The present technology pertains to a pneumatic tire. More specifically, the present technology pertains to a pneumatic tire enabling a degree of wear to be easily and accurately recognized.
A conventional tire is disclosed, for example in Japanese Unexamined Patent Application Publication No. H8-258517A that clearly makes a notification of an exchange period for a worn tire, using a groove bottom of a drainage groove of a ground contact patch of a tire and a slip sign disposed on the drainage groove bottom that are color-coded by paint or by fluorescent paint in whole or in part, for easy viewing.
Furthermore, Japanese Unexamined Patent Application Publication No. 2004-203318A discloses a tire that has a tread wear indicator disposed on a groove bottom section of a groove disposed in a tread section. The tread wear indicator includes a surface rubber layer disposed on the surface layer and a different colored rubber layer disposed on the inner side of the surface rubber layer in the radial direction. The surface rubber layer is disposed continuously on the surface layer of the groove bottom section and made from the same rubber material as that forming the groove bottom section, and the different colored rubber layer has a color different from that of the surface rubber layer and that of a rubber section adjacent to the inside of the different colored rubber layer in the radial direction.
Furthermore, Japanese Utility Model No. 3130375 discloses a tire in which a slip sign is made of a rubber column having three colors of blue, light blue, and red and is embedded into a ground contact patch, such that the wear of the tire is identifiable.
Furthermore, Japanese Unexamined Patent Application Publication No. 2006-232152A discloses a tire having a degree of wear indicator that directly indicates a degree of wear by changing in appearance according to the degree of wear of a tread provided in the tread road contact surface. The degree of wear indicator is provided as a plurality of recessed sections varying in depth, each separately disposed in a predetermined row direction in depth order.
The tires disclosed in Japanese Unexamined Patent Application Publication Nos. H8-258517A and 2004-203318A, described above, make a notification of an exchange period by having a slip sign or a tread wear indicator become worn. Conversely, the tires disclosed in Japanese Utility Model No. 3130375 and Japanese Unexamined Patent Application Publication No. 2006-232152A, described above, indicate a degree of wear. However, the tires disclosed in Japanese Utility Model No. 3130375 and Japanese Unexamined Patent Application Publication No. 2006-232152A provide a portion indicating the degree of wear on a road contact surface of a tread. In Japanese Utility Model No. 3130375, a rubber column of a different material than the tread is used. In Japanese Unexamined Patent Application Publication No. 2006-232152A, a recessed section is used. As such, there is a risk of impairing tire performance due to uneven wear of the road contact surface, deterioration in driving stability, and the like.
The present technology provides a pneumatic tire enabling a degree of wear to be easily and accurately recognized without impairing tire performance.
A pneumatic tire according to a first aspect of the technology is a pneumatic tire with a groove in a tread surface, the pneumatic tire including a recessed section provided in a groove wall surface of the groove, and a photoluminescent material adhered to the inside of the recessed section.
According to this pneumatic tire, the photoluminescent material adheres to the groove wall surface of the groove. Thus, a degree of wear of the tread surface is recognizable by the photoluminescent material decreasing or disappearing due to wear of the tread surface. Furthermore, according to this pneumatic tire, the photoluminescent material adheres to the inside of the recessed section. Thus, even when a stone or the like enters the groove, contact with the photoluminescent material is prevented. As such, the photoluminescent material may be prevented from falling out, which in turn enables improvements to anti-abrasion characteristics and anti-weathering characteristics of the photoluminescent material. Therefore, the photoluminescence of the photoluminescent material may be maintained while the degree of wear of the tread surface may be easily and accurately recognized.
Furthermore, the pneumatic tire according to the first aspect of the technology has a step formed in the groove wall surface of the groove in a tire circumferential direction, has a recessed section provided at least in a top surface forming the step, and has a photoluminescent material adhered to the inside of the recessed section in a second aspect of the technology.
According to this pneumatic tire, having the photoluminescent material adhered to the inside of the recessed section provided at least in the top surface of the step enables the visibility of the tread surface to be improved in a plan view, thereby enabling the degree of wear of the tread surface to be easily and accurately recognized.
Furthermore, the pneumatic tire according to the second aspect of the technology has the step provided in plurality in the tire radial direction, has the recessed section provided at least in the top surface of each of the steps, and has the photoluminescent material adhered to the inside of the recessed section in a third aspect of the technology.
According to this pneumatic tire, having the photoluminescent material adhered to the inside of the recessed section provided at least in the top surface of each of a plurality of steps enables the visibility of the tread surface to be improved in a plan view, thereby enabling a degree of wear of the tread surface to be easily and accurately recognized and further enabling the degree of wear of the tread surface to be gradually recognized.
In addition, the pneumatic tire according to any one of the first to third aspects of the technology has a ratio of a major axis H1 of the photoluminescent material to a width H of a bottom surface of the recessed section such that 0.3≦H1/H≦0.95 in a fourth aspect of the technology.
According to this pneumatic tire, the visibility of the photoluminescent material may be enhanced by having H1/H to be at least 0.3. Furthermore, having H1/H to be no more than 0.95 enables the photoluminescent material to fit well into the recessed section and prevents the photoluminescent material from falling out.
Furthermore, the pneumatic tire of any one of the first to fourth aspects of the technology has a depth D of the recessed section such that 0.2 mm≦D≦1.5 mm in a fifth aspect of the technology.
According to this pneumatic tire, having the depth D of the recessed section to be at least 0.2 mm enables the photoluminescent material to fit well into the recessed section and prevents the photoluminescent material from falling out. Furthermore, having the depth D of the recessed section to be no more than 1.5 mm enables the visibility of the photoluminescent material to be improved.
Furthermore, the pneumatic tire according to any one of the first to fifth aspects of the technology has a small projection projecting within the recessed section provided on an inner side surface, closer to an opening side than to the bottom surface of the recessed section in a sixth aspect of the technology.
According to this pneumatic tire, the photoluminescent material adheres to the bottom surface of the recessed section engages with the small projection, thus preventing the photoluminescent material from falling out.
A pneumatic tire according to the present technology enables a degree of wear to be easily and accurately recognized.
Embodiments of the present technology are described in detail below with reference to the accompanying drawings. However, no limitation of the present technology is intended by the embodiments. Furthermore, components of the embodiments include elements that may be easily replaced by those skilled in the art or that are substantially identical to components of the embodiments. Furthermore, a plurality of modified examples described in the embodiments may be combined as desired within the scope of obviousness by those skilled in the art.
As illustrated in
The tread portion 2 is formed from a rubber material (tread rubber) and is exposed on the outermost side in the tire radial direction of the pneumatic tire 1, such that a surface thereof constitutes a profile of the pneumatic tire 1. A tread surface 21 is formed on an outer peripheral surface of the tread portion 2 or, rather, on a road contact surface that comes in contact with a road surface during driving. The tread surface 21 has a plurality (four in the embodiments) of main grooves 22 provided therein, extending in the tire circumferential direction, the main grooves 22 being straight main grooves parallel to the tire equatorial line CL. Moreover, a plurality of rib-like land portions 23 extending in the tire circumferential direction and parallel to the tire equatorial line CL is formed in the tread surface 21 by the plurality of main grooves 22. Also, the rib-like land portions 23 in the tread surface 21 are provided with lug grooves 24 that intersect the main grooves 22, such that the land portions 23 are divided in plurality in the tire circumferential direction so as to form block-like land portions 23a (see
The shoulder portions 3 are locations on both outer sides in the tire width direction of the tread portion 2. Additionally, the side wall portion 4 is exposed on the outermost side of the pneumatic tire 1 in the tire width direction. The bead portion 5 includes a bead core 51 and a bead filler 52. The bead core 51 is formed by winding a bead wire, which is a steel wire, into an annular shape. The bead filler 52 is a rubber material that is disposed in space formed by an end of the carcass layer 6 in the tire width direction being folded back at the position of the bead core 51.
The ends of the carcass layer 6 in the tire width direction are folded over the pair of bead cores 51 from the inner side in the tire width direction to the outer side in the tire width direction, and the carcass layer 6 is stretched in a toroidal shape in the tire circumferential direction to form the framework of the tire. The carcass layer 6 is constituted by a plurality of carcass cords (not illustrated) disposed parallel in the tire circumferential direction along a tire meridian direction at a given angle with respect to the tire circumferential direction and covered by a coating rubber. The carcass cords are formed from organic fibers (e.g., polyester, rayon, nylon, or the like). At least one layer of this carcass layer 6 is provided.
The belt layer 7 has a multi-layer structure in which at least two layers (belts 71 and 72) are laminated; is disposed on an outer side in the tire radial direction that is the periphery of the carcass layer 6, in the tread portion 2; and covers the carcass layer 6 in the tire circumferential direction. The belts 71 and 72 include a plurality of cords (not illustrated) disposed parallel at a predetermined angle with respect to the tire circumferential direction (e.g., from 20 degrees to 30 degrees), and covered by a coating rubber. The cords are formed from steel or organic fibers (e.g. polyester, rayon, nylon, or the like). Moreover, the belts 71 and 72 that overlap each other are disposed so that the respective cords intersect each other.
The belt reinforcing layer 8 is disposed on the outer side in the tire radial direction at the periphery of the belt layer 7, and covers the belt layer 7 in the tire circumferential direction. The belt reinforcing layer 8 includes a plurality of cords (not illustrated) disposed parallel in the tire width direction and substantially parallel (±5 degrees) to the tire circumferential direction, which are covered by a coating rubber. The cords are formed from steel or organic fibers (e.g. polyester, rayon, nylon, or the like). The belt reinforcing layer 8 illustrated in
As illustrated in
The recessed section 9 illustrated in
The recessed section 9 illustrated in
The recessed section 9 illustrated in
Also, the recessed section 9 illustrated in
The photoluminescent material 10 adheres, to the inside of the recessed section 9, to an inner surface of the recessed section 9 (a bottom surface 9a or an inner side surface 9b: see
Also, in
As such, the pneumatic tire 1 of the present embodiment is a pneumatic tire 1 having the main groove 22 (lug groove 24) in the tread surface 21. The recessed section 9 is provided in the groove wall surface 22a of the main groove 22 (lug groove 24), and the photoluminescent material 10 adheres to the inside of the recessed section 9.
According to this pneumatic tire 1, the photoluminescent material 10 adheres to the groove wall surface 22a of the main groove 22. Thus, a degree of wear of the tread surface 21 is recognizable by the photoluminescent material 10 decreasing or disappearing due to wear of the tread surface 21. Furthermore, according to this pneumatic tire 1, the photoluminescent material 10 adheres to the inside of the recessed section 9. Thus, even when a stone or the like enters the main groove 22 (lug groove 24), contact with the photoluminescent material 10 is prevented. As such, the photoluminescent material 10 may be prevented from falling, which also enables improvements to anti-abrasion characteristics and anti-weathering characteristics of the photoluminescent material 10. Therefore, the photoluminescence of the photoluminescent material 10 may be maintained while the degree of wear of the tread surface 21 is easily and accurately recognizable.
Here, as illustrated in
Also, as illustrated in
Furthermore, having the innermost portion in the tire radial direction of the recessed section 9 with the photoluminescent material 10 adhering thereto be the same in terms of height as the position of a wear indicator indicating a tire exchange period enables the exchange period to be recognized by the luminescence of the photoluminescent material 10 disappearing.
As illustrated in
The recessed section 9 provided in the step 11 illustrated in
The recessed section 9 provided in the step 11 illustrated in
The recessed section 9 provided in the step 11 illustrated in
Here, the step 11 and the recessed section 9 illustrated in
The photoluminescent material 10 adheres, to the inside of the recessed section 9, to an inner surface of the recessed section 9 (a bottom surface 9a or an inner side surface 9b: see
Also, in
As such, the pneumatic tire 1 of the present embodiment is a pneumatic tire 1 having a main groove 22 (lug groove 24) in a tread surface 21. A recessed section 9 is provided in the groove wall surface 22a of the main groove 22 (lug groove 24), and a photoluminescent material 10 adheres to the inside of the recessed section 9.
According to this pneumatic tire 1, the photoluminescent material 10 adheres to the groove wall surface 22a of the main groove 22. Thus, a degree of wear of the tread surface 21 is recognizable by the photoluminescent material 10 decreasing or disappearing due to wear of the tread surface 21. Furthermore, according to this pneumatic tire 1, the photoluminescent material 10 adheres to the inside of the recessed section 9. Thus, even when a stone or the like enters the main groove 22 (lug groove 24), contact with the photoluminescent material 10 is prevented. As such, the photoluminescent material 10 may be prevented from falling, which also enables improvements to anti-abrasion characteristics and anti-weathering characteristics of the photoluminescent material 10. Therefore, the photoluminescence of the photoluminescent material 10 may be maintained while the degree of wear of the tread surface 21 is easily and accurately recognizable.
Furthermore, the pneumatic tire 1 of the present embodiment has the step 11 formed in the groove wall surface 22a of the main groove 22 (lug groove 24) in the tire circumferential direction. The recessed section 9 is provided at least in the top surface 11a forming the step 11, and the photoluminescent material 10 adheres to the inside of the recessed section 9.
According to this pneumatic tire 1, having the photoluminescent material 10 adhere to the inside of the recessed section 9 provided at least in the top surface 11a of the step 11 enables the visibility of the tread surface 21 to be improved in a plan view, thereby enabling a degree of wear of the tread surface 21 to be easily and accurately recognized.
Here, having the position in the tire radial direction of the step 11 (top surface 11a) having the recessed section 9 with the photoluminescent material 10 adhering thereto to be the same in terms of height as the position of a wear indicator indicating a tire exchange period enables the exchange period to be recognized by the luminescence of the photoluminescent material 10 disappearing.
Also, it is preferable that the pneumatic tire 1 of the present embodiment have the step 11 provided in plurality in the tire radial direction, have the recessed section 9 provided at least in the top surface 11a of each such step 11, and have the photoluminescent material 10 adhere to the inside of the recessed section 9.
According to this pneumatic tire 1, having the photoluminescent material 10 adhere to the inside of the recessed section 9 provided at least in the top surface 11a of each of the plurality of steps 11 enables the visibility of the tread surface 21 to be improved in a plan view, thereby enabling a degree of wear of the tread surface 21 to be easily and accurately recognized and further enabling the degree of wear of the tread surface 21 to be gradually recognized.
Also, in a case in which the step 11 is provided in plurality, the color of the photoluminescent material 10 may vary for each of the steps 11, thus enabling a gradual degree of wear of the tread surface 21 to be easily and accurately recognized. Here, having the innermost step 11 in the tire radial direction, among the plurality of steps 11 (top surfaces 11a) each having the recessed section 9 with the photoluminescent material 10 adhering thereto disposed at a position having the same height as that of a wear indicator indicating a tire exchange period enables the exchange period to be recognized by the luminescence of the photoluminescent material 10 disappearing.
The width H of the bottom surface of the recessed section 9 is found by taking the deepest portion of the recessed section 9 as the bottom surface 9a, as illustrated in
According to this pneumatic tire 1, the visibility of the photoluminescent material 10 is improved by having H1/H be at least 0.3. Also, having H1/H be no more than 0.95 enables the photoluminescent material 10 to fit well within the recessed section 9 and prevents the photoluminescent material 10 from falling out.
Furthermore, in embodiment 1 and embodiment 2 as described above, as illustrated in
According to this pneumatic tire 1, having the depth D of the recessed section 9 be at least 0.2 mm enables the photoluminescent material 10 to fit well within the recessed section 9 and prevents the photoluminescent material 10 from falling out. Also, having the depth D of the recessed section 9 be no more than 1.5 mm enables the visibility of the photoluminescent material 10 to be improved.
In addition, in embodiment 1 and embodiment 2 described above, as illustrated in
According to this pneumatic tire 1, as illustrated by
In manufacturing the pneumatic tire 1 according to any one of embodiment 1 to embodiment 3, the photoluminescent material 10 is made to adhere to the inside of the recessed section 9 after vulcanization of the pneumatic tire 1 having the recessed section 9. Accordingly, the above-described pneumatic tire 1 may be obtained.
According to this manufacturing method for the pneumatic tire 1, the photoluminescent material 10 is pressure-bonded onto an inner surface (i.e., the bottom surface 9a or the inner side surface 9b) of the recessed section 9 by a solid body. Accordingly, this enables good adhesion for the photoluminescent material 10. Here, the solid body may have a shape conforming to the inner surface shape of the recessed section 9 in order to ensure close contact with the inner surface of the recessed section 9. For example, in a case in which the recessed section 9 is formed of a groove, using a disc-like roller that conforms to the groove enables the pressure-bonding work to be performed simply.
Also, according to the above-described manufacturing method for the pneumatic tire 1, a buffing process may be applied to the surface where the recessed section 9 is provided (i.e., the groove wall surface 22a or the top surface 11a of the step 11) upon adhesion of the photoluminescent material 10 to the inner surface of the recessed section 9, such that any excess of the photoluminescent material 10 adhering to a position outside the recessed section 9 (i.e., the groove wall surface 22a or the top surface 11a of the step 11) may be removed. That is, given that the photoluminescent material 10 adhering to the position outside the recessed section 9 is easy to remove, removing such excess in advance enables a stable state to be ensured for the photoluminescent material 10 in the long term. Also, external appearance may be improved in cases in which the photoluminescent material 10 adhering to the position outside the recessed section 9 is removed.
According to the present embodiment, the photoluminescent material 10 is required to adhere to the inside of the recessed section 9. However, more specifically, the photoluminescent material 10 preferably sticks inside the recessed section 9. For example, the photoluminescent material 10 may be mixed with an adhesive having adhesive properties in liquid form or in gel form. This enables the adhesive that includes the photoluminescent material 10 to be applied to the recessed section 9. Alternatively, an adhesive may be applied to the recessed section 9 in advance. This enables the photoluminescent material 10 to adhere superposed on the adhesive.
In these working examples, a variety of pneumatic tires under different conditions were used in performance testing pertaining to visibility and discoloration resistance properties (see
In the performance testing, pneumatic tires having a tire size of 195/65R15 were assembled on a regular rim (15×6J), inflated to a regular inner pressure (230 kPa), and mounted on a test vehicle (1.4 L, front-wheel-drive vehicle, manufactured in Japan).
Here, “regular rim” refers to a “standard rim” defined by the Japan Automobile Tyre Manufacturers Association Inc. (JATMA), “Design Rim” defined by the Tire and Rim Association, Inc. (TRA), or “Measuring Rim” defined by the European Tyre and Rim Technical Organisation (ETRTO). Furthermore, “regular inner pressure” refers to “maximum air pressure” defined by JATMA, a maximum value described in “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES” defined by TRA, or “INFLATION PRESSURES” defined by ETRTO.
The evaluation method for the visibility involves driving the above-described test vehicle on a dry road surface for 1000 km, then having each of ten panelists visually confirm wear conditions of the tread surface, and measuring the time required to confirm the wear conditions. The average time of the measurement results is evaluated. In this evaluation, a shorter time corresponds to preferable higher visibility.
The evaluation method for the discoloration resistance properties involves driving the above-described test vehicle on a dry road surface for 1000 km, then having each of ten panelists visually confirm the wear conditions of the tread surface, taking an average evaluation as an evaluation grade, and taking an index value in which conventional example 1 serves as a standard (100). In this evaluation a greater index corresponds to preferable maintained visibility, and high discoloration resistance properties.
In
In
In
In
In
As shown by the evaluation results in
Number | Date | Country | Kind |
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2013-002790 | Jan 2013 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2013/084909 | 12/26/2013 | WO | 00 |