JPH11278267A - Braking device - Google Patents

Abstract

(57) [Problem] To provide a braking device capable of shortening a braking distance in a case where traveling is performed by connecting hydraulic motors in series. When an emergency stop is performed, when an emergency stop switch is turned on, discharge of hydraulic oil from a pump P is regulated, and hydraulic pressure of hydraulic oil flowing out of hydraulic motors 6a and 6b becomes equal to or higher than a predetermined pressure. The hydraulic oil flowing through the motors 6a and 6b does not flow through the pump P but circulates through the relief valve 39b. Therefore, the flow rate decreases, and the hydraulic motors 6a, 6b
Is smaller than the rotation speed of the drive wheels, and a braking force is applied to the drive wheels by the hydraulic motors 6a and 6b. At this time, if the hydraulic motors 6a and 6b are connected in series and traveling, the hydraulic motors 6a and 6b are switched in parallel. For this reason, the motor capacity increases, the driving torque of the hydraulic motors 6a, 6b increases, and the braking force increases.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking device for a vehicle such as a track running vehicle that runs by driving wheels by a hydraulic motor.

[0002]

2. Description of the Related Art Such a vehicle has a road traveling wheel and a track traveling wheel. The vehicle travels using the road traveling wheel when traveling on the road, and travels using the track traveling wheel when traveling on the track. There is a track-and-land vehicle configured such that the track traveling is performed by driving the track traveling wheels by a hydraulic motor.

[0003] In the track traveling of a rail-land vehicle having such a configuration,
Generally, the traveling speed of the vehicle is controlled by variably controlling the discharge amount of a pump that is a drive source of a hydraulic motor. Furthermore, in the case where a plurality of hydraulic motors are provided, the flow rate is increased when the hydraulic motors are connected in series and the rotation speed of the hydraulic motors is increased as compared with the case where the hydraulic motors are connected in parallel. Speed mode can be switched.

The braking can be performed by controlling the supply of hydraulic oil to the hydraulic motor. In this case, when the hydraulic pressure of the hydraulic oil flowing out of the hydraulic motor becomes higher than a predetermined pressure, the hydraulic oil is relieved. For example, a relief valve to be provided is provided in parallel with the pump. In this case, when the discharge of the hydraulic oil from the pump is regulated, the hydraulic pressure of the hydraulic oil flowing out of the hydraulic motor becomes equal to or higher than a predetermined pressure, and the hydraulic oil flowing to the hydraulic motor does not flow to the pump but circulates through the relief valve. This allows
The relief valve reduces the area of the portion through which the oil flows, thereby reducing the flow rate. The rotational speed of the hydraulic motor becomes lower than the rotational speed of the wheels, and braking force is applied to the drive wheels by the hydraulic motor.

[0005]

Incidentally, the hydraulic motor has a smaller motor capacity and a smaller driving torque when connected in series than when connected in parallel. For this reason, in a vehicle in which the hydraulic motors can be connected in parallel or in series, there is a difference between the case where the hydraulic motors are connected in parallel and running and the case where the hydraulic motors are connected in series and running. There is a problem that the braking force is smaller and the braking distance is longer when the hydraulic motors are connected in series and traveling is performed than when they are connected in parallel and traveling.

The present invention has been made in view of such a problem, and provides a braking device capable of shortening a braking distance when a hydraulic motor is connected in series and running. It is an object.

[0007]

In order to achieve the above object, a braking device according to the present invention comprises a variable displacement pump,
And two or more hydraulic motors that are driven by hydraulic oil supplied from the pump to rotationally drive the wheels. When the vehicle travels, the traveling speed is controlled by variable control of the discharge amount of the pump. This is used for a vehicle in which the hydraulic motors can be connected in parallel or in series with each other, and is composed of braking operation means and connection change control means.

The braking operation means outputs a braking operation signal by an external operation, and the reconnection control means performs an operation of switching the hydraulic motors in parallel by the braking operation signal. For example, the braking operation signal is output. When the hydraulic motors are sometimes connected in series and running, the hydraulic motors are connected in parallel.

Specifically, the vehicle has, for example, a road running wheel and a track running wheel. The vehicle runs using the road running wheel when running on the road, and runs using the track running wheel when running on the track. The wheel driven by the hydraulic motor is a track-traveling wheel.

According to such a configuration, when the brake operating means is operated, the discharge of the hydraulic oil from the pump is regulated, the hydraulic pressure of the hydraulic oil flowing out of the hydraulic motor becomes equal to or higher than a predetermined pressure, and the hydraulic oil flowing to the hydraulic motor is increased. Circulates through the relief valve without flowing into the pump. For this reason, the area of the portion where oil flows by the relief valve is reduced, and the flow rate is reduced,
The rotation speed of the hydraulic motor becomes lower than the rotation speed of the wheels, and a braking force is applied to the drive wheels by the hydraulic motor.
At the same time, if the traveling is performed with the hydraulic motors connected in series, the hydraulic motors are switched in parallel. For this reason,
The motor capacity increases, the driving torque of the hydraulic motor increases, and the braking force increases.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows the configuration of a railway land vehicle 1 provided with the braking device of the present invention. The track-and-land vehicle 1 is configured with a truck as a base, and is capable of traveling on roads by tire wheels (wheels for road traveling) 3 attached to four places in front, rear, left and right of a vehicle body 2.

Iron wheels (track running wheels) 4 are further rotatably mounted at four positions on the front, rear, left and right sides of the vehicle body 2 on a steel wheel support member 5 supported by the vehicle body 2 so as to be swingable.
The iron wheel support member 5 is configured to swing by the expansion and contraction operation of the hydraulic cylinder 7, and the iron wheel 4 is projected downward or stored upward by the swing operation of the iron wheel support member 5. It has become. Rail-and-land vehicle 1 has iron wheels 4
The vehicle 2 with the rail overhanging the rail R (track) for railway
It can be put on the top and run on the track by the iron wheel 4.

In the center of the lower part of the vehicle body 2, a turntable 8 for moving the track-and-land vehicle 1 on the rail R is mounted. Further, on the vehicle body 2, a swivel 11 attached to the vehicle 2 so as to be horizontally rotatable, a boom 12 attached to the upper part of the swivel 11 so as to be able to undulate and expand and contract, and a boom 12 An aerial work apparatus 10 including an operator boarding work table 13 attached to the tip is provided.

Here, the track and land vehicle 1 travels on the track by driving the left and right iron wheels 4a and 4b on the front side. For this reason, the front left and right iron wheel support members 5a, 5
b, a hydraulic motor 6 for iron wheel drive as shown in FIG.
a and 6b are provided respectively. FIG. 4 shows a hydraulic pressure supply circuit to these hydraulic motors 6a and 6b.
Both hydraulic motors 6a and 6b are driven by hydraulic oil supplied from a pump P.

The pump P is a variable discharge type pump, and its displacement angle per rotation can be changed by changing its tilt angle by a servo mechanism (not shown). The pump P is a vehicle engine E which is a driving source of the tire wheels 3 during traveling on a road when traveling on a track.
ng is connected to a power take-off mechanism (not shown) for extracting an output of ng, and is driven by the vehicle engine Eng via the power take-off mechanism. Vehicle engine Eng
The engine speed is detected by an engine speed detector 21 (see FIG. 1), and the detection signal is input to the controller 20.

A switching valve 30 is provided in a hydraulic supply oil passage from the pump P to the hydraulic motors 6a and 6b, and both hydraulic motors 6a and 6b switch the pump P by switching the oil passage by the switching valve 30. Can be reconnected in parallel or in series.

That is, when the switching valve 30 is located at the lower position shown in FIG. 4, the hydraulic oil flowing from the pump P to the oil passage 31 is divided into two parts, one of which is the oil passage 32, the hydraulic motor 6a, the oil passage 33, The oil flows to the oil passage 35 via the switching valve 30 and the oil passage 34, and the other flows to the oil passage 35 via the oil passage 36, the switching valve 30, the oil passage 37, the hydraulic motor 6b, and the oil passage 38. Thus, the two hydraulic motors 6a and 6b are connected in parallel.

On the other hand, when the switching valve 30 is located at the upper position, the operating oil flowing from the pump P to the oil passage 31
2, hydraulic motor 6a, oil passage 33, switching valve 30, oil passage 3
7. The fluid flows into the oil passage 35 via the hydraulic motor 6b and the oil passage 38, and the two hydraulic motors 6a and 6b are connected in series.

An oil passage 40 connected between an oil passage 31 connected to the discharge port of the pump P and an oil passage 35 connected to the suction port is provided with an overload relief valve 39 including a check valve 39a and a relief valve 39b. ing. The overload relief valve 39 closes the oil passage 40 when the oil pressure in the hydraulic circuit is lower than a predetermined pressure, and the relief valve 39b opens the oil passage 40 when the oil pressure in the hydraulic circuit is higher than the predetermined pressure.

Further, in order to perform braking during track running, all of the front, rear, left and right iron wheels 4 are provided with disc brakes 4.
1 (see FIG. 3). As shown in FIG.
A hydraulic oil supply oil passage 42 is connected to the caliper 41a of the disc brake 41, and the hydraulic oil supply oil passage 42
Is supplied with hydraulic oil at all times. The oil passages 43 and 44 connected to the hydraulic oil supply oil passage 42 are provided with an electromagnetic proportional relief valve 45 and a shut-off valve 46, respectively.

The solenoid proportional relief valve 45 is designed to open completely when the solenoid is not energized, and to throttle the valve in response to an operation signal. Further, in a state where the valve is completely closed, when the oil pressure becomes equal to or higher than a predetermined pressure, the valve is opened to release the hydraulic oil. Shut-off valve 46
5 is arranged such that the oil passage 44 is closed when the solenoid is in the non-excited state and is at the upper movement position shown in FIG. 5, and is located at the lower movement position when the solenoid is in the excited state.

The disc brake 41 controls the hydraulic pressure of the hydraulic oil supply oil passage 42 by controlling the relief pressure of the supplied hydraulic oil by the electromagnetic proportional relief valve 45 and the shut-off valve 46, and the operation thereof is controlled. It is controlled.

Next, a description will be given of an apparatus configuration for controlling the running and braking of the vehicle by performing the operation control of these configurations. The running and braking operations during orbital running can be performed in the work table 13 when running while performing high-altitude work by the high-altitude working device 10, and can be performed in the driving cabin 9 when simply moving. Can be done.

First, the configuration of the work table 13 will be described.
The workbench 13 is provided with an upper traveling operation device 22 (see FIG. 2). The upper travel operating device 22 has a neutral position automatic return type lever 22a, and outputs a travel signal when the lever 22a is tilted. The travel signal includes speed information corresponding to the lever operation amount (tilt amount). When traveling at high speed, the lever operation amount may be increased. In addition, the upper traveling operation device 22
Outputs a braking signal when the lever 22a returns to the neutral position.

In addition, the work table 13 is provided with an engine speed setting device 23, a speed mode setting device 24a, and an emergency stop switch 25a (see FIG. 1). The engine speed setting device 23 is capable of switching between three types of engine speed, i.e., idling, medium speed, and high speed, and outputs a set engine speed setting signal. The speed mode setting device 24a can set the traveling speed mode switching between the low speed mode and the high speed mode, and outputs the set traveling speed mode signal. The emergency stop switch 25a outputs an emergency stop signal by operating the switch.

The signals output from the upper travel operating device 22, the engine speed setting device 23, the speed mode setting device 24a, and the emergency stop switch 25a are input to the controller 20 (see FIG. 1).

Hereinafter, these operations will be described. When idling rotation is set in the engine speed setting device 23, the controller 20 causes the vehicle engine Eng to idle. Then, based on the detection signal from the engine speed detector 21, the vehicle engine E
ng is detected to be idling, and the tilt angle of the pump P is fixed to zero by the servo mechanism. For this reason, in this case, even if the upper traveling operation device 22 is operated, the hydraulic oil is not discharged from the pump P, and the hydraulic motor 6
Since a and 6b do not rotate, the vehicle cannot run.

When running, the engine speed setting device 23 sets a medium speed or a high speed. In this case, the controller 20 rotates the vehicle engine Eng at the set speed of the input engine speed setting signal. When the lever 22a of the upper traveling operation device 22 is tilted in this state, the controller 20 changes the tilt angle of the pump P from zero to a maximum angle by the servo mechanism according to the input traveling signal. To change the displacement per revolution. For this reason, the discharge amount of the pump P increases according to the lever tilt amount, and the rotation speeds of the hydraulic motors 6a and 6b increase to increase the traveling speed.

At the time of traveling, the traveling speed mode can be switched by the speed mode setting device 24a. When the speed mode setting is switched to the low speed mode, a low speed mode signal is input to the controller 20, and an off signal is output from the controller 20 to the switching valve 30. As a result, the solenoid is de-energized, the switching valve 30 is located at the lower position shown in FIG. 4, and the two hydraulic motors 6a and 6b are connected in parallel.

In this case, the flow rate of the working oil is reduced by half and the rotation speed of the hydraulic motors 6a and 6b is reduced by half with respect to the case of the serial connection.
/ 2. On the other hand, the motor capacity is twice as large as that in the case of serial connection, and the driving torque of the hydraulic motors 6a and 6b is doubled.

When the speed mode setting is switched to the high speed mode, a high speed mode signal is input to the controller 20, and an ON signal is output from the controller 20 to the switching valve 30. As a result, the solenoid is excited, the switching valve 30 is located at the upper position, and the two hydraulic motors 6a and 6b are connected in series.

In this case, the flow rate of the working oil is doubled and the rotation speed of the hydraulic motors 6a and 6b is doubled as compared with the case of the parallel operation, so that the traveling speed is doubled in the low speed mode. On the other hand, the motor capacity is １ ／ of that in the case of parallel,
Since the driving torques of the hydraulic motors 6a and 6b are reduced to 1/2, the iron wheel driving torque is reduced to 1/2 in the low speed mode.

When the vehicle is running as described above and the engine speed detector 21 detects an engine speed higher than the idling speed,
An ON signal is output from the controller 20 to the shut-off valve 46. Therefore, the solenoid is excited, the shut-off valve 46 is moved to the lower position, and the oil passage 44 is opened. As a result, all the hydraulic oil supplied to the hydraulic oil supply oil passage 42 is relieved, the hydraulic pressure of the hydraulic oil supply oil passage 42 becomes zero, the operation of the disc brake is regulated, and the vehicle can run.

When performing normal braking, the operation of the upper traveling operation device 22 is stopped and the lever 22a is returned to the neutral position. In this case, the controller 20 makes the tilt angle of the pump P zero according to the traveling signal, and regulates the discharge of the hydraulic oil from the pump P. For this reason, the hydraulic pressure of the hydraulic oil flowing out of the hydraulic motors 6a, 6b increases, the relief valve 39b opens, and the hydraulic oil flowing to the hydraulic motors 6a, 6b is pump P
Does not flow through the oil passage 40 and circulates. In this case, the area of the portion where the oil flows is reduced by the relief valve 39b, and the flow rate is reduced. For this reason, the rotation speed of the hydraulic motors 6a and 6b becomes smaller than the rotation speed of the iron wheel 4, and braking force is applied to the drive wheels by the hydraulic motors 6a and 6b.

At the same time, a braking signal is output from the upper traveling operation device 22, and the controller 20 is controlled based on the braking signal.
Outputs an off signal to the shutoff valve 46. As a result, the solenoid is de-energized and the shut-off valve 4
6 is in the up position, and the oil passage 44 is closed, and an operation signal is output to the electromagnetic proportional relief valve 45 to close the valve. As a result, the hydraulic pressure in the hydraulic oil supply oil passage 42 increases, the disc brake 41 operates, and the iron wheel 4
Is given a braking force.

As described above, in the normal braking from the worktable 13 side, the braking force applied to the driving wheels by the hydraulic motors 6a and 6b by the regulation of the discharge of the hydraulic oil from the pump P and the braking force applied to the iron wheels 4 by the disc brake 41. The vehicle is braked by the applied braking force.

To perform an emergency stop, the emergency stop switch 25a is turned on. In this case, the controller 20
Rotates the engine Eng idling irrespective of the input engine speed setting signal. And
When the idling speed is detected from the detection signal of the engine speed detector 21, the tilt angle of the pump P is set to zero to restrict the discharge of the working oil from the pump P. at the same time,
Disc brake 4 in the same manner as in normal braking
1 is also activated.

Thus, as in the case of performing normal braking, the braking force applied to the driving wheels by the hydraulic motors 6a and 6b by the regulation of the discharge of the hydraulic oil from the pump P and the braking force applied to the iron wheels 4 by the disc brake. Thus, the vehicle is braked.

Here, the braking force applied to the drive wheels by the hydraulic motors 6a and 6b due to the regulation of the discharge of the hydraulic oil from the pump P differs between the low-speed mode and the high-speed mode. The braking force is such that when the two hydraulic motors 6a and 6b are connected in series, the motor capacity is doubled as compared with the case where the two hydraulic motors 6a and 6b are connected in parallel, and the driving torque of the two hydraulic motors 6a and 6b is doubled. Therefore, the speed in the low-speed mode is twice as large as that in the high-speed mode.

For this reason, the controller 20 controls the pump P
When the input of the speed mode signal is the high-speed mode and the vehicle is running in the high-speed mode, an off signal is output to the switching valve 30 and the hydraulic motors 6a, 6a, 6b are connected in parallel to obtain a larger braking force. Therefore, when an emergency stop is performed in a state where the vehicle is running in the high-speed mode, the braking distance is shortened by an increase in the braking force due to the reconnection of the two hydraulic motors 6a and 6b to parallel.

The reconnection of the hydraulic motors 6a and 6b to parallel may be performed not only when performing an emergency stop but also when performing normal braking.

Next, the configuration of the driving cabin 9 will be described. An accelerator pedal (not shown) for running tires during road running is used for running operation from inside the driving cabin 9. Since the pump P is driven by the engine Eng as described above, when the accelerator pedal is depressed, the engine speed changes, and the speed of the pump P changes.

Unlike the worktable 13 side, the operation cabin 9
Inside, a brake pedal device 26 is provided separately from the accelerator pedal. The brake pedal device 26 is provided with a stroke sensor on a brake pedal provided for braking during road running, and outputs a braking signal according to the amount of depression of the brake pedal. In addition, a speed mode setting device 24b similar to the work table 13 is provided in the driving cabin 9.
And an emergency stop switch 25b.

The signals output from the brake pedal device 26, the speed mode setting device 24b, and the emergency stop switch 25b are input to the controller 20 (see FIG. 1).

Hereinafter, these operations will be described. When the vehicle is not running and the accelerator pedal is not depressed, the engine Eng is idling. Therefore, the controller 20 detects that the vehicle engine Eng is idling by the detection signal from the engine speed detector 21 and makes the tilt angle of the pump P zero. For this reason, in this state, the hydraulic motors 6a and 6b do not rotate, and the vehicle does not run.

When traveling, the accelerator pedal is depressed as in the case of traveling on a road. In this case, the rotation speed of the pump P increases as the engine rotation speed of the engine Eng increases. At the same time, based on the detection signal from the engine speed detector 21, the controller 20 changes the tilt angle of the pump P according to the change in the engine speed until the engine speed reaches a predetermined speed. The displacement per one rotation is changed, and when the engine rotation speed becomes equal to or more than a predetermined rotation speed, the tilt angle of the pump P is fixed to the maximum, and the displacement per rotation is maximized.

As a result, when the accelerator pedal is depressed, the discharge amount of the pump P increases, the rotation speeds of the hydraulic motors 6a, 6b increase, and the traveling speed increases. In this case, the traveling speed mode can be switched by the speed mode setting device 24b in the same manner as the work table 13 side.

When performing normal braking, the driver releases his / her foot from the accelerator pedal and depresses the brake pedal as in the case of driving on a road. As a result, a braking signal is output from the brake pedal device 23, an off signal is output from the controller 20 to the shut-off valve 46, the solenoid is de-energized, the shut-off valve 46 is in the up position, and the oil passage 44 is closed. At the same time, an operation signal corresponding to the braking signal is output to the electromagnetic proportional relief valve 45, and the valve is throttled.

As a result, the hydraulic pressure in the hydraulic oil supply oil passage 42 increases, and the disc brake 41 operates according to the amount of depression to brake the iron wheels 4 to brake the vehicle. In this case, the engine Eng is rotating corresponding to the rotation of the iron wheel 4. The tilt angle of the pump P is an angle corresponding to the engine speed, and the discharge of hydraulic oil is not restricted.

When an emergency stop is performed, when the emergency stop switch 25b is turned on, the respective components are operated and the emergency stop can be performed in the same manner as in the case of performing the emergency stop from the workbench 13 side.

The above description has been made of an example in which the braking device of the present invention is applied to a railway vehicle. However, the braking device of the present invention performs not only the railway vehicle but also the hydraulic motor in parallel / series connection to change the speed. It can be used for all vehicles that can switch modes.

[0052]

As described above, according to the braking device of the present invention, when braking is performed by restricting the discharge of hydraulic oil from the pump, it is assumed that the hydraulic motor is connected in series and traveling is performed. Since the connection is switched in parallel, the motor capacity increases, the driving torque of the hydraulic motor increases, and the braking force increases. For this reason, the braking distance is shortened by an increase in the braking force.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a braking device of the present invention.

FIG. 2 is a side view showing a configuration of a railway land vehicle 1 having the braking device of FIG.

FIG. 3 is a rear view of the railway land vehicle 1 of FIG. 2;

FIG. 4 is a circuit diagram of a hydraulic pressure supply to hydraulic motors 6a and 6b.

FIG. 5 is a circuit diagram of a hydraulic pressure supply to a disc brake caliper 41a.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 track land vehicle 3 tire wheel (road running wheel) 4 iron wheel (track running wheel) 6a, 6b hydraulic motor 22 upper running operating device (braking operating means) 25a, 25b emergency stop switch (braking operating means) 26 brake pedal Device (braking operation means) 30 Switching valve (reconnection control means) 39b Relief valve P pump

 ────────────────────────────────────────────────── ─── Continuing from the front page (72) Inventor Katsunori Fukushima 5F West Wan Building, 58-1 Yashimacho, Takasaki City, Gunma Prefecture Astec Inc.

Claims (2)

[Claims] 1. A variable discharge type pump, and two or more hydraulic motors, which are driven by hydraulic oil supplied from the pump and rotationally drive wheels, are configured to reduce a discharge amount of the pump during traveling. A braking device for a vehicle configured to perform a traveling speed control by a variable control and capable of switching a parallel / series connection of the hydraulic motor with respect to the pump, and a braking operation unit that outputs a braking operation signal by an external operation. A braking control means for switching the hydraulic motors in parallel according to a signal from the braking operation signal. 2. The vehicle has a road running wheel and a track running wheel. The vehicle runs using the road running wheel when running on a road, and runs using the track running wheel when running on a track. The braking device according to claim 1, wherein a wheel driven by using the hydraulic motor is the track-traveling wheel.