KR101417600B1 - Injection molding machine - Google Patents

Abstract

And an injection molding machine excellent in molding stability.
The injection molding machine 10 includes a screw 52 to be charged in the mold 30 by weighing and discharging the molten resin in the cylinder 41, a metering motor 55 for rotating the screw 52, A detector 58 for detecting the rotation torque of the metering motor 55, a movement driving unit 43 for moving the screw 52 in the axial direction, a control unit for controlling the metering motor 55 and the movement driving unit 43 And a control unit 80 for controlling the operation of the apparatus. The control unit 80 adjusts the amount of charge by the screw 52 based on the detection value of the detector 58. [

Description

Injection molding machine

The present application claims priority based on Japanese Patent Application No. 2012-070439 filed on March 26, 2012. The entire contents of which are incorporated herein by reference.

The present invention relates to an injection molding machine.

The injection molding machine is provided with an injection device for injecting the molten resin into the mold apparatus. The mold apparatus is composed of a fixed mold and a movable mold, and a cavity is formed between the stationary mold and the movable mold at the time of mold clamping. In the injection apparatus, the molten resin is metered in the cylinder, and the metered molten resin is charged into the cavity of the mold apparatus. The resin solidified and cooled in the cavity space is separated as a molded product after mold opening (see, for example, Patent Document 1).

International Publication No. 2005/068155

The melting rate of the resin material may be uneven due to a variation in the particle diameter (particle diameter) of the resin material or the like. As a result, the molding becomes unstable and the quality of the molded article may be deteriorated.

The present invention has been made in view of the above problems, and an object thereof is to provide an injection molding machine excellent in molding stability.

According to an aspect of the present invention, there is provided an injection molding machine comprising:

A screw for metering the molten resin in the cylinder and filling the mold by injection,

A metering motor for rotating the screw,

A detector for detecting rotation torque of the metering motor,

A movement driving unit for moving the screw in the axial direction,

And a control unit for controlling the metering motor and the moving drive unit,

The control unit adjusts the charged amount by the screw based on the detection value of the detector.

According to another aspect of the present invention, there is provided an injection molding machine,

A screw for measuring the molten resin in the metering cylinder,

A metering motor for rotating the screw,

A detector for detecting rotation torque of the metering motor,

An injection cylinder for receiving the molten resin metered in the metering cylinder,

A plunger for injecting a molten resin in the injection cylinder to fill the mold,

A movement driving unit for moving the plunger in the axial direction,

And a control unit for controlling the metering motor and the moving drive unit,

The control unit adjusts the amount of charge by the plunger based on the detection value of the detector.

According to the present invention, an injection molding machine excellent in molding stability is provided.

1 is a view showing a mold-clamping apparatus of an injection molding machine according to an embodiment of the present invention.
2 is a view showing an injection apparatus of an injection molding machine according to an embodiment of the present invention.
Fig. 3 is a diagram showing time variations of various parameters indicating the state of the injection molding machine according to one embodiment. Fig.
Fig. 4 is a schematic diagram showing a change with time of the rotation torque of the metering motor according to the embodiment. Fig.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and a description thereof will be omitted.

(Mold clamping device)

BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is a view showing a mold clamping apparatus of an injection molding machine according to an embodiment of the present invention. FIG. Fig. 1 shows a mold-shaped state. In the description of the mold clamping apparatus, the moving direction of the movable platen when performing mold closing is referred to as forward, and the moving direction of the movable platen when performing mold opening is referred to as rear.

The injection molding machine 10 includes a frame 11, a stationary platen 12 fixed to the frame 11, and a movable platen 12 movable with respect to the frame 11 at a predetermined distance between the stationary platen 12 And a toggle support (15) arranged as far as possible. Between the stationary platen 12 and the toggle support 15, a plurality of (for example, four) tie bars 16 are laid.

The injection molding machine 10 further includes a movable platen 13 disposed opposite to the stationary platen 12 and disposed so as to be able to move back and forth along the tie bar 16 do. A movable mold 33 is provided on a surface of the movable platen 13 opposed to the fixed platen 12 and a stationary platen 12 is provided on a surface of the stationary platen 12 opposed to the movable platen 13, 32 are mounted. The stationary mold 32 and the movable mold 33 constitute a mold apparatus 30. As shown in Fig.

The injection molding machine 10 includes a toggle mechanism 20 disposed between the movable platen 13 and the toggle support 15, a mold motor 26 for operating the toggle mechanism 20, And a ball screw mechanism 27 as a transmission mechanism for converting the rotary motion generated by the rotary motion sensor 26 into a linear motion and transmitting the linear motion to the toggle mechanism 20. The mold clamping device is constituted by the stationary platen 12, the movable platen 13, the toggle support 15, the toggle mechanism 20, the mold-clamping motor 26, and the like.

The toggle mechanism 20 includes a crosshead 24 capable of advancing and retreating in a direction parallel to the mold opening and closing direction, a second toggle lever 23 pivotally mounted on the crosshead 24, And a toggle arm 22 pivotally mounted on the movable platen 13. The first toggle lever 21 is mounted on the movable platen 13, The first toggle lever 21 and the second toggle lever 23 and the first toggle lever 21 and the toggle arm 22 are linked together. However, the toggle mechanism 20 is a double-toggle mechanism having a so-called innocent five node point, and the upper and lower sides have a symmetrical configuration.

The ball screw mechanism 27 is composed of, for example, a ball screw nut 27a fixed to the crosshead 24 and a ball screw shaft 27b screwed to the ball screw nut 27a. The ball screw shaft 27b is rotatably supported by the toggle support 15. When the output shaft of the mold-clamping motor 26 rotates, the ball screw shaft 27b rotates and the ball screw nut 27a moves forward and backward, so that the crosshead 24 moves forward and backward.

When the toggle mechanism 20 is operated by driving the mold clamping motor 26 in the forward direction and advancing the crosshead 24 as the driven member, the movable platen 13 advances and mold closing is performed.

When the mold clamping motor 26 is further driven in the normal direction, the toggle mechanism 20 generates a mold clamping force which is obtained by multiplying the thrust magnification by the thrust magnification by the mold clamping motor 26. A mold force sensor 17 is mounted on the tie bar 16 which is stretched in accordance with the mold clamping force. The mold clamping force sensor 17 detects the mold clamping force at predetermined time intervals by detecting the deformation (elongation) of the tie bar 16. The detected mold clamping force is sequentially input to the control unit 80. [ A cavity space C is formed between the stationary mold 32 and the movable mold 33 in a mold state. The molten resin is filled in the cavity C and solidified to form a molded article.

Subsequently, the mold-clamping motor 26 is driven in the reverse direction to retreat the crosshead 24, and when the toggle mechanism 20 is operated, the movable platen 13 is retracted and mold-closing is performed. Thereafter, the molded product is protruded from the movable mold 33 by operating the electric ejector apparatus.

However, the mold clamping apparatus of the present embodiment generates the mold clamping force by using the toggle mechanism 20, but it does not use the toggle mechanism 20, but uses the propulsive force generated by the mold clamping motor 26 as the direct mold clamping force, It may be transmitted to the button 13. In addition, the thrust generated by the mold clamping cylinder may be directly transmitted to the movable platen 13 as the mold clamping force. Further, the mold may be opened and closed by a linear motor, and the mold may be molded by an electromagnet.

(Injection apparatus)

2 is a view showing an injection apparatus of an injection molding machine according to an embodiment of the present invention. In the description of the injection apparatus, the injection direction of the resin is referred to as the front and the direction opposite to the injection direction of the resin is referred to as the rear direction, unlike the description of the mold-clamping apparatus.

The injection molding machine 10 further includes an injection apparatus 40 for injecting the molten resin from the nozzle 41 in the heating cylinder 42 and filling the cavity space C in the mold apparatus 30. [ The injection apparatus 40 includes an injection motor (a movement driving section) 43. The rotation of the injection motor 43 is transmitted to the ball screw shaft 44. The ball screw nut 45 which is moved forward and backward by the rotation of the ball screw shaft 44 is fixed to the pressure plate 46. The pressure plate 46 is movable along guide bars 47 and 48 fixed to a base frame (not shown). The forward and backward motion of the pressure plate 46 is transmitted to the screw 52 through the bearing 49, the resin pressure detector (for example, a load cell) 50, and the injection shaft 51. The screw 52 is rotatably disposed in the heating cylinder 42 and is movable in the axial direction. At the rear of the heating cylinder 42, a hopper 53 for supplying resin is provided. Rotary motion of the metering motor 55 is transmitted to the injection shaft 51 through a connecting member 54 such as a belt or a pulley. That is, the injection shaft 51 is rotationally driven by the metering motor 55, so that the screw 52 rotates.

In the weighing process, the metering motor 55 is driven to rotate the screw 52, and the resin pellets supplied to the rear end of the screw 52 are forwarded to the screw 52. In this process, the resin pellets are softened and melted. The molten resin becomes high in front of the screw 52, so that the screw 52 is retracted. In the injection process (also referred to as a filling process), the injection motor 43 is driven to advance the screw 52, and the molten resin is pushed out from the nozzle 41. The molten resin is pushed into the cavity space C through the sprue S, the runner R, the gate G and the like shown in Fig. The force by which the screw 52 presses the molten resin is detected as a reaction force by the resin pressure detector 50. That is, the resin pressure (injection pressure of resin) caught by the screw 52 is detected. The detected resin pressure is input to the control unit 80. [ Since the resin is thermally shrunk by cooling in the cavity space C, the resin pressure (injection pressure of the resin) caught by the screw 52 is set to a predetermined value in the holding pressure process in order to replenish the resin of the heat shrinkable component Lt; / RTI >

The pressure plate 46 is provided with a position detector 57 for detecting the position of the screw 52. The detection signal of the position detector 57 is input to the control unit 80. [ The detection signal of the position detector 57 may be used to detect the moving speed of the screw 52. [

Each of the injection motor 43 and the metering motor 55 may be a servo motor and is provided with encoders 43a and 55a for detecting the number of revolutions. The rotations detected by the encoders 43a and 55a are input to the control unit 80, respectively. The control unit 80 feedback-controls the injection motor 43 and the metering motor 55 based on the detection results of the encoders 43a and 55a.

The control unit 80 is constituted by a microcomputer or the like and has, for example, a ROM for storing a CPU, a control program and the like, a readable recordable RAM for storing calculation results and the like, a timer, a counter, an input interface and an output interface .

(Time variation of various parameters indicating the state of the injection molding machine)

Fig. 3 is a diagram showing changes over time in the actual values of various parameters indicating the state of the injection molding machine according to the embodiment. Fig. 3, the horizontal axis represents time, and the vertical axis represents the position of the screw, the advancing speed of the screw (injection speed of resin), and the pressure of the screw (injection pressure of resin). In Fig. 3, for convenience of explanation, the screw stop time t3-t1 is shown to be longer than actual.

The injection molding machine 10 includes a mold closing process for closing the mold apparatus 30, a mold clamping process for clamping the mold apparatus 30, an injection process for controlling the injection speed of the resin, a holding process for controlling the injection pressure of the resin, A cooling step for solidifying the resin in the mold apparatus 30 after the process, a metering step for measuring the resin for the next molded article, a mold opening step for opening the mold apparatus 30, A projecting step is performed. The injection molding machine repeats these steps to produce a molded article repeatedly. Fig. 3 shows time variations of various parameters in the injection step, the holding step, the cooling step, and the metering step.

The injection process is performed after the mold-forming process. In the injection step, the injection motor 43 is driven to advance the screw 52. The screw 52 pushes the molten resin and ejects the molten resin from the nozzle 41. The molten resin flows into the cavity space C through the sprue S, the runner R, the gate G and the like formed in the mold apparatus 30. [

In the injection process, current is supplied to the injection motor 43 so that the advancing speed of the screw 52 becomes a set value. The setting value of the screw speed may be changed stepwise according to advancement of the screw position. For example, when the detection value of the position detector 57 reaches the set value, the set value of the screw speed is changed.

However, instead of the position detector 57, a timer for measuring the time from the start of the injection process (time t0) may be used for changing the setting value of the screw speed. Since the screw position and time correspond to each other, the same is true even if the set value of the screw speed is changed on the basis of either.

The set value of the screw speed may be approximately 0 (zero) at the time t1 before the start of the pressure holding process. The screw 52 is rapidly decelerated, and the screw 52 stops at time t2. When the screw 52 stops, the screw position hardly changes. Therefore, instead of monitoring the detection value of the position detector 57, the control unit 80 may measure the elapsed time from the start time t1 of the screw stop, do.

Here, "the screw stops" includes not only that the screw 52 is completely stopped but also that the screw 52 is advanced at a slow speed and the screw 52 is retracted at a low speed. When the screw 52 retreats at a low speed, the screw 52 temporarily stops before the low speed retreat.

When the screw 52 stops at time t2, the flow front end of the resin does not reach the end of the cavity C. While the screw 52 is stopped, the flow front end of the resin advances by the compressive force applied to the resin during injection. Since the screw 52 is stopped, the resin gradually decelerates due to the flow resistance.

The conversion from the injection process to the holding process is called V / P conversion. The V / P switching is performed at time t3 when the time from the setting start time t1 of the screw stop reaches the set value. However, when the screw stop is not performed after the initiation of the injection process and before the start of the holding process, the V / P conversion is carried out when the detected value of the position detector 57 reaches the set value or when the timer for measuring the time from the start of the injection process When the measured value reaches the set value.

When the resin is cooled in the cavity C, the resin shrinks. In order to replenish the resin of the heat shrinkable powder, the resin pressure (injection pressure of resin) caught by the screw 52 is maintained at a predetermined pressure in the pressure holding step. A current is supplied to the injection motor 43 so that the detected value of the resin pressure detector 50 becomes a set value. The setting value of the injection pressure of the resin in the holding process may be changed stepwise as time elapses. Since the change of the screw position is small in the holding pressure process, the time from the V / P conversion is measured by the timer of the control unit 80. [

At time t4 when the time from the V / P conversion reaches the set time, the set value of the injection pressure of the resin is returned to approximately 0 (zero), and the pressure holding step is completed. At the completion of the holding process, the gate G, which is the entrance of the cavity C, is clogged with the solidified resin. This state is called a gate seal, and the injection pressure of the resin is not transmitted to the cavity space C, and the back flow of the resin from the cavity space C is prevented.

After completion of the holding process, a cooling process for solidifying the resin in the cavity C is performed. In the cooling step, the resin is thermally shrunk by cooling in the cavity space C in a state where supply of resin to the cavity space C is broken. However, the cooling of the resin proceeds in the injection process and the pressurization process, and the resin surface is solidified at the time of the completion of the holding process.

The weighing process is performed after completion of the holding process. The metering step may be performed during the cooling step to shorten the molding cycle. In the metering step, the metering motor 55 is driven to rotate the screw 52, and the resin pellets supplied to the rear end of the screw 52 are forwarded to the screw 52. In this process, the resin pellets are softened and melted. Since the molten resin is high in front of the screw 52, the screw 52 is retracted. When the screw 52 retracts a predetermined distance and a predetermined amount of molten resin accumulates in front of the screw 52, the rotation of the screw 52 is stopped.

In the weighing process, current is supplied to the metering motor 55 so that the number of revolutions of the screw 52 becomes a set value, and a rotational torque corresponding to the supply current is generated. As a detector for detecting the rotation torque of the metering motor 55, for example, a current sensor 58 is used. The current sensor 58 detects the supply current to the metering motor 55. [ The detection value of the current sensor 58 is supplied to the control unit 80 and converted into the rotation torque of the metering motor 55. [ The rotational torque of the metering motor 55 includes the rotational torque of the screw 52 and the shearing torque of the resin.

Fig. 4 is a schematic diagram showing a change with time of the rotation torque of the metering motor according to the embodiment. Fig.

At the commencement of the weighing process, as shown in Fig. 4, the rotation torque of the metering motor 55 is increased in order to start the screw 52. Fig. When the number of revolutions of the screw 52 becomes the set value, the rotation torque of the metering motor 55 becomes small and stabilizes soon.

Incidentally, there are cases where the melting rate of the resin material is uneven in every shot (one cycle) due to a variation in the particle diameter of the resin material or the like. As the molten resin increases, the viscosity of the molten resin increases, and the rotational torque of the metering motor 55 increases. Further, the more the resin which has started to melt, the more voids are present and the resin density becomes lower. Therefore, the density of the molten resin metered in the heating cylinder 42 is in correlation with the rotation torque of the metering motor 55.

The control unit 80 adjusts the set value relating to the control of the injection motor 43 based on the detected rotation torque of the metering motor 55. [ (Injection amount) of the molten resin can be adjusted in accordance with the density of the molten resin to be weighed in the heating cylinder 42 and the weight of the molten resin to be filled in the mold apparatus 30 in the injection / .

In order to adjust the molding conditions, the rotation torque of the metering motor 55 when the rotation speed of the metering motor 55 becomes the set value and is stabilized may be used. For example, the average value of the rotation torque after the elapse of the set time (for example, half of the metering time T) from the start of the weighing process is used. However, it is also possible to use the integral value of the rotation torque instead of the average value of the rotation torque.

The set values adjusted by the control unit 80 include (1) time (t3-t0) from the start of the injection process to the start of the holding process, or the screw position at the start of the holding process. When the holding pressure time t3 is earlier, the screw moving distance up to the time t3 is shortened and the charged amount of the molten resin is reduced. On the other hand, when the holding pressure start timing t3 is delayed, the screw moving distance to the time t3 becomes longer and the filling amount of the molten resin becomes larger.

When the screw 52 is stopped in the injection process, the setting value adjusted by the control unit 80 is, for example, (2) a time (t1-t0) from the start of the injection process to the start of setting of the screw stop, It may be the screw position of the city. When the start time t1 of the screw stop setting is earlier, the screw travel distance until time t1 becomes shorter, and the charged amount of the molten resin becomes smaller. On the other hand, if the setting start time t1 of the screw stop is delayed, the screw moving distance to the time t1 becomes long, and the charged amount of the molten resin becomes large.

The set value adjusted by the control unit 80 includes (3) a pressure holding time t4-t3 from the start to the end of the pressure holding process. When the holding time is shortened, the screw moving distance is shortened and the charged amount of the molten resin becomes small. On the other hand, if the holding time becomes longer, the screw moving distance becomes longer and the filling amount of the molten resin becomes larger.

The set value adjusted by the control unit 80 includes (4) a resin pressure (injection pressure of resin) caught by the screw 52 in the pressure holding step. Since the holding process is a process for replenishing heat shrinkage due to cooling of the resin, if the holding pressure is lowered, the filling amount of the molten resin becomes smaller. On the other hand, when the holding pressure is increased, the charged amount of the molten resin becomes large. When the set value of the injection pressure of the resin changes stepwise with the lapse of time, at least one set value may be adjusted.

The set value adjusted by the control unit 80 may include at least one of the set values of (1) to (4) above, and the combination is free.

When the detected rotation torque of the metering motor 55 exceeds the upper limit value of the preset range, the control unit 80 sets the set values of (1) to (4) above the preset reference value. When the detected rotation torque of the metering motor 55 is smaller than the lower limit value of the above range, the control unit 80 makes the set values of the above-mentioned (1) to (4) smaller than a preset reference value. The amount of change of each setting value may be predetermined or may be a fixed amount or may be proportional to the amount of deviation of the detected rotation torque of the metering motor 55 from the above range. The reference value is set by the user, for example.

On the other hand, when the detected rotation torque of the metering motor 55 is within the above range, the control unit 80 does not change the set values of (1) to (4), but keeps the preset reference value. By having a width between the upper limit value and the lower limit value, an excessive setting change can be prevented.

The adjustment of the set value by the control unit 80 may be performed each time the metering is performed, or may be performed in accordance with the user's request. The user's request is input from an input unit 94 (see Fig. 2) such as a keyboard and transmitted to the control unit 80. [ The user's request may be made when the particle size distribution or the average particle diameter of the resin material changes, for example, when the lot of the resin pellets is changed or when the mixing ratio of the resin pellets to the recycled material is changed.

The rotational torque of the metering motor 55 is recorded on a recording medium such as a RAM and read out as necessary. The rotational torque of the metering motor 55 is recorded in the recording medium in association with the ID information of the molded product.

The injection molding machine 10 may further include a display unit 92 (see Fig. 2) for displaying the rotational torque of the metering motor 55 used for adjusting the molding conditions of the injection / holding process. The user can confirm the stability of the density of the molten resin metered in the heating cylinder 42.

The display unit 92 is constituted by, for example, a display or the like, and under the control of the control unit 80, displays the rotational torque of the metering motor 55 in accordance with the user's request. The request of the user is input from the input unit 94 and transmitted to the control unit 80. [ The display unit 92 outputs the ID information of the molded product and the rotation torque of the metering motor 55 in association with each other.

Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications and substitutions are possible within the scope of the present invention described in the claims.

For example, the injection apparatus 40 of the above embodiment is a screw inline method in which a screw 52 for measuring the resin and injecting resin is disposed in the heating cylinder 42, but may be a screw preplastication-type system. The injection apparatus of the screw preplastication type includes a screw for measuring the molten resin in the metering cylinder, an injection cylinder for receiving the molten resin metered in the metering cylinder, and a mold for injecting the molten resin in the injection cylinder and filling the mold And a plunger.

In addition, the setting value adjusted by the control device 80 is not limited to the above-mentioned set values of (1) to (4). In the case of the set values other than the above (1) to (4), the magnitude of the rotation torque of the metering motor 55 and the magnitude of the change of the set value may be reversed. That is, when the rotation torque of the metering motor 55 exceeds the predetermined upper limit of the predetermined range, the set value for the control of the injection motor 43 may be small. When the rotation torque of the metering motor 55 is smaller than the lower limit of the predetermined range, the set value for the control of the injection motor 43 may be increased.

In the above embodiment, the set value of the number of revolutions of the screw 52 is constant regardless of the screw position, but may be changed stepwise as the screw 52 retreats. For example, when the detected value of the position detector 57 reaches the set value, the set value of the number of rotations of the screw 52 is changed. In this case, the rotation torque of the metering motor 55 when the screw 52 is rotated at the set value after the change and the rotation torque is stabilized may be used for adjusting the molding conditions.

In the above-described embodiment, a rotary motor is used as the movement drive unit for moving the screw 52 in the axial direction. However, a linear motor or a fluid pressure cylinder may be used, and the configuration of the movement drive unit is not particularly limited.

10 Injection molding machine
12 stationary platen
13 Operation Platen
30 Mold equipment
32 stationary mold
33 Operation mold
42 Heating cylinder (cylinder)
43 Injection motor (mobile drive)
52 Screw
55 Weighing motor
58 Current sensor (detector)
80 control unit

Claims (9)

A screw for metering the molten resin in the cylinder and filling the mold by injection,
A metering motor for rotating the screw,
A detector for detecting rotation torque of the metering motor,
A movement driving unit for moving the screw in the axial direction,
A control unit for controlling the metering motor and the movement driving unit
And,
Wherein the control unit adjusts the charged amount by the screw based on the detection value of the detector. The method according to claim 1,
Wherein the control unit adjusts a set value relating to control of the moving drive unit based on a detection value of the detector. The method of claim 2,
Wherein the set value relating to the control of the movable driving unit includes a time from the start of the injection process to the start of the holding pressure process or a screw position at the start of the holding process. The method according to claim 2 or 3,
The control unit stops the screw after the start of the injection process and before the start of the holding process,
Wherein the setting value relating to the control of the moving drive section includes a time from the start of the injection process to the start of setting of the screw stop or the screw position at the start of setting of the screw stop. The method according to claim 2 or 3,
Wherein the setting value relating to the control of the moving drive section includes a pressure holding time from the start to the end of the pressure holding process. The method according to claim 2 or 3,
Wherein the set value relating to the control of the moving drive section includes a resin pressure acting on the screw in a holding process. The method according to claim 2 or 3,
Wherein,
Wherein when the detected value of the detector exceeds the upper limit value of the predetermined range, the set value relating to the control of the moving drive section is made larger than a predetermined reference value,
Wherein a set value for controlling the moving drive unit is made smaller than a predetermined reference value when the detected value of the detector is smaller than the lower limit value of the predetermined range. The method according to any one of claims 1 to 3,
And a display unit for displaying a detection value of the detector used for the adjustment by the control unit. A screw for measuring the molten resin in the metering cylinder,
A metering motor for rotating the screw,
A detector for detecting rotation torque of the metering motor,
An injection cylinder for receiving the molten resin metered in the metering cylinder,
A plunger for injecting the molten resin in the injection cylinder and filling the mold,
A movement driving unit for moving the plunger in the axial direction,
A control unit for controlling the metering motor and the movement driving unit
And,
Wherein the control unit adjusts the amount of charge by the plunger based on a detection value of the detector.

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