Support device with a uniformly sealing locking-piece, and data storage unit provided with such a support device

A support device, comprising:

• a shaft having an axis of rotation and a first bearing surface extending transverse to the axis of rotation;
• a housing enclosing a portion of said shaft, said housing including a seat adjacent said shaft, and said housing and said shaft being rotatable relative to each other;
• a locking piece comprising a second bearing surface for cooperating with said first bearing surface, said locking piece including a positioning surface in contact with said seat on said housing for positioning the second bearing surface relative to said first bearing surface, said seat and said positioning surface being spaced from said first and second bearing surfaces in a direction transverse to said axis of rotation;
• a sealing element disposed against said locking piece for preventing leakage of a working fluid along said locking piece, said sealing element being generally axially aligned with said seat and said positioning surface;
• and
• means for axially biasing said sealing element with pretension against said locking piece, said pretension of said sealing element axially biasing said positioning surface against said seat of said housing, along an axial force transmission path transversely spaced from said first and second bearing surfaces, to position said second bearing surface relative to said first bearing surface.