JP7741839B2 - Extrusion Head - Google Patents

Description

The present invention relates to an extrusion head for extruding a plastic rubber material into a tubular body.

A variety of extrusion heads, or so-called crossheads, have been known for extruding plastic rubber materials into tubular bodies. For example, Patent Document 1 below proposes an extruder that can improve runout accuracy by incorporating an alignment mechanism that positions the center of the die and the center of the crosshead.

Japanese Patent Application Laid-Open No. 2008-290367

However, the extrusion head in Patent Document 1 has a complex structure, which poses problems in that maintenance requires a significant amount of time, and adjustment work after maintenance also requires a significant amount of time.

The present invention was devised in light of the above-mentioned circumstances, and its primary objective is to provide an extrusion head that is easy to maintain and reduces the adjustment time after maintenance.

The present invention relates to an extrusion head for extruding a plastic rubber material into a tubular body, comprising: a die having an opening for forming the outer peripheral shape of the tubular body; a spindle having a tapered portion for forming the inner peripheral shape of the tubular body and a first threaded portion provided on the axially opposite side of the tapered portion; a support portion that supports the spindle so that it can move only in the axial direction; and an adjustment mechanism for adjusting the distance between the opening and the tapered portion, wherein the adjustment mechanism includes a first gear having a second threaded portion threadedly connected to the first threaded portion, a second gear that meshes with the first gear, and a drive portion for rotating the second gear, wherein the second gear is configured to be movable between a first position where it meshes with the first gear and a second position spaced apart from the first gear.

By having the above-mentioned configuration, the extrusion head of the present invention is easy to maintain and can also reduce adjustment time after maintenance.

1 is a cross-sectional view showing an embodiment of an extrusion head of the present invention. FIG. 10 is a schematic cross-sectional view of the extrusion head in a state where the second gear has moved to a second position. FIG. 4 is a schematic cross-sectional view of the adjustment mechanism as seen from the upstream side. FIG. 10 is a schematic cross-sectional view of an adjustment mechanism according to a second embodiment. FIG. 10 is a schematic cross-sectional view of an adjustment mechanism according to a third embodiment.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
Fig. 1 is a schematic cross-sectional view showing an extrusion head 1 of this embodiment. As shown in Fig. 1, the extrusion head 1 of this embodiment is used to extrude a rubber material G having plasticity as a tubular body G1.

The extrusion head 1 of this embodiment includes a die 2 for forming the outer peripheral shape of the tubular body G1 and a spindle 3 for forming the inner peripheral shape of the tubular body G1. The die 2 of this embodiment has an opening 2a for forming the outer peripheral shape of the tubular body G1. The spindle 3 of this embodiment has a tapered portion 3a for forming the inner peripheral shape of the tubular body G1 and a first threaded portion 3b provided on the axially opposite side of the tapered portion 3a.

The extrusion head 1 includes, for example, an attachment 4 arranged radially outward from the spindle 3. The attachment 4 preferably has a support portion 4a that supports the spindle 3 so that it can move only in the axial direction. Such a support portion 4a can prevent the spindle 3 from rotating around its axis, and allows the spindle 3 to move axially even when a rotational force acts on the first screw portion 3b.

The extrusion head 1 of this embodiment includes an adjustment mechanism 5 for adjusting the distance L between the opening 2a and the tapered portion 3a. Such an adjustment mechanism 5 can easily adjust the thickness t of the tubular body G1.

The adjustment mechanism 5 of this embodiment includes a first gear 6 having a second threaded portion 6a threadedly connected to the first threaded portion 3b, a second gear 7 that meshes with the first gear 6, and a drive unit 8 for rotating the second gear 7. By rotating the drive unit 8, this adjustment mechanism 5 can rotate the first gear 6 via the second gear 7, and the spindle 3 can be moved axially via the threaded connection between the second threaded portion 6a and the first threaded portion 3b, making it possible to easily adjust the thickness t of the tubular body G1.

Figure 2 is a schematic cross-sectional view of the extrusion head 1 with the second gear 7 moved to the second position P2. As shown in Figures 1 and 2, the second gear 7 of this embodiment is configured to be movable between a first position P1 where it meshes with the first gear 6, and a second position P2 where it is spaced apart from the first gear 6. This second gear 7 can be spaced apart from the first gear 6 when the first gear 6 or spindle 3 is disassembled, making maintenance easier.

Furthermore, with this type of adjustment mechanism 5, extrusion operations can be resumed after maintenance simply by moving the second gear 7 to the first position P1 and adjusting the axial position of the spindle 3, thereby shortening the adjustment time after maintenance. Therefore, the extrusion head 1 of this embodiment is easy to maintain and can also shorten the adjustment time after maintenance.

In a more preferred embodiment, the extrusion head 1 includes a base 9 that supports the attachment 4. The base 9 is preferably provided with an inlet 9a for introducing the rubber material G. At the boundary between the base 9 and the attachment 4, for example, a flow path (not shown) for flowing the rubber material G is provided. Note that if a separate flow path for the rubber material G can be secured, the base 9 may be integral with the attachment 4, for example.

The spindle 3 in this embodiment has a hollow portion 3c that penetrates the spindle 3. For example, the core C of the tubular body G1 can be passed through the hollow portion 3c so that it can move from the upstream side U to the downstream side D in the axial direction.

In the extrusion head 1 of this embodiment, a core C is inserted into the hollow portion 3c from the upstream side U of the spindle 3, and rubber material G is coated around the core C as a tubular body G1 at the die 2 on the downstream side D. This type of extrusion head 1 can smoothly coat the rubber material G around the core C. Note that the core C may be, for example, a wire. The tubular body G1 may also be, for example, a hollow tubular body G1 without a core C.

The adjustment mechanism 5 preferably has an alignment means 10 for adjusting the axial position of the tapered portion 3a of the spindle 3 relative to the axial position of the opening 2a of the die 2. Such an adjustment mechanism 5 can adjust the overall thickness t of the tubular body G1 using the first gear 6, second gear 7, and drive unit 8, and can adjust variations in the circumferential thickness t of the tubular body G1 using the alignment means 10.

The alignment means 10 in this embodiment includes a drive motor 10a provided on the die 2 and an elastic member 10b provided in a position facing the drive motor 10a across the opening 2a. The alignment means 10 includes, for example, two drive motors 10a and two elastic members 10b. It is desirable that the two drive motors 10a be arranged in directions perpendicular to each other.

Such an alignment means 10 can automatically adjust the thickness t of the tubular body G1 to always be constant by detecting the thickness t of the tubular body G1 using a sensor (not shown) and driving the drive motor 10a. Note that the alignment means 10 may also be manually adjusted using, for example, multiple alignment bolts arranged around the periphery of the die 2.

The drive motor 10a may be, for example, a stepping motor, servo motor, geared motor, or the like. The elastic member 10b may preferably be, for example, a plurality of disc springs. The alignment means 10 may, for example, be provided with a position sensor (not shown) on the elastic member 10b side, to feedback control the drive motor 10a. Such alignment means 10 can improve runout accuracy through automatic alignment.

The first gear 6 and second gear 7 of the adjustment mechanism 5 are preferably bevel gears. In this embodiment, the first gear 6 and second gear 7 are arranged so that their axial directions are perpendicular to each other. With this type of adjustment mechanism 5, the movement of the second gear 7 allows for ample space to be secured for disassembling the first gear 6 and spindle 3, further improving maintainability.

It is desirable that the first gear 6 and the second gear 7 have the same number of teeth. Such an adjustment mechanism 5 makes it easy to adjust the axial position of the spindle 3, making adjustment work after maintenance more efficient and reducing the adjustment time after maintenance. However, the first gear 6 and the second gear 7 are not limited to this form and may be, for example, spur gears or helical gears.

In this embodiment, the second gear 7 is configured to be rotatable between a first position P1 and a second position P2. This type of adjustment mechanism 5 makes it easy to move the second gear 7, helping to improve maintainability.

The adjustment mechanism 5 preferably includes positioning means 11 that determines the first position P1 of the second gear 7. Such an adjustment mechanism 5 makes it easy to adjust the meshing between the first gear 6 and the second gear 7, shortening the adjustment time after maintenance.

The extrusion head 1 includes, for example, a first member 12 that indirectly supports the first gear 6 and a second member 13 that indirectly supports the second gear 7. The first member 12 supports the first gear 6 via, for example, the base 9, the attachment 4, and the spindle 3. The second member 13 supports the second gear 7 via, for example, the drive unit 8. Such first member 12 and second member 13 are useful for moving the second gear 7 with a simple configuration.

The positioning means 11 includes a tapered hole 12a formed in one of the first member 12 and the second member 13 (in this embodiment, the first member 12), and a tapered protrusion 13a formed in the other of the first member 12 and the second member 13 (in this embodiment, the second member 13). It is desirable that the tapered protrusion 13a be shaped so that its entirety can come into contact with the tapered hole 12a. Such a positioning means 11 can reliably determine the first position P1 of the second gear 7 as it rotates.

Figure 3 is a schematic cross-sectional view of the adjustment mechanism 5 as viewed from the upstream side U. As shown in Figure 3, the adjustment mechanism 5 of this embodiment includes a locking means 14 that fixes the second gear 7 at the first position P1. The locking means 14 includes, for example, a plurality of locking bolts 14a that fix the first member 12 and the second member 13 together. Such an adjustment mechanism 5 can reliably fix the second gear 7 at the first position P1 with a simple configuration.

One end of the lock bolt 14a is fixed to the first member 12 or the second member 13 (in this embodiment, the second member 13) so that it can swing freely. The adjustment mechanism 5 can move the second gear 7 while the lock bolt 14a is separated from the first member 12, as shown by the two-dot chain line, for example. Such a locking means 14 is easy to lock and unlock, helps improve maintainability, and is also cost-effective.

Figure 4 is a schematic cross-sectional view of the adjustment mechanism 20 of the second embodiment. Elements that are the same as those in the above-described embodiment are given the same reference numerals, and their description will be omitted. As shown in Figure 4, the adjustment mechanism 20 of the second embodiment, like the above-described adjustment mechanism 5, includes a first gear 6 threadedly connected to the spindle 3 (shown in Figure 1), a second gear 7 that meshes with the first gear 6, and a drive unit 8 for rotating the second gear 7.

As in the above-described embodiment, the first gear 6 is preferably indirectly supported by the first member 21. As in the above-described embodiment, the second gear 7 in the second embodiment is indirectly supported by the second member 22. Such a first member 21 and second member 22 are useful for moving the second gear 7 with a simple configuration.

The second gear 7 of the adjustment mechanism 20 of the second embodiment is configured to be able to move linearly between a first position P1 where it meshes with the first gear 6 and a second position P2 (not shown) where it is spaced apart from the first gear 6. The adjustment mechanism 20 includes, for example, a guide means 23 for linearly moving the second gear 7.

The guide means 23 is preferably a linear guide. The guide means 23 includes, for example, a rail portion 23a attached to the first member 21 and a guide portion 23b attached to the second member 22. Such an adjustment mechanism 20 can move the second gear 7 linearly with high precision.

The adjustment mechanism 20 of the second embodiment, like the adjustment mechanism 5 described above, includes a positioning means 24 that determines the first position P1 of the second gear 7. The positioning means 24 includes, for example, a positioning hole 24a formed in the first member 21 and a positioning pin 24b that can be inserted into the positioning hole 24a.

The positioning means 24 includes at least two positioning pins 24b, two in the second embodiment. Such positioning means 24 can reliably determine the first position P1 of the second gear 7, which moves linearly.

The adjustment mechanism 20 of the second embodiment, like the adjustment mechanism 5 described above, includes a locking means 14 (shown in Figure 3) that fixes the second gear 7 at the first position P1. This type of adjustment mechanism 20 has a simple configuration and can reliably fix the second gear 7 at the first position P1.

Figure 5 is a schematic cross-sectional view of the adjustment mechanism 30 of the third embodiment. Elements that are the same as those in the above-described embodiments are given the same reference numerals, and their description will be omitted. As shown in Figure 5, the adjustment mechanism 30 of the third embodiment, like the above-described adjustment mechanism 5, includes a first gear 6 threadedly connected to the spindle 3 (shown in Figure 1), a second gear 7 that meshes with the first gear 6, and a drive unit 8 for rotating the second gear 7.

As in the above-described embodiment, the first gear 6 is preferably indirectly supported by the first member 31. As in the above-described embodiment, the second gear 7 in the third embodiment is indirectly supported by the second member 32. Such a first member 31 and second member 32 are useful for moving the second gear 7 with a simple configuration.

The second gear 7 of the adjustment mechanism 30 of the third embodiment, like the adjustment mechanism 20 described above, is configured to be linearly movable between a first position P1 where it meshes with the first gear 6 and a second position P2 (not shown) where it is spaced apart from the first gear 6. Like the adjustment mechanism 20 described above, the adjustment mechanism 30 of the third embodiment includes guide means 23 for linearly moving the second gear 7.

The adjustment mechanism 30 of the third embodiment, like the adjustment mechanism 5 described above, includes a positioning means 33 that determines the first position P1 of the second gear 7. The positioning means 33 includes, for example, a fixed shaft 33a formed on the first member 21 and a ball bushing 33b that contacts the fixed shaft 33a.

The positioning means 33 includes at least two fixed shafts 33a, two in the third embodiment. Such positioning means 33 can reliably determine the first position P1 of the second gear 7, which moves linearly.

The adjustment mechanism 30 of the third embodiment, like the adjustment mechanism 5 described above, includes a locking means 14 (shown in Figure 1) that fixes the second gear 7 at the first position P1. This type of adjustment mechanism 30 has a simple configuration and can reliably fix the second gear 7 at the first position P1.

The above describes in detail a particularly preferred embodiment of the present invention, but the present invention is not limited to the above embodiment and can be modified and implemented in various ways.

[Note]
The present invention is as follows.

[Invention 1]
1. An extrusion head for extruding a plastic rubber material into a tubular body, comprising:
a die having an opening for forming the outer peripheral shape of the tubular body;
a spindle having a tapered portion for forming an inner peripheral shape of the tubular body and a first screw portion provided on the axially opposite side of the tapered portion;
a support portion that supports the spindle so that the spindle is movable only in the axial direction;
an adjustment mechanism for adjusting the distance between the opening and the tapered portion;
the adjustment mechanism includes a first gear having a second screw portion threadedly coupled to the first screw portion, a second gear meshing with the first gear, and a drive portion for rotating the second gear,
The second gear is configured to be movable between a first position in which it meshes with the first gear and a second position in which it is spaced apart from the first gear.
Extrusion head.

[Invention 2]
2. The extrusion head according to claim 1, wherein the first gear and the second gear are each bevel gears.

[Invention 3]
The extrusion head according to claim 1, wherein the second gear is configured to be pivotable between the first position and the second position.

[Invention 4]
2. The extrusion head according to claim 1, wherein the second gear is configured to be linearly movable between the first position and the second position.

[Invention 5]
2. An extrusion head according to claim 1, wherein the adjustment mechanism includes positioning means for defining the first position of the second gear.

[Invention 6]
a first member indirectly supporting the first gear and a second member indirectly supporting the second gear,
An extrusion head as described in present invention 5, wherein the positioning means includes a tapered hole portion formed in one of the first member and the second member, and a tapered protrusion portion formed in the other of the first member and the second member and capable of contacting the tapered hole portion.

[Invention 7]
6. An extrusion head according to claim 5, wherein the positioning means includes at least two positioning pins.

[Invention 8]
8. The extrusion head according to any one of claims 1 to 7, wherein the spindle has a hollow portion passing through the spindle.

[Invention 9]
8. The extrusion head according to any one of claims 1 to 7, wherein the adjustment mechanism has alignment means for adjusting the axial position of the tapered portion relative to the axial position of the opening.

[Invention 10]
An extrusion head according to claim 9, wherein the aligning means includes a drive motor provided in the die and an elastic member provided at a position facing the drive motor across the opening.

REFERENCE SIGNS LIST 1 Extrusion head 2 Die 2a Opening 3 Spindle 3a Tapered portion 3b First screw portion 4a Support portion 5 Adjustment mechanism 6 First gear 6a Second screw portion 7 Second gear 8 Drive portion

Claims (10)

1. An extrusion head for extruding a plastic rubber material into a tubular body, comprising:
a die having an opening for forming the outer peripheral shape of the tubular body;
a spindle having a tapered portion for forming an inner peripheral shape of the tubular body and a first screw portion provided on the axially opposite side of the tapered portion;
a support portion that supports the spindle so that the spindle is movable only in the axial direction;
an adjustment mechanism for adjusting the distance between the opening and the tapered portion;
the adjustment mechanism includes a first gear having a second screw portion threadedly coupled to the first screw portion, a second gear meshing with the first gear, and a drive portion for rotating the second gear,
The second gear is configured to be movable between a first position in which it meshes with the first gear and a second position in which it is spaced apart from the first gear.
Extrusion head. The extrusion head of claim 1, wherein the first gear and the second gear are each bevel gears. The extrusion head of claim 1, wherein the second gear is configured to be pivotable between the first position and the second position. The extrusion head of claim 1, wherein the second gear is configured to be linearly movable between the first position and the second position. The extrusion head of claim 1, wherein the adjustment mechanism includes positioning means for defining the first position of the second gear. a first member indirectly supporting the first gear and a second member indirectly supporting the second gear,
6. The extrusion head according to claim 5, wherein the positioning means includes a tapered hole portion formed in one of the first member and the second member, and a tapered protrusion portion formed in the other of the first member and the second member and capable of contacting the tapered hole portion. The extrusion head of claim 5, wherein the positioning means includes at least two positioning pins. An extrusion head according to any one of claims 1 to 7, wherein the spindle has a hollow portion extending therethrough. An extrusion head according to any one of claims 1 to 7, wherein the adjustment mechanism has a centering means for adjusting the axial position of the tapered portion relative to the axial position of the opening. The extrusion head described in claim 9, wherein the alignment means includes a drive motor provided in the die and an elastic member provided in a position facing the drive motor across the opening.