JP2018145512A - Powdery filling device, sintered magnet manufacturing installation and sintered magnet manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a powdery filling device which can fill powder with uniformity and high density to a container for filling.SOLUTION: A powdery filling device 1 comprises: a powder housing chamber 10 having an opening 111 with a grid member 15 and a connection 112 to connect the opening 111 and a container for filling 20 in airtight in the bottom edge; multiple gas feed pipes 123 connected to the upper part of the powder housing chamber 10; a valve main body 131 provided so that multiple gas duct in main body 1311 connected to the multiple gas feed pipes 123 respectively go through inside independently each other; a cylindrical shaft intrusion hole 1312 arranged to cross with all of the multiple gas duct in main body 1311 in the valve main body 131, and a columnar shaft 132 fitted to the shaft intrusion hole 1312 rotatably; gas duct in shaft 1321 provided corresponding to the multiple gas duct in main body 1311 in the shaft 132; and multiple resource side gas feed pipe 14 connecting the multiple gas duct in main body 1311 to gas resource respectively.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a powder filling device for filling powder into a container (hereinafter referred to as a “filler container”), a sintered magnet manufacturing apparatus using the powder filling device, and a sintered magnet manufacturing method.

  When producing a sintered magnet, conventionally, a compression molding method has been used in which sintering is performed after producing a compact by performing compression molding while orienting the raw material powder in a magnetic field. A PLP (press-less process) method has been developed in which a raw material powder is filled in a container to be filled at a predetermined density and then oriented and sintered in a magnetic field without performing compression molding (Patent Document 1). The PLP method makes it easy to orient the particles of the raw material powder by not performing compression molding, and it is possible to reduce the size of the apparatus by not performing compression molding, thereby easily making an oxygen-free atmosphere. Therefore, since the particle size can be reduced without oxidizing the raw material powder, there is an advantage that the coercive force can be increased. The PLP method also has an advantage that a sintered magnet having a shape close to that of the final product can be obtained. Here, the density at which the raw material powder is filled in the container to be filled is higher than the density in which the raw material powder is simply put into the container to be filled (natural filling) (and lower than the density of the compact in the compression molding method). Is required. Hereinafter, filling a container to be filled with such a density is referred to as “high density filling”.

  Patent Document 2 discloses a powder filling apparatus for filling a filling target container with powder at high density. In this powder filling apparatus, the cylindrical guide member is detachably and hermetically attached to the filling target container so that the cylindrical guide member communicates with the filling target container at the lower opening thereof. The lower opening of the cylindrical guide member is provided with a grid member formed of a plurality of wire meshes stretched at regular intervals, a plate member with a large number of holes, or the like. Further, a lid is attached to the upper opening of the cylindrical guide member so as to be hermetically sealed. A gas supply pipe that supplies gas from the compressed gas source to the inside of the cylindrical guide member and a gas discharge pipe that discharges gas from the inside of the cylindrical guide member are connected to the lid. The gas supply pipe is provided with an electromagnetic valve.

  In this powder filling apparatus, powder is put into a cylindrical guide member from an upper opening, and a lid is attached to the upper opening, whereby a powder storage chamber having a lower surface (lower opening) as a grid member is formed. Then, the container to be filled is attached to the lower opening, and the pressure in the powder storage chamber is alternately raised and lowered by repeatedly opening and closing the electromagnetic valve provided in the gas supply pipe, and the powder to be filled through the grid member. High density filling.

JP 2006-019521 A JP 2001-072001

  In the powder filling apparatus described in Patent Document 2, one gas supply pipe is connected to the powder storage chamber. However, if there is only one gas supply pipe, it is difficult to make the pressure of the gas in the cylindrical guide member uniform, and hence it is difficult to make the filling density of the powder into the filling target container uniform. When the packing density of the powder becomes non-uniform, the powder becomes difficult to be oriented in the magnetic field at the portion where the packing density is high, and the magnetic characteristics are deteriorated. Further, in the portion where the packing density is low, the shrinkage rate becomes large after sintering, and a dent or a cavity is generated. In addition, when there is only one gas supply pipe, the gas pressure in the cylindrical guide member cannot be increased, and predetermined high-density filling may not be performed.

  For these reasons, it is desirable that a plurality of gas supply pipes are connected to the powder storage chamber. However, if the plurality of gas supply pipes are respectively provided with solenoid valves, it is difficult to completely match the timings of opening and closing the plurality of solenoid valves. If the timing of opening / closing the plurality of solenoid valves is shifted, the pressure becomes non-uniform in the powder storage chamber depending on the positional relationship between the plurality of gas supply pipes. Moreover, the maximum pressure of the gas in the entire powder storage chamber is also lowered. Therefore, the powder cannot be filled uniformly and at a high density.

  The problem to be solved by the present invention is to produce a powder filling apparatus capable of filling a container to be filled with powder uniformly and at a high density, and a sintered magnet having high magnetic properties and free from dents and cavities. It is possible to provide a sintered magnet manufacturing apparatus and a sintered magnet manufacturing method using the powder filling apparatus.

The powder filling apparatus according to the present invention, which has been made to solve the above problems,
a) A powder storage chamber having an opening provided with a grid member at the lower end, and a connection portion for airtight connection with a container to be filled in the opening;
b) a plurality of gas supply pipes connected to the upper part of the powder storage chamber;
c) a valve body provided so that a plurality of gas passages in the body respectively connected to the plurality of gas supply pipes penetrate through the interior independently of each other;
d) a cylindrical shaft insertion hole provided inside the valve main body so as to intersect all of the plurality of gas flow paths in the main body, and a columnar shaft rotatably inserted in the shaft insertion hole; ,
e) A gas flow path in the shaft provided on the shaft corresponding to each of the gas flow paths in the plurality of main bodies, and
f) A plurality of supply side gas supply pipes respectively connecting the plurality of gas flow paths in the main body to a gas supply source.

  In the powder filling apparatus according to the present invention, the powder is supplied into the powder storage chamber, and the container to be filled is connected to the connection portion in an airtight manner. In addition, while rotating the shaft, gas is supplied from each of the plurality of supply-source-side gas supply pipes to the gas flow passage in the main body connected thereto. Thereby, at the timing when the gas flow path in the main body and the gas flow path in the shaft communicate with each other by the rotation of the shaft, the gas flows from the gas flow path in the main body to the gas flow path in the shaft, and the gas flow path in the shaft and the powder storage chamber. The powder is supplied into the powder storage chamber through a gas supply pipe connected to the upper part (above the opening). Thus, pressure is repeatedly applied to the powder in the powder storage chamber, and the powder is filled into the filling target container through the grid member. Since the in-body gas flow channel and the in-shaft gas flow channel communicate each time the shaft rotates halfway, the gas is repeatedly supplied to the powder storage chamber at a cycle that is 1/2 of the rotation cycle of the shaft.

  According to the powder filling apparatus according to the present invention, the gas is supplied from any gas supply pipe to the powder storage chamber at the same time when the shaft rotates to a predetermined rotational position. Therefore, the pressure in the powder storage chamber can be made nearly uniform, whereby the filling target container can be uniformly filled with the powder. In addition, the time at which the pressure of the gas supplied from each gas supply pipe becomes maximum can be matched, and the average value of the pressure in the entire powder storage chamber can be increased. Can be filled.

  The cross sections of the gas flow path in the body and the gas flow path in the shaft are not limited to a specific shape, but are desirably rectangular (including a square) having two sides parallel to the shaft axis. As a result, when the shaft is rotated, the gas flow path in the main body and the gas flow path in the shaft start and end at the same time in the entire axial direction of the shaft, so that it is possible to apply a pressure close to a pulse shape. . In particular, by making the cross-sectional shapes of the gas flow path in the main body and the gas flow path in the shaft into a rectangle having two sides parallel to the shaft axis as long sides, the gas supply time per time can be shortened, and Since the supply amount of gas per unit time can be increased, it is possible to apply a pressure closer to a pulse shape. Alternatively, the cross section of the gas flow path in the main body and the gas flow path in the shaft may be circular in that the constriction hole at the time of manufacture is easy.

  In the powder filling apparatus according to the present invention, the powder storage chamber includes a lid and a powder storage chamber main body, and a sealing gas (gas supplied to the internal space of the powder storage chamber) is formed at the boundary between the lid and the powder storage chamber main body. A sealing material that expands when supplied with the gas, a sealing gas supply path that supplies the sealing gas to the sealing material, and a pressing mechanism that presses the lid and the powder container body together. Is desirable. According to this configuration, the sealing material is expanded by supplying the sealing gas to the sealing material through the supply path, and the lid and the powder storage chamber body are pressed against each other by the pressing mechanism, so that The airtightness of the container can be increased, and the packing density of the powder into the container to be filled can be increased.

The sintered magnet manufacturing apparatus according to the present invention includes:
A powder filling device according to the present invention;
Applying a magnetic field to the powder without applying mechanical pressure while the powder that is the raw material of the sintered magnet filled in the container to be filled by the powder filling device is filled in the container to be filled An orientation part for orienting the powder,
A sintered part that is sintered by heating the powder without applying a mechanical pressure in a state where the powder is filled in the container to be filled;
Is provided.

The method for producing a sintered magnet according to the present invention comprises:
A powder filling step of filling a container to be filled with powder as a raw material of a sintered magnet using the powder filling apparatus according to the present invention;
An orientation step of orienting the powder by applying a magnetic field to the powder without applying mechanical pressure while the powder is still filled in the container to be filled;
A sintering step is performed in which the powder is sintered by heating without applying mechanical pressure while the powder is filled in the container to be filled.

  According to the present invention, it is possible to fill a container to be filled with powder at a nearly uniform and high density, and thereby it is possible to manufacture a sintered magnet having high magnetic properties and free from dents and cavities.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic (a) which shows the whole structure of one Embodiment of the powder filling apparatus which concerns on this invention, and the top view (b) which shows arrangement | positioning of an air supply port and an exhaust port. The bottom view of the main body in the powder filling apparatus of this embodiment. Sectional drawing which shows the planar shape of the gas flow path in a shaft in the powder filling apparatus of this embodiment. The top view (a) and longitudinal cross-sectional view (b) which show an example of the filling object container filled with powder using the powder filling apparatus of this embodiment. Schematic which shows the operation | movement which fills powder using the powder filling apparatus of this embodiment. The figure which shows a mode that a shaft rotates in a cross section perpendicular | vertical to the axis | shaft of this shaft. The figure which shows a mode that the powder which protruded from the upper end of the cavity is scraped off with a scraper. Schematic which shows the example which provided the film | membrane etc. inside the lid | cover which is a modification of a powder filling apparatus. Schematic explaining the example of the densification process after filling the powder into a filling object container. The graph which shows the result of having measured the time change of the flow volume of the compressed gas which passes a gas supply pipe | tube about the powder filling apparatus of this embodiment (modification) (a) and a comparative example (b). The graph which shows the result of having measured the time change of the pressure in a powder storage room about the powder filling apparatus of a modification. The graph which shows the result of having calculated | required the variation of the average value of the filling density to the filling object container by the difference of the pressure of compressed gas, and the powder feeding weight for every cavity about the powder filling apparatus of a modification. Results of experimentally determining the average value of the actual packing density and the variation in the powder feeding weight for each cavity when the target value of the packing density to the filling target container is 3.3 g / cm ³ for the powder filling device of the modified example Graph showing. Results of experimentally determining the average value of the actual packing density and the variation in the powder feeding weight for each cavity when the target value of the packing density to the filling target container is 3.5 g / cm ³ for the powder filling device of the modified example Graph showing. The graph which shows the result of having measured the time change of the pressure in a powder storage chamber about two examples from which the cross-sectional shape of the gas flow path in a main body and the gas flow path in a shaft differs. The graph which shows the result of having measured the filling density to the filling object container about two examples from which the cross-sectional shape of the gas flow path in a main body and the gas flow path in a shaft differs. Schematic which shows the whole structure of the sintered magnet manufacturing apparatus which concerns on a present Example.

  Embodiments of a powder filling apparatus, a sintered magnet manufacturing apparatus, and a sintered magnet manufacturing method according to the present invention will be described with reference to FIGS.

(1) Configuration of Powder Filling Device 1 of the Present Embodiment FIG. 1 (a) is a schematic diagram showing the overall configuration of the powder filling device 1 of the present embodiment. The powder filling apparatus 1 includes a powder storage chamber 10, and the powder storage chamber 10 includes a main body 11 and a lid 12.

  The main body 11 has a rectangular parallelepiped box shape, the entire ceiling portion is open, and an opening 111 is provided at the bottom (lower end). In the present embodiment, sixteen openings 111 are provided in total at six equal intervals in the long side direction of the rectangle at the bottom of the main body 11 and three at equal intervals in the short side direction at intervals different from the long side direction. ing. The opening 111 is rectangular, and is arranged such that the long side of the opening 111 and the short side of the bottom of the main body 11 are parallel to each other. In this embodiment, the shape of the opening 111 is determined so as to match the shape of the cavity of the container 20 to be filled, which will be described later, which is a mold used when producing a sintered magnet by the PLP method. The shape of the opening 111 is not limited to this example, and may be appropriately determined according to the shape of the container to be filled.

A grid member 15 is attached to each opening 111 (FIG. 2). The grid member 15 is formed by stretching a plurality of wires at regular intervals in the vertical and horizontal directions. In this embodiment, RFeB (R ₂ Fe ₁₄ B: R is a rare earth element such as Nd) based magnetic alloy powder having an average particle diameter of 3 μm is used as a filling target in the filling target container 20, and the wire of the grid member 15 is used. The interval was 3 mm. Thus, although the wire interval of the grid member 15 is three orders of magnitude larger than the average particle size of the powder, the powder is simply placed on the grid member 15 by aggregation of the powder particles of the RFeB-based magnet alloy. By itself, the powder will not fall between the wires.

  The lid 12 is a rectangular parallelepiped box having the same cross section as that of the main body 11, and is attached to the ceiling portion of the main body 11. The lid 12 is entirely open at the bottom, and an air supply port 121 and an exhaust port 122 are provided on the ceiling. FIG. 1B shows the arrangement of the air supply ports 121 and the exhaust ports 122 in the lid 12, and the opening 111 positioned below the lid 12 when the lid 12 is attached to the main body 11 is indicated by a broken line. . A total of 18 exhaust ports 122 are provided, one above each opening 111. There are three air supply ports 121 in the long side direction of the rectangle of the ceiling portion at intervals twice as large as the exhaust ports 122 and the openings 111, and two in the short side direction at the same intervals as the exhaust ports 122 and the openings 111. There are six. Each air supply port 121 is arranged at the center of gravity of a minimum rectangle formed with four exhaust ports 122 as apexes.

  One gas supply pipe 123 is connected to each lid 12 from the outside of the powder storage chamber 10 to each air supply port 121.

  The gas supply pipe 123 is connected to the valve device 13. The valve device 13 includes a valve main body 131 and a shaft 132. The valve body 131 is provided with six in-body gas flow paths 1311 that are the same number as the gas supply pipes 123 so as to penetrate through the inside independently. In the present embodiment, the six main body gas flow paths 1311 are parallel to each other and arranged at equal intervals. One gas supply pipe 123 is connected to one end of each in-body gas flow path 1311, and one supply source side gas supply pipe 14 is connected to the other end. A gas having a pressure higher than atmospheric pressure (hereinafter referred to as “high pressure gas”) is supplied to the supply source side gas supply pipe 14 from a gas cylinder (not shown) as a gas supply source. In this embodiment, the high-pressure gas is an argon gas that does not react with the RFeB magnet alloy powder. Instead of argon gas, other rare gas or nitrogen gas may be used.

  A cylindrical shaft insertion hole 1312 is provided inside the valve main body 131 so as to intersect with all of the six in-body gas flow paths 1311. In this embodiment, the six shaft insertion holes 1312 are arranged in parallel to each other and at the same interval as the six in-body gas flow paths 1311. The shaft insertion holes 1312 are provided so as to be orthogonal to the six in-body gas flow paths 1311. The shaft 132 is inserted into the shaft insertion hole 1312, and the in-shaft gas flow path 1321 is provided corresponding to each of the six main body gas flow paths 1311. With these configurations, the shaft 132 rotates around an axis in the same direction as the direction in which the shaft insertion hole 1312 extends, and the in-shaft gas flow path 1321 is orthogonal to the axis. The shaft 132 is connected to a motor (not shown) that is a drive source for rotating the shaft 132 around its axis.

  In this embodiment, the cross-sectional shape of the in-shaft gas flow path 1321 is a rectangle having two sides parallel to the axis of the shaft 132 as shown in FIG. The shape and size of the cross section of the in-body gas flow channel 1311 are the same as those of the in-shaft gas flow channel 1321. On the other hand, the cross sections of the gas supply pipe 123 and the supply source side gas supply pipe 14 are both rectangular at the connection portion with the gas flow path 1311 in the main body, as in the cross section of the gas flow path 1311 in the main body. Within a certain length range, the shape gradually changes as the distance from the connection portion increases, and is circular outside the range.

  The diameter of the shaft 132 is 16 mm in this embodiment. The interval between the gas flow paths 1321 in the shaft was 24 mm. In this embodiment, the cross-sectional sizes of the in-body gas flow path 1311 and the in-shaft gas flow path 1321 are 6.5 mm for the long side and 3.8 mm for the short side. These are merely examples, and the present invention is not limited to these examples. The length of the long side of the cross section of the gas flow path 1311 in the body and the gas flow path 1321 in the shaft is for attaching the gas supply pipe 123 and the supply source side gas supply pipe 14 between the adjacent gas flow paths 1311 in the main body. Within the range in which a hole-free portion can be provided, the longer one is desirable because the amount of high-pressure gas that can be supplied to the powder storage chamber 10 at a time can be increased. On the other hand, the length of the short side of the cross section of the gas flow path 1311 within the main body and the gas flow path 1321 within the shaft is such that the gas flow path 1311 within the main body and the gas flow path 1321 within the shaft are rotated while the shaft 132 is rotated around the axis. It is desirable to determine the diameter of the shaft 132 so that the communication time is about 5 to 20% of the whole.

  At the lower end of the wall of the main body 11, a connecting portion made of a lower seal material 112 for airtight connection with the filling target container 20 is provided. On the other hand, an upper seal material 113 for airtight connection with the lid 12 is provided at the upper end of the wall of the main body 11. Both the lower sealing material 112 and the upper sealing material 113 are balloon-shaped things that expand when supplied with high-pressure gas. A sealing gas supply path 114 that supplies high-pressure gas to the lower sealing material 112 and the upper sealing material 113 is provided in the wall of the main body 11, and the sealing gas supply path 114 is a seal that supplies sealing gas. Connected to a gas supply source (not shown). This sealing gas supply source is provided separately from the gas supply source that supplies the high-pressure gas to the supply-side gas supply pipe 14, and the supplied high-pressure gas is air. Further, a pressing cylinder (pressing mechanism) 124 that presses the lid 12 downward is connected to the upper surface of the lid 12. While the lid 12 is pressed downward by the holding cylinder 124, a sealing gas is supplied to the lower sealing material 112 and the upper sealing material 113 to expand them, so that the space between the main body 11 and the filling target container 20 and the lid 12 are increased. The airtightness between the main bodies 11 is maintained.

(2) Structure of filling target container 20 The filling target container 20 has a flat cavity 22 having the same planar shape as the opening 111 of the main body 11 of the powder filling apparatus 1 on the upper surface side of the rectangular flat main body 21. A total of 18 pieces are provided at the same interval as the opening 111, 6 pieces in the long side direction and 3 pieces in the short side direction (FIGS. 1A and 4). When filling the filling target container 20 with the powder by the powder filling device 1, the filling target container 20 and the main body 11 are used in the state in which the positions of the cavity 22 and the opening 111 are aligned in order from the bottom.

(3) Operation | movement of the powder filling apparatus 1 of this embodiment Operation | movement of the powder filling apparatus 1 of this embodiment is demonstrated using FIGS. First, the powder P is supplied into the main body 11 with the main body 11 and the lid 12 being separated (FIG. 5A). At this time, the powder P is placed on the grid member 15 provided in the opening 111, but does not fall between the wires of the grid member 15 for the reason described above.

  Next, the filling target container 20 is arranged directly below the main body 11 so that the opening 111 of the main body 11 and the position of the cavity 22 of the filling target container 20 are aligned. At the same time, the lid 12 is placed on the main body 11. Then, high-pressure gas is supplied from the sealing gas supply source to the lower sealing material 112 and the upper sealing material 113 through the sealing gas supply path 114, and the lid 12 is pushed downward by the pressing cylinder 124 (FIG. 5B). Thereby, the airtightness between the main body 11 and the filling target container 20 and between the lid 12 and the main body 11 is ensured by the lower sealing material 112 and the upper sealing material 113, respectively.

  In this state, high-pressure gas is supplied from the gas cylinder, which is a gas supply source, to each supply source-side gas supply pipe 14, and the shaft 132 is rotated around the axis at a constant speed by a motor, which is a drive source.

  FIG. 6 shows a state in which the shaft 132 rotates in a cross section perpendicular to the axis of the shaft 132. The main body gas flow path 1311 shown in the figure is connected to the supply source side gas supply pipe 14 in the upper part of the figure, and is connected to the gas supply pipe 123 in the lower part of the figure. In the drawing, an arrow indicated by a thick line indicates the rotation direction of the shaft 132, and an arrow indicated by a thin line indicates the flow of high-pressure gas. As shown in FIG. 6 (a), when the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft are not in communication, the gas flow was supplied from the gas cylinder to the gas flow path 1311 in the main body through the supply source side gas supply pipe 14. The high-pressure gas is blocked by the shaft 132 and is not supplied to the gas supply pipe 123 and the powder storage chamber 10 ahead. Thereafter, when the shaft 132 rotates, a part of the in-shaft gas flow path 1321 communicates with the main body gas flow path 1311 (FIG. 6B), and the high pressure gas is supplied from the supply source side gas supply pipe 14. It passes through the in-shaft gas flow path 1321 and is supplied to the powder containing chamber 10 through the remaining part of the main body gas flow path 1311 and the gas supply pipe 123. The supply amount of the high-pressure gas per unit time increases as the rotation angle advances after the in-body gas flow path 1311 and the in-shaft gas flow path 1321 begin to communicate, and the in-body gas flow path 1311 and the in-shaft gas flow It becomes maximum when the angle of the path 1321 coincides (FIG. 6C), and then decreases. When the rotation angle further advances, the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft do not communicate with each other (FIG. 6 (d)), and the high pressure gas is not supplied to the gas supply pipe 123 and the powder storage chamber 10. The operation up to this point is repeated every time the shaft 132 makes a half rotation, and the high-pressure gas is repeatedly supplied to the powder storage chamber 10 at a cycle that is half the rotation cycle of the shaft 132. FIG. 6 shows only one set of the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft, but the six gas flow paths in the main body 1311 and the gas flow path 1321 in the shaft are arranged in parallel, In addition, since the in-shaft gas flow path 1321 is orthogonal to the axis around which the shaft 132 rotates, all the in-shaft gas flow paths 1321 start and end communication with the in-body gas flow path 1311 at the same timing.

  The high-pressure gas supplied to the powder storage chamber 10 in this way is discharged from the exhaust port 122 with a slight delay from the supply timing due to the exhaust resistance of the exhaust port 122. Thereby, in the powder storage chamber 10, a pressure repeats a raise and fall with the said period. The powder P is repeatedly pushed downward (air tapping) at the same period by this pressure, pushed downward from between the wires of the grid member 15, and falls into the cavity 22 of the container 20 to be filled (FIG. 5 (c). )). Note that the pressure of the high-pressure gas may be appropriately determined by a person skilled in the art through preliminary experiments for each powder to be handled. Moreover, the ratio (duty ratio) of supplying compressed gas in one cycle is the length of the short side of the cross section of the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft in the powder filling apparatus 1 of the present embodiment. In other words, the length is determined by the length in the rotational direction, and this length may be designed after obtaining an appropriate duty ratio by conducting a preliminary experiment with a conventional powder filling apparatus using a solenoid valve, for example.

  By performing this operation for a predetermined time, the vicinity of the upper end of the cavity 22 is filled with the powder P. Thereafter, the pressing by the holding cylinder 124 is released, and the filling target container 20 is separated from the main body 11 (FIG. 5 (d)). Thus, the operation of filling the cavity 22 with the powder P is completed.

  Actually, when the container 20 to be filled is arranged immediately below the main body 11, there is a slight gap between the upper end of the cavity 22 of the container 20 to be filled and the grid member 15 of the main body 11. It is supplied to the cavity 22 so as to slightly protrude from the upper end of the cavity 22. Therefore, as shown in FIG. 7, the powder P slightly protruding from the upper end of the cavity 22 is scraped off by the scraper 36, and the upper end of the powder P is leveled so as to be flush with the upper surface of the filling target container 20. The scraper 36 has first to third scraping portions 361 to 363, and the height of the tip in contact with the powder P decreases from the first scraping portion 361 toward the third scraping portion 363. By moving the entire scraper 36 so as to come into contact with the powder P in the order of the first scraper 361, the second scraper 362, and the third scraper 363, the powder P can be gradually scraped. .

  According to the powder filling device 1 of the present embodiment, since all the in-shaft gas passages 1321 start and end communication with the in-body gas passage 1311 at the same timing while the shaft 132 is rotating, In the storage chamber 10, the supply of compressed air from all the air supply ports 121 starts and ends at the same timing. Therefore, the pressure of the gas in the powder storage chamber 10 at each time can be made nearly uniform, whereby the filling target container 20 can be filled with the powder P uniformly. Moreover, the time when the pressure of the compressed gas supplied from each air supply port 121 becomes maximum can be matched. Therefore, the average value of the pressure in the entire powder storage chamber 10 can be increased, whereby the filling target container 20 can be filled with the powder P at a high density.

(4) Modified Example of Powder Filling Device of the Present Embodiment FIG. 8 shows a modified example of the powder filling device of the present embodiment. A powder filling apparatus 1A according to this modification includes a silicone rubber film 126 stretched in a lateral direction inside a lid 12A of a powder storage chamber 10A, and a metal net provided directly below the film 126. A film suppression member 127 is provided. Other configurations are the same as those of the powder filling apparatus 1 described above.

  The method of using the powder filling apparatus 1A is the same as that of the powder filling apparatus 1. When the compressed gas is introduced into the powder storage chamber 10A from the air supply port 121, the compressed gas itself does not pass through the membrane 126, but pushes the membrane 126 downward (a dashed line in FIG. 8), so that it is below the membrane 126. The gas pushes the powder P, and the powder P can be pushed downward from between the wires of the grid member 15 and supplied to the cavity 22 of the container 20 to be filled, as in the powder filling device 1. By using the membrane 126, when the compressed gas is introduced into the powder storage chamber 10A from the air supply port 121, the powder P in the main body 11 is above the membrane 126, that is, the air supply port 121 and the exhaust port 122 side. It is possible to prevent the air supply port 121 and the exhaust port 122 from being clogged by being scattered in the region.

  If the film suppression member 127 is not provided, the film 126 may move down too much and come into contact with the powder P in the main body 11. When the membrane 126 comes into contact with the powder P, a compressive force acts directly on the powder P, and a density distribution is generated. Therefore, the film | membrane 126 is prevented from contacting the powder P by providing the film | membrane suppression member 127 under the film | membrane 126 in the lid | cover 12A.

  The material of the film 126 is not limited to silicone rubber as long as it has flexibility. For example, polyurethane or the like can be used. The film suppressing member 127 is not limited to a net as long as it prevents the film 126 from descending below the film suppressing member 127 and allows gas to pass therethrough. It may be a hole or a bar arranged side by side.

  FIG. 8 shows a state in which the spacer 30 is arranged between the main body 11 and the filling target container 20 instead of arranging the filling target container 20 directly below the main body 11. The spacer 30 may be used not only in the powder filling apparatus 1A of the modified example but also in the powder filling apparatus 1 described above. The spacer 30 is formed by providing 18 through holes 31 in the plate material in the same shape and in the same arrangement as the opening 111, and a sealing material 32 provided on the lower surface so as to surround the entire 18 through holes 31. is there. When filling the container 20 with the powder, the container 20, the spacer 30, and the main body 11 are stacked in order from the bottom with the positions of the cavity 22, the through hole 31, and the opening 111 aligned. When the high pressure gas is supplied from the sealing gas supply source to the lower sealing material 112 and the upper sealing material 113 and the lid 12 is pushed downward by the holding cylinder 124, the lid 12 and the main body 11, the main body 11 and the spacer 30, and the spacer 30 Airtightness between the filling target containers 20 is ensured by the upper seal material 113, the lower seal material 112, and the seal material 32, respectively.

  By using the spacer 30 as described above, the powder P can be filled into the cavity 22 at a higher density as described below. When the powder P is filled into the cavity 22 by the powder filling device 1 or 1A using the spacer 30, the powder P is filled into the through hole 31 aligned with the cavity 22 together with the cavity 22 of the filling target container 20. . Thereafter, the powder P protruding from the upper end of the through hole 31 is removed by the scraper 36 (FIG. 9A), and a punch 35 having the same shape as the through hole 31 of the spacer 30 is inserted into the through hole 31 from above. Thereby, the powder P in the through-hole 31 is pushed into the cavity 22 of the container 20 to be filled (FIG. 9B). As a result, the cavity 22 is filled with the powder P at a higher density than when filled with the powder filling device 1 or 1A.

(5) Experimental results First, in the powder filling apparatus 1A of the modified example, one flow meter is provided in each gas supply pipe 123, and the flow rate of the compressed gas flowing through each gas supply pipe 123 during the operation of the powder filling apparatus 1A. An experiment was conducted to measure the time change. In this experiment, nitrogen having a pressure of 0.4 MPa was used as the compressed gas. The cycle of supplying the compressed gas was 80 msec. In addition, as a comparative example, instead of the valve device 13 in the powder filling device 1A of the present embodiment, one electromagnetic valve is provided for each gas supply pipe 123, and the gas on the powder storage chamber 10A side than the electromagnetic valve. Compressed gas that flows through each gas supply pipe 123 by opening and closing the solenoid valve at an interval of 50 msec using nitrogen at a pressure of 0.4 MPa for an apparatus provided with a flow meter in the supply pipe 123 (open state is 20 sec, closed state is 30 msec) An experiment was conducted to measure the time change of the flow rate. In this embodiment, the flow rate per unit time of the compressed gas passing through one gas supply pipe 123 when the valve device 13 is fully opened is about 80 L / min, whereas the electromagnetic valve of the comparative example Since it becomes resistance when compressed gas passes, the flow rate per unit time of compressed gas passing through one gas supply pipe 123 in the fully open state is about 50 L / min, which is smaller than that of the present embodiment. . Therefore, in the comparative example, in order to compensate for the decrease in the flow rate per unit time, the compressed gas supply cycle is set to 50 msec, which is shorter than that of the present embodiment as described above.

  The results of this experiment are shown in FIG. 10 (a) for the powder filling apparatus 1A of the present embodiment, and in FIG. 10 (b) for the powder filling apparatus using the electromagnetic valve of the comparative example. (a) shows measurement results with five gas supply pipes 123, and (b) shows measurement results with six gas supply pipes. According to this measurement result, in the present embodiment, the data of the five gas supply pipes 123 are almost completely overlapped, and the compressed gas having substantially the same flow rate changes from the five gas supply pipes 123 with substantially the same time change. It turns out that it is supplied to 10 A of powder storage chambers. Moreover, the value of the flow rate when the flow rate reaches a peak is almost the same in any peak. On the other hand, in the comparative example, the value of the flow rate when the flow rate reaches a peak is different for each gas supply pipe 123, and the value of the flow rate is also different for each peak in the same gas supply pipe 123. In the comparative example, the time at which the flow rate reaches a peak (specified in FIG. 10 by the time from the start of the flow rate measurement) is slightly different for each gas supply pipe 123. The data of these comparative examples is considered to be caused by the difficulty in opening and closing at the same opening and timing in each solenoid valve. On the other hand, in the powder filling apparatus 1A of the present embodiment, the gas passages 1311 in the main body of the valve device 13 are opened at the same opening degree and at the same timing, so the same problem as the electromagnetic valve does not occur.

  FIG. 11 shows the results of measuring the pressure in the powder storage chamber 10A by periodically supplying compressed gas into the powder storage chamber 10A under the same conditions as above for the powder filling apparatus 1A of the present embodiment. The pressure in the powder storage chamber 10A was measured on the upper side (gas supply pipe 123 side) and the lower side (opening 111 side) of the membrane 126, respectively. It can be seen that the pressure increases and decreases in accordance with the cycle of the compressed gas supply by the valve device 13 both above and below the membrane 126.

In FIG. 12, in the powder filling apparatus 1A of the present embodiment, a device in which the number of the air supply ports 121 is increased to 14 (the number of the exhaust ports 122 is the same as the above example) is used. Experiments were conducted to fill the container 20 to be filled with an RFeB magnet alloy powder having an average particle diameter of about 3 μm under each condition, and the average value of powder density in 18 cavities of the container 20 to be filled and the feeding The result of the experiment which calculates | requires the variation in weight is shown. From this experimental result, as the pressure of the compressed gas is increased, the packing density of the powder is also increased, and when the pressure of the compressed gas is 0.4 MPa or more, the variation in the powder weight per cavity is 0.3 g (of the packing density). It can be seen that the variation can be suppressed to less than 0.145 g / cm ³ ).

Therefore, experiments were conducted 5 times each for the target values of packing density of 3.3 g / cm ³ (compressed gas pressure 0.53 MPa) and 3.5 g / cm ³ (0.63 MPa). The average value and the variation in the weight of the feed were obtained. The results are shown in FIG. 13 when the target value is 3.3 g / cm ^{3 and} in FIG. 14 when the target value is 3.5 g / cm ³ . In any case, the average value was obtained with good reproducibility in 5 experiments and with almost no deviation from the target packing density, and the variation in the powder feed weight for each cavity was suppressed to less than 0.3 g.

Next, the results of experiments performed on two examples in which the cross-sectional shapes of the in-body gas flow channel 1311 and the in-shaft gas flow channel 1321 are different are shown. Here, the cross-sectional shape of the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft is a rectangular shape in which the long side parallel to the axis of the shaft 132 is 5.5 mm and the short side perpendicular to the long side is 4.5 mm. Example A and Example B, whose long side is 6.5 mm longer than Example A and whose short side is 3.8 mm shorter than Example A, were the subjects of the experiment. Example A and Example B, the cross-sectional area of the main body in the gas flow path 1311 and the shaft the gas flow path 1321, 24.8 mm ² Example A, is 24.7 mm ² Example B. The compressed gas pressure (0.4 MPa) and the valve opening / closing cycle (80 msec) were the same in Example A and Example B. The number of the air supply ports 121 is 10 and the number of the exhaust ports 122 is the same as the above example. FIG. 15 shows the results of measuring the time change of the pressure in the powder storage chamber 10A below the membrane 126 for these examples A and B for a time of 100 msec, which is slightly longer than one cycle. It can be seen that in Example B, the pressure rises faster in Example B than in Example A, and the time during which pressure is applied is shorter. This result shows that the application of pressure and the release are effective in Example B having a long side.

  FIG. 16 shows the results of measuring the packing density of the powder into the container 20 to be filled in these cases A and B in a plurality of cases where the valve opening and closing periods are different. In the case where the valve opening / closing cycle is the longest (100 msec), the packing density of Example A and Example B was almost the same. The packing density was higher. This is thought to be due to the application of pressure and the opening of the release in Example B.

(6) One Embodiment of Sintered Magnet Manufacturing Apparatus and Sintered Magnet Manufacturing Method Next, an embodiment of a sintered magnet manufacturing apparatus and a sintered magnet manufacturing method according to the present invention will be described with reference to FIG. The sintered magnet manufacturing apparatus 40 of the present embodiment includes a powder filling apparatus 1 (or 1A; hereinafter, only the symbol “1” is shown), a powder densification apparatus 42, a lid mounting portion 43, and an orientation apparatus. (Orientation part) 44 and sintering furnace (sintering part) 45. Moreover, the sintered magnet manufacturing apparatus 40 includes a conveying device (belt conveyor) 46 that conveys the filling target container 20 in the order of the powder filling device 1, the scraper 36, the lid attaching portion 43, the orientation device 44, and the sintering furnace 45. Among these devices, each device other than the sintering furnace 45 is housed in a common outer container 47 having an inert gas atmosphere inside, and an inert gas is separately supplied into the sintering furnace 45 as well. In an inert gas atmosphere. With the components that make the inside of the outer container 47 and the sintering furnace 45 an inert gas atmosphere, the whole from the powder filling apparatus 1 to the sintering furnace 45 can be made an oxygen-free atmosphere. In the powder filling apparatus 1, a part of the supply source side gas supply pipe 14 and a gas supply source (not shown) are arranged outside the outer container 47. Since the valve device 13 is disposed in the outer container 47, the distance between the valve device 13 and the air supply port 121 can be shortened, and the application of pressure to the powder storage chamber 10 and the opening of the opening are improved.

  The powder filling apparatus 1 is an apparatus for filling a container 20 to be filled with powder that is a raw material of a sintered magnet, and has the configuration as described above. The configuration of the scraper 36 is also as described above. The lid attaching portion 43 is an apparatus for attaching a lid of the filling target container 20 (different from the lid 12 of the powder filling apparatus 1) to the filling target container 20 filled with powder. This lid is used to prevent the alloy powder from scattering from the filling target container 20 due to a magnetic field in the orientation device 44, gas convection in the sintering furnace 45, or the like.

  The orientation device 44 includes a coil 441 and a container lifting device 442. The coil 441 has a substantially vertical (vertical) axis and is disposed above the container lifting device 442. The container lifting device 442 is a device that lifts and lowers the filling target container 20 that has been transported by the container transporting device 46 between the container 441 and the inside of the coil 441.

  The sintering furnace 45 includes a sintering chamber 451 that accommodates a large number of containers 20 to be filled, a carry-in port 452 that communicates with the outer vessel 47, and a door 453 having heat insulation provided at the carry-in port 452.

  One embodiment of the operation of the sintered magnet manufacturing apparatus 40 and the sintered magnet manufacturing method according to the present invention will be described. First, the container transport device 46 transports the filling target container 20 to the powder filling device 1, and fills the cavity 22 of the filling target container 20 with the alloy powder as described above. Next, the excess powder on the top is removed by the scraper 36. Subsequently, the container transport device 46 transports the filling target container 20 to the lid attaching portion 43 and attaches the lid to the filling target container 20. Thereafter, the filling target container 20 is transported to the aligning device 44 by the container transporting device 46, placed in the coil 441 by the container lifting / lowering device 442 in the aligning device 44, and the powder in the filling target container 20 is generated by the magnetic field generated by the coil 441. Are oriented. After this orientation treatment, the container 20 to be filled is lowered from the inside of the coil 441 by the container lifting device 442, transported to the sintering furnace 45 by the container transport device 46, and a predetermined temperature (usually 800) in the sintering chamber 451. The powder in the filling target container 20 is sintered by heating to ˜1100 ° C. As described above, according to the sintered magnet manufacturing apparatus 40 and the sintered magnet manufacturing method of the present embodiment, a sintered magnet is manufactured by the PLP method in which orientation and sintering are performed in a magnetic field without performing compression molding. The

  So far, the embodiments of the powder filling apparatus, the sintered magnet manufacturing apparatus, and the sintered magnet manufacturing method according to the present invention have been described. Needless to say, the present invention is not limited to each of the above-described embodiments. Various modifications are possible within the scope of the gist.

DESCRIPTION OF SYMBOLS 1, 1A ... Powder filling apparatus 10, 10A ... Powder storage chamber 11 ... Main body 111 of powder storage chamber ... Opening 112 ... Lower sealing material (connection part)
113 ... Upper sealing material 114 ... Sealing gas supply path 12, 12A ... Powder storage chamber lid 121 ... Air supply port 122 ... Exhaust port 123 ... Gas supply pipe 124 ... Cylinder 126 ... Membrane 127 ... Membrane suppression member 13 ... Valve device 131 ... Valve main body 1311 ... In-body gas flow path 1312 ... Shaft insertion hole 132 ... Shaft 1321 ... In-shaft gas flow path 14 ... Source-side gas supply pipe 15 ... Grid member 20 ... Filling target container 21 ... Main body of filling target container 22 ... Cavity 30 ... Spacer 31 ... Spacer through-hole 32 ... Sealing material 35 ... Punch 36 ... Scraper 361, 362, 363 ... Scraper 40 ... Sintered magnet manufacturing device 43 ... Lid mounting portion 44 ... Orientation device 441 ... Coil 442 ... Container lifting device 45 ... Sintering furnace 451 ... Sintering chamber 452 ... Carry-in entrance 453 ... Sintering chamber door 46 ... Container transfer device 47 ... External

Claims (6)

a) A powder storage chamber having an opening provided with a grid member at the lower end, and a connection portion for airtight connection with a container to be filled in the opening;
b) a plurality of gas supply pipes connected to the upper part of the powder storage chamber;
c) a valve body provided so that a plurality of gas passages in the body respectively connected to the plurality of gas supply pipes penetrate through the interior independently of each other;
d) a cylindrical shaft insertion hole provided inside the valve main body so as to intersect all of the plurality of gas flow paths in the main body, and a columnar shaft rotatably inserted in the shaft insertion hole; ,
e) A gas flow path in the shaft provided on the shaft corresponding to each of the gas flow paths in the plurality of main bodies, and
f) A powder filling apparatus comprising: a plurality of supply side gas supply pipes each connecting the plurality of gas passages in the main body to a gas supply source.   2. The powder filling apparatus according to claim 1, wherein cross-sectional shapes of the gas flow path in the main body and the gas flow path in the shaft are rectangles having two sides parallel to the axis of the shaft.   The powder filling apparatus according to claim 2, wherein the two sides are long sides of the rectangle.   The powder storage chamber includes a lid and a powder storage chamber main body, and a sealing material that expands when a sealing gas is supplied to a boundary between the lid and the powder storage chamber main body, and supplies the sealing gas to the sealing material The powder filling apparatus according to any one of claims 1 to 3, further comprising a gas supply path for sealing, and a pressing mechanism that presses the lid and the powder storage chamber body together. The powder filling device according to any one of claims 1 to 4,
A magnetic field is applied to the powder without applying mechanical pressure while the powder as a raw material of the sintered magnet filled in the container to be filled by the powder filling apparatus is filled in the container to be filled. An orientation part for orienting the powder by applying,
A sintered part that is sintered by heating the powder without applying a mechanical pressure in a state where the powder is filled in the container to be filled;
A sintered magnet manufacturing apparatus comprising: A powder filling step of filling a container to be filled with powder that is a raw material of a sintered magnet using the powder filling device according to any one of claims 1 to 4,
An orientation step of orienting the powder by applying a magnetic field to the powder without applying mechanical pressure while the powder is still filled in the container to be filled;
A sintered magnet manufacturing method comprising: performing a sintering process by heating the powder without applying mechanical pressure while the powder is filled in the container to be filled. .

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