JPS604403A - Bias tire - Google Patents

Abstract

PURPOSE:To enhance stiffness of a tread part, shorten the grounding length and ruduce a stationary steering force, by a method wherein conditions such as the material for a carcass and the strength of filaments are combined with each other, and the folding-back height of an end part of the carcass is set to be large. CONSTITUTION:The bias tire is provided with a rubber made tread 1, two belt layers 2A, 2B and a carcass 3A, 3B arranged in a bias pattern. In this case, the carcass 3A, 3B consists of, for example, a laminate of two carcass plies, wherein the filament strength, namely, denier number of ply cords costituting the carcass plies is 1,500 D/2, the number of the ply cords is 49-53 and the intersecting angle of the ply cords is about 31-35 deg.. The ends of the carcass plies 3A, 3B are folded back around bead wires 4a at a bead part 4, with the folding-back heights l1, l2 set to be not less than 60mm. and not less than 40mm., respectively. Accordingly, the tread part 1 is made to have a stiffness in the circumferential direction of 1,049-1,171kg.mm.<2>/mm. and a stiffness in the cross-sectional direction of 777- 795kg.mm.<2>/mm..

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to the structure of a bias tire.

[Prior art]

Bias tires for vehicles not only have lower carcass and trend part rigidity than radial tires, but also have a longer contact length relative to the contact width, and have a larger pneumatic trail in terms of cornering characteristics than conventional tires. I don't know (for example, Automotive Engineering Complete Book, Volume 12, Tires, published by Sankaido).

Brake (P10-11, P46-47).

On the other hand, the moment due to friction against the center of rotation during excavation is large, the steering force during excavation is large, and the pneumatic trail is large, so the slip angle that determines the cornering force necessary for turning is There is a problem that the self-lining torque is large and the steering force during turning is large.

[Purpose of the invention]

In view of the above points, the present invention improves the bending rigidity of the tread portion and the rigidity of the vertical wall portion, thereby reducing the ground contact length and pneumatic trail, thereby improving the steering force and the steering force during excavation. The purpose is to reduce the steering force when turning.

[Structure of the invention]

In order to achieve this objective, in the present invention, the bending rigidity of the tendon part is adjusted to 1049 to 1171 kg mA/II in the circumferential direction by combining the material of the carcass, the wire strength (denier number), the angle, and the number of implants.

777-795kg・mIL/111 in the cross-sectional direction! In addition, it is characterized in that the winding height of at least one bead portion of the carcass end is 60 degrees or more.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 and FIG. 2 are diagrams showing one embodiment of the present invention. In the figure, 1 is a rubber tread, 2A and 2B are two belt layers made of glass cord, steel cord, or nylon as a breaker, and 3A and 3B are multilayer ply cords running in the tire circumferential direction. The carcass 4 is a bead in a so-called bias arrangement, which is arranged diagonally at a predetermined angle and intersecting each other.

The above carcass 3A and 3B are made by laminating two carcass plies made of polyester. The unit that expresses thickness (the larger the number, the thicker it is) is 1500 D/2
, the number of ply cords used is 49 to 53, and the intersection angle of the ply cords is approximately 31 to 3 da in the circumferential direction at the crown portion 5. Here, the above denier number 15
00 D/2 means two twisted wires with a denier of 1500 D, and the number of strands is:
Warp threads in a woven ply cord
The unit width is 5011 m, the number of weft threads for
This value indicates how many codes are inside.

Then, as shown in FIG. 2, the carcass 3A is connected to the bead wire 4a at the bead portion 4.

The terminal of 3B is being rolled up, but its carcass is 3A.

The winding height of 3B is '1' + '1, and one side is 6 (1m
that's all.

I have them each set so that the other one is more than 40 points sharp. This improves the rigidity of the sidewall portion 6.

Here, the conditions for the carcass as described above are set to size 6.4.
As a result of the present inventor's test applied to a 0-14-4 PR tire, as shown in Table 1, the circumferential rigidity of the conventional tread portion 1 was 900 to 974 U·-/I11, and the cross-sectional rigidity was also was 9 mJ/- for 715 to 733, whereas in the case of the above example, the circumferential stiffness was 1049 to 117
1kg・-/dou, cross-sectional stiffness 777-795)g・
aJ/Sin and Sonzonn improved (For details on rigidity,
(Refer to Takeshi Hayashi, Composite Materials Engineering, Chapter 9, pages 538-543).

In addition, for Luka 2A and 2B, the denier number is 840 D.
/2 - Two nylon sheets pasted together were used.

Clothes 1 (Tire Buiz: 6JO-14-4P R) Next, looking at the experimental results on an actual vehicle, the air pressure was 2.0 kg/
i, when mounted on a 41A-JXI4 rim with a load of 435k19, the ground contact length of the conventional tire was 185 mm and the ground contact width was 105, whereas in the above example, the ground contact length formula was 184 mtx, and the ground contact width was 184 mtx, The width is now 106 mm, which is advantageous in reducing the steering force during excavation.

In addition, the cornering force and self-lining torque have the characteristics shown in Figure 3. That is, for example, in the case of a slip angle of 5 dog, the conventional value was 0 cornering force (kg) 2190 cells 7 aligning torque (g-m) 6.10 new automatic rail 2'Z9 However, in the above example, 0 cornering force (9 to ') 227 (104
)0 Self-aligning torque (kg・m) 5.9(
93) 0 pneumatic track (related) 25.1 (9
0) Tonashi ((0 is the index when the conventional tire is set as 100)), cornering force is essentially increased by 4%.

Cell 7 aligning torque has decreased by 7 inches, and pneumatic trail has decreased by 10 inches.

As a result, in addition to reducing the steering force during excavation described above, it is also possible to reduce the steering force when turning. kg) 9.3 and the next one is 0 stationary steering force (kg) 'Z9 (94) 0 lateral Gα5g in the above example.
The steering force (kg) at the time was 37 (94) ((() is an index when the conventional tire is set as 100)).

In addition, as mentioned above, the cornering force has increased in conjunction with the reduction in cell 7 aligning torque, so the third
As shown in the figure, when the slip angle is smaller than around the slip angle Q deg where the cell 7 aligning torque is maximum, the slip angle required to give the same cornering force can be set smaller, and the cell 7 aligning torque is more It will become smaller.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, by appropriately combining various conditions such as carcass material and strand strength, the rigidity of the carcass and eventually the trend part is increased, while the winding height of the carcass end at the bead part is increased. Due to the increased rigidity of the sidewall section,
By shortening the contact length relative to the contact width, the stationary steering force can be reduced, and while the cornering force increases, the cell 7 aligning torque decreases, which improves maintenance during turns. This has the effect that the rudder force can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a cutaway perspective view showing an embodiment of a bias tire according to the present invention, FIG. 2 is a half-sectional view of FIG. 1, and FIG. 3 is a relationship between slip angle, cornering force, and cell 7 aligning torque. FIG. 1... Trend, 3A, 3B... Carcass, 4.
...Bead part.

Claims (1)

[Claims] (1) By combining the carcass material, wire strength, cord angle, and number of cords, the bending rigidity of the tread part can be calculated in the circumferential direction from 1049 to 1171 kg・mj/
A bias tire having a weight of 777 to 795 kg·Nj/lII in a cross-sectional direction, and having a rolled-up height of at least one carcass end at a bead portion of 60 mm or more.