JP2002046713A - Vertical bag making, filling and packing device and its controlling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep always an appropriate constant seal pressure even in the case that a position of a seal member is varied at sealing a packing material, and realize a high quality seal against the packing material. SOLUTION: There is provided a vertical bag forming, filling and packing device having a constitution in which a pair of lateral sealers (seal members) 10a, 10b are driven to open or close through a link mechanism 14 while a servo motor being applied as a drive source and a packing material is held between these pair of lateral sealers 10a, 10b and sealed. A rotational torque of the servo motor is controlled in response to the positions of the lateral sealers 10a, 10b. The rotational torque of the servo motor is controlled in response to the positions of the lateral sealers 10a, 10b in this way, and it becomes possible to keep a constant sealing pressure irrespective of variation in positions of the lateral sealers 10a, 10b even if the positions of the lateral sealers 10a, 10b are varied as a variation in thickness of the packing material or thermal expansion of the lateral sealers 10a, 10b or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vertical bag making and filling apparatus, in which a pair of seal members are opened and closed by using a servo motor as a drive source, and a sealing material is sandwiched between the seal members for sealing. The present invention relates to a vertical bag making / filling and packaging apparatus having a configuration and a control method thereof, and more particularly to control of a thermobotter functioning as a driving source of a seal member.

[0002]

2. Description of the Related Art FIG. 6 is a perspective view showing a schematic configuration of a vertical bag making and filling apparatus. The outline of the vertical bag making / filling / packaging apparatus will be described with reference to the figure. The belt-shaped packaging film (wrapping material) 1 fed from the winding drum 100 is wound around the outer peripheral surface of a cylindrical forming tube 101. The sheet is conveyed downward by the feeding belt 102. On the side of the forming tube 101, a heater 10 for vertical sealing is provided.
3, 103 are provided facing each other, and the overlapping side end of the packaging film 1 wound around the forming tube 101 is
The packaging film 1 is formed into a cylindrical shape by heat fusion (vertical sealing) by the heaters 103 for vertical sealing.

Further, at a predetermined position below the forming tube 101, a pair of horizontal sealers 104, 104 (seal members) are provided so as to face each other with the conveying path of the packaging film 1 interposed therebetween. The packaging film 1 sent to the horizontal sealer 104,
It is sandwiched by 104, and is heat-sealed (horizontal seal) to form a bag. Thereafter, the packaging film 1 further conveyed downward
Is filled through the hollow portion of the forming tube 101, and the horizontal sealer 104,
At the same time, the upper end is thermally sealed (transversely sealed) by 104, and at the same time, the lateral seal portion is vertically cut by a cutter (not shown) built in one of the lateral sealers 104.

FIG. 7A is a front view showing a driving mechanism of a horizontal sealer (seal member) in the above-described vertical bag making and filling apparatus. A pair of horizontal sealers 104 and 10 arranged opposite to each other
4 performs an opening / closing operation along the guide bar 110. A crank member 111 is fixed to a drive shaft of a servomotor 109 as a drive source, and both ends of the crank member 111 and each of the horizontal sealers 104 are connected to a link member 11.
The link mechanism 114 is formed by being rotatably connected to each other by the link members 2 and 113. Then, the servo motor 109
When the drive shaft rotates counterclockwise in the figure, the rotational force is transmitted to the lateral sealers 104, 104 via the link mechanism 114 to perform a closing operation (sliding in a direction approaching each other), and is disposed at an intermediate portion. The packaging film 1 is sandwiched and sealed. On the other hand, when the drive shaft of the servomotor 109 rotates clockwise from the closed position, the rotational force is transmitted to the horizontal sealers 104 and 104 via the link mechanism 114 to perform the opening operation (sliding in the direction away from each other). Do.

[0005] In order to laterally seal the packaging film 1 in an appropriate state by the lateral sealers 104, 104,
It is extremely important that the sealing pressure acting on the packaging film from the horizontal sealers 104 during sealing is always an appropriate value. That is, if the sealing pressure is too high, the fusing of the packaging film 1 occurs, while if it is too low, sealing failure may be caused.

For this reason, Japanese Patent Publication No. Hei 8-25542 discloses that a servomotor, which is a driving source of the horizontal sealer, is maintained at a constant rotational torque value based on the timing at which the horizontal sealer presses the cylindrical film (packaging material). A conventional technique has been disclosed in which the film seal pressure by the horizontal sealer is maintained at an appropriate pressure by performing such control.

Japanese Patent Application Laid-Open No. 6-256563 discloses a torque fluctuation monitoring means for monitoring a torque fluctuation of a servomotor in addition to a servo control unit for controlling the rotation of a servomotor. A conventional technique has been disclosed in which the detected torque fluctuation is fed back to a servo control unit to control the servo motor to always output a constant rotational torque, thereby keeping the seal pressure of the horizontal sealer constant.

[0008]

The prior art disclosed in each of the above publications is based on the premise that if the rotational torque of the servomotor is kept constant, the sealing pressure of the horizontal sealer is kept constant. Although the rotation torque is kept constant, the driving force from the servo motor 109 is transmitted through the link mechanism as shown in FIG.
When the torque is transmitted to the lateral sealers 104 and 104, the seal pressure of the lateral sealers 104 and 104 is not necessarily kept constant even if the rotational torque of the servomotor 109 is kept constant.

That is, the supplied packaging film 1 (packaging material) has a different thickness if the type is different, and even if the type is the same, there is a variation in thickness due to a manufacturing error for each lot. Further, the length of the horizontal sealers 104 in the opening and closing directions also fluctuates due to thermal expansion and the like. And the horizontal sealer 10
The position of the horizontal sealers 104 and 104 at the time of sealing changes with the fluctuation of the thickness of the packaging film 1 sandwiched between the sealing films 4 and 104, the thermal expansion of the horizontal sealers 104 and 104, and the crank member of the link mechanism 114. The angle between 111 and link members 112 and 113 and the angle between guide bar 110 and link members 112 and 113 also vary in relation to the position of the horizontal sealer.

Here, the relationship between the rotational torque of the servomotor 109 and the sealing force applied to the lateral sealers 104, 104 will be described with reference to FIG.
The driving force P0 in the orthogonal direction generated at the tip of the crank member 111 (connection portion with the link member 112) by the rotation torque of 09 is transmitted to the horizontal sealer 104 as the axial component force P1 of the link member 112, and the axial component The force obtained by further decomposing the force P1 in the moving direction of the horizontal sealer 104 is
4 is obtained. Therefore, this horizontal sealer 10
4, the angle between the crank member 111 and the link member 112 and the angle between the guide bar 110 and the link members 112 and 113 even when the rotational torque of the servomotor 109 (that is, the driving force P0) is constant. Fluctuates depending on the angle between.

As described above, the driving force from the servomotor 109 is transmitted to the horizontal sealer 104 via the link mechanism 114.
As long as the structure (toggle structure) is adopted, the sealing pressure when the horizontal sealer 104 seals the packaging film may fluctuate even if the rotational torque of the servomotor 109 is kept constant. . The present invention has been made in view of such circumstances, and realizes high-quality sealing of a packaging material by always maintaining an appropriate constant sealing pressure even when the position of the sealing member at the time of sealing the packaging material changes. The purpose is to do.

[0012]

In order to achieve the above object, the invention of claim 1 relating to a vertical bag making and filling apparatus is provided.
A pair of seal members for sandwiching and sealing the packaging material, a servomotor as a drive source for opening and closing these seal members, a link mechanism for transmitting the driving force of the servomotor to the seal members, and a position detecting means for the seal members And servo motor control means for controlling the rotational torque of the servo motor based on the position of the seal member.

According to a second aspect of the present invention, in the vertical bag making and filling apparatus according to the first aspect, the servo motor control means sets an appropriate sealing pressure when the sealing member seals the packaging material. And a configuration in which the rotational torque of the servomotor is controlled based on the position of the seal member so as to obtain the proper seal pressure set in the seal pressure setting section.

According to a third aspect of the present invention, in the vertical bag making and filling apparatus according to the first or second aspect, the servo motor control means includes a timing setting section for setting a predetermined control switching timing relating to the control of the servo motor. It is characterized in that the servomotor is controlled as follows. That is, based on the control switching timing set in the timing setting section, the servo motor control means sets the control section from the start of the operation of the servo motor to the end of the sealing operation in the first control from the start of the operation to the control switching timing. Section and the second from the control switching timing to the end of the sealing operation
The control of each section is executed as follows, divided into control sections. The first control section controls the rotation speed of the servomotor based on a predetermined rotation speed model set in advance.
The second control section controls the rotation torque of the servomotor as described in claim 1 or 2.

According to a fourth aspect of the present invention, in the vertical bag making and filling apparatus of the first to third aspects, the servo motor control means includes a speed limit setting unit for setting a rotation speed limit value of the servo motor. In parallel with the control of the rotation torque for the motor, the rotation speed of the servomotor is controlled so as not to exceed the rotation speed limit value set in the speed limit setting section.

According to a fifth aspect of the present invention, a pair of seal members are driven to open and close via a link mechanism using a servo motor as a drive source, and a sealing material is sandwiched between the pair of seal members for sealing. The vertical bag-making filling and packaging apparatus having the above configuration is characterized by including a torque control step of controlling the rotation torque of the servomotor based on the position of the seal member.

Further, according to a sixth aspect of the present invention, in the control method of the vertical bag making and filling apparatus according to the fifth aspect, the torque control step sets an appropriate sealing pressure when the sealing member seals the packaging material in advance. In addition, the rotation torque of the servomotor is controlled based on the position of the sealing member so that the proper sealing pressure is obtained.

According to a seventh aspect of the present invention, in the control method of the vertical bag making and filling apparatus according to the fifth or sixth aspect, a predetermined control switching timing relating to the control of the servomotor is set, and the operation of the servomotor is started from the start. The control section until the end of the sealing operation is divided into a first control section from the start of the operation to the control switching timing, and a second control section from the control switching timing to the end of the sealing operation. A speed control step of controlling the rotation speed of the servo motor based on the set predetermined rotation speed model is performed, and the torque control step is performed in the second control section.

According to an eighth aspect of the present invention, in the control method of the vertical bag-making filling and packaging apparatus according to any one of the fifth to seventh aspects, the torque control step includes the step of setting the rotational speed of the servomotor to a preset rotational speed. And speed limit control for restricting the speed so as not to exceed.

As described above, according to the present invention, the rotational torque of the servomotor is controlled based on the position of the seal member. (Especially, even if the position at the time of sealing the packaging material) changes, a constant sealing pressure can be maintained regardless of the position change of the sealing member.
2, 5, 6).

Further, during the period from the start of the operation of the servomotor to the predetermined switching timing, if the rotation speed of the servomotor is controlled, it is possible to avoid the synchronization deviation with the packing material feeding speed of the vertical bag making and filling apparatus and the like. It is possible to stably cope with high-speed operation of the device (claims 3 and 7).

In controlling the servomotor (torque control) by focusing on the rotation torque, the servomotor is controlled so that the rotation speed of the servomotor does not exceed a preset rotation speed. ) Can be prevented (claims 4 and 8).

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a vertical bag making, filling and packaging apparatus will be described below in detail with reference to the drawings. FIG. 1A is a perspective view showing a horizontal sealer driving mechanism of a vertical bag making and filling apparatus to which the present invention is applied. The pair of horizontal sealers 10a and 10b (support members) are mounted on the support plates 11a and 11b and are arranged to face each other. One support plate 11a is composed of two guide rods 1
It is fixed to one end of 2a, 12b. The guide rods 12a and 12b are slidably guided and supported in the lateral direction by support tables 13a and 13b, respectively, and have a connecting plate 15 connected to the link mechanism 14 at the other end.
Further, the other support plate 11b is provided with two guide rods 12
a and 12b, the guide rod 12
It is slidable laterally along the lines a and 12b.

The link mechanism 14 has a function of transmitting the driving force from the servomotor 20 to the supporting plates 11a and 11b and the connecting plate 15, and includes a crank member 16 fixed to a driving shaft of a servomotor (not shown), Link member 17
a, 17b. One link member 17b
Has one end rotatably connected to one end of the crank member 16 and the other end rotatably connected to the support plate 11b. The other link member 17 a has one end rotatably connected to the other end of the crank member 16, and the other end rotatably connected to the connection plate 15.

The link mechanism 14 has a structure in which the link members 17a and 17b are symmetrically connected to the support plate 11b and the connecting plate 15 with respect to the rotation center of the crank member 16. Specifically, the link members 17a and 17b and the crank member 16 are, as schematically shown in FIG.
The link members 17a and 17b are connected to symmetrical positions with respect to the rotation center of the crank member 16 (that is, the center of the drive shaft of the servo motor), and the link members 17a and 17b are set to the same length. Further, the connecting portion between one link member 17b and the supporting plate 11b and the connecting portion between the other link member 17a and the connecting plate 15 are both arranged on the same plane as the plane on which the horizontal sealers 10a and 10b move. It is. By making the link mechanism 14 have such a symmetrical structure, the angle change between the crank member 16 and each of the link members 17a and 17b due to the rotation of the crank member 16 becomes the same, and the support plate 11b and the connecting plate 15 ( That is, each horizontal sealer 10
a, 10b) can be moved symmetrically.

In FIG. 1B, P0 is a driving force in the orthogonal direction generated at the tip of the crank member 16 (the connecting portion with the link members 17a and 17b) by the rotation torque of the servo motor 20, and this driving force is used. P0 is the link member 1
The supporting plates 11a, 1b are used as axial component force P1 of the supporting plates 11a, 17b.
1b and the connecting plate 15, a force obtained by further dissolving the axial component in the moving direction of the horizontal sealers 10a and 10b becomes a sealing force P of the horizontal sealers 10a and 10b. According to the symmetrical link mechanism 14, each of the horizontal sealers 10
The sealing forces P of a and 10b act equally in opposite directions.

FIG. 2 is a block diagram showing a control system of the horizontal sealer driving mechanism. As described above, the horizontal sealer 10
A servo motor 20 is used as a drive source for a and 10b. The servo motor 20 rotates based on an output from a servo amplifier 21. In addition, the servomotor 20 is provided with an encoder 22 for detecting the rotation angle of the drive shaft. The rotation angle detected by the encoder 22 corresponds to the position of the horizontal sealers 10a and 10b connected to the servomotor 20 via the link mechanism 14, and therefore, the horizontal sealer is detected by the position detection signal from the encoder 22. The current positions of 10a and 10b can be obtained. That is, the encoder 22 includes the horizontal sealers 10a,
It functions as a position detecting means of 10b (seal member).
In the present embodiment, the opening position of the horizontal sealers 10a and 10b is set as the origin, and the origin sensor 23 detects the horizontal sealers 10a and 10b that have moved to the origin position.

The servo motor 20 is connected to the control computer 3
0 (servo motor control means).
The control computer 30 includes a central processing unit 31 (hereinafter, referred to as a central processing unit).
Read only memory 32 (hereinafter abbreviated as ROM), random access memory 33
(Hereinafter abbreviated as RAM), the timing monitoring unit 34,
Operation unit 35, setting storage unit 36, output interface 3
7. Includes input interface 38.

The CPU 31 executes various arithmetic processes necessary for controlling the servomotor 20 and outputs a control signal obtained by the arithmetic process to the servo amplifier 21 via the output interface 37. In the present embodiment, as will be described later, a speed control for controlling the rotation speed of the servomotor 20 is executed at a predetermined control switching timing Tc until the timing Tc, and the rotation torque of the servomotor 20 is changed after the timing Tc. The control operation of the CPU 31 is programmed so as to execute the rotational torque control for controlling the rotation torque based on the position detection signal from the encoder 22.

A predetermined program to be executed by the CPU 31 is stored in the ROM 32 in advance. RAM3
Reference numeral 3 has a function of temporarily storing data necessary for the arithmetic processing of the CPU 31. The timing monitor 34 monitors a synchronization signal with the servo motor 20 for feeding the packaging film input from the input interface 38, and outputs a required timing signal at each operation timing in accordance with the synchronization signal. For example, at the start of the closing operation of the horizontal sealers 10a and 10b, the start of the sealing operation, the start of the opening operation, the control switching timing, and the start and end of the ascending section T4, the respective timing signals are sent from the timing monitoring unit 34. Output to CPU 31. The operation unit 35 is configured by a touch panel that also serves as a liquid crystal display unit.
Data necessary for the control of 0 is input.

Various data input from the operation unit 35 are stored in the setting storage unit 36. Examples of data stored in the setting storage unit 36 include the following. Rotation speed model of servo motor 20 Appropriate seal pressure Ps of horizontal sealers 10a and 10b (that is, setting storage unit 36 functions as a seal pressure setting unit) Control switching timing for switching servo motor 20 from speed control to rotation torque control Tc Closing operation section T1 of horizontal sealers 10a, 10b (that is, setting storage section 36 functions as a timing setting section) Sealing operation section T2 of horizontal sealers 10a, 10b Opening operation section T3 of horizontal sealers 10a, 10b Control switching From the timing Tc, the horizontal sealers 10a, 10
Rotation speed limit value in the speed limit control of the servo motor 20 executed in parallel with the torque control in the rising section T4 for gradually increasing the seal pressure of b to the appropriate seal pressure (that is, the setting storage unit 36 sets the speed limit setting). Function as a part.)

The output interface 37 is connected to the servo amplifier 21 and outputs control signals (speed command value, rotation torque command value) generated by the CPU 31 to the servo amplifier 2.
Output to 1. The input interface 38 is connected to the encoder 22 and the origin sensor 23, and inputs a position detection signal from the encoder 22 and an origin signal from the origin sensor 23.

FIG. 3 is a timing chart showing the control operation by the control computer. In the figure, A shows the rotation speed of the servo motor for feeding the packaging film and its operation timing, and B shows the servo motor 20 for driving the horizontal sealers 10a and 10b (hereinafter simply referred to as the horizontal sealers 10a and 10a, A rotation speed model of the servo motor 20 (which drives the servo motor 10b) and its operation timing are shown, and C indicates an opening and closing operation of the horizontal sealers 10a and 10b. D indicates the speed command value of the servomotor 20 and its output timing, and E indicates the servomotor 20
And the output timing thereof. Further, F indicates the rotational speed limit value of the servomotor 20 and its output timing, and G indicates the set proper seal pressure and the set section.

In the vertical bag making and filling apparatus of this embodiment,
A section from the start of the feeding operation of the packaging film to the start of the next feeding operation is defined as one cycle T, and the one cycle T is set by the rotation angle of the servo motor for feeding the packaging film. Then, a section T0 from the start of the feeding operation of the packaging film (that is, the start of one cycle) to the start of the closing operation of the horizontal sealers 10a and 10b, the closing operation section T1 of the horizontal sealers 10a and 10b, and the sealing operation. The section T2 and the opening operation section T3 are set as percentages in one cycle T, so that even when the operation time of one cycle (the rotation angle of the servo motor for feeding out the packaging film) is changed, it is automatically set. Each section T0, T1, T2, T3 is changed.

The control switching timing Tc for switching the servo motor 20 from speed control to rotational torque control is as follows:
The timing is set immediately before the horizontal sealers 10a and 10b reach the closed position (that is, the seal position). Specifically, one of the following timings is set as the control switching timing Tc. First, in the rotation speed model of the servo motor 20 shown in FIG. 3B, a point at which the rotation speed is reduced to a certain rate or less of the maximum speed is set as the control switching timing Tc. For example, the maximum speed of 2
The point in time when the rotation speed is reduced to 0% is defined as control switching timing Tc. Secondly, based on a position detection signal output from the encoder 22 and indicating the moving position of the horizontal sealers 10a and 10b, a point in time when the horizontal sealers 10a and 10b arrive immediately before the closing position is set as the control switching timing Tc.

In a section (first control section) from the start of the closing operation of the horizontal sealers 10a and 10b to the control switching timing Tc, speed control for controlling the rotation speed of the servomotor 20 is executed. You. That is,
The CPU 31 outputs a speed command value (see D in FIG. 3) for controlling the rotation speed of the servomotor 20 based on the rotation speed model shown in FIG. 3B. A corresponding drive signal is output to the servo motor 20.

Further, a section from when the control switching timing Tc is reached to when the sealing operation is completed (second control section).
In, rotation torque control for controlling the rotation torque of the servo motor 20 is executed. In the second control section, the horizontal sealers 10a and 10b are further shifted from the control switching timing Tc.
3 is divided into an ascending section T4 for gradually increasing the sealing pressure to an appropriate sealing pressure, and an actual control section (section indicated by hatching in FIG. 3E) for maintaining the appropriate sealing pressure.

In the actual control section, the CPU 31 detects the position of the horizontal sealers 10a and 10b input from the encoder 22 and indicates the position of the horizontal sealers 10a and 10b.
a, the rotational torque of the servomotor 20 required to give the proper sealing pressure (G in FIG. 3) to
The calculated rotation torque command value is output to the servo amplifier 21. The rotational torque command value is not always constant, but may vary in thickness of the sealed packaging film or the lateral sealer 1.
It changes with the fluctuation of the horizontal seal position caused by the thermal expansion of Oa and 10b.

In the ascending section T4, a rotational torque command value for gradually increasing the rotational torque from 0 to the theoretical value based on the theoretical value of the rotational torque calculated assuming that there is no change in the horizontal seal position is output from the CPU 31. Servo amplifier 21
Output to When a large rotation torque as shown in the actual control section is applied to the servomotor 20 from the moment when the control of the servomotor 20 is switched from the speed control to the rotation torque control, a large impact is applied to the servomotor 20 and the lateral sealer drive mechanism. However, such an impact can be reduced by setting the ascending section T4.

In this embodiment, the servo motor 20
In a second control section in which the CPU 31 is controlled by the rotational torque control, the CPU 31 is controlled in parallel with the rotational torque control based on the rotational speed limit value of the servo motor 20 shown in FIG.
Performs the speed limit control for limiting the rotation speed of the servomotor 20. That is, the servo motor 2
After the control of 0 is switched from the speed control to the rotation torque control, there is a possibility that the rotation speed of the servo motor 20 may rapidly increase particularly before the horizontal sealers 10a and 10b reach the closed positions. In order to avoid such a rapid increase in the rotation speed, the present embodiment executes the speed limit control in parallel. The rotation speed limit value is set to, for example, a value corresponding to the rotation speed model of the servo motor 20 shown in FIG.

Next, the control operation of the CPU 31 will be described with reference to the flowchart shown in FIG. The CPU 31
The operation sections T1, T2, T3 of the horizontal sealers 10a, 10b are always recognized based on the timing signal from the timing monitoring section 34 (S1), and the position detection from the encoder 22 is performed in the closing operation section T1 to the sealing operation section T2. The positions of the horizontal sealers 10a and 10b are detected based on the signal (S2). Subsequently, it is determined whether or not the control switching timing Tc has been reached based on the timing signal from the timing monitoring unit 34 (S3). If not, the servo motor 20 is controlled by speed control (S4). In the speed control, the horizontal sealers 10a and 10a detected in S2 are used.
A speed command value corresponding to the position b is output to the servo motor 20 (S5).

On the other hand, at S3, the control switching timing T
When the arrival time of c is detected, the servo motor 20 is controlled by the rotational torque control (S6). In the rotation torque control, first, it is determined whether or not it is the ascending section T4 based on the timing signal from the timing monitoring unit 34 (S
7) If it is in the ascending section T4, a rotation torque command value is calculated based on the theoretical value of the rotation torque (S8), and the calculated rotation torque command value is output to the servo amplifier 21 (S11). The limit value is output to the servo amplifier 21 (S12).

When the elapse of the ascending section T4 is detected in S7, the positions of the horizontal sealers 10a and 10b are detected based on the position detection signal from the encoder 22 (S7).
9). Then, based on the detected positions of the horizontal sealers 10a and 10b, the appropriate sealing pressure is set to the horizontal sealers 10a and 10b.
b) (S10), and outputs the calculated rotation torque command value to the servo amplifier 21 (S11), and sets the rotation speed limit value to the servo amplifier 2 (S10).
1 (S12).

Returning to S1, if the operation section of the horizontal sealers 10a and 10b is the open operation section T3, the servo motor 20 is controlled by speed control (S13). Also at this time, the position of the horizontal sealers 10a and 10b is detected based on the position detection signal from the encoder 22 (S14), and a speed command value corresponding to the position of the horizontal sealers 10a and 10b is output to the servo motor 20 (S15). ). Then, when the origin signal is input from the origin sensor 23, a series of horizontal sealing operations in one cycle is completed.

FIG. 5 is a diagram showing experimental data conducted by the present inventors. The figure shows the rotational torque value of a servomotor that maintains a constant seal pressure (−350 N), using the horizontal sealer position during sealing as a parameter. In the experiment, a horizontal seal driving device having the configuration shown in FIG. 1 was used. The dimensions of each part of the experimental device were such that the length from the center of the crank member 16 to the connecting portion with the link members 17a and 17b was 5 cm, The length of the link members 17a and 17b is 15 cm,
The total length of the guide rods 12a and 12b is 30 cm, and the opening and closing stroke of the horizontal sealers 10a and 10b is 20 cm.

When the horizontal sealers 10a and 10b are brought into contact with each other without the interposition of the packaging film, the rotational torque value of the servo motor 20 for maintaining a constant sealing pressure (-350N) is indicated by X in FIG. About -0.537N
m. When the package seal having a thickness of 2 mm was pinched, the rotational torque value of the servo motor 20 for maintaining a constant seal pressure (-350 N) was about -0.567 Nm as shown in Y in FIG. . When a packaging seal having a thickness of 5 mm is pressed, a constant sealing pressure (−3) is applied.
The rotational torque value of the servo motor 20 holding 50 N) was about -0.625 Nm as shown by Z in FIG.

As can be seen from the above experimental results, the rotational torque value of the servo motor 20 for maintaining a constant sealing pressure is different from that of the horizontal sealers 10a and 10b due to the variation in the thickness of the packaging film to be pressed.
It can be understood that the value greatly varies depending on the position of.

The present invention is not limited to the above embodiment. For example, the horizontal sealer driving mechanism to which the present invention is applied is not limited to the one having the configuration shown in FIG. 1, and the control system of the mechanism is not limited to the control computer having the configuration shown in FIG.

[0049]

As described above, according to the present invention,
Since the rotation torque of the servomotor is controlled based on the position of the seal member, even if the position of the seal member fluctuates due to a change in the thickness of the packaging material or thermal expansion of the seal member, the position of the seal member is not changed. It is possible to maintain an appropriate sealing pressure regardless of the fluctuation.

[Brief description of the drawings]

FIG. 1A is a perspective view showing a horizontal sealer drive mechanism of a vertical bag making and filling apparatus to which the present invention is applied, and FIG. 1B is a view schematically showing a link mechanism included in the drive mechanism. .

FIG. 2 is a block diagram showing a control system of a horizontal sealer driving mechanism.

FIG. 3 is a timing chart showing a control operation by a control computer.

FIG. 4 is a flowchart illustrating a control operation of a CPU.

FIG. 5 is a diagram showing experimental data performed by the present inventors.

FIG. 6 is a perspective view showing a vertical bag making and filling apparatus.

FIG. 7A is a front view showing a conventional horizontal sealer driving mechanism, and FIG. 7B is a schematic view of the driving mechanism.

[Explanation of symbols]

 1: packaging film 10a, 10b: horizontal sealer (seal member) 11a, 11b: support plate 12a, 12b: guide rod 13a, 13b: support base 14: link mechanism 15: connecting plate 16: crank member 17a, 17b: link member 20: Servo motor 21: Servo amplifier 22: Encoder 23: Origin sensor 30: Control computer 31: Central processing unit 32: ROM 33: RAM 34: Timing monitoring unit 35: Operation unit 36: Setting storage unit 37: Output interface 38: Input interface

Claims (8)

[Claims] 1. A pair of seal members for sandwiching and sealing a packaging material, a servomotor as a drive source for driving the seal members to open and close, a link mechanism for transmitting a driving force of the servomotor to the seal members, A vertical bag filling and packaging apparatus, comprising: a position detecting means for the seal member; and a servo motor control means for controlling a rotational torque of the servo motor based on a position of the seal member. 2. The vertical bag making and filling apparatus according to claim 1, wherein the servo motor control means includes a seal pressure setting section for setting an appropriate seal pressure when the seal member seals the packaging material. A vertical bag-making filling and packaging apparatus, wherein the rotational torque of the servomotor is controlled based on the position of the seal member so as to obtain an appropriate seal pressure set in a seal pressure setting section. 3. The vertical bag making and filling apparatus according to claim 1, wherein said servo motor control means includes a timing setting section for setting a predetermined control switching timing relating to control of said servo motor. A control section from the start of the operation of the servomotor to the end of the sealing operation based on the control switching timing set in the section, a first control section from the start of the operation to the control switching timing,
The second from the control switching timing to the end of the sealing operation
Control section, the first control section controls the rotation speed of the servomotor based on a predetermined rotation speed model set in advance, and as described in claim 1 or 2, in the second control section. A vertical bag making and filling apparatus characterized by controlling the rotation torque of a servomotor. 4. The vertical bag making / filling and packaging apparatus according to claim 1, wherein said servo motor control means includes a speed limit setting unit for setting a speed limit value of said servo motor, and a rotation speed of said servo motor. A vertical bag-making filling and packaging apparatus, wherein a control is performed such that a rotation speed of the servomotor does not exceed a rotation speed limit value set in the speed limit setting section, in parallel with torque control. 5. A vertical bag making / filling and packaging apparatus having a structure in which a pair of seal members are driven to open and close via a link mechanism using a servo motor as a drive source, and a packaging material is sandwiched between these pair of seal members for sealing. 5. The control method according to claim 1, further comprising a torque control step of controlling a rotation torque of the servomotor based on a position of the seal member. 6. The control method for a vertical bag-making filling and packaging apparatus according to claim 5, wherein the torque control step sets an appropriate sealing pressure when the sealing member seals the packaging material in advance, and sets the appropriate sealing pressure. A control method, wherein the rotational torque of the servomotor is controlled based on the position of the seal member so as to obtain a seal pressure. 7. The control method for a vertical bag-making filling and packaging apparatus according to claim 5, wherein a predetermined control switching timing related to the control of the servomotor is set, and a sealing operation is started from an operation start of the servomotor. A first control section from the start of the operation to the control switching timing;
The second from the control switching timing to the end of the sealing operation
The first control section is a speed control step of controlling the rotation speed of the servomotor based on a predetermined rotation speed model set in advance, and the torque control step is performed in the second control section. A control method characterized in that: 8. The control method for a vertical bag-making filling and packaging apparatus according to claim 5, wherein in the torque control step, the rotation speed of the servomotor does not exceed a predetermined rotation speed. A control method characterized by including speed limit control for restricting the speed as described above.