JPS6311894Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a small DC motor having a configuration in which the field magnet has four poles and the number of commutator pieces and the number of changing magnetic poles of the commutator are six.

Conventionally, this kind of small DC motor was developed in 1974.
There is something like the one described in No. 12522. As illustrated in FIG. 1, the field magnet 2 of the small DC motor 1 consists of four poles 2a, 2b, 2c, and 2d, and the variable magnetic poles of the armature 3 are 3a, 3b, and 3c.
Consists of individuals. The commutator 4 has commutator pieces 4a, 4b...4
An armature coil 5a wound around the variable magnetic pole 3a is connected between the commutator pieces 4e and 4a, and an armature coil 5b wound around the variable magnetic pole 3b is connected between the commutator pieces 4a and 4c. Changeable magnetic pole connected between 3
The armature coil 5c wound around the armature coil 5c is connected between the commutator segments 4c and 4e. and commutator piece 4
a and 4d are short-circuited, commutator pieces 4b and 4e
However, the commutator pieces 4c and 4f are also short-circuited. Such a small DC motor 1 has at least four field poles 2a, 2b, 2c, and 2d, compared to a conventional small DC motor that has two field poles and three variable magnetic poles. Because I am doing
The opening angle of each magnetic pole is 90 degrees, and the close proximity of each variable magnetic pole to the field creates a large attractive force and generates a strong rotational force. Also armature coil 5
b, 5c are energized, the changing magnetic pole 3b
receives attraction and repulsion from the field poles 2b and 2c at the same time, and the changing magnetic pole 3c also receives attraction and repulsion from the field poles 2c and 2d at the same time, so in addition to the above-mentioned rotational force, a high rotational torque is generated. It has the characteristics that can be obtained.

However, when looking at the magnetic attraction force in the radial direction, the changing magnetic pole 3a receives an upward force 6a from the field pole 2a in the state shown in FIG.
b and 2c receive force 6b in the diagonal upper right direction,
The variable magnetic pole 3c receives a force 6c in the diagonally upper left direction from the field poles 2c and 2d. These forces 6a, 6
When b and 6c are combined, a large upward force 6 is generated, and the armature 3 is pulled upward. Next, in the state shown in FIG. 2, the variable magnetic pole 3b is
b receives a rightward force 7b, and the changing magnetic pole 3c receives a diagonally lower rightward force 7c due to field poles 2c and 2d.
In response, the changing magnetic pole 3a receives a force 7a in the diagonally upper right direction from the field poles 2a and 2d. These forces 7
Combining a, 7b, and 7c produces a large force 7 in the right direction
Therefore, the armature 3 will be pulled to the right. The magnitude of the force applied to the armature 3 changes from force 6 to force 7 as the armature 3 rotates. In this way, the armature 3 detects rotation and receives radial forces that differ in the forward direction, and as the armature 3 is swung in each direction, the axis of rotation of the armature 3 (not shown) The impact between the bearing and the inner bore of the bearing (not shown) generated a large amount of noise from the bearing, which had a fatal drawback that made it impractical.

In view of the above-mentioned drawbacks, the purpose of the present invention is to develop a small DC motor that can eliminate the noise generated between the rotating shaft of the armature and the bearing with a simple configuration without losing the characteristics of obtaining a large rotational force. It is about providing.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 3, the armature 8 has six variable magnetic poles 8.
Coils 9a, 9b, 9 consisting of armature coil 9, consisting of a, 8b, 8c, 8d, 8e, 8f.
c, 9d, 9e, and 9f are wound respectively. The commutator 10 has commutator pieces 10a, 10b, 10c, 1
A brush 11 consisting of six brushes 0d, 10e, and 10f and two contact pieces with a mechanical opening angle of 90 degrees is in sliding contact with the circumferential surface of the commutator 10. The field poles 12 are field poles 12a, 12b, 12c, 12d.
It consists of four poles, and the N and S poles are alternately magnetized. The coils 9a and 9d are connected in series and are each wound around the variable magnetic pole 8a and the variable magnetic pole 8d located symmetrically thereto, and each coil end 9a' and 9d' is connected to a commutator piece 10, respectively.
f and 10d. Furthermore, coil 9
b and 9e are connected in series and change magnetic poles 8b and 8e
The coil ends 9b' and 9e' are connected to commutator bars 10b and 10d. Further, coils 9c and 9f are also connected in series in the same manner as described above, and are wound around variable magnetic poles 8c and 8f. In this way, the armature coil 9 consists of two coils 9a and 9.
It is composed of six coils which are Δ-connected by d, 9b and 9e, and 9c and 9f. Note that commutator bars 10a and 10d are short-circuited, commutator bars 10b and 10e are short-circuited, and commutator bars 10c and 10f are short-circuited.

FIG. 4 shows a cross-sectional view of the structure of the small DC motor 13 of the present invention, in which a thruster, a washer 15 and a bearing 16 are fitted and fixed in the central concave portion 14a of the side plate 14, and the inner end surface 14b is fitted with a thrust washer 15 and a bearing 16. holds an insulating plate 17, on which are mounted brush terminals 13, 18 to which the brush 11 is fixed, and arc-extinguishing elements (not shown) such as a chiyoke coil. A cylindrical field pole 12 that is magnetized into four poles and constitutes field poles 12a, 12b, 12c, and 12d is fitted and fixed on the inner periphery of 19 into which the side plate 14 is fitted, and the bottom inner hole 19a A bearing 20 is fitted and fixed to. An armature 8 in which a rotating shaft 21 is supported by both bearings 16 and 20.
The armature core 8g that constitutes the variable magnetic poles 8a, 8b...8f, the armature coils 9a, 9b...9f wound around the variable magnetic poles 8a, 8b...8f, and the armature coils 9a, 9b...9f commutator pieces 10a, 10 which are connected and come into sliding contact with the brush contact pieces 11a, 11b.
b...consisting of a commutator 10 with 10f. The commutator pieces 10a, 10b...10f are held on the circumferential surface of the insulating holder 21, and the commutator pieces 10a...
An arc-extinguishing element board 22 is connected and fixed to risers 10a'...10f' extending from...10f. Note that 23 and 24 are collars made of synthetic resin.

In this way, the electrical angle of the coils 9a and 9d is 2π
Because of this position, the rotational torque obtained by each coil 9a, 9d is in the direction of the arrow. Also, the relationship between coils 9b and 9e and coils 9c and 9f is at a position of 2π in terms of electrical angle, and all rotational torque is generated in the direction of the arrow. Rotates with torque. As for the magnetic attraction force in the radial direction, as shown in FIG. 5, the variable magnetic pole 8a receives an upward force 25 from the field pole 12a. The changing magnetic pole 8b is the field magnetic pole 12
a and 12b, the changing magnetic pole 8c receives a force 27 in the diagonally upper right direction from the field poles 12b and 12c, and the changing magnetic pole 8d receives a downward force 28 from the field pole 12c. The variable magnetic pole 8e receives a force 29 diagonally upward to the left by the field poles 12c and 21d, and the variable magnetic pole 8f receives a force 30 diagonally downward to the left by the field poles 12d and 12a. The variable magnetic poles 8a and 8d are mechanically symmetrical at 180 degrees, and the variable magnetic poles 8b and 8e
The variable magnetic poles 8c and 8f are also mechanically located at 180° symmetrical positions. Therefore, the variable magnetic poles 8a...8f are the field poles 12a, 12b,
The vector sum of the forces 25 to 30 received from 12c and 12d is 0.

Even when the rotational position of the variable magnetic poles 8a...8f changes, the vector sum of the forces received by each variable magnetic pole 8a...8f is always zero.

Therefore, the armature 8 is not subjected to any change in radial force by the field poles 12, the armature 8 does not vibrate, and no noise is generated from the bearing due to this vibration.

According to the present invention explained above,
The small direct current motor described in Japanese Patent No. 12522 maintains the characteristics of the small DC motor, that is, the ability to obtain high rotational torque, while preventing noise from the bearings, which was a drawback of this motor. By the way, as a result of actual measurements,
While the noise level of the entire conventional motor was 46 dB, the noise level of the entire motor of the present invention was 32 dB, an improvement of 14 dB.

In addition, since there is no armature vibration, the sliding contact between the brush and commutator is stable, reducing electrical noise.Furthermore, the bearing, commutator, and brush can have a long lifespan, so there is no deterioration over time. And it can be rotated quietly.

Moreover, since the number of variable magnetic poles has been increased, the number of turns of the coil per pole can be reduced, so the thickness of the coil (dimension W shown in Figure 4) can be reduced, and the axial dimension can be increased. By making it smaller, a flat electric motor can be obtained. Since the coils for two changing magnetic poles are connected in series, by winding two coils in succession with one wire, the number of places where the coils are connected to the commutator pieces can be reduced by half. Workability is also improved.

[Brief explanation of the drawing]

Figure 1 is a diagram of a conventional small DC motor with 4 field poles and 3 variable magnetic poles, Figure 2 is an illustration of the force that the variable magnetic poles receive from the field pole, and Figure 3 is the present invention. FIG. 4 is an assembled sectional view of the small DC motor of the present invention, and FIG. 5 is an explanatory view of the force that the changing magnetic pole of the small DC motor of the present invention receives from the field pole. 8... Armature, 8a, 8b... 8f... Variable magnetic pole, 9... Armature coil, 9a, 9b... 9f...
Coil, 10...Commutator, 10a, 10b...10
f... Commutator piece, 11... Brush, 12... Field pole.

Claims (1)

[Scope of utility model registration request] An electric machine having a field magnet in which four poles are alternately magnetized as N and S poles in the circumferential direction, and having a rotating shaft at the center and six variable magnetic poles facing the field magnet and arranged at equal intervals in the circumferential direction. and an armature coil consisting of six coils wound by connecting two coils in series for each variable magnetic pole that are mechanically symmetrical at 180 degrees to each other, and each two coils are shorted to each other. A commutator having six commutator pieces arranged circumferentially and sequentially connected to every other commutator piece for each of the two coils, and a 90° opening mechanically connected to the commutator pieces. A small DC motor consisting of a pair of brushes that slide into contact at an angle and a bearing that supports the rotating shaft.