Hydraulic control unit and diagnostic method

Abstract

To appropriately diagnose an abnormality of a power supply line.SOLUTION: In a fluid pressure control unit and a diagnosis method according to the present invention, in a power supply line diagnosis, a diagnosis unit of a control device generates one rectangular wave pulse current in which a current value of current applied to a solenoid valve transitions in the order of a first current value, a second current value larger than the first current value, and a third current value smaller than the second current value. The diagnosis unit diagnoses an abnormality of a power supply line based on results of a first resistance value evaluation in which a resistance value of the power supply line is evaluated based on a voltage change amount of the power supply line before and after the current value transitions from the first current value to the second current value, and a second resistance value evaluation in which the resistance value is evaluated based on the voltage change amount before and after the current value transitions from the second current value to the third current value. In at least one of the first resistance value evaluation and the second resistance value evaluation, a plurality of voltage change amounts in which at least one of a start time point and an end time point of the voltage change is different from each other are acquired, and a plurality of resistance value evaluations are performed.SELECTED DRAWING: Figure 8

Description

【Technical Field】 【0001】 This disclosure relates to a hydraulic control unit and a diagnostic method that can appropriately diagnose abnormalities in a power line. 【Background Art】 【0002】 Vehicles are provided with a hydraulic control unit for controlling the braking force generated on the wheels (see, for example, Patent Document 1). In the hydraulic control unit, the hydraulic pressure of the brake fluid is controlled by a hydraulic control mechanism including solenoid valves. 【Prior Art Documents】 【Patent Documents】 【0003】 【Patent Document 1】 Japanese Patent Application Laid-Open No. 2018-8674 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0004】 The hydraulic control unit is electrically connected to a power source via a power line such as a wire harness. Each device such as a solenoid valve in the hydraulic control unit operates using the electric power supplied from the power source via the power line. When an abnormality in the power line (for example, aging deterioration) occurs and the resistance value of the power line becomes excessively large, it becomes difficult to operate the hydraulic control unit normally. Therefore, it is desired to appropriately diagnose an abnormality in the power line. 【0005】 The present invention has been made against the background of the above problems, and aims to obtain a hydraulic control unit and a diagnostic method that can appropriately diagnose an abnormality in a power line. 【Means for Solving the Problems】 【0006】 The hydraulic control unit according to the present invention is a hydraulic control unit used in a vehicle brake system, comprising: a hydraulic control mechanism including a solenoid valve that is electrically connected to a power source via a power line and controls the hydraulic pressure generated in a wheel cylinder; and a control device that controls the operation of the hydraulic control mechanism, wherein the control device includes a diagnostic unit that performs a power line diagnosis to diagnose an abnormality in the power line based on the voltage change of the power line when the current applied from the power source to the solenoid valve via the power line is changed, and the diagnostic unit, in the power line diagnosis, determines that the current value of the current applied to the solenoid valve changes in the order of a first current value, a second current value greater than the first current value, and a third current value less than the second current value, forming a single rectangular wave A pulse current is generated, and a first resistance value evaluation is performed to evaluate the resistance value of the power line based on the amount of voltage change of the power line before and after the current value changes from the first current value to the second current value in the pulse current, and a second resistance value evaluation is performed to evaluate the resistance value based on the amount of voltage change of the power line before and after the current value changes from the second current value to the third current value in the pulse current, and an abnormality in the power line is diagnosed based on the results of the first resistance value evaluation and the second resistance value evaluation, and in at least one of the first resistance value evaluation and the second resistance value evaluation, a plurality of voltage change amounts are obtained in which at least one of the start time and end time of the voltage change is different from each other, and the resistance value evaluation is performed in a plurality of ways. 【0007】 The diagnostic method according to the present invention is a diagnostic method for a hydraulic control unit used in a vehicle brake system, wherein the hydraulic control unit comprises a hydraulic control mechanism including a solenoid valve that is electrically connected to a power source via a power line and controls the hydraulic pressure generated in a wheel cylinder, and a control device that controls the operation of the hydraulic control mechanism, wherein the diagnostic unit of the control device performs a power line diagnosis to diagnose an abnormality in the power line based on the voltage change of the power line when the current applied from the power source to the solenoid valve via the power line is changed, and the diagnostic unit determines that in the power line diagnosis, the current value of the current applied to the solenoid valve changes in the order of a first current value, a second current value greater than the first current value, and a third current value less than the second current value. A rectangular wave-shaped pulse current is generated, and a first resistance value evaluation is performed to evaluate the resistance value of the power line based on the amount of voltage change of the power line before and after the current value changes from the first current value to the second current value in the pulse current, and a second resistance value evaluation is performed to evaluate the resistance value based on the amount of voltage change of the power line before and after the current value changes from the second current value to the third current value in the pulse current, and an abnormality in the power line is diagnosed based on the results of the first resistance value evaluation and the second resistance value evaluation, and in at least one of the first resistance value evaluation and the second resistance value evaluation, a plurality of voltage change amounts are obtained in which at least one of the start time and end time of the voltage change is different from each other, and the resistance value evaluation is performed in a plurality of ways. [Effects of the Invention] 【0008】 The hydraulic control unit and diagnostic method according to the present invention comprises a hydraulic control mechanism including a solenoid valve that is electrically connected to a power source via a power line and controls the hydraulic pressure generated in a wheel cylinder, and a control device that controls the operation of the hydraulic control mechanism, wherein the diagnostic unit of the control device performs a power line diagnosis to diagnose an abnormality in the power line based on the voltage change of the power line when the current applied to the solenoid valve from the power source via the power line is changed, and the diagnostic unit determines in the power line diagnosis that the current value of the current applied to the solenoid valve changes in the order of a first current value, a second current value greater than the first current value, and a third current value less than the second current value, forming a single rectangular wave A pulsed current is generated, and a first resistance evaluation is performed to assess the resistance of the power line based on the voltage change of the power line before and after the current value in the pulsed current transitions from a first current value to a second current value. A second resistance evaluation is performed to assess the resistance based on the voltage change before and after the current value in the pulsed current transitions from a second current value to a third current value. Based on the results of the first and second resistance evaluations, an abnormality in the power line is diagnosed. In at least one of the first and second resistance evaluations, multiple voltage change values ​​are obtained where at least one of the start and end points of the voltage change is different from each other, and multiple resistance evaluations are performed. As a result, many resistance values ​​can be evaluated using a single pulsed current. Therefore, an abnormality in the power line can be appropriately diagnosed. [Brief explanation of the drawing] 【0009】 [Figure 1] This is a schematic diagram showing the general configuration of a vehicle according to an embodiment of the present invention. [Figure 2] This is a schematic diagram showing the general configuration of a brake system according to an embodiment of the present invention. [Figure 3] This figure shows an example of the electrical connection relationships between components, including a hydraulic control unit according to an embodiment of the present invention. [Figure 4] This is a block diagram showing an example of the functional configuration of a control device according to an embodiment of the present invention. [Figure 5]This flowchart shows an example of the processing flow related to power line diagnosis performed by a control device according to an embodiment of the present invention. [Figure 6] This graph shows an example of the transitions of various state variables in a first example of power line diagnostics according to an embodiment of the present invention. [Figure 7] This graph shows an example of the transitions of various state variables in a comparative example to the first example of power line diagnosis according to an embodiment of the present invention. [Figure 8] This graph shows an example of the transitions of various state variables in a second example of power line diagnostics according to an embodiment of the present invention. [Modes for carrying out the invention] 【0010】 The hydraulic control unit and diagnostic method according to the present invention will be described below with reference to the drawings. 【0011】 Although the following description focuses on a hydraulic control unit used in two-wheeled motorcycles (see vehicle 100 in Figure 1), the hydraulic control unit according to the present invention may be applied to other saddle-type vehicles besides two-wheeled motorcycles. A saddle-type vehicle refers to a vehicle that a rider straddles and rides on. Examples of saddle-type vehicles include motorcycles (two-wheeled vehicles, three-wheeled vehicles), bicycles, buggies, etc. Motorcycles include vehicles powered by engines, vehicles powered by electric motors, etc. Examples of motorcycles include motorcycles, scooters, electric scooters, etc. A bicycle refers to a vehicle that can be propelled on the road by the rider's pedaling force applied to the pedals. Bicycles include ordinary bicycles, electric assist bicycles, electric bicycles, etc. As will be described later, some of the embodiments described below may also be applied to other vehicles other than saddle-type vehicles (for example, four-wheeled vehicles, etc.). 【0012】 Furthermore, the configuration and operation described below are merely examples, and the hydraulic control unit and diagnostic method according to the present invention are not limited to such configurations and operations. 【0013】 Furthermore, in the following, identical or similar explanations have been simplified or omitted as appropriate. Also, in each figure, identical or similar components or parts have either had their reference numerals omitted or the same reference numerals have been used. In addition, detailed structures have been simplified or omitted as appropriate. 【0014】 <Vehicle Configuration> The configuration of a vehicle 100 according to an embodiment of the present invention will be described with reference to Figures 1 to 4. 【0015】 Figure 1 is a schematic diagram showing the general configuration of vehicle 100. Vehicle 100 is a two-wheeled motorcycle that corresponds to an example of a vehicle according to the present invention. As shown in Figure 1, vehicle 100 comprises a body 1, handlebars 2, front wheel 3, rear wheel 4, hydraulic control unit 5, and notification device 6. Vehicle 100 also comprises a brake system 10. The brake system 10 includes a first brake operating unit 11, a front wheel braking mechanism 12, a second brake operating unit 13, and a rear wheel braking mechanism 14. 【0016】 The handlebars 2 are rotatably held on the body 1. The front wheels 3 are rotatably held on the body 1 together with the handlebars 2. The rear wheels 4 are rotatably held on the body 1. The hydraulic control unit 5 is for controlling the braking force generated on the wheels of the vehicle 100. The hydraulic control unit 5 is included in the brake system 10. Details of the hydraulic control unit 5 will be described later. The notification device 6 notifies various information. For example, the notification device 6 may be a display device such as a lamp or an audio output device. 【0017】 The braking system 10 specifically includes a hydraulic control unit 5 in addition to a first brake operation unit 11, a front-wheel braking mechanism 12, a second brake operation unit 13, and a rear-wheel braking mechanism 14. The first brake operation unit 11 is provided, for example, on the handle 2 and is operated by the rider's hand. The first brake operation unit 11 is, for example, a brake lever. The front-wheel braking mechanism 12 brakes the front wheels 3 in conjunction with at least the first brake operation unit 11. The second brake operation unit 13 is provided, for example, at the lower part of the body 1 and is operated by the rider's foot. The second brake operation unit 13 is, for example, a brake pedal. The rear-wheel braking mechanism 14 brakes the rear wheels 4 in conjunction with at least the second brake operation unit 13. The hydraulic control unit 5 is a unit that functions to control the braking force applied to the front wheels 3 by the front-wheel braking mechanism 12 and the braking force applied to the rear wheels 4 by the rear-wheel braking mechanism 14. 【0018】 FIG. 2 is a schematic diagram showing the schematic configuration of the braking system 10. As shown in FIG. 2, each of the front-wheel braking mechanism 12 and the rear-wheel braking mechanism 14 includes a master cylinder 21 incorporating a piston (not shown), a reservoir 22 attached to the master cylinder 21, a brake caliper 23 held by the body 1 and having a brake pad (not shown), a wheel cylinder 24 provided on the brake caliper 23, a main flow path 25 for circulating the brake fluid of the master cylinder 21 to the wheel cylinder 24, and a sub-flow path 26 for discharging the brake fluid of the wheel cylinder 24. As shown in FIG. 2, in the braking system 10, the number of wheel cylinders 24 communicating with one master cylinder 21 is one. 【0019】 However, the number of wheel cylinders 24 communicating with one master cylinder 21 may be two or more. Also, a supply flow path for supplying the brake fluid of the master cylinder 21 to the sub-flow path 26 may be further provided. Also, one of the front-wheel braking mechanism 12 and the rear-wheel braking mechanism 14 may be omitted. 【0020】 The main passage 25 is a passage that connects the master cylinder 21 and the wheel cylinder 24. The main passage 25 is equipped with a suction valve (EV) 31. The secondary passage 26 bypasses the main passage 25 between the wheel cylinder 24 side and the master cylinder 21 side relative to the suction valve 31. The secondary passage 26 is equipped with, in order from the upstream side, a release valve (AV) 32, an accumulator 33, and a pump 34. 【0021】 The suction valve 31 and the release valve 32 are solenoid valves that control the hydraulic pressure generated in the wheel cylinder 24. The suction valve 31 is an open solenoid valve when de-energized. The suction valve 31 closes when energized. Specifically, the suction valve 31 closes when the current applied to it becomes sufficiently large. The current applied to the suction valve 31 in the closed state is controlled to several different values. In other words, the current applied to the suction valve 31 can be changed while maintaining the suction valve 31 in a closed state. The release valve 32 is an solenoid valve that is closed when de-energized. The release valve 32 opens when energized. Specifically, the release valve 32 opens when the current applied to it becomes sufficiently large. 【0022】 The hydraulic control unit 5 comprises a hydraulic control mechanism 51 for controlling the hydraulic pressure of the brake fluid and a control device 52 for controlling the operation of the hydraulic control mechanism 51. The hydraulic control mechanism 51 includes components such as the aforementioned suction valve 31, release valve 32, accumulator 33, and pump 34. The hydraulic control mechanism 51 includes a base body 51a in which the aforementioned main flow path 25 and sub-flow path 26 are formed, and the above components are provided on the base body 51a. For example, a control board is used as the control device 52. 【0023】 The base body 51a may be formed from a single member or from multiple members. Furthermore, if the base body 51a is formed from multiple members, each component may be provided on a different member. 【0024】 The operation of the hydraulic control mechanism 51 is controlled by the control device 52, thereby controlling the braking force generated on the front wheels 3 by the front wheel braking mechanism 12 and the braking force generated on the rear wheels 4 by the rear wheel braking mechanism 14. The control device 52 controls the operation of the hydraulic control mechanism 51, for example, according to the driving conditions of the vehicle 100. 【0025】 For example, in the normal state (i.e., when anti-lock brake control, etc., described later is not performed), the control device 52 opens the loading valve 31 and closes the release valve 32. In this state, when the first brake operation unit 11 is operated, in the front wheel braking mechanism 12, the piston (not shown) of the master cylinder 21 is pushed in, increasing the hydraulic pressure of the brake fluid in the wheel cylinder 24, and the brake pads (not shown) of the brake caliper 23 are pressed against the rotor 3a of the front wheel 3, thereby applying braking force to the front wheel 3. Also, when the second brake operation unit 13 is operated, in the rear wheel braking mechanism 14, the piston (not shown) of the master cylinder 21 is pushed in, increasing the hydraulic pressure of the brake fluid in the wheel cylinder 24, and the brake pads (not shown) of the brake caliper 23 are pressed against the rotor 4a of the rear wheel 4, thereby applying braking force to the rear wheel 4. 【0026】 Anti-lock brake control is performed, for example, when a wheel (specifically, the front wheel 3 or the rear wheel 4) locks or is likely to lock, and reduces the braking force applied to the wheel without the rider operating the brake lever. For example, when anti-lock brake control is performed, the control device 52 closes the loading valve 31 and opens the release valve 32. In this state, the control device 52 drives the pump 34, which reduces the hydraulic pressure of the brake fluid in the wheel cylinder 24, thereby reducing the braking force applied to the wheel. 【0027】 The control device 52 performs various controls using various information detected in the vehicle 100. For example, as shown in Figure 1, the vehicle 100 is equipped with a front wheel speed sensor 41 and a rear wheel speed sensor 42. The detection results from these sensors are output to the control device 52. 【0028】 The front wheel speed sensor 41 is a wheel speed sensor that detects the wheel speed of the front wheel 3 (for example, the number of rotations per unit time [rpm] or the distance traveled per unit time [km / h] of the front wheel 3, etc.) and outputs the detection result. The front wheel speed sensor 41 may also detect other physical quantities that can be substantially converted to the wheel speed of the front wheel 3. The front wheel speed sensor 41 is installed on the front wheel 3. 【0029】 The rear wheel speed sensor 42 is a wheel speed sensor that detects the wheel speed of the rear wheel 4 (for example, the number of rotations per unit time [rpm] or the distance traveled per unit time [km / h] of the rear wheel 4, etc.) and outputs the detection result. The rear wheel speed sensor 42 may also detect other physical quantities that can be substantially converted to the wheel speed of the rear wheel 4. The rear wheel speed sensor 42 is installed on the rear wheel 4. 【0030】 Figure 3 shows an example of the electrical connection relationships between components, including the hydraulic control unit 5. As shown in Figure 3, the hydraulic control unit 5 is electrically connected to power supply B1 via a power line L1, such as a wire harness. Each device in the hydraulic control unit 5 operates using power supplied from power supply B1 via power line L1. In Figure 3, only the part related to the suction valve 31, which is one of the components in the hydraulic control unit 5 that operates using power supplied from power supply B1, is shown. The suction valve 31 is electrically connected to power supply B1 via power line L1. However, other components in the hydraulic control unit 5 other than the suction valve 31 (e.g., the release valve 32) are also electrically connected to power supply B1 via power line L1. 【0031】 As shown in Figure 3, the hydraulic control unit 5 includes a switching element 35 and a voltage sensor 43. Signal input and output are possible between the suction valve 31, the switching element 35, and the voltage sensor 43 and the control device 52. 【0032】 The valve 31 is electrically connected to the power supply B1 via a switching element 35. The switching element 35 switches whether or not power is supplied at the installation location. When the switching element 35 is in the closed state, current can pass through the switching element 35. On the other hand, when the switching element 35 is in the open state, current cannot pass through the switching element 35. The switching element 35 is, for example, a semiconductor relay including a field-effect transistor (FET). However, the configuration of the switching element 35 is not particularly limited, and it does not have to be a semiconductor relay. 【0033】 The control device 52 can stop the application of current from the power supply B1 to the valve 31 by keeping the switching element 35 in a closed state. On the other hand, the control device 52 can apply current from the power supply B1 to the valve 31 by opening the switching element 35. The control device 52 can control the current applied to the valve 31 to several different values ​​by, for example, switching the switching element 35 between an open state and a closed state and adjusting the duration of the open state of the switching element 35 per unit time. 【0034】 The voltage sensor 43 detects the voltage of the power line L1. Specifically, the voltage sensor 43 detects the voltage in the power line connecting the power line L1 and the suction valve 31 within the hydraulic control unit 5 as the voltage of the power line L1. In other words, the voltage detected by the voltage sensor 43 is the voltage of the power supply B1 minus the voltage drop due to the resistance of the power line L1 (in other words, the voltage at the end of the power line L1 on the hydraulic control unit 5 side). Therefore, as the resistance of the power line L1 increases, the voltage obtained by subtracting the voltage drop decreases. In the example in Figure 3, the voltage on the power line L1 side is detected by the voltage sensor 43 relative to the switching element 35, but the voltage sensor 43 may also detect the voltage on the suction valve 31 side relative to the switching element 35. 【0035】 Figure 4 is a block diagram showing an example of the functional configuration of the control device 52. For example, part or all of the control device 52 is composed of a microcontroller, a microprocessor unit, etc. Also, for example, part or all of the control device 52 may be composed of updatable components such as firmware, or it may be a program module executed by commands from a CPU, etc. The control device 52 may be a single unit, or it may be divided into multiple units. 【0036】 As shown in Figure 4, the control device 52 includes, for example, an acquisition unit 52a, a control unit 52b, and a diagnostic unit 52c. 【0037】 The acquisition unit 52a acquires information from various devices mounted on the vehicle 100. For example, the acquisition unit 52a acquires information from the front wheel speed sensor 41, the rear wheel speed sensor 42, and the voltage sensor 43. 【0038】 The control unit 52b controls the operation of various devices within the vehicle 100. For example, the control unit 52b performs notification operations to the rider by controlling the operation of the notification device 6. Also, for example, the control unit 52b controls the braking force generated on the wheels of the vehicle 100 by controlling the operation of each component of the hydraulic control unit 5 (specifically, the fill valve 31, the release valve 32, the pump 34, and the switching element 35). 【0039】 The diagnostic unit 52c performs a power line diagnosis to diagnose abnormalities in the power line L1. As described above, if the resistance value of the power line L1 becomes excessively high due to an abnormality in the power line L1, it becomes difficult to operate the hydraulic control unit 5 normally. In this embodiment, as will be described later, abnormalities in the power line L1 can be appropriately diagnosed by making improvements to the power line diagnosis. 【0040】 <Operation of the hydraulic control unit> The operation of the hydraulic control unit 5 according to an embodiment of the present invention will be described with reference to Figures 5 to 8. 【0041】 Figure 5 is a flowchart showing an example of the processing flow for power line diagnosis performed by the control device 52 (specifically, the diagnostic unit 52c). Step S101 in Figure 5 corresponds to the start of the control flow shown in Figure 5. Step S108 in Figure 5 corresponds to the end of the control flow shown in Figure 5. Details of the power line diagnosis will be described later with reference to Figures 6 to 8. 【0042】 When the control flow shown in Figure 5 begins, in step S102, the diagnostic unit 52c determines whether the conditions for starting the power line diagnosis have been met. For example, the conditions for starting the power line diagnosis include the vehicle speed of vehicle 100 exceeding the reference vehicle speed after the vehicle 100 has started moving. The vehicle speed of vehicle 100 can be determined, for example, based on the detection results of the front wheel speed sensor 41 and the rear wheel speed sensor 42. The reference vehicle speed is set, for example, to a speed at which it can be determined that the rider intends to accelerate vehicle 100. 【0043】 If it is determined that the conditions for starting the power line diagnosis are not met (step S102 / NO), step S102 is repeated. On the other hand, if it is determined that the conditions for starting the power line diagnosis are met (step S102 / YES), the process proceeds to step S103. 【0044】 In step S103, the diagnostic unit 52c determines whether the voltage of the power line L1 is stable or not. For example, the diagnostic unit 52c determines that the voltage of the power line L1 is stable if the difference between the minimum and maximum voltages of the power line L1 within a set time is less than or equal to a reference value. On the other hand, the diagnostic unit 52c determines that the voltage of the power line L1 is unstable if the difference between the minimum and maximum voltages of the power line L1 within a set time is greater than a reference value. 【0045】 If it is determined that the voltage of power line L1 is unstable (step S103 / NO), the process returns to step S102. On the other hand, if it is determined that the voltage of power line L1 is stable (step S103 / YES), the process proceeds to step S104. 【0046】 In step S104, the diagnostic unit 52c performs a power line diagnosis. In the power line diagnosis, the diagnostic unit 52c diagnoses an abnormality in the power line L1 based on the voltage change in the power line L1 when the current applied to the solenoid valve (e.g., the suction valve 31) of the hydraulic control unit 5 is changed. The power line diagnosis determines whether the power line L1 is normal or not. If the power line L1 is normal, it corresponds to the case where the resistance value of the power line L1 is not excessively high. On the other hand, if the power line L1 is abnormal, it corresponds to the case where the resistance value of the power line L1 is excessively high. Details of the power line diagnosis will be described later with reference to Figures 6 to 8. 【0047】 In step S105, the diagnostic unit 52c determines whether or not the power line L1 has been diagnosed as normal. If the power line L1 is diagnosed as normal (step S105 / YES), the control flow shown in Figure 5 ends. On the other hand, if the power line L1 is not diagnosed as normal (step S105 / NO), the process proceeds to step S106. 【0048】 In step S106, the diagnostic unit 52c determines whether the voltage of the power line L1 is stable or not. The process in step S106 is the same as the process in step S103 described above. If it is determined that the voltage of the power line L1 is unstable (step S106 / NO), the process returns to step S102. On the other hand, if it is determined that the voltage of the power line L1 is stable (step S106 / YES), the process proceeds to step S107. In step S107, the diagnostic unit 52c diagnoses that the power line L1 is abnormal, and the control flow shown in Figure 5 ends. If it is determined that the power line L1 is abnormal, for example, the notification device 6 notifies the LiDAR that the power line L1 is abnormal. 【0049】 The details of power line diagnosis will be explained below with reference to Figures 6 to 8. Specifically, the first example of power line diagnosis will be explained with reference to Figures 6 and 7, and then the second example of power line diagnosis will be explained with reference to Figure 8. 【0050】 The diagnostic unit 52c changes the current (specifically, the current value) applied to the suction valve 31 during power line diagnosis. The diagnostic unit 52c then diagnoses an abnormality in the power line L1 based on the voltage change, which is the change in the voltage of the power line L1 at that time. Specifically, in power line diagnosis, the diagnostic unit 52c applies current to the suction valve 31 of the rear wheel braking mechanism 14. The following mainly describes an example in which current is applied to the suction valve 31 of the rear wheel braking mechanism 14 during power line diagnosis, but the solenoid valve to which current is applied during power line diagnosis may be, for example, the suction valve 31 of the front wheel braking mechanism 12, or the release valve 32 of the front wheel braking mechanism 12 or the rear wheel braking mechanism 14. 【0051】 Figure 6 is a graph showing an example of the changes in various state variables in the first example of power line diagnosis. In Figure 6, the horizontal axis is time t, and the changes in various state variables are shown. In Figure 6, the state variables shown are the voltage V of the power line L1 (specifically, the voltage detected by the voltage sensor 43) and the current value C of the current applied to the suction valve 31. 【0052】 As shown in Figure 6, in the first example of power line diagnosis, the diagnostic unit 52c changes the current (specifically, current value C) applied to the suction valve 31 so that the open / closed state of the suction valve 31 switches between the open and closed states. Specifically, the diagnostic unit 52c causes the current (specifically, current value C) to transition in a rectangular wave shape. In the example in Figure 6, the diagnostic unit 52c sequentially generates four rectangular wave pulse currents P1, P2, P3, and P4, in which the current value C transitions in the order of minimum value Cmin, maximum value Cmax, and minimum value Cmin. Note that the number of pulse currents generated may be other than four. The minimum value Cmin is 0A. That is, when the current value C is the minimum value Cmin, no current is applied to the suction valve 31, and the suction valve 31 is in the open state. When the current value C is the maximum value Cmax, the suction valve 31 is in the closed state. 【0053】 In the example in Figure 6, before time t1, the current value C is at its minimum value Cmin. Between time t1 and time t2, the current value C is at its maximum value Cmax. Between time t2 and time t3, the current value C is at its minimum value Cmin. Between time t3 and time t4, the current value C is at its maximum value Cmax. Between time t4 and time t5, the current value C is at its minimum value Cmin. Between time t5 and time t6, the current value C is at its maximum value Cmax. Between time t6 and time t7, the current value C is at its minimum value Cmin. Between time t7 and time t8, the current value C is at its maximum value Cmax. After time t8, the current value C is at its minimum value Cmin. 【0054】 In other words, in the example in Figure 6, before time t1, the sealing valve 31 is in the open state. Between time t1 and time t2, the sealing valve 31 is in the closed state. Between time t2 and time t3, the sealing valve 31 is in the open state. Between time t3 and time t4, the sealing valve 31 is in the closed state. Between time t4 and time t5, the sealing valve 31 is in the open state. Between time t5 and time t6, the sealing valve 31 is in the closed state. Between time t6 and time t7, the sealing valve 31 is in the open state. Between time t7 and time t8, the sealing valve 31 is in the closed state. After time t8, the sealing valve 31 is in the open state. 【0055】 As described above, in the example in Figure 6, the valve 31 switches to the closed state four times due to the sequential generation of four rectangular wave pulse currents P1, P2, P3, and P4. In the example in Figure 6, the duration of the closed state of the valve 31 is the same in all instances when the valve 31 switches to the closed state. That is, the pulse widths of the four rectangular wave pulse currents P1, P2, P3, and P4 are the same. However, as will be described later, the duration of the closed state of the valve 31 may differ in some instances when the valve 31 switches to the closed state from other instances. 【0056】 When the current value C is at its minimum value Cmin and no current is applied to the valve 31, there is no voltage drop due to the resistance of the power line L1. Therefore, the voltage V across the power line L1 detected by the voltage sensor 43 is approximately equal to the voltage of the power supply B1. On the other hand, when the current value C is at its maximum value Cmax and current is applied to the valve 31, a voltage drop occurs due to the resistance of the power line L1. Therefore, when the current value C is at its maximum value Cmax, the voltage V across the power line L1 detected by the voltage sensor 43 is lower than when the current value C is at its minimum value Cmin. Therefore, in the example in Figure 6, the voltage V across the power line L1 is lower between time points t1 and t2, t3 and t4, t5 and t6, and t7 and t8 compared to other time points. 【0057】 In the first example of power line diagnosis, the diagnostic unit 52c performs a power line diagnosis based on the voltage change in the power line L1 when the current applied to the suction valve 31 (specifically, the current value C) changes as the suction valve 31 switches between an open state and a closed state. Specifically, the diagnostic unit 52c performs a power line diagnosis based on the amount of voltage change in the power line L1 before and after the suction valve 31 switches between an open state and a closed state. The amount of voltage change in the power line L1 before and after the suction valve 31 switches between an open state and a closed state (for example, the difference between the voltage V before time point t1 and the voltage V between time point t1 and time point t2) corresponds to the voltage drop due to the resistance of the power line L1. Therefore, the diagnostic unit 52c can evaluate the resistance of the power line L1 based on such a voltage change. Then, the diagnostic unit 52c diagnoses an abnormality in the power line L1 based on the evaluation result of the resistance of the power line L1. 【0058】 In Figure 6, the timing of acquiring the voltage V to determine the voltage change amount of the power line L1 is indicated by dots (e.g., dots D1, D2, D3, D4). The difference between two voltages V acquired at the timings indicated by the paired dots in Figure 6, which are each indicated by a dashed line, is acquired as the voltage change amount. In the example in Figure 6, the diagnostic unit 52c acquires the voltage change amount of the power line L1 before and after the loading valve 31 switches between the open and closed states in response to the generation of a pulse current. 【0059】 For example, in the example shown in Figure 6, the diagnostic unit 52c acquires the difference between the voltage V acquired at the acquisition timing of dot D1 before time t1 and the voltage V acquired at the acquisition timing of dot D2 between time t1 and time t2 as the voltage change amount. This voltage change amount corresponds to the voltage change amount of the power line L1 before and after the loading valve 31 switches from the open state to the closed state due to the generation of pulse current P1. 【0060】 Next, the diagnostic unit 52c acquires the difference between the voltage V acquired at the acquisition timing of dot D3 between time point t1 and time point t2, and the voltage V acquired at the acquisition timing of dot D4 between time point t2 and time point t3, as the voltage change amount. This voltage change amount corresponds to the voltage change amount of the power supply line L1 before and after the loading valve 31 switches from the closed state to the open state due to the generation of pulse current P1. 【0061】 Similarly, for pulse currents P2, P3, and P4, the diagnostic unit 52c acquires the voltage change across the power line L1 before and after the valve 31 switches from the open state to the closed state, and the voltage change across the power line L1 before and after the valve 31 switches from the closed state to the open state. In this way, the diagnostic unit 52c acquires two dashed lines and two corresponding voltage changes for each pulse current. As a result, the diagnostic unit 52c uses the four pulse currents P1, P2, P3, and P4 to acquire eight dashed lines and eight corresponding voltage changes. 【0062】 The diagnostic unit 52c evaluates the resistance of the power line L1 for each acquired voltage change. In the example in Figure 6, the diagnostic unit 52c evaluates the resistance of the power line L1 for each of the eight voltage changes. In other words, the diagnostic unit 52c performs eight different evaluations of the resistance of the power line L1. In the resistance evaluation, the diagnostic unit 52c evaluates the resistance as normal if the voltage change is smaller than the reference change (i.e., the reference resistance value replaced by the voltage change). If the number of resistance values ​​evaluated as normal among the eight evaluations is equal to or greater than the reference number, the diagnostic unit 52c diagnoses the power line L1 as normal and terminates the power line diagnosis. The reference number is a number smaller than the total number of resistance evaluations (eight in the example above) and can be any number. 【0063】 Furthermore, if the number of resistance values ​​evaluated as normal among the eight resistance value evaluations is less than the standard number, the diagnostic unit 52c may diagnose that the power line L1 is abnormal. Alternatively, in this case, the diagnostic unit 52c does not have to immediately diagnose that the power line L1 is abnormal. For example, the diagnostic unit 52c may repeat the evaluation set described above, which generates multiple (four in the above example) pulse currents P1, P2, P3, and P4 and evaluates multiple (eight in the above example) resistance values. If the number of resistance values ​​evaluated as normal in the second evaluation set is equal to or greater than the standard number, the diagnostic unit 52c may diagnose that the power line L1 is normal and terminate the power line diagnosis. In this case, if, for example, the diagnostic unit 52c performs the evaluation set up to the maximum number of times (e.g., three times) and does not diagnose that the power line L1 is normal in any of the evaluation sets, it will diagnose that the power line L1 is abnormal and terminate the power line diagnosis. 【0064】 In the example above, as explained with reference to Figure 5, a power line diagnosis is performed when it is determined that the voltage V of the power line L1 is stable. This improves the reliability of the power line diagnosis. However, the diagnostic unit 52c may perform a power line diagnosis regardless of whether it is determined that the voltage V of the power line L1 is stable or not. In this case, if the duration of the closed state of the suction valve 31 is the same in all instances when the suction valve 31 switches to the closed state (i.e., the pulse widths of the multiple rectangular wave pulse currents are the same), the reliability of the power line diagnosis is likely to decrease due to noise from other signals in the vehicle 100. Therefore, from the viewpoint of improving the reliability of the power line diagnosis, in this case, it is preferable that the duration of the closed state of the suction valve 31 differs in some instances when the suction valve 31 switches to the closed state from some instances. In other words, it is preferable that the pulse widths of some of the multiple rectangular wave pulse currents differ from the pulse widths of some instances. 【0065】 In the example above, we described a case where the current value C progresses in the order of minimum value Cmin, maximum value Cmax, and then minimum value Cmin for each pulse current. However, for each pulse current, the current value C only needs to progress in the order of the current value at which the suction valve 31 is open, the current value at which the suction valve 31 is closed, and the current value at which the suction valve 31 is open, and the value that the current value C can take is not limited to the example above. For example, the current value C between time point t1 and time point t2, between time point t3 and time point t4, between time point t5 and time point t6, and between time point t7 and time point t8 may be a value smaller than the maximum value Cmax. Also, for example, the current value C between time point t2 and time point t3, between time point t4 and time point t5, and between time point t6 and time point t7 may be a value larger than the minimum value Cmin. 【0066】 Figure 7 is a graph showing an example of the changes in various state variables in a comparative example with the first example of power line diagnosis. In Figure 7, as in Figure 6, the horizontal axis is time t, and the changes in the voltage V of the power line L1 and the current value C of the current applied to the suction valve 31 are shown as the changes in various state variables. 【0067】 The comparative example shown in Figure 7 is an example of power line diagnosis in a vehicle other than a saddle-type vehicle, unlike vehicle 100. In the power line diagnosis in Figure 6 described above, the open / closed state of the containment valve 31 switches instantaneously between the open and closed states. As a result, the operating sound of the containment valve 31 becomes somewhat louder. However, vehicle 100 is a saddle-type vehicle, and ambient noise reaches the rider of a saddle-type vehicle directly. Therefore, the operating sound of the containment valve 31 is less likely to be perceived as noise by the rider of a saddle-type vehicle. The fact that the rider of a saddle-type vehicle may be wearing a helmet is also a factor that makes the operating sound of the containment valve 31 less likely to be perceived as noise. On the other hand, in vehicles other than saddle-type vehicles, the operating sound of the containment valve 31 is more likely to be perceived as noise, and quietness inside the vehicle is required. 【0068】 Therefore, in the comparative example, the diagnostic unit 52c first gradually increases the current value C from the minimum value Cmin to the intermediate value Cmid. In the example in Figure 7, before time t11, the current value C has gradually increased from the minimum value Cmin to the intermediate value Cmid. Here, although the intermediate value Cmid is smaller than the maximum value Cmax, when the current value C is at the intermediate value Cmid, the suction valve 31 is closed. Thus, before time t11, the suction valve 31 is closed over a certain period of time. 【0069】 In the comparative example, the diagnostic unit 52c changes the current value C so that the filling valve 31 remains closed. In the example shown in Figure 7, the diagnostic unit 52c sequentially generates four rectangular wave pulse currents P11, P12, P13, and P14, in which the current value C transitions from an intermediate value Cmid to a maximum value Cmax and then back to an intermediate value Cmid. 【0070】 In the example in Figure 7, the current value C is at its midpoint Cmid between time t11 and time t12. The current value C is at its maximum value Cmax between time t12 and time t13. The current value C is at its midpoint Cmid between time t13 and time t14. The current value C is at its maximum value Cmax between time t14 and time t15. The current value C is at its midpoint Cmid between time t15 and time t16. The current value C is at its maximum value Cmax between time t16 and time t17. The current value C is at its midpoint Cmid between time t17 and time t18. The current value C is at its maximum value Cmax between time t18 and time t19. The current value C is at its midpoint Cmid between time t19 and time t20. 【0071】 As described above, the suction valve 31 is closed in both cases: when the current value C is the intermediate value Cmid, and when the current value C is the maximum value Cmax. Therefore, the suction valve 31 is kept closed while the four rectangular wave pulse currents P11, P12, P13, and P14 are generated. The diagnostic unit 52c acquires the difference between two voltages V, which are acquired at the timings indicated by the two dots paired by the dashed line in Figure 7, as the voltage change, similar to the example in Figure 6. Then, the diagnostic unit 52c evaluates the resistance value of the power line L1 for each of the eight voltage change values ​​acquired using the four pulse currents P11, P12, P13, and P14, similar to the example in Figure 6. 【0072】 After time t20, the diagnostic unit 52c gradually decreases the current value C from the intermediate value Cmid to the minimum value Cmin. Therefore, after time t20, the filling valve 31 opens over a certain period of time. 【0073】 As described above, in the comparative example shown in Figure 7, at the start of the power line diagnosis, the current value C gradually increases from the minimum value Cmin to the intermediate value Cmid, and at the end of the power line diagnosis, the current value C gradually decreases from the intermediate value Cmid to the minimum value Cmin. As a result, at the start of the power line diagnosis, the suction valve 31 changes from the open state to the closed state over a certain period of time, and at the end of the power line diagnosis, the suction valve 31 changes from the closed state to the open state over a certain period of time. Therefore, the operating noise of the suction valve 31 can be reduced, ensuring quietness inside the vehicle. 【0074】 As explained above, in the first example of power line diagnosis, the diagnostic unit 52c performs power line diagnosis based on the voltage change in power line L1 when the current applied to the suction valve 31 (specifically, the current value C) changes as the suction valve 31 switches between the open and closed states. This reduces the time required to change the current applied to the suction valve 31 at the start and end of the power line diagnosis, thus shortening the time required for power line diagnosis. Therefore, abnormalities in power line L1 can be appropriately diagnosed. 【0075】 Furthermore, in the first example of power line diagnosis, the suction valve 31 switches between open and closed states even while multiple pulse currents are being generated. Therefore, it is possible to create a state in which the suction valve 31 is open while multiple pulse currents are being generated. For example, in the example in Figure 6, while four rectangular wave pulse currents P1, P2, P3, and P4 are being generated, the suction valve 31 is open between time points t2 to t3, between time points t4 to t5, and between time points t6 to t7. 【0076】 In the brake system 10, as described above, there is one wheel cylinder 24 that communicates with one master cylinder 21. Also, as described above, in the power line diagnosis, specifically, current is applied to the suction valve 31 of the rear wheel braking mechanism 14. Therefore, if the suction valve 31 of the rear wheel braking mechanism 14 is closed during the power line diagnosis, the hydraulic pressure of the brake fluid in the wheel cylinder 24 of the rear wheel 4 cannot be increased by the rider's braking operation. On the other hand, in the first example of the power line diagnosis, a state in which the suction valve 31 is open can be created while multiple pulse currents are being generated, so the situation in which the hydraulic pressure of the brake fluid in the wheel cylinder 24 of the rear wheel 4 cannot be increased by the rider's braking operation is suppressed. 【0077】 Figure 8 is a graph showing an example of the changes in various state variables in the second example of power line diagnosis. In Figure 8, as with Figures 6 and 7, the horizontal axis is time t, and the changes in the voltage V of the power line L1 and the current value C of the current applied to the suction valve 31 are shown as changes in various state variables. 【0078】 As shown in Figure 8, in the second example of power line diagnosis, the diagnostic unit 52c generates a single rectangular wave pulse current P in which the current value C of the current applied to the suction valve 31 transitions in the order of a first current value C1, a second current value C2 greater than the first current value C1, and a third current value C3 less than the second current value C2. In the example in Figure 8, the first current value C1 and the third current value C3 are the minimum value Cmin, and the second current value C2 is the maximum value Cmax. In other words, in the example in Figure 8, the diagnostic unit 52c generates a single rectangular wave pulse current P in which the current value C transitions in the order of minimum value Cmin, maximum value Cmax, and minimum value Cmin. However, as will be described later, the values ​​of the first current value C1, the second current value C2, and the third current value C3 are not limited to this example. Also, the first current value C1 and the third current value C3 may be different from each other. 【0079】 In the example in Figure 8, the current value C is at its minimum value Cmin before time t21. Between time t21 and time t22, the current value C is at its maximum value Cmax. After time t22, the current value C is at its minimum value Cmin. In other words, in the example in Figure 8, the suction valve 31 is in the open state before time t21. Between time t21 and time t22, the suction valve 31 is in the closed state. After time t22, the suction valve 31 is in the open state. 【0080】 In the example in Figure 8, the voltage V across power line L1 is lower between time point t21 and time point t22 due to the voltage drop caused by the resistance of power line L1 compared to other time points. The voltage V across power line L1 acquired when the current value C is the first current value C1 is called the first voltage V1. In other words, the first voltage V1 is the voltage V acquired before time point t21. The voltage V across power line L1 acquired when the current value C is the second current value C2 is called the second voltage V2. In other words, the second voltage V2 is the voltage V acquired between time point t21 and time point t22. The voltage V across power line L1 acquired when the current value C is the third current value C3 is called the third voltage V3. In other words, the third voltage V3 is the voltage V acquired after time point t22. 【0081】 In the second example of power line diagnosis, the diagnostic unit 52c performs a power line diagnosis based on the voltage change of the power line L1 before and after the current value C switches in the pulse current P. Specifically, the diagnostic unit 52c performs a first resistance value evaluation to evaluate the resistance value of the power line L1 based on the voltage change of the power line L1 before and after the current value C transitions from a first current value C1 (minimum value Cmin in the example of Figure 8) to a second current value C2 (maximum value Cmax in the example of Figure 8) in the pulse current P. The diagnostic unit 52c also performs a second resistance value evaluation to evaluate the resistance value of the power line L1 based on the voltage change before and after the current value C transitions from a second current value C2 (maximum value Cmax in the example of Figure 8) to a third current value C3 (minimum value Cmin in the example of Figure 8) in the pulse current P. Then, the diagnostic unit 52c diagnoses an abnormality in the power line L1 based on the results of the first and second resistance value evaluations. 【0082】 In Figure 8, as in Figure 6, the timing of acquiring the voltage V to determine the voltage change amount of the power line L1 is indicated by dots (e.g., dots D11, D12, etc.). The difference between the two voltages V acquired at the timings indicated by the two dots paired by a dashed line in Figure 8 is acquired as the voltage change amount. 【0083】 Note that in Figure 8, for ease of understanding, some of the dashed lines indicating paired dots have been omitted. Also, while Figure 8 shows an example where there are six dots indicating the acquisition timing of the first voltage V1 (dots D11-D16), four dots indicating the acquisition timing of the second voltage V2 (dots D21-D24), and six dots indicating the acquisition timing of the third voltage V3 (dots D31-D36), the number and arrangement of the dots are not limited to the example in Figure 8, as will be discussed later. 【0084】 The diagnostic unit 52c acquires the voltage change amount based on the first voltage V1 and the second voltage V2 during the first resistance value evaluation. For example, in the example in Figure 8, the diagnostic unit 52c acquires the first voltage V1 at the acquisition timings of dots D11, D12, D13, D14, D15, and D16 before time t21. The diagnostic unit 52c also acquires the second voltage V2 at the acquisition timings of dots D21, D22, D23, and D24 between time t21 and time t22. 【0085】 The diagnostic unit 52c then acquires the difference between the first voltage V1 acquired at the acquisition timing of dot D11 and the second voltage V2 acquired at the acquisition timings of dots D21, D22, D23, and D24, respectively, as the voltage change amount. In other words, the diagnostic unit 52c acquires four voltage change amounts for the first voltage V1 acquired at the acquisition timing of dot D11. Similarly, it acquires four voltage change amounts for the first voltage V1 acquired at the acquisition timings of dots D12, D13, D14, D15, and D16. As a result, the diagnostic unit 52c acquires a total of 24 voltage change amounts. 【0086】 The diagnostic unit 52c evaluates the resistance of the power line L1 for each of the 24 voltage change values ​​obtained in the first resistance evaluation. In other words, the first resistance evaluation performs 24 different evaluations of the resistance of the power line L1. In each evaluation of the first resistance evaluation, as in the first example of power line diagnosis described above, the resistance is evaluated as normal if the voltage change is smaller than the reference change. 【0087】 In the second resistance value evaluation, the diagnostic unit 52c acquires the voltage change amount based on the second voltage V2 and the third voltage V3. For example, in the example in Figure 8, in addition to the second voltage V2 acquired in the first resistance value evaluation, the diagnostic unit 52c acquires the third voltage V3 at acquisition timings D31, D32, D33, D34, D35, and D36 after time t22. 【0088】 The diagnostic unit 52c then acquires the difference between the third voltage V3 acquired at the acquisition timing of dot D31 and the second voltage V2 acquired at the acquisition timings of dots D21, D22, D23, and D24, as the voltage change amount. In other words, the diagnostic unit 52c acquires four voltage change amounts for the third voltage V3 acquired at the acquisition timing of dot D31. Similarly, it acquires four voltage change amounts for the third voltage V3 acquired at the acquisition timings of dots D32, D33, D34, D35, and D36. As a result, the diagnostic unit 52c acquires a total of 24 voltage change amounts. 【0089】 The diagnostic unit 52c evaluates the resistance of power line L1 for each of the 24 voltage change values ​​obtained in the second resistance evaluation. In other words, the second resistance evaluation performs 24 different evaluations of the resistance of power line L1. In each evaluation of the second resistance evaluation, as in the first example of power line diagnosis described above, the resistance is evaluated as normal if the voltage change is smaller than the reference change. 【0090】 If the number of resistance values ​​evaluated as normal among the total of 48 resistance values ​​evaluated through the first resistance value evaluation and the second resistance value evaluation is equal to or greater than a certain threshold, the diagnostic unit 52c diagnoses that the power line L1 is normal and terminates the power line diagnosis. 【0091】 Furthermore, if the number of resistance values ​​evaluated as normal among the total of 48 resistance values ​​evaluated is less than the standard number, the diagnostic unit 52c may diagnose that the power line L1 is abnormal. Alternatively, in this case, the diagnostic unit 52c does not have to immediately diagnose that the power line L1 is abnormal. For example, the diagnostic unit 52c may generate one pulse current P and repeat the evaluation set described above, which evaluates multiple resistance values ​​(a total of 48 in the above example). If the number of resistance values ​​evaluated as normal in the second evaluation set is equal to or greater than the standard number, the diagnostic unit 52c may diagnose that the power line L1 is normal and terminate the power line diagnosis. In this case, if, for example, the diagnostic unit 52c has performed the evaluation set up to the maximum number of times (e.g., 3 times) and has not diagnosed that the power line L1 is normal in any of the evaluation sets, it will diagnose that the power line L1 is abnormal and terminate the power line diagnosis. 【0092】 As explained above, in the second example of power line diagnosis, the diagnostic unit 52c performs a first resistance value evaluation to evaluate the resistance value of the power line L1 based on the amount of voltage change of the power line L1 before and after the current value C transitions from a first current value C1 (minimum value Cmin in the example of Figure 8) to a second current value C2 (maximum value Cmax in the example of Figure 8) in the pulse current P. The diagnostic unit 52c also performs a second resistance value evaluation to evaluate the resistance value of the power line L1 based on the amount of voltage change before and after the current value C transitions from a second current value C2 (maximum value Cmax in the example of Figure 8) to a third current value C3 (minimum value Cmin in the example of Figure 8) in the pulse current P. Then, the diagnostic unit 52c diagnoses an abnormality in the power line L1 based on the results of the first and second resistance value evaluations. Furthermore, in the first and second resistance value evaluations, multiple voltage change amounts are obtained where at least one of the start and end points of the voltage change is different from each other, and multiple resistance value evaluations are performed. This allows for the evaluation of multiple resistance values ​​using a single pulse current P. Therefore, it becomes unnecessary to generate multiple pulse currents P during power line diagnosis, thus shortening the time required for power line diagnosis. Consequently, abnormalities in power line L1 can be properly diagnosed. 【0093】 The above describes an example in which, in both the first and second resistance evaluations, multiple voltage change values ​​are obtained where at least one of the start and end points of the voltage change is different from each other, and multiple resistance evaluations are performed. However, the same effect as above is achieved if, in at least one of the first and second resistance evaluations, multiple voltage change values ​​are obtained where at least one of the start and end points of the voltage change is different from each other, and multiple resistance evaluations are performed. For example, if multiple resistance evaluations are performed in the first resistance evaluation, only one resistance evaluation may be performed in the second resistance evaluation. Also, if multiple resistance evaluations are performed in the second resistance evaluation, only one resistance evaluation may be performed in the first resistance evaluation. 【0094】 As described above, the number and arrangement of dots indicating the timing of voltage V acquisition for identifying the voltage change amount are not limited to the example in Figure 8. However, it is preferable that the following improvements shown in Figure 8 are made to the timing of voltage V acquisition. 【0095】 For example, as a first improvement to the timing of acquiring voltage V, it is preferable that the acquisition timing of the second voltage V2 is biased towards the latter half of the period during which the current value C in the pulse current P is the second current value C2, rather than the first half. In the example in Figure 8, dots D21, D22, D23, and D24 are biased towards the latter half of the period from time t21 to time t22, during which the current value C in the pulse current P is the second current value C2, rather than the first half. For example, a bias in the acquisition timing towards the latter half of a period may mean that the average value of multiple acquisition timings belongs to the latter half of that period. Also, for example, a bias in the acquisition timing towards the latter half of a period may mean that the number of acquisition timings belonging to the latter half of a period is greater than the number belonging to the first half of that period. 【0096】 Immediately after the transition timing from the first current value C1 to the second current value C2 (time t21 in the example in Figure 8), the voltage V has not yet fully dropped. Therefore, by shifting the timing of acquiring the second voltage V2 to the latter half of the period when the current value C is the second current value C2, the acquisition of the voltage V while it is still dropping as the second voltage V2 is suppressed. This improves the reliability of the first and second resistance value evaluations. 【0097】 Furthermore, as a second improvement to the timing of acquiring voltage V, it is preferable that the timing of acquiring the third voltage V3 is at a time that is at least a reference time after the transition timing from the second current value C2 to the third current value C3. In the example in Figure 8, the timing of acquiring the third voltage V3, indicated by dot D31, which shows the earliest acquisition timing among dots D31, D32, D33, D34, D35, and D36, is at a time that is at least a reference time after time t22, which is the transition timing from the second current value C2 to the third current value C3. Immediately after the transition timing from the second current value C2 to the third current value C3 (time t22 in the example in Figure 8), the rise in voltage V has not yet been completed. The reference time is set to a time that is longer than the time it takes for the rise in voltage V accompanying the transition from the second current value C2 to the third current value C3 to be completed. This suppresses the acquisition of the rising voltage V as the third voltage V3. Therefore, the reliability of the second resistance value evaluation is improved. 【0098】 Furthermore, as a third improvement to the timing of acquiring voltage V, for example, it is preferable that the time interval for acquiring the second voltage V2 is shorter than the time intervals for acquiring the first voltage V1 and the third voltage V3. In the example in Figure 8, the time intervals of dots D11, D12, D13, D14, D15, and D16 are approximately the same as the time intervals of dots D31, D32, D33, D34, D35, and D36. On the other hand, the time intervals of dots D21, D22, D23, and D24 are shorter than the time intervals of dots D11, D12, D13, D14, D15, and D16, and the time intervals of dots D31, D32, D33, D34, D35, and D36. This makes it possible to shorten the period during which the current value C in the pulse current P is at the second current value C2 (the maximum value Cmax in the example in Figure 8) (the period from time t21 to time t22 in the example in Figure 8). Therefore, the period during which the sealing valve 31 is closed can be shortened. As a result, situations in which the hydraulic pressure of the brake fluid in the wheel cylinder 24 of the rear wheel 4 cannot be increased by the rider's braking operation are suppressed. 【0099】 Furthermore, as a fourth improvement to the timing of acquiring voltage V, it is preferable that the number of acquisition timings for the second voltage V2 is smaller than the number of acquisition timings for the first voltage V1 and the third voltage V3, respectively. In the example in Figure 8, the number of dots D11, D12, D13, D14, D15, and D16 is the same as the number of dots D31, D32, D33, D34, D35, and D36, both being 6. On the other hand, the number of dots D21, D22, D23, and D24 is 4, which is fewer than the number of dots D11, D12, D13, D14, D15, and D16, and the number of dots D31, D32, D33, D34, D35, and D36. This makes it possible to shorten the period during which the current value C in the pulse current P is at the second current value C2 (the maximum value Cmax in the example in Figure 8) (the period from time t21 to time t22 in the example in Figure 8). Therefore, the period during which the sealing valve 31 is closed can be shortened. As a result, situations in which the hydraulic pressure of the brake fluid in the wheel cylinder 24 of the rear wheel 4 cannot be increased by the rider's braking operation are suppressed. 【0100】 Furthermore, it is not necessary to employ any one of the four types of techniques described above regarding the timing of acquiring voltage V: the first, second, third, and fourth techniques. Any combination of multiple techniques may be adopted. 【0101】 The above example illustrates a case where the weights of multiple resistance value evaluations are the same. However, the diagnostic unit 52c may make some of the weights of the multiple resistance value evaluations different from the weights of some of the other evaluations. 【0102】 For example, as a first improvement to the evaluation weights, the diagnostic unit 52c may give more weight to the evaluation of resistance values ​​using the second voltage V2 with a later acquisition timing compared to the evaluation of resistance values ​​using the second voltage V2 with an earlier acquisition timing. For example, the weight of the evaluation of resistance values ​​using the second voltage V2 corresponding to dots D23 and D24, which are acquired later than dots D21 and D22, may be given more weight compared to the evaluation of resistance values ​​using the second voltage V2 corresponding to dots D21 and D22, which are acquired earlier than dots D23 and D24. Alternatively, for example, the weights may be increased in the order of evaluation of resistance values ​​using the second voltage V2 corresponding to dot D21, evaluation of resistance values ​​using the second voltage V2 corresponding to D22, evaluation of resistance values ​​using the second voltage V2 corresponding to D23, and evaluation of resistance values ​​using the second voltage V2 corresponding to D24. 【0103】 As described above, immediately after the transition timing from the first current value C1 to the second current value C2 (time t21 in the example in Figure 8), the voltage V has not yet fully dropped. Therefore, the second voltage V2, which is acquired later, is less likely to be a voltage V that is still dropping compared to the second voltage V2, which is acquired earlier. Thus, by giving more weight to the evaluation of resistance using the second voltage V2 acquired later compared to the evaluation of resistance using the second voltage V2 acquired earlier, the reliability of the first and second resistance value evaluations is improved. 【0104】 Furthermore, as a second improvement to the evaluation weighting, the diagnostic unit 52c may give a heavier weight to the evaluation of resistance values ​​using the third voltage V3 with a later acquisition timing compared to the evaluation of resistance values ​​using the third voltage V3 with an earlier acquisition timing. For example, the weight of the evaluation of resistance values ​​using the third voltage V3 corresponding to dots D31, D32, and D36, which are acquired earlier than dots D34, D35, and D36, may be given a heavier weight to the evaluation of resistance values ​​using the third voltage V3 corresponding to dots D34, D35, and D36, which are acquired later than dots D31, D32, and D33. Alternatively, for example, the weighting may be increased in the following order: evaluation of resistance using the third voltage V3 corresponding to dot D31, evaluation of resistance using the third voltage V3 corresponding to dot D32, evaluation of resistance using the third voltage V3 corresponding to dot D33, evaluation of resistance using the third voltage V3 corresponding to dot D34, evaluation of resistance using the third voltage V3 corresponding to dot D35, and evaluation of resistance using the third voltage V3 corresponding to dot D36. 【0105】 As described above, immediately after the transition timing from the second current value C2 to the third current value C3 (time t22 in the example in Figure 8), the rise in voltage V has not yet been completed. Therefore, the third voltage V3, which is acquired later, is less likely to be a rising voltage V compared to the third voltage V3, which is acquired earlier. Thus, by giving more weight to the evaluation of resistance using the third voltage V3, which is acquired earlier, compared to the evaluation of resistance using the third voltage V3, the reliability of the second resistance value evaluation is improved. 【0106】 Furthermore, it is not necessary to adopt either of the two types of weighting improvements described above, the first and second improvements, or to adopt a combination of both improvements. 【0107】 In the above example, we described a case where, in the pulse current P, the first current value C1 and the third current value C3 are at their minimum value Cmin, and the second current value C2 is at its maximum value Cmax. However, the values ​​of the first current value C1, the second current value C2, and the third current value C3 are not limited to this example. For example, the second current value C2 may be smaller than the maximum value Cmax. Also, in the above example, the open / closed state of the suction valve 31 switches between the open state and the closed state in response to the generation of the pulse current P. However, the open / closed state of the suction valve 31 does not have to switch between the open state and the closed state in response to the generation of the pulse current P. For example, the first current value C1 and the third current value C3 may be the intermediate value Cmid in Figure 7. In this case, the suction valve 31 is maintained in the closed state not only when the current value C is the second current value C2, but also when the current value C is the first current value C1 or the third current value C3. 【0108】 The above example describes a vehicle 100 that is a saddle-type vehicle. However, the second example of power line diagnosis, as shown in Figure 8, can also be applied to other vehicles (e.g., four-wheeled vehicles) besides saddle-type vehicles. 【0109】 <Effects of the hydraulic control unit> The effects of the hydraulic control unit 5 according to an embodiment of the present invention will be described. 【0110】 First, let's explain the effects of the first example of power line diagnostics. 【0111】 In the hydraulic control unit 5, the control device 52 includes a diagnostic unit 52c that performs a power line diagnosis based on the voltage change in the power line L1 when the current applied to the suction valve 31 is changed. The diagnostic unit 52c performs the power line diagnosis based on the voltage change in the power line L1 when the current applied to the suction valve 31 changes as the suction valve 31 switches between an open state and a closed state. This reduces the time required to change the current applied to the suction valve 31 at the start and end of the power line diagnosis, thus shortening the time required for the power line diagnosis. Therefore, abnormalities in the power line L1 can be appropriately diagnosed. 【0112】 Preferably, in the hydraulic control unit 5, the diagnostic unit 52c causes the current applied to the suction valve 31 to change in a rectangular wave shape during power line diagnosis. This appropriately switches the open / closed state of the suction valve 31 between the open state and the closed state in accordance with the generation of a rectangular wave pulse current. Therefore, power line diagnosis is appropriately performed based on the voltage change of the power line L1 when the current applied to the suction valve 31 changes in accordance with the switching between the open and closed states of the suction valve 31. 【0113】 Preferably, in the hydraulic control unit 5, the diagnostic unit 52c performs a power line diagnosis when it is determined that the voltage V of the power line L1 is stable. This improves the reliability of the power line diagnosis. 【0114】 Preferably, in the hydraulic control unit 5, during power line diagnosis, the suction valve 31 switches to the closed state multiple times, and the duration of the closed state of the suction valve 31 is the same each time. This makes it possible to minimize the duration of the closed state of the suction valve 31 each time. Therefore, situations in which the hydraulic pressure of the brake fluid in the wheel cylinder 24 cannot be increased by the rider's braking operation are suppressed. 【0115】 Preferably, in the hydraulic control unit 5, during power line diagnosis, the suction valve 31 switches to the closed state multiple times, and the duration of the closed state of the suction valve 31 differs in some instances from in others. This improves the reliability of power line diagnosis while omitting the determination of whether or not the voltage V of the power line L1 is stable. 【0116】 Preferably, in the hydraulic control unit 5, the diagnostic unit 52c performs a power line diagnosis based on the voltage change of the power line L1 before and after the suction valve 31 switches between the open and closed states. This appropriately realizes that the power line diagnosis is performed based on the voltage change of the power line L1 when the current applied to the suction valve 31 changes with the switching of the suction valve 31 between the open and closed states. 【0117】 Preferably, in the hydraulic control unit 5, the diagnostic unit 52c performs a power line diagnosis based on the voltage change before and after the suction valve 31 switches from an open state to a closed state, and the voltage change before and after the suction valve 31 switches from a closed state to an open state. This allows for evaluation of at least two resistance values ​​of the power line L1 for a single pulse current. Therefore, the number of pulse currents generated in the power line diagnosis can be reduced, and the time required for the power line diagnosis can be shortened. However, the diagnostic unit 52c may perform a power line diagnosis for at least one pulse current without relying on either the voltage change before and after the suction valve 31 switches from an open state to a closed state, or the voltage change before and after the suction valve 31 switches from a closed state to an open state. 【0118】 Preferably, the brake system 10 includes a hydraulic control unit 5, and in the brake system 10, there is one wheel cylinder 24 communicating with one master cylinder 21. In the first example of power line diagnosis, the suction valve 31 switches between open and closed states even while multiple pulse currents are being generated. Therefore, it is possible to create a state in which the suction valve 31 is open while multiple pulse currents are being generated. Thus, in power line diagnosis, the situation in which the hydraulic pressure of the brake fluid in the wheel cylinder 24 of the braking mechanism (rear wheel braking mechanism 14 in the above example) to which the suction valve 31 to which current is applied belongs cannot be increased by the rider's braking operation is suppressed. 【0119】 Next, we will explain the effects of a second example of power line diagnostics. 【0120】 In the hydraulic control unit 5, the control device 52 includes a diagnostic unit 52c that performs a power line diagnosis to diagnose abnormalities in the power line L1 based on the voltage change in the power line L1 when the current applied to the solenoid valve (in the above example, the suction valve 31) from the power supply B1 via the power line L1 is changed. In the power line diagnosis, the diagnostic unit 52c generates a single rectangular wave-shaped pulse current P in which the current value C of the current applied to the solenoid valve changes in the order of a first current value C1, a second current value C2 which is greater than the first current value C1, and a third current value C3 which is less than the second current value C2. A first resistance evaluation is performed to assess the resistance of power line L1 based on the voltage change of power line L1 before and after the transition to value C2. A second resistance evaluation is performed to assess the resistance of power line L1 based on the voltage change of power line L1 before and after the transition of current value C from the second current value C2 to the third current value C3 in pulse current P. Based on the results of the first and second resistance evaluations, an abnormality in power line L1 is diagnosed. In at least one of the first and second resistance evaluations, multiple voltage change values ​​are obtained where at least one of the start and end points of the voltage change is different, and multiple resistance evaluations are performed. As a result, many resistance evaluations can be performed using a single pulse current P. Therefore, it is not necessary to generate pulse current P multiple times in power line diagnosis, and the time required for power line diagnosis can be shortened. Thus, an abnormality in power line L1 can be appropriately diagnosed. 【0121】 Preferably, in the hydraulic control unit 5, the diagnostic unit 52c performs a power line diagnosis when it is determined that the voltage V of the power line L1 is stable. This improves the reliability of the power line diagnosis. 【0122】 Preferably, in the hydraulic control unit 5, the diagnostic unit 52c acquires the voltage change amount based on the first voltage V1, which is the voltage V of the power line L1 acquired when the current value C is the first current value C1, and the second voltage V2, which is the voltage V of the power line L1 acquired when the current value C is the second current value C2, in the first resistance value evaluation, and in the second resistance value evaluation, it acquires the voltage change amount based on the second voltage V2 and the third voltage V3, which is the voltage V of the power line L1 acquired when the current value C is the third current value C3. This appropriately realizes the first resistance value evaluation and the second resistance value evaluation. 【0123】 Preferably, in the hydraulic control unit 5, the timing of acquiring the second voltage V2 is biased towards the latter half of the period during which the current value C in the pulse current P is the second current value C2, rather than the first half. This suppresses the acquisition of a voltage V that is decreasing as the second voltage V2, thereby improving the reliability of the first resistance value evaluation and the second resistance value evaluation. 【0124】 Preferably, in the hydraulic control unit 5, there are multiple timings for acquiring the second voltage V2, and the diagnostic unit 52c gives more weight to the evaluation of resistance values ​​using the second voltage V2 acquired later than to the evaluation of resistance values ​​using the second voltage V2 acquired earlier. This allows for a greater weight to be given to the evaluation of resistance values ​​using the second voltage V2, which is less likely to be a voltage V that is decreasing, thereby improving the reliability of the first resistance value evaluation and the second resistance value evaluation. 【0125】 Preferably, in the hydraulic control unit 5, the timing for acquiring the third voltage V3 is at a time that is longer than a reference time after the transition timing from the second current value C2 to the third current value C3. This suppresses the acquisition of the rising voltage V as the third voltage V3, thereby improving the reliability of the second resistance value evaluation. 【0126】 Preferably, in the hydraulic control unit 5, there are multiple timings for acquiring the third voltage V3, and the diagnostic unit 52c gives more weight to the evaluation of the resistance value using the third voltage V3 acquired later than to the evaluation of the resistance value using the third voltage V3 acquired earlier. This improves the reliability of the second resistance value evaluation because it is possible to give more weight to the evaluation of the resistance value using the third voltage V3, which is less likely to be a rising voltage V. 【0127】 Preferably, in the hydraulic control unit 5, there are multiple timings for acquiring the first voltage V1, the second voltage V2, and the third voltage V3, and the time interval for acquiring the second voltage V2 is shorter than the time interval for acquiring the first voltage V1 and the third voltage V3. This allows, for example, in the above example, to shorten the period during which the suction valve 31 is in a closed state. Thus, in the power line diagnosis, the situation in which the hydraulic pressure of the brake fluid in the wheel cylinder 24 of the braking mechanism (rear wheel braking mechanism 14 in the above example) to which the suction valve 31 to which current is applied cannot be increased by the rider's braking operation is suppressed. 【0128】 Preferably, in the hydraulic control unit 5, there are multiple acquisition timings for the first voltage V1, the second voltage V2, and the third voltage V3, and the number of acquisition timings for the second voltage V2 is smaller than the number of acquisition timings for the first voltage V1 and the third voltage V3. This allows, for example, in the above example, to shorten the period during which the suction valve 31 is in a closed state. Thus, in the power line diagnosis, the situation in which the hydraulic pressure of the brake fluid in the wheel cylinder 24 of the braking mechanism (rear wheel braking mechanism 14 in the above example) to which the suction valve 31 to which current is applied cannot be increased by the rider's braking operation is suppressed. 【0129】 Preferably, in the hydraulic control unit 5, the open / closed state of the solenoid valve (in the above example, the suction valve 31) switches between an open state and a closed state in response to the generation of a pulse current P. This shortens the period during which the suction valve 31 is in the closed state, compared to, for example, the case where the open / closed state of the suction valve 31 does not switch between an open state and a closed state in response to the generation of a pulse current P. Thus, the situation in which the hydraulic pressure of the brake fluid in the wheel cylinder 24 of the braking mechanism (in the above example, the rear wheel braking mechanism 14) to which the suction valve 31 to which current is applied in the power line diagnosis belongs cannot be increased by the rider's braking operation. 【0130】 Preferably, in the hydraulic control unit 5, the vehicle 100 is a saddle-type vehicle. This allows for proper diagnosis of abnormalities in the power line L1 when the hydraulic control unit 5 is mounted on a saddle-type vehicle. 【0131】 The present invention is not limited to the descriptions of embodiments. For example, only a portion of the embodiments may be implemented. 【0132】 For example, the first and second examples of power line diagnostics described above may be combined and employed. For instance, in at least one of the first and second resistance evaluations performed for at least one pulse current in the first example of power line diagnostics, multiple voltage change amounts may be obtained where at least one of the start and end points of the voltage change is different from each other, and multiple resistance evaluations may be performed. [Explanation of symbols] 【0133】 1 Body, 2 Handle, 3 Front wheel, 3a Rotor, 4 Rear wheel, 4a Rotor, 5 Hydraulic control unit, 6 Notification device, 10 Brake system, 11 First brake operation unit, 12 Front wheel braking mechanism, 13 Second brake operation unit, 14 Rear wheel braking mechanism, 21 Master cylinder, 22 Reservoir, 23 Brake caliper, 24 Wheel cylinder, 25 Main flow path, 26 Sub-flow path, 31 Intake valve, 32 Release valve, 33 Accumulator, 34 Pump, 35 Switching element, 41 Front wheel speed sensor, 42 Rear wheel speed sensor, 43 Voltage sensor, 51 Hydraulic control mechanism, 51a Base unit, 52 Control device, 52a Acquisition unit, 52b Control unit, 52c Diagnostic unit, 100 Vehicle, B1 Power supply, C Current value, C1 First current value, C2 Second current value, C3 Third current value, Cmax maximum value, Cmid intermediate value, Cmin minimum value, L1 power line, P pulse current, P1 pulse current, P2 pulse current, P3 pulse current, P4 pulse current, P11 pulse current, P12 pulse current, P13 pulse current, P14 pulse current, V voltage, V1 first voltage, V2 second voltage, V3 third voltage.

Claims

[Claim 1] A hydraulic control unit (5) used in the brake system (10) of a vehicle (100), A hydraulic pressure control mechanism (51) is electrically connected to a power source (B1) via a power line (L1) and includes solenoid valves (31, 32) that control the hydraulic pressure generated in the wheel cylinder (24), A control device (52) that controls the operation of the hydraulic pressure control mechanism (51), Equipped with, The control device (52) includes a diagnostic unit (52c) that performs a power line diagnosis to diagnose an abnormality in the power line (L1) based on the voltage change in the power line (L1) when the current applied from the power supply (B1) to the solenoid valves (31, 32) via the power line (L1) is changed. The diagnostic unit (52c) performs the power line diagnosis as follows: The current value (C) of the current applied to the solenoid valves (31, 32) generates a single rectangular wave-shaped pulse current (P) that transitions in the order of a first current value (C1), a second current value (C2) that is greater than the first current value (C1), and a third current value (C3) that is less than the second current value (C2). A first resistance value evaluation is performed to evaluate the resistance value of the power supply line (L1) based on the amount of voltage change in the power supply line (L1) before and after the current value (C) changes from the first current value (C1) to the second current value (C2) in the pulse current (P). A second resistance value evaluation is performed to evaluate the resistance value based on the amount of voltage change before and after the current value (C) transitions from the second current value (C2) to the third current value (C3) in the pulse current (P). Based on the results of the first resistance value evaluation and the second resistance value evaluation, an abnormality in the power line (L1) is diagnosed. In at least one of the first resistance value evaluation and the second resistance value evaluation, a plurality of voltage change amounts are obtained in which at least one of the start and end points of the voltage change is different from each other, and the resistance value is evaluated in a plurality of ways. Hydraulic control unit. [Claim 2] The diagnostic unit (52c) performs the power line diagnosis when it is determined that the voltage (V) of the power line (L1) is stable. The hydraulic control unit according to claim 1. [Claim 3] The diagnostic unit (52c) is In the first resistance value evaluation, the voltage change amount is obtained based on the first voltage (V1), which is the voltage (V) of the power line (L1) acquired when the current value (C) is the first current value (C1), and the second voltage (V2), which is the voltage (V) of the power line (L1) acquired when the current value (C) is the second current value (C2). In the second resistance value evaluation, the voltage change amount is obtained based on the second voltage (V2) and the third voltage (V3), which is the voltage (V) of the power line (L1) acquired when the current value (C) is equal to the third current value (C3). The hydraulic control unit according to claim 1. [Claim 4] The timing for acquiring the second voltage (V2) is biased towards the latter half of the period during which the current value (C) in the pulse current (P) is equal to the second current value (C2), rather than the first half. The hydraulic control unit according to claim 3. [Claim 5] There are multiple timings for acquiring the second voltage (V2), The diagnostic unit (52c) gives more weight to the evaluation of the resistance value using the second voltage (V2), which has a later acquisition timing, compared to the evaluation of the resistance value using the second voltage (V2), which has an earlier acquisition timing. The hydraulic control unit according to claim 3. [Claim 6] The timing for acquiring the third voltage (V3) is a time interval that is longer than or equal to the reference time elapsed from the transition timing from the second current value (C2) to the third current value (C3). The hydraulic control unit according to claim 3. [Claim 7] There are multiple timings for acquiring the third voltage (V3), The diagnostic unit (52c) gives more weight to the evaluation of the resistance value using the third voltage (V3), which has a later acquisition timing, compared to the evaluation of the resistance value using the third voltage (V3), which has an earlier acquisition timing. The hydraulic control unit according to claim 3. [Claim 8] There are multiple timings for acquiring the first voltage (V1), the second voltage (V2), and the third voltage (V3). The time interval for acquiring the second voltage (V2) is shorter than the time interval for acquiring the first voltage (V1) and the third voltage (V3). The hydraulic control unit according to claim 3. [Claim 9] There are multiple timings for acquiring the first voltage (V1), the second voltage (V2), and the third voltage (V3). The number of acquisition timings for the second voltage (V2) is less than the number of acquisition timings for the first voltage (V1) and the third voltage (V3). The hydraulic control unit according to claim 3. [Claim 10] The open / closed state of the solenoid valves (31, 32) switches between an open state and a closed state in response to the generation of the pulse current (P). A hydraulic control unit according to any one of claims 1 to 9. [Claim 11] The aforementioned vehicle (100) is a saddle-type vehicle. The hydraulic control unit according to claim 1. [Claim 12] A method for diagnosing a hydraulic control unit (5) used in the brake system (10) of a vehicle (100), The hydraulic control unit (5) is A hydraulic pressure control mechanism (51) is electrically connected to a power source (B1) via a power line (L1) and includes solenoid valves (31, 32) that control the hydraulic pressure generated in the wheel cylinder (24), A control device (52) that controls the operation of the hydraulic pressure control mechanism (51), Equipped with, The diagnostic unit (52c) of the control device (52) performs a power line diagnosis to diagnose an abnormality in the power line (L1) based on the voltage change in the power line (L1) when the current applied from the power supply (B1) to the solenoid valves (31, 32) via the power line (L1) is changed. The diagnostic unit (52c) in the power line diagnosis, The current value (C) of the current applied to the solenoid valves (31, 32) generates a single rectangular wave-shaped pulse current (P) that transitions in the order of a first current value (C1), a second current value (C2) that is greater than the first current value (C1), and a third current value (C3) that is less than the second current value (C2). A first resistance value evaluation is performed to evaluate the resistance value of the power line based on the amount of voltage change in the power line (L1) before and after the current value (C) changes from the first current value (C1) to the second current value (C2) in the pulse current (P). A second resistance value evaluation is performed to evaluate the resistance value based on the amount of voltage change before and after the current value (C) transitions from the second current value (C2) to the third current value (C3) in the pulse current (P). Based on the results of the first resistance value evaluation and the second resistance value evaluation, an abnormality in the power line (L1) is diagnosed. In at least one of the first resistance value evaluation and the second resistance value evaluation, a plurality of voltage change amounts are obtained in which at least one of the start and end points of the voltage change is different from each other, and the resistance value is evaluated in a plurality of ways. Diagnostic methods.

Images