mold clamping device

Abstract

Provided is a mold clamping device that can prevent damage to a movable platen from a link. The mold clamping device includes a movable platen that moves along a link, and a plurality of lift mechanisms including a first lift mechanism and a second lift mechanism. The mold clamping device includes a drive mechanism configured to impart a differential so that a first portion of the movable platen corresponding to the first lift mechanism is at a position higher than or lower than a second portion of the movable platen corresponding to the second lift mechanism, thereby moving the movable platen, and a link structure that links the drive mechanism to the movable platen. The link structure is configured as a stopper that restricts movement of the movable platen so that the differential is not greater than a prescribed value.

Description

Technical Field

[0001] This invention relates to a mold closing device comprising multiple lifting mechanisms. Background Technology

[0002] The goal is to minimize the total thickness variation (TTV), which is the difference between the maximum and minimum thickness of the resin sealant. To reduce TTV, the gap between the fixed and movable pressure plates must be precisely adjusted during mold closing, and the upper and lower molds must be arranged parallel to each other. For example, Patent Documents 1 and 2 disclose a mold closing device that includes multiple lifting mechanisms, and the height of the movable pressure plate can be arbitrarily adjusted for each part corresponding to each lifting mechanism.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-324377

[0006] Patent Document 2: Japanese Patent Application Publication No. 2008-087408 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] However, because the gap between the movable pressure plate and the connecting rod that guides its lifting is very small, there is a concern that if the height difference between the lifting mechanisms becomes too large, the movable pressure plate may tilt excessively and damage the connecting rod. Therefore, the object of the present invention is to provide a mold closing device that can prevent the movable pressure plate from damaging the connecting rod.

[0009] Technical means to solve the problem

[0010] An embodiment of the mold-closing device of the present invention includes: a movable pressure plate that moves along a connecting rod; and a plurality of lifting structures, including a first lifting mechanism and a second lifting mechanism. The mold-closing device further includes: a drive mechanism configured to impart a differential position such that a first portion of the movable pressure plate corresponding to the first lifting mechanism is positioned higher or lower than a second portion of the movable pressure plate corresponding to the second lifting mechanism, thereby moving the movable pressure plate; and a connecting structure connecting the drive mechanism to the movable pressure plate. The connecting structure is configured as a stop member that restricts the movement of the movable pressure plate so that the differential does not exceed a predetermined value.

[0011] According to the embodiment described, even if the differential is increased beyond a predetermined value, the connecting structure restricts the movement of the movable pressure plate. Therefore, the possibility of the movable pressure plate tilting excessively and damaging the connecting rod can be prevented.

[0012] In the embodiment, the connecting structure may include multiple connecting members installed on the first lifting mechanism.

[0013] According to the embodiment described, stress can be distributed to multiple connecting structures in each lifting mechanism. For example, this is preferred when the lifting mechanism is a ball screw or similar device that generates a large rotational load around the shaft.

[0014] In the embodiment described, each of the multiple connecting members can form a free rod structure with a movable area of ​​a specified value.

[0015] According to the embodiment described, the movement of the movable pressure plate can be limited by a simple, readily available structure so that the difference does not exceed a predetermined value.

[0016] In the embodiment described above, the movable pressure plate can also be configured to slide smoothly on the surface of the connecting rod when the difference is equal to the specified value.

[0017] According to the embodiment, as long as the difference is below a specified value, all lifting mechanisms can be driven at a constant speed to perform operations such as mold closing or mold opening while the correction value of the difference is added and the movable pressure plate is tilted.

[0018] In the embodiment described, the drive mechanism may also include four lifting mechanisms.

[0019] According to the embodiment described, the lifting mechanisms can be configured such that each of the four links comprising the four lifting mechanisms is equidistant from the nearest lifting mechanism. This allows force to be evenly transmitted to each part, enabling the movable pressure plate to move.

[0020] The effects of the invention

[0021] According to the present invention, a mold closing device can be provided that can prevent damage to the connecting rod of the movable pressure plate. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view showing a mold clamping device according to an embodiment of the present invention.

[0023] Figure 2 It is a general representation Figure 1 The diagram shows a plan view of the movable pressure plate.

[0024] Figure 3 It is Figure 1 The connection structure shown is represented by an enlarged cross-sectional view.

[0025] [Explanation of Symbols]

[0026] 1: Mold closing device

[0027] 2: Fixed pressure plate

[0028] 3: Movable pressure plate

[0029] 3A, 3B, 3C, 3D: Parts 1 to 4

[0030] 4: Linkage

[0031] 10: Drive mechanism

[0032] 10A, 10B, 10C, 10D: First to fourth lifting mechanisms

[0033] 11: Shaft (Ball Screw)

[0034] 12: Nuts

[0035] 13: Ring

[0036] 14: Fastening screws

[0037] 15: Motor

[0038] 20: Connection Structure

[0039] 20A, 20B: Connecting parts

[0040] 21: Head

[0041] 22: Cylindrical section

[0042] 23: Threaded section

[0043] 131: Main Body

[0044] 132: Flange section

[0045] 133: Through hole

[0046] α: Specified value

[0047] β: Difference Detailed Implementation

[0048] Preferred embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in the figures, elements labeled with the same reference numerals have the same or identical structures. One embodiment of the present invention is a mold-closing device 1 that closes upper and lower molds in compression molding or transfer molding. If an upper mold and a lower mold are installed between a fixed pressure plate 2 and a movable pressure plate 3, a resin sealing device for sealing semiconductor chips, etc., can be constructed. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

[0049] Figure 1 This is a cross-sectional view showing a mold clamping device 1 according to an embodiment of the present invention, and it is a cross-sectional view cut by a plane passing through the center of the shaft portion 11 of the first lifting mechanism 10A and the second lifting mechanism 10B, which will be described later. Figure 1As shown, the mold clamping device 1 includes: a cylindrical connecting rod 4 extending vertically, a fixed pressure plate (also called "fixed plate") 2 fixed to the end of the connecting rod 4, a movable pressure plate (also called "movable plate") 3 that moves vertically along the connecting rod 4, a drive mechanism 10 that moves the movable pressure plate 3 vertically, and a connecting structure 20 that connects the drive mechanism 10 to the movable pressure plate 3, etc.

[0050] The drive mechanism 10 includes multiple lifting mechanisms (10A, 10B, ...), including a first lifting mechanism 10A and a second lifting mechanism 10B. In the illustrated example, the fixed pressure plate 2 is positioned on the upper side and the movable pressure plate 3 is positioned on the lower side, but the fixed pressure plate 2 can also be positioned on the lower side and the movable pressure plate 3 on the upper side. Each lifting mechanism 10A, 10B, ... includes, for example, ball screws (11, 12, 13, 14), a motor 15, a transmission mechanism not shown, etc.

[0051] Although not shown in the diagram, the transmission mechanism includes, for example, a speed reducer, belt, pulley, etc. The ball screw includes a shaft 11, a nut 12, a ring 13, and fastening screws 14. The shaft 11 extends parallel to the extension direction of the connecting rod 4 and is driven to rotate by a servo-controlled motor 15 via the transmission mechanism. When the shaft 11 rotates, the nut 12 moves linearly in the up-down direction. The ring 13 is fixed to the nut 12 by multiple fastening screws 14.

[0052] The mold clamping device 1 can be given a differential β so that the first part 3A corresponding to the first lifting mechanism 10A ( Figure 2 As shown, it is located in the second part 3B corresponding to the second lifting mechanism 10B. Figure 2 The movable pressure plate 3 is moved by positioning it at a higher position (as shown) or at a lower position than the second part 3B corresponding to the second lifting mechanism 10B. These multiple lifting mechanisms (10A, 10B, ...) that cooperate to move the movable pressure plate 3 up and down are collectively referred to as the drive mechanism 10.

[0053] Figure 2 It is a general representation Figure 1 The diagram shows a plan view of the movable pressure plate 3. In the illustrated example, the drive mechanism 10 of the mold clamping device 1 includes four lifting mechanisms 10A, 10B, 10C, and 10D. The drive mechanism 10 can be composed of three or fewer lifting mechanisms, or it can be composed of five or more lifting mechanisms. Each lifting mechanism 10A, 10B, 10C, and 10D presses against the corresponding parts 3A, 3B, 3C, and 3D located directly above the lifting mechanism.

[0054] Furthermore, in the illustrated example, when viewed from the front, the first lifting mechanism 10A and the second lifting mechanism 10B of the first to fourth lifting mechanisms 10A, 10B, 10C, and 10D are arranged horizontally. However, the first lifting mechanism 10A and the second lifting mechanism 10B can also be arranged front-to-back, or they can be arranged at an angle (on the diagonal of the roughly rectangular movable pressure plate 3). That is, the height difference β between the first part 3A and the second part 3B of the movable pressure plate 3 is not limited to the horizontal height difference within the movable pressure plate 3; it can be the horizontal height difference or the diagonal height difference.

[0055] Figure 3 It is Figure 1 The diagram shows an enlarged cross-sectional view of the connecting structure 20. Multiple (e.g., eight) connecting elements (20A, 20B, ...) are installed in the first lifting mechanism 10A. Similarly, multiple (e.g., eight) connecting elements (20A, 20B, ...) are also installed in the other lifting mechanisms 10B, 10C, 10D. These multiple connecting elements (20A, 20B, ...) are collectively referred to as connecting structure 20.

[0056] like Figure 3 As shown, the ring 13 of the first lifting mechanism 10A is provided with a cylindrical body 131, a flange portion 132 that radiates from the upper end of the body 131, and a through hole 133 that passes through the flange portion 132 along the extension direction (vertical direction) of the connecting rod 4. Each connecting part 20A, 20B, ... is, for example, a fastening screw, having a threaded portion 23 with an external thread that engages with the movable pressure plate 3, a cylindrical portion 22 with a diameter approximately the same as the through hole 133 of the ring 13, and a head 21 with a diameter larger than the through hole 133.

[0057] The surface of the cylindrical portion 22 is a smooth cylinder without any bumps or depressions, and it slides in contact with the inner circumferential surface of the through hole 133 of approximately the same diameter. A gap of length α exists between the bearing surfaces of the heads 21 of the connectors 20A and 20B and the lower surface of the flange portion 132 of the ring 13. In other words, the connectors 20A, 20B, ... and the flange portion 132 constitute a free rod structure with a movable area having a predetermined value α.

[0058] Therefore, even if the first lifting mechanism 10A raises or lowers the position of the movable pressure plate 3 within the specified value α, the flange 132 and the head 21 of the connecting member 20A will not come into contact. On the other hand, even if the first lifting mechanism 10A is moved beyond the specified value α, the head 21 of the connecting member 20A will come into contact with the flange 132, thus restricting further movement of the movable pressure plate 3.

[0059] According to the mold clamping device 1 of this embodiment configured as described above, even if the difference β exceeds the predetermined value α, the connecting structure 20 restricts the movement of the movable pressure plate 3. Therefore, the possibility of the movable pressure plate 3 tilting excessively and damaging the connecting rod 4 can be prevented. Even if the difference β is at its maximum within the range of the predetermined value α, since the movable pressure plate 3 can slide smoothly on the surface of the connecting rod 4, the mold clamping device 1 can be used without damaging the connecting rod 4.

[0060] The nut 12 of the ball screw not only moves linearly in the extending direction of the shaft 11, but also applies a rotational load about the shaft 11 due to friction with the shaft 11. In this embodiment, a plurality of connecting members 20A, 20B, ... are provided around the shaft of the first lifting mechanism 10A, so that this rotational load can be distributed.

[0061] The embodiments described above are for the purpose of understanding the present invention and are not intended to limit or explain the present invention. The various elements, their configurations, materials, conditions, shapes, and dimensions included in the embodiments are not limited to the examples shown and can be appropriately modified. Furthermore, it is possible to perform region substitutions or combinations between the structures shown in different embodiments.

[0062] For example, the stop that restricts the movement of the movable pressure plate 3 is not limited to... Figure 3 The example shown can also be a hook that engages when the height difference β between the first part 3A and the second part 3B of the movable pressure plate 3 reaches a predetermined value α.

Claims

1. A mold clamping device, comprising: The movable pressure plate moves along the connecting rod; as well as The drive mechanism has multiple lifting mechanisms, including a first lifting mechanism and a second lifting mechanism. The drive mechanism is configured to provide a differential, such that a first part of the movable pressure plate corresponding to the first lifting mechanism is at a position higher than or lower than a second part of the movable pressure plate corresponding to the second lifting mechanism, thereby moving the movable pressure plate. as well as A connecting structure connects the drive mechanism to the movable pressure plate. The connecting structure forms a stop, which restricts the movement of the movable pressure plate so that the difference does not exceed a predetermined value. The connection structure includes multiple connecting components installed on the first lifting mechanism. Each of the plurality of connecting members constitutes a free rod structure with a movable region having the specified value.

2. The mold clamping device according to claim 1, wherein, The movable pressure plate is configured such that, when the difference is equal to the specified value, it can slide smoothly on the surface of the connecting rod.

3. The mold clamping device according to claim 1 or 2, wherein, The drive mechanism includes four lifting mechanisms.

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