JPH0530903Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to an ejection device for releasing a molded product from a mold using an electric motor as a drive source in a molding machine such as an injection molding machine or a die-casting machine.

[Prior Art] As described in Japanese Patent Laid-Open No. 58-167143, an electric ejecting device converts rotational motion by an electric motor into linear motion by mechanical means such as a pinion and a rack, and transfers it to an ejecting rod. The protruding rod is moved forward and backward by rotating the electric motor in forward and reverse directions.

[Problems to be solved by the invention] In such a conventional device, the forward and backward movement of the protruding rod is switched by switching the rotation direction of the electric motor, so when switching, the inertia of the motor rotor causes startup and stopping. Especially when ejecting is performed multiple times in a row, switching takes time, and the ejecting operation takes a long time, which leads to a longer molding cycle. .

One possible way to solve this switching problem is to use a servo motor with excellent responsiveness instead of a normal electric motor, but since servo motors are more expensive than general-purpose electric motors, the machine cost is prohibitive. There is a problem.

This invention was conceived from the above circumstances, and its purpose is to use a normal electric motor as a drive source for the protrusion, but to be able to switch the forward and backward movement of the protrusion rod without having to rotate the motor in the forward and reverse directions. An object of the present invention is to provide an ejecting device with a new configuration that can shorten ejecting operation time.

[Means for Solving the Problems] The feature of this invention for the above purpose is that in a molding machine in which a movable plate is provided to move forward and backward with respect to a fixed plate, and a mold is attached to the fixed plate and the movable plate, A protruding rod is provided on the back of the board and is constantly pressed backwards by a spring member, and a protruding rod is installed at the rear of the protruding rod that converts rotational motion by an electric motor on the movable board side into linear motion, and that resists the spring member. A rotating shaft of the member and an output shaft of an electric motor are connected via an electromagnetic clutch so as to be freely movable toward and away from each other.

[Operation] The protruding rod is always in the retracted position due to spring pressure, but when the output shaft of the electric motor and the rotating shaft of the transmission member are connected by the electromagnetic clutch, the rotational force of the electric motor is applied to the member via the rotating shaft. The rotary motion is converted into a linear motion by the member, and the protruding rod is moved forward against the spring pressure to eject the molded product.

In addition, if the electromagnetic clutch is removed while the motor continues to rotate, and the communication between the output shaft and the rotating shaft is cut off, the members together with the rotating shaft will be free, and the protruding rod will immediately return to its original retracted position due to spring pressure. .

[Example] Next, the structure and operating state of this invention will be explained in detail by taking an ejection device of an injection molding machine as an example.

In FIGS. 1 and 2, reference numerals 1 and 2 are stationary plates provided on the machine base, which are integrally connected by a plurality of tie bars 3, 3.

Reference numeral 4 denotes a movable plate, which is inserted into and supported by tie bars 3, so that it can move forward and backward with respect to the one fixed plate 1. Molds 5 and 6 are attached to the movable platen 4 and the fixed platen 1, respectively.

In addition, the movable platen 4 has a screw shaft 7 connected to the back, and a rotary cylinder 8 of the other fixed plate 2 screwed with the screw shaft 7.
The rotary cylinder 8 is moved forward and backward by an electric motor 11 which rotates through gears 9 and 10.

A protruding rod 12 is provided on the back of the movable platen 4 in parallel with the tie bars 3, 3. A flange 14 is provided at the center of the protruding rod 12, and the protruding rod 12 is always pressed to a rearwardly retracted position by a spring member 15 that abuts the front part of the flange 14 and the movable plate side.

Also, at the rear of the flange 14 of the protruding rod 12,
A member is provided that converts rotational motion into linear motion and moves the protruding rod 12 forward.

In the embodiment shown in FIG. 1, a pinion rack converts rotational motion into linear motion. A rack 13 is carved on the side surface of the shaft portion extending to the rear of the protruding rod 12, and a pinion 17 having a rotating shaft 16 meshes with the rack 13.

The pinion 17 is rotatably supported on the movable platen side, and one end of the rotating shaft 12 is connected to the output shaft 20 of an electric motor 19 attached to the outside of the movable platen 4 via an electromagnetic clutch 18 of a conventional structure. There is.

The electromagnetic clutch 18 has an armature 18a.
The armature 18a and rotor 18b are fixedly attached to the shaft end of the rotating shaft 16 and the rotor 18b to the output shaft 20, and although the armature 18a and rotor 18b are shown schematically in the open state in the drawing, they are always in the continuous state. The clocking time of the timer activated by the forward position confirmation signal of the protruding rod 12 is released, and the clocking time of the timer activated when the mold opening is completed is released by stopping the rotation of the electric motor 19, which is energized. ing.

Note that 21 is a brake for the rotating shaft 16, and 22 is a protruding pin, which protrudes from a protruding plate 24 provided inside the mold 6 with a spring member 23 acting thereon.

In the ejection device having the above structure, the molds 5 and 6 are closed by the advance of the movable platen 4, and strong mold clamping is performed to inject resin into the mold.After the resin is cooled, the movable platen 4 When the mold is opened by retreating to a predetermined position, the electric motor 19 is activated and the output shaft 20 is rotated.

Since the output shaft 20 is connected to the rotating shaft 16, the pinion 17 rotates together with the rotating shaft 16. Further, since the rotational motion is converted into linear motion by the rack 13, the protruding rod 12 moves forward against the spring pressure, presses the protruding plate 24 in the mold together with the spring member 23, and the protruding pin 22 Push the tip out of the mold. As a result, the molded product 25 attached to the mold surface of the mold 6 is released.

When the ejection of the molded product 25 is completed as described above, the electromagnetic clutch 18 is released, and the rotating shaft 16 and the output 20 are separated from each other, and the protruding rod 12 is in a free state. As a result, the pinion 17 is rotated in the opposite direction and immediately returns to its original position to complete the ejection process.

Therefore, when it is necessary to repeat the ejection several times, the rotation of the electric motor 19 remains as it is, and the ejection rod 12 is operated in the forward and backward positions via the electromagnetic clutch 18 and the spring. The retraction operation by the member 15 may be alternately performed, and the number of protrusions can also be determined by the electromagnetic clutch 18.
The number of switching times can be set arbitrarily by simply controlling electrically.

Next, the embodiment shown in FIG. 2 shows a case where rotational motion is converted into linear motion by a screw shaft and a rotating cylinder.

In this case, a screw shaft 26 is attached to the rear of the protruding rod 12.
The threaded shaft 26 and a rotary tube 27 rotatably supported on the movable platen are screwed together via a large number of balls, and a gear 28 provided on the outer periphery of the rotary tube 27 is connected to the rotary shaft. meshing with gear 29 of 16,
The rotational force of the electric motor 19 is transmitted through the electromagnetic clutch 18.

The rotational force transmitted to the rotating cylinder 17 is transmitted to the screw shaft 26
This is converted into a linear motion by the electric motor 19, and the protruding rod 12 is moved forward by the electric motor 19.

[Effects of the invention] As mentioned above, this invention converts the rotational motion by the electric motor on the movable platen side into linear motion at the rear of the protruding rod provided at the back of the movable platen by constantly pressing backwards with a spring member. In addition, a member is provided that moves the protruding rod forward against the spring member, and the rotating shaft of the member and the output shaft of the electric motor are connected to each other via an electromagnetic clutch so that the spring pressure and the rotational force of the electric motor can be adjusted. By moving the protruding rod back and forth, the following effects are achieved.

Since the forward movement of the protruding rod can be performed by an electric motor, and the backward movement can be performed by a spring pressure, there is no need to switch the rotation direction as in the conventional method while using an electric motor as a drive source.
Since there is no need to stop or start the rotation of the electric motor during switching, the switching is completed almost simultaneously with the operation of the electromagnetic clutch, and the time required for switching is shorter than in conventional devices.

The ejecting rod, which is compressed by the spring pressure, moves all at once to the retracting limit by switching with the electromagnetic clutch, so the switching time is shortened, and the ejecting operation can be completed quickly. The time is significantly shortened, and the molding cycle is also shortened accordingly.

The forward and backward movement is switched by controlling the actuation timing and operation time of the electromagnetic clutch, resulting in good responsiveness and the amount of movement can be freely controlled, making it possible to adjust the amount of backward movement of the ejector rod during multi-step ejection work. The retraction time can be minimized and the time required for one ejection process can be further shortened.

The ejection speed of the ejector rod, which is moved forward by an electric motor, can be set according to the molded product and molding condition by controlling the rotational speed of the motor. It won't hurt anything.

Since a general-purpose electric motor can be used as the ejection drive source, the ejection device costs less than when using an expensive servo motor, and the structure is not particularly complicated, making it easier to use than conventional molding machines. It also has the advantage of being widely available.

[Brief explanation of the drawing]

The drawings schematically show an embodiment of the ejecting device in a molding machine according to this invention, and FIG. 1 is a longitudinal sectional side view of the first embodiment, and FIG. 2 is a longitudinal sectional side view of the second embodiment. 1, 2...Fixed plate, 3...Diver, 4...Movable plate, 5, 6...Mold, 12...Protruding rod, 13...
...Rack, 15... Spring member, 16... Rotating shaft,
17... Pinion, 18... Electromagnetic clutch, 19
...Electric motor, 20...Output shaft, 26...Screw shaft,
27... Rotating cylinder, 28, 29... Gears.

Claims (1)

[Scope of utility model registration request] In a molding machine in which a movable platen is provided to move forward and backward with respect to a fixed platen, and a mold is attached to the fixed platen and the movable platen, a protruding rod is provided on the back of the movable platen so as to be constantly pressed backward by a spring member, At the rear of the protruding rod,
A member is provided that converts the rotational motion by the electric motor on the movable plate side into linear motion and moves the protruding rod forward against the spring member, and the rotating shaft of the member and the output shaft of the electric motor are connected via an electromagnetic clutch. An ejecting device for a molding machine, characterized in that the ejecting device is connected so as to be freely accessible and detachable.