JPH0259022B2 - - Google Patents

Description

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

(Prior Art) FIG. 7 shows a mold clamping device of a typical conventional vertical injection molding machine.

Reference numeral 1 denotes a stationary plate fixed to a base 20, on which a stationary mold 1a is fixed. 2 is an upper movable platen, on which a movable mold 2a is fixed. Reference numeral 13 denotes a lower movable plate with an oil passage 13a in the center, and four tie bars 14, 14, 14', 14' that can move up and down guided by a through hole provided in the fixed plate 1, It is connected to the movable platen 2. Reference numeral 15 denotes a mold clamping cylinder, the upper end of which is fixed to the lower surface of the fixed platen 1 together with a booster ram 16 protruding from the center, and a cylinder cover 15a having a through hole 15a' is fixed to the lower end. 17 is a piston paired with the mold clamping cylinder 15, and the piston head 17a is provided with a through hole 17a' into which the booster ram 16 is slidably fitted;
The cylindrical skirt portion 17b has its lower end fixed to the upper surface of the lower movable platen 13, and can slide in the through hole 15a' of the cylinder cover in an oil-tight manner.

As described above, the oil chamber A is provided in the skirt portion 17b, the outer peripheral surface of the skirt portion 17b and the mold clamping cylinder 1 are
An oil chamber B is formed between the upper surface of the piston head 17a and the inner peripheral surface of the mold clamping cylinder 15, and an oil chamber C is formed between the upper surface of the piston head 17a and the upper inner peripheral surface of the mold clamping cylinder 15. The oil chamber B and the oil chamber C are each provided with a pressure oil supply/discharge port (not shown).

Pressure oil is introduced into the oil chamber A and the upper movable platen 2 is lowered to align the fixed mold 1a and the movable mold 2a, and further pressure oil is introduced into the oil chamber C to clamp the molds. Next, when the pressure oil in both oil chambers A and C is discharged and pressure oil is introduced into oil chamber B, the upper movable platen 2 is raised and the movable mold 2a and the fixed mold 1a are opened. .

(Problems to be Solved by the Invention) The mold clamping device of a conventional vertical injection molding machine had the above-mentioned configuration, and therefore had the following problems.

(a) The fixed mold 1a was installed at a high position, making the work difficult.

Let the mold opening/closing stroke length be S, and mold clamping cylinder 1
5 bottom thickness t ₁ , piston head 17a thickness
t ₂ and the thickness of the cylinder cover 15a is t ₃ , the length of the clamping cylinder 15 is t ₁ + t ₂ + t ₃ + S + △S,
This value is approximately 2S, and the gap between the stroke length of the lower movable platen 13 and the base plane L, and the gap between the lower movable platen 1
3, the thickness of the fixed platen 1, etc., the height from the base plane L to the fixed mold 1a becomes considerably high, and a step stool is installed to remove burrs after taking out the product and to remove the burrs from the fixed mold 1a. It is necessary to assemble parts, which makes the work difficult, and therefore there is a problem in incorporating such a vertical injection molding machine into the automation process.

(b) The mold opening/closing speed was slow.

Since the outer circumferential surface of the piston 17 and the inner circumferential surface of the mold clamping cylinder 15 slide while maintaining oil tightness, the sliding resistance is large, and therefore the mold opening/closing speed is slow.

(c) The upper and lower movable plates 2 and 13 fell under their own weight, damaging both molds 1a and 2a.

If the mold is left open for a long time, the upper and lower movable plates 2, 13 may leak due to a slight oil leak between the outer circumferential surface of the piston 17 and the inner circumferential surface of the mold clamping cylinder 15.
The metal molds 1a and 2a collided with each other and were damaged.

(d) It required a large flow of hydraulic oil.

In the mold opening process, it is necessary to send hydraulic oil to oil chamber A and to oil chamber C via a pre-fill valve, etc., but high pressure hydraulic oil is sent to oil chamber C in the mold clamping process. In order to generate a predetermined mold clamping force, the area of the piston head 17a is large, and therefore, a large flow of hydraulic oil is supplied to and discharged from the mold clamping cylinder 15 during the mold opening and closing process.

(Means for Solving the Problems) The present invention has been made to solve the above-mentioned problems of the mold clamping device of a conventional vertical injection molding machine, and the gist of the first invention is In a mold clamping device for a vertical injection molding machine in which an upper movable plate to which a movable mold is fixed is moved up and down with a tie bar to a fixed plate, a rack or pinion is fixed to the lower surface of the fixed plate, and the rack or pinion is fixed to the lower surface of the fixed plate. A pinion that meshes with the pinion or a rack that meshes with the pinion is fixed to the tie bar side, a reversible motor with a brake is provided to drive the pinion, and the motor is rotated in the forward or reverse direction to move the upper movable plate up and down with respect to the fixed plate. This is a mold clamping device for a vertical injection molding machine.

The gist of the second invention is a mold clamping device for a vertical injection molding machine in which an upper movable plate to which a movable mold is fixed is moved up and down with a tie bar with respect to a fixed plate to which a fixed mold is fixed. A rack or pinion is fixed to the lower side, a pinion that meshes with the rack or a rack that meshes with the pinion is fixed to the tie bar side, a reversible motor with a brake is provided to drive the pinion, and a piston is fitted to the upper movable platen. A movable mold is fixed to the lower surface of the piston, and the motor is rotated forward or backward to move the upper movable plate up and down with respect to the fixed plate, and pressure oil is introduced into the cylinder. This is a mold clamping device for a vertical injection molding machine that completes mold clamping.

In each of the above inventions, the difficulty of the fixed plate is as follows:
The rack has teeth on both sides, and the rack provided on the tie bar side may be a normal rack with teeth on one side.

(Function) In the first invention, since the rack or pinion provided on the lower surface of the fixed plate meshes with the pinion or rack provided on the tie bar side connected to the upper movable plate, the reversible motor with brake Or conversely, by rotating the pinion, the movable tie bar moves and moves the upper movable plate up and down with respect to the fixed plate, thereby aligning the movable mold with the fixed mold, clamping the mold, and The mold is opened.

In addition, in the second invention, in the same manner as in the first invention, the molds are matched, the molds are clamped, and the molds are opened. Apply clamping force to complete mold clamping.

(Example) A first example of a mold clamping device for a vertical injection molding machine according to the present invention will be described based on FIGS. 1 to 3.

Reference numeral 1 designates a fixed plate which is fixed to a base 20 with a fixed mold 1a fixed thereon, and 2 is an upper movable plate which has a movable mold 2a fixed thereon. 4 and 4' are tie bars, which are guided through holes provided at the four corners of the fixed platen 1 and are connected to the upper movable platen 2.
and the lower movable platen 3 can be connected to move up and down. A square hole 3a is provided in the lower movable platen 3, and a rack 5, which is fixed to the lower surface of the fixed platen 1 and has teeth on both sides and is slightly longer than the mold opening/closing stroke length S, is suspended in the square hole 3a. I've let it happen. Reversible motors 7, 7 with brakes driven by hydraulic pressure or electricity are fixed to the lower movable platen 3, and pinions 6, 6 fixed to the shafts of both motors 7, 7 are connected to the teeth on both sides of the rack 5. It is engaged with the part.

Next, the effect will be explained.

In FIG. 1, when the reversible motors 7, 7 are rotated forward in the direction of the arrow, the lower movable platen 3 is lowered together with the upper movable platen 2 by the action of the pinions 6, 6 meshing with the rack 5, and both The molds 1a and 2a are matched and then clamped (see FIG. 2). After the mold clamping is completed, the driving source of both reversible motors 7, 7 is cut off and the brakes are applied by operating a limit switch (not shown) or the like.

After the injection molding machine is finished, as shown in FIG. 2, if the reversible motors 7, 7 are reversely rotated in the direction of the arrow, the lower movable platen 3 is moved upward by the action on the pinions 6, 6 that mesh with the rack 5. It rises together with the movable platen 2, and both molds 1a and 2a are opened. After the mold has been opened sufficiently, the driving sources of the two reversible motors 7, 7 are cut off and the motors are braked by operating a limit switch (not shown) or the like.

A second embodiment will be described based on FIGS. 4 and 5. The same reference numerals as in the first embodiment indicate the same parts, and the explanation will be omitted.

Reference numeral 8 denotes a connecting plate that connects two adjacent tie bars 4, 4' of the four tie bars on the lower side of the fixed platen 1, and a mold opening/closing stroke length S is provided approximately at the center of each connecting plate 8, 8. Slightly longer rack 5',
5' is installed vertically. Reversible motor 7 with brake
is fixed to the lower surface of the stationary plate 1, and a large gear 7a directly connected to the motor 7 meshes with one of the racks 5' via a pinion 6', and further engages the pinion 6' via an idle gear 7'a. It meshes with the other rack 5'. Therefore, by the forward and reverse rotation of the reversible motor 7, both the racks 5', 5' move up and down at the same speed, which in turn causes the upper movable platen 2 to move up and down to move both racks 5' and 5' up and down as in the first embodiment. The molds 1a and 2a are matched, clamped, or opened.

A third embodiment will be described based on FIG.

The same reference numerals as in the first embodiment indicate the same parts, and the explanation will be omitted.

In the first and second embodiments, a relatively large capacity reversible motor is required for mold clamping. The third embodiment is a mold clamping device that uses a relatively small-capacity reversible motor or when a particularly large mold clamping force is required, the mold clamping force is applied by an upper movable platen.

9 is the upper movable plate, and the oil pipe 1 is installed in the center of the top plate.
It consists of a cylinder body 10 provided with 0a, a piston 11 that fits into the cylinder body 10, and a cylinder cover 12. A movable mold 2a is fixed to the lower surface of the piston 11, and the piston head 11
A gap δ is maintained between the peripheral edge of the lower surface of a and the edge of the inner peripheral surface of the piston cover 12 in a state where the movable mold 2a is in contact with the fixed mold 1a. Further, the cylinder cover 12 is fixed to the upper ends of the four tie bars 4, 4, 4', 4'.

Next, the effect will be explained.

First, as in the first embodiment, the reversible motors 7, 7 with brakes are rotated forward, and the upper movable platen 9 is lowered by the pinion 6 and rack 5, and the movable mold 2a is moved to the fixed mold 1a. Match the pattern to. With the reversible motors 7, 7 in a braking state, pressure oil is introduced into the cylinder body 10 and the piston 11 is actuated to increase the gap δ.
The movable mold 2a is pressed against the fixed mold 1a within the range of , and mold clamping is completed.

After the injection molding is completed, the upper movable platen 9 is raised and the cylinder body 10 is raised in the same manner as in the first embodiment.
Drain the pressure oil inside.

It goes without saying that the upper movable platen 9 having such a structure can also be used as the upper movable platen of the second embodiment.

(Effects of the Invention) As understood from the above explanation, according to the present invention, the following effects can be obtained.

(b) The height from the foundation plane to the fixed platen is slightly larger than the mold opening/closing stroke length, so the fixed mold can be installed at a lower position than the conventional model.
The work became easier and there were no problems in incorporating it into the automation process.

(b) By opening and closing the mold using a rack and pinion, the opening and closing speed could be improved.

(c) The adoption of a reversible motor with a brake prevents the upper movable platen from falling due to its own weight even if the mold is left open for a long time, thereby preventing mold damage accidents.

(d) Large flow rates of hydraulic oil are no longer required.

In addition to the above-mentioned effects, in the second invention, the tightening force is obtained by the piston, so that the reversible motor with a brake can be made smaller.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway front view showing the first embodiment of the present invention in the mold open state, FIG. 2 is a front view similarly showing the mold clamping state, FIG. 3 is a bottom view of the same, and FIG. The figure is a partially cutaway front view showing the second embodiment, and the fifth figure is a partially cutaway front view showing the second embodiment.
The figure is a sectional view taken along the - line in Fig. 4, and Fig. 6 is a sectional view taken along the line -3 in Fig. 4.
A partially cutaway front view showing the mold matching state of the embodiment,
FIG. 7 is a partially cutaway front view showing a conventional example of a mold clamping device for a vertical injection molding machine. 1: Fixed plate, 1a: Fixed mold, 2, 9: Upper movable plate, 2a: Movable mold, 3: Lower movable plate, 3a:
Square hole, 4, 4': tie bar, 5, 5': rack,
6, 6': Pinion, 7: Reversible motor with brake,
7a: Large gear, 7'a: Idle gear, 8: Connecting plate,
10: Cylinder body, 11: Piston, 11a:
Piston head, 12: Cylinder cover, 20:
Base, L: Foundation plane.

Claims (1)

[Scope of Claims] 1. In a mold clamping device for a vertical injection molding machine in which an upper movable plate to which a movable mold is fixed is moved up and down with a tie bar with respect to a fixed plate to which a fixed mold is fixed, the lower surface side of the fixed plate A rack or pinion is fixed to the rack, a pinion that meshes with the rack or a rack that meshes with the pinion is fixed to the tie bar side, a reversible motor with a brake is provided to drive the pinion, and the motor is rotated in the forward or reverse direction. A mold clamping device for a vertical injection molding machine, characterized in that an upper movable platen is moved up and down with respect to a fixed platen. 2. A mold clamping device for a vertical injection molding machine according to claim 1, wherein a rack having teeth on both sides is provided on the fixed plate, and a pair of pinions meshing with the rack are provided on the tie bar side. 3. A mold clamping device for a vertical injection molding machine according to claim 1, wherein a pair of racks are provided on the tie bar side, and a pair of pinions that mesh with the racks are provided on the fixed platen side. 4. In the mold clamping device of a vertical injection molding machine, in which the upper movable platen on which a movable mold is fixed is moved up and down with a tie bar relative to the fixed platen on which a fixed mold is fixed, a rack or pinion is fixed to the lower side of the fixed platen. A pinion that meshes with the rack or a rack that meshes with the pinion is fixed to the tie bar side, a reversible motor with a brake is provided to drive the pinion, and a cylinder is formed in the upper movable plate to fit the piston, A movable mold is fixed to the lower surface of the piston, and the motor is rotated in the forward or reverse direction to move the upper movable plate up and down relative to the fixed plate, and pressure oil is introduced into the cylinder to complete mold clamping. Features a mold clamping device for vertical injection molding machines. 5. A mold clamping device for a vertical injection molding machine according to claim 4, wherein a rack having teeth on both sides is provided on the fixed plate, and a pair of pinions meshing with the rack are provided on the tie bar side. 6. A mold clamping device for a vertical injection molding machine according to claim 4, wherein a pair of racks are provided on the tie bar side, and a pair of pinions that mesh with the racks are provided on the fixed platen side.