Resilient tires and wheels – Tires – resilient – Anti-skid devices
Reexamination Certificate
1998-12-03
2003-09-16
Maki, Steven D. (Department: 1733)
Resilient tires and wheels
Tires, resilient
Anti-skid devices
C152S209800, C152S209900, C152S209180, C152S209220, C152S209230, C152SDIG003
Reexamination Certificate
active
06619352
ABSTRACT:
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. §119 of German Patent Application No. 197 53 819.3, filed on Dec. 4, 1997, the disclosure of which is expressly incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a tread profile of a snow tire.
2. Discussion of Background Information
Various and conflicting demands are placed on snow tires. That is, a snow tire is supposed to ensure good traction on snow and ice and good handling characteristics, e.g., as in summer tires. However, these demands require conflicting measures in the design of the snow tire, i.e., to provide either a snow tire with either good winter characteristics, e.g., good traction on ice and snow and comparatively poor handling on dry roads, or a summer tire with good handling on dry roads, but comparatively poor winter characteristics.
SUMMARY OF THE INVENTION
The present invention provides a tread profile for a snow tire with both good winter characteristics, e.g., good traction on ice and snow, and good handling on dry roads.
The present invention contemplates a tread profile that includes a plurality of profile block rows aligned in a circumferential direction and spaced in an axial direction from a first tire shoulder, adapted to be positioned toward an outside of the vehicle in an operating state of the tire, to a second tire shoulder, adapted to be positioned toward an inside of the vehicle in an operating state of the tire, and a plurality of channels aligned in the circumferential direction and arranged to axially separate the plurality of profile block rows from each other. The plurality of channels includes a first circumferential channel positioned to divide the tread profile into two axial regions of functionally different structure. Each axial region axially extends from an associated tire shoulder to the first circumferential channel. The profile block elements in the axial region extending from the first circumferential channel to a first tire shoulder directed away from the vehicle during an operating state of the tire are constructed with a higher lateral thrust stiffness than the profile block elements in the axial region extending from the first circumferential channel to a second tire shoulder pointing toward the inside of the vehicle in the operating state of the tire on the vehicle.
As a result of the stiffer construction of the profile block elements on the side of the tread profile pointing toward the outside of the vehicle, the stiffness desired for handling may be substantially ensured on this side of the tire (i.e., the handling side), which is important for handling, and, therefore, good handling on dry roads is provided. In the axial tread region that is less important for handling (i.e., the winter side), the low stiffness of the profile blocks that is important for good traction on snow and ice are provided, and, therefore, good winter traction is substantially ensured.
In the exemplary embodiment of the present invention, it may be preferable to arrange the profile blocks such that the profile blocks in the axial region directed toward the inside of the vehicle have structural factors, both along a circumferential direction and perpendicular to circumferential direction, between approximately 10 and 50% higher than the structural factors of the profile blocks in the axial region directed toward the outside of the vehicle. Thus, an especially high number of traction edges may be created on the winter side. Further, a large number of sipes, which are substantially responsible for the structural factor, may make the profile blocks even softer on the winter side. Conversely, the handling side may be stiffer due to the lower number of the sipes creating the traction edges. The structural factor in the circumferential direction is a sum of the profile block edges and sipes projecting in the circumferential direction, and the structural factor in the direction perpendicular to the circumferential direction is the sum of the profile block edges and sipes projecting perpendicular to the circumferential direction.
The exemplary embodiment may also preferably include a pitch count in the axial region directed toward the inside of the vehicle that may be greater than pitch count in the axial region directed toward the outside of the vehicle. As a result of this construction, more and smaller profile elements may be created on the winter side of the tire than on the handling side of the tire. Thus, even more profile edges may be provided for facilitating winter taction. As a result of this feature, the handling side may also be more stiffly constructed.
Free visibility through a circumferential groove is a measure of ice traction and snow traction. As a result, the tire of the present invention may be formed such that at least one additional circumferential channel or groove may be provided in both axial regions to separate two adjacent profile block rows from one another. It may be preferable to form the at least one additional circumferential channel in the axial region directed toward the vehicle to have an exposed groove cross-section that is smaller than the exposed groove cross-section of the at least one additional circumferential channel in the axial region directed toward the outside of the vehicle. It may be preferable still to provide the exposed groove cross-section of the at least one additional circumferential channel in the axial region directed toward the vehicle with a width that is at least half as large as the exposed groove cross-section of both the first circumferential channel and/or the at least one additional circumferential channel in the axial region directed toward the outside of the vehicle. In this manner, the tire of the present invention may exhibit further improvement over known tires in ice traction characteristics and in braking characteristics on snow without jeopardizing handling characteristics on dry roads.
The profile block elements on the winter side of the tire may include a plurality of sipes that extend through the profile block elements, and it may be preferable to arrange the sipes such that a distance between a peripheral edge of a respective profile block element and an adjacently arranged sipe arranged within the respective profile block element is between approximately 7 and 15% greater than a distance between the substantially parallelly arranged sipes arranged within the respective profile block element. Further, it may be preferable to provide a sipe depth at the edges of the profile block element that is between approximately 10 and 20% smaller than in a region between the edges of the profile block, i.e., in the interior of the profile block element. Thus, the profile block elements may be constructed with a hard, wear-reducing shell outside and a soft core inside that improves winter characteristics.
The exemplary embodiment of the present invention may preferably include at least one profile block row formed by successively arranged profile block elements in the circumferential direction that are separated by diagonally running channels forming transverse edges to define the profile block elements in the circumferential direction, that include longitudinal edges to laterally define the profile block elements, and that include spaced sipes that extend through the profile block element at an angle between approximately 80 and 110° to the longer diagonals of a trapezoid formed by the transverse edges and the longitudinal edges. This particular arrangement may make possible a particularly high effective edge length in the profile block elements. Further, the exemplary embodiment may preferably include, at the tire shoulders and in at least one profile block row arranged between the tire shoulders, profile block rows formed by successively arranged profile block elements in the circumferential direction that are separated by diagonally running channels forming transverse edges to define the profile block ele
Diensthuber Franz
Peschel Wolfgang
Continental Aktiengesellschaft
Greenblum & Bernstein P.L.C.
Maki Steven D.
LandOfFree
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