JP4330104B2 - Control device for powder filling machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to, for example, a powder filling machine for quantitatively filling a powder into a packaging bag or packaging container by rotation of an auger screw installed in a funnel, and in particular, an excessive load on rotation of the auger screw. The present invention relates to a control device having a function of detecting the occurrence of the problem.
[0002]
[Prior art]
This type of auger screw type powder filling machine rotates an auger screw in the funnel (hereinafter simply referred to as “auger”) a predetermined number of times for each filling cycle, and then determines a certain amount of powder from the discharge port at the lower end of the funnel. The body is discharged and filled. More specifically, the auger has a spiral wing, and the wing is rotated in a funnel filled with the powder, so that the frictional resistance with the powder becomes very large. Although a motor with sufficient torque performance to overcome the frictional resistance of the granular material is used to drive the auger, if the auger is forced to rotate with too much load, so-called powder biting Phenomena occur, and in extreme cases, damage to the machine or crushing of the granular material is caused.
[0003]
For this reason, for example, Japanese Patent No. 2771181 discloses a technique for detecting that an excessive load is generated in the rotation of the auger. This known technique calculates the theoretical rotation time of the auger per filling cycle based on the operating conditions of the servo motor that drives the auger, while measuring the rotation duration time from when the auger actually starts to rotate. In addition, it is determined as an overload when the time difference between these exceeds a predetermined abnormality detection time.
[0004]
[Problems to be solved by the invention]
However, since the known technique described above makes an overload determination only after a predetermined abnormality detection time has elapsed after the theoretical rotation time of one filling cycle has elapsed, an excessive load has occurred during this period. However, it is impossible to detect this at all. Therefore, if the rotational load of the auger increases extremely during one filling cycle, the machine may be damaged or the granular material may be crushed before the overload is determined.
[0005]
Accordingly, the present invention has been made in view of the development of a technique that can immediately detect when an excessive load is generated in the rotation of the auger during one filling cycle.
[0006]
[Means for Solving the Problems]
The control apparatus for the granular material filling machine according to the present invention (Claim 1) outputs a command pulse to the servo motor for rotating the auger every predetermined control cycle, and the command rotation proportional to the number of output of the command pulse. The drive means that drives the servo motor by the number of times, the measurement means that measures the actual number of rotations of the servo motor for each control cycle, and outputs the result as a measurement pulse, and the number of command pulses output from the beginning of the filling cycle And detecting means for detecting a rotation overload of the auger based on the deviation.
[0007]
According to the control device described above, the deviation between the output number of command pulses and the output number of measurement pulses per filling cycle is obtained in real time for each control cycle as the auger rotates. This is because when the rotation load of the auger increases, the actual number of rotations is delayed relative to the number of command rotations, so there is a discrepancy between the number of command pulse outputs and the number of measurement pulse outputs. Based on what appears as a “stack pulse”. Therefore, if the rotation overload of the auger is detected based on this deviation, the rotation overload that occurs during one filling cycle can also be determined in real time.
[0008]
More practically, it is preferable that the control device of the present invention (Claim 2) further includes stop means for immediately stopping the drive of the servo motor when a rotation overload of the auger is detected. In this case, in the actual machine, breakage of the auger and its drive member, crushing of the granular material due to powder biting, and the like are prevented in advance, and subsequent recovery work is facilitated.
Moreover, the detection means mentioned above can memorize | store the preset threshold value, and the aspect which implement | achieves detection of rotation overload when the calculated | required deviation exceeds a threshold value is preferable. In this case, the magnitude of the rotational overload that is detected differs depending on the threshold setting, so the magnitude of the rotational overload that should be detected is appropriately adjusted according to the type of the filling machine and the properties of the powder to be handled. it can.
[0009]
In addition, if an input means that can change and input the threshold setting to the detection means is further provided (Claim 4), it is easier to adjust the rotational overload to be detected each time. Furthermore, if a display means for displaying numerically the deviation obtained by the detecting means is provided (Claim 5), it becomes easy to monitor the rotational load of the auger during operation of the powder filling machine.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is suitable for a control device of a powder filling machine for quantitatively filling a packaging container with, for example, roasted coffee beans for sale. However, the present invention is not limited to this application.
FIG. 1 shows a specific embodiment thereof. The powder filling apparatus includes a funnel 2 arranged vertically, and the funnel 2 includes a hopper 4 and a cylindrical portion 6 connected to the lower end of the hopper 4. The funnel 2 can be supplied with the powder particles from above through the hopper 4 and can store the powder particles in the cylindrical portion 6. An auger 8 extending vertically is rotatably disposed in the funnel 2, and the auger 8 has a spiral wing around the auger shaft 10. A circular drip 12 is attached to the lower end of the auger 8, and this drip 12 forms an annular discharge port 14 between the lower end of the cylindrical portion 6.
[0011]
The auger shaft 10 extends upward from the hopper 4 and is connected to the output shaft of the servo motor 16. When this servo motor 16 is driven, the auger 8 is rotated in one direction. Further, along with this rotation, an amount of granular material corresponding to the number of rotations of the auger 8 is discharged from the discharge port 14 of the funnel 2.
An agitator 18 is disposed in the hopper 4, and the agitator 18 is supported by a rotating sleeve 20 surrounding the auger shaft 10 via a stay. The rotation sleeve 20 is rotated by a motor (not shown), and the agitator 18 can be rotated in the direction opposite to the rotation direction of the auger 8 via the stay.
[0012]
Although not shown, for example, a belt conveyor is horizontally disposed below the funnel 2, and can containers for receiving powder particles are placed on the belt conveyor at predetermined intervals. Has been. The belt conveyor can position the can containers sequentially below the funnel 2 by the intermittent drive.
The servo motor 16 described above is connected to a controller 24 via a servo amplifier 22. The controller 24 includes a microcomputer having a central processing unit (CPU), a memory such as a ROM and a RAM, and an input / output interface. The controller 24 controls the rotation of the motor 16 via the servo amplifier 22. The servo motor 16 is equipped with an encoder 26, and a feedback pulse from the encoder 26 is sent to the controller 24 through the servo amplifier 22.
[0013]
The controller 24 is divided into several blocks according to its function, and specifically includes a command pulse output unit 28, a pool pulse calculation unit 30, and a rotation overload detection unit 32. The command pulse output unit 28 outputs a command pulse Pi every fixed control period (for example, 3 ms) based on a predetermined operation pattern in response to an operation signal input to the powder and particle filling machine. The command pulse Pi is output to the servo motor 16 through the servo amplifier 22, and the servo motor 16 is driven at the number of rotations proportional to the output number. At this time, the operation pattern is defined from the acceleration mode, the constant speed mode, and the deceleration mode of the auger 8, and in the acceleration mode, the number of output of the command pulse Pi per control cycle is increased according to the acceleration, and conversely the deceleration. Reduced in mode. In the constant speed mode, a fixed number of command pulses Pi are output. Further, the control cycle is not particularly limited, and can be shortened according to the arithmetic processing capability of the controller 24.
[0014]
The pulses output from the encoder 26 can be used to measure the actual number of rotations of the auger 8 for each control cycle described above. Therefore, the pool pulse calculation unit 30 determines the pulses output from the encoder 26. Received as measurement pulse Pe. On the other hand, the command pulse Pi described above is also output to the pool pulse calculation unit 30 at the same time. The accumulation pulse calculation unit 30 obtains a deviation between the output number of the command pulse Pi and the output number of the measurement pulse Pe accumulated from the beginning of one filling cycle, and outputs this deviation to the rotation overload detection unit 32 as the accumulation pulse Ps. To do.
[0015]
The rotation overload detector 32 detects an overload that occurs in the rotation of the auger 8 based on the accumulation pulse Ps. As a specific detection method, for example, a preset threshold value can be given to the overload detection unit 32. When the accumulated pulse Ps is input exceeding this threshold value, the overload detection unit 32 It is determined that an excessive load is generated in the rotation of the auger 8, and the detection of the overload is established. In this case, the overload detection unit 32 outputs an overload detection signal L to the command pulse output unit 28. The setting of the threshold used for detecting overload will be further described later.
[0016]
A touch panel 34 is connected to the controller 24 described above through an input / output interface. The touch panel 34 is installed at a position where an operator who operates the powder filling machine can operate nearby, and the operator can input and output various data through the operation screen. Specifically, the touch panel 34 includes an operation condition setting unit 36, a pool pulse display unit 38, and an overload determination value input unit 40. Of these, the operator can set the above-described operation pattern of the auger 8 as desired for the operation condition setting unit 36, and the set operation pattern is taught to the command pulse output unit 28 of the controller 24.
[0017]
The accumulation pulse Ps calculated by the accumulation pulse calculation section 30 of the controller 24 can be displayed on the accumulation pulse display section 38 (display means) of the touch panel 34. As this display means, for example, various modes such as digital numerical display and analog display which change in real time, and graph display including time change can be considered.
[0018]
The operator can set the above-described threshold value through the overload judgment value input unit 40 (input means). For example, the granule filling machine is operated in a steady state for each filling material, and the maximum value excluding the extremely different accumulation pulse Ps from the accumulation pulse Ps obtained at this time is used as the reference value. A value with some margin is set as the overload judgment value Pj. When starting the operation of the powder filling machine, the operator can input the overload judgment value Pj preset for each filling material through the overload judgment value input unit 40 of the touch panel 34.
[0019]
【Example】
The function of the control device of the present invention will be described below by giving specific examples.
FIG. 2 shows a control routine executed by a main control unit (not shown in particular) of the controller 24 as an embodiment, and this control routine is performed in parallel with the operation of the powder filling machine. It is executed once per cycle.
[0020]
First, in step S1 of the control routine, the presence or absence of an operation signal of the auger 8 is determined. Specifically, when an operation signal is input to the command pulse output unit 28 (Yes), the process proceeds to step S2. . Note that while there is no operation signal input, the control routine is simply returned in step S1.
In step S <b> 2, the controller 24 outputs a command pulse Pi from the command pulse output unit 28. At this time, the command pulse Pi is output according to the operation pattern set by the operator through the touch panel 34, and the operation pattern is given from the operation condition setting unit 36 to the command pulse output unit 28. When the servo motor 16 is driven in accordance with the output of the command pulse Pi, the auger 8 is actually rotated and filling of the granular material is started (driving means).
[0021]
In step S <b> 3, the controller 24 reads the measurement pulse Pe from the encoder 26 in the accumulation pulse calculation unit 30 as the servo motor 16 is driven (measurement unit). In step S4, the controller 24 calculates the value of the pool pulse Ps in real time at the pool pulse calculator 30.
In step S5, the controller 24 compares the value of the accumulation pulse Ps with the overload determination value Pj in the rotation overload detector 32. While the accumulation pulse Ps is smaller than the overload determination value Pj, the rotation overload detector 32 does not detect overload (No), and the process proceeds to step S6.
[0022]
In step S6, the controller 24 determines whether or not the operation of the auger 8 has been completed by the main control unit, and the procedure from step S2 to step S6 described above is performed until the operation is completed (No). Run repeatedly.
FIG. 3 shows temporal changes in the rotational speed and the number of rotations of the auger 8 accompanying the operation of the powder filling machine. As shown in the figure, the operating condition of the auger 8 is defined by an acceleration section, a constant speed section, and a deceleration section of the rotational speed, and a command pulse Pi is output for each control cycle according to this operation pattern. Further, the command rotation number of the auger 8 indicated by a solid line in FIG. 3 is obtained in proportion to the output number of the command pulse Pi, and 1 in FIG. 3 in proportion to the output number of the measurement pulse Pe. The actual number of rotations indicated by the dotted line is obtained. In FIG. 3, for easy understanding, the change in the number of rotations of the auger 8 is simply indicated by a straight line having a constant gradient, but the actual gradient is the largest in the acceleration section and the smallest in the deceleration section.
[0023]
When the rotational load of the auger 8 is normal, the actual number of rotations follows the change in the command number of rotations with a slight delay. For example, when comparing to the time t ₁ which is from the beginning of the first filling cycle and the command pulse output number Pi ₁ obtained by integrating the measured pulse output number Pe _1, smaller towards the measurement pulse output number Pe _1, the deviation between them ( = Pi ₁ −Pe ₁ ), the value becomes the accumulated pulse Ps _{1 at} time t ₁ .
[0024]
During one filling cycle, after the deceleration section of the operation pattern ends, the servo motor 16 is stopped until the auger 8 is driven. Thereafter, the remaining time of the cycle is the standby time of the auger 8.
During the operation of the powder filling machine, the controller 24 monitors the value of the accumulation pulse Ps in real time for each control cycle by the rotation overload detection unit 32 in accordance with the execution of the control routine described above. During operation under normal load, if the actual number of rotations of the auger 8 reaches the predetermined number of rotations without detecting overload in step S5 of the control routine, the controller 24 determines that the operation is ended in step S6 (Yes), The control routine is temporarily terminated without returning to step S2.
[0025]
On the other hand, if the rotational load of the auger 8 increases during the next filling cycle and the value of the accumulation pulse Ps ₂ exceeds the overload judgment value Pj at time t ₂ , for example, the controller 24 at that time It is determined that an excessive load is generated in the rotation, and the rotation overload detection unit 32 establishes overload detection (detection means). In this case, in the control routine of FIG. 2, the determination in step S5 is not satisfied (No), so the controller 24 next proceeds to step S7.
[0026]
In step S <b> 7, the controller 24 stops the servo motor 16. Specifically, the overload detection signal L described above is output from the rotation overload detection unit 32, and the output of the command pulse Pi from the command pulse output unit 28 is discontinued. By stopping the output of the command pulse Ps, the drive of the servo motor 16 is immediately stopped (stop means). Further, the controller 24 ends the execution of the control routine after the execution of step S7.
[0027]
As described above, when an excessive load is generated in the rotation of the auger 8, the actual number of rotations cannot follow the command number of rotations, and the accumulation pulse Ps increases, so that overload can be detected. For this reason, even if the load becomes excessive during one filling cycle (for example, time t ₂ ), this can be detected in real time, and the servo motor 16 can be stopped immediately. As a result, breakage of the auger 8 and the auger shaft 10, and biting and crushing of the granular material in the funnel 2 are prevented in advance.
[0028]
Thereafter, the operator can perform a predetermined recovery operation and resume the operation of the granular material filling machine in a state where restart is possible. At this time, since there is no risk of damage to the machine and biting of the powder, the restoration work is simplified.
The present invention is not limited to the embodiments described above, and can be implemented with various modifications. For example, in the control routine of FIG. 2, when overload detection is established in step S5, the process proceeds to step S7 to stop the drive of the servo motor 16. For example, an alarm sound is generated or the touch panel 34 is displayed. It is also possible to display an alarm. Alternatively, the controller 24 may only issue an alarm and leave the servo motor 16 to the operator's judgment.
[0029]
The overload judgment value Pj set as the threshold value can be re-input through the touch panel 34 in a timely manner even during operation of the powder filling machine. For example, if the symptom at the time of overload detection (the state of machine damage or dusting) is mild, the criteria for the overload judgment value Pj is raised to ease the judgment condition, and conversely, the severe symptom at the time of overload detection If this occurs, it is possible to lower the criteria and make the overload judgment condition more strict.
[0030]
The embodiment of the present invention is not limited to a powder filling machine for packaging containers, and can be implemented as a control device for a bag making filling machine, for example. In this case, the cylindrical portion 6 of the funnel 2 functions as a bag making tube, and a former is assembled on the outer periphery thereof. In addition, a lateral sealing device for the packaging material is provided below the funnel 2 and the granular material is filled in the pillow packaging bag.
[0031]
In addition, there are no particular limitations on the specifications of the devices such as the auger 8 and the servo motor 16, and it goes without saying that the present invention can be implemented with various modifications and equivalent means.
[0032]
【The invention's effect】
The control device (Claim 1) of the granular material filling machine of the present invention can immediately detect even when a rotational overload occurs in the auger during the filling cycle. Therefore, by immediately stopping the driving of the servo motor at this time (claim 2), the breakage of the auger and the crushing of the granular material are surely prevented. Such a function provides a powder filling machine with excellent maintainability in practical use.
[0033]
If an overload is detected using a preset threshold value (Claim 3), the optimum setting can be made for each type of powder filling machine and the type of filling material. Suitable for use. Further, if a threshold value can be appropriately input (Claim 4), adjustment during operation can be performed according to the state of the actual machine, and usability is improved.
Further, by displaying values (deviation, pool pulse) correlated with the rotational load of the auger during operation (claim 5), the operator can arbitrarily stop the operation. In addition, since the displayed value can be easily converted into data for each type of powder filling machine or packing material, the accumulated data can be reflected in the threshold setting.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a powder filling machine according to an embodiment.
FIG. 2 is a flowchart of a control routine executed by a controller as one embodiment.
FIG. 3 is a timing chart showing an auger rotation speed for each filling cycle, temporal changes in the number of rotations, and the like.
[Explanation of symbols]
2 Funnel 8 Auger 16 Servo motor 24 Controller 26 Encoder 34 Touch panel

Claims (5)

On the basis of the number of rotations of the auger screw arranged in the funnel, in the powder filling machine for quantitatively filling the powder from the discharge port of the funnel every predetermined filling cycle,
A servo motor for rotating the auger screw;
A driving means for outputting a command pulse to the servo motor at a predetermined control cycle and driving the servo motor at a command rotation number proportional to the number of output of the command pulse;
Measuring means for measuring the actual number of rotations of the servo motor for each control cycle, and outputting the result as a measurement pulse;
A detecting means for obtaining a deviation between the number of outputs of the command pulse integrated from the beginning of the filling cycle and the number of outputs of the measurement pulse, and detecting rotation overload of the auger screw based on the deviation; A control device for a powder and particle filling machine. 2. The control of the powder filling machine according to claim 1, further comprising a stopping unit that immediately stops the driving of the servo motor when a rotation overload of the auger screw is detected by the detecting unit. apparatus. 3. The control device for a granular material filling machine according to claim 1, wherein the detection unit establishes detection of the rotational overload when the deviation exceeds a preset threshold value. 4. The control apparatus for a powder filling machine according to claim 3, further comprising an input means capable of changing and inputting the setting of the threshold to the detection means. 5. The control apparatus for a granular material filling machine according to claim 1, further comprising display means for numerically displaying the deviation obtained by the detection means.

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