vehicle

Abstract

To improve responsiveness in steering, by promoting increase of ground contact areas of a tire caused by turning around an inclined king pin shaft of wheels when the wheels are started to turn.SOLUTION: A vehicle is provided with a plurality of wheels and a steering mechanism that turns front wheels of the plurality of wheels around a king pin shaft inclined toward inside of the vehicle or around a virtual king pin shaft with respect to a vertical direction. A flange symbol representing a shape of a rim flange of the wheel is J, a standard value G of a height of the rim flange of the wheel is 17.5 mm, and at least the front wheels of the plurality of wheels are specially specified wheels in which a height Gout of outer rim flanges 432a is adjusted with respect to the standard value G, where the height Gout of the outer rim flanges 432a of the specially specified wheels is less than the standard value G and is 16.5 mm or more and 17.25 or less, and is lower than a height Gin of inner rim flanges 432b.SELECTED DRAWING: Figure 8

Description

[Technical Field]

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

[0002] When a driver steers a vehicle and the vehicle turns, the tires deform as the steering starts, causing the tire's contact area to change. This will be described in detail later using Figures 4 to 7, but when a vehicle turns, the tires deform so that the tire's contact area increases as the steering starts.

[0003] Figure 16 is a graph showing the relationship between tire load and friction coefficient. As shown in Figure 16, the greater the tire load, the smaller the tire friction coefficient. Conversely, the smaller the tire load, the larger the tire friction coefficient. In other words, when the same load is applied, the larger the contact area, the greater the tire friction force that will be generated. Therefore, changes in tire contact area at the start of steering have a significant impact on the friction force generated by the tire as steering occurs, and therefore on vehicle responsiveness. For this reason, wheel rim flange shapes that control tire deformation are being studied with the aim of improving steering responsiveness. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 134304 / 1983 Summary of the Invention [Problem to be solved by the invention]

[0005] Among the wheels, the steered front wheels are configured to be rotatable around a kingpin axis or a virtual kingpin axis (hereinafter collectively referred to as the kingpin axis) which is the central axis of the kingpin (see Figures 4 and 5). The kingpin axis is generally located more inward of the vehicle than the center of the front wheels, and the kingpin axis is inclined toward the inside of the vehicle with respect to the vertical direction (see Figure 5). When a driver of a vehicle turns the steering wheel to steer the front wheels, the front wheels rotate around the inclined kingpin axis. As a result, the steered front wheels move toward the inside of the vehicle (see Figures 4 and 5), and the front tires are subjected to a load from the outer rim flange of the wheels, causing the tire sides to deform overall (see Figure 6). At this time, the deformation of the tire sides follows the shape of the outer rim flange of the front wheel. Therefore, the shape of the outer rim flange of the wheel has a significant effect on the change in tire contact area and vehicle responsiveness when steering begins.

[0006] Patent Document 1 is an example of controlling tire deformation through the shape of a wheel rim flange. Patent Document 1 discloses making the height of the rim flange on the inside of a vehicle higher than the height of the rim flange on the outside of the vehicle for a wheel. According to the invention described in Patent Document 1, even when the vehicle turns and centrifugal force is applied to the wheel on the outer wheel side in the turning direction of the vehicle, it is possible to prevent the bead portion on the inside of the tire from deforming more than the bead portion on the outside of the vehicle.

[0007] The technology described in Patent Document 1 changes the height of the wheel rim flange to prevent a decrease in steering stability due to tire deformation caused by centrifugal force when the vehicle turns. However, the technology described in Patent Document 1 does not take into consideration the effect on steering responsiveness of changes in the tire contact area when the front wheel rotates around the inclined kingpin axis at the start of steering as described above.

[0008] Therefore, an object of the present invention is to provide a vehicle capable of improving steering responsiveness by promoting an increase in the tire contact area caused by the wheel rotating around an inclined kingpin axis when steering is initiated. [Means for solving the problem]

[0009] In order to solve the above problem, a vehicle according to one embodiment of the present invention comprises: Tires and tire support wheel and and a steering mechanism that steers the front wheels among the wheels around a kingpin axis or a virtual kingpin axis that is inclined toward the inside of the vehicle with respect to the vertical direction, wherein the flange symbol representing the shape of the wheel rim flange is J and the standard value G of the height of the wheel rim flange is 17.5 mm, The tire includes a bead portion engaged with a rim flange, a tread portion in contact with a road surface, and a tire side portion connecting the bead portion and the tread portion, At least the front wheels are specially designed wheels in which the height Gout of the outer rim flange, which is the rim flange on the outer side of the vehicle, is adjusted to the standard value G, Compared to a standard wheel with the outer rim flange height Gout set based on the standard value G, the contact area between the outer rim flange and the bead is reduced, the load applied to the bead is increased, the amount of deformation of the tire side is increased, and the contact area between the tread and the road surface is increased. The height Gout of the outer rim flange of the special specification wheel is less than the standard value G, and is 16.5 mm or more and 17.25 mm or less, and is lower than the height Gin of the inner rim flange, which is the rim flange on the inside of the vehicle. It is well-structured .

[0010] The special specification wheel may have an outer rim flange height Gout of 17.0 mm.

[0011] The height Gin of the inner rim flange of a special specification wheel may not be adjusted to the standard value G and may be greater than 17.25 mm and less than or equal to 18.0 mm.

[0012] The special specification wheel may have an inner rim flange height Gin of 17.5 mm.

[0013] The special specification wheels may be provided only on the front wheels.

[0014] The special specification wheels may be provided on the front and rear wheels.

[0015] The special specification wheel may be provided with an identification mark to distinguish the special specification wheel from wheels of other shapes.

[0016] The identification mark may be a cutting ring formed annularly around the entire circumference of the outer rim flange of the special wheel. [Effects of the Invention]

[0017] According to the present invention, steering responsiveness can be improved by promoting an increase in the tire contact area caused by the wheel rotating about an inclined kingpin axis when steering is initiated. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing the configuration of a vehicle according to this embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view for explaining the basic configuration of the wheel according to the embodiment. [Figure 3] FIG. 3 is a schematic cross-sectional view showing an enlarged view of the vicinity of the rim of the wheel according to the embodiment. [Figure 4] FIG. 4 is a schematic diagram illustrating the operation of the front wheels according to the embodiment when they are steered, as viewed from above. [Figure 5] FIG. 5 is a schematic diagram illustrating the operation of the front wheels according to the embodiment when they are steered, as viewed from the front-rear direction. [Figure 6] FIG. 6 is a schematic cross-sectional view illustrating deformation of the tire of the inner front wheel during steering according to the embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view illustrating deformation of the tire of the inner front wheel during steering when the height of the outer rim flange shown in FIG. 6 is reduced. [Figure 8] FIG. 8 is a schematic cross-sectional view for explaining the height of the rim flange of the front wheel according to the embodiment. [Figure 9] FIG. 9 is a table showing the scores when the vehicles of Example 1 and Comparative Example 1 were driven. [Figure 10] FIG. 10 is a table showing the scores when the vehicles of Example 2, Example 3 and Comparative Example 2 were driven. [Figure 11] FIG. 11 is a graph showing the variation in yaw angle when the vehicle of Comparative Example 1 is steered. [Figure 12] FIG. 12 is a graph showing the variation in yaw angle when the vehicle of the first embodiment is steered. [Figure 13] FIG. 13 is a schematic diagram illustrating the operation of the front and rear wheels according to the embodiment when they are steered, as viewed from above. [Figure 14] FIG. 14 is a schematic side view of the front wheel according to the embodiment. [Figure 15] FIG. 15 is a cross-sectional view of the wheel shown in FIG. 14 taken along line AA. [Figure 16] FIG. 16 is a graph showing the relationship between the tire load and the friction coefficient. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for facilitating understanding of the invention and do not limit the present invention unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant explanation, and elements not directly related to the present invention are not shown.

[0020] Fig. 1 is a schematic diagram showing the configuration of a vehicle 100 according to this embodiment. In Fig. 1, arrows indicate the left, right, front, and rear directions of the vehicle 100. The vehicle 100 includes a drive source 200, a power transmission system 300, wheels 400, and a steering mechanism 500.

[0021] The vehicle 100 has a plurality of wheels 400, and in this embodiment, is a four-wheeled vehicle having four wheels 400. The wheels 400 include two front wheels 400A and two rear wheels 400B. Hereinafter, the front wheels 400A and the rear wheels 400B may be collectively referred to as wheels 400. Note that, hereinafter, for each wheel 400, the inside of the vehicle 100 may be simply referred to as the inside, and the outside of the vehicle 100 may be simply referred to as the outside.

[0022] The drive source 200 includes at least one of an engine and a motor. That is, the drive source 200 may be configured with an engine alone, a motor alone, or both an engine and a motor. The vehicle 100 of this embodiment is capable of both 4WD (four-wheel drive) running in which the front and rear wheels are driven, and 2WD (two-wheel drive) running in which only the front wheels or only the rear wheels are driven.

[0023] The power transmission system 300 includes a transmission 310, a propeller shaft 320, a front differential gear 330A, a front drive shaft 340A, a rear differential gear 330B, and a rear drive shaft 340B. Hereinafter, the front drive shaft 340A and the rear drive shaft 340B may be collectively referred to as the drive shaft 340.

[0024] Transmission 310 adjusts the rotation speed and direction of the driving force output from drive source 200 and transmits the driving force to propeller shaft 320. Propeller shaft 320 transmits the driving force transmitted from transmission 310 to front drive shaft 340A via front differential gear 330A. Propeller shaft 320 also transmits the driving force transmitted from transmission 310 to rear drive shaft 340B via rear differential gear 330B.

[0025] Front drive shaft 340A transmits the driving force transmitted from propeller shaft 320 to front wheels 400A. Rear drive shaft 340B transmits the driving force transmitted from propeller shaft 320 to rear wheels 400B. Steering mechanism 500 includes a steering wheel (not shown) and is configured to steer front wheels 400A of vehicle wheels 400 around kingpin axes 460 that are inclined toward the inside of the vehicle with respect to the vertical direction. When the driver of vehicle 100 turns the steering wheel, steering mechanism 500 can rotate front wheels 400A around inclined kingpin axes 460. Note that, although the present embodiment will be described taking as an example a steering mechanism having a kingpin as steering mechanism 500, a steering mechanism that does not have a kingpin (for example, a double pivot steering mechanism) may also be used. In this case, the steering mechanism without a kingpin can rotate the front wheel 400A around a virtual kingpin axis that is inclined toward the inside of the vehicle relative to the vertical direction when the driver of the vehicle 100 turns the steering wheel.

[0026] Front wheel 400A transmits the driving force transmitted from front drive shaft 340A to the road surface. Rear wheel 400B transmits the driving force transmitted from rear drive shaft 340B to the road surface. In this way, the driving force is transmitted from wheel 400 to the road surface, allowing vehicle 100 to travel. Note that hereinafter, the road surface may also be referred to as the contact surface. Next, the basic configuration of wheel 400 will be described.

[0027] Fig. 2 is a schematic cross-sectional view illustrating the basic configuration of wheel 400. As shown in Fig. 2, wheel 400 has a wheel 410 and a tire 420. Wheel 410 includes a rim 430 that supports tire 420, a hub mounting surface 440 that connects to drive shaft 340 (see Fig. 1) via a hub (not shown), and a wheel disc or spokes 450 that connects rim 430 and hub mounting surface 440. Hereinafter, wheel disc or spokes 450 will be collectively referred to as wheel disc 450.

[0028] The tire 420 includes a tread portion 422, tire side portions 424, and bead portions 426. The tread portion 422 is the portion of the tire 420 that comes into contact with the road surface. The tire side portions 424 are continuous with the tread portion 422 and are located on the inner side of the tread portion 422 in the tire radial direction.

[0029] The bead portion 426 is continuous with the tire side portion 424 and is located on the tire radially inner side of the tire side portion 424. The bead portion 426 is locked to a rim flange 432 at the radially outer end of a rim 430.

[0030] Figure 3 is a schematic cross-sectional view showing an enlarged view of the vicinity of the rim 430 of the wheel 410. As shown in Figure 3, the rim flange 432 has an outer rim flange 432a located on the outer side of the vehicle and an inner rim flange 432b located on the inner side of the vehicle.

[0031] The rim diameter φD refers to the diameter of the wheel 410 at the portion where the tire 420 fits. It can also be said that the rim diameter φD is the diameter of the wheel 410 excluding the rim flange 432. The rim width W refers to the lateral width of the wheel 410 at the portion where the tire 420 fits. It can also be said that the rim width W is the lateral width of the wheel 410 excluding the rim flange 432.

[0032] Here, the wheel 410 is usually subject to standard values ​​set by the Japan Automobile Tire Manufacturers Association (JATMA) standard (JATMA standard) or the Japanese Industrial Standards (JIS standard).

[0033] The JIS standard defines the contour and dimensions of the 5° deep rim of the wheel 410. Similar to the JIS standard, the JATMA standard also defines the contour and dimensions of the 5° deep rim of the wheel 410. Specifically, the JIS standard number "JIS D4218:2021" defines the contour and dimensions of the 5° deep rim. The basic configuration of the wheel 410 in this embodiment is defined in accordance with the contour and dimensions of the 5° deep rim in the JIS standard. However, this is not limited thereto, and the basic configuration of the wheel 410 in this embodiment may also be defined in accordance with the contour and dimensions of the 5° deep rim in the JATMA standard.

[0034] For 5° deep rims conforming to the JIS standard, the shape of the rim flange 432 recommended for each rim diameter φD is specified. To identify the shape of this rim flange 432, the JIS standard specifies several symbols (hereinafter referred to as flange symbols) that represent the shape of the rim flange 432. One of the flange symbols for the rim flange 432 is the letter "J."

[0035] For the flange symbol "J," standard values ​​are set for the rim diameter φD, rim width W, flange width B, flange height G, inner bead seat width P, outer bead seat width P1, well depth H, well width L, well position M, and flange radius R2 of the wheel 410. Specifically, for a wheel 410 with a flange symbol "J," if the rim diameter φD is 14 inches or more and 21 inches or less and the rim width W is 3 inches, the minimum flange width B is 11.0 mm, the flange height G is 17.5±1.0 mm, the minimum inner bead seat width P is 13.0 mm, the minimum outer bead seat width P1 is 13.0 mm, the minimum well depth H is 17.3 mm (however, if the maximum well position M is 43 mm or less, it may be 17.0 mm), the minimum well width L is 16.0 mm, the maximum well position M is 28.0 mm, and the minimum flange radius R2 is 9.5 mm.

[0036] In addition, for wheels 410 with flange symbol "J", when the rim diameter φD is 14 inches or more and 21 inches or less and the rim width W is 3-1 / 2 inches, the minimum flange width B is 11.0 mm, the flange height G is 17.5±1.0 mm, the minimum inner bead seat width P is 15.0 mm, the minimum outer bead seat width P1 is 17.0 mm, the minimum well depth H is 17.3 mm (however, if the maximum value of well position M is 43 mm or less, it may be 17.0 mm), the minimum well width L is 19.0 mm, the maximum well position M is 34.0 mm, and the minimum flange radius R2 is 9.5 mm.

[0037] Furthermore, for wheels 410 with flange symbol "J", when the rim diameter φD is 14 inches or more and 21 inches or less and the rim width W is 4 inches, the minimum flange width B is 11.0 mm, the flange height G is 17.5±1.0 mm, the minimum inner bead seat width P is 15.0 mm, the minimum outer bead seat width P1 is 17.0 mm, the minimum well depth H is 17.3 mm (however, if the maximum well position M is 43 mm or less, it may be 17.0 mm), the minimum well width L is 19.0 mm, the maximum well position M is 45.0 mm, and the minimum flange radius R2 is 9.5 mm.

[0038] In addition, for wheels 410 with flange symbol "J", if the rim diameter φD is 14 inches or more and 21 inches or less and the rim width W is 4.5 inches or more, the minimum flange width B is 11.0 mm, the flange height G is 17.5±1.0 mm, the minimum inner bead seat width P is 19.5 mm, the minimum outer bead seat width P1 is 19.5 mm, the minimum well depth H is 17.3 mm (however, if the maximum well position M is 43 mm or less, it may be 17.0 mm), the minimum well width L is 22.0 mm, the maximum well position M is 45.0 mm, and the minimum flange radius R2 is 9.5 mm.

[0039] In addition, for wheels 410 with flange symbol "J", if the rim diameter φD is 22 inches or more and the rim width W is 4.5 inches or more, the minimum flange width B is 11.0 mm, the flange height G is 17.5±1.0 mm, the minimum inner bead seat width P is 19.5 mm, the minimum outer bead seat width P1 is 19.5 mm, the minimum well depth H is 22.0 mm (however, for existing rims, 17.3 mm is also acceptable), the minimum well width L is 22.0 mm, the maximum well position M is 45.0 mm, and the minimum flange radius R2 is 9.5 mm.

[0040] In this way, for the flange symbol "J", the standard value G determined for the height of the rim flange 432 is determined based on 17.5 mm.

[0041] In the JIS or JATMA standards, a wheel 410 having the contour and dimensions of a 5° deep rim defined by the flange symbol "J" is hereinafter referred to as a normal specification wheel.

[0042] Incidentally, in order to improve the steering response of the vehicle 100 when steering (hereinafter also referred to as steering) the vehicle 100 to turn, it is important to increase the ground contact area of ​​the tire 420 of the front wheel 400A.

[0043] As explained with reference to FIG. 16, the tire 420 is subjected to pressure (N / m 2 ) is smaller, the coefficient of friction is larger. Therefore, if the load is the same, the contact area (m 2 ) increases, the pressure on the contact surface (N / m 2 ) can be reduced, and the coefficient of friction can be increased. If the coefficient of friction of the tire 420 can be increased, the steering response of the vehicle 100 can be improved.

[0044] Fig. 4 is a schematic diagram illustrating the behavior of front wheels 400A when they are steered from above. Fig. 4 shows the behavior of front wheels 400A when vehicle 100 is steered to the left. Of the two front wheels 400A, the left front wheel 400A on the inner side in the turning direction of vehicle 100 is referred to as inner front wheel 400Aa, and the right front wheel 400A on the outer side in the turning direction is referred to as outer front wheel 400Ab.

[0045] 4, the front wheels 400A are configured to rotate around an axis called a kingpin axis 460, which is the central axis of the kingpin. The rotation angle of the front wheels 400A around the kingpin axis 460 is configured to be different between the left and right wheels.

[0046] Specifically, the rotation angle of the front wheels 400A relative to the kingpin shaft 460 is configured to be larger for the inner front wheel 400Aa than for the outer front wheel 400Ab. This is to compensate for the difference in the radius of the trajectories of the inner front wheel 400Aa and the outer front wheel 400Ab, and is called Ackermann geometry.

[0047] When the driver of vehicle 100 turns the steering wheel to steer the front wheels 400A, the two front wheels 400A rotate around the kingpin axis 460, and the contact centers of the inner front wheel 400Aa and the outer front wheel 400Ab, shown by black circles in Figure 4, move toward the inside of the vehicle 100.

[0048] At this time, the ground contact center of the inner front wheel 400Aa moves more inward than the outer front wheel 400Ab due to the larger rotation angle. In other words, the movement amount A of the ground contact center of the inner front wheel 400Aa is greater than the movement amount B of the ground contact center of the outer front wheel 400Ab.

[0049] FIG. 5 is a schematic diagram illustrating the operation of front wheels 400A when they are steered as viewed from the front-to-rear direction. In FIG. 5, arrows indicate left, right, and up and down with vehicle 100 as the reference. FIG. 5 shows the operation of front wheels 400A when vehicle 100 is steered to the right. In FIG. 5, of the two front wheels 400A, the right front wheel 400A is the inner front wheel 400Aa, and the left front wheel 400A is the outer front wheel 400Ab. As shown in FIG. 5, kingpin shaft 460 is inclined inward at a predetermined angle with respect to the vertical direction.

[0050] Therefore, when the front wheels 400A are steered, the inner front wheel 400Aa moves toward the ground contact surface by a movement amount C shown in FIG. 5, and the outer front wheel 400Ab moves toward the ground contact surface by a movement amount D shown in FIG. 5. Here, as described with reference to FIG. 4, when steering, the movement amount A of the ground contact center of the inner front wheel 400Aa is greater than the movement amount B of the ground contact center of the outer front wheel 400Ab. Therefore, the movement amount C of the inner front wheel 400Aa shown in FIG. 5 is also greater than the movement amount D of the outer front wheel 400Ab. However, in reality, the front wheel 400A does not move toward the ground contact surface, and instead receives a reaction force from the ground contact surface, which may cause the tire 420 to collapse or the body of the vehicle 100 on the front wheel 400A side to be slightly lifted.

[0051] FIG. 6 is a schematic cross-sectional view illustrating deformation of the tire 420 of the inner front wheel 400Aa during steering. Note that FIG. 6 illustrates an example in which a standard-specification wheel is applied to the inner front wheel 400Aa. That is, in FIG. 6, the heights of the rim flanges 432 of the inner front wheel 400Aa are both 17.5 mm, i.e., the height Gout of the outer rim flange 432a, which is the rim flange 432 on the outer side of the vehicle, and the height Gin of the inner rim flange 432b, which is the rim flange 432 on the inner side of the vehicle. When the front wheel 400A is steered, the inner front wheel 400Aa moves inward, as described in FIG. 4. Furthermore, as described in FIG. 5, the inner front wheel 400Aa moves toward the ground contact surface, so as to sink into the ground contact surface.

[0052] As a result, the rim 430 of the wheel 410 of the inner front wheel 400Aa moves inward (direction D1 in FIG. 6) and toward the ground contact surface (direction D2 in FIG. 6). At this time, the bead portion 426 of the tire 420 of the inner front wheel 400Aa receives a load moving inward from the outer rim flange 432a, which is on the outer side of the vehicle, of the two rim flanges 432.

[0053] Furthermore, the bead portion 426 of the tire 420 of the inner front wheel 400Aa receives a load from the rim 430 toward the ground contact surface. As a result, the tire side portion 424 is deformed overall toward the inside, and the contact area between the tread portion 422 and the ground contact surface increases. In Figure 6, the contact area between the tread portion 422 and the ground contact surface before steering (hereinafter referred to as the contact area before steering) is represented by E1, and the contact area between the tread portion 422 and the ground contact surface when steering (hereinafter referred to as the contact area during steering) is represented by E2.

[0054] 6, as the tire 420 deforms during steering, the contact area between the tread portion 422 and the ground contact surface increases from the contact area E1 before steering to the contact area E2 during steering. In other words, the increase in the contact area between the tread portion 422 and the ground contact surface is dominated by the shape of the rim 430, which inputs a load to the bead portion 426 of the tire 420.

[0055] Figure 7 is a schematic cross-sectional view illustrating deformation of the tire 420 on the inner front wheel 400Aa during steering when the height of the outer rim flange 432a shown in Figure 6 is reduced. As shown in Figure 7, when the height of the outer rim flange 432a is reduced compared to Figure 6, the contact area between the outer rim flange 432a and the bead portion 426 is reduced, which increases the load applied to the bead portion 426 and also increases the degree of freedom of deformation of the tire side portion 424.

[0056] Therefore, the amount of deformation of the tire side portion 424 shown in FIG. 7 is greater than that of the tire side portion 424 shown in FIG. 6. As in FIG. 6, the contact area between the tread portion 422 and the ground contact surface increases as the tire side portion 424 deforms. In FIG. 7, the pre-turning contact area between the tread portion 422 and the ground contact surface before turning is represented by E1, and the turning contact area between the tread portion 422 and the ground contact surface during turning is represented by E3. Note that the pre-turning contact area E1 in FIG. 6 is assumed to be the same as the pre-turning contact area E1 in FIG. 7. In FIG. 7, the amount of deformation of the tire side portion 424 is greater than that in FIG. 6, so that the shoulder portion R, which is the connection portion between the tire side portion 424 and the tread portion 422, deforms with a smaller curvature in FIG. 7 than in FIG. 6.

[0057] As a result, the contact area E3 between the tread portion 422 and the ground contact surface during steering shown in Fig. 7 is larger than the contact area E2 between the tread portion 422 and the ground contact surface during steering shown in Fig. 6. In this way, adjusting the height of the outer rim flange 432a of the wheel 410 to be lower can promote an increase in the contact area of ​​the tire 420 due to the relationship between the kingpin axis 460 and the movement of the tire 420. In other words, when the front wheel 400A rotates around the inclined kingpin axis 460 at the start of steering, the increase in the contact area of ​​the tire 420 due to the deformation of the tire side portion 424 of the tire 420 can be promoted, thereby improving steering responsiveness.

[0058] 8 is a schematic cross-sectional view illustrating the height of the rim flange 432 of the wheel 410 of the front wheel 400A according to this embodiment. Here, the height of the rim flange 432 of a standard specification wheel is set based on the standard value G of 17.5 mm for both the outer rim flange 432a and the inner rim flange 432b.

[0059] As shown in FIG. 8, the wheel 410 of the front wheel 400A according to this embodiment is a special-specification wheel in which the height Gout of the outer rim flange 432a is adjusted to a standard value G. The height Gout of the outer rim flange 432a is lower than the height Gin of the inner rim flange 432b and is less than the standard value G, which is 17.0 mm in this embodiment. Furthermore, the tolerances are set to 0.25 mm on the positive (upper) side and 0.5 mm on the negative (lower) side, so that the height Gout of the outer rim flange 432a falls within a range of 16.5 mm to 17.25 mm. Here, the tolerance is the difference from the limit value allowed for a reference dimension. In this way, the height Gout of the outer rim flange 432a is adjusted to the standard value G and falls within an allowable range (e.g., a range of 16.5 mm to 17.25 mm) based on a height 0.5 mm lower than the standard value G (e.g., 17.0 mm).

[0060] On the other hand, the height Gin of the inner rim flange 432b is set to standard value G. That is, in this embodiment, the height Gin of the inner rim flange 432b is 17.5 mm. Furthermore, the tolerances are set such that the positive (upper) tolerance is 0.5 mm and the negative (lower) tolerance is less than 0.25 mm, so that the height Gin of the inner rim flange 432b falls within a range of more than 17.25 mm and not more than 18.0 mm. In this way, the height Gin of the inner rim flange 432b is not adjusted with respect to standard value G, but is within an allowable range based on standard value G (17.5 mm) (for example, a range of more than 17.25 mm and not more than 18.0 mm).

[0061] In this way, by adjusting the height Gout of the outer rim flange 432a to be lower than the standard value G, the increase in the contact area of ​​the tire 420 caused by the wheel 400 rotating around the inclined kingpin axis 460 at the start of steering can be promoted, thereby improving steering responsiveness.

[0062] As special specification wheels of this embodiment, Examples 1 and 2 were prepared by reducing the height Gout of the outer rim flange 432a without changing the height Gin of the inner rim flange 432b from a standard specification wheel. Also, as a special specification wheel of this embodiment, Example 3 was prepared by reducing the height Gout of the outer rim flange 432a and the height Gin of the inner rim flange 432b from a standard specification wheel. Furthermore, for comparison with Examples 1 to 3, standard specification wheels were prepared as Comparative Examples 1 and 2.

[0063] [Example 1] A special specification wheel 410 was created by changing the height Gin of the inner rim flange 432b to 17.5 mm and the height Gout of the outer rim flange 432a to 17.0 mm for a standard specification wheel with a JIS standard 5° deep rim flange with a flange symbol "J." This special specification wheel 410 was mounted on the front wheel 400A of the vehicle 100, and a standard specification wheel was mounted on the rear wheel 400B of the vehicle 100.

[0064] [Comparative Example 1] Wheels 410 of standard specifications with a JIS standard 5° deep rim flange symbol "J" are provided on both front wheels 400A and rear wheels 400B of vehicle 100.

[0065] Fig. 9 is a table showing the scores when the vehicles 100 of Example 1 and Comparative Example 1 were driven. The scores for each item are expressed as a score out of a maximum of 5. As shown in Fig. 9, it was confirmed that Example 1 had higher scores than Comparative Example 1 in all items including steering response, steering feel, stability, tracking, roll feeling, roll resonance, and ride comfort.

[0066] From the above results, it was confirmed that the sensory evaluation increased when the height Gout of the outer rim flange 432a of the front wheel 400A was reduced from 17.5 mm to 17.0 mm.

[0067] [Example 2] A special specification wheel 410 was created by changing the height Gin of the inner rim flange 432b to 17.5 mm and the height Gout of the outer rim flange 432a to 17.0 mm for a standard specification wheel with a JIS standard 5° deep rim flange with a flange symbol "J." This special specification wheel 410 was installed on both the front wheels 400A and rear wheels 400B of the vehicle 100.

[0068] [Example 3] A special specification wheel 410 was created by changing the height Gin of the inner rim flange 432b to 17.0 mm and the height Gout of the outer rim flange 432a to 17.0 mm for a standard specification wheel with a JIS standard 5° deep rim flange with a flange symbol "J." This special specification wheel 410 was installed on both the front wheels 400A and rear wheels 400B of the vehicle 100.

[0069] Comparative Example 2 Standard specification wheels 410 with a JIS standard 5° deep rim flange designation "J" were installed on both the front wheels 400A and rear wheels 400B of the vehicle 100. Note that in Comparative Example 1 and Comparative Example 2, the models of the vehicles 100 equipped with standard specification wheels 410 on both the front wheels 400A and rear wheels 400B are different. Therefore, the results of the sensory evaluation were also different.

[0070] FIG. 10 is a table showing the scores when the vehicles 100 of Example 2, Example 3, and Comparative Example 2 were driven. The scores for each item are expressed as a score out of a maximum of 5 points. As shown in FIG. 10, it was confirmed that Example 2 had a higher score than Comparative Example 2 in the items of steering response, steering response, roll feeling, roll resonance, and ride comfort. It was also confirmed that Example 3 had a higher score than Comparative Example 2 in the items of steering response and steering response. It was also confirmed that Example 2 had a higher score than Example 3 in the items of roll feeling, roll resonance, and ride comfort.

[0071] From the above results, it was confirmed that the highest sensory evaluation was achieved when the height Gout of the outer rim flange 432a of all four wheels 410 was reduced from 17.5 mm to 17.0 mm. It was also confirmed that the second highest sensory evaluation was achieved when the height Gout of the outer rim flange 432a and the height Gin of the inner rim flange 432b of all four wheels 410 were reduced from 17.5 mm to 17.0 mm. It was also confirmed that the third highest sensory evaluation was achieved when the height Gout of the outer rim flange 432a of all four wheels 410 was maintained at 17.5 mm.

[0072] As can be seen from comparing Examples 1, 2, and 3 with Comparative Examples 1 and 2, it is possible to improve the sensory evaluation, including steering responsiveness, by reducing the height Gout of the outer rim flange 432a of the front wheel 400A to 17.0 mm, which is lower than the standard value G. Furthermore, as can be seen from comparing Examples 2 and 3, it is possible to improve the sensory evaluation, including roll feeling, roll resonance, and ride comfort, by not reducing the height Gin of the inner rim flange 432b, but setting it to 17.5 mm, which is the standard value G.

[0073] If the height of the outer rim flange 432a is made too low, tracking performance will deteriorate, so the height Gout of the outer rim flange 432a is preferably 16.5 mm or more. Also, as mentioned above, if the height Gout of the outer rim flange 432a reaches the standard value G, the increase in the tire contact area caused by the wheel 400 rotating around the inclined kingpin axis 460 at the start of steering will be insufficient, so the height Gout of the outer rim flange 432a is preferably 17.25 mm or less.

[0074] Similarly, if the height of the inner rim flange 432b is made too low, roll sensation, roll resonance, and ride comfort will deteriorate, so the height Gin of the inner rim flange 432b is preferably greater than 17.25 mm. Also, if the height of the inner rim flange 432b is made too high, the increase in the tire's contact patch will decrease when the tire side portion 424 is deformed overall, so the height Gin of the inner rim flange 432b is preferably 18.0 mm or less.

[0075] Furthermore, as can be seen from a comparison between Example 1 and Comparative Example 1, providing special specification wheels 410 only on the front wheels 400A can improve the sensory evaluation, including steering response. Furthermore, as can be seen from a comparison between Example 2 and Comparative Example 2, providing special specification wheels 410 on the front and rear wheels can also improve the sensory evaluation, including steering response, compared to when the front and rear wheels are standard specification wheels.

[0076] Fig. 11 is a graph showing the variation in yaw angle when the vehicle 100 of Comparative Example 1 is steered. Fig. 12 is a graph showing the variation in yaw angle when the vehicle 100 of Example 1 is steered.

[0077] In the example shown in Fig. 11, vehicle 100 of Comparative Example 1 was subjected to 10 test runs in which the vehicle was driven straight ahead at a constant vehicle speed in the first half, and then turned at a constant vehicle speed while steering at a constant angle in the second half. As shown in Fig. 11, the results of the 10 test runs of vehicle 100 of Comparative Example 1 showed that the variation in yaw angle during turning fell within the range of variation width G.

[0078] In the example shown in Fig. 12, similar to Fig. 11, test runs were conducted 10 times in which vehicle 100 of Example 1 was driven straight ahead at a constant vehicle speed in the first half, and then turned at a constant vehicle speed while turning the steering wheel at a constant angle in the second half. As shown in Fig. 12, after conducting test runs 10 times for vehicle 100 of Example 1, the variation in yaw angle during turning fell within the range of variation width G'.

[0079] 11 and 12, the variation G' in the yaw angle during cornering of the vehicle 100 of Example 1 is smaller than the variation G in the yaw angle during cornering of the vehicle 100 of Comparative Example 1. In this way, it was confirmed that by setting the height Gout of the outer rim flange 432a of the front wheel 400A to 17.0 mm, which is lower than the standard value G, the steering responsiveness of the vehicle 100 to steering inputs is improved.

[0080] Fig. 13 is a schematic diagram illustrating the operation of front wheels 400A and rear wheels 400B when the vehicle 100 is steered to the right, as viewed from above. Fig. 13 shows the operation of front wheels 400A and rear wheels 400B when the vehicle 100 is steered to the right.

[0081] Of the two rear wheels 400B, the right rear wheel 400B on the inner side in the turning direction of the vehicle 100 is called the inner rear wheel 400Ba, and the left rear wheel 400B on the outer side in the turning direction is called the outer rear wheel 400Bb.

[0082] As described in Fig. 4, when the vehicle 100 is steered, the inner front wheel 400Aa moves inward. Also, as described in Fig. 5, the inner front wheel 400Aa moves toward the ground contact surface so as to sink into the ground contact surface.

[0083] At this time, as inner front wheel 400Aa of vehicle 100 moves inward and toward the ground contact surface, a force F1 acts from inner front wheel 400Aa to lift the front right side of the vehicle body. Force F1 lifting the front right side of the vehicle body is transmitted through the vehicle body to outer rear wheel 400Bb, which is diagonally positioned from inner front wheel 400Aa. At this time, a force pressing toward the ground contact surface is applied to outer rear wheel 400Bb, and outer rear wheel 400Bb receives a reaction force F2 from the ground contact surface.

[0084] When the outer rear wheel 400Bb receives the reaction force F2, the inner front wheel 400Aa can exert a force F3 that turns the vehicle 100. Furthermore, when the inner front wheel 400Aa exerts the force F3 that turns the vehicle 100, a yaw is generated in the vehicle body, and the outer rear wheel 400Bb generates a lateral force F4 that turns the vehicle 100.

[0085] In order to increase the response speed of the inner front wheel 400Aa, it is important to shorten the time it takes for the outer rear wheel 400Bb to receive the reaction force F2 and the time it takes for the outer rear wheel 400Bb to generate the lateral force F4.

[0086] As described in Figures 6 and 7, when a load is applied to the bead portion 426 of the tire 420 in the lateral direction and toward the ground contact surface, the shape of the shoulder portion R of the tire 420 changes depending on the height of the outer rim flange 432a.

[0087] Specifically, as shown in Figure 6, when the height of the outer rim flange 432a is high, the radius of curvature of the shoulder portion R becomes large, and when the height of the outer rim flange 432a is low, as shown in Figure 7, the radius of curvature of the shoulder portion R becomes small.

[0088] As the radius of curvature of the shoulder portion R decreases, the tire side portion 424 deforms locally, thereby reducing the rigidity of the tire 420. In other words, as the radius of curvature of the shoulder portion R increases, the tire side portion 424 does not deform locally, thereby increasing the rigidity of the tire 420. In other words, as the radius of curvature of the shoulder portion R increases, the rigidity of the tire 420 can be increased.

[0089] In this embodiment, unlike the front wheel 400A, the height of the outer rim flange 432a of the rear wheel 400B is not reduced, thereby increasing the rigidity of the tire 420 of the outer-wheel-side rear wheel 400Bb. Specifically, the height of the outer rim flange 432a of the outer-wheel-side rear wheel 400Bb is set higher than the height of the outer rim flange 432a of the inner-wheel-side front wheel 400Aa.

[0090] This allows the rigidity of the tire 420 of the outer rear wheel 400Bb to be higher than the rigidity of the tire 420 of the inner front wheel 400Aa. In this embodiment, a special specification wheel is used as the wheel 410 of the front wheel 400A, and a standard specification wheel is used as the wheel 410 of the rear wheel 400B. This allows the height of the outer rim flange 432a of the rear wheel 400B to be higher than the height of the outer rim flange 432a of the front wheel 400A.

[0091] In this way, by increasing the rigidity of the tire 420 of the outer rear wheel 400Bb, the time it takes for the outer rear wheel 400Bb to receive the reaction force F2 is shortened, and the response time until the lateral force F4 is generated is shortened.

[0092] FIG. 14 is a schematic side view of the wheel 410 of the front wheel 400A according to this embodiment. FIG. 15 is a cross-sectional view of the wheel 410 shown in FIG. 14 taken along line AA. As described above, a special specification wheel is used for the wheel 410 of the front wheel 400A according to this embodiment. In order to distinguish this special specification wheel from wheels of other shapes, such as standard specification wheels, an identification mark 480 is provided on the wheel 410 of the front wheel 400A, as shown in FIGS. 14 and 15. This makes it easier to determine whether the wheel 410 that is to be or has been attached to the vehicle 100 is a special specification wheel or another wheel.

[0093] As shown in FIGS. 14 and 15 , the identification mark 480 is composed of a cutting wheel formed in an annular shape around the entire outer surface of the outer rim flange 432a. The cutting wheel is formed by cutting the outer surface of the outer rim flange 432a in an annular shape around the entire outer surface. By forming the identification mark 480 with a cutting wheel, as shown in FIG. 15 , the identification mark 480 is formed as a recess that is recessed from the outer surface of the outer rim flange 432a toward the inner surface. This reduces the rigidity of the outer rim flange 432a. Furthermore, for example, when adjusting the height of the outer rim flange 432a of a special specification wheel by cutting, the height adjustment and the formation of the cutting wheel can be performed consecutively, simplifying the process of forming the identification mark 480. Furthermore, the cutting wheel serving as the identification mark 480 may be colored. Coloring the cutting wheel makes it easier to distinguish whether the wheel 410 is a special specification wheel or not.

[0094] While the present invention has been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is clear that those skilled in the art can conceive of various modifications and alterations within the scope of the claims, and it is understood that such modifications and alterations also fall within the technical scope of the present invention.

[0095] In the above embodiment, an example in which a special specification wheel is applied only to the front wheel 400A has been described. However, the present invention is not limited to this, and special specification wheels may be applied to both the front wheel 400A and the rear wheel 400B as in Example 2. Even in this case, since the wheel 410 of the front wheel 400A is a special specification wheel, it is possible to promote an increase in the contact area of ​​the tire 420 due to the relationship between the kingpin shaft 460 and the movement of the tire 420. As a result, it is possible to improve the steering responsiveness of the vehicle 100.

[0096] In the above embodiment, the identification mark 480 provided on the special specification wheel is formed by a cutting wheel. However, the present invention is not limited to this, and the identification mark 480 may be, for example, a letter, a number, a symbol, a graphic, or the like. [Explanation of symbols]

[0097] R shoulder section 100 vehicles 200 Drive source 300 Power Transmission System 310 Transmission 320 propeller shaft 330A front differential gear 330B rear differential gear 340 drive shaft 340A front drive shaft 340B rear drive shaft 400 wheels 400A front wheel 400Aa inner front wheel 400Ab outer front wheel 400B rear wheel 400Ba inner rear wheel 400Bb outer rear wheel 410 wheels 420 tires 422 Tread 424 Tire side 426 Bead section 430 rim 432 rim flange 432a Outer rim flange 432b inner rim flange 440 Hub mounting surface 450 Wheel Disc or Spoke 460 Kingpin shaft 480 Identification Mark 500 Steering mechanism

Claims

1. A plurality of wheels each having a tire and a wheel supporting the tire; a steering mechanism that steers the front wheels among the wheels around a kingpin axis or a virtual kingpin axis that is inclined toward the inside of the vehicle with respect to the vertical direction; Equipped with The flange symbol representing the shape of the rim flange of the wheel is J, The standard value G of the height of the rim flange of the wheel is 17.5 mm, The tire is a bead portion engaged with the rim flange; a tread portion that comes into contact with the road surface; a tire side portion connecting the bead portion and the tread portion; Including, At least the front wheel of the wheels is a special specification wheel in which a height Gout of an outer rim flange, which is the rim flange on the outer side of the vehicle, of two rim flanges is adjusted with respect to the standard value G, Compared to a normal specification wheel in which the height Gout of the outer rim flange is set based on the standard value G, the height Gout of the outer rim flange of the special specification wheel is less than the standard value G, is 16.5 mm or more and 17.25 mm or less, and is configured to be lower than the height Gin of the inner rim flange which is the rim flange on the inner side of the vehicle, so as to reduce the contact area between the outer rim flange and the bead portion, increase the load applied to the bead portion, increase the amount of deformation of the tire side portion, and increase the contact area between the tread portion and the road surface. vehicle.

2. The height Gout of the outer rim flange of the special specification wheel is 17.0 mm. The vehicle of claim 1 .

3. The height Gin of the inner rim flange of the special specification wheel is not adjusted to the standard value G and is greater than 17.25 mm and less than 18.0 mm.

3. A vehicle according to claim 1 or 2.

4. The height Gin of the inner rim flange of the special specification wheel is 17.5 mm.

4. The vehicle of claim 3.

5. The special specification wheels are provided only on the front wheels of the wheels. The vehicle of claim 1 .

6. The special specification wheels are provided on the front and rear wheels of the wheels, The vehicle of claim 1 .

7. The special specification wheel is provided with an identification mark for distinguishing the special specification wheel from wheels of other shapes. The vehicle of claim 1 .

8. The identification mark is a cutting ring formed annularly around the entire circumference of the outer rim flange of the special specification wheel.

8. The vehicle of claim 7.

Images