JPH029924B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] This invention relates to a mold clamping device for an injection molding machine or a die casting machine.

[Prior art and its problems]

Generally, in mold clamping devices such as injection molding machines,
In order to prevent the mold from opening due to the pressure inside the mold during injection, a large mold clamping force is required during mold clamping.On the other hand, after the molded product has solidified, the mold is quickly closed by the stroke necessary to eject it. The operation of opening and opening the mold requires a high speed of opening and closing the mold in order to ensure a sufficient stroke to take out the molded product and to improve productivity.

However, in recent years, demand for injection molding machines and the like has shown a tendency to increase in size, and for this reason, hydraulic mold clamping devices have reduced machine weight and installation area, and have a large capacity, as well as hydraulic drive sources. In order to reduce manufacturing costs and operating costs by reducing the size of the die and increasing its operation speed, the movable die plate is moved by a push cylinder instead of moving and clamping the mold using a single cylinder. A method has been implemented in which the mold is opened and closed, and the movable die plate is strongly pressed against the fixed die plate by a separately provided mold clamping cylinder (hydraulic cylinder) to clamp the mold.

FIG. 1 is a longitudinal sectional view showing a typical configuration example of a conventional injection molding machine. That is, in FIG. 1, reference numeral 10 indicates a support frame, and a fixed die plate 14 to which a fixed mold 12 is attached is fixed to one end of the support frame 10. Further, at the other end of the support frame 10, a movable die plate 18 to which a movable die 16 is attached is slidably mounted opposite to the fixed die plate 14. The fixed die plate 14 includes a plurality of hydraulic cylinders 2.
0, and a tie bar 24 is provided extending from one side of the internal piston 22 of each of these hydraulic cylinders 20 toward the movable die plate. These tie bars 24 pass through the insertion holes 36 of the movable die plates 18 facing each other, and their tips are connected and fixed to the support plate 26 . A boost cylinder 28 is fixed to one side of the fixed die plate 14, and the tip of a rod 32 connected to the internal piston 30 of the boost cylinder 28 is connected to the movable die plate 1.
8 as appropriate. Also, tie bar 24
The movable die plate 18 is provided with a threaded portion 34 on a portion thereof, and an insertion hole 36 through which the tie bar 24 is inserted is provided on the side opposite to the surface on which the movable mold 16 is attached. Threaded part 3
4, insert the half nut 38 into the insertion hole 36.
provided so as to be movable in a direction substantially perpendicular to the axis of the In this way, a shaft 40 that passes through the support plate 26 is protruded from the center of the movable die plate 18 provided with the half nut 38, and a stop ring 42 for the support plate 26 is positioned at the tip of this shaft 40. Provided to be adjustable. That is, a plurality of circumferential grooves 44 for changing the position of the stop ring 42 are appropriately provided at the tip of the shaft 40.

The conventional mold clamping device configured as described above first moves the movable die plate 18 toward the fixed die plate 14 by supplying pressure oil to one oil chamber 46 of the boost cylinder 28 when closing the mold. In this way, the fixed mold 12 and the movable mold 1
Immediately before the mold closing with 6 is completed, a stop ring 42 positioned on a shaft 40 projecting from the movable die plate 18 engages with the support plate 26. At this time, a half nut 38 provided on the movable die plate 18 is moved in a direction substantially perpendicular to the axis of the insertion hole 36, and is engaged with a threaded portion 34 formed on a part of the tie bar 24. Therefore, in this case,
The tie bar 24 is integrally connected to the movable die plate 18 by the half nut 38. Next, pressurized oil is supplied to one oil chamber 48 of the hydraulic cylinder 20 provided in the fixed die plate 14, and the tie bar 24 is moved directly to the fixed die plate side, thereby moving the movable die plate 18 to the fixed die plate 14 side. Move the fixed mold 12 and the movable mold 1
6 can be achieved.

However, today's injection molding machines, etc. tend to become larger and larger, and there are many demands for high-mix, low-volume production, so it is necessary to make them lighter and smaller, as well as to facilitate mold replacement and reduce costs. Since then, there has been a demand for a mold clamping device with even better operability. In other words, the mold replacement work in the conventional equipment described above is generally carried out by suspending the mold using an overhead crane, lifting it above the molding machine, and then hanging it between tie bars and attaching it to the molding machine. be.
For this reason, a building in which a particularly large molding machine is installed requires a high ceiling, which has the disadvantage of increasing equipment costs. In addition, when the dimensions of the mold are larger than the spacing between parallel tie bars, the mold is inserted from above with the mold turned 90 degrees, and after insertion is completed, the mold is turned 90 degrees again and installed. Not only does it require a lot of man-hours, but it also has the disadvantage of being very dangerous. In order to overcome these problems, it has also been proposed to provide a tie bar pulling device to facilitate pulling out the tie bars and replacing the mold, but this type of device is extremely expensive. Therefore, there is a need for a device that can easily pull out tie bars using a standard mechanism.

In addition, in the conventional device, the tie bar 24, the support plate 2
6 and a shaft 40 with a stop ring 42 that engages with the mold thickness adjustment mechanism protrudes from the main body of the device, requiring a large installation area. It is necessary to raise the height of the crane to lift the equipment, and the factory building must be made sufficiently high. Furthermore, there is a need to further reduce the installation area and to make it possible to install large machines within the existing building. There is.

Furthermore, with conventional equipment, mold thickness must be adjusted every time the thickness of the mold changes as the mold is replaced, and for this reason, systems incorporating automatic mold thickness adjustment devices have also been implemented. However, since the manufacturing cost increases, there is a need for an apparatus that can smoothly adjust the mold thickness at low cost. Moreover, it is required to increase the applicability of the entire device to automation and improve its performance, as well as to reduce the total weight of the device and realize miniaturization, thereby further reducing the manufacturing cost and operating cost of the device. ing.

[Purpose of the invention]

An object of the present invention is to provide means for engaging and coupling and fixing the tie bars and the movable die plate around the openings of the tie bar insertion holes provided in the movable die plate. This allows for a substantial reduction in the size of the tie bars, which reduces the installation area, and also simplifies mold replacement work and facilitates mold thickness adjustment during mold replacement. It is an object of the present invention to provide a mold clamping device that can easily and quickly achieve the above-mentioned results, and can easily realize reductions in manufacturing costs and operating costs.

[Structure of the invention]

A mold clamping device according to the present invention includes: a fixed die plate that holds a fixed mold; a movable die plate that holds a movable mold; a means for moving the movable die plate forward and backward with respect to the fixed die plate; In the mold clamping device, the plate approaches the fixed die plate, and the fixed die and the movable die are connected and fixed to the movable die plate immediately before the mold is closed, and are configured with a tie bar that performs mold clamping after the mold is closed. A locking means for locking a tie bar inserted into a tie bar insertion hole provided in the movable die plate to the movable die plate, and a movable die plate and the fixed die plate are connected via the tie bar locked by the locking means. and a mold clamping means for tightening, and the locking means includes a stop ring provided on the tie bar so that the position can be adjusted freely so as to lock with the mold mounting surface side of the movable die plate, and a stop ring on the opposite side of the mold mounting surface of the movable die plate. A half nut is provided on the top of the tie bar so as to be movable approximately perpendicularly to the axis of the tie bar insertion hole, and a threaded portion that engages with the half nut is provided in a part of the tie bar to move the tie bar. It is characterized in that the tie bar and the movable die plate are connected and fixed by engagement with a half nut after being locked to the side and positioned.

Further, in the mold clamping device of the present invention, the end of the tie bar is held in a state separated from the opening of the tie bar insertion hole of the movable die plate when the movable mold and the fixed mold are in the maximum mold open state. It is suitable if

As an alternative, the ends of the tie bars may be configured to be inserted and held in the tie bar insertion holes of the movable die plate when the movable mold and the fixed mold are in the maximum mold open state, or A guide tube is attached to the opening of the tie bar insertion hole on the mold mounting surface, and the end of the tie bar is configured to be inserted and held in the guide tube when the movable mold and the fixed mold are in a maximum mold open state. For example, the movement of the movable die plate with respect to the tie bars can be further stabilized.

Furthermore, in the mold clamping device of the present invention, it is preferable to use a hydraulic cylinder as a driving means for moving the tie bars for clamping the mold. Therefore, it is preferable to extend a rod to the other side of the internal piston of the hydraulic cylinder to which one end of the tie bar is fixed, and to project this rod to the outside of the hydraulic cylinder.
In this case, the ends of the rods protruding from the hydraulic cylinder can also be connected and fixed to each other by means of a connecting rod.

Note that instead of extending the rod to the other side of the internal piston as described above, it is also possible to provide a tie bar guide that surrounds and holds the tie bar projecting from the fixed die plate.

Furthermore, by providing a part of the hydraulic cylinder to be replaceable, the stroke length can be set variably. In this case, by setting the stroke of one or more hydraulic cylinders, especially one of the upper tie bars, to be longer than the other hydraulic cylinders, it is possible to increase the amount of movement of the tie bars and facilitate mold replacement work. can.

[Embodiments of the invention]

Next, regarding an example of the mold clamping device according to the present invention,
A detailed description will be given below with reference to the accompanying drawings.

FIG. 2 to FIG. 6 show an embodiment of a mold clamping device according to the present invention. In the mold clamping device of this embodiment, reference numeral 50 indicates a support frame, a fixed die plate 54 having a fixed mold 52 attached thereto is fixed on one end of the support frame 50, and A movable die plate 58 to which a movable mold 56 is attached is slidably placed opposite the fixed die plate 54. The fixed die plate 54 has a plurality of die plates (four in this embodiment).
Hydraulic cylinders 60 (base) are provided, and tie bars 64 are provided extending in the direction of the movable die plate 58 from the surfaces of the internal pistons 62 of these hydraulic cylinders 60 on the movable die plate 58 side. Further, a boost cylinder 6 is mounted on one side of the fixed die plate 54.
6 is fixed, and the tip of a rod 70 connected to the internal piston 68 of this boost cylinder 66 is appropriately fixed to one side of the movable die plate 58. Further, a threaded portion 72 is formed in each of the tie bars 64, and an insertion hole 74 through which the tie bar 64 is inserted is formed on the side opposite to the surface on which the movable mold 56 is attached to the movable die plate 58. A half nut 76 that engages with the threaded portion 72 of the tie bar 64
is provided so as to be movable in a direction substantially perpendicular to the axis of the insertion hole 74.

The above configuration is the same as that of a conventional mold clamping device. However, in the present invention, the support plate 26 and its guide shaft 40, which are commonly provided in conventional mold clamping devices, are removed, and the tie bar 6 is inserted into the tie bar insertion hole 74 provided in the movable die plate 58.
The movable die plate 58 in the insertion position relationship of 4
By providing means for directly locking the tie bars 64 and the tie bars 64, the tie bars 64 are properly locked at the same time as they pass through the insertion holes 74 of the movable die plate 58 during mold clamping.

For this reason, in one embodiment of the mold clamping device according to the present invention, as shown in FIG. This tie bar 6
A stop ring 78 is provided on a part of 4 so that the position can be adjusted freely. In this case, in order to smoothly align the insertion holes 74 of the movable die plate 58 and the tie bars 64, it is preferable to expand the opening edge of the insertion holes 74 in a tapered shape. Also, tie bar 6
In the standby state of step 4, just before the movable die plate 58 moves and the fixed die 52 and the movable die 56 complete mold closing, the stop ring 78 provided on the tie bar 64 closes the insertion hole 7 of the movable die plate 58.
4 and positioned so that the threaded portion 72 provided on the tie bar 64 and the half nut 76 provided on the movable die plate 58 mesh with each other. Note that as the means for moving the half nut 76, a fluid pressure cylinder or other drive mechanism can be appropriately employed.

Further, as shown in FIGS. 3 and 4, a guide tube 82 is provided to extend into the opening of the insertion hole 74 on the mold mounting surface side of the movable die plate 58, so that the movable die plate 58 is in the open state. The guide tube 82 is configured to insert and hold the tip of the tie bar 64 through the guide tube 82. With this configuration, the operation of reinserting the tie bar 64 into the insertion hole 74 of the movable die plate 58 when the mold is closed is substantially eliminated, and the operation is stabilized. In this case, the locking position of the stop ring 78 with respect to the movable die plate 58 is the open end of the guide tube 82, so the tie bar 6
It is necessary to adjust the relative position of the threaded portion 72 of No. 4 and the stop ring 78 as appropriate. In particular, if the guide tube 82 is provided in a removable manner, it is advantageous for the mold replacement work to be described later. Furthermore, if the hydraulic cylinder 60 for moving the tie bar 64 during mold clamping is designed to ensure a sufficiently large stroke length of the tie bar 64, the tie bar 64 can be moved toward the fixed die plate 54 side with the movable die plate 56 in the mold open state. By sufficiently moving the movable die plate 58 to the end portion of the tie bar 64, the distance between the die mounting surface of the movable die plate 58 and the tip of the tie bar 64 becomes considerably large, and the die replacement work can be facilitated. That is, the mold mounting surface of the movable die plate 58 and the tie bar 64
If the distance between the tip and the tip of the mold can be made sufficient, it will be possible to insert and remove the mold from the side of the molding machine, eliminating the need to lift the mold higher than necessary and simplifying the mold replacement process. Along with this, it is possible to realize a significant reduction in the installation space of the molding machine, and also to achieve reductions in equipment costs and operating costs.

The mold clamping device according to this embodiment configured as described above moves the movable die plate 58 toward the fixed die plate 54 and fixes it by supplying pressure oil to one oil chamber 84 of the boost cylinder 66 when closing the mold. Immediately before the closing of the mold 52 and the movable mold 56 is completed, the stop ring 78 provided on the tie bar 64 engages with the open end of the guide tube 82 provided in the insertion hole 74 of the movable die plate 58 (the first (See Figure 4). At this time, if the half nut 76 provided on the movable die plate 58 is moved by the moving means 80 in a direction substantially perpendicular to the axis of the insertion hole 74, it can be engaged with the threaded portion 72 formed on the tie bar 64 ( (See Figures 4 and 5).
As a result, the tie bars 64 can be easily coupled and fixed to the movable die plate 58 as in the conventional mold clamping device. Next, one oil chamber 8 of the hydraulic cylinder 60 provided on the fixed die plate 54
6, the movable die plate 58 is moved toward the fixed die plate 54 by directly moving the tie bar 64, and the fixed die 52
It is possible to achieve mold clamping between the movable mold 56 and the movable mold 56.

In the embodiment shown in FIG. 6, the guide tube 82 is omitted and the tips of the tie bars 64 are kept inserted into the insertion holes 74 of the movable die plate 58 when the mold is opened. The other configurations are completely the same as those of the embodiment described above, and the same reference numerals are given to the same components, and detailed explanation thereof will be omitted. Therefore, even with the mold clamping device having such a configuration, it is possible to realize mold clamping work having exactly the same advantages as in the embodiment described above.

7 and 8 show another embodiment of the mold clamping device according to the present invention. That is, in this embodiment, a rod 88 is connected to the internal piston 62 provided in the hydraulic cylinder 60 of the mold clamping device of the above-described embodiment in the opposite direction to the tie bar 64, and is connected to the outside of the fixed die plate 54. It is something that stands out. With this configuration, the tie bar 64 is substantially supported at three points, and the state in which the tie bar 64 is held can be stabilized. Furthermore, in the mold clamping device of this embodiment, the ends of the rods 88 protruding from the fixed die plate 54 are connected to each other by a connecting rod 90, thereby synchronizing the movement of the internal pistons 62 in each hydraulic cylinder 60. This is suitable because it can be easily achieved.

In addition, as a means for supporting the tie bar 64 at three points, the internal piston 6 is used as described above.
Instead of connecting the rod 88 in the opposite direction to the tie bar 64 with respect to the fixed die plate 54, the tie bar 64 protruding from the fixed die plate 54 is surrounded and held.
It is also possible to provide tie bar guides 91 (indicated by broken lines in FIG. 2) on the fixed die plate 54.

FIG. 9 shows still another modification of the mold clamping device according to the present invention, and shows the above-mentioned FIGS. 7 and 8.
Tie bar 6 used in the mold clamping device of the example shown in the figure
4, the threaded portion 72 is sufficiently extended in the axial direction, and a plurality of circumferential grooves 92 are provided at appropriate intervals in the axial direction for attaching the stop ring 78 in an adjustable manner. With this configuration, even if the dimensions of the mold change due to mold replacement, it is possible to easily adjust the mold thickness to properly position the movable die plate 58 and the tie bar 64 to engage and to connect and fix them. Can be done. In addition, in this embodiment, the cylinder member 94 of the fixed die plate 54 constituting the hydraulic cylinder 60 is configured to be attached interchangeably with cylinder members of different sizes so that the stroke length of the internal piston 62 can be adjusted. By doing so, the stroke adjustment accompanying the above-mentioned mold thickness adjustment of the tie bar 64 can be easily achieved, which is preferable. Although FIG. 9 is shown as a modification of the embodiment shown in FIGS. 7 and 8, it is understood that this embodiment can also be applied to the embodiments shown in FIGS. 2 to 6. Of course.

In addition, in the above-mentioned embodiment, a boost cylinder consisting of a hydraulic cylinder was used as the driving means for closing the mold, and a hydraulic cylinder was used as the driving means for clamping the mold. Instead of the drive means, it is also possible to use a drive means such as a motor or a servo motor. Furthermore, the embodiments shown in FIGS. 2 to 9 described above are as follows:
It is also possible to use a partial combination of each embodiment.

〔Effect of the invention〕

As is clear from the various embodiments described above, the mold clamping device according to the present invention is configured such that as the movable die plate moves during mold clamping, the movable die plate is directly engaged with the tie bar to be coupled and fixed. Therefore, the size of the tie bars is made relatively short to reduce the size and weight of the equipment, and furthermore, the tie bars can be set back significantly with respect to the moving die plate, and the distance between them is maintained sufficiently to increase the size of the die. Mold replacement work can be facilitated.

In addition, in the device of the present invention, the hydraulic cylinder that moves the tie bar has a sufficiently long stroke length, making it easy to replace the mold as described above, and to adjust the position of the stop ring. This has the advantage of being able to quickly adjust the mold thickness when replacing the mold.

In particular, the device of the present invention allows the length of the tie bars to be set shorter than that of conventional mold clamping devices, and eliminates all the support plates and other components that were always located outside the movable die plate as in the conventional device. Since it can be omitted, the dimension in the moving direction of the movable die plate of the mold clamping device can be significantly reduced. In this case, the increase in the number of hydraulic cylinders on the fixed die plate side, the addition of rods for the internal pistons, and the addition of connecting rods to connect these rods to each other can be accommodated within the installation area occupied by the injection unit, so the installation area is reduced. It can be easily dealt with without any increase.

In addition, as mentioned above, since each tie bar is configured to be completely separated from the movable die plate, maintenance work such as replacing the bearing member and shaft seal member provided in the tie bar bearing portion of the hydraulic cylinder can be easily accomplished. Not only is it possible to replace the molds, but it is also easier to transport large molds into the existing building, improving work efficiency and significantly reducing operating costs.

Furthermore, in the device of the present invention, it is required to move the internal piston simultaneously and synchronously with a plurality of hydraulic cylinders during mold clamping.
In particular, for those without connecting rods, it is preferable to apply them to a hydraulic servo mechanism to perform position control.

Although the preferred embodiments of the present invention have been described above, it goes without saying that various design changes can be made without departing from the spirit of the present invention.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional view showing an example of the configuration of a conventional mold clamping device, FIG. 2 is a plan sectional view showing an embodiment of the mold clamping device according to the present invention in a mold open state, and FIGS.
The figures show other embodiments of the mold clamping device according to the present invention, and FIG. 3 is a plan sectional view of the mold in an open state;
FIG. 4 is a plan sectional view of the mold clamped state, FIG. 5 is a side view of the movable die plate seen from the end surface side, and FIG. 6 is a mold showing a modification of the mold clamping device shown in FIGS. 2 to 5. FIGS. 7 and 8 are plan sectional views of the mold opening state and mold clamping state, respectively, showing another embodiment of the mold clamping device according to the present invention, and FIG. 9 is a plan sectional view of the mold clamping device according to the present invention. FIG. 7 is an explanatory cross-sectional view of main parts showing a modification of the mold clamping device. 10...Support frame, 12...Fixed mold, 1
4...Fixed die plate, 16...Moving mold, 1
8...Moving die plate, 20...Hydraulic cylinder, 22...Internal piston, 24...Tie bar,
26...Support plate, 28...Boost cylinder, 3
0... Internal piston, 32... Rod, 34...
Threaded portion, 36... Insertion hole, 38... Half nut, 40... Shaft, 42... Stop ring, 44
...Circumferential groove, 46...Oil chamber, 48...Oil chamber, 50
...Support frame, 52...Fixed mold, 54...
Fixed die plate, 56...Movable mold, 58...
Moving die plate, 60...Hydraulic cylinder, 62
...Internal piston, 64...Tie bar, 66...
Boost cylinder, 68... Internal piston, 70
... Rod, 72 ... Thread part, 74 ... Insertion hole,
76... Half nut, 78... Stop spring, 80... Moving means, 82... Guide tube, 84
...oil room, 86...oil room, 88...rod, 90
...Connecting rod, 91...Tie bar guide, 92...
Circumferential groove for stop ring, 94...Cylinder member.

Claims (1)

[Scope of Claims] 1. A fixed die plate that holds a fixed mold, a movable die plate that holds a movable mold, means for moving the movable die plate forward and backward with respect to the fixed die plate, and the movable die plate A mold clamping device comprising a fixed mold that approaches a fixed die plate and a tie bar that is coupled and fixed to the movable die plate immediately before the movable die is closed and performs mold clamping after the mold is closed, wherein the movable die A locking means for locking a tie bar inserted into a tie bar insertion hole provided in the plate to a movable die plate, and a type for tightening the movable die plate and the fixed die plate via the tie bar locked by the locking means. and a stop ring provided on the tie bar so as to be adjustable in position so as to engage with the mold mounting surface of the movable die plate; A half nut is provided to be movable approximately perpendicularly to the axis of the tie bar insertion hole, and a threaded portion that engages with the half nut is provided in a part of the tie bar, so that the tie bar is attached to the mold mounting surface side of the movable die plate. A mold clamping device characterized in that the tie bar and the movable die plate are connected and fixed by engagement with a half nut after locking and positioning. 2. In the mold clamping device according to claim 1, the mold clamping means is composed of a hydraulic cylinder and an internal piston slidably inserted into the hydraulic cylinder, and a mold clamping device is provided on one side of the internal piston. A mold clamping device configured such that an end of a fixed tie bar is inserted and held in a tie bar insertion hole of a movable die plate when a movable mold and a fixed mold are in a maximum mold opening state. 3. In the mold clamping device according to claim 1, the mold clamping means is composed of a hydraulic cylinder and an internal piston slidably inserted into the hydraulic cylinder, and a mold clamping device is provided on one side of the internal piston. A mold clamping device configured such that an end of a fixed tie bar is held in a state separated from an opening of a tie bar insertion hole of a movable die plate when a movable mold and a fixed mold are in a maximum mold opening state. 4. In the mold clamping device according to claim 1, the mold clamping means includes a hydraulic cylinder and an internal piston slidably inserted into the hydraulic cylinder, while the mold of the movable die plate A guide tube is attached to the opening of the tie bar insertion hole on the mounting surface, and the end of the tie bar fixed to one side of the internal piston is inserted into the guide tube when the movable mold and the fixed mold are in the maximum mold open state. A mold clamping device configured to be held in place. 5. In the mold clamping device according to any one of claims 2 to 4, the tie bar is surrounded and held by a portion of the tie bar fixed to one side of the internal piston of the hydraulic cylinder that protrudes from the fixed die plate. A mold clamping device equipped with a tie bar guide. 6. In the mold clamping device according to any one of claims 2 to 4, a hydraulic cylinder having a tie bar fixed to one side has a rod extending from the other side of the internal piston, and this rod is hydraulically operated. A mold clamping device that protrudes outside the cylinder. 7. A mold clamping device according to claim 6, in which the ends of rods protruding from a hydraulic cylinder are connected and fixed to each other by a connecting rod. 8. The mold clamping device according to any one of claims 2 to 7, wherein a part of the hydraulic cylinder is replaceably provided so that the stroke length can be variably set. Device. 9. The mold clamping device according to any one of claims 2 to 8, wherein the stroke of one or more hydraulic cylinders is set longer than that of the other hydraulic cylinders.