JPH1095321A - Brake device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a brake device which can perform stable brake control. SOLUTION: A brake device has a brake pedal 1 operated by a driver, a master cylinder 2 generating a brake fluid pressure in accordance with a step-in amount of the brake pedal 1, a fluid pressure sensor 3 detecting the brake fluid pressure to output a detection result as a master cylinder fluid pressure signal Sb, a controller 4 after obtaining a command current corresponding to a brake fluid pressure from the master cylinder fluid pressure signal Sb to overlap a triangular wave dither current with this command current output as a control current Ic, proportional control valves 111 to 114 open/close controlled by the control current Ic and wheel cylinders 151 to 154 giving brake force in accordance with a brake fluid pressure supplied from an accumulator 6 relating to each right/left rear wheel right/left front wheel. The controller 4 generates the control current Ic in which a control period is synchronized with a period of the dither current.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking device used for braking wheels of a vehicle.

[0002]

2. Description of the Related Art Conventionally, a vehicle is provided with a braking device for applying a braking force to four rotating wheels according to a running state. This braking device has a master cylinder having brake fluid inside and a brake pedal provided therein,
A hydraulic pressure sensor for detecting a brake hydraulic pressure in the master cylinder, four wheel cylinders respectively provided for four wheels, and connected to the four wheel cylinders and four pipe lines to generate a brake hydraulic pressure. It has a brake fluid pressure source, a proportional control valve having a solenoid interposed in each of the four pipelines, and a controller for controlling each part of the device.

In the above configuration, when the driver depresses the brake pedal, the brake fluid pressure in the master cylinder increases. This brake fluid pressure is detected by a fluid pressure sensor, and a brake fluid pressure signal corresponding to the brake fluid pressure is output from the fluid pressure sensor to the controller. Thus, the controller calculates a brake fluid pressure (hereinafter, referred to as a target fluid pressure) obtained from the brake fluid pressure signal for each control period Tc shown in FIG. 5B. Here, the target hydraulic pressure refers to a brake hydraulic pressure to be applied to a wheel cylinder, and is proportional to a braking force applied to a wheel.

Next, the controller superimposes a triangular-wave-shaped dither current Id shown in FIG. 5 (b) on a current having a magnitude corresponding to the calculated target hydraulic pressure, and uses this as a control current to control the proportional control valve. Output to the solenoid every control period Tc. Here, the dither current Id is a current that plays a role of imparting a slight vibration to the spool (valve) so as not to be fixed by the brake fluid pressure. In FIG. 5B, Ia is
This is the average current of the control current during the control period Tc.

When the above-described control current flows through the solenoid, an electromagnetic force acts on the spool, and as a result, the spool is moved. During this movement, the spool is moved while slightly vibrating due to the action of the dither current Id. Therefore, the spool moves smoothly without being fixed by the brake fluid pressure.

Thus, the proportional control valve is opened, the brake fluid pressure of the brake fluid pressure source is transmitted to the wheel cylinder via the pipeline and the proportional control valve, and a braking force acts on the wheels. I do.

[0007]

In the conventional braking device described above, the control period Tc and the cycle of the dither current Id are asynchronous with each other as shown in FIG. The magnitude of (control current) depends on the control period Tc.
Everything is different. That is, in the conventional braking device, the magnitude of the control current input to the solenoid of the proportional control valve varies every control period Tc, even though the depression amount of the brake pedal is constant. Fluctuates in the brake fluid pressure transmitted to the motor. Therefore, the conventional braking device has a problem that the braking control becomes unstable. The present invention has been made under such a background, and an object of the present invention is to provide a braking device capable of performing stable braking control.

[0008]

According to the present invention, a command current corresponding to the amount of depression of a brake pedal is obtained for each control cycle, and a triangular-wave-shaped dither current is superimposed on the command current and used as a control current. In a braking device having a control current generating means for outputting and a braking means for applying a braking force according to the control current to a wheel, a timer for resetting a time measurement result every time the command current is obtained; and A rising dither generating means for generating the dither current whose value gradually increases when the time counting result of the timer is 0, and when the time counting result of the timer is half of the time counting result immediately before the last reset, the value thereof is And a falling dither generating means for generating the dither current that gradually decreases.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of a braking device according to an embodiment of the present invention. In this figure,
1 is a brake pedal operated by the driver,
It is connected to the master cylinder 2 and movably provided in the direction of arrow A shown in FIG. The master cylinder 2 is
It has a brake fluid inside and generates a brake fluid pressure according to the amount of depression of the brake pedal 1. Reference numeral 3 denotes a hydraulic pressure sensor which detects a brake hydraulic pressure in the master cylinder 2 and outputs a detection result as a master cylinder hydraulic pressure signal Sb.

Reference numeral 4 denotes a controller for controlling each part of the apparatus. The controller 4 controls the brake hydraulic pressure to be applied to wheel cylinders 151 to 154, which will be described later, in accordance with the input master cylinder hydraulic pressure signal Sb according to the amount of depression of the brake pedal 1. After obtaining a current (hereinafter, referred to as a command current) corresponding to (the target hydraulic pressure), a triangular-wave-shaped dither current Id shown in FIG. 5A is superimposed on the command current, and this is used as a control current Ic. Output. Further, the controller 4 has a built-in elapsed time measurement timer for measuring time. The details of the operation of the controller 4 and the dither current Id and the control current Ic will be described later.

Reference numeral 5 denotes a brake fluid pressure generating source, which comprises an accumulator 6, a motor 7, a pump 8, a reservoir 9, and a fluid pressure sensor 10. The accumulator 6 accumulates brake fluid pressure. Motor 7
Is a motor drive signal SM supplied from the controller 4.
, And drives the pump 8.

The pump 8 is driven to rotate, so that
By discharging the brake fluid in the reservoir 9 to the accumulator 6, the brake fluid pressure in the accumulator 6 is increased. The reservoir 9 temporarily stores the brake fluid. The hydraulic pressure sensor 10 detects the brake hydraulic pressure in the accumulator 6 and outputs the detection result to the controller 4 as an accumulator hydraulic pressure signal Sa. The accumulator hydraulic pressure signal Sa is used for drive control of the motor 7.

Reference numeral 111 denotes a proportional control valve provided corresponding to the right rear wheel. The opening and closing of the valve is controlled by a control current Ic supplied from the controller 4, and an accumulator port, a reservoir port and a wheel cylinder port, which will be described later. have. The proportional control valve 111 has an accumulator port connected to the accumulator 6 via a pipe 12, a reservoir port connected to the reservoir 9 via a pipe 13, and a wheel cylinder port described later via a pipe 141. It is connected to the wheel cylinder 151.

Here, a detailed configuration of the above-described proportional control valve 111 will be described. In the proportional control valve 111,
Reference numeral 16 denotes a yoke, a cylindrical member 16a, a cylindrical member 16b disposed at a position coaxial with the cylindrical member 16a and having a diameter larger than that of the cylindrical member 16a;
A disk member 16c covering one end surface of each of the cylindrical members 16a and 16b, and a circular opening 16e is formed in the center of the disk member 16c.
And a disk member 16d that covers the other end surface of each of the first and second members 16b.

Reference numeral 17 denotes a solenoid made of a coil wound on the outer peripheral surface of the cylindrical member 16a of the yoke 16. The solenoid 17 has a control current I from the controller 4.
c is supplied. Reference numeral 18 denotes a moving member, and the yoke 16
Is provided movably in the direction of arrow B or C shown in FIG. This moving member 18
The cylindrical member 18a includes a cylindrical member 18a and a rod member 18b protruding from one end surface of the cylindrical member 18a.
Is the arrow B shown in the same figure from the circular opening 16e of the yoke 16.
It is provided so as to protrude in the direction. Reference numeral 19 denotes a spring, and the disc member 16c of the yoke 16 and the moving member 18
Is inserted between the other end surface of the cylindrical member 18a. This spring 19 urges the moving member 18 in the direction of arrow B shown in FIG.

Reference numeral 20 denotes a thick cylindrical member,
A circular opening 20a is formed on one end surface, and a reaction force port 20b smaller in diameter than the circular opening 20a is formed on the other end surface. One end surface of the cylindrical member 20 is liquid-tightly joined to the disk member 16d of the yoke 16. In addition, the cylindrical member 2
At 0, a cylinder chamber 20c is formed so as to communicate from the circular opening 20a to the reaction port 20b.

20d is an accumulator port,
The cylinder chamber 20c communicates with the outer peripheral surface of the cylindrical member 20. The end of the pipe 12 is connected to the accumulator port 20d. That is, brake fluid flows into the accumulator port 20 d from the accumulator 6 via the pipe 12.

A reservoir port 20e is formed adjacent to the accumulator port 20d at a predetermined interval.
The cylinder chamber 20c communicates with the outer peripheral surface of the cylindrical member 20. The end of the pipe 13 is connected to the reservoir port 20e. That is, the reservoir port 20
From e, the brake fluid in the cylinder chamber 20c flows out to the reservoir 9 via the pipe 13.

Reference numeral 20f denotes a communication path, which is a cylinder chamber 20c.
The port 20g and the port 20h formed at both ends of each are connected to each other. This communication path 20f also communicates with the reservoir port 20e. 2
Reference numeral 0i denotes a wheel cylinder port, which communicates from the cylinder chamber 20c between the accumulator port 20d and the reservoir port 20e to the outer peripheral surface of the cylindrical member 20. A pipe 141 is connected to the wheel cylinder port 20i.
The end of the branch pipe branched from the pipe 141 is connected to the reaction force port 20b.

Reference numeral 21 denotes a member provided in the cylinder chamber 20c in the vicinity of the reaction force port 20b, and has a cylindrical member having a communication hole formed in a central portion, and has the same inner diameter as the communication hole of the cylindrical member. The cylindrical member formed as described above is integrally formed. The communication hole 21a of this member 21 is
0b extends in the direction of arrow C shown in FIG.

Reference numeral 22 denotes a spool provided in the cylinder chamber 20c so as to reciprocate in the direction of the arrow B or C shown in the figure, and serves as a valve for opening and closing the accumulator port 20d or the reservoir port 20e.

The spool 22 includes a columnar member 22a having the same diameter as the cylinder chamber 20c, a columnar member 22b having the same shape as the columnar member 22a and arranged at a fixed interval, a columnar member 22a and a columnar member. Column member 22c connecting to 22b
And a substantially bar-shaped rod member 22d protruding from one end surface of the columnar member 22b.

The rod member 22d of the spool 22 is inserted into the communication hole 21a of the member 21, and the cylindrical member 22a
The rod member 18b of the moving member 18 is in contact with one end surface of the moving member 18. 23 is a cylindrical member 22 of the member 21 and the spool 22
b, and urges the spool 22 in the direction of arrow C shown in FIG.

The wheel cylinder 151 is provided corresponding to the right rear wheel.
11 is connected to the wheel cylinder port 20i.
The wheel cylinder 151 applies a braking force according to the applied brake fluid pressure to the right rear wheel.

Reference numeral 112 denotes a proportional control valve having the same configuration as the above-described proportional control valve 111, and is provided corresponding to the left rear wheel. In the proportional control valve 112, an accumulator 6 is connected to an accumulator port (not shown) through a pipe 12, and a pipe 13 is connected to a reservoir port (not shown).
The reservoirs 9 are connected to each other via the. The proportional control valve 112 has a control current Ic from the controller 4.
Is supplied. The wheel cylinder 152 is provided corresponding to the left rear wheel, and is connected to a wheel cylinder port (not shown) of the proportional control valve 112 via a pipe 142. The wheel cylinder 152 applies a braking force corresponding to the applied brake fluid pressure to the left rear wheel.

Reference numeral 113 denotes a proportional control valve provided corresponding to the right front wheel. In the proportional control valve 113, an accumulator port (not shown) is connected to an accumulator 6 via a pipe 12, and a reservoir port (not shown) is connected to a reservoir 9 via a pipe 13.
Further, a control current Ic is supplied from the controller 4 to the proportional control valve 113. The wheel cylinder 153 is
A wheel cylinder port (not shown) of the proportional control valve 113 is provided corresponding to the right front wheel via a pipe 143.
It is connected to the. The wheel cylinder 153 applies a braking force corresponding to the applied brake fluid pressure to the right front wheel.

Reference numeral 114 denotes a proportional control valve provided corresponding to the left front wheel. In the proportional control valve 114, an accumulator 6 is connected to an accumulator port (not shown) via a pipe 12, and a reservoir 9 is connected to a reservoir port (not shown) via a pipe 13.
Further, a control current Ic is supplied from the controller 4 to the proportional control valve 114. Wheel cylinder 154
A wheel cylinder port (not shown) of the proportional control valve 114 is provided via a pipe 144 so as to correspond to the left front wheel.
It is connected to the. The wheel cylinder 154 applies a braking force corresponding to the applied brake fluid pressure to the right front wheel.

Next, the operation of the braking device according to the above-described embodiment will be described with reference to FIG. FIG.
2 is a flowchart showing a processing procedure of a controller 4 shown in FIG. First, when the driver operates an ignition switch (not shown) during traveling of the vehicle, the controller 4 proceeds to step S1 of the flowchart shown in FIG. In step S1, the controller 4 resets the time interval for performing the braking control by itself, that is, the measurement value Tk of the elapsed time measurement timer for measuring the control cycle Tc to 0, and starts the time measurement. During the subsequent traveling of the vehicle, the controller 4 executes the processing from step S2 described below.

While the vehicle is running, the controller 4
, The master cylinder hydraulic pressure Sb based on the depression state of the brake pedal 1 is supplied from the hydraulic pressure sensor 3. Therefore, when the control cycle Tc for performing the braking control is reached, the controller 4 holds the measured value Tk of the elapsed time measurement timer at the time of the control cycle Tc in the memory in the controller 4 as the previous elapsed time Tk, As shown in step S2, the master cylinder hydraulic pressure signal Sb output from the hydraulic pressure sensor 3 at that time is read, and based on the read master cylinder hydraulic pressure signal Sb, the brake fluid to be applied to the wheel cylinders 151 to 154 is read. After obtaining the pressure (hereinafter referred to as a target hydraulic pressure), a current having a magnitude corresponding to the target hydraulic pressure (hereinafter referred to as a command current) is obtained.

Next, the controller 4 determines in step S3
As shown in FIG. 5, a dither current Id (rising dither Idu) shown in FIG. 5A is superimposed on the obtained command current, and is output to the proportional control valves 111 to 114 as a control current Ic. Proceed to. Here, the rising dither Idu means a dither current Id whose value gradually increases with time.

Then, the controller 4 determines in step S3
As a result, the output of the control current Ic to the proportional control valves 111 to 114 is started, and at the same time, in step S4, the measured value Tk of the elapsed time measuring timer is set to 0, and the counting is started again.

On the other hand, the controller 4 determines in step S5 that the last elapsed time T
The dither switching time Tk / 2 is calculated from k, and the dither switching time Tk / 2 is set in an internal memory as a change timing of the dither current Id. Then, in step S6, the controller 4 determines, for each wheel, an output of a wheel speed sensor (not shown) provided for each wheel for other processing necessary for the braking control (for example, for anti-skid brake control or the like). And the like to calculate the wheel rotation speed)
After the execution processing, the processing after step S2 is repeated again.

Here, during execution of the other processing in step S6, the controller 4 executes the dither switching processing as shown in FIG. 2 in synchronization with the progress of the measurement of the measurement value Tk by the elapsed time measurement timer. Do. That is, as shown in step S61, the controller 4 sets the elapsed time Tk measured by the elapsed time measurement timer to the dither switching set in step S5, as shown in step S61, every time the measurement of the measurement value Tk by the elapsed time measurement timer progresses. Time Tk / 2
To see if it matches. As a result of this comparison, if the elapsed time Tk does not match the dither switching time Tk / 2, the controller 4 returns to the above-described other processing in step S6 and executes the continuation of the other processing. Is equal to the dither switching time Tk / 2, as shown in step S62,
In 3, further superimposition of the dither current Id (rising dither Idu) is stopped with respect to the control current Ic in which Id (rising dither Idu) is superimposed on the command current, and the dither current Id (falling dither Idd) is replaced with a new one. Superimposed on

Each of the above processes performed by the controller 4 is shown in FIG.
To explain with reference to (a), assuming that a new control cycle Tc is reached at time t0, the controller 4 performs the processing of the above-described steps S2 to S5, and
The value Tk measured by the elapsed time measurement timer at 0 is held as the previous elapsed time Tk. On the other hand, controller 4
Calculates a command current corresponding to the target hydraulic pressure applied to the wheel cylinders 151 to 154 from the currently input master cylinder hydraulic pressure signal Sb. Next, the controller 4
Is the dither current Id (rising dither Idu)
Are superimposed and output as control currents Ic to the proportional control valves 111 to 114 shown in FIG. 1, respectively, and time measurement of this new control cycle Tc is started by the elapsed time measurement timer. As a result, the proportional control valves 111 to 114 have the time t
After 0, a current on which the dither current Id (rising dither Idu) is superimposed and whose value gradually increases with time is supplied as the control current Ic.

Then, while the dither current Id (rising dither Idu) is superimposed and the control current Ic whose value gradually increases with the passage of time is supplied to the proportional control valves 111 to 114, the controller 4 outputs the control current Ic. Performs the other processes in step S6 described above. However, when the elapsed time Tk reaches 1/2 of the previous elapsed time Tk (that is, the previous control cycle Tc) at time t1 shown in FIG. I
du) is stopped and the dither current Id is
(Falling dither Idd) is newly superimposed, and the control current I
As c, the signals are output to the proportional control valves 111 to 114 shown in FIG.

After that, at time t2 shown in FIG. 5A, the controller 4 completes the other processing in step S6, and shifts to the next control cycle Tc. In FIG. 5A, the case where the processing time of the other processing in step S6 by the controller 4 for each control cycle Tc is the same and the time of each control cycle Tc is equal is considered. The current Ia has the same value in each control cycle Tc.

Here, the operation of the proportional control valves 111 to 114 when the driver operates the brake pedal 1 shown in FIG. 1 while the vehicle is running will be described. When the driver depresses the brake pedal 1 shown in FIG. 1 while the vehicle is running, a control current Ic corresponding to the depression amount of the brake pedal 1 is applied to the proportional control valve 111.
, A magnetic field is generated inside the solenoid 17 in the direction of arrow B shown in FIG. The magnitude of this magnetic field changes according to the dither current Id shown in FIG. Thereby, the moving member 18 moves while slightly vibrating in the direction of arrow B shown in FIG. This micro-vibration is
This is due to the influence of the dither current Id.

Then, in conjunction with the movement of the moving member 18,
The spool 22 moves in the direction of arrow B shown in FIG. When the moving member 18 moves by a distance corresponding to the magnitude of the control current Ic against the spring 23, the spool 22 moves the cylindrical member 22a to the reservoir port 20e.
Is completely closed, and the column member 22b moves to a position where it closes a part of the accumulator port 20d or completely opens the entire accumulator port 20d. Here, when the cylindrical member 22b of the spool 22 blocks a part of the accumulator port 20d, the closing amount corresponds to the magnitude of the control current Ic.

Thus, from the accumulator 6, the pipe 12 → the accumulator port 20d → the cylinder chamber 20c
→ Wheel cylinder port 20i → Passage 141, reaction force port 20b and wheel cylinder 151
To each other. At this time, the brake fluid pressure of the wheel cylinder 151 is also supplied to the reaction force port 20b via the branch pipe of the pipe 141, so that the brake fluid pressure of the wheel cylinder 151 acts on the rod member 22d of the spool 22. Will be done. As a result, when the brake fluid pressure of the wheel cylinder 151 rises to the target fluid pressure, the spool 22 exerts a pressing force based on the brake fluid pressure of the wheel cylinder 151 acting on the rod member 22d in the direction of arrow C in FIG. The urging force of the spring 23 acts. When the pressing force and the urging force are balanced with the pressing force in the direction of arrow B in FIG. 1 by the control current Ic, the cylindrical member 22a of the spool 22 closes the reservoir port 22e, and the cylindrical member 22b of the spool 22 is closed. The vehicle stops at the position that closes the accumulator port 20d, and a braking force corresponding to the target hydraulic pressure is applied to the right wheel.

In the same manner as in the above-described operation, the accumulator 6 passes through the route of the pipe 12 → the proportional control valve 112 → the pipe 142 to the wheel cylinder 152 and the pipe 12 →
Via a path of proportional control valve 113 → pipe 143 to wheel cylinder 153, and pipe 12 → proportional control valve 114 →
The brake fluid pressure is transmitted to the wheel cylinders 154 via a pipe 144. Accordingly, the braking force is applied to the left rear wheel, the right front wheel, and the left front wheel, so that the traveling speed of the vehicle is reduced.

Now, when the driver's foot is released from the brake pedal 1, the brake fluid pressure in the master cylinder 2 drops sharply, and the master cylinder fluid pressure output from the fluid pressure sensor 3 is reduced. The value of the signal Sb drops sharply. Thus, the controller 4 determines a target hydraulic pressure according to the master cylinder hydraulic pressure signal Sb at this time.
This target hydraulic pressure is set to a value that sets the brake hydraulic pressure applied to the wheel cylinders 151 to 154 to 0 MPa. Next, the controller 4 superimposes the dither current Id on the command current corresponding to the obtained target hydraulic pressure in the same manner as in the above-described operation, and sets this as the control current Ic, thereby setting the proportional control valves 111 to
Output to 114 solenoids. Here, the control current Ic that is now being output is smaller than the control current Ic that has been output during braking.

The solenoid 1 of the proportional control valve 11 1
When the control current Ic is input to the block 7, the magnitude of the magnetic field generated in the direction of the arrow B shown in FIG. Thereby, the spool 22 and the moving member 1
8 are returned in the direction of arrow C shown in FIG. Then, the spool 22 and the moving member 18
Is held at a position where the elastic force of the spring 23, the elastic force of the spring 19, and the electromagnetic force of the solenoid 17 only by the dither current Id are balanced. At this time, the spool 22
Is held at a position where the cylindrical member 22b completely blocks the accumulator port 20d and the cylindrical member 22a completely opens the reservoir port 20e.

As a result, the brake fluid in the wheel cylinder 15 and the pipe 141
0i → cylinder chamber 20c → reservoir port 20e → piping 1
After returning to the reservoir 9 via the route 3. As a result, the braking force on the right rear wheel is released. Similarly, the braking force on the rear left wheel, the front right wheel, and the front left wheel is released.

Next, another operation of the braking device according to the above-described embodiment will be described with reference to FIGS. 4 (a) and 4 (b). In the operation described below, the processing in step S6 shown in FIG.
This is a case where K is extended and the control cycle Tc changes. FIG.
In (b), from time t0 to time t4 shown in the figure, control in the case where the elapsed time TK, that is, the control cycle Tc is equal, is performed in the same manner as the operation described above. That is, the waveform of the dither current Id from time t0 to time t4 is a shaped triangular wave.

Here, at time t4 shown in FIG. 4B, the controller 4 proceeds to step S4 shown in FIG. 2 and outputs the control current Ic on which the dither current Id (rising dither Idu) is superimposed. Proceeding to step S5, elapsed time TK
After the value of is set to 0, the process proceeds to step S5. Step S5
Then, the controller 4 determines that one half of the previous elapsed time TK
Is set as the dither switching time.

Then, when the set dither switching time at time t5 shown in FIG.
The result of the determination in step S61 is made "YES", and the routine proceeds to step S62. In this case, since the previous elapsed time TK in step S5 is equal to the control cycle Tc, FIG.
The output time of the rising dither Idu (time t4 to time t5) shown in (b) is the output time of the previous rising dither Idu (time t2).
To time t3).

In step S6 shown in FIG. 2, the controller 4 executes other processes and executes step S6.
The dither current Id (falling dither Idd) is output at time t5 shown in FIG. Here, the processing time of step S6 (from time t5 to
Assuming that the time t6) is longer than the normal processing time (time t3 to time t4), the controller 4 proceeds to step S6.
The process returns to step S2 at the time t6 when the processing of the above is completed. That is, the output time of the falling dither Idd (time t5 to time t6) shown in FIG. 4B is longer than the output time of the falling dither Idd (time t3 to time t4) of the previous control cycle Tc.

Next, in step S2 (time t6), the measured value Tk (time t4 to time t6) of the elapsed time measurement timer is set as the previous elapsed time Tk in the controller 4 in the same manner as the above-described operation. After reading the master cylinder hydraulic pressure signal Sb, the master cylinder hydraulic pressure signal Sb output from the hydraulic pressure sensor 3 is read.
The command current is obtained based on

Next, the controller 4 determines in step S3
As shown in FIG. 5, a dither current Id (rising dither Idu) shown in FIG. 5B is superimposed on the obtained command current, and this is output to the proportional control valves 111 to 114 as a control current Ic. Then, the measurement value Tk of the elapsed time measurement timer is set to 0, and the time measurement is started again.

On the other hand, the controller 4 determines in step S5 that the last elapsed time T
The dither switching time Tk / 2 is calculated from k (time t4 to time t6), and the dither switching time Tk / 2 is set in the internal memory as the change timing of the dither current Id. And
In step S6, the controller 4 performs other processing necessary for the braking control, and as shown in step S61, the elapsed time Tk measured by the elapsed time measurement timer is set to the dither switching time set in step S5. A comparison is made to see if they match Tk / 2. Then, at time t7, if the result of the determination in step S61 is "YES", the controller 4 superimposes the dither current Id (falling dither Idd) on the command current. Less than,
Similarly to the operation described above, the controller 4 sets the time t8
Then, the process returns to step S2, and the above-described process is repeated. As a result, a dither current Id having a waveform as shown in FIG. 4B is generated.

Next, in step S5 shown in FIG.
The effect of setting the dither switching time to the dither switching time Tk / 2 will be described with reference to FIGS. 4A and 4B. FIG. 4A shows the setting of the dither switching time in step S5 shown in FIG.
FIG. 9 is a waveform diagram showing a waveform of a dither current Id when the number is 2. As can be seen by comparing FIGS. 4A and 4B, the waveform of the dither current Id shown in FIG. 4B has less variation than the waveform of the dither current Id shown in FIG. Therefore, according to the braking device according to the embodiment of the present invention, the fluctuation of the average current Ia shown in FIG.
The variation of the average current Ia shown in FIG.

As described above, according to the braking device according to the embodiment of the present invention, the period of the dither current Id and the control period Tc are synchronized, so that stable braking control can be performed. The effect is obtained.

As described above, one embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and a design change or the like may be made without departing from the gist of the present invention. The present invention is also included in the present invention. For example, in the braking device according to the above-described embodiment, an example has been described in which the control cycle Tc is synchronized with one cycle of the dither current Id as shown in FIG.
Without being limited to this, synchronization may be performed by the method shown in FIGS. That is, FIG. 3A shows that the control cycle Tc and 1 / (dither current Id) are different.
FIG. 3B illustrates an example in which synchronization is performed so that two periods coincide with each other. FIG. 3B illustrates an example in which synchronization is performed so that two periods of the control period Tc and the dither current Id coincide with each other. It was done.

[0054]

According to the present invention, the rising dither generating means and the falling dither generating means synchronize the dither current and the control current, so that the braking force of the braking means is stabilized. Therefore, according to the present invention, an effect is obtained that stable braking control can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a braking device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a processing procedure of a controller 4 shown in FIG.

FIG. 3 is a waveform chart showing waveforms of a dither current Id obtained by a modification of the braking device according to the same embodiment.

FIG. 4 is a waveform diagram illustrating an effect of the braking device according to the same embodiment.

FIG. 5 is a waveform chart showing waveforms of a dither current Id and the like used in the braking device according to the related art and one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake pedal 3 Hydraulic pressure sensor 4 Controller 111-114 Proportional control valve 151-154 Wheel cylinder Ic Control current Id Dither current

Claims (1)

[Claims] A control current generating means for obtaining a command current corresponding to a depression amount of a brake pedal for each control cycle, superimposing a triangular-wave-shaped dither current on the command current, and outputting this as a control current; A braking device having braking means for applying a braking force according to the control current to a wheel, wherein a timer resetting a timed result every time the command current is obtained; and a timed result of the timer being zero. Rising dither generating means for generating the dither current whose value gradually increases, and when the timed result of the timer is half of the timed result immediately before the last reset, the value of the dither current whose value gradually decreases And a descending dither generating means for generating.