JP2000296723A - Travel control device for hydraulically driven vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a travel control device which controls the supply of hydraulic oil from one hydraulic pump to right and left hydraulic motors and secures straight running performance. SOLUTION: This control device controls the supply of hydraulic oil to right and left hydraulic motors for travel driving 23, 22 by means of a supply control valve 55 so as to perform travel control and steering control of a hydraulically driven vehicle. A communicating oil line connecting right and left supply oil lines which supply the hydraulic oil from the supply control valve 55 to the right and left hydraulic motors 23, 22, respectively, and an open/close control valve 57 which performs open/close control of the communicating oil line are provided, and with the operation of operating levers 32, 31, the supply of the hydraulic oil to each of the right and left hydraulic motors 23, 22 is independently controllable. When the difference between the amounts of hydraulic oil supplied to the right and left hydraulic motors 23, 22, each amount which is set by an operation of the operating levers 32, 31, is equal to or smaller than a prescribed value, the open/close control valve 57 is controlled to so as to open, while when the difference exceeds the prescribed value, the open/close control valve 57 is controlled so as to close.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a vehicle having running means (for example, crawlers or wheels) on the left and right sides of a vehicle body.
The present invention relates to a travel control device of a hydraulically driven vehicle configured to travel by driving these left and right traveling means by left and right hydraulic motors, respectively.

[0002]

2. Description of the Related Art Such a hydraulically driven vehicle has been known in the past and has been put to practical use as various vehicles, for example, self-propelled aerial work vehicles. Such a hydraulically driven vehicle,
The vehicle can be steered by controlling the supply of hydraulic oil to the left and right hydraulic motors and changing the drive speed of the left and right crawlers or wheels (running means). This method is a steering method that is particularly effective for a crawler traveling vehicle, and has conventionally been generally used for crawler traveling vehicles. Also,
Even a wheel-driven vehicle has the advantage that a steering mechanism generally used to steer the front wheels of an automobile is unnecessary and that a steering device can be easily configured. It is used in driving vehicles.

[0003]

A hydraulically driven vehicle of the type in which the right and left hydraulic motors independently drive and steer the crawler or the wheels by independently controlling the traveling of the crawler or the wheels only by controlling the hydraulic pressure supply to the left and right hydraulic motors. Control and steering control can be performed simultaneously and there is an advantage that the configuration of the drive system is simple, but there is a problem that it is difficult to perform drive control by synchronizing the left and right hydraulic motors. This is because, for example, the drive speed of the hydraulic motor is affected by the load applied to the hydraulic motor, the volume efficiency is affected by leakage of hydraulic oil from the hydraulic pump to the hydraulic motor, etc. This is due to the influence of the performance and accuracy of the valve. For this reason, for example, even if it is going to make the vehicle go straight by rotating the left and right motors
There is a problem that there is a slight difference between the left and right rotations and it is difficult to go straight.

[0004] In particular, the problem described above is great in a hydraulically driven vehicle in which hydraulic oil from one hydraulic pump is distributed by a left and right hydraulic motor by a supply control valve to perform drive control. For this reason, there has been used a hydraulically driven vehicle in which two hydraulic pumps are provided and hydraulic oil is independently supplied from each hydraulic pump to the left and right hydraulic motors to improve the straightness. However, in this case, even if the straightness can be improved to some extent, two hydraulic pumps and two supply control valves are required, and there is a problem that the device configuration becomes large and control is likely to be complicated.

The present invention has been made in view of such a problem.
It is an object of the present invention to provide a travel control device for a hydraulically driven vehicle that uses a form in which hydraulic oil supply control is performed from one hydraulic pump to left and right hydraulic motors, and that can ensure straightness.

[0006]

In order to achieve the above object, according to the present invention, running means (for example, crawlers, wheels, etc.) are provided on the left and right sides of the vehicle body, and the left and right running means are moved to the left and right. The hydraulic drive vehicle is driven by a hydraulic motor and a right hydraulic motor, and the hydraulic pump is controlled by a supply control valve to supply hydraulic oil from the hydraulic pump to the left and right hydraulic motors to perform travel control and steering control. Be composed. Further, a communication oil path is provided for connecting a left supply oil path for supplying hydraulic oil to the left hydraulic motor from the supply control valve and a right supply oil path for supplying hydraulic oil to the right hydraulic motor, and the communication oil path is opened and closed. An opening / closing control valve for performing control, operating means operated for controlling the operation of the supply control valve, and a hydraulic oil supply amount setting signal for the left hydraulic motor and a right hydraulic motor for the supply control valve in response to the operation of the operating means And a control means for independently controlling the supply of the hydraulic oil to the left and right hydraulic motors. When the difference between the hydraulic oil supply amount setting signal values of the left and right hydraulic motors is equal to or smaller than a predetermined value, the control means opens the opening / closing control valve, and the difference between the hydraulic oil supply amount setting signal values becomes a predetermined value. Is exceeded, control to close the open / close control valve is performed.

The supply control valve and the opening / closing control valve are constituted by electromagnetic control valves, and the operating means are provided with left and right operating levers. The control means controls the operating oil supply amount in accordance with the operation of these left and right operating levers. To the supply control valve to control the operation of the supply control valve. In this case, when the operation amounts of the left and right operation levers are substantially equal and the difference between the hydraulic oil supply amount setting signal values of the left and right hydraulic motors is equal to or less than a predetermined value, the opening / closing control valve is opened to set the hydraulic oil supply amount. When the difference between the signal values exceeds a predetermined value, control is performed to close the open / close control valve.

[0008] According to the traveling control device having such a configuration,
The operating means can set the rotational speeds of the left and right hydraulic motors to be equal (that is, to equalize the amounts of hydraulic oil supplied to the left and right hydraulic motors) and cause the vehicle to travel straight. At this time, when the difference between the hydraulic oil supply amount setting signal values of the left and right hydraulic motors is small (when the difference is equal to or less than a predetermined value), it is determined that the vehicle is going to travel straight by the operating means, and the opening / closing control valve is set. The control is performed such that the oil supply paths to the left and right hydraulic motors are communicated with each other to open and the left and right hydraulic motors are synchronously rotated to maintain straightness. Then, when the difference between the hydraulic oil supply amount setting signal values of the left and right hydraulic motors becomes large, it is determined that the steering control is to be performed by changing the speed of the left and right traveling means by the operating means, and the opening / closing control valve is determined. And the hydraulic oil supply to the left and right hydraulic motors is independently controlled. As a result, the steering performance can be secured as before, and the straightness can be further improved.

However, if the load applied to the left and right hydraulic motors is different during the control for maintaining the straight traveling property by opening the open / close control valve, the larger load is applied because the open / close control valve is opened. As the oil amount of the hydraulic motor decreases, the oil amount of the hydraulic motor having a smaller load increases, and the straightness may be reduced. For this reason, a rotation oil amount detecting means for detecting the rotation speed or the supply oil amount of the left and right hydraulic motors is provided, and the left and right hydraulic motors detected by the rotation oil amount detection means in a state where the open / close control valve is opened. When the difference between the rotation speed and the supply oil amount becomes equal to or more than the second predetermined value, the opening / closing control valve is closed or the communication oil passage is narrowed, and the difference between the rotation speed and the supply oil amount is less than the second predetermined value. The control of the operation of the supply control valve may be performed in such a manner.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an aerial work vehicle 10 including a travel control device according to the present invention. The aerial work vehicle 10 is configured based on a crawler traveling device 11. Crawler traveling device 11
Is a crawler belt (running means) arranged on both the left and right sides
12 and 13 and hydraulic motors (left hydraulic motor 22 and right hydraulic motor 23) for driving the respective crawler belts 12 and 13. In the crawler traveling device 11, each of the crawler belts 12, 13 is driven in a direction to cause the vehicle body to travel forward by the forward rotation of the hydraulic motors 22, 23. In addition, each hydraulic motor 22,
23 rotates in reverse, each crawler belt 1
Reference numerals 2 and 13 are driven in a direction in which the vehicle body travels backward.

A swivel 15 is mounted on the crawler traveling device 11 so as to be horizontally swivelable.
Further, a boom 16 which is telescopically configured to be extendable and retractable is attached to the upper portion of the swivel base 15. A work table 17 is horizontally mounted on the tip of the boom 16, and a traveling operation device (operation means) 30 and other operation devices are mounted on the upper inside of the work table 17.

An operator can board the work table 17 of the aerial work vehicle 10 configured as described above, and the operator can operate the crawler traveling device 11 by operating each operation device.
The operation of the boom 16 and the like can be controlled, and the user can move to any height. In the aerial work vehicle 10, the operation of the crawler traveling device 11 by the traveling operation device 30 is controlled through the traveling control device according to the present invention. Less than,
The hydraulic travel control device will be described with reference to FIG.

The traveling control device controls a hydraulic pump 52 driven by an engine 51 and a hydraulic oil supplied from the hydraulic pump 51 via a discharge oil passage 41 to the left and right hydraulic motors 22 and 23. And a supply control valve 55 for performing the operation. The supply control valve 55 and the left hydraulic motor 22 are connected via oil passages 42a and 42b, and the supply control valve 55 and the right hydraulic motor 23 are connected to the oil passage 43.
a, 43b.

When hydraulic oil is supplied from the supply control valve 55 to the left hydraulic motor 22 via the oil passage 42a, the left hydraulic motor 22 is driven forward (forward rotation). The hydraulic oil that drives the left hydraulic motor 22 is supplied to the oil passage 42b.
And from the supply control valve 55 through the return oil passage 44 to the tank. Conversely, when hydraulic oil is supplied from the supply control valve 55 to the left hydraulic motor 22 via the oil passage 42b, the left hydraulic motor 22 is driven backward (reverse drive). Similarly, when hydraulic oil is supplied from the supply control valve 55 to the right hydraulic motor 23 via the oil passage 43a, it is driven forward, and hydraulic oil is supplied to the right hydraulic motor 23 via the oil passage 43b. Then, it is driven to the reverse side.

When the supply direction of the hydraulic oil from the supply control valve 55 to the left and right hydraulic motors 22 and 23 is controlled as described above, the rotation directions of the left and right hydraulic motors 22 and 23 can be controlled, and the forward and backward traveling drive control can be performed. Is possible. Further, the supply control valve 55 is connected to the left and right hydraulic motors 22 and 23.
The amounts of oil supplied to the motors can be controlled independently of each other, whereby the rotational speeds of the left and right hydraulic motors 22 and 23 can be controlled to perform steering control. In order to control the operation of the supply control valve 55, a controller (control means)
35 and the above-mentioned traveling operation device 30 are provided.

First, the supply control valve 55 is an electromagnetically controlled valve, and its operation is controlled based on an operation control signal sent from the controller 35 via a signal line 36. As shown in FIG. 2, the traveling operation device 30 includes a neutral automatic return type left operation lever 31 and a right operation lever 32.
When each of the operation levers 31 and 32 is tilted forward and backward, an operation signal (a hydraulic oil supply amount setting signal) corresponding to the tilt operation direction is output to the controller 35. For example, when the operation levers 31 and 32 are tilted forward, an operation signal in the forward direction is output, and this signal becomes a larger operation signal as the tilt angle increases in accordance with the tilt angle. Similarly, when the operation levers 31 and 32 are tilted backward,
A drive signal in the reverse direction corresponding to the tilt angle is output.

When the controller 35 receives an operation signal corresponding to the operation of the operation levers 31 and 32, the controller 35 transmits an operation control signal (operation oil supply amount setting signal) corresponding to the operation signal to a supply control valve of an electromagnetic control type. Output to 55. Then, the supply control valve 55 is operated based on the operation control signal to control the supply of the hydraulic oil. With such control, for example, when the left operation lever 31 is tilted forward, hydraulic oil is supplied from the supply control valve 55 to the left hydraulic motor 22 via the oil passage 42a, and the left hydraulic motor 2
2 is driven in the forward direction. At this time, the supplied oil amount corresponds to the tilt operation angle of the left operation lever 31. As the tilt operation angle is larger, the supplied oil amount increases and the driving speed of the left hydraulic motor 22 also increases.

As a result, when the left and right operating levers 31 and 32 are both tilted forward by the same tilt angle, the left and right hydraulic motors 31 and 32 are controlled to be driven forward at the same speed. 10 is driven straight forward. When the tilt angles of the left and right operation levers 31 and 32 are made different, the rotational speeds of the left and right hydraulic motors 31 and 32 are different, and the aerial work vehicle 10 can be steered.

By the way, the left and right operation levers 3
When the aerial work vehicle 10 is driven straight forward by tilting both the front and rear wheels 1 and 32 by the same tilt angle, variations in the amount of hydraulic oil supplied by the supply control valve 55, etc.
There may be a difference between the rotational speeds of the left and right hydraulic motors 31, 32, and the traveling direction may gradually deviate from the straight traveling direction. In particular,
Here, such control is likely to occur because control is performed to distribute the hydraulic oil discharged from one pump 51 by the supply control valve 55.

For this reason, the traveling control device shown in FIG. 2 is provided with an opening / closing control valve 57, and the opening / closing control valve 57 connects the oil passage 42a and the oil passage 43a to each other.
a, 45b and the oil passage 42
b and the oil passage 43b can be communicated via the communication oil passages 46a and 46b. The opening / closing control valve 57 is an electromagnetically controlled valve, and its operation is controlled based on an opening / closing control signal sent from the controller 35 via the signal line 37.

The operation control of the opening / closing control valve 57 will be described below. For this control, the controller 35 compares operation signals (operating oil supply amount setting signals) from the left and right operation levers 31 and 32 and determines whether or not both operation signals are in the same direction (the same in forward and reverse directions). sex)
And a difference between signal values is detected. When the two operation signals are in the same direction and the difference between the signal values is small (when the difference is within a predetermined value: the predetermined value is set to a very small value), the controller 35 sets the open / close control valve 57
The valve 57 is moved to the left in FIG. 2 to communicate the oil passage 42a and the oil passage 43a via the communication oil passages 45a and 45b, and
2b and the oil passage 43b are communicated via the communication oil passages 46a and 46b.

As a result, even if there is a difference in the amount of oil to be supplied from the supply control valve 55 to the left and right hydraulic motors 31, 32, the oil amount is distributed through the communicating oil passages 45a, 45b, 46a, 46b. Adjusted left and right hydraulic motors 31,3
The amount of oil supplied to 2 becomes equal. As a result, the aerial work vehicle 1
The straightness of 0 is improved.

As can be seen from the above description, when the left and right operating levers 31 and 32 are operated in the same direction by substantially the same tilt angle, the open / close control valve 57 is opened,
The straightness of the vehicle is improved. On the other hand, the left and right operation levers 3
When the tilt angles of the operating levers 31 and 32 are different from each other by a predetermined angle or more, the opening / closing control valve 57 is closed, and the left and right hydraulic motors 22 and 2 are driven at a speed corresponding to the operating tilt angles of the operating levers 31 and 32.
3 is driven, and steering control of the vehicle can be performed. Here, the operation of the opening / closing control valve 57 is controlled based on the difference between the operation signals input to the controller 35 in response to the operation of the left and right operation levers 31 and 32. The operation of the open / close control valve 57 may be controlled based on the difference between the output operation control signals.

In the case where the opening / closing control valve 57 is opened to perform the control for maintaining the straight running property, if the loads applied to the left and right hydraulic motors 22 and 23 are different, the opening / closing control valve 57 is opened. In addition, the oil amount of the hydraulic motor having a larger load decreases, and the oil amount of the hydraulic motor having a smaller load increases. Therefore, a rotation oil amount detection sensor (not shown) for detecting the rotation speed or the supply oil amount of the left and right hydraulic motors 22 and 23 is provided, and the opening and closing control valve 57 is opened as described above. When the difference between the rotation speeds of the left and right hydraulic motors 22 and 23 or the supply oil amount detected by the rotation oil amount detection sensor is equal to or greater than a second predetermined value, control for closing the opening / closing control valve 57 or opening / closing control valve The control for reducing the opening degree of the communication oil passage is performed by 57.

However, this only returns to the original state (the state before the opening and closing control valve 57 is opened). Therefore, the control for closing the opening and closing control valve 57 or the communication oil passage by the opening and closing control valve 57 as described above. When the control for reducing the opening degree is performed, the difference between the rotation speeds or the supply oil amounts of the left and right hydraulic motors 22, 23 detected by the rotation oil amount detection sensor at the same time is set to be less than the second predetermined value. The operation of the supply control valve 57 is controlled to ensure straight running.

[0026]

As described above, when the traveling control device of the present invention is used, when the operating means sets the rotational speeds of the left and right hydraulic motors to be equal and the vehicle travels straight, the opening / closing operation is performed. Since the control valve is opened and the supply oil passages to the left and right hydraulic motors are communicated and the left and right hydraulic motors are synchronized to perform control to maintain straightness, the operation for straight running becomes easy and straight running performance is improved. Is improved. When the rotation speeds of the left and right hydraulic motors are made different, the open / close control valve is closed and the vehicle can turn in accordance with the operation. As a result, it is possible to improve the straightness while maintaining the steering performance. Can be.

However, if the difference between the rotation speeds of the left and right hydraulic motors or the supply oil amount detected by the rotation oil amount detection means becomes greater than or equal to the second predetermined value while the opening / closing control valve is open, The control for closing the control valve or the control for narrowing the communication oil passage is performed, and the operation control of the supply control valve for reducing the difference in the number of revolutions or the amount of supplied oil to less than the second predetermined value is performed. Accordingly, in the case where the opening / closing control valve is opened to perform the control for maintaining the straightness, the straightness can be ensured even when the loads applied to the left and right hydraulic motors are different.

[Brief description of the drawings]

FIG. 1 is a perspective view of an aerial work vehicle (crawler type hydraulically driven vehicle) provided with a travel control device according to the present invention.

FIG. 2 is a hydraulic circuit diagram showing a hydraulic drive system having the traveling control device.

[Explanation of symbols]

 REFERENCE SIGNS LIST 10 aerial work vehicle 11 crawler traveling device 12, 13 crawler belt 22, 23 hydraulic motor 30 traveling operation device 31, 32 operating lever 35 controller 52 hydraulic pump 55 supply control valve 57 open / close control valve

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masato Ogawa 1152 Yamashita, Ryoji, Ryoji, Ageo City, Saitama Prefecture Inside Aichi Corporation Ageo Works (72) Inventor Masanobu Saito 1152, Ryoke, Ryuji, Ryoke, Ageo City, Saitama Prefecture No.10 Aichi Corporation Ageo Works (72) Inventor Motoaki Suda 1152 Yamashita, Ryoji, Ageo City, Saitama Prefecture Aichi Corporation Ageo Works F term (reference) 3D042 AA02 AA03 AA06 AB07 AB10 BA02 BA07 BA19 BA20 BC02 BC08 BC09 BC14 BC17 BC18 BD04 BD08 BD09

Claims (4)

[Claims] 1. A left and right running means disposed on the left and right sides of a vehicle body, a left hydraulic motor for driving the left running means, a right hydraulic motor for driving the right running means, A hydraulic pump that supplies drive hydraulic oil to the right hydraulic motor, a supply control valve that controls supply of hydraulic oil from the hydraulic pump to the left and right hydraulic motors, and a supply control valve that controls supply of the hydraulic oil from the supply control valve to the left hydraulic motor. A communication oil path connecting a left supply oil path for supplying hydraulic oil and a right supply oil path for supplying hydraulic oil to the right hydraulic motor; an open / close control valve for controlling opening / closing of the communication oil path; Operating means operated to control the operation of the valve; and a hydraulic oil supply amount setting signal for the left hydraulic motor and the right side signal to the supply control valve in response to the operation of the operating means. Control means for sending a hydraulic oil supply amount setting signal for the pressure motor and independently controlling hydraulic oil supply control to the left and right hydraulic motors, wherein the control means When the difference between the hydraulic oil supply amount setting signal values is equal to or less than a predetermined value, the opening and closing control valve is opened, and when the difference between the hydraulic oil supply amount setting signal values exceeds a predetermined value, the opening and closing control valve is closed. A travel control device for a hydraulically driven vehicle, comprising: 2. The control valve according to claim 1, wherein the supply control valve and the opening / closing control valve are electromagnetic control valves, and the operating means has left and right operating levers. The control means is configured to send an operating oil supply amount setting signal to the supply control valve to control the operation of the supply control valve. When the difference between the hydraulic oil supply amount setting signal values of the motor is equal to or less than a predetermined value, the opening / closing control valve is opened, and when the difference between the hydraulic oil supply amount setting signal values exceeds a predetermined value, the opening / closing control valve is closed. The travel control device for a hydraulically driven vehicle according to claim 1, wherein the control is performed. 3. A rotary oil amount detecting means for detecting a rotational speed or a supply oil amount of the left and right hydraulic motors,
In a state where the opening / closing control valve is opened, when the difference between the rotation speed or the supply oil amount of the left and right hydraulic motors detected by the rotation oil amount detection unit is equal to or greater than a second predetermined value, the control unit 3. The operation control of the supply control valve according to claim 1, wherein the opening / closing control valve is closed, and the operation control of the supply control valve is performed so that the difference in the rotation speed or the supply oil amount is less than the second predetermined value. Travel control device for hydraulically driven vehicles. 4. A rotary oil amount detecting means for detecting a rotational speed or a supply oil amount of the left and right hydraulic motors,
In a state where the opening / closing control valve is opened, when the difference between the rotation speed or the supply oil amount of the left and right hydraulic motors detected by the rotation oil amount detection unit is equal to or greater than a second predetermined value, the control unit And controlling the operation of the supply control valve so that the difference between the rotational speed or the supply oil amount is less than the second predetermined value.
A travel control device for a hydraulically driven vehicle according to claim 1.