JPH08327480A - Device for detecting abnormality of braking system - Google Patents

Abstract

PURPOSE: To detect the abnormality of a braking system by recognizing the effective state of the braking system. CONSTITUTION: Various kinds of abnormality of a drum brake 1 are detected by always recognizing the effective state of the brake 1 against a supplied pneumatic pressure P by directly detecting the braking torque F of the brake 1 by means of a braking torque detecting means 8 and, when the brake 1 is actuated, detecting the pneumatic pressure P supplied to an air chamber 4 by means of a pneumatic pressure sensor 10 and comparing the braking torque F with the pneumatic pressure P by means of a controller 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an abnormality detecting device for detecting an abnormality of a braking device by directly detecting a braking torque of the braking device.

[0002]

2. Description of the Related Art A general braking system for an automobile sends a fluid (for example, air) to a brake chamber through a brake valve which operates in conjunction with the depression of a brake pedal, and the brake shoe is driven by the air pressure sent to the brake chamber. Is operated to bring the brake shoe into contact with a rotating body that rotates integrally with the wheel to obtain a braking force by frictional force. Brake chambers are provided for each of the front, rear, left, and right wheels individually, and braking force is applied to each wheel individually according to the running state of the vehicle and the road surface condition, etc., to perform control to stabilize the behavior of the vehicle during braking. be able to. Also, especially for large vehicles and trailer vehicles, by applying braking force to each wheel individually according to the load capacity of the load,
It is possible to perform control such that the generated deceleration is constant regardless of the load amount.

Further, conventionally, control has been carried out in which the braking torque of the braking device is detected and a braking force is individually applied to each wheel in a state in which information on the braking torque is added to stabilize the behavior of the vehicle during braking. . A general braking torque detecting device, as disclosed in Japanese Patent Laid-Open No. 4-344437, detects a deflection due to a reaction force of a pressing force of a friction pad of a disc brake, and detects a braking torque based on the detected deflection. I am trying. Further, as a braking torque detecting device, Japanese Patent Laid-Open No.
As shown in Japanese Patent No. 123665, a support member is provided between the caliper of the disc brake and the knuckle arm,
There is known a device that detects a braking torque by detecting a displacement of the support member during braking. Although all of the above-described braking torque detection devices are applied to the disc brake, the braking torque can be detected similarly in the drum brake.

[0004]

By the way, when the braking force of the wheels is reduced due to some cause, particularly when the braking force of one system is reduced in one wheel or a large vehicle or trailer vehicle, the braking force is reduced. It is difficult for the driver to experience the behavior and the feeling of braking. Since large vehicles and trailer vehicles have a large number of wheels and also use auxiliary brakes, it is very difficult to recognize the reduction of the braking force of the wheels. If the detection of abnormality in the braking force is delayed and the braking device is continuously used as it is, there is a possibility that the brake may be one-sided or faded.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an abnormality detecting device for a braking device that can detect an abnormality of the braking device by grasping the state of the braking force of each wheel. To do.

[0006]

The structure of the present invention for achieving the above-mentioned object is to apply a braking torque detecting means for detecting a braking torque of a braking device for obtaining a braking force by a fluid pressure, and a braking torque detecting means for the braking device at the time of braking. The fluid pressure detecting means for detecting the fluid pressure is compared with the braking torque detected by the braking torque detecting means and the fluid pressure detected by the fluid pressure detecting means, and the braking torque corresponding to the fluid pressure is predetermined. And a control device for determining an abnormality of the braking device when the value is equal to or less than a value.

Further, the braking device is a drum brake that obtains a braking force by bringing the brake shoe into contact with the drum by air pressure, and the fluid pressure detecting means detects the air pressure for operating the brake shoe. It is an air pressure sensor, and the control device has a function of determining an abnormality of the drum brake when the ratio of the braking torque to the air pressure becomes equal to or less than an allowable value. Further, it is characterized in that an alarm means is provided for notifying the abnormality determination when the controller determines the abnormality of the braking device.

[0008]

The braking torque of the braking device obtained by the fluid pressure is detected by the braking torque detecting means, and the fluid pressure at this time is detected by the fluid pressure detecting means. The braking torque and the fluid pressure are compared by the control device, and in the control device, when the braking torque with respect to the fluid pressure is equal to or less than a predetermined value,
That is, when the braking torque is low despite the sufficient fluid pressure, it is determined that the braking device is abnormal.

Further, the braking torque of the drum brake obtained by the air pressure is detected by the braking torque detecting means, and the air pressure at this time is detected by the air pressure sensor. The braking torque and the air pressure are compared by the control device, and in the control device, when the ratio of the braking torque to the air pressure is equal to or less than the allowable value, that is, when the braking torque is low in spite of the sufficient air pressure, It is judged that the drum brake is abnormal. Further, when the abnormality is determined, the alarm means notifies that there is an abnormality.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a schematic structure of an abnormality detecting device for a braking device according to an embodiment of the present invention, and FIG. 2 shows a flowchart for detecting an abnormality in a control device. In the illustrated example, a drum brake is shown as the braking device for explanation, but the present invention is also applicable to a disc brake as the braking device.

As shown in FIG. 1, a drum brake 1 as a braking device applies a braking force to a wheel by pushing a pair of brake shoes 3 into contact with a drum 2 which rotates integrally with a wheel (not shown). generate. The pair of brake shoes 3 is spread by the cylinder 5 driven by the air supplied to the brake chamber 4. Air is supplied to the brake chamber 4 from an air tank 6, and the air from the air tank 6 is supplied to the brake chamber 4 via a brake valve 7 that operates in conjunction with depression of a brake pedal. Therefore, when the driver depresses the brake pedal, the brake valve 7 operates and air is supplied to the brake chamber 4, and the pair of brake shoes 3 is spread by the cylinder 5 to rotate the drum 2, that is, the wheel. The rotation stops.

The drum brake 1 is provided with a braking torque detecting means 8 for detecting the braking torque F of the drum brake 1 during braking. As the braking torque detecting means 8, for example, a strain gauge is attached to an anchor bracket fixed to an axle on the vehicle body side, and the strain of the anchor bracket corresponding to the rotational force received from the drum 2 via the brake shoe 3 is directly converted into an electric signal. The one that is taken out to detect the braking torque is used. Incidentally, as the means for detecting the braking torque, another detection means such as a braking torque detecting means for detecting the deflection due to the reaction force of the pressing force of the brake shoe 3 and detecting the braking torque by the detected deflection is used. It is also possible.

The braking torque F detected by the braking torque detecting means 8 during braking is input to a controller 9 as a control device. On the other hand, an air pressure sensor 10 is provided in the air pipe on the upstream side of the brake chamber 4, and the pressure of the air supplied to the brake chamber 4 is detected. The braking air pressure P detected by the air pressure sensor 10 is the controller 9
And the controller 9 compares the air pressure P with the braking torque F. The controller 9 has a function of determining an abnormality of the drum brake 1 when the ratio (F / P) of the braking torque F to the air pressure P becomes equal to or less than the allowable value A. That is, when the braking torque F is low despite the supply of the sufficient air pressure P, it is determined that the effectiveness of the drum brake 1 is reduced and an abnormality has occurred.

Braking torque detecting means 8 and air pressure sensor 1
0 is provided for each wheel, and in the case of a large-sized vehicle, it is provided for each wheel or each wheel system, and the occurrence of abnormality of the drum brake 1 is individually judged. When the controller 9 determines that the abnormality of the drum brake 1 has occurred, an alarm lamp 11 as an alarm means is turned on to notify the driver of the abnormality of the drum brake 1.

The function of detecting an abnormality in the controller 9 will be described with reference to FIG. The braking air pressure P detected by the air pressure sensor 10 is read, and it is determined whether the air pressure P is a positive value, that is, whether air is being supplied to the brake chamber 4. When air is supplied to the brake chamber 4, the braking torque F detected by the braking torque detecting means 8 is read. When the braking torque F is read, the ratio of the braking torque F to the air pressure P (F
/ P) is less than or equal to the allowable value A. When the ratio (F / P) of the air pressure P and the braking torque F is less than or equal to the allowable value A,
Although the brake chamber 4 is supplied with a sufficient air pressure P, the braking torque F of the drum brake 1 is low, that is, the effectiveness of the drum brake 1 is reduced. It is determined that an abnormality has occurred in the drum brake 1, and the alarm lamp 11 is turned on.
The allowable value A is set to a value such that an abnormality is not judged when the braking torque F changes due to road surface conditions such as the road surface μ.

The abnormality of the drum brake 1 can be estimated in various situations according to the ratio of the air pressure P and the braking torque F. In other words, depending on the degree of decrease in the effectiveness of the drum brake 1,
Is it a situation of fade or vapor lock phenomenon, or a situation where the gap of the brake shoe 3 is too large?
It is possible to detect whether the brake pad of the brake shoe 3 is in bad contact or worn, or whether the body of the drum brake 1 is damaged or the system of the braking device itself is damaged. it can. That is, various situations can be detected by storing a plurality of types of allowable values A in the controller 9 and detecting abnormalities stepwise.

The above-mentioned abnormality detecting device for the braking device directly detects the braking torque F of the drum brake 1 by the braking torque detecting means 8 and at the time of braking the drum brake 1
The air pressure P supplied to the air pressure sensor 10 is detected by the air pressure sensor 10, and the controller 9 compares the braking torque F with the air pressure P to constantly grasp the effect of the drum brake 1 on the supplied air pressure P. can do. For this reason, for example, even in the case of the drum brake 1 of a vehicle in which it is difficult to experience a reduction in braking effectiveness, such as in a large vehicle having many wheels, it is possible to detect an abnormality early.
As a result, when an abnormality of the drum brake 1 is detected, it is possible to prevent the drum brake 1 from falling into a dangerous state by cooling the device or using the auxiliary brake frequently.

[0018]

An abnormality detecting device for a braking device according to the present invention includes a braking torque detecting means for detecting a braking torque of the braking device for obtaining a braking force by a fluid pressure, and detects a fluid pressure acting on the braking device during braking. A fluid pressure detecting means is provided, and a control device for comparing the braking torque at the time of braking with the supplied fluid pressure to determine an abnormality of the braking device when the braking torque is low despite the sufficient fluid pressure is provided. Therefore, it is possible to always grasp the state of effectiveness of the braking device with respect to the supplied fluid pressure. As a result, it becomes possible to detect the abnormality of the braking device by directly detecting the braking torque, and it is possible to prevent the braking device from falling into a dangerous state.

Further, the abnormality detecting device for the braking device of the present invention is provided with a braking torque detecting means for detecting the braking torque of the drum brake which obtains the braking force by the air pressure, and at the same time, detects the air pressure supplied to the drum brake during braking. It is equipped with an air pressure sensor to detect, and a control device to judge the abnormality of the drum brake when the braking torque is low with respect to the supplied air pressure. You can figure it out. As a result, it becomes possible to detect various abnormalities of the drum brake by directly detecting the braking torque, and it is possible to prevent the drum brake from falling into a dangerous state.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an abnormality detection device for a braking device according to an embodiment of the present invention.

FIG. 2 is a flowchart of abnormality detection in the control device.

[Explanation of symbols]

 1 Drum Brake 2 Drum 3 Brake Shoe 4 Brake Chamber 5 Cylinder 6 Air Tank 7 Brake Valve 8 Braking Torque Detecting Device 9 Controller 10 Air Pressure Sensor 11 Alarm Lamp

Claims (3)

[Claims] 1. A braking torque detecting means for detecting a braking torque of a braking device for obtaining a braking force by a fluid pressure, and a fluid pressure detecting means for detecting a fluid pressure acting on the braking device during braking.
Abnormality of the braking device when the braking torque detected by the braking torque detecting means and the fluid pressure detected by the fluid pressure detecting means are compared and the braking torque corresponding to the fluid pressure becomes a predetermined value or less. An abnormality detection device for a braking device, comprising: 2. The braking device is a drum brake that obtains a braking force by bringing a brake shoe into contact with a drum by air pressure, and a fluid pressure detecting means detects an air pressure for operating the brake shoe. An air pressure sensor, wherein the control device has a function of determining an abnormality of the drum brake when the ratio of the braking torque to the air pressure is below an allowable value.
An abnormality detection device for a braking device according to item 1. 3. The abnormality detecting device for a braking device according to claim 1, further comprising alarm means for notifying the abnormality determination when the controller determines that the braking device is abnormal.