JPS614454A - Multipolar dc motor - Google Patents

Abstract

PURPOSE:To reduce the rotating irregularity to the minimum limit as required without decreasing the efficiency of a motor by extending split surfaces of split poles of a core, and varying the shape and size of the extension. CONSTITUTION:A multipolar (6-pole) inner rotor type DC motor has a field 1 having a permanent magnet ring magnetized at 6 poles, a coil 3 wound around a shaft 2, and cores 4, 5 for enclosing the coil 3. The cores 4, 5 are radially branched toward the field 1, the branched ends are further split to be bent perpendicularly along the outer periphery of the coil 3, and poles 4a, 4b are extended from the core 4, and the poles 5a, 5b are extended from the core 5. Thus, one poles 4a, 5a are extended toward the other poles 4b, 5b, and an armature is stopped at a stable naturally stopping position, and a starting dead point is always avoided to reduce the rotary torque of the armature to the minimum limit as required slightly larger than the load torque at the starting time.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a multi-polar DC motor, and more particularly to a multi-polar DC motor in which a permanent magnet is used as a field and an armature winding is wound concentrically around an axis. The present invention relates to a multi-pole DC motor that can easily improve unevenness and improve efficiency.

The inventor of the present invention has developed a permanent magnet ring that is magnetized with 2n poles (n is a natural number of 2 or more) in which adjacent poles on the circumferential surface are different from each other, and a coil that is wound concentrically around the axis. Wrap cores along the magnetic path from both sides of the flat side of the coil, and intertwine each core alternately on the circumferential surface facing the magnetized surface of the ring of the coil, so that adjacent poles on the circumferential surface of the coil are mutually intertwined. In order to avoid the startup dead center of a multi-pole DC morph that is composed of an armature in which 2n magnetic poles with different polarities are formed and a switching means that switches the current direction of the coil in accordance with the rotation, The shape of the surface of the core facing the permanent magnet ring is formed to be magnetically asymmetrical with respect to the center of the magnetized pole of the ring, so that when energized it is at a natural stop position due to the attractive force of the permanent magnet ring of the armature when energized. The center of the magnetic pole of the armature is located at a position shifted from the relative rotational direction of the armature, and the armature winding is wound concentrically with respect to the shaft center, making winding easy and increasing the number of windings. He has filed an application for a multi-polar DC motor that can increase motor efficiency and facilitate flattening of the motor (Japanese Patent Application No. 56-159710).

As a specific embodiment for avoiding the starting dead center, the shape of the surface of the core that faces the permanent magnet ring, which forms the magnetic path of the concentrically wound coil, extends in the direction of relative rotation of the armature. disclosed.

However, in a DC motor with a concentric armature winding, the core shape of the armature is magnetically asymmetrical to avoid starting dead center, so it is inevitable that some degree of uneven rotation will occur. do not have.

In other words, in a DC motor with a permanent magnet ring as the field and a concentric armature winding as described above, in order to increase efficiency, the switching point of the current to the armature is aligned between the center of the armature's magnetic pole and the field. On the other hand, since the armature winding is concentrically wound, if the armature stops at a point where the magnetic pole center of the armature and the magnetic pole center of the field coincide, Unable to start.

This means that even if the core shape of the armature is magnetically asymmetric, the armature becomes de-energized at a position where the magnetic pole centers of the armature and the field coincide, and the permanent magnet If the attraction torque with the armature is smaller than the load torque, the armature will continue to stop at the same position and will not start.

Therefore, in order for the DC motor with the above configuration to start without fail to avoid starting dead center, when the armature becomes de-energized at the position where the magnetic pole centers of the armature and the field coincide, the permanent magnet It is necessary that the attraction torque of the permanent magnet ring exceeds the load torque, thereby avoiding the starting dead center, but the above-mentioned uneven rotation occurs because the attraction torque of the permanent magnet ring is large when the armature is not energized. will occur.

The inventor of the present invention established the following conditions for minimizing rotational unevenness: The load torque must be slightly higher than the actual load torque.

(b) At the position of (a), the suction torque is the maximum torque.

I found 7.

However, the condition (b) cannot be satisfied by simply extending the shape of the field-facing surface of the armature core, as in the embodiment of the application. That is, even if the extension length and extension width of the extension portion of the core are changed, the maximum torque position of the suction torque hardly changes, and the maximum torque position cannot be set to an arbitrary position.

On the other hand, in order to increase the efficiency of the DC motor as mentioned above, the magnetic flux of the field must not only pass through the core that wraps the armature coil from both flat sides, but also pass through the N-3 poles adjacent to the field poles. It is preferable to pass through the opposing part of the permanent magnet ring of the core located in between.

To this end, it is sufficient to minimize the gap between adjacent cores, which are intricately arranged and alternately of different polarities on the circumferential surface of the concentrically wound armature winding. If the gap is made smaller by extending the field-facing surface of the core, the attraction torque of the permanent magnet becomes too large and a large starting current is required.

Therefore, the inventor of the present invention proposed that the magnetic pole formed on the field-facing peripheral surface of the concentrically wound armature winding be composed of a main pole and a commutating pole, and changing the position and shape of the commutating pole. We have developed a multi-pole DC motor that satisfies the conditions (a) and (b) above, has minimal rotational unevenness, and can improve motor efficiency (Japanese Patent Application No. 59-085).
No. 038).

However, 1. If the magnetic poles of the armature are simply formed from the main pole and the commutative pole, when the position and shape of the commutative pole are changed to satisfy the conditions (a) and (b) above, slight changes may occur. A problem arose in that the characteristics changed significantly and it was difficult to adjust them.

The present invention has been made in view of the above problems, and its purpose is to solve the above (a) and (b) with respect to changes in the position, shape, and size of the core that forms the magnetic poles of the armature. Our goal is to provide a multi-pole DC motor that has a small rate of change in characteristics that satisfies the conditions of 2n poles (n is 2
above natural numbers) A magnetized permanent magnet ring and a coil wound concentrically around the axis are wrapped with cores along the magnetic path from both sides of the flat side of the coil, and each core is wrapped around the ring of the coil. An armature in which magnetic poles of 2n poles are formed alternately on the circumferential surface facing the magnetized surface so that adjacent poles on the circumferential surface of the coil are different from each other, and the current direction of the coil is rotated. In a multi-pole DC motor comprising a switching means that switches in response to ? to the ring magnetized surface of the core?
The magnetic poles are divided into two in the circumferential direction on the facing surface of the armature, and the attraction torque by the permanent magnet ring when not energized at a position where the magnetic pole center of the armature when energized and the magnetic pole center of the permanent magnet ring coincide is the load torque at startup. An extending portion having a size and shape slightly larger than the above is formed by extending from one or both of the dividing surfaces of the two divided magnetic poles toward the other divided pole.

Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

In FIG. 1, which is a plan view of a six-pole, inner-rotor DC motor, reference numeral 1 denotes a field consisting of a permanent magnet ring magnetized to six poles.

2 is a shaft, and a coil 3 is placed around this shaft 2.
is wound.

4 is a core that wraps around the coil 3 from one of the flat side surfaces of the coil 3, and 5 is a core that wraps around the coil 3 from the other flat side of the coil 3, each of which is fixed to the shaft 2.

These cores 4 and 5 branch radially toward the field 1, and the cores 6 also branch as shown in Figure 2, which is a developed outer peripheral surface. The tip is further divided into two parts and bent at right angles along the outer peripheral surface of the coil 3, and the pole 4a and the pole 4 are separated from the core 4.
A pole 5a and a pole 5b extend from the core 5, respectively.

The poles 4a, 5a extend toward the poles 4b, 5b, and the center of the magnetic pole formed by the poles 4a, 4b and the poles 5a, 5b is oo in FIG.

The positions are 60° and 120° (180°, 240°, and 300' are not shown). Note that FIG. 1 shows a state in which the armature is at a natural stop position under no load.

In this way, the magnetic poles of the armature are changed to poles 4a, 4b and 5a.
, 5b and one pole 4a.

By extending 5a to the other poles 4b and 5b with the same numbers, the rotational torque (attractive torque between the field and the armature) when the armature is not energized and under no load is equal to the magnetic poles of the magnet. As shown in Figure 3, where the center is aligned with the magnetic pole center of the armature when energized, the rotational torque when the armature rotates to the right due to suction 1-rook is assumed to be 10, and the If the rotational torque when rotating the armature to the left is -, then the armature rotates to the right with a rotational torque of 10 and stops at a stable natural stop position P1 under no load. Further, when negative rotational torque is applied to the armature, the armature reaches an unstable stop position P2, and when this stop position P2 is exceeded, the armature rotates clockwise toward the natural stop position P1 at the front of rotation. Become.

And pole 4. By forming the extensions from the poles 4b and 5b and the shape and size of the extensions of the poles a and 5a, the armature and the field 1 can be positioned at their respective magnetic pole centers to the armature current switching position. It is easy to maximize the rotational torque at a certain time, and it is also possible to easily set the maximum rotational torque to be slightly larger than the required load torque at startup.

Therefore, the armature does not stop at the armature current switching position even under load (therefore, starting dead center is always avoided, and the armature rotational torque must be slightly larger than the load torque at startup). - Since it can be easily changed to the minimum required level, irregular rotation of the armature can be minimized.

Note that the armature uses switching means (not shown) to change the current direction of the coil 3 at a position where the magnetic pole center of the armature and the magnetic pole center of the field 1 coincide.
In terms of efficiency, it is preferable that the direction of rotation is such that the center of the magnetic pole when energized to the armature at the natural stop position is directed toward the midpoint M of the magnetic poles of the field 1.
In Fig. 1, the rotation is clockwise. Furthermore, the configuration is the same for any of the field rotation type, outer rotor type, and inner rotor type.

Next, a specific example of a DC motor in which the armature magnetic poles are divided into two parts and an extension portion is formed in one pole will be described.

First, in Fig. 4, which shows a DC motor that is easy to assemble and has excellent practicality, 11 is a permanent magnet ring which is a stator, and N is a permanent magnet ring.

Six poles are magnetized on the inner peripheral surface so that the S poles are alternate. Note that by setting the number of magnetic poles to 2 (2m+1) poles (m is a natural number of 1 or more), opposing magnetic poles are always different.

A coil 12 is formed by winding an electric wire 12b inside a circular hobbin 12a having a shaft insertion hole in the center.

Reference numeral 13 denotes a lower core, which includes a disk portion 13a disposed concentrically on the lower surface of the coil 12, and a portion 120 from the periphery of the disk portion 13a.
The poles 13b and 13C are branched and extended into three poles at a declination angle of degrees, and their tips are further divided into two, and the poles 13b and 13C are bent at right angles along the outer peripheral surface of the coil 12.
The extension part 13d extends toward C, and is formed by pressing an iron plate.

14 is an upper core arranged concentrically on the upper surface of the coil 12, and like the lower core 13, it has a disk portion 14a.

It consists of a pole 14b, a pole 14c, and an extension part 14d.

The lower core 13 and the upper core 14 are arranged on both sides of the coil 12, with the pole 13b and the pole 13c positioned between the poles 14b and 14c, thereby forming six magnetic poles. .

15 is a commutator, which is a disc 15a made of an insulating material and having a shaft insertion hole in the center.
and six commutator pieces 15b attached radially from the center on one side of the disc 15a. Every other commutator segment 15b is electrically connected to form two commutator groups, and the coil 12 is connected to each commutator group.

Reference numeral 16 denotes a shaft, which has a flange 16a formed approximately at the center in the length direction, and a stepped portion 16b and a stepped portion 16C at the lower end.
is formed, and an engagement portion for the transmission mechanism is formed on the upper end side circumferential surface.

The above-mentioned commutator 15 and upper core 14 are connected to this shaft 16.
, the coil 12 and the lower core 13 are inserted, and the lower core 13 is caulked and fixed at the stepped portion 16b.

Reference numeral 17 denotes a brush, and a rectangular plate made of phosphor bronze is formed with an arc-shaped notch 17a serving as a relief part for the flange 16a at the center of one long side, and a brush 17a is formed at both corners located on this long side as will be described later. A hole 17b that engages with the case is bored,
A hole 17c to which a lead wire 18 for power supply is connected is formed at both corners located on the other long side, and a sliding contact portion 17d for connecting to the commutator 15 is cut and raised in the center of the surface. . Note that two sliding contact portions 17d are formed to ensure contact with the commutator 15.

The two brushes 17 are arranged at point-symmetrical positions across the circular surface of the shaft 16, and each sliding contact portion 17d contacts the commutator group of the commutator 15, respectively.

Reference numeral 19 denotes a case molded from a plastic material, and a recess 19 into which the permanent magnet ring 11 is inserted is provided on the upper surface of the case.
a is formed, and the shaft 1 is located at the center of the bottom surface of this recess 19a.
A bearing hole 19b is bored in which the bearing 6 is supported at its stepped portion 16C. Furthermore, four engaging protrusions 19C are drilled into the upper surface, which is the surface where the recess 19a is formed, at positions corresponding to the holes 17b of the brush 17, and lead wires 18 are formed at each corner of the upper surface at positions corresponding to the holes 17c of the brush 17. A hole 19d for inserting and holding is bored.

Reference numeral 20 denotes a plastic plate cover attached to the upper surface of the case 19, in which an engagement hole 20a is bored at a position corresponding to the engagement protrusion 19C, and each corner is provided with the lead wire 18.
A notch is provided to facilitate connection to the brush 17.

Further, a bearing hole 20b for inserting and supporting the shaft 16 is bored in the center of the surface.

Each of the above-mentioned components is, as shown by the dashed line in the figure,
A permanent magnet ring 11 is disposed within the recess 1'9a, and a coil 12. Lower core 13. Upper core 14. Commutator 15. The armature consisting of the shaft 16 is connected to the stepped portion 1 of the shaft 16.
6C is inserted into the bearing hole 19b and arranged in the center of the permanent magnet ring 11, and the solid brush 17 is positioned by inserting its hole 17b into the engagement protrusion 19C, and the cover 20 is inserted into the engagement hole 20a. The shaft 16 is inserted into the bearing hole 20b and engaged with the case 19, the engaging projection 19C is fixed to the cover 20 by heat welding, etc., and the lead wire 18 is passed through the hole 19d to connect the brush. 17 holes 17
Assembly is performed by inserting into C and soldering.

? This type of DC motor has an armature coil that is concentrically wound around the shaft, making it easy to wind the motor, and together with the fact that the commutator and brushes are plate-shaped, it can be made flat and compact. Since the brush is sandwiched between the case and cover and fixed in position, assembly is extremely easy, and the number of poles can be reduced to 2 (2m+1).
Since the brushes are made of poles, the opposing brushes can be placed in point-symmetrical positions with respect to the rotation axis.Furthermore, since the motor is a flat multi-pole type, the rotation transmission mechanism of the motor is free from inefficient worms and worm gears. Instead of using a spur gear with a small reduction ratio, it is possible to use a spur gear with a small reduction ratio.

Next, a DC motor used for driving a floppy disk is shown in FIGS. 5 to 9.

An armature 30 is composed of a coil 32 concentrically wound around a bobbin 31, and a core 33 surrounding the coil 32 so that 20 magnetic poles are alternately different on the circumferential surface facing the rotor.

The core 33 is formed with a pole 33a and a pole 33b, and the pole 33b' has an extending portion 33c extending toward the pole 33a. In addition, the core 33 is
The upper core and the lower core are combined to form a closed magnetic path on the inner circumferential surface of the coil 31, and both the upper and lower cores are press-processed by integrally forming the poles 33a and 33b and the closed magnetic path portion 33d. Therefore, its production is easy.

A fixing member 34 is fitted onto the inner circumferential surface of the armature 30, and its flange portion 34a is fixed to the base plate 35, so that the armature 30 is fixed to the base plate 35.

Reference numeral 36 denotes a rotor, which includes a permanent magnet ring 37 arranged opposite to the outer circumferential surface of the armature 30 and magnetized so as to have different polarities alternately; It consists of a cup-shaped yoke 38 attached to a permanent magnet ring 37, and a shaft 40 fixed to the center of the flat side of the yoke 38 with a nut 39. shirt l
-40 is inserted into a bearing 41 fitted to the inner circumferential surface of the fixed member 34, and the rotor is rotatable.

Note that the yoke 38 may be made of a magnetic material at least at a portion that comes into contact with the circumferential surface of the permanent magnet ring 37.

Reference numeral 42 denotes a Hall element, and one Hall element is provided on a printed circuit board 43 attached to the circuit board 35, facing the permanent magnet ring 37, in order to switch the current direction of the coil 32 by the rotation of the magnetic poles of the permanent magnet ring 37. only.

As the rotor 36 rotates, the Hall element 42 switches the current direction of the coil 32, and different poles are generated alternately at each tip of the core 33, so that the rotor 36 continues to rotate. As a result, the turntable 44, which is fixed to the shaft 40 and into which a floppy disk (not shown) is fitted, rotates.

Next, the rotational speed detection mechanism of the rotor 36 will be explained.

As shown in FIG. 6, the yoke 38 has a peripheral edge that extends outward and is bent at a right angle.
A bent portion 38a is formed having a surface parallel to the curved surface.

Reference numeral 45 denotes a flat permanent magnet ring serving as a power generating magnet, which is attached to the bent portion 38a, and has 6 holes on its flat side to make the magnetic poles smaller in pitch than the magnetic pole pinch of the rotor 36.
The zero pole is alternately magnetized to N and S.

Reference numeral 46 denotes a power generation coil, which is printed and wired on the printed circuit board 43 so as to be close to and face the magnetized surface of the permanent magnet ring 45 . The pinch of the generator coil 46 is the same as the magnetic pole pitch of the permanent magnet ring 45.

Further, in FIGS. 7 and 8, the permanent magnet ring 37 used in the rotor 36 as a power generation magnet is also used as the rotational speed detection mechanism of the rotor 36.

That is, the permanent magnet ring 37 is magnetized toward the axis, and the outer peripheral surface is also magnetized with the same number of magnetic poles that are different from the poles on the inner peripheral surface.

As shown in FIG. 9, the yoke 38 is connected to the permanent magnet ring 3.
It is branched so as to leave a portion of the outer peripheral surface of the permanent magnet ring 37 that faces the magnetic pole, and at the tip of this branch portion 38b, there is a V-shaped branch portion that extends in a V-shape along the peripheral surface of the permanent magnet ring 37. 3
8c is formed, and the tips of the V-shaped branch portions 38C of the adjacent branch portions 38b are close to each other. Therefore, the same number of N and S poles as the magnetic poles of the permanent magnet ring 37 are formed on the outer periphery of the permanent magnet ring 37, facing the printed circuit board 43, with pinches smaller than the magnetic pole pinch of the permanent magnet ring 37. A power generating magnet having magnetic poles with a smaller pitch than the magnetic pole pinch of the magnet ring 37 is formed.

In this case, since the number of magnetic poles of the power generation magnet and the number of magnetic poles of the permanent magnet ring 37 are the same, the Hall element 42 is switched by the power generation magnet.

On the other hand, the generator coils 46 are printed and wired on the printed circuit board 43 so that there are 2m+1 (m is a natural number of 1 or more) between the magnetic poles of the permanent magnet ring 47, and there are three in the illustrated case.

However, due to the rotation of the power generation magnet, the power generation coil 4
The voltage induced in 6 is proportional to the rotational speed of the rotor 36, and the frequency proportional to the rotation of the rotor 36 is -
The rotational speed of the rotor 36 is higher than the rotational speed of the armature 36, and since the magnetic pole pitch of the power generation magnet is smaller than the magnetic pole pitch of the rotor 36, the rotational speed of the rotor 36 between the magnetic poles of the armature 30 is also detected.

The voltage or frequency induced in the generator coil 46 is input to a control circuit (not shown), and this control circuit controls the voltage supplied to the coil 32, etc., and the rotation of the rotor 36 is controlled to a desired speed. becomes.

Note that the power generation magnet and the power generation coil are not limited to those in the above-mentioned embodiments, as long as the detection voltage is appropriate and the rotational speed of the rotor between the magnetic poles of the armature can be detected. Therefore, for example, when the power generation coil 46 is arranged over the entire circumference, the power generation magnet does not need to be installed over the entire circumference, and conversely, when the power generation magnet is installed over the entire circumference, The generating coil may be partial. Further, instead of forming the tips of the branch portions 38b of the yoke 38 in a V-shape, the tips of adjacent branch portions 38b may be bent so as to approach each other.

Furthermore, the number of poles of the armature and rotor is not limited to the above-mentioned embodiment, but for a floppy disk drive, it is 6 to 4.
The 0 pole position is appropriate.

In this DC morph, the armature coil is concentrically wound, making the winding work easier, increasing the number of windings, and achieving superior power consumption efficiency. The number of poles can be easily changed by changing the number of branches in the core surrounding the armature, and since it is a single-phase drive, only one Hall element and its drive circuit are needed to switch the current in the armature coil. Furthermore, the permanent magnet ring of the rotor can also be used as a power generation magnet for detecting the rotor speed, thereby reducing product costs.

In this way, according to the present invention, by extending the dividing surface of the two-divided pole and changing the shape and size of this extending part, the attraction torque between the armature and the field of the permanent magnet ring is reduced. It is extremely easy to make the maximum value slightly larger than the required load torque, and it is also easy to set the maximum torque generation position to the point where the magnetic pole centers of the armature and the field coincide, thereby improving motor efficiency. This has the remarkable effect of reducing rotational unevenness to the minimum necessary level without reducing the speed.

Although the present invention has been variously explained above with reference to preferred embodiments, the present invention is not limited to these embodiments, and it goes without saying that many modifications can be made without departing from the spirit of the invention. It is.

[Brief explanation of the drawing]

Fig. 1 is a plan view of the DC motor according to the present invention, Fig. 2 is a developed view of the outer peripheral surface of the armature, Fig. 3 is a rotational torque curve diagram when no load is applied, and Fig. 4 is an exploded perspective view of the DC motor. 5 to 9 show a DC motor for a floppy disk, FIG. 5 is a plan view, FIG. 6 is a sectional view taken along line AA in FIG. 5, and FIG. 7 is a plan view showing another embodiment. 8 is a sectional view taken along line BB in FIG. 7, and FIG. 9 is a developed view of the rotor outer peripheral surface in FIG. 8. 1... Field, 2... Shaft, 3... Coil, 4, 5... Core, 4a, 5a.
...pole, 4b, 5b...pole, 1
1... Permanent magnet ring, 12... Coil,
12a...Bobbin, 12b...Electric wire, 13
...lower core, 13a...disc part, 13
b, 13c...pole, 13d...extension part, 1
4...lower core, 14a...-disc part, 1
4b, 14c... pole, 14d... extension part,
15... Commutator, 15a... Disc,
15b... Commutator piece, 16... Shaft,
16a...flange, 16b, 16'c,・
・Step part. 17... Brush, 17a... Notch. 17b, 11cm-one hole, 17d... sliding contact part. 18...Lead wire, 19...Case. 19a... recess, 19b... bearing hole. 19C...engaging protrusion, 19d...hole. 20...Cover, 20a...Engagement hole. 20b... Bearing hole, 30... Armature. 31...Bobbin, 32...Coil, 33...
Core, 33a...pole, 33b...pole,
33C...extension part, 33d...closed magnetic circuit part,
34...Fixing member, 34a...Flange part,
35...Substrate, 36...Loaf, 37.
...Permanent magnet ring, 38...Yoke, 38a
・・・Bending part, 38b... Branching part, 38C・
...V-shaped branch, 39... - Nando, 40... Shaft 41- - Hair ring, 42... Hall element, 43...
Printed circuit board, 44... turntable. 45...Permanent magnet ring, 46...Generating coil.

Claims (1)

[Claims] 1. A permanent magnet ring magnetized with 2n poles (n is a natural number of 2 or more) such that adjacent poles on the circumferential surface are different from each other;
A coil wound concentrically around the axis is wrapped with cores along the magnetic path from both sides of the flat side of the coil, and each core is interlaced alternately on the circumferential surface facing the magnetized surface of the ring of the coil. A multi-pole direct current comprising an armature in which 2n magnetic poles are formed such that adjacent poles on the circumferential surface of the coil are different from each other, and a switching means for switching the current direction of the coil in accordance with rotation. In the motor, each pole is divided into two in the circumferential direction on the surface of the core facing the ring magnetized surface, and the magnetic pole center of the armature when energized matches the magnetic pole center of the permanent magnet ring when not energized. The size is such that the attraction torque by the permanent magnet ring slightly exceeds the load torque at startup,
A multi-pole DC motor in which a shaped extending portion extends from one or both dividing surfaces of two divided magnetic poles toward the other divided pole.