Thin type counter-rotating axial air moving device

A counter-rotating axial air moving device, comprising:

• a front rotor fan, comprising a front hub and a plurality of front blades arranged annularly and spacedly on a periphery of the front hub, wherein the front hub comprises a front hub diameter, and each of the front blades comprises a front average pitch angle;
• the plurality of front blades defining a front blade diameter, and a ratio of the front hub diameter to the front blade diameter is 0.3 to 0.85, and the front average pitch angle is greater than 46 degrees;
• rear rotor fan, disposed on a downstream side of the front rotor fan, and comprising a rear hub and a plurality of rear blades arranged annularly and spacedly on a periphery of the rear hub, wherein the rear hub comprises a rear hub diameter, and each of the rear blades comprises a rear average pitch angle;
• the plurality of rear blades defining a rear blade diameter, and a ratio of the rear hub diameter to the rear blade diameter is 0.3 to 0.85, and the rear average pitch angle is less than 38 degrees;
• and
• a stator component, located between the front rotor fan and the rear rotor fan;
• wherein, an amount of the front blades is greater than or equal to an amount of the rear blades, the front rotor fan and the rear rotor fan are stacked with each other of a total thickness, wherein the total thickness is defined as a thickness of the front hub, a thickness of the stator component and a thickness of the rear hub;
• and a ratio of the total thickness to the greater one between the front blade diameter and the rear blade diameter is less than or equal to 0.75.