Linear motor, lens barrel including linear motor, and drive device including linear motor

A lens barrel comprising:

• a lens;
• a lens holder that holds the lens and is movable in an optical axis direction of the lens;
• a fixed part that supports the lens holder so as to be movable;
• a linear motor that generates thrust in the optical axis direction to drive the lens holder, the linear motor comprising:
• a coil that is arranged so that a winding core direction of the coil approximately coincides with the optical axis direction;
• a center yoke part that is arranged in an area inside the coil so as to extend in the optical axis direction;
• a main magnet that is arranged at a position approximately facing the center yoke part in an area outside the coil so that a main magnetization direction of the main magnet intersects perpendicularly with the optical axis direction;
• a back yoke part that is arranged so as to adjoin a magnetized surface of the main magnet that is opposite to a magnetized surface facing the center yoke in the main magnetization direction;
• two sub magnets that approximately adjoin the main magnet and that are arranged in postures where main magnetization directions are inclined with respect to the main magnetization direction of the main magnet;
• and
• two side yoke parts that are arranged so as to approximately adjoin the center yoke part and the back yoke part at front and back positions of a magnet group including the main magnet and the two sub magnets in the optical axis direction,
• wherein at least parts of surfaces of the main magnet that approximately adjoin the two sub magnets are inclined relative to the main magnetization direction of the main magnet, and
• wherein at least parts of surfaces of the two sub magnets that approximately adjoin the main magnet are inclined relative to the main magnetization direction of the main magnet,
• wherein the two sub magnets are lower than the main magnet in a height in the main magnetization direction of the main magnet,
• wherein the main magnet and the two sub magnets are mutually adhered and fixed by applying adhesive to spaces formed on a portion of the inclined surface of the main magnet and adjacent portions of the surfaces of the two sub magnets, and
• wherein one of the coil and a magnetic circuit, which includes the main magnet, the two sub magnets, the center yoke part, the back yoke part, and the side yoke parts, is fixed to the fixed part, and another of the coil and the magnetic circuit is fixed to the lens holder.

A drive device comprising:

• a movable body;
• a fixed part that supports the movable body so as to be movable in a predetermined direction;
• a linear motor that generates thrust in the predetermined direction to drive the movable body, the linear motor comprising:
• a coil that is arranged so that a winding core direction of the coil approximately coincides with the predetermined direction;
• a center yoke part that is arranged in an area inside the coil so as to extend in the predetermined direction;
• a main magnet that is arranged at a position approximately facing the center yoke part in an area outside the coil so that a main magnetization direction of the main magnet intersects perpendicularly with the predetermined direction;
• a back yoke part that is arranged so as to adjoin a magnetized surface of the main magnet that is opposite to a magnetized surface facing the center yoke in the main magnetization direction;
• two sub magnets that approximately adjoin the main magnet and that are arranged in postures where main magnetization directions are similarly inclined with respect to the main magnetization direction of the main magnet;
• and
• two side yoke parts that are arranged so as to approximately adjoin the center yoke part and the back yoke part at front and back positions of a magnet group including the main magnet and the two sub magnets in the predetermined direction,
• wherein at least parts of surfaces of the main magnet that approximately adjoin the two sub magnets are inclined relative to the main magnetization direction of the main magnet,
• wherein at least parts of surfaces of the two sub magnets that approximately adjoin the main magnet are inclined relative to the main magnetization direction of the main magnet,
• wherein the two sub magnets are lower than the main magnet in a height in the main magnetization direction of the main magnet, and
• wherein the main magnet and the two sub magnets are mutually adhered and fixed by applying adhesive to spaces formed on a portion of the inclined surface of the main magnet and adjacent portions of the surfaces of the two sub magnets, and
• wherein one of the coil and a magnetic circuit, which includes the main magnet, the two sub magnets, the center yoke part, the back yoke part, and the side yoke parts, is fixed to the movable body, and another of the coil and the magnetic circuit is fixed to the fixed part.