This application claims the benefit of priority of Japanese application no. 2021-71996, filed on Apr. 21. 2021, which is incorporated herein by reference.
The present disclosure relates to a pneumatic tire.
An insignia that displays the product name, brand name, andor the like might be provided at the sidewall of a pneumatic tire (see, for example, Japanese Patent Application Publication Kokai No. 2010-64656). The insignia is a projection that protrudes toward the exterior in the tire axial direction from the profile surface (hereinafter also referred to as “reference surface”) which is present in the region peripheral thereto. Increasing the amount by which the insignia protrudes from the profile surface will make it possible to improve the visibility of the insignia. However, this will increase the tendency for cracking to occur at the insignia.
The present disclosure provides a pneumatic tire permitting in probed sidewall insignia visibility and resistance to cracking.
According of the present disclosure, there is provided a pneumatic tire having sidewall that extends in a tire radial direction, wherein the sidewall has an insignia which protrudes toward an exterior in a tire axial direction; the insignia has a strip-like body, an endless-loop-like outline which encompasses the body, and a bridge which is arranged toward an exterior from the endless loop of the outline and which causes a mutually separated pair of the outlines to be mutually connected; heights by which the body and the outline protrude relative to a reference surface which is an exterior surface in a region peripheral to the insignia are mutually different; and a height by which the bridge protrudes relative to the reference surface is less than each of the protruding heights of the body and the outline.
Below, a first embodiment in accordance with the present disclosure is described with reference to the drawings.
As shown in
Tire equatorial plane TE refers to a plane that is located centrally in the tire axial direction AD and that is perpendicular to the rotational axis of the tire. Tire meridional planes refer to planes that are perpendicular to tire equatorial plane TE and that contain the rotational axis of the tire. In the tire axial direction AD, toward the interior means nearer to tire equatorial plane TE, and toward the exterior means farther away from tire equatorial plane TE. Furthermore, in the tire radial direction RD, toward the interior means nearer to the tire rotational axis, and toward the exterior means farther away from the tire rotational axis.
Bead region 11 has bead cote 11a which is formed so as to be annular in shape, and bead filler 11b which is arranged toward the exterior in the tire radial direction RD from bead core 11a. Bead core 11a might, for example, be formed by laminating rubber-covered bead wire(s) (e.g. metal wire(s)). Bead filler 11b comprises hard rubber of higher rubber hardness than that of other rubber member(s) adjacent to bead filler 11b, and is formed such that the cross-sectional shape thereof tapers as one proceeds toward the exterior in the tire radial direction RD.
Furthermore, tire PT has carcass 14 suspended between pair of bead cores 11a, and innerliner 15 that is arranged toward the interior in the tire radial direction RD from carcass 14 and that faces the interior space of tire PT which is or will be filled with air. Carcass 14 and innerliner 15 are arranged in parallel fashion with respect to the inside circumferential surface of the tire over a portion thereof that encompasses bead regions 11, sidewalls 12, and tread 13.
Bead region 11 has rim strip rubber 11c arranged toward the exterior in the tire axial direction AD from carcass 14. Rim strip rubber 11c forms the outer surface that will come in contact with the rim. Sidewall 12 has sidewall rubber 12a arranged toward the exterior in the tire axial direction AD from carcass 14. Sidewall rubber 12a forms the outer surface.
Tread 13 has tread rubber 13b which forms tread surface 13a, and a belt (not shown) which is arranged between tread rubber 13b and carcass 14. The belt has a plurality (e.g., four) belt plies (not shown). The belt plies (not shown) have a plurality of belt cords (e.g., organic fiber and/or metal) which are arrayed in parallel fashion, and topping rubber with which the belt cords are covered.
Carcass 14 is made up of at least one carcass ply (not shown). The carcass ply (not shown) folds back upon itself and wraps about bead core 11a so as to envelop bead core 11a. Furthermore, the carcass ply (not shown) has a plurality of ply cords (e.g., organic fiber and/or metal) which are arrayed in direction(s) more or less perpendicular to the tire circumferential direction CD, and topping rubber with which the ply cords are covered. Note that while carcass 14 is shown in abbreviated fashion as a single-dash chain line in
Innerliner 15 has superior functionality in terms of its ability to impede passage of gas therethrough so as to permit air pressure to be maintained. Moreover, the constitution at sidewall 12 may be such that, as is the case in the first embodiment, there is no other member that intervenes between innediner 15 and carcass 14.
Sidewalls 12 have locations 12b at the outer surfaces thereof which are at the same locations in the tire radial direction RD as the locations at which tire width is a maximum (more specifically, the locations at which distance W1 between respective exterior points in the tire axial direction AD of carcass 14 is a maximum). Below, these locations 12b are referred to as tire maximum width locations 12b.
While not shown in the drawings, tread rubber 13b has a plurality of main grooves (not shown) extending continuously in the tire circumferential direction CD along the entire length in the tire circumferential direction CD of tread surface 13a, and a plurality of ancillary grooves 13f, each of which extends to one of the outer ends in the tire axial direction AD.
As shown in
As shown in
Strip-like body 30 displays lines of characters, lines of shapes, and/or lines of symbols. For example, as shown in
Outline 31 is formed so as to appear as an endless loop as seen along a line of sight parallel to the tire axial direction AD. Outline 31 encompasses body 30 from either side thereof in the tire circumferential direction CD, and also from either side thereof in the tire radial direction RD. There is at least one outline 31 provided at each strip-like body 30. As is the case with the “E” shown in
Bridge 32 is arranged toward the exterior from the endless loop(s) of outline(s) 31, and causes mutually separated outlines 31 to be mutually connected. “Toward the exterior from the endless loop” means in a direction that would increase distance to body 30 which is surrounded by endless-loop-like outline 31. Body 30 is toward the interior from the endless loop of outline 31. Where a strip-like body 30 forms closed space(s) 34, said closed space(s) 34 will be toward the exterior from the endless loop of outline 31.
Insignia 3 has at least one separating region which is toward the exterior from the endless loop of outline 31. For example, a separating region might be arranged between two sides of outline 31 which extend in the tire radial direction RD, or might be arranged between two sides of outline 31 which extend in the tire circumferential direction CD, or might be arranged in a closed space 34 encompassed by outline 31, or might be arranged between a first character and a second character which are linearly arrayed in the tire circumferential direction CD.
At the example of
Furthermore, at the example of
As shown in
As shown in
It may be the case that a connecting portion which connects reference surface 12c and second edge 31a of outline 31 has at least one arc, reference surface 12c and second edge 31a of outline 31 being connected without presence of an inflection point.
As shown in
As mentioned above, it is absolutely necessary that there be a curved surface between bridge 32 and outline 31. It is absolutely necessary that there be a curved surface between outline 31 and body 30. This is because if there were no curved surface therebetween, this would cause an inflection point to he formed, which would lead to occurrence of cracking. Radius of curvature of the curved surface between bridge 32 and outline 31 might be not less than 0.2 mm but not greater than 2.0 mm. The significance of this is so as to be on the same order as or less than the difference in protruding heights of outline 31 and bridge 32, described below. Radius of curvature between body 30 and outline 31 might be not less than 0.2 mm but not greater than 1.0 mm. The significance of this is so as to be on the same order as or less than the difference in protruding heights of outline 31 and body 30, described below.
As shown in
Here, because outline 31 has both a constant protruding height region and an arc, the protruding height of outline 31 might be taken to be the minimum protruding height at outline 31.
As shown in
Here, because bridge 32 has both a constant protruding height region and an arc, the protruding height of bridge 32 might be taken to be the minimum protruding height at bridge 32.
It is preferred that the difference between the protruding heights of body 30 and outline 31 be not less than 0.2 mm but not greater than 1.0 mm. Where this difference is less than 0.2 mm, visibility will be poor. Furthermore, if this difference exceeds 1.0 mm, this will tend to cause entrapment of air and lead to introduction of air during vulcanization of the tire.
It is preferred that the difference between the protruding heights of outline 31 and bridge 32 be not less than 0.2 mm but not greater than 2.0 mm. Where this difference is less than 0.2 mm, visibility will be poor. Furthermore, if this difference exceeds 2.0 mm, this will tend to cause occurrence of cracking.
If bridge 32 protrudes more than outline 31, this will improve resistance to cracking but will have the negative consequence of increased tendency for occurrence of bare spots and/or worsening of visibility.
If the protruding heights of body 30 and bridge 32 are the same, visibility will be poor. The protruding heights of body 30 and bridge 32 are therefore made different.
Sidewall 12 may, as is the case in the first embodiment, have annular projection 2 that extends in the tire circumferential direction CD and that protrudes in the tire axial direction AD. Annular projection 2 is arranged toward the exterior in the tire radial direction RD from insignia 3. Annular projection 2 and insignia 3 are mutually separated. Annular projection 2 may, as is the case in the first embodiment, extend continuously in the tire circumferential direction CD along the entire length in the tire circumferential direction CD of sidewall 12.
Furthermore, sidewall 12 may have a plurality of side blocks (not shown) toward the exterior in the tire radial direction RD from insignia 3. The plurality of side blocks may be arranged at spaced intervals in the tire circumferential direction CD such that grooves are straddled therebetween. The plurality of side blocks may be arranged only toward the exterior in the tire radial direction RD from annular projection 2, or may be arranged only toward the interior in the tire radial direction RD from annular projection 2, or may be arranged toward both the interior and the exterior in the tire radial direction RD from annular projection 2. The side blocks and insignia 3 are mutually separated.
Note that the foregoing respective dimensions, positional relationships, and relative magnitudes should be understood to be as measured under normal conditions when tire PT mounted on a normal rim and inflated to normal internal pressure is under no load. A normal rim is that particular rim which is specified for use with a particular tire in the context of the body of standards that contains the standard that applies to the tire in question. This is referred to as a “standard rim” in the case of JATMA, and as a “measuring rim” in the case of TRA or ETRTO.
Normal internal pressure is that air pressure which is specified for use with a particular tire in the context of the body of standards that contains the standard that applies to the tire in question. This is referred to as “maximum air pressure” in the case of JATMA, the maximum value listed in the table entitled “Tire Load Limits at Various Cold Inflation Pressures” in the case of TRA, and as “inflation. pressure” in the case of ETRTO.
(1)
In such case, it is preferred that the difference between the protruding heights of body 30 and outline 31 be not less than 0.2 mm but not greater than 1.0 mm. Where this difference is less than 0.2 mm, visibility will be poor. Furthermore, if this difference exceeds 1.0 mm, this will tend to cause entrapment of air and lead to introduction of air during vulcanization of the tire.
Furthermore, assuming that body 30 and bridge 32 should not have the same protruding height, it is preferred that the difference between the protruding heights of outline 31 and bridge 32 be not less than 0.4 mm but not greater than 3.0 mm. Where this difference is less than 0.4 mm, visibility will be poor. Furthermore, if this difference exceeds 3.0 mm, this will tend to cause occurrence of cracking.
(2) The constitution indicated at (1) is more likely to cause occurrence of entrapment of air at body 30 than is the case at the first embodiment shown in
(3)
Furthermore, as shown in
First character “A” and second character “T” are linearly arrayed in the tire circumferential direction CD. O. This bridge 32 extends in the same direction as the direction in which the first character and the second character are linearly arrayed (the tire circumferential direction CD). Bridge 32 which connects outline 31 of first character “A” and outline 31 of second character “T” may be such that a dimension in the tire circumferential direction CD of said bridge 32 is greater than a dimension thereof in the tire radial direction RD.
(4) Whereas body 30, outline 31, and bridge 32 are respectively provided with constant protruding height regions, they may be provided with flat surfaces instead of constant protruding height regions.
As described above, as in the first embodiment shown in
As a result of adoption of such constitution, because the height by which body 30 protrudes relative to reference surface 12c which is present in the region peripheral to insignia 3 and the height by which endless-loop-like outline 31 which encompasses body 30 protrudes relative to reference surface 12c will be mutually different, the shadow at body 30 and outline 31 will be definite, permitting improvement in visibility. Furthermore, it is often the case that reference surface 12c is present toward the exterior from the endless loop of outline 31, and there are also many situations in which reference surface 12c is present in the separating region between mutually separated outlines 31. Where there is a large difference in height between outline 31 and reference surface 12c of the separating region, it will tend to be the case that an arc cannot be provided at the connecting portion which connects outline 31 and reference surface 12c of the separating region, and that there will be creation of an inflection point at that connecting portion, resulting in the possibility that this could lead to occurrence of cracking.
By therefore—as is the case in the present disclosure—causing bridge 32 which mutually connects outlines 31 to be provided in the separating region, presence of bridge 32 makes it possible to reduce the difference in height between outline 31 and the separating region, and makes it possible for arc(s) to be appropriately arranged at the connecting portion which connects outline 31 and bridge 32, more than would be the case were the constitution such that there was no bridge 32 in the separating region. As a result, it will be possible to suppress occurrence of cracking.
As in the first embodiment shown in
As a result of adoption of such constitution, the tendency for rubber to contact the surface of the portion of the mold that forms outline 31 will be increased and bare spots and introduction of air will be capable of being suppressed during vulcanization of the tire, more than would be the case were the constitution such that height D1 by which body 30 protrudes relative to reference surface 12c is less than height D2 by which outline 31 protrudes relative to reference surface 12c.
As in the first embodiment shown in
As a result of adoption of such constitution, because it will be possible to cause body 30, outline 31, and bridge 32 to respectively be provided with constant protruding height regions, this will make it possible to ensure that body 30, outline 31, and bridge 32 will respectively be of adequate width, and will make it possible to improve visibility.
As in the variations shown in
As a result of adoption of such constitution, whereas the fact that height D1 by which body 30 protrudes relative to reference surface 12c is less than height D2 by which outline 31 protrudes relative to reference surface 12c might otherwise lead to the problem in which there is a tendency for occurrence of entrapment of air during vulcanization of the tire, because serrations are formed at body 30, this creates a tendency for air to follow the serrations and be released therefrom, as a result of which it is possible to suppress introduction of air thereinto. Note that this is because a vent hole for release of air would be provided at the region of the mold which most protrudes (outline 31 at the example of
As in the letter “R” in the first embodiment shown in
There is a tendency for regions within closed spaces 34 formed by lines of characters to become narrow. As a result of adoption of such constitution, notwithstanding that character(s) forming such closed space(s) 34 may be provided on sidewall 12, because at least a portion of closed space(s) 34 are provided with bridge(s) 32, it will be possible to appropriately improve resistance to cracking.
As in the letter “A” in the variations shown in
As a result of adoption of such constitution, not only does dividing portion 33 make it possible to improve visual appearance but the cracking that might otherwise have been produced due to presence of dividing portion 33 is able to be suppressed due to presence of bridge(s) 32.
As in the letter “A” and “T” in the variations shown in
As a result of adoption of such constitution, because the first character and the second character are connected by bridge 32, this makes it possible to improve resistance to cracking.
While embodiments in accordance with the present disclosure have been described above with reference to the drawings, it should be understood that the specific constitution thereof is not limited to these embodiments. The scope of the present disclosure is as indicated by the claims and not merely as described at the foregoing embodiments, and moreover includes all variations within the scope of or equivalent in meaning to that which is recited in the claims.
Structure employed at any of the foregoing embodiment(s) may be employed as desired at any other embodiment(s). The specific constitution of the various components is not limited only to the foregoing embodiment(s) but admits of any number of variations without departing from the gist of the present disclosure.
Number | Date | Country | Kind |
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2021-071996 | Apr 2021 | JP | national |