Cooling system for a brake disk and method for operating such a system

Abstract

The invention relates to a cooling system (1) for the controlled cooling of a braking system (3), in particular of a brake disk (31) of a motor vehicle, the system comprising a duct (6) for an air flow, and a deflector (10), the duct (6) comprising an inlet opening (7) and an outlet opening (8), the deflector (10) being arranged downstream of the inlet opening (8) of the duct (6) following on from one face of the duct (6), the deflector (10) being movable between an unfolded position in which it forms an extension of the duct (6), the unfolded position increasing the incoming air flow, and a folded position in which it is folded back inside the duct (6).

Description

[0001] TITLE: System for cooling a brake disc and method of operating such a system

[0002] The invention relates to a system for the controlled cooling of a brake disc. The invention also relates to a vehicle, in particular a motor vehicle, comprising such a system. The invention also relates to a method of operating such a system or such a vehicle.

[0003] In a motor vehicle equipped with a disc brake-based braking system, it is important to be able to cool such a brake disc. The brake discs of motor vehicles are likely to heat up considerably under certain operating conditions, particularly during strong decelerations, for example, or in the event of successive medium braking. An excessively high temperature of the brake disc can cause a malfunction of the vehicle's braking system, resulting in an increase in the stopping distance and a reduction in the lifespan of the brake components, for example premature wear of the disc and brake pads, which can lead in particular to the emission of particles resulting from the degradation following heating. It is therefore necessary to reduce this heating temperature of the braking device.

[0004] Motor vehicles are known which include air intakes at the front of the vehicle or on the sides of the vehicle to cool the brake discs.

[0005] However, these solutions have drawbacks from an aerodynamic point of view since they increase the value of the aerodynamic drag coefficient Cx and are not always effective, in particular when the brakes are heavily stressed and are likely to cause heating, for example during strong deceleration. The aim of the invention is to provide a system for the controlled cooling of a brake disc and a method for operating such a system which overcomes the above drawbacks and improves the devices and methods known from the prior art. In particular, the invention makes it possible to produce a system and a method which are simple and which have a reduced cost and which make it possible to optimize the compromise between a high brake cooling capacity and reduced aerodynamic drag.

[0006] The aim is achieved by means of a system for the controlled cooling of a braking system, in particular of a brake disc of a motor vehicle, comprising a duct intended for an air flow, and a deflector, the duct comprising an inlet opening and an outlet opening, the deflector being arranged downstream of the inlet opening of the duct along one face of the duct, the deflector being movable between a position deployed outwards in the extension of the duct, said deployed position being such as to increase the incoming air flow, and a retracted position, in which it is folded inside the duct.

[0007] The invention advantageously makes it possible to optimize the compromise between the aerodynamic performance of the vehicle, with in particular a limiting action on the drag of the wheel by its placement upstream of the wheel, thus making it possible to deflect the air striking the wheel, and a high cooling capacity of the braking system or brakes, in particular the brake discs of the vehicle.

[0008] In preferred embodiments of the invention, one and / or the other of the following features are further used, taken alone or in combination:

[0009] - The movement of the deflector from the retracted position to the deployed position and from the deployed position to the retracted position is carried out by translation - The translation of the deflector is carried out in a substantially vertical direction.

[0010] - The main direction of the duct has an angle of inclination of between 30° and 60° relative to a longitudinal direction of movement of the vehicle and the translation of the deflector is carried out in the extension of the duct following the main direction of the duct.

[0011] - The deflector extends transversely across the entire width of the duct.

[0012] - The system includes a motor allowing the translational movement of the deflector.

[0013] - The outlet opening of the conduit has a smaller surface area than the inlet opening of the conduit and the outlet opening of the conduit has a rectangular or substantially rectangular shape.

[0014] - The conduit includes a tubular section made of flexible material.

[0015] The invention also relates to a motor vehicle comprising a system according to one of the preceding characteristics, the inlet opening of the conduit being located at a location on an underbody of the vehicle, upstream of a wheel, the outlet opening of the conduit being located at a location opposite a brake disc linked to said wheel, the conduit being partly secured to the passage screen of said wheel.

[0016] The invention also relates to a method of operating a previously defined system or of operating a previously defined vehicle, comprising:

[0017] A step of comparing the vehicle speed with a threshold value; and

[0018] - if the vehicle speed is greater than or equal to the threshold value, placing the system in a combined braking and aerodynamic performance mode in which the deflector is in the deployed position; The method may also additionally comprise, in the case of a deployed deflector:

[0019] - a step of comparing the temperature of the braking system with a threshold value; and if the temperature of the braking system is higher than the threshold value, putting the system into a braking performance mode in which the deflector is in the retracted position.

[0020] The attached drawings represent, by way of example, an embodiment of a system according to the invention and an embodiment of an operating method according to the invention.

[0021] [Fig. 1] Figure 1 schematically represents an embodiment of a system for the controlled cooling of a brake disc of a vehicle, the deflector being in the folded or closed position.

[0022] [Fig. 2] Figure 2 schematically represents an embodiment of a system for the controlled cooling of a brake disc of a vehicle, the deflector being in the deployed or open position.

[0023] [Fig. 3] Figure 3 is a front view schematically showing one embodiment of a system for the controlled cooling of a vehicle brake disc, the deflector being in the deployed or open position.

[0024] In the context of the present application, the terms "front", "rear", "left", "right", "lower", "upper", are understood in reference to an orthonormal XYZ reference frame of motor vehicles, in which the X axis designates the longitudinal direction in which the vehicle usually travels in a straight line, and is oriented from the front to the rear of the vehicle, or from upstream to downstream. The Y axis designates the transverse direction of the vehicle and is oriented from the left side to the right side of the vehicle. The Z axis designates the vertical direction, and is oriented from the bottom to the top, from the lower part to the upper part of the vehicle. Furthermore, in the different figures, the same references designate identical or similar elements.

[0025] Figures 1 and 2 show an embodiment of a system 1 for the controlled cooling of a braking system 3, in particular of a brake disc 31, in particular of a motor vehicle 100. The vehicle 100 comprises at least one wheel 2 and at least one braking system 3 associated with the wheel 2.

[0026] The system 1 comprises a conduit 6, in particular of substantially tubular shape and connected to the underbody 23 of the vehicle 100. The conduit 6 is intended for a flow or circulation or passage of a fluid, in particular air.

[0027] The conduit 6 comprises an inlet opening 7 and an outlet opening 8.

[0028] The deflector 10 is arranged downstream of the inlet opening 8 of the duct 6, that is to say behind the inlet opening 7 of the duct 6 in the direction of movement of the vehicle, and along an internal wall, in particular an internal face of the duct 6. The deflector 10 is movable between a position deployed outwards in the extension of the duct 6, the deployed position being such as to increase the flow of air entering the interior of the duct, and a retracted position, in which it is folded inside the duct 6.

[0029] In detail in Figure 1 is shown the deflector in the retracted position, that is to say folded inside the duct. In this folded position, or folded position of the deflector 10, the deflector 10 is without interference with the incoming air flow. The folded position of the deflector 10 is the default position of the deflector 10.

[0030] The inlet opening 7 of the duct 6 has, in the embodiment shown in the figures, a semi-circular shape and the deflector 10 extends along the diameter w of the semi-circle, along the substantially vertical inner wall of the duct, bordering the diameter of the semi-circle. The opening has, for example, a dimension of approximately 50 to 100 mm along X.

[0031] The conduit 6 extends in particular in a main direction, or main direction of elongation A1. The conduit 6 comprises at least a first tubular section 61 extending in the main direction A1, from the inlet opening 7. The diameter d of the cross-section of the first tubular section 61 of the conduit 6 is for example between 50 mm and 100 mm.

[0032] As visible in figure 1, the main direction A1 of the conduit 6 forms an angle a called the inclination angle, with the longitudinal direction X.

[0033] Advantageously, the angle of inclination a between the main direction A1 of the conduit 6 and the longitudinal direction X, which is also the direction of the base, is between 30° and 60°.

[0034] The angle of inclination a may in particular be chosen as a function of the vehicle 100 and / or as a function of the dimensions of a wheel 2 of a vehicle. Advantageously, the conduit 6 is inclined so as to open out in the downstream direction relative to the vertical direction Z.

[0035] The movement of the deflector from the retracted position to the deployed position and from the deployed position to the retracted position is carried out by translation. This translation is carried out in a substantially vertical direction, in the extension of the conduit 6 along the main direction A1. The deflector 10 is capable of extending perpendicularly or substantially perpendicularly to the underbody 23 of the vehicle 100 in the deployed position.

[0036] Advantageously, a motorization allows the translational movement of the deflector 6.

[0037] In detail, the system 1 may comprise an actuator connected to the deflector 10. The actuator may be active. The actuator may be controlled by a computer, in particular by a computer of a vehicle 100. The actuator may in particular be controlled, in particular actively, as a function of the speed of the vehicle 100.

[0038] In an embodiment illustrated in Figure 1, the deflector 10 extends transversely over the entire width w of the duct 6, which makes it possible to maximize the air flow inside the duct, for a deployment dimension of the deflector. Several deployment heights h1 and h2 can be envisaged. A greater deployment height of the deflector h2 greater than h1 makes it possible to send more air flow inside the duct.

[0039] As seen in Figure 2, in the deployed position or open position of the deflector 10, the deflector 10 interferes with the inlet direction or main direction A1 of the duct 6, which makes it possible to increase the flow of air entering the interior of the duct.

[0040] Advantageously, the outlet opening 8 of the conduit 6 has a surface area smaller than the surface area of ​​the inlet opening 7 of the conduit 6 and the outlet opening 8 of the conduit 6 has, for example, a rectangular or substantially rectangular shape. Preferably, the shape of the conduit 6 at the location of the outlet opening 8 is different from the shape of the conduit 6 upstream of the outlet opening 8. The shape of the conduit 6 at the location of the outlet opening 8 may in particular be chosen so that the conduit 6 does not come into abutment against one or more elements of a wheel 2 or against one or more elements associated with a wheel 2 of a vehicle 100.

[0041] The shape of the duct allows for better focusing of the air flow at the outlet of duct 6.

[0042] The surface area of ​​the outlet opening 8 of the conduit 6 is, for example, of the order of 15% to 30% smaller than the surface area of ​​the inlet opening 7 of the conduit 6. As an example of the order of magnitude of dimensions, the surface area of ​​the inlet opening 7 of the conduit 6 is, for example, of the order of 10,000 mm 2 , and the surface area of ​​the outlet opening 8 of the conduit 6 is for example of the order of 8000 mm 2 .

[0043] Advantageously, the duct 6 may comprise an elbow 9. The elbow 9 is intended to optimize the orientation of the air flow exiting the duct 6, in particular so that the air flow exiting the duct 6 reaches the region of a brake disc 31 most favorable for cooling the brake disc. In detail, it makes it possible to optimize the direction and / or the position of an air flow exiting the duct 6.

[0044] Furthermore, in order not to hinder the wheel movement, this air conveyance duct is entirely outside the wheel casing, passing for example around the shock absorber to return as close as possible to the brake disc. The duct 6 can thus comprise portions partially secured to the passage screen of said wheel.

[0045] In addition, the conduit may have a flexible part 62, that is to say a tubular section made of flexible material allowing the conduit to follow the movements of the ground connection, because the wheel being mobile, it is likely to bounce causing a relative movement between the outlet and the inlet of the system.

[0046] The conduit 6 thus comprises, for example, a first tubular section 61 extending in particular in the main direction A1 and a second tubular section 63, extending in a main direction, or main direction of elongation, A2.

[0047] The first tubular section 61 extends in particular from the inlet opening 7 of the conduit 6 to the elbow 9, the second section 63 extends for example in particular from the elbow 9 to the outlet opening 8. The length L1 of the first tubular section 61, that is to say its dimension along the main direction A1, is for example between 100 mm and 200 mm, for example of the order of 150 mm.

[0048] The modification of the main direction of the duct 6 for the second section 63 compared to the first section 61, or in other words the fact that the duct 6 comprises an elbow 9, makes it possible in particular to optimize the flow of fluid on the system and therefore to optimize the ventilation of a braking system 3, in particular a brake disc 31, by air leaving the duct 6 further downstream compared to the case where the duct 6 would extend in the main direction A1 over its entire length.

[0049] The length L2 of the second tubular section 63, that is to say its dimension along the main direction A2, is for example between 50 mm and 150 mm, for example of the order of 100 mm.

[0050] The shape of the duct 6 at the outlet or at its downstream end and / or the bend 9 of the duct 6 also make it possible in particular to avoid the constraints linked to a rim of a wheel 2, in particular in terms of size. Thus, the duct 6 can be configured so that an air flow leaving the duct 6 reaches a brake disc 31 and ventilates it, without the duct 6 being in contact with the brake disc 31, which makes it possible to avoid damaging the brake disc 31, in particular by avoiding the duct 6 creating possible impacts on the brake disc 31.

[0051] The braking system 3 is in particular a disc brake system. The braking system 3 comprises, for example, a brake disc 31 and a brake caliper comprising brake pads.

[0052] The outlet opening 8 of the conduit 6 may be located at a location opposite a brake disc 31. The main direction of the conduit 6 at the outlet of the conduit 6 is preferably offset relative to an axis of rotation of a wheel 2. A mode of execution of a method of operation of a system 1 of the type described above or of a vehicle 100 of the type described above is described below with reference to FIGS. 1, 2 and 3.

[0053] When the vehicle 100 is in operation, in particular when the vehicle 100 is moving forward, air flows in a flow direction D towards the vehicle 100. The flow direction D of the air flow is for example parallel or substantially parallel to the longitudinal direction X. The flow direction of the air flow is represented by an arrow 15 in FIGS. 1 and 2. The air flow represented is in particular a direct or frontal air flow. The direction of rotation of a wheel 2 of the vehicle 100 is represented by an arrow 25.

[0054] The duct 6 of the system 1 is inclined so as to open in a downstream direction relative to the air flow direction D.

[0055] Figures 1 and 2 schematically represent the system 1 in operation, when the deflector 10 is in the folded position for figure 1 and in the deployed position for figures 2 and 3.

[0056] In the retracted position of the deflector 10 shown in Figure 1, the deflector 10 is without interference with the inlet direction of the duct 6, it does not interfere with the main direction A1 of the duct 6. Air circulates or flows in the duct 6, the air flow flowing in the duct 6 coming from a direct air flow and / or a frontal flow and / or an air flow flowing under the vehicle.

[0057] The system 1 is for example controlled, in particular actively, by an actuator arranged in the underbody of the vehicle capable of moving the deflector 10 from the deployed position to the retracted position and vice versa, by means of a method for actively controlling the deflector 10. Such a method improves the cooling capacity of the brakes and the aerodynamic performance of the vehicle, in particular at high vehicle speeds, for example from 80 km / h. The deflector 10 is capable of being controlled according to the cooling requirement of a brake disc 31 of a vehicle 100 and / or the coupled requirement for aerodynamic and braking performance.

[0058] System 1 is, for example, capable of operating in two modes: a braking performance mode and a combined aerodynamic and braking performance mode.

[0059] The braking performance mode of the system 1 or the vehicle 100 corresponds to the operating mode of the system 1 described in relation to FIG. 1. The combined aerodynamic and braking performance mode of the system 1 or the vehicle 100 corresponds to the operating mode of the system 1 described in relation to FIGS. 2 and 3.

[0060] When high aerodynamic performance of the vehicle is required, for example on a highway at high speeds, the system 1 operates in combined aerodynamic and braking performance mode. The deflector 10 is then placed in the deployed position as shown in Figures 2 and 3.

[0061] For example, if the speed of the vehicle 100 is greater than or equal to a threshold value, in particular greater than or equal to 80 km / h, the placing of the system 1 and / or the vehicle 100 in a combined aerodynamic and braking performance mode can be carried out automatically.

[0062] The deflector 10 is then moved to the deployed position as shown in Figures 2 and 3, so that the deflector 10 can increase the airflow in the duct 6 in order to improve cooling. The shape of the duct makes it possible in particular to directly reach the disc at the location required for efficient cooling. The deployed position of the deflector 10 makes it possible to increase the flow and to fill the duct as much as possible. The deployed position of the deflector or wall also improves the aerodynamic performance of the vehicle by deflecting the incident air upstream of the wheel placed behind the deflector. This configuration thus allows for combined braking and aerodynamic performance. Several deployment positions can be envisaged h1 and h2 depending on the speed, the vehicle environment and the steering by the driver.

[0063] When even more efficient cooling of the brakes, in particular of a brake disc, of the vehicle is required, for example in the event of very sharp deceleration on the motorway, and the brake disc reaches a high temperature above a set temperature, despite the additional air sent by the deflector 10 into the duct producing cooling that would prove insufficient, provision may be made for the system 1 to be placed in braking performance mode. The deflector is in this case retracted, which is unfavorable for the aerodynamics of the vehicle, because this retraction then has the effect of allowing the incident air to pass in the direction of the wheel. The arrival of air at high speed directly on the wheel and the braking device further promotes cooling of the brakes and makes it possible to quickly lower the excessively high temperature of the braking device.Furthermore, if the temperature of the braking device becomes lower than the set temperature and the vehicle is still moving at a speed higher than the set speed, a return to the combined braking and aerodynamic performance mode can be considered with a redeployment of the deflector, thus allowing the duct to be supplied and filled with air.

[0064] In addition, when the vehicle's speed drops below the set speed, the deflector is fully folded down. Thus, at low speeds, the deflector is in the folded position, which makes it easier to cross speed bumps, especially in towns.

[0065] The method may thus comprise one or more steps of comparing the speed of the vehicle 100 with a threshold speed value for deploying the deflector 10 and one or more steps of comparing the temperature of the braking system with a threshold temperature for retracting the wall in the case of high speeds. The threshold speed value of the vehicle is for example of the order of 80 km / h. The threshold temperature value of the braking system is for example 680°C, a lower threshold temperature may be envisaged, 400°C for example.

[0066] The system thus has the advantage of being adaptable and offering several cooling possibilities depending on the condition of the vehicle.

[0067] It thus increases the cooling capacity of the brakes, by increasing the airflow in the duct while increasing aerodynamic performance, while allowing the possibility of strong cooling if necessary.

[0068] In addition, the system is easy to manufacture and / or assemble and has a low cost. Such a system has been described for one wheel, it is of course intended for the 2 front wheels of a vehicle 100.

[0069] Although the invention has been described above in the case of a braking system comprising a brake disc, the invention can be applied to other braking systems, for example to a drum brake system.

[0070] The invention advantageously makes it possible to optimize the compromise between high aerodynamic performance of the vehicle and high cooling capacity of the braking system or brakes, in particular of the brake discs of the vehicle during strong decelerations / accelerations on the highway. Thanks to the active control of the system, depending on the operating conditions of the vehicle, high aerodynamic performance of the vehicle or high cooling capacity of the brake discs at higher travel speeds and when the brakes are used can be easily obtained.

Claims

CLAIMS 1. System (1) for the controlled cooling of a braking system (3), in particular a brake disc (31) of a motor vehicle, comprising a duct (6), intended for an air flow, and a deflector (10), the duct (6) comprising an inlet opening (7) and an outlet opening (8), the deflector (10) being arranged downstream of the inlet opening (7) of the duct (6) along an internal face of the duct (6), the deflector (10) being movable between a position deployed outwards in the extension of the duct (6), said deployed position being such as to increase the incoming air flow, and a retracted position, in which it is folded inside the duct (6).

2. System (1) according to claim 1, wherein the movement of the deflector from the retracted position to the deployed position and from the deployed position to the retracted position is carried out by translation.

3. System according to the preceding claim, in which the translation of the deflector takes place in a substantially vertical direction (z) 4. System (1) according to one of claims 1 to 2 in which the main direction (A1) of the conduit (6) has an angle of inclination of between 30° and 60° relative to a longitudinal direction (X) of movement of the vehicle and the translation of the deflector (10) takes place in the extension of the conduit (6) in the direction (A1).

5. System (1) according to one of the preceding claims, in which the deflector (10) extends transversely over the entire width (w) of the duct (6).

6. System (1) according to one of the preceding claims comprising a motorization allowing the translational movement of the deflector (10). System (1) according to one of the preceding claims, in which the outlet opening (8) of the conduit (6) has a surface area smaller than that of the inlet opening (7) of the conduit (6) and the outlet opening (8) of the conduit (6) has a rectangular or substantially rectangular shape. System (1) according to the preceding claim, in which the conduit comprises a tubular section (62) made of flexible material. Motor vehicle (100) comprising a system (1) according to one of the preceding claims, the inlet opening (7) of the conduit (6) being located at a location on a base (23) of the vehicle (100), upstream of a wheel (2), the outlet opening (8) of the conduit (6) being located at a location opposite a brake disc (31) connected to said wheel, the conduit (6) being partly secured to the passage screen of said wheel, the deflector (10) being positioned between the inlet opening (7) and the wheel (2).Method of operating a system (1) according to one of claims 1 to 8 or of operating a vehicle (100) according to claim 9, comprising: - a step of comparing the speed of the vehicle (100) with a threshold value; and if the speed of the vehicle (100) is greater than or equal to the threshold value, placing the system (1) in a combined braking and aerodynamic performance mode in which the deflector (10) is in the deployed position; Operating method according to claim 10, comprising, in the case of a deployed deflector, a step of comparing the temperature of the braking system with a threshold value; and if the temperature of the braking system is greater than the threshold value, placing the system (1) in a braking performance mode in which the deflector (10) is in the retracted position.

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