JP2014213725A - Aircraft tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aircraft tire capable of suppressing generation of heat from a land part.SOLUTION: An aircraft tire 10 includes a land part 18 which is provided in a tread part 12 and which is partitioned with a plurality of circumferential grooves 14 elongated in a tire circumferential direction TW, and a wall surface 18A of the land part 18, in which a plurality of recesses 24 are formed at intervals in a tire circumferential direction TC and in which the recess 24 formed on the one wall surface 18A and the recess 24 formed on the other wall surface 18A are formed in different positions in the tire circumferential direction TC.

Description

  The present invention relates to aircraft tires mainly used for passenger aircraft and the like.

  A belt layer extending in the tire circumferential direction between the tread rubber and the carcass, a belt reinforcing layer inclined with respect to the tire circumferential direction, and a protective belt layer extending in a wave shape in the tire circumferential direction on the outer peripheral side of the belt reinforcing layer (For example, patent document 1).

JP2012-153310A

  In aircraft tires used under heavy loads, such as aircraft tires described in Patent Document 1, the end of the land portion that is in contact with the road surface during takeoff or landing is pushed and deformed, Due to the deformation of the land portion, shear strain may occur and the end portion of the land portion may generate heat.

  In view of the above facts, an object of the present invention is to provide an aircraft tire that can suppress heat generation in the land.

  The aircraft tire according to claim 1 is a land portion provided in a tread portion and partitioned by a plurality of circumferential grooves extending in a tire circumferential direction, and a wall surface of the land portion, the tire tire being spaced apart in the tire circumferential direction. A plurality of recesses are formed, and the wall surface of the land portion in which the recesses formed on one wall surface and the recesses formed on the other wall surface are formed at different positions in the tire circumferential direction, and Have

  According to the aircraft tire of the first aspect, the both wall surfaces of the land portion defined by the circumferential grooves are provided with a plurality of recesses at intervals in the tire circumferential direction. Thereby, since the surface area of a land part increases and the contact area with air increases, the cooling effect of a tire can be heightened.

  Moreover, the tension | tensile_strength which acts on a land part is relieve | moderated by forming the recessed part in the wall surface of a land part. Thereby, the shear distortion which acts on the edge part of a land part is reduced, and heat_generation | fever can be suppressed. Furthermore, since the concave portion formed on one wall surface of the land portion and the concave portion formed on the other wall surface are formed at different positions in the tire circumferential direction, the concave portion is formed at the same position in the tire circumferential direction. Compared to the case, the land portion is evenly cooled in the tire circumferential direction, and the temperature of the land portion can be suppressed from varying in the tire circumferential direction.

  The aircraft tire according to claim 2 is the aircraft tire according to claim 1, wherein the tread portion includes a plurality of land portions having different lengths in the tire width direction, and the tire width direction length. The recesses formed in the wall surface of the land portion with a long length are narrower in the tire circumferential direction than the recesses formed in the wall surface of the land portion with a short length in the tire width direction.

  The land portion having a long length in the tire width direction is less likely to dissipate heat than the land portion having a short length in the tire width direction, and the temperature of the land portion is unlikely to decrease. For this reason, the temperature difference between land parts can be made small by narrowing the space | interval of the recessed part of a land part with a long length of a tire width direction from the space | interval of the recessed part of a land part with a short length of a tire width direction.

  An aircraft tire according to a third aspect is the aircraft tire according to the first or second aspect, wherein the concave portion is opened in a tread surface of the land portion.

  According to the aircraft tire of the third aspect, since the recess is opened in the tread surface of the land portion that contacts the road surface, the end portion of the land portion is divided in the tire circumferential direction. Thereby, a shear distortion can be reduced compared with the case where a recessed part is not opening to the tread of a land part.

  The aircraft tire according to claim 4 is the aircraft tire according to any one of claims 1 to 3, wherein the concave portion is formed by cutting a wall surface of the land portion obliquely with respect to a tire width direction. Has been.

  According to the aircraft tire of the fourth aspect, since the concave portion is formed by cutting the wall surface of the land portion obliquely with respect to the tire width direction, the end portion of the land portion is deformed to the tire rotation direction side. It becomes easy and the shear strain which acts on the edge part of a land part can be reduced.

  Since this invention set it as said structure, it can suppress the heat_generation | fever of the land part of an aircraft tire.

It is a development view showing a tread pattern of an aircraft tire according to a first embodiment of the present invention. It is a principal part expansion perspective view which shows the recessed part which concerns on 1st Embodiment of this invention. It is an expanded view which shows the tread pattern of the aircraft tire which concerns on 2nd Embodiment of this invention. (A) is a principal part enlarged plan view which shows the recessed part which concerns on 2nd Embodiment of this invention, (B) is sectional drawing cut | disconnected by the 4B-4B line | wire of FIG. 4 (A).

(First embodiment)
An aircraft tire 10 (hereinafter referred to as a tire 10) according to a first embodiment of the present invention will be described with reference to the drawings. In the drawing, an arrow TW indicates a direction parallel to the rotation axis of the tire 10 (hereinafter referred to as “tire width direction” as appropriate), and an arrow TC indicates a circumferential direction of a circle centering on the rotation axis of the tire 10. (Hereinafter referred to as “tire circumferential direction” as appropriate). In the drawing, CL indicates an equatorial plane (a plane passing through the center in the width direction of the tire and parallel to the tire radial direction). Furthermore, a direction perpendicular to the rotation axis of the tire 10 is described as a tire radial direction.

  A tire 10 shown in FIG. 1 is a tire used for an aircraft such as a passenger plane, and includes a tread portion 12 formed of a tread rubber layer. The internal structure inside the tread portion 12 is the same as the well-known internal structure of an aircraft tire. From the tread portion 12 side to the inside in the tire radial direction, a cut protector layer, a belt protective layer, a spiral belt layer, a carcass (not shown) are provided. It is composed of layers.

  The tread portion 12 is formed with a plurality of circumferential grooves extending in the tire circumferential direction. Specifically, a total of a pair of first circumferential grooves 14 formed across the equator plane CL and a pair of second circumferential grooves 16 formed on the outer side in the tire radial direction from the first circumferential grooves 14. Four circumferential grooves are formed. The first circumferential groove 14 and the second circumferential groove 16 are formed with the same groove width and the same groove depth, and the tread portion 12 is axisymmetric with respect to the equator plane CL.

  In the present embodiment, as an example, a total of four circumferential grooves including two first circumferential grooves 14 and two second circumferential grooves 16 are formed at intervals in the tire width direction. However, the present invention is not limited to this, and for example, a pair of left and right third circumferential grooves may be formed in the tire width direction from the second circumferential groove 16, and conversely, the number of tire circumferential grooves is reduced to a pair. Only the first circumferential groove 14 may be formed. Further, a circumferential main groove extending in the tire circumferential direction along the equator plane CL may be formed, or asymmetric with respect to the equator plane CL. Further, the first circumferential groove 14 and the second circumferential groove 16 may be formed with different groove widths or different groove depths.

  The tread portion 12 is partitioned by a pair of first circumferential grooves 14 and is partitioned by a first land portion 18 located at the center in the tire width direction, and a first circumferential groove 14 and a second circumferential groove 16. And a second land portion 20 on the outer side in the tire width direction from the first land portion 18. A shoulder portion 22 is provided on the outer side in the tire width direction from the second circumferential groove 16.

  Here, on both wall surfaces 18A of the first land portion 18 in the tire width direction, cutout portions 24 as concave portions are formed. A plurality of notches 24 are formed at intervals in the tire circumferential direction. In the present embodiment, as an example, 24 notches 24 are formed at equal intervals in the tire circumferential direction (in FIG. 1). Since only a part of the first land portion 18 is shown, 13 notch portions 24 are shown at both ends of the first land portion 18). However, the present invention is not limited to this, and the notches 24 may be formed at unequal intervals. Here, the notches 24 are formed at different positions in the tire circumferential direction, and in the present embodiment, the notches 24 formed on the one wall surface 18A and the notches formed on the other wall surface 18A. The notch portions 24 are formed alternately in the tire circumferential direction.

  As shown in FIG. 2, the notch 24 is formed by notching the wall surface 18 </ b> A of the first land portion 18 in the tire width direction. The notch 24 is formed in the tire radial direction from the groove bottom of the first circumferential groove 14 to the surface (tread) of the first land 18 and is open to the surface (tread) of the first land 18. doing. In the present embodiment, the opening 24A of the notch 24 has a substantially triangular shape that narrows from the end of the first land 18 toward the center in plan view, but is not limited thereto. For example, the opening 24A may be formed in a semicircular shape or an elliptical shape.

  As shown in FIG. 1, notches 26 are formed at both ends in the tire width direction of the second land portion 20 at intervals in the tire circumferential direction. The notches 26 are formed in the same shape as the notches 24 formed in the first land portion 18, and in the present embodiment, as an example, eight notches are formed at equal intervals in the tire circumferential direction (see FIG. In FIG. 1, only a part of the second land portion 20 is illustrated, and therefore two to three notches 26 are illustrated at both ends of the second land portion 20).

  Here, the notches 26 are formed at different positions in the tire circumferential direction. Here, the different positions in the tire circumferential direction indicate positions where the notches 26 do not overlap each other when the notches 26 formed in the second land portion 20 are projected in the tire width direction. Yes, the notch portion 24 formed in the first land portion 18 and the notch portion 26 formed in the second land portion 20 may be formed at the same position in the tire circumferential direction. Moreover, the notch part 24 formed in the 1st land part 18 and the notch part 28 formed in the shoulder part 22 may be formed in the same position in the tire circumferential direction.

  A notch portion 28 is formed in the wall surface 22A of the shoulder portion 22 on the second circumferential groove 16 side. The shape of the notch portion 28 is the same shape as the notch portion 24 of the first land portion 18 and the notch portion 26 of the second land portion 20. In the present embodiment, as an example, the notch portion 28 is equally spaced in the tire circumferential direction. Twelve notches 28 are formed (in FIG. 1, only a part of the shoulder 22 is shown, so that six notches 28 are shown).

(Function)
Next, the operation of the tire 10 according to this embodiment will be described. In the tire 10 of the present embodiment, the notch 24 formed on the wall surface 18A of the first land portion 18, the wall surface 20A on the first circumferential groove 14 side of the second land portion 20, and the second circumferential groove 16 side. The first land portion 18, the second land portion 20, and the notch portion 26 formed on the wall surface 20 B of the shoulder portion 22 and the notch portion 28 formed on the wall surface 22 A on the second circumferential groove 16 side of the shoulder portion 22, The surface area of the shoulder portion 22 is increased. Thereby, the contact area with air increases and the cooling effect of the tire 10 can be heightened.

  Further, the tension acting on the first land portion 18, the second land portion 20, and the shoulder portion 22 is eased by the notch portion 24, the notch portion 26, and the notch portion 28. That is, both end portions of the first land portion 18 are easily deformed in the tire circumferential direction side as compared with a state where the notch portion 24 is not formed. Thereby, the shear strain which acts on the edge part of the 1st land part 18 is reduced, and heat_generation | fever can be suppressed. The same applies to the second land portion 20 and the shoulder portion 22. Further, by reducing the tension, the wear amount of the tire 10 is reduced, and durability can be improved.

  Furthermore, since the notches 24 formed at both ends of the first land portion 18 are formed at different positions in the tire circumferential direction, temperature unevenness in the circumferential direction of the tire 10 can be suppressed. That is, when the notch 24 is formed at both ends of the first land portion 18 at the same position in the tire circumferential direction, the tire 10 is cooled only at the portion where the notch 24 is formed, and the temperature in the tire circumferential direction is increased. Unevenness may occur. For this reason, if the notches 24 are formed alternately in the tire circumferential direction as in the tire 10 of the present embodiment, it is possible to suppress the occurrence of temperature unevenness in the tire circumferential direction.

  In the present embodiment, the notch portion 24 is formed from the groove bottom of the first circumferential groove 14 to the surface (tread surface) of the first land portion 18, but is not limited thereto, and the first circumferential groove A notch portion 24 that does not open to the first land portion 18 by notching only the vicinity of the groove bottom 14 may be formed. However, when the notch portion 24 is opened on the surface (tread surface) of the first land portion 18, the tread surfaces at both ends of the first land portion 18 are divided in the tire circumferential direction, so that shear strain can be reduced. Further, if the notch depth h in the tire radial direction of the notch 24 is formed in the range of 0.5H ≦ h ≦ H with respect to the groove depth H of the first circumferential groove 14, the first land The effect of dividing the portion 18 in the tire circumferential direction can be further enhanced. The same applies to the notch 26 and the notch 28. In the present embodiment, as shown in FIG. 2, h = H.

  Further, in this embodiment, the notch width w in the tire width direction of the notch portion 24 is 0.5R ≦ w ≦ when the radius of curvature of the end portion of the first land portion 18 in the tire width direction is R. The apex angle θ when the cutout 24 is viewed in plan is 0 ° <θ ≦ 90 °. The effect of maintaining the rigidity of the first land portion 18 while increasing the surface area of the first land portion 18 by setting the notch width w and the apex angle θ of the notch portion 24 within the above range. Although the height can be increased, the notch 24 may be formed with a dimension outside the above range. The same applies to the notch 26 and the notch 28.

  In the present embodiment, the pitch p1 in the tire circumferential direction of the notch 24 formed on the wall surface 18A of the first land portion 18 is equal to the notch 26 formed on the wall surfaces 20A and 20B of the second land portion 20. In the tire circumferential direction, the pitch is narrower than the pitch p2 (see FIG. 1). Since the length W1 of the first land portion 18 in the tire width direction is longer than the length W2 of the second land portion 20 in the tire width direction, heat is likely to be generated inside the tire from the second land portion 20 and is not easily radiated. For this reason, by making the pitch p1 of the notches 24 narrower than the pitch p2 of the notches 26, the cooling effect of the first land portion 18 is enhanced and the temperature difference between the first land portion 18 and the second land portion 20 is increased. Can be reduced. That is, the temperature difference in the tire width direction of the tire 10 can be reduced.

(Test example)
In order to confirm the effect of the tire 10 according to the present embodiment, a total of four types of tires including three types of tires and a comparative example were prepared and tested. The tires of Examples and Comparative Examples used in the test will be described below. In addition, the tire size used for the test was 1400 × 530R23 40PR, and the internal pressure was set to a normal internal pressure (1500 kPa). Further, each tire is formed with a first circumferential groove and a second circumferential groove at the same position as the tire 10 of the first embodiment, and a notch having the same shape as the notch 24 is formed in the first land portion. did.
Example 1: Eight notches were formed at both ends of the first land portion.
Example 2: Twelve notches were formed at both ends of the first land portion.
Example 3: Twenty-four notches were formed at both ends of the first land portion.
Comparative example: Conventional tire with no notch formed.

  Test content: A take-off test was performed under the conditions defined in TSO-C62e, and the temperature at the end of the land was measured. The measured temperature was evaluated as a measure. As for the wear amount, the tire was rolled at 2 m / min, and the integrated value of the shear force and the slip amount at the end of the land at the time of rolling was calculated as wear energy, and this was evaluated as a wear measure. .

  As shown in the test results of Table 1, the cooling effect of the tires of Examples 1 to 3 in which the notch portion was formed was confirmed as compared with the tire of the comparative example in which the notch portion was not formed. It was also confirmed that the tire cooling effect was enhanced as the number of notches increased. However, a sufficient cooling effect can be obtained if there are 24 at each end of the land, so there is no need to increase the number of notches. Further, the amount of wear at the end of the land portion is reduced as the number of notches increases.

(Second Embodiment)
Next, an aircraft tire 50 (hereinafter referred to as a tire 50) according to a second embodiment of the present invention will be described. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIG. 3, the tire 50 according to the present embodiment includes a tread portion 12, and the tread portion 12 includes a first circumferential groove 14 and a second circumferential groove 16 at the same position as the first embodiment. Is formed.

  Notches 52L and 52R are formed in the wall surface 18A of the first land portion 18 defined by the first circumferential groove 14. The cutout portions 52L and the cutout portions 52R are alternately formed with a gap in the tire circumferential direction. In the present embodiment, as an example, the 24 cutout portions 52L and the cutout portions are equally spaced in the tire circumferential direction. A notch 52R is formed.

  Here, the notches 52L and 52R are formed by obliquely notching the wall surface 18A of the first land portion 18 with respect to the tire width direction. In the present embodiment, as an example, the notch portion 54L and the notch portion 54R are formed at angles opposite to each other in the tire width direction. That is, the notch 52L extends obliquely from the wall surface 18A toward the inside in the tire width direction at an angle to the lower side in the figure, and the notch 52R extends from the wall surface 18A toward the inside in the tire width direction. It extends obliquely at an angle toward the middle upper side.

  Cutout portions 54L and 54R are formed on the wall surfaces 20A at both ends of the second land portion 20 in the tire width direction. The cutout portion 54L on the left side in the drawing from the equator plane CL extends obliquely from the wall surface 20A of the second land portion 20 toward the center of the second land portion 20 at an angle toward the lower side in the drawing. The cutout portion 54R on the right side in the drawing from CL extends obliquely from the wall surface 20A toward the center of the second land portion 20 with an angle upward in the drawing.

  Notches 56L and 56R are formed in the wall surface 12A of the shoulder portion 22 on the second circumferential groove 16 side. The cutout portion 56L on the left side in the drawing from the equator plane CL extends obliquely from the wall surface 22A toward the outer side in the tire width direction at an angle downward in the drawing, and the cutout portion on the right side in the drawing from the equator plane CL. 56R extends obliquely from the wall surface 22A toward the outer side in the tire width direction with an angle upward in the drawing. In the present embodiment, the notches 52L, 52R, 54L, 54R, 56L, and 56R are all formed in the same shape, but are not limited thereto, and may be formed in different shapes. Further, the notches 52L, 54L, and 56L are formed at the same inclination angle with respect to the tire width direction, but may be different inclination angles. For example, the inclination angle may be set in accordance with the stress in the tire circumferential direction that acts on each land portion when contacting the road surface. The same applies to the notches 52R, 54R, and 56R.

  Here, as shown in FIG. 4, the notch 52 </ b> L is formed obliquely with respect to the depth direction (tire radial direction) of the first land portion 18. Specifically, as shown in FIG. 4B, the first land portion 58 extends obliquely from the surface (tread surface) 18B toward the inner side in the tire radial direction toward the lower side in the figure (the tire circumferential direction side). . Further, the cutout portion 52R extends obliquely from the surface (tread surface) 18B of the first land portion 18 toward the opposite side (upper side in the drawing) from the cutout portion 52L in the tire radial direction.

  According to the tire 50 of the present embodiment, when the first land portion 18 comes into contact with the road surface and both end portions of the first land portion 18 are expanded, the first land portion 18 is deformed and sheared in the tire circumferential direction side. Generation of distortion can be suppressed. Here, for example, when the tire 50 rotates on the upper side in FIG. 3, the first land portion 18, the second land portion 20, and the shoulder portion 22 on the right side in the drawing from the equator plane CL are closer to the tire circumferential direction. It becomes easy to deform. Further, when the tire 50 rotates in the opposite direction, the first land portion 18, the second land portion 20, and the shoulder portion 22 on the left side in the drawing from the equator plane CL are more easily deformed toward the tire circumferential direction. Thus, you may form the notch part opposite to a tire width direction.

  In the present embodiment, the inclining directions of the left notches 52L, 54L, and 56L in the drawing and the right notches 52R, 54R, and 56R in the drawing with the equator plane CL interposed therebetween are opposite directions. For example, the inclining directions of the notches 54L and 54R may be formed in opposite directions at both ends of the second land portion 20. Moreover, you may form all the notch parts in the same direction. In this case, the land portion can be easily deformed in only one direction by designating the rotation direction of the tire.

  Further, in the present embodiment, the cutout portion 52L extends obliquely with respect to the tire width direction and also extends obliquely with respect to the tire radial direction. It may be formed obliquely with respect to the direction and linearly formed in the tire radial direction, and conversely, it may be formed linearly with the tire width direction and obliquely formed with respect to the tire radial direction. Good. Furthermore, the inclination direction with respect to the tire width direction and the inclination direction with respect to the tire radial direction may be different directions.

  The first and second embodiments of the present invention have been described above, but the present invention is not limited to such embodiments, and can be implemented in various modes without departing from the spirit of the present invention. Of course. For example, a part of the notch portion 24 formed in the first land portion 18 of FIG. 1 may be cut obliquely with respect to the tire radial direction and mixed with the notch portion 24 parallel to the tire width direction.

10, 50: Aircraft tires, 14: First circumferential groove (circumferential groove), 16: Second circumferential groove (circumferential groove), 18: First land portion (land portion), 18A, 20A, 20B 22A: Wall surface 20: Second land portion (land portion) 24, 26, 28, 52L, 52R, 54L, 54R, 56L, 56R: Notch portion (recessed portion)

Claims (4)

A land portion provided in the tread portion and partitioned by a plurality of circumferential grooves extending in the tire circumferential direction;
A plurality of recesses are formed on the wall surface of the land portion at intervals in the tire circumferential direction, and the recesses formed on one wall surface and the recesses formed on the other wall surface are in the tire circumferential direction. And the wall surface of the land portion formed at different positions in
Aircraft tire having The tread portion includes a plurality of land portions having different lengths in the tire width direction,
The recess formed in the wall surface of the land portion having a long length in the tire width direction has an interval in the tire circumferential direction between the recess portions formed in the wall surface of the land portion having a short length in the tire width direction. The aircraft tire according to claim 1, which is narrow.   The aircraft tire according to claim 1 or 2, wherein the concave portion is opened in a tread surface of the land portion.   The aircraft tire according to any one of claims 1 to 3, wherein the concave portion is formed by cutting a wall surface of the land portion obliquely with respect to a tire width direction.

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