JP2002119031A - Motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor where a short-circuit current is restrained and a stable driving current can be supplied to a winding coil, in a motor with which the drive speed can be switched by selecting and connecting plural brushes. SOLUTION: A high potential side brush 7 for high speed is so constituted with low resistivity parts 7a, 7b of low resistivity sandwiching a high resistivity part 7c of high resistivity in the rotating direction of a commutator 2. The brush 7 is formed with the width of the low resistivity parts 7a, 7b being made slightly smaller than the width of a part between neighboring commutator segments 14. When a main switch 12 is connected, and moving terminals 10A, 11A of a first and a second change-over switches 10, 11 are connected with low speed time connection terminals 10L, 11L; the low resistivity part 7a of the side of a high potential side brush 6 for low speed is connected with the high potential side power source via a first resistor 8; and the low resistivity part 7b of the side of a low potential side brush 5 is connected with a low potential side power source via a second resistor 9. Accordingly, a prescribed voltage is supplied to a part between both of the low resistivity parts 7a, 7b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC motor whose drive speed can be switched.

[0002]

2. Description of the Related Art Conventionally, a DC motor capable of switching a driving speed is used in a vehicle wiper device or the like. As shown in the schematic diagram of FIG. 6, the motor 51 includes a commutator (commutator) 52, a winding coil 53, and a pair of magnets 54.
, A low-potential-side brush 55 and a low-speed high-potential-side brush 56
And a high-potential high-speed brush 57 and a changeover switch 58
And a main power switch 59.

The commutator 52 includes a plurality of commutator pieces (segments) 61 fixed to a rotating shaft 60 supported by a motor case (not shown) and arranged in a circular shape. The winding coils 53 are respectively connected between the adjacent commutator pieces 61 and wound around a core of an armature (not shown). Each of the pair of magnets 54 is formed in an arc shape, and is fixed to a motor case (not shown) so as to face each other around an armature (not shown) as shown by a two-dot chain line in FIG.

The low-potential-side brush 55 is disposed on a motor case (not shown) so as to contact the commutator piece 61 at a predetermined angular position where the magnet 54 is not disposed. The low-voltage high-potential-side brush 56 is located at an angular position where the magnet 54 is not arranged, and is arranged on a motor case (not shown) so as to contact the commutator piece 61 at a position of 180 degrees with respect to the low-potential-side brush 55. Has been established. The high-speed high-potential-side brush 57 is at an angular position where the magnet 54 is arranged, and at a position less than 180 degrees (about 120 degrees in FIG. 6) with respect to the low-potential-side brush 55, the commutator piece 61.
It is disposed on a motor case (not shown) so as to contact with the motor case.

The low-potential-side brush 55 is connected to a low-potential-side power supply (ground). High potential side brush 56 for low speed
Is connected to a low-speed connection terminal 58L of the changeover switch 58, and the high-speed high-potential-side brush 57 is connected to a high-speed connection terminal 58H of the changeover switch 58. The movable terminal 58A of the changeover switch 58 is connected to a high-potential power supply via a main power switch 59. And the changeover switch 5
8 is a low-speed connection terminal 58L or a high-speed connection terminal 58L.
H is switched to be connected to the high potential side power supply.

In the motor configured as described above, when the movable terminal 58A of the changeover switch 58 is connected to the low-speed connection terminal 58L and the low-speed high-potential brush 56 is connected to the high-potential power source, the drive current is reduced. Winding coil 53 from low potential high potential side brush 56 via commutator 52 (commutator piece 61)
Is supplied to the low-potential-side brush 55 and the armature and the rotating shaft 60 (not shown) rotate at a low speed.
When the movable terminal 58A of the changeover switch 58 is connected to the high-speed connection terminal 58H and the high-speed high-potential brush 57 is connected to the high-potential power source, the drive current is supplied from the high-speed high-potential brush 57 to the commutator. Since it is supplied to the winding coil 53 via the commutator piece 52 and flows to the low-potential side brush 55, the armature and the rotating shaft 60 (not shown) rotate at high speed.

[0007]

In the motor having the above structure, the high-speed high-potential side brush 5 not used during low-speed driving (not selected by the changeover switch 58) is used.
7 comes into sliding contact with the commutator piece 61. At the moment when the high-speed high-potential-side brush 57 contacts the adjacent commutator segments 61, there is a problem that the adjacent commutator segments 61 are short-circuited and a short-circuit current is generated. or,
At this time, the low-voltage high-potential side brush 56 is applied to the winding coil 53 connected between the adjacent commutator pieces 61 by the induced voltage generated in the winding coil 53 as shown in FIG.
There is a problem that a current Z, which is opposite to the current flowing direction (direction of the drive current) from the power supply to the low-potential side brush 55, flows instantaneously. These causes various causes such as generation of sparks and electric noise.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to suppress a short circuit current in a motor capable of switching a driving speed by selecting and connecting a plurality of brushes. Another object of the present invention is to provide a motor capable of supplying a stable drive current to a winding coil.

[0009]

According to a first aspect of the present invention, there is provided a commutator having a plurality of commutator pieces arranged in a circle, and a winding connected between adjacent ones of the commutator pieces. A coil, a low-potential-side brush arranged to be in contact with the commutator piece at a predetermined angular position, and connected to a low-potential-side power supply; and the commutator at a predetermined angular interval with respect to the low-potential-side brush. A motor comprising: a plurality of high-potential-side brushes arranged to be in contact with a piece; and a switch for selecting any one of the plurality of high-potential-side brushes and connecting to a high-potential-side power supply. At least one of the high-potential-side brushes is configured such that a low-resistivity portion having a low resistivity sandwiches a high-resistivity portion having a high resistivity in a rotation direction of the commutator, and The width in the rotation direction is equal to or less than the width of the gap between the adjacent commutator pieces. When the switch is switched to connect the predetermined high-potential-side brush and the high-potential-side power supply, a predetermined voltage is supplied between the low-resistivity portions. Voltage supply means.

According to a second aspect of the present invention, in the motor according to the first aspect, the predetermined voltage is set to be substantially the same as a voltage between the adjacent commutator pieces that are not short-circuited. According to a third aspect of the present invention, in the motor according to the first or second aspect, the voltage supply unit is switched such that the switch connects the predetermined high potential side brush and the high potential side power supply. When one of the low resistivity portions is connected to the predetermined high potential side brush via a first resistor, the other low resistivity portion is connected to the low potential side power supply via a second resistor. Connect to

[0011] The invention according to claim 4 is the invention according to claims 1 to 3.
The high-potential-side brush according to any one of claims 1 to 3, wherein the high-potential-side brush is arranged to be in contact with the commutator piece at a position spaced 180 degrees from the low-potential-side brush. And 180 with respect to the low potential side brush.
A high-potential high-side brush arranged so as to be in contact with the commutator segments at positions less than degrees apart, and the low-speed high-potential brush is driven at a low speed when the low-potential high-side brush is connected to the high-potential power supply. The high-speed driving is performed when the high-speed high-potential-side brush is connected to the high-potential-side power supply.

According to a fifth aspect of the present invention, in the motor according to the fourth aspect, the high potential side brush having the low resistivity portion and the high resistivity portion is the high potential high potential side brush, The voltage supply means, when the switch is switched to connect the low-potential high-potential-side brush and the high-potential-side power supply, between the two low resistivity portions of the high-potential high-potential-side brush, The predetermined voltage is supplied.

According to a sixth aspect of the present invention, there is provided a commutator having a plurality of commutator pieces arranged in a circle, a winding coil connected between adjacent ones of the commutator pieces, and a predetermined angular position. A low-potential-side brush connected to a low-potential-side power supply and arranged to be in contact with the commutator segment at a predetermined angular interval with respect to the low-potential-side brush. A motor comprising: a plurality of high-potential-side brushes arranged; and a switch that selects one of the plurality of high-potential-side brushes and switches to connect to a high-potential-side power supply, At least one of the side brushes has a low resistivity portion having a low resistivity sandwiching a high resistivity portion having a high resistivity in a rotation direction of the commutator, and a width of the low resistivity portion in the rotation direction is small. Formed to be less than the width of the gap between the adjacent commutator pieces When the switch is switched to connect the predetermined high-potential-side brush and the high-potential-side power supply, the low-resistivity portions of the other high-potential-side brushes Also do not connect.

(Operation) According to the first aspect of the present invention,
A drive speed is switched by selecting one of the plurality of high-potential-side brushes with a switch and connecting to the high-potential-side power supply. When the predetermined high-potential-side brush and the high-potential-side power supply are switched to be connected, a voltage supply means is provided between the two low-resistivity portions sandwiching the high-resistance portion of the unselected high-potential-side brush. Is supplied with a predetermined voltage.
Therefore, when a predetermined high-potential-side brush and the high-potential-side power supply are switched to be connected, a short-circuit current when an unselected high-potential-side brush contacts across adjacent commutator pieces is suppressed. can do. In addition, since the width of the low resistivity portion in the rotation direction is equal to or less than the width of the gap between the adjacent commutator pieces, the adjacent commutator pieces are electrically connected only through one of the low resistivity portions. There is no short circuit current. From these facts, it is possible to suppress a current (a current in a direction opposite to a drive current) based on an induced voltage generated in a winding coil connected between adjacent commutator pieces from flowing through the winding coil. Can be.

According to the second aspect of the present invention, when the high-potential-side brush not selected by the switch contacts across the adjacent commutator pieces, the voltage supply means is provided between the low-resistivity portions. Since a voltage that is set to be substantially the same as the voltage between adjacent commutator pieces that are not short-circuited is supplied, short-circuit current between adjacent commutator pieces is suppressed. This suppresses a current (a current in a direction opposite to the drive current) based on the induced voltage generated in the winding coil connected between the adjacent commutator pieces from flowing through the winding coil.

According to the third aspect of the present invention, when the predetermined high-potential-side brush is switched to be connected to the high-potential-side power supply, one of the low-resistivity portions is switched to the second low-resistance portion by the voltage supply means. By connecting to the predetermined high-potential-side brush via a first resistor, that is, a high-potential-side power supply, and connecting the other low-resistance portion to a low-potential-side power supply via a second resistor,
A predetermined voltage is supplied between the two low resistivity portions.

According to the fourth aspect of the present invention, the high-potential-side brush is disposed at a position 180 degrees apart from the low-potential-side brush so as to contact the commutator piece. A high-speed high-potential brush arranged to be in contact with the commutator strip at a position less than 180 degrees from the low-potential brush. When the low-potential high-potential-side brush is connected to the high-potential-side power supply, the low-speed driving is performed,
When the high-speed high-potential-side brush is connected to the high-potential-side power supply, high-speed driving is performed.

According to the fifth aspect of the present invention, when the high-potential-side brush for low-speed and the high-potential-side power supply are switched to be connected, the low-resistance portion of the high-potential-side brush for high-speed is connected. Is supplied with a predetermined voltage by voltage supply means. Therefore, the high-speed side brush for low speed is selected by the switch,
It is possible to suppress a short-circuit current when an unselected high-speed high-potential-side brush contacts across adjacent commutator segments. Thus, it is possible to suppress a current (a current in a direction opposite to the drive current) based on the induced voltage generated in the winding coil connected between the adjacent commutator pieces from flowing through the winding coil. .

According to the sixth aspect of the present invention, one of the plurality of high-potential-side brushes is selected by the switch and connected to the high-potential-side power supply, thereby switching the driving speed. When the predetermined high-potential-side brush and the high-potential-side power supply are switched to be connected, the two low-resistivity portions sandwiching the high-resistivity portions of the other unselected high-potential-side brushes, Also not connected. In addition, since the width of the low resistivity portion in the rotation direction is equal to or less than the width of the gap between the adjacent commutator pieces, the adjacent commutator pieces are electrically connected only through one of the low resistivity portions. There is no short circuit current. Therefore, the short-circuit current is suppressed, and the current based on the induced voltage generated in the winding coil connected between the adjacent commutator pieces (current in the direction opposite to the driving current) does not flow through the winding coil. Is suppressed.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) A first embodiment in which the present invention is embodied in a motor for a vehicle wiper device will be described below with reference to FIGS. FIG. 1 shows a schematic diagram of the motor 1. As shown in FIG. 1, the motor 1 includes a commutator (a commutator) 2, a winding coil 3, a pair of magnets 4, a low-potential-side brush 5, a low-potential-side high-potential brush 6, and a high-speed A potential side brush 7, first and second resistors 8, 9, first and second changeover switches 10, 11,
And a main power switch 12. In the present embodiment, the high potential side brush 6 for low speed and the high potential side brush 7 for high speed form a plurality of high potential side brushes. In the present embodiment, the first and second resistors 8 and 9 and the first and second resistors 8 and 9 are used.
The changeover switches 10 and 11 constitute voltage supply means.

The commutator 2 has a plurality of commutator pieces (segments) 14 fixed to a rotating shaft 13 supported by a motor case (not shown) and arranged in a circular shape. The winding coils 3 are respectively connected between adjacent commutator pieces 14 and wound around a core of an armature (not shown). Each of the pair of magnets 4 is formed in an arc shape, and is fixed to a motor case (not shown) so as to face each other around an armature (not shown) as shown by a two-dot chain line in FIG.

The low-potential brush 5 is disposed on a motor case (not shown) so as to contact the commutator piece 14 at a predetermined angular position where the magnet 4 is not disposed, and is urged toward the rotating shaft 13.

The high potential side brush 6 for low speed is
Is located at an angular position where the low-potential side brush 5
Are arranged in a motor case (not shown) so as to come into contact with the commutator piece
Is biased to the side.

The high-speed high-potential-side brush 7 is shown in FIGS.
As shown in FIG. 5, the low resistivity portions 7a and 7b having low resistivity are formed so as to sandwich the high resistivity portion 7c having high resistivity in the rotation direction of the commutator 2. Also, the high-potential side high-speed brush 7
As shown in FIG. 2, the width X of the low resistivity portions 7a and 7b in the rotation direction is equal to the width Y of the gap between the adjacent commutator pieces 14.
It is formed slightly smaller.

The high-potential high-speed brush 7 includes a magnet 4
Are arranged at an angle of less than 180 degrees (about 120 degrees in FIG. 1) with respect to the low-potential side brush 5 and are arranged in a motor case (not shown) so as to contact the commutator piece 14. And is urged to the rotating shaft 13 side.

The low-potential-side brush 5 is connected to a low-potential-side power supply (ground) and to a high-speed connection terminal 11 H of the second changeover switch 11. The low-voltage high-potential-side brush 6 is connected to the low-speed connection terminal 10L of the first changeover switch 10.

The low-resistivity portion 7a of the high-speed high-potential-side brush 7 on the low-speed high-potential-side brush 6 side is a high-speed connection terminal of the first changeover switch 10 by a conductor buried and connected to the low-resistivity portion 7a. 10H, and connected to the low-speed connection terminal 10L of the first changeover switch 10 via the first resistor 8.

The low-resistivity portion 7b of the high-speed high-potential-side brush 7 on the low-potential-side brush 5 side is connected to the low-resistivity portion 7b via a second resistor 9 via a second resistor 9 via a conductive wire embedded and connected to the low-resistivity portion 7b. The switch 11 is connected to the low-speed connection terminal 11L.

Movable terminal 10A of first changeover switch 10
Are connected to a high potential power supply via a main power switch 12. The movable terminal 11A of the second switch 11 is connected to a low-potential-side power supply (ground). The first and second changeover switches 10 and 11 are connected to the movable terminal 10.
A and 11A can be switched to be connected to the low-speed connection terminals 10L and 11L or the high-speed connection terminals 10H and 11H. The main power switch 12 according to the present embodiment is connected / disconnected in accordance with the operation of a vehicle wiper switch provided at a vehicle driver's seat (not shown), and the first and second changeover switches 10 and 11 are connected to the same vehicle. The connection is switched according to the operation of the wiper switch.

Next, the operation of the motor 1 configured as described above will be described. The main power switch 12 is connected according to the operation of the vehicle wiper switch, and the movable terminals 10A, 11 of the first and second changeover switches 10, 11 are connected.
When A is connected to the low-speed connection terminals 10L and 11L, the rotating shaft 13 rotates at a low speed. More specifically, the low-speed high-potential-side brush 6 is connected to the high-potential-side power supply, and a driving current is supplied from the low-speed high-potential-side brush 6 to the winding coil 3 via the commutator 2 (commutator piece 14). Since it flows to the potential side brush 5, the armature and the rotating shaft 13 (not shown) rotate at a low speed.

At this time, the high-potential-side power supply voltage and the first potential
In addition, a predetermined voltage is supplied based on the resistance values of the second resistors 8 and 9 and the resistance value of the high resistivity portion 7c. This predetermined voltage is set in accordance with the voltage between adjacent commutator pieces 14 that are not short-circuited at the time of low-speed driving, and in the present embodiment, between the adjacent commutator pieces 14 that are not short-circuited. Is set to be substantially the same as the voltage of Thereby, at the time of low-speed driving,
As shown in FIG. 1, even when the high-potential-side high-speed brush 7 contacts across the adjacent commutator pieces 14, the adjacent commutator pieces 1
The flow of the short-circuit current between the four is suppressed. The predetermined voltage is supplied to the first and second resistors 8 and 9 and the high-resistance portion 7.
It is set by selecting each resistance value of c.

The width X of the low resistivity portions 7a and 7b in the rotational direction is smaller than the width Y of the gap between the adjacent commutator segments 14, so that the adjacent commutator segments 14 are connected to one of the low resistivity portions. 7
a and 7b are not electrically connected only via
The short-circuit current does not occur.

From these facts, as shown in FIG. 3, the current Z based on the induced voltage generated in the winding coil 3 connected between the adjacent commutator pieces 14 (the current Z in the direction opposite to the driving current). ) Is prevented from flowing through the coil 3.

On the other hand, the main power switch 12 is connected according to the operation of the vehicle wiper switch, and the movable terminals 10A, 11A of the first and second changeover switches 10, 11 are connected to the high-speed connection terminals 10H, 11H. Then, the rotating shaft 13 rotates at high speed. More specifically, the low resistivity portion 7a of the high-speed high-potential-side brush 7 on the low-speed high-potential-side brush 6 side is connected to the high-potential-side power supply, and the driving current is supplied from the high-speed high-potential-side brush 7 to the commutator 2 (rectifier). The armature and the rotating shaft 13 (not shown) rotate at high speed because the armature and the rotating shaft 13 are supplied to the winding coil 3 via the sub-piece 14) and flow to the low potential side brush 5.

Next, the characteristic effects of the first embodiment will be described below. (1) Even when the high-potential-side high-speed brush 7 contacts the adjacent commutator pieces 14 during low-speed driving, the adjacent commutator pieces 1
The short circuit current between the four is suppressed. Therefore, as shown in FIG. 3, the current Z based on the induced voltage generated in the winding coil 3
(Current in the opposite direction to the drive current) is suppressed from flowing through the coil 3, and a stable drive current can be passed through the coil 3 as compared with the conventional technique (see FIG. 7). As a result, generation of sparks and electric noise is prevented.

(2) When the main power switch 12 is connected and the movable terminals 10A and 11A of the first and second changeover switches 10 and 11 are connected to the low-speed connection terminals 10L and 11L, respectively, Low resistivity part 7 on the side brush 6 side
a is connected to the high potential side power supply via the first resistor 8, and the low resistivity portion 7 b on the low potential side brush 5 side is connected to the low potential side power supply via the second resistor 9. Therefore, a predetermined voltage is supplied between the low resistivity portions 7a and 7b. By doing so, the first and second resistors 8 and 9 and the high resistivity portion 7
A predetermined voltage can be obtained only by selecting each resistance value of c.

(Second Embodiment) Hereinafter, a second embodiment in which the present invention is embodied in a motor for a vehicle wiper device will be described with reference to FIG. FIG. 4 shows a schematic diagram of the motor 21. In the present embodiment, the same members as those in the first embodiment are denoted by the same reference numerals, and a detailed description thereof will be partially omitted.

As shown in FIG. 4, the motor 21 comprises the commutator 2, the winding coil 3, the pair of magnets 4, the low-potential-side brush 5, and the low-speed high-potential A side brush 6, the high-potential high-side brush 7, first and second changeover switches 22 and 23, and the main power switch 12 are provided.

The low potential side brush 5 is connected to a low potential side power supply (ground). The low-speed high-potential side brush 6
The first changeover switch 22 is connected to the low-speed connection terminal 22L.

The low-resistivity portion 7a of the high-speed high-potential-side brush 7 on the low-speed high-potential-side brush 6 side is a high-speed connection terminal of the first change-over switch 22 by a conductor embedded and connected to the low-resistivity portion 7a. 22H. The low-resistance portion 7b of the high-potential high-side brush 7 on the low-potential side brush 5 side is connected to the high-speed connection terminal 23H of the second changeover switch 23 by a conductor buried in the low-resistance portion 7b. Have been.

The movable terminals 22 A and 23 A of the first and second changeover switches 22 and 23 are connected to a high-potential power supply via the main power switch 12. The second changeover switch 2
No. 3 low-speed connection terminal 23L is not connected to any of them. Then, the first and second changeover switches 22, 23 are
The movable terminals 22A, 23A are connected to the low-speed connection terminals 22L, 23.
It can be switched to connect to L or high-speed connection terminals 22H, 23H. The main power switch 12 according to the present embodiment is connected / disconnected in accordance with the operation of a vehicle wiper switch provided at a vehicle driver's seat (not shown), and the first and second changeover switches 22 and 23 are connected to the same vehicle. The connection is switched according to the operation of the wiper switch.

Next, the operation of the motor 1 configured as described above will be described. The main power switch 12 is connected according to the operation of the vehicle wiper switch, and the movable terminals 22A, 23 of the first and second changeover switches 22, 23 are connected.
When A is connected to the low-speed connection terminals 22L and 23L, the rotating shaft 13 rotates at low speed. More specifically, the low-speed high-potential-side brush 6 is connected to the high-potential-side power supply, and a driving current is supplied from the low-speed high-potential-side brush 6 to the winding coil 3 via the commutator 2 (commutator piece 14). Since it flows to the potential side brush 5, the armature and the rotating shaft 13 (not shown) rotate at a low speed.

At this time, the low resistivity portions 7a and 7b of the high-speed high-potential-side brush 7 are not connected to either. Further, since the width X of the low resistivity portions 7a and 7b in the rotation direction is smaller than the width Y of the gap between the adjacent commutator segments 14, the adjacent commutator segments 14 are connected to one of the low resistivity portions 7a and 7b. And no short-circuit current is generated.

From these, the short-circuit current is suppressed,
The current Z (current in the direction opposite to the drive current) based on the induced voltage generated in the winding coil 3 connected between the adjacent commutator pieces 14 is suppressed from flowing through the winding coil 3 ( (See FIG. 3).

On the other hand, the main power switch 12 is connected in accordance with the operation of the vehicle wiper switch, and the movable terminals 22A, 23A of the first and second changeover switches 22, 23 are connected to the high-speed connection terminals 22H, 23H. Then, the rotating shaft 13 rotates at high speed. More specifically, both low resistivity portions 7a and 7b of the high-speed high-potential-side brush 7 are connected to the high-potential-side power supply, and the driving current is supplied from the high-speed high-potential-side brush 7 to the commutator 2.
Since it is supplied to the winding coil 3 via the (commutator piece 14) and flows to the low potential side brush 5, the armature and the rotating shaft 13 (not shown) rotate at high speed.

Next, the characteristic effects of the second embodiment will be described below. (1) Even when the high-potential-side high-speed brush 7 contacts the adjacent commutator pieces 14 during low-speed driving, the adjacent commutator pieces 1
The short circuit current between the four is suppressed. Therefore, similarly to the first embodiment (see FIG. 3), a current Z (a current in a direction opposite to the drive current) based on the induced voltage generated in the winding coil 3 flows through the winding coil 3. Therefore, a stable drive current can be supplied to the winding coil 3 as compared with the related art (see FIG. 7). As a result, generation of sparks and electric noise is prevented.

(2) During high-speed driving, both low resistivity portions 7a,
Since 7b is connected to the high-potential power supply, the driving current can be supplied more stably from the high-speed high-potential-side brush 7 than when one of the low-resistance portions is connected to the high-potential power supply.

The above embodiments may be modified as follows. The high-speed high-potential-side brush 7 according to each of the above-described embodiments may be configured such that the low-resistivity portion having a low resistivity sandwiches the high-resistivity portion having a high resistivity in the rotation direction of the commutator. The configuration may be changed. For example, it may be changed to the high-speed high-potential-side brush 31 shown in FIG. The high potential side brush 31 for high speed
The low resistivity portions 31a and 31b having low resistivity are formed so as to sandwich the high resistivity portion 31c having high resistivity in the rotation direction of the commutator 2. Further, an insulating layer 31d having a higher resistivity is formed in an intermediate portion of the high resistivity portion 31c. Even in this case, effects similar to the effects of the above embodiment can be obtained.

In the above embodiments, the low resistivity portion 7
Although the width X of the gaps a and 7b is slightly smaller than the width Y of the gap between the adjacent commutator pieces 14, the width X of the low resistivity portions 7a and 7b is the width of the gap between the adjacent commutator pieces 14. If it is Y or less, it may be changed. Even in this case, the same effect as that of the above embodiment can be obtained.

In the first embodiment, the first and second resistors 8 and 9 and the first and second changeover switches 10 and 11
The low resistivity portions 7 of the high-potential high-side brush 7
A predetermined voltage is supplied between the low-resistivity portions 7a and 7b.
As long as a predetermined voltage can be supplied between a and 7b, another voltage supply means may be used. Even in this case, the same effect as the effect (1) of the first embodiment can be obtained.

In the first embodiment, the predetermined voltage is set to be substantially the same as the voltage between the adjacent commutator pieces 14 that are not short-circuited at the time of low-speed driving. What is necessary is just to set according to the voltage between the adjacent commutator pieces 14 in the state where it is not performed. For example, if they are set completely the same, no short-circuit current is generated.

In the above-described embodiments, the number of high-potential-side brushes to which the high-potential power supply is connected is two: the low-speed high-potential-side brush 6 and the high-speed high-potential-side brush 7. However, the number of brushes is changed to three or more. You may. In this case, at least one high-potential-side brush has the same configuration as that of the high-speed high-potential-side brush 7, and when a predetermined high-potential-side brush is connected to the high-potential-side power source, both low-potential brushes of the other high-potential-side brushes become low. A predetermined voltage is supplied between the resistivity sections. Even in this case, effects similar to the effects of the above embodiment can be obtained.

In the above-described embodiments, the high-speed high-potential-side brush 7 is arranged so as to be in contact with the commutator piece 14 at an interval of about 120 degrees with respect to the low-potential-side brush 5. , The angle position where the magnet 4 is arranged,
Any position may be used as long as it is located at an interval of less than 180 degrees with respect to the low-potential-side brush 5, and may be arranged so as to be in contact with the commutator piece 14 at an interval of about 110 degrees with respect to the low-potential-side brush 5. Even in this case, effects similar to the effects of the above embodiment can be obtained.

In the above embodiment, the present invention is embodied as a motor for a vehicle wiper device, but may be changed to a motor used for another device. The technical ideas other than those described in the claims that can be grasped from the above embodiment will be described below together with their effects.

(A) In the motor according to the first aspect,
The motor according to claim 1, wherein the predetermined voltage is set corresponding to a voltage between the adjacent commutator pieces that are not short-circuited. With this configuration, when the high-potential-side brush that is not selected by the switch contacts across the adjacent commutator pieces, the two low-resistance portions are adjacent to each other in a state that is not short-circuited by the voltage supply unit. Since the voltage set according to the voltage between the commutator pieces is supplied, the short-circuit current between the adjacent commutator pieces can be suppressed. Thus, it is possible to suppress a current (a current in a direction opposite to the drive current) based on the induced voltage generated in the winding coil connected between the adjacent commutator pieces from flowing through the winding coil. .

(B) In the motor according to claim 6,
When the switch is switched to connect the high potential side brush having the low resistivity portion and the high resistivity portion to the high potential side power supply, the switch switches both the low resistivity portion and the high potential side. A motor to which a power supply is connected.
With this configuration, since both low-resistance portions are connected to the high-potential power supply, the drive current can be supplied more stably than when one of the low-resistance portions is connected to the high-potential power supply. .

(C) In the motor according to claim 6 or (b), the high-potential-side brush is in contact with the commutator piece at a position of 180 degrees with respect to the low-potential-side brush. A low-voltage high-potential-side brush disposed, and a high-speed high-potential-side brush disposed to be in contact with the commutator piece at a position less than 180 degrees from the low-potential-side brush; A motor, wherein the low-speed high-potential-side brush is driven at a low speed when connected to the high-potential-side power supply, and the high-speed high-potential-side brush is driven at a high speed when connected to the high-potential-side power supply. With this configuration, the low-speed high-potential-side brush is driven at a low speed when it is connected to the high-potential-side power supply, and the high-speed high-potential-side brush is driven at a high speed when it is connected to the high-potential-side power supply.

[0058]

As described in detail above, according to the present invention,
In a motor in which the driving speed can be switched by selecting and connecting a plurality of brushes, it is possible to provide a motor capable of suppressing a short-circuit current and allowing a stable driving current to flow through a winding coil.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a motor according to a first embodiment.

FIG. 2 is an explanatory diagram for explaining a high-potential-side high-speed brush.

FIG. 3 is a coil current characteristic diagram of a winding coil according to the first embodiment.

FIG. 4 is a schematic view of a motor according to a second embodiment.

FIG. 5 is an explanatory diagram for explaining another example of a high-speed high-potential-side brush.

FIG. 6 is a schematic view of a motor according to the related art.

FIG. 7 is a coil current characteristic diagram of a winding coil according to a conventional technique.

[Description of References] 2 ... commutator, 3 ... winding coil, 5 ... low-potential side brush, 6
... High potential side brush for low speed (high potential side brush), 7, 31
… High-potential-side high-speed brush (high-potential-side brush), 8… First
Resistance (first resistance), 9 second resistance (second resistance), 1
0: first switch (switch), 11: second switch, 14: commutator piece, 22: first switch (switch), 23: second switch (switch), 7
a, 7b, 31a, 31b ... low resistivity part, 7c, 31c
... High resistivity part.

Claims (6)

[Claims] 1. A commutator having a plurality of commutator pieces arranged in a circle, a winding coil connected between adjacent ones of the commutator pieces, and a contact with the commutator pieces at a predetermined angular position. A low-potential-side brush connected to a low-potential-side power supply, and a plurality of high-potentials disposed so as to contact the commutator strip at predetermined angular intervals with respect to the low-potential-side brush. And a switch for selecting any one of the plurality of high-potential-side brushes and connecting to a high-potential-side power supply, wherein at least one of the high-potential-side brushes is The low resistivity portion having a low resistivity sandwiches the high resistivity portion having a high resistivity in the rotational direction of the commutator, and the width of the low resistivity portion in the rotational direction is between the adjacent commutator pieces. Is formed to be less than the width of the gap of When the switch is switched to connect the predetermined high-potential-side brush and the high-potential-side power supply, a voltage supply unit that supplies a predetermined voltage between the low-resistivity portions is provided. And the motor. 2. The motor according to claim 1, wherein the predetermined voltage is set to be substantially the same as a voltage between the adjacent commutator pieces that are not short-circuited. 3. The motor according to claim 1, wherein the voltage supply means is configured to switch between the predetermined high-potential-side brush and the high-potential-side power supply when the switch is switched to one. Connecting the low resistivity portion to the predetermined high potential side brush via a first resistor, and connecting the other low resistivity portion to the low potential side power supply via a second resistor. A motor characterized by the following. 4. The motor according to claim 1, wherein the high-potential-side brush contacts the commutator segment at a position spaced by 180 degrees with respect to the low-potential-side brush. A low-voltage high-potential-side brush, and a high-speed high-potential-side brush disposed to be in contact with the commutator piece at a position less than 180 degrees from the low-potential-side brush, A motor that performs low-speed driving when the low-speed high-potential-side brush is connected to the high-potential-side power supply, and performs high-speed driving when the high-speed high-potential-side brush is connected to the high-potential-side power supply. 5. The motor according to claim 4, wherein the high-potential-side brush having the low-resistivity portion and the high-resistivity portion is the high-speed high-potential-side brush; When the switch is switched to connect the high potential side brush for low speed and the high potential side power supply, the predetermined voltage is supplied between the low resistivity portions of the high potential side brush for high speed. A motor characterized in that: 6. A commutator having a plurality of commutator pieces arranged in a circle, a winding coil connected between adjacent ones of the commutator pieces, and a contact with the commutator pieces at a predetermined angular position. A low-potential-side brush connected to a low-potential-side power supply, and a plurality of high-potentials disposed so as to contact the commutator strip at predetermined angular intervals with respect to the low-potential-side brush. And a switch for selecting any one of the plurality of high-potential-side brushes and connecting to a high-potential-side power supply, wherein at least one of the high-potential-side brushes is The low resistivity portion having a low resistivity sandwiches the high resistivity portion having a high resistivity in the rotational direction of the commutator, and the width of the low resistivity portion in the rotational direction is between the adjacent commutator pieces. Is formed to be less than the width of the gap of When the switch is switched to connect the predetermined high-potential-side brush and the high-potential-side power supply, the two low-resistivity portions of the other high-potential-side brushes are not connected to any of them. And the motor.