Patent ID: 12240278

DETAILED DESCRIPTION

FIG.1shows an agricultural machine in form of a tractor10comprising tires20, each attached to a respective wheel hub25supporting a chassis, together with a pressure supply system30, which comprises at least a pump40and a rotary union50. The tires20are connected to the pressure supply system30of the tractor10via the rotary union50, which provides a seal between a stationary supply passage connected to the pressure supply system30, and fluid guiding components. The rotary union50is connected and rotating with the tire20, to permit the flow of a fluid, typically hydraulic oil, into and/or out of the rotating part.

FIG.2shows a tire20having a tread140, a bead170, a sidewall110, a carcass100(as shown inFIG.4), a shoulder150, and a first cavity180(as also shown inFIG.4). The first cavity180comprises a volume with which the tire20is filled. The tread140is the shaped outer periphery of the tire20, which comes into contact with the ground surface. The portion of the tread140that is in contact with the ground at a given moment is the contact patch90. The tire bead170secures the tire20to the wheel hub25, which is shown inFIG.1. The sidewall110is the part of the tire20that bridges between the tread140and the bead170. The carcass100, indicated generally inFIG.4, is the general structural component of the tire, giving a strengthening layer providing strength in the sidewall area110and support for the tread140across the area between the sidewalls110. The bead170has a bead toe130on the inner edge and a bead heel160on the outer edge (as shown inFIG.4A).

Stiffening lines70are arranged inside of the carcass100of the tire20and in the embodiment shown are firmly attached to the inner side of the carcass100by vulcanization. The stiffening lines70are aligned in a generally transverse direction with regard to the periphery of the tire (that is to say they lie in a plane that includes the axis of the wheel hub25on which the tire20is mounted) and extend inside of the carcass100along the side walls110and the tread140of the tire20. Each stiffening line70is an elongate hollow body comprising a second cavity190as shown inFIG.4. The shown tire20(with the exception of the stiffening lines70) may be, for example, of size 900/65R46, as is used on farm machinery such as the Fendt 1000 Vario tractor, which tire has an air volume of up to around 1900 liters in the first cavity180. To adjust the stiffness of the tire20and its contact patch90, the second cavity190of the stiffening lines70may be filled. The comparatively small volume (of around 20 liters) of the second cavity190is quickly filled with pressurized fluid, in this case a hydraulic oil, by the pump40of the tractor pressure supply system30, which tractor pressure supply systems can typically deliver up to 240 liters per minute. As will be understood, the number of stiffening lines70deployed around the periphery of the tire20may depend on the dimensions of the tire20; for example twenty-four (24) stiffening lines70, as displayed inFIG.5, could be used for the above-mentioned 900/65R46 tire size.

FIG.4shows a sectional view ofFIG.2taken on the line indicated with A-A.FIG.4shows the tire20with its first cavity180and one of the attached stiffening lines70with its second cavity190. The second cavity190, which is aligned in a transverse direction across the periphery of the tire20extends along the side wall110, along the curvature of the shoulder150, and across the interior portion of the tread140of the tire20. As mentioned above, the second cavity190suitably lies generally along a plane that includes the axis of the wheel hub25on which the tire20is mounted), but the second cavity190may have a slight angular offset from this planar alignment (e.g., by 3°, 5°, 7°, or 10°).

The part of the tread140that is in direct contact with the ground is the contact patch90. In a field working mode, the stiffening lines70are depressurized and the pressure in the second cavities190may be released to atmosphere. The stiffening lines70are in a pressure free state so that the walls of the stiffening lines70are soft and pliable, enabling a large contact patch90with a low tire pressure. In a street travelling mode, a high tire pressure and a small tire contact patch90is desirable. Accordingly, the stiffening lines70are filled with the pressurized fluid supplied by the pump40(FIG.1) to a high pressure (e.g., 160 bar, 200 bar, 240 bar, etc.) as compared to a typical first cavity pressure in road travelling mode of, for example 2.4 bar. The stiffening lines70therefore become relatively unyielding and produce a stiffer carcass100, providing a smaller tire contact patch90.

FIG.4Ashows the stiffening lines70and the second cavity190in more detail (the circled portion indicated at X inFIG.4). The pressure supply system30(FIG.1) supplies the pressurized fluid, which is delivered to the stiffening lines70via the rotary union50(FIG.1) and a line connection point. The line connection point is in fluid communication with the supply line80(FIG.1). If the pump40of the pressure supply system30can deliver up to about 240 liters per minute and the second cavity190defined by the stiffening lines70only holds a volume of about 20 liters, the stiffening lines70can be pressurized within seconds.

FIG.5shows an arrangement in which all stiffening lines70are connected to each other with a single supply line80, so they can be pressurized quickly. The supply line80extends along the bead toe130on the inside of the tire20and is fixed there in like manner to the attachment of stiffening lines70. Alternately, the supply line80can consist of two pieces, which are concentric to the wheel axis and are connected to various of the stiffening lines70hydraulically with a T-shaped connection. Further alternately, an ancillary supply line portion may run around the bead toe on the opposite side of the tire to the first bead toe and link together the distal ends of stiffening lines70extending from the first supply line.

Referring additionally toFIG.6, connected to the rotary union50via a supplementary supply line or hose79, the supply line80supplies all the stiffening lines70conjointly with the pressurized hydraulic oil. A controlling element81in form of an electromagnetic closing valve or similar may seal the stiffening lines70when pressurized, such that the rotary union50need not be under pressure during the whole usage of the stiffening lines70. This can reduce the risk of damages, for example through wear. The controlling element81is in fluid connection with the supply line80via the supplementary supply line or hose79and therefore also the stiffening lines70and can be located on the tire20. For example, the supply line or hose79may be fixed to the rim or within the first cavity180of the tire20. With the above-described arrangement, the pressure of all stiffening lines70and therefore also the stiffness of the tires20may be adjusted substantially simultaneously, and at a more efficient rate while the tractor10is still in operation (i.e., travelling on a first road/field terrain and about to transition to a second field/road terrain).

A stiffening line70may be a fluid hose or tube attached to the inner side of the tire carcass100and which is capable of being pressurized. In other embodiments, the stiffening line70can be any suitable structure capable of holding pressurized fluid, and may, for example, be integrated into the carcass100of the tire20.

An advantage of the tire20described herein compared to the state of the art is the ability to change the stiffness of a tire20very quickly. For comparison, a commonly used tire-pressure adjustment device would take up to fifteen (15) minutes to increase the pressure of a tractor working tire, for example from 0.8 bar (field working mode) to 2.4 bar (road travelling mode). The tire20with the installed stiffening lines70can provide increased stiffness in seconds, because of the small volume of the second cavity190, which holds only a relatively small volume, such as from about 10 liters to about 50 liters. This results in the relatively fast pressurizing of the stiffening lines70and therefore the fast adjustment of the tire20stiffness and therefore a significant reduction of the waiting time. The tires20can provide a better grip, traction, and movement of the tread140with a larger contact patch90when needed, and also a greater fuel economy due to a smaller contact patch90when travelling on a road, yet avoid excessive delays for transitions.

All references cited herein are incorporated herein in their entireties. If there is a conflict between definitions herein and in an incorporated reference, the definition herein shall control.

While the present disclosure has been described herein with respect to certain illustrated embodiments, those of ordinary skill in the art will recognize and appreciate that it is not so limited. Rather, many additions, deletions, and modifications to the illustrated embodiments may be made without departing from the scope of the disclosure as hereinafter claimed, including legal equivalents thereof. In addition, features from one embodiment may be combined with features of another embodiment while still being encompassed within the scope as contemplated by the inventors. Further, embodiments of the disclosure have utility with different and various machine types and configurations.