JPH02267007A - Pneumatic winter tire for heavy load - Google Patents

Abstract

PURPOSE:To improve the on-ice performance and abrasion resistance by providing a number of cuts parallel at a predetermined interval to cross each other at a predetermined crossing angle in a block formed of circumferential grooves and lateral grooves in a tread in such a way as to make the groove width zero when an inner pressure is not filled. CONSTITUTION:Cuts 4A, 4B are formed in a block 3 formed of circumferential grooves 1, 1' and lateral grooves 2 in a tread T at an interval (w) of 0.5-20mm, a crossing angle theta of 45-90 deg., and a depth (d) of about 0.5-3.0mm. These cuts 4A, 4B are formed in lines without groove substantially when an inner pressure is not filled in a tire. In this constitution, the on-ice running performance and abrasion resistance can be improved.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to the improvement of heavy-duty pneumatic winter tires, and more particularly to the improvement of heavy-duty pneumatic winter tires with improved ice running performance and wear resistance. This relates to winter tires.

(Prior Art) As winter tires used in winter, it is necessary to maintain driving force, braking force, and lateral force in order to satisfy the driving performance on ice, so tires with metal spikes on the tread have traditionally been known. It is being

However, these spiked tires have become a social problem because they damage the road when driving on dry paved roads free of snow or ice and cause problems such as dust pollution.

On the other hand, in recent years, studless tires that do not have spikes have been developed as tires for running on snow and ice, and the mainstream of these studless tires are those that have improved running performance on snow and ice due to a unique block pattern formed on the tread. occupies .

In other words, the tread of conventional studless tires has
Usually, a plurality of blocks are formed in the circumferential direction of a tire, divided by a plurality of circumferential main grooves and a plurality of lateral grooves extending from both ends of the tread to intersect with the circumferential grooves,
Each block is suitably provided with a notch or sipe having a width of about 1 mm.

Therefore, in conventional studless tires, when a driving force or a braking force is applied to the tire, the numerous edges generated by the notches improve the running performance on snow and ice due to the edge effect caused by grasping the hard road surface. Its effectiveness has been recognized and it is rapidly becoming popular.

(Problem to be solved by the invention) However, since the notches provided in the blocks of conventional studless tires have a width as described above, although it is small, when shearing force is applied to the blocks from the road surface, Since the blocks are significantly tilted and the rigidity is reduced, not only the ground contact on dry and icy roads is reduced, but also there is a risk that uneven wear will occur significantly.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the conventional heavy-duty pneumatic winter tires.

Therefore, an object of the present invention is to provide a heavy-duty pneumatic winter tire with improved running performance on ice and wear resistance.

[Structure of the Invention] (Means for Solving the Problems) That is, the heavy-duty pneumatic winter tire according to the first aspect of the present invention has a tread located in the crown portion of the tire that is continuous in the circumferential direction at predetermined intervals. The tire includes a plurality of extending circumferential grooves, a plurality of lateral grooves intersecting the circumferential grooves and arranged at approximately equal intervals in the circumferential direction, and blocks divided by these groove groups, and applying internal pressure to the tire with respect to the blocks. When not filled, the tire is formed with a large number of relatively shallow linear cuts that have substantially no groove width and are substantially parallel to each other, and the cuts are made with 0.
They are characterized in that they are provided at intervals of 5 to 20 mm.

Furthermore, the heavy-duty pneumatic winter tire according to the second aspect of the present invention has a plurality of circumferential grooves extending continuously in the circumferential direction at predetermined intervals in the tread located in the crown portion of the tire, and intersecting the circumferential grooves. A relatively shallow straight line that includes a plurality of lateral grooves arranged at approximately equal intervals in the circumferential direction and blocks divided by these groove groups, and that when the blocks are not filled with internal pressure in the tire, there is no substantial groove width. The tire is provided with a large number of notches substantially parallel to each other, and the notches are oriented in a certain direction in a specific block, are oriented in a direction that intersects with the notches in the specific block in other blocks, and the incisions in both directions are made. The angle made is 45~
within a range of 90 degrees, and the interval between these notches is 0.
It is characterized by being in the range of 5 to 20 mn.

(Function) In the tire of the present invention, shallow cuts having a substantially groove width are provided in the tread blocks at predetermined intervals, so that when an external force is applied to the ground contact surface during running, the blocks fall down and the ground contact performance is reduced. This improves ground contact when driving on dry and icy roads.
Uneven wear can be improved, and running performance on ice is advantageously improved.

In addition, the cuts made in the block are not made into one straight line group,
As a group of two or more straight lines with different inclination angles, the inclination angles are set in the range of 45 to 90 degrees, and the intervals between these cuts are set in the range of 0.5 to 20 mm, so ice
- It is possible to improve the frictional force not only in a specific direction but also in the longitudinal and lateral directions in a well-balanced manner.

Therefore, the heavy-duty pneumatic winter tire of the present invention has particularly excellent running performance on ice and is resistant to eccentricity. .

The purity has been greatly improved to [11], and it is particularly useful as a winter tire for heavy loads such as small trucks and trucks/buses.

(Example) Examples of the heavy-duty pneumatic winter tire of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a developed view of a tread portion showing a first embodiment (first invention) of a heavy-duty pneumatic winter tire of the present invention, FIG. Figure 3 shows a second embodiment (second embodiment) of the heavy-duty pneumatic winter tire of the present invention.
FIG. 2 is a cross-sectional explanatory diagram of a block showing the invention.

Note that although parts other than the tread are not shown in the drawings, the parts other than those shown, such as the radial carcass and belt layer, have a well-known structure.

In the first embodiment (first invention) shown in FIG. 1, the tread T of the pneumatic winter tire for heavy loads of the present invention has at least two By arranging the circumferential grooves 1.1 of the book and the central circumferential groove 1' which substantially divides the axial distance between these circumferential grooves 1.1 into three equal parts and extends parallel to them, the axial It is divided into almost equal intervals in the direction.

Further, by providing a large number of lateral grooves 2 which intersect the circumferential grooves 1.1'1 from both ends of the tread and extend continuously in a substantially polygonal manner toward the center of the central area, the tread T is It is divided into Block 3.

Furthermore, all of the blocks 3 have a plurality of notches 4A extending at an angle of 45 degrees upward to the right with respect to the circumferential direction and a plurality of cuts 4B extending at an angle of 45 degrees upward to the left with respect to the circumferential direction. It is located across the .

Here, the tread T is usually formed from relatively hard rubber, but in some cases softer rubber or foamed rubber may be used for at least a portion thereof.

Although the circumferential groove 1.1 and the central circumferential main groove 1' may be straight lines parallel to the circumferential direction, it is preferable that they have a bent line shape (deformed flang shape) as shown in the figure. can be formed as the deepest and widest of the grooves.

The lateral grooves 2 are arranged so that the intervals in the circumferential direction are approximately equal, and these also preferably have a polygonal line shape (deformed flang shape) as shown.

The groove width of this lateral groove 2 is equal to or less than the circumferential main groove 1.1'1, and the depth of the lateral groove 2 is equal to or slightly shallower than the circumferential main groove 1.1'1. It is desirable that

The number of cuts 4A and 4B provided in each block 3 can be arbitrarily changed depending on the use of the tire.

As shown in FIG. 2, the cuts 4A and 4B are formed at a distance W from each other and have a depth d, and form lines with virtually no width when the tire is not filled with internal pressure. It is cut into a shape. Moreover, these cuts have substantially no width even when filled with internal pressure.

Such cuts 4A and 4B can be formed, for example, by cutting the block 3 with a cutting tool such as a knife.

In the present invention, the crossing angle θ extending in different directions is 45 to 90 degrees, and the interval W therebetween is 0.5 to 20 mm.

Note that the depths of the cuts 4A and 4B are desirably formed relatively shallowly, within a range of 7.5 mm or less, and further in the range of 0.5 to 3.0 mm.

Further, the cuts 4A and 4B may have a zigzag shape, a wavy shape, a lightning bolt shape, a dogleg shape, etc. other than the straight shape shown in the figure.

The cuts 4A and 4B formed in the block 3 are
It is not necessary that all of the grooves have substantially no groove width when not filled with internal pressure, and in addition to these grooves, a groove having a width of about 0.7 mm can be made to coexist.

Further, the depths d of the cuts 4A and 4B do not need to be all constant; for example, shallow cuts and deep cuts may exist alternately.

Furthermore, the cuts 4A and 4B do not necessarily need to substantially cross the block 3, and may be interrupted in the middle of the block 3, or may not be provided at the end of the block.

By forming the mutually intersecting cuts 4A and 4B in each block 3 as described above, running performance on ice and wear resistance can be effectively improved.

Next, in the second embodiment (second invention) shown in FIG. 2, each block 3 has a cut 4 extending only in one direction, but the inclination angle of the cut between each block 3 is different. This is different from the first embodiment (first invention) described above.

That is, in the second embodiment, the notches 4A of the block 3A in the central area of the tread T are axially upward slightly to the left and are almost parallel to each other, and the notches 4B of the blocks 3B in both side areas of the tread T are approximately parallel to the axial direction. , are arranged almost parallel to the circumferential direction, and these cuts 4A and 4B
The angle formed by the cuts in both directions is in the range of 45 degrees or more, and the interval between these cuts 4A and 4B is 0.
It is characterized in that it is formed in a linear shape with substantially no groove width in the range of 5 to 20 mm and in a state where the tire is not filled with internal pressure.

Here, the specific block 3A whose notches 4A are all oriented in a certain direction, and the other block 3B whose notches 4B are oriented in a direction that intersects the notches 4A of the block 3A, are not necessarily arranged as shown in FIG. For example, if the angle between the cuts in both directions is in the range of 45 to 90 degrees and the interval between these cuts is in the range of 0.5 to 20 mrn, then blocks 3A and 3B can be formed in the radial or axial direction. It is also possible to alternately arrange the blocks 3A and 3B, or to randomly scatter the blocks 3A and 3B.

Next, the structure and effects of the heavy-duty pneumatic winter tire of the present invention will be explained in more detail using test examples.

(Test example) Tire size: LSR7,50R1614PR1 Rim used: 6.0OGS, Air pressure used: 6°50kg/cJ The tread part of an all-weather block pattern radial tire was tested as shown in Figures 1 and 2 above. A block pattern was formed and this tire was evaluated.

Note that other structures such as the radial carcass and belt layer of the tire and manufacturing conditions were similar to those of conventional tires, so details will be omitted.

That is, in FIGS. 1 and 2, the tread width: 1
40mm, zigzag circumferential main groove 1.1 groove width: 3-8
Separation, Depth: 15++ on, Groove width of center circumferential main groove 1':
5mm5 Depth: 15mrn, horizontal groove 2 groove width near discharge, depth: 12mm when forming a block pattern, the groove width, depth d, interval W and inclination angle of the cut were changed as follows, Tires A and B of the present invention were obtained.

On the other hand, for comparison, conventional tires A to E having no incisions and having incisions in only one direction were obtained.

Invention tire A Cutting width: 0 Cutting depth: 2. Omm Cut interval: 5.0++++n Inclination angle of right upward cut 4A = 45 degrees Inclination angle of left upward cut 4B = 45 degrees Present invention tire B Cut width 20 Cut depth: 2. Omm Cutting interval: 2. Omm Angle of inclination to the circumferential direction of the notch 4A of the block 3A in the central area of the tread: 50 degrees upward to the right Angle of inclination to the circumferential direction of the notch 4B of the block 3B in both side areas of the tread: 0
degree (parallel to the radial direction) Comparative tire A Depth of cut without cutting: 12. O+n+n Cut interval: 5. Om++ Inclination angle to circumferential direction: 45 degrees in all Comparison Tire C Cut width: 0 Cut depth: 12. O front cut interval + 5.0 mm Inclination angle to the circumferential direction: 45 degrees in all Inclination angles in the circumferential direction: 45 degrees in all Next, these seven types of tires were subjected to an actual vehicle feeling test under the following conditions to determine their driving performance on ice, The following table shows the results of evaluation of driving feeling and wear resistance.

Note that all of the following tables are shown by index evaluation when conventional tire B is set to 1.00, and the larger the index, the better the results.

Test vehicle for driving performance on ice: small truck, 3-ton vehicle Road surface: frozen road surface in Hokkaido in winter Evaluation method: Speed] The braking distance from braking to stopping at 0 km/h is expressed as an index using a reciprocal number.

Good ◎・・・Good○・・・ Fair △・・・Sometimes uneasy Table road surface: Kanto area, DRY, WET road surface (no snow) Speed: 20 to 100 km/h (high speed running) Evaluation method: Comparison of wear appearance (confirmed by main groove depth) (hereinafter referred to as essential margin)] 5 From the results shown in the table above, it is clear that the heavy-duty pneumatic winter tire of the present invention has a high level of balanced performance on ice and wear resistance.

On the other hand, the conventional tire A without notches has significantly poor running performance on ice.

In addition, the conventional tire B-
Tire E is also inferior to the favorite tires A and B in terms of running performance on ice and wear resistance.

[Effects of the Invention] As described above, the heavy-duty pneumatic winter tire of the present invention has the following advantages:
In particular, it has excellent running performance on ice and has a high wear resistance of 111%.
It has improved performance as a studless tire with a long lifespan.
It is particularly useful as a winter tire for heavy loads such as small trucks and trucks/buses.

[Brief explanation of drawings]

FIG. 1 is a developed view of a tread portion showing a first embodiment (first invention) of a heavy-duty pneumatic winter tire of the present invention, FIG. Figure 3 shows a second embodiment (second embodiment) of the heavy-duty pneumatic winter tire of the present invention.
FIG. 2 is a cross-sectional explanatory diagram of a block showing the invention. T...Tread...Circumferential groove 1'...Central circumferential groove 2...Transverse groove 3... ...Block 3A ... Central section blower 3B ... Both side section blower 4A ... Notch 4B ... Notch d ...・・Depth W・・・・・・・・・Interval Kuku

Claims (2)

[Claims] (1) a plurality of circumferential grooves that extend continuously in the circumferential direction at predetermined intervals in the tread located in the crown portion of the tire; and a plurality of lateral grooves that intersect with the circumferential grooves and are arranged at approximately equal intervals in the circumferential direction; a block divided by these groove groups, and when the tire is not filled with internal pressure in the block, the tire is provided with a large number of relatively shallow linear cuts that have substantially no groove width and are substantially parallel to each other, The depth of cut is 4
0.5 to 2 in the direction of intersection in the angle range of 5 to 90 degrees
A heavy-duty pneumatic winter tire characterized by the fact that each tire is provided at a spacing of 0 mm. (2) a plurality of circumferential grooves that extend continuously in the circumferential direction at predetermined intervals in the tread located in the crown portion of the tire; and a plurality of lateral grooves that intersect with the circumferential grooves and are arranged at approximately equal intervals in the circumferential direction; a block divided by these groove groups, and when the tire is not filled with internal pressure in the block, the tire is provided with a large number of relatively shallow linear cuts that have substantially no groove width and are substantially parallel to each other, The cut is
A specific block faces in a certain direction, another block faces in a direction that intersects with the cut in the specific block, the angle formed by the cuts in both directions is in the range of 45 to 90 degrees, and the interval between these cuts is 0.5~20m
A heavy-duty pneumatic winter tire characterized by being within the range of m.