JPS5934059B2 - commutator motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a commutator motor and aims to extend the life of carbon brushes and reduce electrical vibrations.

Generally, in commutator motors, in order to extend the life of the carbon brushes, the potential difference between the commutator pieces is made as small as possible to suppress the generation of arcs between the commutator pieces that are in contact with the carbon brushes.

Increasing the number of commutator pieces has been used as a means to suppress the occurrence of the above-mentioned arc, but if the number of commutator pieces is increased,
With the increase in cost, lack of mechanical strength, difficulty in manufacturing, etc., the number of commutator pieces has to be reduced to a certain economical number (
(approximately 20 sheets at 100V).

For this reason, the life of the carbon brush has naturally been limited.

Further, the commutator motor is constructed as shown in FIGS. 1 to 3.

FIG. 1 shows an armature of a commutator motor. As shown in the figure, an iron core 2 is press-fitted into a shaft 1, and a commutator 3 is press-fitted onto one side of the shaft 1 at a position slightly apart from the iron core 2.

Furthermore, the iron core 2 has winding slots 4 formed on its outer periphery, and each slot 4 is provided with a winding 5.
The starting and ending ends of the winding are connected to the commutator 3.

Further, the carbon brushes 6 are applied to the commutator from the left and right sides.

The wire connections and windings of this armature are as shown in FIGS. 2 and 3. In other words, the coil a1, which has started winding after coming out from the commutator piece 3a, is wound into the slots 4a and 4d and becomes the commutator piece 3d. Then, the coil b coming out from the commutator piece 3c
1 is wound into the slot 4b and the slot 4e and ends up in the commutator piece 3d.

The winding is repeated in sequence as described above.

By the way, in the actual armature winding, it is not possible to wind all the coils 5 in the many slots 4 of the armature at the same time, so as mentioned above, the first coil is wound, then the second coil is wound in the next slot. The windings are sequentially applied to the coils while rotating the armature core 2, but the position of the windings wound around each slot in the slot is as follows: When there is one coil per slot, the electrical However, in the coil end part 7, the coil at the beginning of winding is located near the iron core, and the last winding is in the coil end part I, which is farthest from the iron core. .

(See Figure 1) Therefore, the average coil diameter was different between the first coil and the last coil, resulting in a difference in resistance value.

That is, as shown in FIG. 4, the resistance value gradually increases from the coil a1 at the beginning of winding, and returns to its original value at the last coil c2, resulting in an extreme change at the end.

For this reason, when the motor rotates, the carbon brush 6
The circulating current flowing between the two short-circuited commutator pieces 3 depends on the resistance value of each coil, assuming that the back electromotive force due to the transformer action of the armature is the same in each coil.

Because of this circulating current, the carbon brush generates heat and arcs are generated, but this circulating current also changes depending on the coil resistance mentioned above, so the amount of arcing changes depending on the rotational position of the commutator. However, the commutator wears unevenly, and mechanical steps occur in the commutator pieces.

As a result, the generation of arcs becomes even more pronounced, and the life of the carbon brushes is shortened one after another.

In order to solve the above problems, the present invention attempts to extend the life of carbon brushes by changing the winding diameter.

In other words, the wire diameter is gradually increased from the coil a1 at the beginning of winding to the coil c2 at the end of winding, the difference in resistance is reduced and the range is within ±5 coefficients, and the circulating current generated in the coil is kept constant. This was done so that there would be no

Then, as shown in FIG. 5, the resistance value of each coil without any change was obtained.

It should be noted that if the value exceeds the factor of ±5, this effect will be so small that it will become meaningless.

According to this coil winding configuration and characteristics, even if the commutator position changes as the motor rotates, the carbon brushes generate less heat, arc fluctuations are small, and uneven commutator wear is significantly reduced. However, the step difference in the commutator pieces is also reduced.
There will be no more severe deterioration in the middle of the life of the carbon brush, and the life will no longer fall far short of the originally expected life.

For the same reason, the armature reduces electrical oscillations because there is no continuous fluctuation in the current flowing through it.

For convenience of explanation, six slots and six segments are used as an example, but the same effect can be obtained even if the number of slots or the number of segments changes.

As described above, according to the present invention, the life of carbon brushes can be extended and electrical vibrations can be reduced, which has great industrial effects.

[Brief explanation of the drawing]

Figure 1 is an external view of the armature of a commutator motor, Figure 2 is a circuit diagram of the armature winding, Figure 3 is a partial sectional view of the armature, and Figure 4 is a partial cross-sectional view of the armature.
The figure is a resistance change diagram of a conventional armature coil, and FIG. 5 is a resistance change diagram of an armature coil according to the present invention. 2... Iron core, 3... Commutator, 4...
...Slot, 5...Winding, 6...
Carbon brush, al, bl...Coil, 3a
, 3b... Commutator piece, 4a. 4b...Slot.

Claims (1)

[Scope of Claims] A commutator motor in which, in an armature winding having 13 or more slots, the change in resistance value of each coil is within ±5 fb of the resistance value of each coil by changing the wire diameter of the coil. 2. The commutator motor according to claim 1, wherein the wire diameter increases from the coil at the beginning of winding to the coil at the end of winding.