JPH02214638A - Clamping device for injection molding machine - Google Patents

Abstract

PURPOSE:To make the driving energy small at the time of mold opening and closing, and simplify and make electric wiring and hydraulic piping small by mounting a small mold-opening and closing cylinder having large stroke and a clamping cylinder of medium size having a small stroke. CONSTITUTION:A clamping device is provided with a piston rod 24 connected with a movable platen 34, a small mold-opening and closing cylinder 32 having large stroke and the piston rod connected with the bars 4 and a medium size diameter clamping cylinder 35 having small stroke with its cylinder section connected with a base plate 31 are provided. Also as an adjusting unit 38 supported rotatably on the base plate 31 and a mold thickness adjusting shaft 39 moving forward and backward to an end face of a rod 46 corresponding to the rotation of said adjusting nut are mounted and also a shutter 49 is disposed movable forward and backward between an end surface of the rod adjusting shaft, when pressure oil is fed into the clamping cylinder 35 at the time of clamping, clamping force is transferred to the movable platen 5 through the base plate, the adjusting nut, the mold thickness adjusting shaft, a shutter and the rod.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a mold clamping device for an injection molding machine.

(Prior art) Conventionally, a molding material that has been heated and fluidized in a heating cylinder is injected into a mold under high pressure, cooled and solidified or hardened therein, and then the mold is opened to take out the molded product. As a mold clamping device for such an injection molding machine, a booster type device as shown in FIG. 4 is provided.

In the figure, a base plate 2 and a fixed platen 3 are erected on a frame 1, and a tie bar 4 is disposed between them. The tie bars 4 slidably support a movable platen 5, and the movable platen 5 moves toward and away from the fixed platen 3.

A fixed mold 6 is mounted on the fixed platen 3, and a movable platen 5 is mounted on the fixed mold 6.
A movable mold 7 is disposed in the mold 7, and molding material is filled between the two molds 6 and 7 during the injection process.

The molds 6 and 7 are placed in contact when filling with molding material, but must be opened when taking out the molded product. For this reason, the movable platen 5 is equipped with a mold clamping device 8.
is provided.

That is, a main cylinder 9 is formed behind the base plate 2, and a piston 10 is disposed to slide inside the main cylinder 9.

A main cylinder chamber 11 formed between the end surface of the piston 10 and the main cylinder 9 accommodates hydraulic oil for reciprocating the piston IO. Therefore, the main cylinder chamber 11 is connected to a prefill pipe 13 via a prefill valve 12.

Further, a booster cylinder 14 is formed in the center of the piston lO in the axial direction, and the booster cylinder 14 is formed in the center of the piston lO.
A tubular booster 15 is disposed within 4 so as to be movable forward and backward. The booster 15 is connected to a pipe that extends rearward and supplies high-pressure hydraulic oil.

In the mold clamping device of the injection molding machine configured as described above, the main cylinder 9 is operated during high-speed mold closing or mold opening, and a large amount of oil is supplied or discharged. On the other hand, during high-pressure mold clamping or mold opening, the booster cylinder 14 is operated to supply and discharge high-pressure oil.

However, in the mold clamping device of the above-mentioned injection molding machine, a main cylinder 9 with a large diameter and a large stroke is used, so the amount of hydraulic oil required for opening and closing the mold is extremely large, and the dimensions of the prefilled pulp 12 are reduced. , it is necessary to increase the dimensions of the prefill piping 13, the tank capacity, etc., and energy efficiency deteriorates.

Furthermore, when generating the mold clamping force, the volume of the portion where the hydraulic pressure is raised to a predetermined pressure is large, and the time required to do so becomes long.

Furthermore, since the piston 10 moves integrally with the movable platen 5, its inertia increases, resulting in poor controllability during acceleration and deceleration.

Therefore, in order to solve the above problems, a cylinder type mold clamping device is provided which has a mold opening/closing cylinder with a small diameter and a large stroke and a mold clamping cylinder with a large diameter and a small stroke.

FIG. 5 shows the conventional cylinder type mold clamping device.

In the figure, a mold opening/closing cylinder 21 with a small diameter and a large stroke is shown.
is arranged behind the movable platen 5, and the piston 22 of the nuclear mold opening/closing cylinder 21 is connected to the movable platen 5 via a rod 23. When pressure oil is supplied to the cap side of the mold opening/closing cylinder 21, the piston 22 moves the movable platen 5 to the right to close the mold, and by supplying pressure oil to the rond side, the movable platen 5 is moved to the left. The mold is opened by moving it to

The movable platen 5 moves along a tie bar 4 extending between the fixed platen 3 and the base plate 2.

Then, after the mold is closed and the molds 6°7 come into contact, mold clamping is performed.

For the mold clamping described above, a mold clamping cylinder 24 with a large diameter and a small stroke is disposed on the back surface of the base plate 2. When pressure oil is supplied to the mold clamping cylinder 24, the piston 25 moves to the right.

The piston 25 is hollow with a through hole 26 formed in the center, and when the mold is opened, a threaded rod 27 for adjusting mold thickness is inserted into the piston 25.
can be accommodated.

The mold thickness adjusting screw 27 can be engaged with a nut 28 fixed to the back surface of the movable platen 5. Then, it is possible to change the relative position of only the stroke S between the nut 28 and the mold thickness adjusting threaded rod 27 in accordance with the thickness of the mold 6.7. The adjusting screw rod 27 is rotated manually, by an electric motor, an oil motor, or the like.

By the way, a shutter 29 is provided between the front end surface of the piston 25 sliding on the mold clamping cylinder 24 and the rear end surface of the mold thickness adjusting screw 27, and is moved forward and backward by a shunter cylinder (not shown). The shutter 29 is connected to the front end surface of the piston 25 and the mold thickness adjustment threaded rod 27.
When the mold clamping cylinder 24 is pressurized while being interposed between the rear end faces, the mold clamping force is applied to the movable mold via the piston 25, the mold thickness adjustment threaded rod 27, the nut 28, and the movable platen 5. 7.

(Problem to be solved by the invention! I) However, in the mold clamping device of the conventional injection molding machine, the mold thickness adjustment threaded rod 27 and the nut 28 for adjusting the mold thickness are Since it is disposed between the shutter 29 and the movable platen 5, the mold clamping device becomes longer by the adjustment stroke S. Furthermore, the mold thickness adjusting threaded rod 27 and the nut 28 move integrally with the movable platen 5 (therefore, weight increases, energy efficiency deteriorates, and controllability during acceleration and deceleration may deteriorate). Also, the electrical wiring or hydraulic piping becomes complicated.

The present invention solves the above-mentioned problems and provides a mold clamping device for an injection molding machine that reduces driving energy when opening and closing the mold, is compact, and simplifies electrical wiring and hydraulic piping. The purpose is to provide.

(Means for Solving the Problems) For this purpose, the present invention provides a fixed platen that supports a fixed mold, and a movable mold that supports a movable mold opposite to the fixed platen and moves along tie bars to move both molds. In a mold clamping device for an injection molding machine that has a movable platen that moves the movable platen toward and away from the movable platen, a rod that is disposed on the back of the movable platen and moves together with the movable platen, and a piston rod are connected to the movable platen. It has an opening/closing cylinder, and a medium-diameter, small-stroke clamping cylinder whose piston rod is connected to a tie bar and whose cylinder part is connected to a base plate.

An adjustment nut rotatably supported by the base plate and a mold thickness adjustment shaft that moves forward and backward relative to the end surface of the rod as the adjustment nut rotates are provided.

Further, a shutter is provided between the end face of the rod and the end face of the mold thickness adjustment shaft so as to be able to move forward and backward, so that it moves forward when the mold is clamped and retreats when the mold is opened and closed.

(Function) According to the present invention, the rod that is disposed on the back surface of the movable platen and moves together with the movable platen, and the piston rod are connected to the movable platen or its connecting parts, and the mold opening/closing cylinder with a small diameter and a large stroke and the piston It has a medium-diameter, small-stroke mold clamping cylinder whose rod is connected to a tie bar and whose cylinder part is connected to a base plate, and an adjustment nut rotatably supported by the base plate, and a mold clamping cylinder whose cylinder part is connected to a base plate. Accordingly, a mold thickness adjustment shaft is provided that moves forward and backward with respect to the end surface of the rod, and a shutter is provided between the end surface of the rod and the end surface of the mold thickness adjustment shaft so that it can move forward and backward. When pressure oil is supplied to the mold clamping cylinder during mold clamping, the mold clamping force is transmitted to the movable platen via the base plate, adjustment nand, mold thickness adjustment shaft, shutter, and rod.

When adjusting the mold thickness, when the electric motor or oil motor is driven to rotate the adjusting nut, the mold thickness adjusting shaft moves in the rod direction, and the position of the movable platen can be changed.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a state diagram when the mold is closed in the mold clamping device of the injection molding machine of the present invention, FIG. 2 is a state diagram when the mold is clamped, and FIG. 3 is a state diagram when the mold is opened.

In the figure, a fixed platen 3 is vertically fixed to a frame 1, a base plate 31 is placed upright to face it, and a tie bar 4 is disposed between the two. The tie bars 4 slidably support a movable platen 5, and the movable platen 5 moves toward and away from the fixed platen 3.

A fixed mold 6 is disposed on the fixed platen 3, and a movable mold 7 is disposed on the movable platen 5, so that molding material is filled between the two molds 6 and 7 during the injection process. ing. The molds 6.7 are placed in contact when filling with molding material, but must be opened when taking out the molded product. For this reason, small diameter and large molds are placed on the back of the movable platen 5. A stroke mold opening/closing cylinder 32 is provided, and a piston rod 34 connected to a piston 33 sliding therein is connected to the back side of the movable platen 5. Therefore, the movable platen 5 is moved to the right or left by supplying pressure oil to both sides of the piston 33 in the mold opening/closing cylinder 32.

Further, a mold clamping cylinder 35 with a medium diameter and a small stroke is disposed at the rear end of each tie bar 4, and its piston 3
6 is fixed to the end of the tie bar 4.

The cylinder portion 37 of the mold clamping cylinder 35 is fixed to the base plate 31. A port (a) is formed on the rear end surface of the cylinder portion 37, and a port (b) is formed on the side wall.

By the way, the thickness of the mold 6.7 varies depending on the shape and dimensions of the molded product. Therefore, a mold thickness adjustment mechanism is provided so that it can correspond to each stack thickness. The mold thickness adjustment mechanism includes an adjustment nut 38 rotatably supported by the base plate 31;
It is composed of a mold thickness adjustment shaft 39 that engages with the mold thickness adjustment shaft 39 and moves back and forth. The adjustment nut 38 is connected to a drive means 41 such as an electric motor or a hydraulic motor via a gear, a chain, a timing belt, or the like. A through hole 45 is formed in the center of the mold thickness adjustment shaft 39, and a rod 46 is provided on the back surface of the movable platen 5, and when the mold is opened, the rod 46 is inserted into the through hole. It is designed to be housed within 45.

A shutter 49 is provided between the front end surface 47 of the mold thickness adjusting shaft 39 and the rear end surface 48 of the rod so as to be able to move forward and backward. The shutter 49 is driven by a shutter cylinder 5G, and is moved backward when the mold is closed and opened, as shown in FIGS. 1 and 3, and advanced when the mold is clamped, as shown in the second time.

Note that the adjustment of the mold thickness is performed when the molds 6 and 7 are attached. If the gap between the rod 46 and the shutter 49 is set to be extremely small (within a few square meters) during the S mold clamping, the stroke of the mold clamping cylinder 35 during mold clamping can be made small.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As explained above, according to the present invention, the rod that is disposed on the back surface of the movable platen and moves together with the movable platen, and the piston rod are connected to the movable platen or its connecting parts, and the rod is small in diameter and large in diameter. It has a mold opening/closing cylinder with a stroke, a mold clamping cylinder with a medium diameter and a small stroke, whose piston rod is connected to a tie bar, and whose cylinder part is connected to a base plate, and an adjustment nut rotatably supported on the base plate. A mold thickness adjustment shaft is provided that moves forward and backward relative to the end surface of the rod as the adjustment nut rotates, and a shutter moves forward and backward between the end surface of the rod and the end surface of the mold thickness adjustment shaft. Because they are freely arranged, when pressure oil is supplied to the mold clamping cylinder during mold clamping, the mold clamping force is transmitted to the movable platen via the base plate, adjustment nand, mold thickness adjustment shaft, shack, and rod. be done.

Therefore, the mold clamping cylinders are arranged separately at the ends of each tie bar, the weight of each winter clamping cylinder is reduced, and the work space is widened, making assembly, maintenance, and management easier.

In addition, a mold clamping cylinder is installed at the end of each tie bar, so even if a mold with poor parallelism is used, the force generated on the tie bar can be made uniform, and a specific tie bar may be overloaded. This will prevent it from breaking due to stress.

Furthermore, since the mold thickness adjustment mechanism is located at the rear of the shack 49, the size of the mold clamping device is reduced by the adjustment stroke S, which not only makes it possible to make it smaller and lighter (but also to reduce costs). , the mold thickness adjustment mechanism is
Since it is disposed separately from the movable platen 5, the weight of the movable part during opening and closing of the mold is reduced, operating energy can be reduced, and controllability during acceleration and deceleration is improved. Also,
Electrical wiring and hydraulic piping can also be simplified.

[Brief explanation of the drawing]

Fig. 1 is a state diagram when the mold is closed in the mold clamping device of the injection molding machine of the present invention, Fig. 2 is a state diagram when the mold is clamped, Fig. 3 is a state diagram when the mold is opened, and Fig. 4 is a state diagram of the conventional injection molding machine. FIG. 5 is a diagram showing a booster type mold clamping device, and FIG. 5 is a diagram showing a conventional cylinder type mold clamping device. DESCRIPTION OF SYMBOLS 1... Frame, 3... Fixed platen, 4... Tie bar, 5... Movable platen, 6... Fixed mold, 7...
...Movable mold, 31...Base plate, 32...
Mold opening/closing cylinder, 33... Piston, 34... Piston rod, 35... Mold clamping cylinder, 36... Piston, 37... Cylinder part, 38... Adjusting nut,
39...Mold thickness adjustment shaft, 45...Through hole, 46...
...Rot Y, 49...Shutter, 50...Shutter cylinder. Patent applicant: Sumitomo Heavy Industries, Ltd. Sub-agent Patent attorney: Makoto Kawagoi (1 other person) Figure 1 Figure 2

Claims (1)

[Scope of Claims] A fixed platen that supports a fixed mold, and a movable platen that supports a movable mold so as to face the fixed platen and moves along tie bars to move the molds toward and away from each other. In the mold clamping device of an injection molding machine, (a) a rod is arranged on the back side of the movable platen and moves together with the movable platen, and (b) a piston rod is connected to the movable platen or its connecting parts, and has a small diameter and a large stroke. a mold opening/closing cylinder; (c) a medium-diameter, small-stroke mold clamping cylinder whose piston rod is connected to a tie bar and whose cylinder portion is connected to a base plate; (d) an adjustment nut rotatably supported by the base plate; (e) a mold thickness adjustment shaft that moves forward and backward with respect to the end surface of the rod as the adjustment nut rotates; and (f) a mold thickness adjustment shaft that can freely move back and forth between the end surface of the rod and the end surface of the mold thickness adjustment shaft. 1. A mold clamping device for an injection molding machine, comprising a shutter that is disposed in the mold, moves forward when the mold is clamped, and retreats when the mold is opened and closed.