JP2021160276A - Injection molding machine - Google Patents

Abstract

To provide a compact injection molding machine.SOLUTION: An injection molding machine comprises a fixed platen on which a fixed mold is mounted, a movable platen on which a movable mold is mounted, a hydraulic cylinder that advances and retreats the movable platen, and an ejector device that advances and retreats the ejector rod. A piston portion of the hydraulic cylinder has a housing section and at least some components of the ejector device are disposed in the housing section.SELECTED DRAWING: Figure 7

Description

The present disclosure relates to an injection molding machine.

For example, an injection molding machine that electrically drives an injection device and hydraulically drives a mold clamping device is known (see Patent Document 1).

Japanese Patent No. 5921736

By the way, a compact injection molding machine is required.

Therefore, in view of the above problems, it is an object of the present invention to provide a compact injection molding machine.

In order to achieve the above object, in one embodiment of the present disclosure, a fixed platen to which a fixed mold is attached, a movable platen to which a movable mold is attached, a hydraulic cylinder for advancing and retreating the movable platen, and an ejector rod are advanced and retreated. Provided is an injection molding machine comprising an ejector device for making the hydraulic cylinder, the piston portion of the hydraulic cylinder has an accommodating portion, and at least a part of the components of the ejector device are arranged in the accommodating portion.

According to the above-described embodiment, a compact injection molding machine can be provided.

It is a figure which shows an example of an injection molding machine. It is a figure which shows an example of an injection molding machine. It is a figure which shows an example of the mold clamping device. It is a figure which shows an example of the mold clamping device. It is a figure which shows an example of the mold clamping device. It is a figure which shows an example of the mold clamping device. It is sectional drawing which shows an example of an ejector apparatus. It is a partially enlarged sectional view which shows another example of an ejector apparatus.

Hereinafter, embodiments will be described with reference to the drawings.

[Injection molding machine configuration]
<Injection molding machine>
FIG. 1 is a diagram showing a state at the time of completion of mold opening of the injection molding machine according to the embodiment. FIG. 2 is a diagram showing a state at the time of mold clamping of the injection molding machine according to the embodiment. In the present specification, the X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction represent the horizontal direction, and the Z-axis direction represents the vertical direction. When the mold clamping device 100 is a horizontal type, the X-axis direction is the mold opening / closing direction, and the Y-axis direction is the width direction of the injection molding machine 10. The negative side in the Y-axis direction is called the operating side, and the positive side in the Y-axis direction is called the counter-operating side.

As shown in FIGS. 1 and 2, the injection molding machine 10 refers to the mold clamping device 100 that opens and closes the mold device 800, the injection device 300 that injects the molding material into the mold device 800, and the mold device 800. It has a moving device 400 for advancing and retreating the injection device 300, a control device 700 for controlling each component of the injection molding machine 10, and a frame 900 for supporting each component of the injection molding machine 10. Further, the injection molding machine 10 includes an ejector device 200 that projects a molded product molded by the mold device 800 from the mold device 800 (movable mold 820). The frame 900 includes a mold clamping device frame 910 that supports the mold clamping device 100 and an injection device frame 920 that supports the injection device 300. The mold clamping device frame 910 and the injection device frame 920 are installed on the floor 2 via the leveling adjuster 930, respectively. The control device 700 is arranged in the internal space of the injection device frame 920. Hereinafter, each component of the injection molding machine 10 will be described.

<Molding device>
In the description of the mold clamping device 100, the moving direction of the movable platen 120 when the mold is closed (for example, the positive direction of the X-axis) is defined as the front, and the moving direction of the movable platen 120 when the mold is opened (for example, the negative direction of the X-axis) is defined as the rear. do.

The mold clamping device 100 performs mold closing, boosting, mold clamping, depressurization, and mold opening of the mold apparatus 800. The mold device 800 includes a fixed mold 810, a movable mold 820, and a movable member 830 that is movably arranged inside (hollow portion) of the movable mold 820.

The mold clamping device 100 is, for example, a horizontal type, and the mold opening / closing direction is a horizontal direction. The mold clamping device 100 includes a fixed platen 110, a movable platen 120, a tie bar 140, a hydraulic cylinder (hydraulic cylinder) 150, and the like.

The fixed platen 110 is fixed to the mold clamping device frame 910. The fixed mold 810 is attached to the surface of the fixed platen 110 facing the movable platen 120.

The movable platen 120 is movably arranged in the mold opening / closing direction with respect to the mold clamping device frame 910. A guide 101 for guiding the movable platen 120 is laid on the mold clamping device frame 910. The movable mold 820 is attached to the surface of the movable platen 120 facing the fixed platen 110. By advancing and retreating the movable platen 120 with respect to the fixed platen 110, the mold device 800 is closed, stepped up, compacted, depressurized, and opened.

The tie bar 140 connects the fixed platen 110 and the cylinder body 151 (see FIGS. 3 to 6) of the hydraulic cylinder 150 at intervals L in the mold opening / closing direction. A plurality of tie bars 140 (for example, four) may be used. The plurality of tie bars 140 are arranged parallel to the mold opening / closing direction and extend according to the mold clamping force.

The hydraulic cylinder 150 is attached to a movable platen. The hydraulic cylinder 150 drives the movable platen 120 by a so-called direct pressure type, and moves the movable platen 120 in the mold opening / closing direction. Details of the configuration of the hydraulic cylinder 150, its drive mechanism, and its operation will be described later (see FIGS. 3 to 6).

The mold clamping device 100 performs a mold closing step, a pressure increasing step, a mold clamping step, a depressurizing step, a mold opening step, and the like under the control of the control device 700. The specific operation of the mold clamping device 100 corresponding to these steps will be described later (see FIGS. 3 to 6).

In the mold closing process, the movable platen 120 is advanced and the movable mold 820 is fixed by driving the hydraulic cylinder 150 and advancing the hydraulic cylinder 150 (piston portion 152 described later) to the mold closing completion position at a set moving speed. Touch the mold 810. The position and moving speed of the hydraulic cylinder 150 are detected by using, for example, a cylinder sensor or the like. The cylinder sensor detects the expansion / contraction position of the hydraulic cylinder 150 and sends a signal indicating the detection result to the control device 700. As a result, the control device 700 performs feedback control (position control of the hydraulic cylinder 150) regarding the position of the hydraulic cylinder 150 (movable platen 120) based on the signal indicating the detection result of the cylinder sensor in the mold clamping step and the mold opening step described later. )It can be performed.

The hydraulic cylinder position detector that detects the position of the hydraulic cylinder 150 and the hydraulic cylinder moving speed detector that detects the moving speed of the hydraulic cylinder 150 are not limited to the cylinder sensor, and general ones can be used.

In the boosting process, the hydraulic cylinder 150 is further driven to control the pressure of the hydraulic cylinder 150 to a predetermined pressure (hereinafter, “target mold clamping pressure”), and the pressure of the hydraulic cylinder 150 is increased to mold clamping. Generate force. The pressure of the hydraulic cylinder 150 is detected by using, for example, a pressure sensor (cylinder pressure sensor) provided in the hydraulic cylinder 150. The cylinder pressure sensor detects the pressure in a predetermined oil chamber inside the hydraulic cylinder 150 (for example, the oil chamber 155 described later), and sends a signal indicating the detection result to the control device 700. As a result, the control device 700 controls feedback on the pressure of the hydraulic cylinder 150 (pressure control of the hydraulic cylinder 150) based on the signal indicating the detection result of the cylinder pressure sensor in the boosting step and the mold clamping step and the depressurizing step described later. )It can be performed.

In the mold clamping step, the hydraulic cylinder 150 is driven to maintain the pressure of the hydraulic cylinder 150 at the target mold clamping pressure. In the mold clamping step, the mold clamping force generated in the pressurizing step is maintained. In the mold clamping step, a cavity space 801 (see FIG. 2) is formed between the movable mold 820 and the fixed mold 810, and the injection device 300 fills the cavity space 801 with a liquid molding material. A molded product is obtained by solidifying the filled molding material.

The number of cavity spaces 801 may be one or plural. In the latter case, a plurality of molded products can be obtained at the same time. The insert material may be arranged in a part of the cavity space 801 and the molding material may be filled in the other part of the cavity space 801. A molded product in which the insert material and the molding material are integrated can be obtained.

In the depressurization step, the mold clamping force is reduced by driving the hydraulic cylinder 150 to reduce the hydraulic cylinder 150 from the target mold clamping pressure.

In the mold opening process, the movable platen 120 is retracted by driving the hydraulic cylinder 150 and retracting the hydraulic cylinder 150 (piston portion 152) from the mold opening start position to the mold opening completion position at a set moving speed, and the movable mold is moved. The 820 is separated from the fixed mold 810. After that, the ejector device 200 projects the molded product from the movable mold 820. The mold opening start position and the mold closing completion position may be the same position.

The setting conditions in the mold closing step, the pressurizing step, and the mold clamping step are collectively set as a series of setting conditions. For example, the moving speed, position (including the mold closing start position, moving speed switching position, mold closing completion position, and mold clamping position) and pressure (including the target mold clamping pressure) of the hydraulic cylinder 150 in the mold closing step and the boosting step. , Mold clamping force, etc. are collectively set as a series of setting conditions. The mold closing start position, the moving speed switching position, the mold closing completion position, and the mold closing position are arranged in this order from the rear side to the front side, and represent the start point and the end point of the section in which the movement speed is set. The moving speed is set for each section. The movement speed switching position may be one or a plurality. The moving speed switching position does not have to be set. Only one or two of the mold clamping position, the target mold clamping pressure, and the mold clamping force may be set.

The setting conditions in the depressurization step and the mold opening step are also set in the same manner. For example, the moving speed and position (mold opening start position, moving speed switching position, and mold opening completion position) of the hydraulic cylinder 150 in the depressurization step and the mold opening process are collectively set as a series of setting conditions. The mold opening start position, the moving speed switching position, and the mold opening completion position are arranged in this order from the front side to the rear side, and represent the start point and the end point of the section in which the movement speed is set. The moving speed is set for each section. The movement speed switching position may be one or a plurality. The moving speed switching position does not have to be set. The mold opening start position and the mold closing completion position may be the same position. Further, the mold opening completion position and the mold closing start position may be the same position.

Instead of the moving speed and position of the hydraulic cylinder 150, the moving speed and position of the movable platen 120 may be set. Further, a target mold clamping pressure or mold clamping force may be set instead of the position of the hydraulic cylinder 150 (for example, the mold clamping position) or the position of the movable platen 120.

The mold clamping device 100 of the present embodiment is a horizontal type in which the mold opening / closing direction is horizontal, but may be a vertical type in which the mold opening / closing direction is in the vertical direction.

<Ejector device>
In the description of the ejector device, similarly to the description of the mold clamping device 100, the moving direction of the movable platen 120 when the mold is closed (for example, the X-axis positive direction) is set to the front, and the moving direction of the movable platen 120 when the mold is opened (for example, X). The negative axis direction) will be described as the rear.

The ejector device is attached to the movable platen 120 and moves forward and backward together with the movable platen 120. The ejector device includes an ejector rod that projects a molded product from the mold device 800, and a drive mechanism that moves the ejector rod in the moving direction (X-axis direction) of the movable platen 120.

The ejector rod comes into contact with the movable member 830 that is freely arranged inside the movable mold 820, and the movable member can be advanced.

The drive mechanism includes, for example, an ejector motor and a motion conversion mechanism that converts the rotational motion of the ejector motor into a linear motion of the ejector rod. The motion conversion mechanism includes a screw shaft and a screw nut screwed onto the screw shaft. A ball or roller may be interposed between the screw shaft and the screw nut.

The ejector device performs the ejection process under the control of the control device 700. In the ejection step, the ejector device advances the movable member 830 to eject the molded product.

The position and moving speed of the ejector rod are detected by using, for example, an ejector motor encoder. The ejector motor encoder detects the rotation of the ejector motor and sends a signal indicating the detection result to the control device 700. Further, the ejector rod position detector for detecting the position of the ejector rod and the ejector rod moving speed detector for detecting the moving speed of the ejector rod are not limited to the ejector motor encoder, and general ones can be used.

<Injection device>
In the description of the injection device 300, unlike the description of the mold clamping device 100 and the description of the ejector device 200, the moving direction of the screw 330 at the time of filling (for example, the negative direction of the X-axis) is set to the front, and the moving direction of the screw 330 at the time of weighing. (For example, the X-axis positive direction) will be described as the rear.

The injection device 300 is installed on the slide base 301, and the slide base 301 is arranged so as to be movable back and forth with respect to the injection device frame 920. The injection device 300 is arranged so as to be able to move forward and backward with respect to the mold device 800. The injection device 300 touches the mold device 800 and fills the cavity space 801 in the mold device 800 with the molding material. The injection device 300 includes, for example, a cylinder 310, a nozzle 320, a screw 330, a weighing motor 340, an injection motor 350, a pressure detector 360, and the like.

The cylinder 310 heats the molding material supplied internally from the supply port 311. The molding material includes, for example, a resin. The molding material is formed, for example, in the form of pellets and is supplied to the supply port 311 in a solid state. The supply port 311 is formed at the rear of the cylinder 310. A cooler 312 such as a water-cooled cylinder is provided on the outer periphery of the rear portion of the cylinder 310. A heater 313 such as a band heater and a temperature detector 314 are provided on the outer periphery of the cylinder 310 in front of the cooler 312.

The cylinder 310 is divided into a plurality of zones in the axial direction (for example, the X-axis direction) of the cylinder 310. A heater 313 and a temperature detector 314 are provided in each of the plurality of zones. The control device 700 controls the heater 313 so that the set temperature is set in each of the plurality of zones and the detected temperature of the temperature detector 314 becomes the set temperature.

The nozzle 320 is provided at the front end of the cylinder 310 and is pressed against the mold device 800. A heater 313 and a temperature detector 314 are provided on the outer periphery of the nozzle 320. The control device 700 controls the heater 313 so that the detected temperature of the nozzle 320 reaches the set temperature.

The screw 330 is rotatably and rotatably arranged in the cylinder 310. When the screw 330 is rotated, the molding material is fed forward along the spiral groove of the screw 330. The molding material is gradually melted by the heat from the cylinder 310 while being fed forward. As the liquid molding material is fed forward of the screw 330 and accumulated in the front of the cylinder 310, the screw 330 is retracted. After that, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is ejected from the nozzle 320 and filled in the mold apparatus 800.

A backflow prevention ring 331 is freely attached to the front portion of the screw 330 as a backflow prevention valve for preventing the backflow of the molding material from the front to the rear of the screw 330 when the screw 330 is pushed forward.

When the backflow prevention ring 331 is advanced, the backflow prevention ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and is relative to the screw 330 up to a closing position (see FIG. 2) that blocks the flow path of the molding material. fall back. As a result, the molding material accumulated in the front of the screw 330 is prevented from flowing backward.

On the other hand, the backflow prevention ring 331 is pushed forward by the pressure of the molding material sent forward along the spiral groove of the screw 330 when the screw 330 is rotated, and the opening position opens the flow path of the molding material. Advance relative to screw 330 to (see FIG. 1). As a result, the molding material is sent to the front of the screw 330.

The backflow prevention ring 331 may be either a co-rotation type that rotates with the screw 330 or a non-co-rotation type that does not rotate with the screw 330.

The injection device 300 may have a drive source for moving the backflow prevention ring 331 forward and backward between the open position and the closed position with respect to the screw 330.

The metering motor 340 rotates the screw 330. The drive source for rotating the screw 330 is not limited to the metering motor 340, and may be, for example, a hydraulic pump.

The injection motor 350 advances and retreats the screw 330. Between the injection motor 350 and the screw 330, a motion conversion mechanism or the like for converting the rotational motion of the injection motor 350 into the linear motion of the screw 330 is provided. The motion conversion mechanism has, for example, a screw shaft and a screw nut screwed onto the screw shaft. A ball, a roller, or the like may be provided between the screw shaft and the screw nut. The drive source for advancing and retreating the screw 330 is not limited to the injection motor 350, and may be, for example, a hydraulic cylinder.

The pressure detector 360 detects the force transmitted between the injection motor 350 and the screw 330. The detected force is converted into pressure by the control device 700. The pressure detector 360 is provided in the force transmission path between the injection motor 350 and the screw 330 to detect the force acting on the pressure detector 360.

The pressure detector 360 sends a signal indicating the detection result to the control device 700. The detection result of the pressure detector 360 is used for controlling and monitoring the pressure received by the screw 330 from the molding material, the back pressure on the screw 330, the pressure acting on the molding material from the screw 330, and the like.

The injection device 300 performs a weighing step, a filling step, a pressure holding step, and the like under the control of the control device 700. The filling process and the pressure holding process may be collectively referred to as an injection process.

In the weighing step, the weighing motor 340 is driven to rotate the screw 330 at a set rotation speed, and the molding material is fed forward along the spiral groove of the screw 330. Along with this, the molding material is gradually melted. As the liquid molding material is fed forward of the screw 330 and accumulated in the front of the cylinder 310, the screw 330 is retracted. The rotation speed of the screw 330 is detected using, for example, a metering motor encoder 341. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends a signal indicating the detection result to the control device 700. Further, the screw rotation speed detector that detects the rotation speed of the screw 330 is not limited to the metering motor encoder 341, and a general screw can be used.

In the weighing step, the injection motor 350 may be driven to apply a set back pressure to the screw 330 in order to limit the sudden retreat of the screw 330. The back pressure on the screw 330 is detected using, for example, a pressure detector 360. The pressure detector 360 sends a signal indicating the detection result to the control device 700. When the screw 330 retracts to the weighing completion position and a predetermined amount of molding material is accumulated in front of the screw 330, the weighing process is completed.

The position and rotation speed of the screw 330 in the weighing process are collectively set as a series of setting conditions. For example, the weighing start position, the rotation speed switching position, and the weighing completion position are set. These positions are arranged in this order from the front side to the rear side, and represent the start point and the end point of the section in which the rotation speed is set. The rotation speed is set for each section. The rotation speed switching position may be one or a plurality. The rotation speed switching position does not have to be set. In addition, back pressure is set for each section.

In the filling step, the injection motor 350 is driven to advance the screw 330 at a set moving speed, and the liquid molding material accumulated in front of the screw 330 is filled in the cavity space 801 in the mold apparatus 800. The position and moving speed of the screw 330 are detected using, for example, an injection motor encoder 351. The injection motor encoder 351 detects the rotation of the injection motor 350 and sends a signal indicating the detection result to the control device 700. When the position of the screw 330 reaches the set position, switching from the filling process to the pressure holding process (so-called V / P switching) is performed. The position where V / P switching is performed is also called the V / P switching position. The set moving speed of the screw 330 may be changed according to the position and time of the screw 330.

The position and moving speed of the screw 330 in the filling step are collectively set as a series of setting conditions. For example, the filling start position (also referred to as “injection start position”), the moving speed switching position, and the V / P switching position are set. These positions are arranged in this order from the rear side to the front side, and represent the start point and the end point of the section in which the movement speed is set. The moving speed is set for each section. The movement speed switching position may be one or a plurality. The moving speed switching position does not have to be set.

The upper limit of the pressure of the screw 330 is set for each section in which the moving speed of the screw 330 is set. The pressure of the screw 330 is detected by the pressure detector 360. When the detected value of the pressure detector 360 is equal to or less than the set pressure, the screw 330 is advanced at the set moving speed. On the other hand, when the detected value of the pressure detector 360 exceeds the set pressure, the screw 330 has a moving speed slower than the set moving speed so that the detected value of the pressure detector 360 is equal to or lower than the set pressure for the purpose of mold protection. To move forward.

After the position of the screw 330 reaches the V / P switching position in the filling step, the screw 330 may be temporarily stopped at the V / P switching position, and then the V / P switching may be performed. Immediately before the V / P switching, instead of stopping the screw 330, the screw 330 may be moved forward or backward at a slow speed. Further, the screw position detector for detecting the position of the screw 330 and the screw moving speed detector for detecting the moving speed of the screw 330 are not limited to the injection motor encoder 351 and general ones can be used.

In the pressure holding step, the injection motor 350 is driven to push the screw 330 forward, and the pressure of the molding material (hereinafter, also referred to as “holding pressure”) at the front end of the screw 330 is maintained at a set pressure in the cylinder 310. The remaining molding material is pushed toward the mold device 800. The shortage of molding material due to cooling shrinkage in the mold apparatus 800 can be replenished. The holding pressure is detected using, for example, a pressure detector 360. The pressure detector 360 sends a signal indicating the detection result to the control device 700. The set value of the holding pressure may be changed according to the elapsed time from the start of the holding pressure step and the like. A plurality of holding pressures and holding times for holding the holding pressures in the holding pressure step may be set respectively, and may be collectively set as a series of setting conditions.

In the pressure holding step, the molding material in the cavity space 801 in the mold apparatus 800 is gradually cooled, and when the pressure holding step is completed, the inlet of the cavity space 801 is closed with the solidified molding material. This state is called a gate seal, and the backflow of the molding material from the cavity space 801 is prevented. After the pressure holding step, the cooling step is started. In the cooling step, the molding material in the cavity space 801 is solidified. A weighing step may be performed during the cooling step for the purpose of shortening the molding cycle time.

The injection device 300 of the present embodiment is an in-line screw type, but may be a pre-plastic type or the like. The pre-plastic injection device supplies the molded material melted in the plasticized cylinder to the injection cylinder, and injects the molding material from the injection cylinder into the mold device. In the plasticized cylinder, a screw is rotatably and irreversibly arranged, or a screw is rotatably and movably arranged. On the other hand, a plunger is arranged in the injection cylinder so as to be able to move forward and backward.

Further, the injection device 300 of the present embodiment is a horizontal type in which the axial direction of the cylinder 310 is horizontal, but may be a vertical type in which the axial direction of the cylinder 310 is in the vertical direction. The mold clamping device combined with the vertical injection device 300 may be vertical or horizontal. Similarly, the mold clamping device combined with the horizontal injection device 300 may be horizontal or vertical.

As described above, in the present embodiment, the injection device 300 is electrically driven by electric actuators such as the metering motor 340 and the injection motor 350. As a result, the injection device 300 can be relatively responsive to the control command from the control device 700 as compared with the case where the injection device 300 is hydraulically driven. Therefore, the injection molding machine 10 can realize relatively excellent controllability of the injection device 300.

<Mobile device>
In the description of the moving device 400, similarly to the description of the injection device 300, the moving direction of the screw 330 at the time of filling (for example, the negative direction of the X-axis) is set to the front, and the moving direction of the screw 330 at the time of weighing (for example, the positive direction of the X-axis). Will be described as backward.

The moving device 400 advances and retreats the injection device 300 with respect to the mold device 800. Further, the moving device 400 presses the nozzle 320 against the mold device 800 to generate a nozzle touch pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a drive source, a hydraulic cylinder 430 as a hydraulic actuator, and the like.

The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a pump that can rotate in both directions, and by switching the rotation direction of the motor 420, the hydraulic fluid (for example, oil) is sucked from one of the first port 411 and the second port 412 and discharged from the other. To generate hydraulic pressure. Further, the hydraulic pump 410 can also suck the hydraulic fluid from the tank and discharge the hydraulic fluid from either the first port 411 or the second port 412.

The motor 420 operates the hydraulic pump 410. The motor 420 drives the hydraulic pump 410 in the rotational direction and rotational torque according to the control signal from the control device 700. The motor 420 may be an electric motor or an electric servomotor.

The hydraulic cylinder 430 has a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed to the injection device 300. The piston 432 divides the inside of the cylinder body 431 into a front chamber 435 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed to the fixed platen 110.

The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via the first flow path 401. The hydraulic fluid discharged from the first port 411 is supplied to the anterior chamber 435 via the first flow path 401, so that the injection device 300 is pushed forward. The injection device 300 is advanced and the nozzle 320 is pressed against the fixed mold 810. The anterior chamber 435 functions as a pressure chamber that generates a nozzle touch pressure of the nozzle 320 by the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

On the other hand, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via the second flow path 402. The hydraulic fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second flow path 402, so that the injection device 300 is pushed backward. The injection device 300 is retracted and the nozzle 320 is separated from the fixed mold 810.

In the present embodiment, the moving device 400 includes the hydraulic cylinder 430, but the present invention is not limited to this. For example, instead of the hydraulic cylinder 430, an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into a linear motion of the injection device 300 may be used.

<Control device>
The control device 700 is composed of, for example, a computer, and has a CPU (Central Processing Unit) 701, a storage medium 702 such as a memory, an input interface 703, and an output interface 704 as shown in FIGS. The control device 700 performs various controls by causing the CPU 701 to execute the program stored in the storage medium 702. Further, the control device 700 receives a signal from the outside through the input interface 703 and transmits the signal to the outside through the output interface 704.

The control device 700 repeatedly performs a weighing process, a mold closing process, a pressure increasing process, a mold clamping process, a filling process, a pressure holding process, a cooling process, a depressurizing process, a mold opening process, a protrusion process, and the like to produce a molded product. Manufacture repeatedly. A series of operations for obtaining a molded product, for example, an operation from the start of a weighing process to the start of the next measuring process is also referred to as a "shot" or a "molding cycle". Further, the time required for one shot is also referred to as "molding cycle time" or "cycle time".

A single molding cycle includes, for example, a weighing step, a mold closing step, a pressurizing step, a mold clamping step, a filling step, a pressure holding step, a cooling step, a depressurizing step, a mold opening step, and a protrusion step in this order. The order here is the order of starting each process. The filling step, the pressure holding step, and the cooling step are performed during the mold clamping step. The start of the mold clamping step may coincide with the start of the filling step. The end of the depressurization process coincides with the start of the mold opening process.

In addition, a plurality of steps may be performed at the same time for the purpose of shortening the molding cycle time. For example, the weighing step may be performed during the cooling step of the previous molding cycle or during the mold clamping step. In this case, the mold closing step may be performed at the beginning of the molding cycle. Further, the filling step may be started during the mold closing step. Further, the ejection step may be started during the mold opening step. If an on-off valve that opens and closes the flow path of the nozzle 320 is provided, the mold opening step may be started during the weighing step. This is because even if the mold opening process is started during the measuring process, if the on-off valve closes the flow path of the nozzle 320, the molding material does not leak from the nozzle 320.

In addition, one molding cycle includes steps other than the weighing step, the mold closing step, the pressurizing step, the mold clamping step, the filling step, the pressure holding step, the cooling step, the depressurizing step, the mold opening step, and the protrusion step. You may.

For example, after the completion of the pressure holding step and before the start of the weighing step, a pre-weighing suckback step of retracting the screw 330 to a preset weighing start position may be performed. The pressure of the molding material accumulated in front of the screw 330 before the start of the weighing process can be reduced, and the screw 330 can be prevented from suddenly retreating at the start of the weighing process.

Further, after the completion of the weighing step and before the start of the filling step, a post-weighing suckback step may be performed in which the screw 330 is retracted to a preset filling start position (also referred to as “injection start position”). The pressure of the molding material accumulated in front of the screw 330 before the start of the filling step can be reduced, and the leakage of the molding material from the nozzle 320 before the start of the filling step can be prevented.

The control device 700 is connected to an operation device 750 that accepts an input operation by a user and a display device 760 that displays a display screen. The operation device 750 and the display device 760 may be composed of, for example, a touch panel and may be integrated. The touch panel as the display device 760 displays the display screen under the control of the control device 700. Information such as the setting of the injection molding machine 10 and the current state of the injection molding machine 10 may be displayed on the display screen of the touch panel. Further, on the display screen of the touch panel, for example, an input operation unit such as a button for accepting an input operation by a user or an input field may be displayed. The touch panel as the operation device 750 detects an input operation on the display screen by the user and outputs a signal corresponding to the input operation to the control device 700. As a result, for example, the user operates the input operation unit provided on the display screen while checking the information displayed on the display screen to set the injection molding machine 10 (including inputting the set value) and the like. It can be carried out. Further, the user can operate the injection molding machine 10 corresponding to the input operation unit by operating the input operation unit provided on the display screen. The operation of the injection molding machine 10 may be, for example, the operation (including stopping) of the mold clamping device 100, the ejector device 200, the injection device 300, the moving device 400, and the like. Further, the operation of the injection molding machine 10 may be switching of a display screen displayed on a touch panel as a display device 760 or the like.

Although the operation device 750 and the display device 760 of the present embodiment have been described as being integrated as a touch panel, they may be provided independently. Further, a plurality of operating devices 750 may be provided. The operating device 750 and the display device 760 are arranged on the operating side (Y-axis negative direction) of the mold clamping device 100 (more specifically, the fixed platen 110).

[Details of mold clamping device]
Next, in addition to FIGS. 1 and 2, the details of the mold clamping device 100 will be described with reference to FIGS. 3 to 6.

3 to 6 are views showing an example of the mold clamping device 100 according to the present embodiment. Specifically, FIGS. 3 to 6 are diagrams showing the operating state of the mold clamping device 100 in each of the mold closing step, the pressurizing step, the mold clamping step, the depressurizing step, and the mold opening step.

In addition, in FIGS. 3 to 6, the drawing of the mold apparatus 800 is omitted.

<Structure of mold clamping device>
As shown in FIGS. 3 to 6, the mold clamping device 100 includes a fixed platen 110, a movable platen 120, a tie bar 140, a hydraulic cylinder 150, a hydraulic circuit 160, and a servomotor 170.

The hydraulic cylinder 150 includes a cylinder body portion 151, a piston portion 152, a rod portion 153, and a cylinder closing portion 154.

The cylinder body portion 151 is a fixing portion of the hydraulic cylinder 150. The cylinder body 151 is connected to the other end of the tie bar 140, one end of which is connected to the fixed platen 110. As a result, the cylinder main body 151 is fixed at a constant distance (interval L) from the fixed platen 110. The cylinder body 151 is provided with a hollow portion in which the front end (end in the negative direction of the X-axis) is opened.

One of the cylinder body 151 and the fixed platen 110 connected via the tie bar 140 is fixed to the mold clamping device frame 910, and the other is movably mounted on the mold clamping device frame 910. As a result, it is possible to allow the tie bar 140 to stretch due to the generation of the mold clamping force.

One end of the piston portion 152 is inserted into the inside (hollow portion) of the cylinder body portion 151, and the other end is fixed to the movable platen 120. As a result, the piston portion 152 can be moved in the front-rear direction (X direction) by the action of the hydraulic oil supplied and discharged to the cylinder main body portion 151, and as a result, the movable platen 120 fixed to one end thereof is moved back and forth. It can be moved in the direction (X direction). Further, the piston portion 152 is provided with a hollow portion that is open to the inside of the cylinder main body portion 151.

One end of the rod portion 153 is fixed to the closed end portion (that is, the end portion in the negative direction of the X axis) of the hollow portion of the cylinder body portion 151, and the other end is inserted into the hollow portion of the piston portion 152. As a result, the rod portion 153 can move the piston portion 152 forward (in the positive direction of the X-axis) by the action of the hydraulic oil supplied to the hollow portion (oil chamber 157 described later) of the piston portion 152. Further, the rod portion 153 is provided with a hole portion extending in the axial direction from the other end side inserted into the hollow portion of the piston portion 152.

The cylinder closing portion 154 closes the open end portion of the cylinder main body portion 151. The cylinder closing portion 154 is provided with a through hole through which the piston portion 152 can penetrate and move forward and backward.

Further, an oil chamber 155 to 157 is provided inside the hydraulic cylinder 150.

The oil chamber 155 is partitioned by the inner wall of the cylinder body 151 and the tip end (one end) of the piston portion 152 at the closed end (end in the negative direction of the X-axis) of the hollow portion of the cylinder body 151. Provided. As a result, the piston portion 152 can exert a mold clamping force on the movable platen 120 by the action of the hydraulic oil supplied to the oil chamber 155. The oil chamber 155 is provided with a port 155P for supplying and discharging hydraulic oil.

The oil chamber 156 is partitioned by an inner wall of the cylinder body 151, an inner wall of the cylinder closing portion 154, and an intermediate portion of the piston portion 152 at the open end (end in the positive direction of the X-axis) of the cylinder body 151. It is provided in. As a result, the piston portion 152 can be retracted (that is, moved in the negative direction of the X-axis) by the action of the hydraulic oil supplied to the oil chamber 156. The oil chamber 156 is provided with a port 156P for supplying and discharging hydraulic oil.

The oil chamber 157 is provided so as to be partitioned by the inner wall of the hollow portion of the piston portion 152 and the tip portion of the rod portion 153. As a result, the piston portion 152 can move forward (that is, move in the positive direction of the X-axis) by the action of the hydraulic oil supplied to the oil chamber 157. The oil chamber 157 communicates with the hole portion of the rod portion 153, and a port 157P for supplying and discharging hydraulic oil to and from the oil chamber 157 is provided at the tip of the hole portion of the rod portion 153.

The hydraulic circuit 160 drives the hydraulic cylinder 150. The hydraulic circuit 160 includes a hydraulic pump 161, a hydraulic tank 162, stop valves 163 to 165, a prefill valve 166, and oil passages OL1 to OL4.

The hydraulic pump 161 supplies the hydraulic oil to the hydraulic cylinder 150 and discharges the hydraulic oil from the hydraulic cylinder 150. The hydraulic pump 161 is driven by a servomotor 170. The hydraulic pump 161 is configured to be capable of discharging hydraulic oil from either one of the ports 161P1 and 161P2 and sucking hydraulic oil from any one of the ports 161P1 and 161P2 by switching the rotation direction of the servomotor 170. Further, the hydraulic pump 161 is connected to the hydraulic tank 162 through the oil passage OL1, and can replenish the hydraulic oil from the hydraulic tank 162 or discharge the hydraulic oil to the hydraulic tank 162.

The port 161P1 is connected to the ports 155P and 157P through the oil passage OL2. Specifically, the oil passage OL2 is branched into the oil passages OL2A and OL2B. The port 161P1 is connected to the port 155P, that is, the oil chamber 155 through the oil passage OL2A, and is connected to the port 157P, that is, the oil chamber 157 through the oil passage OL2B. As a result, the hydraulic pump 161 can supply the hydraulic oil to at least one of the oil chamber 155 and the oil chamber 157 by discharging the hydraulic oil from the port 161P1.

The port 161P2 is connected to the port 156P, that is, the oil chamber 156 through the oil passage OL3. As a result, the hydraulic pump 161 can supply the hydraulic oil to the oil chamber 156 by discharging the hydraulic oil from the port 161P2.

The hydraulic pump 161 and the servomotor 170 may be housed in an integrated housing as an integrated drive unit (hereinafter, “pump unit”), for example (see FIGS. 7 to 10). As a result, the arrangement of the hydraulic pump 161 and the servomotor 170 can be integrated to reduce the size.

The hydraulic pump 161 and the hydraulic tank 162 may be connected by, for example, a steel pipe. That is, the oil passage OL1 may be realized by a steel pipe. Similarly, the hydraulic pump 161 and the cylinder body 151 may be connected by, for example, a steel pipe. That is, the oil passages OL2 (oil passages OL2A, OL2B) and the oil passage OL3 may be realized by steel pipes. As a result, for example, as compared with the case where the oil passages OL1 to OL3 and the like are realized by a rubber pipe or the like, deterioration over time can be suppressed and the maintenance cycle such as replacement or repair can be relatively lengthened.

When at least one of the oil passages OL1 to OL3 is realized by a steel pipe, the cylinder body 151 of the fixed platen 110 and the cylinder body 151 is fixed to the mold clamping device frame 910, and the fixed platen 110 is the mold clamping device frame 910. It may be placed on top so that it can be moved. This is because the fixed platen 110 moves on the mold clamping device frame 910 and can allow the tie bar 140 to stretch due to the mold clamping force as described above. Further, if the cylinder body 151 is moved, it becomes necessary to move the steel pipes corresponding to the oil passages OL1 to OL3 and heavy objects such as the hydraulic pump 161 (pump unit) connected by the steel pipes as a unit, which is wasteful. This is because there is a possibility of consuming a large amount of energy. Further, it is possible to suppress a situation in which a load is accumulated on the steel pipe connecting the cylinder body portion 151 and the hydraulic pump 161 due to the movement of the cylinder body portion 151, and the life of the steel pipe is shortened or damaged. Because it can be done.

The hydraulic tank 162 (an example of a tank) stores hydraulic oil. The hydraulic tank 162 is connected to the hydraulic pump 161 through the oil passage OL1. Further, the hydraulic tank 162 is connected to the port 155P, that is, the oil chamber 155 through the oil passage OL4. As shown in FIGS. 1 and 2, the hydraulic tank 162 is arranged adjacent to the hydraulic cylinder 150 in the width direction (Y-axis direction).

The hydraulic tank 162 may be directly attached to the cylinder body 151 via, for example, the prefill valve 166. That is, the oil passage OL4 is arranged in the housing of the prefill valve 166 integrated with the hydraulic tank 162 and the cylinder main body 151. Further, the hydraulic tank 162 may be connected by, for example, a steel pipe. That is, the oil passage OL4 may be realized by a steel pipe. As a result, for example, as compared with the case where the oil passage OL4 is realized by a rubber pipe or the like, deterioration over time can be suppressed, and the maintenance cycle such as replacement or repair can be relatively lengthened. In the former case, the cylinder body 151, the hydraulic tank 162, and the prefill valve 166 can be integrated. Therefore, the size of the hydraulic circuit 160 and the servomotor 170 can be reduced.

When the hydraulic tank 162 is directly attached to the cylinder body 151 via the prefill valve 166 or when the oil passage OL4 is realized by a steel pipe, the cylinder body of the fixed platen 110 and the cylinder body 151 is the same as described above. 151 may be fixed to the mold clamping device frame 910, and the fixed platen 110 may be movably mounted on the mold clamping device frame 910. As a result, the same actions and effects as described above are obtained.

The stop valve 163 is provided in the oil passage OL2A. The stop valve 163 switches between the communication state and the shutoff state of the oil passage OL2A under the control of the control device 700. Thereby, for example, the stop valve 163 can supply the hydraulic oil discharged from the port 161P1 of the hydraulic pump 161 to only the oil chamber 157 through the oil passage OL2B by shutting off the oil passage OL2A.

The stop valve 164 is provided in the oil passage OL2B. The stop valve 164 switches between a communication state and a cutoff state of the oil passage OL2B under the control of the control device 700. Thereby, for example, the stop valve 164 can supply the hydraulic oil discharged from the port 161P1 of the hydraulic pump 161 to only the oil chamber 155 through the oil passage OL2A by shutting off the oil passage OL2B. Further, the stop valve 164 can hold the hydraulic oil in the oil chamber 157 by shutting off the oil passage OL2B, for example.

The stop valve 165 is provided in the oil passage OL3. The stop valve 165 switches between a communication state and a cutoff state of the oil passage OL3 under the control of the control device 700. As a result, the stop valve 165 can, for example, shut off the oil passage OL3 so that the hydraulic oil sucked from the port 161P1 into the hydraulic pump 161 is discharged to the hydraulic tank 162 without being discharged from the port 161P2. Can be done.

Hereinafter, the description will proceed on the premise that the stop valves 163 to 165 are normally opened (that is, they are normally open type) and are closed in response to a control command from the control device 700.

The prefill valve 166 is provided in the oil passage OL4. The prefill valve 166 is normally closed (ie, normally closed) and is opened in response to a pilot pressure supplied from a pilot line (not shown) branching from the oil passage OL3.

The servomotor 170 operates under the control of the control device 700. As a result, the control device 700 can control the operation of the hydraulic pump 161 by controlling the servomotor 170.

The control device 700 controls the flow of hydraulic oil in the hydraulic circuit 160 by controlling the hydraulic pump 161 (servomotor 170) and the stop valves 163 to 165, and the mold closing process, boosting process, and mold by the mold clamping device 100. Realize the tightening process, depressurization process, and mold opening process.

As described above, in the present embodiment, the mold clamping device 100 is hydraulically driven by the hydraulic cylinder 150. Specifically, the hydraulic cylinder 150 drives the movable platen 120 by a so-called direct pressure type. As a result, the mold clamping device 100 can have a shorter dimension in the X direction than in the case of the so-called toggle type. Therefore, the size of the injection molding machine 10 can be reduced.

Further, in the present embodiment, the hydraulic circuit 160 that hydraulically drives the mold clamping device 100 (hydraulic cylinder 150) is composed of a closed circuit.

If the hydraulic circuit 160 is an open circuit, the hydraulic circuit 160 needs to be provided with a direction switching valve for switching the direction in which the hydraulic oil flows. Further, the hydraulic circuit 160 needs to be provided with a hydraulic tank 162 having a relatively large capacity. This is because it is necessary to supply all the hydraulic oil of the hydraulic circuit 160 from the hydraulic tank 162. Therefore, the size of the hydraulic circuit 160 becomes large, and there is a possibility that the components cannot be arranged only in a place near the hydraulic cylinder 150 to be driven. Therefore, for example, it may be necessary to arrange a hydraulic tank or the like in the space under the mold device 800. As a result, in the space under the mold device 800, it becomes impossible to arrange a transport device or the like for receiving the molded product projected from the mold device 800 by the ejector device 200 and transporting the molded product to another place, and the user. There is a possibility that the convenience of

On the other hand, in the present embodiment, the hydraulic circuit 160 is configured as a closed circuit, so that the size of the hydraulic circuit 160 can be reduced and its components can be concentrated in a place adjacent to the hydraulic cylinder 150. Specifically, as described above, the hydraulic tank 162 can be arranged adjacent to the hydraulic cylinder 150 (see FIGS. 1 and 2). Further, as described later, a pump unit composed of a hydraulic pump 161 and a servomotor 170 or the like can be arranged adjacent to the hydraulic cylinder 150. Therefore, for example, it is not necessary to arrange the components of the hydraulic circuit 160 in the space under the mold device 800, and the convenience of the user can be improved.

<Operation of mold clamping device>
In the mold closing step, the control device 700 outputs a control command to the stop valve 163 to close the stop valve 163. As a result, the oil passage OL2A of the oil passages OL2A and OL2B is shut off.

Further, the control device 700 outputs a control command to the servomotor 170 and operates the hydraulic pump 161 so as to discharge hydraulic oil from the port 161P1. As a result, as shown in FIG. 3, the hydraulic pump 161 sucks the hydraulic oil from the oil passage OL3, discharges the hydraulic oil from the oil chamber 156, discharges the hydraulic oil to the oil passage OL2B, and passes through the oil passage OL2B. Hydraulic oil can be supplied to the oil chamber 157. Therefore, the hydraulic cylinder 150 extends and the piston portion 152 (movable platen 120) moves from the mold closing start position to the mold closing completion position in such a manner that the piston portion 152 protrudes forward from the hollow portion of the cylinder body portion 151.

In the boosting step and the mold clamping step, the control device 700 outputs a control command to the stop valve 164 to close the stop valve 164. As a result, the oil passage OL2B of the oil passages OL2A and OL2B is closed, and the hydraulic oil in the oil chamber 157 is held.

Further, the control device 700 outputs a control command to the servomotor 170 and operates the hydraulic pump 161 so as to discharge hydraulic oil from the port 161P1. As a result, as shown in FIG. 4, the hydraulic pump 161 can discharge the hydraulic oil to the oil passage OL2A and supply the hydraulic oil to the oil chamber 155 through the oil passage OL2A.

Further, at the start of the boosting process, a predetermined pilot pressure acts on the prefill valve 166 from the above-mentioned pilot line by the action of the hydraulic oil flowing through the oil passage OL3 in the mold clamping process, and the prefill valve 166 is opened. ing. Further, at the start of the pressurizing step, the oil chamber 155 is in a negative pressure state. Therefore, as shown in FIG. 4, hydraulic oil is supplied from the hydraulic tank 162 to the oil chamber 155 through the oil passage OL4.

Due to the action of the hydraulic oil supplied to the oil chamber 155, the piston portion 152 protrudes further forward from the hollow portion of the cylinder body portion 151, and the hydraulic cylinder 150 further extends. Therefore, the piston portion 152 (movable platen 120) further moves from the mold closing completion position to the mold clamping position to generate a mold clamping force and is maintained at the mold clamping position.

In the depressurization step, the control device 700 outputs a control command to the stop valves 164 and 165 to close the stop valves 164 and 165. As a result, the oil passage OL2B of the oil passages OL2A and OL2B is closed, and the hydraulic oil in the oil chamber 157 is held. Further, the oil passage OL3 is shut off so that the hydraulic oil does not flow into the oil chamber 156.

Further, the control device 700 outputs a control command to the servomotor 170 and operates the hydraulic pump 161 so as to suck the hydraulic oil from the port 161P1. As a result, as shown in FIG. 5, the hydraulic pump 161 sucks the hydraulic oil from the oil passage OL2A, discharges the hydraulic oil from the oil chamber 155, and discharges the hydraulic oil to the hydraulic tank 162 through the oil passage OL1 ( Discharge. Therefore, the mold clamping force generated by the action of the hydraulic oil in the oil chamber 155 is gradually reduced, and the piston portion 152 (movable platen 120) returns from the mold clamping position to the mold opening start position (mold closing completion position).

In the mold opening process, the control device 700 outputs a control command to the stop valve 163 and closes the stop valve 163. As a result, the oil passage OL2A of the oil passages OL2A and OL2B is shut off.

Further, the control device 700 outputs a control command to the hydraulic pump 161 and operates the hydraulic pump 161 so as to suck the hydraulic oil from the port 161P1 and discharge the hydraulic oil from the port 161P2. As a result, as shown in FIG. 6, the hydraulic pump 161 sucks the hydraulic oil from the oil passage OL2B, discharges the hydraulic oil from the oil chamber 157, and discharges the hydraulic oil to the oil passage OL3 to the oil chamber 156. Supply hydraulic oil. Further, the hydraulic pump 161 replenishes the hydraulic oil from the hydraulic tank 162 through the oil passage OL1. Therefore, in a mode in which the piston portion 152 is inserted into the hollow portion of the cylinder body portion 151, the hydraulic cylinder 150 contracts, and the piston portion 152 (movable platen 120) moves from the mold opening start position to the mold opening completion position.

Further, due to the action of the hydraulic oil flowing through the oil passage OL3, a predetermined pilot pressure acts on the prefill valve 166 from the above-mentioned pilot line, and the prefill valve 166 is opened. Therefore, as the hydraulic cylinder 150 contracts, the hydraulic oil remaining in the oil chamber 155 is discharged to the hydraulic tank 162 through the oil passage OL4.

As described above, in the present embodiment, the mold clamping device 100 is hydraulically driven by the hydraulic cylinder 150 for all operations related to the mold closing step, the pressurizing step, the mold clamping step, the depressurizing step, and the mold opening step.

For example, when the operations related to the boosting process, the mold clamping process, and the depressurizing process are hydraulically driven, and the operations related to the mold opening process and the mold closing process are electrically driven, there is a concern that the configuration of the mold clamping device 100 may be complicated. NS.

On the other hand, in the present embodiment, the mold clamping device 100 can hydraulically drive the operations related to all the processes by the hydraulic cylinder 150 to simplify the components. Therefore, the size of the mold clamping device 100 can be reduced.

[Details of ejector device]
Next, the details of the ejector device 200 will be described with reference to FIG. 7.

FIG. 7 is a cross-sectional view showing an example of the ejector device 200 according to the present embodiment. Specifically, FIG. 7 is a diagram showing a state in which the ejector rod 210 is retracted into the movable platen 120.

The ejector device 200 includes an ejector rod 210, a ball screw shaft 220, a ball screw nut 230, a bearing 240, a driven pulley 250, a timing belt 260, a drive pulley (not shown), and an ejector motor (not shown). It has a pulley housing 270 and a pulley housing 270.

The ejector rod 210 is provided so as to be movable back and forth from the hole 121 of the movable platen 120. When the ejector rod 210 advances, the front end of the ejector rod 210 comes into contact with the movable member 830 (see FIG. 1), and the movable member can be advanced.

At the rear end of the ejector rod 210, a connecting portion 211 for detachably connecting to the ball screw shaft 220 is provided. For example, a female screw is formed in the joint portion 211 and is screwed with a male screw formed in the ball screw shaft 220. As a result, the ejector rod 210 is coupled to the ball screw shaft 220.

Further, a connecting portion 212 for connecting a shaft member (not shown) used when extending the ejector rod 210 may be provided at the front end of the ejector rod 210. For example, a female screw may be formed on the joint portion 212 and may be screwed with a male screw formed on the shaft member. As a result, the length of the ejector rod 210 can be extended by connecting the shaft member to the ejector rod 210.

The ball screw shaft 220 is screwed with the ball screw nut 230. Further, the ball screw shaft 220 is stopped by the ejector crosshead 224. As a result, the ball screw shaft 220 and the ball screw nut 230 form a motion conversion mechanism that converts the rotational motion of the ball screw nut 230 into a linear motion of the ball screw shaft 220. That is, the rotation of the ball screw nut 230 causes the ball screw shaft 220 to move in the axial direction.

The bearing 240 rotatably supports the ball screw nut 230. Here, the accommodating portion 158 is formed on the tip end side (front side of the oil chamber 157) of the piston portion 152. The outer ring of the bearing 240 is fitted to the accommodating portion 158 and is prevented from coming off by the spacer 241. Further, the inner ring of the bearing 240 is fitted with the ball screw nut 230 and is prevented from coming off by the lock nut 242 screwed with the ball screw nut 230. As a result, the axial movement of the ball screw nut 230 is restricted.

In this way, at least a part of the ejector device 200 is arranged in the accommodating portion 158 formed on the tip end side of the piston portion 152. Specifically, a motion conversion mechanism (ball screw shaft 220, ball screw nut 230) and a bearing 240 are arranged in the accommodating portion 158. The rear side of the motion conversion mechanism (ball screw shaft 220, ball screw nut 230) is arranged in the accommodating portion 158, and the front side of the motion conversion mechanism (ball screw shaft 220, ball screw nut 230) is the tip of the piston portion 152. It may be placed before.

The driven pulley 250 is fixed to the front side of the ball screw nut 230 with a bolt 255. Further, the drive pulley (not shown) is fixed to the rotating shaft of the ejector motor (not shown). The drive pulley and the driven pulley 250 are connected by a timing belt 260.

With such a configuration, by operating the ejector motor, the ball screw nut 230 rotatably supported by the bearing 240 rotates via the drive pulley, the timing belt 260, and the driven pulley 250. The rotary motion of the ball screw nut 230 is converted into a linear motion of the ball screw shaft 220 screwed with the ball screw nut 230. The ejector rod 210 moves back and forth due to the linear motion of the ball screw shaft 220.

The pulley housing 270 has a substantially cylindrical shape, is arranged between the piston portion 152 and the movable platen 120, and is fixed to the piston portion 152 and the movable platen 120. Specifically, a bolt hole (not shown) is formed on the tip surface of the piston portion 152. The rear side of the spacer 241 is fitted to the accommodating portion 158 of the piston portion 152, and the front side of the spacer 241 is fitted to the pulley housing 270 to be coaxially positioned. Then, the spacer 241 is sandwiched between the front end surface of the piston portion 152 and the rear surface of the pulley housing 270, and is fixed by bolts 272 from the inside of the pulley housing 270. Further, the movable platen 120 and the pulley housing 270 are fitted to each other so that they are coaxially positioned. Then, the movable platen 120 and the pulley housing 270 are fixed by bolts (not shown). With such a configuration, the piston portion 152 moves in the front-rear direction (X direction), so that the pulley housing 270 and the movable platen 120 both move in the front-rear direction (X direction). The nut 141 adjusts the distance between the fixed platen 110 connected by the tie bar 140 and the cylinder body 151 of the hydraulic cylinder 150.

The substantially cylindrical shape of the pulley housing 270 is closed by the movable platen 120 on the front side and by the piston portion 152 on the rear side, so that the accommodating portion 271 is formed inside the pulley housing 270. A driven pulley 250 is arranged in the accommodating portion 271 of the pulley housing 270. Further, the accommodating portion 271 of the pulley housing 270, the accommodating portion 158 of the piston portion 152, and the hole portion 121 of the movable platen 120 communicate with each other. The movable platen 120 may be provided with a digging portion.

Further, the drive pulley (not shown) and the ejector motor (not shown) may be arranged outside the pulley housing 270. For example, the ejector motor may be fixed to the side surface (including the upper surface and the lower surface) of the movable platen 120. The timing belt 260 passes through an opening (not shown) provided in the pulley housing 270, and is a driven pulley 250 arranged inside the pulley housing 270 and a drive pulley arranged outside the pulley housing 270 (not shown). It is hung between the belt and the belt.

Here, the axial length of the piston portion 152 is determined based on the movable range (platen stroke) of the movable platen 120 when the mold is opened and closed. Further, a hollow portion (oil chamber 157) is formed from the rear end side of the piston portion 152. Therefore, the tip end side of the piston portion 152 has a region in which the hollow portion (oil chamber 157) is not formed. Further, the axial lengths of the ball screw shaft 220 and the ball screw nut 230 are determined based on the movable range (ejector stroke) of the ejector rod 210. In the ejector device 200 of the present embodiment, an accommodating portion 158 is provided on the tip end side of the piston portion 152 to accommodate at least a part of the constituent articles of the ejector device 200. With such a configuration, the total length of the mold clamping device 100 can be shortened while ensuring the platen stroke and the ejector stroke. That is, it can be a compact injection molding machine 10.

In the ejector device 200 shown in FIG. 7, the ball screw nut 230 rotates and the ball screw shaft 220 moves in the front-rear direction, but the present invention is not limited to this. The ball screw nut may be fixed to the accommodating portion 158 of the piston portion 152, and the ball screw shaft may rotate. Even in such a configuration, the total length of the mold clamping device 100 can be shortened while securing the platen stroke and the ejector stroke by accommodating at least a part of the constituent articles of the ejector device 200. That is, it can be a compact injection molding machine 10.

Further, in the ejector device 200 of the present embodiment, it is preferable that the bearing 240 is attached to the ball screw nut 230. That is, in the motion conversion mechanism, the ball screw nut 230 rotates, and the ball screw shaft 220 advances and retreats in the axial direction. Here, in a configuration in which the ball screw nut is fixed to the accommodating portion 158 of the piston portion 152 and the ball screw shaft rotates, a mechanism for preventing the transmission of rotation between the rotating ball screw shaft and the ejector rod (for example). , Thrust bearing) must be provided. Therefore, the total length of the ejector device 200 is extended. On the other hand, in the ejector device 200 of the present embodiment, the ejector rod 210 can be directly attached to the ball screw shaft 220 that advances and retreats in the axial direction. As a result, the total length of the mold clamping device 100 can be shortened. That is, it can be a compact injection molding machine 10.

Further, in the ejector device 200 of the present embodiment, the drive pulley (not shown) and the ejector motor (not shown) are preferably arranged radially outside the piston portion 152. In other words, the shafts of the ejector rod 210 and the ball screw shaft 220 are arranged coaxially with the shaft of the piston portion 152, and the rotation shaft of the ejector motor (not shown) is arranged at a position different from the shaft of the piston portion 152. Has been done. As a result, the total length of the mold clamping device 100 can be shortened. That is, it can be a compact injection molding machine 10.

Further, in the ejector device 200 of the present embodiment, the ejector rod 210 is operated by an ejector motor (not shown). Therefore, the position and operating speed of the ejector rod 210 can be measured by detecting the rotation speed of the ejector motor (not shown) with the ejector motor encoder (not shown). In other words, the control device 700 can easily control the position and speed of the ejector rod 210 by controlling the ejector motor (not shown).

Further, a supply unit 221 for supplying a lubricant such as grease is provided at the tip of the ball screw shaft 220. The supply unit 221 is formed of, for example, a nipple having a check valve. Further, the ball screw shaft 220 has a supply path 222 that communicates with the supply unit 221 and extends axially from the tip of the ball screw shaft 220, and a supply path 223 that extends radially from the supply path 222.

Further, the piston portion 152 is formed with a discharge path 159 that communicates the accommodating portion 158 with the outside. Further, a pipe 159a is connected to the discharge path 159.

Here, when supplying the lubricant to the motion conversion mechanism (ball screw shaft 220, ball screw nut 230), the ejector rod 210 is removed from the ball screw shaft 220, and the lubricant supply device (not shown) is supplied to the supply unit 221. For example, a grease gun.) Is connected to supply the lubricant. The lubricant supplied from the supply unit 221 is supplied to the transfer surface between the ball screw shaft 220 and the ball screw nut 230 via the supply paths 222 and 223. Further, the excess lubricant is discharged from the accommodating portion 158 through the gap between the ball screw shaft 220 and the ball screw nut 230 to the accommodating portion 158, and further discharged from the accommodating portion 158 through the discharge path 159 and the pipe 159a to the outside. ..

Here, it is difficult to supply the lubricant from the side of the piston portion 152 and the ball screw nut 230 to the transfer surface between the ball screw shaft 220 and the ball screw nut 230 because the ball screw nut 230 is configured to rotate. .. Further, in the configuration in which the lubricant is supplied to the accommodating portion 158 of the piston portion 152 to lubricate the ball screw shaft 220 and the ball screw nut 230, the amount of lubricant used increases.

On the other hand, in the ejector device 200 of the present embodiment, by supplying the lubricant from the ball screw shaft 220, it can be directly supplied to the transfer surface between the ball screw shaft 220 and the ball screw nut 230. As a result, the amount of lubricant can be supplied as much as necessary, so that the amount of lubricant can be reduced.

The hole of the coupling portion 211 of the ejector rod 210 and the hole of the coupling portion 212 may communicate with each other. According to such a configuration, the lubricant can be supplied from the supply unit 221 without removing the ejector rod 210.

Further, although the supply unit 221 has been described as being formed at the tip of the ball screw shaft 220, the present invention is not limited to this. For example, the supply unit 221 may be formed on the cylindrical surface on the front side of the ball screw shaft 220. In this configuration, the ejector motor (not shown) is driven to advance the ball screw shaft 220 so that the front side of the ball screw shaft 220 protrudes from the movable platen 120. As a result, the lubricant can be supplied to the supply portion 221 of the ball screw shaft 220 protruding from the hole portion 121 of the movable platen 120.

Further, the pulley housing 270 may be provided with an opening (not shown) for work, and the lubricant may be supplied to the supply portion 221 formed on the cylindrical surface on the front side of the ball screw shaft 220. In this configuration, the ball screw shaft 220 and the ball screw nut 230 can be lubricated without removing the mold device 800 from the mold clamping device 100.

FIG. 8 is a partially enlarged cross-sectional view showing another example of the ejector device 200 according to the present embodiment.

The pulley housing 270 is provided with a supply unit 273 such as a nipple. Further, the accommodating portion 271 of the pulley housing 270 is provided with a flexible hose 274 that connects the supply portion 273 of the pulley housing 270 and the supply portion 228 formed on the cylindrical surface on the front side of the ball screw shaft 220. There is. As a result, the lubricant is supplied from the supply unit 273 of the pulley housing 270 to the supply unit 228 of the ball screw shaft 220 via the hose 274. The lubricant supplied from the supply unit 228 is supplied to the transfer surface between the ball screw shaft 220 and the ball screw nut 230 via the supply paths 222 and 223.

According to the ejector device 200 shown in FIG. 8, the supply unit 273 can be connected to an automatic supply device (not shown) to automatically supply the lubricant.

Further, a partition 226 for preventing contact between the hose 274 and the ball screw nut 230 and the driven pulley 250, which are rotating bodies, may be provided. The partition 226 may be sandwiched between the flange portion 225 of the ball screw shaft 220 and the lock nut 227 screwed with the ball screw shaft 220, and may be integrally fixed to the ball screw shaft 220.

10 Injection molding machine 100 Mold clamping device 110 Fixed platen 120 Movable platen 121 Hole 140 Tie bar 150 Hydraulic cylinder (hydraulic cylinder)
151 Cylinder body 152 Piston 153 Rod 154 Cylinder closure 155-157 Oil chamber 158 Storage 159 Discharge path 160 Hydraulic circuit 161 Hydraulic pump 162 Hydraulic tank (tank)
163 to 165 Stop valve 166 Prefill valve 170 Servo motor 200 Ejector device 210 Ejector rod 211 Coupling part 212 Coupling part 220 Ball screw shaft 221 Supply part 222 Supply path 223 Supply path 224 Ejector cross head 225 Flute part 226 Partition 227 Locknut 228 Supply Part 230 Ball screw nut 240 Bearing 241 Seat 242 Locknut 250 Driven pulley 255 Bolt 260 Timing belt 270 Pulley housing 271 Accommodating part 272 Bolt 273 Supply part 274 Hose 300 Injection device 400 Moving device 700 Control device 701 CPU
702 Storage medium 703 Input interface 704 Output interface 750 Operation device 760 Display device

Claims (8)

A fixed platen to which a fixed mold can be attached,
A movable platen to which a movable mold can be attached,
A hydraulic cylinder that advances and retreats the movable platen,
Equipped with an ejector device that moves the ejector rod forward and backward,
The piston portion of the hydraulic cylinder has an accommodating portion and has an accommodating portion.
At least a part of the components of the ejector device are arranged in the accommodating portion.
Injection molding machine. The ejector device is
It has a screw shaft and a screw nut that screwes into the screw shaft.
The screw nut is rotatably supported by the accommodating portion of the piston portion.
The screw shaft moves forward and backward as the screw nut rotates.
The injection molding machine according to claim 1. The ejector rod is attached to the screw shaft.
The injection molding machine according to claim 2. The screw shaft has a supply path for supplying a lubricant between the screw shaft and the screw nut.
The injection molding machine according to claim 2 or 3. The screw shaft has a supply portion communicating with the supply path at the tip of the screw shaft.
The injection molding machine according to claim 4. The screw shaft has a supply portion on the side surface of the screw shaft.
The injection molding machine according to claim 4. A housing for accommodating the screw nut and the pulley to be fixed is provided.
A supply unit provided in the housing and
A flexible hose for connecting the supply unit and the supply path of the screw shaft is provided.
The injection molding machine according to claim 4. It has a partition that separates the flexible hose from the pulley.
The injection molding machine according to claim 7.

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