Brake particle capture method and system

Abstract

Disclosed is a method for implementing a system (20) for capturing brake particles from a disc brake, the capture system (20) comprising particle suction means (22, 24, 26) and a control unit (30) configured to control whether the suction means (22, 24, 26) are in the active or inactive state, 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) in order 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 in order to be in an inactive state.

Description

Description Title: METHOD AND SYSTEM FOR CAPTURING BRAKING PARTICLES Technical field

[0001] This disclosure relates to the field of vehicle braking devices (automobiles or railways) or industrial braking devices. The context relates in particular to the environmental protection aspects by the suction of braking particles emitted by friction brakes, in particular disc 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 maximum suction is controlled during braking.

[0004] Document FR 3 088 395 A1 introduces the concept of suction compensation depending on 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 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 particles, the suction means must therefore react quickly to the start of braking: a powerful motor is necessary to ensure sufficient acceleration of the suction turbine, 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 when the turbine accelerates.

[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. However, this solution has the disadvantage of over-activation of the particle collection system. Indeed, 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 efficient suction of braking particles without using a powerful and expensive motor whose rotation would create significant peaks in electricity 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 shown that, surprisingly, activating and deactivating the suction regularly, independently of the brake activation, allows a significant and sufficient level of particles to be captured. 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 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 brake activation 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 power consumption.

[0010] Cyclic activation and deactivation should 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, while the “inactive” state corresponds to an absence of suction.

[0012] The "suction means" comprise one or more elements configured to create a negative pressure flow in the vicinity of the interface between the disc and the friction lining. The documents cited above give examples of structures for generating this negative pressure flow. Examples include: a caliper cover, a suction nozzle, a lining with a groove and a through-hole. The source of negative 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 providing the system 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" we mean a hardware and / or software element dedicated to controlling the capture system or integrated into one of the main controllers of the vehicle (CAN, ECU, EMS, etc.) or the industrial machine.

[0014] Furthermore, it is implicit that the first and second durations are non-zero, otherwise the aspiration 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] In another aspect, a degree of wear of the disk 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 disk.

[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 inner circle and an outer 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 inner circle to the outer 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 collection 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 fluidically 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 meant 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 (e.g. + / - 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. Alternatively, 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, i.e. the first edge that a point of the disc “sees” during its rotation, can be at a distance from the disc while the downstream edge, provided with the seal, is in contact with the disc. This seal makes it possible to scrape off any particles to further improve their suction.

[0033] In another aspect, each nozzle includes an upstream edge and a downstream edge, the downstream edge being further from the respective annular friction surface than the upstream edge. This allows air to be drawn downstream of the nozzle and initiates a flow in the direction opposite 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] In another aspect, a mounting bracket connects the rigid pipes to the bracket or yoke, the mounting bracket comprising two holes through which the rigid pipes pass.

[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 attachment using a tab to the bracket.

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

[0040] In another aspect, the disc is covered with a ceramic coating. The coating can be tungsten or chromium carbide. Since these types of discs wear less (approximately 0.2 to 0.3 mm of thickness lost between new and worn, compared to 1 mm for a cast iron disc), the positioning of the nozzles is easier and the suction efficiency 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 vehicle speed is below a threshold. It is thus possible to avoid water suction when crossing a ford. Brief description of the drawings

[0042] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analyzing the attached drawings, in which:

[0043] [Fig. 1] shows a vehicle, a disc brake and a particle capture system.

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

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

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

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

[0048] [Fig. 5] shows 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 nozzle positioning.

[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 may be combined with other aspects shown in other figures in any technically possible combination.

[0055] Figure 1 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 figure 3 and inspired by figure 1 of document FR 3 087 238 A1, figure 3A of document GB 2 533 476 A or figures 3 or 4 of 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 faces of the 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. It can take the form of hardware and / or software elements dedicated to the control of the capture system or be integrated into one of the main controllers of the vehicle (CAN, ECU, EMS, etc.).

[0061] The control unit 30 controls the amount of current 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 one 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] Figure 2A illustrates a method 100 for implementing the capture system 20 of Figure 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 each other directly in time.

[0065] This succession in time is also represented in Figure 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 PM10 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): Table 1

[0067] It has been observed that simply having a collection groove halves the amount of particles escaping into the environment. This confirms the fact that it is not essential to vacuum up particles precisely during braking to have an impact on the captured particles. Of course, if no vacuuming 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 path. 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 the disc rotating in the opposite direction) have shown that continuous suction or suction only during braking phases allows the capture of approximately 40% of the particles produced. This means that it is possible to capture particles that have not just been torn from the lining. In all probability, these particles are therefore those that are deposited in the roughness of the disc.

[0070] The following table shows the quantities of PM10 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): 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 allows for a lower turbine acceleration to be chosen, as it is not necessary to quickly ramp up the turbine to absorb the particle peak that occurs during braking. Thus, for the same particle capture rate, a smaller engine 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): Table 3

[0073] Tests with different T1 and T2 values 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. Above 30%, the benefits on particle capture are offset by significant power consumption.

[0074] As for the duration values, the duration T 1 can be between 5 seconds and 2 minutes, preferably between 10 seconds and 1 minute. Below this range, it becomes necessary 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 T1. Above this range, the electrical consumption is significant.

[0075] The second duration T2 can 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 over the life of a brake / vehicle / machine. For example, a degree of disc wear 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 disc wear, for example so that the T1 / T2 ratio increases with disc wear. Indeed, disc wear can accentuate surface defects and therefore the quantity of particles that can lodge there. It may be advantageous to suck up the particles for a longer time by increasing T1 (or the T1 / T2 ratio).

[0077] It may be possible to condition the activation / deactivation of the suction means on the speed of the vehicle (V in Figure 1) 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 the vehicle. The control unit can 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] Figure 3 shows three examples of brake pads 40, 50, 60 that 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] Figure 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 R1 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 pipes 148, 149 are provided to, on the one hand, fluidly 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] Pipe 148 may be U-shaped and pipe 149 may be straight.

[0089] Figure 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 (for example, a brush or elastomer) which scrapes the disc 4. Alternatively, or in combination, the downstream edge 142 may be further from the disc than the upstream edge, for example by a distance 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 disc, 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 disc). In this configuration, the suction orifice 147 may be located at one end (along the axis A) of the groove 146, and the leak orifice 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] Figure 6 shows a sectional view of the installation of the nozzles 140. In this 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] Pipe 148 forms a U and pipe 149 is straight. In this example, 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] Figure 7 shows schematically the positioning of the nozzles 140. The fittings 10, 12 can define a median radius R0 and the longitudinal axis A of the nozzles 140 can be arranged in alignment with a radius R, angularly offset from the radius R0 by an angle a. This angle is preferably between 20° and 160°. The bracket does not always allow a greater angle to be provided. small. Too large an angle is not necessarily compatible with fixing the nozzles using a bracket and can therefore complicate the fixing of the nozzles.

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

[0099] In Figure 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] Figure 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] Figure 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 provided by a single pipe 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, in which 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, wherein 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, wherein 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 inner circle (C1) and an outer circle (C2); and the particle capture system (20) comprises two grooves (146) fluidly 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 inner circle (C1) to the outer 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 inner circle (C1) and an outer circle (C2), the particle capture system (20) comprising two suction grooves (146) fluidly 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 inner 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 (RO) 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.

Images