Bicycle sprocket and bicycle sprocket assembly

Abstract

A bicycle sprocket has a rotational center axis, and basically includes a first tooth and a second tooth. The first tooth has a first axial chain engaging width. A first axial chain engaging width is smaller than a first axial spacing of the outer link. Further, the first axial chain engaging width is larger than a second axial spacing of an inner link coupled to an outer link. The second tooth has a second axial chain engaging width. The second axial chain engaging width is smaller than the second axial spacing. The second tooth is formed by deformation of the material.

What is claimed: 
     
         1 . A bicycle sprocket having a rotational center axis, the bicycle sprocket comprising:
 a first tooth having a first axial chain engaging width that is smaller than a first axial spacing of an outer link and larger than a second axial spacing of an inner link coupled to the outer link, and   a second tooth having a second axial chain engaging width that is smaller than the second axial spacing, the second tooth being formed by deformation of a material constituting the second tooth.   
     
     
         2 . The bicycle sprocket according to  claim 1 , wherein
 the second tooth is formed by press working.   
     
     
         3 . The bicycle sprocket according to  claim 1 , wherein
 the first tooth includes a recess configured to minimize interference with the inner link, and   the recess is formed by press working.   
     
     
         4 . The bicycle sprocket according to  claim 1 , wherein
 the first tooth includes a recess configured to minimize interference with the inner link, and   the recess is formed by a cutting process.   
     
     
         5 . The bicycle sprocket according to  claim 1 , wherein
 the first tooth comprises a main body portion and an additional portion, the additional portion is attached to the main body portion to increase a width of the main body portion, and   the first axial chain engaging width is obtained by attaching the additional portion to the main body portion.   
     
     
         6 . The bicycle sprocket according to  claim 5 , wherein
 the additional portion is made of metal and attached to the main body portion of the first tooth by one of bonding, diffusion bonding, swaging and casting.   
     
     
         7 . The bicycle sprocket according to  claim 5 , wherein
 the additional portion is non-metallic and attached to the main body portion of the first tooth by one of bonding and integral molding.   
     
     
         8 . The bicycle sprocket according to  claim 1 , wherein
 each of the first tooth and the second tooth comprises a drive surface that has a contact point where a chain roller contacts and a drive surface extension portion that extends in a circumferential direction radially outward from the contact point of the drive surface.   
     
     
         9 . The bicycle sprocket according to  claim 8 , wherein
 each of the first tooth and the second tooth further comprises a non-drive surface, and a non-drive surface extension portion that extends in the circumferential direction from the non-drive surface to suppress radially outward movement of the chain roller.   
     
     
         10 . The bicycle sprocket according to  claim 1 , wherein
 each of the first tooth and the second tooth comprises a drive surface that has a contact point where a chain roller contacts and a drive surface extension portion that extends in a circumferential direction radially outward from the contact point of the drive surface, and   each of the first tooth and the second tooth comprises a non-drive surface and a non-drive surface extension portion that extends in the circumferential direction to suppress the radially outward movement of a chain roller.   
     
     
         11 . The bicycle sprocket according to  claim 1 , further comprising
 a shift region configured to shift the chain during gear shifting.   
     
     
         12 . The bicycle sprocket according to  claim 1 , further comprising
 an annular portion made of metal to which the first tooth and the second tooth are provided on an outer perimeter thereof, and   a non-metallic main body portion attached to an inner peripheral part of the annular portion.   
     
     
         13 . The bicycle sprocket according to  claim 2 , wherein
 the press working is forging.   
     
     
         14 . The bicycle sprocket according to  claim 1 , wherein
 the second tooth is formed by press working and a cutting process.   
     
     
         15 . The bicycle sprocket according to  claims 1 , wherein
 the second tooth is formed by a first pressing step, a cutting step after the first pressing step, and a second pressing step after the cutting step.   
     
     
         16 . The bicycle sprocket according to  claim 15 , wherein
 the second tooth comprises a first surface and a second surface, the first and second surfaces are oppositely facing with respect to an axial direction parallel to the rotational center axis,   the first pressing step is a process for pressing the first surface of the second tooth, and   the second pressing step is a process for pressing the second surface of the second tooth.   
     
     
         17 . The bicycle sprocket according to  claim 16 , wherein
 the cutting step is a process for cutting a protruding portion, which protrudes in the axial direction due to the first pressing step, on the second surface of the second tooth.   
     
     
         18 . A bicycle sprocket having a rotational center axis, the bicycle sprocket comprising:
 a first tooth having a first axial chain engaging width of that is smaller than a first axial spacing of an outer link and larger than a second axial spacing of an inner link coupled to the outer link, and   a second tooth having a second axial chain engaging width that is smaller than the second axial spacing, the first tooth having a substantially octagonal shape as seen from a radially outer side.   
     
     
         19 . The bicycle sprocket according to  claim 18 , wherein
 each of the first tooth and the second tooth has a drive surface that is configured to contact a chain roller, each of the drive surfaces of the first tooth and the second tooth has an axial direction contact width with substantially the same length.   
     
     
         20 . A bicycle sprocket having a rotational center axis, the bicycle sprocket comprising:
 a first tooth having a first axial chain engaging width that is smaller than a first axial spacing of an outer link and larger than a second axial spacing of an inner link coupled to the outer link, and   a second tooth having a second axial chain engaging width that is smaller than the second axial spacing, at least one of the first tooth comprising an inclined portion configured to minimize interference with the inner link.   
     
     
         21 . The bicycle sprocket according to  claim 20 , wherein
 the first tooth further comprises a first surface, a second surface and a third surface that extends in a circumferential direction in between the first surface and the second surface with respect to axial direction that is parallel to the rotational center axis, and   the inclined portion comprises a first chamfered surface that extends from the first surface to the third surface on the drive side, a second chamfered surface that extends from the second surface to the third surface on the drive side, a third chamfered surface that extends from the first surface to the third surface on the non-drive side, and a fourth chamfered surface that extends from the second surface to the third surface on the non-drive side.   
     
     
         22 . The bicycle sprocket according to  claim 20 , wherein
 each of the first tooth and the second tooth has a drive surface that is arranged to contact a chain roller, the drive surfaces of the first and second teeth have an axial direction contact width with substantially the same length.   
     
     
         23 . A bicycle sprocket having a rotational center axis, the bicycle sprocket comprising:
 a first tooth having a first axial chain engaging width that is smaller than a first axial spacing of an outer link and larger than a second axial spacing of an inner link coupled to the outer link, and   a second tooth having a second axial chain engaging width that is smaller than the second axial spacing, at least one of the first tooth and the second tooth comprising a plated layer.   
     
     
         24 . The bicycle sprocket according to  claim 23 , wherein
 the first tooth and the second tooth are made of aluminum, and the plated layer is a nickel plated layer.   
     
     
         25 . The bicycle sprocket according to  claim 23 , wherein
 the first tooth and the second tooth are made of iron, and the plated layer is a nickel chrome plated layer.   
     
     
         26 . A bicycle sprocket assembly comprising
 the bicycle sprocket according to  claim 1 .   
     
     
         27 . The bicycle sprocket assembly according to  claim 26 , wherein
 the sprocket is a single front sprocket.   
     
     
         28 . The bicycle sprocket assembly according to  claim 27 , wherein
 the sprocket is movable around the rotational center axis.   
     
     
         29 . The bicycle sprocket assembly according to  claim 26 , further comprising
 at least one additional front sprocket.   
     
     
         30 . The bicycle sprocket assembly according to  claim 29 , wherein
 the sprocket is movable along the rotational center axis.   
     
     
         31 . The bicycle sprocket assembly according to  claim 26 , wherein
 the sprocket is a rear sprocket.