JPH0258855B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an armature for a commutator rotating electric machine, and more particularly to an armature having a short-pitch wound armature coil.

In general, commutator motors have a motor rotation speed of approximately
Since the speed is extremely high at 20,000 to 30,000 rpm, iron loss accounts for a high proportion of motor losses. Also, vacuum cleaners,
Winding work for armature windings in mass-produced products such as power tools is mainly done automatically by machines. The slot shape of this type of commutator motor is often a semi-closed slot with a wide open side and a narrow bottom, and in such a slot shape, the conductor space factor at the bottom of the slot is poor. If the bottom of the slot is widened to improve the conductor space factor within the slot, the cross-sectional area of the teeth decreases, which increases the magnetic flux density of the teeth, increases core loss, and results in an inefficient motor. These points will be explained below with reference to the drawings.

FIG. 1 shows the armature of a commutator motor. An armature core 2 is press-fitted into the shaft 1, and a commutator 3 is placed on one side of the shaft 1 at a position slightly apart from the armature core 2.
is press-fitted. The commutator 3 has a riser 4, and the riser 4 is formed with a slit 5 for inserting the coil end. Furthermore, slots 6 for winding are formed on the outer periphery of the armature core 2, and armature coils 7 are provided in each of the slots 6, and the starting and ending ends of each coil are inserted into the slits 5 of the riser 4 mentioned above. and connected. And on the surface of commutator 3
A pair of carbon brushes 8 are brought into contact at a pitch of 180 degrees.

The armature coil 7 is wound in the slot position shown in FIG. That is, the armature coil 7 is a short-pitch winding with one slot for rectification, and the armature coils 7a and 7b are wound around a pair of slots 6a and 6f by an automatic winding machine (not shown). Ru.

That is, the armature coil 7a has a pair of slots 6
a and the bottom of the slot 6f, and the armature coil 7 is wound around the bottom of the slot 6f.
The upper winding coil is wound above the lower winding coil on the open side of the slot a and the slot 6f.

FIG. 3 shows a cross section of the slot 6a after winding. A lower coil 7a and an upper coil 7b are wound inside the slot insulating paper 10 in the slot 6a, and a wedge 11 is placed above the coil 7a to prevent the lower coil 7a and upper coil 7b from jumping out of the slot 6a. has been inserted. 9 is Teisu, V
is the tooth width, and 12 is a space formed between the inner surface of the slot 6a and the lower coil 7a.

When the slot shape is a semi-closed slot like this, the upper coil 7b wound on the open side of the slot 6a is wound with the wires of the coil being relatively closely contacted, but the slot width is narrower. Since the lower coil 7a wound on the bottom of the slot 6a has the same wire diameter as the upper coil, the space 12 formed as shown in the figure becomes larger, and the conductor space factor at the bottom of the slot decreases. do. When the conductor space factor decreases, the area of the slot for winding the upper and lower coils with a predetermined number of turns increases. When the slot area increases in this way, the teeth width W naturally becomes narrower, the magnetic flux density of the teeth increases, the core loss increases, and the efficiency of the motor decreases.

On the other hand, the present inventors have already proposed a rotating electric machine described in Japanese Patent Application Laid-Open No. 54-50904 as a method for reducing core loss without changing the cross-sectional areas of the upper and lower coils.

This has a slot formed of an upper wide part and a lower narrow part, and in particular, a part of the lower conductor inserted into the lower narrow part is plastically deformed into a narrower width by pressing.

As a result, the conductor space factor of the lower coil with respect to the lower narrow portion is significantly improved, and the width W of the root portion of the teeth can be increased, so that iron loss is significantly reduced.

However, this configuration has the problem that the shape of the slot is complicated and that the lower coil needs to be plastically deformed into a flat shape, making processing extremely troublesome.

Furthermore, even with such a configuration, the cross-sectional area of the lower coil does not decrease, so the impedance remains the same, and no improvement in rectification performance can be expected.

As another method for reducing iron loss, the lower coil 7a,
It is conceivable to reduce the coil wire diameter of the upper coil 7b, but in this case, the increase in steel loss will be greater than the decrease in iron loss, resulting in an inefficient motor. Also, it is conceivable that the lower coil 7a and upper coil 7b are two coils with a small wire diameter, and the lower coil 7a and upper coil 7b have two coils, but if they are made with two coils, winding can be done with two coils. The drawback was that a new automatic winding machine had to be manufactured. In addition, since the lower coil 7a is wound at the bottom of the slot, the slot leakage inductance increases and the upper coil 7b
Since the coil is wound on the open side of the slot, the slot leakage inductance is reduced, which causes a difference in rectification performance between the upper and lower coils.
In particular, it also has the disadvantage that the rectification performance of the motor is influenced by the rectification performance of the lower coil.

Furthermore, the present invention aims to use short-pitch winding as the coil winding method to improve rectification performance, increase overall output, and extend life. The invention does not discuss these matters.

Furthermore, in the case of a relatively small-sized rotating electrical machine to which the present invention is applied, mass productivity is particularly strictly pursued, but the above-mentioned patent publication that we are proposing does not particularly discuss manufacturability.

An object of the present invention is to eliminate the drawbacks of the prior art described above, improve the conductor space factor in the slot of the armature core, and reduce iron loss even when a relatively simple single-wire winding machine or an automatic winding machine is used. An electric machine for a rotating electric machine with a commutator that can improve the rectification performance of the motor by equalizing the rectification performance of the upper winding coil and the lower winding coil, increasing the brush life, and further improving the winding workability. It is to provide a child.

In order to achieve these objects, the present invention provides an armature core having a large number of slots each having a wide open side and a narrow bottom. In the armature of a commutator rotating electric machine, the armature coil is provided with a pair of slots, and a brush is in sliding contact with the surface of the commutator. The lower winding coil is wound in short intervals and placed at the bottom of each slot, and the lower coil is wound in short intervals across a pair of slots, and is wound in advance on the open side of each slot. an upper winding coil wound above the lower winding coil, the starting and ending ends of the lower winding coil are connected to two predetermined adjacent commutator pieces of the commutator, and the starting and ending ends of the upper winding coil are connected to two predetermined adjacent commutator pieces of the commutator. The lower coil and the upper coil are connected to two predetermined adjacent commutator pieces, and the lower coil and the upper coil are made of wire having a circular cross section, and the wire diameter of the lower coil is smaller than the wire diameter of the upper coil. It consists of an armature.

Hereinafter, one embodiment of the configuration of the present invention will be described based on the drawings.

FIG. 4 is a cross-sectional view of a slot 6a portion in which an upper coil and a lower coil having a circular cross section and different wire diameters are wound as a short section winding in one slot. At the bottom of the oval-shaped semi-closed slot 6a is a lower winding coil 7a with a thin wire diameter.
An upper coil 7b having a thick wire diameter is wound on the open side of the slot 6a. When the lower winding coil 7a of a thin wire diameter is wound at the bottom of the slot in this way,
The space 12 created at the bottom of the slot becomes smaller,
This creates a new space 1 on the open side of the slot.
3 occurs. The area of this space 13 becomes larger than the reduction in the cross-sectional area of the coil due to the increase in the conductor space factor at the bottom of the slot.

FIG. 5 shows a sectional view of the slot 6a portion in which the tooth width W is increased so that the space 13 is eliminated. Here, since the teeth width W is in the relationship W>W, the cross-sectional area of the teeth increases, the magnetic flux density of the teeth decreases, and iron loss decreases. Copper loss increases by using a coil with a smaller wire diameter for the lower winding coil 7a, but since the conductor space factor in the slot improves by more than the increase in copper loss, the decrease in iron loss becomes larger and the overall loss decreases. This has the effect of increasing the efficiency of the electric motor.

Furthermore, since the lower coil 7a is made of a coil with a smaller wire diameter, the electrical resistance of the lower coil increases. When the resistance of the lower coil increases, the short-circuit current that flows through the lower coil when it is being rectified by the brush decreases, improving rectification performance and improving the power factor. Furthermore, since the short-circuit current is reduced, sparks generated between the brush and the commutator are reduced, making it possible to extend the life of the brush.

On the other hand, by using short-pitch winding as the armature winding method and by making the wire diameter of the lower winding coil smaller than that of the upper winding coil, further improvement in rectification performance can be achieved.

Also, unlike full-pitch winding, which has a slot angle of 180 degrees, short-pitch winding is characterized by the relative slot angle for winding each coil being less than 180 degrees. Thus, two windings can be wound simultaneously using two winding machines (flyers). That is, this is because the two windings do not interfere during the winding operation. Furthermore, this means that one winding machine can be used to wind a large-diameter upper-wound coil and the other winding machine can be used to wind a smaller-diameter lower-wound coil, and full-pitch winding allows for setup changes such as changing the wire diameter. By using short-pitch winding, what was previously required is no longer necessary, and it may be possible to improve the workability of the winding. In particular, in the present invention in which the wire diameters of the upper and lower coils are different, short-pitch winding has technical significance from the viewpoint of improving winding workability.

FIG. 6 shows the state of connection between the riser and the armature coil when wires of different diameters are used as the armature coil. In FIG. 6, 3 is a commutator, 4 is a riser, 5 is a slit provided in the riser 4, 7a is a lower winding coil, 7b is an upper winding coil, and 14 is a piece of mica. Here l is the thickness of the upper part of riser 4, l
is the thickness of the lower part of the riser 4, and if armature coils 7 of the same wire diameter are used, it is necessary to form the slits 5 in parallel, so the thickness l of the lower riser piece becomes thinner and l>l. . l>l
Then, the mechanical strength of the riser 4 of the commutator 3 is l
Therefore, the riser 4 cannot be made smaller, and the commutator 3 cannot be made smaller. However, if armature coils with different wire diameters (upper and lower coils) are used as in this embodiment, the thin wire diameter coils (starting and ending ends of the lower coil) are placed at the bottom of the riser slit 5. , the thickness l of the riser 4 can be made almost the same as the thickness l. This increases the mechanical strength of the riser 4, making it possible to downsize the riser 4 and, by extension, the commutator 3. Note that when the riser piece thickness is set to l=l, the shape of the slit 5 becomes tapered, and as described above, the conductor space factor is improved and the efficiency of the motor is improved.

FIG. 7 is a diagram showing the winding state of the upper and lower coils, showing an application example where two or more coil sides are wound within one slot. When the number of coil sides in one slot is two or more, the coil that finishes rectification last in the same slot will have poor rectification, which will be a factor in shortening the life of the brush. The one shown in Fig. 7 is an example in which the number of coil sides is two in one slot, and the coil that is finally rectified is the commutator piece 3b,
The lower coil 7a is connected to the commutator 3c, and the coil that finishes rectification first is the upper coil 7b connected to the commutator pieces 3a and 3b. In this embodiment, when two types of coils with different wire diameters are used in the armature coil 7, the lower winding coil with a smaller wire diameter has a large resistance, so by making the lower winding coil 7a, which is last rectified, with a smaller wire diameter. , the short circuit current flowing through the coil can be reduced, the rectification can be improved, and the brush life can be improved.

As explained above, according to the present invention, the armature core has a large number of slots each having a wide open side and a narrow bottom, and each armature coil wound in the slot of this armature core serves as a commutator. In the armature of a commutator rotating electrical machine, the armature coil is provided with an armature winding connected in series through a commutator, and a brush that is in sliding contact with the surface of the commutator. a lower winding coil which is wound in short intervals and placed at the bottom of each slot;
The coil is wound in short intervals across a pair of slots, and is wound on the open side of each slot and above a pre-wound lower coil. The ends are connected to two predetermined adjacent commutator pieces of the commutator, and the starting and ending ends of the upper winding coil are connected to two predetermined adjacent commutator pieces.
The lower winding coil and the upper winding coil are connected to two commutator pieces, and the lower winding coil and the upper winding coil are made of wire rods having a circular cross section, and the lower winding coil wire diameter is configured to be smaller than the wire diameter of the upper winding coil. To provide an armature for a commutator rotating electric machine that improves the conductor space factor, reduces iron loss, improves the rectification performance of the motor, extends the life of brushes, and can be expected to improve winding workability. It is something that can be done.

[Brief explanation of the drawing]

Fig. 1 is a perspective view showing the overall structure of the armature of a commutator motor, Fig. 2 is an explanatory drawing showing the winding position of the armature coil, and Fig. 3 is a sectional view showing the vicinity of the slot portion of a conventional armature. , FIGS. 4 and 5 are cross-sectional views of main parts showing the vicinity of the slot portion of an armature according to each embodiment of the present invention, and FIG. 6 is a commutator and armature of an armature according to an embodiment of the present invention. FIG. 7 is a side view showing the coil connection structure, and is a diagram showing the armature coil position and connection state of the armature to the commutator according to an embodiment of the present invention. 6a... Armature core slot, 7a... Lower coil, 7b... Upper coil.

Claims (1)

[Scope of Claims] 1. An armature core having a large number of slots each having a wide open side and a narrow bottom, and each armature coil wound within the slots of this armature core are connected in series via a commutator. In the armature of a commutator rotating electric machine, the armature coil is provided with an armature winding configured to have an armature winding and a brush that is in sliding contact on the surface of the commutator. The lower winding coil is wound and placed at the bottom of each slot, and the lower winding coil is short winded across a pair of slots and is on the open side of each slot and is pre-wound. an upper-wound coil arranged on the upper side, the start and end of the lower-wound coil are connected to two predetermined adjacent commutator pieces of the commutator, and the start and end of the upper-wound coil are connected to two predetermined adjacent commutator pieces. A commutator rotating electric machine, characterized in that the lower coil and the upper coil are made of wire rods having a circular cross section, and the wire diameter of the lower coil is smaller than the wire diameter of the upper coil. armature. 2. In the product described in claim 1, if the number of coil sides in one slot is two or more, the armature coil in the same slot that finishes rectification last is the lower winding coil, and the rectification is finished first. An armature for a commutator rotating electrical machine, characterized in that the armature coil is a top-wound coil.