JP2006044473A - Vehicular tire having rotary auxiliary blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicular tire having rotary auxiliary blades capable of realizing the low fuel consumption by substantially reducing the rolling resistance of a tire to be used for a car or other vehicle traveling at a normal speed. <P>SOLUTION: A plurality of rotary auxiliary blades 11-1 to 11-4 are provided on an outer face of a side wall part 16 of a tire 1 in a uniformly distributed manner in the tire circumferential direction. Each rotary auxiliary blade 11 comprises a rubber sheet 12, and two bars 23 to support both ends thereof from a tire body 14. As each rotary auxiliary blade 11 is shifted from an upper end position to a lower end position when the vehicle travels, the tire body 14 is deformed by the load of the vehicle 3, a space between the two bars 13 is opened, and the area viewed from the vehicle traveling direction is increased. The center position in the tire radial direction of the rotary auxiliary blades 11 is set to be in a range of 35-55% of the tire radius from a tire rotary shaft 18 to a tread face 15, and the rate of change of the area is ≥ 40% with the lower end position as a reference. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tire used for an automobile or other vehicle that travels at a certain speed. In particular, the present invention relates to a tire that can realize a reduction in fuel consumption by substantially reducing rolling resistance.

  In recent years, social demands for reducing fuel consumption of automobiles have increased, and development of fuel efficiency reduction techniques for reducing rolling resistance of tires has been actively performed (for example, Patent Documents 1 and 2). The rolling resistance of a tire is a resistance caused by a tire made of rubber and a tire cord, which are viscoelastic bodies, rotating while being bent, and causes energy loss.

  In order to reduce this rolling resistance, it is necessary to suppress deformation of the entire tire that occurs during tire rotation, or to suppress energy loss due to repeated compression motion that occurs during road surface contact. For this purpose, studies have been made to optimize the shape and structure (profile) of the tire (such as Patent Document 1) or to optimize the rubber compounding composition (such as Patent Document 2). If the rolling resistance of the tire is reduced, it can greatly contribute to the reduction in fuel consumption of the vehicle particularly during steady speed traveling such as traveling on a highway.

  However, in these conventional methods, in order to improve rolling resistance, other performances such as wear resistance and wet performance are often deteriorated. For example, the method of reducing the blending amount of carbon black as a reinforcing agent may cause a decrease in wear resistance.

  On the other hand, it is common knowledge that no special protrusion structure is provided on the outer surface of the sidewall portion of the tire except for the relief of the product name and the uneven pattern for decoration. However, there is a proposal to provide a lip-shaped protrusion in an annular shape around the tire rotation axis in the form of being inclined toward the tire rotation axis for the purpose of absorbing vibration (Patent Document 3). However, such protrusions may increase the resistance to tire rotation, but the reverse effect cannot be expected. Moreover, there is no special effect between the air flow.

On the other hand, in an aircraft wheel, it has also been proposed to provide a wheel cap or the like with a rotational force generating wing for starting rotation of the wheel before landing in order to reduce wear during landing (Patent Document 4). However, the rotational force generating blades are not provided on the wheels for steady running of the vehicle, and do not realize low fuel consumption during running.
JP 2004-983838 A JP2004-10747 JP2000-301920A JP 2002-154485 A

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide an automobile tire that can realize low fuel consumption without causing a decrease in other tire performance.

  The automobile tire of the present invention is provided on the outer surface of the sidewall portion so that a plurality of rotation auxiliary wings that convert the force received from the airflow when the vehicle travels into the rotational driving force are evenly distributed in the tire circumferential direction. It is characterized by that.

  According to a preferred aspect of the present invention, as the rotation assist wing moves from the upper end position to the lower end position during vehicle travel, the area when viewed from the vehicle travel direction increases with deformation of the tire due to vehicle load. It is provided as follows. According to a further preferred aspect, the rotation auxiliary wing is configured such that the center position in the tire radial direction is set in a region of 35 to 55% of the tire radius from the tire rotation axis to the tread surface, and the area based on the lower end position. Change rate (area change rate described later) is 40% or more. In this case, the generation of the rotational force that hinders the traveling of the vehicle due to the air resistance on the upper side of the vehicle rotation shaft is minimized, and the generation of the rotational force that promotes the traveling of the vehicle is increased on the lower side of the vehicle rotation shaft. it can. Therefore, as a whole, an auxiliary rotational driving force can be easily generated, and fuel consumption or power can be reduced.

  According to another preferred aspect of the present invention, the rotation auxiliary wing has a convex shape toward the front surface in the rotation direction, and the rear surface in the rotation direction is a concave surface or a flat surface compared to the front surface.

  Rolling resistance can be substantially reduced, and fuel consumption or power can be reduced.

  Example 1 will be described with reference to FIGS. FIG. 1 is a schematic external perspective view showing a tire according to an embodiment in an actual running state, and FIG. 2 is a plan perspective view showing a state where a rotation auxiliary wing is removed from the tire. FIG. 3 is a schematic vertical sectional view showing a state in which the tire of the example is deformed by the load of the vehicle.

  As shown in FIGS. 1 and 3, a substantially flat plate-shaped rotation auxiliary wing 11 extending along the tire radial direction and the rotation axis direction is provided on the outer surface of the sidewall portion 16 of the tire 1. According to the illustrated example, the four rotation auxiliary wings 11-1 to 11-4 are provided on the outer surfaces of the left and right sidewall portions 16 of the tire 1 so as to be evenly distributed in the circumferential direction. In addition, each rotation auxiliary wing 11 is disposed in the vicinity of the rim 25 of the wheel 2. That is, it is arranged close to the bead portion 17.

  In the example shown in FIG. 2, each rotation auxiliary wing 11 includes one rectangular rubber sheet 12 and two rods 13 that support the rubber sheet 12 from the sidewall portion 16 of the tire. The rubber sheet 12 has a cylindrical shape at both edges 12B in the tire radial direction, and a rubber sheet body 12A having an equal thickness is stretched between them. Each rod 13 is a straight thin round bar in the illustrated example, and is driven into the core portion 13B that forms the core of the cylindrical edge portion 12B of the rubber sheet 12 and the sidewall portion 16 of the tire. The root portion 13A is embedded.

  The rubber sheet 12 can be provided with a rubber composition similar to the rubber composition constituting the tire. For example, it can be provided by a composition in which a resin such as natural rubber, butadiene rubber (BR), or styrene butadiene rubber (SBR) is blended with a reinforcing agent such as carbon black and a deterioration preventing agent. On the other hand, the rod 13 can be provided by general steel, stainless steel, aluminum alloy or other metals, or can be provided by a molded product of fiber reinforced plastic. After providing the auxiliary rotation blade 11 and the tire body 14 separately by vulcanization molding, the tire 1 of the embodiment can be obtained by driving the root portion 13A of the rod 13 into a predetermined position on the outer surface of the sidewall 16. . However, depending on the case, after combining the auxiliary rotation blade 11 and the tire body 14, vulcanization by heating can be performed.

  As shown in FIG. 3 and FIG. 1, the area of the rotation auxiliary wing 11 when viewed from the vehicle traveling direction becomes large when it comes below the wheel 2 (state of 11-1), and above the wheel 2. It becomes smaller when it comes (state of 11-3). At a position below the wheel 2, the tire body 14 is subjected to pressure deformation between the road surface 4 and the wheel 2 in contact with the tread 15 due to the load of the vehicle 3. Bulge out. Thereby, the space | interval between the stick | rods 13 becomes large at the free end side of the rotation auxiliary blade 11. FIG. On the other hand, below the wheel 2, the tire sidewall 14 is curved as the tire body 14 is deformed by the load of the vehicle, so that the space between the rods 13 is reduced. Grows on the free end side. The rotation auxiliary wing 11 acts to promote the rotational drive of the wheel below the wheel 2 and generates a reverse rotational force that inhibits the rotation drive of the wheel on the wheel. By changing as described above, a rotation assisting force that promotes rotation driving as a whole is generated.

  In the specific example, the rotation auxiliary blade 11 has a rubber sheet main body 12A having a thickness of 1 mm, an interval W between the bars 13 of 5 cm, and a dimension H protruding in the vertical direction from the outer surface of the sidewall 16 of the tire of 3 cm. The tire body 14 is TOYO 12.00 R 20 14PR used for trucks, buses or light trucks. That is, the cross-sectional width of the tire (the outer dimension in the wheel axis direction excluding the character height) is 12 inches and the rim diameter is 20 inches.

  Below, the simulation performed about the rotation assistance force which the rotation assistance blade 11 produces | generates is demonstrated using FIGS. First, FIG. 4 shows basic conditions that are the premise of the simulation. The tire radius from the tire rotation axis to the tread surface was assumed to be 0.3 m, and it was assumed that the vehicle traveled at a speed of 60 km / h (16.67 m / sec).

  Next, in the graph of FIG. 5, when only one rotation auxiliary wing is provided on the tire side surface as in the above embodiment, the rotation angle from the vertex position farthest from the road surface 4 and the rotation assistance to be generated are shown. The result of simulating the relationship with force is shown. At this time, the rotation auxiliary wing 11 has an area change rate when viewed from the vehicle traveling direction, that is, an area change rate between the upper and lower end positions when projected on a plane including the tire rotation axis and the vertical axis is 50%. It was supposed to be. Here, the area change rate (%) is a value obtained by the following equation.

Area change rate (%) = (1−projected area in the traveling direction at the lower end position)
÷ Projected area in the direction of travel at the upper end position) × 100
According to the simulation result shown in FIG. 5, a positive (plus) rotation assist force is generated only in a region where the rotation angle from the apex is between 132 ° and 228 °.

  The graph of FIG. 6 shows a result obtained by a similar simulation regarding the relationship between the area change rate of the rotation auxiliary blade 11 and the obtained rotation auxiliary force in the tire 1 of the specific example described above. 2 shows the case where the center of the rotation auxiliary wing of FIG. 2 is located at a position away from the rotation axis by 11/24 of the tire outer radius, and the right half view shows the center of the rotation auxiliary wing of FIG. Shows a case where it is located at a position away from the rotation axis by 10/24 of the tire outer radius. As can be seen from the results of FIG. 6, when the center of the rotation auxiliary wing 11 is located at a location of 11/24 of the tire outer radius, only when the area ratio between the upper and lower sides of the rotation auxiliary wing 11 is 60% or more. Positive (plus) rotational assist force is generated. On the other hand, when the center of the rotation auxiliary wing 11 is located at a position of 10/24 of the outer dimension radius of the tire, the positive (plus) rotation assist in the region where the area change rate of the rotation auxiliary wing 11 is 40% or more. Force is generated.

  From the result of FIG. 6, it is known that the position of the auxiliary rotation blade 11 in the tire radial direction is very important for the expression of the auxiliary rotation force. It can be understood that the closer the rotation auxiliary blade 11 is to the tread, the less the head wind that accompanies the tire traveling, even if it is below the tire rotation axis.

Table 1 shows the simulation results of the substantial rolling resistance of the tire when the position, number, and top / bottom area ratio of the rotating auxiliary blades are changed stepwise for a tire similar to the specific example described above. Indicates. When the rotation auxiliary wing is at the same height as the tire rotation shaft 18 (in the state of 11-2 and 11-4 in FIG. 1), the rubber sheet 12 is rectangular and the interval W between the bars 13 is 5 cm. The protrusion dimension H is assumed to be 3 cm. In Table 1, the rolling resistance is indicated by an index with a value of 100 in a reference tire (TOYO 12.00 R 20 14PR, rim size 20 inch × 7.50 inch) without a rotation auxiliary wing. The rolling resistance of the reference tire was measured with a drum type rolling resistance tester under the conditions of tire air pressure 700 kPa, load 2500 kgf, measurement temperature 25 ± 1 ° C. The impact is calculated.

  As shown in Table 1, when the distance between the center position of the rotation auxiliary wing and the tire rotation shaft 18 is 40% of the outer dimension radius of the tire, if the area change rate of the rotation auxiliary wing is 50%, the tire The actual rolling resistance was reduced by 2-3%. As is known from the comparison between Examples 1-1 and 1-2, it is more effective to arrange eight than to arrange four. However, the reduction in rolling resistance is only about 1.5 times from 2% to 3%.

  On the other hand, as is known from the results of Examples 2-1 to 2-3, when the position of the rotation auxiliary wing moves away from the tire rotation axis, the area change rate of the rotation auxiliary wing is increased to 60% and 70%. However, the degree of rolling resistance reduction was small. Further, when the rotation auxiliary wing is located on the tread side from the tire shaft (Comparative Example 1), even when the area change rate of the rotation auxiliary wing is 80%, the rolling resistance is increased. It was.

  FIG. 7 shows a rotation auxiliary wing 11 ′ in a tire 1 ′ according to a modification. In the modified auxiliary rotation blade 11 ′, in the same configuration as in the above embodiment, the relatively thick rubber sheet 12 ′ and the rods 13 ′ at both ends thereof are smoothly curved in the tire rotation direction. . The cross-sectional shape of the auxiliary rotation blade 11 ′ is the same as that of a “savonium-type” windmill blade for generating power using low-speed wind, for example. With such a configuration, even if the area change rate is small, the air pressure received during traveling of the vehicle is large on the lower side of the tire rotation shaft and larger on the upper side of the tire rotation shaft. Accordingly, a driving force in the tire rotation direction can be obtained.

  In addition, it is not limited to the “savonium type” cross-sectional shape, as long as it has a convex shape toward the front surface in the rotational direction, and the rear surface in the rotational direction is concave or has a flat surface compared to the front surface. good. Further, the entire rotation auxiliary blade 11 ′ may have a cup shape.

It is a typical external appearance perspective view of the tire of the example in the actual run state. It is a planar perspective view which shows the rotation auxiliary blade of the tire of an Example. Shown in a state removed from the tire body. It is a typical vertical direction sectional view showing about the state where the tire of an example changed with the load of vehicles. It is a schematic diagram shown about the conditions simulated about the rotational drive force of the rotation auxiliary blade of FIG. It is a graph which shows the simulation result about the relationship between the rotation position of a rotation auxiliary blade, and rotational drive force. It is a graph which shows about the relationship between the area change rate ([1-area at the lower end / area at the upper end] X100) of the auxiliary rotation blade and the auxiliary rotation force. The left half view shows the case where the center of the rotation auxiliary wing of FIG. 2 is located at a position of 11/24 of the tire outer dimension radius, and the right half view shows the center of the rotation auxiliary wing of FIG. The case where it is located at a location of 10/24 of the radius is shown. It is a typical partial appearance perspective view of the tire of a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vehicle tire 11-1 to 11-4 Rotation auxiliary wing 12 Rubber sheet 13 Rod 14 Tire body 15 Tread 16 Side wall portion 18 Tire rotation shaft 2 Wheel 25 Rim 3 Vehicle 4 Road surface

Claims (5)

  A vehicle tire characterized in that a plurality of auxiliary rotation blades for converting a force received from an air flow during vehicle traveling into a rotational driving force are provided on the outer surface of the sidewall portion so as to be evenly distributed in the tire circumferential direction. .   The rotation auxiliary wing is provided so that the area when viewed from the vehicle traveling direction increases with the deformation of the tire due to the load of the vehicle as it moves from the upper end position to the lower end position during vehicle traveling. The vehicle tire according to claim 1.   Each of the rotation assist wings has a center position in the tire radial direction set in a region of 35 to 55% of the tire radius from the tire rotation axis to the tread surface, and the rate of change of the area with respect to the lower end position is 40. The vehicle tire according to claim 2, wherein the vehicle tire is at least%.   3. Each of the rotation auxiliary wings comprises a plurality of rod-shaped members driven into a tire outer wall surface along a tire radial direction, and an elastic plate-shaped member stretched between the rod-shaped members. 3. The vehicle tire according to 3. The rotation auxiliary wing has a convex shape toward the front surface in the rotation direction, and a rear surface in the rotation direction forms a concave surface or a flat surface compared to the front surface. The vehicle tire described.

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