JP2003259595A5 - - Google Patents

Description

[0002]
[Prior Art]
Among various types of motors, for example, a stepping motor 1 'shown in FIG. 9 includes a rotor 2, a stator 3 facing the rotor 2, and a motor case 4 in which the rotor 2 and the stator 3 are disposed inside. It is roughly configured. The motor case 4 is a metal cup-shaped member having a circular bottom surface 42 in which a support shaft 41 is upright and a cylindrical side wall 43 rising from the periphery of the bottom surface 42 at the center. In the motor case 4, a reduction gear train 7 for decelerating the rotation of the rotation shaft 21 of the rotor 2 is disposed above the rotor 2 and the stator 3 inserted therein.

The motor case 4 is a metal cup-shaped member having a circular bottom surface 42 with a support shaft 41 upright at its center and a cylindrical side wall 43 rising from the periphery of the bottom surface 42, which will be described in detail later. Inside the motor case 4, a reduction gear train 7 for decelerating the rotation of the rotation shaft 21 of the rotor 2 is disposed above the rotor 2 and the stator 3 . The reduction gear train 7 and the rotor 2 and the stator 3 are divided up and down by a resin intermediate plate 81 disposed in the motor case 4. The upper end opening 44 of the motor case 4 above the middle plate 81 is closed by a metal upper plate 82. The top plate 82 supports the tip of a support shaft 41 which stands upright from the bottom surface 42 of the motor case 4.

The first stator core set 31 and the second stator core set 32 configured in this way are integrated by the connector 39 to which the ends of the coil windings 331 and 361 of the first coil bobbin 33 and the second coil bobbin 36 are connected. And in this state are inserted and arranged in the motor case 4. Alternatively, after inserting the first stator core set 31 and the second stator core set 32 into the motor case 4, the connector 39 is attached. In this state, the motor case 4 itself is used as a magnetic path. Therefore, the inner diameter of the cylindrical side wall 43 of the motor case 4 is slightly larger than the outer diameter of the first stator core set 31 and the second stator core set 32. In the motor case, an opening 46 in which the connector 39 is fitted is formed.

With respect to the outer peripheral end face 34a, 35a of the first and second inner stator cores 34, 35 shown in FIG. 3A, corresponding to the formation position of such a second projection 62 , from the reference 0 ° line Notches 341 and 351 shown enlarged in FIG. 3B at four positions 45 °, 135 °, 225 ° and 315 ° counterclockwise, that is, at positions where the second protrusion 62 overlaps the motor axial direction. Is formed. The circumferential width dimension of the notches 341 and 351 is larger than the circumferential width dimension of the second protrusion 62, and the depth dimension of the notches 341 and 351 is the height of the second protrusion 62. Deeper than the direction.