JPS5845341B2 - extrusion head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an extrusion head for extrusion molding materials such as rubber and plastic for the purpose of molding multiple pieces.

Conventionally, in a head for extrusion molding of materials such as rubber and plastic for the purpose of producing multiple pieces, a method for controlling the flow rate of the material is as shown in Fig. 5, by installing a head at a branch point where the material exiting the extrusion screw S branches. Or, as shown in FIG. 6, a conical flow path K is formed near the end of the flow path after branching, and a conical flow path K is formed concentrically within the flow path. There was a device that provided a conical plug B corresponding to the die T side and moved the plug B forward and backward to adjust the cross-sectional area of the flow path. When the flow rate increases (decreases), the flow rate in the branch flow path on the other side decreases (increases), making independent adjustment impossible.
In this type, the length of the flow path from the branch point to the die is long, so it is difficult to control the flow rate because differences in resistance are likely to occur due to the flow path shape, surface roughness of the flow path wall, temperature differences, etc. However, in order to make the cross-sectional shape of the product molded by each die the same, the take-off speed must be changed for each die, and therefore multiple take-off devices must be installed accordingly. Although the above-mentioned drawbacks have been solved to some extent, there is a drawback that the stopper B cannot be adjusted during extrusion work because it must be operated from the die side.

In view of the above, the present invention provides an extrusion head in which the flow rate can be adjusted independently for each branch flow path, and the flow rate can be adjusted even during operation.

The gist of the invention is that a cylinder is provided near the end of the flow path after branching, the cylinder is fixed to the head body via an arm, a piston having a tapered part is fitted into the cylinder, and the cylinder is fixed to the head body through an arm. The part corresponds to the tapered hole part formed at the end of the branch flow path, and the piston is configured to move forward and backward from the outside through a hole passing through the arm part from the side outside of the head main body.

Below, illustrations of this invention will be explained.

In FIGS. 1 to 3, 1 is an extrusion screw;
1a is a screw cylinder.

Head body 2 fixed to the tip of the screw cylinder 1a
has two branch channels 17, 17, and a stepped portion with an enlarged diameter is formed at the end of the channel 17, and a torpedo block 23 is inserted into the stepped portion by a bolt 13 via an adapter 10. Fixed.

The torpedo block is integrated by fastening the torpedo front 4 and torpedo IJ 73 with bolts 5. A cylinder 4b is concentric with the flange portion 4a and has an outer diameter that forms a predetermined flow path 18 between the inner diameter surface thereof, and the cylinder 4b and the flange portion 4a are arranged in a direction perpendicular to the arrangement direction of the branch flow paths 1γ. The arm portion 4c is integrally formed with the arm portion 4c.
is formed so that its axis passes through the center of the cylinder 4b.

The torpedo rear 3 also includes a flange portion 3a, a cylinder 3b1, and an arm portion 3C so as to correspond to the torpedo front 4, and the bottom of the cylinder 3b is formed into a conical portion.

Then, as shown in FIG. 3, the flange portion 3a+4a+
Square holes 23a, 23b are provided on both left and right sides of the cylinder 3b, so as to pass through the arms 3c, 4c and the cylinders 3b, 4b.
Both square holes are bored perpendicularly to the axial center of the cylinder 3b with a predetermined step in the axial direction of the cylinder 3b.

The square holes 23a and 23b are formed by carving opposing rectangular grooves in the mating surfaces of the torpedo front 4 and torpedo rear 3.

Reference numeral 8 denotes a rod cam whose ends are slidably fitted into square holes 23a and 23b, respectively, and are bent and molded to have an inclined part in the middle, and the length of the inclined part is a predetermined value from the inner diameter of the cylinders 3b and 4b. The rod cam 8 is formed to have a short length so that the rod cam 8 can slide from side to side.

7 is a piston whose base part is slidably fitted into the inner diameter of the cylinder 4b, whose tip part is formed into a tapered shape and projects from the open end of the cylinder 4b, and whose base part corresponds to the inclined part of the rod cam 8. A backup plate 6 having grooves carved therein and grooves corresponding to the grooves is fixed by bolts 9, and the piston 7 is moved back and forth in the axial direction by the left and right movement of the rod cam 8.

Adjustment bolts 14, 14 have square holes 23a, 2, respectively.
Head main body 2 so as to come into contact with both ends of rod cam 8 in 3b.
are screwed together.

Tapered holes corresponding to the tapered tip of the cylinder 4b and the tapered tip of the piston 7 are bored in the adapter 10, and a conical flow path 19 is formed between the cylinder 4b and the piston 7.

12 is a die in which a molding hole 25 corresponding to the product shape is bored, and a bolt 1 is inserted into the adapter 10 so as to face the piston 7.
It is fixed by 3.

Next, this invention will be explained in detail.

When a molten material such as rubber or plastic is pumped by the extrusion screw 1, the branch flow path 1γ is short, so the difference in resistance and temperature due to the shape of the flow path and the surface roughness of the wall are extremely small, so the material is almost Since the material is extruded from the forming hole 25 after passing through the branch flow path 17 and passing through the flow paths 18 and 19 under the same pressure, the flow rate of the material to the two forming holes is equal, so even if the product is taken up by the same taking-off device. The cross-sectional shapes of the products will be the same.

If for some reason the cross-sectional shape of the product extruded from the die on one side is smaller than the predetermined value, adjust the adjustment screw 14 on that side to move the piston 7 forward (backward) via the rod cam 8. ) to narrow (expand) the cross-sectional area of the flow path 19.

In this case, since there is no change in the channel 19 corresponding to the die 12 on the other side, the adjustment on one side has almost no effect.

According to this invention, even if the flow path to each die is branched as described above, the length of the flow path after branching is short, so it is close to a single flow path, so the shape of the flow path and the surface roughness of the flow path wall are There is almost no difference in resistance or temperature caused by extrusion, and the flow rate adjustment is performed independently for each die, so it does not affect the other die, and the flow rate can be adjusted during extrusion work. This has advantages such as easy control and the ability to operate with a single product take-up device.

Note that FIG. 4 shows the case of manufacturing a tube, in which a cylindrical part is formed at the tip of the taper part of the piston, and a hole having a predetermined gap with the outer diameter of the cylinder is formed on the die side. configured to drill.

Furthermore, the present invention is not limited to the above description and illustrated examples, and the embodiments thereof can be changed without departing from the technical idea of the present invention.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, FIG. 1 is a front view, FIG. 2 is a sectional plan view taken along the line P-P in FIG. 1, and FIG. 3 is a side sectional view. FIG. 4 is a side sectional view showing another embodiment, and FIGS. 5 and 6 are plan sectional views showing a conventional flow rate control method. 2...Head body, 3a, 4a...Flange portion, 3b, 4b...Cylinder, 3C
94C... Arm, 7... Piston, 8
...Stand cam, 10...Adapter, 12
...Die, 19...Flow path. 17... Branch flow path, 18°

Claims (1)

[Claims] 1. In an extrusion head that is equipped with a plurality of branch channels and extrudes a material such as rubber or plastic for the purpose of producing a large number of pieces, there is a wall surface in the channel near the end of each branch channel. A bottomed cylinder having a predetermined gap therebetween is disposed concentrically and opened toward the die, and the cylinder has a bottomed cylinder formed on the outer periphery of the cylinder substantially perpendicular to the arrangement direction of the branch flow paths. The piston is fixed to the head main body via an arm portion protruding in the direction, a piston is slidably fitted into the cylinder, and a tapered portion is formed at a portion of the piston that protrudes from the cylinder. The tapered portion concentrically corresponds to a tapered hole formed at the end of the branch flow path, and the piston adjusts the longitudinal position of the piston through a hole passing through the head main body, the arm portion, and the cylinder. An extrusion head characterized in that it comprises means.