Vacuum hot pressing furnace for preparing neodymium iron boron magnet ring

Abstract

The utility model discloses a vacuum hot pressing furnace for preparing a neodymium iron boron magnetic ring, which belongs to the technical field of neodymium iron boron permanent magnet material processing, and comprises a furnace body and a heating power supply, the heating power supply is connected with an induction coil which penetrates through the furnace body and can move relative to the furnace body, and a first flexible connection sleeve is hermetically arranged between the heating power supply and the furnace body. The furnace body is further provided with a mold assembly, the mold assembly comprises a mold head and supports the heating power source, and the mold head is sleeved with the induction coil. According to the scheme, the induction coil can synchronously move along with the upper die head and the lower die head of the die assembly, and in order to prevent the part, penetrating through the furnace body, of the induction coil from damaging a vacuum system, the induction coil is sleeved with the first soft connecting sleeve in a sealed mode, so that normal movement of the induction coil can be guaranteed, and the vacuum system can be prevented from being damaged; and the induction coil is not easy to age, fatigue and burst, so that the service life is longer.

Description

Technical Field

[0001] The utility model relates to a vacuum hot pressing furnace, more specifically, it relates to a vacuum hot pressing furnace for preparing NdFeB magnetic rings. Background Art

[0002] Ring magnets are widely used in energy conversion devices such as servo motors and motors due to their special magnetic field distribution. At present, vacuum hot pressing furnaces for preparing NdFeB magnetic rings can be divided into resistance hot pressing furnaces and induction hot pressing furnaces according to their heating methods. Among them, induction hot pressing furnaces have a fast heating speed and low cost, and have broad market prospects. However, traditional induction hot pressing furnaces are usually only equipped with a single induction coil, and the induction coil cannot be moved, so the mold can only be heated in a fixed manner. In the process of preparing ring magnets using reverse extrusion molding technology, the upper punch needs to be heated to complete pressing and demolding.

[0003] For example: Chinese patent announcement number CN111261398B, announcement date July 30, 2021, the invention name is a hot pressing device, hot pressing system and preparation method for preparing NdFeB magnetic rings. The application discloses a hot pressing furnace for preparing NdFeB magnetic rings. The upper punch is provided with an upper punch induction coil on the outside, and the female die is provided with a female die induction coil on the outside. The upper punch induction coil can move with the movement of the upper punch, and the female die induction coil can move with the movement of the female die. The upper punch induction coil and the female die induction coil are connected to the heating power supply through a flexible connection. The upper punch induction coil can move with the movement of the upper punch, and the female die induction coil can move with the movement of the female die, which solves the problem in the prior art that the induction coil cannot move and can only heat the mold in a fixed manner. However, if this solution is used for a long time, there is a risk of fatigue and bursting at the copper braided belt and its interface in a vacuum state. Utility Model Content

[0004] The utility model overcomes the risk of bursting of the soft connection of the existing vacuum hot pressing furnace for preparing NdFeB magnetic rings under vacuum conditions; provides a vacuum hot pressing furnace for preparing NdFeB magnetic rings, and this solution can realize that the induction coil in the hot pressing furnace moves together with the die head, and the coil fatigue and bursting problems will not occur.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: a vacuum hot pressing furnace for preparing NdFeB magnetic rings, characterized in that it includes a furnace body and a heating power supply, the heating power supply is connected to an induction coil that passes through the furnace body and can move relative to the furnace body, a first flexible connecting sleeve is sealed between the heating power supply and the furnace body, the furnace body is also provided with a mold assembly, the mold assembly includes a die head and supports the heating power supply, and the induction coil is sleeved outside the die head. In this solution, the induction coil is used to heat the upper and lower dies in the mold assembly, and the induction coil passes through the furnace body and can move up and down relative to the furnace body, and the induction coil and the heating power supply are connected together, and the heating power supply is arranged on the mold assembly, so that the induction coil can move synchronously with the upper and lower dies of the mold assembly, and in order to prevent the portion of the induction coil that passes through the furnace body from damaging the vacuum system, a first flexible connecting sleeve is sealed outside the induction coil, and the first flexible connecting sleeve is arranged between the heating power supply and the furnace body, thereby ensuring the normal movement of the induction coil and ensuring that the vacuum system is not damaged, and the induction coil is not prone to fatigue and bursting problems, and has a longer service life.

[0006] Preferably, the mold assembly includes an upper mold assembly, which includes a press slide beam and an upper water-cooled ram. One end of the upper water-cooled ram is fixedly connected to the press slide beam, and the other end of the upper water-cooled ram is connected to an upper mold head assembly that penetrates the furnace body and is movable relative to the furnace body. The upper mold assembly is located at the top of the furnace body, and the press slide beam is used to mount the entire upper mold assembly structure. Driven by an external drive structure, the press slide beam can move up and down in the vertical direction, thereby driving the upper mold assembly to move up and down to complete the molding work.

[0007] Preferably, a second flexible connecting sleeve is sealed between the upper water-cooled ram and the furnace body, and is sleeved onto the exterior of the upper die assembly. Since the upper die assembly passes through the furnace body, a second flexible connecting sleeve is provided on the exterior of the upper die assembly to protect the vacuum system within the furnace body. This protects the vacuum system while also ensuring that the upper die assembly can move within the furnace body.

[0008] Preferably, the heating power supply includes a first heating power supply, and a hanger is provided on the press slide beam, with the first heating power supply mounted on the hanger. The first heating power supply is used to heat the die head of the upper die head assembly, and the hanger is used to mount the first heating power supply. The first heating power supply and the upper die head assembly are both provided on the press slide beam, thereby enabling the first heating power supply and the die head to move synchronously, ensuring the heating effect of the induction coil.

[0009] Preferably, an adjustable bracket is provided on the furnace body corresponding to the bottom of the hanger, and the adjustable bracket can limit the lowest position of the first heating power supply on the hanger, thereby limiting the lowest limit position of the induction coil to ensure normal molding and demolding operations.

[0010] Preferably, the mold assembly further comprises a lower mold assembly, which comprises a support plate and a lower die head assembly. A water-cooled ram is provided on one side of the support plate, and the lower die head assembly is provided on the other side of the support plate, with the lower die head assembly extending through the furnace body. The lower mold assembly is disposed at the bottom of the furnace body, the support plate being used to mount the lower mold assembly, the water-cooled ram being provided at the bottom of the support plate, and the lower die head assembly being provided at the top of the support plate and extending through the furnace body, thereby enabling normal molding of the lower mold assembly.

[0011] Preferably, the lower die assembly includes a female mold mounting plate located within the furnace body, a support column disposed between the female mold mounting plate and the support plate, and a third flexible connecting sleeve disposed between the furnace body and the support plate, sleeved on the outside of the support column. The female mold mounting plate is used to mount the female mold. The support column between the female mold mounting plate and the support plate passes through the furnace body and is capable of upward and downward movement relative to the furnace body, requiring the third flexible connecting sleeve to ensure sealing and movement at the penetration point.

[0012] Preferably, the heating power source includes a second heating power source, which is disposed on the support plate. The second heating power source is used to heat the female mold and the lower die head of the lower die assembly. The second heating power source and the lower die assembly are both disposed on the support plate so that the second heating power source and the lower die assembly can move synchronously, ensuring the heating effect of the induction coil.

[0013] Preferably, the hot pressing furnace further comprises a base, wherein a telescopic drive device is provided on the base, and a telescopic end of the telescopic drive device is connected to the support plate. The base is used to support the entire hot pressing furnace device, and the telescopic drive device can drive the support plate to move, thereby driving the movement of the lower die assembly.

[0014] Preferably, a column is provided between the base and the furnace body, and is used to fix the base and the furnace body structure, ensuring that the furnace body remains fixed when in operation.

[0015] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) the present solution can realize that the induction coil in the hot pressing furnace moves along with the die head, and there will be no problems of coil fatigue and bursting; (2) the heating effect of the induction coil is improved, ensuring the protection of the product during molding and demolding operations; (3) the extreme position of the induction coil in the upper mold assembly can be limited, which can prevent the upper and lower induction coils from interfering with each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is an overall schematic diagram of the utility model.

[0017] Figure 2 It is a cross-sectional schematic diagram of the present utility model.

[0018] Figure 3 Schematic diagram of the induction coil of the present invention.

[0019] Figure 4 It is a schematic diagram of the lower die head assembly of the present invention.

[0020] Figure 5 This is a schematic diagram of the upper die head of the utility model.

[0021] In the figure: 1. Furnace body, 2.1. First heating power supply, 2.2. Second heating power supply, 3.1. First induction coil, 3.2. Second induction coil, 4.1. First flexible connecting sleeve, 4.2. Second flexible connecting sleeve, 4.3. Third flexible connecting sleeve, 5.1. Upper die head, 5.2. Lower die head, 6. Press slide beam, 7.1. Upper water-cooled ram, 7.2. Lower water-cooled ram, 8. Hanger, 9. Adjustable bracket, 10. Support plate, 11. Female die mounting plate, 12. Support column, 13. Base, 14. Telescopic drive device, 15. Column, 16.1. Upper die metal ram, 16.2. Lower die metal ram, 17. Ring coil, 18. Female die, 19.1. First pad, 19.2. Second pad. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be further described below with reference to specific embodiments and in conjunction with the accompanying drawings.

[0023] Example 1: Figure 1 and Figure 2 A vacuum hot pressing furnace for preparing NdFeB magnetic rings is shown, comprising a furnace body 1 and a mold assembly, the mold assembly comprising an upper mold assembly and a lower mold assembly, the furnace body 1 as a whole is a cylindrical cavity structure, an upper mold assembly is provided at the upper part of the furnace body 1, and a lower mold assembly is provided at the lower part of the furnace body 1.

[0024] Specifically, the upper die assembly includes a press slide beam 6, an upper water-cooled ram 7.1 and an upper die assembly, and the upper die assembly includes an upper die metal ram 16.1 and an upper die 5.1. Figure 5The figure shows a schematic diagram of the structure of the upper die head 5.1; the press slide beam 6 is the installation structure of the entire upper die assembly, providing an installation position for each upper die assembly structure. The press slide beam 6 is arranged on the upper part of the furnace body 1 and maintains a certain distance from the furnace body 1. An upper water-cooled ram 7.1 is provided at the bottom of the press slide beam 6. The upper water-cooled ram 7.1 is fixedly connected to the bottom of the press slide beam 6. The lower part of the upper water-cooled ram 7.1 is connected to the upper die metal ram 16.1, and the lower part of the upper die metal ram 16.1 is connected to the upper die head 5.1. The upper die metal ram 16.1 passes through the upper part of the furnace body 1 and can generate relative movement on the furnace body 1 in the vertical direction. When the external power mechanism drives the press slide beam 6, the press slide beam 6 will generate up and down movement, thereby driving the upper die head assembly to move up and down inside the furnace body 1 to perform the molding work of the NdFeB magnetic ring.

[0025] The interior of the furnace body 1 is an environment with a certain degree of vacuum. In order to ensure that the portion where the upper die metal ram 16.1 passes through the furnace body 1 is not connected to the outside world, a second flexible connecting sleeve 4.2 is provided between the upper water-cooled ram 7.1 and the furnace body 1. The second flexible connecting sleeve 4.2 is provided on the outside of the upper die metal ram 16.1, and the two ends of the second flexible connecting sleeve 4.2 are respectively sealed with the bottom of the lower water-cooled ram 7.1 and the upper part of the furnace body 1. The second flexible connecting sleeve 4.2 has a telescopic or ductile property. When the upper water-cooled ram 7.1 moves downward and approaches the upper part of the furnace body 1, the second flexible connecting sleeve 4.2 will be compressed. When the upper water-cooled ram 7.1 moves upward and away from the upper part of the furnace body 1, the second flexible connecting sleeve 4.2 will be extended, thereby ensuring the normal movement of the upper die head assembly. Specifically, the second flexible connecting sleeve 4.1 can be a bellows or a hose made of other plastic materials, which can protect the vacuum system inside the furnace body 1 while ensuring the normal movement of the upper die head assembly.

[0026] A hanger 8 is also provided at the bottom of the press slide beam 6. The hanger 8 is a four-rod structure. The hangers are vertically arranged at the bottom of the press slide beam 6. The upper ends of the hangers are fixedly connected to the bottom of the press slide beam 6, and the lower ends of the hangers are L-shaped, which are used to support the first heating power supply 2.1. The first heating power supply 2.1 is arranged on the hanger 8 formed by the four hangers. A first induction coil 3.1 is provided at the bottom of the first heating power supply 2.1. The hanger 8 and the first heating power supply 2.1 are located outside the furnace body 1, and the first induction coil 3.1 passes through the upper position of the furnace body 1. One end of the first induction coil 3.1 is connected to the first heating power supply 2.1, and the other end of the first induction coil 3.1 is provided at the corresponding position of the upper die head 5.1. Specifically, Figure 1 or Figure 3As shown, since the upper die assembly and the first induction coil 3.1 are not aligned in the same vertical direction, the first induction coil 3.1 located inside the furnace body 1 needs to be bent into an L-shape so that the lower end of the first induction coil 3.1 is closer to the upper die 5.1. The portion of the first induction coil 3.1 adjacent to the upper die 5.1 is wound into a toroidal coil 17 and sleeved onto the exterior of the upper die 5.1, while the remaining portion of the first induction coil 3.1 is a straight section. When the first heating power source 2.1 is operating, the portion of the first induction coil 3.1 wound into the toroidal coil 17 performs heating. Since the hanger 8 (first heating power source 2.1) and the upper die assembly are both mounted on the press slide 6, when the press slide 6 moves up and down, the first heating coil 3.1 and the upper die 5.1 also move up and down synchronously, continuously heating the upper die 5.1 to the set hot pressing temperature, and then maintaining the temperature, thereby improving the molding efficiency and the molding effect of the NdFeB magnetic ring. Furthermore, since the entire first induction coil 3.1 remains stationary relative to the first heating power source 2.1 and the upper mold assembly during operation, it is less likely to suffer from fatigue, cracking, and other problems.

[0027] An adjustable bracket 9 is provided at the upper portion of the furnace body 1 and corresponding to the position of the hanger 8. Figure 1 or Figure 2 As shown, the adjustable bracket 9 is a convex column structure disposed on the upper portion of the furnace body 1. The adjustable bracket 9 is staggered with the four hanger rods of the hanger 8 to prevent interference between the two. The adjustable bracket 9 can block the downward movement of the first heating power source 2.1. Initially, the first heating power source 2.1 is located above the adjustable bracket 9 and maintains a certain distance from the adjustable bracket 9. When the press slide beam 6 moves downward, the first heating power source 2.1 also moves downward synchronously. However, when the upper die 5.1 and the lower die 5.2 come into contact and begin the molding operation, the first induction coil 3.1 no longer needs to continue to follow the upper die 5.1 downward. Instead, the first induction coil 3.1 must be stationary. Therefore, the first heating power source 2.1 abuts the adjustable bracket 9. The press slide beam 6 drives the upper die assembly to continue its downward molding operation, while the first induction coil 3.1 stops moving downward to avoid contact with the second induction coil 3.2.

[0028] It should be noted that the first induction coil 3.1 extends through the upper portion of the furnace body 1. Similarly, to protect the vacuum system within the furnace body 1, a first flexible connecting sleeve 4.1 is provided between the upper portion of the furnace body 1 and the first heating power source 2.1. The ends of the first flexible connecting sleeve 4.1 are sealedly connected to the bottom of the first heating power source 2.1 and the upper portion of the furnace body 1, respectively. The first flexible connecting sleeve 4.1 can be a bellows or a hose made of other plastic materials. While protecting the vacuum system within the furnace body 1, it also ensures the normal movement of the first induction coil 3.1.

[0029] Specifically, such as Figure 1 and Figure 4 As shown, the lower mold assembly includes a support plate 10 and a lower mold head assembly. The support plate 10 is arranged at the lower part of the furnace body 1 and maintains a certain distance from the furnace body 1. The support plate 10 is used to install and arrange the lower mold assembly. The lower mold head assembly includes a female mold 18, a lower mold head 5.2, and a female mold mounting plate 11. Four support columns 12 are arranged vertically on the support plate 10. One end of the four support columns 12 is located outside the furnace body 1 and is fixedly connected to the support plate 10. The other end of the four support columns 12 is located inside the furnace body 1. A female mold mounting plate 11 is arranged inside the furnace body 1. The female mold mounting plate 11 is arranged horizontally on the four support columns 12. A female mold 18 is arranged on the female mold mounting plate 11. A receiving cavity is provided inside the female mold 18, and the lower mold head 5.2 is provided inside the receiving cavity.

[0030] The support column 12 extends through the lower portion of the furnace body 1. Similarly, to protect the vacuum system within the furnace body 1, a third flexible connecting sleeve 4.3 is provided above the support plate 10 and below the furnace body 1. The third flexible connecting sleeve 4.3 is sealed against the bottom of the furnace body 1 and the upper portion of the support plate 10. The third flexible connecting sleeve 4.3 can be a bellows or a hose made of other plastic materials. While protecting the vacuum system within the furnace body 1, it also ensures the normal movement of the lower mold assembly.

[0031] A lower water-cooled ram 7.2 and a lower die metal ram 16.2 are also provided on the supporting plate 10. The lower water-cooled ram 7.2 is provided at the lower part of the supporting plate 10, and the lower die metal ram 17.2 is provided at the upper part of the supporting plate 10 and penetrates the furnace body 1 and extends into the interior of the furnace body 1. The part of the lower die metal ram 16.2 located inside the furnace body 1 is connected to the lower die head 5.2 and is used to complete the molding and demolding operations of the lower die head 5.2.

[0032] A second heating power source 2.2 is also provided on the supporting plate 10. The second heating power source 2.2 is fixed on the supporting plate 10. According to actual design requirements, the second heating power source 2.2 can be provided above the supporting plate 10 or below the supporting plate 10. In this embodiment, the second heating power source 2.2 is provided below the supporting plate 10. A second induction coil 3.2 is also provided on the second heating power source 2.2. The second induction coil 3.2 passes through the lower part of the furnace body 1. Figure 1 or Figure 3As shown, one end of the second induction coil 3.2 is connected to the second heating power supply 2.2, and the other end of the second induction coil 3.2 is arranged at the corresponding position of the lower die head 5.2. Since the lower die head assembly and the second induction coil 3.2 are not in the same vertical direction, the second induction coil 3.2 located inside the furnace body 1 needs to be bent into an L shape so that the upper end of the second induction coil 3.2 is close to the lower die head 5.2. The part of the second induction coil 3.2 close to the lower die head 5.2 is wound into an annular coil 17 and is sleeved on the outside of the female mold 18 and the lower die head 5.2, while the other parts of the second induction coil 3.2 are straight sections. When the second heating power supply 2.2 is working, the part of the second induction coil 3.2 wound into the annular ring 17 performs heating work. Because the second heating power source 2.2 and the lower mold assembly are both mounted on the support plate 10, when the support plate 10 moves, the second induction coil 3.2 moves synchronously with the lower die head 5.2 and the female mold 18, continuously heating the lower die head 5.2 to the set hot pressing temperature and then maintaining the temperature, thereby improving molding efficiency and the molding effect of the NdFeB magnetic ring. Furthermore, because the entire second induction coil 3.2 remains stationary relative to the second heating power source 2.2 and the lower mold assembly during operation, it is less susceptible to problems such as fatigue and cracking.

[0033] Similarly, the second induction coil 3.2 passes through the lower part of the furnace body 1. In order to protect the vacuum system inside the furnace body 1, a flexible connection sleeve is also required. The design is consistent with the above and will not be described in detail here.

[0034] A base 13 is also arranged below the support plate 10. The base 13 is used to support the entire hot pressing furnace device and install structures such as the drive device. Specifically, a telescopic drive device 14 is provided on the base 13. The telescopic drive device 14 is a pneumatic or oil cylinder structure. At least two telescopic drive devices 14 are arranged symmetrically at the bottom of the furnace body 1. The telescopic ends of the telescopic drive devices 14 are fixedly connected to the bottom of the support plate 10. When the telescopic drive devices 14 are in operation, they can drive the structures on the support plate 10 to move up and down, and also realize the up and down movement of the lower mold assembly inside the furnace body 1, cooperating with the upper mold assembly to complete the molding and demolding operations. There are also four columns 15 between the base 13 and the furnace body 1. The columns 15 are evenly distributed on the outside of the furnace body 1 and are arranged in a ring around the periphery of the telescopic drive device 14. The columns 15 are used to fix the base 13 and the furnace body 1 structure to ensure that the furnace body 1 remains fixed when in operation.

[0035] It should be noted that temperature measuring elements (not shown) are also installed on the upper die head 5.1, the lower die head 5.2, and the female mold 18. These temperature measuring elements are thermocouples that facilitate detection and control of the hot pressing temperature to ensure sample quality. A first pad 19.1 is installed between the upper die head 5.1 and the upper metal pressing head 16.1. The upper die head 5.1 is detachably connected to the upper metal pressing head 16.1 via the first pad 19.1. The first pad 19.1 not only adjusts the height position of the upper die head 5.1, but also makes the upper die head 5.1 removable, facilitating the replacement of molds of different specifications to accommodate the processing of samples of different sizes. Similarly, a second pad 19.2 is provided between the lower die head 5.1 and the lower die metal pressing head 16.2. The lower die head 5.2 is detachably connected to the lower die metal pressing head 16.2 through the second pad 19.2. On the one hand, the second pad 19.2 can adjust the height position of the lower die head 5.2. On the other hand, it also makes the lower die head 5.2 detachable, which is convenient for replacing molds of different specifications to adapt to the processing of samples of different sizes, thereby improving the versatility of the equipment.

Claims

1. A vacuum hot pressing furnace for preparing NdFeB magnetic rings, characterized in that: The utility model comprises a furnace body and a heating power supply, wherein the heating power supply is connected to one end of an induction coil which passes through the furnace body and can move up and down relative to the furnace body, and a first flexible connection sleeve is sealed between the heating power supply and the furnace body. A mold assembly is also provided on the furnace body, and the mold assembly includes a die head and supports the heating power supply. The other end of the induction coil is sleeved on the outside of the die head, and the induction coil is L-shaped. During operation, the induction coil is stationary relative to the heating power supply.

2. The vacuum hot pressing furnace for preparing NdFeB magnetic rings according to claim 1, characterized in that: The mold assembly includes an upper mold assembly, which includes a press slide beam and an upper water-cooled pressure head. One end of the upper water-cooled pressure head is fixedly connected to the press slide beam, and the other end of the upper water-cooled pressure head is connected to the upper mold head assembly that passes through the furnace body and can move relative to the furnace body.

3. The vacuum hot pressing furnace for preparing NdFeB magnetic rings according to claim 2, characterized in that: A second flexible connection sleeve is sealed between the upper water-cooled pressure head and the furnace body, and the second flexible connection sleeve is sleeved on the outside of the upper die head assembly.

4. A vacuum hot pressing furnace for preparing NdFeB magnetic rings according to claim 2 or 3, characterized in that: The heating power supply includes a first heating power supply. A hanger is further provided on the press slide beam, and the first heating power supply is provided on the hanger.

5. The vacuum hot pressing furnace for preparing NdFeB magnetic rings according to claim 4, characterized in that: An adjustable bracket is provided on the furnace body corresponding to the bottom of the hanger.

6. A vacuum hot pressing furnace for preparing NdFeB magnetic rings according to claim 1 or 2, characterized in that: The mold assembly also includes a lower mold assembly, which includes a supporting plate and a lower mold head assembly. A lower water-cooled pressure head is provided on one side of the supporting plate, and the lower mold head assembly is provided on the other side of the supporting plate. The lower mold head assembly passes through the furnace body.

7. The vacuum hot pressing furnace for preparing NdFeB magnetic rings according to claim 6, characterized in that: The lower die head assembly includes a female die mounting plate located inside the furnace body, a support column is provided between the female die mounting plate and the support plate, and a third flexible connection sleeve is sealed between the furnace body and the support plate and is sleeved on the outside of the support column.

8. The vacuum hot pressing furnace for preparing NdFeB magnetic rings according to claim 6, characterized in that: The heating power supply includes a second heating power supply, and the second heating power supply is arranged on the supporting plate.

9. The vacuum hot pressing furnace for preparing NdFeB magnetic rings according to claim 6, characterized in that: It also includes a base, on which a telescopic driving device is provided, and a telescopic end of the telescopic driving device is connected to the supporting plate.

10. The vacuum hot pressing furnace for preparing NdFeB magnetic rings according to claim 9, characterized in that: A column is provided between the base and the furnace body.

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