This substitution eliminates complex mechanical linkages and contact-based detection, achieving direct position measurement through non-contact magnetic field sensing while simplifying the overall mechanical structure

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

Solution Approach 2:

The patent changes the detection parameter from mechanical position (requiring physical contact) to magnetic field intensity (detectable by Hall IC). By detecting the magnetic flux density generated by the magnet attached to the movable sheave, the system achieves direct position measurement with high precision without mechanical complexity

Inventive Principle:
Principle #35Parameter changes

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

Enables direct and accurate detection of the movable sheave's position within its displacement range, enhancing the accuracy and reliability of the continuously variable transmission device.

Implementation Method 1

a Hall IC sensor, integrated with a magnet, directly detects the magnetic flux density components in the x and z directions

Methodology Applied
Scientific EffectHall effect: Hall Effect

Data Source

PatentEP3358291B1Continuously variable transmission device
Publication Date: 2021.07.14 MELEXIS TECHNOLOGIES SA
  • EP3358291B1 patent drawingFigure 1
  • EP3358291B1 patent drawingFigure 2
  • EP3358291B1 patent drawingFigure 3

AI summary

To provide a displacement detection device and a continuously variable transmission device that directly detect the position of the movable sheave. A displacement detection device includes a magnet 62 that forms a magnetic field, a movable sheave 21 that is rotated in a rotational direction and displaced in a direction perpendicular to the rotational direction and that is a measuring object having a concave portion 210 (or a protrusion) on the circumferential surface, and a sensor 60 disposed between the magnet 62 and the circumferential surface of the movable sheave 21 and detecting a change in magnetic flux density due to the displacement of the movable sheave 21 in the magnetic field formed by the magnet 62 and induced to the concave portion 210 (or the protrusion) .