FIELD OF THE INVENTION

The present invention relates to the field of automotive and in particular a TPMS system for detecting, storing and reading characteristic operating parameters, such as temperature and pressure, using a RFID technology.

Known art

In the automotive field and especially for commercial vehicles, it is important that tyres are efficient and subjected to suitable maintenance.

Commercial vehicles covers, in fact, at least two hundred thousand Km yearly this implies at least 900 Km/day therefore, if not correctly used, they risk early wear and damaging of the carcass. It becomes therefore essential to use tyres always at a predetermined pressure and a predetermined temperature in order to avoid structural failure. This would cause, in fact, safety problems as well as high costs for the company as well as the risk for the carcass to become unusable for a possible retreading.

The Applicant, in fact, noted that in order to face high costs per covered Km, many companies are investing in the "retreading" factor such to allow a recycle of the carcasses which otherwise would be no longer in use, with high disposal costs and high environmental impact.

Retreaded tyres use as starting material the worn tyres which are firstly "smoothed" and afterwards, through a vulcanization process, the new tread is applied. Tyre carcass is reused for maximum three times, and a proper use is essential so that the retreading process can be actuated for the whole useful life of the carcass, in other terms the tyre should always operate in suitable pressure and temperature conditions, and a constant maintenance of the tyre.

The Applicant noted that in case of accident due to tyre malfunctioning there is great difficulty to place the liability between the tyre manufacturer and tyres users, since there is no documentary proof demonstrating the correct use and maintenance of the tyre with time.

Thus the Applicant has experienced the need of providing a reliable and relatively simple TPMS system for detecting, storing and reading operating parameters in a tyre, such as temperature and pressure.

Generally, with TPMS (tire pressure monitoring system) term an electronic system is meant, that is designed to monitor the inner pressure of tyres on various types of vehicles. Usually, the TPMS systems notify in real time the information related to tyre pressure to the vehicle driver. The TPMS systems can be torn in two different types depending on the way for detecting the inner pressure of a tyre directly also named (dTPMS) or indirectly (iTMPS).

Further the Applicant experienced the need of providing a TPMS system for detecting, storing and reading operating parameters, such as temperature and pressure, which allows to constantly effortlessly and readily monitor the correct operation and maintenance condition of the tyre.

The Applicant eventually experienced the need of providing a TPMS system for detecting, storing and reading operating parameters, such as temperature and pressure, which allows to have the maintenance traceability and the constant monitoring of the tyre.

SUMMARY OF THE INVENTION

Therefore, the invention in a first aspect thereof relates to a TPMS system for detecting, storing and reading operating parameters, such as temperature and pressure, in a tyre comprising:

- at least one device for detecting and storing the operating parameters of a tyre

- at least one protection casing adapted to receive at least partially the device for detecting and storing the operating parameters of a tyre; and

- fastening means for fastening to a tyre rim

characterized in that

said fastening means comprise a fastening member for coupling said at least one protection casing to said rim removably and adjustably depending on the size of the rim; said device for detecting and storing the operating parameters of a tyre comprises:

- at least one antenna for receiving and transmitting signals in radio-frequency; - at least one RFID transponder comprising:

- at least one temperature sensor;

- at least one pressure sensor;

- means for storing data related to temperature and pressure of the tyre which the device for detecting and storing the operation parameters of a tyre is associated to.

The present invention, in the afore said aspect, may present at least one of the preferred characteristics herein after described.

Preferably, the casing comprises at least one containment body and at least two support portions for support on the tyre rim adapted to space by a predetermined height H the said containment body, and particularly a base surface thereof, from a radially outer surface of the rim.

Advantageously, said height H is greater than 0.5 cm.

Preferably, the containment body has a substantially elongate shape arranged according to an arc of a circle.

Conveniently, the containment body comprises an openable lid.

Advantageously, the fastening member comprises a hose clamp adapted to be circumferentially wound about the tyre rim and at least one hinge element for adjusting the winding length of the hose clamp on the tyre and locking the same at a predetermined length so that the hose clamp adheres to the outer surface of the tyre rim.

Preferably, the hinge elements comprise at least one endless thread screw.

Advantageously, the system comprises a radio-frequency reading member for communicating with the said device for detecting and storing the operating parameters of a tyre.

Preferably, the device for detecting and storing the operating parameters of a tyre comprises at least one driving battery.

Advantageously, the RFID transponder further comprises at least one PCB electronic board.

Conveniently, the RFID transponder comprises at least one RFID integrated circuit comprising a UID unique identification code.

Preferably, the RFID transponder comprises a programmable timer for defining the sampling intervals.

According to another aspect the present invention relates to a method for detecting, storing and reading operating parameters, such as temperature and pressure, in a tyre associated to a TPMS system as above described, the method comprising the steps:

- standby wherein the device is in wait of an event;

- activation upon request.

Preferably, the activation step is generated by a request from a RFID reading member outer of the device.

Alternatively, the activation step is generated by an inner request from the PCB electronic card as a function of a predetermined time interval set in the inner timer.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will be more evident from the detailed description of some preferred embodiments, but not exclusive, of a TPMS system for detecting, storing and reading operating parameters, such as temperature and pressure, in a tyre according to the present invention.

Such a description will be hereinafter explained referring to the attached drawings, provided for purposes of illustrations only, and thereby not limitative, wherein:

- figure 1 is a schematic sectional view, in axial direction, of a tyre rim provided with the system for detecting, storing and reading operating parameters, such as temperature and pressure, according to the present invention;

- figure 2 is a schematic sectional view, in circumferential direction, of a tyre rim provided with the system for detecting, storing and reading operating parameters, such as temperature and pressure, according to the present invention;

- figure 3 is a schematic exploded view for detecting, storing and reading the operating parameters, such as temperature and pressure, according to the present invention;

- figure 4 is a schematic enlarged view, of a fastening means;

- figure 5 shows a block diagram of the device for detecting and storing operating parameters, such as temperature and pressure, of a tyre, according to the present invention; and

- in figure 6 a diagram of the operation stages of the device 1 for detecting and storing the operating parameters, such as temperature and pressure, of a tyre, according to the present invention, is shown.

DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE INVENTION

Referring to figures 1-6, a system for detecting, storing and reading operating parameters, such as temperature and pressure, according to the present invention, is identified with reference numeral 100.

The system 100, in the embodiment shown in figure 1 , has at least one device 1 for detecting and storing operating parameters characteristic of a tyre, at least one protection casing 2 adapted to receive the device 1 for detecting and storing the operating parameters of a tyre and fastening means 3 of the device 1 to a rim 14 of a tyre.

The fastening means 3 comprise a fastening member 4 for coupling the protection casing 2 to the rim 14 removably and adjustably depending on the size of the rim.

The reason for fastening to the rim of the device 1 is given by safety requirements since the rim 14 is a safe place from both dynamical strengths and mechanical stresses.

The fastening means 3 will be explained in more detail in the following.

The device 1 for detecting and storing the operating parameters of a tyre, as better shown in figure 3, comprises:

- at least one antenna 5 for receiving and transmitting signals in radio-frequency;

- at least one RFID transponder 6 comprising:

- at least one temperature sensor 7;

- at least one pressure sensor 8;

- at least one PCB electronic card 22 and

- at least one RFID integrated circuit 17. According to an important aspect of the present invention the PCB electronic card comprises means for storing data related to temperature and pressure of the tyre which the device 1 for detecting and storing the operation parameters of a tyre is associated to.

In the embodiment shown in figures, by way of example, there is a memory as means for storing data related to the temperature and pressure of the tyre, preferably a flash type memory.

Preferably, the RFID transponder 6 further comprises a programmable timer for defining the sampling intervals.

The device 1 is completely contained in an apposite protection casing 2.

The protection casing 2 has an elongate containment body 9 comprising a base portion 10 and a removable lid 10' with respect to the base portion 10.

For a better adaptability to the outer surface of the rim, the containment body 9 has a substantially elongated shape arranged according to an arc of a circle.

From the base portion 10 two support portions 11 extend for support on the tyre rim 14 adapted to space by a predetermined height H the containment body 9 and in particular a radially inner surface 13 of the base portion 9 from the radially outer surface 15 of the rim 14.

The height H is greater than 0.5 cm, preferably greater than 0.6 cm.

Advantageously, the height H is lower than 2 cm, preferably lower than 1.5 cm.

The selection of the height H is such to bring the antenna 5 for receiving and transmitting signals in radio frequency to a distance of about 1 cm from the ground plane represented by the rim 14, substantially from the surface 15.

The supporting portions 11 comprise each one a slot, not directly visible in the figures, for associating the fastening member 4 to the protection casing 2.

In detail, in the embodiment shown in figure 4, the fastening means 3 comprise a fastening member 4, represented by a hose clamp 16 adapted to be circumferentially wound about the tyre rim 14 and at least one hinge element 27 for adjusting the winding length of the hose clamp 16 on the tyre and locking the same at a predetermined length so that the hose clamp adheres to the outer surface 15 of the tyre rim 14. Preferably, the hinge element 27 comprises at least one endless thread screw. The selection of such a fastening means has been done so that the size thereof can be changed in order to adapt it to different rim sizes, making the system substantially "universal".

Alternatively, a special glue can be used on the rim 14 as fastening means, but vibrations, dynamical strengths and, sometimes, rust of the rim make it less effective.

According to another embodiment, as fastening means 3 a screw fastening system has been tried.

Alternatively, an elastic rubber element, such an elastic braid, can be used as fastening means 4.

The fastening means 3, as previously mentioned above, are such to reversibly, thus removably, associate the device 1 for detecting and storing the operating parameters of a tyre to the radially outer surface 15 of a rim.

In the embodiment shown in figure 3, the device 1 for detecting and storing the operating parameters of a tyre comprises: a (PCB) electronic card 22, a RFID integrated circuit 17 for identifying and managing the RFID transponder, a driving battery 18, a temperature sensor 7 and a pressure sensor 8.

The RFID integrated circuit 17 is an integrated chip able to manage the RFID communication and it is compatible with the class 1 and 2 epc standards and has a 3 m maximum reading distance. The RFID integrated circuit 17 comprises a UID unique identification code which allows to uniquely identify the rim and the tyre the device 1 for detecting and storing the operating parameters of a tyre is associated to.

The RFID integrated circuit 17 is arranged centrally on the PCB electronic card 22 and comprises an integrated temperature sensor 7.

The temperature sensor 7 is preferably able to detect temperature values comprised between -20°C and 125°C.

The device 1 for detecting and storing the operating parameters of a tyre further comprises an electronic card.

The PCB electronic card 22 comprises a system named "LOG-IN" able to store the acquired data in programmable time intervals (0-9 h) and has the function of managing the pressure sensor 8.

Preferably, the PCB electronic card 22 has a length extent L comprised between 15 cm and 20 cm.

The pressure sensor 8 is a pressure sensor of the type generally known to a skilled technician preferably able to detect pressure values comprised in the range between 1 and 14 bar.

In the embodiment shown in figure 3 the battery 18 is a 3V battery.

In figure 5 a schematic block structure of the device 1 for detecting and storing the operating parameters of a tyre is shown.

The device 1 according to the scheme shown in figure 5 comprises a driving battery 18, an electrical power managing unit 25, a pressure sensor 8, a digital controlling unit 24, an analog section 23 and a temperature sensor 7 and a RF interface with the relative antenna 5.

The unit 25 for managing electrical power is connected to the driving battery 18 which, as previously above mentioned, is a 3V lithium battery. The unit 25 for managing electrical power generates two separated current lines: the first current line for the digital controlling unit 24 and the second current line for the analog section 23.

The pressure sensor 8 is a piezoelectric sensor, able to detect, as previously above mentioned, pressure values comprised in the interval between 1 and 14 bars in a temperature range from -40°C to 125°C.

The sensor 7 of inner temperature, of known type, samples the inner temperature of the tyre substantially contemporaneously with the pressure sampling and it is integrated in the digital controlling unit 24.

The analog section 23 comprises an amplifier and an AID converter (analog to digital).

The amplifier reads and amplifies the voltage differential generated by the pressure sensor 8 at different pressure levels inside the tyre. The differential of voltage coming from the amplifier is fed to the A/D converter for transforming in digital format.

The digital controlling unit 24 contains all logics to implement the activities of the device 1 and the data storing means preferably concerning pressure and temperature inside the tyre.

The RF section checks the wireless communication between the device and the outer RFID reader 20.

The RF section with its antenna 5, more extensively described in the following, can operate as a passive type transponder for reducing energy consumptions.

The system 100 for detecting, storing and reading operating parameters comprises, as above mentioned, a RFID reading member 20 for communicating with the said device 1. Such RFID reading members 20 are readers for transponder of known type usually available in the market and they can be portable/ mobile or at fixed position named "gates". By way of example, such readers can be represented by PSION WORKABOUT 3 or MOTOROLA MC3190-Z readers.

To allow the communication with the RFID reading member 20, the device 1 for detecting and storing operating parameters of a tyre comprises, as previously above mentioned, an antenna 5 and in particular an UHF antenna with transmission frequency comprised in the range between 850 MHz and 1000 MHz.

The antenna 5 extends at least for the whole extent length L of the PCB electronic card 22, preferably the antenna has a length greater than 15 cm.

The studied antenna 5 has the aim to maximize the power received from the device 1 for detecting and storing the operating parameters of a tyre in the particular conditions in which it is intended to operate. The device 1 for detecting and storing operating parameters is in fact assembled on the rim inside a housing and the antenna 5 is therefore operating at a distance of about 1 cm from the ground plane represented by the rim.

Further the tyre acts, by means of the metallic wire present in its inside, as an imperfect "Faraday cage" which causes a partial shielding from external electromagnetic fields.

The used antenna type is the "over ground dipole" whose impedance is studied for obtaining the "matching" condition with the RFID integrated circuit 17 at the use frequency.

The matching of the imaginary part of the impedance is determined by the total length of the dipole (since an inductive behavior has to be obtained the dipole will have a length greater than lambda/2). The matching of the real part of the impedance is determined by the distance of the antenna from the rim. ^

The implementation of the above said matching conditions ensures the maximum sensitivity of the transponder to the use frequency. The matching condition has been obtained by considering all the characteristics of such a type of application and in particular:

a) the positioning of the transponders in a housing;

b) the partial shielding made by the tyre which realizes a housing condition, although imperfect;

c) the fact that the dipole is curved in shape;

d) the presence of the battery which is placed between the antenna and the ground plane making a point reduction of the distance between the antenna and the ground plane itself.

The operation of the system 100 for detecting, storing and reading operating parameters, such as temperature and pressure, in a tyre comprising may provide the following steps:

- identification;

- initialization;

- registration;

- data download.

The identification step provides:

- at least one sub-step, by a reading member 20, of searching one or more RFID transponders 6 present in the generated reading field;

- at least one sub-step of uniquely identifying each individual RFID transponder

6 and reading their UID unique code;

- at least one sub-step of selecting a specific RFID transponder 6 and sending commands.

The initialization step provides on the other hand:

- at least one sub-step of defining the data recording mode (activation limits, measuring frequency, data storage mode etc.)

- at least one sub-step of starting the recording at the desired time. On the contrary in the recording step the RFID transponder 6 selected autonomously, at the planned expiration, carries out the measurements of the instant values of pressure and temperature and records the same into the memory.

Finally in the data download step, after the identifying and selecting step of a single RFID transponder 6, the data download command is issued for the data which are transmitted to the reading member 20.

In figure 6 a diagram of the operation stages of the device 1 for detecting and storing the operating parameters, such as temperature and pressure, of a tyre is shown.

In order to reduce the consumptions of the driving battery 18, the device 1 is usually in a standby mode.

The standby mode can be stopped upon a request coming from the RFID reading member 20 or a request from the PCB electronic card 22 itself depending on a predetermined time interval set in the inner timer.

The request from the PCB electronic card 22 implies a reading and storing in memory step of the detected temperature and pressure data.

The request generated by the RFID reading member 20 can generate the reading of the previously stored data or the reading request for the current values, that is to say for the values detected at the request time.

The present invention has been described referring to some embodiments. To the embodiments herein represented in detail may be made various modifications, anyway remaining in the protection scope of the invention, defined by the following claims.