JP2000062591A - Electric control device for brake of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To apply proper brake on wheels in a vehicle brake by properly controlling an electric actuator. SOLUTION: Pressure to press a pad against a disc is detected by a pressure sensor, a detecting pressure Fm is corrected by a correction value (k) and set as a correction pressure Fm' at a step 112. Based on a correction pressure Fm', operation of an electric motor is controlled at steps 114-120. The correction value (k) is decided based on a most proper pressure considered as the pressure, actually pressing the pad against the disc, of a lower limit pressure or an upper limit pressure calculated based on a displacement amount from a position wherein a pad makes contact with a disc and a pressure calculated based on an amount of a current flowing through an electric motor to deviate the pad from the disc. Decision of the correction value (k) is executed even when the detecting pressure Fm is abnormal but when the detecting pressure Fm is below a given pressure, the decision of the correction value (k) is prohibited.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric control device for a vehicle brake for braking a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a device of this type, as shown in, for example, Japanese Patent Application Laid-Open No. 63-242764, a rotating body that rotates integrally with a wheel and a rotating body are provided so as to face the rotating body. It is applied to a vehicle brake equipped with a friction member that brakes the rotation of a wheel by being pressed against the same rotating body and an electric actuator that is electrically controlled to displace the friction member and press it against the rotating body. There is a system in which the pressure received from the rotating body is detected by a reaction force sensor, and the electric actuator is controlled based on the detected pressure to brake the wheels.

[0003]

However, in the above-mentioned conventional device, since the electric actuator is controlled by directly using the pressure detected by the reaction force sensor, the electric actuator is appropriate due to an error in detection by the reaction force sensor. There is a problem that the wheels are not properly controlled and the wheels are not properly braked.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to address the above problems, and an object thereof is to provide an electric control device for a vehicle brake that appropriately controls an electric actuator to properly brake wheels. Especially.

The first structural feature of the present invention for achieving the above object is applied to the vehicle brake, and a pressure sensor for detecting the pressure at which the friction member is pressed against the rotating body and a pressure sensor for detecting the pressure are detected. In an electric control device for a vehicle brake, which includes an actuator control unit that controls an electric actuator based on the applied pressure, a displacement amount detection unit that detects a displacement amount of a friction member and a displacement amount detection unit detect the displacement amount. The correction value is determined based on the displacement amount, and the correction value is used to correct the pressure detected by the pressure sensor. According to this, the pressure detected by the pressure sensor is corrected by the correction unit based on the displacement amount detected by the displacement amount detection unit. In this case, the displacement amount is also a value corresponding to the pressure with which the friction member is pressed against the rotating body, so that the pressure detected by the pressure sensor accurately represents the actual pressure with which the friction member is pressed against the rotating body. become. Then, the actuator control means controls the electric actuator based on the corrected pressure. Therefore, the electric actuator is properly controlled and the wheels are properly braked.

The second structural feature of the present invention is applied to a vehicle brake that employs an electric actuator that displaces a friction member in response to the supply of an electric current and presses it against a rotating body, as the electric actuator. An electric control device for a vehicle brake, comprising a pressure sensor and an actuator control means for controlling a current supplied to an electric actuator based on a pressure detected by the pressure sensor, in which a current measurement for measuring a current flowing through the electric actuator Means and correction means for determining a correction value based on the amount of current measured by the current measuring means and correcting the pressure detected by the pressure sensor using the correction value. According to this, the pressure detected by the pressure sensor is corrected by the correction unit based on the amount of current measured by the current measuring unit. In this case, the amount of current is also a value corresponding to the pressure with which the friction member is pressed against the rotating body, so that the pressure detected by the pressure sensor is
The friction member accurately represents the actual pressure applied to the rotating body. Then, the actuator control means controls the electric actuator based on the corrected pressure. Therefore, the electric actuator is properly controlled and the wheels are properly braked.

The third structural feature of the present invention is applied to a vehicle brake that employs an electric actuator similar to that of the second structure, and is equipped with the pressure sensor and actuator control means. An electric control device for calculating a lower limit pressure and an upper limit pressure that are considered as a pressure at which the friction member is pressed against the rotating body, based on the displacement amount detecting means and the displacement amount detected by the displacement amount detecting means. Detected by the pressure calculation means, the current measurement means, the second pressure calculation means for calculating the pressure at which the friction member is pressed against the rotating body based on the magnitude of the current measured by the current measurement means, and the pressure sensor. When the pressure calculated by the second pressure calculation means is less than or equal to the lower limit pressure calculated by the first pressure calculation means, the correction value for the pressure If the pressure calculated by the second pressure calculation means is higher than the lower limit pressure calculated by the first pressure calculation means and smaller than the upper limit pressure, the pressure is calculated by the second pressure calculation means. If the pressure calculated by the second pressure calculating means is equal to or higher than the upper limit pressure calculated by the first pressure calculating means, the pressure is determined using the same upper limit pressure, and the same correction value is used. And a correction means for correcting the pressure detected by the pressure sensor.

In the electric control device for a vehicle brake having the above characteristics, the upper limit pressure and the lower limit pressure calculated by the first pressure calculating means based on the displacement amount detected by the displacement amount detecting means, and the current measuring means. Of the pressures calculated by the second pressure calculation means based on the amount of current measured by, the pressure sensor detects the most appropriate pressure that is considered as the pressure at which the friction member is actually pressed against the rotating body. The applied pressure is corrected by the correction means. This allows the pressure detected by the pressure sensor to accurately represent the actual pressure with which the friction member is pressed against the rotating body. Then, the actuator control means controls the electric actuator based on the corrected pressure. Therefore, the electric actuator is properly controlled and the wheels are properly braked.

A fourth structural feature of the present invention is that in the electric control device for a vehicle brake having the second or third structural feature, the friction member is brought into contact with the rotating body. A contact detecting means for detecting and a current storing means for storing the amount of current flowing through the electric actuator based on the measurement by the current measuring means when the contact detecting means detects the contact of the friction member with the rotating body are provided. The correction value for the pressure detected by the pressure sensor is determined based on the current amount obtained by subtracting the current amount stored in the current storage unit from the current amount measured by the current measuring unit. It is in.

In the electric control device for a vehicle brake having the above characteristics, the pressure sensor is based on the current amount obtained by subtracting the current amount stored in the current storage device from the current amount measured by the current measuring device. The pressure detected by is corrected. In this case, the amount of current stored in the current storage means is the amount of current flowing in the electric actuator when the contact detection means detects the contact of the friction member with the rotating body. It is the amount of current required to start pressing the member against the rotating body. Therefore, the amount of current obtained by subtracting the amount of current stored in the current storage unit from the amount of current measured by the current measuring unit is converted into the pressure that actually presses the friction member against the rotating body among the current flowing through the electric actuator. Accurately represents the amount of current that is applied. This allows the pressure detected by the pressure sensor to more accurately represent the actual pressure with which the friction member is pressed against the rotating body. Then, based on the corrected pressure, the actuator control unit controls the electric actuator. Therefore, the electric actuator is controlled more appropriately and the wheels are more properly braked.

Further, in the electric control device for a vehicle brake having each of the above characteristics, it is preferable that the correction value for the pressure detected by the pressure sensor is determined every predetermined time. Further, an abnormality detecting means for detecting an abnormality in the pressure detected by the pressure sensor is provided, and when the abnormality is detected by the abnormality detecting means, a correction value for the pressure detected by the pressure sensor is determined. You may

Further, another structural feature of the present invention is that the determination of the correction value for the pressure detected by the pressure sensor is performed in the electric control device for the vehicle brake having the above features. This is to prohibit when the pressure detected by the pressure sensor is below a predetermined pressure. According to this, it is possible to avoid determining the correction value based on each detection value in a state where the pressure with which the friction member is pressed against the rotating body is small, that is, in a state where the ratio of the error of each detection value is large, The correction value is always kept proper. Therefore, the pressure detected by the pressure sensor always accurately represents the actual pressure at which the friction member is pressed against the rotating body, so that the electric actuator is always properly controlled and the wheels are always properly braked.

Further, another structural feature of the present invention is that the determination of the correction value for the pressure detected by the pressure sensor is performed in the electric control device for the vehicle brake having the above features. This is to permit only when the pressure detected by the pressure sensor is kept constant for a predetermined time. According to this, it is possible to avoid that the correction value is determined based on each detection value in a state where the position of the friction member with respect to the rotating body is not fixed, that is, each detection value becomes unstable. Is always properly maintained. Therefore, the pressure detected by the pressure sensor always accurately represents the actual pressure at which the friction member is pressed against the rotating body, so that the electric actuator is always properly controlled and the wheels are always properly braked.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram schematically showing an entire vehicle brake according to the same embodiment. This vehicle is provided with disc type brakes 10 at front, rear, left and right wheel positions (only one is shown).

As shown in detail in FIG. 2, each brake 10 has a disk 11 as a rotating body which rotates integrally with a wheel around an axis line in the left-right direction in the figure, and a disk 11 on both sides of the disk 11, respectively. Pads 12a and 12b as a pair of friction members arranged facing each other, and the disk 1
1 and a caliper 13 accommodating the pads 12a and 12b. The caliper 13 is assembled to the vehicle body (not shown) so as to be displaceable in the axial direction of the disc 11, and the pad 1 on the outer side (right side in the figure) of the disc 11 is attached.
2a is fixed by a back metal 12a1 of the pad 12a. An electric motor 20 as an electric actuator is accommodated in the caliper 13.

The electric motor 20 has a stator 21. The stator 21 is formed in a ring shape by arranging a plurality of coils to which currents are respectively provided side by side in the circumferential direction.
It is non-rotatably fixed on the inner peripheral surface of 3. Stator 2
A rotor 22 formed in a cylindrical shape is coaxially arranged inside the stator 1. A plurality of permanent magnets 22a are fixed on the outer peripheral surface of the rotor 22 along the circumferential direction, and the rotor 22 rotates around the axis of the stator 21 in response to the supply of current to each coil of the stator 21. It is designed to rotate. A cylindrical nut 23 is coaxially fixed on the outer peripheral surface of the inner peripheral surface of the rotor 22. The nut 23 is supported on the inner peripheral surface of the caliper 13 so as to be immovable in the axial direction and rotatable about the axial line. When the rotor 22 rotates, the nut 23 rotates integrally with the caliper 13 and the stator 21. . Inside the nut 23, a cylindrical shaft 24 is provided.
It is arranged coaxially with. Threads are formed on the inner peripheral surface of the nut 23 and the outer peripheral surface of the shaft 24. The threads on the respective surfaces are parallel to the nut 23 and the shaft 24 that are arranged at equal intervals in the circumferential direction. Multiple screw rollers 2
5 is screwed. Each screw roller 25 has the above nut 2
According to the rotation of 3, the shaft 24 is displaced in the axial direction while rotating around each axis.

When the shaft 24 is displaced in the direction projecting from the nut 23 (rightward in the drawing), first, at the tip of the shaft 24, the backing metal 12b of the pad 12b inside the disk 11 is formed.
Abut 1. Then, after the contact, the pad 12b is integrally displaced with the shaft 24 so as to contact the inner surface of the disk 11 and press it. At this time, the reaction force causes the caliper 13 to move toward the shaft 24 against the disk 11.
The pad 12a on the outer side of the disk 11 is pressed against the outer surface of the disk 11 by displacing it in the direction opposite to the displacement direction. As a result, the electric motor 20 displaces the pads 12a and 12b and presses them on both sides of the disk 11 in accordance with the supply of current to the coils of the stator 11. At this time, the disk 11 and each pad 12a, 1
Due to the friction with 2b, the rotation of the disk 11 is braked and the rotation of the wheels is braked.

The electric motor 20 includes a rotary encoder 26,
A pressure sensor 27 and a stroke switch 28 are also provided. The rotary encoder 26 includes a plurality of magnets 26a that are arranged side by side in the rotor 22 in the circumferential direction, and a plurality of Hall elements 26b that are arranged in the circumferential direction in the caliper 13 facing the magnets 26a. As the rotor 22 rotates with respect to the caliper 13, a magnet 26 is provided for each Hall element 26b.
The approach of a is detected and a signal representing each detection is output. The pressure sensor 27 is composed of a load cell such as a piezoelectric element and a strain gauge, and is arranged at the tip of the shaft 24. The pressure sensor 27 detects the pressure applied to the pad 12b by the shaft 24 so that the pads 12a and 12b move to the disk 11. The pressure to be pressed is detected and a signal representing the detected pressure Fm is output.

The stroke switch 28 is for the shaft 24.
A pair of electrodes 28a and 28b exposed on the contact surface with the pad 12b. Both electrodes 28a, 28
b is insulated from each other when the shaft 24 is separated from the back metal 12b1 of the pad 12b, and when the shaft 24 is in contact with the back metal 12b1 of the pad 12b, that is, when the pad 12b starts to be pressed against the disk 11, Conduction is provided through the back metal 12b1. As a result, the stroke switch 28 is turned on when the pad 12b is in contact with the disc 11 and is turned off when the pad 12b is separated from the disc 11, and outputs a signal indicating the on / off state. It is like this.

The vehicle also includes a microcomputer 30. The microcomputer 30 executes the programs corresponding to the flowcharts of FIGS.
A control signal is output to each drive circuit 31 for operating the electric motor 20 of 0, and each electric motor 20 is drive-controlled to independently control the braking force generated by each brake 10. The microcomputer 30 is also connected to the rotary encoder 26 via a converter 32. The converter 32 converts a detection signal for each Hall element 26a of the rotary encoder 26 into a signal representing a displacement amount dS of the pad 12b with respect to the disk 11 and outputs the signal to the microcomputer. The converter 32 is also connected to the drive circuit 31, and the detection signal from the rotary encoder 26 is converted into a signal representing the relative position of the rotor 22 with respect to the stator 21 by the converter 32, and then the drive circuit. Three
It is also input to 1 and used for controlling the operation of the electric motor 20 by the drive circuit 31.

The microcomputer 30 is connected to the pressure sensor 27 and the stroke switch 28, and also has an ammeter 33 and a pedal stroke sensor 3.
It is also connected to 4. The ammeter 33 is provided in a current supply path from the drive circuit 31 to the electric motor 20, measures the electric current flowing through the electric motor 20, and outputs a signal representing the measured current amount i to the microcomputer 30. The pedal stroke sensor 34 is attached to a brake pedal BP operated by a user, detects a stepping operation amount of the brake pedal BP, and outputs a signal representing the detected operation amount to the microcomputer 30. Further, the microcomputer 30 has a timer 30a built therein. The timer 30a generates a timer interrupt signal every predetermined short time and causes the microcomputer 30 to execute the timer interrupt program of FIG.

Next, the operation of the embodiment configured as described above will be described with reference to the flow charts of FIGS. The microcomputer 30 starts the execution of the main program in step 100 of FIG. 3 in response to the turning-on operation of an ignition switch (not shown), and thereafter, step 102-
The circulation process consisting of 122 is repeatedly executed. In this case, first, at step 102, the brake pedal BP
An output signal from the pedal stroke sensor 34, which indicates the amount of depression operation of the pedal, is input, and in step 104, the target pressure F
To calculate. The target pressure F is calculated according to a predetermined calculation method as an ideal value of the pressure that presses the pads 12a and 12b against the disk 11, based on the depression operation amount of the brake pedal BP input in step 102 and the like. is there.

After the calculation of the target pressure F, the microcomputer 30 inputs a signal indicating the pressure Fm at which the pads 12a and 12b detected by the pressure sensor 27 are pressed against the disk 11 in step 106. The processing of steps 108 and 110 will be described later. In step 112, the detected pressure Fm input in step 106 is multiplied by the correction value k to correct the detected pressure Fm to obtain the corrected pressure Fm '. This correction value k
Is initially set to the value "1" by an initial setting (not shown), which will be described in detail later.

In step 114, the correction pressure Fm 'and the target pressure F are compared and determined. Then, based on the determination result in step 114, the correction pressure F
If m'is smaller than the target pressure F, step 11
At 6, the electric current supplied to the electric motor 20 is increased to displace the pads 12a, 12b in the direction of pressing the disk 11 to increase the pressure of the pressing. Correction pressure Fm '
Is equal to the target pressure F, in step 118, the amount of current supplied to the electric motor 20 is maintained to maintain the positions of the pads 12a and 12b with respect to the disk 11, and the pads 12a and 12b are connected to the disk. Make sure to maintain the pressure to press 11. If the corrected pressure Fm 'is larger than the target pressure F, in step 120,
The current supplied to the electric motor 20 is reduced. This allows
The pads 12a and 12b are displaced in the direction away from the disk 11 by the reaction force from the disk 11,
The pressure with which 2a 12b presses the disk 11 is reduced.

Step 122 is a process for updating the correction value k, which will be described later in detail. The microcomputer 30 controls the operation of the electric motor 20 based on the pressure Fm detected by the pressure sensor and the pressure for pressing the pads 12a and 12b against the disk 11 by repeatedly executing the circulation processing of steps 102 to 122 as described above. Then, the braking force on the disk 11 and the wheels is controlled.

Next, the correction value updating process in step 122 will be described. When starting the execution of the same process in step 200 of FIG. 4, the microcomputer 30 first starts in step 202 the stroke switch 2
By inputting the output signal of No. 8 and determining whether the voltage of the signal is proper, it is determined whether the switch 28 is normal. Then, if the switch 28 is normal, based on the determination of "YES" in step 204, it is determined in step 210 whether the switch 28 is in the ON state. At this time, if the shaft 24 is separated from the back metal 12b1 of the pad 12b and the switch 28 is in the off state, the microcomputer 30 makes a program step 206 based on the judgment of "NO".
Then, the cumulative displacement amount S is set to the value “0”. The cumulative displacement amount S is for representing the displacement amount from the position where the pad 12b is in contact with the disk 11. After setting the cumulative displacement amount S, in step 208, the output signal from the ammeter indicating the amount of current i flowing through the electric motor 20 is input.

Next, the microcomputer 30 determines in step 210 whether the accumulated displacement amount S is larger than the value "0". Since the cumulative displacement amount S has been set to the value "0" by the processing of step 206, the program advances to step 212 based on the determination of "NO" in step 210. Step 212
, The current amount i input in the above step 208
Is set as the reactive current amount a. The reactive current amount a is because the electric motor 20 starts to displace the shaft 24 by generating a driving force greater than a physical resistance force such as the rotation resistance force of the roller screw 25, in other words, the pad 12b is pressed against the disk 11. This is to represent the amount of current required to start. After the above setting, the microcomputer 30
Ends the correction value updating process at step 246.

As described above, during the circulation processing of steps 102 to 122 in the main program of FIG. 3, while the shaft 24 is separated from the pad 12b and the pad 12b is separated from the disk 11, the correction value of step 122 is set. In the update process, steps 200 to 21 in FIG.
The processing of 2,246 is repeatedly executed. At this time, the accumulated displacement amount S is maintained at the value “0”, and the reactive current amount a is repeatedly updated and set to the amount of current flowing through the electric motor 20.

During this repeated execution, the process of step 116 of FIG. 3 causes the shaft 24 to be displaced in the direction in which it projects from the nut 23 and contact the pad 12b. When the pad 12b contacts the disk 11, the stroke switch 28 This is detected by switching from the off state to the on state. Accordingly, thereafter, the microcomputer 30 causes the “YE” in step 204 of FIG.
Based on the determination of "S", the processes of steps 214 to 216 are executed instead of the process of step 206. In step 214, the output signal from the converter 32 representing the displacement amount dS of the pad 12b with respect to the disk 11 is input. In step 215, the differential displacement amount dS ′ is calculated. The difference displacement amount dS ′ represents the difference between the displacement amount dS input in step 214 and the previous input. In step 216, the calculated differential displacement amount dS ′ is added to the cumulative displacement amount S. As a result, the cumulative displacement amount S thereafter represents the displacement amount from the position where the pad 12b is in contact with the disk 11,
In step 210, the microcomputer 30 returns "YE
S ”is determined and the program proceeds to step 218 and thereafter. Further, at this time, since the update setting of the reactive current amount a in step 212 is not executed, the amount of current flowing through the electric motor 20 is stored as the reactive current amount a based on the measurement by the ammeter. .

In steps 218 and 220, the lower limit pressure Fsmin and the upper limit pressure Fsmax, which are considered as the pressure with which the pad 12b is pressed against the disk 11, are calculated based on the cumulative displacement amount S. These calculation processes will be described. Generally, the pressure with which the pad 12b is pressed against the disk 11 is the accumulated displacement amount S, that is, the pad 12b.
It is proportional to the amount of displacement from the position of b contacting the disc (see FIG. 6). In this case, the proportional constant, that is, the pressure FS corresponding to a certain cumulative displacement amount S, gradually increases as the number of times the pad 12b is used increases. The microcomputer 30 stores in advance the proportional constant b1 when the pad 12b is used the least number of times and the proportional constant b2 when the pad 12b is used the most number of times, and the product of the cumulative displacement amount S and the proportional constant b1. (B1 · S) is calculated as the lower limit pressure Fsmin, and the product (b2 · S) of the cumulative displacement amount S and the proportional constant b2 is calculated as the upper limit pressure Fsmax.

In step 222, the pressure with which the pad 12b is pressed against the disk 11 is calculated based on the current amount i. This calculation process will be described. Generally, the pressure with which the pad 12b is pressed against the disk 11 is also proportional to the amount of current i flowing through the electric motor 20 (see FIG. 7). However, of the same current amount i, the amount of current flowing through the electric motor 20 when the shaft 24 abuts on the pad 12b, that is, the reactive current amount a is as described above.
Since 0 is the amount of current required to start displacing the shaft 24 and start pressing the pad 12b against the disk 11, it is not converted into the pressure for pressing the pad 12b against the disk 11. In consideration of this, the microcomputer 30 calculates the product of the current amount obtained by subtracting the reactive current amount a from the current amount i and the previously stored proportional constant c (c · (i−
a)) is calculated as the pressure Fi at which the pad 12b is pressed against the disk 11.

Steps 224 to 232 are the respective pressures Fsmin, Fsmax, calculated in the above steps 218 to 222.
This is a process of setting, as the calculated pressure Fx, the most appropriate pressure that can be considered as the pressure actually pressing the pad 12b against the disk 11 in Fi. The pressure Fi calculated based on the current amount i in step 222 is the lower limit pressure F calculated based on the accumulated displacement amount S in step 218.
When it is less than smin, the microcomputer 30
Based on the determination of “YES” in step 224,
In step 226, the lower limit pressure Fsmin is calculated as the pressure Fx.
Set as. When the pressure Fi is equal to or higher than the upper limit pressure Fsmax calculated based on the accumulated displacement amount S in step 220, the determination in step 224 is “NO” and the determination in step 228 is “YES”. The upper limit pressure Fsmax is set as the calculated pressure Fx. When the pressure Fi is larger than the lower limit pressure Fsmin and smaller than the upper limit pressure Fsmax (in the state shown in FIG. 6), it is judged in Steps 224 and 226 that each is “NO”, and then Step 232 is performed. Then, the pressure Fi is set as the calculated pressure Fx.

Steps 234 to 244 are processes for determining the correction value k using the calculated pressure Fx set above under a predetermined condition. In this case, the microcomputer 30
First, at step 234, the timer count value TM
It is determined whether 1 is a predetermined time T1 (for example, 10 minutes) or more. The timer count value TM1 is for measuring the elapsed time from the previous determination of the correction value k,
The predetermined time T1 is initially set by an unillustrated initial setting. Therefore, first, the microcomputer 30 advances the program to step 238 based on the determination of “YES”.

In step 236, the detected pressure Fm input in step 106 of FIG. 3 is the predetermined pressure F0.
Determine if greater than. At this time, the detected pressure Fm
Is less than or equal to the predetermined pressure F0, the microcomputer 30 determines "NO" and temporarily ends the correction value updating process in step 246. On the other hand, when the detected pressure Fm is larger than the predetermined pressure F0, the microcomputer 30 determines “YES” and executes the program in step 23.
Proceed to 8.

In step 238, it is determined whether the timer count value TM2 is equal to or longer than the predetermined time T2 (for example, 200 milliseconds). Timer count value TM2
Is to measure the time during which the detected pressure Fm input in step 106 of FIG. 3 is kept constant by the processing described later. At this time, if the timer count value TM2 has reached the predetermined time T2, the microcomputer 3
0 advances the program to step 240 based on the judgment of “YES”.

In step 240, the quotient (Fx / Fm) of the calculated pressure Fx set in any of steps 226, 230 and 232 by the detected pressure Fm is
It is calculated as a correction value k. As a result, the correction value k is determined. At this time, the microcomputer 30 resets the timer count value TM1 to the value “0” in step 242, and temporarily ends the correction value updating process in step 246.

By resetting the timer count value TM1 in step 242, the microcomputer 30 thereafter determines "NO" when executing step 234 and advances the program to step 244. In step 244, step 1 in FIG.
It is determined whether the detected pressure Fm input at 06 is abnormal. Specifically, when the difference between the same pressure Fm and the detected pressures Fm of the other three wheels is equal to or more than a predetermined pressure, the pressure Fm is determined to be abnormal. At this time, if it is not determined that the pressure Fm is abnormal, the microcomputer 30 once ends the correction value updating process in step 246 based on the determination of “NO”.

Thereafter, the microcomputer 30 executes the correction value updating process of the step 122 during the circulation process of the steps 102 to 122 of FIG. 3, and the steps 200 to 204, 214, 216, 208, 210, Two
The processing consisting of 18 to 234, 244, and 246 is repeatedly executed, and the calculated pressure Fx is continuously updated and set in steps 226, 230, and 232. When the shaft 24 is separated from the pad 12b and the pad 12b is separated from the disk 11 during the same repeated execution, the stroke switch 28 is turned off, and the microcomputer 30 repeats the processing including the steps 200 to 212 and 246. Get to run.

On the other hand, the above steps 200 to 234, 24
3 is repeatedly executed, step 11 in FIG.
2, the detected pressure F input in step 106
m is corrected in each case by the correction value k determined in step 240, and the corrected pressure Fm ′ (= k · Fm)
Is set as. Then, the operation of the electric motor 20 is controlled in steps 116 to 120 based on the corrected pressure Fm ′.

By the way, the microcomputer 30
During the circulation processing of steps 102 to 122, the timer 30
Every time a measures a predetermined short time, the timer interrupt program of FIG. 5 is repeatedly executed by interruption. Every time the microcomputer 30 starts executing the timer interrupt program in step 300, the microcomputer 30 executes timer count value T in steps 304 and 308, respectively.
The value "1" is added to M1 and TM2. By this repeated execution, the timer count values TM1 and TM2 respectively measure time. The timer count value TM1,
Each time measured by TM2 is set to a predetermined time T1 or T2 by the processing of steps 302 and 306, respectively.

A predetermined time T1 has elapsed since the timer count value TM1 was reset to the value "0" in step 242 of FIG. 4, that is, the correction value k was determined in step 240, and the timer count value TM1 When the time count reaches the same time T1, the microcomputer 30
Based on the determination of “YES” in step 234,
The program proceeds again to step 236 and thereafter. As a result, the correction value k is again determined and updated in step 240 on condition that the detected pressure Fm is larger than the predetermined pressure F0 and the timer count value TM2 is the predetermined time T2 or more. Through this repeated execution, the correction value k is determined and updated every predetermined time T1. In addition, the previous correction value k
Even if the predetermined time T1 has not elapsed since then, if the detected pressure Fm becomes abnormal, the microcomputer 3 determines based on the determination of “YES” in step 244.
0 advances the program to step 236 and subsequent steps, and the correction value k
To update.

By the way, the microcomputer 30
Every time the detected pressure Fm is input in step 106 of FIG. 3, the input detected pressure Fm is input in step 108.
However, it is determined whether or not the detected pressure Fm input last time has changed by a predetermined minute pressure or more. If there is the same change at this time, the timer count value TM2 is reset to the value "0" in step 110 based on the determination of "YES". If there is no such change, based on the judgment of "NO", the program proceeds directly to step 112 and subsequent steps to avoid the reset process of step 110, and to continue the time count by the timer count value TM2. By this repeated execution, the timer count value TM2 measures the time during which the detected pressure Fm is kept constant. If the timer count value TM2 has not reached the predetermined time T2, the microcomputer 30 determines the correction value in step 240 based on the determination of "NO" when executing step 238 of FIG. To avoid.

Further, steps 102 to 122 in FIG.
If an abnormality occurs in the stroke switch 28 during the circulation process of, the microcomputer 30 avoids the determination process of step 204 based on the determination of "NO" in step 202. As a result, the setting process of the cumulative displacement amount S in the step 206 is prohibited, and the step 214 is performed regardless of the output signal of the stroke switch 28.
.. to 216, the differential displacement amount d due to the cumulative displacement amount S
The accumulation of S is continued.

As described above, in the above embodiment,
The detection signal from the rotary encoder 26 is converted into a converter 32.
By the displacement amount d of the pad 12b with respect to the disk 11
The cumulative displacement amount S is calculated by converting the signal into a signal representing S and accumulating the differential displacement amount dS ′ of the displacement amount dS in the state where the pad 12b is in contact with the disk 11. And
Based on this accumulated displacement amount S, steps 218 and 2 in FIG.
At 20, the lower limit pressure Fsmin and the upper limit pressure F, which are considered as the pressure at which the pad 12b is pressed against the disk 11, are considered.
Calculate smax. Further, the current flowing through the electric motor 20 is measured by the ammeter 33, and the pressure Fi at which the pad 12b is pressed against the disk 11 is calculated in step 222 based on the measured current amount i. Then, the correction value k is determined in step 240 based on the most appropriate pressure that is considered as the pressure at which the pad 12b is actually pressed against the disk 11 among the above-mentioned respective pressures Fsmin, Fsmax, Fi, and the pressure sensor k is determined. The pressure Fm detected by 27 is corrected using the same correction value k to obtain the corrected pressure Fm ′.
And the electric motor 2 based on the same corrected pressure Fm ′.
0 is controlled. Therefore, the pressure Fm detected by the pressure sensor 27 is used as the correction pressure Fm ′ and the pad 12 is corrected.
Since b accurately represents the actual pressure applied to the disk 11, the electric motor 20 is properly controlled,
The wheels are properly braked.

Further, the contact of the pad 12b with the disk 11 is detected by the stroke switch 28, and at the same time, the amount of current flowing in the electric motor 20 is the reactive current amount a.
Is stored as The pressure Fi is measured by the ammeter 3
It is calculated based on the current amount (ia) obtained by subtracting the reactive current amount a from the current amount i measured in 3. In this case, since the current amount (ia) accurately represents the current amount of the current flowing through the electric motor 20 that is converted into the pressure that actually pushes the pad 12b against the disk 11, the pressure F
i will more accurately represent the actual pressure with which the pad 12b is pressed against the disk 11. Therefore, since the detected pressure Fm is corrected by the correction value k determined based on the same pressure Fi, the actual pressure with which the pad 12b is pressed against the disk 11 is more accurately represented as the correction pressure Fm '. As a result, the electric motor 20 is controlled more appropriately, and the wheels are more appropriately braked.

Further, the determination of the correction value k is prohibited when the pressure Fm detected by the pressure sensor 27 is equal to or lower than the predetermined pressure F0 by the determination processing of step 236 of FIG. . As a result, the pad 12
b is pressed against the disk 11 with a small pressure,
That is, the detected pressure Fm, the accumulated displacement amount S, and the current amount i contained in the detected pressure F are large in the ratio of the error increases.
Since it is avoided that the correction value k is determined based on m, the accumulated displacement amount S, and the current amount i, the correction value k is always kept appropriate. Therefore, the detected pressure Fm is the same as the correction value k.
Since it is corrected by, the correction pressure Fm ′ always accurately represents the actual pressure at which the pad 12b is pressed against the disk 11. As a result, the electric motor 20 is always controlled appropriately and the wheels are always properly braked.

Further, the correction value k is determined by referring to FIG.
By the processing of steps 108, 110, and 238 in step 4,
The pressure Fm detected by the pressure sensor 27 is the predetermined time T
It is only allowed if it is held constant for two days. As a result, the correction value k is determined based on the respective detections in a state where the position of the pad 12b with respect to the disk 11 is not fixed, that is, in a state where the rotary encoder 26, the pressure sensor 27, and the ammeter 33 make the detections unstable. Since this is avoided, the correction value k is always kept appropriate. Therefore, the detected pressure Fm is corrected by the same correction value k, so that the corrected pressure Fm ′ always represents the actual pressure at which the pad 12b is pressed against the disk 11. As a result, the electric motor 20 is always controlled appropriately and the wheels are always properly braked.

In the above embodiment, the correction value k is determined by using both the cumulative displacement amount S and the current amount i, but for simplicity, of the cumulative displacement amount S and the current amount i. Even if only one of them is used to determine the correction value k, the effect of the present invention can be expected accordingly.

For example, when the correction value k is determined based only on the cumulative displacement amount S, the steps 208, 212, 222 to 230 are omitted in the correction value updating process of FIG. Instead of calculating the lower limit pressure Fsmin and the upper limit pressure Fsmax of 220, a process of uniquely calculating the pressure at which the pad 12b is pressed against the disk 11 with respect to the cumulative displacement amount S may be executed. Specifically, the above step 218,
An appropriate proportional constant b between the proportional constants b1 and b2 used in 220 is stored in advance in the microcomputer 30, and the product of the cumulative displacement amount S and the proportional constant b is calculated as the calculated displacement amount Fx. It is better to set it (see FIG. 8).

When the correction value k is determined based on only the current amount i, it is preferable to omit the processing of steps 218, 220, 224 to 230 in the correction value updating processing of FIG. In this case, for simplicity,
Even if consideration for the reactive current amount a is omitted,
The effects of the present invention can be expected accordingly. In this case, further steps 202 to 206, 210, 212
It is sufficient to omit the processes of to 216 and always set the value of the reactive current amount a used in step 222 to "0".

In the above embodiment, a disc type brake is used as the brake 10, but even if a drum type brake is used as the brake 10, the effect of the present invention can be expected sufficiently. It is possible.

[Brief description of drawings]

FIG. 1 is an overall block diagram of a vehicle brake device according to an embodiment of the present invention.

2 is a vertical cross-sectional view of the brake of FIG.

FIG. 3 is a flowchart showing a main program executed by the microcomputer of FIG.

FIG. 4 is a flowchart showing details of a correction value updating process in FIG.

5 is a flowchart showing a timer interrupt program executed by the microcomputer of FIG.

FIG. 6 is a graph showing the relationship between the cumulative displacement amount S and the lower limit pressure Fsmin and the upper limit pressure Fsmax.

FIG. 7 is a graph showing the relationship between the current amount i and the pressure Fi.

FIG. 8 is a graph showing the relationship between the cumulative displacement amount S and the pressure Fx in the modification of the embodiment.

[Explanation of symbols]

10 ... Brake, 11 ... Disc, 12a, 12b ... Pad, 20 ... Electric motor, 26 ... Rotary encoder, 27
... pressure sensor, 28 ... stroke switch, 30 ... microcomputer, 32 ... converter, 33 ... ammeter, BP
…break pedal.

Claims (8)

[Claims] 1. A rotating body that rotates integrally with a wheel; a friction member that is provided so as to face the rotating body and brakes the rotation of the wheel by being pressed against the rotating body; Is applied to a vehicle brake including an electric actuator that displaces the friction member and presses it against the rotating body, and a pressure sensor that detects the pressure at which the friction member is pressed against the rotating body, and is detected by the pressure sensor. In an electric control device for a vehicle brake, which includes an actuator control unit that controls the electric actuator based on the pressure, a displacement amount detection unit that detects a displacement amount of the friction member, and a displacement amount detection unit that detects the displacement amount. And a correction unit that determines a correction value based on the displacement amount and corrects the pressure detected by the pressure sensor using the correction value. Electric control apparatus for a vehicle brake, characterized in that provided. 2. A rotating body that rotates integrally with a wheel, and a rotating body that is provided so as to face the rotating body and is pressed against the rotating body to brake the rotation of the rotating body to brake the rotation of the wheel. A pressure applied to a vehicle brake including a friction member and an electric actuator that displaces the friction member according to the supply of an electric current and presses the friction member against the rotating body, and the friction member detects the pressure applied to the rotating body. An electric control device for a vehicle brake, comprising: a sensor; and an actuator control unit that controls a current supplied to the electric actuator based on a pressure detected by the pressure sensor, and measures a current flowing through the electric actuator. A correction value is determined based on the current measuring means and the amount of current measured by the current measuring means, and the correction value is determined using the correction value. Electric control apparatus for a vehicle brake, characterized in that a correction means for correcting the pressure detected by the sensor. 3. A rotating body that rotates integrally with a wheel, a friction member that is provided so as to face the rotating body and brakes the rotation of the wheel by being pressed against the rotating body, and a friction member that responds to supply of an electric current. Is applied to a vehicle brake including an electric actuator that displaces the friction member and presses it against the rotating body, and a pressure sensor that detects the pressure at which the friction member is pressed against the rotating body, and is detected by the pressure sensor. In an electric control device for a vehicle brake, which includes an actuator control unit that controls a current supplied to the electric actuator based on a pressure, a displacement amount detection unit that detects a displacement amount of the friction member, and the displacement amount. A lower limit pressure considered as the pressure at which the friction member is pressed against the rotating body based on the displacement amount detected by the detection means, and A first pressure calculating means for calculating a limiting pressure; a current measuring means for measuring a current flowing through the electric actuator; and a pressure at which the friction member is pressed against the rotating body based on the amount of current measured by the current measuring means. And a correction value for the pressure detected by the pressure sensor, wherein the pressure calculated by the second pressure calculation means is less than or equal to the lower limit pressure calculated by the first pressure calculation means. If the pressure is lower than the lower limit pressure calculated by the first pressure calculating unit and smaller than the upper limit pressure, the lower limit pressure is determined using the lower limit pressure. 2 The pressure calculated by the pressure calculation means is used for determination, and the pressure calculated by the second pressure calculation means is calculated by the first pressure calculation means. When the pressure is equal to or higher than the pressure, the upper limit pressure is used for the determination, and the correction value is used to correct the pressure detected by the pressure sensor. Electric control device. 4. An electric control device for a vehicle brake according to claim 2 or 3, wherein contact detecting means detects contact of the friction member with the rotating body, and the contact detecting means. And a current storage means for storing the amount of current flowing through the electric actuator based on the measurement by the current measuring means when the means detects the contact of the friction member with the rotating body, and is detected by the pressure sensor. A correction value for the pressure to be determined based on a current amount obtained by subtracting the current amount stored in the current storage unit from the current amount measured by the current measuring unit. Control device for the vehicle brake. 5. The electric control device for a vehicle brake according to any one of claims 1 to 4, wherein the correction means determines the correction value at predetermined time intervals. An electrical control device for a featured vehicle brake. 6. An electric control device for a vehicle brake according to any one of claims 1 to 4, wherein an abnormality detecting means for detecting an abnormality in pressure detected by the pressure sensor. And an electric control device for a vehicle brake, wherein the correction means determines the correction value when an abnormality is detected by the abnormality detection means. 7. An electric control device for a vehicle brake according to any one of claims 1 to 6, wherein the correction means detects the determination of the correction value by the pressure sensor. An electric control device for a vehicle brake, wherein the applied pressure is prohibited when the applied pressure is below a predetermined pressure. 8. An electric control device for a vehicle brake according to any one of claims 1 to 7, wherein the correction means detects the determination of a correction value by the pressure sensor. An electric control device for a vehicle brake, wherein the pressure is allowed only when the pressure is kept constant for a predetermined time.