JPH08327479A - Braking force controller - Google Patents

Abstract

PURPOSE: To obtain such a braking state that the braking force of each wheel is stably utilized to the maximum without giving any influence to the total braking force of the wheels by directly detecting the state of the braking force of each wheel. CONSTITUTION: Such a braking state that the braking force of each wheel is stably utilized to the maximum without giving any influence to the total braking force of the wheels by directly detecting the state of the braking force of each wheel by fitting strain gauges 29 to the anchor brackets of drum brakes 28 which obtain braking forces by bringing brake shoes 32 into contact with drums 31 with pneumatic pressures PL and PR and detecting the strains in the brackets 33 as braking forces FL and FR with the strain gauges 29, and then, providing a controller 9 which supplies air so as to make the braking forces FL and FR equal to each other and, when the braking forces FL and FR at front wheels 5L and 5R become different to each other, eliminating the difference regardless of the state of the road surface, etc., by actuating the drum brakes 31 by supplying pneumatic pressures PL and PR so as to decrease the braking force of the wheel 5 on the higher braking force side and increase the braking force of the wheel on the lower braking force side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force control device for controlling a braking force by directly detecting a braking torque of a braking device.

[0002]

2. Description of the Related Art A general braking system for an automobile sends a fluid (for example, air) to a brake chamber through a brake valve which operates in conjunction with the depression of a brake pedal, and the brake shoe is driven by the air pressure sent to the brake chamber. Is operated to bring the brake shoe into contact with a rotating body that rotates integrally with the wheel to obtain a braking force by frictional force. Brake chambers are provided for each of the front, rear, left, and right wheels individually, and braking force is applied to each wheel individually according to the running state of the vehicle and the road surface condition, etc., to perform control to stabilize the behavior of the vehicle during braking. be able to. Also, especially for large vehicles and trailer vehicles, by applying braking force to each wheel individually according to the load capacity of the load,
It is possible to perform control such that the generated deceleration is constant regardless of the load amount.

Further, conventionally, there has been proposed a braking force control device (for example, see Japanese Patent Laid-Open No. 1-212655) that detects the braking force of the braking device and stabilizes the behavior of the vehicle during braking. The conventional braking force control device is provided with braking force detection means on the axles of the left and right wheels, and detects bending (torsion) distortion in the front-rear direction of the axle generated by the force acting between the vehicle body and the wheels as a braking force. The braking force on one side is reduced to eliminate the one-sided effect during braking. This makes it possible to stabilize the behavior of the vehicle during braking.

[0004]

However, in the conventional braking force control device, since the braking force detecting means is provided in the axle, the load input other than the braking force is detected. That is,
In addition to braking force, the axle has load inputs with large vertical loads and large lateral forces.If a braking force detection means is provided on the axle, it is difficult to detect deformation other than braking force and to detect only braking force. is there. Further, since the braking force of the higher one of the left and right wheels is reduced, the total braking force is reduced and the braking force cannot be utilized to the maximum.

The present invention has been made in view of the above situation, and a braking force control apparatus that directly detects the state of the braking force of each wheel to obtain a stable braking state without affecting the total braking force. The purpose is to provide.

[0006]

The structure of the present invention for achieving the above object is mounted on a member fixed to the vehicle body side of a braking device for obtaining a braking force by a fluid pressure and receives from a rotating portion of the braking device. A braking force detecting means for detecting an input as a braking force, a braking force generating means for controlling the fluid pressure to generate a braking force for the left and right wheels, and a braking force for the left and right wheels detected by the braking force detecting means are input. And a control device for operating the braking force generating means so as to eliminate the difference in braking force between the left and right wheels.

The control device is characterized in that the braking force of the wheel on the high braking force side is reduced and the braking force of the wheel on the low braking force side is increased. The braking device is a drum brake that obtains a braking force by bringing a brake shoe into contact with a drum by air pressure, and the braking torque detecting means is attached to an anchor bracket fixed to the vehicle body side of the drum brake. It is a strain gauge.

[0008]

When the braking force of the left and right wheels is detected by the braking force detecting means during braking and a difference occurs in the braking force between the left and right wheels, the braking force generating means is operated so that the difference between the braking forces of the left and right wheels is eliminated. Eliminates the difference in braking force between the left and right wheels regardless of road conditions.

When the strain of the anchor bracket caused by the rotation of the brake drum during braking is detected as the braking force by the strain gauge and the braking force is different between the left and right wheels, the braking force of the wheel on the higher braking force side is detected. The drum brake is operated so as to decrease and increase the braking force of the wheel on the lower braking force side, thereby eliminating the difference in braking force between the left and right wheels regardless of road surface conditions.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the overall construction of a braking system for a large vehicle equipped with a braking force control system according to an embodiment of the present invention, FIG. 2 shows the front of a drum brake, and FIG. 3 shows a braking force control system. The main configuration is shown. In the illustrated example, the drum brake of a large vehicle is described as an example, but the present invention can be applied to a braking device of various vehicles such as a disc brake of a passenger vehicle.

A braking device for a large vehicle will be described with reference to FIG. As shown in the drawing, the dual brake valve 2 is operated by the brake pedal 1, and the operation of the dual brake valve 2 supplies air from the primary air tank 3 and the secondary air tank 4 to the front, rear, and trailer brake systems. .

Air is supplied from the secondary air tank 4 to the brake chamber 6 on the front wheel 5 side via a quick release valve 7 and a control valve (for ABS control, for example) 8 provided corresponding to each front wheel 5. It The control valve 8 is controlled by the controller 9, and the braking force is independently controlled so that the left and right front wheels 5 are not locked during braking. The quick release valve 7 is provided to expel air quickly when braking is released.

Further, the brake chamber 11 on the rear wheel 10 side
Air is supplied from the primary air tank 3 via a relay valve 12 and a control valve (for ABS control, for example) 13 provided corresponding to each rear wheel 10. The relay valve 12 is operated by the air from the load sensing proportioning valve (LSV) 14 acting as pilot pressure. The control valve 13 is controlled by the controller 9, and the braking force is independently controlled so that the left and right rear wheels 10 are not locked during braking. The LSV 14 is a valve that detects the load of the rear axle and adjusts the pressure by bending the suspension. The relay valve 12 is provided in the rear system with respect to the front because the piping and the chamber capacity are large.

On the other hand, in the brake chamber 16 of the trailer wheel 15, a trailer air tank 19 is provided via a relay valve 17 and a control valve (for ABS control, for example) 18 provided corresponding to the wheel 15 of each system. Is supplied with air. Relay valve 17
Is operated by the air from the dual relay valve 20 acting as pilot pressure, and the dual relay valve 20 is operated by the air from the front or rear system acting as pilot pressure. The control valve 18 is controlled by the trailer controller 21, and the braking force is controlled independently for each system so that the wheels 15 of the left and right systems are not locked during braking. Further, the dual relay valve 20 is operated by the trailer brake 22 that is manually operated, so that air can be supplied to the brake chamber 16 of the wheel 15 on the trailer side regardless of the brake pedal 1.

On the other hand, an auxiliary brake device for generating a braking force in the vehicle independently of the operation of the brake pedal 1 is provided, and the auxiliary brake device is operated based on a command from the controller 9. That is, the valve 23 for the exhaust brake that obtains the braking force by the flow resistance of the exhaust gas according to the throttle of the exhaust pipe and the valve 24 of the compression pressure release type engine brake auxiliary device that obtains the braking force by weakening the downward force of the piston are operated. When turned on by the switch 25, the exhaust brake and the compression pressure release type engine brake auxiliary device are operated by a predetermined combination based on a command from the controller 9. Further, when the valve 26 of the retarder, which obtains the braking force stepwise by giving the rotation resistance to the output shaft, is turned on by the control switch 27, the retarder of the number of stages selected by the control switch 27 is activated based on the command from the controller 9. To be done.

A drum brake 28 is provided as a braking device on each of the front wheels 5 and the rear wheels 10, and the drum brake 28 is a control valve 8, 13 and a brake chamber 6, 11 as a braking force generating means for generating a braking force.
Air is supplied through the. The braking force of the drum brakes 28 of the front wheels 5 and the rear wheels 10 is detected by a strain gauge 29 as a braking force detecting means, and information of the strain gauge 29 is input to the controller 9. Further, the wheel 15 is also provided with a drum brake 28 as a braking device, and air is supplied to the drum brake 28 via a control valve 18 and a brake chamber 16 as a braking force generating means for generating a braking force. There is. The braking force of the drum brake 28 of the wheel 15 is detected by the strain gauge 29, and the information of the strain gauge 29 is input to the trailer controller 21.

The structure of the drum brake 28 having the strain gauge 29 will be described with reference to FIG. In addition, front wheel 5 and rear wheel 1
0 and the drum brake 28 provided on the wheel 15 have the same configuration, and therefore the drum brake 28 provided on the front wheel 5 will be described as an example. The drum brake 28 spreads the pair of brake shoes 32 into contact with the drum 31 that rotates integrally with the front wheel 5 by pushing the pair of brake shoes 32 into contact with each other.
The braking force is generated in the. That is, the anchor bracket 33 is fixed to the axle of the vehicle body, and the brake shoe 3 is attached to the anchor bracket 33 via the anchor pin 34.
2 is rotatably supported. The tips of the brake shoes 32 are connected to each other by a wheel cylinder 35, and the pair of brake shoes 32 is spread by driving the wheel cylinder 35. The wheel cylinder 35 is driven by supplying air to the brake chamber 6. A brake lining 36 is attached to the outer peripheral surface of the brake shoe 32, and the pair of brake shoes 3 is driven by driving the wheel cylinder 35.
The brake pad 36 is pressed against the inner peripheral surface of the drum 31 that rotates integrally with the front wheels 5 when the tire 2 is spread. Reference numeral 37 in the drawing is a tension spring for rotating the brake shoe 32 inward when the brake is released.

A strain gauge 29 is attached to the anchor bracket 33 in order to detect the braking force of the drum brake 28. The strain gauge 29 is attached to the upper part of the anchor pin 34 (left side in the drawing) on the rear side in the rotation direction of the drum 31. During braking, the anchor bracket 33 receives a rotational force from the drum 31 via the brake shoe 32 and the anchor pin 34, and the strain gauge 29 detects the deformation acting on the anchor bracket 33. Strain gauge 29
When the strain is detected by, the electrical resistance changes according to the strain,
The braking force of the drum brake 28 is detected by the change in the electric resistance.

In the above braking device, the strain gauge 29 detects the braking force of the drum brake 28,
The control for eliminating the difference between the braking forces of the left and right wheels is executed. The braking force control device will be described based on FIG. 3 by taking the left and right front wheels 5 as an example. Controller 9 to control valve 8
The operation command is output to the air pressure in the brake chamber 6.
PL and PR are set and the drum brake 28 is activated.
During braking, the strain gauges 29 detect the braking forces FL, FR of the left and right front wheels 5L, 5R of the drum brake 28, and the braking forces FL, FR are input to the controller 9. The controller 9 compares the input braking forces FL and FR, and the air pressures PL and PR are the same as the braking forces FL and FR of the left and right front wheels 5L and 5R.
Is set and an operation command is output to the control valve 8.

The operation of the braking force control device will be specifically described with reference to FIG. When the braking force FL, FR of the left and right front wheels 5L, 5R detected by the strain gauge 29 during braking is read and both braking forces FL, FR are other than zero, that is, the difference between the braking forces FL, FR during braking is compared. To be done. As a result of comparison, braking force FL, FR
If the difference is a negative value, the braking force FR of the front wheels 5R is higher than that of the front wheels 5L.
Is large, the air pressure PL of the front wheels 5L is increased and the air pressure PR of the front wheels 5R is decreased. Also, as a result of the comparison,
When the difference between the braking forces FL and FR is positive, the front wheels are
Since the braking force FL of 5L is large, the air pressure PL of the front wheels 5L is reduced and the air pressure PR of the front wheels 5R is increased. Braking force
After adjusting the air pressures PL and PR so as to reduce the difference between FL and FR, compare the absolute value of the difference between the braking forces FL and FR with the specified value A and compare the absolute value of the difference between the braking forces FL and FR. The adjustment of the air pressures PL and PR for reducing the difference between the braking forces FL and FR is continued until is below the predetermined value A.

In this way, the controller 9 compares the braking forces FL, FR of the left and right front wheels 5L, 5R during braking, reduces the braking force of the front wheel 5 on the side with a high braking force, and reduces the braking force on the side with a low braking force. Air pressure PL, P to increase the braking force of front wheel 5
Since the R is adjusted so that the drum brake 28 is activated, the difference between the braking forces of the left and right front wheels 5L and 5R can always be suppressed without reducing the total braking force. Therefore, the road surface where the friction coefficient of the left and right road surface is different,
Regardless of the road surface condition, the difference in braking force between the left and right front wheels 5L and 5R can be suppressed within a range where stability can be secured. Also,
Stable braking can be performed by making maximum use of the braking force.
The braking force control described above can be similarly performed on the rear wheels 10 and the wheels 15.

By directly detecting the braking force F of the wheel with the strain gauge 29, the friction coefficient (road surface μ) of the road surface can be detected. That is, the road surface μ can be calculated by the road surface μ = braking force F / load W based on the load W and the braking force F when the wheels are locked. For this reason,
By detecting the braking force F of the wheel by the strain gauge 29, the braking force can be controlled according to the road surface μ.

The above embodiment shows an example of controlling the air supplied to the brake chamber 6 (brake chambers 11 and 16) via the dual brake valve 2 and the control valve 8 in accordance with the depression amount of the brake pedal 1. However, the air supply control is not limited to this. That is, as shown in FIG. 5, the sensor 41 detects the depression amount of the brake pedal 1, and the sensor 4
It is also possible to electrically operate the magnet valve 42 according to the output of 1 and supply the air from the secondary air tank 3 to the brake chamber 6 via the double check valve 43. At this time, the path from the control valve 8 is used for backup and the sensor 4
The air is mechanically supplied by depressing the brake pedal 1 when the air supply based on the signal from the No. 1 side is cut off.

The above-mentioned braking force control device detects the braking force of the left and right wheels to reduce the braking force of the wheel having the higher braking force and increase the braking force of the wheel having the lower braking force. Since the air pressures PL and PR are adjusted, the difference between the braking forces of the left and right wheels can be constantly suppressed without reducing the total braking force. Therefore, stable braking control can be performed by making maximum use of the braking force regardless of the road surface condition and the like. Further, the road surface μ can be calculated by detecting the braking force, and the braking force can be controlled according to the road surface μ.

[0025]

The braking force control device of the present invention is a braking force detecting means for detecting an input received from the rotating portion as a braking force, which is attached to a member fixed to the vehicle body side of a braking device for obtaining a braking force by a fluid pressure. , The braking force generation means for controlling the fluid pressure to generate the braking force for the left and right wheels, and the braking force for the left and right wheels detected by the braking force detection means are input, and the difference between the braking forces for the left and right wheels is eliminated. Since the braking force generation means is operated, the braking force of the left and right wheels is detected by the braking force detection means at the time of braking, and when the braking force is different between the left and right wheels, the difference between the braking forces of the left and right wheels is detected. It is possible to operate the braking force generating means so as to eliminate. As a result,
The braking force difference between the left and right wheels can be eliminated regardless of the road surface condition, etc., and the state of the braking force of each wheel can be directly detected to maximize the braking force stably without affecting the total braking force. It is possible to obtain the used braking state.

Further, in the braking force control device of the present invention, a strain gauge is attached to the anchor bracket of the drum brake which obtains a braking force by bringing the brake shoe into contact with the drum by air pressure, and the strain gauge controls strain of the anchor bracket. Since a control device that supplies air so that the difference in braking force is eliminated is detected as power, when a difference occurs in braking force between the left and right wheels, the braking force of the wheel with the higher braking force is reduced. The drum brake can be operated by supplying air to the state where the braking force of the wheel on the lower braking force side is increased. As a result, the difference in braking force between the left and right wheels can be eliminated regardless of the road surface condition, etc., and the state of the braking force of each wheel can be directly detected to stabilize the braking force without affecting the total braking force. It is possible to obtain the braking state that is utilized to the maximum.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a braking device for a large vehicle including a braking force control device according to an embodiment of the present invention.

FIG. 2 is a front view of a drum brake.

FIG. 3 is a configuration diagram of a main part of a braking force control device.

FIG. 4 is a flowchart of braking force control.

FIG. 5 is a main part configuration diagram showing another example of the braking device.

[Explanation of symbols]

 1 Brake Pedal 2 Dual Brake Valve 3 Primary Air Tank 4 Secondary Air Tank 5 Front Wheel 6 Brake Chamber 8 Control Valve 9 Controller 10 Rear Wheel 11 Brake Chamber 13 Control Valve 15 Wheel 16 Brake Chamber 18 Control Valve 28 Drum Brake 29 Strain Gauge 31 Drum 32 Brake shoe 33 Anchor brat 34 Anchor pin 35 Wheel cylinder 36 Brake lining

Claims (3)

[Claims] 1. A braking force detecting means, which is attached to a member fixed to a vehicle body side of a braking device for obtaining a braking force by a fluid pressure and detects an input received from a rotating portion of the braking device as a braking force, and the fluid pressure. The braking force generation means for controlling and generating the braking force of the left and right wheels, and the braking force of the left and right wheels detected by the braking force detection means are input, and the braking force is controlled so as to eliminate the difference between the braking forces of the left and right wheels. A braking force control device comprising: a control device that operates a power generation means. 2. The braking force according to claim 1, wherein the control device reduces the braking force of the wheel on the higher braking force side and increases the braking force of the wheel on the lower braking force side. Control device. 3. The braking device is a drum brake that obtains a braking force by bringing a brake shoe into contact with a drum by air pressure, and the braking torque detecting means is an anchor bracket fixed to the vehicle body side of the drum brake. The braking force control device according to claim 1 or 2, wherein the strain gauge is attached to the.