JP2964417B2 - Commutator device of DC motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] Because of its long life, small torque ripple, good efficiency, no cogging torque, and low inertia, it has a wide range of applications as a drive source.

In particular, it can be used as a drive source for machine tools, robots, and electric vehicles.

[Conventional technology]

A motor having the same principle as a coreless motor is well known.

[Problems to be solved by the present invention]

First Problem Since a coreless electric motor has a coreless rotating armature, it is impossible to make it brushless due to its configuration.

Therefore, the commutator and the brush wear out, and the service life is limited. When the output is several Kw and there is a core, it is said to be about 4000 hours, but in practice, it is about 3000 hours. It is. In the case of coreless, since the inductance is small, the wear due to the spark is small and the end time is several times longer. However, the ball bearing of the rotating shaft has a service life of 40,000 to 50,000 hours, so commutators and brushes of the same service time are required, but it is considered impossible with current technology. Despite other excellent features, its use is limited.

Therefore, it is a technical problem to greatly extend the service life of the commutator and the brush.

Second problem The coreless electric motor has a small output torque.

The output torque is less than 1/2 that of a motor with a core of the same shape.

In addition, since the armature coil is buried and fixed in the cylindrical surface of the cylindrical armature, mass output is lost when the winding density is increased to increase the output torque. .

Therefore, one of the major problems is to increase the winding density, eliminate the drawbacks of the coreless motor, and make the structure mass-producible.

[Means for solving the problem]

First Means A rotating shaft rotatably supported by a bearing provided on an outer housing, a cylinder having the rotating shaft fixed to a center portion of a bottom surface and having a rotating surface on an outer periphery, and a rotating shaft inside the cylindrical surface. , A field pole fixed to an outer casing so that a magnetic flux penetrates the armature coil to obtain an output torque, and a commutator synchronously rotating coaxially with a rotating shaft. And n pieces (n = 2,3,) that are pressed against the commutator rotation surface by a resilient member and supplied from a DC power supply positive electrode that is juxtaposed in the rotation axis direction.
...), the first, second, third,... Positive brushes and a DC power source that is pressed against the commutator surface by a resilient member, is separated from the positive brush by an angle set, and is juxtaposed in the rotation axis direction. The n (n = 2,3,...) First, second, third,... Negative brushes and the first, second, third. The first and second brush holders fixed to the outer casing supporting the respective brushes of the third negative brush so as to be independently slidable in the radial direction of the commutator, and the brush holder by the support shaft. On the outside,
A lever rotatably and resiliently supported to rotate in one direction and one end of the lever pressed against the side surface of the first positive electrode brush so as to be slidable, and the other end of the second positive electrode brush To prevent the brush from being lowered by the resilient member and hold the brush opposite the commutator surface via a small gap, and the first positive brush only for a set length. When worn, one end of the lever fits into a hole provided on the side surface of the brush and moves, so that the other end of the lever escapes from the hole of the second positive electrode brush to remove the brush. A means for lowering and pressing against the commutator surface, and a second means when there are three or more brushes
Holes and levers provided on the side surfaces of the pair of positive brushes so as to perform exactly the same operation on the pair of brushes subsequent to the positive brush, and the first, second, third,. 2 brushes 1
The pair of brushes comprises holes and levers provided on the side surfaces of a pair of negative brushes so that the brushes perform exactly the same operation as the positive brushes.

Second means In the means described in the item (1), m pieces (m = 2, 4,...)
A fixed field magnetic pole composed of N and S magnetic poles, a commutator having 3 / 2m commutator pieces, and a rectangular shape having a width of 180 degrees in electrical angle and a longitudinal direction corresponding to the axial direction of the rotating armature. Armature coil of the first phase and the same shape but different in axial length
2, the armature coil of the third phase and the armature coil of the first phase are arranged side by side on the cylindrical surface of the rotating armature adjacent to each other without any gap.
Means for embedding and fixing the armature coil of the third phase sequentially adjacent to the rotating surface at a position shifted by 120 degrees in electrical angle from the armature coil of the first phase, with no space therebetween. When,
Means for burying and fixing the overlapping portions without swelling inside the rotating surface when each armature common coil overlaps at the end of the rotating armature; And means for obtaining a drive torque by energizing the armature coil with a three-phase Y-type connection by a commutator.

[Action]

As will be described later with reference to FIGS. 7 (a), (b) and (c), the first positive electrode brush 16a is pressed against the commutator 3, but this is worn down and falls, and the coreless coreless output of the Kw class is obtained. In the case of an electric motor, it loses about 1 cm in about 8000 hours, so its function is lost. The commutator in sliding contact is also worn. Therefore, the service life becomes the most intuitive member, and the service life of the motor is determined by the wear of the brush and the commutator.

In the embodiment of the apparatus according to the present invention, the brushes 16a, 16b, 16c are successively replaced by wear and pressed against a new commutator surface, so that the service life is tripled.

 The number of brushes is determined as follows.

The members worn by the motor are the ball bearing of the rotating shaft, the brush, and the commutator.

Therefore, it is reasonable to make the total service time when all of the brushes 16a, 16b,... Used alternately are used, the number of brushes that match the service time of the ball bearings.

The sequential replacement of the brush is performed by levers 23a and 23b shown in FIG.
And a simple and reliable replacement operation is performed. Details will be described later.

High efficiency (5Kw) motor with cylindrical rotating armature
It has a remarkably superior performance compared to other DC motors, such as low inertia and low armature coil inductance, but has a serious drawback in that its useful time is short.

According to the means of the present invention, there is an operation of eliminating such a heavy defect.

A coreless motor having a cylindrical rotating armature has yet another problem.

Since the means for embedding and fixing the armature coil on the cylindrical surface of the cylindrical rotating armature is complicated, mass productivity is lost. This is because there is a contradictory problem that the thickness of the cylindrical portion is made as small as possible and the number of windings of the armature coil is increased in order to keep the strength of the penetration magnetic field large.

The device of the present invention has the effect of solving the above-mentioned problems.

That is, as will be described later with reference to FIGS. 5 (a), (b) and (c), the armature coils are formed into a rectangular shape, and are buried side by side in the cylindrical surface of the armature without any gap.

Accordingly, the linear density is maximized, and a technology capable of mass production is obtained, which has the effect of solving the above-mentioned problems.

〔Example〕

Details of the apparatus of the present invention will be described with reference to the embodiment shown in FIG. All subsequent angle displays are electrical angles.

FIG. 1 is a developed view of the rotating armature 8 and the field pole 1 of the embodiment shown in FIG.

In FIG. 2, side plates 5a and 5b are fitted on both sides of an outer casing 6 made of a cylindrical magnetic material.

A rotating shaft 7 is rotatably supported by bowl bearings 6a, 6b provided at the center of the side plates 5a, 5b, and a right end of a cup-shaped rotating armature 8 is fixed to the rotating shaft. .

Since the armature 8 is cup-shaped, it is generally called a cup-type electric motor.

Reference numeral 10 denotes a cylindrical soft steel yoke which is inserted through an opening at the left end of the armature 8 and is rotatably supported by ball bearings 10a and 10b.

Next, the non-magnetic side plate 8a is mounted, but this member is not always necessary.

The side plate 8a is for preventing the left end of the armature 8 from swaying during rotation. A known means may be used in which the left end of the mild steel yoke 10 is fixed to the side plate 5a, and the rotary shaft 7 is loosely fitted in the central hole.

The commutator 3 is fixed to the right end of the armature 8, and the brush is pressed against the rotating surface. The brush holder is indicated by a dotted line B, and will be described later in detail.

The field magnet 1 is cylindrical and provided with N and S magnetic poles having the same pitch in the circumferential direction. The N and S magnetic poles are opposed to the armature coils embedded in the armature 8, and the magnetic flux is generated by the mild steel yoke 10. Closed.

FIG. 1 shows the above-described field magnet 1 and armature coil.
2a, 2b,... Are developed views of the commutator 3.

The field magnet 1 is 180 degrees wide N, S of equal pitch
The commutator pieces 3a, 3 of the commutator 3 are constituted by magnetic poles 1a, 1b,.
The width of b, ... is 120 degrees.

The armature coil is arranged in the same manner as the three-phase lap winding, but the armature coil becomes an overlapping armature coil, for example, a dotted line 2-1.
Are transferred to the armature coil 2c at the same phase position.

By the above-described transposition means, the armature coils can be arranged at the same pitch as shown in the figure. Such means is provided by the same inventor as Japanese Patent Registration No. 1228205.
And U.S. Pat. No. 4,107,587.

The brushes 13b, 13c are pressed against the commutator 3, and the power supply positive and negative electrodes 4a, 4b
More power is being supplied.

Although the brushes 13b and 13c are separated by 180 degrees, the brush 13c may be replaced with the brush 13a. Brushes 13b and 13a are (360 + 180)
Separated by degrees.

By connecting the respective armature coils and the commutator pieces 3a, 3b,... As shown in the figure, a driving torque is obtained as a three-phase Y-connection motor, and the armature 8 is rotated in the direction of arrow A.

The above-described DC motor has the following excellent features.

Since there is no iron loss, the efficiency is good. If the power is 50 watts or more, the efficiency is 90% or more, and the efficiency is 5% at 97 kW.

Since the rotating armature has no core, it has low inertia and good responsiveness. No cogging torque.

 However, there are two disadvantages.

A first drawback is that the service life is shorter compared to brushless motors.

Compared to a commutator-type motor having a core, a coreless commutator motor has less armature coil inductance and therefore less wear due to spark generation, and its service life is several times longer. However, as described above, the drawback is that the service life is remarkably short in comparison with a brushless motor.

A second disadvantage is that the output torque is low for motors with identical cores.

 Next, the means for removing the first disadvantage will be described.

The cross section of the portion of the brush indicated by symbol B in FIG.
It is shown in the figure.

Brush holders 14a and 14b are inserted and fitted through holes in the outer casing 6. The brushes 16a, 16b, 16c are the positive and negative brushes, respectively.

Since the brush and the brush holder have the same structure for the positive and negative electrodes, the positive brush holder 14a will be described in detail.

Symbols 15a and 15b indicate protrusion guides outside the outer casing 6.

FIG. 7A shows the brush holder 14a viewed from the direction of arrow M.
It is. In FIG. 7 (a), three brushes 16a, 16b, 16c are housed in holes in the brush holder 14a, and are configured to be able to slide up and down.

Although the portion of the brush 16c is shown as being exposed, the other components have the same configuration. The brush 16c is covered with a metal cylinder 30c,
It slides up and down inside the hole 21 and is repelled by a spring (not shown) indicated by an arrow 22c.
Is opposed to the outer peripheral surface of.

The metal plate 20 is affixed to the upper end of the brush holder 14a, and although not shown, the metal plate 20 and the metal cylinder 30c are connected by a flexible conductive wire.

Therefore, by supplying power to the metal plate 20 from the power supply positive electrode, the brushes 16a, 16b, and 16c can all be supplied from the power supply positive electrode.

In this embodiment, the brush has a circular cross section, but may have a square cross section.

FIG. 7 (b) shows only the internal mechanism of the brush holder 14a.

In FIG. 7 (b), metal cylinders 30a, 30b are attached to brushes 16a, 1b.
Covered by 6b. These are slid up and down in the hole like the metal cylinder 30c, and are repelled in the directions of arrows 22a and 22b by a spring (not shown).

Only the brush 16 is pressed against the outer peripheral surface of the commutator 3.

The lever 23a is, as shown in FIG.
The center support shaft 27a is rotatably supported by a bearing (not shown) provided on the brush holder 14a.
The left end of 23a is configured to press the side surface of the metal cylinder 30a and to slide. The right end is fitted into a slit-shaped hole provided on the outer peripheral surface of the metal cylinder 30b to prevent the metal cylinder 30b from descending, and the brush 16b faces the commutator surface via the gap.

A dotted line 24a in FIG. 7 (b) indicates a support shaft of the lever 23a,
Arrows indicate the direction of rotation of the lever 23a by a spring (not shown) that is hung on the support shaft 24a. The force by which the left end of the lever 23a presses the metal cylinder 30a is provided by the spring. The left end of the lever 23a is coated with Teflon to facilitate the above-described vertical sliding of the metal cylinder 30a.

A lever 23b having the same configuration as the lever 23a is also provided on the back surfaces of the metal cylinders 30b and 30c. Hole 23 in FIG. 7 (a)
Is for inserting the lever 23a.

FIG. 7 (c) is an enlarged plan view of FIG. 7 (b) viewed from the direction of arrow N, and the operation will be described using both of them.

 The dotted line 14a indicates the outside of the brush holder.

The support shafts 27a, 27b of the levers 23a, 23b are provided with bearings (not shown) provided outside the brush holder 14a, and are indicated by dotted lines 9a, 9b, 9c,
Shown at 9d. ) So as to be rotatable, and are repelled by springs in the directions of arrows 26a and 26b.

The left end of the lever 23a is pressed against the outside of the metal cylinder 30a,
The right end fits into the slit-shaped hole 28a of the metal cylinder 30b to prevent its lowering.

The left end of the lever 23b is pressed against the outside of the metal cylinder 30b,
The right end fits into the slit-shaped hole 28b outside the metal cylinder 30c to prevent its lowering.

Therefore, the brush 16a is pressed against the commutator 3, and the brushes 16b and 16c are held apart.

The brushes 17a, 17b, 17c and the brush holder 14b on the negative electrode side in FIG.
And the brush 17a is pressed against the commutator 3.

When the operation of the motor is started and about 6000 hours have elapsed, the brushes 16a and 17a are worn by about 1 cm, and the left end of the lever 23a is a slit-shaped hole 25a of the metal cylinder 30a (shown in FIG. 7 (b)). And the lever 23a rotates, and the right end escapes from the slit-shaped hole 28a of the metal cylinder 30b.

Accordingly, the metal cylinder 30b and the brush 16b descend and press against the outer periphery of the commutator 3 to start supplying power.

At this time, since the brush 16a is also in pressure contact with the outer periphery of the commutator 3, the contact resistance becomes unstable as the wear progresses.
There is no problem because the brush 16b is completely pressed. However, when the metal cylinder 30a further descends, the brush holder 14a
It is necessary to suppress the descent by the projection provided in one part of the above.

The operation described above is exactly the same for the brush 17a on the negative electrode side, and is replaced with the brush 17b.

After about 6000 hours, the brush 16b is worn by about 1 cm, and the left end of the lever 23b fits into the slit-shaped hole 25b (shown in FIG. 7 (b)) of the metal cylinder 30b. After rotation, the right end escapes from the slit-like hole 28b (shown in FIGS. 7B and 7C).

Therefore, the metal cylinder 30c is lowered, and the brush 16c is moved to the commutator 3.
And the brushes 16b and 16c are replaced.

The situation described above is exactly the same for the brushes 17b and 17c on the negative electrode side.

A further 6,000 hours of operation is possible, bringing the total service life to 18,000 hours.

This service life is ideally matched with the service life of the bearing of the rotating shaft 7. For this purpose, the number of brushes is preferably determined in consideration of the magnitude of the output, the type of the bearing, the armature current and the like. .

Each time the number of levers 23a and 23b in FIG. 7 (c) is increased by one, the number of brushes 1 can be increased. Practically, the number of brushes juxtaposed is about three to five.

The left and right arms of the levers 23a and 23b in FIG. 7C have different lengths. That is, the reason why the left side is more precise than the right side is that when each lever is rotated, the right end is completely escaped from the slit-shaped hole of the metal cylinder.

As understood from the above description, there is an operational effect that the first disadvantage is eliminated.

 Next, the means for removing the second disadvantage will be described.

FIG. 3 is a development view of a known commutator motor having a three-phase Y-connection as in FIG.

In FIG. 1, the phase transition of the armature coils is performed to remove the overlapping portion of each armature coil, thereby facilitating mass production of the armature. However, the number of armature coils is reduced, and the output coil is reduced. There is inconvenience to do.

In the case of FIG. 3, the output torque increases because the number of armature coils increases, but it becomes difficult to embed the armature coils in the cylindrical armature. This is because the longitudinal ends of the armature coils overlap.

When power is supplied from the positive and negative terminals 4a and 4b, the electronic coils 12a, 12b,... Are supplied with power in the direction of the arrow, and the armature is driven in the direction of the arrow A.

FIG. 4 shows members around the rotary armature 8 of the armature having the above-described configuration, which are indicated by the same symbols in FIG.

The armature 8 has a cylindrical cup shape, and an armature coil is embedded in the outer peripheral surface thereof. The embedding means can be manufactured by injection molding or by inserting an armature coil into a mold, injecting a thermosetting plastic, and heat-curing.

FIG. 5A is a development view of the armature coil embedded in the armature 8.

Each armature coil is wound and solidified by a well-known means which is rectangular and flat.

The solidified armature coil is placed on the cylindrical portion of the armature 8 in the fifth position.
The device is installed as shown in FIG.

The armature coils 12a, 12c, 12e, 12g,... Are adjacent to each other, and the armature coils 12b, 12d, 12f,.

As shown in the figure, the width of the armature coil is set so that a portion effective for torque of the provided armature coil is adjacent to the armature coil and the density of the winding is maximized.

 Therefore, there is an effect that the output torque is maximized.

An enlarged view as seen from the direction of arrow E is shown in FIG. 5 (b). Although only the armature coil 12c is shown, the other armature coils have the same configuration.

The periphery of the portion indicated by the dotted arrow D is shown in FIG. 5 (b).

A portion indicated by a dotted arrow D of the armature coil 12c is formed by being bent upward and protruded as shown in FIG. 5 (b).
Armature coils 12b and 12d are placed below the armature coils 12b and 12d. The same applies to the other armature coils, and the dotted arrow c and other dotted arrow portions protrude upward. Therefore, there is no protruding portion inside the armature 8 shown by the dotted line 8f, and there is a protruding portion only on the outside, and the height is shown by the dotted line 8e.

 The protrusions are indicated in FIG. 4 by the symbols 8c, 8d, 8j, 8k.

Since there is no protrusion inside the left side of the armature 8, the magnetic yoke 10 can be inserted.

Since the thickness of the cylindrical portion of the armature 8 is the distance between the dotted lines 8g and 8f, it is equal to the thickness of the armature coil, and therefore the magnetic resistance of the magnetic flux of the field magnet is minimized.

Therefore, the magnetic field is strong, the output torque is increased, and an armature with good mass productivity is obtained.

FIG. 5C shows another means for obtaining the above-described effects. FIG. 5 (c) shows only the armature coil 12c, but the situation is exactly the same for the other armature coils.

The portions indicated by the dotted arrows J and K of the armature coil 12c and the portions indicated by the other dotted arrows are bent upward and protruded upward, and the armature coils 12b and 12d are mounted on the back surfaces thereof.

 Therefore, the operation and effect are the same as those in FIG.

As will be understood from the above description, there is an operational effect that the second disadvantage is eliminated.

The present invention can be implemented by using a well-known multi-phase lap winding armature.

However, in this case, the conductors of the coil are concentrated at both ends of the armature, and it is difficult to regulate the degree of concentration at a constant level.

It is also difficult to align and embed the armature coil wires with a predetermined thickness on the cylindrical surface of the armature.

Therefore, a problem occurs in mass productivity. However, by adopting the first means according to the present invention, the use time of the commutator and the brush can be greatly extended, which is an effective means.

In the embodiment shown in FIG. 2, the field magnetic poles are provided outside the armature using magnets. However, the field poles may be provided inside the armature, and the outer casing may be made of mild steel to serve as a magnetic path of the magnetic poles.

The present invention can also be implemented by using a field pole formed of a magnetic pole excited by energizing an excitation coil instead of a magnet.

〔effect〕

First effect The advantages of the cup-type coreless electric motor, such as good efficiency, no cogging torque, small rotational inertia, and small torque ripple, are the drawbacks of short-lived service life. The configuration of the commutator and the brush is changed and removed, thereby enabling the operation for the life time corresponding to the bearing of the rotating shaft.

Second effect The winding density of the armature coil buried in the armature is maximized, and the thickness of the buried portion of the armature coil of the cup-shaped armature is made uniform and thin to increase the penetration magnetic flux density. Therefore, the output torque increases.

In addition, a three-phase cup armature that can be mass-produced can be obtained.

[Brief description of the drawings]

1 is a development view of a field magnet and an armature coil of a motor of the device of the present invention, FIG. 2 is a cross-sectional view of the same motor,
FIG. 3 is a development view of a field magnet and an armature coil according to another embodiment of the device of the present invention, FIG. 4 is a sectional view of a main part of the electric motor of the embodiment of FIG. 3, and FIG. (B) and (c) are a development view of the armature coil of the embodiment of FIG. 3 and an explanatory view of a part thereof. FIG. 6 is an axial cross-sectional view of a brush holder.
FIG. 7 is an explanatory view of a brush holder including a brush. 1,1a, 1b, ... field magnets and their magnetic poles, 2-1,2a, 2b, 2c, ... armature coils, 3,3a, 3b, ... commutators and their commutator pieces, 4a, 4b ...... Power supply positive / negative, 6, 5a, 5b ...... Outer casing and side plate, 7 ...
Rotating shaft, 6a, 6b, 10a, 10b Ball bearing, 10 Mild steel yoke, 8, 8a Rotating armature, B, 14a, 14b, 14c Brush holder, 13a, 13b, 13c, 16a , 16b, 16c…, 17a, 17b, 17c…, brush, 12a, 12b, 12c, …… Armature coils, 9a, 9b, 9c, 9d…
Bearing part, 23 ... Hole, 23a, 23b ... Lever, 24a, 24b, 27
a, 27b …… Spindle, 25a, 25b …… Slit-shaped hole, 30a, 30b,
30c: Metal cylinder, 20: Metal plate.

Claims (2)

(57) [Claims] 1. A rotary shaft rotatably supported by a bearing provided on an outer housing, a cylinder fixed to a center of a bottom surface and having a rotation surface on the outer circumference, and an outer peripheral surface of the cylinder. A multi-phase armature coil embedded in the inside, a field pole fixed to an outer housing so that a magnetic flux penetrates the armature coil to obtain an output torque, and a rectifier synchronously rotating coaxially with a rotation axis With the child,
The n (n = 2,3,...) First, second, third,..., N (n = 2, 3,. A positive brush and n pieces (n = 2,3,3) that are pressed from the commutator surface by a resilient member, are separated from the positive brush by an angle set, and are supplied from a DC power negative electrode that is juxtaposed in the rotation axis direction. …) 1st, 2nd,
The third, negative electrode brushes, the first, second, third positive electrode brushes and the first, second
Each of the second, third,... Negative brushes is fixed to an outer casing that supports each of the brushes so that they can slide independently in the radial direction of the commutator.
1, a lever supported by a second brush holder and a support shaft and resiliently supported to be rotatable and rotatable in one direction on the outside of the brush holder, and one end of the lever being a first end. The positive electrode brush is slidably pressed against the side surface of the positive electrode brush, and the other end is inserted into the side surface hole of the second positive electrode brush to prevent the brush from being lowered by the resilient member, thereby forming a slight gap between the commutator surface and the slight gap. One end of the lever fits into a hole provided in a side surface of the brush and moves when the first positive brush is worn by a set length so as to be opposed to each other via the first positive brush. The other end of the lever escapes from the hole of the second positive electrode brush, lowers the brush and presses the brush against the commutator surface, and if there are three or more brushes, two means after the second positive electrode brush. A hole and a hole provided on the side of a pair of positive brushes so that each set of brushes performs exactly the same operation. A lever and a hole provided on a side surface of the pair of negative brushes so that the pair of negative brushes of the first, second, third,... Perform exactly the same operation as the positive brush. A commutator device for a DC motor, comprising: a lever. 2. The method according to claim 1, wherein the fixed field magnetic poles include m (m = 2, 4,...) N and S magnetic poles and 3 / 2m commutator pieces. With a commutator having an electrical angle of 18
A rectangular and flat first-phase armature coil having a width of 0 degrees and a longitudinal direction corresponding to the axial direction of the rotating armature, and second and third-phase armatures having the same shape but different axial lengths. Coils and
The first-phase armature coils are juxtaposed on the cylindrical surface of the rotating armature adjacent to each other without any gap, and the second and third-phase armature coils are sequentially turned on in order from the first-phase armature coils. A means for burying and fixing the rotors adjacent to each other at a position 120 degrees out of phase with no gap and juxtaposed to the rotating surface, and at the end of the rotating armature, when each armature coil is superimposed, the rotating surface The superimposed portion does not bulge inward, but bulges outward and is buried and fixed, and the positive armature brush, the negative armature brush, and the commutator energize the armature coil by three-phase Y-type connection to drive torque. And a commutator device for a DC motor.