JP4233980B2 - Brake control device - Google Patents

Description

  The present invention relates to a brake control device that recirculates brake fluid stored in a reservoir to a master cylinder side by a motor-driven pump, and more particularly to a technique for checking the motor lock of the motor.

Conventionally, as this type of brake control device, a technique is known in which a motor is determined and driven at an appropriate timing to determine whether or not a motor lock has occurred based on the terminal voltage due to inertial rotation of the motor. (See Patent Document 1).
JP-A-3-96469

  However, in the invention of the above-mentioned Patent Document 1, since it is necessary to increase the rotational speed of the motor to the steady rotational speed in order to reliably obtain the inertial rotation of the motor, the driving time of the motor becomes long. There was a problem that the operation sound continued to be generated and the check took time.

  The present invention has been made paying attention to the above-mentioned problems, and an object of the present invention is to provide a brake control device capable of checking the motor lock in a shorter time than the conventional invention.

In the invention of claim 1 of the present invention, in the brake control device for returning the brake fluid stored in the reservoir to the master cylinder side by the pump driven by the motor, the terminal voltage detecting means for detecting the terminal voltage of the motor; Terminal voltage storage means for storing a terminal voltage immediately after the motor is driven and before the motor reaches the steady rotational speed, and voltage threshold value calculation means for calculating a voltage threshold value based on the terminal voltage stored by the terminal voltage storage means An abnormality determination drive command is output to the motor, and the detected threshold voltage is set lower than the terminal voltage generated during the steady rotation of the motor within the time until the motor reaches the steady rotation speed. Motor abnormality determining means for determining that there is no abnormality in the motor and stopping the abnormality determination drive command of the motor when exceeded.

  Therefore, the motor lock can be checked in a shorter time, and the driving time of the motor can be shortened to shorten its operating sound.

In addition , since the voltage threshold is determined based on the terminal voltage at the time of starting the motor, the height of the voltage threshold can correspond to the battery voltage at that time, and motor lock occurs compared to the case where the voltage threshold is determined in advance on a map. Detection accuracy can be improved.

Hereinafter, embodiments of the brake control device of the present invention will be described.
FIG. 1 is an overall view of a brake control device according to an embodiment of the present invention, FIG. 2 is a hydraulic circuit diagram of a main part of the brake control device according to the present embodiment, and FIG. 3 is an IGN power supply voltage in a control unit of the brake control device according to the present embodiment. FIG. 3 is a circuit diagram showing a circuit configuration of a portion that detects a terminal voltage.
FIG. 4 is a flowchart showing the flow of a motor abnormality determination process executed by the control unit of the brake control apparatus of this embodiment, FIG. 5 is a time chart of terminal voltages in the motor lock check process of this embodiment, and FIG. It is a time chart of the terminal voltage in the motor lock check processing when the voltage does not exceed the voltage threshold value.

  First, an overall view of a brake control device according to an embodiment of the present invention and a main part hydraulic circuit diagram of the brake control device will be described.

As shown in FIGS. 1 and 2, the brake control device of this embodiment includes a brake unit 1, a control unit 2, a master cylinder 3, G switches 4 a and 4 b, wheel speed sensors 5 a to 5 d, and a wheel cylinder 6. It is said.
As shown in FIG. 2, the brake unit 1 mainly includes switching valves 1 a and 1 b, a reservoir 1 c, a pump 1 d, and a motor M that drives the pump P.
The switching valve 1a switches between a state in which the brake hydraulic pressure from the master cylinder 3 communicates with the wheel cylinder 6 and a state in which the hydraulic pressure in the wheel cylinder 6 communicates with the reservoir 1c.
The switching valve 1b switches the state in which the brake fluid pressure from the master cylinder 3 is communicated with the wheel cylinder 6 and the oil path between the master cylinder 3 and the wheel cylinder 6 to a non-communication state.

The reservoir 1c temporarily stores brake fluid in order to reduce the brake fluid pressure increased to the wheel cylinder 6.
The pump P is driven by the motor M, and returns the brake fluid stored in the reservoir 1c to the master cylinder 3 side at the time of decompression.
The G switches 4a and 4b detect vehicle body acceleration in the traveling direction of the wheel and in the yaw direction.
The control unit 2 calculates the road surface friction coefficient and the vehicle body deceleration by the wheel speed from the wheel speed sensors 5a to 5d and the vehicle body acceleration from the G switches 4a and 4b, and increases the brake fluid pressure of the wheel cylinder 6 Execute ABS control to hold and decompress. Here, the operation in each brake state will be described.

<During normal braking / increasing pressure>
When a brake operation is performed by the driver, the brake fluid pressure of the wheel cylinder 6 is increased by the master cylinder 3, and the brakes of the wheels 7a to 7d are braked.
Further, after reducing the brake fluid pressure on the wheel cylinder 6 side, when increasing the brake fluid pressure, the brake fluid pressure is supplied from the master cylinder 3 to the wheel cylinder 6 by switching the switching valves 1a and 1b. Increase the pressure.

<At decompression>
When the vehicle deceleration (or slip ratio, etc.) approaches the slip limit during braking, the switching valve 1a is driven, the brake hydraulic pressure on the wheel cylinder 6 side is released to the reservoir 1c side, and the wheel cylinder pressure is reduced. Decrease deceleration (or slip rate, etc.).

<When holding>
During braking, when the vehicle deceleration (or slip ratio, etc.) is in a good state close to the slip limit, the switching valves 1a and 1b are driven to maintain the brake fluid pressure on the wheel cylinder side.
As described above, the wheel is prevented from being locked by switching the pressure increasing / depressurizing / holding control according to the braking state and the road surface condition, and the braking performance close to the limit is obtained in a stable region.

Next, a circuit diagram showing a circuit configuration of a portion for detecting the IGN power supply voltage and the terminal voltage in the control unit will be described with reference to FIG.
As shown in the figure, a CPU 10 is provided in the control unit 2, and the CPU 10 includes a terminal voltage detection means 11, a terminal voltage storage means 12, a voltage threshold value calculation means 13, a motor abnormality determination means 14, and an IGN power source. The voltage detection means 15 is connected.
The terminal voltage detection means 11 receives the terminal voltage on the battery 16 side (upstream) of the motor M from the CPU 10 via the interface 17a, or receives the terminal voltage on the GND side (downstream) of the motor M via the interface 17b. Receive from.
The terminal voltage storage means 12 individually stores the terminal voltages detected by the terminal voltage detection means 11.

The voltage threshold value calculation means 13 is for calculating a voltage threshold value based on the terminal voltage stored in the terminal voltage storage means 12, and the voltage threshold value is, for example, from immediately after the IGN power is turned on to a predetermined time. Is set based on the decrease in the differential value calculated from the terminal voltage stored in the terminal voltage storage means 11 (corresponding to (C) described later).
Alternatively, the voltage threshold is set to a value obtained by multiplying the terminal voltage detected first by a predetermined coefficient, or a value obtained by multiplying the average value of a plurality of terminal voltages stored in the memory by a predetermined coefficient, etc. Can be set as appropriate.
The motor abnormality determination means 14 includes a first abnormality determination unit 14a and a second abnormality determination unit 14b, and an abnormality of the motor M is detected by the relay 18 and the transistor 19 by switching the motor drive signal ON / OFF via the CPU 10. Judgment drive control is performed.
The IGN power supply voltage detection means 15 receives the terminal voltage on the battery 16 side from the CPU 10 via the interface 20 by the relay 18.
Further, the control unit 2 includes a plurality of memories such as a counter A and a counter B.

Next, the failure determination of the motor M of the brake control device of this embodiment will be described.
The motor M is used when the brake fluid stored in the reservoir 1c is returned to the master cylinder 3 side at the time of decompression in order to adjust the oil amount balance in the entire brake system.
At this time, when an abnormality occurs in the motor M and the recirculation cannot be sufficiently performed, the reservoir 1c becomes full, and the pressure reduction control cannot be performed sufficiently, so that proper brake control cannot be achieved.
Therefore, in order to achieve good brake control, it is desirable to determine the failure of the motor M every time the vehicle travels, and to promptly respond to the driver immediately if there is an abnormality so as to notify the driver. However, when the failure determination drive of the motor M is performed for this failure determination for a long time, the driver notices the drive sound and the vibration caused by the drive, and the feeling is deteriorated.

  On the other hand, the brake control apparatus of the present embodiment makes a failure determination by causing the motor M to perform a failure determination drive when the engine is started (immediately after the IGN power is turned on).

Hereinafter, the flow of the failure determination process executed by the control unit 2 of this embodiment will be described with reference to the flowchart of FIG.
In step S100, the terminal voltage of the memory in the control unit 2 is reset and the process proceeds to S101. At this time, the counter A starts counting elapsed time.
In step S101, when the IGN power supply is turned on, the motor abnormality determination means 14 turns on the motor drive signal to drive the motor M for failure determination, and the process proceeds to S102.
In step S102, it is determined whether or not the elapsed time stored in the counter A has exceeded a predetermined time t1 set in advance. If not, the process proceeds to S103, and if it has exceeded, the process proceeds to step S105.
In S103, the terminal voltage detection means 11 detects the terminal voltage of the motor M, the terminal voltage storage means 12 individually stores the terminal voltage in the memory in the control unit 2, and the process proceeds to step 104.
In S104, the counter A is incremented and the process returns to S102.
Here, S102 to S104 are repeated until the counter A exceeds the predetermined time t1, and the terminal voltage storage means 12 stores a plurality of terminal voltages individually.

In S105, the voltage threshold calculation means 13 calculates a voltage threshold based on the terminal voltage stored in the terminal voltage storage means 12, and the process proceeds to S106.
The voltage threshold is set lower than the terminal voltage generated at the steady rotation speed of the motor M.
In S106, the first abnormality determination unit 14a of the motor abnormality determination unit 14 determines whether or not the terminal voltage exceeds the voltage threshold value. If not, the process proceeds to S107 and the counter B indicates the elapsed time. Start counting.
On the other hand, when it exceeds, it shifts to S111, determines that there is no abnormality in the motor M, stops the abnormality determination driving of the motor M, and ends the failure determination.
In S107, it is determined whether or not the counter B has exceeded the predetermined time t2. If not, the process proceeds to S108, and if it has exceeded, the process proceeds to Step S109.
In S108, the counter B is incremented and the process returns to S106.
Here, S106 to S108 are repeated until the terminal voltage does not exceed the voltage threshold and the counter B exceeds the predetermined time t2.

In S109, after the motor M is driven for a predetermined time t3 (time when the motor reaches the normal rotation speed at normal time), the second abnormality determination unit 14b generates a motor lock due to the terminal voltage immediately after the motor drive signal is turned OFF. If it is determined that there is an abnormality, the process proceeds to S110. If it is determined to be normal, the process proceeds to S111.
In S110, it is determined that the motor lock has occurred and the failure determination is terminated, and the driver is informed by a warning sound or a warning light.

FIG. 5 shows a time chart of terminal voltages in the motor lock check process of this embodiment.
At time t11, since a predetermined time t1 has elapsed since the motor drive signal ON, a voltage threshold is set from a plurality of terminal voltages (three points in the figure) stored in the memory in order for each increment of the counter A. Further, the counter B starts to count up. In the flowchart of FIG. 4, the process proceeds from S102 → S105 → S106 → S107.

At time t12, since the value of the counter B counted from time t11 has passed the predetermined time t2, the first abnormality determination unit 14a determines whether or not the terminal voltage has exceeded the voltage threshold value. Since the terminal voltage exceeds the voltage threshold, the motor M is determined to be normal and the abnormality determination drive of the motor M is stopped. In the flowchart of FIG. 4, the process proceeds from S106 to S111.
In addition, the case where the terminal voltage of the motor M at the time of abnormality does not exceed a voltage threshold value with a dashed-dotted line is shown.

FIG. 6 shows a time chart of the terminal voltage in the motor lock check process in the case where the terminal voltage does not exceed the voltage threshold due to a sudden drop in the battery voltage.
At time t21, since a predetermined time t1 has elapsed since the motor drive signal ON, a voltage threshold is set from a plurality of terminal voltages (three points in the figure) stored in the memory in order for each increment of the counter A. Further, the counter B starts to count up. In the flowchart of FIG. 4, the process proceeds from S102 → S105 → S106 → S107.

  At time t22, since the value of the counter B counted from time t21 has passed the predetermined time t2, the first abnormality determination unit 14a determines whether or not the terminal voltage has exceeded the voltage threshold value. Since the terminal voltage does not exceed the voltage threshold value, the abnormality determination drive is performed until the motor M reaches the steady rotation speed (predetermined time t3). In the flowchart of FIG. 4, the process proceeds from S107 to S109.

At time t23, since the predetermined time t3 has elapsed from time t22, the motor drive signal is turned off, and whether or not the motor lock has occurred due to the terminal voltage immediately after the motor drive signal is turned off by the second abnormality determination unit 14b. To be judged. Since the terminal voltage of a normal motor is gently lowered, it is determined that there is no abnormality in the motor M. In the flowchart of FIG. 4, the process proceeds from S109 to S111.
The case where the terminal voltage of the motor M at the time of abnormality does not exceed the voltage threshold at time t22 is shown by a one-dot chain line in the figure.

  As shown by an arrow A in FIG. 6, the terminal voltage of a normal motor gradually decreases, whereas as shown by an arrow B in FIG. 6, the terminal voltage of the motor at the time of abnormality decreases rapidly.

  As described above, in the brake control device of this embodiment, the terminal voltage of the motor M has exceeded the voltage threshold when the predetermined time t2 has elapsed (within the time until the motor reaches the steady rotational speed). In this case, the first abnormality determination unit 4a determines that there is no abnormality in the motor and stops the failure determination drive of the motor M, so that the motor lock can be checked in a shorter time than the conventional invention. Corresponding).

Further, when the terminal voltage of the motor M does not exceed the voltage threshold after a predetermined time t 2 as suspected motor lock occurs, the motor M predetermined time t3 (the motor constant speed during normal Until the terminal voltage exceeds the voltage threshold. If not, the second abnormality determination unit 4b locks the motor due to the terminal voltage immediately after the motor drive signal is turned OFF. For example, when the terminal voltage does not exceed the voltage threshold due to a sudden drop in the battery voltage, it can be prevented that the motor is erroneously determined to be abnormal, and detection of the occurrence of motor lock. Accuracy can be improved (corresponding to (I) described later).
On the other hand, if there is a suspicion of the occurrence of motor lock, if the terminal voltage exceeds the voltage threshold while driving the motor M until the predetermined time t3, the failure determination drive of the motor M is stopped. If there is, the motor M does not necessarily continue to be driven until the predetermined time t3, and the driving time of the motor M can be minimized (corresponding to (B) described later).

  Furthermore, since the voltage threshold is determined based on the terminal voltage at the time of starting the motor, the height of the voltage threshold can correspond to the battery voltage at that time, and motor lock occurs compared to the case where the voltage threshold is determined in advance on a map Detection accuracy can be improved.

Although the embodiments of the present invention have been described above, the specific configuration of the present invention is not limited to the embodiments, and the present invention includes any design changes that do not depart from the gist of the invention. It is.
For example, the predetermined times t1 and t2 can be arbitrarily set as long as they are within the time until the normal motor reaches steady rotation.

  Furthermore, technical ideas other than the claims that can be understood from the above-described embodiments and examples will be described together with the effects thereof.

(A) In the brake control device according to claim 1,
When the terminal voltage of the motor does not exceed the voltage threshold, the abnormality determination means drives the motor until the time when the motor at normal time reaches the steady rotation speed, and then locks the motor by detecting the terminal voltage detected A brake control device that determines whether or not the occurrence of a brake is occurring.

  That is, it is possible to prevent erroneous determination that the motor lock has occurred when the terminal voltage does not exceed the voltage threshold due to a sudden drop in the battery voltage or the like, and improve the detection accuracy of the motor lock occurrence. be able to.

(B) In the brake control device according to claim 1 or (a) above,
When the terminal voltage of the motor does not exceed the voltage threshold, the motor is driven for a predetermined time until the normal motor reaches the steady rotation speed,
When the motor terminal voltage exceeds a voltage threshold during the predetermined time, it is determined that motor lock has not occurred, and the motor abnormality determination drive is stopped.

  That is, if there is a suspicion of the occurrence of motor lock, if the terminal voltage exceeds the voltage threshold while the motor is driven for a predetermined time, it is determined that no motor lock has occurred and the motor failure determination drive is stopped. Therefore, when there is a suspicion of the occurrence of motor lock, the motor does not always continue to be driven until a predetermined time, and the drive time of the motor can be minimized.

(C) In the brake control device according to claim 1 or (a) above,
The voltage threshold calculation means sets the voltage threshold based on a decrease in the differential value calculated from the terminal voltage stored by the terminal voltage storage means from immediately after the IGN power is turned on to a predetermined time. apparatus.

  That is, the increase of the terminal voltage immediately after driving the motor can be accurately predicted, and the voltage threshold can be set appropriately.

1 is an overall view of a brake control device according to an embodiment of the present invention. It is a principal part hydraulic circuit diagram of the brake control apparatus of a present Example. It is a circuit diagram which shows the circuit structure of the part which detects the IGN power supply voltage and terminal voltage in the control unit of the brake control apparatus of a present Example. It is a flowchart which shows the flow of the abnormality determination process of the motor performed with the control unit of the brake control apparatus of a present Example. It is a time chart of the terminal voltage in the motor lock check process of a present Example. It is a time chart of the terminal voltage in the motor lock check process when the terminal voltage does not exceed the voltage threshold value.

Explanation of symbols

M Motor P Pump 1 Brake unit 1a, 1b Switching valve 1c Reservoir 2 Control unit 3 Master cylinder 4a, 4b G switch 5a, 5b, 5c, 5d Wheel speed sensor 6 Wheel cylinder 7a, 7b, 7c, 7d Wheel 10 CPU
DESCRIPTION OF SYMBOLS 11 Terminal voltage detection means 12 Terminal voltage memory | storage means 13 Voltage threshold value calculation means 14 Motor abnormality determination means 14a 1st abnormality determination part 14b 2nd abnormality determination part 15 IGN power supply voltage detection means 16 Battery 17a, 17b, 20 Interface 18 Relay 19 Transistor 19

Claims (4)

In the brake control device for returning the brake fluid stored in the reservoir to the master cylinder side by a pump driven by a motor,
Terminal voltage detecting means for detecting a terminal voltage of the motor;
Terminal voltage storage means for storing the terminal voltage immediately after the motor is driven and before the motor reaches the steady rotational speed ;
Voltage threshold value calculation means for calculating a voltage threshold value based on the terminal voltage stored by the terminal voltage storage means;
An abnormality determination drive command is output to the motor, and the detected terminal voltage exceeds a voltage threshold set lower than the terminal voltage generated during steady rotation of the motor within the time until the motor reaches the steady rotation speed. A motor abnormality determination means for determining that the motor has no abnormality and stopping the motor abnormality determination drive command;
A brake control device comprising: The brake control device according to claim 1, wherein
When the terminal voltage of the motor does not exceed the voltage threshold, the abnormality determination means drives the motor until the time when the motor at the normal time reaches the steady rotation speed, and then the motor is detected by the detected terminal voltage. A brake control device that determines whether or not a lock has occurred. The brake control device according to claim 1 or 2,
If the terminal voltage of the motor does not exceed the voltage threshold, the abnormality determination means drives the motor for a predetermined time until the normal motor reaches the steady rotation speed,
When the motor terminal voltage exceeds a voltage threshold during the predetermined time, it is determined that motor lock has not occurred, and the motor abnormality determination drive is stopped. In the brake control device according to any one of claims 1 to 3,
The voltage threshold calculation means sets the voltage threshold based on a decrease in the differential value calculated from the terminal voltage stored by the terminal voltage storage means from immediately after the IGN power is turned on to a predetermined time. apparatus.

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