KR20110074007A - System and method for preventing boom of excavator from being taken off - Google Patents

Abstract

PURPOSE: System and method for preventing the boom of an excavator from becoming separated are provided to prevent a boom from becoming separated by appropriately controlling an arm operation and relief pressure when an arm dump operation is done in a state a bucket stands a heavy load. CONSTITUTION: A system for preventing the boom of an excavator from becoming separated comprises a joystick(20), a pressure sensor(30), a reducing valve(40) and an equipment controller(10). The joystick controls an arm. The pressure sensor senses the pressure of a boom cylinder. The reducing valve varies relief pressure. When the sensed pressure arrives at a predetermined pressure, which is determined based on the relief pressure, if the joystick recognizes the opened operation of the arm, then the equipment controller operates the reducing valve. The equipment controller proportionally increases the relief pressure.

Description

Excavator Boom Fall Prevention System and Control Method {SYSTEM AND METHOD FOR PREVENTING BOOM OF EXCAVATOR FROM BEING TAKEN OFF}

The present invention is to provide a system and method for eliminating the risk of work by preventing the unintentional boom falling out according to the position and workload of the front when the construction equipment such as an excavator is arm dumping. It is about.

In the field of excavators, techniques are known for setting the main relief pressure below a certain value for fuel economy savings. However, in a situation where a large flow rate is required, for example, a worker suddenly pulls out a work load of a workpiece placed in a bucket after an excavation work, and the front is struck down to collide with the truck or cause injury.

The boom may fall out depending on the position of each part of the front. If the angle between the boom and the arm is narrow (e.g. within 90 degrees) during excavation, the boom does not sag even if the workpiece is lifted. When the truck is lowered (when the truck is loaded), the angle of the boom and the arm widens (for example, more than 90 degrees and less than 180 degrees), so that the pressure formed in the boom cylinder exceeds the relief pressure, and the boom cylinder cannot be sustained and falls out. The situation that sag down occurs.

In addition, such a boom falling out phenomenon may occur when the excavator is limited in the amount of work put in the bucket.

In order to prevent such a problem, according to the present invention, when the operator performs an arm dump operation or other operation in a state in which a heavy load is applied to the bucket, the boom pulling out phenomenon does not occur by appropriately controlling the arm operation and the relief pressure.

Excavator boom fall prevention system of the present invention, the joystick for steering the arm, the pressure sensor for sensing the pressure of the boom cylinder, the relief pressure control electromagnetic proportional pressure reducing valve for varying the relief pressure, the sensed pressure is based on the relief pressure When it reaches the set pressure is set to, the joystick is operated to extend the arm, when operating the relief pressure control electronic proportional pressure reducing valve includes an equipment controller for proportionally increasing the relief pressure.

The system of the present invention further includes an arm operating spool control electromagnetic proportional damping valve for adjusting the opening and closing amount of the spool for operating the arm, and a main control valve controller for controlling the arm operating spool control electromagnetic proportional pressure reducing valve, and relief pressure regulation. When the amount of increase in the relief pressure caused by the operation of the solenoid pressure reducing valve reaches the first pressure value set on the basis of the maximum increase in the relief pressure, the equipment controller changes the push action control diagram to signal the main control valve controller. The main control valve controller controls the arm motion spool control proportional damping valve based on the modified arm motion control diagram to slow the motion of the arm.

In addition, the system of the present invention further comprises a pump proportional pressure reducing valve for adjusting the pressure of the pump, wherein the amount of increase in the relief pressure by the operation of the relief pressure control electromagnetic proportional pressure reducing valve is set based on the maximum increase value of the relief pressure When the pressure value is reached, the equipment controller controls the pump proportional pressure reducing valve so that the pump outputs the minimum flow rate.

In addition, the system of the present invention, when the increase in the relief pressure by the operation of the relief pressure control electromagnetic proportional pressure reducing valve reaches the second pressure value set on the basis of the maximum increase value of the relief pressure, the equipment controller to the main control valve controller By sending a signal to control the arm operation spool control electromagnetic proportional damping valve to stop the arm unfolding operation, and at the same time may further include a warning means for sending a warning signal to the operator.

On the other hand, the excavator boom fall prevention control method of the present invention, the step of sensing the pressure of the boom cylinder, and recognizes that the joystick is operated to extend the arm when the sensed pressure reaches the set pressure set based on the relief pressure If any, increasing the relief pressure proportionally.

In addition, the control method of the present invention, when the amount of increase in the relief pressure by the operation of the relief pressure control electromagnetic proportional pressure reducing valve reaches the first pressure value set on the basis of the maximum increase value of the relief pressure, Altering the control diagram to slow the arm operation and allowing the pump to output the minimum flow rate may be further included.

In addition, the control method of the present invention, when the increase amount of the relief pressure by the operation of the relief pressure control electromagnetic proportional pressure reducing valve reaches the second pressure value set on the basis of the maximum increase value of the relief pressure, stopping the arm unfolding operation The method may further include sending a warning signal to the worker.

According to the present invention, by controlling the arm operation and the relief pressure appropriately to prevent the boom falling out to eliminate the risk factors that can occur in operation, through the optimum control to reduce the durability of parts due to the use of high pressure during the operation Minimize and maximize fuel efficiency through pump control.

In the system according to the present invention, the relief pressure increase, arm operation control, pump flow rate control, and alarm generation are performed in order to prevent the boom from falling off. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. do.

One. Relief  Pressure increase

Pressure of the boom cylinder is sensed by the pressure sensor 30 during operation of the equipment. If the sensed pressure reaches the set pressure, the equipment controller 10 checks the operating state of the joystick 20. Here, the set pressure is preferably set to a value based on the relief pressure, that is, a value corresponding to a predetermined ratio of the relief pressure, for example, it may be set to 97% of the relief pressure. For example, if the relief pressure of the equipment is around 350 bar, the set pressure can be 339.5 bar, 97% of the relief pressure.

At this time, if the joystick 20 operates to straighten the arm, there is a possibility of causing the boom to fall out. The equipment controller 10 controls the relief pressure to be greater than the normal relief pressure (for example 350 bar) by sending a signal to the relief pressure regulating Electronic Proportional Pressure Reduce (EPPR) valve 40. do. That is, the hydraulic pressure is additionally applied to the spring (not shown) side of the relief valve 40 so that the relief pressure of the relief valve 40 is increased by the sum of the existing spring elasticity and the hydraulic pressure further. However, the method of increasing the relief pressure of the relief valve is not limited thereto, and various methods may be used, such as using a method of changing the spring elasticity of the relief valve 40.

However, set the maximum increase of the relief pressure so that the relief pressure is no longer increased. The maximum increase in the relief pressure is usually set at about 20 to 30 bar, so the relief pressure can be increased up to 380 bar, for example if the relief pressure of the pre-regulator equipment is 350 bar.

When the pressure sensed by the pressure sensor 30 exceeds 368 bar, which corresponds to 97% of the maximum value of 380 bar, the relief pressure is fixed at 380 bar and no longer increases.

Due to such an increase in the relief pressure, the pressure formed in the boom cylinder does not exceed the relief pressure, thus suppressing occurrence of the boom phenomenon.

2. Arm motion control

If the increase in the relief pressure by the operation of the relief pressure control electromagnetic proportional pressure reducing valve 40 reaches the first pressure value set on the basis of the maximum increase value of the relief pressure, further measures are required. This controls the slow motion of the arm when extending the arm.

Here, if the relief pressure is increased by a certain ratio of the maximum increase value of the relief pressure, for example, 70% of the maximum increase value of the relief pressure, the increase amount of the relief pressure at this time is set as the first pressure value. Therefore, if the maximum increase value of the relief pressure is set to 30 bar, 70% of 30 bar, that is, 371 bar, which is an increased relief pressure of about 21 bar, the arm motion is controlled slowly.

In addition, when the amount of increase in the relief pressure by the operation of the relief pressure control electromagnetic proportional pressure reducing valve 40 reaches the second pressure value set on the basis of the maximum increase value of the relief pressure, the arm operation is stopped. Here, the second pressure value is set to a pressure higher than the first pressure value, and if the relief pressure is increased by a certain ratio, for example, 95%, of the maximum increase value of the relief pressure, the increase amount of the relief pressure at this time is set to the second pressure value. Set to. Therefore, if the maximum increase in the relief pressure is set to 30 bar, the arm motion is stopped when 958.5 of 30 bar, that is, 378.5 bar, which is increased by about 28.5 bar.

Operation of each component according to the arm motion control is as follows.

In the case of employing the electric joystick 20 and the electronic main control valve (MCV) controller 60, the spool opening and closing amount according to the joystick 20 operation amount is controlled by the equipment controller 10 and the main control valve controller 60. Is saving. Spool control for each of the arm, the boom and the bucket controls one spool using two spool control electromagnetic proportional pressure reducing valves 70. In other words, the amount of current supplied to one of the spool control electromagnetic proportional pressure reducing valves 70 is adjusted when the arm is unfolded, and the amount of opening of the spool is adjusted. The amount of closing current of the spool is controlled by controlling the amount of current input to 70. A spring is attached to both sides of the spool, and the amount of opening and closing of the spool is determined by comparing the force of the spring with the amount of current input to the spool control electromagnetic proportional pressure reducing valve 70.

Spool opening and closing control according to the operation of the joystick 20 will follow the control diagram. 2A illustrates a typical control diagram for adjusting the stroke of the spool according to the signal coming out of the joystick 20.

If the increase in the relief pressure due to the operation of the relief pressure regulating electromagnetic proportional pressure reducing valve 40 reaches a certain ratio of the variable maximum value (the maximum increase value of the relief pressure), for example, 70% of the maximum increase value of the relief pressure. When the equipment controller 10 changes the control diagram for the straightening operation, which is previously stored, the arm operation is changed to be slow, and the signal is transmitted to the main control valve controller 60. In other words, the previously stored control diagram is changed to a control diagram set to open more slowly and less spools as shown in FIG. Then, the main control valve controller 60 controls the arm operation spool control electromagnetic proportional pressure reducing valve 70 to narrow the opening amount of the spool so that the arm operation is slow.

On the other hand, when the amount of relief pressure increase by the relief pressure regulating electromagnetic proportional pressure reducing valve 40 reaches a certain ratio of the maximum variable value (maximum increase value of the relief pressure), for example, 95% of the maximum increase value of the relief pressure, The controller 10 sends a signal to the main control valve controller 60 to stop the straightening operation to completely stop the arm operation.

3. Pump Electronic proportional decompression  Valve control

Simultaneously with the change of the control diagram indicating the spool opening and closing amount according to the joystick 20 operation amount, the equipment controller 10 also controls the pump electromagnetic proportional pressure reducing valve 50 to adjust the pump flow rate to the minimum. A slower arm speed due to a change in the control diagram eliminates the need for a high pump flow rate, while reducing the pump flow rate can minimize engine load and further reduce fuel economy.

Such a flow rate control of the pump may further improve energy efficiency when a pump for providing a flow rate preferentially to the boom and a pump for providing a flow rate preferentially to the arm are provided separately. In other words, if it is necessary to supply the flow rate to both the boom and the arm with a single pump, the above-mentioned reduction of flow rate may affect the boom drive and other work devices. However, if the pumps are separated as described above, When applied, the energy consumption of the arm drive pump can be offset by the increase in the energy consumed by the boom drive pump. Typically, excavators are equipped with arm 1 speed / 2 speed spools and boom 1 speed / 2 speed spools, each of which is supplied with a flow rate by a plurality of pumps. In this case, the above-described energy efficiency can be expected by separating and installing the arm 1-speed spool pump and the boom 1-speed spool pump and reducing the flow rate of the arm 1-speed spool pump.

4. Alarm occurrence

When the amount of increase in the relief pressure due to the operation of the relief pressure regulating electromagnetic proportional pressure reducing valve 40 reaches the second pressure value set on the basis of the maximum increase value of the relief pressure, the equipment controller 10 receives the warning means 80. Inform workers of warning signs that indicate a dangerous condition. As the warning means 80, a warning buzzer or a warning lamp may be considered.

The embodiment of the present invention has been described above. However, the protection scope of the present invention is defined based on the appended claims, and is not limited to the above-described embodiment. The protection scope of the present invention extends to the equivalent technical scope that can be sufficiently understood by those skilled in the art.

1 is a schematic diagram of a system of the invention

Figure 2 is a control diagram for the unfolding operation of the joystick in the system of the present invention

BRIEF DESCRIPTION OF THE DRAWINGS

10: equipment controller

20: joystick

30: boom cylinder pressure sensor

40: relief pressure regulating electromagnetic proportional pressure reducing valve

50: pump proportional pressure reducing valve

60: main control valve controller

70: spool control proportional pressure reducing valve

80: warning

Claims (8)

Joystick to control the arm, Pressure sensor for sensing the pressure of the boom cylinder, Relief pressure regulating electromagnetic proportional pressure reducing valve which varies relief pressure, When the sensed pressure reaches the set pressure set on the basis of the relief pressure, when the joystick is recognized to operate to extend the arm, the relief pressure regulating electromagnetic proportional pressure reducing valve is operated to proportionally increase the relief pressure. Excavator boom fallout system with machine controller. The method according to claim 1, And a main operation valve controller for controlling the arm operation spool control electromagnetic proportional pressure reducing valve for adjusting the opening and closing amount of the spool for operating the arm, and the arm operation spool control electromagnetic proportional pressure reducing valve, Relief pressure control When the increase in the relief pressure by the operation of the electromagnetic proportional pressure reducing valve reaches the first pressure value set on the basis of the maximum increase value of the relief pressure, the equipment controller changes the unfolding operation control diagram to change the main control. Signaling to the valve controller, wherein the main control valve controller controls the arm motion spool control proportional damping valve based on the modified arm motion control diagram to slow the motion of the arm. The method according to claim 2, Further comprising a pump proportional pressure reducing valve for adjusting the pressure of the pump, Relief pressure control When the increase in the relief pressure by the operation of the electromagnetic proportional pressure reducing valve reaches the first pressure value set based on the maximum increase value of the relief pressure, the equipment controller controls the pump proportional control pressure reducing valve so that the pump A boom pull out prevention system to output the minimum flow rate. The method according to claim 2 or 3, Relief pressure control When the increase in the relief pressure by the operation of the electromagnetic proportional pressure reducing valve reaches the second pressure value set on the basis of the maximum increase in the relief pressure, the equipment controller sends a signal to the main control valve controller to arm operation. The spool control excavator proportional damping valve to stop the arm unfolding operation. The method according to claim 2 or 3, Relief pressure control Excavator boom prevention further comprising a warning means for sending a warning signal to the operator when the increase in the relief pressure by the operation of the electromagnetic proportional pressure reducing valve reaches a second pressure value set based on the maximum increase value of the relief pressure system. Sensing the pressure of the boom cylinder; And recognizing that the joystick is operated to straighten the arm when the sensed pressure reaches a set pressure set based on the relief pressure, and proportionally increasing the relief pressure. The method according to claim 6, Relief pressure adjustment When the amount of relief pressure increase by the operation of the proportional pressure reducing valve reaches the first pressure value set on the basis of the maximum increase value of the relief pressure, the control curve for the unfolding operation of the joystick is changed to change the arm motion. Excavator boom fall prevention control method further comprising the step of slowing. The method according to claim 6 or 7, When the increase in the relief pressure by the operation of the relief pressure control electromagnetic proportional pressure reducing valve reaches the first pressure value set on the basis of the maximum increase value of the relief pressure, the pump further comprises the step of outputting a minimum flow rate, Relief pressure control when the increase in the relief pressure by the operation of the electromagnetic proportional pressure reducing valve reaches a second pressure value set on the basis of the maximum increase value of the relief pressure, further comprising the step of stopping the arm extension operation Prevention control method.

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