Patent ID: 11959489
Assignee: ROBERT BOSCH GMBH
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F | IPC F

Claim 9:
10. A fan, the fan comprising:
a hub configured to be driven by motor to rotate about a fan rotational axis;
a band that surrounds the rotational axis and is concentric with the hub, the band including a leading end that faces a direction of airflow through the fan, and a trailing end that is opposed to the leading edge; and
blades that protrude radially from the hub, each blade comprising a root that is connected to the hub and a tip that is connected to a hub-facing surface of the band, wherein
a distance between the fan rotational axis and the band is constant for every location along a line that extends about the circumferences of the band, where the line is disposed on the hub-facing surface of the band at the band trailing end,
a radial dimension of the band is non-uniform along the line such that
the radial dimension varies periodically along the circumference of the band, and
the radial dimension has a maximum value at locations between adjacent blades and a minimum value at locations aligned with a blade.