Mold clamping apparatus

Abstract

To prevent the damage of a fastening means for fixing a mold clamping cylinder to a mold platen in a mold clamping apparatus equipped with the mold clamping cylinder prepared separately from the mold platen.SOLUTION: A mold clamping device (1) of the present invention includes a fixed mold platen (11) which holds a fixed mold, a movable mold platen (13) which holds a movable mold, and a mold clamping cylinder (21) which generates a mold clamping force between a fixed mold (15) and a movable mold (17) via the fixed mold platen (11) and the movable mold platen (13). The mold clamping cylinders (21) are detachably provided at four corners of one of the fixed platen (11) and the movable platen (13) by fasteners. The planar direction components (11F) of the mold clamping force (F) in all or a part of the attachment surfaces (21D, f2) where the mold clamping cylinder (21) and one of the fixed mold platen (11) and the movable mold platen (13) are in contact with each other face the central axis (C) side of the fixed mold platen (11).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a mold clamping device that is applied to a molding machine that uses a pair of molds, such as an injection molding machine or a die-casting machine. [Background technology]

[0002] The clamping unit is equipped with a fixed platen, whose position is fixed during molding, and a movable platen, which moves back and forth relative to the fixed platen. A fixed mold and a movable mold are attached to the fixed platen and the movable mold, respectively, and the material to be molded, molten resin (injection molding machine) or molten metal (die-casting machine), is supplied to the cavity formed between the fixed mold and the movable mold.

[0003] Patent Document 1 proposes a clamping device that can reduce the size and weight of the fixed platen in an extra-large injection molding machine. In this clamping device, a clamping cylinder is prepared as a separate body from the fixed platen, and this separate clamping cylinder is fastened to the fixed platen with bolts so that it can be disassembled.

[0004] When the clamping force of the clamping cylinder is applied between the fixed and movable platens, the fixed and movable platens bend toward each other outside the mold (fixed and movable molds) because a mold is provided between them. This bending causes the clamping cylinder, which is bolted to the fixed platen, to tilt. [Prior art documents] [Patent documents]

[0005] Publication number 7-36733 Summary of the Invention [Problem to be solved by the invention]

[0006] Molds of various sizes are used in mold clamping units, and due to production operation circumstances, molds with dimensions smaller than the minimum design values ​​of the fixed and movable platens are sometimes used, which would otherwise cause problems. This can cause deformation, such as deflection, of the fixed and movable platens to exceed the design assumptions. This deflection causes the outer peripheries of the fixed and movable platens to tilt closer to each other. As a result, the clamping cylinder, which is provided separately from the fixed platen, attempts to shift toward the outside of the fixed platen, which is closer to the platen, thereby mitigating the amount of tie bar elongation, i.e., reducing the strain energy of the tie bars and achieving a stable state. This causes bending and shear forces to be generated in the bolts securing the clamping cylinder to the fixed platen, potentially damaging the bolts. SUMMARY OF THE INVENTION It is therefore an object of the present invention to prevent damage to fastening means for fixing a clamping cylinder to a platen in a clamping device having a clamping cylinder prepared separately from the platen. [Means for solving the problem]

[0007] The mold clamping device of the present invention comprises: a pair of mold plates for holding the pair of molds, respectively; and a clamping cylinder that generates a clamping force on the pair of molds via the pair of mold platens. The mold clamping cylinder in the present invention is The mold plate is detachably attached to the four corners of one of the pair of mold plates by fasteners, The mounting surface is configured so that the planar component of the clamping force at all or part of the mounting surface where the clamping cylinder and one of the pair of platens come into contact faces the central axis of the pair of platens.

[0008] In the present invention, The platen-side mounting surface that constitutes the mounting surface of the platen on which the clamping cylinder is mounted is: Preferably, the platen is tilted so that the thickness increases from the central axis toward the periphery of the platen.

[0009] In the present invention, The cylinder side mounting surface that constitutes the mounting surface of the mold clamping cylinder is It is preferable that the angle be inclined in accordance with the mounting surface on the platen side.

[0010] In the present invention, The inclination of the mounting surface on the platen side is θ11, If the inclination on the cylinder side mounting surface is θ21, then It is preferable that θ11=θ13 be satisfied.

[0011] In the present invention, The mounting surface on the platen side is It is preferable that the mounting surface is set back from the area other than the mounting surface on the platen side.

[0012] In the present invention, It is preferable to provide locking surfaces provided corresponding to the respective clamping cylinders, which restrict positional deviation of the clamping cylinders due to a component in the planar direction.

[0013] In the present invention, The pair of die plates are a fixed platen whose position is fixed; a movable platen that moves forward and backward relative to the fixed platen, The clamping cylinder is preferably attached to the fixed platen. [Effects of the Invention]

[0014] According to the present invention, the clamping cylinder is attached so that the planar component (f2) of the clamping force (F) faces the central axis (C) of the platens (11, 13), which prevents the clamping cylinder from shifting outward from the platens when the clamping force is applied, thereby preventing damage to the fastening means that secures the clamping cylinder to the platens. [Brief explanation of the drawings]

[0015] [Figure 1] 1A and 1B show a mold clamping device according to an embodiment, in which FIG. 1A is a side view and FIG. 1B is a vertical cross-sectional view. [Figure 2]1A and 1B show a mold clamping device according to an embodiment, in which FIG. 1A is a front view and FIG. 1B is a rear view. [Figure 3] 3A and 3B show a fixed platen according to an embodiment, in which FIG. 3A is a front view of the fixed platen, and FIG. 3B is a cross-sectional view taken along line IIIB-IIIB in FIG. 3A. [Figure 4] 1A to 1F show a mold clamping cylinder according to an embodiment, in which (a) is a side view, (b) is a front view, (c) is a rear view, (d) is a plan view, (e) is a bottom view, and (f) is a longitudinal cross-sectional view thereof. [Figure 5] 1A and 1B show the operation of the mold clamping device according to the embodiment, where (a) shows the state before mold clamping and (b) shows the state during mold clamping. [Figure 6] FIG. 6 is a partial enlarged view of the mounting portion of the mold clamping cylinder 21 in FIG. 5. [Figure 7] 7(a) is a partially enlarged view of the mounting portion of the mold clamping cylinder 21 in FIG. 6, and FIG. 7(b) is a view showing a modified example. [Figure 8] 11A shows a modified example in which the locking surface is omitted, and FIG. 11B shows an example in which only the platen-side mounting surface 11F is inclined. [Figure 9] (a) shows a modified example in which the clamping cylinder fits within the range of the mounting surface on the mold platen side, and (b) shows a modified example in which the locking surface 11G consists of only a circular arc, and the clamping cylinder can be attached to the mold platen even if part of it extends outside the range of the mounting surface on the mold platen side. [Figure 10] 1(a) shows the inclination θ30 of the platen side mounting surface 11F relative to a plane perpendicular to the central axis when a conventionally shaped platen, in which the platen side mounting surface and the cylinder side mounting surface are parallel to the mold mounting surface, is deflected during mold clamping, and FIG. 1(b) shows the relationship between the inclination θ11 and θ30 according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, a mold clamping device 1 according to an embodiment will be described with reference to the accompanying drawings. As an example, in a clamping device 1 in which a clamping cylinder 21 is fastened to a fixed platen 11 with a bolt B and made detachable, damage to the bolt B can be prevented by suppressing bending and shear forces (hereinafter collectively referred to as bending stress, etc.) occurring in the bolt B. In the clamping device 1, the mounting surface between the fixed platen 11 and the clamping cylinder 21 is configured so that the planar component f2 (FIG. 7) of the clamping force F at the mounting surface faces the central axis C1 of the fixed platen 11. Below, the configuration of the clamping device 1 will be explained, and then the actions and effects of the clamping device 1 will be mentioned.

[0017] [Configuration of the mold clamping unit 1: see Figures 1, 2, 3, and 4] 1, the mold clamping device 1 includes a mold section 10 that holds a fixed mold 15 and a movable mold 17, and a mold clamping section 20 that generates a mold clamping force F between the fixed mold 15 and the movable mold 17 that are supported by the mold section 10. In the mold clamping device 1 described below, only the minimum configuration necessary for explaining this embodiment is shown, but it may also include, for example, a configuration for supplying hydraulic oil to a mold clamping cylinder 21, a configuration for moving the movable platen 13 back and forth, and the like. In the mold clamping device 1, the front (F) and rear (R) are defined as shown in FIG.

[0018] [Mold section 10: See Figure 1] The mold section 10 includes a fixed platen 11 on which a fixed mold 15 is held, and a movable platen 13 which holds a movable mold 17. The fixed platen 11 and the movable platen 13 are arranged opposite each other, with the fixed platen 11 provided at a fixed position and the movable platen 13 provided so as to be movable toward and away from the fixed platen 11. The fixed mold 15 and the movable mold 17 are made of steel material known as plastic mold steel. 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 plastic mold steels. Furthermore, cast iron such as spheroidal graphite cast iron or gray cast iron is generally used for the fixed platen 11 and the movable platen 13, but the same steel material as that of the fixed mold 15 and the movable mold 17 may also be used. A tie bar 25, which is an element of the mold clamping section 20, is stretched between the fixed platen 11 and the movable platen 13.

[0019] [Fixed platen 11: see Figures 1, 2(a), and 3] The fixed platen 11 has a mold mounting surface 11A facing the movable platen 13, and a back surface 11B on the back side of the mold mounting surface 11A. A fixed mold 15 is attached to the mold mounting surface 11A, and a clamping cylinder 21 of a mold clamping unit 20 is attached to the back surface 11B. In the fixed platen 11, a nozzle accommodating hole 11C in which an injection nozzle of an injection unit (not shown) is disposed is provided so as to penetrate between the mold mounting surface 11A and the back surface 11B.

[0020] The mold mounting surface 11A is composed of an overall flat surface. On the back surface 11B, mounting areas 11D where the clamping cylinders 21 are attached are set back toward the mold mounting surface 11A compared to other areas on the back surface 13B of the fixed platen 11, meaning that the platen has a thinner wall thickness. In each mounting area 11D, insertion holes 11H for tie bars 25 that penetrate the fixed platen 11 from the mold mounting surface 11A to the back surface 11B are formed.

[0021] In plan view ( FIG. 3( a) ), each mounting zone 11D is roughly fan-shaped, centered on a respective corner 11E of the fixed platen 11, and a circular-arc-shaped locking surface 11G is provided on the side of the central axis C1. The thickness of the fixed platen 11 in the mounting zone 11D increases continuously from the locking surface 11G outward (toward the opposite side from the central axis C1), and the mounting zone 11D slopes from the outer periphery of the fixed platen 11 toward the central axis C1. In this manner, the thickness of the mounting zone 11D increases from the central axis C1 toward the periphery of the fixed platen 11, and as shown in FIG. 3( b ), an inclination θ11 is formed on the platen-side mounting surface 11F included in the mounting zone 11D. In this embodiment, this inclination θ11 is defined as being inclined in the opposite direction to the mold mounting surface 11A relative to the mold mounting surface 11A. θ11 can also be said to be an inclination in the opposite direction to the mold mounting surface 11A with respect to a plane perpendicular to the central axis C1.

[0022] [Movable platen 13: See Figure 1 and Figure 2(b)] The movable platen 13 has a mold mounting surface 13A facing the fixed platen 11, and a back surface 13B on the back side of the mold mounting surface 13A. A movable mold 17 is attached to the mold mounting surface 13A, and a split nut 29 of the mold clamping unit 20 is attached to the back surface 13B. Insertion holes 13F for tie bars 25 that penetrate the mold mounting surface 13A and the back surface 13B are formed in the four corners of the movable platen 13. The movable platen 13 is moved forward and backward relative to the fixed platen 11 by converting the rotational driving force of a servo motor, for example, into linear motion using a ball screw.

[0023] [Mold clamping unit 20: see Figures 1, 2, and 4] The mold clamping unit 20 applies a mold clamping force F to the fixed mold 15 and the movable mold 17 via the fixed mold platen 11 and the movable mold platen 13. The mold clamping unit 20 is provided at each of the four corners of the fixed mold platen 11 and the movable mold platen 13.

[0024] 4, each clamping unit 20 includes a clamping cylinder 21 attached to the fixed platen 11, a ram 23 that slides in the front-to-rear direction inside the clamping cylinder 21, and a tie bar 25 fixed to the ram 23. The tie bar 25 passes through the insertion hole 11H of the fixed platen 11 and the insertion hole 13F of the movable platen 13, with its tip protruding rearward (R) beyond the back surface 13B.

[0025] A hydraulic source (not shown) is connected to the mold clamping cylinder 21, and this hydraulic source supplies hydraulic oil to the mold clamping-side oil chamber 21E or the mold opening-side oil chamber 21F of the mold clamping cylinder 21. When the fixed mold 15 and the movable mold 17 are clamped together, hydraulic oil is supplied to the mold clamping-side oil chamber 21E, and when the fixed mold 15 and the movable mold 17 are opened, hydraulic oil is supplied to the mold opening-side oil chamber 21F. The clamping cylinder 21 is fixed to the fixed platen 11 by a bolt B, as shown in FIG.

[0026] The tip of each tie bar 25, which protrudes rearward (R) from the back surface 13B, is formed with, for example, a plurality of ring ridges (or male threads) with an equal pitch. This tip is provided with a split nut 29 having a ring-shaped inner groove (female thread) that meshes with the ring ridges. During mold clamping, the split nut 29 meshes with the tie bar 25, and the tie bar 25 moves toward the fixed platen 11, thereby abutting against the back surface 13B of the movable platen 13 and moving the movable platen 13 toward the fixed platen 11.

[0027] In the mold clamping section 20, the mold clamping cylinder 21 has a distinctive external shape. This external shape follows the shape of the mounting area 11D of the mold clamping device 1. The mold clamping cylinder 21 includes a cylindrical body 21A, a closing body 21B that closes the front (F) end of the body 21A, and a closing body 21C that closes the rear (R) side of the body 21A. The tie bars 25 extend to the outside of the mold clamping cylinder 21 through the closing body 21C.

[0028] While the obturator 21B is formed perpendicular to the central axis C2 of the tie bar 25, the obturator 21C is formed at an inclination with respect to the central axis C2. The inclination of this obturator 21C follows the inclination θ11 of the platen-side mounting surface 11F, and is set so that when the mold clamping cylinder 21 is attached to the platen so that the central axis C2 of the tie bar 25 is parallel to the central axis C1 of the platen, the obturator 21C will be in close contact with or abut against the mounting surface 11F of the mold clamping unit 1. That is, as shown in FIG. 4(a), if the inclination of the obturator 21C with respect to the mold mounting surface 11A is θ21, then the obturator 21C is most preferably formed so that θ11 = θ21. The surface of the obturator 21C inclined by θ21 is referred to as the cylinder-side mounting surface 21D. The present invention allows θ11 ≠ θ21.

[0029] [Attachment state of the clamping cylinder 21 to the fixed platen 11: see Figures 1, 2, 3, and 4] The clamping cylinder 21 is attached and fixed to the fixed platen 11 with the cylinder-side mounting surface 21D abutting against the platen-side mounting surface 11F. As an example, a portion of the clamping cylinder 21 protrudes outward beyond the periphery of the fixed platen 11, but this is to make it easier to understand the state of the fixed part where the clamping cylinder 21 is separate from the fixed platen 11, and the present invention is not limited to this.

[0030] Each clamping cylinder 21 is held in the mounting area 11D with its cylinder-side mounting surface 21D abutting against the platen-side mounting surface 11F and its body 21A abutting against the locking surface 11G. As shown in Fig. 6, the body 21A of the clamping cylinder 21 is fixed to the fixed platen 11 with a bolt B.

[0031] [Deformation of the platen due to mold clamping: see Figure 5] The states of the fixed mold 15 and the movable mold 17 before and after the clamping force is applied are shown in FIGS. 5(a) and 5(b). 5(a) and 5(b), when a clamping force is applied, the fixed platen 11 and the movable platen 13 bend so as to approach each other outside the fixed mold 15 and the movable mold 17, with the fixed mold 15 and the movable mold 17 present between them becoming the fixed ends. However, in the clamping device 1, as will be explained below, even if the fixed platen 11 and the movable platen 13 bend, damage to the bolts B that secure the clamping cylinder 21 to the fixed platen 11 can be suppressed. 5(b), the deflection of the fixed platen 11 and the movable platen 13 is exaggerated. Also, in FIG. 5(b), the clamping cylinder 21 is depicted as not being subjected to a clamping force and not being deflected.

[0032] [Clamping force: See Figures 6 and 7] When clamping the fixed mold 15 and the movable mold 17, hydraulic oil is supplied to the clamping-side oil chamber 21E of the clamping cylinder 21. Then, as shown in FIG. 6, a clamping force F is generated in each clamping cylinder 21, as shown in the following formula (1).

[0033] F=p×s … (1) F: mold clamping force, p: hydraulic pressure of hydraulic oil, s: cross-sectional area of ​​mold clamping side oil chamber 21E

[0034] At the cylinder-side mounting surface 21D and the platen-side mounting surface 11F (hereinafter simply referred to as the mounting surface), the clamping force F can be divided into a component f1 normal to the mounting surface and a component f2 in the plane direction of the mounting surface. Here, the cylinder-side mounting surface 21D and the platen-side mounting surface 11F, which constitute the mounting surfaces, are inclined as described above. Therefore, the plane direction component f2 of the clamping force F is generated so that the clamping cylinder 21 moves toward the central axis C1 of the fixed platen 11. However, because the clamping cylinder 21 abuts against the locking surface 11G, displacement toward the central axis C1 is restrained and the original position is maintained. As a result, the bolt B remains straight, or even if bending stress or the like occurs in the bolt B, it is minimized, thereby preventing damage to the bolt B. If an unexpectedly large deflection occurs in the fixed platen 11, the planar component f2 faces outward, away from the central axis C1, which could cause the clamping cylinder 21 to shift outward from the fixed platen 11. However, even in this case, the platen mounting surface 11F is tilted in the opposite direction from the mold mounting surface 11A relative to the mold mounting surface 11A, or in the opposite direction from the mold mounting surface 11A relative to a plane perpendicular to the central axis C1. Therefore, the platen mounting surface 11F protrudes in the opposite direction from the mold mounting surface 11A the farther outward from the central axis C1 of the platen. Therefore, in order for the clamping cylinder 21 to shift outward, the clamping cylinder 21 must move in the opposite direction from the mold mounting surface 11A. However, moving the clamping cylinder 21 in the opposite direction from the mold mounting surface 11A would increase the elongation of the tie bars 25, which would require a larger clamping force. However, since the clamping force does not increase, the clamping cylinder 21 will not shift outward. This prevents damage to the bolts B.

[0035] In contrast to the above, when the platen-side mounting surface 11F and the cylinder-side mounting surface 21D are parallel to the mold mounting surface 11A and perpendicular to the central axis C1, as can be easily understood, if the fixed platen 11 tilts toward the movable platen 13, a planar direction component f2 occurs in the clamping cylinder 21 in a direction away from the central axis C1 of the fixed platen 11, causing the clamping cylinder 21 to shift outward. This is because the clamping cylinder 21 can mitigate the amount of elongation of the tie-bars 25, that is, the strain energy of the tie-bars 25 becomes smaller and a stable state is achieved, and the clamping cylinder 21 tends to shift outward from the fixed platen 11, which is closer to the platen. This causes bending stress and the like to occur in the bolts B that secure the clamping cylinder 21 to the fixed platen 11.

[0036] The inclinations θ11 and θ21 are determined taking into consideration the deflection of the fixed platen 11 during clamping. In other words, the inclinations θ11 and θ21 are set so that even if the fixed platen 11 deflects, the planar direction component f2 faces the central axis C1 and the clamping cylinder 21 does not shift outward. Therefore, when the platen-side mounting surface 11F and the cylinder-side mounting surface 21D are parallel to the mold mounting surface 11A and perpendicular to the central axis C1, the inclination of the platen-side mounting surface 11F when the platen deflects during clamping is set to θ30 (see FIG. 10(a)). If the fixed platen 11 is manufactured so that the tilt θ11>tilt θ30 is satisfied, even if the platen bends during mold clamping, the platen-side mounting surface 11F will remain tilted in the opposite direction from the mold mounting surface 11A relative to the mold mounting surface 11A, or in the opposite direction from the mold mounting surface 11A relative to a plane perpendicular to the central axis C1 (see FIG. 10(b)), so that the planar direction component f2 faces toward the central axis C1. Furthermore, whether the planar direction component f2 faces toward the central axis C1 can be determined dynamically, even without actually clamping, by specifying the shape, dimensions, mechanical and tilt θ11 (θ21) specifications of the fixed platen 11.

[0037] [Effects of mold clamping unit 1] <First effect> According to the mold clamping device 1, the planar component f2 of the mold clamping force F acts on the mold clamping cylinder 21 so that it faces the central axis C1 of the fixed platen 11, thereby restricting outward positional deviation of the mold clamping cylinder 21. As a result, bending stress or the like is not generated in the bolt B that attaches the mold clamping cylinder 21 to the fixed platen 11, or even if it is generated, it can be kept to a minimum, thereby preventing damage to the bolt B.

[0038] <Second effect> According to the mold clamping device 1, even if the mold clamping cylinder 21 attempts to shift toward the central axis C1, the mold clamping cylinder 21 is locked by the locking surface 11G. Therefore, damage to the bolt B due to the mold clamping cylinder 21 shifting toward the central axis C1 can be suppressed.

[0039] <Third Effect> According to the mold clamping device 1, the inclination θ11 of the platen-side mounting surface 11F relative to the mold mounting surface 11A and the inclination θ21 of the cylinder-side mounting surface 21D relative to the mold mounting surface 11A are set to θ11 = θ21. As a result, when the mold clamping cylinder 21 is locked on the locking surface 11G, the platen-side mounting surface 11F and the cylinder-side mounting surface 21D can be fixed in close contact with each other, maximizing the friction between the platen-side mounting surface 11F and the cylinder-side mounting surface 21D, thereby effectively preventing or suppressing the occurrence of positional deviation of the mold clamping cylinder 21 relative to the fixed platen 11.

[0040] <Fourth Effect> According to the mold clamping device 1, the mounting area 11D where the mold clamping cylinder 21 is attached is set back toward the mold mounting surface 11A relative to other portions on the back surface 11B of the fixed platen 11. By doing so, even if the planar component f2 of the mold clamping force F is generated in the direction of the mold clamping cylinder 21 toward the central axis C1 of the fixed platen 11 and presses the mold clamping cylinder 21 against the locking surface 11G, there is another portion on the back surface 11B of the fixed platen 11 that is highly rigid behind the locking surface 11G, which has the effect of making it easier to hold the locking surface 11G.

[0041] In addition to the above, the configurations given in the above embodiments can be selected or changed as appropriate to other configurations without departing from the spirit of the present invention. Although the above describes an example in which the clamping cylinder 21 is attached to the fixed platen 11, it is also possible to provide the clamping cylinder 21 on the side of the movable platen 13 and provide an attachment surface similar to the platen-side attachment surface 11F on the back surface 13B of the movable platen 13. However, when the clamping cylinder 21 is attached to the movable platen 13, the movable platen 13 becomes a heavy object that includes the clamping cylinder 21 in addition to the movable platen 13. In order to move the movable platen 13, which is a heavy object, back and forth, it is necessary to increase the output of the drive source.

[0042] Although the entire platen-side mounting surface 11F and the cylinder-side mounting surface 21D are inclined as described above, the present invention is not limited to this. For example, as shown in FIG. 7(b), the planar direction component f2 of the clamping cylinder 21 can be oriented in a desired direction by providing an inclination only to a portion of the platen-side mounting surface 11F and the cylinder-side mounting surface 21D. Note that there are other examples in which an inclination is provided only to a portion of the platen-side mounting surface 11F and the cylinder-side mounting surface 21D, which will be described later.

[0043] In the above-described configuration, the platen-side mounting surface 11F of the fixed platen 11 is recessed toward the mold mounting surface 11A, but the present invention is not limited to this. For example, as shown in Fig. 8(a), the platen-side mounting surface 11F can be formed to protrude further than other portions. In this configuration, although no locking surface 11G is provided, when the deflection of the fixed platen 11 is small and the planar direction component f2 is small, the locking end 21G of the clamping cylinder 21 abuts against the back surface 11B, generating a frictional force, thereby restricting displacement of the clamping cylinder 21.

[0044] In the mold clamping unit 1 described above, the fixed platen 11 is provided with the platen-side mounting surface 11F and the clamping cylinder 21 is provided with the cylinder-side mounting surface 21D, but the present invention is not limited to this. As shown in Fig. 8(b), the planar direction component f2 can also be made to face the central axis C1 side by providing the platen-side mounting surface 11F that is inclined only toward the fixed platen 11 side.

[0045] In the mold clamping unit 1 described above, the fixed platen 11 is provided with a platen-side mounting surface 11F that is inclined relative to the mold mounting surface 11A, but the present invention is not limited to this. The rear surface 13B of the movable platen 13, on which the split nut 29 abuts, may also be provided with a surface that is inclined relative to the mold mounting surface 13A.

[0046] In the mold clamping unit 1 described above, a portion of the mold clamping cylinder 21 protrudes outward beyond the periphery of the fixed platen 11, but the present invention is not limited to this. For example, as shown in Fig. 9(a), the mold clamping cylinder 21 may be arranged to fit within the range of the platen-side mounting surface 11F.

[0047] Although the platen-side mounting surface 11F of the fixed platen 11 of the clamping unit 1 described above is inclined in plan view, the present invention is not limited to this. For example, as shown in FIG. 9(b), only a portion of the platen-side mounting surface 11F, including the tie bar 25 insertion holes 11H, can be inclined and protrude from the surrounding area, as shown by the hatched area, while the remaining white area can be flat. In this case, it is preferable that the protruding portion of the portion including the tie bar 25 insertion holes 11H be radially arranged relative to the central axis C1. This is because the mold is mounted at the center of the platen, and therefore the platen deflects in a manner that envelops the mold. Therefore, the deflection of the platen at the four corners where the clamping cylinders 21 are mounted increases radially relative to the central axis C1. [Explanation of symbols]

[0048] 1 Mold clamping device 10. Mold Department 11 Fixed platen 11A Mold mounting surface 11B Back 11C Nozzle housing hole 11D Mounting area 11E Corner 11F Platen side mounting surface 11G Locking surface 11H insertion hole 13 Movable mold board 13A Mold mounting surface 13B Back 13F insertion hole 15 Fixed mold 17 Movable mold 20 Mold clamping part 21 Mold clamping cylinder 21A fuselage 21B Obturator 21C Obstruction body 21D Cylinder side mounting surface 21E Clamping side oil chamber 21F Mold opening side oil chamber 21G Locking end 23 Ram 25 tie bar 29 Split Nut B Bolt C1,C2 center axis F Clamping force f1 Normal direction component f2 Planar direction component

Claims

1. a pair of mold plates for holding the pair of molds, respectively; a clamping cylinder that generates a clamping force on the pair of molds via the pair of mold platens, The mold clamping cylinder is a pair of mold plates attached to four corners of one of the pair of mold plates by fasteners in a detachable manner; A mold clamping device in which the mounting surface is configured so that the planar component of the mold clamping force in all or part of the mounting surface where the mold clamping cylinder and one of the pair of mold plates contact faces toward the central axis of the pair of mold plates.

2. The platen-side mounting surface constituting the mounting surface of the platen to which the clamping cylinder is attached is The platen is inclined so that the thickness of the platen increases from the central axis toward the periphery of the platen. The mold clamping device according to claim 1 .

3. The cylinder side mounting surface constituting the mounting surface of the mold clamping cylinder is The platen side mounting surface is inclined in accordance with the platen side mounting surface. The mold clamping device according to claim 2 .

4. The inclination on the platen side mounting surface is defined as θ11, If the inclination on the cylinder side mounting surface is θ21, θ11=θ21 is satisfied. The mold clamping device according to claim 3 .

5. The platen side mounting surface is The platen side mounting surface is recessed from the other portion. The mold clamping device according to claim 2 .

6. a locking surface provided corresponding to each of the mold clamping cylinders, which restricts positional deviation of the mold clamping cylinders due to the planar direction component; The mold clamping device according to claim 1 .

7. The pair of die plates are a fixed platen whose position is fixed; a movable platen that moves forward and backward relative to the fixed platen, The clamping cylinder is attached to the fixed platen. The mold clamping device according to claim 1 .

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