Power transmission device

A power transmission device comprising:

• an electromagnetic wave-shielding wall (10) partitioning a first space (1) and a second space (2) adjacent to said first space (1) and blocking propagation of an electromagnetic wave between said first space (1) and said second space (2);
• a rotating shaft (20) rotatably provided and penetrating through said electromagnetic wave-shielding wall (10) to transmit rotational drive force between said first space (1) and said second space (2);
• and
• a bearing (80) rotatably supporting said rotating shaft (20),
• said rotating shaft (20) including a first shaft member (30) pivotally supported by said bearing (80), a shaft joint part (50) provided on an end (31) of said first shaft member (30) on said second space (2) side, and a second shaft member (40) provided to be rotatable together with said first shaft member (30) with said shaft joint part (50) interposed between said first and second shaft members,
• said first shaft member (30) and said second shaft member (40) being formed of a conductive material,
• said shaft joint part (50) having an insulating part (51) formed of an insulating material and blocking propagation of an electromagnetic wave between said first shaft member (30) and said second shaft member (40),
• said bearing (80) including an inner race component part (82, 87) and an outer race component part (83, 88, 16) arranged opposite to each other,
• said inner race component part (82, 87) being formed to fit to said first shaft member (30) and to be rotatable, and
• said outer race component part (83, 88, 16) being formed of a conductive material, being fixed to said electromagnetic wave-shielding wall (10), and having an annular close-contact surface (18) in close contact with said electromagnetic wave-shielding wall (10).