JP2009262833A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire can suppress the generation of eccentric wear by uniformizing the distribution of loads in the grounding surface of the tire by a simple structure. <P>SOLUTION: This pneumatic tire 1 is provided with a number of tread blocks 13a divided and formed in the grounding surface 13 of tire rubber, and a stretching and contracting member 19 buried in each tread block 13a in the tire rubber. The stretching and contracting member 19 is configured to displace the tread block 13a deformed due to heat generated by the deformation of the tread block 13a depending on the grounding state of the grounding surface 13 in a radial inside direction of the tire 1. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a pneumatic tire, and is particularly suitable for application to a pneumatic tire in which the characteristics of the tire ground contact surface are changed depending on the traveling state of the vehicle.

  The vehicle travels with only the ground contact surface of the tire in contact with the road surface. When the vehicle is turning, the vehicle can be turned accurately by the frictional force generated between the tire contact surface and the road surface. Therefore, the frictional force generated by the tire contact surface is very important for ensuring the turning performance of the vehicle, and the turning performance of the vehicle can be improved as the frictional force increases. In addition, the frictional force generated by the tire contact surface is equally important in braking performance and acceleration performance during vehicle braking and acceleration.

  Generally, when a tire is unevenly distributed in contact pressure distribution due to a change in alignment such as camber angle and toe-in / to-out, uneven wear occurs on the tire contact surface. This makes it difficult to exhibit the tire's original performance, which may greatly affect the running performance of the vehicle. Further, the tire life may be shortened due to uneven wear of the tire. That is, although the main groove remains on the grounding surface as a tire, the portion having the main groove on the grounding surface does not contact the ground when the tire is mounted on a vehicle, and other parts of the grounding surface (that is, When the portion where the main groove is lost due to wear is in contact with the ground, the tire may have to be discarded.

For this reason, various techniques for controlling the tire contact load have been proposed in order to make the tire contact pressure distribution on the ground uniform. For example, in Patent Document 1, by adjusting the maximum load position in the load distribution on the tire contact surface, the size of the adhesion area and the slip area of the tire contact surface is adjusted, and the frictional force on the tire contact surface is increased. Possible tire load distribution control devices have been proposed.
JP 2006-298332 A

  However, in the tire load distribution control device described above, a piezoelectric element is used for controlling the tire contact pressure in order to move the maximum load position in the load distribution on the tire contact surface. Therefore, a power source for expanding and contracting the tire rubber and a control logic by an accessory device such as an ECU (Electronic Control Unit) are required, and there is still an insufficient problem that the system becomes complicated.

  Therefore, the present invention has been made in view of such problems, and without using an accessory, the load distribution on the tire contact surface is made uniform with a simple structure, and the occurrence of uneven wear is suppressed. The main object is to provide a pneumatic tire that can be used.

  One aspect of the present invention for achieving the above object is a pneumatic tire comprising a large number of tread blocks divided and formed on a ground contact surface of a tire rubber, and an elastic member embedded in each tread block of the tire rubber. The elastic member is configured to displace the deformed tread block inward in the radial direction of the tire due to heat generated by the deformation of the tread block due to the ground contact state of the ground contact surface.

  Therefore, according to one aspect of the present invention, the elastic member embedded in the tire causes the tread block that has been deformed due to heat generated by the deformation of the tread block due to the ground contact state of the ground contact surface to the radial direction of the tire. It can be displaced inward, that is, in a direction away from the road surface. As a result, even if the contact load of some tread blocks increases on the tire rubber contact surface, the tread block is displaced radially inward of the tire away from the road surface. Other tread blocks with a small ground load can be dispersed. Thus, the load distribution on the contact surface of the tire rubber can be made uniform with a simple structure, and the occurrence of uneven wear can be suppressed.

  In one embodiment of the present invention, the elastic member is preferably embedded in a state where the elastic member is welded to the tire rubber in the tread block and is stretched by the welded tire rubber in a direction in which the thickness of the elastic member expands.

  As a result, the tire rubber can be displaced and pulled in the direction in which the elastic member contracts due to the heat generated when the ground contact load in some tread blocks is increased and deformed. For this reason, the tread block having a large ground load can be displaced inward in the radial direction of the tire, and the ground load can be distributed to other tread blocks. Therefore, the load distribution on the contact surface of the tire rubber can be made uniform with a simple structure.

  Furthermore, in one embodiment of the present invention, the elastic member is preferably made of a shape memory metal element that recovers to its original shape by reacting with heat. Accordingly, the tire rubber can be pulled in the original shape direction in which the shape memory metal element contracts due to heat generated by the deformation caused by the increased ground load in some tread blocks.

  For this reason, the tread block having a large contact load can be displaced in the original shape direction of the shape memory metal element, that is, inward in the radial direction of the tire, and the tread block is displaced in a direction away from the road surface, thereby The ground load in the tread block can be distributed to other tread blocks. Therefore, it is possible to realize a pneumatic tire that can make the load distribution on the contact surface of the tire rubber uniform and suppress the occurrence of uneven wear with a simple structure in which the shape memory metal element is embedded in the tread block. .

  According to the present invention, the elastic member embedded in each tread block of the tire rubber causes the deformed tread block to be deformed in the radial direction of the tire due to heat generated by the tread block being deformed by the ground contact state of the ground surface. It can be displaced inward, that is, in a direction away from the road surface. As a result, even if the contact load of some tread blocks increases on the tire rubber contact surface, the tread block is displaced radially inward of the tire away from the road surface. Other tread blocks with a small ground load can be dispersed. Thus, it is possible to provide a pneumatic tire that can uniformize the load distribution on the contact surface of the tire rubber with a simple structure and suppress the occurrence of uneven wear without using an accessory device.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a cross-sectional view in the width direction showing a schematic configuration of a pneumatic tire according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing the pneumatic tire of FIG. 1 as viewed from the side. 1 and 2 represent any one of wheels mounted on a vehicle, and a cross section of a tire 1 and a wheel 2 is shown among various elements constituting the wheel. In the case of the present embodiment, a case where a so-called run flat tire is applied as a pneumatic tire (hereinafter simply referred to as a tire) will be described, but the present invention is not limited to this, and general tires other than run flat tires are described. Needless to say, the present invention can also be applied to a hollow tire.

  As shown in FIG. 1, the tire 1 is a so-called side-reinforced run-flat tire, and can run in a flat manner when the air pressure decreases. As shown in FIG. 1, the tire 1 includes a pair of bead portions 11 and 11 in which a bead core 10 is embedded, a pair of sidewall portions 12 and 12 that extend outward from the bead portion 11 in the tire radial direction, and both sides. A grounding surface 13 extending between the wall portions 12 and 12 and a large number of tread blocks 13 a provided on the grounding surface 13 are provided. A large number of rectangular parallelepiped tread blocks 13a are arranged over the entire circumference of the ground contact surface 13 of the tire 1 at predetermined intervals in the circumferential direction.

  The bead part 11 is in contact with the wheel 2 and is a part for fixing the tire 1 to the wheel 2, and has a ring-like structure over the entire circumference of the tire 1. In addition, a carcass 14 made of, for example, a single fiber material is embedded in the pair of bead portions 11 and 11, the pair of sidewall portions 12 and 12, and the ground plane 13. The carcass 14 is a cord layer formed of a fiber such as nylon or polyester, and has a role of maintaining a tire structure. A belt layer 15 is embedded in the grounding surface 13 so as to be located outside the carcass 14.

  A reinforcing rubber 17 is embedded in each of the sidewall portions 12 so as to be located inside the inner liner 16. Each of the reinforcing rubbers 17 has high rigidity, and when the air pressure in the tire internal space 18 defined by the wheel 2 and the tire 1 is reduced by puncture or the like, the entire tire 1 is made to the wheel 2. Run-flat running is possible by supporting it. The tire 1 is not limited to a side-reinforced run-flat tire, and includes a core that supports the entire tire 1 with respect to the wheel 2 when the air pressure in the tire internal space 18 is reduced. A core-type run flat tire may be used. In addition, an air adjustment valve is attached to the wheel 2.

  In the case of such an embodiment, as shown in FIGS. 1 and 2, in addition to the above-described configuration, a position corresponding to each tread block 13a on the ground contact surface 13, that is, a shape memory as an elastic member in each tread block 13a. A metal element 19 is embedded. The shape memory metal element 19 is made of, for example, Ni—Ti (nickel / titanium) or the like, and contracts or expands due to heat generated by deformation of the tread block 13 a depending on the grounding state of the grounding surface 13. Thus, the original shape is restored (restored).

  In this case, the shape memory metal element 19 is embedded in the tread block 13a so that the contraction / expansion direction is the radial direction of the tire 1 in the tread block 13a. For this reason, as described above, the tread block 13a can be displaced in the radial direction of the tire 1 due to heat generated by the deformation of the tread block 13a.

  More specifically, as shown in FIG. 3 which is an enlarged view of a tread block 13a portion where the same reference numerals are assigned to the corresponding portions to FIG. 1, shape memory is provided at positions corresponding to the respective tread blocks 13a in the ground plane 13. A shape memory metal element 19 is embedded in a space 3 provided with a thickness b substantially larger than the thickness a of the metal element 19 (a), and at least both upper and lower surfaces of the shape memory metal element 19 in the thickness a direction are space. 3. The tire rubber around 3 is stretched and welded so that the thickness a of the shape memory metal element 19 is embedded in a state of being stretched (thickness c) and pulled (b). At this time, the relationship between the thicknesses a and c of the shape memory metal element 19 and the thickness b of the space 3 is a <c <b.

  Therefore, the ground load F is applied to the tread block 13a due to the ground contact state of the ground contact surface 13 of the tire 1 (c), and the shape memory metal element 19 is caused by the heat generated by the deformation of the tread block 13a. By recovering to the original state (shape), the surrounding tire rubber is drawn in the direction of the thickness a where the shape memory metal element 19 contracts the thickness c. It is designed to pull inward (d).

  FIG. 4 in which the same reference numerals are assigned to the corresponding parts in FIG. 1 shows that the tire 1 is grounded on the road surface with a camber angle α, and the contact load on the contact surface 13 of the tire 1 at that time, that is, the contact pressure. It is a graph showing distribution. The horizontal axis represents the position in the width direction on the ground contact surface 13 of the tire 1, and the vertical axis represents the ground pressure. In this case, as shown in the drawing, the contact pressure is not uniform in the tire width direction. This is because the camber angle α is provided for the tire 1.

  As shown in FIG. 4, the contact pressure of the tire 1 has an elliptical distribution in which the left side of the paper surface is the maximum from the center of the contact surface 13 in the width direction of the tire 1. This is because the ground contact load is applied to the left side of the paper surface from the center of the ground contact surface 13 by the camber angle α, and the tire has a circular shape. Therefore, the contact pressure between the tire 1 and the road surface is maximum on the left side from the center of the contact surface 13.

  In general, when the vehicle turns, the traveling direction of the vehicle and the direction of the tire 1 do not always coincide with each other, so that a slip angle is generated. In a range where the static friction force is not exceeded, the tread rubber (tread block 13a) follows the road surface. Therefore, the tread block 13a is displaced from the start point of the ground contact toward the end point of the ground contact. Force is generated. When the displacement of the tread block 13a increases and exceeds the static frictional force, slip occurs between the tread block 13a and the road surface, and the frictional force decreases by changing to a dynamic frictional force between the tire 1 and the road surface. Therefore, the maximum frictional force can be generated on the ground contact surface 13 only at one point in the front-rear direction of the tire 1.

  In this embodiment, the tire 1 has a shape memory metal element 19 embedded in each tread block 13a. Then, as shown in FIG. 5 in which parts corresponding to those in FIG. 4 are assigned the same reference numerals, the tread block 13a, to which a large ground load is applied depending on the traveling state of the vehicle, is converted into heat generated by the deformation of the tread block 13a. As a result, the shape memory metal element 19 is displaced inward in the radial direction of the tire 1, that is, in a direction away from the road surface, using a mechanism for restoring the shape. For this reason, it becomes possible to distribute the ground load of the tread block 13a having a large ground load to the tread block 13a having a small ground load. As a result, the contact state between the contact surface 13 and the road surface of the tire 1 can be made substantially uniform, and the frictional force of the tire 1 can be utilized to the maximum.

  As described above, according to the pneumatic tire 1 of the present embodiment, the shape memory metal element 19 is embedded in each tread block 13 a of the tire 1. And according to the running state of the vehicle, the shape memory metal element 19 reacts due to the heat generated by the deformation of the tread block 13a according to the ground contact state of the ground contact surface 13 of the tire 1 with the road surface. A mechanism was used.

  Therefore, the tread block 13a having a large ground load on the ground surface 13 is displaced inward in the radial direction of the tire 1, which is the direction in which the shape memory metal element 19 contracts, in other words, the tread block 13a is displaced in the direction away from the road surface. At this time, not all of the tread blocks 13a on the ground contact surface 13 are displaced by the same amount.

  That is, in the tread block 13a to which the ground load is applied, the shape memory metal element 19 reacts by the generation of heat due to the deformation of the tread block 13a, but in the tread block 13a to which the ground load is not applied, the heat is generated. Therefore, the shape memory metal element 19 does not react and the corresponding tread block 13a is not displaced.

  As a result, the distribution of the contact pressure on the contact surface 13 of the tire 1 is made substantially uniform, the contact load is uniformly applied to the entire contact surface 13, and the friction coefficient in the width direction of the tire 1 is made substantially uniform. The Thereby, generation | occurrence | production of the partial wear can be suppressed in the contact surface 13, and since generation | occurrence | production of a slide reduces, the utilization factor of the frictional force of the tire 1 can be improved and grip force can be increased. Thus, the load distribution on the ground contact surface 13 of the tire 1 can be made uniform and the occurrence of uneven wear can be suppressed with a simple structure without using an accessory device for displacing the tread block as in the prior art.

  The best mode for carrying out the present invention has been described above with reference to the embodiments. However, the present invention is not limited to these embodiments, and various modifications can be made without departing from the scope of the present invention. And substitutions can be added.

  For example, in the above-described embodiment, the case where the shape memory metal element 19 made of Ni-Ti is applied as the elastic member has been described. However, the present invention is not limited to this, and the main point is the embedded portion. As long as the elastic member can displace the tread block in the direction away from the road surface, other elastic members made of various materials can be widely applied.

  The present invention can be used in the automobile manufacturing industry, the automobile parts manufacturing industry, and the like.

It is sectional drawing which shows schematic structure of the pneumatic tire in one Example of this invention. It is a schematic block diagram which shows the pneumatic tire of FIG. 1 seeing from a side surface. It is sectional drawing which expands and shows a part of tread block, (a) The figure required for the description at the time of embedding a shape memory metal element, (b) The figure required for the description at the time of welding a shape memory metal element, ( c) A diagram necessary for explanation when a ground load is applied to the tread block, and (d) A diagram necessary for explanation when the shape memory metal element recovers to its original shape. 1 is a cross-sectional view showing a state in which a pneumatic tire according to the present invention is grounded on a road surface with a camber angle, and a graph showing a distribution of contact pressure on the contact surface of the pneumatic tire at that time. It is sectional drawing which shows a mode that the pneumatic tire concerning this invention displaces a tread block by a shape memory metal element, and the graph showing distribution of the contact pressure in the contact surface of the pneumatic tire at that time.

Explanation of symbols

1 ... Tire (Pneumatic tire)
DESCRIPTION OF SYMBOLS 2 ... Wheel 10 ... Bead core 11 ... Bead part 12 ... Side wall part 13 ... Ground surface 13a ... Tread block 14 ... Carcass 15 ... Belt layer 16 ... Inner liner 17 ... Reinforcement rubber 18 ... Tire internal space 19 ... Shape memory metal element ( Telescopic member)

Claims (3)

A large number of tread blocks divided and formed on the ground surface of the tire rubber;
A pneumatic tire comprising a stretchable member embedded in each tread block of the tire rubber,
The elastic member displaces the deformed tread block inward in the radial direction of the tire due to heat generated by the deformation of the tread block due to the ground contact state of the ground contact surface. Enter tire. 2. The stretchable member is welded to the tire rubber in the tread block, and is embedded in a state where the stretchable member is pulled in a direction in which the thickness of the stretchable member expands by the welded tire rubber. Pneumatic tires. The pneumatic tire according to claim 1 or 2, wherein the elastic member is formed of a shape memory metal element that recovers to its original shape by reacting to the heat.

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