Driving device and driving device unit

A driving device unit to be mounted on a flight vehicle, the driving device unit comprising:

• a driving device configured to drive and rotate a rotor of the flight vehicle;
• and
• a fan configured to rotate about a rotation axis to send gas and arranged in line with the driving device along the rotation axis, wherein
• the driving device includes
• a heat generating part configured to generate heat caused by driving and rotating the rotor,
• a housing having an outer peripheral surface extending along the rotation axis and accommodating the heat generating part,
• an upstream fin provided to the outer peripheral surface and configured to release heat from the heat generating part into the gas,
• a downstream fin provided to the outer peripheral surface at a position downstream of the upstream fin with respect to a flow of the gas in an axial direction of the rotation axis and configured to release heat from the heat generating part into the gas,
• a housing cover defining a first flow passage and a second flow passage between the housing cover and the outer peripheral surface, the upstream fin provided in the first flow passage, the downstream fin provided in the second flow passage, the housing cover covering the outer peripheral surface to allow the gas to flow through the first flow passage and the second flow passage,
• a first inflow port included in the first flow passage and configured to cause the gas to flow from an outside of the housing cover into the first flow passage without causing the gas to pass through the second flow passage, and
• a second inflow port included in the second flow passage and configured to cause the gas to flow from the outside of the housing cover into the second flow passage without causing the gas to pass through the first flow passage.