JP2695336B2 - Hydraulic actuator control device for earth moving machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic actuator control device for an earth-moving machine such as a backhoe, and more particularly, to a hydraulic actuator for driving a working device and an electromagnetic proportional flow control valve of the hydraulic actuator. The present invention relates to a hydraulic actuator control device for an earthmoving machine having flow control means for proportionally controlling the opening degree of an operation lever by supplying a current according to the operation amount of an operation lever.

[0002]

2. Description of the Related Art Conventionally, a hydraulic actuator control device for an earth moving machine is constructed so that a current corresponding to the operation amount of the operation lever is supplied to the electromagnetic proportional flow control valve over the entire operation range of the operation lever. Was.

[0003]

In the above-mentioned control device, the operation of the spool of the hydraulic control valve for controlling the hydraulic actuator is disadvantageously heavy and difficult to operate. In order to make the operation easier, the operation amount of the operation lever is converted into an electric signal, and the hydraulic actuator is operated using an electromagnetic proportional flow control valve that is proportionally controlled to the opening corresponding to the supply current. It is composed. However, in the above-described conventional structure, the electromagnetic proportional flow control valve is configured to drive and control the electromagnetic proportional flow control valve by supplying a current according to the operation amount over the entire operation region of the operation lever. In the middle, the current amount corresponding to the operation position, that is, the valve opening corresponding to the operation position is set, and a desired working speed can be obtained, but for example, the working device is suddenly stopped from a state of operating at high speed. In this case, even if the operating lever is quickly moved from the high-speed operation range to the neutral position, the working device may over-activate due to the inertial force, or the spool of the electromagnetic proportional flow control valve may move in response to a change in current. The work equipment may not operate according to the operation of the operation lever due to a response delay due to catching up, and may exceed a desired stop position or stop just before the stop position. There is a disadvantage to be working. In particular, when driving a heavy-weight working device, the above-mentioned problem has been remarkable. An object of the present invention is to eliminate the above disadvantages.

[0004]

According to a characteristic configuration of the present invention, in the hydraulic actuator control device for an earthmoving machine described at the beginning, when the operation lever is switched from a drive operation position to a neutral position, the operation lever is operated. When an operation speed detecting means for detecting an operation speed of the operation lever in a predetermined area on the high-speed operation side of the operation area is provided, and it is detected that the detection result of the operation speed detecting means is a predetermined value or more. Only, the current supply to the electromagnetic proportional flow control valve is started according to the characteristic of reducing the target current with the passage of time, and a current smaller than the target current is supplied during this supply for a predetermined short time. The point is that a current control means for supplying the control valve is provided.

[0005]

When the working device is operated at a relatively high speed and suddenly stopped at a predetermined position, the hydraulic pressure to the hydraulic actuator is controlled by quickly switching the operating lever from the drive operating position to the neutral position. The current is started to be supplied to the electromagnetic proportional flow control valve according to the target current, and a current smaller than the target current is supplied during this supply for a predetermined time. As a result of operating in the direction in which it is further throttled for a short time while operating in the direction to be throttled, it acts as a brake for a work device that is about to overact due to inertial force of heavy weight, and the current value of the small current By appropriately setting the supply time and the supply time, it is possible to obtain the stop operation that substantially matches the operation feeling of the operation lever.

[0006]

Therefore, by constructing the hydraulic control valve so as to be electrically controlled, the lever operation can be performed lightly and easily, but the working device operating at high speed is suddenly stopped. However, it has become possible to provide a vehicle with excellent maneuverability by suppressing a delay in control response and excessive operation due to inertial force.

[0007]

Embodiments will be described below with reference to the drawings. FIG.
Fig. 2 shows a backhoe as an example of an earth moving machine. The backhoe includes a traveling machine base 2 having a crawler traveling device 1.
The swivel 3 is mounted so as to be freely swivelable around the longitudinal axis by driving a hydraulic motor M for swivel, and a backhoe device 4 [an example of a working device] is connected to the swivel 3. 5 is provided. The backhoe device 4 pivotally connects an arm 7 and a bucket 8 to a boom 6 pivotally supported on a swivel 3 so as to be vertically swingable about a horizontal axis, and respectively connects a boom cylinder C1 and an arm cylinder C to each other.
2. It is configured so that the excavation work can be performed by swinging the drive by the bucket cylinder C3. Also, the boom 6 has a base end 6.
a, an intermediate portion 6b and a distal end portion 6c, each of which is pivotally connected around a vertical axis, and the base end portion 6a and the distal end portion 6c are pivotally connected via a link 9 parallel to the intermediate portion 6b. The bucket 8 is configured to be able to move in the left-right direction while maintaining the parallel posture by swinging and driving the intermediate portion 6b by the offset cylinder C4, and the bucket 8 is offset laterally with respect to the boom base end 6a. By being stored on the swivel table 3, the swing operation can be performed with the maximum swing diameter reduced.

The boom cylinder C1, the arm cylinder C2, and the bucket cylinder C as hydraulic actuators
Each of the turning hydraulic motor 3 and the turning hydraulic motor M is configured to be controlled and operated by a pair of left and right operation levers 11 arranged on a control unit 10 provided on the turning table 3 and capable of performing a cross swing operation. More specifically, as shown in FIG.
1, C2, C3 and the swing motor M are each configured to control the hydraulic flow rate by an electromagnetic proportional flow control valve V, and the operation amount of each operation lever 11 in each operation direction is detected by four potentiometers PM. The control device 12 controls the amount of current supplied to each of the electromagnetic proportional flow control valves V based on the detected operation amount. The offset cylinder C4 is configured to supply a flow rate set in advance by operating the operation switch SW. The control device 12 supplies a current according to the operation amount of the operation lever 11 to proportionally control the opening of the electromagnetic proportional flow control valve V, and a neutral position from the drive operation position of the operation lever 11. During the switching operation to the position, the electromagnetic proportional flow rate control is performed only when it is detected that the operation speed of the operation lever 11 in the predetermined area on the high speed side of the operation area of the operation lever 11 is the predetermined value or more. The supply of a current to the valve V is started according to the characteristic of reducing the target current with the passage of time, and a current smaller than the target current is supplied to the electromagnetic proportional flow control valve V for a predetermined short time during the supply. And a current control means B in a control program format. That is, the controller 12
Executes the control as follows.

The drive control of the boom cylinder C1 as an example of the hydraulic actuator will be described below. FIG.
As shown in, the output X1 of the boom drive potentiometer PM [an example of operation speed detection means] for detecting the lever operation amount by the operation lever 11 is read, and the lever operation speed X2 is calculated from the change of this output [Step 1,
2]. When the lever operation position X1 is at a position higher than the predetermined value a and the deceleration operation is performed at a speed equal to or higher than the predetermined speed b [steps 3, 4, 5], the calculated operation speed X2 is calculated. The magnitude of the minute current I and the supply time are determined based on more predetermined map data [step 6]. Then, the current supply is started to the electromagnetic proportional flow control valve V in accordance with the characteristic that the target current is reduced with the passage of time, and at the same time when the current condition is determined in step 6, the electromagnetic proportional flow control valve V is set to the electromagnetic proportional flow control valve V. The minute current I determined as described above is supplied for a predetermined time [steps 7, 8, 9]. Also, the above steps 3, 4, 5
When the lever is operated slowly and the condition is not met, the control target current Ir of the control characteristic that is predetermined to determine the opening degree in a substantially proportional state corresponding to the operation amount of the operation lever 11 is electromagnetically determined. Supply to the proportional flow control valve V [step 10]. Then, the above-described control is repeated every predetermined time until it is reset [Step 1
1]. As shown in FIG. 3, the minute current I is set to a value much smaller than the magnitude of the control target current Ir [shown by a dotted line in the drawing]. The step 10 constitutes the flow rate control means A, and the steps 6 to 9 constitute the current control means B. The control as described above may be used not only for controlling the boom but also for controlling other hydraulic actuators.

[Other Embodiments] The magnitude of the minute current I and the supply time thereof are constant values set in advance and only for a constant time, instead of being changed according to the operation position of the operation lever 11 as described above. It may be configured to supply to the electromagnetic proportional flow rate control valve V.

[0011] In the claims, reference numerals are provided to facilitate comparison with the drawings, but the present invention is not limited to the configuration shown in the attached drawings.

[Brief description of the drawings]

FIG. 1 is a control block diagram.

FIG. 2 is a control flowchart.

FIG. 3 is a control characteristic diagram

FIG. 4 is a side view of the backhoe.

[Explanation of symbols]

 4 Working Device 11 Operation Lever A Flow Control Means B Current Control Means PM Operation Speed Detection Means V Electromagnetic Proportional Flow Control Valve

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yutarou Morishita 64 Ishizukita-machi, Sakai City, Osaka Prefecture Kubota Sakai Plant (56) Reference JP-A-3-176517 (JP, A)

Claims (1)

(57) [Claims] 1. A working device (4) is configured to be driven by a hydraulic actuator, and an opening of an electromagnetic proportional flow rate control valve (V) of the hydraulic actuator is set according to an operation amount of an operating lever (11). A hydraulic actuator control device in an earthmoving machine equipped with a flow rate control means (A) for supplying an electric current and performing proportional control, wherein during a switching operation from a drive operation position of the operation lever (11) to a neutral position, An operation speed detecting means (PM) for detecting an operation speed of the operation lever (11) in a predetermined area on the high speed operation side in an operation area of the operation lever (11) is provided. only when detecting that the detection result of) is a predetermined value or more, the electromagnetic
Type current flow control valve (V)
When the current supply starts according to the characteristics that reduce both
A hydraulic actuator control device for an earthmoving machine, which is provided with a current control means (B) for supplying a current smaller than a target current to the electromagnetic proportional flow rate control valve (V) for a predetermined short time during the supply.