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: Gregory REGAZZONI, 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 noted, however, that such coupling systems are often made in such a way as to negatively affect the cooling flows due to the their conformation and / or positioning in relation to the ventilation ducts. It is in fact known that to maximize the heat extracted from the brake disc, it is important that the 5 air flow inside the ventilation channels so as to ensure leaks of load as small as possible, and in order to maximize the capacity of the cooling airflow, which heats up and exits from the radially outer edge of the rotating disc brake braking band. The Applicant therefore set itself the problem of creating a brake disc that improves the 10 coupling area between the bell and the braking band and which at the same time allows to optimize the ventilation of the brake disc. 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 braking and the bell extending around a common axis of rotation; the band 15 braking system featuring lateral braking surfaces capable of cooperating with a relative caliper brake exerting a braking action on the vehicle on which the disc is installed brake; the lateral surfaces also defining a plurality of ventilation channels arranged away from the axis of rotation, interspersed with a plurality of ribs arranged away from the axis of rotation, equipped with suitable side walls 20 to define the side walls of the said ventilation channels; each ventilation channel extending along a direction of extension between an air opening radially internal and a radially external air opening; - said braking band being provided with a continuous flat internal ring equipped with a median plane and two lateral faces, on at least one of which there is a plurality 25 of tower elements; each tower element being arranged in correspondence with a radial opening inside of a ventilation channel, so as to overlap in the direction circumferential completely to said radially internal opening and for more than 50% of their circumferential extension to a first and a second rib arranged 30 adjacent to said radially internal opening. The Applicant believes that the presence of an opening located directly behind a tower element, which allows on the one hand to increase the overall number of ventilation channels present on the brake disc and on the other to increase the cross-section of entrance and consequently the flow rate of the ventilation channels adjacent to the element 5 tower and placed in circumferential direction directly before and after the latter The applicant has thus obtained a new optimization of the connection between the bell and braking band, which allows to improve the path of the cooling air in entrance to the ventilation channels increasing the flow of cooling air 10 within the channels themselves. 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. By “radial direction” is meant a direction substantially orthogonal to the 15 axial direction. By “tangential or circumferential direction” is meant an orthogonal direction either both in the axial and radial directions. For “arranged on the extension” refers to the positioning of a first element with respect to a second element, it is understood as the condition in which the direction of 20 prevalent extension of a first element, such as the lateral wall of a canal ventilation, is arranged with respect to the direction of extension of a second element, such as the first side wall of a tower element, so that the two directions are coincident or differ by an angle, between them, equal to maximum at 10°. 25 The present invention, in one or more preferential aspects, may comprise one or more of the characteristics listed below. Conveniently the aforementioned tower element is arranged so as to overlap in circumferential direction completely to the aforementioned first and second rib for at least 85% of their circumferential extension. 30 Preferably, the aforementioned tower element comprises a first side wall substantially rectilinear arranged on the extension of a lateral wall of the first rib and a second substantially rectilinear lateral wall arranged on the extension of a lateral wall of the second rib. Conveniently, the aforementioned tower element may comprise a side wall 5 curvilinear arranged to connect the first and second side walls substantially rectilinear, the curved side wall faces the axis of rotation. Preferably, the curved side wall has a radius of curvature greater than or equal to 5 mm. Advantageously, the tower element extends in a direction parallel to the axis 10 rotation of the brake disc from one of the two lateral faces for a height less than or equal to 35 mm. Conveniently, the aforementioned tower element extends in one direction inclined or coincident with respect to the radial direction by a principal plane containing the the aforementioned radially internal opening is maximum 40 mm. 15 Preferably, the aforementioned radially internal opening arranged at each tower element extends in a direction parallel to the axis of rotation of the brake disc for a height less than or equal to 18 mm. Advantageously, the radially internal opening arranged circumferentially subsequently to the one corresponding to the aforementioned tower element extends 20 according to a direction parallel to the axis of rotation of the brake disc from one of the two lateral faces for a height less than or equal to 30 mm and greater than or equal to 5 mm. Preferably, the radially internal opening arranged at each tower element has an area greater than or equal to 25 mm. Conveniently, each circumferentially consecutive internal opening and 25 previous to the one placed in correspondence with each tower element has an area less than or equal to 500 mm. Preferably, each internal opening arranged at each tower element has an area less than or equal to 0.9 of the area of ​​the internal opening arranged in a circumferential direction. 30 Advantageously, the tower elements are made in one piece with the first and the second rib. Conveniently two adjacent tower elements can be placed one after the other at a distance, measured at two corresponding points, greater than or equal to 20 mm. 5 Preferably there may be eight to fourteen tower elements per disc brake. 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. 10 Brief description of the drawings 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; 15 - Figure 2 is a side sectional view of a portion of the braking band of figure 1; - figure 3 is a schematic cross-sectional view of the braking band taken according to the section plane EE of figure 2; - Figure 4 is an enlarged perspective schematic view of the portion of the 20 brake disc at a tower member according to the present invention; and - Figure 5 is an enlarged schematic plan and section view of a portion of the brake disc at a tower element according to the present invention. Detailed description of embodiments of the invention 25 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 30 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. 5 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 plurality of ventilation channels 5 arranged away from the rotation axis X- 10 X and interspersed with a plurality of ribs 15 also arranged in distance from the rotation axis XX. Each rib 15 has, in plan, a width L and side walls of 15'15'' arranged so as to define the side walls 5',5'' of the aforementioned ventilation channels 5. The side walls 15'15'' of the aforementioned ribs 15 extend away 15 from the axis of rotation XX for the entire extension of the ventilation channels 5. Preferably, the ribs 15 do not have a constant width along the plan their direction of extension, but a width that increases away from the axis of rotation XX. By width of a rib 15 is meant a dimension of the rib 15, 20 essentially orthogonal to the direction of extension of the rib itself. The ventilation channels 5 extend away from the axis of rotation XX according to an extension direction, between a radially internal air opening 6, facing the rotation axis XX, and a radially external air opening 7, arranged in correspondence with the radially external edge of the braking band 3. 25 Preferably, the ventilation ducts 5 do not have a constant cross-section, along their direction of extension, but a cross-section that increases in moving away from the axis of rotation XX. By cross-section of a ventilation duct 5 is meant a section of the duct of ventilation 5, substantially, orthogonal to the direction of extension of the channel 30 ventilation 5 same. The 5',5'' side walls of the ventilation channels 5, in plan are directed substantially in accordance with the direction of extension of the ventilation duct or slightly inclined with respect to it. The side walls 5',5'' of the ventilation channels 5 are coincident with the side walls 5 15',15'' of the ribs 15, in other terms as previously mentioned the walls lateral 15',15''of the ribs 15 define and coincide with the lateral walls' 5',5'' of ventilation channels 5. In the embodiment shown in the figures, each ventilation channel 5 In plan it presents a trend provided with a straight section 11 and a section 10 curvilinear 12 arranged consecutively to the straight section 11, but they could present a different trend, for example substantially rectilinear along the entire extension of the same ventilation channel 5, without going beyond the scope of protection of this invention. Always with reference to the embodiment shown in the figures, the trait 15 straight 11 extends from the radially internal opening 6 and exhibiting extension greater than the curved section 12, the latter as visible in figure 3 flows in the radially external air opening 7. Always with reference to the embodiment shown in the figures, the trait straight line 11 of the ventilation channel 5 has a preponderant extension compared to 20 to the curved section 12 and in general with respect to the total extension of the canal ventilation 5 same. Preferably, the straight section 11 has an extension greater than or equal to the 60% 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. 25 Even more preferably, the straight section 11 has an extension greater than or equal to 70% of the overall extension of the ventilation duct 5. Preferably, the straight section 11 has an inclined path with respect to the radial direction so as to form an inclination angle α greater than or equal to at 45°. Preferably, each radially internal opening 6 has a larger area equal to 36 mm. As will be described in more detail below, not all openings 6 radially internal they have the same area. 5 With reference to the embodiment shown in the figures, in the direction circumferential two radially internal openings 6, circumferentially consecutive, they are interspersed with a radially internal opening 6 with a reduced area. The reduction of the reduced area in this radially internal opening 6 is due to the particular conformation of a tower element 13, described below, arranged in 10 correspondence of, in particular in front of, such radially internal opening 6. Each radially internal opening 6 circumferentially consecutive and preceding to the one located in correspondence with the tower element 13, that is to say the one which presents a reduced area, instead presents an area that is not reduced, but still smaller than o equal to 500 mm. 15 The radially internal opening 6 is arranged in correspondence with each tower element 13, that is, the one with the smallest area, has an area less than 0.9 of the area of the radially internal opening 6 circumferentially consecutive. The same thing applies to the radially internal air opening 6 preceding the one located in correspondence of each tower element 13. 20 The radially internal opening 6 is arranged in correspondence with each tower element 13 extends in a direction parallel to the rotation axis XX of the brake disc 1 for a height H less than or equal to 18 mm. The height of such radially internal opening 6 is measured from a top surface of the tower element 13. 25 The radially internal opening 6 is arranged circumferentially consecutively or previously to the one corresponding to the aforementioned element tower 13 has a height H less than or equal to 30 mm and greater than or equal to 5 mm measured in a direction parallel to the rotation axis XX. Each radially external opening 7 has an area greater than or equal to the area 30 of the radially internal opening 6. The radially external openings 7 can all have the same area. The brake disc 1 also comprises a bell 2, suitable for being operationally 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 5 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. The inner ring 10 may have at least one tower element 13 which develops substantially orthogonally to the median plane MM starting from a face 10 side 8 of the inner ring 10. With reference to figures 2 and 3 and in accordance with the preferred embodiment, the inner ring 10 features not just one, but a plurality of tower elements 13 distributed along a coupling circumference 20 concentric to the central axis of rotation XX. 15 The tower elements 13 provide a seat 27 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. The tower elements 13 are spaced angularly, preferably in a constant manner along the mating circumference 20. 20 Preferably, the tower elements 13 are placed at a distance from each other, measured at two corresponding points on two tower elements 13 adjacent, greater than or equal to 20 mm, preferably greater than or equal to 40 mm. The tower elements 13 are placed at a distance from each other, measured in 25 correspondence of two corresponding points on two adjacent tower elements 13, minor of or equal to 80 mm. Preferably, there are eight to fourteen tower elements 13 per brake disc 1, even more preferably there are nine to thirteen tower elements 13 per disk brake 1. Advantageously, each tower element 13 extends in one direction parallel to the axis of rotation XX from one of the two lateral faces 8,9 for a height less than or equal to 35mm. Each tower element 13 is arranged in correspondence with a radially opening 5 internal 6 of a ventilation channel 5, so as to overlap in the direction circumferential completely to such radially internal opening 6 and to overlap to a first and a second rib 15 arranged radially adjacent to this opening internal for more than 50% of their circumferential extension. In other words, each tower element 13 is completely overlapped by an opening 10 radially internal 6 and predominantly, almost completely, at two ribs 18, called first and second, adjacent to the aforementioned radially internal opening 6. Preferably, each tower element 13 is arranged so as to overlap in circumferential direction to the first and second rib for at least 85% of the 15 their circumferential extension. In the embodiment shown in the figures, two consecutive ribs 15 in circumferential direction, so-called first and second rib, are joined together by a tower element 13 which presents substantially the same shape throughout its extension height, thereby reducing the entrance area of ​​the radially internal opening 6 20 placed in a radial direction behind the tower element 13 itself. The two radially internal openings 6 adjacent in the circumferential direction to the one at reduced entrance area do not however present a reduction in cross-section. As a result, each radially internal opening 6 is arranged correspondingly of each tower element 13 has an area less than 0.9 of the area of ​​the opening 25 radially internal next and previous circumferentially. In the following we will describe a tower element 13, its shape and arrangement with respect to three radially internal openings 6, consecutive in the circumferential direction and interspersed with two ribs 15, called first and second rib, such as shown in figure 4, it being understood that the above applies to all remaining elements 30 to tower 13. Each tower element 13 comprises a first side wall substantially straight line 16 arranged on the extension of a lateral wall 15' of the first rib and a second lateral wall 17 substantially rectilinear arranged on the extension of a 15'' side wall of the second rib. 5 As better visible in figure 3, the first 16 and the second 17 side walls substantially rectilinear, they are joined and connected to each other by a side wall curvilinear 18 that faces the rotation axis XX. The curved side wall 18 has a radius of curvature R greater than or equal to at 5 mm. 10 Each tower element 13 has an elongated shape in plan according to a direction capable of forming an inclination angle β with a radial direction. As visible in figure 3, each tower element 13 extends in this direction from a main floor containing predominantly, that is to say at least 50% of its extension, the radially internal opening 6. 15 Preferably, in this direction each tower element 13 extends to a maximum of 40 mm. According to an alternative embodiment, each tower element 13 has in plant an elongated shape in a direction coinciding with a radial direction. Each tower element 13 extends in this direction from a main floor 20 predominantly contained, that is to say for at least 50% of its extension, the radially internal opening 6. Preferably, in this direction each tower element 13 extends to a maximum of 40 mm. Preferably, the tower elements 13 are made in one piece with the plate 25 braking 3. Advantageously all the tower elements 13 of the same brake disc are the same for shape and size. Thanks to the features described above, provided separately or in combination, it is possible to provide a solution to the needs of the coupling area between the bell 30 and braking band and obtain the above advantages, in particular: -better cooling efficiency of the brake band 3 and the disc is allowed brake 1 compared to known solutions; -the path of the cooling air entering the ventilation channels is optimised in order to increase the flow of cooling air inside the channels themselves; 5 - mechanical and thermomechanical stresses on the braking surfaces are reduced of the braking band; -the life of the disc is increased in terms of vehicle mileage, in particular for applications on high-performance vehicles, such as racing cars. Various modifications may be made to the embodiments described in the 10 detail, while remaining within the scope of protection of the invention, defined by the following claims.

Claims

1. Brake disc (1) comprising a bell (2) and a braking band (3) radially external to the latter, said band (3) and said bell (2) extending around a common axis of rotation (XX); said braking band (3) having lateral braking surfaces (4) designed to cooperate with a relative brake caliper to exert a braking action on the vehicle on which said brake disc (1) is installed; said lateral surfaces (4) also defining a plurality of ventilation channels (5) arranged away from the axis of rotation (XX), interspersed with a plurality of ribs (15) arranged away from the axis of rotation (XX) and equipped with lateral walls (15',15'') designed to define, in plan view, the lateral walls (5',5'') of said ventilation channels (5); each ventilation channel (5) extending along a direction of extension between a radially internal air opening (6) and a radially external air opening (7);said braking band (3) being provided with a continuous flat internal ring (10) having a median plane (MM) and two lateral faces (8-9), on at least one of which there is a plurality of tower elements (13); each tower element (13) being arranged in correspondence with a radially internal opening (6) of a ventilation channel (5), so as to completely overlap in the circumferential direction with said radially internal opening (6) and with a first and a second rib (15), arranged adjacent to said radially internal opening (6), for more than 50% of their extension in the circumferential direction.; 2. Brake disc (1) according to claim 1, characterised in that said tower element (13) is arranged so as to overlap in a circumferential direction with said first and second rib (15) for at least 85% of their extension in a circumferential direction.

3. Brake disc (1) according to claim 1 or 2, characterised in that said tower element (13) comprises a first substantially rectilinear side wall (16) arranged on the extension of a side wall (15') of said first rib and a second substantially rectilinear side wall (17) arranged on the extension of a side wall (15'') of said second rib (15).

4. Brake disc (1) according to claim 3, characterised in that said tower element (13) comprises a curvilinear side wall (18) arranged to connect said first (16) and said second (17) substantially rectilinear side walls, said substantially curvilinear side wall (18) facing said axis of rotation (XX).

5. Brake disc (1) according to any of claims 1 to 4, characterised in that said tower element (13) extends in a direction parallel to said axis of rotation (XX) from one of the two lateral faces (8-9) for a height less than or equal to 35 mm.

6. Brake disc (1) according to any of claims 1 to 5, characterised in that said tower element (13) extends in a direction inclined or coinciding with the radial direction from a main plane containing said radially internal opening (6) for a maximum of 40 mm.

7. Brake disc (1) according to any of claims 1 to 6, characterised in that said radially internal opening (6) arranged in correspondence with each tower element (13) extends in a direction parallel to the axis of rotation of the brake disc (1) for a height (H) less than or equal to 18 mm.

8. Brake disc (1) according to any of claims 1 to 7, characterised in that said radially internal opening (6) arranged circumferentially subsequent to the one corresponding to said tower element (13) extends in a direction parallel to the axis of rotation (XX) of the brake disc (1) from one of the two lateral faces (8-9) for a height (H) less than or equal to 30 mm and greater than or equal to 5 mm.

9. Brake disc (1) according to any of claims 1 to 8, characterised in that said radially internal opening (6) arranged in correspondence with each tower element (13) has an area greater than or equal to 25mm2.

10. Brake disc (1) according to any of claims 1 to 9, characterised in that each radially internal opening circumferentially consecutive to the one arranged in correspondence with the tower element (13) has an area less than or equal to 500mm2.

11. Brake disc (1) according to any of claims 1 to 10 characterised in that said radially internal opening (6) arranged at 5 correspondence with each tower element (13) has an area less than 0.9 of the area of ​​the next or previous internal opening in the circumferential direction.

12. Brake disc (1) according to any of the preceding claims 1 to 11, characterised in that said tower elements (13) are made in a single piece 10 with said first and second rib (18).