Magnetic Proximity Sensor Assembly with Uniform Bore Sleeve
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Solution Overview
Problem
Existing magnetic proximity sensor assemblies face challenges in precise positioning of the switch assembly within the blind bore, making it difficult to achieve and detect from a quality control perspective, especially due to varying diameters.
Innovation Solution
A magnetic proximity sensor assembly with a uniform bore diameter and a sleeve that surrounds the primary magnet, allowing precise positioning and movement within a defined area, utilizing a center magnet and biasing magnet for internal magnetic bias, and optionally using a mu-metal sleeve for enhanced magnetic field control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a varying diameter blind bore is provided to create a shoulder for positioning the switch assembly, then the switch assembly can be positioned at the required position, but the manufacturing process becomes challenging and quality control detection becomes difficult
Solution Approach 1:
The positioning function is segmented from the blind bore itself. Instead of relying on the blind bore's varying diameter to provide positioning, a separate sleeve component is introduced that provides the positioning shoulder. This separates the functions: the blind bore provides containment while the sleeve provides precise positioning through its shouldered design.
Solution Approach 2:
The sleeve acts as an intermediary component between the blind bore and the switch assembly. It mediates the positioning function by providing a standardized shouldered interface that is easier to manufacture than a varying diameter blind bore, while still achieving the required positioning precision for the switch assembly.
2Ease of operation
If the primary magnet is allowed to move freely in the blind bore, then the magnetic assembly can respond to targets, but the movement cannot be confined to a controlled area
Solution Approach 1:
The sleeve provides localized constraints specifically for the primary magnet while leaving other parts of the magnetic assembly free to move. The shouldered design of the sleeve creates a defined movement zone for the primary magnet without restricting the overall operation of the magnetic assembly in response to targets.
3Device complexity
If no shielding is provided for the primary magnet, then the structure is simpler, but surrounding ferrous metals can interfere with the magnetic field
Solution Approach 1:
The sleeve serves as an intermediary shielding element between the primary magnet and the external environment. It provides magnetic field protection against surrounding ferrous metals while maintaining a relatively simple overall structure. The sleeve's material and positioning are optimized to provide necessary shielding without excessive complexity.
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
Ensures precise and reliable detection of targets within the sensing range by maintaining the primary magnet's movement within a controlled area, preventing interference from surrounding ferrous metals and optimizing sensing distance, while allowing easy verification of the sleeve's length and positioning.
Implementation Method 1
magnetic assembly moveable in the blind bore... primary magnet and a biasing magnet... When a target, such as a magnet or ferrous object, is within the sensing range of the magnetic proximity sensor assembly, the magnetic assembly moves in the blind bore from a magnetically biased position towards the target
Implementation Method 2
optionally using a mu-metal sleeve for enhanced magnetic field control... preventing interference from surrounding ferrous metals
Data Source
AI summary
A magnetic proximity sensor assembly 10. The magnetic proximity sensor assembly 10 comprises a switch assembly 12 received in a blind bore 14 of a body tube 16. The switch assembly 12 comprises a magnetic assembly 18 moveable in the blind bore 14. The switch assembly 12 comprises an operator 42 which extends from the magnetic assembly 18 and serves as a drive for a moving contact 44 positioned between a first contact 46 and a second contact 48. The magnetic assembly 18 comprises a primary magnet 20 and a biasing magnet 22. The switch assembly 12 comprises a center magnet 26 interposed between the primary magnet 20 and the biasing magnet 22. The blind bore 14 has a uniform bore diameter. The magnetic proximity sensor assembly 10 comprises a sleeve 28 in the blind bore 14 contacting the closed end 30 of the blind bore 14. The switch assembly 12 is seated on the sleeve 28 such that the primary magnet 20 of the magnetic assembly 18 is surrounded by the sleeve 28.