Injection molding machine

Abstract

An injection molding machine is provided with: a nozzle that injects a molding material into a mold device; a flow path opening and closing mechanism that opens and closes a flow path of the molding material in the nozzle; a cylinder body in which the nozzle is provided at a front end portion; a screw that is rotatably and linearly movably arranged inside the cylinder body; a drive source that drives the screw; and a control device that controls the flow path opening and closing mechanism and the drive source, the flow path opening and closing mechanism having a spool that moves between an open position that opens the flow path and a closed position that closes the flow path, the control device releasing fixation of the spool in the closed position after starting a metering process of reserving the molding material in a front portion of the cylinder body and before starting a filling process of filling the molding material reserved in the front portion of the cylinder body into an inside of the mold device, thereby performing control that allows the spool to move to the open position by a pressure of the molding material reserved in an inside of the nozzle.

Description

[0001] This application is a divisional application filed on January 31, 2018, with application number 201880009377.X and invention title "Injection Molding Machine". Technical Field

[0002] This invention relates to an injection molding machine. Background Technology

[0003] To prevent leakage of molten resin in the cylinder when the mold is opened, the injection molding machine described in Patent Document 1 has a flow-stopping nozzle at the front of the cylinder that can be opened and closed by a needle valve. The needle valve can be driven by a linear cam, a direct-acting type, or a lever type. All of these methods involve moving the needle valve back and forth, utilizing the force of an actuator when closing the needle valve and the resin pressure generated during resin injection when opening the needle valve (see paragraph 0004 of Patent Document 1).

[0004] Previous technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2002-292683 Summary of the Invention

[0007] The technical problem to be solved by the invention

[0008] The nozzle contains a flow path for molding materials such as resin, and is equipped with a valve core that moves between an open position (opening the flow path) and a closed position (closing the flow path). The valve core can move in the direction of the nozzle axis or in a direction orthogonal to the nozzle axis.

[0009] Previously, when the valve core moved from the closed position to the open position, it would utilize the pressure of the molding material generated during the filling process. Because the pressure of the molding material generated during the filling process was large, the valve core moved too forcefully, which sometimes caused the valve core or the valve core moving mechanism that moved the valve core to be damaged due to the impact.

[0010] The present invention was made in view of the above-mentioned problems, and its object is to provide an injection molding machine that can reduce the impact caused by the movement of the valve core in the flow path of the molding material in the opening and closing nozzle.

[0011] means for solving technical problems

[0012] To address the aforementioned issues, according to one aspect of the present invention, an injection molding machine is provided, comprising:

[0013] The nozzle injects molding material into the mold assembly;

[0014] A flow path opening and closing mechanism for opening and closing the flow path of the molding material in the nozzle;

[0015] The cylinder body has the nozzle provided at its front end;

[0016] The screw is configured inside the cylinder to rotate freely and move forward and backward freely;

[0017] A drive source drives the screw; and

[0018] The control device controls the flow path opening and closing mechanism and the drive source.

[0019] The flow path opening and closing mechanism includes: a valve core that moves between an open position (opening the flow path) and a closed position (closing the flow path); and a valve core moving mechanism that performs actions to move the valve core from the open position to the closed position and fix the valve core in the closed position, and to release the valve core from the closed position so that the valve core moves to the open position by the pressure of the molding material stored inside the nozzle.

[0020] After the metering process of storing the molding material in the front of the cylinder begins and before the filling process of filling the molding material stored in the front of the cylinder into the mold device begins, the control device releases the valve core located in the closed position, thereby performing control to move the valve core to the open position by the pressure of the molding material stored inside the nozzle.

[0021] Invention Effects

[0022] According to one aspect of the present invention, an injection molding machine is provided that can reduce the impact caused by the movement of the valve core in the flow path of the molding material in the opening and closing nozzle. Attached Figure Description

[0023] Figure 1 This is a diagram showing the state of an injection molding machine at the end of mold opening according to one embodiment.

[0024] Figure 2 This is a diagram showing the state of the injection molding machine during mold closing according to one embodiment.

[0025] Figure 3 It means by making Figure 5 The swing lever shown swings in the first direction, causing the valve core to move from... Figure 5 The diagram shows the state of the open position moving to the closed position.

[0026] Figure 4 It means to make Figure 3 The diagram shows the state of the swing rod swinging in the second direction.

[0027] Figure 5It means that the pressure of the molding material is used to make Figure 4 The diagram shows the state of the valve core moving from the closed position to the closed position.

[0028] Figure 6 This is a diagram illustrating the timing of the processes performed by the injection device according to one embodiment, the movement of the swing rod, and the movement of the valve core.

[0029] Figure 7 This is a graph showing the time-varying pressure detected by a pressure detector according to one embodiment. Detailed Implementation

[0030] Hereinafter, the methods for implementing the present invention will be described with reference to the accompanying drawings, in which the same or corresponding structures are labeled with the same or corresponding symbols and the description is omitted.

[0031] (Injection molding machine)

[0032] Figure 1 This is a diagram showing the state of an injection molding machine at the end of mold opening according to one embodiment. Figure 2 This is a diagram showing the state of the injection molding machine during mold closing according to one embodiment. Figures 1-2 In this context, the X, Y, and Z directions are mutually perpendicular. The X and Y directions represent the horizontal direction, and the Z direction represents the vertical direction. When the mold clamping device 100 is horizontal, the X direction is the mold opening and closing direction, and the Y direction is the width direction of the injection molding machine. For example... Figures 1-2 As shown, the injection molding machine includes a mold clamping device 100, an ejection device 200, an injection device 300, a moving device 400, a control device 700, and a frame Fr. The components of the injection molding machine will be described below.

[0033] (Mold closing device)

[0034] In the description of the mold closing device 100, the direction of movement of the movable pressure plate 120 during mold closing is described as follows: Figure 1 and Figure 2 The right side is set as the front, and the moving direction of the movable pressure plate 120 during mold opening is set as follows: Figure 1 and Figure 2 The middle (left side) is used for explanation.

[0035] The mold closing device 100 performs mold closing, mold fitting, and mold opening of the mold device 10. The mold closing device 100 is, for example, horizontal, and the mold opening and closing direction is horizontal. The mold closing device 100 includes a fixed pressure plate 110, a movable pressure plate 120, a toggle seat 130, a connecting rod 140, a toggle mechanism 150, a mold closing motor 160, a motion conversion mechanism 170, and a mold thickness adjustment mechanism 180.

[0036] The fixed pressure plate 110 is fixed to the frame Fr. A fixed mold 11 is installed on the surface of the fixed pressure plate 110 that faces the movable pressure plate 120.

[0037] The movable pressure plate 120 is designed to move freely relative to the frame Fr in the mold opening and closing direction. A guide member 101 for guiding the movable pressure plate 120 is laid on the frame Fr. A movable mold 12 is mounted on the surface of the movable pressure plate 120 opposite to the fixed pressure plate 110.

[0038] Mold closing, mold assembly, and mold opening are achieved by moving the movable pressure plate 120 forward and backward relative to the fixed pressure plate 110. The mold assembly 10 consists of a fixed mold 11 and a movable mold 12.

[0039] The toggle seat 130 is connected to the fixed pressure plate 110 with a gap between them and is mounted on the frame Fr in a direction that allows free movement in the mold opening and closing direction. Alternatively, the toggle seat 130 may be configured to move freely along a guide laid on the frame Fr. The guide of the toggle seat 130 may be shared with the guide 101 of the movable pressure plate 120.

[0040] In addition, in this embodiment, the fixed pressure plate 110 is fixed to the frame Fr, and the toggle seat 130 is configured to move freely relative to the frame Fr in the mold opening and closing direction. However, the toggle seat 130 can also be fixed to the frame Fr, and the fixed pressure plate 110 can be configured to move freely relative to the frame Fr in the mold opening and closing direction.

[0041] Connecting rods 140 connect the fixed pressure plate 110 and the toggle seat 130 at a distance L in the mold opening and closing direction. Multiple connecting rods 140 (e.g., four) can be used. Each connecting rod 140 is set parallel to the mold opening and closing direction and elongates according to the clamping force. A connecting rod strain detector 141 for detecting the strain of the connecting rod 140 can be installed on at least one connecting rod 140. The connecting rod strain detector 141 sends a signal indicating its detection result to the control device 700. The detection result of the connecting rod strain detector 141 is used for detecting the clamping force, etc.

[0042] In this embodiment, a connecting rod strain gauge 141 is used as the mold clamping force detector, but the present invention is not limited to this. The mold clamping force detector is not limited to a strain gauge and can also be piezoelectric, capacitive, hydraulic, electromagnetic, etc., and its installation position is not limited to the connecting rod 140.

[0043] A toggle mechanism 150 is disposed between a movable pressure plate 120 and a toggle seat 130, and allows the movable pressure plate 120 to move relative to the toggle seat 130 in the mold opening and closing direction. The toggle mechanism 150 consists of a crosshead 151, a pair of linkages, etc. Each linkage has a first linkage 152 and a second linkage 153 connected by pins to be freely flexible. The first linkage 152 is mounted to the movable pressure plate 120 by pins to be freely oscillating, and the second linkage 153 is mounted to the toggle seat 130 by pins to be freely oscillating. The second linkage 153 is mounted to the crosshead 151 via a third linkage 154. When the crosshead 151 moves forward or backward relative to the toggle seat 130, the first linkage 152 and the second linkage 153 flex and extend, and the movable pressure plate 120 moves forward or backward relative to the toggle seat 130.

[0044] Furthermore, the structure of the toggle mechanism 150 is not limited to Figure 1 and Figure 2 The structure shown. For example, in Figure 1 and Figure 2 In this configuration, each link group has 5 nodes, but it can also have 4 nodes, and one end of the third link 154 can also be connected to the nodes of the first link 152 and the second link 153.

[0045] The clamping motor 160 is mounted on the toggle seat 130 and operates the toggle mechanism 150. The clamping motor 160 moves the crosshead 151 forward and backward relative to the toggle seat 130, thereby extending and retracting the first link 152 and the second link 153, and moving the movable pressure plate 120 forward and backward relative to the toggle seat 130. The clamping motor 160 is directly connected to the motion conversion mechanism 170, but it can also be connected to the motion conversion mechanism 170 via a belt or pulley.

[0046] The motion conversion mechanism 170 converts the rotary motion of the clamping motor 160 into the linear motion of the crosshead 151. The motion conversion mechanism 170 includes a threaded shaft 171 and a nut 172 that engages with the threaded shaft 171. Ball bearings or rollers can be clamped between the threaded shaft 171 and the nut 172.

[0047] Under the control of the control device 700, the mold closing device 100 performs the mold closing process, the mold closing process, and the mold opening process.

[0048] In the mold closing process, the mold closing motor 160 is driven to advance the crosshead 151 at a set speed to the mold closing end position, thereby advancing the movable pressure plate 120 and bringing the movable mold 12 into contact with the fixed mold 11. The position or speed of the crosshead 151 is detected, for example, using a mold closing motor encoder 161. The mold closing motor encoder 161 detects the rotation of the mold closing motor 160 and sends a signal indicating its detection result to the control device 700. Furthermore, the crosshead position detector for detecting the position of the crosshead 151 and the crosshead speed detector for detecting the speed of the crosshead 151 are not limited to the mold closing motor encoder 161; general detectors can be used. Similarly, the movable pressure plate position detector for detecting the position of the movable pressure plate 120 and the movable pressure plate speed detector for detecting the speed of the movable pressure plate 120 are not limited to the mold closing motor encoder 161; general detectors can be used.

[0049] In the mold closing process, the mold closing motor 160 is further driven to advance the crosshead 151 from the mold closing end position to the mold closing position, thereby generating a mold closing force. During mold closing, a cavity space 14 is formed between the movable mold 12 and the fixed mold 11 (see reference). Figure 2 The injection device 300 fills the cavity space 14 with liquid molding material. The filled molding material solidifies, thereby obtaining a molded article. There can be multiple cavity spaces 14, and multiple molded articles can be obtained simultaneously.

[0050] During the mold opening process, the drive mold closing motor 160 causes the crosshead 151 to retract at a set speed to the mold opening end position, thereby causing the movable pressure plate 120 to retract, thus separating the movable mold 12 from the fixed mold 11. Afterwards, the ejection device 200 ejects the molded product from the movable mold 12.

[0051] The setting conditions in the mold closing and mold closing processes are uniformly set as a series of setting conditions. For example, the speed or position of the crosshead 151 in the mold closing and mold closing processes (including the mold closing start position, speed switching position, mold closing end position, and mold closing position) and the mold closing force are uniformly set as a series of setting conditions. The mold closing start position, speed switching position, mold closing end position, and mold closing position are arranged sequentially from back to front to represent the start or end point of the speed setting segment. The speed is set for each segment. There can be one or more speed switching positions. Alternatively, no speed switching position can be set. It is also possible to set only either the mold closing position or the mold closing force.

[0052] The setting conditions in the mold opening process are also set in the same way. For example, the speed or position of the crosshead 151 in the mold opening process (including the mold opening start position, speed switching position, and mold opening end position) is set uniformly as a series of setting conditions. The mold opening start position, speed switching position, and mold opening end position are arranged sequentially from front to back to indicate the start or end point of the speed setting segment. A speed is set for each segment. There can be one or more speed switching positions. Alternatively, no speed switching position may be set. The mold opening start position and the mold closing position can be the same position. Furthermore, the mold opening end position and the mold closing start position can also be the same position.

[0053] Alternatively, the speed or position of the movable pressure plate 120 can be set instead of the speed or position of the cross head 151. Furthermore, the clamping force can be set instead of the position of the cross head (e.g., the clamping position) or the position of the movable pressure plate.

[0054] The toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 and transmits it to the movable pressure plate 120. This amplification factor is also called the toggle ratio. The toggle ratio varies according to the angle θ (hereinafter also called "link angle θ") formed by the first link 152 and the second link 153. The link angle θ is determined based on the position of the crosshead 151. The toggle ratio is at its maximum when the link angle θ is 180°.

[0055] When the thickness of the mold assembly 10 changes due to changes in the mold assembly 10's thickness or temperature, the mold thickness is adjusted to obtain a specified closing force during mold closing. When adjusting the mold thickness, for example, the distance L between the fixed pressure plate 110 and the toggle seat 130 is adjusted such that the linkage angle θ of the toggle mechanism 150 becomes a specified angle at the moment of contact between the movable mold 12 and the fixed mold 11.

[0056] The mold clamping device 100 has a mold thickness adjustment mechanism 180 for adjusting the mold thickness by adjusting the gap L between the fixed pressure plate 110 and the shaft joint seat 130. The mold thickness adjustment mechanism 180 has a threaded shaft 181 formed at the rear end of the connecting rod 140, a nut 182 held rotatably by the shaft joint seat 130, and a mold thickness adjustment motor 183 for rotating the nut 182 that is screwed into the threaded shaft 181.

[0057] Each connecting rod 140 is provided with a threaded shaft 181 and a nut 182. The rotation of the die thickness adjustment motor 183 can be transmitted to multiple nuts 182 via the rotation transmission unit 185. Multiple nuts 182 can rotate synchronously. Alternatively, multiple nuts 182 can be rotated independently by changing the transmission path of the rotation transmission unit 185.

[0058] The rotation transmission unit 185 is, for example, composed of gears. In this case, driven gears are formed on the outer periphery of each nut 182, drive gears are mounted on the output shaft of the die thickness adjustment motor 183, and intermediate gears that mesh with multiple driven gears and drive gears are kept rotatably in the center of the toggle seat 130. Alternatively, the rotation transmission unit 185 can be composed of belts or pulleys instead of gears.

[0059] The action of the mold thickness adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the mold thickness adjustment motor 183 to rotate the nut 182, thereby adjusting the position of the toggle seat 130, which holds the nut 182 in a rotatable position, relative to the fixed pressure plate 110, thereby adjusting the gap L between the fixed pressure plate 110 and the toggle seat 130.

[0060] In addition, in this embodiment, the nut 182 is held in a rotatable position by the toggle seat 130, and the connecting rod 140 with the threaded shaft 181 is fixed to the fixed pressure plate 110, but the present invention is not limited to this.

[0061] For example, the nut 182 can be kept rotatable by the fixed pressure plate 110, and the connecting rod 140 can be fixed to the toggle seat 130. In this case, the interval L can be adjusted by rotating the nut 182.

[0062] Furthermore, the nut 182 can be fixed to the toggle seat 130, and the connecting rod 140 can be kept rotatable by the fixed pressure plate 110. At this time, the interval L can be adjusted by rotating the connecting rod 140.

[0063] Furthermore, the nut 182 can be fixed to the fixed pressure plate 110, and the connecting rod 140 can be kept rotatable by the toggle seat 130. At this time, the interval L can be adjusted by rotating the connecting rod 140.

[0064] The interval L is detected using a die thickness adjustment motor encoder 184. The die thickness adjustment motor encoder 184 detects the amount or direction of rotation of the die thickness adjustment motor 183 and sends a signal indicating the detection result to the control device 700. The detection result of the die thickness adjustment motor encoder 184 is used to monitor or control the position of the toggle seat 130 or the interval L. Furthermore, the toggle seat position detector for detecting the position of the toggle seat 130 and the interval detector for detecting the interval L are not limited to the die thickness adjustment motor encoder 184; general detectors can be used.

[0065] The die thickness adjustment mechanism 180 rotates one of the threaded shaft 181 and nut 182 that are screwed together, thereby adjusting the interval L. Multiple die thickness adjustment mechanisms 180 or multiple die thickness adjustment motors 183 can be used.

[0066] In addition, in order to adjust the interval L, the die thickness adjustment mechanism 180 of this embodiment has a threaded shaft 181 formed on the connecting rod 140 and a nut 182 that engages with the threaded shaft 181, but the present invention is not limited to this.

[0067] For example, the mold thickness adjustment mechanism 180 may also have a connecting rod temperature regulator to adjust the temperature of the connecting rods 140. The connecting rod temperature regulator is installed on each connecting rod 140 and cooperates to adjust the temperature of multiple connecting rods 140. The higher the temperature of the connecting rod 140, the longer the connecting rod 140 becomes due to thermal expansion, and the larger the interval L becomes. The temperature of multiple connecting rods 140 can also be adjusted independently.

[0068] The connecting rod temperature regulator may include, for example, a heater such as a heating element, and regulate the temperature of the connecting rod 140 by heating. The connecting rod temperature regulator may also include a cooler such as a water-cooled jacket, and regulate the temperature of the connecting rod 140 by cooling. Alternatively, the connecting rod temperature regulator may include both a heater and a cooler.

[0069] Furthermore, the mold closing device 100 of this embodiment is a horizontal type with the mold opening and closing direction in the horizontal direction, but it can also be a vertical type with the mold opening and closing direction in the vertical direction. The vertical mold closing device includes a lower pressure plate, an upper pressure plate, a toggle seat, a connecting rod, a toggle mechanism, and a mold closing motor. Either the lower pressure plate or the upper pressure plate is used as a fixed pressure plate, and the other is used as a movable pressure plate. A lower mold is mounted on the lower pressure plate, and an upper mold is mounted on the upper pressure plate. The mold device consists of a lower mold and an upper mold. The lower mold can be mounted on the lower pressure plate via a turntable. The toggle seat is disposed below the lower pressure plate and is connected to the upper pressure plate via a connecting rod. The connecting rod connects the upper pressure plate and the toggle seat at intervals in the mold opening and closing direction. The toggle mechanism is disposed between the toggle seat and the lower pressure plate and raises and lowers the movable pressure plate. The mold closing motor operates the toggle mechanism. When the mold closing device is vertical, the number of connecting rods is usually three. In addition, the number of connecting rods is not particularly limited.

[0070] Additionally, as a drive source, the mold clamping device 100 of this embodiment has a mold clamping motor 160, but a hydraulic cylinder may be used instead of the mold clamping motor 160. Furthermore, the mold clamping device 100 may have a linear motor for mold opening and closing, and an electromagnet for mold clamping.

[0071] (Ejection device)

[0072] Similar to the description of the mold clamping device 100, the description of the ejection device 200 will specify the direction of movement of the movable pressure plate 120 during mold closing. Figure 1 and Figure 2 The right side is set as the front, and the moving direction of the movable pressure plate 120 during mold opening is set as follows: Figure 1 and Figure 2 The middle (left side) is used for explanation.

[0073] Ejection device 200 ejects the molded article from mold device 10. Ejection device 200 includes ejection motor 210, motion conversion mechanism 220 and ejection rod 230, etc.

[0074] The ejector motor 210 is mounted on the movable pressure plate 120. The ejector motor 210 is directly connected to the motion conversion mechanism 220, but it can also be connected to the motion conversion mechanism 220 via a belt or pulley.

[0075] The motion conversion mechanism 220 converts the rotary motion of the ejector motor 210 into the linear motion of the ejector rod 230. The motion conversion mechanism 220 includes a threaded shaft and a nut that engages with the threaded shaft. Ball bearings or rollers can be clamped between the threaded shaft and the nut.

[0076] The ejector rod 230 is designed to move freely in and out of the through hole of the movable pressure plate 120. The front end of the ejector rod 230 contacts the movable component 15, which is configured to move freely in and out inside the movable mold 12. The front end of the ejector rod 230 may or may not be connected to the movable component 15.

[0077] The ejection device 200 performs the ejection process under the control of the control device 700.

[0078] In the ejection process, the ejector motor 210 is driven to advance the ejector rod 230 from the standby position to the ejection position at a set speed, thereby advancing the movable part 15 and ejecting the molded part. Afterwards, the ejector motor 210 is driven to retract the ejector rod 230 at a set speed, thereby retracting the movable part 15 back to its original standby position. The position or speed of the ejector rod 230 is detected, for example, using an ejector motor encoder 211. The ejector motor encoder 211 detects the rotation of the ejector motor 210 and sends a signal indicating its detection result to the control device 700. However, the ejector rod position detector for detecting the position of the ejector rod 230 and the ejector rod speed detector for detecting the speed of the ejector rod 230 are not limited to the ejector motor encoder 211; general detectors can be used.

[0079] (Injection device)

[0080] Unlike the descriptions of the mold clamping device 100 and the ejection device 200, the description of the injection device 300 specifies the direction of movement of the screw 330 during filling. Figure 1 and Figure 2 The left side is taken as the front, and the direction of movement of the screw 330 during measurement is ( Figure 1 and Figure 2 The middle section (right side) is used to explain the background.

[0081] The injection unit 300 is mounted on a sliding base 301 that is movable relative to the frame Fr, and is also movable relative to the mold assembly 10. The injection unit 300 contacts the mold assembly 10 and fills the cavity space 14 within the mold assembly 10 with molding material. The injection unit 300 includes, for example, a cylinder 310, a nozzle 320, a screw 330, a metering motor 340, an injection motor 350, a pressure detector 360, etc.

[0082] The cylinder body 310 heats the molding material supplied to it from the supply port 311. The molding material includes, for example, resin. The molding material is formed in granular form and supplied to the supply port 311 in a solid state. The supply port 311 is formed at the rear of the cylinder body 310. A cooler 312, such as a water-cooled cylinder, is provided on the outer periphery of the rear of the cylinder body 310. A heater 313, such as a belt heater, and a temperature detector 314 are provided on the outer periphery of the cylinder body 310 at a position further forward than the cooler 312.

[0083] Cylinder block 310 in the axial direction of cylinder block 310 ( Figure 1 and Figure 2 The area is divided into multiple zones (from left to right). Each zone is equipped with a heater 313 and a temperature detector 314. For each zone, the control device 700 controls the heater 313 so that the temperature detected by the temperature detector 314 becomes the set temperature.

[0084] The nozzle 320 is located at the front end of the cylinder 310 and is pressed against the mold assembly 10. 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 to make the detected temperature of the nozzle 320 a set temperature.

[0085] The screw 330 is configured within the cylinder 310 to rotate freely and move forward and backward freely. When the screw 330 is rotated, the molding material is fed forward along the spiral grooves of the screw 330. As the molding material is fed forward, it is gradually melted by heat from the cylinder 310. As the liquid molding material is fed forward and accumulates at the front of the cylinder 310, the screw 330 retracts. Then, when the screw 330 is moved forward, the liquid molding material accumulated at the front of the screw 330 is injected from the nozzle 320 and fills the mold assembly 10.

[0086] The check ring 331 is installed at the front of the screw 330 in a self-retracting manner as a check valve to prevent the molding material from flowing backward from the front of the screw 330 when the screw 330 is pushed forward.

[0087] As the screw 330 advances, the check ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and retracts relative to the screw 330 to a closed position that blocks the flow path of the molding material (see reference). Figure 2 This prevents the molding material accumulated in front of the screw 330 from flowing backward.

[0088] On the other hand, when the screw 330 is rotated, the check ring 331 is pushed forward by the pressure of the molding material being fed forward along the spiral groove of the screw 330, and advances relative to the screw 330 to the open position of the open flow path of the molding material (see reference). Figure 1 Thus, the molding material is fed to the front of the screw 330.

[0089] The check ring 331 can 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.

[0090] Additionally, the injection device 300 may have a drive source that moves the check ring 331 back and forth relative to the screw 330 between an open position and a closed position.

[0091] The metering motor 340 rotates the screw 330. The drive source for rotating the screw 330 is not limited to the metering motor 340; for example, it could be a hydraulic pump, etc.

[0092] The injection motor 350 moves the screw 330 forward and backward. A motion conversion mechanism is provided between the injection motor 350 and the screw 330 to convert the rotational motion of the injection motor 350 into the linear motion of the screw 330. The motion conversion mechanism may include, for example, a threaded shaft and a nut that engages with the threaded shaft. Ball bearings or rollers may be provided between the threaded shaft and the nut. The drive source for moving the screw 330 forward and backward is not limited to the injection motor 350; for example, it could be a hydraulic cylinder.

[0093] Pressure detector 360 detects the pressure transmitted between injection motor 350 and screw 330. Pressure detector 360 is located in the force transmission path between injection motor 350 and screw 330, and detects the pressure acting on pressure detector 360.

[0094] The pressure detector 360 sends a signal indicating its detection result to the control device 700. The detection result of the pressure detector 360 is used to control or monitor the pressure exerted on the screw 330 from the molding material, the back pressure on the screw 330, the pressure exerted by the screw 330 on the molding material, etc.

[0095] The injection device 300 performs metering, filling, and pressure holding processes under the control of the control device 700.

[0096] In the metering process, the metering motor 340 drives the screw 330 to rotate at a set speed, feeding the molding material forward along the spiral grooves of the screw 330. Simultaneously, the molding material gradually melts. As the molten molding material is fed forward to the screw 330 and accumulates at the front of the cylinder 310, the screw 330 retracts. The rotational speed of the screw 330 is detected, for example, using a metering motor encoder 341. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends a signal indicating its detection result to the control device 700. Alternatively, the screw speed detector for detecting the rotational speed of the screw 330 is not limited to the metering motor encoder 341; a general detector can be used.

[0097] In the metering process, to limit the rapid retraction of the screw 330, the injection motor 350 can be driven to apply a set back pressure to the screw 330. The back pressure on the screw 330 is detected, for example, using a pressure detector 360. The pressure detector 360 sends a signal indicating its detection result to the control device 700. The metering process ends when the screw 330 retracts to the metering end position and a predetermined amount of molding material accumulates in front of the screw 330.

[0098] In the filling process, the injection motor 350 is driven to advance the screw 330 at a set speed, filling the cavity space 14 within the mold assembly 10 with the liquid molding material accumulated in front of the screw 330. The position or speed of the screw 330 is detected, for example, using an injection motor encoder 351. The injection motor encoder 351 detects the rotation of the injection motor 350 and sends a signal indicating its detection result to the control device 700. If the position of the screw 330 reaches the set position, the process switches from the filling process to the holding pressure process (so-called V / P switching). The position where V / P switching occurs is also called the V / P switching position. The set speed of the screw 330 can be changed according to the position or time of the screw 330.

[0099] Alternatively, after the screw 330 reaches the set position during the filling process, it can be temporarily stopped at that position before V / P switching. Instead of stopping the screw 330, it can be moved forward or backward at a slight speed just before V / P switching. Furthermore, the screw position detector for detecting the position of the screw 330 and the screw speed detector for detecting the speed of the screw 330 are not limited to the injection motor encoder 351; general detectors can be used.

[0100] During the holding pressure process, the injection motor 350 pushes the screw 330 forward, maintaining the pressure of the molding material at the front end of the screw 330 (hereinafter also referred to as "holding pressure") at a set pressure, and pushing the molding material remaining in the cylinder 310 towards the mold assembly 10. This compensates for insufficient molding material caused by cooling shrinkage within the mold assembly 10. The holding pressure is detected, for example, using a pressure detector 360. The pressure detector 360 sends a signal indicating its detection result to the control device 700. The set value of the holding pressure can be changed according to factors such as the time elapsed since the start of the holding pressure process.

[0101] During the holding pressure process, the molding material in the cavity space 14 within the mold assembly 10 is gradually cooled, and at the end of the holding pressure process, the inlet of the cavity space 14 is blocked by the solidified molding material. This state is called gate closure and prevents backflow of molding material from the cavity space 14. A cooling process begins after the holding pressure process. During the cooling process, the molding material within the cavity space 14 solidifies. To shorten the molding cycle time, a metering process can also be performed during the cooling process.

[0102] Furthermore, the injection device 300 in this embodiment is a coaxial screw type, but it can also be a screw pre-plasticizing type, etc. In a screw pre-plasticizing injection device, molten molding material in the plasticizing cylinder is supplied to the injection cylinder, and the molding material is injected from the injection cylinder into the mold device. The screw is configured to rotate freely or rotate freely and retract freely within the plasticizing cylinder, and the plunger is configured to retract freely within the injection cylinder.

[0103] Furthermore, the injection device 300 in this embodiment is horizontal with the cylinder 310's axis in the horizontal direction, but it can also be vertical with the cylinder 310's axis in the vertical direction. The mold clamping device combined with the vertical injection device 300 can be either vertical or horizontal. Similarly, the mold clamping device combined with the horizontal injection device 300 can be either horizontal or vertical.

[0104] (Mobile device)

[0105] Similar to the description of the injection device 300, the description of the moving device 400 will specify the direction of movement of the screw 330 during filling. Figure 1 and Figure 2 The left side is taken as the front, and the direction of movement of the screw 330 during measurement is ( Figure 1 and Figure 2 The middle section (right side) is used to explain the background.

[0106] The moving device 400 moves the injection device 300 forward and backward relative to the mold assembly 10. Furthermore, the moving device 400 presses the nozzle 320 against the mold assembly 10 to generate nozzle contact pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a drive source, and a hydraulic cylinder 430 as a hydraulic actuator, etc.

[0107] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectional rotating pump; by switching the rotation direction of the motor 420, it can draw in working fluid (e.g., oil) from either the first port 411 or the second port 412 and discharge it from the other to generate hydraulic pressure. Additionally, the hydraulic pump 410 can also draw in working fluid from the tank 413 and discharge it from either the first port 411 or the second port 412.

[0108] Motor 420 operates hydraulic pump 410. Motor 420 drives hydraulic pump 410 with a rotational direction and torque corresponding to the control signal from control device 700. Motor 420 can be an electric motor or an electric servo motor.

[0109] 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 interior of the cylinder body 431 into a front chamber 435, which is a first chamber, and a rear chamber 436, which is a second chamber. The piston rod 433 is fixed to a fixed pressure plate 110. The piston rod 433 passes through the front chamber 435, therefore the cross-sectional area of ​​the front chamber 435 is smaller than the cross-sectional area of ​​the rear chamber 436.

[0110] The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via a first flow path 401. Working fluid discharged from the first port 411 is supplied to the front chamber 435 via the first flow path 401, thereby propelling the injection device 300 forward. As the injection device 300 advances, the nozzle 320 is pressed against the fixed mold 11. The front chamber 435 functions as a pressure chamber to generate the nozzle contact pressure of the nozzle 320 by the pressure of the working fluid supplied from the hydraulic pump 410.

[0111] 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 working 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, thereby pushing the injection device 300 backward. The injection device 300 retracts, thereby separating the nozzle 320 from the fixed mold 11.

[0112] The first safety valve 441 opens when the pressure in the first flow path 401 exceeds the set value, and returns the excess working fluid in the first flow path 401 to the tank 413, thereby keeping the pressure in the first flow path 401 below the set value.

[0113] The second safety valve 442 opens when the pressure in the second flow path 402 exceeds the set value, and returns the excess working fluid in the second flow path 402 to the tank 413, thereby keeping the pressure in the second flow path 402 below the set value.

[0114] The flushing valve 443 is a valve used to adjust the excess or deficiency of the working fluid circulation caused by the difference in cross-sectional area between the front chamber 435 and the rear chamber 436. Figure 1 and Figure 2 As shown, for example, it consists of a three-position four-way slide valve.

[0115] The first check valve 451 opens when the pressure in the first flow path 401 is lower than the pressure in the tank 413, and supplies working fluid from the tank 413 to the first flow path 401.

[0116] The second check valve 452 opens when the pressure in the second flow path 402 is lower than the pressure in the tank 413, and supplies working fluid from the tank 413 to the second flow path 402.

[0117] The solenoid switching valve 453 is a control valve that controls the flow of working fluid between the front chamber 435 of the hydraulic cylinder 430 and the first port 411 of the hydraulic pump 410. The solenoid switching valve 453 is, for example, located in the middle of the first flow path 401 and controls the flow of working fluid in the first flow path 401.

[0118] like Figure 1 and Figure 2 As shown, the electromagnetic switching valve 453 is, for example, a two-position two-way spool valve. When the spool valve is in the first position ( Figure 1 and Figure 2 In the left-hand position, bidirectional flow is allowed between the anterior chamber 435 and the first port 411. On the other hand, when the slide valve is in the second position (…),… Figure 1 and Figure 2 In the case of the position on the right side of the middle, the flow from the anterior chamber 435 to the first port 411 is restricted. At this time, the flow from the first port 411 to the anterior chamber 435 is not restricted, but it can still be restricted.

[0119] The first pressure detector 455 detects the hydraulic pressure in the front chamber 435. The nozzle contact pressure is generated by the hydraulic pressure in the front chamber 435, and therefore can be detected using the first pressure detector 455. The first pressure detector 455 is, for example, located midway through the first flow path 401, and positioned on the front chamber 435 side with reference to the solenoid switching valve 453. The nozzle contact pressure can be detected regardless of the state of the solenoid switching valve 453.

[0120] The second pressure detector 456 is located midway through the first flow path 401, positioned relative to the solenoid valve 453 on the side of the first port 411. The second pressure detector 456 detects the hydraulic pressure between the solenoid valve 453 and the first port 411. When the solenoid valve 453 is in a state allowing bidirectional flow between the first port 411 and the front chamber 435, the hydraulic pressure between the first port 411 and the solenoid valve 453 is equal to the hydraulic pressure between the solenoid valve 453 and the front chamber 435. Therefore, in this state, the nozzle contact pressure can be detected using the second pressure detector 456.

[0121] In this embodiment, a pressure detector located midway through the first flow path 401 is used to detect the nozzle contact pressure. However, for example, a force sensor located at the nozzle 320 may also be used to detect the nozzle contact pressure. That is, the pressure detector for detecting the nozzle contact pressure may be located in either the moving device 400 or the injection device 300.

[0122] In addition, in this embodiment, the moving device 400 includes a hydraulic cylinder 430, but the present invention is not limited thereto. For example, an electric motor and a motion conversion mechanism that converts the rotational motion of the electric motor into the linear motion of the injection device 300 can be used instead of the hydraulic cylinder 430.

[0123] (Control device)

[0124] like Figures 1-2 As shown, the control device 700 is, for example, a computer, and includes a CPU (Central Processing Unit) 701, a storage medium 702 such as a memory, an input interface 703, and an output interface 704. The control device 700 performs various controls by having the CPU 701 execute programs stored in the storage medium 702. Furthermore, the control device 700 receives signals from external sources through the input interface 703 and sends signals to external sources through the output interface 704.

[0125] The control device 700 repeatedly manufactures molded articles by repeatedly performing mold closing, mold fitting, and mold opening processes. Furthermore, the control device 700 performs metering, filling, and holding pressure processes during the mold fitting process. The series of actions used to obtain the molded article, such as the actions from the start of the metering process to the start of the next metering process, is also referred to as "injection" or "molding cycle." The time required for one injection is also referred to as "molding cycle time."

[0126] A single molding cycle may include, for example, a metering process, a mold closing process, a mold closing process, a filling process, a pressure holding process, a cooling process, a mold opening process, and an ejection process in sequence. This sequence refers to the order in which each process begins. The filling, pressure holding, and cooling processes are performed from the start of the mold closing process to the end of the mold closing process. The end of the mold closing process coincides with the start of the mold opening process. Alternatively, to shorten the molding cycle time, multiple processes can be performed simultaneously. For example, the metering process can be performed during the cooling process of the previous molding cycle; in this case, the mold closing process can be set to be performed first in the molding cycle. Furthermore, the filling process can begin during the mold closing process. And the ejection process can begin during the mold opening process. When an on / off valve is provided to control the flow path of the nozzle 320, the mold opening process can begin during the metering process. This is because even if the mold opening process begins during the metering process, as long as the on / off valve closes the flow path of the nozzle 320, the molding material will not leak from the nozzle 320.

[0127] The control device 700 is connected to the operating device 750 or the display device 760. The operating device 750 receives user input operations and outputs a signal corresponding to the input operation to the control device 700. Under the control of the control device 700, the display device 760 displays an operation screen corresponding to the input operation in the operating device 750. The operation screen is used for setting the injection molding machine, etc. Multiple operation screens are prepared and can be switched or overlaid. The user observes the operation screen displayed on the display device 760 while operating the operating device 750, thereby setting the injection molding machine (including inputting setting values), etc. The operating device 750 and the display device 760 can be, for example, a touch panel and formed as a single unit. In this embodiment, the operating device 750 and the display device 760 are formed as a single unit, but they can also be set independently. Furthermore, multiple operating devices 750 can be provided.

[0128] (Opening and closing of the nozzle of the injection device)

[0129] Figure 3 It means by making Figure 5 The swing lever shown swings in the first direction (e.g., clockwise) to cause the valve core to... Figure 5 The diagram shows the state of the open position moving to the closed position. Figure 4 It means to make Figure 3 The diagram shows the state of the swing arm swinging in the second direction (e.g., counterclockwise). Figure 5 This indicates that the pressure generated in the metering process of the molding material causes... Figure 4 The diagram shows the state of the valve core moving from the closed position to the closed position.

[0130] The injection apparatus 300 includes a flow path opening and closing mechanism 329 for opening and closing the flow path 321 of the molding material in the nozzle 320. The flow path opening and closing mechanism 329 has an open position for opening the flow path 321 (see reference). Figure 5 ) and the closed position of open flow path 321 (reference) Figure 3 The valve core 322 moves between the closed and open positions. When the valve core 322 is in the closed position, a wedge-shaped gap 323 with a narrowing opening facing forward can be formed between the valve core 322 and the wall of the flow path 321. If the pressure of the molding material at the wedge-shaped gap 323 becomes sufficiently large, the valve core 322 overcomes the adhesive force of the molding material and moves from the closed position to the open position.

[0131] The movement direction of the valve core 322 can be orthogonal to the axial direction of the nozzle 320, or radial to the flow path 321 of the nozzle 320. In this embodiment, the movement direction of the valve core 322 is orthogonal to the axial direction of the nozzle 320, but it can also be the axial direction of the nozzle 320, as is the case previously. However, when the movement direction of the valve core 322 is the axial direction of the nozzle 320, the valve core 322 is located inside the flow path 321 not only in the closed position but also in the open position, thus narrowing the diameter of the flow path 321 by the amount of the valve core. On the other hand, according to this embodiment, when the valve core 322 moves from the closed position to the open position, the valve core 322 exits from the flow path 321, thus allowing the molding material to easily pass through the nozzle during the filling process. This reduces the flow resistance of the molding material in the nozzle 320 during the filling process and suppresses the heating of the molding material. Therefore, the cooling process time can be shortened, thereby shortening the molding cycle.

[0132] In addition, the moving direction of the valve core 322 in this embodiment is orthogonal to the axial direction of the nozzle 320, but it can also be the axial direction of the nozzle 320 as in the past.

[0133] The flow path opening and closing mechanism 329 includes a valve core moving mechanism 324 that moves the valve core 322 between an open position and a closed position. The valve core moving mechanism 324 performs actions to move the valve core 322 from the open position to the closed position and fix the valve core 322 in the closed position, and to release the valve core 322 from the closed position, thereby moving the valve core 322 to the open position under the pressure of the molding material stored inside the nozzle 320. The valve core moving mechanism 324, for example, includes a swing rod 325 mounted relative to the nozzle 320 and pivotally abutting against the valve core 322, and a first direction (in which the swing rod 325 moves the valve core 322 from the open position to the closed position) for moving the swing rod 325. Figures 3-5 The first direction is clockwise, and the second direction is opposite to the first direction and releases the valve core 322 from the closed position. Figures 3-5 The fluid pressure cylinder 326 swings counterclockwise.

[0134] The swing rod 325 is designed to swing freely around the swing shaft 371 fixed to the nozzle 320, and swings by the extension and retraction of the fluid pressure cylinder 326. The swing rod 325 is in contact with the valve core 322, but is not connected to the valve core 322.

[0135] The fluid pressure cylinder 326 has a cylinder body 327 and a piston rod 328 that moves under pressure from fluid supplied to the interior of the cylinder body 327. The base of the piston rod 328 is connected to a piston that slides inside the cylinder body 327. The piston divides the interior of the cylinder body 327 into two chambers. By supplying pressure to either chamber, the piston moves, thereby moving the piston rod 328.

[0136] The cylinder body 327 is configured to swing freely around a pivot shaft 372 fixed to the nozzle 320. On the other hand, the piston rod 328 is connected to the pivot rod 325 via a pin 373, allowing it to swing freely. Alternatively, the cylinder body 327 and piston rod 328 can be configured in reverse order. That is, the cylinder body 327 can be connected to the pivot rod 325 via a pin 373, and the piston rod 328 can swing freely around the pivot shaft 372.

[0137] like Figure 5 As shown, if the fluid pressure cylinder 326 is extended with the valve core 322 in the open position, the swing rod 325 swings in the first direction (e.g., clockwise). Thus, as... Figure 3 As shown, the valve core 322 is pressed by the swing rod 325 and moved to the closed position, and is fixed in the closed position by the pressure of the fluid pressure cylinder 326.

[0138] On the other hand, such as Figure 3As shown, if the fluid pressure cylinder 326 is shortened while the valve core 322 is in the closed position, the swing rod 325 swings in a second direction (e.g., counterclockwise) opposite to the first direction. Thus, as... Figure 4 As shown, the swing arm 325 returns to its original position, thus not hindering the movement of the valve core 322 from the closed position to the open position. Therefore, the valve core 322 in the closed position is released, thereby allowing the valve core 322 to move to the open position by the pressure of the molding material stored inside the nozzle 320.

[0139] As a result, the valve core 322 is forced to move by the pressure of the molding material at the wedge-shaped gap 323. Figure 4 The closed position shown is moved to Figure 5 The valve core 322 moves from the closed position to the open position. This movement can occur simultaneously with or after the second-direction swing of the swing rod 325.

[0140] In this embodiment, the driving force of the fluid pressure cylinder 326 is used to return the swing rod 325 to its original position in the second direction, but the pressure of the molding material generated during the metering process can also be used. At this time, the control device 700 releases pressure from the fluid pressure cylinder 326 instead of supplying pressure, thereby allowing free flow of fluid between the two chambers divided by the piston and the outside. For example, if the fluid pressure cylinder 326 is a pneumatic cylinder, the two chambers divided by the piston are opened to the atmosphere. Thus, the piston can move freely in both directions. Therefore, the pressure of the molding material generated during the metering process can be used to move the valve core 322 from the closed position to the open position, and the swing rod 325 can be swung in the second direction by pressing the swing rod 325 with the valve core 322. When the pressure of the molding material generated during the metering process is used to return the swing rod 325 to its original position, the swing rod 325 and the valve core 322 can also be connected by a pin or the like.

[0141] During a single injection (e.g., from the start of the metering process to the start of the next metering process), the control device 700 reciprocates the valve core 322 between an open position and a closed position. The valve core 322 is positioned, for example, in the open position during the filling and holding pressure processes, and in the closed position at the start of the metering process. The valve core 322 moves from the open position to the closed position after the holding pressure process ends and before the metering process begins. Furthermore, the valve core 322 moves from the closed position to the open position due to the pressure of the molding material stored inside the nozzle 320 after the metering process begins and before the filling process begins.

[0142] The metering process is the process of storing molding material in the front part of the cylinder 310. The start of the metering process refers to starting the operation of the screw 330 used to store molding material in the front part of the cylinder 310. For example, the start of the metering process is the start of rotation of the screw 330. By rotating the screw 330, the molding material is fed forward along the spiral groove of the screw 330, and as it accumulates in the front part of the cylinder 310, the screw 330 retracts. Alternatively, in this embodiment, the start of the metering process is the start of rotation of the screw 330, but it could also be the start of retraction of the screw 330. That is, in the metering process, the screw 330 can be rotated after retracting a predetermined amount. If the screw 330 reaches the metering end position, the metering process ends, and the rotation and retraction of the screw 330 are stopped.

[0143] The filling process is the process of filling the mold assembly 10 with molding material stored in the front of the cylinder 310. The start filling process indicates the initiation of the operation of the screw 330, which is used to fill the mold assembly 10 with the molding material stored in the front of the cylinder 310. For example, the start filling process is the initiation of the forward movement of the screw 330. During the filling process, the screw 330 may not rotate. If the screw 330 reaches the V / P switching position, the filling process ends, and a holding pressure process is performed.

[0144] Furthermore, the valve core 322 can be in a closed position from the start of the metering process to the end of the metering process, and can be moved from the closed position to the open position after the end of the metering process and before the start of the filling process. In this case, if the mold opening process is started after the start of the metering process and before the end of the metering process, leakage of molding material from the nozzle 320 can be prevented.

[0145] Figure 6 This is a diagram illustrating the timing of the processes performed by the injection device according to one embodiment, the movement of the oscillating rod, and the movement of the valve core. (See diagram for example.) Figure 6 As shown, the injection unit 300 repeatedly performs metering, back-pulling, filling, and holding pressure processes. The back-pulling process refers to the process of stopping the rotation of the screw 330 and retracting the screw 330 after the metering process ends and before the filling process begins, in order to reduce the pressure of the molding material accumulated in front of the screw 330.

[0146] The control device 700 supplies pressure to the fluid pressure cylinder 326 at a preset time to cause the swing rod 325 to swing in the first direction, and presses the valve core 322 through the swing rod 325 to move the valve core 322 from the open position to the closed position.

[0147] like Figure 6 As shown, the swing of the swing lever 325 in the first direction is performed, for example, at a predetermined time from the end of the pressure holding process to the start of the metering process (e.g., when the pressure holding process ends).

[0148] The movement of valve core 322 from the open position to the closed position is achieved by the swinging of swing rod 325 in the first direction. Therefore, the movement of valve core 322 from the open position to the closed position can occur simultaneously with the swinging of swing rod 325 in the first direction. Valve core 322 is fixed in the closed position by the pressure of fluid pressure cylinder 326.

[0149] Furthermore, the swinging of the swing rod 325 in the first direction and the movement of the valve core 322 from the open position to the closed position can be performed midway through the metering process, as long as the pressure holding process ends and the mold opening process begins. During the period after the pressure holding process ends and before the mold opening process begins, the mold assembly 10 is filled with molding material, so even if the metering process is performed with the flow path 321 open, the molding material will not leak from the nozzle 320 that is in contact with the mold assembly 10.

[0150] Furthermore, the control device 700 supplies pressure to the fluid pressure cylinder 326 at a preset time, causing the swing rod 325 to swing in the second direction, thereby returning the swing rod 325 to its original position. Thus, the swing rod 325 does not obstruct the movement of the valve core 322 from the closed position to the open position. Therefore, the valve core 322 in the closed position is released, allowing the valve core 322 to move to the open position under the pressure of the molding material stored inside the nozzle 320.

[0151] like Figure 6 As shown, the swing of the swing arm 325 in the second direction occurs, for example, at a predetermined time from the middle of the metering process to the start of the back-draining process (e.g., just before or when the metering process is about to end). Furthermore, when the back-draining process is not performed, the swing of the swing arm 325 in the second direction occurs at a predetermined time from the middle of the metering process to the start of the filling process.

[0152] The movement of valve core 322 from the closed position to the open position is achieved by the pressure of the molding material stored inside nozzle 320 during the period from the start of the metering process to the start of the filling process. Valve core 322 is moved to the open position by the back pressure or residual back pressure of screw 330 during the metering process. Therefore, the movement of valve core 322 from the closed position to the open position can occur simultaneously with or after the swing arm 325 swings in the second direction.

[0153] like Figure 6As shown, the movement of valve core 322 from the closed position to the open position is performed, for example, at a predetermined time from the middle of the metering process to before the start of the back-pull process. Furthermore, if the back-pull process is not performed, the movement of valve core 322 from the closed position to the open position is performed at a predetermined time from the middle of the metering process to before the start of the filling process.

[0154] The control device 700 can also be set with a predetermined delay time from the end of the metering process to the start of the back-drawing process. For example... Figure 7 As shown, during this delay time, in order to move the valve core 322 from the closed position to the open position, a pressure-increasing process can be performed to increase the pressure of the molding material inside the nozzle 320. Compared to the metering process, the pressure of the molding material inside the nozzle 320 is higher in the pressure-increasing process. If the time elapsed since the end of the metering process reaches the delay time, a back-pulling process begins. As described above, if the back-pulling process begins, the pressure of the molding material inside the nozzle 320 decreases (see reference). Figure 7 Therefore, in this embodiment, the pressure increase process is performed after the metering process ends and before the back-draining process begins. Alternatively, the back-draining process may be omitted, and the pressure increase process may be performed after the metering process ends and before the filling process begins.

[0155] like Figure 7 As shown, if a delay time is set from the end of the metering process to the start of the reverse drawing process, the pressure of the molding material will increase due to the inertial flow of the molding material even if the screw 330 stops at the metering end position. Furthermore, if the screw 330 is detected to have reached the metering end position, its rotation and movement will stop. Even if the movement of the screw 330 stops but its rotation has not, the molding material will be fed forward from the screw 330, thus becoming the main reason for the increased pressure of the molding material.

[0156] The retraction speed of the screw 330 in the metering process is lower than the forward speed of the screw 330 in the filling process. Therefore, the pressure of the molding material generated when the retraction stops is lower than the pressure of the molding material generated in the filling process.

[0157] Therefore, by utilizing the pressure of the molding material when the screw 330 stops at the metering end position to move the valve core 322 to the open position, it is possible to reliably move the valve core 322 to the open position while suppressing damage to the valve core 322 and the valve core moving mechanism 324.

[0158] If the screw 330 is detected to have reached the metering end position while the valve core 322 is in the closed position, the swing rod 325 is swung in the second direction. Thus, the pressure of the molding material at which the screw 330 stops at the metering end position can move the valve core 322 from the closed position to the open position.

[0159] Alternatively, the back-pull process can be omitted, allowing the filling process to begin after a predetermined time has elapsed after the screw 330 has stopped at the metering end position. Without the back-pull process, a delay time can be set from the end of the metering process to the start of the filling process. If the elapsed time from the end of the metering process reaches the delay time, the filling process begins.

[0160] The delay time from the end of the metering process to the start of the reverse extraction process can be used as the waiting time for the valve core 322 to move from the closed position to the open position, or it can be used as the processing time for further increasing the pressure of the molding material in front of the screw 330, the details of which will be described later.

[0161] As described above, in this embodiment, the control device 700 releases the valve core 322, which is in the closed position, after the metering process begins and before the filling process begins, thereby performing control to move the valve core 322 to the open position by the pressure of the molding material stored inside the nozzle 320. Thus, after the metering process begins and before the filling process begins, the valve core 322 moves from the closed position to the open position by the pressure of the molding material stored inside the nozzle 320. The pressure of the molding material generated from the start of the metering process to the start of the filling process is less than the pressure of the molding material generated in the filling process. This is because, unlike the filling process, no molding material is injected from the nozzle 320 in the metering process. Furthermore, according to this embodiment, the movement of the valve core 322 from the closed position to the open position utilizes the pressure of the molding material generated from the start of the metering process to the start of the filling process. Therefore, compared to the conventional case where the pressure of the molding material generated in the filling process is utilized, the momentum of the valve core 322 moving from the closed position to the open position can be suppressed, thereby suppressing damage to the valve core 322 or the valve core moving mechanism 324 caused by impact.

[0162] The pressure of the molding material generated in the metering process can be utilized from the end of the metering process until the start of the reverse extraction process. In this specification, the end of the metering process means that the screw 330 is retracted to a set position by the rotation of the screw 330, and a predetermined amount of molding material is accumulated in front of the screw 330.

[0163] Therefore, the control device 700 can also increase the pressure of the molding material in front of the screw 330 by stopping the forward and backward movement of the screw 330 and rotating the screw 330 to feed the molding material in front of the screw 330 after the metering process ends and before the valve core 322 moves from the closed position to the open position. The valve core 322 can be moved from the closed position to the open position using both the pressure of the molding material generated during the metering process and the pressure of the molding material generated by the rotation of the screw 330 after the metering process ends. This is particularly effective when the back pressure of the screw 330 is low during the metering process. The amount of rotation of the screw 330 after the metering process ends is adjusted so that the pressure of the molding material during the movement of the valve core 322 from the closed position to the open position is below a set value. This is to prevent damage to the valve core 322 or the valve core moving mechanism 324.

[0164] Furthermore, the control device 700 can also increase the pressure of the molding material in front of the screw 330 by stopping the rotation of the screw 330 and advancing the screw 330 after the metering process ends and before the valve core 322 moves from the closed position to the open position. The valve core 322 can be moved from the closed position to the open position using both the pressure of the molding material generated during the metering process and the pressure of the molding material generated by the advance of the screw 330 after the metering process ends. This is particularly effective when the back pressure of the screw 330 is low during the metering process. The advance amount of the screw 330 after the metering process ends is adjusted so that the pressure of the molding material during the movement of the valve core 322 from the closed position to the open position is below a set value. This is to prevent damage to the valve core 322 or the valve core movement mechanism 324.

[0165] Furthermore, the control device 700 can also increase the pressure of the molding material in front of the screw 330 by advancing and rotating the screw 330 after the metering process ends and before the valve core 322 moves from the closed position to the open position. The valve core 322 can be moved from the closed position to the open position using both the pressure of the molding material generated during the metering process and the pressure of the molding material generated by the advance and rotation of the screw 330 after the metering process ends. This is particularly effective when the back pressure of the screw 330 is low during the metering process. The advance amount of the screw 330 after the metering process ends and the rotation amount of the screw after the metering process ends are adjusted so that the pressure of the molding material during the movement of the valve core 322 from the closed position to the open position is below a set value. This is to prevent damage to the valve core 322 or the valve core movement mechanism 324.

[0166] (Modifications and Improvements)

[0167] The above describes the implementation methods of the injection molding machine, but the present invention is not limited to the above-described implementation methods, and various modifications and improvements can be made within the scope of the spirit of the present invention described in the technical solution.

[0168] This application claims priority based on Japanese Patent Application No. 2017-016341, filed with the Japan Patent Office on January 31, 2017, and the entire contents of Japanese Patent Application No. 2017-016341 are incorporated herein by reference.

[0169] Symbol Explanation

[0170] 10-Mold assembly, 11-Fixed mold, 12-Modible mold, 300-Injection device, 310-Cylinder, 320-Nozzle, 321-Flow path, 322-Valve core, 324-Valve core moving mechanism, 325-Swing rod, 326-Fluid pressure cylinder, 329-Flow path opening and closing mechanism, 330-Screw, 340-Metering motor, 350-Injection motor, 700-Control device.

Claims

1. An injection molding machine, comprising: The nozzle injects molding material into the mold assembly; The cylinder body has the nozzle provided at its front end; and A flow path opening and closing mechanism includes: a valve core that moves between an open position (opening the flow path of the molding material) and a closed position (closing the flow path) in a direction orthogonal to the axial direction of the nozzle; and a valve core moving mechanism that contacts but is not connected to the valve core, moving the valve core from the open position to the closed position. After the metering process of storing the molding material in the front of the cylinder begins and before the filling process of filling the mold device with the molding material stored in the front of the cylinder begins, the valve core moving mechanism releases contact with the valve core located in the closed position. After the release, the valve core moves to the open position by the pressure of the molding material. It also includes a swing arm, which contacts the valve core. The movement of the valve core from the closed position to the open position occurs later than the swing of the swing rod. When the valve core is in the closed position, a wedge-shaped gap with a narrowing opening is formed between the valve core and the wall of the flow path, facing forward.

Images