Magnetic core forming mold and method of manufacturing the same

Abstract

This invention relates to the field of ferrite technology and discloses a magnetic core forming mold and its manufacturing method. The magnetic core forming mold includes: a first mold body having a first cavity; a second mold body disposed within the first cavity; the second mold body is hollow inside, forming a second cavity; the second mold body has a first forming surface, a second forming surface, and a third forming surface, the first forming surface being located on one side of the second mold body along the third direction, the second forming surface surrounding the second cavity circumferentially, and the third forming surface being located on the side of the second mold body opposite to the second cavity; a composite chamfer surface is formed at the junction of the first forming surface and the second forming surface, and at the junction of the first forming surface and the third forming surface; the composite chamfer surface has recesses, and multiple recesses are spaced circumferentially on the composite chamfer surface; a plating layer is disposed within the recesses, and the side of the plating layer opposite to the recesses is flush with the composite chamfer surface. The magnetic core forming mold provided by this invention can enhance the flow effect of magnetic core powder and improve the cracking degree at the junction of magnetic core blanks.

Description

Technical Field

[0001] This invention relates to the field of ferrite technology, specifically to a magnetic core forming mold and its manufacturing method. Background Technology

[0002] Manganese-zinc soft magnetic ferrites possess physicochemical properties such as high permeability, low coercivity, and low power loss, making them widely used in the automotive industry, primarily for manufacturing high-frequency transformers, inductors, and noise filters. As environmental requirements in application fields increase, the strength requirements for ferrites are also becoming more stringent.

[0003] In order to increase the strength of the magnetic core, existing ferrite products usually increase the wall thickness and leg size. However, due to the large density difference at the junction of the core leg root and the base plate, the magnetic core obtained by increasing the wall thickness and leg size is prone to cracking during temperature shock testing, and does not achieve the expected results. Summary of the Invention

[0004] In view of this, the present invention provides a magnetic core forming mold and its manufacturing method to solve the problem of easy cracking at the junction of magnetic cores.

[0005] In a first aspect, the present invention provides a magnetic core forming mold having intersecting first, second, and third directions, comprising:

[0006] The first module has a hollow interior forming a first cavity, which is disposed through the first module in a third direction;

[0007] The second mold body is disposed within the first cavity, and both sides of the second mold body are connected to the first mold body along the second direction; the interior of the second mold body is hollow and forms a second cavity;

[0008] The second mold body has a first molding surface, a second molding surface and a third molding surface. The first molding surface is located on one side of the second mold body along the third direction. The second molding surface surrounds and forms a second cavity along the circumferential direction. The third molding surface is located on the side of the second mold body away from the second cavity. A composite chamfer surface is formed at the junction of the first molding surface and the second molding surface and at the junction of the first molding surface and the third molding surface.

[0009] The composite chamfered surface has recesses, and multiple recesses are spaced apart circumferentially on the composite chamfered surface.

[0010] The coating is located inside the recess, with the side of the coating away from the recess flush with the composite chamfer surface.

[0011] Beneficial Effects: The magnetic core forming mold provided by this invention is used to press magnetic core powder into magnetic core blanks. By forming composite chamfer surfaces at the junctions of the first and second forming surfaces and the junctions of the first and third forming surfaces of the magnetic core forming mold, composite chamfers are formed at the junctions of the magnetic core blanks during the pressing and forming process. Actual test results show that this design effectively avoids through-cracks at the junctions of the magnetic core blanks during high-temperature sintering, improves the cracking degree at the junctions, and increases the strength of the magnetic core. The composite chamfered surface is designed with recesses, with multiple recesses spaced circumferentially to form a groove grid shape. A plating layer is then used to fill the recesses. The recesses effectively prevent plating overflow, and even after polishing, a large amount of plating is retained, ensuring that the side of the plating away from the recesses is flush with the composite chamfered surface. This reduces the roughness of the composite chamfered surface of the magnetic core forming mold. Actual test results show that this design enhances the flow of magnetic core powder, reduces the density difference near the junction of the magnetic core forming blank, and further improves the cracking degree at the junction of the magnetic core blank.

[0012] In one optional embodiment, the composite chamfer surface includes a first transition surface, a second transition surface, and a third transition surface, wherein the first transition surface is a straight chamfer surface, and the second and third transition surfaces are both rounded chamfer surfaces.

[0013] The second transition surface is located between the first transition surface and the first forming surface, and the third transition surface is located between the first transition surface and the second forming surface and the third forming surface;

[0014] The recess includes a first groove and a second groove. The first groove is located at one end of the first transition surface near the second transition surface, and the second groove is located at one end of the first transition surface near the third transition surface.

[0015] Beneficial effects: The magnetic core forming mold forms an "RCR" type composite chamfer surface, and sets a first groove and a second groove on the "RCR" type composite chamfer surface. Both the first groove and the second groove are filled with a plating layer and then polished to obtain the magnetic core forming mold. The actual test results show that after the magnetic core blank formed by the magnetic core forming mold is sintered at high temperature, there are no through cracks on the slope of the first transition angle, and there are no through cracks on the slopes of the second transition angle and the third transition angle, which greatly improves the cracking degree at the junction of the magnetic core blank.

[0016] In one optional embodiment, the first groove includes a first groove segment and a second groove segment. The first groove segment is disposed in the first transition surface region, and one end of the second groove segment is connected to the first groove segment, while the other end extends into the second transition surface region.

[0017] The second groove includes a third groove segment and a fourth groove segment. The third groove segment is located in the first transition surface area, and one end of the fourth groove segment is connected to the first groove segment, while the other end extends into the third transition surface area.

[0018] Beneficial effects: By setting the first groove segment and the second groove segment, the first groove extends into both the first transition surface area and the second transition surface area simultaneously, thereby improving the surface finish at the junction of the first transition surface and the second transition surface through a coating. By setting the third groove segment and the fourth groove segment, the second groove extends into both the first transition surface area and the third transition surface area simultaneously, thereby improving the surface finish at the junction of the first transition surface and the third transition surface through a coating. This further improves the surface finish of the "RCR" type composite chamfered surface, reduces the surface roughness of the "RCR" type composite chamfered surface, effectively ensures the flow effect of the magnetic core powder, and further improves the cracking degree at the junction of the magnetic core blank.

[0019] In one alternative embodiment, the first transition surface has a first right-angled side and a second right-angled side, the first right-angled side being disposed along a third direction, and the second right-angled side being perpendicular to the first right-angled side;

[0020] The length of the first right-angled side is P1, and the length of the second right-angled side is P2. P1 and P2 satisfy 0.518≤P2 / P1≤0.718.

[0021] Beneficial effects: It helps improve the fluidity of magnetic core powder during the pressing and molding process of magnetic core blanks, reduces the density difference near the junction of magnetic core blanks, and further improves the degree of cracking at the junction of magnetic core blanks.

[0022] In one alternative implementation, P1 and P2 satisfy P2 / P1 = 7 / 11.

[0023] Beneficial effects: It not only facilitates processing, but also avoids through cracks appearing on the arc surfaces of the second and third transition angles of the magnetic core.

[0024] In one optional implementation, the chamfer dimension of both the second transition surface and the third transition surface is R, and the value of R is in the range of 0.2mm≤R≤0.7mm.

[0025] In one optional embodiment, the composite chamfer surface includes a first transition surface, a second transition surface, and a third transition surface, wherein the first transition surface, the second transition surface, and the third transition surface are all straight chamfer surfaces;

[0026] The second transition surface is located between the first transition surface and the first forming surface, and the third transition surface is located between the first transition surface and the second forming surface and the third forming surface;

[0027] The recess includes a first groove and a second groove. The first groove is located at one end of the first transition surface near the second transition surface, and the second groove is located at one end of the first transition surface near the third transition surface.

[0028] Beneficial effects: The magnetic core forming mold forms a "CCC" type composite chamfer surface, and sets a first groove and a second groove on the "CCC" type composite chamfer surface. Both the first groove and the second groove are filled with a plating layer and then polished to obtain the magnetic core forming mold. The actual test results show that after the magnetic core blank formed by the magnetic core forming mold is sintered at high temperature, there are no through cracks on the slope of the first transition angle, and there are no through cracks on the slopes of the second transition angle and the third transition angle, which greatly improves the cracking degree at the junction of the magnetic core blank.

[0029] In one optional embodiment, both the second transition surface and the third transition surface have a third right-angled side and a fourth right-angled side, wherein the third right-angled side is perpendicular to the fourth right-angled side;

[0030] The third leg has a dimension of P3, and the fourth leg has a dimension of P4. P3 and P4 satisfy 0 ≤ P3 ≤ P4 ...

[0031]

[0032] Beneficial effects: Prevents the failure of the second and third transition surfaces, and effectively avoids through cracks at the second and third transition angles.

[0033] In one optional embodiment, the composite chamfer surface includes a first transition surface, a second transition surface, and a third transition surface, wherein the first transition surface is a straight chamfer surface, the second transition surface is a rounded chamfer surface, and the third transition surface is a straight chamfer surface.

[0034] The second transition surface is located between the first transition surface and the first forming surface, and the third transition surface is located between the first transition surface and the second forming surface and the third forming surface;

[0035] The recess includes a first groove and a second groove. The first groove is located at one end of the first transition surface near the second transition surface, and the second groove is located at one end of the first transition surface near the third transition surface.

[0036] Beneficial effects: The magnetic core forming mold forms a "CCR" type composite chamfer surface, and sets a first groove and a second groove on the "CCR" type composite chamfer surface. Both the first groove and the second groove are filled with a plating layer and then polished to obtain the magnetic core forming mold. The actual test results show that after the magnetic core blank formed by the magnetic core forming mold is sintered at high temperature, there are no through cracks on the slope of the first transition angle, and there are no through cracks on the slopes of the second transition angle and the third transition angle, which greatly improves the cracking degree at the junction of the magnetic core blank.

[0037] Secondly, the present invention also provides a method for manufacturing the magnetic core forming mold as described above, comprising:

[0038] The process forms a master mold, which includes a first mold body and a second mold body, wherein the second mold body is processed to form a composite chamfered surface;

[0039] A recess is formed by machining the composite chamfered surface;

[0040] A coating is filled into the recess, wherein the coating is a diamond-like carbon coating;

[0041] polishing.

[0042] Beneficial effects: It reduces the roughness of the composite chamfer surface of the magnetic core forming mold, thereby enhancing the flow effect of the magnetic core powder and improving the cracking degree at the junction of the magnetic core blank. Attached Figure Description

[0043] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0044] Figure 1 This is a perspective view of the first type of magnetic core forming mold according to an embodiment of the present invention;

[0045] Figure 2 for Figure 1 A magnified view of a partial cross-section at point A, showing that no coating is applied to the recessed area;

[0046] Figure 3 for Figure 2 A magnified view of a portion of point B in the middle;

[0047] Figure 4 for Figure 2 A schematic diagram showing the coating applied to the recessed area.

[0048] Figure 5 for Figure 1 Top view of the core forming mold;

[0049] Figure 6 for Figure 5 A sectional view of section WW in the middle;

[0050] Figure 7 for Figure 6 A magnified view of a portion of point D in the middle;

[0051] Figure 8 for Figure 7A magnified view of a portion at point E, where no coating is applied to the recessed area;

[0052] Figure 9 for Figure 8 A schematic diagram showing the dimensions of the first transition surface.

[0053] Figure 10 for Figure 8 A schematic diagram showing the coating applied to the recessed area.

[0054] Figure 11 for Figure 5 A magnified view of a portion of point F in the middle;

[0055] Figure 12 This is a partial cross-sectional view of a second type of magnetic core forming mold according to an embodiment of the present invention, wherein no plating layer is provided in the recess;

[0056] Figure 13 This is a partial cross-sectional view of a third type of magnetic core forming mold according to an embodiment of the present invention, wherein no plating layer is provided in the recess.

[0057] Explanation of reference numerals in the attached figures:

[0058] 10. First mold body; 100. First cavity;

[0059] 20. Second mold; 200. Second cavity;

[0060] 21. First forming surface;

[0061] 22. Second forming surface;

[0062] 23. Third forming surface;

[0063] 24. Composite chamfered surface; 241. First transition surface; 2411. First right-angled side; 2412. Second right-angled side; 242. Second transition surface; 2421. Third right-angled side; 2422. Fourth right-angled side; 243. Third transition surface;

[0064] 25. Recess; 251. First groove; 2511. First groove segment; 2512. Second groove segment; 252. Second groove; 2521. Third groove segment; 2522. Fourth groove segment;

[0065] 26. Coating;

[0066] X—first direction; Y—second direction; Z—third direction. Detailed Implementation

[0067] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0068] The following is combined Figures 1 to 13 The following describes embodiments of the present invention.

[0069] According to an embodiment of the present invention, in one aspect, a magnetic core forming mold is provided, having a first direction X, a second direction Y, and a third direction Z intersecting each other, comprising:

[0070] First module 10, please combine them together. Figure 1 and Figure 6 As shown, its interior is hollow and forms a first cavity 100, which is disposed through the first module 10 along the third direction Z.

[0071] The second module 20 is located inside the first cavity 100; please assemble them together. Figure 5 As shown, the second mold 20 is connected to the first mold 10 on both sides along the second direction Y; the second mold 20 is hollow inside and forms a second cavity 200;

[0072] Please combine them together Figure 6 and Figure 11 As shown, the second mold 20 has a first molding surface 21, a second molding surface 22, and a third molding surface 23. The first molding surface 21 is located on one side of the second mold 20 along the third direction Z. The second molding surface 22 surrounds and forms a second cavity 200 along the circumferential direction. The third molding surface 23 is located on the side of the second mold 20 away from the second cavity 200. A composite chamfer surface 24 is formed at the junction of the first molding surface 21 and the second molding surface 22 and at the junction of the first molding surface 21 and the third molding surface 23. The composite chamfer surface 24 is used to form a composite chamfer for the magnetic core blank.

[0073] Please see Figure 2 As shown, the composite chamfered surface 24 is provided with recesses 25, and multiple recesses 25 are provided at intervals along the circumference of the composite chamfered surface 24;

[0074] Please see Figure 4 As shown, the plating layer 26 is disposed in the recess 25, and the side of the plating layer 26 away from the recess 25 is flush with the composite chamfered surface 24.

[0075] It should be noted that the magnetic core blank has a theoretical shrinkage rate of 17% during high-temperature sintering. Different forming densities will result in different shrinkage rates. That is, during sintering, the shrinkage is relatively small in areas with high density and relatively large in areas with low density. When areas with high density and low density meet, tearing is likely to occur at the junction.

[0076] The magnetic core forming mold provided by this invention is used to press magnetic core powder into magnetic core blanks. By forming composite chamfer surfaces 24 at the junctions of the first forming surface 21 and the second forming surface 22 and the junctions of the first forming surface 21 and the third forming surface 23 of the magnetic core forming mold, composite chamfers are formed at the junctions of the magnetic core blanks during the pressing and forming process. Actual test results show that this design effectively avoids through-cracks at the junctions of the magnetic core blanks during high-temperature sintering, improves the cracking degree at the junctions of the magnetic core blanks, and increases the strength of the magnetic core. Furthermore, by providing recesses 24 on the composite chamfer surfaces 24... 5. Multiple recesses 25 are spaced circumferentially on the composite chamfered surface 24 to form a groove grid shape. Then, a plating layer 26 is used to fill the recesses 25. The recesses 25 can effectively prevent the plating layer 26 from overflowing. Even after polishing, the plating layer 26 can be largely retained, thus ensuring that the side of the plating layer 26 away from the recesses 25 is flush with the composite chamfered surface 24. This reduces the roughness of the composite chamfered surface 24 of the magnetic core forming mold. The test results show that this setting can enhance the flow effect of the magnetic core powder, reduce the density difference near the junction of the magnetic core forming blank, and further improve the cracking degree at the junction of the magnetic core blank.

[0077] It should be noted that the composite chamfer surface 24 of the magnetic core forming mold corresponds to the composite chamfer (not shown in the figure) that forms the magnetic core blank. The composite chamfer surface 24 can be an "RCR" type composite chamfer surface, a "CCC" type composite chamfer surface, or a "CCR" type composite chamfer surface, where "R" refers to a circular arc chamfer and "C" refers to a straight line chamfer.

[0078] First, we will use a magnetic core forming mold with an "RCR" type composite chamfered surface as an example.

[0079] In some embodiments, see Figure 7 As shown, the composite chamfered surface 24 includes a first transition surface 241, a second transition surface 242, and a third transition surface 243. The first transition surface 241 is a straight chamfered surface, and the second transition surface 242 and the third transition surface 243 are both rounded chamfered surfaces, thus forming an "RCR" type composite chamfered surface.

[0080] Please combine them together Figure 2As shown, the second transition surface 242 is disposed between the first transition surface 241 and the first forming surface 21, and the third transition surface 243 is disposed between the first transition surface 241 and the second forming surface 22 and the third forming surface 23.

[0081] The recess 25 includes a first groove 251 and a second groove 252. The first groove 251 is located at one end of the first transition surface 241 near the second transition surface 242. Multiple first grooves 251 are evenly spaced around the composite chamfer surface 24. The second groove 252 is located at one end of the first transition surface 241 near the third transition surface 243. Multiple second grooves 252 are evenly spaced around the composite chamfer surface 24, thereby forming a groove grid shape on the "RCR" type composite chamfer surface.

[0082] It should be noted that the first transition surface 241 corresponds to the first transition angle (not shown in the figure) forming the magnetic core blank, the second transition surface 242 corresponds to the second transition angle (not shown in the figure) forming the magnetic core blank, and the third transition surface 243 corresponds to the third transition angle (not shown in the figure) forming the magnetic core blank. The first transition angle is a straight chamfer, while the second and third transition angles are both rounded chamfers. The first groove 251 and the second groove 252 are both filled with a plating layer 26 and then polished to ensure that the side of the plating layer 26 facing away from the recess 25 is flush with the composite chamfer surface 24.

[0083] In this embodiment, the magnetic core forming mold forms an "RCR" type composite chamfered surface, and sets a first groove 251 and a second groove 252 on the "RCR" type composite chamfered surface. The first groove 251 and the second groove 252 are filled with a plating layer 26, and then polished to obtain the magnetic core forming mold. The actual test results show that after the magnetic core blank formed by the magnetic core forming mold is sintered at high temperature, there are no through cracks on the slope of the first transition angle, and there are no through cracks on the slopes of the second transition angle and the third transition angle, which greatly improves the cracking degree at the junction of the magnetic core blank.

[0084] In some embodiments, see Figure 3 As shown, the first groove 251 includes a first groove segment 2511 and a second groove segment 2512. The first groove segment 2511 is located in the area of ​​the first transition surface 241. One end of the second groove segment 2512 is connected to the first groove segment 2511, and the other end extends into the area of ​​the second transition surface 242.

[0085] The second groove 252 includes a third groove segment 2521 and a fourth groove segment 2522. The third groove segment 2521 is located in the area of ​​the first transition surface 241. One end of the fourth groove segment 2522 is connected to the first groove segment 2511, and the other end extends into the area of ​​the third transition surface 243.

[0086] In this embodiment, by setting a first groove segment 2511 and a second groove segment 2512, the first groove 251 extends simultaneously into the regions of the first transition surface 241 and the second transition surface 242, thereby improving the surface finish at the junction between the first transition surface 241 and the second transition surface 242 through the plating layer 26. By setting a third groove segment 2521 and a fourth groove segment 2522, the second groove 252 extends simultaneously into the regions of the first transition surface 241 and the third transition surface 243, thereby improving the surface finish at the junction between the first transition surface 241 and the third transition surface 243 through the plating layer 26. This improves the surface finish of the "RCR" type composite chamfered surface, reduces the surface roughness of the "RCR" type composite chamfered surface, effectively ensures the flow effect of the magnetic core powder, and further improves the cracking degree at the junction of the magnetic core blank.

[0087] In some embodiments, see Figure 9 As shown, the first transition surface 241 has a first right-angled side 2411 and a second right-angled side 2412. The first right-angled side 2411 is arranged along the third direction Z, and the second right-angled side 2412 is perpendicular to the first right-angled side 2411.

[0088] The first right-angled side 2411 has a dimension of P1, and the second right-angled side 2412 has a dimension of P2. P1 and P2 satisfy 0.518≤P2 / P1≤0.718. For example, the value of P2 / P1 can be 0.518, 0.6, 0.618, 0.7 or 0.718.

[0089] In this embodiment, the first transition surface 241, by satisfying 0.518≤P2 / P1≤0.718, helps to improve the fluidity of the magnetic core powder during the pressing and molding process of the magnetic core blank, reduces the density difference near the junction of the magnetic core blank, and further improves the degree of cracking at the junction of the magnetic core blank.

[0090] In some embodiments, P1 and P2 satisfy P2 / P1 = 7 / 11, which not only helps to improve the flowability of the magnetic core powder during the pressing and molding process of the magnetic core blank, but also helps to disperse the stress in the magnetic core structure, thereby extending the service life of the ferrite structure.

[0091] In some embodiments, see Figure 8 As shown, the chamfer dimensions of the second transition surface 242 and the third transition surface 243 are both R, and the value of R is in the range of 0.2mm≤R≤0.7mm. This not only facilitates processing, but also avoids through cracks on the arc surfaces of the second and third transition angles of the magnetic core.

[0092] Next, we will use a magnetic core forming mold with a "CCC" type composite chamfered surface as an example.

[0093] In some embodiments, see Figure 12 As shown, the composite chamfered surface 24 includes a first transition surface 241, a second transition surface 242, and a third transition surface 243. The first transition surface 241, the second transition surface 242, and the third transition surface 243 are all straight chamfered surfaces, thus forming a "CCC" type composite chamfered surface.

[0094] The second transition surface 242 is disposed between the first transition surface 241 and the first forming surface 21, and the third transition surface 243 is disposed between the first transition surface 241 and the second forming surface 22 and the third forming surface 23.

[0095] The recess 25 includes a first groove 251 and a second groove 252. The first groove 251 is located at one end of the first transition surface 241 near the second transition surface 242, and the second groove 252 is located at one end of the first transition surface 241 near the third transition surface 243, thereby forming a groove grid shape on the "CCC" type composite chamfered surface.

[0096] It should be noted that the first transition surface 241 corresponds to the first transition angle (not shown in the figure) forming the magnetic core blank, the second transition surface 242 corresponds to the second transition angle (not shown in the figure) forming the magnetic core blank, and the third transition surface 243 corresponds to the third transition angle (not shown in the figure) forming the magnetic core blank. The first, second, and third transition angles are all straight chamfers. The first groove 251 and the second groove 252 are both filled with a plating layer 26 and then polished to ensure that the side of the plating layer 26 facing away from the groove 25 is flush with the composite chamfer surface 24.

[0097] In this embodiment, the magnetic core forming mold forms a "CCC" type composite chamfered surface, and sets a first groove 251 and a second groove 252 on the "CCC" type composite chamfered surface. The first groove 251 and the second groove 252 are filled with a plating layer 26, and then polished to obtain the magnetic core forming mold. The actual test results show that after the magnetic core blank formed by the magnetic core forming mold is sintered at high temperature, there are no through cracks on the slope of the first transition angle, and there are no through cracks on the slopes of the second transition angle and the third transition angle, which greatly improves the cracking degree at the junction of the magnetic core blank.

[0098] It should be noted that the first transition surface 241 of the "CCC" type composite chamfer surface has the same specific structural parameters and working principle as the first transition surface 241 of the "RCR" type composite chamfer surface. The working principle of the coating 26 in the recess 25 of the "CCC" type composite chamfer surface is the same as that in the recess 25 of the "RCR" type composite chamfer surface, and will not be described again here.

[0099] In some embodiments, see Figure 12As shown, both the second transition surface 242 and the third transition surface 243 have a third right-angled side 2421 and a fourth right-angled side 2422, and the third right-angled side 2421 and the fourth right-angled side 2422 are perpendicular to each other.

[0100] The dimension of the third right-angled leg 2421 is P3, and the dimension of the fourth right-angled leg 2422 is P4. P3 and P4 satisfy... This avoids the failure of the second transition surface 242 and the third transition surface 243, and effectively prevents through cracks from appearing at the second transition angle and the third transition angle.

[0101] Finally, the core forming mold with a "CCR" type composite chamfered surface will be used as an example.

[0102] In some embodiments, see Figure 13 As shown, the composite chamfer surface 24 includes a first transition surface 241, a second transition surface 242, and a third transition surface 243. The first transition surface 241 is a straight chamfer surface, the second transition surface 242 is a rounded chamfer surface, and the third transition surface 243 is a straight chamfer surface, thereby forming a "CCR" type composite chamfer surface.

[0103] The second transition surface 242 is disposed between the first transition surface 241 and the first forming surface 21, and the third transition surface 243 is disposed between the first transition surface 241 and the second forming surface 22 and the third forming surface 23.

[0104] The recess 25 includes a first groove 251 and a second groove 252. The first groove 251 is located at one end of the first transition surface 241 near the second transition surface 242, and the second groove 252 is located at one end of the first transition surface 241 near the third transition surface 243, thereby forming a groove grid shape on the "CCR" type composite chamfered surface.

[0105] It should be noted that the first transition surface 241 corresponds to the first transition angle (not shown in the figure) forming the magnetic core blank, the second transition surface 242 corresponds to the second transition angle (not shown in the figure) forming the magnetic core blank, and the third transition surface 243 corresponds to the third transition angle (not shown in the figure) forming the magnetic core blank. The first transition angle is a straight chamfer, the second transition angle is a rounded chamfer, and the third transition angle is a straight chamfer. Both the first groove 251 and the second groove 252 are filled with a plating layer 26 and then polished to ensure that the side of the plating layer 26 facing away from the recess 25 is flush with the composite chamfer surface 24.

[0106] In this embodiment, the magnetic core forming mold forms a "CCR" type composite chamfered surface, and sets a first groove 251 and a second groove 252 on the "CCR" type composite chamfered surface. The first groove 251 and the second groove 252 are filled with a plating layer 26, and then polished to obtain the magnetic core forming mold. The actual test results show that after the magnetic core blank formed by the magnetic core forming mold is sintered at high temperature, there are no through cracks on the slope of the first transition angle, and there are no through cracks on the slopes of the second transition angle and the third transition angle, which greatly improves the cracking degree at the junction of the magnetic core blank.

[0107] It should be noted that the first transition surface 241 of the "CCR" type composite chamfer surface has the same specific structural parameters and working principle as the first transition surface 241 of the "RCR" type composite chamfer surface. The working principle of the coating 26 in the recess 25 of the "CCR" type composite chamfer surface is the same as that in the recess 25 of the "RCR" type composite chamfer surface, and will not be described again here.

[0108] According to an embodiment of the present invention, in another aspect, a method for manufacturing a magnetic core forming mold as described above is also provided, comprising:

[0109] The process forms a master mold, which includes a first mold body 10 and a second mold body 20, wherein the second mold body 20 is processed to form a composite chamfered surface 24;

[0110] A recess 25 is formed by machining the composite chamfered surface 24;

[0111] A coating 26 is filled in the recess 25, wherein the coating 26 is a diamond-like carbon coating 26;

[0112] polishing.

[0113] It should be noted that the composite chamfered surface 24 of the magnetic core forming mold can be processed by electrical discharge machining, electrochemical machining, or laser machining, without specific limitations here; the recess 25 can be processed by electrochemical machining or laser machining, without specific limitations here. The diamond-like carbon coating 26 is also called a DLC (Diamond-Like Carbon) coating.

[0114] After the composite chamfered surface 24 is processed to form the recess 25, the composite chamfered surface 24 and the recess 25 are polished to ensure the smoothness of the composite chamfered surface 24 and the recess 25. Then, the recess 25 is filled with the plating layer 26 and polished again. The recess 25 can effectively prevent the overflow of the plating layer 26. Even after polishing, the plating layer 26 can be largely retained, thereby ensuring that the side of the plating layer 26 away from the recess 25 is flush with the composite chamfered surface 24. This reduces the roughness of the composite chamfered surface 24 of the magnetic core forming mold, thereby enhancing the flow effect of the magnetic core powder and improving the degree of cracking at the junction of the magnetic core blank.

[0115] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A magnetic core forming mold, having intersecting first direction (X), second direction (Y), and third direction (Z), characterized in that, include: A first mold (10) is hollow inside and forms a first cavity (100), the first cavity (100) being disposed through the first mold (10) along the third direction (Z); The second mold (20) is disposed inside the first cavity (100), and the second mold (20) is connected to the first mold (10) on both sides along the second direction (Y); the second mold (20) is hollow inside and forms a second cavity (200); The second mold (20) has a first molding surface (21), a second molding surface (22) and a third molding surface (23). The first molding surface (21) is located on one side of the second mold (20) along the third direction (Z). The second molding surface (22) surrounds the second cavity (200) in the circumferential direction. The third molding surface (23) is located on the side of the second mold (20) away from the second cavity (200). The junction of the first molding surface (21) and the second molding surface (22) and the junction of the first molding surface (21) and the third molding surface (23) are both formed with a composite chamfer surface (24). The composite chamfered surface (24) is provided with recesses (25), and a plurality of recesses (25) are provided circumferentially spaced on the composite chamfered surface (24); A plating layer (26) is disposed in the recess (25), and the side of the plating layer (26) facing away from the recess (25) is flush with the composite chamfered surface (24).

2. The magnetic core forming mold according to claim 1, characterized in that, The composite chamfered surface (24) includes a first transition surface (241), a second transition surface (242), and a third transition surface (243). The first transition surface (241) is a straight chamfered surface, and the second transition surface (242) and the third transition surface (243) are both arc chamfered surfaces. The second transition surface (242) is disposed between the first transition surface (241) and the first forming surface (21), and the third transition surface (243) is disposed between the first transition surface (241) and the second forming surface (22) and the third forming surface (23); The recess (25) includes a first groove (251) and a second groove (252). The first groove (251) is located at one end of the first transition surface (241) near the second transition surface (242), and the second groove (252) is located at one end of the first transition surface (241) near the third transition surface (243).

3. The magnetic core forming mold according to claim 2, characterized in that, The first groove (251) includes a first groove segment (2511) and a second groove segment (2512). The first groove segment (2511) is located in the area of ​​the first transition surface (241). One end of the second groove segment (2512) is connected to the first groove segment (2511), and the other end extends into the area of ​​the second transition surface (242). The second groove (252) includes a third groove segment (2521) and a fourth groove segment (2522). The third groove segment (2521) is located in the area of ​​the first transition surface (241). One end of the fourth groove segment (2522) is connected to the first groove segment (2511), and the other end extends into the area of ​​the third transition surface (243).

4. The magnetic core forming mold according to claim 2, characterized in that, The first transition surface (241) has a first right-angled side (2411) and a second right-angled side (2412), the first right-angled side (2411) is arranged along the third direction (Z), and the second right-angled side (2412) is perpendicular to the first right-angled side (2411); The first right-angled side (2411) has a size of P1, and the second right-angled side (2412) has a size of P2. P1 and P2 satisfy 0.518≤P2 / P1≤0.

718.

5. The magnetic core forming mold according to claim 4, characterized in that, P1 and P2 satisfy P2 / P1 = 7 / 11.

6. The magnetic core forming mold according to claim 2, characterized in that, The chamfer dimensions of the second transition surface (242) and the third transition surface (243) are both R, and the value of R is in the range of 0.2mm≤R≤0.7mm.

7. The magnetic core forming mold according to claim 1, characterized in that, The composite chamfered surface (24) includes a first transition surface (241), a second transition surface (242), and a third transition surface (243), wherein the first transition surface (241), the second transition surface (242), and the third transition surface (243) are all straight chamfered surfaces; The second transition surface (242) is disposed between the first transition surface (241) and the first forming surface (21), and the third transition surface (243) is disposed between the first transition surface (241) and the second forming surface (22) and the third forming surface (23); The recess (25) includes a first groove (251) and a second groove (252). The first groove (251) is located at one end of the first transition surface (241) near the second transition surface (242), and the second groove (252) is located at one end of the first transition surface (241) near the third transition surface (243).

8. The magnetic core forming mold according to claim 7, characterized in that, The second transition surface (242) and the third transition surface (243) each have a third right-angled side (2421) and a fourth right-angled side (2422), wherein the third right-angled side (2421) is perpendicular to the fourth right-angled side (2422); The dimension of the third right-angled side (2421) is P3, and the dimension of the fourth right-angled side (2422) is P4, where P3 and P4 satisfy...

9. The magnetic core forming mold according to claim 1, characterized in that, The composite chamfered surface (24) includes a first transition surface (241), a second transition surface (242), and a third transition surface (243). The first transition surface (241) is a straight chamfered surface, the second transition surface (242) is a rounded chamfered surface, and the third transition surface (243) is a straight chamfered surface. The second transition surface (242) is disposed between the first transition surface (241) and the first forming surface (21), and the third transition surface (243) is disposed between the first transition surface (241) and the second forming surface (22) and the third forming surface (23); The recess (25) includes a first groove (251) and a second groove (252). The first groove (251) is located at one end of the first transition surface (241) near the second transition surface (242), and the second groove (252) is located at one end of the first transition surface (241) near the third transition surface (243).

10. A method for manufacturing a magnetic core forming mold as described in any one of claims 1 to 9, characterized in that, include: The process forms a master mold, which includes a first mold body (10) and a second mold body (20), wherein the second mold body (20) is processed to form a composite chamfered surface (24); A recess (25) is formed by machining the composite chamfered surface (24); A coating (26) is filled in the recess (25), wherein the coating (26) is a diamond-like carbon coating; polishing.

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