WO2024084012A1

WO2024084012A1 - Brake disc protector

Info

Publication number: WO2024084012A1
Application number: PCT/EP2023/079203
Authority: WO
Inventors: Karthik-Aravind KRISHNAMURTHY; Christophe Magnin; Weiran Zhang
Original assignee: Renault S.A.S.; Nissan Motor Co., Ltd.
Priority date: 2022-10-20
Filing date: 2023-10-19
Publication date: 2024-04-25

Abstract

The invention relates to a device forming a brake disc protector for a vehicle, comprising a central base ring (Cbr) securing the device forming the brake disc protector to a non-rotatable vehicle structural element (K), a blade-type envelope having a substantially circular general shape with a maximum angular extent of approximately 300°, the blade-type envelope extending from one end of the central base ring (Cbr) and comprising a first structure (Sbi) extending in a plane substantially perpendicular to an axis of revolution of the central base ring (Cbr), the first structure (Sbi) comprising a first series of blades (Bi), each blade (Bi) of the first structure (Sbi) extending radially over the angular extent of the blade-type envelope with an angle of inclination with respect to the plane in which the first structure (Sbi) extends.

Description

DESCRIPTION

TITLE: Brake disc protector

Technical area

The invention relates to systems for improving braking performance and reducing damage to the material of a brake disc when used in a vehicle and more specifically for improving cooling of the brake disc.

A particularly interesting application of the invention concerns a sudden braking condition, which can affect the property of the material which in turn will degrade the braking performance, in the case where cooling is not sufficient.

Previous techniques

In the field of motor vehicles in the case of disc braking, it is necessary to regulate the temperature of the braking disc, so that the quality of braking is not degraded by excessive heating.

The brake disc reaches over 600 degrees during hard braking condition. Therefore, brake cooling performance is essential in determining the thermal load or critical temperature of the disc which can potentially affect the material property and desired shape of the disc. This will in turn degrade braking performance. To achieve the cooling performance criteria, hot air from the disk must be exhausted at a rapid rate.

To protect the braking tracks of the disc of a disc brake against splashes of water, mud or the like, it is known to protect them by surrounding the disc with a "disc protector" but this degrades the performance of the disc. cooling.

In US Patent 10,487,897, openings are formed on the main body of a brake dust cover to allow air to flow and cool the disc track, however the improvement in cooling performance remains limited with this solution.

Presentation of the invention

Considering the above issues, it is desirable to provide a disc protector that ensures brake cooling performance with a lightweight structure.

One aspect of the present invention relates to a brake disc protector device for a vehicle, particularly for a motor vehicle, comprising: a) a central base ring securing the brake disc protector device to a non structural rotary vehicle, b) a blade type envelope having a generally substantially circular shape having a maximum angular extent of approximately 300°, the blade type envelope extending from one end of the ring of central base and comprising a first structure extending in a plane substantially perpendicular to an axis of revolution of the central base ring, the first structure comprising a first series of blades, each blade of the first structure extending radially on the angular extent of the blade type envelope with an angle of inclination relative to the plane substantially perpendicular to an axis of revolution of the central base ring, and the first structure is secured to the central base ring. Thus, the extent of the blade type shroud is designed to provide a cutout on an angular portion of the circular area for a yoke space. Furthermore, the first structure extends in a plane parallel to a brake disc track surface and thanks to the angle of inclination each blade of the first structure extends radially in a plane not parallel to the surface of the brake disc. brake disc track so that they can expel hot air from the inner, or internal, track surface of the disc. This disc protector, which can also be one-piece, incorporating blade structures in front of the disc tracks, allows the brake disc to be cooled more quickly, over a larger area and more efficiently. Thus, hot air is no longer accumulated between the brake disc and the disc protector, no longer degrading the performance of the disc brake thanks to the blade structure design further exposing the disc to the ambient air.

Advantageously, the blade type envelope comprises arcs with a U-shaped profile overhanging the central base ring and in each arc a first branch of the two parallel U branches forms part of the first structure, and preferably a blade forming part of the first series of blades. Thus, the brake disc protector is configured to at least partially surround a brake disc, defining a volume in which the disc is located, partially enveloping it and covering exposed regions of the disc to protect them.

Advantageously, each U-shaped profile arc of the blade type envelope also includes:

- a second branch of U which is a blade forming part of a second series of blades of a second structure extending in a plane parallel to the plane in which the first structure extends, each blade of the second structure extends extending radially with an angle of inclination different from zero relative to the plane in which the second structure extends,

- a base of the U-shaped profile continuously connecting the first branch to the second branch is a connecting part forming part of the peripheral structure, the peripheral structure extends in a plane substantially perpendicular to the planes in which extend the first and second structures. Thus, the second structure extends substantially parallel to the brake disc track surface, and thanks to the angle of inclination its blades extend in a plane not parallel to the brake disc track surface so that they can expel hot air from the outer, or outer, track surface of the disc. Thus designed, the first structure is located further inside relative to the vehicle than the second structure and each second branch of the U-shaped profile arc is continuously attached to a blade of the first series via one of the connecting parts, the arc overhanging the central base ring.

Advantageously, the blades of the blade type envelope are flat and/or helical, either to simplify manufacturing or to improve the evacuation of hot air.

Advantageously, the second series of blades comprises more blades than the first series of blades, in order to better protect the internal disk track against splashes.

Advantageously, the blades of the blade type envelope are inclined relative to the plane in which the structure to which they belong extends by an angle of 30 to 60°, and preferably of 45°, this inclination of the surface Brake disc track improves cooling efficiency.

Advantageously, the central base ring and/or the blade type casing are made of metallic material or plastic material or ceramic material, so that they can withstand temperatures up to 300 “Celsius.

Advantageously, the blades forming part of a series of blades are spaced regularly in an angular manner, and preferably the spacing between two blades forming part of a series of blades is in the range of 2 to 23 degrees in angle, in order to better blow hot air out of the disc tracks.

Advantageously, the blades of the first series of blades are spaced regularly in an angular manner, and preferably the maximum spacing between two blades of the first series of blades is approximately 2.8 degrees in angle, in order to better protect the disc against splashes, mud or the like.

Advantageously, the blade length of at least some of the blades of the blade type casing is greater than or equal to a brake disc track width, in order to maximize the cooling surface on the disc track surface of brake and such that in the presence of an arc, the arc surrounds the disc.

Advantageously, the blade type envelope leaves a space of at least 1 millimeter, preferably at most 3 millimeters, with a brake disc track surface to better expel hot air from the disc track surface.

Advantageously, the second structure covers an angular extent less than the angular extent of the blade type envelope, partially overlapping the first structure of the blade type envelope, preferably its upper extent section, and preferably the angular extent of the second structure is a maximum of 180 degrees, in order to optimize the weight by limiting the second structure to the necessary cooling zone.

The subject of the invention is also a method of manufacturing a device forming a brake disc protector according to any one of the preceding claims, characterized in that it comprises, in combination, the following steps: a) - formation a central base ring and a blade type shroud, preferably by stamping from a metal plate or through a plastic injection molding process, or through a process of ceramic casting, and b) - assembly of the central base ring to the first structure of the blade type envelope, preferably by welding or brazing. This process does not require complex tools and ensures the robustness of the disc protector thus manufactured.

The subject of the invention is also a disc brake assembly comprising a steering knuckle of a wheel assembly, a caliper, a brake disc and a brake disc protector device according to the invention having the same qualities as mentioned previously.

The subject of the invention is also a motor vehicle comprising at least one disc brake assembly according to the invention, the vehicle structural element being the axle stub of a wheel assembly.

Brief description of the drawings

Other objects, characteristics and advantages of the invention will appear on reading the following description, provided only by means of a non-limiting example, and made with reference to the appended drawing in which: [Fig 1] is a basic diagram representing the environment of a brake disc in a vehicle according to the prior art with a classic disc protector; and [Fig 2a], [Fig 2b] and [Fig 2c] are schematic views of the disc, the caliper and the blades: top view, side view from the outside in the direction of the width of the vehicle , side view from the inside in the width direction of the vehicle; illustrating the position of the blades according to one embodiment of the invention, and [Fig 3] is a perspective view of the disc brake assembly illustrating the position of blades on each side of the disc in a preferred embodiment of the invention; and [Fig 4] is a side view of the disc brake assembly from the inside in the width direction of the vehicle in a preferred embodiment of the invention; and [Fig 5] is a top view of the disc brake assembly in a preferred embodiment of the invention; and [Fig 6] is a perspective view of the blade type casing from the outside in the width direction of the vehicle according to a preferred embodiment of the invention; and [Fig 7] is a perspective view of the blade type casing from the outside in the width direction of the vehicle according to another embodiment of the invention; and [Fig 8a] is a schematic cross-sectional view of a part of the disk protector according to a preferred embodiment of the invention and [Fig 8b] is a perspective view thereof; and [Fig 9a] and [Fig 9b] are perspective views of the disc brake assembly with and without the disc; and [Fig. 10] shows a comparison of the near-wall fluid temperature between a conventional disc protector and the disc protector according to a preferred embodiment of the invention; And [Fig. 1 1 ] represents a comparison of thermal transfer coefficient between a conventional disk protector and the disk protector according to a preferred embodiment of the invention.

Throughout the text, directions and orientations refer to a direct orthonormal reference frame XYZ, where X is the longitudinal direction of the vehicle, Y is the transverse direction of the vehicle, pointing outward from the vehicle and Z is the vertical direction pointing upwards. Throughout the description, the term "substantially" means that a slight deviation from a certain nominal position or orientation is admissible, for example "substantially vertical" means that a deviation of the order of 10° from a Strictly vertical orientation is permissible in the context of the invention, and the term "approximately" implies a tolerance of 5% from the nominal value indicated. For reasons of clarity, identical or similar elements are identified by identical reference signs in all figures.

Detailed description of at least one embodiment

As illustrated in [Fig 1], conventionally, in a vehicle, the disc brake, used while a vehicle is moving, comprises a brake disc D also called a disc brake rotor disposed on one side of inner diameter of a rim R of a wheel and a caliper C which interposes and retains the brake disc D with the brake pads P. In such a disc brake assembly, a conventional disc protector, in the form of a plate, CDP is arranged adjacent to the brake disc D facing the internal surface, or track, of the disc brake rotor in the width direction of the vehicle and so as to overlap at least part of the disc brake rotor, viewed from an axle direction of the wheel in an installed state where the disc protector is installed in the vehicle, in order to protect, for example, the disc against foreign matter such as dust, a small stone and l 'muddy water. A planar shape of the disc protector seen in the width direction of the vehicle is typically a shape of disc substantially concentric with the rotor or a sectoral shape provided with a cutout to produce space for the caliper C.

Such a conventional disc protector creates inhomogeneity in the disc, in particular between its distal track and its proximal track relative to the center of the wheel axle concerned, respectively also called external track and internal track, significantly decreasing the value of overall heat transfer coefficient of the internal track and also increasing the cooling constant, compared to a disc without protector.

According to the invention, the brake disc protector comprises:

- a central base ring fixing the brake disc protector device to a non-rotating structural vehicle element,

- a blade type envelope having a generally substantially circular shape having a maximum angular extent of approximately 300°, in order to provide a cutout on an angular part of the circular area for a stirrup space, the blade type envelope blades comprising a first structure extending substantially parallel to a brake disc track surface and comprising a first series of blades Bi, each blade of the first structure extending radially over the angular extent of the type envelope blades in a plane not parallel to the brake disc track surface and the first structure is secured to the central base ring.

The term blade refers to a wide, flat part used to push air, such as a propeller rotor or fan blade, and is used here as such to refer to an object that is flat, thin and long and by extension with a fin which is not necessarily flat.

The central base ring and/or blade type casing are made of metal, preferably aluminum or steel, or plastic which can withstand more than 300°C, or ceramic material. The central base may have the same characteristics with respect to the blade type casing of maximum angular extent of approximately 300°, preferably 270°C, in order to provide a cut out on an angular part of the circular area for a stirrup space.

In [Fig. 2a], the preferred embodiment with bilateral blade structures of the blade type shroud is sketched with only one blade on each side, to illustrate this embodiment with a simplified view. Each blade of the blade type casing extends radially in a plane not parallel to the brake disc track surface Ti, Te of the brake disc D. The blade Bi extends laterally from the proximal track towards the interior of the vehicle illustrates the preferred orientation of the first series of blades Bi, also called internal blades Bi. The blade Be extending laterally from the distal track towards the outer periphery of the vehicle illustrates the preferred orientation of the second series of blades Be, also called external blades Be. All the blades of a series virtually cross each other at the center of the axle spindle, whatever the orientation chosen, if they were connected to each other all the blades of each series of blades would form like a surface of revolution, the axis of revolution being the axis passing through the center of the central base ring perpendicular to the track surfaces, a surface of revolution being a surface in Euclidean space created by rotation of a curve (the generator) around a straight line in its plane (the axis).

Alternatively, the blade type casing may comprise only one series of blades and on the other side, in place of the other series of blades, would be a flat plate parallel to the disc track, of generally circular shape. having a maximum angular extent of approximately 300°, to provide a cutout on an angular portion of the circular area for a yoke space, but the cooling performance would be reduced compared to the preferred embodiment.

Each blade of the blade-type shroud extends radially in a plane not parallel to the brake disc race surface, with the main surface of the blade extending either perpendicular to the disc races, for protection purposes mainly, either in a way inclined relative to the brake disc track surface, preferably at an angle of inclination Bsa of 30 to 60°, for protection and cooling purposes, and in particular of 45° as presented here, where each blade is inclined at a 45 degree angle to the track surface, either positively or negatively, acting as disc vents. As shown below, in Figure 3, both the inner and outer side blades are connected to each other using a connecting element on the periphery of the disc vents. The inclination and orientations of the blades can also be different for the first series of blades and the second series of blades provided that, in the same series, all the blades extend radially following the same angle of inclination, also called orientation inclination with sign, relative to the surface track.

As shown here, the preferred embodiment consists of blades symmetrical with respect to the plane of symmetry Ps which is the median plane of the disk tracks parallel to the disk tracks Ti, Te. Preferably, the blade edges and disc surface should maintain one to three millimeters of tolerance space. This offset of 1 millimeter between the blades, more precisely between their edges, parallel to the disc tracks and near the disc, and the respective track surface facing them is shown in the figure relative to the proximal track Ti and the blade Bi and symmetrically on the other side between the blade Be and the distal track Te. This offset, of approximately 1 millimeter between the track surface and the blade edges and of at least 3 millimeters between the disc circumference and the connecting parts, more generally delimits the limit of the arcs. The blades split the hot air onto the disc, so they need to be as close as possible, so G space is necessary but the smaller it can be the more cooling is optimized. Shown here, as an example, the blade height Bh is 10 millimeters and their pitch height Bsh is 7.1 millimeters.

In Figures 2b [Fig. 2b] and 2c [Fig. 2c], side views from the outside in the width direction of the vehicle and a side view from the inside in the width direction of the vehicle, are illustrated the preferred blade stacking patterns, for the first series of blades in Figure 2c and for the second series of blades in Figure 2b, the blades Bi, Be being distributed repeatedly at small angular intervals so that they cover the entire track surface with the exception of the angular section covered by the stirrup C. The internal blades Bi and/or external Be are spaced angularly and preferably regularly, and preferably the maximum spacing between two blades in one of the first and/or second sets is approximately 23 degrees in angle for cooling performance reasons. More precisely, the maximum angle between two blades Bi, Be is a quarter of a quarter circle: 22.5°. Thus distributed in a dispersed manner, as shown here in Figure 2b for the external blades Be, with an angular spacing Beas of 22.5° between the consecutive external blades Be. The blades provide a reduction in weight and thus a reduction in fuel consumption since they reduce the weight of the unsprung mass of the vehicle, which will typically improve the way the vehicle drives and its handling. In a preferred embodiment, to improve cooling on the internal side, the internal blades Bi are distributed in a tight manner, the internal blades being evenly spaced angularly with a maximum spacing between two blades of the first series of blades Bi d 'approximately 2.8 degrees in angle and more precisely with a spacing of 22.5°/(7 + l) allowing 7 internal blades Bi to be placed between the internal blades Bi which are extended by the connecting parts. Thus, distributed densely, as shown here in Figure 2c for the internal blades, with an angular spacing Béas of 2.8° between the blades Bi, the blades Bi act as a disc protector, for example in the event of splash, which removes the need to provide a dedicated external mudguard since it covers the projected area on the disc, and thus allowing a reduction in weight and thus a reduction in fuel consumption.

Preferably, both the inner blade length Bi and the outer blade length Be should be greater than or equal to the track width to achieve maximum efficiency on the disc track area.

In [Fig. 3] the perspective view of the disc brake assembly represents the caliper C, the steering knuckle K of a wheel assembly, the disc having its external track Te and the blade type casing with its Bi, Be bilateral blade structures surrounding the disc, and having a generally substantially circular shape, comprising U-shaped profile arcs, at least partially surrounding the brake disc, with a maximum angular extent of approximately 300° in order to provide a cutout on an angled portion of the circular area for a stirrup space. Each blade Bi, Be of the blade type envelope extends radially in a plane not parallel to the brake disc track surface Ti, Te, and as a preferred embodiment illustrated here, the two branches of U parallel blade type casing consists of blades only. In this image of a preferred embodiment, the three parts of the blade type envelope are clearly visible:

- a first structure Sbi defining a surface extending substantially parallel to the distal track surface Te of the brake disc, the first structure Sbi comprising a first series of blades Bi,

- a second structure Sbe defining a surface extending substantially parallel to the proximal track surface Ti of the brake disc, preferably the second structure Sbe comprising a second series of blades Be, the first structure Sbi corresponding to the proximal structure relative to the center of the wheel axle concerned, in other words, located further inside relative to the vehicle than the second structure Sbe,

- a peripheral structure Sp connecting the first structure Sbi to the second structure Sbe defining connecting parts whose surface is substantially perpendicular to the track surface Ti, Te of the brake disc and parallel to the local tangent to the disc D, each blade Be of the second series being continuously attached to a blade Bi of the first series by one of the connecting parts. On this figure, the second structure Sbe with its blades Be stacked on the upper half of the disk on the external side is better represented, the second structure covering an angular extent less than the angular extent of the blade type envelope due to the angular extent of the first structure, better visible in the following figure, and preferably the angular extent of the second structure is a maximum of 180 degrees, overlapping the upper extent section of the first structure of the envelope of blade type. Here, the space between the two Be blades is 1 1.25 degrees in angle.

The arrow represents the direction of rotation of the disc, known as counterclockwise rotation, and the dotted line represents the axis of rotation of the disc. The disc, as it spins, will cause the air around it to spin with it. The swirling air receives heat from the disk and behaves like a warm blanket on the disk. This warm blanket of air dissipates much less heat to the surrounding air, acting as a thermal resistive layer. An effective solution is to disrupt this layer, so that fresh cold air from the environment can remove more heat from the disk. The blade design according to the invention prevents the air from rotating with the disc and therefore they act as air flow separators. Flow separation increases turbulence in the airflow, which improves the mixing of cold and warm air. This in turn results in increased cooling performance. In a preferred embodiment of the invention illustrated here, the Bi blades are densely distributed on the internal side to have the functionality of a disc protector while, on the external side, the Be blades are distributed densely. dispersed to focus only on the single flow separation functionality. A rim, in particular a semi-openwork or full rim, can also be added to this external side.

[Fig 4] shows a side view of the disc brake assembly from inside the vehicle in the width direction of the vehicle, as from the center of the relevant wheel axle. We see in this view the axle journal K, the caliper C, the proximal track Ti, or internal, and the internal blades Bi, spaced here regularly with a space of 2.8° between each of them and covering the extent of 270°. In this embodiment, the total number of blades will be approximately 80 but it may vary with the configuration and design of the disc and caliper. The arrow represents the direction of rotation of the disc.

In [Fig 5] the disc C, the caliper C and the blade type envelope secured to the axle knuckle K and the peripheral structure Sp made up of connecting parts Bp connecting the first structure to the second are represented structure acting as transverse fixings.

[Fig 6] represents a perspective view of the blade type envelope from the outside in the width direction of the vehicle in a preferred embodiment of the invention. The arrow represents the direction of rotation of the disc. The architecture of the blade type envelope made up of three parts of the blade type envelope appears clearly as does the continuity between the first structure Sbi, the peripheral structure Sp and the second structure Sbe thanks to the blades Bi of the first structure Sbi connected via connecting parts Bp of the peripheral structure Sp to blades Be of the second structure Sbe. In this figure, the characteristic of lightness stands out clearly.

Alternatively, as shown in [Fig. 7], the blade type envelope can comprise two series of blades Bi Be, and one of them, preferably the internal blades Bi, is supported by a flat plate Fpi of generally circular shape parallel to the track Ti internal disc and facing it, with the same extent as the first series of blades Bi, with a maximum angular extent of approximately 300° in order to provide a cutout on an angular part of the circular zone for a space of ' yoke. Here, the flat plate Fpi and the internal blades Bi form the first structure Sbi. The flat plate Fpi behaves as a circumferential peripheral cover of the internal blades Bi on the proximal side (relative to the center of the wheel axle) of the disc protector when assembled to the vehicle, which helps protect the disc against splashes. The proximal end (relative to the center of the wheel axis) of the internal blades Bi is secured, preferably welded, to the flat plate. In this case the blades Bi are distributed angularly regularly but less densely than shown in the previous figures, for example with intervals of 1 1° between them like the external blades Be. The arrow represents the direction of rotation of the disc. This variant better protects against splashes and improves robustness with respect to noise and vibration criteria. Furthermore, the parallel flat plate can be semi-perforated to improve cooling and weight without degrading anti-splash effectiveness.

In [Fig. 8a] is a schematic cross-sectional view of a part of the disc protector according to a preferred embodiment of the invention illustrating the U-shaped arc and the attachment of the blades Bi of the first structure Sbi to the ring of central base Cbr fixed. As shown here, the central base ring Cbr consists of a first annular plate, encircling the steering knuckle K and attached to the steering knuckle, with a projection consisting of a circumferential lateral offset extension towards the axle of the axle. wheel (when the disc protector is installed in the vehicle). This circumferential lateral offset extension, starting from the internal periphery (relative to the vehicle) of the first annular plate, consists of a second substantially vertical annular plate extended by a third substantially horizontal annular plate forming an L-shaped projection Cbr_Ls around the first annular plate, the diameter of the central base ring Cbr being at this end slightly larger than the diameter of the first annular plate and preferably covers the same angular extent as the extent of the blade type envelope. The role of the horizontal annular plate is to be a lower base for retaining the internal blades Bi so that the width (extended in the Y direction, perpendicular to the disk surface) of this second annular plate is at least the width of pale. The method of manufacturing such a brake disc protector device comprises, in combination, the following steps: a) - formation of a central base ring Cbr and a blade type casing, preferably by stamping a metal plate or through a plastic injection molding process, or through of a ceramic casting process, and b) - assembly of the central base ring Cbr to the first structure Sbi of the blade type envelope, the central base ring Cbr being for example welded or bolted, and/ or preferably adjusted by tightening on the axle stub K.

The horizontal annular plate acts as a fixing plate retaining the central ends of the internal blades Bi. Thus, in the first stage, when the blades are separate parts of the central base ring Cbr, the central ends of the blades are attached to the central base ring, for example by resistance welding or brazing or arc welding under gas protection. Preferably, diagonal slots are cut in the base ring to obtain the preferred inclination angle of 45°, then the first end of each of the blades Bi is slipped into the slots and adjusted by clamping, and the joints are welded or brazed with heat to firmly secure the internal blades Bi to the central base ring Cbr. Then some of the blades, preferably one in 8, are approximately twice as long and folded in a U shape to create the arcs, or alternatively some of the blades Bi are fixed perpendicularly, by welding for example, to connecting parts Bp, themselves fixed perpendicularly, by welding for example, to external blades Be, to form the arcs. Alternatively, the manufacturing process may follow a sheet metal forming process, such that the central base ring Cbr and the blades are one piece. In this variation, the L-shaped edge of the central base ring is extruded to the maximum required length of the blade (approximately twice the length of the internal blades) forming like a tube, the extruded region is cut into regular intervals equal to the required height of the blade (which are not necessarily all the same length, as explained previously to form the arcs), and the blades are bent 90° radially outwards until they cover the required extent (the others are cut at their base), the base region of the blade is inclined to give the blade angle a slope of 45 °, and the arc formation process remains the same as previously stated, the disc protector being in one piece here.

In this image the U-shaped profile is clearly visible, the external blades Be are overhanging and are held in place thanks to the peripheral structure Sp at one of their ends. Each end of the external blade Be opposite the connecting parts Bp is thus free, and is not connected to any other fixing elements connecting them to the axle knuckle K. The rigidity of the U-shaped profile is proportional to the thickness blades. Therefore blades of appropriate thickness of at least 1 mm will withstand driving situations without vibrating. However, regardless of the thickness of the blades, the Bp connecting parts of the U-profile arches can be reinforced with transverse stiffeners to improve robustness and prevent vibrations at high vehicle speed. For example, as shown in the perspective view of [Fig. 8b], the three free corners of consecutive arcs are connected to each other using connecting metal sheets as transverse stiffeners S, while the fourth corner is fixed to the central base ring Cbr by default. In this case, this implies that the free ends of the internal blades Bi which are not part of the U-shaped arcs are subject to one of the transverse stiffeners S.

In the various images the blades of the blade type casing are designed to be flat for better understanding of the drawings, but they can also be designed helically, like fins arranged in a spiral around an axis . Furthermore, in the presence of stiffeners, the connecting parts Bp can be more easily twisted or made not only perpendicular to the track surface Ti, Te of the brake disc but also perpendicular to the local tangent to the disc D, in order to improve cooling since the connecting parts Bp perpendicular to the track surface Ti, Te of the brake disc and parallel to the local tangent to the disc D slightly obstruct the air flow. In [Fig. 9a] is shown the disc assembly (without the caliper for purposes of clarity) comprising the disc D, the fixed axle knuckle K and the disc protector according to another embodiment of the invention. Figure 9b [Fig. 9b] is the same figure without the disk. In this embodiment of the invention, the second structure Sbe of the external blades Be covers not only the upper half of the disk D but the entire extent, or angular arc, of the blade type envelope, which means that the extent of the disc apart from the angular zone remains open for the caliper C. The central base ring Cbr is fixed, encircling the steering knuckle K and attached to the steering knuckle.

[Fig. 10] shows the near-wall fluid temperature comparison in a use case at a constant vehicle speed of 80 kmph, between a conventional CDP disc protector, in the left column, and the DPI disc protector according to the preferred embodiment of the invention (as in Figures 3 to 6), in the right column, for the internal track Ti in the first line, and for the external track Te in the second line. It is clear that on the inner Ti track side the disc protector traps hot air in the narrow space (here 1 millimeter) between the disc protector and the Ti disc track. The arrow represents the direction of rotation of the disc. The blades are open to the ambient air and separate the hot air attached to the disc, so the temperature of the air near the wall drops in the range of 100 °C to 135 °C, and at the side of the track external Te, in the absence of the disk protector portion in the conventional CDP design, a uniformly distributed temperature of 135 °C is observed, while, in the preferred embodiment DPI, the blades separate the flow of warm air and help the cold ambient air to mix and reduce the temperature of the air near the wall to 100 °C.

In [Fig. 1 1 ] the heat transfer coefficient (HTC) is compared, in a case of use at a constant vehicle speed of 80 kmph, between a conventional CDP disc protector (left column) and the DPI disc protector according to a embodiment preferred (as in Figures 3 to 6) of the invention (right column), with regard to the internal track Ti in the first line, and the external track Te in the second line. The arrow represents the direction of rotation of the disc. On the inner track side, an HTC of about 75 W/(m ² .K) is observed with the classic CDP protector, while in the preferred embodiment DPI the blades increase the HTC up to almost 100 W/(m ² .K) . This represents an improvement of approximately 25% in this region. On the outer track side, with the classic CDP protector, the caliper itself acts as a major flow separator which itself improves the HTC in the lower half of the disc. Therefore, in the preferred DPI embodiment in which blades are present on the remaining region of the disk track, it is observed that due to the blades the HTC increases from 75 W/(m ² .K) to 100 W/ (m ² .K).

The disc is rotating (rotator) and the blades are static (stator), which creates a relative movement of the disc with respect to the blades, which is similar to the behavior of a disc held static and blades as rotating parts, and in either case the blades behave like a fan in front of the disc. The brake cooling performance of the preferred embodiment according to the invention is also evaluated through the time constant, also called cooling constant. For example, in a case where the brake disc tracks are initialized at 600°C and are allowed to cool down to 200°C, the cooling time period from 555°C to 200°C is evaluated, and a difference of 80 seconds is obtained between the conventional disk protector case and the preferred embodiment.

Claims

1. Brake disc protector device for a vehicle, in particular for a motor vehicle, comprising: a) a central base ring (Cbr) fixing the brake disc protector device to a non-rotating element (K) structural vehicle, b) a blade-type casing having a generally substantially circular shape having a maximum angular extent of approximately 300°, the blade-type casing extending from one end of the base ring central (Cbr) and comprising a first structure (Sbi) extending in a plane substantially perpendicular to an axis of revolution of the central base ring (Cbr), the first structure (Sbi) comprising a first series of blades (Bi) , each blade (Bi) of the first structure (Sbi) extending radially over the angular extent of the blade-type envelope with an angle of inclination relative to the plane in which the first structure (Sbi) extends ), and the first structure (Sbi) is secured to the central base ring (Cbr).

2. Brake disc protector device according to claim 1, wherein the blade type casing comprises U-shaped profile arcs overhanging the central base ring (Cbr) and in each arc a first branch of the two parallel U branches are part of the first structure (Sbi), and preferably a blade (Bi) forming part of the first series of blades.

3. Brake disc protector device according to claim 2, wherein each U-shaped profile arc of the blade type envelope also comprises:

- a second branch of U (Be) which is a blade (Be) forming part of a second series of blades (Be) of a second structure (Sbe) extending in a plane parallel to the plane in which extends the first structure, each blade (Be) of the second structure (Sbe) extending radially with an angle of inclination relative to the plane in which the second structure (Sbe) extends, - a base (Bp) of the U-shaped profile continuously connecting the first branch (Sbi) to the second branch (Sbe) is a connecting part (Bp) forming part of the peripheral structure (Sp), the peripheral structure (Sp) extends in a plane substantially perpendicular to the planes in which the first (Sbi) and second (Sbe) structures extend.

4. Device forming a brake disc protector according to any one of claims 1 to 3, in which the blades (Bi, Be) of the blade-type envelope are flat and/or helical.

5. Device forming a brake disc protector according to any one of claims 3 and 4, wherein the second series of blades (Be) comprises fewer blades than the first series of blades (Bi).

6. Device forming a brake disc protector according to any one of claims 1 to 5, in which the blades (Bi, Be) of the blade-type envelope are inclined relative to the plane in which the structure extends to which they belong (Sbi, Sbe) at an angle of 30 to 60°, and preferably 45°.

7. Device forming a brake disc protector according to any one of claims 1 to 6, wherein the central base ring (Cbr) and/or the blade type casing are made of metallic material or plastic material or of ceramic material.

8. Device forming a brake disc protector according to any one of claims 1 to 7, in which the blades (Bi, Be) forming part of a series of blades are spaced regularly in an angular manner, and preferably the spacing between two blades forming part of a series of blades is in the range of 2 to 23 degrees in angle.

9. Device forming a brake disc protector according to any one of claims 1 to 8, in which the blades (Bi) of the first series of blades are spaced regularly in an angular manner, and preferably the maximum spacing between two blades making part of the first set of blades is approximately 2.8 degrees in angle.

10. Brake disc protector device according to any one of claims 1 to 9, wherein the blade length of at least some of the blades (Bi, Be) of the blade type casing is greater than or equal to at a brake disc track width (Ti, Te).

1 1 . Device forming a brake disc protector according to any one of claims 1 to 10, in which the blade type envelope leaves a space of at least 1 millimeter, preferably at most 3 millimeters, with a surface (Ti , Te) of brake disc track.

12. Device forming a brake disc protector according to any one of claims 3 to 1 1, in which the second structure covers an angular extent less than the angular extent of the blade type envelope, partially overlapping the first structure (Sbi) of the blade type envelope, preferably its upper extent section, and preferably the angular extent of the second structure (Sbe) is a maximum of 180 degrees.

13. Method of manufacturing a device forming a brake disc protector according to any one of the preceding claims, characterized in that it comprises, in combination, the following steps a) - formation of a central base ring and of a blade type casing, preferably by stamping from a metal plate or through a plastic injection molding process, or through a ceramic casting process, and b) - assembly of the central base ring to the first structure (Sbi) of the blade type envelope, preferably by welding or brazing.

14. Disc brake assembly comprising a steering knuckle of a wheel assembly (K), a caliper (C), a brake disc (D) and a brake disc protector device according to any one of claims 1 to 12.

15. Motor vehicle comprising at least one disc brake assembly according to claim 14, the vehicle structural element being the steering knuckle of a wheel assembly.