JP4200624B2 - Pressure mechanism of mold clamping device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a mold clamping apparatus such as an injection molding machine or a die-cast molding machine, and is a so-called hybrid mold clamping system that combines a hydraulic drive system conventionally used for a large mold clamping apparatus and an electric drive system used for a small mold clamping apparatus. The present invention provides a pressurizing mechanism of a mold clamping device that greatly improves energy saving in the device.
[0002]
[Prior art]
In direct pressure mold clamping devices used in injection molding machines, die casting machines, etc., it is necessary to open and close the mold at a high speed in order to shorten the molding cycle. On the other hand, a strong mold clamping force is used to resist the molding pressure. I need. In order to satisfy such conditions, the mechanism of this kind of direct pressure type mold clamping device is generally complicated, and there are various types.
[0003]
FIG. 9 shows a booster ram type mold closing switch. The mold clamping opening / closing device includes a fixed platen 5a and a movable platen 5b. The mold clamping ram 2 is slid into the mold clamping cylinder 1 at the back of the movable platen 5b, and the fast feed ram 3 is inserted into the cylinder of the mold clamping ram 2. The pressure oil for closing the mold is supplied from an oil passage 3a provided in the container. That is, high-speed mold closing is performed by supplying pressure oil from the fast feed ram 3 into the cylinder 2a of the mold clamping ram 2, and strong mold clamping is performed by supplying pressure oil to the rear oil chamber 1a of the mold clamping cylinder 1. The opening is performed by supplying pressure oil to the front oil chamber 1 b of the mold clamping cylinder 1. Reference numeral 4 denotes a prefill valve.
[0004]
[Problems to be solved by the invention]
However, the conventional mold opening / closing device has various problems. That is, in the booster ram type shown in FIG. 9, since the mold opening is performed in the front oil chamber of the mold clamping cylinder 1, the accuracy of the entire cylinder inner surface of the mold clamping cylinder 1 is required and the diameter is increased. Since it is large, precision processing is not easy and processing costs are high. In addition, in the case of using a large-diameter clamping cylinder for such mold opening, the total length of the die casting machine or the injection molding machine becomes long, and it is difficult to install in a small space. There's a problem.
[0005]
In order to solve such a problem, in Japanese Patent Laid-Open No. 10-94864, as shown in FIGS. 10 and 11, a die mounting plate is fixed to a fixed platen 8 provided with tie rods 6 at a plurality of corners. 10 is overlapped and supported, and a cylinder hole 12 opened to the mold mounting plate 10 side is provided in the fixed platen 8. Further, a ram 14 slidably fitted to the cylinder hole 12 is provided, and a sealed bag 16 (see FIG. 11) in which hydraulic pressure is sealed is incorporated, and the ram 14 is increased by increasing the hydraulic pressure in the sealed bag 16. A pressing force for pressing the mold mounting plate 10 toward the fixed mold 18 is applied.
[0006]
However, when the above-described airtight bag 16 is used, when pressure oil is supplied into the airtight bag 16 and the airtight bag 16 is inflated to press the ram 14 or the pressure oil is discharged from the airtight bag 16, When the hermetic bag 16 is shrunk by retreating, as shown in FIGS. 12A and 12B, as a result of repeated use of the hermetic bag 16 by expansion and contraction, a part of the hermetic bag 16 is fixed to the fixed platen 8 and the ram 14. There is a problem that it is pushed into the clearance H1 between the two, and finally the sealed bag 16 is broken during long-term use.
[0007]
The present invention has been made paying attention to the above-mentioned conventional problems, and the object of the present invention is to make the entire length of a die casting machine, an injection molding machine or the like as short as possible, and to clamp the mold without taking up an installation place. An object of the present invention is to provide a pressurizing mechanism for a mold clamping device that can perform the above process quickly and has excellent durability.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, according to a first aspect of the present invention, a pressurizing mechanism of a mold clamping device includes a movable platen having a movable mold and disposed so as to be able to move forward and backward, and opposed to the movable platen. A fixed platen having a fixed mold disposed, a mold mounting plate for mounting the fixed mold between the fixed platen and the fixed mold, a cylinder fitted in a recess provided in the fixed platen, A slide member that is loosely fitted in the cylinder and can project toward the mold mounting plate; and is disposed between the slide member and the bottom plate of the cylinder and is expanded and contracted according to pressure supply / discharge. An expandable bag that can be clamped between the movable and fixed molds via the slide member, and a space recessed in the outer periphery in the vicinity of the end of the slide member are loaded into the expandable bag when the expandable bag is inflated. Pressed by the expansion force of And a movable mold and a fixed mold through a mold mounting plate due to the protrusion of the slide member accompanying the expansion of the expansion and contraction bag as a configuration comprising a flexible protective member capable of closing the gap between the slide member and the cylinder. A pressing force for clamping the mold is applied between the mold and the gap between the expansion and contraction bags is blocked by the sealing action of the flexible protection member to protect the expansion and contraction bags.
Furthermore, in the second invention according to the first invention, the sealing member is formed as a soft piston ring made of a fiber material having a hard reinforcing portion at a corner of a rectangular cross section, and durability of the protective member And simplification of replacement as required.
In the third invention according to the first invention, the sealing member is arranged in a superimposed manner consisting of a hard backup ring and a soft piston ring arranged adjacent to the expansion and contraction bag, so that the sliding member is smooth. I tried to slide.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments of a pressurizing mechanism of a mold clamping device according to the present invention will be described in detail with reference to the drawings.
[0010]
As shown in FIG. 5, a fixed platen 52 is erected on one end portion of a machine base 59 with a base portion being keyed, and a movable platen 54 that can move forward and backward with respect to the fixed platen 52 is provided with a fixed platen 52. It stands upright. A ball nut 73 is provided at a stepped portion of a through hole 54a drilled at a corner of a vertical plane of the movable platen 54, and a shaft end of a ball screw member 72 having a screw portion 72a screwed with the ball nut 73 is The ball screw member 72 is fed concentrically to the output shaft of a servo motor 71 for mold opening / closing drive mounted on the upper surface of the fixed platen 52, and controls the drive of the servo motor 71 in both forward and reverse directions. Through this action, the movable platen 54 is integrated with the guide shoe 66 to move forward and backward with respect to the fixed platen 52, so that the movable mold 84 attached to the movable platen 54 is opened and closed with respect to the fixed mold 82. It is like that.
[0011]
One end of a tie rod 61 that passes through a pressure plate 56 (described later) provided as a mold mounting plate to which the fixed platen 52, the movable platen 54, and the fixed platen 52 are mounted is connected to the end plate 58 at a predetermined interval and is prevented from rotating. The other end of the threaded portion 61 a is screwed to the tie rod nut 62.
The tie rod nut 62 is provided with a tie rod nut rotating member 63 that is rotated by a servo motor 69 via a belt. Further, a tie rod nut presser fitting 64 that covers a step portion of the tie rod nut 62 is a fixed platen 52. The tie rod nut 62 surrounded by the tie rod nut presser fitting 64 and the fixed platen 52 is secured to be rotated.
[0012]
A plurality of ring grooves 61b are formed on the outer peripheral surface of the intermediate portion of the tie rod 61. On the other hand, a half provided on the side opposite to the mold mounting surface of the movable platen 54, that is, on the side opposite to the mold mounting surface. On the inner peripheral surface of the nut 55, inner peripheral protrusions that can be meshed with appropriate positions of the ring groove 61b are formed.
As described above, while the movable platen 54 and the movable mold 84 are being opened and closed, the half nut 55 is held in a half state. However, after the fixed mold 82 and the movable mold 84 are closed, the nut cylinder 68 is moved. By actuating and closing the half nut 55, the inner peripheral projections of the half nut 55 are respectively engaged with the ring grooves 61b to hold the movable platen 54 and the tie rod 61 in an engaged state.
[0013]
In order to hold the movable platen 54 and the tie rod 61 in the engaged state as described above, the position of each ring groove 61b is the half nut 55 in a state where the fixed mold 82 and the movable mold 84 are closed. It must coincide with the proper position for meshing with the inner peripheral projection. Therefore, when the mold is replaced, the tie rod 61 is moved in the axial direction in accordance with the mold thickness (die height) prior to molding, so that the position of each ring groove 61b becomes the inner peripheral protrusion of the half nut 55. So-called die height adjustment is required to adjust the mesh.
[0014]
In the mold clamping device 50 as shown in FIG. 5, when the four tie rod nut rotating members 63 are rotated in conjunction with each other during die height adjustment, the four tie rods 61 are moved in the axial direction with respect to the fixed platen 52. The length of the threaded portion 61a protruding outside the fixed platen 52 is changed. The thick arrow in FIG. 5 represents the operation content of the tie rod 61 at the time of die height adjustment, and the tie rod 61 itself does not rotate as the tie rod nut 62 rotates, but the axis corresponding to the die height adjustment allowance is shown. It shows moving in the direction. In FIG. 5, reference numeral 60 indicates an extrusion apparatus for extruding a molded product from the mold after the fixed and movable molds 82 and 84 are released.
[0015]
Next, a mechanism for applying a clamping force to the fixed mold 82 and the movable mold 84 which are closed will be described.
A pressure receiving chamber 52a having a bottomed concave shape is formed in the center of the vertical surface of the fixed platen 52 on the side opposite to the tie rod nut 62, and a hollow hydraulic pressure made of a stretchable material is formed on the bottom side of the pressure receiving chamber 52a. A bladder (expandable bag) 51 having a chamber formed therein is accommodated, and a slide member 53 (hereinafter simply referred to as a slide nest) having a front end as a pressing surface is slidable on the opening side of the pressure receiving chamber 52a. The bladder (expandable bag) 51 is confined in a space surrounded by the pressure receiving chamber 52a and the slide insert 53 without any gap.
[0016]
In the slide insert 53, the end surface opposite to the end surface facing the bladder 51 is connected to the pressure plate 56, and the tie rod 61 is inserted into the tie rod holes drilled in the four corners of the pressure plate 56. A fixed mold 82 is attached to the center of the vertical surface of the pressure plate 56 on the side opposite to the slide insert 53 while being penetrated. Further, a compression coil spring 57 is accommodated in the large diameter portion of the plurality of stepped through holes 56 a drilled from the die mounting surface side of the pressure plate 56, and the pressure plate is interposed via the compression coil spring 57. Bolts that connect 56 pass through the small diameter portion of the through hole 56 a and are screwed into the fixed platen 52.
[0017]
Here, as shown in FIG. 6, the inside of the bladder 51 can be filled with hydraulic oil from the oil tank 100 via the pump 88, and the bladder 51 expanded by the internal pressure presses the back surface of the slide insert 53. The force is transmitted to the pressure plate 56 as a mold clamping force.
[0018]
On the other hand, when the hydraulic oil sealed in the bladder 51 is returned to the oil tank 100 side through an appropriate switching valve (not shown) and the pressure is lowered, the stationary mold 82, The positions of the pressure plate 56 and the slide insert 53 are automatically returned to the positions before the action of the mold clamping force.
[0019]
In this way, by controlling the pressure of the hydraulic oil enclosed in the bladder 51 housed in the pressure receiving chamber 52a engraved in the fixed platen 52 of the mold clamping device 50 such as an injection molding machine or a die casting machine. A mold clamping mechanism capable of controlling the mold clamping force acting on the fixed mold 82 and the movable mold 84 sandwiched between the pressure plate 56 and the movable platen 54 is obtained, and the above-described ball screw drive type mold opening / closing drive is obtained. Combined with the mechanism, a clean mold clamping device with excellent energy saving and control accuracy, simple structure, and excellent durability can be obtained.
[0020]
Next, the pressurizing mechanism of the mold clamping apparatus of the present invention will be described with reference to FIG. 1 and FIG. As shown in FIG. 5, a rectangular plate-shaped pressure plate (die mounting plate) 56 having four corner rod holes slidably fitted to tie rods 61 is contacted and separated on the vertical plane of the fixed platen 52. The cylinder holes 52 a are provided on the surface of the fixed platen 52 that faces the pressure plate 56, and are opened toward the pressure plate 56. In the cylinder hole 52a, a bottom plate 42, a cylinder 44, a bladder 51, a slide insert 53, and the like are disposed, and a hydraulic introduction port 46 penetrating the bottom plate 42 is disposed, whereby the pressurizing mechanism 40 of the mold clamping device is provided. It is configured.
[0021]
As shown in FIG. 1, the pressurizing mechanism 40 of the mold clamping device is slidably fitted into a cylindrical cylinder 44 fitted into the cylinder hole 52a and bolted thereto, and an inner hole of the cylinder 44. The slide insert 53 is provided so that the lower portion of the slide insert 53 can sufficiently come into contact with the bladder (expandable bag) 51 when it is inflated. Further, pressure oil is introduced into the bladder 51 through a hydraulic pressure inlet 46 formed in the bottom plate 42 of the cylinder 44, and the pressing force F generated in the bladder 51 by the pressure oil is smoothly applied to the slide insert 53. The clamping force between the fixed platen 52 and the movable platen 54 is applied.
[0022]
Moreover, as the bladder 51 used in the present embodiment, for example, a flexible material excellent in oil resistance such as nitrile rubber, acrylic rubber, silicone rubber, and fluorine rubber is preferable, and the thickness is the diameter of the slide insert 53. For example, 2 to 5 mm is preferable. Further, in the present embodiment, the compact bladder 51 is provided in contact with the stationary platen 52 and this pressure oil is enclosed in the bladder 51, so that the stationary mold 82 is interposed via the mold mounting plate 56. In addition, a mold clamping force can be applied to the mold clamping mold 82.
[0023]
In particular, when pressure oil is supplied to or discharged from the bladder 51, as shown in FIG. 12, in the case of the hermetic bag 16 according to the prior art, part of the corners of the hermetic bag 16 is fixed platen as the bag expands and contracts. 8 and the ram 14 will enter the gap. Under such a phenomenon, the sealing bag 16 in the portion that has entered the gap between the fixed platen 8 and the ram 14 gradually becomes weak due to expansion and contraction, and the injection molding machine Or it could be damaged during operation of the die-casting machine.
In order to eliminate such inconvenience, in the present invention, as shown in FIG. 3, as shown in FIG. 3, a slide insert as a protective material is provided so that the corner portion of the bladder 51 does not enter the gap between the cylinder 44 and the slide insert 53. The outer peripheral portion of the 53 on the side of the bladder 51 is engraved in an L-shaped cross section, and a piston ring 48 and a backup ring 49 are inserted and arranged in a superimposed manner.
[0024]
In the present embodiment, as the piston ring 48, for example, a ring-shaped one knitted with tetrafluoroethylene fibers is disposed adjacent to the bladder 51. When such a piston ring 48 is used, before the pressure oil is introduced into the bladder 51 as shown in FIG. 3A, the bladder 51 is not expanded, so that the piston ring 48 and the slide insert 53 or Clearances L0, L1, L2, L3, and L4 between the bladders 51 are held.
[0025]
Further, as shown in FIG. 3B, when pressure oil is introduced into the bladder 51, the bladder 51 expands and presses the piston ring 48, and the clearance L0 between the slide insert 53 and the bladder 51 is zero. At the same time, the clearances L1, L2, L3, and L4 on the upper, lower, left, and right sides of the piston ring 48 are also zero. When such a ring-shaped material knitted with Teflon fibers is used, the gap 51 is eliminated due to the expansion of the bladder 51, so that a part of the bladder 51 is expanded and contracted and finally the bladder 51 is damaged. Disappear. Further, since the piston ring 48 is flexible, there is an advantage that the rubber bladder 51 is hardly damaged.
[0026]
As shown in FIG. 4, if a piston ring 48a as a protective material having reinforcing portions 48b at four corners or one corner is used, the piston ring 48a is prevented from being deformed, so that the sealing degree of the clearances L1 to L4 is increased. At the same time, it is possible to prevent the corner portion of the piston ring 48a from entering the gap S1 between the cylinder 44 and the slide insert 53, and to protect the piston ring 48a from being damaged. Enables smooth forward and backward movement. In addition, the arrangement of the backup ring 49 can be omitted, and the cost can be reduced.
[0027]
Operations of the injection molding machine and the die casting machine configured as described above will be described below.
[0028]
When the servo motor 71 provided on the fixed platen 52 is driven from the mold open state, the ball screw member 72 is rotated. The movable mold 84 approaches the fixed mold 82, the movable mold 84 comes into contact with the fixed mold 82, and the mold is closed. Under such a mold closing state, each ring groove 61b meshes with the half nut 55. Accordingly, when the mold is replaced, the mold thickness (die height) changes. Therefore, when the servo motor 69 is rotated prior to molding, each tie rod 61 is connected via a belt stretched between the tie rod nut rotating members 63. The length of the threaded portion 61a that moves in the axial direction and protrudes outside the fixed platen 52 changes.
[0029]
Next, when pressure oil is introduced into the bladder 51 from the oil pressure introduction port 46 via the pump 88, the bladder 51 expands and presses the slide insert 53 toward the mold attachment plate 56, and the mold clamping is performed. . In the present embodiment, as shown in FIG. 3, to prevent damage by partially inserted into the gap between the cylinder 44 and the slide insert 52 repeating operation of bladder 51 with the expansion of the bladder 51, between each gap L1 , L2, L3, and L4, the soft piston ring 48 closes the gap. Further, the hard backup ring 49 is pressed and deformed so that the deformed piston ring 48 does not block the gap S1 between the cylinder 44 and the slide insert 53. In the present embodiment, the shape of the bladder 51 is not limited, and the ring shape shown in FIG. 7 may be used. Alternatively, a plurality of circular bladders shown in FIG. 8 may be mounted.
[0030]
When the mold clamping for a predetermined time is completed, the pressure of the bladder 51 is released, the pressure oil in the bladder 51 is released, the applied mold clamping force becomes zero, and the slide insert 53 that presses the mold mounting plate 56. Returns to its original position. Thereafter, each ring groove 61b is disengaged from the half nut 55. When the fixed mold 82 and the movable mold 84 are closed, the ball screw member 72 that drives the servo motor 71 is rotated, and the movable mold 84 is retracted to the initial position and the mold is opened. Thereafter, the product is taken out and one cycle is completed.
In the above-described embodiment, the slide 51 is protruded by forming the inside of the bladder 51 into a hollow hydraulic chamber, introducing pressure oil from the oil pressure introduction port 46, and expanding the bladder 51. The pressure plate 56 is applied with pressure to obtain a clamping force between the fixed and movable molds 82 and 84, but the bladder 51 has an outer shape in the same shape as the bladder hollow chamber in advance. Also in the embodiment in which the child is loaded, and the pressure oil is supplied into the bladder 51 through the oil passage passing through the core and discharged, the flexible protective member is provided in the same manner as in the above embodiment. It is easy to arrange the piston ring 48 and the backup ring 49 to be formed to protect the bladder corner when the bladder 51 is inflated, and to facilitate the forward and backward movement of the slide insert 53. I understand.
[0031]
【The invention's effect】
As described above, in the present invention, a movable platen having a movable mold and arranged to be movable forward and backward, a fixed platen having a fixed mold arranged to face the movable platen, A mold mounting plate for mounting the fixed mold between the fixed platen and the fixed mold, a slide insert disposed loosely between the concave plate and the mold mounting plate engraved in the fixed platen, A hollow piston made of a stretchable material that clamps the mold between the recess of the slide nest and the fixed platen, and a soft piston with a recess space near the outer periphery of the slide nest By inserting a seal member consisting of a ring and a rigid backup ring, the overall length of the device is shortened, and the bladder is not inserted into the gap when expanding or contracting with the supply and discharge of pressure oil. Endurance Greatly improves the reliability of the device is greatly improved.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a pressure mechanism of a mold clamping device.
FIG. 2 is an enlarged cross-sectional view of a pressure mechanism of the mold clamping device.
FIGS. 3A and 3B are explanatory views showing a state where a bladder is protected by a seal member, where FIG. 3A shows a state before the bladder is pressurized by pressure oil supply, and FIG. 3B shows a state after the pressure is applied; FIG.
4 is an explanatory view showing a protected state of a bladder by a seal member similar to FIG. 3. FIG.
FIG. 5 is an overall configuration diagram of a mold clamping device according to an embodiment of the present invention.
FIG. 6 is a pressure oil supply device diagram to a bladder.
7 is a front view showing a ring-shaped bladder as seen from AA in FIG. 5. FIG.
8 is a front view showing a state in which a plurality of circular bladders as viewed from AA in FIG. 5 are mounted. FIG.
FIG. 9 is an overall view of a conventional direct pressure type mold clamping device.
FIG. 10 is an overall view of a mold clamping device in which a hermetic bag is incorporated in a conventional fixed platen.
FIG. 11 is a cross-sectional view of a pressure mechanism of a conventional mold clamping device.
FIGS. 12A and 12B are partially enlarged cross-sectional views illustrating a process in which a sealed bag enters a gap in a conventional pressurizing mechanism. FIGS.
[Explanation of symbols]
40 ... Pressure mechanism 42 of mold clamping device ... Bottom plate 44 ... Cylinder 46 ... Hydraulic inlet 47 ... Outer peripheral recess 48 ... Piston ring (protective material)
48 b ... Reinforcing part 49 ... Backup ring 50 ... Clamping device 51 ... Bladder 52 ... Fixed platen 52a ... Cylinder hole 53 ... Slide insert 54 ... Movable platen 54a ... Through hole 55 ... Half nut 56 ... Mold mounting plate 57 ... Compression coil spring 59 ... Machine base 61 ... Tie rod 61a ... Threaded portion 61b ... Ring groove 63 ... Tie rod nut rotating member 64 ... Tie rod nut retainer fitting 67 ... Detent fitting 68 ... Nut cylinder 69 ... Servo motor 71 ... Servo motor 72 ... Ball Screw member 72a ... Screw portion 73 ... Ball nut 82 ... Fixed die 84 ... Movable die 88 ... Pump 100 ... Oil tank

Claims (3)

A movable platen having a movable mold and disposed so as to be movable forward and backward, a fixed platen having a fixed mold disposed opposite to the movable platen, and a fixed mold between the fixed platen and the fixed mold A mold mounting plate for mounting, a cylinder fitted in a recess provided in the fixed platen, a slide member loosely disposed in the cylinder and projectable toward the mold mounting plate, and the slide An expansion / contraction bag disposed between the member and the bottom plate of the cylinder and capable of being clamped between the movable and fixed molds via the slide member by expanding and contracting according to pressure supply / discharge, and the slide member loaded in the space which is recessed in the outer periphery in the vicinity of the end portion, by being pressed by the expansion force of the stretchable bag during inflation of the elastic bag, capable of closing flexible protecting clearance of the slide member and the cylinder Element ,
A pressurizing mechanism for a mold clamping device, comprising: 2. The pressurizing mechanism for a mold clamping device according to claim 1, wherein the flexible protection member is formed as a soft piston ring made of a fiber material having a hard reinforcing portion at a corner of a square cross section.   2. The pressurizing mechanism for a mold clamping device according to claim 1, wherein the flexible protection member is formed by superposing a hard backup ring and a soft piston ring adjacent to the elastic bag.

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