JP6372958B2 - Wiper system - Google Patents

Description

  The present invention relates to a control technique for a vehicle wiper device mounted on an automobile or the like, and more particularly to a control technique effective when applied to a restart operation when a wiper blade stops at a place other than a normal stop position.

  A vehicle such as an automobile is provided with a wiper device that wipes off rain adhered to a windshield (windshield) and splashes from a front vehicle in order to secure a driver's field of view in rainy weather. The wiper device has a wiper arm that is swing-controlled by a wiper driving device, and a wiper blade that contacts the windshield is attached to the tip of the wiper arm. The wiper arm swings by changing the rotational movement of the motor to a reciprocating movement by the link mechanism, and the wiper blade performs a wiping operation on the windshield by the reciprocating movement of the wiper arm.

  2. Description of the Related Art Conventionally, in a wiper device such as an automobile, a system is known in which a current position of a wiper arm on a glass surface is detected, and a wiper blade is reciprocated between upside down positions based on the detected data (for example, Patent Document 1). In such a wiper apparatus, when controlling the operation of the wiper arm, the target speed of the arm is set corresponding to the angular position of the wiper arm. The wiper control device detects the current position of the wiper arm, and feedback-controls the wiper motor based on the detected current arm position and the target speed, and the wiper blade performs a reciprocating wiping operation between the upside down positions under the feedback control. I do.

JP 2007-126149 A JP 2009-113555 A

  On the other hand, in the wiper device, if the ignition switch is turned off during operation, the wiper arm may stop at a place other than the normal stop position. In such a case, in the wiper device that operates the driver side (DR side) and the passenger seat side (AS side) synchronously using separate motors, the wiper device is restarted without recognizing the blade position, and normal operation is performed. When starting, there is a possibility that the blades may interfere with each other. In particular, when the DR side and AS side blades are switched, the blades may interfere with each other immediately after restarting, and the system may be stopped. Further, even in a 1-motor driven tandem wiper device, if the blade position at the time of restart cannot be grasped, the motion after restart may be unstable.

  Therefore, in the wiper device, it is necessary to know the current position of the wiper blade and recognize the presence / absence of blade replacement in order to prevent the occurrence of interference after restart. For this reason, in the conventional wiper device, an absolute angle sensor such as an MR sensor is used in order to detect the operating angle of the motor. However, such a sensing method requires the use of a very expensive element. There was a problem that the cost increased.

  An object of the present invention is to provide a wiper apparatus control technique that can accurately detect the position of a wiper blade with a simple configuration, thereby reducing system cost.

The wiper system of the present invention includes two wiper blades that perform a reciprocating wiping operation on a wiping surface, an electric motor for reciprocating the wiper blade, and a control unit that controls the operation of the electric motor. The electric motor includes a rotating shaft, a reduction gear that meshes with a gear portion formed on the rotating shaft, and a first sensor that outputs a signal along with the rotation of the rotating shaft. And a second sensor unit that outputs a signal along with the rotation of the reduction gear. The first sensor unit includes a first sensor magnet attached to the rotating shaft, and a first sensor magnet. A first magnetic sensor that outputs a predetermined signal along with the rotation, and the second sensor unit includes a second sensor magnet attached to the reduction gear, and a position associated with the rotation of the second sensor magnet. The first sensor magnet is formed in a ring shape, a plurality of magnetic poles are arranged along the circumferential direction, and rotates together with the rotating shaft. The magnetic sensor is disposed to face the first sensor magnet, outputs a pulse signal in accordance with a change in polarity of the magnetic pole of the opposed first sensor magnet, and the second sensor magnet is formed in a disc shape. rotates with the reduction gear, the circumferential directionally arranged poles at unequal pitches along Rutotomoni has two pole group provided in line symmetry, the magnetic pole group are pole width is narrowed gradually A plurality of magnetic poles are alternately arranged at unequal pitches, and the second magnetic sensor faces the second sensor magnet and is separated by 180 ° along the circumferential direction of the second sensor magnet. Symmetric to position The control means outputs a different signal depending on the polarity of the magnetic poles of the second sensor magnets opposed to each other, and the control means switches the magnetic poles of the second sensor magnets detected by the two second magnetic sensors. An area where the wiper blade is present on the wiping surface is detected based on a time difference .

  In the present invention, magnetic poles are arranged at unequal pitches along the circumferential direction in the second sensor magnet of the second sensor unit, and the two second magnetic sensors arranged opposite to the second sensor magnet are used. The area on the wiping surface where the wiper blade exists is detected based on the combination of the output signals. Thereby, the position of the wiper blade can be grasped by an inexpensive configuration without using expensive sensors. Therefore, although the configuration is simple, the return from the abnormal stop to the normal control can be surely performed, and the system cost can be reduced.

In the wiper system, together with the two wiper blades are arranged to face the wiping surface, it divides the wiping region of the wiper blade into four areas, the control means, wherein the wiper blade is the four areas It may be possible to detect which area is present.

  In this case, for the two wiper blades, the control means detects the front-rear relationship of the wiper blades based on the areas where the wiper blades are detected, and determines whether the wiper blades are replaced. You may judge. In addition, when it is detected that the two wiper blades are present in the same area, the control unit operates the wiper blade in the upward reverse position direction, and when the electric motor is locked, It may be determined that the wiper blades are in contact with each other by replacing the wiper blades, and the normal wiper blades may be moved toward the upper reversal position in the normal control.

  Further, when the wiper blade replacement is detected based on the area where the wiper blade is present, the control means causes the wiper blade on the following side to precede the upper wiper position during normal control. You may make it operate | move toward a direction. In addition, the control means may include the wiper blade in the area where the wiper blades do not interfere with each other even when the replacement of the wiper blade is detected based on the area where the wiper blade is present. If present, the wiper blades may be operated toward the upper reversal position in the same order as in normal control.

  In this case, the control means may detect a difference in switching time of the magnetic poles using a pulse signal output from the first magnetic sensor while the magnetic poles of the second sensor magnet are switched. Further, the control means calculates a rotation angle of the second sensor magnet by multiplying a difference in magnetic pole switching time of the second sensor magnet by a predetermined angle calculation coefficient, and detects the position of the wiper blade. Anyway.

  In the wiper system of the present invention, a first sensor unit that outputs a signal as the motor rotation shaft rotates and a second sensor unit that outputs a signal as the reduction gear rotates are provided. Magnetic poles are arranged at unequal pitches along the circumferential direction in the second sensor magnet of the magnet, and wiper blades exist based on output signals from the two second magnetic sensors arranged opposite to the second sensor magnet Since the area on the wiping surface to be detected is detected, the position of the wiper blade can be grasped by an inexpensive configuration without using expensive sensors, and the system cost can be reduced.

It is explanatory drawing which shows the whole structure of the wiper system which is one Embodiment of this invention. It is explanatory drawing which shows the structure of an electric motor. It is a table | surface which shows the relationship between the output (polarity determination) from a magnetic sensor, and the area where a wiper blade exists. It is a table | surface which shows the combination of the area where each wiper blade exists. It is a block diagram which shows the structure of the control system of a wiper control apparatus. 3 is a flowchart illustrating a control procedure in the wiper system according to the first embodiment. (A) is explanatory drawing which shows the structure of the sensor magnet used for the wiper system which is Embodiment 2 of this invention, (b) is a description which shows the state which the worm wheel rotated 90 degrees from the state of (a). FIG. 6 is a flowchart illustrating a control procedure in the wiper system according to the second embodiment.

(Embodiment 1)
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is an explanatory diagram showing the overall configuration of a wiper system according to an embodiment of the present invention. The wiper system of FIG. 1 has a counter-wiping type device configuration, and is arranged so that the wiper arm 1a on the driver's seat side (DR side) and the wiper arm 1b on the passenger seat side (AS side) face each other. Wiper blades 2a and 2b (hereinafter abbreviated as blades 2a and 2b) are attached to the wiper arms 1a and 1b, respectively. The blades 2a, 2b are in elastic contact with the windshield 3 by spring members (not shown) or the like built in the wiper arms 1a, 1b.

  The vehicle body is provided with two wiper shafts (pivot shafts) 4a and 4b. The wiper arms 1a and 1b are respectively attached to the wiper shafts 4a and 4b at the base ends. Note that “a, b” in the reference numerals indicates members and portions related to the driver's seat side and the passenger seat side, respectively. In order to swing the wiper arms 1a and 1b, the system is provided with two electric motors 6a and 6b (hereinafter abbreviated as motors 6a and 6b) that are PWM duty controlled. The motors 6 a and 6 b are constituted by a motor body 7 and a speed reduction mechanism 8.

  The motors 6a and 6b are driven and controlled by wiper control devices (control means) 10a and 10b and rotate forward and backward. A wiper control device 10a that drives and controls the motor 6a is connected to an ECU 11 that is a vehicle-side controller via an in-vehicle LAN 12. Switch information such as ON / OFF of a wiper switch, Lo, Hi, INT (intermittent operation), engine start information, and the like are input to the wiper control device 10a from the ECU 11 via the LAN 12. The wiper control devices 10a and 10b are connected by a communication line 13.

  In the wiper system of FIG. 1, the motors 6a and 6b are feedback-controlled (PI control) based on the position information of the blades 2a and 2b. Here, the target speeds of both blades are set corresponding to the positions of the blades 2a and 2b, and stored in advance in the wiper control devices 10a and 10b in the form of a map or the like. The wiper control devices 10a and 10b detect the current positions of the blades 2a and 2b, and also detect the moving speeds of the blades 2a and 2b from the rotational speeds of the wiper shafts 4a and 4b. Then, the current speeds of the blades 2a and 2b are compared with the target speeds of the blades 2a and 2b at the positions, and the motors 6a and 6b are appropriately controlled according to the difference between the target speed and the current speed.

  In order to perform such feedback control, the motors 6a and 6b are provided with a first sensor unit 14 having a first sensor magnet 31 and a second sensor unit 15 having a second sensor magnet 32 (hereinafter referred to as “the first sensor magnet 31”). The first sensor magnet 31 is abbreviated as a magnet 31, and the second sensor magnet 32 is abbreviated as a sensor magnet 32). FIG. 2 is an explanatory diagram showing the configuration of the motor 6a. The motor 6b has the same configuration. As shown in FIG. 2, a rotor 33 is rotatably disposed on the motor body 7 of the motor 6a. A worm 35 is formed on the rotating shaft 34 of the rotor 33. The worm 35 meshes with a worm wheel (deceleration gear) 36 disposed in the speed reduction mechanism 8. The worm wheel 36 is attached to a wiper shaft 4a connected to the wiper arm 1a.

  The sensor magnet 31 of the first sensor unit 14 is formed in a ring shape and is attached to the rotating shaft 34. A plurality of magnetic poles (N and S poles) are equally formed on the sensor magnet 31 along the circumferential direction. In the first sensor unit 14, two first magnetic sensors 37 and 38 (hereinafter, abbreviated as magnetic sensors 37 and 38) are arranged in the vicinity of the outer periphery of the sensor magnet 31 so as to be separated in the radial direction. The magnetic sensors 37 and 38 are provided at positions 90 degrees apart along the circumferential direction of the sensor magnet 31. Hall sensors for detecting alternating magnetic fields are used for the magnetic sensors 37 and 38, and pulse signals that are 90 ° out of phase are transmitted from both sensors (A phase and B phase). The amount of operation (operation angle) of the wiper arms 1a and 1b is calculated from the number of pulses output from the magnetic sensors 37 and 38. Further, from the signal output order, the rotation direction of the rotary shaft 34 is detected, and the operation direction (forward path or return path) of the wiper arms 1a, 1b (blades 2a, 2b) is grasped.

  The sensor magnet 32 of the second sensor unit 15 is also formed in a ring shape and is attached to the worm wheel 36. In the sensor magnet 32, two magnetic poles 32N and 32S are formed along the circumferential direction. The sensor magnets 32 are magnetized at unequal pitches, and the magnetic pole 32N is formed at 300 ° and the magnetic pole 32S is formed at 60 °. In the second sensor unit 15, two second magnetic sensors 39 and 40 (hereinafter, abbreviated as magnetic sensors 39 and 40) are arranged in the vicinity of the end face of the sensor magnet 32 so as to be separated in the axial direction. The magnetic sensors 39 and 40 are provided at positions separated by 30 ° along the circumferential direction of the sensor magnet 32. For the magnetic sensors 39 and 40, a Hall IC for detecting a unidirectional magnetic field is used. For example, a predetermined detection signal is output when the south pole is close. When the worm wheel 36 rotates, the sensor magnet 32 also rotates with it, and the magnetic pole of the sensor magnet 32 facing the magnetic sensors 39 and 40 changes. A signal corresponding to the polarity (N pole or S pole) is output from the magnetic sensors 39 and 40 (C phase / D phase).

  In the wiper system, the rotational position of the sensor magnet 32 of both the motors 6a and 6b, that is, the position (area) where the blades 2a and 2b exist, by combining the C-phase and D-phase signals output from the magnetic sensors 39 and 40 ) Is detected. FIG. 3 is a table showing a relationship between outputs (polarity determination) from the magnetic sensors 39 and 40 and areas where the blades 2a and 2b exist. As shown in FIG. 3, there are four combinations (N, S), (S, S), (S, N), and (N, N) for combinations of polarity determination by the magnetic sensors 39 and 40. As described above, the worm wheel 36 is attached to the wiper shaft 4a, and the sensor magnet 32 rotates together with the wiper shaft 4a. That is, the rotation angle of the sensor magnet 32 corresponds to the operation angle of the wiper arms 1a and 1b (blades 2a and 2b).

Therefore, four areas are provided corresponding to the operating angles of the blades 2a and 2b, and the magnetic poles of the sensor magnet 32 are set so that the combination of the polarities detected by the magnetic sensors 39 and 40 changes for each area. FIG. 3 shows the correspondence. As shown in FIG. 1, here, the following four areas are set as areas where the blades 2a and 2b exist.
(1) Storage position S to lower inversion position L
(2) Lower inversion position L to center position C
(3) Center position C to upper reverse position PU
(4) Upper reverse position PU to upper reverse position U
In this case, in the areas (1) and (2), the wiping ranges of the blades 2a and 2b overlap, and there is a possibility that the two interfere with each other. On the other hand, in the areas (3) and (4), the wiping ranges of the blades 2a and 2b do not overlap and they do not interfere with each other. A reset position R is provided at the boundary between the areas (3) and (4) in order to detect the absolute positions of the blades 2a and 2b.

  In each of the areas (1) to (4), combinations of polarities detected by the sensor magnet 32 are different. As shown in FIG. 3, (N, S) in area (1), (S, S) in (2), (S, N) in (3), (N, N) in (4) Is detected by the magnetic sensors 39 and 40. Therefore, by looking at the output signals of the magnetic sensors 39 and 40, it is possible to grasp in which area the blades 2a and 2b are currently located. Thereby, in the system, even when the system is restarted, the positions of the blades 2a and 2b can be grasped, and the blades 2a and 2b stop at the normal stop positions (storage position, lower reverse position, upper reverse position). It can be estimated whether or not.

  On the other hand, when the wiper system is operating normally, the blades 2a and 2b are both in the same area, or the AS side is below the DR side (storage position side). Therefore, it is detected in which area each of the blades 2a and 2b exists, and it is detected whether or not the blade is not replaced. FIG. 4 is a table showing combinations of areas in which the blades 2a and 2b exist. In the case of the hatched relationship in FIG. 4, the blades 2a and 2b on the DR side and AS side are switched. Become.

  The control information of the motors 6a and 6b is exchanged between the wiper control devices 10a and 10b via the communication line 13, and the motors 6a and 6b are synchronously controlled based on the positional relationship between both blades. That is, the wiper control devices 10a and 10b first perform forward / reverse control of the motors 6a and 6b based on the blade position on its own side. At the same time, the wiper control devices 10a and 10b control the motors 6a and 6b based on the blade position information of both blades 2a and 2b, and control the wiper system so that the blades do not interfere with each other and the angle difference does not increase. . As a result, the blades 2 a and 2 b swing between the lower inversion position L and the upper inversion position U in the wiping range 5, and rain and snow attached to the windshield 3 are wiped off.

  FIG. 5 is a block diagram showing the configuration of the control system of the wiper control device 10 according to the present invention. Since the wiper control devices 10a and 10b have the same configuration, only the wiper control device 10a will be described in FIG. 5 and the following description. As shown in FIG. 5, the wiper control device 10 a is provided with a CPU 21 and a data transmission / reception unit 22. The wiper control device 10a is connected to the ECU 11 via the LAN 12. Various types of vehicle information such as a wiper switch setting state (ON / OFF, operation mode setting such as Lo, Hi, and INT) and an engine start signal are input from the ECU 11 to the wiper control device 10a. The wiper control device 10a further includes a ROM 23 that stores a control program and various control information, and a RAM 24 that stores control data such as a motor rotation speed and a blade current position.

  The CPU 21 is a central processing unit. Here, the CPU 21 connected to the ECU 11 is the master side, and the CPU of the wiper control device 10b (not shown) is the slave side. The CPU 21 of the wiper control device 10 a is connected to the CPU of the wiper control device 10 b via the data transmission / reception unit 22 and the communication line 13. Both CPUs exchange position information and operation instructions with each other through the communication line 13. The CPU 21 on the master side controls the operation of the motor 6a based on the position information of the blade 2b sent from the wiper control device 10b and the position information of itself (blade 2a) according to the state of the wiper switch. The CPU on the slave side controls the operation of the motor 6b based on the position information of the blade 2a and the position information of itself (blade 2b) sent from the wiper control device 10a in accordance with an instruction from the wiper control device 10a.

  The CPU 21 is provided with a blade position detection unit 25 that detects the current position of the blade 2 a based on sensor signals from the magnetic sensors 37 and 38 and the magnetic sensors 39 and 40. Further, the CPU 21 examines the positional relationship between the blade 2b and the blade stop position determination unit 26 that determines whether or not the blade 2a is stopped at the normal stop position based on the result of the blade position detection unit 25. In addition, a blade order determination unit 27 for determining replacement of the blades 2a and 2b is provided. Further, the CPU 21 instructs the motor 6a to determine the direction of rotation, Duty, and the like based on the drive current of the motor 6a, and the motor 6a to rotate the blade 2a between the upside down positions. A drive control instruction unit 29 is provided to operate appropriately.

  In the wiper system according to the present invention having such a configuration, after the wiper switch is turned on, the stop position of the blades 2a and 2b and the replacement of the blades are determined at the time of the first upward operation. The system is controlled so that no blade interference occurs. FIG. 6 is a flowchart showing a control procedure in the first upward operation. As shown in FIG. 6, first, the lock determination of the motors 6a and 6b is first performed by the motor lock determination unit 28 (step S1). If the blades 2a and 2b exist in the areas (1) and (2), and the blades are replaced there, the DR blade 2a that has acted first hits the AS blade 2b and the motor 6a is locked. It becomes. The motor lock state is determined by the drive current value of the motor. If the current value exceeds a predetermined value, it is determined that the motor lock has occurred.

  When the motor lock is detected in step S1, it means that the blades 2a and 2b exist in the areas (1) and (2), and the blades are replaced. Therefore, in this case, the process proceeds to step S2, and the drive control instruction unit 29 causes the AS blade 2b to advance and retract to the upper reverse position, and then moves the DR blade 2a to the upper reverse position to exit the routine. . After the blades 2a and 2b are retracted to the upper reversal position, normal control is performed to return to normal operation.

  If the motor lock is not detected in step S1, the process proceeds to step S3, and it is determined whether or not the blade is replaced. The determination in S3 is performed by the blade order determination unit 27 by checking whether a relationship such as the hatched portion in FIG. 4 has occurred on the DR side and the AS side. For example, when the DR side is the area (1) and the AS side is detected as the area (3), the AS side exists ahead of the DR side that should have preceded, and it is determined as “replacement”. In this case, the replacement in the areas ((1), (2)) where the motor lock is caused by the blade interference has already been determined in S1, and here, the replacement in the areas (3), (4) or DR When the difference between the side and the AS side is large (for example, DR side: (1); AS side: (3)) is determined. In the case of areas (3) and (4), the replacement of blades in the same area will not cause any interference because there is no interference with the blades. In the case of (1) and (2) This is determined by lock detection.

  If it is determined in step S3 that the blade has been replaced, the process proceeds to step S4, and in the same manner as in S2, the AS side blade 2b is advanced and retracted to the upper reverse position, and then the DR side blade. 2a is moved to the upper reverse position. After the blades 2a and 2b are retracted to the upper reversal position, normal control is performed to return to normal operation. On the other hand, if it is determined in step S3 that the blade is not replaced, the process proceeds to step S5, and the blade stop position determination unit 26 determines whether the stop position is appropriate.

  When the blades 2a and 2b are stopped in the area (3), this means that the blade is stopped at a place other than the normal stop position (storage position, lower reverse position, upper reverse position). Therefore, in step S5, it is confirmed whether or not the blades 2a and 2b exist in the area (3), that is, whether or not the blades 2a and 2b are in the area (3) from the beginning in the first upward operation. . If the blades 2a and 2b are in the area (3) in S5, it is determined that the blade 2a and 2b are stopped at the abnormal stop position, and the process proceeds to step S6. In this case, since the process proceeds from S1 to S3 to S5 and the process proceeds to step S6, no blade replacement has occurred. Accordingly, here, as in the normal operation, the DR side blade 2a is operated in advance to be retracted to the upper reverse position, and then the AS side blade 2b is moved to the upper reverse position. After the blades 2a and 2b are retracted to the upper reversal position, normal control is performed to return to normal operation.

  As described above, in the wiper system according to the present invention, the sensor magnets 32 for area detection magnetized at unequal pitches are arranged on the wiper shafts 4a and 4b, and the polarity is detected by the two magnetic sensors 39 and 40. To do. Corresponding to the combination of the four magnetic poles detected at that time, the blade wiping area is divided into four areas, so that the stop position (area) of the blades 2a and 2b can be detected, and the blade stops at the normal stop position. It can be estimated whether or not. At this time, if the blades 2a and 2b are not stopped at the normal stop positions, the blades are temporarily retracted in the upward reversal direction in the order of the DR side and the AS side, and then the return operation is returned to the normal control. As a result, even when the vehicle stops at an abnormal position, it is possible to return to the normal operation with a smooth operation with no sense of incongruity.

  If it is determined by area recognition that the order of the blades is changed, the blades are retracted in the upward direction in the order of the AS side and the DR side. Then, the normal operation is returned from the return path operation. Thereby, it is possible to return to the normal operation while avoiding interference between the blades. If a change occurs within the range of the normal stop position, after the lock state is detected by the motor lock detection, the blades are retracted in the upward reverse direction in the order of AS side and DR side, and interference between the blades occurs. While returning to normal operation.

(Embodiment 2)
Next, as a second embodiment of the present invention, a configuration in which a plurality of unequal pitch magnetic poles are arranged symmetrically will be described as a sensor magnet for area detection. Fig.7 (a) is explanatory drawing which shows the structure of the sensor magnet 41 used for the wiper system which is Embodiment 2 of this invention. The configuration other than that related to the sensor magnet 41 is the same as that of the wiper system of the first embodiment, and the same members and portions as those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

  As shown in FIG. 7A, the sensor magnet 41 is also formed in a ring shape and attached to the worm wheel 36. There are magnetic pole groups 42 and 43 that are equally divided into left and right by 180 °. In the magnetic pole groups 42 and 43, a plurality of magnetic poles (N pole and S pole) are alternately arranged at unequal pitches, and are symmetrical with respect to the center line CL (line symmetry). The magnetic pole group 42 is provided for 180 ° so that the magnetic pole width gradually narrows starting from the N pole. On the other hand, the magnetic pole group 43 is provided by 180 ° on the opposite side to the magnetic pole group 42 so that the magnetic pole width gradually narrows starting from the S pole. Eight magnetic poles are formed in each of the magnetic pole groups 42 and 43.

  Near the end face of the sensor magnet 41, two second magnetic sensors 44 and 45 (hereinafter abbreviated as magnetic sensors 44 and 45) are arranged apart from each other in the axial direction. The magnetic sensors 44 and 45 are provided at positions 180 degrees apart along the circumferential direction of the sensor magnet 41, and are arranged symmetrically with respect to the center O of the sensor magnet 41 along the center line CL. The magnetic sensors 44 and 45 use alternating magnetic field detection Hall ICs, and a detection signal is output when the polarity of the opposing magnetic poles is switched. When the worm wheel 36 rotates, the sensor magnet 41 also rotates with it, and the magnetic pole of the sensor magnet 32 facing the magnetic sensors 44 and 45 changes. A detection signal is output from the magnetic sensors 44 and 45 each time the polarity changes (C phase / D phase).

  In this case, in the case of the combination of symmetrically unequal pitch sensor magnets 41 and symmetrically arranged magnetic sensors 44 and 45 as shown in FIG. 7A, the polarity of the sensor magnet 41 changes between the magnetic sensor 44 side and the magnetic sensor 45 side. There is a difference in timing. For example, when the worm wheel 36 rotates with the sensor magnet 41 in the state of FIG. 7A (when the wiper arm is activated), the magnetic sensor 45 side (D phase side) is more than the magnetic sensor 44 side (C phase side). Polarity changes quickly. That is, the D-phase side is switched at a timing when the C-phase side is not switched. On the other hand, when the worm wheel 36 rotates 90 ° from the state shown in FIG. 7A and becomes in the state shown in FIG. 7B, the C-phase side and the D-phase side are switched at substantially the same timing.

  Thus, there is a correlation between the rotation angle of the worm wheel 36 (that is, the operating angle of the wiper arms 1a and 1b) and the combination of the switching times of the C-phase side and the D-phase side. The switching time varies depending on the wiper arm position. On the other hand, the A-phase and B-phase pulses from the magnetic sensors 37 and 38 are output as the motor (rotor 33) rotates. Accordingly, the number of A and B phase pulses output while the C and D phases are switched also changes depending on the wiper arm position. Therefore, in the system of the second embodiment, the current positions of the wiper arms 1a and 1b are detected using the number of A-phase (or B-phase) pulses output when switching between the C and D phases.

  In the system according to the second embodiment, as shown in FIG. 7B, when the worm wheel 36 is rotated by 90 °, the range (angle) of the C phase and the D phase is equal, and the C and D phases are switched. The number of A-phase pulses output to the same is also equal. In contrast, when the rotation angle of the worm wheel 36 is smaller than 90 °, C> D, and when it is larger than 90 °, C <D, and the number of A-phase pulses detected during the phase change has the same relationship. . That is, there is a certain correlation between the rotation angle of the worm wheel 36 and the time interval of the output signals from the magnetic sensors 44 and 45. Accordingly, the number of A-phase pulses output when the C phase is switched is α, the number of A-phase pulses output when the D phase is switched is β, and the rotation of the worm wheel 36 is determined by looking at the difference between α and β. An angle can be detected.

Here, as shown in the following equation, the operating angle of the sensor magnet 41 is calculated by multiplying the difference between α and β by a predetermined angle calculation coefficient γ (a constant determined by the pulse width (resolution) of the A phase), and calculating 90 ° By subtracting from 0 °, the current positions of blades 2a and 2b (initial angle X in the case of midway stop) are calculated.
X = 90 ° − (α−β) × γ (formula (1))
α: Number of A-phase pulses corresponding to C-phase change β: Number of A-phase pulses corresponding to D-phase change γ: Angle calculation coefficient The value calculated by equation (1) may be mapped in advance and stored in the ROM 23. The CPU 21 determines the angle X with reference to the map from the detected values of α and β.

  FIG. 8 is a flowchart showing a procedure of area recognition processing in the second embodiment. As shown in FIG. 8, first, in step S11, the switching state between the C phase and the D phase is observed. If there is no switching to either the C phase or the D phase, the routine is exited. On the other hand, if both the C phase and the D phase are switched, the process proceeds to step S12 to check whether the C phase is switched. At this time, when the C phase is switched, the process proceeds to step S13, and the number of A phase (or B phase) pulses output during the C phase switching is detected (α).

  On the other hand, when there is no switching to the C phase or after α is detected in step S13, the process proceeds to step S14 to check whether the D phase has been switched. At this time, when the D phase is switched, the process proceeds to step S15, and the number of A phase (or B phase) pulses output during the C phase switching is detected (β). In this case, since the processes after step S12 are executed in a state where both the C phase and the D phase are switched, α and β are grasped through steps S14 and S15.

  After obtaining α and β, the process proceeds to step S16, and the current position (angle X) of the blade is calculated from these values based on the equation (1). As described above, the process of step S16 is performed with reference to the angle calculation map stored in the ROM 23. The angle X of the worm wheel 36 has a correlation with the operation angle of the wiper arms 1a and 1b, whereby the movement amount of the blades 2a and 2b can be calculated and the current position can be grasped.

  As described above, the system according to the second embodiment uses a ring magnet in which magnetic poles starting from the N pole and in which the interval between the N pole and the S pole is gradually narrowed in the range of 180 ° are arranged in a line symmetry. The magnetic flux change is detected by a magnetic sensor arranged in the area. Then, based on the polarity switching timing detected by the two magnetic sensors, the blade position is detected. Accordingly, it is possible to detect the angle of the blade initial position when the wiper is restarted by using an inexpensive element or circuit configuration without using an expensive angle sensor or the like, and the system cost can be reduced.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above-described embodiment, two electric motors are arranged symmetrically with respect to the windshield 3, and the wiper device is a counter-wiping type wiper device that performs a wiping operation so that the wiper arms on the driver's seat side and the passenger seat side face each other. Although an example to which the invention is applied has been shown, the invention can also be applied to a tandem type wiper device that wipes the wiper arms on the driver's seat side and the passenger seat side in substantially the same direction.

  In the above-described embodiment, the combination of the sensor magnet and the Hall IC is shown as means for detecting the rotation angle of the motors 6a and 6b. However, the rotation angle of the rotary shaft 34 is detected by a rotary encoder or MR sensor. Also good. Further, the rotation angle of the wiper shafts 4a and 4b may be detected by using a rotation angle sensor such as a rotary encoder or MR sensor. Is inexpensive and has few failures.

  On the other hand, in the above-described embodiment, the magnetic sensors 37 and 38 are provided at positions separated by 90 ° in the circumferential direction of the sensor magnet 31, but the angle can be changed as appropriate. In the above-described embodiment, the sensor magnet 32 is shown in which the magnetic pole 32N is magnetized at 300 ° and the magnetic pole 32S is magnetized at unequal pitches at 60 °, but the angle can be changed as appropriate.

DESCRIPTION OF SYMBOLS 1a, 1b Wiper arm 2a, 2b Wiper blade 3 Windshield 4a, 4b Wiper shaft 5 Wiping range 6a, 6b Electric motor 7 Motor body 8 Deceleration mechanism 10a, 10b Wiper control device (control means)
11 ECU
12 In-vehicle LAN
13 Communication Line 14 First Sensor Unit 15 Second Sensor Unit 21 CPU
22 Data transceiver 23 ROM
24 RAM
25 blade position detection unit 26 blade stop position determination unit 27 blade order determination unit 28 motor lock determination unit 29 drive control instruction unit 31 first sensor magnet 32 second sensor magnet 32N magnetic pole 32S magnetic pole 33 rotor 34 rotating shaft 35 worm 36 worm wheel 37 first magnetic sensor 38 first magnetic sensor 39 second magnetic sensor 40 second magnetic sensor 41 sensor magnet 42 magnetic pole group 43 magnetic pole group 44 second magnetic sensor 45 second magnetic sensor S storage position L lower inversion position C central position PU Upper reverse position R Reset position U Upper reverse position CL Sensor magnet center line O Sensor magnet center

Claims (8)

Two wiper blades that perform a reciprocating wiping operation on the wiping surface;
An electric motor for reciprocating the wiper blade;
A wiper system having control means for controlling the operation of the electric motor,
The electric motor includes a rotation shaft, a reduction gear that meshes with a gear portion formed on the rotation shaft, a first sensor unit that outputs a signal along with the rotation of the rotation shaft, and the rotation of the reduction gear. And a second sensor unit that outputs a signal,
The first sensor unit includes a first sensor magnet attached to the rotating shaft, and a first magnetic sensor that outputs a predetermined signal along with the rotation of the first sensor magnet,
The second sensor unit includes a second sensor magnet attached to the reduction gear, and a second magnetic sensor that outputs a predetermined signal along with the rotation of the second sensor magnet,
The first sensor magnet is formed in a ring shape, a plurality of magnetic poles are arranged along the circumferential direction, and rotates with the rotating shaft,
The first magnetic sensor is disposed to face the first sensor magnet, and outputs a pulse signal in accordance with a change in polarity of the magnetic pole of the opposed first sensor magnet.
Said second sensor magnet is formed in a disk shape, it said rotates with the reduction gear, is arranged poles at unequal pitches in the circumferential direction has Rutotomoni, two pole group provided axisymmetrically In the magnetic pole group, a plurality of magnetic poles are alternately arranged at unequal pitches so that the magnetic pole width gradually decreases.
Two of the second magnetic sensors are arranged symmetrically at positions spaced 180 ° along the circumferential direction of the second sensor magnet so as to face the second sensor magnet, and the magnetic poles of the second sensor magnet facing each other. Outputs different signals depending on the polarity of
The control means detects an area where the wiper blade is present on the wiping surface based on a difference in switching time of the magnetic poles of the second sensor magnet detected by the two second magnetic sensors. Characteristic wiper system. The wiper system according to claim 1, wherein
The two wiper blades are arranged to face the wiping surface, and the wiping area of the wiper blade is divided into four areas .
The wiper system according to claim 1 , wherein the control means detects in which of the four areas the wiper blade is present. The wiper system according to claim 2, wherein
The control means detects, for the two wiper blades, a front-rear relationship of the wiper blades based on the areas where the wiper blades are detected to be present, and determines whether or not the wiper blades are replaced. Wiper system characterized by The wiper system according to claim 3.
When it is detected that the two wiper blades are present in the same area, the control means operates the wiper blade in the upward reverse position direction, and when the electric motor is locked, the wiper blade The wiper system determines that the wiper blades have come into contact with each other by switching, and causes the wiper blade on the following side to move forward in the normal control and operate in the direction of the upper reversal position. The wiper system according to claim 3.
When the wiper blade replacement is detected on the basis of the area where the wiper blade is present, the control means causes the wiper blade on the following side to precede the wiper blade in the upper reversal position direction during normal control. Wiper system characterized by being actuated toward. The wiper system according to claim 3.
When the wiper blade is present in the area where the wiper blades do not interfere with each other even when the replacement of the wiper blade is detected based on the area where the wiper blade exists. Is a wiper system in which the wiper blades are operated toward the upper reversal position in the same order as in normal control. The wiper system according to claim 1 , wherein
The wiper system, wherein the control means detects a difference in switching time of the magnetic poles using a pulse signal output from the first magnetic sensor while the magnetic poles of the second sensor magnets are switched. The wiper system according to claim 1 or 7 ,
The control means calculates the rotation angle of the second sensor magnet by multiplying the difference in magnetic pole switching time of the second sensor magnet by a predetermined angle calculation coefficient, and detects the position of the wiper blade. Wiper system

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