JPH11189147A - Brake system for multiaxle trailer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance brake releasing responsiveness at brake operation releasing time, and prevent the drag of a brake by arranging a valve device switched to the state of communicating only the antiskid control valve side to output high pressure on the basis of the occurrence of a difference in output pressure between a pair of antiskid control valves. SOLUTION: When an antiskid control valve 7b is actuated since a lock tendency is caused in a front axle side left wheel 2b, higher one among delivery pressures from a pair of antiskid control valves 7a and 7b is selected by a valve device 15 to be supplied to brake chambers 13a and 13b. Since brake pressure supplied to rear axle 3 side brake chambers 13a and 13b at brake releasing operation time can be instantly released through the valve device 15, the responsiveness of brake releasing operation can be enhanced. Therefore, the acceleration of a vehicle is not hindered since a brake is dragged when accelerated just after braking the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a load on a plurality of axles arranged in the front-rear direction of a vehicle (hereinafter referred to as "axle load").
The present invention relates to a brake system for a multi-axle trailer that controls a braking force applied to the left and right wheels of each axle so as not to lock the wheels, for a multi-axle trailer that changes during braking.

[0002]

2. Description of the Related Art Conventionally, as a brake system for a multi-axle trailer, in controlling the braking force of each of the left and right wheels in a plurality of axles, each of the followers that applies a brake to each wheel is controlled by the rotation state of the wheel. It is common to provide an anti-skid control valve that controls the supply pressure accordingly. However, in this configuration, since a sensor for detecting the rotation state of the wheel and the anti-skid control valve are provided for all the wheels, the number becomes large, and the system configuration becomes complicated.

For this reason, recently, a sensor and an anti-skid control valve for detecting the rotation state of the wheels are provided for the left and right wheels of the plurality of axles, which have the lightest axle weight during braking and are likely to lock the wheels. The brake pressure is controlled directly (hereinafter, referred to as “direct control”), and the brake pressure on the left and right wheels having the highest axle load during braking and hardly locking the wheel is determined by the above anti-skid. 2. Description of the Related Art A technique has been developed in which a valve for adjusting a control pressure of a control valve to a predetermined pressure is provided to perform indirect control (hereinafter, referred to as “indirect control”). According to this technology, the number of sensors and anti-skid control valves can be reduced by the amount of indirect control, and the system configuration can be simplified.

One of such techniques is disclosed in Japanese Patent Laid-Open No. 7-4 / 1994.
No. 0825 discloses a brake control device for a trailer equipped with a tandem axle by a rocker arm type suspension system. Hereinafter, this will be described with reference to FIG.

FIG. 2 is a piping configuration diagram showing a brake system on the trailer side described in the above publication. The trailer has a front axle 2 and a rear axle 3 configured as rocker arm suspension type tandem axles in the front-rear direction of the vehicle, and the wheels 2a, 2b and 3a, 3a, 3a, 3
For b, brake chambers 12a and 12b and 13a and 13b as followers are provided. In the brake chambers 12a and 12b for the wheels 2a and 2b of the front shaft 2, air pressure discharged from a brake valve disposed on a tractor (not shown) in response to a driver's brake operation constitutes a service line. The brake chambers 13a, 13b for the wheels 3a, 3b of the rear shaft 3 are supplied through a pipe 4, a relay emergency valve 9, a pipe 8, and an anti-skid control valve 7a, 7b. From the anti-skid control valves 7a, 7b to the flow control valves 30a, 30b
The air pressure is supplied via the. Each of the flow control valves 30a and 30b includes a check valve 31 that allows only air pressure flow from the anti-skid control valves 7a and 7b toward the brake chambers 13a and 13b, and a throttle passage provided in parallel with the check valve 31. 32. In the drawing, reference numeral 6 denotes a conduit constituting an emergency line, reference numeral 10 denotes an air tank connected to the relay emergency valve 9, and the relay emergency valve 9 functions as a relay valve and for some reason. When the emergency line 6 is damaged, it has a function of automatically applying a brake to the trailer.

[0006] The tandem axle of the rocker arm type suspension system has a characteristic that the load on the front shaft 2 is reduced due to load movement during braking, and that the rear shaft 3 is heavier. A difference in braking force is generated between the motor and the rear shaft 3. Therefore, in order to prevent the wheels 2a, 2b of the front shaft 2 from being locked during braking, the front shaft 2 is provided with a pair of wheel speed sensors 5a, 5b for detecting the rotation speed of each wheel 2a, 2b. , The anti-skid control valves 7a and 7b are controlled based on the output signals of the pair of wheel speed sensors 5a and 5b.
a, 2b is activated in response to the tendency to lock,
The brake pressure supplied to each of the followers 12a and 12b is individually adjusted. Wheels 3a of the rear shaft 3,
The same air pressure as the brake chambers 12a, 12b on the front shaft 2 side, which is controlled by the anti-skid control valves 7a, 7b, is supplied to the brake chambers 13a, 13b for the 3b via the flow control valves 30a, 30b. .

On the other hand, for example, when the anti-skid control valve 7a is switched to the brake pressure release mode due to the tendency of locking of the front axle right wheel 2a, the air pressure supplied to the brake chamber 13a for the rear axle right wheel 3a is reduced. The brake release speed is reduced by returning the control valve 30a through the throttle passage 32, so that the anti-skid control valve 7a does not completely lose the braking force before the mode is switched to the braking mode. Insufficient braking force is applied to the rear right wheel 3a.

[0008]

However, in the brake system described in the above publication, the check valve 31 and the non-return valve 31 are used in order to eliminate the insufficient braking force of the wheels 3a and 3b of the rear shaft 3 which is the object of the indirect control. Since the flow control valves 30a and 30b composed of the throttle passages 32 are provided, when the driver depresses the accelerator pedal immediately after releasing the brake operation by removing the pedaling force on the brake pedal to accelerate the vehicle, the rear shaft 3 Are dragged by the residual pressure of the brake pressure. That is, there is a problem that the responsiveness of the vehicle acceleration operation is reduced. Also,
Anti-skid control valves 7a, 7b and brake chamber 1
3a, 13b, respectively, the flow control valve 30a,
It is necessary to provide 30b, which complicates the system configuration.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and is directed to a brake system for performing direct control and indirect control on a plurality of axles arranged in the front-rear direction of a vehicle. Provided is a brake system for a multi-axle trailer, which can improve the responsiveness of a brake operation release while simplifying a brake operation while eliminating insufficient braking force during anti-skid control on wheels, and can simplify the system configuration as compared with the conventional brake system. As an issue.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a brake system for a multi-axle trailer having a plurality of axles arranged in the longitudinal direction of the vehicle, each having left and right wheels. A follower to which a brake pressure is supplied in accordance with the brake operation is provided, and among the plurality of axles, the axle with the lightest axle load during braking is provided with a pair of sensors for detecting the rotational speed of each of the left and right wheels, A pair of anti-skid control valves that operate in response to the tendency of the wheels to lock based on the output signals of the pair of sensors and individually adjust the brake pressure supplied to the followers of each of the left and right wheels. In the brake system for an axle trailer, at least one of the pair of anti-skid control valves is provided for two of left and right followers of the axle having the heaviest axle load during braking among the plurality of axles. A valve device is provided that switches from a state of communication to a state in which only the anti-skid control valve that outputs high pressure communicates based on a difference in output pressure between the pair of anti-skid control valves. Solved by a brake system for a multi-axle trailer.

According to the present invention, a state in which at least one of a pair of anti-skid control valves communicates with two followers of left and right wheels of an axle having the heaviest axle load during braking among a plurality of axles, By providing a valve device that switches to a state in which only the anti-skid control valve that outputs high pressure is communicated based on the difference in output pressure between the anti-skid control valves, the braking force on the left and right wheels during the anti-skid control is provided. While eliminating the shortage, the brake release responsiveness at the time of release of the brake operation is enhanced to prevent the brake from being dragged, and to simplify the entire brake system.

[0012]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a piping system diagram of a brake system for a multi-axle trailer according to an embodiment of the present invention. In the figure, parts corresponding to those in FIG. 2 are denoted by the same reference numerals. The trailer has a front axle 2 and a rear axle 3 configured as rocker arm suspension type tandem axles in the front-rear direction of the vehicle, and the front axle 2 and the rear axle 3 have wheels 2a, 2b and 3a, 3b. Respectively, the brake chamber 12 as a follower
a, 12b and 13a, 13b. In the brake chambers 12a and 12b for the wheels 2a and 2b of the front shaft 2, air pressure discharged from a brake valve disposed on a tractor (not shown) in response to a driver's braking operation is a pipe forming a service line. The power is supplied through the line 4, the relay emergency valve 9, the line 8, and the anti-skid control valves 7a and 7b. Air pressure is supplied to the brake chambers 13a and 13b for the wheels 3a and 3b of the rear shaft 3 from the anti-skid control valves 7a and 7b via a valve device 15 described later. The anti-skid control valves 7a and 7b are actuated by control commands from a control unit (not shown) based on the outputs of wheel speed sensors 5a and 5b for detecting the rotation speed of each wheel 2a and 2b of the front shaft 2.

The valve device 15 includes an upper body 17 having an inlet 21a formed through one of the pair of anti-skid control valves 7a, 7b and connected to the anti-skid control valve 7a through a pipe 14a, and the other anti-skid control valve 7a, 7b. An inlet 21b connected to the skid control valve 7b via a pipe 14b, and a pipe 1
A lower body 16 formed with a pair of outlets 22a, 22b connected to the brake chambers 13a, 13b for the respective wheels 3a, 3b of the rear axle 3 via the rear body 1a, 11b. Is gasket 25
Are integrated by being screwed through. Inside the pair of inlets 21a, 21b and outlets 22a, 22
a movable body 1 having a valve body 19a made of rubber or synthetic resin in this inner hole 26.
9 are arranged. The movable body 19 is slidably inserted into an inner peripheral surface of the valve guide cylinder 18 which is supported between the lower main body 16 and the upper main body 17 in the inner hole 26 and has a plurality of ventilation holes 18a formed in a side peripheral portion. ing.

The movable body 19 is connected to the pair of entrances 21a, 21a.
b can be moved in accordance with the difference in air pressure introduced into the pair of outlets 22a, 22b.
Of the valve guide cylinder 18 and the other
8a and the outlets 22a, 22b through an annular space between the inner hole 26 and the valve guide cylinder 18. If the air pressure introduced into the pair of inlets 21a and 21b is the same, the movable body 19 receives the pressure and the valve guide cylinder 18
To make the inlet 21a and / or 21b communicate with both outlets 22a and 22b. That is, in this case, the two exits 22a, 22b
From which the entrance 21a is blocked (see FIG. 1) or
In the opposite position, the entrance 21b is blocked, or both entrances 21
There is a state of taking three positions, i.e., positions where a and 21b communicate with both outlets 22a and 22b. Here, in the state shown in FIG. 1, as described later, since the air pressure introduced into the other inlet 21b is higher than the air pressure introduced into the other inlet 21a, the movable body 19 is moved to the one inlet 21a. Move to the side,
The valve body 19a closes the inlet 21a and the outlets 22a, 2a.
2b and the other inlet 21b is connected to the outlet 22
a and 22b are shown in communication.

The embodiment of the present invention is configured as described above. Next, this operation will be described.

Now, the vehicle is in a running state, the brake pressure is not supplied to each wheel, and the movable body 19 of the valve device 15 is moved to an arbitrary position in the valve guide cylinder 18 due to the influence of the vibration of the vehicle and the like. is there. When the driver performs a brake operation by depressing the brake pedal, air pressure is introduced from a brake valve (not shown) on the tractor side to the pipeline 8 via the service line 4 and the relay emergency valve 9, and the anti-skid Control valve 7a,
7b, brake chambers 12a, 12 on the front shaft 2 side.
Air pressure is introduced into b. The air pressure from the brake valve is supplied from the pipe 8 to the anti-skid control valve 7a,
7b and to the valve device 15 via lines 14a, 14b. At this time, since the anti-skid control is not performed, equal discharge pressures from the anti-skid control valves 7a and 7b are introduced into the inlets 21a and 21b, and the movable body 19 in the valve device 15 receives the above-mentioned arbitrary pressure. And the discharge pressure communicates with the outlets 22a and 22b. As a result, the pipes 11a, 1
1b, the brake chambers 13a, 13 on the rear shaft 3 side
Air pressure is introduced into b. As described above, a known braking operation is performed.

During the brake control, for example, a tendency to lock the front axle right wheel 2a is detected, and an anti-skid control command is issued from the control unit (not shown) to the anti-skid control valve 7a. This anti-skid control command is
The command is composed of a brake pressure release command, a brake pressure holding command, and a brake pressure command, and any one of them is issued by a predetermined control program according to the rotation state of the wheel 2a. Therefore, when the anti-skid control valve 7a is switched to the brake pressure release mode and the brake pressure release control is performed on the front axle right wheel 2a showing the lock tendency, the other brake in the normal brake pressure holding mode is performed. Since the air pressure output from the anti-skid control valve 7b is higher, the movable body 19 in the valve device 15 is pushed by the output pressure of the anti-skid control valve 7b and moves along the valve guide tube 18 toward the inlet 21a. The valve body 19 is moved as shown in FIG.
a closes the inlet 21a and cuts off the communication between the inlet 21a and the inside of the inner hole 26. Thereby, the anti-skid control valve 7
b is a pair of outlets 22a, 22b of the valve device 15.
And, it is supplied to the brake chambers 13a, 13b on the rear shaft 3 side via the pipes 11a, 11b.

Thereafter, when the other front axle-side left wheel 2b tends to lock and the anti-skid control valve 7b operates,
The higher of the discharge pressures from the pair of anti-skid control valves 7a and 7b is selected by the valve device 15 and supplied to the brake chambers 13a and 13b. For example, when one anti-skid control valve 7a is in the brake pressure holding mode and the other anti-skid control valve 7b is in the brake pressure release mode, the anti-skid control valve 7a in the brake pressure holding mode is set. Since the discharge pressure side is higher, the movable body 19 in the valve device 15 moves downward in the figure to close the inlet 21b,
The discharge pressure of the anti-skid control valve 7a is supplied to the brake chambers 13a and 13b on the rear shaft 3 side.

As described above, the front shaft 2 to be directly controlled is
While the anti-skid control is performed due to the tendency of the wheels 2a, 2b on the side to be locked, the rear shaft 3 to be subjected to indirect control is controlled.
Insufficient braking force on the side wheels 3a, 3b is prevented.

When the brake operation is released by the driver removing the pedaling force on the brake pedal, the brake pressure supplied to the trailer side is reduced by the relay emergency valve 9.
Exhausted to the atmosphere. At this time, the brake pressure supplied to the brake chambers 13a and 13b on the rear shaft 3 side returns to the relay emergency valve 9 via the inlet 21a or 21b of the valve device 15, or both.

At this time, according to the present embodiment, the brake chambers 13a, 13a,
The brake pressure supplied to 3b can be immediately released via the valve device 15, and the responsiveness of the brake release operation can be improved. Therefore, when the vehicle is accelerated immediately after being braked, the brake is not dragged as in the related art, and the acceleration of the vehicle is not hindered. Also, unlike the related art, there is no need to provide flow control valves including throttles between the anti-skid control valves 7a, 7b and the brake chambers 13a, 13b on the rear shaft 3, so that the brake system is simplified compared to the related art. Can be achieved.

Further, according to the present embodiment, the valve device 15
Is a type that operates by receiving a differential pressure between the output pressures of the anti-skid control valves 7a and 7b, so that there is no need to separately provide a command mechanism for performing high-pressure side selection switching.
The brake system can be simplified. Further, the valve device 15 includes a pair of anti-skid control valves 7a,
When the pipe 7b is connected to the brake chambers 13a and 13b on the rear shaft 3 side, the connector can also be used as a connector for forming a junction / branch portion of the pipe, thereby also simplifying the brake system. .

Although the embodiments of the present invention have been described above, the present invention is, of course, not limited thereto, and various modifications can be made based on the technical concept of the present invention.

For example, in the above embodiment, the valve device 15
The movable body 19 is supported in the valve guide cylinder 18 in a free state. Alternatively, when the valve device 15 is not operated, the movable body 1
9 is positioned at the middle of the valve guide cylinder 18 so that
A relatively weak spring that urges the movable body 19 with the same load may be stretched inside the entrance 21b, 21a opposite from both the entrance 21a and the entrance 21b. Thus, unnecessary movement of the movable body 19 due to vibration or the like during traveling of the vehicle when the valve device is not operated can be limited.

In the above embodiment, the brake system having the front and rear axles 2 and 3 of the rocker arm type suspension system has been described. Of course, the brake system having the front and rear axles adopting the non-rocker arm type suspension system will be described. It is also possible to apply.

In the above embodiment, the valve device 15
A pair of outlets 22a, 22b are formed in the main body of the brake chamber 13a.
The conduit connected to the outlet may be bifurcated to communicate with 13b.

[0028]

As described above, according to the brake system for a multi-axle trailer of the present invention, of the plurality of axles, two followers of the left and right wheels of the axle having the heaviest axle load during braking are provided. A valve that switches from a state in which at least one of the pair of anti-skid control valves is communicated to a state in which only the anti-skid control valve that outputs high pressure communicates based on a difference in output pressure between the pair of anti-skid control valves. Since the device is provided, it is possible to prevent brake drag by increasing the brake release responsiveness at the time of releasing the brake operation while eliminating the lack of braking force on the left and right wheels during the anti-skid control, and improving the entire brake system. This can be simplified as compared with the conventional case.

[Brief description of the drawings]

FIG. 1 is a piping diagram of a brake system for a multi-axle trailer according to an embodiment of the present invention.

FIG. 2 is a piping diagram of a conventional brake system for a multi-axle trailer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Brake system for multi-axle trailer 2 Front axle 2a Front axle right wheel 2b Front axle left wheel 3 Rear axle 3a Rear axle right wheel 3b Rear axle left wheel 4 Pipe line (service line) 5a Wheel speed sensor 5b Wheel speed sensor 6 tube Road (emergency line) 7a Anti-skid control valve 7b Anti-skid control valve 9 Relay emergency valve 12a Brake chamber (follower) 12b Brake chamber (follower) 13a Brake chamber (follower) 13b Brake chamber (follower) 15 Valve device 19 movable body 21a entrance 21b entrance 22a exit 22b exit

Claims (3)

[Claims] 1. A brake system for a multi-axle trailer comprising a plurality of axles arranged in the front-rear direction of a vehicle, each having left and right wheels, wherein a brake pressure is applied to all wheels according to a driver's brake operation. Providing a follower to be supplied, of the plurality of axles, axle lightest axle weight during braking, a pair of sensors for detecting the rotational speed of each of the left and right wheels,
A pair of anti-skid control valves that operate in response to the tendency of the wheels to lock based on the output signals of the pair of sensors and individually adjust the brake pressure supplied to the followers of each of the left and right wheels. In the brake system for an axle trailer, from a state in which at least one of the pair of anti-skid control valves communicates with two followers of left and right wheels of the axle having the heaviest axle load during braking among the plurality of axles, A brake for a multi-axle trailer, comprising: a valve device that switches to a state in which only the anti-skid control valve that outputs a high pressure is communicated based on a difference in output pressure between the pair of anti-skid control valves. system. 2. The valve device is connected to a pair of inlets respectively connected to output ports of the pair of anti-skid control valves, and two followers of left and right wheels of an axle having the heaviest axle load during braking. An outlet, and a body formed with an inner hole communicating the pair of inlets and the outlet, wherein the inner hole moves according to a difference in pressure introduced into the pair of inlets, and the pair of inlets The brake system for a multi-axle trailer according to claim 1, further comprising a movable body that blocks one of the first and second outlets from the outlet and connects the remaining one of the inlets to the outlet. 3. The valve device is connected to a pair of inlets respectively connected to an output port of the pair of anti-skid control valves, and to followers of left and right wheels of an axle having the heaviest axle load during braking. The brake system for a multi-axle trailer according to claim 1 or 2, further comprising a main body having a pair of outlets.