Zero-base contact surface, tire with zero-base contact surface, and tire retreading method

Abstract

The present invention relates to a contact surface (20) without a rubber subtread, comprising a plurality of notches (21) with a plurality of side walls (25), a plurality of grooves (30) with a TWI indicator (40) at the bottom, an outer surface (22), and an inner surface (27) between the notches (21), the contact surface (20) further comprising TWI indicators (40) that serve as connecting elements between the notches (21), and a space (35) between the side walls (25) without a rubber subtread at the bottom (30) of the grooves. The present invention also relates to a tire and a tire retreading method.

Description

Technical Field

[0001] The present invention relates to a tread surface for a tire retreading process, which consists of a base or subtread with 0% rubber usage. Furthermore, a tire retreading method using a rubber zero - base tread surface is shown.

[0002] The field of application of the present invention is a tread surface used in the tire retreading process, particularly for commercial vehicle tires.

[0003] The present invention mainly targets the tread surfaces of tires for land vehicles such as trucks, buses, semi - trailers, and road equipment. However, those skilled in the art will understand that it is not limited to the embodiments described in this document.

[0004] The content of this document can be applied to various tires available on the market.

Background Art

[0005] Tire retreading is a widely used and popular technology. In this process, the tread surface of a used tire is completely cut off. After removing the old tread surface, an adhesive sheet (usually a connecting rubber layer, also called a pad) is pasted onto the carcass. Then, the tread surface is provided. An envelope is attached to the tire so that a radial pressure is applied to the set of the tread surface, pad, and carcass. This set is vulcanized so that the tread surface is properly adhered to the tire's tread surface.

[0006] The tread surface usually has a plurality of grooves of various types and forms on its sidewall or outer peripheral surface according to the tire classification. There are cuts in the tread surface between these grooves. During vulcanization, the mechanical pressure of the pressure envelope on the tread surface is applied more to the cuts than to the groove parts. Therefore, the adhesive tends to move to the parts with less pressure, and the curing of the pad is not carried out uniformly. Furthermore, if the attachment of the tread surface to the carcass is inappropriate, there is a risk of air blockage or bubbles.

[0007] If the mechanical pressure applied to the carcass is not appropriate, or if air bubbles form, the adhesion between the contact surface and the tire will be insufficient, reducing the tire's resistance to the stresses of driving. This becomes particularly noticeable with heating during use. This increases the risk of damage to the contact surface during use, which could lead to an accident.

[0008] Generally, the contact surface has a rubber sub-tread just below the deepest groove, which acts as a connecting element between the grooves. This rubber sub-tread increases the weight of the tire and hinders heat exchange during road driving.

[0009] To mitigate the above-mentioned problems, means are known to equalize the pressure applied to the contact surface. Patent Document 1, disclosed on June 16, 1998, shows a tire retreading method in which an adhesive material sheet is placed on the outer surface of a cut carcass, and a pre-cured contact surface with grooves on its outer surface is attached on top of it. The tire is installed in a sealed state inside a flexible envelope, heated and pressurized under controlled conditions, and further, the pressure inside the envelope (50) is set to 0.8 to 1.5 kg / cm² higher than the atmospheric pressure of the controlled environment. 2 By applying low pressure, the tire being regenerated is subjected to controlled pressurized conditions. Such pressure within the envelope tends to improve adhesion of the contact surface to the carcass. However, even in this case, the mechanical pressure on the connecting material below the grooves tends to be higher than that on the portion below the grooves.

[0010] To avoid the aforementioned problems, it is desirable that the entire contact surface in contact with the carcass receives uniform mechanical pressure. A contact surface without a sub-tread, i.e., without a layer of rubber underneath, allows for the application of such uniform mechanical pressure. For example, Patent Document 2, disclosed on June 30, 1981, shows a sub-tread-less contact surface for use in off-road type tires. In this prior art, the pattern of the contact surface must always match the pattern of the tire's cuts. In this prior art, it is found that the cutting in the tire retreading process is partial or superficial. This type of tire is not intended for road use where heat resistance of the contact surface is essential.

[0011] Patent Document 3, disclosed on January 28, 2014, shows a tire without a rubber base on the contact surface. However, in this patent, the tread wear indicator (TWI) on the contact surface must be maintained below the groove, requiring partial cutting of the tread during the retreading process. Furthermore, the contact surface to which the tire is mounted must necessarily have the same pattern as the grooves on the remaining contact surface.

[0012] Therefore, conventional technology has not been able to demonstrate a contact surface with a rubber-free base, i.e., a contact surface without a sub-tread—where the tread is directly mounted to a completely machined carcass, resulting in reduced wear and extended tire life due to improved heat transfer from the tire to the outside, cost reduction due to reduced materials used, reduced wear on automotive mechanical parts and improved fuel efficiency due to reduced tire inertia resulting from reduced overall tire weight.

[0013] Conventional technology also fails to show a zero-base contact patch where the connecting elements between tread cuts act as a tread wear indicator (TWI). [Prior art documents] [Patent Documents]

[0014] [Patent Document 1] Brazilian Patent Application No. 9604105-6 [Patent Document 2] U.S. Patent No. 4276103 [Patent Document 3] U.S. Patent No. 8636044 [Overview of the project]

[0015] To reduce or eliminate the aforementioned disadvantages, the present invention provides a contact surface having a rubber-free base that is directly mounted to a carcass with a completely cut tread, and in which connecting elements between the cuts act as indicators.

[0016] Furthermore, the contact surface of this invention eliminates the rubber sub-tread and improves the heat transfer rate between the tire and the outside, thereby reducing wear and extending the tire's lifespan.

[0017] The solution proposed by this invention reduces the amount of material used in recycling, which in turn leads to cost reduction.

[0018] Because the sub-tread is eliminated, this invention reduces the total weight of the tire, thereby reducing the tire's inertia, resulting in fuel savings and reduced stress on mechanical parts such as automobiles.

[0019] An advantage of the present invention is that the pattern of the cuts in the zero-base tread does not depend on the pattern of the cut-out old tread, so it can be mounted on any cut-out tire carcass.

[0020] A further advantage is that by removing the rubber subtread, the mechanical pressure applied radially by the envelope is distributed uniformly across the pad, ensuring consistent adhesion within the contact surface and preventing air bubbles from forming between the tread and the carcass.

[0021] The solution presented in this invention provides safer, more durable, and more cost-effective retreaded tires for commercial vehicles, particularly trucks, buses, semi-trailers, road equipment, and the like.

[0022] The main object of the present invention is to provide a contact surface having a rubber-free base, i.e., a contact surface without a sub-tread, which is directly mounted to a carcass from which the tread has been completely cut, and in which connecting elements between the cuts act as indicators.

[0023] Similarly, an object of the present invention is to provide a contact surface that has a higher heat transfer coefficient between the tire and the outside, uses less material for recycling, and reduces the total weight of the tire.

[0024] Another object of the present invention is to realize a zero-base ground surface that can be used for any fully cut carcass, and to eliminate the occlusion of air between the two by making the radial mechanical pressure of the envelope against the tread uniform.

[0025] Finally, one of the objects of the present invention is a tire and a tire retreading method for the zero-base ground surface disclosed herein, and since there is no subtread, the entire ground surface receives the load from the envelope equally, so the mechanical pressure added by the envelope is uniform on the inner circumferential surface or the lower surface of the tread. Further, the possibility of generating air bubbles between the ground surface and the carcass is reduced.

[0026] In order to better understand the proposed method, a detailed description of the present invention will be given below.

Brief Description of Drawings

[0027] [Figure 1] Cross-sectional view of a ground surface of the prior art. [Figure 2] Cross-sectional view of the zero-base ground surface of one embodiment of the present invention. [Figure 3] Top view of the zero-base ground surface of one embodiment of the present invention. [Figure 4] Bottom view of the zero-base ground surface of one embodiment of the present invention.

Modes for Carrying Out the Invention

[0028] FIG. 1 shows a cross-sectional view of a ground surface ( ) of the prior art. As is well known, the ground surface ( ) includes a plurality of cuts, and an outer circumferential surface ( ) and grooves ( ) between these cuts ( ). At the lower part of the grooves ( ), a tread wear indicator TWI ( ) - Tread Wear Indicator of the ground surface is provided. The ground surface ( ) further includes a rubber subtread ( ).

[0029] In a well-known contact surface (10), the sub-tread (15) is a connecting element between the notches (11). The inner or lower surface of the sub-tread is supported by a pad (50), generally made of connecting rubber, which serves as an adhesive element between the tire's contact surface (10) and the carcass (not shown). As described above, this configuration has various disadvantages.

[0030] Figure 2 shows a cross-section of a zero-base or sub-tread-less contact surface (20) of a preferred embodiment of the present invention. The contact surface (20) consists of a plurality of notches (21) having an outer circumferential surface (22) and side walls (25), with grooves (30) provided between these notches (21). The lower part of the grooves (30) is provided with a contact surface wear indicator TWI (40).

[0031] The TWI indicator (40) functions not only as a wear indicator but also as a connecting element between the notches (21). Since there is no connecting subtread between the notches (21), when placed on the pad (50) during the tire retreading process, it allows for manipulation of the contact surface (20).

[0032] The inner circumferential surface (27) or lower surface of the contact surface (20) is supported by a pad (50), generally made of connecting rubber, which serves as an adhesive element between the tire's contact surface (20) and the carcass (not shown).

[0033] Figures 3 and 4 are a top view and a bottom view, respectively, of a contact surface (20) having a rubber zero base according to a preferred embodiment of the present invention. The side walls (25) of the notches (21) are provided with a space (35) below the groove (30) where there is no subtread, and the only connecting element between these notches (21) is a TWI indicator (40).

[0034] The notch (21) may further have grooves (26) on its outer circumferential surface (22) whose depth is less than the distance between the outer circumferential surface (22) and the inner circumferential surface (27). The shape of the grooves (26) will vary depending on the type of tire and the dynamics of driving based on the application.

[0035] Since the contact surface (20) does not require a sub-tread, the radial mechanical pressure applied by the envelope (during the remanufacturing process) is uniform between the inner circumferential surface (27) or lower surface of the tread and the pad (50) because the entire contact surface receives the load of the envelope (not shown) equally. Naturally, there is no mechanical pressure from the envelope on the surface of the pad (50) below the space (35). Therefore, since the space (35) allows for air circulation, the possibility of air bubbles forming between the contact surface (20) and the carcass is reduced.

[0036] The tire disclosed in this invention consists of the above-described rubber-free contact surface (20).

[0037] The tire retouching method of the present invention, which consists of a contact surface (20), is as follows: -The used contact surface was completely scraped down to the carcass (hidden), - Place the pad (50) on the tire carcass. -Attach the contact surface (20) onto the pad (50), - Apply the wrap so that radial air pressure is applied to the set of contact surface (20), pad (50), and carcass. - The set of the contact surface (20), pad (50), and carcass is vulcanized so that the contact surface (20) adheres to the tire carcass. It consists of the following steps: - The contact surface (20) does not require a rubber subtread.

Claims

1. A rubber subtread that does not have a rubber subtread contact surface (20), - Multiple notches (21) with side walls (25), - A plurality of grooves (30) are provided between the cuts (21), - A tread wear indicator (40) is provided at the bottom of the groove (30), -Outer surface (22) and inner surface (27), It consists of, The contact surface (20) is further - The tread wear indicator (40) acts as a connecting element between the notches (21). - Between the side walls (25), there is a space where the lower part (30) of the groove does not have a rubber subtread. It is characterized by the following.

2. The contact surface (20) of claim 1 is characterized in that the contact surface (20) is attached on a pad (50) which is attached on the tire carcass.

3. The contact surface (20) of the 1 is characterized in that the notch (21) has a groove (26) on its outer surface (22) that is shallower than the distance between the outer surface (22) and the inner surface (27).

4. - Tire carcass, -Having a contact surface (20) with multiple side walls (25) and notches (21), - The contact surface (20) has multiple grooves (30) between the cuts (21), - A tread wear indicator (40) is provided at the bottom of the groove (30), - The contact surface (20) has outer surfaces (22) and (27), Furthermore, regarding tires, - The tread wear indicator (40) acts as a connecting element between the cuts (21). - Between the side walls (25), a space (35) is provided below the groove (30) where a rubber subtread is not provided. A tire with a contact surface (20) but without a rubber subtread contact surface (20), characterized by the features of claims 1 to 3.

5. The tire according to claim 4, characterized in that the contact surface (20) is mounted on a pad and the pad (50) is mounted on a tire carcass.

6. The tire of claim 4, characterized in that the notch (21) has a groove (26) on its outer surface (22) that is shallower than the distance between the outer surface (22) and the inner surface (27).

7. - Completely scrape away the worn contact surface down to the carcass, - Place the pad (50) on the tire carcass. -Attach the contact surface (20) onto the pad (50), - Apply the wrap so that radial air pressure is applied to the set of contact surface (20), pad (50), and carcass. - The set of the contact surface (20), pad (50), and carcass is vulcanized so that the contact surface (20) adheres to the tire carcass. It is characterized by being carried out through the following steps, - A method for retreading a tire having a contact surface (20) according to claims 1 to 3, wherein the contact surface (20) does not require a rubber subtread.

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