Patent Application
20060124221
The present invention relates to pneumatic tires and, more specifically, to truck trailer tandem tire systems in which the trailer tires have a ply carcass construction.
Conventional truck trailer tires have a carcass construction extending between two wheel rim contacting bead portions through sidewall portions to a ground contacting tread portion. The tire carcass is conventionally reinforced by one or more plies of cord reinforced tire fabric extending continuously from bead to bead.
The ground contacting tread region is further reinforced between tread edges by a circumferentially extending annular belt package comprising a plurality of plies of cord reinforced rubber fabric disposed radially outwardly of the carcass ply and inwardly of the tread rubber. Truck tire construction common in the industry is representatively shown in the form of a super single tire configuration in U.S. Pat. No. 6,619,357.
In practice, it is common to mount dual trailer tires on a common axle side where the two tires operate in tandem as a free-rolling dual assembly. However, in such a configuration, a problem arises as each free-rolling tire in a tandem pair is at odds with and fights against the mating dual tire. While one tire is torquing up, the mate is experiencing increasing negative torque to the detriment of tire performance. Such a consequence is due to a number of factors such as slightly different rolling tire diameters between the dual tires; different inflation levels between the two tires; and/or different road crown conditions that each tire encounters. As a result, for long haul trailer applications, tire free-rolling torque issues may be responsible for higher rates of wear for both tires in the dual assembly.
Consequently, the industry is in need of a dual tire assembly and mounting method that will minimize free-rolling torque interaction between the tires in an assembly. A solution to the industry's needs, ideally, would accomplish such an objective without requiring that tires in a dual assembly be manufactured in a cost prohibitive manner or requiring that special modifications to the trailer wheel axle be made. Moreover, an ideal solution to the industry's needs would result in improved tire wear rates for both tires in a dual tire assembly.
The subject invention according to one aspect relates to an improved dual tire assembly for a trailer in which two tires are proximally mounted in a free rolling side by side relationship. Each tire is constructed having the tire carcass slightly angled away from the conventional ninety degree configuration common to trailer tires to minimize torque windup and therefore reduce the degree to which the individual tires in a dual assembly fight each other. Such a deviation from ninety degrees is made relatively small enough to avoid experiencing a significant rolling resistance penalty in each tire yet large enough so that the torque windup effect of one tire on the other tire is minimized. Increased levels of tread wear are thus achieved.
Pursuant to another aspect of the invention, a method of reducing torque windup in a dual tire assembly is achieved comprising the steps: configuring both tires in a dual assembly to provide a carcass angled slightly from ninety degrees; mounting such tires in proximal relationship in a dual tire assembly on a common axle; operating both tires in a free rolling mode of operation; and using the angled carcass of each tire to minimize the effect of torque windup imposed by the opposite tire.
Pursuant to yet another aspect of the invention is to minimize the effect of torque windup in a free rolling dual tire assembly through the configuring of each tire in the dual assembly to have a tire carcass angled to the preferred deviation from ninety degrees.
As used herein and in the claims, the terms
The invention will be described by way of example and with reference to the accompanying drawings in which:
With reference to
The crown reinforcing structure 27 pursuant to conventional construction common in the art may comprise multiple spliced belts plies 18, 20, 22, and 24 reinforced with steel cords. The plies 18-24 may be reinforced with steel cords making an angle with respect to the equatorial plane (EP). Practice of the subject invention is not dependent on any particular crown reinforcing structure and any structure 27 in the art suitable for use in free rolling dual tire assemblies may be utilized. In the illustrated embodiment, the steel cords of the belt plies 18-24 have steel cord construction commonly used in the truck tire belt ply reinforcement field. The steel grades are high tensile.
As seen from
In order to ameliorate the torque windup caused by interaction between the two tires in a dual assembly, the subject invention employs tires in the dual assembly having a slightly angled carcass (as opposed to conventional 90 degree carcass constructions) in the crown region. The deviation angle of the tire carcass in each tire of a dual assembly is preferably relatively small, in the range of 0.5 to 10 degrees. Five degrees is shown in the tire of
Variations in the present invention are possible in light of the description of it provided herein. While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention. It is, therefore, to be understood that changes can be made in the particular embodiments described which will be within the full intended scope of the invention as defined by the following appended claims.
