JPH05104605A - Manufacture of weatherstrip - Google Patents

Abstract

PURPOSE:To obtain a highly accurate weatherstrip having various forms and moreover a length of a part continued to a sealed part is changed at a fixed width, by a method wherein back pressure of an elastomer material of a viscous elastomer material within an extruding machine is detected and the number of revolutions of a screw is allowed to correspond to the back pressure. CONSTITUTION:This is a process manufacturing a weatherstrip wherein a molded body is extruded through product openings 1a, 1b of a mouthpiece for extrusion of the tip of an extrusion machine, opening areas of the product openings 1a, 1b are controlled by a sliding member 3 by corresponding to a change of a width of a weatherstrip, back pressure of a viscous elastomer material directly before extrusion, which is generated by a control change of the opening area by sliding of the sliding member 3, is detected, and a sending-out rate of the elastomer is controlled by adjusting the number of revolutions of a screw of the extruding machine by the back pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an automobile weatherstrip, and more particularly to an automobile having a weatherstrip in a shape having a seal portion at its tip, in which the length of a portion continuous to the seal portion is changed by a constant width. The present invention relates to a method suitable for manufacturing a weather strip for use.

[0002]

2. Description of the Related Art Conventionally, in a method of manufacturing a weather strip, as a method of changing the cross section of an extruded product on the way, (1) the extrusion discharge rate is changed by changing the rotation speed of the extrusion screw, and the similar deformation of the longitudinal cross section is performed. (Japanese Patent Application Laid-Open No. 3-1922), (2) a method in which a movable part is installed as an accessory in the extrusion die and the cross-section of the die outlet is changed by moving the movable part (Japanese Patent Laid-Open No. 59-
(114040 gazette), (3) A method of dividing an extruded body immediately after the exit of an extrusion die into a product shape and a surplus by providing a second movable die (JP-A-61-230930), (4) ) A method is known in which, after the mouthpiece exits, a knife is used to continuously cut a part to change.

[0003]

However, the method (1) cannot change the partial cross section because the extruded cross section changes to a similar shape in the longitudinal direction. In the method (2), although it is possible to change a part of the cross section, other than the cross section in which the change of the cross-sectional area of the die outlet affects the change of the back pressure in the extruder pushed by the screw. There is a problem that the desired shape cannot be obtained due to the change of the die swell in the part that is not desired to change.

Further, the method (3) mechanically divides the tab extruded immediately after the outlet of the die, so that the pressure inside the extruder acts unevenly on the dividing boundary, and the dividing surface does not form a smooth surface. , There is a concern that the product value of the product will be reduced, and there is a restriction on the shape to be changed, especially the shape with a thin tip seal part or the shape with a hollow part in the tip seal part cannot be used. There is a problem that the field is limited.

In the method (4), after extrusion, a product that expands or contracts in the longitudinal direction of the product cannot always be controlled to have a constant cross-sectional area. In particular, products that are extruded with a cored bar are limited to the manufacture of products that do not expand and contract in the length direction, and the knife used for cutting is expected to wear and deform, and there is also a problem in maintenance. There is a drawback that the tip part can be changed in the cross section of the product, but the middle part of the cross section can not be changed, and each of the above-mentioned methods is in terms of manufacturing a wide range of weather strips whose width changes in the longitudinal direction. There was room for improvement.

The present invention addresses the above-mentioned situation, and pays particular attention to the back pressure before the viscous elastomer material in the extruder extruded from the screw is discharged through the extrusion die, and the screw rotation speed is adjusted. Corresponding to this, the tip has a seal part, and the tip seal part has various shapes such as a thin seal lip, a bent seal lip, and a seal lip having a hollow part, and is continuous with the seal part. It is an object of the present invention to accurately obtain a weather strip in which the length of the above-mentioned portion is changed with a constant width.

[0007]

That is, the feature of the present invention for achieving the above object is that the weather strip whose width changes in the length direction is based on the adjustment of the back pressure before the discharge in the extrusion die. In manufacturing, the molded product is extruded through the product opening of the extrusion die at the end of the extruder, and the sliding member adjusts the opening area of the product opening according to the width change of the weather strip, and slides. Detecting the back pressure of the viscous elastomer material immediately before extrusion caused by the adjustment change of the opening area due to the sliding of the member, and adjusting the screw rotation speed of the extruder by the back pressure to adjust the discharge rate of the elastomer. There is a way to adjust.

[0008]

In the method of the present invention as described above, when the sliding member is manually, mechanically, or electrically moved to change the cross-sectional area of the product opening into a predetermined cross-sectional shape, the sliding member is extruded by the screw in the extruder. The back pressure of the coming viscoelastic body, that is, the viscous elastomer material before discharge changes. Therefore, this change in back pressure is detected by a pressure sensor installed in advance. The detected change in back pressure is immediately sent to the control device, which then sends it to the rotation speed control device of the screw of the extruder to adjust the rotation speed and adjust the discharge amount from the extrusion die. That is, when the product opening area moves in the decreasing direction by the sliding member, the back pressure in the extruder immediately before the extrusion of the product opening part usually increases, and the shape of the extruded product increases due to the die swell. Although the accuracy cannot be obtained, in the present invention, the screw rotation speed is reduced, the elastomer material that responds to the shape change is delivered to the product opening, the discharge pressure is made uniform, the fluctuation of the die swell is eliminated, and the accuracy of the product shape is secured. To do.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the accompanying drawings. 1 and 2 show an example of an apparatus for carrying out the method of the present invention, particularly an extruder forming the essential part thereof. In the drawings, the head portion (2) of the extruder forms a weatherstrip having a predetermined cross-sectional shape. Therefore, a die plate (1) having product openings (1a), (1b) having a predetermined cross-sectional area, and a sliding member (3) slidably arranged on the extrusion side front surface of the die plate (1). And a surface plate (4) is attached to the surface thereof to form an integral body.

In the mouthpiece having the above-mentioned structure, in the present invention, the pressure sensor (5) further penetrates the inside of the mouthpiece plate (1) and the tip of the pressure sensor (5) opens the product opening (1) of the mouthpiece plate (1).
The pressure sensor (5) is installed so as to face a), and the pressure sensor (5) is connected to the control device (6) and transmits the pressure change of the portion detected by the pressure sensor (5) to the control device (6). At the same time, the control device (6) is connected and connected to the screw rotation speed control device (7), and the screw (not shown) of the extruder (8) is connected via the control device (7) according to the transmitted pressure change. No.) to adjust the discharge rate by adjusting the rotation speed of the screw. In the figure, (9) is an actuating part of the sliding member (3), which may be artificial, mechanically or electrically actuated. Further, (10) is a molding core attached to the sliding member, which is used when the sealing portion lip of the weatherstrip product to be extruded is hollow (3).
The core is fixed with a bridge.

Thus, when manufacturing a weather strip for an automobile using the above-mentioned mouthpiece, in order to simplify the explanation in the above description, single extrusion of only one elastomer material is explained. , As is known, send solid elastomer material from one extruded material,
The expandable elastomer material is fed from the other extruder, the seal portion is formed of the expandable elastomer, and the attachment portion continuous to this is formed of solid elastomer. However, the weather strip to be molded is usually not the same width in the longitudinal direction as shown in FIG. 3, but continuously extruded,
The width changes along the way.

Then, when the sliding member (3) is moved by the operating part (9) in order to match the cross-sectional areas of the product openings (1a), (1b) with a predetermined cross-sectional shape, it is extruded from the extruder. In the viscous elastomer material, the back pressure changes due to the change of the opening area, and the pressure sensor (5) detects this and transmits it to the screw rotation speed control device (7) via the control device (6). Become.

At this time, the screw rotation speed is determined by the product opening (1
a) and (1b) are adjusted according to the opening area, and when the product opening area decreases due to the reduction of the width of the weatherstrip product, the screw rotation speed is decreased to reduce the feed and increase the back pressure. It is possible to alleviate and uniformize the discharge pressure to the product openings, eliminate the fluctuation of the die swell, and accurately shape the weatherstrip in a predetermined shape.

FIGS. 4A, 4B and 4C show examples of weather strips obtained by the method of the present invention as described above.

[0015]

As described above, according to the present invention, in manufacturing a weather strip whose width changes in the longitudinal direction, the width of the weather strip is changed by pressing the molded body through the product opening of the extrusion die at the tip of the extruder. Corresponding to the above, the opening area of the product opening is adjusted by the sliding member, and the back pressure of the viscous elastomer material just before extrusion which is caused by the change in the opening area due to the sliding of the sliding member is detected. However, the screw rotation speed of the extruder is adjusted based on the back pressure to adjust the delivery ratio of the elastomer material, and by adjusting the material delivery amount by the screw according to the change of the product opening area, In the normal case, if the product aperture becomes smaller according to the screw diameter feed, a large back pressure will be generated in the viscous material that has been extruded, and the die swell will be created at the product aperture due to the principle of streamline convergence. It also affects the cross-sectional area and adversely affects the product shape, but by adjusting the delivery amount with the screw, the discharge pressure and back pressure to the product opening are always kept constant and the delivery amount to the product opening is appropriate. There is a remarkable effect that the accuracy of the product shape can be secured and improved by controlling the die swell without fluctuation. Moreover, according to the method of the present invention, there is no restriction on the shape for changing the product as in the conventional methods, and the shape of the tip seal portion contacting the panel side of the automobile is a thin lip, a bent lip, or a hollow lip. It is possible to easily change the length of a part continuous to the seal portion, and its application range is wide.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an example of an extruder head portion used for carrying out the method of the present invention.

2 is a schematic perspective view of the extrusion die of FIG. 1. FIG.

FIG. 3 is an explanatory view showing a changed state of a weather strip manufactured by the present invention.

FIG. 4 shows a weatherstrip manufactured according to the present invention,
(A), (B), (C) are representative examples.

[Explanation of symbols]

 (1) Die plate (1a) (1b) Product hole (2) Extruder head (3) Sliding member (5) Pressure sensor (6) Control device (7) Screw rotation speed control device (8) Extruder

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number FI Technical display location // B29L 31:30 4F (72) Inventor Kaizo Yoshioka Miyoshi-cho, Nishikamo-gun, Aichi Prefecture Ichiga Yama No. 3 Toyo Tire & Rubber Co., Ltd. Automotive Parts Technology Center

Claims (1)

[Claims] 1. A method of manufacturing a weather strip having a width varying in the length direction, wherein a molded body is extruded through a product opening of an extrusion die at the tip of an extruder, and a sliding member corresponding to the width variation of the weather strip. By adjusting the opening area of the product opening by detecting the back pressure of the viscous elastomer material immediately before extrusion caused by the adjustment change of the opening area due to the sliding of the sliding member, and based on the back pressure. A method of manufacturing a weather strip, which comprises adjusting the screw rotation speed of the extruder to adjust the delivery rate of the elastomer material.