JP3521133B2 - Manufacturing method of weather strip for seal hood - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a weather strip for a seal hood. 2. Description of the Related Art As shown in a perspective view of an automobile shown in FIG. 1, a front end portion of a cowl panel 2 provided so as to cover an upper portion of a cowl is pressed against a rear lower surface of a hood 3. In order to seal a gap between the hood 3 and the vehicle body, a weather strip 1 for a seal hood (hereinafter, may be simply referred to as a weather strip) is attached. Conventionally, a rubber foam has been used as a material for forming the weather strip. [0003] However, recent trends in the development of automobiles include low price, low weight, and recyclability. However, these problems have been achieved by using a rubber foam. There was a limit. [0004] It is an object of the present invention to provide a weather strip for a seal hood, which has achieved lower cost, lower weight and recyclability than the conventional one. In order to achieve the above object, a weather strip for a seal hood according to the present invention is provided .
The manufacturing method is formed of a thermoplastic elastomer foam, includes a mounting base attached to the vehicle body, and a hollow seal portion pressed against the lower surface of the bonnet, and a cross-sectional shape of the mounting surface of the mounting base is A weather strip for a seal hood in which protrusions having a shape protruding from the center are formed at both ends of the center, and the center and the protrusions at both ends are connected by a gentle curve.
In the manufacturing method, the protrusion of the extrusion molding die
Heat the part to be formed to 200 ° C to 220 ° C, otherwise
Set the temperature between + 15 ° C and + 40 ° C for the part
It is characterized by the following. Manufactured by the manufacturing method according to the present invention.
Weather strip for seal hood that can be made
Are as follows. When the weatherstrip is formed from a rubber foam, the specific gravity is about 0.65, and when the weatherstrip is formed from a thermoplastic elastomer foam, it is about 0.5. Therefore, it is possible to achieve a weight reduction of about 15% as compared with the related art. In addition, since thermoplastic elastomers can be molded and processed by a plastic molding apparatus, products can be manufactured without a kneading step and a vulcanizing step, and thus are superior in cost as compared with rubber foams. Further, the thermoplastic elastomer foam is superior to the rubber foam in terms of recyclability. As described above, by using a thermoplastic elastomer foam, it is possible to provide a weather strip for a seal hood which has achieved low cost, low weight and recyclability. [0008] The weather strip for a seal hood includes a mounting base for mounting to a vehicle body and a hollow seal portion pressed against the lower surface of the bonnet, and a cross-sectional shape of the mounting surface of the mounting base is centered. Because both ends are formed in a shape that protrudes more than the part, when the weather strip is attached, the surface pressure is stronger at both ends than at the center of the mounting surface and the sealing effect can be enhanced. it can. Furthermore, as a specific configuration in which both ends protrude from the center, projections are formed at the both ends, so that when the weather strip is attached,
By deforming the projection, a desired sealing property can be secured. [0010] The weatherst for a seal hood according to the present invention.
The method for manufacturing the lip is for manufacturing the weather strip for the seal hood described above , and the feature thereof is that the portion for forming the protrusion of the extrusion molding die is
The other part is heated to + 15 ° C to + 40 ° C. At a normal temperature setting, the projections are in a state of being crooked, and the sealing performance is reduced. By setting the heating temperature as described above, the surface state of the projections becomes smooth, and good sealing properties can be secured. An embodiment of a weather strip for a seal hood according to the present invention will be described with reference to the drawings. <First Embodiment> FIG. 1 is a perspective view of an automobile, in which a cowl panel 2 provided so as to cover an upper part of a cowl has a front end portion pressed against a rear lower surface of a bonnet 3. Then, a weather strip 1 for a seal hood is attached to seal a gap between the hood 3 and the vehicle body. The weatherstrip 1 extends longitudinally along the front end. Weather strip 1
It is formed by a thermoplastic elastomer foam. The following can be used as the thermoplastic elastomer (hereinafter referred to as TPE). That is, styrene-butadiene-styrene block copolymer (SB) is used as polystyrene-based TPE (SBC).
S), styrene-isoprene-styrene block copolymer (SIS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene-styrene block copolymer (SE)
PS) and the like, and the polyolefin-based TPE (TPO) includes a simple blend type (s-TPO), an implanted TPO (i-TPO), a dynamic vulcanization type (TPV), and the like. In each case, polypropylene (PP) or polyethylene (PE) is mainly used for the hard segment, and EPDM, NBR, etc. are mainly used for the soft segment. The polydiolefin-based TPE includes syndiotactic-1,2 polybutadiene (RB) -based TPE.
PE, trans-polyisoprene (TPI) -based TPE, natural rubber-based TPE (TPNR), and the like. The chlorine-based TPE is a polyvinyl chloride-based TPE, ie, a PVC-based TPE (TP
VC), chlorinated polyethylene and the like. Further, engineering plastic type TPE, polyurethane type (TPU) TPE, polyester type (TPEE) TP
E, polyamide-based (TPA) TPE, fluorine-based TPE, and the like. In an extruder for producing the weather strip 1, a polyolefin-based TPE is used in that a good foam can be formed using water which is a foaming agent having no environmental problem. It is particularly preferable to use a polyolefin-based TPE in which a vulcanized rubber such as butyl rubber, isoprene rubber, EPDM, natural rubber, butadiene rubber, or SBR is dispersed in PP or the like in the form of particles. FIG. 2A is a sectional view of the weatherstrip 1 taken along a plane perpendicular to the longitudinal direction. The weatherstrip 1 includes an attachment base 1 a attached to the cowl panel 2, and a hollow seal portion 1 b that is pressed against the lower surface of the rear end of the bonnet 3 and deforms. The central portion 1c and the pair of projecting portions 1d at both ends are connected by a gentle curve. As shown in FIG. 2, the weather strip 1
Mounting clips 4 at predetermined intervals along the longitudinal direction of the
Is provided. This clip 4 is a well-known one, and has a head 4a inserted into the hollow seal portion 1b,
Collar 4b for holding base 1a in cooperation with head 4a
And a retaining portion 4c for preventing the weather strip 1 from coming off when the clip 4 is inserted into the hole formed in the cowl panel 2. Also, the mounting base 1 of the weather strip 1
a, a central portion 1c having a flat shape on the mounting side with respect to the cowl panel 2 and a pair of protrusions 1d formed at both ends of the central portion 1c. FIG. 2B is an enlarged view of the protrusion 1d, and the radius R of the tip is 0.75 mm.
Below (1.5 mm or less in diameter), and the height H is 1.5
mm or less. If the radius R of the tip is increased, the surface pressure acting on the protrusion 1d is reduced and the sealing performance is also reduced. Therefore, it is desirable that the radius R of the tip be 0.75 mm or less. Further, the height H is desirably 1.5 mm or less. If the height is too high, the rigidity of the projection 1d also decreases, and the desired sealing property cannot be secured. However, the height of the clip 4 must be equal to or higher than the flange 4b. When the weather strip 1 is manufactured by the TPE in which the above-mentioned vulcanized rubber is dispersed, the temperature of the cylinder of the extruder is usually adjusted to 170 to 180 ° C. and the temperature of the head and the die to 180 to 185 ° C. The weather strip 1 having a desired shape can be manufactured by press-injecting water near the center of the portion and foaming at the same time as extrusion. At this time, the protrusion 1d of the extrusion die is used.
Is formed at 200 ° C. to 2 ° C. with a heat source such as a sheath heater.
20 ° C. (+15 to +40 with respect to a portion other than the protrusion 1d)
° C; +20 to + 50 ° C with respect to the cylinder). When the temperature is set to 190 ° C. or lower, the protrusion 1d is in a state of being squeezed, and the sealing property is reduced. 20
By setting the temperature to 0 ° C. or higher, the surface state of the projections becomes smooth, and good sealing properties can be secured. FIG. 3 is a view showing a state in which the weather strip 1 is mounted on the mounting surface 2 a of the cowl panel 2.
Attach the clip 4 to the mounting surface 2a of the cowl panel 2.
This is performed by inserting it into the hole formed in the hole. Clip 4
Of the hole formed in the mounting portion 2a of the cowl panel 2, and the weather strip 1 is mounted so as not to come off. In the mounted state, the protrusion 1d is deformed, so that the sealing property is ensured.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an automobile. FIG. 2 is a cross-sectional view of a weather strip according to an embodiment cut along a plane orthogonal to a longitudinal direction. FIG. [Description of reference numerals] 1 Weather strip 1a Mounting base 1b Hollow seal portion 1c Central portion 1d Projection 2 Cowl panel 3 Bonnet 4 Clip H Height R Radius

Continuation of the front page (51) Int.Cl. ⁷ identification code FI B29K 105: 04 B29L 31:30 B29L 31:30 B60J 5/00 501G (58) Investigated field (Int.Cl. ⁷ , DB name) B60R 13 / 06 B29C 47/78

Claims (1)

(57) The present invention is characterized in that it comprises a mounting base portion formed of a thermoplastic elastomer foam and mounted to a vehicle body, and a hollow seal portion pressed against a lower surface of the bonnet, The cross-sectional shape of the mounting surface of the mounting base is formed at both ends of the central portion with protrusions having a shape protruding from the central portion, and
In the method for manufacturing a weather strip for a seal hood, wherein the projections at the central portion and the projections at the both end portions are connected by a gentle curve, the projections of an extrusion molding die are provided.
Is heated to 200 ° C to 220 ° C.
Set the temperature between + 15 ° C and + 40 ° C for the outer part
A manufacturing method characterized in that: