Brake disc provided with a plurality of aerodynamic elements for developing a ventilation effect

Abstract

A brake disc (1) for a motor-vehicle disc brake device comprises a central hub body (2) and an external circumferential body (3) which are mechanically connected by means of a plurality of fastening members (4). The central hub body (2) comprises a plurality of aerodynamic elements (6, 9, 10) to uniformly convey an airflow, during the rotation of the disc, in order to effectively convey a flow of air to cool the disc (1) and to effectively dissipate the heat generated by the interference between the brake pads and the disc braking surfaces. The central hub body (2) and the aerodynamic elements (6, 9, 10) are formed in a single piece by means of additive manufacturing technology.

Description

[0001] Brake disc provided with a plurality of aerodynamic elements for developing a ventilation effect

[0002] TEXT OF THE DESCRIPTION

[0003] Field of the Invention

[0004] The present invention refers to brake discs for motor-vehicle disc brake devices, of the kind having a central hub body connectable to a motorvehicle wheel, and an external circumferential body encircling the central hub body, forming a wall with two opposite faces defining two disc braking surfaces adapted to be engaged by a brake calliper.

[0005] Known Art

[0006] Conventional brake discs are generally solid wall discs, or they may be so-called ventilated discs, having the external circumferential body of the disc formed with inner ventilation cavities, which communicate with a plurality of openings formed on the disc braking surfaces.

[0007] Ventilated discs are obtained by casting, by means of a relatively complex and costly method, since for the fusion casting it is necessary to use a mould comprising two chills and at least one internal core, in order to define the inner cavities of the disc.

[0008] A further known solution of a ventilated disc is described in document EP 3 495 684 B1. In this solution, the disc comprises an intermediate circumferential portion which is radially interposed between the hub and the external circumferential portion and the faces whereof define the disc braking surfaces. At such intermediate circumferential portion a plurality of radial blades are obtained by casting; in operation, during the rotation of the disc, they act as a disc ventilation rotor.

[0009] However, even said solution is not perfectly satisfactory, especially from the point of view of its complexity and production costs.

[0010] Object of the Invention

[0011] Generally speaking, an object of the present invention consists in providing a brake disc for a motor-vehicle disc brake device, provided with a solution for ventilating the disc which has a particularly simple and economical structure.

[0012] A further object of the invention is to provide a ventilated brake disc which is adapted to ensure a significant improvement, with respect to the known solution, as regards the ventilation efficiency.

[0013] A further object of the invention is to provide a modular brake disc, which may easily use the same ventilation features with discs of different sizes and materials, or vice versa.

[0014] Summary of the Invention

[0015] One or more of the aforementioned objects, as well as further objects which will become clearer in the following, are achieved according to the present invention by means of a brake disc having the features provided in the claims 1-15.

[0016] Further objects are achieved, according to the present invention, by means of a method for assembling a brake disc having the features provided in claim 16.

[0017] The claims are an integral part of the technical teaching provided herein in relation to the invention.

[0018] Description of the Drawings

[0019] Further objects, features and advantages of the present invention will become apparent from the detailed description provided in the following, which is made with reference to the annexed schematic drawings which are provided by way of non-limiting example only and wherein:

[0020] - Figure 1 is a perspective view of a brake disc according to possible embodiments;

[0021] - Figure 2 is a front view in an enlarged scale of some components shown in the previous Figure;

[0022] - Figure 3 is a sectional view of the brake disc shown in Figure 1 , along the line Ill-Ill shown in Figure 1 ; and

[0023] - Figure 4 is a perspective view of one of the features of the disc shown in Figures 1 , 2.

[0024] Detailed Description of a Plurality of Embodiments

[0025] In the following description, numerous specific details are shown in order to offer a thorough understanding of examples of one or more embodiments. The embodiments may be implemented without one or more of the specific details, or with other methods, components, materials, etc.

[0026] In other cases, well-known structures, materials or operations are not shown or described in detail in order not to obscure various aspects of the embodiments. The reference to “an embodiment” or to “one embodiment” throughout this description indicates that a particular configuration, structure or characteristic described in relation to the embodiment is comprised in at least one embodiment.

[0027] Therefore, phrases such as “in an embodiment” or “in one embodiment” which may be present in various points of the present description are not necessarily referred to one and the same embodiment.

[0028] Moreover, particular configurations, structures or characteristics may be suitably combined in one or more embodiments, and / or may be associated with the embodiments in a fashion other than illustrated herein, so that for example a feature exemplified herein in relation to a Figure may be applied to one or more embodiments illustrated in another Figure.

[0029] The references illustrated herein are for convenience only, and therefore do not limit the protection scope or the extent of the embodiments.

[0030] Initially referring to Figure 1 , reference 1 generally denotes a brake disc for a motor-vehicle disc brake device. The brake disc 1 comprises a central hub body 2, normally referred to as driving hub, which may be connected to the vehicle wheel. The brake disc 1 moreover comprises an external circumferential body 3 encircling the central hub 2, which is normally referred to as braking surface. The external circumferential body 3 forms a substantially flat surface which defines, with the two opposite faces thereof, two annular-crown shaped surfaces, which constitute the braking surfaces of the disc 1 . The braking surfaces may cooperate with a brake calliper (not shown) of any known type, provided with brake pads adapted to be pressed by a respective actuator against the two opposite faces of the braking surface, in order to slow down the rotation of the disc 1 during a braking step of the vehicle. In other words, the two flat annular faces of the external circumferential element 3 cooperate with the brake pads to implement the braking effect on the vehicle.

[0031] The brake disc 1 is implemented in a two-piece configuration, wherein the central hub body 1 and the external circumferential body 3 are made as two separate elements, which are subsequently connected in an assembly step by means of a series of fastening devices 4 which are distributed along a respective interface area of the central hub body 2 and of the external circumferential body 3. More specifically, the external circumferential body 3 comprises an internal circumferential portion 3’, along which a series of fastening holes 7 is obtained; similarly, the central hub body 2 comprises a peripheral circumferential portion 2’ along which a series of fastening holes 8 is obtained. In the assembled configuration, specifically shown in Figures 1 , 3, each fastening member 4 axially engages a respective pair of holes 7, 8, so as as to rigidly connect the central hub body 2 and the external circumferential body 3 with each other.

[0032] According to a further feature, the central hub body 2 is formed in a single piece by means of additive manufacturing technology. “Additive manufacturing” indicates a method, known in the art, wherein an energy source, such as a laser beam or plasma, is used to selectively melt powder layers or threads of metal material or plastic material having various sizes, in order to form, layer by layer, a component of metal material or of plastic material. Such production technique is particularly suitable to form components having a particularly complex structure in a single manufacturing process.

[0033] The central hub body 2 formed in a single piece comprises - with reference to the final configuration installed on the vehicle - an annular wall 5 having an external face 5’ parallel to the faces of the external circumferential body 3, and a cylindrical wall 5” interposed between the external face 5’ and the peripheral circumferential portion 2’.

[0034] According to a further feature, the central hub body 2 formed in a single piece comprises a plurality of aerodynamic elements 6, 9, 10, adapted to uniformly convey an airflow, during the rotation of the disc, to effectively convey a flow of air to cool the disc 1 - specifically, the surfaces contacting the brake pads - and to effectively dissipate the heat generated by the interference between the brake pads and the disc braking surfaces.

[0035] In one or more embodiments, the aerodynamic elements comprise a plurality of aerodynamic fins 6 integrated in the central hub body 2 along the circumference thereof. More specifically, the fins 6 extend between the outer edge of the face 5’ and the peripheral circumferential portion 2’, alternately with the fastening holes 8.

[0036] Figure 2 is a view in enlarged scale of one of the aerodynamic fins 6 mentioned in the foregoing.

[0037] In one or more embodiments, each fin 6 comprises a body of symmetrical shape with respect to its central symmetry axis, which defines a central portion and two end portions. Referring to the final assembled configuration, each fin 6 comprises an external face 11 and an opposite internal face 12 (not visible from the outside). The external face 11 has a general substantially concave shape, wherein the central portion is lowered with respect to the two end portions. Each fin 6 may moreover comprise, on each end portion, a connection and reinforcement arm 13 having opposite ends protruding from the internal face 12, respectively connected to the cylindrical wall 5” and to the external face of the peripheral portion 2’. Each arm 13 may comprise a central part 13’ protruding from the external face 11 , so as to form an extended rib in relief on the respective end portion of the external face 11 . According to another preferred feature, as shown in Figure 4, each fin 6 comprises a plurality of internal appendages 14, distributed along the internal face 12, which act as a flow separator and a turbulence generator. Preferably, the internal appendages 14 have a hemispherical shape.

[0038] Thanks to the profile of the aerodynamic fins 6, as described in the foregoing, it is possible to achieve various significant advantages. First of all, the aerodynamic fins enable to effectively convey the surrounding air, in order to cool the disc during braking. Secondly, the symmetrical profile of the fins 6 offers the possibility to use the disc according to the invention indifferently either on a right wheel or on a left wheel of a motor-vehicle, without affecting the effectiveness of the cooling step. The fins are also useful to provide a structural stiffening of the disc.

[0039] As stated in the foregoing, the central hub body 2 made in a single piece comprises a plurality of aerodynamic elements 6, 9, 10 to uniformly convey an airflow, during the rotation of the disc, in order to effectively convey a flow of air to cool the disc 1 and to effectively dissipate the heat generated by the interference between the brake pads and the disc braking surfaces. According to a further feature, the aerodynamic elements 9 comprise a plurality of openings 9 obtained along the cylindrical wall 5” of the hub body 2. More specifically, each opening 9 is arranged on a part of the cylindrical wall 5”, in such a way as to be interposed between respective end portions of two adjacent fins 6. It will be appreciated, therefore, that the hub body thus formed comprises a cylindrical wall 5” having some parts covered by the fins, alternating with parts visible from the outside on which the openings 9 are respectively provided. Preferably, the openings 9 have a circular shape.

[0040] According to a further feature, the aerodynamic elements of the hub body 2 comprise further aerodynamic elements 10 obtained on the external face 5’ of the annular wall 5. In one or more embodiments, said further aerodynamic elements are through openings which enable cooling the central area of the disc and the external braking surface (thanks to a flow of air which is normally directed from the interior of the vehicle outwards). As shown, by way of non-limiting example only, in Figure 1 , on the external face 5’ a plurality of fastening holes are obtained to receive respective elements for the connection of the wheel. The external face 5’ may comprise a plurality of lowered seats 15 on which said further aerodynamic elements 10 are obtained, which can comprise ventilation slots 10’ and / or holes 10”. In a specific embodiment, on each lowered seat 15 there is obtained a main hole 10” interposed between two auxiliary slots 10’.

[0041] As stated in the foregoing, the brake disc 1 is implemented as a two- piece configuration, wherein the central hub body 2 and the external circumferential body 3 are configured as two separate elements, which are then connected by means of a plurality of fastening members 4. Advantageously, thanks to this feature, there is provided a “modular” brake disc 1 , wherein it is possible to use the same hub body, with the related aerodynamic features, in combination with external circumferential bodies which are different in size and material, or else to use the same external circumferential body and complement the disc with different hub bodies having different aerodynamic properties, depending on the expected flow of air in the vehicle dynamics. Moreover, such a modularity may be advantageously used during the maintenance of disc 1 , for example by replacing the outer circumferential body due to the wear of the braking surfaces, while keeping the same central hub body.

[0042] By producing the central hub body 2 by means of additive manufacturing technology, it is possible to integrate, into the hub body 2, aerodynamic elements having a particularly complex shape, which cannot be obtained with traditional manufacturing processes.

[0043] Of course, without prejudice to the principles of the inventions, the implementation details may amply vary with respect to what has been described and illustrated by way of non-limiting example only, without departing from the scope of the present invention as defined by the annexed claims.

Claims

CLAIMS1. Brake disc (1 ) for a motor-vehicle disc brake device, comprising:- a central hub body (2) connectable to a motor-vehicle wheel,- an external circumferential body (3) encircling the central hub body (2), forming a wall with two opposite faces defining two disc braking surfaces,- wherein said central hub body (2) and said external circumferential body (3) are two different pieces mechanically connected by means of a plurality of fastening members (4),- wherein the central hub body (2) comprises a plurality of aerodynamic elements (6,9,10) to uniformly convey an airflow, during the rotation of the disc, in order to effectively convey a flow of air to cool the disc(1 ) and effectively dissipate the heat generated by the interference between brake pads and the disc braking surfaces and the wheel bearing areas,- wherein the central hub body (2) and the aerodynamic elements (6,9,10) are formed in a single piece by means of additive manufacturing technology.

2. Brake disc (1 ) according to claim 1 , wherein the external circumferential body (3) comprises an internal circumferential portion (3') along which a first series of fastening holes (7) is obtained, wherein the central hub body (2) comprises a peripheral circumferential portion (2') along which a second series of fastening holes (8) is obtained, wherein each fastening member (4) axially engages a respective pair of holes (7, 8), so as to rigidly connect the central hub body (2) and the external circumferential body (3).

3. Brake disc (1 ) according to claim 2, wherein the central hub body(2) comprises an annular wall (5) having an external face (5') parallel to the faces of the external circumferential body (3), and a cylindrical wall (5") interposed between the external face (5') and the peripheral circumferential portion (2').

4. Brake disc (1 ) according to claim 3, wherein the aerodynamic elements (6,9,10) comprise a plurality of aerodynamic fins (6) extending between an outer edge of the face (5') and the peripheral circumferential portion (2'), alternately with the fastening holes (8) of the second series.

5. Brake disc (1 ) according to claim 4, wherein each fin (6) comprises a body of symmetrical shape with respect to its central symmetry axis, having a central portion and two end portions, wherein each fin (6) defines an external face (11 ) and an opposite internal face (12).

6. Brake disc (1 ) according to claim 5, wherein said external face (11 ) has a general shape substantially concave, wherein the central portion is lowered with respect to the end portions.

7. Brake disc (1 ) according to claim 5 or 6, wherein a plurality of internal appendages (14) is obtained on said internal face (12), distributed along the internal face (12).

8. Brake disc (1 ) according to any of claims 5-7, wherein each end portion of the fin (6) comprises a connection and reinforcement arm (13) having opposite ends protruding from the internal face (12) respectively connected to the cylindrical wall (5") and to an external face of the peripheral portion (2').

9. Brake disc (1 ) according to claim 8, wherein each arm (13) comprises a central part (13') protruding from the external face (11 ), so as to form an extended rib in relief on the respective end portion of the external face (11 ).

10. Brake disc (1 ) according to any of claims 4-9, wherein the aerodynamic elements (6,9,10) comprise a plurality of openings (9) obtained along the cylindrical wall (5").

11. Brake disc (1 ) according to claim 10, wherein each opening (9) is arranged on a part of the cylindrical wall (5"), and interposed between respective end portions of two adjacent fins (6), in such a way that the cylindrical wall (5") has some parts covered by the fins (6), alternating with other parts visible from the outside on which the openings (9) are provided.

12. Brake disc (1 ) according to any of claims 4-11 , wherein the aerodynamic elements (6,9,10) include further aerodynamic elements (10) obtained on the annular wall (5).

13. Brake disc (1 ) according to claim 12, wherein said further aerodynamic elements (10) include through openings enabling cooling of the disc (1 ) in correspondence with a central area thereof and the external circumferential body (3).

14. Brake disc (1 ) according to claim 13, wherein the external face(5') of the annular wall (5) includes a plurality of lowered seats (15) on which said further aerodynamic elements (10) are obtained.

15. Brake disc (1 ) according to claim 14, wherein said further aerodynamic elements (10) comprise a main hole (10") placed between two auxiliary slots (10').

16. Method for manufacturing a brake disc (1 ) according to any of the previous claims, comprising:- providing said central hub body (2) and said aerodynamic elements (6,9,10) in a single piece using additive manufacturing technology, - assembling the central hub body (2) to the external circumferential body (3) using a plurality of fastening members (4).

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