JP2003230242A - Dc motor and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a DC motor which is excellent in the mass balance of a coil and its manufacturing method. <P>SOLUTION: The DC motor is equipped with an iron core which has n (n≥5) pieces of slots at the periphery and n pieces of coils which are made by winding lead wires in a pair of slots out of n pieces of slots. N pieces of coils are each stored in the shape of two-layer winding consisting of an inner peripheral layer and an outer peripheral layer in each slot. N-2 pieces of coils out of n pieces of coils are outer-inner coils 32c which form the outer peripheral layer of one hand out of, for example, a pair of slots 22a and 30a and form the inner peripheral layer of the other hand. One piece of coil is an inner-inner coil 1c which forms the inner peripheral layers of both of a pair of slots 5a and 13a. One piece of coil is an outer-outer coil 33c which forms the outer peripheral layers of both of a pair of slots 30a and 5a. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC motor incorporated in, for example, a forklift or a blower, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a conductor forming a coil in a DC motor is wound and housed in an iron core slot by wave winding or lap winding. FIG. 6 shows an end view of the iron core during winding of the conductive wire. The iron core 100 has a columnar shape. A round rod-shaped rotating shaft 102 penetrates through the center of the iron core 100. There are a total of 3 groove-shaped slots on the outer peripheral surface of the iron core 100.
Three are arranged.

The coils are arranged in the slots in the following manner, for example, by using a double winding machine in which the coils are simultaneously arranged in two pairs of slots. First, connect one end of the lead wire to a commutator piece (not shown). Then, the lead wire is passed through the slot 101. Then, from the slot 101 to the slot 102 arranged at the slot pitch = 9 in the clockwise direction,
Pass this lead wire. Then, a conductive wire is wound between the slot 101 and the slot 102. Then, the other end of the conducting wire is connected to a predetermined commutator piece. In this way, the coil 109
To place. At this time, at the same time, the coil 110 is arranged between the slots 103 and 104 in the same procedure in parallel with the arrangement of the coil 109.

Then, the coil 111 is arranged by winding the conductive wire forming the coil 109 between the slots 105 and 106. Further, in parallel with the arrangement of the coil 111, the coil 112 is arranged between the slot 107 and the slot 108 by the same procedure. In this way, the coil is gradually wound in the counterclockwise direction indicated by the arrow in the figure. Then, in each of the slots, a total of two layers of coils including an inner layer and an outer layer are arranged at an inner peripheral side position 113 and an outer peripheral side position 114.

[0005]

However, according to the above-mentioned conventional winding method, the mass difference between the coils becomes large. That is, when the coil is advanced as described above,
The first to 16th coils are arranged at the inner peripheral side position 113 of each slot. Here, two slots forming a pair are required to arrange one coil.
Therefore, the 1st to 16th coils make 3
The positions 113 on the inner peripheral side of the two slots are filled.
Therefore, the 17th coil is arranged at the inner peripheral side position 113 of one slot and the outer peripheral side position 114 of the other slot in the two slots forming a pair. The eighteenth to thirty-third coils are arranged at the outer peripheral side positions 114 of the two slots forming a pair.

Here, the coils disposed between the inner peripheral side positions 113, that is, the inner-inner coil and the outer peripheral side position 114.
Although the coils arranged between each other, that is, the outer-outer coil, have the same number of turns of the conductive wire forming the coil, but have different winding lengths. With the coils arranged at the inner peripheral side positions 113 and the coils arranged at the outer peripheral side positions 114,
The coil resistance and inductance are also different. For this reason, rectifying sparks are easily generated between the brushes that are in sliding contact with the commutator pieces for supplying power, and the brush wear is accelerated. Therefore, the life of the brush is shortened and the frequency of maintenance of the DC motor is increased. Further, the inner-inner coil and the outer-outer coil have different coil masses. Therefore, the iron core 100 wound with the coils having different masses has poor mass balance. Therefore, the rotation of the iron core 100 may be unbalanced when the DC motor is driven. Iron core 100
The unbalanced rotation causes a loud noise during driving.

The DC motor and its manufacturing method of the present invention have been completed in view of the above problems. Therefore, it is an object of the present invention to provide a DC motor having a good coil resistance balance and a simple manufacturing method thereof.

[0008]

(1) In order to solve the above problems, the DC motor of the present invention has n (n ≧ 5) on the outer peripheral surface.
An iron core having a number of slots, and n coils formed by winding a conductive wire around a pair of slots among the n number of slots, the n number of coils each including an inner coil in each slot. A DC motor housed in a two-layer winding structure including a peripheral layer and an outer peripheral layer, wherein n-2 of n coils
The individual coils are outer-inner coils that form one outer peripheral layer of the pair of slots and form the other inner peripheral layer,
One coil of the remaining two coils is an inner-inner coil that forms the inner peripheral layers of both of the pair of slots, and the last one coil forms the outer peripheral layer of both of the pair of slots. It is characterized by being an outer-outer coil.

The DC motor of the present invention comprises n coils. Of these n coils, n-2 coils are outside-
It is an inner coil. Further, one coil is an inner-inner coil. Also, one coil is an outer-outer coil. If the number of turns of the conductor wire of these coils is the same, the winding length is proportional to the coil mass. Therefore, the coil having the largest coil mass is the outer-outer coil forming the outer peripheral layers of the pair of slots. The second largest coil mass is
The outer-inner coil forms one outer peripheral layer and the other inner peripheral layer of the pair of slots. Further, the coil having the smallest coil mass is the inner-inner coil forming the inner peripheral layers of the pair of slots.

According to the DC motor of the present invention, n-2 coils among the n coils are outer-inner coils. That is, most of all the coils are outer-inner coils having the same mass. Therefore, the DC motor of the present invention has a good coil resistance balance. Therefore, in the DC motor of the present invention, the generation of commutation sparks due to the coil resistance difference is suppressed, and the brush is less likely to wear. Further, since the mass balance of each coil is good, the driving noise of the DC motor of the present invention is small.

(2) Preferably, the n coils are inner-
In order to reduce the mass difference between the inner coil and the outer-outer coil,
It is preferable that the number of windings of the conductor wire is adjusted. That is, in this structure, the number of turns of the conductor wire is increased or decreased by the coil. When the number of turns of the conductive wire is the same, the winding lengths of the inner-inner coil and the outer-outer coil are significantly different. For this reason,
The inner coil and the outer-outer coil differ greatly in mass. Therefore, the mass difference between the inner-inner coil and the outer-outer coil is
This will be one of the causes of upsetting the resistance balance of the coil. In this configuration, the difference in mass between the inner-inner coil and the outer-outer coil is corrected by increasing or decreasing the number of turns of the conductor wire of each coil. Therefore, the DC motor having this configuration has a better coil resistance balance.

(3) The DC motor of the present invention is suitable for use in a power steering device to assist the steering force. For example, a DC motor used in a power steering device such as an electric forklift truck is required to have low maintenance frequency. In this respect, the DC motor of the present invention has a good coil resistance balance.
Therefore, the DC motor of the present invention requires less frequent replacement of consumable brushes. Therefore, the DC motor of the present invention is suitable for use in a power steering device.

(4) In order to solve the above problems, the method for manufacturing a DC motor according to the present invention uses n (n ≧ 5) on the outer peripheral surface.
An iron core having a number of slots, and n coils formed by winding a conductive wire around a pair of slots among the n number of slots, the n number of coils each including an inner coil in each slot. A method for manufacturing a direct current motor, which is housed in a two-layer winding shape composed of a peripheral layer and an outer peripheral layer, wherein a first coil of n coils is arranged in a pair of slots, The first coil arranging step of forming each inner peripheral layer, the slot in which the inner peripheral layer is formed, and the slot in which the coil is not yet arranged are paired with k (k
= 2 to n-1) th coil is arranged,
The k-th coil arranging step of sequentially forming the outer peripheral layer and the inner peripheral layer in the pair of slots, the slot in which the inner peripheral layer is formed by the (n-1) th coil, and the inner peripheral layer by the first coil. A n-th coil arrangement step of forming an outer peripheral layer in each of the pair of slots by arranging an n-th coil in a pair with a slot in which the outer peripheral layer is not yet formed among the pair of formed slots; It is characterized by comprising.

The DC motor manufacturing method of the present invention includes a first coil arranging step, a kth coil arranging step, and an nth coil arranging step. In the first coil arranging step, the inner peripheral layer is formed in each of the pair of slots. In other words, the inner-inner coil is arranged. The inner-inner coil is the first coil. In the k-th coil arrangement step, the outer peripheral layer is formed on one of the pair of slots and the inner peripheral layer is formed on the other. In other words, the outer-inner coil is arranged. Then, the outer-inner coils are arranged in order from the second coil to the (n-1) th coil. In the n-th coil arranging step, the outer peripheral layer is formed in each of the pair of slots. The k th
At the time when the coil arranging step is completed, the coils are not yet stored in the n slots because the outer peripheral layer position is one of the pair of slots having the (n-1) th coil,
Only the outer peripheral layer position of one of the pair of slots in which the first coil is located. In this step, a conductive wire is wound around the remaining positions of the outer peripheral layers to form an outer peripheral layer in each slot. In other words, the outer-outer coil is arranged.

According to the method of manufacturing a DC motor of the present invention,
A DC motor having a coil with excellent resistance balance can be easily manufactured. In other words, the winding machine that has been conventionally used can be used as it is for manufacturing without any improvement. Therefore, according to the method of manufacturing a DC motor of the present invention, it is possible to manufacture a DC motor having a coil excellent in resistance balance with relatively simple work and at low cost.

(5) Preferably, in the manufacturing method of the above (4), in order to reduce the mass difference between the first coil and the nth coil, the n-3rd to nth coils are:
It is preferable that the number of turns of the conductive wire is smaller than that of the first to n-4th coils.

That is, this configuration reduces the number of turns of the conductor wire of the coils arranged at the n-3rd and subsequent positions. The first coil is the inner-inner coil. The nth coil is outside-
It is an outer coil. Therefore, there is a possibility that the resistance balance of the coils may deteriorate due to the mass difference between these two coils.

In this configuration, the number of turns of the conductive wire of the nth to nth coils is reduced. According to this configuration, a DC motor having a coil having a better resistance balance can be manufactured by a relatively simple method of reducing the number of windings of the conductive wire.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a DC motor and a manufacturing method thereof according to the present invention will be described below. The DC motor of this embodiment is incorporated in a power steering device of an electric forklift truck.

First, the structure of the DC motor of this embodiment will be described. FIG. 1 shows an axial sectional view of a DC motor of this embodiment. The yoke 2 is made of metal and has a cylindrical shape. The yoke 2 forms the outer shell of the DC motor 1. An iron core 3, a commutator 4, a magnetic pole 5, a front bearing 60, a rear bearing 61, a rotary shaft 7, and a coil (not shown) are arranged on the inner peripheral side of the yoke 2.

The front bearing 60 is fixed to the inner surface of the front end wall of the yoke 2. On the other hand, the rear bearing 61 is fixed to the inner surface of the rear end wall of the yoke 2. The rotating shaft 7 is made of metal and has a round bar shape. The rotary shaft 7 is a front bearing 60.
And a rear bearing 61. Rotating shaft 7
Has a front end protruding from the front end wall of the yoke 2.

The iron core 3 has a cylindrical shape. Iron core 3
Is formed by laminating a large number of thin iron plates in the axial direction. The rotary shaft 7 penetrates through the center of the iron core 3.
The iron core 3 is fixed to the rotary shaft 7. A groove-shaped slot 30 is formed on the outer peripheral surface of the iron core 3. Slot 3
0 extends in the axial direction of the iron core 3. Again slot 30
Are arranged in a total of 33 rows in the circumferential direction of the iron core 3.

The commutator 4 comprises a base 40 and a commutator piece 41. The base 40 is made of insulating resin and has a cylindrical shape. The base body 40 is arranged coaxially in front of the iron core 3. The commutator piece 41 is made of copper and has a strip shape. The commutator piece 41 has a brush sliding contact portion 42 and a hook 43. The brush sliding contact portion 42 is arranged on the outer peripheral surface of the base body 40. The hook 43 has a brush sliding contact portion 42.
It is arranged so as to extend radially from the rear end in the radial direction. The coil is formed by a conductor wire connected to the hook 43 and wound in the slot 30. The coil will be described later.

The magnetic pole 5 is made of a permanent magnet and has an arc plate shape. The magnetic pole 5 is fixed to the inner peripheral surface of the yoke 2. The magnetic pole 5 is arranged at a predetermined distance from the outer peripheral side of the iron core 3. The magnetic poles 5 are arranged in a total of four poles in a circumferentially spaced manner.

Next, a method of manufacturing the DC motor of this embodiment will be described. The manufacturing method of the DC motor includes a first coil arranging step, a kth coil arranging step, and a 33rd coil arranging step. In addition, before the first coil placement step,
The rotating shaft 7, the iron core 3, and the commutator 4 have already been assembled.

In the first coil arrangement step, the first coil is arranged in the pair of slots to form the inner peripheral layer in each of the pair of slots. Fig. 2 shows the specifications of the winding of the conductor. The slots and the commutator pieces that are aligned in the axial direction in FIG. 1 are indicated by the same numbers in FIG. Further, FIG. 3 shows a rear end view of the iron core on which the first coil is arranged. In this step, first, the assembly of the rotating shaft, the iron core and the commutator is set in the single winding machine. At this time, the former 8 which winds the conductive wire and supplies it to the slot is arranged on the outer peripheral side from the slot 5a to the slot 13a. That is, the slot pitch is set to 9.
In this step, next, one end of the conductor wire is connected to the hook of the commutator piece 1b. Then, the conductor is connected to the slot 5 by the former 8.
The first coil 1c is arranged by winding at a position on the inner peripheral side of a and a position on the inner peripheral side of the slot 13a. At this time, the inner peripheral layer 5d is formed in the slot 5a. In addition, the inner peripheral layer 13d is also formed in the slot 13a. That is, the first coil 1c is an inner-inner coil. Then, the other end of the wire is hooked on the hook of the commutator piece 17b.

In the k-th coil arranging step, from the second to 32
By sequentially arranging the coils up to the second in a pair of slots, an inner peripheral layer and an outer peripheral layer are sequentially formed in each slot. FIG. 4 shows a rear end view of the iron core in which the first coil and the second coil are arranged. In this step, first, the assembly of the rotating shaft, the iron core and the commutator is rotated counterclockwise about the rotating shaft as indicated by the arrow in the figure. Then, the former 8 is arranged on the outer peripheral side from the slot 13a to the slot 21a. In this step, next, the conducting wire hooked on the hook of the commutator piece 17b is bypassed and hooked on the hook of the commutator piece 9b. Then, the conductor 8 is wound around the outer peripheral side position of the slot 13a and the inner peripheral side position of the slot 21a by the former 8 to arrange the second coil 2c. At this time, the outer peripheral layer 13e is formed in the slot 13a. In addition, the inner peripheral layer 21 is provided in the slot 21a.
d is formed. That is, the second coil 2c is an outer-inner coil. Then, the other end of the wire is hooked on the hook of the commutator piece 25b.

By repeating this operation in order, the 3rd to 32nd coils are similarly arranged in the slots. That is, like the second coil 2c, the third to 32nd coils are also outer-inner coils. However, the number of turns of the conductor wire of the 30th to 32nd coils is 1
The number is smaller than the number of turns of the conducting wire of the 29th to 29th coils.

In the 33rd coil arranging step, the 33rd coil is arranged in a pair of slots to form an outer peripheral layer in each of the pair of slots. FIG. 5 shows a rear end view of the iron core in which the 32nd coil 32c, the 33rd coil 33c and the 1st coil 1c are arranged. It should be noted that the numbers 2 to 31 are omitted. In this step, first, the assembly of the rotating shaft, the iron core and the commutator is rotated counterclockwise about the rotating shaft as indicated by the arrow in the figure. Then, the former 8 is arranged on the outer peripheral side from the slot 30a to the slot 5a. In this step, next, the conductor wire connected to the hook of the commutator piece 1b is bypassed and the commutator piece 26b is bypassed.
Connect to the hook. Then, the conductor 8 is wound around the outer peripheral side position of the slot 30a and the outer peripheral side position of the slot 5a by the former 8, and the 33rd coil 33c is arranged. However, the number of windings of the conductor wire of the 33rd coil 33c is made smaller than the number of windings of the conductor wire of the 1st to 29th coils, like the number of turns of the conductor wire of the 30th to 32nd coils. An outer peripheral layer 30e is formed in the slot 30a. In addition, an outer peripheral layer 5e is formed in the slot 5a. That is, the 33rd coil 33c is an outer-outer coil. Then, the other end of the conductor wire is connected to the hook of the commutator piece 9b.

After that, the iron core in which a total of 33 coils are arranged, the commutator and the rotary shaft are housed and arranged on the inner peripheral side of the yoke to which the bearing is fixed in advance. In this way, the DC motor of this embodiment is manufactured.

Of the 33 coils of the DC motor of this embodiment, a total of 31 coils from the 2nd coil to the 32nd coil are outer-inner coils. Also, the first coil is inside-
Although the inner coil and the 33rd coil are outer-outer coils, the 30th to 33rd coils have the number of windings of the conductor wire reduced as compared with the 1st to 29th coils.
Therefore, the resistance balance of the coil is excellent.

The embodiments of the DC motor and the manufacturing method thereof according to the present invention have been described above. However, the embodiment is not particularly limited to the above embodiment. The number of slots, the number of slot pitches, the number of commutator pieces, and the number of hook pitches are not particularly limited. For example, in the case of a motor having four magnetic poles, the number of slots may be n = 4m + 1 (m is a natural number). Although the open type slots are arranged in the present embodiment, semi-closed type and closed type slots may be arranged. Also, the shape of the commutator is not particularly limited. For example, a commutator having a shape in which commutator pieces are radially arranged with respect to the rotating shaft may be used.

[0033]

According to the present invention, it is possible to provide a DC motor having a good coil resistance balance and a simple manufacturing method thereof.

[Brief description of drawings]

FIG. 1 is an axial sectional view of a DC motor of this embodiment.

FIG. 2 is a winding specification diagram of a lead wire of the DC motor of the present embodiment.

FIG. 3 is a rear end view of the iron core on which the first coil is arranged.

FIG. 4 is a rear end view of an iron core on which a first coil and a second coil are arranged.

FIG. 5 is a rear end view of an iron core on which a No. 32 coil, a No. 33 coil and a No. 1 coil are arranged.

FIG. 6 is an end view of an iron core during a conventional coil arrangement.

[Explanation of symbols]

1: DC motor, 2: Yoke, 3: Iron core, 30: Slot, 4: Commutator, 40: Base, 41: Commutator piece, 42:
Brush sliding contact portion, 43: hook, 5: magnetic pole, 60: front bearing, 61: rear bearing, 7: rotating shaft, 8: former,
1a to 33a: slots, 1b to 33b: commutator pieces, 1
c-33c: coil, 1d-33d: inner peripheral layer, 1e-3
3e: outer peripheral layer.

Claims (5)

[Claims] 1. An iron core having n (n ≧ 5) slots on the outer peripheral surface, and n coils formed by winding a conductor wire around a pair of slots of the n slots. A direct current motor in which the n coils are housed in each slot in a two-layer winding structure including an inner peripheral layer and an outer peripheral layer, and n-2 of the n coils are provided. Is an outer-inner coil that forms one outer peripheral layer and the other inner peripheral layer of the pair of slots, and one of the remaining two coils is one of the pair of slots. A direct-current motor, which is an inner-inner coil forming inner layers of both slots, and a final coil is an outer-outer coil forming outer layers of both of the slots. 2. The DC motor according to claim 1, wherein the n coils have the number of windings of the conductor wire adjusted in order to reduce a mass difference between the inner-inner coil and the outer-outer coil. . 3. The DC motor according to claim 1, which is used for assisting a steering force in a power steering device. 4. An iron core having n (n ≧ 5) slots on the outer peripheral surface, and n coils formed by winding a conductor wire around a pair of slots of the n slots. A method of manufacturing a DC motor, wherein the n coils are housed in each slot in a two-layer winding structure including an inner peripheral layer and an outer peripheral layer, wherein 1 of the n coils is provided. A first coil placement step of forming an inner circumferential layer in each of the pair of slots by placing the second coil in the pair of slots, a slot in which the inner circumferential layer is formed, and a slot in which no coil is placed yet. And, paired with k (k = 2 to n−
1) The coil is placed by sequentially arranging an outer peripheral layer and an inner peripheral layer in the pair of slots, and an inner peripheral layer is formed by the (n-1) th coil. By arranging the n-th coil as a pair with a slot in which the outer peripheral layer is not yet formed among the pair of slots in which the inner peripheral layer is formed by the first coil. And a step of arranging nth coils for forming outer peripheral layers in the slots, respectively. 5. In order to reduce the mass difference between the first coil and the nth coil, the n-3rd to nth coils are more than the first to n-4th coils. The method of manufacturing a DC motor according to claim 4, wherein the number of windings of the conductive wire is small.