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TEXT OF THE DESCRIPTION

Field of the invention

The present invention relates to motor-vehicle braking systems, of the type comprising a plurality of disc or drum brakes associated with respective wheels of the motor-vehicle.

Prior art

Devices have already been proposed in the past for signaling the occurrence of wear of the friction material of the motor-vehicle brakes, including electrical devices configured to turn on a relative warning light on the motor-vehicle instrument panel, and mechanical devices comprising a lamella located on the disc brake pad, configured to slide against the brake disc to cause noise while the motor-vehicle is running, in order to signal that the pad has worn out.

The document WO 2016/102793 A1 discloses a device comprising a microphone mounted in the passenger compartment, capable of detecting the noise during braking caused by the wear of the friction material, and turning on a warning light on the motor-vehicle instrument panel.

However, all of the solutions mentioned above are not without drawbacks of sorts.

Signaling devices of the electric type as indicated above involve considerable costs and complexity, considering the components necessary to obtain an electric signal generated by the noise on all the wheels of the motor-vehicle. Mechanical signaling devices, on the other hand, cause annoying noises for the occupants of the motor-vehicle until the worn pads are replaced.

The present invention starts from the desire to overcome all the aforesaid drawbacks.

Object of the invention The object of the present invention is to resolve the above drawbacks with relatively simple and low-cost means.

A further object of the invention is that of producing a method and a system capable of effectively signaling the occurrence of wear of the friction material of the brakes of the motor-vehicle, so as to reduce as much as possible any inconvenience for the occupants, without however affecting the safety.

Summary of the invention

According to one or more embodiments, the above-mentioned objects are achieved through a method and a system having the characteristics specifically set forth in the attached claims.

Brief description of the figures

Further characteristics and advantages of the invention will become apparent from the description that follows with reference to the attached drawings, provided purely by way of non-limiting example, wherein:

- Figure 1 is a diagram of a braking system according to the present invention,

- Figure 2 is a flow diagram that illustrates an embodiment example of the method according to the invention.

In Figure 1 , the references R1 , R2, indicate the two front wheels and the two rear wheels, respectively, of a motor-vehicle, each of which is associated with a brake, indicated by F1 , F2, F3, F4, respectively. In Figure 1 , the respective brakes F1 , F2, F3, F4 are represented as disc brakes of the motor-vehicle. However, the present invention is equally applicable to brakes of the drum type as well. Each of the brakes F1 , F2, F3, F4 can, therefore, be made according to any technique widely known to the expert in the field.

In the case of the illustrated example, the brakes F1 , F2, F3, F4 comprise a disk D rigidly connected to the wheel hub, so as to be able to rotate with the wheel R1 , R2, and a brake caliper C carried by the structure of the motor-vehicle (not shown) and configured to engage the disc D to slow down its rotation. In one or more embodiments, the caliper C includes a caliper body on which a pad configured to engage a face of the disc D is rigidly connected.

According to the invention, the braking system is associated with at least one detection device S configured for detecting the noise generated by the brakes F1 , F2, F3, F4 while the motor-vehicle is running, caused by the wear of the friction material of the brakes F1 , F2, F3, F4. In one or more embodiments, the detection device S is a microphone device installed on board the motor-vehicle, in particular inside the passenger compartment.

According to the invention, the braking system further comprises at least one electronic controller E configured and programmed to check whether the detected noise exceeds a predetermined threshold value.

According to an important characteristic of the invention, the electronic controller E is also configured and programmed to generate an anti-phase noise able to reduce or eliminate the noise generated by the wear of the friction material. In other words, the electronic controller E is essentially configured to generate a noise in real time, which is specular but opposite to that picked up. In one or more embodiments, loudspeakers mounted inside the passenger compartment reproduce the processed signal in the form of sound waves. The result is that two types of sounds reach the ears of the occupants at the same time: the noise generated by the wear of the friction material and the specially created opposite acoustic signal. The final effect is the overlapping of the two sound waves, which produces a total cancellation, or a reduction, of the wear noises of the friction material.

Thanks to these characteristics, the system according to the invention is designed to attenuate or completely eliminate the noise generated by the wear of the friction material of the brakes F1 , F2, F3, F4, which can be annoying, also considering the persistence until replacement of the friction material.

In order not to affect the safety for the occupants of the motorvehicle and to prevent the driver from forgetting or not noticing the actual wear that has occurred, the electronic controller E is also configured and programmed to command the activation of a warning signal on the motorvehicle instrument panel. Thanks to this characteristic, the occupant is promptly warned of the actual wear, without having to be disturbed by the noise coming from the brakes F1 , F2, F3, F4.

The flow diagram of Figure 2 illustrates the method of the invention according to a preferred embodiment. The block 100 shows the generation of noise during braking while the motor-vehicle is running, caused by the wear of the friction material on the front and/or rear brakes. The block 101 shows the noise detection step (frequencies and intensities) by means of the detection device S. As previously indicated, the detection device S may be a microphone installed on board the vehicle inside the passenger compartment. Again with reference to Figure 2, the flow diagram shows in block 102 a step wherein the electronic controller E receives any additional signals i1 , i2, iN from respective additional sensors associated with the brakes F1 , F2, F3, F4 (for example, accelerometers), suitable for verifying the nature of the signal acquired with the detection device S, and confirming that the noise generated could actually be caused by the wear of the worn friction material.

In block 103, the electronic controller E verifies whether the identified noise is typical of the mechanical wear indicator. If this is not the case, there is no intervention (block 104) and possibly the noise during braking is in any case acquired by signaling to further information channels, such as a motor-vehicle service station (block 105).

If the multi-frequency noise emission is typical of a mechanical wear indicator, the electronic controller E verifies whether the generated and identified noise exceeds a predetermined threshold value (block 106). If so, the electronic controller E generates an anti-phase noise to reduce or eliminate the intensity of the noise caused by the wear of the friction material (block 107). The block 108 indicates the step for switching on the warning signal of the occurrence of wear of the friction material. Preferably, the warning signal is implemented with the switching on of a warning light on the instrument panel and with the sending of a message indicating wear of the friction material again on the instrument panel or dashboard touchscreen. Finally, the blocks 109, 110 respectively indicate the step of elimination of the warning by means of a suitable button for a possible acquisition plausibility check, and the step of maintaining the messages and of the warning light until it is switched off in service assistance, which can alternatively be implemented. As is evident from the preceding description, the method and the system according to the invention are capable of performing an automatic function of reducing or eliminating the braking noise while the motorvehicle is running, caused by the wear of the friction material, with simple and low-cost means, without prejudice to the safety of the vehicle occupants. A further advantage of the system according to the invention regards the simplicity of implementation even on motor-vehicles for which it was not originally intended.

Of course, without prejudice to the principle of the invention, the details of construction and the embodiments may vary widely with respect to those described and illustrated purely by way of example, without departing from the scope of the present invention.