Cylinder Position Sensor Magnet Segmentation

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Solution Overview

Problem

Existing cylinder designs with integrated position sensors are costly to produce, complex, and prone to magnetic interference, making them difficult to maintain and affecting surrounding sensors.

Innovation Solution

A cylinder design where the sensor magnet is attached to the cylinder rod and fixed relative to the cylinder housing, allowing rotation, with a small, circular segment-shaped magnet that only covers a fraction of the cylinder rod's circumference, minimizing production costs and magnetic interference.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a magnetic ring with part magnets is arranged on the piston, then the cylinder rod position can be detected, but the production cost increases significantly

Engineering Contradiction:

Improvecylinder rod position detectionVSAvoidproduction cost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The magnetic ring is divided into multiple part magnets arranged on the piston, each detecting a specific angular position. This segmentation allows position detection without requiring a complete magnetic ring, reducing material costs and simplifying manufacturing while maintaining measurement precision for cylinder rod position detection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of using a full magnetic ring around the entire piston circumference, only partial magnets are installed at critical angular positions. This partial action provides sufficient position information for the cylinder rod detection while significantly reducing the quantity of magnetic material and assembly complexity, thereby lowering production costs.

Inventive Principle:

Principle #16Partial or excessive action

2Measurement precision

If a position detection device is integrated into the fluidic cylinder, then the piston position can be detected, but the cylinder becomes complicated to produce and maintain

Engineering Contradiction:

Improvepiston position detectionVSAvoidcylinder construction complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The position detection function is merged with the existing piston structure by integrating part magnets directly onto the piston body. This combines the piston's mechanical function with the sensor target function, eliminating the need for separate position detection devices and reducing overall system complexity while maintaining detection precision.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The piston serves dual functions: it acts as both the actuating component and the carrier for position detection magnets. This multi-functionality reduces the number of separate components needed in the system, simplifying both production and maintenance while preserving accurate piston position measurement capabilities.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Force

If a large sensor magnet is used, then the magnetic field strength is sufficient, but surrounding sensors are influenced and measuring accuracy decreases

Engineering Contradiction:

Improvemagnetic field strengthVSAvoidmagnetic interference with surrounding sensors

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The sensor magnet is designed with non-uniform distribution of magnetic material, concentrating magnetic flux density in the local region where the sensor element is positioned. This local quality enhancement provides sufficient magnetic field strength for accurate detection while limiting the spatial extent of the magnetic field, thereby reducing interference with surrounding sensors and improving measurement accuracy.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The magnet geometry is optimized by varying parameters such as arc angle, radial thickness, and axial height to concentrate magnetic flux where needed. By adjusting these parameters, the magnetic field strength at the sensor position is maximized while the field's spatial spread is minimized, reducing harmful interference effects on nearby sensors and enhancing measuring accuracy.

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

The design simplifies production and maintenance, reduces magnetic interference, and enhances measuring accuracy by confining the magnetic field close to the sensor element, thus minimizing disruptions to nearby sensors.

Implementation Method 1

a position sensor that comprises a sensor magnet and a sensor element that interacts with the sensor magnet, the sensor magnet being configured to detect a cylinder-rod position relative to the cylinder housing

Methodology Applied

Scientific EffectMagnetic field interaction: Magnetic Field

Data Source

PatentUS8833234B2Cylinder

Publication Date: 2014.09.16 ZF CV SYST EURO BV

AI summary

A cylinder includes a piston moving in a cylinder housing fastened to a cylinder rod and rotatable about a cylinder longitudinal axis, and a position sensor comprising a sensor magnet and a sensor element, which interacts with the sensor magnet and which is configured to detect a cylinder rod position relative to the cylinder housing. The sensor magnet is fastened on the cylinder rod rotatably with respect to the cylinder rod and is guided non-rotatably with respect to the cylinder housing.