JP2010181267A5 - - Google Patents

Claims (18)

A rotating part formed of a non-magnetic material;
A magnet unit held by the rotating unit and having a predetermined magnetic pattern;
A detection unit for detecting a magnetic field by the magnet unit;
An encoder comprising: a magnetic protection unit provided in the vicinity of the rotating unit and formed to include a magnetic material. The encoder according to claim 1, wherein the magnetic protection unit is held by the rotating unit. The encoder according to claim 1, wherein the magnetic protection unit is formed in an annular shape along a rotation direction of the rotation unit. The encoder according to any one of claims 1 to 3, wherein the magnetic protection part is formed in a peripheral part of the rotating part. The magnetic protection unit is provided at a position overlapping the magnet unit in an axial direction of a rotation axis of the rotation unit or in an axial direction parallel to the rotation axis. The encoder according to any one of the above. The encoder according to any one of claims 1 to 5, wherein the magnetic protection part is provided between the magnet part and the rotating part. The rotating portion has a recess in a portion that holds the magnet portion,
The encoder according to claim 6, wherein the magnetic protection unit is disposed in the recess so as to be sandwiched between the magnet unit and the rotating unit. The encoder according to any one of claims 1 to 7, wherein the magnetic protection unit is provided on a side opposite to the magnet unit with respect to the rotating unit. The encoder according to claim 8, wherein the magnetic protection unit is held by the rotating unit so as to leave a gap between the rotating unit and a rotating shaft of the rotating unit. The encoder according to claim 8 or 9, further comprising a groove formed by the rotating portion and the magnetic protection portion. The encoder according to any one of claims 1 to 10, wherein the magnetic protection unit is held by a magnetic force of the magnet unit. The encoder according to any one of claims 1 to 11, wherein the rotating unit, the magnet unit, and the magnetic protection unit are integrally formed. The rotating unit has a predetermined optical pattern,
The encoder according to any one of claims 1 to 12, further comprising a second detection unit that detects the optical pattern. A rotating part for holding a magnet part having a predetermined magnetic pattern;
A detection unit for detecting a magnetic field by the magnet unit;
A magnetic protective part including a magnetic body and provided in a state of forming a groove part with the hub of the rotating part;
An encoder comprising: The groove is a gap formed between a protrusion provided on the hub and the magnetic protection part.
The encoder according to claim 14. The magnetic protection part is disposed with a gap between the magnetic protection part and a protrusion provided on the hub.
The encoder according to claim 14. The rotating part is provided on a rotating shaft of a rotating body,
The magnetic protection part is disposed in the rotary part on the side where the rotary body is provided when viewed in the axial direction of the rotary shaft.
The encoder according to any one of claims 14 to 16, characterized in that: A second magnetic protection unit provided on a surface opposite to the surface of the rotating unit on which the magnetic protection unit is disposed;
The encoder according to any one of claims 14 to 17, characterized in that: