Brake disc for a bicycle

Abstract

A bicycle brake disc having a braking track with brake pads and a plurality of first connection portions that extend towards the inside and that comprise respective first connection areas; a second component having (i) a radially inner annular coupling portion for coupling with a hub of a wheel of the bicycle and (ii) a plurality of second connection portions. The second connection portions extending outwards from the radially inner annular coupling portion towards the first component and comprising respective second connection areas; connecting members active between the first connection areas and the corresponding second connection areas. The second connection portions comprise at least one respective pair of arms that extend between the respective second connection area and the radially inner annular coupling portion, the pair of arms defining a through opening between them.

Claims

1. A brake disc for a bicycle comprising: a first component having a braking track configured to cooperate with brake pads and a plurality of first connection portions that extend towards the inside and that comprise respective first connection areas; a second component having (i) a radially inner annular coupling portion for coupling with a hub of a wheel of the bicycle and (ii) a plurality of second connection portions, in a number corresponding to said plurality of said first connection portions, the second connection portions extending outwards from the radially inner annular coupling portion towards said first component and comprising respective second connection areas; and connecting members active between the first connection areas and the corresponding second connection areas; wherein said second connection portions comprise at least one respective pair of arms that extend between the respective second connection areas and the radially inner annular coupling portion, said pair of arms defining a through opening between them, wherein said first connection area axially overlaps the corresponding second connection area and is housed in a recess of the second connection area.

2. The brake disc according to claim 1, wherein said pair of arms has a divergent arrangement from the respective second connection area towards the radially inner annular coupling portion.

3. The brake disc according to claim 1, wherein each second connection portion comprises a reinforcing arm that extends from the respective second connection area and reaches another second connection portion that is arranged circumferentially adjacent to said another second connection portion.

4. The brake disc according to claim 3, wherein said reinforcing arm reaches an arm of said pair of arms of a subsequent second connection portion at or close to a radially outer end thereof.

5. The brake disc according to claim 1, wherein each first connection portion comprises a radially outer end joined to the braking track and a radially inner end at the respective first connection area, said first connection portion extending in an inclined direction with respect to a radial direction passing through the center of the radially inner annular coupling portion and through said radially inner end.

6. The brake disc according to claim 1, wherein each arm of said pair of arms has a same axial thickness.

7. The brake disc according to claim 3, wherein said reinforcing arm has a lower axial thickness than an axial thickness of said pair of arms.

8. The brake disc according to claim 1, wherein said connecting members comprise perforated rivets axially received in respective through holes defined in said first connection area and in said second connection area.

9. The brake disc according to claim 1 wherein said connecting members are equally spaced from one another by a distance (L) comprised in a range between 10 mm and 80 mm, including extreme values.

10. The brake disc according to claim 1, wherein said connecting members are equally spaced from one another by a distance (L) comprised in a range between 20 mm and 50 mm, including extreme values.

11. The brake disc according to claim 1, wherein said connecting members are equally spaced from one another by a distance (L) comprised in a range between 35 mm and 40 mm, including extreme values.

12. The brake disc according to claim 1, wherein said first connection area has exclusively axial contact with the second connection area.

13. The brake disc according to claim 1, wherein said braking track comprises a plurality of through slits, of elongated shape and inclined with respect to a direction of extension of a side edge of said brake pads.

14. The brake disc according to claim 13, wherein said through slits have an inclination, with respect to said direction of extension of said side edge of said brake pads, comprised in a range between 15 and 40 mm, including extreme values.

15. The brake disc according to claim 13, wherein said through slits have an inclination, with respect to said direction of extension of said side edge of said brake pads, of no more than 29.

16. The brake disc according to claim 13, wherein the number of said through slits is a multiple of the number of first connection portions.

17. A brake disc for a bicycle comprising: a first component having a braking track configured to cooperate with brake pads and a plurality of first connection portions that extend towards the inside and that comprise respective first connection areas; a second component having (i) a radially inner annular coupling portion for coupling with a hub of a wheel of the bicycle and (ii) a plurality of second connection portions, in a number corresponding to said plurality of said first connection portions, the second connection portions extending outwards from the radially inner annular coupling portion towards said first component and comprising respective second connection areas; and connecting members active between the first connection areas and the corresponding second connection areas; wherein said second connection portions comprise at least one respective pair of arms that extend between the respective second connection areas and the radially inner annular coupling portion, said pair of arms defining a through opening between them, wherein each second connection portion comprises a reinforcing arm that extends from the respective second connection area and reaches another second connection portion that is arranged circumferentially adjacent to said another second connection portion, wherein each reinforcing arm of a respective second connection portion is substantially parallel to the first connection portion of said first component with which the second connection portion of the second component is associated.

18. A brake disc for a bicycle comprising: a first component having a braking track configured to cooperate with brake pads and a plurality of first connection portions that extend towards the inside and that comprise respective first connection areas; a second component having (i) a radially inner annular coupling portion for coupling with a hub of a wheel of the bicycle and (ii) a plurality of second connection portions, in a number corresponding to said plurality of said first connection portions, the second connection portions extending outwards from the radially inner annular coupling portion towards said first component and comprising respective second connection areas; and connecting members active between the first connection areas and the corresponding second connection areas; wherein said second connection portions comprise at least one respective pair of arms that extend between the respective second connection areas and the radially inner annular coupling portion, said pair of arms defining a through opening between them, said braking track comprises a plurality of through slits, of elongated shape and inclined with respect to a direction of extension of a side edge of said brake pads, wherein said plurality of through slits have an inclination, with respect to said direction of extension of said side edge of said brake pads, comprised in a range between 5 and 60 mm, including extreme values.

19. The brake disc according to claim 18, wherein said first connection area axially overlaps the corresponding second connection area and is housed in a recess of the second connection area.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The features and advantages of the invention will become clearer from the further description of preferred embodiments thereof, made with reference to the attached drawings, where:

(2) FIG. 1 is a perspective view of a first embodiment of a brake disc for a bicycle according to the present invention;

(3) FIG. 2 is a front view of the brake disc of FIG. 1;

(4) FIG. 3 is a side view of the brake disc of FIG. 1;

(5) FIG. 4 is an enlarged view of a portion of the brake disc of FIG. 2, such a portion being defined by the dashed rectangle of FIG. 2;

(6) FIG. 5 is a section view, in enlarged scale, of the brake disc of FIG. 4, taken according to the plane V-V of FIG. 4;

(7) FIG. 6 is a front view of the brake disc of FIG. 1, totally analogous to FIG. 2, in which a brake pad has been added;

(8) FIG. 7 is a rear view of the brake disc of FIG. 1, in which a caliper of a disc brake has been added;

(9) FIG. 8 is a front view of a second embodiment of the brake disc for a bicycle according to the present invention;

(10) FIG. 9 is a front view of the brake disc of FIG. 1, totally analogous to FIG. 2, but having substantially the same scale as FIG. 8;

(11) FIG. 10 is a perspective view of a third embodiment of a brake disc for a bicycle according to the present invention;

(12) FIG. 11 is a section view, in enlarged scale, of a portion of the brake disc of FIG. 10;

(13) FIG. 12 is a perspective view of the brake disc of FIG. 10, taken from the opposite side with respect to FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(14) With initial reference to FIGS. 1-7 and 9, reference numeral 10 wholly indicates a first embodiment of a brake disc for a bicycle according to the present invention.

(15) The brake disc 10 is configured to be mounted on a hub (not illustrated) of a wheel of the bicycle.

(16) The hub is mounted on the frame of the bicycle. In particular, the frame comprises two opposite support arms of the wheel at the respective free end portions of which there are housing seats of opposite free end portions of the hub.

(17) A caliper 12 (FIG. 7) of a disc brake is fixed onto the frame of the bicycle. In particular, the caliper is fixed in a conventional manner to one of the support arms of the wheel.

(18) Inside the caliper 12 there are at least two opposite brake pads 14 (FIG. 6).

(19) The brake disc 10 rotates inside the space defined between the opposite brake pads 14. By actuating the brake lever (not illustrated), the brake pads 14 are brought towards the brake disc 10, generating friction on the brake disc 10 and, consequently, braking the wheel.

(20) In particular, the hub extends along a longitudinal axis X that coincides with the rotation axis of the bicycle wheel and of the brake disc 10 (FIG. 1).

(21) The hub comprises a disc seat for housing and locking in rotation the brake disc 10, and a shoulder, which provides an abutment position in the axial direction for the brake disc 10 mounted on the disc seat.

(22) The disc seat comprises a grooved radially outer surface, i.e. a radially outer surface that extends longitudinally and is provided with longitudinal grooves.

(23) The brake disc 10 comprises a grooved radially inner surface 42a matching that of the disc seat, i.e. a radially inner surface 42a that extends longitudinally and is provided with longitudinal grooves matching those of the grooved radially outer surface of the disc seat.

(24) More in general, the disc seat is shaped according to a shape coupling profile. This term is meant to indicate that the profile of the disc seat has geometric characteristics such as to allow the transmission of a torsion between the hub (on which the disc seat is formed) and the brake disc 10 mounted on such a disc seat with a matching profile. A shape coupling profile can for example be a polygonal profile, or a circular profile with an alteration (for example, leveled along a cord), or other. In particular, the shape coupling profile of the disc seat illustrated in the non-limiting example of the figures is a grooved profile, with ridges and throats, oriented in a direction parallel to the axis X.

(25) The shoulder is adjacent to an axially inner side of the disc seat.

(26) Adjacent to the opposite axially outer side of the disc seat there is a threaded portion, formed at a free end portion of the hub, for coupling with a lock nut (not illustrated), which holds the brake disc 10 in the disc seat, against the shoulder.

(27) The brake disc 10 comprises a first component 30 and a second component 40.

(28) The first component 30 comprises a braking track 32 and the second component 40 comprises a radially inner annular portion 42 for coupling with the hub.

(29) The braking track 32 is configured to cooperate with the brake pads 14 and has a substantially annular extension, so that the radially outer profile of the first component 30 is substantially circular. In order to make the first component 30 less sharp, the radially outer edge 30a of the first component 30 is rounded, as shown in FIG. 3.

(30) The radially inner annular portion 42 is provided with the grooved radially inner surface 42a described earlier.

(31) The first component 30 is preferably made of a first material that ensures good characteristics of braking and of resistance both to oxidation and to wear, like for example steel, whereas the second component 40 is preferably made of a second lighter material, like for example aluminum or alloys thereof or other light alloys. Aluminum (or alloys thereof) is particularly recommended due to its ability to more easily transfer and dispose of the heat developed during braking.

(32) The first component 30 comprises a plurality of first connection portions 34 that extend from the braking track 32 towards the inside (i.e. towards the axis X of the brake disc 10). The first connection portions 34 comprise respective first connection areas 36 at which the first component 30 is connected to the second component 40. The first connection portions 34 are equally circumferentially spaced and, in the example illustrated in FIGS. 1-7 and 9, there are seven of them. In FIGS. 1-7 and 9, so as not to overcomplicate the graphical representation, the reference numerals are indicated only on some of the first connection portions 34, as well as only on some of other elements described hereinafter.

(33) The first connection areas 36 are made at respective free end portions of the first connection portions 34.

(34) In particular, each first connection portion 34 comprises a radially outer end 34a joined to the braking track 32 and a radially inner end 34b at the respective first connection area 36.

(35) In the example illustrated in FIGS. 1-7 and 9, the first connection portions 34 comprise a respective pair of connector elements 35 that extend between the respective first connection area 36 and the braking track 32. The pair of connector elements 35 defines a through opening of elongated shape 37 between them.

(36) The connector elements 35 have a slightly divergent or substantially parallel arrangement, from the respective first connection area 36 towards the braking track 32.

(37) In the example illustrated in FIGS. 1-7 and 9, each connector element 35 has the same axial thickness.

(38) The first connection portion 34 extends in a direction inclined with respect to a radial direction passing through the center of the radially inner annular portion 42 and through the radially inner end 34b. Such an inclination with respect to the radial direction is comprised in the range between 5 and 70, including extreme values, preferably in the range between 30 and 60, including extreme values, and more preferably in the range between 45 and 55, including extreme values.

(39) The braking track 32 comprises a plurality of through slits 32a, of elongated shape and inclined with respect to a direction of extension of a side edge 14a of the brake pads 14 (FIG. 6).

(40) In other words, given that the side edge 14a of the brake pads 14 extends according to a direction substantially parallel to a radial direction that passes through the center of the brake pad 14 and through the center of the brake disc 10, the through slits 32a are substantially inclined with respect to such a radial direction.

(41) The direction of the through slits 32a is defined as the direction along which an edge of such openings extends. Such an edge is preferably the edge of the through slit 32a which firstly comes into contact with the brake pad 14 during normal use of the bicycle.

(42) In particular, the through slits 32a have an inclination, with respect to the direction of extension of the side edge 14a, comprised in the range between 5 and 60, including extreme values, preferably in the range between 15 and 40 including extreme values, and more preferably said inclination is about 29.

(43) All of the through slits 32a have substantially the same inclination, or in any case an inclination comprised in the aforementioned ranges, including extreme values.

(44) The number of through slits 32a is a multiple of the number of first connection portions 34. In particular, in the example illustrated in FIGS. 1-7 and 9, there are seven first connection portions 34 and there are forty-nine slits 32a.

(45) The second component 40 comprises a plurality of second connection portions 44, in equal number to that of the plurality of first connection portions 34. The second connection portions 44 are equally circumferentially spaced. The second connection portions 44 extend outwards from the radially inner annular portion 42 towards the first component 30 and comprise respective second connection areas 46, at which the second component 40 is connected to the first component 30. In FIGS. 1-7 and 9, so as not the overcomplicate the graphical representation, the reference numerals are indicated only of some of the second connection portions 44, as well as only some of other elements described hereinafter.

(46) The second connection areas 46 are made at respective free end portions of the second connection portions 44.

(47) In particular, each second connection portion 44 comprises a radially outer end 44a at the respective second connection area 46 and a radially inner end 44b joined to the radially inner annular portion 42.

(48) The second connection portions 44 comprise a respective pair of arms 45 that extend between the respective second connection area 46 and the radially inner annular portion 42. The pair of arms 45 defines a through opening 47 between them.

(49) The pair of arms 45 has divergent arrangement from the respective second connection area 46 towards the radially inner annular portion 42. Such divergent arms 45 thus extend in different directions.

(50) As illustrated in the attached figures, a first arm 45 of the pair of arms 45 has inclination, with respect to a radial direction passing through the center of the radially inner annular portion 42 and the second connection area 46, opposite to the inclination of the other divergent arm.

(51) Preferably, the first divergent arm 45 is inclined with respect to the other divergent arm by an angle comprised between 15 and 90, more preferably comprised between 20 and 60, even more preferably comprised between 35 and 45.

(52) In the example illustrated in FIGS. 1-7 and 9, each arm 45 has the same axial thickness.

(53) The divergent arms 45 have a non-rectilinear but arched extension.

(54) The arched extension of the divergent arms 45 defines a concavity thereof so that a line passing through the end of an arm 45 constrained to the second connection area 46 and through the end of the same arm constrained to the radially inner annular portion 42 does not intercept portions of the arm comprised between the two ends.

(55) As more clearly illustrated in FIG. 2, the concavity of both divergent arms 45 faces in the same direction.

(56) Preferably, the concavity of an arm 45 directly faces the through opening 37 and the concavity of the arm 45, of the second connection portion 44, circumferentially preceding (in accordance with the direction of rotation of the brake disc) faces the opposite way with respect to the through opening 37.

(57) The through opening 47 has rounded edges at joining areas of each arm 45 with the respective second connection area 46 and with the radially inner annular portion 42. In other words, each arm 45 is connected with the respective second connection area 46 and with the radially inner annular portion 42 without sharp edges, but with rounded edges.

(58) Such rounded edges have radii of curvature comprised in the range between 1 mm and 6 mm, including extreme values, preferably in the range between 2 mm and 4 mm, including extreme values, and more preferably in the range between 2.5 mm and 3 mm, including extreme values. Such radii of curvature make it possible to have a homogeneous distribution of stresses between the divergent arms 45.

(59) Each second connection portion 44 comprises a reinforcing arm 49 that extends from the second connection area 46 and reaches another second connection portion 44 that is located circumferentially adjacent to the aforementioned second connection portion 44.

(60) In particular, each reinforcing arm 49 extends from the second connection area 46 and reaches an arm 45 of the other second connection portion 44 that is located circumferentially adjacent. In the example illustrated in FIGS. 1-7 and 9, the reinforcing arm 49 reaches the divergent arm 45 at or close to its radially outer end 44a.

(61) Each reinforcing arm 49 of a second connection portion 44 has arrangement substantially parallel to that of the first connection portion 34 of the first component 30.

(62) In the example illustrated in FIGS. 1-7 and 9, the reinforcing arms 49 have lower axial thickness than that of the arms 45.

(63) As shown in FIG. 7, the maximum outer diameter of the second component 40 is within a circumference C that does not interfere with the caliper 12.

(64) In other words, the maximum outer diameter of the second component 40 is smaller than the inner diameter of the braking track 32.

(65) The connection between the second connection portions 44 of the second component 40 and the corresponding first connection portions 34 of the first component 30, and in particular the connection between the second connection areas 46 and the corresponding first connection areas 36, takes place through connecting members 50.

(66) Such a connecting member 50 is preferably a rivet 52. The rivet 52 is perforated and is received in respective through holes 36c, 46c formed in the first and second connection area 36, 46. Moreover, the rivet 52 is mounted with axis substantially parallel to the axis X and is caulked. The caulking 52a of the rivet 52 is carried out on the first connection area 36, whereas the shoulder 52b of the rivet 52 rests on the second connection area 46.

(67) The transfer of the braking force takes place through the rivets 52 that work cutting through the contact surface between the first and second connection area 36, 46. The lateral stresses on the brake disc 10 are discharged onto the contact surface between the first and second connection area 36, 46.

(68) As illustrated in FIGS. 4 and 5, the first connection area 36 axially overlaps the corresponding second connection area 46 and is housed in a recess 46a of the second connection area 46.

(69) As illustrated in FIGS. 4 and 5, the first connection area 36 is not radially in contact with the second connection area 46. In other words, a space is provided in the radial direction between side wall 46b of the recess 46a of the second connection area 46 and side wall 36a of the first connection area 36. The side wall 46b and the side wall 36a are arranged substantially parallel to the axis X.

(70) The connecting members 50 are equally spaced apart by a distance L (FIG. 9) comprised in the range between 10 mm and 80 mm, including extreme values, preferably in the range between 20 mm and 50 mm, including extreme values, and more preferably in the range between 35 mm and 40 mm, including extreme values.

(71) FIG. 8 shows a second preferred embodiment of a brake disc for a bicycle in accordance with the present invention, wholly indicated with 10.

(72) In such a FIG. 8, elements that are analogous or functionally corresponding to those described above with reference to the first embodiment illustrated in FIGS. 1-7 and 9 are indicated with the same reference numeral and for their detailed description reference should be made to what has been outlined above.

(73) The second embodiment of the brake disc 10 illustrated in FIG. 8 differs from the one illustrated in FIGS. 1-7 and 9 substantially in that the brake disc 10 has a smaller outer diameter than that of the brake disc 10 illustrated in FIGS. 1-7 and 9, as can be clearly seen from the visual comparison of FIGS. 8 and 9.

(74) For example, the brake disc 10 of FIG. 8 has an outer diameter equal to 140 mm, whereas the brake disc 10 of FIG. 9 has an outer diameter equal to 160 mm.

(75) The distance L between the connecting members 50 of the brake disc 10 of FIG. 8 is substantially unchanged with respect to that of the brake disc 10 of FIG. 9.

(76) In order to obtain this, the number of connecting members 50 of the brake disc 10 of FIG. 8, i.e. the number of first and second connection portions 34 and 44, is less than that of the brake disc 10 of FIG. 9. In particular, there are six connecting members 50 of the brake disc 10 of FIG. 8, instead of the seven connecting members 50 of the brake disc 10 of FIG. 9.

(77) There are six first and second connection portions 34 and 44 of the brake disc 10 of FIG. 8 and there are forty-two through slits 32a.

(78) FIGS. 10-12 show a third preferred embodiment of a brake disc for a bicycle in accordance with the present invention, wholly indicated with 10.

(79) In such FIGS. 10-12, elements that are analogous or functionally corresponding to those described above with reference to the first embodiment illustrated in FIGS. 1-7 and 9 are indicated with the same reference numeral and for their detailed description reference should be made to what is outlined above.

(80) The third embodiment of the brake disc 10 illustrated in FIGS. 10-12 differs from that illustrated in FIGS. 1-7 and 9 substantially in that the second connection areas 46 of the brake disc 10 are not provided with the recesses 46a foreseen in the second connection areas 46 of the brake disc 10 of FIGS. 1-7 and 9. The first connection areas 36 axially overlap the corresponding second connection areas 46, as illustrated in FIGS. 10-12.

(81) In this case, the second component 40 can be made of punched sheet steel, composite material or plastic material.

(82) In particular, the second component 40 can be made of steel and the forming takes place with successive molding operations.

(83) The second component 40 of the brake disc 10 of FIGS. 1-9 is generally made of forged aluminum (or alloys thereof) and then machined.

(84) Of course, those skilled in the art can bring numerous modifications and variants to the brake disc for a bicycle of the present invention, in order to satisfy specific and contingent requirements, all of which are in any case covered by the scope of protection defined by the following claims.