JPH10129447A - Antiskid device of air brake for car - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically release the limiting of the braking force of the front wheels, when the braking force of the rear wheels are lost during the travelling, by installing a rear shaft side pressure transmission piping for releasing the decompression of the compressed air of a limiting quick release valve, when the pressure of the compressed air of an air piping for a rear shaft, is lowered. SOLUTION: A rear shaft side pressure transmission piping 83 is installed between an air piping 65 for a rear shaft, and a limiting quick release valve 77, for releasing the reduction of the compressed air of the limiting quick release valve 77, when the pressure of the compressed air of the air piping 65 for a rear shaft, is lowered. When the pressure of the compressed air to be supplied to an air booster 67 for a rear shaft, is lost in a condition that the braking force of a front shaft is limited, the compressed air free form the reduction, is supplied to an air booster 63 for a front shaft from a foot brake valve 41, and the limiting of the bracking amount of the front wheels is released.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid device for an air brake for a vehicle for preventing wheels from locking and skidding during braking of the vehicle during rainy weather.

[0002]

2. Description of the Related Art Conventionally, in a vehicle such as a bus, a front brake is temporarily controlled to prevent a skid in which a front wheel is locked and the vehicle slides sideways during braking while traveling on a slippery road surface in rainy weather or the like. An anti-skid device that restricts the power to be lower than the braking force of a rear brake is widely used.

FIG. 8 shows such an anti-skid device. In this anti-skid device, between a foot brake valve 11 and a rear axle air booster 13, a rear axle air communicating therewith is provided. The pipe 15 is connected.
Further, between the foot brake valve 11 and the front axle air booster 17, a front axle air pipe 19 for communicating these components is provided.
Is connected.

[0004] A limiting quick release valve 21 is interposed in the front shaft air pipe 19. A switching valve 23 for supplying compressed air to the limiting quick release valve 21 or stopping the supply of the compressed air is arranged in the driver's seat.

FIG. 9 shows the limiting quick release valve 21 shown in FIG. 8. The limiting quick release valve 21 has a valve body 25. The valve main body 25 has an inlet port 25a to which compressed air is supplied from the foot brake valve 11 shown in FIG.

The inlet port 25a of the valve body 25
An exhaust port 25b is formed on the opposite side. In addition, the exhaust port 25 of the valve body 25
A delivery port 25c for supplying the compressed air flowing from the inlet port 25a to the front shaft air booster 17 shown in FIG. 8 is formed on the side surface on the b side.

Further, a switching port 25d to which compressed air is supplied from the switching valve 23 shown in FIG. 8 is formed on a side surface of the valve body 25 on the inlet port 25a side. The valve body 25 has a plunger 2 movably between an inlet port 25a and a delivery port 25c.
7 are accommodated. The plunger 27 has a first pressure receiving portion 27a that applies the pressure of the compressed air at the inlet port 25a to the delivery port 25c, and a pressure of the compressed air at the delivery port 25c that acts on the inlet port 25a. The second pressure receiving portion 27b having a pressure receiving area larger than the pressure receiving area of the first pressure receiving portion 27a is formed.

The plunger 27 has a switching port 2
The pressure of the compressed air supplied to 5d is changed to the delivery port 25.
A third pressure receiving portion 27c that acts on the c side is formed. At the center of the plunger 27, an air passage hole 27d penetrating in the movement direction of the plunger 27 is formed.

A valve member 2 is provided in the air passage hole 27d.
9 is movably inserted. In the valve member 29,
An inlet valve 29a is formed on the inlet port 25a side, and an exhaust valve 29b is formed on the exhaust port 25b side. Exhaust valve 2
Above 9b, a valve guide 31 is mounted.

The lower end surface of the plunger 27 and the valve guide 3
A spring 33 in a compressed state is disposed between the upper end surface of the inlet valve 1 and the plunger 27.
9a. In the above-described anti-skid device, when the brake is operated while the switching valve 23 shown in FIG. 8 is manually operated to the air supply side (normal road running), the foot brake valve 1 is switched via the switching valve 23.
1 to the third pressure receiving portion 27c of the plunger 27, and the pressure of the compressed air
Is moved to the exhaust port 25b side of the valve main body 25, whereby the exhaust valve 29b of the valve member 29 closes the exhaust port 25b,
The air passage hole 27d of the plunger 27 is opened, and the inlet port 25a and the delivery port 25c communicate.

At the same time, the foot brake valve 11
Compressed air is supplied to the inlet port 25a through the air passage hole 27d, and is supplied from the delivery port 25c to the front shaft air booster 17 shown in FIG. 8 without being decompressed. On the other hand, when the brake is operated in a state where the switching valve 23 is manually operated to the air supply stop side (slippery road surface traveling), the first of the plunger 27 from the foot brake valve 11 to the first through the inlet port 25 a of the valve body 25. Compressed air is supplied to the pressure receiving portion 27a, and the pressure of this compressed air causes the plunger 27 in which the third pressure receiving portion 27c is in the atmospheric pressure state to move to the delivery port 25c side, whereby the exhaust valve 29b of the valve member 29 is opened. At the same time as closing the exhaust port 25b, the air passage hole 27d of the plunger 27 is opened, and the inlet port 25a and the delivery port 25c are connected.

At the same time, the foot brake valve 11
Compressed air is supplied to the inlet port 25a through the air passage hole 27d. The compressed air is supplied from the delivery port 25c to the air booster 17 for the front shaft.
When the value of the product of the pressure on the pressure receiving portion 27a side and the pressure receiving area is equal to the value of the product of the pressure on the second pressure receiving portion 27b side and the pressure receiving area, and the pressure balance of the compressed air is balanced, The plunger 27 moves toward the inlet port 25a by the urging force of the spring 33, and the air passage hole 27d is closed by the inlet valve 29a.

That is, the front shaft air booster 17 includes:
Compressed air decompressed by the limiting quick release valve 21 is supplied from the foot brake valve 11, and compressed air having a pressure lower than the pressure of the compressed air supplied to the rear shaft air booster 13 is supplied from the foot brake valve 11. You. In the anti-skid device described above,
When traveling on a slippery road surface, the pressure of the compressed air supplied to the front shaft air booster 17 is reduced by manually operating the switching valve 23 to the air supply stop side. The pressure is lower than the pressure, and the braking force of the front wheels is weakened, so that a skid in which the front wheels are locked and the vehicle skids can be prevented.

[0014]

However, in the above-described conventional anti-skid device, since the braking force of the front wheels is switched only by the pressure of the compressed air in the brake system of the front wheels, the switching valve is manually moved to the air supply stop side. During operation with the front wheel braking force weakened, an abnormality occurs in the rear wheel brake system and the pressure of the compressed air decreases, and when the rear wheel braking force is lost, the braking force of the entire vehicle decreases. As a result, there is a problem that the braking distance of the vehicle may be long.

The present invention has been made to solve such a conventional problem. When the braking force of the rear wheels is lost while the vehicle is running with the braking force of the front wheels limited, the braking force of the front wheels is automatically reduced. It is an object of the present invention to provide an anti-skid device for an air brake for a vehicle, which can release the restriction described above.

[0016]

According to a first aspect of the present invention, there is provided an anti-skid device for an automobile air brake, comprising: a rear air line for communicating a foot brake valve with a rear air booster; A front shaft air pipe communicating with the shaft air booster, and a limiting quick release valve interposed in the front shaft air pipe,
Arranged in the driver's seat, supplies compressed air to the limiting quick release valve or stops supplying compressed air, and is output from the delivery port formed in the limiting quick release valve to the air booster for the front shaft. A switching valve for switching the pressure of the compressed air to be supplied to the rear shaft air pipe and the limiting quick release valve, and when the pressure of the compressed air in the rear shaft air pipe decreases, the limiting is performed. And a rear shaft-side pressure transmission pipe for releasing the pressure reduction of the compressed air of the quick release valve.

According to a second aspect of the present invention, there is provided an anti-skid device for an air brake for an automobile, wherein the limiting quick release valve is compressed on one side from the foot brake valve. A valve in which an inlet port to which air is supplied is formed and an exhaust port is formed on the other side, and the delivery port for supplying air supplied to the inlet port to the air booster for the front shaft is formed on the exhaust port side. A first pressure receiving portion that is movably housed between the main body and the inlet port and the delivery port of the valve main body, and that causes the pressure of the compressed air at the inlet port side to act on the delivery port side; , And the pressure of the compressed air on the delivery port side is A second pressure-receiving portion having a pressure-receiving area smaller than the pressure-receiving area of the first pressure-receiving portion, wherein the pressure of compressed air supplied from the switching valve is adjusted to the delivery port side. And a pressure of compressed air supplied from the rear shaft side pressure transmission pipe is made to act toward the inlet port side, and is smaller than a pressure receiving area of the third pressure receiving portion. A plunger having a fourth pressure receiving portion having a pressure receiving area, inserted into an air passage hole penetrated in the moving direction of the plunger, an inlet valve is formed on the inlet port side, and an exhaust valve is formed on the exhaust port side. A valve member, disposed between the plunger and the exhaust valve of the valve member, and connecting the valve to the exhaust port side Characterized by comprising a spring for biasing.

(Action) In the anti-skid device for an air brake for a vehicle according to the first aspect, when the brake is operated in a state where the switching valve is manually operated to the air supply side, the air booster for the front shaft is moved from the foot brake valve. Uncompressed compressed air is supplied to the air supply.On the other hand, when the brake is operated while the switching valve is manually operated to the air supply stop side, the limiting quick release valve from the foot brake valve to the rear axle air booster is used. The decompressed compressed air is supplied, and the braking force of the front wheels is limited to be weaker than the braking force of the rear wheels.

When the pressure of the compressed air in the rear axle air pipe from the rear axle pressure transmission pipe is reduced while the braking force of the front wheel is weakly limited, the decompression of the compressed air by the limiting quick release valve is reduced. Uncompressed compressed air is supplied to the air booster for the front shaft,
The restriction on the braking force of the front wheels is released. In the anti-skid device for an air brake for an automobile according to claim 2, when the brake is operated in a state where the switching valve is manually operated to the air supply side, the third pressure receiving of the plunger from the foot brake valve via the switching valve. Compressed air is supplied to the plunger via a rear axle air pipe from the foot brake valve, and at the same time, from the foot brake valve via an inlet port of the valve body. Thus, compressed air is supplied to the first pressure receiving portion of the plunger.

The plunger is moved to the exhaust port side of the valve body by the pressure of the compressed air supplied to the first pressure receiving portion, and the exhaust valve of the valve member closes the exhaust port of the valve body. The inlet valve of the member is separated from the air passage hole of the plunger, and the air passage hole is opened. As a result, the inlet port of the valve body and the delivery port are communicated,
Compressed air is supplied from the foot brake valve to the front shaft air booster via the limiting quick release valve.

At this time, the plunger is pressed against the exhaust port side of the valve body by the pressure of the compressed air supplied to the third pressure receiving portion having a pressure receiving area larger than the pressure receiving area of the fourth pressure receiving portion. The compressed air from the foot brake valve, which is kept held, is supplied to the front shaft air booster without being decompressed. On the other hand, when the brake is operated in a state where the switching valve is manually operated to the air supply stop side, compressed air is supplied from the foot brake valve to the fourth pressure receiving portion of the plunger via the rear shaft air pipe, and At the same time, compressed air is supplied from the foot brake valve to the first pressure receiving portion of the plunger via the inlet port of the valve body.

After the pressure of the compressed air supplied to the first pressure receiving portion, the plunger moves to the exhaust port side of the valve body, and the exhaust valve of the valve member closes the exhaust port of the valve body. The inlet valve of the member is separated from the air passage hole of the plunger, and the air passage hole is opened. As a result, the inlet port of the valve body and the delivery port are communicated,
Compressed air is supplied from the foot brake valve to the front shaft air booster via the limiting quick release valve, and the product of the pressure of the second pressure receiving portion and the pressure receiving area, the pressure of the fourth pressure receiving portion, and the pressure receiving area. When the value obtained by adding the product of the pressure and the product of the pressure of the first pressure receiving portion and the pressure receiving area becomes equal, the pressure of the compressed air on the front shaft air booster side increases, and the foot brake The pressure balance between the pressure of the compressed air on the valve side and the pressure of the compressed air on the front air booster side is in a balanced state, and the plunger moves to the inlet port side by the biasing force of the spring, and enters the air passage hole into the inlet. The valve abuts and the air passage hole is closed.

That is, the compressed air decompressed by the limiting quick release valve is supplied from the foot brake valve to the front air booster via the limiting quick release valve, and the rear air booster is supplied from the foot brake valve. Is supplied at a pressure lower than that of the compressed air supplied to the vehicle, and the braking force of the front wheels is limited to be weaker than the braking force of the rear wheels.

When the pressure of the compressed air supplied to the rear shaft air booster is lost while the braking force of the front shaft is limited, the inflow of compressed air from the rear shaft side pressure transmission pipe Stops, the fourth pressure receiving portion of the plunger is in the atmospheric pressure state, the force for pressing the plunger against the inlet port side is lost, and the pressure receiving area of the first pressure receiving portion on the side of the foot brake valve is reduced to the second pressure on the side of the front shaft air booster. Is larger than the pressure receiving area of the pressure receiving portion, the plunger is pressed to the exhaust port side of the valve body, and the compressed air that has not been depressurized is supplied from the foot brake valve to the air booster for the front shaft, and the braking force of the front wheel is increased. The restrictions are lifted.

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an embodiment (corresponding to claims 1 and 2) of an anti-skid device for a vehicle air brake according to the present invention. In the drawing, reference numeral 41 denotes a foot brake valve.

In this embodiment, the foot brake valve 41 is arranged in a driver's seat of a bus. The foot brake valve 41 has a front shaft valve portion 41A and a rear shaft valve portion 41B.

The first shaft valve portion 41A is provided with a first
A front shaft air tank 45 is connected via an air pipe 43. A rear shaft air tank 49 is connected to the inflow side of the rear shaft valve portion 41B via a second air pipe 47. Front shaft air tank 45 and rear shaft air tank 4
A communication pipe 51 for connecting these components is connected between the communication pipe 9.

A main air tank 55 is connected to the communication pipe 51 via a third air pipe 53. An air compressor 59 is connected to the main air tank 55 via an air dryer 57. Front shaft valve part 4
The first front shaft air pipe 61A and the second front shaft air pipe 61A
The front air booster 63 is connected to the front shaft air pipe 61B.

The rear shaft air booster 6 is connected to the outflow side of the rear shaft valve portion 41B via a rear shaft air pipe 65.
7 is connected. The front shaft air booster 63 and the rear shaft air booster 67 have a function of amplifying the pressure of the supplied air and converting it to a hydraulic pressure, and supplying the hydraulic pressure to a front brake 71 and a rear brake 75 described later. ing.

A pair of front brakes 71 is connected to the front shaft air booster 63 via a front shaft hydraulic pipe 69. A pair of rear brakes 75 is connected to the rear shaft air booster 67 via a rear shaft hydraulic pipe 73. A limiting quick release valve 77 is arranged between the first front shaft air pipe 61A and the second front shaft air pipe 61B.

One end of the first front shaft air pipe 61A is connected to the outflow side of the front shaft valve portion 41A.
The other end of the first front shaft air pipe 61A is connected to an inlet port 91a of the limiting quick release valve 77, which will be described later. One end of the second front shaft air pipe 61B is connected to a delivery port 91d of the limiting quick release valve 77, which will be described later.

The other end of the second front shaft air pipe 61B is connected to the air inflow side of the front shaft air booster 63. A switching valve 79 manually operated by a driver is disposed between the foot brake valve 41 and the limiting quick release valve 77.
An inlet port 91a of the switching valve 79 has a first end connected to the first front shaft air pipe 61A.
The other end of the switching pipe 81A is connected.

The delivery port 9 of the switching valve 79
1d is connected to the other end of the second switching pipe 81B whose one end is connected to a later-described switching port 91e of the limiting quick release valve 77. A rear shaft side pressure transmission pipe 83 is disposed between the rear shaft air pipe 65 and the limiting quick release valve 77.

One end of the rear shaft side pressure transmission pipe 83 is connected to the rear shaft air pipe 65, and the other end is connected to a check port 91f of the limiting quick release valve 77, which will be described later. Have been. FIG.
1 shows the limiting quick release valve 77 shown in FIG. 1. The limiting quick release valve 77 has a valve body 91.

The valve body 91 is formed by casting a metal material. An inlet port 91a to which the other end of the first front shaft air pipe 61A shown in FIG. 1 is connected is formed on the upper surface of the valve main body 91 in the drawing.

An exhaust port 91b is formed on the lower surface of the valve main body 91 in the drawing. Inside the exhaust port 91b, there is formed an exhaust valve seat 91c having a tapered shape expanding inward. Also,
A delivery port 91d to which one end of the second front shaft air pipe 61B shown in FIG. 1 is connected is formed below the right side surface of the valve body 91 in the drawing.

Further, a switching port 91e to which one end of the second switching pipe 81B shown in FIG. 1 is connected is formed above the right side surface of the valve body 91 in the drawing. In the vicinity of the center of the right side surface of the valve body 91 in FIG.
Is formed with a check port 91f to which the other end of the rear shaft-side pressure transmission pipe 83 shown in FIG. In this embodiment, tapered pipe threads are formed on the inner peripheral surfaces of the inlet port 91a, the exhaust port 91b, the delivery port 91d, the switching port 91e, and the check port 91f.

The valve body 91 houses a plunger 93 made of a metal material. This plunger 93 is
The cross section is formed in a circular shape, and the valve body 91
Are arranged so as to be movable in the axial direction. Plunger 9
3, a first pressure receiving portion 93a communicating with the inlet port 91a is formed.

Further, a second pressure receiving portion 93b communicating with the exhaust port 91b and the delivery port 91d is formed on the lower surface of the plunger 93 in the drawing. The pressure receiving area of the second pressure receiving portion 93b is smaller than the pressure receiving area of the first pressure receiving portion 93a. Plunger 9
In the vicinity of the center of the outer peripheral surface of No. 3, an annular annular convex portion 93c is formed.

The inlet port 9 of the annular projection 93c
A third pressure receiving portion 93d communicating with the switching port 91e is formed on the end surface on the 1a side. Also, the annular convex portion 93c
A fourth pressure receiving portion 93e communicating with the check port 91f is formed on the end face on the side of the delivery port 91d. The pressure receiving area of the fourth pressure receiving section 93e is smaller than the pressure receiving area of the third pressure receiving section 93d.

The sum of the pressure receiving area of the second pressure receiving portion 93b and the pressure receiving area of the fourth pressure receiving portion 93e is larger than the pressure receiving area of the first pressure receiving portion 93a. A first seal ring groove 93f is formed on the outer peripheral surface of the plunger 93 on the side of the first pressure receiving portion 93a.
A first seal ring 95 made of a rubber material is mounted in the seal ring groove 93f.

Further, a second seal ring groove 93g is formed on the outer peripheral surface of the plunger 93 on the side of the second pressure receiving portion 93b, and the second seal ring groove 93g is made of a rubber material. The second seal ring 97 is mounted. Further, a third seal ring groove 93h is formed on the outer peripheral surface of the annular convex portion 93c of the plunger 93,
A third seal ring 99 made of a rubber material is mounted in the third seal ring groove 93h.

At the center of the plunger 93, an air passage hole 93i penetrating through the first pressure receiving portion 93a and the second pressure receiving portion 93b is formed concentrically. Air passage hole 93i
On the first pressure receiving portion 93a side, a valve accommodating portion 93j having an inner diameter larger than the inner diameter of the air passage hole 93i is formed concentrically. Between the air passage hole 93i and the valve accommodating portion 93j, a tapered inlet valve seat 93k connecting the inner peripheral surface of the air passage hole 93i and the inner peripheral surface of the valve accommodating portion 93j is formed.

The valve member 101 is movably inserted into the air passage hole 93i. The valve member 101 has a valve stem 103 made of a metal material.
A spherical inlet valve 105 made of a rubber material is mounted at the end on the a side.

A spherical exhaust valve 107 made of a rubber material is attached to the end of the valve stem 103 on the exhaust port 91b side. An annular valve guide 109 made of a metal material is fitted on the exhaust valve 107 side of the valve stem 103.
Valve guide 109 and second pressure receiving portion 9 of plunger 93
3b, a compressed spring 111 is sandwiched.

In the above-described anti-skid device for an air brake for a vehicle, when the brake is operated in a state where the switching valve 79 arranged in the driver's seat is manually operated to the air supply side, as shown in FIG. Switching valve 79 shown in FIG.
From the foot brake valve 41 to the plunger 93
Compressed air is supplied to the third pressure receiving portion 93d of the plunger 93, and compressed air is supplied from the foot brake valve 41 to the fourth pressure receiving portion 93e of the plunger 93 via the rear shaft air pipe 65. Compressed air is supplied from the brake valve 41 to the first pressure receiving portion 93a of the plunger 93 via an inlet port 91a of the valve body 91.

The plunger 93 is moved by the pressure of the compressed air supplied to the first pressure receiving portion 93a.
1, the exhaust valve 107 of the valve member 101 is moved to the exhaust port 91b side.
After closing the exhaust port 91b by contacting the exhaust valve seat 91c, the inlet valve 105 of the valve member 101 is separated from the inlet valve seat 93k of the plunger 93 to open the air passage hole 93i.

Thus, the inlet port 91a of the valve body 91 and the delivery port 91d are communicated, and compressed air is supplied from the foot brake valve 41 to the air booster 63 for the front shaft via the limiting quick release valve 77.

At this time, the plunger 93 is pressed toward the exhaust port 91b of the valve body 91 by the pressure of the compressed air supplied to the third pressure receiving portion 93d having a pressure receiving area larger than the pressure receiving area of the fourth pressure receiving portion 93e. The compressed air from the foot brake valve 41 is supplied to the front shaft air booster 63 without being decompressed.

When the brake operation is stopped, as shown in FIG. 4, the first pressure receiving portion 93a, thirdly, the pressure receiving portion 93a,
The fourth pressure receiving portion 93e is brought into the atmospheric pressure state, and the compressed air supplied to the front shaft air chamber flows back to the limiting quick release valve 77, and the exhaust port 9
Compressed air is supplied from 1b to the second pressure receiving portion 93b, and the pressure of the compressed air moves the plunger 93 to the inlet port 91a side, so that the exhaust valve 107 is separated from the exhaust valve seat 91c of the valve body 91,
The exhaust port 91b is opened, and the compressed air supplied to the front shaft air booster 63 is discharged.

On the other hand, when the brake is operated with the switching valve 79 manually operated to the air supply stop side, the plunger 93 is connected from the foot brake valve 41 through the rear shaft air pipe 65 as shown in FIG. Of the fourth pressure receiving portion 93e
Is supplied to the inlet port 91a of the valve body 91 from the foot brake valve 41 at the same time.
The compressed air is supplied to the first pressure receiving portion 93a of the plunger 93 via the.

The plunger 93 is moved by the pressure of the compressed air supplied to the first pressure receiving portion 93a.
1, the exhaust valve 107 of the valve member 101 is moved to the exhaust port 91b side.
After closing the exhaust port 91b by contacting the exhaust valve seat 91c, the inlet valve 105 of the valve member 101 is separated from the inlet valve seat 93k of the plunger 93 to open the air passage hole 93i.

As a result, the inlet port 91a of the valve body 91 and the delivery port 91d communicate with each other, and compressed air is supplied from the foot brake valve 41 to the front shaft air booster 63 via the limiting quick release valve 77. 2, the value obtained by adding the value of the product of the pressure of the pressure receiving portion 93b and the pressure receiving area, the value of the product of the pressure of the fourth pressure receiving portion 93e and the pressure receiving area, and the pressure and the pressure receiving area of the first pressure receiving portion 93a. As shown in FIG. 6, the pressure of the compressed air on the front shaft air booster 63 increases, and the pressure of the compressed air on the foot brake valve 41 side and the pressure of the front shaft air booster increase. The pressure balance with the pressure of the compressed air on the 63 side is balanced, and the plunger 93 moves to the inlet port 91a side by the urging force of the spring 111, and Valve 105 inlet valve seat 93
The air passage hole 93i is closed by abutting on k.

That is, the front shaft air booster 63
Compressed air decompressed by the limiting quick release valve 77 is supplied from the foot brake valve 41 via the limiting quick release valve 77, and the compressed air supplied from the foot brake valve 41 to the rear shaft air booster 67 is smaller than the compressed air supplied to the rear shaft air booster 67. Low pressure compressed air is supplied, and the braking force of the front wheels is limited to be weaker than the braking force of the rear wheels.

When the pressure of the compressed air supplied to the rear shaft air booster 67 is lost while the braking force of the front shaft is restricted, as shown in FIG. 4, the pressure receiving portion 93e is in an atmospheric pressure state, the force for pressing the plunger 93 against the inlet port 91a is lost, and the pressure receiving area of the first pressure receiving portion 93a on the foot brake valve 41 side is the second pressure receiving portion on the front shaft air booster 63 side. Is larger than the pressure receiving area of the pressure receiving portion 93b, the plunger 93 is connected to the exhaust port 91b of the valve body 91.
Side, and the foot brake valve 41
Compressed air that has not been depressurized from the front shaft air booster 6
3 and the restriction on the braking force of the front wheels is released.

In the anti-skid device for an air brake for an automobile configured as described above, the air pipe 65 for the rear shaft and the limiting quick release valve 77
When the pressure of the compressed air in the rear shaft air pipe 65 decreases,
Since the rear shaft side pressure transmission pipe 83 for releasing the decompression of the compressed air of the limiting quick release valve 77 is arranged, when the braking force of the front wheel is limited and the braking force of the rear wheel is lost during traveling, the automatic transmission is automatically performed. The restriction on the braking force of the front wheels can be released.

The first pressure receiving portion 93a for applying the pressure of the compressed air at the inlet port 91a toward the delivery port 91d, and the pressure of the compressed air at the delivery port 91d toward the inlet port 91a. A third pressure receiving portion 93b having a pressure receiving area smaller than the pressure receiving area of the first pressure receiving portion 93a, and causing the pressure of the compressed air supplied from the switching valve 79 to act on the delivery port 91d side. Of the compressed air supplied from the pressure receiving portion 93d and the rear shaft air pipe 65 toward the inlet port 91a side, and the third pressure receiving portion 93
The fourth pressure receiving portion 93 having a pressure receiving area smaller than the pressure receiving area d.
e, the plunger 93 is movably accommodated between the inlet port 91a and the delivery port 91d of the valve main body 91. Therefore, the pressure drop of the compressed air supplied to the rear shaft air booster 67 reduces The decompression of the compressed air at 77 can be released, and the restriction on the braking force of the front wheels can be automatically released with a simple structure without any other power source.

In the above-described embodiment, an example in which the present invention is applied to a bus has been described. However, the present invention is not limited to such an embodiment, and the present invention is applied to a vehicle equipped with an air brake device. A wide range of anti-skid devices for automobile air brakes can be widely applied, and in particular, a sufficient effect can be obtained by applying the present invention to a route bus in which the load on the front shaft varies greatly due to the movement of passengers in the vehicle.

[0059]

As described above, in the anti-skid device for an automobile air brake according to the first aspect, the compressed air of the rear shaft air piping is provided between the rear shaft air piping and the limiting quick release valve. When the pressure of
The rear axle pressure transmission pipe that releases the decompression of the compressed air from the limiting quick release valve is located, so when the braking force on the front wheels is limited and the braking force on the rear wheels is lost while driving, the front wheels are automatically turned off. Can be released from the restriction on the braking force.

In the anti-skid device for an air brake for a vehicle according to the second aspect, the first pressure receiving portion for applying the pressure of the compressed air at the inlet port toward the delivery port, and the pressure of the compressed air at the delivery port. To the inlet port side, and has a second pressure receiving portion having a pressure receiving area smaller than the pressure receiving area of the first pressure receiving portion, and directs the pressure of the compressed air supplied from the switching valve toward the delivery port side. The pressure of the compressed air supplied from the third pressure receiving portion to be operated and the compressed air supplied from the rear shaft side pressure transmission pipe is applied toward the inlet port side, and the fourth pressure receiving area having a pressure receiving area smaller than the pressure receiving area of the third pressure receiving portion. Since the plunger having the pressure receiving portion is movably housed between the inlet port and the delivery port of the valve body, the compressed air supplied to the rear shaft air booster is The force reduction, limiting quick can release the pressure reduction of the compressed air release valve, without the need for any other power source, it is possible to automatically remove the restriction of the front wheel braking force with a simple structure.

[Brief description of the drawings]

FIG. 1 is a piping diagram showing an embodiment of an anti-skid device for an air brake for a vehicle according to the present invention.

FIG. 2 is a sectional view showing the limiting quick release valve of FIG. 1;

FIG. 3 is a sectional view showing an air supply state when the limiting quick release valve of FIG. 2 is not limited.

FIG. 4 is a cross-sectional view showing an exhaust state of the limiting quick release valve of FIG. 2;

FIG. 5 is a cross-sectional view showing an air supply state when the limiting quick release valve of FIG. 2 is restricted.

FIG. 6 is a cross-sectional view showing a balancing state of the limiting quick release valve continued from FIG. 5;

FIG. 7 is a cross-sectional view showing an air supply state when the pressure of a check port is reduced when the limiting quick release valve of FIG. 2 is restricted.

FIG. 8 is a piping diagram showing a conventional anti-skid device.

FIG. 9 is a sectional view showing the limiting quick release valve of FIG. 8;

[Explanation of symbols]

 41 Foot Brake Valve 61A First Front Shaft Air Pipe 61B Second Front Shaft Air Pipe 63 Front Shaft Air Booster 65 Rear Shaft Air Pipe 67 Rear Shaft Air Booster 77 Limiting Quick Release Valve 79 Switching Valve 83 Rear shaft side pressure transmission pipe 91a Inlet port 91b Exhaust port 91d Delivery port 93 Plunger 93a First pressure receiving part 93b Second pressure receiving part 93d Third pressure receiving part 93e Fourth pressure receiving part 93i Air passage hole 101 Valve member 105 Inlet Valve 107 Exhaust valve 111 Spring

Claims (2)

[Claims] 1. A rear-shaft air pipe for communicating a foot brake valve with a rear-shaft air booster; a front-shaft air pipe for communicating the foot brake valve with a front-shaft air booster; A limiting quick release valve interposed in the air pipe; and a compressed air supplied to the limiting quick release valve, which is arranged in the driver's seat, or supplied to the limiting quick release valve to stop the supply of the compressed air to form the limiting quick release valve. A switching valve for switching the pressure of the compressed air output from the delivery port to the front shaft air booster; and a rear shaft air disposed between the rear shaft air pipe and the limiting quick release valve. When the pressure of the compressed air in the piping decreases, the compressed air of the limiting quick release valve is reduced. It is provided with a shaft-side pressure transmitting pipe after to release the anti-skid device of the air brake for a motor vehicle, characterized in. 2. The anti-skid device for an air brake for a vehicle according to claim 1, wherein the limiting quick release valve has an inlet port formed on one side to be supplied with compressed air from the foot brake valve, and has an inlet port formed on the other side. An exhaust port formed therein, wherein the delivery port for supplying the air supplied to the inlet port to the front shaft air booster is formed on the exhaust port side; and the inlet port of the valve body and the delivery. A first pressure-receiving portion that is movably accommodated between the port and the pressure of the compressed air at the inlet port toward the delivery port, and the pressure of the compressed air at the delivery port is Operate toward the inlet port side to receive the first pressure receiving portion. A third pressure receiving portion having a pressure receiving area smaller than the pressure area, the third pressure receiving portion for applying the pressure of the compressed air supplied from the switching valve toward the delivery port side, and the rear shaft side pressure; A plunger having a fourth pressure receiving portion having a pressure receiving area smaller than a pressure receiving area of the third pressure receiving portion by applying a pressure of compressed air supplied from a transmission pipe toward the inlet port side, and moving the plunger. A valve member having an inlet valve formed on the inlet port side and an exhaust valve formed on the exhaust port side, between the plunger and the exhaust valve of the valve member. And a spring for urging the valve toward the exhaust port. Anti-skid device of the air brake for the car.