Fan, heat dissipation device and engineering machinery

The invention provides a fan, a heat dissipation device and engineering machinery, and the fan comprises a rotating shaft, a push rod is arranged in the rotating shaft, the end part of the push rod penetrates out of the first end of the rotating shaft, and the push rod is configured to be telescopic; the fan blades are arranged on the peripheral surface of the first end of the rotating shaft, and the fan blades can rotate along the axis of the rotating shaft so as to change the pitch; the driving disc is arranged at the first end of the rotating shaft, and the driving disc is connected with the end part of the push rod; and the two ends of the connecting rod are rotationally connected with the fan blades and the driving disc correspondingly. In the structure, the variable pitch of the fan blades is driven by the driving disc at the end of the rotating shaft, the first end of the rotating shaft is only provided with the hole for the push rod to penetrate out, a large-volume cavity does not need to be machined,