Rear sprocket for bicycle transmission
AssigneeShimano Inc.
InventorKenji Kamada
Life of this patent
Estimating the term…
Abstract
A bicycle transmission has among other things a rear hub with a freewheel with an outer freewheel body supporting a plurality of sprockets. A chain is shifted between adjacent pairs of the sprockets by a rear derailleur. Each sprocket includes inner attachment portion and a chain engaging portion having annular root portion and a plurality of teeth. The largest (low gear) sprocket has one or more recesses in the lateral surface that faces towards the center of the bicycle so that the largest (low gear) sprocket overlaps the abutments of the outer freewheel body.
Claims14
A rear sprocket for bicycle transmission comprising:
- an inner attachment portion having a first lateral surface facing in a first axial direction, a second lateral surface facing in a second axial direction and an inner peripheral edge extending between the first and second lateral surfaces;
- an annular root portion located radially outward of the inner attachment portion with the annular root portion having a first side surface facing in the first axial direction and a second side surface facing the second axial direction such that the second side surface and the second lateral surface lie in a common plane;
- and
- a plurality of teeth extending radially outward from an outer periphery of the root portion,
- the inner attachment portion having at least one recess formed on the first lateral surface and extending radially outward from the inner peripheral edge.
An outer freewheel body for bicycle transmission comprising:
- a tubular portion having an outer surface with a plurality of sprocket engaging splines extending in an axial direction to define a plurality of sprocket engaging grooves disposed between the splines;
- and
- an abutment surface disposed at one end of at least one of the splines and facing in a first direction to limit axial movement of a sprocket,
- the grooves having bottom surfaces that extend beyond the abutment surface in an opposite axial direction relative to the first direction.
Dependencies are inferred from the claim text.