| 摘要 |
PROBLEM TO BE SOLVED: To prevent contaminant such as tooth powder, sputum, blood from entering the inside of a head of a milling tool by covering a gap surrounding the milling tool. SOLUTION: At a seal member 4 to be arranged at a gap 5, a contact piece 4c for covering the gap 5 is formed in contact with the milling tool 3 and at least a part in contact with the milling tool of this piece 4c is constituted of an elastic material. Thus, though the member 4 touches the tool 3, wear is slight, and the contaminant is prevented from entering by comparatively simple structure. |
