JPH0655593A - Injection molding machine - Google Patents

Abstract

PURPOSE:To provide an injection molding machine, in which a weighing screw can be extracted backward and the weighing screw is exchanged simply and safely in an injection unit. CONSTITUTION:An injection unit has a front plate, a pusher plate 3 and a rear plate 4. The base section of a weighing screw 8 arranged along an injection axis is mounted detachably to the screw sleeve 6 of the pusher plate 3 by a screw key 21. The screw key 21 is penetrated into the screw sleeve 6 in the radial direction, and engaged with the base section of the weighing screw 8. The screw key 21 fixs the axial movement of the weighing screw 8. A through- hole, in which the weighing screw 8 can be passed extending over the screw sleeve 6 and the rear plate 4, is formed while using the injection axis (a) as an axis.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-line type injection unit for an injection molding machine.

[0002]

2. Description of the Related Art FIG. 6 shows an example of an in-line type injection unit 1 in an injection molding machine.
The pusher plate 3 is provided with a pusher plate 3 and a rear plate 4, and the pusher plate 3 is slidably attached to a tie rod 5 that connects the front plate 2 and the rear plate 4 and is movable back and forth. The injection unit 1 is an electric type.

In the injection unit 1, a screw sleeve 6 is rotatably supported on the front side of the pusher plate 3 and a ball nut 7 is fixed on the rear side thereof. These are arranged with their axes aligned with the injection axis a (the center line of the direction in which injection is performed), and the screw sleeve 6 is provided with a base portion 9 of the measuring screw 8 arranged so as to penetrate the front plate 2 and a screw bush 10. And retainer 11
It is fixed in the axial direction and the rotation direction via.

The measuring screw 8 is mounted on a cylinder 12 fixed to the front side of the front plate 2, the base 9 and the screw bush 10 are spline-fitted, and the retainer 11 has a half-divided structure and a front step of the base 9. Engage the part. Also, the ball nut 7 has a rear plate 4
The front portion of the ball screw 14 which is pivotally supported by and is driven by the injection servomotor 13 (FIG. 6) is screwed.

Reference numeral 15 is a measuring pulley fixed to the screw sleeve 6, and is driven by a measuring servomotor 16 attached to the pusher plate 3.

When the measuring screw 8 is driven and rotated through the measuring servomotor 16 and the measuring pulley 15, the resin for injection is measured, kneaded and melted.
Then, the pusher plate 3 is moved forward through the injection servomotor 13 and the ball screws and nuts 14 and 7, so that the resin melted by the measuring operation is injected into the mold.

[0007] Conventionally, when it is necessary to replace the measuring screw 8 for inspection or replacement, first, the injection unit 1 is retracted and purged, and then the retainer is removed from the screw sleeve 6 in the pusher plate 3. 11 and the screw bush 10 are removed. As a result, the base portion 9 of the measuring screw 8 is released from the pusher plate 3. Next, the entire injection unit 1 is horizontally rotated (swivel), the nozzle 17 and the nozzle adapter 18 at the tip of the cylinder 12 are removed, and the measuring screw 8 is pulled out from the front of the cylinder 12.

For this reason, the conventional replacement work of the measuring screw 8 is troublesome, and when pulling out the measuring screw 8, the front portion of the measuring screw 8 which is at a high temperature must be gripped, which is dangerous. . Further, if the molten resin remains inside the cylinder 12, the resin adheres to the spline of the base portion 9 when the measuring screw 8 is pulled out forward, and therefore it is also necessary to remove it.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides a simple and easy replacement of a metering screw in an injection unit, and
The challenge is to provide a safe injection molding machine.

[0010]

[Means for Solving the Problems] An injection unit,
It has a front plate, pusher plate and rear plate. A metering screw is arranged along the injection axis and its base is removably attached to the screw sleeve of the pusher plate by means of a screw key.

The screw key penetrates the screw sleeve in the radial direction and engages with the base portion of the measuring screw to fix the axial movement of the measuring screw. A through hole through which the measuring screw can pass is provided across the screw sleeve and the rear plate with the injection axis a as the axis.

In an electric injection unit, a ball screw of a ball screw / nut mechanism that moves a pusher plate in the front-rear direction may be formed with a detaching hole through which a measuring screw can pass. The electric injection unit moves the pusher plate back and forth by a plurality of ball screw / nut mechanisms pivotally supported between the front plate and the rear plate, and the axis lines of these ball screws are placed at symmetrical positions about the injection axis a. It may be arranged configuration.

[0013]

Operation: The screw key allows the measuring screw to be attached to and detached from the injection unit. A through hole provided over the screw sleeve and the rear plate enables the measuring screw to be pulled out rearward.

[0014]

1 to 3 show parts of a pusher plate 3 and a rear plate 4 of an injection unit 1 in an injection molding machine. For structures similar to those of the conventional art, the same reference numerals as those described above are used and detailed description thereof is omitted. . The injection unit 1 is of an electric type, and its operation is controlled by a numerical controller as a part of the injection molding machine as in the conventional case. That is, the injection servomotor 13 and the metering servomotor 16 are under the control of the numerical controller.

On the pusher plate 3, a screw sleeve 6 has its axis aligned with the injection axis a and the bearing 1
It is rotatably attached via 9. A ball nut 7 is fixed to the rear surface side of the pusher plate 3 via a load cell 20. Load cell 20
Is for detecting a back pressure and an injection pressure necessary for controlling the injection molding machine.

The front part of the screw sleeve 6 projects toward the front side of the pusher plate 3, the metering pulley 15 is fixed to the front part, and the insertion hole 22 for mounting the screw key 21 (FIG. 2) is formed in the radial direction. Are formed on the top and bottom. The screw sleeve 6 has a hollow cylindrical shape and has an insertion hole 23 into which the base portion 9 of the measuring screw 8 is attached at the front portion, and a large-diameter insertion hole 24 into which the front end of the ball screw 7 is inserted at the rear portion. On the inner surface of the insertion hole 23, a spline that fits with a spline provided on the base of the measuring screw 8 is engraved. Insertion hole 23 and insertion hole 2
The axis of 4 corresponds to the emission axis and they are continuous.

The measuring screw 8 has the largest diameter throughout the entire length of the base 9 on which the spline is engraved.
Has a circular groove formed by a flange 25 and a small diameter portion 26 at its rear end. A tap hole 27 is formed at the center of the rear end surface of the measuring screw 9 (Fig. 7). The screw key 21 has a tubular shape in which a front wall 28 and a rear wall 29 are surrounded by side walls 30 on both sides, and the lower end of the front wall 28 is cut out in a semicircular shape so as to match the small diameter portion 26 and forms an annular groove. The rear wall 29 contacts the rear surface of the flange 25. That is, when the upper and lower screw keys 21 and 21 are mounted, the flange 25 is captured and restrained inside thereof. The attached screw key 21 is fixed to the screw sleeve 6 by a bolt 31 (FIG. 1) inserted from the front.

A ball screw 14 is rotatably supported on the rear plate 4 via a bearing 32 with its axis aligned with the injection axis a. The ball screw 14 is screwed into the ball nut 7 fixed to the rear surface of the pusher plate 3 to form a ball screw / nut mechanism, and the front portion thereof enters the fitting hole 24 of the screw sleeve 6. The rear portion of the ball screw 14 projects rearward of the rear plate 4,
An injection pulley 33 is fixed to that portion, and this pulley 33 is driven by the injection servomotor 13. The ball screw 14 is also hollow and tubular and has an injection axis a.
A detachment hole 34 is provided from the front end to the rear end.

After all, the insertion hole 23 of the screw sleeve 6
And the fitting hole 24 and the attaching / detaching hole 34 in the ball screw 14.
Through holes through which the measuring screw 8 can pass through the screw sleeve 6 and the rear plate 4 are formed with the injection axis a as the axis.

In the above structure, in the measuring step, the measuring screw 8 is rotated through the measuring servomotor 16, the measuring pulley 15 and the screw sleeve 6 to measure, knead and melt the injection resin. Also,
In the injection process, the pusher plate 3 is moved through the injection servomotor 13 and the ball screw / nut mechanism 14, 7.
Is moved forward, and the resin melted in the measuring step is injected into the mold.

In the measuring process, the transmission of the rotation to the measuring screw 8 is transmitted through the spline fitting between the screw sleeve 6 and the base portion 9 of the measuring screw 8.
Further, the application of the back pressure necessary for the measuring process is transmitted to the measuring screw 8 via the pusher plate 3, the screw sleeve 6 and the screw key 21 by applying a light load to the injection servomotor 13.

Further, in the injection process, the rotational force of the injection servomotor 13 is converted into a linear motion by the ball screw / nut mechanisms 14 and 7, and the measuring screw 8 is passed through the pusher plate 3, the screw sleeve 6 and the screw key 21. Be transmitted to.

When replacing the measuring screw 8, the nozzle touch is released to retract the injection unit 1 and, after purging, the fixation with the bolt 31 (FIG. 1) is first released, and the screw key 21 is attached to the screw sleeve. Remove from 6. Then, the tip of the extraction tool 35 is inserted from the rear end side of the ball screw 14, the screw part of the tip is screwed into the tap hole 27 formed in the rear end surface of the measuring screw 8, and the measuring screw 8 is pulled out rearward. . The mounting of the measuring screw 8 is the reverse operation.

As described above, the attaching and detaching of the measuring screw 8 is easy, and there is little risk that the worker will come into contact with the high temperature portion. Further, the base portion 9 of the measuring screw 8 is the cylinder 1
Since it does not pass through the inside of 2, the base portion 9 of the measuring screw 8
Can be made thick and sturdy. In addition, FIG. 4 is a second embodiment in which residual resin does not adhere to the base portion 9. The electric injection unit 1 includes the front plate 2
Ball screws 14 pivotally supported between the rear plate 4 and the rear plate 4
The pusher plate 3 is attached via a ball nut 7, and the pusher plate 3 is moved in the front-rear direction by a plurality of ball screw / nut mechanisms. The plurality of ball screws 14 are arranged in symmetrical positions about their axes about the injection axis a.

A base 9 of the measuring screw 8 is attached to the screw sleeve 6 by spline fitting, and is engaged in the direction of the injection axis a by screw keys 21 and 21. The screw sleeve 6 has only the insertion hole 23 and does not need the insertion hole 24. In addition, an attachment / detachment hole 37 that communicates with the insertion hole 23 is formed in the boss portion 36 of the pusher plate 3 on which the screw sleeve 6 is axially supported and the central portion of the rear plate 4, and is connected to the insertion hole 23. There is. That is, the screw sleeve 6 and the rear plate 4
A through hole through which the measuring screw 8 can pass is provided with the injection axis a as the axis.

When replacing the measuring screw 8,
Purging is performed in the same manner as in the above example, and the screw key 2
After removing 1 and 21, the tip of the extraction tool 35 is screwed into the rear end surface of the measuring screw 8 from the rear of the rear plate 4 through the attachment / detachment hole 37 and the insertion hole 23. The mounting of the measuring screw 8 is the reverse operation. In the case of this embodiment, a through hole is not required inside the ball screw 14, the ball screw 14 is inexpensive, and the pusher plate 3 is used.
Detachment hole 3 in boss portion 36 and rear plate 4 of
7 can be formed large, and since there are relatively few members between the pusher plate 3 and the rear plate 4, the measuring screw 8 can be easily attached and detached.

The above is an embodiment, and the invention of the present application is not limited to the illustrated specific configuration. Screw key 2
1 is a screw sleeve 6 and a measuring screw 8
It suffices that the base 9 of the screw is engaged and attached so as not to fall off. Therefore, after inserting the screw key into the insertion hole 22 of the screw sleeve 6, the plurality of screw keys 21 are fixed to each other to be attached. It may be by means. The present invention can be adopted for the attachment and detachment of the measuring screw 8 even when the injection unit 1 does not use the ball screw / nut mechanism as the injection mechanism. The ball screw / nut mechanism may be driven on the nut side. The engagement between the measuring screw 8 and the extraction tool 35 is not limited to the screw-in type.

[0028]

As described above, it is possible to easily and safely attach and detach the measuring screw in the injection unit. Residual resin does not adhere to the spline part of the measuring screw, reducing the time and effort required for removal work. The structure for the horizontal rotation (swivel) is not required on the injection unit side, and the structure of the injection unit is simplified. The base of the measuring screw can be thick and strong.

[Brief description of drawings]

FIG. 1 is a front view of a main part shown in cross section.

FIG. 2 is a perspective view of a main part (partial cross section).

FIG. 3 is a front view showing a state where the measuring screw is pulled out.

FIG. 4 is a front view (partial cross section) showing another embodiment.

FIG. 5 is a front view showing a main part of a conventional example.

FIG. 6 is a front view (partial cross section).

FIG. 7 is a front view (partial cross section).

[Explanation of symbols]

1 Injection Unit 2 Front Plate 3 Pusher Plate 4 Rear Plate 6 Screw Sleeve 7 Ball Nut 8 Measuring Screw 9 Base 14 Ball Screw 21 Screw Key 23 Insertion Hole 24 Fitting Hole 34 Desorption Hole 35 Extraction Tool

Claims (3)

[Claims] 1. In an injection unit equipped with a front plate, a pusher plate and a rear plate, the base of a measuring screw arranged along the injection axis line penetrates into the screw sleeve of the pusher plate and radially penetrates the screw sleeve. A through-hole that is detachably attached by a screw key that engages with the base of the screw and fixes the axial movement of the measuring screw, and has a through hole through which the measuring screw can pass across the screw sleeve and the rear plate with the injection axis a as the axis. An injection molding machine featuring. 2. A screw sleeve is arranged on the front surface side of the pusher plate, and a ball screw / nut mechanism is arranged on the rear surface side with the injection axis a as the axis, and the ball screw / nut mechanism moves the pusher plate in the front-rear direction. 2. The injection molding machine according to claim 1, wherein the injection molding machine is an electrically driven injection unit, wherein a detachment hole through which a measuring screw can pass is formed by penetrating a ball screw. 3. An electric injection unit in which a pusher plate is moved in the front-rear direction by a ball screw / nut mechanism, wherein the pusher plate has a plurality of ball screws axially supported between a front plate and a rear plate. The injection molding machine according to claim 1, wherein the injection molding machine is mounted via a nut, and the axis of the ball screw is arranged at a symmetrical position about the injection axis a.