FI56948C - PNEUMATIC DAECK - Google Patents

Description

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C (45) Patent granted on 12 05 1930 Patent oeddelat '(51) Kv.ik. * / Int.as B 60 C 11/04 · FINLAND - FINLAND (21) p «« n «lh» l' »mu * - P »tGnttn» fivecnlnf l * + 28/7 * + (22) H «k * ml» pllvl - An »öknlnf« d »| 10.05-7 * + '* (13) Alkupllvt — Glltl | h «t * da | 10.05.7 * + (41) Interpreters lulklMk ·! - Bllvlt ofluntllj 13.11.7 * +

Patents and registries .... ...... ..........

«,. . . . (44) Date of issue of the letter. - Q

Patent »och registerstyrelsen '' amOcm uti» | d och utUkriftun publkund 31.01.80, (32) (33) (31) Pyydetty «tuolkwi — Bagird prlorltet 12.05.73

England-England (GB) 22728/73 (71) Dunlop Limited, Dunlop House, Ryder Street, St. James's, London S.W.l,

This invention relates to pneumatic tires. The present invention relates to pneumatic tires. Anthony Mark Mills, Sutton Coldfield, Warwickshire, England-England (GB) (7 * +) Oy Jalo Ant-Wuorinen Ah (5 * +) Pneumatic tire and more particularly motorcycle tires, especially for driving on soft ground.

It is known to equip motorcycle tires for driving (and racing) on soft ground with a number of buttons, usually arranged transversely in rows. The pieces are usually rectangular in shape and their edges and associated sides are circumferential to the ring and transverse to this direction. Generally, the transverse edges and sides provide a forward grip on the motorcycle straight ahead and when driving in a substantially vertical position, and the circumferential edges and sides provide a grip in the transverse direction, for example when cornering.

The invention relates to a pneumatic tire suitable for a motorcycle of the basic type disclosed in DE-A-2 106 718, comprising a tread provided with transverse rows of studs, the studs intersecting or close to the central circumferential plane of the tire being provided with longer transverse edges than the studs at the ends of the rows.

The tire according to the invention is characterized in that the pieces at the ends of the rows are deeper than the formulas at or near the central circumferential plane of the ring, the depth of the piece being the distance measured perpendicular to the ground contact surface between this surface and the tire surface. The placement of the pieces themselves in rows on the tread of the tire in the tire according to the invention corresponds to the basic structure known from DE application publication 2 106 718. The rows preferably have the same number of pieces and the pieces of one row are moved towards the other side of the ring and the pieces of two adjacent rows are moved towards the opposite side of the ring.

The pieces at the ends of the rows are preferably smaller in area than the pieces intersecting or close to the circumferential plane of the tire tread. Therefore, with a certain force, the pressure acting on these end pieces is relatively higher and allows these pieces to penetrate deeper into the soft ground and to provide increased gripping power, especially in the transverse direction of the tire, for example when cornering. This smaller surface area is due to the fact that the pieces at the ends of the rows have shorter transverse edges than the pieces at or near the central circumferential plane of the ring, and their circumferential edges can also be shortened to further reduce the area of the pieces at the ends of the rows. However, this would reduce the tensile power or grip of the circumferential edge and the associated side, and therefore some optimization is needed. In order to maintain the lateral gripping effect of the rim, it has been found that the circumferential length of the piece at the end of the row should preferably not be less than the circumferential length of the piece intersecting or close to the circumferential plane of the ring. Alternatively, the ratio of the circumferential length of the piece to the radial distance between the base of the piece and the axis of the ring is greater in the piece at the end of the row, i. on the shoulder of the tire than on a button intersecting or close to the center of the circumference of the tire.

The word "transverse" as used in this specification means perpendicular to the circumferential plane of the tire.

An embodiment of the invention, a motorcycle tire with a size of 5.00 x 18, will be described by way of example with reference to the accompanying drawing, in which

Fig. 1 shows an axial cross-section through the ring along the line I-I in Fig. 2, with the tire carcass comprising four diagonal layers being omitted; 56948

Fig. 2 is a plan view of the tread of the tire with the button flaps in the position they would be if the tire surface without the pins were flat;

Fig. 3 is a sectional view of a portion of the tread of the tire taken along line II-II of Fig. 2;

Figure 4 is a sectional view of a portion of the tread of the tire taken along line III-III of Figure 2.

The different dimensions of the parts in the drawing are shown in the following table: 11 21.5 mm to 12 7.5 mm 13 17.0 mm 14 17.0 mm 15 19.5 mm 16 19.0 mm 17 4.0 mm 18 21 .0 mm 19 21.0 mm 20 21.0 mm 21 11.5 mm 22 5.0 mm 23 8.0 mm 24 7.0 mm 25 3.0 mm 26 15.5 mm 27 19.5 mm 28 8 .0 mm

It should be noted that although the relative dimensions of the pieces shown in Figure 2 are correct, the distances between the pieces will be distorted due to the curvature of the tire surface. In particular, the circumferential distances between the pieces next to the shoulder of the tire will decrease due to the fact that the circumferential length of the tread shoulder of the tire is smaller compared to the middle part of the tread, i. the central circumferential plane.

The ring 1 comprises a tread provided with a plurality of knobs A, B, C, D and E, the knobs of which are rectangular in shape from their ground contacting surface 2, the two edges of the surface running in the circumferential direction and the other two in the transverse direction, i. at right angles to the circumferential edges. The tire also comprises 4 56948 a rubber base layer 3 of the pieces, the thickness of which is A- mm at the circumferential plane of the tire, which thickness gradually decreases towards the lower sidewall areas of the tire.

The pieces are arranged in rows running across the tread, each row having five pieces A, B, C, D and E, arranged in an interleaved manner, the rows of pieces being moved alternately towards both sides of the tire so that each piece is in the openings of two adjacent rows. except for the outermost piece at the ends of the rows.

Each row of buttons is identical in terms of dimensions and relative position, with the exception that the alternating rows are opposite. Thus, the pieces A, E, A, E are closest to one side of the ring and the pieces E, A, E, A on the other side. Button A is closer to its diaphragm area than button E.

All buttons are rectangular in shape and have two circumferential edges and two transverse edges. The lengths of the transverse edges decrease the longer the axial inner edge of the button in the row is from the central circumferential plane of the tire. The transverse length of the center button of each row is greater than that of any button in the same row, and this piece intersects the ring circumferential plane X-X asymmetrically. The circumferential edge length of the pieces in a row is the same. The depth of the pieces measured from the ground contacting surface of the piece to the surface of the tire between the rows of buttons increases the farther the piece is from the center circumferential plane of the tire. The middle button is therefore lower than any other button in a row. For example, the depth 26 of the piece C is 15.5 mm, while the depth 27 of the piece A at the other end of the row is 19.5 mm.

To improve grip in the transverse direction of the ring, there are second and fourth knobs (knobs B and D) in each row provided with a low circumferential groove with a semicircular cross-section 5 · These semicircular grooves provide additional t artunt areunoj a.

Given the large force that can affect the pieces at the ends of the rows when cornering, the piece has a strong tendency to distort. In order to reduce the possibility of distortion and to improve the rigidity of this piece, a cross support 6 is generally placed between the outer piece of each row and the adjacent piece in the same row, i. between pieces A and B and pieces D and E.

5,56948

Given that the radius of the ring is smaller at the ends of the rows, the distance between adjacent rows at the ends of the rows is smaller than the corresponding distance between adjacent rows between the center buttons. If the rows are not far apart, the mud or soft ground that has fallen between the rows may compress as it moves laterally along the transverse channel between two adjacent rows. For this reason, the distances between the rows are much larger than the circumferential width of the pieces. In the structure shown, the distance 10 between the middle pieces in a row is 35 mm, while the length 11 of the circumferential edge is 21.5 mm, i.e. about 2/3 of the distance. By making the distances between the rows of najp suitable, the ground is stuck.

When the tire according to the invention is used in a forward movement and when braking in this direction, the tire's ✓ · mid-circumferential cuts and adjacent cubes are in contact with the ground and transfer coaxial force between the motorcycle and the ground.Longer transverse edges of the cuffs provide better grip during this type .

As the motorcycle tilts more when cornering, the tire tends to slide or slip sideways and the pieces on or near the tire shoulder come into contact with the ground. Since the ratio of the length of the circumferential edge of these pieces to their radius is relatively larger than the corresponding ratio of the pieces intersecting or close to the circumferential plane of the tire, the necessary grip is provided to prevent slipping or slipping in cornering. Because the contact area is smaller when cornering than when driving forward or braking, the stress on the single shoulder button at the end of the line, together with the fact that the shoulder area is smaller than the tire ridge or center button area, significantly increases the pressure on the individual shoulder button. the pressure acting on the brush button. The edge pieces therefore tend to penetrate the soft ground and thus provide a better lateral grip. The effect of the double edges of the piece to prevent slipping or slipping when cornering is therefore improved. The greater depth of the shoulder button compared to the depth of the middle button increases the surface area of the sides of the button through which the reaction force can act and

Claims (4)

56948 6 thus the effective pressure of the paint in contact with the sides of the piece is reduced. Combining different sized pieces as described above gives advantageous properties to the tire in all kinds of movements and the interleaved arrangement of rows of the same number of pieces results in a longer length of the leading edge in the contact area than in a ring with rows of alternately large numbers of pieces, e.g. A pneumatic tire, particularly suitable for mounting on a motorcycle, comprising a tread with transverse rows of studs, wherein the studs (C) intersecting or close to the central circumferential plane of the tire are provided with longer transverse edges than the studs (A, E) at the ends of the rows, characterized in , that the pieces at the ends of the rows (A, E) are deeper than the pieces (C) intersecting or close to the central circumferential plane of the ring, the depth of the piece being the distance measured perpendicular to the ground contact surface between this surface and the ring between the rows of studs. A pneumatic tire according to claim 1, characterized in that the circumferential length of the piece at the end of the rows is not less than the circumferential length of the piece intersecting or close to the central circumferential plane of the tire. Pneumatic tire according to Claim 1, characterized in that the ratio of the circumferential length of the piece to the radial distance between the base of the piece and the ring axis is greater in the row at the end of the row than in the section at or near the center circumferential plane of the tire. Pneumatic tire according to one of the preceding claims, characterized in that the rows have the same number of pieces, the pieces of one row being moved towards the other side of the ring and the pieces of two adjacent rows being moved towards the opposite side of the ring.