JP2874675B2 - 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 molding machine, and more particularly to an injection molding machine in which a plunger is moved by generating a high-pressure hydraulic oil pressure by an air-hydro booster.

[0002]

2. Description of the Related Art Conventionally, there have been the following injection molding machines. That is, as shown in FIG. 3, the injection molding machine 1 includes a high-pressure air source 53 that generates a pressure used for injection molding, and an air-hydro booster 55 that converts the pressure of the high-pressure air source 53 into a high-pressure hydraulic oil pressure. And high pressure air source 5
The solenoid valve 57 is disposed between the air hydraulic booster 3 and the air-hydro booster 55 and switches between supply and discharge of high-pressure air. The cylinder mechanism 61 moves the plunger 59 by high-pressure hydraulic pressure generated from the air-hydro booster 55. . Then, the cylinder mechanism 61 is engaged with the cylindrical cylinder 61a and the plunger 59 so that the cylinder 61a
Of the two pressure chambers 62a, 62b formed by the piston 61b and the cylinder 61a, only the pressure chamber 62a on the side corresponding to the pressurizing direction of the plunger 59 is air-hydrodynamic. The booster 55 is connected.

Here, the air-hydro booster 55 is
A pressure device that converts high-pressure air into high-pressure hydraulic oil pressure using mineral oil as hydraulic oil. The pressure increase ratio is determined by the square of the piston diameter on the input side and output side, that is, the piston area ratio. Is done. For example, if the area of the input side piston 55a is 500 [cm ² ] and the area of the output side piston 55b is 10 [cm ² ], when the pressure of the input high pressure air is 0.4 [MPa], the output high pressure Since the hydraulic oil pressure increases by 50, a pressure of 20 [MPa] can be obtained.

The function of the injection molding machine 51 constructed as described above when it operates in the direction of pressing the plunger 59 (upward) will be described. First, the high-pressure air generated by the high-pressure air source 53 is controlled by the regulator 63. The pressure is regulated and supplied to the solenoid valve 57. The solenoid valve 57 supplies high-pressure air to the air-hydro booster 5 through the one-way flow path 57a.
5

[0005] In the air-hydro booster 55, the high-pressure air from the high-pressure air source 53 operates an internal pressure-raising mechanism. Specifically, as described above, the input side piston 5
The diameter of 5a is larger. Therefore, the piston 55a on the input side is pushed rightward by the high-pressure air. Thus, the output side piston 55b is also pushed rightward. Here, the right side of the piston (small diameter) on the output side is filled with hydraulic oil S and is converted into a high hydraulic oil pressure.

Next, the high-pressure hydraulic oil pressure is applied to the cylinder mechanism 6.
1 is transmitted. The cylinder mechanism 61 includes a cylinder 61a.
And three sets of pistons 61b. The plunger 59 is engaged with the piston 61b.
Two pressure chambers 62a and 62b are formed in the cylinder 61a with the piston 61b as a boundary. In this conventional example, the above-described air-hydro booster 55 is connected to the pressurizing side of the plunger 59 (below the piston), so that high-pressure hydraulic oil pressure is transmitted. Therefore, in the injection molding process, the piston 61b moves up. vice versa,
The upper side of the piston is filled with air, and is discharged through the solenoid valve 57 with the rise of the piston 61b.

On the other hand, when returning the plunger 59 to the pressure reducing direction, the one-way flow path of the solenoid valve 57 is switched, and the pressure chamber 62b above the piston 61b of the cylinder mechanism 61
Is supplied with high-pressure air from a high-pressure air source 53. Therefore,
The high pressure air pushes down the piston 61b, and the plunger 59 returns in the pressure reducing direction (downward). FIG. 4 is a sectional view showing a state in which the plunger 59 is compressing the material in the mold.

[0008]

However, the above conventional example has the following disadvantages. That is, the conventional injection molding machine 1 uses the air-hydro booster 55 only when moving the plunger 59 in the pressurizing direction, and uses high-pressure air when moving the plunger 59 in the depressurizing direction. The thrust on the piston 61b in the pressure reducing direction is less than that in the pressure direction. As a result, the sliding resistance between the plunger 59 and the mold pot 67 causes a problem that the operation of the plunger 59 in the decompression direction becomes uncertain.

[0009]

SUMMARY OF THE INVENTION It is an object of the present invention to improve the disadvantages of the prior art and to provide an injection molding machine capable of reliably moving the plunger in both the pressurizing direction and the depressurizing direction of the plunger. I do.

[0010]

According to the present invention, there is provided an injection molding machine comprising: a high-pressure air source for generating a pressure used for injection molding;
An air-hydro booster for converting the pressure of the high-pressure air source into a high-pressure hydraulic oil pressure, a solenoid valve disposed between the high-pressure air source and the air-hydro booster for switching supply / discharge of high-pressure air, and an air-hydro booster And a cylinder mechanism for moving the plunger by high-pressure hydraulic pressure generated from the cylinder.

The cylinder mechanism comprises a cylindrical cylinder and a plunger piston which is engaged with the plunger and moves in the cylinder, and is provided in both of the two pressure chambers formed by the plunger piston and the cylinder. Connect the air-hydro booster, and to the solenoid valve,
A configuration is adopted in which a high-pressure air supply channel for supplying high-pressure air is provided only to the air-hydro booster corresponding to one of the pressure chambers.

With the above configuration, the high-pressure hydraulic oil pressure converted by the air-hydro booster is used for both the case where the plunger is moved in the pressurizing direction and the case where the plunger is moved in the depressurizing direction. Therefore, it is possible to reliably operate the plunger not only in the pressurizing direction but also in the depressurizing direction. In particular, hydraulic oil is advantageous in that it is less likely to be compressed than air and has a small change in volume.

[0013] Further, according to the second aspect of the present invention, the air-hydro booster has a pressure increasing function of generating a high-pressure hydraulic oil pressure higher than the pressure of the air of the high-pressure air source. This is the same as the invention described in 1. With the configuration described above, a high-pressure hydraulic oil pressure higher than the air pressure of the high-pressure air source can be generated.

Further, according to the third aspect of the invention, the cylinder mechanism has a plurality of cylinders and a plunger piston, and each cylinder is connected to each other by a hydraulic pipe. Or, it is the same as the invention described in 2. With the configuration described above, the same high-pressure hydraulic oil pressure is transmitted to each cylinder. Thereby, the plunger also moves at the same pressure.

[0015]

Next, embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the injection molding machine 1 of the present embodiment generates a pressurized air source 3 for use in injection molding, and converts the pressurized pressure of the high-pressure air source 3 into a high-pressure hydraulic oil pressure. Air-hydro boosters 5, 6, a solenoid valve 7 disposed between the high-pressure air source 3 and the air-hydro boosters 5, 6 for switching supply / discharge of high-pressure air, and a high pressure generated from the air-hydro boosters 5, 6. A cylinder mechanism 11 for moving the plunger 9 by operating hydraulic pressure. The cylinder mechanism 11 includes a cylindrical cylinder 11a, a plunger piston 11b that is engaged with the plunger 9 and moves in the cylinder 11a, and includes the plunger piston 11b and the cylinder 1a.
The air-hydro boosters 5 and 6 are connected to both of the two pressure chambers 12a and 12b formed by the pressure chamber 1a, and one of the pressure chambers 1a and 12b is connected to the solenoid valve 7.
A high-pressure air supply channel for supplying high-pressure air is provided only to the air-hydro booster 5 corresponding to 2a.

This will be described in detail below.
Is a pressure generating device such as a compressed air pump, which pressurizes air introduced from the outside and supplies it to a pneumatic circuit. A regulator 4 is provided downstream of the high-pressure air source 3. The regulator 4 regulates high-pressure air generated by the high-pressure air source 3 to a predetermined pressure. The pressure gauge 2 is connected to the outlet side of the regulator 4 so that the pressure of the high-pressure air after the pressure adjustment can be confirmed.

A predetermined solenoid valve 7 is provided downstream of the regulator 4. The solenoid valve 7 has a function of switching supply and discharge of high-pressure air to and from the air-hydro boosters 5 and 6 described below. More specifically, various one-way flow paths 7a are formed in the solenoid valve 7, and by switching between the flow paths and the pipes connected to the air-hydro boosters 5, 6, the air-hydro booster 5.6 is connected. It is designed to work. In FIG. 1,
A case is shown in which high-pressure air is supplied to one air-hydro booster 5 corresponding to the pressurizing direction of the plunger 9 and air is discharged from the other air-hydro booster 6 corresponding to the depressurizing direction.

Next, the air-hydro boosters 5 and 6 will be described. The air-hydro boosters 5 and 6 receive high-pressure air, increase the pressure, and convert the pressure into high-pressure hydraulic oil pressure using mineral oil as hydraulic oil. It is determined by the square of the piston diameter of the two pistons 5a and 5b mounted on the device, that is, the piston area ratio. That is, the air-hydro boosters 5 and 6 are connected to two cylinders having different inner diameters, and the pistons 5 having different diameters corresponding to the respective cylinders are provided.
a, 5b, 6a and 6b are housed inside. Also,
Compression springs 5c, 6c are arranged in contact with the large-diameter pistons 5a, 6a, and when no high-pressure air is supplied, the pistons 5a, 5b, 6a, 6b return to their original positions. It has become.

A cylinder mechanism 11 is provided downstream of the air-hydro boosters 5, 6. The cylinder mechanism 11 is for pressing the plunger 9 for injection molding. More specifically, the cylinder mechanism 11 includes a cylindrical cylinder 11a and the cylinder 11a.
And a plunger piston 11b disposed at the center. Pressure chambers 12a and 12b are formed on both sides with the plunger piston 11b as a boundary.
Hydraulic pipings 15a and 15b of the two air-hydro boosters 5 and 6 are connected to a and 12b, respectively. The cylinder 11a is filled with high-pressure hydraulic oil S, so that high-pressure hydraulic oil pressure can be transmitted between the cylinders 11a and the small-diameter pistons 5b, 6b of the air-hydro boosters 5, 6.

The cylinder mechanism 11 is provided with three sets of cylinders 11a and plunger pistons 11b, each of which is connected by a hydraulic pipe 17. Therefore, the lower pressure chamber 12a of the plunger piston 11b
, The same pressure is transmitted.

The function of the injection molding machine 1 configured as described above for moving the plunger 9 to the side to be pressurized will be described. First, the high-pressure air generated by the high-pressure air source 3 is regulated by the regulator 4. , Supplied to the solenoid valve 7. The solenoid valve 7 supplies high-pressure air to one air-hydro booster 5 through the one-way flow path 7a.

In this one air-hydro booster 5,
The high-pressure air from the high-pressure air source 3 activates the internal pressure increasing mechanism. Specifically, the large-diameter piston 5a of the air-hydro booster 5 is pushed rightward. Thereby, the small diameter piston 5b is also pushed rightward. Here, the right side of the small-diameter piston is filled with hydraulic oil, and is converted into a high-pressure hydraulic oil pressure.

Next, the high-pressure hydraulic oil pressure is applied to the cylinder mechanism 1
1 is transmitted. The transmitted high-pressure hydraulic oil pressure is sequentially transmitted to the pressure chambers 12a of the cylinders 11a, and the plunger piston 11b is pushed upward. At this time,
Since each cylinder 11a is filled with high-pressure hydraulic oil of the same pressure, each plunger piston 11b is pressed by the same force. Then, the plunger 9 engaged with the plunger piston 11b moves (upwards), and an injection operation is performed. At this time, the hydraulic oil is also filled in the pressure chamber 12b on the upper side of the plunger piston 11b. However, as the plunger piston 11b rises, it flows toward the other air-hydro booster 6 and the small-diameter piston 6b in the air-hydro booster 6 (To the left in the figure). And the large diameter piston 6a also moves to the left similarly.

As shown in FIG. 1, the pneumatic system of the other air-hydro booster 6 is communicated to the outside by a solenoid valve 7, so that the internal air is discharged to the outside. Thereby, the pressurization process of injection molding is completed.

On the other hand, when returning the plunger 9 to the pressure reducing side, as shown in FIG. 2, the one-way flow path 7a of the solenoid valve 7 is switched, and high-pressure air is supplied to the other air-hydro booster 6. In this case, the high-pressure hydraulic oil pressure is transmitted to the pressure chamber 12b on the upper side of the plunger piston 11b of the cylinder mechanism 11, contrary to the case described above. Therefore, the plunger piston 11b moves downward.
As a result, the plunger piston 11b descends, and the plunger 9 returns in the pressure reducing direction.

[0027]

Next, embodiments of the present invention will be described with reference to the drawings. In this embodiment, the high-pressure air generated by the high-pressure air source 3 is supplied at 0.4 to 0.5 MPa, and is regulated by the regulator 4 to a pressure set in a range of 0.1 to 0.3 [MPa]. Is done. For example, regulator 4
Is 0.2 [MPa], 0.2 [MPa]
Is supplied to one air-hydro booster 5 by a solenoid valve 7.

The supplied high-pressure air is increased by a factor of 50 by the air-hydro booster 5 to 10 [MPa], and raises the plunger piston 11b through the pipe 15a using mineral oil as hydraulic oil.

Conversely, when the plunger 9 is moved in the pressure reducing direction, the high-pressure air regulated to 0.2 [MPa] by the regulator 4 is supplied to the other air-hydro booster 6 by the solenoid valve 7. . The supplied high pressure air is
The pressure is increased 50 times by the air-hydro booster 6 and 10
[MPa], hydraulic oil 15
The plunger piston 11b is lowered through b. In particular, since the hydraulic oil has a smaller volume change than the air, the plunger piston mounted on each cylinder can be pushed down uniformly. Thus, a series of injection molding steps is completed.

[0030]

As described above, the present invention utilizes the high-pressure hydraulic oil pressure increased by the air-hydro booster for the cylinder mechanism in both the pressurizing direction and the depressurizing direction of the plunger. In addition to the case where the plunger is sometimes moved to the pressure side, an excellent effect that the operation failure due to the sliding resistance with the mold when returning the plunger after the end of the injection molding can be surely prevented is produced.

Further, since the air-hydro booster presses the plunger with a high-pressure hydraulic oil pressure higher than that of the high-pressure air source, there is an excellent effect that a higher molding pressure can be obtained in the injection molding process.

Further, since a plurality of cylinders and a plunger piston are provided in the cylinder mechanism, and the respective cylinders are connected to each other by the hydraulic pipe, an excellent effect that a plurality of molded products can be manufactured at one time is produced. .

[Brief description of the drawings]

FIG. 1 is a pneumatic / hydraulic circuit diagram showing an embodiment of the present invention, particularly showing a state in which a plunger has moved in a pressing direction.

FIG. 2 is a pneumatic / hydraulic circuit diagram of the injection molding machine disclosed in FIG. 1, particularly showing a state in which a plunger has moved in a pressure reducing direction.

FIG. 3 is a pneumatic / hydraulic circuit diagram showing a conventional example.

FIG. 4 is a cross-sectional view illustrating a state in which a material in a mold is pressed by a plunger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection molding machine 3 High pressure air source 5 Air-hydro booster 6 Air-hydro booster 7 Solenoid valve 9 Plunger 11 Cylinder mechanism 11a Cylinder 11b Plunger piston 12a Pressure chamber 12b Pressure chamber 17 Hydraulic pipe

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B29C 45/53-45/54 B29C 45 / 02,45 / 58,45 / 17 B29C 45/82 B22D 17 / 32

Claims (3)

(57) [Claims] 1. A high-pressure air source for generating a pressure used for injection molding, an air-hydro booster for converting the pressure of the high-pressure air source into a high-pressure hydraulic oil pressure, and a mutual connection between the high-pressure air source and the air-hydro booster. An injection molding machine provided with a solenoid valve that switches between supply and discharge of high-pressure air and a cylinder mechanism that moves a plunger by high-pressure hydraulic pressure generated from the air-hydro booster. A cylinder and a plunger piston engaged with the plunger and moving in the cylinder, and an air-hydro booster is connected to both one and the other two pressure chambers formed by the plunger piston and the cylinder. An air-hydro booster corresponding to one of the pressure chambers of the solenoid valve; Only an injection molding machine comprising: a high pressure air supply passage for supplying the high pressure air. 2. The injection molding machine according to claim 1, wherein the air-hydro booster has a pressure increasing function of generating a high-pressure hydraulic oil pressure higher than the pressure of the air of the high-pressure air source. 3. The injection molding machine according to claim 1, wherein the cylinder mechanism includes a plurality of cylinders and a plunger piston, and the cylinders are connected to each other by a hydraulic pipe.