JP2006122925A - Powder feeder for powder molding press - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To feed a fixed amount of powder to a die of a powder molding press in a short period of time. <P>SOLUTION: A powder box 20 has a powder volume exceeding the amount of powder required for single molding. Thus, in a position P2 just above the cavity 26 of a die 24, even after the charge of the powder to the cavity 26, a state where the powder is left in the powder box 20 comes out. But, the remaining amount of the powder in the powder box 20 is affected by the leakage of the powder, or the like and is not fixed, the amount of the powder remaining in a subhopper 16 after the blowing-off of the powder to the powder box 20 is varied. The amount of the remaining powder in the subhopper 16 is detected by a powder amount detection sensor 22, and a powder weighing machine 14 is controlled in such a manner that, based on the detected result, the amount of the powder regulated based on the amount of the powder required for single molding is cut out. In this way, the amount of the powder in the powder box 20 is made stable, and the amount of the powder charged from the powder box 20 to the cavity 26 is made stable as well. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a powder feeding apparatus that supplies a certain amount of powder to a mold of a powder molding press.

  The powder feeding device of the powder molding press includes a powder box for temporarily storing powder supplied from a powder supply source, and slides the powder box from the powder receiving position to the powder discharging position on the mold cavity. In general, the apparatus configuration is such that the powder in the powder box is put into the cavity of the mold. The most widely used powder feeder has hitherto had a structure in which powder is dropped from above the press mold through a hose into a powder box. However, the powder feeding apparatus having such a structure has a problem that the amount of powder supplied to the powder box is likely to fluctuate and greatly affects the product weight. In order to solve such a problem, a powder feeding device has been invented that intermittently weighs the powder for the target value of the product weight for each molding and supplies it to the powder box (for example, Patent Document 1). .) Moreover, the powder feeder which supplies a fixed quantity of powder into a powder box for every shaping | molding from the raw material hopper using a flexible feeder or a spiral feeder is also invented (for example, refer patent document 2).

JP-A-11-104895 ([0040] to [0058], FIGS. 1 to 10) JP 2001-62593 A ([0015] to [0025], FIGS. 1 to 6)

However, in the case of a conventional powder feeder that intermittently weighs the target amount of powder for each molding, if there is a thin part in the cavity, it takes time to input the powder, The product is affected by powder leakage from the powder box when sliding the box from the powder receiving position to the powder discharging position on the mold cavity, and powder leakage from the gap between the die and the punch of the mold. The problem is that the variation in weight cannot be suppressed. Increasing the powder input time will lead to a decrease in productivity and an increase in product cost, and fluctuations in product weight will cause product dimensional defects and density defects. Both product quality and product cost were problematic.
In addition, the powder feeder using a flexible feeder or spiral feeder shortens the time required for charging the powder, but the accuracy of the amount of powder supplied to the powder box depends on the accuracy of these feeders. Therefore, it is necessary to control the operation of the powder feeding device with high accuracy, and the configuration of the powder feeding device is complicated. In addition, problems related to powder leakage were not solved. Since the amount of powder leakage is not constant from time to time, even if a large amount of powder is supplied to the powder box in anticipation of the amount of powder leakage in these conventional powder feeders, the mold cavity It did not lead to stabilizing the amount of powder supplied to the tea.
The present invention has been made in view of the above problems, and the object of the present invention is to provide a fixed amount of powder molding press with respect to the mold of the powder molding press without complicated control. This is because the powder can be supplied in a short time.

  In order to solve the above problems, a powder feeding device of a powder molding press according to the present invention includes a raw material powder hopper, a powder weighing machine, a sub hopper having a powder volume exceeding the amount of powder required for one molding, A shutter that opens and closes the powder outlet of the sub hopper, and a powder box having a powder volume exceeding the powder amount required for one molding are arranged in this order, and the powder amount detection sensor of the sub hopper, Based on the amount of powder required for one molding based on the detection means of the drive means for moving the powder box between the position directly below the shutter and the position directly above the mold cavity, and the powder amount detection sensor And a control means for controlling the powder weighing machine so as to cut out the adjusted amount of powder.

According to the present invention, the powder in the raw material powder hopper is weighed by the powder weighing machine, and the necessary amount of powder is cut out to the sub hopper. When the powder box is at a position directly below the shutter, the shutter is opened to discharge the weighed powder from the sub hopper to the powder box. Then, the powder in the powder box can be filled into the mold cavity by moving the powder box from the position immediately below the shutter to the position directly above the mold cavity by the driving means.
Here, since the powder box according to the present invention has a powder volume exceeding the amount of powder necessary for one molding, the powder remains in the powder box after one molding. The remaining amount of powder is not constant due to the influence of powder leakage and the like. Also, when the powder is discharged from the sub hopper to the powder box due to natural fall when the shutter is opened and the amount of powder in the powder box exceeds a certain level, the powder accumulated in the powder box itself will be the powder outlet of the sub hopper. The flow of powder from the sub hopper to the powder box is physically stopped, but the amount of powder remaining in the sub hopper at that time also varies. Therefore, the amount of powder remaining in the sub hopper is detected by a powder amount detection sensor, and based on the detection result, the control unit cuts out the amount of powder adjusted based on the amount of powder necessary for one molding. And controlling the powder weighing machine.

  Specifically, when it is detected by the powder amount detection sensor that the residual powder amount of the sub-hopper is below a predetermined minimum powder amount, the amount of powder that exceeds the amount of powder necessary for one molding by the control means Command the weigher to cut out On the other hand, when it is detected by the powder amount detection sensor that the residual powder amount of the sub hopper exceeds the predetermined maximum powder amount, the control unit cuts out the powder amount below the powder amount necessary for one molding. Instruct the weighing machine to On the other hand, when the powder amount detection sensor detects that the residual powder amount of the sub hopper is an appropriate powder amount, the weighing unit is configured to cut out the predetermined powder amount required for one molding by the control means. Command.

Therefore, an appropriate amount of powder is always supplied from the weighing machine to the sub hopper from time to time, and as a result, the amount of powder in the powder box receiving the powder supply from the sub hopper is stabilized. Therefore, the amount of powder filled from the powder box into the mold cavity is also stabilized. In addition, since the powder exceeding the amount of powder required for one molding is supplied to the powder box, even if powder leakage occurs, the amount of powder filled into the mold cavity is insufficient. There is nothing.
In addition, it is possible to cut the powder from the raw material powder hopper to the sub hopper for the next molding cycle between the time of supplying the powder to the mold related to the previous cycle and after the completion of the powder molding. It is. Also, after returning the powder box from the position directly above the mold cavity to the position directly below the shutter by the driving means, the weighing is performed for the next molding cycle from the sub hopper to the powder box by opening the shutter. The discharged powder can be discharged immediately, and the powder can be charged into the powder box in a very short time.

In the present invention, the powder weighing machine opens and closes a vibratory feeder or weighing shutter, a temporary powder storage container, a weight measurement sensor for the temporary powder storage container, and a powder outlet of the temporary powder storage container. It is desirable to provide a shutter that performs.
According to the present invention, when the powder in the raw material powder hopper is sent to the powder temporary storage container by the vibratory feeder or the weighing shutter, the weight of the powder temporary storage container is measured by the weight measuring sensor, thereby temporarily storing the powder. The amount of powder in the container can be accurately grasped. And when the amount of powder in the temporary storage container becomes the required amount, it is necessary to temporarily stop the vibratory feeder or close the weighing shutter and open the shutter to open and close the powder outlet of the temporary powder storage container. An amount of powder can be cut into a sub-hopper. Therefore, an appropriate amount of powder is supplied from the weighing machine to the sub hopper, and as a result, the amount of powder in the powder box receiving the powder supply from the sub hopper is stabilized.

  Since the present invention is configured as described above, it is possible to supply a fixed amount of powder to the mold of the powder molding press in a short time without complicated control in the powder feeding device of the powder molding press. It becomes.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
The powder feeding apparatus 10 of the powder molding press according to the embodiment of the present invention includes a raw material powder hopper 12, a powder weighing machine 14, a sub hopper 16 having a powder volume exceeding the amount of powder necessary for one molding, A shutter 18 for opening and closing the powder outlet of the sub hopper 16 and a powder box 20 having a powder volume exceeding the amount of powder required for one molding are arranged in this order.
Further, the sub hopper 16 is driven to move the powder amount detection sensor 22 in the sub hopper and the powder box 20 between a position P1 directly below the shutter 18 and a position P2 directly above the cavity 26 of the mold 24. Means 28 and control means 30 for controlling the powder weighing machine 14 so as to cut out the amount of powder adjusted on the basis of the amount of powder necessary for one molding based on the detection result of the powder amount detection sensor 22. I have.

Each structure of the powder supply apparatus 10 of the powder molding press will be further described.
First, the powder weighing machine 14 includes a vibratory feeder 32, a funnel-shaped temporary storage container 34, a weight measurement sensor 36 of the temporary storage container 34, and a shutter 38 that opens and closes the powder outlet of the temporary storage container 34. I have. The shutter 38 is driven to open and close by a driving means such as a cylinder. Note that a weighing shutter may be used instead of the vibratory feeder 32.
The sub hopper 16 has a funnel shape, and its powder outlet is disposed as close as possible to the upper surface of the powder box 20 while securing the installation space of the shutter 18. Therefore, when the amount of powder falling from the sub hopper 16 to the powder box 20 due to gravity drop exceeds a certain amount, the powder itself accumulated in the powder box 20 blocks the powder outlet of the sub hopper 16 and the flow of the powder is blocked. The movement of the powder from the sub hopper 16 to the powder box 20 is physically stopped. The shutter 18 is driven to open and close by a driving means such as a cylinder. Further, as described above, the opening time of the shutter 18 is set to a necessary and sufficient time so that the opening state is maintained until the movement of the powder from the sub hopper 16 to the powder box 20 is physically stopped. .

  The powder box 20 is open at the top and bottom, and is slidable on a flat slide table 40 continuous with the top surface of the die 24A. The box 20 slides on the slide table 40 by the expansion and contraction of the piston rod 28a of the cylinder constituting the driving means 28, and the powder in the box 20 is separated from the position P1 directly below the shutter 18 and the mold 24. It moves between the position P2 immediately above the cavity 26 as shown by the arrow S. In addition, it is further preferable to give a fine reciprocating motion to the piston rod 28a of the cylinder at the position P2 immediately above the cavity 26 so that the powder in the powder box 20 is filled into the cavity 26. Further, the box 20, the driving means 28, the slide table 40, the die 24A, the lower punch 24B, and the upper punch 24C of the mold 24 have the same configuration as that of an existing powder molding press and its powder feeding device.

  The powder amount detection sensor 22 in the sub hopper 16 includes a minimum powder amount detection sensor 22A that detects that the powder amount in the sub hopper 16 is equal to or less than the minimum amount in the range of the optimum powder amount, and the sub hopper 16 And a maximum powder amount detection sensor 22B that detects that the powder amount is equal to or greater than the maximum amount in the range of the optimum powder amount, and any detection result is grasped by the control means 30. . The control means 30 can be constituted by an electronic computer such as a personal computer and not only receives the detection signal of the sensor 22, but also receives the detection signal of the weight measurement sensor 36 of the powder weighing machine 14, and the powder. Determination of the amount of powder supplied to the sub hopper 16 by the weighing machine 14 and transmission / reception of control signals to the vibratory feeder 32 are performed.

Here, the powder supply procedure by the powder supply apparatus 10 of the powder molding press according to the embodiment of the present invention will be described.
First, as an overall flow, the powder in the raw material powder hopper 12 is weighed by the powder weighing machine 14, and a necessary amount of powder is cut out to the sub hopper 16. When the powder box 20 is at the position P1 directly below the shutter 18, the shutter 18 is opened and the weighed powder is dispensed from the sub hopper 16 to the powder box 20. Furthermore, the powder in the powder box 20 is transferred to the mold 24 by moving the powder box 20 from the position P1 directly below the shutter 18 to the position P2 directly above the cavity 26 of the mold 24 by the driving means 28. The cavity 26 is filled.

  By the way, since the powder box 20 has a powder volume exceeding the amount of powder necessary for one molding, the powder is filled into the cavity 26 at a position P2 immediately above the cavity 26 of the mold 24. Even after the molding is performed once, the powder remains in the powder box 20. However, the remaining amount of powder in the powder box 20 is not constant due to the influence of the powder leakage described above. Accordingly, when the powder is discharged from the sub hopper 16 to the powder box 20 by opening the shutter 18, as described above, when the flow of the powder from the sub hopper 16 to the powder box 20 is physically stopped, the sub hopper The amount of powder remaining in 16 also varies. Therefore, in the embodiment of the present invention, the amount of powder remaining in the sub hopper 16 is detected by the powder amount detection sensor 22, and based on the detection result, the control unit 30 calculates the amount of powder necessary for one molding. The powder weighing machine 14 is controlled so as to cut out the amount of powder adjusted to the reference.

  Specifically, when the minimum powder amount detection sensor 22A detects that the minimum powder amount is less than the minimum powder amount, the control unit 30 cuts out the powder amount exceeding the powder amount necessary for one molding. A command is given to the vibratory feeder 32. The amount of powder discharged from the vibratory feeder 32 to the temporary storage container 34 is measured by the weight measuring sensor 36 with the weight of the temporary storage container 34 together with the powder, and fed back to the control means 30. On the other hand, when the maximum powder amount detection sensor 22B detects that the maximum powder amount is exceeded, the control unit 30 uses the vibration type of the weighing machine 14 to cut out the powder amount that is less than the powder amount required for one molding. Commands the feeder 32. On the other hand, when the amount of powder in the sub hopper 16 is between the minimum amount of powder and the maximum amount of powder, the weighing means 14 cuts out the amount of powder necessary for one molding by the control means 30. A command is given to the vibratory feeder 32.

According to the embodiment of the present invention having the above-described configuration, an appropriate amount of powder is always supplied from the weighing machine 14 to the sub hopper 16 from time to time. The amount of powder in the powder box 20 that receives the powder supply is stabilized. Therefore, the amount of powder filled from the powder box 20 into the cavity 26 of the mold 24 is also stabilized. In addition, since the powder exceeding the amount of powder required for one molding is supplied to the powder box 20, even if powder leakage occurs, the amount of powder filled into the cavity 26 of the mold 24 There is no shortage.
Moreover, it is good also as setting the measurement target value of the powder weighing machine 14 and supplying the said setting amount for every shaping | molding so that the quantity of the powder to weigh may be larger than the quantity of the powder consumed by shaping | molding. In this case, after filling the powder box 20 from the sub hopper 16, when the amount of powder in the sub hopper 16 exceeds the maximum powder amount detection sensor 22 </ b> B, the powder weighing machine 14 (temporary storage container 34) transfers to the sub hopper 16. Stop supplying powder. Control is performed so that the powder is supplied from the weighing machine 14 (temporary storage container 34) to the sub hopper 16 only when the amount of powder in the sub hopper 16 falls between the maximum amount of powder and the minimum amount of powder. According to this control method, since it is not necessary to change the weighing target value of the powder weighing machine 14, powder supply can be performed by a simpler control procedure.
Further, according to the embodiment of the present invention, the operation of cutting the powder from the raw material powder hopper 12 to the sub hopper 16 for the next molding cycle is performed from the operation of supplying the powder to the mold according to the previous cycle. It is possible to carry out until after the powder molding is completed. Then, after the powder box 20 is returned from the position P2 immediately above the mold cavity to the position P1 directly below the shutter by the driving means 28, the shutter 18 is opened to move the powder box 20 from the sub hopper 16 to the powder box 20. The weighed powder for the next molding cycle can be immediately discharged, and the powder can be charged into the powder box 20 in a very short time.

Further, in the embodiment of the present invention, when the powder in the raw material powder hopper 12 is sent to the powder temporary storage container 34 by the vibratory feeder 32, the weight of the powder temporary storage container 34 is measured by the weight measuring sensor 36. By doing so, the amount of powder in the temporary storage container 34 can be accurately grasped. When the amount of powder in the temporary storage container 34 becomes a required amount, the vibratory feeder 32 is temporarily stopped, and the shutter 38 that opens and closes the powder outlet of the powder temporary storage container 34 is opened. Powder can be cut into the sub-hopper 16. Therefore, an appropriate amount of powder is supplied from the weighing machine 14 to the sub hopper 16, and as a result, as described above, the amount of powder in the powder box 20 that receives the powder supply from the sub hopper 16 is stabilized. It becomes.
As described above, according to the powder feeding apparatus 10 of the powder molding press according to the embodiment of the present invention, a difference occurs between the amount of powder consumed and the amount of powder charged in the powder box 20 due to disturbance such as powder leakage. Even in such a case, since the powder in the sub hopper 16 automatically adjusts the difference, the powder weighing machine 14 is required to have high-precision weighing capability without performing complicated control. Accordingly, a certain amount of powder can be supplied to the mold of the powder molding press in a short time.

It is the schematic which shows the powder supply apparatus of the powder molding press which concerns on embodiment of this invention.

Explanation of symbols

10: Powder feeding device of powder molding press, 12: Raw material powder hopper, 14: Powder weighing machine, 16: Sub hopper, 18: Shutter, 20: Powder box, 22: Powder amount detection sensor, 24: Mold, 26: Cavity, 28: Driving means, 30: Control means, 32: Vibrating feeder, 34: Temporary storage container, 36: Weight measuring sensor, 38: Shutter

Claims (2)

Raw material powder hopper, powder weigher, sub hopper having a powder volume exceeding the amount of powder required for one molding, shutter for opening and closing the powder outlet of the sub hopper, and amount of powder necessary for one molding Are arranged in this order with a powder box having a powder volume greater than
Based on the detection result of the powder amount detection sensor, the driving means for moving the powder box between the position immediately below the shutter and the position immediately above the cavity of the mold, and the detection result of the powder amount detection sensor. And a control means for controlling the powder weigher so as to cut out the amount of powder adjusted based on the amount of powder required for forming the powder. The powder weighing machine includes a vibratory feeder or weighing shutter, a powder temporary storage container, a weight measurement sensor for the powder temporary storage container, and a shutter for opening and closing the powder outlet of the powder temporary storage container. The powder feeding apparatus of the powder molding press according to claim 1.

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