Hydraulic Cylinder Piston Magnet Layout for Uniform Circumferential Sensing
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Solution Overview
Problem
Existing fluid pressure cylinders face challenges in producing a magnetic field around the entire circumference of a piston without using a ring-shaped magnet, requiring size adjustments of magnets based on cylinder diameter and lacking uniformity in magnetic flux density.
Innovation Solution
A piston unit with multiple magnets disposed at intervals in the circumferential direction, flanked by ring-shaped yokes, which increases magnetic flux density and allows for a uniform magnetic field around the entire circumference without the need for a ring-shaped magnet, enabling the use of common magnets across different cylinder diameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a ring-shaped magnet is used to produce a magnetic field around the entire circumference, then the magnetic field coverage is improved, but the magnet size must be changed depending on cylinder diameter and the structure becomes more complex
Solution Approach 1:
The patent divides the ring-shaped magnet into multiple separate magnets arranged circumferentially. Each magnet is a simple block shape that can be independently manufactured and positioned. The magnets are spaced apart and guided by magnetic flux through yokes, creating a segmented structure that achieves full circumferential coverage without requiring a single complex ring-shaped magnet.
2Adaptability or versatility
If magnets are disposed only at certain points in the circumferential direction, then the magnet size can be standardized, but a magnetic field cannot be produced around the entire circumference
Solution Approach 1:
The patent introduces yokes as intermediary magnetic flux guides between the separately positioned magnets. The yokes conduct magnetic flux circumferentially around the piston, connecting the discrete magnet positions into a continuous magnetic field path. This allows standardized magnets to be positioned at specific intervals while still achieving complete circumferential magnetic field coverage through the flux-guiding function of the yokes.
3Manufacturing precision
If a ring-shaped magnet is used, then the magnetic field is uniform around the circumference, but the axial dimension of the piston unit increases
Solution Approach 1:
The patent redistributes the magnetic flux path from primarily axial (through a thick ring-shaped magnet) to include a significant circumferential component (through the yokes). The yokes extend circumferentially around the piston, allowing magnetic flux to travel around the circumference rather than only axially through the magnet thickness. This dimensional shift reduces the axial space required while maintaining flux uniformity through the circumferential flux path.
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 configuration enables the production of a magnetic field around the entire circumference of the piston unit, allowing for the use of common magnets across various cylinder diameters, reducing the axial dimension of the piston unit, and simplifying the assembly and structure while maintaining uniform magnetic flux density.
Implementation Method 1
a magnetic field can be produced around the entire circumference without using a ring-shaped magnet
Data Source
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AI summary
This piston unit (18) is provided with: a piston body (40); packing (42) mounted on an outer circumferential portion of the piston body (40); a holding member (44) having a plurality of magnet holding portions (58) that are arranged along a circumferential direction; a plurality of magnets (46) which are held at intervals in the circumferential direction; a first annular yoke (47) disposed on one side in an axial direction of the plurality of magnets (46); and a second annular yoke (48) disposed on the other side in the axial direction of the plurality of magnets (46).