JPH0530875Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a powder molding machine for molding powder metallurgy materials.

[Technical background of the invention and its problems]

Generally, when forming a powder metallurgical material such as fuel pellets for a nuclear reactor, powder supplied into a die is compressed and formed using upper and lower punches.

FIG. 2 is a longitudinal sectional view of a powder molding machine, particularly a rotary type powder molding machine, for performing compression molding as described above. A shaft 3 is erected. A vertical shaft oil receiver 4 is fixedly installed on the upper surface of the frame 1 concentrically with the vertical shaft 3, and further above the vertical shaft oil receiver 4, a rotary disk 5 is mounted relative to the vertical shaft 3. It is rotatably mounted.

The rotary disk 5 has an upper flange portion 5a, a center flange portion 5b, and a lower flange portion 5c integrally formed on its outer periphery, and the center flange portion 5b has a shape as shown in FIG. A large number of dies 6 are provided in the circumferential direction. Further, upper punches 7 are vertically movably disposed on the upper flange-shaped portion 5a on the same axis as the dies 6, and lower punches 7 are also provided on the lower flange-shaped portion 5c on the same axis as the dies 6. A punch 8 is arranged to be movable up and down, and a drive gear 10 driven by an appropriate drive mechanism is meshed with a gear 9 formed on the outer periphery of the lower flange-shaped portion 5c.

On the other hand, a guide roller 11 is attached to the lower punch 8 on the outside of the portion protruding downward from the rotary disk 5, and the guide roller 11 is arranged on the frame 1 over a predetermined range in the circumferential direction. It is engaged with a guide groove 12 provided therein. Also, upper punch 7
Guide rollers 13 are also installed on both sides of the portion of the rotary disk 5 that protrudes upward from the rotary disk 5.
It is engaged with a guide groove 14 disposed over a predetermined range in the circumferential direction at a higher position.

In addition, in the pressurizing stroke section where the upper punch 7 and the lower punch 8 are inserted into the die 6 from above and below, and the powder raw material supplied into the die 6 is compression-molded, the top end of the upper punch 7 and the lower punch 8 are inserted into the die 6 from above and below. Pressure rollers 15 and 16 are disposed, respectively, in contact with the lower ends of the punches and apply pressure to both punches. Note that the reference numeral 17 in FIG. 2 is a powder feeder.

Thus, when compressing powder, the rotary disk 5 is rotated via the drive gear 10, and at the same time, the powder is fed from the powder feeder 17 into the die 6 which has come to a predetermined position. Therefore, according to the rotation of the rotary disk 5, the lower punch 8 is moved upward via the guide groove 12 and the guide roller 11 to reach a predetermined filling depth, and after removing the excess powder, the upper punch 7 is gradually lowered, and the powder in the die 6 is held between the upper and lower punches 7 and 8. In this way, both the upper and lower punches 7 and 8, which hold the powder in the die 6, press the pressure roller 1.
5, 16, the pressure roller 15,
16, both the upper and lower punches 7 and 8 are pressed in a direction toward each other, and compression molding of the powder is performed.

When the pressurizing process is completed in this manner, the upper and lower punches 7 and 8 are moved upward with the molded product being held between the upper and lower punches 7 and 8, so that the upper surface of the lower punch 8 becomes the upper surface of the die 6 (die table). When the upper punch 7 becomes flush with the upper punch 7, the upper punch 7 is moved further upward, and the molded product is then discharged. Thereafter, compression molding of the powder is sequentially performed within each die 6 in the same manner.

By the way, in such a powder molding machine,
In order to prevent powder from adhering to the inside of the die and reduce the frictional resistance of the compact, as well as to ensure smooth insertion and removal of the punch, a small pump applies constant pressure from the outside through a hole in the center of the lower punch. lubricant is supplied to the inner surface of the die.

By the way, molded objects such as fuel pellets are generally small, with a diameter of about 10 mm and a height of about 10 mm, and depending on the type of powder, if too much lubricant is supplied into the die, the molding may be difficult. Excessive lubricant is applied to the upper part of the body, particularly to the outer circumference of the upper end where the pressurizing force is relatively small, and the strength of the upper end of the molded body is weak, making it easy to break, and even after sintering, there is a high possibility that the product will be defective. Therefore, the amount of lubricant supplied must be extremely small. However, in rotary presses and molding machines that mold many molded objects at the same time, as mentioned above, both have a large number of dies, so valves are installed to reduce the amount of lubricant supplied into each die. Alternatively, even if an attempt is made to reduce the diameter of the piping, it is extremely difficult to supply the same amount of lubricant into each die due to differences in the length of the piping, etc., and the amount of lubricant must be adjusted using a valve. It is also extremely difficult.

[Purpose of invention]

In view of these points, the present invention makes it possible to always maintain an appropriate amount of lubricant supplied into the die during powder compaction, without causing excess or deficiency, and in particular, to prevent the supply of lubricant into the die at the upper end of the compact. It is an object of the present invention to provide a powder compacting machine which is prevented from chipping due to excessive supply of lubricant.

[Summary of the idea]

The present invention is a powder molding machine in which the powder supplied into the die is compression-molded by both upper and lower punches, and lubricant is supplied to the inner surface of the die through the lower punch. The present invention is characterized in that a lubricant discharge port is provided extending in the radial direction, and a means is provided for applying lubricant to the inner surface of the die only during the entire downward stroke of the lower punch as it descends within the die.

[Example of idea]

An embodiment of the present invention will be described below with reference to FIG. Note that the same parts as in FIG. 2 are given the same reference numerals, and detailed explanation thereof will be omitted.

In FIG. 1, reference numeral 20 is a lubricant supply hole provided in the vertical shaft 3 in the axial direction, and one end of which is connected to a pressure gauge, an automatic lubricant supply pump, and a lubricant tank (none of which are shown). The lubricant supply hole 20 is communicated with a circumferential groove 22 formed on the outer periphery of the vertical shaft 3 via a radial communication hole 21. On the other hand, a lubricant supply path 23 is formed in the rotary disk 5 and communicates with the circumferential groove 22 and extends in the radial direction corresponding to each of the dies 6.
3 are connected to the rotary disk 5 through pipes 24, respectively.
The lubricant supply amount adjusting valve 25 is connected to the suction port side of the lubricant supply amount adjusting valve 25, which is provided on the outer periphery of the lubricant supply amount in correspondence with each die 6 and opens only during the entire downward stroke of each lower punch 8 when the lower punch 8 descends. Further, a lower punch lubricant supply hole 26 extending in the axial direction is bored in the lower punch 8, and a pipe 2 is connected to the discharge port side of the lubricant supply amount adjustment valve 25 in this lower punch lubricant supply hole 26.
Further, the lower punch lubricant supply hole 26 is communicated with a lubricant discharge port 28 radially formed at the top of the lower punch 8.

Therefore, in response to the rotation of the rotary disk 5, the die 6 is rotated.
When raw material powder is supplied into the die table and the powder is pressure-formed by the movement of the upper and lower punches 7 and 8, the molded product is placed on the upper surface of the die table while being held between the upper and lower punches 7 and 8. After that, the upper punch 7 further moves upward, and is then dispensed from the die table to a predetermined location by an appropriate dispensing mechanism.

Then, the lower punch 8 begins to descend and prepares for the next powder filling, but in response to the lower stroke of the lower punch 8, the lubricant supply amount adjustment valve 25 opens, and the lubricant supply amount adjustment valve 25 is opened, and the lubricant is supplied through the lubricant supply hole 20, etc. The lubricant is supplied to the inner surface of the die 6 from the lubricant discharge port 28 provided at the top of the lower punch 8, and when the downward stroke is completed, the supply of the lubricant is stopped and the die 6 is released for the next processing. Powder is supplied into the chamber.

In the above embodiment, the lubricant supply amount adjusting valve 25 is opened and closed, but the circumferential groove 22 formed on the outer periphery of the vertical shaft
The lubricant supply path 2 is opened only during the downward stroke of the lower punch 8.
Even if it extends only in a predetermined range in the circumferential direction so as to communicate with 3, the same effect can be achieved.

[Effect of idea]

As explained above, in the present invention, a radially extending lubricant discharge port is provided only at the top of the lower punch, and the lubricant is supplied to the inner surface of the die only during the entire downward stroke of the lower punch as it descends within the die. As the lower punch is lowered, the lubricant is applied to the inside of the die sequentially from the upper end to the lower end, thereby lubricating the entire inner surface of the die. The agent is applied evenly. Moreover, as mentioned above, the lubricant is supplied during the downward stroke of the lower punch, so there is no need for a special lubricant application process, and the lubricant can be supplied in a relatively short time, allowing the valve opening to be adjusted. There is almost no influence of lubrication, and the occurrence of defective products due to excessive lubrication can be extremely reduced.

[Brief explanation of the drawing]

FIG. 1 is an enlarged longitudinal sectional view of a powder compacting machine according to the present invention, FIG. 2 is a vertical sectional view showing a schematic configuration of the powder compacting machine, and FIG. 3 is a plan view of a die plate portion. 3... Vertical shaft, 5... Turntable, 6... Dice, 7... Upper punch, 8... Lower punch, 20...
Lubricant supply hole, 25...Lubricant supply amount adjustment valve, 28...Lubricant discharge port.

Claims (1)

[Scope of utility model registration request] In a powder molding machine, the powder supplied into the die is compression-molded by upper and lower punches, and lubricant is supplied to the inner surface of the die through a lubricant supply hole formed in the lower punch, A lubricant discharge port extending in the radial direction is provided only at the top of the lower punch, and means is provided for applying lubricant to the inner surface of the die only during the entire downward stroke of the lower punch as it descends within the die. Features: Powder molding machine.