JP3201866B2 - Mold clamping device and mold clamping method for injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold clamping device and a mold clamping method for an injection molding machine, and more particularly to a system in which mold clamping is performed by a mold clamping cylinder different from a mold opening / closing cylinder for moving and opening / closing a mold. And a mold clamping method.

[0002]

2. Description of the Related Art Generally, a mold clamping apparatus of this type includes a mold opening / closing cylinder c (only one is shown) for moving a moving plate b having a moving mold a attached thereto, as shown in FIGS. Separately, mold clamping cylinders e, f,
g and h, and the movable mold a
Abuts on the fixed mold j attached to the fixed die plate d, and then presses the respective tie bars m with the pressurized oil on each of the mold clamping side oil chambers k ... of each of the mold clamping cylinders e, f, g, h. The mold is pulled to the right in the figure to perform mold clamping.

Conventionally, in order to apply pressure oil to each of the clamping-side oil chambers k of the clamping cylinders e, f, g, and h, as shown in FIG. Via conduit r,
The structure is such that pressure oil is actuated by x, y, and z.

[0004]

However, since the hydraulic pressure source n is the same, the respective molds are not used due to, for example, an uneven load of a cavity (not shown) formed by the movable mold a and the fixed mold j. The flow rate of the pressure oil guided to the tightening-side oil chamber k is different, and when a certain one of the four pipes r, x, y, and z, for example, the pipe r becomes difficult to flow, another flow easily occurs. For example, since the fluid flows into the pipe x, the balance is lost and the parallelism of the die plates b and d cannot be maintained.

[0005] In particular, a shear structure in which a molten resin is supplied into the mold in a state where a mold requiring parallelism for opening and closing the mold is appropriately opened, and the molten resin is spread to a predetermined shape by a supply pressure and a pressing pressure. When mounting the mold, the mold is closed first, then the origin is determined with the pressure increased, and the parallelism of the die plate is derived from this origin, so if this origin is not accurately derived, the mold will be damaged The problem arises.

As a solution to such a problem, a closed loop control using a servo valve is known. This system detects the position of each mold clamping cylinder and controls the amount of pressure oil flowing into each cylinder. This results in a very expensive device.

[0007] There is also a method in which a pressurized oil is applied to a plurality of mold clamping cylinders using a synchronous shunt valve to obtain a parallelism between the two die plates. Since the pressure oil is diverted by changing the pressure, there is a disadvantage that the diverting is not performed accurately.

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a mold clamping apparatus for an injection molding machine which is capable of accurately maintaining the parallelism of a die plate while being inexpensive. An apparatus and a mold clamping method are provided.

[0009]

According to the present invention, there is provided a mold clamping device for solving the above-mentioned problems, which comprises: abutting a fixed mold fixed to a fixed die plate with a movable mold attached to a movable die plate; By supplying pressurized oil to the clamping-side oil chamber of a plurality of clamping cylinders provided on the fixed die plate,
In a mold clamping device of an injection molding machine, the moving die plate was strongly clamped to a fixed die plate side to perform mold clamping.
A plurality of mold clamping cylinders, a hydraulic source of pressure oil supplied to each of the mold clamping cylinders, and a plurality of hydraulic motors connected in parallel downstream of the hydraulic source; and A flow divider for performing synchronous splitting to hydraulic pipes connected to the respective outlets, and connecting the plurality of hydraulic pipes for which synchronous splitting is performed by the flow divider to a mold-side oil chamber of each of the mold-clamping cylinders. It is configured to include a plurality of connection hydraulic pipes.

After the fixed mold fixed to the fixed die plate and the movable mold attached to the movable die plate come into contact with each other,
By supplying pressurized oil to the mold clamping side oil chambers of a plurality of mold clamping cylinders provided at the four corners of the fixed die plate, the movable die plate is strongly pressed to the fixed die plate side to perform mold clamping. In the mold clamping device of the injection molding machine described above, the plurality of mold clamping cylinders, a hydraulic source of pressure oil supplied to each of the mold clamping cylinders are connected in parallel downstream of the hydraulic source and synchronized. First and second flow dividers that are provided with a plurality of hydraulic motors and that perform synchronous splitting to hydraulic pipes connected to respective outlets of the hydraulic motors, and two flow splitters that perform synchronous splitting by these flow dividers. A plurality of connection hydraulic pipes for connecting hydraulic pressure pipes to the clamping-side oil chambers of two clamping cylinders on diagonal lines of a plurality of clamping cylinders provided at four corners of the fixed die plate, respectively. Configuration One in which the.

In order to solve the above-mentioned problem, as a method of clamping the mold, a plurality of fixed mold plates provided on the fixed die plate are brought into contact after a fixed mold fixed to the fixed die plate and a movable mold attached to the movable die plate are brought into contact with each other. A mold clamping method for an injection molding machine in which pressurized oil is supplied to a mold clamping side oil chamber of a mold clamping cylinder to strongly mold the movable die plate toward the fixed die plate to perform mold clamping. A flow divider having a plurality of hydraulic motors connected in parallel downstream of the hydraulic power source performs synchronous shunting to hydraulic pipes connected to the respective outlets, and transfers the synchronized shunted pressure oil to the mold clamping side of the mold clamping cylinder. By guiding the movable die plate to the fixed die plate side by guiding the movable die plate to the oil chamber, mold clamping is performed.

[0012]

According to the mold clamping apparatus and the mold clamping method of the present invention, a synchronous divider to a hydraulic pipe connected to each outlet is provided by a flow divider having a plurality of hydraulic motors connected in parallel downstream of a hydraulic source. By conducting the synchronously divided pressure oil to the mold clamping side oil chamber of the mold clamping cylinder, the moving die plate is strongly pressed to the fixed die plate side to perform mold clamping. The amount of pressure oil acting on each mold-side oil chamber of the mold-clamping cylinder is always constant. As a result, it is possible to accurately maintain the parallelism of the die plate while maintaining a low cost.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. 2 and 3 show a schematic configuration of the mold clamping device of the present invention. FIG. 2 shows a mold opened state, and FIG. 3 shows a mold clamped state. In the figure, 1 is a fixed die plate, and 2 is a movable die plate. A fixed die 3 is attached to the fixed die plate 1, and a movable die 4 is attached to the movable die plate 2.

A plurality of mold opening / closing cylinders 10 (only one is shown) each having one end of a plunger 10a connected to the movable die plate 2 are mounted on the fixed die plate 1, and the movable mold 4 is mounted thereon. Moving die plate 2
The fixed die plate 1 with the fixed mold 3 attached thereto.
In the direction in which it comes into contact with and separates from the camera (left and right directions in the figure). The dies 3 and 4 are separated from each other as shown in FIG. 2 or are brought into contact with each other as shown in FIG.

At four corners of the fixed die plate 1, first to fourth clamping cylinders 12, 13, 14, 15 are attached. These mold clamping cylinders 12, 13,
The four tie bars 16,... Formed by the plungers 14 and 15 are provided in the through holes 1 provided in the movable die plate 2.
7 are penetrated, and their distal ends are fixed to the connecting plate 18.

The tie bars 16,... Are composed of a large diameter portion 16a and a small diameter portion 16b, and have a step 16c at the boundary between these. Then, the step 16c of the large diameter portion 16a
The screw portions 19 are formed in the vicinity of.

A stopper 20 provided on the opposite die mounting surface of the movable die plate 2 is externally fitted to the small diameter portion 16b, and a half nut adjacent to the stopper 20 and capable of meshing with the screw portion 19 is provided. 21 are provided.

In the drawing, reference numeral 25 denotes an injection device provided with an injection nozzle for injecting a resin from a resin supply device (not shown) into a cavity (not shown) formed by the molds 3 and 4.

Also, as shown in FIG.
Pressure oil acts on the mold clamping cylinders 12, 13, 14, and 15 by the hydraulic supply circuit device 30, respectively.

The hydraulic supply circuit device 30 includes a hydraulic source 31,
Four hydraulic motors 33, 34, 35, 36 connected in parallel via a pipe 32 downstream of the hydraulic source 31 are provided.
And a hydraulic pipe 33 connected to each outlet of the hydraulic motor.
a, 34a, 35a, and 36a, and a hydraulic divider 33a, 34a, 35a, and 3 for performing synchronous division by the flow divider.
6a and four connecting hydraulic pipes 41, 42, 43, 44 for connecting the mold clamping cylinders 12, 13, 14, 15 to the mold clamping side oil chambers 12a, 13a, 14a, 15a. The configuration is Next, a mold clamping operation of the mold clamping device configured as described above will be described. First,
In the mold open state shown in FIG. 2, the mold opening / closing cylinders 10 are operated to move the movable die plate 2 to which the movable mold 4 is attached in the right direction in the figure.

As shown in FIG. 3, when the movable mold 4 comes into contact with the fixed mold 3, the stopper 20
Step 16 at the boundary between the large-diameter portion 16a and the small-diameter portion 16b
c, and the thread portion 19 formed on the tie bar 16,.
The half nuts 21 mesh with each other, so that the fixed mold 3 and the movable mold 4 are firmly connected.

Thereafter, the hydraulic supply circuit shown in FIG. 1 is supplied to the respective clamping-side oil chambers 12a, 13a, 14a, 15a of the clamping cylinders 12, 13, 14, 15 provided at the four corners of the fixed die plate 1. The tie bars 16,... Are pulled rightward in the figure by applying pressure oil through the device 30 to perform mold clamping.

At this time, the mold clamping cylinders 12, 13, 1
4, 15 respectively, the mold-side oil chambers 12a, 13a, 14a,
15a is connected to a hydraulic connecting pipe 4 via a flow divider 37 provided with hydraulic motors 33, 34, 35, 36 in parallel.
Pressure oil is guided through 1, 42, 43 and 44.

With such a configuration, the hydraulic motors 33, 34, 35, and 36 rotate the motor at a high speed, unlike the conventional flow dividing valve which performs the flow dividing by changing the gap through which the pressure oil passes. The pressure is discharged as a volume of pressurized oil, so that a more accurate split flow can be performed. Thereby, the parallelism between the fixed die plate 1 and the movable die plate 2 can be accurately maintained.

FIG. 4 shows a modification of the first embodiment, in which all of the four hydraulic motors 33, 34, 35, 36 are connected by a drive shaft 50 so as to be driven synchronously. It is like that. According to this, the mold clamping cylinders 12, 13,
The pressure oil synchronized with 14 and 15 acts to maintain the parallelism of the movable die plate 2.

FIG. 5 shows a second embodiment of the present invention, which synchronizes with a first flow divider 37A in which first and second hydraulic motors 33 and 34 are provided in parallel. The third and fourth hydraulic motors 35 and 36 are divided into a second flow divider 37B provided in parallel.

The connecting hydraulic pipes 40 and 41 connecting to the hydraulic pipes 33a and 34a of the hydraulic motors 33 and 34 of the first flow divider 37A are fixed to the fixed die plate 3.
In FIG. 0, the first mold clamping cylinder 12 at the upper left corner and the lower right corner on the diagonal line and the mold clamping side oil chambers 12a and 14a of the third mold clamping cylinder 14 are connected, and the second flow divider 37B Hydraulic piping 35a, 36 for hydraulic motors 35, 36
The connecting hydraulic pipes 42 and 43 connecting to the second die clamping cylinder 13 and the fourth die clamping cylinder 15 at diagonally lower left and upper right corners in the figure of the fixed die plate 30 are connected to each other.
To the mold clamping side oil chambers 13a and 15a.

As described above, the flow dividers 37A, 3A
Pressurized oil from 7B is supplied to the diagonal mold clamping cylinders 12 and 14,
By assigning them to and 13 and 15, respectively, it becomes easier to maintain the parallelism.

As described above, according to the present invention, a plurality of hydraulic motors 33,
Flow divider 37 (37) provided with 34, 35, 36
A, 37B) hydraulic piping 33 connected to each outlet
a, 34a, 35a, and 36a, and divides the synchronized hydraulic oil into the mold clamping cylinders 12, 13, 1
4, 15 mold closing side oil chambers 12a, 13a, 14a, 15a
The movable die plate 2 is strongly pressed toward the fixed die plate 1 to perform the mold clamping, so that the mold divider cylinder 1 is moved from the flow divider 37 (37A, 37B).
The mold-side oil chambers 12a, 13 of 2, 13, 14, 15 respectively
The amount of pressurized oil acting on a, 14a and 15a is always constant. Thereby, it is possible to accurately maintain the parallelism between the fixed die plate 1 and the movable die plate 2 while having a low cost. In the description of the above-described embodiment, the same parts as those of the above-described embodiment are denoted by the same reference numerals, and the description thereof will not be repeated. It is needless to say that the present invention can be variously modified without departing from the scope of the present invention.

[0030]

As described above, according to the mold clamping apparatus and the mold clamping method of the present invention, each mold outlet is connected to each outlet by a flow divider provided with a plurality of hydraulic motors connected in parallel downstream of a hydraulic source. By performing synchronous shunting to the hydraulic piping to be performed, and guiding the synchronized shunted pressure oil to a mold-clamping-side oil chamber of the mold-clamping cylinder, the movable die plate is strongly pressed to the fixed die plate side to perform mold clamping. Therefore, the amount of pressure oil acting from the flow divider to each of the mold-clamping-side oil chambers of the mold-clamping cylinder is always constant. Thus, there is an effect that the parallelism of the die plate can be accurately maintained while the cost is low.

[Brief description of the drawings]

FIG. 1 is a diagram showing a hydraulic supply circuit device in a first embodiment of a mold clamping device according to the present invention.

FIG. 2 is a schematic configuration diagram showing a mold opening state of the mold clamping device of the present invention.

FIG. 3 is a schematic configuration diagram showing a mold clamping state.

FIG. 4 is a diagram showing a modification of the hydraulic pressure supply circuit device according to the first embodiment.

FIG. 5 is a diagram showing a hydraulic circuit in a second embodiment of the mold clamping device of the present invention.

FIG. 6 is a schematic configuration diagram showing a mold clamping state of a conventional mold clamping device.

FIG. 7 is a diagram showing a hydraulic supply circuit device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fixed die plate, 2 ... Moving die plate, 3 ... Fixed mold, 4 ... Moving mold, 10a ... Plunger, 10 ... Mold opening / closing cylinder, 12, 13, 14, 15 ... Mold clamping cylinder, 12a, 13a, 14a, 15a: mold-side oil chamber, 1
6 ... Tie bar, 19 ... Screw, 20 ... Stopper, 21 ...
Half nut, 30 hydraulic pressure supply circuit device, 31 hydraulic pressure source, 32 piping, 33, 34, 35, 36 hydraulic motor, 33a, 34a, 35a, 36a hydraulic piping, 3
7, 37A, 37B ... flow dividers, 41, 42,
43, 44: Connection hydraulic piping, 50: Drive shaft.

Claims (3)

(57) [Claims] 1. A mold-clamping-side oil chamber of a plurality of mold-clamping cylinders provided on the fixed die plate after abutment of a fixed mold fixed to the fixed die plate with a movable mold attached to the movable die plate. In the mold clamping device of an injection molding machine in which the movable die plate is strongly pressed to the fixed die plate side to perform mold clamping by supplying pressure oil to the plurality of mold clamping cylinders, A hydraulic source of pressure oil supplied to the mold clamping cylinder, and a plurality of hydraulic motors connected in parallel downstream of the hydraulic source, and synchronized with a hydraulic pipe connected to each outlet of the hydraulic motor. A flow divider that performs flow splitting, and a plurality of connection hydraulic pipes that connect the plurality of hydraulic pipes and the clamping-side oil chamber of each of the mold-clamping cylinders in which the divided flow is synchronously performed by the flow divider. Features that become Mold clamping apparatus of an injection molding machine for. 2. A mold clamping side of a plurality of mold clamping cylinders provided at four corners of the fixed die plate after contact between a fixed mold fixed to the fixed die plate and a movable mold attached to the movable die plate. By supplying pressurized oil to the oil chamber, in a mold clamping device of an injection molding machine in which the movable die plate is strongly pressed to the fixed die plate side to perform mold clamping, the plurality of mold clamping cylinders, A hydraulic source of hydraulic oil supplied to each of the mold clamping cylinders, and two hydraulic motors connected in parallel and synchronized downstream of the hydraulic source, and hydraulic pressures connected to respective outlets of the hydraulic motors First and second flow dividers for performing synchronous splitting to the pipes, and each of the two flow splitters for performing synchronous splitting by these flow dividers
A plurality of connecting hydraulic pipes respectively connecting the two hydraulic cylinders on the diagonal line of a plurality of the closing cylinders provided at the four corners of the fixed die plate with hydraulic pressure pipes; And a mold clamping device for an injection molding machine. 3. A mold clamping side oil chamber of a plurality of mold clamping cylinders provided on the fixed die plate after the fixed mold fixed to the fixed die plate and the movable mold attached to the movable die plate come into contact with each other. A method of clamping an injection molding machine in which the movable die plate is strongly pressed to a fixed die plate side to supply a pressurized oil to the fixed die plate side, and is connected in parallel downstream of a hydraulic pressure source. A flow divider provided with a plurality of hydraulic motors performs synchronous shunting to a hydraulic pipe connected to each outlet, and guides the synchronized shunted pressure oil to a mold-clamping-side oil chamber of the mold-clamping cylinder. A mold clamping method for an injection molding machine, wherein the mold is clamped by forcibly pressing the mold against a fixed die plate.