JPH10129461A - Brake controller for tractor and trailer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control the brake of a trailer more appropriately by discriminating respective tendencies of trailer-swing phenomenon and a jack-knife phenomenon more accurately and at a lower cost. SOLUTION: In the case of a trailer-swing tendency, a targeted brake ratio setting and changing means 56 changes the targeted braking ratio of a trailer so as to be small by the output of a relative angular change discriminating means 54, and trailer brake is controlled so that the trailer braking ratio is changed to be a changed targeted braking ratio, and trailer swing preventive control is conducted for braking of a trailer. In the case of a jack-knife tendency, the targeted braking ratio setting and changing means 56 changes the targeted braking ratio of the trailer so as to be large by the output of the relative angular change discriminating means 54, trailer braking is controlled so that the trailer braking ratio is controlled so that the trailer braking ratio may be a changed targeted braking ratio, and jack-knife preventive control is conducted for the braking of the trailer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of brake control of a connected vehicle in which a tractor and a trailer are connected via a coupler, and in particular, uses a coupling force applied to the coupler by pushing up a trailer or the like. In a tractor / trailer brake control that performs a coupling force control (hereinafter also referred to as CFC) for controlling a brake pressure, a tractor / trailer brake control device for preventing a tractor / trailer jackknife phenomenon and a trailer swing phenomenon. It concerns the technical field.

[0002]

2. Description of the Related Art In a tractor / trailer connection vehicle in which a trailer is connected to a tractor via a coupler, an air brake system is generally employed for both the tractor and the trailer. That is, a brake pressure necessary for braking the tractor and the trailer is formed by the air pressure. This brake pressure is preferably adjusted so that the trailer is decelerated with exactly the same braking acceleration as the tractor.

[0003] Therefore, conventionally, a trailer brake control method in which a braking pressure supplied to a trailer in relation to a braking force of a tractor is adjusted to keep the braking force of the trailer constant at an appropriate value each time. However, Japanese Patent Laid-Open
-310111.

The trailer brake control method disclosed in this publication is a brake control method using the above-mentioned CFC. In this case, the coupling force applied to the coupler by trailer thrust or the like is 0 or a slightly negative value, that is, The trailer braking force is set to be slightly greater than the tractor braking force. The reason for setting the brake force of the trailer in this manner is that if the brake force of the trailer is set smaller than the brake force of the tractor, the trailer pushes up against the tractor during braking of the tractor / trailer, causing a so-called jackknife phenomenon. This is because there is a possibility that the jackknife phenomenon may be prevented, and because it is conventionally better to set the braking force of the trailer to be larger than the braking force of the tractor in driving feeling.

In the trailer brake control method disclosed in this publication, a coupling force sensor is used to measure the coupling force applied to the coupler by the trailer. However, since the coupling force sensor is extremely expensive, it has been relatively difficult to commercialize the aforementioned trailer brake control method.

Therefore, a method of calculating the coupling force without using such a coupling force sensor has been proposed in Japanese Patent Laid-Open No. Hei 6-323931. The coupling force calculation method disclosed in this publication defines the balance of the force in the vertical direction (hereinafter, also referred to as the vertical direction in the description of the present invention) and the force in the front-rear direction in the tractor. The coupling force is calculated from the balance between the vertical force and the longitudinal force. According to this coupling force calculation method, it is possible to know the coupling force at low cost without using an expensive coupling force sensor.

[0007]

However, in the trailer brake control method disclosed in the above two publications, the trailer brake force is set to be larger than the tractor brake force, so that the trailer is not used. It tends to be overbrake when it is a little. When the trailer is overbrake, there is a problem that the trailer may run over the tractor, that is, a so-called trailer swing phenomenon may easily occur.

In the coupling force calculation method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. Hei 6-323931, not only the data of the tractor is necessary for the calculation but also these data are detected values, It is a measured value or a constant.

However, the use frequency of the trailer is generally lower than the use frequency of the tractor, and the life of the trailer is long. For this reason, various types of trailers are connected to the tractor from the old model to the new model, and the combination of the tractor and the trailer is not constant. Further, the loading state of the trailer has various states from an empty state to a full state.
Therefore, the trailer under various conditions is connected to the tractor, and it is desirable that the coupling force calculation also takes into account the data of the trailer so that the brake control of the trailer can be performed more accurately.

Further, as described above, since the trailer under various conditions is connected to the tractor, the braking forces required for the tractor brake and the trailer brake are not constant, and depending on the conditions of the trailer, the braking force of the trailer may be insufficient. Or excessive. If the braking force of the trailer becomes excessive, the trailer swing phenomenon is likely to occur, and if the braking force of the trailer is insufficient, the jackknife phenomenon tends to occur, and the running of the tractor / trailer becomes unstable. For this reason, it is desirable to control the tractor and trailer brakes as appropriately as possible.

Incidentally, in order to know the data of the tractor and the trailer, it is necessary to provide various sensors and control devices on the tractor and the trailer. However, installing sensors and control devices on the trailer not only increases the cost, but also makes it extremely economically useless to install them on a trailer that is less frequently used than a tractor. It will be something without. Therefore, there is a demand for more appropriately controlling the tractor and trailer brakes without providing these sensors and control devices on the trailer.

The present invention has been made in view of such circumstances, and has as its object to provide a more accurate and inexpensive trailer swing phenomenon and jackknife phenomenon without providing various sensors and control devices on the trailer. An object of the present invention is to provide a tractor / trailer brake control device capable of judging a tendency and controlling a trailer brake more appropriately.

[0013]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the invention of claim 1 is a brake control device for a tractor and a trailer connected to each other via a coupler, The brake of the trailer is operated and controlled by an air pressure output from a brake valve provided, and a brake ratio of the trailer calculated using at least a coupling force applied to the tractor by the trailer via the coupler is a target brake. A tractor / trailer brake control device that performs brake control so as to achieve a ratio, and a vehicle turning determination unit that determines and outputs whether the tractor is being steered,
When a change in the relative angle between the tractor and the trailer during steering is smaller than a first predetermined value based on an output signal from the vehicle turning determining means, a trailer swing avoidance control signal is output and the relative angle during steering is controlled. And a means for outputting a signal for maintaining the current brake control when the change is not smaller than the first predetermined value.

Further, according to the present invention, the change in the relative angle is not smaller than a first predetermined value during steering, and the change in the relative angle is equal to or larger than a second predetermined value larger than the first predetermined value. , A means for outputting a jackknife avoidance control signal is provided.

Further, the invention according to claim 3 further comprises, based on an output signal from the vehicle turning determining means, that the vehicle is not being steered,
When the change in the relative angle between the tractor and the trailer is larger than the third predetermined value, a jackknife avoidance control signal is output. When the steering is not being performed and the change in the relative angle is not larger than the third predetermined value, And a means for outputting a signal for maintaining the brake control.

The invention according to claim 4 is a brake control device for a tractor and a trailer connected to each other via a coupler, wherein the trailer is controlled by an air pressure output from a brake valve provided on the tractor. Tractor / trailer brake control for controlling the operation of the brake of the tractor and performing brake control such that the brake ratio of the trailer calculated using at least the coupling force applied to the tractor by the trailer via the coupler becomes the target brake ratio. A vehicle turning judgment means for judging whether or not the tractor is being steered and outputting the result, and based on an output signal from the vehicle turning judgment means, not being steered, and between the tractor and the trailer. Outputs the jackknife avoidance control signal when the change in the relative angle is greater than a predetermined value. Together, not being steered, when the change of the relative angle is not greater than the predetermined value, is characterized in that it comprises a means for outputting a signal to maintain the current of the brake control.

Further, the invention of claim 5 is characterized in that the trailer swing avoidance control is executed by lowering the target brake ratio of the trailer and performing a pressure reduction control of the trailer brake.

Further, the invention of claim 6 is characterized in that the jackknife avoidance control is executed by increasing the target brake ratio of the trailer and performing pressure increase control of the trailer brake.

[0019]

In the brake control apparatus according to the first aspect of the present invention, when the relative angle between the tractor and the trailer changes less than a first predetermined value during steering of the tractor / trailer, the trailer swings. If there is a tendency, trailer swing avoidance control is performed.
As a result, the trailer swing phenomenon of the trailer is dealt with at an early stage and is reliably prevented. Therefore, the brake control of the tractor / trailer can be controlled more finely, and the tractor / trailer can run stably and safely.

According to the second aspect of the present invention, when the change in the relative angle is not smaller than the first predetermined value during steering, the change in the relative angle is equal to or larger than a second predetermined value larger than the first predetermined value. At this time, assuming that the tractor / trailer has a tendency to jackknife, jackknife avoidance control is performed. This ensures that the jackknife phenomenon is dealt with at an early stage and is reliably prevented. Accordingly, the tractor / trailer brake control can be more finely controlled.

Further, according to the third and fourth aspects of the invention, when the relative angle between the tractor and the trailer is not larger than the third predetermined value and the steering is not being performed, the tractor / trailer tends to have a jackknife tendency. Similarly, jackknife avoidance control is performed. This ensures that the jackknife phenomenon is dealt with at an early stage and is reliably prevented.

Further, in the invention of claim 5, the trailer swing avoiding control is executed by lowering the target brake ratio of the trailer and performing the pressure reduction control of the trailer brake.

Furthermore, in the invention of claim 6, the jackknife avoidance control is performed by increasing the target brake ratio of the trailer and performing the pressure increase control of the trailer brake.
Be executed.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a tractor according to the present invention.
It is an air brake circuit diagram on the tractor side of the tractor / trailer air brake system used in each of the embodiments of the trailer brake abnormality alarm device and the tractor / trailer brake brake control device.

As shown in FIG. 1, an air brake system 1 on the tractor side includes a brake pedal 2 for performing a brake operation and a dual brake for controlling supply and discharge of a brake operation instruction pressure for a service brake of a tractor / trailer. A brake valve 3, a main reservoir 4 for storing air at a predetermined pressure, and first to fourth sub reservoirs 5, 6, 7, connected to the main reservoir 4 and storing air from the main reservoir 4 at a predetermined pressure. 8, a compressor 9 for supplying air to the main reservoir 4, and another normal circuit when at least one of the circuits of the first to fourth sub reservoirs 5, 6, 7, 8 fails. And a protection valve 10 for protecting the air pressure of the vehicle and brakes applied to the left and right front wheels by supplying air from the first sub-reservoir 5, respectively. Left and right front wheel power chambers 11, 12 for generating a braking force for kicking the left and right front wheel power chambers 11, 12 by the brake actuation command pressure by the air of the first Saburizaba 5 from the brake valve 3
Front wheel relay valve 13 for controlling air supply and exhaust to and from
Anti-lock (hereinafter also referred to as ABS) modulators 14 and 15 for adjusting air pressures supplied to the left and right front wheel power chambers 11 and 12 to prevent locking of the left and right front wheels, respectively; Left and right rear wheel spring brake actuators 16 and 17 with spring brakes for generating a braking force for applying a brake to the left and right rear wheels by supplying air from the second sub-reservoir 6 to the left and right rear wheels, respectively. A rear-wheel relay valve 18 for controlling the supply and exhaust of air to and from the brake actuators 16 and 17, and a rear-wheel relay valve 18 without the brake valve 3
An electromagnetic proportional valve 19 for supplying a brake operation instruction pressure proportional to an input signal of the second sub-reservoir 6 by air, and a brake operation instruction pressure by the air of the second sub-reservoir 6 from the normal brake valve 3 to a rear wheel relay valve. 18 for controlling the operation of the first switching valve 20 for supplying the brake operation command pressure from the electromagnetic proportional valve 19 to the rear wheel relay valve 18 when necessary. A first electromagnetic switching valve 21 for controlling the supply of pilot pressure by air of the second sub-reservoir 6 to the first switching valve 20
And an ABS modulator 22, which adjusts the air pressure supplied to the left and right rear wheel spring brake actuators 16, 17 to prevent the left and right rear wheels from being locked.
23, and controls the tractor and trailer emergency brakes and parking brakes by controlling the spring brake actuator release command pressures for the spring brakes of the left and right rear wheel spring brakes 16 and 17 and manually controlling the trailer brakes. The right and left rear wheel spring brake actuators 16 and 1 are operated by a hand control valve 24 and a spring brake operation release instruction pressure from the hand control valve 24.
7, a spring brake relay valve 25 for controlling the supply and exhaust of air from the third sub-reservoir 7 to the spring brake of No. 7, and supply and control of air from the third sub-reservoir 7 to the trailer service line A to operate the trailer brake. The air is branched from an air passage 27 between the hand brake valve 26 and the hand brake valve 26 and the third sub reservoir 7, and supplies the air from the third sub reservoir 7 to the trailer service line A to operate the trailer brake. Air passage 28, a second electromagnetic proportional valve 29 disposed in the branch air passage 28 for supplying air pressure proportional to an input signal, and an air pressure output from the second electromagnetic proportional valve 29 when necessary. The second electromagnetic switching valve 30 that supplies the trailer service line A and the air from the hand brake valve 26 Check valve 31 that outputs the larger of the pressure and the air pressure from the second electromagnetic switching valve 30, and the output pressure from the brake valve 3 and the double check valve 31 for the service brake of the trailer. The air having the larger output pressure is selected and supplied to the trailer service line A, and the air from the hand control valve 24 is supplied to the trailer service line A for the parking brake of the trailer.
Supply air from sub reservoir 7 to trailer supply line B
To the passage 33 connecting the first outlet D1 of the brake valve 3 and the first designated pressure port C1 of the trailer control valve 32 to the front wheel relay valve 13 The second trailer control valve 32
A switching valve 34 and a first pressure pickup 35 for detecting the air pressure from the brake valve 3 to detect the brake operation
A second pressure pickup 36 for detecting an air pressure output from the second electromagnetic switching valve 30; and a third pressure pickup 37 for detecting an air pressure output from the rear wheel relay valve 18.
A steering angle sensor 51 for detecting a steering angle of a steering wheel, and a relative angle sensor 52 for detecting a relative angle of a tractor / trailer.
And first to third pressure pickups 35, 36, 37, ABS modulators 14, 15, 22, 23 for front, rear, left and right wheels,
First and second electromagnetic proportional valves 19, 29, first and second
An electronic control unit (hereinafter, referred to as an electronic control unit) to which the electromagnetic switching valves 20, 30, the steering angle sensor 51, and the relative angle sensor 52 are connected.
ECU 38), a tractor-side coupler 39 for the trailer service line A, and a tractor-side coupler 40 for the trailer supply line B.

The trailer control valve 32 selects the larger one of the indicated pressure of the first indicated pressure port C1 and the indicated pressure of the second indicated pressure port C2, and sets the pressure corresponding to the selected indicated pressure to the first indicated pressure. Output from exit D1.

The tractor air brake system 1 includes an ABS system that adjusts the brake pressure of the wheels so that the wheels are unlocked when the wheels are locked, and a brake applied to the drive wheels so that the idles are canceled when the drive wheels idle. A traction control (hereinafter also referred to as a TRC system) is provided. Therefore, although not shown, a wheel speed sensor for detecting the wheel speed is provided on the wheel of the tractor.

FIG. 2 is an air brake circuit diagram on the trailer side of the tractor / trailer air brake system shown in FIG. As shown in FIG. 2, the trailer-side air brake system 41 includes a trailer reservoir 42 for storing air for a trailer service brake at a predetermined pressure, and air supplied from the trailer reservoir 42 to supply the left and right front wheels. The left and right front wheel power chambers 43 and 44, which generate braking force for applying the brake, and the left and right rear wheel generating brake force for applying the brake to the rear left and right wheels, respectively, by supplying air from the trailer reservoir 42. Trailer service line A from rear wheel power chambers 45 and 46, tractor side brake valve 3
Connected to the trailer relay valve 47 and the tractor-side coupler 39 for the trailer service line A for controlling the supply and exhaust of air to the left and right front and rear wheel power chambers 43, 44, 45 and 46 by the brake operation instruction pressure supplied through Trailer side coupler 4 for trailer service line A
8. Tractor-side coupler 4 for trailer supply line B
A trailer-side coupler 49 for the trailer supply line B connected to the trailer supply line B is provided.

In the tractor / trailer air brake system configured as described above, when the trailer is connected to the tractor, the trailer-side coupler 48 of the trailer service line A is connected to the tractor-side coupler 39 of the trailer service line A. At the same time, the trailer-side coupler 49 of the trailer supply line B is connected to the tractor-side coupler 40 of the trailer supply line B. When the hand control valve 24 is set to the parking brake release position I, the spring brake operation release instruction pressure is supplied to the spring brake relay valve 25, and the air in the third sub reservoir 7 is released from the spring brake relay valve 25 and the double Check valve 50
Through each spring brake actuator 16,1
7 are supplied to the spring brake release chambers 16a and 17a. Thereby, the spring brake of the tractor is released, and the parking brake is released.

Further, since the trailer parking brake operation release command pressure from the hand control valve 24 is supplied to the trailer control valve 32, the trailer control valve 32 is operated by the power chambers 43, 44, 45, 46 for the right, left, front and rear wheels of the trailer. The air inside is exhausted and the parking brake of the trailer is released.

In this state, the tractor / trailer runs,
When the brake pedal 2 is depressed to apply the service brake during the traveling, the brake valve 3 is switched, and the first and second inlets S1 and S2 are connected to the corresponding first and second outlets D1 and D2, respectively. You. This allows
The air of the first sub-reservoir 5 has a first inlet S1 and a first outlet
It is supplied as a brake operation instruction pressure to an instruction pressure port C of the front and rear wheel relay valve 13 through D1. Therefore, the inlet S and the outlet D of the relay valve 13 communicate with each other, and the first sub-reservoir 5 which is supplied to the inlet S of the relay valve 13 is connected.
Is supplied to the left and right front wheel power chambers 11 and 12 through the outlet D and the ABS modulators 14 and 15, and the service brakes of the left and right front wheels of the tractor are applied, respectively.

The air in the second sub-reservoir 6 is output from the second outlet D2 of the brake valve 3. At this time, the air pressure from the second outlet D2 is detected by the first pressure pickup 35, and a brake operation detection signal is sent to the ECU 38. The ECU 38 performs brake control by CFC using a coupling force described later. That is,
The ECU 38 calculates the braking force required for the tractor based on the coupling force,
The first electromagnetic proportional valve 19 is controlled based on the calculation result. In this case, the coupling force corresponds to the axle load of the trailer. As a result, the first electromagnetic proportional valve 19 outputs an air pressure corresponding to the braking force calculated by controlling the air pressure of the second sub reservoir 6. Further E
The CU 38 switches the first electromagnetic switching valve 21 to the position II,
Thereby, the first switching valve 20 is switched. Therefore, the indication pressure port C of the relay valve 18 is connected to the output side of the first electromagnetic proportional valve, and the air of the air pressure output from the first electromagnetic proportional valve 19 is supplied to the indication pressure port C of the relay valve 18.
For this reason, the inlet S and the outlet D of the relay valve 18 communicate with each other, and the air of the second sub-reservoir 6 supplied to the inlet S of the relay valve 18 passes through the outlet D, the ABS modulators 22 and 23, and then flows right and left. Service brake chamber 16b, 1 of wheel spring brake actuator 16,17
7b, and the service brakes of the left and right rear wheels of the tractor are respectively applied. In this case, the left and right rear wheel spring brake actuators 16 and 17 brake the rear wheels of the tractor with a braking force corresponding to the coupling force.

When the first electromagnetic proportional valve 19, the first electromagnetic switching valve 21, or the first pressure pickup 35 fails, air from the second outlet D2 of the brake valve 3 passes through the switching valve 20 and passes through the relay valve. Since the pressure is supplied to the designated pressure port C of 18, the service brake of the rear wheel of the tractor can be reliably applied.

On the other hand, the ECU 38 calculates the braking force required for the trailer based on the coupling force, and controls the second proportional solenoid valve 29 based on the calculation result. In this case, the coupling force corresponds to the axle load of the trailer. As a result, the second electromagnetic proportional valve 29 outputs an air pressure according to the braking force calculated by controlling the air pressure of the third sub reservoir 7. Further, the ECU 38 switches the second solenoid-operated directional control valve 30 to the position II, and supplies the air of the air pressure output from the second solenoid-operated proportional valve 29 to
It is supplied to the second indication pressure port C2 of the trailer control valve 32 through the double check valve 31. At this time,
Since the air pressure supplied to the second instruction pressure port C2 of the trailer control valve 32 is introduced into the second switching valve 34, the second switching valve 34 is switched to the second position II and the first switching valve 34 is switched to the first position II. The indication pressure port C1 is communicated with the atmosphere.

For this reason, at the time of normal brake operation, the air pressure of the second designated pressure port C2 becomes larger than that of the first designated pressure port C1, and the trailer control valve 32 sets the air pressure of the second designated pressure port C2, ie, Air having a pressure corresponding to the air pressure according to the axle load of the trailer controlled by the second electromagnetic proportional valve 29 is always supplied to the designated pressure port C of the trailer relay valve 45. As a result, the output pressure of the trailer relay valve 45 always becomes the air pressure according to the axle load of the trailer, and the air of this air pressure is supplied to each power chamber 4 of the trailer.
3, 44, 45, and 46, and the service brakes of the left, right, front, and rear wheels of the trailer are applied.

Therefore, during normal brake operation, the brake of the trailer always has an appropriate braking force according to the loaded weight. Even when the air pressure controlled by the second electromagnetic proportional valve 29 is smaller than the air pressure from the brake valve 3, the trailer control valve 32 generates air having a pressure corresponding to the air pressure controlled by the second electromagnetic proportional valve 29. Since the air is supplied to the trailer relay valve 45, the braking force of the trailer does not become excessively large unlike the conventional air brake system.

As described above, when the normal brake is applied,
The trailer does not under brake or over brake, and the occurrence of the jackknife phenomenon and the swing phenomenon is suppressed. Further, the ECU 38 turns on a stop lamp (not shown) in response to a brake operation signal from the first pressure pickup 35 to display a brake operation to notify a following vehicle.

When the brake pedal 2 is released to release the service brake, each of the outlets D1, D2 of the brake valve 3 is released.
Is shut off from each of the inlets S1 and S2 and connected to the exhaust port E, so that the indication pressure port C of the front wheel relay valve 13 on the tractor side is set.
Is exhausted from the exhaust port E of the brake valve 3. For this reason, the relay valve 13 is deactivated and its outlet D is cut off from the inlet S and connected to the exhaust port E, so that the air supplied to the power chambers 11 and 12 is discharged from the exhaust port E of the relay valve 13. Exhausted from
The service brake on the front wheel of the tractor is released. Also,
Air supplied to the command pressure port C of the rear wheel relay valve 18 on the tractor side is exhausted from the exhaust port E of the brake valve 3. As a result, the relay valve 18 is deactivated and its outlet D is cut off from the inlet S and connected to the exhaust port E, so that the spring brake actuators 16, 1 are connected.
7 is supplied to the exhaust port E of the relay valve 18.
And the service brake on the rear wheel of the tractor is released.

Further, since there is no brake operation signal from the first pressure pickup 35, the ECU 38 switches the second electromagnetic switching valve 30 to the original position I. As a result, the air supplied to the second instruction pressure port C2 of the trailer control valve 32 is exhausted into the atmosphere from the second electromagnetic switching valve 30, so that the air supplied to the trailer service line A is reduced to the trailer control valve. Air is exhausted from the 32 exhaust ports E. Therefore, the trailer relay valve 45
Is shut off from the inlet S and connected to the exhaust port E, so that air supplied to the power chambers 43, 44, 45, and 46 is exhausted from the exhaust port E of the trailer relay valve 47, and The service brake of each wheel is released.

When the ECU 38 detects a lock on the tractor wheel based on a wheel speed signal from a wheel speed sensor (not shown) disposed on each wheel of the tractor, the ECU 38 modulates the ABS modulator of the locked wheel. 14,1
The air pressure of the power chambers 11 and 12 or the brake actuators 16 and 17 is adjusted so as to release the wheel lock by controlling 5, 22, and 23. Further, when the ECU 38 detects the idling of the drive wheels of the tractor based on the wheel speed signals from the wheel speed sensors of the drive wheels of the tractor, the ECU 38 operates the first electromagnetic proportional valve 19 and the first electromagnetic switching valve 21 to operate the brake actuator. Air pressure is supplied to the driving wheels 16 and 17, and the driving wheels are braked so that the idling of the driving wheels is eliminated.

The tractor / trailer air brake system
In the stem, as shown in FIG.
Each axis A of₁, A_Two, A_Three, A_FourBrake Ratio Z₁,
Z_Two, Z_Three, Z_FourThe trailer brake so that
Is controlling. These brake ratios Z₁, Z_Two, Z_Three,
Z_FourIs the braking force F of each wheel₁, F_Two, F_Three, F_FourThe axle load
W ₁, W_Two, W_Three, W_FourDefined by dividing by. This
Brake ratio Z of each axis₁, Z_Two, Z_Three, Z_FourMake the same
To maximize the rate of road surface adhesion.
And regardless of the trailer load weight,
The effect of the key is kept constant.

Next, a specific example of a trailer brake control method in which the brake ratios Z ₁ , Z ₂ , Z ₃ , and Z _{4 of} the tractor and trailer axes are the same will be described.

As one example, the brake ratio Z ₁ of the tractor front axis A ₁ is set as the target brake ratio, and the brake ratio Z ₂ , Z of the tractor rear axis A ₂ and each of the trailer axes A ₃ , A ₄ are set. _3, Z ₄ controls the braking force and the braking force of the trailer of a tractor rear axle a ₂ to be the same as the target braking ratio. In that case, the load of the tractor front axle A ₁ as described above to be constant. The vertical component F _kz of the coupling force F _k is almost applied to the rear axis A ₂ ,
Since the front axle A ₁ load is almost the same as that at the time the tractor motorcycle, as well thus the load of the tractor front axle A ₁ constant, no particular trouble.

The ECU38 is to calculate the coupling force F _k and brake ratio Z will be described later,
These coupling force F _k and brake ratios Z, the brake ratio of the tractor rear axle A ₂ and each axis of the trailer _{A 3, A 4 Z 2,} Z 3, Z 4 is the target brake ratio tractor front axle A ₁ of the braking force of the brake ratio Z ₁ is the same as the above tractor rear axle a ₂ and calculates the braking force of the trailer. Then, the ECU 38 switches the electromagnetic switching valves 21 and 30 and controls the electromagnetic proportional valves 19 and 29 to control the rear shaft brake of the tractor and the brake of the trailer to the respective calculated braking forces. In this case, when the brake ratio of a certain axis is smaller than the target brake ratio, the brake pressure of that axis is increased to increase the braking force, and when the brake ratio is larger than the target brake ratio, Brake control is performed so that the brake pressure is reduced and the braking force is reduced. Thereby, the brake ratio of the axis is corrected so as to be the same as the target brake ratio.

As a second example, the brake ratios Z ₃ and Z ₄ of the semi-trailer have coupling force ratios F _kx
Use that can be assumed to be approximately equal to / F _kz . That is, in the second example, the coupling force ratio F _kx / F _kz and the brake ratio Z ₂ of the tractor rear shaft A ₂ are the same as the brake ratio Z ₁ of the tractor front shaft A ₁ which is the target brake ratio. braking force of the tractor rear axle a ₂ and controls the braking force of the trailer. In this case, the load of the tractor front axle A ₁ is constant. And
If the brake ratio is different from the target brake ratio,
The same brake control as in the above example is performed, and the brake ratio is corrected so as to be the same as the target brake ratio.

Further, as a third example, the brake force of the trailer is controlled such that the trailer brake ratios Z ₃ and Z ₄ have a predetermined value set as a target brake ratio. As the specified value, for example, the relationship between the brake pressure _Pm and the brake ratio Z shown in FIG. 11 is used. Also in this example, when the brake ratio is different from the target brake ratio, the correction is made to be the same as in the above-described respective examples.

Further, as a fourth example, the brake force of the trailer is controlled so that the trailer brake ratios Z ₃ and Z ₄ become the brake ratio Z ₁ of the front axis A ₁ of the tractor which is the target brake ratio. Also in this example, when the brake ratio is different from the target brake ratio, the correction is made to be the same as in the above-described respective examples.

Further, as a fifth example, the brake force of the trailer is controlled such that the coupling force ratio F _kx / F _kz becomes a specified value preset as a target brake ratio. As the specified value, for example, the relationship between the brake pressure _Pm and the brake ratio Z shown in FIG. 11 is used. Also in this example, when the brake ratio is different from the target brake ratio, the correction is made to be the same as in the above-described respective examples.

Further, as a sixth example, the brake force of the trailer is controlled so that the coupling force ratio F _kx / F _kz becomes the brake ratio Z ₁ of the front axis A ₁ of the tractor which is the target brake ratio. Also in this example, when the brake ratio is different from the target brake ratio, the correction is made to be the same as in the above-described respective examples.

By the way, in order to perform the trailer brake control method using the CFC, it is necessary to obtain the coupling force F _k , the coupling force ratio F _kx / F _kz and the brake ratio Z. Ring force F _k , coupling force ratio F _kx
A method for determining / F _kz and the brake ratio Z will be described. In this case, as a prerequisite, (1) As shown in FIG. 1, an ABS / TRC is provided in the tractor brake system. Therefore, each wheel of the tractor is provided with a wheel speed sensor, and the vehicle acceleration is reduced. (2) The rear wheel of the tractor is supported by an air suspension, (3) The weight of the tractor alone, the axle load of the tractor, and various data on the dimensions of the tractor are known and constant. There are certain things to set.

First, the coupling force will be described. In the present invention, the coupling force is estimated using the data of the tractor and the trailer without using an expensive coupling force sensor.
The data required to estimate the coupling force are: (a) Data on the tractor: mass , (rear axle load), weight
Coupler position and axle position with respect to the center; (b) data on the trailer: mass, coupler position and axle position with respect to the center of gravity, and (c) (vehicle acceleration), of which the underlined data is known and constant. Yes, and the data in parentheses is measurable data. Therefore, it suffices to obtain the data relating to the trailer in (b). In this case, no sensor or control device for obtaining the trailer data is provided on the trailer, and the data of these trailers is also estimated.

Table 1 shows specific data for estimating the coupling force.

[0053]

[Table 1]

FIG. 4 is a diagram for explaining an example of a method for estimating the coupling force. As shown in FIG. 4, first to estimate the trailer mass M _a. Data required for calculating the trailer mass M _a, the engine driving force (engine torque)
F _m , vehicle acceleration a and tractor mass M _z . Engine drive force F _m is the engine speed, it can be estimated from the governor angle and engine torque map. Further, the vehicle acceleration a can be obtained from a wheel speed signal from a wheel speed sensor. Then, the ECU 8 calculates the formula F _m = (M _z + M _a )
× calculates the mass M _a trailer from a. This allows
Trailer mass M _a can be estimated, this estimation of the trailer mass M _a is performed for each time of acceleration, is stored in the memory.

Next, the coupler position and the axle position with respect to the center of gravity of the trailer are estimated. The trailer center of gravity in FIGS. 4, 7, 9, and 10 hereinafter means the coupler position and the axle position with respect to the center of gravity of the trailer. In FIGS. 4 to 7 and 9, the term "center of gravity of the tractor" means the position of the coupler and the axle relative to the position of the center of gravity of the tractor.

The estimation of each of these positions is performed based on a formula for balancing forces in the front-rear direction and the vertical direction and a formula for balancing forces at the center of gravity. First, to estimate the coupler position X _ak and the axle position X _a relative longitudinal direction center of gravity of the trailer. Therefore, when the vehicle is stopped first, estimating the tractor rear axle load F ₂ by the air suspension pressures of the tractor. The trailer axle load F ₂ , the estimated trailer mass M _a , the known tractor mass M _z , the known coupler position X _k and the known axle position X ₁ with respect to the center of gravity of the tractor, Of the coupler position X _ak and the axle position X _a with respect to the center of gravity in the front-rear direction.

Next, estimate the coupler position Z _ak and the axle position Z _a relative vertical position of the center of gravity of the trailer. Therefore, when the first acceleration, with estimates the tractor rear axle load F ₂ by the air suspension pressures of the tractor, estimates the vehicle acceleration a by the wheel speed sensor. Then, this tractor rear axle load F _2, the trailer mass M _a and a mass M _z of known tractors, known coupler position Z _k and the known axle position relative to the center of gravity of the tractor Z ₁₂ described above estimated
If, from a vehicle acceleration a described above estimation, it estimates the coupler position Z _ak and the axle position Z _a relative position of the center of gravity of the vertical trailer. Estimation of the coupler position Z _ak and the axle position Z _a relative vertical position of the center of gravity of the trailer is carried out every time the vehicle acceleration, stored in the memory.

Next, to estimate the coupling force F _k of the front and rear direction and the vertical direction at the time of braking. Estimation of the coupling force F _k is so with the estimation result of each data described above is carried out from the balance equation of the moment of force at the balance equation and the center of gravity of the longitudinal and vertical forces. Specifically, the front-rear component F _kx and the vertical component F _kz of the coupling force are calculated using the following equations 1 and 2 (equation 25 described on page 10 of JP-A-6-323931). .

[0059]

(Equation 1)

[0060]

(Equation 2)

In this way, the coupling force F _k is estimated by the coupling force estimation method of this example.

FIG. 5 is a diagram for explaining another example of the coupling force estimation method. As shown in FIG. 5, in the coupling force estimation method of this example, first, a coupling force ratio F _kx / F _kz is calculated.

The data required for calculating the coupling force ratio F _kx / F _kz includes the braking force F _a , the vehicle acceleration a, the tractor mass M _z , and the coupler position X _k with respect to the tractor center of gravity position,
Z _k and the axle position _{X 1, X 2, Z 12} , and a tractor rear axle load F _2. The braking force _Fa is the third pressure pickup 37
Can be estimated from the brake pressure sensor detected by The vehicle acceleration a can be obtained from the wheel speed sensor in the same manner as described above. Furthermore, the tractor rear axle load F ₂ can be estimated from in the same way as described above the air suspension pressure. Other data are known quantities.

Then, the ECU 8 calculates the following Equation 3 (Equation 2 described on page 9 of Japanese Patent Laid-Open No. Hei 6-323931).
The coupling force ratio F _kx / F _kz is calculated using 3).

[0065]

(Equation 3)

On the other hand, the vertical component F _{kz of the} coupling force F _k is obtained by subtracting the rear axle load of the tractor alone (when the semitrailer is not connected) from the tractor rear axle load F _2.
Is calculated. The calculation of the vertical component F _kz of the coupling force F _k is based on the tractor mass M _z , the coupler position X _k , Z _k and the axle position X ₁ , X ₂ , Z with respect to the tractor center of gravity position.
It can also be calculated from ₁₂ .

[0067] Then, the vertical component of the coupling force F _k by the vertical component F _kz last coupling force ratio was calculated F _kx / F _kz coupling force F _k F
Calculate _kx . Thus, the coupling force F _k is estimated by the coupling force estimation method of this example.

FIG. 6 is a view for explaining still another example of the method for estimating the coupling force. As shown in FIG.
In the coupling force estimation method of this example, first, a coupling force ratio F _kx / F _kz is calculated. In that case, in the example of the coupling force estimating method of FIG. 5 described above, although including data tractor rear axle load F _2, not included in the tractor rear axle load F ₂ in the example of this coupling force estimating method , Braking force F _a , vehicle acceleration a, tractor mass M _z , coupler position X _k , Z _k and axle position X ₁ , X ₂ , Z _{12 with} respect to the tractor center of gravity position,
(Equation 21 described on page 9 of JP-A-6-323931) using the coupling force ratio F _kx / F
Calculate _kz .

[0069]

(Equation 4)

Thereafter, the vertical component F _kz and the vertical component F _kx of the coupling force F _k are calculated in the same manner as in the above-described example of the coupling force estimation method shown in FIG. Thus, the coupling force F _k in the coupling force estimation method of this example is estimated.

FIG. 7 is a diagram for explaining an example of a method of calculating the brake ratio. As shown in FIG. 7, the brake ratio calculation method of this example first calculates the braking force of the tractor and the trailer during braking. The braking force F _a tractor calculated from similarly brake pressure in the case shown in FIGS. 5 and 6, the braking force of the trailer, the braking force F _a of this tractor,
The vehicle deceleration a estimated by the wheel speed sensor, the tractor mass M _z , the trailer mass and the coupling force F of FIG. 4 calculated by an example of the coupling force calculation method.
Calculated from _k data.

Next, the front-axis braking force and the rear-axis braking force of the tractor are calculated based on the calculated tractor braking force, coupling force _Fk, and coupler position X _k ,
Z _k and the axle position X _1, X _2, respectively calculated from Z _12. The front shaft braking force and the rear shaft braking force of the tractor may be obtained by distributing them at a fixed ratio. Since the braking force distribution ratio of the tractor hardly changes, there is no problem even if the distribution ratio is fixed. Further, the front-axis braking force and the rear-axis braking force of the tractor can be obtained from each output pressure of the brake valve 3.

Next, the trailer shaft load is calculated from the trailer mass obtained in FIG. 4, the coupler position X _ak , Z _ak and the axle position X _a , Z _a with respect to the center of gravity of the trailer. Further, the tractor rear shaft load F _{2 is determined} by the air suspension pressure.
From the rear tractor rear shaft load F ₂ , the tractor mass M _z , the coupling force F _k , and the coupler positions X _k , Z _k and the axle positions X ₁ , X ₂ , Z _{12 with} respect to the tractor center of gravity position. calculates the axial load F _1. Since the vertical component F _kz of the coupling force F _k is almost applied to the rear shaft, the tractor front shaft load F ₁ may be a known constant.

Finally, the tractor braking force, the trailer braking force, the braking force of the front and rear axles of the tractor, the trailer shaft load, and the loads of the tractor front and rear axles are:
The brake ratio of each axis of the tractor and trailer is calculated from the formula (braking force / axial load).

FIG. 8 is a diagram for explaining another example of the method of calculating the brake ratio. As shown in FIG. 8, the braking force of the tractor is calculated from the brake pressure during braking. In this case, the braking force of the tractor is distributed to the front shaft and the rear shaft in the same manner as in the above-described example shown in FIG. 7 to calculate the front shaft braking force and the rear shaft braking force of the tractor. Moreover, to calculate the tractor rear axle load F ₂ from the air suspension pressure. Further, in the case of this embodiment has a tractor front axle load F ₁ and known constant. Then, the brake ratios Z ₁ , Z ₂ of the front shaft and the rear shaft of the tractor are respectively determined by the front shaft braking force and the rear shaft braking force of the tractor, the tractor rear shaft load F ₂ , and the tractor front shaft load F _1. calculate.

On the other hand, in the brake ratio calculating method of this example, the coupling force ratio F _kx shown in FIG. 5 or FIG.
/ F _kz is the trailer brake ratio Z ₃ , Z ₄ .

In this manner, the tractor and the tractor brake ratio Z ₁ ,
Z ₂ , Z ₃ and Z ₄ are obtained.

FIG. 9 is a view for explaining still another example of a method of calculating the brake ratio. As shown in FIG. 9, in the brake ratio calculation method of this example, the coupler position X _ak with respect to the trailer mass M _a , the coupling force F _k , and the center of gravity of the trailer is different from the brake ratio calculation method of the example shown in FIG. Instead of Z _ak and axle position X _a , Z _a , the coupler position X _ak , Z _ak and axle position X _a , Z _{a with} respect to the trailer mass M _a , the coupling force F _k , and the center of gravity of the trailer determined in FIG. Is used to calculate the trailer braking force, the trailer shaft load, and the tractor front shaft load. The other configuration of the brake ratio calculation method of this example is the same as the brake ratio calculation method of the example shown in FIG.

Thus, the tractor and the tractor brake ratio are obtained by the brake ratio calculation method of this example.

FIG. 10 is a diagram for explaining still another example of the method of calculating the brake ratio. As shown in FIG. 10, in the brake ratio calculating method of this example, the trailer braking force calculated by the brake ratio calculating method of the example shown in FIG. 7 and the trailer calculated by the brake ratio calculating method of the example shown in FIG. Only the brake ratio of the trailer is calculated based on the shaft load.

The tractor / trailer brake control device of the present invention is intended to more reliably prevent the tractor / trailer jackknife phenomenon and the trailer swing phenomenon in the tractor / trailer brake control by the CFC as described above. The following brake control is performed.

FIG. 12 is a diagram showing an example of an embodiment of a brake control device for a tractor / trailer according to the present invention.
As shown in FIG. 12, the brake control device of the tractor / trailer of this example determines whether or not steering is being performed based on a steering angle detection signal from a steering angle sensor 51 provided in the ECU 38. And a tractor / trailer relative angle detection signal from the relative angle sensor 52 to determine whether or not the change in the relative angle is greater than a predetermined value. A relative angle change determining means 54 for generating an output signal based on the output signal from the engine 53, a brake ratio calculating means 55 for calculating at least a brake ratio of a tractor and a trailer using a coupling force, and at least a target brake ratio of the trailer. And a target brake ratio setting / change means 56 for setting and changing.

In the brake control apparatus of the present embodiment thus configured, when the trailer swing tendency is found during the brake control by the CFC, the relative angle change determining means 54
Means for setting and changing the target brake ratio by the output signal of
6 changes the target brake ratio of the trailer to a value smaller than the current value. Therefore, the ECU 38 outputs a trailer brake control signal so that the trailer brake ratio becomes the changed target brake ratio, thereby performing trailer swing avoidance control on the trailer brake. Further, when a tendency toward a jackknife occurs during the brake control by the CFC, the relative angle change determining means
Means for setting and changing the target brake ratio by the output signal of
6 changes the trailer target brake ratio to a value greater than the current value. Therefore, the ECU 38 outputs the control signal of the trailer brake so that the trailer brake ratio becomes the changed target brake ratio, thereby performing the jackknife avoidance control for the brake of the trailer.

More specifically, the brake control is performed according to the flow shown in FIG. That is, first, in step S1, it is determined whether or not the tractor / trailer is being steered. If it is determined that the steering is being performed, it is determined in step S2 whether the relative angle change of the tractor / trailer is smaller than a predetermined value (corresponding to the first predetermined value of the first aspect of the present invention). If it is determined that the change in the relative angle is smaller than the predetermined value, it is determined that the trailer is in a trailer swing phenomenon, and trailer swing avoidance control is performed in step 3. Specifically, the trailer swing avoidance control is executed by lowering the trailer target brake ratio set as described above in the brake control by the CFC and performing the pressure reduction control of the trailer brake. As a result, the trailer swing phenomenon of the trailer is dealt with at an early stage and is reliably prevented.

If it is determined in step S2 that the relative angle change is not smaller than the predetermined value, it is determined that the trailer does not tend to cause a trailer swing phenomenon, and the brake control by the CFC currently performed in step S4 is maintained. Run. If it is determined in step S1 that the tractor / trailer is not being steered, the relative angle change of the tractor / trailer is changed to a predetermined value in step S5 (the third predetermined value of the third aspect of the invention and the predetermined value of the fourth aspect). Is determined. In that case,
This predetermined value may be set to the same value as the predetermined value in step S2, or may be set to a different value. If it is determined that the relative angle change is larger than the predetermined value, it is determined that the tractor / trailer has a tendency to the jackknife phenomenon, and the jackknife avoidance control is performed in step S6. Specifically, the jackknife avoidance control is executed by increasing the target brake ratio of the trailer set as described above in the brake control by CFC and performing the pressure increase control of the trailer brake. This ensures that the jackknife phenomenon of the tractor / trailer is dealt with at an early stage and is reliably prevented.

If it is determined in step S5 that the relative angle change is not larger than the predetermined value, it is determined that the tractor / trailer does not tend to cause the jackknife phenomenon and step S4 is performed.
Then, the brake control by the current CFC is performed.

As described above, according to the brake control device of the present embodiment, the trailer swing phenomenon and the jackknife phenomenon of the tractor / trailer can be reliably prevented, so that the brake control of the tractor / trailer by the CFC can be more finely controlled.・ Stable and safe running of the trailer becomes possible.

According to the brake control device of this embodiment,
Since the brake control by the CFC is performed based on the calculated coupling force and brake ratio, an expensive coupling force sensor becomes unnecessary, and the abnormality alarm device and the brake control device can be formed at lower cost.

FIG. 14 is a diagram showing a flow of brake control in another example of the embodiment of the present invention. In the example shown in FIG. 13 described above, when the relative angle change is not smaller than the predetermined value in step S2, the brake control by the current CFC is performed in step S4. However, in the brake control of this example, As shown in FIG. 14, when the relative angle change is not smaller than the predetermined value in step S2, it is determined in step S7 whether the relative angle change is larger than a second predetermined value. This second predetermined value is set larger than the predetermined value in step S2. If it is determined that the relative angle change is larger than the second predetermined value, it is determined that the tractor / trailer has a tendency to the jackknife phenomenon, and the jackknife avoidance control in step S6 is performed. Thus, even when the tractor / trailer is being steered, if the tractor / trailer tends to have a jackknife phenomenon, this jackknife phenomenon is dealt with at an early stage and is reliably prevented. If it is determined in step S7 that the relative angle change is not larger than the second predetermined value, the current C
The brake control by FC is performed.

As described above, according to the brake control device of this embodiment, the jackknife phenomenon can be reliably prevented even during the steering of the tractor / trailer, so that the brake control of the tractor / trailer by the CFC can be performed more finely than that of the example of FIG. Be able to control. Other configurations, operations, and effects of the brake control device of the present example are the same as those of the above-described brake control device.

[0091]

As apparent from the above description, according to the brake control device of the present invention, the trailer swing phenomenon and the jackknife phenomenon of the tractor / trailer can be reliably prevented at the initial stage thereof. The brake control of the tractor / trailer can be controlled more finely, and the tractor / trailer can run stably and safely.

According to the brake control device of the present invention, since the brake control is performed based on the calculated brake ratio, no sensor or control device is required on the trailer side. Can be formed.

[Brief description of the drawings]

FIG. 1 is an air brake circuit diagram on the tractor side of a tractor / trailer air brake system used in embodiments of a tractor / trailer brake abnormality alarm device and a brake control device according to the present invention.

FIG. 2 is an air brake circuit diagram on the trailer side of the tractor / trailer air brake system shown in FIG.

FIG. 3 is a diagram illustrating a brake ratio and a coupling force in a tractor and a trailer.

FIG. 4 is a diagram illustrating an example of a coupling force estimation method.

FIG. 5 is a diagram illustrating another example of a coupling force estimation method.

FIG. 6 is a diagram showing still another example of the coupling force estimation method.

FIG. 7 is a diagram illustrating an example of a brake ratio estimating method.

FIG. 8 is a diagram showing another example of a brake ratio estimating method.

FIG. 9 is a diagram showing still another example of the brake ratio estimating method.

FIG. 10 is a diagram showing still another example of the brake ratio estimating method.

FIG. 11 is a diagram showing a relationship between a brake pressure and a brake ratio.

FIG. 12 is a diagram illustrating an example of an embodiment of a brake control device for a tractor / trailer according to the present invention.

13 is a diagram showing an example of a flow for performing brake control using the brake control device of the example of FIG.

14 is a diagram showing another example of a flow for performing brake control using the brake control device of the example of FIG.

[Explanation of symbols]

DESCRIPTION OF REFERENCE NUMERALS 1: air brake system on tractor side, 2: brake pedal, 3: dual brake valve, 11, 12: power chamber for left and right front wheels, 13: relay valve for front wheels,
14, 15 ... ABS modulator, 16, 17 ... left and right rear wheel spring brake actuator, 19 ... 1st proportional solenoid valve, 20 ... 1st switching valve, 21 ... 1st solenoid switching valve,
29: second electromagnetic proportional valve, 30: second electromagnetic switching valve, 34 ...
2nd switching valve, 35 ... 1st pressure pickup, 36 ... 2nd
Pressure pick-up, 37 ... third pressure pick-up, 38
... Electronic control unit (ECU), 39 ... Tractor-side coupler for trailer service line A, 40 ... Tractor-side coupler for trailer supply line B, 41 ... Trailer-side air brake system, 43,44 ... Left and right front wheel power chamber, 45, 46 ... power chamber for left and right rear wheels, 47
... relay valve for trailer, 51 ... steering angle sensor, 52 ...
Tractor / trailer relative angle sensor, 53: vehicle turning determination means, 54: relative angle change determination means, 55: brake ratio calculation means, 56: target brake ratio setting / change means

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takashi Kushiyama 1464-4 Moon Ring, Namerikawa-cho, Hiki-gun, Saitama Prefecture Inside JK Truck Truck Brake Systems Co., Ltd. Wheel 1464-4 Inside JK Truck Truck Brake Systems Co., Ltd.

Claims (6)

[Claims] 1. A brake control device for a tractor and a trailer connected to each other via a coupler, wherein the brake control of the trailer is controlled by air pressure output from a brake valve provided on the tractor. A tractor / trailer brake control device that performs a brake control so that a brake ratio of a trailer calculated using at least a coupling force applied to the tractor by the trailer via the coupler is a target brake ratio, Vehicle turning judgment means for judging whether or not the tractor is being steered and outputting the result; and a change in the relative angle between the tractor and the trailer being steered based on an output signal from the vehicle turning judgment means. When it is smaller than the value, a trailer swing avoidance control signal is output and Means for outputting a signal for maintaining the current brake control when the change in the relative angle is not smaller than the first predetermined value, the brake control apparatus for a tractor / trailer. 2. The steering system according to claim 1, wherein the change in the relative angle during steering is the first.
Means for outputting a jackknife avoidance control signal when the change in the relative angle is not less than a predetermined value and is greater than or equal to a second predetermined value larger than the first predetermined value. A tractor / trailer brake control device according to claim 1. 3. A jackknife avoidance control signal is output based on an output signal from the vehicle turning determination means, when steering is not being performed and a change in the relative angle between the tractor and the trailer is greater than a third predetermined value. And a means for outputting a signal for maintaining the current brake control when the steering is not being performed and the change in the relative angle is not greater than the third predetermined value. A tractor / trailer brake control device as described. 4. A brake control device for each of a tractor and a trailer connected to each other via a coupler, wherein the brake control of the trailer is controlled by an air pressure output from a brake valve provided on the tractor. A tractor / trailer brake control device that performs brake control so that a brake ratio of a trailer calculated using at least a coupling force applied to the tractor by the trailer via the coupler becomes a target brake ratio, Vehicle turning judgment means for judging whether or not the tractor is being steered and outputting the result; and, based on an output signal from the vehicle turning judgment means, a change in the relative angle between the tractor and the trailer being determined not to be steering. When the value is larger than the value, a jackknife avoidance control signal is output and And a means for outputting a signal for maintaining current brake control when the change in the relative angle is not greater than the predetermined value. 5. The trailer swing avoiding control is executed by lowering the target brake ratio of the trailer and performing pressure reduction control of the trailer brake. A tractor / trailer brake control device as described. 6. The tractor according to claim 3, wherein the jackknife avoidance control is executed by increasing the target brake ratio of the trailer and performing pressure increase control of the trailer brake. -Trailer brake control device.