Shimano Inc.

Eigo Kuroiwa

Masahiro Yamanaka

Akinobu Sugimoto

Tetsu Nonoshita

Toshio Tetsuka

Yusuke Nishimoto

Shingo Shiraishi

A bicycle crank assembly is provided with a first sprocket, a second sprocket, a crank arm, a sprocket fixing structure and an alignment tube. The first sprocket includes a plurality of first teeth and at least one first mounting portion having a first mounting opening. The second sprocket includes a plurality of second teeth and at least one second mounting portion having a second mounting opening. The crank arm includes at least one sprocket attachment portion having a third mounting opening. The sprocket fixing structure secures the first and second sprockets to the crank arm via the first, second and third mounting openings. The alignment tube extends through at least two of the first, second and third mounting openings.

Bicycle crank assembly

A bicycle sprocket is provided that includes an external peripheral edge part and an internal peripheral edge part. The external peripheral edge part has a plurality of metal sprocket teeth. The internal peripheral edge part is positioned radially inward of the external peripheral edge part. The internal peripheral edge part is integrally formed as a one-piece unit with the external peripheral edge part. The internal peripheral edge part has at least one recess that extends radially outward from an inner edge of the internal peripheral edge part toward the external peripheral edge part.

Bicycle sprocket

A bicycle crank assembly is basically provided with a crank axle, a first outer shell member, a second outer shell member, a first crank axle supporting member and a second crank axle supporting member. The crank axle has an end portion with an external mounting surface and an internal mounting surface. The first and second outer shell members are arranged relative to each other with a space being formed between the first and second outer shell members. The first crank axle supporting member is disposed on the first outer shell member and supports the external mounting surface of the crank axle. The second crank axle supporting member is disposed on the first outer shell member and supports the internal mounting surface of the crank axle.

A bicycle crank arm has a body member and a cover member that at least partially overlies a peripheral surface of the body member. The body member includes a crank axle attachment portion that has a crank axle receiving opening. A slit extends from the peripheral surface of the body member to the crank axle receiving opening. A fastener bore extends transversely through the slit for adjusting the crank axle receiving opening in size. The peripheral surface of the body member has abutments located on opposite sides of the slit. The abutments are arranged relative to the slit such that the abutments move closer together as the crank axle attachment portion is squeezed to decrease the crank axle receiving opening in size. The cover member contacts the abutments and moves with the abutments as the crank axle attachment portion is squeezed to decrease the crank axle receiving opening in size.

Bicycle crank arm

A bicycle crank assembly is provided with a crank arm including a front side surface and a back side surface. The crank arm has a crank axle mounting portion with a crank axle receiving opening defined by an axle coupling structure. The axle coupling structure at least includes a plurality of full length splines and at least one short spline. The full length splines extends completely in an axial direction of the crank axle receiving opening from a first axial end edge to a second axial end edge. The short spline extends in the axial direction with a truncated end positioned adjacent one of the first and second axial end edges such that the at least one short spline does not extend completely from the other of the first and second axial end edges to the one of the first and second axial end edges.

A bicycle crank assembly is provided with a crank arm and an axial gap adjustment device. The crank arm has a crank axle mounting part, an extension part extending from the crank axle mounting part, a pedal attachment part provided on a radial outer end of the extension part and a sprocket attachment part. The axial gap adjustment device includes an adjustment adapter and an adjustment member. The adjustment adapter has a crank arm engagement structure that non-rotatably engages the crank arm, a first crank axle opening, and a first screw part. The adjustment member has a second crank axle opening, and a second screw part threadedly engaged with the first screw part to selectively position the adjustment member relative to the adjustment adapter.

Growing community of inventors

Osaka, Japan

Eigo Kuroiwa