Resilient tires and wheels – Tires – resilient – Pneumatic tire or inner tube
Reexamination Certificate
1999-12-02
2001-08-21
Johnstone, Adrienne C. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Pneumatic tire or inner tube
C152S553000, C152S554000, C152S555000
Reexamination Certificate
active
06276418
ABSTRACT:
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a pneumatic radial tire, more particularly to a pneumatic radial tire having driving stability and load durability applicable to a high performance passenger vehicle.
[0002] Conventionally, as a radial tire for a high performance passenger vehicle, for example, a pneumatic radial tire has been known in which the carcass layers are a two-layer structure as shown by FIG.
2
. According to the tire shown by
FIG. 2
, two carcass layers
28
and
30
are arranged to reach a bead portion
26
from a tread portion
22
via a side portion
24
. Whereas both end portions of the carcass layer
28
on an inner side are respectively folded back from an inner side of the tire to an outer side of a tire to wrap the bead fillers
34
around left and right bead cores
32
, both end portions of the carcass layer
30
on an outer side are turned down to vicinities of bead toes via inner diameter sides of the bead cores
32
to cover outer sides of fold back portions
28
b
of the carcass layer
28
. Further, reinforcement layers
36
comprising steel cords are arranged between the carcass layer
30
on the outer side and fold back portions
28
b
of the carcass layer
28
on the inner side. Further, two belt layers
38
are arranged on an outer side of the carcass layer
30
on the outer side at the tread portion
22
.
[0003] In viewing passenger vehicles on sale in recent years, a vehicle having a power output of 280 horsepower and a mass of 1.5 tons has become more common than a vehicle having a displacement of 2000 cc. In the case of the conventional tire structure shown by
FIG. 2
, it is difficult to ensure driving stability and load durability for such a vehicle. However, when widths of reinforcement layers of a tire are uselessly widened or a number of the layers is increased, a problem can occur in which not only is there an increase in the tire mass but also the load durability deteriorates.
SUMMARY OF THE INVENTION
[0004] It is an object of the invention to provide a pneumatic radial tire capable of promoting driving stability and load durability applicable to a high performance passenger vehicle without substantially giving rise to an increase in the mass of the tire.
[0005] In order to achieve the above-described object, according to an aspect of the invention, there is provided a pneumatic radial tire comprising three plies of carcass layers in which the respective plies comprise organic fiber cords and cord angles of the respective plies relative to a peripheral direction of the tire fall in a range of 65 degrees through 90 degrees, wherein both end portions of a first one and a second one of the carcass layers enumerated from an inner side to an outer side direction of the tire in the three plies of the carcass layers, are folded back from the inner side to the outer side of the tire respectively around bead cores, reinforcement layers are arranged on outer sides of fold back portions of the carcass layers and a third one of the carcass layers is turned down to cover outer sides of the reinforcement layers.
[0006] According to the invention, as mentioned above, three plies of the carcass layer comprising organic fiber cords are provided, the first and the second carcass layers are folded back from the inner side to the outer side of the tire around the bead cores, the reinforcement layers are arranged on the outer sides of the fold back portions, the third carcass layer is turned down on the outer sides of the reinforcement layers. Accordingly, even when a total denier of the organic fiber cords of a total of the carcass layers is made equivalent to that of a conventional pneumatic radial tire for a high performance passenger vehicle using two layers of carcass layers, promotion of higher driving stability and load durability can be achieved. Accordingly, the driving stability and the load durability applicable to a high performance passenger vehicle, such as those on sale in recent years can be achieved.
[0007] In this case, “turning down the third carcass layer to cover the outer side of the reinforcement layer” means that the third carcass layer is arranged to hang down to reach the vicinities of the bead toes from the outer sides of the reinforcement layers via the inner diameter sides of the bead cores.
REFERENCES:
patent: 4024901 (1977-05-01), Poque
Arent Fox Kintner & Plotkin & Kahn, PLLC
Johnstone Adrienne C.
The Yokohama Rubber Co. Ltd.
LandOfFree
Pneumatic radial tire with turned down carcass layer does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pneumatic radial tire with turned down carcass layer, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pneumatic radial tire with turned down carcass layer will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2544620