JP2003034807A - Device and method for feeding rare-earth alloy powder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for feeding rare-earth alloy powder, which can feed even an alloy powder difficult to handle, such as the rare-earth alloy powder, into a cavity to be formed in a metal mold, from a powder feeding box having an opening in the bottom part, without fear for the firing, when feeding the rare-earth alloy powder into the cavity from the opening, while moving the powder feeding box. SOLUTION: The feeding device for feeding the rare-earth alloy powder into the cavity from the opening, while moving the powder feeding box 10 having the opening in the bottom part to above the cavity 4 to be formed in the metal mold, has an inert gas feeding device 16 for feeding an inert gas into the powder feeding box with a higher pressure than the atmospheric pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for supplying a rare earth alloy powder into a cavity of a mold and a method for supplying the rare earth alloy powder during press molding of a rare earth magnet, for example. The present invention relates to a supply device. More specifically, even if the alloy powder, such as the rare earth alloy powder, has poor fluidity and is difficult to be filled, and easily ignites and is difficult to handle, it does not cause lumps, bridges, or ignition, and is uniformly distributed in the cavity. TECHNICAL FIELD The present invention relates to a powder supply method capable of filling and supplying to powders and a supply device used for the method.

[0002]

2. Description of the Related Art Conventionally, in order to uniformly supply powder having poor fluidity from a powder feeding box into a cavity of a mold, a powder feeding box having an opening at the bottom is moved onto a cavity formed in the mold. A supply device is used in which the rare earth alloy powder is supplied from the opening into the cavity. In these powder feeders, rotary blades that rotate in the powder feeding box are used as shown in JP-B-59-40560, or as shown in JP-A-10-58198, the bottom portion in the powder feeding box is used. Using a spherical member that rotates at
As disclosed in Japanese Utility Model Laid-Open No. 63-110521, there is known one using a rotating blade that spirally rotates inside a powder feeding box.

[0003]

However, in the above-mentioned conventional method, the height of the powder feeding box becomes high and the punch stroke becomes long. Therefore, the time required for one press increases, and the productivity decreases. Moreover, with a powder having poor fluidity such as rare earth alloy powder, the cavity cannot be uniformly filled without a uniform pushing force. In particular, the rare-earth alloy powder by the strip casting method, which can obtain excellent magnetic properties when sintered, has a slender shape and has a narrow particle size distribution and a sharp shape, resulting in extremely poor fluidity and uniform It is difficult to fill it. Furthermore, when a lubricant such as a fatty acid ester is added to the rare earth alloy powder to improve the orientation, the alloy powder becomes viscous and uniform filling becomes more difficult. Further, in the device having the above configuration, since the surface of the die and the bottom of the powder feeding box are made of metal, the rare earth alloy powder can be sandwiched between them, and the rare earth alloy powder can be exposed to the atmosphere and ignite. There is also a nature. Therefore, the present invention, in the powder supply in which the powder feeding box having an opening at the bottom is moved onto the cavity formed in the mold to supply the powder from the powder feeding box into the cavity, the rare earth alloy powder Even if it is an alloy powder that is difficult to handle, there is no risk of ignition and the alloy powder can be supplied from the powder feeding box into the cavity with a more uniform pressure than the conventional stirring means. The purpose is to provide a device.

[0004]

In order to achieve the above-mentioned object, the powder feeding apparatus of the present invention has a powder feeding box having an opening at the bottom on a cavity formed in a mold as set forth in claim 1. A feeder for moving the rare earth alloy powder into the cavity through the opening, wherein the rare earth alloy powder feeder supplies the inert gas into the powder feeding box at a pressure higher than atmospheric pressure. It is characterized by comprising an inert gas supply device for Further, in the powder supply apparatus according to claim 2, a powder supply box having an opening at the bottom is moved onto the cavity formed in the mold to supply the rare earth alloy powder from the opening into the cavity. The device is characterized in that an inert gas supply device for supplying an inert gas into the powder supply box is provided above the central portion of the side wall of the powder supply box. A rare earth alloy powder supply apparatus according to a third aspect is the rare earth alloy powder supply apparatus according to the first or second aspect, wherein the powder feeding box slides on a die. Further, the rare earth alloy powder supply apparatus according to claim 4 is the rare earth alloy powder supply apparatus according to any one of claims 1 to 3, wherein the bottom of the powder supply box is horizontally opposed to the powder supply box. It is characterized in that a movable rod-shaped member is provided in the powder feeding box, and the rod-shaped member is used to press-fill the rare earth alloy powder into the cavity. Further, in the rare earth alloy powder supply device according to the fifth aspect, a powder feeding box having an opening at the bottom is moved onto a cavity formed in a mold, and the rare earth alloy powder is supplied from the opening into the cavity by gravity. The rare earth alloy powder supply device is characterized in that the rare earth alloy powder supply device comprises an inert gas supply device for continuously filling the powder supply box with an inert gas. Further, in the rare earth alloy powder supplying apparatus according to claim 6, in the rare earth alloy powder supplying method according to claim 5, a rod-shaped member that is movable in the horizontal direction relative to the powder feeding box at the bottom of the powder feeding box. The rod-shaped member is provided in the powder feeding box, and the rare earth alloy powder is pressed and filled in the cavity by the rod-shaped member. Further, according to the method for supplying rare earth alloy powder of the present invention, as described in claim 7, the powder feeding box having an opening at the bottom is moved onto the cavity formed in the mold, and the rare earth alloy powder is introduced into the cavity from the opening. Is a powder supply method adapted to supply the alloy powder into the cavity from the powder supply box, and then withdrawing the powder supply box in a direction orthogonal to the longitudinal direction of the cavity opening. .

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, the alloy powder in the powder feeding box is supplied into the cavity while the rod-shaped member is reciprocated horizontally at the bottom of the powder feeding box with respect to the powder feeding box. Therefore, the alloy powder in the powder feeding box can be filled in the cavity sequentially from the alloy powder existing in the vicinity of the bottom with a uniform pressure, and filling with a uniform density is possible without the occurrence of lumps and bridges. In particular, the rare earth alloy powder to which a lubricant is added, or manufactured by a strip casting method, even if the fluidity is poor, by the horizontal movement of the rod-shaped member, It is possible to fill the cavity with a uniform density.

The rod-shaped member may be a single rod, but if a plurality of rod-shaped members are provided at intervals in the horizontal direction, the rod can be filled more efficiently. Further, when a plurality of rod-shaped members are provided, if the intervals of the rod-shaped members are set to be substantially the same as the arrangement intervals of the cavities arranged in a plurality of rows along the arrangement direction of these rod-shaped members, each cavity arranged in a plurality of rows On the other hand, uniform filling can be performed by each rod-shaped member. Further, even if the final stop position after the parallel movement of the rod-shaped member is not set at a position removed from the opening surface of the cavity, each rod-shaped member stops at the same position for each cavity, There is no variation in the filling amount for each.

The rod-shaped member has a cross section of a triangle, a quadrangle,
A polygonal shape such as a pentagon is arbitrary. at least,
By making the cross section of the lower half that guides the alloy powder into an arc shape such as a circle or an ellipse, the alloy powder that contacts the rod-shaped member moves downward along the circumferential surface of the rod-shaped member as the rod-shaped member moves horizontally. While being guided into the cavity, it is possible to fill the cavity with an extremely uniform pressure. In this case, the diameter of the rod-shaped member is 0.3 to 7 m.
It is preferably m. This is because if it is less than 0.3 mm, the pushing force is insufficient, and if it exceeds 7 mm, the pressure applied to the alloy powder during horizontal movement becomes too strong and lumps are generated in the alloy powder. Further, it is preferable that the distance from the lower end of the rod-shaped member to the die surface at the peripheral edge of the opening of the cavity is 0.2 to 5 mm. This is because if it is less than 0.2 mm, the alloy powder is sandwiched between the die surface at the opening edge of the cavity and the rod-shaped member in a pressed state, and lumps are generated in the alloy powder, resulting in density variation in the cavity. I will end up. Also, 5 mm
This is because if the pressure exceeds the range, the pressing action of the alloy powder into the cavity with a uniform pressure cannot be obtained.

Further, by providing a rod-shaped member that moves in parallel in the powder feeding box in the horizontal direction above the rod-shaped member, it is possible to eliminate the unevenness of the alloy powder generated by the powder feeding in the powder feeding box. It is possible to make the filling pressure by gravity uniform. Moreover, the lumps generated in the alloy powder in the powder feeding box can be crushed.

Further, the final stop position after the parallel movement of the rod-shaped member is set to a position removed from the opening surface of the cavity, so that the final stop position after the parallel movement of the rod-shaped member is located on the opening surface of the cavity. It is possible to avoid that position. If stopped on the opening surface of the cavity, density variation occurs before and after in the moving direction of the rod-shaped member, but according to the present invention, a high density portion and a low density portion are formed in the rare earth alloy powder in the cavity. Can be prevented. Therefore, it is possible to prevent the molded body or the sintered body from cracking due to density variations.

Further, by providing a powder replenishing means for replenishing the amount of the alloy powder supplied from the powder feeding box into the cavity and reduced in amount, the alloy powder in the powder feeding box is always kept constant. As a result, the filling pressure by gravity can be kept constant, and as a result, the filling amount from the powder feeding box into the cavity can be made uniform.

Further, by providing an inert gas supply device for filling the inside of the powder feeding box with an inert gas, the alloy powder is kept in the cavity while keeping the inside of the powder feeding box filled with the inert gas. Therefore, frictional heat is generated along with the movement of the powder feeding box and the movement of the rod-shaped member to easily ignite, but there is no fear of ignition.

By attaching a fluororesin plate to the bottom surface of the powder feeding box, the risk of ignition can be further reduced. That is, the bottom surface of the powder feeding box is rubbed hard against the base plate and the die as the powder feeding box reciprocates, and the powder feeding box moves with the alloy powder sandwiched between the base plate and the die. . Therefore, a part of the alloy powder has the same metal as the side surface at the bottom of the powder feeding box, for example, stainless steel (SUS
304), the adhesion between the bottom surface of the powder feeding box and the base plate is poor, part of the alloy powder is trapped between the bottom surface of the powder feeding box and the base plate, and the inside of the powder container is filled with an inert gas atmosphere. Even if it is set, there is a high risk of ignition. Further, when a step is formed between the die and the die set, there is a risk of ignition due to sparks generated between the powder feeding box and the die set. Therefore, by attaching a plate material having good adhesion such as fluororesin, it is possible to prevent a part of the alloy powder from being caught between the bottom surface of the powder feeding box and the base plate, and the ignition does not occur.

Further, as shown in FIG. 14, it is preferable that the rod-shaped member 21 is translated in a direction orthogonal to the longitudinal direction of the opening of the cavity 4 formed by the die hole 2b of the die 2q and the lower punch 2. This is shown in FIGS.
As shown in FIG. 15, when the rod-shaped member 21 is moved in parallel along the longitudinal direction of the opening of the cavity 4, since the alloy powder m lacks dispersion fluidity, as shown in FIG. 15, the wall of the cavity 4 (die hole 1a Alloy powder m near the inner peripheral wall) of the rod-shaped member 21 is pulled in the moving direction as the rod-shaped member 21 moves, and as a result, the alloy powder m supplied into the cavity 4 is pulled.
This is because the filling amount tends to vary in the longitudinal direction of the opening. When the filling amount varies in the longitudinal direction of the opening in this manner, the sintered body after sintering also varies in size. When the rod-shaped member 21 is translated in a direction orthogonal to the longitudinal direction of the opening of the cavity 4, the distance between the walls of the cavity 4 located on the front side and the rear side in the moving direction of the rod-shaped member 21 is short. In addition, the movement of the alloy powder m in the cavity 4 is limited, so that the variation of the filling amount of the alloy powder m in the cavity 4 is unlikely to occur, and the variation of that degree is corrected by the press,
There is no dimensional variation in the sintered body after sintering.

The variation in the filling amount in the longitudinal direction of the opening of the cavity 4 also occurs when the powder feeding box is retracted. Therefore, by making the moving direction of the powder feeding box at the time of retreat also orthogonal to the longitudinal direction of the opening of the cavity 4, it is possible to suppress the variation of the filled alloy powder and reduce the variation of the size of the sintered body. it can.

When the powder feeding box is moved onto the cavity, the alloy powder can be held on the front side in the moving direction if the rod-shaped member is positioned on the tip side in the moving direction. Therefore, it is possible to prevent the alloy powder from moving and being biased toward the rear side in the traveling direction due to the movement of the powder feeding box, and to prevent the alloy powder from running short on the front side of the powder feeding box. Therefore, the filling pressure by gravity can be made uniform.

Further, as the powder feeding box moves, the alloy powder on the front side of the powder feeding box becomes insufficient, and the alloy powder on the rear side increases, so that when moving the powder feeding box onto the cavity. , If the center of the powder feeding box is moved to a position beyond the center of one or more cavities,
It becomes easy to fill the cavity with the alloy powder with a uniform pressure. Incidentally, even if the rare earth alloy powder has a lubricant added thereto and has viscosity and poor fluidity, the rare earth alloy powder is produced by a strip casting method. In addition, since the particle size distribution is narrow and sharp, even if the fluidity is extremely poor, according to the present invention, there is no fear of ignition, no lumps or bridges are formed, and an extremely uniform packing density is obtained. Therefore, the alloy powder can be supplied into the cavity.

[0017]

Embodiments of the present invention will now be described with reference to the drawings. The rare earth alloy powder used in this example was prepared as follows. First, US Pat. No. 5,383,9
Slabs were made using the strip cast method as shown in No. 78. Specifically, Nd: 30 wt%, B: 1.0 wt%, and Dy: produced by a known method.
1.2 wt%, Al: 0.2 wt%, Co: 0.9 wt
%, The balance Fe and the unavoidable impurities were used as a molten metal by high frequency melting. After keeping this melt at 1350 ° C., the roll peripheral speed was about 1 m / sec and the cooling speed was 500.
C. and a supercooling degree of 200.degree. C. were rapidly cooled on a single roll to obtain a flaky alloy ingot having a thickness of 0.3 mm.

Next, the alloy ingot was roughly pulverized by the hydrogen storage method and then finely pulverized in a nitrogen gas atmosphere using a jet mill to obtain an alloy powder having an average particle size of 3.5 μm. Next, in the rocking mixer, using the fatty acid ester as a lubricant to the obtained alloy powder,
0.3w of this diluted with petroleum solvent as a solvent
t% (lubricant base) was added and mixed to coat the surface of the alloy powder with the lubricant. Methyl caproate was used as the fatty acid ester and isoparaffin was used as the petroleum solvent. The weight ratio of methyl caproate and isoparaffin was 1: 9. As the composition of the rare earth alloy, in addition to the above, those described in US Pat. No. 4,770,423 can be adopted.

The type of the lubricant is not particularly limited, and for example, a fatty acid ester diluted with a solvent is used. Examples of the fatty acid ester include methyl caproate, methyl caprylate, methyl laurate, methyl laurate, and the like. Further, as the solvent, a petroleum solvent represented by isoparaffin or a naphthene solvent can be used, and a fatty acid ester:
A mixture of solvents in a weight ratio of 1:20 to 1: 1 is used. Also, a solid lubricant such as zinc stearate can be used in place of or in combination with the liquid lubricant.

FIG. 1 is a perspective view showing the overall structure of a press molding apparatus equipped with the rare earth alloy powder supply device of the present invention.
In the figure, 1 indicates a base plate, and this base plate 1
A die 2a is fitted into the die set 2 disposed adjacent to the die set 2, and the die 2a is provided with a die hole 2b penetrating in the vertical direction. The lower punch 3 is arranged so as to be fitted into the die hole 2b from below, and the cavity 4 having an arbitrary volume is formed by the inner peripheral surface of the die hole 2b and the upper end surface of the lower punch 3. In the figure, reference numeral 5 denotes an upper punch. After the alloy powder m is supplied into the cavity 4 by the powder feeding box 10, the powder feeding box 10 is withdrawn from above the cavity 4 to be immersed in the cavity 4 and alloyed with the lower punch 3. The powder m is compressed to form an alloy powder compact. In this embodiment, the cavity 4 is formed along the moving direction of the powder feeding box 10.
Two rows were arranged in each row, and six rows were provided.

A magnetic field generating coil 6 is arranged below the die 2a, and an orientation magnetic field is generated together with a magnetic field generating coil (not shown) provided in the vicinity of the upper punch 5 arranged on the die 2a. .

A powder feeding box 10 is provided on the base plate 1, and the powder feeding box 10 is configured to reciprocate between a die 2a and a standby position by a cylinder rod 11a of an air cylinder 11. Near the standby position of the powder supply box 10, a supply device 30 for supplying the rare earth alloy powder m to the powder supply box 10 is provided.

Explaining the details of the replenishing device 30, a feeder cup 32 is placed on a scale 31, and an alloy powder m is gradually dropped into the feeder cup 32 by a vibrating trough 33. . This weighing operation is performed while the powder feeding box 10 is moving on the die 2a, and is replenished by the robot 34 when returning to the standby position. Alloy powder m placed in the feeder cup 32
The amount of the alloy powder m in the powder feeding box 10 is reduced by one pressing operation so that the amount of the alloy powder m in the powder feeding box 10 is always constant. Thus, as a result of the amount of the alloy powder m in the powder feeding box 10 becoming constant, the pressure at the time of gravity falling into the cavity 4 becomes constant, and the amount of the alloy powder m filled in the cavity 4 becomes constant. .

3 to 5 show the details of the powder feeding box. FIG. 2 is a plan view, FIG. 3 is a side view, FIG. 4 is a bottom view, and FIG. 6 is a shaker mounted in the powder feeding box. FIG. The shaker 20 is fixed to two support rods 12, 12 extending in parallel through the side walls 10a, 10a facing the moving direction of the powder feeding box 10 via a connecting rod 22a. Both ends of the two support rods 12, 12 are fixed to the connecting members 13, 13 by screws. A second air cylinder 15 is fixed to a fixing member 14 attached to the outside of the right side wall 10a in the figure, and a cylinder shaft 15a of the air cylinder 15 is fixed to the right connecting member 13. Thus, the air supply pipe 1 is provided at both ends of the air cylinder 15.
Cylinder shaft 15 by the air supplied from 5b
The shaker 20 was made to reciprocate by the reciprocating motion of a.

A shaker 20 having a rod-shaped member 21 shown in detail in FIG. 6 as a perspective view is mounted in the powder feeding box 10. This rod-shaped member 21 has a diameter of 0.3 to 7
It is a round bar material having a circular cross section of mm, and three rods are arranged in parallel in the horizontal direction. The same number of rod-shaped members 21 having the same shape are provided above these rod-shaped members 21 via a support member 22. These rod-shaped members 21 are integrally formed in a frame shape, and the cylinder shaft 15a of the air cylinder 15 is provided.
The reciprocating motion of (1) makes it possible to reciprocate horizontally in the powder feeding box 10. In the present embodiment, the three rod-shaped members 21, 21, 21 are arranged in three rows in the moving direction of the powder feeding box 10, and two cavities 4, 4 and 4 are provided in a row. , Are arranged at the same distance as the arrangement interval of the three rows in the moving direction. In other words, the distance between the centers of the cavities 4, 4, 4 and the distance between the centers of the rod-shaped members 21 are substantially equal in the moving direction of the rod-shaped members 21. Thus, the final stop position after the parallel movement of the rod-shaped member 21 is set to the opening surface 4a of the cavity 4.
All cavities 4 when set to the position removed from
Therefore, the rod-shaped member is located off the opening surface 4a. Further, all the cavities 4 can be filled with the alloy powder m at the same density by the rod-shaped members 21.

The lower end of the lower rod-shaped member 21 is arranged at a position of 0.2 to 5 mm from the die surface at the peripheral edge of the cavity 4. Further, the rod-shaped member 21 and the supporting member 22 are made of stainless steel (SUS304).

An N ₂ gas supply pipe 16 for supplying an inert gas into the powder supply box 10 is provided above the center of the right side wall 10a of the powder supply box 10 as shown in FIG. The powder feeding box 10 is supplied at a pressure higher than the atmospheric pressure so as to keep the inside of the powder feeding box 10 in an inert gas atmosphere.
Therefore, when the shaker 20 reciprocates, the alloy powder m
Friction occurs between and but does not ignite. Even between the bottom surface of the powder feeding box 10 and the base plate 1, the powder feeding box 10 moves with the alloy powder m sandwiched, but it does not ignite due to friction. Further, as the powder feeding box moves, friction occurs between the powders in the powder feeding box, but the powders do not ignite.

Referring to FIG. 3, a lid 10d is provided so as to cover the powder container 10A of the powder feeding box 10 in an airtight manner.
The lid 10d is provided in the powder container 1 when the alloy powder m is replenished.
In order to open the top of OA, one must move to the right in the figure. Therefore, the third air cylinder 17 for driving to open the lid 10d is provided on the front side wall 1 in the drawing.
It is provided at 0b. The air cylinder 17 and the lid 10d are connected by a metal fitting 18 and are screwed together. This lid 1
0d is usually placed on the powder container 10A of the powder feeding box 10 to keep the inert gas atmosphere, and moves to the right only when the powder is replenished. A guide means 17a is provided on the side of the lid 10d facing the third air cylinder 17 so that the lid 10d can be smoothly moved when the lid 10d is driven to the open state by the third air cylinder 17. There is. Thus, the cylinder shaft (not shown) is driven by the air supplied from the air supply pipes 17b to both ends of the air cylinder 17 to open / close the lid 10d.

On the bottom surface of the powder feeding box 10, a plate material 19 made of fluororesin having a thickness of 5 mm is screwed and fixed, and the powder feeding box 10 is slid on the base plate 1 via the plate material 19 made of fluororesin. The alloy powder m was prevented from being caught between the powder feeding box 10 and the base plate 1 (die set 2).

Next, the powder supply using the above apparatus will be described. First, as shown in FIG. 1, an inert gas is introduced from the N ₂ gas supply pipe 16 into the powder container 10A of the powder feeding box 10. In this state, the lid 10 of the powder feeding box 10
d is opened, and a predetermined amount of alloy powder m measured in the feeder cup 31 by the robot 34 in the powder container 10A.
To supply. As shown in FIG. 7, after supplying the alloy powder m,
The lid 10d is closed to keep the inside of the powder container 10A in an inert gas atmosphere. The introduction of the inert gas into the powder container 10A is performed not only when the powder feeding box 10 moves on the cavity 4 but always, so that the risk of ignition of the alloy powder m is reduced. . Ar or He can also be used as the inert gas.

In this state, the air cylinder 11 is operated to move the powder feeding box 10 onto the cavity 4 of the die 2 as shown in FIG. At this time, as shown in the figure, the rod-shaped member 21 is moved in a state of being positioned on the front side in the moving direction side of the powder feeding box 10, so that the alloy powder m on the front side in the moving direction moves backward in the moving direction. The alloy powder m can be carried onto the cavity 4 in a state in which the alloy powder m is prevented from shifting to the side and the deviation is suppressed.

Further, as shown in the drawing, the center 1 of the powder feeding box 10
0c is moved to a position beyond the center 4c of the plurality of cavities 4 (moving direction side from the center of the cavity 4), the powder feeding box 1 is moved along with the movement of the powder feeding box 10.
Even if the alloy powder m on the front side in the moving direction of 0 becomes insufficient, the alloy powder m on the rear side in the moving direction becomes larger,
It becomes easy to fill the alloy powder m into the cavity 4 with a uniform pressure.

After positioning the powder feeding box 10 on the cavity 4 in this way, as shown in FIG. 9, the rod-shaped member 21 in the powder feeding box 10 is horizontally reciprocated, for example, 5 to 15 times. While moving, the alloy powder m in the powder feeding box 10 is filled in the lower cavity 4 in an inert gas atmosphere. Therefore, the alloy powder m can be supplied into each cavity 4 with an extremely uniform packing density without fear of ignition. The final stop position after the parallel movement of the rod-shaped member 21 is set to a position removed from the opening surface 4a of the cavity 4, and the alloy powder m is filled in each cavity 4 with a uniform density distribution. It will be.

Next, after the alloy powder m is filled and supplied into the cavite 4, the rod-shaped member 21 is fed into the powder feeding box 1 as shown in FIG.
0 to prevent the alloy powder m on the front side in the moving (backward) direction from shifting to the rear side in the moving (backward) direction, as shown in FIG.
Then, the upper punch 5 is lowered to press-form the alloy powder m in the cavity 4, as shown in FIG. During this period, the alloy powder m is supplied to the powder feeding box 10. In this way, the above operation is repeated to continuously press the alloy powder m.

In the present embodiment, the alloy powder m is supplied to the powder container 10A accurately from the feeder cup 32 by the amount reduced by the amount supplied to the cavity 4. The alloy powder m in the box 10 can be constantly maintained at a constant amount.
The inside can be supplied accurately.

Further, in this embodiment, since the fluororesin plate material 19 is attached to the bottom surface of the powder feeding box 10, the bottom surface of the powder feeding box 10 is in close contact with the sliding surface of the base plate 1, and a part of the alloy powder m is fed. It is possible to prevent the bottom surface of the powder box 10 from being caught between the base plate 1 and the alloy powder m to be supplied to the cavity 4 without fear of ignition.

By the above press molding, the orientation magnetic field was 1.0 T, the density of the compact was 4.4 g / cm ³ , and the length was 40.
A rectangular parallelepiped rare earth alloy powder compact having a size of 20 mm, a width of 20 mm, and a height of 30 mm was obtained. The compression molded body obtained as described above was transferred to a sintering furnace, sintered at 1050 ° C. for 2 hours in an Ar atmosphere, and further subjected to an aging treatment at 600 ° C. for 1 hour in an Ar atmosphere. A sintered magnet as shown in Japanese Patent No. 4,770,423 was obtained. The obtained sintered magnet is cracked,
There was no chip and the weight was uniform.

FIG. 13 shows the relationship between the diameter of the rod-shaped member 21 and the distance (gap) between the lower end of the rod-shaped member 21 on the lower side and the die surface. In this figure, the region surrounded by the two curves shows the range in which the alloy powder is packed at a uniform packing density without lumps or bridges. Above the region between the curved lines shown in the figure, the pushing force is insufficient and uniform filling cannot be performed, and below the region, lumps occur in the alloy powder. This was confirmed experimentally. As the experimental conditions, the same alloy powder as in the above example was used, the pressing apparatus of the above example was used, the orientation magnetic field was 1.0 T, the density of the compact was 4.4 g / cm ³ , and the length was 40.
A rectangular parallelepiped rare earth alloy powder compact having a size of 20 mm, a width of 20 mm, and a height of 30 mm was pressed four times to obtain a total of 24 pieces. This compact was sintered at 1050 ° C. for 2 hours in an Ar atmosphere, and further aged for 1 hour at 600 ° C. in an Ar atmosphere to obtain a sintered magnet. Then, the dimensions of the obtained sintered body were measured.
As a result, it is in the area surrounded by the two curves in FIG. 13 that all of the sintered bodies fall within an error of ± 2%.

[0039]

As described above, according to the rare earth alloy powder supply device and the powder supply method of the present invention, even if the alloy powder has extremely poor stirring property such as powder supply at the time of molding the rare earth magnet, it is possible to prevent ignition. With no fear, and without damaging or bridging, with a very uniform packing density,
Alloy powder can be fed into the cavity.

[Brief description of drawings]

FIG. 1 is a perspective view of an embodiment of a press molding apparatus equipped with the powder supply apparatus of the present invention.

FIG. 2 is a side sectional view in the vicinity of a powder feeding box of the press molding apparatus.

FIG. 3 is a plan view of the powder feeding box.

[Fig. 4] Side view of the powder feeding box

[Fig. 5] Bottom view of the powder feeding box

FIG. 6 is a perspective view of a rod-shaped member that constitutes the powder supply device.

FIG. 7 is a sectional view showing one step of supplying alloy powder.

FIG. 8 is a sectional view showing another step of supplying the alloy powder.

FIG. 9 is a sectional view showing another step of supplying the alloy powder.

FIG. 10 is a sectional view showing another step of supplying the alloy powder.

FIG. 11 is a sectional view showing another step of supplying the alloy powder.

FIG. 12 is a sectional view showing another step of supplying the alloy powder.

FIG. 13 is a characteristic diagram showing the relationship between the diameter of the rod-shaped member and the distance between the die surface and the lower end of the rod-shaped member.

FIG. 14 is a plan view showing a filling state of alloy powder.

FIG. 15 is a plan view showing a filling state of alloy powder.

FIG. 16 is a sectional view showing a filling state of alloy powder.

[Explanation of symbols]

1 Base Plate 2 Die Set 2a Die 2b Die Hole 3 Punch 4 Cavity 4a Opening 4c Center 5 Upper Punch 6 Magnetic Field Generating Coil 10 Powder Feeding Box 10a Sidewall 10b Sidewall 10c Center 10d Lid 10A Powder Storage 11 Air Cylinder 11a Cylinder Rod 12 Support Rod 13 Connecting Material 14 Fixing Metal Fitting 15 Second Air Cylinder 15a Cylinder Shaft 15b Air Supply Pipe 16 N ₂ Gas Supply Pipe 17 Air Cylinder 17a Guide Means 17b Air Supply Pipe 18 Metal Fitting 19 Fluororesin Plate 20 Shaker 21 Rod Member 22 Supporting Member 22a Connecting rod 30 Replenishing device 31 Scale 32 Feeder cup 33 Vibration trough 34 Robot m Alloy powder

Continued front page    (72) Inventor Yo Nakamura             2-15-17 Egawa, Shimamoto-cho, Mishima-gun, Osaka Prefecture             Sumitomo Special Metals Co., Ltd. Yamazaki Works F-term (reference) 4K018 AA11 AA27 CA14

Claims (7)

[Claims] 1. A supply device in which a powder feeding box having an opening at the bottom is moved onto a cavity formed in a mold to supply rare earth alloy powder from the opening into the cavity, wherein the rare earth metal The rare-earth alloy powder supply device is characterized in that the alloy powder supply device comprises an inert gas supply device for supplying an inert gas into the powder supply box at a pressure higher than atmospheric pressure. 2. A supply device in which a powder feeding box having an opening at the bottom is moved onto a cavity formed in a mold to supply the rare earth alloy powder from the opening into the cavity. A rare earth alloy powder supply device comprising an inert gas supply device for supplying an inert gas into the powder supply box above a central portion of a side wall of the powder box. 3. The rare earth alloy powder supplying apparatus according to claim 1, wherein the powder feeding box slides on a die. 4. A rod-shaped member, which is movable in the horizontal direction relative to the powder feeding box at the bottom of the powder feeding box, is provided in the powder feeding box, and the rod-shaped member press-fills the rare earth alloy powder into the cavity. The rare earth alloy powder supply device according to any one of claims 1 to 3, characterized in that. 5. A rare earth alloy powder supply device in which a powder feeding box having an opening at the bottom is moved onto a cavity formed in a mold and gravity feeds the rare earth alloy powder into the cavity through the opening. The rare earth alloy powder supply device further includes an inert gas supply device for continuously filling the powder supply box with an inert gas. 6. A rod-shaped member, which is movable in the horizontal direction relative to the powder feeding box at the bottom of the powder feeding box, is provided in the powder feeding box, and the rod-shaped member press-fills the rare earth alloy powder into the cavity. The rare earth alloy powder supply device according to claim 5, wherein 7. A powder supply method, wherein a powder feeding box having an opening at the bottom is moved onto a cavity formed in a mold to supply the rare earth alloy powder from the opening into the cavity. A method for supplying rare earth alloy powder, characterized in that, after supplying the alloy powder from the powder supply box into the cavity, the powder supply box is withdrawn in a direction orthogonal to the longitudinal direction of the cavity opening.