ASSEMBLY FOR VEHICLE AND CORRESPONDING METHODS

Abstract

Assembly (100) for a vehicle (1) comprising: N disc brakes (2) and a brake dust collection system (20) including: a single vacuum source (22); a pneumatic circuit (24, 26, 32, 34, 36, 38) extending from the vacuum source (22) to the N brakes (2); and a control unit (30) configured to fluidly connect the vacuum source (22) to each of the N brakes (2) sequentially. Abstract figure: Figure 1

Description

Title of the invention: VEHICLE ASSEMBLY AND CORRESPONDING METHODS technical field

[0001] This disclosure relates to the field of vehicle braking systems (automobiles or railways). 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 suction during braking phases and deactivating suction after braking phases. Furthermore, existing systems use a vacuum source for each brake, which makes these designs complex, expensive, and cumbersome. Summary

[0006] The present disclosure improves the situation by proposing a braking system that is simpler and just as effective at sucking up particles.

[0007] A vehicle assembly is thus proposed comprising: N disc brakes, where N is an integer greater than or equal to two, each of the N disc brakes being equipped with a particle collection element; and a brake particle collection system comprising: a single vacuum source; a pneumatic circuit extending from the vacuum source to the collection elements of each of the N brakes; and a control unit configured to fluidly connect the vacuum source to each of the N brakes successively according to a predefined cycle, such that at any At a given instant t, only n(t) brakes are fluidly connected to the source of depression, where for any t, n(t) is an integer between 0 and Nl.

[0008] The inventors have demonstrated that, surprisingly, cyclically (rather than continuously or upon brake activation) aspirating particles 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 collection element (for example, a trailing edge groove on the brake pad, a peripheral groove, a central suction orifice, a caliper cover, a suction nozzle, a network of grooves in the brake pad, etc.) can act as a particle reservoir during braking phases, even in the absence of suction. The second factor is that during suction, particles stored in the disc's asperities are drawn in, whether the suction occurs during brake activation or in the absence of braking.By activating suction cyclically on a brake, that is, independently of brake activation, it becomes possible to use a single suction source to remove particles from multiple brakes without requiring that source to be more powerful. Indeed, without this cyclical suction, using a single suction source for multiple brakes would require that source to be as many times more powerful as there are brakes. An excessively powerful vacuum source implies disadvantages in terms of weight, cost, noise, and size.

[0009] Each brake is successively fluidly connected to the vacuum source according to a given sequence (fixed or evolving). The cycle may provide for more than one brake to be fluidly connected to the source at any given instant (n > 1 at any instant, for example). For instance, the two front brakes of a vehicle may simultaneously draw suction, then the two rear brakes. In a variant where N = 4 and where n oscillates between 1 and 2, one front brake draws suction, then the two rear brakes, then the other front brake.

[0010] The "source of depression" is fluidly connected "to a brake" is to be understood as an abuse of language meaning that a flow of depression can be created between the collection elements of this brake (groove in a lining, suction nozzle, etc.) and the source of depression.

[0011] While this document focuses on the successive suction of several brakes, the same approach can also be considered at the scale of a given brake, i.e., alternating suction on one lining and then another (or one nozzle and then another), or at the scale of a lining, i.e., successive suction on one suction element (groove) and then another suction element of the same lining. These different scales can be superimposed: for example, in a given cycle, the vacuum can be directed to a given brake for a given period, which can be subdivided into sub-stages where the suction alternates between the different different trims, each sub-step itself divided into sub-steps for suction in each of the grooves of the same trim.

[0012] 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.

[0013] In this document, the term "connection" or the fact that two elements are "connected" has been chosen to describe a physical link between two elements (most often by a pneumatic line). A "fluidic link" or the fact that two elements are "fluidically connected" means that a flow of suction air is made possible between these elements (most often by opening a valve on the physical connection between the two elements).

[0014] According to another aspect, the pneumatic circuit comprises N branches respectively connected to each of the N brakes, each branch housing a filter. The small-capacity filters usually fitted in these systems can be used. This design therefore takes advantage of elements already in place on a given brake and thus allows for retrofitting the new solution onto existing systems.

[0015] In one embodiment, the pneumatic circuit comprises N branches, each connected to one of the N brakes, and 1 branch connected to the vacuum source and housing a single filter. This arrangement requires a larger capacity filter but simplifies maintenance operations since only one filter needs to be replaced. Furthermore, the air velocity through the filter media can be reduced, thus lowering the pressure drop across the filter. Compared to using N filters, using a single, larger filter also allows for greater dust storage before clogging, the use of a media with higher filtration efficiency, and the overall use of a smaller filter media surface area.

[0016] Compared to a situation with one turbine and one filter per brake, the arrangement of a single turbine and a single filter reduces the required aerodynamic power for the turbine: indeed, if the pressure losses are 50 mbar at the linings, 10 mbar in the ducts connecting the linings to the filter, and 30 mbar in the filter, the total pressure losses are 90 mbar per brake. If the flow rate is divided by N, the pressure losses in the filter are divided by N². Thus, when N=4, the pressure losses in the filter (a single filter replacing 4 filters) are reduced from 30 mbar to 30 / 4²=1.9 mbar. The losses for a brake fall to less than 62 mbar, or 1.45 times less than the initial 90 mbar. For all 4 brakes, this amounts to a required aerodynamic power 5.8 times less (1.45x4).

[0017] According to another aspect, the N branches respectively connect each of the N brakes to a single valve, itself connected to the vacuum source, the valve being Capable, under the control of the control unit, of fluidly connecting the vacuum source to each of the N brakes according to the predefined cycle. This valve may have a single inlet connected to the vacuum source and at least N outlets, at least one of which may be connected to the inlet. The term "valve" is used here in a broad sense, as the valve may be composed of several elementary valves that together perform the function described above. The valve may be a solenoid spool valve. It is thus possible to control the suction in the manifold elements of each brake using a single physical component.

[0018] According to another aspect, each of the N branches accommodates a valve which is switchable, under the action of the control unit, between an open position, in which the respective brake is fluidly connected to the vacuum source, and a closed position, in which the respective brake is not fluidly connected to the vacuum source. In this arrangement, the N valves are simpler.

[0019] It is understood that hybrid designs, i.e., those situated between the single-valve solution and the N-valve solution, can be considered. Thus, several pneumatic branches in series can bring a vacuum to each of the brakes by means of an arrangement of appropriately controlled valves. For example, two or more brakes can be connected to a common valve (e.g., a solenoid spool valve), thereby reducing the number of actuators and pneumatic lines.

[0020] According to another aspect, N is between 4 and 10. Indeed, assuming that each brake is fluidly connected to the vacuum source for a duration 1 / N of the cycle time, the suction efficiency decreases (as shown later) when the suction time is less than 1 / 10th of the cycle time. It is therefore advantageous to use a single vacuum source for at most 10 brakes.

[0021] According to another aspect, in which the control unit is configured to fluidly connect the source of depression to each of the N brakes alternately, n(t) being equal to 1 at any time.

[0022] According to another aspect, in which n is 1 or 2 at each instant, n(t) alternately takes the values ​​1 or 2 during the cycle, the control unit being configured so that at a given instant, the source of depression is fluidly connected to a pair of brakes on the same axle or to a single brake.

[0023] According to another aspect, each brake comprises a pair of linings, and the particle collection element includes a groove arranged in each of the linings. The groove may be located near the trailing edge of the lining. Alternatively, the groove may be a peripheral groove surrounding the entire lining. The groove may be oblique and / or provided with a suction orifice, so that the suction airflow is at least partially in the opposite direction to the movement of the disc.

[0024] According to another aspect, each brake comprises a pair of linings and the particle collection element comprises a groove arranged in a nozzle disposed at a distance from the linings.

[0025] According to another aspect, each brake comprises 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; the collection element comprising two suction 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.

[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] Each 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 opposite 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 equipped 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 disk "sees" during its rotation, can be at a distance from the disk, while the downstream edge, equipped with the seal, is in contact with the disk. This seal allows for the scraping of any particles to improve still their aspiration.

[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, each 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 single nozzle can have the same characteristics described 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 to the disc, the angle of separation from the linings, or the attachment by means of 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, each brake comprises a disc 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] It is understood that in the preceding examples, the properties discussed for "each brake" may apply only to one or some of the brakes.

[0042] The invention also relates to a method of implementing the assembly such that described previously, the process comprises a succession of cycles each comprising a succession of suction stages, each during which exactly a number n(t) of N brakes is fluidly connected to the source of depression, where for any t, n(t) is an integer between 0 and Nl.

[0043] According to another aspect, in a given cycle, each of the N brakes is connected exactly once to the vacuum source. In a variant, some of the N brakes (for example, the most powerful ones, often at the front of vehicles) may be subjected to suction several times per cycle.

[0044] According to another aspect, each of the suction stages extends over the same duration. In one embodiment, some of the N brakes (for example, the most powerful ones, often at the front of vehicles) may undergo suction for a longer period than the less powerful brakes, which produce fewer particles.

[0045] According to another aspect, on a cycle, the duration T(t) of each suction step is proportional to the number n(t) of brakes connected to the source of depression during said step.

[0046] According to another aspect, the fluidic linkage cycles of the N brakes at the source of depression take place independently of brake activation.

[0047] According to another aspect, each cycle includes a waiting stage during which none of the N brakes is fluidly connected to the vacuum source, and / or during which the vacuum source is inactive. At any time t during this stage, n(t) is therefore zero. This control strategy optimizes power consumption to avoid unnecessarily creating suction. In a variant, several waiting stages can be provided, for example, evenly distributed during each cycle.

[0048] The invention also relates to a method of implementing the assembly as described above, the method comprising switching the vacuum source from an inactive state to an active state while it is not fluidly connected to any of the N brakes, and then fluidly connecting the vacuum source to one of the N brakes. This makes it possible to clean the lines of any particles that might be deposited there by creating a water hammer effect or a vacuum wave that will propagate when the brake(s) are depressurized. Before fluidly connecting the brake(s) to the vacuum source, it may be advantageous to allow a few seconds to elapse to enable the vacuum source to reach a nominal (e.g., maximum) vacuum.

[0049] In addition to the benefits of ease of assembly, maintenance, and control, the use of a single vacuum source alternately connected to each brake offers new possibilities: indeed, compared to a system with a turbine that draws particles from two brakes (simultaneously), and where each brake does not By utilizing only half of the turbine's nominal suction, the solution presented here allows each brake to access the full power of a turbine. It is therefore possible to mount brake pads with larger collection elements (wider groove, larger bore). It is also possible to use smaller diameter hoses, which are easier to integrate into a vehicle (because they are more flexible and less bulky). Brief description of the drawings

[0050] Other features, details and advantages will become apparent upon reading the detailed description below, and upon analysis of the accompanying drawings, on which:

[0051] [Fig-1] shows a vehicle, a disc brake and an assembly with a system of particle capture.

[0052] [Fig.2] shows an assembly with a particle capture system.

[0053] [Fig.3] illustrates three examples of brake pads.

[0054] [Fig.4A] shows a chronogram of a first process.

[0055] [Fig.4B] represents a flowchart of the process of [Fig.4A].

[0056] [Fig.5A] illustrates a chronogram of a second process.

[0057] [Fig.5B] shows a flowchart of the process of [Fig.4A].

[0058] [Fig.6] represents a flowchart of a third process.

[0059] [Fig.7] illustrates an isometric view of a disc brake.

[0060] [Fig.8] represents an isometric view of a suction nozzle.

[0061] [Fig.9] shows a cross-sectional view of the suction nozzles mounted around the disc.

[0062] [Fig. 10] schematically illustrates a front view of the positioning of the nozzles.

[0063] [Fig. 11] represents a design variant for a nozzle.

[0064] [Fig. 12] shows a design variant for a nozzle.

[0065] [Fig. 13] illustrates an example of a single nozzle accommodating two grooves. Description of the implementation methods

[0066] 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 all technically possible combinations.

[0067] The figures and their descriptions focus on the situation where the suction alternates from one brake to another (n=l or possibly n=0 during the waiting phases). The reader will be able to extrapolate situations where n takes other values ​​during a cycle.

[0068] Figure 1 illustrates a vehicle 1, road (car, van, truck, etc.) or rail (train, tram, metro, etc.), comprising at least two braking devices 2 of the disc brake type. The vehicle 1 comprises at least one braking assembly 100. The first brake 2 is labeled (1), the second is labeled (2). Figure 1 represents In short, the fact that there can be a number N of brakes, the Nth being denoted (N) on [Fig.1]. N can be between 2 and 40, preferably between 2 and 10, more preferably N is 4, 6, 8 or 10.

[0069] Each 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 may 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 faces respective of disc 4.

[0070] 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.

[0071] A particle capture system 20 is thus provided to recover the particles produced by the brakes 2.

[0072] The collection system 20 comprises a single source of depression 22, here represented as a turbine.

[0073] The vacuum source 22 is connected by a pneumatic circuit to each brake. The pneumatic circuit may comprise N branches 24 on which a respective filter 26 is arranged.

[0074] 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 may include memory, a processor, and communication buses. It may take the form of hardware and / or software components dedicated to controlling the sensor system or be integrated into one of the vehicle's main controllers (CAN, ECU, EMS, etc.).

[0075] The pneumatic circuit may include, in addition to the branches 24 and the filters 26, branches 32, 34 which connect the branches 24 to the vacuum source 22. Valves 36 may be provided on the branches 24, the state of which (open or closed) can be controlled by the control unit 30 via a connection 38. The valves 36 are controlled according to one of the methods described below, in order to carry out the suction cycles in which a certain number n(t) of branches 24 (n between 0 and Nl) are fluidly connected to the vacuum source 22 at a given time. If the [Fig.1] shows several nodes between branches 24 and branch 34; in one variant, all branches 24 join at a single node which meets branch 34, unique, leading to the depression source 22. A hybrid variant with groups of branches 24 joining at a valve 36 is also conceivable.

[0076] The branches 24 are connected to the collection elements (44, 54, 64 on the [Fig.3]), i.e. to the trim elements 10, 12 in the vicinity of the interface between the trims 10, 12 and the disc 4.

[0077] The valves 36 are shown schematically. They can be solenoid valves, for example spool valves. In this example, they can be 2 / 2 valves (2 positions, 2 ports).

[0078] 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 34. No suction of particles is possible. In this case, the vacuum source is 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 possible. In this case, the vacuum source is said to be in an active state, regardless of its (non-zero) speed and / or the (non-zero) amplitude of the electrical current supplied to the motor.

[0079] The pneumatic circuit structure shown in [Fig.1] is adaptable to existing systems, for which each brake already has a filter.

[0080] Figure 2 shows a variant for the pneumatic circuit. In this example, a single filter 26 is provided on the line 34 and a single valve 36 selects the brake(s) 2 which are fluidly connected to the turbine 22. Each of the N lines 24 is directly connected to the valve 36, which is itself controlled by the control unit 30 via the connection 38. This design has advantages in terms of the number of components and simplification of control.

[0081] Figures 1 and 2 show two examples of pneumatic circuit structures. Other variants that do not require further explanation are also conceivable, for example with a single filter 26 on branch 34 (as in [Fig. 2]) and N valves on branches 24 (as in [Fig. 1]), or conversely with N filters (as in [Fig. 1]) and a single valve 36 (as in [Fig. 2]). Finally, those skilled in the art will understand that other structures are possible, with any combination of filters and valves, each numbering from 1 to N.

[0082] Figure 3 shows three examples of brake pads 40, 50, 60 that can be used with the particle capture system. Other variants are also conceivable.

[0083] The plate 40 includes a base 42 to which the trim 10 is fixed. In In the trim 10, a particle collection groove 44 is formed. This groove is connected to suction means.

[0084] 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.

[0085] 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.

[0086] Thus, various collection elements 44, 54, 64 can be provided on a plate for the aspiration of particles.

[0087] Figure 4A shows a timing diagram illustrating the alternating suction on each of the brakes (n(t) = 1 for all t). In this figure, four time lines are shown for each of the four brakes, i.e., when N equals 4. The reader can easily extrapolate the operation when N takes other values.

[0088] The horizontal axis is the time axis. Each axis corresponds to one of the brakes. The notches represent the fluidic connection of the given brake to the source of depression.

[0089] At time t0, the first brake (1) is connected to the vacuum source until time t1. At time t1, the fluid connection of the first brake (1) to the vacuum source is interrupted, and simultaneously the second brake (2) is connected to the vacuum source. At time t2, the fluid connection of the second brake (2) to the vacuum source is interrupted, and simultaneously the third brake (3) is connected to the vacuum source. At time t3, the fluid connection of the third brake (3) to the vacuum source is interrupted, and simultaneously the fourth brake (4) is connected to the vacuum source. At time t4, the fluid connection of the fourth brake (4) to the vacuum source is interrupted, and simultaneously the first brake (1) is connected to the vacuum source. All these steps describe a cycle C, which is repeated continuously.

[0090] The durations between t0 and t1, between t1 and t2, between t2 and t3, and between t3 and t4 can all be equal to a duration denoted T. Thus, in this example, all the fluidic link phases of each of the brakes have the same duration T.

[0091] The suction duration T for each brake can be between 5 seconds and 2 minutes, preferably between 10 seconds and 1 minute.

[0092] Other configurations are naturally possible. For example, the suction time of two of the four brakes (the largest ones) can be longer, for example by 20% or 30% compared to the suction time of the other two brakes.

[0093] The most powerful brakes may, for example, be two brakes joined together in the cycle (e.g., (1) and (2)). Thus, the cycle comprises two long phases followed by two short phases. Alternatively, the most powerful brakes may be spaced apart in the cycle (e.g., brakes (1) and (3)). The cycle then comprises a alternation between long and short phases. In one variant, several suction phases for the same brake can be reproduced during the same cycle.

[0094] Also, in a variant where n(t) varies, the stages during which more brakes are drawn can last longer than the stages where fewer brakes are connected to the vacuum source. Thus, the duration of a stage becomes a variable T(t) that can be proportional to n(t).

[0095] Figure 4B shows a flowchart illustrating a process 1000 related to Figure 4A, generalized to N brakes. The process 1000 comprises a step 1100.1 of fluidic connection of the first brake to the vacuum source, followed by a step 1100.2 of fluidic connection of the second brake to the vacuum source, followed by as many similar steps for the other brakes up to step 1100.N. At any given time, only one brake is fluidically connected to the vacuum source. After step 1100.N, the cycle restarts at step 1100.1.

[0096] Figure 5A shows a method in which the start of suction on one brake is not always simultaneous with the cessation of suction on another brake. In the illustrated example, a waiting step 2200 begins at time t4 (when suction on the fourth brake ceases). The first brake does not resume suction until time t5. During this waiting step, no brake is fluidly connected to the vacuum source and / or the vacuum source is inactive. It is understood that several waiting steps, distributed throughout the cycle, can be provided. For example, each cessation of suction on a brake can be followed by a waiting step before suction on another brake begins. Thus, the cycle consists of suction steps where n(t) = 1 and waiting steps where n(t) = 0.

[0097] If we denote T the duration of each fluidic binding phase, or the average duration of these phases when they are not of identical durations, the waiting stage has a duration T' which can be greater or less than T. For example T' can be double or triple T. In a variant, T'=N*T.

[0098] It is understood that, in the same way as described in relation to [Fig.4A], some brakes may draw longer than others, or several times during a cycle.

[0099] Figure 5B shows a flowchart illustrating a process 2000 related to Figure 5A, generalized to N brakes. The process 2000 comprises a step 2100.1 of fluidic connection of the first brake to the vacuum source, followed by a step 2100.2 of fluidic connection of the second brake to the vacuum source, followed by as many similar steps for the other brakes up to step 2100.N. At any given time, only one brake is fluidically connected to the vacuum source (since n(t) = 1 during these steps). After step 2100.N, the cycle continues with a waiting step 2200 (n(t) = 0 during this step). After the waiting step 2200, the cycle restarts at step 2100.1. As As mentioned above, a waiting step can also be provided between a step 2100.x and a step 2100.X+1 (x integer from 1 to N).

[0100] Whether in process 1000 or 2000 (Figures 4 or 5), the duration during which a given brake is not in the suction phase can be between 30 seconds and 30 minutes, preferably between 4 and 10 minutes. Advantageously, the ratio, for each brake, between the suction time and the non-suction time can be between 1 / 3 and 1 / 10.

[0101] Figure 6 illustrates a method 3000 for using the assembly described in Figures 1 or 2. Method 3000 consists of blocking all fluid connections to the brakes, creating a vacuum, and then opening one or more connections to the brakes. Thus, step 3100 consists of closing the valve(s) of the pneumatic circuit. Step 3200 consists of activating or maintaining the vacuum source, for example, until a desired vacuum is reached. Step 3300 consists of opening one or more of the valves of the pneumatic circuit, thereby creating a water hammer or suction wave that propagates through the pneumatic circuit to dislodge the particles adhering to the internal walls of the pneumatic lines and the collection groove. Method 3000 can be repeated for each brake, one after the other, or for any combination of brakes, until all the lines are cleaned.

[0102] In the examples shown in the preceding figures, it is implied that the valves are controlled by the control unit to be opened or closed, or to operate a given fluidic connection between the source of vacuum and a given brake.

[0103] The reasons which allow effective particle capture despite intermittent aspiration are explained below.

[0104] 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

[0105] It is observed that the mere fact that a lining has a collection groove halves the amount of particles escaping into the environment. This 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 act as a reservoir is lost.

[0106] The above tests were carried out with a groove arranged in a downstream part of the brake lining, i.e., the part of the lining seen last 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.

[0107] 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.

[0108] 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 brake of the vehicle): 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

[0109] It appears that cyclic suction is as effective as suction limited to braking sequences. Approximately 67% of the PM10 particles produced are captured. Cyclic suction allows the use of one turbine for multiple braking sequences.

[0110] 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 (T1=1 min; T2=3 min) Cyclic suction (T1=1 min; T2=6 min) Cyclic suction (T1=1 min; T2=13 min) Cyclic suction (T1=1 min; T2=27 min) 1.8 2.2 2.6 3.6 3.7 Table 3

[0111] Tests with different values ​​of T1 and T2 show that when the ratio T1 / T2 If the efficiency is less than 10%, the quantity of particles detected (produced but not captured) is approximately 3.7 mg / km / brake, which is the quantity detected in the absence of suction. Therefore, depending on the chosen efficiency threshold (for example, a threshold of 67%), using a single suction turbine for more than 10 brakes is not advisable because the suction time per brake becomes insufficient compared to the non-suction time. For lower chosen (or regulatory) efficiency thresholds, it is possible to use only one turbine for more than 10 brakes.

[0112] The invention has been illustrated using a disc brake, but it is also applicable to other types of friction brakes, comprising a rotor and (at least) one friction lining. Thus, the invention may also relate to a vehicle assembly comprising: N rotor brakes (disc, drum, or other), where N is an integer greater than or equal to two, each of the N brakes being equipped with at least one friction lining intended to rub against the rotor during a braking phase, each lining having a particle collection element; and a brake particle collection system comprising: a single vacuum source; a pneumatic circuit extending from the vacuum source to the collection elements of the linings of each of the N brakes; and a control unit configured to fluidly connect the vacuum source to each of the N brakes alternately.

[0113] Figures 7 to 13 show means of collecting particles which can be an alternative to grooves 44, 54, 64, or complementary to them.

[0114] Figure 7 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.

[0115] In this example, the caliper 8 is floating, that is to say, it is free to slide relative to a bracket 9 fixed to the wheel hub. The invention is obviously adaptable to a fixed caliper brake.

[0116] 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.

[0117] A fixing bracket 150 allows the rigid pipes 148, 149 to be fixed to the clevis 9. The rigid pipes 148, 149 pass through two holes 152 in the bracket 150, with a tight fit. A third hole allows the bracket 150 to be fixed to the clevis 9. The bracket 150 may be V-shaped. In one embodiment, the bracket is formed in the clevis 9. The pipes 148, 149 protrude from the bracket 150. They may be connected to the depression source 22 by means of flexible hoses (not shown).

[0118] The conduit 148 may have a U-shaped form and the conduit 149 may be straight.

[0119] Figure 8 shows an isometric view of a nozzle 140. The nozzle includes an edge upstream edge 141 (i.e., the one seen by a point on the disk first) and a downstream edge 142 (seen last). The downstream edge 142 may be fitted with a seal (for example, a brush or elastomer seal) which scrapes against the disk 4. In one variant, or in combination, the downstream edge 142 may be further from the disk than the upstream edge, for example, by a distance at least 50% greater.

[0120] 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.

[0121] 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. 8]) 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.

[0122] The nozzle 140 may 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.

[0123] The conduit 148, 149 creates a suction in the groove 146. A suction orifice 147 is provided for this purpose in the nozzle 140.

[0124] Figure 9 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.

[0125] Pipe 148 forms a U and pipe 149 is straight. In this example, the conduits 148, 149 are coplanar but other designs are conceivable.

[0126] In the examples in Figures 7 to 9, 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.

[0127] Figure 10 schematically shows the positioning of the nozzles 140. The fittings 10 and 12 can define a median radius R0, and the longitudinal axis A of the 140 nozzles can be aligned with a radius R, angularly offset from radius R0 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.

[0128] Figures 11 and 12 illustrate two design variants of nozzle 140.

[0129] On [Fig. 11], 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.

[0130] Figure 12 shows a pair of nozzles 140 with two leakage orifices 143 at both radial ends of groove 146. Air is drawn in both from the side of the disc and at the orifices 143, forcing an airflow into the groove that is parallel to the friction surfaces of the disc.

[0131] Fig. 13 shows an example in which a single nozzle 140 receives both grooves 146. This nozzle can have a general U-shape. Suction can be achieved through a single conduit 48, located in the plane of the disc. A narrower auxiliary groove 160 can 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.

Claims

Demands

1. Assembly (100) for vehicle (1) comprising: - N disc brakes (2), where N is an integer greater than or equal to two, each of the N disc brakes (2) being equipped with a particle collection element (44, 54, 64, 146); and - a brake particle collection system (20) comprising: • a single vacuum source (22); • a pneumatic circuit (24, 26, 32, 34, 36, 38, 148, 149) extending from the vacuum source (22) to the collection elements (44, 54, 64, 146) of each of the N brakes (2); and • a control unit (30) configured to fluidly connect the vacuum source (22) to each of the N brakes (2) successively according to a predefined cycle (C), such that at any given time t, only n(t) brakes are fluidly connected to the vacuum source (22), where for any t, n(t) is an integer between 0 and Nl.

2. Assembly (100) according to claim 1, wherein the pneumatic circuit (24, 26, 32, 34, 36, 38) comprises N branches (24) respectively connected to each of the N brakes (2), each of the branches (24) housing a filter (26).

3. Assembly (100) according to claim 1, wherein the pneumatic circuit comprises N branches (24) respectively connected to each of the N brakes (2), and 1 branch (34) connected to the vacuum source (22) and housing a single filter (26).

4. Assembly (100) according to any one of claims 2 or 3, wherein the N branches (24) respectively connect each of the N brakes (2) to a single valve (36), itself connected to the vacuum source (22), the valve (36) being able, under the action of the control unit (30), to fluidly connect the vacuum source (22) to each of the N brakes (2) according to the predefined cycle (C).

5. Assembly (100) according to any one of claims 2 or 3, wherein each of the N branches (24) accommodates a valve (36) which is switchable, under the action of the control unit (30), between an open position, in which the respective brake (2) is fluidly connected to the source of depression (22), and a closed position, in which the respective brake (2) is not fluidly connected to the source of depression (22).

6. Set (100) according to any one of claims 1 to 5, in which N is between 4 and 10.

7. Assembly (100) according to any one of claims 1 to 6, wherein the control unit (30) is configured to fluidly connect the vacuum source (22) to each of the N brakes (2) alternately, n(t) being equal to 1 at any time.

8. Assembly according to any one of claims 1 to 6, wherein n(t) alternately takes the values ​​1 or 2 during the cycle (C), the control unit (30) being configured so that at a given instant, the source of depression (22) is fluidly connected to a pair of brakes of the same axle or to a single brake.

9. Assembly (100) according to any one of claims 1 to 8, wherein each brake (2) comprises a pair of linings (10, 12) and the particle collection element comprises a groove (44, 54, 64) arranged in each of the linings (10, 12).

10. Assembly (100) according to any one of claims 1 to 9, wherein each brake (2) comprises a pair of linings (10, 12) and the particle collection element comprises a groove (146) arranged in a nozzle (140) disposed at a distance from the linings (10, 12).

11. Assembly (100) according to claim 10, wherein each brake (2) comprises 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), the collection element 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 (Cl) to the outer circle (C2).

12. Assembly (100) according to claim 11, 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.

13. Set (100) according to any one of claims 11 or 12, in which each groove (146) is arranged in a respective nozzle (140).

14. Assembly (100) according to claim 13, wherein each nozzle (140) has at least one leakage orifice (143) in fluidic connection with the groove (146).

15. Assembly (100) according to any one of claims 13 or 14, 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).

16. Assembly (100) according to any one of claims 13 to 15, 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.

17. Assembly (100) according to any one of claims 13 to 16, 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).

18. Assembly (100) according to any one of claims 13 to 17, 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 seals (10, 12), by an angle (a) between 20° and 60°

19. Uv . Assembly (100) according to any one of claims 13 to 18, wherein each 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).

20. Assembly (100) according to any one of claims 13 to 19, 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).

21. Assembly (100) according to claims 19 and 20, wherein a fixing bracket (150) connects the rigid pipes (148, 149) to the stirrup or clevis (9), the fixing bracket (150) comprising two orifices (152) through which the rigid pipes (148, 149) pass.

22. Assembly (100) according to any one of claims 11 or 12, wherein the two grooves (146) are arranged in a single nozzle (140).

23. Assembly (100) according to claim 22, wherein an auxiliary groove (160) that overlaps the side of the disc connects together the two suction grooves (146).

24. Assembly (100) according to any one of claims 1 to 23, wherein each brake comprises a disc (4) covered with a ceramic coating.

25. Method (1000, 2000) of implementing the assembly according to any one of claims 1 to 24, the method comprising a succession of cycles (C) each comprising a succession of suction steps (1100.1, 1100.2, ... 1100.N, 2100.1, 2100.2, ... 2100.N), each during which exactly a number n(t) of N brakes (2) is fluidly connected to the vacuum source (22), where for any t, n(t) is an integer between 0 and Nl.

26. Method according to claim 25, wherein in a given cycle (C), each of the N brakes (2) is connected exactly once to the source of depression (22).

27. ​​A method according to any one of claims 25 or 26, wherein each of the aspiration steps (1100.1, 1100.2, ... 1100.N, 2100.1, 2100.2, ... 2100.N) extends over the same duration (T).

28. A method according to any one of claims 25 to 27, wherein on a cycle, the duration (T(t)) of each suction step (1100.1, 1100.2, ... 1100.N, 2100.1, 2100.2, ... 2100.N) is proportional to the number n(t) of brakes connected to the vacuum source during said step.

29. A method according to any one of claims 25 to 28, wherein the fluidic linkage cycles (C) of the N brakes (2) to the vacuum source (22) take place independently of the activation of the brake (2).

30. A method according to any one of claims 25 to 29, wherein each cycle (C) includes a waiting step (2200) during which none of the N brakes (2) is fluidly connected to the vacuum source (22), and / or during which the vacuum source (22) is inactive.

31. Method (3000) of implementing the assembly according to any one of claims 1 to 24, comprising switching the vacuum source from an inactive state to an active state while it is not fluidically connected to any of the N brakes, then fluidically connecting (3300) the vacuum source (22) to one of the N brakes (2).

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