Patent ID: 9394947
Filing Date: 2016-07-19
CPC Classification: F16D,G03G

Claim Text:
1. A drive transmission device comprising: a rotatable member rotatable in a rotation direction about a rotation axis; a driven member configured to be driven to rotate by rotation of the rotatable member; a driving coupling disposed at an end of the rotatable member; and a driven coupling disposed at an end of the driven member, wherein the driving coupling has a plurality of driving protrusions protruding toward the driven coupling, a centroid of each of the plurality of driving protrusions shifts along a corresponding one of planned lines of the centroid shift with rotation of the driving coupling, each of the planned lines of the centroid shift extends along the rotation direction, the driven coupling has a plurality of driven protrusions corresponding to the plurality of driving protrusions and protruding toward the driving coupling, both the plurality of driving protrusions and the plurality of driven protrusions are arranged at equal intervals in the rotation direction, each of the driving protrusions is in mating contact with the corresponding one of the driven protrusions, a surface of each of the driving protrusions that is in contact with the corresponding one of the driven protrusions includes an inner contact region located closer to a center of the driving coupling than the corresponding planned line of the centroid shift and an outer contact region located closer to a periphery of the driving coupling than the corresponding planned line of the centroid shift, the inner contact region extends along a curve transverse to the rotation direction or along a straight line obliquely transverse to the rotation direction toward the corresponding planned line of the centroid shift, the outer contact region extends along a curve transverse to the rotation direction or along a straight line obliquely transverse to the rotation direction toward the corresponding planned line of the centroid shift, each of the driven protrusions includes an inner linear portion located closer to a center of the driven coupling than the planned line of the centroid shift for the centroid of the corresponding one of the driving protrusions and an outer linear portion located closer to a periphery of the driven coupling than the planned line of the centroid shift for the centroid of the corresponding one of the driving protrusions, the inner linear portion linearly extends along a curve transverse to the rotation direction or along a straight line obliquely transverse to the rotation direction toward the corresponding planned line of the centroid shift, the outer linear portion linearly extends along a curve transverse to the rotation direction or along a straight line obliquely transverse to the rotation direction toward the corresponding planned line of the centroid shift, and each of the driving protrusions is disposed between the inner linear portion and the outer linear portion of the corresponding one of the driven protrusions.