JPH06238705A - Device for inserting insert - Google Patents

Abstract

PURPOSE:To provide a device for inserting into a mold an insert which is used to automate work for inserting the rotation axis of the rotor of a stepping motor when the rotor is produced by injection molding. CONSTITUTION:In a device for inserting an insert, a tapered face 20 is provided in the center of the top part of a floating body 15 received by thrust bearings 16. A tapered shaft 21 is engaged with the tapered face 20. A mold inserting part 17 is formed in the center of the lower end of the floating body 15. The mold inserting part 17 is slightly smaller than the inside diameter of the cavity of a mold and has a tapered face 19 in the external circumferential face of the lower end. A hole is provided in the center of the floating body 15 and the tapered shaft 21. The force rod 24 of an insert pin is penetrated through the hole.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an insert insertion device for injection molding work.

[Prior art]

An injection-molded product 1b of a small stepping motor rotor as shown in FIG. 8 is molded by setting a rotary shaft 1a (hereinafter, insert pin) in a mold in advance and injecting a resin containing a magnetic material. By doing so, the final product is finished at once.

FIG. 9 shows a die cross section of this molded body. The insert pin 1a is set in advance in the insert pin fitting hole 3 of the lower mold 2, the upper mold 4 is closed, and the melted resin is injected from the runner 5 into the mold cavity 6 at high pressure to form a molded body. . The lower die 2 is provided with an eject pin 7 that pushes out the molded body 1b. The lower mold 2 is a turntable 9
It is installed in the same number as the index.

What is important in this molding operation is to increase the runout and concentricity of the insert pin 1a and the molded body 1b, and to attach resin and burrs to the insert pin 1a of the bearing mounting portions 28 at both ends of the molded body 1b. Is to prevent it from happening. In order to increase the runout and concentricity of the molded body and to suppress burr adhesion on the insert pin 1a,
It is necessary to reduce the gap between the insert pin 1a and the insert pin fitting hole 3. Specifically, 0.015
It is necessary to hold the gap within 0.020 mm or less.

As an apparatus for injection molding such shaped parts, a vertical injection molding machine 8 having a turntable 9 capable of indexing 2 to 4 stations shown in FIG. 10 is generally used. Further, the turntable 9 is provided with the steps of insert insertion 10, mold closing 11, mold injection of the molded body, cooling 12, and removal of the molded body 13.

On the other hand, the position of the lower mold 2 attached to the injection molding machine turntable 9 varies due to variations in the indexing accuracy of the injection molding machine, errors in mounting the mold on the turntable, errors in manufacturing the mold, and the like. Actually, about 0.05mm is inevitable. For this reason, it was difficult to automate the insert pin insertion work with tight tolerances such as this time between the insert pin and the insert pin fitting hole of the mold, and it depended on manpower.

[0007]

According to the present invention, when the positional deviation of the die mounted on the turntable 9 is larger than the tolerance between the insert pin 1a and the insert pin fitting hole 3, this insert work is performed. An object of the present invention is to provide a device capable of automating.

[0008]

In order to solve the above-mentioned problems, an insert insertion device 14 having a structure for floating a horizontal surface is used to position the insert pin 1a so as to follow the mold cavity surface 6 serving as a reference for insertion. It is composed of a device for performing.

[0009]

With the insert insertion device 14 of the present invention, even if there is a variation in the indexing accuracy of the injection molding machine, a die mounting error on the turntable, or a die position variation on the turntable due to a die manufacturing error. The insert pin insertion work can be automated by using a commercially available robot.

[0010]

1 and 2 show a cross section of an insert pin inserting device 14 of the present invention. The floating body 15 has a cylindrical shape and is supported by thrust bearings 16 at the top and bottom.
It is designed to float lightly on a horizontal surface. In the lower part, a cylindrical mold insertion part 17 is provided. At the center of the die insertion part 17, the insert pin 1a
A hole slightly larger than the outer diameter of the insert pin 1a is provided, and a stopper 18 for preventing the insert pin 1a from falling is provided on the way. The size Y of the taper surface 19 at the lower end of the die insertion portion is set to be a half or more of the total value of the positioning variation of the die attached to the turntable and the positioning variation of the robot, and is a smooth taper. It is sufficient to provide the Y dimension of about 0.5 mm.

A conical taper surface 20 is provided on the upper side of the floating body 15, and a taper shaft 21 fitted to this taper surface is attached by an air cylinder 22 or the like so that it can be moved up and down. When the gap 23 is provided between the taper shaft 21 and the floating body 15, the floating body 15 can be kept horizontal and floating by an amount proportional to the gap. This floating amount 23
Needs to be set to be a little larger than the sum of the mold position variation and the robot positioning variation. Further, the taper shaft 21 is connected to the conical taper surface 20 of the floating body 15.
When pressed against, the floating body 15 will
When the robot teaching is performed in this state, the robot teaching position is aligned with the center of the floating body 15.

The taper shaft 21 and the floating body 15,
A hole penetrates through the center of the mold insertion portion 17, and an insert pin pushing rod 24 is provided. This push rod 2
The air cylinder 25 moves up and down to push the insert pin 1a into the insert fitting hole 3.

A procedure for inserting the insert pin 1a into the lower mold 2 mounted on the turntable using the insert inserting device 14 of the present invention will be described with reference to FIGS. The insert pin 1a is previously inserted into the mold insertion portion 17 by another device. The robot 26 brings the insert insertion device 14 directly above the center of the lower mold 2 cavity as shown in FIG. In this state, an error X in position shift of the central axis occurs due to the positional deviation of the mold and the positional accuracy of the robot.

Since the die insertion portion 17 is provided with a taper surface dimension Y which is equal to or larger than the above X displacement error, the robot 2
6, when the insert insertion device 14 is slowly lowered, the mold cavity upper surface 27 and the mold insertion portion taper surface 19
a comes into contact, and a force that moves the floating body 15 toward the center of the mold cavity 6 acts (FIG. 4). At this time, since the floating body 15 is lightly held by the bearing 16 or the like, the mold cavity 6 can be smoothly moved without giving excessive force to the robot arm 26 and the insert insertion device 14.
Inserted in. In the device manufactured by using commercially available Bayerin for the thrust bearing 16, the horizontal plane is maintained at a few grams and floating is performed, and the gap between the mold insertion portion 17 and the mold cavities 6 is 0.01 mm, and the mold cavity surface is not scratched smoothly. I was able to insert it (Fig. 5).

Since the insert pin fitting hole 3 is accurately formed in the center of the mold cavity 6, the center of the mold inserting portion 17 inserted into the lower mold 2 is aligned with the core of the insert pin fitting hole 3. Fit. When the insert pin push rod 24 is pushed down in this state, as shown in FIG.
Is pushed into the insert pin fitting hole 3. If the position of the push-in end of the insert pin push-in rod 24 is detected, it can be confirmed whether the insert pin 1a is reliably set in the insert fitting hole 3, which is useful for preventing damage to the mold.

In the actual injection molding operation, a large number of pieces can be formed by one die in order to improve productivity. In the case of this large number of pieces, it is difficult to teach the robot, and it is difficult to align the robot, and the mechanical precision of the mold and the injection molding machine must be improved. Even in such a case, as shown in FIG. 7, if the insert insertion device 14 of the present invention is attached to the arm of the robot by the number of molded bodies, the automation of the insert operation is easy.

[0017]

As described above, even in the injection molding work where it is difficult to insert the insert pin, the insert work can be automated without using a device combining a high performance robot and image processing. Further, it is not necessary to re-teaching for each die or when exchanging the dies, and the setup time can be shortened. Furthermore, by monitoring the descending end of the insert pin pushing rod, it was possible to detect an insert insertion error, and it was inserted more reliably, and there was no damage to the die.

[0018]

[Brief description of drawings]

FIG. 1 is a sectional view of an insert insertion device of the present invention.

FIG. 2 is an overall view of the insert insertion device of the present invention.

FIG. 3 is a diagram showing an insert pin insertion procedure using the device of the present invention.

FIG. 4 is a diagram showing an insert pin insertion procedure using the device of the present invention.

FIG. 5 is a diagram showing an insert pin insertion procedure using the device of the present invention.

FIG. 6 is a diagram showing an insert pin insertion procedure using the device of the present invention.

FIG. 7 is a diagram in which two insert insertion devices of the present invention are attached to the tip of the robot.

[Figure 8] External view of insert molding

FIG. 9 is a mold cross-sectional view of an insert molded body

FIG. 10 is a schematic view of a 4-station indexing vertical injection molding machine.

[Explanation of symbols]

 1a Insert Pin 1b Molded Body 2 Lower Mold 3 Insert Pin Fitting Hole 4 Upper Mold 6 Mold Cavity 9 Turntable 10 Insert Insert 14 Insert Insertion Device 15 Floating Body 16 Thrust Bearing 17 Mold Insert 19 Tapered Surface 20 Conical Taper Surface 21 Tapered shaft 23 Gap 24 Pushing rod 26 Robot 27 Mold cavity upper surface edge

Claims (1)

[Claims] 1. A taper surface is provided in the center of the upper end of the floating body received by the thrust bearing, and a taper shaft fitted to the taper surface and a center of the lower end of the floating body are slightly smaller than the inner diameter of the mold cavity and the outer circumference of the lower end. An insert inserting device, which is composed of a mold inserting portion having a tapered surface, and has a hole through which an insert pin pushing rod penetrates at the center of the floating body and the tapered shaft.