Injection unit and injection molding machine

Abstract

To prevent loosening of a connection between a heating cylinder and a nozzle adapter.SOLUTION: An injection device 3 includes: a heating cylinder 30 for heating and melting a resin material; an adapter screwed to one end of the heating cylinder 30; an injection nozzle 40 communicating with the heating cylinder 30 via the adapter; a pressing member 61 rotatable integrally with the adapter; and a bracket 70 connected to the pressing member 61. The adapter and the injection nozzle 40 are fixed to each other by the pressing members 61, 62. The bracket 70 regulates a rotation of the pressing member 61.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an injection molding machine for molding a resin member. [Background technology]

[0002] Injection molding machines that mold resin components (resin molded products) into desired shapes are known. A typical injection molding machine is composed of an injection device and a clamping device. The injection device melts a resin material and supplies the molten resin material (molten resin) to the clamping device. More specifically, the injection device injects (injects) the molten resin into the cavity of a mold.

[0003] The injection device has a heating cylinder for producing molten resin, an injection nozzle for injecting the molten resin, and a nozzle adaptor interposed between the heating cylinder and the injection nozzle. One end of the nozzle adaptor is connected to the heating cylinder, and the other end of the nozzle adaptor is connected to the injection nozzle. The molten resin produced by the heating cylinder flows through the nozzle adaptor into the injection nozzle and is injected from the tip of the injection nozzle. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6851703 Summary of the Invention [Problem to be solved by the invention]

[0005] If the connection between the heating cylinder and the nozzle adapter becomes loose, there is a risk of the molten resin leaking.

[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] In one embodiment, the injection device includes an injection nozzle that communicates with a heating cylinder via a nozzle adaptor, a presser member that can rotate integrally with the nozzle adaptor, and a bracket that is connected to the presser member. The nozzle adaptor and the injection nozzle are fixed to each other by the presser member. The bracket restricts the rotation of the presser member. Effect of the Invention

[0008] According to one embodiment, loosening of the connection between the heating cylinder and the nozzle adaptor is prevented. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram showing an injection molding machine according to an embodiment; [Diagram 2] FIG. 2 is a side view of the injection device shown in FIG. [Diagram 3] 3 is a partial cross-sectional view showing a connection portion between a heating cylinder and an injection nozzle shown in FIG. 2. [Figure 4] 4 is a cross-sectional view showing the nozzle adapter and the tip of the heating cylinder. FIG. [Figure 5A] FIG. 4 is a front view showing a schematic view of a pressing member and a bracket. [Figure 5B] FIG. 4 is a side view showing a schematic view of a pressing member and a bracket. [Figure 6] 13 is a partial cross-sectional view showing a modified example of the pressing member. FIG. [Figure 7] FIG. 11 is a partial cross-sectional view showing another modified example of the pressing member. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment will be described in detail with reference to the drawings. In all drawings for explaining the embodiment, the same reference numerals are used to designate members and devices having the same or substantially the same functions, and repeated description thereof will be omitted.

[0011] <Injection molding machine> FIG. 1 is a schematic diagram showing an injection molding machine according to this embodiment. FIG. 2 is a side view showing an injection unit according to this embodiment. The injection molding machine 1 is composed of a mold clamping unit 2 and an injection unit 3. Molds 11 and 12 are attached to the mold clamping unit 2. The mold clamping unit 2 opens and closes the attached molds 11 and 12. The injection unit 3 heats and melts a resin material. The injection unit 3 injects the melted resin material (molten resin) into the molds 11 and 12 attached to the mold clamping unit 2. More specifically, the injection unit 3 injects the molten resin into the cavities of the molds 11 and 12.

[0012] <Mold clamping device> The mold clamping device 2 includes a fixed platen 14, a mold clamping housing 15, and a movable platen 16, which are provided on a common bed 13. The fixed platen 14 is fixed to the bed 13. Meanwhile, the mold clamping housing 15 and the movable platen 16 are slidable on the bed 13.

[0013] The fixed platen 14 and the clamping housing 15 are connected by a plurality of tie bars 17. More specifically, the fixed platen 14 and the clamping housing 15 are connected by four tie bars 17. The movable platen 16 is slidable between the fixed platen 14 and the clamping housing 15 in the opposing direction between them.

[0014] A mold clamping mechanism 18 is provided between the mold clamping housing 15 and the movable platen 16. More specifically, a link-type mold clamping mechanism 18 is provided between the mold clamping housing 15 and the movable platen 16. From another perspective, a toggle mechanism is provided between the mold clamping housing 15 and the movable platen 16.

[0015] The mold clamping mechanism 18 moves the mold 11 attached to the movable platen 16 forward and backward relative to the mold 12 attached to the fixed platen 14. When the mold 11 comes into contact with the mold 12, the molds 11 and 12 are closed. On the other hand, when the mold 11 moves away from the mold 12, the molds 11 and 12 are opened. While the mold clamping mechanism 18 is closing the molds 11 and 12, the mold clamping mechanism 18 can press the mold 11 against the mold 12 so that the molds 11 and 12 do not open. The mold clamping mechanism 18 can be replaced with a direct pressure type mold clamping mechanism (mold clamping cylinder).

[0016] <Injection device> The injection device 3 is provided on a base 20 adjacent to the bed 13. The injection device 3 is composed of a heating cylinder 30, an injection nozzle 40, a shut-off nozzle 90, etc. The injection device 3 is driven by a nozzle touch device 21 in a direction approaching the mold clamping device 2 (forward), and also in a direction away from the mold clamping device 2 (rearward). In other words, the injection device 3 moves forward and backward (retracts) relative to the mold clamping device 2. When the injection device 3 moves forward to a predetermined position, the tip of the injection nozzle 40 comes into contact with the sprue bush of the mold 12.

[0017] A hopper 31 is provided at the rear end side of the heating cylinder 30. The hopper 31 is a supply port for supplying the resin material to the heating cylinder 30. The hopper 31 is firmly fixed to the heating cylinder 30 by a hopper flange 32. A supply path 32a that communicates with the hopper 31 and the heating cylinder 30 is provided inside the hopper flange 32. The resin material put into the hopper 31 is sent into the heating cylinder 30 via the supply path 32a. In some embodiments, a cooling mechanism is provided in the hopper flange 32 to prevent the resin material in the hopper 31 from softening or melting.

[0018] A screw 33 is provided inside the heating cylinder 30. The screw 33 is driven inside the heating cylinder 30 by a drive mechanism covered by a cover 34. From another perspective, the screw 33 rotates inside the heating cylinder 30. The screw 33 also moves linearly inside the heating cylinder 30. The direction of the linear movement of the screw 33 is the same as the moving direction of the injection unit 3 relative to the mold clamping unit 2. In other words, the screw 33 is driven linearly inside the heating cylinder 30 in a direction approaching the mold clamping unit 2 (forward) and a direction moving away from the mold clamping unit 2 (rearward).

[0019] The heating cylinder 30 melts the supplied resin material to produce molten resin. A heater for heating the heating cylinder 30 is provided around the heating cylinder 30. In this embodiment, a plurality of band heaters 35 are wound around the outer circumferential surface of the heating cylinder 30. The resin material supplied to the heating cylinder 30 is heated and melted by the heat generated by the band heaters 35 and the shear heat generated by the rotation of the screw 33.

[0020] <Manufacturing method for resin molded products> Next, a description will be given of an example of a procedure (process) for manufacturing a resin molded product using the injection molding machine 1 shown in Fig. 1. First, the molds 11 and 12 attached to the mold clamping device 2 are opened, and the injection device 3 is moved backward.

[0021] Thereafter, the resin material is charged into the hopper 31 of the injection device 3. For example, the resin material processed into beads or pellets is charged into the hopper 31. However, the resin material may be charged into the hopper 31 in advance before the injection device 3 is retracted.

[0022] The resin material put into the hopper 31 is supplied to the heating cylinder 30 through the supply path 32a. The resin material supplied to the heating cylinder 30 is heated and melted. The melted resin material (molten resin) is sent to the tip side of the heating cylinder 30 by the rotation of the screw 33. From another perspective, the molten resin is filled between the screw 33 and the injection nozzle 40.

[0023] Thereafter, the injection device 3 is moved forward, and the tip of the injection nozzle 40 is brought into contact with the sprue bush of the mold 12 (the molds 11 and 12 are closed in advance). Next, the screw 33 is moved forward within the heating cylinder 30. At this time, the screw 33 is not rotated. Then, the molten resin is injected (injected) from the tip of the injection nozzle 40 into the cavities of the molds 11 and 12.

[0024] The screw 33 continues to apply pressure (holding pressure) to the molten resin even after it has been injected into the cavity. The holding pressure is equal to or smaller than the pressure (injection pressure / primary pressure) used to inject (inject) the molten resin into the cavity. The molds 11 and 12 are cooled while maintaining the state in which pressure is applied to the molten resin in the cavity.

[0025] While the molds 11 and 12 are cooling, the screw 33 is rotated again to prepare for the next injection. Specifically, the screw 33 is rotated to send molten resin to the tip side of the heating cylinder 30. In other words, the molten resin to be injected next is filled between the screw 33 and the injection nozzle 40. As a result, the screw 33 is moved backwards by a reaction force. This process of moving the screw 33 backward while sending the molten resin forward is called "metering."

[0026] After the molds 11 and 12 have been cooled to a temperature below the solidification temperature of the molten resin in the cavity, the molds 11 and 12 are opened and the resin molded product is taken out.

[0027] By repeating the above process, resin molded products of the same shape can be manufactured continuously, i.e., resin molded products of desired shapes can be mass-produced.

[0028] <Injection nozzle and nozzle adapter> Next, the connection structure between the heating cylinder 30 and the injection nozzle 40 will be described. Fig. 3 is a partial cross-sectional view showing the connection between the heating cylinder 30 and the injection nozzle 40. A nozzle adaptor 50 is interposed between the heating cylinder 30 and the injection nozzle 40. The injection nozzle 40 is in communication with the heating cylinder 30 via the nozzle adaptor 50.

[0029] A resin flow path P1 is provided inside the injection nozzle 40, penetrating the injection nozzle 40 in the axial direction. An injection outlet 41 that communicates with the resin flow path P1 is provided at the tip of the injection nozzle 40. From another perspective, the injection outlet 41 is the outlet of the resin flow path P1. In addition, a flange 42 having an outer diameter larger than other portions is provided at the rear end side of the injection nozzle 40.

[0030] Inside the nozzle adapter 50, a resin flow path P2 is provided which penetrates the nozzle adapter 50 in the axial direction. One end of the resin flow path P2 communicates with the heating cylinder 30, and the other end of the resin flow path P2 communicates with the resin flow path P1 of the injection nozzle 40. As a result, the injection nozzle 40 communicates with the heating cylinder 30 via the nozzle adapter 50. From another perspective, a series of resin flow paths P is formed from the heating cylinder 30 to the injection port 41 of the injection nozzle 40. In the following description, the resin flow path P1 in the injection nozzle 40 may be referred to as the "nozzle flow path P1" and the resin flow path P2 in the nozzle adapter 50 may be referred to as the "adapter flow path P2" to distinguish them. The nozzle adapter 50 may also be abbreviated to "adapter 50".

[0031] <Connection end, middle part and flange part> 4 is a cross-sectional view showing the tip end of the heating cylinder 30 and the adapter 50. The adapter 50 is a metal member having a generally cylindrical shape. The adapter 50 is provided with a connection end 51, an intermediate portion 52, and a flange portion 53 along the axial direction. The connection end 51 is provided at one axial end side (rear end side) of the adapter 50, the flange portion 53 is provided at the other axial end side (tip side) of the adapter 50, and the intermediate portion 52 is provided between the connection end 51 and the flange portion 53.

[0032] That is, the connection end 51, the intermediate portion 52, and the flange portion 53 are arranged in this order from the rear end side to the front end side of the adapter 50. In other words, the connection end 51, the intermediate portion 52, and the flange portion 53 are arranged in this order from the upstream side to the downstream side of the resin flow path P2. As a result, the end face of the connection end 51 forms the bottom surface 50b of the adapter 50, and the end face of the flange portion 53 forms the top surface 50a of the adapter 50.

[0033] A screw 51a is formed on the outer circumferential surface of the connection end 51, and is coupled to the screw 30a formed on the inner circumferential surface of the heating cylinder 30. In other words, the region where the screw 51a is formed on the outer circumferential surface is the connection end 51.

[0034] The adapter 50 is fixed to the tip of the heating cylinder 30 by screwing the connection end 51 to the heating cylinder 30 (FIG. 3). From another perspective, the adapter 50 corresponds to a screw that is connected to the heating cylinder 30. In this case, the diameter D of the connection end 51 corresponds to the shaft diameter of the screw. For example, when the diameter D of the connection end 51 is 80 mm, the adapter 50 corresponds to an "M80" screw.

[0035] When the adapter 50 rotates to the right as viewed from the front (the flange 53 side), the screw connection of the adapter 50 to the heating cylinder 30 becomes stronger. At this time, the adapter 50 moves forward relative to the heating cylinder 30. On the other hand, when the adapter 50 rotates to the left as viewed from the front, the screw connection of the adapter 50 to the heating cylinder 30 becomes weaker. At this time, the adapter 50 moves backward relative to the heating cylinder 30. In other words, the adapter 50 corresponds to a right-handed screw. The rotation direction of the adapter 50 mentioned in the following description is the rotation direction as viewed from the front, unless otherwise specified.

[0036] The intermediate portion 52 has substantially the same outer diameter as the connection end portion 51. However, no screw corresponding to the screw 51a provided on the outer peripheral surface of the connection end portion 51 is provided on the outer peripheral surface of the intermediate portion 52. The flange portion 53 has an outer diameter larger than the connection end portion 51 and the intermediate portion 52, and is provided with a recess 54 in its center.

[0037] The adapter flow path P2 passes through the center of the adapter 50 in the axial direction. More specifically, the adapter flow path P2 passes through the radial centers of the connection end portion 51, the intermediate portion 52, and the flange portion 53 in the axial direction. As a result, the outlet P2b of the adapter flow path P2, which is connected to the nozzle flow path P1, is located at the bottom of the recess 54. More specifically, the bottom surface 54b of the recess 54 surrounds the outlet P2b of the adapter flow path P2.

[0038] The inlet P2a of the adapter flow path P2 is formed in a funnel shape. The bottom surface 50b of the adapter 50 (the end surface of the connection end portion 51) surrounds the inlet P2a of the adapter flow path P2.

[0039] <Pressing member> Referring again to Figure 3, the injection nozzle 40 and the adapter 50 are fixed to each other by two pressing members 61, 62. The pressing members 61, 62 are substantially annular metal members, and face each other with the flange 53 of the adapter 50 in between.

[0040] The pressing member 61 is disposed around the middle portion 52 of the adapter 50 and surrounds the middle portion 52. On the other hand, the pressing member 62 is disposed around the flange portion 42 of the injection nozzle 40 and surrounds the flange portion 42.

[0041] The pressing member 61 has a plurality of bolt holes 61a formed at equal intervals along the circumferential direction. The pressing member 62 has a plurality of through holes 62a formed at equal intervals along the circumferential direction. The pressing member 61 is positioned by one or more positioning pins 63, and the pressing member 62 is positioned by one or more positioning pins 64. When the pressing members 61, 62 are positioned by the positioning pins 63, 64, the corresponding bolt holes 61a and through holes 62a communicate with each other.

[0042] The pressing members 61, 62 are fixed to each other by a bolt 65 which passes through the through hole 62a and is screwed into the bolt hole 61a. Therefore, when the bolt 65 is tightened, a force acts on the pressing members 61, 62 to bring them closer to each other. Then, the pressing member 61 is pressed against the adapter 50, and the pressing member 62 is pressed against the injection nozzle 40. More specifically, the pressing member 61 is pressed against the bottom surface (back surface) of the flange 53 of the adapter 50, and the pressing member 62 is pressed against the top surface (front surface) of the flange 42 of the injection nozzle 40.

[0043] The pressing member 61 pressed against the flange portion 53 becomes rotatable integrally with the adapter 50. From another perspective, the pressing member 61 is pressed against the flange portion 53 with a force necessary and sufficient to couple the adapter 50 and the pressing member 61 so as to be rotatable integrally with each other.

[0044] The pressing member 62 pressed against the flange portion 42 presses the injection nozzle 40 against the adapter 50. More specifically, the pressing member 62 presses the rear end face of the injection nozzle 40 against the bottom surface 54b (FIG. 4) of the recess 54 to bring them into close contact. As a result, the injection nozzle 40 and the adapter 50 are fixed to each other. In addition, the nozzle flow path P1 and the adapter flow path P2 communicate with each other to form a resin flow path P.

[0045] The rear end of the injection nozzle 40 (the portion protruding rearward beyond the flange portion 42) is inserted into the recess 54 of the adapter 50. Thus, the nozzle flow path P1 and the adapter flow path P2 are connected within the recess 54.

[0046] <bracket> 2, a bracket 70 is connected to the pressing member 61. More specifically, one end of the bracket 70 is connected to the pressing member 61, and the other end of the bracket 70 is connected to the hopper flange 32 via a connecting member 71.

[0047] Fig. 5A is a front view showing the pressing member 61 and the bracket 70. Fig. 5B is a side view showing the pressing member 61 and the bracket 70. Two brackets 70 (bracket 70a, bracket 70b) are connected to the outer circumferential surface of the pressing member 61.

[0048] The two brackets 70a, 70b face each other with the pressing member 61 in between. From another perspective, the bracket 70a is connected to one radial side of the pressing member 61, and the bracket 70b is connected to the other radial side of the pressing member 61. More specifically, the brackets 70a, 70b are each connected to the pressing member 61 at positions that are 180 degrees apart in the circumferential direction.

[0049] Bracket 70 is a plate-like member formed from the same metal material (ductile material) as tie bar 17 (FIG. 1). One end of bracket 70 is provided with a fixed portion 72 that is connected to pressing member 61, and the other end of bracket 70 is provided with a fixed portion 73 that is connected to connecting member 71. Furthermore, the two fixed portions 72, 73 are connected by a connecting portion 74 that extends obliquely. However, bracket 70 is a single member, and the distinction between fixed portion 72, fixed portion 73, and connecting portion 74 is merely for convenience of explanation.

[0050] Two flat portions 66a, 66b are formed on the outer circumferential surface of the pressing member 61. The fixing portion 72 of the bracket 70a is fixed to one flat portion 66a by a bolt, and the fixing portion 72 of the bracket 70b is fixed to the other flat portion 66b by a bolt.

[0051] The fixing portion 73 of the bracket 70a is fixed to a tip of a connecting member 71 by a bolt, and the fixing portion 73 of the bracket 70b is fixed to a tip of another connecting member 71 by a bolt. The rear end of each connecting member 71 is fixed to the hopper flange 32 by a bolt.

[0052] <Bracket function> One end of the bracket 70 is connected to a pressing member 61 that rotates integrally with the adapter 50, and the other end of the bracket 70 is connected to a member (in this embodiment, the hopper flange 32) that does not rotate integrally with the adapter 50. Therefore, the rotation of the pressing member 61 is restricted by the bracket 70, and therefore the rotation of the adapter 50 is restricted.

[0053] When a large torque is applied to the adapter 50 and the adapter 50 rotates or moves, the pressing member 61 also rotates or moves. This generates stress in the bracket 70, causing the bracket 70 to elastically deform. The elastically deformed bracket 70 generates a force that attempts to return the pressing member 61 to its original position. This force is transmitted to the adapter 50 via the pressing member 61.

[0054] As described above, when the adapter 50 rotates left, the screw connection of the adapter 50 to the heating cylinder 30 weakens. The adapter 50 facing the heating cylinder 30 receives various forces from the molten resin. For example, the pressure of the molten resin fed into the adapter flow path P2 by the screw 33 acts on the adapter 50 as an axial force. As a result, a left-handed torque acts on the adapter 50, which may weaken the screw connection of the adapter 50 to the heating cylinder 30. In other words, the connection between the heating cylinder 30 and the adapter 50 may loosen.

[0055] When the adapter 50 rotates left due to the pressure of the molten resin or the like, the pressing member 61 also rotates left. Then, the bracket 70b shown in FIG. 5A is elastically deformed so as to be compressed, and the bracket 70a is elastically deformed so as to be expanded. Also, the adapter 50 retreats from the heating cylinder 30 as it rotates left. In other words, the adapter 50 moves forward, and the pressing member 61 also moves in the same direction. Then, the bracket 70a shown in FIG. 5B is pulled forward and elastically deformed so as to be expanded. At this time, the bracket 70b not shown in FIG. 5B is also pulled forward and elastically deformed so as to be expanded.

[0056] In short, when the adapter 50 rotates and retracts relative to the heating cylinder 30, a rotational force and a tension force act on the brackets 70a, 70b, causing the brackets 70a, 70b to elastically deform.

[0057] The elastically deformed brackets 70a, 70b attempt to return to their original state. Specifically, the brackets 70 compressed or stretched by a rotational force attempt to expand or contract in the direction opposite to the direction of the rotational force. At the same time, the brackets 70 stretched by a tension force attempt to contract in the direction opposite to the direction of the tension force.

[0058] Therefore, a clockwise rotational force (torque) is applied to the pressing member 61 and the adapter 50. At the same time, a tension is applied to the pressing member 61 and the adapter 50 to pull them back. As a result, the adapter 50 is returned to its original position. In other words, the expansion and contraction movement of the bracket 70 corrects the slackness of the adapter 50. The positioning pin 63 functions as a guide pin that guides the movement of the pressing member 61 when the pressing member 61 is returned to its original position by the expansion and contraction of the bracket 70.

[0059] 4, a receiving surface 36 that faces an end face (bottom surface 50b) of the adapter 50 is provided inside the heating cylinder 30. A washer 37 is disposed between the receiving surface 36 of the heating cylinder 30 and the bottom surface 50b of the adapter 50. By disposing the washer 37 between the receiving surface 36 and the bottom surface 50b, loosening of the adapter 50 is further prevented or suppressed.

[0060] Here, the action of the bracket 70 has been described taking as an example a case where the adapter 50 is rotated left. However, the bracket 70 also returns the adapter 50 and the pressing member 61 to their original positions by the same action as described above when the adapter 50 is rotated right.

[0061] Furthermore, the bracket 70 not only rotates the rotated adapter 50 in the opposite direction, but also restricts the rotation of the adapter 50 in the first place.

[0062] In this embodiment, the bracket 70 prevents and corrects loosening of the adapter 50. Therefore, it is not necessary to screw the adapter 50 to the heating cylinder 30 with a large torque using a special tool or a dedicated tool. For example, even if the adapter 50 is screwed to the heating cylinder 30 only by the force of a human hand, the adapter 50 will not come loose thereafter. The tightening torque obtained by the force of a human hand is generally 1200 Nm to 1500 Nm.

[0063] Also, the sealing performance of each mounting seat surface in the injection device 3 is maintained. For example, the sealing performance is maintained between the receiving surface 36 of the heating cylinder 30 and the bottom surface 50b of the adapter 50. Also, the sealing performance is maintained between the rear end surface of the injection nozzle 40 and the bottom surface 54b of the recess 54 of the adapter 50.

[0064] <Shut-off nozzle> 2 and 3 is attached to a connecting member 71. The shut-off nozzle 90 is provided with a needle valve 92 that is reciprocated by a drive mechanism (cylinder unit) 91, and opens and closes a nozzle flow path P1. The tip of the needle valve 92 is inserted into a needle hole 43 provided in the injection nozzle 40.

[0065] The needle valve 92 is driven to reciprocate between a first position where its tip enters the nozzle flow path P1 and a second position where its tip retracts from the nozzle flow path P1. When the needle valve 92 moves from the second position to the first position, the nozzle flow path P1 is closed by the tip of the needle valve 92. On the other hand, when the needle valve 92 moves from the first position to the second position, the nozzle flow path P1 that was closed by the tip of the needle valve 92 is opened.

[0066] By providing the shut-off nozzle 90, it is possible to quickly and reliably stop the injection of the molten resin from the injection nozzle 40. This advantage is particularly effective when the molten resin handled by the injection device 3 has high fluidity or foaming properties.

[0067] In this embodiment in which the rotation of the adapter 50 is restricted, the rotation of the injection nozzle 40 is also restricted. Therefore, when the needle valve 92 moves to the first position, the tip of the needle valve 92 always contacts a predetermined position in the nozzle flow path P1. As a result, the shutoff function is reliably ensured. In addition, the outer peripheral surface of the needle valve 92 and the inner peripheral surface of the needle hole 43 always contact uniformly. As a result, uneven wear of the needle valve 92 is avoided.

[0068] However, prevention of loosening of the nozzle adapter is also required for injection devices that are not equipped with a shut-off nozzle. By connecting the bracket 70 of this embodiment to the pressing member of another injection device that is not equipped with a shut-off nozzle, loosening of the nozzle adapter can be prevented and corrected in that injection device as well.

[0069] <Modification of the holding member> In the above embodiment, the injection nozzle and the nozzle adapter are fixed to each other by two pressing members. However, there may be only one pressing member. For example, as shown in Figures 6 and 7, there is also an embodiment in which the injection nozzle 40 and the adapter 50 are fixed to each other by one pressing member 60 that straddles the injection nozzle 40 and the adapter 50.

[0070] 6, an annular member 80 is disposed around the pressing member 60. The annular member 80 is welded to the tips of the two brackets 70a and 70b. Furthermore, three wedges 81 disposed at 120 degree intervals penetrate the annular member 80 and are press-fitted into the pressing member 60.

[0071] The holding member 60 with the wedges 81 pressed in is pressed against the injection nozzle 40 and the adapter 50. From another perspective, the wedges 81 apply an axial force to the holding member 60. As a result, the holding member 60 is able to rotate integrally with the adapter 50. Incidentally, each of the wedges 81 has a wedges 82 pressed in to prevent it from coming loose.

[0072] It is possible to appropriately change the number of wedges 81. For example, two wedges 81 may be arranged at intervals of 180 degrees, or four wedges 81 may be arranged at intervals of 90 degrees.

[0073] A plurality of bosses 67 each having a through hole 62a are welded to the outer peripheral surface of the pressing member 60 shown in Fig. 7. In addition, an annular member 80 is disposed around the pressing member 60 so as to surround the pressing member 60. The annular member 80 is welded to the tips of two brackets 70a, 70b. Although only one bracket 70b is shown in Fig. 7, the bracket 70a is disposed on the opposite side of the bracket 70b. In addition, the annular member 80 is partially cut out and is not a perfect circle.

[0074] The annular member 80 has a bolt hole 61a formed therein, which communicates with the through hole 62a of the boss 67. The pressing member 60 including the boss 67 and the annular member 80 are fixed to each other by a bolt 65 which passes through the through hole 62a and is screwed into the bolt hole 61a. Therefore, when the bolt 65 is tightened, a force acts on the pressing member 60 and the annular member 80 to bring them closer to each other. Then, the pressing member 60 is pressed against the injection nozzle 40, and the injection nozzle 40 is pressed against the adapter 50. As a result, the adapter 50, the injection nozzle 40, and the pressing member 60 are able to rotate together.

[0075] 6 and 7 rotate and move (forward or backward) relative to the heating cylinder 30, a rotational force and tension act on the brackets 70a, 70b, causing the brackets 70a, 70b to elastically deform. The elastically deformed brackets 70a, 70b generate a force that returns the adapter 50 and the pressing member 60 to their original positions, based on the same principle as described above.

[0076] The invention made by the inventor has been specifically described above based on an embodiment, but it goes without saying that the present invention is not limited to the above embodiment and can be modified in various ways without departing from the gist of the invention.

[0077] For example, in some embodiments, one or more brackets are connected to the presser member, and in other embodiments, some or all of the brackets are directly connected to a member or structure that does not rotate together with the adapter, without using a connecting member.

[0078] The material of the bracket can be changed as appropriate. However, since it is impossible for a stress exceeding the maximum injection pressure of the injection device to act on the bracket, if the elastic limit of the bracket is set to be greater than the maximum injection pressure of the injection device, plastic deformation of the bracket can be reliably avoided. [Explanation of symbols]

[0079] 1 injection molding machine 2 Mold clamping device 3 Injection device 11,12 Mold 13 Beds 14 Fixed plate 15 Clamping housing 16 Movable plate 17 Tie bar 18 Mold clamping mechanism 20 Foundations 21 Nozzle touch device 30 Heating Cylinder 30a Screw 31 Hopper 32 Hopper flange 32a Supply route 33 Screw 34 Cover 35 Band heater 36 Receiving surface 37 Washer 40 Injection nozzle 41 Injection port 42 Flange 43 Needle hole 50 Nozzle adapter (adapter) 50a top 50b bottom 51 Connection end 51a Screw 52 Middle section 53 Flange 54 Recess 54b Bottom 60, 61, 62 Pressing member 61a Bolt hole 62a through hole 63,64 Positioning pin 65 volts 66a,66b Flat part 67 Boss 70,70a,70b bracket 71 Connecting members 72,73 Fixed part 74 Connection 80 Annular member 81,82 Wedge 90 Shut-off nozzle 91 Drive mechanism (cylinder unit) 92 Needle valve D diameter P Resin flow path P1 Resin flow path (nozzle flow path) P2 Resin channel (adapter channel) P2a entrance P2b exit

Claims

1. An injection device that injects molten resin, a heating cylinder for heating and melting the resin material; a nozzle adapter that is screwed to one end of the heating cylinder; an injection nozzle communicating with the heating cylinder via the nozzle adapter; a pressing member that is rotatable integrally with the nozzle adapter; A bracket connected to the pressing member, the nozzle adapter and the injection nozzle are fixed to each other by the pressing member, The bracket restricts rotation of the pressing member.

2. 2. The injection device according to claim 1, wherein the bracket is elastically deformed in association with rotation of the pressing member, and generates a force for rotating the pressing member in a reverse direction.

3. A plurality of the brackets are provided.

3. The injection device according to claim 2, wherein the plurality of brackets include a first bracket that elastically deforms to be compressed when the pressing member rotates, and a second bracket that elastically deforms to be expanded when the pressing member rotates.

4. a hopper into which a resin material to be supplied to the heating cylinder is poured; a hopper flange that fixes the hopper to the heating cylinder and forms a supply passage that communicates with the hopper and the heating cylinder; 2. The injection device according to claim 1, wherein one end of said bracket is connected to said pressing member, and the other end of said bracket is connected to said hopper flange.

5. 5. The injection apparatus according to claim 4, wherein the bracket is connected to the hopper flange via a connecting member.

6. The nozzle adapter is provided with a connection end portion that is screw-coupled to an inner circumferential surface of the heating cylinder, and a flange portion that is disposed outside the heating cylinder, The pressing member includes two pressing members opposed to each other with the flange portion interposed therebetween, One of the two pressing members is pressed against the flange portion so as to be rotatable integrally with the nozzle adapter, The other of the two pressing members presses the injection nozzle against the nozzle adapter to bring them into close contact with each other, The injection device according to claim 1 , wherein the bracket is connected to the pressing member which is pressed against the flange portion.

7. A receiving surface is provided inside the heating cylinder so as to face an end surface of the connection end portion, The injection device according to claim 6 , wherein a washer is disposed between the end surface of the connecting end and the receiving surface of the heating cylinder.

8. 2. The injection device of claim 1, wherein the elastic limit of the bracket is greater than a maximum injection pressure of the injection device.

9. The injection device according to claim 1 , further comprising a shut-off nozzle for opening and closing a resin flow path provided in the injection nozzle.

10. a shut-off nozzle for opening and closing a resin flow path provided in the injection nozzle; The injection device of claim 5 , wherein the shut-off nozzle is attached to the connecting member.

11. An injection molding machine comprising a clamping device to which a mold is attached and an injection device that injects molten resin into the mold, The injection device is a heating cylinder for heating and melting the resin material; a nozzle adapter that is screwed to one end of the heating cylinder; an injection nozzle communicating with the heating cylinder via the nozzle adapter; a pressing member that is rotatable integrally with the nozzle adapter; A bracket connected to the pressing member, the nozzle adapter and the injection nozzle are fixed to each other by the pressing member, The bracket restricts rotation of the pressing member.

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