JPS6048376B2 - Safety device in dual air brake system for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a safety device that allows the air brakes of other systems to continue to operate normally even if one system of air brakes fails in a two-system air brake system for a vehicle. It is.

In air brake systems for vehicles, pressurized air generated by a single compressor is stored in two independent air reservoirs, and these two air reservoirs are used as pressure sources to operate two systems of air brakes. It is done a lot. Normally, the two air reservoirs are each large enough to store enough pressurized air to perform several braking operations. Even if one air brake fails (the brake does not operate because the pressure does not rise sufficiently), the other brake can be activated several times, so it is possible to stop the vehicle, and the vehicle This can improve safety.
However, in conventional dual-system air brake systems, if one system fails, all the compressed air supplied from the compressor will leak from the damaged part on the failed side. The air reservoir is also not replenished with pressurized air, and after the pressurized air stored in the normal air reservoir is consumed and exhausted, both brake systems will not operate.

Therefore, in the past, a pressure gauge was installed in the air brake circuit, and when the pressure dropped below a predetermined value, the driver was notified by an instruction from the pressure gauge or by an alarm, and the vehicle was stopped based on this. The procedure was to either repair the damaged part or close the cock installed in the pressure air passage to the air reservoir on the failed side. However, if the driver neglects to monitor the pressure gauge or ignores the warning for some reason, such measures will not be taken and the vehicle will continue to drive without brakes, resulting in serious damage. There was a risk of causing an accident. The present invention was made in order to eliminate the J drawbacks of such conventional brake systems, and its first purpose is to solve the problem when one of the air brakes in a two-system air brake system fails. Another object of the present invention is to provide a safety device that can automatically disconnect the air brake on the side that has failed from the compressor and prevent the pressurized air supplied from the compressor from leaking any further from the damaged part. Another object of the present invention is to use a single control valve to enable the other system to continue operating normally even if one of the two systems fails. be. Furthermore, one of the important objects of the present invention is to achieve the above object at low cost without complicating the structure of the brake system as much as possible. In order to achieve the above object, the present invention divides pressurized air generated by a single compressor into two parts and supplies the divided air to first and second air reservoirs through first and second check valves, respectively. Then, two independent systems of air brakes are operated using these first and second air reservoirs as pressure sources. In a two-system air brake system for a vehicle, the first and second check valves are connected to the W-force air passage on the compressor side, and (1) the first and second check valves are connected to the two pressure-receiving surfaces facing each other, respectively. and the pressure of the second air reservoir, due to the difference between these two pressures. differential piston, (2
holding means for normally holding the differential piston in a neutral position by elastic force; (3) when the pressure in the first air reservoir becomes lower than the pressure in the second air reservoir by a certain limit or more; When the piston moves from the neutral position,
(4) the pressure in the second air reservoir becomes lower than the pressure in the first air reservoir by more than a certain limit, and the differential piston A safety device including a second cut-off valve that cuts off the pressure air passage to the second air reservoir is inserted when the air brake moves from the neutral position, and when one air brake system fails, the side that failed By disconnecting the air brake system from the compressor,
This is characterized in that pressurized air is supplied to the air brake on the normal side as usual.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be explained in more detail based on the drawings.

In FIG. 1, 1 is a compressor, and compressed air generated by the compressor 1 is sent to a wet tank 4 via a pipe 2 and a check valve 3.

The high temperature pressurized air supplied from the compressor 1 is cooled in a wet tank 4, and moisture is condensed and removed.
5 is a pressure regulator, and wet tank 4
When the pressure of the compressor 1 rises to a predetermined value, the suction valve of the compressor 1 is opened, and the supply of compressed air by the compressor 1 is stopped.

The pressure air from which moisture has been removed in the wet tank 4 is sent to the first air reservoir 9 via the pipe 6, the safety device 100, the pipe 7, and the check valve 8, while the pressure air is sent to the first air reservoir 9 via the pipe 11, the safety device 1
00, is also sent to the second air reservoir 14 via the conduit 12 and check valve 13.

The pressure in the air reservoirs 9 and 14 is determined by the pipes 15 and 16, respectively.
is guided to the safety device 100 by. The internal structure of the safety device 100 will be explained in detail later. When the brake pedal 17 is depressed, the pressurized air once stored in the first air reservoir 9 is sent to the air booster 22 via the pipe 18, operating valve 19 and pipe 21, where it is converted into hydraulic pressure. , is sent to the front wheel cylinder 24 via the conduit 23, and operates the front brake.

The above will be collectively referred to as the front brake system. Note that 25 is a brake free reservoir. Like the front brake system, the rear brake system also includes a second air reservoir 14, a pipe 26, an operating valve 19, a pipe 27, an air booster 28, and a brake fluid reservoir 2.
9, a conduit 31, a rear wheel sill 32, etc.

The safety device 100 is shown in an enlarged view in FIG.

In the figure, 101 is a main body, a through hole is bored in the main body 101, and openings at both ends of the through hole are respectively plug 1.
Blocked by 02,103. A piston 104 having a large diameter portion 105 at the center is slidably fitted in the middle of the main body 101, and both ends of the piston 104 are fixed to the main body 101 by C-shaped retaining rings 108, 109. It passes through fixed rings 111 and 112, and furthermore, valve elements 113 and 114 are fixedly installed at the tips thereof. Piston 104 is held at a neutral position by the elastic force of coil springs 115 and 116. Piston 104
, seal rings 117, 118, 119 between the fixed rings 111, 112, the plugs 102, 103, and the main body 101.
, 121, 122, 123, 124, etc., and as a result, the first pressure chamber 125, the second pressure chamber 126, the first air chamber 127, and the second air chamber 12 are separated from each other.
There are 8 four rooms formed.

Pressurized air guided by the pipe 6 enters the first air chamber 127 from the boat 131 and is sent out from the boat 132 toward the first air reservoir 9, but this passage is connected to the valve 113 and the plug 102. It can be shut off by a first cut-off valve 133 configured by.

On the other hand, the pressurized air guided by the pipe 11 is transferred to the boat 134.
The air enters the second air chamber 128 from the boat 135 and is sent out from the boat 135 to the second air reservoir 14; Can be blocked. Further, the pressure in the first air reservoir 9 is guided from the boat 137 to the first pressure chamber 125, and the pressure in the second air reservoir 14 is guided from the boat 138 to the second pressure chamber 126.

Therefore, the piston 104 receives the pressure of the first air reservoir 9 and the second air reservoir 14 on the first pressure receiving surface 141 and the second pressure receiving surface 142 formed on both sides of the large diameter portion 105, respectively, and due to the difference between the two pressures. It is a differential piston that operates in parallel. In the brake system configured as described above, the piston 104 is held at the neutral position by the coil springs 115, 116 while the pressures of the wet tank 4 and the air reservoirs 9, 14 are all equal to atmospheric pressure. Cut-off valve 133,1
All 36 are open.

Therefore, if the compressor 1 is driven in this state, air is forced to be sent to the air reservoirs 9 and 14 via the wet tank 4 and the safety device 100, and the pressure in each reservoir increases.
When the pressure in the wet tank 4 reaches a predetermined value, the air regulator 5 detects this and releases the suction valve of the compressor 1, so the compressor 1 becomes idle and the supply of air is stopped. This completes the brake operation criteria, and when the brake pedal 17 is depressed, the operating valve 19 opens and pressurized air is supplied to the air booster 2.
2 and 28, hydraulic pressure is generated, the wheel cylinders 24 and 32 are operated, and braking is performed.

If the pressure in the air reservoirs 9, 14 decreases as a result of brake operation, pressurized air is replenished from the wet tank 4, and as a result, if the pressure in the wet tank 4 decreases, the air regulator 5 returns the suction valve of the compressor 1 to its operating state. , the compressor 1 starts pumping air again, and pressurized air is replenished. In this way, while both the front brake system and the rear brake system are normal, the pressures in the first and second air reservoirs 9, 14 are maintained at substantially constant heights that are equal to each other. However, if the air pipe line of the front system were to be damaged, the pressurized air in the first air reservoir 9 would flow out from this damaged portion, and the pressure in the first air reservoir 9 would drop. In this case, the pressure in the wet tank 4 will naturally decrease, but since the air in the second air reservoir 14 is prevented from flowing backwards by the check valve 13, the pressure in the second air reservoir 14 will not decrease. , a significant difference in pressure occurs between the second air reservoir 9 and the second air reservoir 14. As a result, a significant difference occurs in the pressure between the first and second pressure chambers 125, 126, which are in communication with both reservoirs 9, 14, and the piston 104 is moved to the side of the first pressure chamber 125, where the pressure is lower. Therefore, the valve 1 fixed to the piston 104
13 comes into contact with the end face of the plug 102, and the passage of pressurized air from the boat 131 to the boat 132 is blocked. Therefore, in this state, the compressed air pumped from the compressor 1 is not sent to the first air reservoir 9, but only to the second air reservoir 14, and the second air reservoir 14 is Similarly, pressurized air can be replenished, and the rear brake system can continue to operate normally. The above explained the case where the front brake system failed.
Since the safety device 100 is completely symmetrically constructed, even if the rear brake system fails, the failed rear brake system is automatically disconnected from the compressor 1 in the same way.
The front brake system can continue to operate normally. Furthermore, after repairing the brake system on the failed side, if the pressure air in the air reservoirs 9 and 14 is released and the pressure in both air reservoirs becomes atmospheric pressure, the first and second pressure chambers 125 of the safety device 100 , 126 are both at atmospheric pressure, and the piston 104 is moved by the coil spring 1.
15, 116 to return to the central position, the cut-off valve 133 (or 1
36) is opened and the safety device 100 is restored to its inoperative state.

As described in detail above, the safety device of the present embodiment has a very simple structure and only requires one safety device 100 to be installed, so that even if either of the two air brake systems fails, the air brake on the failed side will be switched on. This system automatically shuts off the pressure air passage and maintains this state so that the air brake on the normal side can continue to operate, which has an excellent effect of further improving vehicle safety.

Furthermore, after the repair of the damaged part is completed, the safety device 100 can be returned to the non-operating state by simply releasing the pressurized air from the air reservoir, which makes the repair work easy. This is one of its features. Another embodiment of the invention is shown in FIGS. 3 and 4.

The main difference between this embodiment and the previous embodiment is in the structure of the safety device, and therefore the piping for the safety device is slightly different, but since the other parts are the same, the same parts are given the same reference numerals. will be added and the explanation will be omitted. The safety device 200 of this embodiment also serves as a Ξ-joint, and the pressure air guided from the wet tank 4 to the safety device 200 through one pipe 41 is divided into two parts within the safety device 200, and the pipe 42 , 43 to the air reservoirs 9, 14.

The pressure in the air reservoirs 9, 14 is also controlled by the lines 44, 14, respectively.
45 to the safety device 200. Safety device 20
As shown in FIG. 4, the main body 201 of
02 and large diameter portions 203 and 204 on both sides, the open ends of the large diameter portions 203 and 204 are closed by plugs 205 and 206.

A piston 207 is slidably fitted into the main body 201. The piston 207 is constructed by connecting two heads 208 and 209 with a rod 211, and the above-mentioned plug 2
Coil spring 21 installed between 05 and 206
2,213, it is normally held at the neutral position.
As a result of the piston 207 being fitted, the space within the main body 201 is divided into three chambers: a first pressure chamber 214 , a second pressure chamber 215 , and a central air chamber 216 . The pressure air guided from the boat 217 to the central air chamber 216 by the pipe 41 is divided into two parts within the central air chamber 216, one of which is connected to the boat 2.
18 toward the first air reservoir 9, and the other air from the boat 219 toward the second air reservoir 14. , 222 and the stepped surfaces 223, 224 of the main body 201, respectively.

Further, the pressure in the first air reservoir 9 is led from the boat 227 to the first pressure chamber 214 through the pipe 44, and the pressure in the second air reservoir 14 is led from the boat 228 to the second pressure chamber 215 through the pipe 45. The piston 207 is a differential piston operated by the differential pressure between the pressure chambers 214 and 215.

In the brake system configured as described above, if the air passage of the front brake system is damaged and the pressure in the first air reservoir 9 decreases, the pressure in the first pressure chamber 214 of the safety device 200 also decreases, and the piston 207 moves to the first pressure chamber 214 side, the first cutoff valve 225 is closed, and the supply of pressurized air to the first air reservoir 9 is cut off.

Also, the rear brake system was damaged and the second air reservoir 14
When the pressure decreases, the piston 207 moves toward the second pressure chamber 215, the second cut-off valve 226 is closed, and the second air reservoir 14 is separated from the compressor 1. This embodiment has the same effect as the previous embodiment, and the safety device 200 itself can serve as a Ξ-joint that divides the pressure air passage into two, so the wet tank 4
This also has the effect of reducing the number of pipes connecting the safety device 200 and the safety device 200 by one. Yet another embodiment of the invention is shown in FIG.

In this embodiment, the safety device 200 of the previous embodiment shown in FIG. 4 can be easily processed. That is, in the safety device 200 shown in FIG. 4, since the through hole drilled in the main body 201 had a small diameter portion 202 at the center, it was necessary to process the large diameter portions 203 and 204 into which the piston 207 should be fitted. However, in this embodiment, as shown in FIG. 5, the through hole 231 of the main body 201 is made into a straight hole to facilitate the processing of the main body 201, and instead a cylindrical member 232 is used. Through hole 2 is secured by C-shaped retaining rings 233 and 234.
Cut-off valves 225, 22 are fixed to the center of 31.
6 valve seats were formed.

The cylindrical member 232 has an annular groove 235 formed on its outer peripheral surface, and a hole 236 for communicating the annular groove 235 with the central air chamber 216. Since it is held by the seal rings 237 and 238, it can perform exactly the same function as the small diameter portion 202 of the through hole in the embodiment described above.
The other parts are the same as those in the previous embodiment, so their explanation will be omitted. It should be noted that in all of the embodiments shown above, the present invention was applied to air brakes of a type in which air pressure is converted to hydraulic pressure by an air feeder, but it is also possible to convert air pressure into hydraulic pressure. Of course, it is also possible to apply the present invention to a so-called full air brake in which the brake mechanism is directly actuated by air pressure, and the piping type can also be changed to the front wheel brake and the rear wheel brake as shown in the embodiment. It is not limited to the so-called two-system type, in which the front and rear piping systems are separate piping systems.

Furthermore, the above-mentioned embodiments are merely examples of the present invention, and the present invention is not limited to these embodiments, and various improvements and improvements can be made without departing from the spirit of the present invention.
It goes without saying that changes can be made.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram of a two-system air brake system including an embodiment of the present invention, and FIG. 2 is an enlarged front sectional view showing the safety device in FIG. 1. FIG. 3 is a circuit diagram of a two-system air brake system including another embodiment of the present invention, and FIG. 4 is an enlarged front sectional view showing the safety device in FIG. 3. FIG. 5 is a diagram corresponding to FIG. 4 in yet another embodiment of the present invention.
1: Compressor, 3, 8, 16: Check reverse, 9: First air reservoir, 14: Second air reservoir, 17: Brake pedal, 19: Operating valve, 22, 23:
Air booster, 24: Front wheel shilling, 32
:Rear wheel. Cylinder, 100: Safety device, 101:
Main body, 104: Piston, 115, 116: Coil spring, 125: First pressure chamber, 126: Second pressure chamber, 1
33: First cut-off valve, 136: Second cut-off valve, 200: Safety device, 201: Main body, 204: Piston, 212, 213: Coil spring, 214:
First pressure chamber, 215: Second pressure chamber, 225: First cut-off valve, 226: Second cut-off valve, 232:
Cylindrical member.

Claims (1)

[Claims] 1. Pressurized air generated by one compressor is divided into two parts and supplied to first and second air reservoirs through first and second check valves, respectively, and the first and second air reservoirs are used as a pressure source. In a two-system air brake system for a vehicle in which two air brake systems are operated independently of each other, two air brake systems facing each other are connected to a pressure air passage on the compressor side from the first and second check valves. A differential piston that receives pressure from the first and second air reservoirs on its pressure receiving surface and is actuated by the difference between the two pressures, and a holder that normally holds the differential piston in a neutral position by an elastic force. means for cutting off the pressure air passage to the first air reservoir when the pressure in the first air reservoir becomes lower than the pressure in the second air reservoir by a certain limit or more and the differential piston moves from the neutral position; When the pressure in the first cut-off valve and the second air reservoir becomes lower than the pressure of the first air reservoir by a certain limit or more and the differential piston moves from the neutral position, pressurized air is supplied to the second air reservoir. A safety device including a second cut-off valve that cuts off the passage is inserted, so that when one air brake system fails, the air brake system on the failed side is separated from the compressor. Safety device.