JPS62181651A - Small-sized dc motor and its winding method - Google Patents

Abstract

PURPOSE:To reduce the high frequency noise and to obtain a high output by dividing commutator segments of a motor with multipolar odd-numbered slots into the doubled number of the slots, short-circuiting the facing commutator segments each other and performing the wave-winding and connection of a coil for every other commutator segment. CONSTITUTION:A rotor made up of an iron core 22 is rotatably provided against a stator to which four (4) permanent magnets 21 are provided. A commutator 24 is fixed to the rotor. Seven (7) slots S are provided to the iron core 22 and seven (7) coils L wound around every other slot S are wave-wound and connected through a commutator 23 into which the commutator segment is divided to double the slots. At this moment, every other commutator segments are wave-wound and connected, while the commutator segments situated in the symmetrical positions are short-circuited each other. Thus, the coil short- circuited by a brush 24 provided to the stator is always one single coil. In changing over this short-circuited coil, it can easily be conformed to the neutral point, so that the high frequency noise can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a small multi-pole DC motor having a plurality of permanent magnets as a stator, and a winding method thereof.

(Prior Art) Small DC motors used as actuators for industrial robots and other automatic control devices are required to have high efficiency and high output in terms of walking capacity.

Additionally, motors used for such purposes may be directly controlled by microcomputers or
Since it is controlled by a control device using a microcomputer, it is necessary to minimize the generation of radioactive i''6-frequency noise that could cause the microcomputer and its peripheral equipment to malfunction.

Small DC motors increase the number of poles of the stator's permanent magnetic field,
Moreover, it is well known that the output can be increased by increasing the number of slots in the rotor and increasing the number of coils according to the number of slots. There is a winding method for multiple poles.

In the type-wound connection, the number and position of the brushes and the windings are arranged in accordance with the arrangement of the magnetic poles of the stator, so it is relatively easy to align the brushes.

On the other hand, a wave winding connection with 4 or more poles has the same output as a type winding connection,
Since a smaller number of turns is sufficient to obtain the same characteristics, it is advantageous for increasing output.

That is, the basic formula for motor design is as follows.

1゛ φg= (60E/N1)X (a/P)X 1
08 (axwel14ern)゛r; twice the effective effective number field number line) Ternφg: Total magnetic flux per magnet pole MaxwellE: Applied voltage
VoltsNl: Initial rotation speed
r, ρ1ma: Number of parallel circuits P: Number of magnetic poles of magnet However, the initial rotation speed (N1) is set so that the no-load loss is 0.
This is the number of revolutions when it is assumed that this does not exist, but it is used because it is easy to understand.

Now, in order to check the output depending on the total number of windings and the number of poles, with the initial rotation speed (Ni) and applied voltage (E) constant, A=(60・E/N1)XIO' (Maxwel
14ern).

If the total number of windings is Ta, then T=2Ta.

From the basic formula Ta・φg=0.5X(a/P)XA becomes.

As is well known, in the wave winding connection, when the coil at the beginning of winding is connected, it goes around the core slot in the commutator piece and the end of the last coil winding becomes a closed circuit, so when two brushes are used, a closed circuit is formed. The number a -2.

When P=n pole Type winding number Tar Wave winding number Ta Ta・φg=0.5X(a/P)XA Smell it.

(1) Type winding connection a=n a/n=1,',T
ar・φg=0.5XA (II) Wave winding connection a/n = 2/n,', T
aw・φH=0.5X(2/n)XA To give a concrete example, (i) Double-pole double winding connection a=2 n=2,', Ta
r・φg=o, 5XA (ji) 4-pole heavy winding connection a=4 n=4,',
Tar・φ[=0.5XA (iii) 4-pole reduced winding connection a = 2 n =
4,', T a v ・φ, = 0.25XA i)
Comparing the 4-pole heavy winding connection in (iii) and the 4-pole reduced winding connection in (iii), Tar1φ1z=2TaPφt, and if the total magnetic flux φg per magnet pole is constant, Tar=
2 Taw.

As described above, in the case of the 4-pole reduced winding connection, it can be seen that when the same 4-pole heavy winding rotor is used, the same output can be obtained with 172 turns of the pattern winding connection.

(Problem to be Solved) However, in the case of multipole, the wave winding connection is, in principle, connected to odd numbered slots, but it has the following drawbacks.

(2) When using multiple poles, the number of coils that are short-circuited simultaneously by the brush increases, similar to the parallel winding connection of even slots, and the number of coils that are substantially involved in torque generation decreases.

■Multiple coils that are shown at the same time have different angles with respect to the neutral point, and when one coil is aligned with the neutral point, the other coil deviates greatly from the neutral point,
The generation of sparks increases and generates radioactive high frequency noise.

The above point (■) is a particular problem with respect to start-up when used in a servo system, and (■) is related to the basic problem of use, which is that it promotes the generation of electrical noise and shortens the life of the brush. However, 1 and N are both preferable.

Conventional examples for the above case (2) are shown in FIGS. 4 and 5, and FIG. 5 also includes the case (2).

Figure 4 is an example of a 2-pole 8-slot double-wound connection, with a brush (
When the electrodes (+) and (-) of A) are in the positions shown in figure (a), coil "8" and coil "4" are connected as shown in figure (b).
By shorting the two coils, six coils are involved in torque generation.

In addition, in the following explanation and illustrations, the coil number is referred to as r.
lJ, r2J, ..., commutator strip numbers (1), (2)
, . . . (However, 0 is not added in the drawing), and the ball numbers between each slot are expressed as [11, [2], . . .

In the case of this figure 4, each time each commutator piece is switched, the electrodes (+) and (-) of the brush (A) are driven repeatedly by 6 coils and 8 coils, resulting in a large torque ripple. But two coils are shorted, for example coil r8Jr4J
Since they are parallel and symmetrical, it is easy to align the neutral points of the coils, which reduces the generation of back electromotive force and prevents the generation of high frequency noise.

Figure 5 is an example of a 4-pole 7-slot wave winding connection, with the brush (A)
When the electrode (-) is in the position shown in Figure (a).

As shown in Figure (b), coils "1" and "5" are short-circuited at the same time, the brush (A) advances a little, and when the (-) pole is on the commutator piece (2), the (+) pole Accordingly, coil "3"
and "7" are short-circuited at the same time, and these are sequentially advanced in the numerical order of the commutator segments.

In this case, the width of the brush (A) is 172 mm of the central angle of the commutator piece.
When ideal surface contact is made, it always operates with a 5-coil drive of a 2-coil shot.

If these two coils are always short-circuited, there will be little torque ripple, but there will always be two coils that are not involved in torque generation, resulting in poor efficiency.Moreover, the two coils that are short-circuited at the same time are not parallel. , form a predetermined angle depending on the number of slots, so when the neutral point is aligned with one coil, the other coil deviates from the neutral point, generating a high back electromotive voltage and generating high frequency noise.

Further, since the contact between the brush and the commutator piece is not an ideal surface contact, there is a period in which the coil is not substantially shorted, and 7-coil drive and 5-coil drive occur alternately, resulting in large torque ripples.

Figure 6 shows an example of a 2-pole 7-slot double-wound connection, where the short coil is always driven by one 6, and even if the contact surface of the brush (A) is in line contact in the worst case, the 6-coil and 7-coil alternate operation. Therefore, only one coil's worth of torque ripple occurs. Furthermore, since it is a one-coil shot, the neutral point can be easily regulated.

However, this example corresponds to (i) of the above-mentioned multi-pole type winding connection, and only 1/2 of the output of the 4-pole 7-slot wave winding connection shown in FIG. 5 can be obtained.

(Means for Solving the Problems) As a means for solving this problem, the present invention provides a structure in which an even number of permanent magnets of 4 or more are provided on the stator, and a rotor is provided so as to be rotatable with respect to the stator. .

An odd number of slots provided in the iron core of the rotor are insulated and divided into twice the number of slots, arranged radially around the rotational axis, and those facing each other across the rotational axis are short-circuited. A commutator that rotates integrally with a rotor having a child piece, and a commutator wound between slots of an iron core, and 1! A plurality of coils are wave-wound connected to form a closed circuit for every other commutator piece of the current, and a permanent magnet is connected to the commutator piece of the commutator with a center angle corresponding to the arrangement of the permanent magnets to generate waves. The stator has at least 4 or more permanent magnets in addition to a plurality of wire-wound wires.

A winding method for a small DC motor in which the rotor winding is wave-wound connected, the number of commutator pieces of the commutator is twice the number of slots or the number of coils, and each commutator piece is An object of the present invention is to provide a winding method for a small DC motor in which coils are short-circuited 180 degrees opposite each other, and the coils are wave-wound connected for every other 11ε element of the commutator.

(Function) In the present invention, the commutator pieces in the motor for the multi-pole odd thrower 1 are divided into twice the number of throwers 1 to 1, and the opposing pieces of the commutator pieces are short-circuited. By connecting the coils in wave winding for every other child piece, the coil that is shown from 1 to 1 by the brush is always regarded as 1 coil, and the short coil can be easily matched to the neutral point when switching. Therefore, it is possible to reduce high frequency L'I sound, increase the efficiency of coil utilization, and obtain high output.

(Example) Figures 1 to 3 show an example of the present invention.
The details will be explained below based on the drawings.

FIG. 1 is a schematic diagram of a small 4-pole, 7-slot, wave-wound connected small DC motor according to the present invention, viewed from the axial direction of the motor.

(21) is the four permanent magnets provided in the stator, (
22) is an iron core in the rotor, (23) is a commutator fixed to the rotor, and (24) is a brush provided on the stator.

The iron core (22) is provided with seven slots (S),
Each of the slots (S) has seven coils (L) wound around every other slot (S).
A wave winding connection is provided via a commutator (23) in which the commutator pieces are divided into two.

In addition, in the following explanation, = 1il number, thrower 1~
The ball numbers between (S) and commutator piece numbers are the same as those in the conventional explanation.

The winding method of the coil (L) is 1 as shown in Figures 2 and 3.
For example, connect one end of the coil conductor to the first commutator piece (1), then wind the first coil "1" around both balls [1] [:2], and connect the terminal end of the coil rlJ. , the commutator piece (1) to which the starting end is connected is connected to the second commutator piece (2) adjacent in the advancing direction, and the coil conductor is connected to the second commutator piece (2) and the axis line. Connect to the 9th commutator piece (9) facing 180° around the circumference, and from there connect the 5th coil “5” to both balls [5] [6].
”, and the terminal end of the coil “5” is connected to the tenth commutator piece (10) adjacent in the advancing direction to the commutator piece (9) to which the starting end is connected, and 3 facing the commutator piece (10) to which the conducting wire is connected
Connect to the second commutator piece (3), and then connect to the second commutator piece (3) in the same manner.
In the counterclockwise order shown in Figures (a) and (b), connect the third coil "3" to the 88th coil "8" by wave winding,
The end of the 8th coil “8” is the 1st commutator piece (1)
is connected to form a closed circuit.

As can be seen from the above explanation of the winding order and Figure 3, the odd numbers (1), (2), (3), ... (13)
, or even numbers (2), (4), (6)
,...(14), For either one of the vi current pieces, both ends of each coil are connected between the farthest opposite commutator pieces, and one end is connected to the leading side of the commutator. The other end of the other coil is next to the leading side of the original coil (but
(for either an odd number or an even number), each coil sequentially goes around the thrower 1- every other time and returns to the beginning of the first winding to become a closed circuit.

This is a normal wave winding connection. However, in the case of the present invention, if we look at the entire commutator segments that have been doubled by 1 x 1, we can rewind every other commutator segment, and the commutator segments that have been skipped every other commutator segment are , those in symmetrical positions are short-circuited.

Next, the operation of the rotor connected in wave winding as described above will be explained.

In the figure, the electrodes indicated by (+) and (-) are brushes (24).

The width (W) of this brush (24) is regulated to have a central angle of 172 of the commutator piece.

That is, if S is the number of throwers 1 to 3, then 360°/4s = 90/s' (90°/7 is approximately 12.86° in the case of 7 slots). In the slot wave winding example, a permanent magnet ( 21), but at this time, a high back electromotive voltage (approximately 80% of the peak value) is generated in coil "5" which is shorted at the same time.

At the same time that coil "1" is cut off, coil "5" is also cut off, and you will see the generation of intense sparks.

However, in the present invention, only coil rlJ is short-circuited, and coil "5" is involved in torque generation like the other coils.

Therefore, the switching of the coil by the (-) pole brush is the coil "1".
If the position of the magnet is adjusted so that it is switched only when the back electromotive force generated in coil "1" is 0, it is possible to prevent the generation of sparks.

Also, since only one coil is always shorted, two
The ripples and pulses are twice that of the conventional case for very odd slots (14 x 2 x 2 = 56 pulses for 7 slots).
, the ripples become smoother and smoother, and the starting torque is only affected by the contact resistance between the commutator and the brush, and the ripples in the generated torque depending on the rotation angle completely disappear.

(Effects) As described above, according to the present invention, torque ripple is extremely small, the neutral point can be easily regulated, electrical noise can be reduced, and the life of the motor can be extended, which is extremely advantageous. Moreover, for the same output, only 2/n (n is the number of poles) of the winding of the pattern winding is required, so it is possible to create a motor with the same dimensions and a large output.

In addition, when comparing the two-pole double winding system shown in Fig. 6 and the 4wA wave winding 14'M flow element single winding system according to the present invention for a power of about 30W to 50W and of the same dimensions, it is found that:
With the present invention, an increase in output of about 70% can be seen.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of a small DC motor according to the present invention viewed from the axial direction. Fig. 2 is a wiring diagram showing the connection state between the coil and commutator piece of the motor in Fig. 1; (a) shows when the brush is in the position shown in Fig. 1; Figure 3 is an exploded view of the coil of the motor in Figure 1, Figures 4 to 6 are windings using the conventional winding method, and Figure 4 is a two-pole coil. (a) With a motor with 8 slots and double winding connection,
1 is a schematic view seen from the axial direction similar to FIG. 1. (b) is a wiring diagram of the coil and commutator piece similar to Figure 2, and Figure 5 is for a motor with 2 poles and 7 slot wave winding connections. (a) is a schematic diagram seen from the axial direction similar to Figure 1, (b)
is a wiring diagram of the coil and commutator piece similar to that shown in Figure 2. Figure 6 shows a motor with two poles and seven slots with multiple windings.
A schematic view as seen from the axial direction similar to the figure, and (b) is a connection diagram of the coil and commutator piece similar to FIG. 2. (21) Permanent magnet (22) Iron core (23)
Commutator (24) Brush (S) slot
(L) Coil Fig. 4 IJ (b) Fig. 5 (b)

Claims (2)

[Claims] (1) An even number of permanent magnets of four or more provided in the stator, a rotor provided rotatably relative to the stator, an odd number of slots provided in the iron core of the rotor, and twice the number of slots. A commutator that rotates integrally with the rotor and has commutator pieces that are divided into insulation parts, are arranged radially around the rotation axis, and are short-circuited with opposing pieces across the rotation axis, and between the slots of the iron core. A plurality of coils are wound around each other and are connected in wave winding to form a closed circuit for every other commutator piece of the commutator, and a commutator of the commutator with a center angle corresponding to the arrangement of the permanent magnets. A small direct current motor comprising a pair of brushes that contact the brush and form a power supply circuit in the middle of a closed circuit of a plurality of coils connected in a wave winding manner. (2) A method of winding a small DC motor in which the stator has at least four permanent magnets and the rotor winding is wave-wound connected, the number of commutator pieces of the commutator being the number of slots. Alternatively, the number of coils is twice as many as the number of coils, the commutator pieces that are 180 degrees opposed to each other are short-circuited, and the coils of every other commutator piece of the commutator are connected by wave winding. Winding method for small DC motor.