KR101500724B1 - An hydraulic apparatus for excavators - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic device for an excavator, which prevents unnecessary movement of a vehicle revolving body during an excavating operation of an excavator, thereby increasing excavation force and energy efficiency, The present invention relates to a hydraulic device capable of preventing wear of excavator parts, which may occur due to lateral loads.

Excavator, Hydraulic unit, Swing

Description

AN HYDRAULIC APPARATUS FOR EXCAVATORS

The present invention relates to an excavator hydraulic device, and more particularly to a hydraulic excavator having a structure in which an operator unintentionally operates a joystick in an oblique direction while a driver operates a joystick lever to prevent an unnecessary lateral load from rotating due to rotation of the upper revolver And more particularly to an improved hydraulic device for an excavator.

Generally, an excavator is provided with a front work device such as a boom, an arm, a bucket, or the like on an upper revolving structure and performs a front work such as an excavation work or a flat work using the work device, Perform the same task.

The excavator has two joysticks (L, R) as shown in FIG. 1, and operates the two joysticks (L, R) of the driver to operate the working device and the upper revolving body. Here, the joystick L on the left side of the normal driver controls the operation of the arm cylinder and the swing motor, and the joystick R on the right side of the driver mainly controls the operation of the boom cylinder and the bucket cylinder.

More specifically, the operation of the arm cylinder is mainly performed by the front-rear operation of the driver's left joystick L, the operation of the swing motor is mainly performed by the left and right manipulation of the driver's left joystick L, The operation of the bucket cylinder is mainly performed by the front and rear operation of the driver's right joystick R and the operation of the bucket cylinder is mainly performed by the left and right operation of the driver's right joystick R. [

As an example of the circuit diagram of the joystick, there is a circuit diagram shown in Fig.

However, as shown in FIG. 2A, the joystick of the excavator is not precisely divided into front, rear, left, and right, and is often operated in an oblique direction as shown in FIG. 2B. Generally, the joystick of the excavator is designed to be able to operate the slanting line. The driver of the excavator intentionally or unconsciously manipulates the joystick in an oblique direction as shown in FIG. 2B.

However, there is no problem in operating the joystick in the oblique direction if necessary, but there is a problem in operating the joystick in the diagonal direction even when the oblique direction of the joystick is not required.

For example, in order to carry out a series of excavation operations, for example, excavation and swing, and a cargo operation, a combined operation of the work devices is required. In this case, the operator must operate the joystick in diagonal directions do. However, it is not necessary to operate the swing motor because only the arm cylinder and / or the bucket cylinder are operated when the digging operation is performed. Therefore, it is not necessary to operate the joystick in the diagonal direction when the digging operation is performed, but the driver may operate the joystick by mistake or unconsciously in the oblique direction to operate the swing motor.

3 and 4, in the hydraulic circuit of the conventional excavator, when the joystick 1 is operated in the diagonal direction, particularly when the joystick L on the left side of the driver is operated in the oblique direction, The swing motor 8 is rotated by the operation of the swing motor 8 along with the extension / contraction operation of the swing arm 7.

5A, when the driver unintentionally or unintentionally operates the left joystick L in the oblique direction even though the left joystick L is operated for the excavation operation, the bucket receives the excavating force Fa, And the lateral rotational force Fb due to the operation of the swing motor is applied at the same time.

If a lateral rotational force Fb acts on the excavator during the excavation work, for example, in the state where the bucket is infiltrated into the ground for excavation, a side load is applied to the excavator component and the impact is applied to the components, In severe cases, the boom, the arm, or the parts attached to the boom or the arm may be distorted.

In addition, as shown in FIG. 5B, the excavator force does not act as excavation force, but a part of the force acts as a rotational force, resulting in loss of excavator force, resulting in energy loss.

In addition, when the above-described loss of force occurs, the weight of the excavator may have to be increased for sufficient excavation force, which may also hinder the lightening of the excavator.

However, there is a problem in that it is difficult to accept a request for the driver to always manipulate the joystick in a precise manner

Accordingly, the present invention is conceived to solve the problem in the case where the driver operates the joystick unnecessarily unnecessarily unnecessarily obliquely or unconsciously during operation of the excavator as described above. In the section where the excavation maximum load is applied, A hydraulic device for an excavator improved in structure to prevent an excessive load from being applied to an excavator by stopping the swing function.

In order to achieve the above-mentioned object, the present invention is characterized in that the control valve unit is operated by operation of the joysticks (L, R), and the hydraulic oil discharged from at least one hydraulic pump is used to drive the arm cylinder, the bucket cylinder, A hydraulic device for an excavator, which selectively operates the swing motor to limit the swing of the excavator swing body selectively.

According to the present invention, the hydraulic device for an excavator basically comprises at least one hydraulic pump (20, 21); A joystick (100) for generating an operation signal for operating the arm cylinder (33), the boom cylinder, the bucket cylinder and the swing motor (48); And the operating oil discharged from the at least one hydraulic pump (20, 21) is supplied to the arm cylinder (33), the boom cylinder, the bucket cylinder and the swing motor (48) in response to the operation signal generated by the joystick A connecting line 13 for connecting the crowd pilot line 11 for operating the arm cylinder 33 and the crowd pilot line 12 for operating the bucket cylinder; A first pressure sensor (15) installed at the connection line (13) for sensing at least one of the pilot pressure for operating the arm cylinder and the pilot pressure for operating the bucket cylinder; And two second pressure sensors (22, 22) installed in hydraulic lines (31, 32) of hydraulic oil discharged from the at least one hydraulic pump (20, 21) and sensing the pressure of hydraulic oil discharged from the hydraulic pumps , 23); A displacement sensor 34 for sensing the extension length of the arm cylinder 33; A shut-off valve (47) installed on the left and right pilot lines (45, 46) for operating the swing motor and capable of opening and closing the left and right pilot lines (45, 46) for operating the swing motor; And a control unit (40) for controlling the shutoff valve (47) in response to signals provided from the first pressure sensor (15), the second pressure sensor (22, 23) and the displacement sensor (34) .

When the pressure of the pilot lines 11 and 12 sensed by the first pressure sensor 15 is equal to or higher than the reference pressure A, the controller 40 controls the first and second pressure sensors 22 and 23 When the discharge pressure of the sensed operating fluid is equal to or higher than the reference pressure B and when the extension length of the arm cylinder 33 sensed by the displacement sensor 34 is in the reference length range C, So that the left and right pilot lines 45 and 46 for swing motor operation can be blocked.

According to an embodiment of the present invention, a shuttle valve 14 may be installed in the connection line 13. In this case, the first pressure sensor 15 is connected to the shuttle valve 14, Pressure and pilot pressure for bucket cylinder operation can be detected.

According to another embodiment of the present invention, the shutoff valve 47 may be a solenoid valve.

In the meantime, according to another example of the present invention, the reference pressure A in the first pressure sensor 15 is set such that the crowd-side flow path of the arm cylinder 33 or the crowd- Can be defined as the pressure value applied to the pilot lines (11, 12) between the open ranges.

The reference pressure B in any one of the two second pressure sensors 22 and 23 may be set to a pressure value corresponding to 70% or more of the optimum maximum discharge pressure of the pump .

Finally, the reference length range C of the arm cylinder 33 can be defined as a range corresponding to 40% to 90% of the maximum extension length of the arm cylinder.

In the hydraulic apparatus for an excavator according to the present invention, the swing motion of the swivel is suppressed in an excavation operation section in which a very large excavation force is applied, so that the excavator driver mistakenly or unconsciously manipulates the joystick to rotate the joystick lever, It is possible to prevent the swivel body from rotating even if it is operated to a possible position. When such a hydraulic device is applied, unnecessary rotation of the swivel body is suppressed, unnecessary lateral force is not applied to the bucket, so that the excavating force can be increased and the durability of the parts related to the excavator can also be maintained. In addition, there is an effect that the energy can be saved because the excavator does not needlessly operate.

Hereinafter, embodiments of a hydraulic apparatus for an excavator according to the present invention will be described in detail with reference to the accompanying drawings.

6 is a hydraulic circuit diagram of a hydraulic device for an excavator according to the present invention.

The hydraulic device for an excavator according to an example of the present invention shown in Fig. 6 includes two hydraulic pumps 20 and 21; A joystick (100) for generating an operation signal for operating the arm cylinder (33), the boom cylinder, the bucket cylinder and the swing motor (48); And the hydraulic oil discharged from the two hydraulic pumps 20 and 21 is supplied to the arm cylinder 33, the boom cylinder, the bucket cylinder and the swing motor 48 in response to the operation signal generated by the joystick 100 A connecting line 13 for connecting the crowd pilot line 11 for operating the arm cylinder 33 and the crowd pilot line 12 for operating the bucket cylinder; A first pressure sensor (15) installed at the connection line (13) for sensing at least one of the pilot pressure for operating the arm cylinder and the pilot pressure for operating the bucket cylinder; Two second pressure sensors 22 installed on hydraulic lines 31 and 32 of hydraulic oil discharged from the two hydraulic pumps 20 and 21 for sensing the pressure of hydraulic oil discharged from the hydraulic pumps 20 and 21, , 23); A displacement sensor 34 for sensing the extension length of the arm cylinder 33; A shut-off valve (47) installed on the left and right pilot lines (45, 46) for operating the swing motor and capable of opening and closing the left and right pilot lines (45, 46) for operating the swing motor; And a control unit (40) for controlling the shutoff valve (47) in response to signals provided from the first pressure sensor (15), the second pressure sensor (22, 23) and the displacement sensor (34) .

As an example of a circuit diagram of the joystick for operating the boom, the arm, the bucket, and the swing motor, the circuit diagram shown in Fig. 3 can be referred to.

On the other hand, in Fig. 6, the flow path relating to the operation of the boom cylinder and the operation of the bucket cylinder is not shown for simplification of the drawings.

8 shows a hydraulic system in which a shuttle valve 14 is additionally provided as another example of the present invention. According to the figure, a shuttle valve 14 is provided on the connection line 13. [ At this time, the first pressure sensor 15 is connected to the shuttle valve 14 to sense the pilot pressure for operating the arm cylinder and the pilot pressure for operating the bucket cylinder.

According to another example of the present invention, a solenoid valve may be used as the shutoff valve 47.

8, the shuttle valve 14 is installed in the connection line 13 connecting the crowd pilot line 11 for operating the arm cylinder and the crowd pilot line 12 for operating the bucket cylinder, A pressure sensor 15 for sensing the pressure in the valve 14 is mounted so that the pressure sensor 15 senses whether the operating pressure of the arm cylinder and the bucket cylinder is equal to or higher than a preset reference pressure A, .

Meanwhile, pressure sensors 22 and 23 for detecting the pressures from the two hydraulic pumps 20 and 21 are connected to the oil passages 31 and 32 between the hydraulic pumps 20 and 21 and the control valve unit 30, 32 to detect whether the hydraulic oil discharge pressure from the hydraulic pumps 20, 21 is equal to or higher than a predetermined pressure, and generate an output signal corresponding thereto.

A displacement sensor 34 for sensing the extension length of the arm cylinder 33 is provided in the arm cylinder 33 to sense whether the extension / contraction of the arm cylinder is within a predetermined displacement range and output a corresponding signal .

When the pressure of the pilot lines 11 and 12 sensed by the first pressure sensor 15 is equal to or higher than the reference pressure A, the control unit 40 determines that the second pressure sensor 22 When the discharge pressure of the working fluid is equal to or greater than the reference pressure B and when the extension length of the arm cylinder 33 sensed by the displacement sensor 34 is in the reference length range C, To block the left and right pilot lines (45, 46) for swing motor operation.

Here, the reference pressure A in the first pressure sensor 15 is set such that the crowd-side flow path of the arm cylinder 33 or the crowd-side flow path of the bucket cylinder starts to open, 11, and 12, respectively. According to an embodiment of the present invention, the reference pressure A may be set to a pressure at which the valve of the control valve unit (the arm cylinder control valve or the bucket cylinder control valve) is operated by the operation of the joystick lever to completely open the flow path.

In addition, the reference pressure (B) in the second pressure sensor (22, 23) can be applied differently according to the excavation criterion. For example, the pump discharge pressure at the moment when excavation load at excavation starts to be largely generated. According to an example of the present invention, the reference pressure (B) in the second pressure sensor (22, 23) can be set to a pressure value corresponding to 70% of the optimum maximum discharge pressure of the pump. That is, when a pressure of 70% or more of the optimum maximum discharge pressure of the pump is sensed, the second pressure sensors 22 and 23 recognize that the pressure is equal to or higher than the reference pressure B and send the signal to the control unit.

For example, if the pump pressure is 330K, the reference pressure (B) can be set to 300K.

Lastly, the reference length C related to the extension length of the arm cylinder 33 can be arbitrarily set in consideration of the length of the arm cylinder in which a very large excavation force required for excavation can be generated. According to an example of the present invention, the reference length range C of the arm cylinder 33 may be defined as a range corresponding to 40% to 90% of the maximum extension length of the arm cylinder. This will be described with reference to FIG.

For example, as shown in Fig. 7, a distribution diagram of the relationship between the length of the arm cylinder 33 and the axial load of the arm cylinder, the abscissa indicates the axial load of the arm cylinder, and the ordinate indicates the position of the arm cylinder. Here, red indicates that the frequency is high.

7, when the excavator shows a very large excavating force, it can be seen that the length of the arm cylinder is in the range d-d '.

According to the embodiment of the present invention shown in FIG. 7, when the maximum extension length of the arm cylinder is 1750 mm, when the length of the arm cylinder is in the range of 750 mm to 1450 mm, it is understood that the range is very large. Therefore, this section can be defined as a reference length C related to the extension length of the arm cylinder 33. [

According to an example of the present invention illustrated in Figs. 6 and 8, a solenoid valve 47 is provided as a shutoff valve for opening / closing the flow path, respectively, in each of the left pilot line 45 and the right pilot line 46 of the swing motor. Normally, the flow path of the shutoff valve 47 is open, and when the shutoff signal is received from the control unit, the pilot lines 45 and 46 are shut off, and as a result, the swing motor 48 is stopped.

The control unit 40 controls the pressure of the hydraulic fluid detected by the second pressure sensors 22 and 23 when the pressure of the pilot lines 11 and 12 sensed by the first pressure sensor 15 is equal to or higher than the reference pressure A, Only when the pressure is equal to or greater than the reference pressure B and when the extension length of the arm cylinder 33 sensed by the displacement sensor 34 is within the reference length range C, It is possible to output a separate signal D for interrupting the signals 45 and 46. When the additional signal D is applied, the solenoid valve 47 is operated to shut off the flow path.

In this case, the turning of the swinging body by the swing motor is limited, so that even if the joystick is operated in an unintended direction by the driver, the turning of the swinging body does not occur and the side Direction load is removed and only the excavating force is applied.

The hydraulic device for an excavator according to the present invention prevents the rotation of the rotating body even when the joystick is operated in an unintended direction by the driver of the excavator, thereby preventing the lateral force acting on the bucket by rotation of the unnecessary rotating body , Increased durability of excavator parts, and improved energy efficiency.

Figure 1 is a schematic perspective view of an excavator cab with a joystick.

Figures 2a and 2b are schematic diagrams showing the operating direction of the joystick.

3 is a circuit diagram related to a joystick which is an operation device of an excavator.

4 is a schematic hydraulic circuit configuration diagram of a hydraulic device of a conventional excavator.

Fig. 5A is a graph showing the relationship between the excavating force Fa acting on the excavator bucket and the force Fb acting on the excavator side by turning the swivel body when the joystick is operated in the diagonal direction in the excavator having the hydraulic device shown in Fig. .

FIG. 5B shows the magnitude of the force and excavating force in the case of the present invention in which the lateral force is applied as in the case of FIG. 5A.

6 is a schematic hydraulic circuit diagram of an excavator hydraulic system according to an embodiment of the present invention.

FIG. 7 is a diagram showing the relationship between the arm cylinder length and the load distribution of the excavator, and shows the range of the arm length when the magnitude of the excavating force is greater than or equal to a predetermined value, from the arm cylinder length and the load distribution relationship of the excavator.

8 is a schematic hydraulic circuit diagram of an excavator hydraulic system according to another embodiment of the present invention.

DESCRIPTION OF THE RELATED ART [0002]

100, L, R: Joystick

11, 12, 45, 46: pilot line

13: connection line

14: Shuttle valve

15: first pressure sensor

20, 21: Hydraulic pump

22, 23: second pressure sensor

30: Control valve part

31, 32: installed in the hydraulic line of the hydraulic oil

33: arm cylinder,

34: displacement sensor

40:

47: Isolation valve

48: Swing motor

Claims (4)

At least one hydraulic pump (20, 21); A joystick (100) for generating an operation signal for operating the arm cylinder (33), the boom cylinder, the bucket cylinder and the swing motor (48); The operating fluid discharged from the at least one hydraulic pump 20 or 21 is supplied to the arm cylinder 33, the boom cylinder, the bucket cylinder, and the swing motor 48 in response to the operation signal generated by the joystick 100 A control valve unit 30 for controlling the operation of the control valve unit 30; A connecting line 13 for connecting the crowd pilot line 11 for operating the arm cylinder 33 and the crowd pilot line 12 for operating the bucket cylinder; A first pressure sensor (15) installed on the connection line (13) for sensing at least one of the pilot pressure for operating the arm cylinder and the pilot pressure for operating the bucket cylinder, And two second pressure sensors (31, 32) respectively installed in hydraulic lines (31, 32) of hydraulic oil discharged from the at least one hydraulic pump (20, 21) and sensing the pressure of hydraulic oil discharged from the hydraulic pumps 22, 23); A displacement sensor 34 for sensing the extension length of the arm cylinder 33; A shut-off valve (47) installed on the left and right pilot lines (45, 46) for operating the swing motor and capable of opening and closing the left and right pilot lines (45, 46) for operating the swing motor; And A control unit for controlling the shutoff valve (47) to shut off when any one of signals provided from the first pressure sensor (15), the second pressure sensor (22, 23) and the displacement sensor (34) (40) which is disposed on the side of the excavator. 2. The apparatus according to claim 1, wherein the connection line (13) is provided with a shuttle valve (14), which is connected to the shuttle valve (14) Wherein the pilot pressure sensor detects the pilot pressure for the excavator. The method according to claim 1, The control unit (40) When the pressure of the pilot lines 11 and 12 sensed by the first pressure sensor 15 is equal to or higher than the reference pressure A, When the discharge pressure of the hydraulic oil sensed by any one of the two second pressure sensors (22, 23) is equal to or higher than the reference pressure (B) When the extension length of the arm cylinder 33 sensed by the displacement sensor 34 is within the reference length range C, And the left and right pilot lines (45, 46) for operating the swing motor are shut off by controlling the shutoff valve (47). The method of claim 3, The reference pressure A in the first pressure sensor 15 is applied to the pilot lines 11 and 12 at the time when the crowd-side flow path of the arm cylinder 33 or the crowd- Lt; / RTI > The reference pressure (B) in the second pressure sensor (22, 23) is a pressure value corresponding to 70% or more of the optimum maximum discharge pressure of the pump, , And the reference length range (C) of the arm cylinder (33) is in a range corresponding to 40% to 90% of the maximum extension length of the arm cylinder.

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