JP4104954B2 - Wiper motor drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a wiper motor driving device for wiping a window glass of an automobile.
[0002]
[Prior art]
Usually, the operation speed of the wiper blade can be switched between high and low (high / low). As shown in FIG. 11, the wiper motor 100 is equipped with a high-speed driving brush 103 as a third brush in addition to the low-speed driving brush 101 and the common brush 102, as shown in FIG. Then, the rotation of the motor can be changed from low speed to high speed by switching the energization circuit for the rotor from one using the low speed driving brush 101 to one using the high speed driving brush 103. In this case, the low-speed driving brush 101 and the common brush 102 are usually disposed at positions facing each other by 180 degrees, and the high-speed driving brush 103 is disposed at a position shifted by a predetermined angle with respect to the low-speed driving brush 101.
[0003]
By the way, in the case of the wiper motor having the structure in which the brush for high speed driving is provided as the third brush in this way, it is pointed out that the high speed driving brush is always in contact with the commutator even when driving at low speed, so that it has a bad influence. ing. Specifically, the effective coil is short-circuited when the brush for high-speed driving contacts the commutator pieces (segments) of the commutator at the same time during low-speed driving. The problem is that noise and vibration are generated.
[0004]
Therefore, in order to reduce these influences, techniques such as Japanese Patent Laid-Open No. 2001-231219 take measures such as increasing the specific resistance of the high-speed driving brush.
[0005]
[Patent Document 1]
JP-A-2001-231219 [0006]
[Problems to be solved by the invention]
However, as long as the high-speed driving brush is provided, there is a problem that a certain level of output reduction cannot be avoided, and the desired effect cannot be obtained sufficiently.
[0007]
In view of the above circumstances, an object of the present invention is to provide a wiper motor driving device that can reduce noise and vibration without short-circuiting an effective coil during low-speed driving.
[0008]
[Means for Solving the Problems]
The invention of claim 1 includes a wiper motor for driving the motor vehicle wiper device, a second motor drive circuit you want to rotate. In the rotational direction of the rotational direction opposite to the rotor of the wiper motor first rotational direction or the first made, the wiper motor, a first pair for supplying current to the windings of the rotor in sliding contact with the commutator fixed to the armature shaft provided in said rotor, a second brush, the second The first brush is supported by a first brush holder fixed at a predetermined position, and the second brush is a second brush whose boss portion is directly fitted to the outer periphery of the armature shaft of the rotor. of which is supported by the brush holder, when the rotor Ru is rotated in the first rotational direction, the contact portion of the boss portion and the armature shaft of the second brush holder, and of the commutator and the second brush Pressure contact By both the frictional force generated by the sliding rotates the second brush holder to the first brush position for low-speed driving, when and Ru rotate the rotor in the second rotational direction, by the two frictional force The second brush holder is rotated to a second brush position for high-speed driving, and the second brush holder is connected to the second brush as the second brush holder rotates. A reel-shaped pigtail receiving portion for absorbing expansion and contraction of the pigtail is formed by winding the pigtail, and the motor drive circuit performs a second rotation of the rotor and a current for rotating the rotor in the first rotation direction. Current switching means is provided for selectively switching the current rotating in the direction and supplying the current to the first and second brushes.
[0009]
In the wiper motor driving apparatus of the present invention, the boss portion of the second brush holder is directly fitted to the outer periphery of the armature shaft so as to be freely rotatable, so that the rotation direction of the rotor of the wiper motor is the first rotation direction or the first rotation direction. When the rotation direction is changed to the second rotation direction opposite to the rotation direction of 1, both the boss portion of the second brush holder and the contact portion of the armature shaft and the sliding between the contact portion of the second brush and the commutator are generated. Due to the frictional force, the second brush holder rotates following the rotation direction of the rotor, and is set to a predetermined position of the first brush position for low speed driving or the second brush position for high speed driving. Therefore, the rotor can be driven to rotate at a low speed by operating the current switching means to rotate the rotor in the first rotation direction. Also, by manipulating the current switching means to rotate the rotor in a second rotational direction, Ru can be driven rotating the rotor at high speed. Teeth may, brush only is a pair necessary for driving, since no third brush provided, effective coil by the third brush is short-circuited during low-speed driving, or which causes the output falls, the noise And vibration will not occur. Further, since the pigtail housing portion is provided in the second brush holder, the pigtail can be stably pulled out from the second brush.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
The wiper motor drive device of the embodiment includes a wiper motor that drives a wiper device of an automobile and a motor drive circuit that drives the wiper motor. FIG. 1 is a cross-sectional view showing the overall configuration of the wiper motor 1. The wiper motor 1 includes a motor unit 2 and a gear unit 3. The motor unit 2 includes a motor case 11 that functions as a yoke, a plurality of magnets 12 fixed to the inner periphery of the motor case 11, and a rotor 13 disposed on the inner periphery side of the magnet 12. The rotor 13 supports both ends of an armature shaft 14 disposed at the center of the rotor 13 by two bearings 5 and 6 that are fitted and fixed to a gear case flange 4 that also serves as a rear end portion of the motor case 11 and a front wall of the motor portion, respectively. Thus, the magnet 12 is rotatably supported on the inner peripheral side.
[0016]
The motor unit 2 further includes a brush device 20 and a commutator 16 fixed to an intermediate portion of the armature shaft 14 as a mechanism for energizing the winding 13 a of the rotor 13. The motor unit 2 of the wiper motor 1 is a two-speed DC motor having one fixed brush (a first brush called a common brush) and one movable brush (a second brush that serves both as a low brush and a high brush). The brush device 20 is rotatably mounted on the outer periphery of the armature shaft 14 and a fixed brush holder (first brush holder) 21 fixed at a predetermined position of the gear case flange 4. And a movable brush holder (second brush holder) 22.
[0017]
2 is a front view of the brush device 20 as viewed from the direction of arrows XX in FIG. 1, FIG. 3 is a perspective view of the brush device as viewed from the same direction, and FIG. 4 is a view of the brush device as viewed from the opposite side of FIG. It is a perspective view.
[0018]
As shown in FIGS. 2 and 3, the commutator 16 (see FIG. 2) is provided in each holding cylinder 21a, 22a of the fixed brush holder 21 as the first brush holder and the movable brush holder 22 as the second brush holder . The first brush 23 and the second brush 24 that are in sliding contact with each other are held so as to be slidable in the pressing direction against the commutator 16 (in the radial direction of the rotor 13). The drive current is supplied to the rotor 13 using 23 and 24. The brushes 23 and 24 are always in pressure contact with the commutator 16 by springs 28 mounted on the brush holders 21 and 22.
[0019]
The first brush 23 held by the fixed brush holder 21 is a common brush, and the second brush 24 held by the movable brush holder 22 is a low brush (low speed driving brush) and a high brush (high speed driving brush). The movable brush 24 is movable, and can move between a first brush position for low speed driving shown in FIG. 2A and a second brush position for high speed driving shown in FIG. 2B. It is like that. In other words, the movable brush holder 22 that holds the movable brush 24 is pulled by the rotation of the rotor 13 when the rotor 13 rotates in the first rotation direction (the direction of the arrow A in the figure), and is the first for low-speed driving. When the rotor 13 is rotated to the brush position and the rotor 13 is rotated in the second rotation direction opposite to the first rotation direction (in the direction of arrow B in the figure), the second high-speed driving second is drawn by the rotation of the rotor 13. It is designed to rotate to the brush position. Therefore, the boss portion 22b of the movable brush holder 22 is directly fitted to the outer periphery of the armature shaft 14 so as to freely rotate, and the rotational force of the armature shaft 14 is caused by the frictional force between the boss portion 22b and the armature shaft 14. 22 is transmitted directly.
[0020]
The first brush position for low speed driving is a position facing the common brush 23 by 180 degrees, and the second brush position for high speed driving is a predetermined angle with respect to the first brush position for low speed driving. The position is shifted by (for example, 70 degrees). As it can be reliably selectively positioned and fixed the movable brush holder 22 in these positions, as shown in FIG. 2, the motor case 11 or the gear case flange 4, to limit the rotation of the movable brush holder 22 Stoppers 31 and 32 are provided.
[0021]
Pigtails 25 and 26 are connected to the brushes 23 and 24, respectively. In particular, the pigtail 26 connected to the movable brush 24 is placed on the brush holder 22 in order to absorb expansion and contraction accompanying the rotation of the movable brush holder 22. It is once wound around the provided reel-like pigtail housing 27 and then stably pulled out to the fixed brush holder 21 side. Thereby, even when the movable brush holder 22 is rotated, excessive stress does not act on the pigtail 26.
[0022]
In the motor unit 2 configured in this manner, as shown in FIG. 5, when the rotor 13 rotates, the contact portion between the boss portion 22 b of the movable brush holder 22 and the armature shaft 14, and the movable brush 24 and the rectifier resulting frictional force by the sliding of the contact portion between the child 16 (shown in the drawing small arrows), respectively. Therefore, the rotation of the rotor 13 is transmitted to the movable brush holder 22 by the action of these frictional forces. As a result, as shown in FIG. 2A, when the rotor 13 and the armature shaft 14 rotate counterclockwise in the first rotation direction in the drawing, the movable brush holder 22 is set at the first brush position for low speed driving. On the contrary, as shown in FIG. 2 (b), when the rotor 13 and the armature shaft 14 rotate to the right, which is the second rotation direction in the drawing, the movable brush holder 22 and the movable brush 24 become the second for high-speed driving. Set to brush position.
[0023]
Next, a motor drive circuit 80 for driving the wiper motor 1 will be described with reference to FIG. The motor drive circuit 80 includes a wiper switch 50 having three operation positions of OFF (OFF) -LOW (low speed) -HIGH (high speed), and an automatic stop mechanism 60 for stopping the wiper blade at a fixed position. It is. The auto stop mechanism 60 is usually incorporated in the wiper motor 1. The motor drive circuit 80 includes a first relay 71 and a second relay 72 as current switching means for switching the rotation direction of the B terminal, H terminal, E terminal, L terminal, P terminal, and wiper motor 1. Is provided. The B terminal is fixedly connected to the positive electrode of the battery, and the E terminal is fixedly connected to the ground.
[0024]
The auto-stop mechanism 60 has a fixed terminal plate 61 having a notch 61a in a part in the circumferential direction, and a movable terminal 62 that slides on the fixed terminal plate 61 by rotating synchronously with the output shaft of the wiper motor 1. The fixed terminal plate 61 is connected to the ground, and the movable terminal 62 is connected to the P terminal.
[0025]
The wiper switch 50 has a function of connecting the L terminal and the P terminal at the OFF position, connecting the L terminal and the E terminal at the LOW position, and connecting the H terminal and the E terminal at the HIGH position. The first relay 71 has an exciting coil 71a, a movable contact 71b, a normally closed fixed contact 71c, and a normally open fixed contact 71d. When the exciting coil 71a is not excited, the movable contact 71b is brought into contact with the normally closed fixed contact 71c. has a structure in which the movable contact 71b is conductive contact with the normally open fixed contact 71 d when the exciting coil 71a is excited. Similarly, the second relay 72 has an exciting coil 72a, a movable contact 72b, a normally closed fixed contact 72c, and a normally open fixed contact 72d. When the exciting coil 72a is not excited, the movable contact 72b contacts the normally closed fixed contact 72c. conduction, and the exciting coil 72a is a structure in which the movable contact 72b is conductive contact with the normally open fixed contact 72d when energized.
[0026]
The exciting coil 71a of the first relay 71 is connected to the B terminal and the L terminal, and the exciting coil 72a of the second relay 72 is connected to the B terminal and the H terminal. The normally closed fixed contact 71c of the first relay 71 and the normally closed fixed contact 72c of the second relay 72 are connected to the B terminal, and the normally open fixed contact 71d of the first relay 71 and the normally open fixed contact of the second relay 72 are connected. 72d is connected to the E terminal. The movable contact 71 b of the first relay 71 is connected to the common brush 23, and the movable contact 72 b of the second relay 72 is connected to the movable brush 24.
[0027]
Next, the operation will be described. FIG. 6 shows a state where the wiper switch 50 is in the OFF position and the wiper motor 1 is stopped at a predetermined stop position.
[0028]
(1) In this state, when the wiper switch 50 is operated from OFF to LOW, a current flows through a path indicated by a thick line in FIG. That is, since the L terminal is connected to the E (earth) terminal, the exciting coil 71a of the first relay 71 is excited, and the movable contact 71b is switched from the normally closed fixed contact 71c to the normally open fixed contact 71d. Accordingly, the energization circuit of the wiper motor 1 is closed, and current flows in the order of the B terminal, the movable brush 24, the commutator and rotor, the common brush 23, and the E terminal, so that the wiper motor 1 rotates in the forward direction (left rotation in the figure). To do. At this time, since the movable brush 24 is attracted by the rotation of the rotor and set at the brush position for low speed driving, the wiper motor 1 rotates forward at low speed.
[0029]
(2) When the wiper switch 50 is operated from OFF to HIGH, a current flows through a path indicated by a thick line in FIG. That is, since the H terminal is connected to the E (earth) terminal, the exciting coil 72a of the second relay 72 is excited, and the movable contact 72b is switched from the normally closed fixed contact 72c to the normally open fixed contact 72d. Accordingly, the energization circuit of the wiper motor 1 is closed, and current flows in the order of the B terminal, the common brush 23, the commutator and rotor, the movable brush 24, and the E terminal, and the wiper motor 1 rotates in the reverse direction (right rotation in the figure). To do. At this time, since the movable brush 24 is attracted by the rotation of the rotor and set at the brush position for high-speed driving, the wiper motor 1 rotates in reverse at high speed.
[0030]
(3) Further, when the wiper switch 50 is turned OFF during the LOW operation, the stage where the wiper blade is not at the predetermined stop position (that is, the stage where the movable terminal 62 of the auto-stop mechanism 60 is on the fixed terminal plate 61) A current flows through a path indicated by a thick line in FIG. That is, since the L terminal is connected to the P terminal grounded by the auto-stop mechanism 60, the excitation of the exciting coil 71a of the first relay 71 is maintained. Therefore, the circuit at the time of LOW is maintained, current flows in the order of the B terminal, the movable brush 24, the commutator and rotor, the common brush 23, and the E terminal, and the wiper motor 1 maintains the low-speed forward rotation.
[0031]
(4) Eventually, when the wiper blade comes to a predetermined stop position, an armature short circuit indicated by a thick line in FIG. 10 is formed. That is, the movable terminal 62 of the auto-stop mechanism 60 is positioned in the notch 61a of the fixed terminal plate 61, the conduction between the movable terminal 62 and the fixed terminal plate 61 is released, and the P terminal is separated from the ground, and as a result, the first relay The excitation coil 71a of 71 is not excited. Therefore, the movable contact 71b returns from the normally open fixed contact 71d to the normally closed fixed contact 71c, an armature short circuit is formed to short- circuit the common brush 23 and the movable brush 24, and the wiper motor 1 is suddenly stopped.
[0032]
(5) When the wiper switch 50 is turned OFF during HIGH operation, the exciting coil 72a of the second relay 72 is de-energized, and the movable contact 72b returns from the normally open fixed contact 72d to the normally closed fixed contact 72c side. . However, when the wiper blade is not at the predetermined stop position, the P terminal and the L terminal that are grounded by the auto stop mechanism 60 are connected, so that the excitation coil 71a of the first relay 71 is excited and the wiper motor 1 is excited. Rotates at low speed. The subsequent operation is the same as (4). That is, when the wiper blade eventually reaches the predetermined stop position, the P terminal is separated from the ground, so that the exciting coil 71a of the first relay 71 is de-energized, the movable contact 71b returns to the normally open fixed contact 71c side, and the armature A short circuit is formed and the wiper motor 1 stops suddenly.
[0033]
Thus, when the wiper switch 50 is set to LOW, the wiper motor 1 can be rotated forward at low speed, and when it is set to HIGH, the wiper motor 1 can be rotated backward at high speed. That is, the speed of the wiper motor 1 can be switched simply by switching the rotation direction. Moreover, since the brushes 23 and 24 are only provided with a pair necessary for driving and not the third brush, the effective coil is short-circuited by the third brush during low-speed driving, and the output is thereby reduced. Noise and vibration will not occur.
[0034]
Even if the wiper motor 1 rotates in the forward and reverse directions, the movement is only converted into a reciprocating rotational movement of the pivot shaft by the link mechanism of the wiper device. Therefore, the wiper blade wiping operation is affected by the rotation direction of the wiper motor 1. Does not come out. For example, when the wiper motor 1 rotates in the forward direction, the pivot shaft reciprocates in the forward and reverse directions by the action of the link mechanism, whereby the wiper blade reciprocates at a low speed between the upside down positions. Further, when the wiper motor 1 rotates in the reverse direction, the pivot shaft reciprocates in the forward and reverse directions by the function of the link mechanism, whereby the wiper blade reciprocates at a high speed between the upside down positions.
[0035]
【The invention's effect】
As described above, according to the wiper motor driving device of the present invention, the boss portion of the second brush holder is directly fitted to the outer periphery of the armature shaft so as to be freely rotatable. When the rotation direction is changed to 1 or the second rotation direction opposite to the first rotation direction, the boss portion of the second brush holder and the contact portion of the armature shaft, and the pressure contact between the second brush and the commutator The first brush position for low-speed driving or the second brush for high-speed driving that is a predetermined position by the second brush holder being rotated following the rotation direction of the rotor by both frictional forces generated by sliding of the parts. Set to position. Therefore, the rotational speed of the rotor can be switched simply by changing the rotational direction of the rotor between the low speed operation and the high speed operation. In addition, since the brush for energizing the rotor is only provided with a pair necessary for driving, and the third brush is not provided, the effective coil is short-circuited by the third brush during low-speed driving, thereby reducing the output. No noise or vibration. Further, since the pigtail housing portion is provided in the second brush holder, the pigtail can be stably pulled out from the second brush.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an overall configuration of a wiper motor that constitutes a wiper motor driving apparatus according to an embodiment of the present invention.
FIG. 2 is a front view of the brush device as seen from the direction of arrows XX in FIG.
FIG. 3 is a perspective view of the brush device viewed from the same direction as FIG.
4 is a perspective view of the brush device viewed from the opposite direction to FIG. 3. FIG.
FIG. 5 is an explanatory diagram of a frictional force that contributes to rotation of the movable brush holder of the brush device.
FIG. 6 is a diagram showing a motor drive circuit constituting the wiper motor drive device of the embodiment of the present invention.
FIG. 7 is a diagram illustrating a path through which a current flows when a wiper switch is operated LOW by a thick line.
FIG. 8 is a diagram showing a path through which a current flows when a wiper switch is operated to HIGH with a thick line.
FIG. 9 is a diagram illustrating a path through which a current flows when a wiper blade is not in a predetermined stop position when a wiper switch is turned off, by a thick line.
10 is a diagram showing a path of an armature short when a braking force is generated at the next stage of FIG. 9 by a bold line.
FIG. 11 is a diagram illustrating a driving circuit for a conventional wiper motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Wiper motor 13 Rotor 13a Winding 14 Armature shaft 16 Commutator 21 Fixed brush holder (1st brush holder)
22 Movable brush holder (second brush holder)
22b Boss portion 23 Common brush (first brush)
24 Movable brush (second brush)
26 Pigtail 27 Pigtail receiving portion 71 First relay (current switching means)
72 Second relay (current switching means)
80 Motor drive circuit

Claims (1)

Consists of a wiper motor for driving a vehicle wiper device, and the rotor of the wiper motor first rotational direction or rotational direction opposite to the first second motor drive circuit you want to rotate. In the direction of rotation,
The wiper motor, a first pair for supplying current to the windings of the rotor in sliding contact with the commutator fixed to the armature shaft provided in said rotor, a second brush,
The first brush is supported by a first brush holder fixed at a predetermined position;
The second brush is supported by a second brush holder in which a boss portion is directly fitted to the outer circumference of the armature shaft of the rotor so as to freely rotate.
When the rotor Ru is rotated in the first rotational direction, caused by the sliding of the contact portion of the armature shaft and the boss portion of the second brush holder, and press-contact portion of the commutator and the second brush The second brush holder is rotated to the first brush position for low speed driving by both frictional forces ,
And when the rotor Ru is rotated in the second rotational direction, the second brush holder is rotated to a second brush position for high-speed driving by the two frictional forces,
The second brush holder has a reel-shaped pigtail accommodating portion for absorbing expansion and contraction of the pigtail by winding a pigtail connected to the second brush as the second brush holder rotates. Formed,
The motor drive circuit selectively switches between a current for rotating the rotor in the first rotation direction and a current for rotating the rotor in the second rotation direction, and supplies the current to the first and second brushes. A wiper motor drive device comprising switching means.

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