Patent Publication Number: US-2020298515-A1

Title: Rubber base attachment method and tire with sensor

Description:
TECHNICAL FIELD 
     The present invention relates to a tire with a sensor attached on an inner surface side of the tire, for acquiring information of the tire, and a method of attaching a rubber member, which is configured to mount thereon or house therein a sensor module, on an inner surface of the tire. 
     BACKGROUND 
     In general, there has been practiced that, when acquiring information of a tire such as a tire inner pressure, a tire temperature or a tire deformation amount, a sensor module is attached to a surface of an inner liner that is an inner surface side of the tire by an adhesive agent or the like. The sensor module includes sensors such as a pressure sensor, a temperature sensor or a piezoelectric element attached to a substrate having an amplifier, a transmitter and so on mounted thereon, and also includes a housing for protecting these elements. 
     Incidentally, in a method in which the above-mentioned sensor module is directly fixed to the inner liner, there has been a problem that when an input to the tire is large, deformation of rubber becomes large. As a result, the sensor module is peeled off from the inner liner when driving a long-distance. 
     Accordingly, in order to relax the stress acting between the sensor module and a rubber member of the inner liner, there has been proposed a tire information acquisition device  30  in which, as illustrated in  FIG. 7A , a rubber base  31  is adhered and fixed on the surface of an inner liner  11  that is an inner surface side of a tire  10  by using an adhesive agent for rubber such as a chloroprene-based adhesive agent, or a tire information acquisition device  40  in which, as illustrated in  FIG. 7B , a sensor module  42  is housed in a rubber base  41  having an opening part  41   p  which serves as an insert/remove port for inserting and removing a mounting part  42   n  connected to a holding part  42   m  of the sensor module  42 , and a housing recess part  41   q  which houses the mounting part  41   n  and which is surrounded by a bottom part  41   a  to be adhered to the surface of the inner liner  11  and a side wall part  41   b  that connects the bottom part  41   a  and the opening part  41   p  (for example, see Patent Documents 1 and 2). 
     CITATION LIST 
     Patent Document 
     
         
         Patent Document 1: Japanese Unexamined Patent Application Publication No. 2009-166745. 
         Patent Document 2: Japanese Unexamined Patent Application Publication No. 2015-160512 
       
    
     SUMMARY OF THE INVENTION 
     Technical Problem 
     However, because a mold release agent applied layer having a mold release agent, such as silicone to be used at the time of vulcanization, adhered thereon is formed on the surface of the rubber member which constitutes the inner liner  11 , there has been a problem that the rubber base  31  or the rubber base  41  is easily peeled off. 
     Therefore, normally, a method is performed in which the mold release agent applied layer is removed by cleaning the surface of the inner liner  11  with the use of an organic solvent. However, since not only cleaning by the organic solvent takes time, but also it is difficult to remove the mold release agent in the vicinity of a ridge, adhesiveness of the rubber base  31  or of the rubber base  41  has not been sufficient enough. 
     Further, it is also conceivable to use a method of removing the mold release agent applied layer by buffing or sandblast treatment, however, in this case as well, there is a problem that not only it takes time to sufficiently remove the mold release agent applied layer, but also the rubber member of the inner liner  11  is shaved off, resulting in greatly damaging the inner liner  11 . 
     The present invention has been made in view of the conventional problems and aims at providing a method of efficiently removing a mold release agent applied layer and securely adhering and fixing a rubber member on a surface of an inner liner. 
     Solution to Problem 
     The present invention relates to a method of attaching a rubber member on an inner surface of a tire, including: a step (a) of identifying an attachment position for attaching the rubber member; a step (b) of irradiating laser light to the attachment position to remove a mold release agent applied layer formed on a surface of a rubber layer, which is located at the attachment position and which configures an inner liner; a step (c) of irradiating laser light with less irradiation energy than that of the laser light irradiated in the step (b) to the position where the mold release agent applied layer has been removed, to remove the surface of the rubber layer located at the attachment position; and a step (d) of adhering the rubber member to the attachment position. 
     Furthermore, the present invention relates to a tire with a sensor, the tire having a sensor module housed in the rubber base attached by the above-mentioned attaching method, or having a sensor module mounted on the rubber base attached by the above-mentioned attaching method. 
     The summary of the invention does not enumerate all the features required for the present invention, and sub-combinations of these features may also become the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flowchart illustrating a method of attaching a rubber base according to an embodiment of the present invention; 
         FIGS. 2A and 2B  are views each illustrating the method of attaching the rubber base according to the embodiment of the present invention; 
         FIGS. 3A to 3E  are views each illustrating the method of attaching the rubber base according to the embodiment of the present invention; 
         FIG. 4  is a table illustrating a relationship between irradiation energy of laser light and a thickness of a removed rubber: 
         FIG. 5  is a table illustrating a relationship between the irradiation energy of laser light and silicone removability: 
         FIG. 6  is a graph illustrating check results of silicone removability and rubber adhesiveness after irradiating the laser light to a surface of an inner liner; and 
         FIGS. 7A and 7B  are views each illustrating an example of a tire information acquisition device. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Embodiments 
     Hereinafter, a method of attaching a rubber base according to an embodiment of the present invention will be described with reference to the flowchart in  FIG. 1 . 
     First of all, as illustrated in  FIGS. 2A and 2B , after identifying an attachment position A for attaching a rubber base  31  on an inner surface side of an inner liner  11  of a tire  10  (step S 11 ), a laser device  20  and a not-shown moving means for moving the laser device  20  are disposed on the inner surface side of the tire, that is, above the attachment position A (step S 12 ). 
     In the present embodiment, as the rubber base  31 , a rubber base  31  to be disposed between a sensor module  32  and the inner liner  11  was used, as illustrated in  FIG. 7A . 
     Next, as illustrated in  FIG. 3A , silicone removal processing is performed for removing, by laser processing, a silicone layer  12  that is a mold release agent applied layer formed on the inner surface side of the inner liner  11  (step S 13 ). 
     Meantime, the thickness of the rubber member constituting the inner liner  11  is about 1 mm and the thickness of the silicone layer  12  is about 10 to 100 μm. 
     Here, assuming that the maximum irradiation energy, which is irradiation energy of the laser light achieved when the laser device  20  is set to the maximum output, is P 0 . The maximum irradiation energy P 0  is, as illustrated in the graph of  FIG. 6 , the irradiation energy (about 10 W) capable of removing about 58 μm of the rubber of the inner liner by three times of irradiations. Incidentally, when the irradiation energy is set to P 1 =0.8×P 0 , about 37 μm of the rubber of the inner liner can be removed by three times of irradiations, and when the irradiation energy is set to P 2 =0.6×P 0 , about 30 μm of the rubber of the inner liner can be removed by three times of irradiations. Further, when the irradiation energy is set to P 1 =0.4×P 0 , about 22 μm of the rubber of the inner liner can be removed by three times of irradiations. 
     In the present embodiment, the irradiation energy in the silicone removal processing is set to P 1 =0.8×P 0 , and the laser device  20  is moved at a predetermined moving speed in the tire circumferential direction and in the tire width direction for scanning the laser light, to thereby uniformly irradiate the laser light to the attachment position A. 
     As illustrated in the table of  FIG. 4 , when the irradiation energy of the laser light is set to P 1 =0.8×P 0 , most of the silicone layer  12  can be removed by two times of irradiations. When the irradiation is performed three times, the silicone layer  12  can be removed completely. 
     Incidentally the “applied total energy” in the table of  FIG. 4  is (irradiation energy P)×(number of times of irradiations n), and is represented by indices where one (1) indicates a case in which the irradiation energy is P 1  and the number of times of irradiations is three times. 
     Whereas, in the case where the irradiation energy of laser light is set to P 2 =0.4×P 0 , even though the applied total energy exceeded one (1), the silicone layer  12  could not be removed. 
     It is conceivable that this result came out because when the irradiation energy of the laser light is P s  or more, where P 2 &lt;P s &lt;P 1 , C/B (carbon) contained in the rubber member of the inner liner  11  generates heat, and by this heat generation, the silicone is melted and evaporated. 
     Meanwhile, it is conceivable that when the irradiation energy of the laser light is less than P s , the C/B cannot generate heat, and even if the applied total energy exceeds one (1), the silicone is not melted and evaporated, hence as a result, the silicone layer  12  was not removed. 
     In the case where the irradiation energy of the laser light is not less than P s , as illustrated in  FIG. 3B , the silicon layer could be removed, however, not only a silicone bleed object  11   a  was remained on the surface, but also an altered layer  11   b  was formed on the surface of the rubber member of the inner liner  11 . Therefore, in the laser processing in the step S 13  only, the silicone layer  12  could be removed, but it was difficult to obtain an adhesive force equivalent to that of the rubber member on which the silicone layer  12  is not attached. 
     Thus, in the present embodiment, as illustrated in  FIGS. 3C and 3D , a silicone bleed object  11   a  remaining on the surface of the rubber member and an altered layer  11   b  on the surface of the rubber member of the inner liner  11  are removed by performing the laser processing again, so as to secure the adhesive force equivalent to that of the rubber member before the silicone layer  12  is adhered thereon. 
     That is, in the step S 14 , the output of the laser device  30  is set to P 2 =0.4×P 0 , and similarly to the step S 13 , the attachment position A wherefrom the silicon layer  12  has been removed is subjected to the rubber layer surface removal processing in which the laser light is irradiated three times uniformly. 
     Since the irradiation energy P 2  of the laser light is low energy (P 2 &lt;P s ), C/B does not generate heat, and the rubber member can be removed little by little. Therefore, as illustrated in the figures, the bleeding object and the altered layer on the surface of the rubber member can be reliably removed without damaging the rubber member of the inner liner  11 , so that the state of the surface of the rubber member of the inner liner  11  can be brought into substantially the same state as that of the rubber member before the silicone layer  12  is adhered. 
     Finally, as illustrated in the figure, after applying an adhesive agent to the attachment position A that has been subjected to the rubber layer surface removal processing (step S 15 ), as illustrated in  FIG. 3E , the rubber base  31  having the sensor module  32  mounted thereon is adhered to the surface of the inner liner  11  (step S 16 ). In  FIG. 3E , the reference numeral  14  denotes an adhesive layer. 
     Embodiments 
     The table of  FIG. 5  illustrates results of examination of the silicone removability and the rubber adhesiveness after irradiating the laser light on the surface of an inner liner having a silicone layer formed on the tire inner surface side. 
     The moving pitch of the laser light is 60 μm and the moving speed is 4,000 mm/s. 
     In Embodiment 1, the irradiation energy in the silicone removal processing was P 1 =0.8×P 0 , the number of times of irradiations was n 1 =3 times, the irradiation energy in the rubber layer surface removal processing was P 2 =0.6×P 0 , and the number of times of irradiations was n 2 =3 times. 
     Embodiment 2 is the same as that of the Embodiment 1 except that the number of times of irradiations in the rubber layer surface removal processing was n 2 =6 times. 
     Embodiment 3 is the same as that of the Embodiment 1 except that the irradiation energy in the rubber layer surface removal processing was P 2 =0.4×P 0  and the number of times of irradiations was n 2 =3 times. 
     Embodiment 4 is the same as that of the Embodiment 1 except that the irradiation energy in the rubber layer surface removal processing was P 2 =0.4×P 0  and the number of times of irradiations was n 2 =6 times. 
     Embodiment 5 is the same as that of the Embodiment 1 except that the irradiation energy in the rubber layer surface removal processing was P 2 =0.4×P 0  and the number of times of irradiations was n 2 =10 times. 
     In Comparative Example 1, the irradiation energy in the silicone removal processing was P 1 =0.4×P 0  and the number of times of irradiations was n 1 =6 times, and the rubber layer surface removal processing was not performed. 
     In Comparative Example 2, the irradiation energy in the silicone removal processing was P 1 =0.8×P 0  and the number of times of irradiations was n 1 =3 times, and the rubber layer surface removal processing was not performed. 
     In Comparative Example 3, both of the irradiation energy and the number of times of irradiations in the silicone removal processing, and the irradiation energy and the number of times of irradiations in the rubber layer surface removal processing were set to P 1 =0.8×P 0  and n 1 =3 times. 
     As illustrated in the table of  FIG. 5 , when the irradiation energy in the silicone removal processing is small, the silicone layer could not be removed. 
     Further, when high irradiation energy P 1  was irradiated in the silicone removal processing, the silicone layer could be removed, but the adhesiveness was not improved. 
     Furthermore, it was confirmed that when the rubber layer surface removal processing is not performed, the adhesiveness is not improved. 
     In addition, also in the case where the rubber layer surface removal processing was performed with high-energy laser light, the adhesiveness was not improved. 
     On the other hand, it was confirmed that, as in Embodiments 1 and 2, when the silicone removal processing was performed with high-energy laser light and the rubber layer surface removal processing was performed with low-energy laser light, not only the silicone can be sufficiently removed but also the adhesiveness after the processing is improved. 
     In addition, as in Embodiments 3 to 5, it was found that even when the irradiation energy P 2  in the rubber layer surface removal processing is set from 0.6×P 0  of Embodiments 1 and 2 to 0.4×P 0 , the state of the surface of the rubber member of the inner liner can be made to be an excellent state in terms of the adhesiveness as substantially the same with that of the rubber member before the silicone layer is attached. 
     As can be seen from comparison between Embodiments 1 and 2 and Embodiments 3 to 5, in the rubber layer surface removal processing, the adhesiveness is improved as the number of times of irradiations is increased. Therefore, it was found that the thickness of the rubber to be removed by the rubber layer surface removal processing is preferably about 60 μm, although it depends on the magnitude of the applied total energy in the silicone removal processing. 
     The present invention has been explained using the exemplary embodiments, however, the technical scope of the present invention is not limited to the scope described in the above exemplary embodiments. It is apparent to those skilled in the art that various changes and modifications may be added to the exemplary embodiments. It is also apparent from the scope of the claims that embodiments with such changes or modifications may also be included within the technical scope of the present invention. 
     For example, in the exemplary embodiments described above, the irradiation energy of the laser light and the number of times of irradiations in the silicone removal processing were set to P 1 =0.8×P 0  and n 1 =3 times, and the irradiation energy of the laser light and the number of times of irradiations in the rubber surface removal processing were set to P 2 =0.4×P 0  and n 2 =3 times. However, P 1 , P 2  and n 1 , n 2  are not limited to the above-mentioned values, and P 1  and n 1  may be values by which the silicone layer  12  can be removed, and P 2  may be set to be smaller than P 1 . It is desirable that P 2  and n 2  are such values by which the silicone layer  12  cannot be removed even if P 2 ×n 2 &gt;P 1 ×n 1 . 
     Further, P 0  may be appropriately determined according to a tire type or the like. 
     In the exemplary embodiments described above, after applying the adhesive agent to the attachment position A having been subjected to the rubber layer surface removal processing, the rubber base  21  was adhered to the surface of the inner liner  11 . Alternatively, the rubber base  21  may be adhered to the inner liner  11  by applying the adhesive agent to the bottom surface of the rubber base  21 . 
     Further, in the exemplary embodiments described above, as the rubber base, the rubber base  31  disposed between the sensor module  32  and the inner liner  11  was used, as illustrated in  FIG. 7A . However, the rubber base  41  that houses the sensor module  42  may be used, as illustrated in  FIG. 7B . 
     In summary, the present invention may be described as follows. Namely, according to an aspect of the present invention, there is provided a method of attaching a rubber member on an inner surface of a tire, including: a step (a) of identifying an attachment position for attaching the rubber member; a step (b) of irradiating laser light to the attachment position to remove a mold release agent applied layer formed on a surface of a rubber layer, which is located at the attachment position and which configures an inner liner; a step (c) of irradiating laser light with less irradiation energy than that of the laser light irradiated in the step (b) to the position where the mold release agent applied layer has been removed, to remove the surface of the rubber layer located at the attachment position; and a step (d) of adhering the rubber member to the attachment position. 
     Whereby, the release agent applied layer can be securely removed and the rubber layer on the surface of the inner liner whose adhesiveness has been deteriorated as having been damaged by the laser light irradiated in the step (b), can also be removed. Accordingly, the rubber member can be securely and firmly attached to the inner surface of the tire. 
     Further, when the irradiation energy of the laser light in the step (b) is P 1  and the number of times of irradiations in the step (b) is n times, and the irradiation energy of the laser light in the step (c) is P 2  and the number of times of irradiations in the step (c) is m times, the P 2  is such a magnitude that cannot remove the mold release agent applied layer even when P 2 ×m&gt;P 1 ×n, so as to be able to efficiently remove only part of the rubber layer, which is located on the damaged surface, of the rubber layer on the surface of the inner liner. 
     Whereby, a rubber base having housed therein a sensor module provided with a sensor for acquiring information of the tire or a rubber base disposed between the inner liner and the sensor module provided with the sensor for acquiring the information of the tire, can be securely attached to the inner surface of the tire. 
     Furthermore, when a tire having a sensor module housed in the rubber base attached by the above-mentioned attaching method or having a sensor module mounted on the rubber base attached by the above-mentioned attaching method is used, information of a running tire, such as a tire inner pressure, a tire inner temperature, or vibration input to the tire or a deformation state of the tire, can be stably acquired. 
     REFERENCE SIGN LIST 
       10  tire,  11  inner liner,  12  silicone layer,  20  laser device,  30  tire information acquisition device,  31  rubber base,  32  sensor module.