JPS63283457A - Variable reluctance motor - Google Patents

Abstract

PURPOSE:To reduce a torque ripple without decreasing an output rotational torque by setting suitably the ratios of the width of each tooth of a rotor and that of each tooth of a stator to the pitch thereof. CONSTITUTION:The distance between respective teeth of a rotor 10, that is, the pitch is regarded as P; the width of each tooth of said rotor 10, as W1; and that of each tooth of a stator 20, as W2. Sizes of the tooth width W1 of said rotor 10 and the tooth width W2 of said stator 20 are such that ratios (W1/P) and (W2/P) are almost 0.35 and 0.45 or almost 0.45 and 0.35, respectively. In order that the rotor 10 is smoothly rotated relative to the stator 20, it is sufficient to control the timing of power application to each pair of magnetic poles according to the corresponding positional relation between respective teeth of the rotor 10 and the stator 20.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a variable reluctance motor, and in particular to a variable reluctance motor, in which rotational torque can be varied without reducing the rotational torque by controlling energization according to the rotational position of the rotor. The present invention relates to a variable reluctance motor that can reduce reluctance as much as possible.

[Conventional technology and problems]

Variable reluctance motors have been used as step motors because of their ease of control. However, if the conventional variable reluctance motor is used as it is, the rotational torque will fluctuate (
Torque ripple) was large and smooth rotation could not be obtained. Therefore, in order to use a variable reluctance motor with simple control characteristics to rotate the rotor as smoothly as a servo motor, some ingenuity is required.

Therefore, in order to solve these problems, it is an object of the present invention to provide a variable reluctance motor that can reduce torque ripple as much as possible without reducing rotational torque, and can obtain smooth rotational torque.

[Means and operations for solving the problems] In view of the above objects of the invention, the present invention provides a variable reluctance motor in which the tooth width of each tooth of the rotor is approximately 35 mm per pitch corresponding to each tooth. %, and the tooth width of the various stator teeth of the stator is approximately 45% of the 1 pitch,
Or the tooth width of the rotor is approximately 45% of the 1 pitch.
In addition, the tooth width of the stator is approximately 35% of the one pitch, and the various types of teeth are adjusted according to the relative movement amount of each tooth of the stator with respect to each tooth of the rotor corresponding to each tooth of the stator. Provided is a variable reluctance smorph characterized by applying a constant current to.

The rotor can be continuously rotated in a desired direction by applying a simple constant current to various parts according to the relative movement amount, and the tooth width of each tooth of the rotor and each tooth of the stator is large. When the value is on the order of the above numerical values, it is possible to provide a variable reluctance morph in which torque ripple is reduced as much as possible without reducing rotational torque.

(Example) The present invention will be described in more detail below based on an example shown in the accompanying drawings. Figure 1 is an enlarged exploded view showing the correspondence between the stator and rotor teeth of a variable reluctance motor.
Figure 2 is an enlarged expanded view showing the relative movement of the stator and rotor shown in Figure 1, Figure 3 is a partially schematic cross-sectional view of the variable reluctance motor, and Figure 4 is a cross-sectional view of the various types of Figure 3. A timing diagram showing the energization timing, FIG. 5(a) is an output torque diagram for a variable reluctance smorph with teeth having the ratio according to the present invention, and FIGS. 5(b) and (c) are ratios different from the ratio according to the present invention. FIG. 4 is an output torque diagram of a variable reluctance motor with teeth of the configuration.

First, referring to FIG. 3, the stator 2 made of magnetic material
0 is provided with six poles A, B, C, A, B, ■, and each type has two teeth, for example, for the A pole, teeth al,
a2 is formed. A rotor 10 made of a magnetic material is provided on the inner circumferential side of the stator 20, and fourteen teeth R1, R2, . . . R14 are formed on the outer circumference of the rotor 10. Further, coils (not shown) are wound around the various poles A, B, . That is, when the pole A side becomes the north pole by energizing the coil, the pole τ side becomes the south pole, and they constitute opposite magnetic poles. The same is true for iB, D, and C. That is, FIG. 3 shows a three-phase variable reluctance motor.

Refer to FIG. 1, which shows the correspondence relationship between the stator 20 and rotor 10 shown in FIG. 3 as an enlarged expanded view. Let P be the interval between each tooth of the rotor 10, that is, 1 bift, Wl be the tooth width of each tooth of the rotor, and W be the tooth width of various teeth of the stator 20.
Set it to 2. The size of the rotor tooth width and stator tooth width recommended by the present invention is the ratio (Wl/P) and the ratio (W2/
P) are approximately 0.35 and approximately 0.45, respectively, or approximately 0.45 and 0.35. The effect of this size will be described later with reference to FIG. FIG. 1 shows the center line SC of the tooth a1 of the stator 20 and the center line RC of the tooth R3 of the rotor 10.
This shows a state of defeat. In order to rotate the rotor 10 smoothly with respect to the stator 20, each pair of 4
It is sufficient to control the timing of energization of one pole A, one λ-1B, and one pole C.

An object of the present invention is to provide effective sizes of rotor teeth and stator teeth for obtaining smooth rotational torque when a constant current is applied. Therefore, the timing at which the constant current 10 is applied is also illustrated in FIG. Further, θ indicates an electrical angle, and the movement of the rotor 10 from the state shown in FIG. 1 by 2 l pitches shown in FIG.
It is assumed to be π. In fact, FIG. 2 shows a state in which the rotor 10 has moved by π relative to the stator 20. For example, if the poles A (and A) are energized from the state shown in FIG. 1 to the state shown in FIG. (towards the left in the figure). Therefore, no current is applied to JiA (and -λ-) during this time. When the electrical angle θ is from π to 2π, that is, the state shown in Figure 2 (θ-
When the pole A (and -man-) is energized from π), the teeth R2 and R3 of the rotor are attracted to the teeth a1 and a2 of the stator, respectively, so that the rotor rotates in the positive direction. Furthermore, when the pole C (and) is energized while the 1!1-air angle θ is from π/3 to 4π/3, the rotor teeth R7 and R8 are attracted to the stator teeth C1 and 02, respectively. The tooth R1 is also attracted by the tooth C2, causing the rotor 10 to rotate in the positive direction. Assuming that the electrical angle θ is between -π/3 and 2π/3 for the poles B and D, the rotor teeth R5 and R6 are the stator teeth, respectively. The rotor 10 can be rotated in the positive direction because it is attracted by the teeth bi and 5 teeth.

As described above, by controlling the timing of energization of various parts according to the rotational relative position of the rotor 10 with respect to the stator 20, it is possible to rotate the rotor 10 in a fixed direction.

However, the torque ripple changes depending on the size of each tooth of the rotor and each tooth of the stator, and an appropriate size may exist. Numerical calculations were performed based on electromagnetic analysis to find a size that would reduce torque ripple as much as possible without reducing rotational torque. In this case, calculations were made for the case where the current applied to each type was a constant current (10) as described above. As a result, when the ratio (Wl/P) and the ratio '(W2/P) are 0.35 and 0.45 (or 0.45 and 0.35), respectively, the torque ripple can be suppressed without reducing the rotational torque. It has been found that this can be reduced as much as possible. The calculation results are shown in FIG. 5(a), where the mechanical rotation angle θ of the rotor is plotted on the horizontal axis and the output torque T is plotted on the vertical axis. For comparison with this calculation result, the ratio (W
l/P) and the ratio (W2/P) are 0.35 and 0.35, respectively.
40 (or 0.40 and 0.35) in Figure 5 (
FIG. 5(C) shows the case where the ratio (Wl/P) and the ratio (W2/P) are 0.35 and 0.35, respectively. These three graphs are drawn on the same scale, and it is clear that case (a) of the present invention has the smallest torque ripple.

The above is true regardless of the number of stator teeth, whether the stator has one tooth for each type or three or more teeth. If the number of phases is n and the number of teeth for each pole is m, then the pitch between the poles on the stator side may be (m+1/n)P (P is the tooth spacing on the rotor side).

〔Effect of the invention〕

As is clear from the above description, according to the present invention, it is possible to provide a variable reluctance motor that can reduce torque ripple as much as possible without reducing output rotational torque and can provide smooth rotation.

[Brief explanation of the drawing]

Figure 1 is an enlarged expanded view showing the correspondence between the stator and rotor teeth of the variable reluctance smorph, and Figure 2 is an expanded view of the variable reluctance smorph.
An enlarged expanded view of the case where the stator and rotor shown in the figure move relative to each other, Figure 3 is a partially schematic cross-sectional view of the variable reluctance motor, and Figure 4 is the timing of energization of various types of motors in Figure 3. FIG. 5(a) is a timing diagram showing the output torque of a variable reluctance motor with teeth having a ratio configuration according to the present invention, and FIGS. The output torque diagram of a variable reluctance motor with teeth. 10... Rotor, 20... Stator,
A, A, B, B, C,...pole, al, a2. al, Ding T, bl, b2. Ball】＼T'T
, c 1 , c 2 , c 1 , τT... Stator teeth, P... Rotor tooth spacing, R1, R2,..., R14... Rotor teeth, Wl.
... Rotor tooth width, W2... Stator tooth width.

Claims (1)

[Claims] 1. A variable reluctance motor, in which the tooth width of each tooth of the rotor is approximately 35% of the 1 pitch corresponding to each tooth, and the tooth width of the stator teeth of each pole of the stator is approximately 35% of the 1 pitch corresponding to the tooth. or the tooth width of the rotor is approximately 45% of the one pitch, and the tooth width of the stator is approximately 35% of the one pitch, and the tooth width of the stator is approximately 45% of the one pitch. A variable reluctance motor characterized in that a constant current is applied to each of the poles in accordance with the amount of relative movement of each tooth with respect to each tooth of the rotor corresponding to each tooth of the stator.