CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of each of: U.S. Provisional Application S.N. 61/924,646, filed on January 7, 2014; U.S. Provisional Application S.N.

61/931 ,916, filed on January 27, 2014; and U.S. Provisional Application S.N.

61/978,422, filed on April 1 1 , 2014, each of which is incorporated by reference herein in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0002] This invention was made with Government support under DE-EE0005447 awarded by the Department of Energy (DOE). The Government has certain rights in this invention.

BACKGROUND

[0003] A self-inflating tire system can use a pump that is built into a tire to automatically maintain a vehicle's tire pressure at a target pressure. A pneumatic control valve can sense when the tire is at the target pressure. If the pressure drops below the target level, an inlet filter in the pneumatic control valve can allow some outside air into the pumping tube which runs circumferentially around the inside of the tire. Deformations of the tube as the tire rolls can compress air inside the tube. The air can be discharged through the pneumatic control valve into the pressurizable tire space to inflate the tire.

SUMMARY

[0004] A tire air intake filter includes a housing to be attached to a sidewall of a self-inflating pneumatic tire. The housing has a cavity to be in fluid communication with an atmospheric air inlet of a pneumatic control valve for the self-inflating tire. A filter media can block contaminants from entering the cavity while allowing

atmospheric air to be drawn through the filter media into the cavity by a pump of the self-inflating tire. The filter has an elliptical profile having a minor axis and a major axis. The minor axis can be aligned with a radius of the tire. A self-inflating tire having the air intake filter is also disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] Features and advantages of examples of the present disclosure will become apparent by reference to the following detailed description and drawings, in which like reference numerals correspond to the same or similar, though perhaps not identical, components. For the sake of brevity, reference numerals or features having a previously described function may or may not be described in connection with other drawings in which they appear.

[0006] Fig. 1 is a perspective view of an example of an intake filter of the present disclosure;

[0007] Fig. 2 is a left side view of the example of the intake filter depicted in Fig. 1 according to the present disclosure;

[0008] Fig. 3 is a cross-sectional view of the example of the intake filter, taken along line 3-3 in Fig. 2;

[0009] Fig. 4 is an end view of a wheel and tire with an example of an intake filter disposed thereon according to an example of the present disclosure;

[0010] Fig. 5A is a cross-sectional view of a wheel and tire depicting a pneumatic control valve disposed on the tire according to an example of the present disclosure;

[0011] Fig. 5B is a cross-sectional view of an example of a filter media according to the present disclosure;

[0012] Fig. 6 is a semi-schematic, cut-away cross-sectional view of an example of an intake filter on a tire according to the present disclosure;

[0013] Fig. 7 is a perspective cut-away view of a wheel and tire depicting an example of an intake filter of the present disclosure; and [0014] Fig. 8 is a perspective exploded view depicting an example of an intake filter according to the present disclosure.

DETAILED DESCRIPTION

[0015] The present disclosure relates generally to an intake filter for an air pump. Such a filter can be used, for example, with a self-inflating tire system used with the tires of a commercial truck. It is to be understood that intake filters according to the present disclosure can be used with various sizes of tires for various types of vehicles.

[0016] Figs. 1 , 2 and 3 depict an example of an intake filter 17 of the present disclosure. Clean (filtered) air can be communicated from the intake filter 17 through inlet port 83, via inlet 22 to an intake of a pneumatic control valve 10 (see Fig. 8) for a pneumatic tire 50 in a self-inflating tire system 180. The pneumatic control valve 10 can regulate airflow into and out of a pump (not shown) and thereby regulate air pressure in the pneumatic tire 50. The example of the intake filter 17 depicted in Figs. 1 , 2 and 3 can include a housing 12, and a filter media 16. As used herein,

environment can be defined to mean ambient air including any contaminants present (e.g., dirt, dust, road debris, mud, water, other fluids and particulate matter, etc.).

Also, outside can be defined to mean the space that is not enclosed by the tire 50 or the intake filter 17. Tires 50 operating in the environment are subjected to various contaminants in various forms. For example, a cloud of dust can envelop the tire 50. In other examples, a tire 50 can travel through rainy conditions or through puddles of dirty water or mud, creating a splash or cloud of contaminants from operation of the tire 50, or from operation of another tire nearby. The tire that causes the splash or cloud can be on the same vehicle as the intake filter 17, or on another vehicle.

[0017] The intake filter 17 can include a snap-on filter cover 19 disposed adjacent to the filter media 16. In an example, the housing 12 can have an elliptical profile. The intake filter 17 can be any size with sufficient airflow capacity to allow the self- inflating tire pump to operate without significant restriction to the airflow. An example of significant restriction can be in a range from about 10 inches of water to about 30 inches of water or greater pressure drop at the maximum flow rate through a clean, dry filter. In an example, the major axis 67 of the ellipse can be about 3 cm, and the minor axis 59 can be about 1 cm. In other words, the ellipse, measured along the major axis 67, can be about 3 cm, and the ellipse, measured along the minor axis 59 can be about 1 cm. In another example, the intake filter 17 can be an ellipse with a major axis 67 ranging from about 20 mm to about 50 mm, a minor axis 59 ranging from about 5 mm to about 20 mm, and a depth 170 ranging from about 5 mm to about 15 mm. In an example, an area of filter media exposed to the outside environment ranges from about 50 square mm (millimeters) to about 100 square mm.

[0018] The intake filter 17 can be embedded in a tire sidewall 171 . For example, the intake filter 17 can be molded in place in the tire sidewall 171 (see, e.g., Fig. 6), or installed into a complementary shaped elliptical socket 31 (see, e.g., Figs. 6 and 8) in the sidewall 171 . Without being bound to any theory, it is believed that radial strains are larger in some tire sidewalls than tangential strains. The elliptical shape of the intake filter 17 disclosed herein reduces stresses in the tire 50 and on the intake filter 17. By aligning the minor axis 59 of the elliptically shaped intake filter 17 with a radius of the tire 50, the radial load applied by the tire 50 on the intake filter 17 is minimized. It is also believed that by aligning the minor axis 59 of the elliptically shaped intake filter 17 with a radius of the tire 50, stress risers in the sidewall 171 from the intake filter 17 can be minimized.

[0019] In examples of the present disclosure, the snap-on filter cover 19 can be made of a flexible material, or the snap-on filter cover 19 can be substantially rigid. The snap-on filter cover 19 can be attached to the housing 12 to retain the filter media 16 and to allow air to flow through the filter media 16.

[0020] As shown, for example, in Fig. 4, the housing 12 can be accommodated on, or fitted in a sidewall of a pneumatic tire 50 for connection to a pneumatic control valve 10 (see Fig. 8) inside the tire 50. The housing 12 can be molded into the sidewall of the tire 50 during the production process of tire 50. Other attachment mechanisms will be discussed further below.

[0021] Fig. 5A is a cross-sectional view of a wheel 98 and tire 50 depicting an example of the air regulator 120, including pneumatic control valve 10 and docking station 100, mounted to the tire 50 according to an example of the present disclosure. The air regulator 120 is fixedly attached to the tire 50 and at least a portion of the pneumatic control valve 10 is disposed within the pressurizable tire space 52.

[0022] It is to be understood that the mass of air pumped into the pressurizable tire space 52 (see Fig. 5A) by the pump (and therefore through the intake filter 17) according to the present disclosure in a single revolution of the wheel 98 can be relatively small compared to the mass of air in a fully inflated tire 50. In an example, a self-inflating tire system 180 can pump enough air to make up for normal losses in the tire 50. For example, a self-inflating tire system 180 can pump about one psi into a 100 psi tire over a month. A range of airflow from about 250 SCCM (Standard Cubic Centimeters per Minute) to about 1000 SCCM can flow through the intake filter 17. In terms of mass airflow, the same example would range from about 0.3 g (gram) to about 1 .3 g of dry air at STP (Standard Temperature and Pressure). In an example, a commercial truck tire can contain 150 liters of air at about 100 psi (689 kilopascals) under normal operating conditions.

[0023] The filter media 16 can be disposed in contact with the snap-on filter cover 19 of the intake filter 17. As depicted in Fig. 8, the cavity 26 is in fluid communication with the inlet port 83 providing air to the pump via the pneumatic control valve 10 of the tire 50. The filter media 16 can block contaminants from entering the cavity 26 while allowing atmospheric air to be drawn through the filter media 16 into the cavity 26 by a pump of the self-inflating tire system 180. In an example, the filter media 16 can substantially block contaminants from entering the cavity 26 while allowing a small amount of contaminants to pass through the filter media 16. As used herein, substantially block can be defined to mean contaminants in the form of particulate matter will be blocked if the particulate matter is larger than a predetermined size. For example, the efficiency of the filter media 16 can be at least about 90 percent when exposed to 150 grams of dust at a maximum flow rate using SAE J726 JUN2002, Air Cleaner Test Code, Section 5.4. After exposure to the dust, the pressure drop across the filter is within about 70% of the pressure drop at clean filter conditions. Pressure drop is measured at maximum flow rate. The pressure drop across a clean intake filter 17 can be less than about one psi when measured at maximum flow rate. It is to be understood that the pump is operatively connected to the pneumatic control valve 10.

[0024] A membrane can be used as a filter media 16 to block water or other contaminants. As used herein, membrane can be defined to mean a layer of material which serves as a selective barrier between two phases (e.g., liquid water and vapor) and remains impermeable to specific particles, molecules, or substances when exposed to the action of a driving force. The membrane, in an example, can be about 0.5 mm thick and can be fixed to the snap-on filter cover 19 with an adhesive. In another example, the membrane can be attached to the snap-on filter cover 19 by welding (e.g., heat stake).

[0025] Referring to Fig. 5B, the filter media 16 can have a single layer, or include a plurality of layers. Fig. 5B depicts an example of a filter media 16 having a first filter layer 182, a second filter layer 183, and a third filter layer 184. Other examples can have more layers, or fewer layers. The filter media 16 can include a membrane layer; woven fiber layer; a non-woven fiber layer; a reticulated foam layer; an activated carbon layer; a porous solid layer; or any combination thereof in overlying relationship. Examples of fiber layers can include a polytetrafluoroethylene (PTFE) fiber (e.g., Teflon® fiber, available from E. I. du Pont de Nemours and Company, Wilmington, Delaware) and/or can include expanded polytetrafluoroethylene (ePTFE) (e.g., Gore- Tex® brand materials, available from W. L. Gore & Associates, Inc., Elkton, Maryland). Examples of the porous solid layer can include compressed carbon charcoal. In an example, the filter media 16 can include a layer of activated carbon disposed between two woven fiber layers. An example of a membrane layer can include a non-woven nylon/polyamide, e.g., Versapor ^® 450R from Pall.

[0026] Referring now to Fig. 6, the intake filter 17 is depicted as fitted in the sidewall 171 of tire 50. Loading of the tire 50 through the wheel 98 (see Fig. 5A) can compress the tire 50 against the road surface 40, causing deflection of at least a portion of the tire 50. Under load, the tire 50 can form a contact patch on the road surface 40 to distribute the load from the tire 50 to the road surface 40. As used herein, the contact patch can be defined to mean the total area of the tire tread in contact with a road surface, including the area of grooves or other depressions and can be load and inflation dependent. As used herein, road surface 40 (see Fig. 4) can be defined to mean any surface upon which a tire 50 attached to a vehicle is operated. For example, a road surface 40 can be paved, unpaved, dirt, mud, sand, cinders, gravel, clay, stone, concrete, tarmac, macadam, paint, rubber, plastic, wood, metal, expanded metal, glass, ice, snow etc., and combinations thereof. Fig. 6 depicts the connection of intake filter 17 via inlet port 83 and inlet 22 through a sidewall of the tire 50 to the pneumatic control valve 10.

[0027] The intake filter 17 can, under certain conditions, receive a flow of air from the pneumatic control valve 10 to pass in turn from the cavity 26 through the filter media 16 to clean the filter media 16. As such, the intake filter 17 can be self-cleaned by reversing the direction of airflow through the filter 17. The self-cleaning can occur periodically, e.g., with every revolution of the tire 50 as long as the air inspired in that revolution is not used during the revolution to fill the tire 50.

[0028] In examples of the present disclosure, the intake filter 17 assembly can be modular, thereby allowing simple replacement of the filter media 16. In an example, the filter media 16 can be replaceable without permanently disabling a portion of the intake filter 17 other than the filter media 16 to be replaced. For example, the housing 12 can be permanently fixed in the tire 50, e.g., by a molding and curing process;

whereas the snap-on filter cover 19 can be removable to provide access to the filter media 16 for replacement.

[0029] As shown in Fig. 6, slots 62 of lock pan 172 can engage retention feature 64 of the lock pan 172. The housing 12 has respective access openings 173 to allow access to the retention feature 64. As depicted in Fig. 6, the retention feature 64 can be a resilient tab 178, interoperable with slot 62 to deform and enter the space created by slot 62 to form a snap lock between the snap-on filter cover 19 and the lock pan 172. The resilient tab 178 can further engage the access opening 173. Alternatively, the retention feature 64 can be stiffer than the lock pan 172 and the housing 12, and therefore the lock pan 172 and the housing 12 can deform around retention feature 64 during assembly. The snap retention of the snap-on filter cover 19 onto the lock pan 172 and the housing 12 can allow retention without separate fasteners, ease assembly, and facilitate serviceability of the intake filter 17. The removable snap-on filter cover 19 can allow the filter media 16 to be replaced without destroying the intake filter 17.

[0030] Fig. 7 is a perspective cut-away view depicting an example of an intake filter of the present disclosure. Fig. 8 is a perspective exploded view depicting an example of an intake filter 17, tire 50, docking station 100 and pneumatic control valve 10 of a self-inflating tire system 180 according to an example of the present disclosure.

[0031] Referring to Figs. 7 and 8 together, the filter media 16 can be disposed between the snap-on filter cover 19 and the housing 12. The snap-on filter cover 19 can define at least one aperture 32 to expose the filter media 16 to the atmosphere 84 impinging upon the tire 50. The at least one aperture 32 also can be used as removal tool access points for removing the snap-on filter cover 19 from the intake filter 17 for servicing or replacing the filter media 16. Retention features 64 can be tabs that engage slots 62. The snap-on filter cover 19 can have at least one aperture 32 defined therein to operate as an intake screen 18. The intake screen 18 can protect the filter media 16 from impacts and abrasion prior to and during installation in the tire 50, as well as from large pieces of debris that can contact the snap-on filter cover 19.

[0032] The at least one aperture 32 can be aligned with a direction of a flow stream of water that is induced by rotation of the tire 50 to cause the flow stream to wash debris from the at least one aperture 32. The aperture can be a passage 174 oblique to a radius 175 of the tire 50. A centrifugal force 176 induced by the rotation of the tire 50 can urge water (not shown) out of the passage 174 away from the filter media 16. The walls 177 of the snap-on filter cover 19 can block a line-of-sight through the passage 174 to the filter media 16.

[0033] The intake filter 17 can be installed in the complementary shaped elliptical socket 31 formed in the sidewall 171 of the tire 50. The snap-on filter cover 19 can snap into the lock pan 172 with the filter media 16 therebetween. In the example depicted in Figs. 7 and 8, four resilient tabs 178 can snap into slots 62 defined in the lock pan 172. A filter sub-assembly 179 including the snap-on filter cover 19, the filter media 16 and the lock pan 172 can be snapped into the housing 12. Portions of the resilient tabs 178 can extend through the slots 62 to engage the access openings 173 in the housing 12. In the example depicted in Figs. 7 and 8, the intake filter 17 can include the filter sub-assembly 179 and the housing 12. A resilient cover strip 181 can form a seal between the housing 12 and the tire sidewall 171 . Peristaltic pump tubes 60, 60' are schematically shown protruding from the sidewall 171 . The peristaltic pump tubes 60, 60' can be respectively connected to the first pump port 62 and the second pump port 62' on the docking station 100.

[0034] It is to be understood that the terms "connect/connected/connection" and/or the like are broadly defined herein to encompass a variety of divergent connected arrangements and assembly techniques. These arrangements and techniques include, but are not limited to (1 ) the direct communication between one component and another component with no intervening components therebetween; and (2) the communication of one component and another component with one or more

components therebetween, provided that the one component being "connected to" the other component is somehow in operative communication with the other component (notwithstanding the presence of one or more additional components therebetween).

[0035] In describing and claiming the examples disclosed herein, the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise.

[0036] It is to be understood that the ranges provided herein include the stated range and any value or sub-range within the stated range. For example, a range from about 250 SCCM to about 1000 SCCM should be interpreted to include not only the explicitly recited limits of about 250 SCCM and about 1000 SCCM, but also to include individual values, such as 250 SCCM, 375 SCCM, 750 SCCM, etc., and sub-ranges, such as from about 270 SCCM to about 500 SCCM, etc. Furthermore, when "about" is utilized to describe a value, this is meant to encompass minor variations (up to +/- 10%) from the stated value.

[0037] Furthermore, reference throughout the specification to "one example", "another example", "an example", and so forth, means that a particular element (e.g., feature, structure, and/or characteristic) described in connection with the example is included in at least one example described herein, and may or may not be present in other examples. In addition, it is to be understood that the described elements for any example may be combined in any suitable manner in the various examples unless the context clearly dictates otherwise.

[0038] While several examples have been described in detail, it will be apparent to those skilled in the art that the disclosed examples may be modified. Therefore, the foregoing description is to be considered non-limiting.