JP5470215B2 - Tire for measuring internal temperature of tire and measuring method thereof - Google Patents

Description

  The present invention relates to a tire for measuring internal temperature of a tire, which includes a pair of beads, a pair of sidewalls, a pair of shoulders, and a tread, and includes a thermocouple embedded so as to extend in the tire radial direction. Is. More specifically, by making the shape of the thermocouple spiral from the side of the tire, it is possible to measure the temperature inside the tire at a desired position, and against bending deformation due to load on the tire. The present invention relates to a tire for measuring a tire internal temperature and a tire internal temperature measuring method having excellent durability.

  Conventionally, as a method of measuring the temperature inside the running tire, for example, when it is desired to measure the temperature of the belt portion, a hole is made in the groove bottom of the vulcanized tire and a thermocouple terminal is embedded on the belt A method of pulling out from the shoulder portion to the sidewall portion while fixing the other terminal of the thermocouple in the groove of the tread portion is performed. However, this method requires a great deal of work to embed the thermocouple terminal on the belt, and it is difficult to position the thermocouple terminal at the position to be measured. In addition, the tape and adhesive for fixing the thermocouple in the tread groove are peeled off during running, and the thermocouple hits the road surface or the fender of the vehicle and breaks.

  On the other hand, in Patent Document 1, at a stage during the tire molding process before vulcanization (at the time of green tire molding), temperature measurement is possible at a desired position from the tread portion to the shoulder portion of the reinforcing layer. It has been proposed in advance that a temperature measuring unit of a thermocouple is arranged between radial arrangement carcass ply cords.

JP 2003-306015 A

  As described above, in the configuration of Patent Document 1, the internal temperature of the tire at a desired position can be measured. On the other hand, the thermocouple is parallel to the radial ply cord and is positioned immediately below the tire load when rolling the tire load. Since the tire is arranged in the tire radial direction parallel to the direction in which the tire bends, when a load is applied to the tire, the thermocouple that extends to the bead portion side, particularly greatly bent (bent) directly under the load There was a tendency for the thermocouple portion located in the deforming shoulder portion to break early.

  Accordingly, an object of the present invention is to provide a tire for measuring the temperature inside the tire and a method for measuring the temperature inside the tire, which can measure the temperature inside the tire at a desired position and has excellent durability.

As a result of extensive research by the inventors, the cause of the breakage of the thermocouple is that the structure of the thermocouple is a metal single wire or a stranded wire twisted with a single wire, which is vulnerable to repeated bending deformation of the tire. I found it.
Therefore, in order to achieve the above object, the inventors greatly shifted the thermocouple extension direction with respect to the direction in which the tire bends at the position immediately below the load, thereby reducing the distortion of the thermocouple when the tire is deformed. The present invention has been completed with the idea that the durability of the thermocouple can be improved.

That is, the gist of the present invention is as follows.
(1) A pneumatic tire comprising a pair of beads, a pair of sidewalls, a pair of shoulders and a tread, and comprising a thermocouple embedded so as to extend in the tire radial direction,
The thermocouple has a first terminal on the temperature measuring side arranged on the tread side, and a second terminal drawn out from the outer surface of the tire on the bead side, and the extending shape of the thermocouple is from the side of the tire A tire for measuring a tire internal temperature, wherein the tire has a spiral shape from the second terminal toward the first terminal through a thermocouple.

  (2) The tire internal temperature measuring tire according to (1), wherein the extending direction of the thermocouple is an angle of 10 ° to 45 ° with respect to the tire circumferential direction at least in a shoulder portion. .

  (3) The above-mentioned (1) or (2), wherein the position at which the second terminal of the thermocouple is pulled out from the outer surface of the tire is in a region of 0 to 20 mm from the rim flange apex position outward in the tire radial direction. The tire for measuring the internal temperature of the tire according to 1.

  (4) The rising angle of the thermocouple from the first terminal located immediately below the load of the tire to which a predetermined air pressure and load is applied is seen through the thermocouple from the side of the tire, and the traveling direction of the tire on the road surface The tire for measuring a tire internal temperature according to any one of (1) to (3), wherein the tire has an obtuse angle.

  (5) A tire internal temperature measurement method for measuring a tire internal temperature during traveling using the tire internal temperature measurement tire according to any one of (1) to (4) above.

  According to the present invention, the temperature inside the tire can be measured at a desired position, and the extending direction of the thermocouple is greatly deviated from the direction in which the tire bends at the position immediately below the load. By making the shape look spiral from the side of the tire, it is possible to provide a tire for measuring the inner temperature of the ear with excellent durability. Further, it is possible to provide a tire internal temperature measuring method using this.

FIG. 3 is a cross-sectional view in the width direction of the tire for measuring the temperature inside the tire according to the present invention, and the thermocouple is shown together in one cross section in the tire width direction for convenience of explanation. FIG. 2 is a partial development view showing the arrangement of thermocouples inside the tire of FIG. 1. FIG. 2 is a perspective view of the thermocouple of the tire of FIG. 1 from the side of the tire, where (a) shows that the rising angle of the thermocouple from the first terminal located immediately below the load of the tire is in the traveling direction of the tire on the road surface. On the other hand, it is a figure when it is an obtuse angle, (b) has shown the figure when the 1st terminal is going to enter into a ground area | region. The tire thermocouple of FIG. 1 is in a positional relationship opposite to that in FIG. 3A with respect to the tire traveling direction, and the rising angle of the thermocouple from the first terminal located immediately below the load of the tire is on the road surface. It is the figure which saw through the thermocouple in case it is an acute angle with respect to the advancing direction of the tire from the tire side surface. It is the figure which plotted the result of the Example.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 shows a cross section in the tire width direction of a tire for measuring a tire internal temperature (hereinafter referred to as “invention tire”) according to the present invention.

  As shown in FIG. 1, the tire according to this embodiment includes a tread portion 1 that forms a tread surface of the tire, and a pair of sidewalls that are connected to both ends of the tread portion 1 in the tire width direction via shoulder portions 2, 2. Parts 3, 3 and a pair of bead parts 4, 4 that are located on the inner side in the tire radial direction of the pair of sidewall parts 3, 3 and are attached to the wheel rim, and further, a pair of these bead parts 4, 4 A carcass 6 that is locked to the bead cores 5 and 5 embedded therein and extends in a toroid shape over the bead portions 4 and 4, the sidewall portions 3 and 3, the shoulder portions 2 and 2, and the tread portion 1, and a crown of the carcass 6 A radial tire having a conventional tire structure having a belt layer 7 arranged on the outer side in the tire radial direction.

  The belt layer 7 is formed by laminating at least two belt plies formed of a plurality of belt cords arranged in parallel and inclined in parallel to the tire circumferential direction, and in FIG. 1, two belt plies 7a and 7b are laminated. These belt plies 7a and 7b are laminated in the tire radial direction so that the belt cords cross each other across the tire equatorial plane.

  Further, a cap layer 8 is laminated on the outer side of the belt layer 7 in the tire radial direction, and a layer layer 9 is laminated so as to cover the ends of the belt layer 7 and the cap layer 8 in the tire width direction. A thermocouple 10 is embedded between the belt layer 7 and the tread (on the cap layer 8 in FIG. 1). The thermocouple 10 includes a first terminal 10a disposed on the tread portion 1 side at a position where temperature is desired to be measured, and a second terminal 10b extending from the first terminal 10a and drawn out to the bead portion 4 side.

  FIG. 2 shown next is a cap in which the thermocouple 10 is embedded in the tire (the tread rubber is removed to show the cord arrangement relationship between the cap layer 8, the layer layer 9, the belt layer 7 and the carcass layer 6). It is the partial expanded view which showed the layer 8 in detail. In FIG. 2, C indicates a tire equatorial plane, a double arrow direction A (vertical direction shown in FIG. 2) indicates the tire circumferential direction, and a double arrow direction B (horizontal direction shown in FIG. 2) indicates the tire width direction. .

  The first terminal 10a on the temperature measurement side which is one end of the thermocouple 10 is disposed and fixed at a position where it is desired to measure the internal temperature of the tire during load rolling. In the example shown in FIG. 2, the first terminal 10 a is fixed to the point P on the cap layer 8 so that the internal temperature at the point P on the tread portion 1 side can be measured.

Here, as shown in FIG. 1, since the tread surface of the tire is formed in a crown shape as seen in the cross section in the tire width direction, the tire has a thermocouple 10 arranged along the tire shape. However, bending will occur. That is, the thermocouple 10 disposed from the tread portion 1 side to the bead portion 4 side is compressed on the inner side in the tire radial direction and stretched on the outer side in the radial direction, so that the entire thermocouple 10 is distorted. Ten breaks may occur.
The thermocouple is a single metal wire or a twisted wire twisted from a single wire, and the outer diameter of the thermocouple is D (mm), and the radius of curvature of the thermocouple arrangement (extended) shape is R (mm). The maximum strain εmax of the thermocouple bent along the tire shape is
[Formula 1]
εmax = D / 2R
It can be expressed as Therefore, in order to suppress the occurrence of breakage of the thermocouple, it is effective to reduce the maximum strain value εmax of the thermocouple, which reduces the value of the radius of curvature R of the thermocouple arrangement shape. This is possible.

  Therefore, in the tire of the present invention, after fixing the first terminal 10a, which is the temperature measuring portion of the thermocouple 10, to the tread portion 1 side, the second terminal 10b, which is the other terminal of the thermocouple 10, is connected to the bead portion. When the thermocouple 10 is extended by being arranged on the side 4, the thermocouple 10 is arranged so that an angle α formed between the thermocouple 10 and the tire circumferential direction (arrow direction A) becomes an acute angle. That is, as shown in FIG. 2, which thermocouple 10 extends from the first terminal 10 a fixed at the temperature measurement position P to the second terminal 10 b on the bead portion 4 side toward the outer side in the tire width direction. Also in the region, the thermocouple 10 is arranged so as to be largely deviated from the direction in which the tire bends immediately below the tire load.

  3 and 4 show the above configuration from another viewpoint. Specifically, as described in FIG. 2, the thermocouple is extended so as to form an acute angle with respect to the tire circumferential direction. The figure at the time of seeing through 10 from the tire side is shown. As is clear from this figure, when the thermocouple is seen through from the side of the tire, the thermocouple 10 of the tire of the present invention extends in a spiral shape from the first terminal 10a to the second terminal 10b. doing. In FIGS. 3 and 4, for the sake of simplicity of explanation, the thermocouple 10 is made to make one round on the tire so that the first terminal 10 a and the second terminal 10 b are substantially in the same position in the tire circumferential direction. However, it is not always necessary to draw such a shape. That is, when the angle α formed between the thermocouple 10 and the tire circumferential direction is relatively small, the above shape is obtained. When the angle α is relatively large, the thermocouple extends from the first terminal 10a to the second terminal 10b. Since 10 becomes short, it does not have a shape that goes around the tire. Accordingly, the spiral shape in the present invention includes both cases.

  Thus, if the thermocouple 10 is arranged so as to have a spiral shape when the thermocouple is seen through from the side surface of the tire, the curvature radius R of the arrangement shape of the thermocouple of Formula 1 is increased, and the distortion of the thermocouple is increased. Can be reduced. As a result, it becomes possible to effectively suppress the occurrence of breakage of the thermocouple.

  In addition, although the example shown in FIGS. 2-4 has shown the case where the angle with respect to the tire circumferential direction of the thermocouple 10 extended toward the 2nd terminal 10b from the 1st terminal 10a is two different angles. The thermocouple 10 may be extended so that the angle with respect to the tire circumferential direction is gradually different (for example, gradually increasing or decreasing).

In order to effectively suppress the occurrence of breakage of the thermocouple, at least in the shoulder portion 2, the thermocouple 10 is placed at an angle of 10 to 45 ° with respect to the tire circumferential direction (the angle α shown in FIG. 2 is 10 to 45). It is more preferable to arrange them at °).
Here, the “shoulder portion 2” in the present invention refers to a region from the end portion of the portion where the tire deformation is greatest when the tire is loaded to the tire maximum width direction position WP. More specifically, in the case of a radial tire as in this embodiment, the “shoulder portion 2” referred to in the present invention is the end portion of the outermost layer of the cap layer, the layer layer, and the belt layer. In the example illustrated in FIG. 1, the region from the layer end LE of the layer layer 9 in which the thermocouple 10 is embedded to the tire maximum width direction position WP is referred to. The tire maximum width direction position WP is an industry standard effective in the region where the tire is produced or used, for example, The Tire and Rim Association Inc. in the United States. Assembling tires to the standard rims of the standard sizes described in "Standard Book" of the European Tire and Rim Technical Organization in Europe, "JATMA Year Book" of the Japan Automobile Association in Japan, It is a position (points WP and WP shown in FIG. 1) that is the outermost point in the tire width direction in a state where a predetermined load of the single wheel in the applied size and an air pressure corresponding to the predetermined load are applied.

The above description is based on the case of a radial tire as shown in FIG. 1, but the tire of the present invention may be either a radial tire or a bias tire.
In the case of a bias tire, the “shoulder portion 2” in the present invention refers to a region from the ground contact end to the tire maximum width direction position WP where the tire deformation is greatest.
Furthermore, the present invention can be applied not only to measuring the internal temperature of a radial tire and a bias tire under normal use conditions, but also to measuring the temperature of a reinforcing rubber during run flat running of the run flat tire.

As described above, as shown in FIG. 1, the tread surface of the tire is formed into a crown shape as seen in the cross section in the tire width direction, and the tire is subjected to centrifugal force and rim during cornering when rolling the tire. The tire bends greatly due to the load, and the crown-shaped tire is forced against the flat road surface to become straight, and conversely, when it leaves the road surface, it returns to its original shape. The deformation is repeated. And the deformation | transformation of this tire is remarkable in the shoulder part with the largest bending. Therefore, the thermocouple arranged along the shape of the tire is most easily broken at the shoulder portion where the large deformation occurs. That is, in the case of a radial tire, the rigidity of the layer is high and the bending deformation of the outer portion in the tire width direction is the largest, so the end of the outermost layer of the cap layer, the layer layer, and the belt layer. In the region from the center to the tire maximum width direction position WP, in the case of a bias tire, the bending deformation is the largest, and in the region from the ground contact end to the tire maximum width direction position WP, each is most likely to break.
Accordingly, among the thermocouples 10 extending from the first terminal 10a toward the second terminal 10b, the thermocouple 10 of the formula 1 is arranged in the shoulder portion 2 where the thermocouple 10 is most easily deformed and easily broken. By increasing the radius of curvature R, it is possible to more effectively suppress the occurrence of breakage of the thermocouple.

At this time, in the region where the extension angle α of the thermocouple 10 with respect to the tire circumferential direction is relatively small, the radius of curvature R of the thermocouple arrangement shape is increased, and the durability against breakage of the thermocouple is effectively improved. Can be made. However, if the extending angle α of the thermocouple with respect to the tire circumferential direction is less than 10 °, the total length of the thermocouple for extending to the bead portion side becomes too long, and the working efficiency may deteriorate instead. . Moreover, when a thermocouple is affixed to the cylindrical carcass before expansion, there is a possibility that expansion necessary for molding a green tire may be hindered. Therefore, the angle α of the thermocouple with respect to the tire circumferential direction is preferably 10 ° or more.
On the other hand, in the region where the extending angle α of the thermocouple with respect to the tire circumferential direction is relatively large, the length of the thermocouple is shortened, so that the working efficiency of embedding the thermocouple can be improved. However, if the extending angle α of the thermocouple with respect to the tire circumferential direction is greater than 45 °, the radius of curvature R of the thermocouple arrangement shape becomes small, and the thermocouple is likely to break. Therefore, by setting the angle α of the thermocouple with respect to the tire circumferential direction to be 45 ° or less, it is possible to secure good embedding work efficiency while suppressing the occurrence of breakage of the thermocouple.

In addition, the thermocouple 10 should just be arrange | positioned at an angle of 10-45 degrees with respect to the circumferential direction at least in the shoulder part 2, and you may make it arrange | position at a larger angle in another tire part. This is because by arranging the tires at other tire portions at a relatively large angle with respect to the circumferential direction, the total length of the thermocouple can be shortened and the working efficiency can be increased.
In the shoulder portion 2 as well, the extension angle α of the thermocouple 10 does not need to be constant, and an optimal extension angle can be appropriately selected for each region to exert the above-described effects.

Further, the second terminal 10b, which is the other end of the thermocouple 10 extending from the first terminal 10a toward the bead portion 4, has a tire outer surface in a region of 0 to 20 mm from the rim flange apex position T to the outer side in the tire radial direction. It is preferable to be pulled out.
When the second terminal 10b is pulled out from the rim flange apex position T to the tire outer surface in a region larger than 20 mm outward in the tire radial direction, the thermocouple hits the road surface or the vehicle fender during rolling of the tire load, and the thermocouple breaks. This is because there is a risk of it.

Further, the rising angle (extending direction) of the thermocouple 10 from the first terminal 10a to the second terminal 10b at the position directly under the load of the tire to which a predetermined air pressure and load is applied is seen through the thermocouple 10 from the side of the tire. In this case, as shown in FIG. 3A, it is more preferable that the obtuse angle is obtained with respect to the tire traveling direction.
Here, the “traveling direction of the tire” referred to in the present invention refers to a direction in which the axial center Q of the tire travels when the vehicle is driven forward. Accordingly, in the example shown in FIG. 3A, with the first terminal 10a as the apex, the road surface on the right side of the page from the first terminal 10a and the rising line of the thermocouple 10 extending from the first terminal 10a to the left side of the page are The case where the angle β formed is an obtuse angle.
In this manner, the thermocouple 10 is seen through from the side of the tire, and the angle β formed by the thermocouple 10 extending from the first terminal 10a directly below the tire load and the road surface in the tire traveling direction is an obtuse angle. In other words (in other words, in the partially developed view, when the angle formed by the rotation direction of the tire and the thermocouple 10 is an acute angle), when the thermocouple 10 enters the grounding region by the rotation of the tire, Since the incident angle with respect to the road surface becomes small as shown in FIG. 3B, the load on the thermocouple 10 is reduced. Therefore, the occurrence of breakage of the thermocouple can be suppressed more effectively than when the angle β is an acute angle as shown in FIG.

  The present invention is applicable not only to measuring the internal temperature of a radial tire and a bias tire under normal use conditions, but also to measuring the temperature of a reinforcing rubber during run flat running of a run flat tire.

  In the above-described embodiment, the thermocouple is used as the temperature measuring unit. However, the present invention is not limited to the thermocouple. For example, a sensor having a metal conductor may be used.

Next, in order to confirm the effect of the invention, tire internal temperature measurement tires (Example tires 1 to 8) included in the scope of the present invention and tire internal temperature measurement tires (comparative tires) according to the prior art are prepared. Each tire was subjected to load rolling with a drum testing machine. In the example tire and the comparative example tire, the thermocouple has a first terminal disposed immediately above the belt layer and extends outward in the tire radial direction, and the second terminal is positioned 10 mm from the rim flange apex to the tire radial direction outer side. Pulled out.
The temperature data measured by the thermocouple is obtained by connecting the second terminal of the thermocouple to the rotation side terminal of the slip ring attached to the tire rotation shaft, and connecting the fixed terminal of the slip ring and the data logger with a compensating conductor. Obtained.

The tire size used for the test is 225 / 65R17, and the thermocouple is a T-type in which seven conductors (copper, constantan) of φ0.1 mm are twisted. The test is an accelerated test for durability evaluation. The drum test conditions were a rim width of 6.5 inches (165.1 mm), a tire internal pressure of 240 kPa, a load load of 850 kgf (8335.6525 N), and a speed of 200 km / h. .
The results are shown in Table 1 below. The angle formed by the tire traveling direction and the thermocouple is an angle when the state where the thermocouple comes directly under the load is seen through from the side surface of the tire.

From the results of Table 1, the angle of the thermocouple with respect to the tire circumferential direction is not vertical as in the example tires (when the thermocouple is seen through from the side of the tire, the shape of the thermocouple is spiral), the tire circumference As it approached in parallel with the direction, it was found that the tire for measuring the internal temperature of the tire was superior in durability to the comparative example tire.
Further, as apparent from FIG. 5 in which Table 1 is plotted, the thermocouple extending direction is shifted from the state where the angle of the thermocouple to the tire circumferential direction is 45 ° so as to approach the tire circumferential direction to 10 °. It was found that the measurement time was significantly longer when in the state.
Furthermore, when the thermocouple is seen directly under the load when seen through the thermocouple from the side of the tire, the angle between the tire traveling direction and the thermocouple is an obtuse angle than the case where the angle is an acute angle. It was also found that the durability was excellent. When the measurable time of 3.0 minutes or more is good, when the angle between the tire traveling direction and the thermocouple is an obtuse angle, when the angle with respect to the tire circumferential direction is 10 to 45 °, the tire progression It was found that when the angle between the direction and the thermocouple is an acute angle, the angle is 10 to 30 ° with respect to the tire circumferential direction.

  According to the present invention, the temperature inside the tire can be measured at a desired position, and the shape of the thermocouple is seen through the tire from the side of the tire so that the radius of curvature of the arrangement shape of the thermocouple becomes large. Thus, it is possible to provide a tire for measuring the temperature inside the tire having excellent durability.

DESCRIPTION OF SYMBOLS 1 Tread part 2 Shoulder part 3 Side wall part 4 Bead part 5 Bead core 6 Carcass 7 Belt layer 7a, 7b Belt ply 8 Cap layer 9 Layer layer 10 Thermocouple 10a First terminal of thermocouple 10b Second terminal of thermocouple T rim Flange vertex position LE Layer edge WP Tire maximum width direction position

Claims (5)

A pneumatic tire comprising a pair of beads, a pair of sidewalls, a pair of shoulders and a tread, and comprising a thermocouple embedded so as to extend in the tire radial direction,
The thermocouple has a first terminal on the temperature measuring side arranged on the tread side, and a second terminal drawn out from the outer surface of the tire on the bead side, and the extending shape of the thermocouple is from the side of the tire A tire for measuring a tire internal temperature, wherein the tire has a spiral shape from the second terminal toward the first terminal through a thermocouple.   2. The tire internal temperature measuring tire according to claim 1, wherein the extending direction of the thermocouple is an angle of 10 ° to 45 ° with respect to the tire circumferential direction at least in a shoulder portion.   The tire internal temperature according to claim 1 or 2, wherein the position where the second terminal of the thermocouple is pulled out from the outer surface of the tire is in a region of 0 to 20 mm from the rim flange apex position to the outer side in the tire radial direction. Tire for measurement.   The rising angle of the thermocouple from the first terminal at a position immediately below the load of the tire to which a predetermined air pressure and load is applied is seen through the thermocouple from the side of the tire, and with respect to the traveling direction of the tire on the road surface. The tire for measuring the temperature inside the tire according to any one of claims 1 to 3, wherein the tire has an obtuse angle.   The tire internal temperature measurement method which measures the tire internal temperature in driving | running | working using the tire for tire internal temperature measurement as described in any one of Claims 1-4.

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