Magnetic unit, position detection apparatus, and magnetic member

A position detection apparatus comprising:

• a magnetic unit including
• a magnetic member;
• a retainer that extends in an axial direction and retains the magnetic member;
• and
• a shaft that is disposed adjacent to the magnetic member in the axial direction and that is coupled to the retainer,
• the magnetic member including
• a magnet that extends in the axial direction and has a first cross-section orthogonal to the axial direction, and a first maximum outer diameter in a radial direction orthogonal to the axial direction, the first cross-section having a substantially constant area in the axial direction, and
• a first magnetic yoke that is disposed adjacent to and disposed to face the magnet in the axial direction and has a second maximum outer diameter in the radial direction, the second maximum outer diameter being greater than the first maximum outer diameter, the first magnetic yoke having no part that overlaps with the magnet when viewed in a direction perpendicular to the axial direction;
• and
• a sensor configured to detect a magnetic field that changes in association with a movement of the magnetic unit along the axial direction, wherein
• the magnetic member is entirely included within the retainer,
• the retainer has a second cross-section orthogonal to the axial direction, and
• the second cross-section has a substantially constant area in the axial direction.

A magnetic member comprising:

• a magnet that extends in an axial direction and has a first cross-section orthogonal to the axial direction, and a first maximum outer diameter in a radial direction orthogonal to the axial direction, the first cross-section having a substantially constant area in the axial direction;
• and
• a magnetic yoke that is disposed adjacent to and disposed to face the magnet in the axial direction and has a second maximum outer diameter in the radial direction, the second maximum outer diameter being greater than the first maximum outer diameter, wherein
• the magnet and the magnetic yoke are arranged adjacent to a shaft in the axial direction,
• the first magnetic yoke has no part that overlaps with the magnet when viewed in a direction perpendicular to the axial direction,
• the magnetic member is entirely included within a retainer,
• the retainer has a second cross-section orthogonal to the axial direction, and
• the second cross-section has a substantially constant area in the axial direction.