Vehicle wiper device and control method of vehicle wiper device

Abstract

A wiper device for a vehicle includes a wiper motor, a control unit that drives the wiper motor to reciprocate rotation and controls a rotation speed of the wiper motor, and a wiper that reciprocates rotation by being transmitted the reciprocating rotation of the wiper motor, reciprocally wipes a wiped surface of the vehicle with a squeegee rubber, and switches a dumping direction of a lip portion of the squeegee rubber at a time of reversal of a rotation direction. The control unit accelerates the rotation speed of the wiper motor from zero to a first speed (V1) that is a low speed at a first average acceleration (AC1) in a first acceleration section (AS1) in which the dumping direction of the lip portion is switched, and accelerates the rotation speed to a speed that is higher than the first speed (V1) and is a half of a second speed (V2) at an average acceleration that is twice or more the first average acceleration (AC1) in a first half of a second acceleration section (AS2) that follows the first acceleration section (AS1).

Description

[0001] Citation of relevant applications

[0002] This application is based on Japanese Patent Application No. 2021-082264, filed on May 14, 2021, the contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure relates to a windshield wiper device for vehicles and a control method thereof. Background Technology

[0004] In the windshield wiper control device described in Japanese Patent Application Publication No. 2005-231590, a crank arm connected to the output shaft of the wiper motor and a wiper blade supported on a pivot are connected by a linkage mechanism. This linkage mechanism converts the unidirectional rotational motion of the wiper motor into the reciprocating rotational motion of the wiper blade. As a result, the wiper blade rubber reciprocates on the windshield while tilting its lip, wiping the surface of the windshield. During this wiping, a detection mechanism detects the rotation angle of the crank arm, and a drive control mechanism controls the drive of the wiper motor based on this detection result.

[0005] When the wiper's movement direction reverses, the aforementioned drive control mechanism decelerates at the midpoint between the start and end positions of the wiper blade rubber's reversal, minimizing the wiper motor's rotational speed, and then accelerates after passing this midpoint. At this time, by driving the wiper motor at a set minimum speed without stopping it, the perceived longer stop time during wiper reversal is suppressed. Furthermore, by sufficiently decelerating the wiper during reversal and preventing a sharp increase in wiper speed after reversal, the reversing noise caused by the change in the wiper blade rubber's tilting direction is suppressed. Summary of the Invention

[0006] The technical problem that the invention aims to solve

[0007] As with the prior art described above, simply reducing the rotational speed of the wiper motor near the reverse position of the wiper results in a decrease in the wiper's rotational speed during reverse rotation, increasing the coefficient of friction between the wiper blade rubber and the windshield, thus inducing vibration of the wiper blade rubber. Therefore, it is difficult to drastically reduce the rotational speed of the wiper motor starting from the reverse position of the wiper. Consequently, the switching speed of the wiper blade lip's tilt direction cannot be sufficiently reduced, limiting the noise reduction effect during reverse rotation. Furthermore, in the prior art described above, the linkage mechanism that converts the unidirectional rotational motion of the wiper motor into the reciprocating rotational motion of the wiper requires a large installation space, particularly space sufficient to allow for 360° rotation of the crank arm. Therefore, there is room for improvement from the perspective of enhancing vehicle installation comfort.

[0008] This disclosure is made in view of the above-mentioned problems, and its purpose is to provide a vehicle wiper device and its control method that can reduce the reverse noise of the wiper blade and suppress vibration, and improve the vehicle's installability.

[0009] Technical solutions adopted to solve technical problems

[0010] To achieve the above objectives, the vehicle wiper device disclosed herein includes: a wiper motor (18, 20); a control unit (60, 62) that drives the wiper motor to reciprocate and controls the rotational speed of the wiper motor; and a wiper (14, 16) that reciprocates by being driven by the reciprocating rotation of the wiper motor, and uses a wiper blade rubber (31) to reciprocate the surface (12A) of the vehicle to be wiped, and when the rotation direction is reversed, the wiper blade rubber (31) is used to wipe the lip (31) of the wiper blade rubber. A) The control unit switches the tilting direction. In the first acceleration interval (AS1) of switching the tilting direction of the lip, the control unit accelerates the rotational speed of the wiper motor from zero to a low speed (V1) with a first average acceleration (AC1). In the first half of the second acceleration interval (AS2) following the first acceleration interval, the control unit rapidly accelerates the rotational speed to a speed that is higher than the first speed and half the speed of the second speed (V2) with an average acceleration that is more than twice the first average acceleration.

[0011] Furthermore, in order to achieve the above-mentioned objective, in the control method of the vehicle wiper device disclosed herein, the wiper is rotated back and forth by transmitting the reciprocating rotation of the wiper motor, and the wiper blade rubber of the wiper is used to reciprocate to wipe the surface of the vehicle. When the rotation direction of the wiper is reversed, the tilting direction of the lip of the wiper blade rubber is switched. In the first acceleration interval where the tilting direction of the lip is switched, the rotation speed of the wiper motor is accelerated from zero to a low first speed with a first average acceleration. In the first half of the second acceleration interval following the first acceleration interval, the rotation speed is rapidly accelerated to a speed that is higher than the first speed and half the second speed with an average acceleration of more than twice the first average acceleration.

[0012] In this disclosure, during the first acceleration interval where the tilting direction of the wiper blade rubber lip is switched, the rotational speed of the wiper motor accelerates from zero to a low speed with a first average acceleration. By setting this first speed to a low speed, the reverse noise caused by the aforementioned switching can be reduced. Furthermore, in the second acceleration interval following the first acceleration interval, the rotational speed of the wiper motor accelerates to a speed higher than the first speed and half the second speed with an average acceleration of more than twice the first average acceleration. By accelerating to half the second speed, the coefficient of friction of the wiper blade rubber relative to the wiped surface is lower, thus suppressing wiper blade rubber vibration. Moreover, since the structure drives the wiper motor to reciprocate, compared to a structure that converts the unidirectional rotational motion of the wiper motor into the reciprocating rotational motion of the wiper, the linkage mechanism can be eliminated or the operating space can be miniaturized, thereby correspondingly improving the vehicle's installability. Attached Figure Description

[0013] The above-mentioned objects, other objects, features, and advantages of this disclosure will become clearer with reference to the accompanying drawings and the following detailed description. The drawings are described below.

[0014] Figure 1 This is a schematic diagram showing the structure of the vehicle windshield wiper device according to the first embodiment.

[0015] Figure 2 This is a cross-sectional view showing the structure of the scraper rubber.

[0016] Figure 3 It is a cross-sectional view of the scraper rubber moving in one direction of reciprocating rotation.

[0017] Figure 4 It is a cross-sectional view of the scraper rubber moving to the opposite side of the reciprocating rotation direction.

[0018] Figure 5This is a block diagram showing the structure of the vehicle windshield wiper device according to the first embodiment.

[0019] Figure 6 It is a graph showing the relationship between the rotational speed of the windshield wiper motor and time.

[0020] Figure 7 It is relative to Figure 6 To represent by changing the proportion Figure 6 A portion of the graph.

[0021] Figure 8 It is a graph showing the relationship between the rotational speed of the wiper motor and the angle of the output shaft.

[0022] Figure 9 It is relative to Figure 7 To represent by changing the proportion Figure 7 A portion of the graph.

[0023] Figure 10 It is relative to Figure 8 To represent by changing the proportion Figure 8 A portion of the graph.

[0024] Figure 11 It is a cross-sectional view used to illustrate the first acceleration zone and the second acceleration zone.

[0025] Figure 12 It is a graph showing the relationship between the rotational speed of the windshield wiper motor and time.

[0026] Figure 13 It is a graph showing the relationship between the rotational speed of the pivot and time.

[0027] Figure 14 It is a graph showing the relationship between the sliding speed (moving speed) of the scraper rubber relative to the surface being wiped and time.

[0028] Figure 15A This is a cross-sectional view of the scraper rubber before it reaches the reverse position on one side.

[0029] Figure 15B This is a cross-sectional view of the scraper rubber after it has reached the reversed position on one side.

[0030] Figure 15C It is a cross-sectional view of the scraper rubber in the middle of the reversal at the reversal position of one side.

[0031] Figure 15D This is a cross-sectional view of the scraper rubber at the point where the reversal has just ended at the reversal position on one side.

[0032] Figure 15E This is a cross-sectional view showing the scraper rubber leaving from one of the reversed positions.

[0033] Figure 16 It is a graph showing the relationship between the rotational speed of the wiper motor and time, and it is also a graph showing an example of changing the rotational speed of the wiper motor based on the detection results of the rain sensor and the vehicle speed sensor.

[0034] Figure 17 This is a bar chart comparing the noise levels of the first embodiment and conventional methods.

[0035] Figure 18 This is a schematic diagram showing the structure of the vehicle windshield wiper device according to the second embodiment.

[0036] Figure 19 This is a block diagram showing a partial structure of the vehicle windshield wiper device according to the third embodiment.

[0037] Figure 20 This represents the relationship between the rotational speed of the wiper motor and time in the vehicle wiper device of the fourth embodiment. Figure 7 The corresponding curve graph.

[0038] Figure 21 This describes the relationship between the rotational speed of the wiper motor and the angle of the output shaft in the vehicle wiper device of the fourth embodiment. Figure 8 The corresponding curve graph. Detailed Implementation

[0039] <First Implementation>

[0040] Below, refer to Figures 1 to 17 The first embodiment of the vehicle windshield wiper device 10 and its control method thereof will be described. The vehicle windshield wiper device 10 of this embodiment is a device for wiping a wiped surface 12A provided on the outer surface of the windshield 12 of a vehicle such as an automobile. The vehicle windshield wiper device 10 includes a pair of wipers 14 and 16, a wiper motor 18, a linkage mechanism 22, and a wiper control circuit 60 as a control unit. The aforementioned control method is implemented by the wiper control circuit 60.

[0041] As an example, windshield wipers 14 and 16 are cascaded and rotate in the same direction, each having wiper arms 24 and 26 and wiper blades 28 and 30. The wiper arms 24 and 26 and the wiper blades 28 and 30 are all elongated. One end (base end) of the long side of the wiper arms 24 and 26 is fixed to pivots 42 and 44. Pivots 42 and 44 are supported for rotation by pivot retainers (not shown) provided on the vehicle body, allowing the wiper arms 24 and 26 to reciprocate about the pivots 42 and 44.

[0042] Wiper blades 28 and 30 each include a wiper rubber 31 made of rubber or the like (see reference). Figure 2 The wiper blade rubber 31 and its retaining member (not shown) are also present. Each wiper blade rubber 31 and each retaining member is formed as a strip, with the middle portion of the long side of each retaining member connected to the other end (front end) of the long side of the wiper arms 24 and 26. The front ends of the wiper arms 24 and 26 are subjected to force towards the wiped surface 12A by a force-applying mechanism (not shown), such as... Figure 3 and Figure 4 As shown, the wiper blade rubber 31 of wiper blades 28 and 30 is pressed against the surface 12A being wiped. Additionally, in Figure 3 and Figure 4 In the diagram, arrow R indicates the rotation direction (movement direction) of the scraper rubber 31.

[0043] By rotating the wiper blades 28 and 30 and wiper arms 24 and 26 together around pivots 42 and 44, the wiped surface 12A is repeatedly wiped by the rubber of each wiper blade 31. Figures 2-4 As shown, the scraper rubber 31 integrally has a lip (wiping portion) 31A with an approximately inverted triangular cross section, a holding portion 31B, and a thin-walled neck 31C. The lip 31A contacts the wiping surface 12A and performs wiping. The holding portion 31B is held in the holding member. The neck 31C connects the lip 31A and the holding portion 31B.

[0044] On the retaining portion 31B of the scraper rubber 31, along its long side direction (in Figures 2-4 A pair of retaining grooves (symbols omitted) are formed in the direction perpendicular to the paper surface, and a backing 33, for example, formed of a spring material in the shape of a long flat plate, is embedded in each retaining groove. The scraper rubber 31 rotates while causing the front end of the lip 31A to slide into contact with the surface being wiped 12A. Figure 3 and Figure 4 As shown, the scraper rubber 31 is configured to switch the tilting direction of the lip 31A according to its rotation direction (movement direction).

[0045] The wiper motor 18 has a reduction mechanism 52, for example, including a worm gear, which enables the output shaft 32 provided in the reduction mechanism 52 to rotate in both directions. The linkage mechanism 22 includes a crank arm 34, a first connecting rod 36, a pair of pivots 38 and 40, the aforementioned pair of pivots 42 and 44, and a second connecting rod 46.

[0046] One end of the crank arm 34 is fixed to the output shaft 32. The other end of the crank arm 34 is rotatably connected to one end of the first connecting rod 36. The other end of the first connecting rod 36 is connected to the middle part of the pivot rod 38. The two ends of the second connecting rod 46 are rotatably connected to one end of the pivot rods 38 and 40, respectively. The other ends of the pivot rods 38 and 40 are fixed to the pivots 42 and 44, respectively.

[0047] When the output shaft 32 of the wiper motor 18 reciprocates (rotates in both directions) within a specified range of rotation angle θ1, the rotational force of the output shaft 32 is transmitted to the wiper arms 24 and 26 via the linkage mechanism 22, causing the wiper arms 24 and 26 to reciprocate. Consequently, the wiper blades 28 and 30, connected to the front ends of the wiper arms 24 and 26, reciprocate between a downward reversing position P2 and an upward reversing position P1 set on the windshield 12. The value of the aforementioned rotation angle θ1 can take various values ​​depending on the structure of the linkage mechanism 22, but in this embodiment, it is set to 140° as an example.

[0048] In addition, in this embodiment, such as Figure 1 As shown, with the wiper blades 28 and 30 positioned in the retracted position P3, which is lower than the reverse position P2, the crank arm 34 and the first connecting rod 36 are arranged in a straight line. Starting from the reverse position P2, the output shaft 32 is rotated by a rotation angle θ2, causing the wiper blades 28 and 30 to rotate towards the retracted position P3. The value of the rotation angle θ2 can take various values ​​depending on the structure of the connecting rod mechanism 22, but in this embodiment, it is set to 10° as an example. Furthermore, when the rotation angle θ2 is zero, the reverse position P2 is configured to coincide with the retracted position P3, and the wiper blades 28 and 30 stop and are retracted at the reverse position P2.

[0049] A wiper control circuit 60 is connected to the wiper motor 18 to drive the wiper motor 18 to reciprocate and control the rotational speed of the wiper motor 18. The wiper control circuit 60, for example, is located within the reduction gear 52 of the wiper motor 18 and includes a drive circuit 60A and a wiper ECU 60B. A rotation angle sensor 42 is connected to the wiper ECU 60B to detect the rotational speed and rotation angle of the output shaft 32 of the wiper motor 18. The rotation angle sensor 42, for example, is located within the reduction gear 52 of the wiper motor 18 and converts the magnetic field (magnetic force) of the excitation coil or magnet rotating in conjunction with the output shaft 32 into an electric current and detects it.

[0050] Because the wiper motor 18 has a reduction gear 52, the rotational speed and rotational angle of the output shaft 32 are different from the rotational speed and rotational angle of the motor body of the wiper motor 18. However, in this embodiment, since the motor body of the wiper motor 18 and the reduction gear 52 are integrally formed and cannot be separated, the rotational speed and rotational angle of the output shaft 32 will be regarded as the rotational speed and rotational angle of the wiper motor 18 below.

[0051] The wiper ECU 60B calculates the position of the wiper blades 28 and 30 on the windshield 12 based on signals from the rotation angle sensor 42. Furthermore, the wiper ECU 60B controls the drive circuit 60A to change the rotational speed of the output shaft 32 according to the calculated position.

[0052] The drive circuit 60A generates and supplies power to the wiper motor 18 via PWM (Pulse Width Modulation) control. The drive circuit 60A includes, for example, a circuit using a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) as a switching element, and outputs a voltage with a predetermined duty cycle under the control of the wiper ECU 60B.

[0053] A wiper switch 66 is connected to the wiper ECU 60B via the vehicle control circuit 64. The wiper ECU 60B reads the rotation signal of the output shaft 32 and controls the voltage applied to the wiper motor 18 to make the wiper blades 28, 30 rotate in a desired reciprocating wiping cycle based on the command signal from the wiper switch 66.

[0054] The wiper switch 66 is a switch used to turn on or off the power supplied from the vehicle's battery to the wiper motor 18. For example, the wiper switch 66 can be switched to the following positions: a low-speed operating mode selection position (LO) for the wipers 14 and 16 to rotate at a low speed; a high-speed operating mode selection position (HI) for the wipers 14 and 16 to rotate at a high speed; an intermittent operating mode selection position (INT) for the wipers 14 and 16 to rotate intermittently at a certain cycle; an automatic mode selection position (Auto) for automatically changing the wiping action or wiping speed of the wipers 14 and 16 according to the vehicle's driving conditions or driving environment; and a stop mode selection position (Off) for stopping the rotation of the wipers 14 and 16.

[0055] Depending on the selected position of each of the aforementioned modes, the wiper switch 66 outputs a command signal to the wiper ECU 60B via the vehicle control circuit 64 to cause the wiper motor 18 to rotate reciprocally. For example, when the wiper switch 66 is in the high-speed operating mode selection position, the wiper motor 18 rotates at high speed; when the wiper switch 66 is in the low-speed operating mode selection position, the wiper motor 18 rotates at low speed; and when the wiper switch 66 is in the intermittent operating mode selection position, the wiper motor 18 rotates intermittently.

[0056] When the signal output from the wiper switch 66 according to the selected position of each mode is input to the wiper ECU 60B, the wiper ECU 60B performs control corresponding to the output signal from the wiper switch 66. Specifically, the wiper ECU 60B calculates the rotational speed of the output shaft 32 based on the command signal from the wiper switch 66. Furthermore, the wiper ECU 60B controls the drive circuit 60A to make the output shaft 32 rotate at the calculated rotational speed.

[0057] Additionally, a rain sensor 67 and a vehicle speed sensor 68 are connected to the wiper ECU 60B via the vehicle control circuit 64. The rain sensor 67 detects rainfall as the vehicle's driving environment. The vehicle speed sensor 68 detects the vehicle's speed as the vehicle's driving status. For example, when the wiper switch 66 is in the automatic mode selection position, the wiper ECU 60B controls the rotation speed of the output shaft 32 based on the detection results of the rain sensor 67 and the vehicle speed sensor 68.

[0058] Figure 5 This is a block diagram illustrating a schematic example of the structure of the windshield wiper control circuit 60. Figure 5 The wiper motor 18 shown is, as an example, a brushed DC motor. Figure 5 The wiper control circuit 60 shown includes: a drive circuit 60A that generates a voltage applied to the terminals of the windings of the wiper motor 18; and a microcomputer 48 of the wiper ECU 60B, which controls the switching of the switching elements constituting the drive circuit 60A. In the microcomputer 48, power from the battery 80 is supplied via a diode 56, and the voltage of the supplied power is detected by a voltage detection circuit 50 disposed between the diode 56 and the microcomputer 48, and the detection result is output to the microcomputer 48. Additionally, an electrolytic capacitor C1 is provided, with one end connected between the diode 56 and the microcomputer 48 and the other end grounded. The electrolytic capacitor C1 is used to stabilize the power supply to the microcomputer 48. For example, the electrolytic capacitor C1 stores sudden high voltages such as power surges and protects the microcomputer 48 by discharging to the ground.

[0059] Command signals used to indicate the rotational speed of the wiper motor 18 are input to the microcomputer 48 from the wiper switch 66 and the vehicle control circuit 64 via the signal input circuit 52. When the command signal output from the wiper switch 66 is an analog signal, the signal is digitized in the signal input circuit 52 and input to the microcomputer 48.

[0060] Additionally, a rotation angle sensor 42 is connected to the microcomputer 48 to detect the magnetic field of the sensor magnet 70, which changes according to the rotation of the output shaft 32. Based on the signal output by the rotation angle sensor 42, the microcomputer 48 calculates the rotation angle of the output shaft 32, thereby determining the position of the wiper blades 28 and 30 on the windshield 12.

[0061] Furthermore, the microcomputer 48 refers to the data stored in the memory 54 on the rotational speed of the wiper motor 18 determined according to the position of the wiper blades 28 and 30, and controls the drive circuit 60A so that the rotation of the wiper motor 18 reaches the speed corresponding to the determined position of the wiper blades 28 and 30.

[0062] like Figure 5 As shown, the drive circuit 60A uses N-type FETs (field-effect transistors), namely transistors Tr1, Tr2, Tr3, and Tr4, as switching elements. The drains of transistors Tr1 and Tr2 are connected to the battery 80 via noise reduction coils 76, respectively, and their sources are connected to the drains of transistors Tr3 and Tr4, respectively. Furthermore, the sources of transistors Tr3 and Tr4 are grounded.

[0063] In addition, the source of transistor Tr1 and the drain of transistor Tr3 are connected to one end of the winding of the wiper motor 18, and the source of transistor Tr2 and the drain of transistor Tr4 are connected to the other end of the winding of the wiper motor 18.

[0064] By inputting high-level signals to the gates of transistors Tr1 and Tr4 respectively, transistors Tr1 and Tr4 are turned on, thereby allowing a CW current 72 to flow in the wiper motor 18, which, for example, causes the wiper blades 28 and 30 to move in a clockwise direction when viewed from the passenger side. Furthermore, when one of the control transistors Tr1 and Tr4 is turned on, the other is subjected to PWM control. By performing on / off control in small increments, the voltage of the CW current 72 can be modulated.

[0065] Furthermore, by inputting a high-level signal to the gates of transistors Tr2 and Tr3 respectively, transistors Tr2 and Tr3 are turned on, thereby allowing a CCW current 74 to flow in the wiper motor 18, which, for example, causes the wiper blades 28 and 30 to move counterclockwise when viewed from the passenger side. In addition, when one of the control transistors Tr2 and Tr3 is turned on, the other is controlled by PWM, and the voltage of the CCW current 74 can be modulated by performing on / off control in small increments.

[0066] In this embodiment, a reverse connection protection circuit 58 and a noise reduction coil 76 are provided between the battery 80, which serves as the power source, and the drive circuit 60A, and an electrolytic capacitor C2 is provided in parallel with the drive circuit 60A. The noise reduction coil 76 is a component used to suppress noise generated by the switching of the drive circuit 60A.

[0067] Electrolytic capacitor C2 is a component used to mitigate noise generated by drive circuit 60A and to store sudden high voltages such as power surges and discharge them to the ground area, thereby preventing excessive current from being input into drive circuit 60A.

[0068] Reverse connection protection circuit 58 is used to connect the positive and negative terminals of battery 80 to... Figure 5 In the case of reverse connection as shown, a circuit protects the components constituting the wiper control circuit 60. As an example, the reverse connection protection circuit 58 is composed of a FET, which is a diode-connected circuit, with its drain and gate connected.

[0069] Next, refer to Figures 6-17 The rotational speed control of the wiper motor 18 by the wiper control circuit 60 will be explained. Figure 6 It is a graph showing the relationship between the speed of the motor, which is the rotational speed of the wiper motor, and time. Figure 7 It is relative to Figure 6 To represent by changing the proportion Figure 6 A portion of the graph. Figure 8 It is a graph showing the relationship between the speed of the motor and the angle of the output shaft 32. Figure 9 It is relative to Figure 7 To represent by changing the proportion Figure 7 A portion of the graph. Figure 10 It is relative to Figure 8 To represent by changing the proportion Figure 8 A portion of the graph. In Figures 6-10 In the diagram, the solid line represents an example of the rotational speed control of the wiper motor 18 in this embodiment. Figures 6-10 In the diagram, the double-dotted line represents an example of windshield wiper motor speed control in a conventional vehicle windshield wiper system that causes the wiper motor to reciprocate (hereinafter referred to as the "first comparative example"). Additionally, in Figure 7 and Figure 10 In the diagram, the single-dotted line represents an example of windshield wiper motor rotation speed control in a vehicle windshield wiper system that reciprocates the motor, where the motor speed is simply reduced near the reverse position of the wiper (hereinafter referred to as the "Second Comparative Example"). Figure 9 and Figure 10In the diagram, the points Va1, Va2, Vb1, Vb2, Vc1, and Vc3 correspond to each other.

[0070] In this embodiment, such as Figure 6 and Figure 7 As shown in the graph with the solid line, the wiper control circuit 60 is configured to control the rotational speed of the wiper motor 18, which consists of a first acceleration range AS1, a second acceleration range AS2, and a deceleration range DS. Through this rotational speed control, the angle of the output shaft 32 of the wiper motor 18 is as follows: Figure 8 The change is as shown by the solid line. In addition, at the upper reverse position P1 and the lower reverse position P2, since only the reverse direction of the wipers 14 and 16 is different but the basic operation is the same, the upper reverse position P1 and the lower reverse position P2 will be referred to as "reverse position P" in the following description.

[0071] like Figure 11 As shown, the first acceleration interval AS1 is the interval in which the tilting direction of the lip 31A of the wiper rubber 31 is switched when the wipers 14 and 16 reverse at the reverse position P, and it is also the interval in which the wiper motor 18 rotates at a very low speed. In this embodiment, in the first acceleration interval AS1, the tilting direction of the lip 31A is switched at the middle of the long side of the wiper rubber 31. Specifically, in this embodiment, the wiper rubber 31 of the wiper 30 is formed to be longer than the wiper rubber 31 of the wiper 28. Moreover, in the aforementioned first acceleration interval AS1, the tilting direction of the lip 31A is switched at the middle of the long side of the longest wiper rubber 31 among the plurality of wiper rubbers 31 (i.e., the wiper rubber 31 of the wiper 30). The second acceleration interval AS2 is the next interval after the first acceleration interval AS1, and it is the interval in which the rotational speed of the wiper motor 18 is accelerated to the highest speed corresponding to the selected position of the wiper switch 66. The deceleration range DS is the next range after the second acceleration range AS2, and it is the range in which the rotational speed of the wiper motor 18 is reduced from the aforementioned maximum speed to zero. For example... Figure 8 As shown, the first acceleration interval AS1 coincides with the reverse rotation interval IS of the scraper rubber 31, and the second acceleration interval AS2 and deceleration interval DS constitute the wiping interval WS of the surface 12A being wiped by the scraper rubber 31. During the reverse rotation interval IS of the scraper rubber 31, wiping of the surface 12A by the scraper rubber 31 is not performed.

[0072] The aforementioned first acceleration interval AS1 is the interval from when the wiper rubber 31 reaches one of the reversing positions P and begins to reverse until the end of the switching of the tilting direction of the lip 31A. This first acceleration interval AS1 can also be set to the interval where the switching of the tilting direction of the lip 31A ends in the entire area along the long side of the wiper rubber 31 (the entire area from the front end to the rear end). In this first acceleration interval AS1, the wiper control circuit 60 accelerates the motor speed from zero to a low speed V1 with a first average acceleration AC1. Specifically, in this first acceleration interval AS1, as... Figure 6 and Figure 7 As shown, the wiper control circuit 60, after rapidly accelerating the motor speed from zero (which temporarily becomes zero due to the reversal of rotation) to a low first speed V1, suppresses the acceleration of the motor speed. Specifically, after rapidly accelerating the motor speed from zero to an extremely low first speed V1 (the first rapid acceleration portion), the wiper control circuit 60 sets the motor speed to a constant or approximately constant speed (the first constant speed portion). That is, as the tilting direction of the lip 31A changes, the wiper rubber 31 also displaces in the vertical direction relative to the wiped surface 12A, but in order to minimize the kinetic energy generated by this displacement, the motor speed in the first acceleration range AS1 is set to an extremely low first speed V1 or an equivalent speed. However, in order to suppress the longer stopping time when the reverse rotation of the wipers 14 and 16 is felt, the motor speed is rapidly accelerated to the first speed V1. Therefore, Figures 6-10 The curve representing the solid line in this embodiment is formed in the first acceleration interval AS1 in a stepped or similar shape, and is formed with an upwardly convex curved portion BP1 (in Figure 6 The shape of the symbol (excluding the symbol).

[0073] In the aforementioned first acceleration zone AS1, since the tilting direction of the lip 31A of the scraper rubber 31 switches at an extremely low speed, the reversal sound caused by this switching can be effectively reduced. Furthermore, as... Figure 7 and Figure 9 As shown, with the horizontal axis representing the time axis, even in the second comparative example where the motor speed at the reverse position is simply reduced, a reduction in the reverse noise can be observed. However, as... Figure 8 and Figure 10 As shown, if the horizontal axis is converted to the angle axis of the output shaft 32, in the second comparative example, it can be seen that because the motor speed in the reverse operation interval IS is not sufficiently reduced, the reduction effect of the reverse tone is small. By rapidly accelerating the motor speed at the beginning of the first acceleration interval AS1 as in this embodiment, it is possible to... Figure 10 The motor speeds at the midpoint and end positions of the reverse rotation shown are significantly lower than those in the second comparative example. That is, at... Figure 10 In this embodiment, the motor speeds Va1 and Va2 are significantly lower than those of the motor speeds Vb1 and Vb2 in the second comparative example. Therefore, it can be seen that the reduction effect of the reversal noise is extremely high in this embodiment.

[0074] In the next second acceleration interval AS2 following the first acceleration interval AS1, the wiper control circuit 60 rapidly accelerates the motor speed to a second speed V2, which is faster than the first speed V1 (the second rapid acceleration portion). In the first half of this second acceleration interval AS2, the wiper control circuit 60 rapidly accelerates the motor speed to a speed 1 / 2V2, which is faster than the first speed V1 and half the speed of the second speed V2, using a second average acceleration AC2 that is more than twice the first average acceleration AC1. Therefore, Figures 6-10 The curve representing the solid line in this embodiment has a downwardly protruding bend BP2 at the boundary between the first acceleration interval AS1 and the second acceleration interval AS2. Figure 6 The shape of the symbol is omitted. The second speed V2 is set to the highest speed or a speed close to the selected position (LO, HI, or INT) of the wiper switch 66. Furthermore, in this embodiment, as an example, after the wiper control circuit 60 rapidly accelerates the motor speed to the second speed V2 in the second acceleration range AS2, it suppresses the acceleration of the motor speed to a constant or approximately constant (second constant speed portion) at the second speed V2. Therefore, Figures 6-8 The curve representing the solid line in this embodiment is formed in the second acceleration interval AS2 as a stepped shape or a shape similar to it. Therefore, as a whole, the first acceleration interval AS1 and the second acceleration interval AS2... Figures 6-8 The curve representing the solid line in this embodiment is a two-level stepped shape or a similar shape.

[0075] In the subsequent deceleration interval DS of the second acceleration interval AS2, the wiper control circuit 60 decelerates the motor speed, which has risen to the aforementioned maximum speed, to zero. In this embodiment, as an example, the wiper control circuit 60 rapidly decelerates the motor speed to zero in the latter half of the deceleration interval DS. Specifically, after maintaining the motor speed at the aforementioned maximum speed or equivalent for a certain period in the deceleration interval DS, the wiper control circuit 60 rapidly decelerates the motor speed to zero. In the latter half of this deceleration interval DS, the wiper control circuit 60 uses a second average acceleration AC2, which is more than twice the first average acceleration AC1, to rapidly decelerate the motor speed from a speed 1 / 2V2, which is half the second speed V2, to zero. The point at which the motor speed reaches zero at the end of this deceleration interval DS is the point at which the wiper rubber 31 reaches the opposite reversing position, and is also the starting point of the next first acceleration interval AS1. Furthermore, as... Figure 12 As shown by the solid line, it can also be configured to allow the motor speed to change smoothly in the first acceleration interval AS1, the second acceleration interval AS2, and the deceleration interval DS.

[0076] The following is based on Figures 12-14 As an example, the relationship between the motor speed, the pivot rotation speed (hereinafter referred to as "pivot speed"), and the sliding speed of the scraper rubber 31 relative to the wiping surface 12A (hereinafter referred to as "rubber sliding speed") in this embodiment will be explained. Figure 12 When the motor speed is controlled as shown by the solid line, the relationship between the pivot speed and time is as follows: Figure 13 As shown by the solid line, the relationship between the rubber sliding speed and time is as follows: Figure 14 As shown by the solid line. Additionally, in Figures 12-14 In the text, the double-dotted line indicates the case of the first comparative example mentioned above.

[0077] In this embodiment, the motor speed is rapidly reduced in the latter half of the deceleration range DS (see reference). Figure 12 The interval marked with the symbol DS1). In the latter half of this deceleration interval DS, both the pivot speed and the rubber sliding speed are also rapidly decelerated (see...). Figure 13 and Figure 14 (The interval marked with the symbol DS1). Therefore, as... Figure 15A As shown, the scraper rubber 31 maintains a low coefficient of friction relative to the surface being wiped 12A before reaching the reverse position P. As a result, vibration of the scraper rubber 31 caused by sliding at low speed against the surface being wiped 12A can be suppressed. Furthermore, in Figures 15A-15E In the middle, W represents rainwater.

[0078] In the first acceleration interval AS1, after the motor speed is rapidly accelerated to an extremely low first speed V1, the acceleration of the motor speed is suppressed (see reference). Figure 12 (The interval marked with the symbol AS1). In this first acceleration interval AS1, the pivot speed remains at an extremely low speed, while the rubber sliding speed remains at zero (see reference). Figure 13 and Figure 14 (The interval marked with the symbol AS1). Therefore, as... Figures 15B to 15D As shown, since the switching of the tilting direction of the lip 31A of the scraper rubber 31 is carried out at an extremely low speed, it is difficult to generate kinetic energy in the vertical direction of the scraper rubber 31 relative to the wiped surface 12A, that is, the kinetic energy that causes the vibration (vibration) of the scraper rubber 31.

[0079] In the first half of the second acceleration interval AS2, the motor speed is rapidly accelerated to a second speed V2, which is faster than the first speed V1 (refer to...). Figure 12 (The section marked with the symbol AS21). In the first half of this second acceleration section AS2, both the pivot velocity and the rubber sliding velocity are rapidly accelerated (see...). Figure 13 and Figure 14 (The interval marked with the symbol AS21). Therefore, as... Figure 15E As shown, since the tilting posture of the lip 31A of the scraper rubber 31 has ended, the scraper rubber 31 is rapidly accelerated while suppressing the vibration V in the vertical direction relative to the wiping surface 12A. This rapid acceleration lowers the coefficient of friction of the scraper rubber 31 relative to the wiping surface 12A, thus suppressing the vibration of the scraper rubber 31.

[0080] Furthermore, in this embodiment, the wiper control circuit 60 adjusts (fine-tunes) the motor speed in the first acceleration range AS1, the second acceleration range AS2, and the deceleration range DS based on information about the wiping mode selected by the wiper switch 66, information about the amount of rain detected by the rain sensor 67, and information about the vehicle speed detected by the vehicle speed sensor 68 (i.e., information about the load noise as ambient sound). Figure 16 The image shows an example of speed control variation of the motor, represented by a graph.

[0081] exist Figure 16In the example shown, with the wiper switch 66 in the low-speed operating mode selection position (LO), the wiper control circuit 60 changes the motor speed to three levels (LO+, LO, LO-) based on the detection results of the rain sensor 67 and the vehicle speed sensor 68. This adjusts the number of wipes (cpm) during LO mode operation according to the conditions. Specifically, in situations with heavy rainfall and high ambient noise, due to the so-called masking effect, vehicle occupants may have difficulty noticing the wiper noise. Therefore, the wiper control circuit 60 increases the motor speed and the wiping speed.

[0082] Specifically, in Figure 16 In the example shown, the wiper control circuit 60 is configured to operate under conditions of heavy rainfall or high-speed driving. Figure 16 The LO+ mode is indicated by a single-dot dash. In this LO+ mode, the motor speed in the first acceleration zone AS1 increases, and the wiping speed also increases. On the other hand, when driving at low speeds in light rain or when parked in heavy rain, the wiper control circuit 60 is configured to... Figure 16 The LO mode is indicated by a solid line. In this LO mode, the motor speed in the first acceleration zone AS1 decreases compared to the LO+ mode, and the wiping speed is also reduced. On the other hand, when parking in light rain, the wiper control circuit 60 is set to... Figure 16 The LO- mode is indicated by a double-dotted line. In the LO- mode, compared to the LO mode, the motor speed in the first acceleration zone AS1 decreases, and the wiping speed becomes lower. The wiping cycle T1 of the LO+ mode is shorter than the wiping cycle T of the LO mode, and the wiping cycle T2 of the LO- mode is longer than the wiping cycle T of the LO mode.

[0083] exist Figure 17 In this embodiment and the second comparative example described above (see reference 1), Figure 7 and Figure 8 The comparison of noise levels (within the dashed-dot line) is represented by a bar chart. Figure 17 In the diagram, the dashed line represents the ambient noise level. Under conditions of low rainfall and low ambient noise, in the INT mode of the second comparative example, the sound pressure level of the wiper reversing noise is higher than that of the motor operating noise. However, in this embodiment, the sound pressure level of the wiper reversing noise is lower in both the INT and LO modes than in the second comparative example. This is because, as in the second comparative example, simply reducing the motor speed near the wiper reversing position causes vibration of the wiper rubber, thus failing to sufficiently reduce the wiper reversing noise. In this second comparative example, noise is adjusted, for example, by adjusting the interval time.

[0084] On the other hand, under conditions where both rainfall and ambient noise are at a moderate level, in the LO mode of the second comparative example, the sound pressure of the wiper reversing sound is higher than that of the motor operating sound. However, in the LO mode of this embodiment, the sound pressure of the motor operating sound is slightly higher than that of the second comparative example, but the sound pressure of the wiper reversing sound is sufficiently lower. Therefore, in this embodiment, the sound pressure of the motor operating sound and the wiper reversing sound are optimally balanced, resulting in a lower overall noise level.

[0085] On the other hand, under conditions of heavy rainfall and high ambient noise, in the LO mode of the second comparative example, the sound pressure of the wiper reversing sound is higher than that of the motor operating sound. Conversely, in the LO+ mode of this embodiment, the sound pressure of both the motor operating sound and the wiper reversing sound is slightly higher than that of the second comparative example. This is because a masking effect is achieved; therefore, the reduction effect of the wiper reversing sound is reduced in this embodiment. Furthermore, the number of wipes per minute (cpm) is increased based on the amount of rainfall.

[0086] (Summary of this implementation method)

[0087] In this embodiment, during the first acceleration interval AS1, which switches the tilting direction of the lip 31A of the wiper rubber 31, the acceleration of the motor speed is suppressed after the motor speed rapidly accelerates from zero to a low speed (here, an extremely low speed) at a first speed V1. This rapid acceleration up to the first speed V1 suppresses the prolonged stopping time when the reverse rotation of the wipers 14 and 16 is felt. Furthermore, by setting the first speed V1 to a low speed and suppressing acceleration before reaching the second acceleration interval AS2, the reverse rotation noise caused by the switching can be reduced. Moreover, in the next second acceleration interval AS2 after the first acceleration interval AS1, the motor speed is rapidly accelerated to a second speed V2, which is higher than the first speed V1. By accelerating to this second speed V2, the coefficient of friction of the wiper rubber 31 relative to the wiped surface 12A becomes lower, thus suppressing the vibration of the wiper rubber 31.

[0088] Furthermore, since the structure drives the wiper motor 18 to reciprocate, compared to structures that convert the unidirectional rotational motion of the wiper motor into the reciprocating rotational motion of the wiper, the linkage mechanism 22 can be eliminated, the operating space can be reduced, and thus the vehicle's installation comfort can be improved. Additionally, since the wiping angle of the wipers 14 and 16 can be adjusted by controlling the rotation of the wiper motor 18, it is easy to suppress over-running and short-running of the wiper blades 28 and 30. Moreover, it is also easy to set the retracted position P3 of the wipers 14 and 16 to a lower position.

[0089] Furthermore, in this embodiment, the motor speed is rapidly reduced in the latter half of the deceleration interval DS. As a result, the scraper rubber 31 maintains a low coefficient of friction relative to the wiping surface 12A just before reaching the reversal position P. Consequently, vibration of the scraper rubber 31 caused by its sliding at low speed against the wiping surface 12A can be suppressed.

[0090] Furthermore, in this embodiment, after the motor speed is rapidly accelerated to a low speed V1 in the first acceleration interval AS1, acceleration is suppressed and the motor speed is set to a constant or approximately constant speed. Therefore, when the tilting direction of the lip 31A is switched, the motor speed is maintained at a low speed, thus effectively reducing the reversing noise caused by the switch. Moreover, by setting the motor speed to a constant or approximately constant speed, the rotation angle of the output shaft 32 at the end of the first acceleration interval AS1 can be easily and accurately detected, thus enabling high-precision control of the motor speed.

[0091] Furthermore, in this embodiment, the motor speed in the first acceleration zone AS1, the second acceleration zone AS2, and the deceleration zone DS is changed based on information about the wiping mode selected by the wiper switch 66, information about the amount of rain detected by the rain sensor 67, and information about the vehicle speed detected by the vehicle speed sensor 68. This allows for optimization of the wiping speed based on the amount of rain and load noise (ambient noise), reducing visual disturbance to occupants while the vehicle is in motion, and achieving an optimal balance between motor operating noise and wiper reversing noise.

[0092] Next, other embodiments of this disclosure will be described. Furthermore, for structures and functions substantially the same as those described in the embodiments, the same symbols as in the described embodiments will be used, and their descriptions will be omitted.

[0093] <Second Implementation>

[0094] exist Figure 18 The structure of a vehicle windshield wiper device 90 according to the second embodiment of this disclosure is illustrated in the diagram. In this vehicle windshield wiper device 90, the left and right windshield wipers 14 and 16 are configured to be driven reciprocally by separate windshield wiper motors 18 and 20, respectively. One end of the wiper arm 24 of the wiper 14 is fixed to the output shaft 32 of the wiper motor 18, and one end of the wiper arm 26 of the wiper 16 is fixed to the output shaft 34 of the wiper motor 20.

[0095] Wiper control circuits 60 and 62, respectively, are connected to wiper motors 18 and 20 to control their rotation. Wiper control circuit 60 includes a drive circuit 60A and a wiper ECU 60B, and wiper control circuit 62 includes a drive circuit 62A and a wiper ECU 62B. A rotation angle sensor 42, which detects the rotational speed and angle of the output shaft 32 of wiper motor 18, is connected to wiper ECU 60B. A rotation angle sensor 44, which detects the rotational speed and angle of the output shaft 34 of wiper motor 20, is also connected to wiper ECU 62B. The drive circuit 62A, wiper ECU 62B, and rotation angle sensor 44 have the same structure as the drive circuit 60A, wiper ECU 60B, and rotation angle sensor 42.

[0096] Wiper ECU 60B and wiper ECU 62B cooperate, for example, by communicating using a protocol such as LIN (Local Interconnect Network), to synchronize the operation of wiper motors 18 and 20. Thus, the wiper motors 18 and 20 are controlled to rotate at the same speed as in the first embodiment. In this embodiment, the structure other than that described above is basically the same as in the first embodiment. Therefore, in this embodiment, the same operational effects as in the first embodiment can also be obtained. Moreover, in this embodiment, since the linkage mechanism 22 is not required, vehicle installation comfort can be further improved.

[0097] <Third Implementation Method>

[0098] exist Figure 19 The diagram below illustrates a partial structure of a vehicle windshield wiper device according to a third embodiment of this disclosure. In this embodiment, the wiper motor 18 is a brushless motor, and the structure of the wiper control circuit 60 differs from that in the first embodiment. The wiper control circuit 60 includes: a drive circuit 60A that generates voltages applied to the terminals of the coils 18U, 18V, and 18W of the stator of the wiper motor 18; and a wiper ECU 60B that controls the switching on and off of the switching elements constituting the drive circuit 60A.

[0099] The rotor 92 of the wiper motor 18 is composed of three permanent magnets, one with S poles and one with N poles, configured to rotate in response to a rotating magnetic field generated in the coils of the stator. The magnetic field of the rotor 92 is detected by a Hall sensor 94. The Hall sensor 94 can also detect the magnetic field of a sensor magnet that corresponds to the polarity of the permanent magnets of the rotor 92 and is disposed separately from the rotor 92. The Hall sensor 94 detects the magnetic field of the rotor 92 or the sensor magnet as a magnetic field indicating the position of the rotor 92.

[0100] The Hall sensor 94 is a sensor used to detect the position of the rotor 92 by detecting the magnetic field formed by the rotor 92 or the sensor magnet. The Hall sensor 94 includes three Hall elements corresponding to U, V, and W. The Hall sensor 94 outputs the change in the magnetic field generated by the rotation of the rotor 92 as a signal of voltage change that approximates a sine wave.

[0101] The signal output by Hall sensor 94 is input to the wiper ECU 60B, which is a control circuit. The wiper ECU 60B is an integrated circuit that controls the power supplied from battery 80, which serves as a power source, through backup circuit 100.

[0102] The analog waveform signal input from Hall sensor 94 to wiper ECU 60B is input to Hall sensor edge detection unit 106, which includes circuitry that converts analog signals from comparators or similar devices located within wiper ECU 60B into digital signals. In Hall sensor edge detection unit 106, the input analog waveform is converted into a digital waveform, and edge portions are detected from the digital waveform.

[0103] Information about the digital waveform and edges is input to the motor position estimation unit 104, and the position of the rotor 92 is calculated. The calculated position information of the rotor 92 is input to the energization control unit 108.

[0104] Additionally, a signal indicating the rotational speed of the wiper motor 18 (rotor 92) is input from the wiper switch 66 to the command value calculation unit 102 of the wiper ECU 60B. The command value calculation unit 102 extracts commands related to the rotational speed of the wiper motor 18 based on the signal input from the wiper switch 66 and inputs them to the power-on control unit 108.

[0105] The power-on control unit 108 calculates the phase of the voltage that varies based on the position of the magnetic poles of the rotor 92 calculated by the motor position estimation unit 104, and determines the drive duty cycle value based on the calculated phase and the rotational speed of the rotor 92 indicated by the wiper switch 66. Furthermore, the power-on control unit 108 generates a pulse signal (PWM signal) corresponding to the drive duty cycle value and outputs it to the drive circuit 60A for PWM control. Through this PWM control, the drive circuit 60A generates a voltage that varies at a time based on the position of the magnetic poles of the rotor 92 and applies it to the coils 18U, 18V, and 18W of the stator 18. A rotating magnetic field that causes the rotor 92 to rotate is generated in the coils 18U, 18V, and 18W to which this voltage is applied.

[0106] The drive circuit 60A consists of a three-phase (U-phase, V-phase, W-phase) inverter. For example... Figure 19As shown, the drive circuit 60A includes three N-channel field-effect transistors (MOSFETs) 96U, 96V, and 96W (hereinafter referred to as "FET96U, 96V, and 96W") that serve as upper-level switching elements, and three N-channel field-effect transistors 98U, 98V, and 98W (hereinafter referred to as "FET 98U, 98V, and 98W") that serve as lower-level switching elements. Furthermore, FETs 96U, 96V, and 96W and FETs 98U, 98V, and 98W are collectively referred to as "FET 96" and "FET 98" when no distinction is necessary; when a distinction is required, they are described using the symbols "U", "V", and "W".

[0107] The source of FET 96U and the drain of FET 98U in FET 96 and FET 98 are connected to the terminals of coil 18U, the source of FET 96V and the drain of FET 98V are connected to the terminals of coil 18V, and the source of FET 96W and the drain of FET 98W are connected to the terminals of coil 18W.

[0108] The gates of FETs 96 and FET 98 are connected to the power-on control unit 108 and are input with PWM signals. When a high-level PWM signal is input to the gate, FETs 96 and FET 98 are in the ON state, and current flows from the drain to the source. Conversely, when a low-level PWM signal is input to the gate, they become ON, and current no longer flows from the drain to the source.

[0109] Furthermore, the wiper control circuit 60 in this embodiment includes a battery 80, a noise reduction coil 110, and smoothing capacitors 112A and 112B. The battery 80, the noise reduction coil 110, and the smoothing capacitors 112A and 112B constitute a generally DC power supply.

[0110] Furthermore, a chip thermistor RT is mounted on the substrate of the wiper control circuit 60 in this embodiment. A control voltage Vcc is applied to one end of the chip thermistor RT via resistor R1, and the other end is grounded. The temperature of the substrate is detected as the resistance value. The chip thermistor RT used in this embodiment is an NTC (Negative Temperature Coefficient) thermistor whose resistance decreases with increasing temperature; the resistance value of the chip thermistor RT decreases as the temperature rises. Alternatively, a PTC (Positive Temperature Coefficient) thermistor, whose resistance increases with increasing temperature, can also be used by using an inverting circuit.

[0111] A chip thermistor RT and a resistor R1 form a voltage divider circuit, outputting a voltage that varies based on the resistance value of the chip thermistor RT from one end connected to the resistor R1. The voltage output from one end of the chip thermistor RT is compared with an overheating determination value in the power-on control unit 108. If the voltage output from one end of the chip thermistor RT is below the overheating determination value, the wiper control circuit 60 is determined to be in an overheated state. As described above, since the chip thermistor RT in this embodiment is of the type whose resistance decreases with increasing temperature, the voltage output from the output terminal of the voltage divider circuit formed by the resistor R1 and the chip thermistor RT, i.e., one end of the chip thermistor RT, decreases as the temperature rises. The power-on control unit 108 determines that the circuit is overheated when the voltage output from one end of the chip thermistor RT is below the overheating determination value. The overheating threshold varies depending on the components mounted on the substrate and the position of the chip thermistor RT. However, as an example, it is the voltage output by the voltage divider circuit of the chip thermistor RT and resistor R1 at 145°C.

[0112] Additionally, a current detection unit 114 is provided between each source of FETs 98U, 98V, and 98W and the battery 80. The current detection unit 114 includes a shunt resistor with a resistance of approximately 0.2mΩ to several Ω and an amplifier that amplifies the potential difference across the shunt resistor and outputs a voltage value proportional to the current in the shunt resistor as a signal. The signal output by the amplifier is input to the power-on control unit 108. In the power-on control unit 108, the signal output by the current detection unit 114 is compared with an overcurrent determination value. If the signal output by the current detection unit 114 is higher than or equal to the overcurrent determination value, the motor current is determined to be an overcurrent. Furthermore, although... Figure 19 Although not illustrated, a voltage sensor for detecting the voltage of the battery 80 is mounted on the substrate of the wiper control circuits 60, 60. In this embodiment, the structure other than that described above is the same as in the first embodiment. In this embodiment, it can also achieve essentially the same functional effects as the first embodiment.

[0113] <Fourth Implementation>

[0114] exist Figure 20 In the figure, a graph is used to show the relationship between the speed of the electric motor and time of the vehicle windshield wiper device according to the fourth embodiment of this disclosure. Figure 21The graph in the diagram illustrates the relationship between the motor speed and the output shaft angle of the vehicle wiper device according to the fourth embodiment. In this embodiment, similar to the first embodiment, the wiper control circuit 60 accelerates the motor speed from zero to a low first speed V1 with a first average acceleration AC1 during the first acceleration interval AS1. However, unlike the first embodiment, the wiper control circuit 60 does not suppress the acceleration of the motor speed after rapidly accelerating it from zero to the first speed V1 during the first acceleration interval AS1; instead, it accelerates the motor speed from zero to the first speed V1 with a substantially constant acceleration.

[0115] Furthermore, in this embodiment, similarly to the first embodiment, the wiper control circuit 60 rapidly accelerates the motor speed to a speed 1 / 2V2, which is faster than the first speed V1 and half the speed of the second speed V2, during the first half of the second acceleration range AS2, using a second average acceleration AC2 that is more than twice the first average acceleration AC1. Similarly, in the deceleration range DS, also similarly to the first embodiment, the wiper control circuit 60 rapidly decelerates the motor speed from a speed 1 / 2V2, which is half the speed of the second speed V2, to zero during the second half of the deceleration range DS, using a second average acceleration AC2 that is more than twice the first average acceleration AC1.

[0116] In this embodiment, by setting the first speed V1 to a low speed, the reversing noise caused by the switching of the tilting direction of the lip 31A can also be reduced. Furthermore, in the second acceleration interval AS2, the motor speed is accelerated to a speed 1 / 2V2, which is half the second speed V2, at a second average acceleration AC2, which is more than twice the first average acceleration. By accelerating to this speed 1 / 2V2, the coefficient of friction of the scraper rubber 31 relative to the surface being wiped becomes lower, thus suppressing the vibration of the scraper rubber 31.

[0117] Furthermore, while the above embodiments employ a structure that uses the detection results of the rain sensor 67 and the vehicle speed sensor 68 to change the speed of the electric motor, the invention is not limited thereto. The windshield wiper device for vehicles disclosed herein can also be applied to vehicles that do not include either or both of the rain sensor and the vehicle speed sensor.

[0118] Furthermore, the structure of the linkage mechanism 22 in the first embodiment described above is only one example and can be modified appropriately.

[0119] Furthermore, in the above embodiments, the case where the wipers 14 and 16 are connected in series has been described, but the wipers may also be symmetrical and rotate in opposite directions to wipe.

[0120] While this disclosure has been described based on embodiments, it should be understood that this disclosure is not limited to the above embodiments and structures. This disclosure also includes various modifications and equivalent variations. Furthermore, various combinations and arrangements, and consequently, combinations and arrangements containing only one element, or more than or less thereof, also fall within the scope and spirit of this disclosure.

Claims

1. A windshield wiper device for vehicles, comprising: Windshield wiper motor; The control unit drives the wiper motor to rotate reciprocally and controls the rotation speed of the wiper motor. as well as The windshield wiper rotates reciprocally due to the reciprocating rotation of the wiper motor, using a squeegee rubber blade to repeatedly wipe the surface of the vehicle. The direction of the blade's lip is switched when the rotation direction is reversed. In the first acceleration interval where the tilting direction of the lip is switched, the control unit accelerates the rotational speed of the wiper motor from zero to a low first speed with a first average acceleration. In the first half of the second acceleration interval following the first acceleration interval, the control unit rapidly accelerates the rotational speed to a speed that is higher than the first speed and half the second speed with an average acceleration that is more than twice the first average acceleration.

2. The vehicle windshield wiper device as described in claim 1, characterized in that, In the first acceleration zone, the tilting direction of the lip is switched at the midpoint of the long side of the scraper rubber.

3. The vehicle windshield wiper device as described in claim 1 or 2, characterized in that, In the latter half of the deceleration interval following the second acceleration interval, the control unit rapidly decelerates the rotational speed from half the speed of the second speed to zero with an average acceleration of more than twice the first average acceleration.

4. The vehicle windshield wiper device as described in claim 1 or 2, characterized in that, After the control unit rapidly accelerates the rotational speed to the first speed in the first acceleration range, it suppresses the acceleration and sets the rotational speed to a constant or approximately constant.

5. The vehicle windshield wiper device as described in claim 1 or 2, characterized in that, The control unit changes the rotation speed in each of the intervals based on information about the wiping mode selected by the wiper switch, information about the amount of rain detected by the rain sensor, and information about the vehicle speed detected by the vehicle speed sensor.

6. A control method for a vehicle windshield wiper device, In the control method of the vehicle windshield wiper device, the wiper is rotated reciprocally by transmitting the reciprocating rotation of the wiper motor, and the wiper blade rubber is used to reciprocate to wipe the surface of the vehicle. Furthermore, when the rotation direction of the wiper is reversed, the tilting direction of the lip of the wiper blade rubber is switched. In the first acceleration interval where the tilting direction of the lip is switched, the rotational speed of the wiper motor is accelerated from zero to a low first speed with a first average acceleration. In the first half of the second acceleration interval following the first acceleration interval, the rotational speed is rapidly accelerated to a speed that is higher than the first speed and half the second speed with an average acceleration that is more than twice the first average acceleration.

7. The control method for a vehicle windshield wiper device as described in claim 6, characterized in that, In the first acceleration zone, the tilting direction of the lip is switched at the midpoint of the long side of the scraper rubber.

8. The control method for a vehicle windshield wiper device as described in claim 6 or 7, characterized in that, In the latter half of the deceleration interval following the second acceleration interval, the rotational speed is rapidly reduced from half the speed of the second speed to zero with an average acceleration of more than twice the first average acceleration.

9. The control method for a vehicle windshield wiper device as described in claim 6 or 7, characterized in that, After rapidly accelerating the rotational speed to the first speed in the first acceleration range, the acceleration is suppressed and the rotational speed is set to constant or approximately constant.

10. The control method for a vehicle windshield wiper device as described in claim 6 or 7, characterized in that, The rotation speed of each of the aforementioned intervals is changed based on information about the wiping mode selected by the wiper switch, information about the amount of rain detected by the rain sensor, and information about the vehicle speed detected by the vehicle speed sensor.

Images