Injection molding machine

Abstract

An injection molding machine according to the present invention comprises an injection device that fills a molding material into a die device, and a control device that controls the injection device. The injection device comprises a cylinder that heats the molding material, a screw disposed inside of the cylinder, and a metering motor that rotates the screw. The control device has a correction control unit which, on the basis of the circumferential directional position of the screw which varies on the basis of the operation of the metering motor, corrects a pressure setting value used in pressure control of the screw, or corrects a detection value output from a pressure detector that detects the pressure acting on the screw.

Description

[Technical field]

[0001] The present invention relates to an injection molding machine. [Background technology]

[0002] The injection molding machine includes a cylinder to which resin pellets as a molding material are supplied, and a heater to heat the cylinder to melt the resin pellets. The injection molding machine manufactures a molded product by melting the resin pellets in the cylinder and filling the cavity space in a mold device with the molten resin.

[0003] Injection molding machines are equipped with various sensors, and it is desirable to recognize accurate torque and stress from values ​​detected by the sensors. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2009-045904 A Summary of the Invention [Problem to be solved by the invention]

[0005] In Patent Document 1, the rotational torque during metering is measured and stored, and then input into a pre-determined function to set the allowable upper limit of the screw rotational torque, thereby enabling torque monitoring based on the allowable upper limit without complex calculations of the material mechanical strength.

[0006] On the other hand, in order to properly control and monitor the injection molding machine, it is desirable to detect not only the rotation torque but also the resin pressure accurately. However, the friction of the drive parts and the offset load caused by the change in posture affect the detection value of the load detector.

[0007] One aspect of the present invention provides a technique for improving the accuracy of pressure control for filling a molding material and the accuracy of detection of the pressure acting on a screw. [Means for solving the problem]

[0008] According to one aspect of the present invention, there is provided an injection molding machine including an injection device for filling a mold device with a molding material, and a control device for controlling the injection device. The injection device includes a cylinder for heating the molding material, a screw disposed in the cylinder, and a metering motor for rotating the screw. The control device includes 、 Metering motor Rotation angle The pressure setting value used for controlling the pressure of the screw is corrected based on the pressure setting value, or the detection value output from a pressure detector that detects the pressure acting on the screw is corrected.

[0009] According to one aspect of the present invention, there is provided an injection molding machine including an injection device that fills a mold device with a molding material, and a control device that controls the injection device. The injection device includes a cylinder that heats the molding material, a screw disposed in the cylinder, and A metering motor that rotates the screw; The control device has , weighing Motor The detected value of the encoder The pressure setting value used for controlling the pressure of the screw is corrected based on the pressure setting value, or the detection value output from a pressure detector that detects the pressure acting on the screw is corrected.

[0010] An injection molding machine according to one aspect of the present invention comprises: The injection device has an injection device that fills a mold device with molding material, and a control device that controls the injection device, and the injection device has a cylinder that heats the molding material, a screw arranged in the cylinder, a metering motor that rotates the screw, an injection motor connected to an injection spline shaft, and a pressure detector that outputs a detection value that is the detection result of the pressure acting on the screw, and the control device has a correction control unit that corrects the pressure set value used to control the screw pressure in response to changes in the detection value that changes according to the phase of the injection spline shaft based on the rotation angle of the injection motor, or corrects the detection value output from the pressure detector. In addition, an injection molding machine according to one embodiment of the present invention has an injection device that fills a mold device with molding material and a control device that controls the injection device, and the injection device has a cylinder that heats the molding material, a screw arranged in the cylinder, a metering motor that rotates the screw, an injection motor connected to the injection spline shaft, and a pressure detector that outputs a detection value that is the detection result of the pressure acting on the screw, and the control device has a correction control unit that corrects the pressure set value used to control the screw pressure in response to changes in the detection value that changes depending on the axial position of the injection spline shaft based on the rotation angle of the injection motor, or corrects the detection value output from the pressure detector. In addition, an injection molding machine according to one embodiment of the present invention has an injection device that fills a mold device with molding material and a control device that controls the injection device, and the injection device has a cylinder that heats the molding material, a screw arranged in the cylinder, a metering motor that rotates the screw, an injection motor connected to the injection spline shaft, and a pressure detector that outputs a detection value that is the detection result of the pressure acting on the screw, and the control device has a correction control unit that corrects the pressure set value used to control the screw pressure in response to changes in the detection value that changes depending on the axial position of the injection spline shaft based on the detection value of the encoder of the injection motor, or corrects the detection value output from the pressure detector. In addition, an injection molding machine according to one embodiment of the present invention has an injection device that fills a mold device with molding material and a control device that controls the injection device, and the injection device has a cylinder that heats the molding material, a screw arranged in the cylinder, a metering motor that rotates the screw, an injection motor connected to the injection spline shaft, and a pressure detector that outputs a detection value that is the detection result of the pressure acting on the screw, and the control device has a correction control unit that corrects the pressure set value used to control the screw pressure in response to changes in the detection value that changes depending on the axial position of the injection spline shaft based on the detection value of the encoder of the injection motor, or corrects the detection value output from the pressure detector. Effect of the Invention

[0011] According to one aspect of the present invention, the influence of disturbances is suppressed, and the accuracy of pressure control for filling a molding material and the accuracy of detection of the pressure acting on a screw are improved. [Brief description of the drawings]

[0012] [Figure 1]FIG. 1 is a diagram showing a state when mold opening of an injection molding machine according to an embodiment is completed. [Diagram 2] FIG. 2 is a diagram showing a state during mold clamping of the injection molding machine according to one embodiment. [Diagram 3] FIG. 3 is a diagram showing a state at the start of injection of the injection device according to one embodiment. [Figure 4] FIG. 4 is a diagram showing a state when the injection device according to one embodiment has completed injection. [Diagram 5] FIG. 5 is a partially enlarged view of the injection device according to one embodiment in a state where injection is completed. [Figure 6] FIG. 6 is a functional block diagram illustrating components of a control device according to an embodiment. [Figure 7] FIG. 7 is a conceptual diagram showing the pressure detected by the load detector during weighing in the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating an example of the relationship between a detection value by the load detector according to the first embodiment and a force due to resin pressure. [Figure 9] FIG. 9 is a diagram showing detection values ​​detected by the load detector when the injection spline shaft is moved while the circumferential position of the screw according to the first embodiment is fixed. [Figure 10] FIG. 10 is a diagram illustrating a table of the correction information storage unit registered in the registration unit according to the first embodiment. [Figure 11] FIG. 11 is a flowchart showing a process for registering a correction value in the correction information storage unit in the control device according to the first embodiment. [Figure 12] FIG. 12 is a flowchart showing a display process performed during measurement in the control device according to the first embodiment. [Figure 13] FIG. 13 is a diagram illustrating an example of resistance (including friction) that changes depending on the circumferential position (rotation angle) of the screw or the position of the screw (phase of the injection spline shaft). [Figure 14] FIG. 14 is a diagram showing the structure of a speed correction value storage table held by a correction information storage unit according to the second embodiment. [Figure 15] FIG. 15 is a diagram illustrating an example of fluctuations in the correction value calculated by the correction control unit according to the second embodiment using equation (3). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding components are denoted by the same or corresponding reference numerals, and the description thereof may be omitted.

[0014] 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, the Y-axis direction, and the Z-axis direction are perpendicular to each other. The X-axis direction and the Y-axis direction represent the horizontal direction, and the Z-axis direction represents the vertical direction. When the mold clamping device 100 is 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 operation side, and the positive side of the Y-axis direction is called the anti-operation side.

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

[0016] (mold clamping device) In the description of the clamping unit 100, the moving direction of the movable platen 120 during mold closing (for example, the positive direction of the X-axis) is the front, and the moving direction of the movable platen 120 during mold opening (for example, the negative direction of the X-axis) is 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 apparatus 100 is, for example, a horizontal type, and the mold opening and closing direction is horizontal. The mold clamping apparatus 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 in the mold opening and closing direction relative to the fixed platen 110.

[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 disposed 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 advances and retreats the movable platen 120 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 disposed at a distance from the fixed platen 110, a tie bar 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 and 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 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 bar 140 connects the fixed platen 110 and the toggle support 130 at a distance L in the mold opening / closing direction. A plurality of tie bars 140 (for example, four) may be used. The plurality of tie bars 140 are arranged parallel to the mold opening / closing direction and extend according to the mold clamping force. At least one tie bar 140 may be provided with a tie bar strain detector 141 that detects strain of 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 for detecting the mold clamping force, etc.

[0025] In this embodiment, the tie bar strain detector 141 is used as the clamping force detector for detecting the clamping force, but the present invention is not limited to this. The clamping force detector is not limited to the strain gauge type, and may be a piezoelectric type, a capacitive type, a hydraulic type, an electromagnetic type, or the like, and the attachment position thereof is also not limited to the tie bar 140.

[0026] 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 stretch 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 stretchable by a pin or the like. The first link 152 is attached to the movable platen 120 by a pin or the like so as to be swingable. The second link 153 is attached to the toggle support 130 by a pin or the like so as to be swingable. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 is advanced or retreated relative to the toggle support 130, the first link 152 and the second link 153 bend and stretch, and the movable platen 120 advances or retreats relative to the toggle support 130.

[0027] The configuration of toggle mechanism 150 is not limited to the configuration shown in Figures 1 and 2. For example, although the number of joints in each link group is five in Figures 1 and 2, it may be four, and one end of third link 154 may be connected to a joint between first link 152 and second link 153.

[0028] The mold clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The mold clamping motor 160 advances and retreats the crosshead 151 relative to the toggle support 130, thereby bending and extending the first link 152 and the second link 153 and advancing and retreating the movable platen 120 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.

[0029] 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.

[0030] The mold clamping unit 100 performs a mold closing process, a pressure increase process, a mold clamping process, a pressure release process, a mold opening process, and the like under the control of the control device 700.

[0031] In the mold closing process, the mold clamping motor 160 is driven to move the crosshead 151 forward at a set moving 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 moving speed of the crosshead 151 are detected by 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.

[0032] 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 devices 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 devices can be used.

[0033] 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.

[0034] 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.

[0035] 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 in which the insert material and the molding material are integrated is obtained.

[0036] 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.

[0037] 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. After that, the ejector unit 200 ejects the molded product from the movable mold 820.

[0038] The setting conditions in the mold closing process, the pressure increase process, and the mold clamping process are set together as a series of setting conditions. For example, the moving speed and position of the crosshead 151 in the mold closing process and the pressure increase process (including the mold closing start position, the moving speed switching position, the mold closing completion position, and the mold clamping position) and the mold clamping force are set together as a series of setting conditions. The mold closing start position, the moving speed switching position, the mold closing completion position, and the mold clamping position are arranged in this order from the rear side to the front, and represent the start point and the end point of the section in which the moving speed is set. The moving speed is set for each section. There may be one or more moving speed switching positions. The moving speed switching position does not have to be set. Only one of the mold clamping position and the mold clamping force may be set.

[0039] The setting conditions in the depressurization process and mold opening process are set in the same 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 in 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 the mold closing completion position may be the same position. Also, the mold opening completion position and the mold closing start position may be the same position.

[0040] Note 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. Moreover, the clamping force may be set instead of the position of the crosshead (e.g., the clamping position) or the position of the movable platen.

[0041] Incidentally, the toggle mechanism 150 amplifies the driving force of the mold clamping motor 160 and transmits it to the movable platen 120. The amplification ratio is also called the toggle ratio. The toggle ratio changes according to 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 ratio is maximum.

[0042] When the thickness of the mold device 800 changes due to replacement of the mold device 800 or a temperature change of the mold device 800, a mold thickness adjustment is performed so that a predetermined clamping force is obtained during mold clamping. In the 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 mold touch time when the movable mold 820 touches the fixed mold 810.

[0043] The mold clamping device 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 on the toggle support 130, and a mold thickness adjustment motor 183 that rotates the screw nut 182 screwed onto the screw shaft 181.

[0044] The screw shaft 181 and the 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 multiple screw nuts 182 via a rotational driving force transmission unit 185. The multiple screw nuts 182 can be rotated synchronously. Note that by changing the transmission path of the rotational driving force transmission unit 185, it is also possible to rotate the multiple screw nuts 182 individually.

[0045] The rotational drive force transmission unit 185 is composed of, 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 the drive gear is rotatably held in the center of the toggle support 130. Note that the rotational drive force transmission unit 185 may be composed of a belt, a pulley, or the like, instead of gears.

[0046] The operation of the mold thickness adjustment mechanism 180 is controlled by a control device 700. The control device 700 drives the 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 interval 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.

[0047] The distance L is detected using a mold thickness adjustment motor encoder 184. The mold thickness adjustment motor encoder 184 detects the amount of rotation and the 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 distance L. Note that the toggle support position detector that detects the position of the toggle support 130 and the distance detector that detects the distance L are not limited to the mold thickness adjustment motor encoder 184, and general types can be used.

[0048] The mold clamping apparatus 100 may have a mold temperature regulator that regulates the temperature of the mold apparatus 800. The mold apparatus 800 has a flow path for a temperature control medium therein. The mold temperature regulator regulates the temperature of the mold apparatus 800 by regulating the temperature of the temperature control medium supplied to the flow path of the mold apparatus 800.

[0049] Although the mold clamping apparatus 100 of this embodiment is of a horizontal type in which the mold opening and closing direction is horizontal, it may be of a vertical type in which the mold opening and closing direction is vertical.

[0050] Although the mold clamping apparatus 100 of the present embodiment has a mold clamping motor 160 as a drive source, it may have a hydraulic cylinder instead of the mold clamping motor 160. Also, the mold clamping apparatus 100 may have a linear motor for opening and closing the mold, and an electromagnet for mold clamping.

[0051] (Ejector device) In describing the ejector unit 200, similar to the description of the mold clamping unit 100, the direction of movement of the movable platen 120 during mold closing (e.g., the positive direction of the X-axis) will be referred to as the forward direction, and the direction of movement of the movable platen 120 during mold opening (e.g., the negative direction of the X-axis) will be referred to as the rearward direction.

[0052] 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).

[0053] 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.

[0054] 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 the 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. A ball or roller may be interposed between the screw shaft and the screw nut.

[0055] The ejector unit 200 performs an ejection process under the control of the control unit 700. In the ejection process, the ejector rod 210 advances 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 move the ejector rod 210 backward at the set moving speed, and the ejector plate 826 backward to the original standby position.

[0056] The position and moving speed of the ejector rod 210 are detected, for example, by using 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 moving speed detector that detects the moving speed of the ejector rod 210 are not limited to the ejector motor encoder, and general types can be used.

[0057] (injection device) In the explanation of the injection device 300, unlike the explanations of the mold clamping device 100 and the ejector device 200, the axial direction of the screw 330 during filling (e.g., the negative X-axis direction among the directions in which the screw 330 can move) will be described as the front, and the axial direction of the screw 330 during metering (e.g., the positive X-axis direction among the directions in which the screw 330 can move) will be described as the rear.

[0058] The injection device 300 is installed on a slide base 301, and the slide base 301 is disposed so as to be movable forward and backward with respect to the injection device frame 920. The injection device 300 is disposed so as to be movable forward and backward with respect to the mold device 800. The injection device 300 touches the mold device 800 and fills a cavity space 801 in the mold device 800 with a molding material. The injection device 300 has, for example, a cylinder 310 for heating the molding material, a nozzle 320 provided at the front end of the cylinder 310, a screw 330 disposed in the cylinder 310 so as to be movable forward and backward and rotatable, a metering motor 340 for rotating the screw 330, an injection motor 350 for moving the screw 330 forward and backward, and a load detector 360 for detecting a load transmitted between the injection motor 350 and the screw 330.

[0059] Cylinder 310 heats the molding material supplied to the inside from supply port 311. The molding material includes, for example, resin. The molding material is formed, for example, in the shape of pellets, and is 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 heater 313 such as a band heater and a temperature detector 314 are provided on the outer periphery of cylinder 310, forward of cooler 312.

[0060] Cylinder 310 is divided into a plurality of zones in the axial direction (e.g., X-axis direction) of cylinder 310. Each of the plurality of zones is provided with heater 313 and temperature detector 314. A set temperature is set for each of the plurality of zones, and control device 700 controls heater 313 so that the detected temperature of temperature detector 314 becomes the set temperature.

[0061] The nozzle 320 is provided at the front end of the cylinder 310, and is pressed against the mold device 800. A heater 313 and a temperature detector 314 are provided on the outer periphery of the nozzle 320. The control device 700 controls the heater 313 so that the detected temperature of the nozzle 320 becomes the set temperature.

[0062] The screw 330 is disposed in 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 heat from the cylinder 310. As the liquid molding material is sent forward 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.

[0063] A check ring 331 is attached to the front of the screw 330 so as to be movable back and forth as a check valve for preventing the backflow of molding material from the front to the rear of the screw 330 when the screw 330 is pushed forward.

[0064] 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 backward relatively to the screw 330 to a blocking position (see FIG. 2) where the flow path of the molding material is blocked. This prevents the molding material accumulated in front of the screw 330 from flowing backward.

[0065] 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 relatively to the screw 330 to an open position (see FIG. 1) where the flow path of the molding material is opened. As a result, the molding material is sent forward of the screw 330.

[0066] 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.

[0067] The injection device 300 may have a drive source for moving the backflow prevention ring 331 back and forth between the open position and the closed position relative to the screw 330.

[0068] 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.

[0069] 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 the 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.

[0070] 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 a load transmission path between the injection motor 350 and the screw 330, and detects the load acting on the load detector 360.

[0071] 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.

[0072] The pressure detector for detecting the pressure of the molding material is not limited to the load detector 360, and a general detector may 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.

[0073] The injection device 300 performs a metering process, a filling process, a pressure holding process, and the like under the control of the control device 700. The filling process and the pressure holding process may be collectively referred to as the injection process.

[0074] In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set rotation speed, and the molding material is sent forward along the spiral groove of the screw 330. As a result, the molding material is gradually melted. As the liquid molding material is sent forward of the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is moved backward. The rotation speed of the screw 330 is detected, for example, by 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 rotation speed detector that detects the rotation speed of the screw 330 is not limited to the metering motor encoder 341, and a general one can be used.

[0075] In the metering process, in order to restrict abrupt retraction of the screw 330, a set back pressure may be applied to the screw 330 by driving the injection motor 350. The back pressure on the screw 330 is detected, for example, by using a load detector 360. When the screw 330 retracts to the metering completion position and a predetermined amount of molding material is accumulated in front of the screw 330, the metering process is completed.

[0076] The axial 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 in 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.

[0077] In the filling step, 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, for example, by using 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, switching from the filling step to the pressure holding step (so-called V / P switching) is performed. The position where the V / P switching is performed is also called the V / P switching position. The set moving speed of the screw 330 may be changed depending on the position of the screw 330, time, etc.

[0078] 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 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 positions do not have to be set.

[0079] An upper limit value for the pressure of the screw 330 is set for each section in which the moving speed of the screw 330 is set. The pressure of the screw 330 is detected by 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 moving speed. On the other hand, when the pressure of the screw 330 exceeds the set pressure, the screw 330 is advanced at a moving speed slower than the set moving speed so that the pressure of the screw 330 is equal to or lower than the set pressure, for the purpose of protecting the die.

[0080] After the position of the screw 330 reaches the V / P switching position in the filling process, the screw 330 may be temporarily stopped at the V / P switching position, and then the V / P switching may be performed. Immediately before the V / P switching, instead of stopping the screw 330, the screw 330 may be moved forward or backward at a slow speed. 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.

[0081] In the holding pressure step, the injection motor 350 is driven to push the screw 330 forward, and the pressure of the molding material at the front end of the screw 330 (hereinafter also referred to as "holding pressure") is maintained at a set pressure, and the molding material remaining in the cylinder 310 is pushed toward the mold device 800. The molding material that is insufficient due to cooling contraction in the mold device 800 can be replenished. The holding pressure is detected, for example, by a load detector 360. The set value of the holding pressure may be changed depending on the elapsed time from the start of the holding pressure step. The holding pressure and the holding time for which the holding pressure is held in the holding pressure step may each be set multiple times, or may be set collectively as a series of setting conditions.

[0082] 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 is started. In the cooling step, the molding material in the cavity space 801 is solidified. A measuring step may be performed during the cooling step in order to shorten the molding cycle time.

[0083] The injection device 300 of this embodiment is of an in-line screw type, but may be of a pre-plastication type or the like. A pre-plastication 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 as to be rotatable but unable to move forward or backward, or a screw is disposed so as to be rotatable and able to move forward or backward. Meanwhile, a plunger is disposed in the injection cylinder so as to be able to move forward or backward.

[0084] Furthermore, the injection device 300 of this embodiment is a horizontal type in which the axial direction of the cylinder 310 is horizontal, but may be a vertical type in which the axial direction of the cylinder 310 is vertical. A mold clamping device to be combined with the vertical injection device 300 may be either a vertical type or a horizontal type. Similarly, a mold clamping device to be combined with the horizontal injection device 300 may be either a horizontal type or a vertical type.

[0085] (Mobile device) In the description of the moving device 400, similar to the description of the injection device 300, the axial direction of the screw 330 during filling (e.g., the negative X-axis direction) is the front direction, and the axial direction of the screw 330 during metering (e.g., the positive X-axis direction) is the rear direction.

[0086] The moving device 400 moves the injection device 300 forward and backward relative to the mold device 800. In addition, the moving device 400 presses the nozzle 320 against the mold device 800 to generate a nozzle touch pressure. The moving device 400 includes a hydraulic pump 410, a motor 420 as a drive source, a hydraulic cylinder 430 as a hydraulic actuator, and the like.

[0087] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a pump that can rotate in both directions, and by switching the rotation direction of the motor 420, 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 the hydraulic fluid from one of the first port 411 and the second port 412.

[0088] The motor 420 operates the hydraulic pump 410. The motor 420 drives the hydraulic pump 410 with a rotational direction and 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.

[0089] The hydraulic cylinder 430 has a cylinder body 431, a piston 432, and a piston rod 433. The cylinder body 431 is fixed to the injection device 300. The piston 432 divides the inside of the cylinder body 431 into a front chamber 435 as a first chamber and a rear chamber 436 as a second chamber. The piston rod 433 is fixed to the fixed platen 110.

[0090] 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 die 810. The front chamber 435 functions as a pressure chamber that generates a nozzle touch pressure of the nozzle 320 by the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

[0091] On the other hand, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via the second flow path 402. The hydraulic fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second flow path 402, 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.

[0092] 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.

[0093] (Control device) The control device 700 is configured, for example, by a computer, and has a CPU (Central Processing Unit) 701, a storage medium 702 such as a memory, an input interface 703, and an output interface 704 as shown in Fig. 1 and Fig. 2. 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.

[0094] The control device 700 repeatedly 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, thereby repeatedly manufacturing a molded product. A series of operations for obtaining a molded product, for example, an operation from the start of a metering process to the start of the next metering process, is also called a "shot" or a "molding cycle." The time required for one shot is also called a "molding cycle time" or a "cycle time."

[0095] One molding cycle includes, for example, 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, 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 pressure release process coincides with the start of the mold opening process.

[0096] In addition, in order to shorten the molding cycle time, a plurality of processes may be performed simultaneously. 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. In the case where an opening / closing valve for opening and closing 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 opening / closing valve closes the flow path of the nozzle 320.

[0097] 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.

[0098] For example, after the dwelling step is completed, a pre-metering suck-back step may be performed in which the screw 330 is retracted to a preset metering start position before the metering step is started. This can reduce the pressure of the molding material accumulated in front of the screw 330 before the metering step starts, and can prevent the screw 330 from suddenly retracting at the start of the metering step.

[0099] Furthermore, after the metering step is completed, a post-metering suck-back step may be performed in which the screw 330 is moved back to a preset filling start position (also called the "injection start position") before the filling step is started. This can reduce the pressure of the molding material accumulated in front of the screw 330 before the filling step is started, and can prevent the molding material from leaking from the nozzle 320 before the filling step is started.

[0100] 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 configured, for example, by a touch panel 770 and may be integrated. The touch panel 770 as the display device 760 displays a screen under the control of the control device 700. For example, the screen of the touch panel 770 may display information such as the settings of the injection molding machine 10 and the current state of the injection molding machine 10. In addition, for example, an operation unit such as a button that accepts an input operation by a user and an input field may be displayed on the screen of the touch panel 770. The touch panel 770 as the operation device 750 detects an input operation on the screen by the user and outputs a signal corresponding to the input operation to the control device 700. Thereby, for example, the user can operate the operation unit provided on the screen while checking the information displayed on the screen to perform settings of the injection molding machine 10 (including input of a setting value). In addition, the user can operate the operation unit provided on the screen to perform an operation of the injection molding machine 10 corresponding to the operation unit. 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 be the switching of a screen displayed on the touch panel 770 serving as the display device 760, etc.

[0101] In this embodiment, the operation device 750 and the display device 760 are described as being integrated as the touch panel 770, but 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 (Y-axis negative direction) of the mold clamping unit 100 (more specifically, the fixed platen 110).

[0102] (Details of the injection unit) FIG. 3 is a diagram showing a state of the injection device according to an embodiment at the start of injection. FIG. 4 is a diagram showing a state of the injection device according to an embodiment at the completion of injection. FIG. 5 is a partially enlarged view of FIG. 4. The injection device 300 has an injection device main body 303 and a support frame 304 that supports the injection device main body 303. The injection device main body 303 includes, for example, a cylinder 310, a nozzle 320, a screw 330, a metering motor 340, an injection motor 350, and a load detector 360. The injection device main body 303 further includes a bearing 361 that rotatably supports the screw 330, a drive shaft 362 that is advanced and retreated while being rotated by the injection motor 350, and a bearing holder 370 that rotatably supports the drive shaft 362 via the bearing 361.

[0103] The support frame 304 is mounted on the slide base 301. The slide base 301 advances and retreats along two guides 302 (only one is shown in FIGS. 3 and 4). The two guides 302 are mounted on the injection device frame 920. The two guides 302 each extend in the X-axis direction. The two guides 302 are disposed at an interval in the Y-axis direction. The support frame 304 is mounted on the slide base 301 so as to be rotatable about a vertical rotation axis 304Z. The injection device main body 303 can rotate together with the support frame 304.

[0104] The support frame 304 has a front pivot plate 305 and a rear pivot plate 306. The front pivot plate 305 and the rear pivot plate 306 are slidably placed on the upper surface of the slide base 301. A pivot shaft 304Z is disposed at a predetermined position of the front pivot plate 305. The rear pivot plate 306 is disposed behind the front pivot plate 305.

[0105] The support frame 304 has a front flange 307, a rear flange 308, and a plurality of connecting rods 309. The front flange 307 is attached to the front pivot plate 305. The rear flange 308 is attached to the rear pivot plate 306. The connecting rods 309 connect the front flange 307 and the rear flange 308 with a gap therebetween.

[0106] A cylinder 310 and a metering motor 340 are attached to the front flange 307. The cylinder 310 is disposed in front of the front flange 307, and is attached to the front flange 307 via a cylindrical body 315. The metering motor 340 is disposed behind the front flange 307 and in front of the rear flange 308.

[0107] On the other hand, an injection motor 350 is attached to the rear flange 308. The injection motor 350 is disposed behind the rear flange 308, and is attached to the rear flange 308 via a load detector 360, which will be described later.

[0108] The metering motor 340 rotates the screw 330. The metering motor 340 has a stator 342 fixed to the front flange 307, a rotor 343 rotating inside the stator 342, and a bearing 349 that rotatably supports the rotor 343. The stator 342 includes a front flange 342a that holds the bearing 349, a rear flange 342b that holds the bearing 349, and a housing 342c that connects the front flange 342a and the rear flange 342b. The rotational motion of the metering motor 340 is transmitted to the bearing holder 370, and further transmitted from the bearing holder 370 to the screw 330.

[0109] The bearing holder 370 has a screw mounting portion 372 to which the screw 330 is mounted, and a metering spline shaft 371 to which the rotor 343 of the metering motor 340 is splined. The metering spline shaft 371 is disposed inside the rotor 343 of the metering motor 340. The rotor 343 is provided with a metering spline nut 344.

[0110] Meter spline nut 344 has a plurality of keyways arranged at equal intervals in the circumferential direction on its inner peripheral surface. Meanwhile, meter spline shaft 371 has a plurality of keys arranged at equal intervals in the circumferential direction on its outer peripheral surface. Meter spline shaft 371 and meter spline nut 344 are spline-coupled. Note that the number of keyways and the number of keys may be one.

[0111] The injection motor 350 advances and retreats the screw 330. The injection motor 350 has a stator 352 fixed to the rear flange 308 via a load detector 360, a rotor 353 rotating inside the stator 352, and a bearing 359 rotatably supporting the rotor 353. The rotational motion of the injection motor 350 is converted into a rotational linear motion of a drive shaft 362, and is further converted into a linear motion of a bearing holder 370. As the bearing holder 370 advances and retreats, the screw 330 advances and retreats.

[0112] The drive shaft 362 has, from the rear side to the front, an injection spline shaft 363, a screw shaft 364, and a rotation shaft 365, which are arranged in this order on a straight line.

[0113] The injection spline shaft 363 is disposed inside the rotor 353 of the injection motor 350. The rotor 353 is provided with an injection spline nut 354. The injection spline nut 354 has a plurality of keyways arranged at equal intervals in the circumferential direction on its inner peripheral surface. On the other hand, the injection spline shaft 363 has a plurality of keys arranged at equal intervals in the circumferential direction on its outer peripheral surface. The injection spline shaft 363 and the injection spline nut 354 are spline-coupled. The number of keyways and the number of keys may be one.

[0114] The screw shaft 364 is screwed into the screw nut 366. A ball or roller may be interposed between the screw shaft 364 and the screw nut 366. The screw nut 366 is fixed to the rear flange 308 via the load detector 360, and therefore does not rotate together with the screw shaft 364. Therefore, the screw shaft 364 advances and retreats while rotating. The injection spline shaft 363 and the injection spline nut 354 are splined together so that the screw shaft 364 can advance and retreat while rotating.

[0115] The rotating shaft 365 is held in a bearing holder 370 via a bearing 361. The bearing holder 370 has a cylindrical meter spline shaft 371, and the bearing 361 is fixed to the inner peripheral surface of the meter spline shaft 371. The bearing 361 has an inner ring that rotates together with the rotating shaft 365 and an outer ring that is fixed to the meter spline shaft 371. The bearing 361 prevents the transmission of a rotational driving force from the rotating shaft 365 to the bearing holder 370.

[0116] As the rotating shaft 365 advances and retreats while rotating, the bearing holder 370 advances and retreats, and the screw 330 advances and retreats. When the screw 330 advances and retreats, the metering motor 340 does not advance and retreat. This is because the metering spline nut 344 of the metering motor 340 and the metering spline shaft 371 of the bearing holder 370 are spline-coupled. Since the metering motor 340 is not included in the objects driven by the injection motor 350, the inertia of the objects driven by the injection motor 350 is small, and the screw 330 accelerates quickly when it starts to advance forward.

[0117] The structure of the injection device 300 is not limited to the structure shown in Figures 3 and 4. For example, the arrangement of the drive sources (e.g., the metering motor 340 and the injection motor 350) that drive the screw 330 is not limited to the arrangement shown in Figures 3 and 4. Specifically, in this embodiment, the rotation center line of the screw 330, the rotation center line of the metering motor 340, and the rotation center line of the injection motor 350 are arranged on the same straight line, but they do not have to be arranged on the same straight line.

[0118] 3 and 4. The structure of the transmission mechanism that transmits the driving force of the driving source to the screw 330 is not limited to the structure shown in FIG. 3 and FIG. 4. The structure of the transmission mechanism is appropriately changed depending on the arrangement of the driving source that drives the screw 330. For example, when the rotation center line of the metering motor 340 and the rotation center line of the screw 330, which are parallel to each other, are arranged to be shifted in a direction perpendicular to these rotation center lines, a timing belt may be used. Similarly, when the rotation center line of the injection motor 350 and the rotation center line of the screw 330, which are parallel to each other, are arranged to be shifted in a direction perpendicular to these rotation center lines, a timing belt may be used.

[0119] The coupling 375 connects the screw 330 and the bearing holder 370. The coupling 375 has a spline nut 376 to which the spline shaft 332 formed on the rear end of the screw 330 is spline-connected, and a flange 377 that presses the spline shaft 332 from the front. The flange 377 is fitted into a groove 333 of the screw 330. The groove 333 is formed in front of the spline shaft 332. The flange 377 is divided into two arc-shaped segments that are fitted into the groove 333 and press the spline shaft 332 from the front.

[0120] The flange 377 is fastened to the spline nut 376 by a first bolt 378. The spline nut 376 is fastened to the bearing holder 370 by a second bolt 379, and holds the load detector 360 from the front. The first bolt 378 and the second bolt 379 are tightened and loosened through a window 316 in the cylinder 315 disposed between the front flange 307 and the cooler 312.

[0121] The cylindrical body 315 includes a cylindrical portion 315a protruding forward from the front flange 307, and an inner flange portion 315b protruding inward of the cylindrical portion 315a from a front end surface of the cylindrical portion 315a. A window 316 is formed in the cylindrical portion 315a. The outer edge of the cylinder 310 is fixed to the inner edge of the inner flange portion 315b.

[0122] The bearing holder 370 has an annular groove on its outer circumferential surface, into which annular packing 381 is fitted, and an annular groove into which a slide ring 382 is fitted.

[0123] The annular packing 381 is held, for example, by the bearing holder 370, and is in slidable contact with the rotor 343 of the metering motor 340 to seal the gap between the rotor 343 and the bearing holder 370. This makes it possible to prevent the lubricant supplied to the metering spline shaft 371 from leaking to the screw 330 side.

[0124] The annular packing 381 only needs to be attached forward of the key 371a of the meter spline shaft 371, and may be attached to the meter spline shaft 371, or may be attached to the screw attachment portion 372 as shown in FIGS.

[0125] As the annular packing 381, for example, an O-ring having a circular cross-sectional shape is used, and is used by being appropriately compressed. In order to ensure sealing performance, the annular packing 381 is formed of a material softer than the slide ring 382. As a material for the annular packing 381, for example, rubber such as butyl rubber is used.

[0126] In this embodiment, the annular gasket 381 is held by the bearing holder 370, but it may also be held by the rotor 343 of the metering motor 340, be in slidable contact with the bearing holder 370, and seal the gap between the rotor 343 and the screw mounting portion 372.

[0127] The slide ring 382 is held, for example, by the screw mounting portion 372, and is in slidable contact with the rotor 343 of the metering motor 340, and aligns the center line of the rotor 343 with the center line of the screw mounting portion 372. This makes it possible to prevent the rotor 343 from galling with the screw mounting portion 372. In addition, it is possible to prevent an unbalanced load from being applied to the annular packing 381.

[0128] The slide ring 382 is formed of a material harder than the annular packing 381 in order to suppress eccentricity between the rotor 343 and the screw mounting portion 372. The material of the slide ring 382 is a crystalline resin having high self-lubrication properties. Examples of the crystalline resin include polytetrafluoroethylene (PTFE), polyamide (PA), polyester (PEs), and polyethylene (PE). The higher the degree of crystallinity, the higher the self-lubrication properties. The slide ring 382 may be formed of a resin other than the crystalline resin, for example, a phenolic resin containing cloth.

[0129] Unlike the annular packing 381, the slide ring 382 does not ensure sealing performance and therefore has a slit in a portion of the circumferential direction. The slit is formed for mounting and removing the slide ring 382, ​​and is widened when mounting and removing the slide ring 382, ​​and then returns to its original shape by the elastic restoring force of the slide ring 382.

[0130] In this embodiment, the slide ring 382 is held by the screw mounting portion 372, but it may be held by the rotor 343 of the metering motor 340, be in slidable contact with the screw mounting portion 372, and align the center line of the rotor 343 with the center line of the screw mounting portion 372. Also, the number of slide rings 382 may be multiple.

[0131] As shown in FIGS. 3 to 5, a slide ring 382 and annular packing 381 are disposed in this order from the key 371a side (rear side) of the meter spline shaft 371 toward the screw 330 side (front side). The annular packing 381 prevents the lubricant, which is supplied to the meter spline shaft 371 and passes through the slide ring 382, ​​from leaking toward the screw 330 side. By supplying the lubricant to the slide ring 382, ​​the sliding resistance of the slide ring 382 can be reduced, and leakage of the lubricant toward the screw 330 side can be suppressed. Here, the lubricant supplied to the meter spline shaft 371 passes between the slide ring 382 and the rotor 343 of the metering motor 340, between the slide ring 382 and the screw mounting portion 372, and through slits formed in the slide ring 382.

[0132] The injection molding machine 10 includes a load detector 360. The load detector 360 detects a load transmitted between the injection motor 350 and the screw 330. The load detector 360 detects a load behind the bearing 361. The load detector 360 is, for example, a washer type, and is disposed between the rear flange 308 and the injection motor 350.

[0133] The load detected by load detector 360 includes the sliding resistance of the mechanical elements, etc. The sliding resistance of the mechanical elements includes, for example, the sliding resistance between the outer ring and inner ring of bearing 361, the sliding resistance between screw shaft 364 and screw nut 366, the sliding resistance between injection spline shaft 363 and injection spline nut 354, and the sliding resistance between meter spline shaft 371 and meter spline nut 344.

[0134] FIG. 6 is a diagram showing components of a control device 700 according to an embodiment in the form of functional blocks. Each functional block shown in FIG. 6 is conceptual, and does not necessarily have to be physically configured as shown in the figure. All or a part of each functional block can be functionally or physically distributed and integrated in any unit. All or any part of the processing functions performed by each functional block are realized by a program executed by a CPU 701. Alternatively, each functional block may be realized as hardware using wired logic. As shown in FIG. 6, the control device 700 includes a correction information storage unit 601, an acquisition unit 602, a registration unit 603, a correction control unit 604, a display control unit 605, and a pressure control unit 606. The correction information storage unit 601 stores information for correcting the detection value of the pressure detected by the load detector 360 based on the speed of the screw 330, the axial phase of the screw 330, and the phase of the metering motor 340. The acquisition unit 602 acquires various information such as the detection value of the pressure detected by the load detector 360. The registration unit 603 registers information for correction in the correction information storage unit 601 based on the information acquired by the acquisition unit 602. The correction control unit 604 corrects the detection value detected by the load detector 360 based on the information stored in the correction information storage unit 601, and corrects the pressure set value used for pressure control of the screw 330. The display control unit 605 displays the corrected pressure value on the display device 760. The pressure control unit 606 performs pressure control based on the corrected pressure set value. Note that a specific description of each component will be given later.

[0135] Next, the operation of the injection molding machine 10 will be described.

[0136] In the metering process, the metering motor 340 is driven to rotate, and the screw 330 rotates. This causes the flight (thread) of the screw 330 to move, and the resin pellets (solid molding material) filled in the screw groove of the screw 330 are sent forward. The resin pellets are gradually melted by being heated by the heat from the heaters 313_1 to 313_5 via the cylinder 310 while moving forward inside the cylinder 310. Then, the resin pellets reach a completely melted state at the tip of the cylinder 310. Then, as the liquid molding material (resin) is sent forward of the screw 330 and accumulated in the front part of the cylinder 310, the screw 330 moves backward.

[0137] The metering motor encoder 341 detects the rotation of the metering motor 340, and transmits a signal indicating the detection result to the control device 700. The screw rotation speed detector that detects the rotation speed of the screw 330 is not limited to the metering motor encoder 341, and a general one can be used.

[0138] Conventionally, friction and offset load inside the injection device 300 have acted on the load detector 360. In the injection device 300, a test was conducted on the pressure detected by the load detector 360 when the screw 330 was not installed. As a result, it was found that the detected pressure value varies depending on the phase of the meter spline shaft 371, the position of the injection spline shaft 363, and the speed of the injection spline shaft 363.

[0139] Due to these factors, even if the value detected by the load detector 360 is the same, the actual pressure applied to the resin may change from moment to moment or vary from shot to shot.

[0140] FIG. 7 is a conceptual diagram showing pressure detected by the load detector 360 during metering in this embodiment. In the example shown in FIG. 7, each force applied during metering is indicated by an arrow. For example, a detection value 1701 is a detection value of pressure by the load detector 360. Meanwhile, it is desired that the load detector 360 detects a force 1702 due to resin pressure. However, friction and offset load inside the injection molding machine 10 affect the load detector 360. For this reason, the detection value 1701 is as shown in the following formula (1).

[0141] Detection value 1701 = resin pressure force 1702 - first sliding resistance 1703 - second sliding resistance 1706 + moment of metering spline shaft 371 1704 + moment of injection spline shaft 363 1705 ... (1)

[0142] The reason why the moment 1704 of the meter spline shaft 371 and the moment 1704 of the meter spline shaft 371 shown in equation (1) are included in the detected value 1701 is because the load detector 360 also detects forces in the torsional direction.

[0143] The first sliding resistance 1703 is, for example, a sliding resistance caused by the meter spline shaft 371, the annular packing 381, and the slide ring 382. The sliding resistance of the meter spline shaft 371 occurs at a spline-coupled portion between the meter spline nut 344 and the meter spline shaft 371. When the meter spline shaft 371 is eccentric, the contact area of ​​the meter spline shaft 371 with the meter spline nut 344 changes depending on the phase of the meter spline shaft 371. Therefore, the sliding resistance changes depending on the phase of the meter spline shaft 371. Incidentally, the meter spline shaft 371 is coupled to the screw 330 via the bearing holder 370. Therefore, in other words, the first sliding resistance 1703 changes depending on the circumferential position (rotation angle) of the screw 330.

[0144] The second sliding resistance 1706 is a sliding resistance caused by the injection spline shaft 363. That is, the sliding resistance of the second sliding resistance 1706 occurs at a spline-coupled portion between the meter spline nut 344, the injection spline shaft 363, and the injection spline nut 354. When the injection spline shaft 363 is eccentric, the area of ​​contact between the injection spline shaft 363 and the injection spline nut 354 changes depending on the phase of the injection spline shaft 363. Therefore, the second sliding resistance 1706 changes depending on the phase of the injection spline shaft 363. The injection spline shaft 363 is connected to the injection motor 350. The injection motor 350 is used to control the movement of the position of the screw 330 in the axial direction. Therefore, in other words, the second sliding resistance 1706 changes depending on the axial position of the screw 330 (the phase of the injection motor 350).

[0145] In this way, when generating a correction value for detecting force 1702 due to resin pressure, it is necessary to change it based on the circumferential position (rotation angle) of the screw 330 and the axial position of the screw 330. Note that, although the example shown in Fig. 7 shows the force during metering, the force during filling and pressure holding can also be calculated in a similar manner, and a description thereof will be omitted.

[0146] Fig. 8 is a diagram illustrating an example of the relationship between the detection value by the load detector 360 according to the first embodiment and the force due to the resin pressure. In the example shown in Fig. 8, the detection value by the load detector 360 during metering is 1801, and the resistance force due to mechanical friction and the like during metering is 1802. The resistance force 1802 includes moments (e.g., moment 1704 of the meter spline shaft 371 and moment 1704 of the injection spline shaft 363) in addition to the above-mentioned sliding resistances (e.g., first sliding resistance 1703 and second sliding resistance 1706).

[0147] Since the screw 330 retracts during metering, if the direction of the detection value 1801 detected by the load detector 360 (for example, the direction of the detection value 1701) is taken as the positive direction, then the resistance force 1802 due to mechanical friction or the like during metering acts in the negative direction. Then, the force 1803 due to the resin pressure during metering can be derived from the detection value 1801 - the resistance force 1802.

[0148] 8, the detection value 1804 by the load detector 360 during filling and pressure holding is taken as a resistance force 1805 due to mechanical friction and the like during filling and pressure holding. The resistance force 1805 includes a moment in addition to the sliding resistance described above.

[0149] Since the screw 330 advances during filling and holding pressure, if the direction of the detection value 1801 detected by the load detector 360 is taken as the positive direction, the resistance force 1805 due to mechanical friction during filling and holding pressure acts in the positive direction. The force 1806 due to the resin pressure during filling and holding pressure can be calculated by subtracting the resistance force 1805 from the detection value 1804.

[0150] 8, the force 1803 due to the resin pressure during metering is smaller than the force 1806 due to the resin pressure during filling and pressure holding. In other words, fluctuations in mechanical friction and the like have a large effect. The control device 700 of this embodiment realizes highly accurate detection even for the force 1803 due to the resin pressure during metering.

[0151] Specifically, a table that specifies a correction value from a combination of variables, each of which is a circumferential position of the screw 330, a position of the screw 330, and a screw speed, is stored in advance in the correction information storage unit 601. Then, the correction control unit 604 obtains the correction value from the table in real time and corrects the detection value of the pressure detected by the load detector 360. Since it is considered that there are individual differences for each injection unit 300, it is considered that the correction value is registered in the table in an inspection process before shipment or when the user starts up molding.

[0152] Returning to FIG. 6, the acquisition unit 602 acquires the detection value of the pressure detected by the load detector 360.

[0153] The registration unit 603 registers a correction value (an example of correction information) obtained by correcting the detection value of the load detector 360 based on the acquired detection value of the pressure in the correction information storage unit 601. The correction value in this embodiment is a value representing a force (resistance force) generated by a disturbance due to mechanical friction or the like. In this embodiment, the force due to the resin pressure can be derived by subtracting the correction value from the detection value.

[0154] 9 is a diagram showing detection values ​​detected by the load detector 360 when the circumferential position of the screw 330 (phase of the injection spline shaft 363) is moved while the circumferential position of the screw 330 is fixed. The example shown in Fig. 9 shows a fluctuation 901 of the detection value when the circumferential position (rotation angle) of the screw 330 is fixed at the initial position, a fluctuation 902 of the detection value when the circumferential position (rotation angle) of the screw 330 is fixed at +90°, a fluctuation 903 of the detection value when the circumferential position (rotation angle) of the screw 330 is fixed at +180°, and a fluctuation 904 of the detection value when the circumferential position (rotation angle) of the screw 330 is fixed at +270°.

[0155] According to the fluctuations in the detection values ​​901, 904, etc., it can be confirmed that the detection value of the pressure changes periodically according to the position of the screw 330. This change in the detection value corresponds to the change in the phase (rotation angle) of the injection spline shaft 363.

[0156] Similarly, the detected pressure value changes according to the circumferential position (rotation angle) of the screw 330. Furthermore, the detected pressure value changes according to the speed of the screw 330.

[0157] Therefore, in this embodiment, the detection value of the load detector 360 is corrected based on the circumferential position (rotation angle) of the screw 330, the axial position of the screw 330 (the phase of the injection spline shaft 363), and the speed of the screw 330.

[0158] In this embodiment, a method of creating a table in which correction values are stored in advance is used. In this embodiment, in order to create the correction information storage unit 601 in which correction values are stored, in the injection device 300, the pressure is detected by the load detector 360 in a state where the assembly of the screw 330 is not mounted. The assembly of the screw 330 may include, for example, a configuration including the screw 330, the cylinder body 315, the cylinder 310, and the nozzle 320. Note that the environment when detecting the pressure is not limited to the state where the assembly of the screw 330 is not mounted, and it may be a state where the molding material is not filled and the screw 330 is not in metal contact.

[0159] The registration unit 603 registers the detected value of the pressure detected by the load detector 360 as a correction value in the correction information storage unit 601.

[0160] FIG. 10 is a diagram illustrating a table of the correction information storage unit 601 registered in the registration unit 603 according to this embodiment. As shown in FIG. 10, the table of the correction information storage unit 601 of this embodiment can specify a correction value (force due to resin pressure) based on a combination of the axial position of the screw 330 (phase of the injection spline axis 363), the circumferential position of the screw 330 (rotation angle), and the speed of the screw 330. In the example shown in FIG. 10, a table is created for each speed of the screw 330, and the speeds of the screw 330 are V1 < V2 < V3 < maximum speed.

[0161] Then, the correction control unit 604 refers to the correction information storage unit 601, obtains a correction value based on the circumferential position of the screw 330, the axial position of the screw 330, and the speed of the screw, corrects the detected value output from the load detector 360 based on the correction value, and specifies the corrected detected value.

[0162] The display control unit 605 displays the detected value corrected by the correction control unit 604 as the force due to resin pressure on the display device 760.

[0163] The pressure control unit 606 controls the pressure so that the detection value corrected by the correction control unit 604 becomes a preset pressure setting value for the injection unit 300 to fill the molding material when the mold is closed, etc. This makes it possible to eliminate the influence of disturbances such as sliding resistance and moment, thereby improving the accuracy of the pressure control.

[0164] Fig. 11 is a flowchart for registering correction values ​​in the correction information storage unit 601 in the control device 700 according to this embodiment. When registering the correction values ​​shown in Fig. 11, it is assumed that the assembly of the screw 330 is not mounted.

[0165] First, the registration unit 603 of the control device 700 performs initial settings (S1101). In the initial settings, the axial position of the screw 330 (the phase of the injection spline shaft 363) and the circumferential position of the screw 330 (the rotation angle) are set to initial positions (e.g., "0"), and the speed of the screw 330 is set to an initial speed.

[0166] Next, the registration unit 603 performs stroke control of the screw 330 from the initial position (for example, "0") to the maximum value at the set speed (S1102).

[0167] The acquisition unit 602 acquires the detection value detected by the load detector 360 during stroke control (S1103).

[0168] The registration unit 603 registers the correction value corresponding to the detection value acquired by the acquisition unit 602 in the correction information storage unit 601 by associating it with the axial position of the screw 330, the speed of the screw 330, and the circumferential position when the detection value was detected (S1104).

[0169] The registration unit 603 determines whether or not the correction values ​​have been registered for all positions in the circumferential direction of the screw 330 at the current speed of the screw 330 (S1105).

[0170] When the registration unit 603 determines that correction values ​​have not been registered for all circumferential positions of the screw 330 (S1105: No), the circumferential position of the screw 330 is changed (S1106). In this embodiment, the circumferential position of the screw 330 is changed in the order of 0°, 90°, 180°, and 270°. Then, the process is performed again from S1102.

[0171] On the other hand, if the registration unit 603 determines that correction values ​​have been registered for all circumferential positions of the screw 330 (S1105: Yes), the registration unit 603 determines whether or not correction values ​​have been registered for all speeds of the screw 330 (S1107).

[0172] When the registration unit 603 determines that correction values ​​have not been registered for all the speeds of the screw 330 (S1107: No), the speed of the screw 330 is changed (S1108). Note that the speed of the screw 330 is changed based on the operation of the injection motor 350.

[0173] On the other hand, when the registration unit 603 determines that the correction values ​​have been registered for all the speeds of the screw 330 (S1108: Yes), the process ends.

[0174] By carrying out the above-described processing procedure, the registration of the correction values ​​in the correction information storage unit 601 is completed.

[0175] Next, the display control during weighing will be described with reference to Fig. 12, which is a flowchart showing the display process performed by the control device 700 according to this embodiment during weighing.

[0176] First, the acquisition unit 602 acquires a detection value of the pressure detected by the load detector 360 during stroke control (S1201). Furthermore, the acquisition unit 602 acquires the current speed of the screw 330, the circumferential position of the screw 330, and the axial position of the screw 330 based on the detection results of various sensors (e.g., the metering motor encoder 341 and the injection motor encoder 351) provided in the injection device 300 (S1202).

[0177] Next, the correction control unit 604 refers to the correction information storage unit 601 to obtain correction values ​​associated with the speed of the screw 330, the circumferential position of the screw 330, and the axial position of the screw 330 (S1203).

[0178] Then, the correction control unit 604 subtracts the correction value from the detection value to derive a corrected detection value.

[0179] The display control unit 605 displays the corrected detection value as a force due to the resin pressure on the display device 760 (S1204).

[0180] In this embodiment, by carrying out the above-described processing procedure, it is possible to detect the force due to the resin pressure during measurement while suppressing the influence of disturbances such as mechanical friction.

[0181] 12, a method for detecting the force due to resin pressure based on the detection value by the load detector 360 during weighing has been described. However, detection of the force due to resin pressure is not limited to during weighing. For example, the force due to resin pressure may be detected based on the detection value 804 by the load detector 360 during filling and pressure holding.

[0182] During filling and pressure maintenance, the pressure control unit 606 performs pressure control so that the correction value acquired by the correction control unit 604 becomes a preset pressure setting value for the injection unit 300 to fill the molding material.

[0183] In the present embodiment, an example has been described in which the detection value by the load detector 360 is corrected with reference to the correction information storage unit 601. However, in the present embodiment, the object to be corrected is not limited to the detection value, and the pressure setting for performing pressure control may be corrected.

[0184] In this case, the correction information storage unit 601 stores pressure set values ​​associated with the speed of the screw 330, the circumferential position of the screw 330, and the axial position of the screw 330. Then, the pressure control unit 606 performs pressure control so that the detection value acquired by the acquisition unit 602 becomes the pressure set value that is set in consideration of disturbances such as mechanical resistance.

[0185] Second Embodiment In the above-described embodiment, a method of specifying a correction value by referring to a table stored in the correction information storage unit 601 has been described. However, the first embodiment is not limited to a method of specifying a correction value only by using a table stored in the correction information storage unit 601. Therefore, in the second embodiment, a method of specifying a correction value by combining a mathematical model and a table will be described.

[0186] As shown in FIG. 9 and other figures, the force due to the disturbance changes periodically. For example, according to the fluctuations in the detection values ​​901, 904, the detection value of the pressure changes periodically according to the position of the screw 330. This change in the detection value corresponds to a change in the phase (rotation angle) of the injection spline shaft 363. Similarly, the change in the detection value occurs in response to a change in the phase of the meter spline shaft 371. Therefore, by mathematically modeling the periodic changes in each element, a correction value corresponding to the element of the disturbance can be identified from the mathematical model.

[0187] 13 is a diagram illustrating an example of resistance (including friction) that changes depending on the circumferential position (rotation angle) of the screw 330 or the axial position (phase of the injection spline shaft 363) of the screw 330. As described above, the resistance fluctuation 1301 changes periodically depending on the circumferential position (rotation angle) of the screw 330 or the axial position (phase of the injection spline shaft 363) of the screw 330.

[0188] Therefore, a sine function 1002 corresponding to the resistance fluctuation 1301 including friction can be derived. In this case, the following equation (2) can be derived. Note that the phase θ offsetis a phase offset corresponding to the friction fluctuation of the actual injection device 300. The variable k is a coefficient corresponding to the fluctuation range of the actual injection device 300. And the phase θ is the circumferential position (rotation angle) of the screw 330, or the phase of the injection spline shaft 363 that moves the position of the screw 330.

[0189] Element-wise correction value = k sin 2 ((θ-θ offset ) / 2)……(2)

[0190] Then, a formula capable of calculating a correction value related to the position (hereinafter also referred to as a position correction value) can be derived by combining a formula showing a correction value corresponding to the circumferential position (rotation angle) of the screw 330 and a formula showing a correction value corresponding to the phase of the injection spline shaft 363 that moves the position of the screw 330. Then, a formula model for calculating the correction value can be realized by combining a formula capable of calculating the correction value related to the position and a correction value corresponding to the speed of the screw 330 (hereinafter referred to as a speed correction value).

[0191] Specifically, the registration unit 603 registers each value (k, θ ij_offset , θ rt_offset , a table of the speed correction value Pv) is registered in the correction information storage unit 601. The variable k is a coefficient according to the actual fluctuation range of the injection unit 300. ij is the phase of the injection motor 350 (injection spline shaft 363) that moves the screw 330 in the axial direction. ij The relationship between the phase θ (angle) and the position of the screw 330 can be derived from the relationship between the rotation angle of the injection motor 350 and the movement amount of the screw 330, and therefore the explanation will be omitted. rt is the circumferential position (rotation angle) of the screw 330. ij_offset is a phase offset corresponding to the fluctuation of the actual axial position of the screw 330 (phase of the injection motor 350). rt_offset is a phase offset corresponding to the fluctuation of the actual circumferential position (rotation angle) of the screw 330. A table of the speed correction value Pv corresponding to the speed of the screw 330 will be described later.

[0192] Correction value = Pv k sin 2 ((θ ij -θ ij_offset ) / 2)·sin 2 ((θ rt -θ rt_offset ) / 2)……(3)

[0193] 14 is a diagram showing the structure of a speed correction value storage table held by the correction information storage unit 601 according to this embodiment. As shown in FIG. 14, the speed correction value Pv is stored in association with the axial speed of the screw 330.

[0194] As shown in the flowchart of FIG. 11 in the first embodiment, the speed correction value Pv and the variable k are determined by obtaining detection values ​​for each axial position of the screw 330 while varying the speed and circumferential position of the screw 330, and therefore the description thereof will be omitted. ij Period and phase θ ij_offset can be derived from the period and phase of the injection motor 350. Similarly, the phase θ rt Period and phase θ rt_offset can be derived from the period and phase of the metering motor 340. This makes it possible to derive the correction value based on equation (3).

[0195] 15 is a diagram illustrating an example of fluctuations in the correction value calculated by the correction control unit 604 using the formula (3). Cycles 1551, 1552, 1553, 1554, and 1555 in FIG.

[0196] 15, the correction value is set to a fluctuation 1501 corresponding to a fluctuation 901 in the detection value when the circumferential position (rotation angle) of the screw 330 is at the initial position. The correction value is set to a fluctuation 1502 corresponding to a fluctuation 902 in the detection value when the circumferential position (rotation angle) of the screw 330 is +90°. The correction value is set to a fluctuation 1503 corresponding to a fluctuation 903 in the detection value when the circumferential position (rotation angle) of the screw 330 is +180°. The correction value is set to a fluctuation 1504 corresponding to a fluctuation 904 in the detection value when the circumferential position (rotation angle) of the screw 330 is +270°.

[0197] In this manner, the correction control unit 604 of this embodiment calculates a correction value from equation (3) using the parameters and speed correction value memory table stored in the correction information memory unit 601, the circumferential position of the screw 330, the axial position of the screw 330, and the screw speed.

[0198] Then, the correction control unit 604 derives a corrected detection value by subtracting the calculated correction value from the detection value acquired by the acquisition unit 602. The subsequent processing is the same as in the above-described embodiment, and therefore a description thereof will be omitted.

[0199] (Third embodiment) In the above-described embodiment, an example in which a table is referred to when specifying a correction value has been described. However, the above-described embodiment is not limited to a method of referring to a table. In the third embodiment, a method of calculating a correction value using only a mathematical expression model is used.

[0200] In the second embodiment, a speed correction value memory table is used, but by applying a formula for calculating the speed correction value from the speed to the speed correction value Pv in equation (3) instead of the speed correction value Pv obtained from the speed correction value memory table, the correction value can be calculated using only the formula model.

[0201] For example, in a typical injection device, when the speed of the screw 330 is '0', the resistance value of mechanical friction, in other words the speed correction value, is the largest, and as the speed of the screw 330 increases, the resistance value (speed correction value) decreases. When the speed of the screw 330 reaches a predetermined value, the relationship between the speed and friction may be considered to transition linearly, and the speed correction value may be changed linearly with respect to the speed, or it may be treated as a constant since the fluctuation is smaller than static friction. By applying such a change in the speed correction value to the formula (3) as a formula, it becomes possible to calculate the correction value using only a mathematical model.

[0202] As in the above-described embodiment, the combination of the table and the mathematical expression model varies depending on the implementation. For example, it is possible to use a table when it is determined that the time required for the calculation is long, and to use a mathematical expression model when it is desired to reduce the memory capacity.

[0203] In the above embodiment, a method for determining the correction value when the screw 330 assembly is not mounted has been described, but the method for determining the correction value is not limited. For example, when the screw 330 is mounted, the correction value may be determined by filling the cylinder 310 with resin, raising the temperature, and then operating the screw 330 at a low speed. In this case, only the correction value based on the resistance force at the low speed can be determined. However, since the resistance value tends to decrease as the speed of the screw 330 increases, the correction value corresponding to the speed can be estimated.

[0204] (Modification) The above-described embodiment has been described as an example in which the correction control unit 604 corrects the detection value output from the load detector 360 based on a combination of the circumferential position of the screw 330, the position of the screw 330, and the screw speed. However, the above-described embodiment is not limited to a method of specifying a correction value based on a combination of the circumferential position of the screw 330, the position of the screw 330, and the screw speed.

[0205] For example, the correction control unit 604 may specify the correction value based on a combination of the circumferential position of the screw 330 and the position of the screw 330. Furthermore, the correction control unit 604 may specify a pressure set value specified based on a combination of the circumferential position of the screw 330 and the position of the screw 330, and the pressure control unit 606 may perform pressure control according to the specified pressure set value. Note that the method of specifying the correction value or the pressure set value based on a combination of the circumferential position of the screw 330 and the position of the screw 330 may use a table or a mathematical model.

[0206] As another example, for example, the correction control unit 604 may specify the correction value based on a combination of the circumferential position of the screw 330 and the speed of the screw 330. Furthermore, the correction control unit 604 may specify a pressure set value specified based on a combination of the circumferential position of the screw 330 and the speed of the screw 330, and the pressure control unit 606 may perform pressure control according to the specified pressure set value.

[0207] As another example, the correction control unit 604 may specify the correction value based on a combination of the axial position of the screw 330 and the speed of the screw 330. Furthermore, the correction control unit 604 may specify a pressure set value specified based on a combination of the axial position of the screw 330 and the speed of the screw 330, and the pressure control unit 606 may perform pressure control according to the specified pressure set value.

[0208] In this way, even if the correction value or pressure set value is determined based on a combination of two elements of the circumferential position of the screw 330, the position of the screw 330, and the screw speed, the detection value can be corrected with the determined correction value, or the pressure can be controlled with the corrected pressure set value, thereby achieving improved detection accuracy and improved pressure control accuracy.

[0209] Furthermore, the method of specifying the correction value is not limited to a method of specifying the correction value by a combination of two or more elements, and the correction value may be specified from one element. For example, the correction value and the pressure set value may be specified based on the circumferential position of the screw 330. Also, the correction value and the pressure set value may be specified based on the axial position of the screw 330. Also, the correction value and the pressure set value may be specified based on the speed of the screw 330.

[0210] In the above-described embodiment and modified example, the precision of pressure control in the injection and measurement process can be improved, and the variation in the detection value of the force due to the resin pressure between shots can be reduced. This makes it possible to improve the precision of the pressure control for filling the molding material and the detection of the force due to the resin pressure.

[0211] Although the embodiment of the injection molding machine according to the present invention has been described above, the present invention is not limited to the above embodiment. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. Naturally, these also fall within the technical scope of the present invention.

[0212] This application claims priority based on Japanese Patent Application No. 2021-061135, filed on March 31, 2021, the entire contents of which are incorporated by reference into this application. [Explanation of symbols]

[0213] 10 Injection molding machine 300 Injection unit 330 Screw 340 Metering motor 350 Injection motor 700 Control device 601 Correction information storage unit 602 Acquisition unit 603 Registration unit 604 Correction control unit 605 Display control unit 606 Pressure control unit

Claims

1. an injection device for filling the mold device with a molding material; A control device for controlling the injection device, The injection device has a cylinder that heats the molding material, a screw disposed in the cylinder, and a metering motor that rotates the screw; The control device includes: A correction control unit corrects a pressure set value used for pressure control of the screw based on a rotation angle of the metering motor, or corrects a detection value output from a pressure detector that detects the pressure acting on the screw. Injection molding machine.

2. an injection device for filling the mold device with a molding material; A control device for controlling the injection device, The injection device has a cylinder that heats the molding material, a screw disposed in the cylinder, and a metering motor that rotates the screw; The control device includes: A correction control unit corrects a pressure setting value used for pressure control of the screw based on a detection value of an encoder of the metering motor, or corrects a detection value output from a pressure detector that detects the pressure acting on the screw. Injection molding machine.

3. An injection device for filling a molding material into a mold device; A control device for controlling the injection device, the injection device includes a cylinder for heating the molding material, a screw disposed in the cylinder, a metering motor for rotating the screw, an injection motor coupled to an injection spline shaft, and a pressure detector for outputting a detection value that is a detection result of a pressure acting on the screw, The control device includes: a correction control unit that corrects a pressure set value used for pressure control of the screw in response to a change in the detection value that changes according to a phase of the injection spline shaft based on a rotation angle of the injection motor, or that corrects the detection value output from the pressure detector. Injection molding machine.

4. An injection device for filling a molding material into a mold device; A control device for controlling the injection device, the injection device includes a cylinder for heating the molding material, a screw disposed in the cylinder, a metering motor for rotating the screw, an injection motor coupled to an injection spline shaft, and a pressure detector for outputting a detection value that is a detection result of a pressure acting on the screw, The control device includes: a correction control unit that corrects a pressure set value used for pressure control of the screw, or corrects the detection value output from the pressure detector, in response to a change in the detection value that changes according to an axial position of the injection spline shaft, based on a rotation angle of the injection motor. Injection molding machine.

5. An injection device for filling a molding material into a mold device; A control device for controlling the injection device, the injection device includes a cylinder for heating the molding material, a screw disposed in the cylinder, a metering motor for rotating the screw, an injection motor coupled to an injection spline shaft, and a pressure detector for outputting a detection value that is a detection result of a pressure acting on the screw, The control device includes: a correction control unit that corrects a pressure set value used for pressure control of the screw, or corrects the detection value output from the pressure detector, in response to a change in the detection value that changes according to a phase of the injection spline shaft, based on a detection value of an encoder of the injection motor; Injection molding machine.

6. An injection device for filling a molding material into a mold device; A control device for controlling the injection device, the injection device includes a cylinder for heating the molding material, a screw disposed in the cylinder, a metering motor for rotating the screw, an injection motor coupled to an injection spline shaft, and a pressure detector for outputting a detection value that is a detection result of a pressure acting on the screw, The control device includes: a correction control unit that corrects a pressure set value used for pressure control of the screw, or corrects the detection value output from the pressure detector, in response to a change in the detection value that changes according to an axial position of the injection spline shaft, based on a detection value from an encoder of the injection motor; Injection molding machine.

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