JP5170416B2 - Pneumatic tires for snowy and snowy roads - Google Patents

Description

  The present invention relates to a pneumatic tire for icy and snowy roads used for passenger cars, trucks, buses and the like.

Conventionally, in pneumatic tires that have icy and snowy road performance, such as studless tires, the softness of the block can be increased by using a flexible rubber for the tread to increase adhesion to the road surface or by providing sipes on the tread block. The frictional force with respect to the road surface is improved by improving the property (see, for example, Patent Document 1).
Japanese Patent No. 3702958

  However, since the tread surface of a tire manufactured by vulcanization molding in a mold is smooth, the surface of the rubber must be moderately worn by actual running in order to obtain the performance required for running on icy and snowy roads. Therefore, there is a problem in that sufficient running performance on icy and snowy roads cannot be exhibited in the early stage of wear (initial use when new).

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to provide air for snowy and snowy roads that can sufficiently obtain the performance required for running on snowy and snowy roads even in the initial use when new. To provide tires.

In order to achieve the above object, the present invention provides a tread portion with a plurality of vertical grooves extending in the tire circumferential direction, a plurality of horizontal grooves extending in the tire width direction, and a plurality of blocks defined by the vertical grooves and the horizontal grooves. In the provided pneumatic tire for snowy and snowy road, the depth in the tire radial direction gradually increases from the contact surface of the block to the upper part of the wall surface of the longitudinal groove toward the longitudinal groove side at the tire width direction end of the block. Notch portions are provided at a plurality of locations in the tire circumferential direction, and each notch portion has a width in the tire circumferential direction of 1 mm or more and 3 mm or less, a depth in the tire width direction on the ground contact surface of the block of 1 mm or more and 5 mm or less, and a wall surface of the longitudinal groove. formed as the depth of the tire radial direction is 1mm or 3mm or less, more width and depth narrow grooves extending in the tire width direction to the ground surface of the block is 0.1mm or more, respectively 1.0 It provided to be less than m, to form a respective narrow grooves so as to communicate with the notch portion in the tire width direction end portions.

As a result, a plurality of notches are provided at the tire width direction end of the block, so that a force for scraping snow is applied by the notch and the block edge length is provided by the amount of the notch provided. Will increase. In this case, the notch is formed so that the depth in the tire radial direction gradually increases from the contact surface of the block to the upper part of the wall surface of the longitudinal groove toward the longitudinal groove side. The reduction in rigidity is suppressed. In addition, not only the notch but also each narrow groove ensures the snow and snow road running performance at the initial stage of block wear, and each narrow groove is shallow, so it wears out early, and the original properties of the block rubber are demonstrated early. Is done. In this case, since each narrow groove is formed so that the end in the tire width direction communicates with the notch, the end of each narrow groove is formed separately from the notch at the end in the tire width direction of the block. There is nothing to do.

According to the present invention, since a force for scraping snow is applied by the notch portion of the block, the braking force can be improved. Further, since the edge length of the block is increased by the amount of the cutout portion, the edge effect on ice can be improved. Therefore, the performance required for running on icy and snowy roads can be sufficiently obtained even in the initial use when a new article is used. In this case, since it is possible to suppress a decrease in the rigidity of the block due to the notch, it is possible to improve steering stability. In addition, not only the notch but also each narrow groove can ensure the snow and snow road running performance in the early stage of wear of the block, and each narrow groove is shallow, so it wears out early, and the original characteristics of the block's rubber can be improved early. Can be demonstrated. In this case, since the end of each narrow groove is not formed separately from the notch at the end of the block in the tire width direction, the rigidity of the end of the block in the tire width direction is reduced even if each narrow groove is provided. There is an advantage of not letting it. Moreover, since it can drain to a notch part from a narrow groove, the improvement of a water film removal effect can also be aimed at.

1 to 5 show a first premise technique of the present invention. FIG. 1 is a partial plan view of a pneumatic tire for an icy and snowy road, FIG. 2 is an enlarged perspective view of a main part of a tread, and FIG. 4 is an enlarged plan view, FIG. 4 is an enlarged front view of the main part, and FIG. 5 is a side view of the block.

  In this pneumatic tire for snowy and snowy roads, a plurality of vertical grooves 2 extending in the tire circumferential direction, a plurality of horizontal grooves 3 extending in the tire width direction, a vertical groove 2 and a horizontal groove are formed in a tread portion 1 formed on the outer peripheral surface side of the tire. A block 4 defined by 3 is provided, and a plurality of notches 5 are provided at intervals in the tire circumferential direction at the tire width direction end of the block 4. A plurality of sipes (not shown) extending in the tire width direction are provided on the ground contact surface of the block 4.

  Each notch portion 5 is formed such that the depth H in the tire radial direction gradually increases from the ground contact surface of the block 4 to the upper portion of the wall surface of the longitudinal groove 2 toward the longitudinal groove 2 side. A straight downward slope is formed from the ground contact surface side of the block 7 toward the wall surface side of the vertical groove 2. In this case, each notch portion 5 has a width W in the tire circumferential direction of 1 mm to 3 mm, a depth D in the tire width direction on the ground contact surface of the block of 1 mm to 5 mm, and a depth in the tire radial direction on the wall surface of the longitudinal groove. H is formed to be 1 mm or more and 3 mm or less. Further, each notch 5 is a tire of the notch 5 provided in the block 4 on the end side in the tire width direction with respect to the interval P1 in the tire circumferential direction of the notch 5 provided in the block 4 on the center side in the tire width direction. They are arranged so as to be wider than the circumferential interval P2.

According to the pneumatic tire , since the plurality of cutout portions 5 are provided at the tire width direction end portion of the block 4, a force for scraping snow by the cutout portions 5 is applied on the snow, thereby improving the braking force. Can do. Further, since the edge length of the block 4 is increased by the amount of the cutout portion 5, the edge effect on ice can be improved. Therefore, the performance required for running on icy and snowy roads can be sufficiently obtained even in the initial use when a new article is used. In this case, the notch portion 5 is formed so that the depth H in the tire radial direction gradually increases from the contact surface of the block 4 to the upper wall surface of the longitudinal groove 2 toward the longitudinal groove 2 side. The rigidity reduction of the block 4 by the part 5 can be suppressed, and the steering stability can be improved.

  Further, each notch portion 5 has a tire circumferential width W of 1 mm or more and 3 mm or less, a tire width direction depth D of the block contact surface of 1 mm or more and 5 mm or less, and a tire radial depth on the wall surface of the longitudinal groove 2. Since H is formed so as to be 1 mm or more and 3 mm or less, the cutout portion 5 is not too small to improve the performance on ice and snowy roads. Moreover, since the notch 5 is not too large, the rigidity of the block 4 can be sufficiently ensured.

  Further, each notch portion 5 is a tire of the notch portion 5 provided in the block 4 on the tire width direction end side with a distance P1 in the tire circumferential direction of the notch portion 5 provided in the block 4 on the tire width direction center side. Since it is arranged so as to be wider than the circumferential interval P2, the rigidity of the tread portion 1 on the center side in the tire width direction can be made higher than that on the end portion side in the tire width direction, improving on-ice braking performance and dry braking performance. Can be achieved.

FIG. 6 is a side view of the block showing the second premise technique of the present invention, in which the notch portion 5 of the block 4 is inclined from the bottom portion 5a in the tire radial direction toward the lateral groove 3 side close to the tire circumferential direction. Formed. As a result, the distance L from the lateral groove 3 close to the tire circumferential direction to the bottom 5a of the notch 5 is increased, and the collapse to the side of the lateral groove 3 is reduced accordingly, so that the rigidity of the block 4 in the tire circumferential direction is increased. be able to. In this case, by forming the inclination angle θ of the notch 5 so as to be 10 ° or more and 40 ° or less, the inclination angle θ is not too small, and the effect of suppressing the reduction in rigidity is not insufficient. In addition, since the tilt angle θ is too large and no dripping wear occurs, it is possible to prevent the wear form from deteriorating.

7 to 9 show an embodiment of the present invention. FIG. 7 is an enlarged perspective view of a main part of the tread, FIG. 8 is an enlarged plan view of the main part, and FIG. 9 is an enlarged front view of the main part. In this embodiment, a plurality of narrow grooves 6 extending obliquely in the tire width direction are provided on the ground contact surface of the block 4 so that the width and depth are 0.1 mm or more and 1.0 mm or less, respectively. As a result, not only the notch 5 but also each narrow groove 6 can ensure the snow and snow road running performance at the initial stage of wear of the block 4 and each narrow groove 6 is shallow and wears out early. The original characteristics of rubber can be exhibited at an early stage. In this case, since each narrow groove 6 is formed such that the end in the tire width direction communicates with the notch 5, the end of each narrow groove 6 is separated from the notch 5 at the end in the tire width direction of the block 4. There is an advantage that the rigidity of the end portion in the tire width direction of the block 4 is not lowered even if the narrow grooves 6 are provided. Moreover, since it can drain to the notch part 5 from the fine groove 6, the improvement of a water film removal effect can also be aimed at.

As shown in FIG. 10, for Examples 1 to 4 and Comparative Examples of the pneumatic tires , tests for steering stability, performance on snow and performance on ice were performed, and the following results were obtained. A new tire having a tire size of 215 / 60R16 was used and the tire pressure was 230 kPa. In the comparative example and the example 1, the notch portion having no inclination with respect to the tire circumferential direction was used, and the maximum depth H of the notch portion was 5 mm in the comparative example and 3 mm in the example 1. Further, in Examples 2 to 4, the one in which the notch is inclined with respect to the tire circumferential direction as in the second embodiment is used, and the maximum depth H of the notch is 3 mm in Example 2. Example 3 was 2 mm, and Example 4 was 1 mm.

In tests on snow and on ice, the vehicle travels on snow and ice at a speed of 60 km / h, and the reciprocal of the distance from the start of braking to the stop of the vehicle is indexed. The evaluation was indexed. The evaluation method was evaluated by an index when the comparative example was set to 100, and a higher numerical value was determined as superior. The results of the tests, real施例1-4 steering stability, the snow performance and on-ice performance, results that are better than the respective Comparative Examples were obtained.

  Next, in addition to Example 1 in which the width W of the notch in the tire circumferential direction was 2 mm, Example 5 with a width W of 1 mm and Example 6 with a width W of 3 mm were subjected to the same test as the above test. The result shown in FIG. 11 was obtained. Here, evaluation was performed using an index when Example 5 having a width W of 1 mm was set to 100, and a higher numerical value was determined as superior. As a result of the test, it was found that Example 1 having a width W of 2 mm was the best among Examples 1, 5 and 6.

The fragmentary top view of the pneumatic tire for snowy and snowy roads showing the first prerequisite technology of the present invention Enlarged perspective view of the main part of the tread An enlarged plan view of the main part of the tread Enlarged front view of the main part of the tread Side view of block Side view of the block showing the second prerequisite technology of the present invention The principal part expansion perspective view of the tread which shows one Embodiment of this invention. An enlarged plan view of the main part of the tread Enlarged front view of the main part of the tread Diagram showing test results Diagram showing test results

  DESCRIPTION OF SYMBOLS 1 ... Tread part, 2 ... Vertical groove, 3 ... Horizontal groove, 4 ... Block, 5 ... Notch part, 5a ... Bottom part, 6 ... Narrow groove.

Claims (3)

In the pneumatic tire for ice and snowy roads provided with a plurality of vertical grooves extending in the tire circumferential direction, a plurality of horizontal grooves extending in the tire width direction, and a plurality of blocks defined by the vertical grooves and the horizontal grooves in the tread portion,
Notches where the depth in the tire radial direction gradually increases from the ground contact surface of the block to the upper portion of the wall surface of the longitudinal groove toward the longitudinal groove side are formed at a plurality of locations in the tire circumferential direction at the tire width direction end of the block. Provided,
Each notch has a width in the tire circumferential direction of 1 mm to 3 mm, a depth in the tire width direction on the ground contact surface of the block of 1 mm to 5 mm, and a depth in the tire radial direction of the wall surface of the longitudinal groove of 1 mm to 3 mm. so as to form,
A plurality of narrow grooves extending in the tire width direction are provided on the ground contact surface of the block so that the width and depth are 0.1 mm or more and 1.0 mm or less, respectively.
A pneumatic tire for icy and snowy roads, characterized in that each narrow groove is formed so that the end in the tire width direction communicates with the notch . Each notch is formed so as to be inclined from the bottom in the tire radial direction toward the lateral groove near the tire circumferential direction, and the inclination angle is 10 ° or more and 40 ° or less. The pneumatic tire for icy and snowy roads according to claim 1. The said each notch part has been arrange | positioned so that the space | interval of the tire circumferential direction of the tire width direction center side may become wider than the space | interval of the tire circumferential direction of the tire width direction edge part side. Pneumatic tires for icy and snowy roads.

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