JPH0620874B2 - Breaking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a hydraulic control valve for changing the air pressure of an air spring for a vehicle body suspension in order to change the braking force of a rear wheel brake according to the loaded weight of a vehicle. In particular, the present invention relates to a brake device capable of ensuring safety even when the air pressure of the air spring becomes an abnormal pressure.

[Conventional technology]

Generally, in a brake device of a vehicle, it is required to apply an appropriate braking force according to the weight of the vehicle. That is, since the load applied to the rear wheel side greatly changes between when the vehicle is loaded and when the vehicle is empty, unless the braking force is variably controlled according to the weight of the vehicle, the braking force becomes insufficient when the vehicle is loaded, and the empty vehicle At times, the braking force becomes excessive and the rear wheel side is easily locked.

For this reason, various braking devices have been proposed so far that the braking force of the rear wheel brakes can be variably controlled according to the weight of the vehicle.

For example, in the brake device disclosed in Japanese Patent Application Laid-Open No. 60-82471, a control valve for controlling the braking force of the rear wheel brakes by adjusting the air pressure of a body suspension air spring that adjusts the vehicle height according to the loaded weight of the vehicle. In order to change the braking force of the rear wheel brake by taking out the change of the air pressure of the air spring as the change of the vehicle load by the control valve, it is possible to always apply an appropriate braking force to the rear wheel side. I have to.

[Problems to be solved by the invention]

However, in the above-described conventional technique, when the device for supplying and exhausting the air pressure to the air spring for vehicle body suspension fails, the air pressure of the air spring becomes abnormally high or low, and the vehicle height can be adjusted. If it becomes impossible and when it becomes high, there is a drawback that not only the braking force of the rear wheel brakes cannot be controlled properly, but also safety in operation of the vehicle cannot be ensured.

The present invention has been made in view of the above-mentioned drawbacks of the prior art, and the present invention is directed to a case where a device or the like that supplies and discharges air pressure to an air spring fails and the air pressure of the air spring becomes abnormally high or low. Another object of the present invention is to provide a brake device that can ensure safety when driving a vehicle by giving an alarm to notify the driver of this and by applying a minimum required braking force to the rear wheel brake.

[Means for solving problems]

In order to solve the above-mentioned problems, the present invention provides an air spring for suspending a vehicle body with respect to an axle and an air pressure applied to the air spring when the vehicle height changes with a change in the weight of the vehicle. Air pressure supply / discharge means for supplying / discharging, rear wheel brakes operated by hydraulic pressure from the master cylinder, and brake fluid pressure provided between the rear wheel brakes and the master cylinder, the brake hydraulic pressure corresponding to the loaded weight of the vehicle. In a brake device comprising a hydraulic control valve for introducing the air pressure of the air spring to output to the rear wheel brake, a detection signal is output when the vehicle height of the vehicle is in an abnormal state for a predetermined time. An abnormality detecting means for outputting, an alarm means for warning this abnormal state based on a detection signal from the abnormality detecting means, and an air pressure introduced into the hydraulic pressure control valve to the atmosphere based on the detection signal from the abnormality detecting means. It adopts a configuration comprising a feature in that a relief valve to release.

[Action]

With the above configuration, the air pressure supply / discharge means for supplying / exhausting air pressure to / from the air spring of the vehicle malfunctions, and the air pressure of the air spring becomes abnormally high or low, so that the vehicle height of the vehicle is abnormal for a predetermined time. When a state is reached, a detection signal is output from the abnormality detection means, the driver can be notified of this abnormal state by the alarm means, and the air pressure introduced into the hydraulic control valve can be released to the atmosphere by the release valve. The brake fluid pressure output from the fluid pressure control valve to the rear wheel brakes can be set to the minimum necessary fluid pressure.

Further, even when the vehicle vibrates greatly and the air pressure of the air spring fluctuates when the vehicle is traveling, the abnormality detection means outputs a detection signal unless the abnormal state of the vehicle height continues for a predetermined time. Therefore, even if the vehicle vibrates greatly during traveling of the vehicle, it is possible to prevent the abnormality detecting means from erroneously detecting this as an abnormal state, and it is possible to eliminate the malfunction of the alarm means.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

First, a vehicle height adjusting device using an air suspension will be described in detail with reference to FIG.

In the figure, reference numeral 1 is an air compressor operated by a motor 2. The compressed air from the compressor 1 is dried by an air dryer 3 and then stored in a tank 5 via an air conduit 4. ing. Reference numeral 6 denotes an air supply valve provided in the tank 5, and the air supply valve 6 stores the compressed air in the tank 5 or supplies air pressure in the tank 5 to air springs 8B and 9B described later. The valve is opened only when it is supplied, and is closed at other times.
Reference numeral 7 is a pressure switch provided in the tank 5, and when the pressure in the tank 5 becomes equal to or lower than a predetermined pressure, the pressure switch 7 causes the control device 13 described later to move the air compressor 1 into the tank 5 via the motor 2. It is operated until it reaches a predetermined high pressure, and the compressed air is again stored in the tank 5 via the air supply valve 6.

8 and 8 suspend the vehicle body on the axle, so
The air suspensions 9 and 9 provided on the right front wheel side are the same as the air suspensions 8 provided on the left and right rear wheel sides, respectively, and the air suspensions 8 and 9 are hydraulic shock absorbers. 8A, 9A and air springs 8B, 9B provided on the upper portions of the hydraulic shock absorbers 8A, 9A, respectively. The air springs 8B, 9B are supplied from the tank 5 into the air springs 8B, 9B. It is suspended so that the vehicle body is maintained at the required set height by the air pressure. Further, vehicle height detectors 8C and 9C are provided in the air springs 8B and 9B, respectively, and the vehicle height detectors 8C and 9C change the loaded weight of the vehicle, that is, the number of passengers and the amount of luggage. The detection signal L is output to the control device 13 when the vehicle height becomes lower than the required set height, and the detection signal H is output when the vehicle height becomes higher.

Reference numerals 10, 10 ... Are air supply / exhaust valves for supplying / exhausting air pressure from the tank 5 into the air springs 8B, 9B via the air conduit 4, and the respective air supply / exhaust valves 10 have a vehicle height higher than a required set height. When the vehicle height is low or high, the valve S is opened by a signal S described later, and when the vehicle height is low, the air springs 8B, 9B
The air pressure from the tank 5 is supplied to the inside of each air spring 8
The vehicle height is raised to the set height by expanding B and 9B. On the other hand, when the vehicle height is higher than the required set height, the air pressure in each of the air springs 8B and 9B is exhausted in the direction of arrow A from the exhaust valve 11 described later via the air conduit 4, and the air springs 8B and 9B are exhausted. The vehicle height is reduced to the set height by reducing the. The supply / exhaust valves 10 are closed when the vehicle height reaches a required set height, and the supply / discharge of air pressure to / from the air springs 8B and 9B is stopped.

Reference numeral 11 denotes an exhaust valve attached to the air dryer 3, and the exhaust valve 11 is opened by a signal T described later when the vehicle height is higher than a required set height, so that the air pressure in each of the air springs 8B and 9B is reduced. Each supply / exhaust valve 10, air conduit 4, air dryer 3
The air is exhausted in the direction of arrow A through the. 1
Reference numerals 2 and 12 denote auxiliary conduits provided between the rear wheel side air springs 9B and the corresponding air supply / exhaust valves 10, and the respective auxiliary conduits 12 are air springs as shown in FIG. The air pressure in 9B is introduced to the pressure adjusting portion side of the hydraulic control valve 19 described later,
The hydraulic pressure control valve 19 controls the brake hydraulic pressure to a value according to the vehicle weight.

Reference numeral 13 controls the operation of the motor 2, the air supply valve 6, each air supply / exhaust valve 10, the exhaust valve 11, etc., and constitutes an air pressure supply / discharge means together with the air compressor 1, the tank 5, the air supply valve 6, the exhaust valve 11, etc. Of the air springs 8B and 9B.
When the detection signal L is output from the vehicle height detectors 8C and 9C in B, the valve opening signal Q is output to the air supply valve 6 of the tank 5 based on the detection signal L and the air supply / exhaust valve 10 is opened. Valve signal S
Is output to open the air supply valve 6 and the air supply / exhaust valves 10 to supply the air pressure in the tank 5 to the air springs 8B and 9B through the air conduit 4 to set the vehicle height to a required level. Raise to height. In addition, the vehicle height detectors 8C and 9
When the detection signal H is output from C, the valve opening signal T is output to the exhaust valve 11 based on the detection signal H, and the valve opening signal S is output to each supply / exhaust valve 10 to open them. By exhausting the air pressure in each of the air springs 8B and 9B from the exhaust valve 11 in the direction of the arrow A through the air conduit 4, the vehicle height is reduced to a required set height.

Then, the vehicle height becomes the required set height, and each vehicle height detector 8
When the output of the detection signal H or L from C or 9C is stopped, the output of each valve opening signal S, T or Q is stopped based on this, and the supply / exhaust valve 10, the exhaust valve 11 or the intake valve 6 is stopped. Close the valve. The detection signals H or L from the vehicle height detectors 8C and 9C are individually output for the air springs 8B and 9B, respectively, and the air springs 8B and 9B individually determine the vehicle height. Can be adjusted. When the vehicle height is adjusted to the required set height by the air springs 8B and 9B, the air supply / exhaust valve 10, the exhaust valve 11 and the air supply valve 6 are closed. On the other hand, when the pressure in the tank 5 becomes equal to or lower than the predetermined pressure, the pressure switch 7 outputs the pressure signal P, and the control device 13 sends the drive signal K to the motor 2 based on the pressure signal P.
Is output, the motor 2 is driven until the inside of the tank 5 reaches a predetermined high pressure, compressed air is generated by the air compressor 1, and an opening signal Q is output to the air supply valve 6 to output the air supply valve. 6 is opened, and compressed air from the air compressor 1 is stored in the tank 5 through the air conduit 4.

Next, the brake device will be described in detail with reference to FIG. In FIG. 2, only one system of the brake piping of the vehicle is shown as an example.

In the drawing, 14 is a master cylinder, and the master cylinder 14
Is operated by a brake pedal 15 provided in a driver's cab (not shown) of the vehicle, and when the brake pedal 15 is depressed, hydraulic pressure is supplied to disc brakes 16 and 17 described later. Reference numeral 16 is a disc brake as a left front wheel brake, 17 is a disc brake as a right rear wheel brake.
Reference numeral 17 is connected to the master cylinder 14 via a brake pipe 18 and is operated by hydraulic pressure from the master cylinder 14. The disc brakes 16, 1 are also used for the right front wheel and the left rear wheel.
7, and is connected to the master cylinder 14 via a brake pipe (not shown).

Reference numeral 19 denotes a hydraulic pressure control valve provided between the master cylinder 14 and the disc brake 17 and provided in the middle of the brake pipe 18. The hydraulic pressure control valve 19 has a pressure adjusting section having a setting spring (both are shown in FIG. (Not shown) is built in so that the hydraulic pressure from the master cylinder 14 is controlled to a value according to the spring load of the set spring, and this controlled hydraulic pressure is output to the disc brake 17 as brake hydraulic pressure. It has become. Then, the air pressure in the air spring 9B located on the right rear wheel side is introduced to the pressure adjusting portion side of the hydraulic pressure control valve 19 via the auxiliary conduit 12, and the set spring is set to a value corresponding to this air pressure. The spring load of is adjusted. Thus, the hydraulic pressure control valve 19 functions as a load sensing valve, and the air pressure in the air spring 9B has a value corresponding to the loaded weight of the vehicle. The braking force is controlled so that an appropriate braking force is applied to the right rear wheel according to the loaded weight of the vehicle. The same applies to the left rear wheel.

Reference numeral 20 denotes an opening valve provided between the pressure adjusting portion side of the hydraulic pressure control valve 19 and the air spring 9B and provided in the middle of the auxiliary conduit 12. The opening valve 20 has abnormal air pressure in the air spring 9B. When it becomes abnormally high or low, it is operated via a switch 22 to be described later, and the pressure adjusting portion side of the hydraulic control valve 19 is operated via an auxiliary conduit 12 from the air spring 9B. The air pressure introduced to the air is released to the atmosphere, and the communication of the air spring 9B with the hydraulic pressure control valve side is shut off. As a result, the set spring of the hydraulic pressure control valve 19 is placed in the bleed state, and the hydraulic pressure control valve 19 moves to the disc brake 1
It is possible to output the minimum necessary brake fluid pressure to 7.

Next, with reference to FIG. 3 and FIG. 4, a device for operating the open valve 20 and the like and its circuit will be described.

In the figure, reference numeral 21 is a vehicle height detector as an abnormality detecting means, which is located separately from the vehicle height detector 9C in each of the air springs 9B and is arranged between the rear wheel axle side and the vehicle body side. The vehicle height detector 21 includes the air compressor 1, the motor 2, the air supply valve 6, the supply / exhaust valves 10, the exhaust valve 11, and the vehicle height detectors 8C and 9C.
Etc. do not operate normally, and when the air pressure in each air spring 9C becomes abnormal pressure due to a failure of the air compressor, a wire disconnection accident, etc., that is, the vehicle height is maintained for a predetermined time. When an abnormal state in which the height deviates from the set height continues, a switching signal R as a detection signal is output to the switch 22 described later.

Reference numeral 22 is a switch which is automatically switched from the contact 22A to the contact 22B by a switching signal R from the vehicle height detector 21, 23 and 24 are display lamps as alarm means, and the lamps 23 and 24 are It is installed in the driver's cab of the vehicle,
The driver can always see it. Here, the indicator lamp 23 is a green light, and when the pneumatic equipment or the like operates normally and the vehicle height is maintained at a required set height, the green light is turned on by closing the contact 22A of the switch 22. It is designed to continue. On the other hand, the indicator lamp 24 is a red lamp and is connected in parallel with the opening valve 20. When the vehicle height deviates from the set height due to a failure of pneumatic equipment or the like and the vehicle height detector 21 outputs the switching signal R, the contact 22B of the switch 22 is closed to turn on the red light. The light is turned on to alert the driver that the vehicle height deviates from the set height, that is, the air pressure of each air spring 9B becomes an abnormal pressure and the system performance is impaired. Then, the release valve 20 releases the air pressure introduced from each air spring 9B to the pressure adjusting portion side of each hydraulic pressure control valve 19 to the atmosphere at this time, and sets the set spring of the hydraulic pressure control valve 19 in the preset state. It is like this.

Next, the operation of the present embodiment configured as described above will be described.

First, when the vehicle height adjusting device such as a pneumatic device is operating normally, the air pressure in each of the air springs 8B and 9B becomes a value corresponding to the loaded weight of the vehicle, and the vehicle height is maintained at the required set height. Therefore, the air pressure in each air spring 9B is introduced to the pressure adjusting portion side of each hydraulic pressure control valve 19 via each auxiliary conduit 12 and each opening valve 20, and the setting spring of each hydraulic pressure control valve 19 is The spring load is set according to the loaded weight of the vehicle. And
The hydraulic pressure from the master cylinder 14 is controlled to an appropriate brake hydraulic pressure by each hydraulic pressure control valve 19 and output to each disc brake 17.

On the other hand, when the pneumatic equipment or the like fails and the vehicle height adjusting device malfunctions, the air pressure in each of the air springs 8B and 9B becomes an abnormal pressure, and the vehicle height deviates from the required set height for a predetermined time. Therefore, the vehicle height detector 21 outputs the switching signal R to the switch 22 and the switch 22
Closes the contact 22B to turn on the red lamp on the display lamp 24 to warn the driver of this and also to release the open valve 20.
Can be operated to release the abnormal pressure of the air pressure introduced from the inside of each air spring 9B to the pressure regulating portion side of each hydraulic pressure control valve 19 to the atmosphere. The output brake fluid pressure can be set to the minimum required value.

Therefore, according to the present embodiment, when a pneumatic device or the like malfunctions, the driver can be warned to inform that the vehicle should be driven carefully, and each disk on the rear wheel side can be operated during braking. It is possible to recognize that the brake acts with the minimum required braking force, so that the vehicle can be safely started or stopped. And even when the air pressure in each air spring 9B is abnormally high,
It is possible to prevent the air pressure from being introduced into the pressure adjusting portion of each hydraulic pressure control valve 19 by each opening valve 20, and it is possible to avoid the risk of locking the rear wheel side due to so-called excessive braking.
It is possible to ensure safety when driving the vehicle.

In addition, even when the vehicle vibrates greatly during traveling of the vehicle and the air pressures of the air springs 8B and 9B fluctuate, the vehicle height is abnormal (the vehicle height deviates from the required set height and becomes too high). , The vehicle height detector 21 serving as an abnormality detecting means unless the condition (too low) continues for a predetermined time.
Since the switching signal R is not output from the vehicle, even if the vehicle vibrates greatly when the vehicle is traveling, the vehicle height detector 21 erroneously detects this as an abnormal state and switches 22 to the contact 22A.
It is possible to prevent switching from the contact 22B to the contact 22B, and it is possible to eliminate the problem that the display lamp 24 as an alarm means is erroneously turned on.

Although the opening valve 20 is provided in the middle of the auxiliary conduit 12 in the above embodiment, the opening valve 20 may be attached to the hydraulic pressure control valve 19. In addition, the auxiliary conduit 1
2 may also be directly connected in the air spring 9B.

Further, a buzzer or the like may be used as the alarm means instead of the display lamp 24 that lights the red light. In this case, the display lamp 23 can be omitted.

〔The invention's effect〕

As described above in detail, according to the present invention, when the vehicle height of the vehicle is in an abnormal state for a predetermined time, a detection signal is output from the abnormality detection means, and the abnormal state is warned by the warning means. Since the air pressure introduced into the hydraulic pressure control valve is opened to the atmosphere by the release valve, when the air pressure supply / discharge means for supplying / discharging air pressure to / from the air spring of the vehicle operates normally, the appropriate braking force for the rear wheel brakes is used. In addition, if the air pressure supply / discharge means fails and the air pressure of the air spring becomes abnormally high or low, and the vehicle height becomes abnormal for a predetermined time, It is possible to notify the driver of an abnormal condition by an alarm means to encourage them to drive carefully, and to apply the minimum necessary braking force to the rear wheel brakes, which can surely improve the safety during driving. .

Even when the vehicle vibrates greatly and the air pressure of the air spring fluctuates when the vehicle is running, the abnormality detection means erroneously determines this as an abnormal state unless the abnormal vehicle height continues for a predetermined time. It is possible to prevent the detection, and it is possible to eliminate the problem that the alarm means malfunctions.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a vehicle height adjusting device, FIG. 2 is a circuit diagram of a brake device showing one system of brake piping, and FIG. 3 is an explanatory diagram of a vehicle height detector and a display lamp provided in a vehicle. Four
The figure is a circuit diagram for explaining the operation of the indicator lamp and the open valve. 8, 9 ... Air suspension, 8B, 9B ... Air spring, 10 ... Supply / exhaust valve, 12 ... Auxiliary conduit, 14 ... Master cylinder, 16, 17 ... Disc brake, 19
...... Hydraulic pressure control valve, 20 ...... Open valve, 21 ...... Vehicle height detector, 22 ...... Switch, 23,24 ...... Indicator lamp.

Claims (1)

[Claims] 1. An air spring for suspending a vehicle body with respect to an axle, and an air pressure supply / discharge means for supplying / discharging air pressure to / from the air spring when the vehicle height changes in accordance with a change in the weight of the vehicle. A rear wheel brake operated by hydraulic pressure from a master cylinder, and a brake hydraulic pressure provided between the rear wheel brake and the master cylinder for outputting a brake hydraulic pressure corresponding to the loaded weight of the vehicle to the rear wheel brake. A brake device including a hydraulic control valve for introducing the air pressure of the air spring, and an abnormality detecting unit that outputs a detection signal when the vehicle height of the vehicle is in an abnormal state for a predetermined time; An alarm means is provided for alarming this abnormal state based on a detection signal from the abnormality detection means, and an opening valve for opening the air pressure introduced into the hydraulic pressure control valve to the atmosphere based on the detection signal from the abnormality detection means. thing Brake device according to claim.