To provide a brushless servo motor with an encoder to precisely detect a rotation reference position of a rotor.
The encoder 4 includes an A phase sensor 62, a B phase sensor 63 and a Z phase sensor 64. A pulse signal having a prescribed edge width is output from the Z phase sensor 64 at the rotation reference position of the rotor. The motor includes an edge detecting circuit group 15 for detecting a rising edge and a falling edge of A and B phases and with a rotational direction detecting circuit 17 for detecting a rotational direction of the rotor from the pulse signals of the A and B phases and edge signals of the A and B phases. The motor includes a clear signal output means 12 which detects the rotation reference position of the rotor when the pulse signal of a Z phase and a falling edge signal of the B phase are input while the rotor rotates CCW, and detects the rotation reference position of the rotor when the pulse signal of the Z phase and the falling edge signal of the B phase are input while the rotor rotates CW.
| JPH07190807A | 1995-07-28 | |||
| JP2001116589A | 2001-04-27 | |||
| JPH10274548A | 1998-10-13 | |||
| JP2003185473A | 2003-07-03 |
Tadashi Takahashi
Takashi Watanabe
Suzuki Mitsuyoshi
Kazuya Nishi
Yasuhiko Murayama
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