Mold clamping device

Abstract

To provide a mold clamping device capable of suppressing the generation of unexpected stress on a mold, even when a single large mold is mounted straddling two mold clamping devices.SOLUTION: A mold clamping device (10) includes a first fixed platen (11A) and a second fixed platen (11B), a first movable platen (13A) corresponding to the first fixed platen (11A) and a second movable platen (13B) corresponding to the second fixed platen (11B), and one or both of a fixed side connector (41) that connects the first fixed platen (11A) and the second fixed platen (11B) and a movable side connector (43) that connects the first movable platen (13A) and the second movable platen (13B).SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a mold clamping device used in a twin injection molding machine in which two injection molding machines are arranged in parallel. [Background technology]

[0002] Patent Document 1 discloses a twin injection molding machine in which two injection molding machines are arranged in parallel and their clamping devices are configured to operate in conjunction with each other through mechanical connection or electrical control, allowing the clamping devices to be selectively used depending on the size of the mold, thereby improving machine operating rates and improving productivity. When the twin injection molding machine of Patent Document 1 uses a large mold that spans the movable platens of two adjacent injection molding machines, the mold is attached to the other movable and fixed platens, and the two clamping devices (first clamping device, second clamping device) are mechanically connected to operate in conjunction with each other. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Publication number 07-46501 Summary of the Invention [Problem to be solved by the invention]

[0004] According to Patent Document 1, the opening and closing operations of the movable platens can be linked, but the fixed platens and the movable platens of two adjacent individual injection molding machines are only connected by having a mold straddle each other. However, when the positions of the fixed platen of the first clamping unit and the fixed platen of the second clamping unit, specifically, the positions of the fixed platen in the mold opening / closing direction perpendicular to the width direction of the fixed platen, do not exactly match during installation, the mold mounting surfaces of the fixed platen of the first clamping unit and the fixed platen of the second clamping unit will be misaligned with respect to the mold mounting surfaces of the adjacent counterparts, resulting in a step. Due to this step, when one large mold is mounted so as to straddle the respective platens, a gap will be generated between the mold and the platen, making the fixation of the mold unstable. In addition, since the mold and the platen are not in close contact in this gap, unexpected bending stress will be generated in the mold during clamping, which may lead to damage or failure of the mold. In addition, the platens are pulled in the width direction (horizontal direction) as they bend during clamping, and the fixed platen of the first clamping unit and the fixed platen of the second clamping unit try to move away from each other, but at this time, because the fixed platen of the first clamping unit and the fixed platen of the second clamping unit are not mechanically connected, the stress lines cannot connect the two platens and flow inside the mold. As a result, the stress lines of the horizontal tensile stress caused by the bending of the platens pass through the mold. In other words, there is a risk that unexpected tensile stress in the width direction will occur in the mold. Based on the above, an object of the present invention is to provide a mold clamping device that can prevent unexpected stress from occurring in a mold even when one large mold is installed across two mold clamping devices. [Means for solving the problem]

[0005] The mold clamping device of the present invention comprises: a first stationary platen and a second stationary platen; a first movable platen corresponding to the first fixed platen and a second movable platen corresponding to the second fixed platen; a fixed side connector that connects the first fixed platen and the second fixed platen; and The actuator is provided with one or both of a movable side connector that connects the first movable platen and the second movable platen.

[0006] In the mold clamping device, preferably, the first stationary platen has a first opposing surface and the second stationary platen has a second opposing surface; The first movable platen has a third opposed surface opposing the first opposed surface, and the second movable platen has a fourth opposed surface opposing the second opposed surface. A preferred clamping device is a fixed side connector that spans the first opposing surface and the second opposing surface and connects the first fixed platen and the second fixed platen; and The movable platen has one or both of a movable side connector that spans the third opposing surface and the fourth opposing surface and connects the first movable platen and the second movable platen.

[0007] In a preferred clamping device, The fixed side connector is It is detachably fixed to the first and second fixed plates, The movable connecting body is It is detachably fixed to the first movable platen and the second movable platen.

[0008] In the mold clamping device, preferably, a fixed-side intermediate body provided between the fixed-side connecting body and the first and second fixed plates; The movable side intermediate body is provided between the movable side connector and the first and second movable platens.

[0009] The fixed intermediate body is preferably The fixed side connector is slidable relative to the first fixed plate and the second fixed plate, or The rigidity is lower than that of the fixed side connecting body, the first fixed platen, and the second fixed platen, The movable intermediate body is preferably The movable connector is slidable relative to the first movable platen and the second movable platen, or The rigidity is lower than that of the movable side connector, the first movable platen, and the second movable platen. Effect of the Invention

[0010] According to the present invention, the fixed-side connector and / or the movable-side connector are provided, and even if one large mold is mounted across two mold clamping units, the occurrence of unexpected stress in the mold can be suppressed. [Brief description of the drawings]

[0011] [Figure 1] 1 is a plan sectional view showing a basic configuration of an injection molding machine to which the present invention is applied. [Diagram 2] FIG. 1 is a plan sectional view showing a mold clamping device according to a first embodiment. [Diagram 3] 3 is a view of the opposing surface of the mold clamping unit in FIG. 2. [Figure 4] 5A to 5C are diagrams illustrating the effects of the mold clamping device according to the first embodiment. [Diagram 5] FIG. 11 is a cross-sectional plan view showing a mold clamping device according to a second embodiment before mold clamping. [Figure 6] FIG. 11 is a cross-sectional plan view showing a clamping state of the clamping device according to the second embodiment. [Figure 7] FIG. 11 is a cross-sectional plan view of a mold clamping device according to a third embodiment. [Figure 8] FIG. 11 is a cross-sectional plan view showing a mold clamping device according to a fourth embodiment. [Figure 9] FIG. 13 is a cross-sectional plan view showing a mold clamping device according to a fifth embodiment before mold clamping. [Figure 10] FIG. 13 is a cross-sectional plan view showing a clamping state of a clamping device according to a fifth embodiment. [Figure 11] 1A and 1B are diagrams illustrating a stress state of a mold clamping unit according to a basic configuration. [Figure 12] 1A and 1B are diagrams illustrating a clamping state of a clamping device according to a basic configuration. [Figure 13] 13A and 13B are diagrams showing modified examples of the fixed side connector (movable side connector). [Figure 14] FIG. 13 is a diagram showing an example of the arrangement of a fixed side connector (a movable side connector). DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, a basic configuration applied to this embodiment will be described first, and then a more specific embodiment will be described.

[0013] [Basic configuration: See Figure 1] An injection molding machine 100 having a basic configuration includes a clamping device 10 and an injection device 30 that injects molten resin into one mold 50 clamped by the clamping device 10. The clamping devices 10 in the injection molding machine 100 clamp one mold 50 with two clamping devices 10. The horizontal direction H and vertical direction V are defined as shown in Fig. 1, and the length direction L and width direction W of the injection molding machine 100 are defined as shown in Fig. 1.

[0014] [Clamping device 10: see Figure 1] In the mold clamping unit 10, a first mold clamping unit 10A and a second mold clamping unit 10B are arranged in parallel in the horizontal direction H. The first mold clamping unit 10A and the second mold clamping unit 10B are arranged differently, but have the same configuration including dimensions. Therefore, the configuration of the first mold clamping unit 10A will be described below, but for the second mold clamping unit 10B, the same components as those of the first mold clamping unit 10A will be given the same reference numerals and descriptions thereof will be omitted.

[0015] The first mold clamping unit 10A includes a first fixed platen 11A on which the fixed mold 51 is supported, and a first movable platen 13A on which the movable mold 53 is supported. The second mold clamping unit 10B includes a second fixed platen 11B on which the fixed mold 51 is supported, and a second movable platen 13B on which the movable mold 53 is supported. The first fixed platen 11A and the second fixed platen 11B are installed on a base (not shown) and their positions are fixed, whereas the first movable platen 13A and the second movable platen 13B are supported, for example, by a guide rail laid on the base so as to be movable forward (F) and backward (R).

[0016] The first clamping device 10A includes a clamping hydraulic chamber 18 for applying a load for clamping the mold 50 via the first fixed platen 11A and the first movable platen 13A. The clamping hydraulic chamber 18 is provided at the four corners of the first fixed platen 11A when viewed from the front. The clamping hydraulic chamber 18 accommodates the ram 16 provided at the front (F) end of the tie bar 17 inside, so that the clamping side chamber 18A is disposed at the rear (R) and the mold opening side chamber 18B is disposed at the front (F) of the ram 16. A hydraulic source (not shown) is connected to the clamping side chamber 18A and the mold opening side chamber 18B, and hydraulic oil is supplied to the clamping side chamber 18A when clamping the mold, and hydraulic oil is supplied to the mold opening side chamber 18B when opening the mold.

[0017] The ram 16 is movable forward and backward in the clamping hydraulic chamber 18, and the tie bar 17 is connected to one side of the tie bar 16. The tie bar 17 penetrates the first movable platen 13A, and a plurality of ring grooves (male threads) with equal or unequal pitches (not shown) are formed at the rear (R) end of the tie bar 17. A split nut 19 having a ring-shaped inner groove (female thread) that meshes with the ring groove (male thread) of the tie bar 17 is provided at the rear (R) end face of the first movable platen 13A. When hydraulic oil is supplied to the clamping side chamber 18A, the hydraulic oil in the clamping side chamber 18A pushes the ram 16 forward (F), so that the tie bar 17 receives a tensile load in the forward (F) direction. The split nut 19 is provided at the rear (R) of the first movable platen 13A, so that the first movable platen 13A receives a tensile load in the forward (F) direction generated on the tie bar 17 through the split nut 19 engaged with the tie bar 17. In this manner, the movable mold 53 is pressed against the fixed mold 51 to perform mold clamping.

[0018] The above-mentioned configuration and clamping operation of the first clamping unit 10A also apply to the second clamping unit 10B.

[0019] [Injection unit 30: see Figure 1] After the mold clamping is completed, the injection molding machine 100 injects molten resin into a cavity formed between the fixed mold 51 and the movable mold 53 to form a molded product. The injection molding machine 100 is provided with an injection unit 30 for this purpose, but here only two injection barrels 31 that inject the molten resin are drawn apart from the first mold clamping unit 10A and the second mold clamping unit 10B.

[0020] [Mold 50: See Figure 1] The mold 50 includes a fixed mold 51 and a movable mold 53 . The fixed mold 51 is supported by the first fixed platen 11A of the first mold clamping unit 10A and the second fixed platen 11B of the second mold clamping unit 10B. Moreover, the movable mold 53 is supported by the first movable platen 13A of the first mold clamping unit 10A and the second movable platen 13B of the second mold clamping unit 10B. That is, the fixed mold 51 is supported across the first fixed platen 11A and the second fixed platen 11B, and the movable mold 53 is supported across the first movable platen 13A and the second movable platen 13B. Moreover, one mold 50 is supported by two units, the first mold clamping unit 10A and the second mold clamping unit 10B. The fixed die 51 and the movable die 53 are made of a steel material called a steel for plastic dies. Specifically, pre-hardened steels such as JIS SC series, SCM series, and SKD61, quenched and tempered steels such as JIS SKD11 and 12, stainless steels such as JIS SUS420J2 and SUS630, and maraging steels are used as the steel for plastic dies. In addition, the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A and the second movable platen 13B are generally made of cast iron such as spheroidal graphite cast iron or gray cast iron, but the same steel material as the fixed mold 51 and the movable mold 53 may also be used.

[0021] [First embodiment: see Figs. 2 and 3] The mold clamping apparatus 10-1 according to the first embodiment includes a mold connecting body 40 while following the mold clamping apparatus 10 according to the basic configuration. The mold connecting body 40 includes a fixed side connecting body 41 provided on the side of the first fixed platen 11A and the second fixed platen 11B, and a movable side connecting body 43 provided on the side of the first movable platen 13A and the second movable platen 13B. The fixed side connecting body 41 is fixed across the first opposing surface 11C of the first fixed platen 11A with the first movable platen 13A and the second opposing surface 11D of the second movable platen 13B of the second fixed platen 11B. The movable side connecting body 43 is fixed across the third opposing surface 13C of the first fixed platen 11A with the first movable platen 13A and the fourth opposing surface 13D of the second movable platen 13B. The fixed side connecting body 41 covers the first opposing surface 11C and the second opposing surface 11D except for the tie bar 17 portion. The movable side connecting body 43 covers the third opposing surface 13C and the fourth opposing surface 13D except for the tie bar 17 portion. The fixed side connector 41 and the movable side connector 43 are fixed to the first fixed platen 11A, the second fixed platen 11B and the first movable platen 13A, the second movable platen 13B by fasteners 49, respectively.

[0022] In this embodiment, there may be cases where a large mold that spans two units, the first mold clamping unit 10A and the second mold clamping unit 10B, is not used. In this case, the first opposing surface 11C and the second opposing surface 11D may be capable of mounting individual molds with the fixed side connector 41 removed, and the third opposing surface 13C and the fourth opposing surface 13D may be capable of mounting individual molds with the movable side connector 43 removed. This allows the two units, the first mold clamping unit 10A and the second mold clamping unit 10B, to operate independently of each other and perform molding operations with individual molds. In this case, the fixing means for fixing the fixed side connector 41 and the movable side connector 43 to the first fixed platen 11A and the second fixed platen 11B and the first movable platen 13A and the second movable platen 13B, respectively, is preferably a fixing means for removably fixing the fixed side connector 41 and the movable side connector 43 to the first fixed platen 11A and the second fixed platen 11B and the first movable platen 13A and the second movable platen 13B, respectively. In this case, the first opposing surface 11C and the second opposing surface 11D are preferably subjected to positioning processing for easy attachment and detachment of the fixed side connector 41, and the third opposing surface 13C and the fourth opposing surface 13D are preferably subjected to positioning processing for easy attachment and detachment of the movable side connector 43. In this case, the positioning processing may be a positioning pin processing or a groove processing that allows precise fitting.

[0023] The fixed mold 51 of the mold 50 is fixed to the first fixed platen 11A and the second fixed platen 11B by an appropriate means via the fixed side connector 41. The movable mold 53 of the mold 50 is fixed to the first movable platen 13A and the second movable platen 13B by an appropriate means via the movable side connector 43. The fixed mold 51 and the movable mold 53 are attached to the fixed side connector 41 and the movable side connector 43 so that they are positioned to coincide with each other. In this way, the fixed side connector 41 and the movable side connector 43 can be called the fixed side attachment body and the movable side attachment body, since the fixed mold 51 and the movable mold 53 are attached to them, respectively.

[0024] The fixed side connector 41 and the movable side connector 43 may be made of cast iron like the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A and the second movable platen 13B, or may be made of steel like the fixed die 51 and the movable die 53. However, in order to reduce the weight including the first fixed platen 11A to the second movable platen 13B, it is preferable that the fixed side connector 41 and the movable side connector 43 are made thinner and lighter than the first fixed platen 11A to the second movable platen 13B.

[0025] [Effects of the first embodiment (connected mold body): see Figs. 4, 11 and 12] The effect of providing the mold connector 40 when hydraulic oil is supplied to the mold clamping side chamber 18A of the mold clamping hydraulic chamber 18 to clamp the fixed mold 51 and the movable mold 53 will be described.

[0026] <Stress state in the first embodiment: Figs. 4 and 11> When the mold is clamped, a tensile stress is generated in each tie bar 17 in its axial direction, and the ends of the first fixed platen 11A and the first movable platen 13A in the width direction W, which are not sandwiched with the mold 50 and are not backed up by the mold 50, bend toward each other, and the ends of the second fixed platen 11B and the second movable platen 13B in the width direction W also bend toward each other. Due to this bending, the first fixed platen 11A and the second fixed platen 11B, and the first movable platen 13A and the second movable platen 13B are pulled in the direction separating them (the width direction W), so that a tensile stress σi is generated inside the first fixed platen 11A and the second fixed platen 11B, and the first movable platen 13A and the second movable platen 13B (FIG. 11). The stress line Lσ due to the tensile stress σi is shown in Figure 4. However, since the first fixed platen 11A and the second fixed platen 11B, and the first movable platen 13A and the second movable platen 13B are not directly connected to each other, the stress line Lσ passes through the fixed side connector 41 and the movable side connector 43, i.e., the inside of the mold connector 40, at the adjacent portions of the first fixed platen 11A and the second fixed platen 11B, and the first movable platen 13A and the second movable platen 13B.

[0027] <Stress state in basic configuration: Figure 11> Here, the stress line Lσ when the mold clamping device 10 according to the basic configuration not including the mold connecting body 40 is clamped is as shown in FIG. 11. That is, since the first fixed platen 11A and the second fixed platen 11B are not connected and there is a gap G1, the stress line Lσ cannot directly communicate from the first fixed platen 11A to the second fixed platen 11B and passes through the inside of the fixed mold 51. Normally, a mold is not designed assuming that tensile stress acts in the width direction, so there is a risk that tensile stress in an unexpected direction will be generated in the fixed mold 51. If injection molding is repeatedly performed using the fixed mold 51, the possibility that the fixed mold 51 will become fatigued and break cannot be denied. In contrast, if the mold connecting body 40 is provided, the stress line Lσ passes through the mold connecting body 40, so that unexpected stress will not be generated in the fixed mold 51. The same is true for the movable mold 53.

[0028] <Positional deviation in basic configuration: Figure 12> Another concern regarding the mold clamping device 10 related to the basic configuration will be described with reference to FIG. The concern is that the position of the first fixed platen 11A of the first clamping device 10A and the position of the second fixed platen 11B of the second clamping device 10B do not match, resulting in a positional deviation G2. When this positional deviation G2 occurs, a positional deviation also occurs between the first opposing surface 11C of the first fixed platen 11A and the second opposing surface 11D of the second fixed platen 11B. In this case, a gap G3 occurs between the fixed mold 51 and the second fixed platen 11B, making the fixation of the fixed mold 51 unstable. Alternatively, an unexpected bend occurs in the fixed mold 51 during mold clamping, which may lead to damage or failure of the fixed mold 51.

[0029] In response to this, by providing the mold connecting body 40, the positions of the first fixed platen 11A and the second fixed platen 11B are corrected, and the occurrence of the positional deviation G2 and the gap G3 can be prevented. The fixed side connector 41 and the movable side connector 43 are fixed to the first fixed platen 11A and the second fixed platen 11B and the first movable platen 13A and the second movable platen 13B by fasteners 49, respectively. At this time, it is preferable to fix the mold connector 40 to the first fixed platen 11A and the second fixed platen 11B, respectively, and integrate the mold connector 40, the first fixed platen 11A and the second fixed platen 11B, and then fix the first fixed platen 11A and the second fixed platen 11B to the base. This allows the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A and the second movable platen 13B to be fixed respectively based on the mold connector 40, which makes it easy to fix the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A and the second movable platen 13B to the base without causing misalignment G2 and gap G3.

[0030] In this case, there is a preferable arrangement of the fixed side connector 41 and the movable side connector 43 when the fixed side connector 41 is fixed to the first fixed platen 11A and the second fixed platen 11B and the movable side connector 43 is fixed to the first movable platen 13A and the second movable platen 13B. That is, as shown in Figures 14(a) and 14(b), it is preferable that the end edges E on both sides in the width direction W of the fixed side connector 41 and the movable side connector 43 exceed the center line CV extending in the vertical direction V of the first fixed platen 11A to the second movable platen 13B. Here, the centers of gravity of the first fixed platen 11A to the second movable platen 13B are on the center line CV, and the first fixed platen 11A to the second movable platen 13B tend to rotate around the center line CV. For example, as shown in FIG. 14(c), if the edge E on one side in the width direction W does not cross the center line CV, the second fixed platen 13A and the second movable platen 13B tend to rotate around the center line CV. However, as shown in FIG. 14(a) and (b), if the edges E on both sides in the width direction W of the fixed side connector 41 and the movable side connector 43 are in the hatched region crossing the center line CV, the positions of the centers of gravity of the first fixed platen 11A to the second movable platen 13B, which tend to become the center of rotation, can be accommodated within the fixed region by the fixed side connector 41 and the movable side connector 43. This makes it difficult for the first fixed platen 11A to the second movable platen 13B to rotate relative to the fixed side connector 41 and the movable side connector 43, which is effective in preventing the fixed side connector 41 and the movable side connector 43 from tilting relative to the fixed side connector 41 and the movable side connector 43.

[0031] This also allows the first movable platen 13A and the second movable platen 13B to be connected without being tilted to each other. This makes the directions of the clamping force between the first fixed platen 11A and the second fixed platen 11B, and between the first movable platen 13A and the second movable platen 13B, which are directly applied with the clamping force during clamping, the same (parallel), and prevents unexpected bending deformation from occurring in the fixed side connector 41, the movable side connector 43, the fixed mold 51, and the movable mold 53. In this case, it is further preferable that the first fixed platen 11A and the second fixed platen 11B are fixed on the same surface of the fixed side connector 41 so as to be in close contact with each other over almost the entire surfaces of the first opposing surface 11C and the second opposing surface 11D.

[0032] Moreover, it is preferable that the fixed side connector 41 and the movable side connector 43 are each a single plate-like member that covers the areas of the first opposing surface 11C and the second opposing surface 11D and the third opposing surface 13C and the fourth opposing surface 13D where the mold is attached. This allows the attachment surface to be a flat surface without steps, even if the mold is large enough that the mold end comes close to the tie bar 17 when the mold is attached. This makes it possible to prevent localized dents (destruction) caused by pressing a step against the attachment surface on the mold side.

[0033] [Second embodiment: see Figs. 5 and 6] Next, a mold clamping device 10-2 according to a second embodiment will be described. In the mold clamping unit 10-2, a fixed side intermediate body 45 is provided between the fixed side connector 41 and the first fixed platen 11A and the second fixed platen 11B, and a movable side intermediate body 47 is provided between the movable side connector 43 and the first movable platen 13A and the second movable platen 13B. In other words, the fixed mold 51 is attached to the first fixed platen 11A and the second fixed platen 11B via the fixed side connector 41 and the fixed side intermediate body 45, and the movable mold 53 is attached to the first movable platen 13A and the second movable platen 13B via the movable side connector 43 and the movable side intermediate body 47.

[0034] The fixed-side intermediate body 45 and the movable-side intermediate body 47 are capable of sliding against each other on their surfaces in contact with the fixed-side connecting body 41 and the movable-side connecting body 43. In addition, the fixed-side intermediate body 45 and the movable-side intermediate body 47 are capable of sliding against each other on their surfaces in contact with the first fixed platen 11A and the second fixed platen 11B, and the first movable platen 13A and the second movable platen 13B.

[0035] In order to achieve the above-mentioned functions, the fixed-side intermediate body 45 and the movable-side intermediate body 47 are preferably made of high-carbon steel such as carbon tool steel or alloy tool steel, which has high hardness and is easy to machine to have a smooth surface. Furthermore, it is preferable to apply a high-sliding surface treatment such as chrome plating or vapor deposition.

[0036] Since the fixed-side intermediate body 45 and the movable-side intermediate body 47 have the above-mentioned sliding performance, as shown in Fig. 6, a tensile stress σi is generated in the first fixed platen 11A and the second fixed platen 11B and the first movable platen 13A and the second movable platen 13B, and the first fixed platen 11A and the second fixed platen 11B and the first movable platen 13A and the second movable platen 13B are pulled in the direction of moving away from each other. Even so, slippage occurs on the surfaces where the fixed-side intermediate body 45 and the movable-side intermediate body 47 contact the fixed-side connector 41 and the movable-side connector 43. In addition, slippage occurs on the surfaces where the fixed-side intermediate body 45 and the movable-side intermediate body 47 contact the first fixed platen 11A and the second fixed platen 11B and the first movable platen 13A and the second movable platen 13B contact each other. These slippages release some or all of the tensile stress σi, preventing the first fixed platen 11A and the second fixed platen 11B and the first movable platen 13A and the second movable platen 13B from transmitting the stretching force associated with the tensile stress σi to the mold 50 via the mold connecting body 40.

[0037] Furthermore, the fixed-side intermediate body 45 may be more easily deformed between the fixed-side connector 41 and the first fixed platen 11A and the second fixed platen 11B than the fixed-side connector 41 and the first fixed platen 11A and the second fixed platen 11B. Furthermore, the movable-side intermediate body 47 may be more easily deformed between the movable-side connector 43 and the first movable platen 13A and the second movable platen 13B than the movable-side connector 43 and the first movable platen 13A and the second movable platen 13B.

[0038] According to this, the fixed-side intermediate body 45 is preferably made of a material or an elastic body having a lower rigidity than any of the fixed-side connecting body 41, the first fixed platen 11A, and the second fixed platen 11B, and the movable-side intermediate body 47 is preferably made of a material or an elastic body having a lower rigidity than any of the movable-side connecting body 43, the first movable platen 13A, and the second movable platen 13B. As the material with low rigidity, for example, a low-hardness metal material such as aluminum or copper having an elastic modulus lower than that of cast iron or carbon steel may be used, and rubber or a spring material may be used as the elastic body.

[0039] If the fixed-side intermediate body 45 has the above-mentioned easy deformability, the difference in the amount of deformation between the fixed-side connecting body 41 and the first fixed platen 11A and the second fixed platen 11B can be absorbed by the deformation of the fixed-side intermediate body 45. Also, if the fixed-side intermediate body 47 has the above-mentioned easy deformability, the difference in the amount of deformation between the movable-side connecting body 43 and the first movable platen 13A and the second movable platen 13B can be absorbed by the deformation of the movable-side intermediate body 47. These deformations release a part or all of the tensile stress σi, and it is possible to prevent the stretching force associated with the tensile stress σi of the first fixed platen 11A and the second fixed platen 11B and the first movable platen 13A and the second movable platen 13B from being transmitted to the mold 50 via the mold connecting body 40.

[0040] [Third and fourth embodiments: Figs. 7 and 8] In this embodiment, other elements can be added to the mold clamping unit 10-1, or some elements can be replaced with other elements. As an example, a third embodiment (mold clamping unit 10-3, FIG. 7) and a fourth embodiment (mold clamping unit 10-4, FIG. 8) will be described. Note that, although mold clamping unit 10-3 and mold clamping unit 10-4 that utilize mold clamping unit 10-1 will be described here, mold clamping unit 10-2 can also be utilized.

[0041] [Clamping device 10-3: see Figure 7] The mold clamping unit 10-3 includes tie bar support plates 21A and 21B that support the tie bars 17 and are spaced apart from the first movable platen 13A and the second movable platen 13B at a position rearward (R) from the first movable platen 13A and the second movable platen 13B. The tie bar support plates 21A and 21B are placed on a base on which the first fixed platen 11A and the second fixed platen 11B, etc. are placed so as to be movable forward and backward.

[0042] The tie bar support plate 21A is provided corresponding to the first movable platen 13A and supports the four tie bars 17 penetrating the first movable platen 13A. A fixing nut 22 is fitted to each of the tie bars 17 penetrating the tie bar support plate 21A, and the tie bar support plate 21A and the tie bars 17 are connected and fixed to each other so that the tie bars 17 do not sag under their own weight. The tie bar support plate 21B is provided corresponding to the second movable platen 13B and supports the four tie bars 17 penetrating the second movable platen 13B. A fixing nut 22 is fitted to each of the tie bars 17 penetrating the tie bar support plate 21B, and the tie bar support plate 21B and the tie bars 17 are connected and fixed to each other so that the tie bars 17 do not sag under their own weight. Incidentally, since the main role of tie bar support plate 21A and tie bar support plate 21B is to support tie bar 17 so that it does not sag under its own weight, tie bar support plate 21A and tie bar support plate 21B do not need to be fixedly connected, but rather may be simply fitted together with a length sufficient to prevent them from falling out of tie bar support plate 21A and tie bar support plate 21B when ram 16 operates.

[0043] When the fixed mold 51 and the movable mold 53 are separated to perform the mold opening operation, the tie bars 17 are released from the split nuts 19, and the first movable platen 13A and the second movable platen 13B are moved backward. At this time, the tie bar support plates 21A and 21B each support four tie bars 17. When the first movable platen 13A and the second movable platen 13B are moved forward to perform the mold closing operation, the tie bar support plates 21A and 21B each support four tie bars 17.

[0044] [Clamping device 10-4: see Figure 8] Next, the mold clamping unit 10-4 transmits the output of the drive source to the first movable platen 13A and the second movable platen 13B via the first toggle link mechanism 25A and the second toggle link mechanism 25B, and moves the first movable platen 13A and the second movable platen 13B forward and backward. That is, the mold clamping unit 10-1 moves the first movable platen 13A and the second movable platen 13B forward and backward by the output of the hydraulic cylinders provided on the first fixed platen 11A and the second fixed platen 11B, but the mold clamping unit 10-4 does not include hydraulic cylinders on the first fixed platen 11A and the second fixed platen 11B. The mold clamping unit 10-4 includes a first support platen 23A and a second support platen 23B for supporting the first toggle link mechanism 25A and the second toggle link mechanism 25B between the first movable platen 13A and the second movable platen 13B. The first support platen 23A and the second support platen 23B are fixed in position relative to the first fixed platen 11A and the second fixed platen 11B, respectively, via tie bars 17. Any drive source can be used for extending and retracting the first toggle link mechanism 25A and the second toggle link mechanism 25B. For example, an electric motor can be used with a mechanism for converting the rotational motion of the electric motor into linear motion interposed therebetween. Also, instead of using the linear motion driven by the electric motor, the first toggle link mechanism 25A and the second toggle link mechanism 25B may be driven by the extension motion of a hydraulic actuator.

[0045] The first toggle link mechanism 25A corresponds to the first mold clamping unit 10A and is provided between the first movable platen 13A and the first support platen 23A. The second toggle link mechanism 25B corresponds to the second mold clamping unit 10B and is provided between the second movable platen 13B and the second support platen 23B. In correspondence with the provision of the first support platen 23A and the second support platen 23B, four tie bars 17 each penetrate the first support platen 23A and the second support platen 23B. A fixing nut 22 is fitted to each of the tie bars 17 penetrating the first support platen 23A, which connects and fixes the first support platen 23A and the tie bars 17, respectively, and restricts the movement of the first support platen 23A to the rear (R). In addition, a fixing nut 22 is fitted onto each of the four tie bars 17 that penetrate the second support plate 23B, which connects and fixes the second support plate 23B and the tie bars 17, and restricts the movement of the second support plate 23B to the rear (R).

[0046] In the mold clamping unit 10-4, four tie bars 17 pass through the first fixed platen 11A and the second fixed platen 11B, and fixing nuts 27 are fitted to the tie bars 17. Therefore, the first fixed platen 11A and the second fixed platen 11B are restricted from moving forward (F). The relative positions of the first fixed platen 11A and the first support platen 23A and the relative positions of the second fixed platen 11B and the second support platen 23B are fixed via the tie bars 17.

[0047] When clamping the fixed mold 51 and the movable mold 53, the first toggle link mechanism 25A and the second toggle link mechanism 25B are extended. Since the relative positions of the first fixed platen 11A and the second fixed platen 11B, and the first support platen 23A and the second support platen 23B are fixed, the fixed mold 51 and the movable mold 53 are pressed against each other.

[0048] In the example described above, the movable side connector 43 is provided on the first movable platen 13A and the second movable platen 13B side as well, but this may be omitted. Generally, in the clamping unit 10-4 using a toggle link mechanism, the toggle link mechanism may be attached near the center of the movable platen. In this case, the clamping force applied to the movable platen is applied to the approximate center in the width direction W, so that the deflection in the clamping direction near the four corners of the movable platen is small, and the deflection of the ends of the platen in the width direction W caused by the deflection of the platen in the clamping direction is small. Since the deflection of the ends of the platen in the width direction W is small, the tensile stress σi in the width direction W is also small, so that there may be cases where there is no problem even if the stress line Lσ flows into the inside of the mold. This also applies to a direct pressure type clamping mechanism using a hydraulic cylinder. As described above, the fixed connector 41 is more essential than the movable connector 43 .

[0049] Although application examples of the mold clamping device 10-1 have been described above, the mold clamping device 10-1 of the present invention can further include other elements that are applicable to injection molding, or can be replaced with other elements.

[0050] [Fifth embodiment: see Figs. 9 and 10] In the clamping unit 10-5 according to the fifth embodiment, the shapes of the fixed side connector 41 and the movable side connector 43 are changed. That is, as shown in Fig. 9, at the end of the fixed side connector 41 in the width direction W and the end of the movable side connector 43 in the width direction W, the surfaces in contact with the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A, and the second movable platen 13B are thinned by thinning 29. As a result, in the corresponding portions, a gap is formed between the fixed side connector 41 and the movable side connector 43 and the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A, and the second movable platen 13B, which is larger at the end side than at the center side of the platen.

[0051] When the fixed mold 51 and the movable mold 53 are clamped, the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A, and the second movable platen 13B are bent. However, at the ends of the fixed side connector 41 and the movable side connector 43 corresponding to the portions of the first movable platen 13A and the second movable platen 13B where the amount of bending is the largest, the surfaces in contact with the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A, and the second movable platen 13B are thinned 29, and gaps are provided between the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A, and the second movable platen 13B and the fixed side connector 41 and the movable side connector 43. This gap absorbs the deflection at the ends of the first movable platen 13A and the second movable platen 13B, so that the fixed side connector 41 and the movable side connector 43 are not subjected to a load due to the deflection of the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A and the second movable platen 13B, or if they are subjected to a load, the load can be kept small. Therefore, the effect of the deflection of the platen on the die can be suppressed.

[0052] Here, an example is shown in which the reduced thickness 29 is provided on the fixed side connecting body 41 and the movable side connecting body 43 side, but the same effect can be obtained by providing reduced thickness at locations corresponding to the reduced thickness 29 on the first fixed platen 11A, the second fixed platen 11B, the first movable platen 13A and the second movable platen 13B.

[0053] In addition to the above, the configurations given in the above embodiments can be selected or appropriately changed to other configurations without departing from the spirit of the present invention. While the fixed side connector 41 and the movable side connector 43 have been exemplified as preferred embodiments, the present invention is not limited thereto, and the embodiment exemplified in Fig. 13 may be adopted. Note that Fig. 13 shows the first fixed platen 11A and the second fixed platen 11B, but the following embodiment may also be adopted for the first movable platen 13 and the second movable platen 13B.

[0054] 13(a) shows an example in which a fixed side connector 41A is provided in a limited area spanning the first fixed platen 11A and the second fixed platen 11B to connect the first fixed platen 11A and the second fixed platen 11B. In this case, dummies 42, 42 are provided on both sides of the fixed side connector 41A to form a flush surface for mounting the fixed mold 51. FIG. 13(b) shows an example in which a fixed side connector 41B is provided on the surface behind the surface on which the fixed mold 51 is attached, to connect the first fixed platen 11A and the second fixed platen 11B. FIG. 13(c) shows an example in which a fixed side connector 41C is provided between the first fixed platen 11A and the second fixed platen 11B to connect the first fixed platen 11A and the second fixed platen 11B. FIG. 13(d) shows an example in which a fixed side connector 41C is provided on the upper surfaces of the first fixed platen 11A and the second fixed platen 11B to connect the first fixed platen 11A and the second fixed platen 11B. As described above, the connector of the present invention includes connecting any portion between two fixed plates that are made separately, or connecting any portion between two movable plates that are made separately. [Explanation of symbols]

[0055] 1,100 Injection molding machine 10,10-1,10-2,10-3,10-4,10-5 Mold clamping device 10A 1st mold clamping device 10B 2nd mold clamping device 11A 1st fixed plate 11B 2nd fixed plate 11C 1st facing surface 11D Second opposing surface 13A 1st movable plate 13B 2nd movable board 13C 3rd facing surface 13D 4th opposing surface 16 Ram 17 Tie bar 19 Split nut 18 Clamping hydraulic chamber 18A Clamping chamber 18B type open side chamber 21A,21B Tie bar support board 22,27 Fixing nut 30 Injection device 31 Ejection Barrel 40 Mold connection body 41 Fixed side connection body 43 Movable side connection body 45 Fixed side intermediate body 47 Movable intermediate body 50 Mold 51 Fixed mold 53 Movable mold

Claims

1. a first stationary platen and a second stationary platen; a first movable platen corresponding to the first fixed platen and a second movable platen corresponding to the second fixed platen; a fixed side connector that connects the first fixed platen and the second fixed platen; and A mold clamping device comprising one or both of a movable side connector that connects the first movable platen and the second movable platen.

2. the first stationary platen has a first opposing surface and the second stationary platen has a second opposing surface; the first movable platen has a third opposing surface facing the first opposing surface, and the second movable platen has a fourth opposing surface facing the second opposing surface; a fixed side connector that spans the first opposing surface and the second opposing surface and connects the first fixed platen and the second fixed platen; and and a movable side connector that is disposed across the third opposing surface and the fourth opposing surface and connects the first movable platen and the second movable platen, The mold clamping device according to claim 1 .

3. The fixed side connector is The first fixed plate and the second fixed plate are detachably fixed to each other, The movable side connector is The movable platen is detachably fixed to the first movable platen and the second movable platen. The mold clamping device according to claim 1 or 2.

4. a fixed-side intermediate body provided between the fixed-side connecting body and the first fixed plate and the second fixed plate; a movable side intermediate body provided between the movable side connector and the first movable platen and the second movable platen, The mold clamping device according to claim 1 or 2.

5. The fixed intermediate body is The fixed side connector is slidable relative to the first fixed plate and the second fixed plate, or the rigidity of the fixed side connector is lower than that of the first fixed platen and the second fixed platen, The movable intermediate body is The movable side connector is slidable relative to the first movable platen and the second movable platen, or the rigidity of which is lower than those of the movable-side connector, the first movable platen, and the second movable platen; The mold clamping device according to claim 4.

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