Shut-off nozzle, injection unit, and injection molding machine

Abstract

To provide a shut-off nozzle with which leaked resin can be easily cleaned.SOLUTION: A shut-off nozzle (24) includes: a nozzle body part (28); a needle valve (30) installed coaxially with this; a needle drive mechanism (32) consisting of a cylinder mechanism (40) and a spring receiver (41). The nozzle body part (28) includes a valve housing (37), and the valve housing (37) forms a needle hole (52) into which the needle valve (30) is inserted and a spring receiver hole (54). The spring receiver (41) is inserted into the spring receiver hole (54) in a direction perpendicular to an axial direction while being allowed to slide in the axial direction, and both ends of the spring receiver (41) are fixed to the cylinder mechanism (40). A rear end of the needle valve (30) is pushed at a center of the spring receiver (41). Expanded cleaning parts (56) are formed on both side surfaces of the valve housing (37) so as to be continuous with the spring receiver hole (54).SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] A shut-off nozzle installed in the injection unit of an injection molding machine is designed to open and close the injection flow path through which resin flows in the injection nozzle, preventing so-called dripping. There are various types of shut-off nozzles, such as the type described in Patent Document 1. This type of shut-off nozzle consists of a nozzle body and a needle valve installed at an angle to the nozzle body. The nozzle body has an oblique hole, or needle bore, that extends from its outer periphery to the injection flow path within the nozzle body. A needle valve is inserted into this needle bore so that it can move back and forth. When the needle valve is advanced, the injection flow path is closed, and when it is retracted, the injection flow path is opened. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 3-274125 Summary of the Invention [Problem to be solved by the invention]

[0004] Shut-off nozzles in which a needle valve is coaxially mounted on a nozzle body are also known. In such shut-off nozzles, the needle valve is inserted into an injection flow path formed in the nozzle body and is capable of moving forward and backward. When the needle valve moves forward, the injection flow path is closed at the tip of the nozzle body. In such shut-off nozzles, the needle valve is inserted into a needle hole formed in the nozzle body, with its rear end exposed. The needle valve is driven via its rear end by a predetermined needle drive mechanism. Resin gradually leaks out from the gap between the needle hole and the needle valve. The leaked resin must be removed by cleaning, but cleaning is difficult.

[0005] The present disclosure provides a shut-off nozzle that allows easy cleaning of leaked resin.

[0006] Other objects and novel features will become apparent from the description of this specification and the accompanying drawings. [Means for solving the problem]

[0007] The present disclosure relates to a shut-off nozzle including a nozzle body, a needle valve inserted coaxially with the nozzle body to open and close the outlet of a resin flow path, and a needle drive mechanism for driving the needle valve. The needle drive mechanism is composed of a cylinder mechanism and a spring support. The nozzle body includes a valve housing, which is formed with an axial needle hole into which the rear end of the needle valve is inserted and a spring support hole perpendicular to the axial direction. The spring support is inserted perpendicular to the axial direction while allowing axial sliding into the spring support hole, and both ends of the spring support are fixed to the cylinder mechanism. The center of the spring support is in contact with or connected to the rear end of the needle valve. The needle valve is driven via the spring support by the cylinder mechanism. Cleaning enlargements are formed on both sides of the valve housing, which are continuous with the spring support hole and have an enlarged shape. [Effects of the Invention]

[0008] The present disclosure allows the leaked resin to be easily removed and cleaned up in the enlarged cleaning section. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a front view showing an injection molding machine according to an embodiment of the present invention; [Figure 2A] 1 is a front cross-sectional view showing a shut-off nozzle according to an embodiment of the present invention. [Figure 2B] 1 is a front cross-sectional view showing a shut-off nozzle according to an embodiment of the present invention. [Figure 3] FIG. 2 is a perspective view showing a valve housing of the shut-off nozzle according to the present embodiment. [Figure 4A] 4 is a cross-sectional view of the valve housing of the shut-off nozzle according to the present embodiment, taken along line XX in FIG. 3. FIG. [Figure 4B] 4 is a cross-sectional view of a valve housing of the shut-off nozzle according to the present embodiment, taken along line YY in FIG. 3. FIG. [Figure 5] FIG. 2 is a perspective view showing a spring holder of the shut-off nozzle according to the present embodiment. [Figure 6A] 2 is a cross-sectional view showing a valve housing, a part of a needle valve, and a spring support of the shut-off nozzle according to the present embodiment. FIG. [Figure 6B] 3 is a cross-sectional view showing a valve housing and a spring support of the shut-off nozzle according to the present embodiment. FIG. [Figure 7] FIG. 10 is a cross-sectional view of a valve housing and a spring support of a shut-off nozzle according to a comparative example. [Figure 8A] FIG. 10 is a perspective view showing a spring support of a shut-off nozzle according to a modified example of the present embodiment. [Figure 8B] FIG. 10 is a cross-sectional view of a valve housing of a shut-off nozzle according to a modified example of the present embodiment. [Figure 8C] 8C is a cross-sectional view of a valve housing of a shut-off nozzle according to a modified example of the present embodiment, taken along line ZZ in FIG. 8B. DETAILED DESCRIPTION OF THE INVENTION

[0010] 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.

[0011] <Injection molding machine> 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.

[0012] <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.

[0013] <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 a shut-off nozzle 24 according to this embodiment, which will be described in detail next.

[0014] <Shut-off nozzle according to this embodiment> 2A, the shut-off nozzle 24 according to this embodiment includes a nozzle main body 28 having resin flow paths 26 and 27 formed therein, a needle valve 30 housed in the nozzle main body 28, and a needle drive mechanism 32 that drives the needle valve 30. When viewed with the central axis of the heating cylinder 19, which is disposed horizontally, the nozzle main body 28 is disposed approximately coaxially with the heating cylinder 19, and the needle valve 30 is disposed coaxially with the nozzle main body 28.

[0015] In this embodiment, the nozzle main body 28 is composed of three members: a nozzle base 34 attached to the heating cylinder 19, a nozzle tip 35 attached to the tip, and a valve housing 37 connecting the nozzle base 34 and the nozzle tip 35. The valve housing 37 according to this embodiment has a plurality of communication holes 38, 38, ... formed therein, which connect the resin flow path 26 in the nozzle base 34 with the resin flow path 27 in the nozzle tip 35.

[0016] The needle drive mechanism 32 is composed of an annular cylinder mechanism 40 provided to surround the outer periphery of the nozzle base 34, and a spring support 41 housed in the valve housing 37. The spring support 41 will be described in detail later, but it is connected to and driven by the cylinder mechanism 40. The needle valve 30 is driven by the spring support 41.

[0017] The cylinder structure 40 is driven by, for example, air. When air is supplied to the cylinder structure 40, the spring support 41 is pushed forward. This causes the needle valve 30 to move forward and close the resin flow path 27 in the nozzle tip 35. On the other hand, when the air supply to the cylinder structure 40 is stopped, the spring support 41 moves backward. This causes the needle valve 30 to move backward and open the resin flow path 27. Here, "forward" means moving in a direction (forward) approaching the mold clamping unit 2, and "backward" means moving in a direction (rearward) away from the mold clamping unit 2. The cylinder structure 40 may also be driven by other fluids such as hydraulic oil or water. The spring support 41 may also be driven by a drive mechanism other than the cylinder mechanism 40, such as an electric drive mechanism.

[0018] <Valve housing> A valve housing 37 according to this embodiment will now be described. As shown in FIGS. 2A and 3, the valve housing 37 is integrally formed with a base connection portion 43 connected to the nozzle base 34, a spring support housing portion 44 housing the spring support 41, and a tip connection portion 45 to which the nozzle tip 35 is attached. Male threads 47 and 48 are formed on the outer periphery of the base connection portion 43 and the tip connection portion 45, respectively, and as shown in FIG. 2A, these are attached to female threads 49 and 50 formed on the nozzle base 34 and the nozzle tip 35. FIG. 4A shows a cross-sectional view of the valve housing 37 taken along line XX in FIG. 3. The tip connection portion 45 has a needle bore 52 formed coaxially with the tip connection portion 45. The rear end of the needle valve 30 is inserted into this needle bore 52, as shown in FIG. 2A.

[0019] As shown in Figure 3, a spring support hole 54 is formed in the spring support storage portion 44 of the valve housing 37. The spring support hole 54 is a hole that passes through the spring support storage portion 44 perpendicular to the axial direction, and is designed to receive the spring support 41 (see Figure 2A), which will be described later. The needle hole 52 and the spring support hole 54 are connected, as shown in Figure 4A. Therefore, when the needle valve 30 (see Figure 2A) is inserted into the needle hole 52, its rear end comes into contact with the spring support 41, and when the spring support 41 slides, the needle valve 30 is driven.

[0020] The valve housing 37 according to this embodiment has several features related to the spring support hole 54. A cross-sectional view of the valve housing 37 taken along line YY in FIG. 3 is shown in FIG. 4B. The first feature of the valve housing 37 is that it is provided with enlarged cleaning portions 56. The enlarged cleaning portions 56 are fan-shaped and cut out from both sides of the spring support storage portion 44. These enlarged cleaning portions 56 are continuous with the spring support hole 54 and have a shape suitable for cleaning resin that leaks and accumulates in the spring support hole 54. While the enlarged cleaning portions 56 are fan-shaped in this embodiment, the shape is not limited to a fan shape as long as the spring support hole 54 is enlarged at both ends.

[0021] The second feature is that, as shown in Fig. 4A, a U-shaped groove 57 is formed on part of the surface of the spring support hole 54. The spring support 41 (see Fig. 2A), which will be described next, is in contact with the U-shaped groove 57, and as a result, resin that leaks out and accumulates in the spring support hole 54 can be pushed out into the enlarged cleaning portions 56, 56, as will be described later. In this embodiment, the U-shaped groove 57 does not remain within the spring support hole 54, but extends to the enlarged cleaning portions 56, 56, as shown in Fig. 4B.

[0022] <Spring Uke> As shown in FIG. 5, the spring support 41 according to this embodiment has a flat rod shape. Both ends of the spring support 41 are partially cut out to form stepped portions 58, 58. These stepped portions 58, 58 are fixed to the cylinder mechanism 40 (see FIG. 2A), and the spring support 41 is driven by the cylinder mechanism 40. In FIG. 5, the top surface 60 of the spring support 41 is flat. The center of this top surface 60 presses the rear end of the needle valve 30 (see FIG. 2A). The spring support 41 according to this embodiment is characterized in that its bottom surface is formed as a convexly curved surface 61. This convexly curved surface 61 comes into contact with the U-shaped groove 57 (see FIG. 4B), thereby squeezing out any leaked resin. The curvature of the convexly curved surface 61 is slightly greater than that of the U-shaped groove 57.

[0023] <Shut-off nozzle action> The operation of the shut-off nozzle 24 according to this embodiment will now be described. As shown in FIG. 6A, the spring support 41 is inserted into the spring support hole 54 in a state in which axial sliding is permitted. The rear end of the needle valve 30 contacts the upper surface 60 of the spring support 41. As shown in Fig. 1, the cylinder mechanism 40 is driven to move the spring support 41 backward. When this is done, the force with which the spring support 41 presses the needle valve 30 becomes substantially zero. When the screw 20 in the injection device 2 (see Fig. 1) is driven in the axial direction, the resin pressure increases in the resin flow path 27. The needle valve 30 has a tapered tip, so it moves backward due to the resin pressure. This opens the resin flow path 27, allowing the resin to be injected.

[0024] The cylinder mechanism 40 is driven to advance the spring support 41. As a result, as shown in FIG. 2B, the spring support 41 slides within the spring support hole 54 and pushes the needle valve 30. The tip of the needle valve 30 closes the outlet of the resin flow path 27. This prevents the resin from dripping.

[0025] When the shut-off nozzle 24 is operated for a long period of time, resin gradually leaks from the gap between the needle hole 52 and the needle valve 30. The leaked resin 63 accumulates in the spring support hole 54, as shown in FIG. 6A. As shown in FIG. 2A, the cylinder mechanism 40 is driven to retract the spring support 41. This causes the resin 63 (see FIG. 6A) to be pushed by the U-shaped groove 57 and the convex curved surface 61. As the resin 63 is pushed, it is pushed out into the enlarged cleaning portions 56, 56, as indicated by arrows 65, 65, ... in FIG. 6B. In other words, the leaked resin does not remain in the spring support hole 54 but moves to the enlarged cleaning portions 56, 56. The enlarged cleaning portions 56, 56 are relatively wide, making them easy to clean during maintenance.

[0026] <Comparative Example> FIG. 7 shows a cross section of a valve housing 102 and a spring support 103 provided in a shut-off nozzle 101 according to a comparative example. This valve housing 102 also has communicating holes 105, 105, ..., and, although not shown, needle holes are drilled into which needle valves are inserted. However, the spring support hole 108 formed in the valve housing 102 according to the comparative example differs from that of the valve housing 37 according to the present embodiment (see FIG. 6B). That is, the spring support hole 108 does not have the cleaning enlarged portions 56, 56 formed in the valve housing 37 according to the present embodiment. Therefore, in the valve housing 37 according to the comparative example, leaked resin tends to accumulate in the area indicated by the reference numeral 110, making cleaning difficult.

[0027] <Modification> The shut-off nozzle 24 according to this embodiment can be modified in various ways. Fig. 8A shows a modified spring holder 41A, and Figs. 8B and 8C show modified valve housings 37A. Other components are identical to those shown in Figs. 1, 2A, etc., and therefore will not be described further. The modified spring holder 41A has a modified bottom surface, as shown in Fig. 8A. Specifically, the convex curved surface 61A has a constant length near the center, but side convex curved surfaces 67, 67 of different heights are formed on both sides. Because the convex curved surface 61A and the side convex curved surfaces 67, 67 have different heights, their connecting portions 68, 68 are formed as gently sloping curved surfaces.

[0028] As shown in Figure 8B and Figure 8C, which is a ZZ cross section of Figure 8B, in a modified valve housing 37A, a U-shaped groove 57A is formed only in the area of ​​the spring support hole 54. Recessed grooves 70, 70 with a different depth from the U-shaped groove 57A are formed in the cleaning enlarged portions 56, 56. Because the U-shaped groove 57A and the recessed grooves 70, 70 have different depths, their connecting portions 71, 71 are formed into gently curved, inclined surfaces.

[0029] In this modification, the expanded cleaning portions 56, 56 are also formed, making it easy to clean up any leaked resin. The U-shaped groove 57A in the spring support hole 54 (see FIG. 8B) and the convex curved surface 61A in the spring support 41A (see FIG. 8A) have the effect of pushing out resin that accumulates in the spring support hole 54 into the expanded cleaning portions 56, 56. Furthermore, in the shut-off nozzle 24 according to this modification, the recessed grooves 70, 70 are shallow, and the connecting portions 71, 71 are formed as gently inclined surfaces, thereby mitigating stress concentration in these portions. This prevents deterioration of the shut-off nozzle 24.

[0030] <Other variations> In the shut-off nozzle 24 (see FIG. 2A) according to this embodiment, the rear end of the needle valve 30 is in contact with the spring support 41. However, the rear end of the needle valve 30 and the spring support 41 may be fixed to each other.

[0031] 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]

[0032] 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 Shut-off nozzle 26 Resin flow path 27 Resin flow path 28 nozzle body 30 needle valve 32 needle drive mechanism 34 nozzle base 35 Nozzle tip 37 Valve housing 38 communicating hole 40 cylinder mechanism 41 Spring holder 43 Base connection part 44 Spring holder storage section 45 Tip connection section 47 Male thread 48 Male thread 49 Female thread 50 Female thread 52 Needle hole 54 Spring support hole 56 Cleaning expansion part 57 U-shaped groove 58 Stepped portion 60 Top surface 61 Convex curved surface 63 Resin 67 Lateral convex curved surface 68 Connection 70 concave groove 71 connection part

Claims

1. a nozzle body having a resin flow path formed therein; a needle valve that is inserted coaxially into the nozzle body and that opens and closes the outlet of the resin flow path; a needle drive mechanism that drives the needle valve, The needle drive mechanism includes a cylinder mechanism provided in the nozzle body portion; a spring support that transmits the driving force of the cylinder mechanism to the needle valve, the nozzle body includes a valve housing; The valve housing is formed with an axial needle hole into which the rear end of the needle valve is inserted and a spring support hole perpendicular to the axial direction, The spring support is inserted into the spring support hole in a direction perpendicular to the axial direction while being allowed to slide in the axial direction, both ends of the spring support are fixed to the cylinder mechanism, and the central portion of the spring support is in contact with or connected to the rear end of the needle valve, so that when the cylinder mechanism is driven, the needle valve advances in the axial direction via the spring support to close the outlet. The shut-off nozzle has cleaning enlarged portions formed on both side surfaces of the valve housing, the cleaning enlarged portions being continuous with the spring support holes and having a shape that enlarges the spring support holes.

2. The shut-off nozzle of claim 1 , wherein the cleaning enlargement is formed in a fan shape.

3. The spring support has a convex curved surface of a predetermined length formed on the opposite side to the surface that contacts the needle valve, 3. The shut-off nozzle according to claim 1, wherein the spring support hole is formed with a U-shaped groove that is a U-shaped groove with which the convex curved surface comes into contact when the spring support retracts.

4. 4. The shut-off nozzle according to claim 3, wherein the curvature of the convex curved surface is greater than the curvature of the U-shaped groove.

5. 4. The shut-off nozzle according to claim 3, wherein the cleaning enlarged portion is formed with a recessed groove with which the spring support comes into contact when the spring support is retracted.

6. The shut-off nozzle according to claim 5 , wherein the concave groove and the U-shaped groove are smoothly connected via an inclined surface.

7. A heating cylinder; a screw contained in the heating cylinder; a shut-off nozzle provided on the heating cylinder; The shut-off nozzle includes a nozzle body having a resin flow path formed therein; a needle valve that is inserted coaxially into the nozzle body and that opens and closes the outlet of the resin flow path; a needle drive mechanism that drives the needle valve, The needle drive mechanism includes a cylinder mechanism provided in the nozzle body portion; a spring support that transmits the driving force of the cylinder mechanism to the needle valve, the nozzle body includes a valve housing; The valve housing is formed with an axial needle hole into which the rear end of the needle valve is inserted and a spring support hole perpendicular to the axial direction, The spring support is inserted into the spring support hole in a direction perpendicular to the axial direction while being allowed to slide in the axial direction, both ends of the spring support are fixed to the cylinder mechanism, and the center portion is in contact with or connected to the rear end portion of the needle valve, so that when the cylinder mechanism is driven, the needle valve advances in the axial direction via the spring support to close the outlet. In the injection device, on both side surfaces of the valve housing, there are formed cleaning enlarged portions which are continuous with the spring support holes and have a shape which enlarges the spring support holes.

8. 8. The injection device according to claim 7, wherein the cleaning enlarged portion is formed in a fan shape.

9. The spring support has a convex curved surface of a predetermined length formed on the opposite side to the surface that contacts the needle valve, 9. The injection device according to claim 7, wherein the spring support hole is formed with a U-shaped groove that is a U-shaped groove with which the convex curved surface comes into contact when the spring support retracts.

10. The injection device according to claim 9, wherein the curvature of the convex curved surface is greater than the curvature of the U-shaped groove.

11. The injection device according to claim 9, wherein the cleaning enlarged portion is formed with a recessed groove with which the spring support comes into contact when the spring support is retracted.

12. The injection device according to claim 11, wherein the concave groove and the U-shaped groove are smoothly connected via an inclined surface.

13. an injection device that injects resin; a mold clamping device that clamps the mold, the injection device comprises a heating cylinder; a screw contained in the heating cylinder; a shut-off nozzle provided on the heating cylinder; The shut-off nozzle includes a nozzle body having a resin flow path formed therein; a needle valve that is inserted coaxially into the nozzle body and that opens and closes the outlet of the resin flow path; a needle drive mechanism that drives the needle valve, The needle drive mechanism includes a cylinder mechanism provided in the nozzle body portion; a spring support that transmits the driving force of the cylinder mechanism to the needle valve, the nozzle body includes a valve housing; The valve housing is formed with an axial needle hole into which the rear end of the needle valve is inserted and a spring support hole perpendicular to the axial direction, The spring support is inserted into the spring support hole in a direction perpendicular to the axial direction while being allowed to slide in the axial direction, both ends of the spring support are fixed to the cylinder mechanism, and the center portion is in contact with or connected to the rear end portion of the needle valve, so that when the cylinder mechanism is driven, the needle valve advances in the axial direction via the spring support to close the outlet. an injection molding machine, wherein an enlarged cleaning portion is formed on each side surface of the valve housing, the enlarged cleaning portion being continuous with the spring support hole and having an enlarged shape of the spring support hole.

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