Bicycle disc brake hub

A bicycle disc brake hub is basically provided with a hub axle and a hub shell rotatably disposed about the hub axle. The hub shell has a pair of flanges with a tubular portion extending between the flanges, and a rotor attachment portion configured to prevent an inside diameter of a disc brake rotor from increasing when the diameter of the hub axle increases. The rotor attachment portion is provided in the vicinity of a first shell end of the hub shell, and has a smaller outside diameter than the outside diameter of the tubular portion. A rotor of a disc brake device is attached to the rotor attachment portion.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2006-040078, filed Feb. 17, 2006, Japanese Patent Application No. 2006-103490, filed Apr. 4, 2006 and Japanese Patent Application No. 2006-195376, filed Jul. 18, 2006. The entire disclosures of Japanese Patent Application Nos. 2006-040078, 2006-103490 and 2006-195376 are hereby incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention generally relates to a bicycle hub. More specifically, the present invention relates to a bicycle disc brake hub for mounting a disc brake rotor thereto.

2. Background Information

Bicycling is becoming an increasingly more popular form of recreation as well as a means of transportation. Moreover, bicycling has become a very popular competitive sport for both amateurs and professionals. Whether the bicycle is used for recreation, transportation or competition, the bicycle industry is constantly improving the various components of the bicycle. One component that has been extensively redesigned is the bicycle brake systems.

Recently, bicycles have been equipped with disc brake systems, which are known examples of bicycle brake devices. A disc brake system usually has a caliper connected to a brake lever mounted on the bicycle frame, and a disc brake rotor. The disc brake rotor is fixedly connected to a bicycle disc brake hub provided in the middle of a wheel of the bicycle. A bicycle disc brake hub generally has a hub axle, a hub shell rotatably mounted on the hub axle and a rotor attachment portion fixed to the hub shell. The hub axle is non-rotatably mounted to the bicycle frame. The hub shell is mounted around an external periphery of the hub axle such that it is capable of rotating around the hub axle. The rotor attachment portion configured to attach the disc brake rotor thereto. The hub shell has a cylinder portion provided between a pair of spoke mounting flanges. The rotor attachment portion is provided at one end of the hub shell, and has a greater outside diameter than the cylinder of the hub shell (see, for example, Japanese Laid-Open Patent Application No. 2004-142739 and Japanese Laid-Open Patent Application No. 2004-224337).

Increasing the diameter of the hub axle is an effective measure for improving the rigidity in this type of bicycle disc brake hub. However, if the hub axle is increased in diameter, the outside diameter of the hub shell must also increase accordingly. In this case, with this type of disc brake hub, the outside diameter of the rotor attachment portion increases together with the increase in the diameter of the hub shell. Thus, there must also be an increase in the inside diameter of the rotor attached to the rotor attachment portion.

In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved bicycle disc brake hub. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.

SUMMARY OF THE INVENTION

One object of the present invention is to provide a bicycle disc brake hub minimizes increasing an inside diameter of a rotor of a disc brake when the hub axle is increased.

The foregoing objects can basically be attained by providing a bicycle disc brake hub that basically comprises a hub axle, a hub shell and a rotor attachment portion in accordance with a first aspect of the present invention. The hub axle includes a first axle end and a second axle end with and a center axis extending between the first and second axle ends. The hub shell includes a tubular portion rotatably disposed on the hub axle, a first shell end with a first flange disposed at a first tubular end of the tubular portion, and a second shell end with a second flange disposed at a second tubular end of the tubular portion. The rotor attachment portion is disposed at the first shell end, the rotor attachment portion having a maximum outside diameter that is less than a maximum outside diameter of the tubular portion. In this bicycle disc brake hub, the outside diameter of the rotor attachment portion is less than the outside diameter of the tubular portion of the hub shell. Therefore, it is possible to prevent an increase in the outside diameter of the rotor attachment portion when the hub shell increases in diameter together with the hub axle. It is thereby possible with this bicycle disc brake hub to prevent an increase in the inside diameter of the disc brake rotor when the hub axle is increased in diameter.

According to a second aspect of the present invention, the bicycle disc brake hub of the first aspect of the present invention is provided such that the first shell end is rotatably supported on the first axle end by a first bearing. Also the second shell end is rotatably supported on the second axle end by a second bearing. The hub shell has an internal passage with the hub axle, the first bearing and the second bearing disposed therein, with the internal passage being configured and dimensioned such that the first and second bearings are installed into the internal passage of the hub shell from the second shell end of the hub shell, the first bearing and the second bearing disposed therein. Also the internal passage is configured and dimensioned such that the first and second bearings are installed into the internal passage of the hub shell from the second shell end of the hub shell. In a conventional bicycle disc brake hub, a bearing supporting one end of the hub shell is attached from one end side of the hub shell, and a bearing supporting the other end of the hub shell is attached from the other end side of the hub shell. Therefore, if the outside diameter of the rotor attachment portion provided to one end of the hub shell is reduced, then it may become difficult to attach the bearing that supports that end of the hub shell.

However, in this bicycle disc brake hub, it is possible to insert the first and second bearings into the internal passage from the second shell end side of the hub shell; i.e., the side opposite the one on which the rotor attachment portion is provided. Therefore, the rotor attachment portion is not a hindrance to attaching the first bearing, and the first and second bearings can be easily attached.

According to a third aspect of the present invention, the bicycle disc brake hub of the first or second aspect of the present invention is provided such that the hub shell further includes a spacer disposed in the internal passage between the first and second bearings to maintain separation between the first and second bearings. In this bicycle disc brake hub, the distance between the first and second bearings inserted through the internal passage of the hub shell is maintained by a spacer. There first and second bearings can thereby be disposed at a desired position within the internal passage of the hub shell, and it is no longer necessary, as it is in conventional practice, to form a contact surface for positioning the bearings in the inner peripheral surface of the hub shell.

According to a fourth aspect of the present invention, the bicycle disc brake hub of the third aspect of the present invention is provided such that the internal passage of the hub shell includes an inner peripheral surface with first bearing engagement surface engaging the first bearing and a second bearing engagement surface engaging the second bearing, with the second bearing engagement surface having a greater inside diameter than the first bearing engagement surface. In this bicycle disc brake hub, the inside diameter of the second bearing engagement surface is greater than the inside diameter of the first bearing engagement surface. Therefore, when the first bearing is inserted from the second shell end side of the hub shell through the second bearing engagement surface up to the first bearing engagement surface, it is possible to prevent damage to the second bearing engagement surface that occur from the first bearing coming in contact with the second bearing engagement surface.

According to a fifth aspect of the present invention, the bicycle disc brake hub of the fourth aspect of the present invention is provided such that the second bearing has a greater outside diameter than the first bearing. In this bicycle disc brake hub, since the second bearing has a greater outside diameter than the first bearing, it is possible to prevent spaces from forming between the second bearing and the inner peripheral surface of the hub shell without adding any new separate components even if the inside diameter of the second bearing engagement surface is increased to be greater than the inside diameter of the first bearing engagement surface.

According to a sixth aspect of the present invention, the bicycle disc brake hub of the fourth aspect of the present invention is provided such that the hub shell further includes an intermediate member disposed between an outer peripheral surface of the second bearing and the second bearing engagement surface of the hub shell, and the first and second bearings have outside diameters that are equal. In this bicycle disc brake hub, the area between the outer peripheral surface of the second bearing and the second bearing engagement surface of the hub shell is covered up by the intermediate member. Therefore, it is possible to prevent spaces from forming between the second bearing and the inner peripheral surface of the hub shell even if the inside diameter of the second bearing engagement surface is increased to be greater than the inside diameter of the first bearing engagement surface.

According to a seventh aspect of the present invention, the bicycle disc brake hub of the sixth aspect of the present invention is provided such that the intermediate member is formed integrally with the spacer. In this bicycle disc brake hub, the number of attachment steps can be reduced because the spacer and the intermediate member can be attached to the hub shell simultaneously.

According to an eighth aspect of the present invention, the bicycle disc brake hub of any one of the first to seventh aspects of the present invention is provided such that the rotor attachment portion includes that has a plurality of protuberances circumferential spaced apart to define splines with a bottom diameter that is less than the maximum outside diameter of the tubular portion. In this bicycle disc brake hub, the rotor attachment portion can be made more compact because the rotor can be non-rotatably connected by being fitted with the spline.

According to a ninth aspect of the present invention, the bicycle disc brake hub of any one of the first to seventh aspects of the present invention is provided such that the rotor attachment portion comprises a rotor attachment flange portion with a plurality of circumferential spaced apart bolt threading portions, and a rotor centering portion located on a side of the rotor attachment flange that is opposite to the first flange, the rotor centering portion having a smaller outside diameter than the maximum outside diameter the tubular portion. In this bicycle disc brake hub, the rotor can be fixed in place by using a multipurpose tool because the rotor can be attached by bolt members. Therefore, the rotor can easily be attached and removed.

In the bicycle disc brake hub according to the present invention, the outside diameter of the rotor attachment portion is less than the outside diameter of the tubular portion of the hub shell. Therefore, the outside diameter of the rotor attachment portion can be prevented from increasing when the hub shell increases in diameter together with the hub axle. It is thereby possible, in this bicycle disc brake hub, to prevent increases in the inside diameter of the disc brake rotor when the hub axle is increased in diameter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

Referring initially toFIG. 1, a bicycle101is illustrated is equipped with a front hub1in accordance with a first embodiment of the present invention. The bicycle101basically comprises a frame102, a handlebar104, a drive section105, a front wheel106, a rear wheel107and front and rear disc brake devices108(the rear disc brake device is not shown). The frame102is provided with front and rear suspensions, i.e., a front double-crown suspension fork98in the front and a swing arm100in the rear. The handlebar104is fastened to the suspension fork98. The drive section105basically comprises a chain, a pair of pedals, a pair of derailleurs, and other conventional components. The front and rear wheels106and107are mounted to the suspension fork98and the swing arm100, respectively, as seen inFIG. 1. The front and rear wheels106and107are each provided with a plurality of spokes99.

The front hub1includes a hub axle10mounted on a pair of axle attachment portions98aand98bprovided at the bottom end of the suspension fork98, a hub shell11disposed on the outer peripheral side of the hub axle10, a rotor attachment portion30, a first bearing12and second bearing13disposed between the hub axle10and the hub shell11, and a spacer14, as shown inFIG. 2.

The hub axle10is a substantially cylindrical member having a center hole10a. The hub axle10is non-rotatably mounted between the pair of left and right axle attachment portions98aand98bof the suspension fork98by fastening an attachment bolt15(one example of an attachment axle) disposed to pass through the center hole10a.

The attachment bolt15is an accessory of the suspension fork98. The attachment bolt15has a cylindrical main bolt body16, and a head member17threadedly fixed to the main bolt body16, for example. The outer peripheral surface of the main bolt body16has male threads16aat its distal end, while the inner peripheral surface of the main bolt body16has female threads16bat its proximal end. The male threads16aare threaded into female threads98cthat are formed in the axle attachment portion98b. The head member17is threaded into the female threads16b. Thus, the head member17is threadedly fixed to the main bolt body16at the proximal end. The head member17is provided with a head part17athat is larger than the main bolt body16. The head member17is threadedly fixed in place in the female threads16b. The head part17ais interlocked with the axle attachment portion98ain a state in which the male threads16ais screwed into the axle attachment portion98b, whereby the hub axle10is non-rotatably held in place between the axle attachment portions98aand98b.

The hub axle10has a first axle end21, a second axle end22, and a center axis extending between the first axle end21and the second axle end22as shown by the single-dashed line inFIG. 2. The outer peripheral surface of the hub axle10is provided with a first inner race attachment portion18(seeFIG. 3) positioned on the first axle end21of the hub axle10, and a second inner race attachment portion19(seeFIG. 4) positioned on the second axle end22.

The first inner race attachment portion18is a portion to which a first inner race51of the first bearing12is attached, as will be described later. A first inner race positioning portion20is also provided adjacent to the first axle end21of the first inner race attachment portion18. The first inner race positioning portion20protrudes radially outward from the outer peripheral surface of the hub axle10. The first inner race positioning portion20has a contact surface20athat comes in contact with the first inner race51on the side of first axle end21and restricts the movement of the first inner race51towards the first axle end21.

The second inner race attachment portion19is a portion of the second bearing13to which a second inner race56and a second locking member23are attached, as will be described later. The second inner race attachment portion19has male threads19afor releasably attaching the second inner race56thereto.

The outer peripheral surface of the hub axle10is largest in outside diameter at the first inner race positioning portion20. In other words, the first inner race positioning portion20has the maximum outside diameter of the hub axle10. The outside diameter of the portion between the first inner race positioning portion20and the second axle end22is either the same as the outside diameter of the first inner race attachment portion18or is less than the outside diameter of the first inner race attachment portion18. Therefore, the first inner race51and the second inner race56can be attached to the hub axle10on the second axle end22.

The hub shell11is mounted on the outer periphery of the hub axle10and is capable of rotating about the hub axle10. The hub shell11has a first shell end24, a second shell end25, a pair of flanges40aand40b, a tubular portion40c. The flanges40aand40bare disposed at a distance apart in the axial direction and that interlock with the spokes99. The tubular portion40cis provided between the pair of flanges40aand40b. The first shell end24is provided on the outer side of the flange40aand constitutes one end of the hub shell11. The second shell end25is provided on the outer side of the flange40band that constitutes the other end of the hub shell11, as shown inFIG. 2. The hub shell11is also provided with an internal passage26through which the hub axle10, the first bearing12, the second bearing13, the spacer14, and other components are inserted.

The inner peripheral surface of the hub shell11is provided with a first outer race attachment portion27(seeFIG. 3) and a second outer race attachment portion28(seeFIG. 4). The first outer race attachment portion27is positioned on the first shell end24of the hub shell11. The second outer race attachment portion28is positioned on the second shell end25.

The first outer race attachment portion27(first bearing engagement surface) faces a below-described first outer race50of the first bearing12. The first outer race50is press-fitted into the first outer race attachment portion27. An outer race positioning portion29is provided adjacent to the first shell end24of the first outer race attachment portion27. The outer race positioning portion29is formed to be smaller in diameter than the first outer race attachment portion27. The outer race positioning portion29is positioned on the axially inner side of the first shell end24. The outer race positioning portion29has a contact surface29athat comes in contact with the first outer race50on the side of the first shell end24. The contact surface29arestricts the movement of the first outer race50towards the first shell end24.

The second outer race attachment portion28(second bearing engagement surface) faces a below-described second outer race55of the second bearing13. The second outer race55is press-fitted into the second outer race attachment portion28. The second shell end25of the second outer race attachment portion28is provided with female threads25a. The female threads25aare positioned on the inner side of the second shell end25.

The inside diameter D4of the second outer race attachment portion28is greater than the inside diameter D3of the first outer race attachment portion27by a prescribed distance or spacing, e.g., 0.2 mm to 1.0 mm, preferably 0.3 mm to 0.5 mm, and more preferably 0.4 mm in the present embodiment. The second shell end25and the portion of the inner peripheral surface of the hub shell11that lies between the first outer race attachment portion27and the second outer race attachment portion28are formed to have an inside diameter either equal to or greater than the inside diameter D4of the second outer race attachment portion28. Therefore, the internal passage26of the hub shell11is shaped so as to allow the internal components of the hub shell11that include the first bearing12and the second bearing13to be inserted from the second axle end22.

The rotor attachment portion30is a portion to which a rotor108aof a disc brake device108is attached. The rotor attachment portion30is preferably formed integrally with the first shell end24of the hub shell11, as shown inFIG. 2. The rotor attachment portion30can also instead have a structure that is configured separately from the hub shell11and is integrally fixed in place on the first shell end24. The rotor attachment portion30has an outside diameter D2that is less than the outside diameter D1aof the tubular portion40c. In the present embodiment, the outside diameter D2of the rotor attachment portion30is also less than the inside diameter D1bof the tubular portion40cand the inside diameter of the first shell end24. Thus, by configuring the outside diameter D2of the rotor attachment portion30to be less not only than the outside diameter D1aof the tubular portion40c, but also than the inside diameter D1b, the diameter of the hub axle can be increased to improve rigidity while more effectively preventing an increase in the diameter of the rotor attachment portion30. Specifically, the rotor attachment portion30has a splined section30athat has protuberances disposed at intervals in the circumferential direction to define a plurality of axially extending splines. The rotor attachment portion30is configured so that the outside diameter of the bottom part30b(seeFIG. 3) of the splined section30ais equivalent to the outside diameter D2of the rotor attachment portion30, but is less than the inside diameter D1bof the tubular portion40c. It is even more preferable that the outside diameter not only of the bottom part30bof the splined section30a, but also of the peak30cof the splined section30abe configured so as to be smaller than the inside diameter D1bof the tubular portion40c. The inside diameter of the rotor attachment portion30is also greater than the outside diameter of the hub axle10, and preferably is also greater than the outside diameter of the first inner race51(seeFIG. 3), described later.

A step31is formed in the portion where the rotor attachment portion30and the first shell end24connect, and this step31constitutes a contact surface with which the rotor108acomes in contact, as shown inFIG. 3. The inner peripheral surface of the rotor attachment portion30is provided with female threads33. A rotor locking member32(seeFIG. 2) is threaded into the female threads33to fix the rotor108ain place. The rotor108ais attached to the rotor attachment portion30and is held between the step31and the rotor locking member32, whereby the rotor is non-rotatably fixed in place to the rotor attachment portion30.

The rotor locking member32has a first cylindrical portion32ahaving in its outer peripheral surface a male screw that is threaded into the female threads33of the rotor attachment portion30, and a second cylindrical portion32bthat has a greater outside diameter than the first cylindrical portion32aand that comes in contact with the rotor108a, as shown inFIG. 2. Splines that extend in the axial direction are provided in the outer peripheral surface of the second cylindrical portion32b.

The first bearing12is provided between the hub axle10and the hub shell11, so as to support one end of the hub shell11; i.e., the portion on the side of the first shell end24, in a rotatable manner about the hub axle10. The first bearing12has a first outer race50, a first inner race51and first rolling members52. The first outer race50is attached to the first outer race attachment portion27of the hub shell11. The first inner race51is attached to the first inner race attachment portion18of the hub axle10. The first rolling members52are located between the first outer race50and the first inner race51.

The first outer race50has a ball bearing surface50bthat is a curved surface that curves radially inward. The first outer race50is disposed so as to be sandwiched between the contact surface29aand the spacer14, and is restricted from moving in the axial direction by the contact surface29aand the spacer14.

The first inner race51has a ball pressing surface51bthat is a curved surface that curves radially outward. The first inner race51is pressed in and fixed in place by the first inner race attachment portion18.

The first rolling members52are composed, for example, of spheres that are disposed at equal intervals in the circumferential direction via a retainer, and are also disposed between the first outer race50and the first inner race51.

A sealing member34is disposed on the first shell end24of the first rolling members52, between the outer peripheral surface of the first inner race51and the inner peripheral surface of the first shell end24.

The second bearing13is provided between the hub axle10and the hub shell11, so as to support the other end of the hub shell11; i.e., the portion on the side of the second shell end25, in a rotatable manner about the hub axle10, as shown inFIG. 4. The second bearing13has a second outer race55, a second inner race56and second rolling members57. The second outer race55is attached to the second outer race attachment portion28of the hub shell11. The second inner race56attached to the second inner race attachment portion19of the hub axle10. The second rolling members57are disposed between the second outer race55and the second inner race56.

The second outer race55has a ball bearing surface55bthat is a curved surface that curves radially inward. The second outer race55is disposed so as to be sandwiched between the spacer14and a first locking member35, and is restricted from moving in the axial direction by the spacer14and the first locking member35. The first locking member35is threaded into the female screw25aformed in the inner peripheral surface of the second shell end25. The outside diameter of the second outer race55is greater than the outside diameter of the first outer race50; i.e., the outside diameter of the second bearing13is greater than the outside diameter of the first bearing12by, e.g., 0.2 mm to 1.0 mm, preferably 0.3 to 0.5 mm, and 0.4 mm in the present embodiment.

The second inner race56has a ball pressing surface56bthat is a curved surface that curves radially outward. The end surface of the second inner race56on the side of the second shell end25protrudes outward from the second shell end25of the hub shell11, and is in contact with the second locking member23. The second locking member23is threaded over the male threads19aformed in the outer peripheral surface of the hub axle10.

The second rolling members57are composed, for example, of spheres that are disposed at equal intervals in the circumferential direction by means of a retainer, and are disposed between the second outer race55and the second inner race56.

A sealing member36is provided between the second rolling members57and the first locking member35, and between the outer peripheral surface of the second inner race56and the inner peripheral surface of the second locking member23.

The spacer14is provided between the first bearing12and the second bearing13in the axial direction. The spacer14is used to maintain the distance between the first bearing12and the second bearing13. The spacer14is positioned radially inwardly in relation to the tubular portion40cof the hub shell11, and has a cylindrical shape with an outside diameter that is either the same or slightly less than the inside diameter of the tubular portion40c. The presence of this spacer14eliminates the need to form a contact surface for positioning the bearings in the axial direction by using the inner peripheral surface of the hub shell11as a step. A tube37for preventing grease loss is provided between the spacer14and the hub axle10.

The assembly procedure for the front hub1configured as described above will now be described with reference toFIGS. 2 through 4.

First, the sealing member34, the first rolling members52held by a retainer, and the first outer race50are inserted in this order into the internal passage26of the hub shell11from the second shell end25. These parts are pushed in all the way toward the first shell end24so that the first outer race50is press-fitted to the first outer race attachment portion27. Next, the spacer14and the tube37are inserted into the internal passage26of the hub shell11from the second shell end25. The second outer race55is subsequently inserted into the internal passage26of the hub shell11from the second shell end25, and the second outer race55is press-fitted to the second outer race attachment portion28. The second rolling members held by a retainer are inserted into the internal passage26of the hub shell11from the second shell end25. Then the first locking member35is screwed into and fixed to the second shell end25in a state in which the sealing member36is attached to the inner peripheral surface. The internal components attached in the interior of the hub shell11are inserted into the internal passage26from the second shell end25in this manner. Grease is then filled into the first bearing12and the second bearing13.

Next, the hub axle10is attached to the assembled hub shell11in the state described above. The first inner race51is first attached to the first inner race attachment portion18of the hub axle10. The first inner race51is incorporated into the hub axle10from the second axle end22of the hub axle10; i.e., from the second shell end25in the hub shell11, and is pressed in and fixed to the first inner race attachment portion18.

When the hub axle10is attached to the assembled hub shell11, the hub axle10with the first inner race51attached thereto is inserted into the internal passage26of the hub shell11from the first shell end24, resulting in a state in which the second axle end22of the hub axle10protrudes axially outward from the second shell end25. Next, the second inner race56is attached to the second inner race attachment portion19from the second axle end22of the hub axle10, and its axial position is adjusted. The second locking member23is then attached to the second inner race attachment portion19from the second axle end22of the hub axle10, and the second inner race56is locked in place.

When the rotor108ais mounted on the front hub1that has been assembled in this manner, first, the rotor108ais fitted onto the rotor attachment portion30, and then the rotor locking member32is attached to the rotor attachment portion30and is fastened by an attachment tool3(seeFIG. 5). This attachment tool3has a handheld portion3aand a head portion3bprovided at the distal end of the handheld portion3a. An arcuate concave portion3cthat fits over the outer peripheral surface of the rotor locking member32is provided in the head portion3b, as shown inFIG. 6. Protuberances3dare formed in the concave portion3cto mesh with the grooves provided in the outer peripheral surface of the rotor locking member32.

In this front hub1, the outside diameter D2of the rotor attachment portion30is less than the outside diameter D1aof the tubular portion40cof the hub shell11. Therefore, the diameter D2of the rotor attachment portion30can be prevented from increasing when the hub shell11is increased in diameter together with the hub axle10. It is thereby possible with this front hub1to prevent the inside diameter of the disc brake rotor108afrom increasing when the hub axle10is increased in diameter.

It is difficult to attach the internal components of the hub shell11, including the first bearing12, from the side of the rotor attachment portion30, i.e., from the first shell end24side of the hub shell11, if the outside diameter D2of the rotor attachment portion30is less than the outside diameter D1aof the tubular portion40cof the hub shell11, and the inside diameter of the rotor attachment portion30is less than both the inside diameter D1bof the tubular portion40cof the hub shell11and the inside diameter of the first shell end24.

However, in this front hub1, all of the internal components of the hub shell11can be attached from the opposite side of the rotor attachment portion30; i.e., from the second shell end25side of the hub shell11. Also, inserting the spacer14between the first bearing12and the second bearing13makes is possible to maintain the distance between the first bearing12and the second bearing13, and to dispose the first bearing12and the second bearing13at specific positions. Therefore, the internal components of the hub shell11can be easily attached even if the outside diameter D2of the rotor attachment portion30is relatively small.

In this front hub1, the inside diameter D4of the second outer race attachment portion28is greater than the inside diameter D3of the first outer race attachment portion27as previously described. Also, the outside diameters of the first outer race50and the second outer race55are such that the outside diameter of the second outer race55is greater than the outside diameter of the first outer race50in accordance with the difference between the inside diameter D3of the first outer race attachment portion27and the inside diameter D4of the second outer race attachment portion28, as described above. Therefore, when the first outer race50is passed through the second outer race attachment portion28, the outer peripheral surface of the first outer race50does not come in contact with the second outer race attachment portion28. Alternatively, the first outer race can be passed through while in contact with a lower pressure than when the second outer race55is pressed in by the second outer race attachment portion28. Therefore, the second outer race attachment portion28is not damaged by the outer race50of the first bearing12when the first bearing12is inserted into the internal passage26of the hub shell11before the outer race of the second bearing13is inserted.

Second Embodiment

In the front hub2, the inside diameter D6of a second outer race attachment portion41(second bearing engagement surface) and the inside diameter of a second end42are greater than the inside diameter of the portion on the side having a first shell end43, and the inside diameter D6of the second outer race attachment portion41is greater than the inside diameter D5of a first outer race attachment portion64(first bearing engagement surface). A step44is formed in the second end42side of the second outer race attachment portion41by the difference in inside diameters.

Furthermore, the outside diameter of a second outer race46of a second bearing45is equal to the outside diameter of a first outer race48of a first bearing47, and the outside diameter of the second outer race46is also less than the inside diameter of the second outer race attachment portion41. An intermediate member49is therefore provided between the outer peripheral surface of the second outer race46and the second outer race attachment portion41. The inside diameter D7of the intermediate member49is approximately the same as the outside diameter of the second outer race46, and the second outer race46is press-fitted into the inner side of the intermediate member49. The intermediate member49is formed integrally with a spacer60and has a stepped shape that coincides with the step44in the inner peripheral surface of a hub shell65.

An interlocking groove62is provided in the portion of a second inner race61that protrudes outward from the second end42of the hub shell65, and a cover member63that covers the end surface of the second end42is attached in this interlocking groove62.

The rest of the configuration and the assembly procedure are the same as the front hub1according to the first embodiment.

The same effects as those of the front hub1in the first embodiment can be achieved with the front hub2. Also, since the difference between the inside diameter D5of the first outer race attachment portion64and the inside diameter D6of the second outer race attachment portion41is offset by the intermediate member49, bearings having the same outside diameter can be used as the first bearing47and the second bearing45. Furthermore, since the intermediate member49and the spacer60are formed integrally, they are easily attached to the hub shell65.

In the second embodiment described above, the spacer60and the intermediate member49are formed integrally, but the spacer may also be a separate member. However, it is preferable that they be formed integrally to facilitate attachment to the hub shell65.

Third Embodiment

Referring now toFIGS. 8 and 9, a front hub4in accordance with a third embodiment will now be explained. In view of the similarity between the prior embodiments and third embodiment, the parts of the third embodiment that are identical to the parts of the prior embodiments will be given the same reference numerals as the parts of the prior embodiments. Moreover, the descriptions of the parts of the third embodiment that are identical to the parts of the prior embodiments may be omitted for the sake of brevity.

In the first and second embodiments, a rotor208ais disposed in the rotor attachment portion30, concentrically with the hub axle. The rotor208ais fixed in place by the rotor locking member32that is threaded into the inner peripheral surface of the rotor attachment portion30, but the fixing method is not limited to the methods in these embodiments.

The front hub4of the third embodiment has the same configuration as that of the first embodiment, except for a rotor attachment portion70is provided with the outside diameter of the second bearing13being greater than the outside diameter of the first bearing12, as shown inFIG. 8. Specifically, the outside diameter of the second outer race55is greater than the outside diameter of the first outer race50, and the inside diameter D4of the second outer race attachment portion28is greater than the inside diameter D3of the first outer race attachment portion27. Therefore, the internal passage26of a hub shell71is shaped to allow the internal components of the hub shell71, including the first bearing12and the second bearing13, to be easily inserted from the side with the second axle end22.

The rotor208acan be non-rotatably fixed to the rotor attachment portion70by bolt members69(six, for example). Specifically, the rotor attachment portion70of the hub shell71has a first shell end73with a rotor attachment flange portion75and a tube-shaped rotor centering portion76. The tube-shaped rotor centering portion76is formed on the free end the rotor attachment flange portion75so as to extend outwardly from the outer end face of the hub shell71. The rotor attachment flange portion75has a plurality (six) of bolt threading parts75aand a rotor attachment surface75b. The bolt threading parts75aare located closer to the free end of the first shell end73than the flange40ain the axial direction of the hub axle. The bolt threading parts75aalso protrude outwardly in the radial direction from the first shell end73. The rotor attachment surface75bis formed by the outside faces of the bolt threading parts75athat face in the axial direction of the hub axle, as shown inFIGS. 8 and 9. Threaded holes75cinto which the bolt members69are threaded are formed in each of the bolt threading parts75a.

The rotor208ais a plate-shaped disc member that has a centrally located attachment hole208bfitted over the outer peripheral surface of the rotor centering portion76, and that has six attachment holes208cin the outer peripheral side of the attachment hole208b. When the attachment hole208bin the rotor208ais mounted over the rotor centering portion76, the rotor208ais disposed concentrically with the hub shell71. The outside diameter D8of the rotor centering portion76is less than the outside diameter D1aof the tubular portion40c. In the third embodiment, the outside diameter D8of the rotor attachment flange portion75, which is also the outside diameter of the rotor attachment portion70, is also less than the inside diameter of the tubular portion40c.

When the rotor208ais mounted on the front hub4, which has been assembled in the same manner as in the first embodiment, the rotor208ais first mounted on the rotor centering portion76, and the attachment holes208care aligned with the threaded holes75c. In this state, the six bolt members69are tightened in the threaded holes75cusing an Allen key, a wrench, or another suitable multipurpose tool. The rotor208ais thereby fixed in place on the front hub4.

The same effects as those of the front hub1in the first embodiment can also be achieved with the front hub4. Also, the rotor208acan easily be attached and removed because the rotor208acan be fixed in place using a multipurpose tool.

In the third embodiment described above, six bolt members were used, but the number of bolt members is not limited to six and can be any number.

Fourth and Fifth Embodiments

Referring now toFIGS. 10 and 11, a pair of front hubs5and6in accordance with fourth and fifth embodiments will now be explained. In view of the similarity between the prior embodiments and fourth and fifth embodiments, the parts of the fourth and fifth embodiments that are identical to the parts of the prior embodiments will be given the same reference numerals as the parts of the prior embodiments. Moreover, the descriptions of the parts of the fourth and fifth embodiments that are identical to the parts of the prior embodiments may be omitted for the sake of brevity.

As shown inFIGS. 10 and 11, the hubs5and6have unitized commercial ball bearings as first and second bearings112and113for supporting the hub shells81and91of the hubs5and6. In this case, an outside spacer114aand an inside spacer114bare disposed between the outer races150and155and inner races151and156of the first and second bearings112and113. In this embodiment, the outside diameters of the first and second bearings112and113are equal, but the outside diameter of the second bearing113can also be made greater than the first bearing112to allow the first bearing to be mounted more easily.

Sixth Embodiment

Referring now toFIG. 12, a front hub7in accordance with a sixth embodiment will now be explained. In view of the similarity between the prior embodiments and third embodiment, the parts of the sixth embodiment that are identical to the parts of the prior embodiments will be given the same reference numerals as the parts of the prior embodiments. Moreover, the descriptions of the parts of the sixth embodiment that are identical to the parts of the prior embodiments may be omitted for the sake of brevity.

In the first and second embodiments, the spacer14and the tube37are mounted separately. However, it is also acceptable to configure a spacer314as shown inFIG. 12such that it includes both a spacing function and a grease loss prevention function that are supplied by the spacer14and the tube37of the first and second embodiments.

In the embodiment shown inFIG. 12, the main features of the hub axle10, the hub shell11, and the rotor attachment portion30are the same as in the first embodiment and explanations thereof are omitted here for the sake of brevity. The main differences with respect to the first bearing312and the second bearing313lie in the shapes of the first outer race350and the second outer race355. Otherwise, the constituent features of the first and second inner races51and56and the first and second rolling members52and57are substantially the same as in the first embodiment.

The first outer race350has a curved ball bearing surface350bhaving a curved surface arranged on a radially inwardly facing side thereof. The first outer race350is arranged so as to be sandwiched between the contact surface29aand the spacer314such that axial movement thereof is restricted by the contact surface29aand the spacer314. The second outer race355has a curved ball bearing surface355bhaving a curved surface arranged on a radially inwardly facing side thereof. The outer race355is arranged so as to be sandwiched between the spacer314and the first locking member35such that axial movement thereof is restricted by the spacer314and the first locking member35.

The first outer race350has a first spacer attachment portion350cthat extends radially inward from the ball bearing surface350b, while the second outer race355has a second spacer attachment portion355cthat extends radially inward from the ball bearing surface355b. The spacer314is mounted between the first and second spacer attachment portions350cand355cso as to be coaxial with respect to the hub axle10.

The spacer314is a cylindrical member that can be made of resin, metal, or any of various other materials, but it is preferably made of an aluminum alloy or other lightweight metal. The spacer314is arranged to be close to the outer peripheral surface of the hub axle10such that the gap between the spacer314and the outer peripheral surface of the hub axle10is small. Stepped portions314cand314dare formed on both ends of the spacer314that are configured to mate with the first and second spacer attachment portions350cand355c, respectively. Each of the stepped portions314cand314dis configured to be annularly recessed from the outer peripheral surface of the respective end of the spacer314.

The assembly procedure for the front hub7configured as described above will now be described. First, the sealing member34, the first rolling members52held by the retainer, and the first outer race350are inserted in this order into the internal tube portion26of the hub shell11from the second shell end25. These parts are pushed in all the way toward the first shell end24such that the first outer race350is press-fitted to the first outer race attachment portion27. Next, the spacer314is inserted into the internal tube portion26of the hub shell11from the second shell end25side and the stepped portion314cof the spacer314is fitted into the first spacer attachment portion350c. The second outer race355is subsequently inserted into the internal tube portion26of the hub shell11from the second shell end25, and the second outer race355is press-fitted to the second outer race attachment portion28. At the same time, the stepped portion314dof the spacer314is fitted into the second spacer attachment portion355c. As a result, the spacer314is secured (fixed). The second rolling members57held by the retainer are then inserted toward the second outer race355from the second shell end25, and the first locking member35is screwed into and fixed to the second shell end25in a state in which the sealing member36is attached to the inner peripheral surface thereof. In this way, all of the internal components attached in the interior of the hub shell11are inserted into the internal tube portion26from the second shell end25. Grease is filled into the first bearing312and the second bearing313. Otherwise, the procedure is the same as in the first embodiment and explanations of the subsequent steps are omitted here for the sake of brevity.

With this embodiment, the spacer314serves both to position the first and second outer races350and355in the axial direction and to prevent grease from flowing out of the first and second bearings312and313, i.e., prevent grease loss from the first and second bearings312and313. As a result, the structure of the front hub7can be simplified.

Other Embodiment

In the embodiments described above, a front hub was described as an example, but the present invention can also be applied to a rear hub.

In the embodiments described above, the inside diameter D4of the second outer race attachment portion28of the hub shell11is greater than the inside diameter D3of the first outer race attachment portion27, but the inside diameter D4of the second outer race attachment portion28can also be equal to the inside diameter D3of the first outer race attachment portion27. In this case, bearings having the same outside diameter can be used as the first the second bearings. However, it is preferable that the inside diameter D4of the second outer race attachment portion28be greater than the inside diameter D3of the first outer race attachment portion27as described above, in terms of preventing damage to the second outer race attachment portion28and making it easier to insert the first outer race.

GENERAL INTERPRETATION OF TERMS