Injection molding machine, heat limiting member, and heat input suppression method

Abstract

To provide a technique capable of reducing heat input to tie bars.SOLUTION: An injection molding machine moves a movable platen, on which a movable mold is mounted, with respect to a stationary platen, on which a stationary mold is mounted, along tie bars to open / close the stationary mold and the movable mold. The injection molding machine has thermal restriction members that restrict moving of air heated to a room temperature around the tie bars or more to the tie bars.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to an injection molding machine, a heat limiting member, and a heat input suppression method. [Background technology]

[0002] The mold unit installed in the injection molding machine is adjusted to the temperature required for the molded product by supplying and discharging a temperature control medium through piping. The heat from the mold unit is transferred to the tie bars, for example, via the platens (fixed platen, movable platen), and affects the amount of elongation of the tie bars when clamping force is generated.

[0003] For this reason, Patent Document 1 proposes a structure in which a heat insulating material is sandwiched between the platen and the tie bars within the platen to suppress direct heat transfer from the platen to the tie bars. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2008-296384 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is difficult to select a heat insulating material that can withstand the load applied when the mold assembly is clamped and has a high heat insulating effect. Furthermore, during injection molding by an injection molding machine, the mold assembly and piping heat the surrounding air. The injection molding machine disclosed in Patent Document 1 has tie bars that extend from the platen in an exposed state. Therefore, the air heated by the mold assembly and piping directly enters the tie bars.

[0006] In particular, the amount of heat input to the four tie bars varies depending on the shape of the mold, the position of the piping, etc. This can cause the four tie bars to stretch unevenly, resulting in an unstable clamping force and potentially having a major impact on the molding of the molded product.

[0007] The present invention provides a technology that can stabilize molding accuracy by suppressing the tie bars from being heated and stretched through air. [Means for solving the problem]

[0008] One aspect of the present invention is an injection molding machine that opens and closes the fixed mold and the movable mold by moving a movable platen on which a movable mold is installed along tie bars relative to a fixed platen on which a fixed mold is installed, and has a thermal restriction section that restricts air heated above room temperature around the tie bar from moving over the tie bar.

[0009] Another aspect of the present invention is a thermal limiting member that is attached to an injection molding machine that opens and closes the fixed mold and the movable mold by moving a movable platen, on which a movable mold is installed, along tie bars relative to a fixed platen on which a fixed mold is installed, and when attached to the tie bar, the thermal limiting member restricts air heated to a temperature above room temperature around the tie bar from moving toward the tie bar.

[0010] Another aspect of the present invention is a heat input suppression method for limiting heat input to tie bars in an injection molding machine in which a movable platen on which a movable mold is installed is moved along tie bars relative to a fixed platen on which a fixed mold is installed to open and close the fixed mold and the movable mold, thereby restricting air heated to above room temperature around the tie bars from moving toward the tie bars. [Effects of the Invention]

[0011] The injection molding machine, heat limiting member, and heat input suppression method according to the present invention can stabilize molding accuracy by suppressing the tie bars from being heated through the air and stretching. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 2 is a diagram illustrating a state when mold opening of the injection molding machine according to the embodiment is completed. [Figure 2] FIG. 2 is a diagram illustrating a state during mold clamping of the injection molding machine according to the embodiment. [Figure 3] FIG. 2 is a diagram schematically illustrating the support side of a fixed mold in a mold clamping device. [Figure 4] FIG. 10 illustrates the attachment of the thermal limiting portion to the tie bar. [Figure 5] FIG. 10 is a diagram schematically illustrating a thermal limiting portion according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and redundant explanations may be omitted.

[0014] (injection molding machine) FIG. 1 is a diagram showing a state of an injection molding machine according to an embodiment when mold opening is completed. FIG. 2 is a diagram showing a state of an injection molding machine according to an embodiment when mold clamping is performed. In this specification, the X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other. The X-axis direction and Y-axis direction represent horizontal directions, and the Z-axis direction represents vertical directions. When the mold clamping device 100 is of 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 of the Y-axis direction is called the operating side, and the positive side of the Y-axis direction is called the counter-operating side.

[0015] As shown in FIGS. 1 and 2 , injection molding machine 10 includes a mold clamping unit 100 that opens and closes mold apparatus 800, an ejector unit 200 that ejects a molded product molded by mold apparatus 800, an injection unit 300 that injects molding material into mold apparatus 800, a moving unit 400 that moves injection unit 300 forward and backward relative to mold apparatus 800, a control unit 700 that controls each component of injection molding machine 10, and a frame 900 that supports each component of injection molding machine 10. Frame 900 includes a mold clamping unit frame 910 that supports mold clamping unit 10 and an injection unit frame 920 that supports injection unit 300. Clamping unit frame 910 and injection unit frame 920 are each installed on floor 2 via leveling adjusters 930. Control unit 700 is disposed in the interior space of injection unit frame 920. Each component of injection molding machine 10 will be described below.

[0016] (mold clamping device) In the description of the mold clamping unit 100, the moving direction of the movable platen 120 during mold closing (for example, the positive X-axis direction) is defined as the front, and the moving direction of the movable platen 120 during mold opening (for example, the negative X-axis direction) is defined as the rear.

[0017] The mold clamping device 100 performs mold closing, pressure increase, mold clamping, depressurization, and mold opening of the mold device 800. The mold device 800 includes a fixed mold 810 and a movable mold 820.

[0018] The mold clamping unit 100 is, for example, a horizontal type, and the mold opening and closing direction is horizontal. The mold clamping unit 100 has a fixed platen 110 to which a fixed mold 810 is attached, a movable platen 120 to which a movable mold 820 is attached, and a movement mechanism 102 that moves the movable platen 120 relative to the fixed platen 110 in the mold opening and closing direction.

[0019] The stationary platen 110 is fixed to the mold clamping unit frame 910. A stationary mold 810 is attached to the surface of the stationary platen 110 that faces the movable platen 120.

[0020] The movable platen 120 is disposed so as to be movable in the mold opening / closing direction relative to the mold clamping unit frame 910. A guide 101 for guiding the movable platen 120 is installed on the mold clamping unit frame 910. A movable mold 820 is attached to the surface of the movable platen 120 facing the fixed platen 110.

[0021] The moving mechanism 102 moves the movable platen 120 forward and backward relative to the fixed platen 110, thereby performing mold closing, pressurization, mold clamping, depressurization, and mold opening of the mold apparatus 800. The moving mechanism 102 has a toggle support 130 arranged at a distance from the fixed platen 110, tie bars 140 connecting the fixed platen 110 and the toggle support 130, a toggle mechanism 150 that moves the movable platen 120 in the mold opening / closing direction relative to the toggle support 130, a mold clamping motor 160 that operates the toggle mechanism 150, a motion conversion mechanism 170 that converts the rotational motion of the mold clamping motor 160 into linear motion, and a mold thickness adjustment mechanism 180 that adjusts the distance between the fixed platen 110 and the toggle support 130.

[0022] The toggle support 130 is disposed at a distance from the fixed platen 110 and is placed on the mold clamping unit frame 910 so as to be freely movable in the mold opening and closing direction. The toggle support 130 may be disposed so as to be freely movable along a guide laid on the mold clamping unit frame 910. The guide of the toggle support 130 may be the same as the guide 101 of the movable platen 120.

[0023] In this embodiment, the fixed platen 110 is fixed to the mold clamping unit frame 910, and the toggle support 130 is arranged so as to be freely movable in the mold opening and closing direction relative to the mold clamping unit frame 910, but the toggle support 130 may also be fixed to the mold clamping unit frame 910, and the fixed platen 110 may be arranged so as to be freely movable in the mold opening and closing direction relative to the mold clamping unit frame 910.

[0024] The tie bars 140 connect the fixed platen 110 and the toggle support 130 at an interval L in the mold opening / closing direction. A total of four tie bars 140 are provided at each of the four corners of the fixed platen 110. The number of tie bars 140 to be provided is not particularly limited, and it is sufficient that one or more tie bars are provided.

[0025] The four tie bars 140 are arranged parallel to the mold opening / closing direction and extend in response to the mold clamping force. At least one tie bar 140 may be provided with a tie bar strain detector 141 that detects strain in the tie bar 140. The tie bar strain detector 141 sends a signal indicating the detection result to the control device 700. The detection result of the tie bar strain detector 141 is used to detect the mold clamping force, etc.

[0026] In this embodiment, the tie bar strain detector 141 is used as the mold clamping force detector that detects the mold clamping force, but the present invention is not limited to this. The mold clamping force detector is not limited to the strain gauge type, and may be a piezoelectric type, a capacitance type, a hydraulic type, an electromagnetic type, or the like, and the attachment position thereof is also not limited to the tie bar 140.

[0027] The toggle mechanism 150 is disposed between the movable platen 120 and the toggle support 130 and moves the movable platen 120 relative to the toggle support 130 in the mold opening / closing direction. The toggle mechanism 150 has a crosshead 151 that moves in the mold opening / closing direction and a pair of link groups that bend and extend with the movement of the crosshead 151. Each of the pair of link groups has a first link 152 and a second link 153 that are connected to bendable and extendable by a pin or the like. The first link 152 is attached to the movable platen 120 by a pin or the like so that it can swing freely. The second link 153 is attached to the toggle support 130 by a pin or the like so that it can swing freely. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 advances or retreats relative to the toggle support 130, the first link 152 and the second link 153 bend and extend, and the movable platen 120 advances or retreats relative to the toggle support 130.

[0028] The configuration of toggle mechanism 150 is not limited to the configuration shown in Figures 1 and 2. For example, although each link group has five nodes in Figures 1 and 2, it may have four nodes, and one end of third link 154 may be connected to a node between first link 152 and second link 153.

[0029] The mold clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The mold clamping motor 160 moves the crosshead 151 forward and backward relative to the toggle support 130, thereby bending and extending the first link 152 and the second link 153 and moving the movable platen 120 forward and backward relative to the toggle support 130. The mold clamping motor 160 is directly connected to the motion conversion mechanism 170, but may also be connected to the motion conversion mechanism 170 via a belt, a pulley, or the like.

[0030] The motion conversion mechanism 170 converts the rotational motion of the mold clamping motor 160 into the linear motion of the crosshead 151. The motion conversion mechanism 170 includes a screw shaft and a screw nut that screws onto the screw shaft. A ball or roller may be interposed between the screw shaft and the screw nut.

[0031] The mold clamping unit 100 performs a mold closing process, a pressure increasing process, a mold clamping process, a pressure reducing process, a mold opening process, and the like under the control of the control device 700.

[0032] In the mold closing process, the mold clamping motor 160 is driven to move the crosshead 151 forward at a set movement speed to a mold closing completion position, thereby moving the movable platen 120 forward and bringing the movable mold 820 into contact with the fixed mold 810. The position and movement speed of the crosshead 151 are detected using, for example, a mold clamping motor encoder 161. The mold clamping motor encoder 161 detects the rotation of the mold clamping motor 160 and sends a signal indicating the detection result to the control device 700.

[0033] The crosshead position detector that detects the position of the crosshead 151 and the crosshead movement speed detector that detects the movement speed of the crosshead 151 are not limited to the mold clamping motor encoder 161, and general types can be used. Furthermore, the movable platen position detector that detects the position of the movable platen 120 and the movable platen movement speed detector that detects the movement speed of the movable platen 120 are not limited to the mold clamping motor encoder 161, and general types can be used.

[0034] In the pressure increasing step, the mold clamping motor 160 is further driven to move the crosshead 151 further forward from the mold closing completion position to the mold clamping position, thereby generating a mold clamping force.

[0035] In the mold clamping process, the mold clamping motor 160 is driven to maintain the position of the crosshead 151 at the mold clamping position. In the mold clamping process, the mold clamping force generated in the pressure increase process is maintained. In the mold clamping process, 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 liquid molding material. The filled molding material is solidified to obtain a molded product.

[0036] The number of cavity spaces 801 may be one or more. In the latter case, multiple molded products are obtained at the same time. An insert material may be placed in a part of the cavity space 801, and another part of the cavity space 801 may be filled with a molding material. A molded product is obtained in which the insert material and the molding material are integrated.

[0037] In the depressurization process, the mold clamping motor 160 is driven to move the crosshead 151 back from the mold clamping position to the mold opening start position, thereby moving the movable platen 120 back and reducing the mold clamping force. The mold opening start position and the mold closing completion position may be the same position.

[0038] In the mold opening process, the mold clamping motor 160 is driven to move the crosshead 151 backward at a set moving speed from the mold opening start position to the mold opening completion position, thereby moving the movable platen 120 backward and separating the movable mold 820 from the fixed mold 810. Thereafter, the ejector unit 200 ejects the molded product from the movable mold 820.

[0039] The setting conditions for the mold closing process, pressure increase process, and mold clamping process are set together as a series of setting conditions. For example, the movement speed and position of the crosshead 151 in the mold closing process and pressure increase process (including the mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position), and the mold clamping force are set together as a series of setting conditions. The mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position are arranged in this order from the rear side to the front, and represent the start and end points of the section for which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching position does not have to be set. Only one of the mold clamping position and the mold clamping force may be set.

[0040] The setting conditions for the depressurization process and mold opening process are also set in a similar manner. For example, the movement speed and position of the crosshead 151 in the depressurization process and mold opening process (mold opening start position, movement speed switching position, and mold opening completion position) are set together as a series of setting conditions. The mold opening start position, movement speed switching position, and mold opening completion position are arranged in this order from the front to the rear, and represent the start and end points of the section for which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching position does not have to be set. The mold opening start position and mold closing completion position may be the same position. Furthermore, the mold opening completion position and mold closing start position may be the same position.

[0041] It should be noted that the moving speed and position of the movable platen 120 may be set instead of the moving speed and position of the crosshead 151. Furthermore, the clamping force may be set instead of the position of the crosshead (for example, the clamping position) or the position of the movable platen.

[0042] The toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 and transmits it to the movable platen 120. The amplification factor is also called the toggle factor. The toggle factor changes depending on the angle θ between the first link 152 and the second link 153 (hereinafter also referred to as the "link angle θ"). The link angle θ is determined from the position of the crosshead 151. When the link angle θ is 180°, the toggle factor is maximum.

[0043] When the thickness of the mold device 800 changes due to replacement of the mold device 800 or a temperature change in the mold device 800, a mold thickness adjustment is performed so that a predetermined clamping force is obtained during mold clamping. In mold thickness adjustment, for example, the distance L between the fixed platen 110 and the toggle support 130 is adjusted so that the link angle θ of the toggle mechanism 150 becomes a predetermined angle at the time of mold touch when the movable mold 820 touches the fixed mold 810.

[0044] The mold clamping unit 100 has a mold thickness adjustment mechanism 180. The mold thickness adjustment mechanism 180 adjusts the mold thickness by adjusting the distance L between the fixed platen 110 and the toggle support 130. The mold thickness adjustment is performed, for example, between the end of a molding cycle and the start of the next molding cycle. The mold thickness adjustment mechanism 180 has, for example, a screw shaft 181 formed at the rear end of the tie bar 140, a screw nut 182 held rotatably and immovably by the toggle support 130, and a mold thickness adjustment motor 183 that rotates the screw nut 182 that is threaded onto the screw shaft 181.

[0045] A screw shaft 181 and a screw nut 182 are provided for each tie bar 140. The rotational driving force of the mold thickness adjustment motor 183 may be transmitted to the plurality of screw nuts 182 via a rotational driving force transmission unit 185. The plurality of screw nuts 182 can be rotated synchronously. Note that by changing the transmission path of the rotational driving force transmission unit 185, the plurality of screw nuts 182 can also be rotated individually.

[0046] The rotational drive force transmission unit 185 is configured with, for example, gears. In this case, a driven gear is formed on the outer periphery of each screw nut 182, a drive gear is attached to the output shaft of the mold thickness adjustment motor 183, and an intermediate gear that meshes with the multiple driven gears and drive gear is rotatably held in the center of the toggle support 130. Note that the rotational drive force transmission unit 185 may be configured with a belt, pulleys, or the like instead of gears.

[0047] The operation of the mold thickness adjustment mechanism 180 is controlled by a control device 700. The control device 700 drives a mold thickness adjustment motor 183 to rotate the screw nut 182. As a result, the position of the toggle support 130 relative to the tie bar 140 is adjusted, and the distance L between the fixed platen 110 and the toggle support 130 is adjusted. Note that a plurality of mold thickness adjustment mechanisms may be used in combination.

[0048] The gap L is detected using a mold thickness adjustment motor encoder 184. The mold thickness adjustment motor encoder 184 detects the amount and direction of rotation of the mold thickness adjustment motor 183, and sends a signal indicating the detection result to the control device 700. The detection result of the mold thickness adjustment motor encoder 184 is used to monitor and control the position of the toggle support 130 and the gap L. Note that the toggle support position detector that detects the position of the toggle support 130 and the gap detector that detects the gap L are not limited to the mold thickness adjustment motor encoder 184, and general detectors can be used.

[0049] The mold clamping unit 100 may have a mold temperature regulator that regulates the temperature of the mold device 800. The mold device 800 has a flow path for a temperature regulation medium inside. The mold temperature regulator regulates the temperature of the mold device 800 by regulating the temperature of the temperature regulation medium supplied to the flow path of the mold device 800.

[0050] Although the mold clamping unit 100 of this embodiment is a horizontal type in which the mold opening and closing direction is horizontal, it may also be a vertical type in which the mold opening and closing direction is vertical.

[0051] Although the mold clamping unit 100 of this embodiment has a mold clamping motor 160 as a drive unit, it may have a hydraulic cylinder instead of the mold clamping motor 160. Also, the mold clamping unit 100 may have a linear motor for opening and closing the mold, and an electromagnet for mold clamping.

[0052] (Ejector device) In describing the ejector device 200, similar to the description of the mold clamping device 100, the direction of movement of the movable platen 120 when the mold is closed (e.g., the positive direction of the X-axis) is defined as the front, and the direction of movement of the movable platen 120 when the mold is opened (e.g., the negative direction of the X-axis) is defined as the rear.

[0053] The ejector unit 200 is attached to the movable platen 120 and moves forward and backward together with the movable platen 120. The ejector unit 200 has an ejector rod 210 that ejects a molded product from the mold device 800, and a drive mechanism 220 that moves the ejector rod 210 in the movement direction of the movable platen 120 (X-axis direction).

[0054] The ejector rod 210 is arranged so as to be able to move forward and backward in a through-hole of the movable platen 120. The front end of the ejector rod 210 contacts an ejector plate 826 of the movable mold 820. The front end of the ejector rod 210 may or may not be connected to the ejector plate 826.

[0055] The drive mechanism 220 includes, for example, an ejector motor and a motion conversion mechanism that converts the rotational motion of the ejector motor into linear motion of the ejector rod 210. The motion conversion mechanism includes a screw shaft and a screw nut that screws onto the screw shaft. Balls or rollers may be interposed between the screw shaft and the screw nut.

[0056] The ejector unit 200 performs an ejection process under the control of the control unit 700. In the ejection process, the ejector rod 210 is advanced from the standby position to the ejection position at a set moving speed, thereby advancing the ejector plate 826 and ejecting the molded product. After that, the ejector motor is driven to retract the ejector rod 210 at the set moving speed, and the ejector plate 826 is retracted to the original standby position.

[0057] The position and movement speed of the ejector rod 210 are detected 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. Note that the ejector rod position detector that detects the position of the ejector rod 210 and the ejector rod movement speed detector that detects the movement speed of the ejector rod 210 are not limited to the ejector motor encoder, and general types can be used.

[0058] (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 movement direction of the screw 330 during filling (e.g., the negative X-axis direction) is described as the forward direction, and the movement direction of the screw 330 during metering (e.g., the positive X-axis direction) is described as the rearward direction.

[0059] The injection unit 300 is mounted on a slide base 301, and the slide base 301 is disposed so as to be able to move forward and backward relative to the injection unit frame 920. The injection unit 300 is disposed so as to be able to move forward and backward relative to the mold unit 800. The injection unit 300 touches the mold unit 800 and fills a cavity space 801 in the mold unit 800 with a molding material. The injection unit 300 includes, for example, a cylinder 310 that heats the molding material, a nozzle 320 provided at the front end of the cylinder 310, a screw 330 that is disposed so as to be able to move forward and backward and to be able to rotate within the cylinder 310, a metering motor 340 that rotates the screw 330, an injection motor 350 that moves the screw 330 forward and backward, and a load detector 360 that detects a load transmitted between the injection motor 350 and the screw 330.

[0060] Cylinder 310 heats the molding material supplied to the interior through supply port 311. The molding material includes, for example, resin. The molding material is formed, for example, in the form of pellets and supplied to supply port 311 in a solid state. Supply port 311 is formed at the rear of cylinder 310. A cooler 312, such as a water-cooled cylinder, is provided on the outer periphery of the rear of cylinder 310. A first heater 313, such as a band heater, and a first temperature detector 314 are provided on the outer periphery of cylinder 310, ahead of cooler 312.

[0061] Cylinder 310 is divided into a plurality of zones in the axial direction (e.g., X-axis direction) of cylinder 310. A first heater 313 and a first temperature detector 314 are provided in each of the plurality of zones. A set temperature is set in each of the plurality of zones, and control device 700 controls first heater 313 so that the temperature detected by first temperature detector 314 becomes the set temperature.

[0062] The nozzle 320 is provided at the front end of the cylinder 310 and is pressed against the mold device 800. A second heater 323 and a second temperature detector 324 are provided on the outer periphery of the nozzle 320. The control device 700 controls the second heater 323 so that the detected temperature of the nozzle 320 becomes the set temperature.

[0063] The screw 330 is disposed within the cylinder 310 so as to be rotatable and movable forward and backward. When the screw 330 is rotated, the molding material is sent forward along the spiral groove of the screw 330. As the molding material is sent forward, it is gradually melted by the heat from the cylinder 310. As the liquid molding material is sent forward to the front of the screw 330 and accumulates in the front part of the cylinder 310, the screw 330 is moved backward. Thereafter, when the screw 330 is moved forward, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled into the mold device 800.

[0064] A backflow prevention ring 331 is attached to the front of the screw 330 so as to be movable back and forth as a backflow prevention valve for preventing the molding material from flowing back from the front to the rear of the screw 330 when the screw 330 is pushed forward.

[0065] When the screw 330 is moved forward, the backflow prevention ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and moves back relative to the screw 330 to a blocking position (see FIG. 2) where it blocks the flow path of the molding material. This prevents the molding material accumulated in front of the screw 330 from flowing backward.

[0066] On the other hand, when the screw 330 is rotated, 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, and moves forward relative to the screw 330 to the open position (see FIG. 1) where it opens the flow path of the molding material. This causes the molding material to be sent forward of the screw 330.

[0067] The backflow prevention ring 331 may be either a co-rotating type that rotates together with the screw 330 or a non-co-rotating type that does not rotate together with the screw 330.

[0068] The injection device 300 may have a drive source for moving the backflow prevention ring 331 back and forth relative to the screw 330 between the open position and the closed position.

[0069] 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.

[0070] The injection motor 350 advances and retreats the screw 330. A motion conversion mechanism that converts the rotational motion of the injection motor 350 into linear motion of the screw 330 is provided between the injection motor 350 and the screw 330. The motion conversion mechanism has, for example, a screw shaft and a screw nut that screws onto the screw shaft. A ball or roller may be provided between the screw shaft and the screw nut. The drive source that advances and retreats the screw 330 is not limited to the injection motor 350 and may be, for example, a hydraulic cylinder.

[0071] The load detector 360 detects the load transmitted between the injection motor 350 and the screw 330. The detected load is converted into pressure by the control device 700. The load detector 360 is provided on the load transmission path between the injection motor 350 and the screw 330, and detects the load acting on the load detector 360.

[0072] The load detector 360 sends a signal of the detected load to the control device 700. The load detected by the load detector 360 is converted into pressure acting between the screw 330 and the molding material, and is used to control and monitor the pressure that the screw 330 receives from the molding material, the back pressure on the screw 330, the pressure that the screw 330 acts on the molding material, and the like.

[0073] The pressure detector for detecting the pressure of the molding material is not limited to the load detector 360, and a general detector can be used. For example, a nozzle pressure sensor or a mold internal pressure sensor may be used. The nozzle pressure sensor is installed in the nozzle 320. The mold internal pressure sensor is installed inside the mold device 800.

[0074] The injection device 300 performs a metering process, a filling process, a pressure holding process, etc. under the control of the control device 700. The filling process and the pressure holding process may be collectively referred to as the injection process.

[0075] In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is sent forward along the spiral groove of the screw 330. As this happens, the molding material gradually melts. As the liquid molding material is sent forward to the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is moved backward. 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 the detection result to the control device 700. Note that the screw rotational speed detector that detects the rotational speed of the screw 330 is not limited to the metering motor encoder 341, and a general one can be used.

[0076] In the metering process, in order to restrict abrupt retraction of the screw 330, the injection motor 350 may be driven to apply a set back pressure to the screw 330. The back pressure on the screw 330 is detected using, for example, a load detector 360. When the screw 330 retracts to the metering completion position and a predetermined amount of molding material accumulates in front of the screw 330, the metering process is completed.

[0077] The position and rotational speed of the screw 330 in the metering process are set together as a series of setting conditions. For example, a metering start position, a rotational speed switching position, and a metering completion position are set. These positions are arranged in this order from the front to the rear, and represent the start and end points of the section for which the rotational speed is set. The rotational speed is set for each section. There may be one or more rotational speed switching positions. The rotational speed switching position does not have to be set. In addition, a back pressure is set for each section.

[0078] In the filling process, the injection motor 350 is driven to move the screw 330 forward at a set moving speed, and the liquid molding material accumulated in front of the screw 330 is filled into the cavity space 801 in the mold device 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 a set position, a switch from the filling process to a pressure holding process (so-called V / P switch) is performed. The position at which the V / P switch is performed is also called the V / P switch position. The set moving speed of the screw 330 may be changed depending on the position of the screw 330, time, etc.

[0079] The position and movement speed of the screw 330 in the filling process are set together as a series of setting conditions. For example, a filling start position (also called an "injection start position"), a movement speed switching position, and a V / P switching position are set. These positions are arranged in this order from rear to front, and represent the start and end points of the section for which the movement speed is set. The movement speed is set for each section. There may be one or more movement speed switching positions. The movement speed switching position does not have to be set.

[0080] An upper limit value for the pressure of the screw 330 is set for each section in which the movement speed of the screw 330 is set. The pressure of the screw 330 is detected by a load detector 360. When the pressure of the screw 330 is equal to or lower than the set pressure, the screw 330 is advanced at the set movement speed. On the other hand, when the pressure of the screw 330 exceeds the set pressure, the screw 330 is advanced at a movement speed slower than the set movement speed so that the pressure of the screw 330 is equal to or lower than the set pressure, in order to protect the mold.

[0081] Note that after the position of the screw 330 reaches the V / P switching position during the filling process, the screw 330 may be temporarily stopped at the V / P switching position, and then V / P switching may be performed. Immediately before V / P switching, instead of stopping the screw 330, the screw 330 may be moved forward or backward at a slow speed. Furthermore, the screw position detector that detects the position of the screw 330 and the screw movement speed detector that detects the movement speed of the screw 330 are not limited to the injection motor encoder 351, and general detectors may be used.

[0082] In the dwelling step, the injection motor 350 is driven to push 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 toward the mold device 800. This can replenish any molding material that is insufficient due to cooling contraction within the mold device 800. The holding pressure is detected, for example, using a load detector 360. The set value of the holding pressure may be changed depending on the elapsed time from the start of the dwelling step, etc. Multiple holding pressures and holding times for maintaining the holding pressure in the dwelling step may be set, or they may be set together as a series of setting conditions.

[0083] In the dwelling step, the molding material in the cavity space 801 in the mold device 800 is gradually cooled, and when the dwelling step is completed, the entrance to the cavity space 801 is blocked by the solidified molding material. This state is called a gate seal, and prevents the molding material from flowing back from the cavity space 801. After the dwelling step, the cooling step begins. In the cooling step, the molding material in the cavity space 801 is solidified. A metering step may be performed during the cooling step in order to shorten the molding cycle time.

[0084] The injection device 300 of this embodiment is of an in-line screw type, but may also be of a pre-plasticization type. A pre-plasticization type injection device supplies molding material molten in a plasticization cylinder to an injection cylinder, and injects the molding material from the injection cylinder into a mold device. A screw is disposed in the plasticization cylinder so that it can rotate freely but cannot move back and forth, or the screw is disposed so that it can rotate freely and move back and forth. Meanwhile, a plunger is disposed in the injection cylinder so that it can move back and forth.

[0085] Furthermore, although the injection unit 300 of this embodiment is a horizontal type in which the axial direction of the cylinder 310 is horizontal, it may be a vertical type in which the axial direction of the cylinder 310 is vertical. The mold clamping unit combined with the vertical injection unit 300 may be either a vertical type or a horizontal type. Similarly, the mold clamping unit combined with the horizontal injection unit 300 may be either a horizontal type or a vertical type.

[0086] (Mobile device) In the description of the moving device 400, similar to the description of the injection device 300, the moving direction of the screw 330 during filling (e.g., the negative X-axis direction) is defined as the front, and the moving direction of the screw 330 during metering (e.g., the positive X-axis direction) is defined as the rear.

[0087] The moving device 400 moves the injection device 300 forward and backward relative to the mold device 800. The moving device 400 also presses the nozzle 320 against the mold device 800 to generate 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.

[0088] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectional pump, and by switching the rotation direction of the motor 420, it draws in hydraulic fluid (e.g., oil) from one of the first port 411 and the second port 412 and discharges it from the other, thereby generating hydraulic pressure. Note that the hydraulic pump 410 can also draw in hydraulic fluid from a tank and discharge it from either the first port 411 or the second port 412.

[0089] The motor 420 operates the hydraulic pump 410. The motor 420 drives the hydraulic pump 410 in a rotational direction and with a rotational torque according to a control signal from the control device 700. The motor 420 may be an electric motor or an electric servo motor.

[0090] 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 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed to the fixed platen 110.

[0091] A front chamber 435 of the hydraulic cylinder 430 is connected to a first port 411 of the hydraulic pump 410 via a first flow path 401. The hydraulic fluid discharged from the first port 411 is supplied to the front chamber 435 via the first flow path 401, thereby pushing the injection unit 300 forward. The injection unit 300 is moved forward, and the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber that generates nozzle touch pressure of the nozzle 320 by the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

[0092] Meanwhile, 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, thereby pushing the injection unit 300 backward. The injection unit 300 is moved backward, and the nozzle 320 is separated from the fixed mold 810.

[0093] In this 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 the linear motion of the injection device 300 may be used.

[0094] (Control device) The control device 700 is configured, for example, by a computer, and as shown in Figures 1 and 2, has 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 causing the CPU 701 to execute a program stored in the storage medium 702. The control device 700 also receives signals from the outside via the input interface 703 and transmits signals to the outside via the output interface 704.

[0095] The control device 700 repeatedly manufactures molded products by repeating processes such as a metering process, mold closing process, pressure increase process, mold clamping process, filling process, pressure dwell process, cooling process, pressure release process, mold opening process, and ejection process. A series of operations required to obtain a molded product, such as the operations from the start of a metering process to the start of the next metering process, is also called a "shot" or "molding cycle." The time required for one shot is also called the "molding cycle time" or "cycle time."

[0096] One molding cycle includes, for example, a metering process, a mold closing process, a pressurization process, a mold clamping process, a filling process, a pressure holding process, a cooling process, a depressurization process, a mold opening process, and an ejection process, in this order. The order here refers to the order in which each process starts. The filling process, the pressure holding process, and the cooling process are performed during the mold clamping process. The start of the mold clamping process may coincide with the start of the filling process. The completion of the depressurization process coincides with the start of the mold opening process.

[0097] In addition, multiple processes may be performed simultaneously in order to shorten the molding cycle time. For example, the metering process may be performed during the cooling process of the previous molding cycle, or during the mold clamping process. In this case, the mold closing process may be performed at the beginning of the molding cycle. The filling process may be started during the mold closing process. The ejection process may be started during the mold opening process. If an on-off valve that opens and closes the flow path of the nozzle 320 is provided, the mold opening process may be started during the metering process. This is because even if the mold opening process is started during the metering process, the molding material will not leak from the nozzle 320 as long as the on-off valve closes the flow path of the nozzle 320.

[0098] Note that one molding cycle may include steps other than the metering step, mold closing step, pressure increase step, mold clamping step, filling step, pressure holding step, cooling step, pressure release step, mold opening step, and ejection step.

[0099] For example, after the dwelling step is completed and before the metering step begins, a pre-metering suck-back step may be performed in which the screw 330 is retracted to a preset metering start position. This can reduce the pressure of the molding material accumulated in front of the screw 330 before the metering step begins, and prevent the screw 330 from retracting suddenly at the start of the metering step.

[0100] Furthermore, after the metering step is completed and before the filling step begins, a post-metering suck-back step may be performed in which the screw 330 is retracted to a preset filling start position (also referred to as the "injection start position"). This can reduce the pressure of the molding material accumulated in front of the screw 330 before the filling step begins, and can prevent the molding material from leaking from the nozzle 320 before the filling step begins.

[0101] The control device 700 is connected to an operation device 750 that accepts input operations by a user and a display device 760 that displays a screen. The operation device 750 and the display device 760 may be integrated, for example, by using a touch panel 770. The touch panel 770 serving as the display device 760 displays a screen under the control of the control device 700. The screen of the touch panel 770 may display information such as settings of the injection molding machine 10 and the current status of the injection molding machine 10. The screen of the touch panel 770 may also display operation units such as buttons and input fields that accept input operations by the user. The touch panel 770 serving as the operation device 750 detects input operations on the screen by the user and outputs signals corresponding to the input operations to the control device 700. This allows, for example, a user to operate the operation units provided on the screen while checking information displayed on the screen to perform settings of the injection molding machine 10 (including input of setting values). The user can also operate the operation units provided on the screen to cause the injection molding machine 10 to perform operations corresponding to the operation units. The operation of the injection molding machine 10 may be, for example, the operation (including stopping) of the clamping device 100, the ejector device 200, the injection device 300, the moving device 400, etc. The operation of the injection molding machine 10 may also be the switching of a screen displayed on the touch panel 770 serving as the display device 760, etc.

[0102] Although the operation device 750 and the display device 760 of this embodiment have been described as being integrated as the touch panel 770, they may be provided independently. Also, a plurality of operation devices 750 may be provided. The operation device 750 and the display device 760 are disposed on the operation side (negative Y-axis direction) of the mold clamping unit 100 (more specifically, the fixed platen 110).

[0103] (Tie bar 140 configuration) Next, the configuration of the tie bar 140 according to this embodiment will be described with reference to Figures 3 and 4. Figure 3 is a diagram schematically showing the support side of the fixed mold 810 in the mold clamping unit 100, where (A) is a cross-sectional view taken along line III-III in Figure 1 and (B) is a side view. Figure 4 is a diagram showing the attachment of the heat limiting portion 142 to the tie bar 140, where (A) is a perspective view and (B) is a diagram showing the operation during attachment.

[0104] As described above, the mold clamping unit 100 of the injection molding machine 10 includes four tie bars 140 extending between the fixed platen 110 and the toggle support 130 (see FIG. 1). Each of the four tie bars 140 is disposed at one of the four corners of the fixed platen 110 and one of the four corners of the toggle support 130. Each tie bar 140 is inserted into a hole in the fixed platen 110 and is firmly fixed by a fixing structure 146 on the rear side of the fixed platen 110.

[0105] The tie bars 140 are formed, for example, in a circular shape with a predetermined diameter in a cross section perpendicular to the mold opening / closing direction. The tie bars 140 extend linearly while maintaining this diameter.

[0106] On the other hand, the movable platen 120 (see FIG. 1) has through holes or notches (not shown) at its four corners through which the tie bars 140 extending between the fixed platen 110 and the toggle support 130 pass.

[0107] A fixed mold 810 of the mold device 800 is provided in the center of the fixed platen 110 (between the four tie bars 140). The fixed mold 810 is disposed at a position spaced apart from the tie bars 140 and in a non-contact state with the tie bars 140. Note that, although the fixed mold 810 has a square shape in a cross section perpendicular to the mold opening / closing direction (FIG. 3(A)), it may be formed in another shape, such as a rectangular shape that is elongated in the vertical or horizontal direction. Furthermore, although not shown, a movable mold 820 of the mold device 800 is provided in the center of the movable platen 120 (between the four tie bars 140) so as to face the fixed mold 810.

[0108] The mold assembly 800 includes a temperature control mechanism 811 that controls the temperature of the fixed mold 810. The temperature control mechanism 811 includes a temperature control medium circulator (not shown) and piping 812 (a temperature control medium supply pipe 812a and a temperature control medium discharge pipe 812b) that connects the temperature control medium circulator and the fixed mold 810. The temperature control medium circulator controls the temperature of the temperature control medium and circulates the temperature-controlled temperature control medium through the fixed mold 810. Examples of the temperature control medium that can be used include water, liquid organic matter (oil, etc.), or a mixture of these. The mold assembly 800 may include a temperature control mechanism for the movable mold 820 similar to the temperature control mechanism 811 for the fixed mold 810. The mold assembly 800 is not limited to a configuration that circulates a temperature control medium, and may include a heater inside.

[0109] Each pipe 812 has a flow path therein through which a temperature control medium can flow. The temperature control medium supply pipe 812a supplies the temperature control medium from the temperature control medium circulation device to the fixed mold 810. The temperature control medium discharge pipe 812b returns the temperature control medium discharged from the fixed mold 810 to the temperature control medium circulation device. The pipes 812 are connected, for example, to the horizontal side peripheral surface of the fixed mold 810 and extend in the lateral direction (horizontal direction). That is, the temperature control medium supply pipe 812a and the temperature control medium discharge pipe 812b pass between two tie bars 140 arranged above and below.

[0110] In the injection molding machine 10 configured as described above, the air around the fixed mold 810 is heated to a temperature above room temperature by the fixed mold 810, the temperature control medium supply pipe 812a, and the temperature control medium discharge pipe 812b. Heat generated by the fixed mold 810 is mainly due to the high-temperature resin filled in the fixed mold 810. Heat generated by the piping 812 is mainly due to the circulating temperature control medium. To restrict this heated air from moving to the tie bars 140 (direct contact of the heated air with the tie bars 140), the injection molding machine 10 has a heat limiting portion 142 around the tie bars 140.

[0111] The heat limiting portion 142 is provided on the outer circumferential surface of the tie bar 140, which extends outside the fixed platen 110 and the toggle support 130. The heat limiting portion 142 in the illustrated example is in direct contact with the outer circumferential surface of the tie bar 140 and employs a heat limiting member 143 that covers the entire circumferential circumference of the outer circumferential surface. Although not shown, the tie bar strain detector 141 is attached at an appropriate position on the tie bar 140 so as to be exposed from the heat limiting member 143 that covers the tie bar 140.

[0112] The heat limiting member 143 is made of a heat insulating material that can be wrapped around the outer circumferential surface of the tie bar 140. Examples of the heat insulating material that makes up the heat limiting member 143 include inorganic fibers such as glass wool, glass fiber, and ceramic fiber, or resin materials that contain fibers or porous materials. The heat limiting member 143 may have a layered structure in which multiple layers with different functions are stacked.

[0113] 4(A), the heat limiting member 143 is formed in a cylindrical shape with an inner circumferential surface that substantially matches the outer circumferential surface of the tie bar 140. This heat limiting member 143 may be configured to be elastically deformable so as to fit the outer diameter of the tie bar 140, or may be configured to have a rigidity that allows it to continuously maintain its cylindrical shape. Alternatively, the heat limiting member 143 may be formed in a sheet shape and wrapped around the tie bar 140. The heat limiting member 143 may have a seal structure (not shown) with an adhesive layer on one surface that comes into contact with the outer circumferential surface of the tie bar 140.

[0114] 4(B), the heat limiting member 143 may be provided with an attachment structure 144 that allows a user of the injection molding machine 10 to perform attachment and detachment operations, and may be removably attached to the tie bars 140. This allows the heat limiting member 143 to be removed for work such as when installing the mold apparatus 800 on the fixed platen 110 or the movable platen 120, thereby improving workability. The attachment structure 144 may include, for example, slits 144a formed at predetermined circumferential positions of the heat limiting member 143, and connecting members 144b that connect the heat limiting members 143 between the slits 144a. In other words, the heat limiting member 143 may be configured as an elastic member that is formed with a C-shaped cross section across the slits 144a before installation and maintains that shape.

[0115] The heat limiting member 143 may be formed with a diameter slightly larger than the diameter of the outer circumferential surface of the tie bar 140, and may have a structure in which an air layer is formed between its inner circumferential surface and the outer circumferential surface of the tie bar 140. The air layer may be a space, or a member such as a porous body may be interposed. In other words, the heat limiting part 142 may have a structure in which it is not in contact with (or is in partial contact with) the outer circumferential surface of the tie bar 140.

[0116] The heat limiting portion 142 may also have a structure in which the outer circumferential surface of the tie bar 140 is coated with a heat insulating paint or a heat shielding paint having a thermal conductivity lower than that of the tie bar 140 .

[0117] The heat limiting portion 142 provided on the tie bar 140 has one end portion on the fixed platen 110 side in contact with the fixed platen 110 without any gap. This ensures that the tie bar 140 is not exposed around the fixed mold 810. Note that one end portion of the heat limiting portion 142 may be partially inserted inside the fixed platen 110.

[0118] The heat limiting portion 142 is continuous and extends beyond the fixed mold 810, which protrudes from the fixed platen 110 toward the movable platen 120. The axial extent of the heat limiting portion 142 along the tie bar 140 is not particularly limited. However, it is preferable that the heat limiting portion 142 be provided over the entire area between the fixed platen 110 and the movable platen 120. More specifically, the other end of the heat limiting portion 142 preferably reaches the movable platen 120, which is positioned at the mold closing start position. This ensures that the heat limiting portion 142 can insulate the entire adjacent area between the fixed mold 810 and the movable mold 820 when the mold assembly 800 is in a mold clamping state. By appropriately adjusting the thickness of the heat limiting portion 142, it is possible to prevent the heat limiting portion 142 from contacting the corners of the through-holes and notches of the movable platen 120. This prevents the heat limiting portion 142 from interfering with the mold closing and mold opening operations of the movable platen 120. The heat limiting portion 142 may be thin at a portion that may come into contact with the movable platen 120 as the movable platen 120 moves, and may be thick at a portion that does not come into contact with the movable platen 120 (such as a position near the fixed platen 110). Note that the heat limiting portion 142 may be provided over the entire area between the fixed platen 110 and the toggle support 130.

[0119] The injection molding machine 10 and the heat limiting member 143 according to this embodiment are basically configured as described above, and the operation (heat input limiting method) and effects thereof will be described below.

[0120] Under the control of the control device 700, the injection molding machine 10 performs a metering process, a mold closing process, a pressure increase process, a mold clamping process, a filling process, a pressure holding process, a cooling process, a pressure release process, a mold opening process, and an ejection process during injection molding.

[0121] Furthermore, during injection molding, the mold assembly 800 operates a temperature adjustment mechanism 811 to adjust (heat) the temperature of the fixed mold 810 and the movable mold 820. For example, the temperature adjustment mechanism 811 supplies a temperature adjustment medium to the fixed mold 810 via a temperature adjustment medium supply pipe 812a, and discharges the temperature adjustment medium, which has adjusted the temperature of the fixed mold 810, via a temperature adjustment medium discharge pipe 812b. The temperature-adjusted mold assembly 800 (fixed mold 810) or the pipe 812 through which the temperature adjustment medium flows, heats the surrounding air to above room temperature and causes convection.

[0122] The four tie bars 140 extending adjacent to the mold assembly 800 are affected by this heat. In particular, because the heated air flows upward, the heated air is directed toward the tie bar 140 located above the temperature control medium supply pipe 812a among the four tie bars 140. If the heat limiting member 143 were not provided, the influence of the heat from the mold assembly 800 would be uneven among the four tie bars 140. As a result, differences in axial force (the amount of elongation during mold clamping) would occur among the four tie bars 140.

[0123] The injection molding machine 10 according to this embodiment is provided with a heat limiting portion 142 on each of the four tie bars 140 extending outside the fixed platen 110. The heat limiting portion 142 limits the transfer of heat from the air heated by the mold assembly 800 or the piping 812 to the tie bars 140, thereby reducing the heat input to the tie bars 140. This enables the injection molding machine 10 to stabilize the axial force of the tie bars 140, and allows for good mold clamping between the fixed mold 810 and the movable mold 820, etc.

[0124] In particular, by providing each heat limiting portion 142 on each of the four tie bars 140, it is possible to easily accommodate the direction of heat input from the air, which varies depending on the shapes of the fixed mold 810 and movable mold 820, the arrangement of the piping 812, and the like. Furthermore, each heat limiting portion 142 suppresses heat transfer within itself, thereby reducing the difference in the amount of heat input that reaches each tie bar 140. Therefore, the injection molding machine 10 can align the axial forces of the four tie bars 140 when clamping the molds for injection molding, allowing for more stable injection molding.

[0125] Furthermore, by applying a heat limiting member 143 designed in advance to fit the outer circumferential surface of the tie bar 140 as the heat limiting unit 142, the injection molding machine 10 can simplify the attachment and detachment of the heat limiting unit 142 to the tie bar 140. Therefore, even when the heat limiting unit 142 is applied, it is possible to efficiently attach and detach the mold device 800 and perform maintenance of the injection molding machine 10. Furthermore, it is preferable that the heat limiting unit 142 is fixed to the tie bar 140 so as not to expand or contract.

[0126] Furthermore, the heat limiting portion 142 is provided continuously along the entire axial direction of the tie bar 140 from the fixed platen 110 to the movable platen 120, thereby suppressing the influence of heat on the mold device 800 over a sufficient axial length. At the same time, the tie bar 140 can be firmly fixed inside the fixed platen 110.

[0127] Furthermore, the heat limiting portion 142 arranged between the fixed mold 810 or the movable mold 820 and the tie bar 140 can stably limit the heat of the fixed mold 810 or the movable mold 820 from being transferred to the tie bar 140. Similarly, the heat limiting portion 142 arranged between the piping 812 and the tie bar 140 can stably limit the heat of the piping 812 from being transferred to the tie bar 140.

[0128] The injection molding machine 10 according to this embodiment is not limited to the above embodiment and may take various modified forms. For example, in the above embodiment, a configuration has been described in which all four tie bars 140 are provided with heat limiting units 142. However, the heat limiting units 142 may be provided on tie bars 140 that are more susceptible to heat, while not necessarily provided on tie bars 140 that are less susceptible to heat. For example, in FIG. 3(A), a configuration may be adopted in which the heat limiting unit 142 is provided only on the upper left tie bar 140.

[0129] FIG. 5 is a schematic diagram illustrating a heat limiting unit according to a modified example. As shown in FIG. 5, the injection molding machine 10 may be configured such that a shielding member 145 is disposed as the heat limiting unit 142 between the mold assembly 800 and each tie bar 140. The shielding member 145 is formed, for example, in a plate shape and fixed to a stationary platen 110 or the like. Note that while the shielding member 145 in FIG. 5 is an arc-shaped plate, the shape of the shielding member 145 is not limited thereto and may be, for example, a flat plate. In this way, even if the shielding member 145 is disposed at a position spaced apart from the outer circumferential surface of the tie bar 140 and between the mold assembly 800 and the piping 812, the injection molding machine 10 can restrict the movement of air heated by the mold assembly 800 to the tie bar 140.

[0130] The injection molding machine 10, the thermal limiting member, and the heat input suppression method according to the presently disclosed embodiments are illustrative in all respects and are not limiting. The embodiments may be modified and improved in various ways without departing from the spirit and scope of the appended claims. The features described in the above embodiments may be configured differently and may be combined within a consistent range. [Explanation of symbols]

[0131] 10 injection molding machine 110 Fixed Platen 120 Movable Platen 140 tie bar 142 Heat limiting section 810 Fixed mold 820 Movable mold

Claims

1. An injection molding machine in which a movable platen on which a fixed mold is installed is moved along tie bars relative to a fixed platen on which a fixed mold is installed to open and close the fixed mold and the movable mold, a heat limiting portion that limits the movement of air heated to a temperature above room temperature around the tie bar to the tie bar; the heat limiting unit has a shielding unit provided between the fixed mold or the movable mold and the tie bar, and exposes the tie bar to the outside on the opposite side of the shielding unit across the tie bar. Injection molding machine.

2. the heat limiting portion is provided on a portion of the tie bar that is exposed from the fixed platen.

2. The injection molding machine according to claim 1.

3. The heat limiting portion is disposed between the fixed mold or the movable mold and the tie bar.

3. The injection molding machine according to claim 1 or 2.

4. the heat limiting unit is disposed between the tie bar and a pipe that supplies and discharges a temperature control medium to and from the inside of the fixed mold or the movable mold.

4. The injection molding machine according to claim 1.

5. A thermal limiting member attached to an injection molding machine that opens and closes the fixed mold and the movable mold by moving a movable platen, on which a fixed mold is installed, along tie bars relative to a fixed platen, on which a fixed mold is installed, The thermal limiting member is a shielding portion disposed between the fixed mold or the movable mold and the tie bar, and the tie bar is exposed to the outside on the opposite side of the shielding portion with the tie bar sandwiched therebetween; When the air conditioner is attached to the tie bar, the air heated to a temperature equal to or higher than room temperature around the tie bar is restricted from moving to the tie bar. Thermal limiting member.

6. 1. A heat input suppression method for an injection molding machine in which a movable platen on which a fixed mold is installed is moved along tie bars relative to a fixed platen on which a fixed mold is installed to open and close the fixed mold and the movable mold, the method comprising: a shielding part is disposed between the fixed mold or the movable mold and the tie bar, and a heat limiting part is attached on the opposite side of the tie bar from the shielding part, exposing the tie bar to the outside; The heat limiting portion limits the movement of air heated to a temperature higher than room temperature around the tie bar to the tie bar. Heat input suppression method.

Images