JPS6147685B2 - - Google Patents

Description

[Detailed Description of the Invention] This invention is applicable to, for example, a rolling flexible sleeve used as a part of a vehicle height adjustment air suspension or an air spring device, or 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.

2. Description of the Related Art Recently, a vehicle height adjusting 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, a cup-shaped outer shell 6 fixed to the upper end of the piston rod 5 of the shock absorber 2, and an outer shell. The flexible sleeve 8 is a flexible rolling member that is inverted midway to form a gas chamber 7 between the outer cylinder 6 and the outer cylinder 4.

By the way, if we look at the structure of the flexible sleeve 8 used in the air suspension 1, we will find that there are generally two layers of sudare weave cords, which are reinforcing layers within the rubber layer, running in opposite directions to prevent twisting when pressurized. It is made of a wrapped and embedded product, and when you look at its manufacture, it is made into a product 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, the unvulcanized rubber sheet for the inner layer is placed on a winding jig consisting of a roll, etc. (not shown), and the two layers of rubber are This is done by sequentially winding a toppings sare weave cord (wound in opposite directions) and an unvulcanized rubber sheet for the outer layer, but the above method requires a very large amount of labor to form the preform. In addition to this, there is also the disadvantage that the variation in preformed products becomes large.

Therefore, it is conceivable to form the cylindrical composite rubber preform using a general horizontal extruder, but when extruding rubbers 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 for extruding rubber had to be used, that is, an extruder with a core metal that matched the outer diameter of each rubber layer had to be used individually, so due to equipment layout. will need to take up a lot of space.

In this case, if you try to do it with one extruder,
Since the core metal etc. must be replaced, the work becomes a temporary stock. If stocked, there is an increased chance that foreign matter will adhere to the surface of the temporarily stored extrudate, and depending on the storage time, the extrudate may There is a risk that rubber compounding agents etc. may blow out on the surface of the product, affecting interlayer adhesion. Furthermore, when trying to extrude and coat the inner layer on a mandrel in the lateral direction, since the mandrel is short, if you simply try to feed it continuously, the end contact surfaces of the mandrels will move toward the extrusion head. At the time, it tends to shift in the vertical direction (perpendicular to the direction of movement of the mandrel), making it difficult to feed it into the extrusion head, and if it shifts after extrusion,
There is also a good chance that the extruded coating will be deformed.

In addition, in order to make the extruded inner layer into a single cylindrical shape,
If a cut is simply made in the circumferential direction at the end of the mandrel, the rubber will contract and turn up, and this turning up will make the next process difficult. In order to solve this problem, various studies have been made on the shape of the mandrel, and attempts have been made to suppress the shrinkage by, for example, adding grooves, protrusions, steps, knurling, etc. near the end of the mandrel, but none of them are suitable for practical use. Ta.

The object of the present invention is to solve the above-mentioned drawbacks of the prior art, to obtain a cylindrical preformed product using one extrusion head, and to produce a method for producing a cylindrical composite rubber preformed product that does not cause the end portion of the mandrel to turn over when cutting the rubber. The gist of this is to provide a mandrel from the upper entrance of the extrusion head, which has a through hole that is penetrated in the vertical direction and has an inner diameter larger than the outer diameter of the reinforcing layer that is coated before extruding the outer rubber layer. The inner layer is extruded onto the mandrel by allowing it to fall naturally in an upright position, and by pulling it down from the lower outlet of the extrusion head using a pair of belts with cushioning material located below the lower outlet. After the rear end of the mandrel has passed through the belt, the entire mandrel is stretched downward, twisted in the circumferential direction, and cut to cover the inner layer rubber up to the end face of the mandrel, and then the reinforcing layer is applied onto the inner layer. After coating the mandrel, the mandrel is again inserted into the extrusion head from above to coat the outer layer and passed through the belt, and then the entire mandrel is stretched downward again and twisted in the circumferential direction to cut the outer layer. The present invention provides a method for manufacturing a tubular composite rubber preform.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, as shown in FIG. A plurality of mandrels 10 with an outer diameter of about 42 mm and a length of 600 mm are prepared, and a reinforcing layer 21 with an inner diameter larger than the outer diameter ( A mandrel 14 having a through hole (11) is placed in the upper inlet 13 of an extrusion head 12 in an upright state and is continuously inserted by gravity, and from the extrusion head 12 an extruded coating for an inner layer made of an unvulcanized rubber material is inserted. Extrude and coat. When the mandrels 10 are inserted into the extrusion head 12, they are inserted in an upright state, and as shown in an enlarged view in FIG. Since the recess is formed so that the mandrels 10 can be inserted, there is no fear that the mandrels 10 will be misaligned. Moreover, the extrusion head 12 is mainly composed of a core bar 14 having a vertical through hole 11, a die 15, and a die holder 16, as shown in an enlarged view in FIG.

Next, as also shown in FIG.
4 and is clamped between a toothed belt 19 with a cushioning material 18 (urethane foam), which is a take-up device, and the mandrel take-up speed of the belt 19 is adjusted to a speed that is always higher than the extrusion speed of the inner layer 17, so-called The inner layer 17 is brought into close contact with the mandrel 10 by drawing down. By this withdrawal, as will be described later, as shown in FIG.
There is also an advantage that the thickness of the inner layer 17 can be adjusted as appropriate so that it can pass smoothly through the core metal 15 when the outer layer 22 is formed by being inserted into the core metal 15.

Next, after the mandrels 10 coated with the inner layer 17 are passed through the take-up belt 19, each mandrel 1
By further stretching the whole of the mandrel 10 downward and twisting it in the circumferential direction, the inner layer 17 completely covers the end face of the mandrel 10. For this reason, unlike in the past, when the rubber at the end of the mandrel is cut, there is no chance of it peeling off, and the user can start on the next task immediately.

Therefore, the work of winding the reinforcing sudare weave cords 20, 21, which are topped with rubber, in opposite directions on the inner layer 17 of the mandrel 10 from which the inner layer 17 has been twisted is as shown in FIG. It will start immediately. Furthermore, when the winding of the reinforcing layer 21 is completed, it is inserted into the extrusion head 12 again in the same way as the inner layer 17, but the outer diameter before the outer layer 22 is extruded and coated, that is, the outer reinforcing layer is Since the Sudare weave cord 21 layer is passed through the core bar 15 which has an inner diameter larger than the outer diameter, the Sudare weave cord 21
The unvulcanized outer layer 22 is smoothly extruded and coated on the layer, and after passing through the belt 19, the entire mandrel 10 is similarly stretched in the circumferential direction, twisted, and cut to form a cylindrical shape as shown in FIG. One step of the method for manufacturing composite rubber preform 23 is completed.

In this case, when the mandrel 10 coated with the inner layer 17 and the outer layer 22 is taken up by the take-up belt 19, the inner layer 17 and the outer layer 22 are separated from the urethane foam 1.
Since the belts 8 are in direct contact with each other, there will be no scratches on their outer surfaces, and since they are gently pressed down and pulled down, there is little concern that the extruded rubber will be deformed in thickness by the belt 19.

The unvulcanized cylindrical composite rubber preform 23 formed in such a preforming process is then set in a vulcanization mold and vulcanized in the same manner as in the past, and the surface after vulcanization is By performing finishing and other post-processes, the production of a flexible sleeve that can be used in the air suspension 1 shown in 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 carrying out a tube expansion operation at the final stage of the preforming process.

As described above, according to the present invention, the mandrel can be passed in the vertical direction (vertical direction) so that it can pass while standing.
The mandrel uses an extrusion head penetrated through the extrusion head and a take-up belt with a cushioning material, and the entire mandrel is twisted in the circumferential direction each time the inner layer and the outer layer are passed through the extrusion head and extruded and coated. First of all, there is very little misalignment between the mandrels, and there is no temporary stocking up during the work unlike in the past.Furthermore, there is no curling up when cutting the end rubber, so you can move on to the next work immediately. As a result of this, it is possible to obtain a large quantity of products with stable quality, and its industrial value is extremely large.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing a general air suspension for adjusting vehicle height, Fig. 2 is an explanatory diagram of the main part showing an embodiment of the present invention, Fig. 3 is an explanatory diagram of the main part of Fig. 2,
FIG. 4 is an explanatory diagram showing a main part of an 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: Concave groove, 10: Mandrel, 11: Through hole, 1
2: Extrusion head, 13: Upper inlet, 14: Core bar, 1
5: Dice, 16: Dice holder, 17: Inner layer, 18: Cushioning material, 19: Belt, 20, 21:
Sudare woven cord, 22: outer layer, 23: composite rubber preform.

Claims (1)

[Claims] 1. A mandrel is vertically penetrated and has a penetration larger than the outer diameter of the reinforcing layer to be coated before extruding the outer rubber layer. The inner layer is extruded onto the mandrel by pulling it down from the lower outlet with a pair of belts with cushioning material located below the lower outlet, and after the rear end of the mandrel passes through the belt, the inner layer is coated on the mandrel. Stretch it downward, then twist it in the circumferential direction,
After cutting, the inner layer rubber is coated up to the end face of the mandrel, and a reinforcing layer is further coated on the inner layer, and then the outer layer is coated by inserting it into the extrusion head from above again, and after passing through the belt. A method for producing a cylindrical composite rubber preform, comprising stretching the entire mandrel downward again, twisting it in the circumferential direction, and cutting the outer layer.