JP4432335B2 - Pneumatic-hydraulic conversion type brake device and its electronic control unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pneumatic-hydraulic pressure-converting brake device that converts air pressure to hydraulic pressure and applies a braking force to wheels, and an electronic control unit thereof .
[0002]
[Prior art]
Conventionally, a brake valve that is connected to an air tank that stores compressed air and outputs an air pressure according to an operation amount of a brake pedal, an air master cylinder that generates a hydraulic pressure according to the air pressure supplied from the brake valve, and the air Connected in parallel with the brake valve between the air tank and the air master cylinder, the wheel cylinder to which the hydraulic pressure delivered from the master cylinder is supplied, the anti-skid hydraulic pressure control unit that controls the hydraulic pressure supplied to the wheel cylinder An air pressure-hydraulic pressure conversion type brake control device that provides a solenoid opening / closing air valve and opens the solenoid opening / closing air valve to apply a braking force to the wheel when a slip of the driving wheel is detected at the start of the vehicle is disclosed in Japanese Utility Model Registration No. 2629296. It is described in.
[0003]
[Patent Document 1]
Utility Model Registration No. 2569292 (pages 4 to 6, FIG. 1)
[0004]
[Problems to be solved by the invention]
In the air pressure-hydraulic pressure conversion type brake control device as described above, performing a self-diagnosis of the air valve is important for promptly informing the driver of the failure. However, if the air valve is opened for a short period of time for self-diagnosis, air flows from the air tank to the air master cylinder and noise is generated, which may cause driver discomfort or apply unnecessary braking force to the wheels. was there.
[0005]
The present invention has been made to solve such conventional problems, and the air valve connected in parallel with the brake valve between the air tank and the air master cylinder does not generate noise or generate unnecessary braking force. It is to provide a pneumatic pressure-hydraulic conversion brake device and its electronic control unit that can be diagnosed.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, the structural feature of the invention described in claim 1 is that a brake valve connected to an air tank for storing compressed air and outputting an air pressure corresponding to an operation amount of a brake pedal, and the brake valve An air master cylinder that sends out hydraulic pressure according to the air pressure supplied from the wheel, a wheel cylinder that is supplied with hydraulic pressure sent from the air master cylinder, and a hydraulic pressure that controls the hydraulic pressure supplied to the wheel cylinder A control unit, an air valve connected in parallel with the brake valve between the air tank and the air master cylinder, and control of the hydraulic pressure control unit and the air valve based on a signal from a sensor that detects a vehicle running state In a pneumatic-hydraulic pressure conversion type brake device having an electronic control unit for outputting a signal, the hydraulic pressure control unit The self-diagnosis of the air valve is performed by driving the air valve for a minute time during which compressed air does not substantially move from the air tank to the air master cylinder. Means to execute is provided.
[0007]
The structural feature of the invention according to claim 2 is that, in claim 1, the minute time for opening the air valve is about 0.002 seconds.
[0008]
A structural feature of the invention according to claim 3 is that a brake valve connected to an air tank for storing compressed air and outputting an air pressure according to an operation amount of a brake pedal, and a liquid according to the air pressure supplied from the brake valve are provided. An air master cylinder that generates pressure, a wheel cylinder to which hydraulic pressure is supplied from the air master cylinder, and a hydraulic pressure that is connected between the air master cylinder and the wheel cylinder and that is supplied to the wheel cylinder A hydraulic pressure control unit for controlling the vehicle, an air valve connected in parallel with the brake valve between the air tank and the air master cylinder, and the hydraulic pressure control unit based on a signal from a sensor for detecting a vehicle running state And an air pressure-hydraulic conversion type brake equipped with an electronic control unit for outputting a control signal to the air valve In the apparatus, the electronic control unit is in a state where the connection between the air master cylinder and the wheel cylinder is disconnected by the hydraulic pressure control unit when the hydraulic pressure control unit is in an inoperative state and the self-diagnosis time of the air valve. And means for driving the air valve to execute self-diagnosis for the air valve.
[0009]
According to a fourth aspect of the present invention, in any one of the first to third aspects, the wheel to which the hydraulic pressure is supplied to the wheel cylinder to apply a braking force is a driving wheel, and the air valve is It is a solenoid open / close air valve.
[0010]
The structural feature of the invention according to claim 5 is that, in any one of claims 1 to 4, the self-diagnosis time of the air valve is an initial system state when the engine is started.
The structural feature of the invention according to claim 6 is that a brake valve connected to an air tank for storing compressed air and outputting an air pressure corresponding to an operation amount of a brake pedal, and a liquid corresponding to the air pressure supplied from the brake valve are provided. An air master cylinder for delivering pressure, a wheel cylinder to which hydraulic pressure delivered from the air master cylinder is supplied, a hydraulic pressure control unit for controlling hydraulic pressure supplied to the wheel cylinder, the air tank and the air The hydraulic pressure control based on a signal from a sensor that is applied to an air pressure-hydraulic pressure conversion brake device including an air valve connected in parallel with the brake valve between a master cylinder and a vehicle running state In an electronic control unit of a pneumatic pressure-hydraulic pressure conversion brake device that outputs a control signal to the unit and the air valve, When the fluid pressure control unit is in the non-operating state and the self-diagnosis timing of the air valve, the air valve is driven for a minute time during which compressed air does not substantially move from the air tank to the air master cylinder. Means for executing the self-diagnosis is provided.
The structural feature of the invention according to claim 7 is that a brake valve connected to an air tank for storing compressed air and outputting an air pressure corresponding to an operation amount of a brake pedal, and a liquid corresponding to the air pressure supplied from the brake valve are provided. An air master cylinder that generates pressure, a wheel cylinder to which hydraulic pressure is supplied from the air master cylinder, and a hydraulic pressure that is connected between the air master cylinder and the wheel cylinder and that is supplied to the wheel cylinder Applied to a pneumatic-hydraulic pressure converting brake device comprising a hydraulic pressure control unit for controlling the pressure and an air valve connected in parallel with the brake valve between the air tank and the air master cylinder. A control signal is output to the hydraulic pressure control unit and the air valve based on a signal from a sensor for detecting In the electronic control unit of the pneumatic-hydraulic pressure conversion brake device, the hydraulic pressure control unit connects the air master cylinder and the wheel cylinder when the hydraulic pressure control unit is in an inoperative state and the self-diagnosis time of the air valve. In this state, the air valve is driven to perform a self-diagnosis on the air valve .
[0011]
[Operation and effect of the invention]
In the invention according to claim 1 configured as described above, when the brake pedal is depressed and the brake valve is actuated, the air pressure corresponding to the operation amount of the brake pedal is supplied to the air master cylinder, and The hydraulic pressure is supplied to the wheel cylinder to apply a braking force to the wheel. For example, when the accelerator is depressed and the wheel slips when the vehicle starts, the air valve is opened, compressed air is supplied from the air tank to the air master cylinder, and a braking force is applied to the wheel so as to suppress the slip. In order to self-diagnose whether or not the air valve operates normally, the hydraulic pressure control unit that applies braking force to the wheels according to the vehicle running state is in the non-operating state and the air valve is switched from the air tank to the air master cylinder at the self-diagnosis time of the air valve. The operation of the air valve is checked by driving the air valve for a minute time during which the compressed air does not move substantially. Thereby, at the time of self-diagnosis of the air valve, air does not flow from the air tank to the air master cylinder, no abnormal noise is generated, and the driver is not uncomfortable. Furthermore, it is possible to prevent unnecessary braking force from being applied to the wheels. In addition, since the air valve is opened while the hydraulic pressure control unit is not in operation, the brake force application control to the wheels is not affected.
[0012]
In the invention according to claim 2 configured as described above, since the air valve is opened for a short time of about 0.002 seconds for self-diagnosis, a substantial flow of air from the air tank to the air master cylinder does not occur. Air valve operation check can be performed.
[0013]
In the invention according to claim 3 configured as described above, the connection between the air master cylinder and the wheel cylinder is hydraulically controlled during the self-diagnosis time of the air valve in order to self-diagnose whether the air valve operates normally. Air valve operation check is performed by shutting off by the unit and opening the air valve, so that air does not flow from the air master cylinder to the wheel cylinder during self-diagnosis, and unnecessary braking force is applied to the wheel by self-diagnosis of the air valve There is no.
[0014]
In the invention according to claim 4 configured as described above, when the drive wheel slips more than an allowable value, the solenoid open / close air valve is opened and compressed air is supplied from the air tank to the air master cylinder, and the drive is controlled to suppress the slip. A braking force is applied to the wheel. This self-diagnosis of the solenoid open / close air valve can be accurately performed without generating an abnormal noise during diagnosis and without applying unnecessary braking force to the wheels.
[0015]
In the invention according to claim 5 configured as described above, since the self-diagnosis is performed to determine whether or not the air valve operates normally in the initial system state when the engine is started, it is effective to drive while the air valve is broken. Can be prevented.
In the invention according to claim 6 configured as described above, the electronic control unit of the air pressure-hydraulic pressure conversion type brake device performs a self-diagnosis on whether the air valve operates normally according to the vehicle running state. Check the operation of the air valve by driving the air valve for a very short period of time during which the compressed air does not move from the air tank to the air master cylinder during the self-diagnosis time of the air valve when the hydraulic pressure control unit that applies the braking force to the wheels is inactive. Do. Thereby, at the time of self-diagnosis of the air valve, air does not flow from the air tank to the air master cylinder, no abnormal noise is generated, and the driver is not uncomfortable. Furthermore, it is possible to prevent unnecessary braking force from being applied to the wheels. In addition, since the air valve is opened while the hydraulic pressure control unit is not in operation, the brake force application control to the wheels is not affected.
In the invention according to claim 7 configured as described above, the electronic control unit of the air pressure-hydraulic pressure converting brake device performs self-diagnosis on whether or not the air valve operates normally. The air master cylinder and wheel cylinder are disconnected by the hydraulic control unit and the air valve is opened to check the operation of the air valve.Therefore, air does not flow from the air master cylinder to the wheel cylinder during self-diagnosis. The self-diagnosis prevents unnecessary braking force from being applied to the wheels.
[0016]
Embodiment
Embodiments of a pneumatic-hydraulic pressure conversion brake device according to the present invention will be described below with reference to the drawings. In the air pressure-hydraulic pressure converting brake device 1 according to the present embodiment, when the driver steps on the brake pedal 2, the braking force is applied to the left and right rear wheels 3rl and 3rr and the left and right front wheels 3fl and 3fr, respectively. A rear wheel brake system 4r and a front wheel brake system 4f are provided separately. In FIG. 1, the components constituting the rear wheel and front wheel brake systems 4r and 4f are the same in configuration and operation, and therefore, the corresponding numerals are added to the same arithmetic numerals with the letters r and f, respectively. A reference symbol is assigned to distinguish between the front and rear. Further, the left and right are distinguished by adding l and r after the Roman letters r and f that distinguish the front and rear wheels to the same components in the left and right wheels. In the specification, when components are shown without distinction between front, back, left, and right, only the corresponding arithmetic numbers are given as reference numbers.
[0017]
Reference numeral 5 denotes an air tank for storing compressed air, and the sections 5r and 5f divided for the rear wheel and front wheel brake systems are connected to the input ports of the rear wheel and front wheel brake valves 6r and 6f for the dual brake valve 6. . When the brake pedal 2 is depressed by the driver, the dual brake valve 6 outputs air pressure corresponding to the operation amount as the depression amount from the output port of each brake valve 6r, 6f. The output ports of the brake valves 6r and 6f are connected to the air pressure chambers 9r and 9f of the air master cylinders 8r and 8f via the check valves 7r and 7f. The air pressure output from the brake valves 6r and 6f is the air pressure chamber 9r, It acts on the air pistons 10r and 10f slidably fitted to 9f, presses the master pistons of the master cylinders 11r and 11f, and sends the hydraulic pressure to the pipe lines 12r and 12f. The hydraulic pressure delivered from the master cylinders 11r and 11f is supplied to the left and right wheel cylinders 14rl, 14rr, 14fl, and 14fr via the hydraulic pressure control unit 13 through the pipelines 12r and 12f, respectively, for example, expanding the brake shoes of the drum brake. Thus, braking force is applied to the left and right rear wheels 3rl and 3rr and the left and right front wheels 3fl and 3fr. Reference numeral 19 denotes a reservoir for storing brake fluid, which replenishes the master cylinders 11r and 11f with brake fluid.
[0018]
Solenoid open / close air valves 15r, 15f are connected in parallel with the brake valves 6r, 6f between the sections 5r, 5f of the air tank 5 and the pneumatic chambers 9r, 9f of the air master cylinders 8r, 8f. The check valves 7r and 7f prevent the compressed air that has passed through the air valves 15r and 15f from flowing back to the brake valves 6r and 6f.
[0019]
The hydraulic pressure control unit 13 is configured by connecting various solenoid valves to the pipe lines 12r and 12f. Reference numerals 16r and 16f are solenoid hydraulic pressure proportional control valves for maintaining a set hydraulic pressure in the wheel cylinder 14 after the brake pedal 2 is released when starting a slope, and an inclination sensor 30 indicates that the vehicle has stopped on the slope. Is detected and is shifted to the left position. Even if the inlet side hydraulic pressure drops to zero, the outlet side hydraulic pressure is applied to the solenoids 17r and 17f in accordance with the vehicle front-rear direction tilt angle detected by the tilt sensor 30. Is maintained at a set pressure proportional to the applied voltage. The vehicle is shifted to the right position through the entrance and exit except when the vehicle is stopped on a slope. A check valve that allows a flow from the inlet side to the outlet side is connected between the inlets and outlets of the solenoid hydraulic pressure proportional control valves 16r and 16f. A brake fluid pressure sensor 28 for detecting the brake fluid pressure is connected to the inlet side of the solenoid fluid pressure proportional control valve 16r on the rear wheel side.
[0020]
The pipes 12r and 12f connected to the outlets of the solenoid hydraulic pressure proportional control valves 16r and 16f are branched to the left and right rear wheel wheel cylinders 14rl and 14rr and the left and right front wheel wheel cylinders 14fl and 14fr, respectively. , 18rr and 18fl and 18fr, respectively. A check valve that allows the flow from the outlet side to the inlet side is connected between the inlets and outlets of the solenoid on-off valves 18rl, 18rr, 18fl, and 18fr. 19r and 19f are hydraulic pumps that are driven to rotate by the motor 20 to suck in brake fluid from the reservoirs 21r and 21f through the check valves, and the solenoid on-off valves 18rl and 18rr and 18fl and 18fr through the check valves. Pump up upstream. The reservoirs 21r and 21f are configured by sealing a bottomed casing with a piston urged by a weak compression spring. 22r and 22f are dampers for absorbing hydraulic pressure pulsations discharged from the hydraulic pumps 19r and 19f. Solenoid on / off valves 23rl, 23rr and 23fl, 23fr are connected between the outlets of the solenoid on / off valves 18rl, 18rr and 18fl, 18fr and the reservoirs 21r and 21f, respectively.
[0021]
The electronic control unit 25 with a built-in CPU of the air pressure-hydraulic pressure converting brake device 1 includes a wheel speed sensor 26 that detects the wheel speed of each wheel, a foot brake sensor 27 that detects whether or not the brake pedal 2 is depressed, and brake fluid. Each detection signal is input from a brake fluid pressure sensor 28 that detects pressure, a throttle opening sensor 29 that detects the amount of depression of the accelerator, and a tilt sensor 30 that detects a tilt angle in the vehicle longitudinal direction, and control is performed based on these detection signals. The program and self-diagnosis program are executed, control signals are output to the air valves 15r, 15f and the hydraulic pressure control unit 13, etc. to control the application of braking force to the wheels, and when there is an abnormality such as failure of the air valves 15r, 15f, an abnormal lamp 31 is turned on and the alarm buzzer 32 is sounded.
[0022]
Next, the operation of the air pressure-hydraulic pressure converting brake device according to the above embodiment will be described. When the brake pedal 2 is depressed and the brake valves 6r and 6f are opened, the air pressure corresponding to the depression amount is supplied to the air pressure chambers 9r and 9f of the air master cylinders 8r and 8f, and the wheel cylinders 14 from the master cylinders 11r and 11f. The brake fluid pressure is supplied to each wheel 3 and a braking force is applied to each wheel 3. When the foot brake sensor 27 detects that the brake pedal 2 is depressed and the brake fluid pressure detected by the brake fluid pressure sensor 28 exceeds a predetermined value, the electronic control unit 25 performs anti-skid brake control to open / close each solenoid. The valves 18 and 23 are opened and closed, and the braking force is increased, held and decreased so that the wheels 3 do not slip with respect to the road surface.
[0023]
When the throttle opening sensor 29 detects that the accelerator is depressed when the vehicle starts, the electronic control unit 25 performs drive wheel slip control. From the vehicle speed V calculated from the average value of the wheel speeds Sfl and Sfr of the driven wheels detected by the wheel speed sensors 26fl and 26fr, for example, the front wheels 3fl and 3fr, and the wheel speeds Srl and Srr of the driving wheels, for example, the rear wheels 3rl and 3rr. When a driving wheel slipping more than an appropriate slip ratio is detected, for example, when the left rear wheel 3rl slips excessively, the air valve 15r is opened, and air pressure is supplied to the air pressure chamber 9r of the air master cylinder 8r. The hydraulic pressure is sent from the master cylinder 11r, the solenoid on-off valve 18rl is opened, the hydraulic pressure is supplied to the wheel cylinder 14rl for the left rear wheel 3rl, and the braking force is applied to the left rear wheel. When the wheel speed Srl of the left rear wheel 3rl becomes too low, the solenoid on-off valve 18rl is closed and the solenoid on-off valve 23rl is opened to reduce the braking force. When the slip ratio of the left rear wheel 3rl becomes an appropriate value, the solenoid on-off valve 23rl is closed and the hydraulic pressure of the wheel cylinder 14rl is maintained. Since the right rear wheel 3rr does not slip excessively, the solenoid on-off valve 18rr is closed. The hydraulic pumps 19r and 19f are rotationally driven by the motor 20 at the start of the drive wheel slip control, and the brake fluid discharged to the reservoir 21r by opening the solenoid on-off valve 23rl is upstream of the solenoid on-off valves 18rl and 18rr by the hydraulic pump 19r. Back to the side.
[0024]
In order to self-diagnose whether or not such air valves 15r and 15f operate normally, the self-diagnosis program shown in FIG. 2 is executed, and is the system initial state where the electronic control unit 25 is first started up when the engine is started? It is determined whether or not (step S1). The system initial state is a self-diagnosis time when the hydraulic control unit 13 is in an inoperative state and the self-diagnosis of the air valves 15r and 15f is executed. When the foot brake sensor 27 detects that the brake is not depressed and the driving wheel slip control or the like for opening the air valves 15r and 15f is not executed, it is determined that the hydraulic pressure control unit 13 is in an inoperative state. (Step 2). If it is determined that the hydraulic pressure control unit 13 is inactive, it is determined whether or not the vehicle has stopped for a certain time, for example, 5 minutes or more (step S3), and a predetermined time, for example, 30 minutes has elapsed since the previous self-diagnosis was executed. Is determined (step S4), and when the vehicle stops for a certain time or a predetermined time has passed since the previous self-diagnosis, it is determined that it is the self-diagnosis time of the air valves 15r and 15f. If it is determined that the hydraulic pressure control unit 13 is in a non-operating state and the self-diagnosis time for executing the self-diagnosis of the air valves 15r, 15f is reached, the electronic control unit 25 changes the air tanks 5r, 5f to the air master cylinders 8r, 8f. In order to drive the air valves 15r and 15f for a minute time during which the compressed air does not substantially move, a voltage is applied to the solenoid coils 33r and 33f of the air valves 15r and 15f for a minute time of about 0.002 seconds (Steps S5, S7, S8), the ammeters 34r and 34f connected to the solenoid coils 33r and 33f detect the presence or absence of current (step S6), the solenoid coils 33r and 33f are checked for abnormalities, and the air valves 15r and 15f are self-diagnosed. To do. If there is no current due to disconnection of the solenoid coils 33r, 33f, etc., it is determined that the air valves 15r, 15f are abnormal, the lamp 31 is turned on, and the buzzer 32 is sounded to alarm (step S9). If there is no abnormality in the solenoid coils 33r and 33f, the self-diagnosis program is terminated.
[0025]
In the self-diagnosis program shown in FIG. 2, the air valves 15r and 15f are driven for a very short time during which compressed air does not substantially move from the air tanks 5r and 5f to the air master cylinders 8r and 8f, and the air valves 15r and 15f are self-diagnosed. However, in the self-diagnosis program shown in FIG. 3, when it is determined that the hydraulic pressure control unit 13 is in the non-operating state and the self-diagnosis time for executing the self-diagnosis of the air valves 15 r and 15 f is reached, the solenoid on-off valve 18 is closed. In this state, the connection between the air master cylinders 8r and 8f and the wheel cylinder 14 is cut off (step S10), and a voltage is applied to the solenoid coils 33r and 33f for a short time to drive the air valves 15r and 15f (step S5). S7 ', S8), the presence or absence of current is detected by the ammeters 34r, 34f (steps) S6) The solenoid coils 33r and 33f are checked for abnormalities, and self-diagnosis is performed on the air valves 15r and 15f.
[0026]
In the above embodiment, the air valves 15r and 15f are opened and closed in the drive wheel slip control. However, the turning behavior of the vehicle is detected by a lateral G sensor or the like, and the air valves 15r and 15f are opened during traveling to brake necessary wheels. Traction that obtains optimal driving force by combining vehicle behavior control to increase the stability of the vehicle by applying force, or applying braking force to the driving wheels by opening the air valves 15r and 15f during running and fuel injection control The air pressure-hydraulic pressure converting brake device according to the present invention may be used for control or the like.
[Brief description of the drawings]
FIG. 1 is a system diagram showing a block diagram of an electronic control unit in a hydraulic circuit diagram of an embodiment of a pneumatic-hydraulic pressure converting brake device.
FIG. 2 is a diagram showing a self-diagnosis program for an air valve.
FIG. 3 is a diagram showing another self-diagnosis program of the air valve.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Air pressure-hydraulic pressure conversion type brake device, 2 ... Brake pedal, 3 ... Wheel, 4 ... Brake system, 5 ... Air tank, 6 ... Dual brake valve, 6r, 6f ... Brake valve, 8 ... Air master cylinder, 9r, 9f ... Air pressure chamber, 11r, 11f ... Master cylinder, 12r, 12f ... Pipe line, 13 ... Fluid pressure control unit, 14 ... Wheel cylinder, 15 ... Solenoid opening / closing air valve (air valve), 18, 23 ... Solenoid opening / closing valve, 19 ... Hydraulic pump, 25 ... electronic control unit, 26 ... wheel speed sensor, 27 ... foot brake sensor, 28 ... brake hydraulic pressure sensor, 29 ... throttle opening sensor, 33 ... solenoid coil, 34 ... ammeter.

Claims (7)

  A brake valve connected to an air tank for storing compressed air and outputting an air pressure according to the operation amount of the brake pedal, an air master cylinder for sending a hydraulic pressure according to the air pressure supplied from the brake valve, and the air master cylinder A wheel cylinder to which the hydraulic pressure delivered from the vehicle is supplied, a hydraulic pressure control unit for controlling the hydraulic pressure supplied to the wheel cylinder, and the brake valve connected in parallel between the air tank and the air master cylinder In the pneumatic-hydraulic pressure conversion type brake device, comprising the air valve and the hydraulic pressure control unit and an electronic control unit that outputs a control signal to the air valve based on a signal from a sensor that detects a vehicle running state. When the pressure control unit is in the non-operating state and the self-diagnosis time of the air valve, A pneumatic-hydraulic pressure-converting brake comprising means for driving the air valve for a minute time during which compressed air does not substantially move from the air tank to the air master cylinder to execute self-diagnosis on the air valve. apparatus.   2. The air pressure-hydraulic pressure converting brake device according to claim 1, wherein the minute time for opening the air valve is about 0.002 seconds. A brake valve connected to an air tank for storing compressed air and outputting an air pressure corresponding to an operation amount of a brake pedal, an air master cylinder generating a hydraulic pressure corresponding to an air pressure supplied from the brake valve, and the air master cylinder A wheel cylinder to which a hydraulic pressure delivered from is supplied, a hydraulic pressure control unit that is connected between the air master cylinder and the wheel cylinder and controls the hydraulic pressure supplied to the wheel cylinder, the air tank, An air valve connected in parallel with the brake valve between the air master cylinder and an electronic control unit that outputs a control signal to the hydraulic pressure control unit and the air valve based on a signal from a sensor that detects a vehicle running state In the air pressure-hydraulic pressure conversion brake device provided,
The electronic control unit is configured such that the air pressure control unit is in a non-operating state and the air valve is disconnected from the air master cylinder and the wheel cylinder at the self-diagnosis time of the air valve. A pneumatic-hydraulic-converting brake device having means for driving the air valve to perform self-diagnosis on the air valve.   4. The air pressure-liquid according to claim 1, wherein the wheel supplied with the hydraulic pressure to the wheel cylinder and applied with a braking force is a driving wheel, and the air valve is a solenoid open / close air valve. Pressure conversion brake device.   5. The air pressure-hydraulic pressure converting brake device according to claim 1, wherein the self-diagnosis time of the air valve is a system initial state when the engine is started. A brake valve connected to an air tank for storing compressed air and outputting an air pressure according to an operation amount of a brake pedal, an air master cylinder for sending a hydraulic pressure according to the air pressure supplied from the brake valve, and the air master cylinder A wheel cylinder to which the hydraulic pressure delivered from the vehicle is supplied, a hydraulic pressure control unit for controlling the hydraulic pressure supplied to the wheel cylinder, and the brake valve connected in parallel between the air tank and the air master cylinder A pneumatic-hydraulic pressure brake that is applied to a pneumatic-hydraulic pressure-converting brake device, and outputs a control signal to the hydraulic pressure control unit and the air valve based on a signal from a sensor that detects a vehicle running state. In the electronic control unit of the pressure conversion brake device,
When the hydraulic pressure control unit is in a non-operating state and the self-diagnosis timing of the air valve, the air valve is driven for a minute time during which compressed air does not substantially move from the air tank to the air master cylinder. An electronic control unit for a pneumatic-hydraulic pressure-converting brake device, characterized in that a means for executing self-diagnosis is provided. A brake valve connected to an air tank for storing compressed air and outputting an air pressure corresponding to an operation amount of a brake pedal, an air master cylinder generating a hydraulic pressure corresponding to an air pressure supplied from the brake valve, and the air master cylinder A wheel cylinder to which a hydraulic pressure delivered from is supplied, a hydraulic pressure control unit that is connected between the air master cylinder and the wheel cylinder and controls the hydraulic pressure supplied to the wheel cylinder, the air tank, The hydraulic pressure is applied to a pneumatic-hydraulic pressure converting brake device having an air valve connected in parallel with the brake valve between an air master cylinder and the hydraulic pressure based on a signal from a sensor for detecting a vehicle running state. Electric power of a pneumatic-hydraulic conversion brake device that outputs a control signal to the control unit and the air valve In the control unit,
When the hydraulic pressure control unit is in an inoperative state and the air valve is self-diagnosis, the air valve is driven to drive the air valve while the hydraulic pressure control unit is disconnected from the air master cylinder and the wheel cylinder. An electronic control unit for a pneumatic-hydraulic conversion brake device, characterized in that it has means for performing self-diagnosis.

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