Abstract: A dustproof structure of a grinding tool holder, which comprises a shaft portion and a counterweight portion connected to one end of the shaft portion. The counterweight portion comprises an eccentric block connected to the shaft portion, at least one bearing mounted in the eccentric block, a dustproof ring, and a grinding member assembling head assembled with the bearing. The eccentric block is formed with an assembly port for disposing the bearing and the dustproof ring, the dustproof ring is located on a side of the bearing facing the grinding member assembling head, and formed with a first continuous concave-convex structure on a side away from the bearing, the grinding member assembling head is formed with a second continuous concave-convex structure on a side facing the dustproof ring, the first and second continuous concave-convex structures match with each other and define dust blocking dots.

Abstract: A grinding machine tool for reducing hotness of a casing, includes a casing and a drive assembly. The casing is divided into a head and a body; includes casing parts; includes an air inlet provided on the body and an air outlet provided on a side of the head; and forms a motor cover on the head, and the motor cover does not contact the casing parts to form an airflow passage in the casing. The drive assembly includes a circuit board, a motor placed into the motor cover, and an airflow generating member rotating synchronously with the motor. When the airflow generating member rotates, it generates a first heat dissipation airflow passing through the airflow passage and dissipating heat of the circuit board and the head, and a second heat dissipation airflow dissipating heat on a side of the motor facing the airflow generating member.

Abstract: An air guider disposed in a grinding machine tool. The grinding machine tool comprises a casing and a motor disposed in the casing. The casing comprises a head for disposing the motor and a body formed with at least one air inlet. The air guider comprises a main body, and an ascending diversion portion integrally formed with the main body, the main body is disposed at a junction between the head and the body, the ascending diversion portion comprises a main guide surface to guide a first heat dissipation airflow entering from the air inlet to flow toward a top of the motor, and two auxiliary guide surfaces respectively disposed on two sides of the main guide surface to generate a second heat dissipation airflow.