Forming die and forming method of magnetic ring

Abstract

The invention discloses a forming mold and a forming method of a magnetic ring, the forming mold comprises a fixed mold, an annular containing cavity is defined in the fixed mold, and the two ends of the containing cavity in the first direction are open; the hot-pressing upper die is annular, at least part of the hot-pressing upper die is arranged in the containing cavity, and the hot-pressing upper die can move relative to the containing cavity in the first direction; the hot-pressing lower die is annular, at least part of the hot-pressing lower die is arranged in the containing cavity, the hot-pressing lower die and the hot-pressing upper die are arranged in a spaced mode in the first direction, the hot-pressing lower die can move relative to the containing cavity in the first direction, and the hot-pressing upper die and the hot-pressing lower die are suitable for being matched with each other to be used for die pressing of a to-be-die-pressed part. According to the forming die, unformed areas can be effectively reduced, so that the machining amount can be reduced, the material utilization rate can be increased, and the production cost can be reduced; the uniformity of hot pressing and thermal deformation can be improved, so that the product quality can be improved; and mold pressing in multiple modes can be achieved, and then the adaptability of the forming mold can be improved.

Description

Technical Field

[0001] The invention relates to the technical field of magnet manufacturing, in particular to a molding die and a molding method of a magnetic ring. Background Art

[0002] It is pointed out in the related technology that the current preparation process of hot-deformed permanent magnets is divided into three steps: the first step is to press the powder at room temperature to obtain a cold-pressed blank; the second step is to heat the cold-pressed blank to about 500℃-800℃, further densify the blank by hot pressing, and obtain a hot-pressed blank after cooling; the third step is to reheat the hot-pressed blank to 600℃-900℃, and orient the easy magnetization axis of the grains inside the magnet in the direction of pressure by hot deformation, so as to obtain an anisotropic magnet with higher remanence and magnetic energy product. The second and third steps are both in a relatively high temperature (500℃-900℃) environment, involving a large range of heating-cooling-heating-cooling, which easily leads to the rapid growth of the grains inside the magnet and reduces the magnetic properties of the magnet. At present, in order to solve this problem, a forming mold and forming method of hot pressing and hot deformation magnets are proposed, which realizes the purpose of completing the two processes of hot pressing and hot deformation by heating at one time, so that the hot deformation achieves a better effect. However, this method still has a large number of unformed areas, which need to be cut when used, with high processing costs and low material utilization. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention is to propose a molding die, which can effectively reduce the unmolded area, thereby reducing the processing amount, improving the material utilization rate, and reducing the production cost; at the same time, it can also improve the uniformity of hot pressing, thereby improving the quality of the product, and in addition, it can also realize multiple modes of molding, thereby improving the adaptability of the molding die.

[0004] The invention also provides a method for forming a magnetic ring.

[0005] According to the first aspect of the present invention, the molding die comprises: a fixed die, the interior of which defines an annular accommodating cavity, the two ends of the accommodating cavity being open in a first direction; a hot pressing upper die, the hot pressing upper die being formed in an annular shape, at least a portion of the hot pressing upper die being arranged in the accommodating cavity, and being movable relative to the accommodating cavity along the first direction; a hot pressing lower die, the hot pressing lower die being formed in an annular shape, at least a portion of the hot pressing lower die being arranged in the accommodating cavity and being spaced apart from the hot pressing upper die along the first direction, the hot pressing lower die being movable relative to the accommodating cavity along the first direction, and the hot pressing upper die and the hot pressing lower die being suitable for cooperating with each other for molding the molded part.

[0006] According to the molding die of the present invention, by providing an annular accommodating cavity and a hot pressing upper die and a hot pressing lower die, the finished product after molding can be limited to be formed into a ring shape, thereby effectively reducing the unmolded area, thereby reducing the processing amount, improving material utilization, and reducing production costs; at the same time, by allowing the hot pressing upper die and the hot pressing lower die to move along the first direction, the uniformity of hot pressing and thermal deformation can be improved, thereby improving the quality of the product, and at the same time, multiple modes of molding can be achieved, thereby improving the adaptability of the molding die.

[0007] According to some embodiments of the present invention, the hot pressing upper mold includes: a plurality of first movable molds, each of which is formed in a ring shape and is sequentially arranged along the radial direction of the first movable mold, each of the first movable molds can be independently moved along the first direction, and each of the first movable molds has a first molding surface suitable for molding with the hot pressing lower mold.

[0008] According to some embodiments of the present invention, the ratio of the areas of any two of the first molding surfaces is 1.0-4.0.

[0009] According to some embodiments of the present invention, the hot pressing upper mold further includes: a plurality of first driving members, the plurality of first driving members correspond one-to-one to the plurality of first movable molds, and the first driving members are used to drive the corresponding first movable molds to move along the first direction.

[0010] According to some embodiments of the present invention, the hot pressing lower mold includes: a plurality of second movable molds, each of which is formed in a ring shape and is sequentially arranged along the radial direction of the second movable mold, each of the second movable molds can be independently moved along the first direction, and each of the second movable molds has a second molding surface suitable for molding with the hot pressing upper mold.

[0011] According to some embodiments of the present invention, the area ratio of any two of the second molding surfaces is 1.0-4.0.

[0012] According to some embodiments of the present invention, the hot pressing lower mold further includes: a plurality of second driving members, the plurality of second driving members corresponding one-to-one to the plurality of second movable molds, and used to respectively drive each of the second movable molds to move along the first direction.

[0013] According to some embodiments of the present invention, the plurality of first movable molds include: a first upper movable mold and a second upper movable mold, and the second upper movable mold is sleeved on the radial outside of the first upper movable mold; the plurality of second movable molds include: a first lower movable mold and a second lower movable mold, and the second lower movable mold is sleeved on the radial outside of the first lower movable mold.

[0014] According to some embodiments of the present invention, in a projection plane perpendicular to the first direction, projections of the first upper movable mold and the first lower movable mold completely overlap, and projections of the second upper movable mold and the second lower movable mold completely overlap.

[0015] According to the molding method of a magnetic ring according to the second aspect of the present invention, the magnetic ring is prepared and molded by using the molding mold according to the first aspect of the present invention, the magnetic ring includes a plurality of ring parts connected in sequence along the radial direction, the plurality of ring parts are annular columns extending along the first direction, and the end faces of at least one end of at least two of the ring parts in the first direction are not flush, the molding method includes: step S1, placing the part to be molded in the accommodating cavity; step S2, hot pressing the part to be molded by the hot pressing upper mold and the hot pressing lower mold to obtain a hot pressed circular ring embryo; step S3, heat deforming the hot pressed circular ring embryo by the hot pressing upper mold and the hot pressing lower mold to obtain the magnetic ring.

[0016] According to the forming method of the magnetic ring of the present invention, by adopting the forming mold according to the first aspect of the present invention to prepare the forming, the unformed area can be effectively reduced, and then the processing amount can be reduced, so as to improve the material utilization rate.

[0017] According to some embodiments of the present invention, the hot pressing upper mold includes a plurality of first movable molds which are sequentially mounted, each of the first movable molds has a first molding surface, and the hot pressing lower mold includes a plurality of second movable molds which are sequentially mounted, each of the second movable molds has a second molding surface, and the step S2 includes: S21, making the first molding surfaces of the plurality of first movable molds flush, and making the second molding surfaces of the plurality of second movable molds flush; S22, the plurality of first movable molds and the plurality of second movable molds cooperate with each other to apply pressure to the molded part to obtain the hot pressed ring blank.

[0018] According to some embodiments of the present invention, the hot pressing upper mold includes: a plurality of first movable molds arranged radially inner and outer, the hot pressing lower mold includes: a plurality of second movable molds arranged radially inner and outer, and the step S3 includes: S31, driving a part of the plurality of first movable molds and / or a part of the plurality of second movable molds to move along the first direction to move away from the hot pressing ring blank; S32, driving the plurality of first movable molds and / or the plurality of second movable molds to extrude the hot pressing ring blank so that the hot pressing ring blank is deformed; S33, driving a part of the plurality of first movable molds and / or a part of the plurality of second movable molds to apply pressure to the deformed hot pressing ring blank to obtain the magnetic ring.

[0019] According to some embodiments of the present invention, the plurality of first movable molds include: a first upper movable mold and a second upper movable mold sleeved on the radial outer side of the first upper movable mold, and the plurality of second movable molds include: a first lower movable mold and a second lower movable mold sleeved on the radial outer side of the first lower movable mold, wherein, in a projection plane perpendicular to the first direction, the projections of the first upper movable mold and the first lower movable mold completely overlap, and the projections of the second upper movable mold and the second lower movable mold completely overlap, and the step S3 includes: S31, driving the second upper movable mold and / or the second lower movable mold to move along the first direction to move away from the hot pressed ring blank; S32, driving the first movable mold and / or the second movable mold to extrude the hot pressed ring blank so that the hot pressed ring blank is deformed; S33, driving the second upper movable mold and / or the second lower movable mold to apply pressure to the deformed hot pressed ring blank to obtain the magnetic ring.

[0020] According to some embodiments of the present invention, the first upper movable mold and the second upper movable mold both have a first molding surface, and the first lower movable mold and the second lower movable mold both have a second molding surface, and step S32 also includes: making the first molding surface of the first upper movable mold coplanar with the first molding surface of the second upper movable mold; or, making the second molding surface of the first lower movable mold coplanar with the second molding surface of the second lower movable mold; or, making the first molding surface of the first upper movable mold and the first molding surface of the second upper movable mold staggered in the first direction, and making the second molding surface of the first lower movable mold and the second molding surface of the second lower movable mold staggered in the first direction.

[0021] According to some embodiments of the present invention, the hot pressing upper mold includes a plurality of first movable molds, and the step S1 includes: S01, moving at least one of the plurality of first movable molds out of the accommodating cavity; S02, placing the molded part in the accommodating cavity; S03, moving the first movable mold back into the accommodating cavity.

[0022] According to some embodiments of the present invention, the part to be molded is a powder raw material or a magnet blank formed by cold pressing.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a schematic diagram of a molding die according to an embodiment of the present invention;

[0025] Figure 2 is a motion schematic diagram of step S1 of the forming mold according to an embodiment of the present invention;

[0026] Figure 3is a motion schematic diagram of step S2 of the forming mold according to an embodiment of the present invention;

[0027] Figure 4 is a motion schematic diagram of one example of step S3 of the forming mold according to an embodiment of the present invention;

[0028] Figure 5 is a motion schematic diagram of another example of step S3 of the forming mold according to an embodiment of the present invention;

[0029] Figure 6 is a motion diagram of yet another example of step S3 of the molding die according to an embodiment of the present invention.

[0030] Reference numerals:

[0031] 100. Forming mold;

[0032] 10. Fixed mold; 11. Accommodating cavity;

[0033] 20, hot pressing upper mold; 21, first movable mold; 211, first upper movable mold; 212, second upper movable mold;

[0034] 30, hot pressing lower mold; 31, second movable mold; 311, first lower movable mold; 312, second lower movable mold;

[0035] 200, part to be molded; 300, hot pressed ring blank; 400, magnetic ring. DETAILED DESCRIPTION

[0036] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.

[0037] Reference below Figure 1 A molding die 100 according to an embodiment of the first aspect of the present invention will be described.

[0038] like Figure 1 As shown, the molding die 100 according to the first embodiment of the present invention comprises: a fixed die 10, a hot pressing upper die 20 and a hot pressing lower die 30, wherein the fixed die 10 defines an annular accommodating cavity 11 inside, and the accommodating cavity 11 is oriented in a first direction (e.g. Figure 1The hot pressing upper mold 20 is formed into a ring shape, at least part of which is arranged in the accommodating cavity 11, and is movable along a first direction relative to the accommodating cavity 11; the hot pressing lower mold 30 is formed into a ring shape, at least part of which is arranged in the accommodating cavity 11 and is spaced apart from the hot pressing upper mold 20 along the first direction, and the hot pressing lower mold 30 is movable along the first direction relative to the accommodating cavity 11, and the hot pressing upper mold 20 and the hot pressing lower mold 30 are suitable for cooperating with each other for molding the molded part 200.

[0039] Among them, the fixed mold 10 is the basic structure of the molding mold 100, which mainly provides a holding space for the hot pressing upper mold 20, the hot pressing lower mold 30 and the molded part 200; the hot pressing upper mold 20 and the hot pressing lower mold 30 are mainly used to mold the molded part 200.

[0040] Specifically, the accommodating cavity 11 is configured to be open at both ends in the first direction, which is conducive to placing the molded part 200 into the accommodating cavity 11 and conveniently removing the finished product after molding. As a result, the clamping time and complexity in each molding cycle can be reduced, thereby improving production efficiency; at the same time, the open ends provide the necessary travel space for the hot pressing upper mold 20 and the hot pressing lower mold 30 to ensure their normal operation.

[0041] The hot pressing upper mold 20 and the hot pressing lower mold 30 are both arranged in the accommodating cavity 11 and can be moved along the first direction, so that pressure can be applied to the upper and lower sides of the molded part 200 at the same time, which not only helps to evenly distribute the pressure, but also can adjust the total pressure applied to the material as needed to improve the quality of the finished product. At the same time, the design also allows the hot pressing upper mold 20 and the hot pressing lower mold 30 to be controlled separately, thereby achieving a more complex pressure mode. The hot pressing upper mold 20, the hot pressing lower mold 30 and the accommodating cavity 11 are all arranged in an annular shape, which can limit the finished product formed into an annular shape after the mold 10 is pressed.

[0042] It should be noted that the forming mold 100 of this embodiment is generally used to produce the radiation orientation magnetic ring 400. In the current prior art, a round cake blank is generally prepared by hot pressing, and then the round cake blank is extruded and deformed to form a magnetic ring 400 with a U-shaped structure. This process will lead to an increase in the unformed area, thereby causing low material utilization. In this embodiment, since the accommodating cavity 11 and the hot pressing upper mold 20 and the hot pressing lower mold 30 are all formed in an annular shape, they can be limited to a circular ring shape during the hot pressing stage of producing the radiation orientation magnetic ring 400. Therefore, the unformed area can be effectively reduced, and the processing amount can be reduced, and the material utilization rate can be improved.

[0043] Among them, “at least part of the hot pressing upper mold 20 is arranged in the accommodating cavity 11” can be understood that the hot pressing upper mold 20 can be partially arranged in the accommodating cavity 11, or it can be arranged in the accommodating cavity 11. “At least part of the hot pressing lower mold 30 is arranged in the accommodating cavity 11” can be understood that the hot pressing lower mold 30 can be partially arranged in the accommodating cavity 11, or it can be arranged in the accommodating cavity 11.

[0044] When using the molding die 100, the molded part 200 (such as magnetic powder or other hot-pressable materials) is placed in the annular accommodating cavity 11 of the fixed mold 10. Then, the hot-pressing upper mold 20 and the hot-pressing lower mold 30 are driven to approach each other to apply uniform hot pressing to the material.

[0045] According to the molding die 100 of the embodiment of the present invention, by providing the annular accommodating cavity 11 and the hot pressing upper die 20 and the hot pressing lower die 30, the finished product after pressing by the die 10 can be limited to be formed into a ring shape, thereby effectively reducing the unformed area, thereby reducing the processing amount, improving material utilization, and reducing production costs; at the same time, by allowing the hot pressing upper die 20 and the hot pressing lower die 30 to move along the first direction, the uniformity of hot pressing and thermal deformation can be improved, thereby improving the quality of the product, and at the same time, multiple modes of molding can be realized, thereby improving the adaptability of the molding die 100.

[0046] According to some embodiments of the present invention, Figure 1 As shown, the hot pressing upper mold 20 includes: a plurality of first movable molds 21, which are all formed into an annular shape and are sequentially sleeved along the radial direction of the first movable mold 21, each of which can be independently moved along the first direction, and each of which has a first molding surface suitable for molding with the hot pressing lower mold 30. It can be understood that the number of the first movable molds 21 is multiple, for example, it can be two, three or more. Among them, each first movable mold 21 can cooperate with the hot pressing lower mold 30 to extrude the molded part 200 and can independently control its position and pressure. Therefore, the hot pressing and thermal deformation of the molded part 200 can be achieved by only using the mutual cooperation of the multiple first movable molds 21. At the same time, the pressure and temperature conditions can be more finely adjusted during the molding process, which helps to reduce defects and increase density, thereby improving product quality. At the same time, the position and pressure of each first movable mold 21 can be controlled according to demand, so that magnetic rings 400 with different specifications and performance requirements can be produced, thereby improving the applicability of the molding mold 100.

[0047] According to some embodiments of the present invention, the area ratio of the first molding surfaces of any two first movable molds 21 is 1.0-4.0. It should be explained that when the first movable mold 21 is away from the molded part 200, the first movable mold 21 and the accommodating cavity 11 jointly define a mold cavity to provide space for the deformation of the molded part 200. Therefore, when the molded part 200 is subjected to thermal deformation treatment, part of the first movable mold 21 is generally driven away from the molded part 200, and then the other part is pressurized to the molded part 200, so that part of it flows into the mold cavity, and the part that flows into the mold cavity is thermally deformed. Therefore, setting the area ratio of the first molding surfaces of any two first movable molds 21 to 1.0-4.0 can make the thermal deformation ratio of the magnet reach 50%-80%, and at the same time, the magnet can be better oriented, thereby improving the magnetic properties of the magnet.

[0048] For example, the ratio of the areas of the first molding surfaces of any two first movable dies 21 may be 1.0, 2.0, 3.0 or 4.0.

[0049] According to some embodiments of the present invention, the hot pressing upper mold 20 further includes: a plurality of first driving members, the plurality of first driving members correspond one-to-one to the plurality of first movable molds 21, and the first driving members are used to drive the corresponding first movable molds 21 to move along the first direction. Specifically, the driving member provides a driving force for the movement of the first movable mold 21. Among them, the plurality of first driving members correspond one-to-one to the plurality of first movable molds 21, so that the plurality of first movable molds 21 can be controlled individually, so that the magnetic rings 400 with different specifications and performance requirements can be produced, and the applicability of the molding mold 100 can be improved.

[0050] According to some embodiments of the present invention, Figure 1 As shown, the hot pressing lower mold 30 includes: a plurality of second movable molds 31, which are all formed into an annular shape and are sequentially sleeved along the radial direction of the second movable mold 31, each second movable mold 31 can be independently moved along the first direction, and each second movable mold 31 has a second molding surface suitable for molding with the hot pressing upper mold 20. It can be understood that the number of second movable molds 31 is multiple, for example, it can be two, three or more. Among them, each second movable mold 31 can cooperate with the hot pressing upper mold 20 to extrude the molded part 200 and can independently control its position and pressure. Therefore, the thermal deformation of the molded part 200 can be achieved by only using the mutual cooperation of multiple second movable molds 31. At the same time, the pressure and temperature conditions can be more finely adjusted during the molding process, which helps to reduce defects and increase density, thereby improving product quality. At the same time, the position and pressure of each second movable mold 31 can be controlled according to demand, so that magnetic rings 400 with different specifications and performance requirements can be produced, thereby improving the applicability of the molding mold 100.

[0051] According to some embodiments of the present invention, the area ratio of the second molding surfaces of any two second movable molds 31 is 1.0-4.0. It should be explained that when the second movable mold 31 is away from the molded part 200, the second movable mold 31 and the accommodating cavity 11 jointly define a mold cavity to provide space for the deformation of the molded part 200. Therefore, when the molded part 200 is subjected to thermal deformation treatment, part of the second movable mold 31 is generally driven away from the molded part 200, and then the other part is pressurized to make part of the molded part 200 flow into the mold cavity, and the part that flows into the mold cavity is thermally deformed. Therefore, setting the area ratio of the second molding surfaces of any two second movable molds 31 to 1.0-4.0 can make the thermal deformation ratio of the magnet reach 50%-80%, and at the same time, the magnet can be better oriented, thereby improving the magnetic properties of the magnet.

[0052] For example, the ratio of the areas of the second molding surfaces of any two second movable dies 31 may be 1.0, 2.0, 3.0 or 4.0.

[0053] According to some embodiments of the present invention, the hot pressing lower mold 30 further includes: a plurality of second driving members, which correspond one-to-one to the plurality of second movable molds 31, and are used to drive each second movable mold 31 to move along the first direction. Specifically, the driving member provides a driving force for the movement of the second movable mold 31. Among them, the plurality of second driving members correspond one-to-one to the plurality of second movable molds 31, so that the plurality of second movable molds 31 can be controlled individually, and the magnetic rings 400 with different specifications and performance requirements can be produced, so that the applicability of the molding mold 100 can be improved.

[0054] Optionally, the first driving member and the second driving member are both servo motors, wherein the servo motors have high stroke control accuracy and good controllability. Therefore, using the servo motors as power sources can further improve the molding quality of the magnets.

[0055] According to some embodiments of the present invention, Figure 1 As shown, the multiple first movable molds 21 include: a first upper movable mold 211 and a second upper movable mold 212, and the second upper movable mold 212 is sleeved on the radial outer side of the first upper movable mold 211; the multiple second movable molds 31 include: a first lower movable mold 311 and a second lower movable mold 312, and the second lower movable mold 312 is sleeved on the radial outer side of the first lower movable mold 311.

[0056] It can be understood that the number of the first movable molds 21 is two, namely the first upper movable mold 211 and the second upper movable mold 212, and the second upper movable mold 212 is sleeved on the radial outer side of the first upper movable mold 211, and the first upper movable mold 211 and the second upper movable mold 212 can be independently moved along the first direction; the number of the second movable molds 31 is also two, namely the first lower movable mold 311 and the second lower movable mold 312, and the second lower movable mold 312 is sleeved on the radial outer side of the first lower movable mold 311, and the first lower movable mold 311 and the second lower movable mold 312 can be independently moved along the first direction. In this way, the molding mold 100 of this embodiment can realize thermal deformation while simplifying the structure and operation complexity of the molding mold 100, thereby reducing the production cost of the molding mold 100 and improving the controllability of the molding mold 100. At the same time, since the first upper movable mold 211, the second upper movable mold 212, the first lower movable mold 311 and the second lower movable mold 312 can all be controlled individually, the molding mold 100 of this embodiment can realize various forms of extrusion (such as forward extrusion, reverse extrusion, and compound extrusion), thereby meeting the production needs of various types of magnets, thereby improving the applicability of the molding mold 100.

[0057] According to some embodiments of the present invention, in a projection plane perpendicular to the first direction, the projections of the first upper movable mold 211 and the first lower movable mold 311 completely overlap, and the projections of the second upper movable mold 212 and the second lower movable mold 312 completely overlap. It can be understood that the structures of the first upper movable mold 211 and the first lower movable mold 311 are completely identical, and the structures of the second upper movable mold 212 and the second lower movable mold 312 are completely identical, and in the first direction, the first upper movable mold 211 and the first lower movable mold 311 are completely opposite, and the second upper movable mold 212 and the second lower movable mold 312 are completely opposite, so that when the molding mold 100 of this embodiment is working, it can ensure that the first upper movable mold 211 and the first lower movable mold 311, the second upper movable mold 212 and the second lower movable mold 312 can be accurately aligned, and then can provide highly consistent pressure distribution and material flow control, thereby improving the consistency and product quality of the finished product.

[0058] Reference below Figure 2-Figure 6 The molding method of the magnetic ring 400 according to the second embodiment of the present invention is described.

[0059] According to the molding method of the magnetic ring 400 of the second aspect embodiment of the present invention, the magnetic ring 400 is prepared and molded using the molding mold 100 according to the first aspect embodiment of the present invention, and the magnetic ring 400 includes a plurality of ring portions connected in sequence along the radial direction, and the plurality of ring portions are all annular columns extending along the first direction, and the end faces of at least one end of at least two ring portions in the first direction are not flush.

[0060] Here, “the end surfaces of at least one end of at least two ring parts in the first direction are not flush” can be understood as that the end surfaces of at least one end or both ends of at least two ring parts in the first direction are not flush.

[0061] Molding methods include:

[0062] S1, placing the molded part 200 in the accommodating cavity 11;

[0063] S2, performing hot pressing treatment on the molded part 200 by means of the hot pressing upper mold 20 and the hot pressing lower mold 30 to obtain a hot pressed ring embryo 300;

[0064] S3, performing heat deformation treatment on the hot pressed circular ring blank 300 by using the hot pressed upper mold 20 and the hot pressed lower mold 30 to obtain the magnetic ring 400.

[0065] Among them, it should be noted that the hot pressing upper mold 20 and the hot pressing lower mold 30 perform hot pressing treatment on the molded part 200, and the hot pressing treatment can be performed by moving the hot pressing upper mold 20, or by moving the hot pressing lower mold 30, or by simultaneously moving the hot pressing upper mold 20 and the hot pressing lower mold 30 to perform hot pressing treatment on the molded part 200.

[0066] The hot pressing upper mold 20 and the hot pressing lower mold 30 perform thermal deformation treatment on the hot pressing ring blank 300. The hot pressing upper mold 20 can be moved to perform thermal deformation treatment on the molded part 200, or the hot pressing lower mold 30 can be moved to perform thermal deformation treatment on the molded part 200, or the hot pressing upper mold 20 and the hot pressing lower mold 30 can be moved simultaneously to perform thermal deformation treatment on the molded part 200.

[0067] According to the molding method of the magnetic ring 400 of the embodiment of the present invention, by adopting the molding mold 100 according to the first aspect of the present invention, the unmolded area can be effectively reduced, and the processing amount can be reduced, so as to improve the material utilization rate.

[0068] According to some embodiments of the present invention, the hot pressing upper mold 20 includes a plurality of first movable molds 21 which are sequentially sleeved, each of which has a first molding surface, and the hot pressing lower mold 30 includes a plurality of second movable molds 31 which are sequentially sleeved, each of which has a second molding surface, and step S2 includes:

[0069] S21, making the first molding surfaces of the plurality of first movable molds 21 flush with each other, and making the second molding surfaces of the plurality of second movable molds 31 flush with each other;

[0070] S22 , a plurality of first movable molds 21 and a plurality of second movable molds 31 cooperate with each other to apply pressure to the molded part 200 to obtain a hot-pressed annular embryo 300 .

[0071] It can be understood that step S2 is a hot pressing process, in which, before applying pressure to the molded part 200, the first molding surfaces of multiple first movable molds 21 and the second molding surfaces of multiple second movable molds 31 are made flush, which can improve the uniformity of pressure application and further improve the flatness of the outer surface of the hot-pressed ring blank 300 and the overall quality.

[0072] According to some embodiments of the present invention, the hot pressing upper mold 20 includes: a plurality of first movable molds 21 arranged radially inside and outside, and the hot pressing lower mold 30 includes: a plurality of second movable molds 31 arranged radially inside and outside, and step S3 includes:

[0073] S31, driving a part of the plurality of first movable molds 21 and / or a part of the plurality of second movable molds 31 to move along the first direction to move away from the hot-pressed annular blank 300; in this way, a deformation space can be provided for the subsequent deformation of the hot-pressed annular blank 300. It should be explained that in this step, only a part of the first movable mold 21 can be driven to move along the first direction, or a part of the second movable mold 31 can be driven to move along the first direction, or a part of the first movable mold 21 and a part of the plurality of second movable molds 31 can be driven to move along the first direction at the same time.

[0074] S32, driving the multiple first movable molds 21 and / or the multiple second movable molds 31 to extrude the hot-pressed circular ring embryo 300, so that the hot-pressed circular ring embryo 300 is deformed; it should be noted that this step is mainly to extrude the hot-pressed circular ring embryo 300 through the multiple first movable molds 21 and / or the multiple second movable molds 31, so that part of it enters the deformation space, and then deforms. It should be further noted that this step can only drive the multiple first movable molds 21 to move, or only drive the multiple second movable molds 31 to move, or can also drive the multiple first movable molds 21 and the multiple second movable molds 31 to move at the same time.

[0075] S33, driving a part of the multiple first movable molds 21 and / or a part of the multiple second movable molds 31 to apply pressure to the deformed hot-pressed circular ring embryo 300 to obtain a magnetic ring 400. In this way, the phenomenon of inner wall cracking can be improved, thereby improving the yield rate of the magnetic ring 400. It should be noted that in this step, only a part of the multiple first movable molds 21 can be driven to apply pressure to the deformed hot-pressed circular ring embryo 300, or only a part of the multiple second movable molds 31 can be driven to apply pressure to the deformed hot-pressed circular ring embryo 300, or a part of the multiple first movable molds 21 and a part of the multiple second movable molds 31 can be driven to apply pressure to the deformed hot-pressed circular ring embryo 300 at the same time.

[0076] It can be understood that step S3 is a thermal deformation process, wherein, in one example, the thermal deformation process is:

[0077] 1. Drive a portion of the plurality of first movable molds 21 to move along a first direction to move away from the hot-pressed annular embryo 300;

[0078] 2. driving another part of the plurality of first movable molds 21 or the plurality of second movable molds 31 to extrude the hot pressed annular embryo 300, so that the hot pressed annular embryo 300 is deformed;

[0079] 3. Drive a part of the plurality of first movable molds 21 to apply pressure to the deformed hot-pressed circular ring blank 300 to obtain a magnetic ring 400 .

[0080] In other embodiments, the thermal deformation process is:

[0081] 1. Drive a portion of the plurality of second movable molds 31 to move along a first direction to move away from the hot-pressed annular embryo 300;

[0082] 2. driving another part of the plurality of second movable molds 31 or the plurality of first movable molds 21 to extrude the hot pressed annular embryo 300, so that the hot pressed annular embryo 300 is deformed;

[0083] 3. Drive a part of the plurality of second movable molds 31 to apply pressure to the deformed hot-pressed circular ring blank 300 to obtain a magnetic ring 400 .

[0084] In some other embodiments, the thermal deformation process is:

[0085] 1. Drive a portion of the plurality of first movable molds 21 and a portion of the plurality of second movable molds 31 to move along a first direction to move away from the hot-pressed annular embryo 300;

[0086] 2. driving another part of the plurality of second movable molds 31 and another part of the plurality of first movable molds 21 to extrude the hot pressed annular embryo 300, so that the hot pressed annular embryo 300 is deformed;

[0087] 3. Drive a part of the plurality of first movable molds 21 and a part of the plurality of second movable molds 31 to apply pressure to the deformed hot-pressed circular ring blank 300 to obtain a magnetic ring 400 .

[0088] It should be further explained that the thermal deformation process in this embodiment includes but is not limited to the above-mentioned examples.

[0089] According to some embodiments of the present invention, the plurality of first movable molds 21 include: a first upper movable mold 211 and a second upper movable mold 212 sleeved on the radial outer side of the first upper movable mold 211, and the plurality of second movable molds 31 include: a first lower movable mold 311 and a second lower movable mold 312 sleeved on the radial outer side of the first lower movable mold 311, wherein, in a projection plane perpendicular to the first direction, the projections of the first upper movable mold 211 and the first lower movable mold 311 completely overlap, and the projections of the second upper movable mold 212 and the second lower movable mold 312 completely overlap, and step S3 includes:

[0090] S31, driving the second upper movable mold 212 and / or the second lower movable mold 312 to move along the first direction to move away from the hot pressed annular blank 300;

[0091] S32, driving the first movable mold 21 and / or the second movable mold 31 to extrude the hot pressed annular embryo 300, so that the hot pressed annular embryo 300 is deformed;

[0092] S33 , driving the second upper movable mold 212 and / or the second lower movable mold 312 to apply pressure to the deformed hot-pressed circular ring blank 300 to obtain the magnetic ring 400 .

[0093] It can be understood that step S3 is a thermal deformation process, wherein in the first specific example, the thermal deformation process is:

[0094] 1. Drive the second upper movable mold 212 to move along the first direction away from the hot-pressed annular blank 300, and at this time, a mold cavity is formed between the second upper movable mold 212, the first upper movable mold 211 and the accommodating cavity 11;

[0095] 2. Drive the first upper movable mold 211 in the first movable mold 21 to move along the first direction toward the hot pressed circular ring embryo 300 and squeeze the hot pressed circular ring embryo 300, so that the hot pressed circular ring embryo 300 is deformed and part of the hot pressed circular ring embryo 300 flows into the mold cavity;

[0096] 3. Drive the second upper movable mold 212 to move along the first direction toward the hot-pressed circular ring blank 300 and apply pressure to the deformed hot-pressed circular ring blank 300 to obtain the magnetic ring 400.

[0097] In the second specific example, the thermal deformation process is:

[0098] 1. Drive the second lower movable mold 312 to move along the first direction away from the hot-pressed annular blank 300, and at this time, a mold cavity is formed between the second lower movable mold 312, the first lower movable mold 311 and the accommodating cavity 11;

[0099] 2. Drive the first lower movable mold 311 to move along the first direction toward the hot pressed circular ring embryo 300 and squeeze the hot pressed circular ring embryo 300, so that the hot pressed circular ring embryo 300 is deformed and part of the hot pressed circular ring embryo 300 flows into the mold cavity;

[0100] 3. Drive the second lower movable mold 312 to move along the first direction toward the hot-pressed circular ring embryo 300 and apply pressure to the deformed hot-pressed circular ring embryo 300 to obtain the magnetic ring 400.

[0101] In the third specific example, the thermal deformation process is:

[0102] 1. Drive the second lower movable mold 312 to move along the first direction away from the hot-pressed annular blank 300, and at this time, a mold cavity is formed between the second lower movable mold 312, the first lower movable mold 311 and the accommodating cavity 11;

[0103] 2. driving the first upper movable mold 211 and the second upper movable mold 212 of the first movable mold 21 to move along the first direction toward the hot pressed annular embryo 300 and to extrude the hot pressed annular embryo 300, so that the hot pressed annular embryo 300 is deformed and a part of the hot pressed annular embryo 300 flows into the mold cavity;

[0104] 3. Drive the second lower movable mold 312 to move along the first direction toward the hot-pressed circular ring embryo 300 and apply pressure to the deformed hot-pressed circular ring embryo 300 to obtain the magnetic ring 400.

[0105] In the fourth specific example, the thermal deformation process is:

[0106] 1. Drive the second upper movable mold 212 and the second lower movable mold 312 to move along the first direction away from the hot pressed annular blank 300, and at this time, a mold cavity is formed between the second upper movable mold 212, the first upper movable mold 211, the second lower movable mold 312, the first lower movable mold 311 and the accommodating cavity 11;

[0107] 2. Drive the first upper movable mold 211 of the first movable mold 21 and the first lower movable mold 311 of the second movable mold 31 to move along the first direction toward the hot pressed annular embryo 300 and squeeze the hot pressed annular embryo 300, so that the hot pressed annular embryo 300 is deformed and part of the hot pressed annular embryo 300 flows into the mold cavity;

[0108] 3. Drive the second upper movable mold 212 and the second lower movable mold 312 to move along the first direction toward the hot-pressed circular ring embryo 300 and apply pressure to the deformed hot-pressed circular ring embryo 300 to obtain the magnetic ring 400.

[0109] It should be noted that, the pressure direction in the first specific example and the second specific example is different from the flow direction of the hot-pressed ring blank 300, that is, the first specific example and the second specific example are reverse extrusion examples; the pressure direction in the third specific example is the same as the flow direction of the hot-pressed ring blank 300, that is, the third specific example is a forward extrusion example; the pressure direction in the fourth specific example is both in the same direction and in a different direction from the flow direction of the hot-pressed ring blank 300, that is, the fourth specific example is a composite extrusion example; therefore, the molding die 100 of this embodiment can realize various forms of extrusion (such as forward extrusion, reverse extrusion, composite extrusion), and thus can meet the production requirements of various types of magnets, thereby improving the applicability of the molding die 100.

[0110] It should be further explained that the thermal deformation process in this embodiment includes but is not limited to the above-mentioned examples.

[0111] According to some embodiments of the present invention, the first upper movable mold 211 and the second upper movable mold 212 both have a first molding surface, and the first lower movable mold 311 and the second lower movable mold 312 both have a second molding surface, and step S32 also includes: making the first molding surface of the first upper movable mold 211 coplanar with the first molding surface of the second upper movable mold 212; or, making the second molding surface of the first lower movable mold 311 coplanar with the second molding surface of the second lower movable mold 312; or, making the first molding surface of the first upper movable mold 211 and the first molding surface of the second upper movable mold 212 staggered in the first direction, and making the second molding surface of the first lower movable mold 311 and the second molding surface of the second lower movable mold 312 staggered in the first direction.

[0112] It is understandable that, in some embodiments, step S32 also includes: making the first molding surface of the first upper movable mold 211 coplanar with the first molding surface of the second upper movable mold 212. It should be noted that the first molding surface of the first upper movable mold 211 and the first molding surface of the second upper movable mold 212 coplanar can play two roles. On the one hand, it can be used as a fixed end to realize the reverse extrusion function of the present molding device; on the other hand, it can be used as a movable end to realize the forward extrusion of the present molding device. Among them, when used as a fixed end, the present molding device realizes the thermal deformation process of the magnetic ring 400 by moving the first lower movable mold 311 and the second lower movable mold 312; when used as a movable end, the present molding device realizes the thermal deformation process by moving the first movable mold 21 and the second lower movable mold 312.

[0113] In other embodiments, step S32 further includes: making the second molding surface of the first lower movable mold 311 coplanar with the second molding surface of the second lower movable mold 312. It should be noted that the first molding surface of the first lower movable mold 311 and the first molding surface of the second lower movable mold 312 coplanar can play two roles. On the one hand, it can be used as a fixed end to realize the reverse extrusion function of the present molding device; on the other hand, it can be used as a movable end to realize the forward extrusion of the present molding device. Among them, when used as a fixed end, the present molding device realizes the thermal deformation process of the magnetic ring 400 by moving the first upper movable mold 211 and the second upper movable mold 212; when used as a movable end, the present molding device realizes the thermal deformation process by moving the second movable mold 31 and the second upper movable mold 212.

[0114] In some other embodiments, step S32 further includes: staggering the first molding surface of the first upper movable mold 211 and the first molding surface of the second upper movable mold 212 in the first direction, and staggering the second molding surface of the first lower movable mold 311 and the second molding surface of the second lower movable mold 312 in the first direction. It can be understood that in this embodiment, the first upper movable mold 211, the second upper movable mold 212, the first lower movable mold 311 and the second lower movable mold 312 are all moved.

[0115] According to some embodiments of the present invention, the hot pressing upper mold 20 includes a plurality of first movable molds 21, and step S1 includes:

[0116] S11, moving at least one of the plurality of first movable molds 21 out of the accommodating cavity 11;

[0117] S12, placing the molded part 200 in the accommodating cavity 11;

[0118] S13, moving the first movable mold 21 that has been removed back into the accommodating cavity 11.

[0119] It is understandable that step S11 can move one of the multiple first movable molds 21 out of the accommodating cavity 11, or can move multiple of the multiple first movable molds 21 out of the accommodating cavity 11, so that a channel for the molded part 200 to enter the accommodating cavity 11 can be provided.

[0120] According to some specific embodiments of the present invention, the method further includes: step S4, taking out the magnetic ring 400, step S4 includes:

[0121] S41, moving one of the hot pressing upper mold 20 and the hot pressing lower mold 30 out of the accommodating cavity 11;

[0122] S42 , driving the other one of the hot pressing upper mold 20 and the hot pressing lower mold 30 to move, so as to push the magnetic ring 400 out of the accommodating cavity 11 .

[0123] According to some embodiments of the present invention, the molded part 200 is a powder raw material or a magnet blank after cold pressing. It is understandable that in some embodiments, the molded part 200 is a powder raw material, wherein the powder raw material has high fluidity, and can be more conveniently placed in various specifications of the molding mold 100, so as to have higher applicability. In other specific embodiments, the molded part 200 is a magnet blank after cold pressing, wherein the magnet blank after cold pressing has been preliminarily pressed and processed, and thus, the magnet blank after cold pressing is used as the molded part 200, which can reduce the processing time of the finished magnetic ring 400, and thus can improve production efficiency.

[0124] The following will refer to Figure 1 A molding die 100 according to a specific embodiment of the first aspect of the present invention is described.

[0125] Referring to the figure, the molding mold 100 includes: a fixed mold 10, a hot pressing upper mold 20 and a hot pressing lower mold, wherein the fixed mold 10 defines an annular accommodating cavity 11 inside, and the two ends of the accommodating cavity 11 are open in the first direction; the hot pressing upper mold 20 is formed in a ring shape, at least part of the hot pressing upper mold 20 is arranged in the accommodating cavity 11, and is movable along the first direction relative to the accommodating cavity 11; the hot pressing lower mold 30 is formed in a ring shape, at least part of the hot pressing lower mold 30 is arranged in the accommodating cavity 11 and is spaced apart from the hot pressing upper mold 20 along the first direction, the hot pressing lower mold 30 is movable relative to the accommodating cavity 11 along the first direction, and the hot pressing upper mold 20 and the hot pressing lower mold 30 are suitable for cooperating with each other for molding the molded part 200.

[0126] The hot pressing upper mold 20 includes: a plurality of first movable molds 21 and a plurality of first driving members, wherein the plurality of first movable molds 21 are all formed in a ring shape and are sequentially arranged along the radial direction of the first movable mold 21, each first movable mold 21 can be independently moved along the first direction, and each first movable mold 21 has a first molding surface suitable for molding with the hot pressing lower mold 30; the plurality of first driving members correspond one-to-one to the plurality of first movable molds 21, and the first driving members are used to drive the corresponding first movable molds 21 to move along the first direction.

[0127] The hot pressing lower mold 30 includes: a plurality of second movable molds 31 and a plurality of second driving members, wherein the plurality of second movable molds 31 are all formed in a ring shape and are sequentially arranged along the radial direction of the second movable mold 31, each second movable mold 31 can be independently moved along the first direction, and each second movable mold 31 has a second molding surface suitable for molding with the hot pressing upper mold 20; the plurality of second driving members correspond one by one to the plurality of second movable molds 31, and are used to drive each second movable mold 31 to move along the first direction respectively.

[0128] The plurality of first movable molds 21 include: a first upper movable mold 211 and a second upper movable mold 212, the second upper movable mold 212 is sleeved on the radial outer side of the first upper movable mold 211, and the plurality of second movable molds 31 include: a first lower movable mold 311 and a second lower movable mold 312, the second lower movable mold 312 is sleeved on the radial outer side of the first lower movable mold 311, and in a projection plane perpendicular to the first direction, the projections of the first upper movable mold 211 and the first lower movable mold 311 completely overlap, and the projections of the second upper movable mold 212 and the second lower movable mold 312 completely overlap.

[0129] The following will refer to Figure 1-Figure 6 The forming method of the magnetic ring 400 of three specific embodiments of the second aspect of the present invention is described. Among them, the magnetic ring 400 is a radially oriented magnetic ring 400, and the magnetic ring 400 includes two ring parts connected in sequence along the radial direction, and the two ring parts are both annular columns extending along the first direction, and the end faces of at least one end of the two ring parts in the first direction are not flush. Further, the magnetic ring 400 is prepared and formed by using a forming mold 100.

[0130] Embodiment 1,

[0131] Molding methods include:

[0132] Step S1, moving the first upper movable mold 211 and the second upper movable mold 212 out of the accommodating cavity 11, placing the molded part 200 in the accommodating cavity 11, and moving the first upper movable mold 211 and the second upper movable mold 212 back into the accommodating cavity 11;

[0133] Step S2, aligning the first molding surface of the first upper movable mold 211 and the first transverse pressing surface of the second upper movable mold 212, aligning the first transverse pressing surfaces of the first lower movable mold 311 and the second lower movable mold 312, and then driving the first upper movable mold 211 and the second upper movable mold 212 to move toward the molded part 200, and performing hot pressing treatment on the molded part 200 to obtain a hot pressed annular blank 300;

[0134] Step S3, drive the second upper movable mold 212 to move along the first direction toward the direction away from the hot pressed ring embryo 300, so that a mold cavity is formed between the second upper movable mold 212, the first upper movable mold 211 and the accommodating cavity 11; drive the first upper movable mold 211 in the first movable mold 21 to move along the first direction toward the hot pressed ring embryo 300 and extrude the hot pressed ring embryo 300, so that the hot pressed ring embryo 300 is deformed, and part of the hot pressed ring embryo 300 flows into the mold cavity; drive the second upper movable mold 212 to move along the first direction toward the hot pressed ring embryo 300 and apply pressure to the deformed hot pressed ring embryo 300, thereby obtaining the magnetic ring 400.

[0135] Step S4, driving the second upper movable mold 212 away from the magnetic ring 400, then driving the first upper movable mold 211 and the second upper movable mold 212 to move out of the accommodating cavity 11, and then driving the second lower movable mold 312 to move toward the magnetic ring 400, and pushing the magnetic ring 400 out of the accommodating cavity 11.

[0136] Embodiment 2:

[0137] The method of this embodiment is substantially the same as that of the first embodiment, and the only difference is: step S3 and step S4.

[0138] Specifically, in step S3, first drive the second lower movable mold 312 to move along the first direction toward the direction away from the hot-pressed ring blank 300, so that a mold cavity is formed between the second lower movable mold 312 and the first lower movable mold 311 and the accommodating cavity 11; then drive the first upper movable mold 211 and the second upper movable mold 212 of the first movable mold 21 to be flush and move along the first direction toward the hot-pressed ring blank 300 and extrude the hot-pressed ring blank 300, so that the hot-pressed ring blank 300 is deformed, and part of the hot-pressed ring blank 300 flows into the mold cavity; finally, drive the second lower movable mold 312 to move along the first direction toward the hot-pressed ring blank 300 and apply pressure to the deformed hot-pressed ring blank 300, thereby obtaining the magnetic ring 400.

[0139] Step S4 , driving the first upper movable mold 211 and the second upper movable mold 212 away from the magnetic ring 400 and moving out of the accommodating cavity 11 , and then driving the second lower movable mold 312 to move toward the magnetic ring 400 and push the magnetic ring 400 out of the accommodating cavity 11 .

[0140] Embodiment 3,

[0141] The method of this embodiment is substantially the same as that of the first embodiment, and the only difference is: step S3 and step S4.

[0142] Specifically, step S3 drives the second upper movable mold 212 and the second lower movable mold 312 to move along the first direction toward the direction away from the hot pressed ring blank 300, so that a mold cavity is formed between the second upper movable mold 212, the first upper movable mold 211, the second lower movable mold 312 and the first lower movable mold 311 and the accommodating cavity 11; then drives the first upper movable mold 211 of the first movable mold 21 and the first lower movable mold 311 of the second movable mold 31 to move along the first direction toward the hot pressed ring blank 300 and extrude the hot pressed ring blank 300, so that the hot pressed ring blank 300 is deformed, and part of the hot pressed ring blank 300 flows into the mold cavity; finally, drives the second upper movable mold 212 and the second lower movable mold 312 to move along the first direction toward the hot pressed ring blank 300 and applies pressure to the deformed hot pressed ring blank 300, thereby obtaining the magnetic ring 400.

[0143] Step S4, drive the second upper movable mold 212 and the second lower movable mold 312 away from the magnetic ring 400, then drive the first upper movable mold 211 and the second upper movable mold 212 to move out of the accommodating cavity 11, and then drive the second lower movable mold 312 to move toward the magnetic ring 400, and push the magnetic ring 400 out of the accommodating cavity 11.

[0144] A comparative example 1 is briefly described below, and this comparative example 1 is used as a comparative example with the above-mentioned embodiment 1, embodiment 2 and embodiment 3 of the present invention.

[0145] Among them, comparative example 1 uses the mold and method in the specific implementation manner of patent number CN111009408A to form a hot-pressed and hot-deformed magnet, and the magnet formed by this method is U-shaped.

[0146] Specifically, the special mold of comparative example 1 includes: an outer mold, an inner mold, a main pressure plate, a pressure control plate, and a bottom plate; wherein, the outer mold and the inner mold are both hollow cylinders with openings at both ends, which are vertically arranged on the bottom plate, and the inner mold is arranged in the outer mold and coaxial with the outer mold; the main pressure plate is a circular plate whose size matches the inner mold. When in use, the main pressure plate covers the material in the inner mold to apply pressure to the material; the pressure control plate is a circular ring plate, whose inner diameter is equal to the outer diameter of the inner mold, and whose outer diameter is equal to the inner diameter of the outer mold. When in use, the pressure control plate covers the material contained between the outer mold and the inner mold, and is used to apply pressure to the material when necessary.

[0147] Experiments were conducted on Examples 1 to 3 and Comparative Example 1.

[0148] The experimental process is as follows:

[0149] 1. The molds and methods of the above-mentioned embodiment 1 and comparative example 1 are used to prepare 400 samples of hot-deformed magnetic rings with an outer diameter of 30 mm and an inner diameter of 24 mm and an outer diameter of 120 mm and an inner diameter of 99 mm, respectively. The experimental raw material formula is commercial MQU-F rapid quenching magnetic powder (NdFeB magnetic powder). The pressure, temperature, time, formula and other conditions during molding are exactly the same. The experimental conditions are shown in Table 1 below:

[0150] Table 1

[0151] Hot pressing temperature Hot Press Pressure Hot pressing rate Heat Deflection Temperature Thermal deformation pressure Thermal deformation rate 700℃ 400MPa 0.8mm / s 800℃ 200MPa 0.2mm / s

[0152] 2. To measure the thermal deformation of the blank, it is necessary to cut part of the cross-sectional area. The measurement results are shown in Table 2 below:

[0153] Table 2

[0154] Example Outer diameter / mm Inner diameter / mm <![CDATA[Cross-sectional area of the part to be cut / mm 2 > Comparative Example 1 30 24 706.5 Embodiment 1 30 24 505.5 Comparative Example 1 120 99 11304 Embodiment 1 120 99 4803.4

[0155] The above experimental results show that, compared with comparative example 1, using comparative example 1 of embodiment 1 of the present application can save processing allowance, thereby improving material utilization and reducing production costs.

[0156] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0157] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0158] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, an electrical connection, or a communication; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0159] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0160] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A molding die (100), characterized in that: include: A fixed mold (10), wherein an annular accommodating cavity (11) is defined inside the fixed mold (10), and the accommodating cavity (11) is open at both ends in a first direction; a hot pressing upper mold (20), the hot pressing upper mold (20) being formed in a ring shape, at least a portion of the hot pressing upper mold (20) being arranged in the accommodating cavity (11) and being movable relative to the accommodating cavity (11) along the first direction; A hot pressing lower die (30), the hot pressing lower die (30) is formed into a ring shape, at least a portion of the hot pressing lower die (30) is arranged in the accommodating cavity (11) and is spaced apart from the hot pressing upper die (20) along a first direction, the hot pressing lower die (30) is movable relative to the accommodating cavity (11) along the first direction, and the hot pressing upper die (20) and the hot pressing lower die (30) are suitable for cooperating with each other for molding a molded part (200).

2. The molding die (100) according to claim 1, characterized in that: The hot pressing upper mold (20) comprises: a plurality of first movable molds (21), each of which is formed into a ring shape and is sequentially arranged along the radial direction of the first movable mold (21), each of which can move independently along the first direction, and each of which has a first molding surface suitable for molding with the hot pressing lower mold (30).

3. The molding die (100) according to claim 2, characterized in that: The ratio of the areas of the first molding surfaces of any two of the first movable molds (21) is 1.0-4.

0.

4. The molding die (100) according to claim 2, characterized in that: The hot pressing upper mold (20) further comprises: a plurality of first driving members, the plurality of first driving members corresponding one-to-one to the plurality of first movable molds (21), the first driving members being used to drive the corresponding first movable molds (21) to move along the first direction.

5. The molding die (100) according to claim 2, characterized in that: The hot pressing lower mold (30) comprises: a plurality of second movable molds (31), each of which is formed into a ring shape and is sequentially arranged along the radial direction of the second movable mold (31), each of which can move independently along the first direction, and each of which has a second molding surface suitable for molding with the hot pressing upper mold (20).

6. The molding die (100) according to claim 5, characterized in that: The area ratio of the second molding surfaces of any two of the second movable molds (31) is 1.0-4.

0.

7. The molding die (100) according to claim 5, characterized in that: The hot pressing lower mold (30) further comprises: a plurality of second driving members, the plurality of second driving members corresponding one-to-one to the plurality of second movable molds (31), and used to respectively drive each of the second movable molds (31) to move along the first direction.

8. The molding die (100) according to claim 5, characterized in that: The plurality of first movable molds (21) include: a first upper movable mold (211) and a second upper movable mold (212), wherein the second upper movable mold (212) is sleeved on the radially outer side of the first upper movable mold (211). The plurality of second movable dies (31) include: a first lower movable die (311) and a second lower movable die (312), wherein the second lower movable die (312) is sleeved on the radially outer side of the first lower movable die (311).

9. The molding die (100) according to claim 8, characterized in that: In a projection plane perpendicular to the first direction, the projections of the first upper movable mold (211) and the first lower movable mold (311) completely overlap, and the projections of the second upper movable mold (212) and the second lower movable mold (312) completely overlap.

10. A method for forming a magnetic ring (400), wherein the magnetic ring (400) is formed by using a forming mold (100) according to any one of claims 1 to 9, wherein the magnetic ring (400) comprises a plurality of ring portions sequentially connected in a radial direction, wherein the plurality of ring portions are all annular columns extending in the first direction, and the end surfaces of at least one end of at least two of the ring portions in the first direction are not flush, characterized in that: The molding method comprises: Step S1, placing the molded part (200) in the accommodating cavity (11); Step S2, performing hot pressing treatment on the molded part (200) by using the hot pressing upper mold (20) and the hot pressing lower mold (30) to obtain a hot pressed annular embryo (300); Step S3, performing heat deformation treatment on the hot-pressed circular ring blank (300) by means of the hot-pressing upper mold (20) and the hot-pressing lower mold (30) to obtain the magnetic ring (400).

11. The method for forming a magnetic ring (400) according to claim 10, characterized in that: The hot pressing upper mold (20) comprises a plurality of first movable molds (21) which are sequentially sleeved, each of the first movable molds (21) having a first molding surface, and the hot pressing lower mold (30) comprises a plurality of second movable molds (31) which are sequentially sleeved, each of the second movable molds (31) having a second molding surface. The step S2 comprises: S21, making the first molding surfaces of the plurality of first movable molds (21) flush, and making the second molding surfaces of the plurality of second movable molds (31) flush; S22, a plurality of the first movable molds (21) and a plurality of the second movable molds (31) cooperate with each other to apply pressure to the molded part (200) to obtain the hot-pressed annular blank (300).

12. The method for forming a magnetic ring (400) according to claim 10, characterized in that: The hot pressing upper mold (20) comprises: a plurality of first movable molds (21) arranged radially inside and outside, and the hot pressing lower mold (30) comprises: a plurality of second movable molds (31) arranged radially inside and outside, The step S3 comprises: S31, driving a portion of the plurality of first movable molds (21) and / or a portion of the plurality of second movable molds (31) to move along a first direction to move away from the hot-pressed annular embryo (300); S32, driving the plurality of first movable dies (21) and / or the plurality of second movable dies (31) to extrude the hot pressed circular ring embryo (300), so that the hot pressed circular ring embryo (300) is deformed; S33, driving a portion of the plurality of first movable dies (21) and / or a portion of the plurality of second movable dies (31) to apply pressure to the deformed hot-pressed circular ring blank (300) to obtain the magnetic ring (400).

13. The method for forming a magnetic ring (400) according to claim 12, characterized in that: The plurality of first movable molds (21) include: a first upper movable mold (211) and a second upper movable mold (212) sleeved on the radial outer side of the first upper movable mold (211); the plurality of second movable molds (31) include: a first lower movable mold (311) and a second lower movable mold (312) sleeved on the radial outer side of the first lower movable mold (311); wherein, in a projection plane perpendicular to the first direction, the projections of the first upper movable mold (211) and the first lower movable mold (311) completely overlap, and the projections of the second upper movable mold (212) and the second lower movable mold (312) completely overlap, The step S3 comprises: S31, driving the second upper movable mold (212) and / or the second lower movable mold (312) to move along a first direction to move away from the hot-pressed annular embryo (300); S32, driving the first movable mold (21) and / or the second movable mold (31) to extrude the hot pressed circular ring embryo (300), so that the hot pressed circular ring embryo (300) is deformed; S33, driving the second upper movable mold (212) and / or the second lower movable mold (312) to apply pressure to the deformed hot-pressed circular ring blank (300) to obtain the magnetic ring (400).

14. The method for forming a magnetic ring (400) according to claim 13, characterized in that: The first upper movable mold (211) and the second upper movable mold (212) both have a first molding surface, and the first lower movable mold (311) and the second lower movable mold (312) both have a second molding surface. Step S32 also includes: The first molding surface of the first upper movable mold (211) and the first molding surface of the second upper movable mold (212) are made coplanar; or, The second molding surface of the first lower movable mold (311) and the second molding surface of the second lower movable mold (312) are made coplanar; or, The first molding surface of the first upper movable mold (211) and the first molding surface of the second upper movable mold (212) are staggered in the first direction, and the second molding surface of the first lower movable mold (311) and the second molding surface of the second lower movable mold (312) are staggered in the first direction.

15. The method for forming a magnetic ring (400) according to claim 10, characterized in that: The hot pressing upper mold (20) comprises a plurality of first movable molds (21), and the step S1 comprises: S11, moving at least one of the plurality of first movable molds (21) out of the accommodating cavity (11); S12, placing the molded part (200) in the accommodating cavity (11); S13, moving the first movable mold (21) that has been moved out back into the accommodating cavity (11).

16. The method for forming a magnetic ring (400) according to claim 10, characterized in that: The part to be molded (200) is a powder raw material or a magnet blank formed by cold pressing.

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