JPH01209118A - Injection molding machine - Google Patents

Abstract

PURPOSE:To shorten the molding cycle time of a product by enhancing followability and increasing the operation speed of a movable part, by driving the fluid actuator of a product recovery apparatus, by the fluid cylinder stretched between a fixed part and the movable part. CONSTITUTION:A movable part 3 is alternately reciprocated in the directions shown by arrows Y1, Y2 and a product 5 is subjected to injection molding at each time when a mold 1 is clamped. After the molding of the product 5, when movable part 3 is moved in the direction shown by the arrow Y2, the piston rod 15a of the second hydraulic cylinder 5 is moved to the right and operation oil is discharged from the first port 15c to be supplied to the first port 14c of the first hydraulic cylinder 14 through a pipeline 15 to drive the first hydraulic cylinder 14. Since the process volume of the first hydraulic cylinder 14 is smaller than that of the second hydraulic cylinder 15, the first hydraulic cylinder 14 is subjected to full stroke operation before the spaced- apart operation of the movable part 3 is completed and a bucket 13 is also moved to a receiving position before the spaced-apart operation of the movable part 13 is completed and the product 5 is demolded with the completion of the spaced-apart operation of the movable part 3 to be recovered in the bucket 13.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an injection molding machine for injection molding resin molded products such as cassette halves, and more specifically, to a product recovery method for recovering products released from the mold when the mold is separated. The present invention relates to an injection molding machine equipped with a device.

[Prior Art] An injection molding machine for injection molding resin molded products such as cassette halves brings together a pair of molds each having a cavity formed in a desired product shape in advance, and then pours molten resin into the cavity. The product is molded by injection.

By the way, such injection molding machines have conventionally been provided with a product recovery device for recovering the product released from the mold when the mold is separated. An injection molding machine equipped with a product recovery device will be explained below.

The injection molding machine shown in FIG. 2 includes a fixed part 2 to which one mold 1a of a pair of molds 1 disposed facing each other is attached, and a mold 1b of the other of the pair of molds l. It consists of an attached movable part 3 and a product recovery device 4.

The opposing surfaces of the pair of molds 1 are formed in a desired shape, so that when they are brought into close contact with each other, a cavity having the same shape as the product 5 is formed at the joint portion. Further, an injection device (not shown) is provided inside the fixing part 2, and is capable of injecting molten resin into the cavity. Moreover, the movable part 3 is provided so as to be able to reciprocate in the directions of arrows Yl and Y2, and moves the other mold 1b to the one mold 1a.
It is designed to be placed in close contact with and separated from the
That is, the limit switch 6 detects whether it is located in the separated position or the close position.

On the other hand, the product recovery device 4 includes a hydraulic cylinder 7 and a packet 8 connected to a piston rod 7a of the hydraulic cylinder 7. The hydraulic cylinder 7 is connected to a hydraulic pump 10 via a conduit 9. A solenoid valve 11 is provided in the conduit 9 to direct the flow of hydraulic oil supplied from the hydraulic pump IO to the close contact of the mold worker.
By switching in conjunction with the separation operation, the packet 8 is moved following the operation of the movable section 3. That is, the solenoid valve 11 is
It is designed to be switched based on the signal from the limit switch 6, and when the movable part 3 is in the separated position,
When a coil (not shown) is excited and switched to the position (left side position in the figure) for supplying hydraulic oil to the first port 7b of the hydraulic cylinder 7, and the movable part 3 is in the close contact position, the coil excitation is stopped and the 2 ports) 7c (on the right side in the figure). Therefore, mold 1
When separated, the packet 8 is moved to the receiving position below the pair of molds 1, and when the molds 1 are brought into close contact, the packet 8 is moved to a standby position where it is retreated from below the mold 1.

In the injection molding machine having the above configuration, the movable part 3 is alternately moved in the directions of arrows Y1 and Y2, and the pair of molds 1 are repeatedly brought into close contact with each other and separated, and each time the molds 1 are brought into close contact with each other. Molten resin is injected by an injection device (not shown) to mold the product 5. The product 5 molded in this way is released from the mold as the mold 1 is separated and falls downward, and the receiver is placed in the packet 8 which is moved to the receiving position in conjunction with the separating operation of the mold I. It is then taken out one by one to the outside of the injection molding machine.

[Problem to be Solved by the Invention] Incidentally, in the conventional injection molding machine described above, many attempts have been made to speed up the operation of the movable part 3 and shorten the cycle time for molding the product 5. but,
The fluid actuator that drives the product recovery device 4, that is, the followability of the hydraulic cylinder 7 is a problem, and there is a drawback that it is not possible to increase the speed as desired.

That is, since the hydraulic cylinder 7 is driven by the exchange of electrical signals between the limit switch 6 and the solenoid valve 11, in order to increase the speed, it is necessary to move the operating position of the limit switch 6 closer to the mold 1 close position, and to It is required to shorten the time from when the mold l separation signal is obtained in step 6 until the solenoid valve 11 is actually driven, that is, the operating time. However, in reality, the limit switch 6 and solenoid valve 11
Considering the delay in the operation of the mold I and the fact that the packet 8 must be reliably in the standby position when the mold I is in close contact with the mold I, it is necessary to check the operation timing of the hydraulic cylinder 7 and the limit switch 6 to confirm that the mold 1 is sufficiently separated. It has to be set to be driven after confirmation, and as a result, wasted time occurs between when the mold 1 is separated and when the packet 8 is moved to the receiving position.

In addition, since switching of the drive direction of the hydraulic cylinder 7 depends on the solenoid valve 11, the risk of malfunction of the solenoid valve 11 cannot be completely eliminated, and reliability is lacking even when the speed of the movable part 3 is increased. It also had some drawbacks, and this was one of the factors that hindered speeding up.

In addition, even if the drive timing of the limit switch 6 and solenoid valve 11 is actually increased to the allowable limit, it takes about 3 seconds from when the mold 1 is separated until the packet 8 takes out the product 5. If the speed was increased further than this, the movement of the packet 8 would not be able to follow the movement of the movable part 3, which would be dangerous.

The present invention was made against this background, and provides a fluid actuator that drives a product recovery device and an injection molding machine that is linked to the operation of a movable part without depending on the exchange of electrical signals. The purpose is to shorten the cycle time for molding products.

[Means for Solving the Problems] In order to solve the above problems, the present invention bridges a fluid cylinder between a movable part and a fixed part to which respective molds are attached, and connects a port of this fluid cylinder to a product. It is characterized in that it is connected to a port of a fluid actuator that drives the recovery device.

[Function] According to the above configuration, the fluid cylinder is operated in response to the movement of the movable part into close contact or separation, and the working fluid in the fluid cylinder is supplied to the fluid actuator in conjunction with the movement of the movable part. Therefore, the fluid actuator is reliably driven in accordance with the movement of the movable part, and the product recovery device is operated in conjunction with the movement of the movable part.

[Example] The present invention will be described in detail below with reference to FIG. Note that the same components as those of the conventional injection molding machine described above are given the same reference numerals to simplify the explanation thereof.

As shown in FIG. 1, the injection molding machine of this embodiment includes a fixed part 2 to which one mold 1a of a pair of molds 1 is installed facing each other, and a fixed part 2 to which one mold 1a of a pair of molds 1 is installed, and The movable part 3 to which the other mold 1b of 1 is attached, and the product recovery device 1
It is composed of 2.

The product recovery device 12 is provided to recover the product 5 that is released when the mold l is separated, and includes a packet 13 that receives and takes the product 5, and a first device that drives the packet 13.
, and a second hydraulic cylinder 15 spanned between the fixed part 2 and the movable part 3.

The first hydraulic cylinder I4 has a piston area 14a.
The tip of the cylinder tube +4b is fixed to the packet 13, and the cylinder tube +4b is fixed to the device body (not shown), and the reciprocating movement of the piston rod 14a moves the packet 13 between the receiving position below the mold l and the standby position. It is designed to allow On the other hand, the second hydraulic cylinder 15
The piston rod 15a is fixed to the movable part 3, and the cylinder tube 15b is fixed to the fixed part 2, so that it is bridged between the fixed part 2 and the movable part 3, and the movable part 3 The reciprocating movement of the piston rod 15a causes the piston rod 15a to relatively reciprocate within the cylinder tube 15b. And the first,
The second hydraulic cylinder 14.15 has a first port 14c,
The piston rods 14a and 15a are directly connected by a conduit 16 connecting the second ports 15c and a conduit 17 connecting the second ports 14d and 15d, and the piston rods 14a and 15a are interlocked by the hydraulic oil sealed inside each. There is. Also,
The stroke volume determined by the product of the stroke amount and the piston area of the second hydraulic cylinder 15 is determined to be sufficiently larger than the stroke volume of the first hydraulic cylinder 14 .

Further, each of the pipe lines 16 and 17 has a relief valve 1.
8 and a check valve 19 to a tank 20 . The relief valve 18 is provided to maintain the hydraulic pressure in the pipes 16 and 17 below a certain value, and when the hydraulic pressure in each pipe 16 and I7 rises above a predetermined pressure, Excess hydraulic oil is discharged into the tank 20 to prevent pressure from increasing. The set pressure of each relief valve 18 is set to about the pressure required to operate a general hydraulic cylinder (for example, 35 kg/cm''). This is provided to replenish the hydraulic oil in tank 20.
It is arranged in an orientation that allows hydraulic oil to flow in one direction from the hydraulic cylinder I4.15 to each hydraulic cylinder I4.15.

The pipe line 16.17 further includes a flow rate regulating valve 21.
and a cooler 22 are provided. The flow rate adjustment valve 21
is from the second hydraulic cylinder 15 to the first hydraulic cylinder 1
This is for adjusting the operating speed of the first hydraulic cylinder 14 by adjusting the flow rate of the hydraulic oil flowing to the first hydraulic cylinder 14 . Further, the cooler 22 cools the hydraulic oil flowing inside the pipe line 16.17 with cooling water, and cools the hydraulic oil flowing inside the pipe line 16.17 to cool each hydraulic cylinder 14.15.
This prevents the temperature of the hydraulic oil flowing back and forth from rising.

In the injection molding machine having the above configuration, the movable part 3 is alternately reciprocated in the directions of arrows Y1 and Y2, and the product 5 is injection molded each time the mold 1 is brought into close contact with the movable part 3. and,
The product 5 molded in this way is released when the mold 1 is separated and falls below the mold 1, but at this time, the packet 13 of the product recovery device 12 moves it below the mold 1. Therefore, the product is collected in the packet 13 and collected.The operation of the product collection device 12 will be described in detail below.

After molding the product 5, when the movable part 3 starts moving in the direction of arrow Y2, the piston rod 15a of the second hydraulic cylinder 15 is moved to the right in the figure due to this movement, so that it is activated from the first port 15c. Oil is drained. The pressure of the hydraulic oil discharged in this way reaches the relief valve 18.
Since the pressure is lower than the set pressure, the pressure is supplied to the first port 14c of the first hydraulic cylinder I4 through the conduit 16, thereby driving the first hydraulic cylinder 14. As described above, since the stroke volume of the first hydraulic cylinder 14 is smaller than the stroke volume of the second hydraulic cylinder 15, the first hydraulic cylinder 14 is operated to a full stroke before the separation operation of the movable part 3 is completed. , Therefore, the packet 13 is also connected to the movable part 3.
The receiver is moved to the receiving position before the separating operation is completed.

After the product 5 is released from the mold and collected in the packet 13 upon completion of the separation operation of the movable part 3, the movable part 3 is moved to the mold I.
When the piston rod 15a of the second hydraulic cylinder 15 starts to move in the direction of the arrow Y1 in order to bring the two into close contact with each other, the piston rod 15a of the second hydraulic cylinder 15 is operated in the opposite direction to when the two are separated, and hydraulic oil is discharged from the second port 15d.

This hydraulic oil is then supplied to the second port 14d of the first hydraulic cylinder I4 via the conduit 17, thereby driving the first hydraulic cylinder 14 in the opposite direction. Then, as in the case of separation, the packet 1 is
3 is completely retracted to the standby position.

By the way, during the above operation, from the completion of the operation of the packet 13 to the completion of the operation of the movable part 3, the hydraulic oil continues to be supplied from the second hydraulic cylinder 15 by the stroke volume difference of each hydraulic cylinder I4.15. The pressure inside the pipe line 16 or 17 increases due to the discharge, but the relief valve 18 is opened in conjunction with this pressure increase, and the excess hydraulic oil is drained into the tank 20.
Therefore, the pressure in the pipe 16 or 17 is maintained at a value below the set value. In addition, the second hydraulic cylinder 1
At the same time as the hydraulic oil is discharged from the contraction side of the first hydraulic cylinder 14, the expansion side, that is, the side from which the hydraulic oil is sucked, sucks the hydraulic oil discharged from the contraction side of the first hydraulic cylinder 14. The amount of hydraulic fluid stored in each hydraulic cylinder 14.1
It is conceivable that there is a shortage of 5 stroke volume differences. However, this shortfall of 12- is caused by the check valve 19 opening due to the generation of negative pressure due to the expansion of the volume on the expansion side of the second hydraulic cylinder 15 after the supply of hydraulic oil from the first hydraulic cylinder 14 is completed. Karate Tank 20
Each hydraulic cylinder 14.1
There is no shortage of hydraulic oil in 5.

As explained above, in the injection molding machine of this embodiment, the first hydraulic cylinder 14 drives the packet 13 of the product recovery device 12, and the second hydraulic cylinder spans between the fixed part 2 and the movable part 3. The packet 13 is driven by the hydraulic cylinder 15 of the
is moved reliably, and there is no need to move the packet 13 by exchanging electrical signals between limit switches and solenoid valves one by one as in conventional injection molding machines. In addition, switching the drive direction of the first hydraulic cylinder 14 does not require electrical control using a solenoid valve or the like, and therefore the risk of malfunction at higher speeds is significantly reduced. For this reason, the followability and reliability of the packet 13 movement are greatly improved, the drawbacks of increasing the speed of the moving part 3 movement are eliminated, and the cycle time of product 5 molding is significantly shortened. .

In addition, since the second hydraulic cylinder 15 is used as the drive source for the first hydraulic cylinder I4, an expensive hydraulic pump can be eliminated, which can also be expected to reduce the cost of the injection molding machine. be.

In this embodiment, a hydraulic cylinder is used as the fluid actuator for driving the packet 13, but the present invention is not limited thereto. For example, the packet 13 can be easily driven by a rotary actuator or by a plurality of fluid actuators. Furthermore, the configuration of the product recovery device 12 is not limited to the one in which the product 5 is received and taken by the packet 13, but may be of a type that grips the product 5 using hydraulic pressure, etc. Any device that can be operated by switching the fluid flow direction accordingly can be easily applied. Further, the working fluid is not limited to hydraulic pressure, and may be operated by high-pressure air.

[Effect of the Invention J As explained above, in this invention, the fluid actuator of the product recovery device is driven by the fluid cylinder spanned between the fixed part and the movable part, so the product recovery device can be electrically operated. Close contact of moving parts without exchanging signals,
It can be reliably linked with the separation operation, and its followability is greatly improved, as well as its reliability. Therefore, it is possible to speed up the operation of the movable part and shorten the cycle time for molding the product, and the effect is remarkable. Furthermore, since there is no need to use an expensive power generation source as a drive source for driving the fluid actuator, it is possible to expect the effect of reducing the cost of the machine.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the arrangement of the eleventh and second hydraulic cylinders and the configuration of the hydraulic circuit connecting each hydraulic cylinder in an embodiment of the present invention, and FIG. 2 shows the configuration and hydraulic circuit of a conventional injection molding machine. It is an explanatory diagram. l...Pair of molds, 1a...One mold, I
b...Other mold, 2. Fixed part, 3... Movable part, 12... Product recovery device, 14... First hydraulic cylinder (fluid actuator), 15...・Second
Hydraulic cylinder (fluid cylinder).

Claims (1)

[Claims] a fixed part to which one of a pair of molds provided facing each other is attached; and a movable part to which the other of the pair of molds is attached, and which moves the other mold into close contact with the one mold. and a product recovery device driven by a fluid actuator, the product is molded by injecting molten resin into a pair of molds that are brought into close contact with each other by the operation of the movable part, and then the product is molded into the other mold. In an injection molding machine in which the mold is separated and the fluid actuator is operated to recover the product by the product recovery device, a fluid cylinder is bridged between the movable part and the fixed part, and the fluid cylinder is An injection molding machine, characterized in that a port is connected to a port of the fluid actuator of the product recovery device.