Construction vehicle tires

Abstract

To provide a tire for a construction vehicle, the tire including a tread and enabling the heat dissipation efficiency of the overall of the tread to be further improved.SOLUTION: In a tread 20 of a tire 10 for a construction vehicle, the following grooves are formed: width-direction narrow grooves 100 extending in a tire-width direction TW; a center circumferential groove 30 communicated with one-side ends in the width direction, of the narrow grooves 100, extending in a tire circumferential direction TC and formed at a position including a tire equator line CL; outer circumferential grooves 40 and 50 communicated with the other ends of the narrow grooves 100, formed on the tire width-direction outside TW of the narrow grooves 100 and extending in the tire circumferential direction TC; and a plurality of notched grooves 110 and 210 in a slope shape respectively communicated with the width-direction narrow grooves 100. In the tire width direction TW, intermediate circumferential grooves 60 extending in the tire circumferential direction TC and crossing the width direction-narrow grooves 100 are formed between the plurality of notched grooves 110 and 210.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a tire for a construction vehicle having a tread in which a plurality of slope-shaped notched grooves are formed in widthwise narrow grooves, and intermediate circumferential grooves are formed between the notched grooves. [Background technology]

[0002] A construction vehicle tire having a tread in which sloped cutout grooves are formed is known (for example, see Patent Document 1). In this construction vehicle tire, the sloped cutout grooves formed in the tread are said to be able to efficiently cool the entire tread while suppressing the impact on, for example, wear resistance. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-130971 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, there has been a strong demand for tires for construction vehicles such as those described above to be able to handle higher vehicle speeds and heavier loads, which makes the temperature rise in the tread even more likely to become a problem.

[0005] An object of the present invention is to provide a tire for a construction vehicle that can further improve the heat dissipation efficiency of the entire tread. [Means for solving the problem]

[0006] A construction vehicle tire according to an embodiment of the present invention has a tread formed with: widthwise narrow grooves extending in the tire width direction; a central circumferential groove communicating with one end of the widthwise narrow groove and formed at a position including the tire equator line and extending in the tire circumferential direction; outer circumferential grooves communicating with the other end of the widthwise narrow groove and formed on the outer side of the widthwise narrow groove in the tire width direction and extending in the tire circumferential direction; and a plurality of slope-shaped notched grooves each communicating with the widthwise narrow groove. In the tire width direction, intermediate circumferential grooves extending in the tire circumferential direction and intersecting the widthwise narrow grooves are formed between the plurality of notched grooves. A first notched groove included in the plurality of notched grooves arranged on the outer side of the intermediate circumferential groove in the tire width direction is formed at a position spaced a distance of ¼ of the tread width from the tire equator line, and a second notched groove included in the plurality of notched grooves arranged on the inner side of the intermediate circumferential groove in the tire width direction is formed at a tire width direction position midpoint between a position where the central circumferential groove communicates with the widthwise narrow groove and a position where the intermediate circumferential groove intersects with the widthwise narrow groove. [Effects of the Invention]

[0007] In the construction vehicle tire having the above configuration, a plurality of slope-shaped notched grooves are formed in the tread, and intermediate circumferential grooves are provided between the notched grooves, so that the outside air introduced from the notched grooves passes through the groove bottom sides of the widthwise narrow grooves, generating airflows that efficiently flow into the groove bottom sides of the adjacent circumferential grooves (central circumferential groove, outer circumferential groove, intermediate circumferential groove), thereby improving the heat dissipation efficiency near the groove bottoms over the entire width of the widthwise narrow grooves, thereby increasing the heat dissipation efficiency of the entire tread. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a partially developed plan view of a tire 10 for a construction vehicle. [Figure 2] 2(a) is a cross-sectional view of the widthwise narrow groove 100 and the notched groove 110 along the tire circumferential direction, and FIG. 2(b) is a perspective view of the notched groove 110. As shown in FIG. [Figure 3] 3(a) is a cross-sectional view of the widthwise narrow groove 100 and the notched groove 210 along the tire circumferential direction, and FIG. 3(b) is a perspective view of the notched groove 210. As shown in FIG. [Figure 4] FIG. 4(a) is a plan view of the airflow generated in the tread having the configuration of this embodiment, and FIG. 4(b) is a plan view of the airflow generated in the tread having the conventional configuration. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments will be described with reference to the drawings. Note that the same or similar reference numerals are used to designate the same functions or configurations, and descriptions thereof will be omitted as appropriate.

[0010] (1) Outline of construction vehicle tire structure 1 is a partial plan view of a construction vehicle tire 10 according to this embodiment. The construction vehicle tire 10 is a pneumatic tire mounted on a dump truck or the like that travels on rough ground such as in mines.

[0011] The size of the construction vehicle tire 10 is not particularly limited, but commonly used sizes include 49, 51, 57, and 63 inches. The construction vehicle tire 10 is sometimes called an ORR (off-the-road radial) tire, but is not necessarily limited to a radial tire.

[0012] As shown in Fig. 1, a construction vehicle tire 10 has a tread 20 that comes into contact with the road surface. A plurality of circumferential grooves 30, 40, 50, 60 extending in the tire circumferential direction TC are formed in the tread 20. In addition, a plurality of widthwise narrow grooves 100 extending in the tire width direction TW are formed in the tread 20.

[0013] The construction vehicle tire 10 has a generally symmetrical shape with respect to the tire equator line CL. However, the positions of the widthwise narrow grooves 100 are slightly offset in the tire circumferential direction TC on one side and the other side of the tire equator line CL.

[0014] The circumferential groove 30 communicates with one end of the widthwise narrow groove 100. The circumferential groove 30 is formed at a position including the tire equator line CL. In this embodiment, the circumferential groove 30 constitutes a central circumferential groove.

[0015] The circumferential groove 40 communicates with the other end of the widthwise narrow groove 100. The circumferential groove 40 is formed on the outer side of the widthwise narrow groove 100 in the tire width direction TW.

[0016] The circumferential groove 50 is formed on the opposite side of the circumferential groove 40 with respect to the tire equator line CL, and has the same shape as the circumferential groove 40. In this embodiment, the circumferential grooves 40, 50 constitute outer circumferential grooves.

[0017] In this embodiment, the circumferential grooves 30, 40, 50 have a groove width of about 10 mm and a groove depth of about 100 mm (for a 63-inch tire). The groove width and groove depth can be changed as appropriate depending on the tire size or specifications, and for tires with a diameter of 49 inches to 63 inches used for construction vehicles, the groove width is generally 3 to 10 mm and the groove depth is 40 to 100 mm.

[0018] Furthermore, the circumferential grooves 40, 50, which have roughly symmetrical shapes, are formed to have the same groove width and groove depth, but the groove width and groove depth of the circumferential groove 30 and the circumferential grooves 40, 50 may be the same or different.

[0019] Since the construction vehicle tire 10 has a shape that is generally symmetrical with respect to the tire equator line CL, the configuration of the circumferential groove 40 side with respect to the tire equator line CL will be described below.

[0020] First shoulder lug grooves 80 are formed in the tread 20. The first shoulder lug grooves 80 are formed on the outer side of the widthwise narrow grooves 100 in the tire width direction TW, and communicate with the widthwise narrow grooves 100 via the circumferential grooves 40. The first shoulder lug grooves 80 extend in the tire width direction TW.

[0021] Second shoulder lug grooves 90 are formed in the tread 20. The second shoulder lug grooves 90 are formed on the outer side of the widthwise narrow grooves 100 in the tire width direction TW, open to the circumferential grooves 40, and extend outward in the tire width direction TW. The second shoulder lug grooves 90 are formed in a crank shape that bends at two locations on the outer side in the tire width direction TW. The second shoulder lug grooves 90 terminate in a shoulder land portion that is arranged between the circumferential groove 40 and the tread edge TE.

[0022] The widthwise narrow groove 100 is a narrow groove extending in the tire width direction TW. A narrow groove is a groove in which at least the groove width is smaller than the groove depth. In this embodiment, the widthwise narrow groove 100 constitutes a widthwise narrow groove.

[0023] 1, one end (end on the tire equator line CL side) of the widthwise narrow groove 100 is connected to the circumferential groove 30, and the other end (end on the outer side in the tire width direction) is connected to the circumferential groove 40. The widthwise narrow groove 100 has a curved groove portion 150 that extends from the one end outward in the tire width direction TW and to one side in the tire circumferential direction TC and curves convexly toward one side in the tire circumferential direction TC (upper side in FIG. 1), and a linear groove portion 170 that is continuous with the curved groove portion 150 and extends linearly along the tire width direction TW toward the outer side in the tire width direction TW.

[0024] In this embodiment, the width of the widthwise narrow groove 100 is about 10 mm, and the groove depth is about 100 mm (for a 63-inch tire). The groove width and groove depth can be changed as appropriate depending on the tire size or specifications, and for tires with a diameter of 49 to 63 inches used for construction vehicles, the groove width is generally 3 to 10 mm, and the groove depth is generally 40 to 100 mm.

[0025] In addition, a plurality of notched grooves 110, 210 communicating with the widthwise narrow grooves 100 are formed in the tread 20. In addition, circumferential grooves 60 extending in the tire circumferential direction TC and intersecting the widthwise narrow grooves 100 are arranged between the plurality of notched grooves 110, 210 in the tire width direction TW.

[0026] 1, among the plurality of notched grooves 110, 210, the notched groove 110 communicating with the linear groove portion 170 of the widthwise narrow groove 100 has a rectangular shape in the tread surface view. The notched groove 210 communicating with the curved groove portion 150 of the widthwise narrow groove 100 has a parallelogram shape in the tread surface view.

[0027] 2(a) and 2(b), the notched groove 110 has a slope shape that communicates with the widthwise narrow groove 100. In this embodiment, the notched groove 110 constitutes a first notched groove.

[0028] The notched groove 110 is formed at a position spaced from the tire equator line CL by a distance of ¼ of the width of the tread 20 (hereinafter referred to as the tread width). Note that the width of the tread 20 is the contact width of the tread 20 when a normal load is applied to a construction vehicle tire 10 mounted on a normal rim wheel and set to the standard internal pressure specified for the vehicle.

[0029] The width w1 of the notched groove 110 in the tire width direction TW may be 2% or more and 4% or less of the tread width. By making it 2% or more, the effect of suppressing the temperature rise of the tread 20 can be sufficiently obtained, and by making it 4% or less, the decrease in rigidity of the tread 20 can be suppressed.

[0030] Here, the "position at a distance of 1 / 4 of the tread width from the tire equator line CL" where the notch groove 110 is formed means that the central position of the notch groove 110 in the tire width direction TW is positioned within a range of approximately one notch groove 110 (i.e., approximately ±2% to ±4% of the tread width depending on the width w1 of the notch groove 110) based on a position at a distance of 1 / 4 of the tread width from the tire equator line CL.

[0031] For example, if a 63-inch construction vehicle tire 10 has a notch groove 110 with a width of approximately 50 mm, the notch groove 110 is formed so that the center position of the notch groove 110 in the tire width direction TW is located within a range of approximately ±50 mm based on a position approximately 400 mm away from the tire equator line CL, which is the "position at a distance of 1 / 4 of the tread width from the tire equator line CL."

[0032] 1, the circumferential groove 60 is disposed on the inner side in the tire width direction TW (on the tire equator line CL side) of the notched groove 110. The circumferential groove 60 extends in the tire circumferential direction TC and intersects with the widthwise narrow groove 100. The circumferential groove 60 may be disposed on the outer side in the tire width direction TW of a position spaced a distance of 1 / 10 of the tread width from the tire equator line CL. In this embodiment, the circumferential groove 60 constitutes an intermediate circumferential groove.

[0033] In this embodiment, the circumferential groove 60 has a groove width of about 10 mm and a groove depth of about 100 mm (for a 63-inch tire). The groove width and groove depth can be changed as appropriate depending on the tire size or specifications, and for tires with a diameter of 49 inches to 63 inches used for construction vehicles, the groove width is generally 3 to 10 mm and the groove depth is 40 to 100 mm.

[0034] 3(a) and 3(b), the notched groove 210 is disposed on the inner side in the tire width direction TW (tire equator line CL side) of the circumferential groove 60, and has a slope shape that communicates with the widthwise narrow groove 100. In this embodiment, the notched groove 210 constitutes a second notched groove.

[0035] The notched groove 210, which is arranged on the inner side of the circumferential groove 60 in the tire width direction TW, is formed at a tire width direction position that is the midpoint between the position where the circumferential groove 30 communicates with the widthwise narrow groove 100 and the position where the circumferential groove 60 intersects with the widthwise narrow groove 100.

[0036] The width w2 of the notched groove 210 in the tire width direction TW may be 2% or more and 4% or less of the tread width. By making it 2% or more, the effect of suppressing the temperature rise of the tread 20 can be sufficiently obtained, and by making it 4% or less, the decrease in rigidity of the tread 20 can be suppressed.

[0037] Here, the "tire width direction position of the midpoint between the position where the circumferential groove 30 communicates with the width direction narrow groove 100 and the position where the circumferential groove 60 communicates with the width direction narrow groove 100" where the notched groove 210 intersects with the width direction narrow groove 100 means that the central position of the notched groove 210 in the tire width direction TW is located within a range of approximately half the width of the notched groove 210 (that is, approximately ±1% to ±2% of the tread width depending on the width w2 of the notched groove 210) based on the tire width direction position of the midpoint between the position where the circumferential groove 30 formed at a position including the tire equator line CL communicates with the width direction narrow groove 100 and the position where the circumferential groove 60 communicates with the width direction narrow groove 100.

[0038] For example, in the case where a notched groove 210 having a width of about 50 mm is formed in a 63-inch construction vehicle tire 10, and the circumferential groove 60 is positioned at a position spaced about 200 mm from the tire equator line CL, the notched groove 210 is formed so that the center position in the tire width direction of the notched groove 210 is positioned within a range of about ±25 mm based on a position spaced about 100 mm from the tire equator line CL, as the "tire width direction position of the midpoint between the position where the circumferential groove 30 communicates with the widthwise narrow groove 100 and the position where the circumferential groove 60 intersects with the widthwise narrow groove 100."

[0039] (2) Shape of the notch groove 2(a) is a cross-sectional view along the tire circumferential direction of the widthwise narrow groove 100 and the notched groove 110. FIG.

[0040] 2(a) and 2(b), the notched groove 110 communicates with the widthwise narrow groove 100. Specifically, the notched groove 110 has a slope portion 120, which communicates with the widthwise narrow groove 100.

[0041] The slope portion 120 extends along the tire circumferential direction, and is inclined radially inward from the surface of the tread 20 toward the widthwise narrow groove 100 .

[0042] As described above, in this embodiment, the width w1 of the slope portion 120 in the tire width direction, i.e., the width w1 of the notched groove 110, is approximately 50 mm. The inclination angle θ of the slope portion 120 with respect to the surface of the tread 20 is approximately 20 degrees.

[0043] Because the notched groove 110 has a slope portion 120, when the construction vehicle tire 10 rolls, air flows along the slope portion 120 into the widthwise narrow groove 100. Specifically, the air flows along the slope portion 120, collides with the groove wall 130 of the widthwise narrow groove 100, and spreads within the widthwise narrow groove 100.

[0044] 3(a) is a cross-sectional view of the widthwise narrow groove 100 and the notched groove 210 along the tire circumferential direction, and FIG. 3(b) is a perspective view of the notched groove 210. The notched groove 210 has a slope portion 220, which communicates with the widthwise narrow groove 100.

[0045] The slope portion 220 extends along the tire circumferential direction and has a parallelogram shape in a tread surface view, and is inclined inward in the tire radial direction TR from the surface of the tread 20 toward the widthwise narrow groove 100.

[0046] The width w2 of the slope portion 220 in the tire width direction TW, that is, the width w2 of the notched groove 210 in the tire width direction, is about 50 mm. The inclination angle θ of the slope portion 220 is about 20 degrees.

[0047] As with the notched groove 110, when the construction vehicle tire 10 rolls, air flows into the widthwise narrow groove 100 along the slope portion 220. Specifically, the air flows along the slope portion 220, collides with the groove wall 230 of the widthwise narrow groove 100, and spreads within the widthwise narrow groove 100.

[0048] (3) Actions and Effects FIG. 4(a) is a plan view of the airflow generated in the tread 20 having the configuration of this embodiment, and FIG. 4(b) is a plan view of the airflow generated in the tread having a conventional configuration.

[0049] 4(b), in the widthwise narrow groove 1100 in the tread of the conventional configuration, the notched grooves 1110, 1210 are formed so that air flows smoothly in the widthwise narrow groove 1100 when the tire rotates in the tire rolling direction TRD, and a large amount of air is taken into the widthwise narrow groove 1100, thereby efficiently cooling the portion of the tread near the widthwise narrow groove 1100. However, in the tread of the conventional configuration, the air that flows into the widthwise narrow groove 1100 from the notched grooves 1110, 1210 is mainly guided to the circumferential grooves 1030 and 1040, so the heat dissipation efficiency between the notched groove 1110 and the notched groove 1210 is relatively low compared to the heat dissipation efficiency of the widthwise narrow groove 1100 between the notched groove 1110 and the circumferential groove 1040 or between the notched groove 1210 and the circumferential groove 1030. In other words, in a tread of conventional configuration, cooling was not uniform across the tire width direction, and there was room for further improvement in heat dissipation efficiency.

[0050] In this embodiment, the air that flows into the widthwise narrow groove 100 from the notched grooves 110, 210 is guided to the circumferential grooves 30 and 40, so that the portion of the tread 20 near the widthwise narrow groove 100 is cooled evenly.

[0051] In this embodiment, the circumferential groove 60 is further formed between the first notched groove 110 and the second notched groove 210, and therefore the air that flows into the widthwise narrow groove 100 from the notched grooves 110, 210 is also guided to the circumferential groove 60, thereby making it possible to effectively cool the widthwise narrow groove 100 even at a position in the tire width direction between the first notched groove 110 and the second notched groove 210. Therefore, the tread 20 can be efficiently cooled over the entire width of the widthwise narrow groove 100.

[0052] That is, in the case of the widthwise narrow groove 100 of this embodiment, the amount of air flowing in is increased by forming two notch grooves, while the positions at which the notch grooves 110 and 210 are formed are optimized, and furthermore, the tread 20 can be effectively cooled over the entire width of the widthwise narrow groove 100 by the action of the circumferential groove 60.

[0053] If the notched grooves are formed at positions displaced from the above positions, the smooth flow of air is hindered, making it difficult to cool the tread 20 evenly in the tire width direction.

[0054] Furthermore, with such a shape of the widthwise narrow grooves 100, it is not necessary to form a large number of notched grooves, and therefore it is possible to suppress the influence on other performances such as wear resistance.

[0055] That is, according to the construction vehicle tire 10, it is possible to efficiently cool the entire tread 20 while suppressing the impact on other performance. In particular, in the construction vehicle tire 10, the notched grooves 110, 210 are formed in the widthwise narrow grooves 100 at positions optimized according to the groove shape, and the circumferential grooves 60 are formed between the notched grooves 110, 210, so that it is possible to cool the entire tread 20 even more efficiently.

[0056] It should be noted that using rubber with high heat resistance is an easy way to prevent temperature rise in the tread 20. Generally, rubber with high heat resistance has poor wear resistance, but the construction vehicle tire 10 has structural features that can suppress temperature rise in the tread 20, making it possible to use rubber with excellent wear resistance, and as a result, wear resistance performance can also be improved.

[0057] In this embodiment, the notched grooves 110, 210 have sloped portions 120, 220. The sloped portions 120, 220 are inclined radially inward toward the widthwise narrow grooves, which can promote smooth air flow into the widthwise narrow grooves. This can cool the entire tread 20 more efficiently.

[0058] Although the embodiments of the present invention have been described above, the descriptions and drawings that form part of this disclosure should not be understood to limit the present invention. Various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art from this disclosure. [Explanation of symbols]

[0059] 10. Construction vehicle tires 20 Tread 30,40,50,60 Circumferential groove 80 First shoulder lug groove 90 Second shoulder lug groove 100 Thin groove in the width direction 110 First notch groove (notch groove) 120 Slope section 130 Groove Wall 210 Second notch groove (notch groove) 220 Slope section 230 Groove Wall

Claims

1. a widthwise narrow groove extending in the tire width direction; a central circumferential groove that is connected to one end of the widthwise narrow groove, is formed at a position including the tire equator line, and extends in the tire circumferential direction; an outer circumferential groove that communicates with the other end of the widthwise narrow groove and is formed on the outer side of the widthwise narrow groove in the tire width direction, and extends in the tire circumferential direction; a tread having a plurality of sloped notched grooves each communicating with the widthwise narrow groove; In the tire width direction, intermediate circumferential grooves extending in the tire circumferential direction and intersecting the widthwise narrow grooves are formed between the plurality of notched grooves, a first notched groove included in the plurality of notched grooves arranged on the outer side of the intermediate circumferential groove in the tire width direction is formed at a position spaced a distance of ¼ of a tread width from the tire equator line, A tire for a construction vehicle, wherein a second notch groove included in the plurality of notch grooves arranged on the tire widthwise inner side of the intermediate circumferential groove is formed at a tire widthwise position midway between a position where the central circumferential groove communicates with the widthwise narrow groove and a position where the intermediate circumferential groove intersects with the widthwise narrow groove.

2. The construction vehicle tire according to claim 1 , wherein the notched groove extends in the tire circumferential direction and has a slope portion that slopes inward in the tire radial direction from the surface of the tread toward the widthwise narrow groove.

3. The construction vehicle tire according to claim 1 , wherein the notched groove extends along the tire circumferential direction.

4. The construction vehicle tire according to claim 2 , wherein the notched groove extends along the tire circumferential direction.

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