Injection molding machine and injection device

Abstract

We provide technology to prevent unintended leakage of lubricating oil from injection molding machines. [Solution] The injection molding machine comprises a ball screw including a ball screw shaft and a ball screw nut, a bearing that rotatably supports the ball screw shaft, a first supply unit that supplies a first lubricant to the bearing, a second supply unit that supplies a second lubricant to the ball screw nut, a first holding unit that holds the bearing, a second holding unit that holds the ball screw nut and moves relative to the first holding unit along the ball screw shaft, an expandable cover provided between the first and second holding units and expands and contracts due to the relative movement of the first and second holding units, and a discharge unit that discharges the first and second lubricants from the inside to the outside of the expandable cover through a discharge port of the expandable cover.

Description

Technical Field

[0001] The present invention relates to an injection molding machine and an injection device.

Background Art

[0002] The injection molding machine described in Patent Document 1 includes an oil bath that houses a lubricating part, a supply part that supplies lubricating oil to the oil bath, and a discharge part that discharges lubricating oil from the oil bath. The oil bath is provided with a supply port and a discharge port. Lubricating oil is supplied into the oil bath from the supply port. The discharge port is provided between the injection motor and the front support. The discharge port is provided at the height of the central axis of the screw shaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] An injection molding machine may include a ball screw including a ball screw shaft and a ball screw nut, a bearing that rotatably supports the ball screw shaft, a first holding part that holds the bearing, and a second holding part that holds the ball screw nut. The injection molding machine moves the second holding part relative to the first holding part along the ball screw shaft by rotating the ball screw shaft.

[0005]

[0006] ​In Patent Document 1, the front support corresponds to the first holding part, and the rear support corresponds to the second holding part. The discharge port in Patent Document 1 is located further forward than the front support, so the first and second lubricating oils that accumulate between the front and rear supports cannot be quickly discharged. Therefore, the first and second lubricating oils accumulate in the space between the front and rear supports and may leak to unintended locations.

[0007] One embodiment of the present invention provides a technology for preventing unintended leakage of lubricating oil from an injection molding machine. [Means for solving the problem]

[0008] An injection molding machine according to one embodiment of the present invention comprises a ball screw including a ball screw shaft and a ball screw nut, a bearing that rotatably supports the ball screw shaft, a first supply unit that supplies a first lubricant to the bearing, a second supply unit that supplies a second lubricant to the ball screw nut, a first holding unit that holds the bearing, a second holding unit that holds the ball screw nut and moves relative to the first holding unit along the ball screw shaft, an expandable cover provided between the first and second holding units and expands and contracts due to the relative movement of the first and second holding units, and a discharge unit that discharges the first and second lubricants from the inside to the outside of the expandable cover through a discharge port of the expandable cover. [Effects of the Invention]

[0009] According to one embodiment of the present invention, it is possible to suppress the leakage of lubricating oil from an injection molding machine to unintended locations. [Brief explanation of the drawing]

[0010] [Figure 1] Figure 1 shows the state of an injection molding machine upon completion of mold opening according to one embodiment. [Figure 2] Figure 2 shows the state of an injection molding machine during mold clamping according to one embodiment. [Figure 3]Figure 3 shows a schematic example of an injection device. [Figure 4] Figure 4 is a cross-sectional view showing an example of a ball screw shaft and bearing. [Figure 5] Figure 5 is a perspective view showing an example of an injection device. [Figure 6] Figure 6 is a perspective view showing an example of a retractable cover. [Figure 7] Figure 7 is a perspective view showing an example of the first cover. [Figure 8] Figure 8(A) is a cross-sectional view showing the first example of a cap nut, Figure 8(B) is a cross-sectional view showing the second example of a cap nut, and Figure 8(C) is a cross-sectional view showing the third example of a cap nut. [Figure 9] Figure 9 is a perspective view showing an example of the second cover. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described below with reference to the drawings. In each drawing, identical or similar components are denoted by the same reference numerals, and their descriptions may be omitted.

[0012] (injection molding machine) Figure 1 shows the state of an injection molding machine when the mold opening is complete according to one embodiment. Figure 2 shows the state of the injection molding machine when the mold is clamped according to one embodiment. In this specification, the X-axis direction, Y-axis direction, and Z-axis direction are perpendicular to each other. The X-axis direction and Y-axis direction represent the horizontal direction, and the Z-axis direction represents the vertical direction. When the mold clamping device 100 is horizontal, the X-axis direction is the mold opening and closing direction, and the Y-axis direction is the width direction of the injection molding machine 10. The negative side in the Y-axis direction is called the operating side, and the positive side in the Y-axis direction is called the non-operating side.

[0013] As shown in FIGS. 1 to 2, the injection molding machine 10 includes a mold clamping device 100 that opens and closes the mold device 800, an ejector device 200 that ejects the molded product formed 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 with respect 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.

[0014] (Mold clamping device) In the description of the mold clamping device 100, the moving direction of the movable platen 120 at the time of mold closing (for example, the positive direction of the X axis) is defined as the front, and the moving direction of the movable platen 120 at the time of mold opening (for example, the negative direction of the X axis) is defined as the rear for explanation.

[0015] The mold clamping device 100 performs mold closing, pressure boosting, mold clamping, pressure release, and mold opening of the mold device 800. The mold device 800 includes a fixed mold 810 and a movable mold 820.

[0016] The mold clamping device 100 is, for example, a horizontal type, and the mold opening and closing direction is a horizontal direction. The mold clamping device 100 includes a fixed platen 110 to which the fixed mold 810 is attached, a movable platen 120 to which the movable mold 820 is attached, and a moving mechanism 102 that moves the movable platen 120 in the mold opening and closing direction with respect to the fixed platen 110.

[0017] The fixed platen 110 is fixed to the mold clamping device frame 910. The fixed mold 810 is attached to the opposing surface of the fixed platen 110 with respect to the movable platen 120.

[0018] The movable platen 120 is arranged to be movable in the mold opening and closing direction with respect to the mold clamping device frame 910. A guide 101 for guiding the movable platen 120 is laid on the mold clamping device frame 910. A movable mold 820 is attached to the opposing surface of the movable platen 120 facing the fixed platen 110.

[0019] The moving mechanism 102 performs mold closing, pressure boosting, mold clamping, pressure release, and mold opening of the mold device 800 by advancing and retreating the movable platen 120 with respect to the fixed platen 110. The moving mechanism 102 includes a toggle support 130 arranged at an interval 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 with respect to the toggle support 130, a clamping motor 160 that operates the toggle mechanism 150, a motion conversion mechanism 170 that converts the rotational motion of the clamping motor 160 into linear motion, and a mold thickness adjustment mechanism 180 that adjusts the interval between the fixed platen 110 and the toggle support 130.

[0020] The toggle support 130 is arranged at an interval from the fixed platen 110 and is placed on the mold clamping device frame 910 so as to be movable in the mold opening and closing direction. Incidentally, the toggle support 130 may be arranged to be movable along a guide laid on the mold clamping device frame 910. The guide of the toggle support 130 may be common with the guide 101 of the movable platen 120.

[0021] Incidentally, in the present embodiment, the fixed platen 110 is fixed with respect to the mold clamping device frame 910, and the toggle support 130 is arranged to be movable in the mold opening and closing direction with respect to the mold clamping device frame 910. However, the toggle support 130 may be fixed with respect to the mold clamping device frame 910, and the fixed platen 110 may be arranged to be movable in the mold opening and closing direction with respect to the mold clamping device frame 910.

[0022] The tie bars 140 connect the fixed platen 110 and the toggle support 130 at a distance L in the mold opening and closing direction. Multiple tie bars 140 (for example, four) may be used. Multiple tie bars 140 are arranged parallel to the mold opening and closing direction and stretch in accordance with the clamping force. At least one tie bar 140 may be provided with a tie bar strain detector 141 that detects the strain of the tie bar 140. The tie bar strain detector 141 sends a signal indicating its detection result to the control device 700. The detection result of the tie bar strain detector 141 is used for detecting the clamping force, etc.

[0023] In this embodiment, a tie bar strain detector 141 is used as a clamping force detector to detect the clamping force, but the present invention is not limited to this. The clamping force detector is not limited to strain gauge type, but may be piezoelectric, capacitive, hydraulic, electromagnetic, etc., and its mounting position is not limited to the tie bar 140.

[0024] The toggle mechanism 150 is positioned between the movable platen 120 and the toggle support 130, and moves the movable platen 120 in the mold opening and closing direction relative to the toggle support 130. The toggle mechanism 150 has a crosshead 151 that moves in the mold opening and closing direction, and a pair of link groups that bend and extend as the crosshead 151 moves. Each of the link groups has a first link 152 and a second link 153 that are bendable and extendable connected by a pin or the like. The first link 152 is pivotably attached to the movable platen 120 by a pin or the like. The second link 153 is pivotably attached to the toggle support 130 by a pin or the like. The second link 153 is attached to the crosshead 151 via a third link 154. When the crosshead 151 moves forward and backward relative to the toggle support 130, the first link 152 and the second link 153 bend and extend, and the movable platen 120 moves forward and backward relative to the toggle support 130.

[0025] Furthermore, the configuration of the toggle mechanism 150 is not limited to the configuration shown in Figures 1 and 2. For example, in Figures 1 and 2, each link group has five nodes, but it may also have four, and one end of the third link 154 may be connected to the node between the first link 152 and the second link 153.

[0026] The clamping motor 160 is attached to the toggle support 130 and operates the toggle mechanism 150. The clamping motor 160 moves the crosshead 151 forward and backward relative to the toggle support 130, thereby bending and extending the first link 152 and the second link 153, and moving the movable platen 120 forward and backward relative to the toggle support 130. The clamping motor 160 is directly connected to the motion conversion mechanism 170, but it may also be connected to the motion conversion mechanism 170 via a belt, pulley, or the like.

[0027] The motion conversion mechanism 170 converts the rotational motion of the 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.

[0028] The mold clamping device 100 performs processes such as mold closing, pressure boosting, mold clamping, depressurization, and mold opening under the control of the control device 700.

[0029] In the mold closing process, the clamping motor 160 is driven to advance the crosshead 151 to the mold closing completion position at a set movement speed, thereby advancing the movable platen 120 and bringing the movable mold 820 into contact with the fixed mold 810. The position and movement speed of the crosshead 151 are detected using, for example, a clamping motor encoder 161. The clamping motor encoder 161 detects the rotation of the clamping motor 160 and sends a signal indicating the detection result to the control device 700.

[0030] Furthermore, the crosshead position detector for detecting the position of the crosshead 151 and the crosshead speed detector for detecting the movement speed of the crosshead 151 are not limited to the clamping motor encoder 161, and general-purpose devices can be used. Similarly, the movable platen position detector for detecting the position of the movable platen 120 and the movable platen speed detector for detecting the movement speed of the movable platen 120 are not limited to the clamping motor encoder 161, and general-purpose devices can be used.

[0031] In the boosting process, the clamping motor 160 is further driven to advance the crosshead 151 from the closed position to the clamping position, thereby generating clamping force.

[0032] In the clamping process, the clamping motor 160 is driven to maintain the position of the crosshead 151 in the clamping position. In the clamping process, the clamping force generated in the pressurization process is maintained. In the clamping process, a cavity space 801 (see Figure 2) is formed between the movable mold 820 and the fixed mold 810, and the injection unit 300 fills the cavity space 801 with liquid molding material. A molded product is obtained when the filled molding material solidifies.

[0033] The number of cavity spaces 801 may be one or more. In the latter case, multiple molded products can be obtained simultaneously. An insert material may be placed in part of the cavity space 801, and the molding material may be filled in the other part of the cavity space 801. A molded product in which the insert material and the molding material are integrated is obtained.

[0034] In the depressurization process, the clamping motor 160 is driven to retract the crosshead 151 from the clamping position to the mold opening start position, thereby retracting the movable platen 120 and reducing the clamping force. The mold opening start position and the mold closing completion position may be the same position.

[0035] In the mold opening process, the clamping motor 160 is driven to retract the crosshead 151 from the mold opening start position to the mold opening completion position at a set movement speed, thereby retracting the movable platen 120 and separating the movable mold 820 from the fixed mold 810. Subsequently, the ejector device 200 ejects the molded product from the movable mold 820.

[0036] The setting conditions for the mold closing process, the pressure boosting process, and the mold clamping process are set together as a series of setting conditions. For example, the movement speed and position of the crosshead 151 (including the mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position), and the mold clamping force in the mold closing process and the pressure boosting process are set together as a series of setting conditions. The mold closing start position, movement speed switching position, mold closing completion position, and mold clamping position are arranged in this order from rear to front 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. There may be no movement speed switching positions. The mold clamping position and the mold clamping force may be set individually or individually.

[0037] The setting conditions for the depressurization process and the mold opening process are set similarly. For example, the movement speed and position of the crosshead 151 in the depressurization process and the 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 front to back and represent the start and end points of the sections 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. There may be no movement speed switching positions. 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.

[0038] Furthermore, instead of the movement speed and position of the crosshead 151, the movement speed and position of the movable platen 120 may be set. Also, instead of the position of the crosshead (e.g., the clamping position) or the position of the movable platen, the clamping force may be set.

[0039] Incidentally, the toggle mechanism 150 amplifies the driving force of the clamping motor 160 and transmits it to the movable platen 120. This amplification ratio is also called the toggle ratio. The toggle ratio changes depending on the angle θ between the first link 152 and the second link 153 (hereinafter also referred to as the "link angle θ"). The link angle θ can be determined from the position of the crosshead 151. The toggle ratio is maximized when the link angle θ is 180°.

[0040] If the thickness of the mold device 800 changes due to replacement of the mold device 800 or a change in the temperature of the mold device 800, the mold thickness is adjusted so that a predetermined clamping force is obtained during mold clamping. In mold thickness adjustment, for example, the distance L between the fixed platen 110 and the toggle support 130 is adjusted so that the link angle θ of the toggle mechanism 150 becomes a predetermined angle at the time of mold touch when the movable mold 820 touches the fixed mold 810.

[0041] 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 timing of the mold thickness adjustment is, for example, between the end of one molding cycle and the start of the next molding cycle. The mold thickness adjustment mechanism 180 includes, for example, a screw shaft 181 formed at the rear end of the tie bar 140, a screw nut 182 that is rotatably and immovably held by the toggle support 130, and a mold thickness adjustment motor 183 that rotates the screw nut 182 that is screwed onto the screw shaft 181.

[0042] A screw shaft 181 and 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 multiple screw nuts 182 via a rotational driving force transmission unit 185. Multiple screw nuts 182 can be rotated synchronously. It is also possible to rotate multiple screw nuts 182 individually by changing the transmission path of the rotational driving force transmission unit 185.

[0043] The rotational drive force transmission unit 185 is composed of, for example, gears. In this case, driven gears are formed on the outer circumference 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 or pulley instead of gears.

[0044] The operation of the mold thickness adjustment mechanism 180 is controlled by the control device 700. The control device 700 drives the mold thickness adjustment motor 183 to rotate the screw nut 182. As a result, the position of the toggle support 130 relative to the tie bar 140 is adjusted, and the distance L between the fixed platen 110 and the toggle support 130 is adjusted. Multiple mold thickness adjustment mechanisms may be used in combination.

[0045] The interval L is detected using the mold thickness adjustment motor encoder 184. The mold thickness adjustment motor encoder 184 detects the amount and direction of rotation of the mold thickness adjustment motor 183 and sends a signal indicating the detection result to the control device 700. The detection result of the mold thickness adjustment motor encoder 184 is used to monitor and control the position and interval L of the toggle support 130. Note that the toggle support position detector for detecting the position of the toggle support 130 and the interval detector for detecting the interval L are not limited to the mold thickness adjustment motor encoder 184, but general-purpose devices can be used.

[0046] The clamping device 100 may have a mold temperature controller that adjusts the temperature of the mold device 800. The mold device 800 has a flow path for a temperature-controlled medium inside it. The mold temperature controller adjusts the temperature of the mold device 800 by adjusting the temperature of the temperature-controlled medium supplied to the flow path of the mold device 800.

[0047] In this embodiment, the mold clamping device 100 is a horizontal type in which the mold opening and closing direction is horizontal, but it may also be a vertical type in which the mold opening and closing direction is vertical.

[0048] In this embodiment, the clamping device 100 has a clamping motor 160 as a drive unit, but a hydraulic cylinder may be used instead of the clamping motor 160. Furthermore, the clamping device 100 may have a linear motor for opening and closing the mold, and an electromagnet for clamping the mold.

[0049] (Ejector device) In describing the ejector device 200, similar to the description of the clamping device 100, the direction of movement of the movable platen 120 when the mold is closed (for example, the positive X-axis direction) is described as forward, and the direction of movement of the movable platen 120 when the mold is open (for example, the negative X-axis direction) is described as backward.

[0050] The ejector device 200 is attached to the movable platen 120 and moves back and forth together with the movable platen 120. The ejector device 200 includes an ejector rod 210 that ejects the molded product from the mold device 800 and a drive mechanism 220 that moves the ejector rod 210 in the direction of movement of the movable platen 120 (in the X-axis direction).

[0051] The ejector rod 210 is positioned to move back and forth within a through-hole in the movable platen 120. The front end of the ejector rod 210 contacts the 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.

[0052] 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.

[0053] The ejector device 200 performs the ejection process under the control of the control device 700. In the ejection process, the ejector rod 210 is advanced from the standby position to the ejection position at a set travel speed, thereby advancing the ejector plate 826 and ejecting the molded product. Subsequently, the ejector motor is driven to retract the ejector rod 210 at a set travel speed, retracting the ejector plate 826 back to its original standby position.

[0054] The position and speed of the ejector rod 210 are detected, for example, 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, which detects the position of the ejector rod 210, and the ejector rod speed detector, which detects the speed of the ejector rod 210, are not limited to ejector motor encoders, but general-purpose devices can be used.

[0055] (injection device) In the description of the injection device 300, unlike the descriptions of the clamping device 100 and the ejector device 200, the direction of movement of the screw 330 during filling (for example, the negative X-axis direction) is described as forward, and the direction of movement of the screw 330 during metering (for example, the positive X-axis direction) is described as backward.

[0056] The injection device 300 is mounted on a slide base 301, which is positioned to move back and forth relative to the injection device frame 920. The injection device 300 is positioned to move back and forth relative to the mold device 800. The injection device 300 touches the mold device 800 and fills the cavity space 801 within the mold device 800 with molding material. The injection device 300 includes, 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 positioned within the cylinder 310 to move back and forth and to rotate, a metering motor 340 for rotating the screw 330, an injection motor 350 for moving the screw 330 back and forth, and a load detector 360 for detecting the load transmitted between the injection motor 350 and the screw 330.

[0057] Cylinder 310 heats the molding material supplied to its interior from the supply port 311. The molding material includes, for example, resin. The molding material is formed, for example, into pellets and supplied to the supply port 311 in a solid state. The 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 circumference of the rear of cylinder 310. In front of the cooler 312, a first heater 313, such as a band heater, and a first temperature detector 314 are provided on the outer circumference of cylinder 310.

[0058] The cylinder 310 is divided into multiple zones along its axial direction (for example, the X-axis direction). A first heater 313 and a first temperature detector 314 are provided in each of the multiple zones. A set temperature is set for each of the multiple zones, and the control device 700 controls the first heater 313 so that the temperature detected by the first temperature detector 314 becomes the set temperature.

[0059] The nozzle 320 is located at the front end of the cylinder 310 and is pressed against the mold device 800. A second heater 323 and a second temperature detector 324 are provided on the outer circumference of the nozzle 320. The control device 700 controls the second heater 323 so that the detected temperature of the nozzle 320 reaches a set temperature.

[0060] The screw 330 is rotatably and reciprocally positioned within the cylinder 310. When the screw 330 is rotated, the molding material is fed forward along the helical groove of the screw 330. As the molding material is fed forward, it is gradually melted by the heat from the cylinder 310. As the liquid molding material is fed forward to the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is retracted. Then, when the screw 330 is advanced, the liquid molding material accumulated in front of the screw 330 is injected from the nozzle 320 and filled into the mold device 800.

[0061] A backflow prevention ring 331 is mounted on the front of the screw 330 so as to be able to move back and forth, acting as a backflow prevention valve to prevent backflow of the molding material from the front to the rear of the screw 330 when the screw 330 is pushed forward.

[0062] When the screw 330 is advanced, the backflow prevention ring 331 is pushed backward by the pressure of the molding material in front of the screw 330, and retracts relative to the screw 330 to a closed position (see Figure 2) that blocks the flow path of the molding material. This prevents the molding material accumulated in front of the screw 330 from flowing backward.

[0063] 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 being sent forward along the helical groove of the screw 330, and moves relative to the screw 330 to an open position (see Figure 1) that opens the flow path of the molding material. As a result, the molding material is sent forward of the screw 330.

[0064] 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.

[0065] Furthermore, the injection device 300 may have a drive source that moves the backflow prevention ring 331 back and forth between an open position and a closed position relative to the screw 330.

[0066] The metering motor 340 rotates the screw 330. The drive source for rotating the screw 330 is not limited to the metering motor 340; for example, a hydraulic pump or the like may also be used.

[0067] The injection motor 350 moves the screw 330 forward and backward. Between the injection motor 350 and the screw 330, there is a motion conversion mechanism that converts the rotational motion of the injection motor 350 into the linear motion of the screw 330. The motion conversion mechanism has, for example, a screw shaft and a screw nut that screws onto the screw shaft. Balls or rollers may be provided between the screw shaft and the screw nut. The drive source for moving the screw 330 forward and backward is not limited to the injection motor 350, but may also be, for example, a hydraulic cylinder.

[0068] 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 installed in the load transmission path between the injection motor 350 and the screw 330 and detects the load acting on the load detector 360.

[0069] 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 for controlling and monitoring the pressure the screw 330 receives from the molding material, the back pressure on the screw 330, and the pressure acting from the screw 330 on the molding material.

[0070] Furthermore, the pressure detector used to detect the pressure of the molding material is not limited to the load detector 360, but a general-purpose one can be used. For example, a nozzle pressure sensor or an in-mold pressure sensor may be used. The nozzle pressure sensor is installed in the nozzle 320. The in-mold pressure sensor is installed inside the mold device 800.

[0071] The injection device 300 performs processes such as metering, filling, and holding pressure under the control of the control device 700. The filling and holding pressure processes may be collectively referred to as the injection process.

[0072] In the metering process, the metering motor 340 is driven to rotate the screw 330 at a set rotational speed, and the molding material is fed forward along the helical groove of the screw 330. As this occurs, the molding material is gradually melted. As the liquid molding material is fed forward by the screw 330 and accumulates at the front of the cylinder 310, the screw 330 is retracted. The rotational speed of the screw 330 is detected, for example, using a metering motor encoder 341. The metering motor encoder 341 detects the rotation of the metering motor 340 and sends a signal indicating the detection result to the control device 700. Note that the screw rotational speed detector for detecting the rotational speed of the screw 330 is not limited to the metering motor encoder 341, and a general-purpose one can be used.

[0073] In the weighing process, the injection motor 350 may be driven to apply a set back pressure to the screw 330 in order to limit the rapid retraction of the screw 330. The back pressure on the screw 330 is detected, for example, using a load detector 360. The weighing process is completed when the screw 330 has retracted to the weighing completion position and a predetermined amount of molding material has accumulated in front of the screw 330.

[0074] The position and rotational speed of the screw 330 in the metering process are set together as a series of setting conditions. For example, the metering start position, rotational speed switching position, and metering completion position are set. These positions are arranged in this order from front to back and represent the start and end points of the sections 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 positions may not be set. In addition, back pressure is set for each section.

[0075] In the filling process, the injection motor 350 is driven to advance the screw 330 at a set speed, filling the cavity space 801 in the mold device 800 with the liquid molding material accumulated in front of the screw 330. The position and speed of the screw 330 are detected, for example, using an injection motor encoder 351. The injection motor encoder 351 detects the rotation of the injection motor 350 and sends a signal indicating the detection result to the control device 700. When the position of the screw 330 reaches the set position, a switchover from the filling process to the holding pressure process (so-called V / P switching) occurs. The position at which the V / P switching occurs is also called the V / P switching position. The set speed of the screw 330 may be changed depending on the position and time of the screw 330.

[0076] The position and movement speed of the screw 330 during the filling process are set together as a series of setting conditions. For example, the filling start position (also called the "injection start position"), the movement speed switching position, and the V / P switching position are set. These positions are arranged in this order from rear to front and represent the start and end points of the sections 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 positions may not be set at all.

[0077] For each section in which the movement speed of the screw 330 is set, an upper limit is set for the pressure of the screw 330. The pressure of the screw 330 is detected by the load sensor 360. If the pressure of the screw 330 is below the set pressure, the screw 330 moves forward at the set movement speed. On the other hand, if the pressure of the screw 330 exceeds the set pressure, for the purpose of protecting the mold, the screw 330 moves forward at a slower movement speed than the set movement speed so that the pressure of the screw 330 becomes below the set pressure.

[0078] Furthermore, during the filling process, after the screw 330 reaches the V / P switching position, 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. In addition, 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, but general-purpose ones can be used.

[0079] In the holding pressure process, the injection motor 350 is driven to push the screw 330 forward, maintaining the pressure of the molding material at the front end of the screw 330 (hereinafter also referred to as "holding pressure") at a set pressure, and pushing the molding material remaining in the cylinder 310 toward the mold device 800. This allows for the replenishment of molding material lost due to cooling shrinkage within the mold device 800. The holding pressure is detected, for example, using a load detector 360. The set value of the holding pressure may be changed according to the elapsed time from the start of the holding pressure process. Multiple holding pressures and holding times for maintaining the holding pressure in the holding pressure process may be set, and may be set together as a series of setting conditions.

[0080] During the holding pressure process, the molding material in the cavity space 801 within the mold device 800 is gradually cooled, and upon completion of the holding pressure process, the entrance to the cavity space 801 is sealed with solidified molding material. This state is called a gate seal, and prevents backflow of molding material from the cavity space 801. After the holding pressure process, the cooling process begins. During the cooling process, the molding material in the cavity space 801 is solidified. To shorten the molding cycle time, a metering process may be performed during the cooling process.

[0081] In this embodiment, the injection device 300 is an in-line screw type, but a pre-plasticization type or the like may also be used. In a pre-plasticization injection device, the molding material molten in a plasticizing cylinder is supplied to the injection cylinder, and the molding material is injected from the injection cylinder into the mold device. In the plasticizing cylinder, a screw is arranged to be rotatable but unable to move back and forth, or a screw is arranged to be rotatable and able to move back and forth. On the other hand, a plunger is arranged to be able to move back and forth in the injection cylinder.

[0082] Furthermore, although the injection device 300 in this embodiment is a horizontal type with the axial direction of the cylinder 310 being horizontal, it may also be a vertical type with the axial direction of the cylinder 310 being vertical. The clamping device combined with the vertical injection device 300 may be vertical or horizontal. Similarly, the clamping device combined with the horizontal injection device 300 may be horizontal or vertical.

[0083] (Mobile device) In describing the moving device 400, similar to the description of the injection device 300, the direction of movement of the screw 330 during filling (for example, the negative X-axis direction) is described as forward, and the direction of movement of the screw 330 during metering (for example, the positive X-axis direction) is described as backward.

[0084] The moving device 400 moves the injection device 300 forward and backward relative to the mold device 800. The moving device 400 also presses the nozzle 320 against the mold device 800, generating 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.

[0085] The hydraulic pump 410 has a first port 411 and a second port 412. The hydraulic pump 410 is a bidirectional pump, and by switching the rotation direction of the motor 420, it can draw in working fluid (e.g., oil) from either the first port 411 or the second port 412 and discharge it from the other to generate hydraulic pressure. The hydraulic pump 410 can also draw working fluid from a tank and discharge it from either the first port 411 or the second port 412.

[0086] Motor 420 operates the hydraulic pump 410. Motor 420 drives the hydraulic pump 410 with a rotational direction and rotational torque corresponding to the control signal from the control device 700. Motor 420 may be an electric motor or an electric servo motor.

[0087] The hydraulic cylinder 430 comprises 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.

[0088] The front chamber 435 of the hydraulic cylinder 430 is connected to the first port 411 of the hydraulic pump 410 via a first passage 401. The hydraulic fluid discharged from the first port 411 is supplied to the front chamber 435 via the first passage 401, pushing the injection device 300 forward. As the injection device 300 moves forward, the nozzle 320 is pressed against the fixed mold 810. The front chamber 435 functions as a pressure chamber that generates nozzle touch pressure on the nozzle 320 by the pressure of the hydraulic fluid supplied from the hydraulic pump 410.

[0089] Meanwhile, the rear chamber 436 of the hydraulic cylinder 430 is connected to the second port 412 of the hydraulic pump 410 via the second passage 402. The working fluid discharged from the second port 412 is supplied to the rear chamber 436 of the hydraulic cylinder 430 via the second passage 402, pushing the injection device 300 backward. As the injection device 300 is retracted, the nozzle 320 is separated from the fixed mold 810.

[0090] In this embodiment, the moving device 400 includes a hydraulic cylinder 430, but the present invention is not limited thereto. 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.

[0091] (Control device) The control device 700 is, for example, a computer and, as shown in Figures 1 and 2, has a CPU (Central Processing Unit) 701, a storage medium 702 such as memory, an input interface 703, and an output interface 704. The control device 700 performs various controls by having the CPU 701 execute a program stored in the storage medium 702. The control device 700 also receives signals from the outside through the input interface 703 and transmits signals to the outside through the output interface 704.

[0092] The control device 700 includes electronic circuits such as a CPU, FPGA (Field Programmable Gate Array), or ASIC (Application Specific Integrated Circuit), and performs various control operations described in this specification by executing instruction codes stored in memory or by designing the circuit for special applications.

[0093] The control device 700 repeatedly manufactures molded products by repeatedly performing processes such as metering, mold closing, pressure increasing, mold clamping, filling, holding pressure, cooling, depressurization, mold opening, and ejection. A series of operations to obtain a molded product, such as the operations from the start of one metering process to the start of the next metering process, is also called a "shot" or "molding cycle." The time required for one shot is also called the "molding cycle time" or "cycle time."

[0094] A single molding cycle includes, for example, a weighing process, a mold closing process, a pressurizing process, a clamping process, a filling process, a holding pressure process, a cooling process, a depressurizing process, a mold opening process, and an ejection process, in this order. The order here refers to the order in which each process begins. The filling, holding pressure, and cooling processes take place during the clamping process. The start of the clamping process may coincide with the start of the filling process. The completion of the depressurizing process coincides with the start of the mold opening process.

[0095] Furthermore, multiple processes may be performed simultaneously in order to shorten the molding cycle time. For example, the metering process may be performed during the cooling process of the previous molding cycle, or during the mold clamping process. In this case, the mold closing process may be performed at the beginning of the molding cycle. The filling process may also be started during the mold closing process. The ejection process may also be started during the mold opening process. If an on-off valve is provided to open and close the flow path of the nozzle 320, 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, if the on-off valve closes the flow path of the nozzle 320, the molding material will not leak from the nozzle 320.

[0096] Furthermore, a single molding cycle may include steps other than the weighing step, mold closing step, pressurization step, mold clamping step, filling step, holding pressure step, cooling step, depressurization step, mold opening step, and ejection step.

[0097] For example, after the holding pressure process is completed and before the metering process begins, a pre-metering suck-back process may be performed in which the screw 330 is retracted to a preset metering start position. This reduces the pressure of the molding material accumulated in front of the screw 330 before the metering process begins and prevents the screw 330 from retracting too quickly at the start of the metering process.

[0098] Furthermore, after the metering process is completed and before the filling process begins, a post-metering suck-back process may be performed in which the screw 330 is retracted to a preset filling start position (also called the "injection start position"). This reduces the pressure of the molding material accumulated in front of the screw 330 before the filling process begins and prevents leakage of the molding material from the nozzle 320 before the filling process begins.

[0099] The control device 700 is connected to an operating device 750 that accepts user input operations and a display device 760 that displays a screen. The operating device 750 and the display device 760 may be integrated, for example, by a touch panel 770. The touch panel 770, as the display device 760, displays a screen under the control of the control device 700. The screen of the touch panel 770 may display information such as the settings of the injection molding machine 10 and the current status of the injection molding machine 10. The screen of the touch panel 770 may also display operation parts such as buttons and input fields that accept user input operations. The touch panel 770, as the operating device 750, detects user input operations on the screen and outputs a signal corresponding to the input operation to the control device 700. This allows, for example, the user to operate the operation parts provided on the screen while confirming the information displayed on the screen to set the injection molding machine 10 (including inputting setting values). Furthermore, by operating the operation parts provided on the screen, the user can make the injection molding machine 10 operate in accordance with the operation part. The operation of the injection molding machine 10 may also include the operation (including stopping) of, for example, the clamping device 100, the ejector device 200, the injection device 300, the moving device 400, etc. Furthermore, the operation of the injection molding machine 10 may also include switching the screens displayed on the touch panel 770, which serves as the display device 760.

[0100] Although the operating device 750 and display device 760 of this embodiment have been described as being integrated as a touch panel 770, they may be provided independently. Furthermore, multiple operating devices 750 may be provided. The operating device 750 and display device 760 are positioned on the operating side (negative Y-axis direction) of the clamping device 100 (more specifically, the fixed platen 110).

[0101] (Details of the injection device) Next, the details of the injection device 300 will be described with reference to Figures 3 and 4. The injection device 300 comprises a ball screw 380, bearings 383 and 384 (see Figure 4), a first retaining part 371, and a second retaining part 372. The ball screw 380 includes a ball screw shaft 381 and a ball screw nut 382. The bearings 383 and 384 rotatably support the ball screw shaft 381. The number of bearings is not particularly limited. The first retaining part 371 holds the bearings 383 and 384. The second retaining part 372 holds the ball screw nut 382.

[0102] The injection device 300 rotates the ball screw shaft 381, causing the ball screw nut 382 to move back and forth along the ball screw shaft 381. As a result, the second retaining part 372 moves relative to the first retaining part 371. The first retaining part 371 is fixed to the slide base 301. Meanwhile, the second retaining part 372 is located behind the first retaining part 371 and moves back and forth along the guide 302 laid on the slide base 301.

[0103] Note that the slide base 301 is not required. In this case, the first retaining part 371 and the second retaining part 372 may be configured to move back and forth individually along guides laid on the injection device frame 920 (see Figure 1).

[0104] The second holding part 372 holds a bearing (not shown). This bearing rotatably supports the rotating shaft 335. The second holding part 372 also holds the metering motor 340. The metering motor 340 rotates the rotating shaft 335 via a transmission part 345. The rotating shaft 335 is connected to a screw 330 (see Figure 1). As the metering motor 340 rotates the rotating shaft 335, the screw 330 rotates inside the cylinder 310.

[0105] The first retaining part 371 holds the cylinder 310 and the injection motor 350. The cylinder 310 and the injection motor 350 are each provided, for example, in front of the first retaining part 371. The injection motor 350 rotates the ball screw shaft 381, causing the ball screw nut 382 to move back and forth along the ball screw shaft 381. As a result, the second retaining part 372 moves back and forth relative to the first retaining part 371. The rotating shaft 335 moves back and forth together with the second retaining part 372, causing the screw 330 to move back and forth inside the cylinder 310.

[0106] Although not shown in Figures 3 and 4, the injection motor 350 and ball screw 380 are provided in pairs, flanking the cylinder 310 and screw 330, respectively. This allows the screw 330 to be pushed straight.

[0107] As shown in Figure 4, the injection device 300 includes a first supply unit 391 and a second supply unit 392. The first supply unit 391 supplies first lubricating oil to bearings 383 and 384. The second supply unit 392 supplies second lubricating oil to ball screw nut 382. The first lubricating oil supplied to bearings 383 and 384 and the second lubricating oil supplied to ball screw nut 382 collect in the space between the first retaining unit 371 and the second retaining unit 372, respectively. It is preferable that the first lubricating oil and the second lubricating oil are of the same type.

[0108] The injection device 300 is equipped with an expandable cover 500. The expandable cover 500 is provided between the first holding part 371 and the second holding part 372 and expands and contracts with the relative movement of the first holding part 371 and the second holding part 372. The expandable cover 500 surrounds the ball screw shaft 381 and suppresses the radial scattering of the first lubricant and the second lubricant due to the rotation of the ball screw shaft 381. Similar to the ball screw 380, a pair of expandable covers 500 are provided, sandwiching the cylinder 310 and the screw 330. The expandable cover 500 has an outlet 501 between the first holding part 371 and the second holding part 372.

[0109] The injection device 300 is equipped with a discharge section 590. The discharge section 590 discharges the first lubricating oil and the second lubricating oil from the inside to the outside of the retractable cover 500 through the discharge port 501 of the retractable cover 500. The discharge section 590 has a tank 591 that contains the first lubricating oil and the second lubricating oil. The discharge section 590 allows for the rapid discharge of the first lubricating oil and the second lubricating oil accumulated in the retractable cover 500, and prevents leakage of the first lubricating oil and the second lubricating oil to unintended locations.

[0110] The discharge port 501 of the expandable cover 500 is preferably located below the rotational centerline of the ball screw shaft 381. By positioning the discharge port 501 downwards, the first and second lubricating oils can be quickly discharged. The position of the discharge port 501 is more preferably below the entire ball screw shaft 381, even more preferably below the balls constituting the bearings 383 and 384, and particularly preferably at the lower end of the expandable cover 500.

[0111] The expandable cover 500 includes, for example, a first cover 510 and a second cover 520. The first cover 510 is provided on the first holding portion 371, and the second cover 520 is provided on the second holding portion 372. According to this embodiment, as described above, the first and second lubricating oils that accumulate in the expandable cover 500 can be quickly discharged, and leakage of the first and second lubricating oils to unintended locations can be suppressed. Therefore, the structure of the first cover 510 and the second cover 520 can be simplified, and it is not necessary to make surface contact between one outer circumferential surface and the other inner circumferential surface, as in Patent Document 1.

[0112] The first cover 510 has a first cylinder 511 and a first frame 519. The first cylinder 511 protrudes from the first retaining portion 371 toward the second retaining portion 372. The first frame 519 is provided at the tip of the first cylinder 511 and protrudes from the inner circumferential surface of the first cylinder 511. The first cylinder 511 and the first frame 519 are integrally molded and bent at their boundary line. The first frame 519 may be molded separately from the first cylinder 511 and integrated with the first cylinder 511 by welding or other means.

[0113] The second cover 520 has a second cylinder 521. The second cylinder 521 protrudes from the second retaining portion 372 toward the first retaining portion 371. The first frame 519 surrounds the second cylinder 521. As the second retaining portion 372 moves relative to the first retaining portion 371, a portion of the second cylinder 521 moves in and out of the first cylinder 511.

[0114] The injection device 300 includes a third cover 530 separate from the retractable cover 500. The third cover 530 is located on the opposite side of the second retaining part 372 with respect to the first retaining part 371, that is, in front of the first retaining part 371. The third cover 530 surrounds the ball screw shaft 381 between the first retaining part 371 and the injection motor 350. An air breather 379 is provided in the third cover 530. The air breather 379 inhales and exhales air in accordance with the change in volume of the retractable cover 500. A first supply unit 391 is provided in the third cover 530.

[0115] Furthermore, the injection device 300 is equipped with a fourth cover 540 in addition to the telescopic cover 500. The fourth cover 540 is located on the opposite side of the second retaining portion 372 from the first retaining portion 371, that is, behind the second retaining portion 372. The fourth cover 540 surrounds the ball screw shaft 381 behind the second retaining portion 372. The fourth cover 540 has a fourth cylinder 541 and a lid 542. The fourth cylinder 541 protrudes rearward from the second retaining portion 372. The lid 542 closes the fourth cylinder 541 from the rear. An air breather 379 is provided in the fourth cover 540.

[0116] In addition to Figures 3 and 4, the first cover 510 will be described again with reference to Figures 5 and 7. As shown in Figures 5 and 6, the first cover 510 has a first cylinder 511. The first cylinder 511 protrudes from the first holding portion 371 toward the second holding portion 372. The first cylinder 511 has a first split cylinder 511A and a second split cylinder 511B provided below the first split cylinder 511A. By assembling the first split cylinder 511A and the second split cylinder 511B into a cylindrical shape, the ball screw shaft 381 can be surrounded.

[0117] The first split cylinder 511A and the second split cylinder 511B are each constructed, for example, by bending sheet metal. The first split cylinder 511A and the second split cylinder 511B are assembled, for example, into a rectangular tube shape. The first frame 519 is also divided, similar to the first cylinder 511. The first cylinder 511 and the first frame 519 may be divided along the same plane.

[0118] The first cover 510 has an inclined plate 518, as shown in Figures 4 and 7. The inclined plate 518 is located inside the first cylinder 511 and above the ball screw shaft 381. As shown in Figure 4, the inclined plate 518 is inclined downward as it approaches the first retaining portion 371 along the ball screw shaft 381. For example, the inclined plate 518 is inclined downward as it moves in the negative direction of the X axis. The inclined plate 518 may be a flat plate.

[0119] The first and second lubricants are scattered radially from the ball screw shaft 381. After adhering to the inclined plate 518, the first and second lubricants flow down along the inclined plate 518. This reduces the amount of first and second lubricants that flow down the inner surface of the first splitting cylinder 511A in the circumferential direction, and reduces the amount of first and second lubricants that leak from the dividing surface of the first splitting cylinder 511A and the second splitting cylinder 511B.

[0120] The first cover 510 has a first flange 512, as shown in Figures 5 and 6. The first flange 512 is provided at the base end of the first cylinder 511 and is attached to the first retaining part 371 with bolts or the like. The first cylinder 511 and the first flange 512 may be divided in the same plane. The first flange 512 has a first split flange 512A and a second split flange 512B provided below the first split flange 512A. The first split flange 512A and the second split flange 512B can be assembled in a ring shape to surround the ball screw shaft 381.

[0121] The first split flange 512A is provided at the base end of the first split cylinder 511A. The first split flange 512A is molded separately from the first split cylinder 511A and integrated with the first split cylinder 511A by welding or the like. The second split flange 512B is provided at the base end of the second split cylinder 511B. The second split flange 512B is molded separately from the second split cylinder 511B and integrated with the second split cylinder 511B by welding or the like. The dividing surfaces of the first split flange 512A and the second split flange 512B may be on the same plane as the dividing surfaces of the first split cylinder 511A and the second split cylinder 511B.

[0122] The first cover 510 has an inner cover 513, as shown in Figures 4 and 7. The inner cover 513 is provided inside the first flange 512 and seals the dividing surface of the first split flange 512A and the second split flange 512B. The first and second lubricants are scattered radially from the ball screw shaft 381. The inner cover 513 can reduce the amount of the first and second lubricants that leak out from the dividing surface of the first split flange 512A and the second split flange 512B.

[0123] As shown in Figure 7, the inner cover 513 covers the inner circumferential surface of the first split flange 512A over its entire circumferential direction. The inner cover 513 does not cover the inner circumferential surface of the second split flange 512B over its entire circumferential direction. For example, the inner cover 513 has a C-shape when viewed from the direction along the ball screw shaft 381 and opens downwards. The inner cover 513 is suspended, for example, from the ceiling of the first split cylinder 511A.

[0124] Furthermore, the inner cover 513 may cover the inner circumferential surface of the second split flange 512B over its entire circumferential direction. In other words, the inner cover 513 may have an O-shape when viewed from the direction along the ball screw shaft 381.

[0125] As described above, the inner cover 513 covers the inner circumferential surface of the first split flange 512A over the entire circumferential direction of the first split flange 512A. Therefore, the amount of first and second lubricants flowing down the inner circumferential surface of the first split flange 512A along the circumferential direction can be reduced, and the amount of first and second lubricants leaking from the dividing surface of the first split flange 512A and the second split flange 512B can be reduced.

[0126] As shown in Figure 4, the inner cover 513 covers at least a portion of the gap between the first flange 512 and the first retaining portion 371. Preferably, the inner cover 513 covers at least the entire gap between the first split flange 512A and the first retaining portion 371. This reduces the amount of first and second lubricating oil leaking from the gap between the first flange 512 and the first retaining portion 371.

[0127] As shown in Figures 5 and 6, the injection device 300 includes a first seal 550 and a recovery tank 560. The first seal 550 is provided between the first flange 512 and the first retaining portion 371 to prevent leakage of the first lubricant and the second lubricant from between them. The first seal 550 is made of, for example, a rubber sheet. The recovery tank 560 is provided below the first seal 550 and has an inlet 561 (see Figure 6) on its upper surface. The recovery tank 560 recovers the first lubricant and the second lubricant that have leaked from between the first flange 512 and the first retaining portion 371.

[0128] The first seal 550 has a ring portion 551 and a tongue portion 552. The ring portion 551 is provided in a ring shape between the first flange 512 and the first retaining portion 371. The tongue portion 552 protrudes downward from the ring portion 551 and is inserted into the inlet 561 of the recovery tank 560. The first lubricating oil and the second lubricating oil leak from between the first flange 512 and the first retaining portion 371 and are then guided into the recovery tank 560 by the tongue portion 552.

[0129] As mentioned above, the telescopic cover 500 is provided in pairs, sandwiching the cylinder 310 and screw 330, similar to the ball screw 380. The recovery tank 560 is located below the pair of telescopic covers 500 and recovers the first and second lubricants that leak from between the pair of first flanges 512 and the first retaining part 371. The recovery tank 560 may also serve as the discharge part 590.

[0130] An example of a cap nut will be described with reference to Figure 8. As shown in Figures 8(A) and 8(B), the first cover 510 has a third seal 514, a bolt 515A, and a nut 515B. The third seal 514 seals the space between the first frame 519 and the second cover 520. The third seal 514 is, for example, a rubber sheet. The bolt 515A and nut 515B secure the third seal 514 to the first frame 519.

[0131] As shown in Figure 8(A), when the nut 515B is fixed to the rear surface of the first frame 519, the third seal 514 is fixed to the front surface of the first frame 519. The third seal 514 is fixed by being sandwiched between the nut 515B and the head of the bolt 515A. The shaft of the bolt 515A is inserted into the through hole of the third seal 514 and the through hole of the first frame 519 and screwed onto the nut 515B. If the nut 515B is a cap nut, oil leakage can be suppressed.

[0132] As shown in Figure 8(B), when the nut 515B is fixed to the front of the first frame 519, the third seal 514 is fixed to the rear of the first frame 519. The third seal 514 is fixed by being sandwiched between the nut 515B and the head of the bolt 515A. The shaft of the bolt 515A is inserted into the through hole of the third seal 514 and the through hole of the first frame 519 and screwed onto the nut 515B. If the nut 515B is a cap nut, oil leakage can be suppressed.

[0133] As shown in Figure 8(C), the first cylinder 511 has a first split cylinder 511A and a second split cylinder 511B, as well as a first rib 511C. The first rib 511C protrudes upward from the second split cylinder 511B and is provided in pairs so as to sandwich the first split cylinder 511A. The first rib 511C is molded integrally with the second split cylinder 511B. As shown in Figure 6, the first rib 511C seals the lower end of the first split cylinder 511A from the outside, reducing the amount of first and second lubricating oil leaking from the dividing surface of the first split cylinder 511A and the second split cylinder 511B.

[0134] As shown in Figure 8(C), the first cylinder 511 has a bolt 511D and a nut 511E. The bolt 511D and nut 511E fix the first split cylinder 511A to a pair of first ribs 511C. The nut 511E is fixed to the inner circumferential surface of the first split cylinder 511A. The first split cylinder 511A is fixed by being sandwiched between the nut 511E and the head of the bolt 511D. The shaft of the bolt 511D is inserted into the through hole in the first rib 511C and the through hole in the first split cylinder 511A and screwed onto the nut 511E. If the nut 515B is a cap nut, oil leakage can be suppressed.

[0135] In addition to Figures 4 to 6, the second cover 520 will be described again with reference to Figure 9. The second cover 520 has a second cylinder 521. The second cylinder 521 protrudes from the second retaining portion 372 toward the first retaining portion 371. The second cylinder 521 has a third split cylinder 521A and a fourth split cylinder 521B provided below the third split cylinder 521A. By assembling the third split cylinder 521A and the fourth split cylinder 521B into a cylindrical shape, the ball screw shaft 381 and the ball screw nut 382 can be surrounded.

[0136] The third split cylinder 521A and the fourth split cylinder 521B are each constructed, for example, by bending sheet metal. The third split cylinder 521A and the fourth split cylinder 521B are assembled, for example, into a rectangular tube shape.

[0137] As shown in Figure 4, the ball screw shaft 381 inside the second cylinder 521 is covered by a ball screw nut 382. Therefore, the scattering of the first and second lubricating oils inside the second cylinder 521 is less than inside the first cylinder 511. Consequently, unlike the inside of the first cylinder 511, the inclined plate 518 and the inner cover 513 are not required inside the second cylinder 521.

[0138] The second cover 520 has a second flange 522, as shown in Figure 9. The second flange 522 is provided at the base end of the second cylinder 521 and is attached to the second retaining part 372 with bolts or the like. The second cylinder 521 and the second flange 522 may be divided in the same plane. The second flange 522 has a third split flange 522A and a fourth split flange 522B provided below the third split flange 522A. By assembling the third split flange 522A and the fourth split flange 522B into a ring shape, the ball screw shaft 381 and the ball screw nut 382 can be surrounded.

[0139] The third split flange 522A is provided at the base end of the third split cylinder 521A. The third split flange 522A is molded separately from the third split cylinder 521A and integrated with the third split cylinder 521A by welding or the like. The fourth split flange 522B is provided at the base end of the fourth split cylinder 521B. The fourth split flange 522B is molded separately from the fourth split cylinder 521B and integrated with the fourth split cylinder 521B by welding or the like. The dividing surfaces of the third split flange 522A and the fourth split flange 522B may be on the same plane as the dividing surfaces of the third split cylinder 521A and the fourth split cylinder 521B.

[0140] As shown in Figure 9, the second cylinder 521 has a second rib 521C in addition to the third split cylinder 521A and the fourth split cylinder 521B. The second rib 521C protrudes upward from the fourth split cylinder 521B and is provided in pairs so as to sandwich the third split cylinder 521A. The second rib 521C is molded integrally with the fourth split cylinder 521B. The second rib 521C seals the lower end of the third split cylinder 521A from the outside, reducing the amount of first and second lubricating oil leaking from the dividing surface of the third split cylinder 521A and the fourth split cylinder 521B.

[0141] Incidentally, as the second retaining portion 372 moves relative to the first retaining portion 371, a part of the second cylinder 521 moves in and out of the first cylinder 511. Therefore, the first lubricant and the second lubricant may drip from the inner circumferential surface of the first split cylinder 511A to the outer circumferential surface of the third split cylinder 521A, and further flow down the outer circumferential surface of the third split cylinder 521A.

[0142] Therefore, the second rib 521C has a recovery groove 521D for recovering the first and second lubricating oils that flow down the outer surface of the third splitting cylinder 521A, and a hole 521E for returning the first and second lubricating oils from the recovery groove 521D to the inside of the fourth splitting cylinder 521B. This prevents the first and second lubricating oils from flowing down the outer surface of the fourth splitting cylinder 521B along the circumferential direction.

[0143] As described above, the scattering of the first and second lubricants inside the second cylinder 521 is less than inside the first cylinder 511. However, when the second retaining part 372 moves relative to the first retaining part 371 and the volume of the expandable cover 500 decreases, the first and second lubricants may scatter towards the second flange 522 from the gap between the inner surface of the first cylinder 511 and the outer surface of the second cylinder 521.

[0144] Therefore, the injection device 300 is equipped with a guide 570, as shown in Figure 9. The guide 570 collects the first and second lubricating oils flowing down from the second flange 522 and directs them toward the oil pan 303 located below the second holding portion 372. This prevents oil leakage to unintended locations.

[0145] Incidentally, as described above, the telescopic cover 500 is provided in pairs, sandwiching the cylinder 310 and screw 330, similar to the ball screw 380. Therefore, a guide 570 is provided for each telescopic cover 500. The pair of guides 570 direct the first lubricant and the second lubricant towards the oil pan 303 located in the center. The oil pan 303 is provided, for example, on the slide base 301.

[0146] The above describes an example of applying the technology of this disclosure to an injection molding machine 300, but the technology of this disclosure can also be applied to a clamping machine 100 or an ejector machine 200.

[0147] While embodiments of the injection molding machine and injection apparatus according to the present invention have been described above, the present invention is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope described in the claims. These also naturally fall within the technical scope of the present invention. [Explanation of Symbols]

[0148] 10 injection molding machine 300 Injection device 371 1st holding part 372 Second holding part 380 Ball Screw 381 Ball screw shaft 382 Ball screw nut 383, 384 bearings 391 1st supply section 392 2nd supply section 500 Stretchable Cover 590 Discharge section

Claims

1. A ball screw including a ball screw shaft and a ball screw nut, A bearing that rotatably supports the aforementioned ball screw shaft, A first supply unit that supplies first lubricating oil to the bearing, A second supply unit that supplies a second lubricant to the ball screw nut, The first retaining portion that holds the bearing, A second retaining portion that holds the ball screw nut and moves relative to the first retaining portion along the ball screw axis, A retractable cover is provided between the first holding portion and the second holding portion, and expands and contracts due to the relative movement of the first holding portion and the second holding portion, A discharge unit that discharges the first lubricant and the second lubricant from the inside of the expandable cover to the outside through the discharge port of the expandable cover, An injection molding machine equipped with [a specific feature].

2. The injection molding machine according to claim 1, wherein the discharge port is provided below the rotational centerline of the ball screw shaft.

3. The expandable cover comprises a first cover provided on the first holding portion and a second cover provided on the second holding portion. The first cover has a first cylinder protruding from the first retaining portion toward the second retaining portion, and a first frame provided at the tip of the first cylinder and protruding from the inner circumferential surface of the first cylinder. The second cover has a second cylinder that protrudes from the second retaining portion toward the first retaining portion, The injection molding machine according to claim 1 or 2, wherein the first frame surrounds the second cylinder.

4. The first cover includes a third seal that closes the gap between the first frame and the second cover, and bolts and nuts that secure the third seal to the first frame. The injection molding machine according to claim 3, wherein the nut is a cap nut.

5. The expandable cover has a first cover provided on the first holding portion, The first cover has a first cylinder that protrudes from the first retaining portion toward the second retaining portion, The first cylinder comprises a first splitting cylinder and a second splitting cylinder provided below the first splitting cylinder. The first cover has an inclined plate provided inside the first cylinder and above the ball screw shaft, The injection molding machine according to claim 1 or 2, wherein the inclined plate is inclined downward as it approaches the first holding portion along the ball screw shaft.

6. The expandable cover has a first cover provided on the first holding portion, The first cover has a first cylinder protruding from the first retaining portion toward the second retaining portion, and a first flange provided at the base end of the first cylinder and attached to the first retaining portion. The first cylinder comprises a first splitting cylinder and a second splitting cylinder provided below the first splitting cylinder. The first flange comprises a first split flange and a second split flange provided below the first split flange. The injection molding machine according to claim 1 or 2, wherein the first cover is provided inside the first flange and has an inner cover that closes the dividing surface of the first split flange and the second split flange.

7. The expandable cover has a first cover provided on the first holding portion, The first cover has a first cylinder protruding from the first retaining portion toward the second retaining portion, and a first flange provided at the base end of the first cylinder and attached to the first retaining portion. The injection molding machine comprises a first seal provided between the first flange and the first retaining portion, and a recovery tank provided below the first seal and having an inlet on its upper surface. The injection molding machine according to claim 1 or 2, wherein the first seal has a ring portion provided between the first flange and the first retaining portion, and a tongue portion that protrudes downward from the ring portion and is inserted into the inlet of the recovery tank.

8. The expandable cover has a first cover provided on the first holding portion, The first cover has a first cylinder that protrudes from the first retaining portion toward the second retaining portion, The first cylinder comprises a first splitting cylinder, a second splitting cylinder provided below the first splitting cylinder, a pair of first ribs protruding upward from the second splitting cylinder and sandwiching the first splitting cylinder, and bolts and nuts for fixing the first splitting cylinder to the pair of first ribs. The injection molding machine according to claim 1 or 2, wherein the nut is a cap nut.

9. The expandable cover has a second cover provided on the second holding portion, The second cover has a second cylinder that protrudes from the second retaining portion toward the first retaining portion, The second cylinder has a third split cylinder, a fourth split cylinder provided below the third split cylinder, and a pair of second ribs that protrude upward from the fourth split cylinder and sandwich the third split cylinder. The injection molding machine according to claim 1 or 2, wherein the second rib has a recovery groove for collecting the first lubricant and the second lubricant that flows down the outer surface of the third split cylinder, and a hole for returning the first lubricant and the second lubricant from the recovery groove to the inside of the fourth split cylinder.

10. The expandable cover has a second cover provided on the second holding portion, The second cover has a second cylinder protruding from the second retaining portion toward the first retaining portion, and a second flange provided at the base end of the second cylinder and attached to the second retaining portion. The injection molding machine according to claim 1 or 2, wherein the injection molding machine is equipped with a guide that collects the first lubricating oil and the second lubricating oil flowing down from the second flange and directs them toward an oil pan provided below the second holding portion.

11. A ball screw including a ball screw shaft and a ball screw nut, A bearing that rotatably supports the aforementioned ball screw shaft, A first supply unit that supplies first lubricating oil to the bearing, A second supply unit that supplies a second lubricant to the ball screw nut, The first retaining portion that holds the bearing, A second retaining portion that holds the ball screw nut and moves relative to the first retaining portion along the ball screw axis, A retractable cover is provided between the first holding portion and the second holding portion, and expands and contracts due to the relative movement of the first holding portion and the second holding portion, A discharge unit that discharges the first lubricant and the second lubricant from the inside of the expandable cover to the outside through the discharge port of the expandable cover, An injection device equipped with [a specific feature].

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