Mold clamping device and injection molding machine

Abstract

A mold clamping device and an injection molding machine are provided, which have a guide mechanism that reliably prevents the movable disc from collapsing. The mold clamping device (2) includes a fixed disc (9), a mold clamping housing (10), and a movable disc (11). The fixed disc (9) is fixed to a base (B), and the mold clamping housing (10) and the movable disc (11) slide on the base (B). The mold clamping housing (10) and the fixed disc (9) are connected by multiple tie rods (13), and the movable disc (11) is penetrated by the tie rods (13). Furthermore, a mold clamping mechanism (15) is provided between the mold clamping housing (10) and the movable disc (11). This disclosure utilizes a linear guide rail (19) that slides relative to the base (B) and a tie rod guide bushing (20) that slides relative to the tie rods (13) to form the sliding mechanism of the movable disc (11).

Description

Technical Field

[0001] The present invention relates to a mold closing device in which a movable disc slides on a base via a linear guide during mold opening and closing, and to an injection molding machine having such a mold closing device. Background Technology

[0002] The mold clamping device of an injection molding machine generally consists of a fixed platen, a mold clamping housing, a movable platen, multiple tie rods, and a mold clamping mechanism. The fixed platen is fixed to the base, and the mold clamping housing and the movable platen are mounted in a manner that allows them to slide freely on the base. Furthermore, the fixed platen and the mold clamping housing are connected by multiple tie rods, through which the movable platen passes. The mold clamping mechanism, including a toggle mechanism and a mold clamping cylinder, is located between the mold clamping housing and the movable platen. Therefore, when the mold clamping device is driven, the movable platen slides on the base to open and close the mold.

[0003] To prevent the movable disk from tilting and thus collapsing, and to ensure precise and smooth sliding, a guiding mechanism is provided. Two types of guiding mechanisms are known: a tie rod guide bushing and a linear guide rail. The tie rod guide bushing is disposed in a through hole in the movable disk through which the tie rod passes, and slides slidably with the tie rod to guide the movable disk. A linear guide rail, as described in Patent Document 1, is disposed between the base and the movable disk. Either type of guiding mechanism is used in the movable disk.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2008-12813 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] Linear guides are highly durable and less prone to failure even during long-term operation, making them an excellent choice. Therefore, they have been frequently used as guiding mechanisms for movable discs in recent years. However, linear guides also carry the risk of movable disc collapse. For example, if a heavy mold is installed, the center of gravity of both the movable disc and the mold may shift towards the mold. This can easily lead to collapse during mold opening and closing, and during mold closing. Alternatively, in cases where the mold closing mechanism consists of a toggle mechanism, the pins connecting the links of the toggle mechanism, and the bushings on these pins, will wear down over time. This wear disrupts the symmetry of the toggle mechanism, causing an imbalance in the forces acting on the movable disc, making it prone to collapse. Linear guides cannot completely prevent collapse once it occurs.

[0009] In this disclosure, a mold closing device and an injection molding machine are provided, which have a guide mechanism capable of reliably preventing the collapse of the movable plate.

[0010] Other issues and novel features will become clear from the description and accompanying drawings in this specification.

[0011] Methods for solving problems

[0012] This disclosure comprises a mold clamping device with features in the guiding mechanism of the movable platen, and an injection molding machine having such a mold clamping device. The mold clamping device includes a fixed platen, a mold clamping housing, and a movable platen. The fixed platen is fixed to a base, and the mold clamping housing and the movable platen slide on the base. The mold clamping housing and the fixed platen are connected by multiple tie rods, through which the movable platen is traversed. Furthermore, a mold clamping mechanism is provided between the mold clamping housing and the movable platen. In this mold clamping device, the sliding mechanism of the movable platen is constituted by a linear guide rail that slides relative to the base and a tie rod guide bushing that slides relative to the tie rods.

[0013] Invention Effects

[0014] This invention enables the stable guidance of the opening and closing of the movable plate over a long period of time and reliably prevents the movable plate from collapsing. Attached Figure Description

[0015] Figure 1 This is a front view showing the injection molding machine of this embodiment.

[0016] Figure 2 This is a front sectional view showing the movable disc and tie rod of the mold clamping device in this embodiment.

[0017] Figure 3 This is a front sectional view showing a portion of the movable disk, the tie rod, and the tie rod guide bushing of the first embodiment.

[0018] Figure 4 This is a front sectional view showing the movable disc and connecting rod of the first embodiment.

[0019] Figure 5 This is a front sectional view showing a conventional movable disc and connecting rod consisting of linear guide rails for the guiding mechanism.

[0020] Figure 6 This is a front sectional view showing the movable disc and connecting rod of the second embodiment.

[0021] Figure 7 This is a front sectional view showing a portion of the movable disk, the tie rod, and the tie rod guide bushing of the third embodiment.

[0022] Figure 8A This is a front sectional view showing a portion of the movable disk, the tie rod, and the tie rod guide bushing of the fourth embodiment.

[0023] Figure 8B It is shown in Figure 8AA side sectional view of a portion of the movable disc, the tie rod, and the tie rod guide bushing of the fourth embodiment when cut at section XX.

[0024] Label Explanation

[0025] 1 Injection molding machine, 2 Mold clamping device, 3 Injection device, 5 Heating cylinder, 6 Hopper, 7 Injection nozzle, 9 Fixed plate, 10 Mold clamping housing, 11 Movable plate, 13 Tie rod, 15 Mold clamping mechanism, 16 Mold, 17 Mold, 19 Linear guide rail, 20 Tie rod guide bushing, 22 Rail, 23 Slider, 24 Guide hole, 26 Inner diameter, 27 Outer diameter, 28 Center of gravity. Detailed Implementation

[0026] The following describes the specific implementation method, referring to the appendix. Figure 1 The following is a detailed description. However, the embodiments described below are not limited to. To make the description clearer, the following description and drawings have been appropriately simplified. In each drawing, the same reference numeral is used to label the same element, and repeated descriptions have been omitted as needed. In addition, some parts have had their shading omitted to avoid making the drawings complicated.

[0027] This implementation method is described below.

[0028] <Injection Molding Machine>

[0029] The injection molding machine 1 in this embodiment is as follows: Figure 1 It is configured as shown. That is, it is roughly configured by the mold clamping device 2 and the injection device 3 of this embodiment, which will be described next. Although in Figure 1 The diagram is simplified, but the injection device 3 consists of a heating cylinder 5 and a screw (not shown) disposed within the heating cylinder 5. The heating cylinder 5 is equipped with a hopper 6 for supplying injection material and an injection nozzle 7.

[0030] <Mold Closing Device>

[0031] The mold clamping device 2 of this embodiment includes a fixed plate 9 fixed to a base B, a mold clamping housing 10 sliding on the base B, and a movable plate 11A of the first embodiment that also slides on the base B. The fixed plate 9 and the mold clamping housing 10 are connected by multiple (e.g., four) connecting rods 13, 13, ... The movable plate 11A is slidably toward the fixed plate 9 through these connecting rods 13, 13, ... A mold clamping mechanism 15 is provided between the mold clamping housing 10 and the movable plate 11A. Furthermore, molds 16 and 17 are respectively provided on the fixed plate 9 and the movable plate 11A. Therefore, if the mold clamping mechanism 15 is driven, the molds 16 and 17 are opened and closed. It should be noted that the mold clamping mechanism 15 can also be composed of a hydraulically driven mold clamping cylinder, and its type is not limited, but a toggle mechanism is used in this embodiment.

[0032] <Guiding mechanism of movable disc>

[0033] In this embodiment, such as Figure 2 As shown, the movable disk 11A is characterized by having two different types of guide mechanisms. This will be explained.

[0034] Linear guide rail

[0035] In the first embodiment, the movable disk 11A is first provided with a linear guide rail 19 as a guiding mechanism. The linear guide rail 19 consists of a rail 22 fixed to the base B and a slider 23 that slides on the rail 22. The slider 23 is fixed to the bottom of the movable disk 11A. Because the movable disk 11A has the linear guide rail 19 as a guiding mechanism, it can slide smoothly on the base B.

[0036] <Tie rod guide bushing>

[0037] In the first embodiment, the movable disk 11A is further provided with rod guide bushings 20, 20, ... as a guiding mechanism. Specifically, in the movable disk 11A, rod guide bushings 20, 20, ... are provided in guide holes 24, 24, ... through which the rods 13, 13, ... pass.

[0038] However, in the first embodiment, there are two further features regarding the tie rod guide bushings 20, 20, ... The first feature is that the tie rod guide bushings 20, 20, ... are only provided on the tie rods 13, 13 located at the upper part and not on the tie rods 13, 13 located at the lower part. This is because, as will be explained later, the effect of preventing the movable disc 11A from collapsing can be sufficiently achieved simply by providing the tie rod guide bushings 20, 20 on the tie rods 13, 13 located at the upper part.

[0039] The second feature concerns the fit tolerances between the tie rod guide bushings 20, 20, ... and the tie rods 13, 13. Figure 3 The diagram shows a rod guide bushing 20 provided in the guide hole 24 of the movable disk 11A, but the inner diameter 26 of the rod guide bushing 20 is larger than the outer diameter 27 of the rod 13 that passes through it.

[0040] Generally, regarding the degree of fit between a shaft and a hole, a fit where the shaft diameter is larger than the hole diameter is called an interference fit, a fit where the shaft diameter and hole diameter are approximately equal is called a transition fit, and a fit where the shaft diameter is smaller than the hole diameter is called a clearance fit. In conventional movable discs where the guiding mechanism consists only of a tie rod guide bushing, a tie rod guide bushing with an easy running fit (clear clearance fit) is used. However, in the first embodiment, tie rod guide bushings 20, 20, ... with a looser fit (loose running fit) are used. Specifically, the tolerance grades for the holes have conventionally used "H7," "H8," etc., indicating an easy running fit. This hole tolerance grade is determined by a so-called shaft reference based on the outer diameter 27 of the tie rod 13. However, in the first embodiment, "D7," "D8," etc., indicating a loose fit, are used. In the case of, for example, “D7”, when the outer diameter 27 of the tie rod 13 is 160 mm, the inner diameter 26 of the tie rod guide bushing 20 is manufactured to be 160.145 mm to 160.185 mm.

[0041] Thus, in the first embodiment, since the guide bushings 20, 20, ... provided on the movable disk 11A have a loose clearance fit relative to the guide rods 13, 13, ..., the sliding load on the guide bushings 20, 20, ... is small. This is because the movable disk 11A is mainly guided by the linear guide rail 19, therefore the frequency of contact between the guide bushings 20, 20, ... and the guide rods 13, 13, ... is low, and their surface pressure P is small. Therefore, even if the movable disk 11A is opened and closed at high speed, the product of the movable disk 11A and the sliding speed V, i.e., the PV value, will not exceed the allowable PV value of the guide bushings 20, 20, ... In other words, this becomes an advantageous structure that enables high-speed mold opening and closing and high-cycle injection molding.

[0042] <Function of the mold closing device in this embodiment>

[0043] Explain the function of the mold clamping device 2 in this embodiment. For example... Figure 4 As shown, a mold 17 is mounted on the movable disk 11A. Therefore, the greater the weight of the mold 17, the more the center of gravity 28 of the movable disk 11A shifts in the direction of arrow 29. The more the center of gravity 28 shifts towards the mold 17, the more the linear guide rail 19... Figure 4 The load is more concentrated on the right side compared to the left side. As a result, the movable disk 11A generates a clockwise torque, making it prone to collapse.

[0044] If the mold closing mechanism 15 is driven to open and close the mold, the movable disk 11A slides as indicated by arrow 30. In the first embodiment, the movable disk 11A is guided not only by the linear guide rail 19 but also by the tie rod guide bushings 20, 20, thus reliably preventing collapse. It should be noted that the collapse of the movable disk 11A can be sufficiently prevented by the tie rod guide bushings 20, 20, which are provided corresponding to the tie rods 13, 13 disposed at the top. Even when the mold is opened and closed at high speed, the movable disk 11A will not collapse but will slide smoothly. Since the collapse of the movable disk 11A is prevented, damage to the linear guide rail 19 is also prevented. It should be noted that by providing the tie rod guide bushings 20, 20, there is also an effect of mitigating the rightward bias of the load acting on the linear guide rail 19.

[0045] <Comparison with previous mold clamping devices>

[0046] exist Figure 5 The diagram shows a conventional movable disk 51 equipped only with a linear guide rail 52 as a guiding mechanism. This movable disk 51 also has connecting rods 53, 53 through it, but connecting rod guide bushings are not provided on the connecting rods 53, 53. The conventional movable disk 51 is used for mold opening and closing with a relatively heavy mold 55. In the case of high-speed mold opening and closing, such as... Figure 5 As shown, the movable plate 51 may collapse. In this case, the linear guide rail 52 will also be damaged. The effect of the mold clamping device 2 of this embodiment cannot be achieved.

[0047] <Modible disc of the second embodiment>

[0048] In the mold clamping device 2 of this embodiment, the movable disk 11A is deformable. As an example of deformation, in... Figure 6 The movable disk 11B of the second embodiment is shown. Like the movable disk 11A of the first embodiment, the movable disk 11B of the second embodiment is provided with two types of guide mechanisms: linear guide rail 19 and tie rod guide bushings 20, 20, ... However, in this second embodiment, the tie rod guide bushings 20, 20, ... are provided corresponding to all the tie rods 13, 13, ... That is, the tie rod guide bushings 20, 20, ... are provided on all the tie rods 13, 13 located at the upper part and all the tie rods 13, 13 located at the lower part. These tie rod guide bushings 20, 20, ... are also loosely clearance-fitted relative to the tie rods 13, 13, ... as in the first embodiment, so they will not wear even during high-speed mold opening and closing.

[0049] <Modible disc of the third embodiment>

[0050] The movable disks 11A and 11B in the first and second embodiments (see reference) Figure 2 , Figure 6 In this process, the guide bushings 20, 20, ... can be deformed. Figure 7 The image shows a movable disk 11C in a third embodiment employing a modified tie rod guide bushing 20C. This tie rod guide bushing 20C forms a clearance fit with the tie rod 13 with a slight rotational engagement. The movable disk 11C in this embodiment can also slide smoothly via two types of guide mechanisms consisting of a linear guide rail 19 and the tie rod guide bushing 20C.

[0051] <The movable disk of the fourth embodiment>

[0052] The movable disks 11A and 11B in the first and second embodiments (see reference) Figure 2 , Figure 6 In this process, the shape of the guide bushings 20, 20, ... can also be deformed. Figure 8A and Figure 8B The image shows a movable disk 11D according to a fourth embodiment, equipped with a guide 20D for a deformed tie rod bushing. The tie rod guide bushing 20D is part of a hollow cylinder with a C-shaped radial cross-section. This tie rod guide bushing 20D is located below the guide hole 24 of the movable disk 11D and is in contact with the lower outer periphery of the tie rod 13. That is, the tie rod guide bushing 20D is substantially in a loose clearance fit relative to the tie rod 13. The movable disk 11D of this fourth embodiment can also slide smoothly via two types of guide mechanisms consisting of a linear guide rail 19 and the tie rod guide bushing 20D.

[0053] While the invention described above is based on specific embodiments, it is not limited to the described embodiments and various modifications are possible without departing from its spirit. The examples described above can also be appropriately combined and implemented.

Claims

1. A mold closing device, It comprises: a fixed plate, fixed to a base; a mold clamping housing, slidably mounted on the base; a movable plate, slidably mounted on the base between the fixed plate and the mold clamping housing; multiple connecting rods connecting the fixed plate and the mold clamping housing and passing through the movable plate; and a mold clamping mechanism disposed between the mold clamping housing and the movable plate, wherein the movable plate is provided with a linear guide rail that slides relative to the base. Only the upper tie rod among the multiple tie rods is provided with a tie rod guide bushing that slides relative to the tie rod.

2. The mold closing device according to claim 1, The inner diameter of the tie rod guide bushing is selected in a way that creates a loose clearance fit relative to the tie rod.

3. The mold clamping device according to claim 1 or 2, The tie rod guide bushing is part of a hollow cylinder with a radial cross-section in the shape of a C, and is connected to the lower outer periphery of the tie rod.

4. An injection molding machine comprising an injection device for injecting resin and a mold closing device for closing a mold, wherein, The mold clamping device includes: a fixed plate fixed to a base; a mold clamping housing slidably disposed on the base; a movable plate slidably disposed on the base between the fixed plate and the mold clamping housing; multiple connecting rods connecting the fixed plate and the mold clamping housing and passing through the movable plate; and a mold clamping mechanism disposed between the mold clamping housing and the movable plate, wherein a linear guide rail is provided on the movable plate to slide relative to the base. Only the upper tie rod among the multiple tie rods is provided with a tie rod guide bushing that slides relative to the tie rod.

5. The injection molding machine according to claim 4, The inner diameter of the tie rod guide bushing is selected in a way that creates a loose clearance fit relative to the tie rod.

6. The injection molding machine according to claim 4 or 5, The tie rod guide bushing is part of a hollow cylinder with a radial cross-section in the shape of a C, and is connected to the lower outer periphery of the tie rod.

Images