Heat sink and heat dissipation device

A heat dissipation device, comprising:

• a heat sink, comprising:
• a cylindrical body;
• and
• a plurality of fins, connected to and protrude from the cylindrical body, wherein at least a part of the plurality of fins each comprises a first protrusion portion and a second protrusion portion, a distal edge of the first protrusion portion is located farther away from a central axis of the cylindrical body than a distal edge of the second protrusion portion;
• and
• an airflow generator, disposed on the heat sink, wherein the first protrusion portion is located closer to the airflow generator than the second protrusion portion;
• wherein the heat dissipation device further comprises at least one first fastener, the heat sink further comprises at least one first mount structure connected to the first protrusion portion of one of the part of the plurality of fins, and the at least one first mount structure is configured to be mounted to a circuit board via the at least one first fastener;
• wherein the heat dissipation device further comprises at least one second fastener, the heat sink further comprises at least one second mount structure connected to the first protrusion portion of one of the part of the plurality of fins, and the airflow generator is configured to be installed on the at least one second mount structure via the at least one second fastener;
• wherein a length that the at least one second mount structure protrudes from the distal edge of the first protrusion portion is greater than a distance between the distal edge of the first protrusion portion and the distal edge of the second protrusion portion.

A heat dissipation device, comprising:

• a heat sink, comprising:
• a cylindrical body;
• a first fin assembly, comprising a first mount portion and a plurality of first fins, wherein the first mount portion is mounted on the cylindrical body, and the plurality of first fins are connected to and protrude from the first mount portion;
• and
• a second fin assembly, comprising a second mount portion and a plurality of second fins, wherein the second mount portion is mounted on the cylindrical body, the plurality of second fins are connected to and protrude from the second mount portion, the first mount portion and the second mount portion are in a coaxial arrangement, and lengths of the plurality of first fins are larger than lengths of the plurality of second fins;
• and
• an airflow generator, disposed on the heat sink, wherein the plurality of first fins are located closer to the airflow generator than the plurality of second fins;
• wherein the first mount portion, the second mount portion and the cylindrical body are made of three pieces, and the first mount portion and the second mount portion are arranged side by side along a central axis of the cylindrical body.