JPS5820538B2 - DC machine armature winding - Google Patents

Description

[Detailed description of the invention] This invention relates to an armature winding for a direct current machine that rotates forward and backward.

There are two types of conductor arrangement in the slots of the armature winding: the flatwise method shown in FIG. 1, and the edgewise method shown in FIG.

The latter has a small eddy current loss coefficient and a good space factor, so it has recently been used particularly in vehicle traction motors.
The need to increase capacity within a limited space has led to the increasing adoption of edgewise armature windings.

FIG. 3 shows the conventional arrangement of conductors in the slots of an edgewise electronic machine winding and the conventional connection order with commutator pieces.

One slot has four unit coils, one above the other, with double layer winding, and one coil side A of the same unit coil.

B, C, and D are housed in the upper half of slot S, and the other coil pieces a, b, c, and d are housed in the lower half of slot S2.

Coil sides A, B, C, and D are commutator pieces 1 and 2 of commutator CM.
, 3, 4, and coil sides a, b, c, d are commutator side 2.
, 3, 4, and 5, respectively.

When operating a DC motor connected as described above, the non-spark rectifier may deviate depending on the direction of rotation.

That is, in Fig. 4, if the horizontal axis is the armature current and the vertical axis is the commutator current, the ranges of R and L each represent the non-spark rectified fluid in the case of clockwise rotation, and although they are shifted vertically from each other, Since there is an overlapping portion, sparkless commutation can be achieved in both left and right rotations by adjusting the strength of the interpolation.

However, as shown in Figure 5, if there is a portion that does not overlap between the non-spark rectifying fluids R and L, even if the strength of the interpolation is adjusted, there will be no spark for either left or right rotation. Rectification becomes impossible.

It is recognized that the reason why the sparkless rectification zone shifts depending on the rotation direction as described above is due to the following reason.

In other words, the quality of rectification in a DC machine is generally considered to depend on the quality of the rectification of the unit coil that is rectified last among the unit coils in the same slot, and this can be explained by considering the transient inductance of the coil at the final stage of rectification. Ru.

Since short-pitch winding is generally used in DC machines, other coils in one slot of the coil being rectified may not be short-circuited by other brushes.

The transient inductance of the coil during rectification should be affected by the presence or absence of the short circuit.

To explain this point in detail with reference to FIG. 6, the coil sides in the lower half of the slot S1 are designated as w, x, y, and z from the bottom, and the coil sides in the upper half of the slot S2 are designated as E, F from the top.

G and H, and the other coil sides are the same as in Fig. 3.

21a is a brush, 22a and 23a are brushes of opposite polarity, and when the commutator CM is moving to the right, the slots S1. It represents the brush position at the moment when the rectification of the last unit coil A-a of S2 ends.

Further, 21b and brushes 22b and 23b of opposite polarity represent the brush positions at the moment when the last rectified unit coil D-d completes commutation while rotating in the opposite direction.

During rightward rotation, the coil sides W~2 are not short-circuited, but the coil sides E and F are short-circuited by the brush 22a.

Further, during leftward rotation, coil sides E-H are not short-circuited, but coil sides y and z are short-circuited.

Figure 7 shows the state in which the coil current changes from +1 to -I during the rectification period Tc. Curve a is under-rectification, curve A is over-rectification, and curve C is linear rectification. Generally, linear rectification is performed by interpolation. Therefore, linear rectification is usually taken up as a rectification theory, but in reality it is considered to be in the state of curve a or curve b.

In this case, it is generally said that if the current change at the end of rectification is large and the transient inductance of the rectified coil is large, sparks are likely to be generated from the brush.

However, such spark generation theory ignores the influence of other coils in the same slot, and in reality, changes in the magnetic flux of the coil during commutation are hindered by coils that are short-circuited by other brushes.

Moreover, since the amount of change in this magnetic flux differs depending on the rotation direction,
The value of the transient inductance of the rectified coil also differs depending on the rotation direction, and this is thought to appear as a shift in the non-spark rectification band depending on the rotation direction.

For example, in FIG. 6, when rotating clockwise, coils E and F are short-circuited by the brush 22a at the end of rectification of the A-a coil, so the slot leakage magnetic flux above the coil F in the slot S2 will not change suddenly. Can not.

In other words, the short circuit coils E and F function to prevent sudden changes in magnetic flux.

On the other hand, in the case of counterclockwise rotation, at the final stage of rectification of the coil D-d, the coil sides y and z short-circuited by the brush 23b prevent sudden changes in the slot leakage magnetic flux above the coil area in the slot S1.

In order to examine the influence of the difference in the relative position between the rectified coil side and the short-circuited coil side within the same slot depending on the direction of rotation, it is sufficient to compare the mutual inductance, that is, the mutual permeance, of both coil sides.

As the mutual permeance increases, a sudden change in the slot leakage magnetic flux is prevented, so that the transient inductance of the coil being rectified becomes small, which has a favorable effect on the rectification.

In order to determine the mutual permeance, the dimensions of each part of the slots S1 and S2 are shown in Figure 8 A2, where l is the slot width and h is the slot width.
is the height of the coil side, and f is the isometric height of the wedge insertion part.

As mentioned above, in the case of clockwise rotation, if coil side a is at the end of rectification in slot S2 and coil sides E and F are short-circuited, the mutual permeance between coil side a and El and F will be the same as in the case of counterclockwise rotation. , in the slot S0, the area around the coil is at the final stage of rectification, and the coils y and z are short-circuited, the mutual no-meance between the area around the coil and the coil sides y and z is the total permeance Pl, that is, the counterclockwise rotation is more rectified. should be good, and it also agrees with the actual test results.

Based on the above theory, if the mutual permeance between the coil side at the end of commutation and the coil side short-circuited by another brush in the same slot does not change depending on the rotation direction, the deviation of the non-spark rectification band due to the rotation direction will be resolved. It is considered to be possible.

From this point of view, an object of the present invention is to propose an armature winding for a DC machine that eliminates the deviation of the non-spark rectifying band depending on the direction of rotation by improving the connection order between the coil sides in the slot and the commutator pieces. do.

The embodiment shown in FIG. 9 will be described below. In the present invention, the coil side A in FIG.

Instead of connecting coil sides A, D, B, and C to commutator pieces 1.2, 3.4 in sequence, connect coil sides A, D, B, and C to commutator pieces 1, 2, and 4 in sequence.
3.4, and in the lower half of slot S2, coil side a+albjC is connected to commutator pieces 2 and 3 in sequence.
, 4.5.

Connections are made in the same order for other slots.

In other words, in the upper half of the slot, the coil side that was previously at the bottom is now the second from the top, and in the bottom half of the slot, the coil side that was previously at the top is now the second from the bottom. It is.

In this case, when the mutual permeance is determined in the same way as above, when the rotation is clockwise, the transient inductance is equal to the left and right rotations, and as a result, there is no deviation due to the direction of rotation of the non-spark rectifying band.

The present invention has the above configuration, and has the effect of easily realizing sparkless commutation for both left and right rotations by simply improving the connection order of the coils and commutator pieces.

[Brief explanation of drawings]

Figure 1 shows the arrangement of flat width coils in slots, Figure 2 shows the arrangement of edgewise coils in slots, and Figure 3 shows the arrangement of edgewise coils in standant and the conventional connection order of commutator pieces. 4 and 5 are non-spark rectifying zone curve diagrams, and FIG. 6 is a developed diagram showing the connection between the coil sides and commutator pieces and the brush position in a conventional arrangement similar to that in FIG. 3. , FIG. 7 is an explanatory diagram of current change during rectification, FIG. 8 A is a detailed diagram of the coil side arrangement in the slot shown in FIG. 6, and FIG. 9 is a diagram showing one embodiment of the present invention. This is a similar diagram. Sl, S2-...Slot, Aa, B-
b, C-c. D-d... Unit coil, 1, 2, 3, 4, 5.
... Commutator piece, A, E ... First coil side, B. F...Second coil side, C, G...
・Third coil side, D, H...Fourth coil side, a. W... 1st coil, b, x...
2nd coil, c, y... 3rd coil, d + Z... 4th coil.

Claims (1)

[Claims] 1 The coil sides of the two-layer coil, in which eight unit coils wound edgewise are housed in one slot, are the coil sides of the upper layer coil, the first and fourth coil sides from the slot opening.
For the lower coil sides that are connected to the commutator pieces adjacent to each other in the order of the th, second, and third coil sides, and form unit coils together with the upper coil sides, the first from the slot bottom; Each of the commutator pieces connected to each coil side of the upper layer in the order of the fourth, second, and third coil sides is sequentially connected to the commutator pieces adjacent to each other in the direction of the sequential connection. The armature winding of a DC machine.