JP7167613B2 - Die plate and rubber extrusion device - Google Patents

Description

The present invention relates to a die plate for a rubber extruder and a rubber extrusion apparatus including the die plate.

Conventionally, die plates used in rubber extruders are known. The die plate is provided on the downstream side of the rubber extruder in the rubber extruding direction in order to define the finished cross-sectional shape of the rubber member extruded from the rubber extruder. For example, Patent Literature 1 below proposes a die plate in which rubber retaining portions are provided on both sides of a rubber extrusion channel to prevent the edge portion of an extruded rubber member from being cut.

JP 2014-205331 A

However, the die plate of Patent Document 1 has a problem that the surface of the extruded rubber member undulates when rubber is extruded at high speed. Therefore, in the rubber extrusion apparatus including the die plate of Patent Document 1, it is difficult to increase the extrusion speed, and there is a problem that the productivity of rubber extrusion molding is lowered.

SUMMARY OF THE INVENTION The present invention has been devised in view of the actual situation as described above, and its main object is to provide a die plate and a rubber extrusion apparatus including the die plate that can improve the productivity of rubber extrusion molding.

The present invention is a die plate for a rubber extruder, comprising a plate body having a first surface facing the rubber extruder and a second surface opposite thereto, the plate body comprising the first an inlet opening on the surface side for receiving the rubber from the rubber extruder; an outlet opening on the second surface side for discharging the rubber in a finished cross-sectional shape; A rubber channel that is a space communicating between an inlet and the discharge port is provided, and in a front view of the first surface, the inlet is long in the direction of the first axis and perpendicular to the direction of the first axis. The rubber channel has a length in the direction of the second axis from the inlet toward the outlet in a cross section perpendicular to the direction of the first axis. It is characterized by including a narrowed passage portion that decreases, wherein the narrowed passage portion is formed over the entire range in the direction of the first axis.

In the die plate of the present invention, it is preferable that the rubber channel includes a channel-identical portion having a constant length in the second axial direction in a cross section orthogonal to the first axial direction.

In the die plate of the present invention, the same flow path portion has a length in a third axial direction orthogonal to the second axial direction in a cross section orthogonal to the first axial direction, which is the same as the first surface and the second surface. is preferably 25% or more of the distance from

In the die plate of the present invention, a rear side chamfer is provided between the narrowed passage portion and the same passage portion, and the rear chamfer extends over the entire range in the first axial direction. preferably formed.

In the die plate of the present invention, it is desirable that the back chamfer is chamfered in an arc shape.

In the die plate of the present invention, it is preferable that a front surface chamfer is provided between the same flow path portion and the second surface.

The present invention provides a rubber extruder including the die plate described above, the rubber extruder having an extrusion port for extruding the rubber, and a preformer connecting the die plate and the rubber extruder, The preformer has an extrusion channel that is a space communicating between the inlet and the extrusion port, and the length of the extrusion channel on the die plate side in the second axial direction is equal to the length of the inlet It is characterized by being approximately equal to the length in the second axial direction.

In the rubber extruder of the present invention, the rubber extruder includes a first rubber extruder for extruding a first rubber and a second rubber extruder for extruding a second rubber, and and the second rubber.

In the die plate of the present invention, the rubber flow channel includes a flow channel narrowing portion whose length in the second axial direction decreases from the inlet toward the outlet in a cross section orthogonal to the first axial direction, and the flow The narrowed portion is formed over the entire range in the direction of the first axis. Such a die plate allows the rubber to flow smoothly within the rubber channel, and can smooth the surface of the extruded rubber member even when the rubber is extruded at high speed. Therefore, the die plate of the present invention can improve the productivity of rubber extrusion molding.

It is a sectional view showing one embodiment of a rubber extrusion device of the present invention. It is a front view of the 1st surface of the die plate of this embodiment. It is an enlarged sectional view of a die plate. FIG. 4 is an enlarged cross-sectional view of a die plate of another embodiment;

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view of a rubber extrusion device 1 of this embodiment. As shown in FIG. 1 , the rubber extruder 1 of this embodiment includes a rubber extruder 2 , a die plate 3 , and a preformer 4 connecting the die plate 3 and the rubber extruder 2 . The rubber extrusion device 1 is suitable for, for example, extruding a rubber member Gm suitably used for tire parts such as tread rubber.

The rubber extruder 2, for example, uses a screw 5 to knead the rubber G and extrude it in the extrusion direction d. As the rubber extruder 2, a conventionally known one suitable for extruding the rubber G can be appropriately adopted. The rubber extruder 2 has an extrusion port 2a for extruding the rubber G, for example. In the rubber extruder 1 of this embodiment, an extrusion port 2 a of a rubber extruder 2 is connected to a preformer 4 .

The rubber extruders 2 include, for example, a first rubber extruder 2A for extruding a first rubber G1 and a second rubber extruder 2B for extruding a second rubber G2. 2 A of 1st rubber extruders and the 2nd rubber extruder 2B of this embodiment are each provided with the extrusion mouth 2a and the screw 5. As shown in FIG. The number of rubber extruders 2 is not limited to two, and may be one or three or more.

When there are two rubber extruders 2, the first rubber G1 and the second rubber G2 may have different viscosities, for example. When the rubber member Gm is the tread rubber of a tire, the rubber member Gm includes, for example, a high-viscosity first rubber G1 and a low-viscosity second rubber G2, thereby achieving both steering stability and fuel efficiency. It is possible to manufacture tires that can

The die plate 3 of this embodiment is suitably used to define the rubber G extruded from the rubber extruder 2 as the finished cross-sectional shape of the rubber member Gm. The die plate 3 includes, for example, a plate body 6 having a first surface 6a facing the rubber extruder 2 and a second surface 6b opposite thereto.

The plate body 6 has an inlet 6c for receiving the rubber G from the rubber extruder 2, an outlet 6d for discharging the rubber G in a finished cross-sectional shape, and a space connecting the inlet 6c and the outlet 6d. It is desirable to have a rubber channel 7 which is The inlet 6c of this embodiment is open on the first surface 6a side. The ejection port 6d of this embodiment is open on the second surface 6b side.

FIG. 2 is a front view of the first surface 6a of the die plate 3. FIG. As shown in FIG. 2, in a front view of the first surface 6a of the die plate 3, the inlet 6c is long in the first axial direction a and extends in the second axial direction b orthogonal to the first axial direction a. A short elongated opening is desirable. Such an inflow port 6 c can efficiently feed a large amount of rubber G into the rubber flow path 7 .

FIG. 3 is an enlarged sectional view of the die plate 3. FIG. As shown in FIGS. 2 and 3, the rubber flow path 7 of this embodiment has a length in the second axial direction b from the inlet 6c toward the outlet 6d in a cross section perpendicular to the first axial direction a. It includes a flow passage narrowing portion 7a in which the height L1 is reduced. It is desirable that the narrowed passage portion 7a be formed over the entire range in the first axial direction a.

Such a die plate 3 can smoothly flow the rubber G in the rubber flow path 7, and can smooth the surface of the extruded rubber member Gm even when the rubber G is extruded at high speed. In addition, even when there are two rubber extruders 2 and the difference in viscosity between the first rubber G1 and the second rubber G2 is large, the die plate 3 keeps the surface of the rubber member Gm to be extruded. can be smoothed. Therefore, the die plate 3 of this embodiment can improve the productivity of rubber extrusion molding.

As a more preferable embodiment, the rubber flow path 7 is formed in the same flow path portion where the length L2 in the second axial direction b is constant on the discharge port 6d side of the flow path contraction portion 7a in the cross section orthogonal to the first axial direction a. 7b included. It is desirable that the same flow path portion 7b has substantially the same finished cross-sectional shape as the rubber member Gm. Such a rubber flow path 7 can define an arbitrary finished cross-sectional shape of the rubber member Gm.

In the cross section orthogonal to the first axial direction a, the channel-identical portion 7b preferably has a length L3 in the third axial direction c orthogonal to the second axial direction b that is the distance between the first surface 6a and the second surface 6b. It is 25% or more of the distance L4. Such a channel-identical portion 7b can improve the accuracy of the finished cross-sectional shape of the rubber member Gm. In addition, the extrusion direction d of the rubber G in the present embodiment is generally along the third axial direction c.

As shown in FIGS. 1 to 3, the plate body 6 of this embodiment includes a first plate 6A provided on one side in the second axial direction b and a second plate 6B provided on the opposite side. contains. The first plate 6A has, for example, recesses forming rubber flow paths 7 . The second plate 6B has, for example, a substantially rectangular parallelepiped shape, and constitutes a part of the rubber channel 7. As shown in FIG. Such a plate body 6 is easy to maintain, and when changing the shape of the rubber flow path 7, only the first plate 6A needs to be replaced, so production costs can be reduced.

As shown in FIG. 1, the preformer 4 has, for example, an extrusion channel 8 which is a space that communicates between the inlet 6c of the die plate 3 and the extrusion port 2a of the rubber extruder 2. As shown in FIG. Desirably, the extrusion channel 8 includes a confluence portion 8a where the first rubber G1 and the second rubber G2 join. Such an extrusion channel 8 can smoothly merge the first rubber G1 and the second rubber G2.

The preformer 4 includes, for example, a first base preformer 4A on the die plate 3 side, a second base preformer 4B on the rubber extruder 2 side, and between the first base preformer 4A and the second base preformer 4B. and a preformer main body 4C arranged in the . A confluence portion 8a of the extrusion flow path 8 is desirably provided in the preformer main body 4C. Such a preformer 4 is easy to maintain, and its components can be commonly used, so that the production cost can be reduced.

The length L5 of the extrusion channel 8 of the preformer 4 in the second axial direction b on the die plate 3 side is approximately the length L1 (shown in FIG. 3) of the inlet 6c of the die plate 3 in the second axial direction b. preferably equal. Such a rubber extrusion device 1 can efficiently flow the rubber G, and can improve productivity.

FIG. 4 is an enlarged cross-sectional view of the die plate 10 of another embodiment. As shown in FIG. 4, the die plate 10 of this embodiment, like the die plate 3 described above, includes a plate body 11 having a first surface 11a and an opposite second surface 11b.

The plate body 11 has an inlet 11c for receiving the rubber G, a discharge port 11d for discharging the rubber G in a finished cross-sectional shape, and the inlet 11c and the discharge port 11d. It is desirable to have a rubber channel 12 which is a space for The inlet 11c of this embodiment opens on the first surface 11a side. The ejection port 11d of this embodiment opens on the second surface 11b side.

The rubber channel 12 of this embodiment includes a channel narrowing portion 12a in which the length L6 in the second axial direction b decreases from the inlet 11c toward the outlet 11d in a cross section orthogonal to the first axial direction a. contains. It is desirable that the narrowed passage portion 12a be formed over the entire range in the first axial direction a, like the narrowed passage portion 7a described above.

Such a die plate 10 can smoothly flow the rubber G in the rubber flow path 12, and can smooth the surface of the extruded rubber member Gm even when the rubber G is extruded at high speed. Therefore, the die plate 10 of this embodiment can also improve the productivity of rubber extrusion molding.

In the cross section orthogonal to the first axial direction a, the rubber channel 12 of this embodiment has a constant channel portion 12b on the discharge port 11d side of the channel contracted portion 12a and having a constant length L7 in the second axial direction b. contains. The length L8 in the third axial direction c of the channel-identical portion 12b is preferably 25% or more of the distance L9 between the first surface 11a and the second surface 11b. Such a channel-identical portion 12b can improve the accuracy of the finished cross-sectional shape of the rubber member Gm.

A rear chamfered portion 12c is provided between the narrowed passage portion 12a and the same passage portion 12b in this embodiment. It is desirable that the back chamfer 12c is formed over the entire range in the first axial direction a. Such a rear chamfer 12c can suppress the rubber G from being caught in the rubber channel 12, and can smooth the surface of the rubber member Gm that is pushed out even when the rubber G is pushed out at high speed.

The back surface chamfer 12c is, for example, an arcuate chamfer. The length L10 of the back chamfer 12c in the third axial direction c is preferably 5% to 15% of the distance L9 between the first surface 11a and the second surface 11b. Such a rear chamfered portion 12c can achieve both the precision of the finished cross-sectional shape of the rubber member Gm and the productivity of rubber extrusion molding.

A front surface chamfer 14 is provided between the same channel portion 12b and the second surface 11b of this embodiment. The front surface chamfer 14 is preferably formed over the entire range in the first axial direction a. Such a surface chamfer 14 can suppress the rubber member Gm discharged from the discharge port 6d from being caught, and can smooth the surface of the rubber member Gm that is pushed out even when the rubber G is pushed out at high speed. .

The front surface chamfer 14 is, for example, an arcuate chamfer. The length L11 of the surface chamfer 14 in the third axial direction c is preferably 5% to 15% of the distance L9 between the first surface 11a and the second surface 11b. Such a front chamfer 14 can achieve both the accuracy of the finished cross-sectional shape of the rubber member Gm and the productivity of rubber extrusion molding.

Although the particularly preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments and can be modified in various ways.

2 rubber extruder 3 die plate 6 plate body 6a first surface 6b second surface 6c inlet 6d outlet 7 rubber channel 7a channel contraction

Claims (7)

A die plate for a rubber extruder, comprising:
a plate body having a first surface facing the rubber extruder and a second surface opposite thereto;
The plate body is open on the first surface side and has an inlet for receiving rubber from the rubber extruder, and is open on the second surface side and discharges the rubber in a finished cross-sectional shape. and a rubber channel that is a space that communicates the inlet and the outlet,
In a front view of the first surface, the inlet is an elongated opening that is long in the direction of the first axis and short in the direction of the second axis perpendicular to the direction of the first axis,
The rubber flow path includes a flow path narrowing portion whose length in the second axial direction decreases from the inlet toward the outlet in a cross section orthogonal to the first axial direction, and including a channel identical portion with a constant length of
The flow passage narrowing portion is formed over the entire range in the first axial direction ,
A rear side chamfer is provided between the reduced flow path portion and the same flow path portion,
The back chamfer is formed over the entire range in the first axial direction ,
Die plate. In the cross section perpendicular to the first axial direction, the length of the same flow path portion in the third axial direction perpendicular to the second axial direction is 25% or more of the distance between the first surface and the second surface. The die plate of claim 1 , wherein: The die plate according to claim 1 or 2 , wherein the back chamfer is an arcuate chamfer. 4. The die plate according to any one of claims 1 to 3, wherein a chamfered portion on the front side is provided between the same passage portion and the second surface. The plate body includes a first plate provided on one side in the second axial direction and a second plate provided on the opposite side,
The die plate according to any one of claims 1 to 4, wherein said second plate has a rectangular parallelepiped shape . A rubber comprising the die plate according to any one of claims 1 to 5, the rubber extruder provided with an extrusion port for extruding the rubber, and a preformer connecting the die plate and the rubber extruder An extrusion device,
The preformer has an extrusion channel that is a space that communicates the inlet and the extrusion port,
The length of the extrusion channel on the die plate side in the second axial direction is substantially equal to the length of the inlet in the second axial direction,
Rubber extrusion equipment. The rubber extruder includes a first rubber extruder for extruding a first rubber and a second rubber extruder for extruding a second rubber,
7. The rubber extrusion device according to claim 6 , wherein said extrusion flow path includes a confluence portion for merging said first rubber and said second rubber.

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