A winding core fixture for a large-sized magnetic core and a preparation method for the magnetic core

Abstract

The present invention provides a core winding fixture for large-sized cores and a method for manufacturing cores, which relates to the technical field of core manufacturing, and includes: designing and manufacturing a special core winding fixture according to the inner diameter size of the finished core. The core winding fixture includes a working part and a connecting part. The working part is an arc segment with an outer radius equal to the inner radius of the finished core, and the connecting part is an arc segment connecting both ends of the working part. The working part and the connecting part are connected end to end to form a closed loop; winding the soft magnetic alloy strip around the outside of the core winding fixture, and together with the core winding fixture, performing heat treatment, dipping paint, and baking and curing treatment to obtain a core blank; cutting off the arc segment of the working part in the core blank along the radial direction as a splicing segment, and splicing and fixedly connecting a plurality of splicing segments to obtain a large-sized finished core. The beneficial effect is that while meeting the preparation requirements of large-sized cores, it can solve the problem that the magnetic ring cannot be heat-treated due to the limitation of the size of conventional heat treatment furnaces and other equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic core manufacturing, and particularly to a winding jig for a large-size magnetic core and a preparation method for a magnetic core. Background Art

[0002] With the development of the petrochemical industry and the acceleration of the urbanization process, the scale of the underground pipeline network is rapidly expanding. Corrosion currents are likely to be generated in buried pipelines due to corrosion, posing a hidden danger to pipeline safety, and this problem is becoming increasingly prominent. How to effectively monitor the corrosion current in the pipeline in real time online has become the key to preventing pipeline current corrosion. For the monitoring of pipeline current, currently, the commonly used method is to measure on-site with a handheld instrument by manual labor, which requires a large amount of manpower and material resources, has the disadvantages of long time consumption, high cost, and inability to monitor the change of pipeline current in real time; to achieve real-time monitoring, traditional optical fiber sensors and other real-time monitoring methods can be used, but this kind of monitoring method usually has high production and maintenance costs because it requires the use of a variety of optical devices.

[0003] Currently, it is an economical and convenient monitoring method to use a ring-shaped monitoring device made of a soft magnetic material with excellent soft magnetic properties and sleeved outside the pipeline to monitor the pipeline current in real time. Because the amorphous nanocrystalline soft magnetic alloy strip has characteristics such as high magnetic permeability and extremely low remanence, a relatively high magnetic induction intensity can be excited at a very low current, which is convenient for monitoring the corrosion current using a signal detection probe, and has the characteristics of high detection sensitivity and accurate current monitoring, and has shown good application prospects in the application of pipeline corrosion current monitoring. In order to ensure the accuracy and stability of real-time monitoring, the preparation process of the amorphous nanocrystalline magnetic core sleeved outside the pipeline is usually: first, wind the amorphous nanocrystalline strip into an annular magnetic core blank according to the outer diameter of the pipeline, and then perform heat treatment, dipping paint, curing and other processes on the winding jig and the magnetic core blank together. After being shaped, it is used for pipeline current monitoring. However, when the amorphous nanocrystalline soft magnetic alloy strip is currently applied to a large-size or large-diameter pipeline current monitoring device, the following problems exist: the inner cavities of conventional heat treatment furnaces, dipping paint equipment, or curing equipment are relatively small and cannot accommodate large-size magnetic rings and their winding jigs, which hinders the application of amorphous nanocrystalline monitoring devices in the monitoring of large-diameter pipeline currents. For example, if a heat treatment furnace or other supporting equipment is redesigned and developed, the required cycle is too long, the cost is too high, and the utilization rate is low.

[0004] Therefore, it is urgent to develop a preparation method for a large-size magnetic core that can not only meet the large-size requirements of pipeline monitoring but also be applicable to existing heat treatment and supporting equipment. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a core winding fixture for large-sized cores and a method for preparing cores, which can not only meet the preparation requirements of large-sized cores, but also solve the problem that magnetic rings cannot be heat-treated due to the limitation of the size of conventional heat treatment furnaces and other equipment.

[0006] A core winding fixture for large-sized cores is designed and manufactured according to the inner diameter size of the finished core. The core winding fixture includes a working part and a connecting part. The working part is an arc segment with an outer radius equal to the inner radius of the finished core, and the connecting part is an arc segment connecting both ends of the working part. The working part and the connecting part are connected end to end to form a closed loop.

[0007] The arc angle of the working part is not less than 20°.

[0008] Preferably, the value range of the arc height a of the connecting part is: a≥5mm.

[0009] Preferably, the value range of the arc height h of the working part is:

[0010] 5mm≤h<A-a-2d,

[0011] wherein, A represents the minimum value of the inner cavity size of the heat treatment furnace, the inner cavity size of the dipping equipment, and the inner cavity size of the oven used in the preparation process of the core blank, and d represents the wall thickness of the finished core.

[0012] Preferably, the connection between the two arc segments of the working part and the connecting part is smoothly transitioned.

[0013] Preferably, at least one support rod is further included inside the core winding fixture. The support rod is arranged inside the closed loop formed by the connection of the working part and the connecting part, and both ends of the support rod are connected to the inner side of the closed loop.

[0014] Preferably, a collar is further included inside the core winding fixture. The collar is arranged on the support rod and is located at the central part of the support rod.

[0015] Preferably, there are two support rods, namely a first support rod and a second support rod. The first support rod and the second support rod intersect and are perpendicular to each other, and the collar is arranged at the intersection of the first support rod and the second support rod.

[0016] A method for preparing a large-sized core uses the above-mentioned core winding fixture to prepare a large-sized core, including the following steps:

[0017] S1. Wind the soft magnetic alloy strip around the outside of the core winding fixture, and perform heat treatment, dipping, and baking and curing treatments together with the core winding fixture to obtain a core blank;

[0018] S2. Cut off the arc segment of the working part in the magnetic core blank obtained in step S1 along the radial direction as the splicing segment of the magnetic core.

[0019] S3. Polish and flatten the cutting section of the splicing segment obtained in step S2, and splice and fixedly connect multiple splicing segments to obtain the finished magnetic core.

[0020] Preferably, in steps S2 and S3, the arc angle of the splicing segment is 360° / n, where n is a positive integer and the range of n is: 2 ≤ n ≤ 18.

[0021] Preferably, in step S3, the method of fixedly connecting the splicing segments is bonding and fixing with a soft magnetic adhesive or hinge connection and fixing.

[0022] The above technical solution has the following advantages or beneficial effects:

[0023] 1) Using a core jig composed of two arc segments to prepare a large-size magnetic core can not only meet the preparation requirements of the large-size magnetic core, but also solve the problem that the magnetic ring cannot be heat-treated due to the limitation of the size of conventional heat treatment furnaces and other equipment.

[0024] 2) Set the arc height of the connecting part and the working part according to the inner cavity size of the heat treatment furnace, the inner cavity size of the dipping equipment and the inner cavity size of the oven, and at the same time set a support rod inside, which can ensure uniform stress during the winding process of the magnetic ring and improve the reliability of the product.

[0025] 3) The structure of the core jig is simple, the processing is convenient, the development cycle is short, and the production cost can be greatly saved. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic structural diagram of the core jig for a large-size magnetic core in Embodiment 1 of the present invention;

[0027] Figure 2 It is a schematic structural diagram of a winding strip on the core jig in Embodiment 1 of the present invention;

[0028] Figure 3 It is a schematic structural diagram of the splicing segment in Embodiment 1 of the present invention;

[0029] Figure 4 It is a schematic structural diagram of the finished magnetic core after splicing in Embodiment 1 of the present invention;

[0030] Figure 5 It is a schematic flow chart of the method for preparing a large-size magnetic core in Embodiment 1 of the present invention;

[0031] Figure 6Schematic structural diagram of the core winding fixture for large-sized cores in Embodiment 2 of the present invention;

[0032] Figure 7 Schematic structural diagram of the strip winding on the core winding fixture in Embodiment 2 of the present invention;

[0033] Figure 8 Schematic structural diagram of the splicing section in Embodiment 2 of the present invention;

[0034] Figure 9 Schematic structural diagram of the finished core product after splicing in Embodiment 2 of the present invention.

[0035] In the drawings: 1, working part; 2, connecting part; 3, first support rod; 4, second support rod; 5, collar; 6, strip; 7, splicing section; 8, finished core product. Detailed implementation manners

[0036] The present invention will be described in detail below with reference to the drawings and specific embodiments. The present invention is not limited to this embodiment, and other embodiments can also fall within the scope of the present invention as long as they conform to the gist of the present invention.

[0037] In a preferred embodiment of the present invention, in view of the above problems existing in the prior art, a core winding fixture for large-sized cores is provided. As shown in Figure 1 and Figure 4 , a special core winding fixture is designed and manufactured according to the inner diameter size of the finished core product 8. The core winding fixture includes a working part 1 and a connecting part 2. The working part 1 is an arc segment with an outer radius r equal to the inner radius of the finished core product 8, and the connecting part 2 is an arc segment connecting the two ends of the working part 1. The working part 1 and the connecting part 2 are connected end to end to form a closed loop.

[0038] In a preferred embodiment of the present invention, the arc angle of the working part 1 is not less than 20°.

[0039] In a preferred embodiment of the present invention, the value range of the arc height a of the connecting part 2 is: a ≥ 5 mm.

[0040] In a preferred embodiment of the present invention, the value range of the arc height h of the working part 1 is: 5 mm ≤ h < A - a - 2d,

[0041] where A represents the minimum value among the inner cavity size of the heat treatment furnace used in the process of preparing the core blank, the inner cavity size of the dipping equipment used, and the inner cavity size of the oven used, and d represents the wall thickness of the finished core product 8.

[0042] By corresponding to a core fixture composed of two arc segments, it is possible to prepare the required large-size annular magnetic core under the limitations of the inner cavity sizes of the existing heat treatment furnace, dipping equipment, and oven, achieving both the preparation requirements for large-size magnetic cores and solving the problem that magnetic rings cannot be heat-treated due to the limitations of the size of conventional heat treatment furnaces. There is no need to redesign and develop equipment such as heat treatment furnaces, and the structure of the core fixture is simple, the processing is convenient, the development cycle is short, and the production cost can be greatly saved.

[0043] Example 1

[0044] In this example, as Figures 1 to 4 shown, the core fixture includes a semi-circular core and an arc-shaped core connected correspondingly. Among them, the semi-circular core is the working part 1, and its outer radius r1' is equal to the inner diameter r1 of the magnetic core finished product 8. The arc-shaped core is the connecting part 2, and its outer radius is reasonably set according to the minimum value among the inner cavity sizes of the heat treatment furnace, dipping equipment, and oven.

[0045] Further specifically, when preparing a large-size annular magnetic core, the soft magnetic alloy material is wound around the outer periphery of the core fixture to form a primary magnetic ring and then put into the heat treatment furnace for heat treatment. Subsequently, after the magnetic ring is cured, it is taken out from the core fixture. At this time, the taken-out primary magnetic ring is adapted to the shape of the core fixture. Considering that the large-size annular magnetic core prepared by this technical solution is applied to scenarios such as pipeline monitoring that require large-size magnetic cores and needs to be adapted to the inner diameter of the pipeline, which is usually a relatively regular circle. After taking out the primary magnetic ring from the core fixture, as Figure 3 shown, it is preferably cut at least once along the connection between the semi-circular core and the arc-shaped core to obtain a semi-circular magnetic core for retention, and then another semi-circular magnetic core for retention is prepared based on the core fixture. Subsequently, the two semi-circular magnetic cores are assembled and fixed. As Figure 4 shown, the position pointed by the black arrow is the connection part of the two semi-circular magnetic cores, and a large-size annular magnetic core can be obtained. If a larger-size annular magnetic core needs to be prepared, the arc segment (working part 1) of the core fixture can be re-set according to the size of the required magnetic core, and the above preparation process is repeated. The multiple arc-shaped magnetic cores obtained by cutting can be assembled and fixed to obtain a large-size annular magnetic core that meets the required size.

[0046] In summary, it can be seen that when designing the size of the core jig, in order to enable the primary magnetic ring to be placed in equipment such as a heat treatment furnace, the arc height h of the working portion 1 is jointly determined by the radius of the primary magnetic ring and the minimum value A among the inner cavity sizes of the heat treatment furnace, the dipping equipment, and the oven. It can be seen that the arc height h of the accommodable working portion 1 is less than A - a - 2d, where A is used to represent the minimum value among the inner cavity sizes of the heat treatment furnace, the dipping equipment, and the oven used in the preparation process of the magnetic core blank, a is used to represent the arc height of the connecting portion 2 of the core jig, that is, the arc height of the circular arc-shaped core, and d is used to represent the wall thickness of the magnetic core finished product 8. Since the circular arc-shaped magnetic core adapted to the shape of the connecting portion 2 is not used after preparation, in order to avoid material waste as much as possible, ideally, the arc height of the connecting portion 2 should be as small as possible. At the same time, considering the stability of the core jig during the preparation process, the arc height of the connecting portion 2 cannot be too small. In this embodiment, the value range of the arc height of the connecting portion 2 is set as: a ≥ 5 mm, and the value range of the arc height of the working portion 1 is: 5 mm ≤ h < A - a - 2d. It should be noted that by adjusting the appropriate arc heights of the working portion 1 and the connecting portion 2 according to the inner cavity sizes of equipment such as the heat treatment furnace and the preset size of the magnetic core, the force on the finally obtained core jig in all directions can be made more uniform, the consistency of the wound magnetic core is better, and the performance reliability is higher.

[0047] In a preferred embodiment of the present invention, the connection between the two arc segments of the working portion 1 and the connecting portion 2 is smoothly transitioned.

[0048] Specifically, in this embodiment, at the two connections between the working portion 1 and the connecting portion 2, a small-sized arc can be respectively provided to make the connection tend to be gentle, so that the strip 6 can be smoothly spread on the surface of the core during the winding process.

[0049] In a preferred embodiment of the present invention, the core jig further includes at least one support rod, the support rod is disposed inside a closed loop formed by the corresponding connection of the working portion 1 and the connecting portion 2, both ends of the support rod are connected to the inner side of the closed loop, and the collar 5 is disposed on the support rod and is located at the central portion of the support rod;

[0050] The length of the support rod is not greater than the size of the working portion 1, and the size of the collar 5 is adapted to the inner lining of the winding machine used for winding the soft magnetic alloy material.

[0051] Specifically, in this embodiment, the shape and size of the collar 5 are adapted to the inner lining of the winding machine, so as to realize the winding function of the core. In addition, the collar 5 is disposed at the position of the center of the working portion 1, which can ensure the smooth rotation of the core during the winding process. In this embodiment, the shape of the collar 5 is square, and in practical applications, the collar 5 with a corresponding shape can be set according to the shape of the inner lining of the winding machine.

[0052] In a preferred embodiment of the present invention, there are two support rods, namely a first support rod 3 and a second support rod 4. The first support rod 3 and the second support rod 4 intersect and are perpendicular to each other. The collar 5 is arranged at the intersection of the first support rod 3 and the second support rod 4.

[0053] Specifically, in this embodiment, the first support rod 3 is arranged along the linear direction of the size of the working part 1. Both the first support rod 3 and the second support rod 4 pass through the center of the working part 1. And both ends of the first support rod 3 are respectively connected to the two connection points of the working part 1 and the connection part 2, which can play a supporting role and at the same time reinforce the connection points of the two structures. Cooperating with the second support rod 4 which is perpendicularly arranged thereto, it can enhance the stability of the entire core structure and at the same time solve the problem of uneven stress on the core.

[0054] A method for preparing a large-sized magnetic core, as Figures 2 to 5 shown, uses the above-mentioned core jig to prepare a large-sized magnetic core, including the following steps:

[0055] S1. Wind the soft magnetic alloy strip 6 around the outside of the core jig, and perform heat treatment, dip painting, and baking and curing treatment together with the core jig to obtain a magnetic core blank;

[0056] S2. Cut off the arc section of the working part 1 of the magnetic core blank obtained in step S1 along the radial direction as the splicing section 7 of the magnetic core;

[0057] S3. Polish and level the cutting section of the splicing section 7 obtained in step S2, and splice and fixedly connect multiple splicing sections 7 to obtain the finished magnetic core 8.

[0058] In a preferred embodiment of the present invention, in step S1, vacuum heat treatment furnace is used for heat treatment, the heat treatment temperature is 230°C - 600°C, and the heat preservation time is 0.5 - 5h.

[0059] In a preferred embodiment of the present invention, the dip painting and baking and curing in step S1 are specifically to use a vacuum dip painting device to perform dip painting treatment on the core, so that the liquid resin penetrates into the internal voids of the core, and the core after dip painting treatment is baked and cured by a vacuum oven.

[0060] Among them, the baking temperature is 100°C - 220°C, and the heat preservation time is 0.5 - 6h.

[0061] In a preferred embodiment of the present invention, the cutting method in step S2 can be carried out by using a grinding wheel or a diamond saw blade.

[0062] In a preferred embodiment of the present invention, after cutting, it also includes a surface loss reduction treatment process and a surface protection treatment process.

[0063] Specifically, the method for reducing surface damage of the bobbin fixture is to soak it in a weakly acidic solution, and the method for surface protection treatment of the bobbin fixture is to evenly coat it with a self-drying insulating paint.

[0064] In a preferred embodiment of the present invention, in steps S2 and S3, the arc angle of the splicing segment 7 is 360° / n, where n is a positive integer, and the range of n is: 2 ≤ n ≤ 18.

[0065] In a preferred embodiment of the present invention, in step S3, the method for fixedly connecting the splicing segment 7 is bonding and fixing with a soft magnetic adhesive or hinge connection and fixing.

[0066] Embodiment 2

[0067] In this embodiment, as Figures 6 - 9 shown, the working part 1 of the bobbin fixture is a quarter arc segment, that is, the arc angle of the working part is 90°, and its outer radius is equal to the inner radius of the magnetic core finished product 8. The connecting part 2 is an arc segment connected to the head and tail of the working part 1.

[0068] Specifically, in this embodiment, the inner radius of the magnetic core finished product 8 is greater than the inner radius r1 of the magnetic core finished product 8 in Embodiment 1. If a bobbin fixture composed of a semi-circular bobbin and a circular arc bobbin in Embodiment 1 is used, the size of the wound magnetic ring will exceed the inner cavity size of equipment such as a heat treatment furnace. Therefore, in this embodiment, the magnetic core finished product 8 is designed to be composed of the arc splicing of 4 splicing segments 7, and the arc angle of the splicing segment 7 is 90°, as Figure 9 shown, the position pointed by the black arrow is the connection part of the 4 splicing segments 7.

[0069] More specifically, the arc angle of the splicing segment 7 is 360° / n, where n is a positive integer, which can represent the number of splicing segments 7 that make up the magnetic core finished product 8. The range of n is: 2 ≤ n ≤ 18. The larger the inner radius r of the required magnetic core finished product 8, the larger the value of n. If the number of required splicing segments 7 is too large, it will cause an increase in production costs. Therefore, the range of n is limited to: 2 ≤ n ≤ 18.

[0070] The above are only preferred embodiments of the present invention, and thus do not limit the implementation manners and protection scope of the present invention. For those skilled in the art, it should be able to realize that all equivalent replacements and obvious changes made by using the content of this specification and the drawings should be included in the protection scope of the present invention.

Claims

1. A winding core fixture for a large-sized magnetic core, characterized in that, The core fixture includes a working part and a connecting part. The working part is an arc segment with an outer radius equal to the inner radius of the magnetic core finished product. The connecting part is an arc segment connecting the two ends of the working part. The working part and the connecting part are connected end to end to form a closed loop. The arc angle of the working part is not less than 20°. The value range of the arc height a of the connecting part is: a≥5mm. The value range of the arc height h of the working part is: 5mm≤h<A-a-2d, and the arc height a of the connecting part is not equal to the arc height h of the working part. Among them, A is used to represent the minimum value among the inner cavity size of the heat treatment furnace used in the preparation process of the magnetic core, the inner cavity size of the dipping equipment used, and the inner cavity size of the oven used. d is used to represent the wall thickness of the magnetic core finished product.

2. The core jig according to claim 1, characterized in that, The connection between the two arc segments of the working part and the connecting part is smoothly transitioned.

3. The core jig according to claim 1, wherein The core fixture further includes at least one support rod inside. The support rod is arranged inside the closed loop formed by the connection of the working part and the connecting part, and both ends of the support rod are connected to the inner side of the closed loop.

4. The core jig according to claim 3, wherein, The core fixture further includes a collar inside. The collar is arranged on the support rod and is located at the central part of the support rod.

5. The core jig according to claim 4, wherein, There are two support rods, namely a first support rod and a second support rod. The first support rod and the second support rod intersect and are perpendicular to each other. The collar is arranged at the intersection of the first support rod and the second support rod.

6. A method for preparing a large-sized magnetic core, characterized in that, Using the core fixture according to any one of claims 1 to 5 to prepare a large-sized magnetic core, includes the following steps: S1. Wind the soft magnetic alloy strip outside the core fixture, and perform heat treatment, dipping, and baking and curing treatments together with the core fixture to obtain a magnetic core blank. S2. Cut off the arc segment of the working part of the magnetic core blank obtained in step S1 along the radial direction as the splicing segment of the magnetic core. S3. Polish and flatten the cutting section of the splicing segment obtained in step S2, and splice and fixedly connect multiple splicing segments to obtain the magnetic core finished product.

7. The preparation method of the large-sized magnetic core according to claim 6, wherein In steps S2 and S3, the arc angle of the splicing segment is 360° / n, where n is a positive integer, and the range of n is: 2≤n≤18.

8. The preparation method of the large-sized magnetic core according to claim 6, characterized in that, The method of fixedly connecting the splicing segments in step S3 is bonding and fixing with a soft magnetic adhesive or hinge connection and fixing.

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