JPH058704A - Manufacture of wiper freeze preventing cover and freeze preventing wiper - Google Patents

Abstract

PURPOSE:To manufacture a freeze preventing cover of a wiper blade at low cost with a cycle time shortened and a fraction defective lowered, and improve coupling property between the freeze preventing cover and a brade rubber. CONSTITUTION:A cylindrical member 7 of a freeze preventing cover 5 is formed by blow molding of thermal plastic elastomer as a material, and a blade rubber insertion groove part 5a of the cylindrical member is molded by using a molding die 10 and also by heating the molding die. The base surface part of a blade rubber 4 is molded of the same material as that of the freeze preventing cover 5, and the base part of the blade rubber 4 is inserted in a groove part 5a of the freeze preventing cover to be heat-welded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifreezing cover for a wiper blade fitting, which protects a vehicle wiper blade from snow and freezing in cold regions and prevents its function from deteriorating.

[0002]

2. Description of the Related Art In order to protect a wiper blade from snow and freezing, the entire wiper blade fitting is covered with a tubular antifreezing cover. The conventional antifreezing cover is made of chloroprene rubber latex, and is manufactured by a method called a die dipping method. The manufacturing is performed, for example, in the following 10 steps. (1)
The surface of a long rod-shaped mold having almost the same length as the wiper blade metal fitting is ultrasonically cleaned to clean dirt deposits. (2) The mold is immersed in a mold release agent tank to facilitate the mold release after molding. (3) Dry the mold. (4) Since latex is solidified and attached to the mold, it is dipped in a coagulant. (5) Dry the coagulant attached to the mold. (6) Immerse the latex attached to the mold in a rubber latex tank. (7) The latex adhering to the mold is dipped in a coagulant to solidify the surface. (8) Wash the solidified latex with water. (9) Add latex to about 1 at 100-150 ° C.
Place in a constant temperature bath for vulcanization. (10) Pull out the latex tubular cover product from the mold.

The latex cover manufactured as described above can be molded to a thin wall thickness of 0.3 to 0.5 mm and has a large physical property. Therefore, the wiper metal fittings rarely affect the change of the windshield,
It was suitable as an anti-freezing cover. When the wiper blade rubber is inserted into the groove portion of the anti-freezing cover manufactured as described above and attached, since no adhesive is used, the water that has entered there freezes and the wiping property deteriorates. The functional decline was remarkable. Bonding with an adhesive is also conceivable, but bonding is not performed because the bonding is non-uniform and strength cannot be obtained, and the bonding process itself is not easy.

[0004]

Molding of the antifreezing cover using the above-mentioned prior art chloroprene rubber latex is as follows.
This is a method called a die dipping method, and since the process is complicated, it requires a lot of equipment cost, die cost, and cycle time. In addition, the workability is poor, and the product cover is torn or deformed during demolding in a complicated process.
There was a drawback that the defective rate was%, resulting in high product cost. To improve the defective rate of the product cover,
In Japanese Patent Application No. 2-405054, a two-layer structure having two materials is proposed, but it is basically a method of immersing a mold in latex, and since the number of steps is increased, it cannot be said to be a significant improvement. Furthermore, the manufacturing cycle is 2 per product cover.
Since it takes a long time, there is a problem in that a large number of molds corresponding to this cycle and the number required for manufacturing must be prepared. As described above, in the conventional method, the number of steps is large, the equipment cost and the space are large, the cycle time at the time of manufacturing is long, and the demolding is manual work, so the workability is poor and the defect rate is high. There was a problem that the cost would be high. Therefore, it is an object of the present invention to shorten the cycle time in the production of the antifreezing cover and reduce the defective rate so that it can be produced at a low cost. It is another object of the antifreezing wiper to improve the bondability between the antifreezing cover and the blade rubber.

[0005]

DISCLOSURE OF THE INVENTION The present invention is a method for manufacturing an antifreezing cover and an antifreezing wiper which achieve the above object. The method for manufacturing the antifreezing cover is to blow mold a tubular member using a thermoplastic elastomer as a material, and press the blade-corresponding groove portion of the tubular member into a molding die corresponding to the blade rubber insertion groove. And, the pressure contact portion is heated to be manufactured. When molding the groove portion for inserting the blade rubber into the tubular member, it is convenient to press the tubular member against the molding die by using a crimping jig or a negative pressure.

As the thermoplastic elastomer for the antifreezing cover manufactured by this manufacturing method, it is flexible and has a large strength that a block copolymer of one of polybutadiene, polyisoprene, polyethylene butylene and polystyrene is used. It is desirable because it has good low-temperature characteristics. Furthermore, if the outer surface of the base of the blade rubber is made of the same material as the anti-freezing cover, and the base is inserted into the groove of the anti-freezing cover and heat-sealed, there is no deterioration in function due to freezing in water, and durable anti-freezing Become a wiper.

[0007]

The anti-freezing cover manufactured by the above manufacturing method has the same material hardness, elongation, strength, and low temperature property as the conventional cover made of chloroprene rubber latex. It is very economical because it can greatly reduce the mold cost, cycle time and defective rate. In other words, the antifreezing cover is manufactured by two steps, that is, blow molding is performed in a shape in which the groove portion into which the blade rubber is inserted is expanded, and then the product cover is heat-molded by being pressed against a molding die, so that the whole is almost uniform. It becomes a thick product with high dimensional accuracy, and there is no chance that the vicinity of the groove will be thinned by molding to the final shape only by blow molding. Further, since the cover product has two steps of blow molding and die molding, the cycle time of production is as short as 1 to 2 minutes per one. Therefore, the number of molds is small and it is economical.

[0008]

Embodiments of the present invention will be described with reference to the drawings. The antifreezing cover manufactured by the manufacturing method of the present invention has the structure shown in FIGS.
It is applied to the vehicle wiper blade shown in. In this wiper blade, the wiper blade metal fitting 2 is attached to the wiper arm 1 by the clip metal fitting 3, and the blade rubber 4 attached to the wiper blade metal fitting 2 is swung by the swing of the wiper arm 1 to wipe the glass surface. It is like this. Then, the entire wiper blade fitting 2 is covered with a long cylindrical antifreezing cover 5, and both ends of the antifreezing cover 4 are closed with resin caps 6 so that the wiper blade fitting 2 does not malfunction due to snow or freezing. ing. The base of the blade rubber 4 is inserted into the groove 5 a formed in the antifreezing cover 5, and the base of the blade rubber 4 is held by the wiper blade fitting 2 via the antifreezing cover 5.

Next, a method of manufacturing the antifreezing cover 4 will be described with reference to FIGS.
This will be described with reference to FIG. A cylindrical member 7 was prepared by blow molding using polyethylene butylene (SEBS material SE6400 grade) manufactured by Mitsubishi Petrochemical Co., Ltd. as a material. In this case, the temperature of the head and die of the blow molding machine was set to 200 ° C, and the mold temperature was set to 60 ° C. Further, the plasticized material (parison) extruded from the blow molding machine is automatically set so that the cylindrical member 7 has a large tube diameter in the central portion, so that the material discharge amount increases in the central portion and the wall thickness and diameter increase a little. Has been done. Then, the extruded parison was clamped and internal pressure was applied to obtain a relatively uniform molded product having a wall thickness of 0.4 to 0.6 mm. Both ends of the obtained molded product are cut to form the tubular member 7 shown in FIG. The tubular member 7 is formed in a state where the groove portion 5a into which the blade rubber 4 is inserted is expanded. That is, in the tubular member 7, the groove portion 7a into which the blade rubber 4 is inserted is in a developed state, and both end portions are small diameter tubes.

Into the tubular member 7 obtained as described above, two crimping jigs 8 having substantially the same length and a long plate-shaped support jig 9 are inserted, and the crimping jig 8 is a tubular member. A part corresponding to the groove portion for inserting the blade rubber of 7 is arranged so as to be in contact with the molding die 10, and the support jig 9 is arranged on the opposite side of the crimping jig 8. Then, the movable crimping jig 8 is pressed against the molding die 10 side to bring the peripheral wall of the tubular member 7 into pressure contact with the molding die 10. At this time, the crimping jig 8 is slid on both sides of the ridge 10a corresponding to the groove 4a of the molding die 10 (arrow in FIG. 4), and a plurality of through holes 10 provided in the ridge 10a are further provided.
The pressure is reduced in vacuum from b, and the peripheral wall of the tubular member 7 is brought into pressure contact with the molding die 10. Further, the molding die 10 is heated to about 150 ° C. (preferably 150 to 170 ° C.) by a heating device (not shown) to form the groove portion 4a into which the base portion of the blade rubber 5 is inserted, and the freeze prevention cover 4 shown in FIG. It was created. In the above embodiment, the crimping jig 8 is used when molding the groove 5a.
Although the molding die 10 and the molding die 10 are used, since the cylindrical member 7 is made of a soft material, the peripheral wall of the cylindrical member 7 is formed only by the negative pressure.
The pressure bonding jig 8 can be pressed against 0, and the pressure bonding jig 8 is not always necessary.

The base portion of the blade rubber 4 is inserted into the groove portion 5a of the antifreezing cover 5 manufactured as described above and attached.
In order to obtain a desirable state for freeze prevention, the configuration is as shown in FIG. By providing a coating layer 4a of the same thermoplastic elastomer as that of the material of the antifreezing cover 5 on at least the outer surface of the base of the blade rubber 4 and inserting the base into the groove 5a of the antifreezing cover 5 for heat welding, The base portion of the blade rubber 4 was bonded inside the groove portion 5 a of the antifreezing cover 5. The wiper blade thus produced has a strong adhesive force between the blade rubber 4 and the antifreezing cover 5, and can prevent functional deterioration or damage caused by water entering the joint portion and freezing.

[0012]

According to the method of manufacturing the antifreezing cover of the present invention, the cover is formed by blow molding into a shape having no groove for inserting the blade rubber, and then the groove is formed by heat molding with a molding die. It is economical because it is possible to accurately manufacture a cover having excellent elongation, strength, and low temperature characteristics, and significantly reduce equipment costs, manufacturing cycle time, and defective rate. Further, the wiper blade in which the blade rubber is heat-welded to the antifreezing cover has a good bonding property between the two, which is desirable for antifreezing.

[Brief description of drawings]

FIG. 1 is a front view of a wiper having an antifreezing cover to which the present invention is applied.

FIG. 2 is a sectional view of a wiper having an antifreezing cover.

FIG. 3 is a front view of a tubular member used for manufacturing an antifreezing cover and a cross-sectional view of two portions.

FIG. 4 is an explanatory view showing a manufacturing process of the antifreezing cover.

FIG. 5 is a front view of the antifreezing cover and a sectional view of two portions.

FIG. 6 is a cross-sectional view showing a state in which a blade rubber is heat-welded to a groove portion of an antifreezing cover.

[Explanation of symbols]

2 Wiper blade bracket 5 Anti-freezing cover 5a groove 7 Cylindrical member 8 Crimping jig 10 Mold

Claims (4)

[Claims] 1. A method of manufacturing an antifreezing cover having a tubular portion covering a wiper blade fitting and a groove portion into which a blade rubber is inserted, wherein a tubular member is formed by blow molding using a thermoplastic elastomer as a material. Forming the blade rubber insertion groove by pressing the blade insertion groove equivalent portion of the obtained tubular member into a molding die having a shape corresponding to the blade rubber insertion groove, and heating the pressure contact portion. A method for manufacturing an antifreezing cover for a wiper, comprising: 2. A through hole for intake is provided at several places corresponding to the groove portion of the blade rubber insertion in the molding die, and the cylindrical member is pressed against the molding die by sucking air through these through holes, and 2. The method for manufacturing the antifreezing cover for the wiper according to claim 1, wherein a crimping jig is placed in the member and pressed against the molding die. 3. An antifreeze cover manufactured by the manufacturing method according to claim 1, wherein the cover is made of a block copolymer of polystyrene with one selected from polybutadiene, polyisoprene, and polyethylene butylene. An anti-freezing cover characterized in that 4. An antifreeze wiper in which a blade rubber is inserted into a groove portion of an antifreeze cover covering a wiper blade metal fitting, and the antifreeze cover is made of one kind selected from polybutadiene, polyisoprene and polyethylene butylene and polystyrene. An antifreeze wiper made of a block copolymer, wherein the outer surface of the base of the blade rubber is formed of the same material as that of the antifreeze cover, and the base is inserted into the groove of the antifreeze cover and heat-welded.