JPS61128761A - Stepping motor - Google Patents

Abstract

PURPOSE:To reduce the size of a motor profile by providing a permanent magnet, a DC exciting coil and its magnetic path in a stator, and providing a drive coil in the magnetic path that a magnetic flux rounds about a rotor, thereby decreasing a drive current. CONSTITUTION:A stator 13 is provided around a rotor 11 in a stepping motor, and two salient-poles 13A, 13B are formed on the inner periphery. Stator teeth 13Aa, 13Ba and rotor teeth 11A are respectively formed on the outer peripheral surfaces of the poles 13a, 13b and the rotor 11. A permanent magnet 15 is associated with the left side stator 13C disposed between the poles 13A and 13B, and a drive coil 17 is wound on the right side. An exciting current is supplied from a terminal 19 in a direction for cancelling a magnetic flux by the magnet 15 to the coil 17. Thus, the poles 13A, 13B become a magnetic path for guiding a magnetic flux of the magnet 15 to the rotor 11, the stator right side magnetic path 13D becomes a roundabout magnetic path of the magnetic flux of the magnet 15 to rotate the rotor 11 by switching the two magnetic paths by energizing and deenergizing the coil 17.

Description

[Detailed description of the invention] [Industrial application field] This invention improves efficiency by reducing drive current.

The present invention relates to an improvement of a stepping motor that allows the outer shape of the motor to be made smaller.

[Conventional technology]

As an example of a conventional stepping motor, the structure of a mariable reluctance type multiphase cascade type stepping Tanabata is shown in FIG. In FIG. 2, (a) is a front view seen from the axial direction, and (b) is a side view thereof. This stepping motor has one phase, one
10 mm for each phase along the principal axis tK in stages.

10B... are arranged. 10 people for each phase, IOR・
As shown in Figure (3) of Wc2, the stator 14 of...
The stator annular part 14'B is formed so as to surround the rotor 20, and 14 protrusions 14R, 140, 14D are formed at equal intervals on the inner peripheral surface of the stator annular part 141, and the drive coil 16 is formed therein. 16R, 160°16D are wound on each. 16 drive coils.

168, 160, and 16D are connected in series and are excited by supplying current from terminal 18. Drive coil 16A, 1
When 68, 160, and 16D are excited.

14 salient poles each, 148, 140.14D alternately N grinding,
It is magnetized to the S pole, and a magnetic flux is generated as shown by the dotted line in FIG. 2(a).

The rotor 20 has a cylindrical shape. Stay salient pole 1
As shown in the enlarged view of the entrance part in FIG. 2(a), the stator teeth 14a and the rotor teeth 20a are made of cedar bark at the same pitch on the opposite sides of the rotor 20 and the rotor 20. Therefore, drive coils 14N, 14B, 14
0,14D1! : When excited, the rotor 20 stops at a position where the magnetic resistance is minimum, that is, a position where the stator teeth 14a and the coater teeth 20a match.

The stator 14 has each phase 104°108° parallel to the main axis t.
... are lined up, and the rotor teeth 14a are shaped at a predetermined helix angle a with respect to the main axis t, as shown in FIG. 2(b). Next, stator tooth 1
4a and the rotor teeth 20a, each phase 10&, 1
When the stator teeth 14a and rotor teeth 20 of the first phase 10 are facing each other correctly, the stator teeth 14 of the second phase 10B and the rotor teeth 20a are slightly shifted. ing. Therefore, the first
When 10 phases are excited and the second phase 10B is fully excited from the next state and switched to the next state, the rotor 20 moves to the position where the stator teeth 14a and coater teeth 20a are facing correctly in the second phase 10B.
rotates and stops. In this way, each phase is 10 A.
, 10 B, . . . by turning on and off in a predetermined order, the rotor 20 can be rotated by an arbitrary number of steps.

This variable reluctance type multiphase cascade type stepping motor has the following advantages.

■ By increasing the number of stages, the number of phases can be increased, and a motor with high torque and high resolution can be manufactured.

- Since the rotor 20 has an elongated shape, the inertia is small compared to the torque, and the response is good.

On the other hand, a drawback of this type is that it is inefficient because all the required magnetic flux is obtained by current.

Next, FIG. 3 shows an example of a conventional four-phase hybrid type stepping motor (a 9-type V type that combines a variable reluctance type and a permanent magnet type). (a) is a front view of the box seen from the axial direction, and (b) is a side f view of No. 7. As shown in FIG. 3(b), this stepping motor has 1
2 stages 22K with 2 stages each.

22B is at the bottom of the tank, and the first stage 22 has incoming phase and 0 phase.

In the K2 stage, B phase and C phase are placed at the bottom of the tank.

The rotor 26 includes a first stage rotor 26A and a second stage rotor 26A.
It is divided into two parts B and connected by a permanent magnet 28. By the way, the first stage rotor 26N is N! It was converted to 51fi,
$2 tier! : The lator 26B is magnetized to the S pole. The rotors 26N and 26B have rotor tooth bottoms.

In the first stage 22A, as shown in FIG. 3(a), the stator 30 has four protrusions 3ON, 308, 300° 30D, to which the stator 32A is driven.

32F+ and 320.32D are wound respectively.

The drive coils 32A and 320 are connected in series, and a current is supplied from the terminal 34. The drive coils 32B and 32D are connected in series and cover the entire C-phase drive coil, and a current is supplied from the terminal 36. The rotor teeth 26a and the stator teeth 30 are as shown in Fig. 3 (enlarged view of the entrance part in ai, enlarged view of part B), and when facing each other in the input phase (30 people, 300). The position is completely shifted in the C phase.The 22 people in the second stage are placed at the bottom of the tank in the same way as the 22 people in the first stage, and the B and D phases are covered with cedar bark.

Now, true 1 stage 22D phase input, O phase each drive coil 32 people, 3
28,320.32DK [When a current 't- is applied so as to be excited with the polarity shown in Figure 3 (,).

(In the C phase, the magnetic flux from the rotor 26k and the magnetic flux from the drive coils 32N and 320 are stronger and weaker, resulting in a strong magnetic force (enlarged view).On the other hand, in the C phase, they cancel each other out and are softer. (Enlarged view of CB section where magnetic force does not work). Therefore, the rotor 26 stops at a position where the rotor teeth 262 and the stator teeth 30a are opposite to each other upon entering the phase.

Next, the first stage 22 output is stopped, and the second stage 22
For the 8-phase, the full current is supplied so that the magnetic flux emitted from the motor 26B and the magnetic flux from the drive coil are strengthened, and for the D-phase, the Vct current is supplied so that they cancel each other out. For example, in the B phase, the rotor 26 stops at a position where the rotor teeth 26b and the stator teeth face each other.

Next, if the excitation of the second stage 22B is stopped and the 22 people in the first stage enter the phase, and the 0 phase is supplied with an electric current Rt- with the opposite polarity, the rotor teeth 261 and the stator teeth 30a will be connected in the O phase. The rotors 26 stop at opposing positions.

Then, stop excitation of 1W, 1 stage 22 input.

If the entire current is supplied to the B and D phases of the second stage 22FI with the polarity opposite to that described above, the rotor 26 will stop at a position where the rotor teeth 26m and the stator teeth 30i face each other in the D phase. In this way, the currents from the input phase to the D phase can be switched in a predetermined order, and the rotor 26t can be rotated an arbitrary number of steps.

In this hybrid stepping motor, a part of the necessary magnetic flux is obtained from the permanent magnet 28, so #
Compared to the variable reluctance type shown in Figure WC2, a larger torque can be obtained with the same current value, and the efficiency is good, but there are drawbacks such as zero order.

■ It is very difficult to make a multi-stage cascade type.
It is difficult to manufacture high-resolution, high-torque motors. That is, in the case shown in Fig. 2, it is possible to easily manufacture a motor with any number of stages by simply changing the torsion angle at of the rotor teeth 20a, but in the case shown in Fig. 3, a motor with an arbitrary number of stages can be easily manufactured, but in the case shown in Fig. Also, the hs stage type cannot be manufactured. For example, consider a four-stage field t.

The rotor teeth are difficult to round for each stage and cannot be integrated, which requires the same effort as manufacturing two-stage motors with two side sounds and adjusting the phase t of each rotor. In other words, as the number of zero stages increases, the difficulty of manufacturing increases dramatically, making it impractical.

■ Since the rotor 26 has a permanent magnet of 28t,
6 has a large weight and has a large outer diameter compared to its torque, resulting in large inertia and poor responsiveness.

[Problem that the invention seeks to solve]

This invention solves the drawbacks in the prior art,
Higher efficiency by reducing drive current, smaller motor size, etc.? The present invention aims to provide a stepping motor that makes it possible.

[Means to solve all problems]

This invention includes a permanent magnet in the stator of a stepping motor, a DC excitation coil (t7c), a magnetic path that guides the magnetic flux to the rotor, a magnetic path that detours the magnetic flux without passing it through the rotor, and a circuit in the circuit. The drive coil that generates the magnetomotive force is set to 4.

[Operation] According to the solution means of the present invention, when one current is passed through the drive coil of the detour to cancel the magnetic flux due to the permanent magnet and (11'c) the DC excitation coil, VC is connected to the permanent magnet and ('tfc). ) The magnetic flux of the DC excitation coil and the magnetic flux of the drive coil in the detour path 't-'fi: The magnetic flux passes through the rotor, the rotor becomes excited, and the supply of the current to the drive coil in the detour path is stopped. At this time, the magnetic flux of the permanent magnet and/or the DC excitation coil passes through the detour and does not pass through the rotor, so that the rotor is in a non-excited state. Therefore, in the excited state, the magnetic flux of the permanent magnets and the magnetic flux of the drive coil are added together to drive the rotor, so the current in the drive coil can be reduced. Furthermore, even after using a DC excitation coil, there is no need to turn on and off the current supplied to the DC excitation winding.

All you need to do is connect the DC excitation windings of each phase in series and constantly pass a constant current, so the current as a whole is lower than that of a conventional VR type motor in the case of a multi-phase motor.

Moreover, manufacturing of the drive circuit becomes easy.

[Embodiment 1] The Kt diagram is a diagram showing a basic embodiment of the present invention, and is an axial view of one stage of a stepping tanabata with one phase and one stage, multi-stage cascade connection and groove bottom. It is.

In this stepping motor, the stator 13 is released so as to press against the rotor 11, and the inner periphery of the stator 13 has two butts 13 disposed at opposite positions sandwiching the rotor 11t.
Hmm, 13B has been released.

The outer peripheral surface of the rotor 11 and the protrusion ff facing the rotor 11
1laA and 13FlO planes are enlarged views of the middle part of Figure 1.

As shown in the enlarged view of part B, the rotor teeth 11 and stator teeth 13Aa, 13Ba are each exposed.

13 people, 13Btl - stator part 1 on the left side
30 has a permanent magnet 15 incorporated therein.

Further, a drive coil 17 is wound around the right stator portion 13D. A current is supplied to the drive coil 17 from the terminal 19 so that the drive coil 17 is excited in a direction that cancels out the magnetic flux generated by the permanent magnet 15 .

According to the configuration shown in Fig. 1, when no current is supplied to the drive coil 17, the magnetic flux generated by the permanent magnet 15 is mostly directed to the outer circumference of the stator, as shown by the two-dot chain line 21 in Fig. 1. 130. 13Dyfr: Passed, the salient poles 13A and 13B do not pass through the rotor 11 just a little. Therefore, the rotor 11 is not strongly attracted. On the other hand, when the entire current is supplied to the drive coil 17, the magnetic flux generated by the drive coil 17 is generated in a direction that cancels the magnetic flux generated by the rotor 11.

The magnetic flux caused by the drive coil 17 and the magnetic flux caused by the permanent magnet 15 are as shown by dashed lines 23 and 25 in the figure, respectively.
Both pass through a route from the 13 salient poles to the salient pole 13F+ via the rotor 11. therefore.

The rotor 11 is strongly attracted and stops at a position where the rotor teeth 11a and the stator teeth 13Na and 13Ra coincide.

Thus, by turning the current on and off.

The magnetic flux passing through the rotor 11t can be turned on and off. In other words, the total number of people in Figure 1 is 13 people.

13B is a magnetic path that guides the magnetic flux of the permanent magnet 15 to the rotor 11, and the stator right side portion 13D is a magnetic path that detours the magnetic flux of the permanent magnet 15, and the next drive coil 170 disposed in this detour is turned on and off.

The two magnetic paths can be switched.

According to the groove bottom in Fig. 1, when the magnetic flux is supplied, in addition to the magnetic flux from the winding 17, the magnetic flux acting on the permanent magnet 15 also acts, so a stronger torque is generated compared to excitation by only one winding 170. can get.

The operation for one stage is performed as described above.

The other stages are left open in the same way, and the phase relationship between the stator teeth and rotor teeth in each stage is set to be slightly shifted for each stage, and the drive coils of each stage are sequentially and alternately excited. The rotor can be rotated by any number of steps.

Here, an explanation will be given using an operating t-magnetic circuit of 0 or more.

FIG. 4 shows the rotor 11 and stator 13 of FIG. 1 in a magnetic circuit. Each symbol in Figure 1 has the following meaning.

E: Magnetomotive force Eo due to permanent magnet 15: Magnetomotive force Rg due to drive filter 17: Magnetic resistance rl of the gap between rotor 11 and stator 13: Magnetic resistance r2 of left stator portion 130: Magnetic resistance of right stator portion 13D In such a magnetic circuit, approximately the same law as in an electric circuit is violated, and the magnetic flux is divided by the magnetomotive force t-magnetic resistance as in the case of the current field.

Here, when no current flows through the drive coil 17, EC=O, and 1° of the magnetic flux of the permanent magnet 15 corresponds to the magnetic resistance of rl, Rg, and r2f in parallel, plus t.

becomes.

M*, Rgt - magnetic flux ig and r2 total magnetic flux i
Because c is divided by the reciprocal ratio of 1p1t''Rg and r2.

'g='p1×(2) Rg+r. Here, in the embodiment shown in FIG. 1, the stator 13 is left-right symmetrical and can be considered as r1'', r2, so r
= r 1 = r 2.

Furthermore, since 1 normal Rg)) r, the formula 11 is.

So, equation (2) and equation (3) are as follows.

i g #O IC #Ip1. In other words, the magnetic flux due to the permanent magnet 15! , 1 mostly passes through the stator right side portion 13D, which is a detour, and is a protrusion 13^ which is a supply path to the rotor 11.

13B, therefore e2-11 is not strongly attracted to stator 13. The above corresponds to the case where this phase is de-energized.

Next, when a current is supplied to the coil 17 so that fusion=gp, the circuit in Fig. 4 becomes symmetrical, so
Ig and lp2, respectively.

E.

becomes. That is, the magnetic fluxes 1p2 and 1 due to the permanent magnet 15
The magnetic flux 10 from the winding 17 is added and guided to the rotor 11, and the rotor 1] has rotor teeth 111 and stator teeth 13A.
The excitation state of this phase is 0 or more, which is rotated to a position # where a and 13Ba match.

In addition, when actually designing, the magnetomotive force E,
1! Determine r.

In addition, in the case of non-excitation, if r cannot be ignored with respect to Rg due to the structure of the motor, the direction of the current supplied to the coil 17 is reversed, and the direction of EC in FIG. 4 is reversed. All you have to do is find the conditional money that makes ig=o. This result is g,
= -g, and a current of the same magnitude as in the case of excitation flows in the opposite direction.

[Embodiment 2] Based on the embodiment shown in Fig. 1, an embodiment further developed is shown in Fig. 5.
It is a tn72 item for 2 pieces each. In Figure 5, (a
) is a front view viewed from the axial direction, and (b) is a side view thereof.

This stepping motor is constructed by connecting a plurality of stages (40 mm, 40 B, . . . ) of l-phase, single-stage rotor and stator combinations in series as shown in FIG. 5(b).

The stator 42 of each phase has 40 people, 40B-..., and the stator 42 of the fifth (
As shown in 1), the stator annular portion 42 is formed so as to surround the rotor 44, and the stator annular portion 42 is formed so as to surround the rotor 44. Four protrusions 42B protruding at equal intervals on the inner peripheral surface of 42 people.
, 420.42D, 42]1! It has an i. The outer peripheral surface of the coater 44 and the salient poles 42B, 420 .
On the sides of 42D and 42B.

The rotor teeth and stator teeth (both not shown) are each released. A portion 42Ab of the stator annular portion 42 located between the projections ff1420 and 42D and a stator annular portion located between the butts 42E and 42B. Drive coils 46 and 48 are wound around the portions 42Ad of 42, respectively. Also, FF1
A portion 42a of the stator ring 's42 located between 42B and 420 and a salient pole 42D.

Permanent magnets 50, 52 are respectively inserted into the sections 42cK of the stator annular portion 42 located between the stator rings 42B and 42B. Drive coils 46, 48 are connected in one row,
Current is supplied from terminal 53.

It is excited in a direction that cancels the magnetic flux generated by the permanent magnets 50 and 52.

According to the above groove bottom, [When the moving coils 46.48 are not excited, the magnetic flux of the permanent magnets 50.52 is mostly transferred to the stator annular portion 42, as shown by the double-dashed arrow 56.
Therefore, the rotor 44 is only slightly guided. Therefore, the rotor 44 is not strongly attracted, whereas when the drive coil 46, 48 is energized,
The magnetic flux due to the drive coil 46.48 is the permanent magnet 50.52
The permanent magnet 50
．． The magnetic flux 52 passes through the rotor 44t as shown by a dashed-dotted arrow 58. Also, drive coil 46.48
As shown by the dashed line arrow 60, the magnetic flux of the rotor 44
All passes. Therefore, the rotor 44 stops at a position where the rotor teeth and stator teeth match. When it gets wet, in addition to the magnetic flux from the drive coil 46.48, the magnetic flux from the permanent magnet 50.52 passes through the rotor 44, so the drive coil 46.48
Larger torque can be obtained compared to excitation only.

Thus, by turning on and off the current supplied to the drive coils 46 and 48, the magnetic flux passing through the rotor 44 can be turned on and off. In other words, the bottom of the tank in Figure 5 is
The prongs 142c and 42B form a magnetic path that guides the magnetic flux of the permanent magnet 50 to the rotor 44.

The salient poles 42D and 42g transfer the magnetic flux of the permanent magnet 52 to the rotor 44.
It becomes a magnetic path that leads to. ``Furthermore, the stator annular portion 42 serves as a magnetic path that detours the magnetic flux of the permanent magnets 50.52, and these magnetic paths are switched by turning on and off the ftK moving coils 46, 48 disposed in this detour.

Above, we have explained the first stage of 40 pieces, but other stages of 40
0B, . . . are also bottomed out in the same way. As shown in FIG. 5(b), the stators of 40 stators and 40B of each stage are arranged so as to be shifted by 90 degrees from each other to prevent the moving coils 46 and 48 from colliding with each other.

The 44 rotor teeth are connected to the main shaft t as shown in Fig. 5 (b3).
A predetermined twist angle α is applied to the shaft.

As a result, the phase relationship between the 44 rotor teeth of each stage and the stator teeth is gradually shifted. Be friends, each step 4
By sequentially and alternately exciting 0 & , 40 B, . . . , the rotor 44 can be rotated by an arbitrary number of steps.

[Embodiment 3] In the second embodiment, a permanent magnet with 92 teeth in one stage and two drive coils are used, but it is also possible to use a larger number of teeth. Figure 6 shows three permanent magnets 6 as an example.
0.62.64 and 3 coils 66.68, 70t-
It's something you should use. Drive coil 66.68.
70 is excited in a direction that cancels the magnetic flux produced by the permanent magnets 60, 62, and 64. When no current is being supplied to the drive coils 66, 68, 70, the magnetic flux of the permanent magnets 60, 62, 64 is directed to the stator beak 74 as shown by the two-dot chain line 72.
t-wise, the rotor 76 is not strongly attracted. On the other hand, when current is supplied to the drive coils 66, 68, 70, the drive coils 66, 68.

Since the magnetic flux of 70 is generated in a direction that cancels the magnetic flux of permanent magnets 60, 62, 64, permanent magnets 60, 62.

The magnetic flux of 64 and the magnetic flux of drive coils 66, 68, and 70 are shown by dashed lines 78, 80, respectively.

It is guided to the rotor 76 through the stator lobes 82, 84, 86, 88, 90, 92. In response, the rotor 76 is attracted to the stator salient poles, and the rotor 76 stops at a position where the rotor teeth and stator teeth match. Accordingly, the combination of stator and rotor 76 is arranged in multiple stages in the axial direction, the phase relationship between the stator teeth and rotor teeth is slightly shifted for each phase, and the drive coils of each phase are sequentially and alternately arranged. By excitation, the rotor 76 can be rotated by an arbitrary number of steps.

[Example 4] In the embodiment shown in FIG. 1, there are 13 salient stator poles.

A permanent magnet 1 is placed in the annular portion 130 on the left side of the 13B.
5t- was installed, and the winding 17 was applied to the right annular portion 13D, and as shown in FIG.

These are amazing! Rotor 941r- placed between 96.98.

A permanent magnet 100 is installed in the center of the stator 101,
The same effect can be obtained by installing the drive coil 102 on the right side of the stator 101. In FIG. 7, a two-dot chain line 104 indicates the flow of magnetic flux due to the permanent magnet 100 when the drive coil 102t-vJ is not magnetized.
t-th order, one point g4 line 106°108 = exit, drive coil 1
The flow of magnetic flux due to the permanent magnet 100 and the flow of magnetic flux due to the drive coil 102 are respectively shown in FIG. That is, [when no current is supplied to the moving coil 102 t, most of the magnetic flux from the permanent magnet 100 passes through the detour on the right side of the stator, and e! - It is hardly guided to the data 94. Also,! When a current is applied to the drive coil 102, the magnetic flux generated by the drive coil 102 is caused by the permanent magnet 10.
The magnetic flux generated by the drive coil 102 and the magnetic flux generated by the permanent magnet 100 are both guided to the rotor 94 because the magnetic flux generated by the drive coil 102 and the magnetic flux generated by the permanent magnet 100 are generated in a direction that cancels out the magnetic flux caused by the magnetic flux. In this way, the O phase is excited by turning on and off the current to the drive coil 102.

Non-excited milling is performed.

[Example 5] The example shown in Fig. 8 is as follows! The arrangement of the permanent magnet 100 and the drive coil 102 in FIG. 7 is changed. When no current is being supplied to the drive coil 102, the permanent magnet 10
0 magnetic flux is detoured as shown by the two-dot chain line 110 and is not guided to the rotor 94, the drive coil 1021C! fit
- When supplied, the magnetic flux of the drive coil 102 is
Since all of the magnetic fluxes at zero are generated in the direction of extinguishing the light, these magnetic fluxes are both guided to the rotor 94 as shown by dashed lines 112 and 114, respectively. As a result, an operation similar to that of FIG. 7 is obtained.

[Example 6] The embodiment shown in FIG. 9 is based on the embodiment shown in FIG.

This was further developed to have two phase bottoms in one stage. The stator is surrounded by four parts 13
It is divided into 0, 132, 134, and 136 parts. As in the embodiment of FIG.
1 (magnetic path).

poles 130A, 130B) and a detour 1300 of the a1 bundle. The other stator parts 132.134136 are similarly constructed. Each stator part 130.132
, detour 1300.1320 at 134.136,
At 1340.1360.

Drive coils 140, 142, 144, and 146 are wound respectively. The drive coils 140 and 144 are connected in series to constitute a phase drive coil, and a current is supplied from a terminal 148 to excite the coils in a direction that cancels out the magnetic flux generated by the permanent magnets 133 and 137.

The drive coils 142 and 146 are connected in series so that all the B-phase O drive coils are connected to each other, and a current is supplied from a terminal 150 to excite the drive coils in a direction that cancels out the magnetic flux generated by the permanent magnets 135 and 139.

When no current is supplied to the drive coils 140.142.144.146, each permanent magnet 133°135.13
The magnetic flux of 7,139 is detoured to 130 as shown by the two-dot chain line.
0,1320,1340°1360, rotor 13
1 is not excited.

Drive coils 140, 142, 144. When a current is supplied to L46, its magnetic flux is a permanent magnet 133°135.13
7,139, the magnetic fluxes of the drive coils 140, 142, 144° 146 and the magnetic fluxes of the permanent magnets 133, 135, 137° 139 both pass through the =-ta 131 as shown by the dashed line. and rotor 1
31 is excited.

The relationship between the rotor teeth and stator teeth is shown in an enlarged view of the entrance.

Shown in the enlarged view of part B: There is a 6-phase shift from the urchin entering phase.

Then, by alternately switching the input phase, the B phase, and the phases of the other stages and energizing them, the 10-tar 131 can be rotated a predetermined number of steps.

[Embodiment 7] In each of the above embodiments, a permanent magnet is used, but a DC excitation coil may be used instead.

As an example, FIG. 10 shows a case where the permanent magnet 15 in the embodiment shown in FIG. One current is always supplied to the DC excitation coil 120 so that it is excited with the polarity shown in the figure. I current excitation when no current is supplied to the drive coil 17;
Most of the magnetic flux of the coil 120 passes through a detour, as shown by a two-dot chain line 122, and is not guided to the rotor 11. coil 1
When current is supplied to the coil 17') t1i flux is generated in a direction that cancels the magnetic flux of the DC excitation coil 120.

These magnetic fluxes pass together through the rotor 11t, as shown by dashed lines 124 and 126. This j: coil 17
By turning on and off the current supplied to the phase, it is possible to create an energized or de-energized state for this phase. [Embodiment 8] In each of the above embodiments, a permanent magnet or a DC excitation coil was used, but these can also be used in combination.

[Effect of idea]

As explained above, according to the present invention, the following effects can be obtained.

■ By obtaining the necessary magnetic flux from a permanent magnet.

In order to produce the same torque, less current is needed to be supplied to the drive coil than with conventional models. Also.

As a result, manufacturing of the drive circuit becomes easier.

■ Because the number of windings is smaller than the conventional one.

It is possible to reduce the size.

■ Unlike the conventional hybrid type (Figure 3), the rotor does not have a permanent magnet, so the rotor weight and outer diameter can be reduced, the inertia of the rotor can be reduced, and a multi-stage cascade type can be used. .

■ Even when using DC excitation coils instead of permanent magnets, there is no need to turn on and off the current supplied to the DC excitation windings, so the DC excitation windings of each phase can be connected in series (connected to keep the current constant at all times). All you need to do is pass current, and in the case of a polyphase motor, the overall current is smaller compared to conventional DVFL type motors.
Moreover, there is an effect that manufacturing of the drive circuit becomes easy.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a basic embodiment of this invention;
FIG. FIG. 2 is a diagram showing a conventional palliable reluctance type multiphase cascade type stepping Tanabata. (a) is a front view seen from the Fi axis direction, and (b) is a side view thereof. Figure WJ3 is a diagram showing a conventional hybrid stepping motor, and (2) is a front view seen from the axial direction. (b) is its side view. Figure K4 is a diagram showing the entire magnetic circuit of the embodiment of Figure 1. 1M5 to IJIclO are diagrams showing other embodiments of the present invention, respectively. 13.14,30,42,74.101...Stator, 15,50,60,62. f54, 100°133.
135,137,139...Permanent magnet. 16 people, 168, 160.16D, 17.32 people. 328.320,320,46,48,60°68.7
0,102,140,142,144°146... Drive coil, 120... DC excitation coil.

Claims (1)

[Claims] A permanent magnet and/or a DC excitation coil, a magnetic path that guides the magnetic flux of the permanent magnet and/or DC excitation coil to the rotor, and a magnetic path that detours the magnetic flux of the permanent magnet and/or DC excitation coil without passing it through the rotor. 1. A stepping motor, characterized in that a stator is provided with a magnetic path that generates a magnetomotive force in the detour magnetic path, and a drive coil that generates a magnetomotive force in the detour magnetic path.