JPH0635657Y2 - Stepping motor - Google Patents

Description

The present invention relates to a stepping motor, and more particularly to a hybrid type stepping motor capable of detecting the position of a rotor with an inexpensive and simple structure.

[Prior Art] Since a hybrid type stepping motor has a unique high-precision positioning function, it is drive-controlled by inexpensive open-loop control (control without feedback control) for normal use. In applications where vibration and out-of-step prevention, non-vibration stop, acceleration / deceleration / stop with high-speed response, etc. are required, closed-loop control (feedback control performed based on information on the rotor's rotational position and speed) ) Drive control.

Conventionally, in the case of performing closed loop control, an optical or magnetic encoder has been used to obtain information on the rotational position and speed of the rotor. If an encoder is used, information on the position and speed of the rotor can be obtained with high accuracy, but the price of the encoder will be several times higher than the price of the main body of the stepping motor, and the price of the motor will be extremely high. was there. Further, when an encoder is used, a space for installing the encoder is required, which causes a problem that the length dimension of the motor becomes large.

Therefore, in a hybrid type stepping motor, a counter electromotive voltage is generated in the excitation winding wound around the stator magnetic poles as the rotor rotates, and this counter electromotive voltage includes rotor position information. Focusing on this fact, a technique has been proposed in which the back electromotive force detection winding is wound around the stator magnetic pole outside the excitation winding, and the rotor position information is obtained from this back electromotive force detection winding. It was This technique is shown in FIGS. 2A and 2B.
An example for implementation with a 16 pole, two phase hybrid stepping motor is shown. The figure shows only a schematic configuration of the stator 1 and the rotor 2 (pole teeth are not shown). In this conventional example, a bifilar winding, that is, two winding conductors are simultaneously wound around a magnetic pole, one winding conductor is used as an excitation winding, and the other winding conductor is used as a back electromotive force detection winding. ing. FIG. 2A shows the winding structure of the first phase, and FIG. 2B shows the winding structure of the second phase. In FIG. 2A, L ₁ is a first phase bifilar winding, and this winding L ₁ is a magnetic pole protruding from the yoke 3.
The magnetic poles are wound around the first magnetic pole group P ₁ , P ₃ ... P _{15 so as} to be alternately magnetized to have opposite polarities. Of the bifilar winding L _1, the winding L ₁₁ having terminals A ₁₁ and A ₁₂ is used as the first phase exciting winding, and the winding L ₁₂ having terminals F ₁₁ and F ₁₂ is used for the first phase. It is used as a back electromotive force detection winding. The second phase winding structure shown in FIG. 2B is also configured in the same manner as the structure of FIG. 2A. In FIG. 2B, L ₂ is a second-phase bifilar winding, and this winding L ₂ is the magnetic poles P ₂ and P ₄ forming the second magnetic pole group.
… Wound on P ₁₆ . The winding L ₂₁ is used as a second phase excitation winding, and the winding L ₂₂ is used as a back electromotive force detection winding for the second phase.

However, when the bifilar winding is used, the two bifilar windings L ₁₁ and L ₁₂ have a winding ratio of about 1
Therefore, the voltage signal induced in the reverse voltage detection winding by the mutual induction between the two windings interferes when this signal is used for position detection or speed detection. There is a problem that a voltage component that becomes Therefore, in the conventional technique, in order to remove unnecessary voltage components, as shown in the circuit for one phase in FIG. 3, the primary winding t ₁ and the secondary winding are wound on the windings L ₁₁ and L ₁₂ . A transformer T in which the lines t ₂ are connected in series is used. The detection signal V ₁ actually used as the position information of the rotor has a value of V ₁₁ -V ₁₂ . The relationship between the detection signal V ₁ obtained from the first-phase back electromotive force detection winding L ₁₂ and the detection signal V ₂ obtained from the second-phase back electromotive voltage detection winding L ₂₂ is shown in FIG. As shown in, the 90 ° phases have different relationships.

[Problems to be Solved by the Invention] As described above, when the back electromotive force detection winding wound by the bifilar winding is used, an unnecessary voltage component is induced in the back electromotive force detection winding. There is a problem that the output of the back electromotive force detection winding cannot be used as it is, and a separate transformer T is required as in the example of FIG. Further, in the case of using the bifilar winding, in order to secure a sufficient winding space for the excitation winding, there is no choice but to increase the gap between the magnetic poles, which causes a problem of increasing the size of the motor. . Furthermore, if you try to wind the winding without enlarging the motor,
There are also problems that the number of turns of the excitation winding is reduced and the winding work is troublesome.

Further, in the conventional stepping motor, when the exciting current is supplied to the exciting windings L ₁₁ and L ₂₁ by the chopper drive, the current change on the exciting winding side becomes large.
In addition to the configuration shown in FIG. 3, chopping noise is induced in the voltage output from the back electromotive force detection winding, and a complex low-pass filter is further required to remove this noise. There was also a problem that became very complicated.

An object of the present invention is to provide a stepping motor that can detect a back electromotive force with a low cost and a simple structure.

[Means for Solving Problems] The present invention is directed to a stepping motor having a rotor 2 and a stator 1. The rotor 2 is provided with a plurality of rotor-side pole teeth 5, the plurality of rotor-side pole teeth 5 are arranged at a predetermined interval, and are magnetized to have a predetermined polarity. The stator 1 is m × n (where m and n are positive integers of 2 or more)
Stator side magnetic poles (P _{1 to} P ₁₆ ) and m phase excitation windings (L ₁₁ , L
₂₁ ) and m phase back electromotive force detection windings (L ₁₀ , L ₂₀ ). Each of the stator side magnetic poles (P _{1 to} P ₁₆ ) is arranged at a predetermined interval, has a plurality of stator side pole teeth 4 facing the rotor side pole teeth 5, and has m phases. Corresponding to the excitation windings (L ₁₁ , L ₂₁ ), m magnetic pole groups (P ₁ , P ₃ , ... P ₁₅ ; P ₂ ,
P ₄ , ... P ₁₆ ). The back electromotive force detection windings (L ₁₀ , L ₂₀ ) for m phases are respectively associated with corresponding magnetic pole groups (P ₁ , P ₃ , ...
At least one of the magnetic poles (P ₁₅ ; P ₂ , P ₄ , ... P ₁₆ ) (P
₂ , P ₁₅ ). Excitation winding for m phases (L ₁₁ , L ₂₁ )
Are magnetic poles (P ₁ , P ₃ , ...) In which the back electromotive force detection windings (L ₁₀ , L ₂₀ ) are not wound among the magnetic poles of the corresponding magnetic pole groups.
It is wound around P ₁₃ ; P ₄ , ... P ₁₆ ).

[Operation of the Invention] In the present invention, the back electromotive force detection winding corresponding to each excitation winding is wound around at least one magnetic pole of each magnetic pole group in addition to the excitation winding. No unnecessary voltage component or noise is induced in the power winding. When the detection winding is wound around one magnetic pole for the same number of turns as when the conventional bifilar winding shown in Fig. 2 is used, a 1 / n back electromotive force is induced in the detection winding. However, a detection signal of a desired voltage can be obtained by appropriately determining the number of magnetic poles around which the detection winding is wound, the wire diameter of the detection winding, and the number of windings.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

1A and 1B show two-phase excitation windings L ₁₁ and L ₁₂ , respectively.
The winding state of each phase of the hybrid type stepping motor provided with is shown. The stator 1 of the stepping motor of this embodiment is made of a laminated steel plate, and 16 poles P _{1 to} P ₁₆ are provided on a cylindrical yoke 3 so as to project at predetermined intervals. Each magnetic pole
Two stator-side pole teeth 4 are provided at predetermined pitches on the magnetic pole surfaces P _{1 to} P ₁₆ .

Since the rotor 2 has a well-known rotor structure, it is not shown in detail, but a cylindrical permanent magnet magnetized in the longitudinal direction is arranged in the center of the rotor 2. Two soft magnetic bodies having rotor-side pole teeth continuous at a predetermined pitch on the outer circumference on both sides in the longitudinal direction are attached so as to sandwich the permanent magnet. The two soft magnetic bodies are made of a layered steel sheet or a sintered alloy, and the two soft magnetic bodies are magnetized to have N poles and S poles, and the pole teeth of the two soft magnetic bodies are displaced by a half pitch. Has been. It should be noted that the rotor 2 in FIG. 1A is roughly a part of the pole teeth 5 of one soft magnetic material.
Only shown. In this embodiment, each soft magnetic material
The 50 pole teeth 5 are motorized, and when excited by the one-phase excitation method, one step is performed at a step angle of 1.8 °.

In the present embodiment, as shown in FIG. 1A, the first-phase excitation winding L ₁₁ constitutes a first magnetic pole group divided for winding the first-phase excitation winding. The magnetic poles P ₁ , P _3, ... P ₁₅ are wound around the magnetic poles P ₁ , P _3, ... P ₁₃ excluding the magnetic pole P ₁₅ .
The first back electromotive force detection winding L ₁₀ corresponding to the first phase is wound around the remaining magnetic pole P ₁₅ of the first magnetic pole group. The back electromotive force detection winding L ₁₀ changes according to the positional relationship between the stator-side pole teeth 4 and the rotor-side pole teeth 5 of the magnetic pole P ₁₅ due to the change in the magnetic flux generated by the rotation of the rotor 2. A back electromotive force is induced.

The principle that the back electromotive force is induced is based on the inductive action as in the conventional motor. The magnetic flux coming out of the magnet provided in the rotor 2 and interlinking with the first counter electromotive voltage detection winding L ₁₀ changes the positional relationship between the stator-side pole teeth 4 and the rotor-side pole teeth 5, that is, It changes according to the change in the facing area. As a result, a counter electromotive voltage is induced in the counter electromotive voltage detection winding L ₁₀ according to the positional relationship between the stator-side pole teeth 4 and the rotor-side pole teeth 5 of the magnetic pole P ₁₅ .

As shown in FIG. 1B, the second phase excitation winding L
₂₁ is one of the magnetic poles P ₂ , P ₄ ... P ₁₆ that constitute the second magnetic pole group.
It is wound around the magnetic poles P ₄ , P ₆ ... P ₁₆ excluding the _two magnetic poles P ₂ .
The second back electromotive force detection winding L ₂₀ corresponding to the second phase is wound around the remaining magnetic pole P ₂ of the second magnetic pole group.
Also in the second counter electromotive voltage detection winding L ₂₀ , according to the positional relationship between the stator-side pole teeth 4 and the rotor-side pole teeth 5 of the magnetic pole P ₂ ,
A back electromotive force is induced. However, the stator side pole teeth 4 of the magnetic pole P ₂
Since the positional relationship between the rotor-side pole teeth 5 and the rotor-side pole teeth 5 is different from the positional relationship between the stator-side pole teeth 4 and the rotor-side pole teeth 5 of the magnetic pole P ₁₅ , the first back electromotive force detection winding The voltages induced on the line L ₁₀ and the second counter electromotive voltage detection winding L ₂₀ are not in phase.
In this embodiment, the voltage induced in the first back electromotive force detection winding L ₁₀ and the second back electromotive voltage detection winding L ₂₀ is the same as that of the conventional one shown in FIG. The 90 ° phase difference is the same as the phase relationship between the output V ₁ and the output V ₂ of the device. Then, one cycle of the output waveform corresponds to one pitch of the rotor-side magnetic poles 5. Therefore, as in the conventional case, the outputs of the two counter electromotive voltage detection windings can be used as a signal indicating the position of the stepping motor, or can be used as they are as a speed signal.

When the detection winding is wound around one magnetic pole for the same number of turns as in the case of using the conventional bifilar winding shown in FIG. 2, the counter electromotive voltage of 1 / n is smaller than that of the conventional one. Although induced in the detection winding, a detection signal of a desired voltage can be obtained by appropriately determining the number of magnetic poles around which the detection winding is wound, the wire diameter of the detection winding, and the number of windings. . After increasing the number of magnetic poles per phase as in the present embodiment, a back electromotive force detection winding corresponding to each excitation winding is wound around one magnetic pole of each magnetic pole group in addition to the excitation winding. With this structure, the nonuniformity of the radial magnetic field balance caused by the independent provision of the back electromotive force detection winding can be reduced to the extent that it does not hinder the step of the rotor. The number of magnetic poles per phase is not limited to that in the embodiment, and may be appropriately selected so that the step of the rotor is not hindered.

In the above embodiment, one of the magnetic poles forming the first and second magnetic pole groups is wound with the counter electromotive voltage detection winding. However, when the number of magnetic poles is large, the counter electromotive voltage is further increased. The output voltage can be increased by increasing the number of magnetic poles around which the detection winding is wound. For example, in the above embodiment, the magnetic pole P
The first back electromotive force detection winding L ₁₀ is also wound on the magnetic pole P ₇ symmetrical to the magnetic pole ₁₅ , and also on the magnetic pole P ₁₀ symmetrical to the magnetic pole P ₂ . Second counter electromotive voltage detection winding L ₁₀
The magnetic balance can be made good by wrapping. When the back electromotive force detection winding is wound around a plurality of magnetic poles in series, it is preferable to select the magnetic pole to be wound in consideration of magnetic balance.

In the above embodiment has been wound around first and second back electromotive force detection winding L ₁₀ and L ₂₀ in the pole P ₁₅ and the pole P ₂ apart, for example adjacent to the pole P ₁₅ pole By winding the second counter electromotive voltage detection winding L ₂₀ around P ₁₆ , there is an advantage that the winding terminal can be easily pulled out to the outside.

Further, in the above embodiment, the stepping motor having the two-phase exciting windings has been described, but it goes without saying that the present invention can be applied to the stepping motor having the four-phase exciting coil and the five-phase exciting winding. is there.

Further, in the above embodiment, the hybrid type stepping motor in which the permanent magnet is provided on the rotor side has been described, but the present invention is a hybrid type stepping motor having another known configuration in which the permanent magnet is provided on the stator side. Can also be applied to.

[Advantages of the Invention] According to the present invention, since the back electromotive force detection winding corresponding to each phase is wound around at least one magnetic pole of each magnetic pole group in addition to the excitation winding, the conventional transformation is performed. It is possible to detect a counter electromotive voltage that does not include unnecessary voltage components or large noise with a simple configuration without requiring a device or a complicated filter.

[Brief description of drawings]

1A and 1B are schematic views showing winding states of windings of respective phases when the present invention is applied to a hybrid type stepping motor, and FIGS. 2A and 2B are windings of respective phases of a conventional stepping motor. Fig. 3 is a schematic diagram showing the winding state of each wire, Fig. 3 is a circuit diagram showing the wiring of a conventional motor, and Fig. 4 is a third diagram.
It is a wave form diagram which shows the waveform of the back electromotive voltage obtained from the conventional motor of the circuit structure shown in the figure. 1 ...... stator 2 ...... rotor, 3 ...... yoke, 4 ...... stator side teeth, 5 ...... rotor side teeth, P ₁ to P ₁₆ ...... pole, A
₁₁ , A ₁₂ ...... Terminal, F ₁₁ , F ₁₂ ...... Terminal, L ₁ ...... First phase bifilar winding, L ₂ ...... Second phase bifilar winding, L
₁₀ ...... 1st back electromotive voltage detection winding, L ₂₀ ...... 2nd back electromotive voltage detection winding, L ₁₁ 1st phase excitation winding, L ₁₂ ...... 1st phase back electromotive voltage Detection winding, L ₂₁ ...... Second phase excitation winding, L ₂₂
...... Second phase back electromotive force detection winding, P _{1 to} P ₁₆ ...... Magnetic pole,
T ...... transformer, t ₁ ...... primary winding, t ₂ ...... secondary winding.

Claims (2)

[Scope of utility model registration request] 1. A stepping motor having a rotor (2) and a stator (1), wherein the rotor (2) comprises a plurality of rotor side pole teeth (5) and a plurality of rotor sides. The pole teeth (5) are arranged at a predetermined interval,
Also, the stator (1) is magnetized to a predetermined polarity, and the stator (1) has m × n (where m and n are positive integers of 2 or more) stator-side magnetic poles (P _{1 to} P ₁₆ ) and m phases. Excitation winding (L ₁₁ , L ₂₁ ) and m-phase back electromotive force detection winding (L ₁₀ , L ₂₀ )
And each of the stator side magnetic poles (P _{1 to} P ₁₆ ) is arranged with a predetermined interval, and has a plurality of stator side pole teeth (4) facing the rotor side pole teeth (5). Existence winding for m phases (L
₁₁ , L ₂₁ ) corresponding to m magnetic pole groups (P ₁ , P ₃ , ... P ₁₅ ; P ₂ , P ₄ ,
… P ₁₆ ) and the m-phase back electromotive force detection windings (L ₁₀ , L ₂₀ ) respectively correspond to the corresponding magnetic pole groups (P ₁ , P ₃ , ... P ₁₅ ; P ₂ , P ₄ , ... P ₁₆ ) is wound around at least one of the magnetic poles (P ₂ , P ₁₅ ), and the m-phase excitation windings (L ₁₁ , L ₂₁ ) are among the magnetic poles of the corresponding magnetic pole groups. The stepping motor is wound around the magnetic poles (P ₁ , P ₃ , ... P ₁₃ ; P ₄ , ... P ₁₆ ) where the back electromotive force detection windings (L ₁₀ , L ₂₀ ) are not wound. 2. A winding for detecting back electromotive force for m phases (L ₁₀ , L ₂₀ ).
Are respectively wound around one magnetic pole, and these magnetic poles are located adjacent to each other. The stepping motor according to claim 1 of the utility model.