JPH0531780A - Injection apparatus - Google Patents

Abstract

PURPOSE:To enable injection speed to be controlled over the wide range by connecting each pressure chamber partitioned by the piston of an accelerating device to the lubricating ports of an infection cylinder via each auxiliary opening and closing valve. CONSTITUTION:Injection-operating oil is enabled to be supplied to lubricating ports 50, 51 of an injection cylinder 6 via a main opening and closing valve 21. and there is provided an accelerating device 30 comprising a cylinder mechanism of double-rod type piston 32 and being imparted with a differential of the piston pressure area and a piston driving device. By connecting each pressure chamber 32L, 32R partitioned by the piston 32 in the accelerating device 30 to the lubricating ports 50, 51 of the injection cylinder 6 via each auxiliary opening and closing valve 22, 23, operating oil in the pressure chamber is enabled to be calculation-supplied so that the injection speed is controlled and fluidity of resin is enhanced greatly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection device using synthetic resin, synthetic rubber or the like, and more particularly to an injection device using a speed increasing device capable of obtaining a higher injection speed.

[0002]

2. Description of the Related Art An injection device is one in which a material resin is put into a molding cylinder in which a screw is inserted and melted, and then the screw is advanced to inject the molten resin into a mold cavity. The forward movement of the screw is performed by a hydraulic cylinder connected to the rear end of the screw.

By the way, the injection speed of the material resin is determined by the advancing speed of the screw, and the injection pressure is determined by the advancing strength of the screw. In particular, in recent years, it has been found that the injection pressure should be reduced and the injection speed should be increased in the case of thin-walled molded products, while the injection pressure should be increased and the injection speed should be reduced in the case of thick-walled molded products. . By making the adjustment range of such injection pressure and injection speed remarkably wide, it is possible to mold thick and thin molded products.
As shown in FIG. 3, several kinds of rams 15 having different diameters are connected to the rear end of the screw, and each ram 15 has a cylinder chamber 16, which are connected to the screw via a connecting rod 18. Some have been proposed.

[0004]

However, since each of the above-mentioned cylinder chambers 16 must have the maximum injection stroke of the molding machine, the total length of the injection cylinder when the cylinder chambers 16 are connected becomes long and space is saved. There is a problem in that it is disadvantageous in terms of.

[0005]

In order to solve such a problem, in the present invention, injection hydraulic oil can be supplied to an oil supply port of an injection cylinder through a main opening / closing valve, and a double rod type A piston is provided with a speed increasing device consisting of a cylinder mechanism to which a piston pressure receiving area difference is applied and a piston drive device, and each pressurizing chamber defined by the piston of this speed increasing device is injected through a sub opening / closing valve. By connecting to the oil supply port of the cylinder, the hydraulic oil in the pressurized chamber can be additionally supplied. Further, the piston driving device is formed by the hydraulic chamber containing the piston rod, and the pressure receiving areas of the left and right rods are made different. I made it up.

[0006]

Operation: A speed increasing device is added so that hydraulic oil can be supplied to the injection cylinder of the injection device to change the injection speed over a wide range. This speed increasing device is equipped with a cylinder to which the pressure receiving area of the piston is given, and a ram that can change the pressure receiving area on both sides of the piston. Since the injection speed can be changed by supplying the oil to the cylinder oil port, the fluidity of the resin is greatly increased.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of an injection device using a speed increasing device according to the present invention will be described in detail with reference to the accompanying drawings. Figure 1
It is sectional drawing of the injection device which concerns on the Example of this invention. Code 1
Is a forming cylinder, in which the nozzle 3 is projected to the front and a material feeding hopper 10 is attached to the upper surface of the rear.
The molding cylinder 1 melts the material resin and then injects it from the nozzle 3 and injects it into the cavity of the mold 4.
A band heater 11 for heating the forming cylinder 1 is wound around the outer periphery of the forming cylinder 1, and a screw 2 is rotatably inserted therein. The screw 2 serves both as a kneading mechanism that melts the material resin while kneading it and an injection mechanism that pushes out the melted resin, and the screw 2 advances and retracts while rotating itself.

Reference numeral 6 is an injection cylinder, which has a piston 6a and a piston rod 6 which are slidably provided in the inside thereof.
b, and the rear end side of the piston rod 6b is fixed to the block 7. On the other hand, the above-mentioned screw 2 is connected to the block 7 via a connecting rod 8 on the rear end of which a screw flight is not engraved. The screw 2 can be rotated by a motor 5 fixed to the rear end of the block 7. Further, the injection cylinder 6 causes the screw 2 to move in the forward / backward direction. In addition,
Reference numeral 35 is a check valve, and 50 and 51 are refueling ports.

Reference numerals 21, 22, and 23 are electromagnetic switching valves. Reference numeral 30 is a speed increasing device, which has three working chambers 3
1, 33, 34, a piston 32, and three different-diameter rams 36, 37, 38. The working chamber 31
Has a larger diameter than the other working chambers 33 and 34, and a piston 32 is provided inside thereof so as to be slidable back and forth. In FIG. 1, a small-diameter ram 36 is fixed to the left side of the piston 32, and the small-diameter ram 36 moves left and right in the working chamber 33 as the piston 32 moves forward and backward. A ram 37 having a relatively small diameter is fixed to the right side of the piston 32, and a small ram 38 is fixed to the right side of the ram 37 so as to be on the same axis as the ram 37. The small-diameter rams 37 and 38 are configured to move right and left in the working chamber 34.

Further, the working chamber 33 and the working chamber 31 are divided into partitions 3
3a, the partition 33a is formed with an insertion hole for the ram 36, and the ram 36 is slidably disposed therein. Further, the working chamber 33 and the working chamber 31 are structured so that there is no leakage of hydraulic oil. Similarly, working chamber 3
1 and the working chamber 34 are separated from each other by a partition 34a, and an insertion hole for a ram 37 is formed in the partition 34a, and the ram 37 is slidably arranged therein. The working chamber 31 and the working chamber 34 are structured such that no hydraulic oil leaks from each other.

Further, in the speed increasing device 30, pressurizing chambers 32L and 32R are provided on the left and right sides of the piston 32, respectively, and a difference in pressure receiving area is provided between the pressurizing chambers 32L and 32R. Now, the diameter of the ram 36 is d ₁ , the diameter of the ram 37 is d, the diameter of the ram 38 is d ₂ , the inner diameter of the working chamber 31 is D, and the working chamber 31 is
Let L be the inner length of L and the piston width be L ₁ , the maximum amount of hydraulic oil Q ₁ stored in the pressurizing chamber 32L of the working chamber 31 is Q ₁
= [(Π / 4) · (D ² −d ₁ ² )] × (L−L ₁ ), and similarly, the maximum amount of hydraulic oil stored in the pressurizing chamber 32R of the working chamber 31 is Q ₂ = [ (Π / 4) · (D ² −d ² )]
× a _{(L-L 1).} Therefore, Q ₁ and Q ₂ (d> d
₁₎ In the ^{[(π / 4) · (d} 2 -d 1 2) ] × (L-L
₁ ), the amount of hydraulic oil stored in Q ₁ becomes larger than the amount of hydraulic oil stored in Q ₂ .

The leftward or rightward speed of the piston 32 is determined by the amount of hydraulic oil supplied to the working chamber 33 or 34. For example, hydraulic oil supplied to the working chamber 33 becomes a force for pressing the area A ₁ of the end face of the ram 36 _{(= (π / 4) d} 1 2) on the right side, as long as the piston 32 hydraulic oil amount is constant The rightward speed is constant. As a result, the oil is introduced into the pressurizing chamber 6R through the oil supply port 50 of the injection cylinder 6, and the leftward speed of the piston 6a, that is, the injection speed is determined. Similarly, the hydraulic oil supplied to the working chamber 34 serves as a force for pressing the pressure receiving area difference A ₂ (= (π / 4) · (d ² −d ₂ ² )) of the rams 37 and 38 to the left. Further, the amount of hydraulic oil supplied to the working chambers 33, 34 may be changed in order to increase the injection speed.

Next, as shown in FIG. 1, the injection cylinder 6
Is provided with a pump 42 for supplying hydraulic oil, and a supply pipe 44 is connected to a discharge port of the pump 42. The flow control valves 40 and 60 are installed in the pump 42 to operate the hydraulic oil while controlling the amount of hydraulic oil. I try to supply oil. The supply pipeline 44 is further branched into a pipeline 45 communicating with the electromagnetic switching valve 21 as a main opening / closing valve and a pipeline 46 communicating with the electromagnetic switching valve 24. The hydraulic fluid that has passed through the pipe 45 is supplied from the flow rate control valve 60 and the electromagnetic switching valve 21 to the pressurizing chambers 6L and 6R of the injection cylinder 6 via the oil supply ports 51 and 52. On the other hand, the pipeline 46
The hydraulic fluid passing through the flow control valve 40, the electromagnetic switching valve 24, the electromagnetic switching valve 2 as a sub opening / closing valve via the speed increasing device 40.
2 and 23 are supplied to the pressurizing chambers 6L and 6R of the injection cylinder 6 through the oil supply ports 51 and 52. The electromagnetic switching valves 21, 22, 23, and 24 are 4-port 3-position switching valves, which connect the pump 42 to the pressurizing chamber 6R and move the screw 2 forward (moving supply port position (a solenoid activation), Neutral position where both pressurizing chambers 6R and 6L are opened to the tank 43, and pressurizing chamber 6 on the side where the screw 2 is retracted
The hydraulic oil is supplied to L, and the other pressurizing chamber 6R is opened to the tank 43. The reverse discharge port position (b solenoid activation) can be switched to three positions. In FIG. 1, reference numeral 41 is a relieve valve.

The operation of the injection device using the speed increasing device configured as described above is as follows. In recent years, the injection device is required to move the screw 2 at a high speed from the backward limit to the forward limit. This is for the following reasons. That is, since a large shear stress is generated between the molten resin and the mold 4 by injecting the molten resin at a high speed, the temperature of the resin becomes high, the viscosity is lowered, and the fluidity is improved.

First, in the present invention, the use of the speed increasing device 30 makes it possible to adjust the injection speed in the following five stages.
That is, the injection speed v ₁ when the solenoid a of the electromagnetic switching valve 21 is activated to supply the hydraulic oil to the pressurizing chamber 6R (the speed increasing device 30
Is not used). The solenoid a of the electromagnetic switching valve 23 is activated and the solenoid b of the electromagnetic switching valve 24 is activated. Further, the injection speed v ₂ when the hydraulic oil is supplied to the pressurizing chamber 6R in combination with the speed increasing device 30. The injection speed v ₃ when the solenoid a of the electromagnetic switching valve 22 and the solenoid a of the electromagnetic switching valve 24 is activated and the speed increasing device 30 is also used to supply hydraulic oil to the pressurizing chamber 6R. Injection speed v ₄ when hydraulic oil is supplied to the pressurizing chamber 6R in combination with the above. Injection speed v ₅ when hydraulic oil is supplied to the pressurizing chamber 6R in combination with the above. And the injection speed is v ₁ <v ₂ <v ₃ <v
_It becomes larger in the order of ₄ <v ₅ .

(1) In the case described above; the electromagnetic switching valve 21
A solenoid of the other is started, and the other electromagnetic switching valves 22, 2
3 and 24 are cases where the neutral position is maintained and the speed increasing device 30 is not used. As a result, the hydraulic oil is supplied from the pump 42 to the pressurizing chamber 6R of the injection cylinder 6 via the flow control valve 60 and the electromagnetic switching valve 21 from the pump 42, and the screw 2 starts to move forward at the injection speed v _1. To do. The pressurizing chamber 6L is driven by the leftward movement of the piston 6a in the injection cylinder 6.
The hydraulic oil therein is opened to the tank 43 via the electromagnetic switching valve 21.

(2) In the case described above; the electromagnetic switching valve 23
In addition to activating the solenoid a, the solenoid b of the electromagnetic switching valve 24 is activated, and the speed increasing device 30 is also used. The hydraulic oil is supplied from the pump 42 to the working chamber 33 of the speed increasing device 30 through the supply pipe 46 and the electromagnetic switching valve 24. By the movement of the piston 32, the pressurizing chamber 32R
When the amount of hydraulic oil of Q ₂ (<Q ₁ ) stored inside is supplied to the pressurizing chamber 6R of the injection cylinder 6 via the electromagnetic switching valve 23, the screw 2 starts to move forward at the injection speed v _2. . At this time, the electromagnetic switching valves 21, 22 are in the neutral position, and the hydraulic oil in the pressurizing chamber 6L is released to the tank 43 via the electromagnetic switching valve 21 by the leftward movement of the piston 6a in the injection cylinder 6.

(3) In the case described above; the electromagnetic switching valve 22
And each a solenoid of the electromagnetic switching valve 24 is activated, and the speed increasing device 30 is also used. The hydraulic oil is supplied from the pump 42 to the working chamber 34 of the speed increasing device 30 through the supply pipe 45 and the electromagnetic switching valve 24. Q ₁ (> Q ₂ ) stored in the pressurizing chamber 32L by the movement of the piston 32
Is supplied to the hydraulic chamber 6R of the injection cylinder 6 via the electromagnetic switching valve 22, the screw 2 causes the injection speed v ₃
To start moving forward. At this time, the electromagnetic switching valves 21, 23 are in the neutral position, and the hydraulic oil in the pressurizing chamber 6L is released to the tank 43 via the electromagnetic switching valve 21 by the leftward movement of the piston 6a in the injection cylinder 6.

(4) In the case described above; solenoid switching valve 2
1, a solenoids a and 23 are activated, and a solenoid b of the solenoid operated directional control valve 24 is activated.
Used together. When hydraulic oil is supplied from the pump 42 to the working chamber 33 of the speed increasing device 30 through the supply pipe 46 and the electromagnetic switching valve 24, the movement of the piston 32 causes Q ₂ stored in the pressurizing chamber 32R to be stored. The hydraulic oil amount (<Q ₁ ) is supplied to the pressurizing chamber 6R of the injection cylinder 6 via the electromagnetic switching valve 23. At the same time, the pressure chamber 6 of the injection cylinder 6 passes from the pump 42 through the supply pipe 45 and the electromagnetic switching valve 21.
The hydraulic oil amount Q ₃ is supplied to R and added (Q ₂ +
Q _3). Thus, the screw 2 starts to move forward at the injection speed v ₄ . At this time, the electromagnetic switching valve 22 is in the neutral position,
By the leftward movement of the piston 6a in the injection cylinder 6, the hydraulic oil in the pressurizing chamber 6L is transferred to the tank 43 via the electromagnetic switching valve 21.
Open to the public.

(5) In the case described above; solenoid switching valve 2
The a solenoids 1, 22, 24 are activated, and the speed increasing device 30 is also used. The working chamber 34 of the speed increasing device 30 passes from the pump 42 through the supply pipe 46 and the electromagnetic switching valve 24.
When the working oil is supplied to the pressurizing chamber of the injection cylinder 6 via the electromagnetic switching valve 22, the amount of hydraulic oil of Q ₁ (> Q ₂ ) stored in the pressurizing chamber 32L by the movement of the piston 32 is increased. Hydraulic oil is supplied to 6R. At the same time, the injection cylinder 6 passes from the pump 42 through the supply pipe 45 and the electromagnetic switching valve 21.
The hydraulic oil amount Q ₃ is supplied and added to the pressurizing chamber 6R (Q ₁ + Q ₃ ). Thus, the screw 2 has an injection speed v
Start to move forward at ₅ . At this time, the electromagnetic switching valve 23 is in the neutral position, and the hydraulic oil in the pressurizing chamber 6L is released to the tank 43 via the electromagnetic switching valve 21 by the leftward movement of the piston 6a in the injection cylinder 6.

[0021]

As is apparent from the above description, in the present invention, the injection hydraulic oil can be supplied to the oil supply port of the injection cylinder via the main opening / closing valve.
It is a double rod type piston equipped with a speed increasing device consisting of a cylinder mechanism and a piston drive device with a difference in piston pressure receiving area, and each pressurizing chamber defined by the piston of this speed increasing device is connected via a sub opening / closing valve. By connecting to the oil supply port of the injection cylinder, the hydraulic oil in the pressurized chamber can be additionally supplied. Further, the piston drive device is formed by a hydraulic chamber containing the piston rod, and the pressure receiving areas of the left and right rods are made different. By doing so, the injection speed can be adjusted over a wide range. As a result, the fluidity of the resin increases and the pressure in the mold cavity
The temperature is less biased from place to place, making it possible to mold large-sized molded products and ultra-thin molded products, and to greatly improve transferability. In addition, the molding distortion is reduced, and in the case of multi-cavity production in particular, variations in cavities are eliminated and the quality of molded products is improved. Furthermore, the injection speed can be easily adjusted by simply adding a speed increasing device having a simple structure and compactness to the existing injection device.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an injection device according to an embodiment.

FIG. 2 is an explanatory diagram of a speed increasing device according to an embodiment.

FIG. 3 is a conventional speed increasing device.

[Explanation of symbols]

1 forming cylinder 2 screws 3 nozzles 5 motor 6 injection cylinder 6a, 32 piston 21, 22, 23, 24 Solenoid switching valve 30 speed increasing device 31, 33, 34 Working chamber 32 pistons 34,36,38 Ram 6L, 6R, 32L, 32R Pressurizing chamber 40,60 Flow control valve 41 relief valve 42 pumps 43 tanks 50,51 Refueling port

Claims (2)

[Claims] 1. An injection hydraulic oil can be supplied to an oil supply port of an injection cylinder through a main opening / closing valve, and is composed of a cylinder mechanism and a piston drive device which are both rod type pistons and are provided with a piston pressure receiving area difference. Equipped with a speed increasing device, each pressurizing chamber defined by the piston of this speed increasing device was connected to the oil supply port of the injection cylinder via each sub-opening / closing valve to enable additional supply of hydraulic oil in the pressurizing chamber. An injection device characterized by the above. 2. The injection device according to claim 1, wherein the piston drive device is formed by a hydraulic chamber that contains the piston rod, and the pressure receiving areas of the left and right rods are made different.