JPH06270197A - Molding method for molding part of weatherstrip - Google Patents

Abstract

PURPOSE:To mold a molding part having excellent sealability without wrinkle on a surface of an end of a sealed part of sponge rubber when the part is molded at an end of an extrusion molded weatherstrip having the sealed part of the rubber. CONSTITUTION:An end of an extrusion molded weatherstrip 1A having a base part 11 of solid rubber and a sealed part 12 of sponge rubber is inserted into an end of a cavity 30 of a mold, and a draw part 31 made of a protrusion 32 partitioned by a groove 33 is formed at a position immediately before an inserted end of the part 12 at the end of the cavity 30. A molding material is injected in the cavity, a molded material reduced under pressure through the part 31 is supplied to the end of the part 12, a rib 16 is formed by the groove 33 at a thin part 15 of a product generated by the part 31 to reinforce the part 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of molding a weather strip molding portion, and more particularly, to the molding of solid rubber at the end of an extrusion weather strip comprising a solid rubber portion and a sponge rubber portion. The present invention relates to a method of molding a part.

[0002]

2. Description of the Related Art An example of a weather strip having a molding portion of this type is an automobile door weather strip.

In an automobile as shown in FIG. 3, the door frame 5 and the door glass 6 are provided inside the door frame 5.
A door weather strip 1 is attached which seals between the peripheral edges of the.

FIG. 4 shows a corner portion (A portion in FIG. 3) of the door weather strip 1. The corner portion is a molding portion 1C for connecting the ends of two weather strips 1A and 1B formed by extrusion molding. It is composed by. Weather strip 1A
Is a solid rubber base 11, a sponge rubber seal 1
2 and a hollow portion 14 provided with a sponge rubber seal portion 13. The entire weather strip 1B is solid rubber.

In general, in order to mold the die molding section 1C,
The two weather strips 1A and 1B are inserted into both ends of the cavity of the mold so that the ends of the two weather strips 1A and 1B face each other at substantially right angles.
A solid rubber slightly softer than the solid rubber is injected to form a mold forming portion 1C having substantially the same cross-sectional shape on both sides as the weather strips 1A and 1B.

However, the sponge rubber seal portion 12,
Since 13 is extremely soft, its end is pushed by the injection pressure of the injection material of solid rubber, and the seal part 1 is attached to the product.
Ripples occur at the ends 2 and 13, especially at the ends of the seal portion 12.
This corrugation may deteriorate the sealing property of the seal portion 12 and spoils the appearance.

As a means for preventing the occurrence of this waviness,
A means for lowering the injection pressure of the injection material can be considered, but if the injection pressure is decreased, the material will not easily turn to every corner of the cavity. On the other hand, it is conceivable to use sponge rubber for the entire molding portion, but in this case, the above-mentioned waviness due to material injection does not occur, but the holding force of the molding portion with respect to the door frame becomes weak.

Therefore, the inventor firstly found that at the end of the cavity into which the end of the weather strip 1A for extrusion molding is inserted,
A protrusion is provided at a position just before the end of the seal portion 12 to form a narrowed portion, which is injected into the cavity and then the weather strip 1A.
A molding method has been developed in which only the material reaching the end of the seal portion 12 is squeezed out of the molding material reaching the end of the seal portion 12, and the pressing pressure on the end surface of the seal portion 12 is lower than the pressing pressure on the end surface of the base portion 11. (JP-A-3-248819).

According to this molding method, it is possible to prevent the above waviness from occurring at the end portion of the seal portion 12 of the weather strip 1A. However, on the other hand, by providing the narrowed portion in the cavity, as shown in FIG. 4, the thin portion 15 is formed in the seal portion 12c of the mold forming portion 1C at a position corresponding to the narrowed portion. The thin portion 15 has a smaller reaction force against the pressing of the door glass than the other portions, and causes the sealing property to deteriorate, though not so much as the deterioration of the sealing property due to the corrugation.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and uses a metal mold having a narrowed portion for preventing the occurrence of the corrugation, and has a sealing property of a thin portion produced in a product. It is an object of the present invention to provide a molding method of a weatherstrip mold forming section which is improved.

[0011]

As shown in FIG. 2, the present invention includes a cavity 30 for inserting an end of an extrusion-molded weather strip 1A having a solid rubber base 11 and a sponge rubber seal 12. Throttle portion 31 provided with a protruding portion 32 partitioned by a groove 33 immediately before the insertion end of the seal portion
Is formed, the molding material of solid rubber is injected into the cavity 30, and the molding material whose pressure is reduced through the narrowed portion is supplied to the end of the seal portion.

[0012]

Of the molding material injected into the cavity 30, the material flowing to the end of the seal portion 12 is squeezed by the squeezing portion 31, diffuses out of the squeezing portion 31, and diffuses.
To the terminal. Therefore, the pressure of the material acting on the end surface of the seal portion 12 is reduced, and the end portion of the seal portion 12 is not corrugated. Also, the seal portion 12c of the product molding portion 1C
The portion corresponding to the narrowed portion 31 becomes the thin portion 15, and the thin portion 15 is provided with a rib 16 which crosses the thin portion 15 corresponding to the groove 33 of the narrowed portion 31. Therefore, a sufficient reaction force for pressing the door glass is secured.

[0013]

1 and 2 show an embodiment in which the present invention is applied to a door weather strip, and FIG. 1 is a perspective view of a corner portion (A portion in FIG. 3) formed by a molding portion, Figure 2
FIG. 2A is a perspective view of a main part of FIG. 1, and FIGS. 2B and 2C are cross-sections at the time of molding at positions along the lines BB and CC of FIG. 2A, respectively. It is a figure.

The door weather strip 1A is an extruded body having a U-shaped cross section and a base 11 in which a core metal 10 is embedded.
And a lip-shaped seal portion 12 protruding from the lower end side surface of the base portion 11, and a hollow portion 1 protruding from the open end side surface of the base portion 11.
4 and the wall 13 of the hollow portion 14 forms a sealing portion. The seal portions 12 and 13 are made of sponge rubber, and the base portion 11 and the hollow portion 14 other than the seal portion 13 are made of solid rubber. On the other hand, the entire door weather strip 1B is an extruded body of solid rubber.

The mold forming portion 1C for connecting the door weather strips 1A and 1B to form a corner portion is made of a solid rubber softer than the solid rubber of the door weather strips 1A and 1B, and has an L-shape as a whole. The door weather strip 1A side is bent, and the door weather strip 1A side has substantially the same cross-sectional shape, and the door weather strip 1B side has substantially the same cross-sectional shape.

To mold the mold molding portion 1C, the ends of the door weather strips 1A and 1B are placed at both ends of the mold cavity, and a solid rubber molding material is injected from a gate opening at the center of the cavity. .

As shown in FIGS. 2B and 2C, the mold 3
The cavity 30 is provided with a throttle portion 31 for narrowing the flow rate of the molding material flowing to the seal portion 12 at a position just before the seal portion 12 at the end portion into which the end of the door weather strip 1A is inserted. The narrowed portion 31 is provided on the back surface side, and is formed by a plurality of protruding portions 32 partitioned by a groove 33 in a direction intersecting with the material flow direction. The shape of the groove 33 may be U-shaped, V-shaped or the like, and a plurality of grooves 33 may be formed.

When molding material is injected from the gate into the cavity 30 during molding of the molding portion 1C, the material flows to the ends of both door weather strips 1A and 1B. At this time, on the door weather strip 1A side, the molding material reaching the seal portion 12 is squeezed by the squeezing portion 31 immediately before the end of the seal portion 12, and then diffuses to reach the end of the seal portion 12. For this reason,
The pressing force of the material acting on the seal portion 12 becomes lower than that of the other portions. Therefore, the end of the sponge rubber seal portion 12 is not largely pushed in, and waviness as in the conventional case does not occur.

Sealing portion 12c of molded portion 1C
As shown in FIGS. 1, 2 (A) and 2 (C), a thin portion 15 formed by the narrowed portion 31 of the cavity 30 is formed on the back surface side of the. However, the thin portion 15 has ribs 16 that cross it. Therefore, when the peripheral edge of the door glass is pressed against the thin portion 15, a sufficient reaction force is obtained by the rib 16 and the same sealability as the general portion of the seal portion 12 or the seal portion 12c is obtained.

Although the seal portion 13 of the door weather strip 1A is made of sponge rubber,
Unlike the seal portion 12, both ends are connected to the solid rubber portion. Therefore, even if it receives the injection pressure of the molding material, it is less pushed in, and the occurrence of waviness is less. However, even in this portion, the occurrence of waviness can be further reduced by using the same means as described above.

The embodiment of the door weather strip mounted on the door frame has been described above. However, the present invention is not limited to the door weather strip, and is made by extrusion molding including a solid rubber base and a sponge rubber seal. It can be widely applied when connecting a solid rubber molding part to a weather strip.

[0022]

According to the present invention, a sponge rubber can be obtained by supplying a molding material through a narrowing portion when connecting and molding a die molding portion to an extrusion weatherstrip part of which is made of sponge rubber. Prevents the generation of wavy wrinkles
Moreover, by providing the groove in the narrowed portion, it is possible to prevent the sealing property of the thin portion of the product from being deteriorated.

[Brief description of drawings]

FIG. 1 is a perspective view of a mold forming portion of a weather strip formed according to the present invention.

2 (A) is an enlarged view of a main part of FIG. 1, and FIG. 2 (B) is a cross-sectional view of a mold at the time of mold molding taken along line BB of the main part of FIG. 2 (A). 2 (C) is a cross-sectional view of the main part of FIG. 2 (A) taken along the line C-C during mold forming.

FIG. 3 is a side view of an automobile in which a weather strip is mounted around a door.

FIG. 4 is a perspective view of a conventional mold forming portion of a weather strip.

[Explanation of symbols]

 1A, 1B Extrusion Molding Weather Strip 1C Mold Molding Part 11 Bases 12, 13 Sealing Part 15 Thin Wall Part 16 Thin Wall Rib 3 Mold 30 Cavity 31 Throttling Part 32 Projecting Part 33 Groove

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Claims (1)

[Claims] 1. An extruded weather strip end composed of a solid rubber mounting base and a sponge rubber seal is inserted into an end of a cavity of a mold, and a solid rubber molding material is placed in the cavity. In a method of injecting and molding a die-molded portion having substantially the same cross-sectional shape as the weather strip at the end of the weather strip, the sealing portion of the extrusion-molded weather strip is provided at the end of the cavity. Immediately before the insertion end of, a plurality of protrusions partitioned by grooves are provided to form a narrowed portion, and a material reaching the end of the seal portion of the molding material injected into the cavity
A method for molding a die-molded portion of a weather strip, characterized in that the pressure is reduced through the narrowed portion and supplied to the end of the seal portion.