JPH08168223A - Dc machine - Google Patents

Abstract

PURPOSE: To provide a d.c. machine that achieves increase in output and yet increase in rotational speed. CONSTITUTION: A d.c. machine for use in starters has six main magnetic poles 24a-24f in its yoke 13, and first auxiliary magnetic poles 25a-25c for canceling out leakage flux between magnetic poles, are placed between equally spaced three magnetic poles. Second auxiliary magnetic poles 26a-26c for canceling out the magnetomotive force of armature coils, are placed between the remaining three magnetic poles. The first auxiliary magnetic poles 25a-25c cancel out leakage flux between the magnetic poles, and the effective flux of the main magnetic poles 24a-24f is thereby increased, which increases the output of the d.c. machine 4. The second auxiliary magnetic poles 26a-26c cancel out the magnetomotive force of the armature coils, and the reactance voltage of the armature coils is thereby canceled out. This prevents voltage drop between a brush and a commutator, and thus the reduction of the rotational speed of the d.c. machine 4. Thus, the combination of the first and second auxiliary magnetic poles, achieves increase in output and yet increase in rotational speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC machine in which a leakage magnetic flux between the main magnetic poles is canceled by an auxiliary magnetic pole arranged between the magnetic poles to suppress the leakage magnetic flux and increase the effective magnetic flux of the main magnetic pole.

[0002]

2. Description of the Related Art A DC machine of this type is disclosed in Japanese Patent Laid-Open No. 50-6.
The technique disclosed in Japanese Patent No. 5804 is known. In the DC machine disclosed in this publication, auxiliary magnetic poles whose polarities are opposite to those of the main magnetic poles on both sides are arranged between the main magnetic poles to suppress leakage flux between the main magnetic poles. The effective magnetic flux from the magnetic pole to the armature coil via the gap is increased. With this technique, the output can be increased without changing the external dimensions of the DC machine. Moreover, by using this technique, the external dimensions can be reduced without changing the output of the DC machine.

[0003]

For example, in a starter for starting an engine, there is a demand for downsizing a DC machine. When it is desired to reduce the size of the DC machine to obtain a predetermined output torque, for example, it is conceivable to increase the rotation speed of the DC machine and decelerate the rotation output with a speed reduction mechanism. However, when the rotation speed of the DC machine is increased, a loss occurs during the rectification due to the reactance voltage generated in the armature coil due to the rectification, and the rotation speed of the DC machine is suppressed. In particular, when the effective magnetic flux of the main magnetic pole is increased by the auxiliary magnetic pole, the output is increased, but the rotational speed is suppressed due to the influence of the reactance voltage.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a DC machine capable of achieving both an increase in output and an increase in rotation speed.

[0005]

The DC machine of the present invention employs the following technical means. [Means of Claim 1] A DC machine comprises: (a) an armature provided with an armature coil that generates a magnetic flux when energized; (b) a commutator that energizes the armature coil; and (c) this commutation. A brush that contacts the armature and energizes the armature coil, (d)
A yoke for accommodating the armature; (e) a plurality of main magnetic poles arranged inside the yoke to generate a magnetic flux that acts on the magnetic flux generated by the armature coil;
A first auxiliary magnetic pole that is disposed between the poles of two adjacent main magnetic poles, has a magnetic pole direction toward the two main magnetic poles, and has the same polarity as opposed to the polarities of the side surfaces of the two main magnetic poles; (G) A second auxiliary that is arranged at an intermediate position between the poles where the first auxiliary magnetic pole is not present, has a magnetic pole direction in a direction from the yoke to the armature, and cancels the magnetomotive force of the armature coil at the arranged position. And a magnetic pole.

[Means for Claim 2] In the DC machine according to claim 1, the second auxiliary magnetic pole is a permanent magnet.

[Means for Claim 3] In the DC machine according to claim 1, the second auxiliary magnetic pole is an auxiliary pole core provided at an intermediate position between the poles, and the second auxiliary pole is wound around the auxiliary pole core, The exciting magnet is composed of a commutating pole coil in which a current supplied to a child coil flows in series.

[0008]

Action of the Invention and Effect of the Invention

[Operation and Effect of Claim 1] The first auxiliary magnetic pole arranged between the poles of the two adjacent main magnetic poles has the same magnetic pole on the side surface of the adjacent main magnetic pole. The leakage flux between them is suppressed, and the effective flux from the main pole to the armature coil via the gap is increased. The second auxiliary magnetic pole arranged on the magnetic pole on which the first auxiliary magnetic pole is not arranged cancels the magnetomotive force of the rotating armature coil, cancels the reactance voltage generated in the armature coil by rectification, and
It also cancels the armature reaction near the auxiliary pole.

The output of the DC machine can be increased by increasing the effective magnetic flux of the main magnetic pole by the first auxiliary magnetic pole. Further, by canceling the reactance voltage due to the rectification by the second auxiliary magnetic pole, even if the rotation of the armature rises, the rectification state between the brush and the commutator becomes good, and the voltage generated between the brush and the commutator. The descent can be kept low. In this way, by suppressing the voltage drop between the brush and the commutator, it is possible to prevent the rotation speed of the armature from decreasing. Furthermore, since the armature reaction can also be suppressed by the second auxiliary magnetic pole, the decrease in the magnetic flux of the main magnetic pole due to the armature reaction can be suppressed, and the output of the DC machine can be increased also from this result.

That is, by increasing the effective magnetic flux of the main magnetic pole by the first auxiliary magnetic pole and suppressing the loss due to rectification by the second auxiliary magnetic pole, it is possible to improve the output and suppress the decrease in the rotation speed.

[Operation and Effect of Claim 2] By providing the second auxiliary magnetic pole with a permanent magnet, the configuration of the DC machine can be simplified and a high-performance DC machine can be provided at a low cost.

[Operation and effect of claim 3] By changing the number of turns of the auxiliary pole coil of the second auxiliary pole by using the second auxiliary pole as an exciting magnet in series with the armature coil, the second auxiliary pole can be changed. The action of the magnetic poles can be changed. Therefore, in addition to the combination of the first auxiliary magnetic pole and the second auxiliary magnetic pole,
Further, since the number of turns of the interpolator coil can be selected, the degree of freedom in designing the DC machine can be increased, and the performance of the DC machine can be easily improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a DC machine according to the present invention will be described with reference to the drawings based on an embodiment in which a starter for starting an engine is used. [Structure of First Embodiment] FIGS. 1 and 2 show a first embodiment. FIG. 1 is a schematic sectional view of a DC machine, and FIG. 2 is a schematic structure diagram of a starter. The starter 1 includes a pinion 3 that is arranged to be meshable with a ring gear 2 that is connected to a crankshaft of an engine, a DC machine 4 that rotationally drives the pinion 3,
The deceleration mechanism 5 that decelerates the rotation of the DC machine 4 and applies it to the pinion 3 and the one-way clutch 6 that shuts off the driving force when the pinion 3 is driven by the ring gear 2.

The starter 1 also generates a displacement force for engaging the pinion 3 with the ring gear 2 of the engine, and also has a battery 32 for the positive electrode brush 21 (described later).
A magnet switch 7 for energizing to is provided. The displacement force generated by this magnet switch 7 is
It is transmitted to the pinion 3 by the displacement force transmission means 8 and the pinion 3 is displaced to the ring gear 2 side.

The DC machine 4 is provided in a cylindrical yoke 13, and is provided with an armature 14 rotatably provided in the yoke 13 and a field pole 15 fixed inside the yoke 13.

The armature 14 includes a rotary shaft 16 rotatably supported in the yoke 13, an armature core 17 fixed to the rotary shaft 16, an armature coil 18,
The positive electrode brush 21 and the negative electrode brush 22 are composed of a commutator 23 in sliding contact with each other. Further, the negative electrode brush 22 is grounded to the vehicle body via the housing of the starter 1.

The field magnetic poles 15 are a plurality (six in this embodiment) of main magnetic poles 24a to 24f, which generate magnetic flux acting on the magnetic flux generated by the armature coil 18, and the main magnetic poles 24a to 24f.
A plurality of (three in the present embodiment) first auxiliary magnetic poles 25a to 25c arranged between the poles 24f to increase the effective magnetic flux of the main magnetic poles 24a to 24f, and the first auxiliary magnetic poles 25a to 25c.
A plurality of (three in the present embodiment) second auxiliary magnetic poles 26 are provided between the poles where 25c is not provided to improve the rectifying action.
a to 26c.

The main magnetic poles 24a to 24f are permanent magnets having a magnetic pole direction from the yoke 13 to the armature 14,
As shown in FIG. 1, the polarity on the armature 14 side is spatially 6
They are arranged at equal intervals such that the N poles and the S poles are alternately located so that they are shifted by 0 °. That is, if the polarity of the main pole 24a on the armature 14 side is the S pole, the main poles 24c, 2
4e has an S pole on the armature 14 side, and the main magnetic poles 24b, 2
The polarities on the armature 14 side of 4d and 24f are N poles.

The first auxiliary magnetic poles 25a to 25c are composed of two adjacent main magnetic poles (24a and 24b, 24c and 24d, 24).
e and 24f), the permanent magnets are arranged between the two poles, have a magnetic pole direction toward the main magnetic poles on both sides, and have the same polarity with respect to the polarities of the side faces of the adjacent main magnetic poles. Among them, they are arranged between three poles at equal intervals. That is, the main magnetic pole 24a is provided between the main magnetic pole 24a and the main magnetic pole 24b.
When the first auxiliary magnetic pole 25a is arranged so that the S pole faces toward the side and the N pole faces toward the main pole 24b, the main magnetic pole 24c and the main magnetic pole 24 are arranged.
During d, the S pole faces the main magnetic pole 24c side, and the main magnetic pole 24d
The first auxiliary magnetic pole 25b facing the N pole is disposed on the side, and the main magnetic pole 24e is provided between the main magnetic pole 24e and the main magnetic pole 24f.
The first auxiliary magnetic pole 25c is arranged so that the S pole faces toward the side and the N pole faces toward the main pole 24f.

The second auxiliary magnetic poles 26a to 26c are arranged at an intermediate position between the poles where the first auxiliary magnetic poles 25a to 25c are not arranged, specifically, at the geometrical neutral axis of the magnetic flux of the main magnetic pole, and the yoke is formed. 13 is a permanent magnet that has a magnetic pole direction in a direction from the armature 14 toward the armature 14 and cancels the magnetomotive force of the armature coil 18 at the arrangement position. If the rotation direction of the armature 14 is the arrow direction in FIG. The side magnetic pole is arranged so as to be a magnetic pole different from the magnetic pole of the main magnetic pole which is advanced by one in the rotational direction. That is, the main magnetic pole 24b and the main magnetic pole 24c
A second auxiliary magnetic pole 26a disposed between the main magnetic pole 24d and the main magnetic pole 24e, and a second auxiliary magnetic pole 26c disposed between the main magnetic pole 24f and the main magnetic pole 24a. The polarities of the respective armatures 14 are such that the N poles are opposite to the polarities (S poles) of the main magnetic poles 24c, 24e, 24a that are advanced by one in the rotation direction.

The speed reducing mechanism 5 uses a plurality of gears to reduce the rotational output generated by the DC machine 4 to improve the torque. In this embodiment, a planetary gear mechanism that can downsize the speed reducing mechanism 5 is adopted. are doing.

[Operation of First Embodiment] Next, the operation of the above embodiment will be described. When the starter switch 31 is turned on,
An exciting coil (not shown) in the magnet switch 7 is energized to displace the plunger shaft 34, and the battery 3
The electric power of 2 is supplied to the positive electrode brush 21, and the DC machine 4 rotates. At the same time, the displacement force of the plunger shaft 34 is transmitted to the pinion 3 via the displacement force transmission means 8, and the pinion 3 meshes with the ring gear 2. The rotation of the DC machine 4 is reduced by the reduction mechanism 5 and transmitted to the pinion 3, and the pinion 3 cranks the crankshaft of the engine via the ring gear 2.

When the engine starts, the starter switch 31
When is turned off, the exciting coil is also turned off and the plunger shaft 34 is returned to its original position. Then, the displacement force transmitting means 8 loses the action of pushing the pinion 3 toward the ring gear 2 side, and the pinion 3 separates from the ring gear 2. At the same time, the conduction between the battery 32 and the positive electrode brush 21 is also cut off,
The energization of the DC machine 4 is stopped. As a result, the DC machine 4 stops and the rotation of the pinion 3 also stops. That is, the starter 1 stops.

[Effects of First Embodiment] In the DC machine 4 used in the starter 1 of this embodiment, the three first auxiliary magnetic poles 25a to 25c arranged between the poles are the main magnetic pole 24a and the main magnetic pole 24b.
Between the main magnetic pole 24c and the main magnetic pole 24d, between the main magnetic pole 24e.
The leakage flux between the main magnetic pole 24f and the main magnetic pole 24f can be reduced to almost zero, and the effective magnetic flux from the main magnetic poles 24a to 24f to the armature coil 18 via the gap can be increased to the maximum. As a result, the output of the DC machine 4 can be increased.

Further, the three second auxiliary magnetic poles 26a to 26c arranged between the poles cancel the reactance voltage generated in the armature coil 18 which is short-circuited between the positive electrode brush 21 and the negative electrode brush 22 and which adversely affects the rectification. You can Therefore, even if the rotation of the armature 14 rises, the positive electrode brush 21 and the negative electrode brush 22, and the armature coil 18
The voltage drop generated between the commutator 23 and the commutator 23 can be suppressed low. In this way, by suppressing the voltage drop between the positive and negative electrode brushes 21 and 22 and the commutator 23, it is possible to prevent the rotation speed of the armature 14 from decreasing.

Further, since the armature reaction can be suppressed by the second auxiliary magnetic poles 26a to 26c, it is possible to suppress the magnetic flux reduction of the main magnetic poles 24a to 24f due to the armature reaction and increase the output of the DC machine 4. You can

The following Table 1 shows a first comparative DC machine which does not use the first auxiliary magnetic pole and the second auxiliary magnetic pole, and a second comparative DC machine in which only the first auxiliary magnetic pole is arranged between all (six) poles. And the experimental results of measuring the output, torque, and rotation speed using the DC machine 4 of the present embodiment.

[Table 1]

As can be seen from the results of this experiment, the DC machine 4 of this embodiment has a large torque increase rate of 10% and a rotational speed decrease rate of 3.5% as compared with the first comparative DC machine. , The rotation speed reduction rate is small. Further, the torque reduction rate is 1.3% and the rotation speed increase rate is 3.8 with respect to the second comparative DC machine.
%, The torque decrease can be suppressed and the rotation speed can be increased. That is, the first auxiliary magnetic poles 25a to 25c and the second auxiliary magnetic pole 26a.
26c, it is possible to suppress the increase of the maximum output and the decrease of the rotation speed without changing the outer dimensions of the DC machine 4.

[Second Embodiment] FIG. 3 is a schematic sectional view of a DC machine showing a second embodiment. In this embodiment, the second auxiliary magnetic pole 2
The permanent magnets 6a to 26c are changed from the permanent magnets of the first embodiment to exciting magnets. The auxiliary magnets 6a to 26c are provided at intermediate positions between the poles, and the auxiliary pole coils 51 extend from the yoke 13 toward the armature 14 around the auxiliary pole coil. The coil 52 is wound a predetermined number of times, and the auxiliary pole coil 52 is provided so that the current supplied to the armature coil 18 flows in series.

Thus, the second auxiliary magnetic poles 26a to 26c are
By changing the number of turns of the auxiliary pole coil 52, the magnetic force of the second auxiliary magnetic poles 26a to 26c can be changed. Therefore, the first auxiliary magnetic pole 25
In addition to the combination of a to 25c and the second auxiliary magnetic poles 26a to 26c, the number of turns of the auxiliary pole coil 52 can be further selected, so that the degree of freedom in designing the DC machine 4 can be increased and the DC machine 4
The performance of can be easily improved.

[Modification] In the above embodiment, an example is shown in which the first auxiliary magnetic pole and the second auxiliary magnetic pole are provided at the same ratio and arranged at equal intervals. The number and arrangement position of the second auxiliary magnetic poles that act to improve the rectification may be determined depending on the magnetic flux action of the child coil, the magnitude of the armature reaction, the rotation speed of the armature, the magnetic force of the second auxiliary magnetic pole, and the like. That is, the ratio of the first auxiliary magnetic pole to the second auxiliary magnetic pole and the mounting position may be changed according to the DC machine used.

Although an example in which the main magnetic pole is a permanent magnet is shown, it may be an exciting magnet. An example in which the first auxiliary magnetic pole is a permanent magnet is shown, but an exciting magnet may be used. Although an example in which the coil end of the armature coil is used as a commutator has been shown, a commutator may be provided separately from the armature coil to electrically connect the armature coil and the commutator.

The starter with a reduction mechanism shown in the above embodiment is an example, and the present invention may be applied to a starter with a reduction mechanism adopting another structure. Further, although an example in which the DC machine of the present invention is applied to a starter is shown, it is also applicable to other DC machines that rotate at high speed.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a DC machine (first embodiment).

FIG. 2 is a schematic configuration diagram of a starter (first embodiment).

FIG. 3 is a schematic sectional view of a DC machine (second embodiment).

[Explanation of symbols]

 1 Starter 4 DC machine 5 Reduction mechanism 13 Yoke 14 Armature 18 Armature coil 21 Positive brush 22 Negative brush 23 Commutator 24a-24f Main magnetic pole 25a-25c 1st auxiliary magnetic pole 26a-26c 2nd auxiliary magnetic pole

Claims (3)

[Claims] 1. An armature provided with an armature coil for generating a magnetic flux upon receiving an electric current, (b) a commutator energizing the armature coil, and (c) a commutator in contact with the commutator. A brush that energizes the armature coil; (d) a yoke that houses the armature; and (e) a plurality of magnets that are arranged inside the yoke and that generate a magnetic flux that acts on the magnetic flux generated by the armature coil. The main magnetic pole, and (f) is placed between two adjacent main magnetic poles.
A first auxiliary magnetic pole having a magnetic pole direction toward the two main magnetic poles and having the same polarity opposite to the polarities of the side surfaces of the two main magnetic poles; A DC machine having a second auxiliary magnetic pole arranged at a position, having a magnetic pole direction in a direction from the yoke toward the armature, and canceling a magnetomotive force of the armature coil at the arranged position. 2. The DC machine according to claim 1, wherein the second auxiliary magnetic pole is a permanent magnet. 3. The DC machine according to claim 1, wherein the second auxiliary magnetic pole is supplied to the armature coil by winding the auxiliary pole core provided at an intermediate position between the poles and the auxiliary pole core. A direct-current machine characterized in that it is an exciting magnet consisting of a supplemental-pole coil through which a current flowing in series flows.