A MIM neodymium iron boron screening mixer

Abstract

This invention relates to the field of NdFeB internal mixing technology and discloses a MIM NdFeB sieving internal mixer, including a mixing cabinet with a mixing chamber and a feeding chamber. An additive cylinder and an active metal cylinder are installed in the feeding chamber, and a feeding channel is provided inside the feeding chamber, located below the additive and active metal cylinders and inclined towards the mixing chamber. A vacuum feeding device is provided on one side of the mixing cabinet, and a feeding space is provided below the mixing chamber, connected to the mixing chamber. A vacuum feeding channel is provided between the vacuum feeding device and the feeding space. The mixed material is transferred to the vacuum feeding device through the vacuum feeding channel. By pre-loading the additive into the additive cylinder and adding the active metal into the active metal cylinder of the device, the sealing and continuity of the addition environment are maintained, improving the internal mixing efficiency of NdFeB permanent magnets and reducing the oxidation waste rate of NdFeB powder.

Description

Technical Field

[0001] This invention relates to the field of NdFeB internal mixing technology, and particularly to a MIM NdFeB screening internal mixer. Background Technology

[0002] Neodymium iron boron (NdFeB) permanent magnets are a key component of many high-tech products, widely used in electric vehicles, wind turbines, consumer electronics, robotics, and other high-tech fields. They play a vital role in driving the transition from fossil fuels to renewable energy and in the miniaturization of electronic devices.

[0003] Traditional manufacturing methods include bonded NdFeB, sintered NdFeB, and hot-pressed / hot-deformed NdFeB. These methods involve long manufacturing processes and complex preparation techniques, and it is difficult to shape them into complex, small, and precise parts. Furthermore, the machining process results in a significant waste of NdFeB magnets, which limits their application range.

[0004] Therefore, MIN technology is used for manufacturing. MIM technology is a new near-net-shape forming technology for metal parts, which introduces modern plastic injection molding technology into the field of powder metallurgy. It combines the advantages of powder metallurgy and plastic injection molding, and can break through the limitations of traditional metal powder molding processes in terms of product shape, enabling the mass production and high-efficiency forming of metal parts with complex shapes.

[0005] Because NdFeB powder is easily oxidized, the oxygen content needs to be strictly controlled during the mixing process. At the same time, the method and amount of adding mixing aids (such as mixed solvents) also determine the final performance of MIM NdFeB products.

[0006] Current atmosphere-protected internal mixers are equipped with independent mixing chambers that can be vacuumed and purged with inert gas. They also contain oxygen content sensors to monitor the oxygen content within the mixing chamber and control the atmosphere during powder refining. However, because MIM (neodymium iron boron) magnetic powder is very fine, it requires pre-coating before the refining process. Therefore, the MIM magnetic powder to be refined often exhibits varying degrees of agglomeration and poor dispersibility, which inevitably affects the mixing and uniformity of additives during the refining process. Furthermore, current atmosphere-protected internal mixers still require manual pre-loading of the required powders and additives before vacuuming and purging with inert gas to remove oxygen, significantly reducing production efficiency and product stability.

[0007] For example, patent CN201621393834.4 discloses a new type of atmosphere-protected titanium alloy internal mixer, which can evacuate and protect the mixing chamber and mixing cavity with inert gas. However, the feeding method still requires manual feeding operation, and the feeding system cannot be operated continuously, which makes it difficult to better disperse fine metal powder.

[0008] For example, patent CN202123446554.9 discloses a side-feeding atmosphere-protected internal mixer. A feeding port is provided on the sealed cover, and a hand-operated port is provided on the side of the sealed cover. The operator can manually remove the feeding package and feed the material by reaching into the sealed cover, without affecting the internal sealing performance. However, the entire operation still requires manual operation, and the powder and additives need to be weighed and placed into the sealed cover before inert gas oxygen removal treatment, making it difficult to achieve good continuity in production.

[0009] Therefore, it is necessary to improve the MIM neodymium iron boron internal mixer to maintain good sealing and continuity during production, thereby improving the forming efficiency of neodymium iron boron permanent magnets and reducing the oxidation waste rate of neodymium iron boron powder. Summary of the Invention

[0010] The main objective of this invention is to propose a NdFeB sieving internal mixer, which aims to provide a NdFeB atmosphere-protected internal mixer with controllable powder sieving, feeding, and discharging functions.

[0011] To achieve the above objectives, this invention proposes a MIM neodymium iron boron screening mixer, comprising a mixing cabinet, a mixing chamber and a feeding chamber inside the mixing cabinet, an additive cylinder and an active metal cylinder on the feeding chamber, a feeding channel inside the feeding chamber located below the additive cylinder and the active metal cylinder, the feeding channel being inclined toward the mixing chamber, a vacuum feeding device on one side of the mixing cabinet, a feeding space below the mixing chamber connected to the mixing chamber, a vacuum feeding channel between the vacuum feeding device and the feeding space, and the mixed material being transferred to the vacuum feeding device through the vacuum feeding channel.

[0012] Specifically, the active metal cylinder includes a cylinder body, which has a receiving cavity for containing the active metal and a discharge port for discharging the active metal. The cylinder body is connected to the feeding chamber through the discharge port, and an oxygen venting pipe is provided at the discharge port.

[0013] Specifically, the oxygen venting pipe includes a first pipe and a second pipe, which are arranged side by side and are both connected to the receiving cavity. Both the first pipe and the second pipe are equipped with control valves, and the first pipe or the second pipe is connected to an external inert gas pipe.

[0014] Specifically, the active metal cylinder also includes a sieving device and a weighing device, which are located in the feeding chamber and connected to the discharge port from the upper right to the lower right.

[0015] Specifically, the powder screening device includes a powder screening motor and a powder screening screen. The powder screening screen is located directly below the discharge port. A connecting groove is provided on the powder screening screen, and the powder screening motor is connected to the powder screening screen through the connecting groove.

[0016] Specifically, the weighing device includes a material scoop block located directly below the powder sieve. The material scoop block is provided with a material scoop trough, and the lower end of the material scoop trough is provided with a material outlet. A corresponding material outlet cover plate and a cover plate cylinder are provided at the material outlet. The cover plate cylinder is connected to the material outlet cover plate and drives the material outlet cover plate to close or open the material outlet.

[0017] Specifically, a direct vibration motor is installed at the feeding channel, and the output end of the direct vibration motor is connected to the feeding channel for transmission.

[0018] Specifically, the mixing cabinet is also equipped with an oxygen detector, which includes a detection unit and a display unit. The detection unit and the display unit are electrically connected. The detection unit is located in the feeding chamber, and the display unit is located outside the mixing cabinet.

[0019] Specifically, a feeding hopper is provided below the mixing chamber, and the feeding space is provided inside the feeding hopper.

[0020] The technical solution of this invention sets up a mixing chamber and a feeding chamber on a mixing cabinet. By pre-loading the additives into the additive cylinder and adding the active metal into the active metal cylinder of the device, the oxygen content in the mixing chamber and the feeding chamber is reduced during the mixing of NdFeB magnets. Then, the additives and active metal are released and added through the additive cylinder and the active metal cylinder, thereby maintaining the sealing and continuity of the addition environment, improving the forming efficiency of NdFeB permanent magnets and reducing the oxidation waste rate of NdFeB powder. Attached Figure Description

[0021] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0022] Figure 2 This is a partial structural schematic diagram of the present invention.

[0023] Figure 3 This is a three-dimensional structural diagram of the active metal barrel of the present invention.

[0024] Figure 4 This is a schematic diagram of the assembly state of the powder screening device and the weighing device of the present invention.

[0025] Figure 5 This is one of the three-dimensional structural schematic diagrams of the weighing device of the present invention.

[0026] Figure 6 This is a second three-dimensional structural schematic diagram of the weighing device of the present invention.

[0027] The attached reference numerals include: 10, mixing cabinet; 11, additive cylinder; 12, active metal cylinder; 13, first pipe; 14, second pipe; 15, sieving device; 16, weighing device; 17, sieving motor; 18, sieve; 19, connecting groove; 20, material hopper; 21, material cover plate; 22, cover plate cylinder; 23, feeding channel; 24, direct vibration motor; 25, oxygen detector; 26, mixing chamber; 27, material outlet. Detailed Implementation

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, top, bottom, inside, outside, vertical, horizontal, longitudinal, counterclockwise, clockwise, circumferential, radial, axial, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0030] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0031] like Figures 1 to 6As shown, a MIM neodymium iron boron screening mixer includes a mixing cabinet, a mixing chamber and a feeding chamber inside the mixing cabinet. An additive cylinder and an active metal cylinder are installed on the feeding chamber. A feeding channel is installed inside the feeding chamber, located below the additive cylinder and the active metal cylinder. The feeding channel is inclined towards the mixing chamber. A vacuum feeding device is installed on one side of the mixing cabinet. A feeding space is installed below the mixing chamber and is connected to the mixing chamber. A vacuum feeding channel is installed between the vacuum feeding device and the feeding space. The mixed material is transferred to the vacuum feeding device through the vacuum feeding channel. During the internal mixing of NdFeB magnets, the additives are first added to the additive cylinder. The additive cylinder is then installed on the mixing cabinet, connecting it to the feeding chamber. Simultaneously, oxygen is purged from the additive cylinder. Next, the active metal is added to the active metal cylinder, which is then installed on the mixing cabinet, connecting it to the feeding chamber. Oxygen is purged from the active metal cylinder as well. During the mixing of NdFeB magnets, pre-oxygen purging is performed on the mixing and feeding chambers to reduce their oxygen content. The additives and active metal are then released and added through the additive and active metal cylinders, maintaining a sealed and continuous mixing environment. This improves the forming efficiency of NdFeB permanent magnets and reduces the oxidation waste rate of NdFeB powder.

[0032] The active metal cylinder includes a cylinder body with a receiving cavity for containing the active metal and an outlet for discharging the active metal. The cylinder body is connected to a feeding chamber via the outlet, and an oxygen venting pipe is provided at the outlet. In this embodiment, the receiving cavity is provided on the cylinder body for containing the active metal cylinder, and then oxygen is vented from the receiving cavity through the oxygen venting pipe to reduce the oxygen content in the receiving cavity. Finally, the active metal is added through the outlet, thereby improving the molding efficiency and molding stability of the NdFeB permanent magnet.

[0033] The oxygen venting pipe includes a first pipe and a second pipe, which are arranged side by side and both are connected to the receiving cavity. Both the first and second pipes are equipped with control valves. Either the first or second pipe is connected to an external inert gas pipe. In this embodiment, during the oxygen venting operation of the active metal cylinder, the external inert gas pipe is connected to the first pipe while the second pipe is opened. The inert gas then enters the receiving cavity through the first pipe, displacing the oxygen within the cavity and causing it to move out of the cavity along the second pipe. This reduces the oxygen content within the cavity. When the oxygen content drops to a suitable level, the second pipe is closed first, followed by the first pipe, thus sealing the active metal cylinder and isolating the cavity from the outside environment. This facilitates the anti-oxidation treatment of the active metal within the cavity. Similarly, the same equipment can be installed on the additive cylinder to achieve anti-oxidation treatment of the additives and prevent the release of oxygen into the feeding chamber when adding additives.

[0034] The active metal cylinder also includes a sieving device and a weighing device, which are located in the feeding chamber and connected to the discharge port from the upper right to the lower left. In this embodiment, the sieving device performs a sieving operation on the active metal coming out of the active metal cylinder to prevent the active metal from clumping together, which would be inconvenient for subsequent processing. At the same time, the sieved active metal is weighed to ensure the addition ratio of active metal and improve the molding effect.

[0035] The powder sieving device includes a powder sieving motor and a powder sieve. The powder sieve is located directly below the discharge port and has a connecting groove. The powder sieving motor is connected to the powder sieve through the connecting groove. In this embodiment, the powder sieving motor drives the powder sieve to vibrate, causing the active metal located in the connecting groove of the powder sieve to fall through the screen to the weighing device below, thereby achieving the sieving of the active metal.

[0036] The weighing device includes a material scoop block located directly below the powder sieve. The scoop block has a material trough, and the lower end of the trough has a material outlet. A corresponding material outlet cover and a cover cylinder are located at the material outlet. The cover cylinder is driven by the material outlet cover and drives the cover to close or open the material outlet. In this embodiment, the material scoop block is used to weigh the screened active metal, and the weighed active metal then enters the feeding channel located below through the material outlet.

[0037] A direct-vibration motor is installed at the feeding channel, and the output end of the direct-vibration motor is connected to the feeding channel drive. In this embodiment, the direct-vibration motor vibrates the feeding channel, thereby facilitating the movement of active metals and additives along the feeding channel into the mixing chamber.

[0038] An oxygen detector is also installed on the internal mixer. The oxygen detector includes a detection unit and a display unit, which are electrically connected. The detection unit is located in the feeding chamber, and the display unit is located outside the internal mixer. In this embodiment, the oxygen detector is used to detect the oxygen content inside the internal mixer, which allows operators to intuitively observe the oxygen content inside the internal mixer, thereby improving monitoring efficiency.

[0039] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the inventive concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A MIM neodymium iron boron screening and internal mixer, characterized in that: The system includes an internal mixer, which contains a mixing chamber and a feeding chamber. The feeding chamber contains additive and active metal cylinders, and a feeding channel located below the additive and active metal cylinders, inclined towards the mixing chamber. A vacuum feeding device is located on one side of the internal mixer, and a feeding space is located below the mixing chamber, connected to it. A vacuum feeding channel connects the vacuum feeding device and the feeding space, allowing the mixed materials to be transferred to the vacuum feeding chamber via the vacuum feeding channel. Inside the empty feeding device, the active metal cylinder includes a cylinder body, which has a receiving cavity for containing the active metal and a discharge port for discharging the active metal. The cylinder body is connected to the feeding chamber through the discharge port, and an oxygen venting pipe is provided at the discharge port. The oxygen venting pipe includes a first pipe and a second pipe, which are arranged side by side and are both connected to the receiving cavity. A control valve is provided on both the first pipe and the second pipe, and the first pipe or the second pipe is connected to an external inert gas pipe.

2. The MIM neodymium iron boron screening mixer according to claim 1, characterized in that: The active metal cylinder also includes a sieving device and a weighing device, which are located in the feeding chamber. The sieving device and the weighing device are connected to the discharge port from the upper right to the lower left.

3. The MIM neodymium iron boron screening mixer according to claim 2, characterized in that: The powder screening device includes a powder screening motor and a powder screening screen. The powder screening screen is located directly below the discharge port. A connecting groove is provided on the powder screening screen, and the powder screening motor is connected to the powder screening screen through the connecting groove.

4. The MIM neodymium iron boron screening and internal mixer according to claim 3, characterized in that: The weighing device includes a material hopper block located directly below the powder sieve. The material hopper block is provided with a material hopper groove, and the lower end of the material hopper is provided with a material outlet. A corresponding material outlet cover plate and a cover plate cylinder are provided at the material outlet. The cover plate cylinder is connected to the material outlet cover plate and drives the material outlet cover plate to close or open the material outlet.

5. The MIM neodymium iron boron screening mixer according to claim 1, characterized in that: A direct vibration motor is installed at the feeding channel, and the output end of the direct vibration motor is connected to the feeding channel for transmission.

6. The MIM neodymium iron boron screening and internal mixer according to claim 1, characterized in that: The mixing cabinet is also equipped with an oxygen detector, which includes a detection unit and a display unit. The detection unit and the display unit are electrically connected. The detection unit is located in the feeding chamber, and the display unit is located outside the mixing cabinet.

7. The MIM neodymium iron boron screening mixer according to claim 1, characterized in that: A feeding hopper is provided below the mixing chamber, and the feeding space is provided inside the feeding hopper.

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