BRAKE DISC

Description

DESCRIPTION of the invention entitled: “BRAKE DISC” in the name: Brembo SGL Carbon Ceramic Brakes SpA with headquarters in: Viale Europa 2 – 24040 Stezzano (BG) 5 Designated Inventors: Daniel Angel PALOMINO SOLIS, of Italian nationality Luca MENINI, of Italian nationality ________________________________________________________________ Field of invention The present invention relates to a brake disc for disc braking systems. In 10 In particular, the invention relates to brake discs for high-performance vehicles, equipped with a crown or braking band made of carbon matrix composite material, coaxially and internally to which a bell-shaped metal element is provided, in solidarity with it. Known technique 15 The following documents describe some examples of braking systems in particular equipped with a braking band made of carbon matrix composite material: WO2019043616 and WO2016 / 199021. Summary of the invention As is known, the so-called carbon matrix discs are also commonly known as 20 carbon discs or carbon ceramic discs. Brake discs may comprise a braking band and a bell made of separate pieces assembled using at least one device connection. The connection between the braking band and the bell is very important because it guarantees the 25 transfer of braking torque from the braking band to the bell. The constraint tangential between braking band and bell can be achieved with systems that They feature protrusions on the braking band that fit into respective seats on the bell in order to create a tangential constraint system between the braking band and bell having a particularly simple structure and therefore low manufacturing costs 30 production. The Applicant also observed that another particularly important aspect in the design of disc brakes is given by ventilation. It is in fact known that to maximize the heat extracted from the brake disc, it is important that the air flow inside the ventilation ducts so as to ensure leaks 5 of load as small as possible, and in order to maximize the exchange thermal and the flow rate of cooling air, which overheats and exits the radially outer edge of the braking band of the rotating disc brake. The Applicant therefore faced the problem of creating a brake disc that would allow optimize the ventilation of the brake disc, and in particular the heat exchange 10 inside the ventilation channels. In a first aspect, the invention therefore refers to a brake disc comprising a bell and a braking band radially external to the latter, the band and the bell extending around a common axis of rotation; the braking band being made of composite material and featuring lateral braking surfaces suitable for 15 cooperate with a relative brake caliper by exerting a braking action on the vehicle on which said brake disc is installed; said lateral surfaces also defining, a plurality of ventilation channels arranged away from the axis of rotation, said ventilation channels extending along a direction of extension between a radially internal air opening and one radially external air opening 20 characterized by the fact that said ventilation channels include in separation from said axis of rotation at least one rectilinear section and at least one curvilinear section arranged consecutively to the straight section; - said rectilinear section having a greater extension than said curvilinear section; said curved section flowing into said radially external air opening. 25 The Applicant has thus obtained a new optimization of the heat exchange and therefore of the cooling of the air flowing inside the ventilation ducts. For the purposes of this invention, the following definitions apply: By “axial direction” is defined a direction that is substantially coincident or substantially parallel to the axis of rotation of the brake disc. 30 By “radial direction” is meant a direction substantially orthogonal to the axial direction. By “tangential or circumferential direction” is meant an orthogonal direction either both in the axial and radial directions. The present invention, in one or more preferential aspects, may comprise one or more 5 of the features listed below. Preferably, the aforementioned at least one straight section has a greater extension of or equal to 55% of the overall extension of the ventilation duct and less than or equal to 90% of the overall extension of the ventilation duct. Advantageously, the aforementioned at least one straight section has an extension 10 greater than or equal to 70% of the overall extension of the ventilation duct. Advantageously, the aforementioned at least one straight section can extend in moving away from the axis of rotation in a direction of extension so as to form a first inclination angle α' with a radial direction to the axis of rotation less than or equal to 60°. 15 Preferably, the first inclination angle can be constant along the extension of the first section of the ventilation duct. Conveniently, the aforementioned at least one curved section extends away from the axis of rotation XX according to a direction of extension so as to form a second inclination angle α'' with a radial direction to the minor rotation axis 20 of the first inclination angle α'. Advantageously, the second inclination angle α'' is less than or equal to 50° and greater than or equal to 10°. Preferably, the second inclination angle α'' varies in a decreasing manner in distance from the axis of rotation along the extension of said second section. 25 Alternatively, the said at least one curvilinear segment extends away from the axis of rotation according to a direction of extension so as to form a second inclination angle α'' with a radial direction to the axis of rotation greater than the first inclination angle α'. Preferably, in this case the second inclination angle α'' is less than o 30 equals 90° and greater than or equal to 70°. Conveniently, the ventilation channels comprise an increasing width in radial departure from said axis of rotation. Advantageously, the width of the curved stroke can be greater than or equal to deLr, where Lr is the maximum width of the straight section. 5 Preferably, the width of the curved section may be less than or equal to 5 Lr. Further features and advantages of the invention will become more apparent from the detailed description of some preferred, but not exclusive, embodiments of a brake disc according to the present invention. Brief description of the drawings 10 This description will be set out below with reference to the attached drawings, supplied to for indicative purposes only and therefore not limiting, in which: - Figure 1 shows a schematic perspective view of a braking band of a first embodiment of the brake disc according to the invention; - figure 2 is a side sectional view of the braking band of figure 1; 15 - Figure 3 is a schematic cross-sectional view of the braking band taken according to the MM section plane of figure 2; - Figure 4 is an enlarged schematic view of a portion of the braking band of figure 3. Detailed description of embodiments of the invention 20 With reference to the attached figures, 1 indicates a brake disc as a whole according to the present invention. The brake disc 1 comprises and is made up of a metal bell 2 and a band braking 3 radially external to the latter. The metal bell 2 and the braking band 3 extend around a common axis 25 rotation center indicated by XX. The rotation axis defines an axial direction XX coincident or parallel to the axis of rotation, a radial direction RR orthogonal to the axial direction XX, and a tangential direction TT or circumferential TT, orthogonal to both the axial direction XX than the radial one RR. The braking band 3, made of composite material such as type carbon ceramic, is equipped with two lateral braking surfaces indicated with 4, suitable to be engaged by a brake caliper (not shown) of a disc brake system. Between the two lateral surfaces 4 belonging to the braking band 3 a 5 plurality of ventilation channels 5. The ventilation channels 5 extend away from the axis of rotation XX towards the radially outer edge of the braking band 3. Each ventilation channel 5 comprises at least one radially internal air opening 6 facing the axis of rotation XX, a radially external air opening 7, arranged in correspondence 10 of the radially outer edge of the braking band 3. Each radially internal air opening 6 has an area greater than or equal to 36 mm . Each radially external air opening 7 has an area greater than or equal to to the area of ​​the radially internal air opening 6. 15 Each radially external air opening 7 has an area less than or equal to 700 mm . Each ventilation channel 5 has a maximum height H, measured according to a direction parallel to the axis of rotation XX, greater than or equal to 5 mm. Preferably, the maximum height H of the ventilation duct is less than or equal to 20 30 mm. Each ventilation channel 5 also comprises one or more side walls 5' arranged, according to the direction of extension, between the radially internal air opening 6 and the radially external air opening 7. The 5' side walls, arranged around the direction of extension, define 25 laterally the ventilation channel itself. In the embodiment shown in the figures, there are four side walls 5' two by two facing each other. According to this embodiment, the ventilation channel 5 has, in fact, a substantially quadrangular section. Preferably, the ventilation channels 5 do not have a constant cross-section, along their direction of extension, but a cross-section that increases at least in correspondence of the first segment 11 moving away from the axis of rotation XX. By cross-section of a ventilation duct 5 is meant a section of the duct 5 ventilation 5, substantially, orthogonal to the direction of extension of the channel ventilation 5 same. The ventilation channels 5, moving away from the axis of rotation XX, are formed by a straight section 11 and a curved section 12 arranged consecutively to the section straight 11. 10 The straight section 11 extends from the radially internal opening 6 and has an extension greater than the curved section 12, the latter as visible in the attached figures flows in the radially external air opening 7. Preferably, each ventilation channel 5 is formed only by the straight section 11 and from the curved section 12 and there are no further typologies, by shape or size 15 sections of ventilation duct. As previously mentioned, the straight section 11 of the ventilation duct 5 has a preponderant extension compared to the curvilinear section 12 and in general compared to the total extension of the ventilation channel 5 itself. Preferably, the straight section 11 has an extension greater than or equal to the 20 55% of the total extension of the ventilation duct 5 and less than or equal to 90% of the overall extension of the ventilation duct 5. More preferably, the straight section 11 has an extension greater than or equal to 60% of the total length of the ventilation duct 5. Even more preferably, the straight section 11 has an extension greater than o 25 equals 70% of the overall extension of the ventilation duct 5. In the straight section 11 each ventilation channel 5 has an increasing width radially away from the axis of rotation XX. The maximum width Lr of the straight section 11 is preferably between 5 mm and 50 mm. Preferably the straight section 11 extends away from the axis of rotation XX according to a direction of extension capable of forming a first angle of inclination α' with a radial direction to the rotation axis XX less than or equal to 60°. Preferably, the first inclination angle α' is greater than or equal to 15°. Again 5 more preferably, the first inclination angle α' is greater than or equal to 30° and less than or equal to 50°. Preferably, the first inclination angle α' is substantially constant throughout the extension of the straight section 11. As previously mentioned, the straight section 11 of the ventilation duct 5 is 10 followed radially away from the rotation axis XX by a curved segment 12. The curved section has a smaller extension than the first straight section 11. Preferably, the curved section 12 has an extension greater than or equal to the 5% of the total extension of the ventilation duct 5 and less than or equal to 30% of the overall extension of the ventilation duct 5. 15 Even more preferably, the curved section 12 has an extension smaller than o equal to 15% of the overall extension of the ventilation duct 5. In the embodiment shown in the figures, the curved section 12 of each ventilation channel 5 has a substantially constant or slightly variable width increasing in radial distance from the axis of rotation XX. 20 The maximum width Lr of the curved section 12 is preferably between 5 mm and 100 mm. With reference to the preferred embodiment shown in the figures, the section curvilinear 12 extends away from the axis of rotation XX according to a direction of extension capable of forming a second inclination angle α'' with a 25 radial direction to the axis of rotation XX less than the first inclination angle α' of the straight section 11. Preferably, the second inclination angle α'' is less than or equal to 50° and greater than or equal to 10°. The second inclination angle α'' varies decreasingly as one moves away 30 from the axis of rotation XX along the extension of the curved section 12. According to an alternative embodiment, not shown in the figures, the section curvilinear 12 could extend away from the axis of rotation according to a direction of extension so as to form a second inclination angle α'' with a radial direction to the axis of rotation greater than the first inclination angle α'. 5 Preferably, in this case the second inclination angle α'' is less than o equal to 90° and greater than or equal to 70°. In other words, according to this embodiment, the curved section extends circumferentially in a direction opposite to that shown in the figures. The brake disc 1 also comprises a bell 2, suitable for being operationally 10 connected to a vehicle wheel that can be associated with braking band 3. The braking band 3 is equipped with a radially internal ring, preferably flat and continuous 10 where MM indicates the median plane. The continuous inner ring 10 has two lateral faces 8,9, of which with reference to the figure 1, one facing upwards 8 and one facing downwards 9. 15 The inner ring 10 may have at least one coupling element 23 which is develops substantially orthogonally to the median plane MM starting from a lateral face 8 of the inner ring 10. With reference to figures 2 and 3 and in accordance with the preferred embodiment, the inner ring 10 has not just one, but a plurality of elements of 20 coupling 23 distributed along a concentric coupling circumference 20 to the central axis of rotation XX. The coupling elements 23 provide a seat for housing means of coupling 24, typically screw coupling means, and are configured for allow the coupling between metal bell 2 and braking band 3. 25 The coupling elements 23 are spaced angularly, preferably so constant along the circumference, called the coupling circumference 20. Preferably, there are eight to fourteen coupling elements 23 per brake disc 1, even more preferably there are nine to thirteen elements of coupling 23 for brake disc 1. Thanks to the features described above, provided separately or in combination, it is possible to provide a solution to the brake disc cooling needs with an optimization of the heat exchange inside the ventilation ducts. Various modifications may be made to the embodiments described in the 5 detail, while remaining within the scope of protection of the invention, defined by the following claims.

Claims

CLAIMS 1. Brake disc (1) comprising a bell (2) and a braking band (3) radially external to the latter, said braking band (3) and said bell (2) extending around a common rotation axis (XX); said braking band (3) presenting lateral braking surfaces (4) suitable for cooperating with a relative brake caliper, exerting a braking action on the vehicle on which said brake disc (1) is installed;said lateral surfaces (4) further defining a plurality of ventilation channels (5) arranged away from the rotation axis (XX), said ventilation channels (5) extending along a direction of extension (ZZ) between a radially internal air opening (6) and a radially external air opening (7) characterised in that said ventilation channels (5) comprise away from said rotation axis (XX) at least one rectilinear section (11) and at least one curvilinear section (12) arranged consecutively to said rectilinear section (11); - said rectilinear section (11) having a greater extension than said curvilinear section (12); said curvilinear section (12) flowing into said radially external air opening (7).; 2. Brake disc (1) according to claim 1, characterised in that said at least one straight section (11) has an extension greater than or equal to 55% of the overall extension of the ventilation channel (5) and less than or equal to 90% of the overall extension of said ventilation channel (5).

3. Brake disc (1) according to claim 2, characterised in that said at least one straight section (11) has an extension greater than or equal to 70% of the overall extension of the ventilation channel (5).

4. Brake disc (1) according to claim 3, characterised in that the said at least one straight section (11) extends away from the axis of rotation (XX) according to an extension direction (ZZ) so as to form a first inclination angle α' with a radial direction to the axis of rotation (XX) less than or equal to 60°.

5. Brake disc (1) according to claim 4, characterised in that said first inclination angle α' is substantially constant along the extension of said straight section (11).

6. Brake disc (1) according to claim 3, characterised in that said at least one curvilinear section (12) extends away from the axis of rotation (XX) according to an extension direction (ZZ) so as to form a second inclination angle α'' with a radial direction to the axis of rotation (XX) smaller than said first inclination angle α'.

7. Brake disc (1) according to claim 3, characterised in that said at least one curvilinear section (12) extends away from the rotation axis (XX) according to an extension direction (ZZ) so as to form a second inclination angle α'' with a radial direction to the rotation axis (XX) greater than said first inclination angle α'.

8. Brake disc (1) according to claim 6, characterised in that said second inclination angle α'' is less than or equal to 50° and greater than or equal to 10°.

9. Brake disc (1) according to claim 7, characterised in that said second inclination angle α'' is less than or equal to 90° and greater than or equal to 70°.

10. Brake disc (1) according to claims 6 or 7, characterised in that said second inclination angle α'' varies in a decreasing manner away from said axis of rotation (XX) along the extension of said second section (12).

11. Brake disc (1) according to any of the preceding claims 1 to 8, characterised in that said ventilation channels (5) comprise a width increasing radially away from said axis of rotation (XX).

12. Brake disc (1) according to claim 9, characterised in that the width of said curved section (12) is greater than or equal to Lr, where Lr is the width of said straight section (11).

13. Brake disc (1) according to claim 10, characterised in that the width of said curvilinear section (12) is less than or equal to 5 Lr.