Multi-pole radial magnetic ring die

Abstract

The utility model relates to the technical field of magnet preparation molds, and discloses a multi-pole radial magnetic ring mold, which comprises a sleeve body, a plurality of radial magnetic rings and a plurality of radial magnetic rings, the multiple magnet structures are arranged on the outer side of the sleeve body, and the multiple magnet structures are distributed in the circumferential direction of the sleeve body at intervals; the shielding blocks are arranged on the outer side of the sleeve body, the number of the shielding blocks is equal to that of the magnet structures, and each shielding block is located between every two adjacent magnet structures. The magnet structures are arranged on the outer side of the sleeve body, the magnet structures generate an external orientation magnetic field, the magnet ring is oriented in the forming process of the magnet ring, the magnet structures are distributed in the circumferential direction of the sleeve body at intervals so that the magnet ring can be of a multi-pole radial structure, and one shielding block is arranged between every two adjacent magnet structures so that the trend of the magnetic field can be changed; the interference of a magnetic field on a concave mold cavity is reduced, so that the orientation force at the joint of two adjacent magnetic poles on the magnetic ring is reduced, the influence on a formed blank is reduced, and the phenomenon that the sintered magnetic ring cracks is reduced.

Description

Technical Field

[0001] This utility model relates to the field of magnet manufacturing mold technology, specifically to a multi-pole radial magnetic ring mold. Background Technology

[0002] Multipole magnetic rings are a common name for rotors with two or more poles. Their manufacturing process includes material preparation, pressing, sintering, and grinding. During the pressing process, the mold plays a crucial role in shaping. For multipole radial magnetic rings made from dry magnetic powder, an external magnetic field is added to the mold during the forming process for orientation, making it easier for the magnetic ring to form a multipole distribution in the circumferential direction, thus improving the accuracy of the magnetic pole distribution. In the pressing process of multipole radial magnetic rings, the structure and design of the mold directly determine the formation of the orientation surface on the magnetic ring. Existing technologies use multiple magnetic blocks arranged around the inner sleeve of the mold to add an external magnetic field. However, due to the influence of the magnetic field between the magnetic blocks, the difference in magnetic field strength near the orientation and non-orientation surfaces of the magnetic ring blank after forming and sintering is too large. This easily leads to cracking at the connection point between two adjacent magnetic poles (referred to as the zero point), resulting in a low yield rate for the magnetic rings. Utility Model Content

[0003] In view of this, the present invention provides a multi-pole radial magnetic ring mold to solve the problem of magnetic rings being prone to cracking.

[0004] This utility model provides a multi-pole radial magnetic ring mold, comprising: a sleeve body, which is cylindrical in shape; multiple magnetic structures disposed on the outside of the sleeve body, the multiple magnetic structures being circumferentially spaced around the sleeve body; and multiple shielding blocks disposed on the outside of the sleeve body, the number of shielding blocks being equal to the number of magnetic structures, each shielding block being located between two adjacent magnetic structures.

[0005] Beneficial effects: By setting the sleeve to a cylindrical shape, the inner side of the cylinder forms a concave mold cavity, providing support and housing space for the magnetic ring. By setting a magnetic structure on the outer side of the sleeve, the magnetic structure acts as a magnetic pole head to generate an external orientation magnetic field, realizing the orientation of the magnetic ring during the molding process. Multiple magnetic structures are circumferentially spaced around the sleeve, which can make the magnetic ring a multi-pole radial structure. At the same time, by setting a shielding block between each pair of adjacent magnetic structures, the direction of the magnetic field can be changed, which can reduce the interference of the magnetic field between the magnetic structures on the concave mold cavity, thereby reducing the orientation force at the connection between two adjacent magnetic poles on the magnetic ring, thus reducing the impact on the molding blank, reducing the cracking of the magnetic ring after sintering, improving the yield of the magnetic ring, increasing production efficiency, and reducing production costs.

[0006] In one optional embodiment, the inner wall of the sleeve has an alternating concave-convex shape along the circumference of the sleeve. The inner wall of the sleeve includes protruding sections and recessed sections. The number of recessed sections is equal to the number of magnet structures and corresponds one-to-one. The number of protruding sections is equal to the number of recessed sections, and each protruding section is connected between two adjacent recessed sections.

[0007] Beneficial effects: By setting the inner wall of the sleeve to have an alternating concave-convex shape along its circumference, and setting the inner diameter of the concave mold cavity to have an alternating size structure, the concave sections on the inner wall of the sleeve correspond to the magnet structure, so that the position with larger shrinkage after blank sintering corresponds to the position with larger inner diameter of the sleeve, and the convex sections on the inner wall of the sleeve correspond to the interval between two adjacent magnet structures, so that the position with smaller shrinkage after blank sintering corresponds to the position with smaller inner diameter of the sleeve. As a result, after the magnetic ring is sintered, the shrunken blank is closer to a circle, making the grinding amount at different positions along the circumference of the blank almost consistent, thereby reducing the grinding amount, improving production efficiency, and reducing production costs.

[0008] In one alternative embodiment, the raised section and the recessed section have a smooth transition;

[0009] Wherein, both the protruding segment and the recessed segment are arc segments, and the orthographic projection of the inner wall of the sleeve on a cross section perpendicular to the center line of the sleeve is quincunx-shaped; or, the protruding segment is a straight segment, the recessed segment is an arc segment, and the orthographic projection of the inner wall of the sleeve on a cross section perpendicular to the center line of the sleeve is polygonal.

[0010] Beneficial effects: By setting a smooth transition between the raised and recessed sections, and by setting both the raised and recessed sections to be arc sections, and setting the concave mold cavity to be plum blossom-shaped, the smoothness of the concave mold cavity is further increased, thereby ensuring the smoothness of the outer peripheral surface of the blank, reducing burrs and stress concentration, and facilitating subsequent grinding processing.

[0011] By setting the raised section as a straight line and the recessed section as an arc, the smoothness of the inner wall of the sleeve is ensured on the one hand, and the blank allowance at the transition part between the small diameter and the large diameter is reduced on the other hand, so that the outer circumferential surface of the sintered blank is closer to a circle, further reducing the grinding amount.

[0012] In one optional embodiment, the shielding block has a circumferential dimension of H along the sleeve, and the distance between two adjacent magnet structures along the circumferential direction of the sleeve is K, wherein H and K satisfy the following condition: 1 / 2 ≤ H / K ≤ 2 / 3.

[0013] Beneficial effects: By setting the ratio H / K between the circumferential dimension H of the shielding block and the circumferential distance K between two adjacent magnet structures to a value in the range of 1 / 2 to 2 / 3, the shielding block has a suitable size in the circumferential direction of the sleeve. This ensures that the shielding block has a sufficiently effective shielding effect, thereby reducing the interference of the magnetic field between two adjacent magnet structures on the zero position and reducing the cracking of the magnetic ring. At the same time, it can also avoid the shielding performance of the shielding block being too strong and affecting the magnetic performance of the magnetic ring.

[0014] In one optional embodiment, the thickness of the shielding block along the radial direction of the sleeve is b, wherein the value of b ranges from 3mm to 5mm.

[0015] Beneficial effects: By setting the thickness b of the shielding block along the radial direction of the sleeve to a value within the range of 3mm to 5mm, it is possible to ensure that the shielding block has a sufficiently effective shielding effect, thereby reducing the interference of the magnetic field between two adjacent magnet structures on the zero position, so as to reduce the cracking of the magnetic ring, and also to avoid the shielding performance of the shielding block being too strong, which would affect the magnetic performance of the magnetic ring.

[0016] In one optional embodiment, the distance from the shielding block to the outer peripheral surface of the sleeve along the radial direction of the sleeve is a, wherein the value of a ranges from 2mm to a to 4mm.

[0017] Beneficial effects: By setting the distance 'a' from the radial direction of the shielding block to the outer circumference of the sleeve to be between 2mm and 4mm, the shielding block can have a suitable shielding effect. This can avoid the shielding performance of the shielding block being too strong and affecting the magnetic properties of the magnetic ring, while ensuring that the shielding block has a sufficiently effective shielding effect. This reduces the interference of the magnetic field between two adjacent magnet structures on the zero position, thereby reducing the cracking of the magnetic ring.

[0018] In one alternative implementation, the height of the shielding block is equal to the height of the magnet structure.

[0019] Beneficial effect: By setting the height of the shielding block relative to the height of the magnet structure, the shielding block is guaranteed to have a shielding effect along the height direction of the magnet structure, thereby ensuring the shielding effect.

[0020] In one optional embodiment, an annular magnetic conductor is sleeved on the outer side of the sleeve body, and multiple grooves are formed on the inner circumference of the magnetic conductor to divide the magnetic conductor into multiple magnetic structures, and winding groups are arranged in the grooves.

[0021] Beneficial effects: By opening multiple grooves on the inner circumference of the magnetic conductor, the side of the magnetic conductor near the sleeve is divided into multiple magnetic structures, achieving a circumferentially spaced distribution of multiple magnetic structures around the sleeve. Furthermore, by setting winding groups in the grooves, when current flows through the winding groups, the magnetic structures are magnetized and generate magnetism, thereby applying a magnetic field to the concave mold cavity, achieving the orientation of the magnetic ring in the concave mold cavity. The presence or absence of the magnetic field can be flexibly adjusted as needed, avoiding the magnetic field affecting the powder added to the concave mold cavity during the magnetic ring forming process. It is suitable for mass production and has high efficiency. Moreover, the multiple magnetic structures are fixedly connected. By sleeved on the outside of the sleeve, it is easy to fix the multiple magnetic structures to the sleeve and ensure the stability of their positional relationship.

[0022] In one alternative embodiment, the groove is filled with adhesive.

[0023] Beneficial effects: By filling the groove with glue, the winding assembly and shielding block in the groove are radially fixed, thereby achieving relative fixation between the winding assembly and shielding block and the magnetic conductor, which improves the stability of the entire mold structure and ensures the processing effect.

[0024] In one optional embodiment, the sleeve is made of cemented carbide;

[0025] And / or, the magnetic conductor is pure iron.

[0026] Beneficial effects: Hard alloy has high hardness and wear resistance, high strength and toughness and good stability, which ensures that the die can maintain the precise cavity shape during the pressing of magnetic rings, ensure the consistency of the magnetic ring shape, and has a long service life, reducing the cost of replacing the die and also helping to improve the yield of magnetic rings.

[0027] Pure iron has high magnetic permeability, which can effectively enhance the magnetic field strength and improve the utilization efficiency of the magnetic field. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of this utility model 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 this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a top view of a die according to an embodiment of the present utility model;

[0030] Figure 2 for Figure 1 A partially enlarged schematic diagram of the die shown;

[0031] Figure 3 for Figure 1 A schematic diagram of the inner circumferential surface structure of the display sleeve of the aforementioned concave mold;

[0032] Figure 4 for Figure 3 A partially enlarged schematic diagram of the die shown;

[0033] Figure 5 This is a schematic diagram showing the positional relationship between the sleeve, the magnetic conductor, and the shielding block in an embodiment of the present invention.

[0034] Figure 6 This is a schematic diagram of the structure of a sleeve according to an embodiment of the present utility model;

[0035] Figure 7 This is a schematic diagram of another sleeve structure according to an embodiment of the present utility model;

[0036] Figure 8 This is a simulation diagram of the magnetic field line distribution in the concave mold according to an embodiment of the present invention;

[0037] Figure 9 This is a simulation diagram of the magnetic field line distribution in a concave mold without a shielding block.

[0038] Explanation of reference numerals in the attached figures:

[0039] 1. Sleeve body; 101. Raised section; 102. Recessed section; 103. Large diameter; 104. Small diameter; 2. Magnetic conductor; 201. Magnetic structure; 202. Groove; 203. Winding assembly; 3. Shielding block; 4. Core rod; 5. Magnetic lines of force. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0041] Multipole radial magnetic rings exhibit a state of alternating magnetic poles along their circumference. They can be made from dry powder magnetic material and are anisotropic magnets. Anisotropic magnets have significantly higher magnetic properties than like magnets. During the ring forming process, an external magnetic field is added to the mold for orientation. The difference in magnetic field strength near the magnetic pole orientation surface and the non-magnetic pole orientation surface is too large. The radial shrinkage ratio of the sintered magnet is between 1.15 and 1.35. The large difference in radial shrinkage makes it easy for cracks to form at the connection point between two adjacent magnetic poles (called the zero point). The large grinding allowance affects the production qualification rate and production efficiency of the magnetic rings.

[0042] The following is combined Figures 1 to 9 The following describes embodiments of the present invention.

[0043] According to an embodiment of this utility model, a multi-pole radial magnetic ring mold is provided. The multi-pole radial magnetic ring mold consists of an upper mold, a concave mold, a lower mold, and a mold frame, wherein the concave mold is the core component, the mold frame is the basic support structure, and the upper mold and lower mold cooperate with each other, acting on the concave mold to realize the forming of the multi-pole radial magnetic ring. Figures 1 to 7 As shown, the concave mold of the multi-pole radial magnetic ring mold includes: a sleeve 1, multiple magnetic structures 201, and multiple shielding blocks 3. The sleeve 1 is cylindrical; the multiple magnetic structures 201 are disposed on the outer side of the sleeve 1, and the multiple magnetic structures 201 are distributed circumferentially around the sleeve 1 at intervals; the multiple shielding blocks 3 are disposed on the outer side of the sleeve 1, and the number of shielding blocks 3 is equal to the number of magnetic structures 201, with each shielding block 3 located between two adjacent magnetic structures 201. The outer side of the sleeve 1 refers to the side of the cylindrical sleeve 1 that points radially away from the centerline of the sleeve 1.

[0044] The multi-pole radial magnetic ring mold of this embodiment uses a cylindrical sleeve 1 with a concave mold cavity on the inner side to provide support and housing space for the magnetic ring. A magnetic structure 201 is set on the outer side of the sleeve 1, which acts as a magnetic pole head to generate an external orientation magnetic field, thus orienting the magnetic ring during the molding process. Multiple magnetic structures 201 are circumferentially spaced around the sleeve 1, allowing the magnetic ring to have a multi-pole radial structure. Furthermore, by setting a shielding block 3 between every two adjacent magnetic structures 201, the direction of the magnetic field is changed, reducing the interference of the magnetic field between the magnetic structures 201 on the concave mold cavity. This reduces the orientation force at the connection point of two adjacent magnetic poles on the magnetic ring, thereby reducing the impact on the molding blank, reducing cracking of the magnetic ring after sintering, improving the yield rate of the magnetic ring, increasing production efficiency, and reducing production costs.

[0045] It should be noted that the magnetic ring is a multi-pole radial magnetic ring. To determine the required number of radial poles, several magnetic structures 201 are placed on the outside of the sleeve 1 as magnetic pole heads, acting as the N and S poles. After the magnetic ring blank is formed, oriented, and sintered, the difference in magnetic field strength near the magnetic pole orientation surface and the non-magnetic pole orientation surface is too large, resulting in significant shrinkage differences. This occurs at the connection point (referred to as the zero point, specifically...). Figure 1 The line connecting the center point of the middle sleeve 1 and the center point of the shielding block 3 is prone to cracking, which is related to the orientation magnetic field. By adding a shielding block 3 between two adjacent magnetic structures 201, the interference of the magnetic field between the magnetic structures 201 on the concave model cavity can be reduced, the orientation force at the zero position can be reduced, and the cracking of the magnetic ring can be reduced.

[0046] Specifically, Figure 8The diagram shown is a simulation of the magnetic field distribution in the concave mold equipped with a shielding block according to this embodiment. Figure 9 This is a simulation diagram of the magnetic field line distribution in a concave mold without a traditional shielding block, combined with... Figure 8 and Figure 9 It can be seen that after adding shielding block 3, the direction of the magnetic field is changed, and the magnetic field lines at the zero position become sparse. This indicates that adding shielding block 3 can effectively reduce the orientation force of the magnetic field at the zero position, thereby effectively reducing the cracking phenomenon after the magnetic ring is sintered.

[0047] It should be noted that a concave mold cavity is formed on the inner side of the sleeve 1, and the magnetic ring is located inside the concave mold cavity. The shape of the outer wall of the magnetic ring is determined by the shape of the inner wall of the sleeve 1. The multi-pole radial magnetic ring mold also includes a core rod 4, which is located at the center of the sleeve 1. The magnetic ring is located between the outer peripheral wall of the core rod 4 and the inner wall of the sleeve 1, so that the magnetic ring is annular, thereby forming a magnetic ring.

[0048] Preferably, the magnetic ring produced by the multi-pole radial magnetic ring mold of this embodiment is a permanent magnet ferrite, specifically a multi-pole dry powder pressed radial magnetic ring. The multi-pole radial magnetic ring mold of this embodiment is suitable for magnetic rings with two or more poles, and correspondingly, the number of magnet structures 201 is two or more.

[0049] In one embodiment, further combination Figure 2 As shown, the inner wall of the sleeve 1 has an alternating concave and convex shape along the circumference of the sleeve 1. The recessed parts on the inner wall of the sleeve 1 correspond to the magnet structure 201. The inner wall of the sleeve 1 includes protruding sections 101 and recessed sections 102. The number of recessed sections 102 is equal to the number of magnet structures 201 and they correspond one-to-one. The number of protruding sections 101 is equal to the number of recessed sections 102, and each protruding section 101 is connected between two adjacent recessed sections 102. It should be noted that after magnetic field orientation, the shrinkage of the blank after sintering will be different. The difference in magnetic field strength near the magnetic pole orientation surface and the non-magnetic pole orientation surface is too large. The shrinkage at the position corresponding to the magnetic structure 201 (i.e. the position corresponding to the magnetic pole head) on the blank is larger, while the dimensional shrinkage at the position corresponding to the non-magnetic structure 201 (i.e. the non-magnetic pole head) is smaller. The difference in shrinkage in the radial direction of the magnet sintering is large. If the inner wall of the sleeve 1 is a flat circular surface along its circumference, the outer circumference of the blank after sintering will show obvious unevenness along its circumference, and the grinding amount at the protruding position is larger.

[0050] Therefore, by setting the inner wall of the sleeve 1 to have an alternating concave-convex shape along its circumference, and setting the inner diameter of the concave mold cavity to an alternating size structure, the concave section 102 on the inner wall of the sleeve 1 corresponds to the magnet structure 201, so that the position with larger shrinkage after blank sintering corresponds to the position with larger inner diameter of the sleeve 1, and the convex section 101 on the inner wall of the sleeve 1 corresponds to the interval between two adjacent magnet structures 201, so that the position with smaller shrinkage after blank sintering corresponds to the position with smaller inner diameter of the sleeve 1. Thus, after the magnetic ring is sintered, the shrunken blank is closer to a circle, making the grinding amount at different positions along the circumference of the blank almost consistent, thereby reducing the grinding amount, improving production efficiency, and reducing production costs.

[0051] In this embodiment, the multi-pole radial magnetic ring mold designs the cavity size based on the shrinkage corresponding to the strong and weak magnetic positions of the blank. Areas with large shrinkage have larger dimensions, and areas with small shrinkage have smaller dimensions. This is further combined with… Figures 3 to 4 As shown, the inner diameter of the sleeve 1 corresponding to the recessed part on the inner wall of the sleeve 1 is called the major diameter 103, and the inner diameter of the sleeve 1 corresponding to the protruding part on the inner wall of the sleeve 1 is called the minor diameter 104. The minor diameter 104 is smaller than the major diameter 103. The problem of large grinding amount of magnetic ring blank is solved by optimizing the inner wall structure of the sleeve 1.

[0052] In one embodiment, the raised section 101 and the recessed section 102 have a smooth transition, further integrating the body. Figures 1 to 6 As shown, both the raised section 101 and the recessed section 102 are arc segments, and the orthographic projection of the inner wall of the sleeve 1 onto a section perpendicular to the center line of the sleeve 1 is quincunx-shaped. By setting a smooth transition between the raised section 101 and the recessed section 102, and by setting both the raised section 101 and the recessed section 102 to be arc segments, and by setting the concave mold cavity to be quincunx-shaped, the smoothness of the concave mold cavity is further increased, thereby ensuring the smoothness of the outer circumferential surface of the blank, reducing burrs and stress concentration, and facilitating subsequent grinding processing.

[0053] It should be noted that the concave mold cavity is shaped like a plum blossom, and the magnetic rings are configured with several concave and convex dimensions corresponding to the number of pole magnetic rings. The arc of the raised segment 101 is r, and the arc of the concave segment 102 is R, where R is greater than r. The major diameter 103 and minor diameter 104 of the inner wall of the sleeve 1 are connected by an arc segment, resulting in good smoothness. The shrinkage of the minor diameter 104 is between 1.15 and 1.2, and the shrinkage of the major diameter 103 is between 1.28 and 1.35. Specifically, the major diameter dimension = (original outer diameter + grinding allowance) × major diameter shrinkage amount, and the minor diameter dimension = (original outer diameter + grinding allowance) × minor diameter shrinkage amount.

[0054] Additionally, in other embodiments, such as Figure 7As shown, the protruding segment 101 is a straight line segment, and the recessed segment 102 is an arc segment. The straight line segment protrudes towards the center of the sleeve 1 relative to the arc segment, and there is a smooth transition between the straight line segment and the arc segment. The orthographic projection of the inner wall of the sleeve 1 onto a section perpendicular to the center line of the sleeve 1 is polygonal. By setting the protruding segment 101 to be a straight line segment and the recessed segment 102 to be an arc segment, the smoothness of the inner wall of the sleeve 1 is ensured on the one hand, and the blank allowance at the transition section between the small diameter 104 and the large diameter 103 is reduced on the other hand, making the outer circumferential surface contour of the sintered blank closer to a circle, further reducing the amount of grinding.

[0055] In one embodiment, a further combination Figure 5 As shown, the circumferential dimension of the shielding block 3 along the sleeve 1 is H, and the circumferential distance between two adjacent magnet structures 201 along the sleeve 1 is K. H and K satisfy the condition: 1 / 2 ≤ H / K ≤ 2 / 3. It should be noted that the shielding block 3 has a high permeability, causing magnetic field lines to tend to pass along the path of the shielding block, reducing diffusion into the surrounding space and thus reducing the number of magnetic field lines distributed in the surrounding space. If H / K is less than 1 / 2, the size of the shielding block 3 is insufficient, and the shielding effect is not significant or poor. If H / K is greater than 2 / 3, the size of the shielding block 3 is too large, and most of the magnetic field lines generated by the magnet structure 201 directly reach the shielding block 3, affecting the orientation of the magnetic ring inside the sleeve 1 by the applied magnetic field, thereby affecting the performance of the magnetic ring. Therefore, by setting the ratio H / K between the circumferential dimension H of the shielding block 3 along the sleeve 1 and the circumferential distance K between two adjacent magnetic structures 201 along the sleeve 1 to a value between 1 / 2 and 2 / 3, the shielding block 3 has a suitable size along the circumferential direction of the sleeve 1. This ensures that the shielding block 3 has a sufficiently effective shielding effect, thereby reducing the interference of the magnetic field between two adjacent magnetic structures 201 on the zero position and reducing magnetic ring cracking. It also avoids the shielding performance of the shielding block 3 being too strong, which could affect the magnetic properties of the magnetic ring. Preferably, H / K = 1 / 2, and the size of the shielding block 3 along the circumferential direction of the sleeve 1 is half the distance between two adjacent magnetic structures 201, at which point the magnetic ring performance is optimal.

[0056] In one embodiment, a further combination Figure 5As shown, the thickness of the shielding block 3 along the radial direction of the sleeve 1 is b, where the value of b is in the range of 3mm ≤ b ≤ 5mm. If b is less than 3mm, the thickness of the shielding block 3 is too small, the shielding effect is not obvious, and the magnetic field between two adjacent magnet structures 201 still has a large interference on the concave mold cavity; if b is greater than 5mm, the thickness of the shielding block 3 is too large, and most of the magnetic lines of force generated by the magnet structure 201 pass directly through the shielding block 3, resulting in an overly strong shielding effect that affects the orientation of the magnetic ring by the external magnetic field. Therefore, by setting the thickness b of the shielding block 3 along the radial direction of the sleeve 1 to be in the range of 3mm to 5mm, it is possible to ensure that the shielding block 3 has a sufficiently effective shielding effect, thereby reducing the interference of the magnetic field between two adjacent magnet structures 201 on the zero position and reducing the cracking of the magnetic ring, while also avoiding the shielding performance of the shielding block 3 being too strong and affecting the magnetic properties of the magnetic ring.

[0057] In one embodiment, a further combination Figure 5 As shown, the distance from the shielding block 3 to the outer circumferential surface of the sleeve 1 along the radial direction is 'a', where the value of 'a' ranges from 2mm to 4mm. It should be noted that 'a' is the vertical distance from the shielding block 3 to the outer circumferential surface of the sleeve 1 along the radial direction. If 'a' is less than 2mm, the shielding block 3 is too close to the sleeve 1, resulting in an overly strong shielding effect that affects the orientation of the magnetic ring by the applied magnetic field, thus impacting the performance of the magnetic ring. If 'a' is greater than 4mm, the shielding block 3 is too far from the sleeve 1, the shielding effect is not significant, and the magnetic field between two adjacent magnetic structures 201 still significantly interferes with the concave mold cavity. Therefore, by setting the distance 'a' of the shielding block 3 from the radial direction of the sleeve 1 to the outer circumferential surface of the sleeve 1 to be between 2 mm and 4 mm, the shielding block 3 can have a suitable shielding effect. This can both prevent the shielding performance of the shielding block 3 from being too strong and affecting the magnetic properties of the magnetic ring, and ensure that the shielding block 3 has a sufficiently effective shielding effect, thereby reducing the interference of the magnetic field between two adjacent magnetic structures 201 on the zero position, so as to reduce the cracking of the magnetic ring.

[0058] In one embodiment, the height of the shielding block 3 is equal to the height of the magnet structure 201. It should be noted that height refers to the height perpendicular to... Figure 1 The dimensions along the paper surface. By setting the height of the shielding block 3 to be relative to the height of the magnet structure 201, the shielding block 3 is ensured to have a shielding effect along the height direction of the magnet structure 201, thereby ensuring the shielding effect.

[0059] In one embodiment, a ring-shaped magnetic conductor 2 is fitted onto the outer side of the sleeve 1. Multiple grooves 202 are formed on the inner circumference of the magnetic conductor 2 to divide it into multiple magnetic structures 201. Winding assemblies 203 are disposed within the grooves 202. The inner circumference of the magnetic conductor 2 refers to the side of the magnetic conductor 2 that faces its centerline radially. By creating multiple grooves 202 on the inner circumference of the magnetic conductor 2, the side of the magnetic conductor 2 near the sleeve 1 is divided into multiple magnetic structures 201, achieving a circumferentially spaced distribution of multiple magnetic structures 201 around the sleeve 1. Furthermore, by setting a winding group 203 in the groove 202, when current flows through the winding group 203, the magnetic structure 201 is magnetized and generates magnetism, thereby applying a magnetic field to the concave mold cavity, achieving orientation of the magnetic ring in the concave mold cavity. The presence or absence of the magnetic field can be flexibly adjusted as needed, avoiding the magnetic field affecting the powder added to the concave mold cavity during the magnetic ring forming process. This is suitable for mass production and has high efficiency. Moreover, the multiple magnetic structures 201 are fixedly connected. By sleeved the magnetic conductor 2 on the outside of the sleeve 1, it is convenient to fix the multiple magnetic structures 201 to the sleeve 1 and ensure the stability of their positional relationship.

[0060] It should be noted that the magnetic conductor 2 is made of pure iron. The pure iron and the winding assembly together form the external magnetic field applied to the concave mold cavity, preferably a pulsed magnetic field, which can generate a strong magnetic field and achieve rapid magnetization, thus improving production efficiency. Further combining... Figure 1 As shown, taking an octagonal magnetic ring as an example, the structure of the magnetic conductor 2 and the polarity of the magnetic structure 201 after applying an external pulsed magnetic field are as follows. Figure 1 As shown, magnetic field lines 5 Figure 1 As shown by the dashed line with the arrow in the middle.

[0061] In other embodiments, the magnet structure 201 can be set as a neodymium iron boron magnet, with multiple neodymium iron boron magnets distributed circumferentially around the sleeve 1. In this case, there is no need to set the winding group 203, and the magnetic field can be directly applied to the concave mold cavity by the neodymium iron boron magnet, which can also achieve the orientation of the magnetic ring inside the concave mold cavity.

[0062] In one embodiment, the groove 202 is filled with glue. By filling the groove 202 with glue, the winding assembly 203 and the shielding block 3 in the groove 202 are radially fixed, thereby achieving relative fixation between the winding assembly 203 and the shielding block 3 and the magnetic conductor 2, thus improving the stability of the entire mold structure and ensuring the processing effect.

[0063] In one embodiment, the sleeve 1 is made of cemented carbide. Cemented carbide has high hardness and wear resistance, high strength and toughness, and good stability, thereby ensuring that the die maintains a precise cavity shape during the pressing of the magnetic ring, ensuring the consistency of the magnetic ring's shape, and has a long service life, reducing the cost of replacing the die, and also helping to improve the yield of the magnetic ring.

[0064] In one embodiment, the magnetic conductor 2 is made of pure iron. Pure iron has high magnetic permeability, which can effectively enhance the magnetic field strength and improve the utilization efficiency of the magnetic field.

[0065] In this embodiment, the multi-pole radial magnetic ring mold changes the direction of the pulsed magnetic field by adding a shielding block 3, thereby solving the influence of the magnetic field on the forming blank and reducing the occurrence of cracking. By setting the inner wall of the sleeve 1 to have an alternating concave-convex shape along the circumference of the sleeve 1, the cavity size is designed according to the shrinkage corresponding to the strong and weak magnetic positions of the blank. The concave mold cavity is designed with two sizes, with a larger size where the shrinkage is large and a smaller size where the shrinkage is small. This optimizes the structure of the concave mold cavity. After magnetic field orientation, the blank after shrinkage is closer to a circle after the magnetic ring is sintered. This makes the grinding amount at different positions along the circumference of the blank almost consistent, thereby reducing the grinding amount, improving production efficiency, and reducing production costs.

[0066] Although embodiments of the present 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 present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A multi-pole radial magnetic ring mold, characterized in that, include: The sleeve (1) has a cylindrical structure; Multiple magnet structures (201) are disposed on the outside of the sleeve (1), and the multiple magnet structures (201) are distributed circumferentially around the sleeve (1); Multiple shielding blocks (3) are disposed on the outside of the sleeve (1), the number of shielding blocks (3) is equal to the number of magnet structures (201), and each shielding block (3) is located between two adjacent magnet structures (201).

2. The multi-pole radial magnetic ring mold according to claim 1, characterized in that, The inner wall of the sleeve (1) has an alternating concave-convex shape along the circumference of the sleeve (1). The inner wall of the sleeve (1) includes protruding sections (101) and recessed sections (102). The number of recessed sections (102) is equal to the number of magnet structures (201) and they correspond one-to-one. The number of protruding sections (101) is equal to the number of recessed sections (102), and each protruding section (101) is connected between two adjacent recessed sections (102).

3. The multi-pole radial magnetic ring mold according to claim 2, characterized in that, The raised section (101) and the recessed section (102) have a smooth transition; Wherein, both the protruding segment (101) and the recessed segment (102) are arc segments, and the orthographic projection of the inner wall of the sleeve (1) on the cross section perpendicular to the center line of the sleeve (1) is plum blossom-shaped; or, the protruding segment (101) is a straight segment, the recessed segment (102) is an arc segment, and the orthographic projection of the inner wall of the sleeve (1) on the cross section perpendicular to the center line of the sleeve (1) is polygonal.

4. The multi-pole radial magnetic ring mold according to claim 1, characterized in that, The shielding block (3) has a circumferential dimension of H along the sleeve (1), and the distance between two adjacent magnet structures (201) along the circumferential direction of the sleeve (1) is K, wherein H and K satisfy the following condition: 1 / 2 ≤ H / K ≤ 2 / 3.

5. The multi-pole radial magnetic ring mold according to claim 1, characterized in that, The thickness of the shielding block (3) along the radial direction of the sleeve (1) is b, wherein the value of b is in the range of 3mm≤b≤5mm.

6. The multi-pole radial magnetic ring mold according to claim 1, characterized in that, The distance from the shielding block (3) to the outer circumference of the sleeve (1) along the radial direction of the sleeve (1) is a, where the value of a ranges from 2mm to 4mm.

7. The multi-pole radial magnetic ring mold according to claim 1, characterized in that, The height of the shielding block (3) is equal to the height of the magnet structure (201).

8. The multi-pole radial magnetic ring mold according to any one of claims 1 to 7, characterized in that, The outer side of the sleeve (1) is fitted with a ring-shaped magnetic conductor (2). The inner circumference of the magnetic conductor (2) is provided with a plurality of grooves (202) to divide the magnetic conductor (2) into a plurality of magnetic structures (201). A winding group (203) is provided in the groove (202).

9. The multi-pole radial magnetic ring mold according to claim 8, characterized in that, The groove (202) is filled with glue.

10. The multi-pole radial magnetic ring mold according to claim 8, characterized in that, The sleeve (1) is made of hard alloy; And / or, the magnetic conductor (2) is pure iron.

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