JPH10147957A - Acceleration device for construction machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a detecting means to be smoothly set to detect whether a boom cylinder is driven or not, even if there is a difference in machine type conditions such as inexpensive types and different structures of operation lever. SOLUTION: In an acceleration device for a construction machine to perform acceleration increase when a drilling device is driven and to perform acceleration decrease to idling for automatic idling control when it is not driven, if the variation quantity of a boom potentiometer PMI per unit time after the acceleration setting of an acceleration lever 24 is less than a preset value, the rotating number of an engine is set to the idling side and, if it is not less than the preset value, the rotating number of the engine is increased to the present value by the acceleration lever 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accelerator device for a construction machine such as a backhoe or the like, and more particularly, to an automatic rotation of an engine speed to an idling state when a hydraulic actuator is not operated, that is, when no load is applied. The present invention relates to a construction machine equipped with a control for automatically lowering the so-called automatic idle.

[0002]

2. Description of the Related Art A backhoe disclosed in Japanese Patent Application Laid-Open No. 8-158409 is known as one employing an automatic idle. In this device, it is determined whether or not a hydraulic actuator is operating by a pilot pressure. Was performed by the detection of Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 8-67167, information from three potentiometers for detecting the movement of an operating lever for a working device is used.
It was determined whether the hydraulic actuator was moving or not.

[0003]

However, in the case of a model that does not employ a pilot operation structure, for example, a small model or an inexpensive model, the means of the former publication is impossible. In the case of the latter means, an operation lever is used. In a model having a structure in which a control valve is operated mechanically, there is not always an extra space in which a dedicated potentiometer can be additionally set in an operation lever portion, and design difficulty is often involved. Therefore, an object of the present invention is to improve the operation detection means so that it can be set without difficulty even if there is a difference in model conditions such as a low-priced model or a case where the structure of the operation lever portion is different. .

[0004]

[Means for Solving the Problems]

(Configuration) In order to achieve the above object, the present invention provides an operation detecting means for detecting an operation amount of an accelerator operation tool which is manually operated,
Equipped with an operation actuator for driving and operating the engine speed adjusting means and an operation detecting means for detecting whether or not the hydraulic actuator for driving the working device is operating. When the hydraulic actuator is stopped, the engine speed is changed to the idling side. In addition to the operation of the hydraulic actuator, a construction machine accelerator device having an accelerator control means for linking the operation detection means and the operation actuator so as to operate the engine speed to the set value by the accelerator operation tool when the hydraulic actuator is operated. Actuating means is provided with a potentiometer for detecting the movement of the actuator, and when the amount of fluctuation of the potentiometer per unit time after the accelerator setting operation of the accelerator operation tool is less than a predetermined amount, the engine speed is reduced. Operate to idling side, And it is characterized in that it is linked to operate the engine speed set value by the accelerator operation member when it is quantitatively more.

According to the first aspect of the present invention, the operation detecting means for controlling the operation of the automatic idle is constituted by a potentiometer for detecting the movement of the hydraulic actuator. This eliminates the problem that there is no space for disposing the potentiometer, such as mounting the potentiometer, and also allows the potentiometer to be equipped irrespective of the operating means of a working device such as a pilot operated type or an electromagnetic operated type. Therefore,
A small or inexpensive model can be provided with a potentiometer as an operation detecting means, and the mounting place does not have to be troublesome.

[0006] By detecting the movement of the hydraulic actuator, it is possible to more directly detect whether or not the working device is operating. However, there is a slight problem when the hydraulic oil leaks. In other words, when the leak occurs, the working device may move slightly, such as when the boom is gradually lowered, but in that case, the control device determines that the detection value of the potentiometer also fluctuates and the hydraulic actuator is moving, Actually, the engine speed rises to the set value even though the hydraulic actuator is not driven.

Therefore, when the amount of change of the potentiometer per unit time after the accelerator setting operation of the accelerator operation tool is less than a predetermined amount, the engine speed is operated to the idling side, and when the amount of change is more than the predetermined amount. Since it is linked to operate the engine speed to the set value by the accelerator operation tool, the accelerator will not be raised at the time of extremely dull potentiometer reaction due to leak, and when the angle fluctuation per unit time becomes clear, that is, The accelerator is only raised when the hydraulic actuator is driven.

[0008] As a result, the operation detection means having a structure in which the movement of the hydraulic actuator is detected by the potentiometer makes it possible to automatically operate the auto-idle regardless of the type of the operating device of the working device, the size of the working device, or the cost. It is a preferable thing which can be equipped and can solve the new problem of malfunction at the time of leakage due to its structure and can be realized without any inconvenience.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below.
A case of a backhoe as an example of a construction machine will be described with reference to the drawings. FIG. 1 shows a backhoe, 1 is an excavating work device, 2 is a turning table, 3 is a traveling machine stand, 4 is a crawler traveling device, and the excavating work device 1 includes a boom 5, an arm 6, a bucket 7, and the like. It is configured. In this backhoe, a boom cylinder 5c, an arm cylinder 6c,
A load sensing system and an auto idle system are incorporated in a hydraulic circuit for driving an actuator such as a bucket cylinder 7c and a traveling hydraulic motor or a swing cylinder (not shown), and the hydraulic circuit will be described based on the principle diagram shown below.

FIG. 2 shows a principle circuit diagram of a circuit relating to the boom cylinder 5c and the arm cylinder 6c. Reference numeral 8 denotes a variable displacement hydraulic pump driven by an engine 19, and reference numeral 13 denotes a unit time of the hydraulic pump 8. This is a flow rate adjustment mechanism that variably sets the amount of discharge oil per unit. Flow control mechanism 13
Is constituted by an adjustment cylinder 13 composed of a horsepower control cylinder 13A operated by the discharge pressure of the main pump 8 and a flow control cylinder 13B driven by the adjustment pump 18. The flow control mechanism A and the pressure compensation type flow control valve 14 corresponding thereto constitute a load control means A. 9 is a control valve for the boom, 10 is a control valve for the arm, 11 is a compensator for the boom and 12 is a compensator (pressure compensating valve) for the arm, and a throttle valve 9s is provided in the supply-side oil passage in both control valves 9 and 10. , 10s.

Each of the compensators 11 and 12 is located on the lower side of the pressure oil supply to each of the supply side throttle valves 9s and 10s.
In addition, they are arranged on the upstream side of the pressure oil supply to the actuators 5c and 6c. And each compensator 1
Low-pressure-side oil passages 11t and 12t are provided on the downstream side of the pressure oil supply to the actuators 1 and 12 and communicate the upper side of the pressure oil supply to the actuators 5c and 6c with the spring-side oil chambers of the compensators 11 and 12. It is.

[0012] The throttle valve 9s, which is on the upstream side of the pressure oil supply to the compensators 11 and 12, and which is in the supply-side oil passage.
The high-pressure side oil passage 1 that communicates the lower side of the pressure oil supply for 10 s with the non-spring side oil chamber of each of the compensators 11 and 12.
1k and 12k are provided. Each compensator 11,1
2, a constant pressure reducing valve provided with a compression spring 17 for biasing the flow path to the disconnection side, thereby forming an after-orifice type load sensing circuit.

A first low-pressure side oil passage 14t is provided for communicating the spring-side oil chamber 14x of the flow control valve 14 with the lower side of the pressure oil supply to each of the supply-side throttle valves 9s and 10s. A first low-pressure side oil passage 14t communicates with 11t and 12t. Pressure oil supply ports 9p, 10 of each control valve 9, 10
A communication oil passage 15 communicated with p and a non-spring-side oil chamber of the pressure control valve 14 communicate with a dedicated connection oil passage 16. or,
Adjusting cylinder 13 at the time of switching of flow control valve 14
Is supplied by a dedicated adjustment pump 18 driven by the engine together with the hydraulic pump 8.

As shown in FIG. 2, an accelerator lever (an example of an accelerator operating device) 24 for adjusting and setting the engine speed by manual operation, an accelerator adjusting mechanism B for driving and controlling the engine speed and a boom Cylinder 5c
Operation detecting means C for detecting whether or not the hydraulic actuator for driving the excavating work apparatus 1 is operating. When the hydraulic actuator is stopped and there is no load, the engine speed is changed to the idling side and And an accelerator control means D for operating an accelerator adjusting mechanism B such that the engine speed is controlled to a set value by an accelerator lever 24 when the hydraulic actuator is operated.

That is, potentiometers PM1, PM2, and PM3 are provided at the base pivot points of the boom 5, the arm 6, and the bucket link 7R, respectively, and a governor (an example of an engine speed adjusting means) 20 of the engine 19 is provided with a governor lever 21. A geared motor (an example of an operation actuator) 22 for driving and operating the governor lever 21, and a potentiometer (an example of an operation detection means) 25 for detecting an operation position of the accelerator lever 24 are connected to a control device 26 so as to control the accelerator control means D. Is configured. That is,
By operating the hand accelerator lever 24 at the idling position i, the engine speed in the working state (usually often set to the full accelerator position m) is set,
In the working state, the set number of revolutions is maintained, and during non-working (no load), the engine speed is reduced to the idling state while the accelerator lever 24 is kept set at the position m.

The operation detecting means C is composed of three potentiometers PM1, PM2, PM3 for a working device, and a time-measuring operation is performed in accordance with an operation of setting an accelerator from the idling side to the high rotation side. A timing means 27 to be started is provided. When the amount of fluctuation of each of the potentiometers PM1, PM2, PM3 per unit time after the accelerator setting operation of the accelerator lever 24 is less than a predetermined amount, the engine speed is operated to the idling side and is equal to or more than the predetermined amount. Sometimes, all four potentiometers 25, so that the engine speed is controlled to the set value by the accelerator lever 24,
PM1, PM2, PM3, timing means (timer, etc.) 2
7 and the geared motor 22 are linked by a control device 26.

In the case of the boom potentiometer PM1, when the time required for the potentiometer PM1 to move by the angle β is equal to or less than γ, the engine speed is increased to the engine speed as indicated by the accelerator lever 24, and When it takes time, it is controlled to lower to the idling state. At this time, the unit time γ (1 minute to 3 minutes)
The hit angle change β (an example of the above-described predetermined amount), that is, β / γ is larger than the value when the boom 5 descends due to a general leak, and the boom 5 is driven by extending and retracting the boom cylinder 5c. Is set to be smaller than the value at the time of ascending and descending, the engine speed does not increase even if the boom 5 moves down due to the leak, and the auto idle control that matches the actual situation can be performed. . The arm 6 and the bucket 7 are similarly controlled, and a series of control operation flowcharts are shown in FIG. 3 for reference.

In this case, even if the accelerator lever 24 is operated to the high rotation side to start the digging operation, the idling state is maintained for a while, and whether the digging operation device 1 is moved by the driving of the hydraulic actuator is determined. After the elapse of the above-mentioned unit time (1 minute to 3 minutes) required for the determination, the engine speed is increased to the set value for the first time.

The three potentiometers PM1, PM2 and PM3 for the excavating work apparatus 1 are actually provided by
No. 66573 is provided for attitude control, and in the present application, a potentiometer provided in advance is also used for auto idle control so that new components can be reduced and an economical configuration can be achieved. It is. In addition, even when the present invention is applied to a backhoe having a boom offset structure disclosed in Japanese Patent Application Laid-Open No. 8-81980, a plurality of potentiometers provided in an excavation work device are controlled by an automatic idle control for preventing interference between a bucket and an operating unit. It can be used for

[Alternative Embodiment] In the above embodiment, the hydraulic actuator is constituted by the boom cylinder 5c, the arm cylinder 6c, and the bucket cylinder 7c. However, the traveling hydraulic motor and the swing cylinder are also hydraulic actuators. A single hydraulic actuator may be used. Further, the construction of the present invention may be applied to a construction machine such as a crane or a transport vehicle with a working device.

[Brief description of the drawings]

FIG. 1 is a side view of a backhoe.

FIG. 2 is a control system diagram showing the principle of load sensing and auto idle.

FIG. 3 is a view showing a flowchart of an automatic idle control.

[Explanation of symbols]

 5c Hydraulic actuator 20 Engine speed adjustment means 22 Operation actuator 24 Accelerator 25 Operation detection means PM1 Potentiometer C Operation detection means D Acceleration control means

Claims (1)

[Claims] An operation detection means for detecting an operation amount of an accelerator operation tool which is manually operated, an operation actuator for driving and operating an engine speed adjustment means, and whether or not a hydraulic actuator for driving a working device is operated. When the hydraulic actuator is stopped, the engine speed is changed to the idling side, and when the hydraulic actuator is operated, the engine speed is operated to a set value by the accelerator operation tool. An accelerator device for a construction machine comprising accelerator control means for linking the operation detection means and the operation actuator, wherein the operation detection means comprises a potentiometer for detecting the movement of the hydraulic actuator; Per unit time after accelerator set operation of accelerator operation tool When the amount of fluctuation of the potentiometer is less than a predetermined amount set in advance, the engine speed is operated to the idling side, and when the amount is more than the predetermined amount, the engine speed is operated to the set value by the accelerator operation tool. The accelerator device of the construction machine that is linked.