Patent ID: 8870528
Filing Date: 2014-10-28
Classification: F04D,F05D

Abstract:
1. A ventilation fan comprising: an impeller arranged to rotate around a center axis; a motor portion arranged to rotate the impeller; a motor supporting portion arranged to support the motor portion; and a housing arranged to accommodate the impeller and the motor portion; wherein the motor supporting portion includes a substantially disk-shaped base portion and a substantially cylindrical bearing holding portion extending axially with the center axis as the center, at least the base portion being made from a resin material; on at least one of an upper surface and a lower surface of the base portion, a plurality of recessed portions which are axially recessed; and a flat portion of the base portion excluding the recessed portions does not have a continuous region extending in a straight line radially along a radial direction from the center of the base portion.