Patent Application
20080157585
This application claims the benefit under 35 U.S.C.§119 to Italian Patent Application No. MI2006A002385.
The present invention regards a hub usable in a bicycle wheel having a disc brake.
In bicycle wheels with disc brakes, the brake disc is normally mounted so as to make the disc integral in rotation with the wheel. Known solutions to using disc brakes are flawed in that they either have limited mechanical resistance or they require a relatively thick hub that adds undesired weight or compelxity to the hub.
The problem underlying the present solutions result in the art desiring a hub suitable for a disc brake hub that can be easily mounted without requiring technical solutions which weigh down the hub or complicate its manufacture.
The present invention comprises a tubular body extended axially along a rotation axis of the wheel that includes a coupling profile for reception and locking in position a brake disc. The hub is further characterised by having the disc coupling profile and the locking portion physically separated from each other along the axis of the tubular body. Using this configuration means that the disc position and locking portion are independent from each other and can be chosen and sized in an optimal manner without mutual constraints.
Further characteristics and advantages of the invention will be evident from the following description of several embodiments thereof, made with reference to the attached drawings. In such drawings:
As shown in
With reference in particular to
The tubular body 11 is externally provided with two series of protuberances 14 and 15, not illustrated in detail since they are not concerned with the embodiments of the present invention, for the coupling to the spokes 5. Inside the tubular body 11, a spindle 17 is supported by first and second rolling bearings, respectively 18 and 19. The spindle 17 is of a known construction with right and left terminal portions 20 and 21, firmly fixed to close the opposite ends of the spindle 17 and shaped so as to provide connection seats 22 and 23 to the frame 2 of the bicycle 1. The bearing 18 is of a known one ball row type, while the bearing 19 is of a two ball row type with balls of lesser diameter than those of the bearing 18
Two annular closing caps 24 and 25 are provided between the spindle 17 and the tubular body 11, equipped with respective seals 26 and 27 towards the tubular body 11. The first annular cap 24 (on the right in
It is noted that the mounting of the spindle 17 in the tubular body 11 provides that the left annular cap 25 goes in abutment—towards the left, with reference to FIG. 1—against a projecting flange 29 of the left terminal portion 21 (in turn made integral with the spindle 17, such as by gluing) and abutment—from the right—the inner race 19a of the second bearing 19. The outer race 19b of the same left bearing 19 abutments against a shoulder 31 formed in the tubular body 11; the shoulder 31 therefore defines a housing seat of the left bearing 19 in the tubular body 11. The right bearing 18 race 18b is in abutment against a shoulder 32 formed in the tubular body 11 and its inner race 18a is in abutment against the right annular cap 24. It will be understood that the right annular cap 24, which is screwed on the spindle 17, serves to register the bearing coupling between the spindle 17 and the annular body 11. The annular cap 24 is open ring shaped, and is tightened closed in the mounting on the spindle 17 by means of a transverse grub screw (only indicated schematically with 34), to prevent the loosening of the annular cap 24.
The tubular body 11 has a disc seat 40 for receiving and locking a brake disc (see element 280 in
On the side of body 11 opposite the shoulder 47, a thread 50 is formed for the coupling with a nut which holds the brake disc ( element 280 in
The disc seat 40 and the thread 50 are sized and separately positioned on the tubular body 11 so as to be axially separated by a intermediate portion of tubular body 11 or circumferential groove 60 that is part of neither of them. Thus, there exist a position along the longitudinal X axis in which only the disc seat 40 is present and positions in which only the thread 50 is present; there are no positions in which both the disc seat 40 and the thread 50 are present together or overlapping.
The following conditions are present in the preferred embodiments:
With respect to the predetermined coupling profile, it is preferred that the ribs 44 and grooves 45 have a trapezoidal shape which is symmetric with respect to a radial plane R (see
With reference in particular to
Unlike the hub 10, the hub 110 comprises a pinion-carrier group 170, rotatably mounted on the spindle 117 by means of rolling bearings 171 and 172, and coupled to the tubular body 111 by means of a freewheel connection 173, close to the first end 112 thereof. The pinion-carrier group 170 is of know construction and will not be described in detail below.
An annular closure cap 125 is then provided between the spindle 117 and the tubular body 111, equipped with a seal 127 towards the tubular body 111. The annular cap 125 is screwed on the spindle 117.
It is noted that the mounting of the spindle 117 in the tubular body 111 provides that the inner race 118a of the right bearing 118 goes in abutment—towards the right, with reference to FIG. 5—against a shoulder 129 formed on the spindle 117, while the outer race 118b of the same right bearing 118 receives a shoulder 132 in abutment, formed in the tubular body 111; the shoulder 132 therefore defines a housing seat of the right bearing 118 in the tubular body 111. The left bearing instead has its outer race 119b in abutment—towards the right—against a shoulder 131 formed in the tubular body 111 and its inner race 119a in abutment—towards the left—against the annular cap 125; the shoulder 131 therefore defines a housing seat of the left bearing 119 in tubular body 111. In this manner, it is understood that the annular cap 125, which—as said—is screwed on the pin 117, serves as register element of the bearing coupling between the spindle 117 and the annular body 111. The annular cap 125 is open ring shaped and in the mounting is tightened closed on the spindle 117 by means of a transverse grub screw (indicated only schematically with 134), in order to prevent the loosening of the annular cap 125.
A disc seat 140 is provided outside the tubular body 111 for reception and locking in rotation of a brake disc (not shown in
Close to the disc seat 140, in proximity to its right end 141, the tubular body 111 comprises an outer shoulder 147 which provides an axial abutment position for a brake disc mounted on the disc seat 140.
Still close to the disc seat 140, near its left end 143, a thread 150 is provided formed on an outer portion of the tubular body 111, for the coupling with a threaded ring nut (not shown in
The disc seat 140 and the thread 150 are sized and positioned on the tubular body 111 so as to be axially separate, in the sense specified above. More in particular, the following relations are valid in the hub 110:
One or more holes 154 are made in the thread 150 for the access to the locking grub screw 134 of the annular cap 125.
With reference in particular to
The hub 210 also comprises a brake disc 280 and a threaded ring nut 290. The brake disc 280 comprises a peripheral disc portion 281 which is firmly fixed to a central mounting ring 282; a central hole 284 is made in the mounting ring 282, provided with a splined profile matching the splined profile of the disc seat 240. The brake disc 280 is mounted with the mounting ring 282 on the disc seat 240, locked in rotation by the coupling between the splined profiles of the disc seat 240 and the central hole 284. The ring nut 290 pushes the brake disc 280 against the outer shoulder 247, thus ensuring that the brake disc 280 remains in engagement on the disc seat 240.
In
As already stated, the bearing 19 has two ball rows, a first row 91 closer to the first end 12 of the tubular body 11 and a second row 92 closer to the second end 13 of the tubular body 11. The first ball row 91 runs along a first inner runway 93 made on the inner race 19a and on a first outer runway 94 made on the outer race 19b; the second ball row 92 runs along a second inner runway 95 made on the inner race 19a and a second outer runway 96 made on the outer race 19b.
The runways 93-96 have rounded, particularly semicircular section; the first outer runway 94 is wider than the other runways 93, 95 and 96, in particular it has a radius section R2 greater than the radius R1 of the other runways.
In this manner, the first ball row 91 substantially supports only radial loads and not also axial loads, which are left to the second ball row 92. This ensures a greater slidability of the bearing 19. The fact that the radial load is left to the second row 91, closer to the second end 13 of the tubular body 11, ensures a greater stiffness to the set. The choice, then, of having the runway 94 wider on the outer race 19b rather than on the inner race 19a is due to the consideration that a wider runway reduces the contact area of the balls of the runway, thus increasing the specific pressure; this phenomenon—potentially a source of problems—is more easily acceptable on the outer race 19b, which has a greater circumferential extension than the inner race 19a and therefore lower specific pressures.
It is known that, in a hub according to the invention, such as the hubs 10, 110 and 210, the disc seat 40, 140, 240 does not interfere with the thread 50, 150, 250, improving the mechanical stress conditions in the material of the tubular body 11, 111, 211, which can therefore be designed with a relatively very small thickness.
Moreover, due to the axially separate position of the thread 50, 150, 250 with respect to the disc seat 40, 140, 240, the radial size is much reduced, such that—by possibly employing a reduced left bearing 19, 119, 219, for example with double ball row—it is possible to keep the diameter of the brake disc 40, 140, 240 very small, and thus keep that of the tubular body 11, 111, 211 very small, equivalent to that of a tubular body of a hub for a wheel that does not have a disc brake.
Finally, the presence of the second bearing 19, 119, 219 inside the tubular body 11, 111, 211 at the disc seat 40, 140, 240 contributes to considerably stiffening the tubular body itself, precisely where the braking torque is applied, permitting risk-free mounting even of brake discs 280 with large diameters and great breaking power, such as those typical of so-called downhill bicycles, without requiring an excessive diameter of the tubular body 11, 111, 211.
| Number | Date | Country | Kind |
|---|---|---|---|
| MI2006A002385 | Dec 2006 | IT | national |
