JP2010068592A - Wiper motor and its rotational frequency switching method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an highly efficient and inexpensive DC wiper-motor with brushes, which can vary the rotational speed of the motor in three speed steps including a low speed, a high speed and an ultra-high speed, receiving little influence of electromagnetic wave noises. <P>SOLUTION: The wiper-motor includes a common brush 21, a low speed brush 22 and a high speed brush 23, each being in slide contact with a commutator. The wiper-motor energizes the common brush 21 and the low speed brush 22, during driving at the low speed rotation, to supply a drive power source to an armature through the commutator to be driven at an output shaft rotation frequency of 30 to 50 rpm, and energizes the common brush 21 and the high speed brush 23, during driving at the high speed rotation, to supply a drive power source to the armature through the commutator to be driven at an output shaft rotation frequency of 50 to 80 rpm. The wiper-motor energizes the low speed brush 22 and the high speed brush 23, during driving at the ultra high speed rotation, to supply a drive power source through the commutator to be driven at an output shaft rotation frequency of 100 to 160 rpm. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a brushed DC motor, and more particularly to a speed control technique for a brushed DC motor capable of varying the motor rotation speed.

Conventionally, DC motors with brushes are widely used as drive sources for various devices because they are small, easy to control with high torque, and low in cost. For example, a DC motor capable of switching a driving speed is used in a wiper device of an automobile. Examples of such a DC motor include a wiper motor disclosed in Patent Document 1 (Japanese Patent Laid-Open No. 2004-153942), Patent Document 2 (Japanese Patent Laid-Open No. 2001-1867), and the like. FIG. 1 is a cross-sectional view showing the overall configuration of the wiper motor. The wiper motor 1 includes a motor unit 2 and a gear unit 3.
The motor unit 2 includes a motor housing 11 that functions as a yoke, a plurality of magnets 12 fixed to the inner periphery of the motor housing 11, and an armature 13 disposed on the inner periphery side of the magnet 12. The armature 13 supports both ends of the rotary shaft 14 disposed at the center of the armature 13 by bearings 5 and 6 that are fitted and fixed to the gear case flange 4 that also serves as the rear end portion of the motor housing 11 and the front wall of the motor portion, respectively. Thus, the magnet 12 is rotatably supported on the inner peripheral side. The motor unit 2 further includes a brush device 20 and a commutator 16 as an energization mechanism for the armature 13. The commutator 16 is fixed to the rotary shaft 14 supported by the bearings 5 and 6 and includes a plurality of commutator pieces arranged in a circle on the outer periphery thereof. A winding coil wound around the core of the armature 13 is connected to each commutator piece.
A worm gear 7 is formed at a portion where the rotating shaft 14 extends into the gear portion 3, and the output shaft 8 is rotated through a worm wheel reduction gear.

  FIG. 2 shows an AA cross section of FIG. As shown in FIG. 2, a common brush 21, a low speed brush 22, and a high speed brush 23 are slidably attached to the commutator 16 as a brush device 20 in the gear case flange 4. The common brush 21 is housed and held in a brush holder 24 so as to come into contact with the commutator 16 at a predetermined angular position of the rotating shaft 14. The low-speed brush 22 is accommodated and held in the brush holder 25 so as to come into contact with the commutator 16 at positions spaced by 180 degrees with respect to the common brush 21. The high-speed brush 23 is accommodated and held in the brush holder 26 so as to come into contact with the commutator 16 at positions of about 120 degrees in the counterclockwise rotation direction with respect to the common brush 21. As described above, the motor unit 2 of the wiper motor 1 is configured as a two-speed DC motor including the common brush 21, the low-speed brush 22, and the high-speed brush 23.

  FIG. 3 shows a BB cross section of FIG. As shown in FIG. 3, two magnets 12 (corresponding to N pole and S pole) are arranged to face each other around the rotation shaft 14.

  FIG. 4 schematically shows the connection between the common brush 21, the low speed brush 22, and the high speed brush 23 and the DC power source 30 when the speed is set to low speed. The common brush 21 is connected to the cathode (ground) 32 of the DC power supply 30. The low speed brush 22 and the high speed brush 23 are connected to the anode 31 of the DC power supply 30 via a changeover switch (not shown). When the low speed mode is set, the common brush 21 is connected to the cathode (ground) 32 of the DC power supply 30, the low speed brush 22 is connected to the anode 31 of the DC power supply 30, and the high speed brush 23 is not connected to the DC power supply 30. . FIG. 5 schematically shows the general arrangement of the common brush 21, the low speed brush 22, and the high speed brush 23 and the connection relationship with the DC power source 30 when set at high speed. When the high speed mode is set, the common brush 21 is connected to the cathode (ground) 32 of the DC power supply 30, the high speed brush 23 is connected to the anode 31 of the DC power supply 30, and the low speed brush 22 is not connected to the DC power supply 30. . That is, the low-speed brush 22 and the high-speed brush 23 are selected and connected to the anode 31 of the DC power supply 30 by switching a switch (not shown).

In the wiper motor 1 configured as described above, when the low-speed brush 22 is connected to the anode 31 of the DC power supply 30 by switching a changeover switch (not shown), the drive current is passed from the low-speed brush 22 via the commutator 16. Since it is supplied to the winding coil and flows to the common brush 21, the armature rotates at a low speed. Further, when the high-speed brush 23 is connected to the anode 31 of the DC power supply 30 by switching a changeover switch (not shown), the drive current is supplied from the high-speed brush 23 to the winding coil via the commutator 16. The armature rotates at a high speed. As shown in FIG. 1, the end of the rotating shaft 14 of the armature is a worm gear. The rotation of the armature is decelerated by the worm and the worm wheel, and the crankshaft that is the rotating shaft of the worm wheel rotates. . The automobile wiper device has an intermittent mode, a low speed mode (Lo), and a high speed mode (Hi). The rotation speed of the output shaft 8 in the intermittent mode and the low speed mode is 30 to 50 rpm, and the high speed mode is 50 to 80 rpm. is there.
JP 2004-153942 A JP 2001-1867 A Japanese Patent No. 40000245 (International Publication No. WO2000 / 071397) Japanese Patent Laid-Open No. 3-98490

  The current car wiper device has a big problem that when it rains heavily, such as when the rainfall exceeds 50mm, even if it is wiped away in high speed mode, the next heavy rain falls and the front cannot be seen. is there. As a method for solving this problem, a method is disclosed in which, in the case of heavy rain, the wiping range of the wiper device is halved, the number of times of wiping is doubled, and the heavy rain is wiped away to secure visibility. Patent Document 3; Patent No. 40000245 (International Publication No. WO2000 / 071397)]. That is, the number of wiping operations can be doubled by reducing the wiper arm movement distance when wiping without changing the wiping speed of the wiper arm, and the inertial action acting on the wiper arm is high (Hi) Since it is the same as the mode, there is no particular problem in terms of durability. In this wiper device, it is necessary to increase the number of times of wiping twice as high as the high-speed (Hi) mode in the case of heavy rain, so that 150 rpm is newly required as the rotation speed of the wiper motor. That is, the rotational speed of the output shaft 8 is required to be 30 to 50 rpm in the intermittent mode and the low speed mode, 50 to 80 rpm in the high speed mode, and 100 to 160 rpm in the extremely high speed mode in severe rain.

  As a device for switching the wiper motor at a speed of three or more stages, there is a wiper device disclosed in Japanese Patent Laid-Open No. 3-98490. In this wiper motor, for example, in order to obtain an intermediate speed between low speed and high speed, the low speed brush 22 and the high speed brush 23 are short-circuited, and the short-circuited high speed brush and the high speed brush are connected to the anode 31 of the DC power supply 30. The common brush 21 is connected to the cathode (ground) 32 of the DC power supply 30. When the low-speed brush 22 and the high-speed brush 23 are short-circuited in this way, a short-circuit current flows in the armature coil between the low-speed brush 22 and the high-speed brush 23, and this short-circuit current generates torque in the direction opposite to the rotational direction. Therefore, the intermediate speed is obtained using the torque in the reverse direction. However, according to the technique disclosed in Patent Document 4, a short-circuit current flows through the armature coil between the low-speed brush 22 and the high-speed brush 23, which causes power loss and greatly reduces the efficiency of the wiper motor. There's a problem. In addition, as a method for controlling the speed of the DC motor, there is a method of changing the driving voltage of the motor. For example, a method of changing the speed by a DC-DC converter or a pulse width modulation (PWM) method is used. However, the DC-DC converter and the pulse width modulation (PWM) method are generally expensive and have a drawback of increasing the manufacturing cost. In addition, the DC-DC converter generates electromagnetic wave noise accompanying switching operation, which has a drawback of affecting the in-vehicle radio as noise.

  The present invention has been made from such a background. The purpose of the present invention is high efficiency, low cost, little influence of electromagnetic noise, and motor rotation speed in three stages: low speed, high speed, and ultra-high speed. It is an object to provide a DC wiper motor with a brush that can be varied.

The gist of the invention according to claim 1 of the present invention includes a common brush, a low-speed brush, and a high-speed brush that are in sliding contact with the commutator, and energizes the common brush and the low-speed brush during low-speed rotation driving to provide the rectification. In a wiper motor comprising switching means for supplying driving power to an armature via a child and energizing the common brush and the high-speed brush during high-speed rotation driving and supplying driving power to the armature via the commutator In the wiper motor, the switching means switches so that the low-speed brush and the high-speed brush are energized to supply drive power to the armature through the commutator during ultra-high-speed rotation driving.
The gist of the invention according to claim 2 of the present invention is that a common brush, a low speed brush, and a high speed brush that are in sliding contact with the commutator are provided, and the common brush and the low speed brush are energized during low-speed rotation driving. Drive power is supplied to the armature through the commutator, and the output shaft is driven at 30 to 50 rpm. During high-speed rotation driving, the common brush and the high-speed brush are energized through the commutator. In a wiper motor that supplies drive power to the armature and drives at 50 to 80 rpm as the rotation speed of the output shaft, during ultra-high speed rotation driving, the low-speed brush and the high-speed brush are energized and the electric motor is connected via the commutator. A wiper motor is characterized in that a drive power is supplied to the child and the output shaft is driven at a rotational speed of 100 to 160 rpm.
Further, the gist of the invention according to claim 3 of the present invention is to supply a driving power to the armature via the commutator by connecting a DC power source to the low speed brush and the high speed brush at the time of ultra high speed rotation driving. 3. A wiper motor according to claim 2, further comprising switching means for performing the above operation.
The gist of the invention according to claim 4 of the present invention is that the switching means connects the cathode of the DC power source to the brush for low speed and the anode of the DC power source to the brush for high speed during ultra-high speed rotation driving. It exists in the wiper motor of Claim 3 characterized by the above-mentioned.
The gist of the invention according to claim 5 of the present invention is that the switching means connects the anode of a DC power source to the brush for low speed and the cathode of the DC power source to the brush for high speed during ultra-high speed rotation driving. It exists in the wiper motor of Claim 3 characterized by the above-mentioned.
The gist of the invention according to claim 6 of the present invention is that the angle of the installation interval between the low speed brush and the high speed brush is 60 degrees to 80 degrees. The wiper motor according to any one of the above.
The gist of the invention according to claim 7 of the present invention is that the center line of the low-speed brush is inclined by 0 to 20 degrees with respect to the center line of the magnetic flux of the pair of magnets arranged opposite to the motor housing. It exists in the wiper motor as described in any one of Claims 2-6 characterized by the above-mentioned.
The gist of the invention according to claim 8 of the present invention is that the center line of the common brush is inclined at 0 to 20 degrees with respect to the center line of the low-speed brush. It exists in the wiper motor as described in any one of Claims 2-7.
The gist of the invention according to claim 9 of the present invention is a method for switching the number of revolutions of a wiper motor provided with a common brush, a low-speed brush, and a high-speed brush that are in sliding contact with the commutator. Energize the low-speed brush to supply driving power to the armature via the commutator, and energize the common brush and the high-speed brush to drive the armature via the commutator during high-speed rotation driving. And the rotational speed switching method of the wiper motor, wherein the driving power is supplied to the armature through the commutator by energizing the low-speed brush and the high-speed brush during ultra-high speed rotation driving.
The gist of the invention according to claim 10 of the present invention is a method for switching the number of rotations of a wiper motor provided with a common brush, a low-speed brush, and a high-speed brush that are in sliding contact with the commutator. Energize the low-speed brush and supply drive power to the armature via the commutator, drive at 30 to 50 rpm as the rotation speed of the output shaft, and energize the common brush and the high-speed brush during high-speed rotation driving Then, driving power is supplied to the armature through the commutator, and the output shaft is driven at a rotational speed of 50 to 80 rpm, and the ultra-high speed rotational drive is performed by energizing the low-speed brush and the high-speed brush. Drive power is supplied to the armature through a commutator, and the rotational speed of the wiper motor is switched at 100 to 160 rpm as the rotational speed of the output shaft. It resides in the law.
The gist of the invention according to claim 11 of the present invention is that a DC power source is connected to the low-speed brush and the high-speed brush during ultra-high speed rotation driving, and driving power is supplied to the armature via the commutator. The present invention resides in a method for switching the number of revolutions of a wiper motor according to claim 10.
The gist of the invention according to claim 12 of the present invention is characterized in that at the time of ultra high speed rotation driving, a cathode of a DC power source is connected to the low speed brush, and an anode of the DC power source is connected to the high speed brush. The wiper motor rotation speed switching method according to claim 10 or claim 11.
The gist of the invention according to claim 13 of the present invention is that the anode of a DC power source is connected to the low-speed brush and the cathode of the DC power source is connected to the high-speed brush during ultra-high speed rotation driving. The wiper motor rotation speed switching method according to claim 10 or claim 11.
The gist of the invention according to claim 14 of the present invention is that when the wiper arm wiping range is halved, the high speed rotation drive is switched to the ultra high speed rotation drive, and when the wiper arm wiping range is the entire range, the ultra high speed rotation drive is changed to the high speed rotation drive. 14. The wiper motor rotation speed switching method according to claim 10, wherein switching is performed.

  According to the present invention, it is possible to provide a DC wiper motor with a brush that is highly efficient, low in cost, less affected by electromagnetic noise, and capable of changing the rotation speed of the motor in three stages of low speed, high speed, and ultrahigh speed. .

Next, the best mode for carrying out the present invention will be specifically described with reference to the drawings.
In the present invention, the rotational speed of the motor can be varied in three stages: low speed, high speed, and ultra-high speed. In the present invention, low speed and high speed are implemented in the same manner as in the prior art. That is, when driving at low speed, the wiper motor 1 and the DC power supply 30 are connected as shown in FIG. 4, and when driving at high speed, the wiper motor 1 and the DC power supply 30 are connected as shown in FIG. FIG. 6 shows a method of connecting the wiper motor 1 and the DC power source 30 during the ultra-high speed driving of the present invention.

  As shown in FIG. 6, at the time of ultra high speed driving, the high speed brush 23 is connected to the anode 31 of the DC power source 30 and the low speed brush 22 is connected to the cathode (ground) 32 of the DC power source 30. The common brush is not connected to the DC power source 30. When rotating in the direction opposite to the rotating direction when connected as shown in FIG. 6, the low speed brush 22 is connected to the anode 31 of the DC power supply 30 and the high speed brush 23 is connected to the cathode (ground) of the DC power supply 30. It can be implemented by connecting to 32.

Example 1
FIG. 7 shows the brush arrangement employed in Example 1-A. The same reference numerals as those in FIG. 2 denote the same components. The low speed brush 22 is disposed at a position of 180 degrees with respect to the common brush 21, and the high speed brush 23 is disposed with an advance angle of 65 degrees to the right with respect to the low speed brush 22.

  FIG. 8 shows the configuration of the speed switching circuit. In FIG. 8, 1 is a wiper motor, 21 is a common brush, 22 is a brush for low speed, 23 is a brush for high speed, 30 is a DC power supply, 31 is an anode of the DC power supply 30, 32 is a cathode of the DC power supply 30, 41 and 42 are A short-circuit bar 43 (43-1 to 43-17; hereinafter, 43 is collectively referred to as 43-1 to 43-17) is a contact, 44 is a changeover switch, and 45 is a cam.

  The short-circuit bars 41 and 42 move to the stop, low-speed, high-speed, and super-high-speed mode positions to short-circuit the contacts 43. For example, when the short-circuit bars 41 and 42 are in the portion of the super high speed mode indicated by the solid line in FIG. 8, this indicates that the speed mode is currently switched to the super high speed mode, and the contact of this portion 43 is short-circuited. At this time, the portions of the short-circuit bars 41 and 42 indicated by dotted lines indicate that the short-circuit bars 41 and 42 are actually not present, and the contact 43 of this portion is open.

  The connection state when switched to the super high speed mode will be described. The anode 31 of the DC power supply 30 is connected to the high speed brush 23 via the contact 43-17, the shorting bar 42, and the contact 43-16. The cathode 32 of the DC power supply 30 is connected to the low-speed brush 22 via the contact 43-15, the shorting bar 41, and the contact 43-14. Thereby, the connection state for ultra high speed shown in FIG. 6 is realized.

  The connection state when switched to the high speed mode will be described. The anode 31 of the DC power supply 30 is connected to the high speed brush 23 via the contact 43-13, the shorting bar 42, and the contact 43-12. The cathode 32 of the DC power supply 30 is connected to the common brush 21 via the contact 43-11, the shorting bar 41, and the contact 43-10. Thereby, the high-speed connection state shown in FIG. 5 is realized.

  The connection state when switched to the low speed mode will be described. The anode 31 of the DC power supply 30 is connected to the low speed brush 22 via the contact 43-9, the short-circuit bar 42, and the contact 43-8. Further, the cathode 32 of the DC power supply 30 is connected to the common brush 21 via a contact 43-7, a short bar 41, and a contact 43-6. Thereby, the connection state for low speed shown in FIG. 4 is implement | achieved.

  Explaining the connection state when switched to the stop mode, the anode 31 of the DC power supply 30 is connected to the point a of the changeover switch 44 via the contact 43-5, the shorting bar 42, and the contact 43-4. Further, the cathode 32 of the DC power supply 30 is connected to the common brush 21 via the contact 43-3, the shorting bar 41, and the contact 43-1 and is connected via the contact 43-3, the shorting bar 41, and the contact 43-2. Are connected to point b of the changeover switch 44. The point c of the changeover switch 44 is connected to the low speed brush 22. The cam 45 rotates with the rotation of the wiper motor 1 and switches from the contact point a to the point b of the changeover switch 44 at a predetermined rotational position. When the wiper motor 1 is switched from the low-speed mode to the stop mode in such a connection state, the low-speed brush 22 is initially connected to the point a at the point c of the changeover switch because the switch c is connected to the point a. Although connected to the anode 31, when the wiper motor 1 reaches a predetermined rotational position, the contact of the changeover switch is switched from point a to point b and connected to the common brush 21. As a result, the low speed brush 22 and the common brush 21 are short-circuited, and the wiper motor 1 is decelerated and stopped.

  FIG. 9 shows the brush arrangement employed in Example 1-B. The same reference numerals as those in FIG. 2 denote the same components. The low speed brush 22 is disposed at a position of 180 degrees with respect to the common brush 21, and the high speed brush 23 is disposed with an advance angle of 65 degrees to the right with respect to the low speed brush 22. However, the brush arrangement of FIG. 9 is set at a position rotated to the left by 10 degrees as shown in the figure with respect to the brush arrangement of FIG.

  FIG. 10 shows the actually measured motor characteristics of Example 1 (Example 1-A and Example 1-B). In Example 1-A, the no-load rotation speed is 49 rpm left rotation in the low speed mode, 76 rpm left rotation in the high speed mode, and 119 rpm right rotation in the ultra high speed mode. The no-load current, the stalling current, and the stalling torque have values in a continuously operable range. In Example 1-B, the no-load rotational speed is 46 rpm left rotation in the low speed mode, 67 rpm left rotation in the high speed mode, and 138 rpm right rotation in the ultra high speed mode. The no-load current, the stalling current, and the stalling torque have values in a continuously operable range. FIG. 11 is a graph showing actual measurement data of Example 1-A. The target is substantially the third speed switching (the target rotational speed of the output shaft 8 is low speed; 30 rpm to 50 rpm, high speed; 50 rpm to 80 rpm, super high speed; 100 rpm to 160 rpm). FIG. 12 is a graph showing the actual measurement data of Example 1-B, and shows that the target 3-speed switching can be performed in Example 1-B. As for the ultra high speed, the value closer to 150 rpm is obtained in Example 1-B than in Example 1-A.

  FIG. 13 shows another actual measurement example when the high-speed brush 23 is disposed with an advance angle of 65 degrees to the right with respect to the low-speed brush 22. The left 10, left 20, left 30, left 40, right 10, right 15, right 20, right 30 described in “Housing angle (degree)” in the table are the left direction or the right with respect to the brush arrangement of FIG. The angle which rotated the motor housing (magnet) in the direction is shown. Thus, the speed obtained in each speed mode is changed by changing the arrangement relationship between the brush arrangement and the magnet. This result suggests that although there are portions that deviate from the target rotational speed, the target rotational speed can be obtained by adjusting the brush arrangement. However, it also shows that if the brush arrangement is adjusted too much, rotation is impossible.

  FIG. 14 shows another example in which the high-speed brush 23 is arranged with an angle of advance of 65 degrees to the right with respect to the low-speed brush 22, but this brush arrangement is the same as that shown in FIG. On the other hand, the position of the common brush 21 is fixed, and the high speed brush 23 and the low speed brush 22 are rotated 10 degrees to the left. Actual measurement data in this case is not shown, but this brush arrangement is also possible.

(Example 2)
FIG. 15 shows the brush arrangement employed in Example 2-A. The same reference numerals as those in FIG. 2 denote the same components. The low speed brush 22 is arranged at a position of 180 degrees with respect to the common brush 21, and the high speed brush 23 is arranged with an advance angle of 70 degrees to the left with respect to the low speed brush 22. The rotation direction of the armature 13 in this case is opposite to the rotation direction of the first embodiment shown in FIG.

  The configuration of the speed switching circuit is the same as that shown in FIG.

  FIG. 16 shows the brush arrangement employed in Example 2-B. The same reference numerals as those in FIG. 2 denote the same components. The low speed brush 22 is arranged at a position of 180 degrees with respect to the common brush 21, and the high speed brush 23 is arranged with an advance angle of 70 degrees to the left with respect to the low speed brush 22. However, the brush arrangement of FIG. 16 is set at a position rotated to the right by 10 degrees as shown in the figure with respect to the brush arrangement of FIG.

  FIG. 17 shows the motor characteristics of Example 2 (Example 2-A and Example 2-B). In Example 2-A, the no-load rotation speed is 49 rpm in the right direction in the low speed mode, 76 rpm in the right direction in the high speed mode, and 126 rpm in the left direction in the ultra high speed mode. The no-load current, the stalling current, and the stalling torque have values in a continuously operable range. In Example 2-B, the no-load rotational speed is 48 rpm in the right direction in the low speed mode, 69 rpm in the right direction in the high speed mode, and 149 rpm in the left direction in the ultra high speed mode. The no-load current, the stalling current, and the stalling torque have values in a continuously operable range. FIG. 18 is a graph showing the actual measurement data of Example 2-A. The target is substantially the third speed switching (the target rotational speed of the output shaft 8 is low speed: 30 rpm to 50 rpm, high speed; 50 rpm to 80 rpm, super high speed; 100 rpm to 160 rpm). FIG. 19 is a graph showing the actual measurement data of Example 1-B, and shows that the target 3-speed switching can be performed in Example 2-B. As for the ultra high speed, the value closer to 150 rpm is obtained in Example 2-B than in Example 2-A.

  FIG. 20 shows another actual measurement example when the high-speed brush 23 is disposed with an advance angle of 70 degrees to the left with respect to the low-speed brush 22. The left 10, left 20, left 30, right 10, right 20, right 30 described in the “housing angle (degree)” in the table indicate the angle rotated leftward or rightward with respect to the brush arrangement in FIG. Show. Changing the brush arrangement changes the speed obtained in each speed mode. This result suggests that although there are portions that deviate from the target rotational speed, the target rotational speed can be obtained by adjusting the brush arrangement. However, it also shows that if the brush arrangement is adjusted too much, rotation is impossible.

  FIG. 21 shows another example in which the high-speed brush 23 is disposed with an advance angle of 70 degrees to the left with respect to the low-speed brush 22. On the other hand, the position of the common brush 21 is fixed, and the high speed brush 23 and the low speed brush 22 are rotated to the right by 10 degrees. Actual measurement data in this case is not shown, but this brush arrangement is also possible.

(Example 3)
FIG. 22 shows the brush arrangement employed in Example 3-A. The same reference numerals as those in FIG. 2 denote the same components. The low speed brush 22 is disposed at a position of 180 degrees with respect to the common brush 21, and the high speed brush 23 is disposed with an advance angle of 80 degrees to the left with respect to the low speed brush 22. The rotation direction of the wiper motor 1 in this case is the same as the rotation direction of the second embodiment.

  The configuration of the speed switching circuit is the same as that shown in FIG.

  FIG. 23 shows the brush arrangement employed in Example 3-B. The same reference numerals as those in FIG. 2 denote the same components. The low speed brush 22 is disposed at a position of 180 degrees with respect to the common brush 21, and the high speed brush 23 is disposed with an advance angle of 80 degrees to the left with respect to the low speed brush 22. However, the brush arrangement of FIG. 23 is set at a position rotated to the right by 10 degrees as shown in the figure with respect to the brush arrangement of FIG.

  FIG. 24 shows the motor characteristics of Example 3 (Examples 3-A and 3-B, and the case where the brush arrangement is rotated 20 degrees to the left and right). The left 10, left 20, right 10, and right 20 described in the “housing angle (degree)” in the table indicate angles rotated leftward or rightward with respect to the brush arrangement of FIG. In Example 3-A in which the rotation direction of the armature is rightward, the no-load rotation speed is 53 rpm in the low speed mode, 91 rpm in the high speed mode, and 103 rpm in the super high speed mode. In Example 3-B in which the armature rotation direction is the right direction, the no-load rotation speed is 51 rpm in the low speed mode, 79 rpm in the high speed mode, and 106 rpm in the ultra high speed mode. In Example 3-A in which the armature rotation direction is the left direction, the no-load rotation speed is 53 rpm in the low speed mode, 82 rpm in the high speed mode, and 125 rpm in the ultra high speed mode. Further, in Example 3-B in which the rotation direction of the armature is the left direction, the no-load rotation speed is 53 rpm in the low speed mode, 74 rpm in the high speed mode, and 143 rpm in the super high speed mode. In the third embodiment, although the target speed is slightly out of the target speed, the target can be switched to the third speed (the target rotational speed of the output shaft 8 is low speed: 30 rpm to 50 rpm, high speed; 50 rpm to 80 rpm, super high speed; 100 rpm to 160 rpm). It shows that. Further, the speed obtained in each speed mode also changes when the brush arrangement is rotated 20 degrees to the left and right. This result suggests that the brush arrangement can be adjusted so as to obtain the target rotation speed.

  FIG. 25 shows another example when the high-speed brush 23 is disposed with an advance angle of 80 degrees in the right direction with respect to the low-speed brush 22. On the other hand, the position of the common brush 21 is fixed, and the high speed brush 23 and the low speed brush 22 are rotated to the right by 10 degrees. Actual measurement data in this case is not shown, but this brush arrangement is also possible.

The above embodiment of the present invention has the following effects.
(1) It is possible to provide a brushed DC wiper motor that can change the number of rotations of the output shaft 8 of the wiper motor in three stages of low speed (30 rpm to 50 rpm), high speed (50 rpm to 80 rpm), and ultra high speed (100 rpm to 160 rpm). .
(2) The speed control method of the DC motor is not a method of changing the speed by a DC-DC converter or a pulse width modulation (PWM) method, but the speed can be switched by a changeover switch, so that a wiper motor can be provided at a low cost. .
(3) Switching to the ultra-high speed mode does not short-circuit the low-speed brush and the high-speed brush but connects the power source to generate effective torque, so that the efficiency of the wiper motor can be improved.
(4) The speed control method of the direct current motor is not a method of changing the speed by a DC-DC converter or a pulse width modulation (PWM) method, and the speed can be switched by a changeover switch, so that the influence of electromagnetic noise is small.

  Although the embodiments have been specifically described above, the above embodiments are merely examples, and the present invention is of course not limited thereto. Hereinafter, another example of the configuration of the wiper motor will be described.

  When the wiper arm wiping range of the wiper device is halved when the wiper motor is driven at ultra-high speeds, the wiper motor drive force is transmitted from the crankshaft to the wiper arm. It is conceivable to reduce the rotation radius of the crank arm to be halved at the time of ultra-high speed driving.

  Specifically, the crank arm is supported by the support so as to be slidable in the radial direction of the crankshaft, and any one of the pair of engagement members having different crank arm engagement positions with respect to the support is driven by a drive means such as a solenoid. By switching and engaging the crank arm, it is conceivable that the support position of the crank arm by the support is switched and fixed between the longest position where the rotation radius of the crank arm is the longest and the shortest position where the shortest is the shortest.

  An example of the configuration of the wiper motor 1 when used in the wiper device having such a configuration will be described. FIG. 26 is an enlarged view showing the case 3a of the gear portion 3 provided in the wiper motor 1 from the inside. FIG. 27 is a diagram showing an outline of the configuration of the output shaft 8, where (a) is a view from the input end side, (b) is a side view, and (c) is a view from the output end side.

  As shown in FIG. 1, the wiper motor 1 meshes the worm gear 7 included in the rotating shaft 14 and the gear 81 included in the output shaft 8 in the gear portion 3 via the reduction gear 82, and the output shaft 8 is rotated into the rotating shaft 14. It is supposed to be driven. As shown in FIG. 26, a pair of sliders 3a1 is provided on the inner surface of the case 3a included in the gear unit 3. Although not shown in the drawings, wirings that have entered from the outside through through holes formed in the case 3a are connected to the slider 3a1. The wiring is connected to a power source used to supply power to the wiper motor 1 via a switching circuit described later.

  As shown in FIG. 27, on one main surface of the gear 81 facing the output end side of the output shaft 8, a pair of conductive rings 81 a paired with the respective sliders 3 a 1 has an annular shape around the output shaft 8. Presented and arranged. The output shaft 8 is formed with a through hole 8 a extending in the axial direction of the output shaft 8 from the vicinity of the input end to the output end. A wiring for connecting the conductive ring 81a and the driving means outside the case 3a is inserted into the through hole 8a.

  The driving means is, for example, a bistable self-holding solenoid, and slides the shaft in two directions according to the power supply characteristics. When the shaft slides in one direction, one engagement member is biased in a direction to engage with the crank arm, and the other engagement member is biased in a direction to release the engagement with the crank arm. The engaging member is biased in the reverse direction.

  Next, the configuration of the switching circuit for switching the power supply to the wiper motor 1 and the solenoid will be described. FIG. 28 shows the configuration of the switching circuit. The switching circuit shown in FIG. 28 has substantially the same configuration as the speed switching circuit shown in FIG. 8, but the terminals 43-20 to 43-27 for connection to the solenoid are connected to the contacts 43-1 to 43-1 described above. In addition to 43-17.

  When switching from the high speed mode to the ultra high speed mode, first, the shorting bar 41 is switched from the contacts 43-10 and 11 to the contacts 43-20 and 21, and the shorting bar 42 is switched from the contacts 43-12 and 13 to the contacts 43-22. 23 to be connected to each other.

  At this time, the anode 31 of the DC power supply 30 is connected to one terminal of the solenoid (S) through the contact 43-23, the shorting bar 42, and the contact 43-22. Further, the cathode 32 of the DC power supply 30 is connected to the other terminal of the solenoid through the contact 43-21, the shorting bar 41, and the contact 43-20.

  In this connection state, the solenoid operates in the same direction as when shifting to the high speed mode, and one engagement member is kept engaged with the crank arm. Next, the shorting bar 41 is switched and connected to the contacts 43-24 and 25, and the shorting bar 42 is switched to the contacts 43-26 and 27, respectively.

  At this time, the anode 31 of the DC power supply 30 is connected to the other terminal of the solenoid through the contact 43-27, the short-circuit bar 42, and the contact 43-26. Further, the cathode 32 of the DC power supply 30 is connected to one terminal of the solenoid through the contact 43-25, the shorting bar 41, and the contact 43-24.

  When this connection state is realized, the solenoid operates to disengage one engagement member from the crank arm. As a result, the crank arm rotating in the high speed mode slides with respect to the support, and the other engaging member engages with the crank arm. As a result, the support position of the crank arm by the support is changed from the longest position to the shortest position, and the wiping range of the wiper arm is halved.

  Thereafter, the short-circuit bar 41 is switched and connected from the contacts 43-24 and 25 to the contacts 43-14 and 15 and the short-circuit bar 42 is switched from the contacts 43-26 and 27 to the contacts 43-16 and 17, respectively. Transition to high-speed mode.

  When the wiper motor 1 is switched from the ultra high speed mode to the high speed mode, the shorting bar 41 is contacted from the contacts 43-14, 15 to the contacts 43-24, 25, and the shorting bar 42 is contacted from the contacts 43-16, 17 to the contact 43- 26 and 27 are switched and connected.

  At this time, the anode 31 of the DC power supply 30 is connected to the other terminal of the solenoid through the contact 43-27, the short-circuit bar 42, and the contact 43-26. Further, the cathode 32 of the DC power supply 30 is connected to one terminal of the solenoid through the contact 43-25, the shorting bar 41, and the contact 43-24.

  In this connection state, the solenoid operates in the same direction as when shifting to the ultra high speed mode, and the other engagement member is kept engaged with the crank arm. Next, the shorting bar 41 is switched and connected to the contacts 43-20 and 21 and the shorting bar 42 is switched to the contacts 43-22 and 23, respectively.

  At this time, the anode 31 of the DC power supply 30 is connected to one terminal of the solenoid through the contact 43-23, the shorting bar 42, and the contact 43-22. Further, the cathode 32 of the DC power supply 30 is connected to the other terminal of the solenoid through the contact 43-21, the shorting bar 41, and the contact 43-20.

  When this connection state is realized, the solenoid operates in the direction opposite to that at the time of transition to the ultra high speed mode, and the engagement of the other engagement member with the crank arm is released. As a result, the crank arm rotating in the high speed mode slides with respect to the support, and one of the engaging members engages with the crank arm. As a result, the support position of the crank arm by the support is changed from the shortest position to the longest position, and the wiping range of the wiper arm becomes the entire range.

  Thereafter, the shorting bar 41 is switched from the contacts 43-20 and 21 to the contacts 43-10 and 11, and the shorting bar 42 is switched from the contacts 43-22 and 23 to the contacts 43-12 and 13, respectively. Enter mode.

  According to the wiper motor 1 having the above-described configuration, even if the configuration in which the solenoid and the engaging member are rotated integrally with the crank arm and the support body is employed, the power supply wiring is provided so as not to be affected by this rotation. Can be routed to the solenoid.

It is sectional drawing which shows an example of the wiper motor structure of a prior art. It is a figure which shows the brush arrangement | positioning in the 2-speed switching wiper motor of a prior art (AA sectional drawing of FIG. 1). It is a figure which shows the magnet arrangement | positioning in the 2-speed switching wiper motor of a prior art (BB sectional drawing of FIG. 1). It is a figure explaining the power supply connection state when the wiper motor of the prior art is switched to the low speed mode. It is a figure explaining the power supply connection state when the wiper motor of the prior art is switched to the high speed mode. It is a figure explaining the power supply connection state when switched to the ultra high-speed mode by this invention. It is a figure which shows the brush arrangement | positioning of Example 1-A of this invention. It is the figure which showed the 3rd speed switching circuit of this invention. It is a figure which shows the brush arrangement | positioning of Example 1-B of this invention. It is a figure which shows the motor characteristic (measured value) of Example 1 (Example 1-A, Example 1-B) of this invention. It is a figure which shows the motor characteristic (measured value) of Example 1 (Example 1-A) of this invention with a graph. It is a figure which shows the motor characteristic (measured value) of Example 1 (Example 1-B) of this invention with a graph. It is a figure which shows the motor characteristic (measured value) of Example 1 (Example 1-A, Example 1-B, others) of this invention. It is a figure which shows other brush arrangement | positioning in Example 1 of this invention. It is a figure which shows the brush arrangement | positioning of Example 2-A of this invention. It is a figure which shows the brush arrangement | positioning of Example 2-B of this invention. It is a figure which shows the motor characteristic (measured value) of Example 2 (Example 2-A, Example 2-B) of this invention. It is a figure which shows the motor characteristic (measured value) of Example 2 (Example 2-A) of this invention with a graph. It is a figure which shows the motor characteristic (measured value) of Example 2 (Example 2-B) of this invention with a graph. It is a figure which shows the motor characteristic (measured value) of Example 2 (Example 2-A, Example 2-B, others) of this invention. It is a figure which shows the other brush arrangement | positioning in Example 2 of this invention. It is a figure which shows the brush arrangement | positioning of Example 3-A of this invention. It is a figure which shows the brush arrangement | positioning of Example 3-B of this invention. It is a figure which shows the motor characteristic (measured value) of Example 3 (Example 3-A, Example 3-B, others) of this invention. It is a figure which shows the other brush arrangement | positioning in Example 3 of this invention. It is a figure which expands and shows the case of the gear part with which a wiper motor is provided from the inner side. It is a figure which shows the outline of a structure of the output shaft with which a wiper motor is provided, (a) is the input end side, (b) is a side, (c) is the figure seen from the output end side. 2 shows a configuration of a power supply switching circuit in a driving means and a wiper motor provided in the wiper device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Wiper motor 2 ... Motor part 3 ... Gear part 3a ... Case 3a1 ... Slider 4 ... Gear case flange 5, 6 ... Bearing 7 ... Worm gear 8 ... Output shaft 8a ... through hole 81 ... gear 81a ... conductive ring 11 ... motor housing 12 ... magnet 13 ... armature 14 ... rotary shaft 16 ... commutator 20 ... Brush device 21 ... Common brush 22 ... Low speed brush 23 ... High speed brush 24, 25, 26 ... Brush holder 30 ... DC power supply 31 ... Anode 32 ... Cathode (ground)
41, 42 ... short-circuit bar 43 (43-1 to 43-17, 43-20 to 43-27) ... contact 44 ... changeover switch 45 ... cam

Claims (14)

A common brush, a low speed brush, and a high speed brush that are in sliding contact with the commutator are provided, and at the time of low speed rotation driving, the common brush and the low speed brush are energized to supply drive power to the armature through the commutator, In a wiper motor comprising switching means for supplying a driving power to the armature through the commutator by energizing the common brush and the high-speed brush during high-speed rotation driving,
The wiper motor according to claim 1, wherein the switching means performs switching so that the low-speed brush and the high-speed brush are energized to supply driving power to the armature via the commutator during ultra-high speed rotation driving. A common brush, a low speed brush, and a high speed brush that are in sliding contact with the commutator are provided, and at the time of low speed rotation driving, the common brush and the low speed brush are energized to supply drive power to the armature through the commutator, The rotation speed of the output shaft is driven at 30 to 50 rpm, and at the time of high-speed rotation drive, the common brush and the high-speed brush are energized to supply drive power to the armature via the commutator, and the rotation speed of the output shaft As a wiper motor driven at 50 to 80 rpm,
When driving at ultra-high speed, the low-speed brush and the high-speed brush are energized to supply drive power to the armature via the commutator, and the output shaft is driven at a rotational speed of 100 to 160 rpm. Wiper motor.   3. A switching means for connecting a DC power source to the low-speed brush and the high-speed brush and driving power to the armature via the commutator during ultra-high speed rotation driving. Wiper motor.   4. The wiper motor according to claim 3, wherein the switching unit connects a cathode of a DC power source to the low-speed brush and an anode of the DC power source to the high-speed brush during ultra-high speed rotation driving.   4. The wiper motor according to claim 3, wherein the switching means connects the anode of a DC power source to the low-speed brush and the cathode of the DC power source to the high-speed brush during ultra-high speed rotation driving.   The wiper motor according to any one of claims 2 to 5, wherein an angle of an installation interval between the low-speed brush and the high-speed brush is 60 degrees to 80 degrees.   The center line of the low-speed brush is provided so as to be inclined by 0 to 20 degrees with respect to the center line of the magnetic flux of a pair of magnets arranged opposite to the motor housing. The wiper motor according to claim 6.   The wiper motor according to any one of claims 2 to 7, wherein a center line of the common brush is inclined by 0 to 20 degrees with respect to a center line of the low-speed brush. . In a method for switching the number of rotations of a wiper motor provided with a common brush, a low speed brush, and a high speed brush that are in sliding contact with the commutator,
When driving at low speed, the common brush and the low speed brush are energized to supply driving power to the armature through the commutator,
When driving at high speed, the common brush and the high speed brush are energized to supply driving power to the armature through the commutator,
A method for switching the number of revolutions of a wiper motor, wherein the driving power is supplied to the armature through the commutator by energizing the low-speed brush and the high-speed brush during ultra-high speed rotation driving. In a method for switching the number of rotations of a wiper motor provided with a common brush, a low speed brush, and a high speed brush that are in sliding contact with the commutator,
At the time of low-speed rotation driving, the common brush and the low-speed brush are energized to supply driving power to the armature via the commutator, and driven at 30 to 50 rpm as the rotation speed of the output shaft,
At the time of high-speed rotation drive, the common brush and the high-speed brush are energized to supply drive power to the armature through the commutator, and the output shaft is driven at 50 to 80 rpm,
When driving at ultra-high speed, the low-speed brush and the high-speed brush are energized to supply drive power to the armature via the commutator, and the output shaft is driven at a rotational speed of 100 to 160 rpm. How to change the rotation speed of the wiper motor.   The rotational speed of the wiper motor according to claim 10, wherein a DC power source is connected to the low-speed brush and the high-speed brush during ultra-high-speed rotation driving, and driving power is supplied to the armature through the commutator. Switching method.   12. The method for switching the number of revolutions of a wiper motor according to claim 10, wherein a cathode of a DC power source is connected to the low-speed brush and an anode of the DC power source is connected to the high-speed brush during ultra-high speed rotation driving.   12. The method for switching the number of revolutions of a wiper motor according to claim 10, wherein an anode of a DC power source is connected to the low-speed brush and a cathode of the DC power source is connected to the high-speed brush during ultra-high speed rotation driving. When the wiper arm wiping range is halved, switch from high-speed rotation to ultra-high-speed rotation.
14. The wiper motor rotation speed switching method according to any one of claims 10 to 13, wherein the wiper arm wiping range is switched from the ultra-high speed rotation drive to the high speed rotation drive when the entire range is wiped.

Images