KR20180012571A - Position detection type injection cylinder - Google Patents

Abstract

The present invention relates to a position detection type injection cylinder and, more specifically, relates to a position detection type injection cylinder which can accurately control an injection molding device by analyzing a position of a screw moving back and forth in an injection cylinder. According to the present invention, the position detection type injection cylinder comprises: an injection cylinder (110); a screw (120); a connection rod (130); an electric motor (140); an actuator (150); a measurement rod (160); a distance measurement unit (170); and a control unit (180).

Description

[0001] The present invention relates to a position detection type injection cylinder,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a position sensing injection cylinder apparatus, and more particularly to a position sensing injection cylinder apparatus capable of precisely controlling an injection molding apparatus by analyzing a position of a screw moving in a forward- will be.

2. Description of the Related Art Generally, an injection molding apparatus is made by injecting powdered or pelletized synthetic resin into an injection cylinder equipped with a heating device, melting the injection cylinder, and then injecting the material using a transfer screw installed in the injection cylinder.

Further, the injected molten material is pressed into a cavity inside the injection mold and cooled and cured to form a desired product, and it is widely used to mass-produce a product usually made of a synthetic resin.

1, a screw 12 is provided inside a barrel (injection cylinder) 11, and a screw 12 screwed to the ball nut 15 is screwed into a motor 12, (20) to move the screw (12) forward.

Therefore, the molten material filled in the barrel 11 is press-fitted into the injection mold by the screw 12 moving forward in the barrel 11. At this time, the amount of injection of the molten material to be injected into the injection mold, .

The injection amount or the injection time of the molten material is detected by using the rotation speed detected through the encoder 21 connected to the motor 20, and the injection molding process is controlled by feedback control repeatedly.

For example, in Korean Patent No. 10-1285371, when there are a plurality of cavities for simultaneously molding a plurality of products using one injection mold, the injection molding process is controlled so that the same amount of molten material is injected into each cavity .

That is, as shown in FIG. 2, the distances D1 to D3 from the injection port 33a of the injection mold to the cavities connected through the resin flow path 31 are different from each other, or the size ) (S1 to S3) are different, the respective pin valves are independently controlled.

The pin valve opens and closes the injection port of the cavity with the valve operation pin 39. The pin valve is operated by adjusting the direction of the pressure applied to the valve cylinder chamber through the fixed mounting plate 36 by the solenoid valves, 39).

Accordingly, by opening and closing the pin valves independently provided for each of the plurality of cavities at different timings, the pin valve for controlling the cavity located at a distance from the injection port 33a of the injection mold or the cavity of large size is opened first, So that an appropriate amount of molten material can be supplied.

However, as shown in Fig. 1, the rotational speed of the motor 20 is analyzed through the encoder 21, the control unit 22, and the like in order to inject a predetermined amount or the same amount of molten material into all the cavities, Speed information, it takes much time to process the data and it is impossible to provide precise timing information.

Therefore, it takes a long time to determine the opening / closing timing of the pin valve, so that the molding time of the product takes a long time. If the opening / closing timing of the pin valve is determined based only on the rotational speed of the motor 20 or the screw 12, Product failure occurs.

Korean Patent No. 10-0902480 Korean Patent No. 10-1285371

SUMMARY OF THE INVENTION The present invention is to solve the above-mentioned problems, and it is an object of the present invention to provide a position sensing injection cylinder apparatus capable of quickly and precisely controlling the injection molding apparatus by analyzing the positions of screws moving back and forth and rotating in the injection cylinder .

To this end, the position sensing injection cylinder apparatus according to the present invention comprises: an injection cylinder having a discharge port formed at a front side end thereof for injecting a molten material into a cavity inside the mold; A screw installed in the injection cylinder so as to be movable forward and backward and rotatable; A connection rod coupled to a rear end of the screw through a rear side opening of the injection cylinder; An electric motor coupled to the connection rod to rotate the screw through the connection rod; An actuator for moving the electric motor forward and backward; A measuring rod rotatably coupled to the connecting rod, the measuring rod moving in the back and forth direction together with the connecting rod when the actuator is operated; A distance measuring unit measuring a moving distance of the measuring rod; And a control unit for analyzing the measurement result of the distance measuring unit, analyzing the position of the screw in the injection cylinder, and controlling the molding apparatus according to the position information.

In this case, the measuring rod is preferably fixed to the bearing coupled to the connecting rod and rotatably coupled to the connecting rod.

In addition, the distance measuring unit may be a potentiometer disposed along the moving direction of the connection rod.

The control unit may control the control valve to control the injection of the molten material into the plurality of cavities formed in the mold according to the measurement result of the distance measuring unit.

Preferably, the control unit further detects at least one of the rotational speed, the rotational speed, and the rotational time of the electric motor to control the control valve.

As described above, the present invention detects the positions of the screws moving back and forth and rotating inside the injection cylinder to analyze the injection timing and injection amount of the molten material. Thus, the control loop time can be reduced to quickly control the injection molding apparatus while allowing precise control through accurate information based on the position.

1 is a view showing an injection cylinder apparatus according to the prior art.
2 is a view showing a pin valve of an injection mold according to the prior art.
3 is a first state view showing a position sensing injection cylinder apparatus according to the present invention.
4 is a second state diagram showing the position sensing injection cylinder apparatus according to the present invention.
5 is a partial cross-sectional view showing the state of the measuring rod assembly of the present invention.
6 is a schematic perspective view showing an injection mold applicable to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a position sensing injection cylinder apparatus according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

3 and 4, the position sensing injection cylinder apparatus according to the present invention includes an injection cylinder 110, a screw 120, a connecting rod 130, An electric motor 140, and an actuator 150. [

Particularly, the present invention has a structure in which the measuring rod 160, the distance measuring unit 170, and the control unit (not shown) are provided to detect the position of the screw 120 in the injection cylinder 110 when the molten material is injected, 180).

Accordingly, the present invention can quickly and precisely analyze the press-in pressure of the molten material depending on the starting point of injection of the molten material, the injection amount of the molten material, and the position of the screw 120 using the positional information analyzed by the above- Let's do it.

In addition, when a plurality of cavities corresponding to the product shape are formed in the molds M1 and M2, the control valve CV for controlling the molten material flowing into the respective cavities is controlled, Thereby enabling control over the entire period.

To this end, the injection cylinder 110 is provided with a discharge port at an end thereof on the front side (that is, toward the mold side) so as to inject the molten material into the cavity of the molds M1 and M2. On the other hand, an opening for connection of the connecting rod 130 is formed on the rear side.

The molds M1 and M2 to which the molten material is supplied from the injection cylinder 110 are formed of a first mold part M1 and a second mold part M2 each having a half cavity formed therein, The portion M2 moves forward and is tightly assembled to the first mold portion M1.

6) is formed in the first mold part M1 facing the injection cylinder 110. The injection port IN is connected to the cavity through a resin flow path as an example, IN), the discharge port of the above-described injection cylinder 110 is fitted.

This injection cylinder 110 is also called a 'barrel' and has a space in which a molten material is received. For example, a hopper 111 into which powder or pellet type solid raw material R 1 is injected Is installed. Additionally, the body of the injection cylinder 110 may be surrounded by a heating device 112.

Therefore, the solid raw material R1 injected into the injection cylinder 110 through the hopper 111 is melted due to crushing, friction and high pressure due to the rotation of the screw 120 to become the molten material R2, (R2) are press-fitted into the molds (M1, M2).

When the heating device 112 is additionally provided, it is also possible to supply power to the heating device 112 together with the rotation of the screw 120 to melt the solid raw material R1 with the heat generated, 111 may be supplied with the molten material R2 from the beginning.

The screw 120 is installed so as to be movable forward and backward and rotatable within the injection cylinder 110 as described above. That is, the screw 120 is a conventional part, and a plurality of blades are protruded from the outer circumferential surface of the rotary shaft, and the screw 120 is installed in the hollow portion of the injection cylinder 110.

The entire apparatus including the injection shaft, the electric motor 140, and the actuator 150 and the like are connected to the molds M1 and M2 by an LM guide or the like, And are moved together to come away from or close to the part.

3, when the injection molding process is started, the entire equipment including the injection cylinder 110 moves toward the molds M1 and M2, and the discharge port formed at the front end of the injection cylinder 110 moves to the molds M1 and M2 (Not shown).

On the other hand, although the illustration is omitted, after the injection molding is completed, the entire injection molding apparatus including the injection cylinder 110 moves backward by the LM guide or the like, is detached from the molds M1 and M2 and returns to the standby position.

The connecting rod 130 is coupled to the rear end of the screw 120 through the rear side opening of the injection cylinder 110 so that the screw 120 can be moved back and forth in the injection cylinder 110 .

The connection rod 130 is connected to the connector 121 provided at the rear end of the screw 120. The connector 121 is preferably connected to the injection cylinder 110 so as to seal the rear side opening of the injection cylinder 110. [ Sectional shape similar to that of the hollow portion of the honeycomb structure 110.

The front end of the connecting rod 130 is connected to the connector 121 of the screw 120 and the rear end of the connecting rod 130 is connected to the rotating shaft of the electric motor 140 to transmit power to the screw 120 While preventing the molten material R2 from leaking through the rear opening.

The rotation shaft of the electric motor 140 is coupled to the connection rod 130. At this time, the connection rod 130 is connected to the screw 120 as described above. Accordingly, when the electric motor 140 is operated, the screw 120 is rotated through the connecting rod 130.

The electric motor 140 is controlled by the control unit 180. For example, the control unit 180 transmits an instruction to start and stop the operation of the electric motor 140, and preferably controls the electric motor 140 in real time by feedback control and controls the rotational speed and the like.

As a method of monitoring the operation state of the electric motor 140, there is a method of A / D-converting the detection value of the encoder 21 connected to the rotation axis of the electric motor 140 and analyzing it Etc. may be used.

The actuator 150 moves the electric motor 140 forward and backward. The actuator 150 may be a geared motor coupled with a motor so long as it can move the electric motor 140 forward and backward.

In FIG. 3, an example of the actuator 150 is a hydraulic (or pneumatic) cylinder. Accordingly, when the cylinder rod of the hydraulic cylinder is connected to the electric motor 140, the electric motor 140 moves forward and backward in accordance with the pulling-in or pulling-out of the cylinder rod.

The connecting rod 130 and the screw 120 connected to the electric motor 140 are also moved forward and backward together with the electric motor 140. When the electric motor 140 is moved forward and backward with the electric motor 140, The position of the screw 120 is changed.

4, when the screw 120 is moved forward, the molten material R2 of the injection cylinder 110 is press-fitted into the molds M1 and M2. On the other hand, after the screw 120 is moved backward (not shown), the raw material R1 is injected through the hopper 111 to prepare the molten material R2 again.

On the other hand, the measuring rod 160 is rotatably coupled to the connecting rod 130 described above. At the same time, the actuator 150 is connected to the connecting rod 130 so as to move back and forth together with the connecting rod 130 in operation.

Therefore, even if the connecting rod 130 rotates by the electric motor 140, the measuring rod 160 maintains its position on the spot. On the other hand, when the connecting rod 130 is moved forward by the actuator 150, the measuring rod 160 also moves forward together with the connecting rod 130.

5, a bearing 161 is installed at an upper end of the measuring rod 160, and the bearing 161 is rotatably coupled to the connecting rod 130, As shown in Fig.

At this time, the ball of the bearing 161 is seated in the fitting groove 131 formed on the surface of the connecting rod 130 and moves together with the connecting rod 130 while supporting the rotation of the connecting rod 130. Of course, if necessary, the auxiliary groove 132 may be provided outside the front and rear of the fitting groove 131 so that the protrusion formed on the body of the bearing 161 may be fitted.

The distance measuring unit 170 measures the moving distance of the measuring rod 160 moving forward and backward together with the connecting rod 130 as described above. As the device for measuring the movement of the connection rod 130, various non-contact type sensors including an infrared distance sensor and the like can be used.

3, when the screw 120 is rotated by the electric motor 140 while the screw 120 is moved backward from the inside of the injection cylinder 110, the solid raw material R1 is melted and the melted material (R2) moves forward due to the pressure generated as the screw (120) blade rotates. At this time, the position of the screw 120 is measured as P1.

Then, as shown in FIG. 4, the actuator 150 is operated to press the molten material into the cavity inside the molds M1 and M2, and the screw 120 moves forward in the injection cylinder 110. FIG. At this time, the position of the screw 120 is measured as P2. Therefore, the moving distance is measured as L (L = P1 - P2).

3 and 4, a potentiometer may be used as the distance measuring unit 170, and the potentiometer is disposed long along the connecting rod 130 in the back and forth direction.

The potentiometer controls the amount or size of the electrical output signal through a mechanical position change and is connected to the contact portion 171 provided at the lower end of the measurement rod 160 in a contact or non-contact manner.

As is well known, the non-contact type is also called magnetoresistive type, and the resistance value changes depending on the strength of the magnetic field. And the magnetoresistive element is used as a resistor.

The control unit 180 controls the molding apparatus according to the measurement result of the distance measuring unit 170 to analyze the position information of the screw 120 sensed by the distance measuring unit 170 and process it into useful information that can be confirmed, Thereby controlling the molding apparatus.

For example, when the positional information of the screw 120 is used, it is possible to infer the pressurizing pressure of the molten material R2 depending on the starting point of injection of the molten material R2, the amount of the molten material R2 injected, and the position of the screw 120 It can be used for various controls.

The various controls of the above-described molding apparatus also include the forward and backward movement of the screw 120, the rotational speed and time of the screw 120, the operating distance and the operating speed of the actuator 150, Can be included in the object.

Particularly, the present invention controls the valve CV provided in the molds M1 and M2 using the above-described positional information. That is, the control unit 180 controls the control valve CV to control the injection of the molten material R2 into the plurality of cavities formed in the molds M1 and M2 according to the measurement result of the distance measuring unit 170 .

The controller 180 receives the digitally converted data from the A / D board 181 connected to the distance measuring unit 170 and processes the data provided from the A / D board 181, Is extracted.

Further, the relay 182 is controlled using the extracted position information, and the relay 182 controls the control valve CV. As the control valve CV, a solenoid valve may be used, and the timing and direction of supply of hydraulic pressure or pneumatic pressure (selection of opening or closing of the valve) to be used for opening and closing the pin valve is determined as described later.

As described with reference to FIG. 2, when there are a plurality of cavities for simultaneously molding a plurality of products with one injection mold, the control unit 180 of the present invention has the same amount of molten material (R2) The injection molding process is controlled so as to be injected.

At this time, the distances D1 to D3 from the injection port 33a of the injection mold to the cavities connected through the resin flow path 31 are different from each other, or the size (volume) S1 to S3 ) Is different, each pin valve is independently controlled.

At this time, the opening of the cavity is opened and closed by the valve operating pin 39 of the pin valve, and the direction of the pressure applied to the valve cylinder chamber through the fixed mounting plate 36 (the first chamber or the second chamber Are respectively controlled by the control valve CV to raise and lower the valve operating pin 39 at different timings.

Therefore, by opening the pin valves independently provided for each of the plurality of cavities at different timings, the pin valve for interrupting the cavity at a distance from the injection port 33a of the injection mold or the cavity having a large size is opened first, At the same time, to supply an appropriate amount of the molten material (R2).

6, the present invention may also be applied to the injection molding machine, for example, from the injection port IN of the molds M1 and M2 using the position information of the screw 120 detected by the distance measuring unit 170 When the distances L1, L2, and L3 to the pin valve PV of the intake valve 10 are different from each other (L1? L2? L3).

For example, when the molten material R2 arrives from the injection port IN at the center of the molds M1 and M2 to the cavities at different distances from the center of the molds M1 and M2 using the positional information, Open.

The opening of the pin valve PV is performed by using a pressure supply pipe (for example, a high pressure supply pipe) (not shown) provided so as to connect the inside of the molds M1 and M2 to the interior of the molds M1 and M2 And controls the upward and downward movement of the pin valve by adjusting the direction of the pressure supplied to the cylinder chamber.

Therefore, according to the present invention, it is possible to determine the injection amount of the molten material (R2) until the opening of the pin valve (PV) reaches the opening of the screw (120) Enabling precise control through precise information based on the position while quickly controlling the molding apparatus.

However, the control unit 180 of the present invention further detects at least one of the number of revolutions, the rotation speed and the rotation time of the electric motor 140 in controlling the opening and closing of the valve, and controls the control valve CV together with the position information And this is also the case when the actuator 150 is in operation as shown in Fig.

The specific embodiments of the present invention have been described above. It is to be understood, however, that the scope and spirit of the present invention is not limited to these specific embodiments, and that various modifications and changes may be made without departing from the spirit of the present invention. If you have, you will understand.

Therefore, it should be understood that the above-described embodiments are provided so that those skilled in the art can fully understand the scope of the present invention. Therefore, it should be understood that the embodiments are to be considered in all respects as illustrative and not restrictive, The invention is only defined by the scope of the claims.

110: injection cylinder
111: Hopper
112: Heating device
120: Screw
130: Connection Load
140: Electric motor
150: Actuator
160: Measurement load
161: Bearings
162:
170: Distance measuring part (potentiometer)
180:

Claims (5)

An injection cylinder 110 having a discharge port formed at a front end portion thereof to inject the molten material R2 into a cavity inside the molds M1 and M2;
A screw 120 installed to be movable forward and backward and rotatable within the injection cylinder 110;
A connection rod 130 coupled to a rear end of the screw 120 through a rear side opening of the injection cylinder 110;
An electric motor 140 coupled to the connection rod 130 to rotate the screw 120 through the connection rod 130;
An actuator 150 for moving the electric motor 140 forward and backward;
A measuring rod 160 rotatably coupled to the connecting rod 130 and moving in the back and forth direction together with the connecting rod 130 when the actuator 150 is operated;
A distance measuring unit 170 for measuring a moving distance of the measuring rod 160; And
And a control unit 180 analyzing the measurement result of the distance measuring unit 170 to analyze the position of the screw 120 in the injection cylinder 110 and controlling the molding apparatus according to the position information Wherein the position sensing cylinder is located at a predetermined position. The method according to claim 1,
The measuring rod (160)
Is fixed to a bearing (161) axially coupled to the connecting rod (130) and is rotatably coupled to the connecting rod (130). 3. The method of claim 2,
The distance measuring unit 170 measures a distance
Wherein the connection rod (130) is a potentiometer arranged to be long along the forward and backward movement directions of the connection rod (130). 4. The method according to any one of claims 1 to 3,
The control unit 180,
And controls the control valve CV for interrupting the introduction of the molten material R2 into a plurality of cavities formed in the molds M1 and M2 according to the measurement result of the distance measuring unit 170. [ Wherein the position sensing cylinder is mounted on the cylinder head. 5. The method of claim 4,
The control unit 180,
Wherein the controller controls the control valve CV by further detecting at least one of the rotation speed, the rotation speed and the rotation time of the electric motor 140. [

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