JP3499186B2 - Grinding device and grinding method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is manufactured using a crushing apparatus and a crushing method for crushing objects to be crushed by colliding the objects to be crushed in a crusher, and a powder obtained by this crushing method. Regarding a sintered body.

[0002]

2. Description of the Related Art A conventional crushing apparatus of this type crushes an object to be crushed, a raw material feeder for supplying the object to be crushed to the crusher, and a powder obtained by the crusher. The crusher includes a recovery tank, a nozzle that injects an inert gas at a high speed, and a classification rotor that classifies and removes the pulverized fine powder. Then, in the crusher, the objects to be crushed, which are charged from the raw material charging machine, collide with each other by the high-speed inert gas injected from the nozzle and are crushed. The pulverized powder is taken out from the classification rotor and collected in the collection tank. At this time, in order to make the particle size distribution of the powder collected in the collection tank the same, it is necessary to make the crushing conditions constant by collision in the crusher. Then, in order to keep the crushing conditions constant, it is necessary to always keep the amount of the object to be crushed in the crusher constant.

Therefore, conventionally, in order to always maintain a constant amount of the material to be crushed in the crusher, the amount of material to be crushed from the raw material charging machine is detected by detecting the weight change of the recovery tank. The method of adjusting is adopted. As a method other than the above, there is a method of detecting a motor load current for driving the classification rotor. This detection method is
When the counter flow rate of the crushed material in the crusher increases, the amount of the crushed material that collides with the classifying rotor increases, so it is used to increase the motor load. Reduce the amount of material to be crushed from the loading machine.

Further, as another method, a sensor for detecting the raw material level is inserted into the crusher to determine whether or not the crushed object has reached a predetermined level in the crusher, and reaches the predetermined level. If it is not possible to detect that the crushed object is being detected, there is a method of continuing to input the material to be crushed from the raw material feeding machine.

[0005]

However, in the above-mentioned conventional method, it was difficult to make the amount of stay of the material to be crushed in the crusher constant. That is, according to the method of detecting the weight of the recovery tank, the staying amount of the material to be ground that actually exists in the grinding machine is detected with a time lag. Therefore, because it is not possible to immediately detect that the crushed object has become less than the predetermined amount, not only is the supply timing of the crushed object delayed, but despite the fact that a sufficient crushed object has already been introduced, Furthermore, the material to be crushed will be added. In addition, the method of detecting the motor load current that drives the classification rotor has less problems due to the time lag as described above, compared to the method of detecting the weight of the recovery tank, but the change in the amount of crushed material is strictly determined. It cannot be detected as it can.

According to the method of providing the raw material level sensor in the crusher, it is possible to judge whether or not the crushed object has reached a predetermined amount without a time lag. However, it is not possible to determine how much crushed material should be added when the predetermined amount has not been reached. Therefore, if the material to be crushed is gradually fed in to reach a predetermined amount, the amount of the material to be crushed in the crusher is actually larger than the amount discharged from the crusher. There is a possibility that In order to eliminate such a possibility, if a large number of objects to be crushed are put in at one time, a predetermined amount is largely exceeded. further,
Since the material to be ground is rolled up in the grinder, the raw material level sensor cannot accurately detect the level of the material to be ground.

Therefore, a main object of the present invention is to provide a pulverizing apparatus and a pulverizing apparatus which can obtain a powder having a desired particle size distribution by keeping the amount of the pulverized material in the pulverizer constant, and this pulverizing. The object is to provide a molded body and a sintered body manufactured by using the powder obtained by the method.

[0008]

In order to achieve the above object, a crushing device according to claim 1 is a crusher for crushing a rare earth alloy, a raw material charging device for supplying a rare earth alloy to the crusher,
A recovery tank for recovering the powder obtained by the crusher, a weight detector for detecting the weight of the crusher in which the rare earth alloy has accumulated, and a first flexure provided between the raw material feeder and the crusher.
Shiburupaipu, it is provided between the grinder and the collection tank
The second flexible pipe, and a control unit for controlling the supply amount of the rare earth alloy to the crusher by proportional-plus-integral-derivative control so that the rare-earth alloy in the crusher has a constant amount based on the output from the weight detector. The machine is the crusher body,
A raw material charging pipe to be formed on the side of the crusher main body, and three supporting portions that are provided at equal intervals on the outer circumference of the crusher main body including
The raw material input pipe is through the first flexible pipe.
It is connected to the raw material feeding machine, and each support is connected to the raw material feeding pipe and powder.
It is arranged so as to support the crusher main body at a position above the connection with the crusher main body and above the center of gravity of the crusher , and the weight detector includes a detector provided at each support portion. .

[0009]

A crushing apparatus according to a second aspect is the crushing apparatus according to the first aspect, wherein the crusher further includes a classification rotor provided above the inside of the crusher main body and for classifying the powder. And

The crushing method according to claim 3 is a crushing method that uses a crusher that crushes the supplied object to be crushed and discharges the obtained powder to the outside, and retains in the crusher during crushing. The first set value corresponding to the weight of the crushed object,
A second set value corresponding to a weight greater than the weight of the crushed object corresponding to the first set value, and a third set value corresponding to a weight less than the weight of the crushed object corresponding to the first set value. The step of detecting the weight of the crusher in which the crushed object has been set and stayed with the weight detector, and when the crushed object is supplied to the crusher before the crushing operation of the crusher is started, the output from the weight detector and the The step of controlling the operation of supplying the crushed object to the crusher based on the 2 set values, the deviation is calculated based on the output from the weight detector and the first set value during the crushing operation of the crusher. , powder on the basis of the current deviation and the previous deviation
The method includes the steps of determining the supply amount of the crushed material to the crusher, and controlling the stop of the crushing operation of the crusher based on the output from the weight detector and the third set value.

[0012]

A crushing method according to a fourth aspect is the crushing method according to the third aspect, wherein the object to be crushed is a rare earth alloy. A sintered body according to a fifth aspect is characterized by being manufactured using the powder obtained by the pulverizing method according to the third aspect. In this specification, the “object to be crushed accumulated in the crusher” means the object to be crushed accumulated in the crusher.

In the crushing apparatus according to the first aspect of the present invention, the weight of the rare earth alloy retained in the crusher is detected by detecting the weight of the crusher in which the rare earth alloy which is the object to be crushed is detected. It is possible to detect the increase or decrease of the retained rare earth alloy without causing a time delay. Therefore, according to the present invention, the supply amount of the rare earth alloy to the crusher can be appropriately increased or decreased as compared with the case where the weight of the recovery tank for recovering the powder discharged from the crusher is measured. As a result, hunting due to overshoot can be eliminated and the amount of rare earth alloy in the crusher can be kept constant. Further, by detecting the weight, the weight deviation from the target set value can be detected. Therefore, the supply amount can be increased or decreased according to the deviation,
The amount of rare earth alloy in the grinder can be brought closer to the desired value more quickly. As a result, the particle size distribution of the recovered powder can be made substantially the same, and the powder having a desired particle size distribution can be obtained.

By controlling the supply amount of the rare earth alloy by the proportional-plus-integral-derivative control, it is possible to bring the amount of the rare-earth alloy in the crusher closer to a desired value and reduce the fluctuation. Therefore, the particle size of the powder can be maintained within a certain range. Further, by detecting the weight of the crusher using a plurality of detectors, the weight of the crusher can be accurately detected even if the weight of the crusher is tilted or biased to the weight detector. it can. Therefore, the rare earth alloy can be accurately supplied by providing a detector on each support.

Further, by supporting the crusher by three supporting portions at equal intervals, the crusher can be stably supported without rattling. Therefore, the weight of the crusher can be detected more accurately by the detector provided on each support portion. Further, by supporting the crusher main body at a position above the center of gravity of the crusher, tilting of the crusher can be prevented and the weight of the crusher can be accurately detected. In addition, by inserting the flexible pipe, the weight of the rare earth alloy retained in the crusher can be accurately detected without being affected by the amount of the rare earth alloy in the raw material feeder and the increase or decrease of the powder in the recovery tank. If the classifying rotor is arranged above the inside of the crusher main body as in the crushing apparatus according to the second aspect, the center of gravity of the crusher becomes high and the crusher easily tilts. Even with such a classification rotor, by supporting the crusher main body at a position higher than the center of gravity of the crusher, tilting of the crusher can be prevented and the weight of the crusher can be accurately detected.

In the crushing method according to the third aspect of the present invention, the supply amount of the crushed object is determined based on the deviation of this time and the deviation of the previous time, so that the quantity of the crushed object in the crusher can quickly reach a desired value. It is possible to supply the material to be crushed so that it approaches,
It is possible to prevent the particle size distribution of the powder from fluctuating by preventing the amount of the pulverized material in the pulverizer from greatly increasing or decreasing.

Further, not only during the crushing operation of the crusher but also during the supply of the crushed object before the crushing operation of the crusher is started, the crushed object to the crusher is output based on the output from the weight detector. You can control the supply. By setting the supply amount of the crushed object before the start of the crushing operation of the crusher to be larger than the weight of the crushed object that remains in the crusher during crushing, the crushed object that stays immediately Although it decreases, it is possible to compensate for the decrease in advance. Therefore, the particle size distribution of the powder can be made substantially the same immediately after the start of the crushing operation of the crusher. Further, not only during the crushing operation of the crusher, but also when the crushing operation of the crusher is stopped, it is possible to control the supply of the object to be crushed to the crusher based on the output from the weight detector. By judging the stop of the crushing operation of the crusher based on the weight of the crushed object staying in the crusher, the crushing operation can be stopped before the weight of the crushed object staying in the crusher falls below a predetermined value. . Therefore, the particle size distribution of the powder at the end of pulverization by the pulverizer is less likely to change.

The rare earth alloy used as the object to be crushed as described in claim 4 is crushed and then solidified to be used for, for example, a magnet. When crushed by the above crushing method, Since the particle size distributions are almost the same, it is possible to obtain a homogeneous molded product. By producing the powder using the above-mentioned pulverization method, it is possible to obtain the powder having substantially the same particle size distribution, and the yield in the pressing step is improved. Therefore, if a sintered body is manufactured using such powder as described in claim 5, the yield of the sintered body can be improved.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. First, referring to FIG.
The overall configuration of the crushing device 10 according to the embodiment of the present invention will be described. The crushing device 10 is obtained by crushing the crushed material with the raw material charging machine 12 for supplying the crushed material, the crusher 14 for crushing the crushed material charged from the raw material charging machine 12. Classifier 16 for classifying powder, and classifier 16
And a recovery tank 18 for recovering the powder having a predetermined particle size distribution classified by.

The raw material charging machine 12 includes a raw material tank 20 for containing the material to be ground, a motor 22 for controlling the supply amount of the material to be ground from the raw material tank 20, and a spiral feeder 24 connected to the motor 22. Including and Crusher 14
Includes a vertically elongated substantially cylindrical crusher body 26. In the lower part of the crusher main body 26, a plurality of nozzle openings 28 for attaching a nozzle 88 (described later) for ejecting an inert gas at a high speed.
Is formed on the side of the crusher body 26.
A raw material input pipe 30 for inputting the material to be crushed is formed in the container 6. The raw material feeding pipe 30 is provided with a valve 32 for temporarily holding the material to be crushed and for confining the pressure inside the crusher 14. The valve 32 includes a pair of upper valve 32a and lower valve 32b. The feeder 24 and the raw material feeding pipe 30 are connected by a flexible pipe 34.

The crusher 14 includes a classification rotor 36 provided inside the crusher main body 26 and a motor 3 provided outside the crusher main body 26 and driving the classification rotor 36.
8 and a connection pipe 40 provided above the crusher main body 26 for discharging the powder classified by the classification rotor 36 to the outside.
including. The crusher 14 includes a plurality of legs 42 serving as a supporting portion, and a base 44 is arranged near the outer periphery of the crusher 14.
The crusher 14 is mounted on the base 44 by the legs 42. At this time, a weight detector 46 such as a load cell is provided between the leg 42 of the crusher 14 and the base 44.

The control unit 48 controls the number of revolutions of the motor 22 based on the output from the weight detector 46 to control the input amount of the material to be crushed. As shown in FIG. 2, the control unit 48 includes a plurality of A / D converters 50 for A / D converting the outputs from the three weight detectors 46, respectively.
The outputs from the D converter 50 are added by the adder 52 and given to the CPU 54 as weight data. The CPU 54 has a ROM 56 for storing a program for controlling the operation of the raw material feeder 12 and data such as the weight of the crusher 14,
A RAM 58 for storing set values and calculation data, and an input unit 60 including a control panel for inputting set values and the like are connected. The CPU 54 calculates the weight of the object to be crushed that remains in the crusher 14 based on the weight data, and calculates the proportional integral derivative (hereinafter, “PI
The calculation "D") is performed, and the PID deviation output obtained as a result is given to the inverter 62 as an analog output. The inverter 62 converts the analog output into a rotational speed, which is supplied to the motor 22 to control the motor 22. The set value may be stored in the ROM 56 in advance.

Returning to FIG. 1, the classifier 16 is the main body 6 of the classifier.
Including 4. An exhaust pipe 66 is provided inside the classifier body 64.
Is inserted from above. An introduction port 68 for introducing the powder classified by the classification rotor 36 is provided on the side of the classifier body 64, and the introduction port 68 is connected to the connection pipe 40 by a flexible pipe 70. An outlet 72 is provided in the lower portion of the classifier body 64, and the recovery tank 18 is connected to the outlet 72.

In such a crushing device 10, the crusher 14
The raw material tank 20, the motor 22, and the feeder 24 of the raw material feeding machine 12 are connected via a flexible pipe 34. The crusher 14 and the classifier 16 are connected via a flexible pipe 70. Therefore, the crusher 1
In addition to the crusher main body 26, the raw material feeding pipe 30, the connection pipe 40, the classification rotor 36, the motor 3 are provided on the leg portion 42 of the motor 4.
8 and the weight of the object to be crushed accumulated in the crusher 14 is added. The flexible pipes 34, 70
May be made of resin, rubber, or the like, or may be made flexible by forming a highly rigid material in a bellows shape or a coil shape, and is connected to one end thereof. It is sufficient that the member that can be easily displaced according to the change in the additional weight and that the change in the additional weight of the member connected to one end is difficult to be transmitted to the member connected to the other end.

In this way, the leg portion 42 of the crusher 14 has
The raw material tank 20 and the feeder 24, the weight of which changes depending on the amount of the crushed object, the classifier body 64, and the recovery tank
The change in the weight is hardly added through the flexible pipes 34 and 70. Therefore, if the weight is detected by the weight detector 46 provided on the leg portion 42, the crusher 1
It is possible to accurately detect the weight of the object to be ground and the amount of change in the object to be ground, and to accurately control the amount of the object to be ground to be fed into the crusher 14.

By providing the flexible pipe 34 closer to the feeder 24 than the valve 32 as in the above embodiment, the powder in the crusher 14 does not collide with the flexible pipe 34, and the flexible pipe 34 is made of powder. Will not wear. Therefore, since it is not necessary to strictly consider wear resistance and durability due to the collision of powder, the material and the structure which can be selected as the flexible pipe 34 are less restricted. Further, even when the inside of the crusher 14 is crushed in a depressurized state or a pressurized state, or when an inert gas is used, it is not necessary to strictly consider pressure resistance, corrosion resistance, etc., so the flexible pipe 34 is selected. There are less restrictions on the materials and configurations that can be made. The flexible pipe 34 may be provided closer to the crusher 14 than the valve 32. At this time, the weight of the valve 32 can be prevented from affecting the weight detector 46, so that the weight change of the crushed object can be detected more accurately.

Next, the arrangement of the main components of the crusher 14 will be described with reference to FIGS. 3 and 4. The motor 38 that drives the classification rotor 36 has a drive shaft 74 that drives the classification rotor 3
The pulley 7 is not coaxially connected to the rotating shaft 76 of the pulley 7.
8, through the belt 80 and the pulley 82, the motor 38
Is transmitted to the rotary shaft 76. With this configuration, the motor 38 can be arranged along the side portion of the crusher body 26. That is, in this case
Compared to the case where the drive shaft 74 is directly connected to the rotation shaft 76 of the classification rotor 36, the gravitational force of the motor 38 causes the crusher body 2 to move.
The rotation moment generated in 6 can be reduced.
Further, the raw material feeding pipe 30 is provided on a side portion opposite to the side portion of the crusher main body 26 in which the motor 38 is installed.

Further, at the lower part of the crusher main body 26, a take-out lid 84 for maintenance for removing the residual powder and the like inside the crusher 14 is provided. At this time, the hinge portion 86 of the take-out lid 84 has the crusher body 26 in which the motor 38 is installed.
Is provided on the side opposite to the side. Therefore, the rotation moment generated in the crusher body 26 by the motor 38, the rotation moment generated in the crusher body 26 by the raw material feeding pipe 30, and the crusher body 26 by the hinge portion 86.
It is possible to offset the rotational moment generated in the crusher, prevent the crusher main body 26 from tilting, and position the center of gravity of the crusher 14 at the center of the crusher 14. As a result, the load on the legs 42 can be evenly distributed, and the detection accuracy of the weight detector 46 can be improved.

The crusher main body 2 having the motor 38 installed
The side portion of 6 and the side portion of the opposite side do not necessarily need to be on the same straight line where the respective load points pass through the center of gravity of the crusher 14. The raw material feeding pipe 30 may be at a position where at least half or more of the rotational moment component generated by the raw material feeding pipe 30 cancels out the rotational moment generated by the motor 38. Hinge part 8
6 may be at a position where at least half or more of the rotational moment generated by the hinge portion 86 cancels out the rotational moment generated by the motor 38.

Further, in this embodiment, the take-out lid 84 is provided in the lower portion of the crusher main body 26, but when it is arranged at the side of the crusher main body 26, the take-out lid 84 is provided with the motor 38. It may be provided on a side portion opposite to the side portion of the crusher main body 26, and the condition of the installation position is the same as the above case. Instead of the pulleys 78, 82 and the belt 80, another transmission member such as a gear may be used.

Next, the leg portion 42 will be described. Figure 3
As can be seen clearly, three legs 42 are arranged at equal intervals on the outer circumference of the crusher body 26. The weight detector 46 is 3
It is provided on the lower surface of each of the two legs 42, and thus three are arranged at equal intervals. Thus three legs 4
2 supports the crusher body 26, and each leg 42
By providing the weight detectors 46 in each of the weight detectors 46 and adding the outputs of the respective weight detectors 46, even if the weight of the crusher 14 is tilted or deviated, the weight detectors The detection accuracy can be improved. Therefore, the object to be crushed can be accurately supplied. In particular, if the three legs 42 are used as the supporting portion, no floating occurs between the legs 42 and the base 44, the crusher 14 can be supported more stably without rattling, and the crushed object remains. The weight of the crusher 14 can be detected more accurately. In addition, although the case where three legs 42 are provided has been described in this embodiment, more legs may be provided.

As shown in FIG. 4, each leg portion 42 is provided on the side portion of the crusher main body 26 above the connection portion of the raw material feeding pipe 30. By arranging the leg portion 42 above the connecting portion of the raw material feeding pipe 30 in this manner, the weight of the raw material feeding machine 12 side added to the connecting portion can be added to a lower position of the crusher main body 26. The center of gravity of the crusher 14 can be set at a low position. Therefore, the crusher 14
The inclination of the crusher 14 due to the influence of the weight of the crusher 14 can be reduced, the crusher 14 can be stably supported, and the weight of the crusher 14 can be accurately detected. Thus, in order to reduce the inclination of the crusher 14 due to the influence of the weight of the crusher 14 or the like, it is preferable to provide the leg portion 42 at a position higher than the center of gravity of the crusher 14, and particularly, the classification rotor 36 is crushed. This is effective when it is provided above the inside of the machine body 26. Further, it is effective to position each leg portion 42 between the motor 38 having a large weight load and the connection portion of the raw material feeding pipe 30.

Further, by installing each leg portion 42 on a base 44 arranged near the outer periphery of the crusher main body 26, the base 4
It is possible to secure a sufficient distance between the installation location of the leg portion 42 and the crusher main body 26 with respect to 4. Therefore, the stability of the support of the crusher main body 26 can be enhanced, and the detection accuracy of the weight detector 46 can be improved. Also,
As shown in FIG. 4, a nozzle 88 is installed at each nozzle port 28. Each nozzle 88 is connected to a pipe 92 which supplies an inert gas, through a flexible pipe 90.

An outline of the crushing method by the crushing device 10 will be described with reference to FIG. First, the material to be crushed is put into the raw material tank 20. The material to be crushed in the raw material tank 20 is supplied by the supply device 24. At this time, the supply amount can be changed by controlling the rotation speed of the motor 22. The material to be crushed supplied from the feeder 24 is once blocked by the valve 32. Here, the pair of upper valve 32a and lower 32b are alternately opened and closed. That is, when the upper valve 32a is open, the lower valve 32b is closed, and when the upper valve 32a is closed, the lower valve 32b is open. In this way, a pair of valves 32
By alternately opening and closing a and 32b, the pressure in the crusher 14 is prevented from leaking to the raw material charging machine 12 side. Therefore, when the upper valve 32a is opened,
It is supplied between a pair of upper valve 32a and lower valve 32b, and when the lower valve 32b is opened next, it is guided to the raw material feeding pipe 30 and introduced into the crusher 14. The valve 32 is driven at high speed by a sequence circuit (not shown) different from the control circuit 48, and the material to be crushed is continuously supplied into the crusher 14.

The material to be crushed introduced into the crusher 14 is deposited on the lower part of the crusher 14, but is wound up in the crusher 14 by the injection of the inert gas from the nozzle port 28.
The objects to be crushed are crushed by mutual collision. The powder obtained by crushing the object to be crushed in this way is guided by the ascending air current to the classifying rotor 36, classified by the classifying rotor 36, and the coarse powder is crushed again. On the other hand, the powder pulverized to a predetermined particle size or less is passed through the connection pipe 40 and the flexible pipe 70 from the introduction port 68 to the classifier body 64.
It is introduced into the inside and accumulated in the recovery tank 18 installed in the lower part. Note that the too fine powder is led out to the outside from the exhaust pipe 66.

Next, the control method of the control unit 48 will be described with reference to FIG. First, the ROM 5 of the control unit 48
6 or the RAM 58 stores three set values in advance. The set value A is a set value that defines the initial charge amount, the set value B is a target set value during crushing, and the set value C is a set value for ending the operation of the crusher 14. Set value B
Corresponds to the first set value in the claims. Here, the set value A is larger than the set value B, and the set value C is smaller than the set value B (A>B> C). A plurality of deviation areas are set in advance with reference to the set value B. The control unit 48 periodically checks the weight detector 46.
In the case of this embodiment, the weight of the object to be crushed accumulated in the crusher 14 is calculated based on the total of the three weight data. Hereinafter, the “detection value” refers to the weight of the object to be crushed accumulated in the crusher 14.

The initial loading of the material to be crushed into the crusher 14 is carried out until the detected value reaches the set value A. Step S5
As long as it is determined in step S7 that the initial injection is performed, step S1 is performed until it is determined that the detected value has reached the set value A in step S7.
The weight detection of the crusher 14 in step S3 and the input of the crushed object in step S3 are continued. When it is detected in step S7 that the detected value has reached the set value A, in step S9 the feeding of the crushed object is interrupted, and in step S11 crushing of the crushed object is started. At the time of crushing, the inert gas is jetted at a high speed from the nozzle 88 and the classification rotor 36
Is rotated.

The end of crushing is determined by whether or not the detected value has reached the set value C (step S13). Step S5
If it is determined that it is not the initial charging in step S13, it is determined in step S13 whether or not the detected value has reached the set value C. If it has, the crushing is stopped in step S15. In this way, when the detected value reaches the set value C, it is determined that there is no more crushed material to be charged. In this case, the set value C is not set to a state where there is no object to be crushed in the crusher 14, that is, is set to zero, and even if the object to be crushed remains in the crusher 14, a predetermined value for the powder is determined. It is desirable to set the weight when the object to be pulverized is reduced to the state where the particle size distribution cannot be obtained. In other words, the set value C is preferably set slightly smaller than the set value B as described in the embodiment in which the result shown in FIG. 6 was obtained. When the same raw material is continuously pulverized, the remaining pulverized material is pulverized by newly supplying the raw material while maintaining the atmosphere in the pulverizer 14. When the raw material to be ground next is changed, the material to be ground is discharged.

In the normal crushing process, step S1
At 7, the PID calculation is performed based on the set value B, the detected value of this time, and the detected value of the previous time, and the injection amount change command is output. Here, in the PID calculation, the deviation between the current detected value and the set value is compared with the deviation between the previous detected value and the set value, and based on the direction and magnitude of the deviation between the respective deviations. Input amount is determined.

In this way, the input amount of the material to be crushed is controlled based on the weight detection. According to the crushing device 10, since the weight of the crushed object staying in the crusher 14 is detected by detecting the weight of the crusher 14 in which the crushed object stays, the crushed object stayed in the crusher 14 is detected. It is possible to detect the increase and decrease of an object without causing a time delay. Therefore, as compared with, for example, the case where the weight of the recovery tank 18 for recovering the powder discharged from the crusher 14 is measured, the supply amount of the crushed object to the crusher 14 can be appropriately increased or decreased without time delay.
As a result, hunting due to overshoot can be eliminated and the amount of the object to be ground in the grinder 14 can be kept constant. Further, by detecting the weight, the weight deviation from the target set value can be detected. Therefore, the supply amount can be increased or decreased according to the deviation, and the amount of the object to be ground in the grinder 14 can be brought closer to a desired value more quickly. As a result, the particle size distribution of the recovered powder can be made substantially the same, and the powder having a desired particle size distribution can be obtained.

Further, by controlling the supply amount of the pulverized material by PID control, it is possible to bring the amount of the pulverized material in the crusher 14 closer to a desired value and reduce the fluctuation.
Therefore, the particle size of the powder can be maintained within a certain range. Further, by determining the supply amount of the crushed object based on the current deviation and the previous deviation, the crushed object is supplied so that the amount of the crushed object in the crusher 14 approaches the desired value quickly. In addition, it is possible to prevent the amount of the pulverized material in the pulverizer 14 from greatly increasing and decreasing, and to make the particle size distribution of the powder substantially the same. Further, not only during the crushing operation of the crusher 14 but also during the supply of the crushed object before the crushing operation of the crusher 14 is started, the crushed object to the crusher 14 is output based on the output from the weight detector 46. Can control the supply of. Further, by setting the supply amount of the crushed object before the start of the crushing operation of the crusher 14 to be larger than the weight of the crushed object retained in the crusher 14 during the crushing, the crushed object is retained immediately after the start of the operation. The material to be crushed is reduced at a stretch, but the reduced amount can be supplemented in advance. Therefore, the particle size distribution of the powder can be made substantially the same immediately after the start of the crushing operation of the crusher 14 and thereafter.

Further, not only during the crushing operation of the crusher 14 but also during the crushing operation of the crusher 14 is stopped, the supply of the object to be crushed to the crusher 14 is controlled based on the output from the weight detector 46. can do. Further, by determining the stop of the crushing operation of the crusher 14 based on the weight of the crushed object accumulated in the crusher 14, before the weight of the crushed object in the crusher 14 becomes less than or equal to a predetermined value. The crushing operation can be stopped.
Therefore, the particle size distribution of the powder at the end of crushing by the crusher 14 does not change significantly.

Next, the change in the amount of residence of the crushed material and the change in the particle size for each lot will be described. The results shown in FIGS. 6 to 9 were obtained under the following grinding conditions. In the comparative example, the retention amount is 31 kg for the lower limit and 34 kg for the upper limit.
The crushing was performed by on / off control. In the embodiment, the initial charging amount is 40 kg and the crushing retention amount is 32.
PID control was performed with 5 kg and the crushing end amount of 31 kg. In both the comparative example and the embodiment, the crushing pressure was 0.
The pressure was 49 MPa, the number of revolutions of the classification rotor was 2000 rpm, and the average supply rate of the raw material was 50 kg / h.

As the material to be crushed, a powder of a rare earth alloy which is solidified after crushing and used for a magnet or the like was used. The rare earth alloy powder used as the object to be crushed was prepared as follows. First, US Pat. No. 5,383,
Slabs were made using the strip casting method as shown in 978. Specifically, Nd: 30 wt%,
B: 1.0 wt%, Dy: 1.2 wt%, Al: 0.2
An alloy having a composition of wt%, Co: 0.9 wt%, the balance Fe and unavoidable impurities was melted by high frequency melting. After this molten metal was maintained at 1350 ° C, it was rapidly cooled on a single roll under the conditions of a roll peripheral speed of about 1 m / sec, a cooling rate of 500 ° C / sec, and a supercooling degree of 200 ° C, and a thickness of 0.3.
A flaky alloy ingot having a size of mm and a size of 1 mm to 10 mm was obtained. Next, the alloy ingot roughly crushed by the hydrogen storage method to an average particle size of 1 mm or less was used as a crushed object.

FIG. 6 shows the retention amount of the rare earth alloy powder in the crusher 14 in the crusher 10 according to this embodiment.
FIG. 7 shows a comparative example, in which the weight of the crusher 14 is detected by the weight detector 46, the crusher 14 is controlled to be turned on / off, and the operation is performed from the start of powder feeding until the powder is removed from the crusher 14. The case is shown. The other conditions were the same. 6 and 7, the horizontal axis represents the elapsed time, and the vertical axis represents the retention amount of the rare earth alloy powder in the crusher 14. In the comparative example, as shown in FIG. 7, at the time of initial charging, even after a predetermined amount of powder has been charged, and after a predetermined amount of powder has accumulated, the retention amount is the standard retention amount (32 in this embodiment). It can be seen that there is always a large increase and decrease repeatedly before and after 0.5 kg). On the other hand, as shown in FIG. 6, in this embodiment, it is found that the fluctuation range of the retention amount is reduced not only at the beginning of operation but also during operation.

FIG. 8 is a diagram showing the variation of grain size by lot according to this embodiment, and FIG. 9 is a diagram showing the variation of grain size by lot according to the comparative example corresponding to FIG. 8 and 9 show the 50% particle size in the integrated particle size distribution,
The variation of 99% particle size by lot is shown. The number of sample lots is 100 in this embodiment and the comparative example. Here, the particle size was measured using a laser diffraction type particle size distribution measuring device (HELOS type) sold by Japan Laser Co., Ltd. An example of the particle size distribution is shown in FIG.
It shows in 0. As is clear from FIGS. 8 and 9, it can be seen that the variation in particle size for each lot is smaller in this embodiment than in the comparative example. In particular, the fluctuation range of the particle size at the 99% particle size is small. Therefore, it can be seen that the particle size distribution of the powder is almost the same in this embodiment as compared with the comparative example.

As described above, according to this embodiment, since it is possible to obtain a rare earth alloy having substantially the same particle size distribution, it is possible to reduce the occurrence of press cracks in the pressing step and obtain a homogeneous compact. it can. in this way,
It is possible to obtain a powder having substantially the same particle size distribution and improve the yield in the pressing step. Therefore, if a sintered body is manufactured using such a powder, the yield of the sintered body can be improved.

To obtain a sintered body from powder, first, the powder is oriented in a magnetic field of 0.8 MA / m and molded under a pressure of 14.7 MPa. Then, the obtained molded body is sintered in an argon atmosphere at 1000 ° C to 1200 ° C for about 1 hour and then cooled to obtain a sintered body. The set values A, B, and C may be set as values including the weight of the crusher 14, respectively, and the operation of charging the crushed object may be performed. Further, the motor 38 may be arranged along the upper portion of the crusher body 26.

[0050]

According to the present invention, the supply amount can be increased or decreased according to the deviation, and the amount of the object to be crushed in the crusher can be brought closer to the desired value more quickly. As a result, the particle size distribution of the recovered powder can be made almost the same,
It is possible to obtain a powder having a desired particle size distribution. Further, if a sintered body is manufactured using such a powder, the yield of the sintered body can be improved.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a crushing device according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a control unit used in the crushing apparatus according to this embodiment.

FIG. 3 is a plan view showing a main configuration of a crusher used in the crushing apparatus according to this embodiment.

FIG. 4 is a sectional view taken along line III-III in FIG.

FIG. 5 is a flowchart showing an example of main operations of the crushing device according to this embodiment.

FIG. 6 is a graph showing a retention amount of a material to be ground in a grinding machine in a grinding apparatus according to this embodiment.

FIG. 7 is a graph showing a retention amount of an object to be ground in a grinder in a grinder according to a comparative example.

FIG. 8 is a diagram showing variation in particle size by lot according to this embodiment.

FIG. 9 is a diagram showing variations in particle size by lot according to a comparative example.

FIG. 10 is a diagram showing an example of a particle size distribution.

[Explanation of symbols]

10 crusher 12 Raw material feeder 14 crusher 16 classifier 18 Recovery tank 26 Crusher body 34, 70 Flexible pipe 36 classification rotor 42 legs 46 Weight detector 48 control unit

─────────────────────────────────────────────────── ─── Continuation of front page (56) References JP-A-10-85620 (JP, A) JP-A-9-29117 (JP, A) JP-A-8-148317 (JP, A) Actual development Sho-62- 164943 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) B02C 23/02 B02C 25/00

Claims (5)

(57) [Claims] 1. A crusher for crushing a rare earth alloy, a raw material feeder for supplying the rare earth alloy to the crusher, a recovery tank for recovering the powder obtained by the crusher, and the crushing in which the rare earth alloy is retained A weight detector for detecting the weight of the machine, a first flap provided between the raw material feeder and the crusher.
Reflexible pipe, second flap provided between the crusher and the recovery tank
A control unit that controls the supply amount of the rare earth alloy to the crusher by proportional-plus-integral-derivative control so that the rare earth alloy in the crusher has a constant amount based on the output from the lexible pipe and the weight detector. The crusher includes a crusher body and a side portion of the crusher body.
Includes a raw material charging pipe being formed, and three supporting portions that are provided at equal intervals on the outer circumference of the crusher main body, the material projection
The inlet pipe is connected to the original through the first flexible pipe.
Is connected to a raw material feeding machine, and each of the supporting portions is connected to the raw material feeding pie.
The crusher body at a position above the connecting portion between the press and the crusher body and above the center of gravity of the crusher.
And the weight detector includes a detector provided on each of the supporting portions. 2. The crushing device according to claim 1, wherein the crusher further includes a classification rotor provided above the inside of the crusher body and classifying the powder. 3. A crushing method using a crusher for crushing the supplied crushed object and discharging the obtained powder to the outside, wherein the weight of the crushed object retained in the crusher during crushing. And a second corresponding to a weight greater than the weight of the crushed object corresponding to the first set value.
A set value and a third set value corresponding to a weight smaller than the weight of the crushed object corresponding to the first set value are set, and the weight of the crusher in which the crushed object stays is detected by a weight detector. detected by step, the <br/> said to the crusher before the start of the grinding operation of the grinding machine during the supply of the pulverized material, on the basis of the output and the second set value from the weight detector A step of controlling the supply operation of the crushed object to the crusher; during a crushing operation of the crusher, a deviation is calculated based on the output from the weight detector and the first set value, A step of determining a supply amount of the object to be ground to the grinder based on a deviation and a previous deviation, and a grinding operation of the grinder based on an output from the weight detector and the third set value Crushing with steps to control the stopping of Law. 4. The crushing method according to claim 3, wherein the object to be crushed is a rare earth alloy. 5. A sintered body produced by using the powder obtained by the pulverization method according to claim 3.