Hall Sensor Piston Movement Detection in Central Lubrication Systems

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Solution Overview

Problem

Conventional central lubrication systems fail to accurately detect small movements of pistons due to large pressure variations and small piston diameters, limiting their ability to operate effectively with small movement lengths.

Innovation Solution

A movement monitor unit with a junction part made from weakly magnetizable material, equipped with a permanent magnet and a sensor to detect changes in the magnetic field caused by the piston's movement, processes signals and forwards them to a control unit, allowing for accurate detection of small piston movements even outside a pressurized space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a magnetic switch with hysteresis is used to detect piston movement, then the system can operate with magnetable or non-magnetable feeder bodies, but the detection accuracy is insufficient for small piston movements

Engineering Contradiction:

Improvecompatibility with magnetable and non-magnetable feeder bodiesVSAvoidpiston movement detection accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces the conventional magnetic switch with a Hall effect sensor that detects changes in magnetic field strength caused by piston movement. This substitution eliminates the hysteresis problem inherent in magnetic switches and enables accurate detection of small piston movements, while maintaining compatibility with both magnetable and non-magnetable feeder bodies through the use of a permanent magnet mounted on the piston.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the detection parameter from binary switch states with hysteresis to continuous magnetic field strength measurements. By monitoring the strength of the magnetic field generated by the permanent magnet on the piston, the system can detect small movements with high precision, transforming the detection mechanism from a coarse binary state to a fine-grained continuous measurement.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the movement monitor unit is placed inside the pressurized space to detect piston movement, then direct detection is possible, but the complexity of wiring and I/O inputs increases

Engineering Contradiction:

Improvedirect piston movement detectionVSAvoidwiring and I/O input complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the electronics part of the movement monitor unit from the pressurized space and places it outside. The Hall effect sensor and permanent magnet remain near the piston to detect movement, but the signal processing and control electronics are relocated to a safe environment, simplifying wiring and reducing I/O complexity while maintaining detection accuracy.

Inventive Principle:

Principle #2Taking out (Extraction)

3Measurement precision

If a permanent magnet is mounted on the piston to generate a magnetic field for detection, then small piston movements can be detected, but the system requires weakly magnetable material for the junction part

Engineering Contradiction:

Improvesmall piston movement detection capabilityVSAvoidmaterial selection constraints

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies local quality by specifying that the junction part should be made from weakly magnetable material in the specific location where the magnetic field detection occurs. This localized material requirement ensures that the magnetic field generated by the permanent magnet on the piston can be detected accurately without being distorted by strongly magnetable materials, while other parts of the system can use standard materials.

Inventive Principle:

Principle #3Local quality

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 precise detection of small piston movements, reducing the need for complex wiring and I/O inputs, and allows for series coupling of outputs, enhancing the system's operational efficiency and reliability.

Implementation Method 1

a sensor part which, in turn, comprises a permanent magnet in order to generate a magnetic field

Methodology Applied

Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the sensor is a Hall sensor

Methodology Applied

Scientific EffectHall effect: Hall Effect

Data Source

PatentUS8104582B2Arrangement in connection with central lubrication system

Publication Date: 2012.01.31 OSAKEYHTIO SKF

AI summary

The invention relates to an arrangement in connection with a central lubrication system. The arrangement includes a lubricant vessel, a pump unit, a control unit, pipe systems, a pressure monitor unit, at least one lubricant feeder provided with at least one piston which moves due to the influence of the pressure of a lubricant present in the pipe system/object to be lubricated, and a movement monitor unit to monitor the operation of the feeder. The movement monitor unit includes a sensor part mounted to a nipple manufactured from a weakly magnetable material. The nipple includes a permanent magnet to generate a magnetic field, and a sensor for detecting movement of the piston, and an electronics part which processes a signal received from the sensor and forwards this processed signal to the control unit.