Tire for leaning vehicle

Abstract

To improve wear resistance of a shoulder part on a vehicle mounting inner side.SOLUTION: An inclination type vehicle tire 10 includes a tire case 18 extending over a pair of bead portions 16, a belt layer 28 provided on an outer side of the tire case 18 in a tire radial direction and having a cord 34 spirally wound in a tire circumferential direction, and a tread 20 provided on an outer side of the belt layer 28 in the tire radial direction.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a tire for a tilting vehicle. [Background technology]

[0002] A vehicle having three or more wheels and capable of turning while leaning like a two-wheeled vehicle has been disclosed (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2023-51041 Summary of the Invention [Problem to be solved by the invention]

[0004] One such vehicle is the Lean Multi Wheel (LMW)® vehicle. Unlike motorcycles, LMW vehicles are not restricted in the maximum lean angle during turning, and the lean angle is maintained by balancing the center of gravity and centrifugal force, so the wheels on the outside and inside of the turn are approximately equal.

[0005] On the other hand, in the case of tilting mobility vehicles (hereinafter referred to as "tilting vehicles") that have been proposed recently, the maximum tilt angle when turning is limited to prevent tipping over when stationary, and when turning at high speed, an imbalance occurs between the ground contact conditions of the wheels on the inside and outside of the turn.

[0006] Specifically, a greater load acts on the inside shoulder of the wheel on the outside of a turn than on the outside shoulder of the wheel on the inside of a turn. As a result, the inside shoulder wears out faster than the outside shoulder. In other words, a difference in the amount of wear occurs between the inside shoulder and the outside shoulder. Moreover, because the shoulders only come into contact with the ground during turns, the difference in wear cannot be reduced during straight-line driving, and the difference in wear continues to widen as driving progresses.

[0007] An object of the present invention is to improve the wear resistance of the shoulder portion on the inside of the vehicle mounting surface. [Means for solving the problem]

[0008] A tilting vehicle tire according to a first aspect includes a tire case spanning a pair of bead portions, a belt layer provided on the tire radial outer side of the tire case and having cords wound spirally in the tire circumferential direction, and a tread provided on the tire radial outer side of the belt layer, in which the number of cords per unit width along the contour of the belt layer in the tire axial cross section is smaller on the inner side mounted on the vehicle than on the outer side mounted on the vehicle.

[0009] In this tilting vehicle tire, the number of cords per unit width along the contour of the belt layer in the axial cross section on the inside of the vehicle is smaller than the number on the outside of the vehicle, so the in-plane bending rigidity of the belt layer on the inside of the vehicle is lower than that on the outside of the vehicle. Therefore, even if a large load acts on the shoulder portion on the inside of the vehicle of the wheel on the outside of a turn, slippage of the shoulder portion on the road surface can be suppressed.

[0010] Furthermore, the shoulder portion on the outer side of the vehicle on the wheel on the inside of the turn comes into contact with the ground. The load acting on this shoulder portion is smaller than that on the shoulder portion on the inner side of the wheel on the outside of the turn. Therefore, the cornering force is reduced at the shoulder portion on the outer side of the vehicle. However, since the number of cords on the outer side of the vehicle in the belt layer is greater than the number of cords on the inner side of the vehicle, the in-plane bending rigidity is higher than that on the inner side of the vehicle. This allows the cornering force to be supplemented on dry road surfaces.

[0011] In a second aspect, in the tilting vehicle tire according to the first aspect, when the length of the contour of the tread surface in the tire axial cross section is L and the position of L / 8 from the tire equatorial plane along the contour is taken as the 1 / 8 point, the number of cords per unit width on the vehicle mounting inner side is smaller than the number of cords per unit width on the vehicle mounting outer side, at least within the contact area in the region axially outward from the 1 / 8 point.

[0012] In a third aspect, in the tilting vehicle tire according to the first or second aspect, the number of cords per unit width on the inner side of the vehicle mounting side is 10% or more less than the number of cords per unit width on the outer side of the vehicle mounting side.

[0013] In this tilting vehicle tire, the reduction rate of the number of cords per unit width on the inside of the vehicle relative to the number of cords per unit width on the outside of the vehicle is appropriately set, thereby preventing the difference in wear between the inside and outside of the shoulder portion on the inside of the vehicle from widening. [Effects of the Invention]

[0014] According to the present invention, the wear resistance of the shoulder portion on the inside of the vehicle mounting surface can be improved. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 2 is a front view schematically showing the state of the tilting vehicle when turning. [Figure 2] 1 is a cross-sectional view showing a tire for a tilting vehicle according to an embodiment of the present invention. [Figure 3] FIG. 10 is a cross-sectional view schematically showing tread deformation at a shoulder portion on the inside of a turn. [Figure 4] FIG. 10 is a cross-sectional view schematically showing tread deformation at a shoulder portion on the outer side of a turn. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. Components indicated by the same reference numerals in each drawing are the same or similar components. Note that duplicated descriptions and reference numerals may be omitted in the embodiments described below. Furthermore, all drawings used in the following description are schematic, and the dimensional relationships and ratios of elements shown in the drawings do not necessarily correspond to the actual ones. Furthermore, the dimensional relationships and ratios of elements between multiple drawings do not necessarily correspond to the actual ones.

[0017] In the drawings, the direction of arrow C indicates the tire circumferential direction, the direction of arrow R indicates the tire radial direction, and the direction of arrow W indicates the tire width direction. The tire radial direction means the direction perpendicular to the tire rotation axis (not shown). The tire width direction means the direction parallel to the tire rotation axis (arrow X direction). The tire width direction can also be referred to as the tire axial direction. Additionally, "IN" indicates the inside direction when mounted on a vehicle, and "OUT" indicates the outside direction when mounted on a vehicle.

[0018] 1, the tilting vehicle 100 tilts when turning, but the maximum tilt angle when turning is limited to prevent tipping over when stationary, and has the characteristic that when turning at high speeds, an imbalance occurs between the ground contact state of the wheel 12 on the inside of the turn and the ground contact state of the wheel 14 on the outside of the turn. For this reason, the load F14 acting on the shoulder portion 26 on the inside of the vehicle mounting of the wheel 14 on the outside of the turn is greater than the load F12 acting on the shoulder portion 26 on the outside of the vehicle mounting of the wheel 12 on the inside of the turn.

[0019] In FIG. 2, the tire 10 for a tilting vehicle according to this embodiment has a tire case 18, a belt layer 28, and a tread 20 provided on the outer side of the belt layer 28 in the tire radial direction.

[0020] The tire case 18 is a tire framework that spans a pair of bead portions 16 and has, for example, a carcass ply 32 that spans between a pair of bead cores 30 .

[0021] The belt layer 28 is provided on the outer side in the tire radial direction of the tire case 18, and has cords 34 wound spirally in the tire circumferential direction. The cords 34 are, for example, steel cords. With regard to the number of cords 34 per unit width (for example, 25 mm) along the contour of the belt layer 28 in the tire axial cross section, the number on the inner side fitted to the vehicle is smaller than the number on the outer side fitted to the vehicle.

[0022] Specifically, if the length of the contour of the tread surface in the tire axial cross section is L and the position along the contour that is L / 8 from the tire equatorial plane is the 1 / 8 point T, then in at least the contact zone in the region axially outward from the 1 / 8 point T, the number of cords 34 per unit width on the vehicle mounting inner side may be, for example, 10% or more less than the number of cords 34 per unit width on the vehicle mounting outer side. The number of cords 34 per unit width can be adjusted by changing the axial feeding speed of the tire when winding the cords 34 spirally in the tire circumferential direction. The lower limit of the number of cords 34 per unit width is determined by the performance required of the tire, such as strength.

[0023] (action) This embodiment is configured as described above, and its operation will be described below. Referring to Fig. 2, in the tire 10 for a leaning vehicle according to this embodiment, the number of cords 34 per unit width along the contour of the belt layer 28 in the tire axial cross section is smaller on the vehicle-mounted inner side than on the vehicle-mounted outer side, so that the in-plane bending rigidity of the belt layer 28 on the vehicle-mounted inner side is lower than that on the vehicle-mounted outer side. Therefore, even if a large load acts on the shoulder portion 26 on the vehicle-mounted inner side of the wheel 14 on the outside of a turn, it is possible to suppress slippage of the shoulder portion 26 on the road surface 36 (Figs. 3 and 4).

[0024] 3 schematically shows tread deformation at the shoulder 26 on the inside of a turn. At the shoulder 26 on the inside of a turn, the number of cords 34 per unit width is large, so the in-plane bending rigidity of the belt layer 28 is high. Therefore, when a cornering force is input to the shoulder 26 from the road surface 36, the belt layer 28 is less likely to deform, and the position of the tread 20 in close contact with the road surface 36 and the belt layer 28 become increasingly misaligned. This results in greater deformation of the tread 20.

[0025] 4 schematically shows tread deformation at the shoulder 26 on the outside of a turn. At the shoulder 26 on the outside of a turn, there are fewer cords 34 per unit width, so the in-plane bending rigidity of the belt layer 28 is low. Therefore, when a cornering force from the road surface 36 is input to the shoulder 26, the belt layer 28 is more likely to deform, and the gap between the position of the tread 20 in close contact with the road surface 36 and the belt layer 28 is smaller. This reduces deformation of the tread 20, suppressing slippage and therefore wear.

[0026] In particular, by appropriately setting the reduction rate of the number of cords 34 per unit width on the inside of the vehicle relative to the number of cords 34 per unit width on the outside of the vehicle, the difference in wear of the shoulder portion 26 on the inside of the vehicle is prevented from widening between the inside of the vehicle and the outside of the vehicle.

[0027] 3, the shoulder 26 on the vehicle-mounted outer side of the wheel 12 on the inside of the turn comes into contact with the road surface 36. The load acting on this shoulder 26 is smaller than that on the vehicle-mounted inner side of the wheel 14 on the outside of the turn. Therefore, the cornering force is reduced at the vehicle-mounted outer side of the shoulder 26. However, since the number of cords 34 on the vehicle-mounted outer side of the belt layer 28 is greater than the number of cords 34 on the vehicle-mounted inner side, the in-plane bending rigidity is higher than that on the vehicle-mounted inner side. Therefore, cornering force on dry road surfaces can be supplemented.

[0028] In this way, according to this embodiment, it is possible to improve the wear resistance of the shoulder portion on the inside of the vehicle mounting surface.

[0029] [Other embodiments] The above describes one example of an embodiment of the present invention, but the embodiment of the present invention is not limited to the above, and it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0030] [Contribution to the United Nations-led Sustainable Development Goals (SDGs)] The SDGs have been proposed to realize a sustainable society. One embodiment of the present invention is believed to be a technology that can contribute to goals such as "No. 12: Responsible Consumption and Production" and "No. 13: Take concrete measures to combat climate change." [Explanation of symbols]

[0031] 10...Tire for tilting vehicle, 12...Wheel on inside of turning, 14...Wheel on outside of turning, 16...Bead portion, 18...Tire case, 20...Tread, 26...Shoulder portion, 28...Belt layer, 34...Cord, T...1 / 8 point

Claims

1. a tire case spanning the pair of bead portions; a belt layer provided on the outer side of the tire case in the tire radial direction and having a cord wound spirally in the tire circumferential direction; a tread provided on the outer side of the belt layer in the tire radial direction, A tilting vehicle tire in which the number of cords per unit width along the contour of the belt layer in the tire axial cross section on an inner side mounted on a vehicle is smaller than the number of cords on an outer side mounted on a vehicle.

2. If the length of the contour of the tread surface in the tire axial cross section is L, and the position of L / 8 from the tire equatorial plane along the contour is the 1 / 8 point, 2. The tilting vehicle tire according to claim 1, wherein, in at least the ground contact region in the region axially outward from the 1 / 8 point, the number of cords per unit width on the vehicle mounting inner side is smaller than the number of cords per unit width on the vehicle mounting outer side.

3. 3. The tilting vehicle tire according to claim 1, wherein the number of cords per unit width on the inner side when mounted on the vehicle is 10% or more less than the number of cords per unit width on the outer side when mounted on the vehicle.

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