JP4268363B2 - Pneumatic tire and tire deformation detection method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic tire for automobiles and a tire deformation detection method for automobiles that can quickly and accurately grasp the rolling situation of tires during traveling and can be suitably used for vehicles with anti-lock brake systems (ABS). .
[0002]
[Background Art and Problems to be Solved by the Invention]
In recent years, safety devices such as an antilock brake system (ABS) have been developed and put into practical use from the viewpoint of safety required for automobiles.
[0003]
For example, in ABS, the slip ratio is indirectly calculated from the actually measured wheel rotational speed and the estimated vehicle body speed, and braking control is performed by a brake so that the slip ratio falls within a preset range. However, in this case, since the slip ratio is obtained indirectly, there is a possibility that the error range becomes large. In addition, it is insufficient from the viewpoint of response speed, and if there is a faster response, it becomes possible to control the behavior of the vehicle more quickly and safely.
[0004]
Therefore, in recent years, it is strongly desired to directly monitor the contact state between the tire and the road surface in order to control the behavior of the automobile to a safer state more quickly.
[0005]
Therefore, as shown in FIG. 6, the inventor periodically deforms the tire skin such as the tread rubber or the sidewall rubber of the tire a at a constant cycle t when the tire a is traveling at a constant speed. However, for example, when an abnormality such as slip occurs, attention is paid to a sudden change in deformation, such as the period t increasing suddenly or the time w of the deformation itself increasing rapidly. did. And by detecting the rubber deformation of the tire skin such as tread rubber directly, the abnormal behavior can be detected more quickly and more accurately than the sensor attached to the axle, for example, and this is fed back to the control system to It was found that the behavior of can be controlled to a safer state more quickly.
[0006]
That is, the present invention is capable of quickly and accurately grasping the contact situation with the road surface of the tire based on the fact that a strain gauge for detecting the strain of the rubber is embedded in the tread rubber constituting the tire outer skin. , and it aims to provide a motor vehicle pneumatic tire and tire deformation detection method for a motor vehicle that can contribute significantly to the safety control of the motor vehicle.
[0007]
[Means for Solving the Problems]
To achieve the above object, the invention of claim 1, the outside of the tire structure comprising a carcass extending to a bead core of a bead portion from a tread portion f sidewall portions, or Toreddogo arm of the tread portion Ranaru with rubber body is disposed in the interior of Toreddogo arm, is characterized in that the embedded strain gauges for detecting the distortion of the rubber body.
[0008]
The invention of claim 1, wherein the tread rubber has a land portion of blocks or ribs are partitioned by using a tread grooves including the main grooves extending in the tire circumferential direction,
The strain gauge is embedded in a depth range in which the distance H in the tire radial direction from the groove bottom surface of the land portion and the vertical main groove is 1.6 mm or less.
[0009]
In the invention of claim 1, the strain gauge is disposed on the tread rubber, and the tread central distance is 0.25 times or less of the tread width TW from the tire equator. The arrangement is characterized in that the arrangement is 20 or less and no two exist in the same ground plane .
[0010]
The invention of claim 2 is a method for detecting deformation of an automobile tire, wherein the deformation of the tire is detected by measuring an electrical resistance value of a strain gauge of the pneumatic tire for an automobile according to claim 1. It is characterized by.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a meridional sectional view of an automotive pneumatic tire (hereinafter simply referred to as a pneumatic tire) of the present invention.
[0012]
In FIG. 1, a pneumatic tire 1 includes a tire structure 10 including a carcass 6 that extends from a tread portion 2 through a sidewall portion 3 to a bead core 5 of a bead portion 4, and on the outside of the tire structure 10. A rubber body G, which is a tire skin made of a tread rubber 2G of the tread portion 2, a side wall rubber 3G of the side wall portion 3, and a bead rubber 4G of the bead portion 4, is disposed.
[0013]
Here, the tire structure 10 forms a tire skeleton, and is constituted by a cord reinforcing member including the carcass 6. In this example, the one including the carcass 6 and the belt layer 7 disposed outside the carcass 6 and inside the tread portion 2 is illustrated.
[0014]
The carcass 6 is composed of one or more carcass plies 6A in this example, in which carcass cords are arranged at an angle of, for example, 75 ° to 90 ° with respect to the tire circumferential direction. The carcass ply 6A is provided with a series of folded portions 6b that are folded from the inside to the outside around the bead core 5 at both ends of the ply body portion 6a straddling the bead cores 5 and 5, and the ply body portion 6a and the folded portion. A bead apex rubber 8 for bead reinforcement extending in a tapered shape from the bead core 5 to the outside in the tire radial direction is disposed between the bead core 6b and the bead core 6b.
[0015]
The belt layer 7 is composed of two or more belt plies 7A and 7B in this example, in which belt cords are arranged at an angle of, for example, 10 to 45 ° with respect to the tire circumferential direction. Each belt ply 7A, 7B has a belt cord that crosses between the plies, thereby increasing belt rigidity and reinforcing the entire width of the tread portion 2 with a tagging effect.
[0016]
The rubber body G that forms a tire outer skin is disposed outside the tire structure 10, and in the present embodiment, the tread rubber 2 G, the side wall rubber 3 G, and the bead rubber 4 G that form the rubber body G. It comprises a. A strain gauge 11 is embedded in the tread rubber 2G.
[0017]
Here, as is well known, the strain gauge 11 is a sensor that detects the deformation by changing the electrical resistance of the gauge material by a given deformation, and includes a semiconductor gauge using a semiconductor as the gauge material, and the gauge material. And metal gauges using copper / nickel alloys. However, a metal gauge that is not easily affected by temperature is suitable. In particular, a foil gauge in which a gauge material is formed of a copper / nickel alloy foil can be more preferably employed from the viewpoint of strength, size (including thickness), and the like.
[0018]
Since the side wall rubber 3G and the bead rubber 4G have a large amount of deformation during running , if the strain gauge 11 is used for them, it is necessary to use a high strain type, but this high strain type is expensive. In addition, there is a concern that the strain gauge 11 itself may fail or the tire may be damaged from the embedded position due to the large amount of deformation.
[0019]
Therefore, in the present invention, by specifying the burying position within a predetermined depth range Y of the tread rubber 2G, it is possible to use a general low strain type strain gauge 11 and failure of the strain gauge 11 itself. And tire damage are prevented.
[0020]
In detail, the tread rubber 2G requires a land portion 14 composed of blocks or ribs divided by using a tread groove 13 including a longitudinal main groove 12 extending in the tire circumferential direction, as in a conventional tire. It is formed with a tread pattern according to performance. And as shown to FIG. 2 (A), (B), the tire radial direction distance H in the land part 14 from the groove bottom face 12S of the said vertical main groove 12 is in the depth range Y of 1.6 mm or less, The strain gauge 11 is embedded.
[0021]
In such a depth range Y, even if the land portion 14 is largely deformed, only a low strain of, for example, 1% or less is generated in the strain gauge 11, and therefore an inexpensive low strain type strain gauge 11 is provided. In addition, the strain gauge 11 itself can be prevented from malfunctioning or tire damage. At a position shallower than the depth range Y, the strain gauge 11 is exposed and damaged and damaged before the wear life of the tire, and at a deep position, the deformation of the tread is not sufficiently transmitted and the tire deformation is detected. It becomes difficult.
[0022]
Further, the burying position needs to be inside the peripheral edge e of the land portion 14, and in particular, a width direction in which a distance W1a of 20% of the width W1 of the land portion 14 is separated from both side edges e1 in the width direction. It is preferable that the distance W2a in the central area S1 and 20% of the length W2 of the land portion 14 is in the longitudinal central area S2 separated from both side edges e2 in the longitudinal direction.
[0023]
Further , in order to make it a part that can be reliably grounded and deformed even when going straight or turning, a tread central region Rc in which the tire axial distance L from the tire equator C is not more than 0.25 times the tread width TW as shown in FIG. In addition, a strain gauge 11 is embedded.
[0024]
If the strain gauge 11 is at least in the depth range Y within the land portion 14, as shown in FIGS. 3A to 3C, the circumferential strain detection gauge 11A, the lateral direction (the tire axial direction) ) A strain detection gauge 11B and a radial strain detection gauge 11C may be used.
[0025]
In addition, at least one strain gauge 11 is provided. Preferably, four or more, more preferably eight or more strain gauges 11 are arranged at equal intervals in the tire circumferential direction. This is because when one strain gauge 11 is used, when an abnormality such as slip occurs, a time lag T of a time required for one rotation of the tire to detect the abnormality (for example, about 0 at a traveling speed of 60 km / h). .11 seconds) occurs, but the time lag is reduced to T / 4 for four and T / 8 for eight, so that the faster the number of gauges, the faster the detection becomes possible. If the number is more than 20, two strain gauges 11 exist in the same ground plane, and the labor for collecting data is unnecessarily increased, and there is a possibility that unreasonableness may occur between the data. That is, it is arranged such that there are 4 or more and 20 or less, and 2 are not present in the same ground plane.
[0026]
Such a strain gauge 11 may be embedded in a tire after vulcanization molding by retrofitting, or may be embedded when forming a raw tire before vulcanization molding. That is, in the former, one of the blocks (corresponding to the land portion 14) is cut out from the tread portion 2 of the tire that has been normally vulcanized, and the strain gauge 11 is attached to the cut trace, followed by adhesive, rubber glue, The block cut by means such as re-vulcanization is re-adhered. In the latter case, the strain gauge 11 is embedded and vulcanized and molded, for example, in the step of attaching the rubber body G when forming a green tire. In the case of the former, there is an advantage that it can be embedded at an accurate position, and in the case of the latter, there is an advantage that sufficient embedding strength can be secured.
[0027]
When the strain gauge 11 is embedded, a lead wire (not shown) for measuring an electrical resistance value extending from the strain gauge 11 is wired, for example, by adhering along the tire cavity surface.
[0028]
Next, a tire deformation detection method for detecting deformation of the tire 1 by measuring the electrical resistance value of the strain gauge 11 will be described.
[0029]
First, the strain gauge 11 is connected to a bridge circuit or the like, for example, and a change in the electrical resistance value of the strain gauge 11 is amplified and measured. At this time, the measurement is performed with an interval of 0.001 seconds or less, preferably 0.0005 seconds or less. This is because the tire rotates once in about 0.11 seconds at a traveling speed of 60 km / h, for example, and the contact time is about 1/20, that is, the strain gauge 11 is about 0.0055 per rotation of the tire. Only ground for seconds. Therefore, by setting the measurement interval to 0.001 second or less, it is possible to measure the strain at a frequency of about 5.5 times or more during one contact and accurately and accurately detect the state of tire deformation. It can be done. However, if the measurement interval is too short, data processing may not be able to catch up, and therefore the lower limit is preferably 0.0001 seconds or more.
[0030]
In addition to grasping the slip situation of each tire, this detection result can obtain various information on the contact situation with the road surface, such as grasping the change of the load acting on each tire from the size of the tire deformation, For various safety control systems of automobiles, the control can be speeded up and highly accurate.
[0031]
In actual use, the amplified output from the strain gauge 11 is transmitted to, for example, a control system of the safety control system on the vehicle body side by wireless transmission using a transponder or the like. You may transmit by wired transmission. In the case of wireless transmission, the signal can be digitized and transmitted, or the output voltage can be converted into a frequency, and after transmission, the corresponding voltage signal can be converted again.
[0032]
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.
[0033]
【Example】
A tire having the tire structure shown in FIG. 1 and a strain gauge embedded in the tread central region Rc and the depth range Y is prototyped, and the tire runs on a drum at a speed (60 km / h) and a load (3.0 kN). The deformation of the tire at the time of being detected is detected by measuring the electric resistance value of the strain gauge, and the results are shown in FIGS. 4 (A) and 4 (B).
[0034]
As a strain gauge, a copper / nickel alloy foil low strain type foil gauge (manufactured by Kyowa Denki Co., Ltd .; KFG-03-120-C1-11) is used. As shown conceptually in FIG. Measurement was performed using a signal conditioner 31 and an oscilloscope 32. The measurement interval is 0.0005 seconds. FIGS. 4A and 4B show the measurement of radial distortion and circumferential distortion, respectively.
[0035]
4A and 4B, in the “distortion-time” curve, the time ta at the peak of the distortion is substantially the same, and the width W of the distortion is also substantially the same. It can also be confirmed that the deformation of the tire can be reliably detected.
[0036]
【The invention's effect】
The present invention as the Jo, inside the Toreddogo beam forming a tire outer skin, since the embedded strain gauges for detecting the distortion of the rubber, to seize contact situation of the road surface of the tire quickly and accurately Can contribute greatly to the safety control of automobiles.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a tire according to an embodiment of the present invention.
FIGS. 2A and 2B are a plan view for explaining a buried position of a strain gauge and a cross-sectional view taken along the line II in FIG.
FIGS. 3A to 3C are perspective views illustrating an embedded state of a strain gauge.
4A and 4B are measurement results when tire deformation is measured by a strain gauge. FIG.
FIG. 5 is a diagram conceptually showing an experimental apparatus for measurement.
FIG. 6 is a diagram illustrating the technical background of the present invention.
[Explanation of symbols]
2 Tread 2G Tread rubber 3 Side wall portion 3G Side wall rubber 4 Bead portion 4G Bead rubber 5 Bead core 6 Carcass 10 Tire structure 11 Strain gauge 12 Longitudinal main groove 13 Tread groove 14 Land portion C Tire equator Rc Tread central region Y Depth range

Claims (2)

A rubber body made of the tread rubber of the tread portion is arranged outside the tire structure including a carcass extending from the tread portion to the side wall portion to the bead core of the bead portion, and the rubber body is placed inside the tread rubber. A strain gauge that detects the strain of
And this tread rubber has a land part which consists of a block or a rib sectioned using a tread groove including a vertical main groove extending in the tire circumferential direction,
The strain gauge has a depth range in which the distance H in the tire radial direction from the bottom surface of the land portion and the longitudinal main groove is 1.6 mm or less,
Moreover, the tire axial distance L from the tire equator is a tread center region that is 0.25 times or less of the tread width TW ,
A pneumatic tire for an automobile, wherein the number of the tires is 4 or more and 20 or less, and two are not present in the same ground plane . An automotive tire deformation detection method for detecting deformation of a tire by measuring an electric resistance value of a strain gauge of the pneumatic tire for an automobile according to claim 1.

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