JP5794249B2 - Pneumatic tire and tire mold - Google Patents

Description

  The present invention relates to a pneumatic tire and a tire molding die mounted on a vehicle.

  BACKGROUND ART A pneumatic tire mounted on a vehicle such as an automobile includes a tire having a so-called serration, which is a portion in which a large number of ridges composed of small linear convex portions are formed at short intervals on a sidewall portion of the tire. Various types of serrations have been proposed. For example, Patent Document 1 describes a serration having a ridge whose angle changes depending on the position in the tire radial direction. Patent Document 2 describes serrations in which two types of ridges having different shapes are alternately arranged. Patent Document 3 describes a serration in which two types of ridges having different heights are arranged. Further, Patent Document 4 describes serrations in which the ridge arrangement interval (roughness) is changed depending on the position.

JP-A-11-198614 JP-A-12-280716 JP-A-8-318716 Japanese Patent Laid-Open No. 7-164831

  As described in Patent Documents 1 to 4, the pneumatic tire can improve the design of the tire or make the unevenness of the sidewall portion inconspicuous by forming serrations in various shapes. However, even with the serrations described above, the quality of the appearance may not be sufficiently improved. In addition, unevenness of tire sidewalls, specifically, camouflage unevenness of a carcass splice part or a carcass winding-up part may be insufficient.

  This invention is made | formed in view of the above, Comprising: It aims at providing the pneumatic tire which can make the quality of the external appearance of a tire high, and the tire shaping die which shape | molds this pneumatic tire.

  In order to solve the above-described problems and achieve the object, the present invention is a pneumatic tire including a tread portion, a sidewall portion, and a bead portion, and the sidewall portion is arranged in the tire radial direction. The fixed region has a decoration region in which a plurality of ridges that are convex on the outer surface and extend in the first direction are arranged adjacent to each other in the second direction intersecting the first direction, and the ridge includes the first ridge. A cross-sectional shape in a direction orthogonal to the direction continuously changes from one end portion to the other end portion in the first direction.

  The first direction is preferably the tire radial direction, and the second direction is preferably a tire circumferential direction.

  The first direction is preferably a direction having an inclination angle with respect to the tire radial direction within 90 degrees.

  The ridge has an angle formed by a line connecting the reference point and the target position with a reference point of the cross-sectional shape as an axis, and a line passing through the reference point and orthogonal to the surface of the sidewall portion. It is preferable that it continuously changes from one end in the first direction toward the other end.

  In addition, it is preferable that the decorative region gradually changes between a position in the first direction where the angles formed by the ridges are the same and a ridge adjacent in the second direction.

  Moreover, it is preferable that the angle formed by the ridge is 10 degrees or more and 30 degrees or less.

  Further, it is preferable that the angle formed by the ridge is changed by one period from one end portion to the other end portion in the first direction.

  In addition, it is preferable that the angle formed by the ridge changes from one end to the other end in the first direction more than one period.

  In the ridge, it is preferable that the reference point is a midpoint of an end portion of the cross-sectional shape in the second direction, and the target position is a top portion of the cross-sectional shape.

  In the ridge, the reference point is the top of the cross-sectional shape, and the midpoint of the line connecting the points at the same distance from the top on the side where the target position is connected to both ends of the top. It is preferable that

  Moreover, it is preferable that the position of the edge part of the said ridge of the said 2nd direction of the said cross-sectional shape changes continuously from one edge part of the said 1st direction toward the other edge part.

  Moreover, it is preferable that the position of the top part of the said cross-sectional shape of the said ridge changes continuously toward the other end part from the one end part of the said 1st direction.

  Moreover, it is preferable that the said decoration area | region is provided with two or more decoration parts provided with the said several ridges whose said 1st direction is the same direction, and the said decoration part differs in the said 1st direction from the said adjacent decoration part.

  Moreover, it is preferable that the said decoration area | region is arrange | positioned at the perimeter of a tire circumferential direction.

  In order to solve the above-described problems and achieve the object, the present invention provides a tire molding die for molding the pneumatic tire according to any one of the above, wherein the sidewall portion is formed on an inner peripheral surface. A sidewall portion forming portion, wherein the sidewall portion forming portion includes a plurality of grooves that are concave in the inner peripheral surface and extend in the first direction in a certain region in the tire radial direction, intersecting the first direction. The groove has a ridge-forming region disposed adjacent to two directions, and the groove has a cross-sectional shape in a direction orthogonal to the first direction from one end of the first direction to the other end. It is characterized by continuously changing.

  The pneumatic tire according to the present invention and the tire molding die for molding the pneumatic tire have an effect of improving the quality of the appearance of the pneumatic tire.

FIG. 1 is a side view of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a perspective view showing a serration portion of the pneumatic tire shown in FIG. 3A is a cross-sectional view taken along line AA of FIG. 3B is a cross-sectional view taken along line BB in FIG. 3C is a cross-sectional view taken along the line CC of FIG. FIG. 4 is a side view of a pneumatic tire according to a reference example. FIG. 5 is a perspective view showing a serration portion of the pneumatic tire shown in FIG. 4. 6 is a cross-sectional view taken along line Aa-Aa, line Ba-Ba and line Ca-Ca in FIG. FIG. 7A is a perspective view illustrating a schematic configuration of a ridge according to a modification. FIG. 7B is a front view of the ridge shown in FIG. 7A. FIG. 8A is a perspective view illustrating a schematic configuration of a ridge according to a modification. FIG. 8B is a front view of the ridge shown in FIG. 8A. FIG. 9 is a front view showing a schematic configuration of a ridge according to a modification. FIG. 10 is a front view showing a schematic configuration of a ridge according to a modification. FIG. 11 is a side view of a pneumatic tire according to another embodiment. 12 is a perspective view showing a serration portion of the pneumatic tire shown in FIG. 13A is a cross-sectional view taken along the line Ab-Ab in FIG. 13B is a cross-sectional view taken along line Bb-Bb in FIG. 13C is a cross-sectional view taken along line Cb-Cb in FIG. FIG. 14 is a side view of a pneumatic tire according to another embodiment. FIG. 15 is a side view of a pneumatic tire according to another embodiment. FIG. 16 is a side view of a pneumatic tire according to another embodiment. FIG. 17 is a side view of a pneumatic tire according to another embodiment. 18 is an enlarged view in which the serration portion of the pneumatic tire shown in FIG. 17 is enlarged. FIG. 19 is a side view of a pneumatic tire according to another embodiment. FIG. 20 is a cross-sectional view in the meridian direction showing the tire molding die according to the present embodiment. FIG. 21 is a side view showing a ridge forming region of the tire molding die. 22A is a cross-sectional view taken along line Ac-Ac in FIG. 22B is a cross-sectional view taken along line Bc-Bc in FIG. 22C is a cross-sectional view taken along line Cc-Cc in FIG. FIG. 23A is an explanatory diagram for explaining a method of manufacturing the tire molding die. FIG. 23B is an explanatory diagram for explaining a method of manufacturing the tire molding die. FIG. 24A is an explanatory diagram for explaining a method of manufacturing a tire molding die. FIG. 24B is an explanatory diagram for explaining a method of manufacturing the tire molding die. FIG. 25 is a perspective view illustrating a schematic configuration of the pneumatic tire of the first embodiment. FIG. 26 is a perspective view illustrating a schematic configuration of the serration unit according to the first embodiment. FIG. 27 is a perspective view illustrating a schematic configuration of the pneumatic tire of the second embodiment. FIG. 28 is a perspective view illustrating a schematic configuration of the serration unit according to the second embodiment. FIG. 29 is a perspective view illustrating a schematic configuration of the pneumatic tire of the third embodiment. FIG. 30 is a perspective view illustrating a schematic configuration of the serration unit according to the third embodiment. FIG. 31 is a perspective view illustrating a schematic configuration of a serration portion of a pneumatic tire of a comparative example. FIG. 32 is a perspective view showing a schematic configuration of a serration portion of a pneumatic tire of a comparative example. FIG. 33 is a perspective view illustrating a schematic configuration of a serration portion of the pneumatic tire of the example. FIG. 34 is a perspective view illustrating a schematic configuration of a serration portion of the pneumatic tire of the example.

  Embodiments of the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. The constituent elements of this embodiment include those that can be easily replaced by those skilled in the art or those that are substantially the same. Further, a plurality of modifications described in this embodiment can be arbitrarily combined within the scope obvious to those skilled in the art.

  In the following description, the axial direction of the rotating shaft is defined as the Z-axis direction. Further, the tire width direction refers to a direction parallel to the rotation axis (not shown) of the pneumatic tire 1. The outer side in the tire width direction refers to the side away from the tire equator plane (tire equator line) in the tire width direction. The tire circumferential direction is a circumferential direction (Zθ direction in the figure) with the rotation axis as the central axis. Further, the tire radial direction is a direction around the rotation axis on the XY plane. The tire radial direction means a direction orthogonal to the rotation axis, the tire radial direction inner side means the side toward the rotation axis in the tire radial direction, and the tire radial direction outer side means the side away from the rotation axis in the tire radial direction.

  Here, FIG. 1 is a side view of the pneumatic tire according to the embodiment of the present invention. FIG. 2 is a perspective view showing a serration portion of the pneumatic tire shown in FIG. 3A is a cross-sectional view taken along line AA of FIG. 3B is a cross-sectional view taken along line BB in FIG. 3C is a cross-sectional view taken along the line CC of FIG. As shown in FIG. 1, the pneumatic tire 1 includes a tread portion 2 that is in contact with a road surface, and a side that can be visually recognized at the outermost side in the tire width direction when the pneumatic tire 1 is assembled on a rim 6 and mounted on a vehicle. The wall portion 3 and the bead portion 4 that fits with the rim 6 when assembled to the rim 6 are configured.

  As shown in FIG. 1, the sidewall portion 3 has a serration portion 5 on the surface thereof. The serration portion 5 is formed in a shape extending along the tire circumferential direction in a predetermined range in the tire radial direction of the sidewall portion 3, that is, in an annular shape. The serration portion 5 basically has an end portion (carcass) in which a carcass (not shown) forming a skeleton of the pneumatic tire 1 is folded back by a bead portion 4 in a predetermined region in the tire radial direction, at the outermost position in the tire width direction. It is provided in a region including the position of the winding portion) and the portion where the carcass overlaps (carcass splice portion).

  As shown in FIGS. 1 and 2, the serration portion 5 is an annular region surrounded by an inner ring 16 and an outer ring 18, and has a large number of ridges 12. In the present embodiment, the region where the ridge 12 is formed is defined as a decoration region. In the serration portion 5 of the present embodiment, since the ridge 12 is formed in the entire annular area surrounded by the inner ring 16 and the outer ring 18, the annular area surrounded by the inner ring 16 and the outer ring 18 is All are decorative areas. The serration unit 5 has a mark formation region 14. The mark formation region 14 is a region where characters for identifying tires, product names, and the like are formed. The character or the like formed in the mark forming region 14 may be expressed by the shape of the protrusion formed on the sidewall portion 3 or the shape of the recess. In the serration portion 5 of the present embodiment, the ridge 12 is also disposed in the mark formation region 14. As the mark formation region 14, the shape and recess of the protrusion formed on the sidewall portion 3 may be formed so as to overlap the ridge 12, or the shape of a part of the ridge 12 may be adjusted. For example, the ridge 12 of the outline portion of the character to be formed may be cut to form a recess to display the outline of the character.

  Next, the shape of the ridges 12 arranged in large numbers in the serration portion 5 will be described. The ridge 12 is a protrusion protruding in the tire width direction, and extends in an arbitrary direction (first direction) on the tire surface. The ridge 12 of the present embodiment extends from the inner ring 16 to the outer ring 18 in the tire radial direction. That is, the ridge 12 extends over the entire radial direction of the serration portion 5. The serration portion 5 is disposed adjacent to the direction in which the ridge 12 intersects the extending direction, in this embodiment, the circumferential direction (Zθ direction). That is, in the serration unit 5, the plurality of ridges 12 are arranged in a row in a direction substantially orthogonal to the extending direction.

  As shown in FIGS. 2 and 3A to 3C, the ridge 12 has a cross-sectional shape in a direction orthogonal to the extending direction that is convex with respect to the surface of the sidewall portion 3, that is, protrudes outward in the tire width direction. It becomes a shape. The ridge 12 includes a top portion 20 that is the portion farthest from the surface of the sidewall portion 3, and side edges 22 that are provided at both ends of the top portion 20 and are connected to the surface of the sidewall portion 3. Further, a point where the side 22 and the surface of the sidewall portion 3 are connected, that is, an end portion of the ridge 12 is defined as an end portion 23. Further, since the ridge 12 extends in the tire radial direction (first direction), the top portion 20 becomes the top surface 20, the side 22 becomes the side 22, and the end 23 becomes the end 23.

  As shown in FIG. 2 and FIGS. 3A to 3C, the ridge 12 has a cross-sectional shape in a direction orthogonal to the extending direction depending on the position in the extending direction. That is, the cross-sectional shape of the ridge 12 continuously changes from one end portion (inner ring 16) in the extending direction toward the other end portion (outer ring 18). In the ridge 12 of this embodiment, the cross-sectional shape of one end portion (inner ring 16) in the extending direction is such that the top portion 20 is inclined to one side (left side in FIG. 3A) as shown in FIG. The side 22 on the side is shorter than the side 22 on the other side. In the ridge 12, the cross-sectional shape of the other end portion (outer ring 18) in the extending direction is such that the top portion 20 is inclined to the other side (right side in FIG. 3B) as shown in FIG. 22 is shorter than the side 22 on one side. In addition, the cross-sectional shape of the ridge 12 at the position indicated by the target shape line 26 near the center in the extending direction is a symmetrical shape as shown in FIG. 3C. Thus, the ridge 12 has a shape in which the top surface 20 moves from the left side to the right side in FIG. 2 from one end (inner ring 16) toward the other end (outer ring 18). The ridge 12 has a shape in which the end side 23 is parallel to the radial direction. That is, in the ridge 12, the end of the formation region in the tire circumferential direction (second direction) is the same regardless of the position in the tire radial direction, and the position of the top surface 20 varies depending on the position in the tire radial direction. The cross-sectional shape continuously changes from one end in the tire radial direction toward the other end.

  In the ridge 12, ridges having the same shape are arranged in the tire circumferential direction at predetermined intervals in the tire circumferential direction. Here, it is preferable that the arrangement pitch of the ridges is 0.8 mm or more and 3.0 mm or less and at equal intervals. By setting the arrangement pitch of the ridges within the above range, the ridges can be arranged at appropriate intervals in the decoration region, and moire can be suitably generated.

  The pneumatic tire 1 is configured as described above. The pneumatic tire 1 includes a serration portion 5 in which a plurality of ridges 12 are formed in a sidewall portion 3, and the ridge 12 is directed from one end portion in the tire radial direction (first direction) to the other end portion. Thus, by continuously changing the cross-sectional shape, it is possible to cause light gradation (gradation) in the serration portion 5 appropriately. Thereby, the pattern of the serration part 5 can be made more conspicuous and the design property of a pneumatic tire can be made high.

  Further, the pneumatic tire 1 is provided at the outermost position in the tire width direction, and is an end portion (carcass winding portion) where a carcass (not shown) constituting the skeleton of the pneumatic tire 1 is folded back at the bead portion 4. By providing the serration portion 5 in the region including the position and the portion where the carcass overlaps (carcass splice portion), the carcass winding portion and the side of the carcass splice portion are improved while improving the appearance of the outermost side in the tire width direction (sidewall portion 3). The bulge on the surface of the wall portion 3 can be made inconspicuous.

  Here, FIG. 4 is a side view of the pneumatic tire according to the reference example. FIG. 5 is a perspective view showing a serration portion of the pneumatic tire shown in FIG. 4. 6 is a cross-sectional view taken along line Aa-Aa, line Ba-Ba and line Ca-Ca in FIG. The pneumatic tire 101 shown in FIG. 4 includes a tread portion 102 that comes into contact with a road surface, and a sidewall portion 103 that can be visually recognized at the outermost side in the tire width direction when the pneumatic tire 101 is assembled on a rim 106 and mounted on a vehicle. And a bead portion 104 fitted to the rim 106 when the rim 106 is assembled to the rim 106.

  As shown in FIG. 4, the sidewall portion 103 has a serration portion 105 on the surface thereof. The serration portion 105 is formed in a shape extending along the tire circumferential direction in a predetermined range in the tire radial direction of the sidewall portion 103, that is, in an annular shape. The serration unit 105 has a mark formation region 114. As shown in FIGS. 4 and 5, the serration portion 105 is an annular region surrounded by the inner ring 116 and the outer ring 118, and has a large number of ridges 112. The ridge 112 of the pneumatic tire 101 is in a direction orthogonal to the extending direction (first direction) as shown in FIG. 5 and FIG. 6 of the cross-sectional views of the Aa-Aa line, Ba-Ba line, and Ca-Ca line. The cross-sectional shape is the same. As shown in FIGS. 5 and 6, the ridge 112 has a cross-sectional shape in a direction orthogonal to the extending direction that is convex with respect to the surface of the sidewall portion 103, that is, a shape protruding outward in the tire width direction. . The ridge 112 includes a top portion 120 that is the portion farthest from the surface of the sidewall portion 103, and side edges 122 that are provided at both ends of the top portion 120 and are connected to the surface of the sidewall portion 103. Further, a point where the side edge 122 and the surface of the sidewall portion 103 are connected, that is, an end portion of the ridge 112 is defined as an end portion 123. Further, since the ridge 112 extends in the tire radial direction (first direction), the top portion 120 becomes the top surface 120, the side side 122 becomes the side surface 122, and the end portion 123 becomes the end side 123. The ridge 112 has two sides 122 having the same shape, and has a cross-sectional shape that passes through the midpoint of the top portion 120 and has a symmetrical shape with a line perpendicular to the surface of the sidewall portion 103 as an axis.

  Further, in the pneumatic tire 1, like the pneumatic tire 101, in the serration portion 105 including the ridge 112 whose cross-sectional shape does not change, the serration portion 5 can show the light intensity that cannot be shown to the observer. . Thereby, the pneumatic tire 1 can make the design nature of the serration part 105 higher by the shape of the ridge 12, and can make the function as a serration part higher.

  Further, the pneumatic tire 1 adheres foreign matter to the serration portion 5 by continuously changing the cross-sectional shape of the ridge 12 from one end portion in the tire radial direction (first direction) toward the other end portion. Can be difficult.

  Here, the ridge 12 only needs to have a shape in which the cross-sectional shape gradually changes when the position is moved along the extending direction, and can be changed according to various rules. Hereinafter, modified examples of the ridge will be described with reference to FIGS. 7A to 10.

  FIG. 7A is a perspective view illustrating a schematic configuration of a ridge according to a modification. FIG. 7B is a front view of the ridge shown in FIG. 7A. The ridge 212a shown in FIGS. 7A and 7B includes a top portion 220a that is the portion farthest from the surface of the sidewall portion, and a side 222a that is provided at each end of the top portion 220a and connected to the surface of the sidewall portion. Have. Further, a point where the side 222a and the surface of the sidewall portion are connected, that is, an end portion of the ridge 212a is defined as an end portion 223a. Since the ridge 212a also extends in the tire radial direction (first direction), the top 220a becomes the top surface 220a, the side 222a becomes the side 222a, and the end 223a becomes the end 223a.

  In the ridge 212a, the top surface 220a has a shape parallel to the tire radial direction, and a reference line 230a connecting the midpoints in the direction orthogonal to the extending direction of the top surface 220a has a shape parallel to the tire radial direction. The ridge 212a has a shape in which the end side 223a moves from the left side to the right side in FIG. 7B from one end in the extending direction to the other end. In the ridge 212a, the angle formed by the top surface 220a and the side surface 222a is constant. That is, the ridge 212a has a shape in which the direction of the same cross-sectional shape is changed with the reference line 230a as a fulcrum. In the ridge 212a, the position of the center of the top surface 220a is constant, and the positions of the top surface 220a, the side surface 222a, and the end side 223a with respect to the reference line 230a vary depending on the position in the tire radial direction, so that the cross-sectional shape is in the tire radial direction. It continuously changes from one end to the other end. Specifically, as shown in FIGS. 7A and 7B, the angle formed by a line passing through the reference line 230a and perpendicular to the surface of the sidewall portion and connecting the reference line 230a and the target position gradually varies.

  As shown in FIGS. 7A and 7B, the ridge 212a has a side line 222a that has a reference line (reference point in the cross-sectional shape) 230a as the top of the cross-sectional shape and the target position is connected to both ends of the top 220a. As the midpoint of the line connecting the points of the same distance from each other, the shape changes in shape depending on the position in the extending direction, so that the cross-sectional shape in the extending direction can be gradually changed.

  The ridge preferably has the shape shown in FIGS. 7A and 7B, but at least the position of the end portion in the direction (second direction) perpendicular to the extending direction of the cross-sectional shape is in the extending direction (first direction). It is only necessary to continuously change from one end to the other end.

  FIG. 8A is a perspective view illustrating a schematic configuration of a ridge according to a modification. FIG. 8B is a front view of the ridge shown in FIG. 8A. The ridge 212b shown in FIGS. 8A and 8B has a top 220b and a side 222b. Further, a point where the side 222b and the surface of the sidewall portion are connected, that is, an end portion of the ridge 212b is defined as an end portion 223b. Further, since the ridge 212b also extends in the tire radial direction (first direction), the top 220b becomes the top surface 220b, the side 222b becomes the side 222b, and the end 223b becomes the end 223b.

  Similarly to the ridge 12, the position of the top surface 220b of the ridge 212b varies depending on the position in the tire radial direction. The ridge 212b is a line whose end side 223b is parallel to the extending direction. In the ridge 212b, the end of the formation region in the tire circumferential direction (second direction) is the same regardless of the position in the tire radial direction. Therefore, the reference line 230b connecting the midpoints in the direction orthogonal to the extending direction of the top surface 220b of the two end sides 223b has a shape parallel to the tire radial direction. In the ridge 212b, the position of the top surface 220b varies depending on the position in the tire radial direction, so that the cross-sectional shape continuously changes from one end to the other end in the tire radial direction.

  In this way, the ridge 212b is a shape in which the reference point is the midpoint of the end in the second direction of the cross-sectional shape, the target position is the top 220b of the cross-sectional shape, and the position of the target position is shifted with respect to the reference point It becomes. Thereby, a cross-sectional shape changes continuously toward the other end from one end in the tire radial direction. Further, as shown in FIGS. 8A and 8B, the angle formed by the line passing through the reference line 230b and perpendicular to the surface of the sidewall portion and the line connecting the reference line 230b and the target position gradually varies.

  Although the ridge preferably has the shape shown in FIGS. 8A and 8B, at least the position of the top of the cross-sectional shape is continuous from one end in the extending direction (first direction) toward the other end. It only has to be changed.

  The pneumatic tire includes a line connecting the reference point and the target position with the reference point of the cross-sectional shape as an axis, and a line passing through the reference point and orthogonal to the surface of the sidewall portion, like the ridge 212a and the ridge 212b. It is preferable that the angle formed by... Continuously changes from one end portion in the first direction toward the other end portion. As a result, the shape of the ridge can be periodically changed, light density can be more prominently generated, and the design can be improved. By making the design high, other portions can be made inconspicuous, and the unevenness of the sidewall portions can be made inconspicuous.

  Moreover, it is preferable that the angle formed between one end portion in the first direction and the other end portion of the ridge changes by one period. That is, it is preferable that the angle formed by a line passing through the reference line and perpendicular to the surface of the sidewall portion, the reference line, and the target position is one period at a predetermined period. Here, the waveform used as a reference for one cycle is a waveform whose value gradually changes although various waveforms can be used.

  The ridge may have a shape in which an angle formed between one end portion in the first direction and the other end portion changes more than one period. 9 and 10 are front views showing a schematic configuration of a ridge according to a modification. The ridge 212c shown in FIG. 9 has a midpoint of the top surface 220c as a reference line 230c, and the top surface 220c, the side surface 222c, and the end side 233c are changed according to the position in the extending direction with the reference line 230c as a reference. Yes. Here, the ridge 212c has a shape in which an angle formed by a line passing through the reference line 230c and perpendicular to the surface of the sidewall portion and a line connecting the reference line 230c and the target position changes two cycles. In the ridge 212d shown in FIG. 10, the midpoint of the end side 223d is a reference line 230d, and the position of the top surface 220d is changed according to the position in the extending direction. Further, the shape of the side surface 222d connecting the top surface 220d and the end side 223d changes corresponding to the change in the position of the top surface 220d. Here, the ridge 212d has a shape in which an angle formed by a line passing through the reference line 230d and perpendicular to the surface of the sidewall portion and the line connecting the reference line 230c and the target position changes two cycles. As shown in FIGS. 9 and 10, by changing the angle formed by two cycles or more, the shading of light can be made more complex and the design of the serration portion can be further improved.

  In addition, it is preferable that the ridge changes the angle formed by a line passing through the reference line and perpendicular to the surface of the sidewall portion and the reference line and the target position within a range of 10 degrees to 30 degrees. Thereby, the shading part can display the shadow of light more suitably, and the above effect can be obtained suitably.

  Next, the arrangement pattern of the ridges of the serration portion is not limited to this, and can be various shapes. In the pneumatic tire, it is only necessary to continuously change the cross-sectional shape of the ridge from one end portion in the first direction to the other end portion, and the arrangement of the ridge can be various. Hereinafter, the ridge arrangement position and arrangement pattern in the serration will be described with reference to FIGS.

  FIG. 11 is a side view of a pneumatic tire according to another embodiment. 12 is a perspective view showing a serration portion of the pneumatic tire shown in FIG. 13A is a cross-sectional view taken along the line Ab-Ab in FIG. 13B is a cross-sectional view taken along line Bb-Bb in FIG. 13C is a cross-sectional view taken along line Cb-Cb in FIG. Since the pneumatic tire 1a shown in FIGS. 11 to 13C is the same as the pneumatic tire 1 except for the shape of the serration portion 5a, the description thereof is omitted.

  The serration portion 5a has a large number of ridges 12a. The ridge 12a is a protrusion protruding in the tire width direction, and extends over the entire area in the tire radial direction. The serration portion 5a is arranged adjacent to the direction in which the ridge 12a intersects the extending direction, in this embodiment, the circumferential direction (Zθ direction).

  Similarly to the ridge 12, the ridge 12a has a top portion 20a and a side 22a. Further, a point where the side 22a is connected to the surface of the sidewall portion 3 is an end portion 23a. Since the ridge 12a also extends in the tire radial direction (first direction), the top portion 20a becomes the top surface 20a, the side 22a becomes the side 22a, and the end 23a becomes the end 23a.

  As shown in FIGS. 12 and 13A to 13C, the ridge 12a has a cross-sectional shape in a direction orthogonal to the extending direction that varies depending on the position in the extending direction. That is, the cross-sectional shape of the ridge 12a continuously changes from one end (inner ring 16) in the extending direction toward the other end (outer ring 18). Further, in the ridge 12a, the same phase line 40 having the same cross-sectional shape is inclined with respect to the tire circumferential direction. Specifically, the same phase line 40 has a shape that gradually moves from the inner side to the outer side in the tire radial direction when moving clockwise in the tire circumferential direction. That is, the serration portion 5a has a shape in which the ridge 12a at the position where the tire radial direction is the same and the adjacent ridge 12a are shifted so that the same phase portion of the ridge 12a adjacent in the clockwise direction is on the outer side in the tire radial direction. As a result, the serration portion 5a of the present embodiment changes in shape in cross section at one end (inner ring 16) in the extending direction depending on the position of the ridge 12a as shown in FIG. 13A. Similarly, in the serration portion 5a, the cross-sectional shape of the other end portion (outer ring 18) in the extending direction changes depending on the position of the ridge 12a as shown in FIG. 13B. In the serration portion 5a of the present embodiment, the shape of the ridge 12a cut by the same phase line is the same as shown in FIG. 13C.

  In the pneumatic tire 1a, the decorative region of the serration portion 5a is formed in a shape in which the position in the first direction where the angles formed by the ridges 12a are the same gradually changes between the adjacent ridges 12a in the second direction. The change in light shading can be clearly expressed by the tire circumferential direction and the tire radial direction, and the design can be improved.

  FIG. 14 is a side view of a pneumatic tire according to another embodiment. Since the pneumatic tire 1b shown in FIG. 14 is the same as the pneumatic tire 1 except for the shape of the serration portion 5b, the description thereof is omitted. The serration portion 5b has a shape in which the ridge 12b is inclined at a predetermined angle with respect to the tire radial direction and the tire circumferential direction. Specifically, in the ridge 12b, the direction of the dotted line 42 is the extending direction, and the angle formed with the tangent 44 in the tire circumferential direction at the contact point with the inner ring 16 is θa. That is, the angle between the ridge 12b and the tire radial direction is 90 degrees −θa. Like the pneumatic tire 1b, the ridge 12b may be arranged in a direction inclined by a predetermined angle with respect to the tire radial direction and the tire circumferential direction.

  FIG. 15 is a side view of a pneumatic tire according to another embodiment. Since the pneumatic tire 1c shown in FIG. 15 is the same as the pneumatic tire 1 except for the shape of the serration portion 5c, the description thereof is omitted. In the serration portion 5c, the ridge 12c has a curved shape. Specifically, the ridge 12 c has a shape along the curved imaginary line 46 and is disposed adjacent to the direction orthogonal to the imaginary line 46. Like the pneumatic tire 1c, the ridge 12c may have a shape other than a straight line. In FIG. 15, the curve is a curved line, but the ridge may be a combination of a straight line and a curved line, or may be a bent shape. The ridges are connected and extending in the extending direction (first direction).

  FIG. 16 is a side view of a pneumatic tire according to another embodiment. Since the pneumatic tire 1d shown in FIG. 16 is the same as the pneumatic tire 1 except for the shape of the serration portion 5d, the description thereof is omitted. In the serration portion 5d, the ridge 12d extends in the tire circumferential direction. The ridge 12d has a ring shape disposed on the entire circumference of the serration portion 5d in the tire circumferential direction. In this case, the ridge 12d has an arbitrary position (one position) as one end and the other end. In the serration portion 5d, a plurality of ridges 12d are adjacent to each other in the tire radial direction. Like the pneumatic tire 1d, the ridge 12d may have a shape in which the tire circumferential direction is the extending direction.

  FIG. 17 is a side view of a pneumatic tire according to another embodiment. 18 is an enlarged view in which the serration portion of the pneumatic tire shown in FIG. 17 is enlarged. Since the pneumatic tire 1e shown in FIG.17 and FIG.18 is the same as the pneumatic tire 1 except the shape of the serration part 5e, description is abbreviate | omitted. The serration unit 5 e has a plurality of ridges 52 and a plurality of ridges 54. The ridges 52 respectively extend in the tire radial direction and are arranged adjacent to each other in the tire circumferential direction in the same manner as the ridge 12. Similarly to the ridge 12d, the ridges 54 respectively extend in the tire circumferential direction and are arranged adjacent to each other in the tire radial direction. That is, in the serration portion 5e, the ridges 52 and the ridges 54 are arranged in a lattice pattern. Ridges may be arranged in a lattice like the pneumatic tire 1e. The lattice shape is not limited to the ridge in the tire radial direction and the ridge in the tire circumferential direction, and the lattice may be formed by ridges inclined with respect to the tire radial direction and the tire circumferential direction. Further, a lattice may be formed by overlapping ridges in three or more directions.

  FIG. 19 is a side view of a pneumatic tire according to another embodiment. Since the pneumatic tire 1f shown in FIG. 19 is the same as the pneumatic tire 1 except for the shape of the serration portion 5f, the description thereof is omitted. The serration portion 5 f has a plurality of decoration portions 62, and the decoration region is divided into a plurality in the tire circumferential direction by the plurality of decoration portions 62. The decorative part 62 and the decorative part 62 are separated by a boundary 64. The decoration part 62 has the plurality of ridges described above. The decorative portion 62 differs from the adjacent decorative portion 62 in the arrangement pattern of the ridges. For example, the phase of the fluctuation of the angle formed by the ridge changes at the boundary position, the extending direction of the ridge is different, or the fluctuation width of the angle formed by the ridge is different. The decorative region may be divided into a plurality of pieces like the pneumatic tire 1f. The dividing direction is not limited to the tire circumferential direction, and may be divided in the tire radial direction. Moreover, you may divide | segment at the boundary inclined by the predetermined angle with respect to the tire radial direction and the tire circumferential direction.

  In addition, as described in Japanese Patent Application Laid-Open No. 2011-37388 filed by the present applicant, the pneumatic tire extends in the radial direction and has a predetermined length of 0.8 mm or more and 3.0 mm or less. A ridge group formed by superimposing a first ridge group composed of a plurality of ridges arranged so as to be arranged at substantially equal intervals at a pitch and a second ridge group composed of ridges having substantially the same specifications as the first ridge group. The first ridge group and the second ridge group may be arranged by being shifted by a predetermined distance in the tire radial direction, and the predetermined distance may be 10 times or more and 25 times or less with respect to the pitch. Further, as disclosed in Japanese Patent Application Laid-Open No. 2012-56416, the ridge bundle includes a first portion in which a bundle of ridges extends from the inner side to the outer side in the tire radial direction from one side to the other side in the tire circumferential direction. Waves extending in the tire circumferential direction as a whole are formed by alternately arranging in the tire circumferential direction second ridges in which the bundle of ridges extends from the outer side in the tire radial direction toward the other side in the tire circumferential direction. It may be formed in a shape, and each ridge group may be configured to intersect with each other at a plurality of locations in the tire circumferential direction. In this case, each intersection where each ridge group intersects is such that the first part of one ridge group intersects the second part of the other ridge group, and the second part of one ridge group is the first part of the other ridge group. Configure to intersect. Thereby, the design property of a serration part can be improved more.

  In the pneumatic tire of the above-described embodiment, the design property can be enhanced in the entire region in the tire circumferential direction by setting the entire region of the serration portion as a decorative region in which the ridge is formed, but is not limited thereto. In the pneumatic tire, at least a part of the serration portion may be a decorative region. The pneumatic tire can improve a part of the design even when the decoration area of the serration portion is formed only in part.

  Next, with reference to FIGS. 20 to 24B, a tire molding die used in manufacturing the pneumatic tire described above will be described. FIG. 20 is a cross-sectional view in the meridian direction showing the tire molding die according to the present embodiment. FIG. 21 is a side view showing a ridge forming region of the tire molding die. 22A is a cross-sectional view taken along line Ac-Ac in FIG. 22B is a cross-sectional view taken along line Bc-Bc in FIG. 22C is a cross-sectional view taken along line Cc-Cc in FIG.

  The tire molding die 250 has a shape corresponding to the pneumatic tire manufactured by the inner peripheral surface. The tire molding die 250 has a shape that can be divided in the tire circumferential direction and the tire width direction. For example, the tire molding die 250 may be divided into a center mold corresponding to the tread portion and a side plate corresponding to the sidewall portion. In the tire molding die 250, convex portions 253a, 253b, 253c, 253d, and 253e for forming irregularities corresponding to tread patterns (main grooves, lug grooves, sipes, etc.) are formed in regions corresponding to the tread portions. Yes.

  In the tire molding die 250, a ridge formation region 260 is formed in a sidewall formation region that forms a sidewall portion. In the ridge formation region 260, a plurality of grooves 262 are formed. The groove 270 is a recess that forms the ridge 12 of the serration, and is arranged extending in the radial direction. The plurality of grooves 262 are disposed adjacent to each other in the circumferential direction.

  The groove 262 has a bottom surface 270 corresponding to the top surface 20 and a side surface 272 corresponding to the side surface 22 as shown in FIGS. 22A to 22C. A contact point between the side surface 272 and the surface of the sidewall forming region of the tire molding die 250 becomes an end side 273 corresponding to the end side 23. As shown in FIGS. 21 and 22A to 22C, the groove 262 has a cross-sectional shape in a direction orthogonal to the extending direction that is different depending on the position in the extending direction. That is, the cross-sectional shape of the groove 262 continuously changes from one end in the extending direction toward the other end. In the groove 262 of this embodiment, the cross-sectional shape of one end in the extending direction is such that the bottom surface 270 is inclined to one side (left side in FIG. 22A) as shown in FIG. 272 is shorter than the side 272 on the other side. In the groove 262, the cross-sectional shape of the other end in the extending direction is such that the bottom surface 270 is inclined to the other side (right side in FIG. 22B) as shown in FIG. 22B, and the other side 272 is one side. It becomes a shape shorter than the side 272 of. Further, the groove 262 has a symmetrical shape in cross section near the center in the extending direction as shown in FIG. 22C. As described above, the groove 262 has a shape in which the bottom surface 270 moves from one of the directions orthogonal to the extending direction to the other from one end of the extending direction toward the other end. The groove 262 has a shape in which the end side 273 is parallel to the radial direction. That is, in the groove 262, the end of the formation region in the circumferential direction (the direction orthogonal to the extending direction) is the same regardless of the position in the tire radial direction, and the position of the bottom surface 270 varies depending on the radial position. Thus, the cross-sectional shape continuously changes from one end portion in the radial direction toward the other end portion. The pneumatic tire 1 described above can be manufactured by manufacturing a pneumatic tire using the tire molding die 250 in which the groove 262 having the above shape is formed in the ridge forming region 260.

  Next, a method for forming the groove 262 will be described with reference to FIGS. 23A and 23B. FIG. 23A and FIG. 23B are explanatory views for explaining a method of manufacturing a tire molding die. FIG. 23A and FIG. 23B show a procedure for forming the groove 262 when the ridge 12 having a shape in which the center of the top surface 20 is a reference line is produced. In this case, as shown in FIGS. 23A and 23B, the processing tool 280 for cutting the ridge forming region 260 of the tire molding die 250 is pressed against the ridge forming region 260, and the processing tool 280 is extended in the extending direction (first direction). It is moved in the extending direction (first direction) while rotating in the orthogonal direction with the tip 290 as the base point. At this time, an angle θb formed by the center line 291 of the tip 290 of the processing tool 280 and the direction 292 orthogonal to the ridge forming region 260 is an angle formed by the ridge. Thereby, the groove | channel 262 corresponding to the ridge 12 of the shape where the center of the top surface 20 becomes a reference line can be formed.

  FIG. 24A and FIG. 24B are explanatory views for explaining a method of manufacturing a tire molding die. 24A and 24B show a procedure for forming the groove 262 in the case of manufacturing the ridge 212b having a shape in which the midpoint of the end portion becomes the reference line. In this case, as shown in FIGS. 24A and 24B, the processing tool 280 for cutting the ridge formation region 260 of the tire molding die 250 is pressed against the ridge formation region 260, and the surface of the ridge formation region 260 and the center of the processing tool 280 are While moving around the point where the two overlap each other, it is moved in the extending direction (first direction). At this time, an angle θb formed by the center line 291a of the tip 290a of the processing tool 280 and the direction 292a orthogonal to the ridge forming region 260 is an angle formed by the ridge. As a result, the groove 262 corresponding to the ridge 212b having a shape in which the midpoint of the end portion becomes the reference line can be formed.

  Next, the pneumatic tire will be described in more detail using examples. FIG. 25 is a perspective view illustrating a schematic configuration of the pneumatic tire of the first embodiment. FIG. 26 is a perspective view illustrating a schematic configuration of the serration unit according to the first embodiment. FIG. 27 is a perspective view illustrating a schematic configuration of the pneumatic tire of the second embodiment. FIG. 28 is a perspective view illustrating a schematic configuration of the serration unit according to the second embodiment. FIG. 29 is a perspective view illustrating a schematic configuration of the pneumatic tire of the third embodiment. FIG. 30 is a perspective view illustrating a schematic configuration of the serration unit according to the third embodiment. FIG. 31 is a perspective view illustrating a schematic configuration of a serration portion of a pneumatic tire of a comparative example. FIG. 32 is a perspective view showing a schematic configuration of a serration portion of a pneumatic tire of a comparative example. FIG. 33 is a perspective view illustrating a schematic configuration of a serration portion of the pneumatic tire of the example. FIG. 34 is a perspective view illustrating a schematic configuration of a serration portion of the pneumatic tire of the example.

  In this example, pneumatic tires having various ridge shapes were produced, and the appearance of the serration portion was evaluated. Specifically, the appearance of the shadow when the serration ridge reflected light was evaluated by sensory evaluation. In the sensory evaluation, the evaluation of Comparative Example 1 described later was set to 100, the appearance of the shadow was more suitable than Comparative Example 1, and the case where the design of the tire side face was improved was set to be larger than 100. The higher the value, the higher the design and the less noticeable the other parts.

  In the present embodiment, the range in which the angle θ formed by the line passing through the reference line and perpendicular to the surface of the sidewall portion and connecting the reference line and the target position is changed from −10 degrees to 10 degrees, from −20 degrees to 20 degrees. Degree, -30 degrees to 30 degrees. Also, in each case, pneumatic tires were produced in 12 combinations, assuming that the amount of deviation of the same phase position between adjacent ridges was 0, 10 mm, 20 mm, and 30 mm.

  In the present embodiment, as a comparative example, the angle θ formed by the line passing through the reference line and perpendicular to the surface of the sidewall portion and the reference line and the target position is not changed, that is, in FIG. 4 described above. A pneumatic tire having a serration portion of the shown pneumatic tire 101 was produced and evaluated. The evaluation results are shown in Tables 1 to 4 below.

  In addition, the serration portion 305 of the pneumatic tire 301 of Example 1 shown in FIGS. 25 and 26 is an angle formed by a line passing through the reference line and perpendicular to the surface of the sidewall portion and connecting the reference line and the target position. The range in which θ is changed is from −10 degrees to 10 degrees, and the amount of deviation is zero.

  In addition, the serration portion 305a of the pneumatic tire 301a of the second embodiment shown in FIGS. 27 and 28 is an angle formed by a line passing through the reference line and perpendicular to the surface of the sidewall portion, and a line connecting the reference line and the target position. The range in which θ is changed is from −20 degrees to 20 degrees, and the amount of deviation is zero.

  In addition, the serration portion 305b of the pneumatic tire 301b of the third embodiment shown in FIGS. 29 and 30 is an angle formed by a line passing through the reference line and perpendicular to the surface of the sidewall portion and connecting the reference line and the target position. The range in which θ is changed is from −30 degrees to 30 degrees, and the amount of deviation is zero.

  Further, the serration portion 405 of the pneumatic tire 401 of Comparative Example 1 shown in FIGS. 31 and 32 is an angle formed by a line passing through the reference line and perpendicular to the surface of the sidewall portion and connecting the reference line and the target position. The range in which θ is changed is 0 degree, and the amount of deviation is 0.

  As shown in Table 1 to Table 4, it can be seen that the design of the example is improved compared to the comparative example. As shown in FIGS. 25 to 32, the serration units 305, 305a, and 305b in the first to third embodiments have different shadows depending on the position, and the change jumps to the serration unit 405 in the first comparative example. You can see that it has a good design.

  Further, in this example, a pneumatic tire in which the serration portion was divided into a plurality of decoration portions was produced. FIG. 33 shows a part of the serration portion 505 of the pneumatic tire of the example. The serration unit 505 includes four decoration units 510a, 510b, 510c, and 510d. The decorative portions 510a, 510b, 510c, and 510d have a phase of an angle θ formed by a line passing through the reference line and perpendicular to the surface of the sidewall portion, and connecting the reference line and the target position between adjacent ridges. The shape gradually shifts in a direction perpendicular to the direction. The decorative portions 510a, 510b, 510c, and 510d have the same shape, and the phases of one boundary and the other boundary with the adjacent decorative portions are the same. The serration unit 505 shown in FIG. 33 has the same shading pattern of the four decoration parts 510a, 510b, 510c, and 510d, and the same inclined shadows are in the direction perpendicular to the extending direction, the decoration parts 510a, 510b, 510c, and 510d. It is formed every time.

  FIG. 34 shows a part of the serration portion 505a of the pneumatic tire of the example. The serration part 505a includes four decoration parts 520a, 520b, 520c, and 520d. In the decorative portions 520a, 520b, 520c, and 520d, the phase of the angle θ formed by the line that passes through the reference line and is perpendicular to the surface of the sidewall portion and the reference line and the target position extends between adjacent ridges. The shape gradually shifts in a direction perpendicular to the direction. In addition, the serration unit 505a has the opposite direction of the phase difference between the decoration parts 520a and 520c and the decoration parts 520b and 520d. The ridge adjacent to the boundary between the decorative portion 520a and the decorative portion 520b, the boundary between the decorative portion 520b and the decorative portion 520c, and the boundary between the decorative portion 520c and the decorative portion 520d passes through the reference line and is perpendicular to the surface of the sidewall portion. The angle θ formed by the line connecting the straight line, the reference line, and the target position is the same. In the serration part 505a shown in FIG. 34, the shadow patterns of the four decoration parts 520a, 520b, 520c, and 520d are alternately reversed, and a V-shaped shadow is formed by the two decoration parts. As shown in FIGS. 33 and 34, the shading pattern formed by adjusting the shift amount of the angle θ formed by the ridges forming the serration portions 505 and 505a and the shift direction can be changed to various patterns. I understand. As a result, the ridge has a shape that continuously changes from one end portion to the other end portion in the first direction, so that the serration portion can be shaded, and various shading patterns can be used. It turns out that it can be made into a shape, and according to this invention, it turns out that design property can be made high.

DESCRIPTION OF SYMBOLS 1 Pneumatic tire 2 Tread part 3 Side wall part 4 Bead part 5 Serration part 12 Ridge 14 Mark formation area 16 Inner ring 18 Outer ring

Claims (11)

A pneumatic tire comprising a tread portion, a sidewall portion, and a bead portion,
The sidewall portion has a decorative region in which a plurality of ridges that protrude from the outer surface and extend in the first direction are adjacent to each other in a second direction intersecting the first direction in a certain region in the tire radial direction. Have
The ridge has a cross-sectional shape in a direction perpendicular to the first direction continuously changing from one end portion to the other end portion in the first direction ,
An angle formed by a line connecting the reference point and the target position with the reference point of the cross-sectional shape as an axis and a line passing through the reference point and orthogonal to the surface of the sidewall portion is one of the first directions. Continuously changing from one end to the other end,
The position of the end of the cross-sectional shape in the second direction is constant regardless of the position in the first direction,
The pneumatic tire according to claim 1, wherein the reference point is a midpoint of an end portion of the cross-sectional shape in the second direction, and the target position is a top portion of the cross-sectional shape . A pneumatic tire comprising a tread portion, a sidewall portion, and a bead portion,
The sidewall portion has a decorative region in which a plurality of ridges that protrude from the outer surface and extend in the first direction are adjacent to each other in a second direction intersecting the first direction in a certain region in the tire radial direction. Have
The ridge has a cross-sectional shape in a direction perpendicular to the first direction continuously changing from one end portion to the other end portion in the first direction ,
An angle formed by a line connecting the reference point and the target position with the reference point of the cross-sectional shape as an axis and a line passing through the reference point and orthogonal to the surface of the sidewall portion is one of the first directions. Continuously changing from one end to the other end,
The ridge is a midpoint of a line connecting points of the same distance from the top on the side where the reference point is the top of the cross-sectional shape and the target position is connected to both ends of the top. A pneumatic tire characterized by that. The first direction is the tire radial direction,
The second direction, the pneumatic tire according to claim 1 or 2, characterized in that the tire circumferential direction. The pneumatic tire according to claim 1 or 2 , wherein the first direction is a direction having an inclination angle with respect to the tire radial direction of 90 degrees or less. The decorative region is any of claims 1-4, characterized in that position in the first direction in which the angle is the same of the ridge is gradually changed between the ridges adjacent to the second direction the pneumatic tire according to one paragraph or. The pneumatic tire according to any one of claims 1 to 5, wherein the ridge has an angle between 10 degrees and 30 degrees. The ridge, the air according to any one of claims 1 to 6, wherein the angle formed between the one end of the first direction to the other end, characterized in that the change for one period Enter tire. The ridges according to any one of claims 1 to 6, wherein the angle formed between the one end of the first direction to the other end, characterized in that the change more than one period Pneumatic tire. The said decoration area | region is provided with two or more decoration parts provided with the said several ridges whose said 1st direction is the same direction, The said decoration part differs in the said 1st direction from the said adjacent decoration part. The pneumatic tire as described in any one of 1 to 8 . The pneumatic tire according to any one of claims 1 to 9 , wherein the decoration region is disposed on the entire circumference in the tire circumferential direction. A tire molding die for molding the pneumatic tire according to any one of claims 1 to 10 ,
A sidewall portion forming portion for forming the sidewall portion on the inner peripheral surface;
The sidewall portion forming portion is disposed in a constant region in the tire radial direction and is adjacent to a second direction intersecting the first direction with a plurality of grooves that are concave on the inner peripheral surface and extend in the first direction. Having a ridge formation region,
The tire molding die according to claim 1, wherein a cross-sectional shape of the groove in a direction orthogonal to the first direction continuously changes from one end portion to the other end portion in the first direction.