Injection device and injection molding machine

Abstract

To provide an injection device in which a driving device is hardly damaged.SOLUTION: The injection device 3 has a front plate 41 that supports the injection cylinder 31, a rear plate 43 that supports the drive mechanism 33, an intermediate plate 42 that is positioned between the front plate 41 and the rear plate 43 and rotatably supports the screw 32, an upper connection member 45 that connects the front plate 41 and the rear plate 43, and a lower connection member 46 that is positioned below the upper connection member 45 and connects the front plate 41 and the rear plate 43. The lower connection member 46 supports the intermediate plate 42 so as to be movable in the axial direction X of the injection cylinder 31, the rear plate 43 includes the support portion 61 that supports the drive mechanism 33 and is connected to the upper connection member 45, and the base portion 62 connected to the support portion 61 and the lower connection member 46, and the rigidity of the base portion 62 in the axial direction X is smaller than that of the support portion 61.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an injection unit and an injection molding machine. [Background technology]

[0002] An injection molding machine is equipped with an injection device for injecting injection material. Patent Document 1 describes an injection device that includes a front plate, an intermediate plate, and a rear plate. The front plate supports an injection cylinder that houses a screw, the intermediate plate rotatably supports the screw, and the rear plate supports a drive mechanism for the screw. The front plate and rear plate are connected by a connecting member. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6147813 Summary of the Invention [Problem to be solved by the invention]

[0004] During injection, the front plate receives a reaction force in the opposite direction to the injection direction. This reaction force is transmitted to the rear plate via the connecting member. This reaction force causes the rear plate to deform, making the drive unit more susceptible to damage.

[0005] An object of the present disclosure is to provide an injection device in which damage to a drive device is unlikely to occur. [Means for solving the problem]

[0006] The injection device of the present disclosure includes a front plate that supports an injection cylinder, a rear plate that supports a drive mechanism for the screw, an intermediate plate that rotatably supports the screw, an upper connecting member that connects the front plate and the rear plate, and a lower connecting member that connects the front plate and the rear plate. The lower connecting member supports the intermediate plate so that it can move in the axial direction of the injection cylinder. The rear plate has a support portion that supports the drive mechanism and is connected to the upper connecting member, and a base portion that is connected to the support portion and the lower connecting member, and the base portion has lower axial rigidity than the support portion. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide an injection device in which damage to the drive device is unlikely to occur. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a schematic front view of an injection molding machine according to a first embodiment. [Figure 2] FIG. 2 is a front view of the injection unit of the injection molding machine shown in FIG. [Figure 3A] FIG. 3 is a perspective view of some members of the injection device shown in FIG. 2. [Figure 3B] FIG. 3B is a side view seen from direction A in FIG. 3A. [Figure 4] FIG. 10 is a perspective view of some members of the injection device of Comparative Example 1. [Figure 5A] 10 is a schematic diagram showing deformation of a rear plate in Comparative Example 1. FIG. [Figure 5B] 10 is a schematic view showing deformation of a rear plate in Comparative Example 2. FIG. [Figure 5C] 5A and 5B are schematic diagrams illustrating deformation of a rear plate in the first embodiment. [Figure 6A] FIG. 10 is a side view of some members of an injection device according to a second embodiment. [Figure 6B] FIG. 10 is a side view of some members of an injection device according to a third embodiment. [Figure 7A] FIG. 10 is a perspective view of some members of an injection device according to a fourth embodiment. [Figure 7B] FIG. 7B is a side view seen from the direction A in FIG. 7A. [Figure 8] FIG. 11 is a perspective view of some members of an injection device according to a fifth embodiment. [Figure 9] FIG. 13 is a perspective view of some members of an injection device according to a sixth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, several embodiments of the present invention will be described with reference to the drawings. In the following description and drawings, the axial direction of the injection cylinder will be referred to as the X direction. The X direction is parallel to the horizontal direction. The direction from the injection unit to the clamping unit, or the injection direction, will be referred to as the +X direction, and the direction from the clamping unit to the injection unit will be referred to as the -X direction. The horizontal direction perpendicular to the X direction will be referred to as the Y direction, and the vertical direction will be referred to as the Z direction. The Z direction is perpendicular to the X and Y directions. The vertically upward direction will be referred to as the +Z direction, and the vertically downward direction will be referred to as the -Z direction.

[0010] (First embodiment) <Overall structure> 1 shows a schematic front view of an injection molding machine 1 according to the first embodiment. The injection molding machine 1 is generally composed of a mold clamping device 2 that fixes and opens and closes a mold, and an injection device 3 that heats, melts, and injects the material to be injected.

[0011] <Mold clamping device 2> The mold clamping device 2 includes a fixed platen 22 fixed on a bed 21 and having a fixed mold M1 attached thereto, a mold clamping housing 24 slidable on the bed 21, and a movable platen 23 slidable on the bed 21 and having a movable mold M2 attached thereto. The fixed platen 22 and the mold clamping housing 24 are connected by a plurality of tie bars 25. A mold clamping mechanism 26 for opening and closing the mold is provided between the movable platen 23 and the mold clamping housing 24. The mold clamping mechanism 26 is composed of a toggle mechanism, but may also be composed of a hydraulic mold clamping cylinder.

[0012] <Injection device 3> The injection device 3 is provided on a base 31. The injection device 3 includes an injection cylinder 31, a screw 32 built into the injection cylinder 31, and a drive mechanism 33 that drives the screw 32. The drive mechanism 33 drives the screw 32 to rotate and also drives it in the X direction. The drive mechanism 33 is covered with a cover 34. A hopper 35 that supplies the material to be injected is provided near the end of the injection cylinder 31 in the -X direction. An injection nozzle 36 that injects the material is provided at the tip of the injection cylinder 31 in the +X direction.

[0013] <Support structure of drive mechanism 33> Fig. 2 is a front view of the injection unit 3, Fig. 3A is a perspective view of some members of the injection unit 3, and Fig. 3B is a side view seen from direction A in Fig. 3A. The injection unit 3 has a front plate 41 that supports the injection cylinder 31, a rear plate 43 located on the -X direction side of the front plate 41, and an intermediate plate 42 located between the front plate 41 and the rear plate 43 in the X direction. The intermediate plate 42 and the rear plate 43 support a drive mechanism 33 for the screw 32. The -X direction end of the screw 32 is rotatably supported by the intermediate plate 42. The front plate 41 has a through hole 41A through which the screw 32 passes, and the rear plate 43 has a through hole 43A through which a ball screw 55 (described later) passes and to which a bearing 57 is attached.

[0014] As shown in FIG. 3A , the injection unit 3 has at least one (two in this embodiment) upper connecting member 45 connecting the front plate 41 and the rear plate 43. The two upper connecting members 45 are located on both sides of the central axis CL of the injection cylinder 31 in the Y direction (or when viewed from the Z direction). The injection unit 3 has at least one (two in this embodiment) lower connecting member 46 connecting the front plate 41 and the rear plate 43. The two lower connecting members 46 are located lower than the two upper connecting members 45. The two lower connecting members 46 are located on both sides of the central axis CL of the injection cylinder 31 in the Y direction (or when viewed from the Z direction). The two lower connecting members 46 may be located directly below the two upper connecting members 45, or may be offset in the Y direction from the two upper connecting members 45.

[0015] The two lower connection members 46 support the intermediate plate 42 movably in the X direction. Specifically, each of the two lower connection members 46 includes one guide rail 47 that movably supports the intermediate plate 42. As shown in Fig. 2, the intermediate plate 42 includes a linear guide 48, and the linear guide 48 is guided by the guide rail 47, allowing the intermediate plate 42 to move in the X direction.

[0016] As shown in FIG. 2, the injection unit 3 includes a support plate 44 that supports the front plate 41 and the rear plate 43, and a nozzle touch device 49. The nozzle touch device 49 connects the support plate 44 to the fixed plate 22. The nozzle touch device 49 is configured, for example, by a mechanism using a hydraulic cylinder or a mechanism using a ball screw. The nozzle touch device 49 drives the plates 41 to 43, the support plate 44, the upper and lower connecting members 45 and 46, the drive mechanism 33, the injection cylinder 31, and the like, in the X direction as a whole, thereby causing the injection nozzle 36 to touch the sprue bushing (not shown) of the mold. The two lower connecting members 46 may be in contact with the support plate 44 or may be separated from it, but are not constrained by it.

[0017] <Drive mechanism 33 of injection unit 3> The drive mechanism 33 has a plasticizing motor 51 provided on the intermediate plate 42 and a rotation transmission mechanism 52. The rotation transmission mechanism 52 is composed of a pulley connected to the plasticizing motor 51, a timing belt wound around the pulley, etc. The plasticizing motor 51 drives the screw 32 to rotate via the rotation transmission mechanism 52.

[0018] The drive mechanism 33 has a ball screw 55 located between the rear plate 43 and the intermediate plate 42. The ball screw 55 is rotatably supported by the rear plate 43 via a bearing 57. The drive mechanism 33 has an injection motor 53 provided on the rear plate 43, and a rotation transmission mechanism 54. The rotation transmission mechanism 54 is made up of a pulley connected to the injection motor 53, a timing belt wound around the pulley, and the like. The injection motor 53 rotates the ball screw 55 via the rotation transmission mechanism 54.

[0019] A ball nut 56 that meshes with the ball screw 55 is fixed to the intermediate plate 42. Because the relative position of the ball screw 55 in the X direction with respect to the rear plate 43 is fixed, when the ball screw 55 rotates, the ball nut 56 moves in the X direction along the ball screw 55. This drives the intermediate plate 42 and the screw 32 supported by the intermediate plate 42 in the X direction.

[0020] <Configuration of rear plate 43> 3A and 3B, the rear plate 43 has a support portion 61 that supports the drive mechanism 33, and a base portion 62 that is connected to the support portion 61. A through hole 43A that supports the bearing 57 is formed in the center of the support portion 61. An upper connecting member 45 is connected to the support portion 61, and a lower connecting member 46 is connected to the base portion 62. The support portion 61 and the base portion 62 can be integrally formed by casting or welding. The support portion 61 has a generally annular shape when viewed in the X direction, but the shape is not limited thereto.

[0021] The base portion 62 is composed of two legs 63 and a base plate 64 connected to the two legs 63. The base plate 64 is a rectangular plate with its long axis in the Y direction, and the lower connecting member 46 is connected to the base plate 64. The two legs 63 are provided on both sides of the central axis CL of the injection cylinder in the Y direction (or when viewed from the Z direction). The two legs 63 can have the same shape. The upper ends of the two legs 63 in the Z direction are connected to the position that protrudes most in the Y direction of the support portion 61, but the connection position with the support portion 61 is not limited. The support portion 61, the two legs 63, and the base plate 64 form a hollow portion 65 that penetrates in the X direction. When produced by casting, the hollow portion 65 can be formed by casting.

[0022] The average dimension T3 in the X direction of each of the two legs 63 is smaller than the average thickness T2 (average dimension in the X direction) of the support part 61. Alternatively, the average dimension T3 in the X direction of each leg 63 is smaller than the thickness T4 in the X direction of the part of the support part 61 where each leg 63 is connected. In a modified example, T3 = T2 or T4 = T2 may be satisfied.

[0023] 4 is a perspective view of some components of the injection device of Comparative Example 1, seen from the same direction as FIG. 3A. The injection device has a front plate 41, a rear plate 43, an intermediate plate 142, and two connecting members 145. The front plate 41 and the rear plate 43 have the same configuration as in the first embodiment. The two connecting members 145 are provided on both sides of the central axis CL of the injection cylinder 31 in the Y direction (or viewed from the Z direction), and connect the front plate 41 and the rear plate 43. Guide rails 47 are provided on the upper surfaces of the two connecting members 145, respectively, and the intermediate plate 142 is supported by the guide rails 47 and moves in the X direction.

[0024] FIG. 5A schematically shows the deformation of the rear plate 43 caused by the reaction force during injection. The bearing 57 is omitted from FIGS. 5A to 5C. The injection cylinder 31 receives a reaction force in the -X direction during injection. This reaction force is transmitted from the front plate 41 to the rear plate 43 via the two connecting members 145. Because the front plate 41 has a complex shape with many openings and notches, the rear plate 43 may receive a force not only in the -X direction but also in the Z direction. Since the injection cylinder 31 is rotated around the Z axis at the position of the front plate 41, the rear plate 43 is simply resting on the support plate 44 by its own weight. For this reason, the rear plate 43 may lift up when subjected to a force in the +Z direction.

[0025] When rear plate 43 lifts up, ball screw 55, which is supported by rear plate 43 via bearing 57, tilts from the horizontal direction (X direction). Because intermediate plate 142 does not deform significantly, ball nut 56 does not tilt significantly from the horizontal direction. As a result, the center line of ball screw 55 tilts with respect to the center line of ball nut 56, making ball screw 55 prone to damage.

[0026] 4, the connecting member 145 is likely to bend inward in the Y direction when subjected to a reaction force during injection. This causes the linear guide 48 to bend inward as well, which can loosen the fixing bolts (not shown) of the linear guide 48 and cause deformation or damage to the linear guide 48. This can also reduce the parallelism of the two guide rails 47, which can increase resistance when the intermediate plate 42 travels and reduce its ability to move in a straight line.

[0027] Deformation of the connecting member 145 can be reduced by placing the connecting member 145 downward, as in Comparative Example 2 shown by the dashed line in FIG. 4. This is because placing the connecting member 145 downward makes the connecting member 145 less susceptible to the reaction force during injection. However, because the upper part of the rear plate 43 is not constrained in the X direction, the upper part of the rear plate 43 deforms so that it tilts backward (in the -X direction), as shown in FIG. 5B. This causes the center line of the ball screw 55 to tilt with respect to the center line of the ball nut 56, making the ball screw 55 prone to damage. Therefore, it is difficult to reduce the tilt of the ball screw 55 in Comparative Example 2 as well.

[0028] 5C shows deformation of the rear plate 43 in this embodiment. The base portion 62 has less rigidity in the X direction than the support portion 61, and is therefore more likely to deform in the X direction. Deformation of the rear plate 43 caused by the reaction force during injection is mainly absorbed by the base portion 62. Specifically, shear deformation of the leg portion 63 causes the support portion 61 to move substantially in the -X direction without tilting significantly. Compared to comparative examples 1 and 2, the center line of the ball screw 55 is less likely to tilt relative to the center line of the ball nut 56, and damage to the ball screw 55 is less likely to occur.

[0029] (Second embodiment) FIG. 6A is a side view of the injection device 3 of the second embodiment, seen from the same direction as FIG. 3B. The configuration and effects that will not be described are the same as those of the first embodiment. In this embodiment, the base portion 62 is composed of only one leg portion 66 and a base plate 64 connected to the one leg portion 66. The base plate 64 can be configured in the same way as in the first embodiment. The one leg portion 66 is connected to the center of the support portion 61 in the Y direction, i.e., to the lowest part of the support portion 61. In this embodiment, it is easy to reduce the rigidity of the leg portion 66.

[0030] (Third embodiment) FIG. 6B is a side view of the injection device 3 of the third embodiment, seen from the same direction as FIG. 3B. The configuration and effects not described are the same as those of the first embodiment. In this embodiment, the base portion 62 is composed of a plate-shaped portion 67 and a base plate 64 connected to the plate-shaped portion 67. The plate-shaped portion 67 has at least one (multiple in this embodiment) through-hole 68 extending in the X direction. When multiple through-holes 68 are provided, the multiple through-holes 68 can be arranged line-symmetrically around the Z-axis Z1 passing through the central axis CL of the injection cylinder 31. The through-hole 68 can be formed by casting, similar to the hollow portion 65 of the first embodiment. The rigidity of the plate-shaped portion 67 can be finely adjusted by changing the arrangement, shape, number, etc. of the through-holes 68.

[0031] (Fourth embodiment) FIG. 7A is a perspective view similar to FIG. 3A of an injection device 3 of a fourth embodiment, and FIG. 7B is a side view seen from direction A in FIG. 7A. The configuration and effects that will not be described are the same as those of the first embodiment. In this embodiment, the base portion 62 is composed of a plate-shaped portion 69 and a base plate 64 connected to the plate-shaped portion 69. Unlike the plate-shaped portion 67 of the third embodiment, the plate-shaped portion 69 of this embodiment does not have a through-hole. The average thickness T5 (average dimension in the X direction) of the plate-shaped portion 69 is smaller than the average thickness T2 (average dimension in the X direction) of the support portion 61. Because there are no through-holes in this embodiment, the structure of the base portion 62 is simple and easy to manufacture.

[0032] (Fifth embodiment) FIG. 8 is a perspective view similar to FIG. 3A of the injection device 3 of the fifth embodiment. The configuration and effects that will not be described are the same as those of the first embodiment. For convenience, only a portion of the front upper connection member 45 is shown, but it is connected to the rear plate 43 as in the other embodiments. At least one lower connection member 46 is one lower connection member 46, and one lower connection member 46 is provided with two guide rails 47 that movably support the intermediate plate 42. The position of the lower connection member 46 is not limited, but it is preferably located in a position that overlaps with the central axis CL of the injection cylinder 31 when viewed in the Z direction.

[0033] The lower connecting member 46 has a large Y-direction dimension and high rigidity in the Y direction, and therefore is less likely to deform in the Y direction. For example, bending of the connecting member 145 as shown in Fig. 4 is less likely to occur, which further suppresses deformation of the guide rail 47 and the linear guide 48. The configuration of the support part 61 is not limited, and therefore this embodiment can be combined with the first to fifth embodiments.

[0034] (Sixth embodiment) 9 is a perspective view similar to FIG. 3A of the injection device 3 of the sixth embodiment. The configuration and effects that will not be described are the same as those of the first embodiment. At least one upper connecting member 45 is one upper connecting member 45. The position of one upper connecting member 45 is not limited, but it is preferable that it is directly above the central axis CL of the injection cylinder. [Explanation of symbols]

[0035] 1 injection molding machine 2 Mold clamping device 3 Injection device 31 Injection cylinder 32 screws 33 Drive mechanism 41 Front plate 42 Intermediate plate 43 Rear plate 45 Upper connecting member 46 Lower connecting member 47 Guide Rail 61 Support part 62 Base 63, 66 Legs 65 Hollow part 67, 69 Plate-shaped part 68 Through Hole

Claims

1. An injection cylinder; a screw housed in the injection cylinder; a drive mechanism for the screw; a front plate supporting the injection cylinder; a rear plate supporting the drive mechanism; an intermediate plate located between the front plate and the rear plate and rotatably supporting the screw; at least one upper connecting member connecting the front plate and the rear plate; at least one lower connection member located below the at least one upper connection member and connecting the front plate and the rear plate; and the at least one lower connection member supports the intermediate plate so as to be movable in the axial direction of the injection cylinder; the rear plate has a support portion that supports the drive mechanism and is connected to the at least one upper connection member, and a base portion that is connected to the support portion and the at least one lower connection member, and the base portion has lower rigidity in the axial direction than the support portion.

2. The injection device according to claim 1 , wherein the support portion and the base portion form a hollow portion that penetrates in the axial direction.

3. The injection device according to claim 1 , wherein the base portion comprises a base plate and two legs connected to the base plate.

4. 4. The injection device according to claim 3, wherein the average axial dimension of each of the two legs is smaller than the axial thickness of the support at a portion where the legs are connected.

5. 2. The injection device of claim 1, wherein the base portion has only one leg portion.

6. 2. The injection device according to claim 1, wherein the base portion has a plate-like body, and the plate-like body has at least one hollow portion penetrating in the axial direction.

7. The injection device according to claim 1 , wherein the base portion has a plate-like body, and the average thickness of the plate-like body in the axial direction is smaller than the average thickness of the support portion in the axial direction.

8. The injection device according to claim 1 , wherein the at least one lower connection member is one lower connection member, and the one lower connection member includes two guide rails that movably support the intermediate plate.

9. The injection device according to claim 1 , wherein the at least one lower connection member is two lower connection members, and each of the two lower connection members includes a guide rail that movably supports the intermediate plate.

10. 8. The injection device according to claim 1, wherein the at least one upper connecting member is two upper connecting members, and the two upper connecting members are located on both sides of a center line of the injection cylinder when viewed in a vertical direction.

11. The injection device according to claim 1 , wherein the at least one upper connecting member is one upper connecting member.

12. An injection molding machine having an injection unit and a mold clamping unit that fixes and opens and closes a mold, The injection device An injection cylinder; a screw housed in the injection cylinder; a drive mechanism for the screw; a front plate supporting the injection cylinder; a rear plate supporting the drive mechanism; an intermediate plate located between the front plate and the rear plate and rotatably supporting the screw; at least one upper connecting member connecting the front plate and the rear plate; at least one lower connection member located below the at least one upper connection member and connecting the front plate and the rear plate; and the at least one lower connection member supports the intermediate plate so as to be movable in the axial direction of the injection cylinder; the rear plate has a support portion that supports the drive mechanism and is connected to the at least one upper connection member, and a base portion that is connected to the support portion and the at least one lower connection member, and the base portion has lower rigidity in the axial direction than the support portion.

13. The injection molding machine according to claim 12 , wherein the support portion and the base portion form a hollow portion that penetrates in the axial direction.

14. 14. The injection molding machine according to claim 12 or 13, wherein the base portion comprises a base plate and two legs connected to the base plate.

15. 15. The injection molding machine according to claim 14, wherein the average axial dimension of each of the two legs is smaller than the axial thickness of the support at the portion where the legs are connected.

16. 13. The injection molding machine of claim 12, wherein the base portion has only one leg portion.

17. 13. The injection molding machine according to claim 12, wherein the base portion has a plate-like body, and the plate-like body has at least one hollow portion penetrating in the axial direction.

18. The injection molding machine according to claim 12, wherein the base portion has a plate-like body, and the average thickness of the plate-like body in the axial direction is smaller than the average thickness of the support portion in the axial direction.

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