METHOD AND SYSTEM FOR CAPTURING BRAKE PARTICLES

Abstract

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 the active or inactive state of the suction means (22, 24, 26), the method comprising a succession of cycles, each cycle comprising a first stage of 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 stage of 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 BRAKE PARTICLES technical field

[0001] This disclosure relates to the field of vehicle braking systems (automobiles or railways) or industrial braking systems. The context specifically addresses environmental protection aspects related to the extraction of brake particles emitted by friction brakes, particularly disc brakes. Previous technique

[0002] Document FR 3 057 040 A1 describes a disc brake lining equipped with a collection groove and a through orifice, fluidly connected to suction means. This lining allows for the efficient suction of brake dust along its entire radial height. The suction means include a turbine generating a vacuum that draws in the dust and directs it to a collection filter.

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

[0004] Document FR 3 088 395 Al introduces the concept of compensating the suction based on the level of filling 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 it afterward. 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 devices must therefore react quickly to the onset of braking: a powerful motor is necessary to ensure sufficient acceleration of the suction turbine, allowing it to reach operating speed as quickly as possible to capture the maximum number of particles formed during this peak. Motors powerful enough to achieve appropriate acceleration curves are expensive and generate a significant electrical current draw during 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. However, this solution has the drawback of over-activating the collection system. particles. Indeed, the friction brake is not always activated when regenerative braking is used. Furthermore, this solution is only feasible for vehicles equipped with regenerative braking. Summary

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

[0008] A method for implementing a brake particle capture system for a disc brake is thus proposed, 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 stage of a first duration during which the suction means are controlled by the control unit to be in an active state and a second stage 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, regularly activating and deactivating the suction, independently of brake activation, allows for the capture of a significant and sufficient level of particles. Without being bound by theory, these good results appear to stem from two factors. The first factor seems to be that the suction area of ​​the brake pad (for example, a groove on the trailing edge of the pad or a peripheral groove) can act as a reservoir for particles during braking, even in the absence of suction. The second factor is that during suction, particles stored in the disc's irregularities are drawn in, whether the suction occurs during brake activation or in the absence of braking.By activating the suction cyclically, that is, independently of brake activation, we eliminate the need to rapidly activate the suction during braking to absorb particles at the peak discussed above. Consequently, there is no longer a need to equip the system with a powerful motor that generates spikes in electrical consumption.

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

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

[0012] The "suction means" comprise one or more elements configured to create a vacuum flow in the vicinity of the interface between the disc and the lining of friction. The documents cited above provide examples of structures for generating this vacuum flow. Examples include: a caliper cover, a suction nozzle, and a lining with a groove and a through orifice. The vacuum source can be a turbine driven by a motor. The "active" state corresponds to a running motor, and the "inactive" state corresponds to a stopped motor. The process described here therefore alternates between driving and stopping the motor and no longer requires equipping the system with a powerful motor that must ensure rapid acceleration upon detection of the onset of braking. Thus, a smaller, less expensive, lighter, and less power-hungry motor can be used for the system.

[0013] By "control unit", it is appropriate to understand 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,...) or of 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 collection system of this disclosure is also capable of capturing particles from other types of brakes, 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 an indicator signal of the disc's rotational speed, and the suction means are commanded to remain inactive if the disc's rotational speed is below a threshold. This is particularly advantageous for a brake fitted to a vehicle: suction can be risky at low speeds when the vehicle is fording a stream, since water can enter the suction circuit. Above a certain speed, this risk no longer exists. Tests have shown that driving in the rain does not present this risk of water being drawn into the pneumatic circuit. The threshold speed can depend on the vehicle in question and can be on the order of 2 to 3 revolutions per second (from 25 to 30 km / h).

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

[0021] According to another aspect, the brake comprises a pair of linings; a disc having two annular friction surfaces, the respective locations of the 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 fluidly connected to the source of vacuum and disposed at a distance from the friction linings, each of the grooves being disposed 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 brake 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 fluidly 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, the respective locations of the 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 brake particle capture system comprising: a vacuum source; and two suction grooves fluidly connected to the vacuum source and disposed at a distance from the friction linings, each of the grooves being disposed 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 should be understood that the groove, when the disk rotates, overhangs 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 and outer circles.

[0027] According to another aspect, each groove is substantially straight 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 can 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 leakage orifice in fluidic contact with the groove. Such an orifice allows an airflow to be initiated in the opposite direction to the direction of movement of the disc. In one embodiment, the nozzle comprises two orifices on two opposite faces (upstream and downstream) of the nozzle. In another embodiment, two leakage orifices may be provided on a rear face of the nozzle, with suction then being achieved through a suction orifice centered with respect to the two leakage orifices, in order to minimize the path traveled by the air in the grooves and promote suction efficiency.

[0031] According to another aspect, each nozzle is disposed 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 includes a downstream edge fitted 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 on the disc "sees" during its rotation, can be some distance from the disc, while the downstream edge, fitted with the seal, is in contact with the disc. This seal allows for the scraping of 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 allows air to be drawn in downstream of the nozzle and initiates a flow in the opposite direction to the movement of the disk.

[0034] According to another aspect, the groove of each nozzle has a longitudinal direction aligned with a radius of the disc, said radius being preferably offset angularly from a median radius of the brake pads by an angle between 20° and 60°. This angle defines the clearance between the pads and the nozzles. Too small an angle imposes constraints on the nozzle design due to the proximity of the caliper. Too large an angle complicates the nozzle attachment, as they can no longer be reattached to the caliper.

[0035] According to another aspect, the brake comprises a fixed caliper or a floating caliper sliding relative to a bracket, the nozzles being fixed to the fixed caliper or the bracket. This notably avoids a complex system for attaching the nozzles to the vehicle.

[0036] According to another aspect, the particle capture system comprises two rigid pipes 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 bracket connects the rigid pipes to the stirrup or clevis, the fixing bracket comprising two orifices through which the rigid pipes pass.

[0038] According to another aspect, the two grooves are arranged in a single nozzle. This A single nozzle can have the same characteristics described above for a pair of nozzles, particularly with regard to the leakage orifice(s), the upstream and / or downstream edge, the seal, the distance to the disc, the angle of departure from the linings, or the attachment using a tab to the caliper.

[0039] According to another aspect, an auxiliary groove that overlaps the side 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 coated 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 the new and worn states, compared to 1 mm for a cast iron disc), the positioning of the nozzles is easier and the suction efficiency is maintained throughout the disc's life.

[0041] The invention also relates to a motor vehicle or railway vehicle comprising a brake as described above, in which the control unit receives a signal indicating the vehicle's speed and the suction means are controlled to remain inactive if the vehicle's speed is below a threshold. This makes it possible to avoid water intake when fording a stream. Brief description of the drawings

[0042] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which:

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

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

[0045] [Fig.2B] shows a chronogram 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 cross-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] represents a design variant for a nozzle.

[0052] [Fig.9] shows a design variant for a nozzle.

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

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

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

[0056] The brake 2 essentially consists of a disc 4 attached to a wheel of the vehicle 1 and rotating at a rotational speed denoted W about an axis 6. The rotational speed W is proportional to the linear speed V of the vehicle 1. A caliper 8 partially overlapping the periphery of the disc 4 contains two brake pads consisting of a backing plate and a lining 10, 12. For example, the pads could be those shown in [Fig. 3] and based on [Fig. 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. Applying a force parallel to the axis 6 by means of one or more pistons generates a braking torque through the friction of the linings 10, 12 on the surfaces respective of disc 4.

[0057] During braking, the friction of the brake pads 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 are harmful to the respiratory functions of people who are repeatedly exposed to them.

[0058] A particle capture system 20 is thus provided to recover the particles. Such a system 20 may, for example, be in the form shown in document FR 3 057 040 Al 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 collection system 20 can thus include a vacuum source 22, here represented as a turbine, which is fluidically connected, for example by means of a flexible conduit 24, to an area near the interface between the seals 10, 12 and the disc 4. In one example, the seals 10, 12 may have a through hole and the conduit 24 may be connected to the rear face of the seals 10, 12. The conduit 24 may include a filter 26 or a particle collection tank. This filter 26 may, for example, be sized to be maintenance-free and to be replaced simultaneously with the replacement of the seals 10, 12. The filter 26 may be located upstream or downstream 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 here schematically. It may include memory, a processor, and communication buses. Information. 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,...).

[0061] The control unit 30 controls the amount of current supplied to the turbine motor 22 and thus controls its speed. When no electrical current is supplied to the motor driving the turbine 22, the turbine 22 is stationary and no vacuum is created in the duct 24. No particle suction is produced. In this case, the suction means 20, 22, 24, 26 are said to be in an inactive state. When an electrical current is supplied to the motor driving the turbine 22, the turbine 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 the electrical current supplied to the motor.

[0062] In one variant, the active or inactive state of the suction means is regulated by a valve disposed 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 activated. In a second step 120 of a second duration T2, the suction means are deactivated.

[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 over time is also represented in [Fig. 2B]. The x-axis is the time axis. The curve shows the intervals corresponding to the changes of state between the active state and the inactive state, each state 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 brake pad without groove or suction port. Brake 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 simply presenting a collection groove halves the quantity of particles escaping into the environment. This confirms that it is not essential to specifically suction the particles during braking to have an impact on the captured particles. Of course, if no suction is ever performed, the groove fills up and its ability to serve as a reservoir disappears.

[0068] The above tests were carried out with a groove located 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 generally the optimal arrangement for collecting the particles that have been torn from the lining.

[0069] Other tests, conducted 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), showed that continuous suction or suction only during braking phases made it possible to capture approximately 40% of the particles produced. This means that it is possible to capture particles that have not just been removed from the lining. In all likelihood, these particles are therefore those that settle in the disc's irregularities.

[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 (T1=1 min; T2=6 min) 8.0 1.8 2.7 2.6 Table 2

[0071] It appears that cyclic suction is as effective as suction limited to braking sequences. Capture is approximately 67% of the PM10 particles produced. Cyclic suction allows for a lower turbine acceleration, as it is not necessary to rapidly increase the turbine speed to absorb the particle peak that occurs during braking. Thus, for the same particle capture rate, a smaller engine can be selected.

[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 but 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 in particle capture are offset by significant power consumption.

[0074] Regarding the duration values, the duration Tl can be between 5 seconds and 2 minutes, preferably between 10 seconds and 1 minute. Below this range, it becomes necessary to provide for a rapid acceleration of the turbine so that it quickly reaches steady state (and therefore requires a powerful and energy-intensive motor) before the end of Tl. 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 adjusted during the service life of a brake / vehicle / machine. For example, the degree of disc wear can be monitored (material thickness, surface flatness defects (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 disc wear, for example, so that the T1 / T2 ratio increases with disc wear. Indeed, disc wear can accentuate surface defects and therefore the amount of particles that can become lodged there. It can be advantageous to extract particles for a longer period 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 [Fig. 1]) or the disc (W). To this end, a dedicated speed sensor or one integrated into the vehicle or machine may be provided. This sensor communicates a signal to the control unit indicating the speed of the disc or vehicle. The control unit can be programmed to compare the actual speed to 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 which can be used with the particle capture system. Other variants are also possible.

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

[0080] The plate 50 includes a peripheral groove 54 which follows 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 trim 10 and a skirt 62 which is intended to be arranged around the trim 10 to form a suction zone 64 between the trim 10 and the skirt 62.

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

[0083] Figures 4 to 10 show means of collecting particles which can be an alternative to grooves 44, 54, 64, or 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 inner circle C1 of radius RI and an outer circle C2 of radius R2. The annular friction surface 5 is the set of points seen by the linings 10, 12 during the rotation of the disc 4.

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

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

[0087] A mounting bracket 150 allows the rigid pipes 148, 149 to be fixed to the bracket 9. The rigid pipes 148, 149 pass through two openings 152 in the bracket 150, with a tight fit. A third opening allows the bracket 150 to be fixed to the bracket 9. The bracket 150 may be V-shaped. In one embodiment, the bracket is formed in the bracket 9. The pipes 148, 149 protrude from the bracket 150. They can be connected to the vacuum source 22 by means of flexible hoses (not shown).

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

[0089] Figure 5 shows an isometric view of a nozzle 140. The nozzle comprises an upstream edge 141 (i.e., the edge seen by a point on the disk first) and a downstream edge 142 (the edge 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 creates a suction airflow with a direction primarily 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 along its entire radial length. The width of the groove 146 may be between 1 and 6 mm, and preferably 4 mm. The groove may have a depth of a few millimeters, preferably about 0.5 mm. A depth that is too great (for example, 15 mm) is not relevant to suction efficiency.

[0091] At least one leakage orifice 143 may be provided on a rear face of the nozzle. This orifice 143 is fluidically connected to the groove and encourages the creation of a flow having a component opposite in direction to the direction of movement of the disc, which can be advantageous in preventing particles from becoming trapped in the groove. The position and number of leakage orifices 143 may vary: two orifices 143 may be provided not only on the downstream face (as shown in [Fig. 5]) but also on the upstream face of the nozzle 140. One leakage orifice 143 may be provided at the rear of the nozzle (the face of the nozzle opposite the one facing the disc). In this configuration, the suction port 147 can be located at one end (along axis A) of the groove 146, and the leakage port 143 can be located at the other end of the groove 146.

[0092] The nozzle 140 can have a substantially longitudinal, elliptical or oval shape, with a longitudinal axis A. In an unillustrated variant, the nozzle 140 has a different shape, for example half-moon shaped.

[0093] The conduit 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 cross-sectional view of the nozzle installation 140. In this For example, the suction orifice 147 is centered with respect 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 can be less than 3 millimeters or even 0.1 millimeter.

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

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

[0097] Figure 7 schematically shows the positioning of the nozzles 140. The fittings 10 and 12 can define a median radius RO, and the longitudinal axis A of the 140 nozzles can be aligned with a radius R, angularly offset from the radius RO by an angle α. This angle is preferably between 20° and 160°. The bracket does not always allow for a smaller angle. An angle that is too large is not necessarily compatible with nozzle mounting by a tab and can therefore complicate nozzle mounting.

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

[0099] In [Fig.8], the suction conduit 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 orifices 143 at the two radial ends of the groove 146. Air is drawn in both from the side of the disc and at the orifices 143, which forces 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-shaped form. Suction may be achieved 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 a person skilled in the art could consider variants without departing from the protection conferred by the attached claims.

Claims

Demands

1. Method (100) of implementing a braking particle capture system (20) for 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 (Tl) 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 any one of claims 1 to 3, wherein the ratio between the first duration (T1) and the second duration (T2) is between 1 / 3 and 1 / 10.

5. A method (100) according to any one of claims 1 to 4, wherein the control unit (30) receives an indicator signal 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 any one of claims 1 to 5, wherein a degree of disc wear is monitored, and the first and second durations (T1, T2) are adjusted in such a way that the ratio between the first duration (T1) and the second duration (T2) increases with disc wear.

7. Method (100) according to any 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 collection system (20) being fluidly connected to the particle collection elements (44, 54, 64).

8. A method (100) according to any 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 (Cl) and an outer circle (C2); and the particle capture system (20) comprises two grooves (146) fluidly connected to the vacuum source (22) and disposed at a distance from the friction linings (10, 12), each of the grooves (146) being disposed opposite a respective annular friction surface (5), each groove (146) extending from the inner circle (Cl) to the outer circle (C2).

9. System (20) for capturing brake particles emitted by a disc brake (2), the capture system (20) comprising: - means for suctioning particles (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 wherein 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 fluidly connected to the particle collection elements (44, 54, 64).

12. A brake according to claim 10 or 11 comprising a pair of linings (10, 12); and a disc (4) having two annular friction surfaces (5), the 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 collection system (20) comprising two suction grooves (146) fluidly connected to the vacuum source (22) and disposed at a distance from the friction linings (10, 12), each of the grooves (146) being disposed opposite a respective annular friction surface (5), each groove (146) extending from the inner circle (C1) to the outer circle (C2).

13. Brake according to claim 12, wherein each groove (146) is substantially straight 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. Brake according to any one of claims 12 or 13, wherein each groove (146) is arranged in a respective nozzle (140).

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

16. Brake according to any one of claims 14 or 15, wherein each nozzle (140) is disposed 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 any one of claims 14 to 16, wherein 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 any 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 away from the respective annular friction surface (5) than the upstream edge (141).

19. Brake according to any one of claims 14 to 18, wherein 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 preferably angularly offset from a median radius (R0) of the linings (10, 12), by an angle (a) between 20° and 60°.

20. Brake according to any 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 any one of claims 14 to 20, wherein the particle capture system (20) comprises two rigid conduits (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, wherein a fixing lug (150) connects the rigid pipes (148, 149) to the caliper or clevis (9), the fixing lug (150) comprising two orifices (152) through which the rigid pipes (148, 149) pass.

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

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

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

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

Images