WO2022137250A1

WO2022137250A1 - Cleaning an inner liner of a tire

Info

Publication number: WO2022137250A1
Application number: PCT/IN2021/050825
Authority: WO
Inventors: Divyansh Shukla; Binu Pallikkara Kesavan; Benny Joseph
Original assignee: Ceat Limited
Priority date: 2020-12-23
Filing date: 2021-08-27
Publication date: 2022-06-30

Abstract

Techniques of cleaning an inner liner of a tire 102 are described herein. A device 100 for cleaning the inner liner of the tire 102 comprises a laser power source 104 and a controller 106. The controller 106 is to control the laser power source 104 to remove a silicon layer from predefined locations at the inner liner of the tire 102 and to make ridges at the inner liner of the tire 102. The ridges are groove-like indentations on the inner liner of the tire 102. Further, the laser power source 104 is a CO2 laser power source. The ridges on the inner liner of the tire 102 allows a sealant to be adhered to the inner liner of the tire 102.

Description

CLEANING AN INNER LINER OF A TIRE

TECHNICAL FIELD

[0001] The present subject matter relates, in general, to a puncture safe tire and, particularly but not exclusively, to a technique of improving adhesion of a sealant to an inner surface of a puncture safe tire.

BACKGROUND

[0002] A tire incorporated in a vehicle may be punctured by any penetrating object in an area where immediate repair is difficult. Such situations encouraged the development of a puncture safe tire.

[0003] In a puncture safe tire, a compounded rubber or a sealant is filled inside the tire in a tread area of the tire. In the event of a puncture by a penetrating object, the sealant filled inside the tire fills a gap created by the penetrating object and prevents leak of air obviating the need of immediate repair. The sealant filled inside the tire needs to be strongly adhered to an inside surface of the tire in the tread area. Otherwise, application of the sealant may lead to unbalancing of the tire movement resulting in inefficient performance of the vehicle. To provide a strong adherence of the sealant to the inner surface of the tire, the inner surface of the tire is cleaned.

BRIEF DESCRIPTION OF DRAWINGS

[0004] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to reference like features and components.

[0005] Figure 1 illustrates a schematic of a device for cleaning an inner liner of a tire, in accordance with an example implementation of the present subject matter.

[0006] Figure 2 illustrates a perspective view of the device for cleaning the inner liner of the tire, in accordance with another example implementation of the present subject matter [0007] Figure 3 illustrates a method for cleaning an inner liner of a tire, in accordance with an implementation of the present subject matter.

DETAILED DESCRIPTION

[0008] The present subject matter relates to an automated and efficient technique of cleaning an inner liner of a puncture safe tire during manufacturing of the tire to improve adhesion of a sealant to the inner liner of the tire in order to provide an improved puncture safe tire.

[0009] As described above, in a puncture safe tire, a sealant is applied in an inner liner of the tire in a tread area. The sealant extrudes out and seals an area of the tire in case the area gets damaged by a sharp object. The sealant filled inside the tire needs to be strongly adhered to the inner liner of the tire in order to avoid the possibility of the sealant layer detaching from the inner liner of the tire. Detaching of the sealant layer may lead to imbalance of the tire during tire movement, resulting in inefficient performance of the vehicle.

[0010] During manufacturing of the tire, a silicon layer coating is done to the surface of the tire before a process of vulcanization. Due to the presence of silicon coating inside the tire, it is difficult to achieve adequate adhesion of the sealant to the inside of the tire. Therefore, before applying sealant in the inner liner of the tire corresponding to a tread area, the inner surface of the tire needs to be cleaned by removing the silicon coating.

[0011] There exist various techniques, to remove silicon coating from an inside surface of the tire in order to obtain a clean surface for enhancing adhesion between the sealant and the inner surface of the tire. These techniques include, but are not limited to, cleaning by solvent or other chemicals, or cleaning by mechanical processes, such as buffing.

[0012] Removing the silicon layer from the inner liner of the tire by use of chemicals is time consuming and involves manual intervention. The chemicals used in such cleaning processes are also costly. Further, cleaning with chemicals may not only impact health of an individual involved in performing the process but also the environment. In some cases, cleaning with chemicals may also have adverse effect on the surface of the tire. For instance, if the chemical is too abrasive or if it is handled improperly, for instance, if the inner liner of the tire is exposed to the chemical for imprecise timing, the inner liner may end up excessively corroded.

[0013] Cleaning through mechanical processes may also impact the surface of the tire through abrasive media used for cleaning in such cleaning process. Further, these techniques are time consuming as well as labor-intensive.

[0014] Accordingly, the conventional techniques also do not offer effective cleaning of the tire surface which may lead to poor adhesion of the sealant to the inner surface of the tire, when applied.

[0015] Further, cleaning through laser is also known in the art. Generally, fiber laser is used for cleaning the surface of the tire. However, fiber laser is not effective on non-metal parts, such as rubber, plastic or acrylic. Also, fiber laser systems are costly. Furthermore, even if a thoroughly clean surface is obtained after the cleaning process, adhesion of the sealant to the inner surface is difficult on a smooth surface. Thus, the cleaning achieved by the conventional laser-based techniques, fail to achieve the desired level of adhesion of the sealant to the inner liner of the tire.

[0016] In light of the foregoing discussions, there exists a need to overcome various problems associated with the conventional techniques of cleaning of an inner surface of a puncture safe tire before application of a sealant to the inner surface to promote strong and uniform adhesion of the sealant to the inner liner of the tire.

[0017] To this end, the present subject matter provides an automated, efficient and cost-effective technique for cleaning and processing of the inner surface of a puncture safe tire to enable strong and uniform adhesion of the sealant, upon applying the sealant to the inner surface during manufacturing of the tire.

[0018] A device for cleaning an inner liner of a tire is described in the present subject matter. In an embodiment, the device overcomes the above-described problems associated with the conventional techniques available for cleaning the inner surface of the tire before application of a sealant during production of the puncture safe tire.

[0019] In accordance with an embodiment of the present subject matter, the device for cleaning an inner liner of a tire comprises a laser power source and a controller. The laser power source is a CO2 laser power source. The controller controls the laser power source to remove a silicon layer from predefined locations of the inner liner of the tire corresponding to a tread area of the tire. As mentioned previously, a silicon layer is generally coated onto a surface of the tire before a process of vulcanization during production of the tire. The silicon layer is removed from the inner liner of the tire under the effect of the laser beam interacting with the inner liner to provide a clean surface for application of a sealant at the inner liner of the tire.

[0020] The controller is configured to control the laser power source to make ridges at the inner liner of the tire. The ridges are groove-like indentations formed on the inner liner of the tire. Upon application of a sealant to the inner liner of the tire, the ridges facilitate adherence of the sealant to the inner liner of the tire. As will be understood, the ridges being groove-like indentations provide more surface area to the sealant for adherence. Also, in carving out such ridges on the surface of the inner liner, the ridges may be provided a predefined degree of surface roughness. The surface roughness, i.e., shape and dimensions of the ridges is maintained to be uniform throughout the inner liner of the tire including a shoulder area and center of the inner liner. A non-uniform surface roughness may result in dislocation of the sealant applied at the inner liner of the tire subsequently which may in turn result in poor performance of the tire when incorporated in a vehicle.

[0021] With the implementation of the present subject matter, CO2 based laser source is used to clean the inner liner of the tire immediately under the tread area of the tire. Since, CO2 based laser source is most effective on non-metal parts, it provides an effectively clean surface in a short period of time, without damaging the inner liner of the tire, for the adhesion of sealant to the inner liner of the tire. Further, ridges, i.e., groove-like indentations formed on the inner liner of the tire through the CO2 laser source offers a better surface for the adhesion of the sealant to the tire. Better application of the sealant inside the tire results in enhancement of quality of the puncture safe tire produced as well as ensures stability in performance by the tire.

[0022] The above and other features, aspects, and advantages of the subject matter will be better explained with regard to the following description and accompanying figures. It should be noted that the description and figures merely illustrate the principles of the present subject matter along with examples described herein and, should not be construed as a limitation to the present subject matter. It is thus understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and examples thereof, are intended to encompass equivalents thereof. Further, for the sake of simplicity, and without limitation, the same numbers are used throughout the drawings to reference like features and components.

[0023] Figure 1 illustrates a schematic of a device 100 for cleaning an inner liner of a tire 102, in accordance with an example implementation of the present subject matter. While Figure 2 illustrates a perspective view of the device 100 for cleaning the inner liner of the tire, in accordance with another example implementation of the present subject matter. For sake of ease of explanation, Figures 1 and 2 are explained together.

[0024] In an implementation of the present subject matter, the device 100 comprises a laser power source 104. The laser power source 104 is a CO2 laser power source. The device 100 also comprises a controller 106 to control the laser power source 104 to remove a silicon layer from predefined locations at the inner liner of the tire 102. As described previously, a silicon layer is coated on a surface of the tire 102 before a process of vulcanization during manufacturing of the tire 102. The silicon layer or other contaminants present at the inner liner of the tire 102 obstructs subsequent adhesion of a sealant to the inner liner of the tire 102. Generally, the sealant is a viscous compounded rubber (butyl rubber sealant, liquid sealant, Bitumin, Polyurethane etc.) applied in a sheet form in the tread area of the tire. However, the sealant does not result in a good adhesion with the inner liner of the tire 102 in presence of the silicone layer. The CO2 based laser power source 104 removes the silicon layer and other contaminants from the predefined locations at the inner liner of the tire 102 to allow the sealant to bind to the inner liner of the tire 102.

[0025] The predefined locations may be an area at the inner liner of the tire 102 corresponding to a tread area 108 of the tire 102. In an example, the predefined locations may be selected based on a type of the tire, for example, motor-cycle tire, scooter tire, car tire or truck tire. The predefined locations to be cleaned may be stored in a memory (not shown in Figure) coupled to the controller. The memory may include any computer-readable medium known in the art including, for example, volatile memory (e.g., RAM), and/or non-volatile memory (e.g., EPROM, flash memory, etc.). The memory 206 may also be an external memory unit, such as a flash drive, a compact disk drive, an external hard disk drive, or the like. The controller may obtain the predefined locations from the memory and may then control the laser power source to remove the silicon layer and other contaminants from these predefined locations.

[0026] The controller 106 is further configured to control the laser power source 104 to make ridges at the inner liner of the tire 102. The ridges are groove-like indentations on the inner liner of the tire 102. These indentations prepare inner liner of the tire 102 for a subsequent process of adhesive bonding of a sealant to the inner liner of the tire 102. Shape and dimensions of the ridges may also be stored in the memory and the controller obtain the shapes and dimensions of the ridges from the memory to make the ridges on the inner liner of the tire corresponding to a tread area of the tire.

[0027] In an example, the controller 106 may be implemented as microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. The controller 106 controls laser power source 104 to remove the silicon layer from the inner liner of the tire 102 and to make ridges at the inner liner of the tire 102. For example, the controller 106 may be programmed to control operating parameters of the laser power source 102 such as angle of incidence and intensity of a laser beam emitted from the laser power source 102. In an example, operating parameters of the laser power source 102 to remove silicon layer may be different from the parameters required to make ridges at the inner liner. A focused laser beam is applied at the predefined locations at the inner liner of the tire 102 to remove the silicon layer from the respective locations and to make ridges at these locations. As mentioned previously, the inner liner of the tire 102 corresponds to a region 108 immediately under the tread area of the tire 102. Thus, the laser power source removes silicon layer from the inner liner of the tire 102 corresponding to the tread area 108 of the tire 102.

[0028] In an example implementation, a sealant is applied at the inner liner of the tire 102 covering a tread area 108 of the tire after removing the silicon layer. In an example, the sealant may be a sticky compounded rubber and may be applied in a hot state or molten form to the inner liner through an automated process. The sealant applied below the tread area 108 of the tire 102 adheres to the inner liner of the tire 102. In the event of a puncture, for example, through a sharp object, during the movement of the tire 102 on a road surface, the sealant injects out through the gap created on the surface of the tire 102 by the sharp object to fill the gap.

[0029] In an example implementation, the device 100 rotates the tire 102 in order to remove the silicon layer from the inner liner of the tire 102 and to apply the sealant at the inner liner of the tire 102. As the laser beam is applied to the surface of the tire 102 to remove silicon layer and to make ridges, the tire 102 needs to be secured in place so that the tire 102 does not shake, tremble or move. In an example, the tire 102 may be mounted on a tire holder (shown in figure 2) that securely hold the tire 102 and may rotate the tire 102, such that the laser beam may remove the silicon layer completely from the inner liner and make ridges throughout the inner liner of the tire 102.

[0030] A laser head of the laser source is pointed at one place, i.e., laser is in static condition and the tire is rotated to get a thoroughly cleaned inner liner of the tire and to make a uniform pattern of ridges of specified dimensions and shape at the inner liner of the tire. In an example, number of rotations of the tire may be pre-defined for a particular type of tire after performing multiple trials on that type of tire to be cleaned. Number of rotations of the tire to be cleaned also depends on presence of silicon quantity inside the tire. Further, as the number of rotations of the tire increases, tire cleaning time also increases. Thus, after multiple trials, parameters of laser source such as intensity of laser beam and number of rotations of the tire may be set in such a way that time required to remove the silicon layer from and to make ridges inside the tire is optimum, increasing the efficiency of the whole process. .

[0031] As will be understood, a pair of lower sidewall portion extending from both sides of the tread area comprises a bead portion located at a distal end of a respective lower sidewall portion. This bead area of the tire makes the removal of silicon layer from and making of ridges at the inner liner of the tire corresponding to the tread area difficult owing to the constriction created by the bead portion. Accordingly, in an example, the device also comprises a tire spreader (shown in figure 2) that spreads bead area of the tire from inside so as to facilitate removal of the silicon layer from inside of the tread area and a complete coverage of the tread area of the tire in the process of making of ridges by the laser source. For example, the tire spreader may clutch the bead portions on either side so that the inside area of the tire corresponding to the tread area may be completely exposed to the laser source. The tire spreader may be mounted on a fixed structure of the device 100 positioned so as to interface with the tire 102 mounted on the tire holder. [0032] In an example implementation, the device may comprise at least two sets of tire holder and tire spreader (110, 112; 114, 116) mounted on a base plate 118. The base plate is rotatable with respect to a location of the laser power source such that one of the at least two sets of tire holder and tire spreader is positioned before the location of the laser power source 104 at a time. For instance, the device comprises two sets of tire holder and tire spreader, i.e., a first set comprising a first tire holder 110 and a first tire spreader 112 and a second set comprising a second tire holder 114 and a second tire spreader 116 mounted on the base plate 118 to simultaneously perform unloading of a cleaned tire and loading of a tire to be cleaned on one set of tire holder and tire spreader, while process of silicon removal and ridge making through laser power source is in progress on other set of tire holder and tire spreader. The first set and the second set of tire holder and tire spreader may be mounted on a base plate 118. After the cleaning of a tire has been performed on one set of tire holder and tire spreader, e.g., on the first set, laser head of the laser source moves back to an original position from the point it was positioned to remove the silicon or make ridges. Jaws and brushes of the tire spreader come out and the cleaned tire may then be unloaded from the tire holder and tire spreader. Further, brush may be cleaned to remove the left-out carbon or silicon particles simultaneously with moving laser head back to the original position. These particles may be extracted using high power dust collector. After that, a tire to be cleaned may be loaded to this first set of tire holder and tire spreader and bead area of the tire to be cleaned may be stretched using the spreading jaws of the tire spreader and brushes may also be placed in position. While this whole process is performed with the first set of tire holder and tire spreader after cleaning of a tire, process of removal of silicon and making ridges on a tire may be in progress and completed on the second set of tire holder and tire spreader. Thereafter, the first set of tire holder and tire spreader where the tire to be cleaned is mounted may be placed before the location where the laser power source is positioned to clean the tire. This can be performed by rotating the base plate 118 on which both the sets of tire holder and tire spreader are mounted. Thus, having two sets of tire holder and tire spreader saves the time involved unloading of a cleaned tire and loading of a tire to be cleaned on the tire holder and tire spreader, since these processes may be performed in parallel with process of cleaning performed on other set of tire holder and tire spreader.

[0033] In an example implementation, the ridges made at the inner liner of the tire 102 facilitates the adherence of the sealant at the inner liner of the tire 102. The laser beam emitted through the laser source 104 creates micropatterns or ridges which are groove-like indentations on the inner surface of the tire 102. These ridges increase surface adherence of the inner liner of the tire 102 before applying a sealant at the inner liner of the tire 102. When the sealant is applied on the inner liner of the tire 102, ridges provides a surface with increased roughness so as to allow the sealant to get strongly adhered to the inner liner of the tire 102.

[0034] Figure 3 illustrates a method 300 for cleaning an inner liner of a tire, according to an example of the present subject matter. The order in which the method is described is not intended to be construed as a limitation, and any number of the described method blocks may be combined in any order to implement the method 300, or an alternative method.

[0035] It may be understood that blocks of the method may be performed, for example, by the above-described device for cleaning an inner liner of a tire as illustrated in Figure 1.

[0036] Referring to Figure 3, the method 300 starts at block 302. At block 202, a laser power source, such as the laser power source 104 of the device 100 removes a silicon layer from predefined locations at the inner liner of the tire 102. As mentioned above, the silicon layer is generally coated at a surface of the tire 102 before process of vulcanization during manufacturing of the tire 102 and obstructs, in case of a puncture safe tire, the adherence of a sealant to the inner liner of the tire 102 during a subsequent process of application is the sealant to the inner liner of the tire 102. The method further proceeds to block 304. At block 304, the laser power source 104 further makes ridges at the inner liner of the tire 104. These ridges are groove-hke indentations on the inner liner of the tire 102. The laser power source 104 is a CO2 laser power source. Being most-effective laser power source for non-metallic material, CO2 laser power source 104 provides a thoroughly clean surface for the adhesion of a sealant to the inner liner of the tire 102.

[0037] At block 306, a sealant is applied to the inner liner of the tire 102 corresponding to a tread area 108 of the tire 102 after removing the silicon layer. The sealant may be a sticky compounded rubber. The sealant extrudes out from the inner surface of the tire 102 in the event of a puncture through a penetrating object and fills the gap created by the penetrating object. The sealant needs to be strongly adhered to the inner surface of the tire 102 to avoid any disbalance of the tire 102 during a movement of the tire 102 on a surface, when incorporated in a vehicle. The ridges made at the inner liner of the tire 102 facilitates the adherence of the sealant in the inner liner of the tire 102. Further, as the sealant is applied at the inner liner of the tire 102 corresponding to the tread area 108 of the tire 102, the silicon layer is removed from the inner liner of the tire 102 corresponding to the tread area 108 of the tire 102 to provide a surface with improved surface adhesion for the adhesion of the sealant.

[0038] Although implementations of techniques for cleaning an inner liner of a tire is described, it is to be understood that the present subject matter is not necessarily limited to the specific features of the device described herein. Rather, the specific features are disclosed as implementations of the techniques for cleaning the inner liner of the tire.

Claims

I/We Claim:

1. A device 100 for cleaning an inner liner of a tire 102, the device 100 comprising: a laser power source 104, a controller 106 to control laser power source 104 to: remove a silicon layer from predefined locations at the inner liner of the tire 102; and make ridges at the inner liner of the tire 102, the ridges being groove-like indentations on the inner liner of the tire 102, wherein the laser power source 104 is a CO2 laser power source.

2. The device 100 as claimed in claim 1, wherein a sealant is applied at the inner liner of the tire 102 corresponding to a tread area 108 of the tire 102 after removing the silicon layer, and wherein the ridges are to facilitate the adherence of the sealant in the inner liner of the tire 102.

3. The device 100 as claimed in claim 1 or 2, wherein the laser power source 104 is to remove varying thickness of silicon layer from the predefined locations of the inner liner of the tire 102.

4. The device 100 as claimed in claim 1, wherein the device 100 comprises a tire holder to hold and rotate the tire 102 in order to remove the silicon layer from the inner liner of the tire 102.

5. The device as claimed in claim 4, wherein the device 100 comprises a tire spreader 112, 116 positioned so as to interface with the tire 102 mounted on the tire holder 110, 114, to spread bead area of the tire 102.

6. The device as claimed in claim 5, wherein the device 100 comprises at least two sets of tire holder and tire spreader 110, 112; 114, 116 mounted on a base plate 118, the base plate 118 being rotatable with respect to a location of the laser power source 104, wherein one of the at least two sets of tire holder and tire spreader is positioned before the location of the laser power source 102 at a time.

7. A method 300 for cleaning an inner liner of a tire 102, the method 200 comprising: removing 302 a silicon layer from predefined locations at the inner liner of the tire 102 using a laser power source 104; making 304 ridges at the inner liner of the tire 102 using the laser power source 104, the ridges being groove-like indentations on the inner liner of the tire 102; wherein the laser power source 104 is a CO2 laser power source.

8. The method 300 as claimed in claim 7, wherein the method 200 comprises applying 206 a sealant at the inner liner of the tire 102 corresponding to a tread area 108 of the tire 102 after removing the silicon layer.

9. The method 300 as claimed in claim 8, wherein the ridges are to facilitate the adherence of the sealant in the inner liner of the tire 102.

10. The method 300 as claimed in claim 7, wherein the method 300 comprises rotating the tire 102 while removing the silicon layer from the inner liner of the tire 102 and while applying the sealant at the inner liner of the tire 102.