Design method of stepped magnetic contact structure based on magnetic circuit closing and magnetic flux leakage

Abstract

The invention relates to a stepped magnetic contact structure design method based on magnetic circuit closing and magnetic flux leakage, and the method comprises the following steps: 1, dividing a magnetic contact surface of a fixed iron core and a movable iron core in an electromagnetic system into a central attraction surface and an external gap surface, and enabling the fixed iron core and the movable iron core to be separated from each other after the fixed iron core and the movable iron core are attracted; a preset air gap is formed between the external gap surface and the corresponding magnetic contact surface; secondly, the height of an air gap is set so that the air gap can meet the tolerance requirement of machining precision; according to the invention, the magnetic contact surface structure is partitioned according to functions and respectively bears double responsibilities of a suction surface for rapid closing and a clearance surface for energy slow release; an air gap structure is designed to induce magnetic flux edge leakage, part of magnetic force is still kept after attraction is achieved, kinetic energy generated by impact of a movable iron core is effectively matched and dissipated, a mathematical model of magnetic flux conservation and kinetic energy counteracting is constructed, backstepping calculation of facet structure parameters is achieved, and design scientificity and accuracy are ensured.

Description

Technical Field

[0001] The present application relates to the field of solenoid valve engineering technology, and in particular to a design method for a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage. Background Art

[0002] In electromagnetic systems such as solenoid valves, electromagnetic relays, and magnetic actuators, the common soft magnetic contact structure consists of a fixed iron core, a movable iron core, and an excitation coil. The contact process relies on the magnetic force generated by the magnetic field to quickly pull the movable iron core toward the fixed iron core, achieving mechanical closure. However, in practical applications, the contact structure after contact is often subject to the following problems: 1. Sudden change in magnetic resistance at the moment of attraction: Due to the high magnetic permeability of soft magnetic materials, the magnetic circuit closes quickly after the iron core contacts, and the magnetic resistance drops sharply, causing the external magnetic field to decay rapidly and the attraction magnetic force to approach zero; 2. The mechanical kinetic energy of the iron core is not effectively dissipated: the kinetic energy accumulated by the movable iron core during the accelerated opening movement cannot be dissipated, and eventually a reverse impact force is generated on the contact surface; 3. Rebound phenomenon causes flow disturbance: The backlash causes the iron core to temporarily separate from the fixed end, resulting in unstable magnetic force, fluctuation of valve body opening and even failure of operation. The impact is particularly serious in scenarios of high-frequency opening and closing or high-precision flow control applications.

[0003] Currently, in order to solve the above problems, the following two solutions are adopted in the prior art: 1. By adding a slot to the upper fixed core part (such as Figure 9 As shown in the figure, an annular groove structure is designed on one side of the fixed core to leave a partially open magnetic path during the attraction process, forming a residual magnetic flux. This residual magnetic field provides additional suction at the moment of core contact, counteracting the recoil force generated by the accumulated kinetic energy of the moving core, thereby reducing the degree of rebound. Under this design concept, if the slot occupies too large a volume, it will lead to uneven magnetic field distribution (the slot changes the distribution of the main magnetic circuit, which may affect the magnetic force of the main attraction surface and even cause local magnetic saturation or bias) and a decrease in the original attraction magnetic force. If the slot occupies a small volume, the rebound reduction effect is not obvious.

[0004] 2. Add an energy absorbing material in the middle of the suction surface (such as Figure 10(as shown), the soft material in the middle absorbs the impact force, thereby reducing rebound. However, to maintain the valve opening, the distance between the two engaging surfaces must be increased, which reduces the magnetic force and affects the valve opening process. The latter method offsets the disadvantage of the increased engagement distance by increasing the coil power. This can affect the valve's performance under repeated openings and high temperature environments, making it more likely to overheat and malfunction. Furthermore, elastic materials are prone to heat accumulation, deformation fatigue, and material aging under high-frequency engagement, resulting in low reliability.

[0005] Therefore, there is an urgent need for a structural design method that can achieve simultaneous magnetic force release and kinetic energy absorption during attraction from the perspective of magnetic circuit design, so as to ensure the attraction stability, response consistency and repeated action reliability of the electromagnetic system. Summary of the Invention

[0006] In order to solve the problems raised in the above background technology that the sudden change in magnetic resistance of the existing electromagnetic system at the moment of attraction causes a sudden drop in suction force, the kinetic energy of the active iron core cannot be effectively dissipated, and the rebound causes flow disturbance, the present application provides a design method of a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage.

[0007] The design method of the stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage provided in this application adopts the following technical solutions: The design method of a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage includes the following steps: Step 1: dividing the magnetic contact surface between the fixed iron core and the movable iron core in the electromagnetic system into a central attraction surface and an outer gap surface, wherein, after the fixed iron core and the movable iron core are attracted, a preset air gap is formed between the outer gap surface and the corresponding magnetic contact surface; Step 2: Set the air gap height , so that it meets the tolerance requirements of machining accuracy and considers the maximum value of air gap height under machining deviation To ensure that the work done on the gap surface is greater than the impact kinetic energy when the movable iron core is opened; Step 3: According to the movement distance of the movable iron core , open response time , Mass of movable core , magnetic field strength of the attraction surface at equal spacing , horizontal projection area of ​​contact surface , vacuum permeability , the impact kinetic energy generated by the impact of the movable iron core and the fixed iron core is calculated by the principle of conservation of energy, and the impact kinetic energy is obtained : ; And the kinetic energy of the external gap surface flux work is obtained : ; in, is the radius of the circular ring of the center suction surface; Step 4: Pass the command , the maximum radius of the central suction surface ring can be deduced ,Right now: ; The solution is : ; When the actual designed center suction surface ring radius When the magnetic force generated by the gap magnetic resistance is regulated, it can offset the impact kinetic energy generated by the active iron core during the attraction process, thus preventing rebound or collision.

[0008] By adopting the above technical solution, the central suction surface can be closed first after the excitation is started, ensuring that the suction action responds promptly and the suction force is quickly established; while the external gap surface and the opposite magnetic contact surface maintain a preset small air gap, and still maintain a certain magnetic resistance after the central surface contacts, forming a controllable "leakage magnetic zone" to absorb the mechanical kinetic energy of the end movement of the movable iron core to prevent it from rebounding or multiple collisions. By introducing a stepped partitioning design combining the central suction surface and the external gap surface, the limitation of the sudden drop in suction force when the magnetic circuit is closed in the traditional suction structure is broken, and a dynamic matching relationship between magnetic force release and impact kinetic energy absorption is achieved at the structural level; this design method establishes an energy conservation model based on parameters such as the iron core mass, motion displacement, magnetic field strength and suction time, matches the kinetic energy of the iron core end with the work done by the magnetic force of the outer ring gap, and then reversely deduces the design boundary of the outer ring area and gap structure, realizing quantitative structural design.

[0009] Optionally, in step 2, the air gap height The value of is: ; Maximum air gap height The value of is: ; in, For processing accuracy.

[0010] By adopting the above technical solution and accurately setting the gap height and its maximum value, the error tolerance under different processing accuracy levels is fully taken into account, ensuring the stability and consistency of the structure in actual manufacturing and assembly; specifically, the design rule ensures that the air gap height is neither too small, resulting in the inability to realize the process, nor too large, resulting in insufficient magnetic flux leakage, ensuring that the gap magnetic resistance can effectively participate in energy absorption regulation under actual working conditions, which is conducive to standardized production and modular design, while enhancing the structure's adaptability to various magnetic actuators, improving the stability and reliability of the entire system under different working conditions, and avoiding performance fluctuations due to manufacturing errors or environmental changes.

[0011] Optionally, the central attraction surface is a circular or polygonal contact area arranged at the axis of the fixed iron core and / or the movable iron core, which preferentially completes the magnetic circuit closure.

[0012] By adopting the above technical solution, the central attraction surface is designed as a circular or polygonal contact area set at the axis of the fixed iron core and / or the movable iron core, so that this area completes the magnetic circuit closure first, thereby guiding the main magnetic circuit of the entire system to be quickly established.

[0013] Optionally, the outer gap surface is arranged around the central suction surface.

[0014] By adopting the above technical solution, a symmetrical and stable magnetic contact structure can be formed, so that the magnetic flux leakage path is evenly distributed along the radial direction, which can further enhance the magnetic resistance slow release effect.

[0015] Optionally, the central attraction surface and the outer gap surface form a stepped structure at the end of the iron core.

[0016] By adopting the above technical solution, the ladder structure can realize multi-level distribution of the magnetic circuit without increasing the complexity of the additional structure, adjust the ratio of primary and secondary magnetic flux diversion, realize precise control of the magnetic attraction process, and reduce the recoil force generated when the movable iron core is attracted at high speed.

[0017] Optionally, in step 3, the horizontal projection area of ​​the contact surface , The maximum outer edge radius of the circular profile of the external clearance surface.

[0018] By adopting the above technical solution, it is possible to meet the computational modeling requirements of various complex contact interfaces, enhance the versatility and engineering adaptability of the design method, and be suitable for rapid optimization and simulation calculations under different core structure conditions.

[0019] Optionally, the structures of the central suction surface and the external gap surface are planes, arc surfaces or inclined surfaces.

[0020] By adopting the above technical solution, the method can have higher geometric freedom and engineering adjustability. By adopting different structures, the interface design and energy absorption strategy can be flexibly matched according to the different requirements of specific products for suction distribution, cushioning performance and manufacturing cost.

[0021] Optionally, the design method is applicable to fields including but not limited to micro solenoid valves, hydraulic servo valves, and magnetic control relays.

[0022] By adopting the above technical solution, the design method has good versatility and extensibility. Through the systematic modeling and analysis of the magnetic flux leakage and energy matching principle of the magnetic contact structure, customized design of the attraction structure in different sizes and working environments can be realized, which has the advantage of a wide range of applications.

[0023] In summary, this application includes at least one of the following beneficial technical effects:

[0024] The present invention divides the magnetic contact surface structure into functional areas, which respectively assume the dual duties of the "quick closure" attraction surface and the "energy slow release" gap surface; by designing the air gap structure to induce the edge leakage of magnetic flux, it is achieved that part of the magnetic force is still maintained after attraction, effectively matching and dissipating the kinetic energy generated by the impact of the active iron core, constructing a mathematical model of "magnetic flux conservation + kinetic energy compensation", realizing the reverse calculation of the facet structure parameters, and ensuring the scientificity and accuracy of the design.

[0025] The present invention adopts a method for calculating the horizontal projected area, supports various forms of contact interfaces such as planes, curved surfaces and inclined surfaces, and has a high degree of engineering adaptability and modular design capabilities. This structure not only significantly reduces the impact of the rebound of the movable iron core on the system performance and reduces the dependence on additional buffering mechanisms, but also has the advantages of simple structure, fast response and strong adaptability. It is particularly suitable for various high-frequency and high-response electromagnetic attraction systems such as micro solenoid valves, hydraulic servo valves, and magnetic control relays. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a three-dimensional structural diagram of embodiment 1 of the present invention;

[0027] Figure 2 is a partial cross-sectional view of embodiment 1 of the present invention;

[0028] Figure 3 is a partial enlarged view of the first embodiment of the present invention;

[0029] Figure 4 is a top view of the stepped structure of the first embodiment of the present invention;

[0030] Figure 5 is a cross-sectional view of a second embodiment of the present invention;

[0031] Figure 6 is a cross-sectional view of a third embodiment of the present invention;

[0032] Figure 7 is a cross-sectional view of a fourth embodiment of the present invention;

[0033] Figure 8 is a cross-sectional view of embodiment 5 of the present invention

[0034] Figure 9 It is a structural diagram of a solution in the prior art;

[0035] Figure 10 It is a structural diagram of another solution in the prior art.

[0036] Description of reference numerals:

[0037] 1. Fixed iron core; 2. Movable iron core; 3. Center suction surface; 4. External gap surface; 5. Air gap; 6. Slot hole; 7. Energy-absorbing material. DETAILED DESCRIPTION

[0038] The present application is further described in detail below with reference to the accompanying drawings.

[0039] Example 1

[0040] like Figure 1-4 As shown, the embodiment of the present application discloses a design method for a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage. The design method is applicable to fields including but not limited to micro solenoid valves, hydraulic servo valves, and magnetic control relays, and specifically includes the following steps: Step 1: Divide the magnetic contact surface of the fixed iron core 1 and the movable iron core 2 in the electromagnetic system into a central attraction surface 3 and an external gap surface 4. The external gap surface 4 is arranged around the central attraction surface 3. The central attraction surface 3 and the external gap surface 4 form a stepped structure at the end of the iron core. After the fixed iron core 1 and the movable iron core 2 are attracted, a preset air gap 5 is formed between the external gap surface 4 and the corresponding magnetic contact surface. In this example, the central attraction surface 3 is a circular or polygonal contact area provided at the axis of the movable iron core 2, which preferentially completes the magnetic circuit closure. The structure of the central attraction surface 3 and the external gap surface 4 is a planar structure. Step 2: Set the height of air gap 5 , so that it meets the tolerance requirements of machining accuracy and considers the maximum value of the air gap 5 height under machining deviation To ensure that the work done by the gap surface is greater than the impact kinetic energy when the movable iron core 2 is opened; the height of the air gap 5 The value of is: ; Maximum height of air gap 5 The value of is: ; in, For machining accuracy; Step 3: According to the movement distance of the movable iron core 2 , open response time , Mass of movable core 2 , magnetic field strength of the attraction surface at equal spacing , horizontal projection area of ​​contact surface (Horizontal projection area of ​​contact surface , External gap surface 4 Maximum outer edge radius of the circular contour), vacuum permeability , calculate the impact kinetic energy generated when the movable iron core 2 impacts the fixed iron core 1 by the principle of conservation of energy, and obtain the impact kinetic energy : ; And the kinetic energy of the magnetic flux work done on the external gap surface 4 is obtained : ; in, is the radius of the circular ring of the center suction surface 3; Step 4: Pass the command , the maximum radius of the three circular rings of the center suction surface can be deduced ,Right now: ; The solution is : ; When the actual designed center suction surface 3 ring radius When the magnetic force generated by the gap magnetic resistance is 1 / 4, it can be ensured that the magnetic force generated by the gap magnetic resistance can offset the impact kinetic energy generated by the movable iron core 2 during the attraction process, thereby preventing rebound or collision.

[0041] Specifically, in this embodiment, the known conditions are as follows: Movement distance of movable iron core 2 ; Open response time ; Mass of movable core 2 ; Magnetic field strength of the attraction surface at equal spacing ; Horizontal projection area of ​​the contact surface (The contact surface is projected as a circular surface with a diameter of 10 mm); Vacuum permeability [H / m]; Processing accuracy ; According to the description of the above formula, we can get ; The maximum radius of the three circular rings on the central suction surface can be obtained as follows:

[0042] That is, when the air gap 5 is designed to be 0.1 mm, the radius of the circular ring of the central suction surface 3 must be less than or equal to 4.52 mm to ensure that the gap surface can function to offset the impact kinetic energy.

[0043] Specifically, in other embodiments, the central suction surface 3 is a circular or polygonal contact area (such as Figure 5 As shown); it can be understood that the center suction surface 3 can also be provided at the fixed core 1 and the movable core 2 at the axis of the circular or polygonal contact area (such as Figure 6 shown).

[0044] Specifically, in other embodiments, by adopting the calculation method of the horizontal projection area, the structure of the central suction surface 3 and the external gap surface 4 is an arc surface (such as Figure 8 as shown) or an inclined plane (as Figure 7 As shown), it has high engineering adaptability and modular design capabilities.

[0045] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A design method for a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage, characterized in that: The following steps are involved: Step 1: dividing the magnetic contact surface of the fixed iron core (1) and the movable iron core (2) in the electromagnetic system into a central attraction surface (3) and an external gap surface (4), wherein, after the fixed iron core (1) and the movable iron core (2) are attracted, a preset air gap (5) is formed between the external gap surface (4) and the corresponding magnetic contact surface; Step 2: Set the height of the air gap (5) , so that it meets the tolerance requirements of machining accuracy and considers the maximum height of the air gap (5) under machining deviation To ensure that the work done by the gap surface is greater than the impact kinetic energy when the movable iron core (2) is opened; Step 3: According to the movement distance of the movable iron core (2) , open response time 、Mass of movable core (2) , magnetic field strength of the attraction surface at equal spacing , horizontal projection area of ​​contact surface , vacuum permeability , the impact kinetic energy generated by the impact of the movable iron core (2) and the fixed iron core (1) is calculated by the principle of conservation of energy, and the impact kinetic energy is obtained : ； And the kinetic energy of the magnetic flux work done on the external gap surface (4) is obtained : ； in, is the radius of the circular ring of the center suction surface (3); Step 4: Pass the command , the maximum radius of the central suction surface (3) can be deduced ,Right now The solution is : When the actual designed center suction surface (3) is the ring radius When the magnetic force generated by the gap magnetic resistance is ensured to offset the impact kinetic energy generated by the movable iron core (2) during the attraction process, thereby preventing rebound or collision.

2. The design method of a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage according to claim 1, characterized in that: In the step 2, the height of the air gap (5) The value of is: ； Maximum height of air gap (5) The value of is: ； in, For processing accuracy.

3. The design method of a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage according to claim 1, characterized in that: The central attraction surface (3) is a circular or polygonal contact area provided at the axis of the fixed iron core (1) and / or the movable iron core (2), which preferentially completes the closure of the magnetic circuit.

4. The design method of a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage according to claim 1, characterized in that: The outer gap surface (4) is arranged around the central suction surface (3).

5. The design method of a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage according to claim 1, characterized in that: The central suction surface (3) and the external gap surface (4) form a stepped structure at the end of the iron core.

6. The design method of a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage according to claim 1, characterized in that: In step 3, the horizontal projection area of ​​the contact surface =π·R o ᵤ t ², R o ᵤ t The maximum outer radius of the circular profile of the external clearance surface (4).

7. The design method of a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage according to claim 1, characterized in that: The structures of the central suction surface (3) and the external gap surface (4) are a plane, a curved surface or an inclined surface.

8. The design method of a stepped magnetic contact structure based on magnetic circuit closure and magnetic flux leakage according to claim 1, characterized in that: This design method is applicable to fields including but not limited to micro solenoid valves, hydraulic servo valves, and magnetic control relays.

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