Bicycle hub assembly
A bicycle hub assembly includes a hub axle, a hub shell, and a sprocket supporting member. The sprocket supporting member includes a tubular portion and a first tooth. The tubular portion includes an outer peripheral surface and an attachment portion provided only radially inward of the outer peripheral surface. The first tooth is configured to be attached to the attachment portion of the tubular portion. The first tooth includes a first surface and a second surface. The first surface is configured to face a mounting portion of a bicycle sprocket in a circumferential direction of the sprocket supporting member. The second surface is opposite to the first surface in the circumferential direction. The second surface is configured to face the mounting portion of the bicycle sprocket in the circumferential direction.
1. A bicycle hub assembly comprising:
a hub axle;
a hub shell rotatable relative to the hub axle about a rotational axis; and
a sprocket supporting member rotatable relative to the hub axle about the rotational axis and configured to support a bicycle sprocket to be integrally rotatable with the sprocket supporting member about the rotational axis, the sprocket supporting member comprising:
a tubular portion including an outer peripheral surface and an attachment portion provided only radially inward of the outer peripheral surface, the tubular portion being made of a first material; and
a first tooth configured to be attached to the attachment portion of the tubular portion and made of a second material different from the first material, the first tooth comprising:
a first surface configured to face a mounting portion of the bicycle sprocket in a circumferential direction of the sprocket supporting member; and
a second surface opposite to the first surface in the circumferential direction, the second surface being configured to face the mounting portion of the bicycle sprocket in the circumferential direction,
wherein the first tooth is positioned relative to the tubular portion in the circumferential direction only by the attachment portion.
2. The bicycle hub assembly according to claim 1 , wherein
the attachment portion includes a recess provided on the outer peripheral surface of the tubular portion, and
the first tooth includes
a tooth body including the first surface and the second surface, the tooth body being configured to be provided on the outer peripheral surface of the tubular portion in a state where the first tooth is attached to the tubular portion with the attachment portion, and
a protrusion protruding from the tooth body and configured to be disposed in the recess.
3. The bicycle hub assembly according to claim 2 , wherein
the recess extends in an axial direction parallel to the rotational axis.
4. The bicycle hub assembly according to claim 2 , wherein
the recess has a maximum circumferential length such that the protrusion is press-fitted in the recess.
5. The bicycle hub assembly according to claim 2 , wherein
the sprocket supporting member includes a second tooth radially outwardly protruding from the outer peripheral surface of the tubular portion and made of the first material, and
the tooth body has a shape substantially equal to a shape of the second tooth in an axial region where the mounting portion of the bicycle sprocket engages with the tooth body and the second tooth.
6. The bicycle hub assembly according to claim 3 , wherein
the first tooth has a longitudinal axis parallel to the axial direction in a state where the first tooth is attached to the tubular portion with the recess and the protrusion, and
the tooth body and the protrusion extend along the longitudinal axis.
7. The bicycle hub assembly according to claim 6 , wherein
the tooth body has a first maximum axial length defined along the longitudinal axis,
the protrusion has a second maximum axial length defined along the longitudinal axis, and
the second maximum axial length is shorter than the first maximum axial length.
8. The bicycle hub assembly according to claim 2 , wherein
the tooth body has a first maximum circumferential length defined in the circumferential direction in a state where the first tooth is attached to the tubular portion with the recess and the protrusion,
the protrusion has a second maximum circumferential length defined in the circumferential direction in a state where the first tooth is attached to the tubular portion with the recess and the protrusion, and
the second maximum circumferential length is shorter than the first maximum circumferential length.
9. The bicycle hub assembly according to claim 2 , wherein
the tooth body has a first maximum circumferential length defined in the circumferential direction in a state where the first tooth is attached to the tubular portion with the recess and the protrusion,
the protrusion has a second maximum circumferential length defined in the circumferential direction in a state where the first tooth is attached to the tubular portion with the recess and the protrusion, and
the second maximum circumferential length is equal to the first maximum circumferential length.
10. The bicycle hub assembly according to claim 2 , wherein
the attachment portion includes a first inner surface and a second inner surface spaced apart from the first inner surface in the circumferential direction, and
the protrusion includes
a first circumferential end surface configured to face the first inner surface in the circumferential direction, and
a second circumferential end surface configured to face the second inner surface in the circumferential direction.
11. The bicycle hub assembly according to claim 10 , wherein
the first circumferential end surface of the protrusion is disposed on a plane defined by the first surface of the tooth body, and
the second circumferential end surface of the protrusion is disposed on a plane defined by the second surface of the tooth body.
12. The bicycle hub assembly according to claim 2 , wherein
the tooth body includes an inner peripheral surface facing the outer peripheral surface of the sprocket support member,
the attachment portion includes a first inner surface,
the protrusion includes a first circumferential end surface configured to face the first inner surface in the circumferential direction, and
the inner peripheral surface of the tooth body and the first circumferential end surface of the protrusion are positioned on a downstream side of the protrusion in a driving rotational direction of the sprocket support member.
13. The bicycle hub assembly according to claim 12 , wherein
the inner peripheral surface of the tooth body is substantially perpendicular to the first circumferential end surface of the protrusion.
14. The bicycle hub assembly according to claim 3 , wherein
the first tooth has a longitudinal axis parallel to the axial direction in a state where the first tooth is attached to the tubular portion with the attachment portion, and
the first tooth at least partially has a substantially T-shaped cross-section taken along a plane perpendicular to the longitudinal axis.
15. The bicycle hub assembly according to claim 3 , wherein
the first tooth has a longitudinal axis parallel to the axial direction in a state where the first tooth is attached to the tubular portion with the attachment portion, and
the first tooth at least partially has a substantially L-shaped cross-section taken along a plane perpendicular to the longitudinal axis.
16. The bicycle hub assembly according to claim 1 , wherein
the attachment portion includes a plurality of recesses provided on the outer peripheral surface of the tubular portion, and
the first tooth includes
a tooth body including the first surface and the second surface, the tooth body being configured to be provided on the outer peripheral surface of the tubular portion in a state where the first tooth is attached to the tubular portion with the attachment portion, and
a plurality of protrusions protruding from the tooth body and configured to be respectively disposed in the plurality of recesses.
17. The bicycle hub assembly according to claim 1 , further comprising:
a securing member with which the first tooth is to be secured to the attachment portion.
18. The bicycle hub assembly according to claim 17 , wherein
the attachment portion includes a threaded hole, and
the securing member includes an externally threaded part configured to be screwed in the threaded hole.
19. The bicycle hub assembly according to claim 1 , wherein
the first material has a hardness lower than a hardness of the second material.
20. The bicycle hub assembly according to claim 1 , wherein
the first material comprises an aluminum alloy, and
the second material comprises an iron alloy.
21. The bicycle hub assembly according to claim 1 , wherein
the sprocket supporting member includes
a second tooth radially outwardly protruding from the outer peripheral surface of the tubular portion and made of the first material, and
a third tooth radially outwardly protruding from the outer peripheral surface of the tubular portion and made of the first material, the third tooth being spaced apart from the second tooth in the circumferential direction, and
the attachment portion is provided between the second tooth and the third tooth in the circumferential direction.
22. The bicycle hub assembly according to claim 21 , wherein
a distance defined between the attachment portion and the second tooth in the circumferential direction is substantially equal to a distance defined between the attachment portion and the third tooth in the circumferential direction.