JP3266979B2 - Anti-skid control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid control device for controlling a brake fluid pressure so as to prevent a wheel lock at the time of sudden braking and to obtain a high braking stability and a short braking stop distance.

[0002]

2. Description of the Related Art In this type of control system, a battery voltage is supplied through a stabilizing circuit in order to stabilize the operation of the control circuit. However, when the battery voltage becomes abnormally high or becomes low. In this case, the output voltage of the stabilization circuit will not be constant, especially if the control voltage falls below the specified value, the oil supply capacity of the electromagnetic solenoid or pump that drives the brake control valve will decrease, and the anti-skid control will malfunction. May occur.

[0003] Therefore, such a control device is provided with a circuit for monitoring the battery voltage, and when the battery voltage is out of a specified range, an alarm is issued for a power supply abnormality, or anti-skid control is performed in consideration of safety. It is desirable to perform a so-called fail-safe operation of releasing and returning to normal brake control.

[0004]

However, during the anti-skid control, the motor for driving the pump for recovering the hydraulic pressure by increasing and decreasing the brake hydraulic pressure by turning on and off the solenoid is also required. Is turned on, a relatively large current is flowing from the battery,
In particular, a power supply abnormality due to a low battery voltage is likely to occur, in which case the anti-skid control is suddenly released, resulting in a sudden switch to normal brake control or an alarm output being issued, which is unnecessary. It can be confusing.

[0005]

SUMMARY OF THE INVENTION
No. 1740, "A power supply voltage monitoring circuit of an anti-skid control system" discloses that during anti-skid control and braking, fail-safe operation is not started even if an abnormality is detected in the power supply voltage. .

However, in this control, even if the anti-skid control is continued to ignore the abnormal decrease in the power supply voltage, if the power supply voltage is extremely reduced, the stable anti-skid control is performed as described above. He raised the issue that control could not be performed and control became unstable. The present invention has been made to solve the above-described problem, and an anti-skid that can achieve more stable anti-skid control by appropriately performing transition from anti-skid control or braking to fail-safe control. It is an object to provide a control device.

[0007]

According to a first aspect of the present invention, a threshold value for monitoring a power supply voltage abnormality is set, and when a power supply voltage abnormality is detected by comparison with the threshold value. In an anti-skid control device that performs a fail-safe process such as returning to a normal braking state, a braking detection unit that detects that braking is being performed, and a detection output of the braking detection unit is obtained. Threshold value changing means for changing a threshold value when the power supply voltage is abnormally detected.

According to the second aspect of the present invention, a threshold value for monitoring a power supply voltage abnormality is set, and when a power supply voltage abnormality is detected by comparison with the threshold value, a normal brake state is set. In an anti-skid control device that performs fail-safe processing such as returning, an anti-skid detection unit that detects that anti-skid control is being performed, and when a detection output of the anti-skid detection unit is obtained, Threshold value changing means for changing a threshold value when the power supply voltage is abnormally detected.

According to the third aspect of the present invention, a threshold value for monitoring an abnormality of the power supply voltage is set, and when the abnormality of the power supply voltage is detected by comparing with the threshold value, a normal brake state is set. In the anti-skid control device that performs fail-safe processing such as returning, the motor drive detecting means for detecting that the anti-skid control motor is being driven and the solenoid for controlling the brake fluid pressure are being energized. A solenoid energization detecting means for detecting, and a threshold changing means for changing a threshold value when the power supply voltage is abnormally detected when a detection output of the motor drive detecting means or the solenoid energization detecting means is obtained. , Is provided.

According to a fourth aspect of the present invention, a threshold value for monitoring a power supply voltage abnormality is set, and when a power supply voltage abnormality is detected by comparison with the threshold value, a normal brake state is set. In an anti-skid control device that performs fail-safe processing such as returning, an outflow current detection means for detecting an amount of current flowing from a power supply, an inflow current detection means for detecting an amount of current flowing into a power supply, and the current detection means. Threshold value changing means for changing a threshold value in the abnormality detection of the power supply voltage according to the amount of current supplied.

[0011]

In the first invention, while the braking detecting means detects that braking is being performed, the threshold changing means detects the lower limit V of the threshold value when the power supply voltage is abnormally detected.
Since a is changed to the lower value Vb, the abnormality determination criterion of the power supply voltage is relaxed, and the abnormality is not determined with a certain voltage drop, so that the process does not easily shift to the fail-safe processing.

In the first invention, the threshold value is changed during braking. However, in the second invention, the threshold value is similarly changed during the period when the anti-skid control is being performed.
The third invention is that the threshold value is changed while the anti-skid control motor is being driven or the electromagnetic solenoid is energized. The fourth invention is to change the threshold value by comparing the amount of current flowing out of the power supply with the amount of current flowing into the power supply.

[0013]

FIG. 1 is a control block diagram showing an embodiment of the apparatus of the first invention. 1 is a wheel speed sensor that detects an AC signal having a frequency proportional to the rotation of the wheel, and 2 calculates the acceleration / deceleration of the wheel based on the wheel speed detected by the wheel speed detection sensor 1, and the deceleration is An anti-skid control circuit that outputs a solenoid control signal for repeatedly increasing, decreasing, and maintaining the brake fluid pressure in a short cycle so that wheel lock does not occur when a predetermined value is exceeded due to sudden braking. As the anti-skid control circuit 2, for example, the one described in JP-B-55-28900 can be used.

The control signal output from the anti-skid control circuit 2 is input to the base of the power transistor 3 via the resistor R1. As a collector load of the power transistor 3, a valve (not shown) for controlling the brake fluid pressure is driven between the power supply line L from the battery 6 via the ignition switch 5 and the collector as described above. An electromagnetic solenoid 4 is connected to the electromagnetic solenoid 4, and the amount of electricity supplied to the electromagnetic solenoid 4 is changed to increase, decrease, and hold the brake fluid, thereby performing anti-skid control. On the other hand, the electromagnetic solenoid 4 is turned off. When the valve is closed, the anti-skid control is released, and the routine shifts to the normal brake control. 7 is the power line L 1
This is a stabilizing circuit that stabilizes 2V and outputs a stabilized voltage Vc of, for example, 8V. Anti-skid control circuit 2
Are supplied with the stabilized voltage Vc.

Reference numeral 9 denotes a comparator, to which a voltage of, for example, 5 V obtained by dividing 12 V of the power supply line L by the resistors R2 and R3 is input to a "-" input portion. This voltage is
Changes in response to a change in the terminal voltage of The 8V stabilized voltage Vc of the stabilizing circuit 7 is, for example, 4 V obtained by the voltage dividing circuit of the resistors R5 and R6.
For example, 3V is obtained by the voltage dividing circuit. These divided voltages are always kept constant even when the battery voltage changes.

The above-mentioned divided voltage 4 V or 3 V is selectively inputted to the "+" input portion of the comparator 9 through the switching contact 10Y of the relay 10. 11 is a brake switch which is turned on when the brake is depressed,
When the brake switch 11 is turned on, the battery voltage is applied to the base of the power transistor 12 via the resistor R10, so that the relay 10 connected as a collector load of the power transistor 12 is excited.

The output of the comparator 9 is a diode D2
, And the output thereof is connected to a resistor R
11 is applied to the base of the power transistor 14. An alarm lamp 15 is connected as a collector load of the power transistor 14. Buffer 13
Is applied also to the base of the power transistor 16, a relay 17 is connected as a collector load of the power transistor 16, and the back contact 17A of the relay 17 is inserted into the collector circuit of the power transistor 3. .

The control operation of the above circuit will be described below. When the brake is not applied, the brake switch 11 is off, and the power transistor 12 is in the switch-off state. Therefore, the relay 10 is off, and the switching contact 10Y is switched to the illustrated side.
Further, since a predetermined deceleration is not detected by the wheel speed sensor 1, no solenoid control signal for anti-skid control is output from the anti-skid control circuit 2, so that the output becomes low level. Therefore, the power transistor 3 is switched off.

A voltage of 4 V divided by resistors R5 and R6 is applied to a "+" input of the comparator 9 at the switching contact 10
Applied through Y. "-" of the comparator 9 to the input unit, the voltage V ₂₃ obtained by dividing by the resistors R2 and R3 is applied to drain current is small than the battery 6 In the time of such a non-braking, the power source line L is kept substantially 12V, thus substantially 5V is applied as the voltage V _23. In this case, the comparator 9 outputs a low level, and the low level is output from the buffer 13 via the diode D2. Therefore, the power transistors 14 and 16 are both switched off. Therefore, the alarm lamp 15 does not light up, and the contact 17A is in a conductive state due to the turning off of the relay 17, but since the power transistor 3 is turned off, the electromagnetic solenoid 4 is also turned off. Not done.

Meanwhile, the cause of or anything like In the time of such non-braking, if the voltage V ₂₃ is for example 3.5 V, since the comparator 9 outputs a high level, the buffer 13 is a high level As a result, the power transistors 14 and 16 are turned on, and the alarm lamp 15 is turned on to notify the abnormality of the power supply voltage. Further, the relay 17 is excited and the contact 17A is turned off. However, since the power transistor 3 is turned off, the electromagnetic solenoid 4 is turned off.
Is off, and no anti-skid control is performed.

Next, the case where the brake is applied will be described. At this time, the brake switch 11 is turned on, and when the power transistor 12 is turned on, the relay 10 is turned on.
Turns on, the switching contact 10Y switches,
3V divided by the resistors R8 and R9 is applied to the "+" input of the comparator 9. When the deceleration by the brake at this time is small and the predetermined deceleration signal is not output from the wheel speed sensor 1, only the low level signal is continuously output from the anti-skid control circuit 2, and at this time, as described above, When the power transistor 3 is turned off, the electromagnetic solenoid 4 is also turned off, so that anti-skid control is not performed.

Even when the divided voltage V23 at this time becomes 3.5V, which is lower than the original threshold value 4V, as in the case of the paragraph number [0020], both comparators 8, ₂₃
9 both output a low level, and thus, as described above,
The lighting lamp 15 is not lit, and the power supply voltage is determined to be normal.

On the other hand, if the voltage V ₂₃ is below 3V is now for the first time comparator 9 outputs a high level, thereby the buffer 13 also outputs a high level, as a result, the warning lamp 15 is lit The anti-skid control is not performed.

In this case, a sudden brake is applied. In this case, when the brake switch 11 is turned on, the relay 10 is turned on, and a signal of a predetermined deceleration is transmitted from the wheel speed sensor 1 to the anti-skid. When supplied to the control circuit 2, a high-level signal is output from the anti-skid control circuit 2, and as a result, the power transistor 3 is switched on. At this time, the divided voltage V ₂₃
Is 3 V or more, as described above, the power transistors 14 and 16 are switched off, so that the alarm lamp 15 is not turned on. Also, since the contact 17A of the relay 17 is conductive, the electromagnetic solenoid 4 is turned on. , Anti-skid control is performed.

[0025] when the voltage V ₂₃ the voltage of the power supply line L in this state is changed is below 3V, as described above, the power transistors 14 and 16 is switched on, the alarm lamp 15 is lit Then, the abnormality of the power supply voltage is notified, and the relay 17 is turned on and the contact 17A is turned off, so that the electromagnetic solenoid 4 is turned off, the anti-skid control is released, and the normal brake control is started. As can be seen in this, when braked, as above voltage V ₂₃ is immediately antiskid control even below 4V is not released, the first anti-skid control at the time below the 3V is released Has become.

FIG. 2 is a control block diagram showing one embodiment of the second invention, in which parts having the same functions as those in FIG. 1 are denoted by the same reference numerals. A solenoid control signal output from the anti-skid control circuit 2 during anti-skid control is provided with a new latch circuit 21 for latching. While the anti-skid control signal is being output by the latch circuit 21, a high-level signal is output from the latch circuit 21, and this signal is applied to the base of the driving power transistor 12 of the relay 10.

In the circuit configuration of FIG. 1 described above, the threshold value, which is the criterion for canceling the anti-skid control, is changed downward when the brake is applied, but in the circuit configuration of FIG. It will be appreciated that when anti-skid control is being performed, the threshold will shift downward.

FIG. 3 shows an embodiment of the third invention. Here, only the drive circuit of the relay 10 is shown due to space limitations, and the same parts as those in FIGS. The other circuit configurations are the same as those in FIGS. 1 and 2. A relay 31 is connected in parallel with the electromagnetic solenoid 4, a contact 31A of the relay 31 and resistors R11 and R12 are connected in series between the stabilized voltage Vc and the ground, and a connection point between the resistors R11 and R12. Is or gate 3
2 is connected to one input unit. The control signal of the anti-skid control motor output from the anti-skid control circuit 2 is supplied to the power transistor 3 via the resistor R13.
3 is connected to a relay 34 for controlling the anti-skid control motor as a collector load of the power transistor 33. The drive circuit for the anti-skid control motor is omitted in FIGS. 1 and 2 because it is not directly related. The motor control signal is
It is also applied to the other input of the OR gate 32. The output of the OR gate 32 is connected to a power transistor 10 for controlling a threshold value changing relay 10 via a resistor R14.
Applied to the base.

In this circuit configuration, when the electromagnetic solenoid 4 is turned on, the relay 31 is also turned on and its contact 3
When 1A is turned on, a high level divided by the resistors R11 and R12 is applied to one input portion of the OR gate 32. Also, when the control signal for the anti-skid control motor is being output from the anti-skid control circuit, the high-level control signal is output to the OR gate 32.
Is applied to the other input section. Therefore, when the electromagnetic solenoid 4 is on, and when the anti-skid control motor is on, or when both are on, a high level is output from the OR gate 32, whereby the power transistor 12 is switched on, The threshold value changing relay 10 is excited, and 4V, which is the criterion for canceling the anti-skid control, is changed to 3V, as in the case of FIGS.

As described above, during the anti-skid control, the load current flowing out of the battery 6 due to the driving of the anti-skid control motor or the like becomes larger than in the normal state. Therefore, when the outflow current due to the load is larger than the inflow current, the criterion for canceling the anti-skid control is changed downward, or when the inflow current amount is larger than the outflow current amount, the criterion is changed upward. In order to detect the outflow current or the inflow current due to the load, for example, a low-resistance shunt is inserted on the secondary side of the ignition switch 5 and the voltage drop generated in the shunt is detected. What is necessary is just to know the magnitude of the load current from the magnitude of. In each of the above embodiments, the relay 10 is used to change the criterion for canceling the anti-skid control. However, the relay may be switched by a motor or a solenoid.

[0031]

As described above, in the present invention, during braking or anti-skid control or the like, the threshold value for detecting an abnormality in the power supply voltage is changed to a low value. For power supply voltage that is likely to occur in the middle etc., the abnormality determination criteria are relaxed, so that an abnormality is not determined with a certain voltage drop, and it is not easy to shift to fail-safe processing, so stable control can be obtained Becomes Although the present invention has mainly described the anti-skid control in the case of sudden braking, it is also effective for traction control.

[Brief description of the drawings]

FIG. 1 is a control block diagram showing one embodiment of an anti-skid control device of the first invention.

FIG. 2 is a control block diagram showing one embodiment of the anti-skid control device of the second invention.

FIG. 3 is a control block diagram showing one embodiment of the anti-skid control device of the third invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wheel speed sensor 2 Anti-skid control circuit 3 Power transistor 4 Electromagnetic solenoid 5 Ignition switch 6 Battery 7 Stabilization circuit 8 Comparator 9 Comparator 10 Relay 11 Brake switch 12 Power transistor 13 Buffer 14 Power transistor 15 Alarm lamp 16 Power transistor 17 Relay 21 Latch circuit 31 Relay 32 OR gate 33 Power transistor 34 Relay

Continuation of front page (56) References JP-A-3-186466 (JP, A) JP-A-61-81262 (JP, A) JP-A-2-296569 (JP, A) JP-A-59-50711 (JP, A) JP-A-1-278882 (JP, A) JP-A-58-222792 (JP, A) JP-A-3-38265 (JP, U) JP-A-57-122448 (JP, U) JP-A 1-1116533 (JP, U) JP 4-71740 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) B60T 8/88-8/96 B60R 16/02 G08B 19 / 00-21/24

Claims (8)

(57) [Claims] 1. A threshold value for monitoring a power supply voltage abnormality is set, and when a power supply voltage abnormality is detected by comparison with the threshold value, a fail-safe operation such as returning to a normal braking state is performed. In the anti-skid control device which performs the processing, a brake detecting means for detecting that braking is being performed, and a function for detecting an abnormality of the power supply voltage when a detection output of the brake detecting means is obtained. An anti-skid control device comprising: threshold changing means for changing a threshold value. 2. The anti-static system according to claim 1, wherein said threshold value changing means decreases a threshold value in said power supply voltage abnormality detection by a predetermined value when a detection output of said braking detection means is obtained. Skid control device. 3. A threshold value for monitoring a power supply voltage abnormality is set, and when a power supply voltage abnormality is detected by comparing with the threshold value, fail-safe operation such as returning to a normal braking state is performed. An anti-skid control device configured to perform processing, comprising: anti-skid detection means for detecting that anti-skid control is being performed; and when the detection output of the anti-skid detection means is obtained, the power supply voltage is reduced. An anti-skid control device, comprising: threshold changing means for changing a threshold when an abnormality is detected. 4. The threshold value changing means according to claim 3, wherein said threshold value changing means lowers the threshold value in said power supply voltage abnormality detection by a predetermined value when the detection output of said anti-skid detecting means is obtained. Anti-skid control device. 5. A method for setting a threshold value for monitoring a power supply voltage abnormality, and for fail-safe operation such as returning to a normal braking state when a power supply voltage abnormality is detected by comparing with the threshold value. An anti-skid control device adapted to perform processing, a motor drive detecting means for detecting that an anti-skid control motor is being driven, and a solenoid for detecting that an electromagnetic solenoid for controlling brake fluid pressure is being energized. Energization detection means, and threshold change means for changing a threshold value when the power supply voltage is abnormally detected when a detection output of the motor drive detection means or the solenoid energization detection means is obtained. An anti-skid control device, characterized in that: 6. The threshold value changing unit according to claim 5, wherein the threshold value changing unit decreases the threshold value in the abnormality detection of the power supply voltage by a predetermined value when the detection output of the motor drive detection unit is obtained. Anti-skid control device. 7. A threshold value for monitoring an abnormality of a power supply voltage is set, and when an abnormality of the power supply voltage is detected by comparing with the threshold value, a fail-safe operation such as returning to a normal braking state is performed. In an anti-skid control device adapted to perform processing, an outflow current detection means for detecting an amount of current flowing from a power supply, an inflow current detection means for detecting an amount of current flowing into a power supply, and a current amount obtained by the current detection means And a threshold value changing means for changing a threshold value in the abnormality detection of the power supply voltage. 8. The threshold value changing means, when the outflow current amount is larger than the inflow current amount obtained by the current detection means, lowers the threshold value in the abnormality detection of the power supply voltage by a predetermined value, and 8. The anti-skid control device according to claim 7, wherein the threshold value is increased by a predetermined value when the amount of inflow current is larger than the amount of current.