JPH03256714A - Injection driving mechanism - Google Patents

Abstract

PURPOSE:To improve utilization efficiency of a driving device by connecting if necessary a metering and injecting screw with the first spline shaft by means of the first transmitting device, connecting if necessary the first spline shaft with the second spline shaft by means of the second transmitting device and displacing the metering and injecting screw by means of a displacing device. CONSTITUTION:The second gear train is constituted of a gear 76 connecting a motor 42 which is the second driving device and a spline gear 78 slidably fitted in the second spline shaft 62 and the first gear train is constituted of a gear 64 connecting a motor 44 which is the first driving device and a spline gear 68 slidably fitted in the second spline shaft 62. One end of the spline shaft 62 is connected with a ball screw 46 and another end thereof is connected with a spline shaft 60 by means of the second transmitting device. Another end of the spline shaft 60 is connected with a metering and injecting screw 52 by means of the first transmitting device. Metering is performed by means of the first driving device and a back pressure is applied by means of the second driving device and injection and dwelling are performed by means of the first and the second driving devices.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an injection drive mechanism that can improve the utilization efficiency of drive means involved in the steps of metering, back pressure, injection, and pressure holding in an injection molding machine.

[Background of the Invention] Conventionally, in order to execute each process of measuring, back pressure, injection, and holding pressure in an injection molding machine, the first
A second motor is used to carry out back pressure, injection, and pressure holding processes.

An example of this prior art is shown in FIGS. 3(a) and 3(b).

In this injection molding machine, a motor 14 that receives back pressure, injection, and pressure holding processes is installed on a base surface 38.
A position detector 12 is attached to 4. Motor 1
A coupling 16 is attached to 4, and a ball screw 18 is attached to the coupling 16. The ball screw 18 is connected to a measuring/injection table 32 placed on a sliding surface 30.
It is screwed into a ball nut 36 attached to. A motor 22 for carrying out the metering process is attached to the metering/injection table 32, and like the motor 14, a position detector 20 and a coupling 24 are attached to the motor 22.

The coupling 24 is fitted with a metering and injection screw 26 which is coupled to a metering and injection cylinder 28 mounted on a cylinder base 34. The conventional injection molding machine is configured as described above.

Next, the operation of a conventional injection molding machine will be explained. In the metering and backpressure steps of the injection molding machine, the rotation of the motor 22 causes the metering/injection screw 26 coupled to the motor 22 to rotate, thereby metering the resin for injection molding.

The rotation of the motor 22 is controlled to a specified rotation speed by feeding back a signal obtained from the position detector 20 attached to the motor 22 to a controller (not shown). As the metering/injection screen 5-26 rotates and the injection molding resin is metered, the molten injection molding resin is accumulated in the metering/injection cylinder 28. Then, due to the resin pressure of the accumulated molten resin for injection molding, the metering/injection screen: L-26, the coupling 24
, the motor 22, and the force that moves the entire metering/injection table 32 backward. At this time, the motor 14 is rotated to perform the above-mentioned weighing and
Back pressure can be applied to the molten resin for injection molding by applying a force that does not move the injection table 32 backward. The rotation of the motor 14 is controlled to a specified torque by feeding back a signal obtained from a position detector 12 attached to the motor 14 to a controller (not shown).

In the injection and pressure holding process of the injection molding machine, the molten resin for injection molding accumulated in the metering/injection cylinder 28 during the above-mentioned metering and backpressure process is removed by advancing the metering/injection screen 5-26. It is filled into a mold (not shown) that has been clamped in advance.

Here, in order to advance the metering/injection screw 26,
In the same way as explained in the above-mentioned measurement and back pressure process, the motor 14 is rotated, and the coupling 16 and ball screw 18 are
, a force may be applied to advance the metering/injection table 32 via the pole nut 36. The rotation of the motor 14 is
By feeding back a signal obtained by the position detector 12 attached to the motor 14 to a controller (not shown), a preset forward speed pattern of the metering/injection screw 26, that is, a specified pattern corresponding to the injection pattern is determined. The rotation speed is controlled to the specified rotation speed.

In this way, the molten resin for injection molding accumulated in the metering/injection cylinder 28 can be injected into the mold and filled. However, simply injecting and filling in this way tends to cause problems such as pulling when the mold and resin cools, resulting in molding defects, so continue to apply pressure to the molten resin after injection and filling. . In other words, a holding pressure is applied.

This can be achieved by rotating the motor 14 and exerting a force that moves the metering/injection table 32 forward. The rotation of the motor 14 is controlled by feeding back a signal obtained by the position detector 12 attached to the motor 14 to a controller (not shown) to control the forward pressure cover turn of the metering/injection screw 26, that is, the holding pressure. The torque is controlled according to the pattern.

[Problems to be Solved by the Invention] By the way, in each of the weighing, back pressure, injection, and pressure holding steps of the injection molding machine controlled in this way, the motor 22 is used to carry out the weighing step, and the back pressure is A motor 14 is used to carry out the pressure, injection, and pressure holding processes. In this case, the following capacity can be considered as the required capacity of the motor 14.22 for executing each process.

Measurement... 7kW Back pressure... 2kW injection...
・10kW Holding pressure...15kW Therefore motor 14
．． The following capacity is required for 22.

Capacity of the metering motor 22: 7 kW Capacity of the back pressure, injection, and pressure holding motor 14: 15 kW In addition, when the capacity of the motor 14.22 is set as above, the motor control When the efficiency is defined as 80%, the power supply capacity required for the power converter is as follows.

Total motor power capacity: 27.50 kW Total power converter power capacity for motor control: 23.44 kW The above is summarized in FIGS. 4 and 5.

Now, looking at motor 14.22, the minimum/maximum required capacity...9/15kW installed capacity...
...22kW, and looking at the power converter for motor control, the minimum/maximum required capacity...11.25/18.75kW installed capacity...
...27.50kW. In other words, on average over time, about 1/3 to 1/2 of the installed capacity is always in a dormant state. This is not only a waste of equipment, but also a waste of product costs.

If we consider the rating of the motor in this case in more detail, we can consider the following based on the above.

Motor 22...7kW, 400rpm Motor 14...
- The following are the general rating ranges for a 15kW, 4oorpm standard motor.

Rated capacity: 0.5kW to 15kW Rated rotation speed: 11,000rpm to 3,000rpm or more If this is done, the mechanical configuration is very simple and inexpensive, but the metering and back pressure of the injection molding machine , injection, and pressure holding processes, it becomes impossible to select a motor from the range of standard motors, resulting in unnecessary costs for the product.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned disadvantages, and it is an object of the present invention to improve the utilization efficiency of the drive means for carrying out the steps of metering, back pressure, injection, and pressure holding in an injection molding machine, and to An object of the present invention is to provide an injection drive mechanism that can achieve low cost.

[Means for achieving the object] In order to achieve the above object, the present invention includes: a metering/injection screw; first and second driving means for driving the metering/injection screw; first and second spline shafts, the driving side of which is connected to the first driving means, the slave side of which is in sliding contact with the first spline shaft, and the driving force of the first driving means is transferred to the first spline shaft. a first gear train that transmits the driving force of the second driving means to the second spline shaft; a driving side is connected to the second driving means; a driven side is in sliding contact with the second spline shaft; a second gear train that transmits transmission to the second spline shaft, the metering/injection screw, and the first spline shaft as necessary;
a first transmission means for transmitting the rotational driving force of the first spline shaft to the metering/injection screw; and a first transmission means for connecting the first spline shaft and the second spline shaft as necessary; a second transmission means for transmitting the rotational driving force of the second spline shaft to the first spline shaft; 1 spline shaft, the second transmission means, and a displacement means for displacing the metering/injection screw via the second spline shaft and the first transmission means.

[Function] According to the present invention, when the steps of metering, back pressure, injection, and pressure holding of an injection molding machine are performed using two drive means, in the metering/back pressure step, the first drive means The metering/injection screw is rotated through the first gear train, the first spline shaft, and the first clutch to meter the resin, while the second gear train and the second spline shaft are rotated by the second drive means. The displacing means is driven through the displacer to displace the metering/injection screw and apply back pressure to the resin or the like. Next, during the injection/holding process, the first and second driving means drive the displacement means via the first and second spline shafts to displace the metering/injection screw to inject and hold the resin, etc. Perform holding pressure.

[Embodiments] Next, preferred embodiments of the injection drive mechanism according to the present invention will be described in detail with reference to the accompanying drawings.

FIGS. 1(a) and 1(a) show an injection molding machine to which the injection drive mechanism according to this embodiment is applied.

In this injection molding machine, a gear box 82 is mounted on the base 70.
A gear box 80 is attached to the gear box 82, and the gear box 82 includes a gear 76 constituting a second gear train and a spline gear 78 with a spline passing through the center, and has back pressure, injection, and holding pressure. A motor 42, which is second driving means, is connected to the gear 76. A gear 64 and a spline gear 68 constituting a first gear train are installed in the gear box 80, and a motor 44, which is a first driving means having a metering, injection, and pressure holding process, is connected to the gear 64. connected to. Further, position detectors 40 and 50 are attached to the motor 42 and the motor 44, respectively.

On the other hand, the spline gear 7 installed in the gear box 82
A second spline shaft 62 is slidably fitted into the spline shaft 8.
The first spline shaft 60 is slidably fitted into a spline gear 68 housed in the gear box 80 .

One end of the spline shaft 62 is coupled to a coupling 72 provided between the ball screw 46 and the spline shaft 62, and the other end is connected to a second transmission means provided between the spline shaft 62 and the spline shaft 60. It is coupled to a certain clutch 66.

Further, one end of the spline shaft 60 is connected to the clutch 66 described above, and the other end is connected to a clutch 74 which is a first transmission means provided between the spline shaft 60 and the metering/injection screw 52.

The metering/injection screw 52 is connected to the metering/injection cylinder 5
4, and the metering and injection cylinder 54 is fixed to the base 70.

Further, a ball nut 48 is fixed to the pace 70,
A ball screw 46, which is a transmission means, is screwed into the pole nut 48.

Next, the operation of the injection molding machine of this embodiment will be explained.

First, in the metering and back pressure process of the injection molding machine, the clutch 74 is in the ○N state, and the metering/injection screw 52
are the clutch 74, the spline shaft 60, and the spline gear 6.
8 and the motor 44 via the gear 64.
4 rotates, the metering/injection screw 52 rotates, and the resin is metered. Note that the rotation of the motor 44 is controlled to a specified rotation speed by feeding back a signal obtained by a position detector 50 attached to the motor 44 to a controller (not shown).

When the metering/injection screw 52 rotates to measure the resin for injection molding, the molten resin for injection molding is accumulated in the metering/injection cylinder 54, and the metering/injection screw 52 is caused by the resin pressure of the accumulated molten resin. , clutch 74,
A force acts to move the entire spline shaft 60 and clutch 66 backward.

On the other hand, the motor 42 is attached to the base 70 via a gear box 82, and the clutch 66 is in an OFF state during the weighing and back pressure processes.
62 is separated, so the ball screw 46 is connected to the motor 4.
2 to exert a force that does not cause the aforementioned metering/injection screen -52 to retreat, thereby applying back pressure to the molten resin for injection molding. The rotational force of this motor 42 is
The specified torque is controlled by feeding back a signal obtained by a position detector 40 attached to the motor 42 to a controller (not shown).

Next, in the injection and pressure holding process of the injection molding machine, the molten resin accumulated in the metering and injection cylinder 54 in the above-mentioned metering and backpressure process is preliminarily clamped by moving the metering and injection screw 52 forward. The inside of the mold 59 is filled. At this time, since a backflow prevention ring (not shown) is attached to the tip of the metering/injection screw 52, the metering/injection screw 52 will not be reversed due to backflow caused by the filling pressure of the molten resin.

Therefore, there is no need to rotate the motor 44, which is connected to the metering/injection screw 52 via the clutch 74, spline shaft 60, spline gear 68, and gear 64, to prevent reverse rotation. Since there is no need to control the rotation speed to a specified number by feeding back the signal obtained by the position detector 40 to a controller (not shown), the motor 44 can be controlled out, that is, in a free state.

Now, measurement and injection procedure! In order to advance J5-52 toward the mold 59, the motor 42 is rotated and the gear 76, spline gear 78, spline shaft 62, and coupling 72 1 from the ball nut 48 mounted on the base 70 by rotating the ball screw 46 coupled through the base 70. It is sufficient to apply a force that moves the metering/injection screen 5-52, clutch 74, spline shaft 60, and clutch 66 forward. At this time, since the motor 44 is in a free state, the clutch 66 is set to the N state and the spline shaft 60 is
．． 62 and the rotation of the spline shaft 60 via the gear 64 and spline gear 68 connected to the motor 44 is controlled by the gear 76 connected to the motor 42 and the spline gear 78.
The spline shaft 62 is rotated in synchronization with the rotation of the spline shaft 62 via the spline shaft 62. In this case, the force for advancing the metering and injection valve 'J, -52 is the sum of the rotational force of the motor 42 and the rotational force of the motor 44. Note that the rotation of the motor 42 is caused by a signal obtained by a position detector 40 attached to the motor 42.
The rotation of the motor 44 is controlled by feeding back signals obtained by a position detector 50 attached to the motor 44 to a controller (not shown), so that the rotation speed of the metering/injection spoon 'J5-52 is determined in advance. In other words, control can be performed in accordance with the injection pattern.

In this way, the molten resin for injection molding accumulated in the metering/injection cylinder 54 can be injected into the mold 59 to fill it. Next, the bow continues to apply pressure to the filled molten resin for the purpose of preventing problems such as the like. In other words, a holding pressure is applied. This can be accomplished by rotating the motor 42 and exerting a force that advances the metering and injection screw 52, clutch 74, spline shaft 60, and clutch 66. At this time, if you do the same as in the previous case, you can measure and inject! J:, -5
2. The force that moves the clutch 74, spline shaft 60, and clutch 66 forward is the sum of the rotational force of the motor 42 and the rotational force of the motor 44. The rotation of the motor 42 feeds back a signal obtained by a position detector 40 attached to the motor 42, and the rotation of the motor 44 feeds back a signal obtained from a position detector 50 attached to the motor 44 to a controller (not shown). a predetermined forward pressure cover turn of the metering and injection screw 52;
That is, it is controlled in accordance with the holding pressure pattern.

In addition, as the motors 42 and 44 used in the above example,
It is also possible to configure it using a hydraulic motor.

In the above example, the required motor capacity for each process of metering, back pressure, injection, and pressure holding of the injection molding machine is as follows:
The following can be considered.

Measurement... 7kW Back pressure... 2kW injection...
・1QkW Holding pressure...15kW In this example,
The processes of metering, injection, and pressure holding are performed by one motor 44, and the processes of back pressure, injection, and pressure holding are performed by another motor 42.The capacities of the motors 42 and 44 are selected as follows. Can be set.

Capacity of motor 42 for back pressure, injection, and pressure holding...7.5 kW Capacity of motor 44 for metering, injection, and pressure holding...7.5 kW In addition, when the motor 42.44 is set as above,
The power supply capacity required for motor control power converters is
If it is defined as 0%, the following can be considered.

Total motor power capacity...18.75kW Total power converter power capacity for motor control...23
．． Figure 2 summarizes the above 44kW. Note that the time course is the same as in the case of FIG.

Now, looking at the motor 42.44, the minimum/maximum required capacity...9/15kW installed capacity...
・15kW, and looking at the power converter for motor control, the minimum/maximum required capacity is 11.25/18.75kW and the installed capacity is 18.75kW. As a result, compared to the conventional case, the utilization rate of the equipment is improved from 41/68% to 60/100%, and the equipment capacity can be reduced to about 2/3. Then, we will consider the motor rating in more detail in this case, and also consider gear 64 and spline gear 6.
Considering the gear ratio of 8, the gear 76, and the spline gear 78, the following can be considered based on the above-mentioned contents.

Measuring motor: 7.5kW, 1500rpm Back pressure, injection, pressure holding motor: 7.5kW, 1500rpm Gear ratio between gear 64 and spline gear 68: 4/15 Gear between gear 76 and spline gear 78 Ratio...4/15 As for the range of standard motor ratings, the following can be considered for use in boat fishing.

Rated capacity: 0.5kW to 15kW Rated rotation speed: 11,000 rpm to 3,000 pm or more.If this is done, the types of processes of plastic injection molding machine such as metering, back pressure, injection, and pressure holding. It becomes possible to select a motor from a range of standard motors without being greatly affected by the conditions of the motor, and it is possible to reduce unnecessary costs for products.

[Effects of the Invention] As described above, according to the present invention, the utilization efficiency of equipment can be improved and the manufacturing cost of the product can be reduced.

Moreover, the movable part mechanism can be easily configured.

[Brief explanation of drawings]

FIG. 1(a) is a plan view of the injection drive mechanism according to the present invention, FIG. 1(b) is a side view of the injection drive mechanism according to the present invention, and FIG. 2 is the required power of the injection drive mechanism according to the present invention. FIG. 3(a) is a plan view of a conventional injection drive mechanism, FIG. FIG. 5 is an explanatory diagram of the time course of the required power of the injection drive mechanism. 40.50...Position detector 42.44...Motor 46...Ball screw 52...Measuring/injection screw 54...Measuring/injection cylinder 60.62...Spline shaft 66.74...・・Clutch 70・Base 80.82・・Gear box

Claims (1)

[Claims] (1) A metering/injection screw, first and second driving means for driving the metering/injection screw, first and second spline shafts that are freely displaceable in the axial direction, and the driving side is the first drive. a first gear train connected to the first spline shaft, the driven side of which is in sliding contact with the first spline shaft, and which transmits the driving force of the first drive means to the first spline shaft; a second gear train connected to the drive means, whose driven side is in sliding contact with the second spline shaft, and transmits the driving force of the second drive means to the second spline shaft; and the metering/injection screw. and the first spline shaft as necessary, and a first transmission means for transmitting the rotational driving force of the first spline shaft to the metering/injection screw; a second transmission means connected to a second spline shaft as necessary to transmit rotational driving force of the second spline shaft to the first spline shaft; , based on the rotational driving force of the second spline shaft, the metering/injection screw is actuated via the first spline shaft, the second transmission means, the second spline shaft, and the first transmission means. An injection drive mechanism characterized by comprising: a displacement means for displacing;