Neodymium iron boron magnet ring molding apparatus, neodymium iron boron magnet ring, and method for manufacturing the same

Abstract

The present invention provides a neodymium iron boron magnet ring molding apparatus, a neodymium iron boron magnet ring, and a method for manufacturing the same. [Solution] The neodymium iron boron magnet ring forming apparatus according to the present invention includes an upper punch 1, a die 2, a lower outer punch 3, and a lower inner punch 4. The neodymium iron boron magnet ring forming apparatus according to the present invention can complete multi-stage processes such as cold pressing, hot pressing, pre-deformation, and hot deformation extrusion, reduce process complexity, avoid repeated heating, and improve the performance of the neodymium iron boron magnet ring.

Description

[Technical Field]

[0001] The present invention relates to a neodymium iron boron magnet ring molding apparatus, and more particularly to a neodymium iron boron magnet ring and a method for manufacturing the same. [Background technology]

[0002] The manufacturing process for hot-deformable neodymium iron boron radioactive magnet rings exhibits near-net-shape characteristics and demonstrates significant advantages in the production of small, large-diameter, thin-walled, and high-performance ring-type magnets. Furthermore, the microstructure of hot-deformable neodymium iron boron radioactive magnet rings is composed of nanocrystalline grains, resulting in superior high-temperature magnetic properties. Currently, the manufacturing process for hot-deformable neodymium iron boron radioactive magnet rings mainly involves three steps: cold pressing, hot pressing, and hot deformation extrusion of rapidly solidified neodymium iron boron powder. Conventional technology typically requires separate devices and corresponding molds for each step, leading to process complexity and increased production costs. Moreover, in conventional manufacturing processes, after the cold-pressed blank of rapidly solidified neodymium iron boron magnetic powder undergoes the first heating process, an isotropic hot-pressed blank is obtained through a hot-pressing process. After cooling, it is then transferred to a hot deformation extrusion apparatus and reheated to a higher temperature to perform hot deformation extrusion on the isotropic hot-pressed blank. This necessitates repeated heating and temperature increases during the product manufacturing process, causing the crystal grains of the magnets to grow when exposed to high temperatures for extended periods, resulting in a deterioration of their magnetic properties.

[0003] CN113996791A discloses a method for manufacturing a high-performance hot-pressed neodymium iron boron magnet ring, which includes a cold pre-pressing step S1 in which neodymium iron boron magnetic powder is cold-press-formed to obtain a cold blank; a hot-pressing step S2 in which a solution prepared with composite lubricant A is uniformly applied to the surface of the cold blank, dried, and then placed in a forming device and hot-pressed to obtain a hot-pressed blank; and a hot deformation step S3 in which a solution prepared with composite lubricant B is uniformly applied to the surface of the hot-pressed blank, dried, and then placed in a forming device and hot-deformed to obtain a radioactive magnet ring. In this manufacturing method, although the magnetic properties can be improved to a certain extent by the combination of composite lubricant and manufacturing process, it is still necessary to press the material using cold pressing and hot-pressing / forming devices, respectively. [Overview of the Initiative]

[0004] In view of this, one object of the present invention is to provide a neodymium iron boron magnet ring forming apparatus that can complete multi-stage processes such as cold pressing, hot pressing, pre-deformation, and hot deformation extrusion, thereby reducing process complexity, avoiding repeated heating, and improving the performance of the neodymium iron boron magnet ring. Another object of the present invention is to provide a method for manufacturing a neodymium iron boron magnet ring. Yet another object of the present invention is to provide a neodymium iron boron magnet ring.

[0005] The above objectives will be achieved by the following technical proposals.

[0006] In one embodiment, the present invention relates to a neodymium iron boron magnet ring forming apparatus comprising an upper punch, a die, a lower outer punch, and a lower inner punch, The die is provided with a cavity for housing neodymium iron boron magnetic powder, at least a portion of the upper punch, at least a portion of the lower outer punch, and at least a portion of the lower inner punch, and the cavity of the die has an upper cavity opening and a lower cavity opening. The upper punch includes an upper punch head, the diameter of which matches the diameter of the die cavity, the upper punch head protrudes into the die cavity from the upper end opening of the cavity, and is configured to be vertically movable within the die cavity. The lower outer punch includes a lower outer punch head, the outer diameter of which is less than or equal to the diameter of the die, and the lower outer punch head protrudes from the lower end opening of the cavity into the cavity of the die and is provided to be able to move up and down within the cavity of the die. The lower inner punch includes a lower inner punch head, the diameter of which is less than or equal to the inner diameter of the lower outer punch head, and the lower inner punch head protrudes from the lower end opening of the cavity into the cavity of the die and is provided to be able to move up and down within the cavity of the die. The present invention provides a neodymium iron boron magnet ring forming apparatus.

[0007] According to the neodymium iron boron magnet ring forming apparatus of the present invention, preferably, the lower outer punch head includes a first body and a second body, the first body having a first body cavity, the first body protruding from the lower end opening of the die cavity and being provided to be vertically movable within the die cavity, and the second body having a second body cavity, the second body being drilled within the first body cavity and being vertically movable within the first body cavity.

[0008] According to the neodymium iron boron magnet ring forming apparatus of the present invention, preferably, the lower outer punch further includes a first connecting portion and a second connecting portion, wherein the first connecting portion is fitted onto the outer circumference of the bottom of the first body and is located below the bottom of the die, and the second connecting portion is fitted onto the outer circumference of the bottom of the second body and is located below the first connecting portion.

[0009] According to the neodymium iron boron magnet ring forming apparatus of the present invention, preferably, the lower inner punch further includes a third connecting portion, the lower inner punch head has a solid structure, the third connecting portion is connected vertically to the bottom of the lower inner punch head, the lower inner punch head is drilled in the second body cavity and is movable up and down within the second body cavity, and the third connecting portion is located below the second connecting portion.

[0010] According to the neodymium iron boron magnet ring forming apparatus of the present invention, preferably, the outer diameter of the first body is the same as the diameter of the die cavity, the diameter of the first body cavity is the same as the outer diameter of the second body, and the diameter of the second body cavity is the same as the diameter of the lower inner punch head.

[0011] According to the neodymium iron boron magnet ring forming apparatus of the present invention, preferably, the height of the second body is greater than the height of the first body, the length of the second connecting portion is less than the length of the first connecting portion, the height of the lower inner punch head is greater than the height of the second body, and the length of the third connecting portion is less than the length of the second connecting portion.

[0012] In another aspect, the present invention provides a method for manufacturing a neodymium iron boron magnet ring using the neodymium iron boron magnet ring molding apparatus, comprising the following steps. Step (1): Place the first body, the second body, and a portion of the lower inner punch head into the cavity of the die, such that the upper end surface of the first body and the upper end surface of the second body are flush, and there is a distance between the upper end surface of the lower inner punch head and the upper end surface of the first body, and place the neodymium iron boron billet into the space formed by these two, then move the upper punch head downward so that it contacts the upper end surface of the first body and the upper end surface of the second body, and move the lower inner punch head upward to press the neodymium iron boron billet, until the density of the neodymium iron boron billet is 3.5~5.5 g / cm³ 3 The process stops when it reaches a certain point to obtain a cold press blank. Step (2): Place the cold press blank at a temperature of 500-700°C, move the lower internal punch head upward, and press the cold press blank at a pressure of 50-350 MPa until the density is 7.0 g / cm³. 3 Continue pressing for 10-500 seconds to form the hot press blank. Step (3): The second body is moved downward to a position flush with the upper end surface of the lower inner punch head, heated to 700-800°C, and the second body and the lower inner punch head are moved upward simultaneously to press the hot press blank at a pressure of 100-300 MPa and a holding pressure of 10-500 s, thereby forming a first pre-deformed blank in the cavity of the first body. Step (4): The first pre-deformed blank is heated to 800-950°C and held for 30-500 seconds. The first body is moved downward to a position where it is flush with the upper end surface of the second body and the upper end surface of the lower inner punch head. While maintaining the first body, second body, and lower inner punch head in place, the upper punch head is moved downward to press the first pre-deformed blank at a pressure of 50-500 MPa and a holding pressure of 10-500 seconds, thereby forming a magnet ring precursor inside the die. Step (5): While keeping the second body and the lower inner punch head still, the upper punch head is moved downward to gradually press the magnet ring precursor at a pressure of 120-300 MPa and a pressing speed of 0.01-10 mm / s, while simultaneously pressing the lower edge of the magnet ring precursor with the first body, the pressure applied by the first body being less than 50 MPa. According to the manufacturing method of the present invention, preferably, step (1) further includes a step of applying a release agent, which is a uniform mixture of molybdenum disulfide powder and graphite powder in a mass ratio of 1:1 to 3, to the upper punch head, the first body, the side and bottom surfaces of the second body, and the cavity of the die.

[0013] According to the manufacturing method of the present invention, preferably, the upper punch head is quickly returned to escape from the cavity of the die, and the second main body and the lower inner punch head are moved downward to a position flush with the upper end surface of the first main body, and the first main body, the second main body and the lower inner punch head are simultaneously moved upward to be flush with the upper edge of the die, thereby completing the release of the sample and further including the step of obtaining a neodymium iron boron magnet ring.

[0014] In yet another aspect, the present invention provides a neodymium iron boron magnet ring obtained by the manufacturing method.

[0015] By adopting the neodymium iron boron magnet ring forming device according to the present invention, multi-stage processes such as cold pressing, hot pressing, preliminary deformation, and hot deformation extrusion can be completed, reducing the complexity of the process, avoiding repeated heating, realizing preliminary press deformation, and improving the performance of the neodymium iron boron magnet ring.

Brief Description of the Drawings

[0016] [Figure 1] FIG. 1 is a schematic structural diagram of a neodymium iron boron magnet ring forming device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a schematic diagram of the neodymium iron boron magnet ring forming device according to the present invention during the cold pressing process and the hot pressing process. [Figure 3] FIG. 3 is a schematic diagram of the neodymium iron boron magnet ring forming device according to the present invention during the first preliminary deformation process. [Figure 4] FIG. 4 is a schematic diagram of the neodymium iron boron magnet ring forming device according to the present invention during the second preliminary deformation process. [Figure 5] FIG. 5 is a schematic diagram of the neodymium iron boron magnet ring forming device according to the present invention during the extrusion process.

Explanation of Reference Numerals

[0017] 1-Upper punch, 11-Upper punch head, 2-Die, 3-Lower outer punch, 311-First body, 312-First connection part, 321-Second body, 322-Second connection part, 4-Lower inner punch, 41-Lower inner punch head, 42-Third connection part 100 - Hot-pressed blank, 200 - First pre-deformed blank, 300 - Magnet ring precursor, 400 - Hot-deformed neodymium iron boron magnet ring [Modes for carrying out the invention] The present invention will be further described below with reference to specific examples, but the scope of protection of the present invention is not limited thereto.

[0018] <Neodymium Iron-Boron Magnet Ring Forming Machine> The neodymium iron boron magnet ring forming apparatus according to the present invention includes an upper punch, a die, a lower outer punch, and a lower inner punch.

[0019] Dice The die according to the present invention is used to provide a place for forming a neodymium iron boron magnet ring, and is provided with a cavity in which neodymium iron boron magnetic powder, at least a portion of an upper punch, at least a portion of a lower outer punch, and at least a portion of a lower inner punch can be accommodated, and the cavity of the die has an upper cavity opening and a lower cavity opening.

[0020] Upper punch The upper punch is a solid structure located at the top of the die. The cross-section of the upper punch is generally "T" shaped. The upper punch is equipped with an upper punch head, the diameter of which is the same as the diameter of the die cavity. The upper punch head protrudes into the die cavity from the upper end opening of the cavity and is configured to be vertically movable within the die cavity. The upper punch is used to press the neodymium iron boron billet from above when pressing a sample, and exits through the upper end opening of the die cavity after pressing is complete.

[0021] Lower outside punch The aforementioned lower outer punch includes a lower outer punch head. The lower outer punch head is vertically movable within the die and is used to press the neodymium iron boron billet from below when pressing the sample, and exits through the upper opening of the die cavity after pressing is complete.

[0022] The lower outer punch may include a first body and a second body, the first body having a first body cavity and being provided to protrude from the lower end opening of the die cavity and to be able to move up and down within the die cavity, and the second body having a second body cavity and being drilled within the first body cavity and to be able to move up and down within the first body cavity.

[0023] The lower outer punch may further include a first connecting portion and a second connecting portion, the first connecting portion being fitted onto the outer circumference of the bottom of the first body and located below the bottom of the die, and the second connecting portion being fitted onto the outer circumference of the bottom of the second body and located below the first connecting portion. The first connecting portion and the second connecting portion can connect the first body and the second body to corresponding structures.

[0024] In the present invention, the outer diameter of the first body is the same as the diameter of the die cavity, and the diameter of the first body cavity is the same as the outer diameter of the second body.

[0025] In the present invention, the height of the second body is greater than the height of the first body, and the length of the second connecting portion is less than the length of the first connecting portion.

[0026] Lower inside punch The lower internal punch may include a lower internal punch head and a third connecting portion, both of which are provided as solid structures and connected vertically, and the cross-section of the lower internal punch is generally "T" shaped. The lower internal punch head is provided as a solid structure, the third connecting portion is connected vertically to the bottom of the lower internal punch head, the lower internal punch head is drilled in the second body cavity and is movable up and down within the second body cavity, and the third connecting portion is located below the second connecting portion.

[0027] In the present invention, the diameter of the lower inner punch head is the same as the diameter of the second body cavity.

[0028] In the present invention, the height of the lower internal punch head is greater than the height of the second main body, and the length of the third connecting portion is less than the length of the second connecting portion.

[0029] The diameter of the upper punch head may be 30 to 60 mm, preferably 33 to 55 mm, and more preferably 35 to 52 mm. The diameter of the die cavity may be 30 to 60 mm, preferably 33 to 55 mm, and more preferably 35 to 52 mm. In some embodiments, the diameter of the upper punch head is 38 mm, and the diameter of the die cavity is 38 mm. In some other embodiments, the diameter of the upper punch head is 50.8 mm, and the diameter of the die cavity is 50.8 mm.

[0030] The diameter of the first body cavity may be 25 to 50 mm, preferably 28 to 48 mm, and more preferably 30 to 45 mm. The outer diameter of the second body may be 25 to 50 mm, preferably 28 to 48 mm, and more preferably 30 to 45 mm. In some embodiments, the diameter of the first body cavity is 30.2 mm, and the outer diameter of the second body is 30.2 mm. In some other embodiments, the diameter of the first body cavity is 44.8 mm, and the outer diameter of the second body is 44.8 mm.

[0031] The diameter of the lower internal punch head may be 15 to 35 mm, preferably 16 to 32 mm, and more preferably 17 to 28 mm. The diameter of the second body cavity may be 15 to 35 mm, preferably 16 to 32 mm, and more preferably 17 to 28 mm. In some embodiments, the diameter of the lower internal punch head is 17 mm, and the diameter of the second body cavity is 17 mm. In some other embodiments, the diameter of the lower internal punch head is 27.8 mm, and the diameter of the second body cavity is 27.8 mm.

[0032] <Manufacturing method for neodymium iron-boron magnet rings> The neodymium iron boron magnet ring according to the present invention is manufactured by the molding apparatus described above and includes the following steps: cold pressing, hot pressing, first pre-deformation step, second pre-deformation step, and extrusion step. In some embodiments, a pre-treatment step and a demolding step are further included. This allows the steps to be completed in a single apparatus, which will be described in detail below.

[0033] Pre-processing step In the present invention, the entire chamber of the hot press machine is sealed and evacuated, then argon gas is filled in, and the inside of the chamber of the device is repeatedly cleaned so that the oxygen content in the gas inside the device is less than 50 ppm, preferably less than 30 ppm.

[0034] In the present invention, a release agent made by mixing molybdenum disulfide powder and graphite powder may be applied to the upper punch head, the side and bottom surfaces of the first body and the second body, as well as to the cavity of the die. The mass ratio of molybdenum disulfide powder to graphite powder may be 1:1 to 3, preferably 1:1 to 2, and more preferably 1:1.

[0035] Cold press step Cold pressing means pressing a billet without heating it.

[0036] The first body, the second body, and a portion of the lower inner punch head are placed in the cavity of the die. Here, the upper end surface of the first body and the upper end surface of the second body are flush, and there is a distance between the upper end surface of the lower inner punch head and the upper end surface of the first body. A neodymium iron boron billet is placed in the space formed by these two, and then the upper punch head is moved downward to a position where the upper end surface of the first body and the upper end surface of the second body are flush (i.e., in contact), and the lower inner punch head is moved upward to press the neodymium iron boron billet until the neodymium iron boron billet density is 3.5 to 5.5 g / cm³. 3 The process stops when it reaches a certain point to obtain a cold press blank.

[0037] In this step, the upper punch head is in contact with the upper end surfaces of the first and second bodies, and the upper end surface of the lower inner punch head is located below these three. As a result, the billet falls into the cavity of the second body, and the pressing takes place only within the cavity of the second body.

[0038] The neodymium iron boron billet may contain praseodymium, neodymium, iron, cobalt, gallium, and boron. Here, the total content of praseodymium and neodymium is preferably 25-32 wt%, more preferably 29-31 wt%, the iron content is preferably 60-65 wt%, more preferably 63-65 wt%, the cobalt content is preferably 2-6 wt%, more preferably 3.5-5.5 wt%, the gallium content is preferably 0.3-0.6 wt%, more preferably 0.4-0.55 wt%, and the boron content may be less than 1 wt%, preferably 0.8-0.96 wt%, more preferably 0.9-0.95 wt%.

[0039] The density of the cold-pressed blank is 3.5 to 5.5 g / cm³. 3 It may be, preferably 3.5 to 4.5 g / cm³ 3 More preferably 3.8 to 4.2 g / cm³ 3 That is the case.

[0040] Hot pressing step Place the cold press blank at a temperature of 500 - 700 °C, and move the lower inner punch head upward, and press the cold press blank at a pressure of 50 - 350 MPa for 10 - 500 s continuously until the density of the cold press blank reaches 7.0 g / cm 3 or more to form a hot press blank.

[0041] The hot pressing temperature may be 500 - 700 °C, preferably 550 - 650 °C, and more preferably 600 - 650 °C.

[0042] The hot pressing pressure may be 50 - 350 MPa, preferably 100 - 350 MPa, and more preferably 200 - 350 MPa.

[0043] The hot pressing time may be 10 - 500 s, preferably 20 - 50 s, and more preferably 25 - 35 s.

[0044] The density of the hot press blank may exceed 7.0 g / cm 3 and preferably exceed 7.3 g / cm 3 and more preferably exceed 7.5 g / cm 3 .

[0045] First preliminary deformation step Downwardly move the second body to a position flush with the upper end surface of the lower inner punch head, heat it to 700 - 800 °C, and simultaneously move the second body and the lower inner punch head upward to press the hot press blank at a pressure of 100 - 300 MPa, and hold the pressure for 10 - 500 s to form a first preliminary deformation blank in the cavity of the first body.

[0046] In this step, while maintaining the upper punch head and the first body not to move, move the second body downward to a position flush with the upper end surface of the lower inner punch head. Thereby, the hot press blank is pressed within the cavity of the first body.

[0047] The temperature of the first preliminary deformation may be 700 to 800°C, preferably 720 to 780°C, and more preferably 720 to 750°C.

[0048] The pressure for the first preliminary deformation may be 100 to 300 MPa, preferably 120 to 280 MPa, and more preferably 150 to 250 MPa.

[0049] The holding time may be 10 to 500 seconds, preferably 20 to 40 seconds, and more preferably 25 to 35 seconds.

[0050] Second preliminary deformation step The first pre-deformed blank is heated to 800-950°C and held for 30-500 seconds. The first body is then moved downward to a position where it is flush with the upper end surface of the second body and the upper end surface of the lower inner punch head. While maintaining the first body, second body, and lower inner punch head in place, the upper punch head is moved downward to press the first pre-deformed blank at a pressure of 50-500 MPa, and the pressure is held for 10-500 seconds to form a magnet ring precursor inside the die.

[0051] In this step, the first body is moved downward to a position where it is flush with the upper end surface of the second body and the upper end surface of the lower inner punch head. As a result, the first pre-deformed blank is pressed within the die cavity.

[0052] The temperature for the second preliminary deformation may be 800 to 950°C, preferably 800 to 900°C, and more preferably 820 to 850°C.

[0053] The incubation time may be 30 to 500 seconds, preferably 30 to 100 seconds, and more preferably 50 to 80 seconds.

[0054] The pressure for the second preliminary deformation may be 50 to 500 MPa, preferably 100 to 450 MPa, and more preferably 150 to 400 MPa.

[0055] The holding time may be 10 to 500 seconds, preferably 20 to 40 seconds, and more preferably 25 to 35 seconds.

[0056] In conventional technology, different processes are carried out using different devices, requiring the sample obtained in the previous process to be cooled, then transferred to the next device and heated again to the desired temperature. Such repeated cooling and reheating tends to degrade the magnetic properties of the magnet ring. In the present invention, the temperature rises gradually from the hot pressing step to the first pre-deformation step and the second pre-deformation step. Therefore, when moving from the previous process to the next, heating can be done directly, avoiding the need to repeat operations (heating → cooling → reheating), and improving the magnetic properties of the neodymium iron boron magnet ring.

[0057] Extrusion step While maintaining the second body and the lower inner punch head in place, the upper punch head is moved downward to gradually press the magnet ring precursor at a pressure of 120-300 MPa and a pressing speed of 0.01-10 mm / s. At the same time, the lower edge of the magnet ring precursor is pressed using the first body, with the pressure applied by the first body being less than 50 MPa.

[0058] In this step, the upper punch head presses the magnetic ring precursor downwards, while the first body simultaneously presses the lower edge of the magnetic ring precursor. This ensures that the first body moves passively downwards during the sample extrusion process.

[0059] The pressure applied by the upper punch head may be 120 to 300 MPa, preferably 150 to 250 MPa, and more preferably 150 to 200 MPa.

[0060] The pressing speed of the upper punch head may be 0.01 to 10 mm / s, preferably 0.05 to 5 mm / s, and more preferably 0.08 to 2 mm / s.

[0061] The pressure applied by the first body may be less than 50 MPa, preferably less than 10 MPa, and more preferably less than 5 MPa.

[0062] Release step The upper punch head is quickly returned to its original position to escape from the die cavity, the second body and the lower inner punch head are moved downward to a position flush with the upper end surface of the first body, and the first body, the second body, and the lower inner punch head are simultaneously moved upward to a position flush with the upper edge of the die to complete the demolding of the sample and obtain a neodymium iron boron magnet ring.

[0063] <Neodymium Iron Boron Magnet Ring> The neodymium iron boron magnet ring according to the present invention is manufactured by the method described above.

[0064] Example 1 As shown in Figure 1, the neodymium iron boron magnet ring forming apparatus of this embodiment includes an upper punch 1, a die 2, a lower outer punch 3, and a lower inner punch 4.

[0065] The die 2 is provided with a cavity for accommodating neodymium iron boron magnetic powder, at least a portion of the upper punch 1, at least a portion of the lower outer punch 3, and at least a portion of the lower inner punch 4. The cavity of the die 2 has an upper cavity opening and a lower cavity opening.

[0066] The upper punch 1 includes an upper punch head 11, the cross-section of the upper punch 1 is generally "T" shaped, and the upper punch head 11 is solid. The diameter of the upper punch head 11 is the same as the diameter of the cavity of the die 2. The upper punch head 11 can protrude into the cavity of the die 2 from the upper end opening of the cavity and is movable up and down within the cavity of the die 2.

[0067] The lower outer punch 3 includes a first body 311, a first connecting part 312, a second body 321, and a second connecting part 322.

[0068] The first body 311 includes a first body cavity. The first body 311 can protrude into the cavity of the die 2 from the lower end opening of the cavity of the die 2 and is movable up and down within the cavity. The first connecting portion 312 is fitted onto the outer circumference of the bottom of the first body 311. The first connecting portion 312 is located below the bottom of the die 2.

[0069] The second body 321 comprises a second body cavity. The second body 321 can protrude into the cavity of the die 2 from the lower end opening of the cavity of the die 2 and is movable up and down within the cavity. Specifically, the second body 321 is drilled into the first body cavity and is movable up and down within the first body cavity. The second connecting portion 322 is fitted onto the outer circumference of the bottom of the second body 321. The second connecting portion 322 is located below the first connecting portion 312. The outer diameter of the second body 321 matches the diameter of the first body cavity. The height of the second body 321 is greater than the height of the first body 311, and the length of the second connecting portion 322 is less than the length of the first connecting portion 312.

[0070] The lower internal punch 4 includes a lower internal punch head 41 and a third connecting portion 42. The third connecting portion 42 is connected perpendicularly to the bottom of the lower internal punch head 41. The cross-section of the lower internal punch 4 is generally "T" shaped. The lower internal punch head 41 is solid. The lower internal punch head 41 can protrude into the cavity of the die 2 from the lower end opening of the cavity of the die 2 and is vertically movable within the cavity of the die 2. The third connecting portion 42 is located below the second connecting portion 322. Specifically, the lower internal punch head 41 is drilled into the second body cavity. The diameter of the lower internal punch head 41 is the same as the diameter of the second body cavity. The height of the lower internal punch head 41 is greater than the height of the second body 321, and the length of the third connecting portion 42 is less than the length of the second connecting portion 322.

[0071] In this embodiment, the diameter of the upper punch head 11, the diameter of the cavity of the die 2, and the outer diameter of the first body 311 are all 50.8 mm, the diameter of the first body cavity and the outer diameter of the second body 321 are both 44.8 mm, and the diameter of the lower inner punch head 41 and the diameter of the second body cavity are both 27.8 mm.

[0072] Example 2 In this embodiment, the diameter of the upper punch head 11, the diameter of the cavity of the die 2, and the outer diameter of the first body 311 are all 38 mm, the diameter of the first body cavity and the outer diameter of the second body 321 are both 30.2 mm, the diameter of the lower inner punch head 41 and the diameter of the second body cavity are both 17 mm, and all other aspects are the same as in Embodiment 1.

[0073] Example 3 A neodymium iron boron magnet ring was manufactured using the apparatus of Example 1, and the composition of the neodymium iron boron billet was as follows.

[0074] Total mass of Pr and Nd (mass ratio of Pr to Nd is 25:75): 30.6 wt%, Fe: 62.98 wt%, Co: 5 wt%, Ga: 0.5 wt%, B: 0.92 wt%.

[0075] The following steps were included.

[0076] The entire chamber of the hot press machine was sealed and evacuated, then filled with argon gas, and the inside of the chamber was repeatedly cleaned until the oxygen content in the gas inside the device was less than 50 ppm.

[0077] As shown in Figures 1 and 2, a release agent made by uniformly mixing molybdenum disulfide powder and graphite powder in a 1:1 ratio was applied to the upper punch head 11, the side and bottom surfaces of the first body 311 and the second body 321, as well as to the cavity of the die 2. The first body 311, the second body 321, and a portion of the lower inner punch head 41 were placed inside the cavity of the die 2. Here, the upper end surface of the first body 311 and the upper end surface of the second body 321 were flush, and the upper end surface of the lower inner punch head 41 was lower than the upper end surfaces of the first body 311 and the second body 321. There was a distance between the upper end surface of the lower inner punch head 41 and the upper end surface of the first body 311, and a neodymium iron boron billet was placed in the space formed by these two surfaces. Next, the upper punch head 11 is moved downward to a position where the upper end surface of the first body 311 and the upper end surface of the second body 321 are flush (i.e., in contact), and the lower inner punch 4 is moved upward to press the neodymium iron boron billet, until the neodymium iron boron billet density reaches 4.0 g / cm³. 3 The process was stopped when it reached a certain point to obtain a cold press blank.

[0078] The cold press blank was placed at a temperature of 600°C, and the lower internal punch 4 was moved upward while pressing at a pressure of 200 MPa for 30 seconds, resulting in a density of 7.3 g / cm³ of the cold press blank. 3 The process stopped when it reached a certain point, forming the hot press blank 100.

[0079] As shown in Figures 2 and 3, the second body 321 was moved downward to a position where the upper end surface of the second body 321 and the upper end surface of the lower inner punch head 41 were flush, and heated to 720°C. The second body 321 and the lower inner punch head 41 were moved upward simultaneously to press the hot press blank 100 at a pressure of 200 MPa, and held for 30 seconds to form the first pre-deformed blank 200 in the first body cavity.

[0080] As shown in Figures 3 and 4, the first pre-deformed blank 200 was continued to be heated to 820°C and held for 60 seconds. The first body 311 was then moved downward to a position where its upper end surface was flush with the upper end surface of the second body 321 and the upper end surface of the lower inner punch head 41. While maintaining the first body 311, the second body 321, and the lower inner punch head 41 in place, the upper punch head 11 was moved downward to press the first pre-deformed blank 200 at a pressure of 150 MPa, and the pressure was held for 30 seconds to form a magnet ring precursor 300 inside the die 2.

[0081] As shown in Figures 4 and 5, the pressure applied by the first body 311 was kept below 5 MPa while maintaining the second body 321 and the lower inner punch head 41 in position. Next, the upper punch head 11 was moved downward to gradually press the magnet ring precursor 300. The pressure applied by the upper punch head 11 was 150 MPa, and the pressing speed was 0.1 mm / s. Because the pressure applied to the first body 311 was relatively small, the first body 311 moved downward during the extrusion process of the magnet ring precursor 300.

[0082] After the extrusion process is complete, the upper punch head 11 is quickly returned to its original position to escape from the cavity of the die 2, the second body 321 and the lower inner punch head 41 are moved downward to a position flush with the upper end surface of the first body 311, and the first body 311, the second body 321 and the lower inner punch head 41 are simultaneously moved upward to a position flush with the upper edge of the die 2 to complete the demolding of the sample and obtain a hot-deformed neodymium iron boron magnet ring 400.

[0083] Example 4 A neodymium iron boron magnet ring was manufactured using the apparatus of Example 2, and the composition of the neodymium iron boron billet was as follows.

[0084] Total mass of Pr and Nd (mass ratio of Pr to Nd is 25:75): 29.8 wt%, Fe: 64.83 wt%, Co: 4 wt%, Ga: 0.45 wt%, B: 0.92 wt%.

[0085] The following steps were included.

[0086] The entire chamber of the hot press machine was sealed and evacuated, then filled with argon gas, and the inside of the chamber was repeatedly cleaned until the oxygen content in the gas inside the device was less than 30 ppm.

[0087] As shown in Figures 1 and 2, a release agent made by uniformly mixing molybdenum disulfide powder and graphite powder in a 1:1 ratio was applied to the upper punch head 11, the side and bottom surfaces of the first body 311 and the second body 321, as well as the cavity of the die 2. The first body 311, the second body 321, and a portion of the lower inner punch head 41 were placed inside the cavity of the die 2. Here, the upper end surface of the first body 311 and the upper end surface of the second body 321 were flush, and the upper end surface of the lower inner punch head 41 was lower than the upper end surfaces of the first body 311 and the second body 321. There was a distance between the upper end surface of the lower inner punch head 41 and the upper end surface of the first body 311, and a neodymium iron boron billet was placed in the space formed by these two surfaces. Next, the upper punch head 11 is moved downward to a position where the upper end surface of the first body 311 and the upper end surface of the second body 321 are flush (i.e., in contact), and the lower inner punch 4 is moved upward to press the neodymium iron boron billet, until the neodymium iron boron billet density reaches 4.0 g / cm³. 3 The process was stopped when it reached a certain point to obtain a cold press blank.

[0088] The cold press blank was placed at a temperature of 650°C, and the lower internal punch 4 was moved upward while pressing at a pressure of 350 MPa for 30 seconds, resulting in a density of 7.5 g / cm³ of the cold press blank. 3 The process stopped when it reached a certain point, forming the hot press blank 100.

[0089] As shown in Figures 2 and 3, the second body 321 was moved downward to a position where the upper end surface of the second body 321 and the upper end surface of the lower inner punch head 41 were flush, and heated to 750°C. The second body 321 and the lower inner punch head 41 were moved upward simultaneously to press the hot press blank 100 at a pressure of 200 MPa, and held for 30 seconds to form the first pre-deformed blank 200 in the first body cavity.

[0090] As shown in Figures 3 and 4, the first pre-deformed blank 200 was continued to be heated to 850°C and held for 60 seconds. The first body 311 was then moved downward to a position where its upper end surface was flush with the upper end surface of the second body 321 and the upper end surface of the lower inner punch head 41. While maintaining the first body 311, the second body 321, and the lower inner punch head 41 in place, the upper punch head 11 was moved downward to press the first pre-deformed blank 200 at a pressure of 150 MPa, and the pressure was held for 30 seconds to form a magnet ring precursor 300 inside the die 2.

[0091] As shown in Figures 4 and 5, the pressure applied by the first body 311 was kept below 10 MPa while maintaining the second body 321 and the lower inner punch head 41 in place. Next, the upper punch head 11 was moved downward to gradually press the magnet ring precursor 300. The pressure applied by the upper punch head 11 was 200 MPa, and the pressing speed was 0.1 mm / s. Because the pressure applied to the first body 311 was relatively small, the first body 311 moved downward during the extrusion process of the magnet ring precursor 300.

[0092] After the extrusion process is complete, the upper punch head 11 is quickly returned to its original position to escape from the cavity of the die 2, the second body 321 and the lower inner punch head 41 are moved downward to a position flush with the upper end surface of the first body 311, and the first body 311, the second body 321 and the lower inner punch head 41 are simultaneously moved upward to a position flush with the upper edge of the die 2 to complete the demolding of the sample and obtain a hot-deformed neodymium iron boron magnet ring 400.

[0093] Comparative Example 1 Using the method of Example 1 of the prior art CN113996791A, a neodymium iron boron billet with the same composition as Example 3 of the present application was subjected to cold pressing, pre-pressing, hot pressing, and hot deformation steps to obtain a neodymium iron boron magnet ring.

[0094] Comparative Example 2 Using the method of Example 1 of the prior art CN113996791A, a neodymium iron boron billet with the same composition as Example 4 of the present application was subjected to cold pressing, pre-pressing, hot pressing, and hot deformation steps to obtain a neodymium iron boron magnet ring.

[0095] The hot-deformed neodymium iron boron magnet rings obtained in Examples 3 and 4 and Comparative Examples 1 and 2 were measured using the following method.

[0096] The object to be measured is cut into 2x2x2mm cube-shaped measurement samples using a wire electrical discharge cutter, and the residual magnetic flux density B of the magnetic material is measured using a vibrating sample magnetometer. r , Maximum energy product (BH) max , intrinsic coercive force H cj The magnetic properties of the materials were measured.

[0097] The results obtained are shown in Table 1.

[0098] TIFF2026087519000002.tif52170

[0099] The present invention is not limited to the embodiments described above, and any modifications, improvements, or substitutions that a person skilled in the art could conceive of without departing from the spirit of the invention are also included within the scope of the invention.

Claims

1. A neodymium iron boron magnet ring forming apparatus including an upper punch, a die, a lower outer punch, and a lower inner punch, The die is provided with a cavity for housing neodymium iron boron magnetic powder, at least a portion of the upper punch, at least a portion of the lower outer punch, and at least a portion of the lower inner punch, and the cavity of the die has an upper cavity opening and a lower cavity opening. The upper punch includes an upper punch head, the diameter of which matches the diameter of the die cavity, the upper punch head protrudes into the die cavity from the upper end opening of the cavity, and is configured to be vertically movable within the die cavity. The lower outer punch includes a lower outer punch head, the outer diameter of which is less than or equal to the diameter of the die, and the lower outer punch head protrudes from the lower end opening of the cavity and is provided to be able to move up and down within the cavity of the die. A neodymium iron boron magnet ring forming apparatus, wherein the lower inner punch includes a lower inner punch head, the diameter of the lower inner punch head being less than or equal to the inner diameter of the lower outer punch head, the lower inner punch head protrudes from the lower end opening of the cavity into the cavity of the die, and is provided to be able to move up and down within the cavity of the die.

2. The neodymium iron boron magnet ring forming apparatus according to claim 1, characterized in that the lower outer punch head includes a first body and a second body, the first body having a first body cavity, the first body protruding from the lower end opening of the die cavity and being provided to be vertically movable within the die cavity, and the second body having a second body cavity, the second body being drilled within the first body cavity and being vertically movable within the first body cavity.

3. The neodymium iron boron magnet ring forming apparatus according to claim 2, wherein the lower outer punch further includes a first connecting portion and a second connecting portion, the first connecting portion being fitted onto the outer circumference of the bottom of the first body and located below the bottom of the die, and the second connecting portion being fitted onto the outer circumference of the bottom of the second body and located below the first connecting portion.

4. The neodymium iron boron magnet ring forming apparatus according to claim 3, characterized in that the lower inner punch further includes a third connecting portion, the lower inner punch head has a solid structure, the third connecting portion is connected vertically to the bottom of the lower inner punch head, the lower inner punch head is drilled in the second body cavity and is movable up and down within the second body cavity, and the third connecting portion is located below the second connecting portion.

5. The neodymium iron boron magnet ring forming apparatus according to claim 4, characterized in that the outer diameter of the first body is the same as the diameter of the die cavity, the diameter of the first body cavity is the same as the outer diameter of the second body, and the diameter of the second body cavity is the same as the diameter of the lower inner punch head.

6. The neodymium iron boron magnet ring forming apparatus according to claim 5, characterized in that the height of the second body is greater than the height of the first body, the length of the second connecting portion is less than the length of the first connecting portion, the height of the lower inner punch head is greater than the height of the second body, and the length of the third connecting portion is less than the length of the second connecting portion.

7. The first body, the second body, and a portion of the lower inner punch head are placed in the cavity of the die, with the upper end surface of the first body and the upper end surface of the second body being flush, and a distance existing between the upper end surface of the lower inner punch head and the upper end surface of the first body. A neodymium iron boron billet is placed in the space formed by these two, and then the upper punch head is moved downward so as to contact the upper end surface of the first body and the upper end surface of the second body, and the lower inner punch head is moved upward to press the neodymium iron boron billet, until the density of the neodymium iron boron billet is 3.5 to 5.5 g / cm³. ３ Step (1) stopping when it reaches a certain point to obtain a cold press blank, The cold press blank is placed at a temperature of 500-700°C, and the lower internal punch head is moved upward to press the cold press blank at a pressure of 50-350 MPa until the density reaches 7.0 g / cm³. ３ Step (2) continues by pressing for 10 to 500 seconds to form a hot press blank, Step (3) involves moving the second body downward to a position where it is flush with the upper end surface of the lower inner punch head, heating it to 700-800°C, moving the second body and the lower inner punch head upward simultaneously, pressing the hot press blank at a pressure of 100-300 MPa and a holding pressure of 10-500 s to form a first pre-deformed blank in the cavity of the first body, Step (4) involves heating the first pre-deformed blank to 800-950°C, holding it at this temperature for 30-500 seconds, moving the first body downward to a position where it is flush with the upper end surface of the second body and the upper end surface of the lower inner punch head, and while maintaining the first body, second body, and lower inner punch head in place, moving the upper punch head downward to press the first pre-deformed blank at a pressure of 50-500 MPa and a holding pressure of 10-500 seconds, thereby forming a magnet ring precursor inside the die. A method for manufacturing a neodymium iron boron magnet ring using a neodymium iron boron magnet ring molding apparatus according to any one of claims 2 to 6, characterized by including step (5) of gradually pressing the magnet ring precursor at a pressure of 120 to 300 MPa and a pressing speed of 0.01 to 10 mm / s while maintaining the second body and the lower inner punch head in position, the upper punch head is moved downward, and at the same time, the lower edge of the magnet ring precursor is pressed using the first body, wherein the pressure applied by the first body is less than 50 MPa.

8. The manufacturing method according to claim 7, further comprising the step of applying a release agent, which is a uniform mixture of molybdenum disulfide powder and graphite powder in a mass ratio of 1:1 to 3, to the upper punch head, the first body, the side and bottom surfaces of the second body, and the cavity of the die, in step (1).

9. The manufacturing method according to claim 8, further comprising the steps of: quickly returning the upper punch head to its original position to release it from the die cavity; moving the second body and the lower inner punch head downward to a position flush with the upper end surface of the first body; and simultaneously moving the first body, the second body, and the lower inner punch head upward to a position flush with the upper edge of the die to complete the demolding of the sample and obtain a neodymium iron boron magnet ring.

10. The neodymium iron boron magnet ring is characterized in that it is obtained by the manufacturing method described in any one of claims 7 to 9.

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