Sealing magnetic field pressing machine

Abstract

The utility model discloses a sealed magnetic field pressing machine which comprises a material storage device, a powder containing box, a pressed blank conveying device, a pressing machine frame, an upper pressing head assembly, a lower pressing head assembly, a mold device and an orientation magnetic pole. The upper pressure head assembly, the mold device, the lower pressure head assembly and the orientation magnetic pole are arranged in the press frame; the mold device, the upper pressing head assembly, the lower pressing head assembly and the orientation magnetic pole conduct two-way pressing on the alloy powder in the mold cavity under magnetic field orientation together, the alloy powder is pressed into a pressed blank, then the upper pressing head assembly and the lower pressing head assembly are moved in the same direction, and the pressed blank is ejected out of the mold cavity; one side of the press frame is connected with the powder containing box, and the other side of the press frame is connected with the pressed blank conveying device. A connector is arranged at the joint of the press frame and the pressed blank conveying device, and a pressed blank door is arranged at the connector. The pressed blank door is opened, and the pressed blank can penetrate through the connector to be conveyed into the pressed blank conveying device; the sealed magnetic field pressing machine works under the protective atmosphere, and alloy powder and pressed blanks are isolated from the atmosphere in the magnetic field forming process.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of advanced equipment, especially relates to a sealed magnetic field press, which can be used for manufacturing rare earth permanent magnet materials. BACKGROUND

[0002] Rare earth permanent magnet materials mainly made of sintered neodymium iron boron are applied more and more widely due to their excellent magnetic properties and are widely used in medical magnetic resonance imaging, computer hard drive, sound, mobile phone and the like; with the requirements of energy saving and low-carbon economy, the neodymium iron boron rare earth permanent magnet material is also widely used in the fields of automobile parts, air conditioner compressor, energy saving and control motor, hybrid electric vehicle, wind power and the like.

[0003] The industrial production of rare earth permanent magnet materials generally adopts powder metallurgy technology, that is, rare earth permanent magnet alloy is made into alloy powder with a particle size of 3-5 microns, and then the alloy powder is oriented and formed under a magnetic field; the formed body needs to be isostatic pressed after being taken out, and then the pressed compact is vacuum sintered to obtain a rare earth permanent magnet sintered blank, that is, a rare earth permanent magnet material. The rare earth permanent magnet alloy powder is extremely easy to oxidize and can even self-ignite in the air, so it must be isolated from the atmospheric environment during the production process of the rare earth permanent magnet material. The oxidation problem in the production process has been restricting the development of the industry and seriously affecting the consistency of products. In order to improve the performance, the powder particle size is further reduced to below 3 microns from 3-5 microns, and the surface area is significantly increased. Since the rare earth permanent magnet powder cannot be granulated, the powder is more prone to oxidation and has poorer formability. In order to solve the problem of poor formability, the existing technology solves the problem by first pressing the compact into a compact with a lower density, and then increasing the density by isostatic pressing. This method effectively solves the problem of poor formability, but the compact needs to be packaged in a protective atmosphere before isostatic pressing, and the outer packaging of the compact is full of isostatic pressing oil after isostatic pressing, which results in a poor working environment and easy environmental pollution, so it is very necessary to cancel the isostatic pressing process. Although many enterprises invest in research and development to cancel the isostatic pressing technology, it is not ideal, and the process technology cannot cover all products, especially for high-performance, large-size and fine-grained products, which still cannot meet the requirements. At present, although sealed equipment is also used to complete the magnetic field forming of the alloy powder in the industry, some links in the actual production process of the magnetic field forming still cannot be completely and effectively isolated from the atmosphere, which has a certain impact on the quality of the sintered neodymium iron boron material produced thereby and limits the further improvement of the performance of the material.

[0004] In addition, the press equipment and the vacuum sintering furnace equipment currently used in the industry have poor production line adaptation. In the process of forming the alloy powder into a compact and loading the compact into the vacuum sintering furnace, manual operation is usually required to complete the work of placing and loading the compact material into a box, stacking the material box into the furnace, and transporting the material between the magnetic field forming and vacuum sintering processes. This brings several problems, including that the material is easily exposed to the external environment for a long time during manual operation, causing different degrees of oxidation and affecting the further improvement of the performance of rare earth permanent magnet materials. In addition, manual operation not only reduces production efficiency, consumes human resources, and increases production costs, but also affects the stability of product quality due to the uncertainty of manual operation, resulting in a certain rate of defective products. Therefore, there is an urgent need to develop a magnetic field press equipment with better production line adaptation and higher automation to solve this technical situation. SUMMARY

[0005] To solve the above problems, the utility model provides a sealed magnetic field press for manufacturing high-quality rare earth permanent magnet materials and matching with a highly automated and intelligent rare earth permanent magnet production line.

[0006] The sealed magnetic field press comprises a storage device, a powder loading box, a compact conveying device, a press frame, an upper press head assembly, a lower press head assembly, a mold device, and an orientation magnetic pole. The storage device comprises a powder storage box. The storage device is arranged above the powder loading box. A powder loading device is arranged in the powder loading box, which automatically quantitatively loads the alloy powder in the storage device into the mold cavity of the mold device. The upper press head assembly, the mold device, the lower press head assembly, and the orientation magnetic pole are arranged in the press frame. The upper press head assembly and the lower press head assembly are arranged above and below the mold device, respectively. There are two orientation magnetic poles, which are distributed on both sides of the mold device. The mold device, together with the upper press head assembly, the lower press head assembly, and the orientation magnetic pole, realizes bidirectional pressing of the alloy powder in the mold cavity under magnetic field orientation, and then moves the upper press head assembly and the lower press head assembly in the same direction to eject the compact from the mold cavity. One side of the press frame is connected with the powder loading box, and the other side is connected with the compact conveying device. An interface is arranged at the connection between the press frame and the compact conveying device, and a compact door is arranged at the interface. After the compact door is opened, the compact can be conveyed to the compact conveying device through the interface. After the compact door is closed, the storage device, the powder loading box, and the press frame form an independent space isolated from the atmosphere. The press frame can move relative to the compact conveying device. The sealed magnetic field press works in a protective atmosphere, and the alloy powder and the compact are isolated from the atmosphere during the magnetic field forming process.

[0007] The storage device comprises an alloy powder tank and a glove box; the alloy powder tank is connected with the glove box through a valve; the glove box is connected with a powder storage tank; a sealing cover is arranged at the connection between the glove box and the powder storage tank; the powder in the alloy powder tank can pass through the glove box and enter the powder storage tank by opening the valve and the sealing cover.

[0008] The applicant finds that in the use of the existing magnetic field press, when the powder tank is connected with the press, due to the inherent structure, the alloy powder will be oxidized to different degrees when being transported from the powder tank to the press, and a certain proportion of waste powder will be produced, which will participate in the production of the rare earth permanent magnet compact after entering the press, and will cause the performance of the rare earth permanent magnet material to fluctuate, affect the consistency of the performance of the sintered neodymium-iron-boron product, and also limit the further improvement of the material performance. In the utility model, the glove box is arranged on the conveying channel between the alloy powder tank and the sealing magnetic field press, and the valve and the sealing cover are combined to work, so that the alloy powder is not in contact with the atmosphere during the process of entering the sealing magnetic field press from the alloy powder tank, the inherent waste powder problem in the production process of the existing equipment is overcome, and the quality and performance consistency of the rare earth permanent magnet material are ensured, and the performance of the rare earth permanent magnet material is further improved.

[0009] The sealing magnetic field press further comprises a first servo hydraulic cylinder assembly and a second servo hydraulic cylinder assembly; the first servo hydraulic cylinder assembly comprises a first hydraulic cylinder, a first reversing valve, a first hydraulic pump and a first servo motor; the second servo hydraulic cylinder assembly comprises a second hydraulic cylinder, a second reversing valve, a second hydraulic pump and a second servo motor; the first servo hydraulic cylinder assembly and the second servo hydraulic cylinder assembly are arranged outside the press frame, and the first hydraulic cylinder and the second hydraulic cylinder are connected with the upper die head assembly and the lower die head assembly respectively; the displacement of the upper die head assembly and the lower die head assembly and the pressure of the alloy powder in the mold cavity are accurately controlled by controlling the first servo motor and the second servo motor. When the first hydraulic cylinder works, any other executing device on the first servo hydraulic cylinder assembly cannot work; similarly, when the second hydraulic cylinder works, any other executing device on the second servo hydraulic cylinder assembly cannot work.

[0010] The upper die head assembly and the lower die head assembly can move according to the set program curve, realize bidirectional pressing according to the set process curve and protect demolding, and the displacement accuracy of the upper die head assembly and the lower die head assembly is higher than 0.1 mm, the pressure accuracy is higher than 0.1 MPa, and the size accuracy of the compact is higher than 0.1 mm.

[0011] The sealing magnetic field press further comprises a press support frame, and the press frame is supported on the press support frame; the press frame can move relative to the compact conveying device. In an embodiment, the press support frame is provided with a roller and a third hydraulic cylinder; the third hydraulic cylinder drives the press frame to move relative to the compact conveying device; the press frame can also move relative to the powder tank.

[0012] After the alloy powder is loaded into the die cavity, the alloy powder is subjected to magnetic field orientation, after the orientation current reaches the set value, the upper punch assembly descends according to the set first speed curve, stops descending when the first set pressure is reached; the lower punch assembly ascends according to the set second speed curve, stops ascending when the second set pressure is reached, realizing bidirectional pressure; after the die is demagnetized, the upper punch assembly ascends according to the set third speed curve, rapidly ascends when the first set position is reached; the lower punch assembly ascends according to the set fourth speed curve, stops ascending when the second set position is reached.

[0013] The first set pressure is greater than or equal to the second set pressure, and the second set pressure is greater than or equal to 5 MPa; the green compact density is greater than or equal to 4.1 g / cm 3 .

[0014] In the existing powder loading process of the magnetic field press, since the rare earth permanent magnet alloy powder cannot be granulated, the powder flowability is poor, and the magnetic field formability is very poor, which affects the magnetic field forming effect. In particular, in order to improve the performance of the rare earth permanent magnet material, the technical means of refining the alloy powder is mostly adopted at present, which leads to the formability of the alloy powder with finer particle size to be even worse. In order to solve the problem of poor forming, the existing technology solves the problem by first pressing the alloy powder into an intermediate formed body with a lower density, and then further increasing the density through an isostatic pressing process. Although this method effectively solves the problem of poor forming, the intermediate formed body needs to be packaged in a protective atmosphere before isostatic pressing, which is very troublesome to operate. In addition, the outer package of the green compact is full of isostatic pressing oil after isostatic pressing, which is troublesome to clean and has a poor working environment. Although there is a demand to cancel the isostatic pressing in the industry, the effect has not been ideal, especially for the case of finer alloy powder, the isostatic pressing is difficult to replace.

[0015] The displacement and pressure of the upper punch assembly and the lower punch assembly of the sealing magnetic field press can be precisely controlled, the green compact density can be uniform, the size is consistent, and the green compact has the required density and size. In the pressing process, the upper punch assembly and the lower punch assembly can move according to the set program curve, the pressure of the upper punch assembly and the lower punch assembly can also be fed back according to the servo output, even for finer alloy powder, effective pressing forming can be realized, and the green compact has uniform density everywhere, so that the inherent technical problem in the industry can be overcome, the isostatic pressing in the forming process can be cancelled, and the magnetic performance of the rare earth permanent magnet material can be further improved.

[0016] The green compact conveying device is connected with the press frames of the plurality of sealing magnetic field presses through interfaces respectively; the green compact conveying device is further connected with a first device; the green compact conveying device serves as a conveying passage of the plurality of sealing magnetic field presses, and conveys the green compacts pressed by the sealing magnetic field presses into the first device. In an optimal embodiment, the first device is a boxing box for boxing the green compacts pressed by the sealing magnetic field presses.

[0017] The sealing magnetic field presser can be applicable to an automatic magnetic field forming system, the system comprising a boxing box, a conveying box and the sealing magnetic field presser; the sealing magnetic field presser has multiple machines and is connected to the green compact conveying device in parallel; in a more preferred embodiment, the automatic magnetic field forming system comprises four or more sealing magnetic field pressers. The sealing magnetic field presser can move relative to the green compact conveying device. One end of the green compact conveying device is connected to the boxing box; the green compact conveying device, the boxing box and the sealing magnetic field presser in the working state form an atmosphere-isolated space, which is filled with protective gas; the green compact pressed by the sealing magnetic field presser can be automatically conveyed into the green compact conveying device, and the green compact conveying device serves as a conveying channel of the automatic magnetic field forming system, conveying the green compact pressed by each sealing magnetic field presser into the boxing box; the boxing box comprises a material box moving device, a material taking mechanism and a first isolation valve; in the boxing box, the material taking mechanism grabs the green compact and loads it into the sintering material box on the material box moving device; the conveying box is provided with a material box holding and lifting device and a second isolation valve; the conveying box can be moved to the opposite side of the boxing box, and is connected to or separated from the boxing box; after the conveying box is connected to the boxing box, the first isolation valve and the second isolation valve are opened, the boxing box and the conveying box form an atmosphere-isolated space, and the material box moving device can be moved into the conveying box; through the cooperation of the material box moving device and the material box holding and lifting device, the multiple layers of sintering material boxes on the material box holding and lifting device can be moved to the material box moving device layer by layer, or the multiple layers of sintering material boxes are stacked together, and the process of automatically loading the green compact into the sintering material box and automatically stacking the sintering material box is completed. The first isolation valve and the second isolation valve are closed, and the conveying box and the boxing box form atmosphere-isolated spaces respectively, and the conveying box loaded with the multiple layers of sintering material boxes is moved away from the boxing box.

[0018] In a more preferred embodiment, the conveying box is automatically moved to the opposite side of the vacuum sintering furnace after being separated from the boxing box, is connected to the vacuum sintering furnace, and conveys the sintering material box loaded with the green compact in the conveying box into the vacuum sintering furnace for vacuum sintering. In a more preferred embodiment, the vacuum sintering furnace has four or more machines.

[0019] A sensor for detecting whether there is a green compact at the position is arranged near the interface between the sealing magnetic field presser and the green compact conveying device, and the sensor is used for controlling the green compact pressed by different sealing magnetic field pressers from colliding with each other.

[0020] The powder loading box is further provided with an electronic scale assembly; the powder loading device is arranged below the electronic scale assembly; after the alloy powder passes through the electronic scale assembly and is weighed according to the set weight, the alloy powder enters the powder loading device.

[0021] The press frame and the powder loading box are movable; when the sealed magnetic field press needs to be maintained, the press frame can be disconnected from the compact transfer device, and then the press frame and the powder loading box are moved away from the compact transfer device; when the sealed magnetic field press needs to resume the working state after the maintenance is completed, the press frame and the powder loading box are moved to the compact transfer device, and the connection between the press frame and the compact transfer device is restored. The moving mode of the press frame and the powder loading box is selected from at least one of the wheel type moving and the sliding rail moving.

[0022] A compact door is arranged at the interface between the sealed magnetic field press and the compact transfer device; when the sealed magnetic field press is disconnected from the compact transfer device, the compact door needs to be closed first to seal the compact transfer device and keep the atmosphere of the sealed space formed by the compact transfer device, the box loading box and the sealed magnetic field press in the working state unchanged. The maintenance of the sealed magnetic field press includes replacement of the mold, cleaning and repair of the alloy powder in the press frame and the powder loading box, and other work. During the working process of the sealed magnetic field press, a small amount of alloy powder will be attached to the inside of the press frame and the powder loading box, and this part of the alloy powder needs to be cleaned regularly to avoid combustion when exposed to the atmosphere and cause accidents. The compact transfer device is a public transfer channel of the compacts in the automatic magnetic field forming system, and transfers the compacts pressed by each sealed magnetic field press to the box loading box. Even if a sealed magnetic field press is maintained or resumes the working state after the maintenance is completed, the air tightness of the compact transfer device is not affected, and the compact transfer device can still provide automatic transfer of compacts for other sealed magnetic field presses as a public transfer channel, ensuring that the automatic magnetic field forming system and the rare earth permanent magnet production line including the automatic magnetic field forming system can still operate normally.

[0023] Although, there are some forms of automatic press system in the industry, which connects multiple presses through a channel, but it sets up a mechanical arm in each press to take material and box, and then passes the box through multiple trolleys in the channel, the number of mechanical arms and trolleys is large, the structure and action are complex and complicated, in addition, the box filling action in each press also requires a set of empty box conveying device to be equipped in each press, and the complicated empty box conveying action is carried out, the above design not only increases the system equipment cost, more importantly, reduces the running efficiency of the whole system, increases the failure rate, and affects the production efficiency. The sealed magnetic field press of the utility model directly conveys the rare earth alloy powder pressed into a compacted blank to the conveying belt arranged in the compacted blank conveying device, and collects the compacted blanks into a unified box through the conveying belt, the compacted blank conveying device is a public conveying channel of multiple sealed magnetic field presses, and the compacted blanks pressed by each sealed magnetic field press are conveyed into the box, and only one set of compacted blank grabbing mechanism is arranged in the box, the compacted blank is grabbed by the compacted blank grabbing mechanism and placed in the sintering box in the box, then the butt joint of the conveying box and the box is realized, the reciprocating movement of the box moving device of the box and the lifting of the box lifting device in the conveying box are realized, and the action of the compacted blank grabbing mechanism is matched, so that the process of automatically filling the compacted blank into the sintering box and automatically stacking the sintering box is completed, and in the process, the empty box is conveyed to the box, the compacted blank is filled into the box, and the box is stacked at the same time, which simplifies the device structure, compresses the equipment size, reduces the equipment cost, more importantly, improves the overall running efficiency of the system, reduces the equipment failure rate, is beneficial to the smooth operation of the whole system, and improves the production efficiency.

[0024] In the preferred embodiment of the utility model, the conveying feeder further comprises a material bed; the sintering material boxes in the conveying feeder are multiple, arranged in n layers from top to bottom and placed on the material bed, and n>=3. The process of automatically loading the compacts into the sintering material boxes and automatically stacking the sintering material boxes comprises the following steps: after the loading box is butted against the conveying feeder, the material box lifting device lifts all the n layers of empty sintering material boxes from the material bed, the material box moving device moves horizontally from the loading box into the conveying feeder, then the material box lifting device lowers the n layers of empty sintering material boxes onto the material box moving device, the material box lifting device lifts (n-1) layers of empty sintering material boxes, the material box moving device moves the remaining 1 layer of empty sintering material boxes from the conveying feeder into the loading box, then the material box moving device moves up and down, loads the compacts into the sintering material boxes in the loading box, then the material box moving device moves the sintering material boxes loaded with the compacts horizontally into the conveying feeder, then the material box lifting device lowers (n-1) layers of empty sintering material boxes above the layer of sintering material boxes on the material box moving device, the material box lifting device lifts (n-2) layers of empty sintering material boxes, the material box moving device moves 2 layers of sintering material boxes including 1 layer of empty sintering material boxes from the conveying feeder into the loading box, loads the compacts into the empty sintering material boxes in the loading box, and the process is repeated until n layers of empty sintering material boxes are loaded with the compacts in the loading box and then moved into the conveying feeder, then the material box lifting device lifts n layers of sintering material boxes loaded with the compacts from the material box moving device, the material box moving device returns to the loading box, and the material box lifting device lowers n layers of sintering material boxes onto the material bed.

[0025] The sealed magnetic field press and the automatic magnetic field forming system in the utility model are used to make the process of forming compacts from rare earth permanent magnet alloy powder and loading the compacts into a vacuum sintering furnace in the production of rare earth permanent magnet materials be completed automatically under nitrogen protection or vacuum conditions, so that the rare earth permanent magnet raw materials which are very easy to oxidize are effectively isolated from the atmospheric environment at all times, the oxygen content in the materials is reduced, the performance of the rare earth permanent magnet materials is further improved, the material preparation, loading into boxes, stacking into furnaces and the transportation of the materials between the magnetic field forming and vacuum sintering processes in the process are all completed in an automatic manner, the production efficiency is improved, the human resources are saved, the production cost is reduced, the uncertainty of manual operation is eliminated, the product failure rate is reduced, the inherent technical problems in the industry are overcome, and the stability of the product quality is improved. Under the same raw material composition and manufacturing process parameters, the oxygen content in the rare earth permanent magnet material manufactured by using the technical scheme in the utility model is reduced by about 200ppm, and the product failure rate caused in the process is reduced by about 30%.

[0026] The utility model is according to new technology production line equipment application, mainly solves following problem:

[0027] 1. The difficulty of producing Nd-Fe-B rare earth permanent magnet is that the rare earth permanent magnet alloy is very easy to oxidize, the powder particle size is fine, the powder cannot be granulated, and the magnetic field forming is difficult. Some equipment, such as being able to complete the isolation from the atmosphere, actually wastes a large amount of nitrogen, and the oxygen content cannot be reduced. The oxygen content of the equipment production process of the present application is less than 200ppm. In order to reduce the oxidation of the rare earth permanent magnet alloy powder, reduce the consumption of rare earth, and improve the magnetic performance, the rare earth praseodymium neodymium is partially replaced by rare earth lanthanum cerium, and the oxygen content of the equipment production process of the present application is less than 100ppm.

[0028] 2. The magnetic field forming property of the fine powder is realized, the coercive force is improved, and the consumption of heavy rare earth elements dysprosium and terbium is reduced. When the existing technology cancels isostatic pressing, the average particle size of the powder is generally higher than 3.5μm, and when the average particle size of the powder is less than 2.8μm, the sealed magnetic field press also has good magnetic field forming property, which is suitable for batch production.

[0029] 3. The powder filling device in the powder filling box of the present application uniformly fills the powder into the mold, and forms according to the set process curve. Under the condition of canceling isostatic pressing, the green compact density is greater than 4.5g / cm 3 .

[0030] 4. The green compact conveying device changes the existing technology. After the green compact is taken out from the mold, it is directly placed on the conveying belt in the green compact conveying device. One conveying belt connects all the magnetic field presses and conveys the green compact to the same boxing box. The structure is simple and reliable, the operation is convenient, the equipment cost is low, and the practicability is strong.

[0031] 5. The existing technology sets a boxing box in front of each press. Then the material box filled with green compacts is conveyed into the glove box of the vacuum sintering furnace, and the glove box is connected with the vacuum sintering furnace. The equipment is complex and easy to cause the oxygen content of the green compact to increase. In addition, this structure actually cannot realize intelligent production. The conveying belt of the present application directly brings the green compact into the boxing box, and the green compact is filled into the sintering material box by the visual mechanical hand in the boxing box. After the conveying material box is conveyed, it is connected with the sintering furnace. The oxygen content is low, nitrogen is saved, and the degree of automation is high.

[0032] 6. The conveying material box of the existing technology cannot be directly connected with the vacuum sintering furnace, and is conveyed to a transitional glove box first, and then conveyed to the vacuum sintering furnace by the glove box. The conveying material box of the present application is connected with the boxing box, and after the boxing box is removed, it is directly connected with the vacuum sintering furnace. The empty sintering material box is conveyed back to the boxing box through the conveying material box, and intelligent operation is realized. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 is a structural schematic diagram of an embodiment of the magnetic field press of the present application.

[0034] Figure 2 is a top view structural layout schematic diagram of one embodiment of the automatic magnetic field forming system. DETAILED DESCRIPTION

[0035] As Figure 1 shown, the magnetic field press 1 of the utility model comprises a storage device 2, a powder loading box 3, a compact transfer device 10, a press frame 4, an upper press head assembly 5, a lower press head assembly 6, a mold device 7 and an orientation magnetic pole 8. The storage device 2 is arranged above the powder loading box 3; the powder loading box 3 is provided with a powder loading device 9, which automatically quantitatively loads the alloy powder in the storage device 2 into the mold cavity of the mold device 7; the upper press head assembly 5, the mold device 7, the lower press head assembly 6 and the orientation magnetic pole 8 are arranged in the press frame 4; the upper press head assembly 5 and the lower press head assembly 6 are arranged above and below the mold device 7 respectively; the orientation magnetic pole 8 has two, which are distributed on both sides of the mold device 7.

[0036] The press frame is further provided with an orientation coil, which is sleeved outside the orientation magnetic pole.

[0037] The mold device, together with the upper press head assembly, the lower press head assembly and the orientation magnetic pole, realizes bidirectional pressing of the alloy powder in the mold cavity under magnetic field orientation, presses the alloy powder into a compact, then moves the upper press head assembly and the lower press head assembly to eject the compact from the mold cavity.

[0038] One side of the press frame 4 is connected with the powder loading box 3, and the other side is provided with an interface, which can be connected with the compact transfer device 10 through the interface; the compact transfer device 10 is provided with a compact door 17 at the interface; after the compact door 17 is closed, the storage device 2, the powder loading box 3 and the press frame 4 form an independent space isolated from the atmosphere; after the compact door 17 is opened, the compact can be transferred to the compact transfer device 10 through the interface; the press frame 4 can move relative to the compact transfer device 10. The working process of the magnetic field press is completed under gas protection.

[0039] The storage device 2 comprises an alloy powder tank 18, a glove box 19 and a powder storage box 20; the alloy powder tank 18 is connected with the glove box 19 through a valve, and the glove box 19 is connected with the powder storage box 20. A sealing cover is arranged at the connection between the glove box and the powder storage box; after the valve and the sealing cover are opened, the powder in the alloy powder tank can pass through the glove box and enter the powder storage box.

[0040] The magnetic field press 1 further comprises a first servo hydraulic cylinder assembly 21 and a second servo hydraulic cylinder assembly 22; the first servo hydraulic cylinder assembly 21 comprises a first hydraulic cylinder 23, a first reversing valve, a first hydraulic pump 24 and a first servo motor 25; the second servo hydraulic cylinder assembly 22 comprises a second hydraulic cylinder 26, a second reversing valve, a second hydraulic pump 27 and a second servo motor 28; the first servo hydraulic cylinder assembly 21 and the second servo hydraulic cylinder assembly 22 are both arranged outside the press frame 4, the first hydraulic cylinder 23 and the second hydraulic cylinder 26 pass through the press frame 4 and are connected with the upper punch assembly 5 and the lower punch assembly 6 respectively; the displacement of the upper punch assembly 5 and the lower punch assembly 6 and the pressure of the powder in the die cavity are accurately controlled by controlling the first servo motor 25 and the second servo motor 28.

[0041] When the first hydraulic cylinder works, any other executing device on the first servo hydraulic cylinder assembly cannot work; similarly, when the second hydraulic cylinder works, any other executing device on the second servo hydraulic cylinder assembly cannot work.

[0042] The upper punch assembly and the lower punch assembly can move according to the set program curve, realize bidirectional pressing according to the set process curve and protect demolding, the moving precision of the upper punch assembly and the lower punch assembly is higher than 0.05 mm, the pressure precision is higher than 0.1 MPa, and the size precision of the compact is higher than 0.05 mm.

[0043] The magnetic field press further comprises a press support frame 29, the press frame 4 is supported on the press support frame 29; the press support frame is provided with a roller 30 and a third hydraulic cylinder.

[0044] The third hydraulic cylinder drives the press frame to move relative to the compact conveying device; the press frame can also move relative to the powder loading box.

[0045] After the alloy powder is loaded into the die cavity, the alloy powder is subjected to magnetic field orientation, when the orientation current reaches the set value, the upper punch assembly descends according to the set first speed curve, stops descending when the first set pressure is reached; the lower punch assembly ascends according to the set second speed curve, stops ascending when the second set pressure is reached, to realize bidirectional pressing; after the die is demagnetized, the upper punch assembly ascends according to the set third speed curve, rapidly ascends when the first set position is reached; the lower punch assembly ascends according to the set fourth speed curve, stops ascending when the second set position is reached.

[0046] The first set pressure is greater than or equal to the second set pressure, and the first set pressure is higher than the second set pressure by more than 0.5 MPa, and the second set pressure is greater than or equal to 6 MPa; the compact density is greater than or equal to 4.1 g / cm 3 .

[0047] A sensor is installed near the interface connecting the magnetic field press and the billet conveying device to detect whether there is a billet at that location. The sensor is used to control the billets pressed by different magnetic field presses to prevent collisions.

[0048] An electronic scale assembly is also installed inside the powder filling box; the powder filling device is located below the electronic scale assembly; the alloy powder is weighed by the electronic scale assembly according to the set weight before entering the powder filling device.

[0049] The magnetic field press is also equipped with a transfer mechanism, which automatically removes the pressed blank from the mold cavity and places it into the pressed blank conveying device.

[0050] Both the press frame and the powder hopper are movable. When the magnetic press requires maintenance, the press frame can be disconnected from the billet conveying device, and then the press frame and powder hopper can move away from the billet conveying device. When the magnetic press needs to be restored to working condition after maintenance, the press frame and powder hopper move towards the billet conveying device, and the connection between the press frame and the billet conveying device is restored. The movement method of the press frame and powder hopper is selected from at least one of wheeled movement and slide rail movement. Figure 1 In the implementation method, both the press support frame and the lower part of the powder box are equipped with rollers, which can be used to move the press.

[0051] The billet conveying device is connected to the press frames of multiple magnetic field presses via interfaces. A first device is also connected to the end of the billet conveying device; the billet conveying device serves as a common conveying channel for the multiple magnetic field presses, conveying the billets pressed by each magnetic field press to the first device. In a preferred embodiment, the first device is a boxing box used to box the billets pressed by the magnetic field presses.

[0052] The magnetic field press of this invention can be applied to an automatic magnetic field forming system, such as... Figure 2 As shown, the system includes a carton 11, a conveyor hopper 15, and the aforementioned magnetic field press 1; there are multiple magnetic field presses 1, and the press frames of the multiple magnetic field presses are connected side-by-side to the blank conveying device 10. Figure 2 In the illustrated embodiment, the automated magnetic field forming system includes four magnetic field presses. The press frames of the magnetic field presses are movable relative to the blank conveying device. One end of the blank conveying device 10 is connected to the box 11; the blank conveying device 10, the box 11, and the magnetic field presses in operation form an atmosphere-isolated space filled with protective gas. The blanks pressed by the magnetic field presses are automatically conveyed into the blank conveying device, which serves as the conveying channel of the automated magnetic field forming system, conveying the blanks pressed by each magnetic field press into the box.

[0053] The boxing box 11 comprises a magazine moving device, a material taking mechanism and a first isolation valve 12; in the boxing box 11, the material taking mechanism grabs the compacted body and puts it into the sintering magazine 13 on the magazine moving device. Figure 1 and Figure 2 As shown in the figure, the compacted body conveying device 10 is provided with a conveying belt 14, which extends through the interface into the boxing box 11; after the compacted body is ejected from the mold cavity, it is moved onto the conveying belt 14 in the compacted body conveying device, and then the compacted body is conveyed to the boxing box 11 through the conveying belt 14.

[0054] The feeding box 15 is provided with a magazine holding and lifting device and a second isolation valve 16. The feeding box 15 can be moved to the opposite side of the boxing box 11, and is connected or separated from the boxing box 11. After the feeding box 15 is connected to the boxing box 11, the first isolation valve 12 and the second isolation valve 16 are opened, the boxing box 11 and the feeding box 15 form a space isolated from the atmosphere, and the magazine moving device can be moved into the feeding box 15; through the cooperation of the magazine moving device and the magazine holding and lifting device, the multiple layers of sintering magazines on the magazine holding and lifting device can be moved to the magazine moving device layer by layer, or the multiple layers of sintering magazines can be stacked together, and the process of automatically loading the compacted body into the sintering magazine and automatically stacking the sintering magazine is completed. After the first isolation valve 12 and the second isolation valve 16 are closed, the feeding box 15 and the boxing box 11 form a space isolated from the atmosphere, respectively, and the feeding box 15 loaded with multiple layers of sintering magazines is moved away from the boxing box 11.

[0055] In a more preferred embodiment, after the feeding box is separated from the boxing box, it is automatically moved to the opposite side of the vacuum sintering furnace and is connected to the vacuum sintering furnace, so that the sintering magazine loaded with the compacted body in the feeding box is conveyed into the vacuum sintering furnace for vacuum sintering. In a more preferred embodiment, there are four or more vacuum sintering furnaces.

[0056] A compacted body door is arranged at the interface between the magnetic field press and the compacted body conveying device; when the magnetic field press is disconnected from the compacted body conveying device, the compacted body door needs to be closed first, so that the compacted body conveying device is sealed and air leakage is prevented, and the atmosphere of the sealed space formed by the compacted body conveying device, the boxing box and the magnetic field press in working state is continuously maintained. The maintenance of the automatic magnetic field press includes replacement of the mold, cleaning and repair of the alloy powder in the press frame and the powder loading box, etc.

[0057] The boxing box comprises a boxing box body, one end of the boxing box body is connected to the first isolation valve, and the other end is connected to the compacted body conveying device; the material taking mechanism and the magazine moving device are arranged in the boxing box body; the material taking mechanism puts the compacted body conveyed into the boxing box body into the sintering magazine on the magazine moving device; after the boxing box and the feeding box are connected, the magazine moving device can move back and forth between the boxing box and the feeding box. The magazine moving device can move horizontally or vertically.

[0058] In the preferred embodiment of the present application, the conveying magazine further comprises a material bed; the sintering material boxes in the conveying magazine are multiple, arranged in n layers from top to bottom and placed on the material bed, n≥3. The aforementioned process of automatically loading the compacts into the sintering material boxes and automatically stacking the sintering material boxes comprises: after the loading box is butted against the conveying magazine, the box lifting device lifts all the n layers of empty sintering material boxes from the material bed, the box moving device moves horizontally from the loading box into the conveying magazine, then the box lifting device lowers the n layers of empty sintering material boxes onto the box moving device, the box lifting device lifts (n-1) layers of empty sintering material boxes, the box moving device moves the remaining 1 layer of empty sintering material boxes from the conveying magazine into the loading box, then the box moving device moves up and down, loads the compacts into the sintering material boxes in the loading box, then the box moving device moves the sintering material boxes containing the compacts horizontally into the conveying magazine, then the box lifting device lowers (n-1) layers of empty sintering material boxes above the layer of sintering material boxes on the box moving device, the box lifting device lifts (n-2) layers of empty sintering material boxes, the box moving device moves 2 layers of sintering material boxes including 1 layer of empty sintering material boxes from the conveying magazine into the loading box, loads the compacts into the empty sintering material boxes in the loading box, and so on, until n layers of empty sintering material boxes are all loaded with compacts in the loading box and then moved into the conveying magazine, then the box lifting device lifts n layers of sintering material boxes containing the compacts from the box moving device, the box moving device returns to the loading box, and the box lifting device lowers n layers of sintering material boxes onto the material bed.

Claims

1. A sealed magnetic field press, characterized by: The sealing magnetic field press comprises a storage device, a powder loading box, a green compact conveying device, a press frame, an upper punch assembly, a lower punch assembly, a die device and an orientation magnetic pole; the storage device comprises a powder storage box; the storage device is arranged above the powder loading box; a powder loading device is arranged in the powder loading box, which automatically quantitatively loads the alloy powder in the powder storage box into the die cavity of the die device; the upper punch assembly, the die device, the lower punch assembly and the orientation magnetic pole are arranged in the press frame; the upper punch assembly and the lower punch assembly are arranged above and below the die device respectively; the orientation magnetic pole has two poles and is distributed on both sides of the die device; the die device, together with the upper punch assembly, the lower punch assembly and the orientation magnetic pole, performs bidirectional pressing on the alloy powder in the die cavity under the magnetic field orientation, and then the alloy powder is pressed into a green compact, and then the upper punch assembly and the lower punch assembly are moved in the same direction to eject the green compact from the die cavity; one side of the press frame is connected with the powder loading box, and the other side is connected with the green compact conveying device; an interface is arranged at the connection between the press frame and the green compact conveying device, and a green compact door is arranged at the interface; after the green compact door is opened, the green compact can pass through the interface and be conveyed into the green compact conveying device; the sealing magnetic field press works in a protective atmosphere, and the alloy powder and the green compact are isolated from the atmosphere during the magnetic field forming process.

2. The sealed magnetic field press of claim 1, wherein: The storage device further comprises an alloy powder tank and a glove box; the alloy powder tank is connected with the glove box through a valve, and the glove box is connected with the powder storage box; a sealing cover is arranged at the connection between the glove box and the powder storage box; after the valve and the sealing cover are opened, the powder in the alloy powder tank can enter the powder storage box through the glove box.

3. The sealed magnetic field press of claim 1, wherein: The sealing magnetic field press further comprises a first servo hydraulic cylinder assembly and a second servo hydraulic cylinder assembly; the first servo hydraulic cylinder assembly comprises a first hydraulic cylinder, a first reversing valve, a first hydraulic pump and a first servo motor; the second servo hydraulic cylinder assembly comprises a second hydraulic cylinder, a second reversing valve, a second hydraulic pump and a second servo motor; the first hydraulic cylinder and the second hydraulic cylinder are connected with the upper punch assembly and the lower punch assembly respectively; the displacement of the upper punch assembly and the lower punch assembly and the pressure applied to the alloy powder in the die cavity are accurately controlled by controlling the first servo motor and the second servo motor.

4. The sealed magnetic field press of claim 3, wherein: The upper punch assembly and the lower punch assembly can move according to a set program curve, realize bidirectional pressing according to a set process curve and protective demolding, the displacement accuracy of the upper punch assembly and the lower punch assembly is higher than 0.1 mm, and the pressure accuracy is higher than 1 MPa.

5. The sealed magnetic field press of claim 1, wherein: The sealing magnetic field press further comprises a press support frame, and the press frame is supported on the press support frame; the press frame can move relative to the green compact conveying device.

6. The sealed magnetic field press of claim 1, wherein: The sealing magnetic field press further comprises a press support frame, and the press frame is supported on the press support frame; the press support frame is provided with a roller and a third hydraulic cylinder; the third hydraulic cylinder drives the press frame to move relative to the green compact conveying device; the press frame can also move relative to the powder loading box.

7. The sealed magnetic field press of claim 1, wherein: After the alloy powder is loaded into the die cavity, the alloy powder is subjected to magnetic field orientation, the orientation current reaches a set value, the upper punch assembly descends according to a set first speed curve, stops descending when a first set pressure is reached, the lower punch assembly ascends according to a set second speed curve, stops ascending when a second set pressure is reached, bidirectional pressure is realized, the die is demagnetized, the upper punch assembly ascends according to a set third speed curve, rapidly ascends when a first set position is reached, the lower punch assembly ascends according to a set fourth speed curve, stops ascending when a second set position is reached.

8. The sealed magnetic field press of claim 7, wherein: The first set pressure is greater than or equal to the second set pressure, and the second set pressure is greater than or equal to 5 MPa.

9. The sealed magnetic field press of claim 1, wherein: The compact conveying device is connected with the press frames of the plurality of sealed magnetic field presses through interfaces respectively; the compact conveying device is further connected with a first device; the compact conveying device serves as a conveying passage of the plurality of sealed magnetic field presses, and conveys the compacts pressed by the sealed magnetic field presses into the first device.

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