JP2000159087A - Brake device of vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the braking ability of a retarder of a vehicle in a wide speed range from the low to high, wherein the retarder serves as a third brake and the vehicle is further equipped with a foot brake device and exhaust gas brake device. SOLUTION: With the output shaft 4 of an engine 1, a torque converter 5, transmission 6, and final speed reducer 2 are coupled one after another to constitute a driving force transmitting system of a vehicle, and a first retarder 11 is installed between the torque converter 5 and transmission 6 of the power transmitting system while a second retarder 12 is installed on the opposite side to the torque converter 5 centering on the transmission 6, and the vehicle is braked through the operation of at least either of the first 11 and second retarders 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle braking device, and more particularly to a vehicle braking device provided with a retarder in addition to a foot brake device and an exhaust brake device.

[0002]

2. Description of the Related Art In general, heavy vehicles such as large vehicles and large special vehicles equipped with construction equipment are equipped with an exhaust brake device in addition to a foot brake device (first brake) for braking an accelerator by depressing a foot pedal. (Second brake) is provided. The exhaust brake device is a device that causes a forced pumping loss in an engine by closing an exhaust passage by an exhaust brake valve, and brakes a vehicle by the pumping loss.
It does not have a friction braking mechanism such as a foot brake device, and has an advantage that it can prevent the abrasion of a brake lining at an early stage and the occurrence of a fade phenomenon. For this reason, it is used as a main brake in place of the foot brake, particularly when descending a long downhill, and the foot brake device is used as an auxiliary. However, since the displacement of the engine is constant, when the size of the vehicle is increased and the size of the load is increased to increase the weight, the braking ability of the exhaust brake is substantially reduced. Therefore, it is desired to increase the braking force by the third brake.

FIGS. 3 and 4 are block diagrams showing a vehicle driving force transmission system provided with a foot brake device and an exhaust brake device, each showing an example in which a retarder is installed as a third brake.

3 and 4, reference numeral 1 denotes an engine, 2
Denotes a final reduction gear, and 3 denotes an axle shaft. A transmission 6 is connected to an output shaft 4 of the engine 1 via a torque converter 5, and the final reduction gear 2 is connected to the transmission 6 via a propeller shaft 7. The wheels 8, 8 are attached to the axle shafts 3, 3 of the final reduction gear 2, respectively, to form driving force transmission systems 9, 10.

As shown in FIG. 3, a first retarder 11 is mounted between the torque converter 5 and the transmission 6 in the former driving force transmission system 9 for braking. As shown in FIG. 4, the system 10 includes a second transmission on the side of the final reduction gear 2 with the transmission 6 interposed therebetween.
Are mounted.

[0006]

SUMMARY OF THE INVENTION The first retarder 1
The first and second retarders 12 are braking devices that apply braking force to the driving force transmission systems 9 and 10 so as to prevent rotation, respectively. For example, the first and second retarders 12 are eddy current type retarders that use eddy currents, Retarder, braking by work,
Further, as disclosed in Japanese Patent Application Laid-Open No. 7-293606, a retarder configured to brake by rotating the rotating work of a rotating shaft into a stirring or compression work of a fluid (oil, air, etc.). It has been known.

Since neither of the retarders 11 and 12 has a friction braking mechanism, the retarders 11 and 12 have an advantage of preventing the abrasion of the brake lining and the occurrence of a fade phenomenon similarly to the exhaust brake device, and are used together with the exhaust brake device. As a result, a large braking force is generated.

The magnitude of the braking force of the first retarder 11 and the second retarder 12 is determined by the former driving force transmission system 9.
It is proportional to the input rotation speed of the transmission 6, and in the latter driving force transmission system 10, it is proportional to the output rotation speed of the transmission 6. Accordingly, in the former driving force transmission system 9, the speed reduction ratio increases due to the downshifting of the transmission 6 at low speeds.
The driving force transmission system 10 can transmit a large braking force corresponding to the rotational speed to the axle shafts 3 at high speed.

However, in the former driving force transmission system 9, when the speed is high, the reduction ratio is reduced by upshifting, so that the braking force is insufficient. In the latter driving force transmission system 10, the rotation speed at the low speed is low. However, there is a disadvantage that the braking force is insufficient due to a decrease in the braking force.

Therefore, in the two driving force transmission systems 9 and 10, when the first retarders 11 and 12 and the exhaust brake device are used together when the vehicle is going downhill on a steep slope, the braking force may be insufficient depending on the vehicle speed. Yes, the frequency of use of the foot brake device must be increased in order to respond.

Therefore, in a vehicle equipped with a foot brake device, an exhaust brake device, and a retarder, there arises a technical problem to be solved in order to perform sufficient braking by the retarder in a wide range from low speed to high speed. Thus, an object of the present invention is to solve the problem.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a vehicle braked by at least one of a foot brake device and an exhaust brake device, in which a torque converter, a transmission, and a final reduction gear are mounted on an output shaft of an engine. The driving force transmission system of the vehicle is constituted by sequentially connecting the transmission, and a retarder is mounted between the torque converter and the transmission of the power transmission system and on the opposite side of the torque converter with the transmission as a center, and one or both of these retarders are operated. An object of the present invention is to provide a vehicle braking device configured to brake a vehicle.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail with reference to FIGS. The same components as those described in the related art are denoted by the same reference numerals, and description thereof will be omitted.

FIG. 1 shows a block diagram in which a retarder is installed in a power transmission system of an engine that connects an engine of a vehicle having a foot brake device and an exhaust brake device to a final reduction gear.

In FIG. 1, reference numeral 1 denotes an engine provided with an exhaust brake device, and reference numeral 5 denotes a torque converter for continuously changing the output torque of the engine using oil. A power transmission system between the torque converter 5 and the transmission 6, specifically, a first leader 11 is mounted to brake between the output shaft 13 of the torque converter 2 and the input shaft 14 of the transmission 6. A second retarder 12 is mounted on the opposite side of the torque converter 5 via a transmission shaft 15.

The first retarder 11 and the second retarder 12 are an eddy current retarder, a power generation retarder,
Alternatively, the first retarder 11 is composed of a fluid type retarder that consumes energy by agitating work of a fluid (such as air or oil) or the like, and the first retarder 11 consumes the rotational torque between the torque converter 5 and the transmission 6 by adding a resistance force. Brakes the axle shafts 3, 3, and the second retarder 12 applies resistance to the rotational torque of the transmission 6 and consumes the torque so that the axle shafts 3, 3
Brake. Therefore, when the first and second retarders 11 and 12 are simultaneously used to brake the axle shafts 3, 3, the first retarder 1
1 will act as the main brake and the second retarder 12 will act as the auxiliary brake. Also, during high-speed traveling, the second retarder 12 functions as a main brake,
Of the retarder 11 functions as an auxiliary brake.

FIG. 2 shows the independent braking ability of the first retarder 11 and the second retarder 12 with respect to the vehicle speed and the combined braking ability of the two retarders 11, 12 with respect to the vehicle speed. As shown in the figure, the braking force of the first retarder 11 is almost inversely proportional to the vehicle speed, and the braking force of the second retarder 12 is almost proportional to the vehicle speed. Therefore, the first retarder 11
And the second retarder 12 together, the first
A large combined braking force is generated by the independent braking of the retarder 11, and a large combined braking force mainly by the second retarder 12 is generated at a high speed.

As described above, when the two retarders 11 and 12 are simultaneously operated, one of the retarders serves as a main brake and the other retarder serves as an auxiliary brake, so that a stable and high braking force can be obtained in a wide range from low speed to high speed. Can be. Therefore, the conventional disadvantage that the braking force varies depending on the installation position of the retarder is solved, and the safe braking traveling on a steep descent is enabled.

As shown in FIG. 1, the first retarder 11 and the second retarder 12 can operate independently of each other, and both retarders 11 and 12 can operate simultaneously. Since it is possible, the retardation can be reduced to a target vehicle speed by selecting the selection of the retarder and the selection of the individual or the combination in accordance with the vehicle speed. For example, when the vehicle is selected for normal downhill driving, long downhill driving, or low-speed running on flat ground (auto cruising), and if necessary, an exhaust brake device and a foot brake device are used in combination. Less braking travel is possible,
At the time of a steep descent, if the first retarder 11 and the second retarder 12 are used together with an exhaust brake device and, if necessary, a foot brake is used, extremely safe braking travel becomes possible. For this reason, the frequency of use of the foot brake device is greatly reduced as compared with the related art, and abnormal wear of the brake lining can be suppressed, and the occurrence of a fade phenomenon can be prevented.

The selection of the first retarder 11 and the second retarder 12 can be performed automatically. For example, a transmission 6 or a shift device of the transmission 6 is provided with a sensor for detecting a shift position and a vehicle speed sensor for detecting a vehicle speed from the final reduction gear 2 or the like, and a controller (microcomputer, sequencer, etc.) Is stored in a memory, and a map of the relationship between each change data and the shift position is stored. Based on the actual vehicle speed and the shift position, the controller uses the retarder for single braking, combined braking, or single braking. If the retarder is determined and a control program for operating the retarder based on the determination is stored, safe braking can be performed only by activating the controller by the switch. Needless to say, a device for detecting a road condition (gradient) is installed, and whether a slope, a flat ground, a steep slope or a gentle slope is used as a determination element of the program, and the selection of the above-described retarder is switched based on the determination element. Precise control becomes possible. In addition, the exhaust brake device is normally switched manually, but can be added as an object to be controlled by the program.

As described above, various modifications can be made to the present invention without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

[0022]

According to the present invention, as described in detail in the above embodiment, a retarder is mounted between a torque converter and a transmission of a driving force transmission system of a vehicle and on the opposite side of the torque converter with respect to the transmission. The vehicle is configured to brake the vehicle by one or both operations. For this reason, a large braking force can be obtained without unnecessarily increasing the displacement of the engine and irrespective of the speed of the vehicle body. In addition, since the retarder can be used on both a slope and a flat road, if at least one of the exhaust brake device and the retarder is used in combination according to the road gradient, it is possible to safely go downhill even when steeply descending. In addition, since the retarder can also be used as the main brake, it is possible to prevent the abrasion of the brake lining and the occurrence of a fade phenomenon as compared with the conventional one, and to reduce the burden on the foot brake operation and reduce driver fatigue. In addition, the present invention has a remarkable effect.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a block diagram in which a retarder is installed in a power transmission system of an engine that connects an engine of a vehicle and a final reduction gear.

FIG. 2 is a diagram illustrating a change in a braking ability with respect to a vehicle speed when a first retarder and a second retarder are used alone, and a change in a combined braking capacity with respect to a vehicle speed when a first retarder and a second retarder are used together; It is a performance diagram.

FIG. 3 is a block diagram showing a power transmission system of a conventional vehicle, in which a retarder is installed between a torque converter and a transmission.

FIG. 4 is a block diagram showing a power transmission system of a conventional vehicle, and showing an example in which a retarder is installed on the opposite side of a torque converter with respect to a transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Final reducer 3 Axle shaft 4 Engine output shaft 11 First retarder 12 Second retarder

Claims (1)

[Claims] In a vehicle braked by at least one of a foot brake device and an exhaust brake device, a torque converter, a transmission, and a final reducer are sequentially connected to an output shaft of an engine to form a driving force transmission system of the vehicle. A vehicle characterized in that a retarder is mounted between the torque converter and the transmission of the driving force transmission system and on the opposite side of the torque converter with the transmission as the center, and the vehicle is braked by actuation of one or both of the retarders. Braking device.