JPH0314609B2 - - 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 the size of the die and speed up its operation, thereby reducing manufacturing and operating costs, the moving die plate is moved using a boost recynder instead of moving and clamping the die 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, pressure 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 toward 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 be 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 rotated 90 degrees, and after insertion is completed, the mold is rotated again at 90 degrees 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 been proposed to provide a tie bar pulling device to make it easier to pull out the tie bars and replace 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 a means for engaging and coupling and fixing the tie bar and the movable die plate around the opening of the tie bar insertion hole provided in the movable die plate, and to By providing a replaceable stopper on the holder, the threaded part of the tie bar can be reliably engaged with the half nut due to the contact between the tie bar and the stopper, which also makes it easier to replace the mold. It is an object of the present invention to provide a mold clamping device that can easily and quickly adjust the mold thickness at the time of molding, 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 relative to the fixed die plate; A mold clamping device comprising a tie bar that is coupled and fixed to the movable die plate immediately before the plate approaches the fixed die plate and the movable die is closed, and performs mold clamping after the mold is closed, A locking means for locking the tie bar inserted into the tie bar insertion hole provided in the movable die plate to the movable die plate, and a mold clamp for tightening the movable die plate and the fixed die plate that are coupled and fixed by the locking means. and the locking means includes a threaded portion formed on a portion of the tie bar;
A stopper is fixed on the surface opposite to the mold mounting surface of the movable die plate so as to come into contact with the tip of the tie bar that has passed through the tie bar insertion hole, and a movable die is attached to the threaded portion of the tie bar positioned by the stopper. It is characterized by comprising a half nut movably provided on the opposite surface of the plate to the mold mounting surface substantially perpendicularly to the axis of the tie bar.

That is, in the mold clamping device according to the present invention,
As a means of locking the moving die plate and tie bar,
A stopper is provided on the surface of the movable die plate opposite to the mold mounting surface to lock the tip of the tie bar.

In this case, the stopper is formed of a cylindrical body with one end closed, and is arranged in the opening on the surface opposite to the mold mounting surface of the movable die plate in order to abut the tip of the tie bar that has passed through the insertion hole on the closed end surface. If it is provided in a replaceable manner, it is suitable for adjusting the mold thickness.

Therefore, when connecting and fixing the tie bar and the movable die plate, a half nut is movably provided on the surface of the movable die plate opposite to the mold mounting surface approximately perpendicular to the axis of the tie bar insertion hole, and a part of the tie bar is attached to the movable die plate. If the tie bar is provided with a threaded portion that meshes with the half nut, the axial dimension of the tie bar is positioned by contact with the stopper, so that the threaded portion of the tie bar and the half nut can easily mesh with each other.

[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.

2 and 3 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 a portion of the tie bar 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 fixed mold 56 of the movable die plate 58 is attached. 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.

Therefore, in one embodiment of the mold clamping device according to the present invention, as shown in FIG. The insertion hole 74 is set to be slightly spaced apart from the insertion hole 74 of the movable die plate 58, and is located on the opposite side of the movable die plate 58 to the surface on which the movable mold 56 is attached.
Stoppers 96 having different axial dimensions are fixed to the openings of the holes. This stopper 96 is made of a cylindrical body with one end closed, and is configured so that the tip of the tie bar 64 comes into contact with the closed end surface 98. Note that in this embodiment as well, the stopper 9
A half nut 76 is provided on the outer periphery of the tie bar 6 so as to be movable forward and backward via a moving means 80 as appropriate, and is configured to engage with a threaded portion 72 provided on the tie bar 64. With this configuration, the tie bars 64 and the movable die plate 58 are coupled and fixed during mold clamping, and smooth mold clamping can be achieved.
For example, in order to position the tie bar 64 in the axial direction, there is a method in which a plurality of grooves are formed in the tie bar 64 and a stop ring is attached to the groove, and the tie bar 64 is brought into contact with the mold mounting surface of the movable mold 58 for positioning.
In particular, according to this embodiment, since the attachment of the stop ring to the tie bar 64 is omitted, it is possible to maintain sufficient strength even if the shaft diameter of the tie bar 64 is made thinner, which contributes to miniaturization of the device. be able to.

In this case, at the standby position of the tie bar 64,
Immediately before the movable die plate 58 starts moving and the fixed die 52 and the movable die 56 complete mold closing, the tip of the tie bar 64 that has passed through the insertion hole 74 of the movable die plate 58 comes into contact with the stopper 96. The threaded portion 72 of the tie bar thus positioned is positioned such that it can be engaged with a half nut 76 provided on the movable die plate. In addition, half nut 7
As the moving means 6, a hydraulic cylinder or other drive mechanism can be appropriately employed.

Further, the hydraulic cylinder 60 for moving the tie bar 64 when clamping the mold is configured to move the tie bar 64.
If the design is designed to ensure a sufficiently large stroke length, the mold mounting surface of the movable die plate 58 and the tie bar 64 can be moved sufficiently toward the fixed die plate 54 with the movable die plate 56 in the mold open state. The distance between the mold and the tip of the mold is considerably large, making it easy to replace the mold. In other words, if the distance between the mold mounting surface of the movable die plate 58 and the tip of the tie bar 64 is sufficiently spaced, the mold can be taken in and out from the side of the molding machine, and the mold can be lifted higher than necessary. This eliminates the need for mold replacement work, simplifies the process of mold replacement work, and significantly reduces the installation space of the molding machine, as well as reduces equipment costs and operating costs.

Furthermore, as shown in FIGS. 2 and 3, the tie bar 6 is moved by a pair of hydraulic cylinders 60.
4 is configured to be integrally connected at the rear.

That is, a rod 88 is connected to the internal piston 62 provided in the hydraulic cylinder 60 of the mold clamping device in the opposite direction to the tie bar 64, and is caused to protrude outside the fixed die plate 54. 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 fixed die plate 54
It is preferable to connect the ends of the rods 88 that protrude from each other with a connecting rod 90, because synchronization of the movement of the internal pistons 62 in each hydraulic cylinder 60 can be easily achieved.

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 mold closing between the mold 52 and the movable mold 56 is completed, the tip of the tie bar 64 that has passed through the insertion hole 74 of the movable die plate 58 passes through the insertion hole on the side opposite to the surface on which the movable mold 56 is attached. It comes into contact with a stopper 96 fixed to the opening of 74 (see FIG. 3).

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 Figure 3). As a result, the tie bar 64 is
As with the conventional mold clamping device, the coupling and fixing with the movable die plate 58 can be easily achieved. Next, when pressure oil is supplied to one oil chamber 86 of the hydraulic cylinder 60 provided in the fixed die plate 54, the movable die plate 58 is moved toward the fixed die plate 54 by directly moving the tie bar 64. , it is possible to achieve mold clamping between the fixed mold 52 and the movable mold 56.

Further, in this embodiment, mold thickness adjustment when replacing the mold can be easily achieved by attaching stoppers 96 having different axial dimensions l so as to be replaceable.

In addition, in the above-mentioned embodiment, a boost cylinder consisting of a hydraulic cylinder was used as a driving means for closing the mold, and a hydraulic cylinder was used as a 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.

〔Effect of the invention〕

As is clear from the embodiments described above, the mold clamping device according to the present invention has a stopper replaceably provided on the mold mounting surface of the movable die plate.
The threaded part of the tie bar is positioned relative to the half nut by the contact between the tie bar and the stopper, ensuring mutual engagement.As the movable die plate moves during mold clamping, the movable die plate is directly attached to the tie bar. Since it is configured to be locked and fixed, the tie bars are configured to be relatively short, making the device more compact and reducing weight, and further allowing the tie bars to be significantly retracted relative to the moving die plate. This makes it possible to maintain a sufficient distance between the molds and the molds to facilitate mold replacement work.

In addition, the device of the present invention can set the length of the tie bar shorter than the conventional mold clamping device, and eliminates all the support plates and other components that were always located outside the moving 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, each tie bar is configured to be completely separated from the movable die plate, so maintenance work such as replacing the bearing member and shaft seal member provided at the tie bar bearing part 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 use a hydraulic servo mechanism to control the position.

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 the drawing]

FIG. 1 is a longitudinal 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 FIG. 3 is a mold clamping device. FIG. 2 is a plan sectional view showing the device in a mold-clamped state. 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, 80...means of transportation, 84
...oil room, 86...oil room, 88...rod, 90
...Connecting rod, 91...Tie bar guide, 96...
Stoppa, 98...Occluded surface.

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 plate is closed and 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 die plate to the movable die plate; and a mold clamping means for tightening the movable die plate and the fixed die plate that are coupled and fixed by the locking means. The locking means includes a threaded portion formed on a portion of the tie bar;
A stopper is fixed on the surface opposite to the mold mounting surface of the movable die plate so as to come into contact with the tip of the tie bar that has passed through the tie bar insertion hole, and a movable die is attached to the threaded portion of the tie bar positioned by the stopper. A mold clamping device comprising: a half nut movably provided on the opposite surface of the plate to the mold mounting surface substantially perpendicularly to the axis of the tie bar. 2. In the mold clamping device according to claim 1, the stopper is constituted by a cylindrical body with one end closed, and the stopper is formed of a movable die plate in order to abut the tip of the tie bar passing through the insertion hole on the closed end surface. A mold clamping device replaceably provided in the opening on the opposite surface of the mold mounting surface.