JPS59187826A - Mold clamping method of molding machine - Google Patents

Abstract

PURPOSE:To exactly hold molds controllably with high accuracy by optionally setting up the closing position of the molds by using a system in which the rotation of a servo motor is converted into propulsion force and transmitted through a threaded shaft in such a way that a movable board can be moved or held. CONSTITUTION:The rotation of a servo motor 22 is converted into a propulsion force to move a movable board 13 in the mold opening position toward the mold closing direction by a transmission mechanism from the sprocket 25 of a rotary shaft 24 to a mold clamping shaft 15. The arrival of a movable mold 14b at the mold closing position is detected by a rotation amount detector 23, an electromagnetic brake 21 is operated, and a rotary cylinder 17 is restricted with the sprocket 20. Thereby, the movable plate 13 and the movable mold 14b are also restricted together through a threaded shaft 15 and held under a condition of withstanding the injection pressure.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mold clamping method for a mold clamping device that moves a movable platen using a servo motor.

A mold clamping device using an electric motor as a driving source is already known.

However, since the electric motor used there has a constant rotation speed, a mechanical speed change means is required, and the complicated construction of the motorbag makes it difficult to accurately adjust the closing position of the mold. It was something that could not be controlled.

In addition, the serger motor can obtain a very large torque when rotating at low speed, has a large torque inertia ratio, has good responsiveness, and has a wide variable speed range, so mold clamping speed and force can be controlled electrically. For example, a mold clamping device can be used as a drive source that does not require a mechanical speed change means.

However, it is not possible to control the closing position of the mold step by step only by controlling the mold clamping speed and force, and it is difficult to hold the mold at the trench setting position. For example, arrow 1t.

In the mold clamping device, the closing position of the mold is controlled in stages,
The need for holding in a set position is required in injection compression molding, injection foam molding, and the like.

The molds are held by mechanical means when performing these moldings, and in addition to the normal mold clamping mechanism, a special mold holding mechanism is incorporated.

Therefore, the structure of the mold clamping device, the mold, etc. becomes complicated, and the mold clamping operation also requires a lot of effort.

This invention uses a military-type servo motor as the drive source of the mold clamping device, and has a transmission mechanism that converts the rotational force of the servo motor or surf motor into thrust to move the movable platen using electrical means. To provide a mold clamping force method that can control and immediately hold the closed position of a mold by controlling 17, and can perform not only ordinary injection molding but also injection compression molding, injection foam molding, and so on. It is something.

The present invention will be explained in detail below with reference to the illustrated examples. A required number of tie bars 12, 12 are constructed, and a movable platen 13 is movably attached to the tie bars 12, 2. - A fixed mold 1.4a and an ill full mold 171b are installed on the opposing surfaces of one fixed platen 11 and one movable platen 13, respectively.
%, the tf' shaft 15 is inserted into the nut-shaped bearing part 4) 18 of the rotary cylinder 17, which is rotatably inserted into the fixed platen 10 using the lower bearing 16, and By fitting a large number of spirally drawn balls 10.19 provided on the inside with the threaded grooves 15a, the rotary cylinder moves 1° in the axial direction when the rotary cylinder rotates.

Also, at the end of the rotary cylinder 17 protruding from the fixed platen 10, there is a C.
, ll1, sprocket 2 ( ) having a tooth profile is movable in the axial direction, and is separated from the stationary plate 10 and removed. An electromagnetic brake 21 is provided.

The above-mentioned electromagnetic brake 21 has a structure generally referred to as a hysteresis brake, and includes an inner driver with an armature and a plurality of brake brakes 1 and 1, which are separated inside and outside. - A filled core with a built-in coil located adjacent to the main plate has a loose fit on the fixed plate 1.
0, and the armature 21b) is fixed to the side surface of the sprocket 20.

22" is a servo motor fixed horizontally inside the machine base 3, equipped with a rotation amount detector 23, and a sprocket part for fixing the tooth profile is attached to a rotating shaft 24 protruding from the side wall of the machine base. That sprocket 25 and the above sprocket 2
0 and the toothed chair 1 belt 26 or rack is a bridge.

Next, position control and holding of the mold by the mold clamping device will be explained.

In case of injection compression molding, siryl-? 'Motor 2
Rotate 2 in the forward direction. The rotational force in the surf motor 22 is transmitted from the sprocket 5 of the rotating shaft 24 to the mold clamping shaft 1-5.
Movable platen 1; 3 in the mold opening position by the transmission mechanism that leads to
is converted into a thrust force that moves in the mold clamping direction.

The rotation amount detector unit detects that the movable mold 14b has reached the preset mold closing position if A shown in FIG. The cylinder 17 is restrained. In addition, the movable platen 1:3 is also moved to the movable mold 1 via the two shafts 15.
．． 4t) and held in a state that can withstand injection pressure.

Next, molten resin 28 is injected from the injection tube 27 into the closed mold. After injection is completed, 'i15' to the electromagnetic brake 21
, the flow is cut off and the brake is applied by W1. And again (J
---The homo-ori 22 is rotated in the forward direction to move the movable mold 14b together with the movable platen 13 in the groove where the next set position B is detected by the rotation angle detector B, and Compress the resin path,
Enter the strong mold clamping process. After the molding, the ν primary motor 22 is reversely rotated to move the movable platen 13 in the mold opening direction to release the molded product.

Further, in the case of injection foam molding, contrary to the case of injection compression molding, the servo motor 22 is rotated in the forward direction until the set position ftB is detected by the rotation-cliff detector 23.
), the movable platen 13 is moved. When the set position B is detected, the servo motor 22 stops, and the movable platen 1:3 also stops in the mold closed state. At this time, the laser motor 22 is allowed to rotate freely.

Next, at the same time as injecting the foamable resin path into the mold, the electromagnetic brake 21 is activated with a predetermined current value. When the inside of the mold is filled with the resin U, the movable platen 13 generates a backward force due to the mold internal pressure, and moves in the mold opening direction together with the α and i′ shafts 15. As the U-shaft 15 moves backward, rotational force is generated in the bearing member J8. The rotational force in this bearing member 18 and the brake l/- of the electromagnetic brake 21
The force (the tt current value brake force is approximately proportional) can cause the brake to slip in a balanced manner, thereby increasing the mold volume while maintaining a predetermined pressure within the mold.

When the rotation amount detector section detects that the movable platen 13 has retreated to a predetermined position, the current to the electromagnetic brake 21 is cut off and the brake is released. Then, the ylr motor 22 is rotated forward again to perform strong mold clamping. After cooling, the serging motor 22 rotates in the opposite direction to enter the mold opening process, and the molded product is released from the mold.

In the above embodiment, the mold position is controlled by detecting the amount of rotation of the serger motor 22, but any device may be used as long as the set position is detected by electrical means. be able to. Also, the rotation amount detector part is the Zarpo motor 2.
20 may be provided on the rotation axis U, and the control may be performed by detecting the amount of rotation of the rotation means of the transmission mechanism.

Furthermore, depending on the case, the electromagnetic brake 21 may be omitted and the movable platen may be protected or restrained by the servo motor 22.

As described above, this invention moves and holds the movable plate by electrical means through a transmission mechanism using the rotational force of a servo motor, a rotation means that converts the rotational force into thrust, and a screw shaft. Therefore, when holding the movable platen, there is no need to provide a special device unlike in the case of mechanical steps. In addition, the closing position of the mold can be set arbitrarily, and the closing position of the mold can be controlled at the same time as the set position is detected, so the accuracy is higher than when done mechanically, and position control is always reliable. It has features such as being able to hold objects.

[Brief explanation of drawings]

The drawings show one embodiment of a mold clamping device used when carrying out the mold clamping method according to the present invention, and FIG. 1 is a partially longitudinal side view, and FIG. 2 is a cross section showing the setting position of the mold. It is a diagram.

Claims (1)

[Claims] A servo motor is used as the drive source for the mold clamping device, and a transmission mechanism consisting of a rotating means and a screw shaft is provided between the servo motor and the movable platen, and the movable platen is moved via the transmission mechanism, while the movable platen is 4. A mold clamping method for a molding machine whose special mission is to detect the mold clamp setting position, control the fully closed position, and hold the movable platen by electrical means.