JPH08100802A - Hydraulic power unit auto accelerator - Google Patents

Abstract

(57) [Summary] [Purpose] The flow rate required for each operation of the hydraulic actuator.
Supply hydraulic oil that matches the pressure. The auto accelerator device 20 includes a detection means 21 for detecting which of a plurality of operations the hydraulic actuator can perform, and a flow rate of hydraulic oil necessary for the operation detected by the detection means 21. The controller 23 controls the operation (accelerator 23) of the drive means (engine) 12 according to the pressure.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic power unit for supplying hydraulic oil to a hydraulic operating device such as a boom, and more particularly to an automatic accelerator device for controlling drive means for driving a hydraulic pump in the hydraulic power unit. .

[0002]

2. Description of the Related Art Booms (hydraulic actuating devices) for lifting a load or moving up and down a work table are attached to a crane vehicle and an aerial work vehicle. A hydraulic cylinder (a hoisting cylinder) that extends and contracts while supporting the load of the entire boom and hoists the boom is attached between the boom and the vehicle body. Further, the boom has a built-in hydraulic cylinder (extendable cylinder) that extends and retracts the tip boom in a telescopic manner with respect to the base boom while supporting the load of the tip boom.

As described above, the boom performs a plurality of operations such as an elevating operation, a falling operation, an extending operation and a contracting operation by supplying hydraulic oil to each hydraulic cylinder, and each boom is supplied to the hydraulic cylinder. The hydraulic oil flow rate and pressure required to be different are different. For example, comparing the elevating operation and the extending operation, the hydraulic oil flow rate required for the telescopic cylinder is higher due to the relationship with the required operating speed, but the difference in the supporting load The hydraulic pressure required for the undulating cylinder is higher. Also, comparing the elevating / extending operation and the fall / shrink operation, in the latter case, the amount of natural drop due to the load of the boom (tip boom) is added, so the hydraulic oil flow rate and pressure are lower than in the former case. Is enough.

A hydraulic power unit for supplying hydraulic oil to each hydraulic cylinder includes a hydraulic pump for discharging hydraulic oil, an engine for driving the hydraulic pump, and an electric motor (both are driving means). In some cases, an auto accelerator device for controlling the operation of the engine or the like is provided. This auto accelerator system discharges a large flow rate or high pressure hydraulic oil from the hydraulic pump by fully opening the accelerator opening of the engine or maximizing the electric power supplied to the electric motor when the boom is operating, while not operating the boom. Occasionally, the accelerator opening is fully closed or the supplied power is minimized to suppress wasteful fuel / power consumption and noise generation.

[0005]

However, in the conventional auto accelerator device, when the boom is operated,
The problem is that energy saving and noise suppression measures are insufficient because the accelerator opening of the engine is fully opened or the electric power supplied to the electric motor is maximized regardless of the hydraulic oil flow rate and hydraulic pressure required for each operation. was there. Also, even if a small flow rate of hydraulic oil is sufficient as in the case of boom slumping / reducing operation, discharging a large flow rate of hydraulic oil from the hydraulic pump will increase the oil temperature, which is not desirable. There is also.

The present invention has been made in view of the above problems, and provides an automatic accelerator device for causing a hydraulic power unit to supply hydraulic oil corresponding to the flow rate and pressure required for each operation of the hydraulic operating device. It is intended to be provided.

[0007]

In order to achieve the above-mentioned object, the auto accelerator system of the present invention comprises a detection means for detecting which of a plurality of operations the hydraulic actuator can perform, And a controller that controls the operation of the drive means in accordance with the hydraulic oil flow rate and pressure necessary for the operation detected by the detection means.

Specifically, when the drive means is an engine, the controller controls the accelerator opening degree of the engine, and when the drive means is an electric motor, the controller supplies the electric power supplied to the electric motor. Control.

[0009]

In such an automatic accelerator device, for example,
An operation for controlling the operation of the hydraulic operating device is detected by the detecting means. Then, when the detected operation, that is, both the hydraulic oil flow rate and the hydraulic pressure necessary for the operation are large, the controller sets the accelerator opening degree of the engine or the electric power supplied to the electric motor to a large value. If the required hydraulic oil flow rate and hydraulic pressure are both low, set the accelerator opening and supply power to small values. In addition, the required hydraulic oil flow rate
When either one of the hydraulic pressures is large, the accelerator opening degree or the supplied power is set to a medium level. By finely controlling the operation of the drive means in accordance with the required hydraulic oil flow rate and hydraulic pressure for each operation of the hydraulic actuator, wasteful fuel consumption and unnecessary noise can be suppressed as much as possible. At the same time, it is possible to prevent the oil temperature from rising excessively.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. First, FIG. 1 shows an aerial work vehicle equipped with an automatic accelerator device for a hydraulic power unit according to the present invention. The aerial work vehicle 1 is configured with a truck as a base, and a swivel base 3 which is capable of horizontally swiveling with respect to the vehicle body 2 is attached to a rear portion of the vehicle body 2. A boom 4 is attached to the upper part of the swivel base 3. The boom 4 includes a base boom 4a pivotally attached to the swivel 3 so as to be up and down, an intermediate boom 4b movably inserted in the base boom 4a in the longitudinal direction, and a longitudinal boom in the intermediate boom 4b. It is configured to be telescopically expandable and contractable from the tip boom 4c inserted so as to be movable in any direction.

A hydraulic hoisting cylinder 5 is mounted between the base boom 4a and the swivel base 3, and the boom 4 is hoisted and driven by the hoisting cylinder 5. A hydraulic telescopic cylinder 6 is built in the boom 4, and the boom 4 is telescopically driven by the telescopic cylinder 6.

A workbench bracket 7a is attached to the tip of the tip boom 4c. This work table bracket 7
The a is held substantially vertically by a leveling device (not shown) regardless of the up and down state of the boom 4. A workbench 7b is attached to the workbench bracket 7a so as to be vertically slidable. This workbench 7b is a workbench bracket 7
The hydraulic slide cylinder 8 built in a is slid up and down with respect to the workbench bracket 7a.

An operating device 9 for controlling the operation of the swivel base 3 and the boom 4 is attached to the workbench 7b.
From this operating device 9, the boom 4 can be raised, lowered, extended,
An operation signal is output according to an operation corresponding to reduction and slide up / down of the workbench 7b. According to the aerial work vehicle 1 configured as described above, an operator (not shown) who is on the workbench 7b controls the operation of the boom 4 and the workbench 7b through the operation of the operation device 9, and the workbench 7b is operated. It is possible to move to any height with 7b.

A hydraulic power unit 10 for supplying hydraulic oil to the undulating cylinder 5 and the telescopic cylinder 6 is attached to the vehicle body 2. The hydraulic power unit 10 will be described below with reference to FIG. The hydraulic power unit 10 includes a hydraulic pump 11, an engine 12 that rotationally drives the hydraulic pump 11, and an auto accelerator device 20 of the present invention. Hydraulic pump 11
Is the suction of the hydraulic oil stored in the oil tank 13.
Discharge. The hydraulic oil discharged from the hydraulic pump 11 is supplied to a control valve (not shown) that controls the supply and discharge of the hydraulic oil to the undulating cylinder 5 and the telescopic cylinder 6. The output shaft of the engine 12 is directly connected to the input shaft of the hydraulic pump 11, and drives the hydraulic pump 11 at the same rotation speed as the rotation speed of the engine 12.

The automatic accelerator device 20 includes an operation detector 2
1, a controller 22, and an accelerator solenoid 23. The operation detector 21 is provided for each operation of the operation device 9 (that is, the operation of the boom 4 and the workbench 7b), and receives the operation signal output from the operation device 9 and outputs a detection signal.

When a detection signal is input from any of the operation detectors 21, the controller 22 outputs an excitation signal having a magnitude corresponding to the operation indicated by this detection signal. Here, the magnitude of the excitation signal corresponding to each operation, that is, the accelerator opening degree of the engine 12, is previously set to the boom 4 or the workbench 7.
It is set and stored in the memory of the controller 22 so as to correspond to the hydraulic oil flow rate and pressure required for each operation of b. Table 1 shows the hydraulic oil flow rate and the hydraulic oil pressure required for each operation, and the accelerator opening corresponding thereto.

[0017]

[Table 1]

For example, when raising the boom 4, the required flow rate is 45ι (liter) / min. And the required hydraulic pressure is 175 kg / cm ² . The accelerator opening is set to be fully open in order to discharge the hydraulic oil having such a flow rate and pressure to the hydraulic pump 11. Also,
When the boom 4 is extended, the required flow rate is 60ι / mi
n. And the required hydraulic pressure is 100 k
g / cm ² is relatively small. In order to discharge the hydraulic oil having such a flow rate and pressure to the hydraulic pump 11, the accelerator opening is set to 3/4 of full opening.

When the boom 4 is contracted, the required flow rate is 4
0ι / min. Although there is not much difference from the time of erecting operation, the required pressure is 40 kg / cm ² , which is considerably smaller than that at elevating operation.
In order to discharge the hydraulic oil having such a flow rate and pressure to the hydraulic pump 11, the accelerator opening is set to 1/2 of the full opening. Further, both the required flow rate and pressure are extremely small, such as when the work table 7b slides up and down (required flow rate 6 to 10ι / min., Required hydraulic pressure 5 to 2).
0 kg / cm ² ), the accelerator opening is 1/4 of the full opening
It is set to ~ 1/3. When the detection signal is not input from any of the operation detectors 21, the excitation signal is not output from the controller 22.

The accelerator solenoid 23 changes the accelerator opening degree of the engine 12 between a substantially fully closed state and a fully open state according to the magnitude of the excitation signal output from the controller 22. When the accelerator solenoid 23 is not excited and the accelerator opening is in the fully closed state, the engine 12 is in the idling state.

Next, the operation of the hydraulic power unit 10 thus constructed will be described. Before the work is started (when the boom 4 is stored), the engine 12 is in the idling state (the rotation speed is about 400 rpm) as described above. Therefore, the fuel is not wastefully consumed and noise is hardly generated.

When a raising operation is performed in the operating device 9, a detection signal is input from the corresponding operation detector 21 to the controller 22. The controller 22 sends an excitation signal corresponding to the raising operation to the accelerator solenoid 23 to fully open the accelerator opening of the engine 12. As a result, hydraulic oil having a sufficient flow rate and pressure is supplied to the hoisting cylinder 5, and the boom 4 is hoisted at a required speed. At this time, the rotation speed of the engine 12 is about 2,000 r.p.
m. Further, when the extension operation is performed in the operating device 9, the accelerator opening is reduced to 3/4 of the full opening, and fuel consumption and noise are slightly suppressed. The engine 12
The rotation speed of is about 2,000r.pm, which is the same as when elevating.

When the slide 4 is operated to make fine adjustments to the height of the workbench 7 when the boom 4 is in an arbitrary undulating / extending state, the accelerator opening is reduced to 1/3 of the fully open state. As a result, the engine speed also drops significantly (about 600 to 800 rpm). As a result, fuel consumption and noise generation can be minimized while smoothly operating the slide cylinder 8.

After the work is completed, when the boom 4 is retracted to perform the contraction operation or the fall operation, the accelerator opening becomes 1/2 of the full opening, and the hydraulic oil having a smaller flow rate and pressure than the extension / elevation operation is used. Is supplied to the extension cylinder 6 and the undulation cylinder 5, and the engine speed also becomes low (about 1200 to 1400 rpm). Therefore, the boom 4 can be stored with less fuel consumption and less noise than when the extension / elevation operation is performed.

In the above embodiment, the case where the engine is used as the driving means has been described, but the auto accelerator device of the present invention can be applied to the case where the electric motor is used as the driving means. In this case, the controller controls the electric power (current) supplied to the electric motor to suppress the wasteful power consumption of the battery.

[0026]

As described above, in the auto accelerator system of the present invention, the operation of the hydraulic actuating device which is about to be performed is detected, and the auto-actuating device is finely adjusted according to the flow rate and the pressure of the hydraulic oil necessary for this operation. The operation of the hydraulic pump drive means is controlled. For this reason, when using this auto accelerator device, the accelerator opening degree of the engine is fully closed when the hydraulic operating means is not operated, and the accelerator opening degree is fully opened when the hydraulic operating means is operated. It is possible to minimize wasteful fuel consumption and unnecessary noise generation, and prevent an increase in oil temperature due to excessive supply of hydraulic oil.

[Brief description of drawings]

FIG. 1 is a side view of an aerial work vehicle equipped with an automatic accelerator device for a hydraulic power unit according to the present invention.

FIG. 2 is a configuration diagram of the hydraulic power unit (including an automatic accelerator device).

[Explanation of symbols]

 4 boom 5 undulating cylinder 6 telescopic cylinder 8 slide cylinder 9 operating device 12 engine 21 operation detector 22 controller 23 accelerator solenoid

Claims (3)

[Claims] 1. A hydraulic power unit equipped with a hydraulic operating device for performing a plurality of operations having different required hydraulic oil flow rates and pressures, the hydraulic pump discharging the hydraulic oil, and a drive means for driving the hydraulic pump. Of the plurality of operations, the detection means for detecting which of the plurality of operations is to be performed, and the drive means according to the hydraulic oil flow rate and the pressure necessary for the operation detected by the detection means. And a controller for controlling the operation of the hydraulic power unit. 2. The automatic accelerator device for a hydraulic power unit according to claim 1, wherein the drive means is an engine, and the controller controls an accelerator opening degree of the engine. 3. The automatic accelerator device for a hydraulic power unit according to claim 1, wherein the drive means is an electric motor, and the controller controls electric power supplied to the electric motor.