Injection molding machine

[0026] Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings. In addition, in the present embodiment, regarding the mold clamping device, the moving direction of the movable platen when closing the mold is set to the front, and the moving direction of the movable platen when opening the mold is set to the rear. The moving direction of the screw during injection is set to the front, and the moving direction of the screw during the measurement is set to the rear for description.

[0027] figure 1 It is a diagram showing the state when the mold clamping device in the injection molding machine according to the embodiment of the present invention closes the mold, figure 2 It is a figure which shows the state at the time of mold opening of the mold clamping apparatus in the injection molding machine of embodiment of this invention. In addition, in figure 1 and figure 2 In, the hatched parts represent the main section.

[0028] In the figure, 10 is a mold clamping device, Fr is a frame (support) of the injection molding machine, Gd is a guide that is movable relative to the frame Fr, and 11 is a guide that is placed on a guide or frame Fr not shown The fixed pressure plate is spaced apart from the fixed pressure plate 11 at a predetermined interval and a rear pressure plate 13 is arranged opposite to the fixed pressure plate 11, and 4 connecting rods 14 are erected between the fixed pressure plate 11 and the rear pressure plate 13 (only 4 connecting rods are shown in the figure) 2 of 14). In addition, the rear pressure plate 13 is fixed to the frame Fr.

[0029] A threaded portion (not shown) is formed on the tip portion (right end portion in the figure) of the connecting rod 14, and a nut n1 is screwed and fastened to the threaded portion, whereby the tip portion of the connecting rod 14 is fixed to the fixed pressure plate 11. The rear end of the connecting rod 14 is fixed to the rear pressure plate 13.

[0030] In addition, a movable pressing plate 12 is arranged along the connecting rod 14 to face the fixed pressing plate 11 and to move forward and backward in the mold opening and closing direction. For this reason, the movable pressure plate 12 is fixed to the guide Gd, and a guide hole (not shown) for allowing the connection rod 14 to penetrate is formed in the movable pressure plate 12 corresponding to the connecting rod 14. In addition, notches may be formed instead of the guide holes. In addition, the suction plate 22 described later is fixed to the guide Gd.

[0031] In addition, the fixed mold 15 is fixed on the fixed platen 11, and the movable mold 16 is fixed on the movable platen 12. As the movable platen 12 advances and retreats, the fixed mold 15 and the movable mold 16 are in contact and separated to perform mold closing, mold clamping, and Mold. In addition, as the mold clamping is performed, a cavity space not shown is formed between the fixed mold 15 and the movable mold 16, and the cavity space is filled with resin not shown, which is injected from the injection nozzle 18 of the injection device 17. In addition, the fixed mold 15 and the movable mold 16 constitute a mold device 19.

[0032] The suction plate 22 is fixed to the guide Gd in parallel with the movable pressure plate 12. Thereby, the suction plate 22 can advance and retreat more rearward than the rear pressure plate 13. The adsorption plate 22 may be formed of a magnetic material. For example, the suction plate 22 may be composed of an electromagnetic laminated steel plate formed by laminating thin plates made of ferromagnetic material. Alternatively, the adsorption plate 22 may be formed by casting.

[0033] The linear motor 28 is provided on the guide Gd in order to advance and retreat the movable platen 12. The linear motor 28 includes a stator 29 and a mover 31. The stator 29 is formed on the frame Fr so as to be parallel to the guide Gd and corresponding to the moving range of the movable platen 12. The mover 31 is formed on the lower end of the movable platen 12 and the stator 29 Opposite and cover a predetermined range.

[0034] The mover 31 includes an iron core 34 and a coil 35. In addition, the iron core 34 includes a plurality of magnetic pole teeth 33 protruding toward the stator 29 and formed at a predetermined pitch, and the coil 35 is wound around each magnetic pole tooth 33. In addition, the magnetic pole teeth 33 are formed to be parallel to each other in a direction perpendicular to the moving direction of the movable platen 12. In addition, the stator 29 includes an iron core (not shown) and a permanent magnet (not shown) formed by extending the iron core. The permanent magnet is formed by alternately receiving magnetic poles of the N pole and the S pole. When the linear motor 28 is driven by supplying a predetermined current to the coil 35, the mover 31 advances and retreats, and accordingly, the movable platen 12 advances and retreats through the guide Gd, and mold closing and mold opening can be performed.

[0035] In addition, in the present embodiment, the permanent magnet is arranged on the stator 29 and the coil 35 is arranged on the mover 31, but it is also possible to arrange the coil on the stator and arrange the permanent magnet on the mover. . At this time, the coil does not move with the drive of the linear motor 28, so wiring for supplying power to the coil can be easily performed.

[0036] In addition, the structure is not limited to the structure in which the movable pressure plate 12 and the suction plate 22 are fixed to the guide Gd, and a structure in which the mover 31 of the linear motor 28 is provided on the movable pressure plate 12 or the suction plate 22 may be adopted. In addition, the mold opening and closing mechanism is not limited to the linear motor 28, and may be a hydraulic type or an electric type.

[0037] When the movable platen 12 advances and the movable mold 16 and the fixed mold 15 abut, the mold is closed, and then the mold is closed. An electromagnet unit 37 for mold clamping is arranged between the rear pressure plate 13 and the suction plate 22. In addition, a center rod 39 that extends through the rear pressure plate 13 and the suction plate 22 and connects the movable pressure plate 12 and the suction plate 22 is disposed so as to advance and retreat. The center rod 39 advances and retreats the suction plate 22 in conjunction with the advance and retreat of the movable platen 12 during mold closing and mold opening, and transmits the suction force generated by the electromagnet unit 37 to the movable platen 12 when the mold is closed.

[0038] In addition, the mold clamping device 10 is composed of the fixed pressing plate 11, the movable pressing plate 12, the rear pressing plate 13, the suction plate 22, the linear motor 28, the electromagnet unit 37, the center rod 39, and the like.

[0039] The electromagnet unit 37 includes an electromagnet 49 formed on the side of the rear pressure plate 13 and a suction portion 51 formed on the side of the suction plate 22. In addition, in a predetermined portion of the rear end surface of the rear pressure plate 13, in this embodiment, a coil groove 45 is formed around the center rod 39. In addition, the coil 48 is wound around the iron core 46 in the coil slot 45. In addition, the rear pressing plate 13 may be composed of an integral structure of a casting, or may be composed of an electromagnetic laminated steel plate formed by laminating thin plates composed of a ferromagnetic material.

[0040] In addition, in this embodiment, the electromagnet 49 may be formed separately from the back pressure plate 13 and the suction part 51 may be formed separately from the suction plate 22, or the electromagnet may be formed as a part of the back pressure plate 13 and the suction part may be used as the suction plate 22 Part of the formation. In addition, the electromagnet and the suction unit may be arranged in reverse. For example, an electromagnet 49 may be provided on the side of the suction plate 22 and a suction portion may be provided on the side of the rear pressure plate 13.

[0041] In the electromagnet unit 37, when a current is supplied to the coil 48, the electromagnet 49 is driven to attract the suction part 51, and a mold clamping force can be generated.

[0042] The center rod 39 is arranged so as to be connected to the suction plate 22 at the rear end and connected to the movable pressure plate 12 at the front end. Therefore, the center rod 39 advances with the movable platen 12 and advances the suction plate 22 when the mold is closed, and retreats with the movable platen 12 and the suction plate 22 when the mold is opened. For this reason, a hole 41 for penetrating the center rod 39 is formed in the center of the rear pressure plate 13, and a bearing member Br1 such as a bush that slidably supports the center rod 39 is disposed facing the opening at the front end of the hole 41.

[0043] The drive of the linear motor 28 and the electromagnet 49 of the mold clamping device 10 is controlled by the control unit 60. The control unit 60 includes a CPU, a memory, and the like, and also includes a circuit for supplying current to the coil 35 of the linear motor 28 or the coil 48 of the electromagnet 49 based on the result calculated by the CPU. A load detector 55 is also connected to the control unit 60. The load detector 55 is provided at a predetermined position of at least one connecting rod 14 in the clamping device 10 (a predetermined position between the fixed pressure plate 11 and the rear pressure plate 13 ), and detects the load applied to the connecting rod 14. The figure shows an example in which the load detector 55 is installed on two upper and lower connecting rods 14. The load detector 55 is composed of, for example, a sensor that detects the amount of extension of the connecting rod 14. The load detected by the load detector 55 is sent to the control unit 60. In addition, for convenience figure 2 The control unit 60 is omitted in the.

[0044] Next, the operation of the mold clamping device 10 will be described.

[0045] The mold closing process is controlled by the mold opening and closing processing unit 61 of the control unit 60. in figure 2 In the state (the state when the mold is opened), the mold opening and closing processing unit 61 supplies current to the coil 35. Then, the linear motor 28 is driven, and the movable platen 12 moves forward as figure 1 As shown, the movable mold 16 and the fixed mold 15 abut against each other. At this time, a gap δ is formed between the rear pressing plate 13 and the suction plate 22, that is, between the electromagnet 49 and the suction portion 51. In addition, the force required to close the mold is very small compared to the clamping force.

[0046] Next, the mold clamping processing unit 62 of the control unit 60 controls the mold clamping process. The mold clamping processing unit 62 supplies electric current to the coil 48, and the attraction unit 51 is attracted by the attraction force of the electromagnet 49. Following this, the mold clamping force is transmitted to the movable platen 12 via the suction plate 22 and the center rod 39, thereby performing mold clamping. When the mold clamping force changes at the start of mold clamping, the mold clamping processing unit 62 controls so as to generate the target mold clamping force that should be obtained by the change, that is, the target mold clamping force in a stable state. The stable current value is supplied to the coil 48.

[0047] In addition, the clamping force is detected by the load detector 55. The detected mold clamping force is sent to the control unit 60, and the control unit 60 adjusts the current supplied to the coil 48 in order to make the mold clamping force a set value, and performs feedback control. During this period, the resin melted in the injection device 17 is ejected from the injection nozzle 18 and filled in the cavity space of the mold device 19.

[0048] When the resin in the cavity space is cooled and solidified, the mold opening and closing processing unit 61 controls the mold opening process. in figure 1 In the state of, the mold clamping processing unit 62 stops supplying current to the coil 48. Following this, the linear motor 28 is driven and the movable platen 12 retreats, such as figure 2 As shown, the movable mold 16 is placed in the backward limit position to open the mold.

[0049] Here, reference image 3 The following sections describe the characteristic structure of the present invention.

[0050] image 3 The multi-pole structure based on Example 1 is shown, and it is a top view of the rear pressure plate 13 in which the coil 48 is arrange|positioned viewed from the suction plate 22 side toward the mold clamping direction. Figure 4 Is along image 3 A cross-sectional view of the line A-A.

[0051] Such as Figure 4 As shown, a plurality of coils 48 are stacked and arranged in the coil slot 45. In addition, the stacking direction corresponds to the depth direction Y of the coil groove 45. Figure 4 In the illustrated example, four coils 48a, coils 48b, coils 48c, and coils 48d are provided. The coils 48a and 48b of the first group are stacked and arranged in the coil slot 45 on the inner circumference side, and the coils 48c and 48d of the second group are stacked and arranged in the coil slot 45 on the outer circumference side. Thereby, the electromagnet 49 with a plurality of poles is formed.

[0052] In addition, in the example shown in the figure, two coil slots 45 on the inner peripheral side and the outer peripheral side are formed, and each of the coil slots 45 is formed in a rectangular shape so as to surround a central portion 46 a that is a part of the iron core 46. An intermediate core portion 46b as a part of the core 46 is formed between the two coil slots 45 on the inner peripheral side and the outer peripheral side. In addition, the surfaces (side surfaces of the suction plate 22) of the central portion 46a, the outer peripheral portion 47a, and the intermediate core portion 46b may extend in the same plane to divide the gap surface. The coil groove 45 has a bottom surface that is only offset from the gap surface by its corresponding depth.

[0053] Figure 5 An example of an electrical circuit diagram for driving the electromagnet unit 37 based on the first embodiment is shown. Figure 5 An example in which four coils 48a, coil 48b, coil 48c, and coil 48d are connected in parallel with respect to one power supply is shown. At this time, it is preferable that the coil 48a and the coil 48b on the inner peripheral side are connected in series with each of the coil 48c and the coil 48d on the outer peripheral side. More preferably, the coil 48b and the coil 48d on the bottom side in the coil slot 45 are connected in series with each of the coil 48a and the coil 48c on the opening side in the coil slot 45. In the example shown in the figure, the coil 48a on the inner circumference side and the opening side in the coil groove 45 is connected in series with the coil 48d on the outer circumference side and the bottom side in the coil groove 45, and the bottom of the coil groove 45 is on the inner circumference side. The coil 48b on the side is connected in series with the coil 48c on the opening side in the coil slot 45 on the outer peripheral side. In addition, the coil 48a and the coil 48d, and the coil 48b and the coil 48c are connected in parallel with one power supply.

[0054] In this way, by connecting a plurality of coils 48a, coil 48b, coil 48c, and coil 48d in parallel with respect to the power supply instead of connecting in series, the voltage applied to coil 48a, coil 48b, coil 48c, and coil 48d can be increased, and the electromagnet unit can be increased. 37 responsiveness. In addition, from the same viewpoint, a power supply may be provided for each of the coil 48a, the coil 48b, the coil 48c, and the coil 48d. In addition, a power source may be provided separately for the group of the coil 48a and the coil 48d and the group of the coil 48b and the coil 48c.

[0055] Here, the coil resistance (resistance component of the coil) of the coil 48a, the coil 48b, the coil 48c, and the coil 48d depends on the total length of the coil 48a, the coil 48b, the coil 48c, and the coil 48d. Therefore, when the number of windings is the same, the coil 48a and the coil 48b on the inner circumference side have substantially the same coil resistance, the coil 48c and the coil 48d on the outer circumference side have substantially the same coil resistance as each other, and the coil 48c and the coil 48d on the outer circumference side have substantially the same coil resistance. The coil resistance becomes larger than the coil resistances of the coil 48a and the coil 48b on the inner circumference side. Therefore, by Figure 5 The coil 48a, the coil 48b, the coil 48c, and the coil 48d are connected as shown, and the coil resistance of the coil 48a and the coil 48d as a whole is substantially the same as the coil resistance of the coil 48b and the coil 48c as a whole. Thus, even when the coil 48a, the coil 48b, the coil 48c, and the coil 48d are connected in parallel, it is possible to alleviate the imbalance caused by the change in the coil resistance due to heat. In addition, the inductance of each of the coil 48a, the coil 48b, the coil 48c, and the coil 48d depends on the position (depth) in the coil slot 45 or the area enclosed by the coil. Therefore, by Figure 5 The illustrated method connects the coil 48a, the coil 48b, the coil 48c, and the coil 48d to alleviate the imbalance of the inductance between the coil 48a and the coil 48d and the coil 48b and the coil 48c.

[0056] In addition, Figure 3 to Figure 5 In the example shown, four coils 48a, coil 48b, coil 48c, and coil 48d form two poles (two phases), but the number of poles can be any number.

[0057] Image 6 It is a figure which shows the multipole structure based on another Example (Example 2), and is the top view which looked at the back pressure plate 13 in which the coil 48 was arrange|positioned from the suction plate 22 side toward a mold clamping direction. Figure 7 Is along Image 6 A cross-sectional view of the line B-B.

[0058] In the second embodiment, an electromagnet is provided on the rear pressing plate 13 to form 4 poles. Specifically, four iron cores 46e-46h are provided between the central part 47b and the outer peripheral part 47c forming the hole 41 through which the central rod 39 passes. The coil groove 45 is formed so as to surround each of the iron cores 46e-46h. A coil 48e-48h is wound around each iron core 46e-46h. In addition, due to Image 6 It is a simplified drawing, so the coils 48e-48h are shown in contact with each other, but the coils 48e-48h may also be spaced apart from each other.

[0059] In the second embodiment, as in the first embodiment described above, a plurality of coils are stacked and arranged in the coil slot 45. Specifically, such as Figure 7 As shown, the coil 48h includes 2 coils 48h 1 , Coil 48h 2 , 2 coils 48h 1 , Coil 48h 2 The stack is arranged in the coil slot 45. Similarly, the coil 48f includes 2 coils 48f 1 , Coil 48f 2 , 2 coils 48f 1 , Coil 48f 2 The stack is arranged in the coil slot 45. In addition, Figure 7 Here, only the group of the coil 48h and the coil 48f is shown, but the coil 48e and the coil 48g of other groups may be the same.

[0060] Figure 8 An example of an electrical circuit diagram for driving the electromagnet unit 37 according to the second embodiment is shown. Figure 8 In, and Figure 7 Correspondingly, only the group of the coil 48h and the coil 48f is shown, but the coil 48e and the coil 48g of other groups may be the same.

[0061] Figure 8 Represents 4 coils 48h 1 , Coil 48h 2 , Coil 48f 1 , Coil 48f 2 This is an example of parallel connection with respect to one power supply. At this time, it is preferable that the bottom coil 48h in the coil slot 45 2 , Coil 48f 2 Each and the coil 48f on the opening side in the coil slot 45 1 , Coil 48h 1 Each is connected in series. And, the coil 48h 2 And coil 48f 1 With coil 48h 1 And coil 48f 2 It is connected in parallel with respect to one power supply.

[0062] In this way, by connecting multiple coils in parallel with the power supply for 48h 1 , Coil 48h 2 , Coil 48f 1 , Coil 48f 2 , Instead of connecting in series, it can increase the 48h applied to the coil 1 , Coil 48h 2 , Coil 48f 1 , Coil 48f 2 The responsiveness of the electromagnet unit 37 can be improved. In addition, according to the same point of view, it can also be relative to each coil 48h 1 , Coil 48h 2 , Coil 48f 1 , Coil 48f 2 Set the power supply. In addition, it can also be relative to the coil 48h 2 And coil 48f 1 Group and coil 48h 1 And coil 48f 2 Set the power supply separately for each group.

[0063] In addition, by Figure 8 Connect the coil as shown for 48h 1 , Coil 48h 2 , Coil 48f 1 , Coil 48f 2 Between, as a coil 48h 2 And coil 48f 1 The overall coil resistance and inductance become the same as the coil 48h 1 And coil 48f 2 The overall coil resistance and inductance are approximately the same. Therefore, even if the coil 48h is connected in parallel 1 , Coil 48h 2 , Coil 48f 1 , Coil 48f 2 At this time, it is also possible to prevent the imbalance of inductance, and to alleviate the imbalance caused by the change of the coil resistance due to heat.

[0064] Picture 9 It is a figure which shows the unipolar structure based on another Example (Example 3), and is the top view which looked at the back pressure plate 13 in which the coil 48 was arrange|positioned from the suction plate 22 side toward a mold clamping direction. Picture 10 Is along Picture 9 A cross-sectional view of the line C-C.

[0065] In the third embodiment, the coil groove 45 is formed in a rectangular shape around the center iron core 46g. Also in the third embodiment, similar to the above-mentioned first embodiment, a plurality of coils are stacked and arranged in the coil slot 45. Specifically, such as Picture 9 As shown, the coil 48g includes 4 coils 48g 1 , Coil 48g 2 , Coil 48g 3 , Coil 48g 4 , 4 coils 48g 1 , Coil 48g 2 , Coil 48g 3 , Coil 48g 4 The stack is arranged in the coil slot 45.

[0066] Picture 11 An example of an electrical circuit diagram for driving the electromagnet unit 37 according to the third embodiment is shown.

[0067] Picture 11 Represents 4 coils 48g 1 , Coil 48g 2 , Coil 48g 3 , Coil 48g 4 This is an example of parallel connection with respect to one power supply. At this time, it is preferable that the bottom side coil 48g in the coil slot 45 1 With the coil 48g on the opening side in the coil slot 45 4 Connected in series, the second coil 48g from the bottom side in the coil slot 45 2 And 48g of the second coil from the opening side in the coil slot 45 3 Connected in series. And, the coil 48g 1 And coil 48g 4 , And coil 48g 2 And coil 48g 3 It is connected in parallel with respect to one power supply.

[0068] In this way, by connecting multiple coils 48g in parallel with respect to the power supply 1 , Coil 48g 2 , Coil 48g 3 , Coil 48g 4 Instead of connecting in series, it can increase the 48g applied to the coil 1 , Coil 48g 2 , Coil 48g 3 , Coil 48g 4 The responsiveness of the electromagnet unit 37 can be improved. In addition, from the same point of view, it is also possible to compare each coil 48g 1 , Coil 48g 2 , Coil 48g 3 , Coil 48g 4 Set the power supply. In addition, it can also be relative to the coil 48g 1 And coil 48g 4 Group with coil 48g 2 And coil 48g 3 Set the power supply separately for each group.

[0069] In addition, by Picture 11 Connect the coil 48g as shown 1 , Coil 48g 2 , Coil 48g 3 , Coil 48g 4 Between, as a coil 48g 1 And coil 48g 4 The overall coil resistance and inductance become the same as the coil 48g 2 And coil 48g 3 The overall coil resistance and inductance are approximately the same. Thus, even if the coil 48g is connected in parallel 1 , Coil 48g 2 , Coil 48g 3 , Coil 48g 4 At this time, it is also possible to prevent the imbalance of inductance, and to alleviate the imbalance caused by the change of the coil resistance due to heat.

[0070] In addition, Figure 9 to Figure 11 In the example shown in 4 coils 48g 1 , Coil 48g 2 , Coil 48g 3 , Coil 48g 4 The coils are stacked in the coil slot 45, but when there are 6 or 8, more coils may be stacked in the coil slot 45.

[0071] Next, the coil cooling mechanism applicable to each of the above-mentioned embodiments will be described.

[0072] Picture 12 It is a diagram showing an example of a coil cooling mechanism. Among them, such as Picture 12 As shown, as an example, a mechanism in which two coils 48 are stacked is provided. The coil cooling mechanism 90 is arranged in the coil slot 45. As a result, the plurality of coils 48 stacked in the coil groove 45 as described above can be effectively cooled. The coil cooling mechanism 90 may be, for example, a pipe through which a cooling fluid flows, or a plate in which the passage of the cooling fluid is formed. The cooling fluid can be water or oil.

[0073] More specifically, Picture 12 In the example shown in (A), the coil cooling mechanism 90 is arranged between the plurality of coils in the depth direction of the coil groove 45. Picture 12 In the example shown in (A), it is arranged between two coils 48. In addition, when three or more coils are laminated, the coil cooling mechanism 90 may be provided between each layer, or the coil cooling mechanism 90 may be provided between specific layers.

[0074] Picture 12 In the example shown in (B), the coil cooling mechanism 90 is arranged to cover the uppermost coil 48 on the opening side of the coil slot 45. In addition, Picture 12 (B) The example shown can be compared with Picture 12 The examples shown in (A) are combined. That is, the coil cooling mechanism 90 may be provided between the plurality of coils 48 in the depth direction of the coil groove 45 and the coil cooling mechanism 90 may be provided to cover the uppermost coil 48 on the opening side of the coil groove 45.

[0075] In addition, in the above embodiment, the “first fixed member” in the technical solution corresponds to the fixed pressure plate 11, and the “first movable member” in the technical solution corresponds to the movable pressure plate 12. In addition, the "second fixed member" in the technical solution corresponds to the rear pressure plate 13, and the "second movable member" in the technical solution corresponds to the suction plate 22.

[0076] Above, the preferred embodiments of the present invention have been described in detail, but the present invention is not limited to the above-mentioned embodiments, and various modifications and substitutions can be made to the above-mentioned embodiments without departing from the scope of the present invention.

[0077] For example, as described above, the electromagnet 49 may be provided on the suction plate 22 side, and the suction portion may be provided on the rear pressure plate 13 side. In this way, when the electromagnet 49 is provided on the suction plate 22 side, it is only necessary to realize the same coil stack structure as described above on the suction plate 22 side.

[0078] In addition, in the above, the mold clamping device 10 having a specific structure is exemplified, but as long as the mold clamping device 10 uses an electromagnet to perform mold clamping, it may have any structure.