JPH0872089A - Resin supplying apparatus for injection molding - Google Patents

Abstract

PURPOSE: To prevent the heap-up of resin at the end of a plunger when resin is cast in molds via a resin supply hole in an indexing table by the plunger from below the table and the plunger is separated from the table in the injection molding by indexing a plurality of the molds by an indexing unit. CONSTITUTION: A plunger 16 is formed in a piston state, and a pressure release hole 24b is brought into coincidence with a resin inlet 16c at its lowered position. A shutter 26 is provided. When the shutter 26 is closed, a shutter hole 26c is opened to diffuse the air to the hole 26c. Thus, the resin in the resin supply passage 16b of the plunger 16 released from its pressurized state is moved from the resin inlet 16c to the hole 24b, and the heap-up of the resin to the plunger end 16a is eliminated. Since there is the shutter 26, the resin is not transferred to the plunger end 16a at the start of lowering of the shutter 26.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin supply device for an injection molding machine which indexes a plurality of injection molding dies to an indexing position and supplies resin at the indexing position.

[0002]

2. Description of the Related Art FIG. 4 shows a rotary table in which a plurality of molds are indexed to respective indexing positions and resin is supplied at the indexing positions. In FIG. 4, a shaft 3 for rotational indexing is rotatably supported by a bearing base 2 fixed to a base 1, and a disc-shaped table 4 is fixed to the shaft 3. The table 4 is also supported by rollers 6 rotatably mounted on a stand 5 standing on the base 1. The axis of the roller 6 faces the radial direction of the table 4. The indexing rotation of the table 4 is as shown in FIG.
Is performed by a drive roller 7 or a pinion that is pressed against
The die 9 on the table 4 is positioned at the indexing position D by the indexing pin 8 that goes in and out of the indexing hole in the radial direction provided on the peripheral surface of the table 4.

Therefore, like the ordinary indexing table, the table 4 is rotated by a predetermined angle by the drive roller 7 in a state where the indexing pin 8 is retracted, and when the indexing is detected by the detecting means (not shown), the indexing pin 8 is indexed on the table 4. It rushes into a hole.

In this example, the molds 9 are mounted on the table 4 in a manner that the molds 6 are equally arranged, and the pedestal 12 provided on the column 11 fixed to the base 1 at the indexing position D supports the lower surface of the table 4. In the figure, an arrow a shown above the pedestal 12 is provided.
The die 9 is pressed and fixed by the ram 13 hydraulically driven in the vertical direction. To give an overview of the resin supply, the shutter 18 is opened, and the molten resin from a not-shown ruder is injected from the resin injection port 14a and is supplied through the resin supply passage 14b to the resin supply hole 4a provided in the table 4. It is adapted to be supplied to the mold 9 through a resin supply hole 4a which is a through hole provided in the table 4 through a subsequent resin supply passage.

[0005]

FIG. 6 shows the above-mentioned FIG. 4 and FIG.
It is a longitudinal cross-sectional view which shows the detail of the conventional example of the table in the indexing position shown in FIG.

The plunger 116 is movable in the vertical direction by a driving device such as a fluid pressure cylinder 17, and as shown in the figure, the conical recess 21a of the resin receiving member 21 and the plunger tip 116.
The upper end position where a is fitted and the position away from the concave portion 21a are taken. A resin supply passage 116b is provided in the plunger 116, and the end surface having the resin receiving port 116c slides on the shutter 19. Is designed to move,
At the upper limit position of the plunger 116, the resin receiving port 116c
Is the same as the shutter hole 19a of the shutter 19 and passes through the resin supply passage 14b communicating with the ruder, and the resin is supplied through the resin supply passage 116b of the plunger 116 through the through hole 21b of the resin receiving member 21 and the resin supply of the table 4. It is injected into the mold 9 through the hole 4a, and after the injection, first the resin injection port 14
After the shutter 18 on the a side (see FIG. 4) is closed and the resin supply passage 14b from the rudder is shut off, the plunger 116 is lowered.

After the plunger 116 descends, the ram 13 rises to release the fixation of the mold 9 at the indexing position, the table 14 rotates for indexing, and a new resin-uninjected mold 9 rotates to the indexing position D. The ram 13 is lowered and fixed. Here, the plunger 116 rises and the tip 116a fits into the recess 21a of the resin receiving member 21, and then the shutter 18 opens and the resin receiving passage 116b of the rudder, the resin supply passage 14b and the plunger 16 becomes the shutter hole 19.
The resin is injected into the mold 9 again via the a.

By repeating the process as described above, the dies 9 successively come to the indexing position to inject the resin, and cooling and demolding are performed outside the indexing position to take out the product.

In the above, the tip 11 of the plunger 116 is
The resin supply passage 116b of the plunger 116 is filled with the pressurized resin in a state in which the resin 6a is fitted in the recess 21a of the resin inlet / outlet member 21. Plunger 11 in this state
When 6 is lowered, the pressure applied to the resin, which has been maintained by the tip 116a of the plunger coming into close contact with the recess 21a of the resin receiving member 21, is released, so that the resin in the resin supply passage 116b of the plunger expands. And plunger 116
For example, about 5 mm rises at the center of the tip end 116a of the plunger 116 and spreads to the surface of the tip end 116a of the plunger 116 that should come into contact with the recess 21a of the resin inlet / outlet member 21.

When the plunger 116 rises and the tip 116a of the resin bulges in the center of the tip 116a of the plunger 116 fits into the recess 21a of the resin receiving member 21, the plunger tip 116a and the recess 21a of the resin receiving member 21 are separated from each other. If this is repeated, the sealing will be incomplete due to the gap between the plunger tip 116a and the recess 21a of the resin receiving member 21, and the resin will leak so that the resin can no longer be injected.

To solve this problem, a vertical space is provided in the plunger, a downward valve seat is provided in the tip of the plunger, and a needle valve for opening and closing the valve seat is provided in the plunger. There is one in which a drive device is provided so as to take a position where the seat is closed and a position where the seat is opened. However, if a needle is provided in this plunger and a device for driving the needle in the vertical direction is provided, it is a countermeasure against the resin rising from the tip of the plunger after the resin is injected into the mold as described above.

However, if this is done, (1) the needle and its driving means, the confirmation means for controlling the needle, the cartridge heater for keeping the temperature of the plunger, etc., must be incorporated in the plunger, and the device is complicated and extremely complicated. It becomes expensive. (2) If there is a problem with the movement of the needle inside, resin is inside and maintenance is difficult. (3) The control is complicated because the opening / closing of the needle and the vertical movement of the plunger are controlled independently of each other. There are problems such as.

Further, in the above conventional example, the resin receiving member 2
1 has a through hole 2b and the table 4 has a resin supply hole 4a,
The plunger 116 is retracted to move the recess 2 of the resin receiving member 21.
Through hole 21b of resin receiving member 21 when separated from 1a
The lower resin transfers to the tip 116a of the plunger 116 and rises to the tip 116a of the plunger 116 to adhere the resin, which spreads at the tip 116a of the plunger 116 and the resin supply path 116b of the plunger 116 described above.
Is free of pressure, the tip 116 of the plunger 116 is
Plunger 116 together with resin that swells to a and rises
A large bulge is formed on the tip 116a of the resin, and it is sandwiched between the recesses 21a of the resin receiving member 21 and the injection molding cannot be continued.

It is an object of the present invention to solve the above-mentioned drawbacks of the conventional resin supply device for an injection molding machine, and to provide a resin supply device for an injection molding machine, which has no resin swelling from the tip of the plunger and has a simple structure and operates reliably. And

[0015]

A first aspect of the present invention is a resin which allows a plurality of molds and a mold to be mounted on the upper side, and which vertically penetrates at the position where the molds are mounted so as to communicate with the molds. An indexing table that is provided with each supply hole and indexes the die to the resin supply position, an upper position that communicates with the resin supply hole of the table under the table at the indexing position, and a lower position apart from the resin supply hole of the table. In the injection-molding resin supply device including a vertically movable member having a resin supply passage that can communicate with the resin supply hole of the table, the vertically movable member is a plunger that slides vertically in the housing. , The plunger is provided with a resin supply path downward from the upper end and a resin receiving opening that communicates the resin supply path with the outer periphery of the plunger, and the housing is provided with a resin supply opening that communicates with the resin extruder. The injection is characterized in that the resin receiving port of the plunger coincides with the resin supplying port of the housing at a position where the plunger rises and communicates with the resin supplying hole under the table, and the resin receiving port is opened at the position where the plunger descends. It is a molding resin supply device.

According to a second aspect of the present invention, a shutter having a vertical through hole through which resin passes is interposed between the tip of the plunger and the table, and the resin supply hole of the plunger and the table and the through hole of the shutter coincide with each other. The resin supply device for injection molding according to the first aspect of the invention is characterized in that a drive means is provided that takes a position where the shutter is opened and a position where the through hole of the shutter is opened.

A third invention of the present invention is for injection molding according to the second invention, characterized in that a blowout port for blowing compressed air into the through hole is provided at a position where the through hole of the shutter is opened. It is a resin supply device.

A fourth invention of the present invention is the injection-molding resin supply apparatus according to the second or third invention, wherein the through hole of the shutter is a downwardly expanding tapered hole.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

The table, the table indexing device, the mold fixing device at the indexing position, and the like described with reference to FIGS. 4 and 5 are the same in this embodiment, and therefore the repetitive description will be omitted. The portions that best represent the different features of the present invention will be described.

FIG. 1 is a radial vertical sectional view through the indexing position of the table.

An upper base 23 is further fixed to the lower base 22 provided on the base 1. A fluid pressure cylinder 17, which is a hydraulic cylinder in this example, is fixed to the lower frame 23a of the upper table 23 on a vertical axis passing through the indexing position D (see FIG. 5). The piston rod 17a of the fluid pressure cylinder 17 is coaxial with the fluid pressure cylinder 17, and the plunger 16 is fixed via a joint 30.

The plunger 16 has a cylindrical shape and the tip 16a has a conical shape. A resin supply passage 16b is provided downward from the center of the tip 16a, and a resin receiving port 16c is provided from the bottom of the resin supply passage 16b in the radial direction. Has been. The plunger 16 is fitted in the housing 24 so as to slide in the vertical direction.

The housing 24 is fixed to the upper frame 23b of the upper table 23 described above, and has a resin supply port 24a at a position corresponding to the resin receiving port 16c of the plunger 16 at the upper limit position of the plunger 16 and the plunger 16 The pressure release hole 24b is formed at the lower limit position of the pressure matching position with the resin receiving port 16b of the plunger 16. The pressure release hole 24b is open to the outside.

The shutter guide 25 having a conical recess 25a into which the tip 16a of the plunger 16 fits when the plunger 16 moves up is formed by a member (not shown) for the column 1.
1 is carried. A guide 25b is provided in the shutter guide 25 in the left-right direction in FIG. 1, and a shutter 26 is movably fitted in the guide 25b. Shutter guide 2
5. The shutter 26 has a shutter guide hole 25c for communicating the resin supply hole 4a of the table 4 with the resin supply passage 16b of the plunger 16, and a shutter hole 26 having a downwardly expanded tapered hole.
c is provided. A drive connection hole 26b is provided in the base 26a of the shutter 26. The shutter guide 25
The conical recess 25a provided in the
When the 6a is fitted, the conical recess 25a and the plunger 16
The conical portion of the tip 16a of the plunger 16 is in close contact with the top surface of the tip 16a of the plunger 16 and reaches the shutter 26.

A horizontal driving device provided on a stand 27 standing upright on the base 1, for example, a piston 29a of a fluid pressure cylinder 28 has a connecting member 29 fixed to the end of the piston connecting rod 26b. The connector 29 is supported by a fixed slide guide 31.

FIG. 2 is an enlarged sectional view of the portion A in FIG. When the shutter 26 moves to the left, the shutter guide 25 is provided with a relief hole 25d for a downwardly expanding tapered hole that coincides with the shutter hole 26c at the leftmost limit position.
A compressed air blowing port 25e is provided on the opposite side of the shutter 26 with the shutter 26 in between. Shutter hole 26c
The escape hole 25d and the escape hole 25d form one tapered hole.

The outlet 25e communicates with a compressed air source such as an air compressor 33. The escape hole 25d is provided with a container (not shown) that is removed from the shutter hole 26c via a chute or the like to contain the resin.

In the above-mentioned members, through which resin passes, that is, the housing 24, the plunger 16, the shutter guide 25, the members constituting the resin supply hole 4a of the table 4, etc., the electric resistance wire heat is generated so that the resin does not solidify. A cartridge heater having a body is provided by being embedded or the like.
The band heater 4c is embedded in or surrounded by the tubular member 4b forming the resin supply hole 4a of the table 4, and the band heater 4c is always energized, and the resin in the resin supply hole 4a is in a molten state. Is.

The operation of the above configuration will be described with reference to FIG.
In FIG. 3A, the resin injection into the mold 9 is completed, the table 4 is in the indexing rotation, the shutter 26 moves to the left, and the shutter hole 26c is the escape hole 25d of the shutter guide 25.
The plunger 16 is lowered and the resin receiving port 16c of the plunger 16 is moved to the pressure release hole 24b of the housing 24.
Is consistent with In the state shown in the drawing, compressed air is blown out from the air blowout port 25e, and the resin that easily hardens in the shutter hole 26c of the shutter 26, which is difficult to keep warm, is pushed to release the compressed air.
It is discharged from d and stored in a container (not shown). On the other hand, the pressure of the resin in the resin supply passage 16b of the plunger 16 is released, and the weight of the resin causes the resin to move downward in the resin supply passage 16b to the resin receiving port 16c and the pressure release hole 24b side. As a result, the resin does not rise from the resin supply passage 16b to the plunger tip 16a and does not rise, but conversely, at the outlet of the resin supply passage 16b, the resin becomes flat or dented in line with the outlet. Since the resin injection is as short as about 1 minute and the indexing time of the table 4 is also short, the resin injection time shown in FIG.
Is a short time, the plunger 16 moves to the ascending position from the lower limit position, while the indexing of the table 4 is completed and the unfilled mold 9 is rotated to the indexing position and positioned. Fixed by.

When the plunger 16 rises as shown in FIG. 3B, the resin receiving hole 16c of the plunger 16 is disengaged from the pressure release hole 24b of the housing, and the tip 16a of the plunger 16 is pressed against the recess 25a of the shutter guide 25 and the plunger 16 is pressed. The resin receiving port 16c of the housing 2 is
4 corresponds to the resin supply port 24a. Here, the shutter 18 of the injection port 14a connected to the ruder is opened, and the housing 24 is passed through the resin injection port 14a and the resin supply path 14b.
From the resin supply port 24a to the resin receiving port 1 of the plunger 16
Since the pressure is applied to 6c and the shutter 26 is closed, the resin in the resin supply passage 16b of the plunger 16 is pressurized but does not flow.

As shown in FIG. 3C, the fluid pressure cylinder 28 is now urged so that its piston rod 28a is pushed out, and the connector 29 pushes the base 26a of the shutter 26,
The shutter 26 is moved rightward in the shutter guide 25, and the shutter hole 26c is aligned with the shutter guide hole 25c.
Is injected into the mold 9 through the resin supply hole 4a of the table 4.

As shown in FIG. 3D, when the injection of the resin into the mold 9 is completed, the shutter 26 moves to the left because the fluid pressure cylinder 28 is urged in the direction opposite to the above, and the shutter guide hole 25c is closed and the shutter guide hole 25c is closed. The resin sent is also blocked by the shutter 18. Subsequently, the plunger 16 is urged downward and descends, and the tip 16a of the plunger 16 separates from the recess 25a of the shutter guide 25. The resin receiving port 16c of the plunger 16 is removed from the resin supply port 24a of the housing 24. Since the upper end of the resin supply passage 16c of the plunger 16 is open and the resin receiving port 16c side is closed, the resin in the resin supply passage 16b of the plunger 16 starts to expand upward. However, when the plunger 16 reaches the lower limit position,
As shown in FIG. 3A, the resin receiving port 16c of the plunger 16 coincides with the pressure release hole 24b of the housing 24. Here, the resin in the resin supply path 16b of the plunger 16 descends due to its gravity and moves from the resin receiving port 16c toward the pressure release hole 24b. In such an operation, since the plunger 16 is in the lower limit position in FIG. 3A for a short time, a small amount of resin moves only from the resin receiving port 16c of the plunger into the pressure release hole 24b of the housing 24. This prevents the resin from bulging to the tip 16a of the plunger 16.

As a result of the above, it is possible that the conventional thick-walled injection molding could not use the rotary table because it was difficult to inject, so that a large injection molding machine was not required, and a load of about 30 kg / cm ^{2 was applied.} It can be molded by pressure and the production efficiency is improved.

Although the embodiment has been described with respect to the rotary indexing table, the same applies to the case where the table moves linearly and linear indexing is possible.

[0036]

According to the first aspect of the present invention, a plunger provided with a resin supply passage communicating with the resin supply hole of the table and a resin supply hole of the housing is provided just below the indexing position of the die when the plunger is raised. Since both ends of the resin supply path are opened at the lowered position of the plunger, resin swelling at the tip of the plunger when the plunger is retracted is prevented, and the maintenance of the injection molding resin supply device using the indexing table is easy. Play. Moreover, the device has a simple structure in which the plunger is moved up and down and is inexpensive.

In the second invention of the present invention, since the shutter is interposed between the table and the piston in the first invention,
It is possible to prevent resin from adhering to the tip of the piston when the piston moves backward from the resin supply hole on the table side.

In the third invention of the present invention, when the shutter is closed in the second invention, the compressed air is blown into the through hole of the shutter. Therefore, it is easy to fix the resin to the through hole of the shutter. Can be removed.

According to the fourth aspect of the present invention, in the second or third aspect of the invention, the through hole of the shutter is formed as a downwardly expanding tapered hole. Therefore, the resin remaining in the through hole easily flows down naturally, and Even if it solidifies, it can be easily removed with compressed air.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is an enlarged vertical sectional view showing a part of FIG.

3A, 3B, 3C and 3D are vertical sectional views showing the operation of the embodiment of the present invention.

FIG. 4 is a side view of a rotary indexing table for injection molding.

FIG. 5 is a plan view of FIG.

FIG. 6 is a vertical sectional view of a conventional example.

[Explanation of symbols]

 16 Plunger 16a Plunger tip 16b Resin supply path 16c Receptacle inlet 24 Housing 24a Resin supply port 24b Pressure release hole 25 Shutter guide 25c Guide hole 26 Shutter 26c Shutter hole

Claims (4)

[Claims] 1. A mold to a resin supply position, wherein a plurality of molds and a mold can be mounted on the upper side, and resin mold holes are provided, which penetrate vertically at the position where the molds are mounted and communicate with the mold, respectively. Taking an indexing table for indexing, an upper position communicating with the resin supply hole of the table under the table at the indexing position, and a lower position apart from the resin supply hole of the table,
In an injection molding resin supply device including a vertically movable member having a resin supply passage that can communicate with the resin supply hole of the table, the vertically movable member is a plunger that slides vertically in a housing, Is provided with a resin supply path downward from the upper end and a resin receiving opening that communicates the resin supply path with the outer circumference of the plunger, and the housing is provided with a resin supply opening that communicates with the resin extruder. A resin supply device for injection molding, wherein the resin receiving port of the plunger is aligned with the resin supplying port of the housing at a position communicating with the resin supplying hole, and the resin receiving port is opened at a position where the plunger is lowered. 2. A shutter having a vertical through hole through which resin passes is interposed between the tip of the plunger and the table, and the position where the resin supply hole of the plunger and the table and the through hole of the shutter coincide with each other and the through hole of the shutter. The resin supply device for injection molding according to claim 1, further comprising a shutter driving unit that is located at a position where the hole is opened. 3. The position where the through hole of the shutter is opened,
The injection-molding resin supply device according to claim 2, wherein a blowout port for blowing compressed air is provided in the through hole. 4. The injection-molding resin supply device according to claim 2, wherein the through hole of the shutter is a taper hole with a downward expansion.