JP2018149919A - Wiper device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wiper device capable of improving the torque of an output shaft of a wiper motor and preventing the wiper motor from being overloaded. When the target rotation speeds of the wiper motors 18 and 20 are low, the wiper ECUs 60B and 62B apply a voltage generated by pulse width modulation to the coils of the wiper motors 18 and 20 at a timing corresponding to the rotation position of the rotor. The drive circuits 60A and 62A are controlled so that the first rotation control is performed, and when the target rotation speed is high, the wiper motors 18 and 20 coils are pulsed at the timing advanced by the electric angle from the timing of the first rotation control. The second rotation control that starts energization of the voltage generated without width modulation and ends the energization of the coils of the wiper motors 18 and 20 at the timing retarded by the electric angle from the timing of the end of energization of the first rotation control is performed. The drive circuits 60A and 60B are controlled so as to be used. [Selection diagram] Fig. 1

Description

  The present invention relates to a wiper device.

  In the wiper device, the wiper blade can be wiped at a low speed and can be wiped at a high speed. When the wiper blade is wiped at a low speed, the rotation speed of the wiper motor is lowered. When the wiper blade is wiped at a high speed, the rotation speed of the wiper motor is increased.

  A brushless DC motor using a permanent magnet for the rotor (rotor) and an electromagnet (coil) for the stator (stator) may be used for the wiper motor. When the voltage applied to the coil increases, the rotational speed of the rotor increases, but the torque of the output shaft provided at the center of the rotor has a property of decreasing.

  FIG. 12 is an explanatory diagram showing the rotation speed of the output shaft relative to the torque of the output shaft in the brushless DC motor. A straight line 92 in FIG. 12 indicates the rotation speed of the output shaft with respect to the torque of the output shaft of the wiper motor when the wiper blade is wiped at a high speed, and a straight line 94 in FIG. 12 indicates the wiper motor when the wiper blade is wiped at a low speed. The rotational speed of the output shaft with respect to the torque of the output shaft is shown. As indicated by a straight line 96 indicating the relationship between the straight output shaft torque and the output shaft rotation speed, the output shaft rotation speed decreases as the output shaft torque increases.

  In the output of the motor, the torque and the rotational speed are in a trade-off relationship. When the rotational speed of the output shaft is increased, the torque of the output shaft decreases, and when the torque of the output shaft is increased, the rotational speed of the output shaft decreases. As shown by the straight line 92, if the output shaft of the wiper motor is rotated at high speed, the torque cannot be improved. As shown by the straight line 94, if the torque of the output shaft of the wiper motor is increased, it is difficult to improve the rotational speed. .

  In order to cover the characteristics indicated by the straight lines 92 and 94 in FIG. 12 with one motor, it is necessary to rotate the output shaft of the motor at the torque and rotational speed indicated by the straight line 96. However, a motor capable of realizing a large torque and high rotation as shown by the straight line 96 needs to have a large rating, and as a result, the motor body must be heavy and large, and further, the cost is high. There was a problem.

  In Patent Document 1, when the wiping speed is low, the motor coil is energized at an electrical angle of 120 degrees, and when the wiping operation is high speed, the energization timing is advanced by 30 degrees as compared with the case of low speed. In addition, a wiper device is disclosed that energizes a motor coil with an electrical angle of 135 to 165 degrees.

International Publication No. 2015/098789

  The technique disclosed in Patent Document 1 rotates the output shaft of the motor at high speed and high torque by advancing the energization timing and extending the energization time when the wiping speed is high. However, the technique disclosed in Patent Document 1 cannot be said that the advance angle of the energization timing and the extension of the energization time are sufficient, for example, when an obstacle such as a snow pool exists on the windshield glass, There is a problem that it is difficult to realize an output sufficient to eliminate an obstacle by the wiper blade wiping operation.

  The present invention has been made in view of the above, and an object thereof is to provide a wiper device that improves both the rotational speed and torque of the output shaft of a wiper motor.

  In order to solve the above-mentioned problem, the wiper device according to claim 1 includes a rotor and a coil that generates a rotating magnetic field, and rotationally drives a wiper motor that wipes the wiper blade by rotating the rotor according to the rotating magnetic field. When the drive unit and the command value are the first reference rotational speed, a voltage generated by pulse width modulation is supplied to the coil at a timing corresponding to the rotational position of the rotor, and the rotational speed of the wiper motor is The drive unit is controlled so that the first rotation control for controlling to the first reference rotation speed is performed. If the command value is the second reference rotation speed faster than the first reference rotation speed, the energization is started from the start of energization. Energization is started at a timing at which the voltage generated so as to be continuously energized until the end is advanced by an electrical angle from the energization start timing of the first rotation control. A control unit that controls the driving unit so that the second rotation control for controlling the rotation speed of the wiper motor to the second reference rotation speed is performed by stopping energization at a timing delayed by an electrical angle from the end timing of power generation. And.

  According to this wiper device, energization of the voltage generated without pulse width modulation to the coil is started at a timing advanced by an electrical angle from the timing of the first rotation control, and the electric current is started from the timing of the end of energization of the first rotation control. By performing the second rotation control that ends energization of the coil at the timing delayed by the angle, both the rotational speed and torque of the output shaft of the wiper motor can be improved.

  The wiper device according to a second aspect is the wiper device according to the first aspect, wherein the control unit starts from energization when the command value is a third reference rotational speed that is faster than the second reference rotational speed. Energization is started at a timing advanced by an electrical angle from the energization start timing of the second rotation control at a voltage generated so as to continue energization until the end of energization, and at substantially the same timing as the energization end timing of the first rotation control. The third rotation control for controlling the rotation speed of the wiper motor to the third reference rotation speed by energizing and expanding the energization section from the start of energization to the end of energization beyond the energization section of the second rotation control is performed. The driving unit is controlled as shown in FIG.

  According to this wiper device, energization of the voltage generated without pulse width modulation to the coil is started at a timing advanced by an electrical angle from the timing of the second rotation control, and at the same timing as the energization end timing of the first rotation control. In step 3, the rotation speed and torque of the output shaft of the wiper motor are further increased by performing the third rotation control in which the energization section from the start of energization to the end of energization is expanded beyond the energization section of the second rotation control. Can be improved.

  The wiper device according to a third aspect is the wiper device according to the second aspect, wherein the control unit starts from energization when the command value is a fourth reference rotational speed that is faster than the third reference rotational speed. The voltage generated so as to be continuously energized until the end of energization starts energization at a timing advanced by an electrical angle from the energization start timing of the third rotation control, and advances by an electrical angle from the energization end timing of the first rotation control. Energization is terminated at an angled timing, the energization section from the start of energization to the end of energization is expanded beyond the energization section of the second rotation control, and the rotation speed of the wiper motor is controlled to the fourth reference rotation speed. The drive unit is controlled so that rotation control is performed.

  According to this wiper device, energization of a voltage generated without pulse width modulation to the coil is started at a timing advanced by an electrical angle from the timing of the third rotation control, and at the electrical angle from the timing of the end of energization of the first rotation control. By energizing the coil at the timing advanced at, and performing the fourth rotation control in which the energization section from the start of energization to the end of energization is expanded beyond the energization section of the second rotation control, the output shaft of the wiper motor The rotational speed and torque can be further improved.

  The wiper device according to a fourth aspect is the wiper device according to the third aspect, wherein the control unit is configured to perform the first operation when a duty ratio of pulse width modulation calculated according to the command value is less than 100%. The rotation control is performed, and the second rotation control is started when the duty ratio calculated according to the command value reaches 100%. Thereafter, the second rotation control, the second rotation control according to the command value, and the second rotation control. One of the three rotation control and the fourth rotation control is performed.

  According to this wiper device, the second rotation control is started when the duty ratio reaches 100%, and thereafter any one of the second rotation control, the third rotation control, and the fourth rotation control is performed according to the command value. By doing so, the rotational speed and torque of the output shaft of the wiper motor can be controlled according to the command value.

It is the schematic which shows the structure of the wiper apparatus which concerns on embodiment of this invention. It is a block diagram which shows the outline of an example of a structure of the wiper control circuit of the right wiper apparatus which concerns on embodiment of this invention. (A) is explanatory drawing which showed an example of the alternating current primary component contained in rectangular wave energization with the electrical angle of 120 degrees generally performed with synchronous motors, such as a brushless DC motor, (B) is an electrical angle. It is explanatory drawing which showed an example of the alternating current primary component contained in the rectangular wave energization at 180 degree | times. It is explanatory drawing which showed the rotational speed of the output shaft with respect to the torque of the output shaft in a wiper motor. It is explanatory drawing which showed the rotational speed of the output shaft with respect to the torque of the output shaft in a wiper motor. It is explanatory drawing which showed an example of the process which changes the duty ratio of the voltage which supplies with electricity to a coil, (A) is a case where a duty ratio is low, (B) is a case where a duty ratio is medium, (C) Indicates the case where the duty ratio is 100%, which is the highest. It is explanatory drawing which showed an example of the process of changing an energization width after setting the duty ratio of the voltage energized to a coil to 100%, (A) is a case where the energization width is 120 degrees, (B) is an energization width. (C) shows the case where the energization width is enlarged to nearly 180 degrees, respectively, in the case of enlarging in the range of 120 degrees to less than 180 degrees. It is explanatory drawing which showed an example of the process of changing an energization timing after energizing width is expanded to near 180 degree | times, (A) is a case where an energization timing is not advanced, (B) is an energization timing from 0 degree | times. (C) shows the case where the advance angle is advanced to near 60 degrees when the angle is advanced within a range of less than 60 degrees. (A) is a time chart showing an example of the energization pattern to the coil when the energization timing is not advanced at an energization width of 120 degrees, and (B) is an advancement of the energization timing at an energization width of approximately 180 degrees. It is the time chart which showed an example of the electricity supply pattern to the coil in the case. (A) is an explanatory view showing an example of a change in energization width when the wiper blade is wiped at a high speed from the lower inversion position to the upper inversion position, and (B) is an upper view of the wiper blade from the lower inversion position. It is explanatory drawing which showed an example of the change of the duty ratio of the voltage applied to the wiper motor in the case of making a wiping operation | movement to a reverse position at high speed. It is the flowchart which showed an example of the energization width and advance angle control in the wiper apparatus which concerns on embodiment of this invention. It is explanatory drawing which showed the rotational speed of the output shaft with respect to the torque of the output shaft in a brushless DC motor.

  FIG. 1 is a schematic diagram illustrating a configuration of a wiper device 10 according to the present embodiment. For example, the wiper device 10 includes a left wiper device 14 on the left (passenger seat side) of the lower portion of the windshield glass 12 of the vehicle and a right wiper device 16 on the right (driver's seat side) of the lower portion of the windshield glass 12 of the vehicle. It is a tandem wiper device with direct drive provided. The left and right in the present embodiment are the left and right as viewed from the passenger compartment. The wiper device 10 according to the present embodiment rotates the wiper arm 26 of the left wiper device 14 and the wiper arm 28 of the right wiper device 16 in the same direction. Therefore, the output shaft 36 of the left wiper device 14 and the output shaft 38 of the right wiper device 16 are each rotated in the same direction.

  The left wiper device 14 and the right wiper device 16 include wiper motors 18 and 20, speed reduction mechanisms 22 and 24, wiper arms 26 and 28, and wiper blades 30 and 32, respectively. The wiper motors 18 and 20 are provided on the lower left and lower right of the windshield glass 12, respectively.

  In the left wiper device 14 and the right wiper device 16, the forward and reverse rotations of the wiper motors 18 and 20 are respectively decelerated by the speed reduction mechanisms 22 and 24, and the output shafts 36 and 38 are respectively rotated by the forward and reverse rotations decelerated by the speed reduction mechanisms 22 and 24. Rotate. Further, the rotational forces of the forward and reverse rotations of the output shafts 36 and 38 act on the wiper arms 26 and 28, respectively, so that the wiper arms 26 and 28 move from the storage position P3 to the lower inversion position P2, and the lower inversion position P2 and the upper inversion position. It reciprocates between P1. By the operation of the wiper arms 26 and 28, the wiper blades 30 and 32 respectively provided at the tips of the wiper arms 26 and 28 wipe between the lower inversion position P2 and the upper inversion position P1 on the surface of the windshield glass 12. The speed reduction mechanisms 22 and 24 are constituted by, for example, worm gears, and reduce the rotations of the wiper motors 18 and 20 to rotation speeds suitable for wiping the surface of the windshield glass 12 by the wiper blades 30 and 32, respectively. To rotate the output shafts 36 and 38 respectively.

  As described above, the wiper motors 18 and 20 according to the present embodiment have the speed reduction mechanisms 22 and 24 each composed of a worm gear. Therefore, the rotation speed and rotation angle of the output shafts 36 and 38 are determined by the wiper motor 18. , 20 is not the same as the rotation speed and rotation angle of the main body. However, in the present embodiment, since the wiper motors 18 and 20 and the speed reduction mechanisms 22 and 24 are inseparably configured, the rotational speeds and rotation angles of the output shafts 36 and 38 are hereinafter referred to as the wiper motors 18 and 20, respectively. The rotation speed and rotation angle are considered. In the present embodiment, for example, by synchronizing the rotation direction of the output shaft 36 of the left wiper device 14 with the rotation direction of the output shaft 38 of the right wiper device 16, the output shaft 36 and the output shaft 38 are respectively in the same direction. It is rotating.

  Wiper control circuits 60 and 62 for controlling the rotation of the wiper motors 18 and 20 are connected to the wiper motors 18 and 20, respectively. The wiper control circuit 60 according to the present embodiment includes a drive circuit 60A and a wiper ECU 60B, and the wiper control circuit 62 includes a drive circuit 62A and a wiper ECU 62B.

  A rotation angle sensor 42 that detects the rotation speed and rotation angle of the output shaft 36 of the wiper motor 18 is connected to the wiper ECU 60B. A rotation angle sensor 44 that detects the rotation speed and rotation angle of the output shaft 38 of the wiper motor 20 is connected to the wiper ECU 62B. The wiper ECUs 60B and 62B calculate the positions of the wiper blades 30 and 32 on the windshield glass 12 based on the signals from the rotation angle sensors 42 and 44, respectively. The wiper ECUs 60B and 62B control the drive circuits 60A and 62A so that the rotation speeds of the output shafts 36 and 38 change according to the calculated positions. The rotation angle sensors 42 and 44 are provided in the speed reduction mechanisms 22 and 24 of the wiper motors 18 and 20, respectively, and convert the magnetic field (magnetic force) of the excitation coil or magnet that rotates in conjunction with the output shafts 36 and 38 into current. To detect. The rotational speed of the output shafts 36 and 38 is controlled by a speed map (not shown) that defines the rotational speeds of the output shafts 36 and 38 according to the positions of the wiper blades 30 and 32, which is stored in a memory or the like described later. ).

  The drive circuits 60A and 62A generate voltages (currents) for operating the wiper motors 18 and 20, respectively, by PWM (Pulse Width Modulation) control and supply them to the wiper motors 18 and 20, respectively. The drive circuits 60A and 62A include a circuit using a field effect transistor (MOSFET) as a switching element. The drive circuit 60A is a wiper ECU 60B, and the drive circuit 62A is a wiper ECU 62B. Is output.

  The wiper ECU 60B and the wiper ECU 62B synchronize the operations of the left wiper device 14 and the right wiper device 16 by, for example, linking with communication using a protocol such as LIN (Local Interconnect Network). A wiper switch 66 is connected to the wiper ECU 62 </ b> B of the wiper control circuit 62 via the vehicle control circuit 64.

  The wiper switch 66 is a switch for turning on or off the electric power supplied from the vehicle battery to the wiper motors 18 and 20. The wiper switch 66 includes a low speed operation mode selection position for operating the wiper blades 30 and 32 at a low speed, a high speed operation mode selection position for operating at a high speed, an intermittent operation mode selection position for intermittent operation at a constant period, and a stop mode selection position. Can be switched to. Further, a command signal for rotating the wiper motors 18 and 20 according to the selected position in each mode is output to the wiper ECU 62B via the vehicle control circuit 64. The command signal input to the wiper ECU 62B is also input to the wiper ECU 60B by communication using the protocol such as the LIN described above. In FIG. 1, for the sake of convenience, the right wiper device 16 is a master wiper and the left wiper device 14 is a slave wiper.

  When signals output from the wiper switch 66 according to the selected position of each mode are input to the wiper ECUs 60B and 62B, the wiper ECUs 60B and 62B perform control corresponding to the output signals from the wiper switch 66. Specifically, the wiper ECUs 60B and 62B calculate the rotational speeds of the output shafts 36 and 38 based on the command signal from the wiper switch 66 and the above-described speed map. Further, the wiper ECUs 60B and 62B control the drive circuits 60A and 62A so that the output shafts 36 and 38 rotate at the calculated rotational speed.

  FIG. 2 is a block diagram schematically illustrating an example of the configuration of the wiper control circuit 62 of the right wiper device 16 according to the present embodiment. Moreover, the wiper motor 20 shown in FIG. 2 is a brushless DC motor as an example. The configuration of the wiper control circuit 60 of the left wiper device 14 is the same as that of the wiper control circuit 62 of the right wiper device 16, and thus detailed description thereof is omitted.

  The wiper control circuit 62 shown in FIG. 2 includes a drive circuit 62A that generates a voltage to be applied to terminals of the coils 40U, 40V, and 40W of the stator (stator 40) of the wiper motor 20, and switching elements that constitute the drive circuit 62A. And a wiper ECU 62B for controlling on and off.

  The rotor 72 of the wiper motor 20 is composed of three S-pole and N-pole permanent magnets, respectively, and is configured to rotate following the rotating magnetic field generated in the coils 40U, 40V, and 40W of the stator 40. . The magnetic field of the rotor 72 is detected by the hall sensor 70. The Hall sensor 70 may detect a magnetic field of a sensor magnet provided separately from the rotor 72 corresponding to the polarity of the permanent magnet of the rotor 72. The hall sensor 70 detects the magnetic field of the rotor 72 or the sensor magnet as a magnetic field indicating the position of the rotor 72.

  The hall sensor 70 is a sensor for detecting the position of the rotor 72 by detecting a magnetic field formed by the rotor 72 or a sensor magnet. The hall sensor 70 includes three hall elements corresponding to U, V, and W phases. The Hall sensor 70 outputs a change in magnetic field generated by the rotation of the rotor 72 as a voltage change signal approximating a sine wave.

  The signal output from the hall sensor 70 is input to the wiper ECU 62B which is a control circuit. The wiper ECU 62B is an integrated circuit, and the power supplied from the battery 80 as a power source is controlled by the standby circuit 50.

  The analog waveform signal input from the hall sensor 70 to the wiper ECU 62B is input to the hall sensor edge detection unit 56 including a circuit for converting an analog signal such as a comparator into a digital signal in the wiper ECU 62B. The hall sensor edge detector 56 converts the input analog waveform into a digital waveform, and detects an edge portion from the digital waveform.

  The digital waveform and edge information are input to the motor position estimation unit 54, and the position of the rotor 72 is calculated. Information on the calculated position of the rotor 72 is input to the energization control unit 58.

  A signal for instructing the rotational speed of the wiper motor 20 (rotor 72) is input from the wiper switch 66 to the command value calculation unit 52 of the wiper ECU 62B. The command value calculation unit 52 extracts a command related to the rotation speed of the wiper motor 20 from the signal input from the wiper switch 66 and inputs the command to the energization control unit 58.

  The energization control unit 58 calculates the phase of the voltage that changes according to the magnetic pole position of the rotor 72 calculated by the motor position estimation unit 54, and also calculates the calculated phase and the rotation speed of the rotor 72 indicated by the wiper switch 66. The driving duty value is determined based on the above. The energization control unit 58 performs PWM control that generates a PWM signal that is a pulse signal corresponding to the drive duty value and outputs the PWM signal to the drive circuit 62A. By the PWM control, the drive circuit 62A generates a voltage that changes at a timing based on the position of the magnetic pole of the rotor 72 and applies the voltage to the coils 40U, 40V, and 40W of the stator 40. A rotating magnetic field that rotates the rotor 72 is generated in the coils 40U, 40V, and 40W to which the voltage is applied.

  The drive circuit 62A is configured by a three-phase (U phase, V phase, W phase) inverter. As shown in FIG. 2, the drive circuit 62A includes three N-channel field effect transistors (MOSFETs) 74U, 74V, and 74W (hereinafter referred to as “FETs 74U, 74V, and 74W”) each serving as an upper stage switching element. Three N-channel field effect transistors 76U, 76V, 76W (hereinafter referred to as “FETs 76U, 76V, 76W”) as lower-stage switching elements are provided. The FETs 74U, 74V, and 74W and the FETs 76U, 76V, and 76W are collectively referred to as “FET74” and “FET76” when they do not need to be distinguished from each other, and “U” when they need to be distinguished from each other. , “V”, “W” are attached with symbols.

  Among the FETs 74 and 76, the source of the FET 74U and the drain of the FET 76U are connected to the terminal of the coil 40U, the source of the FET 74V and the drain of the FET 76V are connected to the terminal of the coil 40V, the source of the FET 74W and the FET 76W. The drain is connected to the terminal of the coil 40W.

  The gates of the FET 74 and the FET 76 are connected to the energization control unit 58, and a PWM signal is input. The FET 74 and FET 76 are turned on when an H level PWM signal is input to the gate, and current flows from the drain to the source. Further, when an L level PWM signal is input to the gate, the transistor is turned off and no current flows from the drain to the source.

  Further, the wiper control circuit 62 of the present embodiment includes a battery 80, a noise prevention coil 82, smoothing capacitors 84A and 84B, and the like. The battery 80, the noise prevention coil 82, and the smoothing capacitors 84A and 84B constitute a substantially DC power source.

  Further, on the substrate of the wiper control circuit 62 of the present embodiment, a chip thermistor RT is applied with a control voltage Vcc applied to one end via a resistor R1 and the other end grounded to detect the temperature of the substrate as a resistance value. Has been implemented. The chip thermistor RT used in this embodiment is an NTC (Negative Temperature Coefficient) thermistor whose resistance decreases with increasing temperature, and the resistance value of the chip thermistor RT decreases with increasing temperature. Note that a PTC (Positive Temperature Coefficient) thermistor whose resistance value increases as the temperature rises by using an inverting circuit together may be used.

  The chip thermistor RT and the resistor R1 form a kind of voltage dividing circuit, and a voltage that changes based on the resistance value of the chip thermistor RT is output from one end of the chip thermistor RT connected to the resistor R1. . The voltage output from one end of the chip thermistor RT is compared with the overheat determination value in the energization control unit 58, and when the voltage output from one end of the chip thermistor RT is equal to or lower than the overheat determination value, the wiper control circuit 62 is in an overheat state. It is determined that As described above, since the chip thermistor RT according to the present embodiment is a type in which the resistance decreases as the temperature rises, the chip thermistor that is also the output terminal of the voltage dividing circuit composed of the resistor R1 and the chip thermistor RT. The voltage output from one end of RT decreases as the temperature increases. The energization control unit 58 determines that the circuit is overheated when the voltage output from one end of the chip thermistor RT is equal to or lower than the overheat determination value. The overheat determination value varies depending on the element mounted on the substrate, the position of the chip thermistor RT, and the like. As an example, the overheat determination value is a voltage output from the voltage dividing circuit of the chip thermistor RT and the resistor R1 at 145 ° C.

  In addition, a current detection unit 68 is provided between each source of the FETs 76U, 76V, and 76W and the battery 80. The current detector 68 includes a shunt resistor having a resistance value of about 0.2 mΩ to several Ω, and an amplifier that amplifies a potential difference between both ends of the shunt resistor and outputs a voltage value proportional to the current of the shunt resistor as a signal. The signal output from the amplifier is input to the energization control unit 58. The energization control unit 58 compares the signal output from the current detection unit 68 with the overcurrent determination value, and determines that the motor current is overcurrent when the signal output from the current detection unit 68 is equal to or greater than the overcurrent determination value. To do. Although not shown in FIG. 2, a voltage sensor or the like for detecting the voltage of the battery 80 is mounted on the substrates of the wiper control circuits 60 and 62.

  Hereinafter, an operation and effect of wiper device 10 concerning this embodiment is explained. FIG. 3A is an explanatory diagram showing an example of an AC primary component 86B included in a rectangular wave energization 86A at an electrical angle of 120 degrees, which is generally performed in a synchronous motor such as a brushless DC motor. B) is an explanatory diagram showing an example of an AC primary component 88B included in the rectangular wave energization 88A at an electrical angle of 180 degrees.

  The AC primary component 88B shown in FIG. 3B has a voltage maximum value larger than that of the AC primary component 86B shown in FIG. That is, when the electrical angle of energization (hereinafter referred to as “energization width”) is greater than 120 degrees, the same effect as when the applied voltage to the motor coil is increased, and the rotational speed and torque of the motor are reduced. Improve.

  Enlarging the energization width is effective when it is desired to further increase the rotation speed of the motor when the PWM duty ratio is 100%. When the duty ratio is 100% or more, the applied voltage to the motor cannot be increased further by PWM, but the applied voltage can be increased by expanding the energization width as shown in FIG. It becomes possible.

  FIG. 4 is an explanatory diagram showing the rotational speed of the output shafts 36 and 38 with respect to the torque of the output shafts 36 and 38 in the wiper motors 18 and 20. 4 indicates the rotation speed of the output shafts 36 and 38 with respect to the torque of the output shafts 36 and 38 of the wiper motors 18 and 20 when the wiper blades 30 and 32 are wiped at a high speed. The straight line 116 of FIG. The rotational speed of the output shafts 36 and 38 with respect to the torque of the output shafts 36 and 38 of the wiper motors 18 and 20 when the wiper blades 30 and 32 are wiped at a low speed is shown.

  A straight line 110 in FIG. 4 indicates the rotation speed of the output shafts 36 and 38 with respect to the torque of the output shafts 36 and 38 of the wiper motors 18 and 20 when the energization width is 120 degrees. When the energization width is 120 degrees, the output shafts 36 and 38 of the wiper motors 18 and 20 cannot be rotated at the torque and rotational speed shown in the ranges 118 and 120 of FIG.

  However, when the energization width is increased to nearly 180 degrees, the output shafts 36 and 38 of the wiper motors 18 and 20 can be rotated at the torque and rotational speed indicated by the straight line 112. The wiper motors 18 and 20 can be operated at the rotational speed. The energization width is set to be close to 180 degrees but less than 180 degrees. This is because if the energization width exceeds 180, for example, a through current flows through the FET 74U and FET 76U (or FET 74V and FET 76V, FET 74W and FET 76W) connected in parallel, and the FETs 74U and 76U may be damaged.

  Furthermore, the rotational speed of the output shafts 36 and 38 of the wiper motors 18 and 20 can be improved by advancing the energization timing. FIG. 5 is an explanatory diagram showing the rotational speed of the output shafts 36 and 38 with respect to the torque of the output shafts 36 and 38 in the wiper motors 18 and 20. A straight line 114A in FIG. 5 indicates the rotational speed of the output shafts 36 and 38 with respect to the torque of the output shafts 36 and 38 of the wiper motors 18 and 20 when the wiper blades 30 and 32 are wiped at a high speed. Is shown. By enlarging the energization width to nearly 180 degrees and advancing the energization timing, the output shafts 36 and 38 are rotated at a higher speed than the rotation speed when the energization width indicated by the straight line 112 is expanded to nearly 180 degrees. Accordingly, the wiper motors 18 and 20 can be operated at the torque and the rotational speed shown in the range 122 of FIG.

  FIG. 6 is an explanatory diagram showing an example of a process of changing the duty ratio of the voltage applied to the coils 40U, 40V, and 40W. 6A shows a case where the duty ratio is low, FIG. 6B shows a case where the duty ratio is medium, and FIG. 6C shows a case where the duty ratio is 100%, that is, the voltage without PWM. The cases of generating are respectively shown. In the case of FIGS. 6A to 6C, the energization width (“energization section” in the claims) is not enlarged and the energization timing is not advanced only by changing the duty ratio. In FIG. 6, energization starts at an electrical angle of 30 degrees, and energization ends at an electrical angle of 150 degrees, so the energization width is 120 degrees. The case shown in FIG. 6 corresponds to the “first rotation control” described in the claims. In the present embodiment, the “reference speed” described in the claims is, for example, the target rotational speed of the output shafts 36 and 38 of the wiper motors 18 and 20 when the wiper switch 66 is in the low-speed operation mode selection position. It is.

  FIG. 7 is an explanatory diagram showing an example of a process of changing the energization width after the duty ratio is set to 100%. In the present embodiment, when the target rotational speed exceeds the “reference speed”, the energization width is expanded beyond 120 degrees as shown in FIG. Specifically, as shown in FIG. 7B, for example, the energization width is reduced by starting energization from the advance side from an electrical angle of 30 degrees and ending energization from the retard side from an electrical angle of 150 degrees. Set between 120 degrees and less than 180 degrees. As shown in FIG. 7B, the rotational speed and torque of the output shafts 36 and 38 of the wiper motors 18 and 20 are improved by making the energization width larger than 120 degrees. Further, in FIG. 7C, the energization width is expanded to nearly 180 degrees. 7B and 7C start energizing the coils 40U, 40V, and 40W with no PWM generated at a timing advanced by an electrical angle from the timing of the “first rotation control”, and This corresponds to the “second rotation control” described in the claims, in which the energization to the coils 40U, 40V, and 40W is terminated at a timing delayed by an electrical angle from the timing of the end of energization of “one rotation control”.

  FIG. 8 is an explanatory diagram showing an example of a process of changing the energization timing after enlarging the energization width to nearly 180 degrees. In the present embodiment, when the target rotation speed is higher than “second rotation control”, the energization timing of 0 degree advance in “second rotation control” shown in FIG. 8A is advanced. Thus, the rotational speeds of the output shafts 36 and 38 of the wiper motors 18 and 20 are further improved. In the case shown in FIG. 8B, the energization timing is advanced in the range of 0 degrees to less than 60 degrees. In the case of FIG. 8B, energization of the voltage generated without PWM to the coils 40U, 40V, and 40W is started at the timing advanced by the electrical angle from the timing of “second rotation control”, and FIG. Energization of the coils 40U, 40V, and 40W is terminated at substantially the same timing as the energization termination timing of the “first rotation control” shown in FIG. The case of FIG. 8B corresponds to “third rotation control” described in the claims.

  In FIG. 8C, the energization timing is further advanced. In the case of FIG. 8C, when the target rotational speed is higher than the “third rotation control”, the coils 40U, 40V, and 40W are PWMed at the timing advanced by the electrical angle from the timing of the “third rotation control”. The energization of the coils 40U, 40V, and 40W is completed at the timing advanced by the electrical angle from the timing of the energization end of the “first rotation control” shown in FIG. 6C. This corresponds to “fourth rotation control” recited in the claims. As shown in FIGS. 8B and 8C, when the energization timing is advanced, there is an effect of weakening the magnetic flux of the rotor. As a result, the torques of the output shafts 36 and 38 of the wiper motors 18 and 20 are “first”. Although the speed is lower than in the case of “two rotation control”, the rotation speed is improved as compared with the case of “second rotation control”.

  FIG. 9A is a time chart showing an example of an energization pattern to the coils 40U, 40V, and 40W when the energization timing is 120 degrees and the energization timing is not advanced. Energizations 102U, 102V, and 102W and energizations 104U, 104V, and 104W indicated by rectangles in FIG. 9A indicate timings when the coils 40U, 40V, and 40W are energized. In FIG. 9, the energizations 102U, 102V, and 102W and the energizations 104U, 104V, and 104W are shown as rectangles for convenience. However, in actual energization, the voltage modulated in a pulse shape by PWM is the coils 40U, 40V, and 40W. To be applied. Note that the unit time in FIG. 9 (for example, between the time t0 and the time t1) is a time during which the rotor 72 rotates 60 degrees in electrical angle. 9A is a timing corresponding to the magnetic pole position of the rotor 72 detected by the Hall sensor 70. In FIG.

  From time t0 to time t1, the FET 74W and the FET 76V are turned on, and the coil 40W is energized from the coil 40V. From time t1 to time t2, the FET 74U and the FET 76V are turned on, and the coil 40U is energized from the coil 40V. From time t2 to time t3, the FET 74U and the FET 76W are turned on, and the coil 40U is energized from the coil 40W. From time t3 to time t4, the FET 74V and the FET 76W are turned on, and the coil 40V is energized from the coil 40W. From time t4 to time t5, the FET 74V and the FET 76U are turned on, and the coil 40V is energized to the coil 40U. From time t5 to time t6, the FET 74W and the FET 76U are turned on, and the coil 40W is energized to the coil 40U. From time t6 to time t7, the FET 74W and the FET 76V are turned on, and the coil 40W is energized to the coil 40V. From time t7 to time t8, the FET 74U and the FET 76V are turned on, and the coil 40U is energized from the coil 40V.

  FIG. 9B shows an example of an energization pattern to the coils 40U, 40V, and 40W in the case of the “third rotation control” according to the claims, in which the energization timing is advanced with an energization width near 180 degrees. It is the time chart shown. 9B, the energization timings of the energizations 102U, 102V, 102W, 104U, 104V, and 104W in FIG. 9A are advanced and the energization widths are increased, and the energizations 106U, 106V, 106W, and 108U are expanded. , 108V, 108W. In the case of FIG. 9 (B), unlike the case of FIG. 9 (A), the voltage of the battery 80 is not modulated in a pulse form by PWM, but the voltage shown by the rectangular wave is applied to the coils 40U, 40V, Energize 40W.

  In general, in a brushless DC motor, when the output shaft is rotated at a high speed, it is effective to advance the electrical angle of the energization timing to each phase of U, V, and W. In the present embodiment, when the output shafts 36 and 38 of the wiper motors 18 and 20 are rotated at a high speed, the energization width is expanded and the energization timing is advanced as shown in FIG. When it is not necessary to rotate the output shafts 36 and 38 at a high speed, the energization width is 120 degrees as shown in FIG. 9A, and the timing corresponds to the magnetic pole position of the rotor 72 detected by the Hall sensor 70. Energize each phase of U, V, and W.

FIG. 10A is an explanatory view showing an example of a change in energization width when the wiper blades 30 and 32 are wiped at a high speed from the lower inversion position P2 to the upper inversion position P1, and FIG. FIG. 6 is an explanatory diagram showing an example of a change in duty ratio of a voltage applied to the wiper motors 18 and 20 when the wiper blades 30 and 32 are wiped at a high speed from the lower inversion position P2 to the upper inversion position P1. The horizontal axes in FIGS. 10A and 10B are time, but correspond to the positions of the wiper blades 30 and 32 indicated by the rotation angles of the output shafts 36 and 38 as indicated by θ _{1 to} θ ₄ . Shows time.

As shown in FIG. 10A, in the section (1) where the rotation angles of the output shafts 36 and 38 are θ ₀ to θ ₁ , the energization width is 120 degrees, but the energization width is from θ ₁ to θ _2. is enlarged in the section (2), the conducting width in theta ₂ is near 180 degrees is the maximum value. The energization width decreases in the section (3) from θ ₂ to θ ₃ , and the energization width returns to 120 degrees in the section (4) from θ ₃ to θ ₄ .

As shown in FIG. 10B, the duty ratio increases from θ ₀ and reaches the maximum of 100% at θ ₁ . Thereafter, the duty ratio is 100% from θ ₁ to θ _{3, the} duty ratio starts to decrease from θ ₃ , and becomes “0” at θ ₄ .

In this embodiment, even when the duty ratio becomes 100% in the sections (2) and (3) in FIG. 10, the energization width is controlled so that “maximum speed” is obtained at θ ₂ . As shown in FIG. 10A, the output shafts 36 and 38 are rotated at a higher speed by enlarging the energization width to nearly 180 degrees with θ ₂ . Although not shown in FIG. 10, in the present embodiment, the output shafts 36 and 38 are rotated at high speed by enlarging the energization width and advancing the energization timing.

  FIG. 11 is a flowchart showing an example of energization width and advance angle control in the wiper apparatus 10 according to the present embodiment. In step 900, the operation mode of the wiper device 10 is determined from a command signal based on the operation of the wiper switch 66.

  In step 902, the PWM duty ratio is calculated based on the target rotational speed indicated by the command signal. In step 904, whether the wiper operation mode is the high speed operation mode and whether the duty ratio calculated in step 902 exceeds 100%. Determine whether. When the duty ratio exceeds 100% in the present embodiment, there is a request to rotate the wiper motors 18 and 20 at a high speed. The higher the target rotation speed indicated by the command signal, the higher the duty ratio. In this embodiment, the duty ratio may exceed 100%. Actually, it is impossible to generate a voltage applied to the wiper motors 18 and 20 with a duty ratio of 100% or more. In the present embodiment, when the calculated duty ratio exceeds 100%, In this way, the energization width is expanded and the energization timing is advanced.

  If the determination in step 904 is affirmative, it is determined in step 906 whether or not the duty ratio exceeds 115%. If the determination in step 906 is affirmative, the current-carrying width is close to 180 degrees in step 908. Specifically, the dead time which is the delay time of the switching operation set so that the FET 74 and FET 76 are not turned on at the same time is considered. The energization width is less than 180 degrees.

  In step 910, it is determined whether the current value of the rotation speed of the output shafts 36, 38 calculated from the rotation angles of the output shafts 36, 38 detected by the rotation angle sensors 42, 44 is less than the target value indicated by the command signal. To do. If the determination in step 910 is affirmative, the energization timing is advanced in step 912 to energize the voltage generated without PWM, and the procedure proceeds to step 920. If a negative determination is made in step 910, the advance angle of the energization timing is decreased in step 914 to energize the voltage generated without PWM, and the procedure proceeds to step 920.

  In the case of negative determination in step 904, the voltage generated by PWM is energized at step 916 with an energization width of 120 degrees and no advance timing, and the procedure proceeds to step 920.

  In the case of negative determination in step 906, in step 918, the energization width is set between 120 degrees and nearly 180 degrees in consideration of the dead time, and the voltage generated without PWM without energization timing advance is energized. The procedure moves to step 920. The energization width increases as the duty ratio calculated according to the rotation speed indicated by the command signal increases. In step 918, “no advance angle (advance angle = 0 degree)” is energized at a timing corresponding to the position of the magnetic pole of the rotor 72 by 1/2 of the difference between the electrical angle of the enlarged energization width and 120 degrees. The energization is started at a timing advanced from the energization start timing at the energization width of 120 degrees, and the timing is delayed by 1/2 of the difference from the energization start timing at the energization width of 120 degrees. This means that energization is terminated.

  In step 920, snow puddle detection is performed to detect whether or not the wiping operation of the wiper blades 30 and 32 is hindered by an obstacle such as snow. In the present embodiment, as an example, when the rotational speed of the output shafts 36 and 38 is equal to or lower than the threshold speed, or when the motor current detected by the current detection unit 68 is equal to or higher than the threshold current, the result is affirmative in step 920. Make a decision. In the case of an affirmative determination at step 920, the energization width is set between 120 degrees and nearly 180 degrees in consideration of the dead time in step 922, and the voltage generated without PWM without energization timing advance is energized. Return processing. If the determination in step 920 is negative, the process returns. Note that “no advance angle (advance angle = 0 degree)” in step 922 is the same as “no advance angle (advance angle = 0 degree)” in step 918.

  As described above, in the present embodiment, the energization width of the applied voltage of the wiper motors 18 and 20 is expanded and the energization timing is advanced, so that the rotational speeds of the output shafts 36 and 38 of the wiper motors 18 and 20 are increased. Both torques can be improved. With this control, the output shafts 36 and 38 of the wiper motors 18 and 20 can be rotated at a higher speed than when the PWM duty ratio reaches 100%.

  According to the present embodiment, the power supply voltage has an upper limit, and the output shafts 36 and 38 of the wiper motors 18 and 20 are higher than when the duty ratio is 100%, that is, the same voltage as the upper limit of the power supply voltage is applied to the wiper motors 18 and 20. Can be rotated at high speed and with high torque, and it becomes easy to eliminate obstacles such as a snow pool on the windshield glass 12. Even if the wiper motors 18 and 20 have a small rating, the output shafts 36 and 38 can be rotated at high speed and with high torque.

  Further, in the present embodiment, when the output shafts 36 and 38 of the wiper motors 18 and 20 are rotated at high speed, the duty ratio is set to 100% so that the FETs 74U to 76W are not switched and the application to the wiper motors 18 and 20 is performed. A voltage can be generated. Switching elements such as FETs cause switching loss that loses power when switching operation occurs, and electromagnetic noise is generated. By setting the duty ratio to 100%, switching loss and generation of electromagnetic noise can be suppressed. it can.

  In this embodiment, a direct drive tandem type wiper device provided with the wiper motor 18 of the left wiper device 14 and the wiper motor 20 of the right wiper device 16 is taken as an example. It is also possible to apply the rotation control described above to a wiper device of a type that transmits to the left and right wipers.

DESCRIPTION OF SYMBOLS 10 ... Wiper apparatus, 12 ... Wind shield glass, 14 ... Left wiper apparatus, 16 ... Right wiper apparatus, 18, 20 ... Wiper motor, 22 ... Deceleration mechanism, 26, 28 ... Wiper arm, 30, 32 ... Wiper blade, 36, 38 ... Output shaft, 40 ... Stator, 40U, 40V, 40W ... Coil, 42, 44 ... Rotation angle sensor, 50 ... Standby circuit, 52 ... Command value calculation unit, 54 ... Motor position estimation unit, 56 ... Hall sensor edge detection unit , 58 ... energization control unit, 60 ... wiper control circuit, 60 A ... drive circuit, 60 B ... wiper ECU, 62 ... wiper control circuit, 62 A ... drive circuit, 62 B ... wiper ECU, 64 ... vehicle control circuit, 66 ... wiper switch, 68 ... Current detection unit, 70 ... Hall sensor, 72 ... Rotor, 74U, 74V, 74w, 76U, 76V, 76W ... FE 80 ... battery, 82 ... noise prevention coil, 84A, 84B ... smoothing capacitor, 86A ... rectangular wave energization, 86B ... AC primary component, 88A ... rectangular wave energization, 88B ... AC primary component, 92, 94, 96 ... Straight line, 102U, 102V, 102W, 104U, 104V, 104W, 106U, 106V, 106W, 108U, 108V, 108W ... energization, 110, 112, 114, 114A, 116 ... straight line, 118 ... range, 122 ... range, P1 ... Upper inversion position, P2 ... Lower inversion position, P3 ... Storage position, R1 ... Resistance, RT ... Chip thermistor, Vcc ... Control voltage, t0, t1, t2, t3, t4, t5, t6, t7, t8 ... Time

Claims (4)

A drive unit that rotationally drives a wiper motor that includes a rotor and a coil that generates a rotating magnetic field, and that wipes the wiper blade by rotating the rotor according to the rotating magnetic field;
When the command value is the first reference rotation speed, a voltage generated by pulse width modulation is applied to the coil at a timing corresponding to the rotation position of the rotor, and the rotation speed of the wiper motor is set to the first reference rotation speed. Controlling the drive unit so that the first rotation control to control the speed is performed,
When the command value is a second reference rotational speed that is faster than the first reference rotational speed, a voltage generated so as to be continuously energized from the start of energization to the end of energization is an electrical angle from the energization start timing of the first rotation control. Energization is started at the timing advanced by, and energization is terminated at a timing delayed by an electrical angle from the energization end timing of the first rotation control, and the rotation speed of the wiper motor is controlled to the second reference rotation speed. A control unit that controls the drive unit so that the second rotation control is performed;
Including wiper device.   When the command value is a third reference rotational speed that is faster than the second reference rotational speed, the control unit generates a voltage generated so as to be continuously energized from the start of energization to the end of energization. Energization is started at a timing advanced by an electrical angle from the start timing, the energization is terminated at substantially the same timing as the energization end timing of the first rotation control, and the energization section from the energization start to the energization end is set in the second rotation control. 2. The wiper device according to claim 1, wherein the drive unit is controlled so that a third rotation control is performed in which the rotation speed of the wiper motor is controlled to the third reference rotation speed by expanding beyond the energization section.   When the command value is a fourth reference rotational speed that is faster than the third reference rotational speed, the control unit generates a voltage generated so as to be continuously energized from the start of energization to the end of energization. Energization is started at a timing advanced by an electrical angle from the start timing, and energization is terminated at a timing advanced by an electrical angle from the energization end timing of the first rotation control. 3. The wiper according to claim 2, wherein the drive unit is controlled to perform a fourth rotation control that controls the rotation speed of the wiper motor to the fourth reference rotation speed by enlarging the energization section of the second rotation control. apparatus.   The control unit performs the first rotation control when the duty ratio of the pulse width modulation calculated according to the command value is less than 100%, and the duty ratio calculated according to the command value is 100% The said 2nd rotation control is started when it becomes, and after that, any one of the said 2nd rotation control, the said 3rd rotation control, and the said 4th rotation control is performed according to the said command value. Wiper device.