JPH0617652Y2 - Vehicle load-responsive brake pressure distribution type air brake device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a load-responsive brake pressure distribution type air brake device for a vehicle, and more particularly to a device provided with an air suspension device.

<Prior Art> An example of a conventional air brake device of this type is shown in FIG. 4 (see Japanese Patent Publication No. 56-51941).

First, an air type suspension device (a region shown by a broken line in FIG. 4) will be described. A vehicle frame (not shown) and a wheel axle (not shown) are bellows type air springs 1a,
They are connected by 1b. These air springs 1
Pressurized air is supplied from a reserve tank 2 for air suspension to a and 1b. Further, a vehicle height adjusting valve 3 having an orifice is interposed in an air line connecting the air spring 1a and the reserve tank 2.

The vehicle height adjusting valve 3 adjusts the air pressure supplied to the air springs 1a and 1b in accordance with the vehicle height, that is, the load, and keeps the vehicle height substantially constant regardless of the change in the load. There is.

Next, the air brake device will be described. The air pressure supplied to the air springs 1a and 1b is supplied to the port a of the first double check valve 4, and the switching valve 5 is connected to the port b of the first double check valve 4. The larger one of the pressures supplied from the c port is supplied to the a port of the proportioning relay valve 6 from the c port.

Air pressure is supplied from the reserve tank 2 to the b port of the switching valve 5, and air pressure is supplied to the c port of the switching valve 5 from an air brake reserve tank (not shown).

Then, the switching valve 5 communicates an atmosphere port (not shown) with the port a when the air springs 1a and 1b are normal based on the air pressure in the reserve tank 2, and introduces the atmosphere into the port b of the first double check valve 4. . Therefore, the air spring 1 is connected to the port a of the proportioning relay valve 6 via the first double check valve 4.
Air pressure from a and 1b is supplied.

On the other hand, when the failure of the air springs 1a, 1b is detected by the air pressure of the reserve tank 2, that is, when the air pressure of the reserve tank 2 becomes a predetermined value or less, the switching valve 5 connects the a port and the c port to each other. 1 Supply the air pressure from the reserve tank for the air brake to the b port of the double check valve 4. Therefore, the air spring 1a,
When the air pressure drops due to the failure of 1b, the air pressure from the air brake reserve tank is supplied to the port a of the proportioning relay valve 6 via the first double check valve 4.

The b port of the proportioning relay valve 6 is supplied with air pressure from the reserve tank for the air brake, and the c port of the proportioning relay valve 6 is connected to a foot brake (not shown). Air pressure is supplied from (not shown).
The d port of the proportioning relay valve 6 is connected to the spring chambers 7a and 7b for braking the rear wheels.

The port a of the second double check valve 8 is communicated with a cab control valve (not shown), and the port b of the second double check valve 8 is communicated with the port e of the proportioning relay valve 6. The c port of the second double check valve 8 is connected to the emergency spring brake working chamber of the spring chambers 7a and 7b through a quick release valve 9.

When the spring brake is not operated, the air supplied from the cab control valve is introduced into the spring brake operating chambers of the spring chambers 7a and 7b through the second double check valve 8 and the quick release valve 9 so that the brake by the spring is not operated. Becomes
Further, when the spring brake is operated, the air in the spring brake operating chamber is discharged into the atmosphere from the quick release valve 9 and the brake by the spring is operated.

Further, when the air springs 1a and 1b are normal, the vehicle pressure adjusting valve 3 supplies air pressure to the air springs 1a and 1b which is substantially proportional to the load. At this time, since the air pressure in the reserve tank 2 is also a normal value, the port a of the switching valve 5 is opened to the atmosphere, and thus the port a of the proportioning relay valve 6 is connected to the port a via the first double check valve 4. Air pressure is supplied to the air springs 1a and 1b, which is approximately proportional to the load.

When the foot brake is operated in this state, air is supplied from the brake valve to the c port of the proportioning relay valve 6. As a result, from the d port of the proportioning relay valve 6 to the spring chamber 7
Air pressure that is approximately proportional to the load is introduced to a and 7b,
Air brake is activated. Therefore, a braking force (brake pressure) that is substantially proportional to the load is obtained.

On the other hand, when the air springs 1a and 1b fail, the air pressure at the port a of the first double check valve 4 drops and the air pressure in the reserve tank 2 drops. As a result, from the port a of the switching valve 5 to the first double check valve 4
A substantially constant air pressure is supplied to the b port from the air brake reserve tank, and the air pressure is supplied to the a port of the proportioning relay valve 6.

Therefore, even when the air springs 1a and 1b fail, a substantially constant air pressure is supplied to the port a of the proportioning relay valve 6, and therefore when air is supplied from the brake valve, the port a of the proportioning relay valve 6 is supplied. A predetermined air pressure is supplied to the spring chambers 7a and 7b. As a result, a substantially constant braking force can be secured and fail-safe can be achieved when the air springs 1a and 1b fail.

<Problems to be Solved by the Invention> However, in such a conventional air brake device, the air pressure supplied to the air springs 1a and 1b ensures a braking force substantially proportional to the load, while the air spring 1a is secured. , 1b is detected by the air pressure in the reserve tank 2, there are the following drawbacks.

Since the vehicle height adjusting valve 3 having an orifice is provided in the air line connecting the air springs 1a and 1b and the reserve tank 2, even if the air pressure is lowered due to the failure of the air springs 1a and 1b, It takes time for the air pressure in the reserve tank 2 to drop corresponding to the drop in the air pressure of the air springs 1a and 1b. Therefore, the switching valve 5 does not operate instantaneously in response to the failure of the air springs 1a and 1b.

The present invention has been made in view of such a situation, and the air pressure supplied to the air spring ensures a braking force corresponding to the loaded load while instantaneously providing a predetermined braking force even when the air spring fails. An object is to provide an air brake device that can be secured.

<Means for Solving Problems> Therefore, according to the present invention, the first port is connected to the discharge port of the vehicle height adjusting valve, and the discharge air of the vehicle height adjusting valve is normally passed through the first air circuit. Is supplied to the air spring while the air pressure of the third port is higher than the air pressure of the second port, a switching valve that supplies the discharge air to the third port and a third port of the switching valve. The second air circuit to which one end is connected, the air pressure supplied to the air spring is input to the first port, the air pressure of the second air circuit is input to the second port, and the one with the higher pressure is selected. A double check valve that outputs from a third port; and a third air circuit in which a check valve that connects the first air circuit and the second air circuit in communication and allows only an air flow to the second air circuit is interposed. , The double A proportioning relay valve that inputs the output pressure of the third port of the check valve and outputs a control pressure for braking according to the pressure when the brake is activated, and a braking pressure that corresponds to the control pressure input from the valve And a brake actuator.

<Operation> In this way, when the air spring is normal, the discharge air of the vehicle height adjusting valve is supplied to the air spring through the first air circuit, and the second air circuit is supplied through the check valve of the third air circuit. The pressure of the discharged air is accumulated from the first air circuit. Then, the proportioning relay valve supplies the supply pressure to the air spring corresponding to the loaded load through the double check valve to generate the braking force corresponding to the loaded load. Further, when the air spring fails, the air accumulated in the second air circuit and the air discharged from the vehicle height adjusting valve are supplied to the proportioning relay valve via the second air circuit to generate the braking force.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. The same elements as those of the conventional example will be described with the same reference numerals as in FIG. Further, in the present embodiment, only the main part will be described, and the other main parts are the same as in the conventional example, and therefore the description will be omitted.

In the figure, a first port (a in FIG. 1) of a third double check valve 10 as a switching valve is connected to the discharge port of the vehicle height adjusting valve 3 having an orifice so as to communicate with the third port.
The second port (b in FIG. 1) of the double check valve 10 is connected to one end of a first air circuit A, which is an air supply pipe. The other end of the first air circuit A has an air spring 1
The other end of the first air circuit A is connected to the a port as the first port of the first double check valve 4 similar to the conventional example.

Here, the third double check valve 10 is arranged so that the second port (a in FIG. 1) side is the upper side (top side), and normally the valve body 10a is as shown in FIG. The third port (c in FIG. 1) is closed.

The vehicle height adjusting valve 3 is composed of a three-way valve, and the discharge pressure of the reserve tank 2 can be changed by repeatedly discharging the air to the atmosphere and supplying the third double check valve 10. ing.

Further, one end of a second air circuit B formed of an air supply pipe is connected to the third port of the third double check valve 10 and the other end of the second air circuit B is connected to the second port of the first double check valve 4. It is connected to the b port as a port.

In addition, an intermediate portion between the first air circuit A and the second air circuit B is communicatively connected by a third air circuit C including an air supply pipe,
The third air circuit C includes the first air circuit A to the second air circuit B.
A check valve 11 is provided which allows only air flow to.

The c port as the third port of the first double check valve 4 is communicatively connected to the a port of the proportioning relay valve 6 shown in FIG.

Next, the operation will be described.

When the air springs 1a and 1b are normal, the valve body 10a of the third double check valve 10 closes the third port, so the air discharged from the vehicle height adjusting valve 3 flows into the first air circuit A from the second port. And then supplied to the air springs 1a and 1b. Therefore, in order to keep the vehicle height constant by the vehicle height adjusting valve 3, the air pressure substantially proportional to the load is supplied to the air springs 1a and 1b.

Further, the air supplied to the first air circuit A is supplied to the second air circuit B via the check valve 11 of the third air circuit C and accumulated in the second air circuit B. Here, due to the pressure loss in the check valve 11, the pressure of the air flowing through the first air circuit A is higher than the pressure of the air stored in the second air circuit B.

Therefore, when the air springs 1a and 1b are normal, the air pressure that is substantially proportional to the loading load supplied from the first air circuit A to the air springs 1a and 1b is transmitted via the first double check valve 4 to the proportioning valve a of the proportioning relay valve.
It is supplied to the port (see FIG. 4). Therefore, when air pressure is supplied to the proportioning relay valve from the brake valve during brake operation, that is, from the proportioning relay valve, air pressure that is approximately proportional to the load is supplied to the air chamber as a brake actuator. Therefore, it is possible to secure a braking force that is substantially proportional to the loaded load.

On the other hand, if the air springs 1a and 1b fail, the air pressure in the first air circuit A drops, so the air pressure at the port a of the first double check valve 4 drops. As a result, the passage of the first double check valve 4 is switched by the air pressure stored in the second air circuit B, and the second air circuit B communicates with the a port of the proportioning relay valve. In the third double check valve 10, the valve body 10a is pushed upward by the air pressure stored in the second air circuit B, the second port is closed and the third port is opened.

Therefore, when the air springs 1a, 1b fail, the discharge air of the vehicle height adjusting valve 3 is transferred to the a port of the proportioning relay valve via the third double check valve 10, the second air circuit B and the first double check valve 4. Is supplied with good responsiveness. Therefore, the air spring 1
Even if a and 1b fail, the high pressure discharge air of the vehicle height adjusting valve 3 is supplied to the a port of the proportioning valve. Therefore, when the brake is actuated, a predetermined air pressure is supplied from the proportioning relay valve to the air chamber. Can be supplied to. As a result, even if the air springs 1a and 1b fail, a predetermined braking force can be secured and the fail-safe function can be maintained.

FIG. 3 shows a modification of the third double check valve,
A spring 12c for urging the valve body 12a toward the third port is attached to the third double check valve 12,
In this case, even if the second port and the third port are arranged at the horizontal position, the same function as the above operation is obtained.

<Effect of the Invention> As described above, the present invention changes the passage of the double check valve by the pressure accumulated in the second air circuit to change the discharge air of the vehicle height adjusting valve when the air spring fails. Since the proportioning valve is supplied through the second air circuit and the double check valve, a predetermined braking force can be secured and the fail-safe function can be maintained even when the air spring fails.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an essential part showing an embodiment of the present invention, FIG. 2 is a sectional view of an essential part of the same, FIG. 3 is a view showing a modification of the second double check valve, and FIG. 4 is a braking device. FIG. 6 is a circuit diagram showing a conventional example of 1a, 1b ... Air spring, 2 ... Reserve tank, 3 ... Vehicle height adjusting valve, 4 ... First double check valve, 10 ... Third double check valve, 11 ... Check valve, A ... … First air circuit, B… Second air circuit, C…
… Third air circuit

Claims (1)

[Scope of utility model registration request] 1. A vehicle including a vehicle height adjusting valve which is interposed between an air reserve tank and an air spring to control the air pressure supplied to the air spring so as to keep the vehicle height substantially constant, The first port is connected to the discharge port of the vehicle height adjusting valve, and normally, the discharge air of the vehicle height adjusting valve is supplied to the air spring through the first air circuit, while the air pressure of the third port is A switching valve that supplies the discharge air to the third port when the pressure becomes higher than the air pressure of the second port, and a third switching valve of the switching valve.
A second air circuit, one end of which is connected to the port, and the air pressure supplied to the air spring is input to the first port and the air pressure of the second air circuit is input to the second port to increase the pressures. A third check air, in which a double check valve for outputting one from a third port and a check valve for connecting only the first air circuit and the second air circuit to each other and allowing only an air flow to the second air circuit are interposed. A circuit, a proportioning relay valve that inputs the output pressure of the third port of the double check valve and outputs a control pressure for braking according to the pressure when the brake is operated, and a proportioning relay valve that responds to the control pressure input from the valve. A load actuating brake pressure distribution type air brake device for a vehicle, comprising: a brake actuating device for generating a brake pressure.