JPH0425304Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Technical Field) The present invention relates to an in-line screw type injection device, and particularly to an in-line screw type injection device suitable for use in flow molding.

(Prior art) Generally, in-line screw type injection equipment:
When the injection material introduced into the heating cylinder is fluidized and guided forward by the rotation of the injection screw, and the injection screw is retreated to a predetermined position by the pressure of the injection material guided forward. , the injection material is measured by stopping the rotation of the injection screw. After measuring the injection material, the injection screw is moved forward to inject the measured injection material into a predetermined product cavity through the nozzle of the heating cylinder.

However, the above-mentioned normal injection molding method, in which the injection material is measured by specifying the retracted position of the injection screw, and after that measurement, the measured injection material is injected into the product cavity, This method can only be adopted when the product cavity volume of the mold is smaller than the maximum injection amount of the injection device, and cannot be adopted when the product cavity volume is larger than the maximum injection amount of the injection device.

In such cases, conventionally, a so-called flow molding method has been adopted in which the injection material sent forward by the rotation of the injection screw is directly poured into the product cavity. In order to specify the amount of injection material, a measurement method is adopted in which a timer is used to set the pouring time of the injection material by rotation of the injection screw.

(Problem) However, when performing flow molding, with conventional equipment in which the injection material is measured by time as described above, especially when the rotational drive means of the injection screw is a hydraulic motor, injection into the product cavity is difficult. There were problems such as the amount of material being fed (injection amount) was not stable and the molded products were likely to vary.

In a hydraulic motor, the flow rate of hydraulic oil changes due to changes in oil temperature and fluctuations in the torque of the injection screw, and it is unavoidable that variations in the rotation speed occur. It is inevitable that variations will occur in the amount of rotation of the injection screw within a certain period of time, and thus in the amount of injection material fed into the product cavity, resulting in variations in the molded product.

(Solution) The present invention was developed against the background of the above, and its gist is that the injection material introduced into the heating cylinder is controlled by the rotation of the injection screw, as described above. In the in-line screw type injection device, the in-line screw type injection device is configured to fluidize the fluid by the injection screw and inject it into a predetermined product cavity through the nozzle of the heating cylinder. (b) rotation amount detection means for detecting the rotation amount of the injection screw; and (c) detection by the rotation amount detection means. a metering operation stop means for comparing the rotation amount of the injection screw set by the injection amount setting means with the rotation amount of the injection screw set by the injection amount setting means, and stopping the rotation operation of the injection screw based on the fact that they match; This is because we have established this.

(Function/Effect) According to such an injection device, the amount of injection material fed into the product cavity is directly set in accordance with the rotation speed of the injection screw.
Even if a hydraulic motor, which has a variable rotational speed, is used as the rotational drive means for the injection screw, the amount of injection material fed into the product cavity (injection amount) will vary due to the variation in rotational speed.
There is no large variation in the results. Therefore, compared to conventional injection equipment, which uses a timer to specify the rotation time of the injection screw to determine the amount of injection material fed into the product cavity, the injection material can be injected more accurately and stably. This allows for stable production of highly accurate molded products.

As mentioned above, the present invention can be particularly suitably applied to an injection device that employs a hydraulic motor whose rotational speed is easily changed as a rotational drive means for the injection screw, but it is also applicable to an injection device that uses a hydraulic motor such as an electric motor or a hydraulic motor. It is also possible to apply the present invention to those employing rotational drive means other than the above.

Further, the present invention can be particularly suitably applied to an injection device that performs flow molding, but as mentioned above, the injection (feeding) of the injection material into the product cavity is performed after the injection material is measured. The present invention can also be applied to an injection device that performs ordinary injection molding. That is,
According to the injection device according to the present invention, the amount of injection material can be measured by specifying the amount of rotation of the injection screw instead of specifying the retracted position of the injection screw during normal molding.

(Example) Hereinafter, in order to clarify the present invention more specifically, one example thereof will be described in detail based on the drawings.

First, FIG. 1 is a system diagram showing one embodiment of the present invention, in which one example is a heating cylinder, and a raw material supply port 12 provided on the rear end side.
A predetermined injection material is supplied into the interior from. The injection material supplied into the heating cylinder 10 is fluidized and guided forward by the rotation of the injection screw 14, and is introduced into a predetermined product cavity (not shown) from a nozzle 16 at the front end of the heating cylinder 10. They are starting to be sent there. Note that 18 is a heating jacket disposed on the outer periphery of the heating cylinder 10.

The injection screw 14 is equipped with a gear 20 at its rear end protruding from the heating cylinder 10.
0 is engaged with a gear 24 which is rotated by a hydraulic motor 22. A rotary encoder 26 is attached to the rotating shaft 25 of this hydraulic motor 22.
is attached, and one count pulse SP is output from the rotary encoder 26 each time the hydraulic motor 22 rotates by a predetermined amount. Note that the hydraulic motor 22 is configured to move integrally with the injection screw 14 in the front-back direction. Further, the rotation of this hydraulic motor 22 is controlled by a first hydraulic circuit 28.

Further, the injection screw 14 is fixed at its rear end to a piston rod 32 of an injection cylinder 30, so that it can be moved forward and backward integrally with the piston rod 32 of the injection cylinder 30. The forward and backward movements are controlled by a second hydraulic circuit 34.

The first and second hydraulic circuits 28, 34 receive a rotation control signal SC1 from the controller 36, respectively.
The hydraulic circuits 28 and 34 receive the control signal SC2 supplied from the controller 36, respectively.
1 and SC2, the hydraulic motor 22 and the injection cylinder 30 are driven and controlled as described above.

The controller 36 also includes various setting devices necessary to drive and control the hydraulic motor 22 and the injection cylinder 30, and various switches including a manual-automatic changeover switch (none of which are shown).
is connected, and the preset counter 3
8 are connected, and various control information is inputted from these preset counters 38, setting devices, switches, etc. Then, the controller 36 supplies each control signal SC1 and SC2 to the hydraulic circuits 28 and 34, as described above, according to a predetermined program based on the control information input from these setting devices, etc. ,
A preset signal SR is supplied to a preset counter 38. As will be described later, this preset signal SR is output when a mold clamping completion signal SK is input from a mold clamping device (not shown).

Further, a preset counter 3 receives the preset signal SR from the controller 36.
An injection amount setting device 40 is connected to 8, and a preset value set by this injection amount setting device 40 is inputted. Further, the preset counter 38 is configured to receive a counting pulse SP from the rotary encoder 26. Then, in the preset counter 38,
When the preset signal SR is input from the controller 36, the preset value input from the injection amount setter 40 is preset as the count content, and the count content is also the count output from the rotary encoder 26. It is designed to be down-counted by a pulse SP, and when the input number of the counting pulse SP matches a preset value, a count-up signal SU is outputted to the controller 36.

In other words, in the preset counter 38, after inputting the preset signal SR, the rotary encoder 26
Input number of counting pulse SP from and injection amount setting device 4
When the injection screw 14 is rotated until it matches the preset value set at 0, a count-up signal SU is output to the controller 36. Therefore, after the preset signal SR is input to the preset counter 38, the rotation of the injection screw 14 is started to start the metering operation, and the preset counter 38
If the rotation operation is stopped and the metering operation is completed at the same time as the count-up signal SU is output from the machine, the amount of injection material that accurately corresponds to the preset value set by the injection amount setting device 40 can be obtained. Therefore, the preset value in the injection amount setting device 40 can be set as the rotation amount of the injection screw 14 corresponding to the desired injection amount (feeding amount) of the injection material. This makes it possible to always stably feed the injection material into the product cavity in an amount that precisely matches the desired injection amount.

Therefore, in this embodiment, the controller 36
is operated according to a program as shown in the flowchart of FIG. It is designed to accurately and stably match the set amount.

The operation of the apparatus of this embodiment will be explained below according to the flowchart shown in FIG. Here, the operation will be described in the case where flow molding is performed when the product cavity volume is larger than the maximum injection amount.

That is, when one injection molding cycle is completed, the controller 36 first executes step S1, and determines whether or not the mold clamping completion signal SK from the mold clamping device has been input. If the judgment is affirmative and it is determined that the mold clamping operation is completed, step S2 is subsequently executed, a preset signal SR is output to the preset counter 38, and the count of the preset counter 38 is The contents are preset to the preset value set by the injection amount setter 40. Also. After step 2 is completed, step S3 is executed, and a rotation control signal SC1 for starting the rotation of the hydraulic motor 22 is output to the first hydraulic circuit 28.
The hydraulic motor 22, and thus the injection screw 14, are rotated at a predetermined rotational speed. By this rotational operation of the injection screw 14, the injection material supplied into the heating cylinder 10 from the raw material supply port 12 is guided to the front of the injection screw 14, and the injection material guided to the front of the injection screw 14. is fed as it is from a nozzle 16 at the tip of the heating cylinder 10 into a product cavity (not shown).

Incidentally, at this stage, the injection screw 14 is held by a predetermined locking mechanism at a position retreated by a predetermined distance from its forward end position, and can be rotated at this holding position. ing. Here, the holding position is determined by a limit switch (not shown).

Furthermore, as is clear from the above description, in this embodiment, the metering operation of the injection device is started by executing step S3.

When the rotation of the injection screw 14 is started in step S3, step S4 is subsequently executed, and it is determined whether or not the count-up signal SU has been output from the preset counter 38.
When it is determined that the count-up signal SU has been output, a rotation control signal SC is sent to the first hydraulic circuit 28 in the following step S5.
1 is changed, and the rotational operation of the hydraulic motor 22, that is, the injection screw 14 is stopped. In other words, the operation (measuring operation) of feeding the injection material to the front of the injection screw 14 is completed.

Next, after the rotational operation of the injection screw 14 is stopped, in the subsequent step S6, the content of the advancement/retraction control signal SC2 to the second hydraulic circuit 34 is set to perform the injection operation under a predetermined pressure condition, and the hydraulic pressure is increased. Injection cylinder 30 by circuit 34
As the injection screw 14 is driven, the injection screw 14 is moved forward. That is, the injection material accumulated in front of the injection screw 14 is injected from the nozzle 16 of the heating cylinder 10 into the product cavity under a predetermined injection pressure.

Further, when this step S6 is completed, step S7 is executed, the content of the rotation control signal SC1 to the first hydraulic circuit 28 is changed, and the injection screw 14 is rotated again. As a result, the injection material is fluidized and guided forward, and the injection screw 14 is retracted by the pressure of the injection material guided forward to the holding position defined by the limit switch, and is held there. be stopped at a certain position. This completes one molding cycle.

In the mold clamping device, after the injection operation in step S6 is completed, the mold is opened after the injection material is cooled, and after the molded product is taken out, the mold clamping operation is performed.

According to such an injection device, as mentioned above,
The weighing operation based on the rotation of the injection screw 14 is started after the preset counter 38 is preset, and is completed at the same time as the count-up signal SU is output from the preset counter 38. The amount of rotation of the injection screw 14 rotated during operation accurately matches the amount of rotation (preset value) set by the injection amount setting device 40, regardless of fluctuations in the rotation speed of the hydraulic motor 22. The amount of injection material sent out in front of the injection screw 14 during injection metering always precisely matches the feed amount set by the injection amount setting device 40. Therefore, when measuring the injection material, it is possible to always stably feed the injection material in an amount that accurately matches the amount set by the injection amount setting device 40 in front of the injection material, and the injection screw 14 Compared to conventional injection equipment, which measures the injection material by setting the rotation time using a timer,
This makes it possible to stably produce highly accurate molded products.

As is clear from the above description, in this embodiment, the injection amount setting device 40 constitutes the injection amount setting means, and the rotary encoder 26 and the preset counter 38 constitute the rotation amount detection means. is configured. Also, the count up signal
A metering operation stop means is constituted by a preset counter 38 which outputs SU, and steps S4 and S5 which stop the rotation of the injection screw 14 based on the count up signal SU.

One embodiment of the present invention has been described in detail above, but
This is a literal example, and it goes without saying that the present invention should not be construed as being limited to this specific example.

For example, in the embodiment described above, the count contents of the preset counter 38 are down-counted every time the count pulse SP is input from the rotary encoder 26, and thereby the preset value of the preset counter 38 and the input number of count pulses SP are When the numbers match, the preset counter 38 outputs a count-up signal SU.
By incrementing the count contents of the preset counter 38 to the count pulse SP from the rotary encoder 26 for each input, when the preset value of the preset counter 38 and the input number of count pulses SP match, the count from the preset counter 38 is counted up. It is also possible to output the count-up signal SU.

Further, in the embodiment, the rotation amount detection means includes the rotary encoder 26 and the preset counter 38.
However, it is also possible to configure the rotation amount detection means by a combination other than these. For example, as a detector for detecting the amount of rotation of the injection screw 14, it is possible to use another detector such as a resolver instead of the rotary encoder 26, and as a counter,
Instead of preset counter 38, it is possible to use a conventional counter. Note that when a normal counter is used instead of the preset counter 38, the injection amount setting device 40 is generally connected to the controller 36, and the counting contents of the counter (number of input count pulses SP) and the injection amount setting device 40 are connected to the controller 36. The controller 36 compares the setting value set in . .

Furthermore, in the embodiment described above, the injection device was controlled by software by the controller 36 according to a predetermined program.
It is also possible to perform the control by hardware using an electric circuit. An example of the electric circuit is shown in the third section.
As shown in the figure.

That is, in the electric circuit of FIG.
When the mold clamping completion signal SK is input from the mold clamping device while the automatic changeover switch 42 is switched to the automatic state, the normally open contact 43 is closed and the relay 4
4 is energized, the normally closed contact 46 is opened, and the counting operation of the preset counter 38 is started. At the same time as the relay 44 is energized, the normally open contact 48 is closed, the solenoid 50 is energized, and the injection screw 14 (hydraulic motor 22) is rotationally driven. Then, the metering operation is started.

Next, while the injection screw 14 is being driven to rotate, when the preset value of the preset counter 38 matches the number of counting pulses SP input from the rotary encoder 26 to the preset counter 38, the normally closed contact 52 is opened. , the excitation of the solenoid 50 is released and the injection screw 1
4 is stopped. In other words, the weighing operation is ended. In addition, at this stage, the limit switch 54 in the figure is held in the open state, and the injection material guided to the front of the injection screw 14 during the above-mentioned metering operation is directly released into the product as in the previous embodiment. Sent into the cavity.

When the metering operation is completed, a predetermined injection operation similar to the above embodiment is performed, and the limit switch 54 is
is closed. When this injection operation is completed, the normally open contact 56 is closed and the relay 58 is energized.
0 is closed and the solenoid 50 is re-energized,
The rotational operation of the injection screw 14 is resumed. Then, when the injection screw 14 is rerotated to the position where the limit switch 54 is activated, the rotation of the injection screw 14 is stopped, and after a predetermined cooling period has elapsed, the mold opening operation is performed. , the normally open contacts 43, 56 are reset. As a result, the normally closed contact 4
6 is closed, and the preset counter 38 is reset (preset).

Even if such a circuit is adopted, the operation of the injection device can be controlled in the same manner as in the embodiment described above, and therefore the same effects as in the embodiment described above can be obtained.

In FIG. 3, 62 is a push button switch for starting the rotation of the injection screw 14 during manual operation, and 64 is a push button switch for stopping the rotation. Further, 66 and 68 are normally open contacts that are closed based on the excitation of the relay 70, respectively.

Further, in the above embodiment, the hydraulic motor 22 was employed as the rotational driving means for the injection screw 14, but an injection device that employs something other than the hydraulic motor 22, such as an electric motor, as the rotational driving means may also be used. It is possible to apply the present invention.

In addition, although not listed one by one, various modifications and changes may be made without departing from the spirit of the present invention.
Things that can be implemented with modifications, improvements, etc. are:
It goes without saying.

[Brief explanation of drawings]

FIG. 1 is a system diagram showing one embodiment of the present invention, FIG. 2 is a flow chart for explaining the operation when performing flow molding using the apparatus shown in FIG. 1, and FIG. The figure is a circuit diagram showing the main parts of another embodiment of the present invention. 10... Heating cylinder, 14... Injection screw, 22... Hydraulic motor, 26... Rotary encoder, 36... Controller, 38... Preset counter, 40... Injection amount setter (injection amount setting means), 50... Solenoid, 54... Limit switch.

Claims (1)

[Claims for Utility Model Registration] The injection material introduced into the heating cylinder is fluidized by the rotation of the injection screw, guided to the front of the injection screw, and injected into a predetermined product cavity through the nozzle of the heating cylinder. In the in-line screw type injection device, the injection amount setting means sets the amount of injection material guided forward of the injection screw as the rotation amount of the injection screw, and the rotation amount detects the rotation amount of the injection screw. a rotation amount detection means, and a rotation amount of the injection screw detected by the rotation amount detection means and a rotation amount of the injection screw set by the injection amount setting means are compared, and based on the fact that they match, the rotation amount of the injection screw is determined. An in-line screw type injection device characterized by being provided with metering operation stopping means for stopping the rotational operation of the injection screw.