TWI626143B - Injection molding machine - Google Patents

Abstract

The present invention provides an injection molding machine that can assist in adjusting the balance of axial forces. An injection molding machine according to the present invention includes: a plurality of tie rods extending in correspondence with a clamping force; and a controller that controls an axial force of the tie rod, the controller calculating the shaft based on an operation amount that changes the axial force. To force.

Description

Injection molding machine

The present invention relates to an injection molding machine.

The injection molding machine includes a mold clamping device that performs mold closing, mold clamping, and mold opening. The mold clamping device includes a plurality of tie rods that extend in accordance with the mold clamping force (see, for example, Patent Document 1). The clamping force is distributed to a plurality of tie rods so that the tie rods extend. The force that resists the extension of the tie rod is called an axial force. When there is a difference in the effective length of a plurality of tie rods, a difference in axial force is generated between a tie rod with a shorter effective length and a tie rod with a longer effective length. Here, the effective length of the tie bar refers to a distance between members connected by the tie bar, and can be measured, for example, in a state where the clamping force is not functioning. By adjusting the effective length of the tie rod, the balance of the axial force can be adjusted.

(Prior technical literature) (Patent Literature)

Patent Document 1: Japanese Patent Application Laid-Open No. 2004-249637

If the effective length of one tie rod is adjusted, the dispersion state of the clamping force changes, and the axial force of all tie rods may change. Therefore, it is quite troublesome to set the effective length of each tie bar so that the balance of the axial force becomes the target balance.

This invention is made in view of the said subject, The main objective is to provide the injection molding machine which can assist adjustment of the balance of an axial force.

In order to solve the above problems, according to the same aspect of the present invention, there is provided an injection molding machine including: a plurality of tie rods extended corresponding to a mold clamping force; and a controller for controlling an axial force of the tie rod, the controller The aforementioned axial force is calculated based on an operation amount in which the aforementioned axial force is changed.

According to the aspect of the present invention, an injection molding machine capable of assisting in adjusting the balance of the axial force is provided.

10‧‧‧ clamping device

12‧‧‧ fixed platen

13‧‧‧ movable platen

16‧‧‧ Tie

22‧‧‧Axial Force Detector

23‧‧‧Temperature Regulator

24‧‧‧Temperature detector

30‧‧‧Mould device

32‧‧‧Fixed

33‧‧‧ movable mold

70‧‧‧ Operating device

80‧‧‧ display device

82‧‧‧Axial force balance display

83‧‧‧Horizontal axial force balance display

83a‧‧‧Setting value display section

83b‧‧‧ actual value display section

84‧‧‧Vertical axial force balance display

84a‧‧‧Setting value display section

84b‧‧‧ actual value display section

90‧‧‧ Controller

101‧‧‧ axial force setting unit

102‧‧‧Axial force measuring section

103‧‧‧Non-Interference Computing Department

104‧‧‧Temperature setting section

105‧‧‧Temperature Measurement Department

106‧‧‧Temperature instruction section

107‧‧‧Axial force estimation section

108‧‧‧Axial Force Calculation Unit

109‧‧‧ Operation Correction Department

FIG. 1 is a diagram showing a state at the end of mold opening of an injection molding machine according to an embodiment.

Fig. 2 is a diagram showing a state of the injection molding machine according to an embodiment during mold clamping.

Fig. 3 is a view showing a positional relationship of a tie rod of an injection molding machine according to an embodiment, and is a view of a fixed platen as viewed from a movable platen side.

Fig. 4 is a view showing an operation screen of an injection molding machine according to an embodiment.

Fig. 5 is a diagram showing a controller according to an embodiment.

Fig. 6 is a diagram showing an axial force estimation section of a controller according to an embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In each drawing, the same or corresponding structures are denoted by the same or corresponding symbols, and the description is omitted.

FIG. 1 is a diagram showing a state at the end of mold opening of an injection molding machine according to an embodiment. Fig. 2 is a diagram showing a state of the injection molding machine according to an embodiment during mold clamping. The injection molding machine includes a frame Fr, a mold clamping device 10, an operation device 70, a display device 80, a controller 90, and the like.

The controller 90 includes a CPU (Central Processing Unit) 91 and a storage medium 92 such as a memory. The controller 90 executes a program stored in the storage medium 92 to the CPU 91 to control the mold clamping device 10, the operation device 70, the display device 80, and the like.

The mold clamping device 10 performs mold closing, mold clamping, and mold opening of the mold device 30. The mold clamping device 10 includes a fixed platen 12, a movable platen 13, a rear platen 15, a tie rod 16, a toggle mechanism 20, and a mold clamping motor 21. In the following, the moving direction of the movable platen 13 when the mold is closed (the first figure and the second figure are right) The direction) is set to the front, and the moving direction of the movable platen 13 (the left direction in FIG. 1 and FIG. 2) at the time of mold opening will be described below.

The fixed platen 12 is fixed to the frame Fr. A fixed die 32 is attached to a surface of the fixed platen 12 facing the movable platen 13.

The movable platen 13 moves freely along a guide (such as a guide rail) 17 laid on the frame Fr, and moves forward and backward relative to the fixed platen 12. A movable mold 33 is attached to the surface of the movable platen 13 opposite to the fixed platen 12.

By moving the movable platen 13 forward and backward with respect to the fixed platen 12, the mold is closed, closed, and opened. The fixed mold 32 and the movable mold 33 constitute a mold device 30.

The rear platen 15 is connected to the fixed platen 12 at intervals, and is mounted on the frame Fr so as to be movable along the mold opening and closing direction. In addition, the rear pressure plate 15 can also move freely along the guide member laid on the frame Fr. The guide of the rear pressure plate 15 may be used in common with the guide 17 of the movable pressure plate 13.

In this embodiment, the fixed platen 12 is fixed to the frame Fr, and the rear platen 15 is free to move in the mold opening and closing direction with respect to the frame Fr. However, the rear platen 15 may be fixed to the frame Fr, and the fixed platen 12 may be fixed to the frame Fr. Fr moves freely along the mold opening and closing direction.

The tie bar 16 connects the fixed platen 12 and the rear platen 15 at intervals. A plurality of tie rods 16 may be used. Each tie bar 16 is parallel to the mold opening and closing direction and extends in accordance with the mold clamping force.

The toggle mechanism 20 is disposed between the movable platen 13 and the rear platen 15. The toggle mechanism 20 includes a cross head 20a, a plurality of links 20b, 20c, and the like. One of the connecting rods 20b is swingably mounted on the movable platen 13. The other link 20c is swingably mounted on the rear pressure plate 15. The connecting rods 20b and 20c are connected to each other so as to be freely retractable by a bolt or the like. By moving the crosshead 20a forward and backward, the plurality of links 20b, 20c expand and contract, and the movable platen 13 advances and retracts relative to the rear platen 15.

The mold clamping motor 21 is attached to the rear platen 15 and advances and retracts the movable platen 13 by advancing and retreating the crosshead 20a. A motion conversion mechanism is provided between the mold clamping motor 21 and the crosshead 20a to convert a rotary motion of the mold clamping motor 21 into a linear motion and transmit the linear motion to the crosshead 20a. The motion conversion mechanism includes, for example, a ball screw mechanism.

The operation of the mold clamping device 10 is controlled by the controller 90. The controller 90 controls a closed mold process, a mold closing process, an open mold process, and the like.

In the mold closing process, the movable platen 13 is advanced by driving the mold clamping motor 21 so that the movable mold 33 is brought into contact with the fixed mold 32.

During the mold clamping process, the mold clamping force is generated by further driving the mold clamping motor 21. When the mold is closed, a cavity space is formed between the movable mold 33 and the fixed mold 32, and the cavity space can be filled with a molding material in a state. The molding material in the cavity space is cured to become a molded product.

During the mold opening process, the movable platen 13 is moved backward by driving the mold clamping motor 21 to separate the movable mold 33 from the fixed mold 32.

In addition, the mold clamping device 10 of the present embodiment includes a mold clamping motor 21 as a driving source for moving the movable platen 13. However, it may include a hydraulic cylinder instead of the mold clamping motor 21. In addition, the mold clamping device 10 may include a linear motor for mold opening and closing, or may include an electromagnet for mold clamping.

Fig. 3 is a view showing a position of a tie rod of an injection molding machine according to an embodiment; The relationship diagram is a diagram of the fixed platen as viewed from the movable platen side. The injection molding machine has four tie bars 16. When viewed from the mold opening and closing direction, the four tie bars 16 are arranged symmetrically up and down with the horizontal line L1 as the center, and are arranged symmetrically with the vertical line L2 as the center. The upper side than the horizontal line L1 is called the top side, and the lower side than the horizontal line L1 is called the bottom side. In addition, a side closer to the operation device 70 than the vertical line L2 is referred to as an operation side, and an opposite side to the operation device 70 than the vertical line L2 is referred to as an operation side opposite side.

The clamping force is dispersedly applied to the four tie bars 16 so that each tie bar 16 extends. A force resisting the extension of each tie bar 16 is referred to as an axial force. When the effective lengths of the four tie bars 16 are different, a difference in axial force is generated between the tie bars 16 having a shorter effective length and the tie bars 16 having a longer effective length. Here, the effective length of the tie bar 16 refers to the interval between the fixed platen 12 and the rear platen 15 connected by the tie bar 16 and can be measured, for example, in a state where the clamping force is not functioning.

By adjusting the effective length of the tie bar 16, the balance of the axial force can be adjusted. The balance of the axial force is set, for example, such that the surface pressure of the fixed mold 32 and the movable mold 33 becomes a target distribution when the mold is closed. The target distribution can be either uniform or uneven, and can be set according to the situation. It can reduce molding defects.

Since the tie rod 16 is formed of a metal material, the effective length of the tie rod 16 may vary depending on the temperature of the tie rod 16. The higher the temperature of the tie rod 16, the longer the effective length of the tie rod 16. By adjusting the temperature of the tie rod 16, the effective length of the tie rod 16 can be adjusted, and the balance of the axial force can be adjusted.

Therefore, as shown in FIGS. 1 and 2, each tie bar 16 is attached The axial force detector 22, the temperature regulator 23, the temperature detector 24, and the like. The mold clamping device 10 includes an axial force detector 22, a temperature regulator 23, a temperature detector 24, and the like.

The axial force detector 22 detects an axial force of the tie bar 16. The axial force detector 22 is, for example, a strain ceremony, and detects the axial force of the tie rod 16 by detecting the strain of the tie rod 16. The axial force detector 22 outputs a detection result to the controller 90.

The controller 90 sets the temperature of the tie rod 16 so that the actual value of the balance of the axial force becomes a set value. This setting method will be described later.

In addition, although the axial force detector 22 of the above embodiment is a strain ceremony, it may be a piezoelectric type, a capacitive type, a hydraulic type, an electromagnetic type, or the like.

The temperature regulator 23 adjusts the temperature of the tie rod 16. A portion of the tie rod 16 whose temperature is adjusted by the temperature regulator 23 is referred to as a temperature adjustment unit. The temperature regulator 23 includes, for example, a heater such as a heater, and adjusts the temperature of the temperature adjustment unit of the tie rod 16 by heating.

In addition, the temperature adjuster 23 may include a cooler such as a water-cooled jacket, and adjust the temperature of the temperature adjustment section of the tie rod 16 by cooling. The temperature regulator 23 may include both a heater and a cooler.

The controller 90 controls the temperature regulator 23 so that the actual value of the temperature of the temperature adjustment section of the tie rod 16 becomes a set value. Control can be either feedback control or feedforward control.

However, if the temperature of the temperature adjustment part of one tie bar 16 is changed and its effective length is adjusted, the dispersion state of the clamping force is changed, and the axial force of all tie bars may be changed. And if one When the temperature of the temperature adjustment section of each tie rod 16 is changed, the temperature of other tie rods may change due to the movement of heat.

Therefore, the controller 90 manages the balance of the axial force instead of individually managing the axial force of each tie bar 16. With this, although the details will be described later, it can assist in adjusting the balance of the axial force.

In addition, the controller 90 may manage the balance of the axial forces and individually manage each of the axial forces.

The controller 90 is connected to the operation device 70 and the display device 80. The operation device 70 and the display device 80 may be constituted by, for example, a touch panel and integrated. The operation device 70 accepts an input operation performed by a user, and outputs a signal corresponding to the input operation to the controller 90. The display device 80 displays an operation screen corresponding to an input operation in the operation device 70 under the control of the controller 90. The operation screen can be used for setting the injection molding machine. A plurality of operation screens are prepared for switching display or overlapping display. The user operates the operation device 70 while viewing the operation screen displayed on the display device 80 to set the injection molding machine and the like.

In addition, although the operation device 70 and the display device 80 of this embodiment are integrated, they may be provided independently. The operation device 70 may be provided in plural.

Fig. 4 is a view showing an operation screen of an injection molding machine according to an embodiment. The operation screen includes an axial force balance display section 82. The axial force balance display section 82 displays the balance of the axial force. Therefore, compared with the case where each axial force is individually displayed, it is easier for the user to grasp and adjust the surface pressure distribution of the fixed mold 32 and the movable mold 33. Here, the balance of axial forces refers to the axial The state of deviation of the force can be expressed, for example, by the difference in axial force. The difference between the axial forces can be expressed as a ratio (%) to the average of the axial forces.

In addition, the operation screen may further include an axial force display section that individually displays each axial force.

The axial force balance display section 82 includes a horizontal axial force balance display section 83 and a vertical axial force balance display section 84. The horizontal axial force balance display section 83 and the vertical axial force balance display section 84 may be simultaneously displayed on the operation screen. Able to recognize the balance of the two directions.

The horizontal axial force balance display section 83 displays the balance of the axial force in the horizontal direction (hereinafter, also referred to as horizontal axial force balance). The horizontal axial force balance is expressed, for example, by the difference between the average value of the axial forces of the two tie bars 16 on the operation side and the average value of the axial forces of the two tie bars 16 on the opposite side of the operation side. This difference can be expressed as a ratio (%) to the average value of all the axial forces. In the case of a ratio, the clamping force does not change.

If the value of the horizontal axial force balance is set to Nh (%), the average value of the axial force on the operation side becomes 100 + Nh / 2 (%), and the average value of the axial force on the opposite side of the operation side becomes 100- Nh / 2 (%). The value Nh of the horizontal axial force balance is positive, which means that the average value of the axial force on the operation side is larger than the average value of the axial force on the opposite side of the operation side. On the other hand, the negative value Nh of the horizontal axial force balance means that the average value of the axial force on the operation side is smaller than the average value of the axial force on the opposite side of the operation side.

In addition, the relationship between the positive and negative values of the horizontal axial force balance and the magnitude of the axial force on the operating side and the magnitude of the axial force on the opposite side of the operating side can be related. anti.

The horizontal axial force balance display section 83 includes a set value display section 83 a and an actual value display section 83 b. The set value display section 83a displays a set value of the horizontal axial force balance. The real value display section 83b displays the actual value of the horizontal axial force balance. The set value display section 83a and the actual value display section 83b may be displayed on the operation screen at the same time. The deviation between the set value and the actual value can be identified.

The user operates the operation device 70 while viewing the operation screen, and inputs a set value of the horizontal axial force balance to the set value display section 83a. The controller 90 sets the temperature of the tie rod 16 so that the actual value of the horizontal axial force balance becomes a set value.

The vertical axial force balance display unit 84 displays the balance of the axial force in the vertical direction (hereinafter, also referred to as the vertical axial force balance). The vertical axial force balance is expressed by, for example, the difference between the average value of the axial forces of the two tie bars 16 on the top side and the average value of the axial forces of the two tie bars 16 on the bottom side. This difference can be expressed as a ratio (%) to the average value of all the axial forces. In the case of a ratio, the clamping force does not change.

If the value of the vertical axial force balance is Nv (%), the average value of the axial force on the top side becomes 100 + Nv / 2 (%), and the average value of the axial force on the bottom side becomes 100-Nv. /2(%). The value Nv of the vertical axial force balance means that the average value of the axial force on the top side is larger than the average value of the axial force on the bottom side. On the other hand, a negative value Nv of the vertical axial force balance means that the average value of the axial force on the top side is smaller than the average value of the axial force on the bottom side.

In addition, the relationship between the positive and negative values of the vertical axial force balance and the magnitude of the axial force on the top side and the axial force on the bottom side may be reversed.

The vertical axial force balance display section 84 includes a set value display section 84 a and an actual value display section 84 b. The setting value display section 84 a displays a setting value of vertical axial force balance. The actual value display section 84b displays the actual value of the vertical axial force balance. The set value display section 84a and the actual value display section 84b may be displayed on the operation screen at the same time. The deviation between the set value and the actual value can be identified.

The user operates the operation device 70 while viewing the operation screen, and inputs a set value of vertical axial force balance to the set value display section 84a. The controller 90 sets the temperature of the tie rod 16 so that the actual value of the vertical axial force balance becomes a set value.

Fig. 5 is a diagram showing a controller according to an embodiment. As shown in FIG. 5, the controller 90 calculates a set value of the temperature of the temperature adjustment section of the tie rod 16 as an operation amount for changing the axial force based on the set value of the balance of the axial force and the like.

The controller 90 includes an axial force setting section 101, an axial force measurement section 102, a non-interference calculation section 103, a temperature setting section 104, a temperature measurement section 105, and a temperature adjustment command section 106.

The axial force setting unit 101 obtains a set value of the balance of the axial force. For example, the axial force setting unit 101 acquires a setting value of a horizontal axial force balance and a setting value of a vertical axial force balance using an operation screen. The balance of axial force can be expressed by the deviation state of the axial force, such as the difference of the axial force. The difference between the axial forces can be expressed as a ratio (%) to the average of the axial forces. In the case of a ratio, the clamping force does not change.

The axial force measurement unit 102 uses the axial force detector 22 to measure the actual value of the axial force of each tie rod 16.

The non-interference calculation unit 103 obtains the actual value of the axial force balance based on the measurement result of the axial force measurement unit 102. For example, the non-interference calculation unit 103 calculates the actual value of the horizontal axial force balance and the actual value of the vertical axial force balance.

The temperature setting unit 104 calculates the temperature setting value of the temperature adjustment unit of each tie rod 16 based on the setting value of the axial force balance and the like (the difference between the setting value and the actual value in FIG. 5). Compared with the case where the calculation is performed based on the setting values of the respective axial forces, it is easier to deal with the influence of the temperature setting change of the temperature adjustment part of one tie bar 16 on the axial force of the other tie bar 16, and It is easy to set the temperature of the temperature adjustment part of each tie rod 16. In addition, although the details will be described later, the estimated value of the balance of the axial force may be used instead of the actual value of the balance of the axial force.

The temperature setting unit 104 may The temperature of the temperature adjustment section of the tie bar 16 on the operation side and the top side is set to T0 + Th + Tv, The temperature of the temperature adjustment part of the tie bar 16 on the operation side and the bottom side is T0 + Th-Tv, The temperature of the temperature adjustment part of the tie bar 16 on the opposite side of the operation side and on the top side is set to T0-Th + Tv, The temperature of the temperature adjustment part of the tie bar 16 opposite to the operation side and the bottom side is set to T0-Th-Tv, and T0 (° C), Th (° C), and Tv (° C) are set. T0 represents the average value (° C) of the temperature of the temperature adjustment sections of all the tie bars 16, Th represents the balance (difference) of the temperature of the temperature adjustment sections in the horizontal direction, and Tv represents the flatness of the temperature of the temperature adjustment sections in the vertical direction. Balance (bad).

The temperature setting unit 104 may calculate the set value of the temperature of the temperature adjustment unit of each tie bar 16 according to the influence of the temperature setting change of the temperature adjustment unit of the tie bar 16 which is the operation amount on the balance of the axial force. It is possible to consider the influence of the setting change of the temperature of the temperature adjustment part of one tie rod 16 on the axial force of the other tie rod 16. The above effects can be obtained in advance through experiments or simulations, and the effects stored in the storage medium 92 can be read and used. The above effects can be stored in the storage medium 92 in the form of an expression or a table.

The temperature measurement unit 105 measures the actual value of the temperature of the temperature adjustment unit of the tie bar 16 using the temperature detector 24.

The temperature adjustment instruction unit 106 generates an instruction to each of the temperature regulators 23 based on the temperature setting value of the temperature adjustment unit of the tie bar 16 (the difference between the set value and the actual value in FIG. 5).

As described above, the controller 90 calculates the set value of the temperature of the temperature adjustment section of the tie rod 16 as the operation amount for changing the axial force based on the set value of the balance of the axial force and the like. This set value is calculated for each tie bar 16. The controller 90 generates an instruction of the temperature regulator 23 based on the calculated setting value and the like. This command is generated for each temperature regulator 23.

However, it takes time for the actual value of the temperature of the temperature adjustment section of the tie rod 16 to reach the set value. In addition, after the actual value is stabilized to a set value, it takes time until the temperature distribution of the entire mold clamping device 10 is stabilized. Moreover, the actual value of the axial force can only be measured during mold clamping and cannot be measured often.

Therefore, the controller 90 may include the axial force estimation unit 107 (see FIG. 6). The axial force estimation unit 107 estimates the axial force based on the temperature of the temperature adjustment unit of the tie rod 16 as an operation amount for changing the axial force.

While the controller 90 cannot measure the actual value of the axial force by the axial force measurement unit 102 shown in FIG. 5, the controller 90 may appropriately use the estimated value of the axial force instead of the actual value of the axial force, and may appropriately Controlling the temperature regulator 23. Therefore, the time until the axial force of the tie bar 16 is stabilized can be shortened.

For example, as shown in FIG. 6, the axial force estimation unit 107 includes an axial force calculation unit 108 and a calculation correction unit 109.

The axial force calculation unit 108 calculates the axial force based on the temperature of the temperature adjustment unit of the tie bar 16 which is an operation amount for changing the axial force. When calculating the axial force, the axial force calculation unit 108 may use an actual value of the temperature of the temperature adjustment unit.

In addition, when calculating the axial force, the axial force calculation unit 108 of the present embodiment uses the actual value of the temperature of the temperature adjustment unit, but may use the set value of the temperature of the temperature adjustment unit.

When calculating the axial force, the axial force calculation unit 108 uses, for example, the Finite Element Method. According to the finite element method, the time variation of the temperature distribution of the mold clamping device 10 can be calculated, and each axial force can be calculated.

In addition, when calculating the axial force, the axial force calculation unit 108 of this embodiment uses a finite element method, but a heat transfer model based on a thermal diffusion equation or the like may be used. Use specific heat and heat transfer when calculating axial force Rate etc.

The axial force calculation unit 108 can calculate the current value (instantaneous value) of the axial force, and can also calculate the axial force in the transient state. Here, the transient state is a state from the start of control of the temperature regulator 23 until the temperature distribution of the entire mold clamping device 10 is stabilized.

In addition, the current value is not limited to a value in a transient state, and may be a value in a stable state. Here, the steady state refers to a state in which the actual value of the temperature of the temperature adjustment section of the tie bar 16 is stabilized to a set value, and the temperature distribution of the entire mold clamping device 10 is stable.

The axial force calculation unit 108 may calculate, for example, a future value (for example, a stable value) of the axial force instead of the current value of the axial force.

The axial force calculation unit 108 may have the function of the non-interference calculation unit 103 shown in FIG. 5, and may calculate the balance of the axial force. The balance of axial force can be expressed by the deviation state of the axial force, such as the difference of the axial force. The difference between the axial forces can be expressed as a ratio (%) to the average of the axial forces. In the case of a ratio, the clamping force does not change.

The axial force calculation unit 108 calculates a horizontal axial force balance and a vertical axial force balance, for example. The controller 90 can adjust the balance in both directions at the same time. In addition, the controller 90 may adjust only the balance of the axial force in any direction, and the axial force calculation unit 108 may calculate only the balance of the axial force in any direction.

The calculation and correction unit 109 corrects the calculated value of the axial force calculated by the axial force calculation unit 108 based on the actual value of the axial force. Thereby, the estimation accuracy of the axial force by the axial force estimation part 107 can be improved.

The calculation and correction unit 109 calculates, for example, a compensation value of an input value added to the axial force calculation unit 108. The calculation and correction unit 109 calculates a temperature compensation value based on the difference between the actual value of the axial force measured during the mold clamping and the calculated value of the axial force. By adding this temperature compensation value to the actual temperature value, the calculated value of the axial force can be corrected. This temperature compensation value can be used until the actual value of the axial force is measured next time, or it can be updated each time the actual value of the axial force is measured.

In addition, the calculation and correction unit 109 of this embodiment calculates the compensation value of the input value added to the axial force calculation unit 108, but may calculate the compensation value of the output value added to the axial force calculation unit 108.

The embodiments and the like of the injection molding machine have been described above, but the present invention is not limited to the above-mentioned embodiments and the like, and various modifications and improvements can be made within the scope of the gist of the present invention described in the patent application scope.

For example, in the above embodiment, the axial force detector 22, the temperature regulator 23, and the temperature detector 24 are attached to all the tie bars 16, but may be attached to only a part of the tie bars 16. For example, when the controller 90 adjusts both the vertical axial force balance and the horizontal axial force balance, a temperature regulator 23 and a temperature detector 24 may be mounted on only three of the four tie bars 16. When the controller 90 adjusts only the vertical axial force balance, a temperature regulator 23 and a temperature detector 24 may be attached to only one of the tie bars 16 of the top and bottom sides. When the controller 90 adjusts only the vertical axial force balance, the axial force detection may be installed on one of the two tie bars 16 on the top side and one of the two tie bars 16 on the bottom side, respectively.器 22。 22.

Furthermore, in the above-mentioned embodiment, the balance of the axial force is expressed by the difference of the axial force, but it may also be expressed by the ratio of the axial force. For example, the vertical axial force balance can be expressed as the ratio of the average value of the axial force on the top side to the average value of the axial force on the bottom side. Similarly, the horizontal axial force balance can be expressed as the ratio of the average value of the axial force on the operation side to the average value of the axial force on the opposite side of the operation side.

In addition, the controller 90 of the above embodiment uses the temperature of the tie rod 16 as an operation amount for changing the axial force, but may also use the effective length of the tie rod 16. The adjustment of the effective length of the tie rod 16 can use, for example, an external thread 41 formed in the tie rod 16, an internal thread 42 screwed to the external thread 41, and a rotary motor (not shown) that rotates the internal thread 42. The internal thread 42 is attached to the rear platen 15 so as not to be able to move forward and backward. The controller 90 adjusts the effective length of the tie bar 16 by controlling the rotation of the rotary motor. In addition, the internal thread 42 may be attached to either of the two members (the fixed platen 12 and the rear platen 15 in the above embodiment) connected to the tie rod 16, or may be attached to both of them. As the operation amount for changing the axial force, both the temperature of the tie rod 16 and the effective length of the tie rod 16 can be used. The temperature of the tie rod 16 can also be adjusted by increasing or decreasing the power supplied to the heater that heats the tie rod 16. Therefore, the power supplied to the heater can be used as an operation amount for changing the axial force.

In addition, the mold clamping device 10 of the above embodiment is a horizontal mold clamping device in which the mold opening and closing direction is a horizontal direction, but may be a vertical mold clamping device in which the mold opening and closing direction is a vertical direction. The vertical mold clamping device has a lower pressure plate as a fixed pressure plate, an upper pressure plate as a movable pressure plate, a toggle seat, a toggle mechanism and a system. Pole, etc. A lower die is installed on the lower platen, and an upper die is installed on the upper platen. The lower mold and the upper mold constitute a mold device. The lower mold can be mounted on the lower platen via a turntable. The toggle seat is arranged below the lower pressure plate, and is raised and lowered together with the upper pressure plate. The toggle mechanism is arranged between the toggle seat and the lower pressure plate. The tie bar is parallel to the vertical direction and penetrates the lower platen, thereby connecting the upper platen to the toggle seat. The number of tie rods is usually three. The number of tie rods is not particularly limited.

Claims (10)

An injection molding machine, comprising: a plurality of tie rods extending corresponding to a clamping force; and a controller for controlling an axial force of the tie rod, the controller calculating based on an operation amount that changes the axial force. The aforementioned axial force; the controller calculates a set value of a temperature of a tie rod as an operation amount for changing the aforementioned axial force based on the set value of the equilibrium of the aforementioned axial force; the aforementioned controller has an axial force estimation section; The axial force estimation unit estimates the axial force based on a temperature of a tie rod that changes an operation amount of the axial force. The axial force estimation unit uses an axial force detector for detecting the axial force. The detected value of the axial force of the tie rod at the time of mold clamping is detected to correct an estimated value estimated based on the temperature of the tie rod. The injection molding machine according to item 1 of the scope of patent application, wherein the controller calculates the current value of the axial force according to the operation amount. The injection molding machine according to item 1 or 2 of the scope of patent application, wherein the controller calculates the set value of the operation amount according to the calculation value of the axial force. The injection molding machine according to item 1 or 2 of the scope of patent application, wherein the controller corrects the calculated value of the axial force according to the actual value of the axial force. The injection molding machine according to item 1 or 2 of the scope of patent application, wherein the controller calculates the balance of the axial force according to the operation amount. The injection molding machine according to item 1 or 2 of the scope of patent application, wherein the controller calculates the balance of the axial force in the horizontal direction according to the operation amount. The injection molding machine according to item 1 or 2 of the scope of patent application, wherein the controller calculates the balance of the axial force in the vertical direction according to the operation amount. The injection molding machine according to item 5 of the patent application range, wherein the controller uses a difference in the axial force as a balance of the axial force. The injection molding machine according to item 8 of the patent application scope, wherein the controller expresses a difference in the axial force by a ratio with respect to an average of the axial force. The injection molding machine according to claim 1 or 2, wherein the controller uses at least one of a temperature of the tie rod, a length of the tie rod, and power supplied to a heater that heats the tie rod as the The aforementioned operation amount.