JPH0347957Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an air brake system for an automobile that uses an air spring as a suspension spring, and in particular a load sensing valve between a brake valve connected to a brake pedal and a brake chamber that operates the brake. The present invention relates to an air brake device which is connected to an axle and controls braking force according to the load applied to an axle.

Large vehicles such as trucks and buses are generally equipped with an air brake device, which uses a compressor to compress air and store it in an air tank, and uses this compressed air to operate the brakes. . In other words, when the brake pedal is depressed, the brake valve opens, control pressure is supplied to the relay valve, the relay valve is opened, compressed air in the air tank is supplied to the brake chamber, and the brakes are activated. There is.

Generally speaking, in large vehicles such as trucks and buses, the value of the load applied to the axle changes greatly between when the vehicle is empty and when it is loaded. Therefore, when such a change in load is large, it is preferable to change the braking force accordingly. Therefore, in general, in such vehicles, a load sensing valve is connected between the brake valve and the relay valve, and the lever of this valve is connected to the axle, thereby supplying the load to the relay valve according to the amount of deflection of the suspension spring. The air pressure can be controlled. Since the amount of deflection of the suspension spring is approximately proportional to the load applied to the axle, it becomes possible to control the braking force according to the load using the load sensing valve.

However, when an air spring is used as a suspension spring, the air spring is connected to the air tank through a leveling valve, so the amount of deflection of the air spring is controlled by the action of the leveling valve regardless of the load. It is adjusted so that it is always constant, and the vehicle height is adjusted accordingly. Therefore, in a vehicle equipped with such an air spring, the displacement of this spring cannot be transmitted to the load sensing valve as a change in load, and therefore the air brake device of such a vehicle also transmits its braking force. It was not possible to control it according to the load.

The present invention has been made in view of these problems, and provides an air brake device that controls braking force in accordance with the load applied to an axle suspended by an air spring. The purpose is to

The present invention will be explained below with reference to an illustrated embodiment.
FIG. 1 shows an air brake device according to this embodiment, and this air brake device is equipped with an air tank 1. As shown in FIG. The air tank 1 is connected to a compressor (not shown), and stores air compressed by the compressor.
The air tank 1 is connected to a brake valve 2. A rod 3 for adjusting the opening degree of the brake valve 2 is pressed by a brake pedal 4. The brake valve 2 is connected to a relay valve 5, and when control pressure is applied from the brake valve 2, the valve 5 opens, and compressed air is supplied from the air tank 1 to the brake chamber 6.

A load sensing valve 7 is connected to a conduit connecting the brake valve 2 and the relay valve 5. The valve 7 is controlled by the internal pressure of the air spring 8, and the internal pressure of the air spring 8 is supplied to the load sensing valve 7 as control pressure.

Next, the structure of the load sensing valve 7 will be explained with reference to FIG. 2. The valve 7 includes a casing 9, and the casing 9 has an inlet port 10 and an outlet port 11 formed therein. These ports 10 and 11 are connected to a brake valve 2 and a relay valve 5, respectively. Furthermore, a piston 12 is disposed within the casing 9 so as to be slidable in the vertical direction. A disc valve 13 is housed in a recess formed inside the piston 12, and this valve 13 is fitted with an opening 14 formed in the upper part of the piston 12.
It is designed to open and close.

Piston 12 of the load sensing valve 7
An immersion valve 15 is further housed inside, and this valve 15 is connected to the disc valve 13.
It is located below. The immersion valve 15 is located above the immersion valve seat 16, and a spring 20 is interposed between the pair of valves 13 and 15. Further, another piston 17 is disposed below the piston 12, and a plunger 1 is disposed below this piston 17.
8 is stored. The plunger 18 is adapted to push the piston 17 via a plunger seat 19.

A control lever 21 is provided below the load sensing valve 7. The lever 21 is connected to a bracket 22 connected to the casing 9 of the valve 7.
is rotatably supported via a pin 23.
The control lever 21 is connected to the air chamber 24. The air chamber 24 constitutes an actuator, and has a diaphragm 25 arranged inside a container consisting of a closed space. A rod 26 whose length is adjustable is fixed to the diaphragm 25, and the tip end of the rod 26 is connected to the control lever 21 via a pin 27. The air chamber 24 is rotatably supported by a bracket 28 attached to the casing 9 of the valve 7 via a pin 29. And the port 31 of the air spring 8 and this air chamber 24
is connected to the port 32 by a conduit,
The internal pressure of the air chamber 8 is applied to the upper surface of the diaphragm 25.

In the above configuration, when the brake pedal 4 provided at the driver's seat is depressed, the rod 3 of the brake valve 2 is pushed by the pedal 4, so that the valve 2 opens. Therefore, the compressed air in the air tank 1 passes through the valve 2 and the load sensing valve 7 to the relay valve 5.
is applied as a control pressure to open the relay valve 5. Therefore, compressed air is stored in air tank 1.
from the brake chamber 6 through the relay valve 5.
will be added to. The pressure applied to the brake chamber 6 is received by its diaphragm, and the rod 30 connected to the diaphragm is pushed out, pressing the brake shoe against the drum via the brake cam.
Control operations are thereby performed.

The control pressure applied to the relay valve 5 to perform this control operation is controlled by a load sensing valve 7 in accordance with the load applied to the axle. To explain this operation, the pressure within the air spring 8 shown in FIG. 2 is approximately proportional to the load applied to the axle to which this spring 8 is connected. The pressure within the air spring 8 is then applied to the port 32 of the air chamber 24 via the port 31 and the conduit. Therefore, the diaphragm 25 of the air chamber 24 is pressed with a pressure corresponding to the internal pressure of the air spring 8.
This pressure causes the rod 26 to be pushed out. Therefore, the control lever 21 rotates clockwise in FIG. 2 about the pin 23, and the lever 21
1 pushes the plunger 18 of the load sensing valve 7. That is, the plunger 18 is pushed with a force approximately proportional to the load applied to the axle.

On the other hand, when the brake pedal 4 is depressed, the port 1 of the load sensing valve 7 is transferred from the brake valve 2 to the port 1 of the load sensing valve 7.
Compressed air is supplied to the piston 12, and the pressure of this air exerts a force that pushes the piston 12 downward. When this force overcomes the force pushing the piston 12 upward, the piston 12 moves downward and the disc valve 13
is closed and the decompression operation begins. The pressure reduction start point of the load sensing valve 7 is the air chamber 2.
It changes depending on the pressure applied to 4, that is, the magnitude of the load on the axle. When the pedal 4 is then depressed, the air pressure from the brake valve 2 increases, the piston 12 is pushed up, the disc valve 13 is once opened, and the passage to the relay valve 5 is opened. This increases the air pressure above the piston 12, pushing the piston 12 down again to bring it into equilibrium. Then, due to the difference in area between the upper and lower sides of the piston 12, the air pressure is reduced at a constant ratio and air is sent to the relay valve 5. In this way, the load sensing valve 7 supplies compressed air at a pressure corresponding to the load applied to the axle to the relay valve 5 as a control pressure, thereby adjusting the braking force according to the load.

As described above, according to the air brake device of this embodiment, the pressure air chamber 24 in the air spring 8
is converted into a mechanical displacement of the rod 26, and a force corresponding to this displacement is applied to the plunger 18 of the load sensing valve 7.
Since the position at which the brake starts the pressure reducing operation is controlled in accordance with the load applied to the axle, the braking force can also be controlled in accordance with the load.

The air spring 8 is designed to adjust the vehicle height using a leveling valve, and its deformation amount does not change depending on the load, but by converting the internal pressure into a stroke using the air chamber 24. Even in a vehicle equipped with an air suspension device, the load sensing valve 7 can be provided to adjust the braking force. Furthermore, the force for pushing up the plunger 18 is adjusted by making it possible to select one of the plurality of pin holes 34 provided in the control lever 21 for the pin 27 that connects the rod 26 and the control lever 21. It is possible to obtain a constant braking force regardless of changes in the number of air springs due to changes in vehicle specifications. Further, by making the above selection, the effectiveness of the brake can be adjusted according to the driver's preference. For example, if you increase the number of air springs due to a change in vehicle specifications or if you want to increase the braking force, use the pin hole 34 on the outside of the lever 21, or use the pin hole 34 on the outside of the lever 21 when you decrease the number of air springs or want to make the braking force weaker. Rod 26 in pin hole 34
It is only necessary to pivotally connect it with pin 27. Further, since the length of the rod 26 is adjustable, it can be easily adjusted during installation.

Although the present invention has been described above with reference to an illustrated embodiment,
The present invention is not limited to the above embodiments, and various modifications can be made based on the technical idea of the present invention.

As described above, the present invention provides a load sensing valve between a brake valve connected to a brake pedal and a brake chamber that operates the brake in a vehicle whose axle is suspended from the vehicle body by an air spring. In an air brake device that controls braking force according to the load applied to the axle, the pressure chamber is connected to an air spring and a diaphragm defines the pressure chamber. Attach one end of the rod to the load sensing valve, pivot the main body side of the actuator that moves the rod in and out according to the pressure in the pressure chamber and convert pressure changes into mechanical displacement to the load sensing valve side, and adjust the length of the rod. The present invention relates to an air brake device which is adjustable, and in which the other end of the rod is pivotally connected to a control lever of a load sensing valve, and the pivotal position between the control lever and the other end of the rod can be changed. Therefore, according to the present invention, it is possible to control the braking force of the air brake in accordance with the load applied to the axle even in an air suspension vehicle. In addition, the air brake device can always obtain the appropriate braking force, and can easily adjust the effectiveness of the brake regardless of the number of air springs or according to the driver's preference, and can also be easily adjusted during installation. It becomes possible to provide

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an air brake device according to an embodiment of the present invention, and FIG. 2 is an enlarged longitudinal cross-sectional view of the same main part. In addition, in the symbols used in the drawings, 2... Brake valve, 4... Brake pedal, 5... Relay valve, 6... Brake chamber, 7... Load sensing valve, 8... Air spring, 21
...Control lever, 24...Air chamber, 25...
...It's a diaphragm.

Claims (1)

[Scope of utility model registration request] A load sensing valve is connected between a brake valve connected to a brake pedal and a brake chamber that operates the brake in a vehicle whose axle is suspended on the vehicle body by an air spring,
An air brake device that controls braking force according to the load applied to the axle has a sealed pressure chamber, this pressure chamber is connected to an air spring, and one end of a rod is attached to a diaphragm that defines the pressure chamber. the rod is moved in and out according to the pressure in the pressure chamber, and the main body side of an actuator that converts pressure changes into mechanical displacement is pivotally connected to the load sensing valve side, and the length of the rod is adjustable; An air brake device characterized in that the other end of the rod is pivotally connected to a control lever of a load sensing valve, and the pivotal position between the control lever and the other end of the rod can be changed.