• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
  • 同族专利
  • 引用文献
  • 法律状态
  • 优先权
    • 专利摘要:
    PNEUMATIC. A tire includes a tread portion provided with at least one main zigzag groove extending continuously in a circumferential direction of the tire with a plurality of zigzag corners. The main groove includes a groove bottom and a pair of groove edges. The groove bottom extends in a zigzag fashion in the circumferential direction of the tire with a first amplitude. The groove bottom has a periodically varying width so that the maximum width portion and the minimum width portion appear one at a time at the zigzag corners. Each of the groove edges extends in a zigzag fashion in the circumferential direction of the tire with a second amplitude, where the first amplitude is greater than the second amplitude.
    公开号:BR102015011121B1
    申请号:R102015011121-5
    申请日:2015-05-14
    公开日:2021-05-11
    发明作者:Kaori Tanaka；Atsushi Hibino
    申请人:Sumitomo Rubber Industries, Ltd.；
    IPC主号:
    专利说明:

    BACKGROUND OF THE INVENTION Field of Invention
    [0001] The present invention relates to tires and, in particular, relates to a tire having a main tread groove that can prevent the snag of stones. Description of Related Art
    [0002] Japanese Unexamined Patent Application Publication No. 2010-18125 discloses a tire which includes a tread portion having a circumferentially and continuously extending main groove. In order to prevent stone snagging in the main groove, the main groove includes a pair of groove walls, each of which includes an inner sharp radially sloping wall and an outer smooth radially sloping wall, wherein the radial height of the sloping wall smooth is varying periodically in a longitudinal direction of the main groove.
    [0003] Unfortunately, the groove wall configuration described above is not sufficient to prevent the tires from picking up stones for use over gravel and the like. Invention Summary
    [0004] In view of the above problems in the conventional art, the present invention has an object to provide a tire having a main tread groove that can prevent the snag of stones.
    [0005] According to an aspect of the invention, a tire includes a tread portion provided with at least one zigzag main groove, continuously extending in a circumferential direction of the tire with a plurality of zigzag corners. The main groove includes a groove bottom and a pair of groove edges. The groove bottom extends in a zigzag fashion in the circumferential direction of the tire in a first amplitude. The groove bottom has a periodically varying width so that a maximum width portion and a minimum width portion appear, in turn, at the zigzag corners. Each of the groove edges extends in a zigzag fashion in the circumferential direction of the tire with a second amplitude, where the first amplitude is greater than the second amplitude.
    [0006] In another aspect of the present invention, the main groove may include a pair of groove walls, each of which extends from the bottom of the groove to one of the groove edges. Each of the groove walls can include an outer corner and an inner corner. A slope angle 2 of the outer corner with respect to a normal tread line at the minimum width portion of the groove bottom may be greater than a slope angle 1 of the outer corner with respect to the normal tread line at the maximum width portion of the groove bottom.
    [0007] In another aspect of the present invention, the main groove comprises a pair of groove walls each of which extends from the groove bottom to one of the groove edges. Each of the groove walls includes an outer corner and an inner corner. An incline angle 3 of the inner corner with respect to a normal tread line in the maximum width portion of the groove bottom may be equal to or less than an incline angle 4 of the inner corner with respect to the normal tread line. running in the minimum width portion of the groove bottom.
    [0008] In another aspect of the present invention, the main groove may extend close to a tread edge. The zigzag corners comprise an axially inner protruding corner and an axially outer protruding corner and the maximum width portion of the groove bottom may appear at the axially inner protruding corner.
    [0009] In another aspect of the present invention, the main groove may be provided with a protrusion at the bottom of the groove. The protrusion may be formed at the maximum width portion of the groove floor, and the protrusion may not be formed at the minimum width portion of the groove floor.
    [0010] In another aspect of the present invention, the protrusion may have a width smaller than that of the maximum width portion of the groove bottom.
    [0011] In another aspect of the present invention, the protrusion may have a width in a range of 20% to 40% of a width of the maximum width portion of the groove bottom.
    [0012] In another aspect of the present invention, the protrusion may have a radial height in a range of 5% to 25% of a main groove depth.
    [0013] In another aspect of the present invention, the main slot may include a pair of slot walls each of which extends from the slot bottom to one of the slot edges. Each of the groove walls comprises an outer corner. A portion radially outward from the outer corner can be provided with a beveled portion.
    [0014] In another aspect of the present invention, the beveled portion may have an inclined surface extending between a ground contacting surface of the tread portion and a pair of two wall planes forming the outer corner.
    [0015] In another aspect of the present invention, the chamfered portion is located at an axial distance of 0.5 to 3.0 mm from an imaginary point where a ground contact surface of the tread portion and a pair of two wall planes, forming the outer corner, intersect, imaginatively.
    [0016] In another aspect of the present invention, the beveled portion may have a radial length in a range of 25% to 60% of a maximum depth of the main groove.
    [0017] In another aspect of the present invention, each of the groove walls may include an inner corner and an outer corner rake angle with respect to a normal tread line is greater than an inner corner rake angle with respect to the normal tread line at the respective zigzag corners. Brief Description of Drawings
    [0018] Figure 1 is a design view of a tread portion of a tire according to a first embodiment of the present invention.
    [0019] Figure 2A is an enlarged view of a groove bottom of a main cam groove shown in Figure 1.
    [0020] Figure 2B is an enlarged view of groove edges of the main cam groove shown in Figure 1;
    [0021] Figure 3 is an enlarged view of the main cam groove shown in Figure 1;
    [0022] Figure 4 is a cross-sectional view taken along lines X-X of Figure 1;
    [0023] Figure 5 is a cross-sectional view taken along the Y-Y lines of Figure 1;
    [0024] Figure 6 is a design view of a tread portion of a reference tire;
    [0025] Figure 7 is a design view of a tread portion of another reference tire;
    [0026] Figure 8 is a design view of a tread portion of a tire according to a second embodiment of the present invention;
    [0027] Figure 9 is an enlarged view of the main cam slot shown in Figure 8.
    [0028] Figure 10 is a cross-sectional view taken along lines X-X of figure 8.
    [0029] Figure 11 is a cross-sectional view taken along the Y-Y lines of Figure 8;
    [0030] Figure 12 is a partial perspective view of the main boss groove shown in Figure 8. Description of Achievements
    [0031] An embodiment of the present invention will be explained below with reference to the accompanying drawings. It should be noted that similar elements are denoted by the same reference numbers throughout the exhibition. [First Implementation]
    [0032] Figure 1 illustrates a tread portion 2 of a tire 1, according to the first embodiment of the present invention. As shown in figure 1, tire 1 can be embodied as a heavy-duty tire for trucks or buses.
    [0033] The tread portion 2 is provided with at least one main groove which extends continuously in a circumferential direction of the tyre. In this embodiment, the at least one groove includes a pair of main shoulder grooves 3, each of which is disposed close to a tread edge Te on either side of the tire equator C and a central main groove 4, disposed at the tire equator C. For the at least one main groove, it should be noted that the present invention is not particularly limited to the configuration shown in figure 1.
    [0034] On each side of the tire equator C, the tread edge Te is defined as an axially outermost edge of the tread portion 2. In the case where the axially outermost edge of the tread portion 2 is not clearly identified in appearance, tread edge Te refers to an axially outer edge of the ground contact portion of tread portion 2, which occurs under a normally inflated loaded condition, when the tire camber angle is zero. The normally inflated loaded condition is such that tire 1 is mounted on a standard wheel rim with a standard pressure and loaded with a standard tire load.
    [0035] The standard wheel rim is an officially approved or recommended wheel rim for the tire by standard organizations, where the standard wheel rim is the "standard rim" specified in JATMA, the "Measurement Rim" in ETRTO and the “Drawing Ring”, in TRA, or similar, for example.
    [0036] The standard pressure is an approved or officially recommended standard pressure for the tire by standards organizations, where the standard pressure is the "maximum air pressure" in JATMA the "Inflation pressure" in ETRTO , and the maximum pressure given in the table of “Tyre Load Limits at Various Cold Inflation Pressures”, in TRA or similar, for example.
    [0037] The standard tire load is an officially approved or recommended tire load for the tire by standards organizations, where the standard load is the "Maximum Load Capacity", in JATMA, the "Load Capacity" , in ETRTO and the maximum value given in the table mentioned above, in TRA, or similar.
    [0038] In the present application, including report and claims, various dimensions, positions and the like of the tire refer to those under a normally inflated unloaded condition of the tire, unless otherwise noted. The inflated unloaded condition is normally such that tire 1 is mounted on the standard wheel rim with standard pressure, but not loaded with tire load. The tread width TW is defined as the width measured under the normally inflated unloaded condition, as the actual distance between the tread edges Te and Te.
    [0039] The main cam groove 3 extends in a zigzag fashion in the circumferential direction of the tire with a plurality of zigzag corners 7. Namely, the main cam groove 3 includes a first inclined element 3A and a second inclined element 3B having an inclination opposite to that of the first inclined element 3A, which are alternately arranged in the circumferential direction of the tire to form the zigzag corner 7 therebetween. Cam 3 main groove includes an axial groove edge component, which can provide stable drive by generating traction in rough terrain such as an unpaved path.
    [0040] The main shoulder groove 3 includes a groove bottom 8, a pair of groove edges 9 on a ground-contacting surface 2a of the tread portion 2 and a pair of groove walls 10, each of which extends from the bottom of the groove 8 to one of the edges of the groove 9.
    [0041] The groove bottom 8 is the radially innermost surface, which has a maximum depth D1, shown in Figure 4 and which extends in the axial direction of the tire, parallel to the ground contact surface 2a of the tread portion. run-in 2. When the radially innermost surface is connected to the groove wall 10 through a rounded chamfer, the groove bottom 8 is defined as a region between the points B located on the groove surface at a depth of 90% of the maximum depth D1.
    [0042] Figure 2A illustrates an enlarged view of the bottom of groove 8 of the main right side shoulder groove 3 of Figure 1. As shown in Figure 2A, the bottom of groove 8 includes a first sloping bottom portion 8A and a second sloping bottom portion 8B having an opposite slope to the first sloping bottom portion 8A. In figure 2A, the first sloping bottom portion 8A has an axial width W, which is gradually increasing upwards to have a trapezoidal shape. In figure 2A, the second sloping bottom portion 8B has an axial width W, which is gradually decreasing upwards to have a trapezoidal shape. The first sloping bottom portion 8A and the second sloping bottom portion 8B are alternately disposed in the circumferential direction of the tire so that the groove bottom 8 zigzags extends in the circumferential direction of the tire with a first amplitude V1 . Furthermore, the groove bottom 8 has the width W varying periodically, so that a maximum width portion 12 and a minimum width portion 13 appear, in turn, at the zigzag corners. The zigzag shape of the groove bottom 8 is not particularly limited to the above structure, but can be employed in an undulating manner (smooth zigzag).
    [0043] Since the maximum width portion 12 can provide a low lift force for a stone trapped in the main shoulder groove 3, the maximum width portion 12 can easily release the stone from it, thus preventing snag. stones. When a stone is stuck in the minimum width portion 13, the stone may gradually move towards the maximum width portion 12, where less frictional force will act on the stone due to the opening deformation - closing of the main groove of bounce 3, during shift and then the stone would be released.
    [0044] Figure 2B illustrates an enlarged view of the groove edges 9 of the main shoulder groove 3 on the right side of Figure 1. As shown in Figure 2B, each of the groove edges 9 extends zigzag in the circumferential direction. tire with a second amplitude V2. The zigzag shape of the groove edges 9 is synchronized with that of the groove bottom 8. As shown in Figures 2A and 2B, the first amplitude V1 of the groove bottom 8 is greater than the second amplitude V2 of the respective groove edges 9 As a result, the main shoulder groove 3 may have the pair of groove walls 10, each having an angle of inclination with respect to a normal line of tread, wherein the angle of inclination varies in the circumferential direction of the tire. . Thereby, the main shoulder groove 3 can provide elastic restoring force whose direction varies in the circumferential direction of the tire to push the stone trapped between the groove walls 10. The stone trapped in the main shoulder groove 3 can easily move in the circumferential direction of the tire and then it would be released from the main shoulder groove 3.
    [0045] Furthermore, since the second amplitude V2 of the groove edge 9 is smaller than the first amplitude V1 of the groove bottom 8, the stiffness of the ground contact surface 2a of the tread portion 2 in around the main spline 3 groove can be accentuated, thus optimizing the wear resistance of the tyre. Here, the first amplitude V1 of the groove bottom 8 is defined using a centerline 8c of the groove bottom 8 and the second amplitude V2 of the groove edge 9 is defined using a centerline 9c of the area between groove edges 9 and 9 .
    [0046] Although the main cam groove 3 tends to grip a stone due to the lateral force when cornering, the main cam groove 3, according to the present invention, can efficiently prevent the snag of the stone even in this situation. of curves.
    [0047] In order to further improve the stone snagging effect of the main shoulder groove 3, the second amplitude V2 of the groove edges 9 is preferably in a range of 20% to 50% of the first amplitude V1 from the bottom of the slot 8.
    [0048] In order to further improve the stone gripping effect of the main shoulder groove 3, an angle 1 of the centerline 8c of the groove bottom 8 is preferably in a range of 10 to 40 degrees with respect to circumferential direction of the tire. The difference (1 - θ2) between an angle θ1 of the centerline 8c of the groove bottom 8 and an angle 2 of the centerline 9c between the groove edges 9 with respect to the circumferential direction of the tire is preferably in a range of 10 to 30 degrees.
    [0049] As shown in Figure 1, the zigzag corners 7 comprise an axially inwardly projecting corner 11A and an axially outwardly projecting corner 11B. The maximum width portion 12 of the groove bottom 8 appears in the axially inwardly projecting corner 11A. The maximum width portion 12 can provide a larger groove volume than the minimum width portion 13, thus decreasing the stiffness of the tread around it. In order to further improve the wear resistance of the tire, the maximum width portion 12 may preferably appear in the axially inwardly projecting corner 11A, where a relatively low lateral force will be acted upon during cornering as compared with the corner projecting axially outward 11B.
    [0050] On the other hand, the minimum width portion 13 of the groove bottom 8 appears in the axially outwardly projecting corner 11B. Thereby, the stiffness of the tread portion 2 around the main shoulder groove 3 can be equalized in the circumferential direction of the tyre, thus improving the wear resistance of the tyre.
    [0051] In order to further improve the above effects, the minimum width portion 13 preferably has a width Wb in a range of 50% to 80% of a width Wa of the maximum width portion 12, as shown in Figure 2A.
    [0052] Figure 3 illustrates an enlarged view of the main boss groove 3 on the right side of Figure 1. As shown in Figure 3, the groove walls 10 comprise an outer groove wall 10a, disposed on the side of the band edge. tread Te, and an inner groove wall 10b, disposed on the side of the tire equator C.
    [0053] Each of the groove walls 10a and 10b includes an outer corner (projected corner) 15 that protrudes outwardly and an inner corner (crumpled corner) 16 that is crumpled inward.
    [0054] At the axially inwardly projecting corner 11A where the maximum width portion 12 appears, the outer groove wall 10a is formed at the outer corner 15a and the inner groove wall 10b is formed at the inner corner 16a. At the axially outwardly projecting corner 11B, where the minimum width portion 13 appears, the inner groove wall 10b is formed at the outer corner 15b, and the outer groove wall 10a is formed at the inner corner 16b.
    [0055] Figure 4 illustrates a cross-sectional view of the maximum width portion 12 taken along the lines XX of Figure 1, and Figure 5 illustrates a cross-sectional view of the minimum width portion 13, taken along the lines YY of figure 1. As shown in figures 4 and 5, an inclination angle 2 of the outer corner 15b with respect to a normal tread line n in the minimum width portion 13 of the groove bottom 8 is greater than an angle of inclination 1 of the outer corner 15a with respect to the normal line of tread n in the maximum width portion 12 of the groove bottom 8. The reaction force R2 of the outer corner 15b against a stone trapped in the minimum width portion 13 can guide radially outward, compared to the force R1 of the outer corner 15a reacting against a stone trapped in the maximum width portion 12. Thereby, the minimum width portion 13 can push to move the stone in a radially outward direction, thereby, preventing the grab tion of stones.
    [0056] When the slant angle 2 of the outer corner 15b at the minimum width portion 13 is excessively large, compared to the slant angle 1 of the outer corner 15a at the maximum width portion 12, the stiffness difference between the width portion maximum 12 and the minimum width portion 13 tends to be larger, thus decreasing wear resistance. In view of the above, the difference (2 - α1) of the inclination angles α2 and α1 is preferably in a range of 1.5 to 6.0 degrees.
    [0057] In order to further improve the above effects, the inclination angle 1 of the outer corner 15a at the maximum width portion 12 is preferably in a range of not less than 8 degrees, more preferably not less than than 11 degrees, but preferably no more than 20 degrees, more preferably no more than 16 degrees. Similarly, the inclination angle 2 of the outer corner 15b at the minimum width portion 13 is preferably in a range of not less than 14 degrees, more preferably not less than 15 degrees, but preferably not more than 22 degrees, more preferably no more than 19 degrees.
    [0058] A slant angle 3 of the inner corner 16a with respect to the normal line of tread n in the maximum width portion 12 of the groove bottom 8 is equal to or less than a slant angle 4 of the inner corner 16b with respect to the normal tread line n at the minimum width portion 13 of the groove bottom 8. At the minimum width portion 13, which tends to grip a stone due to its small width W, the reaction force R4 of the inner corner 16b against the stone can orient radially outward, compared to the reaction force R3 of the inner corner 16a in the maximum width portion 12. Thereby, the stone trapped in the minimum width portion 13 can be easily moved and then released.
    [0059] When the inclination angle 3 of the inner corner 16a at the maximum width portion 12 is excessively small with respect to the inclination angle 4 of the inner corner 16b at the minimum width portion 13, the tread stiffness difference between the maximum width portion 12 and minimum width portion 13 tends to be larger, thus decreasing wear resistance. In view of the above, the difference («4 - «3) of the tilt angles 4 and 3 is preferably in a range of 1.0 to 4.0 degrees.
    [0060] In order to further improve the above effects, the elaboration apparatus 3 of the inner corner 16a at the maximum width portion 12 is preferably in the range of not less than 2.0 degrees, more preferably not less than 2.5 degrees, but preferably not more than 7.0 degrees, more preferably not more than 6.0 degrees. In the same view, the inclination angle «4 of the inner corner 16b at the minimum width portion 13 is preferably in a range of not less than 2.5 degrees, more preferably not less than 3.0 degree, but preferably not more than 10.0 degrees, more preferably not more than 7.0 degrees.
    The main boss groove 3 is provided with a protrusion 20 in the bottom of groove 8. When a stone is trapped above the protrusion 20 in the main boss groove 3, the protrusion 20 is elastically compressed by the stone. The resilience of the protrusion 20 can push the stone away from the main shoulder groove 3.
    [0062] In this embodiment, the protrusion 20 is formed in the maximum width portion 12 of the groove bottom 8. The tread stiffness around the maximum width portion 12 is relatively less than that around the minimum width portion 13. As a result, the protrusion 20 can accentuate a portion around the maximum width portion 12 so as to equalize the stiffness of the tread on the circumferential tire.
    [0063] Referring again to Figure 2A, the protrusion 20 extends along with the centerline 8c of the groove bottom 8. In this embodiment, the protrusion 20 curves in a V-shaped mode in the maximum width portion 12. Such protrusion 20 can accentuate the rigidity of the groove bottom 8 so as to prevent deformation so that the groove walls 10 approach each other. This makes it possible to further improve boulder grabbing.
    [0064] Preferably, the protrusion 20 has a width W1 less than that of the maximum width portion 12 of the groove bottom 8, so as to have flexibility in that it can elastically deform easily, to create force of enough resiliency to push the stone out. When the width W1 of the protrusion 20 is too small, the rigidity of the protrusion 20 can be decreased. This can cause the protrusion 20 to fragment or generate less resilience to push the stone out of the groove. Preferably, the protrusion 20 has the width W1 in a range of not less than 20%, more preferably not less than 25%, but preferably not more than 40%, more preferably not more than 35% of the width Wa of the maximum width 12 portion of the groove bottom 8.
    [0065] In order to further improve the effect described above, the protrusion 20 has a radial height H1, as shown in Figure 4, in a range of not less than 5%, more preferably not less than 10%, but preferably not more than 25%, more preferably not more than 20% of the maximum depth D1 of the main shoulder groove 3. In the same view, the protrusion 20 has a circumferential length L1 in a range of 20% to 40% of a circumferential pitch length P1 of the groove bottom 8 as shown in Figure 2A.
    [0066] In this embodiment, the protrusion 20 is not formed in the minimum width portion 13 of the groove bottom 8. This makes it possible to equalize the stiffness of the tread portion 2 around the main shoulder groove 3 in the circumferential direction of the tire. , thus further improving the wear resistance of the tread portion 2.
    [0067] As shown in Figure 1, the main shoulder groove 3 preferably has the axial width Ws in a range of 2% to 8% of the tread width TW in order to further improve the grip resistance of stones, as well as the rigidity of the tread. Preferably, the main shoulder groove 3 has a maximum depth D1 of 15 to 25 mm.
    [0068] In this embodiment, the central main groove 4 extends zigzag in the circumferential direction of the tire. The central main groove 4 includes a groove bottom 4a, having a constant width Wd in the circumferential direction of the tyre. Furthermore, the groove bottom 4a and the groove edges 4b of the central main groove 4 have the same zigzag amplitude. Preferably, the central main groove 4 has a width Wc in a range of 2% to 8% of the tread width TW, and a maximum depth of 15 to 25 mm, for example. [Second Achievement]
    [0069] Next, the second embodiment of the present invention will be described below with reference to the accompanying drawings. Figure 8 illustrates a design view of the tread portion 2 of the tire according to the second embodiment of the present invention. Figure 9 illustrates an enlarged view of the main cam groove 3 on the right side of Figure 8. As shown in Figures 8 and 9, the main cam groove 3 includes the pair of groove walls 10, each of which includes the corner. outer 15 and inner corner 16 at zigzag corners 7.
    [0070] Generally speaking, the outer corner 15, particularly the radially outermost portion of the outer corner 15 located near the ground contact surface 2a of the tread portion 2 tends to be fragmented during displacement due to its Low rigidity. Such fragmentation can cause uneven wear on outer corner 15. In the second embodiment of the present invention, a radially outward portion of outer corner 15 is provided with a beveled portion 22 to prevent such uneven wear. The chamfered portion 22 can prevent a fragmentation of the outer corner 15 into its radially outermost portion, so that uneven wear is not caused. Furthermore, the chamfered portion 22 makes it possible to expand the groove width of the main shoulder groove 3 in the ground-contacting surface of the tread portion 2, thus releasing a stone trapped in the minimum width portion 13 or in the portion. of maximum width 12, easily.
    [0071] In order to further improve the effects described above, the beveled portion 22 is preferably formed on an inclined triangular surface or plane extending between the ground contact surface 2a of the tread portion 2 and a pair of two wall planes forming the outer corner 15.
    [0072] Figure 10 illustrates a cross-sectional view taken along lines XX of figure 8. Figure 10 corresponds to a cross-sectional view of the main shoulder groove 3 in the maximum width portion 12. Figure 11 illustrates a a cross-sectional view taken along lines YY of figure 8. Figure 11 is a cross-sectional view of the main groove 3 in the minimum width portion 13. Figure 12 is a partial perspective view of the main slot of shoulder 3 of figure 8. As shown in figures 10 to 12, the chamfered portion 22 is preferably located at an axial distance W2 of 0.5 to 3.0 mm from the imaginary point G where the contact surface with the ground 2a of the tread portion 2 and a pair of two wall planes 10f forming the outer corner 15 imaginary intersect. Here, the reference sign “S1” denotes a ridge formed by two wall planes 10f, forming the outer corner 15. This specific structure of the bevel portion 22 can further improve the above effects. In the same view, the chamfered portion 22 preferably has a radial length D2 in a range of 25% to 60% of the maximum depth D1 of the main shoulder groove 3.
    [0073] As shown in Figure 8, the central main groove 4 includes the groove bottom 4a, the pair of groove walls 4c and a pair of groove edges 4b. In this embodiment, the respective outer corners 4d of the groove walls 4c are provided with a chamfered portion 23, having substantially the same structure as the chamfered portion 22. As a result, the central main groove 4 can also prevent not only the grasping of stones, but also irregular wear.
    [0074] In this embodiment, the tread portion 2 is further provided with a plurality of narrow grooves extending in a zigzag fashion in the circumferential direction of the tyre, for example. Furthermore, the tread portion 2 is provided with a plurality of lateral grooves which extend between the central main groove 4 and the main cam groove 3 or between the main cam groove 3 and the tread edge Te in order to improve traction and drainage performance of the tire.
    [0075] Although particularly preferable embodiments of the tire according to the present invention have been described in detail, the present invention is not limited to the illustrated embodiments, but can be modified and realized in various aspects. [First Example]
    [0076] Tires having a size of 11R22.5 and a basic tread pattern, shown in figure 1, were manufactured to the specifications in Table 1 and tested. The most common tire specifications and testing procedures are as follows.
    [0077] Specification:
    [0078] Tread width TW: 218 mm
    [0079] Widths of the main boss and center slots: 13.2 mm
    [0080] Depths of the main boss and center grooves: 21.6 mm
    [0081] As for the inclination angles 1 to 4 of the tires of Ref. 1 Ref. 2, they were measured in the same positions as the inclination angles 1 to 4 of the tires in the Examples. Stone snag resistance test:
    [0082] Each test tire was mounted on a 22.5 x 8.25 rim and inflated to an internal pressure of 830 kPa and installed on all wheels of a 2-DD wheel type bus. Then a test driver drove the bus on a gravel road for 30,000 km. Then, the number of stones stuck in the main grooves of the rear wheels shoulders was counted. The results are shown in Table 1 using an index based on Example 1 being 100. The higher the value, the greater the performance. Irregular wear resistance test:
    [0083] After the stone grip test, the irregular wear state of the front wheels such as gear wear, river wear, rail wear and the like were checked through the eyes of the test driver. The results are shown in Table 1, using a score of 1 to 5 based on the most excellent tire being 5. The higher the value, the greater the performance.
    [0084] The test results are shown in table 1. From the test results, it was confirmed that the example tires had excellent stone grip resistance and uneven wear resistance when compared to the reference tires. In addition, another test was conducted using tires having a different tire size, in which the test results were confirmed. [Table 1] (1/3)
    [Table 1] (2/3)
    [Table 1] (3/3)
    [Second Example]
    [0085] Tires having a size of 11R22.5 and a basic tread pattern shown in figure 8, were manufactured based on the specifications in Table 2 and tested in the same manner as described above. The Ref. 3 tire was not provided with the beveled portion.
    [0086] The test results are shown in Table 2. From the test results, it was confirmed that the tires in the examples had excellent stone grip resistance and irregular wear resistance compared to the reference tyre. [Table 2] (1/4)
    [Table 2] (2/4)
    [Table 2] (3/4)
    [Table 2] (4/4)
    权利要求:
    Claims (13)
    [0001]
    1. A tire (1) comprising: a tread portion (2) provided with at least one main zigzag groove (3) extending continuously in a circumferential direction of the tire with a plurality of zigzag corners (7); the main groove (3) comprising a groove bottom (8) and a pair of groove edges (9); the groove bottom (8) extending in a zigzag fashion in the circumferential direction of the tire with a first amplitude (V1), the groove bottom (8) having a width (W) varying periodically so that a portion of maximum width (12) and a portion of minimum width (13) appear at a time at the zigzag corners (7); and each of the groove edges (9) extending in a zigzag fashion in the circumferential direction of the tire with a second amplitude (V2), wherein the first amplitude is greater than the second amplitude (V2), characterized in that the main groove (3) is provided with a protrusion (20) at the bottom of the groove (8), and the protrusion (20) is formed on the maximum width portion (12) of the bottom of the groove (8).
    [0002]
    2. Pneumatic (1) according to claim 1, characterized in that the main groove (3) comprises a pair of groove walls (10) each of which extends from the groove bottom (8) for one of the groove edges (9), each of the groove walls (10) comprises an outer corner (15) and an inner corner (16), and an inclination angle α2 of the outer corner (15) with respect to a normal tread line in the minimum width portion (13) of the groove bottom (8) is greater than an inclination angle α1 of the outer corner (15) with respect to the tread normal line in the maximum width portion ( 12) of the groove bottom (8).
    [0003]
    3. Tire (1) according to claim 1, characterized in that the main groove (3) comprises a pair of groove walls (10) each of which extends from the groove bottom (8) for one of the groove edges (9), each of the groove walls (10) comprises an outer corner (15) and an inner corner (16), and an inclination angle α3 of the inner corner (16) with respect to a normal tread line in the maximum width portion (12) of the groove bottom (8) is equal to or less than the inclination angle α4 of the inner corner (16) with respect to the normal tread line in the width portion minimum (13) of the bottom of the groove (8).
    [0004]
    4. Tire (1) according to claim 1, characterized in that the main groove (3) extends close to a tread edge (Te), the zigzag corners (7) comprise a protruding corner axially inner (11A) and an axially outer protruding corner (11B), and the maximum width portion (12) of the groove bottom (8) appears at the axially inner protruding corner (11A).
    [0005]
    5. Tire (1) according to claim 1, characterized in that the protrusion (20) is not formed in the minimum width portion (13) of the groove bottom (8).
    [0006]
    6. Tire (1) according to claim 5, characterized in that the protrusion (20) has a width (W1) smaller than that (Wa) of the maximum width portion (12) of the groove bottom (8 ).
    [0007]
    7. Tire (1) according to claim 5, characterized in that the protrusion (20) has a width (W1) in the range of 20% to 40% of a width (Wa) of the maximum width portion ( 12) from the bottom of the groove (8).
    [0008]
    8. Pneumatic (1) according to claim 5, characterized in that the protrusion (20) has a radial height (H1) in a range of 5% to 25% of a maximum depth (D1) of the main groove (3).
    [0009]
    9. Pneumatic (1) according to claim 1, characterized in that the main groove (3) comprises a pair of groove walls (10) each of which extends from the groove bottom (8) to one of the groove edges (9), each of the groove walls (10) comprises an outer corner (15), and a portion extending radially outward from the outer corner (15) is provided with a bevelled portion (22 ).
    [0010]
    10. Pneumatic (1) according to claim 9, characterized in that the beveled portion (22) has an inclined surface that spreads between a ground contact surface (2a) of the tread portion ( 2) and a pair of two flat walls (10f) forming the outer corner (15).
    [0011]
    11. Pneumatic (1) according to claim 9, characterized in that the beveled portion (22) is located at an axial distance (W2) of 0.5 to 3.0 mm from an imaginary point ( G) where a ground contact surface (2a) of the tread portion (2) and a pair of two flat walls (10f) forming the outer corner (15) imaginary cross.
    [0012]
    12. Pneumatic (1) according to claim 9, characterized in that the bevel portion (22) has a radial length (D2) in a range of 25% to 60% of a maximum depth (D1) of the groove main (3).
    [0013]
    13. Pneumatic (1) according to claim 9, characterized in that each of the groove walls (10) comprises an inner corner (16), and an inclination angle (α2) of the outer corner (16) with respect to a normal tread line is greater than an inclination angle (α4) of the inner corner (16) with respect to the normal tread line at the respective zigzag corners (7).
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    CN105313602A|2016-02-10|
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    CN108883672B|2016-03-28|2020-09-18|株式会社普利司通|Tyre for vehicle wheels|
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    JP2019104410A|2017-12-13|2019-06-27|Ｔｏｙｏ Ｔｉｒｅ株式会社|Pneumatic tire|
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    CN111323245A|2020-03-13|2020-06-23|安徽德技汽车检测中心有限公司|Test method for detecting stones entrained in running process of tire|
    法律状态:
    2016-06-14| B03A| Publication of a patent application or of a certificate of addition of invention [chapter 3.1 patent gazette]|
    2018-10-30| B06F| Objections, documents and/or translations needed after an examination request according [chapter 6.6 patent gazette]|
    2019-12-31| B06U| Preliminary requirement: requests with searches performed by other patent offices: procedure suspended [chapter 6.21 patent gazette]|
    2020-11-10| B06A| Notification to applicant to reply to the report for non-patentability or inadequacy of the application [chapter 6.1 patent gazette]|
    2021-03-09| B09A| Decision: intention to grant [chapter 9.1 patent gazette]|
    2021-05-11| B16A| Patent or certificate of addition of invention granted|Free format text: PRAZO DE VALIDADE: 20 (VINTE) ANOS CONTADOS A PARTIR DE 14/05/2015, OBSERVADAS AS CONDICOES LEGAIS. |
    优先权:
    申请号 | 申请日 | 专利标题
    JP2014-111630|2014-05-29|
    JP2014111630|2014-05-29|
    JP2014197356A|JP6023769B2|2014-09-26|2014-09-26|Pneumatic tire|
    JP2014-197356|2014-09-26|
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