FI67808C - REGIONMERAT FORDONSDAECK - Google Patents

Description

! 67808

Retreaded vehicle tire. - Regummerat fordonsdäck.

The invention relates to a retreaded vehicle tire in which a bonding rubber layer is attached to the surface of a prefabricated tire carcass and a prefabricated rubber tread, gaseous inclusions are removed between superimposed layers and thus the preformed blank is autoclaved a roughening surface made simultaneously with the tread layer itself and considered to be bondable by the application of the bonding rubber mixture, consisting of protrusions and recesses forming a network of ducts.

In the manufacture of such tires, it is possible to achieve complete activation of the roughening surface made in the compression mold and to prevent oxidation and aging of the tread layer, so as to obtain an extremely strong bond between the tread layer and the tire carcass. However, the provision of this strong bond can be compromised when the rubber compounds of the tire carcass and the tread layer differ so much from each other that they are not compatible with each other. In addition, the top layers of steel, plastic, or fabric are damaged in some tire carcasses, causing the carcass to lose its original load-bearing capacity. They will then either have to be thrown away or the retreaded vehicle tire will be of poor quality.

Accordingly, it is an object of the invention to provide a retreaded vehicle tire in which a combination of otherwise incompatible rubber compounds for the tire carcass and tread as well as the use of damaged tire carcasses makes it possible to arrive at good quality tires.

To achieve this purpose, a vehicle tire according to the invention is characterized in that the rubber tread layer consists of a pre-vulcanized upper and lower part and that the side of the upper or lower part in each case has a roughening surface corresponding to the roughening surface of the lower part and thus the rubber tread layer.

By means of the stepped rubber compounds, hitherto incompatible tire carcasses and rubber tread layers can be attached to the lower and upper parts of the rubber tread layer. In addition, for the first time, a vulcanized rubber tread can be vulcanized to a cold-vulcanized tire carcass which does not have a bonding layer or whose bonding layer is damaged, the bonding layer or fabric being in the lower part according to the invention.

It is not necessarily necessary to vulcanize the rubber tread layer together in advance, but the same good ring properties are achieved if the vulcanization of the upper part to the lower part takes place together with the vulcanization of the lower part to the ring body.

The roughening surface made in the compression mold forms an effective network of ducts for draining gas inclusions due to the determinability of the distances between their protrusions and recesses, as well as the possibility to select the heights of the protrusions and recesses. The bonding rubber can then flow well in the recesses of the roughening surface. In this case, a relatively deep transition layer is formed from the top to the bottom of the rubber tread layer, in which case the transition layer must be considered to be that which results from the overlap of the vulcanized tread layer material and the bonding rubber.

In order to achieve activation of the roughening surface of the tread portions, it is essential to apply to these surfaces a solution of the bonding compound which does not vulcanize under normal storage conditions, i.e. a solution of natural or synthetic rubber dissolved in petrol, benzene or trichloroethylene. These solutions may also contain adjuvants, such as resin adhesion enhancing resins or antioxidants.

3 67808

The activation of the bonding surfaces by the bonding rubber compound immediately after the roughening of the facing sides of both tread layers is then caused by the mixture or unvulcanized rubber molecules therein binding to the still more reactive rubber or sulfur molecules of the bonding surface roughening reactivity. In this case, a physico-chemical connection can be observed, namely the exchange of ions between the H-bridges of the suitydihydryl groups.

The invention provides a retreaded vehicle tire, the lower and upper parts of the tread layer of which can be extremely thin, since no further mechanical roughening is required, but the roughening already takes place when the lower and upper parts are vulcanized in a compression die. The thin parts of the rubber tread layer have a beneficial effect on achieving good quality, since in this way there are less difficulties in centering the individual parts on the tire body.

Normally, the tread layers can be stretched and then pulled over the tire carcass. In the case according to the invention, at least the bonding layers of steel, plastic or fabric are embedded in the lower part of the rubber tread layer, stretching of these parts can no longer be performed, which must be reduced by inward pressing during coating.

The retreaded vehicle tire 1 according to the invention is illustrated in more detail below with reference to the exemplary embodiments shown in the accompanying drawings. In the drawings:

Fig. 1 is a perspective view of a tread tire having a roughening surface made in a compression mold on a side to be attached to the tire body.

Figure 3 shows a cross-section of a tread layer having 4 67808 a roughening surface formed in a compression mold.

Figures 4-7 show several cuts of roughening surfaces made in a compression mold with different roughening patterns.

Figure 8 shows a cross-section of a tire blank coated with a rubber tread layer consisting of a lower and an upper part.

Fig. 9 shows a ring or tire blank with coating layers, in which the outwardly extending edges of the tread in the left-hand half of the figure are subjected to tension, and in which the right-hand half shows a ring coated with a cover.

Fig. 10 schematically shows the lower part of the tread layer in which reinforcing bonds are embedded when the tire body is pulled on.

The inner side of the annular tread layer 1 shown in Fig. 1 has a roughening surface 3 and its outer surface has a profiling 2, both of which are formed simultaneously when manufacturing the tread layer 1 in a compression mold. Depending on the quality and shape of the matrix used, it is possible to select a structure for the roughening surface 3 with respect to both the determinable size and the distance of the protrusions 14 and the recesses 15 between them. Even the back-cut protrusions 15 can be made as shown in Fig. 6. Fig. 7 illustrates an example of the structure of the roughening surface 3, which can be made only by machining irregular recesses in the upper half of the mold or the lid of the mold.

It is clear that such a roughening surface 3 forms an excellent network of ducts for conducting gaseous and liquid substances away from the layer structure of the coated ring.

Fig. 8 shows the layer structure of a coated rubber tire, the ring body or carcass 8 of which is coated with a tread, i.e. a tread layer 1, formed by an upper part 1a and a lower part Ib provided with a support bandage 11. The lower part Ib reinforces the carcass 8, the circumference of which could be damaged and completely or partially rubbed off during the pre-production for the recoating of the carcass 8. Both sides of the lower part Ib are suitably roughened surfaces made in a compression mold. Since the lower part Ib is connected via the binder rubber layer 10 to the upper surface of the carcass 8, while the second binder rubber layer 9 arranged on the lower part Ib, which is also suitably passed over the lower part Ib, binds the upper part 1a to the lower part Ib and also the tread edges. The material coating indicated by reference numeral 12 must close the lateral outlets 12a of the layer structure before any of the above-mentioned pressures are applied to act on the layer structure of the coated tire to remove any gaseous and / or liquid inclusions.

In the left part of Fig. 9 it is shown that by placing the bonding rubber strip 12 under the tread edges 13 of the tread layer, i.e. the tread ring 1, in order to attach the layer structure to the carcass 8, a prestress can be provided therein.

The right-hand part of Fig. 9, on the other hand, illustrates how, especially in the case of bellows-shaped profiles, when the inner rubber not shown here is thin, suitably liquid and / or gaseous inclusions are led under the pulled-on cover 13, which is vacuumed after the tread 1 or its upper part 1a, is set on only loosely, scrolling continuously from the center to the sides. Suitably, the cover 13 is sealed to the groove 16 by means of a wheel rim and the closures guided to the sides are pulled out through a channel 15 made in front of the ring 14. Before placing the blank in the autoclave, this cover is removed.

Fig. 10 only schematically illustrates that the circumference of the sheath 6 67808 and thus the diameter of the carcass 8 must be reduced when the non-stretchable lower part Ib of the tread ring 1 is placed on the carcass 8. The reduction of the carcass 8 can be carried out, for example, by means of the rods 18 shown, which are suitably symmetrically fitted in a mechanical manner against the circumference of the carcass 8 and thus make it possible to pull on the lower part Ib.

Claims (3)

67808 A retreaded vehicle tire having a bonding rubber layer (10) attached to the surface of the prefabricated tire carcass (8) and a prefabricated rubber tread (1a, Ib) thereon, gaseous inclusions are removed between the superimposed layers and thus the prefabricated blank is heated in an autoclave , wherein the underside of the tread layer away from the tread has a roughening surface made in the compression mold simultaneously with the tread layer itself and considered to be bondable by the application of the bonding rubber mixture, consisting of bumps and that the side of the upper or lower part in each case towards the second part has a roughening surface which corresponds to the roughening surface of the lower side facing the ring body (8) of the lower part (Ib) and thus of the rubber tread layer. Retreaded vehicle tire according to Claim 1, characterized in that the upper (1a) and lower part (Ib) are vulcanized together by means of a bonding rubber layer in the same way as the lower part is vulcanized to the tire carcass (8). Retreaded vehicle tire according to Claim 1 or 2, characterized in that a support band (11) of steel, plastic or textile is arranged inside the lower part (Ib).