JP2515965Y2 - Stepping motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a stepping motor, and more particularly to a stepping motor capable of stable driving with high resolution.

[Prior Art] Generally, stepping motors are used in various industrial fields, and those having a small size as shown in FIG. 15 are also frequently used.

The stepping motor 1 shown in FIG.
The components shown in FIG. 16 are housed therein, and the output shaft 4 of the rotor 3 is formed so as to protrude from the front side of the housing 2. The rotor 3 is magnetized to have four poles in the circumferential direction, and
It is rotatably supported in the center of the inside. This rotor 3
Two yoke arm parts 5a, 5b, 6a, 6 on the left and right of
Substantially U-shaped yokes 5 and 6 each having a b
The tips of a, 5b, 6a, 6b are fixed so that the tips thereof face the rotor 3. That is, each yoke arm portion 5a, 5b, 6a, 6
b is made to face the rotor 3 with facing surfaces 5as, 5bs, 6as, 6bs consisting of arcuate concave surfaces. Are formed with an adjacent facing surface
5bs and 6as are formed with a phase of 45 degrees. Excitation coils 7 and 8 are respectively wound around the yokes 5 and 6 around the yoke arm portions 5a and 6b.

In the conventional stepping motor 1 thus formed, the rotor 3 is driven by energizing the coils 7 and 8 of the yokes 5 and 6 according to a predetermined timing chart.
It is driven to rotate in 45 degree steps.

[Problems to be solved by the device]

However, in the conventional stepping motor 1, since the facing surfaces 5as, 5bs, 6as, 6bs of the pair of yokes 5, 6 are not arranged rotationally symmetrically with respect to the rotor 3, the rotor 3 is stable. Opposite surface 5bs, 6bs to drive
The central angle θ ₁ of θ and the central angle θ ₂ of the facing surfaces 5as and 6as are θ ₁ <θ ₂
However, stable driving of the rotor 3 is still insufficient.

Further, in the above-mentioned conventional example, it is desired to realize a stepping motor which has a simple structure and can be rotated with a high resolution because half step driving of 45 degree steps cannot be performed.

The present invention has been made in view of these points, and provides a stepping motor capable of rotating and driving a rotor with high resolution and stably, and having a simple structure, easy assembly, and low cost. The purpose is to

[Means for solving the problem]

To achieve the above object, a stepping motor according to the present invention is provided with a rotor magnetized to have a plurality of poles in a circumferential direction, and has at least two yoke arm portions on each extension line of one diameter of the rotor. A pair of shaped yokes are arranged in the axial direction of the rotor, and phase-differences are provided at positions symmetrical to each other about the extension line of the diameter, and the yoke arms are connected to the rotor. It is characterized in that the center lines of the respective facing surfaces are arranged at equal positions in the circumferential direction of the rotor.

[Action]

According to the present invention, by using four yokes of the same shape having at least two yoke arm portions, the center lines of the surfaces of the respective yoke arm portions facing the rotor are evenly arranged in the circumferential direction of the rotor. Therefore, by exciting each yoke according to a predetermined time chart, it is possible to stably rotate the rotor with high resolution.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

1 to 11 show one embodiment of the present invention. In this embodiment, a rotor magnetized with four poles is driven to rotate by exciting eight yoke arm portions.

That is, the stepping motor 11 of the present embodiment is the second
As shown in the figure, the housing 12 is formed by mounting the constituent parts inside a housing 12 that is long in the left and right. At the center of the housing 12, a rotor 13 magnetized with four poles in the circumferential direction is rotated. The small-diameter portion below the shaft 14 is rotatably provided by being supported by the bearing portion 15 portion of the housing 12. An output pinion 16 is formed on the upper end of the rotary shaft 14 and is exposed from a small hole 17 of the housing 12. On the left and right sides of the rotor 13 in the housing 12, on the extension lines of the diameter D of the rotor 13,
A pair of identically formed yokes A1, A2, B1, B2 made of plate material are arranged in the axial direction of the rotor 13, and the arrangement from the plane is the diameter D of the rotor 13 (the left and right sides of the rotor 13 in FIG. 1). (Diameter in the direction) is provided so as to be line-symmetric with respect to the extension line. Each yoke A1, A2, B1, B2 has two yoke arm parts A1a, A1b, A2a, A2b, B1a, B1b, B2a, B2.
It is formed in a substantially U shape having b, and faces the rotor 13 at the tip of each yoke arm A1c, A1d, A2c, A2d, B1c, B1d,
The central angles of B2c and B2d are the same, and eight facing surfaces A1c
The center line of B2d is arranged at a position that divides the circumferential direction of the rotor 13 into eight equal parts. Explaining with the yoke A1 as a reference,
The yoke A1 is formed in a substantially U-shape by connecting the bases of a yoke arm portion A1a near the extension line of the diameter D of the rotor 13 and a distant yoke arm portion A1b, and the facing surfaces of the tips of the respective yoke arm portions A1a, A1b. The center lines of A1c and A1d are arranged at a phase of 90 degrees. In contrast to this yoke A1, the yoke A2 is provided with the front and back reversed and provided directly below the yoke A1, and the yoke B1 is provided with the front and back reversed and facing the yoke A1 at the same height. The yoke B2 has the same front and back as the yoke A1 and is provided so as to face the yoke A2 at the same height. Then, the yoke arms A1, A2, B1 and B2 of the yoke arms A1a, A2b, B1b,
Excitation coils LA1, LA2, LB1, and LB2 are wound around B2a, respectively. The yokes A1, A2, B1, B2 have spacers 18, 18 at their bases so that the yoke arms A1b ... Is supported in this way.

Excitation by the coils LA1 ... LB2 of the stepping motor 11 of the present embodiment thus formed may be performed by the drive circuit shown in FIGS. 7 and 8.

On the other hand, FIG. 7 shows two coils LA1 and LB2 in phase.
And a pair of two coils LB1 and LA2 are energized. In the figure (a), the emitters whose conduction states are controlled by the energization control voltages Va and Vb are connected. A coil LA is provided between the emitters of the two pairs of transistors T _r1 and T _r2 and the transistors T _r3 and T _r4.
1 and coil LB2 are connected in series, and transistors T _r2 , T
Drive voltage V _c is applied to the collector of _r3
The collectors of T _r1 and T _r4 are grounded. Further, FIG. 2B shows a coil LB1 and LA2 connected in series between the emitters of two pairs of transistors T _r5 and T _r6 and transistors T _r7 and T _r8 as in the case of FIG. is there. In these drive circuits, the energization control voltages Va, Vb are controlled so that the energization directions of the coils LA1, LB2 and LB1, LA2 are set in the rightward direction in FIGS. 7 (a) and (b). The direction can be switched to the opposite direction to the left.

On the other hand, FIG. 8 shows that the coils LA1, LA2, LB1, LB2 are separately connected in series with the transistors T _r1 , T _r2 , T _r3 , T _r4 so that they can be excited individually. is there.

Next, the rotation operation of the stepping motor 11 of this embodiment will be described.

First, a case where the rotor 13 is rotated by 45 degrees in steps will be described.

As one method, it is advisable to excite the coils LA1, LA2, LB1, LB2 in the drive circuit shown in FIGS. 7 (a) and 7 (b) in two sets of two phases, contrary to the timing chart shown in FIG. In this case, the current flows through the coils LA1 and LB2 in the forward direction during the first T ₁ time, and the current flows through the coils LB1 and LA2 in the forward direction during the next T ₂ time, causing the rotor 13 to rotate 45 degrees from T ₁ time. When the rotor is rotated, the current flows in the opposite direction to the coils LA1 and LB2 in the next T ₃ hours, and the rotor 13
It is rotated 45 degrees from ₂ o'clock, and in the next T ₄ time, current flows through the coils LB1 and LA2 in the opposite direction, and the rotor 13 is rotated 45 degrees from T ₃ o'clock. By repeating this one cycle, the rotor 13
Is rotated in 45 degree steps.

The other method is to drive each coil LA1, LA2, LB1, in the drive circuit of FIG. 8 in reverse of the timing chart shown in FIG.
It is good to excite LA2 with two phases and one.

Next, a case where the rotor 13 is rotationally driven in steps of 22.5 degrees will be described.

In this case, the drive circuit shown in FIG. 7 (a) (b), by energizing 1-2 phase according to the timing chart shown in FIG. 11, each time the _{T 1, T 2 ... T 8} 22.5 The rotor 13 is rotated only once. By repeating this one cycle, the rotor 13 is rotationally driven in steps of 22.5 degrees.

12 and 13 show another embodiment of the present invention, 1
The two yokes A1 will be explained.
The yoke arm portion A1b farther than the extension line of the diameter D of the rotor 13 is linearly formed by widening the distance between a and A1b as compared with the above-described embodiment to simplify the shape of the cylinder and the yoke arm portion A1.
The coil LA1 wound on the a side is the coil LA of the lower yoke A2.
2 and the plane position do not overlap.

FIG. 14 shows another embodiment of the present invention, in which the rotor 13 is magnetized to have 12 poles in the circumferential direction, and each yoke A1, A2, B
1, B2 and the like are the same as in the above embodiment.

In this embodiment, the coils LA1, LA2, LB1, and LB2 are excited in two phases by one to rotationally drive the rotor 13 in 15 degree steps, and by exciting in 1-2 phases, the rotor 13 is rotated in 7.5 degree steps. It can be driven.

In each of the above embodiments, each yoke has two yoke arm portions, but the number of yoke arm portions may be three or more.

As described above, according to each of the embodiments, the plurality of facing surfaces A1c,
Since A1d ... B2d can be evenly arranged in the circumferential direction with respect to the rotor 13, the rotor 13 can be rotationally driven extremely stably.

Further, the four yokes A1, A2, B1 and B2 can be formed by the same yoke, and the yokes can be easily manufactured by press punching instead of the conventional drawing process. It is simple and the cost is greatly reduced.

Further, half-step driving, which was difficult in the conventional example, can be performed extremely easily by changing the excitation method of each coil.

It should be noted that the present invention is not limited to the above-mentioned embodiments, but can be modified as necessary.

[Effect of device]

As described above, since the stepping motor of the present invention is constructed and operates, the rotor can be rotationally driven with high resolution and stably, and the structure is simple, the assembly is easy, and the cost is low. There are effects such as becoming.

[Brief description of drawings]

1 to 11 show one embodiment of the stepping motor of the present invention, FIG. 1 is a plan view of the state in which the upper part of the housing is omitted, and FIG. 2 is taken along the line II-II of FIG. FIG. 3 is a sectional view, FIG. 3 and FIG. 4 are lines III-III and IV- in FIG. 2, respectively.
FIG. 5 is a cross-sectional view taken along line IV, FIG. 5 is an explanatory view showing the positional relationship between the rotor and eight facing surfaces, and FIG. 6 is an exploded perspective view showing the relationship between the rotor and four yokes. (A), (b) and FIG. 8 are drive circuit diagrams for respectively driving four coils, and FIGS. 9 to 11 are diagrams for two-phase two-excitation, two-phase one-excitation, and one-two-phase excitation, respectively. Timing chart diagram, No. 12
FIGS. 13 and 14 are views similar to FIGS. 3 and 4 showing another embodiment of the present invention, and FIG. 14 is a view similar to FIG. 5 showing still another embodiment of the present invention. FIG. 15 is a schematic plan view showing a conventional stepping motor, and FIG. 16 is a view similar to FIG. 1 of a conventional example. 11 ... Stepping motor, 12 ... Casing, 13 ... Rotor, A1, A
2, B1, B2 ... Yoke, A1a, A1b, A2a, A2b, B1a, B1b, B2a, B2b ...
Yoke arm part, A1c, A1d, A2c, A2d, B1c, B1d, B2c, B2d ...
Opposing surface, LA1, LA2, LB1, LB2 ... coil.

Claims (1)

(57) [Scope of utility model registration request] 1. A rotor having a plurality of poles magnetized in the circumferential direction, the rotor having at least two yoke arms on each extension of one diameter of the rotor, and having the same shape.
A pair of yokes are arranged in the axial direction of the rotor, and phase difference is provided at positions symmetrical to each other about the extension line of the diameter. A stepping motor, in which the center line of the stepping motor is arranged at equal positions in the circumferential direction of the rotor.