Mold clamping device and its control method

Abstract

To provide a mold clamping device and its control method for more reliably fixing and holding a mold.SOLUTION: A mold clamping device 4 has a movable platen 21 and a fixed platen 22 arranged to face each other and moved relatively in the direction of approaching and moving away from each other, a hydraulic clamper device 40 equipped with a clamper capable of fixing an upper mold 31 to the movable platen 21, a hydraulic clamper device 40 equipped with a clamper capable of fixing a lower mold 32 to the fixed platen 22, and a pneumatic stopper device 80 equipped with a stopper capable of holding the upper mold 31 to the movable platen 21. The clamper and the stopper are driven by separate driving sources independent of each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a mold clamping device and a control method thereof. [Background technology]

[0002] There are known molding machines such as injection molding machines that supply molding material into a mold cavity to manufacture resin molded products and other molded products (hereinafter, sometimes collectively referred to as "molded products") of desired shapes. An injection molding machine is composed of a mold clamping device to which a mold is attached, and an injection device that injects the molding material into the mold cavity.

[0003] At a site where molded products are manufactured using an injection molding machine, the mold is changed depending on the molded product. More specifically, the mold that has been used until then is removed from the mold clamping device, and a different mold is attached to the mold clamping device.

[0004] That is, the mold clamping device is configured to be able to fix and release the mold. For example, one of the conventional mold clamping devices includes a fixed platen and a movable platen that is movable relative to the fixed platen. Each of the fixed platen and the movable platen is provided with a clamper. Each clamper is driven by hydraulic pressure or the like and is stroked between a position where the mold is fixed and a position where the mold is released. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 5-77245 Summary of the Invention [Problem to be solved by the invention]

[0006] It is desirable to more reliably fix and hold the mold by the mold clamping device.

[0007] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0008] According to one embodiment, the mold clamping device has a first mold mounting plate and a second mold mounting plate arranged opposite each other and moved relatively in an approaching direction and a separating direction, a first mechanical clamper capable of fixing a first mold to the first mold mounting plate, a second mechanical clamper capable of fixing a second mold to the second mold mounting plate, and a stopper capable of holding the first mold against the first mold mounting plate, and the first mechanical clamper, the second mechanical clamper and the stopper are driven by separate driving sources independent of each other. Effect of the Invention

[0009] According to one embodiment, the mold can be more reliably fixed and held by the mold clamping device. [Brief description of the drawings]

[0010] [Figure 1] 1 is a front view showing a schematic configuration of an injection molding machine according to an embodiment; [Diagram 2] 2 is a partially enlarged cross-sectional view of the mold clamping device taken along line XX in FIG. 1. [Figure 3A] 3 is a view of the mold clamping device taken along line AA in FIG. 2. [Figure 3B] 3 is a view of the mold clamping device taken along the line BB in FIG. 2. [Figure 4] FIG. 2 is an enlarged view showing the hydraulic clamper device according to the embodiment; [Diagram 5] FIG. 5 is a cross-sectional view of the hydraulic clamper device shown in FIG. [Figure 6] 5 is another cross-sectional view of the hydraulic clamper device shown in FIG. 4. [Figure 7] FIG. 2 is a system diagram showing a hydraulic system and a pneumatic system provided in the mold clamping device of the embodiment. [Figure 8] FIG. 2 is an enlarged view showing the pneumatic stopper device according to the embodiment; [Figure 9] FIG. 9 is a cross-sectional view of the pneumatic stopper device shown in FIG. 8. [Figure 10] 9 is another cross-sectional view of the pneumatic stopper device shown in FIG. 8. [Figure 11] 1 is a block diagram showing a configuration of a control device according to an embodiment of the present invention; [Figure 12] 4 is a flowchart illustrating an example of a control method executed by a control device according to an embodiment. [Figure 13] FIG. 11 is a front view showing a schematic configuration of an injection molding machine according to another embodiment. [Figure 14] 14 is a partially enlarged cross-sectional view of the mold clamping device taken along line YY in FIG. 13. [Figure 15A] 15 is a view of the mold clamping device taken along line CC in FIG. 14. [Figure 15B] 15 is a view of the mold clamping device taken along the line DD in FIG. 14. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments will be described in detail with reference to the drawings. In all drawings referred to in describing the embodiments, the same reference numerals are used for components and devices having the same or substantially the same functions. In addition, as a general rule, components and devices that have been described once will not be described repeatedly.

[0012] (First embodiment) 1 is a front view showing a schematic diagram of an injection molding machine 1A according to the present embodiment. The injection molding machine 1A has a base 2, an injection unit 3, a mold clamping unit 4, etc. In the following description, the "injection molding machine 1A" may be abbreviated to "molding machine 1A."

[0013] Here, with respect to the mold clamping unit 4 as a reference, the side where the injection unit 3 is arranged in Fig. 1 is defined as the "right side", and the side where the mold exchange cart 35 is arranged is defined as the "left side". However, this definition is merely for the convenience of explanation. The mold exchange cart 35 will be described later.

[0014] <Injection device> The injection device 3 melts and injects the molding material. In other words, the injection device 3 plasticizes and injects the molding material. In this embodiment, the injection device 3 melts and injects the resin material.

[0015] The injection device 3 includes a heating cylinder 10 and a hopper 11, and a screw is provided inside the heating cylinder 10. The screw is driven by a drive unit 12 controlled by a control device 70 described below. The drive unit 12 includes a drive source (for example, a metering motor and an injection motor) and rotates the screw and moves it forward and backward.

[0016] The resin material supplied to the heating cylinder 10 through the hopper 11 is melted by the shear heat generated by the rotation of the screw and the heat generated by the heater, and is stored in the heating cylinder 10. More specifically, the molten resin is stored in front of the screw in the heating cylinder 10. At this time, the screw retracts.

[0017] When a predetermined amount of molten resin is stored in the heating cylinder 10, the screw moves forward. Then, the molten resin stored in the heating cylinder 10 is pushed by the screw and injected from the nozzle 14.

[0018] <Mold clamping device> Fig. 2 is a partially enlarged cross-sectional view of the mold clamping device 4 taken along line XX in Fig. 1. Fig. 1 and Fig. 2 both show the mold clamping device 4 during mold opening. Fig. 3A is a view of the mold clamping device 4 taken along line AA in Fig. 2. Fig. 3B is a view of the mold clamping device 4 taken along line BB in Fig. 2.

[0019] The mold clamping device 4 includes a mold mounting platen 21 and a mold mounting platen 22 arranged opposite to each other. The mold mounting platen 21 and the mold mounting platen 22 face each other in the vertical direction. More specifically, the mold mounting platen 21 is arranged above the mold mounting platen 22 in the vertical direction. In other words, the mold mounting platen 22 is arranged below the mold mounting platen 21 in the vertical direction.

[0020] Tie bars 23 extend upward from the four corners of the mold mounting platen 22. Each tie bar 23 penetrates the four corners of the mold mounting platen 21 and is fixed to a support platen 24 (FIG. 1) disposed above the mold mounting platen 21. In other words, the positional relationship between the mold mounting platen 21 and the mold mounting platen 22 is determined by the four tie bars 23 that penetrate them.

[0021] 1, the mold mounting platen 21 is moved in a direction approaching the mold mounting platen 22 (downward) and in a direction moving away from the mold mounting platen 22 (upward). In other words, the mold mounting platen 21 moves up and down relative to the mold mounting platen 22.

[0022] Therefore, in the following description, the mold mounting platen 21 may be referred to as the "movable platen 21" and the mold mounting platen 22 may be referred to as the "fixed platen 22."

[0023] That is, the mold clamping unit 4 is a vertical mold clamping unit including a movable platen 21 and a fixed platen 22 that are arranged facing each other in the vertical direction and are relatively moved in a direction approaching and a direction separating them. Also, the molding machine 1A including the mold clamping unit 4 is a vertical injection molding machine.

[0024] The mold clamping unit 4 performs mold closing and mold opening by moving the movable platen 21 in the vertical direction. A mold opening and closing cylinder 25 is mainly used for mold closing and mold opening. The mold clamping unit 4 also performs mold clamping in addition to mold closing and mold opening. A mold clamping cylinder 26 is mainly used for mold clamping.

[0025] 1 shows two mold opening and closing cylinders 25. The cylinder barrel of each mold opening and closing cylinder 25 is fixed to the support platen 24, and the rod of each mold opening and closing cylinder 25 is fixed to the movable platen 21.

[0026] The mold opening and closing mechanism of the mold clamping device 4 may use an electric motor and a ball screw mechanism, etc., instead of the mold opening and closing cylinder 25. In addition, the number of mold opening and closing mechanisms is not limited to one or four (multiple).

[0027] On the other hand, the cylinder of the clamping cylinder 26 is disposed in the center of the support platen 24 and is fixed to the support platen 24. Also, the rod (ram) of the clamping cylinder 26 is fixed to the center of the upper surface of the movable platen 21.

[0028] When the clamping cylinder 26 is used in the clamping mechanism of the clamping device 4, the number of the clamping cylinders 26 is not limited to one or four (multiple). However, the clamping mechanism may be one that uses a toggle mechanism or a crank mechanism driven by an electric motor instead of the clamping cylinder 26.

[0029] <Mold> As shown mainly in Fig. 2, a mold 31 is attached to the movable platen 21, which is a mold mounting platen, and a mold 32 is attached to the other mold mounting platen, the fixed platen 22. In the following explanation, the mold 31 attached to the movable platen 21 may be referred to as the "upper mold 31," and the mold 32 attached to the fixed platen 22 may be referred to as the "lower mold 32." Furthermore, the upper mold 31 and the lower mold 32 may be collectively referred to as the "mold 30."

[0030] The mold 30 is composed of a mold body 33 and an attachment plate 34. A recess or a protrusion is provided on one surface (parting surface) of the mold body 33, and a temperature control piping is provided inside the mold body 33.

[0031] In this embodiment, a convex portion is provided on one surface of the mold body 33 of the upper mold 31, and a concave portion is provided on one surface of the mold body 33 of the lower mold 32. In other words, the upper mold 31 is a cavity mold, and the lower mold 32 is a core mold.

[0032] The temperature control piping forms a flow path inside the mold 30 through which temperature control water (cooling water) flows to cool the molten resin injected into the cavity. The temperature control water is supplied to the temperature control piping via a hose connected to the mold body 33. Therefore, when replacing the mold 30, a hose is connected to the mold body 33. Note that it is also possible to supply temperature control water (heated water) to the temperature control piping before replacing the mold 30, and heat the mold 30.

[0033] The mounting plate 34 is a plate portion having a predetermined thickness and an area larger than that of the mold body 33, and extends in a flange shape around the mold body 33. In another embodiment, a plurality of mold bodies are attached to a mounting plate having an area larger than that of the mounting plate 34.

[0034] In another embodiment, a hydraulic cylinder for a hot runner or a gate valve is provided in the mold 30. In this embodiment, when replacing the mold 30, in addition to the above-mentioned hoses, electric wiring and hydraulic oil piping are connected to the mold body 33.

[0035] The molded product is held by the upper die 31, and after the die is opened, it is released from the upper die 31 by an ejector device 27 (FIG. 1) provided on the movable platen 21.

[0036] <Mold exchange cart> 1 again, the die changing cart 35 is equipped with a die changing mechanism such as a fork 36 on which the die 30 is placed and a fork driving unit 37 that moves the fork 36 back and forth. The fork driving unit 37 is formed of, for example, a hydraulic cylinder or an electric motor.

[0037] When the mold 30 is carried into the mold clamping unit 4, the mold exchange cart 35 on which the mold 30 is mounted is parked next to the left side of the mold clamping unit 4. Next, the forks 36 are advanced and the mold 30 is inserted onto the fixed platen 22. In other words, the mold 30 is carried into the mold clamping unit 4 using the mold exchange mechanism. Note that in some embodiments, a positioning portion or a receiving portion that determines the carry-in position (insertion amount) of the mold 30 is provided on or around the fixed platen 22.

[0038] Thereafter, the mold 30 inserted onto the fixed platen 22 is supported from below by a lifter 28 (FIG. 2) built into the fixed platen 22. Thereafter, the forks 36 are moved backward to remove the mold 30 from the mold clamping unit 4.

[0039] On the other hand, when the mold 30 is to be removed from the mold clamping unit 4, the mold exchange cart 35 without the mold 30 mounted thereon is pulled up alongside the mold clamping unit 4. Next, the mold 30 removed from the fixed platen 22 is raised by the lifter 28 built into the fixed platen 22. After that, the forks 36 are moved forward and inserted under the mold 30. Next, the lifter 28 is lowered and the mold 30 is placed on the forks 36. Thereafter, the forks 36 are moved backward and the mold 30 is moved to the mold exchange cart 35. In other words, the mold 30 is removed (recovered) from the mold clamping unit 4.

[0040] However, the above-described replacement procedure is merely an example, and there are also embodiments in which the mold 30 is replaced without using the mold replacement cart 35. For example, in another embodiment, the mold 30 is carried into and out of the mold clamping unit 4 by using rolling elements (rollers or balls) provided on the fixed platen 22.

[0041] A locking mechanism may be provided to fix the upper die 31 and the lower die 32 so that they do not separate when the die 30 is carried in and out.

[0042] <Hydraulic clamper device> <Clamper> 3A, four hydraulic clamper devices 40 are provided on the movable platen 21. More specifically, two hydraulic clamper devices 40 are provided on the front side of the mold mounting surface 21a, and the other two hydraulic clamper devices 40 are provided on the rear side of the mold mounting surface 21a.

[0043] From another perspective, two hydraulic clamper units 40 are provided on one side of the path through which the mold 30 is carried in and out of the mold clamping unit 4, and other two hydraulic clamper units 40 are provided on the other side of the path through which the mold 30 is carried in and out of the mold clamping unit 4. The hydraulic clamper units 40 provided on the movable platen 21 include a mechanical clamper capable of fixing the mold.

[0044] 3B, the fixed platen 22 is also provided with four hydraulic clamper devices 40. The arrangement of the four hydraulic clamper devices 40 provided on the fixed platen 22 is the same as or substantially the same as the arrangement of the four hydraulic clamper devices 40 provided on the movable platen 21.

[0045] Specifically, two hydraulic clamper devices 40 are provided in front of the mold mounting surface 22a, and the other two hydraulic clamper devices 40 are provided behind the mold mounting surface 22a. The hydraulic clamper devices 40 provided on the fixed platen 22 include a mechanical clamper capable of fixing a mold.

[0046] All the hydraulic clamper devices 40 shown in Figures 3A and 3B have the same structure. Therefore, only one of the hydraulic clamper devices 40 shown in the figures will be described in detail, and detailed descriptions of the other hydraulic clamper devices 40 will be omitted.

[0047] Fig. 4 is an enlarged view showing one of the four hydraulic clamper devices 40 provided on the movable platen 21. Figs. 5 and 6 are cross-sectional views of the hydraulic clamper device 40 shown in Fig. 4.

[0048] As shown in Fig. 4, the hydraulic clamper device 40 includes a main body 41 and a clamper 42 that is reciprocatable relative to the main body 41. The clamper 42 is hydraulically driven and reciprocates between a position shown in Fig. 5 (advance position) and a position shown in Fig. 6 (retract position).

[0049] The main body 41 of the hydraulic clamper unit 40 is fixed by bolts to the mold mounting surface 21a of the movable platen 21. More specifically, the main body 41 is fixed at a position where its tip surface can face the side surface of the mounting plate 34 of the upper mold 31 attached to the mold clamping unit 4 with a small gap therebetween.

[0050] 5 and 6, a cylinder 43 is provided in the main body 41, and a steel piston 44 is accommodated in the cylinder 43 so as to be capable of reciprocating motion. The piston 44 includes a head portion 44a and a rod portion 44b.

[0051] The head portion 44a of the piston 44 divides the inside of the cylinder 43 into two oil chambers 43a, 43b. The front portion of the rod portion 44b of the piston 44 has a wedge shape and forms a clamper 42 including a pressing surface 45.

[0052] A forward port 46a communicating with the oil chamber 43a and a reverse port 46b communicating with the oil chamber 43b are provided on the side wall of the main body 41. When hydraulic oil is supplied to the oil chamber 43a shown in Fig. 6 through the forward port 46a, the piston 44 is pushed out, and the clamper 42 moves from the backward position (Fig. 6) to the forward position (Fig. 5).

[0053] On the other hand, when hydraulic oil is supplied to the oil chamber 43b shown in Fig. 5 through the reverse side port 46b shown in the same figure, the piston 44 is pushed back, and the clamper 42 moves from the forward position (Fig. 5) to the backward position (Fig. 6). In other words, the hydraulic clamper device 40 is a double-acting hydraulic cylinder.

[0054] A coil spring 47 is disposed between the bottom of the cylinder 43 and the head portion 44a. One end of the coil spring 47 abuts against the bottom surface of the cylinder 43, and the other end of the coil spring 47 is inserted into an insertion hole 48 provided in the head portion 44a.

[0055] The coil spring 47 constantly biases the piston 44 forward (to the forward position), so that the clamper 42 is held in the forward position even when hydraulic oil is not supplied to both the oil chambers 43a and 43b.

[0056] As described above, the other hydraulic clamper device 40 has the same structure as the above hydraulic clamper device 40, and operates in the same manner as the above hydraulic clamper device 40. However, the main body 41 of the hydraulic clamper device 40 provided on the fixed platen 22 is fixed to the upper surface (mold mounting surface 22a) of the fixed platen 22 by bolts.

[0057] 5, when the clamper 42 of the hydraulic clamper unit 40 provided on the movable platen 21 moves to the forward position, it abuts against the mounting plate 34 of the upper die 31 and presses the mounting plate 34. More specifically, the pressing surface 45 of the clamper 42 abuts against the clamper abutment surface on the lower surface of the mounting plate 34 and presses up the mounting plate 34. As a result, the platen abutment surface of the mounting plate 34 is pressed against the mold mounting surface 21a of the movable platen 21, and the upper die 31 is fixed to the movable platen 21.

[0058] 6, when the clamper 42 of the hydraulic clamper unit 40 provided on the movable platen 21 moves to the retreated position, it moves away from the clamper abutment surface of the mounting plate 34 of the upper die 31 and retreats to the periphery of the upper die 31. As a result, the mounting plate 34 is released from pressing against the die mounting surface 21a of the movable platen 21. In other words, the upper die 31 is released from the fixed state to the movable platen 21.

[0059] The clamper 42 of the hydraulic clamper device 40 provided on the fixed platen 22 fixes and releases the lower mold 32 to and from the fixed platen 22 by substantially the same operation as the clamper 42 of the hydraulic clamper device 40 provided on the movable platen 21.

[0060] Specifically, when the clamper 42 of the hydraulic clamper unit 40 provided on the fixed platen 22 moves to the forward position, it abuts against the mounting plate 34 of the lower die 32 and presses down the mounting plate 34. More specifically, the pressing surface 45 of the clamper 42 abuts against the clamper abutment surface on the upper surface of the mounting plate 34 and presses down the mounting plate 34. As a result, the platen abutment surface of the mounting plate 34 is pressed against the die mounting surface 22a of the fixed platen 22, and the lower die 32 is fixed to the fixed platen 22.

[0061] On the other hand, when the clamper 42 of the hydraulic clamper unit 40 provided on the fixed platen 22 moves to the retreated position, it leaves the clamper abutment surface of the mounting plate 34 of the lower die 32 and retreats to the periphery of the lower die 32. As a result, the mounting plate 34 is released from pressing against the die mounting surface 22a of the fixed platen 22. In other words, the lower die 32 is released from the fixed platen 22.

[0062] As described above, the four clampers 42 provided on the movable platen 21 are capable of reciprocating between a forward position in which the upper die 31 is fixed and a retracted position in which the upper die 31 is spaced further away from the upper die 31 than the forward position and in which the upper die 31 is not fixed.

[0063] Similarly, the four clampers 42 provided on the fixed platen 22 are capable of reciprocating between an advanced position in which the lower die 32 is fixed and a retracted position in which the clampers are spaced further away from the lower die 32 than the advanced position and do not fix the lower die 32.

[0064] Furthermore, the eight clampers 42 are mechanical clampers that contact the mold 30 to fix it. In the present invention, a hydraulically driven mechanical clamper is one in which a hydraulic cylinder, which is a driving unit, is operated to press, engage, clamp, hold, etc. at least a part of the mold, thereby fixing the mold to the mold mounting platen. Therefore, a clamper that fixes a mold to the mold mounting platen simply by the magnetic force of an electromagnet is excluded from the definition of a mechanical clamper. Furthermore, the number of mechanical clampers provided on the mold mounting platen may be two or more, and is not limited.

[0065] <Clamper position detection unit> 4, the hydraulic clamper device 40 is equipped with a clamper position detector 50 that detects the position of the clamper 42. The clamper position detector 50 is composed of a protrusion 51 provided on the piston 44 and a limit switch 52 provided on the main body 41. The protrusion 51 is, for example, the head of a bolt that is screwed to the piston 44.

[0066] A protrusion 51 provided on the piston 44 protrudes to the outside of the main body 41 through a slit 53 formed in the side wall of the main body 41. As a result, the protrusion 51 reciprocates within the slit 53 in the longitudinal direction of the slit 53 as the clamper 42 advances and retreats.

[0067] The limit switch 52 is fixed to the side of the main body 41, and the actuator 52a of the limit switch 52 extends across the slit 53. Therefore, the convex portion 51, which moves within the slit 53 as the clamper 42 advances, comes into contact with the actuator 52a in the process, gradually pushing up the actuator 52a. When the clamper 42 reaches the forward position, the contacts of the limit switch 52 are closed, and a detection signal is output. As a result, the movement of the clamper 42 to the forward position is detected.

[0068] On the other hand, when the clamper 42 moves to the retracted position, the actuator 52a is released from the protrusion 51. Then, the contacts of the limit switch 52 are opened and the detection signal is discontinued. As a result, the movement of the clamper 42 to the retracted position is detected.

[0069] However, there is also an embodiment in which, when the clamper 42 moves to the retreated position, another contact of the limit switch 52 is closed (the contact is switched) and a detection signal is output.

[0070] Furthermore, the pushing up of the actuator 52a by the convex portion 51 may be released before the clamper 42 moves (reaches) the retracted position. For example, when the clamper 42 moves to an intermediate position between the advanced position and the retracted position, the pushing up of the actuator 52a by the convex portion 51 may be released. In this case, the clamper position detection unit 50 detects that the clamper 42 has moved away from the advanced position.

[0071] The configuration of the clamper position detection unit 50 is not limited to the above. For example, the limit switch 52 may be a plunger type, hinge type, roller type, or rod type instead of the lever type described above. Also, instead of a mechanical switch such as the limit switch 52, the clamper position detection unit 50 may be configured by a non-mechanical switch (proximity switch) such as a magnetic sensor or an optical sensor.

[0072] <Hydraulic system> The mold clamping unit 4 is equipped with a hydraulic system for operating the hydraulic clamper unit 40 as described above. Fig. 7 is a system diagram showing the hydraulic system and the pneumatic system of the mold clamping unit 4. The pneumatic system will be described later.

[0073] The hydraulic system is composed of an oil tank 60, a pump 61, and a group of hydraulic control devices 62. Between the pump 61 and each hydraulic clamper device 40, a flow path for hydraulic oil is formed by piping, and a group of hydraulic control devices 62 is arranged on each flow path.

[0074] More specifically, independent flow paths are formed between the pump 61 and each hydraulic clamper device 40. Hydraulic control devices such as a check valve 63, a pressure control valve 64, a directional control valve 65, and a pressure switch 66 are disposed on each flow path.

[0075] The hydraulic control device group 62 is controlled by the control device 70. The control device 70 supplies hydraulic oil to either one of the oil chambers 43a, 43b of the hydraulic clamper device 40 (cylinder tube 43) by, for example, switching the directional control valve 65. As described above, when hydraulic oil is supplied to either one of the oil chambers 43a, 43b, the clamper 42 advances and retreats.

[0076] The pressure (hydraulic pressure) of the hydraulic oil supplied to the hydraulic clamper device 40 (cylinder tube 43) under the control of the control device 70 is detected by a pressure switch 66 and fed back to the control device 70. More specifically, when the pressure of the hydraulic oil exceeds a threshold value, the pressure switch 66 is actuated, and an interlock circuit is configured in which a detection signal is input to the control device 70. The details of the control device 70 will be described later.

[0077] Although the driving source of the pump 61 is not particularly limited, the pump 61 in this embodiment is driven by a servo motor. The pump 61 supplies hydraulic oil not only to the hydraulic clamper device 40 but also to other hydraulic devices (for example, the mold opening / closing cylinder 25 and the mold clamping cylinder 26).

[0078] In addition, the mechanical clamper that fixes the upper die 31 attached to the movable platen 21 may have the following configuration in case of failure of the hydraulic control device group 62, such as the check valve 63, pressure control valve 64, directional control valve 65, and pressure switch 66. That is, a configuration may be adopted in which hydraulic oil is supplied to one hydraulic clamper device 40 via a plurality of (for example, two) hydraulic control device groups 62. With this configuration, even if the directional control valve 65 or its signal line of one hydraulic control device group 62 is inoperative due to a failure, hydraulic oil can be continuously supplied to the oil chamber 43a of a specific hydraulic clamper device 40 via another hydraulic control device group 62. <Air pressure stopper device> Stopper 3A, the movable platen 21, which is a mold mounting platen, is provided with a pair of pneumatic stopper devices 80 capable of holding the upper mold 31. More specifically, one pneumatic stopper device 80 is provided on the front side of the mold mounting surface 21a, and the other pneumatic stopper device 80 is provided on the rear side of the mold mounting surface 21a.

[0079] The two pneumatic stopper devices 80 are offset from each other with respect to the center P of the die 30 (upper die 31). More specifically, the pneumatic stopper device 80 provided on the front side of the die mounting surface 21a is offset to the left with respect to the center P of the die 30 (upper die 31). On the other hand, the pneumatic stopper device 80 provided on the rear side of the die mounting surface 21a is offset to the right with respect to the center P of the die 30 (upper die 31).

[0080] In other words, the two pneumatic stopper devices 80 are positioned symmetrically with respect to the center P of the die 30 (upper die 31).

[0081] The two pneumatic stopper devices 80 shown in the figure have the same structure, so only one of the pneumatic stopper devices 80 will be described in detail, and a detailed description of the other pneumatic stopper device 80 will be omitted.

[0082] Fig. 8 is an enlarged view showing one of the two pneumatic stopper devices 80 provided on the movable platen 21. Figs. 9 and 10 are cross-sectional views of the pneumatic stopper device 80 shown in Fig. 8.

[0083] As shown in Fig. 8, the pneumatic stopper device 80 includes a main body 81 and a stopper 82 that is reciprocable relative to the main body 81. The stopper 82 is driven by air pressure, and reciprocates between a position shown in Fig. 9 (advance position) and a position shown in Fig. 10 (retract position).

[0084] The main body 81 includes a bracket 83 and an air cylinder 84, and is fixed to the mold mounting surface 21a of the movable platen 21. More specifically, the main body 81 is fixed at a position where its tip surface (the tip surface of the bracket 83) can face the side surface of the mounting plate 34 of the upper mold 31 attached to the mold clamping device 4 with a small gap therebetween.

[0085] The air cylinder 84 includes a cylinder tube 85 and a steel piston 86 that is reciprocally housed within the cylinder tube 85. The cylinder tube 85 is fixed to the bracket 83 by a rod that passes through flanges disposed on both sides of the cylinder tube 85 in the longitudinal direction.

[0086] 9 and 10, the piston 86 includes a head portion 86a and a rod portion 86b. The head portion 86a of the piston 86 divides the inside of the cylinder 85 into two air chambers 85a and 85b. The front portion of the rod portion 86b of the piston 86 is plate-shaped and forms the stopper 82 including a holding surface 87.

[0087] A forward port 88a communicating with the air chamber 85a and a reverse port 88b communicating with the air chamber 85b are provided on the side wall of the cylinder 85. When compressed air is supplied to the air chamber 85a shown in Fig. 10 through the forward port 88a, the piston 86 is pushed out and the stopper 82 moves from the backward position (Fig. 10) to the forward position (Fig. 9).

[0088] On the other hand, when compressed air is supplied to the air chamber 85b shown in Fig. 9 through the reverse side port 88b shown in the same figure, the piston 86 is pushed back, and the stopper 82 moves from the forward position (Fig. 9) to the backward position (Fig. 10). In other words, the pneumatic stopper device 80 is a double-acting air cylinder.

[0089] 9, when the stopper 82 of the pneumatic stopper device 80 moves to the forward position, it enters below the mounting plate 34 of the upper die 31. As a result, at least the holding surface 87 of the stopper 82 is disposed vertically below the mounting plate 34 of the upper die 31.

[0090] Therefore, the upper die 31, which is no longer fixed by the clamper 42, which is a mechanical clamper, abuts against and is held by at least the holding surface 87 of the stopper 82. More specifically, the lower surface (the same plane as the clamper abutment surface) of the mounting plate 34 of the upper die 31, which is no longer fixed by the clamper 42, is received by the holding surfaces 87 of the two stoppers 82 and supported from below in the vertical direction. In other words, even if the upper die 31 is no longer fixed by the clamper 42, the upper die 31 will not immediately come off (fall) from the movable platen 21.

[0091] As described above, the tip surface of the hydraulic clamper device 40 (main body 41) and the tip surface of the pneumatic stopper device 80 (main body 81) face the side surface of the mounting plate 34 of the upper mold 31 with a small gap therebetween.

[0092] Therefore, the mounting plate 34 of the upper mold 31 is sandwiched between the front hydraulic clamper device 40 and the pneumatic stopper device 80 and the rear hydraulic clamper device 40 and the pneumatic stopper device 80, and cannot rotate between them (see Figure 3A).

[0093] As a result, even if the fixation by all the clampers 42 is released, the upper die 31 can be stably held by only the two stoppers 82. The stoppers 82 only need to have the ability and strength to hold the upper die 31 so as not to fall. From another perspective, the stoppers 82 do not need to have the ability and strength to support the upper die 31 during normal continuous molding. For example, the stoppers 82 do not need to have the ability and strength to support the upper die 31 when the upper die 31 is released from the lower die 32. Therefore, by minimizing the number and capabilities of the stoppers 82, costs can be reduced.

[0094] Furthermore, in this embodiment, the two stoppers 82 are offset from each other with respect to the center P of the upper die 31. Therefore, the upper die 31 does not rotate with either one of the stoppers 82 as a fulcrum. Therefore, the upper die 31 can be more stably held by only the two stoppers 82. However, it is not excluded that three or more stoppers 82 are provided on the movable platen 21. In that case, the stoppers 82 are provided in pairs on both sides of the upper die 31, and it is preferable that the total number of stoppers 82 is an even number, but it is not excluded that the total number of stoppers 82 is an odd number.

[0095] Furthermore, when the stoppers 82 are provided in pairs, as long as at least one of the stoppers 82 is driven by a driving source such as air pressure, the other stopper 82 may not be provided with a driving source and may only have a receiving portion capable of holding the upper die 31. Furthermore, both stoppers 82 may be driven by a single driving source via a link mechanism or the like.

[0096] The holding surface 87 of the stopper 82 that has moved to the advanced position faces the lower surface of the mounting plate 34 with a small gap (for example, 1 mm) therebetween. From another perspective, the stopper 82 that has moved to the advanced position waits at a position slightly separated from the mounting plate 34 so as to be able to hold the upper die 31.

[0097] The above-mentioned gap (clearance) existing between the mounting plate 34 and the stopper 82 (holding surface 87) prevents interference between the mounting plate 34 and the stopper 82, ensuring smooth advancement and retreat of the stopper 82.

[0098] However, in another embodiment, all or a part of the stopper 82 that has been moved to the forward position can abut against the upper die 31 at all times or at least during die clamping.

[0099] 10, when the stoppers 82 of the pneumatic stopper device 80 move to the retracted position, they retreat to the periphery of the upper die 31. In other words, the two stoppers 82 provided on the movable platen 21 are capable of reciprocating between an advanced position where they hold the upper die 31 and a retracted position where they are farther away from the upper die 31 than the advanced position and do not hold the upper die 31.

[0100] From another perspective, in order to separate the upper die 31 from the movable platen 21, at least two conditions (movement of the clamper 42 to the retracted position and movement of the stopper 82 to the retracted position) must be satisfied.

[0101] <Stopper position detection unit> 8, the pneumatic stopper device 80 is equipped with a stopper position detector 90 that detects the position of the stopper 82. The stopper position detector 90 is composed of a protrusion 91 provided on the piston 86 and two proximity switches 92, 93 provided on the main body 81 (bracket 83). The protrusion 91 is, for example, a cam provided on the piston 86.

[0102] A protrusion 91 provided on the piston 86 protrudes to the outside of the bracket 83 through a slit 94 formed in the side wall of the bracket 83. As a result, the protrusion 91 reciprocates within the slit 94 in the longitudinal direction of the slit 94 as the stopper 82 advances and retreats.

[0103] The proximity switches 92, 93 are fixed to the side surfaces of the bracket 83. The proximity switches 92, 93 are spaced apart from each other in the longitudinal direction of the slit 94.

[0104] When the stopper 82 moves to the forward position, the protrusion 91 is detected by one of the proximity switches 92, and a detection signal is output. When the stopper 82 moves to the backward position, the protrusion 91 is detected by the other of the proximity switches 93, and a detection signal is output. As a result, the movement of the stopper 82 to the forward position or the backward position is detected.

[0105] However, the configuration of the stopper position detection unit 90 is not limited to the above configuration. For example, the proximity switches 92, 93 can be replaced with a mechanical switch such as the limit switch 52 or other non-contact switches.

[0106] Also, it may be determined that the stopper 82 has left the forward position when the signal output from the proximity switch 92 is interrupted. In this case, the arrival of the stopper 82 at the forward position and the departure of the stopper 82 from the forward position can be detected by the proximity switch 92 alone.

[0107] <Pneumatic system> As already described, the mold clamping unit 4 is equipped with the pneumatic system shown in Fig. 7. The pneumatic system is composed of the air compressor 100, the pneumatic control device group 101, etc. More specifically, a compressed air flow path is formed by piping between the air compressor 100 and the two pneumatic stopper devices 80, and the pneumatic control device group 101 is arranged on the flow path.

[0108] The pneumatic control device group 101 includes at least a pressure control valve 102 , a directional control valve 103 , a flow control valve 104 , and a check valve 105 .

[0109] The pneumatic control device group 101 is controlled by the control device 70. The control device 70 supplies compressed air to the air chambers 85a, 85b of the pneumatic stopper device 80 (air cylinder 84) by, for example, switching the directional control valve 103. As described above, when compressed air is supplied to the air chambers 85a, 85b, the stopper 82 advances and retreats.

[0110] The clamper 42 is driven by hydraulic pressure, whereas the stopper 82 is driven by air pressure. In other words, the clamper 42 and the stopper 82 are driven by separate drive sources that are independent of each other. Furthermore, the hydraulic system for operating the clamper 42 and the air system for operating the stopper 82 are also independent of each other.

[0111] Therefore, even if some kind of failure occurs in the hydraulic system, the stopper 82 will not be affected in any way and can operate normally.

[0112] However, the drive source of the stopper 82 is not limited to air pressure as long as it is independent of the drive source of the clamper 42. For example, the drive source of the stopper 82 may be changed to hydraulic pressure, and the stopper 82 may be operated by a hydraulic system independent of the hydraulic system for operating the clamper 42. Also, the stopper 82 may be driven by an electric cylinder or an electric motor.

[0113] <Control device> Next, a description will be given of the control device 70 shown in Fig. 7. The control device 70 comprehensively controls the molding machine 1A including the injection device 3 and the mold clamping device 4. Fig. 11 is a block diagram showing the configuration of the control device 70.

[0114] The control device 70 includes a controller 71, an input interface 72, and an output interface 73. The controller 71 includes a CPU, a memory, and the like that are communicably connected to each other.

[0115] Various detection signals and information are input to the controller 71 via the input interface 72. The controller 71 processes the input detection signals and information according to a program stored in memory, and generates command signals based on the processing results. The controller 71 outputs the generated command signals to various devices and equipment via the output interface 73.

[0116] As already mentioned, the detection signal output from the pressure switch 66 shown in FIG. 7 is input to the control device 70, but more specifically, the detection signal output from the pressure switch 66 is input to the controller 71 via the input interface 72.

[0117] Further, the controller 71 also receives a detection signal output from the limit switch 52 shown in FIG. 4 and detection signals output from the proximity switches 92 and 93 shown in FIG.

[0118] Meanwhile, the controller 71 outputs command signals to devices constituting the hydraulic system and the pneumatic system to control the hydraulic clamper device 40 and the pneumatic stopper device 80. For example, the controller 71 switches the directional control valve 65 of the hydraulic system to advance and retreat the clamper 42. The controller 71 also switches the directional control valve 103 of the pneumatic system to advance and retreat the stopper 82.

[0119] Furthermore, the controller 71 also outputs command signals to the drive unit 12 and the notification unit 15 of the injection device 3. The notification unit 15 is, for example, a monitor capable of displaying a message or a speaker capable of generating a warning sound.

[0120] <Control method> Fig. 12 is a flowchart showing an example of a control method executed by the control device 70. In step S1 shown in Fig. 12, it is determined whether or not the clampers 42 of all the hydraulic clamper devices 40 have moved to the forward positions. Specifically, it is determined whether or not detection signals are being output from all the limit switches 52.

[0121] If it is determined in step S1 that the clampers 42 of some or all of the hydraulic clamper devices 40 have not moved to the forward position, the process proceeds to step S5. Specifically, if it is determined that the detection signals are not being output from some or all of the limit switches 52, the process proceeds to step S5.

[0122] In step S5, a command signal is output to the notification unit 15. The notification unit 15 that has received the command signal displays a warning message or emits a warning sound in accordance with the command.

[0123] On the other hand, if it is determined in step S1 that the clampers 42 of all the hydraulic clamper devices 40 have been moved to the forward position, the process proceeds to step S2.

[0124] In step S2, it is determined whether the pressure in the oil chambers 43a of all the hydraulic clamper devices 40 is rising or not. From another perspective, it is determined whether hydraulic oil with a pressure exceeding the threshold value is being supplied to all the hydraulic clamper devices 40. Specifically, it is determined whether detection signals are being output from all the pressure switches 66.

[0125] If it is determined in step S2 that the pressure in the oil chambers 43a of some or all of the hydraulic clamper devices 40 has not risen sufficiently, the process proceeds to step S5. Specifically, if it is determined that the detection signals are not being output from some or all of the pressure switches 66, the process proceeds to step S5.

[0126] On the other hand, if it is determined in step S2 that hydraulic oil with a pressure exceeding the threshold value is being supplied to all of the hydraulic clamper devices 40, the process proceeds to step S3.

[0127] In step S3, it is determined whether the stoppers 82 of the two pneumatic stopper devices 80 have moved to the forward position. Specifically, it is determined whether detection signals are being output from both of the two proximity switches 92.

[0128] If it is determined in step S3 that the stoppers 82 of one or both of the pneumatic stopper devices 80 have not moved to the forward position, the process proceeds to step S5. Specifically, if it is determined that the detection signal is not being output from one or both of the proximity switches 92, the process proceeds to step S5.

[0129] On the other hand, when it is determined in step S3 that the stoppers 82 of the two pneumatic stopper devices 80 have moved to the forward position, the process proceeds to step S4, where the relative movement between the movable platen 21 and the fixed platen 22 is permitted. Specifically, the supply of hydraulic oil to the mold opening and closing cylinder 25 is permitted.

[0130] In the above control method, operations such as mold opening and closing are not performed unless at least three conditions (movement of the clamper 42 to the forward position, pressure rise in the oil chamber 43a, and movement of the stopper 82 to the forward position) are satisfied. From another perspective, the mold clamping unit 4 has an interlock function that does not permit operations such as mold opening and closing unless all of the above three conditions are satisfied.

[0131] 11 can function as an interlock control unit or a command signal generating unit, and the memory can function as a sequence circuit storage unit. It can also be understood that the input interface 72 can function as a signal input unit, and the output interface 73 can function as a signal output unit.

[0132] The positions of the clamper 42 and the stopper 82 may be continuously monitored even while the molded product is being manufactured. In this case, when it is no longer detected that the clamper 42 and the stopper 82 are in the forward position, the control device 70 immediately executes step S5 and stops the operation of the molding machine 1A.

[0133] Second embodiment Fig. 13 is a front view showing a schematic diagram of an injection molding machine 1B according to the present embodiment. The injection molding machine 1B has substantially the same basic configuration as the molding machine 1A shown in Fig. 1. Therefore, a description of the same or substantially the same configuration as the molding machine 1A will be omitted, and differences from the molding machine 1A will be mainly described. In the following description, "injection molding machine 1B" may be abbreviated to "molding machine 1B".

[0134] The mold clamping device 4 of the molding machine 1A is a vertical mold clamping device, and therefore the molding machine 1A is a vertical injection molding machine. On the other hand, the mold clamping device 4 according to the present embodiment is a horizontal mold clamping device, and therefore the molding machine 1B is a horizontal injection molding machine.

[0135] <Mold clamping device> The movable platen 21 and the fixed platen 22 included in the mold clamping unit 4 according to this embodiment face each other in the horizontal direction. More specifically, the movable platen 21 is disposed on the left side of the fixed platen 22 in the horizontal direction. In other words, the fixed platen 22 is disposed on the right side of the movable platen 21 in the horizontal direction.

[0136] The positional relationship between the movable platen 21 and the fixed platen 22 is determined by four tie bars 23 extending horizontally (left and right). The movable platen 21 is moved by the mold opening and closing mechanism 110 in a direction approaching the fixed platen 22 (right side) and in a direction away from the fixed platen 22 (left side).

[0137] The mold opening and closing mechanism 110 is a servo mechanism. More specifically, the mold opening and closing mechanism 110 has a servo motor 111, a screw shaft 112, a nut 113, etc. The screw shaft 112 is supported at both ends by bearings (ball bearings) and is rotationally driven by the servo motor 111.

[0138] When the screw shaft 112 is rotationally driven by the servo motor 111, the movable platen 21 moves left and right. That is, the movable platen 21 and the fixed platen 22 are moved relatively in the direction approaching and in the direction separating by the mold opening and closing mechanism 110.

[0139] The servo motor 111 is controlled by the control device 70 via a servo amplifier. As a result, the mold 31 fixed to the movable platen 21 by the hydraulic clamper device 40 is moved relative to the mold 32 fixed to the fixed platen 22 by the hydraulic clamper device 40, and mold opening and closing are performed. Fig. 13 shows the mold open state. Note that mold clamping is performed by a mold clamping cylinder and a toggle mechanism of a mold clamping mechanism (not shown).

[0140] <Hydraulic clamper device and pneumatic stopper device> Fig. 14 is a partially enlarged cross-sectional view of the mold clamping device 4 taken along line YY in Fig. 13. Fig. 15A is a view of the mold clamping device 4 taken along line CC in Fig. 14. Fig. 15B is a view of the mold clamping device 4 taken along line DD in Fig. 14.

[0141] The movable platen 21, which is a mold mounting platen, is provided with four hydraulic clamper devices 40 equipped with mechanical clampers capable of fixing the mold 31 (movable mold). More specifically, two hydraulic clamper devices 40 are provided above the mold mounting surface 21a, and the other two hydraulic clamper devices 40 are provided below the mold mounting surface 21a.

[0142] Similarly, the fixed platen 22, which is a mold mounting platen, is provided with four hydraulic clamper devices 40 equipped with mechanical clampers capable of fixing the mold 32 (fixed mold). More specifically, two hydraulic clamper devices 40 are provided above the mold mounting surface 22a, and the other two hydraulic clamper devices 40 are provided below the mold mounting surface 22a.

[0143] Furthermore, the movable platen 21 is provided with two pneumatic stopper devices 80 capable of holding the die 31, and the fixed platen 22 is provided with two pneumatic stopper devices 80 capable of holding the die 32. More specifically, two pneumatic stopper devices 80 are provided above the die mounting surface 21a, and two pneumatic stopper devices 80 are also provided above the die mounting surface 22a.

[0144] The two pneumatic stopper devices 80 provided on the movable platen 21 are disposed between the two hydraulic clamper devices 40 provided on the upper side of the movable platen 21. Similarly, the two pneumatic stopper devices 80 provided on the fixed platen 22 are disposed between the two hydraulic clamper devices 40 provided on the upper side of the fixed platen 22.

[0145] The hydraulic clamper device 40 and the pneumatic stopper device 80 of this embodiment are connected to substantially the same hydraulic system and pneumatic system as those shown in Fig. 7. However, the mold clamping device 4 according to this embodiment is provided with four pneumatic stopper devices 80. Therefore, the number of branches of the pneumatic system is increased according to the number of pneumatic stopper devices 80.

[0146] Stopper 82 of pneumatic stopper device 80 provided on movable platen 21 shown in Fig. 15B protrudes in front of mounting plate 34 of mold 31 when moved to the forward position. Also, stopper 82 of pneumatic stopper device 80 provided on fixed platen 22 shown in Fig. 15A protrudes in front of mounting plate 34 of mold 32 when moved to the forward position.

[0147] Therefore, the upper part of the mold 31, which is no longer fixed by the clamper 42, is held by the two stoppers 82. Similarly, the upper part of the mold 32, which is no longer fixed by the clamper 42, is also held by the two stoppers 82.

[0148] More specifically, even if the upper part (part of the mounting plate 34) of the mold 31, which is no longer fixed by the clamper 42, moves in a direction away from the mold mounting surface 21a, it is received by the holding surfaces 87 of the two stoppers 82. Also, even if the upper part (part of the mounting plate 34) of the mold 32, which is no longer fixed by the clamper 42, moves in a direction away from the mold mounting surface 22a, it is received by the holding surfaces 87 of the other two stoppers 82.

[0149] Therefore, even if the dies 31 and 32 are no longer fixed by the clamper 42, the dies 31 and 32 will not immediately separate from the movable platen 21 (fall down).

[0150] The two pneumatic stopper devices 80 provided on the movable platen 21 are offset from each other with respect to the center P of the die 31. Similarly, the two pneumatic stopper devices 80 provided on the fixed platen 22 are also offset from each other with respect to the center P of the die 32.

[0151] More specifically, one pneumatic stopper device 80 provided on the movable platen 21 shown in FIG. 15B is offset to the front side (operation side) with respect to the center P of the mold 31, and the other pneumatic stopper device 80 is offset to the rear side (anti-operation side) with respect to the center P of the mold 31.

[0152] In addition, one of the pneumatic stopper devices 80 provided on the fixed platen 22 shown in FIG. 15A is offset to the front side (operation side) with respect to the center P of the mold 32, and the other pneumatic stopper device 80 is offset to the rear side (anti-operation side) with respect to the center P of the mold 32.

[0153] Therefore, the die 31 does not rotate around either of the stoppers 82, and the die 32 does not rotate around either of the stoppers 82. Therefore, even if the clamper 42 is in the retracted position for some reason, the dies 31 and 32 are stably held by the lower hydraulic clamper device 40 with the clamper 42 in the retracted position and the stopper 82.

[0154] The prevention of rotation of the dies 31, 32 as described above can also be achieved by relocating the pneumatic stopper device 80 to another position. For example, the rotation of the die 31 can also be prevented by relocating at least one of the pneumatic stopper devices 80 to the upper front side or upper rear side of the movable platen 21. Similarly, the rotation of the die 32 can also be prevented by relocating at least one of the pneumatic stopper devices 80 to the upper front side or upper rear side of the fixed platen 22.

[0155] In addition, in Figures 15A and 15B, the pneumatic stopper device 80 relocated to the upper front and upper rear sides of the fixed platen 22 and the movable platen 21 is shown by virtual lines (dash lines), but the position of the pneumatic stopper device 80 is not limited to the position shown in the figures.

[0156] Although the invention made by the present inventor has been specifically described based on the embodiment, the present invention is not limited to the above embodiment, and it goes without saying that various modifications can be made without departing from the gist of the invention. For example, the pneumatic stopper device 80 can be replaced with a double-acting air cylinder including a block provided with a cylinder.

[0157] Also, the pneumatic stopper device 80 can be replaced with a double-acting air cylinder or a single-acting air cylinder that includes a biasing member (eg, a coil spring) that biases the stopper 82 to the forward position.

[0158] The hydraulic clamper device 40 can be changed to a single-acting type instead of a double-acting type. Also, the hydraulic clamper device 40 can be replaced with a pneumatic clamper device or an electric clamper device, provided that it is driven by a drive source different from that of the pneumatic stopper device 80.

[0159] The mold opening / closing cylinder 25 of the molding machine 1A can be replaced with the mold opening / closing mechanism 110 of the molding machine 1B or other similar mechanisms. The number of hydraulic clamper devices 40 can be increased or decreased as appropriate. The mold clamping device of the injection molding machine may be one in which a rotary table capable of mounting multiple molds is provided on the movable platen 21, and multi-color molding is performed using multiple injection devices. Furthermore, the mold clamping device of the injection molding machine may be used to perform various moldings such as insert molding, foam molding, reinforced fiber resin molding, and mold slide molding.

[0160] Furthermore, the present invention can also be applied to clamping devices other than injection molding machines, in which a mold attached to a fixed platen and a mold attached to a movable platen are opened, molding material is supplied to the mold from an extruder or another material supply device, and then the mold is clamped to perform compression molding. [Explanation of symbols]

[0161] Reference Signs List 1A, 1B... injection molding machine (molding machine), 2... base, 3... injection unit, 4... mold clamping unit, 10... heating cylinder, 11... hopper, 12... drive unit, 14... nozzle, 15... notification unit, 21... mold mounting platen (movable platen), 22... mold mounting platen (fixed platen), 21a, 22a... mold mounting surface, 23... tie bar, 24... support plate, 25... hydraulic cylinder (mold opening / closing cylinder), 26... mold clamping cylinder, 27... ejector unit, 28... lifter, 30... mold, 31... mold (upper mold), 32... Die (lower die), 33... die body, 34... mounting plate, 35... die exchange cart, 36... fork, 37... fork drive unit, 40... hydraulic clamper device, 41... body unit, 42... clamper, 43... cylinder, 43a, 43b... oil chamber, 44... piston, 44a... head unit, 44b... rod unit, 45... pressing surface, 46a... forward port, 46b... backward port, 48... insertion hole, 50... clamper position detection unit, 51... protrusion, 52... limit switch, 52a... a actuator, 53...slit, 60...oil tank, 61...pump, 62...hydraulic control equipment group, 63...check valve, 64...pressure control valve, 65...directional change valve, 66...pressure switch, 70...control device, 71...controller, 72...input interface, 73...output interface, 80...pneumatic stopper device, 81...main body, 82...stopper, 83...bracket, 84...air cylinder, 85...cylinder tube, 85a, 85b...air chamber, 86...piston ton, 86a...head portion, 86b...rod portion, 87...holding surface, 88a...forward port, 88b...reverse port, 90...stopper position detection portion, 91...projection portion, 92, 93...proximity switch, 94...slit, 100...air compressor, 101...pneumatic control equipment group, 102...pressure control valve, 103...directional switching valve, 104...flow rate control valve, 105...check valve, 110...mold opening and closing mechanism, 111...servo motor, 112...screw shaft, 113...nut, P...center

Claims

1. a first mold mounting platen and a second mold mounting platen disposed opposite each other and relatively moved in a direction in which the first mold mounting platen approaches the second mold mounting platen and a direction in which the second mold mounting platen moves away from the first mold mounting platen; a first mechanical clamper capable of fixing a first mold to the first mold mounting platen; a second mechanical clamper capable of fixing a second mold to the second mold mounting platen; a stopper capable of holding the first mold relative to the first mold mounting platen, The first mechanical clamper, the second mechanical clamper and the stopper are driven by separate driving sources independent of each other.

2. The mold clamping device according to claim 1, the first mechanical clamper and the second mechanical clamper are hydraulically driven, The stopper is driven by air pressure.

3. The mold clamping device according to claim 1, The stopper includes a retention surface; When the first mold is fixed by the first mechanical clamper, at least the holding surface of the stopper is separated from the first mold, A mold clamping device in which, when the first mold is not fixed by the first mechanical clamper, at least the holding surface of the stopper abuts against the first mold to hold the first mold.

4. The mold clamping device according to claim 1, A plurality of the stoppers are provided, A mold clamping device, wherein the plurality of stoppers include a pair of the stoppers that are offset from each other with respect to the center of the first mold.

5. The mold clamping device according to claim 1, the first mechanical clamper is reciprocable between a forward position at which the first die is fixed and a backward position at which the first mechanical clamper is farther from the first die than the forward position; the second mechanical clamper is reciprocable between a forward position at which the second die is fixed and a backward position at which the second mechanical clamper is farther from the second die than the forward position; the stopper is reciprocable between an advanced position where the stopper holds the first die and a retracted position where the stopper is farther away from the first die than the advanced position; a clamper position detection unit that detects positions of the first mechanical clamper and the second mechanical clamper; and a stopper position detection unit that detects the position of the stopper.

6. The mold clamping device according to claim 1, the first mold mounting platen is disposed above the second mold mounting platen in a vertical direction; the first mechanical clamper fixes the first mold to a mold mounting surface of the first mold mounting platen that faces the second mold mounting platen in a vertical direction; The stopper is a clamping device that holds the first mold from a vertically lower side of the first mold.

7. a first mold mounting platen and a second mold mounting platen that are disposed opposite each other and are relatively moved in a direction in which they approach each other and in a direction in which they move away from each other; a first mechanical clamper capable of fixing a first mold to the first mold mounting platen; a second mechanical clamper capable of fixing a second mold to the second mold mounting platen; a stopper capable of holding the first mold relative to the first mold mounting platen, the first mechanical clamper is reciprocable between a forward position at which the first die is fixed and a backward position at which the first mechanical clamper is farther from the first die than the forward position; the second mechanical clamper is reciprocable between a forward position at which the second die is fixed and a backward position at which the second mechanical clamper is farther from the second die than the forward position; the stopper is reciprocable between an advanced position where the stopper holds the first die and a retracted position where the stopper is farther away from the first die than the advanced position; A method for controlling a mold clamping device, comprising: detecting movement of the first mechanical clamper and the second mechanical clamper to the forward position; and permitting relative movement of the first mold mounting platen and the second mold mounting platen when detecting movement of the stopper to the forward position.

8. The method for controlling a mold clamping device according to claim 7, the first mechanical clamper and the second mechanical clamper are hydraulically driven, A method for controlling a mold clamping device, comprising: detecting movement of the first mechanical clamper and the second mechanical clamper to the forward position; detecting that a pressure of hydraulic oil supplied to the first mechanical clamper and the second mechanical clamper has exceeded a threshold; and detecting movement of the stopper to the forward position, permitting relative movement of the first mold mounting platen and the second mold mounting platen.

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