JPS62193547A - Step motor - Google Patents

Abstract

PURPOSE:To improve output torque per space volume by winding exciting coils around portions of a stator core between pole teeth. CONSTITUTION:2X3 pole teeth 4-1 to 4-3 and 4-1' to 4-3' projecting toward a rotor 1 are formed in a stator core 3. Exciting coils C-1 and C-3 and C-1' to C-3' are respectively wound around recesses of the stator core 3 between pole teeth. The rotor 1 rotates if an exciting current with a polarity being reversed at an interval of 6pi/6 and with 2pi/6 phase difference from an adjacent phase flows between exciting coils C-1 and C-1', C-2 and C-2', and C-3 and C-3', respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a step motor, and more particularly to the structure of excitation poles.

[Prior Art] As is well known, for example, in a three-phase step motor, there are 2×3 pole teeth 4-1 to 4-3, 4-1 protruding from the rotor 1 as shown in FIG. '~4-3' are provided on the stator core 3, and these pole teeth 4-1~4-3.4-1'~4
-3' respectively, excitation coils C1-C5, CI' ~
By winding C3', the excitation poles φ1 to φ3. φ
1' to φ3', and φ1 and φ1 as shown in Figure 8.
', φ2 to φ2', and φ3 to φ3', the excitation poles are sequentially excited to apply rotational force to the rotor 1 and rotate it.

[Problems to be Solved by the Invention] However, in either the 1-phase excitation method in which the excitation pole of each phase is excited only for one phase, or the 1-2 phase excitation method in which two phases are excited in a temporally overlapping manner, Even if there is, the rotational torque of only the 1#l excitation pole has a minor effect on the rotor, and the other phases do not contribute equally to the rotational torque, so there is a limit to the output torque per space volume. There was a problem.

SUMMARY OF THE INVENTION In view of these problems, it is an object of the present invention to provide a step motor that can improve the output torque per space volume.

[Means for Solving the Problems] According to the present invention, an excitation coil is wound around a stator core between pole teeth.

[When the working excitation coil is wound around the stator core between the pole teeth, the thickness of the stator core is large and the number of turns of the excitation coil can be increased, so it is necessary to increase the rotational torque by this amount.] I can do it.

Embodiment] FIG. 1 is a perspective view showing an embodiment of a three-phase step motor to which the present invention has been applied. 1-4-3.4-1
'~4-3' are formed. The excitation coils C1 to C3 and CI' to C3' are wound in the recesses of the stator core 3 between the pole teeth.

FIG. 2 is a perspective view showing an embodiment of a three-phase linear step motor to which the present invention is applied. Similar to the embodiment of FIG. It is wound around the four parts of the stator core 3 between the pole teeth.

Figure 3 is a wiring diagram for exciting each step motor in Figure 1, φ1 and φ1', φ2 and φ2', φ3.
and φ3' are connected in 111 rows. For example, an excitation circuit as shown in FIG. 4 connects each phase's excitation poles φ1 to φ3. φ1' to φ3' are excited. That is, as shown in FIG. 5(a), when a pulse train having a phase difference of 2π/6 is input to the distribution circuit 10, the distribution circuit 10
As shown in FIGS. 5(b) to 5(d), the sequentially input pulse trains form excitation signals E1 to E3 with an ON time of 6π/6 and a phase difference between adjacent phases of 2π/6. , is input to the excitation circuit 11. Furthermore, the excitation signals E1 to E3 are inverted by inverters 12 to 14, respectively, and are inverted as shown in FIG.
) to (g), inverted excitation signals El' to E3'
and is input to the excitation circuit 11.

The excitation circuit 11 receives these excitation signals E1 to E3 and El.
If '~E3' is input, the signals E1 and El' are connected to the series circuit of the first phase excitation poles φ1 and φ1', and the signal E
2 and E2' are connected to the series circuit of excitation poles φ2 and φ2' of the second phase, and signals E3 and E3' are connected to the excitation poles φ3 and φ3 of the third phase.
′ is applied to the series circuit. As a result, the excitation poles φ1 and φ1'.

Between φ2 and φ2', and between φ3 and φ3', there are
As shown in J), the polarity is reversed every 6π/6, and the excitation current flows with a phase difference of 2π/6 with respect to the adjacent river.

As a result, magnetic flux φ as shown by the arrows in FIG. 6(a) to (C) is sequentially formed between the rotor and the rotor each time the first to third phases are excited, and the rotor 1 rotates. It becomes like this.

In this case, the thrust F that rotates the rotor 1 is F 1/28
N I・t...(1) becomes. However, B is the magnetic flux density in the air gap between the rotor 1 and the pole teeth, N is the number of coil turns per excited pole,
(2) is the excitation current, and t is the thickness of the excitation pole.

Therefore, since the thickness t of the excitation pole is generally greater in the stator core 3 between the pole teeth than in the pole teeth, the thrust force F is improved by this amount.

[Effects of the Invention] As explained above, according to the present invention, since the excitation coil is wound around the stator core between the pole teeth, the output torque per space volume can be improved. . In other words, the shape can be made smaller compared to those with the same output torque.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of a three-phase step motor to which the present invention is applied, FIG. 2 is a perspective view showing an embodiment of a three-phase linear step motor to which the present invention is applied, and FIG. A wiring diagram of the excitation coil, Fig. 4 is a circuit diagram showing an example of an excitation circuit, Fig. 5 is a time chart showing input and output waveforms of the excitation circuit of Fig. 4, and Fig. 6 is an excitation of the step motor shown in Fig. 1. FIG. 7 is a cross-sectional view showing the configuration of a conventional step motor, and FIG. 8 is a diagram showing changes in the excitation state of the step motor shown in FIG. 7. 1... Rotor, 3... Iron core, 4-1 to 4-3.4-
1°~4-3°...Polar teeth, C1~C3, CI'~C
3'... Excitation coil, φ1 to φ3. φ1′～φ3′
... Excitation pole, 11... Excitation circuit. ). Figure 1 4'-1' Figure 2 Figure 3 Figure 4 ((1) E3' Figure 5

Claims (1)

[Scope of Claims] A step motor having 2n (n≧3) pole teeth protruding from a rotor and having an excitation coil wound around each pole tooth, comprising: A step motor characterized by being wound around a stator core between teeth and pole teeth.