Spindle and cutting apparatus including the same

A spindle comprising:

• a housing including a first opening and a second opening;
• a bearing housed in the housing;
• a main shaft rotatably supported by the bearing, the main shaft being provided with a first through hole passing through the main shaft in an axial direction of the main shaft, the main shaft including:
• a first end located on a first side in the axial direction, located adjacent to the first opening, and extending out of the housing through the first opening;
• and
• a second end located on a second side in the axial direction and located adjacent to the second opening;
• a collet chuck disposed in the first through hole, the collet chuck being movable in the axial direction, the collet chuck including:
• a first collet end located adjacent to the first end of the main shaft, the first collet end being able to grip a machining tool to machine a workpiece;
• and
• a second collet end located on the second side in the axial direction;
• a draw bar disposed in the first through hole, the draw bar being movable in the axial direction, the draw bar including:
• a first bar end located adjacent to the first end of the main shaft and connected to the second collet end;
• and
• a second bar end located adjacent to the second end of the main shaft;
• and
• a cover covering the first opening, the cover being provided with a second through hole through which the main shaft extends;
• wherein
• the main shaft and the cover are disposed at a distance from each other;
• the housing includes:
• an air inlet which is located above the bearing and through which air is introduced into the housing;
• an air passage through which the air introduced into the housing through the air inlet flows into the second through hole;
• and
• an air outlet which is located between the main shaft and a portion of the cover where the second through hole is provided and through which the air inside the housing is discharged out of the housing;
• the spindle further includes a coolant container attached to the housing, the coolant container being provided with a nozzle which is located on the second side in the axial direction with respect to the air outlet and from which a coolant is to be discharged onto the machining tool;
• a distance between an axis of the main shaft and the air outlet in a radial direction of the main shaft is less than a distance between the air outlet and the nozzle;
• and
• a lower end of the nozzle is located inward of an outer edge of the cover in the radial direction of the main shaft.