Wiping device

Abstract

To provide a wiping device capable of reducing the impact of communication delay in synchronous drive of a pair of motors in comparison to conventional techniques.SOLUTION: A wiping device includes a pair of drive units that individually drives a pair of wiper blades by using a pair of motors, and synchronously drives the pair of motors by transmitting and receiving rotational angle information indicating the rotational angles of the motors via a predetermined dedicated communication line between the pair of drive units. The pair of drive units sequentially acquires rotational angles at predetermined intervals, and transmits and receives, as the rotational angle information, the transmission rotational angle calculated by adding the latest rotational angle to the difference between the latest rotational angle and the previous rotational angle.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a wiping device.

Background Art

[0002] Patent Document 1 below discloses a wiper device capable of easily and surely setting control information. This wiper device includes a DR-side wiper blade driven by one motor and an AS-side wiper blade driven by the other motor. The pair of motors are driven and controlled by individual control microcomputers, and the pair of control microcomputers are connected by a communication line.

[0003] Further, in this wiper device, AS-side control information is stored in one control microcomputer. When there is no control information on the AS side or when the control information on the AS side does not correspond to the control information on the DR side, etc., when a predetermined control information setting condition is satisfied, the AS-side control information stored on the DR side is transmitted to the other control microcomputer via the communication line, and the other control microcomputer that has received this sets the control information on the AS side using the received control information.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, in such a wiper device (wiping device) according to the background art, a pair of control microcomputers (control devices) transmit and receive control information via a communication line to achieve synchronous control (synchronous driving) of a pair of motors. Therefore, an inevitable delay (communication delay) occurs in the acquisition of control information in the control device. This communication delay may reduce the driving accuracy in the synchronous driving of the pair of motors.

[0006] The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a wiping device capable of reducing the influence of communication delay in the synchronous driving of a pair of motors more than before.

Means for Solving the Problems

[0007] In order to achieve the above object, in the present invention, as a first solution means related to the wiping device, a pair of drive units for individually driving a pair of wiper blades by using a pair of motors is provided, and the pair of drive units transmits and receives rotation angle information regarding the rotation angle of the motor by using a predetermined dedicated communication line, thereby synchronously driving the pair of motors. The pair of drive units sequentially acquires the rotation angle at a predetermined cycle, and transmits and receives, as the rotation angle information, a transmission rotation angle obtained by adding the latest rotation angle to the difference between the latest rotation angle and the previous rotation angle.

[0008] In the present invention, as a second solution means related to the wiping device, in the above first solution means, when an abnormality occurs in the wired communication via the normal communication line, the pair of drive units transmits and receives the rotation angle information via the dedicated communication line.

[0009] In the present invention, as a third solution means related to the wiping device, in the above first or second solution means, one of the drive units drives the wiper blade provided on the driver's seat side of the vehicle among the pair of wiper blades, and the other drive unit drives the wiper blade provided on the passenger seat side of the vehicle.

[0010] In the present invention, as a fourth solution means related to the wiping device, in the above first or second solution means, the pair of drive units drives the pair of wiper blades in a symmetrical manner.

[0011] In the present invention, as a fifth solution means related to the wiping device, in the above first or second solution means, a means is adopted in which the pair of drive units drive the pair of wiper blades in a tandem manner.

Advantages of the Invention

[0012] According to the present invention, it is possible to provide a wiping device capable of reducing the influence of communication delay in the synchronous drive of a pair of motors more than before.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0014] An embodiment of the present invention will be described with reference to FIGS. 1 to 5. The wiping device A according to this embodiment is mounted on various vehicles such as gasoline vehicles, hybrid vehicles, or electric vehicles, and is a device for wiping rainwater adhering to the surface (wiping surface) of a wiping member such as a front glass or a rear glass.

[0015] As shown in FIG. 1, this wiping device A drives a pair of wiper blades 1d and 1p in a symmetrical (opposing) manner. The pair of wiper blades 1d and 1p are rod-shaped members placed on the front glass W as shown in the drawing. The pair of wiper blades 1d and 1p are in contact with the surface (wiping surface) of the front glass W, and wipe the rainwater on the front glass W by reciprocating (oscillating) on the wiping surface.

[0016] In FIG. 1, reference sign Rd is the wiping range of the wiper blade 1d on the driver's seat side, and reference sign Rp is the wiping range of the wiper blade 1p on the passenger seat side. The wiping range Rd on the driver's seat side extends from the lower inversion position to the upper inversion position of the wiper blade 1d, and is the moving range of the wiper blade 1d with the first wiper shaft 2d provided on the driver's seat side as the rotation axis.

[0017] On the other hand, the wiping range Rp on the passenger seat side extends from the lower inversion position to the upper inversion position of the wiper blade 1p, and is the moving range of the wiper blade 1p with the second wiper shaft 2p provided on the passenger seat side as the rotation axis. Such a wiping range Rd on the driver's seat side and a wiping range Rp on the passenger seat side are partial regions on the surface (wiping surface) of the front glass W.

[0018] The pair of wiper blades 1d and 1p temporarily stop at the lower inversion position and the upper inversion position during the reciprocating motion within the wiping ranges Rd and Rp. Specifically, when the pair of wiper blades 1d and 1p move from the lower inversion position toward the upper inversion position, they temporarily stop at the upper inversion position, and after this stop, they move from the upper inversion position toward the lower inversion position.

[0019] Also, the pair of wiper blades 1d and 1p temporarily stop at the lower inversion position, and after this stop, they move from the lower inversion position toward the upper inversion position. That is, the pair of wiper blades 1d and 1p in this embodiment repeat the reciprocating motion while temporarily stopping at the lower inversion position and the upper inversion position.

[0020] As shown in Fig. 1, such a wiping device A includes a pair of wiper motor units 3d and 3p that individually drive a pair of wiper blades 1d and 1p. These pair of wiper motor units 3d and 3p correspond to the pair of drive units in the present invention.

[0021] The pair of wiper motor units 3d and 3p are drive units that individually drive a pair of wiper blades 1d and 1p, and reciprocate the pair of wiper blades 1d and 1p in opposite directions facing each other. That is, the wiping device A according to the present embodiment is a device that drives a pair of wiper blades 1d and 1p in a symmetrical manner (opposing type).

[0022] Among the pair of wiper motor units 3d and 3p, the first wiper motor unit 3d (one of the drive units) is a drive device that drives a wiper blade 1d (one of the wiper blades) provided on the driver's seat side of the vehicle. The second wiper motor unit 3p (the other drive unit) is a drive device that drives a wiper blade 1p (the other wiper blade) provided on the passenger seat side of the vehicle.

[0023] The wiping device A according to the present embodiment has a connection structure shown in Fig. 2. That is, when viewed as a connection structure, the wiping device A includes, in addition to the pair of wiper motor units 3d and 3p, a control unit 4 (BCM), a vehicle battery 5, a main power cable 6, three fuses 7 to 9, three branch power cables 10 to 12, a first communication cable 13, a second communication cable 14, and a third communication cable 15.

[0024] The pair of wiper motor units 3d and 3p and the control unit 4 each include a first terminal, a second terminal, a third terminal, and a fourth terminal as components related to the connection structure. Among these first terminal, second terminal, third terminal, and fourth terminal, the first terminal is a power supply terminal connected to the power supply. The second terminal and the third terminal are the first and second communication terminals used for wired communication. The fourth terminal is a GND terminal connected to the ground potential (GND).

[0025] Of the pair of wiper motor units 3d and 3p, for the first wiper motor unit 3d, the first terminal (power supply terminal) is connected to the second branched power cable 11. Also, for the first wiper motor unit 3d, the second terminal (first communication terminal) is connected to the first communication cable 13, and the third terminal (second communication terminal) is connected to the third communication cable 15. Further, for the first wiper motor unit 3d, the fourth terminal (GND terminal) is connected to the reference potential (GND).

[0026] Such a first wiper motor unit 3d performs wired communication with the control unit 4 using the second terminal (first communication terminal), and performs wired communication with the second wiper motor unit 3p using the third terminal (second communication terminal), thereby rotationally driving the first wiper shaft 2d to be synchronized with the second wiper shaft 2p.

[0027] On the other hand, for the second wiper motor unit 3p, the first terminal (power supply terminal) is connected to the third branched power cable 12. Also, for the second wiper motor unit 3p, the second terminal (first communication terminal) is connected to the second communication cable 14, and the third terminal (second communication terminal) is connected to the third communication cable 15. Further, for the second wiper motor unit 3p, the fourth terminal (GND terminal) is connected to the reference potential (GND).

[0028] Such a second wiper motor unit 3p performs wired communication with the control unit 4 using the second terminal (first communication terminal), and performs wired communication with the first wiper motor unit 3d using the third terminal (second communication terminal), thereby rotationally driving the second wiper shaft 2p to be synchronized with the first wiper shaft 2d.

[0029] For the control unit 4, the first terminal (power supply terminal) is connected to the first branched power cable 10. Also, for the control unit 4, the second terminal (first communication terminal) is connected to the first communication cable 13, and the third terminal (second communication terminal) is connected to the second communication cable 14. Further, for this control unit 4, the fourth terminal (GND terminal) is connected to the reference potential (GND).

[0030] Such a control unit 4 synchronously drives the first wiper motor unit 3d and the second wiper motor unit 3p by transmitting predetermined control information (control commands) from the second terminal (first communication terminal) and the third terminal (second communication terminal) to the first wiper motor unit 3d and the second wiper motor unit 3p.

[0031] As shown in the figure, for the vehicle battery 5, the positive electrode is connected to one end of the main power cable 6, and the negative electrode is connected to the reference potential (GND). This vehicle battery 5 is the main power source (voltage source) of the vehicle that outputs DC power of a predetermined voltage, and supplies DC power to the first wiper motor unit 3d, the second wiper motor unit 3p, and the control unit 4 via the main power cable 6, three fuses 7-9, and three branch power cables 10-12.

[0032] As shown in the figure, one end of the main power cable 6 is connected to the positive electrode of the vehicle battery 5, and the other end is commonly connected to each one end of the three branch power cables 10-12. The main power cable 6 transmits the DC power supplied from the positive terminal of the vehicle battery 5 to the three branch power cables 10-12.

[0033] Among the three fuses 7-9, the first fuse 7 is provided at an intermediate position of the first branch power cable 10 as shown in the figure. One end of the first fuse 7 is connected to the other end side of the main power cable 6, and the other end is connected to the first terminal side of the control unit 4. Such a first fuse 7 blows when an abnormally large current is passed through the first branch power cable 10, cutting off the supply of DC power to the control unit 4.

[0034] The second fuse 8 is provided at an intermediate position of the second branch power cable 11 as shown in the figure. One end of the second fuse 8 is connected to the other end side of the main power cable 6, and the other end is connected to the first terminal side of the first wiper motor unit 3d. Such a second fuse 8 blows when an abnormally large current is passed through the second branch power cable 11, cutting off the supply of DC power to the first wiper motor unit 3d.

[0035] The third fuse 9 is provided at an intermediate portion of the third branched power cable 12 as shown in the figure. One end of the third fuse 9 is connected to the other end side of the main power cable 6, and the other end is connected to the first terminal side of the second wiper motor unit 3p. When an abnormally large current is applied to the third branched power cable 12, such a third fuse 9 blows to cut off the supply of DC power to the second wiper motor unit 3p.

[0036] Among the three branched power cables 10 to 12, one end of the first branched power cable 10 is connected to the other end of the power cable 6, and the other end is connected to the first terminal of the control unit 4. The first branched power cable 10 is a power line for supplying the DC power output from the vehicle battery 5 to the control unit 4.

[0037] One end of the second branched power cable 11 is connected to the other end of the power cable 6, and the other end is connected to the first terminal of the first wiper motor unit 3d. The second branched power cable 11 is a power line for supplying the DC power output from the vehicle battery 5 to the first wiper motor unit 3d.

[0038] One end of the third branched power cable 12 is connected to the other end of the power cable 6, and the other end is connected to the first terminal of the second wiper motor unit 3p. The third branched power cable 12 is a power line for supplying the DC power output from the vehicle battery 5 to the second wiper motor unit 3p.

[0039] As shown in the figure, one end of the first communication cable 13 is connected to the second terminal of the control unit 4, and the other end is connected to the second terminal of the first wiper motor unit 3d. The first communication cable 13 is a signal line that mediates wired communication between the control unit 4 and the first wiper motor unit 3d, and transmits a communication signal of the first method.

[0040] The first method described above is, for example, an in-vehicle LAN (Local Area Network). That is, the control unit 4 and the second wiper motor unit 3p transmit and receive communication signals conforming to the in-vehicle LAN, namely LIN signals, via the first communication cable 13.

[0041] One end of the second communication cable 14 is connected to the third terminal of the control unit 4, and the other end is connected to the second terminal of the second wiper motor unit 3p. The second communication cable 14 is a signal line that mediates wired communication between the control unit 4 and the second wiper motor unit 3p, and transmits the communication signal of the first method in the same manner as the first communication cable 13.

[0042] That is, the control unit 4 and the second wiper motor unit 3p transmit and receive LIN signals conforming to the in-vehicle LAN (Local Area Network) via the second communication cable 14, in the same manner as the control unit 4 and the first wiper motor unit 3d. Note that such first communication cable 13 and second communication cable 14 are the first normal communication line and the second normal communication line in this embodiment.

[0043] One end of the third communication cable 15 is connected to the third terminal of the first wiper motor unit 3d, and the other end is connected to the third terminal of the second wiper motor unit 3p. The third communication cable 15 is a signal line that mediates wired communication between the first wiper motor unit 3d and the second wiper motor unit 3p, and transmits a communication signal (CLN signal) of a second method different from the first method.

[0044] Such a third communication cable 15 is a dedicated communication line unique to the first wiper motor unit 3d and the second wiper motor unit 3p. Therefore, the second method is a communication method different from the in-vehicle LAN. The first wiper motor unit 3d and the second wiper motor unit 3p transmit and receive control information necessary for synchronous driving of a pair of wiper shafts 2d, 2p, that is, control information necessary for synchronous driving of a pair of wiper blades 1d, 1p, by using the third communication cable 15.

[0045] Note that the wired communication between the first wiper motor unit 3d and the second wiper motor unit 3p using the third communication cable 15 is an abnormal-time communication that is performed only when an abnormality occurs in the wired communication using the first communication cable 13 between the control unit 4 and the first wiper motor unit 3d or the wired communication using the second communication cable 14 between the control unit 4 and the second wiper motor unit 3p.

[0046] That is, when the wired communication (normal communication) compliant with the in-vehicle LAN using the first communication cable 13 and the second communication cable 14 is normal, the wiping device A does not perform the abnormal-time communication using the third communication cable 15. During normal times, the wiping device A reciprocates the pair of wiper blades 1d and 1p based solely on the wired communication between the control unit 4 compliant with the in-vehicle LAN and the first wiper motor unit 3d and the wired communication between the control unit 4 and the second wiper motor unit 3p.

[0047] Here, the pair of wiper motor units 3d, 3p and the control unit 4 will be described in more detail. As shown in FIG. 2, the first wiper motor unit 3d includes the first motor 31d, the first drive circuit 32d, and the first communication circuit 33d as functional components. Also, as shown in FIG. 2, the second wiper motor unit 3p includes the second motor 31p, the second drive circuit 32p, and the second communication circuit 33p as functional components.

[0048] In the first wiper motor unit 3d, the first motor 31d is a power source that reciprocates the first wiper blade 1d provided on the driver's seat side by rotationally driving the first wiper shaft 2d. This first motor 31d rotates at a rotational speed corresponding to the first drive signal input from the first drive circuit 32d.

[0049] The first drive circuit 32d generates the first drive signal based on the control information (control command) input from the first communication circuit 33d and the signal indicating the rotation angle (rotation angle information) input from the first motor 31d. That is, the first drive circuit 32d performs feedback control on the first motor 31d based on the control information (control command) of the control unit 4 and the rotation angle information of the first motor 31d.

[0050] The first communication circuit 33d is connected to the second terminal and the third terminal, acquires control information (control command) by performing wired communication with the control unit 4, and acquires the information (synchronization information) necessary to synchronize the first motor 31d with the second motor 31p by performing wired communication with the second wiper motor unit 3p.

[0051] Also, when the wired communication (normal communication) with the control unit 4 using the second terminal, that is, the first communication cable 13, becomes abnormal, the first communication circuit 33d performs wired communication (communication during abnormality) with the second wiper motor unit 3p using the third terminal, that is, the third communication cable 15, to acquire the synchronization information. That is, when the wired communication (normal communication) with the control unit 4 is normal, the first communication circuit 33d does not perform wired communication (communication during abnormality) with the second wiper motor unit 3p using the third terminal.

[0052] On the other hand, in the second wiper motor unit 3p, the second motor 31p is a power source that reciprocates the second wiper blade 1p provided on the passenger seat side by rotating the second wiper shaft 2p. This second motor 31p rotates at a rotational speed corresponding to the second drive signal input from the second drive circuit 32p.

[0053] The second drive circuit 32p generates the second drive signal based on the control information (control command) input from the second communication circuit 33p and the signal indicating the rotation angle (rotation angle information) input from the second motor 31p. That is, the second drive circuit 32p performs feedback control on the second motor 31p based on the control information (control command) of the control unit 4 and the rotation angle information of the second motor 31p.

[0054] The second communication circuit 33p is connected to the second terminal and the third terminal, obtains control information (control commands) by performing wired communication with the control unit 4, and obtains information (synchronization information) necessary to synchronize the second motor 31p with the first motor 31d by performing wired communication with the first wiper motor unit 3d.

[0055] Note that when the wired communication (normal communication) with the control unit 4 using the second terminal, that is, the second communication cable 14, malfunctions, the second communication circuit 33p performs wired communication (communication during abnormality) with the first wiper motor unit 3d using the third terminal, that is, the third communication cable 15, to obtain the above synchronization information. That is, when the wired communication (normal communication) with the control unit 4 is normal, the second communication circuit 33p does not perform wired communication (communication during abnormality) with the first wiper motor unit 3d using the third terminal.

[0056] When the wired communication (normal communication) with the control unit 4 using the first communication cable 13 and the second communication cable 14 malfunctions, such a pair of wiper motor units 3d, 3p transmits and receives rotation angle information regarding the pair of motors 31d, 31p using the third communication cable 15 by the pair of communication circuits 33d, 33p as the above synchronization information.

[0057] That is, when normal communication malfunctions, the pair of wiper motor units 3d, 3p grasps the rotation angles of the pair of motors 31d, 31p based on the rotation angle information obtained by communication during abnormality. Further, the pair of wiper motor units 3d, 3p synchronously drives the pair of motors 31d, 31p based on the rotation angle information thus obtained.

[0058] Here, the rotation angle information in this embodiment will be described. As shown in FIG. 3, a pair of wiper motor units 3d and 3p sequentially acquire the rotation angles M0, M1, ……, Mn-1, Mn of a pair of motors 31d and 31p at a plurality of times t0, t1, ……, tn-1, tn. That is, the pair of wiper motor units 3d and 3p sequentially acquire the rotation angles M0, M1, ……, Mn-1, Mn of the pair of motors 31d and 31p at a preset predetermined period (constant period).

[0059] Further, for a plurality of rotation angles M0, M1, ……, Mn-1, Mn acquired in time series, the pair of wiper motor units 3d and 3p calculate the difference Δm between the latest (current) rotation angle Mn and the previous rotation angle Mn-1, and use the value obtained by adding the latest (current) rotation angle Mn to the difference Δm as the transmission rotation angle Mt. The pair of wiper motor units 3d and 3p transmit and receive such a transmission rotation angle Mt as rotation angle information regarding the pair of motors 31d and 31p.

[0060] For example, when the pair of wiper motor units 3d and 3p acquire the latest (current) rotation angle M2 at the latest (current) time t2, they calculate the difference Δm21 between the latest (current) rotation angle M2 and the previous rotation angle M1 acquired at the previous time t1. The pair of wiper motor units 3d and 3p use the value obtained by adding this difference Δm21 to the latest (current) rotation angle M2 as the transmission rotation angle Mt.

[0061] Also, for example, when the pair of wiper motor units 3d and 3p acquire the latest (current) rotation angle M5 at the latest (current) time t5, they calculate the difference Δm54 between the latest (current) rotation angle M5 and the previous rotation angle M4 acquired at the previous time t4. The pair of wiper motor units 3d and 3p use the value obtained by adding this difference Δm54 to the latest (current) rotation angle M5 as the transmission rotation angle Mt.

[0062] The control unit 4 in the present embodiment is, for example, a one-chip microcomputer, and includes at least a storage unit, an arithmetic unit, and a communication unit as functional components. The storage unit stores in advance a predetermined wiper control program (application program). The arithmetic unit generates a control signal by executing the wiper control program. The communication unit transmits the control signal to the first wiper motor unit 3d and the second wiper motor unit 3p.

[0063] That is, the control unit 4 is a software control device that synchronously controls the first wiper motor unit 3d and the second wiper motor unit 3p by the cooperation of hardware resources and software resources. By synchronously controlling the first wiper motor unit 3d and the second wiper motor unit 3p, the control unit 4 controls the reciprocating movement of the pair of wiper blades 1d, 1p, that is, the wiping operation of the surface (wiped surface) of the front glass W.

[0064] Next, the operation of the wiping device A according to the present embodiment will be described with reference to the flowcharts shown in FIGS. 4 and 5.

[0065] When the wired communication using the normal communication lines, that is, the first communication cable 13 and the second communication cable 14, is normal, the wiping device A according to the present embodiment normally wipes the surface (wiped surface) of the front glass W. That is, during normal times, the wiping device A performs normal wiping on the surface (wiped surface) of the front glass W based on the wired communication between the control unit 4 and the first wiper motor unit 3d using the first communication cable 13 and the wired communication between the control unit 4 and the second wiper motor unit 3p using the second communication cable 14.

[0066] More specifically, the control unit 4 transmits a control signal to the first wiper motor unit 3d via the first communication cable 13. Further, the control unit 4 transmits a control signal to the second wiper motor unit 3p via the second communication cable 14. By supplying control signals from the control unit 4 to the first wiper motor unit 3d and the second wiper motor unit 3p respectively, the first wiper motor unit 3d and the second wiper motor unit 3p synchronously drive a pair of wiper blades 1d, 1p.

[0067] By this synchronous drive, the pair of wiper blades 1d, 1p reciprocate in a synchronized state on the surface (the surface to be wiped) of the front glass W. Then, due to the reciprocating motion of these pair of wiper blades 1d, 1p, the rainwater adhering to the surface (the surface to be wiped) of the front glass W is wiped off from the said surface to be wiped.

[0068] On the other hand, the first wiper motor unit 3d and the second wiper motor unit 3p regularly monitor the soundness of the wired communication with the control unit 4 using normal communication lines (the first communication cable 13 and the second communication cable 14). And when the first wiper motor unit 3d and the second wiper motor unit 3p determine that a communication abnormality has occurred, they perform wiping in case of abnormality by using a dedicated communication line, that is, the third communication cable 15.

[0069] For example, when the wired communication between the first wiper motor unit 3d and the control unit 4 via the second communication cable 14 becomes abnormal, the first wiper motor unit 3d obtains the rotation angle information of the second motor 31p from the second wiper motor unit 3p by using the third communication cable 15. Then, based on this rotation angle information, it drives the wiper blade 1d on the driver's seat side to synchronize with the wiper blade 1p on the passenger seat side.

[0070] Further, when the wired communication between the second wiper motor unit 3p and the control unit 4 via the first communication cable 13 becomes abnormal, the second wiper motor unit 3p acquires the rotation angle information of the first motor 31d from the first wiper motor unit 3d by using the third communication cable 15. Then, based on this rotation angle information, the wiper blade 1p on the passenger seat side is driven to be synchronized with the wiper blade 1d on the driver's seat side.

[0071] Here, the pair of wiper motor units 3d and 3p perform the processes shown in FIGS. 4 and 5 for the rotation angle information. The flowchart of FIG. 4 is the generation process of the rotation angle information in the first wiper motor unit 3d among the pair of wiper motor units 3d and 3p. Further, the flowchart of FIG. 5 is the control process of the second wiper motor unit 3p corresponding to FIG. 4.

[0072] When the second wiper motor unit 3p transmits the rotation angle information to the first wiper motor unit 3d, the second wiper motor unit 3p generates the rotation angle information according to the flowchart of FIG. 4. Also, in this case, the first wiper motor unit 3d performs the control process according to the flowchart of FIG. 5.

[0073] The first wiper motor unit 3d acquires the latest (current) rotation angle Mnd from the first motor 31d (step S1d). Then, the first wiper motor unit 3d determines whether the previous rotation angle Mn-1d is stored in its own memory (step S2d). When the determination in step S2d is "No", that is, when the previous rotation angle Mn-1d is not stored in the memory, the first wiper motor unit 3d sets the latest (current) rotation angle Mnd as the transmission rotation angle Mtd (step S3d).

[0074] On the one hand, when the determination in step S2d is "Yes", that is, when the previous rotation angle Mn-1d is stored in the memory, the first wiper motor unit 3d calculates the difference Δmd between the latest (current) rotation angle Mnd and the previous rotation angle Mn-1d (step S4d). Then, the first wiper motor unit 3d sets the value obtained by adding the latest (current) rotation angle Mnd to the above difference Δmd to the transmission rotation angle Mtd (step S5d).

[0075] Then, in preparation for the generation process of the rotation angle information at the next time, the first wiper motor unit 3d stores the latest (current) rotation angle Mnd obtained in step S1d in the memory (step S6d). Then, when the storage process in step S6d is completed, the first wiper motor unit 3d (the first communication circuit 33d) transmits and receives the transmission rotation angle Mtd as rotation angle information to and from the second wiper motor unit 3p (the second communication circuit 33p) (step S7d).

[0076] On the other hand, the second wiper motor unit 3p first obtains the latest (current) rotation angle Mnp from the second motor 31p (step S1p). Then, the second wiper motor unit 3p obtains the above-described transmission rotation angle Mtd (rotation angle information) from the first wiper motor unit 3d (step S2p).

[0077] When the process in step S2p is completed, the second wiper motor unit 3p calculates the difference Δmdp between the rotation angle Mnp related to the second motor 31p and the transmission rotation angle Mtd related to the first motor 31d (step S3p). Then, the second wiper motor unit 3p drives the second motor 31p so that the difference Δmdp becomes "zero", that is, so as to be synchronized with the first motor 31d.

[0078] Such a wiping device A includes a pair of drive units that individually drive a pair of wiper blades 1d and 1p by using a pair of motors 31d and 31p. A pair of wiper motor units 3d and 3p (drive units) transmit and receive rotation angle information regarding the rotation angles of the pair of motors 31d and 31p by using a predetermined first communication cable 13 (dedicated communication line), thereby synchronously driving the pair of motors 31d and 31p.

[0079] Also, in this wiping device A, the pair of wiper motor units 3d and 3p (drive units) sequentially acquire the rotation angles M0, M1, ……, Mn-1, Mn of the pair of motors 31d and 31p at a predetermined cycle, and transmit and receive, as rotation angle information, a transmission rotation angle Mt obtained by adding the latest rotation angle Mn to the difference Δm between the latest rotation angle Mn and the previous rotation angle Mn-1.

[0080] According to such a wiping device A, instead of transmitting and receiving the latest rotation angle Mn as rotation angle information, the transmission rotation angle Mt obtained by adding the difference Δm to the latest rotation angle Mn is transmitted and received as rotation angle information. Therefore, it is possible to synchronously drive the pair of motors 31d and 31p with the influence of communication delay reduced more than before. Thus, according to this wiping device A, it is possible to reduce the influence of communication delay and synchronously control the pair of wiper blades 1d and 1p.

[0081] Also, in this wiping device A, when an abnormality occurs in the wired communication via the first communication cable 13 (first normal communication line) or the wired communication via the second communication cable 14 (second normal communication line) for the first wiper motor unit 3d and the second wiper motor unit 3p (pair of drive units), signals necessary for synchronously driving the pair of wiper blades 1d and 1p are transmitted and received via the third communication cable 15 (dedicated communication line).

[0082] That is, according to the present embodiment, it is possible to reduce the influence of communication delay in the synchronous driving of the pair of motors 31d and 31p more than before during communication in case of an abnormality using the third communication cable 15 (dedicated communication line).

[0083] In this wiping device A, the first wiper motor unit 3d (one of the drive units) drives the wiper blade 1d provided on the driver's seat side of the vehicle among the pair of wiper blades 1d and 1p, and the second wiper motor unit 3p (the other drive unit) drives the wiper blade 1p provided on the passenger seat side of the vehicle.

[0084] Therefore, according to the present embodiment, in a vehicle in which the wiper blades 1d and 1p are respectively provided on the driver's seat side and the passenger seat side, it is possible to reduce the influence of communication delay in the synchronous driving of the pair of motors 31d and 31p more than before.

[0085] Furthermore, in the wiping device A according to the present embodiment, the first wiper motor unit 3d and the second wiper motor unit 3p (a pair of drive units) drive the pair of wiper blades 1d and 1p in a symmetrical manner. Therefore, according to the present embodiment, it is possible to reduce the influence of communication delay in the synchronous driving of the pair of motors 31d and 31p more than before while realizing the symmetrical driving of the pair of wiper blades 1d and 1p.

[0086] Note that the present invention is not limited to the above-described embodiment, and various modifications are possible. For example, in the above-described embodiment, the wiping device A that drives the pair of wiper blades 1d and 1p in a symmetrical manner (opposite manner) has been described, but the present invention is not limited thereto. The present invention is also applicable to a wiping device that drives the pair of wiper blades 1d and 1p in a tandem manner (parallel interlocking manner).

Explanation of Reference Numerals

[0087] A... Wiping device, 1d, 1p... Wiper blades, 2d, 2p... Wiper shafts, 3d... First wiper motor unit (drive unit), 3p... Second wiper motor unit (drive unit), 4... Control unit (BCM), 5... Vehicle battery, 6... Main power cable, 7 - 9... Fuses, 10 - 12... Branch power cables, 13... First communication cable, 14... Second communication cable, 15... Third communication cable

Claims

1. A wiping device comprising a pair of drive units that individually drive a pair of wiper blades by using a pair of motors, and the pair of drive units synchronously drive the pair of motors by transmitting and receiving rotation angle information regarding the rotation angle of the motors via a predetermined dedicated communication line, wherein the pair of drive units sequentially acquire the rotation angle at a predetermined period, and transmit and receive, as the rotation angle information, a transmission rotation angle obtained by adding the latest rotation angle to the difference between the latest rotation angle and the previous rotation angle.

2. The wiping device according to claim 1, wherein the pair of drive units transmit and receive the rotation angle information via the dedicated communication line when an abnormality occurs in the wired communication via a normal communication line.

3. One of the pair of drive units drives the wiper blade provided on the driver's seat side of the vehicle among the pair of wiper blades, and the other drive unit drives the wiper blade provided on the passenger seat side of the vehicle. The wiping device according to claim 1 or 2.

4. The wiping device according to claim 1 or 2, wherein the pair of drive units drive the pair of wiper blades in a symmetrical manner.

5. The wiping device according to claim 1 or 2, wherein the pair of drive units drive the pair of wiper blades in a tandem manner.

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