Wipe device

Abstract

To provide a wipe device which can appropriately estimate a load condition of a drive circuit before and after switching a wipe range.SOLUTION: A wipe device which uses a predetermined power source to reciprocatingly move a wiper blade to wipe rain water on a surface to be wiped, includes a drive circuit which drives the power source, and a control part which controls the drive circuit. The control part controls an evaluation period of load information of the drive circuit to be set depending on a wipe range.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Patent Document 1 discloses a vehicle wiper control device that selectively and intensively wipes away dirt and the like. This vehicle wiper control device includes a DC motor device for causing a wiper blade member to slide back and forth along the surface of a car window glass member, a motor rotation control means for controlling the rotation of the DC motor device, a power supply line arranged in a bridge circuit for supplying power to the DC motor device, a current detection means for detecting a current flowing through the power supply line while the wiper blade member slides, and a current displacement detection means for detecting whether the displacement amount per unit time of the detection value by the current detection means exceeds a predetermined threshold value, and the motor rotation control means switches the rotation direction of the DC motor device so that the wiper blade member repeatedly slides over the portion detected by the current displacement detection means.

[0003] According to this vehicle wiper control device, the rotation direction of the DC motor device is switched between forward and reverse so that the wiper blade member repeatedly slides over the detection portion of the current displacement detection means, making it possible to selectively and intensively wipe away only the dirt and other particles adhering to the car window glass member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2005-082104 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the above-mentioned background art, the wiping range of the wiper blade (wiper blade member) is narrowed and the wiping speed of the wiper blade is increased, so that the dirt and the like are selectively and intensively wiped away. In controlling the switching of the wiping range, it is necessary to estimate the load state of the drive circuit that drives the motor (DC motor device) so as not to place an excessive load on the drive circuit.

[0006] In order to estimate the load state, it is necessary to acquire load information such as the drive power and the motor rotation speed at a predetermined timing before and after switching the wiping range. However, if the timing for acquiring the load information is not appropriately set, there is a problem that the load state of the drive circuit cannot be appropriately estimated.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and has an object to provide a wiping device that is capable of appropriately estimating the load state of a drive circuit before and after switching of the wiping range. [Means for solving the problem]

[0008] In order to achieve the above-mentioned object, the present invention adopts, as a first solution relating to a wiping device, a wiping device that wipes rainwater from a surface to be wiped by reciprocating a wiper blade using a predetermined power source and switches the wiping range of the wiper blade between a normal wiping range and a narrow wiping range narrower than the normal wiping range, the wiping device comprising a drive circuit that drives the power source and a control unit that controls the drive circuit, and the control unit sets an evaluation period for load information of the drive circuit based on the normal wiping range and the narrow wiping range.

[0009] In the present invention, as a second solution related to the wiping device, the first solution described above is achieved by adopting a means in which, when switching between the normal wiping range corresponding to the normal mode and the narrow wiping range corresponding to the heavy rain mode, the control unit sets the evaluation period for the heavy rain mode based on the ratio between the normal wiping range and the narrow wiping range.

[0010] The present invention adopts a third solution related to the wiping device, which is the second solution described above, in which the narrow wiping range is such that the upper reversal position of the wiper blade is the same as the normal wiping range, and the lower reversal position of the wiper blade is higher than the normal wiping range.

[0011] The present invention employs, as a fourth solving means related to the wiping device, any one of the first to third solving means described above, a means in which the power source simultaneously reciprocates a pair of the wiper blades.

[0012] The present invention adopts a fifth solution relating to a wiping device, in which, in any of the first to third solutions described above, the power source is provided in a pair, and of the pair of wiper blades, the power source reciprocates the wiper blade corresponding to itself. Effect of the Invention

[0013] According to the present invention, it is possible to provide a wiping device capable of appropriately estimating the load state of a drive circuit before and after switching of the wiping range. [Brief description of the drawings]

[0014] [Figure 1] 1 is a block diagram showing a functional configuration of a wiping device according to a first embodiment of the present invention. [Diagram 2] 4 is a first flowchart showing the operation of the wiping device according to the first embodiment of the present invention. [Diagram 3] 5 is a waveform diagram showing the operation of the wiping device according to the first embodiment of the present invention. FIG. [Figure 4] 5A to 5C are reference views relating to the operation of the wiping device according to the first embodiment of the present invention. [Diagram 5] FIG. 6 is a block diagram showing a functional configuration of a wiping device according to a second embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] [First embodiment] First, a first embodiment of the present invention will be described with reference to Figures 1 to 4. A wiping device A according to the first embodiment is mounted on various types of mobile vehicles such as a gasoline-powered automobile, a hybrid automobile, or an electric automobile, and is a device for wiping rainwater adhering to the surface (wiped surface W) of a member to be wiped such as a windshield or a rear window.

[0016] 1, the wiping device A according to the first embodiment includes a pair of wiper blades 1d, 1p, a pair of wiper arms 2d, 2p, a link mechanism 3, a motor 4, an angle detection circuit 5, a control unit 6, and a drive circuit 7. In addition, the control unit 6 includes a ROM (Read Only Memory) 61, a RAM (Random Access Memory) 62, and a CPU (Central Processing Unit) 63 as shown in the figure.

[0017] This wiping device A employs a single motor drive system in which a pair of wiper blades 1d, 1p are driven by a single motor 4 (power source) by mechanically connecting a pair of wiper arms 2d, 2p with a link mechanism 3. In other words, this wiping device A is provided with one power source, which simultaneously reciprocates the pair of wiper blades 1d, 1p. In addition, this wiping device A employs a parallel wiping system in which the pair of wiper blades 1d, 1p move in the same direction, as shown in FIG. 1.

[0018] In Fig. 1, the letter "d" indicates a member or part related to the driver's side of the vehicle. The letter "p" indicates a member or part related to the passenger's side of the vehicle. In Fig. 1, the letter Rd indicates the wiping range of the wiper blade 1d on the driver's side when the operation mode of the wiping device A is set to the normal mode (driver's side normal wiping range). The letter Rp indicates the wiping range of the wiper blade 1p on the passenger's side when the operation mode is set to the normal mode (passenger's side normal wiping range).

[0019] The driver's side normal wiping range Rd is a range from the lower reversal position PLd to the upper reversal position PUd as the movement trajectory of the driver's side wiper blade 1d. The lower reversal position PLd is a position where the driver's side wiper blade 1d switches from a downward motion to an upward motion on the wiped surface W. The upper reversal position PUd is a position where the driver's side wiper blade 1d switches from an upward motion to a downward motion on the wiped surface W.

[0020] The passenger side normal wiping range Rp is a range extending from the lower reversal position PLp to the upper reversal position PUp as the movement trajectory of the passenger side wiper blade 1p. The lower reversal position PLp is a position where the passenger side wiper blade 1p switches from a downward motion to an upward motion on the wiped surface W. The upper reversal position PUp is a position where the passenger side wiper blade 1p switches from a downward motion to an upward motion on the wiped surface W. The driver side normal wiping range Rd and the passenger side normal wiping range Rp are normal wiping ranges corresponding to the normal mode.

[0021] Although details will be described later, this wiping device A has a heavy rain mode as an operation mode in addition to the normal mode. The normal mode is an operation mode corresponding to normal rainfall. In contrast, the heavy rain mode is an operation mode in which the wiping range is narrower than the driver's side normal wiping range Rd and the passenger side normal wiping range Rp in the normal mode. In other words, the heavy rain mode is an operation mode in which a wiping range (heavy rain wiping range) narrower than the driver's side normal wiping range Rd and the passenger side normal wiping range Rp in the normal mode is wiped, and the wiping speed (reciprocating speed of the pair of wiper blades 1d, 1p) is faster than in the normal mode.

[0022] For example, the heavy rain wiping range has an upper inversion position that is the same as the upper inversion positions PUd, PUp of the driver's side normal wiping range Rd and the passenger's side normal wiping range Rp, but a lower inversion position that is set to a position (lower inversion positions QLd, QLp) higher than the lower inversion positions PLd, PLp of the driver's side normal wiping range Rd and the passenger's side normal wiping range Rp. Such a heavy rain wiping range is, for example, the forward visibility "A zone" set by regulations, and corresponds to the narrow wiping range of the present invention.

[0023] Here, "A Zone" refers to the area equivalent to "A Area" in the wipe-out area regulations of Japan and the European Economic Community (EEC) and "C Area" in the wipe-out area regulations of the US Federal Motor Vehicle Safety Standards (FMVSS).

[0024] As shown in the figure, the pair of wiper blades 1d, 1p are rod-shaped members arranged on the surface to be wiped W. The pair of wiper blades 1d, 1p abut against the surface to be wiped W and wipe away rainwater present on the surface to be wiped by performing a reciprocating motion (oscillating motion) on the surface to be wiped W. The pair of wiper blades 1d, 1p is mechanically connected to a motor 4 via a pair of wiper arms 2d, 2p, etc.

[0025] That is, the wiper blade 1d on the driver's side is connected to the motor 4 via a wiper arm 2d provided on the driver's side. The wiper blade 1p on the passenger's side is connected to the motor 4 via a link mechanism 3 in addition to the wiper arm 2p provided on the passenger's side.

[0026] As shown in the figure, the pair of wiper arms 2d, 2p are rod-shaped members, one end of which is connected to the intermediate position of the pair of wiper blades 1d, 1p, and the other end of which is connected to the pair of wiper shafts Td, Tp. That is, the wiper arm 2d on the driver's seat side has one end connected to the intermediate position of the wiper blade 1d on the driver's seat side, and the other end connected to the wiper shaft Td on the driver's seat side.

[0027] On the other hand, one end of the passenger side wiper arm 2p is connected to the middle position of the passenger side wiper blade 1p, and the other end is connected to the passenger side wiper shaft Tp. Note that such a pair of wiper arms 2d, 2p are members included in the components of the pair of wiper blades 1d, 1p.

[0028] The pair of wiper arms 2d, 2p function as power transmission parts that mechanically transmit the rotational power of the motor 4 to the pair of wiper blades 1d, 1p. In addition, the pair of wiper arms 2d, 2p function as biasing members that press the pair of wiper blades 1d, 1p against the surface W to be wiped with a predetermined pressing force.

[0029] The link mechanism 3 is a mechanical component that interconnects the other ends of the pair of wiper arms 2d, 2p and is connected to the output shaft of the motor 4. The link mechanism 3 also has a pair of support shafts fixed to the vehicle and is rotatable around the support shafts. The output shaft of the motor 4 is connected to the link mechanism 3, and by manipulating the rotation angle of the link mechanism 3 around the support shafts, the pair of wiper blades 1d, 1p are swung on the surface to be wiped. The motor 4 is a predetermined power source in the first embodiment.

[0030] The angle detection circuit 5 outputs an angle signal proportional to the rotation angle of the motor 4 to the CPU 63. This angle signal is a signal indicating the operating angle of the pair of wiper blades 1d, 1p connected to the output shaft of the motor 4 via the link mechanism 3 or the like. In detail, such an angle signal is composed of a relative position signal indicating the relative position of the pair of wiper blades 1d, 1p and an absolute position signal indicating the absolute position of the pair of wiper blades 1d, 1p.

[0031] The relative position signal is a pulse signal (motor pulse) generated with the rotation of the motor 4, and is a pulse signal (pulse train) with a number of pulses proportional to the rotation angle of the motor 4. In contrast, the absolute position signal is a single pulse signal generated when the pair of wiper blades 1d, 1p reach a control reference position. The control reference position is, for example, the bottom reversal positions PLd, PLp.

[0032] The control unit 6 has two control modes corresponding to the above-mentioned operation modes (normal mode and heavy rain mode) of the wiping device A. The control unit 6 generates a drive command corresponding to the operation mode by carrying out a control process corresponding to the operation mode of the wiping device A. The control unit 6 outputs the drive command corresponding to the above-mentioned operation mode to the drive circuit 7, thereby controlling the movement of the pair of wiper blades 1d, 1p according to the operation mode.

[0033] Such a normal mode in the control unit 6 corresponds to the normal mode of the wiping device A, and is a control mode for the pair of wiper blades 1d, 1p for normal rainfall. When the normal mode is instructed by a switch signal input from a higher-level control device, the control unit 6 generates a drive command according to the normal mode and outputs it to the drive circuit 7. Note that the switch signal is a higher-level control command that instructs the wiping device A to turn on / off the wiper switch provided on the vehicle, specify heavy rain mode, turn on / off the mist switch, intermittent operation (Lo, Hi, INT), etc.

[0034] On the other hand, the heavy rain mode in the control unit 6 corresponds to the heavy rain mode of the wiping device A, and is a control mode for the pair of wiper blades 1d, 1p for sudden heavy rain. When the heavy rain mode is instructed by the switch signal, the control unit 6 generates a drive command according to the heavy rain mode and outputs it to the drive circuit 7.

[0035] In controlling the pair of wiper blades 1d, 1p, the control unit 6 refers to a switch signal input from a higher-level control device (ECU: Electronic Control Unit) and an angle signal input from the angle detection circuit 5. That is, the control unit 6 feedback-controls the pair of wiper blades 1d, 1p based on the switch signal and the angle signal.

[0036] In the control unit 6, the ROM 61 is a non-volatile memory capable of retaining stored data. The ROM 61 stores a control program executed by the CPU 63 to feedback control the pair of wiper blades 1d, 1p. The ROM 61 also stores a normal mode operation map and a heavy rain mode operation map required for the CPU 63 to execute the control program.

[0037] The normal mode operation map is a control map used when the CPU 63 executes control processing (normal control processing) related to the normal mode in the control program. That is, the normal mode operation map is a group of control data indicating the time-series target speeds of the pair of wiper blades 1d, 1p in the normal mode.

[0038] On the other hand, the heavy rain mode operation map is a control map used when the CPU 63 executes control processing related to the heavy rain mode (heavy rain control processing) in the control program. That is, the heavy rain mode operation map is a group of control data indicating the time-series target speeds of the pair of wiper blades 1d, 1p in the heavy rain mode.

[0039] The RAM 62 is a volatile memory that cannot retain stored data. This RAM 62 temporarily stores various data generated when the CPU 63 executes the control program. For example, this RAM 62 temporarily stores a flag (control flag F) indicating whether the control mode being executed is the normal mode or the heavy rain mode, a counter value (wiping count value N) indicating the number of wiping operations in the control mode being executed, and the like.

[0040] The CPU 63 generates a drive command by executing a control program pre-stored in the ROM 61, and outputs the drive command to the drive circuit 7. When executing the control program, the CPU 63 refers to a switch signal input from a higher-level control device (ECU), an angle signal input from the angle detection circuit 5, and also to a normal mode operation map and a heavy rain mode operation map pre-stored in the ROM 61.

[0041] That is, the CPU 63 generates a drive command by referring to the switch signal, the angle signal, and the normal mode operation map and the heavy rain mode operation map based on the control program. This drive command is a control command to instruct the drive circuit 7 to drive the pair of wiper blades 1d, 1p according to the control mode (normal mode or heavy rain mode). In addition, this drive command is a control command to move the pair of wiper blades 1d, 1p so that the moving speed of the pair of wiper blades 1d, 1p obtained from the angle signal becomes equal to the target speed indicated by the normal mode operation map or the heavy rain mode operation map.

[0042] The drive circuit 7 generates a drive signal based on a drive command input from the CPU 63 (controller 6) and outputs the drive signal to the motor 4. The drive circuit 7 is, for example, an inverter circuit including a plurality of switching transistors. When the drive circuit 7 is an inverter circuit, the drive command is a PWM (Pulse Width Modulation) signal whose duty ratio is variably set according to the deviation between the target speed and the moving speed of the pair of wiper blades 1d, 1p.

[0043] Here, the drive circuit 7 drives the motor 4 in accordance with a drive command input from the CPU 63, but it is assumed that the drive circuit 7 may fall into an overloaded state due to an abnormality in the relationship between the pair of wiper blades 1d, 1p and the surface to be wiped W or an abnormality in the motor 4. If this overloaded state continues, the drive circuit 7 may be damaged or may break down.

[0044] The CPU 63 executes a load condition estimation process for estimating the load condition of the drive circuit 7 based on a control program in order to protect the drive circuit 7 from an overload condition of the drive circuit 7. That is, the CPU 63 acquires information (load information) required for load estimation, such as a drive command and an angle signal, during a predetermined evaluation period preset by the control program, and estimates the load condition of the drive circuit 7 using this load information. The load information is an important physical quantity that determines the estimation accuracy of the load condition of the drive circuit 7.

[0045] Next, a characteristic operation (load state estimation process) of the wiping device A according to the first embodiment will be described with reference to the flowchart shown in Fig. 2. Note that this flowchart shows the procedure of the control process in the CPU 63 (control unit 6).

[0046] Before describing the characteristic operation of the wiping device A, a switching process of the operation mode in the wiping device A will be described. In this switching process, the CPU 63 recognizes the operation mode instructed by the upper control device (ECU) by referring to a switch signal input from the upper control device based on a control program. Then, the CPU 63 sets the operation mode to either the normal mode or the heavy rain mode alternatively based on the recognition result.

[0047] For example, when a normal mode is instructed from a higher-level control device, the CPU 63 reads out a normal mode operation map from the ROM 61 based on the control program. Then, the CPU 63 generates a drive command based on the normal mode operation map and the angle signal input from the angle detection circuit 5, and outputs the drive command to the drive circuit 7.

[0048] The drive circuit 7 generates a drive signal based on the drive command and supplies the drive signal to the motor 4 to reciprocate the pair of wiper blades 1d, 1p. That is, in the normal mode of the wiping device A, the pair of wiper blades 1d, 1p are feedback-controlled based on the normal mode operation map and the angle signal.

[0049] On the other hand, when the heavy rain mode is instructed from the upper control device, the CPU 63 reads out the heavy rain mode operation map from the ROM 61 based on the control program. Then, the CPU 63 generates a drive command based on the heavy rain mode operation map and the angle signal input from the angle detection circuit 5, and outputs the drive command to the drive circuit 7.

[0050] The drive circuit 7 generates a drive signal based on the drive command and supplies the drive signal to the motor 4 to reciprocate the pair of wiper blades 1d, 1p. That is, in the normal mode of the wiping device A, the pair of wiper blades 1d, 1p are feedback-controlled based on the heavy rain mode operation map and the angle signal.

[0051] In parallel with the feedback control (normal processing) of the pair of wiper blades 1d, 1p in the normal mode or the heavy rain mode, the CPU 63 executes a load condition estimation process shown in Fig. 2 at a predetermined timing. The CPU 63 recognizes the load condition of the drive circuit 7 by the load condition estimation process.

[0052] That is, the CPU 63 judges whether the normal processing currently being executed is normal processing for the heavy rain mode (step S1). If the judgment in step S1 is "No", the CPU 63 executes a normal load estimation calculation (calculation C1) (step S2). On the other hand, if the judgment in step S1 is "Yes", the CPU 63 executes a load estimation calculation with detection range correction (calculation C2) (step S3).

[0053] The details of the above calculations C1 and C2 will be described below with reference to Fig. 3. In Fig. 3, (a) shows the change over time of the working angle Dn of the pair of wiper blades 1d, 1p in the normal mode. Also, in Fig. 3, (b) shows the change over time of the working angle Dg of the pair of wiper blades 1d, 1p in the heavy rain mode.

[0054] As can be seen by comparing the range of the operating angle Dn in Figure 3(a) with the range of the operating angle Dg in Figure 3(a), the maximum operating angles in the normal mode and the heavy rain mode are the same (about 150°), but the minimum operating angles in the normal mode and the heavy rain mode are different. That is, the minimum operating angle in the normal mode is about 20°, while the minimum operating angle in the heavy rain mode is about 50°.

[0055] 3(a) and 3(b), the half period Hg of the pair of wiper blades 1d, 1p in the heavy rain mode is shorter than the half period Hn of the pair of wiper blades 1d, 1p in the normal mode. In other words, the reciprocating speed of the pair of wiper blades 1d, 1p in the heavy rain mode is faster than the reciprocating speed of the pair of wiper blades 1d, 1p in the normal mode.

[0056] 3 also shows a case where the duty ratios En, Eg (%) of the drive command and the rotation speeds Fn, Fg (rpm) of the motor 4 are acquired as load information required for load estimation of the drive circuit 7. The duty ratio (%) is a physical quantity that indicates the load state of the drive circuit 7 when the drive command is a PWM signal. The rotation speeds Fn, Fg are physical quantities obtained from the angle signal of the angle detection circuit 5.

[0057] Furthermore, the period Mn in Fig. 3(a) is a period for acquiring load information in the normal mode. That is, this period Mn is a period for evaluating load information (normal evaluation period) for the CPU 63 to estimate the load of the drive circuit 7 in the normal mode. On the other hand, the period Mg in Fig. 3(b) is a period for acquiring load information in the heavy rain mode. That is, this period Mg is a period for evaluating load information (heavy rain evaluation period) for the CPU 63 to estimate the load of the drive circuit 7 in the heavy rain mode.

[0058] The maximum operating angles in the normal mode and the heavy rain mode correspond to the upper inversion position PUd of the driver's side normal wiping range Rd and the upper inversion position PUp of the passenger side normal wiping range Rp. The minimum operating angle in the normal mode corresponds to the lower inversion position PLd of the driver's side normal wiping range Rd and the lower inversion position PLp of the passenger side normal wiping range Rp. The minimum operating angle in the heavy rain mode is the lower inversion position QLd, QLp that is set at a position higher than the lower inversion position PLd of the driver's side normal wiping range Rd and the lower inversion position PLp of the passenger side normal wiping range Rp.

[0059] Here, the operating angle corresponding to the maximum operating angle in the normal mode is defined as the upper reversal angle K1, the operating angle corresponding to the minimum operating angle in the normal mode is defined as the lower reversal angle K2, the operating angle corresponding to the upper side of the load estimation range in the normal mode is defined as the load estimation range upper angle K3, and the operating angle corresponding to the lower side of the load estimation range in the normal mode is defined as the load estimation range lower angle K4.

[0060] In addition, the operating angle corresponding to the maximum operating angle in the heavy rain mode is designated as the upper reversal angle K5, the operating angle corresponding to the minimum operating angle in the heavy rain mode is designated as the lower reversal angle K6, the operating angle corresponding to the upper side of the load estimation range in the heavy rain mode is designated as the upper load estimation range angle K7, and the operating angle corresponding to the lower side of the load estimation range in the heavy rain mode is designated as the lower load estimation range angle K8.

[0061] Each of these operating angles is a control parameter provided by a control program. Among these operating angles, the upper angle K7 of the load estimation range is given by substituting the upper reversal angle K1, the lower reversal angle K2, the lower angle K4 of the load estimation range, the upper reversal angle K5, and the lower reversal angle K6 into the following formula (1). K7=K6+(K4-K2)×(K5-K6)÷(K1-K2) (1)

[0062] In addition, the load estimation range lower angle K8 is obtained by substituting the upper reversal angle K1, the lower reversal angle K2, the load estimation range upper angle K3, the load estimation range lower angle K4, the upper reversal angle K5, the lower reversal angle K6, and the load estimation range upper angle K7 obtained by the above equation (1) into the below equation (2). K8=K7+(K3-K4)×(K5-K6)÷(K1-K2) (2)

[0063] The CPU 63 calculates the load estimation range upper angle K7 and the load estimation range lower angle K8 by using the above formulas (1) and (2) based on the control program. Then, the CPU 63 sets the difference between the load estimation range upper angle K7 and the load estimation range lower angle K8 as the evaluation period Mg of the load information of the drive circuit 7 in the heavy rain mode.

[0064] That is, the CPU 63 sets the evaluation period Mg of the load information of the drive circuit 7 in the heavy rain mode based on the wiping range of the pair of wiper blades 1d, 1p, that is, based on the normal wiping range in the normal mode and the heavy rain wiping range (narrow wiping range) in the heavy rain mode.

[0065] Figure 4 shows a case in which the evaluation period Mg for the load information of the drive circuit 7 in heavy rain mode is set without taking into account the change in the wiping range of a pair of wiper blades 1d, 1p due to switching of the operating mode, that is, the difference between the normal wiping range in normal mode and the heavy rain wiping range (narrow wiping range) in heavy rain mode, in relation to the method of setting the evaluation period Mg.

[0066] In this case, the difference between the normal wiping range in normal mode and the heavy rain wiping range (narrow wiping range) in heavy rain mode is not taken into account, so the evaluation period Mg in heavy rain mode is wider than the heavy rain wiping range (narrow wiping range).

[0067] In addition, this evaluation period Mg is adapted to obtain a region in which the duty ratio Eg in heavy rain mode is higher than the duty ratio En in normal mode, and the proportion of the acceleration region at the rotation speed Fg (rpm) of the motor 4 is higher than the proportion of the acceleration region at the rotation speed Fn (rpm) in normal mode.

[0068] Therefore, if the evaluation period Mg in heavy rain mode is set without taking into account the difference between the normal wiping range in normal mode and the heavy rain wiping range (narrow wiping range) in heavy rain mode, the evaluation period Mg will not accurately indicate the load state of the drive circuit 7.

[0069] The wiping device A of the first embodiment is a device that wipes rainwater off a wiped surface W by reciprocating a pair of wiper blades 1d, 1p using a motor 4 (power source) and switches the wiping range of the pair of wiper blades 1d, 1p between a normal wiping range and a narrow wiping range narrower than the normal wiping range.It is equipped with a drive circuit 7 that drives the motor 4 (power source) and a control unit 6 that controls the drive circuit 7, and the control unit 6 sets an evaluation period Mg of the load information of the drive circuit 7 in heavy rain mode based on the normal wiping range and the heavy rain wiping range (narrow wiping range).

[0070] According to the first embodiment, the evaluation period Mg of the load information of the drive circuit 7 in heavy rain mode is set based on the normal wiping range and the heavy rain wiping range (narrow wiping range), thereby providing a wiping device A that can appropriately estimate the load state of the drive circuit 7 before and after switching the wiping range.

[0071] Furthermore, according to the first embodiment, when switching between the normal wiping range corresponding to the normal mode and the heavy rain wiping range (narrow wiping range) corresponding to the heavy rain mode, the control unit 6 sets the evaluation period Mg of the heavy rain mode based on the ratio between the normal wiping range and the narrow wiping range as shown in the above equations (1) and (2), so that it is possible to appropriately estimate the load state of the drive circuit 7 before and after switching the wiping range between the normal mode and the heavy rain mode.

[0072] According to the first embodiment, the heavy rain wiping range (narrow wiping range) corresponding to the heavy rain mode is set such that the upper reversal positions of the pair of wiper blades 1d, 1p are the same as the normal wiping range in the normal mode, and the lower reversal positions of the pair of wiper blades 1d, 1p are set to a position higher than the normal wiping range. According to the first embodiment, even with such a method of setting the heavy rain wiping range (narrow wiping range), it is possible to appropriately estimate the load state of the drive circuit 7.

[0073] Furthermore, according to the first embodiment, a single motor 4 is provided as a power source, and the single motor 4 simultaneously reciprocates the pair of wiper blades 1d, 1p. Therefore, according to the first embodiment, in the wiping device A of the single motor drive type, it is possible to appropriately estimate the load state of the drive circuit 7.

[0074] Second Embodiment A second embodiment of the present invention will be described with reference to Fig. 5. A wiping device B according to the second embodiment, like the wiping device A according to the first embodiment, is mounted on various vehicles and wipes rainwater off the surface (wiped surface W) of a windshield or a rear windshield. In Fig. 5, the same components as those in the first embodiment are denoted by the same reference numerals.

[0075] This wiping device B includes a drive control device 10 as shown in Fig. 5. This drive control device 10 includes a pair of motors 4d, 4p and a pair of wiper drive control units 10d, 10p as shown in the figure. In other words, this wiping device B is a dual-motor drive type wiping device. Also, this wiping device B employs an opposed wiping type in which a pair of wiper blades 1d, 1p move opposite each other as shown in Fig. 5. The pair of motors 4d, 4p are the power source in the second embodiment.

[0076] The motor 4d on the driver's seat side includes a motor body 8d and a speed reduction mechanism 9d. The motor 4p on the passenger's seat side includes a motor body 8p and a speed reduction mechanism 9p. A pair of wiper drive controllers 10d and 10p drive and control the pair of motors 4d and 4p, which are power sources.

[0077] Of the pair of wiper drive control units 10d, 10p, the first wiper drive control unit 10d is a drive control unit corresponding to the motor 4d on the driver's seat side, and is equipped with an angle detection circuit 11d, a ROM (Read Only Memory) 12d, a RAM (Random Access Memory) 13d, a communication circuit 14d, a CPU (Central Processing Unit) 15d, and a drive circuit 16d.

[0078] Further, of the pair of wiper drive control units 10d, 10p, the second wiper drive control unit 10p is a drive control unit corresponding to the motor 4p on the passenger side, and is equipped with an angle detection circuit 11p, a ROM (Read Only Memory) 12p, a RAM (Random Access Memory) 13p, a communication circuit 14p, a CPU (Central Processing Unit) 15p, and a drive circuit 16p.

[0079] The driver's seat side motor 4d is driven and controlled by the wiper drive control unit 10d, so that the driver's seat side wiper blade 1d reciprocates (oscillates) around the wiper shaft Td as a fulcrum. The passenger's seat side motor 4p is driven and controlled by the wiper drive control unit 10p, so that the passenger's seat side wiper blade 1b reciprocates (oscillates) around the wiper shaft Tp as a fulcrum.

[0080] In the first wiper drive control unit 10d, the angle detection circuit 11d has a function similar to that of the angle detection circuit 5 in the first embodiment, and outputs an angle signal proportional to the rotation angle of the motor main body 8d to the CPU 15d. This angle signal is a signal indicating the operating angle of the wiper blade 1d on the driver's seat side, and is composed of the relative position signal and absolute position signal described in the first embodiment.

[0081] The ROM 12d is a non-volatile memory. The ROM 12d stores a control program for the CPU 15d to feedback control the wiper blade 1d on the driver's side. The ROM 12d also stores a normal mode operation map and a heavy rain mode operation map required for the CPU 15d to execute the control program. The normal mode operation map and the heavy rain mode operation map indicate the target speed of the wiper blade 1d on the driver's side.

[0082] The RAM 13d is a volatile memory. This RAM 13d temporarily stores various data generated when the CPU 15d executes the control program. For example, the RAM 13d temporarily stores a flag (control flag F) indicating whether the control mode being executed is the normal mode or the heavy rain mode, a counter value (wiping count value N) indicating the number of wiping operations in the control mode being executed, and the like.

[0083] The communication circuit 14d transmits and receives control information to and from the second wiper drive control unit 10p. The communication circuit 14d receives, as the control information, for example, the current position of the wiper blade 1p on the passenger side from the communication circuit 14p of the second wiper drive control unit 10p. The communication circuit 14d also transmits, as the control information, for example, the current position of the wiper blade 1d on the driver side to the communication circuit 14p of the second wiper drive control unit 10p.

[0084] The CPU 15d generates a drive command by executing a control program previously stored in the ROM 12d, and outputs the drive command to the drive circuit 16d. When executing the control program, the CPU 15d refers to the switch signal input from the upper control device, the angle signal input from the angle detection circuit 11d, the control information input from the communication circuit 14d, and the normal mode operation map and the heavy rain mode operation map previously stored in the ROM 12d.

[0085] That is, the CPU 15d generates a drive command by referring to the switch signal, the angle signal, the control information, and the normal mode operation map and the heavy rain mode operation map based on the control program. The drive command is a control command that instructs the drive circuit 16d to drive the wiper blade 1d on the driver's seat side according to the control mode (normal mode or heavy rain mode) and takes into account the drive control state of the wiper blade 1p on the passenger's seat side in the second wiper drive control unit 10p.

[0086] That is, this drive command controls the wiper blade 1d on the driver's side so that the moving speed of the wiper blade 1d on the driver's side obtained from the angle signal becomes equal to the target speed indicated by the normal mode operation map or the heavy rain mode operation map, and is synchronized with the movement of the wiper blade 1p on the passenger's side. Such a CPU 15d on the driver's side is one of the control units in the second embodiment.

[0087] The drive circuit 16d generates a drive signal based on a drive command input from the CPU 15d and outputs the drive signal to the motor 4d. The drive circuit 16d is, for example, an inverter circuit equipped with a plurality of switching transistors. In this case, the drive command is a PWM (Pulse Width Modulation) signal whose duty ratio is variably set according to the deviation between the target speed and the moving speed of the wiper blade 1d on the driver's seat side.

[0088] Here, similar to the CPU 63 of the first embodiment, the CPU 15d executes a load condition estimation process for estimating the load condition of the drive circuit 16d based on a control program in order to protect the drive circuit 16d from an overload of the drive circuit 16d. That is, the CPU 15d acquires information (load information) required for load estimation, such as a drive command and an angle signal, during a predetermined evaluation period preset by the control program, and estimates the load condition of the drive circuit 16d using the load information.

[0089] On the other hand, in the second wiper drive control unit 10p, the angle detection circuit 11p has a function similar to that of the angle detection circuit 5 in the first embodiment, and outputs an angle signal proportional to the rotation angle of the motor main body 8p to the CPU 15p. This angle signal is a signal indicating the operating angle of the passenger side wiper blade 1p, and is composed of the relative position signal and absolute position signal described in the first embodiment.

[0090] The ROM 12p is a non-volatile memory. The ROM 12p stores a control program for the CPU 15p to feedback control the passenger side wiper blade 1p. The ROM 12p also stores a normal mode operation map and a heavy rain mode operation map required for the CPU 15p to execute the control program.

[0091] These normal mode operation map and heavy rain mode operation map indicate the target speed of the wiper blade 1p on the passenger side. The control program stored in the ROM 12p is substantially the same as the control program stored in the ROM 12d of the first wiper drive control unit 10d.

[0092] The RAM 13p is a volatile memory. This RAM 13p temporarily stores various data generated when the CPU 15p executes the control program. For example, this RAM 13p temporarily stores a flag (control flag F) indicating whether the control mode being executed is the normal mode or the heavy rain mode, a counter value (wiping count value N) indicating the number of wiping operations in the control mode being executed, and the like.

[0093] The communication circuit 14p transmits and receives control information to and from the first wiper drive control unit 10d. The communication circuit 14p receives, as the control information, for example, the current position of the wiper blade 1d on the driver's seat side from the communication circuit 14d of the first wiper drive control unit 10d. The communication circuit 14p also transmits, as the control information, for example, the current position of the wiper blade 1p on the passenger's seat side to the communication circuit 14d of the first wiper drive control unit 10d.

[0094] The CPU 15p generates a drive command by executing a control program previously stored in the ROM 12p, and outputs the drive command to the drive circuit 16p. When executing the control program, the CPU 15p refers to the switch signal input from the upper control device, the angle signal input from the angle detection circuit 11p, the control information input from the communication circuit 14p, and the normal mode operation map and the heavy rain mode operation map previously stored in the ROM 12p.

[0095] That is, the CPU 15p generates a drive command by referring to the switch signal, the angle signal, the control information, and the normal mode operation map and the heavy rain mode operation map based on the control program. The drive command is a control command that instructs the drive circuit 16p to drive the passenger side wiper blade 1p according to the control mode (normal mode or heavy rain mode) and takes into account the drive control state of the driver side wiper blade 1d in the first wiper drive control unit 10d.

[0096] That is, this drive command controls the passenger side wiper blade 1d so that the moving speed of the passenger side wiper blade 1p obtained from the angle signal becomes equal to the target speed indicated by the normal mode operation map or the heavy rain mode operation map, and is synchronized with the movement of the driver side wiper blade 1p. Such a passenger side CPU 15p is the other control unit in the second embodiment.

[0097] The drive circuit 16p generates a drive signal based on a drive command input from the CPU 15p and outputs the drive signal to the motor 4p. The drive circuit 16p is, for example, an inverter circuit equipped with a plurality of switching transistors. In this case, the drive command is a PWM (Pulse Width Modulation) signal whose duty ratio is variably set according to the deviation between the target speed and the moving speed of the wiper blade 1p on the passenger side.

[0098] Here, the CPU 15p executes a load state estimation process for estimating the load state of the drive circuit 16p based on a control program in order to protect the drive circuit 16p from an overload of the drive circuit 16p. That is, the CPU 15p acquires information (load information) required for load estimation, such as a drive command and an angle signal, during a predetermined evaluation period preset by the control program, and estimates the load state of the drive circuit 16p using the load information.

[0099] Next, the operation of the wiping device B according to the second embodiment will be described. In this wiping device B, a first wiper drive control unit 10d controls the rotation of a motor 4d on the driver's seat side based on a control program, so that a wiper blade 1d on the driver's seat side performs a wiping operation on a surface to be wiped W. Also, in this wiping device B, a second wiper drive control unit 10p controls the rotation of a motor 4p on the passenger's seat side based on a control program, so that a wiper blade 1p on the passenger's seat side performs a wiping operation on a surface to be wiped W.

[0100] Furthermore, in the wiping device B, control information of the first wiper drive control unit 10d and control information of the second wiper drive control unit 10p are exchanged with each other through a pair of communication circuits 14d and 14p, so that the wiper blade 1d on the driver's seat side and the wiper blade 1p on the passenger's seat side perform wiping operations in synchronization with each other.

[0101] The control of the wiper blade 1d on the driver's side by the first wiper drive control unit 10d and the control of the wiper blade 1p on the passenger's side by the second wiper drive control unit 10p are generally the same. In addition, the switching process between the normal mode and the heavy rain mode in the wiping device B is the same as the switching process in the first embodiment.

[0102] That is, the pair of CPUs 15d, 15p in the pair of wiper drive control units 10d, 10p recognize the operation mode instructed by the upper control device (ECU) by referring to a switch signal input from the upper control device. Then, the pair of CPUs 15d, 15p switch between the normal mode and the heavy rain mode based on the recognition result.

[0103] For example, when a normal mode is instructed from a higher-level control device, the CPUs 15d and 15p read out a normal mode operation map from the ROMs 12d and 12p based on a control program. Then, the CPUs 15d and 15p generate drive commands based on the normal mode operation map and angle signals input from the angle detection circuits 11d and 11p, and output the drive commands to the drive circuits 16d and 16p.

[0104] The drive circuits 16d, 16p generate drive signals based on the drive commands and supply them to the motors 4d, 4p to reciprocate the pair of wiper blades 1d, 1p. That is, in the normal mode of the wiping device B, the pair of wiper blades 1d, 1p are feedback-controlled by the CPUs 15d, 15p based on the normal mode operation map and the angle signal.

[0105] On the other hand, when the heavy rain mode is instructed from the upper control device, the CPUs 15d, 15p read out the heavy rain mode operation map from the ROMs 12d, 12p based on the control program. Then, the CPUs 15d, 15p generate drive commands based on the heavy rain mode operation map and the angle signals input from the angle detection circuits 11d, 11p, and output the drive commands to the drive circuits 16d, 16p.

[0106] The drive circuits 16d, 16p generate drive signals based on the drive commands and supply them to the motors 4d, 4p to reciprocate the pair of wiper blades 1d, 1p. That is, in the normal mode of the wiping device B, the pair of wiper blades 1d, 1p are feedback-controlled by the CPUs 15d, 15p based on the heavy rain mode operation map and the angle signal.

[0107] In parallel with the feedback control (normal processing) of the pair of wiper blades 1d, 1p in the normal mode or the heavy rain mode, the CPUs 15d, 15p execute a load condition estimation process similar to that shown in Fig. 2 of the first embodiment. The CPUs 15d, 15p recognize the load conditions of the drive circuits 16d, 16p through the load condition estimation process.

[0108] That is, the CPU 15d, 15p judges whether the normal process currently being executed is the normal process for the heavy rain mode (step S1). If the judgment in step S1 is "No", the CPU 15d, 15p executes the normal load estimation calculation (calculation C1) (step S2).

[0109] On the other hand, when the determination in step S1 is "Yes", the CPUs 15d and 15p execute a load estimation calculation (calculation C2) including detection range correction (step S3). Note that calculations C1 and C2 in the second embodiment are similar to calculations C1 and C2 in the first embodiment, and therefore will not be described again here.

[0110] The wiping device B of the second embodiment wipes rainwater off a surface to be wiped W by reciprocating a pair of wiper blades 1d, 1p using a pair of motors 4d, 4p (power sources) and switches the wiping range of the pair of wiper blades 1d, 1p between a normal wiping range and a narrow wiping range narrower than the normal wiping range.The wiping device B is equipped with a pair of drive circuits 16d, 16p that drive the pair of motors 4d, 4p (power sources) and a pair of CPUs 15d, 15p (control units) that respectively control the pair of drive circuits 16d, 16p. The pair of CPUs 15d, 15p (control units) set an evaluation period Mg of load information of the drive circuit 7 in heavy rain mode based on the normal wiping range and the heavy rain wiping range (narrow wiping range).

[0111] According to the second embodiment, the evaluation period Mg of the load information of the pair of drive circuits 16d, 16p in heavy rain mode is set based on the normal wiping range and the heavy rain wiping range (narrow wiping range), thereby providing a wiping device B that can appropriately estimate the load state of the pair of drive circuits 16d, 16p before and after switching the wiping range.

[0112] Furthermore, in the wiping device B according to the second embodiment, the pair of CPUs 15d, 15p (controllers) set the evaluation period Mg of the heavy rain mode based on the ratio of the normal wiping range to the narrow wiping range as shown in the above formulas (1) and (2) when switching between the normal wiping range corresponding to the normal mode and the heavy rain wiping range (narrow wiping range) corresponding to the heavy rain mode. Therefore, according to the second embodiment, it is possible to appropriately estimate the load state of the pair of drive circuits 16d, 16p before and after switching the wiping range between the normal mode and the heavy rain mode.

[0113] According to the second embodiment, the heavy rain wiping range (narrow wiping range) corresponding to the heavy rain mode is set such that the upper reversal positions of the pair of wiper blades 1d, 1p are the same as the normal wiping range in the normal mode, and the lower reversal positions of the pair of wiper blades 1d, 1p are set to a position higher than the normal wiping range. According to the second embodiment, the method of setting the heavy rain wiping range (narrow wiping range) also makes it possible to appropriately estimate the load state of the pair of drive circuits 16d, 16p.

[0114] Furthermore, in the second embodiment, a pair of motors 4d, 4p are provided as power sources, and of the pair of wiper blades 1d, 1p, the motor 4d on the driver's seat side reciprocates the wiper blade 1d on the driver's seat side, and the motor 4p on the passenger's seat side reciprocates the wiper blade 1p on the passenger's seat side.

[0115] In this second embodiment, in a dual-motor drive wiping device B in which a pair of motors 4d, 4p (power sources) reciprocate the wiper blades corresponding to the motors, it is possible to appropriately estimate the load state of a pair of drive circuits 16d, 16p. [Explanation of symbols]

[0116] A, B... wiping device, W... wiped surface, PUa, PUb... upper inversion position, PLa, PLb... lower inversion position, Ra, Rb... wiping range, Ta, Tb... fulcrum, 1d, 1p... wiper blade, 2d, 2p... wiper arm, 3... link mechanism, 4, 4d, 4p... motor (power source), 5... angle detection circuit, 6... control unit, 61... ROM, 62... RAM, 63... CPU, 7... drive circuit, 8d, 8p... motor body, 9d, 9p... reduction mechanism, 10... drive control device, 10d, 10p... wiper drive control unit, 11d, 11p... angle detection circuit, 12d, 12p... ROM, 13d, 13p... RAM, 14d, 14p... communication circuit, 15d, 15p... CPU (control unit), 16d, 16p... drive circuit

Claims

1. A wiping device that wipes rainwater off a surface to be wiped by reciprocating a wiper blade using a predetermined power source and switches a wiping range of the wiper blade between a normal wiping range and a narrow wiping range that is narrower than the normal wiping range, A drive circuit that drives the power source; A control unit that controls the drive circuit, The wiping device according to claim 1, wherein the control unit sets an evaluation period for load information of the drive circuit based on the normal wiping range and the narrow wiping range.

2. The wiping device according to claim 1, characterized in that, when switching between the normal wiping range corresponding to the normal mode and the narrow wiping range corresponding to the heavy rain mode, the control unit sets the evaluation period of the heavy rain mode based on the ratio between the normal wiping range and the narrow wiping range.

3. 3. The wiping device according to claim 2, wherein the narrow wiping range is a range in which an upper reversal position of the wiper blade is the same as that of the normal wiping range, and a lower reversal position of the wiper blade is higher than that of the normal wiping range.

4. 3. The wiping device according to claim 1, wherein the power source reciprocates the pair of wiper blades simultaneously.

5. 3. The wiping device according to claim 1, wherein the power source is provided in a pair, and reciprocates the wiper blade corresponding to the power source.

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