JPS602907Y2 - Nozzle for injection molding machine - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a nozzle for a plastic injection molding machine.

Conventionally, in injection molding machines, before starting injection molding work, a centering operation is performed to align the nozzle, which is the end of the injection device, with the sprue of the mold attached to the fixed plate on the mold clamping device side. must be carried out.

This is because the barrel of the injection device is heated to 200 to 300°C, which causes a large bend in the barrel due to a decrease in the rigidity of the barrel material, unevenness in the material, etc.

This centering operation in a conventional injection device will now be explained with reference to FIGS. 1 and 2 of the accompanying drawings showing the device.

Usually, an injection device includes a heater 1 and a heater 2 provided around the heater 1.
A screw 3 is provided inside the barrel head 2-1 and the barrel head 2-2. gives the torque during plasticization.

Further, the cylinder housing 6 to which the barrel 2-1 is fixed has an injection force generating device consisting of a piston rod 7-1, a piston 7-2, and a piston plate 8, and is located in a space on the side of this rod 7-1. Pressure oil is introduced and its force is transmitted to the bearing case 4 fixed by the nut 9, and the rear end portion 3-1 of the screw is pushed to the left as seen in the figure through the inner thrust bearing, and the hopper is pushed out. 10
After plasticizing the plastic material introduced from the barrel, it is stored at the tip of the barrel and injected into the mold.

At this time, the bearing case 4 slides on the sliding table 11.

Further, the cylinder housing 6 is fixed to the sliding table 11 with bolts 12.

Next, a centering device and method for an injection device having such a configuration will be described. A pivot pin 14 attached to a centering table 13 at the lower part of the sliding table 11 passes through the rear part of the sliding table 11. The sliding table 11 is connected to this pin 14.
Centered on the left and right 1 attached to the front of the tailstock 13.
It has a structure that can be turned on the centering table 13 via a pair of push bolts 15, and after performing left and right centering using this, it is fixed with a lock nut 16.

Furthermore, similar push bolts 1 are installed at four locations on the left, right, front, and back of the centering table 13.
7 and a lock nut 18 in the vertical direction, and insert the tip of the push bolt 17 into the hole 20 drilled in the sliding plate 19 at the bottom of the centering table 13 so as to have an appropriate clearance for the bolt 17. The structure is such that vertical centering is performed using these four push bolts 17 and four lock nuts 18.

Further, the entire injection device has a structure in which a support 22 provided on a part of the bed 21 and a sliding plate 19 are connected by a hydraulic cylinder 23, and the nozzle can be touched by moving back and forth on the bed 21.

Furthermore, in the conventional nozzle, as shown in Fig. 3,
A threaded portion a was provided on the outer surface of the nozzle 24, and this was screwed into a corresponding screw hole provided in the barrel head 2-2 until the contact surface of the nozzle 24 contacted the corresponding contact surface of the barrel head 2-2. .

As mentioned above, conventional injection devices are equipped with 6-output devices on the top, bottom, left and right sides, and the centering work has to be done every time the barrel is replaced, making it extremely troublesome. was.

This invention is for an injection molding machine that speeds up centering work by eliminating the upper and lower six-output devices among the six-output devices on the upper, lower, left, and right sides, and at the same time, simplifies the structure of the lower part of the injection device. The purpose is to obtain a nozzle.

Hereinafter, the present invention will be explained based on the accompanying drawings 4 to 8 showing embodiments thereof.

In the present invention, as shown in FIG. 4, the threaded part of the nozzle 30 is eliminated, and instead, the collar part 301 of the nozzle 30 is connected to the barrel head by a bolt 32 using a stepped retainer ring 31.

2-2, but in this case, nozzle 30
That is, the end surface of the nozzle 30 that contacts the barrel head 2-2 in order to connect the resin passage of the nozzle 30 with the resin passage of the barrel head 2-2 contacts the corresponding contact surface b1 of the barrel head 2-2.・Even when it hits a contact surface,
Note that by determining the dimensions of each part in advance so that a gap C remains between the end face of the flange 30-1 of the nozzle 30 and the end face of the barrel head 2-2, the barrel head 2 -2, and by adjusting the tightening of the bolt 32, the center d of the tip hole 30-2 of the nozzle 30 can be adjusted, if only slightly. It becomes possible.

In addition, the center d of the tip hole 30-2 of the nozzle 30 is eccentric by a distance corresponding to the maximum value E of the amount of large bending due to heating of the barrel (this is referred to as the maximum value of the amount of large bending during hot heating of one barrel). Then, the central axis e of the nozzle 30 and the nozzle 30
The hole is machined by shifting the center axis f of the tip hole 30-2 by a value corresponding to the angle.

The maximum value E of the large amount of hot bending of the barrel described above is determined as follows.

In other words, barrels are usually made of forged alloy steel such as nitrided steel or chromium molybdenum steel, and small ones have an outer diameter of 5oT.
IrI! For larger L1, the outer diameter is usually up to 40mm.
All have almost similar shapes.

And, such a barrel has a straightness of 0.0 when cold.
Although it is manufactured to a thickness of 5 mm or less, when the temperature is raised to the normal molding temperature, that is, 200 to 250°C, a large bend naturally occurs.

According to conventional empirical rules, it is known that this large bend is caused by an eccentricity of about 1 mm at the nozzle tip per meter of barrel length.

Based on this, if the manufacturing process of the barrel is kept constant, for example, for a barrel with a length of 1 m, the amount of eccentricity is 1 m + t, and the length is 4.
In the case of a barrel of m, a large bend of about 4TIrIIt will occur.

In other words, when the length of the barrel is LrIIM, the maximum value E of the large amount of hot bending is (1/1000xL) rrr
m.

Therefore, the final design eccentricity E is the total barrel length Lrran
Then, setting the value to (1/100OXL+1)m is sufficient as the eccentricity correction amount.

Since the present invention has the above-described configuration, when centering the barrel 30, the barrel 2-1 is heated and aligned with respect to the central axis g of the barrel 2-1, as shown in FIG. Te nozzle 30
In a state where the center axis e of the nozzle 30 is eccentric and has a large bend, that is, as shown in FIG. In this case, loosen the bolt 32, rotate the nozzle 30, and bring it horizontally to the position d'. By doing so, it becomes possible to bring the center d of the tip hole 30-2 within the horizontal plane of the barrel center axis g).

Thereafter, the center d' is
is moved to the central axis g1 of the barrel 2-2, that is, to the position of the center of the spool of the mold.

However, the six-output device shown in FIGS. 7 and 8 lacks the upper and lower six-output devices shown in FIGS. 1 and 2, that is, the lower centering table 13 and attached push bolts 17, lock nuts 18, etc. .

1. Since the present invention has the above-mentioned configuration, vertical centering can be performed by rotating the nozzle relative to the barrel head during nozzle centering work, which was previously required. Of the 6 output devices on the left and right,
The upper and lower six-output devices are not required, and therefore, the centering work can be speeded up, thereby improving productivity.

Furthermore, the conventional three-layer structure shown in Figures 1 and 2 is now
The present invention has a two-layer structure, which simplifies the structure and promotes weight reduction, which has a very large effect.

[Brief explanation of drawings]

Fig. 1 is a partially cutaway schematic diagram of a conventional injection device, Fig. 2 is a view from the ■-■ arrow in Fig. 1, Fig. 3 is a detailed sectional view of a conventional nozzle section, and Fig. 4 is a diagram of the present invention. A detailed sectional view of one embodiment of the nozzle, FIG. 5 is an explanatory view showing the state of the barrel during heating, FIG. 6 is an explanatory view of the centering operation, and FIG. The partially cutaway schematic diagram, FIG. 8, is a view taken along the ■-■ arrow in FIG. 7. 2-1: Barrel, 2-2: Barrel head, 30: Nozzle, 31: Retainer ring, 32: Bolt , 30-2...
...Tip hole, b...Abutment surface, d...
... Center of nozzle hole, f ... Center axis of nozzle tip hole, G ... Center axis of palace, E ... Maximum value of barrel bending.

Claims (1)

[Scope of utility model registration request] In a nozzle for a plastic injection molding machine, nozzle 30
The center position d of the tip hole 30-2 is eccentric from the barrel center g by the maximum amount of large hot bending amount of the barrel, and the stepped retainer is bolted to the barrel head 2-2. The collar portion 30-1 pressed by the ring 31 is shaped, and the abutment surface, which is the rear end surface of the part of the nozzle 30 fitted into the barrel head 2-2, is attached to the corresponding contact surface of the barrel head 2-2. In the state of contact, the end surface of the flange portion 30-1 and the barrel head 2-
The nozzle is formed so that a predetermined gap C remains between the end face of the barrel head 2-2, and the retainer ring is tightened at the front of the nozzle, which is rotatably attached to the barrel head 2-2.