METHOD AND SYSTEM FOR CAPTURING BRAKING PARTICLES

Abstract

Method for implementing a system (20) for capturing braking particles from a disc brake, the capture system (20) comprising particle suction means (22, 24, 26) and a control unit (30) configured to control the active or inactive state of the suction means (22, 24, 26), the method comprising a succession of cycles, each of the cycles comprising a first step of a first duration during which the suction means (22, 24, 26) are controlled by the control unit (30) to be in an active state and a second step of a second duration during which the suction means (22, 24, 26) are controlled by the control unit to be in an inactive state. Abstract figure: Figure 1

Description

Title of the invention: METHOD AND SYSTEM FOR CAPTURING BRAKING PARTICLES Technical field

[0001] The present disclosure relates to the field of vehicle braking devices (automobiles or railways) or industrial braking devices. The context relates in particular to the aspects of environmental protection by the suction of braking particles emitted by friction brakes, in particular disc brake type brakes. Prior art

[0002] Document FR 3 057 040 A1 describes a disc brake lining equipped with a collection groove and a through orifice, fluidically connected to suction means. This lining makes it possible to efficiently suck up brake dust over the entire radial height of the lining. The suction means comprise a turbine generating a vacuum which sucks up the dust to direct it towards a collection filter.

[0003] Documents DE 198 46 887 A1 and DE 196 43 869 A1 illustrate two examples of control of suction means in which the maximum suction is controlled during braking.

[0004] Document FR 3 088 395 A1 introduces the concept of compensation of the suction according to the filling level of the collection filter: in order to guarantee satisfactory suction throughout the life of the filter, the suction power can increase, if necessary.

[0005] Thus, existing systems systematically recommend activating the suction during braking phases and deactivating the suction after the braking phases. It has been observed that there is a peak in particle formation very quickly after the start of braking. To absorb the majority of the particles, the suction means must therefore react quickly to the triggering of braking: a powerful motor is necessary so that the acceleration of the suction turbine is sufficient, in order to increase speed in the shortest possible time to capture a maximum of particles formed during this peak. Motors powerful enough to obtain appropriate acceleration curves are expensive and create a significant electrical current draw at the time of turbine acceleration.

[0006] A solution presented in document FR 3 088 393 A1 aims to anticipate the start-up of the suction turbine by detecting the activation of a regenerative brake. This solution, however, has the disadvantage of over-activation of the collection system. particles. In fact, the friction brake is not systematically activated when regenerative braking is used. Furthermore, this solution is only possible for vehicles equipped with regenerative braking. Summary

[0007] The present disclosure thus proposes a method for implementing a particle capture system which allows effective suction of braking particles without using a powerful and expensive motor, the rotation of which would create significant peaks in electrical consumption.

[0008] A method is thus proposed for implementing a system for capturing braking particles from a disc brake, the capture system comprising particle suction means and a control unit configured to control the active or inactive state of the suction means, the method comprising a succession of cycles, each of the cycles comprising a first step of a first duration during which the suction means are controlled by the control unit to be in an active state and a second step of a second duration during which the suction means are controlled by the control unit to be in an inactive state.

[0009] The inventors have demonstrated that, surprisingly, activating and deactivating the suction regularly, independently of the activation of the brake, makes it possible to capture a significant and sufficient level of particles. Without wishing to be bound by theory, these good results seem to come from two factors. The first factor seems to be the fact that the suction zone of the pad (for example a groove at the trailing edge of the pad or a peripheral groove) can serve as a reservoir of particles during the braking phases, even in the absence of suction. The second factor is the fact that during suction, the particles stored in the asperities of the disc are sucked up, whether it is suction during the activation of the brake or in the absence of braking.By activating the suction cyclically, i.e. uncorrelated with the brake activation, the need to quickly activate the suction at the time of braking to absorb the particles at the time of the peak discussed above is eliminated. Consequently, there is no longer any need to provide the system with a powerful motor causing peaks in electrical consumption.

[0010] Cyclic activation and deactivation is to be understood in the sense of an alternation, or a continuous and direct succession of switches between the active state and the inactive state.

[0011] The “active” state corresponds to the generation of a depression and therefore of a suction air flow, whereas the “inactive” state corresponds to an absence of suction.

[0012] The “suction means” comprise one or more elements configured to create a low pressure flow in the vicinity of the interface between the disc and the lining. friction. The documents cited above give examples of structures for generating this low-pressure flow. Examples include: a caliper cover, a suction nozzle, a lining with a groove and a through-hole. The source of low-pressure may consist of a turbine driven by a motor. The "active" state corresponds to a rotating motor and the "inactive" state corresponds to a stationary motor. The method described here therefore alternates between driving and stopping the motor and no longer requires the system to be equipped with a powerful motor that must ensure rapid rotation upon detection of the start of a braking phase. Thus, a smaller, less expensive, lighter motor that consumes less electrical power can be used in the system.

[0013] By “control unit” is meant a hardware and / or software element dedicated to the control of the capture system or integrated into one of the main controllers of the vehicle (CAN, ECU, EMS, etc.) or of the industrial machine.

[0014] Furthermore, it is implicit that the first and second durations are non-zero, otherwise the suction would be continuous or totally inactive.

[0015] The intended application includes disc brakes for motor vehicles or railways or industrial disc brakes. In this type of brake, one or more linings come into contact with one or more discs. It is understood that the particle capture system of the present disclosure is also capable of capturing particles from other types of brake, particularly drum brakes.

[0016] According to another aspect, the first duration is between 5 seconds and 2 minutes, preferably between 10 seconds and 1 minute.

[0017] According to another aspect, the second duration is between 30 seconds and 30 minutes, preferably between 4 and 10 minutes.

[0018] According to another aspect, the ratio between the first duration and the second duration is between 1 / 3 and 1 / 10.

[0019] According to another aspect, the control unit receives a signal indicative of the rotational speed of the disc and the suction means are commanded to remain inactive if the rotational speed of the disc is below a threshold. This is particularly advantageous for a brake fitted to a vehicle: suction can be risky at low speed when the vehicle is fording, since water can penetrate the suction circuit. Beyond a certain speed, the risk no longer exists. Tests have shown that driving in the rain does not present this risk of water being sucked into the pneumatic circuit. The threshold speed may depend on the vehicle in question and may be of the order of 2 to 3 revolutions per second (25 to 30 km / h).

[0020] According to another aspect, a degree of wear of the disc is monitored, and the first and second durations are adjusted such that the ratio between the first duration and the second duration increases with wear of the disc.

[0021] According to another aspect, the brake comprises a pair of linings; a disc having two annular friction surfaces, respective locations of friction of the linings on the disc, each of the annular friction surfaces being delimited by an internal circle and an external circle; and the particle capture system comprises two grooves fluidically connected to the source of depression and arranged at a distance from the friction linings, each of the grooves being arranged opposite a respective annular friction surface, each groove extending from the internal circle to the external circle.

[0022] The invention also relates to a system for capturing braking particles emitted by a disc brake, the capture system comprising: particle suction means capable of assuming an active or inactive state; and a control unit configured to switch the suction means alternately between an active state and an inactive state in accordance with the method described above.

[0023] The invention also relates to a disc brake comprising a particle capture system as described above and in which the active or inactive state of the suction means is regulated independently of the activation of the brake.

[0024] According to another aspect, the brake comprises a pair of brake pads, each having a particle collection groove, the suction means of the particle capture system being fluidically connected to the particle collection grooves.

[0025] According to another aspect, the brake comprises a pair of friction linings; a disc having two annular friction surfaces, respective locations of friction of the linings on the disc, each of the annular friction surfaces being delimited by an inner circle and an outer circle; and a braking particle capture system comprising: a vacuum source; and two suction grooves fluidly connected to the vacuum source and arranged at a distance from the friction linings, each of the grooves being arranged opposite a respective annular friction surface, each groove extending from the inner circle to the outer circle.

[0026] By "each groove extending from the inner circle to the outer circle" it is understood that the groove overhangs, when the disc rotates, the entirety of one of the friction surfaces. The groove may be slightly larger or slightly smaller (for example + / - 10%) than the distance between the inner circle and the outer circle.

[0027] According to another aspect, each groove is substantially rectilinear and has a width measured in a circumferential direction which is between 1 and 6 mm, and which is preferably 2 or 4 mm.

[0028] The groove may be configured to create a suction flow that is perpendicular to the annular friction surfaces. In one embodiment, the flow is parallel to the radial direction.

[0029] According to another aspect, each groove is arranged in a respective nozzle. There are thus two nozzles facing each other on either side of the disc.

[0030] According to another aspect, each nozzle has at least one leak orifice in fluid connection with the groove. Such an orifice makes it possible to initiate an air flow in the opposite direction to the direction of movement of the disc. In one variant, the nozzle comprises two orifices on two opposite faces (upstream and downstream) of the nozzle. In another variant, two leak orifices may be provided on a rear face of the nozzle, the suction then being able to be made by a suction orifice centered relative to the two leak orifices, in order to minimize the path taken by the air in the grooves and promote the efficiency of the suction.

[0031] According to another aspect, each nozzle is arranged at an axial distance of less than three millimeters, preferably less than 0.1 mm, from the respective annular friction surface.

[0032] According to another aspect, each nozzle comprises a downstream edge provided with a seal or a brush in contact with the respective annular friction surface. Thus, an upstream edge of the nozzle, that is to say the first edge that a point of the disk “sees” during its rotation, can be at a distance from the disk while the downstream edge, provided with the seal, is in contact with the disk. This seal makes it possible to scrape any particles to further improve their suction.

[0033] According to another aspect, each nozzle comprises an upstream edge and a downstream edge, the downstream edge being further from the respective annular friction surface than the upstream edge. This makes it possible to draw air downstream of the nozzle and to initiate a flow in the opposite direction to the movement of the disc.

[0034] According to another aspect, the groove of each nozzle has a longitudinal direction which is arranged in alignment with a radius of the disc, said radius being preferably angularly offset from a median radius of the linings, by an angle of between 20° and 60°. This angle materializes the clearance between the pads and the nozzles. An angle that is too small poses constraints in the design of the nozzles due to the proximity of the caliper. An angle that is too large complicates the attachment of the nozzles which can no longer be attached to the caliper.

[0035] According to another aspect, the brake comprises a fixed caliper or a floating caliper sliding relative to a yoke, the nozzles being fixed to the fixed caliper or to the yoke. This makes it possible in particular to avoid a complex system of fixing the nozzles to the vehicle.

[0036] According to another aspect, the particle capture system comprises two rigid conduits each connected to a respective nozzle and by means of which the nozzles are held in position opposite the disc.

[0037] According to another aspect, a fixing lug connects the rigid pipes to the stirrup or to the yoke, the fixing lug comprising two orifices crossed by the rigid pipes.

[0038] According to another aspect, the two grooves are arranged in a single nozzle. This single nozzle may have the same characteristics set out above for the pair of nozzles, in particular with regard to the leakage orifice(s), the upstream edge and / or the downstream edge, the seal, the distance from the disc, the angle of separation from the linings, or the fixing using a tab to the bracket.

[0039] According to another aspect, an auxiliary groove which overlaps the sidewall of the disc connects the two suction grooves together. This auxiliary groove may be narrower than the two suction grooves.

[0040] According to another aspect, the disc is covered with a ceramic coating. The coating may be a tungsten or chromium carbide. Since these types of discs wear less (approximately 0.2 to 0.3 mm of thickness lost between the new state and the worn state, compared to 1 mm for a cast iron disc), the positioning of the nozzles is easier and the efficiency of the suction is maintained throughout the life of the disc.

[0041] The invention also relates to a motor or railway vehicle comprising a brake as described above, in which the control unit receives a signal indicative of the speed of the vehicle and the suction means are controlled to remain inactive if the speed of the vehicle is below a threshold. It is thus possible to avoid the suction of water when crossing a ford. Brief description of the drawings

[0042] Other characteristics, details and advantages will appear on reading the detailed description below, and on analyzing the attached drawings, in which:

[0043] [Fig.l] shows a vehicle, a disc brake and a particle capture system.

[0044] [Fig.2A] shows a flowchart of a method of implementing the capture system.

[0045] [Fig.2B] shows a timing diagram of the process of [Fig.2A].

[0046] [Fig.3] illustrates three examples of brake pads.

[0047] [Fig.4] illustrates an isometric view of a disc brake.

[0048] [Fig.5] represents an isometric view of a suction nozzle.

[0049] [Fig.6] shows a sectional view of the suction nozzles mounted around the disc.

[0050] [Fig.7] schematically illustrates a front view of the positioning of the nozzles.

[0051] [Fig.8] shows an alternative design for a nozzle.

[0052] [Fig.9] shows an alternative design for a nozzle.

[0053] [Fig. 10] illustrates an example of a single nozzle accommodating two grooves. Description of the embodiments

[0054] The figures represent different aspects of the invention in a schematic manner. Unless explicitly indicated otherwise, each aspect shown in a figure can be combined with other aspects shown in other figures in any combinations technically possible.

[0055] [Fig.l] illustrates a possible application for the present disclosure. A vehicle 1, road (car, van, truck, etc.) or rail (train, tram, metro, etc.), comprises a braking device 2 of the disc brake type. It is understood that the invention is not limited to this type of vehicle or to this type of brake: indeed, those skilled in the art will know how to adapt the invention for other vehicles (motorcycle, bicycles, etc.) or for other types of brakes (drum, multi-disc, etc.).

[0056] The brake 2 is essentially composed of a disc 4 secured to a wheel of the vehicle 1 and rotating at a rotational speed denoted W around an axis 6. The rotational speed W is proportional to the linear speed V of advance of the vehicle 1. A caliper 8 partially overlapping the periphery of the disc 4 contains two brake pads formed of a base and a lining 10, 12. For example, the pads may be those shown in [Fig. 3] and inspired by [Fig. 1] of the document FR 3 087 238 A1, by figure 3A of the document GB 2 533 476 A or by figures 3 or 4 of the document KR 2020 0016 690 A. The application of a force parallel to the axis 6 by means of one or more pistons generates a braking torque by the friction of the linings 10, 12 on the respective sides of disc 4.

[0057] During a braking operation, the friction of the linings 10, 12 on the disc 4 generates particles (dust, PM10, PM2.5, etc.). These particles are harmful to the environment: their composition may contain elements that are difficult for the environment to assimilate and harmful to the respiratory functions of people who are exposed to them on a recurring basis.

[0058] A particle capture system 20 is thus provided for recovering the particles. Such a system 20 may for example be in the form presented in document FR 3 057 040 A1 or in another form, in particular according to the examples in the patent literature published in the name of the company Tallano Technologie(s).

[0059] The capture system 20 may thus comprise a vacuum source 22, here represented as a turbine, which is fluidically connected, for example by means of a (flexible) pipe 24, to a zone close to the interface between the linings 10, 12 and the disc 4. In one example, the linings 10, 12 may be provided with a through hole and the pipe 24 may be connected to the rear face of the linings 10, 12. The pipe 24 may comprise a filter 26 or a particle collection tank. This filter 26 may for example be sized so as not to require maintenance and so as to be able to be replaced simultaneously with a replacement of the linings 10, 12. The filter 26 may be arranged downstream or upstream of the turbine 22.

[0060] The operation of the turbine 22 can be controlled, via a connection 28, by a control unit 30. The control unit 30 is shown schematically here. It can comprise a memory, a processor and communication buses nication. It can take the form of hardware and / or software elements dedicated to controlling the capture system or be integrated into one of the vehicle's main controllers (CAN, ECU, EMS, etc.).

[0061] The control unit 30 controls the amount of current that is supplied to the motor of the turbine 22 and thus controls its speed. When no electric current is supplied to the motor driving the turbine 22, the turbine 22 is stationary and no vacuum is created in the conduit 24. No suction of particles is produced. In this case, the suction means 20, 22, 24, 26 are said to be in an inactive state. When an electric current is supplied to the motor driving the turbine 22, the latter starts moving and suction is produced. In this case, the suction means 20, 22, 24, 26 are said to be in an active state, regardless of the (non-zero) speed of the turbine and / or the (non-zero) amplitude of electric current supplied to the motor.

[0062] In a variant, the active or inactive state of the suction means is regulated by a valve arranged in the pneumatic suction circuit and the turbine can be driven continuously.

[0063] [Fig.2A] illustrates a method 100 for implementing the capture system 20 of [Fig.1]. In a first step 110 of a first duration T1, the suction means are controlled to be active. In a second step 120 of a second duration T2, the suction means are controlled to be inactive.

[0064] The two steps 110, 120 form a cycle C which is repeated. The two steps follow one another directly in time.

[0065] This succession in time is also represented in [Fig.2B]. The abscissa axis is the time axis. The curve shows the slots corresponding to the changes of state between the active state and the inactive state, each of the states being maintained for a respective duration T1, T2.

[0066] The following table shows the quantities of PM 10 particles detected (produced by the brake and not captured) during a standardized WLTP cycle, according to different suction configurations (in mg per km and per vehicle brake): Standard pad without suction groove or hole Pad with a collection groove No suction Continuous suction Suction during braking phases only No suction 8.0 1.8 2.7 3.8 Table 1

[0067] It is observed that the simple fact of presenting a collection groove halves the quantity of particles escaping into the environment. This confirms the fact that it is not essential to suck up the particles precisely during braking to obtain an impact on the captured particles. Of course, if no suction is ever carried out, the groove fills up and its ability to serve as a reservoir disappears.

[0068] The above tests were conducted with a groove arranged in a downstream portion of the brake lining, i.e. the portion of the lining last seen by a given point on the disc in its trajectory. This is the generally optimal arrangement for collecting particles that have been torn from the lining.

[0069] Other tests, carried out by placing a groove in the upstream part of the lining (or carried out with the same system but with an opposite direction of rotation of the disc) have shown that continuous suction or only during braking phases made it possible to capture approximately 40% of the particles produced. This means that it is possible to capture particles which have not just been torn from the lining. In all probability, these particles are therefore those which are deposited in the asperities of the disc.

[0070] The following table shows the quantities of PM 10 particles detected (produced by the brake and not captured) during a standardized WLTP cycle, according to different suction configurations (in mg per km and per vehicle brake): No suction (standard pad) Continuous suction Suction during braking phases only Cyclic suction (Tl=1min; T2=6min) 8.0 1.8 2.7 2.6 Table 2

[0071] It appears that cyclic suction is as effective as suction that is limited to braking sequences. The capture is approximately 67% of the PM10 particles produced. Cyclic suction makes it possible to choose a lower turbine acceleration, because it is not necessary to quickly increase the turbine speed to absorb the particle peak that occurs during braking. Thus, for the same particle capture rate, a smaller motor can be chosen.

[0072] The following table shows the quantities of PM 10 particles detected (produced by the brake and not captured) during a standardized WLTP cycle, for different suction configurations (in mg per km and per vehicle brake): Continuous suction Cyclic suction (Tl=lmin; Cyclic suction (Tl=lmin; Cyclic suction (Tl=lmin; Cyclic suction (Tl=lmin; T2=3min) T2=6min) T2=13min) T2=27min) 1.8 2.2 2.6 3.6 3.7 Table 3

[0073] Tests with different values ​​of T1 and T2 show that when the T1 / T2 ratio is less than 10%, the quantity of particles detected (produced and not captured) is close to 3.7 mg / km / brake, which is the quantity detected in the absence of suction. For a T1 / T2 ratio between 15% and 30%, the efficiency is acceptable. Beyond 30%, the benefits on particle capture are counterbalanced by significant electrical consumption.

[0074] As regards the values ​​of the durations, the duration Tl can be between 5 seconds and 2 minutes, preferably between 10 seconds and 1 minute. Below this range, it becomes necessary again to provide rapid acceleration of the turbine so that it quickly reaches stationary mode (and therefore a powerful and power-hungry engine) before the end of Tl. Above this range, the electrical consumption is significant.

[0075] The second duration T2 may be between 30 seconds and 30 minutes, preferably between 4 and 10 minutes. For the reasons mentioned above, the duration T2 is chosen so that the ratio between the first duration T1 and the second duration T2 is between 1 / 3 and 1 / 10.

[0076] The values ​​of T1 and T2 can be fixed. Alternatively, they can be adjustable during the life of a brake / vehicle / machine. For example, a degree of wear of the disc can be monitored (material thickness, surface flatness defect (warping)). For example, an operator can measure this degree of wear during a maintenance check and communicate it to the control unit 30. The control unit can be programmed to adjust the durations T1 and T2 according to the wear of the disc, for example so that the ratio T1 / T2 increases with the wear of the disc. Indeed, the wear of the disc can accentuate the surface defects and therefore the quantity of particles which can lodge there. It may be advantageous to suck up the particles for a longer time by increasing T1 (or the ratio T1 / T2).

[0077] It may be possible to condition the activation / deactivation of the suction means on the speed of the vehicle (V in [Fig.l]) or of the disc (W). To do this, a speed detector dedicated to or integrated into the vehicle or machine may be provided. This detector communicates a signal to the control unit indicating the speed of the disc or of the vehicle. The control unit may be programmed to compare the actual speed with a threshold and to keep the suction means deactivated if the speed is below this threshold.

[0078] [Fig.3] shows three examples of brake pads 40, 50, 60 which can be used with the particle capture system. Other variants are also possible.

[0079] The plate 40 comprises a sole 42 on which the lining 10 is fixed. In the lining 10, a particle collection groove 44 is formed. This groove is connected to suction means.

[0080] The plate 50 comprises a peripheral groove 54 which matches the profile of the lining 10. An air inlet is provided in the center of the lining 10 and an air outlet is arranged in the groove 54.

[0081] The plate 60 is formed of a lining 10 and a skirt 62 which is intended to be arranged around the lining 10 to form a suction zone 64 between the lining 10 and the skirt 62.

[0082] Thus, various collection elements 44, 54, 64 can be provided on a plate for the suction of particles.

[0083] Figures 4 to 10 show means for collecting particles which may be an alternative to the grooves 44, 54, 64, or be complementary to them.

[0084] [Fig. 4] shows an isometric view of suction means arranged near the disc 4. The disc 4 comprises, on each side, an annular friction surface 5 delimited by an internal circle C1 of radius RI and an external circle C2 of radius R2. The annular friction surface 5 is the set of points seen by the linings 10, 12 during rotation of the disc 4.

[0085] In this example, the caliper 8 is floating, that is to say it is movable in sliding relative to a yoke 9 fixed to the hub of the wheel. The invention is obviously adaptable to a brake with a fixed caliper.

[0086] In order to suck up the particles lodged in the asperities or on the surface of the disc 4, two nozzles 140 are arranged close to the disc 4, each facing one of the two annular friction surfaces 5. Rigid conduits 148, 149 are provided to, on the one hand, fluidically connect the nozzles 140 to the vacuum source 22 and, on the other hand, to maintain the nozzles 140 in position opposite the disc 4.

[0087] A fixing lug 150 makes it possible to fix the rigid pipes 148, 149 to the yoke 9. The rigid pipes 148, 149 pass through two orifices 152 of the lug 150, with a tight fit. A third orifice makes it possible to fix the lug 150 to the yoke 9. The lug 150 can have a V shape. In a variant, the lug is formed in the yoke 9. The pipes 148, 149 project from the lug 150. They can be connected to the vacuum source 22 by means of hoses (not shown).

[0088] The conduit 148 may have a U shape and the conduit 149 may be straight.

[0089] [Fig. 5] shows an isometric view of a nozzle 140. The nozzle comprises an upstream edge 141 (i.e., which is seen by a point on the disc first) and a downstream edge 142 (seen last). The downstream edge 142 may be provided with a seal (e.g., a brush seal) or elastomer) which scrapes the disc 4. In a variant, or in combination, the downstream edge 142 may be further from the disc than the upstream edge, for example by a distance of at least 50% greater.

[0090] A groove 146 makes it possible to create a suction air flow having a direction mainly perpendicular to the surface 5 of the disc 4. The groove may be parallel to the longitudinal direction A of the nozzle 140. In the circumferential direction, the groove 146 may have a substantially constant width over its entire radial length. The width of the groove 146 may be between 1 and 6 mm, and may preferably be 4 mm. The groove may have a depth of a few millimeters, preferably approximately 0.5 mm. Too great a depth (for example 15 mm) is not relevant for the efficiency of the suction.

[0091] At least one leak orifice 143 may be provided on a rear face of the nozzle. This orifice 143 is in fluid connection with the groove and encourages the creation of a flow having a component in the opposite direction to the direction of movement of the disk, which may have advantages so that the particles do not remain stuck in the groove. The position and number of leak orifices 143 may vary: two orifices 143 may be provided, not only on the downstream face (as drawn in [Fig. 5]) but also on the upstream face of the nozzle 140. A leak orifice 143 may be provided at the rear of the nozzle (the face of the nozzle opposite that which faces the disk). In this configuration, the suction port 147 may be located at one end (along the axis A) of the groove 146, and the leak port 143 may be located at another end of the groove 146.

[0092] The nozzle 140 may have a substantially longitudinal, elliptical or oval shape, with a longitudinal axis A. In a variant not illustrated, the nozzle 140 has a different shape, for example a half-moon.

[0093] The pipe 148, 149 creates a suction in the groove 146. A suction orifice 147 is provided for this purpose in the nozzle 140.

[0094] [Fig.6] shows a sectional view of the installation of the nozzles 140. In this For example, the suction orifice 147 is centered relative to the groove 146 in the longitudinal direction A. The groove 146 of the nozzles 140 faces the friction surfaces 5 of the disc 4. The nozzles 140 are at a distance B from the friction surfaces 5. The distance B may be less than 3 millimeters or even 0.1 millimeters.

[0095] The pipe 148 forms a U and the pipe 149 is straight. In this example, the pipes 148, 149 are coplanar but other designs are possible.

[0096] In the examples of Figures 4 to 6, the nozzles 140 are arranged symmetrically but other arrangements are possible. These may be angularly offset from each other or may be of different design.

[0097] [Fig.7] schematically shows the positioning of the nozzles 140. The fittings 10, 12 may define a median radius RO and the longitudinal axis A of the nozzles 140 may be arranged in alignment with a radius R, angularly offset from the radius RO by an angle a. This angle is preferably between 20° and 160°. The bracket does not always allow a smaller angle to be provided. Too large an angle is not necessarily compatible with the nozzles being fixed by a bracket and may therefore complicate the nozzle fixing.

[0098] Figures 8 and 9 illustrate two design variations of the nozzle 140.

[0099] In [Fig.8], the suction line 148, 149 is parallel to the groove 146. The suction flow has a direction substantially perpendicular to the surface of the disc.

[0100] [Fig.9] shows a pair of nozzles 140 with two leakage ports 143 at both radial ends of the groove 146. Air is drawn in from both the disc side and the ports 143, forcing an airflow into the groove that is parallel to the friction surfaces of the disc.

[0101] [Fig. 10] shows an example in which a single nozzle 140 receives the two grooves 146. This nozzle may have a general U-shape. The suction may be carried out by a single conduit 48, arranged in the plane of the disc. A narrower auxiliary groove 160 may connect the two grooves 146. For example, the circumferential thickness of the auxiliary groove is half the circumferential thickness of the grooves 146. The auxiliary groove 160 overlaps the side of the disc.

[0102] It is understood that the present invention is not limited to the examples described above and that those skilled in the art would be able to envisage variants without departing from the protection conferred by the appended claims.

Claims

Claims

1. Method (100) for implementing a system (20) for capturing braking particles from a disc brake, the capture system (20) comprising particle suction means (22, 24, 26) and a control unit (30) configured to control the active or inactive state of the suction means (22, 24, 26), the method comprising a succession of cycles (C), each of the cycles (C) comprising a first step (110) of a first duration (T1) during which the suction means (22, 24, 26) are controlled by the control unit (30) to be in an active state and a second step (120) of a second duration (T2) during which the suction means (22, 24, 26) are controlled by the control unit to be in an inactive state.

2. Method (100) according to claim 1, wherein the first duration (T1) is between 5 seconds and 2 minutes, preferably between 10 seconds and 1 minute.

3. Method (100) according to claim 1 or 2, wherein the second duration (T2) is between 30 seconds and 30 minutes, preferably between 4 and 10 minutes.

4. Method (100) according to one of claims 1 to 3, in which the ratio between the first duration (T1) and the second duration (T2) is between 1 / 3 and 1 / 10.

5. Method (100) according to one of claims 1 to 4, in which the control unit (30) receives a signal indicative of the rotation speed (W) of the disk (4) and the suction means (22, 24, 26) are controlled to remain inactive if the rotation speed (W) of the disk (4) is below a threshold.

6. A method (100) according to one of claims 1 to 5, wherein a degree of wear of the disc is monitored, and the first and second durations (T1, T2) are adjusted such that the ratio between the first duration (T1) and the second duration (T2) increases with wear of the disc.

7. Method (100) according to one of claims 1 to 6, in which the brake comprises a pair of linings (10, 12), each having a particle collection element (44, 54, 64), the suction means (22, 24, 26) of the particle capture system (20) being fluidically connected to the particle collection elements (44, 54, 64).

8. Method (100) according to one of claims 1 to 7, in which the brake comprises a pair of linings (10, 12); a disc (4) having two annular friction surfaces (5), respective locations of friction of the linings (10, 12) on the disc (4), each of the annular friction surfaces (5) being delimited by an internal circle (Cl) and an external circle (C2); and the particle capture system (20) comprises two grooves (146) fluidically connected to the vacuum source (22) and arranged at a distance from the friction linings (10, 12), each of the grooves (146) being arranged opposite a respective annular friction surface (5), each groove (146) extending from the internal circle (Cl) to the external circle (C2).

9. System (20) for capturing braking particles emitted by a disc brake (2), the capture system (20) comprising: - particle suction means (22, 24, 26) capable of assuming an active or inactive state; and - a control unit (30) configured to switch the suction means (22, 24, 26) alternately between an active state and an inactive state in accordance with the method of one of the preceding claims.

10. Disc brake (2) comprising a particle capture system (20) according to claim 9 and in which the active or inactive state of the suction means (22, 24, 26) is regulated independently of the activation of the brake (2).

11. Brake (2) according to claim 10 comprising a pair of brake linings (10, 12), each having a particle collection element (44, 54, 64), the suction means (22, 24, 26) of the particle collection system (20) being fluidically connected to the particle collection elements (44, 54, 64).

12. Brake according to claim 10 or 11 comprising a pair of linings (10, 12); and a disc (4) having two annular friction surfaces (5), respective locations of friction of the linings (10, 12) on the disc (4), each of the annular friction surfaces (5) being delimited by an internal circle (C1) and an external circle (C2), the particle capture system (20) comprising two suction grooves (146) fluidically connected to the vacuum source (22) and arranged at a distance from the friction linings (10, 12), each of the grooves (146) being arranged opposite a respective annular friction surface (5), each groove (146) extending from the internal circle (C1) to the outer circle (C2).

13. A brake according to claim 12, wherein each groove (146) is substantially rectilinear and has a width measured in a circumferential direction which is between 1 and 6 mm, and which is preferably 2 or 4 mm.

14. A brake according to either of claims 12 or 13, wherein each groove (146) is arranged in a respective nozzle (140).

15. Brake according to claim 14, in which each nozzle (140) has at least one leakage orifice (143) in fluid connection with the groove (146).

16. Brake according to one of claims 14 or 15, in which each nozzle (140) is arranged at an axial distance (B) of less than three millimeters, preferably less than 0.1 mm, from the respective annular friction surface (5).

17. Brake according to one of claims 14 to 16, in which each nozzle (140) comprises a downstream edge (42) provided with a seal (44) or a brush in contact with the respective annular friction surface.

18. Brake according to one of claims 14 to 17, wherein each nozzle (140) comprises an upstream edge (141) and a downstream edge (142), the downstream edge (142) being further from the respective annular friction surface (5) than the upstream edge (141).

19. Brake according to one of claims 14 to 18, in which the groove (146) of each nozzle (140) has a longitudinal direction (A) which is arranged in alignment with a radius (R) of the disc (4), said radius (R) being preferentially angularly offset from a median radius (R0) of the linings (10, 12), by an angle (a) of between 20° and 60°.

20. Brake according to one of claims 14 to 19, wherein the brake (2) comprises a fixed caliper or a floating caliper (8) sliding relative to a yoke (9), the nozzles (140) being fixed to the fixed caliper or to the yoke (9).

21. Brake according to one of claims 14 to 20, in which the particle capture system (20) comprises two rigid pipes (148, 149) each connected to a respective nozzle (140) and by means of which the nozzles (140) are held in position opposite the disc (4).

22. Brake according to claims 20 and 21, in which a fixing lug (150) connects the rigid pipes (148, 149) to the caliper or to the yoke (9), the fixing lug (150) comprising two orifices (152) crossed by the rigid pipes (148, 149).

23. Brake according to one of claims 12 or 13, in which the two grooves (146) are arranged in a single nozzle (140).

24. A brake according to claim 23, wherein an auxiliary groove (160) which overlaps the disc flank connects the two suction grooves (146) together.

25. Brake according to one of claims 10 to 24, in which the disc (4) is covered with a ceramic coating.

26. Motor or railway vehicle (1) comprising a brake according to one of claims 10 to 25, in which the control unit (30) receives a signal indicative of the speed of the vehicle (V) and the suction means (22, 24, 26) are controlled to remain inactive if the speed of the vehicle (V) is below a threshold.

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