Shut-off nozzle with needle valve, injection unit, and injection molding machine

Abstract

To provide a shut-off nozzle that causes a low manufacturing cost and has no risk of deflection of a needle valve.SOLUTION: There is provided a shut-off nozzle (22) in which a needle valve (27) is provided coaxially with an injection nozzle (25) in a flow path (37) of the injection nozzle (25). A guide ring (32) is provided in the flow path (37) of the injection nozzle (25) in the shut-off nozzle (22). The needle valve (27) has a cylindrical shaft (40). The guide ring (32) is configured to guide the needle valve (27) on the shaft (40).SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a shut-off nozzle in which a needle valve, which is provided coaxially with the injection nozzle in the flow path of the injection nozzle, moves back and forth to open and close an injection port, an injection device equipped with such a shut-off nozzle, and an injection molding machine. [Background technology]

[0002] A shut-off nozzle equipped with a needle valve is well known as a shut-off nozzle provided in an injection device. In some of these shut-off nozzles, the needle valve is driven obliquely relative to the injection nozzle, and in other shut-off nozzles, the needle valve is driven coaxially. The latter type of shut-off nozzle is configured as follows. In the injection nozzle, a flow path through which the injection material flows is provided coaxially with the injection nozzle. A needle valve is provided in this flow path. That is, the needle valve is provided coaxially with the injection nozzle. The needle valve is moved forward and backward by a predetermined drive mechanism provided at the rear end of the needle valve. When the needle valve is driven forward, its tip closes the tip of the injection nozzle.

[0003] However, depending on the injection device, it may be necessary to adopt a shut-off nozzle with a long injection nozzle, which inevitably requires a long needle valve. In that case, the needle valve becomes easily bent due to its own weight, making it difficult to open and close the injection port with high accuracy when driving the needle valve.

[0004] Patent Document 1 proposes a shut-off nozzle that solves the problem of needle valve bending. The shut-off nozzle described in this document is provided with a guide mechanism near the injection nozzle's injection outlet. Specifically, a number of protrusions, i.e., support vanes, are formed near the injection nozzle's injection outlet from the inner circumferential surface of the flow path toward the center. The needle valve is guided at its tip by the support vanes to move forward and backward. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2002-370256 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the shut-off nozzle described in Patent Document 1, the needle valve is guided at its tip, so that bending is prevented and the needle valve opens and closes the injection port with high precision. However, the flow path of the injection material must be machined into a complex shape to form the support vanes. In other words, there is a problem that the manufacturing cost of the injection nozzle is high and the shut-off nozzle is expensive.

[0007] The present disclosure provides a shut-off nozzle capable of suppressing bending of a needle valve while suppressing an increase in the cost required for machining, an injection device including such a shut-off nozzle, and an injection molding machine.

[0008] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0009] The present invention is directed to a shut-off nozzle in which a needle valve is provided coaxially with the injection nozzle in the flow passage of the injection nozzle, and a guide ring is provided in the flow passage of the injection nozzle. The needle valve has a cylindrical shaft portion. The guide ring is configured to guide the forward and backward movement of the needle valve on this shaft portion. Effect of the Invention

[0010] According to the present disclosure, it is possible to suppress bending of the needle valve while suppressing an increase in the cost required for machining the shut-off nozzle. [Brief description of the drawings]

[0011] [Figure 1] 1 is a front view showing an injection molding machine according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a front cross-sectional view showing a shut-off nozzle and a part of an injection device according to the present embodiment. [Diagram 3] FIG. 2 is a front view showing a guide ring according to the first embodiment of the present invention. [Figure 4] 1 is a front cross-sectional view showing a part of a shut-off nozzle equipped with a guide ring according to a first embodiment of the present invention. [Diagram 5] FIG. 1 is a front cross-sectional view showing a portion of a conventional shut-off nozzle. [Figure 6A] FIG. 11 is a front view showing a guide ring according to a second embodiment of the present invention. [Figure 6B] FIG. 11 is a front view showing a guide ring according to a third embodiment of the present invention. [Figure 6C] FIG. 11 is a front view showing a guide ring according to a fourth embodiment of the present invention. [Figure 6D] FIG. 13 is a front view showing a guide ring according to a fifth embodiment of the present invention. [Figure 7] 11 is a front cross-sectional view showing a part of a shut-off nozzle according to another embodiment of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Specific embodiments will be described in detail below with reference to the drawings. However, the present invention is not limited to the following embodiments. In order to clarify the description, the following description and drawings are appropriately simplified. In each drawing, the same elements are given the same reference numerals, and duplicated descriptions are omitted as necessary. In addition, hatching is omitted in some parts to avoid cluttering the drawings.

[0013] The present embodiment will be described. <Injection molding machine> An injection molding machine 1 according to this embodiment is configured as shown in Fig. 1. That is, the machine is roughly composed of a mold clamping device 2 that clamps a mold, and an injection device 3 that melts and injects an injection material.

[0014] <Mold clamping device> In this embodiment, the mold clamping device 2 includes a fixed platen 5 fixed on a bed B, a mold clamping housing 6 that slides on the bed B, and a movable platen 7 that similarly slides on the bed B. The fixed platen 5 and the mold clamping housing 6 are connected by a plurality of, for example, four tie bars 9, 9, .... The movable platen 7 is slidable between the fixed platen 5 and the mold clamping housing 6. A mold clamping mechanism 11 is provided between the mold clamping housing 6 and the movable platen 7. The mold clamping mechanism 11 may be a direct pressure type mold clamping mechanism, that is, a mold clamping cylinder. However, in this embodiment, it is configured as a toggle mechanism. The fixed platen 5 and the movable platen 7 are provided with molds 13 and 14, respectively, and when the mold clamping mechanism 11 is driven, the molds 13 and 14 are opened and closed.

[0015] <Injection device> The injection device 3 is mounted on a base 15 and comprises a heating cylinder 16, a screw 17 inserted in the heating cylinder 16, and a screw drive device 18 for driving the screw 17. A hopper 20 is provided near the rear end of the heating cylinder 16, through which the injection material is supplied. A shut-off nozzle 22 according to the present embodiment, which will be described next, is provided at the tip of the heating cylinder 16.

[0016] <Shut-off nozzle> The shut-off nozzle 22 according to this embodiment is provided on the heating cylinder 16, as shown in Fig. 2. To explain in more detail, an adapter 16a is provided on the tip of the heating cylinder 16, and this adapter 16a is provided with the shut-off nozzle 22. The shut-off nozzle 22 includes a nozzle base 24 provided on the adapter 16a, an injection nozzle 25 provided on the tip of the nozzle base 24, and a needle valve 27 provided within the injection nozzle 25.

[0017] The injection nozzle 25 is composed of a nozzle adapter 29 provided on the nozzle base 24 and a nozzle tip 30 provided on the tip of the nozzle adapter 29. In this embodiment, the nozzle adapter 29 has a mounting hole 29a bored in the axial direction at its tip, and a female thread is formed therein. Meanwhile, the nozzle tip 30 has a male thread formed on its outer circumferential surface 30a, which is screwed into the mounting hole 29a. A guide ring 32 according to this embodiment, which will be described in detail later, is provided in the mounting hole 29a of the nozzle adapter 29, and the guide ring 32 is fastened by the nozzle tip 30. In other words, the guide ring 32 is held between the nozzle adapter 29 and the nozzle tip 30.

[0018] The flow path through which the injection material flows is configured as follows. First, a nozzle base inner flow path 34 that communicates with the bore of the heating cylinder 16 is formed inside the nozzle base 24. A support part 35 that supports the needle valve 27 is formed in the downstream part of the nozzle base 24. The support part 35 has a so-called torpedo shape, and is formed in the nozzle base inner flow path 34 at its downstream part. Therefore, the nozzle base inner flow path 34 is formed so as to surround the outer circumferential surface of the support part 35 in the vicinity of the support part 35.

[0019] A flow path that communicates with the nozzle base internal flow path 34, i.e., an injection nozzle internal flow path 37, is formed in the injection nozzle 25. The injection nozzle internal flow path 37 is formed to have the same diameter in the nozzle adapter 29 and the nozzle tip 30, but is reduced in diameter at the tip of the nozzle tip 30 to form an injection port 38.

[0020] The needle valve 27 is provided coaxially with the injection nozzle 25 in the injection nozzle inner flow path 37, and its rear end is provided in the support part 35. The needle valve 27 has a cylindrical shaft part 40, and the needle valve 27 is supported by the guide ring 32 at this shaft part 40.

[0021] The shut-off nozzle 22 according to this embodiment is provided with a piston cylinder unit 42 and a lever mechanism 43 as a drive mechanism for driving the needle valve 27. The rear end of the needle valve 27 is connected to the lever mechanism 43. When the piston cylinder unit 42 is driven, the lever mechanism 43 rotates, causing the needle valve 27 to move forward and backward.

[0022] <Guide ring> A guide ring 32A according to the first embodiment will be described. The guide ring 32A is made of a disk-shaped metal plate, as shown in a front view in Fig. 3. A guide hole 45 into which the needle valve 27 (see Fig. 2) is inserted is formed in the axis of the guide ring 32A. The diameter of the guide hole 45 is slightly larger than the outer diameter of the shaft portion 40 of the needle valve 27. Therefore, the needle valve 27 is allowed to slide smoothly along the guide hole 45 at the shaft portion 40.

[0023] The guide ring 32A has a plurality of holes 46, 46, ... formed around the guide hole 45. The plurality of holes 46, 46, ... are arranged at equal intervals on an imaginary circle C centered on the axis of the guide ring 32A. The plurality of holes 46, 46, ... are for allowing the injection material to flow. Note that the plurality of holes 46, 46, ... are preferably arranged at equal intervals on the imaginary circle C, but do not necessarily have to be arranged at equal intervals.

[0024] The guide ring 32A according to the present embodiment can be manufactured simply by drilling the guide hole 45 and the multiple holes 46, 46, ... in the disk-shaped metal plate. In other words, it can be manufactured by performing a hole drilling process on the metal plate. Therefore, it has the characteristic that an increase in manufacturing costs can be suppressed.

[0025] 4 shows a part of the shut-off nozzle 22 provided with the guide ring 32A according to the first embodiment. The needle valve 27 has its shaft portion 40 inserted into the guide hole 45 of the guide ring 32A. When the needle valve 27 moves forward or backward, the shaft portion 40 is guided by the guide ring 32A. Therefore, the needle valve 27 is not easily bent even if it is long. Since the needle valve 27 is not easily bent, the tip portion of the needle valve 27 can open and close the injection hole 38 with high accuracy.

[0026] <Conventional shut-off nozzle> A comparison with a conventional shut-off nozzle will be made. FIG. 5 shows a part of a conventional shut-off nozzle 70. In this shut-off nozzle 70, the needle valve 71 is processed into a special shape. That is, a vane portion 74 is formed at a predetermined position of the shaft portion 73. This vane portion 74 is designed to slide smoothly with respect to the flow path 76 of the injection nozzle 75. Therefore, even if the needle valve 71 is long, the needle valve 71 moves forward and backward without bending. However, providing the vane portion 74 to the needle valve 71 requires complicated processing, and the manufacturing cost is high. The guide ring 32A (see FIG. 3) according to this embodiment is excellent because it can be manufactured at low cost as described above.

[0027] <Guide ring according to the second embodiment> The guide ring 32 can be modified in various ways. FIG. 6A shows a guide ring 32B according to a second embodiment. The guide ring 32B has a plurality of small-diameter holes 46', 46', .... These small-diameter holes 46', 46', ... are arranged at equal intervals on three imaginary circles C1, C2, C3 of different diameters centered on the axis of the guide ring 32B. That is, some of the holes 46', 46', ... are arranged on the imaginary circle C1 of the smallest diameter near the guide hole 45, other parts are arranged on the imaginary circle C2 of a larger diameter than the imaginary circle C1, and the remaining parts are arranged on the imaginary circle C3 of the largest diameter, and are evenly arranged in the circumferential direction. These small-diameter holes 46, 46, ... are for the injection material to flow and also have a filter function to prevent the solid injection material from flowing out.

[0028] The small holes 46', 46', ... are preferably arranged at equal intervals on the three imaginary circles C1, C2, C3, but they do not necessarily have to be arranged at equal intervals. Also, in this embodiment, the small holes 46', 46', ... are arranged on the three imaginary circles C1, C2, C3 with different diameters, but they may be arranged on two or four or more imaginary circles.

[0029] <Guide ring according to the third embodiment> 6B shows a guide ring 32C according to a third embodiment. The shape of a hole 46'' formed in the guide ring 32C according to the third embodiment is a curved elongated hole with four rounded corners in an axial cross-sectional view. The number of holes 46'' is not limited to four.

[0030] <Guide ring according to the fourth embodiment> FIG. 6C shows a guide ring 32D according to a fourth embodiment. A hole 46'' formed in the guide ring 32D according to the fourth embodiment has a shape obtained by dividing a doughnut shape into a predetermined number of parts in an axial cross-sectional view. Note that in FIG. 6C, the number of divisions of the doughnut shape in the hole 46'' is four, but the number of divisions is not limited to four.

[0031] <Guide ring according to the fifth embodiment> FIG. 6D shows a guide ring 32E according to a fifth embodiment. In the guide ring 32E according to this embodiment, a guide portion 48 protrudes from a part of the inner peripheral surface of the ring-shaped portion toward the center in the radial direction. The guide portion 48 has a substantially triangular shape in a cross section perpendicular to the axial direction, and its tip portion 49 is formed in an arc shape. The needle valve 27 shown by the two-dot chain line in FIG. 6D is supported by this tip portion 49 and is guided smoothly without bending. In this embodiment, the area of ​​the cutout portion is large, so that the injected material flows smoothly.

[0032] <Shut-off nozzle according to other embodiments> In all of the embodiments described above, the guide rings 32A, 32B, ... are fixed to the injection nozzle 25 (see Figures 2 and 4), and the needle valve 27 is configured to slide at its shaft portion 40 relative to the guide rings 32A, 32B, ....

[0033] 7 shows a shut-off nozzle 22' different from these embodiments. That is, in this embodiment, the diameter of the guide hole 45' of the guide ring 32F is equal to or slightly smaller than the diameter of the shaft portion 40 of the needle valve 27. The guide ring 32E is tightly fitted to the shaft portion 40 of the needle valve 27. Therefore, when the needle valve 27 is moved forward or backward, the guide ring 32F also moves forward or backward together with the needle valve 27, and the guide ring 32F slides relative to the injection nozzle inner flow path 37 of the injection nozzle 25. The needle valve 27 is also prevented from bending in the shut-off nozzle 22' according to this embodiment.

[0034] Although the invention made by the present inventor has been specifically described above based on the embodiment, it goes without saying that the present invention is not limited to the embodiment already described, and various modifications are possible without departing from the gist of the invention. The above-described examples may be implemented in appropriate combination. [Explanation of symbols]

[0035] 1 Injection molding machine 2 Mold clamping device 3 Injection device 5 Fixed plate 6 Clamping housing 7 Movable platen 9 Tie bar 11 Clamping mechanism 13 Mold 14 Mold 15 Base 16 Heating cylinder 17 Screw 18 Screw drive unit 20 Hopper 22 Shut-off nozzle 24 nozzle base 25 injection nozzle 27 Needle valve 29 Nozzle adapter 29a Mounting hole 30 Nozzle tip 30a Outer periphery 32 Guide ring 34 nozzle base inner flow passage 35 support portion 37 Injection nozzle internal flow path 38 Injection outlet 40 shaft portion 42 piston cylinder unit 43 Lever mechanism 45 Guide hole 46 Hole 48 Guide part 49 Tip part

Claims

1. an injection nozzle having a flow path formed therein; a needle valve provided in the flow passage coaxially with the injection nozzle and driven by a drive mechanism to be moved back and forth in the axial direction; A guide ring provided in the flow path, The needle valve has a cylindrical stem, the flow passage is formed in the injection nozzle with a uniform diameter over a predetermined length, and in the section in which the flow passage is formed with the uniform diameter, the shaft portion is provided coaxially with the injection nozzle and with a predetermined gap between the shaft portion and the bore of the flow passage, The guide ring has a plurality of holes through which the injected material passes; The guide ring is fixed midway through the shaft of the needle valve and moves back and forth integrally with the needle valve when the needle valve moves back and forth, and the outer periphery of the guide ring slides against the bore of the flow passage, which is formed to the same diameter, to guide the forward and backward movement of the needle valve.

2. 2. The shut-off nozzle according to claim 1, wherein the plurality of holes are arranged on the circumference of any one of a plurality of imaginary circles having different diameters and centered about an axis of the guide ring.

3. A heating cylinder; A screw provided in the heating cylinder; A shut-off nozzle provided on the heating cylinder; The shut-off nozzle is an injection nozzle having a flow path formed therein; a needle valve provided in the flow passage coaxially with the injection nozzle and driven by a drive mechanism to be moved back and forth in the axial direction; A guide ring provided in the flow path, The needle valve has a cylindrical stem, the flow passage is formed in the injection nozzle with a uniform diameter over a predetermined length, and in the section in which the flow passage is formed with the uniform diameter, the shaft portion is provided coaxially with the injection nozzle and with a predetermined gap between the shaft portion and the bore of the flow passage, The guide ring has a plurality of holes through which the injected material passes; the guide ring is fixed midway through the shaft of the needle valve and moves back and forth integrally with the needle valve when the needle valve moves back and forth, and the outer periphery of the guide ring slides against the bore of the flow path, which is formed to the same diameter, to guide the forward and backward movement of the needle valve.

4. 4. The injection device according to claim 3, wherein the plurality of holes are arranged on the circumference of any one of a plurality of imaginary circles having different diameters and centered about an axis of the guide ring.

5. an injection device that injects resin; A mold clamping device that clamps a mold, The injection device is A heating cylinder; A screw provided in the heating cylinder; A shut-off nozzle provided on the heating cylinder; The shut-off nozzle is an injection nozzle having a flow path formed therein; a needle valve provided in the flow passage coaxially with the injection nozzle and driven by a drive mechanism to be moved back and forth in the axial direction; A guide ring provided in the flow path, The needle valve has a cylindrical stem, the flow passage is formed in the injection nozzle with a uniform diameter over a predetermined length, and in the section in which the flow passage is formed with the uniform diameter, the shaft portion is provided coaxially with the injection nozzle and with a predetermined gap between the shaft portion and the bore of the flow passage, The guide ring has a plurality of holes through which the injected material passes; the guide ring is fixed midway through the shaft of the needle valve and moves back and forth integrally with the needle valve when the needle valve moves back and forth, and the outer periphery of the guide ring slides against the bore of the flow path, which is formed to the same diameter, to guide the forward and backward movement of the needle valve.

6. 6. The injection molding machine according to claim 5, wherein the plurality of holes are arranged on the circumference of any one of a plurality of imaginary circles having different diameters and centered about an axis of the guide ring.

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