DD151132A5 - METHOD AND DEVICE FOR FORMING INNER LINE FOR THE PRODUCTION OF VEHICLE TIRES - Google Patents

Abstract

The invention relates to a method and an apparatus for the continuous production of inner tire wall parts for vehicle tires from different plastic masses in one operation. The simple and high-quality production of these parts and the tire should be made possible. According to the invention, the continuous production is carried out by extrusion, wherein the wall thickness of at least one of the tube layers is formed with intermittent enlargements or disassembling and a separation into tube sections takes place.

Description

Berlin, Aug. 27, 1980 _ AP B 29 H / 221 397

2 2 1 3 9 7 -Ι "57 600 26

Method and apparatus for forming inner liners for the production of vehicle tires

Field of application of the invention

The invention relates to a method and an apparatus for the continuous production of Reifenvandandvvandteilen from two different plastic masses in one operation.

Characteristic of the known technical solutions

A vehicle tire, in particular an automobile tire, before being put into the mold for vulcanization, is composed of many individual parts, the man carrying out this work being based on a special device for this construction, the so-called builder.

Although the main part of this builder, the drum around which the tire is built, can be moved by foot with a motor and also pressure rollers, for. B. pneumatically operated, take over many auxiliary work, the building of a tire today is still mainly manual work. The quality and pricing of a tire are largely determined by the builder, namely by two main factors:

a) The advantage in the production of the individual parts, ie • in the execution of these items for the work on the Builder and

b) the careful work of the man at the builder as well

the possibilities available to him.

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A particularly important one of said items used for building a tire is the so-called inner liner, d. H. the inner wall parts for the tire.

The innerliner forms the innermost part of the tire where the inner tube comes in contact with the tire. In today's most commonly used Tubless tires (tubeless tires), the innermost layer of butyl rubber, because of about eight times greater air impermeability to natural rubber and the second layer of a natural rubber mixture to ensure a good transition and best connection to the next structural layers.

Butyl rubber mixtures can be, however, very poorly connect with other elastomer blends, especially in the cold state, so that the innerliner profile in butyl quality before already brings together with the transitional rubber, vyenn always possible if both qualities are in a warm state.

This is still happening worldwide through a very labor-intensive and costly manufacturing process on plates and Doublierkalandern.

A today's Innerliner, z. B. for a small truck tire, is then constructed as shown in FIG. 1 of the drawing.

Since rubber compounds on the calender can only be made up to 1.5 or 1.8 mm thick to a certain extent free from bubbles, the upper layer is applied in a natural rubber

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shear mixture (or synthetic transition mixture) cut into two sheets 1.1 and 1.2 (Fig. 1) with a thickness of 1.5 mm calendered separately and on the Doublierkalander with the lower layer of butyl rubber, which also in two layers 1.2 and 1.4 (Fig ), each film being 1.8 mm thick, being laminated together.

Already in the production of the films themselves on the calender blistering during calendering can not be fully avoided at the material thicknesses to be selected. Bubble formation (air bubbles) occurs again and again during the doubling between the individual foils and at the overlaps of the finished profile plate. This has a negative effect on the quality of the finished R _e ifens.

However, arguably the most difficult problem in handling the innerliner at the -m tire building on the Builder is the splice, i. H. the composition point of the ends of the innerliner profile.

Of course, if the innerliner profile is composed of calendered films, it is an open streak which must be made endless on the builder's drum like a hose ring. Although the diagonally cut terminals of this flat innerliner profile are rendered sociable with either solvent or adhesive solution before they are laid on top of each other, and although the man at the builder devotes the greatest attention and time to this splice, air trapping, bad connection, and so on, occurs again and again Errors in this Zusarnmensetzstelle, what

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mostly leads to rupture of the splice and to committee.

The rupture is easily understood, considering that the innerliner is doubled before it is vulcanised with the remaining parts as a built-up tire. At the same time, the poor bondability of the buthyiene material with other elastomers must be taken into account, whereby the man at the builder does not always manage to precisely lay cut line on cut line of the same material of the end parts when splicing the inner liner profile on the builder drum.

Another negative point in calendering inner liner profiles is the fact that too much material is needed laterally, which could be saved. The optimum shaping would look like an inner liner profile band approximately according to FIG. 2, from which also, indicated by dashed lines, it can be seen which material is opposite The kalan ™ droned Innerliner could be saved.

Object of the invention

By the invention, the possibility should be created to produce tire inner wall parts cheap and high quality.

D arl ath the essence of the invent ung

The object of the invention is to provide a method and apparatus for the continuous production of inner tire wall parts from two different plastic masses in one

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Develop operation.

According to the invention this object is achieved by a method in which a tube of at least two layers of different plastic masses in one operation or directly following operations by Ex-

The wall thickness of at least one of the tube layers is formed with intervalwise thickenings or dilutions, and finally the thus formed tube sections are separated from the tube to form the individual tire wall parts.

It can be a hose made up of more than two layers of different plastic masses. In this case, various natural and / or synthetic rubber materials can be used to form the tube layers.

The changing in de wall thickness tube sections are preferably formed by controlled change of the material supply, which can be done by acting on the flow of material at the hose formation point or by a correspondingly pulsating material supply.

It is possible that the material supply takes place by direct change of the material delivery. It is also possible that the changed in wall thickness hose sections are made by controlled change of the hose withdrawal speed. Furthermore, the tube sections which change in wall thickness can be formed by

AP B 29 N / 221 397 57 600 26

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nenschicht applied to a correspondingly shaped mold tube and the outer layer or outer layers are sprayed on it.

The device according to the invention for carrying out the method consists of a spray head which can be connected to at least two extruders, at least two separate material feeds leading to the outlet of the extruder or to the hose formation point and by means for periodically controllably changing the material feed to the hose formation point.

It is advantageous that the means for controlling the supply of material to the hose forming point consist of elastic hollow rings, which are arranged in grooves in the outer pane and / or in the inner mandrel of the spray head, wherein means are provided, the hollow rings in a controlled manner by supplying gaseous or liquid Pulsating media more or less. It is advantageous that means for relative displacement of outer disk and / or inner mandrel to the central sleeve of the spray head are provided for the controlled change of the material supply. Furthermore, pulsed plasticizing and / or conveying devices for the material can be provided for the controlled change of the material supply.

With the object of the invention forming manufacturing. method, "optionally together with an inventive device, all previous problems and disadvantages are eliminated.

The basic idea in eliminating these problems

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lies in the fact that instead of an open profile band, which must be spliced together on the builder, a closed, ie endless band, in the form of a hose section is used, which the man at the builder can put on the builder's drum within seconds. postpone.

Working Example

The invention will be explained in more detail below by exemplary embodiments. In the accompanying drawing show:

3 shows purely schematically a piece of tubing produced according to the invention;

Fig. 4: a double-injection head according to the invention, for carrying out the method and

Fig. 5: purely schsmatisch a section of a spray head with means for generating the wave-shaped wall thickness of a hose.

However, since the innerliner in the middle must be relatively thick along the largest radius in the inner diameter of the tire (Figure 2) and laterally flattened towards the smallest inner diameter of the tire where the rim is seated, a tube must be extruded, with advantage in one operation, with two rubber qualities, which thickened and thinned in exactly controllable and adjustable intervals at axially always the same points, these thickenings and dilutions must be each radially gleichlaufend and centric.

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Such S _c hlauch 2, FIG. 3 of the drawing. The individual inner liners are formed by separating the tube sections 2 *, 2 ", 2"', etc. at the thinned points 3 ¹ , 3 ", 3"', etc., respectively.

When using such closed rings or hose sections which z. B. 500 mm inner diameter and 800 mm in length, the following main advantages arise:

- much less work in both the production of this innerliner as well as the builder, so when building the tire;

- less energy consumption;

- large material savings;

- no splicing work (assembly work) on the builder, which means: thus also. do not apply an adhesive solution on the slanted interfaces;

- The profile band length always remains the same, whereby a profile distortion can be avoided (eccentricity), and no tearing, since there is no assembly point; , , -

- completely air and dirt free connection between both elastomer layers;

- bubble-free profile band rings;

- better gas density (air impermeability);

- better quality of the final product;

- less committee.

Fig. 4 of the drawing shows a trained as a double spray head spray head 4, in which with two extruders

• simultaneously two different plastic masses can be extruded and formed into a tube with superimposed layers «

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In this case, the two extruders (not shown), at an angle of preferably 45 to the spray head axis set up, so that a good flow of material forward to the outlet 5 of the spray head 4 results. The materials flow over two elaborated center sleeves 6 and sleeve 7 with trained as Flußrichtungsinsn I _n nendorn 8 or outer disc 9 itself and meet - coming out - at the end of the middle sleeve 6 with high pressure and in the state of best plasticity to good connect to.

• Means are provided to the wall thickness of the tube to be formed in exactly determinable and controllable time resp. To change longitudinal sections and also to a precisely determinable extent, d. H. thinner and thicker to run approximately according to a desired wavy line (see Fig. 3). This change, d. H. Pulsing in the supply of material, is achieved by adding machined grooves 10; 11 on the part of the material flow on the outer disk 9 as well as on the inner mandrel 8 according to FIG. 5, hollow rings 12; 13 are inserted from elastic and heat-resistant material (Pulsierringe) which fed from the outside with gaseous or liquid media and thereby can be increased or reduced in a controlled manner, so that the material flow is reduced or enlarged accordingly (Fig. 5, 'dashed line 14 or 15 at the hollow rings 12 and 13 and the exiting tube when passing the nip, ie the narrowest point 16 between the hollow rings 12, 13, thinner becomes. The intervals for the pulsation are not described in detail, Controlled units known.

The pulsation can also be due to axial displacement

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be achieved by inner mandrel 8 and / or outer pane 9, wherein the material flow between the inner mandrel 8 and middle sleeve 6 on the one hand and outer pane 7 and middle sleeve on the other hand is changed.

The change of material flow, d. H. The pulsation, of course, can be achieved by displacement of the sleeve 6 in the axial direction.

The pulsing can also be achieved by changing the screw speed at the extruders (not shown) or by changing the take-off speed.

Another possibility is to achieve the pulsation by hydraulic cylinders, which carry out the transport of material through the spray head 4 instead of Schnekken in the extruder and / or in addition to the screws, as a pulsation element additionally press material directly into the spray head.

On the other hand, the change in the wall thickness of the tube can be achieved by injecting the inner tube onto a correspondingly shaped forming tube and spraying the outer tube over it.

The overmolding can be done in line with separate extruders or in a single pass with a double die head.

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8>

Claims (12)

AP B 29 H / 221 397 57 600 26 22 1397 Erfindunqsanspruch A method for forming inner liners for the production of vehicle tires of at least two different materials, characterized in that a hose (2) is made of at least two layers of different plastic masses in one operation or directly following operations by extrusion, wherein the Wall thickness of at least one of the tube layers is formed with intermittent thickening or dilution, and that finally the thus formed tube sections (2 *, 2 ", 2" ') are separated from the tube to form the individual tire wall parts. 2. The method according to item 1, characterized in that a tube is formed of more than two layers of different plastic masses. 3. The method according to item 1 or 2, characterized in that different natural and / or synthetic rubber materials are used to form the tube layers. 4. Method according to item 1, characterized by that the changing in the wall thickness hose sections are formed by controlled change of the material supply. 5. Method according to item 4, characterized by that the material supply by pulsating action - 12 - AP B 29 H / 220 57 600 26 22 13 97 -12- is controlled to the flow of material at the hose formation point. 6. The method according to item 4, characterized in that the material supply takes place by direct change of the material promotion. 7. The method according to item 1, characterized in that the changes in the wall thickness hose sections are made by controlled change of Schlauchabzugsgeschvvindigkeit. 8. The method according to item 1, characterized in that the changing in the wall thickness tube sections are formed by the inner layer applied to a correspondingly shaped mold tube and the outer layer or outer layers are sprayed on it. 9. Apparatus for carrying out the method according to item 1, characterized in that by at least two extruders connectable spray head (4), at least two separate to the outlet (5) of the extruder or the hose forming point leading material feeds and by means to the Material supply to the hose forming point to change periodically controllable. 10. The device according to item 9, characterized in that the means for controlling the supply of material to the hose forming point of elastic hollow rings (12; 13), which in grooves (10; 11) in - 13 - AP B 29 H / 220 57 600 26 2 2 1 3 9 7 '- is - the outer disk (9) and / or in the inner mandrel (8) of the spray head (4) are arranged, wherein means are provided, the hollow rings (12; 13) in a controlled manner by supplying gaseous or liquid media pulsating more or less expand. 11. The device according to item 9, characterized in that for the controlled change of the material supply means for relative displacement of the outer disc (9) and / or inner mandrel (8) to the central sleeve (6) of the spray head (4) are provided. 12. The device according to item 9, characterized in that provided for the controlled change of the material supply pulsating plasticizing and / or conveying devices for the material. For this 3 pages drawings