Breather structure

A breather structure having a communication passage communicating a hydraulic pressure chamber of a hydraulic clutch apparatus with an atmosphere and a stem disposed inside of the communication passage, the breather structure comprising:

• a stem receiving section formed in the communication passage in which the stem is disposed on the side of the hydraulic pressure chamber via a clearance that allows air in the hydraulic pressure chamber to discharge while maintaining a hydraulic pressure within the hydraulic pressure;
• a discharge section formed in the communication passage on the side of the atmosphere, the discharge section opening to the atmosphere;
• a restricting section formed in the inner peripheral surface of the communication passage, the restricting section restricting the movement of the stem toward the discharge section;
• and
• a pit section formed in the inner peripheral surface of the communication passage closer to the side of the hydraulic pressure chamber than the restricting section, the pit section configured to release the clearance to the discharge section.