JP2006111088A - Pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of improving low heat build-up without deteriorating wear resistance. <P>SOLUTION: This pneumatic tire includes a main groove 1 formed along the circumferential direction of a tire in a tread 3. A plurality of bank-shaped projected parts 2 extended along a mold removing direction (the arrow A direction) is provided on at least one side face of the main groove 1.The projected parts 2 are triangular in their cross section along the circumferential direction of the tire. A width W and a height h in the tread surface of the projected parts 2, the tread width as TW and the width in the tread surface of the main groove 1 as OTW, are 2 mm≤w≤TW×1%, 2 mm≤h≤OTW×5%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire excellent in wear resistance and low heat build-up, particularly a construction vehicle tire.

Conventionally, in construction vehicle tires, it has been required to improve low heat generation. For this reason, reducing the tread volume or adopting a low exothermic rubber is performed (for example, refer to Patent Document 1). In addition, increasing the number of grooves or increasing the number of pitches has been studied in order to increase the heat radiation area.
JP 2001-214000 A

  However, the above-described method for improving low heat generation has a problem that wearability may be deteriorated.

  Then, in view of said problem, an object of this invention is to provide the pneumatic tire which improves low heat buildup, without impairing abrasion resistance.

  In order to solve the above problems, a feature of the present invention is a pneumatic tire having a main groove formed in a tread along the tire circumferential direction, wherein at least one side surface of the main groove has a mold removal direction. A plurality of ridge-shaped protrusions extending along the edge, and the protrusions are substantially tapered toward the tip, and the width W and the height h of the protrusions on the tread surface are TW of the tread width The gist of the present invention is a pneumatic tire where 2 mm ≦ w ≦ TW × 1% and 2 mm ≦ h ≦ OTW × 5%, where OTW is the width of the tread surface of the main groove.

  According to the pneumatic tire according to the features of the present invention, the increase in the volume of the tread rubber can be minimized, the heat radiation area can be greatly increased, and the low heat build-up can be improved without impairing the wear resistance. Can do.

  Conventional treads for construction vehicle tires have high hardness and a thick tread gauge, so it is difficult to remove the mold. However, the present invention provides such a problem because the protrusion is provided along the mold removal direction. Hateful.

  Moreover, since the protrusion is substantially tapered toward the tip, the increase in volume can be minimized and the surface area can be effectively increased. Here, the “substantially tapered shape” refers to a shape whose width decreases from the bottom to the tip of the protrusion.

  Further, the width W and the height h on the tread surface of the projection are 2 mm ≦ w ≦ TW × 1%, 2 mm ≦ h ≦ OTW × 5%, where TW is the tread width and OTW is the width of the tread surface of the main groove. is there. If the width W is smaller than 2 mm, it is clogged with mud, soil, etc., and it is difficult to dissipate heat. If it is larger than TW × 1%, the volume increases and heat generation increases. If the height h is smaller than 2 mm, it is clogged with mud, soil, etc., and it is difficult to dissipate heat. If it is larger than OTW × 5%, the volume increases and heat generation increases.

  Further, the depth d of the protrusion provided on the pneumatic tire according to the feature of the present invention is preferably d ≧ OTD × 80%, where the depth of the main groove is OTD. This is to suppress cracks near the groove bottom due to surface strain during rolling.

  Moreover, it is preferable that the inclination | tilt angle (alpha) with respect to the mold extraction direction of the protrusion part provided in the pneumatic tire which concerns on the characteristic of this invention is 3 degrees <= alpha <= 15 degrees. When the inclination angle α is smaller than 3 °, moldability is deteriorated, resulting in manufacturing defects such as rubber chipping and mold adhesion. When the inclination angle α is larger than 15 °, the groove width is increased and wear resistance is deteriorated.

  In addition, the pneumatic tire according to the feature of the present invention is preferably used for a tire for a construction vehicle because the low heat build-up can be improved without impairing the wear resistance.

  ADVANTAGE OF THE INVENTION According to this invention, the pneumatic tire which improves low heat generating property can be provided, without impairing abrasion resistance.

  Next, embodiments of the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones. Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Composition of pneumatic tire)
As shown in FIG. 1A, the pneumatic tire according to the embodiment of the present invention has a main groove 1 having a depth of 70 mm or more formed in the tread 3 along the tire circumferential direction. At least one side surface of the main groove 1 is provided with a plurality of bank-shaped protrusions 2 extending along the mold drawing direction (arrow A direction).

  As shown in FIG. 1B, the protrusion 2 has a triangular shape in a cross section along the tire circumferential direction. Further, the width W and height h on the tread surface of the protrusion 2 are 2 mm ≦ w ≦ TW × 1%, 2 mm ≦ h ≦ OTW × 5, where TW is the tread width and OTW is the width of the tread surface of the main groove 1. %.

  Further, as shown in FIG. 1A, the depth d of the protrusion 2 is d ≧ OTD × 80%, where the depth of the main groove 1 is OTD.

  Further, as shown in FIG. 1C, the inclination angle α of the protrusion 2 with respect to the mold drawing direction (dotted line portion) is 3 ° ≦ α ≦ 15 ° in the cross section including the tire rotation axis.

(Modification)
The protrusion 2 provided on the pneumatic tire according to the embodiment of the present invention is not limited to the shape shown in FIG. 1, and may have the shape shown in FIGS. 2 to 4, for example.

  FIG. 2 shows the protrusion 2 having a trapezoidal shape in a cross section along the tire circumferential direction. As shown in FIG. 2B, the width W and height h of the protrusion 2 on the tread surface are 2 mm ≦ w ≦ TW × 1%, where TW is the tread width and OTW is the width of the tread surface of the main groove 1. 2 mm ≦ h ≦ OTW × 5%. Further, as shown in FIG. 2A, the depth d of the protrusion 2 is d ≧ OTD × 80%, where the depth of the main groove 1 is OTD. Similarly to FIG. 1C, the inclination angle α of the protrusion 2 with respect to the mold drawing direction (dotted line direction) is 3 ° ≦ α ≦ 15 ° in the cross section including the tire rotation axis.

  FIG. 3 shows the protrusion 2 whose tip is corrugated in a cross section along the tire circumferential direction. As shown in FIG. 3B, the width W and height h of the protrusion 2 on the tread surface are 2 mm ≦ w ≦ TW × 1%, where TW is the tread width and OTW is the width of the tread surface of the main groove 1. 2 mm ≦ h ≦ OTW × 5%. Further, as shown in FIG. 3A, the depth d of the protrusion 2 is d ≧ OTD × 80%, where the depth of the main groove 1 is OTD. Similarly to FIG. 1C, the inclination angle α of the protrusion 2 with respect to the mold drawing direction (dotted line direction) is 3 ° ≦ α ≦ 15 ° in the cross section including the tire rotation axis.

  Since the pneumatic tire shown in FIGS. 1 to 3 is manufactured by split mold, the mold drawing direction (arrow A direction) is the outer side in the tire radial direction, but the mold drawing direction is not limited to this.

  Next, an example of a pneumatic tire manufactured by a full mold is shown in FIG.

  As shown to Fig.4 (a), the mold extraction direction (arrow B direction) of the pneumatic tire manufactured by a full mold is a tire circumferential direction. Also in this case, a plurality of triangular protrusions 2 are provided along the mold drawing direction (arrow B direction). As shown in FIG. 4B, the width W and height h on the tread surface of the protrusion 2 are 2 mm ≦ w ≦ TW × 1%, where TW is the tread width and OTW is the width of the tread surface of the main groove 1. 2 mm ≦ h ≦ OTW × 5%. Further, as shown in FIG. 4A, the depth d of the protrusion 2 is d ≧ OTD × 80%, where the depth of the main groove 1 is OTD. Further, the inclination angle α of the protrusion 2 with respect to the mold drawing direction (arrow B direction) is 3 ° ≦ α ≦ 15 ° in the tread plan view as shown in FIG. 4C.

(Function and effect)
In the pneumatic tire according to the present embodiment, a plurality of bank-shaped protrusions 2 extending along the mold drawing direction are provided on at least one side surface of the main groove 1, and the protrusions 2 are directed toward the tip. A substantially tapered shape. For this reason, according to the pneumatic tire according to the present embodiment, the increase in the volume of the tread rubber can be minimized, the heat radiation area can be greatly increased, and the low heat generation property is improved without impairing the wear resistance. Can be made. Moreover, since the protrusion part 2 is a taper shape toward the said front-end | tip, it can suppress a volume increase to the minimum and can increase a surface area effectively.

  Further, the width W and the height h on the tread surface of the protrusion 2 are 2 mm ≦ w ≦ TW × 1%, 2 mm ≦ h ≦ OTW × 5%, where the tread width is TW and the width of the main groove tread surface is OTW. It is. If the width W is smaller than 2 mm, it is clogged with mud, soil, etc., and it is difficult to dissipate heat. If it is larger than TW × 1%, the volume increases and heat generation increases. If the height h is smaller than 2 mm, it is clogged with mud, soil, etc., and it is difficult to dissipate heat. If it is larger than OTW × 5%, the volume increases and heat generation increases.

  The depth d of the protrusion 2 is d ≧ OTD × 80%, where the depth of the main groove is OTD. For this reason, cracks near the groove bottom due to surface strain during rolling can be suppressed.

  Further, the inclination angle α of the protrusion 2 with respect to the mold drawing direction is 3 ° ≦ α ≦ 15 °. When the inclination angle α is smaller than 3 °, moldability is deteriorated, resulting in manufacturing defects such as rubber chipping and mold adhesion. When the inclination angle α is larger than 15 °, the groove width is increased and wear resistance is deteriorated.

  As described above, the pneumatic tire according to the present embodiment can improve the low heat generation without impairing the wear resistance, and thus is preferably used for a tire for a construction vehicle.

  The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to the following examples.

  In order to confirm the effect of the present invention, one type of tire of an example to which the present invention was applied and one type of conventional tire were manufactured, and the wear resistance and low heat build-up were examined. Both the example and the conventional example were tires of size 40.00R57. In the following tests, normal internal pressure and normal rim defined by TRA (The Tire and Rim Association Inc.) were used.

  Further, Example 1 used a tire having the protruding portion 2 having the shape shown in FIG. 1, and Conventional Example 1 used a tire having no protruding portion 2.

(Low heat generation)
Each tire is assembled on a TRA regular rim, and after running for 24 hours with regular load and regular internal pressure, a thermocouple is inserted through a narrow hole provided in the center of the block in advance, and a temperature of 5 mm above the outermost layer is The average value was calculated. The test results were based on Conventional Example 1 (0 ° C.) and the temperature difference was displayed. The larger the negative value, the lower the heat generation.

(Abrasion resistance)
Each tire is assembled on a TRA regular rim, attached to the front wheel of a 190 ton dump truck with a normal load and a normal internal pressure, and after traveling for 1000 hours at a speed of about 10 km / h at a substantially constant speed, the tread is divided into 8 parts in the width direction. By measuring the remaining groove, the average value of the gauge required for running was calculated as the amount of wear. The test results were indexed with the value obtained by dividing the amount of wear divided by the running time, with the value of Conventional Example 1 being 100. It shows that it is excellent in abrasion resistance, so that a value is large.

The conditions and results are shown in Table 1.

(result)
In Example 1, compared with Conventional Example 1, the low heat build-up was improved without impairing the wear resistance. Therefore, it can be seen that the provision of the substantially tapered protrusion 2 extending along the mold removal direction on at least one side surface of the main groove 1 improves the low heat generation without impairing the wear resistance. It was.

  In addition, the width W and the height h on the tread surface of the protrusion 2 according to Example 1 are 2 mm ≦ w ≦ TW × 1%, 2 mm ≦ h, where the tread width is TW and the width of the main groove tread surface is OTW. ≦ OTW × 5%. The depth d of the protrusion 2 was d ≧ OTD × 80%, where the depth of the main groove was OTD. Further, the inclination angle α of the protrusion 2 with respect to the mold drawing direction was 3 ° ≦ α ≦ 15 °.

(A) is a perspective view of the pneumatic tire which concerns on this embodiment, (b) is sectional drawing along the tire circumferential direction of the projection part of the pneumatic tire which concerns on this embodiment, (c) These are sectional views containing the tire rotation axis of the pneumatic tire concerning this embodiment. (A) is a perspective view of the pneumatic tire which concerns on a modification, (b) is sectional drawing along the tire peripheral direction of the projection part of the pneumatic tire which concerns on a modification. (A) is a perspective view of the pneumatic tire which concerns on a modification, (b) is sectional drawing along the tire peripheral direction of the projection part of the pneumatic tire which concerns on a modification. (A) is a perspective view of a pneumatic tire according to a modified example, (b) is a cross-sectional view along the tire circumferential direction of the protrusion of the pneumatic tire according to the modified example, (c), It is a tread top view of a pneumatic tire concerning a modification.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Main groove 2 ... Protruding part 3 ... Tread A, B ... Mold extraction direction

Claims (4)

A pneumatic tire having a main groove formed along a tire circumferential direction on a tread,
At least one side surface of the main groove is provided with a plurality of bank-shaped protrusions extending along the mold drawing direction,
The projection is substantially tapered toward the tip,
The width W and height h on the tread surface of the protrusion are TW as the tread width and OTW as the width of the main groove tread surface,
2 mm ≦ w ≦ TW × 1%,
2mm ≦ h ≦ OTW × 5%
A pneumatic tire characterized by being. The depth d of the protrusion is defined by OTD as the depth of the main groove.
d ≧ OTD × 80%
The pneumatic tire according to claim 1, wherein The inclination angle α of the protrusion with respect to the mold removal direction is:
3 ° ≦ α ≦ 15 °
The pneumatic tire according to claim 1, wherein the pneumatic tire is a tire.   It is a tire for construction vehicles, The pneumatic tire of any one of Claims 1-3 characterized by the above-mentioned.

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