JPH0370669A - Braking device for connected vehicle - Google Patents

Abstract

PURPOSE:To prevent generation of so-called jackknife phenomenon while a trouble, in which braking action is automatically generated at the time of reversing, by providing constitution so as to actuate a hydraulic brake device in an operation vehicle side by utilizing a pressure of oil in an accumulator provided in a tractive vehicle side. CONSTITUTION:In a tractive vehicle 10, an accumulator 34, possible to accumulate a pressure of oil in a cargo-handling hydraulic device 16 driven by an engine 14, and a brake action detecting device 54, for detecting a brake action condition of the vehicle 10, are provided. While in a transport vehicle 12 connected and trailed by this vehicle 10, a hydraulic brake device 58, having a master cylinder 60, is provided, and a supply condition of pressure oil to an operating pressure chamber 62 of the master cylinder 60 can be selected by a solenoid selector valve 66. The solenoid selector valve 66 is controlled in a manner wherein the pressure oil in the operating pressure chamber 62 is discharged, when inoperation of a brake is detected in the brake action detecting device 54, while the pressure oil in the accumulator 34 is actuated in the operating pressure chamber 62 when the brake action is detected.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a connected vehicle in which a towing vehicle equipped with an engine, such as a forklift truck, and a transport vehicle without a drive device are connected together. The present invention relates to a braking device.

(B) Conventional technology Conventional brake systems for coupled vehicles include a hydraulic brake system installed on the towing vehicle itself and a brake system installed on the transport vehicle that uses inertia. . When the towing vehicle is braked by its hydraulic brake system while traveling, the transport vehicle being towed by the towing vehicle is not dispatched, so the transport vehicle exerts a thrust on the towing vehicle due to inertia. . Therefore, a force in a compressive direction acts on the traction arm that connects the traction vehicle and the transport vehicle. The compressive force acting on this traction arm is applied to a master cylinder on the transport vehicle side, and the brake hydraulic pressure generated thereby operates the brakes provided on the wheels of the transport vehicle.

Therefore, the towing vehicle and the transport vehicle are braked by independent brake devices.

(c) Problems to be Solved by the Invention However, the conventional braking device for a coupled vehicle as described above has a problem in that the brake device of the transportation vehicle automatically operates when the coupled vehicle attempts to move backward. There are also problems in that the so-called jackknife phenomenon is likely to occur.

In other words, when an attempt is made to move the coupled vehicle backwards, a thrust force acts between the towing vehicle and the transport vehicle, which activates the brake system of the transport vehicle and brakes the vehicle.
This means that it will not be possible to retreat smoothly.

Furthermore, since the brake system of the transport vehicle is activated only when a predetermined thrust is applied between the towing vehicle and the transport vehicle, thrust is always acting when the transport vehicle is in a braking state. When the towing vehicle turns, a force in a bending direction acts on the joint between the towing vehicle and the transport vehicle, resulting in the so-called jackknife phenomenon.

The present invention aims to solve these problems.

(d) Means for Solving the Problems The present invention relates to a hydraulic system for a towing vehicle. +1. The above problem is solved by accumulating pressure and using the accumulated pressure to operate a hydraulic brake device of a transportation vehicle. That is, the braking device according to the present invention for a coupled vehicle consisting of a towing vehicle equipped with an engine and a hydraulic bag 77, and a transport di-vehicle connected to two towing Li vehicles and towed by the towing vehicle ( 10) is provided with a pressure accumulation device (34) and a brake operation detection device (54), and the transportation vehicle (12) is provided with an electromagnetic switching valve (66) and a hydraulic brake device (58). is capable of accumulating the hydraulic pressure of a cargo handling hydraulic system (16) operated using the engine (14) as a drive source, and the brake operation detection device is capable of detecting operation of the brake (50) of the towing vehicle, The hydraulic brake system of the transportation vehicle has a master cylinder (6) for braking the transportation vehicle.
0), and the electromagnetic switching valve can switch the state of supply of hydraulic pressure to the working pressure chamber (62) of the master cylinder,
The pressure accumulator of the towing vehicle and the electromagnetic switching valve r of the transport vehicle are hydraulically connected by piping, the brake operation detection device and the electromagnetic switching valve are electrically connected by wiring, and the electromagnetic switching valve If no operation is detected, drain the hydraulic pressure in the master cylinder's operating pressure chamber,
When the brake operation detection device detects the operation of the brake, it is configured to cause the hydraulic pressure of the pressure accumulator to act on the operation pressure chamber of the master cylinder. Note that the symbols in parentheses indicate corresponding members in the embodiments described later.

(E) If the brake system of the towing vehicle is activated while driving,
This is detected by the brake operation detection device. As a result, the electromagnetic switching valve is switched, and hydraulic pressure is supplied to the operating pressure chamber of the master cylinder of the transportation vehicle using the pressure accumulator as the hydraulic pressure source, and the hydraulic brake device of the transportation vehicle is activated.

This brakes both the towing vehicle and the transport vehicle. When reversing, the hydraulic brake system of the transport vehicle does not operate automatically, and braking is performed only when the brake pedal of the towing vehicle is operated. Furthermore, since the hydraulic brake device of the transport vehicle operates even when no thrust is applied from the transport vehicle to the towing rtZ 1aii, it is possible to prevent the occurrence of the so-called shack-knife phenomenon.

It is also possible to add a switching valve so that the hydraulic brake system of the transport rat can be activated only in case C when the transport vehicle is exerting even a slight thrust on the towing vehicle. (First Example) FIG. 1 shows a first example. In FIG. 1, the towing type 110O is shown on the left side divided by the broken line in the center, and the transport vehicle 12 is shown on the right side.

Towing IL (Both 10 have an engine 14 and a hydraulic system 16 for cargo handling.The hydraulic system 16 is connected to the engine 14.
Hydraulic pump 18, oil reservoir 2 driven by
0, the manual operation valve 22, mast cylinder 24, operation cylinder 26, etc. are blocked. A conduit 28 on the discharge side of the hydraulic pump 18 is connected to a pressure accumulator 34 via a throttle valve 30 and a reverse +)-f r:32. The hydraulic pressure accumulated in the pressure accumulating device 34 is adjusted by a pressure regulating valve 36 so that it does not exceed a predetermined value. Note that the oil pressure of the pressure accumulator 34 is measured by a pressure gauge 38.
can be monitored by A pipe line 40 to which hydraulic pressure from the pressure accumulator 34 is supplied is connected to a hydraulic joint 42, and a pipe line 46 for returning nb to the oil reservoir 20 via a check valve 44 is connected to a hydraulic joint 48. I'm doing 1.

The towing vehicle 10 has a hydraulic brake device 50, and by operating a brake pedal 52 thereof, the towing vehicle 10 can be braked. brake pedal 52
A brake pedal switch 54 is provided which is turned on when the brake pedal is stroked by a predetermined amount or more, and a signal from this switch is sent to an electric joint 56.

First, the transport vehicle 12 has a hydraulic brake device 58 activated, and by applying hydraulic pressure to the activation chamber 62 of the master cylinder 60, the XIl transport vehicle 12 can be braked. A conduit 64 connected to the operating pressure chamber 62 is connected to a conduit 68 or a conduit 70 by an electromagnetic switching valve 66 .

A hydraulic joint 72 is provided in the conduit 68, and a hydraulic fiber 74 is provided in the conduit 7o. Hydraulic joint 42
and the hydraulic joint 72 are removable, and the hydraulic joint 48
and hydraulic joint 74 are removable. Note that the pipe line 68 and the pipe line 70 are further provided with a hydraulic joint 76 and a hydraulic fiber 78 for connection with other transportation vehicles. An electric signal 1 for operating the electromagnetic switching valve 66 is inputted from an electric joint 80 . The electrical coupling 80 is detachable from the electrical coupling 56. Note that another electric fiber joint 82 is connected to the electric joint 80 for connection to another transportation vehicle.

Next, the operation of this embodiment will be explained. The towing vehicle 10 and the transport vehicle 12 are connected by a towing arm (not shown), and at the same time, the electric coupler 56 is connected to the electric joint 80.
The hydraulic joint 42 and the hydraulic fiber 48 are connected to the hydraulic clasp 72 and the hydraulic fiber 74, respectively. When the engine 14 is started, the 411-pressure pump 18 outputs hydraulic pressure to the pipe line 28. When hydraulic pressure is applied to the mast cylinder 24 or the operating cylinder 26 by operating the manual operating valve 22, the hydraulic pressure in the conduit 28 becomes -E, and the hydraulic pressure is accumulated in the pressure accumulating device 34. The oil pressure stored in the pressure accumulator 34 can be monitored by a pressure gauge 38. If the oil pressure becomes too high, oil is returned to the oil reservoir 20 by the relief action of the pressure regulating pull 36. In addition, throttle valve 3
The opening degree of 0 is adjusted to 4A to prevent the hydraulic pressure on the pipe line 28 side from decreasing due to pressure accumulation in the pressure accumulating device 34.

Since the brake pedal switch 54 is off when the brake pedal 52 of the towing vehicle 10 is not operated, the electromagnetic switching valve 66 connects the pipe line 64 and the pipe line 70,
No hydraulic pressure is acting on the working pressure chamber 62 of the master cylinder 60. Therefore, the hydraulic brake device 58 of the transportation vehicle 12 is in an inactive state.

Next, the brake pedal 52 of the towing vehicle 10 is operated to stroke a predetermined amount (to achieve a predetermined braking state).
, the brake pedal switch 54 is turned on, and the electromagnetic switch '#66 is turned off. That is, the conduit 68 and the conduit 64 are connected. Therefore, the pressure in the pressure accumulator 34 is increased to the pressure in the pipe 40. It acts on the working pressure chamber 62 through the hydraulic clasp 42, the hydraulic joint 72, the conduit 68, the electromagnetic switching valve 66, and the conduit 64.

Therefore, the master cylinder 60 is connected to the hydraulic brake device 5.
8 is activated, and the transport jlj and both 12 are braked. In this case, if the braking force on the transportation vehicle 12 side obtained by the hydraulic brake device 58 is made slightly larger than the braking force on the towing vehicle 10 side obtained by the Urakana brake device 50, the transportation vehicle 12 to towing vehicle 10
No thrust is applied to the cylinder, and the so-called jackknife phenomenon does not occur.

Next, when the brake pedal 52 is released, the brake pedal switch 54 is turned off, and the electromagnetic switching valve 66 enters a state in which the conduit 64 and the conduit 70 are connected. Therefore, the working pressure chamber 62 is connected to the pipe line 64, the electromagnetic switching valve 66, and the pipe line 70.
, Hydraulic Hand 74, ? The oil is returned to the oil reservoir 20 through the 111 pressure joint 4a, the conduit 46, and the check valve 44. As a result, the action of the Ura/-IE brake device 58 is released, and the braking state of the small transportation vehicle 12 is released. In addition, as mentioned above, il+ of the operating IE chamber 62 is connected to the oil reservoir 20.
11 pressure hands 42 and 48 and hydraulic pressure 11.
conduits 40 and 68 when connecting with two f-72 and 74;
The air mixed in the pipes 46 and 70 is discharged to the oil reservoir 20 side.

Therefore, the hydraulic fibers 42 and 48 and the hydraulic fibers 72 and 74
If the brake pedal 52 is operated at least several times after connection with the brake pedal, the air in the conduit will be discharged, and problems such as delayed brake operation and insufficient braking force caused by the mixed air will not occur.

In addition, in this example, 111 and 12 transportation vehicles with 1 JIL vehicle for towing and 0 vehicles were connected;
It is clear that the same effect can be obtained even if a similar transport vehicle 12 is further connected to the rear of the vehicle 2.

(Second Example) FIG. 2 shows a second example. This second embodiment is the same as the first embodiment except that a switching valve 82 operated by the thrust of the transport IIL 12 is provided. What about the switching valve 82? Direct magnetic switching valve 6
6 and the working pressure chamber 62 of the master cylinder 6o, and can switch the connection state between the working pressure chamber 62 and the electromagnetic switching valve 66. The switching of the switching valve 82 takes place by means of a traction arm 84 . That is, the towing arm 84 attached to the towing vehicle 1° has an elongated hole 86, and a bin 88 on the transport vehicle 12 side is inserted into this elongated hole 86.
are fitted together. A force is always applied to the towing arm 84 by a spring 90 in a direction that moves the towing vehicle 10 and the transport tomb 12 away from each other. In this second failed example, when the brake pedal 52 is operated to operate the hydraulic brake device 50 on the towing vehicle lO side, the towing vehicle lO
Since the thrust force directed toward the towing vehicle 10 acts on the towing vehicle 2, the switching valve 82 becomes in a state where it allows the supply of hydraulic pressure from the electromagnetic switching valve 66 to the working pressure chamber 62, and the hydraulic brake system is activated as in the case of the first embodiment. 58 is now available. If this braking force is larger than the braking force obtained by the towing rlj vehicle 1 both sides 0 side pressure brake device 50, the transportation vehicle 12 separates from the towing vehicle 11 (both 10), so the switching valve 82 is in the opposite state to the above-mentioned state. As a result, the hydraulic pressure no longer acts on the working pressure chamber 62, and the hydraulic brake device 58 has no braking action.By repeating the above operation, the braking force on the hydraulic brake device 58 side is reduced to the hydraulic brake state. The throttle valve 92 is maintained in a state corresponding to the braking force on the device 50 side.The throttle valve 92 prevents the switching block l-82 from entering the hunting state by relaxing the hydraulic pressure supplied to the working pressure chamber 62. This is to prevent
When the towing vehicle 10 and the transport vehicle 12 are reversing, the switching valve 82 is always in a state where hydraulic pressure can be supplied to the operating pressure chamber 62, so the braking action of the brake device 58 is controlled depending on the operating state of the electromagnetic switching valve 66. (braking action does not occur automatically just by moving backwards).

(G) Effects of the Invention As explained above, according to the present invention, the transportation rlj
Since the hydraulic brake devices on both sides were activated,
Unlike conventional brake systems that use inertia to operate the brakes, braking action does not occur automatically when reversing, and thrust is not applied from the transport vehicle to the towing vehicle during FDL movement. This prevents the occurrence of the so-called jackknife phenomenon.

[Brief explanation of drawings]

1 is a diagram showing a first embodiment of the present invention, and FIG. 2 is a diagram showing a second embodiment of the present invention. 10... Towing vehicle, 12... Transport vehicle, 14
... Engine, 16 ... Hydraulic device, 34 ... Pressure accumulator, 50 ... Hydraulic brake device, 54 ... Brake pedal switch (brake operation detection device), 58.
・Hydraulic brake device, 60... Master cylinder, 6
2... Working pressure chamber, 66... Solenoid switching valve.

Claims (1)

[Scope of Claims] 1. A braking system for a coupled vehicle comprising a towing vehicle equipped with an engine and a hydraulic system, and a transport vehicle coupled to the towing vehicle and towed by the same, comprising: The transport vehicle is equipped with an electromagnetic switching valve and a hydraulic brake system, and the pressure accumulator is capable of accumulating the hydraulic pressure of the cargo handling hydraulic system that is driven by the engine. Yes, the brake operation detection device can detect that the brakes of the towing vehicle have been activated, the hydraulic brake device of the transportation vehicle has a master cylinder for braking the transportation vehicle, and the electromagnetic switching valve has a The supply state of hydraulic pressure to the operating pressure chamber of the master cylinder can be switched, and the pressure accumulator of the towing vehicle and the electromagnetic switching valve of the transport vehicle are hydraulically connected by piping, and the brake operation detection device and the electromagnetic switching valve are connected hydraulically. Electrically connected by wiring, the electromagnetic switching valve discharges hydraulic pressure from the master cylinder's operating pressure chamber when the brake operation detection device does not detect brake operation, and when the brake operation detection device detects brake operation. A braking device for a coupled vehicle, characterized in that the braking device is configured to cause hydraulic pressure of a pressure accumulator to act on a working pressure chamber of a master cylinder. 2. A switching valve is installed in the middle of the piping on the transportation vehicle side that is connected to the master cylinder, and the switching valve is activated when a force is applied between the towing vehicle and the transportation vehicle in a direction that brings them closer together. 2. The connection according to claim 1, wherein the conduit is connected so as to be able to supply hydraulic pressure to the working pressure chamber of the master cylinder, and otherwise configured to discharge hydraulic pressure from the working pressure chamber of the master cylinder. Vehicle braking system.