JPS6139170B2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention can be used, for example, as a rolling flexible sleeve used as part of a vehicle height adjustment air suspension or an air spring device, or as a rolling material with a reinforcing layer embedded inside. The present invention relates to a method for manufacturing a cylindrical composite rubber preform for obtaining a composite rubber sleeve product.

Recently, a vehicle height adjustment air suspension 1 as shown in FIG. 1 has been used to improve the ride comfort or adjust the vehicle height of an automobile. Looking specifically at the air suspension structure, the vehicle height is adjusted by a shock absorber 2 that dampens vibrations due to oil flow resistance and by supplying and discharging compressed air from the outside depending on the load etc. The air suspension section 3 is composed of an outer cylinder 4 of the shock absorber 2 and an air suspension section 3 that can
A cup-shaped outer shell 6 is fixed to the upper end of the piston rod 5, and a flexible rolling member, a so-called flexible sleeve 8, is inverted from the middle to isolate a gas chamber 7 between the outer shell 6 and the outer cylinder 4. It consists of

By the way, when we look at the structure of the so-called flexible sleeve 8 used in the air suspension 1, we find that two layers of sudare-woven cords, which are reinforcing layers, are generally placed in opposite directions within the rubber layer to prevent twisting when pressurized. Consists of a wrapped and embedded material. In this case, if we look at the manufacture of the so-called flexible sleeve 8 having such a configuration, it is manufactured by passing through each process of pre-processing, preforming, vulcanization, and post-processing. However, in the preforming step, that is, the molding of the cylindrical composite rubber preform before vulcanization, as shown in FIG. This is done by sequentially wrapping two layers of rubber toppings sare weave cords 11 and 12 (wound in opposite directions) and an unvulcanized rubber sheet 13 for the outer layer, but in the above method, the preformed product The disadvantage is that it takes a very large amount of labor to mold the preform, and the variation in the preformed product is large. Therefore, it is conceivable to form the cylindrical composite rubber preform using a general extruder, but when extruding rubber with different extrusion diameters in two or more layers, an extruder for extruding the inner layer rubber and an extruder for extruding the outer layer It was said that two extruders had to be used for rubber extrusion, that is, an extruder with a core metal that matched the outer diameter of each rubber layer had to be used individually. It becomes necessary to take up space. In this case, if one extruder is used, the work will be temporarily scraped because the core metal etc. must be replaced, but during the scraping, foreign particles may be found on the surface of the extrudate that was temporarily stored. There is an increased chance of sticking to the extrudate, and depending on the storage time, there is a risk that rubber compounding agents etc. may ooze out onto the surface of the extrudate, affecting adhesion.

The purpose of this invention is to solve the above-mentioned drawbacks of the prior art, and to provide a method for producing a low-cost cylindrical composite rubber preform with stable quality using a single extruder without using multiple extruders. The gist of this is to allow a mandrel to fall naturally in an upright position from the upper inlet of an extrusion head that penetrates in the vertical direction, and to insert the mandrel, and to pull it down from the lower outlet of the extrusion head. The method for manufacturing a cylindrical composite rubber preform includes extrusion coating an inner layer onto the mandrel, coating the inner layer with a reinforcing layer, and then inserting and passing through the extrusion head from above again.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 3, reference numeral 14 is a manufacturing device for a cylindrical composite rubber preform used in an embodiment of the present invention; An extruder 20 has an extrusion head 19 in which a through hole 18 is formed in the vertical direction so that a mandrel 16 inserted from an upper inlet 15 is taken out from a lower outlet 17, and the extrusion head 19 is arranged below the lower outlet 17. The extrusion head 19 mainly consists of a cylindrical core 22, a die 23, and a die holder 24, as shown in an enlarged view in FIG. In this case, as shown in FIG. 5, the inner diameter d ₀ of the core bar 22 is larger than the outer diameter d ₁ of the outer reinforcing layer 12 covered before the outer rubber layer 27 is extruded. The device 21 consists of a pair of toothed belts 21, and a cushioning material made of urethane foam 25 is pasted on the surface of the belt, as shown in an enlarged view in FIG. It consists of

To explain the method for manufacturing a cylindrical composite rubber preform using a manufacturing apparatus having such a configuration, first, as shown in FIG. 3, in order to form two preforms at once, an intermediate Mandrel 1 with an outer diameter of approximately 42 mm and a length of 600 mm with a ring-shaped groove on the outer periphery.
6 is prepared, and as shown in FIG. 3, it is inserted into the extrusion head 19 which penetrates in the vertical direction by vertically falling from the upper entrance 15 in an upright state, and from the extrusion head 19, the extruded coating material for the inner layer is The unvulcanized rubber material 26 is extruded. Since the outer diameter of the mandrel 16 is smaller than the inner diameter d ₀ of the core metal 22, the mandrel 16 naturally passes through the core metal 22, but the tip side of the mandrel 16 is made of extruded cylindrical unvulcanized rubber for the inner layer. The drop is suppressed by the , and the extruded inner layer 26 is coated while further falling at a constant speed. and a mandrel 16 coated with an inner layer 26
When the leading end side is clamped between the toothed belts 21 which are pulling devices, the speed at which the belt 21 pulls up the mandrel 16 is adjusted to be always higher than the extrusion speed of the inner layer 26 in order to bring the belt 21 into close contact with the inner layer 26 on the mandrel 16. Since the speed is such that the so-called inner layer 26 is drawn down, the inner layer 26 is formed on the mandrel 16 in close contact with the inner layer 26 by drawing down. When the outer layer 27 is formed by inserting it again as shown in FIG. There are some advantages to doing so.

Next, two layers of reinforcement cords 11, 12, as shown in FIG. 2, are wound in opposite directions around the mandrel 16, which has been passed through the take-up belt 21 and coated with the inner layer 26, as shown in FIG. After the layers are laminated as shown in FIG. 1, the mandrel 16 on which they are laminated is inserted into the extrusion head 19 again as described above. In order to pass through the core bar 22 which has an inner diameter larger than the outer diameter d ₁ of the Sudare weave cord 12, the outer periphery of the Sudare weave cord 12 is smoothly coated with an unvulcanized outer layer 27.
The manufacture of a cylindrical composite rubber preform 28 as shown in the figure is completed. In this case, a mandrel 16 coated with an inner layer 26 and an outer layer 27 by a take-up belt 21
Since the urethane foam 25 comes into direct contact with the inner layer 26 and the outer layer 27 when taking it off, there is no damage to their outer surfaces, and since the belt 21 pulls them off by pressing them gently, the thickness of the extruded rubber is deformed by the belt 21. There is very little worry that this will occur.

The unvulcanized cylindrical composite rubber preformed product 28 formed in such a preforming process is then set in a vulcanization mold as in the past and then vulcanized, and then further vulcanized after vulcanization. By performing surface finishing and other post-processes, the manufacture of the flexible sleeve 8 that can be used in the air suspension 1 of FIG. 1 is completed.

It goes without saying that if it is desired to manufacture a tapered flexible sleeve, it can be easily obtained by performing a tube expansion process at the last stage of the preforming process.

As described above, according to the present invention, the inner layer, the reinforcing layer Since it is possible to carry out so-called one-piece flushing work (or continuous work) in the order of the outer layer, there is no need to temporarily stock the work as in the past, and this eliminates the possibility of foreign matter adhering to the surface or rubber compound. I don't have to worry about getting a speech bubble. Moreover, the space required is small, and a large amount of molded products with stable quality can be obtained, which has great industrial value.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a general vehicle height adjustment air suspension, Fig. 2 is an explanatory diagram showing a part of the conventional preliminary process, and Fig. 3 is an explanatory diagram showing a part of the conventional preliminary process. FIG. 4 is an enlarged explanatory view of the main part of FIG. 3, and FIG. 5 is an explanatory view of the main part of the manufacturing apparatus used in one embodiment of the present invention. 1...Vehicle height adjustment air suspension, 2...
Shock absorber, 3...Air suspension section, 4...Outer cylinder, 5...Piston rod, 6
... Outer shell, 7 ... Gas chamber, 8 ... Flexible sleeve, 9 ... Roll, 10, 13 ...
Rubber sheet, 11, 12...Sudare weave cord,
14... Manufacturing equipment, 15... Upper inlet, 16... Mandrel, 17... Lower outlet, 18... Through hole, 1
9... Extrusion head, 20... Extruder, 21... Belt, 22... Core bar, 23... Die, 24...
Dice holder, 25... Cushioning material, 26... Inner layer rubber, 27... Outer layer rubber, 28... Cylindrical composite rubber preform.

Claims (1)

[Claims] 1. The inner layer is extruded and coated onto the mandrel by allowing the mandrel to fall naturally in an upright state from the upper entrance of the extrusion head penetrating in the vertical direction and pulling it down from the lower exit of the extrusion head, A method for manufacturing a cylindrical composite rubber preform, which further comprises coating the inner layer with a reinforcing layer and then inserting and passing through the extrusion head from above again to form an outer layer coating.