JPH065933Y2 - Anti-skid control brake control mechanism - Google Patents

Description

TECHNICAL FIELD The present invention relates to an anti-skid control brake control mechanism applied to a four-wheel drive vehicle or the like.

In particular, in a four-wheel drive vehicle, since the front and rear restraint force of the drive system is exerted, there is a possibility that four-wheel simultaneous slip will occur during braking. The present invention relates to a mechanism for controlling an anti-skid control brake (ASB) by determining a low μ road surface or a high μ road surface.

2. Description of the Related Art Conventionally, a vehicle body may slip due to wheel locking during sudden braking. In particular, a four-wheel drive vehicle has a front-rear restraint force of the drive system, so that there is a possibility that four-wheel simultaneous slip may occur during braking. There was an anti-skid control brake (ASB) to prevent this, but this ASB was composed of parts such as a vehicle speed sensor, a computer and an actuator. However, the friction characteristics between the tires change depending on the road surface condition, and although the slip ratio is different between the high μ road surface and the low μ road surface, the road surface condition cannot be distinguished by the computer. However, that caused trouble. Therefore, in order to make the ASB controllable according to the road surface condition, a G sensor is also mounted.

In this type of G sensor, a long and short terminal is internally provided, and a sealed tube made of a glass tube containing a mercury ball is set upright at a certain inclination angle, and the mercury ball is brought into contact with the contact point of the long and short terminals to turn on. A switch part that turns on (ON) is formed. When the switch part is turned on, it is determined that the road surface is a low μ road such as an icy road. When the switch part is turned off (OFF), a high μ road surface such as an asphalt road is used. It is determined that there is. That is, the switch portion of the G sensor is turned on / off based on the vehicle deceleration during braking, and the ASB is controlled by determining whether the road surface is low μ road surface or high μ road surface.

FIG. 5 shows a flow chart of ASB control by the conventional G sensor. The ON / OFF state of the G sensor is input while the wheel speed during traveling is input. The on / off state of the G sensor is determined by the relationship between the vehicle body deceleration during braking and the angle of inclination of the closed pipe of the G sensor. However, when the switch of the G sensor is turned on, it is determined to be a low μ road surface, and when it is off, It is judged to be a high μ road surface. When it is determined that the road surface is low μ, the vehicle speed on the low μ road surface is calculated, the slip ratio is calculated, and the slip state is determined by the locked state of the wheels. Control of ASB is performed. Further, when it is determined that the road surface has a high μ road surface, the vehicle speed of the high μ road surface is calculated as in the low μ road surface state, and the slip ratio is calculated. It was the control.

In addition, when the judgment of the high μ road and the low μ road based on the signal from the G sensor is added, this means that when the braking force increases until the wheel lock tendency occurs and the anti-skid control is performed. The reason is that the deceleration generated in the vehicle is governed by the coefficient of friction between the wheels and the road surface.
That is, the phenomenon that the deceleration (signal from the G sensor) generated in the vehicle at the time of shifting to the anti-skid control is low on the low μ road and high on the high μ road is utilized, for example, Japanese Patent Publication No. 58-47381. Are known from.

The problem to be solved by the invention is that the switch part using the G sensor is turned on by contact with a mercury ball if the contacts of the long and short terminals are operating normally,
It was decided that it was a low μ road surface, and if it was not in contact, it was turned off and it was decided that it was a high μ road surface, but if there was a hindrance to the off operation, on a low μ road surface Despite this, the contact of the terminal continues to be turned off and it is determined that the road surface is high μ. Therefore, in such an off failure, the anti-skid control brake (AS
B) is inconvenient because it controls a large amount of slip. Even so, there was a means to detect that this off failure, so I could deal with it, but
In the case of an ON failure in which the contact of the switch terminal is fixed by some means, all road surfaces are judged to be low μ road surfaces, which is a malfunction, and a means for detecting the ON failure. Because there is no
The control of B is inconvenient because it causes a malfunction that is worse than the malfunction caused by determining that the low μ road surface is the high μ road surface.

In other words, regarding the off failure, even if the off state is caused by a large vehicle deceleration state, the G sensor that normally operates does not continue to be in that state for a long time. Therefore, the off state signal is transmitted for a certain period of time or more. When it became, it could be regarded as an off failure. However, the on-fault in which all road surfaces are judged to be low μ due to the contact sticking is high μ
Even though the vehicle slips on the road surface, it is regarded as the vehicle deceleration of the low μ road surface determination by the ASB control, and even if the ASB is operated because the vehicle deceleration is determined by the low μ road surface determination because the braking without slipping is performed. This is a big problem because there is no inconvenience that the control is performed only below the vehicle deceleration by the low μ road surface determination, and there is no means for detecting this even if there is an ON failure.

Therefore, an object of the present invention is to provide an anti-skid control brake control mechanism capable of ensuring stable performance even if an ON failure occurs in the G sensor.

Means for Solving the Problems The present invention was devised in view of the above circumstances, and a wheel speed sensor for detecting a wheel speed and a wheel speed sensor which is normally turned on and is turned off when a deceleration more than a predetermined amount acts on the vehicle body. A sensor, an actuator that adjusts the braking force acting on the wheel, and an output of each of the sensors to control the operation of the actuator. When the G sensor is on, the control for the low μ road is executed and the G sensor is also executed. In the anti-skid control brake control mechanism having a controller that executes control for high μ roads when is off, a plurality of G sensors are provided and the control is low only when all G sensors are on. An anti-skid control brake control mechanism characterized by being configured to execute control for a μ road.

According to the present invention, the controller executes the control for the low μ road only when all of the plurality of G sensors are turned on, so that even if one of the plurality of G sensors fails, the high μ
When braking on the road, the control for the high μ road is executed by turning off the other G sensors.

Therefore, the inconvenience caused by the ON failure of the G sensor can be eliminated, and the reliability of control is improved.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 shows a schematic structure of an anti-skid control brake (ASB) in a four-wheel drive vehicle (hereinafter referred to as a 4WD vehicle). The wheel speed sensor 1 detects the wheel speed, while the G sensor 3 detects the on / off state. These are input to the computer 2, the computer 2 calculates an appropriate slip ratio, and a command is issued to the actuator 4 so as to maintain it, and the actuator 4 which received the command increases or decreases the brake fluid pressure to change the ASB. The operation is controlled. In this ASB control, since the ON / OFF operation of the G sensor 3 influences the ASB control function, the present invention provides a function realizing means for the G sensor 3 to always operate normally.

FIG. 2 shows a flow chart in which two G sensors are used for ASB control to reduce the influence of on-state failure.
The figure shows a flow chart of ASB control in which an ON failure detection means is provided in addition to the two G sensors.

First, in FIG. 2, a wheel speed sensor 1 is used when a 4WD vehicle is running.
Detects the wheel speeds of the four wheels and the result is detected by computer 2
ASB control is performed in the state of being input to. Like this
Appropriate slip ratio for SB control However, since the vehicle body speed differs depending on the road surface condition, the vehicle body speed is optimized in order to maintain an appropriate slip ratio.

The vehicle speed with respect to the road surface state is detected by turning the G sensor on and off, and when it is on, it is determined to be a low μ road surface, and when it is off, it is determined to be a high μ road surface and is input to the computer.

However, if the G-sensor 3 fails, the high μ
Even if the road surface shifts to the road surface, the computer cannot make the determination.
Connect in series. Therefore, G sensor A or G sensor B
Even if one of the two is on-failed, if traveling braking is performed on a high μ road surface, the normal G sensor is turned off, the high μ road surface speed is calculated, and if the vehicle is not slipping due to wheel lock, The actuator is commanded to perform the ASB control for the high μ road surface so that the slip ratio becomes appropriate. If both G sensor A and G sensor B are turned on and it is determined that the road surface is low μ, this is input to the computer, the vehicle speed of the low μ road surface is calculated, and if the vehicle is slipping due to wheel lock, it is low. ASB control for μ road surface is performed.

Next, FIG. 3 is a flow chart of ASB control provided with an ON failure detection means of the G sensor in addition to the function of FIG. That is, by providing a means for detecting a failure of the G sensor in a state where the wheel speed is input to the computer, when the ON failure of the G sensor is detected, it is determined that the road surface is high μ if the ASB is operating. ASB for high μ road surface
If the control is executed and the ASB is not in operation, the ASB
Shut down control. Further, when the failure detecting means does not detect the ON failure of the G sensor, as in the embodiment of FIG.
As the ASB control for the road is executed, the low μ is mistaken for the high μ road.
There is no road ASB control.

4A and 4B show a structural example of a G sensor provided with a functional means for detecting an ON failure.

(A) is to internally provided the long and short terminals 31, further internally provided with short pin 34 at the upper end of the mercury ball 32 enclosed predetermined angle θ slanted glass tube 33 was, upper switch to lower the switch portion SW ₁ This is a G sensor structure that forms a part SW ₂ and detects an ON failure when both upper and lower switch parts SW ₁ and SW ₂ are turned on.

(B) shows a G sensor composition comprising a glass tube 33 having a long and short terminal 31 therein and a mercury ball 32 enclosed and tilted at a constant angle θ. When the ignition is turned on by a solenoid actuator or the like, the G sensor composition is tilted by α rotation. By doing so, it is a G sensor structure that detects that the switch SW _{1 that} is turned on by bringing the mercury ball 32 into contact with the contact of the terminal 31 is surely turned off and that there is no on failure.

Needless to say, the on-failure detecting means of the G sensor is not limited to the above-described two G sensor structures.

Effect of the Invention As a result of the above, according to the present invention, the anti-skid control brake control, which had been supported by the ON failure in the G sensor, operates normally unless all the G sensors are in the ON failure. Since the inconvenience associated with the ON failure of the vehicle is eliminated and the reliability of control is improved, it is possible to secure the directional stability and maneuverability of the vehicle.

[Brief description of drawings]

FIG. 1 is a schematic structural diagram of an anti-skid control brake in a 4WD vehicle. FIG. 2 is a flow chart of anti-skid control brake control using two G sensors of the present invention, and FIG. 3 is a flow chart of two G sensors.
It is a flowchart figure of the anti-skid control brake control which provided the ON failure detection means in addition to the sensor. FIG. 4 is a diagram showing a structural example in which a G sensor having an on-failure detection means is provided. (A) is a structural diagram in which an upper switch part is provided, and (B) is a tilted G sensor composition. It is a structural diagram to detect. FIG. 5 is a flowchart of conventional anti-skid control brake control. 1 ... Wheel speed sensor, 2 ... Computer, 3 ... G sensor, 4 ... Actuator, 31, 34 ... Terminal, 32 ...
Mercury ball, 33 …… Glass tube, SW ₁ …… Lower switch part, SW ₂
...... Upper switch part.

Claims (1)

[Scope of utility model registration request] 1. A wheel speed sensor for detecting a wheel speed, a G sensor which is normally turned on and which is turned off when a deceleration of a predetermined amount or more acts on a vehicle body, an actuator which adjusts a braking force acting on a wheel, and each of the above. A controller is provided which controls the operation of the actuator in response to the output of the sensor, executes the control for the low μ road when the G sensor is on, and executes the control for the high μ road when the G sensor is off. In the anti-skid control brake control mechanism, a plurality of the G sensors are provided, and the control is configured to execute the control for the low μ road only when all the G sensors are turned on. Anti-skid control Brake control mechanism.