Tire for leaning vehicle
The tilting vehicle tire addresses uneven wear by designing a narrower contact width on the inside shoulder, enhancing wear resistance and tire durability through reduced drag on the inside shoulder during high-speed turns.
Patent Information
- Application Number
- JP2024131084
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-08-07
- Publication Date
- 2026-02-20
AI Technical Summary
Tilting vehicles experience uneven wear on the inside and outside shoulders of the tires due to imbalanced ground contact during turns, leading to faster wear on the inside shoulder, which is exacerbated during high-speed cornering.
The tilting vehicle tire design features a tread surface with a narrower contact width on the inside of the vehicle mounting position, defined by θ IN <θ OUT, reducing the difference in tire circumference between the inner and outer ends of the contact patch, thereby minimizing wear on the inside shoulder.
This design improves the wear resistance of the inside shoulder by reducing drag-induced wear during high-speed cornering, maintaining tire integrity and extending tire life.
Smart Images
Figure 2026028566000001_ABST
Abstract
Description
[Technical Field]
[0001] FIELD OF THE DISCLOSURE The present disclosure relates to tires for leaning vehicles. [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] The present disclosure aims to improve the wear resistance of the shoulder portion on the inside of the vehicle mounting surface. [Means for solving the problem]
[0008] The tilting vehicle tire according to the first aspect has a tire case spanning a pair of bead portions and a tread provided on the tire radial direction outer side of the tire case, and on the tread surface seen in the tire axial cross section, an angle of a first tangent to the tire radial direction at a first position that is a first distance away from the tire maximum diameter portion toward the vehicle mounting inner side is defined as θ IN The angle of the second tangent to the tire radial direction at a second position that is the first distance away from the tire maximum diameter portion toward the vehicle mounting outer side is defined as θ OUT When this is done, θ IN <θ OUT is set to.
[0009] In the tilting vehicle tire according to the first aspect, on the tread surface as viewed in the tire axial cross section, the angle of the first tangent to the tire radial direction at a first position that is a first distance away from the tire maximum diameter portion toward the vehicle mounting inner side is defined as θ IN The angle of the second tangent to the tire radial direction at a second position that is the first distance away from the tire maximum diameter portion toward the vehicle mounting outer side is defined as θ OUT When this is done, θ IN <θ OUT is set to. In other words, in the tilting vehicle tire according to the first aspect, the radius of curvature of the tread surface in the tire axial cross section is smaller on the inner side of the tire maximum diameter portion when mounted on the vehicle than on the outer side of the tire maximum diameter portion when mounted on the vehicle.
[0010] During high-speed cornering, a greater load acts on the inside shoulder portion of the tilting vehicle tire on the outside of the corner than on the outside shoulder portion of the tilting vehicle tire on the inside of the corner, so the inside shoulder portion tends to wear out more easily.
[0011] In the tilting vehicle tire according to the first aspect, the radius of curvature of the tread surface in the tire axial cross section is smaller from the tire maximum diameter portion to the inner side when mounted on the vehicle than from the tire maximum diameter portion to the outer side when mounted on the vehicle, so the contact width (the dimension of the contact area in the tire width direction) is narrower compared to when the radius of curvature of the tread surface is large.
[0012] Here, when comparing a contact area with a wide contact width and a contact area with a narrow contact width, the difference between the radius (based on the tire rotation axis) at the inner end in the tire width direction (the end on the side of the maximum diameter part of the tire) in the contact area with a narrow contact width and the radius at the outer end in the tire width direction (the end on the side of the tread edge) of the contact area is smaller than the difference between the radius at the inner end in the tire width direction of the contact area with a wide contact width and the radius at the outer end in the tire width direction of the contact area.
[0013] As a result, the difference between the tire circumference at the inner end in the tire width direction of a contact area with a narrow contact width and the tire circumference at the outer end in the tire width direction of a contact area with a narrow contact width is smaller than the difference between the tire circumference at the inner end in the tire width direction of a contact area with a wide contact width and the tire circumference at the outer end in the tire width direction of a contact area with a wide contact width.
[0014] If there is a difference in tire circumference between the inner end and the outer end in the contact patch, the outer end in the tire width direction is dragged on the road surface relative to the inner end in the tire width direction during tire rotation, which makes the outer end in the contact patch more susceptible to wear than the inner end in the tire width direction.
[0015] Therefore, the wider the contact patch width and the greater the difference between the tire circumference at the inner end in the tire width direction and the tire circumference at the outer end in the tire width direction, the greater the drag on the road surface and the greater the wear at the outer end in the tire width direction of the contact patch. In addition, in the case of a leaning vehicle tire on the outside of a turn, a large load acts on the shoulder portion on the inside where the tire is mounted on the vehicle, so the above-mentioned wear tends to be large.
[0016] In the first aspect, in the tilting vehicle tire on the wheel on the outside of a turn to which a large load acts during high-speed cornering, the contact area with a narrow contact width on the inside of the vehicle mounting position comes into contact with the ground. The contact area with a narrow contact width that comes into contact with the road surface during high-speed cornering has a small difference in tire circumference between the outer end in the tire width direction and the inner end in the tire width direction, so wear due to dragging on the outer end of the contact area in the tire width direction can be suppressed, thereby improving the wear resistance of the shoulder portion on the inside when mounted on the vehicle.
[0017] A tilting vehicle tire according to a second aspect is a tilting vehicle tire according to the first aspect, wherein the first position and the second position are positions from the tire maximum diameter portion along the contour to a position of L / 4 when a length of the contour of the tread surface in the tire axial cross section is L, and an average angle θ of the first tangent from the tire maximum diameter portion to a position of L / 4 toward the vehicle mounting inner side IN is the average angle θ of the second tangent line between the tire maximum diameter portion and a position L / 4 away from the vehicle mounting outer side. OUT is smaller than.
[0018] In the tilting vehicle tire according to the second aspect, when the length of the contour of the tread surface in the tire axial cross section is L, the first position and the second position are positions from the maximum tire diameter portion along the contour of the tread surface to L / 4, and the average angle θ of the first tangent between the maximum tire diameter portion and the position of L / 4 toward the vehicle mounting inner side IN The average angle θ of the second tangent between the maximum tire diameter portion and the position L / 4 on the outside of the vehicle OUT It was made smaller than that.
[0019] In other words, in this tilting vehicle tire, the average radius of curvature of the tread surface from the maximum tire diameter portion to a position L / 4 toward the inside of the vehicle mounting position in the tire axial cross section is smaller than the average radius of curvature of the tread surface from the maximum tire diameter portion to a position L / 4 toward the outside of the vehicle mounting position.
[0020] This reduces the difference in tire circumference between the outer end in the tire width direction and the inner end in the tire width direction in the contact area when the tread surface comes into contact with the ground from the maximum diameter part of the tire to a position L / 4 toward the inside of the vehicle when mounted, suppressing wear due to dragging of the contact area caused by the diameter difference and improving the wear resistance of the shoulder portion on the inside of the vehicle when mounted.
[0021] In other words, in a tilting vehicle tire that runs at an angle so that the area from the maximum tire diameter portion to the L / 4 position toward the inside of the vehicle where the tire is mounted is in contact with the ground, the wear resistance of the shoulder portion on the inside of the vehicle where the tire is mounted can be improved. [Effects of the Invention]
[0022] According to the present disclosure, it is possible to improve the wear resistance of the shoulder portion on the inside of the vehicle mounting surface. [Brief explanation of the drawings]
[0023] [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 (cross-sectional view in the tire axial direction) taken along a rotation axis showing a tire for a tilting vehicle according to an embodiment. [Figure 3] FIG. 2 is a diagram illustrating the relationship between the tread surface shape and the ground contact shape. DETAILED DESCRIPTION OF THE INVENTION
[0024] Hereinafter, embodiments for carrying out the present disclosure 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 explanations 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, ratios, etc. of each element shown in the drawings do not necessarily match those in reality. Furthermore, the dimensional relationships, ratios, etc. of each element between multiple drawings do not necessarily match.
[0025] In the drawings, 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. The tire width direction can also be referred to as the tire axial direction. Furthermore, "IN" indicates the inside direction when mounted on a vehicle, and "OUT" indicates the outside direction when mounted on a vehicle.
[0026] 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 speed, an imbalance occurs between the ground contact state of the wheel 12 on the inside of the turn (left side in FIG. 1) and the ground contact state of the wheel 14 on the outside of the turn (right side in FIG. 1). For this reason, the load F14 acting on the shoulder portion 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 on the outside of the vehicle mounting of the wheel 12 on the inside of the turn. The shoulder portion will be described in detail later.
[0027] In FIG. 2, the tire 10 for a tilting vehicle according to this embodiment is a so-called radial tire, and includes a carcass 20 as an example of a tire case that straddles a bead core 18 embedded in one bead portion 16 and a bead core 18 embedded in the other bead portion 16.
[0028] The carcass 20 of this embodiment is configured to include a first carcass ply 20A disposed on the inner side of the tire, and a second carcass ply 20B disposed on the outer side of the first carcass ply 20A.
[0029] The tire width direction end portion of the first carcass ply 20A and the end portion of the second carcass ply 20B are each anchored to the bead core 18. More specifically, the tire width direction end portion of the first carcass ply 20A and the end portion of the second carcass ply 20B are each wound up around the bead core 18 from the inner side to the outer side in the tire width direction.
[0030] A spiral belt 22, which is an example of a belt and is formed by spirally winding one or more parallel rubber-coated cords, is provided on the radially outer portion of the carcass 20, in other words, on the crown portion. In the tire 10 for a tilting vehicle of this embodiment shown in Fig. 2, the spiral belt 22 is one layer, but it may be two or more layers.
[0031] A tread 24 containing rubber is provided on the outer side of the spiral belt 22 in the tire radial direction, and a side rubber 26 is provided on the outer side of the carcass 20 in the tire width direction.
[0032] Although the tread 24 of this embodiment does not have any drainage grooves formed therein, drainage grooves may be formed therein as in a normal tire.
[0033] In the tread 24 of this embodiment, when the length of the contour of the tread surface in the tire axial cross section is L, a position 1 / 4 along the contour of the tread 24 from the tire equatorial plane CL is called 1 / 4 point T4.
[0034] In the tread 24 of this embodiment, a position L / 8 from the tire equatorial plane CL along the contour of the tread 24 is called the 1 / 8 point T8, a region axially outward from this 1 / 8 point T8 is called the shoulder portion 24S, and a region between one 1 / 8 point T8 and the other 1 / 8 point T8 is called the center region 24C. In the tilting vehicle tire 10, as an example, the center region 24C mainly comes into contact with the ground when the vehicle travels straight, and the shoulder portion 24S mainly comes into contact with the ground when cornering at high speed.
[0035] The tire equatorial plane CL as the tire maximum diameter portion of the tire 10 for a tilting vehicle of this embodiment is located at the center in the tire width direction, in other words, at the center between one bead core 18 and the other bead core 18.
[0036] In the tire 10 for a tilting vehicle of this embodiment, the average angle of the first tangent line SL1 with respect to the tire radial direction from the tire equatorial plane CL portion as an example of the tire maximum diameter portion along the tread surface to a quarter point T4 as a first position on the tread surface that is a first distance away toward the vehicle mounting inner side along the tread surface is defined as θ IN The average angle of the second tangent line SL2 with respect to the tire radial direction from the tire equatorial plane CL along the tread surface to a 1 / 4 point T4 as a second position on the tread surface that is a first distance away from the tire equatorial plane CL toward the vehicle mounting outside is defined as θ OUT When this is done, θ IN <θ OUT is set to.
[0037] In this embodiment, the tread surface of the tread 24 on the vehicle-mounted outer side from the tire equatorial plane CL has a radius of curvature R OUT The tread surface of the tread 24 on the vehicle-mounted inner side from the tire equatorial plane CL to the 1 / 4 point T4 has a radius of curvature R OUT Radius of curvature R smaller than IN The arc shape is formed from the vehicle-mounted inner quarter point T4 to the vehicle-mounted inner tread edge 24E. IN The radius of curvature R OUT and radius of curvature R IN In Figure 2, the radius of curvature R OUT The imaginary line extending from the inside of the vehicle is the dotted line R VIR is shown.
[0038] The distance from the tire rotation axis (not shown) to the vehicle-mounted inner tread edge 24E IN Radius to RE IN , from the tire rotation axis to the outer tread edge 24E mounted on the vehicle OUT Radius to RE OUT , 24E from the tire equatorial plane CL to the inner tread edge mounted on the vehicle IN The distance along the tire rotation axis to IN , tire equatorial plane CL to vehicle-mounted outer tread edge 24E OUT The distance along the tire rotation axis to OUT When RE IN =REOUT , and W IN =W OUT In other words, the vehicle-mounted inner tread edge 24E IN and vehicle mounted outer tread edge 24E OUT are located symmetrically on either side of the tire equatorial plane CL.
[0039] (Action, effect) The tire 10 for a tilting vehicle of this embodiment is configured as described above, and its operation and effects will be described below. 3 shows an outline of the relationship between the tread surface (contour) and the ground contact shape of the tread 24 when viewed in cross section along the tire rotation axis. Note that the tread surface of the tread 24 is exaggerated in terms of arc shapes and the like to make the following explanation easier to understand.
[0040] In the tread 24 of the tire 10 for a tilting vehicle of this embodiment, the radius of curvature of the tread surface in the tire axial cross section is smaller from the tire equatorial plane CL (maximum tire diameter part) to the 1 / 4 point T4 on the inner side when mounted on the vehicle than from the tire equatorial plane CL to the outer side when mounted on the vehicle. Therefore, when the curvature radius of the tread surface is small (R IN ) The contact width CAW1 of the contact area CA1 is OUT ) is narrower than the contact width CAW2 of the contact area CA2.
[0041] Therefore, when comparing the contact area CA1 with a narrow contact width and the contact area CA2 with a wide contact width, the difference Δ1 between the radius (based on the tire rotation axis) at the tire widthwise inner end P1a of the contact area CA1 with a narrow contact width and the radius at the tire widthwise outer end P1b of the contact area CA1 with a narrow contact width is smaller than the difference Δ2 between the radius at the tire widthwise inner end P2a of the contact area CA2 with a wide contact width and the radius at the tire widthwise outer end P2b of the contact area CA2 with a wide contact width.
[0042] As a result, when comparing contact area CA1 with a narrow contact width and contact area CA2 with a wide contact width, the difference between the tire circumference at the tire widthwise inner end P1a of contact area CA1 with a narrow contact width and the tire circumference at the tire widthwise outer end P1b of contact area CA1 with a narrow contact width is smaller than the difference between the tire circumference at the tire widthwise inner end P2a of contact area CA2 with a wide contact width and the tire widthwise outer end P2b of contact area CA2 with a wide contact width.
[0043] In the tilting vehicle tire 10 of the wheel 14 on the inside of a turn, which is subjected to a large load during high-speed cornering, the contact width of the contact area CA1 on the inside of the vehicle mounting side is narrow, so the difference in tire circumference between the tire width direction outer end P1b of the contact area CA1 and the tire width direction inner end P1a of the contact area CA1 is small, and wear due to drag of the contact area CA1 caused by the difference in circumference can be suppressed. IN The wear resistance of the material can be improved.
[0044] [Other embodiments] The above describes one example of an embodiment of the present disclosure, but the embodiment of the present disclosure 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 disclosure.
[0045] In the tire 10 for a leaning vehicle of the above embodiment, a known cross belt layer may be provided instead of the spiral belt 22. Furthermore, although the tire 10 for a leaning vehicle of the above embodiment is a radial tire, it may also be a bias tire.
[0046] In the tire 10 for a leaning vehicle according to the above embodiment, when the vehicle-mounted inner side of the tread surface (contour) of the tread 24 is viewed in the tire axial cross section, the distance between the 1 / 4 point T4 and the vehicle-mounted inner tread end 24E IN The area from the 1 / 4 point T4 to the vehicle-mounted inner tread edge 24E was formed in an arc shape with a curvature radius R0. IN It may be formed in a straight line.
[0047] In the tire 10 for a tilting vehicle of this embodiment, the maximum tire diameter portion is located at the center in the tire width direction, but the maximum tire diameter portion may be shifted in the tire width direction from the center in the tire width direction.
[0048] [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 disclosure is believed to be a technology that can contribute to "No. 12 - Responsible Consumption and Production" and "No. 13 - Take concrete measures against climate change." [Explanation of symbols]
[0049] 10...Tilting vehicle, 16...Bead portion, 20...Carcass (tire case), 24...Tread, CL...Tire equatorial plane (maximum diameter portion of tire), T4...1 / 4 point (first position, second position), SL1...First tangent, SL2...Second tangent, θ IN ...angle of the first tangent line relative to the tire radial direction, θ OUT ...angle of the second tangent line relative to the tire radial direction, L...length of the contour line
Claims
1. a tire case spanning the pair of bead portions; a tread provided on the outer side of the tire case in the tire radial direction; and On the tread surface viewed in the tire axial cross section, the angle of a first tangent to the tire radial direction at a first position that is a first distance away from the maximum tire diameter portion toward the vehicle mounting inner side is defined as θ ＩＮ The angle of the second tangent to the tire radial direction at a second position that is the first distance away from the tire maximum diameter portion toward the vehicle mounting outer side is defined as θ ＯＵＴ When this is done, θ ＩＮ <θ ＯＵＴ is set to Tilting vehicle tires.
2. the first position and the second position are positions from the tire maximum diameter portion along the contour of the tread surface in the tire axial cross section to L / 4, where L is the length of the contour of the tread surface in the tire axial cross section, The average angle θ of the first tangent line between the maximum tire diameter portion and a position L / 4 toward the inside of the vehicle mounting position ＩＮ is the average angle θ of the second tangent line between the tire maximum diameter portion and a position L / 4 away from the vehicle mounting outer side. ＯＵＴ is smaller than 2. The tire for a tilting vehicle according to claim 1.
Citation Information
Patent Citations
Tilting control device and tilting vehicle
JP2023051041A