JPH0447916A - Driving mechanism in injection molder - Google Patents

Abstract

PURPOSE:To make it possible equalize utilizations by time of the minimum and maximum necessary capacities and installed capacity of motors, and the minimum and maximum necessary capacities and installed capacity of power transducers for controlling the motors by a method wherein the transmission objects of the turning forces of driving means are changed over through gears by a first and a second transmitting means. CONSTITUTION:In a metering and back pressure applying process, a clutch 46 is turned ON and a screw 40 is rotated through the rotation of a motor 48 so as to accumulate molten resin in a cylinder 50, resulting in shifting a stand 54 on members 56a and 56b by means of the pressure of said resin. At this time, a clutch 44 is turned OFF, resulting in transmitting no rotation of the motor 49 to an intermediate gear 43. In an injecting and dwelling process, the clutch 46 is turned OFF and the clutch 44 is turned ON so as to synchronize the rotation of the motor 48 through a coupling 42, the clutch 44 and the gear 43 with the rotation of motors 60a and 60b through couplings 42a and 42b and gears 68a and 68b at both the sides of the gear 43.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to metering, back pressure, injection and
The present invention relates to a drive mechanism in an injection molding machine that performs a pressure holding process.

[Conventional technology] Conventionally, measuring, back pressure, injection and
In the pressure holding process, the metering process is executed by the first motor,
Furthermore, the back pressure, injection, and pressure holding processes are executed by another second motor.

An example of this prior art is shown in FIG.

In the metering/backpressure process of an injection molding machine, the metering/injection screw 2 is connected to a motor 6 via a coupling 4, and when the motor 6 rotates, the metering/injection screw 2 rotates and the resin is Weighing takes place. The rotation of the motor 6 is controlled by a feedback signal obtained from a position detector 10 attached to the motor 6 to a specified rotation speed via a controller (not shown).

As the metering/injection screw 2 rotates and the resin is metered, molten resin is accumulated in the metering/injection cylinder 12, and the resin pressure of the accumulated molten resin causes the metering/injection screw 2, A force acts to retract the coupling 4, motor 6, and metering/injection table 14, and the cylinder table 20 as a whole is retracted.

At this time, each ball screw 30a is connected to two ball screws 24a and 24b mounted under the measuring/injection table 14 via couplings 28a and 28b of two motors 26a and 26b, The two motors 26a and 26b are rotated synchronously so as to apply a force that does not move the metering/injection table 14 backward through the motor 30b. This allows back pressure to be applied. The rotations of the two motors 26a, 26b are controlled in synchronization with a torque specified by a controller (not shown) by feedback signals obtained from respective position detectors 32a, 32b attached to these motors.

In the injection/pressure holding process of an injection molding machine, the molten resin accumulated in the metering/injection cylinder 12 during the metering/backpressure process is clamped in advance by moving the metering/injection screw 2 forward. The resin mold 36 is filled with the resin.

At this time, since the metering/injection screen -2 has a backflow prevention ring attached to its tip, it will not be reversed due to backflow caused by the filling pressure of the molten resin. Therefore, at this time, the motor 6 connected to the metering/injection screw 2 via the coupling 4 does not need to rotate, and the feedback signal obtained by the position detector 10 attached to the motor 6 causes the Since there is no need for the motor 6 to be controlled to a specified rotation speed by a controller that does not operate, the motor 6 is in a controlled-out state, that is, in a free state.

Now, in order to advance the metering/injection screw 2, for the same reason as explained in the metering/back pressure process, the two motors 26a, 26b are synchronized, and the two motors 26a, 26b are The respective ball screws 30a, 30b engaged through the respective couplings 4 are rotated in synchronization. Thereby, two ball nuts (24a) are attached under the metering/injection table 14.

The two motors 26a and 26b may be rotated in synchronization so as to exert a force on the metering/injection table 14 on the metering/injection table 24b. At this time, the rotation of the two motors 26a, 26b is controlled by feedback signals obtained from the respective position detectors 32a, 32b attached to the two motors 26a, 26b. They are controlled synchronously at a specified rotation speed corresponding to the forward speed pattern of No. 2, that is, the injection pattern.

In this way, the molten resin accumulated in the metering and injection cylinder 12 can be injected and filled into the resin mold. However, simply injecting and filling in this way tends to cause problems such as pulling when the resin mold and resin are cooled, and molding defects are likely to occur. For this purpose, after injection and filling, pressure is continued to be applied to the molten resin injected and filled into the resin mold 36 in order to prevent the above-mentioned problems. In other words, holding pressure is applied. This means that two motors 26a and 2 are connected to two ball nuts 24a and 24b installed under the weighing/injection table 14.
The two motors 26a and 126b are synchronized so as to exert a force that advances the metering/injection table 14 through respective ball screws 30a and 30b which are coupled to the motor 6b through respective couplings 28a and 28b. rotate it,
It can be realized. The rotation of the two motors 26a, 26b is caused by the respective position detectors 32 attached to them.
With the feedback signals obtained by a and 32b,
The metering/injection screw 2 is controlled in synchronization with a specified torque corresponding to a preset advance pattern of the metering/injection screw 2, that is, a pressure holding pattern, via a controller (not shown).

[Problems to be Solved by the Invention] As described above, in the process of metering, back pressure, injection, and pressure holding in electrification of an injection molding machine, the metering process is performed by the motor 6, and the process of back pressure, injection, and pressure holding is performed by the motor 6. is performed by other motors 26a and 26b.

In this case, the following may be considered as an example of the motor capacity required in each of the above steps.

Metering...28kW Back pressure...8kW Injection...
4 (]kW Holding pressure...90kW In this example, the metering process is performed by motor 6, and the back pressure, injection, and holding pressure processes are performed by the other motors 26a and 126b.The motor capacity is selected as follows. I can think of things.

Measuring motor capacity: 28kW Back pressure/Injection/
Pressure holding motor capacity: 90 kW (2 units of 45 kW x 2) In addition, as the required power supply capacity for the entire motors 6.26a, 26 tl and motor control power converter in this example, the overall efficiency of each is 80%. If this is specified, the following can be considered.

Motor power supply capacity: 147.50kW Motor control power converter power supply capacity: 140.63kW If the above is summarized and expressed in a systematic diagram, it will be as shown in Figure 4, and if expressed according to the passage of time, it will be as follows: , as shown in Figure 5.

Looking at the motor here, the minimum/maximum required capacity...36/90 kW installed capacity
...126kW, and looking at the power converter for motor control, the minimum/maximum required capacity...45/112.5kW, and the installed capacity...147.5kW. In other words, about 1/3 to 2/3 of the installed capacity is always in a dormant state on a time-average basis. This does not make effective use of equipment and is not economical.

[Object of the Invention] The present invention has been made to overcome the above-mentioned disadvantages, and its purpose is to promote leveling of the time-averaged utilization of equipment and improvement of efficiency, as well as to An object of the present invention is to provide a drive mechanism for an injection molding machine that simplifies the process and achieves a low overall manufacturing cost.

[Means for Solving the Problems] In order to solve the above problems, the drive mechanism in the injection molding machine of the present invention includes: a metering/injection screw, a movable metering/injection table, and a first drive mechanism. a first drive means for rotationally driving a shaft; a second drive means fixed to the metering/injection table and rotationally driving a second drive shaft; and a second drive means for rotationally driving a second drive shaft; a first transmission means that is connected as necessary to transmit the rotational driving force of the first drive shaft to the metering/injection screw; a gear that connects the first drive shaft and the second drive shaft; The first drive shaft and the gear or the first gear and the second drive shaft.
a second drive shaft that is disposed between the drive shafts, connects the first drive shaft and the second drive shaft as necessary, and transmits the rotational driving force of the first drive shaft to the second drive shaft; and a displacement means that is connected to the second drive shaft and displaces the metering/injection table toward the metering/injection screw based on the rotational driving force of the second drive shaft. It is characterized by

[Function] In the injection molding machine of the present invention configured as described above, the drive mechanism transmits the rotational force of the drive means to the gear during the metering/back pressure, injection/pressure holding processes in electrification. and the minimum/maximum required capacity/installed capacity of the drive means and the minimum/maximum required capacity/installed capacity of the power converter for controlling the drive means in time. The usage rate seen will be leveled out. Furthermore, for movable parts other than the metering/injection cylinder and the metering/injection screw, a lightweight, easy-to-configure injection table and displacement means are used. This simplifies the configuration of the movable part mechanism.

[Embodiment] Next, a preferred embodiment of a drive mechanism in an injection molding machine according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1aSb shows an injection molding machine to which the drive mechanism of the injection molding machine of this embodiment is applied.

This injection molding machine includes a metering/injection screw 40 that handles the steps of metering, injection a, and pressure holding, a coupling 42 connected to this, a hollow gear 43 disposed in a gear box 52, and a hollow clutch. 44, a motor 48 connected via a clutch 46, and the metering/injection valve mentioned above! J, -40 is screwed into the measuring device where resin is accumulated.
An injection cylinder 50 is provided.

These structures are arranged on a movable weighing/injection table 54, which has sliding members 56a, 56b.
It is movably placed on the base 58 and moves on the base 58. Furthermore, couplings 42a and 4 are mounted on the weighing/injection table 54.
2b and two motors 60a, 60b connected to this
is fixed. Furthermore, it includes two ball nuts 62a, 62b fixed to the metering/injection cylinder 50, and ball screws 64a, 64b screwed therein,
Gears 68a, 68b disposed within the gear box 52 are engaged with the ball screws 64a, 64b, and their ends are fixed to the couplings 42a, 42b.

The motors 48, 60a, 60b are equipped with a position detector 7 for controlling the rotation speed or torque specified by a controller (not shown) using a feedback signal.
2.72a and 72b are provided.

Further, a cylinder stand 74 is fixed to the base 58, and the measuring/injection cylinder 50 is mounted on the cylinder stand 74 with a ball screw 64a screwed into the pole nuts 62a, 62b.
, 64b.

Note that a resin molding die 80 is attached to a fixing member (not shown) at the tip of the metering/injection cylinder 50.

The operation in the above configuration will be explained below.

In the metering/back pressure process, the metering/injection screw 40 is connected to the motor 48 via a coupling 42, a hollow clutch 44, and a clutch 46, and the clutch 46 is in the N state during the metering/back pressure process. Both end shafts are connected.

Therefore, by rotating the motor 48, the metering/injection process is completed! J, -40 is rotated and the resin is measured.

The rotation of the motor 48 is controlled by a feedback signal obtained from an attached position detector 72 to a rotation speed specified by a controller (not shown).

And then, the measurement/injection step! J, -40 rotates to measure the molten resin, and the molten resin is accumulated in the metering/injection cylinder 50, and the resin pressure of the accumulated molten resin causes the metering/injection screw 40, gear box 52, and metering - A force for retracting the injection table 54 acts, and the weighing/injection table 54 moves on the sliding members 56a and 56b provided on the base 58.

In this case, the two motors 60a and 60b are attached to the metering/injection table 54, and since the hollow clutch 44 is in the OFF state and the shafts at both ends are separated during the metering/back pressure process, the motor 48 Rotation is not transmitted to hollow gear 43.

For this purpose, two ball nuts (62a) are installed inside the cylinder stand 74 on the base 58.

62b, respective ball screws 64a, 64b coupled to two motors 60a, 60b via respective couplings 42a, 42b and respective gears 68a, 68b.
Back pressure can be applied by rotating the two motors 60a and 60b synchronously on both sides of the hollow gear 43 so as to apply a force that does not move the metering/injection table 54 backward. . Two motors 60a, 6
The rotation of 0b is determined by each of the attached position detectors 72a,
? 2b, the torque is controlled to a specified value by a controller (not shown).

In the injection/pressure holding process of an injection molding machine, the molten resin accumulated in the measuring/injection cylinder 50 during the above-mentioned measuring/backpressure process is clamped in advance by moving the measuring/injection valve +J+s-40 forward. The resin is filled into the mold 80 for resin molding. At this time, the metering/injection screw 40 has a backflow prevention ring attached to its tip, so that it will not be reversed due to backflow caused by the filling pressure of the molten resin.

At this time, measure and inject! J: The motor 48, which is coupled to L-40 via the coupling 42, hollow clutch 44, and clutch 46, does not need to rotate, and due to the feedback signal obtained by the position sensor 72 attached to the motor 48, The motor 48 does not need to be controlled to a specified rotation speed from a controller (not shown).
may be controlled out, that is, in a free state, so that both end shafts can be separated with the clutch 46 in the OFF state.

Here, measure and inject! In order to advance the J, -40, the two motors 60a, 60b are rotated to rotate the respective ball screws 64a, 64b for the same reason as explained in the metering/back pressure process. As a result, the two motors 6 are operated so as to exert a force to advance the metering/injection table 54 from the two ball nuts 62a and 62b attached inside the cylinder table 74 on the base 58.
All you have to do is rotate 0a and 60b. At this time, motor 48
is in a free state, so the hollow clutch 44 is turned on and both ends are connected, so that the rotation of the motor 48 is transmitted to the hollow gear 43, and the rotation of the motor 48 is connected to the couplings 42a, 42b and the hollow clutch. 4.4 and the rotation via the hollow gear 43, the rotation of the two motors 60a, 60b is coupled to each coupling 42a, 42b and each gear 6
Both sides of the hollow gear 43 are rotated in synchronization with the rotation via the gears 8a and 68b. Therefore, the force for advancing the metering/injection table 54 is obtained by the sum of the rotations of the two motors 60a and 60b and the rotation of the motor 48. In such a case, the rotation of the two motors 60a160b is controlled by the feedback signals obtained from the position detectors 72a and 72b attached to each, and the rotation of the motor 48 is controlled by the feedback signals obtained from the position sensor 72, as shown in the figure. Measuring and injection steps that are preset by the controller! J: Two motors 60 corresponding to the forward speed pattern of L-40, that is, the injection pattern
The a 160b and the motor 48 are controlled to be synchronized on both sides of the hollow gear 43 at designated rotation speeds.

In this way, the molten resin accumulated in the metering and injection cylinder 50 can be injected and filled into the resin mold. However, simply injecting and filling in this way tends to cause problems such as pulling when the resin mold and resin cools, resulting in molding defects, so it is necessary to prevent the above problems after injection and filling. For this purpose, pressure is continued to be applied to the molten resin injected and filled into the resin molding die 80. In other words, holding pressure is applied. this is,
Measuring is carried out from the ball screws 62a, 62b attached to the inside of the cylinder stand 74 on the base 58 through the respective ball screws 64a, 164b, which are connected to the respective couplings 42a, 42b via the respective gears 68a, 68b. - This can be realized by rotating the two motors 60a160b so as to exert a force that moves the injection table 54 forward. At this time, as in the previous case, the motor 48
is in a free state, the clutch 46 is in the OFF state and both end shafts are separated, and the hollow clutch 44 is in the ○N state.
Since both ends are connected in the state shown in FIG. , 68b on both sides of the hollow gear 43. Therefore, the force for advancing the metering/injection table 54 is obtained by the sum of the rotations of the two motors 60a, 60b and the motor 48.

In such a case, the rotation of the two motors 60a, 60b is controlled by the feedback signals obtained by the respective attached position detectors 72a, 72b, and also by the rotation of the two motors 60a, 60b.
The rotation of No. 8 corresponds to the forward pressure cover turn of the metering/injection screw 40, that is, the pressure holding pattern, which is preset by a controller (not shown), based on a feedback signal obtained by the position detector 72 attached to the motor 48. These two motors 60a, 60b
and the rotation of the motor 48 with the torque specified for each motor 48, and the rotation of the two motors 60a, 60b through the respective couplings 42a, 42b and the respective gears 68a, 68b on both sides of the hollow gear 43. Control to synchronize.

In the embodiment described above, the rotational driving force of the motor 48 is transmitted to the motors 60a and 60b via the hollow clutch 44 attached to the hollow gear 43, but the gears 68a and 68b are and these gears 6
It is also possible to mount the hollow clutches 44 on the motors 8a and 68b so as to transmit the rotational driving force of the motor 48 to the motors 60a and 60b.

Further, as an alternative to the two motors 60a, 60b and the motor 48 used in this embodiment, a hydraulic motor may be used. In addition, a hollow gear 43 and two gears 68a
, 68b, it is also possible to use a hollow boob, two boob groups, and a belt.

In the embodiments described above, the following motor capacities are considered necessary for each process.

Metering...28kW Back pressure...8kW Injection...
・40kW holding pressure...90kW - 48 motors
The process of back pressure, injection, and holding pressure is carried out by the other two motors 6.
0a and 60b, the following selection of motor capacity can be considered.

Motor capacity for metering, injection, and pressure holding: 30 kW Motor capacity for back pressure, injection, and pressure holding: 60 kW (2 units of 30 kW x 2) In addition, the motors 48, 60a, 60b, and Assuming that the total efficiency of each motor control power converter is defined as 80%, the following is considered as the required power supply capacity for the motor control power converter.

Motor power supply capacity: 112.50 kW Motor control power converter power supply capacity: 140.63 kW In this embodiment, the steps of metering, injection, and pressure holding are summarized in FIG. 2. Note that the time course is the same as in FIG. 5.

Looking at the motor here, the minimum/maximum required capacity...36/90 kW installed capacity
...9(]kW), and looking at the power converter for motor control, the minimum/maximum required capacity...45/112.5kW, and the installed capacity...112.5kW. As a result, the equipment capacity will no longer be idle on an hourly average basis.Furthermore, the equipment utilization rate will increase from 31/76% to 40/100.
%, and the installed capacity can be reduced to about 3/4. In addition, injection molding machine metering, back pressure, injection, holding pressure,
In the process of back pressure, injection, and holding pressure, by configuring the movable parts other than the metering/injection cylinder and metering/injection screenie with sliding members, ball screws, and ball nuts, The movable part mechanism can be simplified.

[Effects of the Invention] As described above, according to the drive mechanism in the injection molding machine of the present invention, the minimum/maximum required capacity and installed capacity of the motor and the minimum/maximum required capacity and installed capacity of the motor control power converter can be improved. The usage rate in terms of time has been leveled, improving the efficiency of equipment usage, and the injection molding machine's metering/back pressure, injection/pressure-holding movable parts mechanisms such as the metering/injection cylinder and metering/injection screw. There is an advantage that the movable part mechanism can be easily constructed by configuring the movable parts other than the above with, for example, a sliding member, a ball screw, or a pole nut.

In addition, it has the effect of achieving low manufacturing costs.

[Brief explanation of the drawing]

FIG. 1a is a plan view showing the configuration of an embodiment of the drive mechanism in the injection molding machine of the present invention, FIG. 1 is a side view of the embodiment shown in FIG. 1a, and FIG. Figure 3a is a plan view showing the configuration of the drive mechanism in a conventional injection molding machine, and Figure 3a is a diagram used to explain the power required for the drive mechanism in such an injection molding machine Figure 4 is a side view of the drive mechanism in an injection molding machine. Figure 4 is a diagram used to explain the required power of the drive mechanism in a conventional injection molding machine. Figure 5 is a diagram showing the required power of the drive mechanism in an injection molding machine over time. It is a figure provided for explanation. 40...Measuring/injection screw 42.42a, 42b...Coupling 43...Hollow gear 44...Hollow clutch 46...Clutch 48...Motor 50...Measuring/injection cylinder 52... ...Gear box 54...Measuring/injection table 56a, 56b...Sliding member 58...Base 60a, 60b...Motor 62a, 62b...Pole nut 64a, 64b...Ball screw 68a, 68b - Gears 72a, 72b...Position detector 74...Cylinder stand 80...Resin molding mold FIG, 2

Claims (1)

[Claims] (1) A metering/injection screw, a first drive means fixed to a displaceable metering/injection table and rotationally driving a first drive shaft, and a second drive shaft fixed to the metering/injection table. a second drive means for rotationally driving the metering/injection screw; and a second driving means for connecting the metering/injection screw and the first drive shaft as necessary to transmit the rotational driving force of the first drive shaft to the metering/injection screw. a gear that connects the first drive shaft and the second drive shaft; and a gear that connects the first drive shaft and the gear or the gear and the second drive shaft;
A second drive shaft is disposed between the drive shafts, connects the first drive shaft and the second drive shaft as necessary, and transmits the rotational driving force of the first drive shaft to the second drive shaft. A transmission means; and a displacement means that is connected to the second drive shaft and displaces the metering/injection table toward the metering/injection screw based on the rotational driving force of the second drive shaft. A drive mechanism in an injection molding machine.