JP2518639B2 - Stepping motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the invention [Industrial field of application] The present invention relates to a stepping motor, particularly to a stepping suitable for two-phase excitation, and a magnetic desk drive used for a storage device of an electronic computer. It is used in the device.

[Prior Art] FIG. 2 is a sectional view showing a structure of a stepping motor which has been conventionally practiced, and a sectional view taken along the arrow (b) in FIG.
And (c) a development view showing the relative positions of the pole teeth of the stator and rotor.
Is. In FIG. 2, 1 is a stator housing, 2 is a stator iron core, 3 is a stator winding, 4 and 4 are bearings, 5 is a rotor shaft, 6 and 7 are rotor magnetic poles, and 8 is a permanent magnet. . In FIG. 2, the development view of (c) shows only half of the entire circumference for convenience, but the latter half is symmetrical. 2-1 to 2 in FIG.
2-4 is the main magnetic pole of the stator, a and b are the pole teeth of the stator magnetic pole, 3
Reference numerals -1 to 3-4 denote stator windings, and 1,3,3,4 ... 11,12,13 provided at the tips of the rotor magnetic poles 6 are rotor pole teeth.

The width of the rotor pole teeth is approximately 1 / the pitch of the pole teeth.
The width of the pole teeth of the stator is the same as that of the rotor.

In the figure (c), the stator winding 3-1 is excited and the main magnetic pole 2-1.
Of the main pole 2 and the pole teeth of the rotor are aligned with the pole teeth 1 and 2 of the rotor.
-1/2 of the tooth width overlaps with the pole tooth of the rotor and the pole tooth of the rotor, and the tooth and the valley of the pole tooth of the main magnetic pole 2-3 and the pole tooth of the rotor face each other,
The pole teeth of the main magnetic pole 2-4 and the pole teeth of the rotor face each other in the opposite direction of 2-2 with 1/2 of the tooth width overlapping. (C)
In the figure, when the stator winding 3-1 is de-energized and the stator winding 3-2 is energized, the alignment between the rotor pole teeth 1 and 2 and the stator main pole 2-1 pole teeth is released. , The pole teeth 4 and 5 of the rotor and the pole teeth of the main magnetic pole 2-2 are aligned and face each other and stop.

At this time, the pole teeth of the rotor are 1/2 pitch of the tooth width, that is, 1 / 4θ.
It is rotating by r. As described above, in the stepping motor, the winding to be excited next is sequentially arranged in the winding in which the pole teeth of the magnetic pole around which the winding is wound overlap the pole teeth of the rotor by half the tooth width. By energizing, the rotor can be rotated by 1/2 pitch of the tooth width, that is, by 1 / 4θr. Therefore, since the number of times energization is switched and the rotation angle of the rotor are proportional, the structure is suitable as a control electric motor.

In the above-mentioned excitation method, since the winding to be energized has only one phase and the other phases are not excited, the utilization efficiency of the winding is not good, so there is a two-phase excitation method in which adjacent windings are also excited at the same time. FIG. 3 is a development view in the case of two-phase excitation. Due to space limitations, only three magnetic poles of the stator are shown, but the other parts are second.
It is the same as the figure.

In FIG. 3, the winding 3-1 and the winding 3-2 are excited at the same time, the pole teeth of the rotor are attracted to both magnetic poles, and both pole teeth are 1/4 or 1 / th of their respective tooth widths. Stop at the position where 8θr overlaps each other. Next, in order to rotate the rotor in the right direction, the energization of the winding 3-1 is stopped, and when the winding 3-3 is energized, the rotor rotates 1/2 the pitch of the pole teeth, that is, 1 / 4θr rotation. To do.

The two-phase excitation method has a feature that the rotational force can be increased by √ times because the number of windings that conduct current is two.

[Problems to be Solved by the Invention] However, in the two-phase excitation system shown in FIG. 3, the position where the pole teeth of the rotor stop is an intermediate position between the pole teeth of the two stator magnetic poles that are excited. Since the pole teeth of both the stator and the rotor are not aligned, the inclination of the rotational force becomes smaller,
Further, if the attraction forces of the two magnetic poles are not balanced, there is a problem that the stop position of the rotor deviates and the step angle accuracy deteriorates.

(2) Configuration of the Invention [Means for Solving the Problems] In order to solve the above-mentioned problems of the prior art, the present invention sets the pole tooth width of the rotor to the pole tooth width of the stator magnetic pole. 1 / of
When the rotor is driven by two-phase excitation, at least one small groove is formed on the tip surface of the stator pole teeth so as to correspond to the rotor pole teeth. And the pole teeth of each of the two stator poles are aligned facing each other, increasing the inclination of the rotational force and stopping the rotor even if the attraction forces of the two magnetic poles are slightly different. The structure is characterized in that the position is fixed and a stepping motor with high step angle accuracy can be obtained.

[Operation] Since the pole teeth of the rotor and the pole teeth of the stator are formed so as to face each other when driven by two-phase excitation, fringing is caused by the leakage magnetic flux appearing on the side surface of the pole teeth facing each other. Due to the effect, the inclination of the rotational force becomes large, and the stop position is determined by the arrangement accuracy of the pole teeth, and is determined regardless of some imbalance of the exciting current of the winding, so that the step angle accuracy can be increased.

[Embodiment of the Invention] FIG. 1 is a development view for explaining an arrangement of stator poles and rotor pole teeth of a stepping motor according to the present invention.
12-3 is a magnetic pole of the stator, 3-1 to 3-3 are stator windings,
Symbols a and b are pole teeth provided at the tips of the stator magnetic poles, and the pole teeth are divided by recessed portions 13 provided at the substantially central portions of the respective stator poles, and a-1, a-2, b-1, and b are respectively provided. -2. 1, 2, 3, 4, 5, 6 ... Are pole teeth of the rotor magnetic poles, and the tooth widths of the pole teeth are provided so as to be 1/8 of the arrangement pitch θr of the pole teeth. It is formed to have a width substantially equal to that of the divided pole teeth provided at the tip.

In FIG. 1 (a), the stator windings 3-1 and 3-2 are excited, and the divided pole teeth a-2, b-2, of the magnetic pole 12-1 of the stator are shown.
, And the divided pole teeth a-1 and b-1 of the magnetic pole 12-2 face and are aligned with the pole teeth 1, 2, 3, and 4 of the rotor magnetic pole, respectively. Next, in order to rotate the rotor in the right direction, the stator winding 3-1 is de-energized and the winding 3-3 is energized to divide the stator magnetic pole 12-2 as shown in (b). Pole teeth a-2, b-
2 and the divided pole teeth a-1 and b-1 of the stator magnetic pole 12-3 face and are aligned with the pole teeth 3, 4, 5 and 6 of the rotor, respectively. At this time, the rotor rotates by 1/4 of the arrangement pitch θr of the pole teeth of the rotor and stops. Winding 3 to rotate in the same direction
-2 is stopped and the winding 3-4 is energized, the rotor rotates 1/4 θr in the same direction and stops. In this way, the current supply to one winding is stopped, and the winding provided adjacent to the other winding is supplied with current, whereby the coil can be rotated at a pitch of 1 / 4θr.

Since all the facing pole teeth are aligned as described above, even if the current flowing through the winding is a little unbalanced, fringing effect due to the leakage flux appearing from the side surface of the facing pole teeth As a result, the inclination of the rotational force at the opposite position increases and the positioning accuracy of the rotor increases, and a stepping motor with high step angle accuracy can be configured.

EFFECTS OF THE INVENTION Since the stepping motor according to the present invention is configured as described above, the pole teeth of the rotor magnetic pole and the pole teeth of the stator magnetic pole are aligned and opposed at the stop position when driven by two-phase excitation. However, since the inclination of the rotational force at the stop position becomes large, the error at the stop position can be made small, so that a stepping motor with high step angle accuracy can be configured.

[Brief description of drawings]

1 (a) and 1 (b) are development views showing the relationship between the pole teeth of a stator and a rotor in two-phase excitation of a stepping motor according to the present invention, and FIG. 2 is a conventional stepping process. Sectional views showing the structure of the motor, (a) and (b) and a development view (c) showing the relationship between the stator and rotor pole teeth in one-phase excitation, and FIG. 3 showing the stator in two-phase excitation. It is a development view showing a relation of pole teeth of a rotor. Explanation of reference numerals 1 ... Stator housing, 2 ... Stator iron core, 2-1 to 2-1
2-8, 12-1 to 12-3 ... Stator magnetic poles, 3-1 to 3-8
...... Stator winding, 4,4 …… Bearing, 5 …… Rotor shaft, 6,7…
... Rotor magnetic pole, 8 ... Permanent magnet, 13 ... Stator pole tooth groove, a, b ... Stator pole tooth, a-1, a-2, b-1, b-2 ...
… Stator divided pole teeth, 1,2,3,4,5,6 …… Rotor pole teeth

Claims (1)

(57) [Claims] 1. A stator having a plurality of main magnetic poles each having a winding wound around an annular yoke, and a plurality of pole teeth provided at the tips of the main magnetic poles, and a pole of the stator. Stepping having a plurality of rotor magnetic poles having pole teeth opposed to each other through a gap and a permanent magnet sandwiched between the rotor magnetic poles integrally fixed to a rotor shaft and rotatably supported In the motor, the width of the pole teeth of the rotor is formed to be equal to or less than half the width of the pole teeth of the stator, and the pole teeth of the stator are arranged to face each other with a gap. A stepping motor, characterized in that at least one small groove is provided on the tip surface to divide the pole teeth.