TW201433434A - Mold clamping apparatus and mold clamping method - Google Patents

Abstract

The subject of this invention is to minimize the influence like deformation of molds caused by the stress while correctly measuring the relative position between the molds with high precision and smoothly switching the sensors used during mold clamping stroke. The encoder signal is used for performing feedback control to the servo motor to make molds move. The sensors for mold installation that are secured to close to the opposing part of the molds are used to measure the spacing between the molds. When the interval is exceeded the measurement range of sensor, encoder signal is used to control the servo motor, and when the molds are in the nearest interval, the signal from the sensors for mold installation is used to control the servo motor. Then, when the molds are within the measurement range of the sensors for mold installation, control of servo motor is switched in a continuous manner from the control based on the encoder signal to the control based on the signal of sensors for mold installation.

Description

Clamping device and clamping method

The present invention relates to a mold clamping technique for a mold for press forming, injection molding, die casting, and the like, and more particularly to monitoring or position control of a mold position when the opposite mold is closest.

As a sensor for measuring the position of a moving body, a wired sensor is known. In the line sensor, a magnetic mark in which a magnetic body and a non-magnetic body are arranged or a magnetic mark in which magnets having different polarities are arranged is provided, and a sensor head including a plurality of coils is provided. If the position of the magnetic head is changed by the sensing head, the magnetic interaction between the magnetic mark and the coil changes, and the position of the sensing head relative to the magnetic mark can be obtained.

In a mold clamping apparatus (Mold Clamping Apparatus) using a press molding apparatus, an injection molding apparatus, a die casting apparatus, and the like, there is also a demand for accurately monitoring or controlling the relative position between the upper and lower or left and right molds. Further, in Patent Document 1 (JP2007-283332A), the position of the base of the upper mold is monitored by a line sensor and fed back to the servo motor that drives the upper mold. However, the position to be monitored is the base of the upper mold or the position of the link shaft as the sliding mechanism. The position is not fixed to the lower end of the upper mold due to the stress generated by the contact with the upper and lower molds, the thermal deformation of the mold, and the like. Therefore, even if the position of the upper mold is monitored at the mounting position of the crank or the mounting position of the link shaft, the position of the upper mold relative to the lower mold cannot be correctly controlled, in other words, the interval between the upper and lower molds cannot be properly controlled.

The inventors have further noted that line detectors, which typically have a longer measurement range, have lower resolution. Moreover, it has also been noted that it is necessary to monitor and control the movement of the mold itself, so that even if the position of the sliding mechanism is monitored, the movement of the mold is indirectly monitored. Therefore, the inventors have conducted a discussion on switching control between the other sensors such as the encoder of the servo motor and the line sensor directly mounted on the mold, using a line sensor having a short measuring range. Wherein, when the control is switched discontinuously between the other sensor and the line sensor, the difference between the detected values between the sensors is fed back to the control unit as a large control error. The control of the servo motor is made unstable.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] JP2007-283332A

An object of the present invention is to 1) minimize the influence of stress generated by contact with a mold, temperature change of a mold, and the like, and accurately measure the relative position between opposing molds with high resolution; 2) Smoothly switch the sensor used during the mold stroke.

The mold clamping device of the present invention includes: at least one pair of opposing molds; a servo motor that moves at least one of the molds via the link shaft; and a signal of the encoder of the servo motor or a position of the monitor link shaft The signal of the long range line sensor is used as a control input value, and the control unit performs feedback control on the servo motor; It is characterized in that a mold mounting sensor is provided, and the mold mounting sensor is directly fixed to one of the molds in the vicinity of the opposite portion of the mold for measuring between the opposing molds. Interval and monitor the spacing between the dies by the signal from the mold mounting sensor. The direct fixation to the mold means that it is fixed to the outer circumference of the mold, and is fixed inside the mold. The mold clamping device is, for example, an injection molding device, a press molding device, a die casting molding device, or the like. Instead of monitoring the rotation of the shaft of the servo motor by the encoder, the position of the link shaft or the like can be monitored by using a long-range line sensor.

In the present invention, the position of the other mold based on the distance between the opposing molds, that is, the one of the molds, is measured by a sensor directly fixed to the mold at the position of the mold. Therefore, unlike the encoder of the servo motor and the line sensor that monitors the position of the link shaft, the interval between the dies can be accurately measured. Since the measurement is performed at the position of the mold, even if the mold is deformed due to stress between the molds, or the mold is thermally deformed due to fluctuations in temperature or heat generated by mold clamping, the interval between the molds can be accurately measured. Further, since the sensor can measure the interval in the vicinity of the closest interval of the mold, a sensor having a high resolution in a short measuring range can be used. Moreover, if the interval between the dies is measured, it can be fed back to the servo motor, or it can be judged whether maintenance of the mold clamping device is required.

Preferably, the mold clamping device is provided with means for switching between the signal of the encoder or the signal of the long-range line sensor and the signal of the mold mounting sensor to continuously switch the control input value. Moreover, the servo motor is controlled by the signal of the mold mounting sensor in the clamping area near the clamping position; the signal or the long range of the encoder is located in the distal end away from the clamping position The signal of the line sensor controls the servo motor; and in the middle area between the distal area and the clamping area, The control input value is switched in a continuous manner between the signal of the encoder or the signal of the long-range line sensor and the signal of the sensor for mounting the mold.

In addition, the clamping method of the present invention is performed by the signal of the encoder of the servo motor or the signal of the long-range line sensor of the position of the connecting rod shaft, and the feedback control of the servo motor is performed to face the mold. A mold clamping method in which at least one of the molds is moved by a mold mounting sensor that is directly fixed to one of the molds in the vicinity of the opposing portion of the mold, and monitors the gap between the opposing molds and the mold. In the interval outside the measuring range of the sensor, the servo motor is controlled by the signal of the encoder or the signal of the long-range line sensor that monitors the position of the connecting rod axis; in the closest part of the mold, by the mold mounting The signal of the sensor controls the servo motor; and when the mold enters the measurement range of the mold mounting sensor, the servo motor is controlled from the long range of the signal according to the encoder signal or the position of the monitoring link shaft. The control of the signal of the detector is switched in a continuous manner to the control of the signal according to the sensor for the mold mounting.

When the servo motor is fed back using the signal of the sensor for mounting the mold, the short measurement range becomes a problem. Therefore, a signal from an encoder or the like of the servo motor is used as a control input value in a section other than the measurement range of the sensor for mounting the mold, and between the signal from the mold mounting sensor and the signal from the encoder or the like. The control input values are continuously switched. Thus, even if the control input value is switched, there is no control confusion. Moreover, the control of returning the molds and leaving each other has no effect on the accuracy of the mold clamping. Therefore, for example, the weight w can be fixed to 1 at the time of regression. In this specification, the description of the mold clamping device can also be directly transferred to the mold clamping method.

Preferably, the switching means sets the signal of the encoder P1 or the signal of the long-range line sensor of the position of the monitoring link shaft and the sensor for mounting the mold by the variable weight w of 0 or more and 1 or less. The signal P2 is converted to the control input value P3 by using P3=P1‧w+P2‧(1-w), and is w=1 when the measurement range of the sensor mounting sensor is exceeded, and the mold is in the closest position. In the interval, w=0, and when the mold enters the measurement range of the mold mounting sensor, the weight w is continuously changed from 1 to 0. In this way, the switching of the control input value can be simply and smoothly performed between the encoder and the like and the sensor for mounting the mold.

Preferably, the control unit includes a position control means for converting an error between the command position and the control input value into a speed command, and an error between the speed command and the rate of change of the signal of the encoder per unit time. Converted to a speed command for current command. In this way, since the speed control loop can be controlled by the signal of the encoder capable of acquiring the signal in a short period, the speed control can be accurately performed even if the period in which the signal can be obtained from the sensor is long.

Further, preferably, the mold mounting sensor is a line sensor having a magnetic body rod having a magnetic mark and advancing and retracting the opposing mold; and measuring the advance and retreat position of the magnetic rod a probe; a stopper that determines a movement limit of the magnetic body rod toward the link shaft side; and an elastic body that biases the magnetic body rod toward the link shaft side. And configured to: provide an abutting member that abuts the magnetic rod and moves the magnetic rod along the connecting rod shaft in the opposing mold; and uses the elastic body to be fixed in advance by the position where the stopper is fixed The magnetic rod is biased toward the link shaft side, thereby eliminating vibration of the magnetic rod caused by contact with the abutting member. In this way, the amplitude of the sensor signal can be reduced, and the interval between the dies can be accurately measured.

2‧‧‧Injection molding device

4‧‧‧Upper mold

6‧‧‧Lower mold

8‧‧‧Mobile mold

10‧‧‧Fixed mould

11‧‧‧Marketing

12‧‧‧Connector shaft

14‧‧‧Crank mechanism

16‧‧‧Servo motor

18‧‧‧Injection device

20‧‧‧Control Department

22, 50 ‧ ‧ mold installation line sensor

24‧‧‧The reference plate for the wire sensor for mold installation

26‧‧‧ strain gauge

30‧‧‧Command Generator

31, 32‧‧‧Differentiator

33, 34‧ ‧ amplifier

35‧‧‧ Current amplifier

36‧‧‧Encoder

38, 40‧‧‧Adder

42, 51‧‧‧ shell

44‧‧‧Magnetic rod

45‧‧‧Reference board for magnetic rods

46, 47‧‧ ‧ datum

48‧‧‧Sensor head

49‧‧‧ Elastomers

49a, 49b‧‧‧stops

52‧‧‧ magnetic body

53‧‧‧Non-magnetic body

54‧‧‧Sliding members

55‧‧‧Connecting components

56‧‧‧stops

57‧‧‧ trench

60, 62‧‧ ‧ trajectory

70‧‧‧ cavity

K _p ‧‧‧control constant

K _V ‧‧‧ control constant

P‧‧‧ lowest point

P0‧‧‧ positional instructions

P1‧‧‧ signal

P2‧‧‧ signal

P3‧‧‧ position signal

a, b‧‧‧ deceleration

V‧‧‧speed signal

Vo‧‧‧speed command

W‧‧‧ weight

Fig. 1 is a block diagram showing an injection molding apparatus of an embodiment.

Fig. 2 is a view showing a control unit of the servo motor of the embodiment.

Fig. 3 is a view showing the line sensor of the embodiment.

4 is a waveform diagram of an embodiment, 1) showing the weight of the encoder signal and the line sensor signal, and 2) indicating the angular velocity of the motor.

Fig. 5 is a vertical sectional view showing the line sensor of the preferred embodiment.

Fig. 6 is an explanatory view showing suppression of vibration of the line sensor of the preferred embodiment.

Fig. 7 is a plan view showing the mounting of the wire sensor of the preferred embodiment to the lower mold.

Fig. 8 is a characteristic diagram showing the position of the mold and the end position of the motor in the preferred embodiment.

Fig. 9 is a characteristic diagram showing a mold position and a motor end position in the prior art.

Hereinafter, preferred embodiments for carrying out the invention are shown. The scope of the present invention should be determined in accordance with the scope of the patent application, the description of the specification, and the well-known technology in the field, and the understanding of the ordinary skill in the art.

[Examples] [Basic Embodiments]

Figures 1 through 4 show the basic embodiment and its characteristics. Fig. 1 shows an injection molding apparatus 2 of an embodiment, in which an upper mold 4 is a movable mold which is moved up and down by a ram axis (die bar) 12, and is mounted by injection molding for injection. The synthetic resin moves the mold 8. A fixed mold 10 for injecting synthetic resin is attached to the fixed lower mold 6. The upper mold 4 is guided by, for example, four guide pins 11, and is moved up and down via the link shaft 12 by the crank mechanism 14 and the servo motor 16. In addition, in the lower mold 6 An injection device 18 having a screw pump, a plunger, or the like is connected to inject the synthetic resin into the cavity between the molds 8, 10. Further, the molds 4 and 6 may be disposed to face each other without being placed up and down. Further, in addition to the injection device 18, a press molding device or a die casting device may be used. Instead of the crank mechanism 14, the toggle mechanism 14 or the like may be used instead of the crank mechanism 14.

The control unit 20 performs feedback control of the servo motor 16 by a signal from the encoder and the mold mounting line sensor 22. A mold mounting wire sensor 22 is fixed to the upper portion of the lower mold 6 for measuring the distance between the reference plate 24 and the reference plate 24 of the mold mounting wire sensor attached to the lower portion of the upper mold 4. The combination of the mold mounting wire sensor 22 and the reference plate 24 may be, for example, one pair, two pairs or four pairs, and in the embodiment, one set is provided around each of the molds 4, 6. The mold mounting wire sensor 22 and the reference plate 24 are fixed to the vicinity of the opposing portions of the molds 4 and 6, and the actual interval between the molds 4 and 6 is measured by the mold mounting line sensor 22. The strain gauge 26 corrects the signal of the mold mounting line sensor 22 by detecting the strain generated by the contact of the molds 4, 6, but the strain gauge 26 may not be provided.

FIG. 2 shows the control unit 20 of the servo motor 16. The command generator 30 outputs a position command P0 in accordance with the action pattern of the upper mold 4. The component symbols 31 and 32 are differentiators, 33 and 34 are amplifiers, and 35 is a current amplifier. The current amplifier 35 is controlled such that the drive current of the servo motor 16 coincides with the target value. The servo motor 16 includes an encoder 36, and feeds back the amount of change in the unit time of the signal of the encoder to the differentiator 32 as the speed signal v. Further, for example, the position signals of the four mold mounting line sensors 22 are averaged by the adder 38, and output to the adder 40. When the mold mounting line sensor 22 is one, the adder 38 is not required. Further, the signal of the mold mounting line sensor 22 is subtracted from the axis of the servo motor 16 to the reference plate 24. The amount of displacement is shifted to match the signal of the encoder 36. The adder 40 weight-averages the signal from the encoder 36 and the signal from the side of the mold mounting line sensor 22 of the adder 38 based on the variable weight w input from the command generator 30. The weight w is 0 or more and 1 or less. The weight of the signal P1 from the encoder 36 is set to w, and the weight of the signal P2 from the adder 38 is set to (1-w), from the equation (1) P3 = P1‧w + P2‧ (1-w) (1) The position signal P3 is obtained. Further, in order to generate the weight w, any one of the signals P1, P2, P3 is input to the command generator 30, and the command generator 30 memorizes w with respect to the values of the signals.

The differentiator 31 outputs the difference between the position command P0 and the position signal P3 as a position error, and the amplifier 33 multiplies the position error by the control constant Kp and inputs it to the differentiator 32 as the speed command v0. The difference unit 32 outputs a difference between the speed command v0 and the speed signal v composed of the rate of change of the signal of the encoder 36 as a speed error, and the amplifier 34 multiplies the speed error by the control constant Kv as a current command output to the current amplifier. 35. As described above, the speed signal v from the encoder 36 is used in the control circuit of the speed constituted by the differentiator 32, the amplifier 34, etc., and is used in the control circuit of the position constituted by the differentiator 31, the amplifier 33, etc. The position signal P3 generated by the adder 40 switching the signal P1 of the encoder 36 and the signal P2 of the mold mounting line sensor 22 smoothly. Further, the signal of the strain gauge 26 indicates the stress generated by the contact of the upper and lower molds, and is input to the command generator 30 in order to correct the influence of the mounting position of the mold mounting line sensor 22.

Fig. 3 shows the arrangement of the wire sensor 24 and the like for the mold mounting. The reference plate 24 and the mold mounting line sensor 22 are disposed in the vicinity of the opposing portions of the molds 4 and 6. Further, the mold mounting wire sensor 22 may be disposed on the upper mold 4 side, and the reference plate 24 may be disposed on the lower mold 6 side. The mold mounting line sensor 22 is provided with a housing 42 and can be detached The magnetic rod 44 is freely inserted, and the magnetic rod 44 is provided with a magnetic mark (not shown) having one cycle to a plurality of cycles. The reference plate 45 of the magnetic body rod is fixed to the front end of the magnetic rod 44, and the opposing faces of the reference plates 24 and 45 are used as the reference faces 46 and 47. The magnetic rod 44 is detachably inserted into the casing 42 upward and downward in FIG. 3, and is biased in the protruding direction by the elastic body 49 and the stoppers 49a and 49b, and is provided with four coils. The sensor head 48 detects the magnetic signature. An alternating current is applied to the coil of the sensor head 48 to detect a change in impedance generated by interaction with the magnetic mark as a phase based on the magnetic mark. The magnetic rod 44 is provided with a magnetic mark for determining the measurement range of the mold mounting line sensor 22, for example, in the range of a length of about several mm. The mold mounting wire sensor 22 has a measurement range on the negative side of the mold clamping position, but the upper mold stops at the mold clamping position and becomes a mechanical stop state. Further, in the range beyond the measurement range of the mold mounting line sensor 22, the upper mold position cannot be detected, and the signal of the encoder or the long-range line sensor (not shown) for monitoring the position of the link shaft 12 is used. Signal to control the servo motor.

Figure 4 shows that the signal of the encoder has a weight of w, and the signal of the line sensor has a weight of (1-w). When the line sensor is unable to detect the interval of the upper mold position, w is 1 and the weight w is 0 when the line sensor is in the vicinity of the lowermost end of the stroke of the upper mold. When the line sensor is capable of detecting the position of the upper mold, As shown in 1 of FIG. 4, the weight w is continuously changed from 1 to 0. Therefore, in the section where the signal of the encoder is used, the servo motor can be controlled by the rotation angle of the shaft of the servo motor, and the interval between the signal of the line sensor can be controlled by the interval between the upper mold and the lower mold. Even if the upper mold reaches the lowermost end, the rotation angle of the motor shaft is not fixed due to the deformation of the mold due to the compressive stress, and the vibration is slightly increased as shown in Fig. 4(2).

[Best embodiment]

5 to 8 show a preferred embodiment and its characteristics, which are the same as the basic embodiment of Figs. 1 to 4 except for the portions specifically indicated. 5 is a cross section of the line sensor 50, and the component symbol 51 is a metal case. The movable magnetic body rod 44 is provided with a magnetic mark composed of a magnetic body 52 and a non-magnetic body 53, and is provided with a plurality of magnetic marks. The inside of the sensor head 48 of the coil. A sliding member 54 and a magnetic rod 44 that slide along the groove 57 of the casing 51 are fixed to the reference plate 45, and the reference plate 45, the magnetic rod 44, and the sliding member 54 are integrally slid to the left and right of the drawing. The magnetic body rod 44 and the sliding member 54 are coupled by the coupling member 55, and are biased toward the reference plate 45 side on the left side of the drawing by the elastic body 49. Further, before the reference plate 45 is pressed from the upper mold side, the connecting member 55 is positioned by the stopper 56 by the biasing force of the elastic body 49, and the stroke of the magnetic rod 44 is, for example, about 10 mm. In addition, within the range of the stroke, the interval between the upper and lower dies is measured, and the signal of the encoder and the signal of the line sensor 50 are weighted and averaged at the beginning of the stroke, and fed back to the servo motor, in the middle of the stroke. The upper mold is lowered to the lowest point, and injection molding, die casting, press molding, and the like are performed.

When the magnetic rod 44 is urged sharply toward the right side of the figure by the upper mold, there is a fear that the magnetic rod 44 moves independently from the reference plate on the upper mold side. This vibration can make the control of the servo motor unstable. On the other hand, by using the elastic body 49 and the stopper 56, the magnetic rod body 44 is strongly biased toward the reference plate 45 side from the start, so that the deceleration (absolute value of the acceleration) of the magnetic rod 44 is larger than Deceleration of the upper mold. As a result, no vibration will occur. Further, it is assumed that even if vibration is generated, it is generated only at the beginning of the stroke. Moreover, if the signal of the encoder and the signal of the line sensor 50 are weighted and averaged, the influence of the vibration can be reduced. Figure 6 shows such a mechanism.

Figure 6 is a view showing the position of the upper mold 4 near the lowest point P of the upper mold. With respect to speed and trajectory 60, the trajectory 60 indicates the position and velocity of the upper mold 4. Further, the chain line 62 in the upper right circle is a person who moves as a magnetic body rod 44 of the line sensor from the upper mold and shows its trajectory. If the magnetic body rod 44 is moved independently from the upper mold 4, the deceleration a is proportional to the elastic constant of the elastic body 49. Further, if the elastic body 49 is compressed by the stopper 56 in advance, the deceleration a will be Become bigger. If the deceleration of the upper mold 4 is b, the magnetic rod is pressed against the upper mold by the elastic body when the deceleration a of the magnetic rod 44 is larger than the deceleration b of the upper mold. vibration. Therefore, by selecting the elastic constant of the elastic body 49 and the position of the stopper 56, the vibration of the magnetic rod 44 can be prevented. Since the deceleration a of the magnetic rod is closer to the lowest point, the possibility that the locus 62 of the magnetic rod deviates from the locus 60 of the upper mold is limited to the initial stage of the stroke. At the beginning of the stroke, since the speed control is performed by using the encoder and the line sensor, it is assumed that the vibration is small even if the vibration of the magnetic rod 44 is generated, and the influence on the speed control is small.

Fig. 7 shows the mounting of the line sensor 50 to the lower mold 6. The wired sensor 50 is fixed to, for example, four locations around the cavity 70 such as injection molding, die casting, and press molding. Therefore, the relative position between the upper and lower dies can be accurately measured without being affected by the stress generated by the contact between the upper and lower dies 4 and 6, and the temperature change of the lower mold 6. Further, since the line sensor 50 is disposed at a plurality of positions around the cavity 70, the average value and deviation of the relative positions between the dies can be accurately measured. Further, the reference plate 24 may be provided in the upper mold, or the reference plate 24 may not be provided, and the upper mold itself may be used as the reference plate.

Fig. 8 shows the control result of the preferred embodiment, and Fig. 9 shows the control result of the prior art example in which the servo motor is controlled only by the signal of the encoder. The motor end position of the figure represents the signal of the encoder, which represents the interval near the lowermost end of the stroke of the upper mold. result. In the embodiment, the interval between the upper and lower dies may be controlled at an error of less than 3 μm including the external error of the system at the mold clamping position. Moreover, the measurement error of the line sensor can be, for example, about ±1 μm. Further, the position of the motor end is not fixed due to stress or the like due to contact of the mold. In the embodiment, since the feedback of the signal from the line sensor is controlled by correcting the deformation due to the stress, thermal deformation, etc., if the end position of the upper mold is fixed, the position of the motor end is not fixed. In contrast, in the prior art example, the position of the motor end is fixed, and the end position of the upper mold is unstable.

The embodiment has the following features.

1) Using the mold mounting line sensors 22 and 50 and the reference plate 24 in the vicinity of the opposing portions of the upper and lower molds 4 and 6, the actual interval between the molds 4 and 6 is measured.

2) The gap between the molds 4 and 6 is measured at a high position resolution using the wire-mounting sensors 22 and 50 for the mold mounting in a short measurement range.

3) In the interval other than the measurement range of the mold mounting line sensor 22, 50, the signal of the encoder 36 is used, and the weight of the signal of the encoder 36 and the signal of the line sensor are added by the adder 40. The weights (1-w) vary continuously, so there is no control confusion caused by the switching of the sensors.

4) The speed is controlled by the secondary circuit as the position control, and the secondary circuit of the speed control controls the torque (current) to form multiple feedback control circuits.

5) In the switching between the encoder of the feedback signal and the line sensor, the control circuit is switched in such a manner that only the feedback signal is changed. Therefore, it is preferable to use an encoder and a line sensor to correct the response of the signal, the minimum resolution, and the like by the pre-processing. In addition, even if the feedback signal is switched, the servo parameters such as the parameters of the specified position and the loop gain use the same value.

6) The magnetic body 44 is moved forward by the elastic body 49, the stopper 56, and the like. The mold side is biased, and the deceleration when the magnetic rod 44 is moved independently from the upper mold side is greater than the deceleration of the upper mold. As described above, since the magnetic rod 44 cannot move away from the upper mold side, the operation of the mold to be accurately measured, that is, the operation of the magnetic rod 44 and the operation of the line sensor can be matched in time.

7) The region in which the magnetic rod 44 moves independently from the upper mold side is limited to the state in which the reference plate 45 of the magnetic rod is not in contact with the reference plate 24 of the mold mounting line sensor, and is in contact with the reference plates of both sides. The beginning of the stroke of the magnetic rod 44 is followed. In this area, since the speed control is performed by using the signal of the encoder and the signal of the line sensor, even if the vibration of the magnetic body rod 44 is generated, the influence can be reduced on the control side.

8) As shown in Fig. 7, if a plurality of line sensors 50 and the like are disposed in the fixed lower mold 6 around the cavity 70, the relative positions of the upper and lower molds can be accurately measured. In particular, since the measurement is performed inside the mold and in the vicinity of the cavity, the deformation due to the contact of the mold, the deformation due to the temperature deformation of the mold, and the like do not become errors. In addition, the deviation of the position of the upper and lower dies can also be measured.

9) When the mold clamping is completed, the torque output from the control circuit is cut off, or it is limited to a low torque in order to prevent abnormal heat generation of the motor.

16‧‧‧Servo motor

20‧‧‧Control Department

22‧‧‧Mould installation line sensor

26‧‧‧ strain gauge

30‧‧‧Command Generator

31‧‧‧Differentiator

32‧‧‧Differentiator

33‧‧‧Amplifier

34‧‧‧Amplifier

35‧‧‧ Current amplifier

36‧‧‧Encoder

38‧‧‧Adder

40‧‧‧Adder

P0‧‧‧ positional instructions

P1‧‧‧ signal

P2‧‧‧ signal

P3‧‧‧ position signal

V‧‧‧speed signal

Claims (12)

A mold clamping device comprising: at least one pair of opposing molds; a servo motor for moving at least one of the molds via a link shaft; and a signal of the encoder of the servo motor or monitoring the link shaft a control unit for feedback control of the servo motor as a control input value of the long-range line sensor of the position; the mold clamping device is characterized in that a mold mounting sensor is provided, and the mold is mounted The sensor is directly fixed to one of the molds in the vicinity of the opposite portion of the mold for measuring the distance between the opposing molds and the signal between the molds by the mold mounting sensor The interval is monitored. The clamping device of claim 1, wherein the switching means is provided between the signal of the encoder or the signal of the long-range sensor and the signal of the sensor for mounting the mold. The control input value is switched in a continuous manner; and is configured to: control the servo motor by the signal of the mold mounting sensor in the clamping area near the clamping position; away from the self-closing position In the end region, the servo motor is controlled by the signal of the encoder or the signal of the long-range line detector; and the intermediate region between the distal end region and the clamping region is at the signal or long-range line of the encoder The control input value is switched in a continuous manner between the signal of the sensor and the signal of the sensor for mounting the mold. The clamping device of claim 2, wherein the switching means uses a variable weight w of 0 or more and 1 or less to sense the signal P1 of the encoder or the long range of the position of the link shaft. Signal of the detector, and the letter of the sensor for mounting the mold No. P2, using P3=P1‧w+P2‧(1-w) to convert to the control input value P3, and when it exceeds the measurement range of the mold mounting sensor, it is w=1, and the mold is in the closest In the interval, w=0, and when the mold enters the measurement range of the mold mounting sensor, the weight w is determined by continuously changing the weight w from 1 to 0. The mold clamping device of claim 2, wherein the control unit includes: a position control means for converting an error between the command position and the control input value into a speed command; and a speed command and The error between the rate of change of the signal of the encoder described above per unit time is converted into a speed command means for the current command. The mold clamping device of claim 3, wherein the control unit includes: a position control means for converting an error between the command position and the control input value into a speed command; and a speed command and The error between the rate of change of the signal of the encoder described above per unit time is converted into a speed command means for the current command. The mold clamping device of claim 1, wherein the mold mounting sensor is a line sensor having a magnetic body rod having a magnetic mark and advancing and retracting by a facing mold; a sensing head for advancing and retracting position of the magnetic rod; a stopper for determining a movement limit of the magnetic rod toward the link shaft side; and an elastic body for biasing the magnetic rod toward the rod shaft side; The auxiliary mold is provided with an abutting member that abuts against the magnetic rod and moves the magnetic rod along the connecting rod shaft; and the elastic body is previously fixed at a position fixed by the stopper The magnetic rod is biased toward the link shaft side, thereby eliminating vibration of the magnetic rod caused by contact with the abutting member. The mold clamping device of claim 2, wherein the mold mounting sensor is a line sensor having a magnetic body rod having a magnetic mark and advancing and retracting by a facing mold; measuring a sensing head for advancing and retracting position of the magnetic rod; a stopper for determining a movement limit of the magnetic rod toward the link shaft side; and an elastic body for biasing the magnetic rod toward the rod shaft side; The opposing mold is provided with an abutting member that abuts against the magnetic body rod to move the magnetic rod along the link shaft; and the elastic body is previously fixed at a position fixed by the stopper The magnetic rod is biased toward the link shaft side, thereby eliminating vibration of the magnetic rod caused by contact with the abutting member. The mold clamping device of claim 3, wherein the mold mounting sensor is a line sensor having: a magnetic body rod having a magnetic mark and advancing and retracting by a facing mold; measuring a sensing head for advancing and retracting position of the magnetic rod; a stopper for determining a movement limit of the magnetic rod toward the link shaft side; and an elastic body for biasing the magnetic rod toward the rod shaft side; The auxiliary mold is provided with an abutting member that abuts against the magnetic rod and moves the magnetic rod along the connecting rod shaft; and the elastic body is previously fixed at a position fixed by the stopper The magnetic rod is biased toward the link shaft side, thereby eliminating vibration of the magnetic rod caused by contact with the abutting member. The mold clamping device of claim 4, wherein the mold mounting sensor is a line sensor having: a magnetic body rod having a magnetic mark and advancing and retracting by a facing mold; measuring a sensing head of the advancement and retreat position of the magnetic rod; a stopper for moving the magnetic rod toward the link shaft side; and an elastic body for biasing the magnetic rod toward the link shaft side; and configured to abut the opposite mold a magnetic body rod that moves the magnetic rod along the link shaft; and the elastic body biases the magnetic rod toward the rod shaft side at a position where the stopper is fixed by the stopper, thereby eliminating The vibration of the magnetic rod caused by contact with the abutting member. The mold clamping device of claim 5, wherein the mold mounting sensor is a line sensor having: a magnetic body rod having a magnetic mark and advancing and retracting by a facing mold; measuring a sensing head for advancing and retracting position of the magnetic rod; a stopper for determining a movement limit of the magnetic rod toward the link shaft side; and an elastic body for biasing the magnetic rod toward the rod shaft side; The auxiliary mold is provided with an abutting member that abuts against the magnetic rod and moves the magnetic rod along the connecting rod shaft; and the elastic body is previously fixed at a position fixed by the stopper The magnetic rod is biased toward the link shaft side, thereby eliminating vibration of the magnetic rod caused by contact with the abutting member. The mold clamping device according to any one of claims 1 to 10, wherein the mold clamping device is any one of an injection molding device, a press molding device, and a die casting molding device. A clamping method is a signal of an encoder of a servo motor or a signal of a long-range sensor that monitors the position of the link shaft, and a feedback control of the servo motor causes at least one of the opposing molds to be generated. The method of clamping the movement is characterized in that the distance between the opposing molds is monitored by a mold mounting sensor that is directly fixed to one of the molds in the vicinity of the opposing portion of the mold, and The servo motor is controlled by the signal of the encoder or the signal of the long-range line sensor for monitoring the position of the connecting rod shaft in the interval beyond the measuring range of the sensor for mounting the mold; the mold is closest to the mold In the interval, the servo motor is controlled by the signal of the sensor for mounting the mold; and when the mold enters the measurement range of the sensor for mounting the mold, the control of the servo motor is controlled from the signal according to the encoder or the above The control of the signal of the long-range line sensor of the position of the link shaft is switched in a continuous manner to the control of the signal according to the sensor for the mold mounting.