JP3787089B2 - Boom operation control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a boom operation control device including a telescopic boom.
[0002]
[Prior art]
2. Description of the Related Art Boom operation control devices including a telescopic boom are widely used. As an example, there is a boom operation control device for an aerial work vehicle. An aerial work platform is provided with a boom that can freely extend and contract on the vehicle body, and a work table for operator boarding is provided at the end of the boom. By operating the upper operation device provided to cause the boom to perform an expansion and contraction operation, the work table is moved to a desired position to perform the work. Such an aerial work vehicle is widely used for power distribution work and construction work.
[0003]
The boom of such an aerial work vehicle is generally composed of a plurality of boom members that are telescopically inserted and retracted and configured to expand and contract by an operation of a hydraulic actuator. The connection between these boom members is provided with a resistance to a large bending moment load acting on the boom and is configured to be slidable. Between the inner and outer peripheral surfaces of the boom member via a sliding member (hereinafter referred to as a slider) provided on the inner peripheral surface of the upper end of each of the boom members. Has been.
[0004]
[Problems to be solved by the invention]
However, when performing inching by so-called boom expansion / contraction operation in which the boom is slightly expanded and contracted to adjust the work table to a predetermined position, the boom expansion / contraction operation speed, that is, the sliding speed between the slider and the boom member decreases. Therefore, a stick-slip phenomenon may occur between the solid contact surfaces, and the boom may be extended and contracted intermittently with vibration. As a result, the work table disposed at the tip of the boom vibrates intermittently, which may cause discomfort to the operator who is on the work table. In order to prevent this, measures such as changing the material of the slider and improving the grease applied to the slider have been taken, but there are limits to completely preventing the stick-slip phenomenon. Was desired.
[0005]
The present invention has been made in view of such a problem, and an object of the present invention is to provide a boom operation control device configured to prevent a stick-slip phenomenon that occurs during a slow speed expansion / contraction operation of a boom.
[0006]
[Means for Solving the Problems]
In order to achieve such an object, in the present invention, a telescopic boom, a telescopic cylinder for performing the telescopic operation of the boom, a pump for supplying hydraulic oil to the telescopic cylinder, and a tilt for performing the telescopic operation of the boom are provided. A boom operation control device comprising an operating means to be operated (for example, the expansion / contraction operation lever 23 in the embodiment) and a boom operation control valve for controlling supply of hydraulic oil from the pump to the expansion / contraction cylinder according to the operation of the operation means. Is configured. The boom operation control device calculates the target expansion / contraction speed of the boom according to the tilting operation angle of the operation means. If the target expansion / contraction speed is equal to or less than the predetermined minimum speed set in the boom operation control device, the boom operation control device The boom operation control valve is controlled so as not to supply hydraulic oil.
[0007]
According to the boom operation control apparatus configured as described above, when the target expansion / contraction speed calculated by the controller is equal to or lower than the predetermined minimum speed, the boom operation control valve is controlled so as not to supply hydraulic oil to the expansion / contraction cylinder. If the minimum speed is the speed at which the stick-slip phenomenon occurs, the boom does not extend and contract in the speed region where the stick-slip phenomenon occurs, so that the stick-slip phenomenon can be prevented.
[0008]
According to a second aspect of the invention, a telescopic boom, a telescopic cylinder for performing the telescopic operation of the boom, a pump for supplying hydraulic oil to the telescopic cylinder, and an operating means operated for performing the telescopic operation of the boom ( For example, the telescopic operation lever 23) in the embodiment, the boom length detecting means provided on the boom for detecting the length of the boom, and the supply control of the hydraulic oil from the pump to the telescopic cylinder according to the operation of the operating means. A boom operation control device is configured to include a boom operation control valve to be performed and a controller that controls the operation of the boom operation control valve. Then, when the operation means is operated, the boom operation control device calculates the boom extension speed from the amount of change in the boom length detected by the boom length detection means for a predetermined time, and the boom extension speed is calculated in advance. When the speed is less than the predetermined minimum speed set in the controller, the boom operation control valve is controlled to increase the amount of hydraulic oil supplied to the telescopic cylinder. In this way, when the boom expansion / contraction speed is less than the minimum speed, the amount of hydraulic oil supplied to the expansion / contraction cylinder is controlled to be increased more than usual, so the stick-slip phenomenon can be prevented more reliably. Can do.
[0009]
Furthermore, it is preferable not to output control to the boom operation control valve when the target expansion / contraction speed is equal to or lower than the minimum speed. In this way, when the target expansion / contraction speed calculated by the controller is equal to or lower than the minimum speed, the control output itself is not performed on the boom operation control valve, so that the stick-slip phenomenon can be prevented more reliably.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. An aerial work vehicle 1 equipped with a boom operation control device according to the present invention is shown in FIG. This aerial work vehicle 1 is capable of traveling with front and rear wheels 3a and 3b, and is constructed based on a truck vehicle having a driving cabin 2a at the front. On the vehicle body 2 of the truck vehicle, a turntable 4 that is driven by a turn motor 13 (hydraulic motor) (not shown) and configured to be able to turn horizontally is disposed. A base 5 is pivotally connected to the swivel 4 and a boom 5 is attached. The boom 5 is moved up and down by a hoisting cylinder 6. The boom 5 is configured such that a base boom 5a, an intermediate boom 5b, and a tip boom 5c are slidably combined in a telescopic manner, and can be expanded and contracted by a built-in telescopic cylinder 7.
[0011]
The tip boom 5c has a boom head 5d at the tip, and is pivotally connected to the boom head 5d and attached to the support member 8 so as to be swingable up and down. The support member 8 has a vertical post portion (not shown), and swinging control of the support member 8 is performed by a leveling cylinder 12 disposed between the boom head 5 d and the support member 8. Regardless of the undulation, the support member 8 is controlled to swing so that the vertical post portion is always vertically extended. In this way, the work table 9 is attached to the vertical post portion that is always held vertically so as to be able to turn horizontally (swing freely), and the work table 9 is always held horizontally regardless of the undulation of the boom 5.
[0012]
The work table 9 is provided with an upper operation device 20 that is operated by an operator boarding here. The upper operation device 20 includes a raising / lowering operation lever 21 for performing the raising / lowering operation of the boom 5, a turning operation lever 22 for performing the turning operation of the swivel 4, and a telescopic operation lever 23 for performing the expansion / contraction operation of the boom 5.
[0013]
A lifting device 10 is provided at the upper end of the support member 8. In addition, outriggers 11 that are telescopically retractable are provided at four locations on the front, rear, left, and right of the vehicle body 2 so that when working at a high place, the vehicle body 2 can be lifted and supported as shown in the figure. It has become.
[0014]
Below, the boom operation control apparatus of the aerial work vehicle 1 is demonstrated with reference to FIG. This control device is configured to operate the boom operation control valve 26 by a control signal from the controller 25. The controller 25 receives operation signals from the hoisting operation lever 21, the turning operation lever 22 and the telescopic operation lever 23 and a detection signal from the boom length detector 27. The boom length detector 27 detects the boom length L of the boom 5 and outputs the boom length L to the controller 25.
[0015]
The hoisting operation lever 21, the turning operation lever 22 and the telescopic operation lever 23 are each configured to be tiltable from an upright state. When the tilting operation is performed, an operation signal corresponding to the tilting direction and proportional to the tilting angle is sent to the controller 25. Is output. The controller 25 controls the opening degree of the boom operation control valve 26 so that the flow rates corresponding to these operation signals are respectively supplied to boom actuators such as the hoisting cylinder, the telescopic cylinder 7 and the swing motor 13. In this case, the relationship between the operation signal (that is, the tilt angle of the operation lever) and the valve opening (that is, the supply flow rate to the hydraulic actuator) is set to be a proportional relationship as shown in FIG. 3, for example. As a result, if the turning operation lever 22 is tilted, hydraulic oil having a flow rate corresponding to the tilting angle is supplied to the turning motor 13, and the swivel 4 is turned at a speed corresponding to the tilting angle of the turning operation lever 22. . Similarly, even if the hoisting operation lever 21 and the telescopic operation lever 23 are tilted, hydraulic oil having a flow rate corresponding to each tilt angle is supplied to the hoisting cylinder 6 and the telescopic cylinder 7, and the hoisting operation lever 21 and the telescopic operation lever 23 are supplied. The boom 5 moves up and down at a speed corresponding to the tilting angle of, and expands and contracts. As can be seen from this, the amount of hydraulic oil required for each boom actuator corresponds to the tilt angle of each operation lever 21, 22, 23. The hydraulic fluid supplied to the hoisting cylinder 6, the telescopic cylinder 7 and the turning motor 13 is supplied from a hydraulic pump 30 driven by the engine.
[0016]
The contents of this control will be described with reference to FIG. First, when an operation signal from the hoisting and turning operation levers 21 and 22 is detected, the hoisting cylinder supply flow rate required for operating the corresponding hoisting cylinder 6 and the turning motor 13 at a speed corresponding to each operation signal. Q ₆ and the swing motor supply flow rate _{Q 13} are calculated. Then, the degree of opening of the boom operation control valve 26 is controlled so that the supply flow rates Q ₆ and Q ₁₃ are respectively obtained in the hoisting cylinder 6 and the swing motor 13.
[0017]
Next, control when an operation signal from the telescopic operation lever 23 is detected will be further described with reference to FIG. When an operation signal from the telescopic operation lever 23 is detected, the target telescopic speed Vo of the boom 5 is calculated in response to the operation signal. The target expansion / contraction speed Vo is a preset value corresponding to the operation signal of the expansion / contraction operation lever 23. When the controller 25 selects a setting value corresponding to the operation signal of the expansion / contraction operation lever 23, addition or multiplication processing is performed. The target expansion / contraction speed Vo is calculated earlier than the calculation using. When the target expansion / contraction speed Vo is equal to or lower than the minimum speed Vm preset in the controller 25 in order to avoid the stick-slip phenomenon, the control oil is not output to the expansion / contraction cylinder 7 without outputting a control signal to the boom operation control valve 26. Do not supply.
[0018]
On the other hand, when the target expansion / contraction speed Vo exceeds the minimum speed Vm, the expansion / contraction cylinder supply flow rate Q ₇ required to operate the corresponding expansion / contraction cylinder 7 at a speed corresponding to the operation signal from the expansion / contraction operation lever 23 is calculated. . Then, the boom expansion / contraction speed V is calculated from the change amount of the boom length L detected from the boom length detector 27 every predetermined time. When the boom expansion / contraction speed V is equal to or higher than the minimum speed Vm, the expansion / contraction cylinder 7 is expanded / contracted. as the cylinder supply flow rate Q ₇ are obtained controlling the opening degree of the boom actuation control valve 26. Thereby, the relationship between the operation signal from the telescopic operation lever 23 and the valve opening degree of the boom operation control valve 26 (that is, the telescopic cylinder supply flow rate Q ₇ ) is the expansion cylinder supply flow rate in the boom expansion / contraction speed region where the stick-slip phenomenon occurs. as Q ₇ becomes 0, and the boom telescopic speed range stick-slip phenomenon does not occur it is set to be proportional. Further, when the boom telescoping speed V is less than the minimum speed Vm is corrected flow rate Q _7a of the telescopic cylinder supply flow rate Q _7, calculated so as to increase a predetermined ratio with respect to telescopic cylinder feed flow rate Q _7. Then, the opening degree of the boom operation control valve 26 is controlled so that the correction flow rate Q _7a is obtained in the telescopic cylinder 7 so that the boom telescopic speed V reaches the target telescopic speed Vo.
[0019]
As described above, when the target expansion / contraction speed Vo calculated by the controller 25 is equal to or less than the predetermined minimum speed Vm, the boom operation control valve 26 is controlled so as not to supply the hydraulic oil to the expansion / contraction cylinder 7, so the minimum speed Vm Is the speed at which the stick-slip phenomenon occurs, the boom 5 does not extend and contract in the speed region where the stick-slip phenomenon occurs, and therefore the stick-slip phenomenon can be prevented. On the other hand, when the target expansion / contraction speed Vo exceeds the minimum speed Vm, when the boom expansion / contraction speed V becomes less than the minimum speed Vm, the amount of hydraulic oil supplied to the expansion / contraction cylinder 7 is increased by a predetermined rate to increase the boom expansion / contraction speed. Since V is controlled to reach the target expansion / contraction speed Vo, the stick-slip phenomenon can be prevented more reliably. Further, when the target expansion / contraction speed Vo is equal to or lower than the minimum speed Vm, the control output itself is not performed to the boom operation control valve 26, so that the stick-slip phenomenon can be prevented more reliably.
[0020]
In this example, the boom telescopic speed V is calculated from the amount of change of the boom length L detected from the boom length detector 27 every predetermined time. However, the present invention is not limited to this, and the boom telescopic speed V is supplied to the telescopic cylinder 7. The boom expansion / contraction speed V may be calculated from the flow rate of the hydraulic oil.
[0021]
【The invention's effect】
As described above, according to the present invention, when the target expansion / contraction speed calculated by the controller is equal to or lower than the predetermined minimum speed, the boom operation control valve is controlled not to supply hydraulic oil to the expansion / contraction cylinder. Is a speed at which the stick-slip phenomenon occurs, the boom does not extend and contract in the speed region where the stick-slip phenomenon occurs, and therefore, the stick-slip phenomenon can be prevented.
[0022]
Also, the boom expansion / contraction speed is calculated from the amount of change in the boom length detected by the boom length detection means provided on the boom for a predetermined time, and when the boom expansion / contraction speed is less than the minimum speed, By controlling the boom operation control valve so as to increase the supply amount of hydraulic oil , when the boom expansion / contraction speed becomes less than the minimum speed, control is performed to increase the supply amount of hydraulic oil to the expansion cylinder more than usual. Therefore, the stick-slip phenomenon can be prevented more reliably.
[0023]
Furthermore, it is preferable not to output control to the boom operation control valve when the target expansion / contraction speed is equal to or lower than the minimum speed. In this way, when the target expansion / contraction speed calculated by the controller is equal to or lower than the minimum speed, the control output itself is not performed on the boom operation control valve, so that the stick-slip phenomenon can be prevented more reliably.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a control device configuration of an aerial work vehicle including a boom operation control device according to the present invention.
FIG. 2 is a perspective view of an aerial work vehicle according to the present invention.
FIG. 3 is a graph showing the relationship between the valve opening degree of the boom operation control valve, the undulation, and the operation angle of the turning operation lever.
FIG. 4 is a graph showing the relationship between the valve opening degree of the boom operation control valve and the operation angle of the telescopic operation lever.
[Explanation of symbols]
2 Car body 5 Boom 7 Telescopic cylinder 9 Work table 20 Upper operation device 23 Telescopic operation lever (operation means)
25 Controller 26 Boom operation control valve 27 Boom length detector 30 Hydraulic pump L Boom length V Boom expansion / contraction speed Vm Minimum speed Vo Target expansion / contraction speed

Claims (3)

Telescopic boom,
A telescopic cylinder for performing the telescopic operation of the boom;
A pump for supplying hydraulic oil to the telescopic cylinder;
An operation means that is tilted to cause the boom to extend and retract;
A boom operation control valve that controls the supply of hydraulic oil from the pump to the telescopic cylinder according to the operation of the operation means;
A controller for controlling the operation of the boom operation control valve,
The controller calculates a target expansion / contraction speed of the boom according to a tilt operation angle of the operation means, and when the target expansion / contraction speed is equal to or less than a predetermined minimum speed set in the controller in advance, the controller operates the expansion / contraction cylinder. A boom operation control device that controls the boom operation control valve so as not to supply oil. Telescopic boom,
A telescopic cylinder for performing the telescopic operation of the boom;
A pump for supplying hydraulic oil to the telescopic cylinder;
Operating means operated to cause the boom to extend and retract;
A boom length detecting means provided on the boom for detecting the length of the boom;
A boom operation control valve that controls the supply of hydraulic oil from the pump to the telescopic cylinder according to the operation of the operation means;
A controller for controlling the operation of the boom operation control valve,
The controller calculates a boom expansion / contraction speed from a change amount of the boom length detected by the boom length detection means for a predetermined time when the operation means is operated, and the boom expansion / contraction speed is calculated in advance. A boom operation control device that controls the boom operation control valve to increase the supply amount of hydraulic oil to the telescopic cylinder when the speed is less than a predetermined minimum speed set in the controller .   The boom operation control device according to claim 1, wherein the controller does not output a control output to the boom operation control valve when the target expansion / contraction speed is equal to or less than the minimum speed.

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