Patent Application
20190308469
The present invention relates to tire construction and specifically to a bicycle tire construction having a unique casing construction.
Modern bicycle tires are typically made with multiple casing layers that overlap to create the basic body of the tire. At least one of the casing layers wraps around bead cores on either edge of the tire to define the tire beads. A tread layer is positioned on the casing layers to provide a running surface in contact with the road. A breaker belt can be provided under the tread layer to improve puncture resistance of the tire.
The present invention provides a vehicle tire comprising first and second bead cores spaced apart from each other. A first casing layer (e.g., a base casing layer) spans between the bead cores and is wrapped around the bead cores. The first casing layer has first edge sections that do not overlap with each other and stop short of a central tread region of the tire. A second casing layer (e.g., an additional casing layer) has second edge sections that overlap the first edge sections of the first casing layer, and the second casing layer spans the central tread region. A tread layer spans the central tread region. Preferably, the second casing layer does not wrap around the bead cores.
The bead cores each preferably comprise a polymeric yarn bundle comprising aramid fibers or zylon fibers. The casing layers each preferably comprise a woven cloth including nylon, cotton, or silk. The tread layer preferably comprises butyl rubber and carbon black.
The tire can further comprise a breaker belt in the central tread region. In one embodiment, the breaker belt is positioned between the second casing layer and the tread layer, and in another embodiment the breaker belt is positioned between the first casing layer and the second casing layer.
In the disclosed tire construction, first and second sidewall regions are defined between the tread layer and the first and second bead cores, respectively. The sidewall regions comprise three plies of casing layers and the central tread region comprises two plies of casing layers. For example, the three plies can be made up of two plies of the first casing layer and one ply of the second casing layer, and the two plies can be made up of one each of the first casing layer and the second casing layer.
Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways.
The illustrated tires 14 have a unique layered construction using known materials. For example, the inside of the beads 16 include bead cores 24 made of wire or a polymeric yarn bundle, such as aramid, Kevlar, or Zylon fibers, or a mixed of those materials. The sidewalls 20 are formed by casing layers, described below, that similarly can be made of multiple different known casing materials, such as cloth comprising nylon, cotton or silk. Thread counts can vary, but generally are between 100 and 150 tpi. For airtightness, the casing cloth material can be embedded with rubber or resilient polymer, which is particularly beneficial when using the tire in a tubeless configuration.
The unique layered construction of the present invention can be implemented in multiple different configurations. For example, referring to
An additional casing layer 40 is sandwiched between the edge sections 34 and central section 32 of the base casing layer 30. That is, the additional casing layer 40 has edge sections 42 that overlap with the edge sections 34 of the base casing layer 30. The additional casing layer 40 extends between the bead cores 24, but does not wrap around the bead cores 24. In this regard, it can be seen that the additional casing layer 40 spans the central tread region 36. This additional casing layer 40 is a woven construction oriented at 45 degrees to the direction of travel.
A tread layer 50 is positioned above and spans the central tread region 36 of the tire 14. The illustrated tread layer 50 overlaps the edge sections 34 of the base casing layer 30 by about 5-7 mm. The tread layer 50 can be made of any suitable material, such as butyl rubber mixed with carbon black and/or silicon, as is known in the art.
The illustrated tire 14 further includes a breaker belt 60 in the central tread region 36 between the tread layer 50 and the additional casing layer 40. The breaker belt 60 provides a cut-resistant layer, and can be made of a suitable mesh made from aramid, Kevlar, or Zylon and positioned at an angle of 45 degrees to the direction of travel. As shown in
Referring to
The above-described tire construction provides a tire 14 having sidewalls 20 with three plies of casing layers and a central tread region 36 with two plies of casing layers. More specifically, the three plies of each sidewall 20 are made up of two plies of the base casing layer 30 (i.e., the center section 32 and the edge sections 34) and one ply of the additional casing layer 40. The two plies of the central tread region 36 are made up of one each of the center section 32 of the base casing layer 30 and the additional casing layer 40. This arrangement is believed to provide low rolling resistance (due to the two-layer central tread region) combined with excellent cornering performance and sidewall integrity (due to the three-layer sidewall regions).
Various features and advantages of the invention are set forth in the following claims.
