JP3336266B2 - Nozzle touch device of injection molding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nozzle touch device for an injection molding machine.

[0002]

2. Description of the Related Art Conventionally, an injection molding machine has an injection device and a mold device, and heats and melts a resin from an injection nozzle in a heating cylinder of the injection device. Then, after the injected resin is filled in the cavity space in the mold device, cooled and solidified, the mold device is opened to take out the molded product.

FIG. 2 is a conceptual diagram of a conventional injection molding machine, and FIG. 3 is a nozzle touch characteristic diagram of the conventional injection molding machine. In addition,
In FIG. 3, the horizontal axis indicates time t, and the vertical axis indicates firing power F and nozzle touch force f. In the figure, 10 is an injection device, 11 is a heating cylinder, 13 is the heating cylinder 11
Is an injection nozzle arranged at the front end (left end in FIG. 2). A screw (not shown) is provided in the heating cylinder 11 so as to be rotatable and movable back and forth so that the screw can be rotated and advanced and retracted.

For this purpose, a front plate 31 is arranged at a rear end (right end in FIG. 2) of the heating cylinder 11, and a rear plate 32 is arranged behind the front plate 31 (right side in FIG. 2) at a predetermined distance. Two guide rods 33 (two guide rods 3 in FIG. 2) are provided between the front plate 31 and the rear plate 32.
Only three are shown. ) Is erected. A pressure plate 34 is movably disposed between the front plate 31 and the rear plate 32 along a guide rod 33, and the rear end of the screw is rotatably supported by the pressure plate 34. . A ball nut 36 is fixed to the pressure plate 34, a ball screw shaft 37 is rotatably supported on the rear plate 32, and the ball nut 36 and the ball screw shaft 37 are screwed together. The ball screw shaft 37 is connected to an injection motor (not shown).

Accordingly, when the injection motor is driven to rotate the ball screw shaft 37, the ball nut 36
Is moved forward and backward, and the screw is moved forward and backward together with the ball nut 36. The screw has a screw head at the front end. A spiral flight is formed on the surface of the metering portion of the screw, and a groove is formed along the flight.

In the injection apparatus 10 having the above-described configuration, when the screw is rotated in the forward direction and moved backward (moved to the right in FIG. 2) by driving a measuring motor (not shown) at the time of the measuring step, it is not shown. The pellet-shaped resin in the hopper enters the heating cylinder 11, is advanced in the groove (moves to the left in FIG. 2), is heated and melted by a heater (not shown), and is heated in front of the screw head. It is stored.

When the injection motor is driven to advance the screw during the injection process, the resin stored in front of the screw head is injected from the injection nozzle 13 and is not shown in the mold apparatus 14. The cavity is filled. In addition, the mold apparatus 14 includes a fixed mold 1
The mold is closed, clamped and opened by moving the movable mold 16 forward and backward by a mold clamping device (not shown) and moving the movable mold 16 toward and away from the fixed mold 15.

Subsequently, when the filling of the cavity space with the resin is completed, cooling water flows through a cooling passage (not shown) formed in the mold apparatus 14 to cool the resin. When the resin solidifies, the mold is opened, and the molded product is taken out. By the way, if the injection nozzle 13 and the fixed mold 15 do not contact with a predetermined pressing force, that is, the nozzle touch force f while the cavity space is filled with the resin, the injection nozzle 13 and the fixed mold 15 are not contacted. The resin leaks from between.

Therefore, before the injection is started, the injection device 10 is advanced by the nozzle touch device, and the injection nozzle 13 is moved to the fixed mold 15 by a predetermined nozzle touch force f.
The nozzle is touched by pressing with. For this purpose, a guide 41 is provided over a predetermined distance on the frame 21 of the injection molding machine.
The injection device 10 is slidably mounted on 1. A slide block 43 is attached to a lower end of the front plate 31, and a slide block 44 is attached to a lower end of the rear plate 32.

A motor 25 with a brake is fixed to the frame 21, and an output shaft 25 a of the motor 25 and a ball screw shaft 23 are connected via a coupling 22. A spring cylinder 51 is fixed to the rear end surface of the slide block 43, and a piston 53 is disposed in the spring cylinder 51 so as to be able to advance and retreat. The piston 53 and a ball nut (not shown) are fixed. The ball screw shaft 23 is screwed.
A spring 54 is provided in a chamber in the spring cylinder 51 in front of the piston 53, and urges the piston 53 in the spring cylinder 51 rearward.

A sensor 28 is provided so as to face the piston 53, and the amount of deflection x is detected by detecting the position of the deflection (deflection) of the spring 54 by the sensor 28. In this case, by driving the motor 25 to rotate the ball screw shaft 23, the ball nut and the piston 53 are advanced from the retreat limit position, and the injection device 10 is advanced. Then, the injection device 10 reaches the nozzle touch position, and the injection nozzle 13 contacts the fixed mold 15. Subsequently, in a state where the injection nozzle 13 is in contact with the fixed mold 15, when the motor 25 is further driven, the piston 53 is advanced in the spring cylinder 51 against the urging force of the spring 54,
The spring 54 bends by the distance the piston 53 has advanced, and at this time, the injection nozzle 13 presses the fixed mold 15 by an amount corresponding to the amount of deflection x of the spring 54. Therefore, the nozzle touch force f can be detected by detecting the bending position of the spring 54. When the deflection amount x reaches the set value x1 and the nozzle touch force f1 equal to the target nozzle touch force f1 is generated, the motor 25 is stopped.

When the nozzle touch is performed in this manner, the injection motor is driven, the ball screw shaft 37 is rotated, the ball nut 36 and the pressure plate 34 are advanced, and the screw is advanced. Then, the resin in the heating cylinder 11 is injected from the injection nozzle 13 to fill the cavity space.
At this time, the force of the screw to move forward, that is, the ejection force F increases with the injection of the resin, and when the resin is filled in the cavity space, the peak value F
Reach one. Then, when the resin is filled in the cavity space and the injection process is completed, the injection motor is stopped. As a result, the firing power F decreases.

[0013]

However, in the nozzle touch device of the conventional injection molding machine, as the injection power F increases, the pressure of the resin in the heating cylinder 11 increases, and the injection nozzle 13 The resin easily leaks from a gap (gap) between the resin and the fixed mold 15. Therefore, it is necessary to increase the target nozzle touch force f1 by that much. However, if the target nozzle touch force f1 is set to be large, a large pressure is applied to the fixed die 15, so that the life of the die device 14 is reduced. Becomes shorter.

Further, the contact between the injection nozzle 13 and the fixed mold 15 becomes tighter as the target nozzle touch force f1 increases, so that a large amount of heat of the injection nozzle 13 is transmitted to the mold apparatus 14, The temperature of the resin in the injection nozzle 13 decreases accordingly. The present invention solves the problems of the conventional nozzle touch device of an injection molding machine, can reduce a target nozzle touch force, can prolong the life of a mold device, An object of the present invention is to provide a nozzle touch device of an injection molding machine that can increase the temperature of a resin.

[0015]

For this purpose, a nozzle touch device for an injection molding machine according to the present invention comprises a frame,
An injection device movably disposed with respect to the frame, provided with an injection nozzle, a motor for moving the injection device forward and backward, and converting a rotational force generated by the motor into a thrust, and converting the thrust into a thrust. Conversion means for transmitting to the injection device;
There is provided storage means for storing the nozzle touch force, which is provided between the conversion means and the injection device.

[0016] The injection device includes a displacement member that is displaced in accordance with the firing power, and the storage means is attached to the displacement member. In the nozzle touch device of another injection molding machine of the present invention, the accumulating means further includes an urging means for generating an urging force for changing the nozzle touch force.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a conceptual diagram of an injection molding machine according to an embodiment of the present invention, FIG. 4 is an operation explanatory diagram of the injection molding machine according to the embodiment of the present invention, and FIG. 5 is a nozzle of the injection molding machine according to the embodiment of the present invention. FIG. 4 is a touch characteristic diagram. In FIG. 5, time t is plotted on the horizontal axis,
The vertical axis represents the firing power F and the nozzle touch force f.

In FIG. 1, reference numeral 10 denotes an injection device, 11 denotes a heating cylinder, and 13 denotes an injection nozzle provided at a front end (left end in FIG. 1) of the heating cylinder 11. A screw (not shown) is provided in the heating cylinder 11 so as to be rotatable and movable back and forth so that the screw can be rotated and advanced and retracted.

For this purpose, a front plate 31 is provided at a rear end (right end in FIG. 1) of the heating cylinder 11 and a rear plate as a displacement member is disposed at a predetermined distance behind (frontward in FIG. 1) the front plate 31. A plate 32 is provided, and the front plate 31 and the rear plate 32 are provided.
Between them, four guide rods 33 (only two guide rods 33 are shown in FIG. 1) are installed.
A pressure plate 34 is movably disposed between the front plate 31 and the rear plate 32 along a guide rod 33.
4, the rear end of the screw is rotatably supported. Then, a ball nut 36 is attached to the pressure plate 34.
Is fixed, a ball screw shaft 37 is rotatably supported on the rear plate 32, the ball nut 36 and the ball screw shaft 37 are screwed together, and the ball screw shaft 37 is connected to an injection motor (not shown). You.

Therefore, when the injection motor is driven to rotate the ball screw shaft 37, the ball nut 36 is rotated.
Is moved forward and backward, and the screw is moved forward and backward together with the ball nut 36. In addition, the ball nut 36 and the ball screw shaft 37 convert the rotational force into a thrust.
Is formed. In the present embodiment, the ball nut 36 is fixed and the ball screw shaft 37 is rotated. However, the ball nut can be rotated by an injection motor to fix the ball screw shaft. .

The screw has a screw head at the front end. A spiral flight is formed on the surface of the metering portion of the screw, and a groove is formed along the flight. The injection device 10 includes a heating cylinder 11, an injection nozzle 13, and a front plate 3.
1. Rear plate 32, guide rod 33, pressure plate 34, ball nut 36, and ball screw shaft 37
Composed of

In the injection device 10 having the above-described configuration, when the screw is rotated in the forward direction and moved backward (moved to the right in FIG. 1) by driving a not-illustrated measuring motor during the measuring process, it is not shown. The pellet-shaped resin in the hopper enters the heating cylinder 11, is advanced in the groove (moves to the left in FIG. 1), is heated and melted by a heater (not shown), and is heated in front of the screw head. It is stored.

When the screw is advanced by driving the injection motor during the injection step, the resin stored in front of the screw head is injected from the injection nozzle 13 and is not shown in the mold apparatus 14. The cavity is filled. In addition, the mold apparatus 14 includes a fixed mold 1
The mold is closed, clamped and opened by moving the movable mold 16 forward and backward by a mold clamping device (not shown) and moving the movable mold 16 toward and away from the fixed mold 15.

Subsequently, when the filling of the cavity space with the resin is completed, cooling water is flowed through a cooling flow path (not shown) formed in the mold apparatus 14 to cool the resin. When the resin solidifies, the mold is opened, and the molded product is taken out. By the way, if the injection nozzle 13 and the fixed mold 15 do not contact with a predetermined nozzle touch force while the cavity space is filled with the resin, the injection nozzle 1
The resin leaks from between the mold 3 and the fixed mold 15.

Therefore, before the injection is started, the injection device 10 is advanced by the nozzle touch device, and the injection nozzle 13 is pressed against the fixed mold 15 with a predetermined nozzle touch force to perform the nozzle touch. It has become. For this purpose, a guide 41 is provided on the frame 21 of the injection molding machine over a predetermined distance.
The injection device 10 is slidably disposed thereon. In addition,
A slide block 4 is provided at the lower end of the front plate 31.
A slide block 44 is attached to the lower end of the rear plate 32, and each of the slide blocks 3 is placed on the guide 41.

A motor 25 with a brake is fixed to the frame 21, and an output shaft 25 a of the motor 25 and a ball screw shaft 23 are connected via a coupling 22. A spring cylinder 61 is fixed to the rear end surface of the slide block 44, and a piston 63 is disposed in the spring cylinder 61 so as to be able to advance and retreat. The piston 63 and a ball nut (not shown) are fixed. The ball screw shaft 23 is screwed.
The ball nut and the ball screw shaft 23 constitute a second converting means for converting a rotational force into a thrust. Further, a spring 6 as an urging means is provided in a chamber in front of the piston 63 in the spring cylinder 61.
In the spring cylinder 61, the piston 63 is turned rearward, and the slide block 4
4 is urged forward with a predetermined urging force. The spring cylinder 61, the piston 63, and the spring 64 constitute an accumulation unit. In the force transmission system, the spring cylinder 61, the piston 63, and the spring 64 are connected to the ball screw shaft 23, the ball nut, and the injection device 10. A nozzle touch force f corresponding to the urging force is stored therebetween.

A sensor 28 is provided so as to face the piston 63. The sensor 28 detects a bending position x of the spring 64 by detecting a bending position of the spring 64. In this case, by driving the motor 25 to rotate the ball screw shaft 23, the ball nut and the piston 63 are advanced from the retreat limit position, and the injection device 1
0 is advanced. Here, the urging force of the spring 64 is set to be larger than the frictional force generated between the slide blocks 43 and 44 and the guide 41. Therefore,
The spring 64 does not bend until the injection nozzle 13 contacts the fixed mold 15.

Then, the injection device 10 reaches the nozzle touch position and the injection nozzle 13 is brought into contact with the fixed mold 15, and in this state, when the motor 25 is further driven,
The piston 63 is advanced in the spring cylinder 61 against the urging force of the spring 64, and the spring 64 is bent by the distance that the piston 63 has advanced.
Is pressed by the fixed mold 15. Therefore, the nozzle touch force f can be detected by detecting the bending position of the spring 64. And the deflection amount x
Reaches the set value x0 and the nozzle touch force f equal to the target nozzle touch force f3 is generated, the motor 25
Is stopped.

When the nozzle touch is performed in this manner, the injection motor is driven, the ball screw shaft 37 is rotated, the ball nut 36 and the pressure plate 34 are advanced, and the screw is advanced. Then, the resin in the heating cylinder 11 is injected from the injection nozzle 13 to fill the cavity space.
At this time, the emission power F increases as the resin is injected, and reaches a peak value F2 when the resin is filled in the cavity space. When the resin is filled in the cavity space and the injection process is completed, the injection motor is stopped. As a result, the firing power F decreases.

In this case, as the injection power F increases, the pressure of the resin in the heating cylinder 11 increases, and the resin easily leaks from the gap between the injection nozzle 13 and the fixed mold 15. However, since the spring cylinder 61 is mounted on the slide block 44, the nozzle touch force f can be reduced when the firing force F is small, and the nozzle touch force f can be increased when the firing force F is large. When the output F reaches the peak value F2, the nozzle touch force f can be set to the peak value f2.

That is, the injection power F is generated by injecting the resin in the heating cylinder 11 from the injection nozzle 13, and works to extend the guide rod 33 outside the heating cylinder 11. The front end of the guide rod 33 is fixed to the front plate 31, and the front plate 31 is pressed against the fixed mold 15 via the heating cylinder 11 and the injection nozzle 13 and does not move. Accordingly, the rear plate 32 is displaced and moved rearward with the extension of the guide rod 33, and the displacement of the rear plate 32 corresponds to the radiation output F.

Here, when the amount of deflection of the spring 64 when the ejection force F is not generated is the set value x0, the amount of extension of the guide rod 33 when the ejection force F is generated, ie, the rear plate When the displacement of the spring 32 is Δx, the actual deflection X of the spring 64 is X = x0 + Δx. Therefore, the nozzle touch force f can be increased by an amount corresponding to the increase in the firing output F. That is, since a sufficient nozzle touch force f can be generated in accordance with the magnitude of the firing power F, the target nozzle touch force f3 can be reduced accordingly. as a result,
Since unnecessarily large pressure is not applied to the fixed mold 15, the mold apparatus 14 is not damaged, and the life of the mold apparatus 14 can be extended.

Further, it is not necessary to make the contact between the injection nozzle 13 and the fixed mold 15 tighter as much as the target nozzle touch force f3 becomes smaller. Therefore, a large amount of heat of the injection nozzle 13 is not transmitted to the mold apparatus 14, so that the temperature of the resin in the injection nozzle 13 can be increased. It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and they are not excluded from the scope of the present invention.

[0034]

As described above in detail, according to the present invention, in a nozzle touch device of an injection molding machine, a frame and an injection nozzle provided movably with respect to the frame and having an injection nozzle. Device, a motor for moving the injection device forward and backward, conversion means for converting the rotational force generated by the motor into thrust, and transmitting the thrust to the injection device, the conversion means and the injection device, Arranged between
Storage means for storing the nozzle touch force.

The injection device includes a displacement member that is displaced in accordance with the firing power, and the storage means is attached to the displacement member. In this case, since the displacement member is displaced in accordance with the generation of the firing force, the accumulation means can accumulate the nozzle touch force corresponding to the displacement amount of the displacement member.
Therefore, a sufficient nozzle touch force can be generated in accordance with the magnitude of the firing power, and the target nozzle touch force can be reduced accordingly. As a result, no large pressure is applied to the mold device,
The mold device is not damaged, and the life of the mold device can be extended.

Further, it is not necessary to make the contact between the injection nozzle and the mold apparatus close to each other as much as the target nozzle touch force is reduced. Therefore, since a large amount of heat of the injection nozzle is not transmitted to the mold device, the temperature of the resin in the injection nozzle can be increased.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an injection molding machine according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a conventional injection molding machine.

FIG. 3 is a nozzle touch characteristic diagram of a conventional injection molding machine.

FIG. 4 is an operation explanatory view of the injection molding machine according to the embodiment of the present invention.

FIG. 5 is a nozzle touch characteristic diagram of the injection molding machine according to the embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 10 Injection device 13 Injection nozzle 21 Frame 25 Motor 32 Rear plate 36 Ball nut 37 Ball screw shaft 61 Spring cylinder 63 Piston 64 Spring F Firing power f Nozzle touch force

Claims (2)

(57) [Claims] 1. An (a) frame, (b) an injection device movably disposed with respect to the frame and provided with an injection nozzle, (c) a motor for moving the injection device forward and backward,
(D) converting means for converting a rotational force generated by the motor into a thrust and transmitting the thrust to the injection device;
(E) a storage device that is provided between the conversion device and the injection device and stores a nozzle touch force;
(F) The injection device includes a displacement member that is displaced in accordance with the firing power, and (g) the accumulation unit is attached to the displacement member. 2. The nozzle touch device of an injection molding machine according to claim 1, wherein said accumulating means includes an urging means for generating an urging force for changing a nozzle touch force.