JP3662160B2 - Leveling equipment for aerial work platforms - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
According to the present invention, a worktable support member is disposed at the tip of a boom disposed on a vehicle body so as to be able to move up and down so as to swing up and down, and the worktable attached to the worktable support member is held horizontally. The present invention relates to a leveling device for an aerial work vehicle.
[0002]
[Prior art]
An aerial work platform moves the workbench to a desired height by raising and lowering and extending the boom while the operator is on the workbench, and the worker on the workbench performs various tasks such as overhead work. Used to do. Since an operator rides on the work table, a leveling device is usually provided in an aerial work vehicle to always keep the work table horizontal regardless of the boom up and down. For this reason, generally, a work table support member is attached to the tip of the boom so as to be swingable up and down, and swinging of the work table support member is controlled by a leveling cylinder according to the boom raising and lowering operation. The leveling device is configured to always hold the work table supported by the horizontal. Thus, the operation of the leveling cylinder that controls the swing of the worktable support member is configured to be performed by controlling the supply of the hydraulic pressure by the leveling valve according to the undulation angle of the boom, the inclination angle of the worktable, etc. There are known leveling devices.
[0003]
[Problems to be solved by the invention]
By the way, when such a leveling device is used to hold the work table horizontally, the axial force required for the leveling cylinder corresponds to the load (load) from the work table, and the larger the work table load, the larger the shaft. Power is required. In order to obtain a large axial force, it is only necessary to increase the diameter of the leveling cylinder or increase the supply hydraulic pressure, but increasing the supply hydraulic pressure leads to changes in the specifications of the hydraulic pump and the engine that drives the hydraulic pump. Therefore, it is difficult to set the leveling cylinder size according to the maximum load applied from the work table. However, if the size of the leveling cylinder is set according to the maximum load from the work table, there is a problem that the size of the leveling cylinder increases.
[0004]
The present invention has been made in view of such problems, and it is possible to perform high-altitude work in which leveling control can be performed without hindrance to a large load from a workbench without increasing the size of the leveling cylinder. An object of the present invention is to provide a car leveling device.
[0005]
[Means for Solving the Problems]
In order to achieve such an object, in the present invention, a leveling cylinder that swings a worktable support member that is swingably movable up and down at the tip of the boom, and one leveling cylinder that supplies hydraulic oil to the leveling cylinder are provided. A hydraulic pressure supply means, a leveling control valve for controlling the hydraulic pressure supply to the leveling cylinder according to the boom undulation and holding the work table horizontally, and a hydraulic pressure for amplifying the hydraulic pressure supplied to the leveling cylinder via the leveling control valve A leveling device for an aerial work vehicle is configured with an amplifying device. Then, the hydraulic pressure from the hydraulic pressure supply means is amplified by a hydraulic pressure amplifying device and supplied to the leveling cylinder at all times or as necessary.
[0006]
If the leveling device having such a configuration is used, a desired leveling operation can be performed without increasing the size of the leveling cylinder. For example, when the load (load) acting on the leveling cylinder from the work table is small, the hydraulic pressure supplied to the leveling cylinder may be relatively small, so that the leveling control is performed by directly supplying the hydraulic pressure from the hydraulic pressure supply means. When the load acting on the leveling cylinder is large, the hydraulic pressure supplied to the leveling cylinder can be amplified by the hydraulic pressure amplifying device to perform leveling control. Accordingly, leveling control can be performed without any trouble using the hydraulic pressure thus amplified without increasing the size of the leveling cylinder. At this time, the supply hydraulic pressure from the hydraulic supply means does not need to be high, and it is not necessary to change the specifications of the hydraulic pump and the engine that drives the hydraulic pump.
[0007]
That is, according to the present invention, it is possible to perform leveling control with respect to a work table load larger than the conventional one by using the hydraulic pressure supply means and the leveling cylinder having the same specifications as the conventional one. In other words, the leveling cylinder can be reduced in size without changing the specifications of the hydraulic pressure supply means for the same work table load as before.
[0008]
Also, a continuous discharge hydraulic booster device provided with a work table load detecting means for detecting a load acting on the leveling cylinder from the work table, and the hydraulic amplifying device disposed in the oil passage from the hydraulic supply means to the leveling cylinder. And an operation switching valve that switches an oil passage from the hydraulic supply means to the leveling cylinder to a bypass oil passage that bypasses the continuous discharge hydraulic booster device and an oil passage that passes through the continuous discharge hydraulic booster device. it can. In this case, when the load detected by the work bench load detecting means is below a predetermined value, the operation switching valve switches the oil path from the hydraulic supply means to the leveling cylinder to a bypass oil path that bypasses the continuous discharge hydraulic booster device. Thus , the hydraulic pressure is supplied to the leveling cylinder, and when the load detected by the work bench load detecting means exceeds a predetermined value, the operation switching valve connects the oil path from the hydraulic supplying means to the leveling cylinder through the continuous discharge type hydraulic booster device. By switching to the passing oil passage, the hydraulic oil pressure is amplified by the continuous discharge hydraulic booster device and supplied to the leveling cylinder. In this way, leveling control for a larger platform load than before can be achieved by simply adding a continuous discharge hydraulic booster device to the oil path from the hydraulic supply means to the leveling cylinder , or for the same platform load as before. Leveling control can be performed using a smaller leveling cylinder.
[0009]
Further, the hydraulic pressure amplifying device includes a pump motor unit disposed in an oil passage from the hydraulic pressure supply means to the leveling cylinder, and a motor generator unit having a rotation shaft connected to the rotation shaft of the pump motor unit. You can also. In this case, when the load detected by the work table load detecting means is equal to or less than a predetermined value, the pump generator unit is rotated by the hydraulic pressure supplied from the hydraulic pressure supplying means to the leveling cylinder, and power is generated by the motor generator unit. On the other hand, when the load detected by the platform load detecting means exceeds a predetermined value, the motor generator unit is driven, and the pump motor unit amplifies the hydraulic pressure from the hydraulic supply means on the oil path from the hydraulic supply means to the leveling cylinder. It can be switched by a signal from the platform load detection so as to be supplied to the leveling cylinder .
[0010]
By using the leveling device having such a configuration, not only leveling control with respect to a larger platform load than before, but also leveling control using a smaller leveling cylinder than before with respect to the same platform load as before can be performed. When the work bench load is small, the motor generator unit can generate power (energy regeneration) to save energy.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. An aerial work vehicle equipped with a leveling device according to the present invention is shown in FIG. The aerial work vehicle 10 has a truck-based vehicle body 11 having a driving cabin 12 at the front, a swivel base 13 is provided at the rear of the car body 11, and the swivel base 13 has a telescopic boom. 14 is pivoted by a foot pin 15 so as to be raised and lowered. The swivel base 13 can be swiveled horizontally by a swivel motor 18, the boom 14 can be swung by a hoisting cylinder 16, and can be stretched by a built-in telescopic cylinder 17.
[0012]
A vertical post (worktable support member) 20 is swingably attached to the tip of the boom 14, and a worktable 21 is attached on the vertical post 20 by a swing motor 22 so as to be pivotable (swinging freely). It has been. The operation of the leveling cylinder 23 is controlled so that the vertical post 20 is always held vertically and the work table 12 is kept horizontal regardless of the boom 14 being raised and lowered (this will be described later). The work table 12 is provided with an upper operation device 25 having an operation lever 27 that is operated by an operator boarding here. The swivel base 13 is also provided with a lower operation device 26 having an operation lever 28 operated by an operator. Outrigger jacks 19 are provided at four positions on the front, rear, left and right of the vehicle body 11 to lift and support the vehicle body 11 when working at a high place.
[0013]
When the aerial work vehicle 10 having such a configuration is used to perform a high altitude work, for example, a jack operating device (not shown) provided at the rear of the vehicle body with the boom 14 lying on the vehicle body 11 is stored. 2), the outrigger jack 19 is extended downward and the vehicle body 11 is lifted and supported as shown in FIG. Next, the lower operating device 26 or the upper operating device 25 is operated to perform the turning operation of the turntable 1, the raising and lowering operation of the boom 14, and the like to move the worktable 21 to a desired height. Work at height is performed by the boarded worker.
[0014]
In this way, when the boom 14 is raised and lowered when the work table 21 is moved to a desired height, leveling control for controlling the expansion and contraction of the leveling cylinder 23 to keep the work table 21 horizontal is performed. A leveling device that performs the leveling control will be described with reference to FIG.
[0015]
The hoisting cylinder 16 and the leveling cylinder 23 are both operated by receiving hydraulic pressure from a hydraulic pump P driven by the engine E. The undulation cylinder 16 is controlled by the hydraulic pressure supply controlled by the undulation control valve 30, and the leveling cylinder 23 is controlled by the hydraulic pressure supply by the leveling control (balance control) valve 35. Both the relief control valve 30 and the leveling control valve 35 are controlled in response to a control signal from the controller 40. In the oil passage from the leveling control valve 35 to the leveling cylinder 23, a continuous discharge hydraulic booster device 60 and a double pilot check valve 38 are disposed as shown in the figure.
[0016]
The controller 40 controls the operation of the undulation control valve 30 in response to the operation signal from the upper operation device 25 or the lower operation device 26 described above. As a result, the hoisting cylinder 16 is actuated in response to the operation of the hoisting levers of the operating devices 25 and 26, and the boom 14 is raised and lowered. A signal from an inclination detector 43 that detects the inclination of the work table 21 is also input to the controller 40, and the work table 21 is based on the detection signal from the inclination detector 43 when the boom 14 is raised and lowered. Is output to the leveling control valve 35 so as to be held horizontally. As a result, the operation control of the leveling cylinder 23 is performed so that the work table 21 is always horizontal regardless of the ups and downs of the boom 14. The tilt detector 43 may directly detect the tilt of the work table 21 with respect to the horizontal plane, or may detect the tilt of the work table 21 with respect to the vehicle body 11 based on the tilt angle of the boom 14 or the like.
[0017]
The controller 40 further receives a detection signal from a work bench load detector 45 that detects the hydraulic pressure in the bottom oil chamber of the leveling cylinder 23 and detects the load acting on the leveling cylinder 23 from the work bench 21. The work table load detector is not limited to this, and may be one that detects the axial force of the leveling cylinder 23 with a load cell or the like. The controller 40 controls the operation of the continuous discharge hydraulic booster device 60 according to the load detected by the work bench load detector 45. Specifically, when the load exceeds a predetermined value, the hydraulic booster device 60 is operated. First, the hydraulic booster device 60 will be described with reference to FIG.
[0018]
The hydraulic booster device 60 is connected and disposed between the four oil passages 52 to 55 shown in FIG. 1 as shown in FIG. The oil passage 52 and the oil passage 54 are connected via a first bypass oil passage 61 and a shuttle valve 62, and the oil passage 53 and the oil passage 55 are connected via a second bypass oil passage 63. For this reason, when the hydraulic booster device 60 is not operated, the leveling control valve 35 and the leveling cylinder 23 are directly connected via these bypass oil passages 61 and 63, and leveling control is performed using the hydraulic pressure supplied from the hydraulic pump P as it is. Is called.
[0019]
On the other hand, the hydraulic booster device 60 is basically composed of an operation switching valve 65 that is controlled in response to a control signal from the controller 40, and a booster mechanism 70 that performs hydraulic amplification, and includes a double-acting control valve 78 and a plurality of checks. The valve 75 and the like are arranged as shown in the figure, and the high pressure oil amplified by the booster mechanism 70 is supplied from the oil passage 81 to the oil passage 54 via the shuttle valve 62, and further, the leveling cylinder 23 Supply to bottom oil chamber.
[0020]
The operation switching valve 65 is operated by exciting a solenoid 65a in response to a control signal from the controller 40. The booster mechanism 70 includes a double-acting piston 71 that is reciprocated by receiving hydraulic oil supplied to the left and right cylinder chambers 72, 73, a booster piston 71 a that is integrally connected to the double-acting piston 71, and the double-acting piston 71. It consists of a double-acting control valve 78 that is connected and interlocked therewith. The booster piston 71 a is reciprocated in the booster cylinder chamber 74. The booster cylinder chamber 74 is connected to the oil passage 81 via the check valve 75.
[0021]
In the hydraulic booster device 60 having such a configuration, when high-pressure hydraulic oil is supplied into the bottom side oil chamber of the leveling cylinder 23, the solenoid 65a of the operation switching valve 65 is excited by a control signal from the controller 40 and is moved rightward. The hydraulic oil supplied through the oil passage 52 is supplied to the left cylinder chamber 72 of the booster mechanism 70 through the oil passage 82a. As a result, the double-acting piston 71 moves to the right together with the booster piston 71 a and supplies high-pressure hydraulic oil from the booster cylinder chamber 74 to the oil passage 81. When the double-action piston 71 moves to the right stroke end, the double-action control valve 78 connected thereto is switched, and the hydraulic oil from the oil passage 52 is also supplied to the right cylinder chamber 73 via the oil passage 82b. The pressure receiving area of the right cylinder chamber 73 is larger than the pressure receiving area of the left cylinder chamber 72. Due to this difference, the double acting piston 71 is now moved to the left. At this time, the booster piston 71a is also operated, but hydraulic oil is supplied from the oil passage 82c to the booster cylinder chamber 74 while maintaining the high pressure in the oil passage 81 by the action of the check valve 75.
[0022]
When the double-acting piston 71 moves to the left stroke end, the double-acting control valve 78 is switched, and the right cylinder chamber 73 remains in the double-acting control valve 78 while hydraulic oil is supplied to the left cylinder chamber 72 via the oil passage 82a. Connect to the drain through. For this reason, the double-acting piston 71 is again moved to the right upon receiving hydraulic oil supply from the oil passage 82a. Thereafter, the double-acting piston 71 is continuously reciprocated in this way, and high-pressure hydraulic oil is continuously supplied to the oil passage 81.
[0023]
As described above, in the continuous discharge hydraulic booster device 60 capable of supplying high-pressure hydraulic oil from the oil passage 54 to the leveling cylinder 23, the load of the leveling cylinder 23 detected by the work bench load detector 45 has a predetermined value. When it exceeds, it is activated in response to a control signal from the controller 40. That is, when the leveling device having the above-described configuration is used, when the load detected by the work table load detector 45 is equal to or less than a predetermined value, the hydraulic pump P bypasses the continuous discharge hydraulic booster device 60 and directly hydraulically flows to the leveling cylinder 23. When the load detected by the work bench load detector 45 exceeds a predetermined value, the hydraulic pressure from the hydraulic pump P is amplified by the continuous discharge hydraulic booster device 60 and supplied to the leveling cylinder 23. To perform leveling control. For this reason, even when the load from the work table is large, the leveling control can be performed without any trouble using the small-diameter leveling cylinder 23.
[0024]
Next, a leveling device according to a second embodiment of the present invention will be described with reference to FIG. In this device, the same parts as those in the leveling device shown in FIG. Also in this leveling device, the leveling cylinder 23 is controlled by the leveling control valve 35, but the pump motor unit 90 is disposed in the oil passage 91 from the hydraulic pump P to the leveling control valve 35. The rotation shaft of the pump motor unit 90 is connected to the rotation shaft of the motor generator unit 95.
[0025]
The pump motor unit 90 is driven by the hydraulic pressure supplied from the hydraulic pump P through the oil passage 91 to function as a hydraulic motor that rotates the motor generator 95 to generate electric power, and is driven by the motor generator 95. It functions as a hydraulic pump that amplifies the hydraulic pressure supplied from the hydraulic pump P via the oil passage 91 and supplies the amplified hydraulic pressure to the leveling control valve 35. As can be seen from this, the motor generator 95 has an operation as a generator and an operation as an electric motor.
[0026]
In this leveling device, when the load on the leveling cylinder 23 detected by the work bench load detector 45 is equal to or less than a predetermined value, the hydraulic oil from the hydraulic pump P passes through the pump motor unit 90 and rotates to drive the leveling control. Supplied to the valve 35. That is, when the work bench load is small, the operation control of the leveling cylinder 23 is performed using the hydraulic pressure obtained from the hydraulic pump P as it is. However, at this time, the motor generator 95 is rotationally driven by the pump motor unit 90 to generate electric power, and the battery 47 is charged. That is, energy regeneration is performed to effectively use the energy of the engine E (energy saving).
[0027]
On the other hand, when the load detected by the work bench load detector 45 exceeds a predetermined value, the motor 47 is energized from the battery 47 to function as an electric motor, and the pump motor unit 90 is driven via the oil passage 91. The hydraulic pressure supplied from the hydraulic pump P is amplified and supplied to the leveling control valve 35. As a result, even when the load from the work table is large, the leveling control can be performed without any trouble using the small-diameter leveling cylinder 23.
[0028]
【The invention's effect】
As described above, according to the present invention, the hydraulic pressure amplified by the hydraulic amplifier can be supplied to the leveling cylinder as necessary. For example, when the work bench load is small , the hydraulic pressure from one hydraulic supply means is It can be supplied to the leveling cylinder as it is, and the hydraulic pressure from the hydraulic pressure supply means can be amplified and supplied to the leveling cylinder when the work bench load is large, so that the leveling cylinder can be leveled without increasing the size of the leveling cylinder. Leveling control can be performed without hindrance when the load (load) acting on the cylinder is small (below a predetermined value) or large (when it exceeds a predetermined value). That is, according to the present invention, it is possible to perform leveling control with respect to a work table load larger than the conventional one by using the hydraulic pressure supply means and the leveling cylinder having the same specifications as the conventional one. It is possible to reduce the leveling cylinder without changing the specifications of the hydraulic pressure supply means for the work table load.
[0029]
Also, a continuous load hydraulic booster device is provided in the oil path from the hydraulic pressure supply means to the leveling cylinder, and the oil path from the hydraulic pressure supply means to the leveling cylinder is provided with a work bench load detection means. Can be configured from a bypass oil passage that bypasses the continuous discharge hydraulic booster device and an operation switching valve that switches between an oil passage that passes through the continuous discharge hydraulic booster device . In this case, when the load detected by the work bench load detecting means is below a predetermined value, the operation switching valve switches the oil path from the hydraulic supply means to the leveling cylinder to a bypass oil path that bypasses the continuous discharge hydraulic booster device. Thus , the hydraulic pressure is supplied to the leveling cylinder, and when the load detected by the platform load detection means exceeds a predetermined value, the operation switching valve passes through the oil passage from the hydraulic supply means to the leveling cylinder through the continuous discharge type hydraulic booster device. By switching to the oil passage, the hydraulic oil pressure is amplified by the continuous discharge hydraulic booster device and supplied to the leveling cylinder. In this way, leveling control for a larger platform load than before can be achieved simply by adding a continuous discharge hydraulic booster device, or leveling control can be performed using a smaller leveling cylinder than the conventional for the same platform load. It becomes possible.
[0030]
Further, the hydraulic pressure amplifying device includes a pump motor unit disposed in an oil passage from the hydraulic pressure supply means to the leveling cylinder, and a motor generator unit having a rotation shaft connected to the rotation shaft of the pump motor unit. You can also. In this case, when the load detected by the work table load detecting means is equal to or less than a predetermined value, the pump generator unit is rotated by the hydraulic pressure supplied from the hydraulic pressure supplying means to the leveling cylinder, and power is generated by the motor generator unit. On the other hand, when the load detected by the platform load detecting means exceeds a predetermined value, the motor generator unit is driven, and the pump motor unit amplifies the oil pressure from the oil pressure supplying means on the oil path from the oil pressure supplying means to the leveling cylinder. Supply to the leveling cylinder.
[0031]
By using the leveling device having such a configuration, not only leveling control with respect to a larger platform load than before, but also leveling control using a smaller leveling cylinder than before with respect to the same platform load as before can be performed. When the work bench load is small, the motor generator unit can generate power (energy regeneration) to save energy.
[Brief description of the drawings]
FIG. 1 is a hydraulic circuit diagram showing a configuration of a leveling device according to a first embodiment of the present invention.
FIG. 2 is a front view of an aerial work vehicle having a leveling device according to the present invention.
FIG. 3 is a hydraulic circuit diagram showing a configuration of a continuous discharge hydraulic booster device constituting the leveling device.
FIG. 4 is a hydraulic circuit diagram showing a configuration of a leveling device according to a second embodiment of the present invention.
[Explanation of symbols]
14 Boom 16 Lifting cylinder 21 Work table 23 Leveling cylinder 30 Lifting control valve 35 Leveling control valve 40 Controller 43 Tilt detector 45 Work load detector 60 Continuous discharge type hydraulic booster device 65 Operation switching valve 70 Booster mechanism 78 Double acting control valve 90 Pump motor unit 95 Motor generator P Hydraulic pump E Engine

Claims (2)

A boom disposed at least up and down on the vehicle body, a worktable support member disposed at the tip of the boom so as to be swingable up and down, and a worktable attached to the worktable support member. A leveling device for an aerial work platform,
A leveling cylinder which is expanded and contracted by receiving hydraulic oil supply to swing the worktable support member with respect to the boom;
One hydraulic pressure supply means for supplying hydraulic oil to the leveling cylinder;
A leveling control valve for controlling the hydraulic pressure supply from the hydraulic pressure supply means to the leveling cylinder in accordance with the undulation of the boom, and holding the work table horizontally regardless of the undulation of the boom;
A hydraulic amplifying device for amplifying the hydraulic pressure supplied to the leveling cylinder via the leveling control valve ;
A work table load detecting means for detecting a load acting on the leveling cylinder from the work table;
The hydraulic amplifying device includes a continuous discharge type hydraulic booster device disposed in an oil path from the hydraulic pressure supply means to the leveling cylinder, and an oil path from the hydraulic pressure supply means to the leveling cylinder. An operation switching valve for switching between a bypass oil passage that bypasses the hydraulic booster device and an oil passage that passes through the continuous discharge hydraulic booster device,
Further, when the load detected by the work table load detecting means is less than a predetermined value, the operation switching valve switches the oil path from the hydraulic pressure supplying means to the leveling cylinder to the bypass oil path, whereby the leveling cylinder is hydraulically operated. When the load detected by the platform load detection means exceeds a predetermined value, the operation switching valve passes through the oil passage from the hydraulic pressure supply means to the leveling cylinder through the continuous discharge hydraulic booster device. A leveling device for an aerial work vehicle characterized in that the hydraulic pressure of hydraulic oil is amplified by the continuous discharge hydraulic booster device by switching to an oil passage and supplied to the leveling cylinder. A boom disposed at least up and down on the vehicle body, a worktable support member disposed at the tip of the boom so as to be swingable up and down, and a worktable attached to the worktable support member. A leveling device for an aerial work platform,
A leveling cylinder which is expanded and contracted by receiving hydraulic oil supply to swing the worktable support member with respect to the boom;
One hydraulic pressure supply means for supplying hydraulic oil to the leveling cylinder;
A leveling control valve for controlling the hydraulic pressure supply from the hydraulic pressure supply means to the leveling cylinder in accordance with the undulation of the boom, and holding the work table horizontally regardless of the undulation of the boom;
A hydraulic amplifying device for amplifying the hydraulic pressure supplied to the leveling cylinder via the leveling control valve ;
A work table load detecting means for detecting a load acting on the leveling cylinder from the work table;
The hydraulic amplifying device comprises a pump motor unit disposed in an oil passage from the hydraulic pressure supply means to the leveling cylinder, and a motor generator unit having a rotary shaft connected to the rotary shaft of the pump motor unit. The pump motor unit is rotated by the hydraulic pressure supplied from the hydraulic pressure supply means to the leveling cylinder when the load detected by the work table load detection means is a predetermined value or less, and the motor generator unit generates power. When the load detected by the platform load detection means exceeds a predetermined value, the motor generator unit is driven, and the pump motor unit causes the hydraulic pressure from the hydraulic pressure supply means to reach the leveling cylinder on the oil path. Amplified with the leveling syring Aerial leveling device, wherein the switchable by a signal from the supplied thereby, the worktable load detection as to.

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