The disclosure relates to the field of production of thermosetting bonded magnets, and particularly to a device and method for preparing a thermosetting bonded magnet.
Bonded rare earth permanent magnets can be divided into two categories: isotropic bonded magnets and anisotropic bonded magnets. Specifically, the anisotropic bonded magnets can provide excellent magnetic properties by applying an alignment magnetic field in a preparation process, and thus the anisotropic bonded magnets have attracted more and more attention in the field of excellent magnetic devices. In the fields of home appliances, automobiles, office, medical and factory automation, the anisotropic bonded magnets are used to manufacture various micro-motors, magnetic devices, and magnetic medical devices.
The anisotropic bonded magnets are mainly divided into thermosetting magnets and thermoplastic magnets based on a binder used in the preparation process. However, in a preparation process of the thermosetting magnets, the corresponding binder needs to be cured under a constant magnetic field and temperature firstly, then the corresponding binder needs to undergo a secondary curing process, and thus a traditional preparation process of the thermosetting magnets will greatly reduce a yield of the thermosetting magnets. Moreover, the traditional preparation process of the thermosetting magnets only produces a type of bonded magnet which is in a rigid state after curing, so that the type of the bonded magnet cannot be processed into a flexible magnet similar to a thermoplastic magnet, thereby greatly limiting the manufacturing and application schemes of the thermosetting magnets.
In addition, in a preparation process of the thermoplastic magnets, a thermoplastic binder is used to prepare thermoplastic flexible magnets mainly based on rolling. The preparation process involves steps including complex auxiliary configuration, inert powder mixing, formula coating, low-temperature mixing of materials, solvent evaporation, screw mixing or warm kneading, warm rolling, extrusion, and so on. Meanwhile, a solution for providing an alignment magnetic field to achieve magnetic alignment during the rolling or extrusion is very complex and difficult. The preparation process has low production efficiency and high costs, which prevents the widespread use of the anisotropic bonded magnets.
In view of the above, therefore, the disclosure provides a device and method for preparing a thermosetting bonded magnet to solve the above problems.
In order to solve the above problems, the disclosure provides a method and device for preparing a thermosetting bonded magnet to solve the problems as follows: in a preparation process of the thermosetting magnets, the binder needs to be cured under stable temperature and pressure, then the binder needs to undergo a secondary curing process, and thus a traditional preparation process of the thermosetting magnets will greatly reduce a yield of the thermosetting magnets. Moreover, the traditional preparation process of the thermosetting magnets only produces a type of bonded magnet which is in a rigid state after curing, so that the type of the bonded magnet cannot be processed into a flexible magnet similar to a thermoplastic magnet, thereby greatly limiting the manufacturing and application schemes of the thermosetting magnets.
The device for preparing the thermosetting bonded magnet includes a compressed air glue feeding tank and a composite-function mold. A feeding end of the compressed air glue feeding tank is connected to the composite-function mold.
the composite-function mold includes a housing, the housing is disposed at an upper end and a lower end of the composite-function mold, and the housing includes a polytetrafluoroethylene upper cover and a polytetrafluoroethylene lower cover; the polytetrafluoroethylene upper cover and the polytetrafluoroethylene lower cover are respectively disposed at the upper end and the lower end of composite-function mold; a notched internal wall of the polytetrafluoroethylene upper cover and a notched internal wall of the polytetrafluoroethylene lower cover are respectively connected to magnetic iron cores, the polyfluortetraethylene upper cover and the polyfluortetraethylene lower cover together define a cavity therebetween; a rubber ring is disposed between a surface of a corresponding one of the magnetic iron cores and the notched internal wall of the polyfluortetraethylene upper cover; a kneading assembly is disposed in the composite-function mold; and a permanent magnet orientation pole head frame mechanism is disposed on a surface of the composite-function mold.
In an embodiment, the polytetrafluoroethylene upper cover and the polytetrafluoroethylene lower cover are symmetrically distributed along a transverse central axis of the composite-function mold; and the magnetic iron core connected to the notched internal wall of the polytetrafluoroethylene lower wall and the polytetrafluoroethylene lower cover are sealed through a rubber ring when the polytetrafluoroethylene upper cover and the polytetrafluoroethylene lower cover are closed, thereby making a slurry area be in a closed state.
In an embodiment, the kneading assembly comprises a vacuum air hole, a feeding hole, a detachment air hole, film heating plates, temperature controllers, and micro rechargeable batteries; the feeding hole is provided at an end of the composite-function mold connected to the compressed air glue feeding tank; and the vacuum air hole and the detachment air hole are provided sequentially from top to bottom at another end of the composite-function mold, and the vacuum air hole is configured for connecting to a vacuum pump.
In an embodiment, film heating plates are disposed between notched internal walls of the housing and the magnetic iron cores, temperature controllers and micro rechargeable batteries are embedded in the housing; and the film heating plate, the temperature controllers, and the micro rechargeable batteries are electrically connected with each other, and a fixing assembly is disposed in the housing.
In an embodiment, the fixing assembly comprises first screws, second screws, and third screws; each of the first screws is configured to pass through the housing and a corresponding one of the film heating plates to fix the housing, the corresponding one of the film heating plates, and a corresponding one of the magnetic cores; each of the second screws is configured to pass through a temperature control switch on a surface of a corresponding one of the temperature controllers to fix the temperature control switch and a corresponding one of the magnetic cores; and each of the third screws is configured to pass through a thermometer on the surface of the corresponding one of the temperature controllers to fix the thermometer and the housing.
In an embodiment, the permanent magnet orientation pole head frame mechanism comprises left and right brackets, and left and right orientation pole heads; and the left orientation pole head and the right orientation pole head repel each other magnetically.
In an embodiment, a distance adjusting turntable is screwed between opposite ends of the left and right brackets, rare earth permanent magnets with different polarities are respectively disposed on a disc surface of the left orientation pole head and a disc surface of the right orientation pole head, one of the left and right orientation pole heads is an active pole head, a side of the active pole head is provided with a motor, and the other one of the left and right orientation pole heads is a passive pole head.
A method for preparing a thermosetting bonded magnet is provided, and the method includes followings steps S1-S8.
In an embodiment, the black slurry obtained in S2 is a uniformly black viscous slurry without bubbles,
In an embodiment, in S6, during rotating of the composite-function mold (2) and the passive pole head of the left and right orientation pole heads (19), the constant magnetic field and the constant temperature are maintained.
Compared with related art, the disclosure has following beneficial effects.
1—compressed air glue feeding tank; 2—composite-function mold; 3—housing; 4—polytetrafluoroethylene upper cover; 5-polytetrafluoroethylene lower cover; 6—magnetic iron core; 7—cavity; 8—rubber ring; 9—vacuum air hole; 10—feeding hole; 11—detachment air hole; 12—film heating plate; 13—temperature controller; 14—micro rechargeable battery; 15—first screw; 16—second screw; 17—third screw; 18—left and right brackets; 19—left and right orientation pole heads; 20—distance adjusting turntable; 21—rare earth permanent magnet; 22—motor; 23—temperature control switch; 25—vacuum pump.
The following will provide a further detailed description of the embodiments of the disclosure in conjunction with the drawings and embodiments. The following embodiments are used to interrupt disclosure, but cannot be used to limit the scope of the disclosure.
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The composite-function mold 2 includes a housing 3, the housing 3 is disposed at an upper end and a lower end of the composite-function mold 2, and the housing 3 includes a polytetrafluoroethylene upper cover 4 and a polytetrafluoroethylene lower cover 5; the polytetrafluoroethylene upper cover 4 and the polytetrafluoroethylene lower cover 5 are respectively disposed at the upper end and the lower end of composite-function mold 2, a notched internal wall of the polytetrafluoroethylene upper cover 4 and a notched internal wall of the polytetrafluoroethylene lower cover 5 are respectively connected to magnetic iron cores 6, the polyfluortetraethylene upper cover 4 and the polyfluortetraethylene lower cover 5 together define a cavity 7, a rubber ring 8 is disposed between a surface of a corresponding one of the magnetic iron cores 6 and the notched internal wall of the polyfluortetraethylene upper cover 4, a kneading assembly is disposed in the composite-function mold 2, and a permanent magnet orientation pole head frame mechanism is disposed on a surface of the composite-function mold 2.
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A method for preparing a thermosetting bonded magnet includes following steps S1-S8. In the step S1, powders and a silica gel binder are selected as raw materials to prepare a magnet slurry of a thermosetting bonded magnet; the powders include a HDDR neodymium-iron-boron magnetic powder, a samarium-iron-nitrogen magnetic powder, and a graphene powder; and the silica gel binder include a first silica gel, a second silica gel, and a curing agent. 150-mesh HDDR neodymium-iron-boron magnetic powder and the samarium-iron-nitrogen magnetic powder with an average particle size of 2.6 micrometers, and the graphene powder are weighted in a loose volume ratio of 4:1:0.3 to obtain weighted powders for standby; a mass of the silica gel binder is determined according to a mass ratio of 89:11 between a total mass of the powders and the mass of the silica gel binder. In the step S2, A first silica gel, a second silica gel, and a curing agent are mixed to obtain the silica gel binder, the silica gel binder and the weighted powders are put into a planetary vacuum deaeration mixer for mixing in a non-contact manner for 5 minutes to obtain a uniformly black viscous slurry without bubbles (i.e., the magnet slurry), then the magnet slurry is performed with the steps S3-S6 including grinding, storing, feeding, and kneading. Specifically, the preset temperature in the kneading of step S6 is 130° C., both rotation speeds of the composite-function mold 2 and the passive pole head are 20 revolutions per minute (rpm), and the composite-function mold 2 and the passive pole head rotate for about 40 minutes, then the motor 22 is turned off, a constant magnetic field and a constant temperature of the composite-function mold 2 are maintained for 1 hour, and the composite-function mold 2 is taken out between the left and right brackets 18 to continue maintaining the constant temperature for 1 hour. Then the composite-function mold 2 is performed with standing of step S7, thereby obtaining a flexible magnetic sheet with a diameter of 50 mm and a thickness of 12 mm. The magnetic strength of the magnetic sheet (i.e., the thermosetting bonded magnet) tested by a magnetometer is 2150 gauss.
A method for preparing a thermosetting bonded magnet includes following step S1-S8. In the step S1, powders and a silica gel binder are selected as raw materials to prepare magnet slurry of a thermosetting bonded magnet; the powders include a neodymium-iron-boron magnetic powder, a samarium-iron-nitrogen magnetic powder, and a molybdenum disulfide powder; and the silica gel binder include a first silica gel, a second silica gel, and a curing agent. 200-mesh HDDR neodymium-iron-boron magnetic powder and the samarium-iron-nitrogen magnetic powder with an average particle size of 2.6 micrometers, and the molybdenum disulfide powder are weighted in a loose volume ratio of 3:1:0.5 to obtain weighted powders for standby; a mass of the silica gel binder is determined according to a mass ratio of 85:15 between a total mass of the powders and the mass of the silica gel binder. In the Step S2, a first silica gel, a second silica gel, and a curing agent are mixed to obtain the silica gel binder, the silica gel binder and the weighted powders are put into a planetary vacuum deaeration mixer for mixing in a non-contact manner for 5 minutes to obtain a uniformly black viscous slurry without bubbles (i.e., the magnet slurry). Then the magnet slurry is performed with steps S3-S6 including grinding, storing, feeding, and kneading. Specifically, the preset temperature in the kneading of step S6 is 110° C., both rotation speeds of the composite-function mold 2 and the passive pole head are 30 rpm, and the composite-function mold 2 and the passive pole head rotate for about 40 minutes, then the motor 22 is turned off, a constant magnetic field and a constant temperature of the composite-function mold 2 are maintained for 2 hour, and the composite-function mold 2 is taken out between the left and right brackets 18 to continue maintaining the constant temperature for 1 hour. Then the composite-function mold 2 is performed with standing of step S7, thereby obtaining a flexible magnetic column with a diameter of 20 mm and a thickness of 15 mm. In the testing of step S8, the magnetic strength of the magnetic column tested by a magnetometer is 1028 gauss
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The embodiments of the disclosure are provided to facilitate describing the disclosure. Although embodiments of the disclosure have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as a limitation of the disclosure. Ordinary those skilled in the art can make changes, modifications, substitutions, and modifications to the above embodiments within the scope of the disclosure.
Number | Date | Country | Kind |
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2022112146704 | Sep 2022 | CN | national |