JPH0550902A - Braking device for vehicle - Google Patents

Abstract

PURPOSE:To obtain sufficient braking effect and to effectively suppress the abnormal rise of the temperature of brake oil. CONSTITUTION:The braking device has the first switch circuit 10 in which a brake switch 11, an acceleration switch 12 and a clutch switch 13 are connected in series, and one end of the first switch circuit 10 is connected to an electric power source 31, and the other end is connected to the switching control means 20 of an exhaust brake valve 15. The second switch circuit 3 in which a brake thermo-switch 1 functioning according to the temperature of brake oil and an inclination switch 2 functioning according to the inclination in the longitudinal direction of a car body are connected in series is connected in parallel to the brake switch 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle braking system, and more particularly to a vehicle braking system applied to a vehicle having an exhaust brake.

[0002]

BACKGROUND ART Generally, an exhaust brake that assists braking by a foot brake is adopted in a 4-cycle diesel engine vehicle such as a medium / large-sized truck or a bus. This exhaust brake is a type of engine brake, in which a valve is provided in the middle of the exhaust pipe of the engine, and this valve is closed to increase the resistance in the exhaust stroke.In other words, the engine works as a kind of compressor, The braking effect of the brake is increased. this is,
When the exhaust brake operates, the resistance due to compression is twice in one cycle, the compression stroke and the exhaust stroke. Therefore, the resistance due to compression is greater than the case where only engine braking occurs once in the compression stroke in one cycle. This is because a braking effect can be obtained. As types of the exhaust brake, there are an electric pneumatic type in which compressed air is controlled by an electric device to open and close an exhaust valve and an electric negative pressure pneumatic type in which negative pressure air is used instead of compressed air.

FIG. 2 shows a conventional example of a vehicle braking system including an electropneumatic exhaust brake. In this figure, a battery 3 as a power source whose negative side is grounded
On the positive side of 1, the brake switch 11, the accelerator switch 12, and the clutch switch 1 are connected via a fuse 32.
One end of a first switch circuit 10 formed by connecting 3 and 3 in series is connected. The other end of the first switch circuit 10 is connected to one end of an exciting coil 21A of an electromagnetic valve 21 that constitutes the opening / closing control means 20 of the exhaust brake valve 15, and the other end of the exciting coil 21A is grounded. Here, the brake switch 11 is a switch that is turned on when a brake pedal (not shown) forming a foot brake is depressed, and the accelerator switch 12 is released when the accelerator is turned off, that is, the accelerator pedal (not shown) is released. The clutch switch 13 is a switch that is turned on in the state, and the clutch switch 13 is a switch that is turned on when the clutch is connected, that is, in a state where the clutch pedal (not shown) is not depressed. At the connection point between the brake switch 11 and the accelerator switch 12, there is a pilot lamp 1 for braking.
4 is connected to one end, and the other end of the pilot lamp 14 is grounded. The opening / closing control means 20 for the exhaust brake valve 15 includes an electromagnetic valve 21 and the electromagnetic valve 2
An air tank 23 and a control cylinder 24 are provided at both ends of an air pipe 22 which is opened and closed by 1. And control cylinder 2
4 includes an intake manifold valve 27 and an exhaust manifold 2 provided on an intake manifold 26 of the engine 25.
An exhaust brake valve 15 provided inside the vehicle 8 is connected. Here, since the intake manifold valve 27 overlaps with the valve, the compressed air in the exhaust manifold 26 escapes into the intake manifold 26 through the cylinder of the engine 25 during the operation of the exhaust brake, and suddenly expands to generate noise. The intake manifold valve 27 is provided so as to prevent the occurrence thereof, so that the intake manifold valve 27 is closed in conjunction with the exhaust brake valve 15.

Next, the overall operation of the conventional example configured as described above will be described. When the driver releases his / her foot from the accelerator pedal and depresses the brake pedal while the vehicle is traveling, the brake switch 11, the accelerator switch 12 and the clutch switch 13 are all turned on when the clutch pedal is not depressed. Therefore, the battery 31 (+) → fuse 32 → brake switch 11 → accelerator switch 12 → clutch switch 1
A closed circuit composed of 3 → excitation coil 21A → ground → battery 31 (−) is formed, and the electromagnetic valve 21 operates.
By the operation of the electromagnetic valve 21, compressed air is supplied from the air tank 23 to the control cylinder 24, and the exhaust brake valve 15 is closed. At this time,
At the same time, the intake manifold valve 27 is also closed in conjunction, but in actuality, the intake manifold valve 27 is structured so as not to be closed completely in order to improve the braking effect. When the exhaust brake operates in this way,
As described above, the resistance due to compression is obtained twice in the compression stroke and the exhaust stroke in one cycle, and a large braking effect is obtained. On the other hand, in order to release the operation of the exhaust brake, the brake switch 11 and the accelerator switch 12 or the brake switch 11 and the brake switch 11 and The clutch switch 13 is turned off, the circuit to the electromagnetic valve 21 is cut off, the compressed air in the control cylinder 24 is discharged to the atmosphere, and the exhaust brake is automatically opened. For braking, the exhaust brake is automatically activated again by releasing the accelerator pedal and depressing the brake pedal while the clutch is engaged.

Incidentally, as the brake switches, in addition to those which are interlocked with the depression of the brake pedal, relatively many switches which are manually operated by the driver are adopted.
When such a brake switch is used, when the driver turns off this switch, the circuit to the solenoid valve remains disconnected, so the exhaust brake does not operate and the brake switch turns on. In this state, the exhaust brake is activated when the accelerator pedal is released while the clutch is engaged, that is, when the engine brake is activated.

[0006]

In the conventional foot brake, when the brake is frequently used on a long downhill or the like, the oil temperature of the brake is abnormally increased, bubbles are generated in the brake oil, and the brake is ineffective. The phenomenon sometimes occurred. However, in the conventional example shown in FIG. 2, the exhaust brake operates only when the brake pedal is depressed, that is, when the foot brake is used (when the brake is being applied during normal running). Although it is effective in terms of assisting, there is a disadvantage that it is difficult to prevent an abnormal rise in brake fluid temperature. When using a manually operated brake switch, it is possible to operate the exhaust brake without using the foot brake, but in order to prevent an abnormal rise in the brake oil temperature on downhills, etc., It was necessary to properly adjust the frequency of use of the foot brake according to the driver's feeling. That is,
If the foot brake is used infrequently, sufficient braking force cannot be obtained, and conversely, if the foot brake is used too often, sufficient braking force can be obtained, but an abnormal rise in brake fluid temperature cannot be prevented. Is.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the problems of the prior art, and an object thereof is to obtain a sufficient braking effect and to effectively suppress an abnormal rise in brake oil temperature. It is to provide a braking device for a vehicle capable of performing the above.

[0008]

In a vehicle braking system of the present invention, a brake switch for controlling the operation of an exhaust brake, an accelerator switch that is turned on when the accelerator is off, and a clutch switch that is turned on when the clutch is connected are connected in series. It has a first switch circuit. One end of the first switch circuit is connected to the power supply and the other end is connected to the opening / closing control means of the exhaust brake valve. Then, the brake thermo switch that is turned on when the brake fluid temperature reaches a predetermined set temperature and the tilt switch that is turned on when the vehicle is on a downhill above a predetermined slope by detecting the inclination in the front-rear direction of the vehicle body Switch circuit is connected in parallel to the brake switch. With such a configuration, the above-described object is to be achieved.

[0009]

The function of the clutch switch, the accelerator switch, and the tilt switch is turned on when the vehicle is traveling on a downhill with a predetermined gradient or more and the clutch is engaged and the accelerator is off. In this case, the brake fluid temperature is set to a predetermined set temperature. When it reaches, the brake thermo switch is also turned on, the battery current is supplied to the opening / closing control means of the exhaust brake valve regardless of whether the brake switch is turned on or off, and the exhaust brake valve is closed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIG. Here, the same components as those of the conventional example of FIG. 2 described above are denoted by the same reference numerals, and the description thereof will be omitted.

FIG. 1 shows the configuration of a vehicle braking device according to an embodiment of the present invention. This embodiment is characterized in that the second switch circuit 3 including the brake thermo switch 1 and the tilt switch 2 is connected in parallel to the brake switch 11 in the conventional example of FIG. Here, the brake thermo switch 1 is a switch that is turned on when the brake oil temperature reaches a predetermined set temperature, and the tilt switch 2 detects the tilt of the vehicle body in the front-rear direction and detects a slope downhill of a predetermined slope or more. It is a switch that sometimes turns on. Other configurations are the same as those of the conventional example shown in FIG.

According to the present embodiment having such a configuration, when the brake fluid temperature reaches a predetermined set temperature (when the vapor lock phenomenon is likely to occur) while traveling on a downhill having a predetermined gradient or more, When the engine brake is operated (the clutch is engaged and the accelerator is off), all of the brake thermo switch 1, the tilt switch 2, the accelerator switch 12, and the clutch switch 13 are turned on, so that the battery 31 (+ ) → fuse 32 →
Brake thermo switch 1 → tilt switch 2 → accelerator switch 12 → clutch switch 13 → excitation coil 21
A closed circuit composed of A → ground → battery 31 (−) is formed, and the electromagnetic valve 21 constituting the opening / closing control means 20 of the exhaust brake valve 15 operates. By the operation of the electromagnetic valve 21, compressed air is supplied from the air tank 23 to the control cylinder 24, and the exhaust brake valve 15 is closed. At this time, the intake manifold valve 27 is also closed at the same time. When the exhaust brake operates in this way, as described above, the resistance due to compression is obtained twice in one cycle, the compression stroke and the exhaust stroke, and a large braking effect is obtained, which increases unnecessary speed on the downhill. This allows the exhaust brake to operate without using the foot brake, and as a result, it is possible to effectively suppress an abnormal rise in the brake fluid temperature, and the above exhaust brake Is automatically performed simultaneously with the operation of the brake thermo switch 1 and the tilt switch 2, so that the driver consciously adjusts the frequency of use of the foot brake in order to prevent an abnormal increase in the brake fluid temperature. There is also the advantage of being released from.

[0013]

As described above, according to the present invention,
Engine braking is activated while driving downhill with a certain slope or more
When the brake fluid temperature reaches the specified set temperature in the state
Whether you are using a foot brake or not.
Instead, power is automatically supplied to the opening / closing control means of the exhaust brake valve.
The current is supplied and the exhaust brake valve is closed
Then, the exhaust brake operates automatically and the engine brake
The braking effect of can be increased by the exhaust brake.
Suppresses unnecessary increase in speed on downhill
And effectively suppress an abnormal rise in brake fluid temperature.
Can effectively control the occurrence of vapor lock phenomenon
Can be suppressed and the foot brake is used frequently.
The above effect without the driver consciously adjusting the degree
Providing an unprecedented excellent vehicle braking system that
Can be offered.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example.

[Explanation of symbols]

 1 Brake Thermo Switch 2 Tilt Switch 3 Second Switch Circuit 10 First Switch Circuit 11 Brake Switch 12 Accelerator Switch 13 Clutch Switch 15 Exhaust Brake Valve 20 Open / Close Control Unit 31 Battery as Power Source

Claims (1)

[Claims] 1. A first switch circuit in which a brake switch for controlling the operation of an exhaust brake, an accelerator switch that is turned on when the accelerator is off, and a clutch switch that is turned on when the clutch is connected are connected in series. In a vehicle braking device in which one end of a switch circuit is connected to a power source and the other end is connected to an opening / closing control means of an exhaust brake valve, a brake thermo switch that is turned on when the brake fluid temperature reaches a predetermined set temperature. And a second switch circuit in which a tilt switch for detecting the tilt of the vehicle body in the front-rear direction is connected in series with a tilt switch which is turned on when the vehicle is descending a predetermined slope or more, is connected in parallel to the brake switch. Vehicle braking system.