JP5760439B2 - Slurry supply device and coating device - Google Patents

Description

  The present invention relates to a slurry supply device and a coating device for applying a slurry containing a rare earth compound to a sintered body when manufacturing a rare earth sintered magnet.

  A rare earth sintered magnet having a composition of R—Fe—B (R is a rare earth element) is a magnet having excellent magnetic properties. As a method for producing such a rare earth magnet, there is a method of applying a heat treatment after applying a slurry containing a rare earth to a sintered body. For example, in Patent Document 1, in a state where a powder containing rare earth elements including Y and Sc is present on the surface of the sintered magnet body, the sintered magnet body and the powder are below the sintering temperature of the sintered magnet body. Disclosed is a method for producing a rare earth permanent magnet, characterized in that a sintered magnet body absorbs a rare earth element contained in the powder by heat treatment in a vacuum or an inert gas at a temperature for 1 minute to 100 hours. Has been. Patent Document 1 describes a method of putting a sintered magnet body into a slurry in which the powder is dispersed in water or an organic solvent as a method for attaching a powder containing a rare earth element to the sintered magnet body. .

JP 2008-147634 A

  In a method in which a sintered body is charged into a slurry in which powder is dispersed in water or an organic solvent, the thickness of the slurry applied to the sintered body varies depending on the position of the surface, and variations may occur. Thus, when the thickness of the slurry applied to the sintered body varies, the amount of the rare earth compound adhering to the sintered body also varies depending on the position of the sintered body. As a result, the performance of the magnet manufactured by the subsequent heat treatment also varies. For example, the surface magnetic flux varies.

  The present invention has been made in view of the above, and reduces the variation in the thickness of the slurry adhering to the surface of the sintered body depending on the location when a slurry containing a rare earth compound is applied to the sintered body. With the goal.

  In order to solve the above-described problems and achieve the object, the present inventors have conducted extensive research on applying a slurry containing a rare earth compound to the surface of the sintered body and attaching the rare earth compound to the surface of the sintered body. Repeated. As a result, it is possible to discharge (spill out) the slurry from the plurality of discharge ports to a rotating sintered body using a slurry supply apparatus having a plurality of discharge ports for discharging the slurry containing the rare earth compound. It was found useful for reducing the variation in the thickness of the slurry depending on the location. The present invention relates to a slurry supply apparatus having a plurality of discharge ports for discharging (outflowing) a slurry containing a rare earth compound.

In order to solve the above-described problems and achieve the object, the present invention is surrounded by a plurality of slurry outflow passages arranged at a predetermined interval and allowing a slurry containing a rare earth compound to pass therethrough and a plurality of wall surfaces. were together store the slurry in the cavity, opening a plurality of the slurry outflow passage to said cavity, a wall of the slurry outlet passage of several are located at both ends of the direction in which the sequence is one of two curved surfaces, respectively A slurry holding part having a shape connected in a plane, and slurry introduction for opening the slurry holding part and introducing the slurry into the slurry holding part from a direction intersecting the direction in which the slurry passes through the slurry outflow passage A passage crossing the slurry introduction passage and connected to the slurry introduction passage, the slurry being introduced into the slurry introduction passage Seen containing a slurry supply passage for flowing the in the direction of the slurry outflow passage the slurry passes, the single plane is positioned between the two curved surfaces, the two curved surfaces are concave, the One slurry introduction passage is opened at a central portion in a direction in which the plurality of slurry outflow passages are arranged .

  In this slurry supply device, a curved portion is provided between the slurry supply passage and the slurry introduction passage, that is, in the slurry flow path. Then, when the slurry passes through the slurry supply passage and the slurry introduction passage, the flow rate of the slurry is reduced at the bent portion, and then the slurry is introduced into the cavity. In this way, the flow rate of the slurry discharged from the slurry outlet passage in the central portion is suppressed in the cavity because the increase in the flow velocity of the slurry is suppressed in the central portion in the direction in which the plurality of slurry outlet passages are arranged. Can be prevented from increasing. Moreover, this slurry supply apparatus makes the wall surface in a cavity into the shape where two curved surfaces were connected by one plane on both sides of the direction where a some slurry outflow channel | path is arranged. By doing in this way, since the retention of the slurry on both sides in the direction in which the plurality of slurry outflow passages are arranged is suppressed, it is possible to suppress a decrease in the flow rate of the slurry discharged from the slurry outflow passages on both sides. By these actions, this slurry supply apparatus can suppress variation in the flow rate of the slurry between the plurality of slurry outflow passages. As a result, in the sintered body to which the slurry is applied by this slurry supply device, variation in the thickness of the slurry depending on the place is suppressed in one sintered body.

Before SL slurry introducing passage, you one opening in the central portion in the direction in which the plurality of the slurry outlet passage is arranged. In this way, since the slurry can be distributed in a balanced manner on both sides in the direction in which the plurality of slurry outflow passages are arranged, it is possible to effectively reduce the variation in the flow rate of the slurry between the plurality of slurry outflow passages. When slurry is supplied into the cavity from a plurality of openings, the slurry supplied from the openings collides and stays in the cavity, resulting in a large variation in the flow rate of the slurry between the plurality of slurry outflow passages. Since this slurry supply device can avoid the collision of the slurry in the cavity by providing one opening of the slurry introduction passage in the cavity, it is possible to prevent the slurry from flowing between the plurality of slurry outflow passages. The variation in the flow rate of the slurry can be suppressed.

  As a desirable aspect of the present invention, it is preferable that an angle formed between the slurry introduction passage and the slurry supply passage is within 90 ° ± 10 °. In this way, it is possible to effectively reduce the flow rate of the slurry passing through the bent portion formed between the slurry supply passage and the slurry introduction passage. As a result, in the cavity, it is possible to effectively suppress an increase in the flow rate of the slurry in the central portion in the direction in which the plurality of slurry outflow passages are arranged. It can suppress more reliably that a flow volume increases.

  As a desirable aspect of the present invention, in the direction in which the slurry passes through the slurry outflow passage, the dimension of the plane is preferably 2/5 or more and 9/10 or less of the dimension of the cavity. In this way, the retention of the slurry on both sides in the direction in which the plurality of slurry outflow passages are arranged can be more reliably suppressed. As a result, it is possible to more reliably suppress a decrease in the flow rate of the slurry discharged from the slurry outflow passages on both sides, and to more effectively suppress variations in the flow rate of the slurry discharged from the plurality of slurry outflow passages.

  As a desirable mode of the present invention, the cavity is an outer side connected to one of the two curved surfaces on the outer side of each of the outermost slurry outlet passages in the direction in which the plurality of slurry outlet passages are arranged. A plane is preferably provided. This outer plane causes an excessive increase in the flow rate of the slurry flowing out from the slurry outflow passages arranged outside in the direction in which the plurality of slurry outflow passages are arranged, particularly from the respective slurry outflow passages arranged at the outermost side. Can be suppressed.

  As a desirable mode of the present invention, each of the outer flat surfaces has a distance from the outermost slurry outflow passage to one of the two curved surfaces in the direction in which the plurality of slurry outflow passages are arranged is 1 mm or more and 10 mm or less. Preferably there is. If the said distance is 1 mm or more, it can suppress more reliably that the flow rate of the slurry which flows out from the slurry outflow path arrange | positioned on the outer side of the direction where a some slurry outflow path is arranged increases excessively. Further, if the distance is 10 mm or less, even when a slurry having high thixotropy is used, clogging of the slurry outflow passage hardly occurs.

  In order to solve the above-described problems and achieve the object, the present invention includes a holding unit that contacts and holds the sintered body, a rotating unit that rotates the sintered body, and the slurry supply device. The coating device is characterized in that the slurry flows out from the slurry outflow passage of the slurry supply device toward the sintered body while rotating the sintered body by the rotating means.

  In this coating apparatus, the slurry containing the rare earth compound is caused to flow out from the slurry outlet passage of the slurry supply device toward the sintered body rotating about an axis parallel to the longitudinal direction of the sintered body, and the slurry is sintered. Apply to the body. At this time, the direction in which the plurality of slurry outflows are arranged and the longitudinal direction of the sintered body are made substantially parallel. As described above, the slurry flow is discharged to the rotating sintered body by the slurry supply device described above, and the slurry is applied to the surface of the sintered body, so that the variation in the thickness of the slurry in the arrangement direction of the slurry outflow passage can be reduced. It is suppressed. Further, by applying the slurry while rotating the magnetic body, the thickness of the slurry applied to the surface of the magnetic body can be made uniform.

  According to the present invention, when a slurry containing a rare earth compound is applied to a sintered body, the thickness of the slurry attached to the surface of the sintered body can be reduced from varying depending on the location.

FIG. 1 is a schematic diagram illustrating a schematic configuration of a magnet manufacturing apparatus having a coating mechanism (coating apparatus) according to the present embodiment. FIG. 2 is a schematic diagram illustrating a schematic configuration of a coating mechanism included in the magnet manufacturing apparatus illustrated in FIG. 1. FIG. 3 is a side view of the nozzle head according to the present embodiment. FIG. 4 is a front view of the nozzle head according to the present embodiment. FIG. 5 is a bottom view of the nozzle head according to the present embodiment. 6 is a view taken in the direction of arrows XX in FIG. 7 is a view taken in the direction of arrows YY in FIG. FIG. 8A is a front view illustrating a schematic configuration of the rotation holding unit according to the present embodiment. FIG. 8-2 is a plan view illustrating a schematic configuration of the rotation holding unit according to the present embodiment. FIG. 9A is an explanatory diagram for explaining the operation of the coating mechanism according to the present embodiment. FIG. 9-2 is an explanatory diagram for explaining the operation of the coating mechanism according to the present embodiment. FIG. 10 is a flowchart showing a processing procedure when a rare earth sintered magnet is manufactured by the magnet manufacturing apparatus according to the present embodiment. FIG. 11 is an explanatory diagram showing the arrangement of the ejection ports 81 included in the nozzle head used for the evaluation. FIG. 12 is a schematic diagram illustrating an internal structure of a nozzle head according to a comparative example. FIG. 13 is a schematic diagram illustrating an internal structure of a nozzle head according to a comparative example. FIG. 14 is a plan view showing a position where the thickness of the slurry is measured.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

  FIG. 1 is a schematic diagram illustrating a schematic configuration of a magnet manufacturing apparatus having a coating mechanism (coating apparatus) according to the present embodiment. As shown in FIG. 1, the magnet manufacturing apparatus 10 includes a sintered body supply mechanism 12, a coating mechanism 14, a drying mechanism 16, a heat treatment mechanism 18, a transport mechanism 20, and a control device 22. The control device 22 is a mechanism that controls the operation of each unit. The sintered body supply mechanism 12 has a plurality of sintered bodies 34 and supplies one of the sintered bodies 34 to the transport mechanism 20. The sintered body 34 is obtained by sintering a molded body obtained by molding raw material powder.

  The coating mechanism 14 applies a slurry 35 containing a rare earth compound to the sintered body 34 supplied from the sintered body supply mechanism 12 and transported by the transport mechanism 20. The rare earth compound contained in the slurry 35 and applied to the sintered body 34 includes a rare earth element R (R is a rare earth element that always contains at least one of Dy and Tb), R hydride, R oxide, R fluoride. Fluoride, RT alloy (T is a transition metal element), RT hydride, RT oxide, RTB alloy (B is boron), RTB hydride, RTB oxide can be used.

  The slurry 35 preferably contains a resin. By doing in this way, the adhesiveness of the rare earth compound with respect to the sintered compact 34 can be improved. The resin used for the slurry 35 is not particularly limited, and for example, polyurethane resin, polyester resin, butyral resin, acrylic resin, phenol resin, epoxy resin, cellulose resin and the like are used. Moreover, the solvent used for the slurry 35 will not be specifically limited if resin can be melt | dissolved. The viscosity of the slurry 35 is about 30 cp, for example. Details of the coating mechanism 14 will be described later.

  The drying mechanism 16 dries the slurry 35 applied to the sintered body 34 by the application mechanism 14. Specifically, the drying mechanism 16 volatilizes the solvent contained in the slurry 35. In the present embodiment, various drying methods can be applied to the drying mechanism 16. For example, a method of drying the slurry 35 by heating and blowing can be applied to the drying mechanism 16. The drying mechanism 16 may dry the sintered body 34 coated with the slurry 35 by natural drying. In the present embodiment, the drying mechanism 16 dries the slurry 35 applied to the sintered body 34 while rotating the sintered body 34.

  The heat treatment mechanism 18 heat-treats the sintered body 34 after the slurry 35 is dried by the drying mechanism 16. Specifically, the heat treatment mechanism 18 holds the sintered body 34 after the slurry 35 is dried at a predetermined temperature for a predetermined time.

  The transport mechanism 20 transports the sintered body 34. For example, in the present embodiment, the transport mechanism 20 transports the sintered body 34 supplied from the sintered body supply mechanism 12 to the coating mechanism 14, or heats the sintered body 34 dried by the drying mechanism 16. Or transport to. Various means can be applied to the transport mechanism 20. For example, a belt conveyor or a robot arm can be used as the transport mechanism 20. In this embodiment, the coating mechanism 14 carries the sintered body 34 from the coating mechanism 14 to the drying mechanism 16. Next, the coating mechanism 14 will be described.

  FIG. 2 is a schematic diagram illustrating a schematic configuration of a coating mechanism included in the magnet manufacturing apparatus illustrated in FIG. 1. In the present embodiment, the case where a plate-like sintered body 34 is used will be described, but the shape of the sintered body 34 is not limited to this. The application mechanism 14 includes an application unit 30 that applies the slurry 35 to the sintered body 34, and a rotation holding unit 32 that holds the sintered body 34 and rotates the sintered body 34.

  The application unit 30 discharges the slurry 35 toward the sintered body 34 and applies the slurry 35 to the surface of the sintered body 34, supplies the slurry 35 to the application unit 40, and supplies the slurry 35 from the application unit 40. And a concentration adjusting unit 44 for adjusting the concentration of the slurry 35 circulated in the slurry circulating unit 42. The application unit 40 includes a nozzle head 80 as a slurry supply device and a tray 52. The nozzle head 80 has a plurality of discharge ports 81. The nozzle head 80 stores the slurry 35 supplied from the slurry circulating unit 42 inside, and then discharges (discharges or flows out) the slurry 35 from the plurality of discharge ports 81 toward the sintered body 34. The slurry 35 discharged from the plurality of discharge ports 81 becomes a plurality of slurry flows, adheres to the sintered body 34, and is applied to the surface thereof. Details of the structure of the nozzle head 80 will be described later.

  The tray 52 is a slurry recovery unit disposed on the vertical direction side (lower side) of the nozzle head 80 and is discharged from the discharge port 81 and does not adhere to the sintered body 34, that is, is applied to the sintered body 34. The missing slurry 35 is collected. The tray 52 has a side surface 52S that is an inclined surface. A recovery port 52H for recovering the slurry 35 is formed on the bottom surface 52B of the tray 52. The slurry 35 that has flowed out of the tray 52 flows from the side surface 52S toward the bottom surface 52B, and is collected by the slurry circulation unit 42 from the collection port 52H of the bottom surface 52B.

  The slurry circulating unit 42 includes a slurry tank 54, a stirrer 56, and a pump 58. The slurry tank 54 is a tank that stores the slurry 35, and a certain amount of the slurry 35 is stored therein. The slurry tank 54 is connected to the nozzle head 80 via a pipe 55a, and is connected to the tray 52 via a pipe 55b. The stirrer 56 is a device that stirs the slurry 35 in the slurry tank 54. When the agitator 56 agitates the slurry 35 in the slurry tank 54, precipitation of rare earth compounds and the like is suppressed, and the concentration of the slurry 35 in the slurry tank 54 is kept uniform.

  The pump 58 is a drive source for circulating the slurry 35 stored in the slurry tank 54 between the coating unit 40 and the slurry circulation unit 42 of the coating unit 30. The pump 58 supplies the slurry 35 stored in the slurry tank 54 to the nozzle head 80 from the pipe 55a. In the present embodiment, the slurry 35 is circulated between the application unit 40 and the slurry circulation unit 42. However, in the present embodiment, the slurry 35 released by the nozzle head 80 is not collected and reused. It is not excluded to avoid.

  The concentration adjusting unit 44 includes a solvent tank 64 and a pump 66. The solvent tank 64 is a container for storing the solvent (solvent) contained in the slurry 35. The solvent tank 64 is connected to the slurry tank 54 via a pipe 65. The pump 66 is provided in the pipe 65 and supplies the solvent stored in the solvent tank 64 to the slurry tank 54. The concentration adjusting unit 44 drives the pump 66 to supply the solvent stored in the solvent tank 64 to the slurry tank 54, and the concentration of rare earth compounds contained in the slurry 35 in the slurry tank 54 and the pipe 55 a (hereinafter, referred to as “concentration”). The slurry concentration) is kept within a certain range. By setting the slurry concentration within a certain range, the ratio of the solvent (solvent) and the solute (rare earth compound) can be maintained within a certain range. In addition, it is preferable that the concentration adjusting unit 44 further includes a concentration measuring unit that measures the slurry concentration. The concentration adjusting unit 44 can measure the density of the slurry 35 in the slurry tank 54 or the circulated slurry 35 as appropriate by having a concentration measuring means. The concentration adjusting unit 44 can appropriately adjust the slurry concentration to a predetermined value based on the measurement result.

  With the structure described above, the coating unit 30 of the coating mechanism 14 discharges the slurry 35 toward the sintered body 34 from the plurality of discharge ports 81 included in the nozzle head 80 of the coating unit 40. In this way, the application unit 30 applies the slurry 35 to the surface of the sintered body 34. The slurry 35 not received by the sintered body 34 but received by the receiving tray 52 is collected from the pipe 55b to the slurry tank 54. The recovered slurry 35 is supplied again to the nozzle head 80 by the slurry circulating unit 42 and discharged from the discharge port 81. Next, the structure of the nozzle head 80 will be described in more detail.

  FIG. 3 is a side view of the nozzle head according to the present embodiment. FIG. 4 is a front view of the nozzle head according to the present embodiment. FIG. 5 is a bottom view of the nozzle head according to the present embodiment. As shown in FIG. 3, the nozzle head 80 is a rectangular parallelepiped structure. The nozzle head 80 has a structure in which the first member 80F and the second member 80R are combined at the mating portion 80B and, for example, the first member 80F and the second member 80R are fastened by fastening means such as screws. The matching unit 80B divides the discharge port 81 into two. The nozzle head 80 is not limited to such a two-divided structure. For example, the nozzle head 80 may have a divided structure in which the discharge port 81 is not divided into two or a three-divided structure.

  As shown in FIGS. 3 and 4, the nozzle head 80 has a cavity 83 surrounded by a plurality of wall surfaces 84, 84, 85, 86, 87, 87. The cavity 83 is a substantially rectangular parallelepiped cavity surrounded by six wall surfaces 84, 84, 85, 86, 87, 87. Of the six wall surfaces 84, 84, 85, 86, 87, 87 constituting the cavity 83, the wall surface 84 and the wall surface 84 face each other, the wall surface 87 and the wall surface 87 face each other, and the wall surface 85 and the wall surface 86 face each other. To do. The wall surfaces 84, 84, 85, 86 are all flat surfaces. As will be described later, the wall surfaces 87 and 87 have a shape in which two curved surfaces are connected by a single plane.

  A slurry introduction passage 88 is connected to the cavity 83. The slurry introduction passage 88 is connected to the slurry supply passage 89. The slurry supply passage 89 is connected to the pipe 55a shown in FIG. With such a structure, in the nozzle head 80, the slurry flows into the cavity 83 from the pipe 55 a through the slurry supply passage 89 and the slurry introduction passage 88. The cavity 83 accumulates and holds the inflowing slurry.

  As shown in FIG. 5, the plurality of discharge ports 81 are arranged at a predetermined interval (preferably arranged in a line) on one surface of the nozzle head 80 (the surface facing the surface where the slurry supply passage 89 opens). . In the present embodiment, the discharge ports 81 are arranged at equal intervals. By doing in this way, the in-plane dispersion | variation in the thickness of the slurry apply | coated to the surface of a sintered compact can be suppressed. The discharge ports 81 are arranged in a line between the first member 80F and the second member 80R, more specifically, on the matching portion 80B of both. The plurality of discharge ports 81 are all connected to the cavity 83 and discharge the slurry stored in the cavity 83. In the present embodiment, the shape of the opening of the discharge port 81 is a circle, but the shape is not limited to a circle.

  6 is a view taken in the direction of arrows XX in FIG. The figure shows a state in which the first member 80R of the nozzle 80 is viewed from the cavity 83 side. 7 is a view taken in the direction of arrows YY in FIG. The nozzle head 80 includes a slurry outflow passage 82, a slurry holding portion, a slurry introduction passage 88, and a slurry supply passage 89. The slurry outflow passages 82 are arranged in a line at predetermined intervals to allow the slurry containing the rare earth compound to pass therethrough and outflow. The nozzle head 80 has a plurality of slurry outflow passages 82. In the present embodiment, the nozzle head 80 has eleven slurry outflow passages 82, but the number of slurry outflow passages 82 is not limited to this. One end of the slurry outflow passage 82 opens to the surface (lower surface 80PB) of the nozzle head 80 to serve as the discharge port 81, and the other end opens to the cavity 83 to serve as the slurry inlet.

  A slurry introduction passage 88 shown in FIG. 3 is opened in the cavity 83 to form a slurry introduction port 88H. The slurry inlet 88H is open to the wall surface 86 shown in FIG. The slurry flows into the cavity 83 from the slurry inlet 88H. Then, the slurry flowing into the cavity 83 from the slurry introduction port 88H flows toward both sides of the direction in which the plurality of slurry outflow passages 82 are arranged (the direction indicated by the arrow W in FIG. 6, hereinafter referred to as the width direction), It is discharged from the plurality of slurry outflow passages 82 to the outside of the cavity 83.

  If the wall surfaces 87, 87 on both sides in the width direction of the cavity 83 are, for example, one curved surface or one plane, the flow rate of the slurry discharged from each of the plurality of slurry outflow passages 82 arranged in the width direction. Variation occurs. Specifically, the flow rate of the slurry outflow passages 82 on both sides in the width direction is small, and the flow rate of the slurry outflow passages 82 in the center portion in the width direction is large. Then, variation occurs in the amount of slurry supplied to the sintered body, and variation occurs in the thickness of the applied slurry layer in the sintered body after the slurry is dried. As a result, the obtained magnet may have variations in magnetic characteristics.

  This is because when the wall surfaces 87, 87 on both sides in the width direction are one curved surface, the slurry circulates (convects) along the curved surface and stays in the vicinity of the wall surfaces 87, 87. This is considered to be the cause of the variation in the flow rate between the passages 82. Further, when the wall surfaces 87 and 87 on both sides in the width direction are one plane, the wall surfaces 84 and 84 and the wall surface 87 are orthogonal to each other. For this reason, as a result of the connection portion between the wall surfaces 84 and 84 and the wall surface 87 being at right angles, the slurry circulates (convects) in this portion and stays in the vicinity of the wall surfaces 87 and 87. This is considered to be the cause of the flow rate variation between the two 82.

  In the present embodiment, the cavity 83 has a shape in which the wall surfaces 87 and 87 on both sides in the width direction, that is, the direction in which the plurality of slurry outflow passages 82 are arranged, connect two curved surfaces 87Ra and 87Rb with one flat surface 87S. It is. The cavity 83 formed in this way corresponds to the slurry holding part. By doing so, the circulation of the slurry flowing from the slurry introduction port 88H toward the both sides in the width direction is suppressed by the plane 87S connecting the curved surfaces 87Ra and 87Rb. Then, the slurry is suppressed from staying in the vicinity of the wall surfaces 87, 87, so that the slurry flow in the cavity 83 is stabilized. And the flow volume fall of the slurry which flows out from the slurry outflow passage 82 of the width direction both sides is suppressed. As a result, the nozzle head 80 suppresses variations in the flow rate of the slurry between the plurality of slurry outflow passages 82, thereby suppressing variations in the amount of slurry supplied to the sintered body and firing after the slurry is dried. In the bonded body, variation in the thickness of the applied slurry is reduced. For this reason, the obtained magnet suppresses the dispersion | variation in a magnetic characteristic.

  In the direction in which the slurry passes through the slurry outflow passage 82 (the direction in which the slurry outflow passage 82 is formed in the nozzle head 80, hereinafter referred to as the height direction), the dimensions (plane length) h of the planes 87S and 87S are the height. It is preferably 2/5 or more and 9/10 or less of the dimension (cavity height) H of the cavity in the direction. That is, it is preferable that 2/5 ≦ h / H ≦ 9/10. In this way, since the circulation of the slurry on the wall surfaces 87, 87 on both sides in the width direction can be more effectively suppressed, the variation in the flow rate of the slurry between the plurality of slurry outflow passages 82 can be further reduced. As a result, the variation in the thickness of the slurry applied to the sintered body can be further reduced. Note that if the radius of the curved surface 87Ra is ra and the radius of the curved surface 87Rb is rb, H = ra + h + rb.

  The cavity height H is preferably 5 mm or more and 30 mm or less. By setting the cavity height H to 5 mm or more, a space for the slurry to flow in the cavity 83 can be secured, so that the flow of the slurry in the cavity 83 can be stabilized. Further, by setting the cavity height H to 30 mm or less, the slurry can be filled in the cavity 83 even when the flow rate of the slurry flowing in the pipe 55a shown in FIG. As a result, the possibility that the slurry in the cavity 83 entrains air can be reduced, and the slurry can be stably discharged from the slurry outflow passage 82. And the dispersion | variation in the thickness of the slurry apply | coated to the sintered compact can be reduced more.

  The cavity 83 has an outer flat surface 84S connected to one of the two curved surfaces 87Ra and 87Rb (the curved surface 87Ra in the present embodiment) outside the respective slurry outflow passages 82o and 82o arranged on the outermost side in the width direction. Is provided. The cavity 83 has the outer flat surface 84S, thereby suppressing an excessive increase in the flow rate of the slurry flowing out from the slurry outflow passage 82 on the outer side in the width direction, in particular, the respective slurry outflow passages 82o and 82o arranged on the outermost side. it can.

  Each of the outer planes 84S and 84S is a distance (outer plane length) Ls from the outermost slurry outflow passages 82o and 82o in the width direction to one of the two curved surfaces 87Ra and 87Rb (the curved surface 87Ra in this embodiment). Is preferably 1 mm or more and 10 mm or less. By setting the outer plane length Ls to 1 mm or more, it is possible to effectively suppress an excessive increase in the flow rate of the slurry flowing out from the slurry outflow passage 82 on the outer side in the width direction. In addition, by setting the outer plane length Ls to 10 mm or less, the occurrence of slurry accumulation on both sides in the width direction of the cavity 83 can be suppressed. By reducing the slurry pool, it is possible to suppress a decrease in the flow rate of the slurry flowing out from the slurry outflow passage 82 on the outer side in the width direction. If the outer plane length Ls is set to 10 mm or less, it is preferable to use a slurry having high thixotropy because clogging of the slurry outflow passage 82 can be suppressed.

  In the present embodiment, the radius ra of the curved surface 87Ra and the radius rb of the curved surface 87Rb are the same size, but they may be different. By adjusting ra and rb, there is a possibility that the circulation of the slurry on the wall surfaces 87 and 87 on both sides in the width direction can be further reduced. Moreover, ra and rb are preferably 1 mm or more and 3 mm or less. If ra and rb are 1 mm or more, the occurrence of slurry accumulation on both sides in the width direction of the cavity 83 can be suppressed. By reducing the slurry pool, a decrease in the flow rate of the slurry flowing out from the slurry outflow passage 82 on the outer side in the width direction can be suppressed. Moreover, if ra and rb are 3 mm or less, the circulation of the slurry in the vicinity of the wall surfaces 87 on both sides in the width direction of the cavity 83 can be suppressed. As a result, a decrease in the flow rate of the slurry flowing out from the slurry outflow passage 82 on the outer side in the width direction can be suppressed.

  3 is preferably opened at the center of the cavity 83 in the width direction. In the present embodiment, the slurry introduction passage 88 is opened at the position of the slurry outflow passage 82c at the center in the width direction. Assuming that the dimension of the cavity 83 in the width direction is Wa, the axis Zy passing through the opening center of the slurry introduction passage 88 is at a position of Wa / 2 from the planes 87S and 87S of the wall surfaces 87 and 87 of the cavity 83, respectively. In this way, since the slurry can be distributed in a balanced manner on both sides in the width direction, the variation in the flow rate of the slurry between the plurality of slurry outflow passages 82 can be effectively reduced. In the present embodiment, another axis Zx passing through the center of opening of the slurry introduction passage 88 is at the center of the cavity height H, but the position of Zx is not limited to this.

  Further, if two openings of the slurry introduction passage 88 are provided in the cavity 83, the slurries collide with each other between the openings, and retention occurs. As a result, the slurry flow rate varies among the plurality of slurry outflow passages 82. In the present embodiment, since the slurry introduction passage 88 has an opening in the cavity 83 as one slurry introduction port 88H, retention due to the collision of the slurry in the cavity 83 can be avoided. The variation in the flow rate of the slurry can be suppressed.

  As shown in FIG. 7, the slurry introduction passage 88 has a slurry holding portion (cavity 83) from a direction intersecting with a direction in which the slurry passes through the slurry outflow passage 82 (a direction parallel to the passage axis Zn of the slurry outflow passage 82). Into the slurry. When the passage axis of the slurry introduction passage 88 is Zs1, Zn and Zs1 intersect. In the present embodiment, the angle α formed by Zn and Zs1 is 90 degrees. That is, in the present embodiment, the slurry introduction passage 88 introduces the slurry into the slurry holding portion from a direction orthogonal to the direction in which the slurry passes through the slurry outflow passage 82.

  A slurry supply passage 89 is connected to the slurry introduction passage 88. The slurry supply passage 89 allows the slurry to flow into the slurry introduction passage 88. The slurry supply passage 89 intersects with the slurry introduction passage 88. That is, if the passage axis of the slurry supply passage 89 is Zs2, Zs1 and Zs2 intersect. In the present embodiment, Zs1 and Zs2 are orthogonal to each other. That is, the angle β formed by both is 90 degrees.

  By doing so, a bent portion can be provided between the slurry supply passage 89 and the slurry introduction passage 88. Since the slurry that has passed through the slurry supply passage 89 bends at the bent portion when flowing into the slurry introduction passage 88, the flow velocity when flowing into the cavity 83 is reduced. In the cavity 83, the flow rate of the slurry becomes the highest at the portion where the slurry introduction port 88H is opened. For this reason, the flow rate of the slurry passing through the slurry outflow passage 82 in the vicinity of the slurry introduction port 88H becomes the fastest, so that the dispersion of the slurry flow rate among the plurality of slurry outflow passages 82 becomes large.

  In the present embodiment, an increase in the flow rate of the slurry in the portion where the slurry introduction port 88H is opened by the bent portion can be suppressed. As a result, the variation in the slurry flow rate among the plurality of slurry outflow passages 82 can be further reduced. The angle β formed by the passage axis Zs1 of the slurry introduction passage 88 and the passage axis Zs2 of the slurry supply passage 89 is preferably in the range of 90 ° ± 10 °. In this way, the flow rate of the slurry flowing into the cavity 83 can be effectively reduced, and the variation in the slurry flow rate among the plurality of slurry outflow passages 82 can be further reduced. The positive direction is the direction when the passage axis Zs2 of the slurry supply passage 89 is inclined toward the passage axis Zn of the slurry outflow passage 82, and the negative direction is the passage axis Zs2 of the slurry supply passage 89. This is the direction in the case of inclining away from the passage axis Zn.

  The angle formed by the passage axis Zn of the slurry outflow passage 82 and the passage axis Zs1 of the slurry introduction passage 88 is preferably 90 ° ± 30 °, more preferably 90 ° ± 10 °, and further preferably 90 ° (tolerance and manufacturing error). Included). The positive direction is the direction when the passage axis Zs1 of the slurry introduction passage 88 is inclined toward the discharge port 81 of the slurry outflow passage 82, and the negative direction is the passage axis Zs1 of the slurry introduction passage 88. This is the direction in the case of tilting away from the discharge port 81.

  When the passage axis Zs2 of the slurry supply passage 89 is parallel to the passage axis Zn of the slurry outflow passage 82 and the passage axis Zs1 of the slurry introduction passage 88 is inclined in the + direction, β becomes an obtuse angle. For this reason, when the slurry flows from the slurry supply passage 89 to the slurry introduction passage 88, it bends at a steeper angle than 90 degrees. For this reason, the slurry that has passed through the bent portion between the slurry supply passage 89 and the slurry introduction passage 88 flows into the cavity 83 in a state where the flow velocity is further reduced. As a result, an increase in the flow rate of the slurry in the portion where the slurry introduction port 88H is open can be further suppressed, so that variations in the flow rate of the slurry among the plurality of slurry outflow passages 82 can be further reduced. Further, when the passage axis Zs1 of the slurry introduction passage 88 is inclined in the + direction, when the discharge port 81 of the slurry outflow passage 82 is directed in the vertical direction, the slurry introduction passage 88 is directed upward (a direction opposite to the vertical direction). For this reason, the flow rate of the slurry passing through the slurry introduction passage 88 is reduced by the action of gravity. Then, the flow rate of the slurry that has passed through the slurry introduction passage 88 decreases. As a result, an increase in the flow rate of the slurry in the portion where the slurry introduction port 88H is open can be suppressed, so that variations in the flow rate of the slurry among the plurality of slurry outflow passages 82 can be reduced.

  When the dimension of the cavity 83 in the direction orthogonal to the direction in which the slurry passes through the slurry outflow passage 82 is a depth dimension, in the example shown in FIG. 7, the depth dimension is tf + Hn + tr. tf is the distance from the end of the opening of the slurry outflow passage 82 in the cavity 83 to the wall surface 85, and tr is the distance from the end of the opening of the slurry outflow passage 82 in the cavity 83 to the wall surface 86. is there. In the present embodiment, tr and tf are the same size, but they may be different. Hn is the diameter of the slurry outlet passage 82. The depth dimension is preferably 1 mm or more larger than the diameter Hn of the slurry outflow passage 82. In this way, a space for the slurry to flow in the cavity 83 can be secured, and the flow of the slurry in the cavity 83 can be stabilized.

  Thus, the nozzle head 80 has little variation in the flow rate of the slurry flowing out from the plurality of slurry outflow passages 82. For this reason, if a slurry is apply | coated to a sintered compact using the nozzle head 80, the dispersion | variation in the thickness in the surface of a sintered compact will reduce the slurry apply | coated to the surface of a sintered compact. As a result, variations in magnetic properties of the obtained magnet are suppressed. Next, the rotation holding means 32 will be described.

  FIG. 8A is a front view illustrating a schematic configuration of the rotation holding unit according to the present embodiment. FIG. 8-2 is a plan view illustrating a schematic configuration of the rotation holding unit according to the present embodiment. As shown in FIGS. 8A and 8B, the rotation holding unit 32 includes a contact portion 70, a rotation portion 72, and an attachment / detachment portion 74. The rotation holding means 32 has a symmetrical shape about a symmetry plane Pv perpendicular to the rotation axis Zr. The rotation holding means 32 has a structure in which the two contact portions 70 are brought into contact with both end portions 34T and 34T of the sintered body 34 so as to sandwich the sintered body 34 therebetween.

  The two contact portions 70 are members that come into contact with the sintered body 34, and are held by the rotating portion 72 and the detachable portion 74. The two contact portions 70 are disposed to face each other, and the sintered body 34 is disposed between the two contact portions 70. Thus, in the sintered body 34, both end portions 34 </ b> T and 34 </ b> T (in this embodiment, the end portion existing in the longitudinal direction of the sintered body 34) is in contact with the contact portion 70.

  The rotating unit 72 is a drive mechanism that rotates the contact unit 70. The rotating part 72 is provided corresponding to each contact part 70. The rotating part 72 rotates the contact part 70 about an axis parallel to the longitudinal direction of the sintered body 34 (rotating axis Zr in this embodiment) as a rotating axis (R direction in FIGS. 8-1 and 8-2). ). The method by which the rotating unit 72 rotates the contact unit 70 is not particularly limited. For example, a pulley is attached to each of the shaft connecting the contact portion 70 and the rotation shaft of the electric motor, an endless transmission belt is bridged between both pulleys, and the rotation of the electric motor is transmitted to the contact portion 70 via the transmission belt. . Thus, there is a method of rotating the contact portion 70. Further, the rotating shaft of the electric motor may be directly connected to the contact portion 70 to rotate the contact portion 70.

  The attachment / detachment unit 74 includes arms 74a and 74b and an attachment / detachment drive unit 74c that drives the arms 74a and 74b. Each of the arms 74a and 74b supports the contact portion 70 in a rotatable manner. The detachable drive unit 74c moves the arms 74a and 74b in a direction parallel to the rotation axis Zr (in the direction of arrow A in the drawing), thereby moving the contact portion 70 in a direction parallel to the rotation axis Zr (in the direction of arrow A in the drawing). It is a moving mechanism to move. The detachable portion 74 can adjust the distance between the two contact portions 70 by moving the two contact portions 70 in a direction parallel to the rotation axis Zr.

  With such a structure, the distance between the two contact portions 70, that is, the distance between the portions in contact with the sintered body 34 is increased and is made longer than the length in the longitudinal direction of the sintered body 34. 34 can be removed from between the contact portions 70, 70. Moreover, the sintered compact 34 can be hold | maintained by a pair of contact parts 70 and 70 by shortening the distance between the two contact parts 70, and making it the magnitude | size substantially the same as the length of the longitudinal direction of the sintered compact 34. FIG. . Further, the attaching / detaching portion 74 is configured to be able to move the arms 74a and 74b integrally. With such a structure, the attaching / detaching portion 74 can be moved while holding the sintered body 34.

  Thus, the rotation holding means 32 can attach and detach the sintered body 34 by moving the contact portion 70 in the direction parallel to the rotation axis Zr by the attaching and detaching portion 74. The rotation holding means 32 rotates the sintered body 34 around the rotation axis Zr by rotating the contact portion 70 around the rotation axis Zr by the rotation unit 72. Further, since the sintered body 34 can be moved by moving the attaching / detaching portion 74 in the direction of arrow B in FIG. 8B, the sintered body 34 is sandwiched between the attaching / detaching portion 74, and the discharge port 81 and the tray 52. It is possible to move from a position between the two to another position or from another position to a position between the discharge port 81 and the tray 52. Next, the operation of the coating mechanism 14 will be described.

  9A and 9B are explanatory diagrams for explaining the operation of the coating mechanism according to the present embodiment. The application mechanism 14 applies the slurry 35 to the sintered body 34 by the nozzle head 80 included in the application unit 40 of the application means 30 shown in FIG. 2 while rotating the sintered body 34 held by the rotation holding means 32. In this case, the sintered body 34 is disposed on the vertical direction side of the discharge port 81 of the nozzle head 80. Then, as shown in FIG. 9A and FIG. 9B, the sintered body 34 in a position where the slurry 35 discharged from the discharge port 81 of the nozzle head 80 flows out changes its orientation, that is, rotates. While in contact with the slurry 35. The substantially entire surface of the sintered body 34 passes through the position where the slurry 35 reaches, and the slurry 35 discharged from the discharge port 81 is applied.

  Thus, the application mechanism 14 can apply the slurry 35 to the surface of the sintered body 34 by causing the slurry 35 to flow out from the plurality of discharge ports 81 toward the sintered body 34. Moreover, the slurry 35 can be apply | coated to the sintered compact 34 with a simple structure by setting it as the structure which only flows out the slurry 35 like this embodiment. Moreover, since the application mechanism 14 discharges the slurry 35 from the plurality of discharge ports 81, the slurry flow can be prevented from being collected at the center in the width direction of the nozzle head 80 due to surface tension. As a result, the coating mechanism 14 suppresses variations in the thickness of the slurry 35 applied to the sintered body 34. In the present embodiment, the nozzle head 80 can prevent the slurry flow from being offset with respect to the sintered body 34 because the plurality of discharge ports 81 are arranged in a line in the direction of the rotation axis of the rotation holding means 32. . For this reason, the coating mechanism 14 can uniformly apply the slurry 35 to the surface of the sintered body 34.

  In addition, the application mechanism 14 can easily apply the slurry 35 to the surface of the sintered body 34 by causing the discharge port 81 to face in the vertical direction and causing the slurry 35 to flow out by the action of gravity. However, the present embodiment is not limited to such a configuration. For example, the slurry 35 may be discharged from the discharge port 81 in an oblique direction or a horizontal direction, and the slurry 35 may be applied to the sintered body 34. The discharge port 81 of the nozzle head 80 is preferably arranged so that the sintered body 34 exists in the direction in which the slurry 35 is discharged. That is, the discharge port 50 is preferably in a positional relationship facing the sintered body 34.

  The thickness of the slurry 35 applied to the sintered body 34 can be adjusted by adjusting the slurry concentration. That is, the thickness of the slurry 35 applied to the sintered body 34 can be increased by increasing the slurry concentration, and the thickness can be decreased by decreasing the slurry concentration.

  Further, the concentration adjusting unit 44 shown in FIG. 2 preferably maintains the slurry concentration within the range of the reference value ± 0.050 g / cc, and more preferably within the range of ± 0.035 g / cc. By setting the slurry concentration within the above range, it is possible to suppress variations in magnetic characteristics between manufactured magnets. The slurry concentration only needs to be equal to or higher than the concentration that can be applied to the surface of the sintered body 34 with the thickness of the target slurry 35, and the lower limit is not particularly limited. The slurry concentration is 70% by mass or less, preferably 60% by mass or less. By setting the slurry concentration to 70% by mass or less, the slurry 35 can be appropriately moved on the surface of the sintered body 34. For this reason, by rotating the sintered body 34, variations in the thickness of the slurry 35 applied to the sintered body 34 can be suppressed.

  In any of the above embodiments, the coating mechanism 14, the drying mechanism 16, and the transport mechanism 20 are separated from each other. However, the present embodiment is not limited to this, and these may be a single device. That is, the coating mechanism 14 and the drying mechanism 16 may be used as a coating device. In this case, the sintered body 34 may be moved to the processing region of the drying mechanism 16 by moving the rotation holding means 32 of the coating mechanism 14. In addition, the conveyance mechanism 20 for moving the sintered body 34 may be provided separately, or a part of the functions of the conveyance mechanism 20 described above may be added to the coating mechanism 14. Next, a processing procedure for manufacturing a rare earth sintered magnet by applying slurry to a sintered body and heat-treating it with the magnet manufacturing apparatus 10 shown in FIG. 1 will be described.

  FIG. 10 is a flowchart showing a processing procedure when a rare earth sintered magnet is manufactured by the magnet manufacturing apparatus according to the present embodiment. The magnet manufacturing apparatus 10 shown in FIG. 1 transports the sintered body 34 supplied from the sintered body supply mechanism 12 to the coating mechanism 14 by the transport mechanism 20. Thereafter, in step S <b> 11, the magnet manufacturing apparatus 10 holds the sintered body 34 by the rotation holding means 32 of the coating mechanism 14. Specifically, the pair of contact portions 70, 70 of the rotation holding means 32 sandwich both end portions 34 </ b> T in the longitudinal direction of the sintered body 34.

  If the sintered compact 34 is hold | maintained at step S11, a process will be advanced to step S12. In step S <b> 12, the magnet manufacturing apparatus 10 starts rotating the sintered body 34. That is, the rotation holding means 32 included in the coating mechanism 14 of the magnet manufacturing apparatus 10 rotates the contact portion 70 by the rotation portion 72 to rotate the sintered body 34. If rotation of the sintered compact 34 is started by step S12, a process will be advanced to step S13. In step S <b> 13, the magnet manufacturing apparatus 10 applies the slurry 35 to the sintered body 34. Specifically, the rotation holding means 32 of the coating mechanism 14 moves the sintered body 34 between the discharge port 81 of the nozzle head 80 and the tray 52 while rotating the sintered body 34. In addition, the slurry 35 is supplied to the nozzle head 80 by the slurry circulating unit 42. For this reason, the slurry 35 is discharged from the discharge port 81.

  When the slurry 35 is applied to the sintered body 34 in step S13, the process proceeds to step S14. In step S <b> 14, the magnet manufacturing apparatus 10 dries the slurry 35 applied to the sintered body 34. Specifically, the rotation holding means 32 shown in FIG. 1 moves the sintered body 34 to the drying mechanism 16. The drying mechanism 16 dries the sintered body 34 held by the rotation holding unit 32. In the present embodiment, the rotation holding means 32 moves the sintered body 34 while rotating it, and also rotates the sintered body 34 during drying by the drying mechanism 16.

  If the slurry 35 adhering to the sintered compact 34 is dried at step S14, a process will be advanced to step S15. In step S15, the magnet manufacturing apparatus 10 stops the rotation of the sintered body 34. Specifically, the rotation holding means 32 stops the rotation of the rotating unit 72, thereby stopping the rotation of the sintered body 34. Thereafter, the magnet manufacturing apparatus 10 collects the sintered body 34 held by the rotation holding means 32 by the transport mechanism 20 and then moves it to the heat treatment mechanism 18. And a process progresses to step S16 and the heat processing mechanism 18 of the magnet manufacturing apparatus 10 heat-processes the sintered compact 34. FIG. By subjecting the sintered body 34 to heat treatment, the rare earth compound in the slurry adhering to the surface is diffused to the crystal grain boundaries inside the sintered body 34. According to the above procedure, the magnet manufacturing apparatus 10 manufactures a rare earth sintered magnet.

  As described above, the magnet manufacturing apparatus 10 applies the slurry 35 to the sintered body 34 while rotating the sintered body 34, and further continues to rotate the sintered body 34 until the end of drying. The slurry 35 can be uniformly applied to the surface of the film. Further, by performing heat treatment on the sintered body 34 on which the slurry 35 is uniformly applied, variations in surface magnetic flux, residual magnetic flux density, coercive force, and the like can be suppressed. That is, it is possible to suppress a difference in surface magnetic flux, residual magnetic flux density, and coercive force depending on the position of the surface of the rare earth sintered magnet obtained by performing heat treatment on the sintered body 34. Thus, the performance as a magnet can be improved by suppressing variation in surface magnetic flux and the like. As a result, when the rare earth sintered magnet manufactured by the magnet manufacturing apparatus 10 is used as, for example, a permanent magnet of an electric motor, the occurrence of cogging or the like can be suppressed.

  In addition, the magnet manufacturing apparatus 10 can efficiently use the rare earth compound by applying the slurry 35 in which the rare earth compound is dissolved to the sintered body 34 and attaching the rare earth compound to the sintered body 34. That is, the magnet manufacturing apparatus 10 can suppress the rare earth compound from adhering to other than the surface of the sintered body 34. Specifically, in the method of attaching the rare earth compound by vapor deposition, the rare earth compound adheres to a certain region of the vapor deposition apparatus other than the sintered body 34, but the slurry 35 containing the rare earth compound is applied to the sintered body 34. Thus, it is possible to suppress the rare earth compound from adhering to portions other than the sintered body 34. As a result, the rare earth compound can be used efficiently. Further, as in this embodiment, the rare earth compound can be used more efficiently by circulating the slurry, that is, by collecting and reusing the slurry 35 that has not been applied to the sintered body 34.

  Further, in the present embodiment, the slurry 35 can be applied to the entire surface other than the contact portion of the sintered body 34 by causing the contact portion 70 of the rotation holding means 32 to contact only both ends of the sintered body 34. it can. In this way, the portion of the sintered body 34 where the slurry 35 is not applied can be reduced by a mechanism for fixing the sintered body 34 such as the rotation holding means 32. By doing in this way, the rare earth sintered magnet of more uniform performance can be manufactured. In order to obtain such an effect, it is preferable that the two contact portions 70 are brought into contact with both end portions 34T of the sintered body 34 and sandwiched therebetween, but the present embodiment is not limited thereto. The area where the two contact portions 70 are in contact with both end portions 34 </ b> T of the sintered body 34 is the minimum area that can hold the sintered body 34 during the process of rotating the sintered body 34 and applying the slurry 35. However, the present embodiment is not limited to this.

  In the present embodiment, the application of the slurry 35 is started after the rotation holding means 32 starts the rotation of the sintered body 34. For this reason, it can suppress that the slurry 35 accumulates more than necessary on the surface of the sintered compact 34, and can suppress that the slurry 35 scatters. Moreover, since the magnet manufacturing apparatus 10 can finish the application | coating of the slurry 35 appropriately in a short time, while being able to improve working efficiency, productivity is also improved. The coating mechanism 14 may rotate the sintered body 34 coated with the slurry 35 so that the thickness of the slurry 35 adhered to the surface of the sintered body 34 is uniform, and the rotation start timing is as described above. It is not limited.

  After starting the rotation of the sintered body 34, the magnet manufacturing apparatus 10 continuously rotates the sintered body 34 until the drying of the slurry 35 is completed. That is, the sintered body 34 is rotated until the slurry 35 is dried. By doing in this way, it can suppress more reliably that the slurry 35 apply | coated to the sintered compact 34 accumulates in a part of sintered compact 34. FIG. As a result, it is possible to prevent the liquid slurry 35 from accumulating in a part of the sintered body 34 on the vertical direction side and the thickness of the slurry 35 from becoming uneven depending on the position of the sintered body 34. The sintered magnet has more uniform magnetic properties.

  The rotation holding means 32 preferably rotates the sintered body 34 at 5 rpm or more and 50 rpm or less, more preferably 10 rpm or more and 40 rpm or less. By rotating the sintered body 34 at 5 rpm or more, the surplus portion of the slurry 35 applied to the sintered body 34 is quickly moved, and the variation in the thickness of the slurry 35 applied to the sintered body 34 is further increased. It can be reliably reduced. Moreover, since the centrifugal force which acts on the slurry 35 can be made into an appropriate magnitude | size by rotating the sintered compact 34 at 50 rpm or less, the thickness of the slurry 35 apply | coated to the sintered compact 34 is too small. Can be suppressed. The rotation holding means 32 may not continue to rotate the sintered body 34 until the drying of the slurry 35 is completed. For example, the rotation holding means 32 may repeat rotation and stop of the sintered body 34 at regular time intervals. Further, the rotation holding means 32 may stop the rotation of the sintered body 34 during the drying.

  The rotation holding means 32 rotates the sintered body 34 in such a direction that the portion of the sintered body 34 to which the slurry 35 discharged from the discharge port 81 of the nozzle head 80 hits rotates in a direction approaching the discharge port 81. preferable. The rotation holding unit 32 rotates the sintered body 34 in such a direction, so that the coating mechanism 14 can efficiently apply the slurry 35 to the sintered body 34 and the slurry 35 may be scattered. Can be suppressed.

  The magnet manufacturing apparatus 10 can apply the slurry 35 having an appropriate concentration to the sintered body 34 by adjusting the slurry concentration by the concentration adjusting unit 44. Specifically, even if the solvent of the slurry 35 volatilizes or evaporates, the slurry concentration can be kept constant. The rotation holding means 32 preferably rotates the sintered body 34 at 5 rpm or more and 50 rpm or less, more preferably 10 rpm or more and 40 rpm or less. By rotating the sintered body 34 at 5 rpm or more, the surplus portion of the slurry 35 applied to the sintered body 34 is quickly moved, and the variation in the thickness of the slurry 35 applied to the sintered body 34 is further increased. It can be reliably reduced. Moreover, since the centrifugal force which acts on the slurry 35 can be made into an appropriate magnitude | size by rotating the sintered compact 34 at 50 rpm or less, the thickness of the slurry 35 apply | coated to the sintered compact 34 is too small. Can be suppressed.

(Evaluation)
The slurry 35 was applied to the sintered body 34 by the nozzle head 80 of the present embodiment to manufacture a rare earth sintered magnet. The thickness of the slurry 35 before the sintered body 34 coated with the slurry 35 was heat-treated was measured. Further, the flow rate of the slurry 35 flowing out from each discharge port 81 of the nozzle head 80 was measured.

<Manufacture of sintered body>
A sintered body (sintered magnet) was produced by the following method. First, as a raw material alloy, a main phase alloy mainly forming a main phase of a magnet and a grain boundary alloy mainly forming a grain boundary were cast by the SC method. The composition of the main phase alloy is 23.0 mass% Nd-2.6 mass% Dy-5.9 mass% Pr-0.5 mass% Co-0.18 mass% Al-1.1 mass% B- bal. Fe. The composition of the grain boundary system alloy was 30.0 mass% Dy-0.18 mass% Al-0.6 mass% Cu-bal. Fe.

Next, these raw material alloys were coarsely pulverized by hydrogen pulverization, respectively, and then jet milled by high-pressure N ₂ gas to obtain fine powders each having an average particle diameter D = 4 μm. The obtained fine powder of the main phase alloy and the fine powder of the grain boundary alloy were mixed at a ratio of main phase alloy: grain boundary alloy = 9: 1 to obtain a raw material powder of the rare earth sintered magnet. A magnetic powder was prepared. Next, using this magnetic powder, molding was performed in a magnetic field under conditions of a molding pressure of 1.2 ton / cm ² and an orientation magnetic field of 15 kOe to obtain a molded body. Then, the sintered compact of the rare earth sintered magnet which has said composition was manufactured by baking the obtained molded object on the conditions of 1060 degreeC and 4 hours. The obtained sintered body was immersed in a 3% by mass nitric acid / ethanol mixed solution for 3 minutes and then immersed in ethanol for 1 minute twice to perform surface treatment of the sintered body. In addition, these treatments were performed while applying ultrasonic waves. The dimension of the obtained sintered body was 2 mm × 45 mm × 30 mm.

<Manufacture of slurry>
The slurry attached to the sintered body was produced as follows. First, 5 parts by mass of butyral resin (Sekisui Chemical BM-S) was dissolved in 550 parts by mass of isopropyl alcohol to prepare a resin solution. Next, 445 parts by mass of this resin solution and DyH ₂ (average particle diameter D = 5 μm) were placed in a ball mill, and dispersed for 10 hours using 3 mm zirconia balls in an Ar atmosphere to produce a slurry. The Dy hydride used was prepared by occluding Dy powder at 350 ° C. for 1 hour in a hydrogen atmosphere, followed by treatment at 600 ° C. for 1 hour in an Ar atmosphere. The hydride thus obtained was subjected to X-ray diffraction measurement, and was identified as DyH ₂ by analogy from ErH _{2 of} ASTM card 47-978.

<Applying and drying slurry>
The slurry produced as described above was put into the slurry tank 54 of the coating mechanism 14 shown in FIG. 2 and circulated at a flow rate of 500 cc / min. In order to prevent concentration fluctuation due to solvent volatilization during circulation, the concentration adjusting unit 44 adjusted the slurry concentration to be in the range of 1.258 to 1.263 (g / cc). Specifically, the pump 66 was driven according to the measurement result of the slurry concentration, and the solvent was charged from the solvent tank 64 to the slurry tank 54.

Next, in a state where the sintered body was held by the rotation holding means 32, the sintered body was rotated at a rotation speed of 20 rpm by the rotating unit 72. For this rotating sintered body, slurry is applied (slurry is discharged) for 5 seconds from the discharge port of the nozzle head according to the example of the present embodiment and the comparative example, and then the sintered body is rotated. The slurry was dried while leveling the slurry applied to the sintered body. In this embodiment, the target slurry thickness (film thickness) is 20 μm. In addition, by setting 20μm thickness, the surface of the sintered body, it is possible to deposit DyH ₂ at a rate of 5.0 mg / cm ^2.

  Then, the rare earth sintered magnet was manufactured by performing the heat processing hold | maintained at 800 degreeC for 1 hour with respect to the sintered body after drying, and also giving the aging treatment hold | maintained at 540 degreeC for 1 hour. In addition, the size of the obtained rare earth sintered magnet was 2 mm (thickness: magnetic anisotropy direction) × 45 mm × 30 mm.

  FIG. 11 is an explanatory diagram showing the arrangement of the ejection ports 81 included in the nozzle head used for the evaluation. 12 and 13 are schematic views showing the internal structure of a nozzle head according to a comparative example. The nozzle head 80 according to the present embodiment evaluated five types of nozzle heads 80 in total by changing the radiuses ra and rb of the curved surface or the outer plane length Ls shown in FIG. As a comparative example, four types of nozzle heads were evaluated. As shown in FIG. 11, the five types of examples and the four types of comparative examples all have thirteen discharge ports 81. As shown in FIG. 11, each of the discharge ports 81 is assigned an identification number of N1 to N13 in order from the discharge port 81 (left side in the figure) existing on the outermost side in one width direction. In the five types of embodiments, in each of the nozzle heads 80, the radius ra of the curved surface 87Ra and the radius rb of the curved surface 87Rb shown in FIG. 6 are equal (ra = rb).

  A nozzle head 80a shown in FIG. In the nozzle head 80 a, the slurry outflow passage 82 and the slurry introduction passage 88 a are orthogonal to each other, and the slurry introduction passage 88 a that opens into the cavity 83 is a straight line, so that the slurry is introduced into the cavity 83 without being bent. The structure of other parts is the same as that of the nozzle head 80 of the first embodiment. A nozzle head 80b shown in FIG. In the nozzle head 80b, a plurality of slurry outflow passages 82 are opened in a cavity 83b in which wall surfaces 87b on both sides in the width direction are formed by a single curved surface having a radius rc. The structure of other parts is the same as that of the nozzle head 80 of the first embodiment. Next, configurations of Examples 1 to 7 and Comparative Examples 1 and 2 will be briefly described.

(1) In Example 1, in the nozzle head 80 shown in FIG. 6, ra = rb = 1.5 mm, Ls = 2 mm, H = 10 mm, and h = 7 mm.
(2) In Example 2, in the nozzle head 80 shown in FIG. 6, ra = rb = 1.0 mm, Ls = 2 mm, H = 10 mm, and h = 8 mm.
(3) In Example 3, in the nozzle head 80 shown in FIG. 6, ra = rb = 3.0 mm, Ls = 2 mm, H = 10 mm, and h = 4 mm.
(4) In Example 4, in the nozzle head 80 shown in FIG. 6, ra = rb = 1.5 mm, Ls = 1 mm, H = 10 mm, and h = 7 mm.
(5) In Example 5, in the nozzle head 80 shown in FIG. 6, ra = rb = 1.5 mm, Ls = 4 mm, H = 10 mm, and h = 7 mm.
(6) In Example 6, in the nozzle head 80 shown in FIG. 6, ra = rb = 0.5 mm, Ls = 2 mm, H = 10 mm, and h = 9 mm.
(7) In Example 7, in the nozzle head 80 shown in FIG. 6, ra = rb = 1.5 mm, Ls = 0.5 mm, H = 10 mm, and h = 7 mm.
(8) In Comparative Example 1, in the nozzle head 80a shown in FIG. 12, ra = rb = 1.5 mm, Ls = 2 mm, H = 10 mm, and h = 7 mm.
(9) In Comparative Example 2, in the nozzle head 80b shown in FIG. 13, ra = rb = 5.0 mm, Ls = 2 mm, H = 10 mm, and h = 0 mm.

In each of Examples 1 to 7, Comparative Example 1, and Comparative Example 2, the flow rate (cm ³ / min) of the slurry was measured for each of the discharge ports N1 to N13, and the uniform discharge performance in the width direction of the slurry was evaluated. did. The flow rate of the slurry for each discharge port N1 to N13 is to prepare a soft container so that sampling can be performed from a specific discharge port, sample the slurry from each discharge port, measure the mass, and determine the flow rate from the slurry density at this time. Calculated. The results are shown in Table 1. The results are shown in Table 1.

  FIG. 14 is a plan view showing a position where the thickness of the slurry is measured. For Example 1, Comparative Example 1, and Comparative Example 2, the thickness (μm) of the slurry formed on the surface of the sintered body 34 after drying the slurry is measured at 5 measurement points P1 to P5 shown in FIG. Measured at points. The thickness of the slurry was measured using a micrometer. Specifically, the thickness of the sintered body 34 after drying the slurry is measured with a micrometer together with the thickness of the slurry, and the thickness (2 mm) of the sintered body 34 is subtracted from the obtained value. Was divided by 2 to determine the thickness of the slurry. The results are shown in Table 2. From the evaluation results in Tables 1 and 2, the correlation between the flow rate of the slurry for each of the discharge ports N1 to N13 and the thickness of the slurry formed on the surface of the sintered body 34 was confirmed.

  From the evaluation results in Table 1, in each of Examples 1 to 5, the difference in the flow rate of the slurry between the central portion (P3) and both sides in the width direction (P1, P5) is more than that of Comparative Examples 1 to 4. I understand that it is small. In addition, in Examples 1 to 5, it can be seen that the standard deviation σ is smaller than those in Comparative Examples 1 to 4. As described above, Example 1 to Example 5 have less variation in the slurry flow rate in the width direction than Comparative Examples 1 to 4.

  From the evaluation results in Table 1, it can be seen that in Example 1, the difference in the flow rate of the slurry between the central portion and both sides in the width direction is smaller than those of Comparative Example 1 and Comparative Example 2. Further, it can be seen that Example 1 has a smaller standard deviation σ than Comparative Examples 1 and 2. Thus, Example 1 has less variation in the flow rate of the slurry on the surface of the sintered body 34 than Comparative Example 1 and Comparative Example 2. Therefore, the rare earth sintered magnet obtained by heat-treating the sintered body 34 of Example 1 is more than the rare earth sintered magnet obtained by heat-treating the sintered body 34 of Comparative Example 1 and Comparative Example 2. Therefore, it can be predicted that the variation in magnetic characteristics in a single magnet will be small.

  In Example 1, the slurry is introduced into the cavity 83 after being bent, but in Comparative Example 1, the slurry is introduced into the cavity 83 without being bent. The standard deviation σ of Example 1 is slightly less than 1/10 that of Comparative Example 2. As described above, when the slurry is introduced, the variation in the flow rate of the slurry in the width direction is greatly reduced by passing through the bent portion.

  In Example 1, the wall surfaces on both sides in the width direction of the cavity 83 are formed by two curved surfaces and one plane, but in Comparative Example 2, the wall surfaces on both sides in the width direction of the cavity 83 are formed by one curved surface. Has been. The standard deviation σ of Example 1 is a little less than 1/6 of Comparative Example 2, and by making the shape of the wall surfaces on both sides in the width direction of the cavity 83 as in this embodiment, the variation in the flow rate of the slurry in the width direction can be reduced. It is greatly reduced.

  In Example 4, the outer plane length Ls is 1 mm. The standard deviation σ of Example 4 is slightly more than half that of Comparative Example 2. Further, in Example 4, the outer plane length Ls is 1 mm, while in Example 5, the outer plane length Ls is 4 mm. The standard deviation σ of Example 5 is slightly less than 1/3 of Example 4. In Example 7, the outer plane length Ls is 0.5 mm. The standard deviation σ of Example 7 is smaller than those of Comparative Example 1 and Comparative Example 2. Thus, the variation in the slurry flow rate in the width direction is reduced as the outer plane length Ls increases. If the outer plane length Ls is 0.5 mm or more, it is effective in reducing variation in the slurry flow rate in the width direction.

  In the order of Example 3, Example 1, and Example 2, the radii ra and rb of the curved surfaces 87Ra and 87Rb of the cavity 83 become smaller. The standard deviation σ decreases in the order of Example 3, Example 1, and Example 2. From these results, in the range where the radii ra and rb of the curved surfaces 87Ra and 87Rb are 1.0 mm or more and 3.0 mm or less, the variation in the slurry flow rate in the width direction is reduced as the radii ra and rb of the curved surfaces 87Ra and 87Rb are reduced. Is done.

  Comparing Example 2 and Example 6, in Example 2, the radii ra and rb of the curved surfaces 87Ra and 87Rb are larger. The standard deviation σ decreases in the order of the sixth embodiment and the second embodiment. From these results, in the ranges where the radii ra and rb of the curved surfaces 87Ra and 87Rb are 0.5 mm or more and 1.0 mm or less, the larger the radii ra and rb of the curved surfaces 87Ra and 87Rb, the larger the variation in the slurry flow rate in the width direction. Reduced. That is, if the radii ra and rb of the curved surfaces 87Ra and 87Rb are at least 0.5 mm or more, the variation in the flow rate of the slurry in the width direction is reduced.

  From Example 3 and Example 6, when the radii ra and rb of the curved surfaces 87Ra and 87Rb are 0.5 mm or more and 3.0 mm or less, it is effective in reducing variation in the slurry flow rate in the width direction. If the ratio h / H between the planar length h and the cavity height H is 2/5 or more and 9/10 or less, the variation in the flow rate of the slurry in the width direction is sufficiently reduced.

DESCRIPTION OF SYMBOLS 10 Magnet manufacturing apparatus 12 Sintered body supply mechanism 14 Application | coating mechanism 16 Drying mechanism 18 Heat processing mechanism 20 Conveyance mechanism 22 Control apparatus 30 Application | coating means 32 Rotation holding means 34 Sintered body 35 Slurry 40 Application | coating part 42 Slurry circulation part 44 Concentration adjustment part 70 Contact portion 72 Rotating portion 74 Detachable portion 80, 80a, 80b Nozzle head 80B Matching portion 80PB Lower surface 80F First member 80R Second member 81 Discharge port 82, 82c, 82o Slurry outflow passage 83, 83b Cavity 84S Outer plane 84, 85, 86, 87, 87b Wall surface 87Ra, 87Rb Curved surface 87S Flat surface 88H Slurry introduction port 88, 88a Slurry introduction passage 89 Slurry supply passage

Claims (6)

A plurality of slurry outflow passages arranged at predetermined intervals to allow the slurry containing the rare earth compound to pass therethrough and to flow out;
Together store the slurry into a cavity surrounded by a plurality of walls, the wall surface in which a plurality of the slurry outlet passage is open to said cavity, located at both ends of the direction in which the slurry outlet passage of several are arranged, respectively A slurry holding part having a shape in which two curved surfaces are connected by a single plane;
A slurry introduction passage that opens into the slurry holding portion and introduces the slurry into the slurry holding portion from a direction intersecting with a direction in which the slurry passes through the slurry outflow passage;
A slurry supply passage that intersects with the slurry introduction passage and is connected to the slurry introduction passage to allow the slurry to flow into the slurry introduction passage;
Only including,
In the direction in which the slurry passes through the slurry outflow passage, the one plane is located between the two curved surfaces,
The two curved surfaces are concave surfaces;
The slurry introduction passage opens one at a central portion in the direction in which the plurality of slurry outflow passages are arranged.
A slurry supply apparatus characterized by the above. The slurry supply apparatus according to claim 1, wherein an angle formed between the slurry introduction passage and the slurry supply passage is within 90 ° ± 10 °. 3. The slurry supply apparatus according to claim 1, wherein a dimension of the plane is 2/5 or more and 9/10 or less of a dimension of the cavity in a direction in which the slurry passes through the slurry outflow passage. 2. The cavity is provided with an outer flat surface connected to one of the two curved surfaces on the outer side of each of the slurry outflow passages arranged on the outermost side in a direction in which the plurality of slurry outflow passages are arranged. 4. The slurry supply apparatus according to any one of items 1 to 3 . Each of said outer plane, according to claim 4 the distance from the outermost slurry outlet passage in the direction in which the plurality of the slurry outlet passage is arranged to one of the two curved surfaces is 1mm or more 10mm or less Slurry supply device. Holding means for holding in contact with the sintered body ;
Rotating means for rotating the sintered body;
A slurry supply apparatus according to any one of claims 1 to 5 ,
The coating apparatus, wherein the slurry is caused to flow out from the slurry outflow passage of the slurry supply device toward the sintered body while rotating the sintered body by the rotating means.

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