Abstract: A centrifugal fan with low noise includes a housing, a fan wheel and a recess unit. The fan wheel has a hub and a plurality of fan blade extending outward from the hub radially. The housing has a chamber therein to receive the fan wheel and has a recess unit at the surface thereof. The recess unit is composed of a projection part and a recess part for reducing noise transmission greatly.

Abstract: A fan blade unit in a centrifugal fan includes a hub and a plurality of fan blades connected to the periphery of the hub and each of the fan blades at least has an end edge with at least a baffle part being joined to the end edge and extending toward another one of the fan blades next to it.

Abstract: A fan frame with a fan wheel includes a plurality of guide flow members and a fan wheel. The guide flow members are joined to a rib part with a plurality of ribs in a way of each of the guide flow members being connected to at least one of the ribs. Each guide flow member extends along a curve, which is non-concentric to each other and an opening is defined with the guide flow members. The fan wheel is disposed in the opening with a plurality of fan blades and each of the fan blades has a circumferential side spacing apart from the flow guide members an inconsistent distance for migrating a secondary flow phenomenon between the respective fan blade and the flow guide members.

Abstract: A bearing device capable of correcting deviation automatically includes a bearing, a spindle, an axial barrel, a driving part and an elastic member. The bearing is composed of at least a cone shaped shell member, which defines an orifice. The spindle fits with the bearing via the orifice. The axial barrel provides an inner conical wall corresponding to and fitting with the bearing. The driving part is disposed at a side of the bearing. The elastic member is disposed at a side of the driving part with elastic force thereof urging the driving part to move forward. When a clearance is formed between the bearing and the spindle due to accumulated wear-out occurred via a long period of running, the elastic member presses the driving part to move bearing toward a preset space in the axial barrel such that the orifice is reduced to maintain a tight fit between the spindle and the bearing.

Abstract: A centrifugal blade unit of a cooling fan at least comprises a wheel hub and a plurality of fan blades connected around the circumference of the wheel hub, each having a first blade section and a second blade section that are either connected or bifurcated. Thereby, a reversed flow of a gaseous fluid through the fluid inlet of the cooling fan can be prevented.