Injection unit and injection molding machine

Abstract

To provide a heater for heating cylinder which can conduct cooling properly.SOLUTION: A heater for heating a cylinder (30) is composed of a plurality of infrared heaters (35) arranged surrounding a heating cylinder (19) in a manner of non-contacting with the heating cylinder (19), a heat insulator (34) provided outside of the infrared heaters (35), and a cover (32) covering the heat insulator (34). The cover (32) is provided with two or more of openings (39, 40) and open-close means (42) for opening and closing the opening (40).SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a heating cylinder heater for heating a heating cylinder of an injection molding machine, an injection device equipped with the heating cylinder heater, and an injection molding machine. [Background technology]

[0002] An injection molding machine consists of an injection unit and a mold clamping unit. The injection unit has a heating cylinder and a screw placed inside the heating cylinder. A band heater is attached to the heating cylinder. The heating cylinder is heated by the band heater, the injection material is fed, and the screw rotates. The heat from the band heater and the shear heat generated by the rotation of the screw melt the injection material and allow it to be measured. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 59-184623

[0004] Patent Document 1 describes a heating cylinder heater equipped with an infrared heater. The heating cylinder heater described in Patent Document 1 is composed of multiple infrared rays provided on the outside of the heating cylinder in a non-contact manner and a heat insulating material provided on the outside of these infrared heaters. When an electric current is supplied to the infrared heater, the heating cylinder is heated by the infrared rays. Summary of the Invention [Problem to be solved by the invention]

[0005] Both the band heater and the heating cylinder heater described in Patent Document 1 are excellent in that they can heat the heating cylinder appropriately. However, there are also issues that need to be resolved. The heating cylinder generates heat due to shear forces generated in the injected material when the screw rotates, and depending on the position, the temperature may become higher than the target temperature. The temperature is particularly likely to rise at the middle position of the heating cylinder. For example, if a band heater is provided on the heating cylinder, cold air can be blown onto the band heater from the outside, but the insulating material provided on the band heater prevents efficient cooling. The heating cylinder heater described in Patent Document 1 has the problem of lacking a means for cooling.

[0006] The present disclosure provides a cylinder heater that can provide appropriate cooling.

[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] The present disclosure provides: The present invention relates to an injection device including a heating cylinder and a screw provided in the heating cylinder. The heating cylinder is divided into a plurality of zones, and predetermined heating cylinder heaters are provided corresponding to one or more specific zones, while non-opening heating cylinder heaters are provided in the other zones. Cylinder heater teeth, The heating cylinder is surrounded by a plurality of infrared heaters arranged in a non-contact manner, and a heat insulating material is provided on the outside of the infrared heaters. The cover has two or more openings, and opening / closing means are provided in some or all of the openings to open and close the openings. [Effects of the Invention]

[0009] The present disclosure can efficiently cool the heating cylinder. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a front view showing an injection molding machine according to an embodiment of the present invention; [Figure 2] 1 is a front view showing an injection device equipped with a heating cylinder heater according to an embodiment of the present invention. [Figure 3] 1 is a side cross-sectional view showing an injection device equipped with a heating cylinder heater according to an embodiment of the present invention. [Figure 4] 1 is a side cross-sectional view showing an injection device equipped with a heating cylinder heater according to an embodiment of the present invention. [Figure 5A] FIG. 10 is a side cross-sectional view showing an injection device equipped with a heating cylinder heater according to a second embodiment of the present invention. [Figure 5B] FIG. 10 is a side cross-sectional view showing an injection device equipped with a heating cylinder heater according to a second embodiment of the present invention. [Figure 5C] FIG. 10 is a side cross-sectional view showing an injection device equipped with a heating cylinder heater according to a third embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0011] Specific embodiments will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments. For clarity of explanation, the following description and drawings have been simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and duplicate explanations are omitted as necessary. Furthermore, hatching has been omitted in some areas to avoid cluttering the drawings.

[0012] <Injection molding machine> As shown in Fig. 1, an injection molding machine 1 according to this embodiment includes a mold clamping unit 2, an injection unit 3, etc. The injection molding machine 1 includes a controller, i.e., a control device 4, and the mold clamping unit 2, injection unit 3, etc. are controlled by the control device 4. A heating cylinder heater 30, which will be described later, is also controlled by the control device 4. In Fig. 1, the heating cylinder heater 30 is indicated by a dotted line.

[0013] <Mold clamping device> The mold clamping unit 2 includes a fixed platen 7 fixed to a bed B, a movable platen 8 slidably provided on the bed B, and a mold clamping housing 9. The fixed platen 7 and the mold clamping housing 9 are connected by a plurality of tie bars 11, 11, ..., and the movable platen 8 is slidably provided between the fixed platen 7 and the mold clamping housing 9. A mold clamping mechanism, that is, a toggle mechanism 13 in this embodiment, is provided between the mold clamping housing 9 and the movable platen 8. A fixed-side mold 15 and a movable-side mold 16 are provided on the fixed platen 7 and the movable platen 8, respectively. Therefore, when the toggle mechanism 13 is driven, the molds 15, 16 are opened and closed.

[0014] <Injection device> The injection device 3 includes a heating cylinder 19, a screw 20 provided in the heating cylinder 19, and a screw drive device 22. The heating cylinder 19 is supported by the screw drive device 22, and the screw 20 is driven in the rotational direction and the axial direction by the screw drive device 22. The heating cylinder 19 is provided with a hopper 23 and an injection nozzle 24.

[0015] <Cylinder heater> The heating cylinder heater 30 according to this embodiment will now be described. As shown in FIG. 2, the heating cylinder heater 30 is provided on the heating cylinder 19, and in this embodiment, it is composed of four heaters. Specifically, it is composed of a first heating cylinder heater 30H1 close to the hopper 23, a second heating cylinder heater 30H2 downstream of the first heating cylinder heater, a third heating cylinder heater 30H3 downstream of the first heating cylinder heater, and a fourth heating cylinder heater 30H4 downstream of the first heating cylinder heater and close to the injection nozzle 24. The second and third heating cylinder heaters 30H2 and 30H3 have the same structure, so the third heating cylinder heater 30H3 will be described first.

[0016] As shown in FIGS. 2 and 3 , the third heating cylinder heater 30H3 includes a cylindrical cover 32, a heat insulating material 34 provided inside the cover 32, and multiple infrared heaters 35, 35, ... arranged inside the heat insulating material 34. The infrared heaters 35, 35, ... are arranged outside the heating cylinder 19 without contacting the heating cylinder 19. Therefore, when the infrared heaters 35, 35, ... are energized, they emit infrared rays to heat the heating cylinder 19. In this embodiment, a reflector 36 is provided on the inner surface of the heat insulating material 34. While the reflector 36 is not necessarily an essential component, it reflects infrared rays and can efficiently heat the heating cylinder 19. Note that instead of the reflector 36, a metal film may be formed on the inner surface of the heat insulating material 34 by vapor deposition or the like.

[0017] In this embodiment, cover 32 has one opening 39 at its bottom and one opening 40 at its top. These openings 39, 40 penetrate insulation 34 and communicate with the space surrounded by the inside of insulation 34 and the outer circumferential surface of heating cylinder 19. Of these openings 39, 40, lower opening 39 is always open, while upper opening 40 is provided with opening / closing means 42 for opening and closing opening 40. Opening / closing means 42 is composed of a lid 43 that closes opening 40, a cylinder unit 44 that drives lid 43, and a bracket 45 that supports cylinder unit 44. Cylinder unit 44 is driven by control device 4, and when driven, lid 43 opens and closes opening 40. These openings 39, 40 and opening / closing means 42 serve as cooling means for cooling heating cylinder 19.

[0018] In this embodiment, as shown in Figure 3, the cover 32 has a split structure consisting of an upper half and a lower half, which are connected by a hinge 47. Therefore, when a fastener (not shown) is released, the lower half of the cover 32 rotates around the hinge 47 and opens as shown by the dotted line at 49. This allows the third heating cylinder heater 30H3 to be removed from the heating cylinder 19.

[0019] As described above, the second heating cylinder heater 30H2 has a similar configuration to the third heating cylinder heater 30H3, and therefore a detailed description thereof will be omitted. The first and fourth heating cylinder heaters 30H1 and 30H4 have a similar configuration to the third heating cylinder heater 30H3, but with some differences. Specifically, they lack the openings 39 and 40 and the opening / closing mechanism 42. That is, the first and fourth heating cylinder heaters 30H1 and 30H4 lack cooling mechanisms for cooling the heating cylinder 19. The reason the first heating cylinder heater 30H1 does not have a cooling mechanism is that the portion of the heating cylinder 19 closest to the hopper 23 is relatively easily cooled by heat transfer to the screw drive device 22. The reason the fourth heating cylinder heater 30H4 does not have a cooling mechanism is that the tip of the heating cylinder 19 is exposed and relatively easily cooled.

[0020] <effect> The operation of the heating cylinder heater 30 according to this embodiment will now be described. When the injection molding machine 1 (see FIG. 1) starts operation, power is supplied to the heating cylinder heater 30 under the control of the control device 4. That is, the infrared heaters 35, 35, ... of the first to fourth heating cylinder heaters 30H1, 30H2, ... (see FIGS. 2 and 3) are energized. Infrared rays are emitted from the infrared heaters 35, 35, ... to heat the heating cylinder 19. A temperature sensor (not shown) is embedded in the heating cylinder 19, and the control device 4 controls it to reach a target temperature. The mold clamping device 2 is driven to clamp the molds 15, 16. An injection material is supplied from the hopper 23, and the screw 20 is rotated. The injection material is then melted and sent forward to the heating cylinder 19, i.e., metered. When the screw 20 is driven axially, the injection material is injected into the molds 15, 16, and a molded product is formed.

[0021] The heating cylinder 19 also generates heat due to shear forces acting on the injection material as the screw 20 rotates. As the molding cycle is repeated, this heat generation can cause the heating cylinder 19 to exceed the target temperature depending on its position. The control device 4 drives the opening / closing mechanism 42 (see Figure 3) of the heating cylinder heater 30. Specifically, the cylinder unit 44 is driven to open the lid 43. This opens the upper opening 40, as shown in Figure 4. The internal space surrounded by the outer circumferential surface of the heating cylinder 19 and the inner circumferential surface of the thermal insulation material 34 is filled with hot air. Because hot air has a low specific gravity, it flows out through the upper opening 40, while cooler air simultaneously flows in through the lower opening 39. This convection quickly replaces the air in the internal space, cooling the heating cylinder 19. Once the heating cylinder 19 reaches the target temperature, the cylinder unit 44 is driven to close the lid 43.

[0022] The heating cylinder heater 30 according to this embodiment has openings 39 and 40 in the cover 32, and an opening / closing mechanism 42 is provided at the upper opening 40, so that the heating cylinder 19 can be cooled quickly. Therefore, the heating cylinder 19 can be cooled quickly and efficiently even when changing the type of injection material, i.e., changing resin or color. Furthermore, cooling can be performed efficiently by utilizing air convection, which saves energy.

[0023] <Second embodiment> This embodiment can be modified in various ways. FIG. 5A shows a portion of a heating cylinder heater 30A according to a second embodiment. In this embodiment, the opening / closing means 42A for the opening 40 is modified. The opening / closing means 42A is composed of a valve element 51 that slides laterally, a rack 52 that drives the valve element 51, and a pinion 53. The pinion 53 is driven by a motor (not shown), and rotation of the pinion 53 causes the valve element 51 to slide. In this embodiment, the valve element 51 is designed to adjust the opening of the opening 40. Therefore, the strength of cooling can be controlled by increasing the opening when rapid cooling is desired and decreasing the opening when gradual cooling is desired.

[0024] 5B shows a portion of a heating cylinder heater 30B according to a third embodiment. In this embodiment, too, the opening / closing means 42B for the opening portion 40 is modified. The opening / closing means 42B is composed of a plurality of rotatably mounted shutters 56, 56, ..., a drive rod 58 that rotates the shutters 56, 56, ..., and a cylinder unit 59 that drives the drive rod 58. By controlling the cylinder unit 59, the amount of drive of the drive rod 58 can be adjusted, and the amount of rotation of the shutters 56, 56, ... can be adjusted. This allows the degree of opening of the opening portion 40 to be adjusted.

[0025] FIG. 5C shows a heating cylinder heater 30C according to a fourth embodiment. In this embodiment, the cover 32 has two upper openings 40, 40, which are located slightly below the top of the cover 32. Each of these openings 40, 40 is provided with an opening / closing mechanism 42, 42 similar to that of the heating cylinder heater 30 according to the first embodiment (see FIG. 3). The lower opening 39 is located slightly above the bottom of the cover 32 and is connected to a blower 61. In the heating cylinder heater 30C according to the fourth embodiment, only one of the opening / closing mechanisms 42, 42 may be driven to open or close one of the openings 40, 40, or both may be driven to open or close both openings 40. This allows the strength of cooling to be adjusted. To further increase the cooling strength, compressed air is forcibly supplied by the blower 61. Compressed air can also be supplied by other means, such as a compressed air source, instead of the blower 61.

[0026] <Other variations> This embodiment can be modified in many other ways. For example, in the first embodiment, the second heating cylinder heater 30H2 and the third heating cylinder heater 30H3 have been described as having the lower openings 39, 39 in the covers 32, 32 always open. However, opening and closing means may be provided for these openings 39, 39. The opening and closing means may be driven to open the openings 39, 39 when cooling is required.

[0027] Other variations are possible. While the heating cylinder heater 30 has been described as consisting of first to fourth heating cylinder heaters 30H1, 30H2, ..., it may be composed of three or fewer, or five or more. Furthermore, in this embodiment, the first and fourth heating cylinder heaters 30H1, 30H4 have been described as not having openings 39, 40. However, the first and fourth heating cylinder heaters 30H1, 30H4 may also have openings 39, 40, and may be provided with opening / closing means 42 for opening 40.

[0028] The invention made by the inventor has been specifically described above based on the embodiments, but it goes without saying that the present invention is not limited to the above-described embodiments and various modifications are possible without departing from the spirit of the invention. The multiple examples described above can also be implemented in appropriate combinations. [Explanation of symbols]

[0029] 1 Injection molding machine 2 Mold clamping device 3 Injection unit 4 Control unit 7 Fixed plate 8 Movable plate 9. Clamping housing 11. Tie bar 13 Toggle mechanism 15 Fixed side mold 16 Movable mold 19 Heating cylinder 20 Screw 22 Screw drive device 23 Hopper 24 Injection nozzle 30 Heating cylinder heater 32 Cover 34 Insulation material 35 Infrared heater 36 Reflector 39 Opening 40 Opening 42 Opening and closing means 43 Lid 44 Cylinder unit 45 Bracket 47 Hinge 51 Valve body 52 Rack 53 Pinion

Claims

1. A heating cylinder; a screw provided in the heating cylinder, The heating cylinder is divided into a plurality of zones, and a predetermined heating cylinder heater is provided corresponding to one or more specific zones, and an openingless heating cylinder heater is provided in the other zones; The heating cylinder heater includes a plurality of infrared heaters arranged around the heating cylinder in a non-contact manner with the heating cylinder; a heat insulating material provided on the outside of the infrared heater; a cover covering the heat insulating material, The cover has two or more openings, and opening / closing means for opening and closing the openings is provided in some or all of the two or more openings, The injection device, wherein the opening-less heating cylinder heater is of a type in which the opening is not provided.

2. 2. The injection device according to claim 1, wherein the cover has one or more openings provided in a lower portion and one or more openings provided in an upper portion, and the opening / closing means is provided in at least one of the openings provided in the upper portion.

3. the injection device includes a control device; 3. The injection device according to claim 1, wherein the opening and closing means comprises an actuator, and the actuator is controlled by the control device.

4. 3. The injection device according to claim 1, wherein said opening / closing means adjusts the degree of opening of said opening.

5. 3. The injection device according to claim 1, wherein compressed air is supplied to the opening.

6. 3. The injection apparatus according to claim 1, wherein a plurality of said cylinder heaters are provided corresponding to the respective zones.

7. The injection device and the mold clamping device are provided. The injection device includes a heating cylinder and a screw provided in the heating cylinder, The heating cylinder is divided into a plurality of zones, and a predetermined heating cylinder heater is provided corresponding to one or more specific zones, and an openingless heating cylinder heater is provided in the other zones; The heating cylinder heater includes a plurality of infrared heaters arranged around the heating cylinder in a non-contact manner with the heating cylinder; a heat insulating material provided on the outside of the infrared heater; a cover covering the heat insulating material, The cover has two or more openings, and opening / closing means for opening and closing the openings is provided in some or all of the two or more openings, The aforementioned non-opening heating cylinder heater is of the type that does not have an opening, in this injection molding machine.

8. 8. The injection molding machine according to claim 7, wherein the cover has one or more openings provided in a lower portion and one or more openings provided in an upper portion, and at least one of the openings provided in the upper portion is provided with the opening / closing means.

9. the injection molding machine includes a control device; 9. The injection molding machine according to claim 7, wherein the opening and closing means comprises an actuator, and the actuator is controlled by the control device.

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