JP2004203378A - Parking brake device of tractor/trailer coupled car - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a parking brake device of a tractor/trailer coupled car having reduced consumption of working fluid, by operating a service brake of a trailer by necessary minimum working fluid pressure when a parking brake is operated. <P>SOLUTION: The parking brake device of a tractor/trailer coupled car comprises a standard chamber 10 for operating a service brake of the trailer, an air reservoir 14 for storing air, a trailer control valve 12 having an input/output characteristic for gradually reducing air supplied from the air reservoir 14 to the standard chamber 10 in response to increase of control pressure supplied to a control port 12B, a double check valve 22 for selectively outputting higher pressure of control pressures inputted into two input ports to a control port 12B of the trailer control valve 12, a hand control valve 20 for controlling control pressure inputted into one input port of the check valve 22 in response to an operation amount of a lever 20A, and a pressure reducing valve 24 for decompressing air in the air reservoir 14 to a predetermined pressure and inputting it into the other input port of the double check valve 22. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a parking brake device for a tractor / trailer coupled vehicle, and more particularly to a technique for reducing the consumption of working fluid.

  As a parking brake device for a tractor / trailer coupled vehicle, one disclosed in Non-Patent Document 1 has been put to practical use. That is, as shown in FIG. 4, a trailer control valve 4 operated and controlled by a hand control valve 3 is interposed between an air reservoir 1 for storing air as a working fluid and a standard chamber 2 for operating a service brake of a trailer. Be mounted. In addition, a relay valve 6 that is controlled by the hand control valve 3 is interposed between the air reservoir 1 and the spring chamber 5 that operates the parking brake of the tractor.

  When the lever 3A of the hand control valve 3 is operated to operate or release the parking brake, the control pressure is applied from the air reservoir 1 to the control port 4B of the trailer control valve 4 with the output characteristics shown in FIG. Supplied. In the trailer control valve 4, an air pressure corresponding to the control pressure input to the control port 4B is supplied to the standard chamber 2 with the input / output characteristics shown in FIG. As a result, as shown in FIG. 5B, air pressure is supplied to the standard chamber 2 according to the lever operation amount of the hand control valve 3, and the service brake of the trailer is activated or released. On the other hand, in the tractor, the spring chamber 5 is actuated by the air in the air reservoir 1 according to the control pressure supplied from the hand control valve 3 to the relay valve 6, and the parking brake is actuated or released.

Reference numerals 7 and 8, which are not explained, are an air reservoir and a brake valve for operating the standard chamber 2 by operating a brake pedal, respectively. At this time, in the trailer control valve 4, the air pressure determined by the control pressure supplied from the air reservoir 1 to the control port 4B with the operation of the lever of the hand control valve 3, and the control port from the air reservoir 7 with the operation of the brake pedal. Among the air pressures supplied to 4A, a high pressure air is selectively supplied to the standard chamber 2 as the output of the trailer control valve 4.
Nissan Diesel Kogyo, bodywork material [Large vehicle (semi-tractor system)], A790T-N KL-CK (T) system, KL-CW (T) system and bodywork material [Common Edition], 2000/4

  By the way, when the tractor / trailer combined vehicle is parked, the parking brake of the tractor is activated, so that the service brake of the trailer does not need to continue to operate at its maximum capacity. However, when the lever 3A of the hand control valve 3 is operated to the parking position, as shown in FIG. 5B, a pressure higher than the pressure required for parking (required pressure) is supplied to the standard chamber 2, so that the air reservoir The first air may be consumed excessively. If the air is excessively consumed, the operation of other air devices becomes unstable. Therefore, it is necessary to increase the capacity of the air reservoir 1 in anticipation of safety, which causes an increase in vehicle weight and cost. I was

  In view of the above-mentioned conventional problems, the present invention reduces the consumption of the working fluid by operating the service brake of the trailer with the minimum necessary working fluid pressure when the parking brake is operated. An object of the present invention is to provide a parking brake device for a tractor / trailer coupled vehicle.

  For this reason, according to the first aspect of the present invention, the actuator for activating the service brake of the trailer, the working fluid storing means for storing the working fluid of the actuator, and the control pressure supplied to the control port increase, Supply control means having input / output characteristics for gradually reducing the pressure of the working fluid supplied from the working fluid storage means to the actuator, and selectively controlling the high pressure among the control pressures input to the two input ports Selection output means for outputting to a control port of the means, control pressure control means for controlling a control pressure to be input to one input port of the selection output means in accordance with an operation amount of an operation element, and the other of the selection output means Control pressure input means for inputting a control pressure of a predetermined pressure to an input port of the tractor / trailer coupled vehicle. It is characterized in that form.

In the invention according to claim 2, the control pressure input means inputs the working fluid from the working fluid storage means to the other input port of the selection output means via a pressure reducing means for reducing the working fluid to a predetermined pressure. It is characterized by.
The invention described in claim 3 is characterized in that the decompression means decompresses the working fluid stored in the working fluid storage means at a predetermined decompression rate.

  According to the first aspect of the present invention, when the operation element of the control pressure control means is operated to operate the parking brake, a control pressure corresponding to the operation amount is input to one input port of the selection output means. . In the selection output means, since the control pressure of the predetermined pressure is input to the other input port, of the two input control pressures, the high control pressure is input to the control port of the supply control means. The supply control means has an input / output characteristic of gradually decreasing the working fluid pressure supplied to the actuator as the control pressure increases, so that the supply is supplied to the actuator even when the operation element is operated at a predetermined position or more. The working fluid pressure is limited to a predetermined pressure. Therefore, by appropriately setting the control pressure input to the other input port of the selection output means, the minimum working fluid required for parking is supplied to the actuator that operates the service brake of the trailer. As a result, excessive consumption of the working fluid is suppressed. Then, the minimum working fluid required for parking is supplied to the actuator that operates the service brake of the trailer, and the consumption of the working fluid can be reduced.

  According to the second aspect of the present invention, the working fluid is input from the working fluid storage means to the other input port of the selection output means via the pressure reducing means for reducing the working fluid to a predetermined pressure. Therefore, by appropriately setting the pressure after the pressure of the working fluid is reduced by the pressure reducing means, the pressure of the working fluid supplied to the actuator can be limited to a minimum necessary for exerting a braking force required for parking.

  According to the third aspect of the present invention, a fluid obtained by depressurizing the working fluid stored in the working fluid storing means at a predetermined decompression rate is input to the other input port of the selection output means. For this reason, even when the working fluid pressure in the working fluid storage means is significantly reduced due to consumption of the working fluid, it is possible to supply the working fluid to the actuator that operates the service brake of the trailer. Safety can be improved.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an overall configuration in which the present invention is applied to a tractor / trailer coupled vehicle.
Air is supplied to the standard chamber 10 as an actuator for operating the service brake of the trailer from an air reservoir 14 (working fluid storage means) for storing air as a working fluid via a trailer control valve 12 (supply control means). . In the trailer control valve 12, the air pressure supplied from the air reservoir 14 to the standard chamber 10 is controlled according to the control pressure supplied to the control port 12B, with the input / output characteristics shown in the drawing.

  In addition, air is supplied to the control port 12A from the air reservoir 18 that stores air as a working fluid to the trailer control valve 12 through a brake valve 16 that is controlled by a brake pedal operation. Of the air pressure determined by the control pressure supplied to the control port 12B and the air pressure supplied to the control port 12A via the brake valve 16, the trailer control valve 12 outputs a high pressure as the output of the trailer control valve 12. The function of selectively supplying the standard chamber 10 to the standard chamber 10 is provided. Therefore, when the driver depresses the brake pedal, air is supplied from the air reservoir 18 to the standard chamber 10, so that the service brake of the trailer can be operated arbitrarily.

  The control port 12B of the trailer control valve 12 is supplied with air as a control pressure from the air reservoir 14 via a hand control valve 20 (control pressure control means) and a double check valve 22 (selection output means). In the hand control valve 20, the air pressure supplied from the air reservoir 14 is controlled according to the operation amount of the lever 20A (operation element) with the output characteristic shown by the solid line in FIG. The double check valve 22 outputs the higher pressure of the two input pressures. The output of the hand control valve 20 is input to one of its input ports. As shown by a broken line in FIG. 2A, the other input port of the double check valve 22 is supplied with a control pressure from the air reservoir 14 via a pressure reducing valve 24 (pressure reducing means) for reducing the air to a predetermined pressure. Is supplied. The output port of the double check valve 22 is connected to the control port 12B of the trailer control valve 12. Here, a configuration in which air is input from the air reservoir 14 to the other input port of the double check valve 22 via the pressure reducing valve 24 corresponds to a control pressure input unit.

  On the other hand, air is supplied from the air reservoir 14 to the spring chamber 26 that operates the parking brake of the tractor via the relay valve 28. In the relay valve 28, the air pressure supplied from the air reservoir 14 to the spring chamber 26 is controlled according to the control pressure supplied from the hand control valve 20 to the control port 28A. Therefore, when the driver operates the lever 20A of the hand control valve 20 to operate the parking brake of the tractor / trailer coupled vehicle, the service brake of the trailer is activated and the parking brake of the tractor is activated, thereby improving safety. Can be done.

Next, the operation of the parking brake device having such a configuration will be described.
When the lever 20A of the hand control valve 20 is operated from the release position to the parking position to operate the parking brake, the air control pressure supplied to one input port of the double check valve 22 and the control port 28A of the relay valve 28 Decreases gradually to zero as shown by the solid line in FIG.

  Then, the control pressure supplied from the air reservoir 14 to the other input port of the double check valve 22 via the pressure reducing valve 24 is substantially constant as shown by the broken line in FIG. The result is as shown in FIG. That is, in the double check valve 22, of the control pressure supplied from the hand control valve 20 and the control pressure supplied through the pressure reducing valve 24, the high pressure one is selectively used as the control port 12B of the trailer control valve 12. Supplied to

  In the trailer control valve 12, the air pressure supplied from the air reservoir 14 to the standard chamber 10 is controlled according to the control pressure supplied to the control port 12B, as shown in FIG. Referring to the figure, as the operation amount of the lever 20A of the hand control valve 20 increases, the output pressure initially increases at a substantially constant rate, but when the lever 20A is operated to a certain position, the operation amount thereafter increases. Regardless, the output pressure becomes substantially constant.

  Therefore, by appropriately setting the air pressure after the pressure reduction by the pressure reducing valve 24, the air pressure supplied from the air reservoir 14 to the standard chamber 10 is limited to a minimum necessary for exerting the braking force required for parking, and excessive A large air consumption can be prevented. Further, since excessive air consumption is prevented, the volume of the air reservoir 14 mounted on the tractor can be reduced, and vehicle weight and cost can be reduced. Further, the reduction in vehicle weight also improves fuel efficiency and exhaust properties, and is therefore preferable from the viewpoint of the global environment.

On the other hand, when the lever 20A of the relay valve 28 is gradually operated to the parking position, air is discharged from the spring chamber 26 according to the control pressure supplied to the control port 28A, and the parking brake of the tractor is activated.
When the lever 20A of the hand control valve 20 is operated from the parking position to the release position to release the parking brake, the parking brake of the tractor and the service brake of the trailer are released through a similar process.

  By the way, the air stored in the air reservoir 14 is consumed by the operation of various air devices including the standard chamber 10 and the spring chamber 26, and has a characteristic that the pressure gradually decreases. As shown in FIG. 3A, the input / output characteristics of the trailer control valve 12 gradually change from the solid line to the broken line as the air pressure in the air reservoir 14 decreases. Therefore, when the air pressure decreases to some extent, when the lever 20A of the hand control valve 20 is operated to the parking position, the output pressure of the trailer control valve 12 becomes zero, and the parking brake of the trailer may not operate.

  Therefore, it is desirable to use a pressure reducing valve having a characteristic of reducing the input pressure at a predetermined pressure reduction rate as shown in FIG. In this way, even when the air pressure in the air reservoir 14 is significantly reduced, the output pressure from the trailer control valve 12 does not become zero, and air can be supplied to the standard chamber 10. Safety in parking the vehicle can be improved.

Configuration diagram of a tractor / trailer combined vehicle to which the present invention is applied The pressure change characteristics in the above are shown, (A) is an explanatory diagram of a control pressure supplied to a double check valve, (B) is an explanatory diagram of a control pressure supplied to a trailer control valve, and (C) is a supply diagram of a standard chamber. Diagram of air pressure applied 7A and 7B show a problem caused by a decrease in air pressure and a method for solving the problem. FIG. 7A is an explanatory diagram showing a change in input / output characteristics of a trailer control valve. FIG. Illustrated illustration Configuration diagram of a tractor / trailer combined vehicle to which the conventional technology is applied 7A and 7B show pressure control states in the same as above, and FIG. 7A is an explanatory diagram of a control pressure output from a hand control valve, and FIG. 7B is an explanatory diagram of an air pressure output from a trailer control valve.

Explanation of reference numerals

10 Standard Chamber 12 Trailer Control Valve 12B Control Port 14 Air Reservoir 20 Hand Control Valve 20A Lever 22 Double Check Valve 24 Pressure Reducing Valve

Claims (3)

An actuator for activating the service brake of the trailer,
Working fluid storing means for storing the working fluid of the actuator,
Supply control means having input / output characteristics for gradually decreasing the working fluid pressure supplied to the actuator from the working fluid storage means with an increase in the control pressure supplied to the control port;
Selection output means for selectively outputting a high pressure one of the control pressures input to the two input ports to a control port of the supply control means;
A control pressure control unit that controls a control pressure input to one input port of the selection output unit according to an operation amount of the operation element;
Control pressure input means for inputting a control pressure of a predetermined pressure to the other input port of the selection output means,
A parking brake device for a tractor / trailer coupled vehicle, comprising:   2. The control pressure input means inputs the working fluid from the working fluid storage means to the other input port of the selection output means via a pressure reducing means for reducing the working fluid to a predetermined pressure. Parking brake system for tractor / trailer connected vehicles.   3. The parking brake device for a tractor / trailer coupled vehicle according to claim 2, wherein the pressure reducing means reduces the working fluid stored in the working fluid storing means at a predetermined pressure reduction rate.

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