JPH0425364Y2 - - Google Patents

Description

[Detailed explanation of the idea] This invention relates to a low noise pneumatic tire.

As pneumatic tires for automobiles, rib tires have vertical grooves that extend in the tire circumferential direction on the tread surface to increase skidding resistance and improve maneuverability. A large number of lateral grooves in the width direction (meridian direction) are provided so that one end opens to the outside at the tire shoulder end and the other end is located outside the center line (shoulder side) so that the left and right lateral grooves are not connected to each other to increase traction force. At the same time, a lug tire with good heat dissipation in the tire shoulder part, and a rib lug tire with both the above-mentioned vertical grooves and lateral grooves to have the characteristics of the above-mentioned rib tire and lug tire, that is, at least one tire near the center line in the circumferential direction of the tire. A tire is provided with a vertical groove, and a large number of horizontal grooves on the shoulder side of the vertical groove, one end of which opens outward at the tire shoulder end, and the other end located within the vertical groove or on the shoulder side of the vertical groove. known, and in these tires, by providing fin-like projections protruding in the groove width direction on the groove walls of the vertical groove or lateral groove,
A device is known that reduces the audible level by dispersing the frequency of the air column resonance tube formed by vertical or horizontal grooves, while relaxing the speed of airflow due to the pumping action when touching the ground (Utility Model No. 58). -Refer to Publication No. 22301).

However, the above-mentioned known pneumatic tires
The protruding length of the fin-like protrusion is large, and its tip extends longer than the groove center line of the vertical or horizontal groove, and the part that touches the vicinity of the groove bottom also protrudes beyond the groove center line in the same way as the upper part. Because it is long, when running on a wet road, the drainage of the vertical grooves etc. is hindered, reducing running stability, and when touching the ground, stress is applied to the connection between the fin-shaped protrusion and the groove bottom. The problem was that cracks were generated in the joints due to the concentration of cracks, which grew and shortened the life of the tire.

This invention provides at least one longitudinal groove continuous in the circumferential direction of the tire, and a large number of horizontal grooves on the shoulder side of this longitudinal groove, one end of which opens outward at the tire shoulder end, and the other end of which is inside the longitudinal groove. Or, in a pneumatic tire installed so as to be located on the shoulder side of the longitudinal groove, the noise level is maintained at the same level as the above-mentioned known pneumatic tires, and the running safety on wet roads is improved, and the fin-shaped protrusions This makes it difficult for cracks to occur at the connection between the tire and the groove bottom, extending the life of the tire.

That is, this invention provides at least one longitudinal groove continuous in the circumferential direction of the tire, and a plurality of lateral grooves on the shoulder side of the longitudinal groove, one end of which opens outward at the tire shoulder end, and the other end of which opens outward at the tire shoulder end. In a pneumatic tire that is located within the groove or on the shoulder side of the longitudinal groove, the lateral groove has a fin-like protrusion protruding from the groove wall in the groove width direction, and the fin-like protrusion protrudes from the groove wall in the groove width direction. The tip of the lower region is formed in a shape that is recessed toward the groove wall side than the tip of the upper region other than the lower region, and the protrusion length of the upper region is smaller than half the groove width, and the thickness is smaller than the protrusion length. This is a low-noise pneumatic tire that is characterized by

Examples of this invention will be described below with reference to the drawings.

In FIG. 1, 1 is the tread of the pneumatic tire, 2 is the shoulder, 3 is the vertical groove, 4 is the minor groove, and N is the circumferential center line, which extends between the minor groove 4 and the tire shoulder 2. A lateral groove 5 is provided that is substantially lateral to the tire circumferential center line N, and one end thereof opens to the outside of the tire shoulder end.
A pair of fin-like protrusions 6 are provided in a protruding manner facing each other. As shown in FIG.
b, and the tip of the bottom region 6b is connected from the tip of the upper region 6a to the groove wall 5a.
It is recessed to the side in a semicircular shape and is in contact with the groove bottom 5b.

Generally, when a tire rotates under load, each part of the tread 1 repeatedly contacts the ground every rotation, and large shear strains occur near the bottoms 5b of the vertical grooves 3 and lateral grooves 5 each time the tires touch the ground. When it leaves the ground, a large tensile strain occurs, and if there is a protrusion like a conventional fin-like protrusion in this part, stress will be concentrated at the base of this protrusion and cracks will easily occur. Since the fin-like protrusion 6 of the above embodiment is provided with the lower region 6b whose protrusion length is shorter than the upper region 6a, the concentration of stress is reduced, the occurrence of cracks is reduced, and the tire life is extended. It will be extended. And the lower region 6
Due to the presence of b, even when the tread 1 is in contact with the ground and the width of the lateral groove 5 is reduced and the upper region 6a of the fin-like protrusion 6 blocks most of the lateral groove 5, the vicinity of the groove bottom 5b is not blocked. It is open, making drainage easier when driving on wet roads and ensuring driving stability.

The protrusion length of the upper region 6a of the fin-like protrusion 6 is as follows:
It is set smaller than half the groove width of the lateral groove 5. That is, in FIG. 2, the protrusion length b of the upper region 6a at any position in the groove depth direction is smaller than half the groove width B at the above-mentioned arbitrary position, preferably 20 to 48% of the groove width B. is set to If the above-mentioned protrusion length b is less than 20% of the groove width B, nodes of vibration waves due to air column vibration are difficult to occur, and the effect of reducing noise cannot be obtained. Drainage resistance increases and driving safety decreases.

The cross-sectional shape of the fin-like projections 6 of the lateral grooves 5 may be any shape, such as a rectangular shape with a constant thickness as shown in FIG. 3, or a trapezoidal shape with an uneven thickness as shown in FIG. The average thickness t is smaller than the protrusion length b ₀ of the fin-like projections 6 on the surface of the tread 1, and is preferably set to 20 to 80% of the protrusion length b ₀ . If the above average thickness t is less than 20% of the protrusion length _b0 , the bending rigidity of the fin-like protrusions 6 will be low, and the resistance to the airflow pressure in the vertical grooves 3 will be insufficient, causing vibration waves due to air column vibration. On the other hand, if the protrusion length b is greater than ₀ , the bending rigidity described above becomes too high, the drainage resistance becomes excessive when running on a wet road, and running stability decreases, and the groove wall 3a Stress concentration occurs at the connection area and cracks are more likely to occur.

In the embodiments described above, one pair of fin-like projections 6 is sufficient for each horizontal groove 5, but the number is not limited to this. Further, one of the fin-like projections 6 can be slightly shifted from the opposing position of the other. Furthermore, similar fin-like protrusions 6 may be provided protrudingly on one or both sides of the groove wall of the vertical groove 3. However, in this case, the pitch of the fin-like protrusions 6 is preferably one in the ground contact length when the tire is pressed against the road surface under load. In addition, in this embodiment, the horizontal groove 5
One end opens outward at the shoulder 2, and the other end opens into a sub-groove 4 which is narrower and shallower than the vertical groove 3, but the other end of the horizontal groove 5 may be connected to the vertical groove 3. Of course, it is also possible to use one without the above-mentioned sub-groove 4.

As explained above, this invention provides a pneumatic tire with vertical grooves and horizontal grooves, in which fin-like protrusions are provided in the horizontal grooves that generate particularly large noises, and
The tip of the lower area of the weir plate is formed in a shape concave toward the groove wall, and its protrusion length and thickness are defined respectively, so it has both the characteristics of conventional rib tires and lug tires, and has both sideslip resistance and traction force. is large, the heat dissipation of the tire shoulder part is good, noise during running is kept low, drainage is good when running on wet roads, running stability is improved, and fin-shaped protrusions Cracks are less likely to occur at the connection with the groove bottom, extending the life of the tire.

[Brief explanation of the drawing]

Figure 1 is a plan view of the main parts of an embodiment of this invention, Figure 2 is a cross-sectional view of a horizontal groove, Figure 3 is a cross-sectional view of a weir plate, and Figure 4 is a cross-sectional view of a modified weir plate. be. 1... Tread, 2... Shoulder, 3... Vertical groove, 4... Minor groove, 5... Horizontal groove, 6... Fin-like projection, 6a... Upper region, 6b... Lower region, N...
...Circumferential center line of the tire.

Claims (1)

[Scope of utility model registration request] At least one longitudinal groove continuous in the circumferential direction of the tire is provided, and on the shoulder side of this longitudinal groove, a number of lateral grooves are provided, one end of which opens outward at the tire shoulder end, and the other end of which is inside or outside the longitudinal groove. In a pneumatic tire provided to be located on the shoulder side, a fin-like protrusion is provided in the above-mentioned lateral groove protruding from the groove wall in the groove width direction, and a lower region of the fin-like protrusion near the groove bottom is provided. The tip is formed in a shape that is recessed toward the groove wall side than the tip of the upper region excluding the lower region, and the protrusion length of the upper region is set to be smaller than half of the groove width, and the thickness is set to be smaller than the protrusion length. A low-noise pneumatic tire that is characterized by