JP4086957B2 - Braking device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a braking device for a vehicle such as a track traveling vehicle that travels by driving wheels by a hydraulic motor.
[0002]
[Prior art]
Such a vehicle has road traveling wheels and track traveling wheels, is configured to travel using road traveling wheels during road traveling, and is configured to travel using track traveling wheels during track traveling, There is a track-and-rail vehicle configured such that the track travel is performed by driving the track travel wheels with a hydraulic motor.
[0003]
In the track running of a track-and-rail vehicle having such a configuration, the running speed of the vehicle is controlled by variable control of the discharge amount of a pump that is a drive source of a hydraulic motor. In addition, when multiple hydraulic motors are provided, connecting the hydraulic motors in series will increase the flow rate and increase the rotational speed of the hydraulic motors when connected in parallel. The speed mode can be switched.
[0004]
The braking can be performed by controlling the supply of hydraulic oil to the hydraulic motor. In this case, a relief valve that relieves the hydraulic oil when the hydraulic pressure of the hydraulic oil flowing out from the hydraulic motor exceeds a predetermined pressure. Is provided in parallel with the pump, for example. In this case, when the discharge of the hydraulic oil from the pump is restricted, the hydraulic pressure of the hydraulic oil flowing out from the hydraulic motor becomes equal to or higher than a predetermined pressure, and the hydraulic oil flowing through the hydraulic motor flows through the relief valve and circulates without flowing through the pump. As a result, the area of the portion through which oil flows is reduced by the relief valve, the flow rate is reduced, the rotational speed of the hydraulic motor becomes smaller than the rotational speed of the wheels, and braking force is applied to the drive wheels by the hydraulic motor.
[0005]
[Problems to be solved by the invention]
By the way, 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 hydraulic motors can be connected in parallel or in series, the case where the hydraulic motor is connected in parallel and traveling is different from the case where traveling is performed in series connected, When traveling with hydraulic motors connected in series, the braking force is smaller and the braking distance becomes longer than when traveling with parallel motors connected.
[0006]
The present invention has been made in view of such problems, and an object of the present invention is to provide a braking device that can shorten the braking distance when the hydraulic motor is connected in series and traveling is performed. Yes.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a braking device according to the present invention includes a variable discharge hydraulic pump and a pair of left and right hydraulic motors that are driven to rotate by supply of hydraulic oil from the hydraulic pump. The pair of left and right hydraulic motors are configured to rotate the pair of left and right wheels so that the vehicle travels. During traveling, the pair of left and right hydraulic motors are rotationally driven by variable control of the discharge amount of the hydraulic pump. It is configured to control the traveling speed by controlling the speed, and the connection between the parallel connection that supplies the hydraulic oil from the hydraulic pump to the left and right hydraulic motors in parallel and the series connection that supplies the hydraulic oil in series is possible. It is used for a possible vehicle and is composed of a braking operation means and a connection control means.
[0008]
The braking operation means performs an operation of outputting a braking operation signal by an external operation to brake the wheels of the vehicle, and the reconnection control means operates with hydraulic oil from the hydraulic pump in a state where a pair of left and right hydraulic motors are connected in series. When the braking operation means is externally operated and a braking operation signal is output while the vehicle is running while being driven to rotate, the pair of left and right hydraulic motors are received in response to the braking operation signal. The connection is changed from the serial connection to the parallel connection while being rotated by receiving the supply of the hydraulic oil from the hydraulic pump .
[0009]
Specifically, the vehicle has, for example, a road traveling wheel and a track traveling wheel, travels using the road traveling wheel when traveling on the road, and travels using the track traveling wheel when traveling on the track. The wheel which consists of a track-rail vehicle comprised and is driven using a hydraulic motor is a wheel for track running.
[0010]
In a vehicle having such a configuration, generally, when the brake operation means is operated, the discharge of hydraulic oil from the hydraulic pump is suppressed, and the hydraulic oil is discharged from the hydraulic motor in a state where the hydraulic motor is driven by the wheels. The hydraulic pressure of the hydraulic oil flows from the hydraulic motor through the relief valve without flowing to the hydraulic pump. For this reason, driving the hydraulic motor requires a torque sufficient to discharge hydraulic oil having a relief pressure, and this torque acts as a torque for braking the rotation of the wheel, so that a braking force is applied to the wheel. Here, when a braking operation signal is output when the hydraulic motor is rotated in response to supply of hydraulic oil from a hydraulic pump in a serial connection state and the vehicle is traveling, the braking operation signal is received. As a result, the capacity of the pair of left and right hydraulic motors is doubled and the required driving torque of the hydraulic motor is doubled under the same relief pressure. Therefore, the braking force applied to the wheel is doubled, and a large braking force can be applied to the wheel from the hydraulic motor.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In FIG. 2, the structure of the track-and-rail vehicle 1 provided with the braking device of this invention is shown. This railroad vehicle 1 is configured with a truck as a base, and is capable of traveling on roads by tire wheels (road driving wheels) 3 attached to four places on the front, rear, left and right of the vehicle body 2.
[0012]
Iron wheels (orbital running wheels) 4 are further rotatably attached to iron wheel support members 5 that are swingably supported by the vehicle body 2 at four locations on the front and rear, left and right of the vehicle body 2. The iron ring support member 5 is oscillated by the expansion and contraction operation of the hydraulic cylinder 7, and the iron ring 4 is projected downward or stored upward by the oscillating operation of the iron ring support member 5. It has become. The track-and-rail vehicle 1 has a vehicle body 2 placed on a rail R (railway) for railroads with the iron wheel 4 overhanging, and can travel on the track by the iron wheel 4.
[0013]
A turntable 8 is mounted at the center of the lower part of the vehicle body 2 for transferring the railcar 1 on the rail R and moving it. Further, on the vehicle body 2, a swivel base 11 that is attached to the car body 2 so as to be horizontally turnable, a boom 12 that is attached to the upper part of the turntable 11 so as to be freely raised and retracted, and that can be freely expanded and contracted. An aerial work apparatus 10 is provided which includes an operator boarding work table 13 attached to the tip.
[0014]
Here, the track traveling of the track-and-rail vehicle 1 is performed by driving the left and right iron wheels 4a and 4b on the front side. For this reason, as shown in FIG. 3, hydraulic motors 6a and 6b for driving the iron wheels are respectively provided on the left and right iron wheel support members 5a and 5b on the front side. 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.
[0015]
The pump P is a variable discharge type pump, and its displacement volume can be changed per rotation by changing its tilt angle by a servo mechanism (not shown). This pump P is connected to a power take-off mechanism (not shown) that takes out the output of the vehicle engine Eng that is a drive source of the tire wheel 3 during road running during track running, and the vehicle engine Eng through the power take-off mechanism. Driven by. In the 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.
[0016]
A switching valve 30 is provided in the hydraulic supply oil path from the pump P to the hydraulic motors 6a and 6b, and both the hydraulic motors 6a and 6b are connected to the pump P by the switching of the oil path by the switching valve 30. It can be connected in parallel or in series.
[0017]
That is, when the switching valve 30 is located at the downward movement position shown in FIG. 4, the hydraulic oil flowing from the pump P to the oil passage 31 is divided into two, one of which is the oil passage 32, the hydraulic motor 6 a, the oil passage 33, and the switching valve 30. The oil flows to the oil passage 35 through the oil passage 34, and the other flows to the oil passage 35 through the oil passage 36, the switching valve 30, the oil passage 37, the hydraulic motor 6b, and the oil passage 38. The hydraulic motors 6a and 6b are connected in parallel.
[0018]
On the other hand, when the switching valve 30 is located at the upward movement position, the hydraulic oil flowing from the pump P to the oil passage 31 is transferred to the oil passage 32, the hydraulic motor 6a, the oil passage 33, the switching valve 30, the oil passage 37, the hydraulic motor 6b, and the oil. Both hydraulic motors 6a and 6b are connected in series by flowing to the oil passage 35 via the passage 38.
[0019]
An overload relief valve 39 including a check valve 39a and a relief valve 39b is provided in the oil passage 40 connected between the oil passage 31 connected to the discharge port of the pump P and the oil passage 35 connected to the suction port. The overload relief valve 39 closes the oil passage 40 when the hydraulic pressure in the hydraulic circuit is lower than a predetermined pressure, and the relief valve 39b opens the oil passage 40 when the hydraulic pressure in the hydraulic circuit is lower than the predetermined pressure.
[0020]
Further, in order to perform braking during track running, all of the front and rear, left and right iron wheels 4 are provided with disc brakes 41 (see FIG. 3). As shown in FIG. 5, a hydraulic oil supply oil passage 42 is connected to the caliper 41 a of the disc brake 41, and hydraulic oil is always supplied to the hydraulic oil supply oil passage 42. An oil proportional relief valve 45 and a shut-off valve 46 are provided in the oil passages 43 and 44 connected to the hydraulic oil supply oil passage 42, respectively.
[0021]
The electromagnetic proportional relief valve 45 opens the valve completely when the solenoid is in a non-excited state, and throttles the valve in accordance with the operation signal. When the valve is completely closed, when the hydraulic pressure exceeds a predetermined pressure, the valve is opened to relieve the hydraulic oil. The shut-off valve 46 is located at the upward movement position shown in FIG. 5 when the solenoid is in the non-excited state and closes the oil passage 44, and is located at the downward movement position in the excitation state and opens the oil passage 44.
[0022]
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 its operation is controlled. It is like that.
[0023]
Next, a description will be given of an apparatus configuration that performs operation control of these configurations and performs vehicle travel and braking control. The traveling and braking operation during the track traveling can be performed in the work table 13 when traveling while performing the high altitude work by the high altitude working device 10, and in the driving cabin 9 when simply moving, for example. Can be done.
[0024]
First, the configuration on the workbench 13 side will be described. The work table 13 is provided with an upper travel operation device 22 (see FIG. 2). The upper traveling operation device 22 has a neutral position automatic return type lever 22a. When the lever 22a is tilted, a traveling signal is output. This travel signal includes speed information corresponding to the lever operation amount (tilt amount), and the lever operation amount may be increased when traveling at high speed. The upper travel operation device 22 outputs a braking signal in a state where the lever 22a has returned to the neutral position.
[0025]
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 can switch and set three kinds of engine speeds of 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 when the switch is operated.
[0026]
The signals output from the upper traveling operation 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).
[0027]
Hereinafter, these operations will be described. When the idling rotation is set in the engine speed setting device 23, the controller 20 causes the vehicle engine Eng to perform idling rotation. Then, it is detected from the detection signal from the engine speed detector 21 that the vehicle engine Eng is 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 travel operation device 22 is operated, the hydraulic oil is not discharged from the pump P, and the hydraulic motors 6a and 6b do not rotate, so that the vehicle cannot travel. Yes.
[0028]
When traveling, the engine speed setting device 23 sets medium speed or high speed rotation. In this case, the controller 20 rotates the vehicle engine Eng at the set rotational speed of the input engine rotational speed setting signal. In this state, when the lever 22a of the upper travel operation device 22 is tilted, the controller 20 causes the servo mechanism to change the tilt angle of the pump P between zero and a maximum angle according to the input travel signal. Change the displacement volume per revolution. For this reason, the discharge amount of the pump P increases according to the lever tilt amount, the rotational speed of the hydraulic motors 6a and 6b increases, and the traveling speed increases.
[0029]
Further, during this 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 and the switching valve 30 is positioned at the downward movement position shown in FIG. 4, and both hydraulic motors 6a and 6b are connected in parallel.
[0030]
In this case, the flow rate of the hydraulic oil is halved and the rotational speed of the hydraulic motors 6a and 6b is halved compared to the case of the series, so that the traveling speed is ½ that of the high speed mode. On the other hand, the motor capacity is double that in series and the driving torque of the hydraulic motors 6a and 6b is doubled, so that the wheel driving torque is double that in the high-speed mode.
[0031]
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 energized, the switching valve 30 is positioned in the up position, and the hydraulic motors 6a and 6b are connected in series.
[0032]
In this case, since the flow rate of the hydraulic oil is doubled and the rotational speeds of the hydraulic motors 6a and 6b are doubled as compared with the parallel case, the traveling speed is twice that in the low speed mode. On the other hand, since the motor capacity is ½ when the motor capacity is parallel, and the driving torque of the hydraulic motors 6a and 6b is ½, the iron wheel driving torque is ½ when the low speed mode.
[0033]
In the state where traveling is performed in this way and the engine speed detector 21 detects an engine speed greater than the idling speed, an ON signal is output from the controller 20 to the shutoff valve 46. For this reason, the solenoid is energized and the shut-off valve 46 is in the downward movement position, and the oil passage 44 is opened. As a result, all of 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 restricted, and the vehicle can run.
[0034]
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 controls the discharge of the hydraulic oil from the pump P by setting the tilt angle of the pump P to zero according to the travel signal. For this reason, the hydraulic pressure of the hydraulic oil flowing out from the hydraulic motors 6a and 6b increases, the relief valve 39b opens, and the hydraulic oil flowing through the hydraulic motors 6a and 6b flows through the oil passage 40 and circulates without flowing through the pump P. In this case, the relief valve 39b reduces the area of the portion through which the oil flows, thereby reducing the flow rate. For this reason, the rotational speed of the hydraulic motors 6a and 6b becomes lower than the rotational speed of the iron wheel 4, and braking force is applied to the drive wheels by the hydraulic motors 6a and 6b.
[0035]
At the same time, a braking signal is output from the upper traveling operation device 22, and an off signal is output from the controller 20 to the shutoff valve 46 based on this braking signal. As a result, the solenoid is de-energized, the shut-off valve 46 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, and the valve is closed. As a result, the hydraulic pressure of the hydraulic oil supply oil passage 42 is increased, the disc brake 41 is operated, and a braking force is applied to the iron wheel 4.
[0036]
As described above, in normal braking from the work table 13 side, the braking force applied to the drive wheels by the hydraulic motors 6 a and 6 b and the braking force applied to the iron wheels 4 by the disc brake 41 according to the discharge restriction of the hydraulic oil from the pump P. Thus, the vehicle is braked.
[0037]
When performing an emergency stop, the emergency stop switch 25a is turned on. In this case, the controller 20 causes the engine Eng to rotate idling regardless of the input engine speed setting signal. Then, it is detected from the detection signal of the engine speed detector 21 that the idling speed has been reached, and the tilt angle of the pump P is made zero to restrict the discharge of hydraulic oil from the pump P. At the same time, the disc brake 41 is also operated in the same manner as when performing normal braking.
[0038]
Thus, as in the case of normal braking, the vehicle is driven by the braking force applied to the drive wheels by the hydraulic motors 6a and 6b and the braking force applied to the iron wheels 4 by the disc brakes by restricting the discharge of hydraulic oil from the pump P. Braking is performed.
[0039]
Here, the braking force applied to the drive wheels by the hydraulic motors 6a and 6b due to the discharge restriction of the hydraulic oil from the pump P is different between the low speed mode and the high speed mode. As for this braking force, when both hydraulic motors 6a and 6b are connected in series, the motor capacity is doubled, and the driving torque of both hydraulic motors 6a and 6b is doubled. Therefore, the low speed mode is twice as large as the high speed mode.
[0040]
For this reason, when the controller 20 regulates the discharge of hydraulic oil from the pump P, if the input speed mode signal becomes the high speed mode and the vehicle is traveling in the high speed mode, the controller 20 turns off the switching valve 30. And the hydraulic motors 6a and 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 traveling in the high speed mode, the braking distance is shortened by an amount corresponding to the increase in the braking force due to the switching of both the hydraulic motors 6a and 6b in parallel.
[0041]
Note that the switching of the hydraulic motors 6a and 6b in parallel may be performed not only when performing an emergency stop but also when performing normal braking.
[0042]
Next, the configuration on the operation cabin 9 side will be described. For the traveling operation from the inside of the driving cabin 9, an accelerator pedal (not shown) for tire traveling during road traveling is used. Since the pump P is driven by the engine Eng as described above, the engine speed changes when the accelerator pedal is depressed, and the pump P speed changes.
[0043]
Unlike the work bench 13 side, a brake pedal device 26 is provided in the driving cabin 9 separately from the accelerator pedal. The brake pedal device 26 is provided with a stroke sensor in a brake pedal provided for braking when traveling on the road, and outputs a braking signal according to the depression amount of the brake pedal. In addition, a speed mode setting device 24b and an emergency stop switch 25b similar to those on the work table 13 side are provided in the operation cabin 9.
[0044]
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).
[0045]
Hereinafter, these operations will be described. When the vehicle is not running and the accelerator pedal is not depressed, the engine Eng is idling. For this reason, the controller 20 detects that the vehicle engine Eng is rotating idling based on the detection signal from the engine speed detector 21, and makes the tilt angle of the pump P zero. Therefore, in this state, the hydraulic motors 6a and 6b do not rotate and the vehicle does not travel.
[0046]
When traveling, the accelerator pedal is depressed in the same manner as when traveling on the road. In this case, the rotational speed of the pump P increases as the engine rotational speed of the engine Eng increases. At the same time, the controller 20 changes the tilt angle of the pump P in accordance with the change in the engine speed until the engine speed reaches a predetermined speed based on the detection signal from the engine speed detector 21. When the displacement volume per rotation is changed and the engine rotation speed becomes equal to or higher than the predetermined rotation speed, the tilt angle of the pump P is fixed to the maximum, and the displacement volume per rotation is maximized.
[0047]
As a result, when the accelerator pedal is depressed, the discharge amount of the pump P increases, the rotational speed of the hydraulic motors 6a and 6b increases, and the traveling speed increases. In this case as well, the traveling speed mode can be switched by the speed mode setting device 24b in the same manner as the work table 13 side.
[0048]
When performing normal braking, the foot is released from the accelerator pedal and the brake pedal is stepped on, as in road driving. As a result, a brake 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 moved to 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.
[0049]
As a result, the hydraulic pressure of the hydraulic oil supply oil passage 42 is increased, and the disc brake 41 is actuated according to the depression amount to brake the iron wheel 4 and the vehicle is braked. In this case, the engine Eng rotates in response to the rotation of the iron wheel 4. The pump P has an inclination angle corresponding to the engine speed, and the discharge of hydraulic oil is not restricted.
[0050]
In the case of performing an emergency stop, when the emergency stop switch 25b is turned on, each component can be operated in the same manner as in the case of performing an emergency stop from the workbench 13 side to perform an emergency stop.
[0051]
The example in the case where the braking device of the present invention is used for a track-and-rail vehicle has been described above. It can be used for all possible vehicles.
[0052]
【The invention's effect】
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, if the hydraulic motor is connected in series and traveling is performed, the hydraulic oil is connected in parallel. Therefore, 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 as the braking force increases.
[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 track-and-rail vehicle 1 having the braking device of FIG.
3 is a rear view of the track-and-rail vehicle 1 of FIG.
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 the disc brake caliper 41a.
[Explanation of symbols]
1 Railroad vehicle 3 Tire wheel (Wheel for road driving)
4 Iron wheels (wheels for track running)
6a, 6b Hydraulic motor 22 Upper travel operation device (braking operation means)
25a, 25b Emergency stop switch (braking operation means)
26 Brake pedal device (braking operation means)
30 switching valve (connection control means)
39b Relief valve P Pump

Claims (2)

A variable discharge amount type hydraulic pump, and a pair of left and right hydraulic motors that are driven to rotate by supply of hydraulic oil from the hydraulic pump, and the pair of left and right hydraulic motors drives the pair of left and right wheels to rotate. The vehicle is configured to travel, and during traveling, the rotational speed of the pair of left and right hydraulic motors is controlled by variable control of the discharge amount of the hydraulic pump to perform traveling speed control. In a vehicle capable of switching between a parallel connection for supplying hydraulic oil from the hydraulic pump in parallel to the pair of left and right hydraulic motors and a serial connection for supplying in series ,
A braking operation means for outputting a braking operation signal by an external operation and performing an operation of braking the wheels of the vehicle ;
When the braking operation means is externally operated and a braking operation signal is output when the hydraulic motor is connected in series and is rotated by receiving hydraulic oil supplied from the hydraulic pump and the vehicle is running The switching control means for switching the series connection from the parallel connection to the parallel connection in a state where the pair of left and right hydraulic motors are supplied with the hydraulic oil from the hydraulic pump and are rotationally driven in response to the braking operation signal. A braking device characterized by comprising: The vehicle has a road traveling wheel and a track traveling wheel, travels using the road traveling wheel when traveling on a road, and travels using the track traveling wheel when traveling on a track. Consist of cars,
The braking device according to claim 1, wherein a wheel driven by using the hydraulic motor is the track traveling wheel.

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