JP2003322113A - Operation control device for working vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To operate a boom smoothly by a hydraulic pump with the small amount of supplied operating oil. <P>SOLUTION: This operation control device 50 includes operation control valves 60, 61 and 62 for controlling the supply/discharge of operation oil to actuators 13, 21 and 23 that drive a boom, a first hydraulic pump P1 that supplies the operation oil to the valves, a second hydraulic pump P2 that supplies the operation oil to the valves with lower performance for supplying the operation oil, a boom operation device 33 for driving the actuators, a switch 40 for emergency drive for driving the pump P2, and a controller 51 that controls the flow rate of the operation oil by the valves according to the operation of the device 33 based on a second flow rate characteristic considering the supply flow rate of the pump P2 when the pump P2 is in a driven state by the switch 40, or based on a first flow rate characteristic considering the supply flow rate of the pump P1 when the pump P2 is not in the driven state. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an operation control device for a work vehicle, and more particularly to an actuator for driving the work device, an operation control valve for performing hydraulic oil supply / discharge control for the actuator, and an operation control valve. A first hydraulic pump that supplies hydraulic oil and a second hydraulic pump that supplies hydraulic oil to an operation control valve and has a hydraulic oil supply capacity lower than that of the first hydraulic pump, and supplies hydraulic oil from the first hydraulic pump. The present invention relates to an operation control device for a work vehicle that drives an actuator by supplying hydraulic oil from a second hydraulic pump when the vehicle is in a stopped state.

[0002]

2. Description of the Related Art A work vehicle equipped with such an operation control device is constructed on the basis of a truck vehicle which can run, and is generally constructed by mounting the work device. The work device is mounted on a vehicle and is swingable, a boom that is rotatably pivoted on the swivel and is extendable and retractable, and a boom tip is swingably pivoted up and down. Some have a work table. The boom is hoisted by a hoisting cylinder, and is telescopically moved by a telescopic cylinder incorporated in the boom. The swivel base can be swung by a swivel motor mounted on the vehicle, and the operation of a hoisting cylinder, a telescopic cylinder, and a swivel motor (hereinafter collectively referred to as "actuator") is controlled by an operation control device. .

An example of the operation control device is shown in FIG. In addition,
FIG. 7 shows a case where the operation of the undulating cylinder is controlled. As shown in the figure, the operation control valve 60 is connected to the first oil passage 72 connected to the rod chamber 21b of the undulating cylinder 21 and the second oil passage 71 connected to the bottom chamber 21a of the undulating cylinder 21, and thus to the first hydraulic pump P1. Alternatively, the hydraulic oil supplied from the second hydraulic pump P2 is supplied to control the supply and discharge of the hydraulic oil to the undulating cylinder 21. The second hydraulic pump P2 is an emergency pump for driving the actuator at the minimum necessary flow rate when the first hydraulic pump P1 is stopped and the undulating cylinder 21 cannot be driven. Therefore, as the second hydraulic pump P2, a pump having a capacity smaller than that of the first hydraulic pump P1 is generally used. Here, the first hydraulic pump P1 is connected to a hydraulic motor 67 that receives the driving force from the engine E to rotate, and the second hydraulic pump P2 receives the driving force from the electric motor 69 to rotate. Has been done.

When the operation control valve 60 is switched to one side, the operation control valve 60 causes the operation oil supplied from the first hydraulic pump P1 or the second hydraulic pump P2 to flow into the first oil passage 72, and the bottom chamber 21a of the undulating cylinder 21. When the hydraulic oil that has flowed out of the hydraulic fluid flows from the second hydraulic passage 71 to the undulating cylinder 21 and the operation control valve 60 is switched to the other side, the hydraulic oil is supplied from the first hydraulic pump P1 or the second hydraulic pump P2. The hydraulic oil is caused to flow into the second oil passage 71, and the rod chamber 21 of the undulating cylinder 21
The hydraulic oil flowing out from b is flown into the first oil passage 72 to extend the undulating cylinder 21.

The operation of the operation control valve 60 for extending and retracting the undulating cylinder 21 is controlled by the controller 90. The boom operation device 33 for operating the boom and the emergency drive switch 40 that is operated when the electric motor 69 is driven to rotationally drive the second hydraulic pump P2 are electrically connected to the controller 90. . The boom operating device 33 has a tiltable hoisting operation lever 33b for operating the operation of the hoisting cylinder 21, and when the hoisting operation lever 33b is tilted to one side, the hoisting cylinder 21 is contracted and tilted to the other side. Then, the hoisting cylinder 21 extends and the expansion / contraction speed of the hoisting cylinder 21 changes according to the tilt amount of the hoisting operation lever 33b. The controller 90 is the first hydraulic pump P1.
The hydraulic oil flow rate is controlled by the operational control valve 60 according to the tilting operation (tilting direction and tilting amount) of the up-and-down operating lever 33b based on the first flow rate characteristic in consideration of the flow rate of hydraulic oil supplied from Has been done. As a result, when the hoisting operation lever 33b is tilted in either direction, the operation control valve 60 controls the hydraulic oil flow rate to the hoisting cylinder 21 according to the tilting direction and the tilting amount, and the hoisting cylinder 21 tilts. It expands and contracts at a speed according to the amount.

A holding valve 75 is provided in the second oil passage 71 connected to the undulating cylinder 21. The holding valve 75 allows the flow of hydraulic oil from the operation control valve 60 to the bottom chamber 21a side of the undulating cylinder 21, and operates from the bottom chamber 21a when the hydraulic pressure in the first oil passage 72 exceeds a predetermined pressure. Allows the flow of hydraulic oil to the control valve 60 side. The holding valve 75 is connected to the first oil passage 72 when the boom is tilted, that is, when the boom cylinder 21 is contracted.
Only when the hydraulic pressure in the first rod chamber 21b exceeds a predetermined pressure, the hoisting cylinder 21 is contracted to prevent the boom from suddenly falling.

[0007]

When the first hydraulic pump is stopped for some reason and the second hydraulic pump is driven to tilt the boom while the tilting angle of the hoisting operation lever remains the same, If the second hydraulic pump is driven,
The hydraulic oil discharged from the second hydraulic pump is supplied to the first oil passage through the operation control valve, but the supply flow rate thereof is smaller than that of the first hydraulic pump. Further, the operation control valve controls the hydraulic oil flow rate to the undulating cylinder according to the operation of the undulating operation lever based on the first flow rate characteristic in consideration of the flow rate of the hydraulic oil supplied from the first hydraulic pressure supply source. Therefore, when the holding valve is opened by the hydraulic pressure supplied from the second hydraulic pump and the undulating cylinder contracts, the hydraulic oil discharged from the undulating cylinder flows through the second oil passage and flows out of the operation control valve. The flow rate is higher than the supply flow rate of the hydraulic oil supplied to the first oil passage. As a result, when the amount of decrease in the hydraulic pressure in the first oil passage becomes large and the pilot pressure acting on the holding valve becomes smaller than a predetermined pressure, the opening holding valve closes and the boom swaying stops. . Then, when the hydraulic pressure in the first oil passage again exceeds the predetermined pressure, the holding valve is opened and the boom stumbling is restarted. That is, there is a problem that the boom falls over while performing intermittent operation. The same problem occurs when the boom is contracted.

The present invention has been made in view of the above problems, and when a boom is operated using a hydraulic pump with a small amount of hydraulic oil supplied, the work vehicle can be operated smoothly. An object is to provide a control device.

[0009]

In order to solve the above problems, an operation control device for a work vehicle according to the present invention includes a work device (for example, the boom 20 in the embodiment) and an actuator for driving the work device (for example, Swing motor 13, undulating cylinder 21, telescopic cylinder 2 in the embodiment
3), an operation control valve for performing hydraulic oil supply / discharge control for the actuator, and a first hydraulic pressure supply source for supplying hydraulic oil to the operation control valve (for example, the first hydraulic pump P in the embodiment).
1) and a second hydraulic pressure supply source that supplies hydraulic oil to the operation control valve and has a lower hydraulic oil supply capacity than the first hydraulic pressure supply source (for example,
The second hydraulic pump P2 in the embodiment, the work operating means operated to operate the actuator (for example, the boom operating device 33 in the embodiment), and the hydraulic pressure operated to drive the second hydraulic supply source. Drive operation means (for example, the emergency drive switch 4 in the embodiment)
0) and when the second hydraulic pressure supply source is not driven by the hydraulic drive operation means, the work operation means is based on the first flow rate characteristic in consideration of the flow rate of the hydraulic oil supplied from the first hydraulic pressure supply source. When the hydraulic drive operation means is operated and the second hydraulic pressure supply source is in a drive state, the operation control valve controls the flow rate of the hydraulic oil to the actuator according to the operation of the second hydraulic pressure supply source. And an operation control means (for example, the controller 51 in the embodiment) for controlling the hydraulic oil flow rate to the actuator by the operation control valve according to the operation of the work operation means based on the second flow rate characteristic in consideration of the oil flow rate. Configured.

According to the operation control device having the above structure, when the hydraulic drive operation means is operated and the second hydraulic pressure supply source is in the drive state, the operation control valve controls the operation oil supplied from the second hydraulic pressure supply source. By controlling the hydraulic oil flow rate to the actuator according to the operation of the work operation means based on the second flow rate characteristic in consideration of the flow rate, the first hydraulic pump stops for some reason, and the second hydraulic pump When the boom is operated by means of the hydraulic fluid discharged from the second hydraulic pump, when the actuator operates, the outflow rate of the hydraulic fluid discharged from the actuator and flowing out from the operation control valve is compared with the supply rate of the hydraulic fluid supplied to the actuator. The amount can be substantially the same or smaller than the supply flow rate. Therefore, fluctuations in the operating speed of the actuator are prevented, and the boom can be operated smoothly.

In the operation control device having the above-mentioned structure, the work operation means is a first work operation means (for example, the boom operation device 33 in the embodiment) and a second work operation means (for example, implemented) which are operated to operate the actuator. The emergency fall operation device 87) according to the first embodiment, and the operation control means, when the second hydraulic pressure supply source is not driven by the hydraulic drive operation means, based on the first flow rate characteristic, the first work operation means. Operation control valve for controlling the flow rate of the hydraulic oil to the actuator according to the operation of the operation control valve (for example, the first operation control circuit 8 in the embodiment).
1), and when the hydraulic drive operation means is operated and the second hydraulic pressure supply source is in the drive state, the second flow rate characteristic is set to the second flow rate characteristic.
Second operation control means (for example, second operation control circuit 82 in the embodiment) for controlling the hydraulic oil flow rate to the actuator by the operation control valve according to the operation of the work operation means.
And may be configured.

According to the operation control device having the above structure, the first operation control means controls the operation of the operation control valve in response to the operation of the first work operation means, and the second operation control means operates in response to the operation of the second work operation means. Since the operation control means controls the operation of the operation control valve, the second work operation means is operated even if the first operation control means fails and the operation control valve cannot be operated. For example, the second operation control means can control the operation of the operation control valve according to the operation of the second work operation means to drive the work device. Further, since the second operation control means controls the operation of the operation control valve according to the operation of the second work operation means, the work device can be driven at a desired speed.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to FIGS. The present embodiment shows a mode of an aerial work vehicle in which a work platform is provided at the tip of a boom configured to be extendable and retractable.

[0014]

[First Embodiment] A first embodiment of an operation control device according to the present invention will be described. First, before explaining the operation control device, an aerial work vehicle equipped with the operation control device will be described. As shown in FIG. 1, the aerial work vehicle 1 is configured with a truck vehicle as a base, and is capable of traveling by disposing wheels 5 on both front and rear left and right ends of the vehicle body 3 and driving on the front portion of the vehicle body 3. A cabin 7 is provided, and jacks 9 for lifting and supporting the vehicle body 3 are provided on both left and right front and rear portions of the vehicle body 3. A swivel base 11 capable of swiveling is attached to a rear portion of the vehicle body 3, and is configured to be swivelable by a swivel motor 13 incorporated in the vehicle body 3. A boom 20 is attached to the upper portion of the swivel base 11 and has a base portion pivotally connected so as to be movable up and down. The boom 20 can be hoisted by a hoisting cylinder 21.

The boom 20 has a base boom 2 from the base end side.
0a, the intermediate boom 20b, and the tip boom 20c are telescopically combined to be telescopically movable, and are configured to be telescopically movable by a telescopic cylinder 23 incorporated therein. A vertical post 27 is pivotally connected to the front end portion of the tip boom 20c so as to be vertically swingable, and is extended and contracted according to the hoisting angle of the boom 20 by a leveling cylinder (not shown) to perform vertical post 2 movement.
7 is held vertically. A workbench 30 is attached to an upper part of the vertical post 27 so as to be horizontally pivotable.
A boom operating device 33 for operating the drive of the boom 20 and a second hydraulic pump (to be described later) are provided on the workbench 30.
There is provided an emergency drive switch 40 that is operated when driving the.

The boom operating device 33 includes a swivel operating lever 33a that is operated when swiveling the swivel base 11, and a hoisting operating lever 3 that is operated when hoisting the boom 20.
3b and a telescopic operation lever 33c operated when the boom 20 is telescopically moved. These operation levers 33a, 33b, 33c are configured to be tiltable in the front-rear direction or the left-right direction. When the turning operation lever 33a is tilted to one side, the turning motor 13 turns to one side to turn the turntable 11 to one side, and when the turning operation lever 33a is tilted to the other side, the turning operation lever 33a turns. Motor 1
3 can rotate to the other side to rotate the swivel base 11 to the other side, and when the hoisting operation lever 33b is tilted to one side, the hoisting cylinder 21 extends and the boom 20 is hoisted. When the hoisting operation lever 33b is tilted to the other side, the hoisting cylinder 21 contracts and the boom 2 moves.
You can lay down 0. When the telescopic operation lever 33c is tilted to one side, the telescopic cylinder 23 extends to extend the boom 20, and when the telescopic operation lever 33c is tilted to the other side, the telescopic cylinder 2 is extended.
3 can be contracted and the boom 20 can be contracted. These operating levers 33a, 33b, 33c can change the operating speed of the boom 20 according to the tilt angle. Specifically, as the tilt angle increases, the boom 2 can be changed.
The operating speed of 0 can be increased.

The emergency drive switch 40 is constructed so that it can be tilted, and when it is tilted to one side (ON operation), a second hydraulic pump, which will be described later, is driven, and this is tilted to the other side (OFF operation). And the second hydraulic pump is stopped.

Next, the operation control device according to the present invention will be described. The operation control device is the boom operation device 3 described above.
3, the operation of the swing motor 13, the hoisting cylinder 21, and the telescopic cylinder 23 (hereinafter collectively referred to as "actuator 13, 21, 23") is controlled, and the emergency drive switch 40 is operated. It has a function of controlling the drive of the second hydraulic pump according to the above. The operation control device 50, as shown in FIG.
3, an emergency drive switch 40, and a controller 51
And operation control valves 60, 61, 62 for controlling the supply and discharge of hydraulic oil to the actuators 13, 21, 23, the first hydraulic pump P1 for supplying the operation oil to these operation control valves 60, 61, 62, and the first hydraulic pump P1. 2 Hydraulic pump P2 and operation control valve 6
0, 61, 62, and a pressure switch 65 for detecting the hydraulic pressure of the hydraulic oil supplied.

Since the boom operating device 33 and the emergency drive switch 40 have been described above, their description will be omitted. The first hydraulic pump P1 is connected to a hydraulic motor 67, and the hydraulic motor 67 is configured to be rotationally driven by receiving a driving force of an engine E mounted on a vehicle. The driving force of the engine E is the power take-off mechanism (hereinafter, referred to as “P
"TO mechanism". ) Is taken out by the hydraulic motor 6
7 is transmitted. The second hydraulic pump P2 is an emergency pump used when the first hydraulic pump P1 stops for some reason, has a smaller capacity than the first hydraulic pump P1, and is rotationally driven by the electric motor 69.

The controller 51 operates the turning operation lever 33a, the hoisting operation lever 33b and the telescopic operation lever 33c of the boom operating device 33 (tilt direction and tilt angle).
The operation of the operation control valves 60, 61, 62 for controlling the operation of the actuators 13, 21, 23 in accordance with
The rotation drive of the electric motor 69 is controlled according to the operation.

The operation control valves 60, 61, 62 whose operation is controlled by the controller 51 will be described below. FIG. 3 shows an example of the operation control valve 60 connected to the undulating cylinder 21, and as shown in the figure, the operation control valve 60 is a 4-port 3-position electromagnetic directional control valve, and the solenoid 60a on one side is excited. Then, the working oil is supplied to the second oil passage 71 connected to the bottom chamber 21a of the undulating cylinder 21, and the working oil in the rod chamber 21b is caused to flow to the first oil passage 72 connected to the rod chamber 21b of the undulating cylinder 21 by undulating. When the cylinder 21 is extended and the solenoid 60b on the other side is excited, the working oil is supplied to the first oil passage 72, and the working oil in the bottom chamber 21a is caused to flow through the second oil passage 71 to shrink the undulating cylinder 21. It is configured to move. The operation control valve 61 and the swing motor 13 connected to the telescopic cylinder 23 shown in FIG.
The operation control valve 62 connected to the above is similar in configuration to the operation control valve 60 connected to the undulating cylinder 21 described above, and therefore its description is omitted.

The controller 51 shown in FIG. 2 corresponds to the operation contents of the operation levers 33a, 33b, 33c of the boom operation device 33, specifically, the operation levers 33a, 33.
The solenoid 60a, 60b on one side or the other side is selected according to the tilting direction of the b, 33c, and a current corresponding to the tilting angle of the operating lever is applied to the selected solenoid 60a, 60b to excite it. Control valves 60, 61, 6
2 controls the movement of a spool (not shown) incorporated therein, and controls the flow rate and direction of the hydraulic oil flowing out from the operation control valves 60, 61, 62.

The operation oil flow rate control by the operation control valve 60 is as follows.
Tilting of the undulating operation lever 33b based on the first flow rate characteristic in consideration of the flow rate of the hydraulic oil supplied from the first hydraulic pump P1 and the second flow rate characteristic in consideration of the flow rate of the hydraulic oil supplied from the second hydraulic pump P2. The flow rate is controlled according to the operation (tilt direction and tilt amount). More specifically, FIG.
Is a graph showing the flow rate characteristic of the hydraulic oil flowing out from the operation control valve 60 when the first hydraulic pump P1 and the second hydraulic pump P2 are driven, and the vertical axis shows the outflow rate Q,
The horizontal axis represents the current I supplied to the solenoids 60a and 60b. The current I in FIG. 4 corresponds to the tilting angle of the operating lever 33b, and shows that the outflow rate Q increases as the tilting angle of the operating lever 33b increases.
As shown in FIG. 4, the flow rate characteristic of the hydraulic oil by the operation control valve 60 when the first hydraulic pump P1 shown in FIG. 3 is in the driving state is shown by the solid line in FIG. 4, and the outflow shown by this solid line. The relationship between the flow rate Q and the current I (lever tilt angle) is shown in FIG.
In addition, the operation lever 33b is tilted at a certain angle, and the hydraulic oil discharged from the first hydraulic pump P1 is supplied from the operation control valve 60 to the first oil passage 72 to reduce the undulating cylinder 21. When moved, the second oil passage 71
It is set according to the tilt angle of the operating lever 33b so that the outflow rate of the hydraulic oil discharged from the operation control valve 60 to the tank T through the flow rate is smaller than the inflow rate of the hydraulic oil supplied to the first oil passage 72. Has been done. As a result, the fluctuation range of the hydraulic pressure of the hydraulic oil in the first oil passage 72, which accompanies the contraction movement of the undulating cylinder 21 shown in FIG. 3, falls within a predetermined value. The operation of the undulating cylinder 21 will be described later.

Further, the controller 51 shown in FIG. 2 considers the flow rate of the hydraulic oil supplied from the second hydraulic pump P2 when the emergency drive switch 40 is turned on and the second hydraulic pump P2 is in the driving state. Based on the above-described second flow rate characteristic, the flow rate control is performed according to the tilting operation (tilt direction and tilt amount) of the up-and-down operation lever 33b. The second flow rate characteristic is
The relationship between the outflow rate Q and the current I (lever tilt angle) indicated by the broken line in FIG. 4 is the relationship between the outflow rate Q and the current I (lever tilt angle) indicated by the solid line described above. Similarly, the operating lever 33b is tilted at a certain angle, and the hydraulic oil discharged from the second hydraulic pump P2 is supplied from the operation control valve 60 to the first oil passage 72 to cause the undulating cylinder 21 to move.
When the da is reduced, the outflow rate of the working oil discharged from the operation control valve 60 to the tank T through the second oil path 71 is smaller than the inflow rate of the working oil supplied to the first oil path 72. It is set according to the tilt angle of the operation lever 33b so as to decrease. As a result, the fluctuation range of the hydraulic pressure of the hydraulic oil in the first oil passage 72, which accompanies the contraction movement of the undulating cylinder 21 shown in FIG. 3, falls within a predetermined value.

The relationship between the tilt angle of the operating lever 33b and the current I flowing through the solenoids 60a and 60b will now be described. FIG. 5 is a graph showing the relationship between the lever tilt angle and the current I. The vertical axis represents the current I supplied to the solenoids 60a and 60b, and the horizontal axis represents the lever tilt angle. In the figure, the solid line shows the relationship between the lever tilt angle and the current I when the first hydraulic pump P1 shown in FIG. 3 is driven, and the broken line is driven by the second hydraulic pump P2 shown in FIG. The relation between the lever tilt angle and the current I is shown. As shown in FIG. 5, the controller 51 shown in FIG. 2 operates the operation lever 3 when the emergency drive switch 40 is turned on and the second hydraulic pump P2 enters the drive state.
A current I indicated by a broken line is supplied to the solenoids 60a and 60b according to the tilt angle of 3b. As a result, for example, when the first hydraulic pump P1 shown in FIG. 2 is in a driving state, the operation lever 33b is tilted and tilted at a constant tilt angle, and the emergency drive switch 40 shown in FIG. When the second hydraulic pump P2 is turned on by being turned on, the controller 51 shown in FIG. 2 changes the current supplied to the solenoids 60a and 60b shown in FIG. 3 from I1 to I2 smaller than this. As a result, the outflow rate of the hydraulic oil flowing out from the operation control valve 60 shown in FIG.
In the case shown in (1), Q1 is decreased to Q2.

As shown in FIG. 2, the controller 51 determines whether the second hydraulic pump P2 is in a driving state or not by a pump connecting the first hydraulic pump P1 and the second hydraulic pump P2 to the operation control valve 60. It is determined by whether or not an ON signal is output from the pressure switch 65 connected to the pressure oil passage 17.
The pressure switch 65 is configured to output an ON signal when the hydraulic pressure in the pump pressure oil passage 17 due to the hydraulic oil supplied from the second hydraulic pump P2 exceeds a predetermined pressure. The controller 51 may determine whether or not the second hydraulic pump P2 is in the drive state by using the operation signal output when the emergency drive switch 40 is in the ON state.

A relay switch 53 is connected to the controller 51. The drive unit 53a of the relay switch 53 is electrically connected to the controller 51, and the switch unit 53b is arranged on the power supply line 55 that connects the power source 54 and the electric motor 69. When the drive unit 53a is in the excited state, the switch unit 53b is moved to the power supply line 55 to bring the power supply line 55 into the communication state, and when the drive unit 53a is in the non-excited state, the switch unit 53b is separated from the power supply line 55. The power supply line 55 is cut off. The drive control of the relay switch 53 is performed by the controller 51. When the emergency drive switch 40 is turned on and the controller 51 receives the ON signal from the emergency drive switch 40, the relay switch 53 is operated.
When the drive unit 53a of the relay switch 53 is energized to bring the power supply line 55 into the communication state and the OFF signal is received from the emergency drive switch 40, the drive unit 53a of the relay switch 53 is deactivated and the power supply line 55 is cut off. .

An operation control valve 6 whose operation is controlled in this way
A holding valve 75 is provided in the second oil passage 71 that connects between 0 and the bottom chamber 21a of the undulating cylinder 21, as shown in FIG. This holding valve 75 allows the flow of hydraulic oil from the operation control valve 60 to the bottom chamber 21a side of the undulating cylinder 21, and operates from the bottom chamber 71 when the hydraulic pressure in the first oil passage 72 exceeds a predetermined pressure. Allows the flow of hydraulic oil to the control valve 60 side. The holding valve 75 raises and lowers only when the boom 20 shown in FIG. 1 is tilted, that is, when the working hydraulic pressure in the first oil passage 72 exceeds a predetermined pressure when the hoisting cylinder 21 is contracted. Move the cylinder 21 back and forth,
A sudden fall of the boom 20 shown in FIG. 1 is prevented.

Next, the operation of the operation control device 50 according to the present invention will be described. As shown in FIG. 1, it is assumed that the aerial work vehicle 1 has the jack 9 overhanging to support the vehicle body 3 and the boom 20 is lifted at a predetermined hoisting angle. A case where the boom 20 is laid down will be described. Moreover, in this state, FIG.
It is assumed that the engine E shown in 1) is in a driving state, and the driving force of the engine E is taken out by a PTO mechanism (not shown) and the hydraulic motor 67 shown in FIG. 3 is rotationally driven. First, as shown in FIG. 2, the boom operating device 3
When the undulating operation lever 33b of No. 3 is tilted to the other side, the controller 51 causes the current according to the line indicated by the solid line in FIG. 5 according to the tilt angle of the operation lever 33b (FIG. 5).
In the inside, for example, when the lever tilt angle is θ1, a current I1) is caused to flow through the solenoid 60a of the operation control valve 60 shown in FIG. 3, and the operation oil flow rate by the operation control valve 60 is based on the first flow rate characteristic shown in FIG. The control is performed to supply the hydraulic oil discharged from the first hydraulic pump P1 to the first oil passage 72, as shown in FIG. When the hydraulic oil is supplied to the first oil passage 72, the hydraulic pressure of the first oil passage 72 rises and the first oil passage 7
2 is transmitted to the holding valve 75 through a pilot oil passage 76 that connects the 2 and the holding valve 75.
When the oil pressure in the oil passage 72 exceeds a predetermined pressure, the holding valve 75 opens to allow the flow of the working oil to the operation control valve 60 side in the second oil passage 71. As a result, the hoisting cylinder 21 contracts, and the boom 20 shown in FIG. 1 falls down.

Here, it is assumed that the rotation drive of the first hydraulic pump P1 is stopped for some reason, and the fall of the boom 20 shown in FIG. 1 is stopped. When the boom 20 is further tilted down in such a stopped state, the emergency drive switch 40 shown in FIG. 2 is turned on. When the emergency drive switch 40 is turned on, as shown in FIG. 2, the controller 51 operates the relay switch 53 to bring the power supply line 55 into a communication state, and supplies electric power from the power supply 54 to the electric motor 69. Then, the electric motor 69 is rotationally driven. When the electric motor 69 is rotationally driven, the second hydraulic pump P2 is driven, and as shown in FIG. 3, the second hydraulic pump P2 is driven.
The hydraulic fluid discharged from the pump raises the hydraulic pressure in the pump pressure oil passage 17, and when the hydraulic pressure exceeds a predetermined value, the pressure sensor 65 is turned off.
Output N signal. When the controller 51 receives the ON signal, the controller 51 determines that the second hydraulic pump P2 is driving. The controller 51 may be configured to determine that the second hydraulic pump P2 has been driven when receiving the ON signal from the emergency drive switch 40. In this case, the pressure sensor 65 becomes unnecessary.

The controller 51 also controls the solenoid 60 shown in FIG. 3 according to the tilting angle of the up-and-down operating lever 33b.
The current I flowing through is changed according to the line shown by the broken line in FIG. As shown in FIG. 5, for example, when the lever tilt angle is θ1, the current is changed to I2. As a result, as shown in FIG. 3, when the hydraulic oil discharged from the second hydraulic pump P2 is supplied to the first oil passage 72, the first oil passage 72
Oil pressure rises and is transmitted to the holding valve 75 through the pilot oil passage 76. When the oil pressure in the first oil passage 72 exceeds a predetermined pressure, the holding valve 75 opens and the operation control valve 60 in the second oil passage 71 is opened. Allowing the flow of hydraulic oil to the side, the hoisting cylinder 21 contracts and the boom 20 shown in FIG. 1 falls. The outflow rate of the hydraulic oil discharged from the operation control valve 60 by driving the second hydraulic pump P2 is greater than the hydraulic oil discharged from the operation control valve 60 before the emergency drive switch 40 shown in FIG. 2 is turned on. Therefore, the lodging speed of the boom 20 becomes slower.

Here, when the emergency drive switch 40 is turned on and the second hydraulic pump P2 is in the drive state, the hydraulic oil flow rate control based on the second flow rate characteristic by the operation control valve 60 is performed from the operation control valve 60. Since the outflow rate of the hydraulic oil discharged to the tank T is made smaller than the inflow rate supplied to the first oil passage 72, the hydraulic pressure fluctuation of the hydraulic oil in the first oil passage 72 due to the contraction movement of the undulating cylinder 21 is performed. The width fits within a small range. Therefore, even if the holding valve 75 is opened by the working hydraulic pressure supplied to the first oil passage 72 and the undulating cylinder 21 is contracted, the amount of fluctuation of the pilot hydraulic pressure 76 acting on the holding valve 75 is reduced. be able to. As a result, the once opened holding valve 75 is not closed and the contraction movement of the hoisting cylinder 21 is not restricted, and the boom 20 can be smoothly tilted.

In the above-described embodiment, the boom 20 is used.
Although the laying-down operation has been described, the same effect can be obtained when the boom 20 is contracted.

[0034]

Second Embodiment Next, a second embodiment of the operation control device according to the present invention will be described. Note that only the differences from the first embodiment will be described in the second embodiment, and the same aspects as those in the first embodiment will be assigned the same reference numerals and explanations thereof will be omitted. The controller 51 of the operation control device 50 is configured to include a first operation control circuit 81, a second operation control circuit 82, and an operation switching circuit 83. The first operation control circuit 81 includes the emergency drive switch 40.
Accordingly, when the second hydraulic pump P2 is not driven, the boom operating device 33 is operated based on the first flow rate characteristic.
Of the actuators 13, 2 by the operation control valves 60, 61, 62 according to the operation of the operation levers 33a 33b 33c of
It has a function of controlling the hydraulic oil flow rate to the first and the second hydraulic fluid. The second operation control circuit 82 includes the emergency drive switch 4
When the second hydraulic pump P2 is driven by 0, the hydraulic oil flow rate to the undulating cylinder 21 by the operation control valve 60 according to the operation of the emergency tilting operation device 87 described later based on the second flow rate characteristic. It has the function of controlling.

The operation switching circuit 83 is an operation control valve 60 for the control signal output from the first operation control circuit 81 when the operation device for emergency drive 87 is in a state of operating the second hydraulic pump P2. , 61, 62 are cut off, while the control signal output from the second operation control circuit 82 is transmitted to the operation control valve 60, and the emergency fall operation device 87 drives the second hydraulic pump P2. When the operation control valve 6 is not operated, the control signal output from the first operation control circuit 81 is applied to the operation control valve 6
0, 61, 62, while the second operation control circuit 82
It has a function of interrupting transmission of a control signal output from the control valve 60 to the operation control valve 60. The second operation control circuit 82 is electrically connected to the emergency falling operation device 87 described above that is operated when the boom 20 shown in FIG. 1 is moved down.

The emergency fall operation device 87 has an emergency fall operation lever 87a which can be tilted forward and backward or left and right.
When the emergency tilt operation lever 87a is tilted to one side, the hoisting cylinder 21 extends, and when the emergency tilt operation lever 87a is tilted to the other side, the hoisting cylinder 21 is contracted. In addition, the emergency fall operation lever 87a
Is configured so that the expansion / contraction speed of the undulating cylinder 21 increases as the tilt angle increases. That is, the contents of the operation of the emergency fall operation lever 87a are determined by turning on the emergency drive switch 40 shown in FIG.
2 has a function similar to that of the hoisting operation lever 33b of the boom operating device 33 when the boom operating device 33 is in the driving state.

According to such an operation control device 50, the first operation control circuit 81 fails and the operation control valves 60, 61,
Even in the case where the operation control of 62 cannot be performed, the emergency drive switch 40 is turned on and the emergency laying operation lever 87a is laid down.
The operation control circuit 82 controls the operation of the operation control valve 60 in accordance with the operation of the emergency tilt operation lever 87a to control the undulating cylinder 2.
The boom 20 can be laid down by moving 1 down. Further, the second operation control circuit 82 causes the operation control valve 6 to operate in accordance with the tilt operation amount (tilt angle) of the emergency fall operation lever 87a.
0 is changed according to the line shown by the broken line in FIG. 4, so that the boom 20 is moved by changing the tilting operation amount of the emergency fall operation lever 87a according to the attitude of the boom 20. It can be laid down at a desired speed.

Although an example in which the boom 20 shown in FIG. 1 is mounted on the vehicle in the above-described embodiment is shown, the vehicle has a scissor link mechanism for vertically moving a work table (not shown). Equipment, work equipment capable of inspecting bridges, and crane equipment may be installed. Further, although the above-described second hydraulic pump P2 has been shown to be used in an emergency, it is used as a low-noise battery-driven hydraulic pump in consideration of the environment of the work site and is actively used at the work site. The embodiment may be performed. In this case, when the capacity of the second hydraulic pump P2 is smaller than the capacity of the first hydraulic pump P1 described above, the same effect as in the case described above can be obtained.

[0039]

As described above, according to the work vehicle operation control device of the present invention, when the hydraulic drive operation means is operated and the second hydraulic pressure supply source is in the drive state, the operation control valve is The first hydraulic pump controls the hydraulic oil flow rate to the actuator according to the operation of the work operation means based on the second flow rate characteristic in consideration of the flow rate of the hydraulic oil supplied from the two hydraulic pressure supply sources. If you stop for some reason and operate the boom with the second hydraulic pump,
When the actuator is actuated by the hydraulic oil discharged from the second hydraulic pump, the outflow rate of the hydraulic oil discharged from the actuator and flowing out of the operation control valve is approximately the same as the supply rate of the hydraulic oil supplied to the actuator or a flow rate higher than the supply rate. Can also be small. Therefore, fluctuations in the operating speed of the actuator are prevented, and the boom can be operated smoothly.

[Brief description of drawings]

FIG. 1 is a left side view of an aerial work vehicle equipped with an operation control device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an operation control device according to an embodiment of the present invention.

FIG. 3 shows a hydraulic circuit diagram according to an embodiment of the present invention.

FIG. 4 is a graph showing an outflow characteristic of hydraulic oil of the operation control valve according to the embodiment of the present invention.

FIG. 5 is a diagram showing the relationship between the current supplied to the solenoid of the operation control valve and the lever tilt angle in the embodiment of the present invention.

FIG. 6 is a schematic configuration diagram of an operation control device according to a second embodiment of the present invention.

FIG. 7 shows a conventional hydraulic circuit diagram.

[Explanation of symbols]

1 aerial work vehicle 13 swing motor (actuator) 20 boom (working device) 21 hoisting cylinder (actuator) 23 telescopic cylinder (actuator) 33 boom operating device (working operation means, first working operation means) 40 emergency drive switch ( Hydraulic drive operation means) 50 Operation control device 51 Controller (operation control means) 60, 61, 62 Operation control valve 81 First operation control circuit (first operation control means) 82 Second operation control circuit (second operation control means) 87 Emergency operation device (second work operating means) P1 First hydraulic pump (first hydraulic supply source) P2 Second hydraulic pump (second hydraulic supply source)

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hiroshi Furusho             1015 1152 Yamashita, Ryoke, Ageo City, Saitama Prefecture               Aichi Corporation Ageo Kogyo             Inside the hall (72) Inventor Takashi Sasaki             1015 1152 Yamashita, Ryoke, Ageo City, Saitama Prefecture               Aichi Corporation Ageo Kogyo             Inside the hall F term (reference) 3F333 AA08 AB04 DB02 FA21 FA22                       FA29 FA32 FB04 FD07 FE09                       FH08                 3H082 AA01 BB08 CC02 DA06 DA22                       DA33 DA36 DA48 DB37 DE05                       EE01                 3H089 AA32 AA46 BB10 BB28 CC01                       DA02 DA08 DA13 DA14 DB08                       DB33 DB46 DB49 DB82 EE34                       GG02 JJ01

Claims (2)

[Claims] 1. A work apparatus, an actuator for driving the work apparatus, an operation control valve for performing hydraulic oil supply / discharge control for the actuator, and a first hydraulic pressure supply source for supplying hydraulic oil to the operation control valve. A second hydraulic pressure supply source that supplies hydraulic oil to the operation control valve and has a hydraulic oil supply capacity lower than that of the first hydraulic pressure supply source; a work operation unit that is operated to operate the actuator; Hydraulic drive operating means operated to drive the hydraulic supply, and an operation supplied from the first hydraulic supply when the second hydraulic supply is not driven by the hydraulic drive operating means. Based on the first flow rate characteristic in consideration of the oil flow rate, the operation oil flow rate control to the actuator is performed by the operation control valve according to the operation of the work operation means, When the pressure drive operation means is operated and the second hydraulic pressure supply source is in a drive state, the work operation means of the work operation means is operated based on the second flow rate characteristic in consideration of the flow rate of the hydraulic oil supplied from the second hydraulic pressure supply source. An operation control device for a work vehicle, comprising: an operation control means for controlling a hydraulic oil flow rate to the actuator by the operation control valve according to an operation. 2. The work operation means includes first work operation means and second work operation means operated to operate the actuator, and the operation control means uses the hydraulic drive operation means to operate the second work operation means. When the hydraulic power source is not driven,
The first operation control means for controlling the hydraulic oil flow rate to the actuator by the operation control valve according to the operation of the first work operation means based on the first flow rate characteristic, and the hydraulic drive operation means are operated. When the second hydraulic pressure supply source is in a driving state, the hydraulic oil flow rate control for the actuator is performed by the operation control valve according to the operation of the second work operation means based on the second flow rate characteristic. The operation control device for a work vehicle according to claim 1, wherein the operation control device comprises a second operation control means.