Impeller and fan assembly

An impeller comprising:

• a hub (100) having an axial direction (A-A) as a rotation axis and extending from a first end (101) to a second end (102), and including an end surface (110) and a first wall (121), wherein the end surface (110) is positioned at the first end (101) of the hub (100), one end of the first wall (121) extends around an entire periphery of the end (110) and radially outwardly extends at an angle toward the second end (102) in the axial direction (A-A), wherein a length of extension of the first wall (121) in the axial direction (A-A) is greater than 50% of a length of extension of the hub (100) from the first end (101) to the second end (102) in the axial direction (A-A);
• and
• a plurality of blades (200), proximal ends (201) of which extend from a periphery of the hub (100) in a radial direction (R-R);
• wherein, a predetermined range of angle (A1) is formed between the first wall (121) and the axial direction (A-A), and the predetermined range of angle (A1) is between 3 degrees and 45 degrees.