JP6848544B2 - Powder filling equipment, sintered magnet manufacturing equipment and sintered magnet manufacturing method - Google Patents

Description

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

In the production of sintered magnets, a compression molding method has been conventionally used in which raw material powder is oriented in a magnetic field and compression molding is performed to prepare a molded product, and then sintering is performed. A PLP (press-less process) method has been developed in which 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). In the PLP method, the particles of the raw material powder are easily oriented by not performing compression molding, and the device can be miniaturized by not performing compression molding, whereby an oxygen-free atmosphere can be easily created. 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. In addition, the PLP method has an advantage that a sintered magnet having a shape close to that of the final product can be obtained. Here, the density of filling the raw material powder into the container to be filled is higher than the density of simply putting the raw material powder into the container to be filled (natural filling) (and lower than the density of the molded product in the compression molding method). Is required. Hereinafter, filling the container to be filled with the powder at such a density is referred to as "high density filling".

Patent Document 2 discloses a powder filling device for filling a container to be filled with powder at a high density. In this powder filling device, the tubular guide member is detachably and hermetically attached to the filling target container so that the tubular guide member communicates with the filling target container at its lower opening. The lower opening of the tubular guide member is provided with a grid member formed of a wire mesh stretched at regular intervals, a plate material having a large number of holes bored, or the like. In addition, a lid is hermetically attached to the upper opening of the tubular guide member. A gas supply pipe that supplies gas from the compressed gas source to the inside of the tubular guide member and a gas discharge pipe that discharges gas from the inside of the tubular guide member are connected to the lid. A solenoid valve is provided in the gas supply pipe.

In this powder filling device, a powder storage chamber having a lower surface (lower opening) as a grid member is formed by pouring powder into the tubular guide member from the upper opening and then attaching a lid to the upper opening. Then, a container to be filled is attached to the lower opening, and the pressure in the powder storage chamber is alternately increased and decreased by repeatedly opening and closing the solenoid valve provided in the gas supply pipe, and the powder is passed through the grid member to the container to be filled. Fill with high density.

Japanese Unexamined Patent Publication No. 2006-019521 Japanese Unexamined Patent Publication No. 2001-072001

In the powder filling device 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 tubular guide member uniform, and therefore it is difficult to make the filling density of the powder in the container to be filled uniform. When the packing density of the powder becomes non-uniform, it becomes difficult for the powder to be oriented in a magnetic field in a portion where the packing density is high, and the magnetic characteristics deteriorate. Further, in the portion where the packing density is low, the shrinkage rate becomes large after sintering, and dents and cavities occur. Further, if there is only one gas supply pipe, the pressure of the gas in the tubular guide member cannot be increased, and a predetermined high-density filling may not be possible.

For these reasons, it is desirable that a plurality of gas supply pipes are connected to the powder storage chamber. However, if solenoid valves are provided in each of the plurality of gas supply pipes, it is difficult to completely match the opening and closing timings of the plurality of solenoid valves. If the opening / closing timings of the plurality of solenoid valves are deviated, the pressure becomes non-uniform in the powder storage chamber depending on the positional relationship of the plurality of gas supply pipes. In addition, the maximum pressure of the gas in the entire powder storage chamber is also lowered. Therefore, it is not possible to fill the powder uniformly and at high density.

The problem to be solved by the present invention is to manufacture a powder filling device capable of uniformly and densely filling a container to be filled with powder, and a sintered magnet having high magnetic characteristics and no dents or cavities. It is an object of the present invention to provide a sintered magnet manufacturing apparatus and a sintered magnet manufacturing method using the powder filling apparatus.

The powder filling device according to the present invention made to solve the above problems is
a) At the lower end, an opening provided with a grid member, and a powder storage chamber having a connection portion for airtightly connecting to the container to be filled at the opening.
b) With a plurality of gas supply pipes connected to the upper part of the powder storage chamber,
c) With a valve body provided so that a plurality of gas flow paths in the main body connected to the plurality of gas supply pipes penetrate the inside independently of each other.
d) A cylindrical shaft fitting hole provided so as to intersect all of the plurality of gas flow paths in the main body and a cylindrical shaft rotatably fitted into the shaft fitting hole inside the valve body. ,
e) A gas flow path in the shaft provided on the shaft corresponding to each of the plurality of gas flow paths in the main body, and a gas flow path in the shaft.
f) It is characterized by including a plurality of source-side gas supply pipes for connecting the plurality of gas flow paths in the main body to the gas supply source.

In the powder filling device according to the present invention, the powder is supplied into the powder storage chamber, and then the container to be filled is airtightly connected to the connection portion. Then, while rotating the shaft, gas is supplied from each of the plurality of source-side gas supply pipes to the gas flow path in the main body connected to the pipes. As a result, at the timing when the gas flow path in the main body and the gas flow path in the shaft communicate with each other due to 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. It is supplied into the powder storage chamber through a gas supply pipe connected to the upper part (above the opening). In this way, pressure is repeatedly applied to the powder in the powder storage chamber, and the powder is filled in the filling target container through the grid member. Since the gas flow path in the main body and the gas flow path in the shaft communicate with each other every half rotation of the shaft, the gas is repeatedly supplied to the powder storage chamber at a cycle of 1/2 of the rotation cycle of the shaft.

According to the powder filling device according to the present invention, gas is supplied from any gas supply pipe to the powder storage chamber at the same time when the shaft rotates to a predetermined rotation position. Therefore, the pressure in the powder storage chamber can be made close to uniform, so that the container to be filled can be uniformly filled with the powder. In addition, the time when 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, so that the powder can be filled in the container to be filled with high density. Can be filled.

The cross section of the gas flow path in the main body and the gas flow path in the shaft is not limited to a specific shape, but is preferably a rectangle (including a square) having two sides parallel to the axis of the shaft. As a result, as the shaft is rotated, the gas flow path in the main body and the gas flow path in the shaft start and end communication in the entire axial direction of the shaft at the same time, so that a pressure close to a pulse can be applied. .. In particular, by making the cross-sectional shape of the gas flow path in the main body and the gas flow path in the shaft a rectangle having two long sides parallel to the axis of the shaft, the gas supply time per time is shortened and the gas supply time is shortened. Since the amount of gas supplied per unit time can be increased, it becomes possible to apply a pressure closer to a pulse. 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 constriction during manufacturing is easy.

In the powder filling device according to the present invention, the powder storage chamber includes a lid and a powder storage chamber main body, and a sealing gas (a gas supplied to the internal space of the powder storage chamber) is provided at the boundary between the lid and the powder storage chamber main body. A sealing material that expands when supplied (different from), 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 storage chamber body against each other. 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 main body are pressed against each other by the pressing mechanism, thereby between the lid and the powder storage chamber main body. It is possible to increase the airtightness of the powder and increase the filling density of the powder in the container to be filled.

The sintered magnet manufacturing apparatus according to the present invention is
The powder filling device according to the present invention and
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 device is still filled in the container to be filled. An orientation portion that orients the powder by allowing the powder to be oriented,
A sintered portion that sinters the powder by heating the powder without applying mechanical pressure while the powder is still filled in the container to be filled.
To be equipped.

The method for manufacturing a sintered magnet according to the present invention is
A powder filling step of filling a container to be filled with powder as a raw material for a sintered magnet using the powder filling device 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.
It is characterized in that a sintering step is performed in which the powder is sintered by heating the powder without applying mechanical pressure while the powder is still filled in the container to be filled.

INDUSTRIAL APPLICABILITY According to the present invention, powder can be filled in a container to be filled with powder at a density close to uniform and high density, whereby a sintered magnet having high magnetic properties and no dents or cavities can be manufactured.

A schematic view (a) showing the overall configuration of an embodiment of the powder filling device according to the present invention, and a top view (b) showing the arrangement of an air supply port and an exhaust port. The bottom view of the main body in the powder filling apparatus of this embodiment. The cross-sectional view which shows the planar shape of the gas flow path in a shaft in the powder filling apparatus of this embodiment. Top view (a) and vertical cross-sectional view (b) showing an example of a container to be filled using the powder filling device of the present embodiment. The schematic diagram which shows the operation of filling powder using the powder filling device of this embodiment. The figure which shows the state which a shaft rotates by the cross section perpendicular to the axis of the shaft. The figure which shows the state of scraping the powder protruding from the upper end of a cavity with a scraper. The schematic diagram which shows the example which provided the membrane or the like inside the lid which is the modification of the powder filling apparatus. The schematic diagram explaining the example of the densification treatment after filling a container with a filling with powder. The graph which shows the result of having measured the time change of the flow rate of the compressed gas passing through a gas supply pipe for the powder filling apparatus of this Embodiment (modification example) (a) and comparative example (b). The graph which shows the result of having measured the time change of the pressure in the powder accommodating chamber for the powder filling apparatus of a modification. The graph which shows the result of having obtained the average value of the filling density in the container to be filled, and the variation of the powder feed weight for each cavity by an experiment for the powder filling apparatus of a modified example, due to the difference in the pressure of the compressed gas. For the powder filling device of the modified example, the result of experimentally finding the average value of the actual filling density and the variation of the powder feed weight for each cavity when the target value of the filling density to the container to be filled is 3.3 g / cm ^3. Graph showing. For the powder filling device of the modified example, the result of experimentally finding the average value of the actual filling density and the variation of the powder feed weight for each cavity when the target value of the filling density to the container to be filled is 3.5 g / cm ^3. Graph showing. The graph which shows the result of having measured the time change of the pressure in a powder accommodating chamber for two examples which the cross-sectional shape of a gas flow path in a body and a gas flow path in a shaft is different. The graph which shows the result of having measured the filling density in the container to be filled about two examples which the cross-sectional shape of a gas flow path in a main body and a gas flow path in a shaft is different. The schematic diagram which shows the whole structure of the sintered magnet manufacturing apparatus which concerns on this Example.

An embodiment of a powder filling device, a sintered magnet manufacturing device, and a sintered magnet manufacturing method according to the present invention will be described with reference to FIGS. 1 to 17.

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

The main body 11 has a rectangular parallelepiped box shape, and the entire ceiling portion is open, and an opening 111 is provided at the bottom portion (lower end). In the present embodiment, six openings 111 are provided at equal intervals in the long side direction of the rectangle at the bottom of the main body 11, and three openings 111 are provided at equal intervals in the short side direction at intervals different from the long side direction, for a total of 18 openings. ing. The opening 111 is rectangular, and is arranged so 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 the present embodiment, the shape of the opening 111 is determined to match the shape of the cavity of the container 20 to be filled, which is a mold used when manufacturing 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 vertically and horizontally at regular intervals. In the present embodiment, RFeB (R ₂ Fe ₁₄ B: R is a rare earth element such as Nd) magnet alloy powder having an average particle size of 3 μm is filled into the filling container 20 to be filled with the wire of the grid member 15. The interval was 3 mm. As described above, the distance between the wires of the grid member 15 is three orders of magnitude larger than the average particle size of the powder, but the powder is simply placed on the grid member 15 due to the aggregation of the powder particles of the RFeB-based magnet alloy. By itself, the powder does not pass between the wires and fall.

The lid 12 is a rectangular parallelepiped box-shaped lid having the same cross section as the main body 11, and is attached to the ceiling of the main body 11. The entire bottom of the lid 12 is open, and the ceiling is provided with an air supply port 121 and an exhaust port 122. FIG. 1B shows the arrangement of the air supply port 121 and the exhaust port 122 in the lid 12, and the opening 111 located below the lid 12 when the lid 12 is attached to the main body 11 is shown by a broken line. .. A total of 18 exhaust ports 122 are provided, one directly above each opening 111. The number of air supply ports 121 is three in the long side direction of the rectangle of the ceiling at twice the interval of the exhaust port 122 and the opening 111, and two in the short side direction at the same interval as the exhaust port 122 and the opening 111, in total. Six are provided. Each air supply port 121 is arranged at the smallest rectangular center of gravity formed with the four exhaust ports 122 as vertices.

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

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

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

In the present embodiment, the shape of the cross section of the gas flow path 1321 in the shaft 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 gas flow path 1311 in the main body are the same as those of the gas flow path 1321 in the shaft. On the other hand, the cross sections of the gas supply pipe 123 and the gas supply pipe 14 on the supply source side 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 outside the range, the shape is circular.

The diameter of the shaft 132 is 16 mm in this embodiment. The distance between the gas flow paths 1321 in the shaft was set to 24 mm. The size of the cross section of the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft was 6.5 mm on the long side and 3.8 mm on the short side in this embodiment. It should be noted that these are examples, and the present invention is not limited to this example. The length of the long side of the cross section of the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft is for attaching the gas supply pipe 123 and the gas supply pipe 14 on the supply source side between the adjacent gas flow paths 1311 in the main body. It is desirable that the longer one can increase the amount of high-pressure gas that can be supplied to the powder storage chamber 10 at one time within the range in which the portion without holes can be provided. On the other hand, 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 is such that the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft are set while rotating the shaft 132 around the shaft. It is desirable to consider the diameter of the shaft 132 so that the communication time is about 5 to 20% of the total.

At the lower end of the wall of the main body 11, a connecting portion made of a lower sealing material 112 for airtightly connecting to the filling container 20 is provided. On the other hand, an upper sealing material 113 for airtightly connecting to 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 have a balloon shape that expands when a high-pressure gas is supplied. A sealing gas supply path 114 for supplying 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 for supplying the sealing gas. It is connected to a gas supply source (not shown). The sealing gas supply source is provided separately from the gas supply source that supplies the high-pressure gas to the supply source-side gas supply pipe 14, and the high-pressure gas supplied 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 pressing the lid 12 downward with the pressing cylinder 124, the sealing gas is supplied to the lower sealing material 112 and the upper sealing material 113 to expand them, thereby causing the lid 12 to be between the main body 11 and the filling container 20 and the lid 12. The airtightness between the main bodies 11 is maintained.

(2) Configuration of Filling Target Container 20 The filling target container 20 has a flat plate-shaped cavity 22 having the same planar shape as the opening 111 of the main body 11 of the powder filling device 1 on the upper surface side of the rectangular flat plate-shaped main body 21. Six in the long side direction and three in the short side direction are provided at the same interval as the opening 111, for a total of 18 pieces (FIGS. 1 (a) and 4). When the powder filling device 1 fills the filling target container 20 with the powder, the filling target container 20 and the main body 11 are used in a state of being overlapped with the cavities 22 and the openings 111 aligned in order from the bottom.

(3) Operation of Powder Filling Device 1 of the Present Embodiment The operation of the powder filling device 1 of the present embodiment will be described with reference to FIGS. 5 to 7. First, the powder P is supplied into the main body 11 in a state where the main body 11 and the lid 12 are separated (FIG. 5 (a)). At this time, the powder P is placed on the grid member 15 provided in the opening 111, but for the reason described above, the powder P does not pass between the wires of the grid member 15 and fall.

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 cavity 22 of the filling target container 20 are aligned with each other. At the same time, the lid 12 is placed on the main body 11. Then, the 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. 5 (b)). As a result, 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 shaft at a constant speed by a motor, which is a drive source.

FIG. 6 shows how the shaft 132 rotates in a cross section perpendicular to the axis of the shaft 132. The gas flow path 1311 in the main body shown in the figure is connected to the gas supply pipe 14 on the supply source side in the upper part of the figure, and is connected to the gas supply pipe 123 in the lower part of the figure. The arrows shown by thick lines in the figure indicate the direction of rotation of the shaft 132, and the arrows indicated by thin lines indicate the flow of high-pressure gas. As shown in FIG. 6A, when the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft are not communicating with each other, the gas was supplied from the gas cylinder to the gas flow path 1311 in the main body through the gas supply pipe 14 on the supply source side. 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 beyond it. After that, as the shaft 132 rotates, a part of the gas flow path 1321 in the shaft communicates with the gas flow path 1311 in the main body (FIG. 6 (b)), and the high-pressure gas flows from the gas supply pipe 14 on the supply source side. It passes through the gas flow path 1321 in the shaft and is supplied to the powder storage chamber 10 through the remaining portion of the gas flow path 1311 in the main body and the gas supply pipe 123. The amount of high-pressure gas supplied per unit time increases as the rotation angle advances after the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft start to communicate with each other, and the gas flow path 1311 in the main body and the gas flow in the shaft It becomes maximum when the angles of the roads 1321 match (FIG. 6 (c)), 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 half rotation of the shaft 132, and the high-pressure gas is repeatedly supplied to the powder storage chamber 10 at a cycle of 1/2 of the rotation cycle of the shaft 132. Further, although 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, the six gas flow paths 1311 in the main body and the gas flow path 1321 in the shaft are arranged in parallel. Moreover, since the gas flow path 1321 in the shaft is orthogonal to the axis on which the shaft 132 rotates, all the gas flow paths 1321 in the shaft start and end communication with the gas flow path 1311 in the main body 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 slightly later than the timing of supply air due to the exhaust resistance of the exhaust port 122. As a result, the pressure in the powder storage chamber 10 repeatedly rises and falls in the cycle. The powder P is repeatedly pushed downward (air tapping) by this pressure in the same cycle, 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). )). The pressure of the high-pressure gas may be appropriately determined by a person skilled in the art by conducting a preliminary experiment for each powder to be handled. Further, the ratio (duty ratio) of the time for supplying the 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 device 1 of the present embodiment. That is, it is determined by the length in the rotation direction, and this length may be designed after obtaining an appropriate duty ratio by conducting a preliminary experiment with a conventional powder filling device using a solenoid valve, for example.

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

Actually, when the filling target container 20 is arranged directly under the main body 11, there is a slight gap between the upper end of the cavity 22 of the filling target container 20 and the grid member 15 of the main body 11, so that the powder P is 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 smoothed so as to be flush with the upper surface of the filling 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 is lowered from the first scraping portion 361 to the third scraping portion 363. The powder P can be gradually scraped by moving the entire scraper 36 in the order of the first scraping portion 361, the second scraping portion 362, and the third scraping portion 363 so as to come into contact with the powder P. ..

According to the powder filling device 1 of the present embodiment, while the shaft 132 is rotating, all the gas flow paths 1321 in the shaft start and end communication with the gas flow path 1311 in the main body at the same timing, so that the powder In the accommodation 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 close to uniform, whereby the powder P can be uniformly filled in the filling target container 20. Further, it is possible to match the time when the pressure of the compressed gas supplied from each air supply port 121 becomes maximum. Therefore, the average value of the pressure in the powder storage chamber 10 can be increased, whereby the powder P can be filled in the filling container 20 at a high density.

(4) Deformation Example of Powder Filling Device of This Embodiment FIG. 8 shows a modification of the powder filling device of this embodiment. The powder filling device 1A of this modified example comprises a silicone rubber film 126 stretched laterally inside the lid 12A of the powder storage chamber 10A, and a metal net provided directly under the film 126. A film suppressing member 127 is provided. Other than that, the configuration is the same as that of the powder filling device 1 described above.

The method of using the powder filling device 1A is the same as that of the powder filling device 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 film 126 but pushes the film 126 downward (single point chain line in FIG. 8), so that the compressed gas is below the film 126. The gas pushes the powder P, and similarly to the powder filling device 1, 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. Then, by using the film 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 film 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 scattered and clogged in the area of.

Without the film suppressing member 127, the film 126 may drop too much and come into contact with the powder P in the main body 11. When the film 126 comes into contact with the powder P, a compressive force acts directly on the powder P to produce a density distribution. Therefore, by providing the film suppressing member 127 under the film 126 in the lid 12A, the film 126 is prevented from coming into contact with the powder P.

The material of the film 126 is not limited to silicone rubber as long as it has flexibility, and for example, polyurethane or the like can be used. Further, 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 through, and is not limited to a net, for example, a large number of plate materials. It may be a perforated material, a rod material arranged side by side, or the like.

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 directly arranging the filling target container 20 under the main body 11. The spacer 30 may be used not only in the powder filling device 1A of the modified example but also in the powder filling device 1 described above. The spacer 30 is a plate material in which 18 through holes 31 are provided in the same shape and arrangement as the openings 111, and a sealing material 32 is provided on the lower surface so as to surround the entire 18 through holes 31. is there. When the powder is filled in the filling container 20, the filling container 20, the spacer 30 and the main body 11 are stacked in this order from the bottom so that the cavities 22, the through holes 31 and the openings 111 are aligned. When 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 pressing cylinder 124, the lid 12 and the main body 11, the main body 11 and the spacer 30, and the spacer 30 are formed. The airtightness between the filling target containers 20 is ensured by the upper sealing material 113, the lower sealing material 112, and the sealing material 32, respectively.

By using the spacer 30 in this way, the powder P can be filled in the cavity 22 at a higher density as described below. When the powder P is filled in the cavity 22 by the powder filling device 1 or 1A using the spacer 30, the powder P is filled together with the cavity 22 of the container 20 to be filled up to the through hole 31 aligned with the cavity 22. .. Then, the powder P protruding from the upper end of the through hole 31 is removed by the scraper 36 (FIG. 9A), and then 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. As a result, the powder P in the through hole 31 is pushed into the cavity 22 of the container 20 to be filled (FIG. 9 (b)). As a result, the cavity 22 is filled with the powder P at a higher density than that at the time of filling by the powder filling device 1 or 1A.

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

The results of this experiment are shown in FIG. 10 (a) for the powder filling device 1A of the present embodiment and in FIG. 10 (b) for the powder filling device using the solenoid valve of the comparative example. (a) shows the measurement results with five gas supply pipes 123, and (b) shows the 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 almost the same flow rate changes from each of the five gas supply pipes 123 over the same time. It can be seen that the gas is supplied to the powder storage chamber 10A. In addition, the value of the flow rate when the flow rate reaches its peak is almost the same at all peaks. On the other hand, in the comparative example, the value of the flow rate when the flow rate reaches its peak is different for each gas supply pipe 123, and the value of the flow rate is different for each peak even in the same gas supply pipe 123. Further, in the comparative example, the time when the flow rate peaks (specified by the time from the start of the flow rate measurement in FIG. 10) is also slightly different for each gas supply pipe 123. It is considered that the data of these comparative examples is due to the fact that it is difficult to open and close each solenoid valve at the same opening and timing. On the other hand, in the powder filling device 1A of the present embodiment, since the gas flow paths 1311 in each main body of the valve device 13 are opened at the same opening degree and at the same timing, the same problem as that of the solenoid valve does not occur.

FIG. 11 shows the results of measuring the pressure in the powder storage chamber 10A by periodically supplying the compressed gas into the powder storage chamber 10A under the same conditions as above for the powder filling device 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 rises and falls in accordance with the cycle of the supply of the compressed gas by the valve device 13 on both the upper side and the lower side of the membrane 126.

In FIG. 12, a plurality of devices having different pressures of compressed gas are used in the powder filling device 1A of the present embodiment by increasing the number of air supply ports 121 to 14 (the number of exhaust ports 122 is the same as the above example). An experiment was conducted in which the container 20 to be filled was filled with an alloy powder of RFeB-based magnet having an average particle size of about 3 μm, and the average value of the filling density of the powder in the 18 cavities of the container 20 to be filled and the powder supply were performed. The result of the experiment to find the variation of the weight is shown. From this experimental result, when 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 of the powder feed weight for each cavity is 0.3 g (filling density). It can be seen that the variation can be suppressed to less than 0.145 g / cm ^3).

Therefore, when the target value of packing density is 3.3 g / cm ³ (compressed gas pressure is 0.53 MPa) and 3.5 g / cm ³ (0.63 MPa), experiments are conducted 5 times each, and the packing density at each time is determined. The variation of the average value and the powdered weight was calculated. 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 each case, the reproducibility was good in 5 experiments, the average value was obtained with almost no deviation from the target filling 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 are shown for two examples in which the cross-sectional shapes of the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft are different. Here, the cross-sectional shapes of the gas flow path 1311 in the main body and the gas flow path 1321 in the shaft are rectangular 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. The experimental subjects were Example A and Example B in which the long side was 6.5 mm longer than Example A and the short side was 3.8 mm shorter than Example A. 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 pressure of the compressed gas (0.4 MPa) and the valve opening / closing cycle (80 msec) were the same in Example A and Example B. The number of air supply ports 121 was 10, and the number of exhaust ports 122 was the same as in 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 a time of 100 msec, which is slightly longer than one cycle, for Examples A and B. It can be seen that in Example B, the pressure rise in the powder storage chamber 10A is faster and the time for which the pressure is applied is shorter in Example B than in Example A. This result shows that Example B, which has a long long side, is more effective in applying pressure and opening.

FIG. 16 shows the results of measuring the filling density of the powder in the filling container 20 in a plurality of cases where the valve opening / closing cycles are different for Examples A and B. When the valve opening / closing cycle was the longest (100 msec), the filling densities of Example A and Example B were almost the same, but when the cycle was shorter than that, Example B was more than Example A. The packing density was higher. It is considered that this is because Example B is more effective in applying pressure and opening.

(6) Embodiment of Sintered Magnet Manufacturing Equipment and Sintered Magnet Manufacturing Method Next, an embodiment of the sintered magnet manufacturing apparatus and 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, the reference numeral is only “1”), a powder densification apparatus 42, a lid attachment portion 43, and an alignment apparatus. It has a (alignment portion) 44 and a sintering furnace (sintering portion) 45. Further, 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 attachment portion 43, the alignment device 44, and the sintering furnace 45. Of 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 the inert gas is separately supplied to the inside of the sintering furnace 45 as well. It has an inert gas atmosphere. By 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 device 1 to the sintering furnace 45 can be made into an oxygen-free atmosphere. In the powder filling device 1, a part of the gas supply pipe 14 on the supply source side and the gas supply source (not shown) are arranged outside the outer container 47. Since the valve device 13 is arranged in the outer container 47, the distance between the valve device 13 and the air supply port 121 can be shortened, and the pressure applied and the opening of the powder storage chamber 10 can be improved.

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

The alignment device 44 has a coil 441 and a container lifting device 442. The coil 441 has a shaft in a substantially vertical direction (vertical direction), and is arranged above the container elevating device 442. The container elevating device 442 is a device for elevating and lowering the filling target container 20 transported by the container transport device 46 to and from the inside of the coil 441.

The sintering furnace 45 has a sintering chamber 451 that accommodates a large number of containers 20 to be filled, a carry-in inlet 452 that communicates with the outer container 47, and a heat-insulating door 453 provided at the carry-in inlet 452.

The operation of the sintered magnet manufacturing apparatus 40 and one embodiment of 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 as described above, the cavity 22 of the filling target container 20 is filled with the alloy powder. The scraper 36 then removes excess powder from the top. Subsequently, the container to be filled 20 is conveyed to the lid attachment portion 43 by the container transport device 46, and the lid is attached to the container 20 to be filled. After that, the container 20 to be filled is conveyed to the alignment device 44 by the container transfer device 46, arranged in the coil 441 by the container elevating device 442 in the alignment device 44, and the powder in the container 20 to be filled by the magnetic field generated by the coil 441. Is oriented. After this alignment treatment, the container 20 to be filled is unloaded from the coil 441 by the container elevating device 442, transported to the sintering furnace 45 by the container transport device 46, and has a predetermined temperature (usually 800) in the sintering chamber 451. The powder in the container 20 to be filled 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, the sintered magnet is manufactured by the PLP method in which orientation and sintering are performed in a magnetic field without performing compression molding. The magnet.

Up to this point, 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, but it goes without saying that the present invention is not limited to each of the above embodiments, and the present invention is not limited to the above embodiments. Various modifications are possible within the scope of the gist.

1, 1A ... Powder filling device 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 paths 12, 12A ... Powder storage chamber lid 121 ... Air supply port 122 ... Exhaust port 123 ... Gas supply pipe 124 ... Cylinder 126 ... Film 127 ... Film suppressing member 13 ... Valve device 131 ... Valve body 1311 ... Gas flow path in the main body 1312 ... Shaft fitting hole 132 ... Shaft 1321 ... Gas flow path in the shaft 14 ... Supply 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 ... Scraping part 40 ... Sintered magnet manufacturing device 43 ... Lid mounting part 44 ... Alignment device 441 ... Coil 442 ... Container lifting device 45 ... Sinter furnace 451 ... Sinter chamber 452 ... Carry-in entrance 453 ... Sinter chamber door 46 ... Container transport device 47 ... Outer container

Claims (5)

a) An opening provided with a grid member at the lower end, and a powder storage chamber main body having a connection portion for airtightly connecting to the container to be filled at the opening.
b) With the lid attached to the ceiling of the powder storage chamber body,
c) Multiple gas supply pipes connected to the lid,
d) A valve main body provided so that a plurality of gas flow paths in the main body connected to the plurality of gas supply pipes penetrate the inside independently of each other.
e) inside the valve body, a cylindrical shaft insertion holes provided so as to cross all the gas flow path of the plurality of body,
f) and rotatably fitted to a cylindrical shaft to the shaft insertion hole,
g) A gas flow path in the shaft provided on the shaft corresponding to each of the plurality of gas flow paths in the main body, and a gas flow path in the shaft.
h) A plurality of source-side gas supply pipes for connecting the plurality of gas flow paths in the main body to the gas supply source are provided .
A powder filling device characterized in that the shape of the cross section of the gas flow path in the main body and the gas flow path in the shaft is a rectangle having two sides parallel to the axis of the shaft. The powder filling device according to claim 1, wherein the two sides are long sides of the rectangle. Wherein provided on the lid and the boundary of said powder housing chamber body, a seal member expands by sealing gas is supplied,
A seal gas supply path for supplying sealing gas to said sealing member,
Powder filling device according to claim 1 or 2, characterized by further comprising a pressing mechanism for pressing the powder receiving chamber body and the lid to each other. The powder filling device according to any one of claims 1 to 3.
The powder as a raw material for the sintered magnet, which is filled in the container to be filled by the powder filling device, is still filled in the container to be filled, and a magnetic field is applied to the powder without applying mechanical pressure. An alignment part that orients the powder by applying the powder,
A sintered portion that sinters the powder by heating the powder without applying mechanical pressure while the powder is still filled in the container to be filled.
A sintered magnet manufacturing apparatus, which comprises. A powder filling step of filling a container to be filled with powder as a raw material for a sintered magnet using the powder filling device according to any one of claims 1 to 3.
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 method for producing a sintered magnet, which comprises performing a sintering step of sintering the powder by heating the powder without applying mechanical pressure while the powder is still filled in the container to be filled. ..

Images