Adjustable Magnetic Target for Proximity Switches
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Solution Overview
Problem
Radially-magnetized SmCo magnets are expensive and difficult to manufacture, while traditional magnets have weak flux fields that are undetectable through barriers, and axially-magnetized SmCo magnets are unsuitable for applications requiring large distances between the sensor and target due to non-uniform flux fields.
Innovation Solution
An adjustable magnetic target assembly using axially-magnetized SmCo or neodymium magnets, where a stationary magnet and a movable magnet interact to simulate a radially-magnetized flux field, allowing for longitudinal displacement and rotation to extend the magnetic flux field detection range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If radially-magnetized SmCo magnets are used, then flux field strength and uniformity are improved, but manufacturing cost and difficulty increase
Solution Approach 1:
The patent divides a single radially-magnetized magnet into multiple axially-magnetized magnet segments arranged in an array. Each segment produces a magnetic flux field component, and the combined effect of multiple segments creates a flux field that approximates the radial magnetization pattern, achieving both strength and uniformity without the manufacturing complexity of radial magnetization
Solution Approach 2:
The patent uses an array of axially-magnetized magnet segments (composite structure) to replicate the magnetic field characteristics of a radially-magnetized magnet. By combining multiple simpler magnet elements, the system achieves the desired flux field properties through composite arrangement rather than complex single-magnet manufacturing
2Ease of manufacture
If traditional magnets are used, then manufacturing cost decreases, but flux field strength becomes too weak to be detected through barriers
Solution Approach 1:
The patent combines multiple axially-magnetized magnet segments into an array configuration. Individually, each segment uses inexpensive axially-magnetized magnets, but when combined, their magnetic flux fields add up to create a strong, detectable field that can penetrate barriers, thus achieving both low cost and high strength
3Ease of manufacture
If axially-magnetized SmCo magnets are used, then manufacturing cost decreases, but detection distance is reduced due to non-uniform flux fields
Solution Approach 1:
The patent transitions from a single-magnet configuration to a multi-segment array configuration, adding spatial dimensionality to the magnetic field generation. This array arrangement extends the detection range by distributing magnetic flux field sources across multiple positions, creating a more uniform and extended detection zone that maintains affordability
4Stability of the object's composition
If radially-magnetized magnets are used, then flux field uniformity is improved, but device complexity increases
Solution Approach 1:
The patent segments the magnetic field generation function across multiple axially-magnetized elements rather than requiring a single complex radially-magnetized element. This segmentation achieves flux field uniformity through the collective effect of multiple simple, identical segments, reducing the complexity of individual components while maintaining overall field 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
This solution provides a cost-effective and easy-to-manufacture alternative to radially-magnetized SmCo magnets, maintaining flux field strength and uniformity, enabling detection over larger distances and accommodating rotating targets.
Implementation Method 1
A top surface of the movable magnet is arranged to engage the contact surface of the adjusting member such that a longitudinal displacement of the adjusting member towards the distal end of the body tube displaces the movable magnet towards the stationary magnet. This displacement causes a magnetic flux field of the stationary magnet to extend away from a longitudinal axis of the stationary magnet and a magnetic flux field of the movable magnet to extend away from a longitudinal axis of the movable magnet.
Implementation Method 2
A magnetically-triggered proximity switch having a sensor at a proximate end of the switch is also included, and the sensor of the magnetically-triggered proximity switch is adapted to detect the magnetic flux field of the stationary magnet or the magnetic flux field of the movable magnet.
Data Source
Figure 1
Figure 2
Figure 3a~3d
AI summary
A magnetic target (22) is provided for use with a magnetic proximity switch. The magnetic target includes a cylindrical body tube (24) having an open end that partially defines a bore. A stationary magnet (28) is located within the bore opposite the open end, and a movable magnet (30) is disposed within the bore between the stationary magnet and the open end. An adjusting member (26) is received into the bore, and a contact surface of the adjusting member engages the movable magnet (30). When the adjusting member (26) is axially displaced, the contact surface causes a corresponding displacement of the movable magnet (30) relative to the stationary magnet (28), eventually causing the magnetic flux field of each magnet to expand in a radial direction away from the longitudinal axis of each magnet. The stationary magnet and the movable magnet may be either axially-magnetized samarium-cobalt magnets or axially- magnetized neodymium magnets.