JPH08230000A - Preplasticizing injection device - Google Patents

Abstract

PURPOSE: To prevent a resin plasticized by a plasticizing cylinder from remaining as a residual by making the temperature of the resin uniform in a resin runner and also providing the resin runner and an inflow pathway obliquely. CONSTITUTION: A plasticizing cylinder 22 is installed side by side with an injection cylinder incorporating a plunger 10. The injection cylinder 12 and the plasticizing cylinder 22 are connected to communicate with each other, using a fine tube 30 as a resin runner 3 installed obliquely at a sharp angle in a forward direction, across a stretch from an inflow pathway in a part corresponding to the forward limits of the plunger at the tip of the injection cylinder to an outflow pathway at the tip of the plasticizing cylinder. The inflow pathway 15 is formed obliquely toward the inner peripheral surface of the injection cylinder 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pre-plastic injection device used for injection molding of synthetic resin.

[0002]

2. Description of the Related Art Generally, in a pre-plastic injection device, a plasticizing cylinder having a screw is provided in parallel with an injection cylinder having a plunger, and the tip of the plasticizing cylinder is an injection cylinder through a large-diameter and short cylinder. Of the resin that is melted and kneaded in the plasticizing cylinder (hereinafter referred to as plasticizing) is connected to the tip of the injection tube and uses the cylinder as a resin path, and then the injection is performed by advancing the plunger. Consist of the composition.

The reason why the resin passage is constituted by a large-diameter and short cylinder or the like is that the flow resistance of the molten resin sent from the plasticizing cylinder in the resin passage is reduced and the resin is injected into the injection cylinder as soon as possible. .

[0004]

In such a pre-plastic type injection device, since the resin that is rotated at a fixed position plasticizes the resin, the in-line screw type injection device that plasticizes with the screw that retracts while rotating. It is said that the plasticization can be performed more uniformly than that of the above, but the plasticization is not always performed uniformly. However, plasticization often becomes non-uniform depending on the state and characteristics of the material. In particular, since the resin does not have a good thermal conductivity, the temperature unevenness is not improved during the flow process and the plasticized state is not uniform, and the resin is measured as it is in the injection cylinder.

Further, conventionally, as shown in FIG. 4, an inflow passage 111 at a portion of the tip end portion of the injection cylinder 110, which is in contact with the plunger forward limit, is bored toward the center portion of the injection cylinder 110. Therefore, the plasticized resin from the resin passage 112 is divided into left and right along the inner peripheral surface 110a by the tip of the plunger located at the forward limit in the initial stage of measurement and thereafter by the resistance of the resin that has flowed in first. Flow in and form a merging portion on the opposite side of the inflow path 111.

[0006] If this merged portion is formed at the bottom of the plunger forward limit, it tends to stay, and it takes time to remove the stagnant resin at the bottom when exchanging the material resin or changing the color. The removal of the stagnant resin requires time because the blanking of a new material is repeatedly performed, and it also causes a loss of material and power consumption.

Further, in the conventional apparatus in which the resin passage communicating between the plasticizing device and the injection device is arranged at an angle of about 90 ° with respect to the axis of the plasticizing cylinder, the resin passage intersects the outflow passage and the inflow passage. A corner is formed inside the portion, and this corner makes it easy for a part of the resin to stay on the downstream side, which may impair the flow of the resin.

The present invention has been conceived in order to solve the above-mentioned conventional problems, and its purpose is to make the temperature of the resin plasticized in the plasticizing cylinder uniform in the resin passage and to generate stagnant resin. It is an object of the present invention to provide a new pre-plastic type injection device capable of preventing the above by obliquely disposing the resin passage and the inflow passage.

[0009]

SUMMARY OF THE INVENTION According to one of the inventions by the above object, a plasticizing cylinder is provided in parallel with an injection cylinder having a plunger inside, and the injection cylinder and the plasticizing cylinder are connected to a plunger advance at the tip of the injection cylinder. The resin passage of the thin tube having the temperature control means on the outer periphery provided over the inflow passage of the part that hits the limit and the outflow passage of the tip of the plasticizing cylinder, and the inflow passage is formed to be inclined toward the inner peripheral surface of the injection cylinder It is that.

In such a structure, flow resistance is apt to be generated by the resin passage formed by the thin tube, the temperature of the resin flowing in the resin passage is leveled by the flow resistance until it flows into the injection cylinder, and the plasticized state is uniform. In addition, the inclined inflow path causes all of the resin to flow in one direction along the inner peripheral surface of the injection cylinder, and there is no merging portion due to shunting. Is also retained.

According to another aspect of the present invention, the tip end of the plasticizing cylinder is set rearward of the tip end of the injection cylinder, and the resin passage extending between the outflow passage and the inflow passage of both the end portions is directed forward. It is provided obliquely at an acute angle, preferably inclined at an angle range of 40 ° to 50 ° with respect to the axis of the plasticizing cylinder.

In such a construction, a large intersection angle is formed between the resin passage and the outflow passage and the inflow passage, and the inclination of the resin passage has an outside angle of 40 ° to 50 ° with respect to the axis of the plasticizing cylinder.
When set to the angle range of, the intersection angle is 130 ° to 14
It is as large as 0 °, so that the resin is less likely to stay at the intersection.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the drawings, 1 is an injection device, 2 is a plasticizing device, and this plasticizing device 2 has a tip portion 22a of a plasticizing cylinder 22 positioned rearward of a tip portion 12a of an injection cylinder 12, They are arranged side by side on the injection device 1. Further, both devices are provided with a resin path 3 obliquely provided over the tip portions 12a and 22a.
Is communicated with.

The injection device 1 has a plunger 10 for injection.
And a hydraulic cylinder 14 for injection in which a piston 13 is connected to the plunger 10 and is connected to the rear end of the injection cylinder 12. ing.

The injection cylinder 12 has an inflow passage 15 for the resin passage 3 at an upper portion of the tip end portion 12a which is in contact with the plunger forward end, and the inflow passage 15 has the same diameter as the resin passage 3 and the inner circumference of the injection cylinder 12. The resin is inclinedly formed toward the surface 12a, and the resin from the resin passage 3 flows in one direction along the inner peripheral surface.

Further, resin drain holes 16 are provided in the upper and lower portions behind the plunger stroke of the injection cylinder 12, and a band heater 17 is provided up to the cylinder periphery behind the resin drain holes 16 to set a long heater zone. is there.

The plasticizing device 2 has a plasticizing screw 20 rotatably mounted therein, and the outflow passage 2 is provided at a tip portion 22a.
1 of the plasticizing cylinder 22, a holding cylinder 23 at the rear end for holding the plasticizing cylinder 22, a hydraulic cylinder 24 for screw forward and backward coupling connected to the rear end of the holding cylinder 23, and the hydraulic cylinder 24. It is composed of a rotation drive device 25 for the screw 20 attached to the rear end.

The drive shaft 25 of the rotary drive device 25 has a rear end portion inserted through a piston 24a of a hydraulic cylinder 24 and connected to a rotary shaft 23a which is axially movably supported in the holding cylinder 23. The rear end of the screw 20 is connected to the front end of the rotary shaft 23a. The rotary shaft 23a is connected to the piston 24a, and the piston 2a
The piston 24a is rotated and moved forward and backward together with 4a.

A band heater 26 is attached to the outer circumference of the plasticizing cylinder 22, and a supply hole 27 is provided upward at the rear end of the plasticizing cylinder 22 fitted with the holding cylinder 23. Further, a mushroom-shaped valve body 28 is attached to the tip of the screw 20, and the inside of the tip of the plasticizing cylinder 22 in which the valve body 28 is located is formed in a conical shape so that the valve body 28 and the valve body 28 are connected to each other. A required flow gap that communicates with the outflow passage 21 is formed, and an annular valve seat 29 is provided in a portion facing the inclined back surface of the valve body 28.

The resin passage 3 is formed by a thin metal tube 30 having an inner diameter of about 5 to 10 mm, and a temperature adjusting means such as a band heater 31 is provided around the outer circumference. The thin tube 30 is connected to the inflow passage 15 having the same diameter of the injection cylinder 12 and the plasticizing cylinder 2.
2, the joints 30a, 30
With b, it is provided at an acute angle to the front.

The inclination angle of the resin path 3 is as shown in FIG.
As shown in FIG. 5, the external angle B is set to 45 ° with respect to the axis AA of the plasticizing cylinder 22, but the inclination angle is 40 °.
The angle may be in the range of 50 ° to 50 °, and in this angle range, the interior angles C and D at the intersection of the resin passage 3 and the outflow passage 15 and the inflow passage 22 are formed to be large at 130 ° to 140 °, respectively. , The angle generated inside the intersecting portion becomes an obtuse angle, and there is no portion on the downstream side where a part of the resin rests.

The injection device 1 and the plasticizing device 2 are integrally connected in two stages, with the holding cylinder 23 mounted and fixed on a support base 18 provided on the hydraulic cylinder 14.
The hydraulic cylinder 14 of the injection device 1 is mounted and fixed on a slidable base block 6 connected to a fixed plate 4 of the mold clamping device via a nozzle touch cylinder 5 and installed on a machine base 7. .

In the above structure, the material resin is supplied to the hole 27.
When it is sent to the plasticizing cylinder 22 from, the material resin is plasticized by the heating by the band heater 26 and the rotation of the screw 20, and is sequentially sent forward by pressure. This resin pressure applies a forward pressure to the screw 20, so that a resin flow gap is secured between the valve body 28 and the valve seat 29 at the tip, and the plasticized resin is sequentially discharged from the outflow passage 21. Road 3
Pumped to. At this time, since the intersection angle between the resin passage 3 and the outflow passage 21 is formed largely due to the inclination of the resin passage 3, the entire amount of the resin flows to the resin passage 3 without staying on the downstream side of the intersection. Go on.

In the resin passage 3, the resin flows into the inflow passage 15 while being further plasticized or mixed with color due to the flow resistance while passing through the thin tube 30. Further, the resin comes to obliquely flow into the injection cylinder 12 through the inclined inflow passage 15, pressurizing the tip end surface of the plunger 10,
The plunger 10 is moved backward and accumulated in the tip portion of the cylinder. This accumulation is performed until the plunger 10 retracts to the set position, and the weighing is completed.

During this measurement, the resin flows in one direction from the inclined inflow passage 15 along the inner peripheral surface 12a of the injection cylinder 12. Further, the flow thereof flows into the cylinder deep portion from the inflow passage 15 so as to swirl as the plunger 10 moves backward due to the resin pressure. Therefore, there is no occurrence of a merging portion on the opposite side of the inflow passage 15.

When the plunger 10 is retracted to the set position, the hydraulic cylinder 24 is retracted to move the screw 20.
Is forcibly moved backward and the valve body 28 is pressed against the valve seat 29. As a result, the inside of the tip of the plasticizing cylinder 22 is closed, and the pressure-feeding of the plasticized resin is temporarily stopped. As a result, a preset amount of resin is accumulated in the front portion of the plunger of the injection cylinder 12. The process up to this point is generally called “measurement”, and then the measured resin is injected.

With the valve body 28 closed, the plunger 1
When 0 is moved forward, the resin in the injection cylinder will move to the nozzle 1
A mold (not shown) is injection-filled from 1. The injection pressure of the plunger 10 also acts on the plasticizing cylinder side via the resin remaining in the resin passage 3. However, since the valve body 28 is in the closed state, the reverse flow of the resin to the plasticizing cylinder side is prevented, and the total amount of the measured resin is the nozzle 11.
Is ejected from.

When the completion of the injection process is confirmed, the hydraulic cylinder 14 moves forward to move the screw 20 forward by a required dimension. As a result, the valve body 28 at the tip is seated on the valve seat 29
A flow path communicating with the flow gap formed on the front surface of the valve body is formed further away. After that, the rotation drive device 25 operates to rotate the screw 20, plasticize the resin, and measure the new plasticized resin.

Although the plasticizing cylinder of the above embodiment has a screw inside, the present invention can also be applied to an inside of a plunger. Therefore, the present invention is particularly limited to a screw pre-plastic injection device. is not.

[0030]

As described above, according to the present invention, the injection cylinder and the plasticizing cylinder are provided on the outer circumference provided over the inflow path of the injection cylinder tip end portion corresponding to the plunger advance limit and the outflow path of the plasticization cylinder tip end. Since they were communicated by the resin path of the thin tube having the temperature control means, the resins were mixed due to the flow resistance while passing through the resin path, which eliminated the temperature unevenness and color unevenness, and the injection-filled resin was It will be homogeneous.

Further, the inflow passage is formed to be inclined toward the inner peripheral surface of the injection cylinder so that the resin from the resin passage flows in one direction along the inner peripheral surface of the injection cylinder. The resin merging portion that occurs at the time of occurrence does not occur, and the resin retention caused by the merging portion is eliminated, so the time required for material resin exchange and color change is shortened compared to before,
It also saves material resin and power consumption.

Further, in terms of structure, it is sufficient that the resin passage is formed by a thin tube and the inflow passage is obliquely provided toward the inner peripheral surface passage of the injection cylinder, so that it is not particularly complicated as compared with the conventional case. Due to the inclination of the resin passage, the angle of the intersection of the resin passage and the inflow passage and the outflow passage is formed to be large, and the retention of the resin at the intersection is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of a pre-plastic injection device according to the present invention.

FIG. 2 is an enlarged view of a main part of the same.

FIG. 3 is a vertical sectional front view of the same.

FIG. 4 is a vertical sectional front view of an injection cylinder showing a conventional inflow path.

FIG. 5 is a schematic view of a main part showing an inclination angle of a resin path.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Injection apparatus 2 Plasticizing apparatus 3 Resin path 10 Injection plunger 12 Injection cylinder 12a Tip part 15 Inflow path 16 Resin drain hole 20 Plasticization screw 21 Outflow path 22 Plasticizing cylinder 22a Outflow path 30 Capillary tube 31 Band heater

Claims (3)

[Claims] 1. A plasticizing cylinder is provided in parallel with an injection cylinder having a plunger inside, and the injection cylinder and the plasticizing cylinder are connected to an inflow passage of a portion of the tip end of the injection cylinder corresponding to the plunger forward limit and an outlet of the plasticizing cylinder tip. In a pre-plastic injection device that communicates with a resin path of a thin tube having a temperature control means on the outer periphery provided over the path, the inflow path is formed to be inclined toward the inner peripheral surface of the injection cylinder. apparatus. 2. A plasticizing cylinder is provided in parallel with an injection cylinder having a plunger inside, and the injection cylinder and the plasticizing cylinder are connected to the injection path at the tip of the injection cylinder and at the end of the plasticizing cylinder. In a pre-plastic type injection device in which a resin passage of a thin tube having a temperature control means on the outer periphery provided over the passage is connected, the tip of the plasticizing cylinder is set rearward of the tip of the injection cylinder, and both tips flow out. A pre-plastic injection device, characterized in that the resin passage extending between the passage and the inflow passage is provided so as to be inclined toward the forward direction at an acute angle. 3. The pre-plasticizer injection device according to claim 2, wherein the resin passage is provided so as to be inclined with respect to the axis of the plasticizing cylinder within an angle range of an external angle of 40 ° to 50 °.