JPH05336719A - Dc motor - Google Patents

Abstract

PURPOSE:To get a DC motor which can sharply reduce the induced current generated in a short circuit coil, and can reduce vibration or noise by improving the rectifying action thereby. CONSTITUTION:The armature 22 of a DC motor 10 is constituted of twenty one slots 28, with its twenty one pieces of tees 26 given corrugated windings. Field magnets 12, 14, 16, and 18 are arranged in the condition that the center lines are in accord in opposition to the short circuit coils 38, 40, 42, and 44 occurring at unequal intervals in the armature 22. Accordingly, the short circuit coils 38, 40, 42, and 44 do not get in the magnetic fields of the field magnets 12, 14, 16, and 18, so they are not influenced by the magnetic field. Therefore, induced currents (short circuit currents) are not generated in the short circuit coils 38, 40, 42, and 44, and it does not hinder the rectifying action. Hereby, the vibration of a DC motor 10 or the ripple of rotational torque, or noise is sharply reduced, and also the life elongates.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct current motor, and more particularly to a direct current motor using a permanent magnet as a field and having an armature formed by winding odd number teeth and having odd slots.

[0002]

2. Description of the Related Art Among DC motors, a DC motor using a permanent magnet as a field is known. In this type of DC motor, an even number of field magnets are generally fixed inside the motor yoke in a state of facing each other, and further, an armature with a winding is provided inside the field magnet. It is arranged.

In this case, for example, even when four field magnets are used to form a four-pole structure, the number of rectifying brushes can be two, so that an odd number of teeth have wavy windings. Armature is constructed from odd numbered slots.

In such a DC motor, the brush is pressed against each segment of the commutator provided in correspondence with each slot of the armature to feed (rectify) the armature. A short-circuit coil is generated by the brush as it rotates (for example, in the case of a 4-pole 2-brush as shown in FIG. 1, it is at 4 locations). The generation position of this short-circuit coil is uniquely determined by the positional relationship between the armature slot (commutator segment) and the brush, but as described above, an odd number of teeth are wave-wound and odd-numbered. When the armature is composed of slots, the locations where short-circuit coils are generated are not necessarily equidistant along the circumferential direction (in other words, the relative spacings along the circumferential direction are unequal. Will be).

Here, in such a conventional DC motor having a four-pole structure, the four field magnets are arranged at equal intervals (at intervals of 90 degrees) and fixed. Displacement occurs in relation to the above-mentioned short-circuit coil.
That is, the short-circuit coil enters the portion affected by the magnetic field of the field magnet. Therefore, a counter electromotive force (induction current) is generated in the short-circuit coil by electromagnetic induction accompanying the rotation of the armature, and this induction current (so-called short-circuit current) is generated.
Was the cause of hindering the commutation function of the commutator segment and brush.

If rectification is disturbed by the short-circuit current generated in such a short-circuit coil, vibration of the electric motor, fluctuation of the rotating torque, or generation of noise is caused, and a countermeasure for this has been earnestly desired.

In this case, in order to obtain a good rectifying action,
A DC motor has been proposed in which each slot of the armature is displaced in the circumferential direction with respect to each segment of the commutator provided corresponding thereto (for example, Japanese Utility Model Laid-Open No. 61-98237).
No. 9). However, in this DC motor, since each slot is simply and uniformly displaced,
When the armature is constructed from odd-numbered slots by applying the wave winding, the problem (disturbance of rectification) caused by the above-mentioned short-circuit coil still remains.

[0008]

In consideration of the above facts, the present invention can significantly reduce the induced current generated in the short-circuit coil, thereby improving the rectifying function and reducing vibration and noise. The purpose is to obtain a DC motor.

[0009]

In a DC motor according to the present invention, a field magnet is fixed inside a motor yoke, an odd number of teeth are wound, and an armature consisting of an odd number of slots is used as the field magnet. In the DC motor arranged inside the magnet, the field magnet is fixed at a position facing the short-circuit coil whose generation position is uniquely determined by the slot of the armature and the rectifying brush. I am trying.

[0010]

In the DC motor having the above structure, since the field magnet is fixed at a position facing the short-circuit coil, the odd-numbered teeth are wave-wound to form the armature from the odd-numbered slots. Even if the short-circuit coils are generated at unequal intervals along the circumferential direction, the short-circuit coil does not enter the part affected by the magnetic field of the field magnet, in other words, the field magnet has the effect of the magnetic field. Will not be given to.
Therefore, an induced current due to the rotation of the armature is not generated in the short-circuit coil, and the commutation function of the commutator segment and the brush is not hindered.

Therefore, the rectifying action is performed well,
This significantly reduces vibration and noise.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an overall cross-sectional view of a DC motor 10 according to the present invention taken along a direction orthogonal to the axis of rotation. Further, FIG. 2 shows the configuration of the DC motor 10 in a schematic development view.

In the DC motor 10, four field magnets 1
2. The field magnet 14, the field magnet 16, and the field magnet 18 are fixed to the inside of the motor yoke 20 at positions (detailed later), and the field magnets 12, 14, 16, 18 are further fixed.
An armature 22 is arranged inside.

The armature 22 includes the teeth 26 of the core 24.
A corrugated winding is provided between them to form a slot 28. In the present embodiment, the number of teeth 26 is 21, and the slot pitch of the wave winding is 1: 6. In FIG. 1, for convenience of description, short-circuit coils 38, 40 and short-circuit coils 42, 44 described later
Shows only. As shown in FIG. 2, the wave windings of the slots 28 are connected to the commutators 30 each having the number of the segments 32 of 21 and the segment pitch of 1:11. Further, the commutator 30 has a pair of brushes 34,
The brushes 36 are pressed against each other, and the brushes 34 and 36 and the commutator 30 supply power (rectify) to each slot 28. The facing angle between the brush 34 and the brush 36 is 85.7 degrees.

Here, in the armature 22, the odd teeth 26 are wave-wound to form the slots 28, and the brushes 34 are attached to the respective segments 32 of the commutator 30 provided corresponding to the respective slots 28. , 36 are pressed to supply power (rectify), the short-circuit coils 38, 40 and the short-circuit coils 42, 44 are generated as the armature 22 rotates. The short-circuit coils 38, 40, the short-circuit coils 42, 4
4 is due to the positional relationship between the slots 28 of the armature 22 (segments 32 of the commutator 30) and the brushes 34, 36.
As shown in FIG. 1, the generation positions occur every 6 pitches of the teeth 26, and the circumferential intervals of the teeth 26 are not equal.

On the other hand, four field magnets 12 and one field magnet 1
4, the field magnet 16 and the field magnet 18 have the same shape, and the open angles of both ends in the circumferential direction are formed to be 65 degrees.
It is arranged corresponding to the armature 22 having the above-described configuration. Here, the facing angles of the field magnets 12, 14, 16, and 18 (adjacent angles of the circumferential centerline) are the field magnet 12 and the field magnet 1.
4 and 85, between the field magnet 14 and the field magnet 16, and between the field magnet 16 and the field magnet 18.
It is set to 7 degrees, and the distance between the field magnet 12 and the field magnet 18 is set to 102.9 degrees. That is, the field magnets 12, 14, 16, 18 are arranged at unequal intervals, and the short-circuit coils 38, 40 and the short-circuit coil 4 described above are provided.
2 and 44 respectively (in other words, the field magnet 1
2, 14, 16 and 18 are arranged such that the center lines in the circumferential direction thereof match the circumferential center lines of the short circuit coils 38, 40 and the short circuit coils 42, 44).

Next, the operation of this embodiment will be described. In the DC motor 10 having the above-described configuration, the odd-numbered teeth 26 are wave-wound to form the armature 22, and the brushes 34 and 36 are provided to the respective segments 32 of the commutator 30 provided corresponding to the slots 28. Since the power supply (rectification) is performed by pressing the short-circuit coils 38, 4 with the rotation of the armature 22,
0, short-circuit coils 42 and 44 are generated. The short-circuit coils 38, 40 and the short-circuit coils 42, 44 correspond to the slot 28 of the armature 22 (the segment 32 of the commutator 30) and the brush 3.
The position of occurrence of the teeth 26 is uniquely determined by the positional relationship between the teeth 4 and 36, and the teeth 26 are generated at every 6 pitches as shown in FIG.

In this case, in the conventional DC motor 70 having a four-pole structure as shown in FIG. 3, four field magnets are arranged at equal intervals (at intervals of 90 degrees) and fixed. Therefore, a deviation occurs in the relationship with the short-circuit coils 72 and 74. That is, the short-circuit coils 72 and 74 are in a position where they are affected by the magnetic field G of the field magnet. Therefore, an induced current is generated in the short-circuit coils 72 and 74 by electromagnetic induction associated with the rotation of the armature, and this induced current (short-circuit current) hinders the rectifying action of the commutator segment and the brush.

On the other hand, the DC motor 1 according to this embodiment
At 0, as shown in FIG. 2, at the positions facing the short-circuit coils 38, 40 and the short-circuit coils 42, 44, that is, in the state where they coincide with the circumferential center lines of the short-circuit coils 38, 40 and the short-circuit coils 42, 44, respectively. Field magnet 12, field magnet 1
4, since the field magnet 16 and the field magnet 18 are fixed, the odd-numbered teeth 26 are wave-wound and the armature 22 is constituted by the odd-numbered slots 28. Even if the coils 42, 44 are generated at unequal intervals along the circumferential direction, the field magnet 12, the field magnet 1
4, short-circuit coils 38, 40, short-circuit coils 42, 4 in the portions of the field magnet 16 and the field magnet 18 affected by the magnetic field G.
4 does not enter, in other words, field magnets 12, 1
4, 16 and 18 are short-circuit coils 38, 4 which are affected by the magnetic field G.
0, 42 and 44 are not applied.

Therefore, no induced current (short-circuit current) is generated in the short-circuit coils 38, 40 and the short-circuit coils 42, 44 due to the rotation of the armature 22, and the segment 32 of the commutator 30 and the brushes 34, 36 are not generated. It does not hinder the rectification effect of. Therefore, the rectifying action is favorably performed, whereby the vibration of the DC electric motor 10, the fluctuation of the rotational torque, or the noise is significantly reduced. Also, brush 3
It is possible to reduce wear of the motors 4 and 36 and extend the life of the DC motor 10.

In this embodiment, the teeth 26
The slot pitch of the wave winding applied to the field magnets is set to 1: 6, and the open angles of both end portions in the circumferential direction of the field magnets 12, 14, 16, 18 are formed to be 65 degrees. The slot pitch and the circumferential opening angle of the field magnet may be changed in consideration of the adverse effect on the rectifying action.

For example, as in the DC motor 50 shown in FIG. 4, the slot pitch of the wave windings applied to the teeth 52 is set to 1: 5, and the open angles of both end portions of the field magnets 54, 56, 58, 60 in the circumferential direction are set. May be formed at about 60 degrees. Also in this DC motor 50, the short-circuit coil 62,
By fixing the field magnets 54, 56, 58, 60 at positions facing 64 and the short-circuit coils 66, 68, respectively, the short-circuit coil 62 is provided at a portion affected by the magnetic field of the field magnets 54, 56, 58, 60. , 64, short-circuit coils 66, 6
8 will not enter. Therefore, a short-circuit current does not occur in the short-circuit coils 62, 64 and the short-circuit coils 66, 68, the rectifying action is performed well, and the DC motor 5
Vibrations of 0, fluctuations in rotational torque, or noise are significantly reduced.

[0023]

As described above, the DC motor according to the present invention can greatly reduce the induced current generated in the short-circuit coil, which can improve the rectifying function and reduce vibration and noise. It has an excellent effect that the wear of the brush can be reduced and the life of the DC motor can be extended.

[Brief description of drawings]

FIG. 1 is an overall cross-sectional view taken along a direction orthogonal to a rotation axis of a DC electric motor according to an embodiment of the present invention.

FIG. 2 is a schematic development view showing a configuration of a DC motor according to the present invention.

FIG. 3 is a schematic development view corresponding to FIG. 2 showing a configuration of a conventional DC motor.

FIG. 4 is an overall cross-sectional view corresponding to FIG. 1 taken along a direction orthogonal to a rotation axis of a DC electric motor according to another embodiment of the present invention.

[Explanation of symbols]

 10 DC motor 12 field magnet 14 field magnet 16 field magnet 18 field magnet 22 armature 26 teeth 28 slot 30 commutator 32 segment 34 brush 36 brush 38 short circuit coil 40 short circuit coil 42 short circuit coil 44 short circuit coil

Claims (1)

[Claims] 1. A direct current motor in which a field magnet is fixed inside a motor yoke, an odd number of teeth are wound, and an armature consisting of an odd number of slots is arranged inside the field magnet. At a position facing the short-circuit coil whose generation position is uniquely determined by the armature slot and the rectifying brush,
A DC electric motor, wherein the field magnet is fixed.