JP3330405B2 - Injection equipment 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 an injection device for an injection molding machine, and more particularly, to an injection hydraulic cylinder (hereinafter, referred to as an injection cylinder) which operates constantly, and a plurality of accumulators (ACC) which selectively increase pressure. The present invention relates to an injection device of an injection molding machine in which the injection speed condition and the injection pressure condition can be variably set by appropriately combining the above.

[0002]

2. Description of the Related Art As is well known, injection speed and injection pressure, which are important in molding conditions in injection molding, are determined by the driving horsepower of a hydraulic pump of a machine (injection molding machine). That is, the driving horsepower, the injection speed, and the injection pressure of the hydraulic pump are obtained by the following equation: driving horsepower of the hydraulic pump = injection speed × injection pressure / 61
There is a relationship of 2, and the product of the injection speed and the injection pressure is proportional to the driving horsepower of the hydraulic pump. Therefore, the range of conditions of injection speed and injection pressure (capacity range of injection speed and injection pressure) that can be satisfied by one machine is naturally limited.

[0003] However, the objects of injection molding are wide-ranging, and a wide range of molding conditions are required according to the type of resin, the shape of the mold, and the like. Because it cannot cover all kinds of machines, it is necessary to purchase multiple types of machines depending on the application. For this reason, the demand for an injection molding machine that can satisfy a wide range of molding conditions with one machine has recently been increasing.

Therefore, a plurality of injection cylinders are mounted on one machine (for example, a plurality of injection cylinders are arranged in a straight line, or a plurality of injection cylinders are arranged symmetrically in parallel), and required molding conditions are set. An injection molding machine has recently been developed in which a combination of injection cylinders to be used is selected according to the conditions, and the conditions of the injection speed and the injection pressure are set to predetermined ones.

[0005]

However, in the injection molding machine equipped with a plurality of injection cylinders as described above, a mechanism has to be adopted in which the piston rod of each injection cylinder moves forward and backward integrally with the screw. Not used because there is no (do not supply pressurized oil during the injection stroke)
When an injection cylinder is set, the unused injection cylinder also idles, causing a problem that sliding resistance increases and energy loss increases.

Also, depending on the molding conditions, the filling process (1
In the injection molding machine equipped with a plurality of injection cylinders, the filling process is required to satisfy the low pressure and high speed in the filling process. Since the high pressure injection cylinder is not used during the injection, the pressure cannot be switched during the injection, and there is also a problem that it is not possible to simultaneously satisfy both the conditions of the low pressure and the high speed of the filling process and the high pressure of the pressure holding process.

Further, it has been pointed out that mounting a plurality of injection cylinders complicates the shape of the machine and increases the size of the machine.

Accordingly, a technical problem to be solved by the present invention is to solve the above-mentioned problems of the prior art.
The purpose is to have a wide range of conditions of injection speed and injection pressure, a small sliding load as compared with the above-described conventional technology, and a pressure switch during injection, which is relatively compact. An object of the present invention is to provide an injection device of an injection molding machine that can be configured.

[0009]

In order to achieve the above object, an injection device for an injection molding machine according to the present invention is connected to a piston rod of an injection cylinder, and is connected to a rear end of the screw. A moving block that moves forward and backward as a unit, and oil can be selectively supplied, and in a state where oil is supplied, a boosting operation is performed via the moving block that moves forward by the driving force of the injection cylinder,
This accumulator is provided with, for example, two accumulators having different boosting capacities to supply the pressurized oil to a forward oil chamber of the injection cylinder. By selecting whether or not each accumulator is to be pressurized, the injection speed condition and the injection speed are selected. It is configured to variably set the pressure condition.

In the present invention, preferably, the injection cylinder is a differential pressure cylinder, and a normal speed operation mode in which only oil from a hydraulic pump is supplied to a forward oil chamber;
High-speed operation mode in which oil from the hydraulic pump and oil from the reverse oil chamber are sent together to the forward oil chamber can be selected.
Be composed.

[0011]

In the injection stroke, the injection cylinder is always driven, and the moving block and the screw are advanced integrally with the piston rod of the injection cylinder. In the vicinity of the injection cylinder, two accumulators having different boosting capacities are provided, an accumulator to be used (operated for boosting) is selected according to a required molding condition, and an accumulator chamber (hereinafter, referred to as an accumulator) of the accumulator to be used.
The ACC chamber is supplied with oil. In the oil-supplied accumulator, the pressure-raising piston rod retreats, whereby the pressure-raising piston rod comes into contact with the moving block that moves forward by the driving force of the injection cylinder, and is pushed and moved forward by the moving force of the moving block. Then, the pressure of the oil in the ACC chamber is increased, and this pressurized oil is sent to the forward oil chamber of the injection cylinder. Accordingly, the oil from the hydraulic pump and the oil from the accumulator are supplied to the forward oil chamber of the injection cylinder, and the forward force is smaller than when only the injection cylinder is used alone without using the accumulator ( That is, although the resin pressure is low), a high speed is achieved.

Also, a normal speed operation mode in which only the oil from the hydraulic pump is fed to the forward oil chamber using the injection cylinder as a differential pressure cylinder, and the oil from the hydraulic pump and the backward oil chamber from the reverse oil chamber to the forward oil chamber. A high-speed operation mode in which oil and oil are fed together can be selected. When the high-speed operation mode is selected, so-called regeneration in which oil (excess oil) from the retreating oil chamber is sent to the forward oil chamber by a differential pressure circuit. Perform the operation,
Compared with the normal speed operation mode, the forward speed is small (that is, the resin pressure is low), but the speed is increased.

Therefore, the selection of whether to use one or two accumulators having different boosting capacities or no use thereof and the selection of the normal speed operation mode and the high speed operation mode of the injection cylinder described above are combined. As a result, eight injection speed conditions and injection pressure conditions can be set.

By doing so, the unused accumulator is in a state where the mechanical contact with the member driven forward by the injection cylinder is cut off (the edge is cut off).
The sliding load can be reduced as much as possible, and the energy loss can be suppressed. In addition, since the injection cylinder is constantly operating during the injection stroke, switching from low pressure to high pressure can be easily performed by, for example, relieving oil from the ACC chamber to the tank during injection. Furthermore, the accumulator can be made relatively small and simple as compared with a configuration in which a large number of injection cylinders are mounted, so that the entire machine can be made relatively compact.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. FIG. 1 is a cutaway plan view of a main part of an injection device of an injection molding machine according to the present embodiment, and FIG. 2 is a cutaway front view of a main part of the injection device of the injection molding machine according to the present embodiment.

1 and 2, reference numeral 1 denotes a holding block which is fixedly arranged during a continuous molding operation, 2 denotes a heating cylinder whose base end is held by the holding block 1, and 3 denotes a heating cylinder. Nozzle 4 attached to the tip side is a screw arranged so as to be able to rotate and move forward and backward in the heating cylinder 2, 5 is a raw material resin on the base end side of the heating cylinder 2 (the rear end side of the screw 4). A hopper for feeding and supplying

Reference numeral 6 denotes a screw rotation driving motor (electric motor or hydraulic motor) connected to the rear end side of the screw 4 via a rotary connection member 7, and the motor 6 is used during the kneading, plasticizing and measuring steps. The rotation drives the screw 4. Reference numeral 8 denotes a moving block which rotatably holds the rotary connecting member 7 via a bearing, and moves forward and backward integrally with the screw 4 and the motor 6.

Reference numeral 9 denotes an injection cylinder (hydraulic cylinder) which is a driving source for injection. In this embodiment, a pair is provided symmetrically with respect to the screw 4 in plan view.
The two injection cylinders 9 have the same configuration. The injection cylinder 9 is a double rod type differential pressure cylinder, and includes a forward oil chamber 10 and a reverse oil chamber 11.
In FIG. 1 and FIG. 2, the effective cross-sectional area of the piston body in the reverse oil chamber 11 is substantially completely volumeless. Reference numeral 12 denotes a double rod type piston rod of the injection cylinder 9 (hereinafter referred to as a piston rod 12).
), The distal end side of the rod portion on the small diameter side (forward oil chamber 10 side) of the piston rod 12 is
Attached to. Therefore, when the piston rod 12 of the injection cylinder 9 moves forward and backward, the moving block 8 also moves forward and backward integrally therewith.

Numeral 13 denotes an accumulator (A), and numeral 14 denotes an accumulator (B). In this embodiment, a pair is provided above and below each injection cylinder 9 when viewed from the horizontal direction. The accumulator (A) 13 has A
A pressure-raising piston rod 13b capable of moving back and forth in a CC (accumulator) chamber 13a is provided. One end of the pressure-raising piston rod 13b projects outward from the ACC chamber 13a and faces the moving block 8. ing.
The accumulator (B) 14 also has an ACC room 14.
a piston rod 14b capable of moving back and forth in
One end of the pressure-raising piston rod 14b also projects outward from the ACC chamber 14a and faces the moving block 8. The accumulators (A), (B) 13, 14 used in the present invention are different from general accumulators in which oil is pressurized by a high-pressure gas or a spring and stored and discharged, and the accumulators are provided in the ACC chamber 13a or 14a. When oil is supplied, the pressurizing piston rod 13b or 14b is moved by the moving block 8 as described later.
When the oil is pushed forward and moves forward (leftward in the figure), the oil is pressurized and discharged. In this embodiment, the boosting capacity of the accumulator (B) is set to be larger than that of the accumulator (A) 13.

FIG. 3 shows a main part of a hydraulic circuit including the injection cylinder 9 and the accumulators (A), (B) 13, 14. (The hydraulic circuit on only one side of the pair of injection cylinders 9 is shown. Shown). In the same 3, 21 is
The switching control valve for controlling the forward movement of the piston rod 12 of the injection cylinder 9, the neutral position is selected in the figure, but by switching the switching control valve 21 to the left position in the figure, a hydraulic pump (not shown) Oil is fed into the forward oil chamber 10 of the injection cylinder 9. Reference numeral 22 denotes a switching control valve for controlling differential pressure operation, which is provided in a pipeline between the reverse oil chamber 11 and the forward oil chamber 10 of the injection cylinder 9.
In the figure, the neutral position is selected, but by switching the switching control valve 22 to the left position in the figure, the forward oil chamber 10 and the reverse oil chamber 11 are connected, and the forward oil chamber 10 The oil can flow from the reverse oil chamber 11 to the reverse oil chamber 11 and from the reverse oil chamber 11 to the forward oil chamber 10. The switching control valve 22 is used to control the screw 4 during the well-known kneading, plasticizing, and metering processes in which the screw 4 is retracted by the pressure of the stored molten resin (at the time of the charging process), as well as the injection differential pressure of the injection cylinder 9 described later. At the time of operation (acceleration operation or high-speed operation), it is switched to the left position in the drawing where the forward oil chamber 10 communicates with the reverse oil chamber 11 (at least at this time, the forward oil chamber 10 and the reverse oil chamber 11 Is entered).

Reference numeral 23 denotes a switching control valve for the accumulator (A) 13, which is in the neutral position in FIG. 3, but is switched from a hydraulic pump (not shown) by switching the switching control valve 23 to the right position in the drawing. Is supplied to the ACC chamber 13a of the accumulator (A) 13, and the pressure-raising piston rod 13b projects toward the moving block 8. Further, by switching the switching control valve 23 to the left position in the drawing, the oil is returned from the ACC chamber 13a to the tank. Furthermore, when the switching control valve 23 is switched to the neutral position and the injection stroke is executed in a state where the ACC chamber 13a is filled with the oil, the moving block 8 which moves forward integrally with the piston rod 12 of the injection cylinder 9 increases the pressure. The piston rod 13b moves forward and the ACC chamber 13
The pressure in the oil in the ACC chamber 13a is sent to the forward oil chamber 10 of the injection cylinder 9 by increasing the pressure of the oil in the ACC chamber 13a.

Reference numeral 24 denotes a switching control valve for the accumulator (B) 14, which is in the neutral position in FIG. 3, but is switched from the hydraulic pump (not shown) by switching the switching control valve 24 to the right position in the figure. Is supplied to the ACC chamber 14a of the accumulator (B) 14, and the pressure-raising piston rod 14b projects toward the moving block 8. Further, by switching the switching control valve 24 to the left position in the figure, the oil is returned from the ACC chamber 14a to the tank. Further, when the switching control valve 24 is switched to the neutral position and the injection stroke is executed in a state where the ACC chamber 14a is filled with the oil, the pressure is increased by the moving block 8 which moves forward integrally with the piston rod 12 of the injection cylinder 9. The piston rod 14b moves forward and the ACC chamber 14
The pressure in the oil in the ACC chamber 14 a is sent to the forward oil chamber 10 of the injection cylinder 9.

Next, the operation of the above configuration will be described with reference to FIGS. In addition, ~ of FIG.
It corresponds to ~ in each column of FIG.

FIG. 4 shows an accumulator (A),
(B) A state in which only the injection cylinder 9 is operated at the normal speed operation without using the parts 13 and 14 (ie, the forward oil chamber 10 and the reverse oil chamber 11 of the injection cylinder 9 are cut off without communication). In this state, an operation state in which oil is fed into the forward oil chamber 10) is shown. In the operation mode of FIG.
The piston rod 12 of the injection cylinder 9 is attached to the forward oil chamber 1.
It moves forward by the force of the pressure oil sent directly from the hydraulic pump to 0,
In the operation mode of this embodiment, the highest injection pressure (highest resin pressure) is realized even at the lowest speed. The column of FIG. 5 shows the relative values of the resin pressure (corresponding to the injection pressure) and the injection speed of the entire machine at this time. Note that the injection speed in this case is the same as that of a conventional standard machine before a machine in which the operations of a plurality of injection cylinders are selectively combined, and the injection speed is set to 100%.

FIG. 4 shows an accumulator (A) 13.
And the state where the injection cylinder 9 is operated at the normal speed operation. In this case, as the piston rod 12 of the injection cylinder 9 advances, the accumulator (A)
13 is moved forward by the moving block 8, and the ACC of the accumulator (A) 13 is moved.
The oil in the chamber 13a is pressurized, whereby the ACC chamber 13a
The oil inside is fed into the forward oil chamber 10 of the injection cylinder 9 in such a manner as to be added to the oil from the hydraulic pump. Accordingly, the oil in the ACC chamber 13a is fed into the forward oil chamber 10 by the propulsive force of the piston rod 12 of the injection cylinder 9, so that the injection speed becomes higher and the resin pressure becomes lower than in FIG.

FIG. 4 shows an accumulator (B) 14.
And the state where the injection cylinder 9 is operated at the normal speed operation. In this case, as the piston rod 12 of the injection cylinder 9 advances, the accumulator (B)
14 is moved forward by the moving block 8, and the ACC of the accumulator (B) 14
The oil in the chamber 14a is pressurized, whereby the ACC chamber 14a
The oil inside is fed into the forward oil chamber 10 of the injection cylinder 9 in such a manner as to be added to the oil from the hydraulic pump. Since the capacity of the accumulator (B) 14 is higher than the capacity of the accumulator (A) 13, the injection speed becomes higher and the resin pressure becomes lower than in FIG.

FIG. 4 shows an accumulator (A) 13.
And the accumulator (B) 14 is used, and the injection cylinder 9 is operated at the normal speed operation. In this case, the piston rod 12 of the injection cylinder 9
With the advance, the piston rod 13b for increasing pressure of the accumulator (A) 13 and the piston rod 14b for increasing pressure of the accumulator (B) 14 advance by the moving block 8, and pressurize the oil in the ACC chamber 13a and the ACC chamber 14a. Thereby, the oil in the ACC chambers 13a and 14a is fed into the forward oil chamber 10 of the injection cylinder 9 in a form to be added to the oil from the hydraulic pump. Accordingly, the propulsive force of the piston rod 12 of the injection cylinder 9 causes A
Since the oil in the CC chambers 13a and 14a is fed into the forward oil chamber 10, the injection speed becomes higher and the resin pressure becomes lower than in FIG.

FIG. 4 shows an accumulator (A),
(B) A state in which only the injection cylinder 9 is operated by an acceleration operation (differential pressure operation) without using 13 and 14 (that is, the forward oil chamber 10 and the reverse oil chamber 11 of the injection cylinder 9 communicate with each other). Operating state in which a differential pressure circuit is formed). 4, the piston rod 12 of the injection cylinder 9 receives the forward force by the force of the pressure oil directly fed from the hydraulic pump into the forward oil chamber 10, and the piston rod 12 and the forward oil chamber 10 In accordance with the cross-sectional area difference from the oil chamber 11, a forward force is also received by the oil discharged from the reverse oil chamber 11 and sent to the forward oil chamber 10 via the differential pressure circuit (regeneration circuit). Therefore, of course, the injection speed is higher than that of FIG. 4 and the resin pressure is lower. In this embodiment, in the case of the operation mode of FIG. 4, the injection speed is higher than that of FIG. It is configured to be low pressure.

FIG. 4 shows an accumulator (A) 13.
Is used to operate the injection cylinder 9 in an acceleration operation (differential pressure operation). In this case, the above-described differential pressure operation of the injection cylinder 9 and the operation of the accumulator (A) 13 in the case of FIG. 4 are combined, and the injection speed becomes higher than that of FIG. The pressure will be low.

FIG. 4 shows an accumulator (B) 14.
Is used to operate the injection cylinder 9 in an acceleration operation (differential pressure operation). In this case, the differential pressure operation of the injection cylinder 9 and the operation of the accumulator (B) 14 in the case of FIG.
The injection speed is higher and the resin pressure is lower than in FIG.

FIG. 4 shows an accumulator (A) 13.
2 shows a state in which both the injection cylinder 9 and the accumulator (B) 14 are used and the injection cylinder 9 is operated by an acceleration operation (differential pressure operation). In this case, the differential pressure operation of the injection cylinder 9 and the accumulators (A) and (B) 1 shown in FIG.
The combination of the operations 3 and 14 results in a higher injection speed and a lower resin pressure than in FIG.

As described above, in the present embodiment, selection is made as to whether one or two of the two types of accumulators (A), (B) 13, 14 are used, or whether they are not used at all.
By combining the selection of the normal speed operation mode and the high speed operation mode of the injection cylinder 9 described above, eight injection speed conditions and injection pressure conditions can be set.

In this way, the unused accumulator (A) 13 or (B) 14 is disconnected from the moving block 8 driven forward by the injection cylinder 9 (the edge is cut off). ), The sliding load can be reduced as much as possible, and the energy loss can be suppressed.

Since the injection cylinder 9 is always operating during the injection stroke, for example, the ACC chamber 13a,
By relieving the oil from 14a to the tank,
Switching from low pressure to high pressure is also easy.

Since the accumulator of the present embodiment can be made relatively small and simple as compared with the conventional configuration in which a large number of injection cylinders are mounted, the whole machine can be made relatively compact.

Although the present invention has been described with reference to the illustrated embodiments, it is obvious that those skilled in the art can make various modifications without departing from the spirit of the present invention.
If three or more accumulators are attached to the injection cylinder, the injection speed and the injection pressure can be selected and set more finely. Further, in the above-described embodiment, the example in which the injection cylinder paired with the machine is mounted is shown, but the injection cylinder mounted in the machine may be a single injection cylinder.

[0037]

As described above, according to the present invention, for example, two accumulators having different boosting capacities are attached to an injection cylinder, and one or two accumulators are used or no accumulator is used at all. Selection and
By combining the selection of the normal speed operation mode and the high speed operation mode of the injection cylinder described above, eight injection speed conditions and injection pressure conditions can be set.

The unused accumulator is in a state where the mechanical contact with the moving block driven forward by the injection cylinder is cut off (cut off the edge), so that the sliding load can be reduced as much as possible, and the energy can be reduced. Loss can be suppressed. In addition, since the injection cylinder is constantly operating during the injection stroke, switching from low pressure to high pressure can be easily performed by, for example, relieving oil from the ACC chamber to the tank during injection. Compared to a configuration in which a large number of injection cylinders are mounted, the accumulator can be made relatively small and simple, so that the entire machine can be made relatively compact. Play.

[Brief description of the drawings]

FIG. 1 is a fragmentary plan view of an injection device of an injection molding machine according to one embodiment of the present invention.

FIG. 2 is a fragmentary front view of an injection device of the injection molding machine according to one embodiment of the present invention.

FIG. 3 is an explanatory diagram showing a main part hydraulic circuit used in the injection device of the injection molding machine according to one embodiment of the present invention.

FIG. 4 is an explanatory diagram showing eight types of operation modes realized by one embodiment of the present invention.

5 is an explanatory diagram showing a relationship between a combination of operations of an injection cylinder and two accumulators corresponding to FIG. 4 and a resin pressure and an injection speed.

[Description of Signs] 2 Heating cylinder 4 Screw 8 Moving block 9 Injection cylinder 10 Forward oil chamber 11 Reverse oil chamber 12 Piston rod 13 Accumulator (A) 13a ACC (accumulator) chamber 13b Boosting piston rod 14 Accumulator (B) 14a ACC (accumulator) chamber 14b Piston rod for pressure rise

Claims (4)

(57) [Claims] 1. An injection device for an injection molding machine for injecting a molten resin into a mold by advancing a screw in a heating cylinder, wherein the injection device is connected to a piston rod of an injection hydraulic cylinder and a rear end of the screw. And a moving block that moves forward and backward integrally with the screw, and is capable of selectively supplying oil. When the oil is supplied, the pressure is increased through the moving block that moves forward by the driving force of the injection hydraulic cylinder. And at least one or more accumulators for performing the operation and supplying the pressurized oil to a forward oil chamber of the injection hydraulic cylinder,
An injection apparatus for an injection molding machine, wherein an injection speed condition and an injection pressure condition can be variably set by selecting whether or not the accumulator is to be boosted. 2. The injection molding machine according to claim 1, wherein a plurality of the accumulators are provided for the injection hydraulic cylinder, and whether or not each of the accumulators is operated to increase the pressure can be individually selected. Injection device. 3. The injection device of an injection molding machine according to claim 2, wherein the plurality of accumulators have different boosting capacities. 4. The normal hydraulic operation mode according to claim 1, wherein the injection hydraulic cylinder is a differential pressure cylinder, and a normal speed operation mode in which only oil from a hydraulic pump is supplied to a forward oil chamber. And a high-speed operation mode in which oil from the hydraulic pump and oil from the retraction oil chamber are sent together.
An injection device for an injection molding machine, which is selectable.