"Brake disc" DESCRIPTION

[0001]. Field,of the invention

[0002]. The present invention relates to braking devices comprising brake discs suited to vehicles.

[0003]. In particular, the present invention relates to a brake disc comprising a bell and a braking band coupled together with a toothing.

[0004]. Background art

[0005]. In a disc brake, the brake caliper is generally arranged straddling the outer peripheral margin of a brake disc, adapted to rotate about a rotation axis (A-A) defining an axial direction (X- X). In a disc brake, a radial direction (R-R), substantially orthogonal to said axial direction (X-X), and a tangential (C-C) or circumferential (C-C) direction, orthogonal to both said axial direction (X-X) and said radial direction (R-R), are further defined.

[0006]. Brake calipers are constrained to a support structure, which remains stationary with respect to the vehicle wheel, such as a stub axle of a vehicle suspension or a vehicle wheel hub or a fork, for example. The brake caliper usually comprises a caliper body having two elongated portions arranged so as to face opposite braking surfaces of a brake disc, and at least one bridge connecting said two elongated portions together. Suitably actuated calipers press the pads against the braking band and the braking action is produced by the friction between the pads and the braking band of the brake disc.

[0007]. Brake discs are known, in which the bell is made of a different material from that of the braking band, and in particular bells made of a deformed and cup-shaped steel sheet and provided with a circumferential toothing to be coupled to the braking band.

[0008]. Such brake discs, which can be referred to as composite, allow a lower weight, for example, and thus help reduce the weight of the unsprung masses of the related vehicle.

[0009]. A brake disc of this type is known, for example, from DE102009012217 and EP2850333A1.

[0010]. Other similar solutions are known from DE102009012216,

US2014000995, US2014311838, EP2404075A1, DE102012022775A1.

[0011]. In this case, the braking band and the bell each have teeth, these teeth being in mutual engagement to allow the torque transmission between the braking band and the bell. To also ensure the axial attachment between the braking band and the bell, the bell has retaining elements which are directed radially outwards on an upper edge and rest against a corresponding surface of the braking band.

[0012]. Preferably, the braking bands are ventilated in order to dissipate the heat developed during the braking action.

[0013]. The drawback of such a solution is that such an axial attachment between the braking band and the bell occurs at one of the two plates of the braking band.

[0014]. In particular, the braking band toothing is made on the lower edge of the braking band plate facing the vehicle wheel so as to minimize the axial extension of the tubular portion of the bell and facilitate the ingress of cooling air from the central opening of the braking band.

[0015]. However, these known solutions have a non-ideal mass distribution to resist and minimize the thermal distortions generated by the heating of the braking band. Indeed, the constraint of the bell to the plate facing the wheel leads to a dissymmetric thermal expansion of the braking band, which, in the case of high overheating, results in a significant departure from the ideal braking plane of the braking surfaces delimiting the exterior of the plates.

[0016]. Solution

[0017]. Therefore, it is the object of the present invention to provide a disc brake disc having a toothed connection between a bell and a braking band and minimizing the axial mass distribution of the connection portion displaced with respect to the centerline plane of the braking band, thus reducing the thermal distortions of the brake disc.

[0018]. This and other objects and advantages are achieved by a brake disc according to claim 1.

[0019]. Some advantageous embodiments are the subject of the dependent claims.

[0020]. The analysis of this solution showed how the suggested solution allows obtaining a brake disc in which the non-ideal mass distribution is minimized in order to resist and minimize the thermal distortions generated by the heating of the braking band without simultaneously compromising the ventilation and especially a heat exchange between the braking band and the cooling air.

[0021]. Drawings

[0022]. Further features and advantages of the device, the disc brake, and the vehicle will become apparent from the following description of preferred embodiments thereof, given by way of nonlimiting indication, with reference to the accompanying drawings, in which:

[0023]. - figure 1 shows an axonometric view of a brake disc from the wheel side;

[0024]. - figure 2 is an axonometric view of the disc in figure 1 from the vehicle side;

[0025]. - figure 3 shows an axonometric view with parts separated of the braking band and the disc bell in figure 1 from the wheel side;

[0026]. - figure 4 is an axonometric view of a detail of the braking band in figure 3;

[0027]. - figure 5 is an axonometric view of a detail of the bell in figure 3;

[0028]. - figure 6 shows an axonometric view with parts separated of the braking band and the disc bell in figure 1 from the vehicle side;

[0029]. - figure 7 is an axonometric view of a detail of the braking band in figure 6;

[0030]. - figure 8 shows a detail of a section view in a radial and axial plane of the disc in figure 1;

[0031]. - figure 9 is an enlargement of the coupling between the bell and the braking band in the section view in figure 8.

[0032]. Description of some preferred embodiments

[0033]. According to a general embodiment, a disc brake 1 comprises a braking band 2. The bell 2 comprises a bell base 3, e.g., disc-shaped, and a tubular wall 4. The tubular wall 4 protrudes axially A-A from said bell base 3.

[0034]. Said brake disc 1 further comprises a braking band 5 centrally having a band opening 6.

[0035]. The tubular wall 4 of said bell 2 comprises a cup toothing system 7 extending along a circumference outside said tubular wall 4. Said cup toothing 7 comprises cup teeth 8 protruding outwards in the radial direction R-R.

[0036]. According to an embodiment, the tubular wall 4 of said bell 2 forms in one piece a cup toothing system 7 extending along a circumference outside said tubular wall 4 and comprising cup teeth 8 protruding outwards in a radial direction R-R.

[0037]. Said cup teeth 8 are circumferentially C-C spaced out by an empty cup gap 9, where each empty cup gap 9 is in the circumferential direction C-C between adjacent cup teeth 8.

[0038]. The braking band 5 further comprises a ring toothing system 10 having an annular ring body 11 from which ring teeth 12 radially inwardly protruding at the band opening 6 extend.

[0039]. According to an embodiment, the braking band 5 forms in one piece a ring toothing system 10 having an annular ring body 11 from which ring teeth 12 radially inwardly protruding at the band opening 6 extend.

[0040]. Said ring teeth 12 are circumferentially C-C spaced out by a ring tooth gap 13, where each ring tooth gap 13 is in the circumferential direction C-C between ring teeth 12.

[0041]. The cup toothing system 7 and the ring toothing system 10 mutually mesh.

[0042]. According to an embodiment, the cup toothing system 7 and the ring toothing system 10 mutually mesh and are intimately coupled together.

[0043]. Said braking band 5 is a ventilated braking band comprising a first wheel-side band plate 14 and a second vehicleside band plate 15 mutually facing and spaced apart by a ventilation duct 16 and mutually connected by plate connecting elements 17.

[0044]. Advantageously, said annular ring body 11 of said ring toothing system 10 at least partially faces said ventilation duct 16 forming at least one annular channel 18 at the base of said first or second plate 14, 15 delimited by said tubular wall 4 of said bell 2 at least on one side thereof.

[0045]. According to an embodiment, said annular ring body 11 is a single body which is continuous in the circumferential direction C- C.

[0046]. According to an embodiment, said annular ring body 11 is connected to one of said first or second plate 14, 15 by at least one inclined connecting element 19 forming said annular channel 18 at the base of said first or second plate 14, 15.

[0047]. According to an embodiment, said annular ring body 11 is a single body which is continuous in the circumferential direction C- C.

[0048]. Said annular ring body 11 is connected to one of said first or second plate 14, 15 by at least one inclined connecting element 19 forming said annular channel 18 at the base of said first or second plate 14, 15.

[0049]. According to an embodiment, said annular ring body 11 is connected to one of said first or second plates 14, 15 by at least one circumferentially continuous inclined connecting element 19.

[0050]. According to an embodiment, said annular ring body 11 comprises a flared ring wall 21 facing said tubular wall 4 of said bell 2.

[0051]. According to an embodiment, said annular ring body 11 comprises a flared ring wall 21 facing said tubular wall 4 of said bell 2 and where said flared ring wall 21 is frustoconical in shape.

[0052]. According to an embodiment, said annular ring body 11 is discontinuously connected to an opposite plate 15, 14 with respect to said first or second plate 14, 15.

[0053]. According to an embodiment, said annular ring body 11 is discontinuously connected to an opposite plate 15, 14 with respect to said first or second plate 14, 15 by a plurality of ring column elements 20 mainly extending in the axial direction A-A.

[0054]. According to an embodiment, said annular ring body 11 is discontinuously connected to an opposite plate 15, 14 with respect to said first or second plate 14, 15 by a plurality of ring column elements 20 mainly extending in the axial direction A-A, where each ring column element connects close to the inner radial end of said opposite plate 15, 14 remaining within said ventilation duct 16.

[0055]. According to an embodiment, said annular ring body 11 is discontinuously connected to an opposite plate 15, 14 with respect to said first or second plate 14, 15 by a plurality of ring column elements 20 mainly extending in the axial direction A-A and where said ring column elements 20 are enlarged at the ends thereof and tapered towards a smaller portion located between said ends.

[0056]. According to an embodiment, said annular ring body 11 is discontinuously connected to an opposite plate 15, 14 with respect to said first or second plate 14, 15 by a plurality of ring column elements 20 mainly extending in the axial direction A-A and where ventilation openings 22 are formed between the ring column elements 20, which put said band opening 6 in communication with said ventilation duct 16.

[0057]. According to an embodiment, at least one of said cup teeth 8 or at least one tubular wall portion 4 of said bell 2 delimiting said empty cup gap 9 comprises at least one radial cup deformation 23 or radial and circumferential cup deformations 24 forming at least one axial abutment 25 which delimits, at least in one direction, the displacement in the axial direction A-A of at least one ring tooth 12.

[0058]. According to an embodiment, at least one of said cup teeth 8 or at least one tubular wall portion 4 of said bell 2 delimiting said empty cup gap 9 comprises at least one pair of radial cup deformations 23 or radial and circumferential cup deformations 24 forming at least two opposing axial abutments 25 which delimit, in opposite directions, the displacement in the axial direction A-A of at least one ring tooth 12.

[0059]. According to an embodiment, said bell 2 is obtained from at least one deformed and shaped sheet metal.

[0060]. In order to meet specific, contingent needs, those skilled in the art may make several changes and adaptations to the abovedescribed embodiments and may replace elements with others which are functionally equivalent, without however departing from the scope of the following claims.

LIST OF REFERENCE SIGNS

1 brake disc

2 bell

3 bell base

4 tubular wall

5 braking band

6 band opening

7 cup toothing system

8 cup teeth

9 empty cup gap

10 ring toothing system

11 annular ring body

12 ring teeth

13 ring tooth space

14 first wheel-side band plate

15 second vehicle-side band plate

16 ventilation duct

17 plate connecting elements

18 annular canal

19 inclined connecting element

20 ring column element

21 flared ring wall

22 ventilation openings

23 radial cup deformations

24 radial and circumferential cup deformations

25 axial abutment

26 axial abutment

A-A axial direction

R-R radial direction

C-C circumferential direction

X-X disc axis of disc brake