JPH0217385B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an antilock braking system for a vehicle, particularly a braking force applying system that applies braking force to front wheels and rear wheels, and a braking force applying system that applies braking force to the front wheels when the braking force to the front wheels is too large. A front wheel antilock control device that suppresses power, and a rear wheel antilock control device that is independent of the front wheel antilock control device and suppresses the braking force to the rear wheels when the braking force to the rear wheels is too large. The present invention relates to an anti-lock braking device for four-wheeled vehicles of the same type.

Conventionally, in this type of anti-lock braking device, when the anti-lock control device fails, its control function is completely disabled, so that the anti-lock braking device operates as a normal braking device without an anti-lock control function. However, with conventional safety devices, if either the front or rear wheel antilock control device fails and loses its braking force suppression function, , the other anti-lock control device is not configured to disable the other anti-lock control device in the normal state, so that the other anti-lock control device continues to be in the activated state. Therefore, if the driver applies excessive braking force especially when the rear wheel anti-lock control device is in the above-mentioned failure state, the front and rear wheels, which are originally different due to the difference in braking load distribution, are more likely to lock up. In other words, while the front wheels are strongly braked without locking up, the rear wheels tend to lock up early, which poses a problem in that the steering stability of the vehicle deteriorates.

The present invention can solve the above-mentioned problem when the rear wheel antilock control device fails, and moreover, if the front wheel antilock control device fails while the braking force is being suppressed, the operation of the control device is immediately disabled. To provide an anti-lock braking device for a four-wheeled vehicle, which has high braking efficiency and has a simple structure, which can contribute to securing braking force and improving steering stability by making it possible to improve the braking force.

In order to achieve this object, the present invention provides a braking force application system that applies braking force to the front wheels and rear wheels, and a front wheel system that suppresses the braking force to the front wheels when the braking force to the front wheels is too large. An antilock control device for a four-wheeled vehicle, comprising an antilock control device and a rear wheel antilock control device independent from the front wheel antilock control device, which suppresses the braking force to the rear wheel when the braking force to the rear wheel is too large. In the braking system, a front wheel safety device immediately shuts off the operating source of the front wheel antilock control device when the front wheel antilock control device fails while the braking force is being suppressed, and the rear wheel antilock control device includes The vehicle is characterized by comprising a rear wheel safety device that suppresses the braking force to the rear wheels for a predetermined period of time each time the braking force to the rear wheels becomes too large when the brake force suppressing function is lost.

According to the present invention, the front wheel antilock control device and the rear wheel antilock control device operate independently of each other, and the front wheel antilock control device for the front wheels, which generally has a relatively large distribution of braking force, suppresses the braking force. In the event of a failure, the front wheel safety device completely disables the front wheel anti-lock control device and secures braking force for the front wheels.
In addition, if the rear wheel anti-lock control device for the rear wheels, which generally has a relatively small distribution of braking force, fails without losing its braking force suppression function, the rear wheel safety device will switch to the rear wheel anti-lock control device. In turn, the steering stability of the vehicle is maintained by suppressing excessive braking force on the rear wheel side.

The anti-lock braking device includes a braking force transmission device that transmits braking force and applies braking force to the wheels;
When the braking force applied to the wheels by this braking force transmitting device is too large, an anti-lock control device acts on the braking force transmitting device to suppress the braking force based on preselected control input factors. Equipped with. Anti-lock control devices usually use a fluid, such as hydraulic oil, as a control pressure transmission medium, and such fluid is introduced into a control pressure acting chamber through a pressure guiding valve, and the control pressure is applied through a discharge pressure valve. Emitted from indoors. The pressure impulse valve and the exhaust pressure valve are each operated by an electromagnetic actuator.The electromagnetic actuator for the pressure impulse valve opens the impulse valve when energized and closes the impulse valve when it is not energized. The electromagnetic actuator closes the exhaust pressure valve when energized, and opens the exhaust pressure valve when not energized. Therefore, when both the electromagnetic actuator for the pressure guiding valve and the electromagnetic actuator for the exhaust pressure valve are energized, the amount of fluid in the control pressure action chamber continues to increase, and as a result, the braking force increases regardless of the driver's will. reduced. In addition, if the electromagnetic actuator for the pressure guiding valve is not energized and only the electromagnetic actuator for the exhaust pressure valve is energized, the fluid in the control pressure action chamber will be in a confined state, and as a result, the braking force will vary depending on the driver's will. remains constant regardless of Furthermore, when both the electromagnetic actuator for the pressure guiding valve and the electromagnetic actuator for the exhaust pressure valve are not energized, the fluid in the control pressure action chamber is in a state where it can be freely discharged, and as a result, the braking force is controlled according to the driver's will. Therefore, it can be increased.

Each electromagnetic actuator receives an output signal from an antilock control circuit that generates a control output signal by performing arithmetic processing based on preselected control input factors such as vehicle speed, wheel speed increase/decrease, and wheel slip rate. Therefore, energization is controlled.

The operation of the safety device in the present invention can be implemented in software using a microcomputer, but it can also be implemented using hard logic circuits.

Hereinafter, specific examples of circuits that can be used in implementing the present invention will be described.

First, in FIG. 1, a wheel speed detector 101 for the right front wheel and a wheel speed detector 102 for the left front wheel are as follows.
The circumferential speed of each corresponding front wheel is detected in the form of a pulse signal, and these output signals are set at a frequency of -
It is sent to voltage converters 103 and 104. The output signals of the frequency-voltage converters 103 and 104 are respectively sent to the front wheel anti-lock control circuit 105.
After performing arithmetic processing and judgment based on various control factors as described below, an output signal for antilock control is sent to the front wheel pressure guiding valve actuating device 106 and the front wheel exhaust pressure valve actuating device 107. Front wheel antilock control circuit 105, front wheel pressure guiding valve actuation device 10
6 and the front wheel exhaust pressure valve operating device 107 cooperate with each other to constitute the front wheel antilock control device of the present invention.

Next, the front wheel antilock control device will be explained in more detail. The front-stage signal processing section 110 of the front wheel anti-lock control circuit 105 performs preselected types of control such as vehicle speed, wheel increase/decrease speed, wheel slip rate, etc. based on wheel speed signals obtained from the wheel speeds of the left and right front wheels. After the control factors are calculated and a judgment is made according to preset judgment criteria based on these control factors, the output section 111 outputs a pressure valve intermittent operation signal, and the output section 112 outputs a pressure valve intermittent operation signal. A pressure guiding valve continuous activation signal is sent out. At this time, the pressure impulse valve intermittent operation signal sent from the output section 111 is a signal for controlling the pressure impulse valve to gradually increase the control pressure by repeatedly opening and closing the pressure impulse valve intermittently, and
The continuous pressure valve operation signal sent from the output part 112 is sent to the oscillator 113 only when the pressure valve continuous operation signal is not sent from the output part 112, whereas the pressure valve continuous operation signal sent from the output part 112 is controlled by continuously opening the pressure valve. This is a signal for controlling the pressure to increase instantaneously, and is sent to the OR circuit 114 together with the output signal of the oscillator 113. And this OR circuit 1
The output signal of 14 is sent to an AND circuit 115.

In addition, the output unit 116 outputs a front wheel side vehicle speed response for controlling such that the control pressure can be increased only when the vehicle body speed estimated based on the circumferential speed of the left and right front wheels is equal to or higher than a preset speed. A signal is sent out, and this front wheel side vehicle speed response signal is sent to a pair of AND circuits 115 and 125.

Further, the output section 121 outputs an intermittent operation signal for the exhaust pressure valve, and the output section 122 outputs a continuous operation signal for the exhaust pressure valve. At this time, the exhaust pressure valve intermittent operation signal sent from the output section 121 is
This is a signal for controlling the control pressure to gradually decrease by repeatedly opening and closing the exhaust pressure valve intermittently, and only when the exhaust pressure valve continuous operation signal is not sent from the output section 122, the oscillator 12
On the other hand, the exhaust pressure valve continuous operation signal sent from the output section 122 is a signal for controlling the exhaust pressure valve to continuously close and prevent the control pressure from decreasing. It is sent to the OR circuit 124 together with the output signal. The output signal of this OR circuit 124 is then sent to an AND circuit 125.

The pair of AND circuits 115 and 125 are connected to a rear wheel antilock control circuit 20, which will be described later.
Control pressure is controlled so that the control pressure can be increased only when the signal sent from the output section 216 of No. 5, that is, the vehicle speed estimated based on the circumferential speed of the left and right rear wheels, is equal to or higher than a preset speed. The rear wheel side vehicle speed response signal for this purpose is also received as an input signal.

After the output signal of the AND circuit 115 is inverted, it is sent to the base of the power transistor 133 of the front wheel pressure control valve operating device 106 via the output section 131 of the front wheel antilock control circuit 105. The emitter side of the power transistor 133 is connected to a battery power source 132, and the collector side is connected to a front wheel pressure guiding valve electromagnetic actuator 134.

After the output signal of the AND circuit 125 is inverted, it is sent to the base of the power transistor of the front wheel exhaust valve operating device 107 via the output section 141 of the front wheel antilock control circuit 105. The circuit configuration of this front wheel exhaust pressure valve actuating device 107 is basically the same as the circuit configuration of the front wheel pressure guiding valve actuating device 106, so illustration thereof is omitted. However, the emitter side of the power transistor of the front wheel exhaust pressure valve actuating device 107 is connected to the battery power source 132, while the collector side is connected to the front wheel exhaust pressure valve electromagnetic actuator.

The wheel speed detector 201 for the right rear wheel and the wheel speed detector 202 for the left rear wheel each detect the circumferential speed of the corresponding rear wheel in the form of a pulse signal, and send these output signals to the frequency-voltage converter 203, respectively. ,2
Send to 04. Each frequency-voltage converter 203, 20
The output signals of 4 are respectively sent to the rear wheel antilock control circuit 205, which, like the front wheel antilock control circuit 105, performs arithmetic processing and judgment based on various control factors. After performing this, an output signal for anti-lock control is sent to the rear wheel pressure guiding valve actuating device 206 and the rear wheel exhaust pressure valve actuating device 207. The rear wheel anti-lock control circuit 205, the rear wheel pressure guiding valve actuating device 206, and the rear wheel exhaust pressure valve actuating device 207,
They cooperate with each other to constitute the rear wheel antilock control device of the present invention.

Next, the rear wheel antilock control system will be explained in more detail. Anti-lock control circuit 2 for rear wheels
In the pre-stage signal processing unit 210 of 05, preselected types of control factors such as vehicle speed, wheel speed increase/decrease, and wheel slip rate are calculated based on the wheel speed signals obtained from the wheel speeds of the left and right rear wheels. Based on these control factors, judgments are made according to preset criteria, and then
The output section 211 outputs a pressure guiding valve intermittent operation signal, and the output section 212 outputs a pressure guiding valve continuous operation signal. At this time, the pressure impulse valve intermittent operation signal sent from the output section 211 is a signal for controlling the pressure impulse valve to gradually increase the control pressure by repeatedly opening and closing the pressure impulse valve intermittently. Whereas the continuous actuation signal is sent to the oscillator 213 only when the continuous actuation signal is not being sent out, the pressure valve continuous actuation signal sent from the output section 212 continuously opens the pressure valve and instantly increases the control pressure. This signal is sent to the OR circuit 214 together with the output signal of the oscillator 213. The output signal of this OR circuit 214 is then sent to an AND circuit 215.

Further, the output section 221 outputs an intermittent operation signal for the exhaust pressure valve, and the output section 222 outputs a continuous operation signal for the exhaust pressure valve. At this time, the exhaust pressure valve intermittent operation signal sent from the output section 221 is
This is a signal for controlling the control pressure to gradually decrease by repeatedly opening and closing the exhaust pressure valve intermittently, and only when the exhaust pressure valve continuous operation signal is not sent from the output section 222, the oscillator 22
On the other hand, the exhaust pressure valve continuous operation signal sent from the output section 222 is a signal for controlling the exhaust pressure valve to continuously close and prevent the control pressure from decreasing. It is sent to the OR circuit 224 together with the output signal. The output signal of this OR circuit 224 is then sent to an AND circuit 225.

Furthermore, the output unit 216 outputs rear wheel output for controlling the control pressure such that the control pressure can be increased only when the vehicle body speed estimated based on the peripheral speed of the left and right rear wheels is equal to or higher than a preset speed. A side vehicle speed response signal is sent out, and this rear wheel side vehicle speed response signal is sent to a pair of AND circuits 115, 125 of the front wheel antilock control circuit 105 and a pair of AND circuits 215, 225 of the rear wheel antilock control circuit 205.
are sent to each.

After the output signal of the AND circuit 215 is inverted, it is sent to the base of the power transistor 233 of the rear wheel pressure guiding valve operating device 206 via the output section 231 of the rear wheel antilock control circuit 205. The emitter side of the power transistor 233 is connected to the battery power source 232, and the collector side is connected to the rear wheel pressure guiding valve electromagnetic actuator 234.

Further, the output signal of the AND circuit 225 is inverted and then passed through the output section 235 of the rear wheel antilock control circuit 205 to the rear wheel exhaust pressure valve operating device 207.
is sent to the base of the power transistor 237.
The emitter side of the power transistor 237 is connected to a battery power source 236, and the collector side is connected to a rear wheel exhaust valve electromagnetic actuator 238.

Next, the front wheel safety device will be explained. This front wheel safety device is a front wheel pressure valve actuation device 106.
a front wheel pressure guiding valve side failure detection device 108 that operates using the collector side output signal of the power transistor 133 as an input signal, and a front wheel exhaust pressure valve actuating device 107.
A front wheel exhaust pressure valve side failure detection device 109 which operates using the collector side output signal of the power transistor as an input signal, a front wheel pressure guide valve side failure detection device 108 and a front wheel exhaust pressure valve side failure detection device 109.
An OR circuit 301 that receives an output signal from the OR circuit 301 operates in response to the output signal of this OR circuit 301 to abnormally suppress the braking force in either the front wheel pressure guide valve actuating device 106 or the front wheel exhaust pressure valve actuating device 107. When it is determined that the front wheel anti-lock control device has failed due to the continued condition, the front wheel pressure guiding valve actuating device 106 and the front wheel exhaust pressure valve actuating device 10
7, and a safety relay 302 that shuts off the battery power supply 132 that is the operating source of 7.

The circuit configuration of the front wheel exhaust pressure valve side failure detection device 109 is basically the same as the circuit configuration of the front wheel pressure guide valve side failure detection device 108, but illustration thereof is omitted. Therefore, the front wheel pressure guiding valve side failure detection device 108 will be described in more detail below.

When the front wheel pressure guiding valve electromagnetic actuator 134 is energized, the one-shot circuit 135 is activated at the same time, and its output signal is inverted and sent to the AND circuit 136. The output signal of the power transistor 133 is also directly sent to an AND circuit 136, and the operation of the one shot circuit 135 causes the AND circuit 136 to operate the front wheel pressure induction valve electromagnetic actuator 134.
The power transistor 133 does not generate an output signal until a preset time has elapsed after the power transistor 133 is energized, and if the power transistor 133 continues to generate an output signal even after the preset time has elapsed, the front wheel antilock control device takes control. OR circuit 137 and OR circuit 3 are determined to have failed with the power still suppressed.
A signal is sent to the safety relay 302 through 01 to cut off the battery power supply 132.

The output signal of the power transistor 133 is further sent in an inverted state to a retrigger type one-shot circuit 138 and also directly to an AND circuit 137. One shot circuit 13
8 always generates an output signal while the pulse interval of the output signal of the power transistor 133 is equal to or less than a preset interval, and as a result, the AND circuit 139 generates the output signal as the output signal of the power transistor 133 is interrupted. and sends its output signal to the counter circuit 140. Counter circuit 140
counts the number of pulses of the input signal, and when the number of pulses reaches a preset value, it is determined that the front wheel antilock control device has failed while suppressing the braking force, and the OR circuit 137 and the OR circuit 137 and A signal is sent to the safety relay 302 through the circuit 301 to cut off the battery power supply 132.

The output signal of the one-shot circuit 138 is inverted and sent to the counter circuit 140, so that
The counter circuit 140 is placed in a reset state, and if the pulse interval of the output signal of the power transistor 133 exceeds the set interval before the number of pulses counted by the counter circuit 140 reaches the set value, one shot is activated. The output signal of circuit 138 is interrupted, and as a result, counter circuit 140 is placed in a reset state so that it does not generate an output signal and antilock control continues.

Next, the rear wheel safety device 250 will be explained. The output signal of each frequency-voltage converter 203, 204 is transmitted to a corresponding comparator 251, 252, respectively.
Here, when the value of the input signal of each comparator 251, 252 is smaller than the preset value υ ₀ , the corresponding comparator 251, 252
Each output signal is sent to an AND circuit 256 through an OR circuit 253. Further, when the vehicle speed estimated based on the circumferential speed of the front wheels is higher than a certain speed, the output section 116 of the front wheel antilock control circuit 105
A signal is sent to terminal 116', and
When the vehicle speed estimated based on the circumferential speed of the rear wheels is higher than a certain speed, the rear wheel antilock control circuit 2 is activated.
A signal is sent from the output section 216 of 05 to the terminal 216', and the signals sent to each terminal 116', 216' are sent to the AND circuit 256 through the OR circuit 254, respectively. Further, when the driver starts a braking operation, a signal is sent to a terminal 255, and the signal sent to this terminal 255 is sent to an AND circuit 256.

Therefore, the AND circuit 256 locks the rear wheels when the circumferential speed of one of the left and right rear wheels falls below the reference speed when a braking operation is performed when the vehicle speed is above a certain speed. It is determined that the output signal has been reached, and the output signal is sent to the one-shot circuit 257.
send to When the one-shot circuit 257 receives a signal from the AND circuit 256, it generates an output signal for a preset time. The output signal of the one-shot circuit 257 is inverted by an inverting circuit 258 and sent to the bases of a pair of transistors 260 and 261. Each transistor 260, 26
The emitter side of the transistor 260 is connected to the battery power supply 259, and the collector side of the transistor 260 is connected to the battery power supply 259.
The collector side of the transistor 261 is connected to the rear wheel pressure guiding valve electromagnetic actuator 234.
It is connected to the rear wheel exhaust pressure valve electromagnetic actuator 238.

FIG. 2 shows the magnitude of the braking force E on the rear wheel when the rear wheel safety device 250 in FIG. 1 is activated;
Braking force suppression signal F for energizing each electromagnetic actuator 234, 238, rear wheel circumferential speed V _w and vehicle speed V
An example of a correlation diagram of the time course of is shown. When braking is started at time t ₀ , the circumferential speed V _W of the rear wheels decreases as the magnitude E of the braking force increases,
At time _t1 , the rear wheels become locked, but immediately a braking force suppression signal F is generated and the braking force is suppressed. As the magnitude of the braking force E decreases, the rear wheel comes out of the locked state at time _t2 and its circumferential speed decreases.
_VW is recovering. The braking force disappears at time _t3 , but when the set time elapses after time _t1 and reaches time _t4 , the braking force suppression signal F disappears, so the braking force recovers again, and its magnitude E is continues to increase, but the circumferential speed of the rear wheel V _W decreases again as a result.
At time _t5 , the rear wheels are locked again,
As a result, the control force suppression signal F is immediately generated. Thereafter, the same process is repeated one after another, and the vehicle speed V gradually decreases.

As described above, according to the present invention, there is provided a braking force applying system that applies braking force to the front wheels and rear wheels, and a front wheel antilock control that suppresses the braking force to the front wheels when the braking force to the front wheels is too large. and a rear wheel antilock control device independent from the front wheel antilock control device, which suppresses the braking force to the rear wheel when the braking force to the rear wheel is too large. and a front wheel safety device that immediately shuts off the operating source of the front wheel antilock control device when the front wheel antilock control device fails while the braking force is being suppressed; The anti-lock control device for the rear wheels is provided with a rear wheel safety device that suppresses the braking force to the rear wheels for a predetermined period of time each time the braking force to the rear wheels is too large when the braking function is lost. When the rear wheel safety device loses its braking force suppression function, the rear wheel safety device can suppress the braking force on the rear wheels for a predetermined period of time each time the braking force on the rear wheels becomes too large; Therefore, it is possible to reduce the difference in the likelihood of locking between the front and rear wheels as much as possible, thereby reliably avoiding a situation where only the rear wheels lock early, thereby ensuring the steering stability of the vehicle. obtain. Moreover, as mentioned above, there is no need to specifically disable the operation of the front wheel antilock control device in order to avoid premature locking of only the rear wheels, so an appropriate braking force is applied to both the rear wheels and the front wheels. It is possible to improve braking efficiency, and it is also possible to reduce the difference in performance between when the rear wheel antilock control device is malfunctioning as described above and when it is normal, thereby reducing the driver's anxiety. There is no risk of giving. Furthermore, the rear wheel safety device merely functions to suppress the braking force on the rear wheels for a predetermined period of time each time the braking force on the rear wheels is too large, so the circuit is more complex than a normal anti-lock control device. The configuration can be simplified and can contribute to cost reduction.

On the other hand, even if the front wheel antilock control device fails while the braking force is being suppressed, the operation of the front wheel antilock control device can be immediately disabled and the braking condition can be switched to the normal braking condition, so the braking load distribution is large. It is possible to always secure the necessary braking force for the front wheels.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of an anti-lock braking system with safety devices for front and rear wheels according to an embodiment of the present invention, and FIG. 2 is a diagram illustrating changes over time to explain an example of the operation of the rear wheel safety device. 105... Front wheel antilock control circuit constituting the front wheel antilock control device, 106... Front wheel pressure guiding valve actuating device, 107... Front wheel exhaust pressure valve actuating device, 108... Front wheel constituting the front wheel safety device. 109...Failure detection device on the exhaust pressure valve side for the front wheels, 132...Battery power source forming the operating source of the antilock control device for the front wheels, 205...Constituting the antilock control device for the rear wheels. anti-lock control circuit for rear wheels, 206
... Pressure guiding valve actuation device for the same rear wheel, 207 ... Rear pressure valve actuation device, 250 ... Safety device for the rear wheel,
301...OR circuit configuring the front wheel safety device,
302...Same safety maintenance relay.

Claims (1)

[Claims] 1. A braking force application system that applies braking force to the front wheels and rear wheels, and front wheel antilock control devices 105 to 107 that suppress the braking force to the front wheels when the braking force to the front wheels is too large;
For a four-wheel vehicle, the vehicle is equipped with a rear wheel antilock control device 205 to 207 independent of the front wheel antilock control devices 105 to 107, which suppresses the braking force to the rear wheel when the braking force to the rear wheel is too large. In the anti-lock braking device, the front wheel anti-lock control device 105-1
07 fails while the braking force is being suppressed, the front wheel antilock control device 1 is immediately activated.
When the front wheel safety devices 108, 109, 301, 302 that cut off the operating source of the brakes 05 to 107 and the rear wheel antilock control devices 205 to 207 fail to the point where they lose their braking force suppression function, An anti-lock braking system for a four-wheel vehicle, comprising a rear wheel safety device 250 that suppresses the braking force on the rear wheels for a predetermined period of time each time the braking force is too large.