JP3434182B2 - Powder filling method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a powder filling method for filling powder into a cavity from a powder box.

[0002]

2. Description of the Related Art Conventionally, drop-filling has been known in which powder in a powder box is dropped into a cavity. However, if the shape of the cavity is complicated, a portion where the powder is difficult to fill may be generated, and the particle size of the powder may be small. Segregation of components may occur.
As a method for preventing this, the applicant of the present application has filed Japanese Patent Application No. 8-
No. 75945 (filed on March 29, 1996), a pipe having a plurality of holes is arranged in the powder box, and gas is caused to flow out from the holes to give fluidity to the powder in the powder box, while the pipe is placed in the cavity. A method of filling powder was proposed.

[0003]

However, fluidity is imparted to the powder only when it is inside the powder box, and the state when the powder is dropped into the cavity (such as fine powder flying up).
Depending on the shape of the cavity and the shape of the cavity (with undercut, etc.), the powder after being dropped into the cavity may not be uniformly packed due to particle size and component segregation or unfilled parts. Absent. Also, as the powder is filled in the powder box, the amount of gas supplied to the powder box decreases and the fluidity of the powder decreases due to the powder clogged in the holes in the pipe that let the gas flow into the powder box. May be compromised and uniform filling of the cavity may be compromised. It is an object of the present invention to provide a powder filling method that ensures uniform filling of powder into cavities.

[0004]

The present invention which achieves the above object is as follows. (1) The powder box is placed on a cavity while allowing gas to flow out from at least one pipe having a plurality of gas outlets and at least a part of which can be moved up and down to impart fluidity to the powder in the powder box. Moving and dropping the powder in the powder box into the cavity to fill the cavity; and moving the at least a part of the at least one pipe in the powder box up and down in the cavity. A step of inserting the powder into the powder filled therein and causing the gas to flow out to impart fluidity to the powder in the cavity to make the packing density uniform. (2) While the gas is caused to flow out from at least one pipe having a plurality of gas outlets to impart fluidity to the powder in the powder box, the powder box is moved onto a cavern to remove the powder in the powder box. In the powder filling method of dropping into the cavity and filling the cavity, the flow velocity of gas passing through the inlet side of the gas outlet is set to a flow velocity effective for preventing the powder from entering the pipe. And the flow velocity when the gas passes through the outlet side of the gas outlet is lower than the flow velocity when passing through the inlet side of the gas outlet to prevent the powder from scattering and make the packing density uniform. And a step of adjusting the flow rate to be reduced.

In the powder filling method of the above (1), the pipe is lowered from the powder box and inserted into the powder filled in the cavity, and the gas is discharged from the gas outlet to fill the cavity. The powder again recovers its fluidity and rearrangement of the powder occurs, so that the powder in the cavity can have a more uniform packing density. In the powder filling method of the above (2), the speed at which the gas passes through the gas outlet is changed to prevent the powder from entering the pipe at the inlet side of the gas outlet and preventing the powder from clogging. Scattering of powder on the side,
Prevents soaring and promotes uniform filling. Conventionally, it was thought that it was difficult to satisfy both hole clogging and uniform filling at the same time, but the method (2) can do so.

[0006]

FIG. 1 shows an apparatus for carrying out the method of the first embodiment of the present invention, and FIGS. 2 and 3 show an apparatus for carrying out the method of the second embodiment of the present invention. In the figure, parts common to the first and second embodiments of the present invention are designated by the same reference numerals.

First, parts common to the apparatus for carrying out the methods of the first and second embodiments of the present invention will be described with reference to FIG. 1, for example. The apparatus for carrying out the method of the present invention (powder filling apparatus) is a powder box 2 with an open bottom, to which powder 6 is supplied.
And a cavity 5 into which the powder 6 in the powder box 2 is dropped and filled when the powder box 2 is moved upward, and the powder box 2
And at least one pipe 3 disposed therein. The pipe 3 has a plurality of gas outlets 4, and the portion of the pipe 3 in which the gas outlets 4 are formed is arranged at a position below the upper surface of the powder supplied to the powder box 2.

The powder 6 can be applied as long as it can be fluidized to some extent, and its kind, material and size may be arbitrary.
Further, it may be a mixed powder of powders different from each other in at least one of kind, material and size. For example, it may be a mixed powder for metallurgy, a ceramic powder, or the like, and the type thereof does not matter. The pipe 3 is supplied with gas (the type of gas is not limited, for example, air or nitrogen) from a gas source (not shown),
The gas supplied into the pipe 3 flows into the powder 6 through the gas outlet 4 and imparts fluidity to the powder 6.

The upper side of the powder box 2 is covered with a cover 2a, and a hose 11 for supplying the powder 6 into the powder box 2 is connected and opened in the cover 2a. The cavity 5 may have any structure and shape, but in the illustrated example, it is formed by the die 7, the lower punches 8 and 9, and the core rod 10. The table 1 is provided so as to be flush with the upper surface of the die 7, and the powder box 2 slides (slides) on a plane formed by the upper surface of the table 1 and the upper surface of the die 7. The upper surface of the die 7 constitutes the scraping surface of the cavity 5.

The common method part of the present invention implemented using the common device part is as follows. The powder 6 is supplied into the powder box 2, and in that state, gas is flown out from the pipe 3 through the gas outlet 4 to give the powder 6 fluidity. While maintaining this state, place the powder box 2 on the table 1 and the cavity 5
Move upwards. Since the bottom of the powder box 2 is open, when the powder box 2 reaches the cavity 5, the powder 6 in the powder box 2 falls into the cavity 5 by its own weight,
To be filled. Since the powder 6 is given flowability,
It is smoothly dropped into the cavity 5, and there is little rising of fine powder. Then, the powder box 2 is retracted from above the cavity, and a punch (not shown) descends toward the powder 6 in the cavity and presses the powder 6 in the cavity to solidify it to obtain a powder molded product. After taking out the powder molded product from the cavity, the powder box 2 is again advanced to the position above the cavity, and the above cycle is repeated to repeatedly manufacture the powder molded product.

Next, the structure and operation of the parts peculiar to each embodiment of the present invention will be described. An apparatus (powder filling apparatus) for carrying out the powder filling method according to the first embodiment of the present invention will be described with reference to FIG. At least 1 installed on the powder box 2
Each of the three pipes 3 has at least a part that is vertically movable 3B, and the other parts 3a do not move in the vertical direction. However, the entire pipe 3 can move up and down 3
It may consist of B. Since the pipe 3B is vertically movable, when the powder box 2 comes above the cavity 5, it can be lowered and inserted into the cavity 5 in the vertical direction.
The gas outlet 4 is formed in at least a portion of the pipe 3B to be inserted into the cavity 5. Pipe 3B
When the gas flows out from the gas outlet 4 of the pipe 3 </ b> B while being inserted into the cavity 5, the powder 6 filled in the cavity 5 is provided with fluidity.

In the powder filling method according to the first embodiment of the present invention, the gas is discharged from at least one pipe 3 having a plurality of gas outlets 4 and at least a part 3B of which is movable up and down, and the powder box 2 is provided. The powder box 2 is moved into the cavity 5 while the powder box 2 is made to flow, and the powder box 2 is moved to the cavity 5 so that the powder 6 in the powder box 2 is dropped into the cavity 5. When stopped at the upper side, the vertically movable pipe 3B of the pipe 3 in the powder box 2 is inserted into the powder 6 filled in the cavity 5, and the gas is caused to flow out through the gas outlet 4 of the vertically movable pipe 3B. And applying a fluidity to the powder 6 therein to make the packing density uniform.
While the gas is flowing out from the gas outlet 4 of the vertically movable pipe 3B, the gas may or may not be discharged from the gas outlet 4 of the vertically immovable pipe 3A.

The operation of the powder filling method according to the first embodiment of the present invention is as follows. Powder 6 after the gas is filled in the cavity 5 from the gas outlet 4 of the vertically movable pipe 3B
Powder 6 after the cavity is filled
Regains fluidity and rearrangement of the powder occurs, resulting in a more stable state. As a result, the powder 6 in the cavity 5
Becomes almost the same as the powder in the powder box 2, and a uniform packing density can be obtained. In particular, in a thin-walled powder molded product, by arranging the vertically movable pipe 3B in accordance with the shape of the cavity, a uniform packing density can be obtained even in the thin-walled portion. Further, it is possible to obtain a molded product with good runout accuracy. Further, in the undercut molding, by inserting the vertically movable pipe 3B in the vicinity of the undercut portion, it is possible to obtain a uniform packing density even in the undercut portion.

An apparatus (powder filling apparatus) for carrying out the powder filling method according to the second embodiment of the present invention will be described with reference to FIGS.
explain. At least one pipe 3 provided for the powder box 2 (a pipe made of only a pipe 3A that cannot move up and down, or a pipe 3 that has a pipe 3B that can move up and down in at least part thereof) may be used. ) Has a plurality of gas outlets 4. The portion of the pipe 3 where the gas outlet 4 is formed is arranged below the upper surface of the powder 6 supplied into the powder box 2, and the gas flowing out of the gas outlet 4 flows into the powder 6. The powder 6 in the powder box 2 is made fluid.

Each gas outlet 4 has an inlet 4a on the inner diameter surface of the pipe 3 and an outlet 4b on the outer diameter surface of the pipe 3.
The passage cross-sectional area of the outlet 4b of the gas outlet 4 is larger than the passage cross-sectional area of the inlet 4a of the gas outlet 4. The gas outlet 4 may have a passage cross-sectional area that is tapered or may be stepwisely expanded from the inlet 4a toward the outlet 4b. FIG. 2 and FIG. 3 show the case where the taper shape is enlarged.

The diameter of the passage at the inlet 4a of the gas outlet 4 is preferably smaller than the diameter of the powder 6 (in the case of mixed powder, the diameter of the powder having a smaller diameter). This is to prevent the powder from entering the pipe 3 through the gas outlet 4 or blocking the gas outlet 4 by increasing the flow velocity or by the physical relationship between the powder and the inlet diameter. . Further, the diameter of the outlet 4b of the gas outlet 4 is preferably selected to be a diameter that reduces the flow velocity of the gas that has passed through the inlet 4a to such an extent that the powder 2 in the powder box 2 does not fly or fly up. However, the diameter of the outlet 4b changes depending on the type, size, and specific gravity of the powder 6.

In the powder filling method of the second embodiment of the present invention, the gas is caused to flow out from at least one pipe 3 having a plurality of gas outlets 4 to give the powder 6 in the powder box 2 fluidity, and A powder filling method of moving the box 2 onto the cavities 5 to drop the powder 6 in the powder box 2 into the cavities 5 and filling the cavities 5, when the gas passes through the inlet 4a side of the gas outlet 4. Flow velocity V1 of powder 6 of pipe 3
And a flow velocity V2 when the gas passes through the gas outlet 4b side of the gas outlet 4.
Is lower than the flow velocity when passing through the inlet 4a side of the gas outlet 4, so that the powder 6 is prevented from scattering and the filling density is made uniform.

The operation of the powder filling method of the second embodiment of the present invention is as follows. In order to improve the fluidity of the powder 6, it is advantageous that the air rate value (= gas flow rate / powder volume) is large. However, when filling a mixed powder of coarse powder (for example, iron powder) and fine powder (for example, graphite powder), increasing the air rate value, that is, increasing the air flow rate, causes the fine powder to scatter (fly up). ), The composition of the mixed powder becomes non-uniform, and the aerate value cannot be increased. However, in the method of the second embodiment of the present invention, by making the diameter of the gas outlet 4 larger on the pipe outer diameter side than on the pipe inner diameter side, the gas flow velocity V1 on the inlet 4a side is increased.
The gas flow rate V2 on the outlet 4b side can be made smaller than that of the above, and a large air rate value can be obtained without scattering even fine particles. Further, the diffusion of the outflow gas is made more uniform. Furthermore, since the gas flow velocity V1 on the inlet 4a side can be increased, it is possible to prevent fine powder from entering the pipe 3.

[0019]

According to the powder filling method of the first aspect, the pipe is lowered from the powder box and inserted into the powder filled in the cavity, and the gas is discharged from the gas outlet, whereby the inside of the cavity is discharged. It is possible to give fluidity to the powder filled in the second stage to cause rearrangement of the powder, and the powder in the cavity can have a more uniform packing density. According to the powder filling method of claim 2, the speed at which the gas passes through the gas outlet is changed to prevent the powder from entering the pipe and clogging the holes at the inlet side of the gas outlet. It is possible to prevent the powder from scattering and rising on the outflow side and promote uniform filling.

[Brief description of drawings]

FIG. 1 is a sectional view of an apparatus for carrying out a powder filling method according to a first embodiment of the present invention.

FIG. 2 is a sectional view of a pipe in an apparatus for carrying out the powder filling method according to the second embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of a portion A of FIG.

[Explanation of symbols]

1 table 2 powder boxes 2a cover 3 pipes 3A vertically movable pipe 3B Vertical immovable pipe 4 gas outlet 4a entrance 4b exit 5 cavities 6 powder 7 dice 8, 9 lower punch 10 core rod 11 hose

Front Page Continuation (72) Inventor Hiroshi Okajima 1 Toyota-cho, Toyota City, Aichi Prefecture Toyota Motor Co., Ltd. (72) Inventor Mikio Kondo, Nagakute-cho, Aichi-gun, Aichi Prefecture 1 41, Yokodoko, Toyota Chuo In the laboratory (56) Reference Japanese Patent Laid-Open No. 9-168898 (JP, A) Fukuikai 3-47691 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B30B 11/00 B22F 3/035

Claims (2)

(57) [Claims] 1. A powder box containing a plurality of gas outlets, at least a part of which is movable up and down, to allow gas to flow out of the powder box so as to impart fluidity to the powder in the powder box. A step of moving the powder in the powder box into the cavity and filling the cavity with the powder, and at least a part of the at least one pipe in the powder box that is movable up and down. A step of inserting into the powder filled in the cavity to let out a gas to give fluidity to the powder in the cavity to make the packing density uniform, and a powder filling method. 2. At least one having a plurality of gas outlets
While flowing gas from the two pipes to give fluidity to the powder in the powder box, the powder box is moved to a cavity and the powder in the powder box is dropped into the cavity to be filled in the cavity. A filling method, wherein the flow velocity of the gas passing through the inlet side of the gas outlet is set to a velocity effective for preventing the powder from entering the pipe, and the gas is at the outlet of the gas outlet. Side, the flow velocity when passing through the gas flow outlet is made lower than the flow velocity when passing through the inlet side of the gas outlet, and the flow velocity is set so as to prevent the powder from scattering and make the filling density uniform. Method.