TECHNICAL FIELD

The present disclosure relates generally to tires, and more particularly, to tire sensors and related methods.

BACKGROUND

Currently, tire pressure sensors may be provided in vehicle tires. Such sensors may be used to automatically monitor tire pressure, and a warning (e.g., a warning light) may be provided to the driver when low pressure is detected. Other aspects of the tire, however, may require manual monitoring and failure to adequately monitor such aspects may cause issues relating to safety. Accordingly, improved monitoring of vehicle tires may be desired.

SUMMARY

According to some embodiments of inventive concepts, a method of monitoring tire tread may be provided. Thickness parameter information associated with a tread portion of the tire may be generated, and reference parameter information associated with a reference portion of the tire may be generated. Tread wear information may be generated based on the thickness parameter information and the reference parameter information.

According to some other embodiments of inventive concepts, a tire tread monitoring system may be provided. The tire tread monitoring system may include a measurement sensor, a reference sensor, and a controller coupled with the measurement sensor and the reference sensor. The controller may be configured to generate thickness parameter information associated with a tread portion of the tire based on an electrical response of the measurement sensor, to generate reference parameter information associated with a reference portion of the tire based on an electrical response of the reference sensor, and to generate tread wear information based on the thickness parameter information and the reference parameter information. BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the disclosure and are incorporated in and constitute a part of this application, illustrate certain non-limiting embodiments of inventive concepts. In the drawings:

Figure 1 is a photograph of a cross section of a tire tread including tread blocks and grooves between tread blocks;

Figure 2 is a schematic diagram illustrating first and second sensors using separate grounded electrodes mounted on an inside surface of a tire according to some embodiments of inventive concepts;

Figure 3 is a schematic diagram illustrating first and second sensors using a shared grounded electrode mounted on an inside surface of a tire according to some embodiments of inventive concepts;

Figure 4 is a plot illustrating a measured parameter as a function of tire thickness according to some embodiments of inventive concepts;

Figure 5 is a photograph illustrating a lid and a carrier according to some embodiments of inventive concepts together with a 1 Euro coin provided to illustrate scale;

Figure 6 is a photograph illustrating a rubber mount according to some embodiments of inventive concepts;

Figure 7 is a cross-sectional/side view of a tread wear sensor mounted inside a carrier of Figure 5 according to some embodiments of inventive concepts;

Figure 8 to a top view of a tread wear sensor of Figure 7 according to some embodiments of inventive concepts;

Figure 9 is a cross-sectional/side view of a tread wear sensor mounted in the carrier of Figure 5 with a battery and a printed circuit board according to some embodiments of inventive concepts;

Figure 10 is a block diagram illustrating elements of a tire monitoring system according to some embodiments of inventive concepts; and

Figures 11A and 11B are schematic diagrams illustrating operation of a tread wear sensor according to some embodiments of inventive concepts. DETAILED DESCRIPTION

Inventive concepts will now be described more fully hereinafter with reference to the accompanying drawings, in which examples of embodiments of inventive concepts are shown. Inventive concepts may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of present inventive concepts to those skilled in the art. It should also be noted that these embodiments are not mutually exclusive. Components from one embodiment may be tacitly assumed to be present/used in another embodiment.

The following description presents various embodiments of the disclosed subject matter. These embodiments are presented as teaching examples and are not to be construed as limiting the scope of the disclosed subject matter. For example, certain details of the described embodiments may be modified, omitted, or expanded upon without departing from the scope of the described subject matter.

The measurement of tire tread using electrical signals as described in previous patents, applications and disclosures (e.g., U.S. Patent No. 9,797,703, ET.S. Prov. App. No. 62/515,245, U.S. Prov. App. No. 62/587,660, and U.S. Utility App. No. 15/133,727) may use/require a correlation between the measurement parameter (e.g., Impedance at a fixed frequency) and actual tread thickness. As tire dielectric properties may profoundly affect measurement response, and because properties may vary across different tire designs, within a tire or in a tire over time (due to aging effects of the rubber compound), it may be useful/necessary to provide a reference measurement. The disclosures of each of the following patents/applications are hereby incorporated herein in their entireties by reference: U.S. Patent No. 9,797,703, U.S. Prov. App. No. 62/515,245, U.S. Prov. App. No. 62/587,660, and U.S. Utility App. No. 15/133,727

One way to provide a reference or datum over the lifetime of the tire is to measure in the tire groove where there is no tread and where rubber thickness of the tire does not change with wear (see Figure 1). By referencing the thickness of the tire in the groove, the sensor reading from this area can be subtracted from the measurement in the tread area. Having this reference may provide a benefit of giving the user a clear correlation between thickness and measurement parameter upon installation of a sensor in a new tire. It may also reduce dependence on complex correlations or tire property look-up tables (databases). According to some embodiments of inventive concepts, a pair of sensors (each with a signal and ground electrode) are mounted inside the same tire, roughly adjacent to each other such that one sensor (the reference sensor) is mounted directly below a tire groove. A second sensor, the measurement sensor, is mounted directly below a tire tread block (Figure 2).

According to some other embodiments (Fig 3), a three electrode device may be used instead of a pair of separate sensors. In this case, the center electrode is shared between the two sensors with a common ground. The two separate signal electrodes are placed such that the signal-ground electrode gap is located beneath the tire pattern of greatest interest (e.g. groove or tread block).

Figure 4 is a plot of a measured parameter as a function of tire thickness. The measured parameter, P, is inversely proportional to the thickness (although different parameters may have a different mathematical relation). The measurement parameter may be one of several different electrically measured values including Impedance, Reactance, Frequency, or Sn (which is a measurement based on reflection of a Radio Frequency RF signal). According to some embodiments, at the beginning of the tire life, the two sensors would measure parameters Pref and P0 respectively. As the tire tread thins over time, the tread block sensor will read a higher parameter, Pl while the reference sensor will continue to read Pref. In this way, as the tread block continues to thin towards zero thickness it can be monitored with respect to Pref.

The actual tire tread thickness can be determined using the following relationship:

where i f,ull initial tread thickness

P _tv j= reference parameter measurement

thickness parameter measurement of full thickness tread

P = thickness parameter measurement at time, i

Implementations according to some embodiments may include:

• a single package with two sensors inside designed to align to pre-described tread patterns o A multitude of designs might be manufactured to meet different spectrums of tire tread patterns (e.g., different spacings/widths of tread blocks and/or grooves.

• A single package with multiple sensors inside where the user can select which sensors to use for desired/optimal alignment to tire tread pattern • Two or more packages with unique sensors in each package connected electrically that allow the user to define spacing between sensor packages for desired/optimal alignment to tire tread pattern

• A three electrode design in which the center electrode acts as a common ground with the outer electrodes acting independently and sampling different sections of tire.

Methods of use according to some embodiments may include:

• Applying one sensor on the inside surface of a tire, directly opposite of a tread block.

Applying a second sensor on the inside surface of a tire, directly opposite of a groove. o If the sensors are in a single package (for example a three-electrode device or multiple electrode device, the package should/must be properly aligned to the tread block and groove opposite the respective sensors.

• Providing the system with the starting tread depth to allow calculation of tread depth based on a ratio of measured parameter to the reference parameter.

o In the case of used tires, the starting tread depth should/must be measured at the time of sensor installation.

According to some embodiments of inventive concepts, printed tread wear sensors (TWS) may be used to monitor vehicle tire tread wear. There may be different ways to package such printed tread wear sensors for tire deployment. One approach for Tire Pressure Monitoring Systems TPMS is a package scheme like the one presented by VDO

(http://www.vdo.com/passenger-cars/tire-pressure-monitori ng-systems-tpms/the-vdo-redi- sensor/). In this approach, the TPMS sensors, battery, sense electronics and RF communications are all housed inside a small carrier roughly 1 inch in diameter as shown in Figure 5 including a carrier and a lid. The lid is placed over the contents of the carrier and sealed, and this“package” is then placed inside a rubber mount (shown in Figure 6) that is attached to the inside surface of the tire by an adhesive. The base of the package carrier may thus be mounted adjacent to the inside surface of the tire. According to some embodiments of inventive concepts, a tread wear sensor may be mounted in the same carrier and share the power management and RF (Radio Frequency) communications hardware used for TPMS. According to some embodiments of inventive concepts, methods may be provided to integrate tire tread wear and pressure monitoring systems. Tread wear sensor structures/designs and methods according to some embodiments disclosed herein may enable integration with a tire pressure monitor into a carrier/package.

According to some embodiments, the tread wear sensor may be placed at the base of the carrier (also referred to as the bottom of the carrier) to position the sensor close to the inner tire surface. In some TPMS designs, the battery may be placed at the bottom of the carrier.

According to some embodiments, the tread wear sensor (e.g., the tread wear sensor elements) may be positioned between the battery and a base of the carrier. This design may position the tread wear sensor close to the tire surface (e.g., as close as possible) and may reduce/avoid RF (radio frequency) interference from the battery and/or electronics in the package. According to some embodiments, an epoxy or similar underfill or potting material may be used underneath and/or above the tread wear sensor to secure the tread wear sensor. In addition, this

underfill/potting material may protect the tread wear sensor from harsh operating conditions including varying humidity and/or mechanical shock/vibration. The orientation of the tread wear sensor could be either upward facing or downward facing.

Figure 7 is a cross-sectional/side view of a tread wear sensor (labeled“sensor”) mounted inside the carrier of Figure 5. As shown, the tread wear sensor may be provided adjacent a base of the carrier, and an underfill/potting material may be provided on the tread wear sensor.

Moreover, sensor leads (e.g., pigtail sensor leads) from the sensor may extend through the underfill/potting material to provide electrical coupling with control circuitry. Figure 8 is a top view of the tread wear sensor of Figure 7 in the carrier. For purposes of illustration, the tread wear sensor is shown through the underfill/potting material in Figure 8, but it will be understood that the underfill/potting material may cover the tread wear sensor (except for the pigtail sensor leads). A single sensor (including sensor elements, also referred to as sensor electrodes) is shown in Figure 8 for purposes of illustration, but multiple sensors (e.g., a measurement sensor and a reference sensor) may be provided according to embodiments of Figures 2 and 3. For example, four sensor electrodes (and respective leads) may be provided in Figure 8 to provide the sensors of Figure 2, or three sensor electrodes (and respective leads) may be provided in Figure 8 to provide the sensors of Figure 3 (with a shared grounded electrode).

Figure 9 is a cross-sectional/side view of the tread wear sensor mounted inside the carrier of Figure 5 with a battery and printed circuit board PCB. The pigtail sensor leads (“leads”) of the tread wear sensor may extend out of the carrier and may wrap around the battery and printed circuit board PCB. The leads of the tread wear sensor may then be attached to the PCB by soldering (surface mount technology), conductive epoxy, or by a connector or socket. It may be useful to include additional dielectric shielding (not shown in Figure 9) between the battery and the tread wear sensor. According to some embodiments, the underfill/potting material may provide adequate dielectric shielding, but in other embodiments, different/additional layers may be added.

Additional modifications to the tread wear sensor may further facilitate integration with the tire pressure monitor in the final package. According to some embodiments, the tread wear sensor may be encapsulated by applying a thin Kapton, PET (polyethylene terephthalate), or other layer over the top surface of the tread wear sensor after printing. This encapsulation may extend down the length of the leads but leave exposed the ends of the leads for subsequent electrical connection. Metal vias or feedthroughs may be provided in the tread wear sensor substrate (e.g., Kapton), particularly at the ends of the leads to improve subsequent electrical connection. These metal vias/feedthroughs may allow electrical and mechanical interface to the printed traces from either the top or bottom side of the sensor substrate. This may provide a thick, mechanically robust metal layer for connection either by solder, conductive epoxies or socket connectors, allowing for electrical connection from either side of the substrate. In addition, a metal layer may be provided on the backside of the sensor substrate (away from the carrier base and the tire surface) to provide an effective RF ground plane. This ground plane layer may be continuous or discontinuous based on RF characteristics of the sensor.

According to some embodiments, the sensor elements may be provided on a flexible sensor substrate, and mounted so that the sensor elements are between the flexible sensor substrate and the carrier base, and so that the sensor elements are between the flexible sensor substrate and the inner surface of the tire. Moreover, a metal layer may be provided (e.g., as an RF ground plane) on the backside of the sensor substrate so that the sensor substrate is between the metal layer and the sensor elements. In such embodiments, the sensor elements may be between the backside metal layer and the carrier base, and between the backside metal layer and the inner surface of the tire.

A lid (e.g., as shown in Figure 5) may be provided over the carrier of Figure 9 to seal the tread wear sensor, battery, and PCB within the carrier/lid package, and the carrier base may be mounted on an inside surface of the tire to be monitored. The structure of Figure 9 may thus be used to provide an integrated tread wear sensor and pressure monitor. While one PCB is shown in Figure 9 for purposes of illustration, control circuitry may be provided using one or a plurality of PCBs. Moreover, a pressure sensor (e.g., a micro-electro-mechanical-system MEMS pressure sensor) may be provide (inside the carrier/lid package) with the PCB (e.g., mounted on the PCB) to provide tire pressure monitoring. Components of the integrated tire monitoring system are illustrated in the block diagram of Figure 10.

As shown in Figure 10, circuitry may be provided in/on the printed circuit board to provide controller 601, wireless interface 603 (including a transmitter), and/or pressure sensor 605. Controller 601 and/or wireless interface 603 may be implemented using one or more integrated circuit devices that may be mounted (soldered) on PCB (or otherwise coupled with PCB). Moreover, pressure sensor 605 may be a MEMS pressure sensor that is provided as a discrete device on/in the PCB, and/or pressure sensor 605 may be integrated with circuits used to provide controller 601 and/or wireless interface 603. As shown in Figure 9, battery 609 may be positioned between the PCB and tread wear sensor 607 in the carrier, with the tread wear sensor positioned between battery 609 and the base of the carrier (which is mounted to the inside surface of the tire).

Controller 601 (also referred to as a control circuit or control circuitry) may thus generate tire pressure information based on signals received from pressure sensor 605, and controller 601 may thus generate tread wear information based on signals received from measurement and reference tread wear sensors 607. The tire pressure information and/or tread wear information may thus be transmitted through wireless communication interface 603 (also referred to as a wireless interface circuit or wireless interface circuitry) to a receiver in the vehicle that provides the information to a controller in the vehicle. The wireless interface 603 may thus provide wireless communication (e.g., radio communication) with a receiver in the vehicle to facilitate wireless transmission of tire pressure and/or tread wear information from the spinning tire to the vehicle controller. The wireless interface 603 may also receive information (e.g., instructions) from a transmitter in the vehicle, such as instructions to transmit tire pressure and/or tread wear information. While pressure and tire wear sensors are discussed by way of example, other sensors (e.g., a temperature sensor) may also be included in the tire monitoring system. With a temperature sensor, for example, controller 601 may generate temperature information based on signals received from the temperature sensor, and controller 601 may transmit such temperature information through wireless communication interface 603 to the receiver in the vehicle.

Operations of the tire monitoring system may be performed by controller 601 and/or wireless communication interface 603. For example, controller 601 may control wireless communication interface 603 to transmit communications (e.g., tread wear and/or tire pressure information) through wireless communication interface 603 over a radio interface to a vehicle receiver and/or to receive communications (e.g., requests for information) through wireless communication interface 603 from a vehicle transmitter over a radio interface. Moreover, modules may be stored in memory, and these modules may provide instructions so that when instructions of a module are executed by controller 601, controller 601 performs respective operations (e.g., operations discussed below with respect to the claims).

Figures 11A and 11B are schematic diagrams illustrating operation of a tread wear measurement sensor according to some embodiments of inventive concepts. In the illustration of Figures 11A and 11B, the tread wear measurement sensor is shown on an inside surface of the tire without the other elements of Figures 9/10 to more clearly illustrate operations thereof. Operation of the tread wear measurement sensor is based on the mechanics of how electric fields interact with different materials. As shown in Figures 8 and 11B, the tread wear measurement sensor includes two electrically conductive sensor elements (also referred to as electrodes) side- by-side and very close to each other, and positioning the two sensor elements adjacent to the inside of the tire as shown in Figures 11A and 11B. As shown in Figure 9, the carrier base may be between the sensor elements and the inside surface of the tire, but the carrier has been omitted from Figures 11 A and 11B for each of illustration.

The controller 601 may thus apply an oscillating electrical voltage to one of the sensor elements (the signal electrode) while the other sensor element (the grounded electrode) is grounded to generate an electrical field between the two sensor elements (shown as arcs in Figures 11A and 11B). While most of the electric field may pass directly between edges of the electrodes, some of the electric field arcs from the face of one electrode to the face of the other electrode through the tire tread (shown by arcs in Figures 11A and 11B). The tire rubber and tread structure interfere with this“fringing field,” and by measuring this interference through the electrical response of the grounded sensor element, the controller 601 may thus generate thickness parameter information associated with the tread portion of the tire. A reference sensor placed opposite one of the grooves as shown in Figure 2 or Figure 3 may similarly be used to generate reference parameter information, and the information from the two sensors may be used to more accurately determine the thickness of the tread (as compared with a determination using only one sensor). According to some embodiments, controller 601 may determine the thickness (e.g., using the formula discussed above for t) and transmit the thickness through wireless interface 603 to a vehicle receiver. According to some other embodiments, controller 601 may transmit raw information to the vehicle receiver so that the thickness is actually determined within the vehicle.

In the above-description of various embodiments of present inventive concepts, it is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of present inventive concepts. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which present inventive concepts belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

When an element is referred to as being "connected", "coupled", "responsive", or variants thereof to another element, it can be directly connected, coupled, or responsive to the other element or intervening elements may be present. In contrast, when an element is referred to as being "directly connected", "directly coupled", "directly responsive", or variants thereof to another element, there are no intervening elements present. Like numbers refer to like elements throughout. Furthermore, "coupled", "connected", "responsive", or variants thereof as used herein may include wirelessly coupled, connected, or responsive. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. Well-known functions or constructions may not be described in detail for brevity and/or clarity. The term "and/or" includes any and all combinations of one or more of the associated listed items.

It will be understood that although the terms first, second, third, etc. may be used herein to describe various elements/operations, these elements/operations should not be limited by these terms. These terms are only used to distinguish one element/operation from another element/operation. Thus, a first element/operation in some embodiments could be termed a second element/operation in other embodiments without departing from the teachings of present inventive concepts. The same reference numerals or the same reference designators denote the same or similar elements throughout the specification.

As used herein, the terms "comprise", "comprising", "comprises", "include", "including", "includes", "have", "has", "having", or variants thereof are open-ended, and include one or more stated features, integers, elements, steps, components or functions but does not preclude the presence or addition of one or more other features, integers, elements, steps, components, functions or groups thereof. Furthermore, as used herein, the common abbreviation "e.g.", which derives from the Latin phrase "exempli gratia," may be used to introduce or specify a general example or examples of a previously mentioned item, and is not intended to be limiting of such item. The common abbreviation "i.e.", which derives from the Latin phrase "id est," may be used to specify a particular item from a more general recitation.

The dimensions of elements in the drawings may be exaggerated for the sake of clarity. Further, it will be understood that when an element is referred to as being "on" another element, the element may be directly on the other element, or there may be an intervening element therebetween. Moreover, terms such as "top," "bottom," "upper," "lower," "above," "below," and the like are used herein to describe the relative positions of elements or features as shown in the figures. For example, when an upper part of a drawing is referred to as a "top" and a lower part of a drawing is referred to as a "bottom" for the sake of convenience, in practice, the "top" may also be called a "bottom" and the "bottom" may also be a "top" without departing from the teachings of inventive concepts (e.g., if the structure is rotate 180 degrees relative to the orientation of the figure).

Example embodiments are described herein with reference to block diagrams and/or flowchart illustrations of computer-implemented methods, apparatus (systems and/or devices) and/or computer program products. It is understood that a block of the block diagrams and/or flowchart illustrations, and combinations of blocks in the block diagrams and/or flowchart illustrations, can be implemented by computer program instructions that are performed by one or more computer circuits. These computer program instructions may be provided to a processor circuit of a general purpose computer circuit, special purpose computer circuit, and/or other programmable data processing circuit to produce a machine, such that the instructions, which execute via the processor of the computer and/or other programmable data processing apparatus, transform and control transistors, values stored in memory locations, and other hardware components within such circuitry to implement the functions/acts specified in the block diagrams and/or flowchart block or blocks, and thereby create means (functionality) and/or structure for implementing the functions/acts specified in the block diagrams and/or flowchart block(s).

These computer program instructions may also be stored in a tangible computer-readable medium that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable medium produce an article of manufacture including instructions which implement the functions/acts specified in the block diagrams and/or flowchart block or blocks. Accordingly, embodiments of present inventive concepts may be embodied in hardware and/or in software (including firmware, resident software, micro-code, etc.) that runs on a processor (also referred to as a controller) such as a digital signal processor, which may collectively be referred to as "circuitry," "a module" or variants thereof.

It should also be noted that in some alternate implementations, the functions/acts noted in the blocks may occur out of the order noted in the flowcharts. For example, two blocks shown in succession may in fact be executed substantially concurrently or the blocks may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Moreover, the functionality of a given block of the flowcharts and/or block diagrams may be separated into multiple blocks and/or the functionality of two or more blocks of the flowcharts and/or block diagrams may be at least partially integrated. Finally, other blocks may be added/inserted between the blocks that are illustrated, and/or blocks/operations may be omitted without departing from the scope of inventive concepts. Moreover, although some of the diagrams include arrows on communication paths to show a primary direction of communication, it is to be understood that communication may occur in the opposite direction to the depicted arrows.

Many variations and modifications can be made to the embodiments without substantially departing from the principles of the present inventive concepts. All such variations and modifications are intended to be included herein within the scope of present inventive concepts. Accordingly, the above disclosed subject matter is to be considered illustrative, and not restrictive, and the examples of embodiments are intended to cover all such modifications, enhancements, and other embodiments, which fall within the spirit and scope of present inventive concepts. Thus, to the maximum extent allowed by law, the scope of present inventive concepts are to be determined by the broadest permissible interpretation of the present disclosure including the following claims and their equivalents, and shall not be restricted or limited by the foregoing detailed description.