JP4643844B2 - Wheel with tire - Google Patents

Description

【００４５】
【発明の効果】
叙上の如く本発明は、所謂アウトセットのホイールにおいて、車体内側に向くリムシートの周長を車体外側に向くリムシートの周長よりも、所定範囲で大に設定しているため、旋回時における接地性が改善され、操縦安定性を向上することができる。
【図面の簡単な説明】
【図１】本発明の一実施例の自動車用のホイールの断面図である。
【図２】リムを拡大して示す断面図である。
【図３】（Ａ）ホイールに作用する捻りモーメントを説明する略図、（Ｂ）はホイールの捻りバネ定数を説明する略図である。
【図４】本発明のホイールの他の例を示す断面図である。
【図５】本発明のホイールに装着しうるタイヤの一例を示す断面図である。
【図６】参考例としてホイールに装着しうるタイヤの他の例を示す断面図である。
【図７】従来技術の問題点を説明するタイヤ付きホイールの略図である。
【符号の説明】
１ ホイール
２ リム
３ 車軸
４ ディスク部
４Ｓ ディスク取付け面
５、５ｏ、５ｉ リムシート
２０ 自動車用タイヤ
２２ ビード部
２１ リムシート
Ｃ 中間位置[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tire-equipped wheel for an automobile in which, in a so-called outset wheel in which a disc portion is offset to the outside of a vehicle body, the grounding property of a tire during turning is improved to improve steering stability.
[0002]
[Prior art]
FIG. 7 shows a cross-sectional view of a conventional wheel with a tire in which a vehicle tire a is mounted on a wheel b. In addition, the code | symbol b1 in a figure is the rim | limb which mounts and hold | maintains the tire a for motor vehicles, Comprising: The rim sheet | seat c which seats the bead part of the tire a is provided. Reference numeral b2 is a disk portion for attaching the wheel b to the axle, and is integrally connected to the rim b1.
[0003]
In the wheel b, the mounting surface s2 of the disc part b2 is generally positioned at the intermediate position in the tire axial direction of the rim b1 so that each member such as a brake and a suspension provided on the axle side can be accommodated inside the wheel b. A so-called outset that is offset (displaced) to the outside of the vehicle body with respect to s1 is often used.
[0004]
[Problems to be solved by the invention]
On the other hand, in a tire-equipped wheel, a large lateral force fy acts in addition to a vertical load fz during turning at high speed. At this time, in the wheel b of the outset, a torsional moment m in the direction of the arrow is generated by the forces fz and fy, and the rim seat ci facing the inside of the vehicle body faces the outside as shown by a one-dot chain line in FIG. In comparison with, wheel deformation occurs in the direction of rising from the road surface.
[0005]
Particularly, in recent years, with the increase in speed and performance of vehicles, the wheel b has been increased in diameter and width, and the offset amount e has increased with an increase in the size of the brake. As a result, the wheel deformation becomes significant, such as the torsional moment m becoming very large, and the ground contact property of the tire during turning is impaired, and the steering stability is lowered.
[0006]
Therefore, the present invention is based on the fact that the so-called outset wheel has a grounding property at the time of turning on the basis of setting the circumference of the rim seat facing the inside of the vehicle body to be larger than the circumference of the rim seat facing the outside of the vehicle body within a predetermined range. The purpose is to provide a wheel with tires for automobiles that can improve and improve the handling stability.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the invention of claim 1 of the present application includes an automobile tire and an automobile wheel provided with a disk part for mounting to an axle on a rim having a rim seat on which a bead part is seated. A wheel with tires,
The wheel offsets the disk mounting surface to the outside of the vehicle body with respect to the intermediate position in the tire axial direction between the outward rim seat facing outward and the inward rim seat facing inward when mounted.
The circumferential length Li of the inward rim seat is made larger than the circumferential length Lo of the outward rim seat in a range determined by the following calculation formula, and the bead diameter of the bead portion is the vehicle tire before the rim assembly. There has been characterized by a left right same.
0.56Y ≦ Li-Lo ≦ 1.12Y --- (1)
Y = 2π × (r × Fy + e × Fz) × W / K −−− (2)
r: radius of the wheel with the tire when the tire is assembled with a rim and a standard internal pressure and a standard load Fz are applied (unit: m)
Fy: Maximum lateral force during turning (1.2 times standard load Fz) (unit: N)
e: Offset amount between the middle position of the rim seat and the disc mounting surface (unit: m)
Fz: Standard load (unit: N)
W: Rim width (unit: m)
K: Torsion spring constant of wheel (unit: kNm / rad)
[0008]
The invention of claim 2 is characterized in that the circumferential length Li of the inward rim sheet is made larger in the range of 1.0 to 10.0 mm than the circumferential length Lo of the outward rim sheet.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing a wheel with a tire for an automobile of the present invention.
In FIG. 1, an automobile wheel 1 (hereinafter referred to as a wheel 1) includes a rim 2 that holds and holds an automobile tire 20, and a disk portion 4 that is integrally connected to the rim 2 and attaches the wheel 1 to an axle 3. With. The wheel 1 may be a light alloy wheel in which the rim 2 and the disk portion 4 are integrally formed by casting, or a steel plate wheel 1 in which the rim 2 made of steel plate and the disk portion 4 are joined by welding. It may be.
Specifically, a range obtained by the following calculation formula can be adopted as the circumference difference Li-Lo. That is,
0.56Y ≦ Li-Lo ≦ 1.12Y --- (1)
Y = 2π × (r × Fy + e × Fz) × W / K −−− (2)
The symbols in the formula are as follows.
r: radius of a wheel with a tire when a rim is assembled and a standard internal pressure and a standard load Fz are applied (unit: m),
Fy: Maximum lateral force during turning (1.2 times the standard load Fz) (unit: N),
e: Offset amount (unit: m) between the intermediate position of the rim seat and the disc mounting surface,
Fz: standard load (unit: N),
W: rim width (unit: m),
K: Torsion spring constant of wheel (unit: kNm / rad),
[0010]
As shown in FIG. 2, the rim 2 includes a pair of rim seats 5 on which the bead portions 22 of the automobile tire 20 are seated, and a flange portion 6 that rises radially outward from the outer end P in the tire axial direction of each rim seat 5. And a well portion 7 provided between the inner ends of the rim sheet 5 and recessed inward in the radial direction is integrally formed. In this example, the case where the well portion 7 is a deep bottom rim is illustrated, but the well portion 7 may be a shallow bottom rim or a flat flat bottom rim.
[0011]
Further, as shown in FIG. 1, the disk portion 4 is a substantially disk-shaped body having a hole 9 at the center, and a disk mounting surface 4S for mounting the hub of the axle 3 is formed on the side facing the inner side of the vehicle body. is doing. The disc mounting surface 4S is offset (outset) to the outside of the vehicle body with respect to the intermediate position C in the tire axial direction between the rim seats 5 and 5 on both sides, whereby brakes, suspensions, etc. disposed on the axle side are provided. Each member (not shown) is accommodated inside the wheel 1.
[0012]
Here, in the wheel with a tire, as described in FIG. 7, a lateral force fy acts in addition to the vertical load fz when turning at a high speed. At this time, in the outset wheel, the force A large torsional moment m in the direction of the arrow is generated by fz and fy. The torsional moment m causes a wheel deformation in which the rim seat facing inward of the vehicle body is lifted from the road surface as compared with the rim seat facing outward, and the grounding property of the tire during turning is impaired.
[0013]
Therefore, in the present embodiment, the circumferential length Li of the inward rim seat 5i facing the vehicle inner side by attachment to the vehicle body is formed larger than the circumferential length Lo of the outward rim seat 5o facing outward, and is caused by the wheel deformation. The lift of the inward rim seat 5i is reduced, and the ground contact property of the tire during turning is enhanced.
[0014]
Specifically, a range obtained by the following calculation formula can be adopted as the circumference difference Li-Lo. That is,
0.5Y ≦ Li-Lo ≦ 1.2Y --- (1)
Y = 2π × (r × Fy + e × Fz) × W / K −−− (2)
The symbols in the formula are as follows.
r: radius of a wheel with a tire when a rim is assembled and a standard internal pressure and a standard load Fz are applied (unit: m),
Fy: Maximum lateral force during turning (1.2 times the standard load Fz) (unit: N),
e: Offset amount (unit: m) between the intermediate position of the rim seat and the disc mounting surface,
Fz: standard load (unit: N),
W: rim width (unit: m),
K: Torsion spring constant of wheel (unit: Nm / rad),
[0015]
Note that “(r × Fy + e × Fz)” in the formula (2) is a torsional moment M generated by the forces Fy and Fz during turning as shown in FIG. “(R × Fy + e × Fz) × W / K” is a height direction (radius) between the rim seats 5o and 5i generated by the wheel deformation caused by the torsional moment M, as conceptually shown in FIG. Direction) displacement amount δy. Therefore, in other words, the value Y in the equation (2) can be said to be a value obtained by converting the radius difference between the rim sheets 5o and 5i necessary for canceling the displacement amount δy into a circumferential length difference.
[0016]
That is, the value Y indicates that the rim seats 5o and 5i are the same from the ground contact surface in an extreme turning state in which the tire is rim assembled and the vehicle is turned in a standard state where a standard internal pressure and a standard load Fz are applied. This means the circumference difference that can be height.
[0017]
Therefore, by setting the circumference difference Li-Lo in the actual wheel 1 in the range of 0.56 to 1.12 times the value Y, from the road surface of the inward rim seat 5i when the wheel deformation occurs. The lift of is reduced. As a result, the ground contact property of the tire at the time of turning can be improved, and the steering stability can be improved.
[0018]
Note that the effect of improving the grounding property is that the nominal rim width W is 6 inches or more, the nominal rim diameter D is 15 inches or more, the offset amount e is 30 mm or more, and the torsional moment M is relatively large. It works more effectively with the wheel.
[0019]
Here, the “standard internal pressure” is the air pressure determined for each tire in the standard system including the standard on which the tire is based. The maximum air pressure is JATMA, and the table “TIRE” is TRA. The maximum value described in “LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES”, “INFLATION PRESSURE” for ETRTO, but 180 kPa for tires for passenger cars.
[0020]
The “standard load Fz” is a load defined by the standard for each tire. If it is JATMA, it is the maximum load capacity, and if it is TRA, it is the maximum described in the table “TIRE LOAD LIMITS AT VARIOUS COLD INFLATION PRESSURES”. If the value is ETRTO, it is "LOAD CAPACITY".
[0021]
The reason why the “maximum lateral force Fy” is adopted as the lateral force fy is that the grounding property becomes a problem because it is a traveling state where a large lateral force is generated such as an extreme turning state. In the case of a passenger car, a lateral acceleration of about 0.5G to 1.2G acts in the extreme turning state. Therefore, in the present invention, a value that is 1.2 times the standard load Fz is adopted as the “maximum lateral force Fy”.
[0022]
Further, the “torsion spring constant K” is obtained by applying the torsional moment m to the wheel 1 and assuming that the radial displacement between the rim seats 5o and 5i generated at that time is δy and the rim width is W, according to the following equation (3). Indicated.
K = mxW / δy --- (3)
[0023]
On the other hand, in the case of a normal passenger car, the vertical load fz applied to one tire is about 3 to 7 kN, the radius r of the wheel with tire is about 250 to 350 mm, the offset amount e is about 30 to 60 mm, and the rim width W is 150 to 250 mm. The torsion spring constant K is about 400 to 800 kNm / rad .
[0024]
Therefore, in the case of the wheel 1 for a passenger car, a range of 1.0 to 10.0 mm can be adopted as the circumference difference Li-Lo.
[0025]
When the circumference difference Li-Lo is out of the range of 0.5Y to 1.2Y and out of the range of 1.0 to 10.0 mm, the effect of improving the grounding property at the time of turning becomes excessive. In particular, when the distance is larger than 1.2Y and larger than 10.0 mm, the grounding property at the time of straight traveling is deteriorated, and the steering stability may be deteriorated.
[0026]
Here, in this example, as shown in FIG. 2, since the rim seats 5o and 5i are inclined with respect to the tire axial line J0, the circumferential lengths Lo and Li differ depending on the position in the tire axial direction. . Accordingly, in the present specification, the circumferential lengths Lo and Li are defined as the circumferential lengths at the tire axial direction outer ends P (rim heel points P) of the rim sheets 5o and 5i. The intermediate position C between the rim sheets 5 and 5 is defined as the intermediate position C between the outer ends P and P in the tire axial direction. The rim diameter D is defined as the diameter on the smaller diameter side, that is, the outer end P of the outward rim sheet 5o.
[0027]
In this example, the rim seats 5o and 5i are inclined inward in the radial direction with an angle α of, for example, 5 degrees with respect to the rim reference line J1 connecting the outer ends P and P, respectively. The flange portion 6 also has a preferable case in which the flange portion 6 has an angle β of, for example, 90 degrees with respect to the rim reference line J1 and rises outward in the radial direction.
[0028]
For example, as schematically illustrated in FIG. 4, when the rim seats 5 o and 5 i and the flange portions 6 and 6 are inclined at the angles α and β with respect to the tire axial line J 0, the circumferential difference Li− Due to Lo, there is a risk that the tire 20 may change from an originally desired shape to an irregular shape. For this reason, the stress distribution inside the tire is changed, and there is a concern that the durability of the tire may be lowered or the rim may be detached during decompression. However, the structure of FIG. 4 may be used.
[0029]
Next, as the automobile tire 20 to be mounted on the wheel 1, a conventional tire can be used because the circumferential difference Li-Lo is relatively small. In other words, as schematically shown in FIG. 5, the rim previous state, the bead diameter is left right same tire bead portion 22, i.e., the circumferential length To of outward bead seat 21o facing outboard, inwardly A tire having the same circumferential length Ti of the bead sheet 21i can be used.
[0030]
As schematically shown in FIG. 6, the vehicle tire 20 of the reference example has a circumferential length Ti of the inward bead sheet 21i larger than the circumferential length To of the outward bead sheet 21o in a predetermined range before the rim assembly. It is said that .
[0031]
Specifically, the vehicle tire 20 includes a sidewall portion 23 extending radially outward from the left and right bead portions 22 and a tread portion 24 connecting the outer ends thereof.
[0032]
The bead portion 22 includes bead seats 21i and 21o seated on the rim seats 5i and 5o, and a bead reference line J2 connecting the outer ends Q and Q of the bead seats 21i and 21o in the tire axial direction is the tire shaft. It is inclined with respect to the direction line J0 in the same direction as the rim reference line J1. That is, the circumferential lengths Ti and To measured at the outer end Q are in a relationship of Ti> To, thereby balancing the bead clamping force between the outer side and the inner side of the vehicle body. The tire cross-sectional shape is substantially symmetrical with respect to the perpendicular bisector JJ of the bead reference line J2.
[0033]
At this time, it is preferable that the circumference difference (Ti−To) of the bead sheets 21i and 21o is in a range of 0.5 to 1.5 times the circumference difference (Li−Lo) of the rim sheets 5i and 5o. Outside this range, the difference in bead tightening force is too large, and no improvement can be seen in the anti-rim displacement performance, the rim assembly performance, and the fitting during the rim assembly.
[0034]
The tire 20 includes a toroidal carcass 26 extending across the bead portions 22, 22 and a tough breaker layer 27 disposed outside the carcass 26 and inside the tread portion 2.
[0035]
The carcass 26 is composed of one or more carcass plies in which carcass cords are arranged at an angle of, for example, 70 ° to 90 ° with respect to the tire circumferential direction. As the carcass cord, for example, an organic fiber cord such as nylon, polyester, rayon, aromatic polyamide, or a steel cord is preferably used.
[0036]
The breaker layer 27 includes two or more breakers in which breaker cords are arranged at an angle of, for example, 10 to 35 ° with respect to the tire circumferential direction (normally two for passenger car tires and usually three to four for heavy duty tires). Consists of plies. The breaker plies are placed with different inclination directions so that the breaker cords cross each other between the plies, thereby increasing rigidity and reinforcing the tread portion 24 with an excellent tagging effect. As the breaker cord, for example, a steel cord or a high-strength aromatic polyamide fiber cord comparable to this is suitably employed.
[0037]
Here, in the tire-equipped wheel using the wheel 1, when traveling straight, a camber angle CA (unit degree) represented by the following equation (4) is generated, and based on this, a lateral force called a camber thrust is generated. In the case of this embodiment, a lateral force of 1 to 60 N is normally generated.
CA = (δy / W) × (360 / 2π) (4)
As a result, when there is a difference in load between the left and right wheels due to road undulation, a lateral force in one direction is suddenly generated, and the straightness of the vehicle tends to decrease.
[0038]
Therefore, it is necessary to reduce the lateral force in order to maintain straightness. For this purpose, in this example, a conicity in a direction that can be opposed to the camber thrust is intentionally generated to reduce the lateral force. ing.
[0039]
In order to generate the conicity, in this example, the width direction center 27M of the breaker layer 27 is set to the width center line JJ of the tire cross section that is the vertical bisector JJ of the bead reference line J2. The position is shifted by a predetermined distance H inside the vehicle.
[0040]
The distance H is preferably in the range of 1.0 to 10.0 mm. If the distance H is less than 1.0 mm, the lateral force reduction effect is insufficient, and if it exceeds 10.0 mm, the reverse lateral force increases. In either case, the effect of improving straightness cannot be expected.
[0041]
As mentioned above, although especially preferable embodiment of this invention was explained in full detail, this invention is not limited to embodiment of illustration, It can deform | transform and implement in a various aspect.
[0042]
【Example】
The aluminum wheel (rim size: 17 × 7JJ) with the structure shown in Fig. 1 and the specifications shown in Table 1 was prototyped, and conventional passenger car tires (tire size 215 / 45ZR17) were mounted, making steering stability when turning. Compared.
[0043]
(1) Steering stability when turning:
Wheels with tires are attached to all wheels of a vehicle (2000 cc, FR vehicle) at an internal pressure (230 kPa), run at high speed on a high-speed circuit on the dry asphalt road surface, and the driver's sensory evaluation of steering stability at that time Thus, the evaluation was performed by a 5-point method in which Comparative Example 1 was set to 2.5 points. A larger value is better.
[0044]
[Table 1]

[0045]
【The invention's effect】
As described above, according to the present invention, in the so-called outset wheel, the circumference of the rim seat facing the inside of the vehicle body is set larger than the circumference of the rim seat facing the outside of the vehicle body within a predetermined range. Performance can be improved, and steering stability can be improved.
[Brief description of the drawings]
FIG. 1 is a sectional view of an automobile wheel according to an embodiment of the present invention.
FIG. 2 is an enlarged sectional view showing a rim.
3A is a schematic diagram for explaining a torsional moment acting on a wheel, and FIG. 3B is a schematic diagram for explaining a torsion spring constant of the wheel.
FIG. 4 is a cross-sectional view showing another example of the wheel of the present invention.
FIG. 5 is a cross-sectional view showing an example of a tire that can be mounted on the wheel of the present invention.
FIG. 6 is a cross-sectional view showing another example of a tire that can be mounted on a wheel as a reference example .
FIG. 7 is a schematic view of a wheel with a tire for explaining the problems of the prior art.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wheel 2 Rim 3 Axle 4 Disc part 4S Disc attachment surface 5, 5o, 5i Rim seat 20 Car tire 22 Bead part 21 Rim seat C Intermediate position

Claims (3)

A tire-equipped wheel comprising an automobile tire, and a rim having a rim seat on which a bead part is seated, and an automobile wheel provided with a disk part for attachment to an axle,
The wheel offsets the disk mounting surface to the outside of the vehicle body with respect to the intermediate position in the tire axial direction between the outward rim seat facing outward and the inward rim seat facing inward when mounted.
The circumferential length Li of the inward rim seat is larger than the circumferential length Lo of the outward rim seat in a range determined by the following calculation formula,
Moreover the car tires, in rim previous state, tired wheel bead diameter of the bead portion is characterized in that it is a left-right identical.
0.56Y ≦ Li-Lo ≦ 1.12Y --- (1)
Y = 2π × (r × Fy + e × Fz) × W / K −−− (2)
r: radius of the wheel with tire when the tire is assembled with a rim and a standard internal pressure and a standard load Fz are applied (unit: m)
Fy: Maximum lateral force during turning (1.2 times standard load Fz) (unit: N)
e: Offset amount between the intermediate position of the rim seat and the disc mounting surface (unit: m)
Fz: Standard load (unit: N)
W: Rim width (unit: m)
K: Torsion spring constant of wheel (unit: kNm / rad) Before SL outward rim seat than the circumferential length Lo, tyred wheel according to claim 1, characterized in that a large circumferential length Li inward rim sheet in the range of 1.0 to 10.0 mm. The wheel with tire according to claim 1 or 2, wherein a nominal rim width is 6 (inch) or more, a nominal rim diameter is 15 (inch) or more, and the offset amount is 30 mm or more.

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