JPS62196060A - Stepping motor - Google Patents

Abstract

PURPOSE:To increase the number of steps by one rotational frequency, by combining two magnetic pole plates provided alternately with connected sections with a plurality of teeth at an equal pitch and elimination sections with a plurality of eliminated teeth, with each other, to form a magnetic pole core. CONSTITUTION:A stepping motor in two-phase system is composed of a housing, a stator core, a rotor, and the like. Four respective magnetic pole plates 33-36 composing the stator core are formed to be arranged, alternately with elimination sections 41 eliminating three teeth from a plurality of teeth arranged at equal intervals on the inner periphery, and with connected sections 40 with two teeth 37 left. The magnetic pole plates 33, 34 are phase-shifted by 5/2 pitch to be combined with each other so that the connected sections 40 may be respectively inserted into the elimination sections 41. Then, in comparison with the width of the teeth, the pitch between the teeth can be diminished, and the step angle can be diminished.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stepping motor, and particularly to a magnetic pole structure that can minimize the step angle.

[Conventional technology]

Figure Iio is a sectional view showing a conventional two-phase stepping motor, and Figure 11 is an exploded perspective view.

A rotor shaft 4 is rotatably supported by a bearing 2.3 fixed to the housing 1. A cylindrical magnet 6 is fixed to the rotor shaft 4 via a Yanta piece 5, and the rotor 7 is
! has been completed. The side circumferential surface of the magnet 6 is magnetized uniformly in the axial direction and with N&S poles alternating in the circumferential direction, forming rotor-tough magnetic poles.

The stator 8 is constructed by stacking two coil units 11 in which a donut-shaped coil 9, which is wound around the rotor 7, is wrapped in a stator core 10 formed of a thin plate.

This is because the two-stage stacking is a two-phase system. 12 is a coil bobbin, and 13 is a lead wire.

12 and WSi2 are a plan view and a side view showing the magnetic pole plate 15 constituting the stator core 10. FIG. Magnetic pole plate 1
5 is formed by pressing a thin plate, and has a large number of comb-shaped teeth 16 arranged in a cylindrical shape. Two magnetic pole plates 15 are placed opposite each other, and each @16 is connected to the other tooth 1.
6 and the teeth 16 are assembled to form the stator core 10 so as to fit into the groove g17. It forms the magnetic pole of the stator 8.

Between conventional stepper motors with vli of more than
Eight points will be explained.

In order to reduce the step angle of the stepping motor, the number of magnetic poles must be increased, and the number of teeth 16 on the magnetic pole plates 15 that constitute the magnetic poles must be increased. However, the width of @16 formed by press working is limited by the plate thickness, and it is generally difficult to form it to a width less than the plate thickness of the magnetic pole plate 15. Further, it is necessary to ensure a width in which the teeth 16 of the opposing magnetic pole plates 15 fit into the groove portion 17 between the teeth 16 . Therefore, magnetic pole @1
The number of teeth 16 that can be formed on the stator 5 is limited by the inner diameter of the circumference on which the teeth 16 are arranged, that is, the inner diameter of the stator. For this reason, there is a problem in that when the step angle is made small, the outer diameter of the stepping motor becomes large.

In addition, even in the case of Rotoruf's cylindrical magnet 6, when the step angle becomes smaller compared to the diameter, the pitch of magnetization on the side circumference of the magnet 6 becomes finer, and only the vicinity of the surface of the magnet 6 can be magnetized, resulting in the volume utilization efficiency of the magnet. There was also a problem that the torque of the stepping motor decreased due to a decrease in magnetic force.

Due to these factors, for conventional stepping motors, for example, those with an outer diameter of 401 mm, the number of steps per revolution is approximately 96 steps (step angle 3.75 degrees).

However, in recent years, due to demands for lighter weight and simpler structures, direct drive has become common with stepping motors without the use of reduction gears, and smaller step angles and higher torque have become issues even for small-diameter stepping motors. Ta.

[Problem that the invention seeks to solve]

The present invention was made to solve the above problems, and an object of the present invention is to provide a stepping motor that can reduce the step angle and increase the number of steps per rotation without increasing the outer diameter. shall be.

[Means for solving problems]

For this reason, in the first invention, two magnetic pole plates having a large number of teeth protruding from the circumference in the axial direction are combined so as to face each other so that the directions in which the teeth protrude are opposite to each other, and the teeth are A stepping motor is provided with a magnetic pole core serving as a magnetic pole, and the magnetic pole plate has a continuous portion in which a plurality of teeth are arranged at an equal pitch, and a missing portion in which a plurality of teeth at the same pitch are missing. A stepping motor characterized in that it has a first magnetic pole core which has the two magnetic pole plates alternately and is combined with the two magnetic pole plates so that the continuous portions thereof enter into the missing portions of the opposing magnetic pole plates. Ru.

Further, in the second invention, two magnetic pole plates each having a large number of teeth protruding from the circumference in the axial direction are combined to face each other so that the directions in which the teeth protrude are opposite to each other, and the teeth are A stepping motor comprising a magnetic pole core serving as a magnetic pole,
The magnetic pole plate has a large number of teeth arranged at equal pitches over the entire circumference, and the two magnetic pole plates are arranged so that the tips of the teeth face each other in grooves between the teeth of the magnetic pole plates, and , there is provided a stepping motor characterized in that the combined magnetic pole cores of ttS2 are prevented from entering the opposing grooves.

[Effect]

According to the configuration of the wSl invention, since the teeth of the opposing magnetic pole plates fit into the missing parts of each other, there is no need to ensure a width sufficient for the teeth to fit into the grooves between successive teeth, and the grooves The width of the teeth can be made larger compared to the width of the tooth. Therefore, the pitch between the teeth can be made smaller compared to the width of the teeth which is limited by the thickness of the magnetic pole plate, and the step angle can be made smaller.

According to the configuration of the invention @2, the teeth of the opposing magnetic pole plates do not enter into the grooves that face each other, so the width of the teeth can be made larger than the width of the grooves. Therefore, the pitch between the teeth can be made smaller compared to the width of the teeth, and the step angle -t- can be made smaller.

〔Example〕

Embodiments of the present invention will be specifically described with reference to the drawings.

Figure tIS1 is a sectional view showing a two-phase stepping motor according to the present invention, Figure ff12 is a developed view of the stator core,
FIG. 3 is a developed view of the a-tacho 7. In this embodiment, the first invention is applied to the stator core, and the second invention is applied to the rotor core.

A rotor shaft 4 is rotatably supported by a bearing 2.3 fixed to the housing 1. Two magnets 21 and 22 are fixed to the rotor shaft 4 in the shape of a cylindrical plate and magnetized in the direction of the thickness (in the axial direction).

Each magnet 21.22 has two magnetic pole plates 23.24 respectively.
and 25.26. Magnetic pole plate 23-2
6 has the same shape formed by pressing a thin plate made of magnetic material, and has a large number of teeth 27 on the outer periphery, which are formed by punching out the outer periphery and bending them to protrude in the axial direction. There is.

The two magnetic pole plates 23 and 24 that clamp the magnet 21 are assembled facing each other so that the protruding directions of @27 are opposite to each other, and the teeth 27 of the magnetic pole plate 23 are connected to the N pole and the magnetic pole plate. It forms a magnetic pole core with 1li27 of 24 as the S pole,
The two magnetic pole plates 25 and 26 that clamp the magnet 22 are also combined in the same way to form a magnetic pole core with each tooth 27 serving as a magnetic pole. Rotor shaft 4, magnets 21, 22 and 4 pieces! Pole plate 23
~26 constitute the rotor.

Figure 3 shows the four magnetic pole plates 23 to 26 that make up the rotor core.
FIG.

The 'tlJ27 of each magnetic pole @23 to 26 are arranged on the circumference at equal pitches, and the width of the teeth 27 is approximately equal to the width of the groove 28 between the teeth. ! , has been. The magnetic pole plate 23 and the opposing magnetic pole plate 24 are assembled with their phases shifted by 172 pitches, and the tips of the teeth 27 Mmu 281. :
The opposing teeth 27 are assembled so that they do not enter m[128]. The magnetic pole core consisting of the magnetic pole plates 23 and 24 and the magnetic pole core consisting of the magnetic pole plates 25 and 26 are combined in exactly the same phase. The a-evening magnetic pole core forms the second magnetic pole core.

This will be explained with reference to FIG. 1 again. The stator has two donut-shaped fills 31,32.

Each coil 31, 32 housed in the fillobin 12 is
They are held between two magnetic pole plates 33, 34 and 35, 36, respectively. Each of the magnetic pole plates 33 to 36 has the same shape and is formed by pressing a thin plate made of a magnetic material, and is formed by punching out the inner periphery, protruding in the axial direction, and bending it into a large number of shapes. l! 137 on the inner circumference. Two magnetic poles @33 and 34 are combined to face each other so that the protruding directions of the teeth 37 are opposite to each other, and form a magnetic pole core of the coil 31 with each tooth 37 serving as a magnetic pole.

The magnetic pole plates 35 and 36 are similarly assembled and serve as the magnetic pole core of the coil 32. Two sets of coils 31 and 32 wound around the fill bobbin 12 and four magnetic pole plates 33 to 36 constitute a stator.

Figure 2 shows four magnetic pole plates 33 to 3 that make up the stator core.
6 is a developed view of No. 6.

Each magnetic pole plate 33-36 consists of two teeth 37. ! The drawing part gusset part 403 teeth alternately have missing parts 41 where FA has been performed. 113, each of the magnetic pole plates 33 to 36 has a missing part 41 in which three teeth are missing from a large number of teeth arranged at equal intervals on the inner periphery, and a continuous part 40 in which two teeth 37 are left. It has a shape in which these are arranged alternately. The pitch of $37 is equal to the pitch of the teeth 27 of the magnetic pole plates 23 to 26 of the rotor, and the width of 1ll137 is approximately equal to the width of the m portion 38 between the teeth. It is L.

The magnetic pole plates 33 and 34 are assembled with their phases shifted by 572 pitches from each other, and are assembled so that the continuous portion 40 enters into the missing portion 40 of the other. Magnetic pole plate 33
Since the phases of and the magnetic pole plate 34 are shifted by 572 pitches, this is equivalent to a mutual phase shift of 172 pitches.

The @polar plates 33 and 34 are each excited to the N pole or the S pole depending on the direction of the excitation current of the coil 31.

The magnetic pole core of the coil 31 consisting of the magnetic pole plates 33 and 34 and the magnetic pole core of the coil 32 consisting of the magnetic pole plates 35 and 36 are assembled with their phases shifted by 174 pitches to form a stator core. The magnetic pole core of the stator is rjSl
It forms the magnetic pole core of.

The operation based on the above configuration will be explained.

71'14 to 9 are developed views showing the relative positions of the rotor core and the theta core, and are views seen from the rotor side to the stator side.

Four magnetic pole plates forming the rotor core 23.24.25.26
Is the magnet 21.22, each of which is a magnetic pole board, and the magnetic pole board 24.26, which is constantly exciting in the S pole, has a 6 -status core 33.34.35.
36 is excited to the north pole or the south pole depending on the direction of the exciting current of the coils 31 and 32.

First, as shown in FIG. 4, assume that the teeth of the magnetic pole plate 26 of the rotor are in a position where they overlap the teeth of the magnetic pole plate 35 of the stator.

When only the coil 31 is energized in the positive direction at this position, the magnetic pole [33 is excited to the north pole and the magnetic pole plate 34 is excited to the south pole, as shown in the figure. Then, the magnetic pole plate 34 of the stator is excited to the S pole.
The teeth 51, 52 of the magnetic pole plate 23 of the rotor are attracted to the teeth 61, 62 (hereinafter referred to as stator teeth) of the rotor, and the teeth 56, 57 of the magnetic pole plate 24 (hereinafter referred to as U-tor teeth) are repelled. . Both are forces that move the rotor to the left in the drawing. *1 of the stator excited to the N pole! At +03.64, rotor tooth 53.54 is repelled and rotor tooth 59.60
is attracted, generating a force that moves the rotor to the left in the drawing. Almost no force acts on the stator teeth with different polarities and the rotor teeth 58 and 55 located at the gap between the teeth.In this way, torque acts on the rotor in the left direction in the drawing, and the rotor becomes 1/4 Pitch move to the position shown in the tjIS diagram.

At the position shown in Fig. 5, the coil 31 is de-energized and the coil 32
When only the current is applied in the opposite direction, the magnetic pole plate 35 is magnetized to the S pole, and the magnetic pole plate 36 is magnetized to the N pole. Then, the teeth 71.72 of the rotor are attracted to the teeth 81.82 of the stator excited to the S pole, and the $76.77 of the rotor is repelled. NMi
The rotor teeth 73.74 are repelled by the stator's magnetized stator @83.84, and the rotor teeth 79.80 are attracted. Both the above-mentioned attractive force and repulsive force act in a direction to advance the rotor to the left in the drawing, and the rotor moves by 1/4 pitch to the position shown in FIG.

In the position shown in FIG. 6, the coil 32 is de-energized and the filter 3
By energizing only 1 in the opposite direction, the magnetic pole plate 33 is excited to the S pole and the magnetic pole 1234 is excited to the N pole, and the rotor receives torque to the left in the drawing and moves by 1/4 pitch to f! S7 Proceed to the position shown in Figure.

tJS7 In the position shown in the figure, the magnetic pole plate 35 is in the N
At this point, the magnetic pole plate 36 is energized to the S pole, and the rotor receives a torque to the left in the drawing and moves 1/4 pitch to the position shown in FIG.

If the coil 31 continues to be energized in the position shown in FIG. Balance of repulsive force with rotor teeth 71, 72, 73 and stator teeth 83.84 and rotor teeth 79.8
A holding torque is generated by the balance of the repulsive force with 0.86.

Further, the position shown in FIG. 8 is equivalent to the position shown in FIG. 4. In this way, the rotor can be moved by 174 pitches by switching the excitation currents of the coils 31 and 32.

In the above explanation, coil 31.3 is used to simplify the explanation.
2 to sMJ at a time, but the two coils 3
Even if the two-phase excitation method is used in which both 1.32 and 1.32 are energized, the rotor's equilibrium position ff1 (stop position ff1) is only shifted by 178 pitches, as shown in FIG. 9, and the operation is the same.

As explained above? ! ! 17 with a pitch of 127.37
The rotor can be rotated with a step angle of 4. The step angle is 1/4 of the pitch of the teeth of the magnetic pole plate, which is the same as before, but since the pitch of the teeth of the magnetic pole plate can be made smaller than before, the step angle can be made smaller. .

A conventional stepping motor with an outer diameter of 401
The maximum number of rotation steps was 96 steps, but according to this embodiment, a rotation step number of 200 steps has become easily possible.

Furthermore, although it seems that the torque would be reduced because the missing portion 41 is provided on the stator's magnetic pole plate, according to experiments, it was possible to secure more torque than the conventional one. This is because the total number of teeth is not much different from the conventional one due to the small pitch of the teeth, and the magnet efficiency is improved because the rotor magnet only needs to be magnetized uniformly in the axial direction instead of surface magnetization. This is thought to be due to the increase in magnetic flux from the rotor.

When we roughly examine the torque ratio between the conventional 96-step tooth and the 200-step tooth according to this embodiment, we find that the coefficient is 275, which is due to the fact that three of the five teeth are missing due to the missing portion 41. A coefficient of 1 is due to the fact that the width of the teeth is approximately the same as before, and a coefficient of 50/24 is due to an increase in the number of teeth.
Considering the coefficient due to magnet efficiency, the torque ratio becomes 215 X I X 50/24 X (magnet efficiency), and it can be understood that approximately the same torque can be secured.

This embodiment described above has the following advantages.

(1) The number of teeth 37 in the delay part 40 of the stator magnetic pole plate is one less than the number of teeth missing in the missing part 41. Therefore, the two magnetic pole plates 33 constituting the magnetic pole core are ．．
34 can be easily interposed by shifting the center positions of the teeth 37 by 172 pitches relative to each other so that the continuous s4o enters the missing part 41 of the other, which reduces the number of teeth constituting the magnetic pole. There is an advantage α in that the torque can be maintained by reducing the decrease.

(2) The width of the teeth 27.37 of the stator and rotor magnetic pole plates is approximately equal to the width of the m portion 28.38 between the teeth.
Therefore, there is an advantage α that the magnetic flux distribution formed by using the teeth 27, 37 as magnetic poles exhibits relatively smooth changes, and torque fluctuations are relatively small.

Also, if the width of the teeth 27.37 is too narrow, the magnetic flux will decrease,
Torque decreases. Conversely, the width of the tooth 27.37 is the width of the groove 28.37.
If the width is too large compared to the width of 38, the spatial distribution of magnetic flux in the gap becomes unbalanced, and the torque decreases on the contrary. Therefore, it has the advantage of being able to secure torque. (3) A magnetic pole core is also used for the rotor. That is, a magnet 21 magnetized in the axial direction is held between two magnetic pole plates 23 and 24 having comb-shaped teeth 27, with the teeth 27 serving as magnetic poles.

For this reason, the rotor magnets do not need to be magnetized at narrow pitches on the side circumferential surface, but only need to be magnetized uniformly in the axial direction (thickness direction), increasing the efficiency of magnet use and It has the advantage of increasing the torque by strengthening the magnetic flux from the magnetic poles.

In the embodiment described above, the number of teeth in the chain a section 40 of the magnetic pole plates 33 and 34 of the stator was two, and the number of teeth missing in the missing portion 41 was three, but for example, 2! ! 4 continuations, 5 missing parts
Of course, any number of books may be used, such as books.

Further, the magnetic pole core used in the stator and the magnetic pole core used in the rotor can be exchanged with each other.

That is, the same effect can be obtained by using a first magnetic pole core having a continuous portion and a missing portion in the rotor, and using a jQ2 magnetic pole core in which teeth are arranged at an equal pitch in the stator.

Furthermore, it is possible to reduce the step angle by using the first or tIS2 magnetic pole core only in the stator and by surface magnetizing the side circumference of the cylindrical magnet without using a magnetic pole core in the rotor.

However, with a small step angle, the efficiency of magnet use is low and the torque is reduced, which is disadvantageous.

〔Effect of the invention〕

As explained above, the present invention has the above configuration and can reduce the pitch between the teeth compared to the width of the teeth which is limited by the thickness of the magnetic pole plate. This has the excellent effect of being able to reduce the step angle without significantly reducing the diameter. Furthermore, as a ripple effect, since the outer diameter of the rotor is made smaller than the step angle, the moment of inertia of the rotor can be reduced, and the self-inductance of the stator coil can also be reduced. This has the effect of increasing the responsiveness of the stepping motor and enabling high-speed operation.

[Brief explanation of drawings]

1 to 9 show an embodiment of the present invention, FIG. 1 is a sectional view of a stepping motor according to the present invention, Pt52 is a developed view of a stator core, and FIG. 3 is an IJL of a rotor core.
The leap diagram and FIGS. 4 to 9 are developed views of the stator core and rotor core to explain the operation, and tIS 10 to 1
3 shows a conventional chipping motor, FIG. 10 is a sectional view, FIG. 11 is an exploded perspective view of the main parts, FIG. 912 is a plan view of a magnetic pole plate forming a stator core, and FIG. 13 is a side view. 4... Rotor shaft, 6... Magnet, 9... Coil, 1
5... Magnetic pole plate, 16... Teeth, 17... Groove, 21
．． 22...Magnet, 23.24.25.26...Rotor magnetic pole plate, 27...Teeth, 28...m part, 31.3
2... Coil, 33.34.35.36... Stator magnetic pole plate, 37... Teeth, 38... Groove, 40...
・Continuous part, 41... Missing part. Agent Patent Attorney Isamu Goto Figure 10 Figure 11

Claims (1)

[Claims] 1. Having a large number of teeth protruding from the circumference in the axial direction. 2.
A stepping motor is provided with a magnetic pole core in which two magnetic pole plates are combined to face each other so that the protruding directions of the teeth are opposite to each other, and the teeth serve as magnetic poles. The two magnetic pole plates have continuous parts arranged at a pitch and missing parts in which a plurality of teeth of the same pitch are missing, and the two magnetic pole plates are arranged in the same manner as the continuous parts of the magnetic pole plates that face each other. A stepping motor characterized by comprising first magnetic pole cores that are combined so as to fit into the missing portion. 2. The stepping motor according to claim 1, wherein the number of teeth in each continuous position of the magnetic pole plate is one less than the number of teeth missing in each of the missing portions. 3. The stepping motor according to claim 1, wherein the width of the teeth of the magnetic pole plate is approximately equal to the width of the structure between the teeth of the continuous portion. 4. The stepping motor according to claim 1, wherein the first magnetic pole core is used as a magnetic pole core of a stator and includes a coil sandwiched between the two magnetic pole plates. 5. Claim 1, wherein the first magnetic pole core is used as a magnetic pole core of a rotor, and includes an axially magnetized magnet that is clamped between the two magnetic pole plates.
Stepping motor described in section. 6 2 with multiple teeth protruding from the circumference in the axial direction
A stepping motor is provided with a magnetic pole core in which two magnetic pole plates are assembled facing each other so that the protruding directions of the teeth are opposite to each other, and the teeth serve as magnetic poles, the magnetic pole plate having a large number of teeth. The two magnetic pole plates arranged at equal pitches over the entire circumference are arranged so that the tips of the teeth face the grooves between the teeth of the opposing magnetic pole plates, and the teeth do not enter the grooves facing each other. A stepping motor comprising a second magnetic pole core combined with a second magnetic pole core. 7. The stepping motor according to claim 6, wherein the width of the teeth of the magnetic pole plate is approximately equal to the width of the groove. 8. The stepping motor according to claim 6, wherein the second magnetic pole core is used as a magnetic pole core of a stator and includes a coil sandwiched between the two magnetic pole plates. 9. Claim 6, wherein the second magnetic pole core is used as a magnetic pole core of a rotor, and includes an axially magnetized magnet held between the two magnetic pole plates.
Stepping motor described in section.