Electromagnet Device With Auxiliary Magnetic Circuit For Latching Relays
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Solution Overview
Problem
Conventional electromagnet devices for latching type electromagnetic relays face challenges in providing a strong retention force for movable iron pieces with strong spring forces, making it difficult to maintain both returned and moved states effectively.
Innovation Solution
The electromagnet device incorporates a horizontal portion of a yoke near an iron core with a movable iron piece pivotably supported on its vertical portion, utilizing a combined magnetic force from a main and auxiliary magnetic circuit. The auxiliary magnetic circuit, featuring a permanent magnet and a magnetic resistance portion with a small cross-sectional area, enhances the retention force by effectively using the magnetic flux.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the iron core frame is made of a semi-hard magnetic material, then the device can retain the movable iron piece, but it cannot provide strong enough retention force for movable iron pieces with strong spring forces
Solution Approach 1:
The magnetic circuit is segmented into a main magnetic circuit (for actuation) and an auxiliary magnetic circuit (for retention). This segmentation allows each circuit to be optimized for its specific function: the main circuit provides the force to move the iron piece against strong spring forces, while the auxiliary circuit provides continuous retention force to maintain the moved state reliably.
Solution Approach 2:
The patent combines the main magnetic circuit and auxiliary magnetic circuit into a unified electromagnet device structure. The auxiliary magnetic circuit with permanent magnets is integrated alongside the main coil-based circuit, allowing both to work together to provide the required retention force for heavy-duty applications.
2Force
If a strong retention force is needed to retain the movable iron piece in a moved state, then the device can maintain position, but it becomes difficult to drive movable touch pieces with strong spring force
Solution Approach 1:
The magnetic circuit is divided into separate main and auxiliary circuits with distinct functions. The main circuit handles the high-force actuation task of driving the movable touch piece against strong spring forces, while the auxiliary circuit handles the retention task, allowing each to be optimized without compromising the other.
Solution Approach 2:
The system dynamically switches between actuation mode (main circuit active) and retention mode (auxiliary circuit active). During actuation, the main circuit provides variable magnetic force to overcome spring forces and move the iron piece. After movement, the auxiliary circuit maintains retention with appropriate force, allowing the system to adapt to different operational requirements.
3Force
If the auxiliary magnetic circuit uses a permanent magnet with large cross-sectional area, then retention force increases, but magnetic flux leakage increases
Solution Approach 1:
The auxiliary yoke is designed with non-uniform cross-sectional area, featuring a narrow-width portion at the connection to the vertical yoke and a wider base portion. This local variation in geometry concentrates the magnetic flux in the narrow region, increasing retention force at the critical interface while preventing excessive flux spread and leakage in other areas.
Solution Approach 2:
The patent changes the geometric parameters of the auxiliary yoke, specifically the cross-sectional area at different locations. By creating a narrow-width portion with smaller cross-sectional area, the magnetic flux density is increased locally to enhance retention force, while the overall flux leakage is controlled through this parameter optimization.
4Ease of manufacture
If the narrow-width portion of the auxiliary yoke is positioned far from the movable iron piece, then alignment is easier, but retention force decreases
Solution Approach 1:
The auxiliary yoke concentrates its magnetic flux-generating capability at the narrow-width portion, which is strategically positioned to be as close as possible to the movable iron piece. This local concentration of magnetic function compensates for the positioning constraint, ensuring maximum retention force is achieved at the critical interaction point.
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 allows for a strong retaining force that maintains the movable iron piece in a moved state, ensuring reliable operation with reduced magnetic flux leakage and improved alignment accuracy, thus overcoming the limitations of conventional devices.
Implementation Method 1
an auxiliary magnetic circuit formed to be in parallel with the main magnetic circuit. The auxiliary magnetic circuit comprises a permanent magnet arranged near the one end portion of the iron core
Implementation Method 2
The magnetic circuit is formed by applying a voltage to a coil wound around a periphery of the iron core
Implementation Method 3
a magnetic resistance portion where a magnetic flux of the permanent magnet is magnetically saturated
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
The present invention provides an electromagnet device (20) comprising of a horizontal portion (53) of a yoke (50) arranged near one end portion of an iron core (40), a movable iron piece (60) which pivotably supported on a leading end edge portion of a vertical portion (51) of the yoke (50), an end portion of the movable iron piece (60) adapted to be attracted to a magnetic pole portion (42) by a main magnetic circuit (M2), the magnetic pole portion (42) is arranged in the other end portion of the iron core (40). The main magnetic circuit (M2) is formed by applying a voltage to a coil (31) wound around a periphery of the iron core (40) and an auxiliary magnetic circuit (M1) formed in parallel with the main magnetic circuit (M2), the auxiliary circuit (M1) comprises a permanent magnet (21) is arranged near the one end portion of the iron core (40) and a magnetic resistance portion, in which a magnetic flux of the permanent magnet (21) is magnetically saturated.