Rim for a bicycle wheel and respective bicycle wheel, as well as method for manufacturing said rim

Abstract

The invention relates to a rim for a bicycle wheel comprising an annular body with sidewalls wherein at least one sidewall includes a brake track configured to cooperate with a bicycle brake pad. The brake track includes a groove that extends along a helically shaped path.

Claims

1. Rim for a bicycle wheel comprising an annular body having sidewalls, at least one sidewall has a brake track that is configured to cooperate with a bicycle brake pad and includes a single continuous helically shaped groove.

2. Rim according to claim 1, wherein said single continuous helically shaped groove defines a plurality of coils that are spaced apart by a substantially constant distance.

3. Rim according to claim 2, wherein said distance (P) is in a range between about 0.3 mm and about 1.5 mm.

4. Rim according to claim 2, wherein said distance (P) is equal to about 0.5 mm.

5. Rim according to claim 1, wherein said brake track has an average surface roughness in a range between about 0.5 m and about 1.5 m.

6. Rim according to claim 1, wherein said single continuous helically shaped groove has a depth greater than or equal to about 0.02 mm.

7. Rim according to claim 1, wherein said single continuous helically shaped groove has a section shaped substantially like an arc of circumference, having bending radius (R) in a range between about 0.15 mm and about 0.27 mm.

8. Rim according to claim 1, wherein said single continuous helically shaped groove extends substantially for an entire radial height (H) of said brake track.

9. Rim according to claim 1, wherein said annular body is made from light alloy at least at said brake track.

10. Rim according to claim 9, wherein said annular body provided with said single continuous helically shaped groove was treated with plasma electrolytic oxidation.

11. Bicycle wheel comprising a rim according to claim 1.

12. Method for manufacturing a rim for a bicycle wheel, comprising the following steps: providing an annular body with sidewalls; and forming on at least one of said sidewalls a single continuous helically shaped groove in a brake track that is configured to cooperate with a bicycle brake pad.

13. Method according to claim 12, wherein said single continuous helically shaped groove is formed through chip-removal mechanical machining.

14. Method according to claim 12, further comprising the further step of applying a surface treatment of plasma electrolytic oxidation to said annular body.

15. Method according to any one of claim 12, wherein said brake track is formed through mechanical milling or turning machining on said annular body and has an average surface roughness in a range between about 0.5 m and about 1.5m.

16. Rim for a bicycle wheel comprising an annular body with sidewalls having brake tracks configured to cooperate with a bicycle brake pad, wherein at least one of said brake tracks includes a single continuous helically shaped groove.

Description

BRIEF DESCRIPTION OF THE DRAWING(S)

(1) Further characteristics and advantages of the present invention will become clearer from the following detailed description of preferred embodiments thereof, made with reference to the attached drawings, given for indicating and not limiting purposes. In such drawings:

(2) FIG. 1 schematically shows a perspective view of a bicycle wheel according to the present invention;

(3) FIG. 2 schematically shows a perspective view of the rim of the bicycle wheel of FIG. 1;

(4) FIG. 3 schematically shows a perspective view, in enlarged scale, of a portion of the rim of FIG. 2;

(5) FIG. 4 schematically shows a radial section view, in enlarged scale, of the rim of FIG. 2;

(6) FIG. 5 schematically shows an enlarged view of a portion of the radial section of FIG. 4, said portion being drawn inside a dashed rectangle indicated with V;

(7) FIG. 6 schematically shows an enlarged view of a portion the radial section of FIG. 5, said portion being drawn inside a circumference indicated with VI.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

(8) The figures show a rim of a bicycle wheel in accordance with the present invention. Such a rim is indicated with 10, whereas the wheel is indicated with 11.

(9) The rim 10 comprises an annular body 10a configured to be coupled, at a radially outer portion 12 thereof, with a tyre 100 and, at a radially inner portion 14 thereof, with a plurality of spokes 17. For this purpose, a plurality of attachment holes for the heads of the spokes 17 are formed on the radially inner portion 14 of the annular body 10a.

(10) The spokes 17 are connected to a hub 19 (FIG. 1) at the opposite ends to the ends for attachment to the rim 10.

(11) The radially outer portion 12 is separated from the radially inner portion 14 by a separating wall 13 (FIG. 4) that comprises, at the opposite axial end portions thereof, surfaces 13a, 13b providing for supporting the beads of the tyre 100.

(12) The radially inner portion 14 comprises opposite sidewalls 14a, 14b and a bottom wall 14c on which the holes for the attachment of the spokes 17 are formed. Such walls 14a, 14b and 14c, together with the separating wall 13, defined a single closed chamber 140 in the radially inner portion 14 of the rim 10 (FIG. 4).

(13) On each of the aforementioned sidewalls 14a, 14b, or on at least one of the aforementioned sidewalls 14a, 14b, a brake track 20 is formed, which is configured to cooperate with a bicycle brake pad (not shown).

(14) Preferably, the rim 10 is made, at least at the brake track 20, from a metallic material, preferably a light alloy, for example aluminium or alloys thereof. The remaining part of the rim 10 can even be made from a composite material comprising structural fibres incorporated in a polymeric matrix.

(15) In accordance with the present invention, the brake track 20 comprises a helically shaped groove 22 (FIGS. 3 and 5). In the specific example illustrated here, this is a single continuous groove, but what is stated herein has analogous application in the case in which the groove 22 is defined by a plurality of portions of groove.

(16) Such a groove 22 defines, in the brake track 20, a plurality of coils 24 (FIG. 3) which are spaced apart by a distance P (FIG. 6). Preferably, such a distance P is constant, i.e. the coils are equally spaced apart from each other along any radial direction.

(17) The distance P is preferably comprised in the range between about 0.3 mm and about 1.5 mm. More preferably, the distance P is equal to about 0.5 mm.

(18) The brake track 20 preferably has an average surface roughness comprised in the range between about 0.5 m and about 1.5 m. More preferably, the average surface roughness is equal to about 1.0 m. Such values of average surface roughness are obtained upon light milling or turning mechanical machining on the annular body 10a.

(19) The groove 22 preferably has a depth D (FIG. 6) comprised in the range between about 0.02 mm and about 0.07 mm. More preferably, the depth D is comprised in the range between about 0.05 mm and about 0.06, the extremes being included.

(20) With particular reference to FIG. 6, the groove 22 preferably has a section shaped substantially liked an arc of circumference. Such a section preferably has a bending radius R comprised in the range between about 0.15 mm and about 0.27 mm. More preferably, the bending radius R is equal to about 0.21 mm. Such a groove 22 is obtained by carrying out a chip-removal mechanical machining through a tool 26 with a substantially circular head, preferably having a bending radius R corresponding to that of the groove 22 to be obtained (in FIG. 6 the tool 26 is shown in two successive machining positions).

(21) Preferably, the groove 22 extends substantially for the entire radial height H (FIG. 4) of the brake track 20.

(22) The annular body 10a provided with the groove 22 is preferably subjected to a plasma electrolytic oxidation surface treatment.

(23) The method for manufacturing the rim 10 of the present invention comprises, once the annular body 10a has been made, making the brake track 20 on a sidewall 14a or 14b of the annular body 10a.

(24) Preferably, the brake track 20 is made through light milling or turning mechanical machining. This is made in order to obtain the average surface roughness discussed above.

(25) Preliminarily, the annular body 10a can be subjected to a shot blasting operation.

(26) Thereafter, the helically shaped groove 22 is formed on the brake track 20, through chip-removal mechanical machining (like for example milling or deep turning).

(27) This mechanical process is carried out through the tool 26 described above. Such a tool 26 therefore has a bending radius R comprised in the range between about 0.15 mm and about 0.27 mm. More preferably, the tool 26 has a bending radius R equal to about 0.21 mm.

(28) Before or after forming the groove 22 on the annular body 10a the coupling holes for the spokes 17 are formed.

(29) The annular body 10a is finally subjected to a plasma electrolytic oxidation surface treatment, after a washing.

(30) Of course, a man skilled in the art can bring numerous modifications and variants to the rim of a bicycle wheel and to the respective bicycle wheelas well as to the method for manufacturing the rimdescribed above, in order to satisfy specific and contingent requirements, all of which being in any case within the scope of protection of the present invention as defined by the following claims.