Process and device of control and regulation of the pressure of tyres adapting to changes in load applied thereto

Abstract

A process and a device of control and regulation of the pressure of tyres apt to ensure the adaptation of the footprint of a tyre to changes in the load applied thereto. The process includes the following steps: measuring the pressure of the tyre, measuring the footprint or the deflection of the tyre, determining a calculated value of footprint or of deflection in function of said optimum value of pressure, said calculated value of footprint or of deflection being determined by means of a correlation, based on experimental data, of values of pressure, footprint or deflection and applied load,
if said calculated value of footprint or of deflection is different from respectively said measured value of footprint or of deflection: modifying the pressure of the tyre to reduce the difference between said measured value of pressure and said optimum value of pressure.

Claims

1. A process of control and regulation of the pressure of tyres, in particular for agricultural use, apt to ensure the adaptation of the footprint of a tyre to changes in the load applied thereto, wherein the process comprises the following steps: measuring the pressure of the tyre, measuring the footprint or the deflection of the tyre, determining a calculated value of the load applied to said tyre, said calculated value of the applied load being determined, in function of said measured value of the footprint or of the deflection and of said measured value of the pressure, by means of a correlation, based on experimental data, of values of pressure, footprint or deflection and applied load, determining an optimum value of pressure corresponding to said calculated value of the applied load, said optimum value of pressure being determined by means of characteristic tables of said tyre, determining a calculated value of footprint or of deflection in function of said optimum value of pressure, said calculated value of footprint or of deflection being determined by means of a correlation, based on experimental data, of values of pressure, footprint or deflection and applied load, if said calculated value of footprint or of deflection is different from respectively said measured value of footprint or of deflection: modifying the pressure of the tyre to reduce the difference between said measured value of pressure and said optimum value of pressure, repeating the steps of the process until said measured value of the footprint or of the deflection reaches said calculated value of the footprint or of the deflection.

2. The process of control and regulation of the pressure of tyres according to claim 1, wherein the process additionally comprises a step of measuring the temperature, the measured values of temperature contributing to the determination of the correlation between values of footprint or of deflection, pressure and load.

3. A device (10) of control and regulation of the pressure of tyres (22), in particular for agricultural use, apt to ensure the adaptation of the footprint of a tyre to changes in the load applied thereto, comprising a pressure meter (11) and a footprint meter or a deflection meter (12) of a tyre (22), an electronic management system (14), connected in input to said pressure meter (11) and to said footprint meter (12) or deflection meter, a compressor (15), actuated by said electronic management system (14), a release and safety valve (17), actuated by said electronic management system (14), and a power supply system (16), wherein said electronic management system (14) being configured to: determining continuously a value of the applied load on said tyre (22), in function of said measured value of the footprint or of the deflection and of said measured value of the pressure, by means of a correlation, based on experimental data, of values of pressure, footprint or deflection and applied load, determining an optimum value of pressure corresponding to said calculated value of the applied load, said optimum value of pressure being determined by means of characteristic tables of said tyre, determining a calculated value of footprint or of deflection in function of said optimum value of pressure, said calculated value of footprint or of deflection being determined by means of a correlation, based on experimental data, of values of pressure, footprint or deflection and applied load, and if said calculated value of footprint or deflection is different from respectively said measured value of footprint or deflection: modifying the pressure of the tyre to reduce the difference between said measured value of pressure and said optimum value of pressure, repeating the steps of the process until when said measured value of the footprint or of the deflection reaches said calculated value of the footprint or of the deflection.

4. The device (10) of control and regulation of the pressure of tyres (22) according to claim 3, wherein said footprint meter comprises: accelerometers, or polymeric material having electrical resistance variable according to deformation.

5. The device (10) of control and regulation of the pressure of tyres (22) according to claim 3, wherein said deflection meter comprises: an extensometer, or a laser system, or an infrared system.

6. The device (10) of control and regulation of the pressure of tyres (22) according to claim 3, wherein the device wherein additionally comprises a temperature meter (13).

7. The device (10) of control and regulation of the pressure of tyres (22) according to claim 3, wherein said power supply system (14) consists in a battery integral with the hub of the wheel of a vehicle on which said tyre is installed.

8. The device (10) of control and regulation of the pressure of tyres (22) according to claim 3, wherein said power supply system (14) is apt to get energy directly from the vehicle on which said tyre is installed.

9. The device (10) of control and regulation of the pressure of tyres (22) according to claim 8, wherein said power supply system (14) is provided with a pair of collectors (18), one for the negative pole and one for the positive pole, connected by means of sliding contact with as many brushes (19) as are required to ensure operation of the whole device (10), in turn electrically connected to the vehicle engine.

10. The device (10) of control and regulation of the pressure of tyres (22) according to claim 8, wherein said power supply system is provided with a three-phase motor, comprising a stator and a rotor, in turn electrically connected to the vehicle.

11. The device (10) of control and regulation of the pressure of tyres (22) according to claim 3, wherein the device is applied to agricultural machines used with heavy loads varying in time, such as harvesters, sprayers, spreaders and trailers.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The present invention will be now described, for illustrative but not limitative purposes, according to its preferred embodiment, with particular reference to the annexed figures, in which:

(2) FIG. 1 shows a radial sectional view of a wheel incorporating a process of control and regulation of the pressure of tyres according to the present invention;

(3) FIG. 2 shows the cycle of control and regulation of the pressure in function of an increase of the load;

(4) FIG. 3 shows the cycle of control and regulation of the pressure in function of a decrease of the load;

(5) FIG. 4 shows the rim of a tyre according to an embodiment of the present invention, and a corresponding collector; and

(6) FIG. 5 shows a representative diagram of the typical loading and unloading cycle of a harvesters.

DESCRIPTION OF SPECIFIC EMBODIMENTS OF THE INVENTION

(7) Referring to the figures, a device of control and regulation of the pressure of tyres according to a preferred embodiment of the present invention is indicated by the reference number 10 and is shown applied on a wheel 20, essentially consisting of a rim 21 and a tyre 22, inside which it is defined an air chamber 23.

(8) The device of control and regulation of the pressure of tyres according to the present invention comprises a pressure meter 11, a deflection meter 12 of the tyre 22 (or alternatively a footprint meter), a temperature meter 13, an electronic management system 14, a compressor 15 and a power supply system 16. In addition, the device of control and regulation of the pressure of tyres according to the present invention includes a release and safety valve 17.

(9) The power supply system 16 can be constituted by a battery integral with the hub of the wheel, or, as shown by way of example but not of limitation with reference to FIG. 4, can extract energy directly from the vehicle on which said tyre is installed, for example through a pair of collectors 18, one for the negative pole and one for the positive pole, connected by means of sliding contact with as many brushes 19 as are required to ensure operation of the whole device, in turn electrically connected to the vehicle engine.

(10) Given the architecture of the device of control and regulation of the pressure of tyres according to the present invention, the same is particularly suited to harvesters (and harvesters/sprayers), considering both the frequent and high variability of the load during the working cycles, and its possible allocation within the rim.

(11) The operation of the process and device of control and regulation of the pressure of tyres according to the present invention is described in the following, with reference to FIGS. 2 and 3, which show two diagrams in which the abscissa axis shows the deflection of the tyre and the ordinate axis shows the load condition. The two curves p1 and p2 show the relationship between the deflection and the load condition, respectively, for two constant pressure values p1 and p2. The operation of the process and the device of control and regulation of the pressure of tyres according to the present invention is explained in detail by referring to the measurement of the deflection, but perfectly similar reasoning can be made in the case in which the measured parameter is the footprint of the tyre.

(12) In particular, referring to FIG. 2, starting from an initial load condition L1, the pressure and the deflection are respectively p1 and d1. By increasing the load up to L2, the two variables increase, respectively up to p1 and d1. The regulation device consequently actuates a compressor, capable of increasing the pressure up to p2 in order to obtain the suitable value of deflection. The p to be imposed is known from the experimental tests carried out on the covering, which relate L, p and d.

(13) The process is similar in the case of reduction of the load, with a reduction of the pressure rather than an increase, as shown with reference to FIG. 3.

(14) By way of example, FIG. 5 represent a loading and unloading cycle typical of a harvesters.

(15) The present invention has been described for illustrative but not limitative purposes, according to its preferred embodiments, but it is to be understood that variations and/or modifications may be made by those skilled in the art without departing from the relative scope of protection, as defined by the appended claims.