Injection device and injection molding machine including the same

Abstract

To reduce the influence of heat on a bearing provided on a front plate.SOLUTION: The injection device includes an injection cylinder 32, a screw 33 built in the injection cylinder 32, a front plate 41 connected to the injection cylinder 32, a moving plate that rotatably supports the screw 33, a ball nut attached to the moving plate, a ball screw 46 that meshes with the ball nut and drives the moving plate in an axial direction of the screw, a bearing 45 that is supported by the front plate 41 and rotatably supports the ball screw 46, and a heat insulating plate 4 that is in contact with the front plate 41 between the injection cylinder 32 and the front plate 41.SELECTED DRAWING: Figure 3

Description

[Technical Field]

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

[0002] An injection unit of an injection molding machine is equipped with a screw drive mechanism. Patent Document 1 describes a drive mechanism that includes a front plate connected to an injection cylinder and a movable plate that rotatably supports the screw. A bearing is provided on the front plate, and a ball screw is rotatably supported by this bearing. A ball nut is attached to the movable plate. Rotation of the ball screw rotates the ball nut, and the movable plate and the screw supported by the movable plate are driven in the axial direction of the screw. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-71233 Summary of the Invention [Problem to be solved by the invention]

[0004] The front plate is connected to the injection cylinder and supports the bearings, so heat from the injection cylinder can be transferred through the front plate to the bearings, potentially affecting their operation.

[0005] An object of the present disclosure is to provide an injection device that can mitigate the influence of heat on a bearing provided in a front plate. [Means for solving the problem]

[0006] The injection device of the present disclosure includes a front plate connected to the injection cylinder, a bearing supported by the front plate, and a heat insulating material in contact with the front plate between the injection cylinder and the front plate. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide an injection device that can mitigate the influence of heat on the bearings provided in the front plate. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic front view of an injection molding machine according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a top view of the injection unit of the injection molding machine shown in FIG. [Figure 3] FIG. 3 is an enlarged view of part A in FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view taken along line AA in FIG. [Figure 5] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following description and drawings, the axial direction of the injection cylinder and screw is referred to as the X direction. The X direction is parallel to the horizontal direction. The direction from the injection unit toward the clamping unit, or the injection direction, is referred to as the +X direction, and the direction from the clamping unit toward the injection unit is referred to as the -X direction. The vertical direction is referred to as the Z direction.

[0010] <Overall structure> Figure 1 shows a schematic front view of an injection molding machine 1 according to one embodiment. Figure 2 shows a top view of the injection unit 3 of the injection molding machine 1 shown in Figure 1. Figure 3 is an enlarged view of part A in Figure 2, showing the front plate and its surrounding structure. The injection molding machine 1 is generally composed of a mold clamping unit 2 that fixes and opens and closes the mold, and an injection unit 3 that heats, melts, and injects the material to be injected.

[0011] <Mold clamping device 2> 1, 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 32, a screw 33 built into the injection cylinder 32, a drive mechanism 34 that drives the screw 33, and a support plate 35 that supports the drive mechanism 34. The drive mechanism 34 drives the screw 33 to rotate and also drives it in the X direction. A hopper 36 that supplies material is connected to the vicinity of the end of the injection cylinder 32 in the -X direction. An injection nozzle 37 that injects material is provided at the tip of the injection cylinder 32 in the +X direction.

[0013] 2 and 3, the injection cylinder 32 has a main body 32A and an injection material supply section 32B provided on the -X direction side of the main body 32A. A hopper 36 is connected to the supply section 32B. The supply section 32B has approximately the same outer shape as the main body 32A and is formed with an internal space through which the screw 33 passes. The screw 33 of the main body 32A is provided with flights 33A for transporting and kneading the material, but the screw 33 of the supply section 32B is not provided with flights 33A.

[0014] <Nozzle touch device 38> 1 and 2, the injection unit 3 is equipped with a nozzle touch device 38. The nozzle touch device 38 connects the support plate 35 and the fixed platen 22. The nozzle touch device 38 is configured, for example, by a mechanism using a hydraulic cylinder or a mechanism using a ball screw. The nozzle touch device 38 drives the support plate 35 in the X direction, causing the injection nozzle 37 to touch the sprue bushing (not shown) of the mold.

[0015] <Drive mechanism 34 of injection unit 3> 2, the drive mechanism 34 for the screw 33 has a front plate 41 that supports the injection cylinder 32, and a movable plate 42 that is located on the −X direction side of the front plate 41. The front plate 41 and the movable plate 42 are supported by a support plate 35. A support portion 39 of the screw 33 is connected to the −X direction end of the screw 33, and the support portion 39 is rotatably supported by the movable plate 42 via a bearing 43. Therefore, the screw 33 is rotatably supported by the movable plate 42 via the support portion 39.

[0016] The drive mechanism 34 has a plasticizing motor 44 provided on the support plate 35 and a rotation transmission mechanism (not shown). The rotation transmission mechanism is composed of a pulley connected to the plasticizing motor 44, a timing belt wound around the pulley, etc. The plasticizing motor 44 rotates the support part 39 via the rotation transmission mechanism, thereby rotating the screw 33.

[0017] The drive mechanism 34 has two ball screws 46 supported on the front plate 41 via bearings 45, an injection motor 47 provided on the support plate 35, and a rotation transmission mechanism 48. The two ball screws 46 are provided on both sides of the central axis CL of the injection cylinder 32 when viewed in the Z direction. The rotation transmission mechanism 48 includes a pulley (not shown) connected to the injection motor 47, a timing belt 49 wound around the pulley, and the like. The timing belt 49 is wound around the pulleys of the two ball screws 46. The injection motor 47 drives the two ball screws 46 to rotate at the same rotational speed via the rotation transmission mechanism 48.

[0018] A ball nut 50 that meshes with the ball screw 46 is attached to the movable plate 42. Because the relative position of the ball screw 46 in the X direction with respect to the front plate 41 is fixed, when the ball screw 46 rotates, the ball nut 50 moves in the X direction along the ball screw 46. As a result, the ball screw 46 drives the movable plate 42 and the screw 33 supported by the movable plate 42 in the X direction. The movable plate 42 is guided by a guide rail 51 provided on the support plate 35, allowing it to move in the X direction.

[0019] The front plate 41 connected to the injection cylinder 32 has a through hole 52 in which a bearing 45 is attached. The bearing 45 supported in the through hole 52 rotatably supports the ball screw 46. There is no limitation on the number of bearings 45, and it is sufficient that at least one bearing 45 is provided. During injection, the injection cylinder 32 receives a reaction force in the -X direction, and this reaction force is transmitted to the front plate 41, pressing the bearing 45 in the -X direction. Therefore, the bearing 45 is a thrust bearing.

[0020] Fig. 4 is a cross-sectional view taken along line AA in Fig. 3. As shown in Figs. 3 and 4, the front plate 41 has a central hole 61 through which the screw 33 passes and a plurality of threaded holes 62 arranged around the central hole 61. A flange 32C is provided at the -X direction end of the supply portion 32B, and the injection cylinder 32 is fixed to the front plate 41 with bolts B1 that pass through holes 32D in the flange 32C and the plurality of threaded holes 62. The cross-sectional area of ​​the surface of the flange 32C perpendicular to the X direction is larger than the cross-sectional area of ​​the surface of the main body portion 32A perpendicular to the X direction.

[0021] Two front cover members 53 are disposed on either side of flange 32C. As shown in FIGS. 3 and 4 , front cover member 53 is fixed to front plate 41 with bolt B2 and covers the end of through hole 52 in the +X direction. The end of through hole 52 in the -X direction is covered by rear cover member 54. Rear cover member 54 is fixed to front plate 41 with bolt B3. Bearing 45 is disposed between front cover member 53 and rear cover member 54 and is pressed in the -X direction by front cover member 53. This applies a preload to bearing 45 in the -X direction.

[0022] <Insulating board 4> As shown in Figures 2 and 3, the heat insulating plate 4 is provided between the injection cylinder 32 and the front plate 41. The heat insulating plate 4 is in contact with the front plate 41 and the supply section 32B. During operation of the injection molding machine 1, the injection cylinder 32 becomes hot, and heat H is transferred from the injection cylinder 32 to the front plate 41 as shown by the dashed line in Figure 3. The heat H can cause thermal deformation of the elements of the bearing 45 (inner ring, outer ring, and balls) and excessive heating of the grease filled inside the bearing 45. In this embodiment, the heat insulating plate 4 limits the transfer of heat H from the injection cylinder 32 to the front plate 41, thereby mitigating the thermal impact on the bearing 45. The material of the heat insulating plate 4 is not limited as long as it has a lower thermal conductivity than the front plate 41 (which is usually made of iron), but examples include resins such as Bakelite and engineering plastics.

[0023] The heat insulating plate 4 can be disposed, for example, between the main body 32A and the supply part 32B. However, the supply part 32B may become hot due to heat from a heater (not shown) in the main body 32A and thermal conduction of the resin inside the injection cylinder 32. In this embodiment, even if the supply part 32B becomes hot, the transfer of heat to the front plate 41 can be limited.

[0024] In addition, the reaction force during injection also acts on the insulating plate 4. However, since the insulating plate 4 generally does not have a high compressive strength, it is preferable to minimize the compressive stress acting on the insulating plate 4. When the insulating plate 4 is installed between the main body 32A and the supply portion 32B, the area of ​​the insulating plate 4 is approximately the same as the cross-sectional area of ​​the injection cylinder 32. In contrast, when the insulating plate 4 is installed so as to contact the flange 32C of the supply portion 32B, it is easy to ensure a larger area. This reduces the compressive stress acting on the insulating plate 4 and suppresses deterioration of the insulating plate 4.

[0025] FIG. 5 shows a front view of the insulating plate 4. The insulating plate 4 is a plate material having the same shape and size as the rear end face of the supply unit 32B in the injection direction (the end face of the flange 32C in the -X direction). The insulating plate 4 may be smaller than the rear end face of the flange 32C in the injection direction, but as mentioned above, it is advantageous for the area of ​​the insulating plate 4 to be as large as possible. Although not shown in FIG. 4, the peripheral portion of the insulating plate 4 in this embodiment has the same shape and size as the peripheral portion of the end face of the flange 32C of the supply unit 32B in the -X direction.

[0026] The heat insulating plate 4 has the same multiple openings as the front plate 41, namely, a central hole 4A through which the screw 33 passes and multiple holes 4B through which the bolts B1 pass. The heat insulating plate 4 is supported on the front plate 41 together with the injection cylinder 32 by the bolts B1. The central hole 4A, the internal space of the supply portion 32B, and the central hole 61 are concentric and have the same diameter. Each of the multiple holes 4B, the hole 32D of the supply portion 32B, and the screw hole 62 are also concentric and have the same diameter. [Explanation of symbols]

[0027] 1 injection molding machine 2 Mold clamping device 3 Injection device 4. Heat insulating board 32 Injection cylinder 32B Supply section 32C flange 33 screw 41 Front plate 42 Moving Plate 45 bearings 46 Ball screw 50 ball nut

Claims

1. An injection cylinder; a screw housed in the injection cylinder; a front plate connected to the injection cylinder; a moving plate that rotatably supports the screw; a ball nut attached to the moving plate; a ball screw that engages with the ball nut and drives the moving plate in the axial direction of the screw; a bearing supported by the front plate and rotatably supporting the ball screw; a heat insulating material in contact with the front plate between the injection cylinder and the front plate; An injection device having:

2. the injection cylinder has a supply portion of injection material located at a rear end in an injection direction; The injection device of claim 1 , wherein the thermal insulation is in contact with the supply portion.

3. 3. The injection device according to claim 2, wherein the supply portion has a flange at a rear end in the injection direction, and the heat insulating material is a plate material having the same shape and size as a rear end face of the flange in the injection direction.

4. An injection molding machine having an injection device and a mold clamping device that supports a mold and opens and closes the mold, The injection device An injection cylinder; a screw housed in the injection cylinder; a front plate connected to the injection cylinder; a moving plate that rotatably supports the screw; a ball nut attached to the moving plate; a ball screw that engages with the ball nut and drives the moving plate in the axial direction of the screw; a bearing supported by the front plate and rotatably supporting the ball screw; a heat insulating material in contact with the front plate between the injection cylinder and the front plate.

5. the injection cylinder has a supply portion of injection material located at a rear end in an injection direction; The injection molding machine according to claim 4 , wherein the heat insulating material is in contact with the supply section.

6. 6. The injection molding machine according to claim 5, wherein the supply section has a flange at a rear end in the injection direction, and the heat insulating material is a plate material having the same shape and size as a rear end face of the flange in the injection direction.

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