JP3083729B2 - Injection device for electric 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 an injection device for an electric injection molding machine.

[0002]

2. Description of the Related Art As an injection device of a conventional electric injection molding machine, there is one disclosed in Japanese Patent Application Laid-Open No. 3-132322. The injection device of the electric injection molding machine shown here includes a movable injection unit main body having a nozzle, a ball screw rotatably supported by a stationary portion, and an electric motor rotatably driving the ball screw. A ball nut that meshes with a ball screw to form a ball screw mechanism, and a nozzle pressing force (also referred to as a nozzle touch force) in a forward direction of the ball nut and the injection unit main body is transmitted via a spring, and is transmitted in the opposite direction. The nozzle retreating force is directly connected to the connecting mechanism, the pneumatic cylinder connected to the injection unit body and the fixed plate, and the control for controlling the force generated by the pneumatic cylinder to press the injection unit against the mold. Device. Thereby, the nozzle touch force for pressing the nozzle against the mold is switched from a state generated by the spring to a state generated by the pneumatic cylinder. That is, a state in which the injection unit main body is moved forward and backward by the pneumatic cylinder and a state in which a spring generates a nozzle touch force for pressing the nozzle against the mold at the forward limit are switched.

[0003]

However, in the injection device of the conventional electric injection molding machine as described above, when the nozzle touch force is switched from a spring-based one to a pneumatic one, the nozzle touch force is reduced. The nozzle temporarily retracts due to the response delay due to compressibility and the reaction force of the spring, or the actual nozzle pressing force becomes smaller than the set value due to the frictional force of the power transmission mechanism. There is a problem that resin leakage may occur. That is, for the latter, when the nozzle touch force is generated by the pneumatic cylinder, the injection unit is connected to an electric motor with a speed reducer via a spring and a ball screw mechanism. Although the set value is increased by the amount, the actual nozzle pressing force becomes smaller than the set value as described above due to the instability of the frictional force, which may cause resin leakage. In order to increase the certainty of preventing resin leakage, it is conceivable that the nozzle touch force is set to a larger value.
Since the contact portion between the nozzle and the mold is easily damaged due to the strong nozzle touch force, and maintenance is troublesome, there is a limit to increasing the nozzle touch force. An object of the present invention is to solve such a problem.

[0004]

The present invention solves the above-mentioned problems by providing a connection switching mechanism for switching between connection and disconnection between an injection unit and a ball screw mechanism, instead of a spring. That is, the injection device of the electric injection molding machine according to the first aspect of the present invention comprises an injection unit main body (10) movable toward and away from the mold (54), and a linear motion screw member (32). ) And a rotary screw member (34).
34), the electric motor (40) connected to the rotary motion screw member (34) of the ball screw mechanism (32, 34), and the nozzle touch state where the injection unit main body (10) is in contact with the mold (54). A pressurizing pneumatic cylinder (22) for applying a nozzle touch force to the injection unit body (10), a pressurizing control electromagnetic switching valve (48) for switching the flow of air to the pressurizing pneumatic cylinder (22), and an electric motor (40) And a controller (4) for controlling the electromagnetic switching valve (48) for pressing control.
6), wherein the linear motion screw member (32) is connected to the injection unit main body (10), and the injection unit main body (10) and the linear motion screw member (32) are connected. ) Is provided with a connection switching mechanism (35) that switches between the connected state and the disconnected state. Further, claim 2 of the present invention
In the injection device of the electric injection molding machine described above, the controller (46) is configured to connect the injection unit main body (10) and the linear motion screw member (32) when the injection unit main body (10) moves forward and backward. When the pressing pneumatic cylinder (22) exerts the nozzle touch force after the nozzle touch, while the injection unit body (10)
The connection switching mechanism (35) is controlled so that the and the linear motion screw member (32) are not connected. Further, in the injection device of the electric injection molding machine according to the third aspect of the present invention, the connection switching mechanism (35) includes:
It has a cylinder body (36a), a piston rod (36b) and a piston (36c) integral therewith, and one of the cylinder body (36a) and the piston rod (36b) is connected to the injection unit body (10). And the other is connected to the linear motion screw member (3
Pneumatic cylinder for switching connection (36) connected to 2)
And a connection switching control electromagnetic switching valve (42) for switching the flow of air to the connection switching pneumatic cylinder (36). The controller (46) controls the connection switching mechanism (35) with respect to the connection switching mechanism (35). The control is performed by controlling the electromagnetic switching valve (42) for connection switching control. In addition, the code | symbol in a parenthesis shows the corresponding member of an Example.

[0005]

When the injection unit main body is moved, the connection switching mechanism is connected and the electric motor is driven to move the injection unit main body back and forth through the ball screw mechanism. After the nozzle touches when the nozzle contacts the mold during forward movement, the connection switching mechanism is switched to the non-connection state, the electric motor is stopped, and the pressing pneumatic cylinder is operated. Thus, the ball screw mechanism and the injection unit main body are not connected to each other, and the nozzle touch force is directly applied to the injection unit main body from the pressing pneumatic cylinder. Since the nozzle touch force can be set to the minimum necessary without considering the frictional force of the power transmission mechanism, the life of the contact part between the nozzle and the mold can be extended, and the nozzle can be reliably touched. Can be.

[0006]

FIG. 1 shows an embodiment of the present invention. A rail 14 is provided on a bed 16 fixed to a stationary part, and a slide plate 12 is provided on the rail 14 so as to be movable. The injection unit main body 10 and the bracket 24 are respectively attached to the slide plate 12. The injection unit main body 10 has a heating cylinder 18 having a screw (not shown) therein and a nozzle 20 provided at a left end portion of the heating cylinder 18 in the drawing. A ball screw (rotational movement screw member) 34 penetrates the center of the bracket 24, and a rod 30 of a connection switching mechanism 35, which will be described later, penetrates upper and lower ends in FIG. 2. The piston rod 36b is connected to the middle part. In FIG. 1, a fixed platen 52 that constitutes a mold clamping device 51 is provided so as to face the nozzle 20. In addition, as the mold clamping device 51, in addition to the above-described fixed plate 52, a mold 54 attached to the fixed plate 52, and a surface of the fixed plate 52 opposite to the nozzle 20 facing surface are provided to face each other. It has a movable plate (not shown), a movable mold attached to the movable plate, and a mold clamping mechanism for driving the movable plate and the movable mold in the mold opening and closing direction in an integrated state. Between the injection unit main body 10 and the fixed platen 52, two pressurized pneumatic cylinders
2 are arranged. That is, the cylinder body 22a of the pressing pneumatic cylinder 22 is fixed to the injection unit body 10, and the piston rod 22b integral with the piston 22c is connected to the fixed plate 52 via the joint 56. The cylinder body 22a is partitioned into a pressing pressure chamber A on the left side in the figure and a chamber B on the right side in the figure by the piston 22c. The pressurizing pressure chamber A of the pressurizing pneumatic cylinder 22 is connected to the pressurizing control electromagnetic switching valve 48 via a pipe 68.
A port is connected. Electromagnetic switching valve 4 for pressing control
The P port 8 is connected to the second air pressure source 50 via a pipe 70. The chamber B of the pneumatic cylinder 22 for pressing and the R1 port of the electromagnetic switching valve 48 for controlling pressing are each opened to the atmospheric pressure. The switching position of the pressing control electromagnetic switching valve 48 is controlled by a controller 46 described later via a signal line 62. The pressurizing pneumatic cylinder 22 is, as described later, the injection unit main body 1.
The nozzle 2 is not activated while the motor 0 is moved by the electric motor 40 via the ball screw mechanism including the ball screw 34 and the ball nut (linear motion screw member) 32.
The nozzle unit 20 is driven after the injection unit main body 10 is stopped by contacting the fixed side mold 54 with 0, and the nozzle touch force can be applied to the nozzle 20.

(Connection switching mechanism 35) As shown in FIG.
Two plates 26 and 28 are arranged on both left and right sides of the drawing with a bracket 24 (integral with the injection unit main body 10 and the slide plate 12) interposed therebetween. Both plates 26
And 28 are a plurality of rods 3 passing through the bracket 24.
0 are integrally connected. A ball nut 32 is fixed to the first plate 26 on the left side in the drawing. A ball screw 34 is screwed into the ball nut 32. The ball screw 34 is connected to a shaft of the electric motor 40 via a coupling 38 (see FIG. 1). Electric motor 40
Is attached to the bed 16. The cylinder main body 36a of the connection switching pneumatic cylinder 36 is attached to the upper and lower two places in the figure on the second plate 28 on the right side in the figure. Piston rod 3 of connection switching pneumatic cylinder 36
6b has one end connected to the piston 36c and the other end penetrating the second plate 28 and connected to the bracket 24. The cylinder body 36a is connected to the connection pressure chamber C on the right side in the drawing by the piston 36c,
It is partitioned into a room D on the left side in the figure. Cylinder body 36
A position sensor 37 is attached to a. The position sensor 37 can output a signal by detecting that the piston 36c is located at a position indicated by a broken line in FIG. The connection pressure chamber C of the connection switching pneumatic cylinder 36 is connected to the B port of the connection switching control electromagnetic switching valve 42 via a pipe 64 as shown in FIG. The P port of the connection switching control electromagnetic switching valve 42 is connected to the first air pressure source 44 via a pipe 66. The A and R1 ports of the connection switching control electromagnetic switching valve 42 are blocked, and the R2 port is open to atmospheric pressure. In the case of this embodiment, the connection switching mechanism 35 includes a connection switching pneumatic cylinder 36, a connection switching control electromagnetic switching valve 42, and plates 26 and 28. A controller 46 is provided on a control panel of the injection molding machine. The controller 46 is
The switching position of the connection switching control electromagnetic switching valve 42 is controlled via a signal line 60 and the motor 4 is controlled via a signal line 58.
Although the rotation of 0 is controlled, the switching position of the pressing control electromagnetic switching valve 48 is also controlled via the signal line 62 based on the signal from the position sensor 37 as described above.

Next, the operation of this embodiment will be described. The metering process is performed in a state where the injection unit main body 10 is located at the retracted position as shown in FIG. During the weighing process, the connection switching control electromagnetic switching valve 42 is switched to the illustrated symbol position by a command signal from the controller 46, and the connection switching pneumatic cylinder 36 is connected to the connection pressure chamber C by the first pressure. Since air pressure is supplied from the first air source 44 through the pipe 66, the connection switching control electromagnetic switching valve 42, and the pipe 64, the bracket 24 is moved to the first position as shown by a solid line in FIG.
It is located at the connection position pressed against the plate 26. Further, since the pressing control electromagnetic switching valve 48 is switched to the illustrated symbol position by a command signal from the controller 46, the pressing pneumatic cylinder 22 opens the pressing pressure chamber A to the atmospheric pressure. Have been. When a predetermined amount of the molten resin is measured in the heating cylinder 18, the controller 46
, The electric motor 40 is driven, and the ball screw 34 is rotated via the coupling 38.
Therefore, the ball nut 32, the first plate 26, the second plate 28, the connection switching pneumatic cylinder 36, the bracket 24, the slide plate 12, and the injection unit main body 10 are advanced in an integrated state. When the nozzle 20 comes into contact with the mold 54 and the piston 36c moves from the position indicated by the solid line in FIG. 2 to a position separated to the right by the distance x indicated by the broken line in FIG. 2, a signal is sent from the position sensor 37 to the controller 46. Is output. Based on a signal from the controller 46, the connection switching control electromagnetic switching valve 42 is switched to the symbol position on the left side in the figure. As a result, the connection pressure chamber C of the connection switching pneumatic cylinder 36 is opened to the atmosphere, and the connection switching mechanism 35 is brought into a non-connection state. At the same time, the pressing control electromagnetic switching valve 48 is switched to the symbol position on the left side in the figure. As a result, the pressing pneumatic cylinder 22 has its second pressure source 5 in its pressing pressure chamber A.
0 to the pipe 70, the push-control electromagnetic switching valve 48 and the pipe 6
Air pressure flows through 8 and presses the nozzle 20 against the mold 54. At this time, the injection unit body 10
Is not connected to the motor 40 side, and is not affected by these frictional forces.
The nozzle touch force as set can be applied directly to the nozzle 20 by the pressing air pressure cylinder 22.
Further, when switching from the forward operation by the electric motor 40 to the nozzle touch force generation operation, a force for retreating the nozzle 20 does not act. In this state, the injection process is performed, and the molten resin is injected from the nozzle 20 into the mold 54. Therefore, there is no possibility that the resin leaks from the nozzle 20.

In the description of the above embodiment, the ball screw 34 is rotated so that the ball nut 3 moves linearly.
2 is connected / disconnected to the injection unit main body 10 side, but the present invention can also be applied to a configuration in which a ball nut is rotated and a ball screw moves linearly. In this case, the ball screw may be connected / disconnected to the injection unit main body 10 side.
Further, in the description of the above embodiment, the bracket 24 is attached to the slide plate 12, but the bracket 24 can be attached to the injection unit main body 10 side. Further, in the description of the above embodiment, the two air pressure sources, the first air pressure source 44 and the second air pressure source 50, are used as the air pressure sources. Can also.

[0010]

As described above, according to the present invention, when switching from the forward movement of the injection unit main body to the nozzle touch force generation operation, a force for retracting the nozzle does not act. There is no risk of resin leakage from the nozzle. In addition, the injection unit main body receives the nozzle touch force in a state where it is not connected to the motor side, so that the injection unit main body is not affected by the frictional force of the power transmission mechanism on the motor side. Since it can act on the nozzle, stable nozzle touch can be performed, and there is no occurrence of resin leakage from the nozzle due to insufficient nozzle touch force. When setting the nozzle touch force, it is not necessary to consider the effect of the frictional force of the power transmission mechanism.
In addition, the setting change operation of the nozzle touch force can be easily performed.

[Brief description of the drawings]

FIG. 1 is a view showing an injection device according to an embodiment of the present invention together with a part of a mold clamping device.

FIG. 2 is an enlarged view showing a connection switching mechanism portion of the injection device.

[Explanation of symbols]

 Reference Signs List 10 Injection unit main body 12 Slide plate 14 Rail 16 Bed 18 Heating cylinder 20 Nozzle 22 Pneumatic cylinder for pressing 24 Bracket 26 First plate 28 Second plate 30 Rod 32 Ball nut (linear motion screw member) 34 Ball screw (rotary motion screw member) 35) Connection switching mechanism 36 Connection switching pneumatic cylinder 36a Cylinder main body 36b Piston rod 36c Piston 40 Motor 42 Connection switching control electromagnetic switching valve 44 First air pressure source 46 Controller 48 Pushing control electromagnetic switching valve 50 Second air pressure source 54 Die A Pressure chamber for pressing C Pressure chamber for connection

Continuation of front page (56) References JP-A-4-255319 (JP, A) JP-A-2-214631 (JP, A) JP-A-6-79759 (JP, A) JP-A-8-118425 (JP JP-A-8-318551 (JP, A) JP-A-3-132322 (JP, A) JP-A-5-92447 (JP, A) Actually open 7-2030 (JP, U) Actually open 7-94416 (JP, U) Japanese Utility Model 3-4016 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B29C 45/00-45/84

Claims (3)

(57) [Claims] An injection unit main body (10) movable toward and away from a mold (54).
And a linear motion screw member (32) and a rotary motion screw member (34).
And a rotary screw member (3) of the ball screw mechanism (32, 34).
And a pneumatic cylinder (22) for applying a nozzle touch force to the injection unit main body (10) in a nozzle touch state where the injection unit main body (10) is in contact with the mold (54). )
And a solenoid control valve (48) for controlling the pressing of the air to the pneumatic cylinder (22) for pressing, and a controller (46) for controlling the motor (40) and the solenoid switching valve (48) for the pressing control. The linear motion screw member (32) is provided with an injection unit main body (10).
A connection switching mechanism (35) for switching the injection unit body (10) and the linear motion screw member (32) to one of a connected state and a non-connected state. ) Is provided, The injection device of the electric injection molding machine characterized by the above-mentioned. 2. The controller (46) connects the injection unit main body (10) and the linear motion screw member (32) when the injection unit main body (10) moves forward and backward, When the pressing pneumatic cylinder (22) exerts a nozzle touch force after the nozzle touch, the connection switching mechanism (35) is set so that the injection unit main body (10) and the linear motion screw member (32) are disconnected. 2. The injection device for an electric injection molding machine according to claim 1, wherein 3. The connection switching mechanism (35) has a cylinder body (36a), a piston rod (36b) and a piston (36c) integral therewith, and includes a cylinder body (36a) and a piston rod (36b). ) Is connected to the injection unit body (10), and the other is connected to the linear motion screw member (3).
Pneumatic cylinder for switching connection (36) connected to 2)
And a connection switching control electromagnetic switching valve (42) for switching the flow of air to the connection switching pneumatic cylinder (36). The controller (46) for the connection switching mechanism (35) The injection device of an electric injection molding machine according to claim 1 or 2, wherein the control is performed by controlling a connection switching control electromagnetic switching valve (42).