JP2651076B2 - 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 feature of the present invention, there is provided a hydraulic actuator control device for an earthmoving machine described at the beginning, comprising a pressure detecting means for detecting an operating internal pressure of a hydraulic oil supply side of the hydraulic actuator. During the switching operation of the operation lever from the drive operation position to the neutral position, a reverse current is supplied to the electromagnetic proportional flow control valve only while the detection value of the pressure detection means rises to a predetermined value or more. The point is that a reverse current supply means is provided.

[0005]

For example, when the operating lever is returned from the driving state to the neutral position in order to suddenly stop the operating device from operating at a relatively high speed, the operating device is supplied to the electromagnetic proportional flow control valve until that time. Since the reverse current is supplied in the opposite direction to the current direction, the working device attempts to over-activate beyond the desired stop position due to inertial force or response delay, etc. Will supply pressure oil in one direction. As a result, the braking force acts to suppress the excessive operation by the hydraulic pressure in the opposite direction, and the stop operation of the working device can match the operator's lever operation feeling as much as possible. Moreover, after the internal pressure on the hydraulic oil supply side of the hydraulic actuator reaches a predetermined value due to the pressure increase due to the push-back action caused by the hydraulic pressure in the reverse direction, the supply of the reverse current is stopped. It can be prevented from being operated in the opposite direction to the operation direction.

[0006]

Accordingly, the hydraulic control valve is electrically controlled so that the lever operation can be performed lightly and easily, but when the working device that operates at high speed is suddenly stopped, the hydraulic control valve is adapted almost to the feeling of lever operation. What can provide a reliable stop operation can be provided. In addition, by detecting the internal pressure of the hydraulic actuator, it is possible to unnecessarily lengthen the supply of the reverse current, thereby reliably preventing adverse effects such as the working device swinging back in the reverse direction against the operator's will. Thus, the occurrence of a shock due to the stop of the working device can be suppressed.

[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 cylinders C1, C2, C3 and the swing motor M
A pressure sensor S (an example of a pressure detecting means) for detecting an internal working pressure is provided in each of the pressure oil supply paths for the pressure oil. 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. During the switching operation to the position, only when it is detected that the operation speed of the operation lever 11 in a predetermined region on the high-speed operation side of the operation region by the operation lever 11 is equal to or higher than a predetermined value, the operation lever 11
And a reverse current supply means B for supplying a reverse current to the electromagnetic proportional flow control valve V for a predetermined short time from the time when is operated to the neutral position in the form of a control program.
That is, the control device 12 performs control as follows.
Hereinafter, the operation control of the boom cylinder C1 as an example of the hydraulic actuator will be described. As shown in FIG. 2, the boom cylinder C operated by the operation lever 11
The output X1 of the potentiometer PM for one operation (an example of an operation speed detecting means) and the output of the pressure sensor S on the pressure oil supply side of the boom 6 are read (steps 1, 2).
When the output X1 of the potentiometer changes, the operation lever 11
Is calculated (step 3). Then, a lever operation is performed in a direction to decelerate the boom cylinder C1, and the output X1 [lever operation position] of the potentiometer PM is larger than a predetermined value a. Is greater than or equal to the predetermined value b [Steps 4, 5, 6], the current value of the reverse current I is determined by the lever speed X2 based on the predetermined map data [Step 7]. Until the operation lever 11 is operated within the neutral dead zone, the control target current Ir corresponding to the lever operation amount is supplied to the electromagnetic proportional flow control valve V based on predetermined characteristics to proportionally control the opening. [Steps 8 and 9]. When the operating lever 11 enters the neutral dead zone, the reverse current I is supplied to the electromagnetic proportional flow control valve V until the output P of the pressure sensor S increases to a predetermined value P1 from that point. [Steps 10 to 12]. That is, as shown in FIG. 3, by supplying a reverse current, the pressure in the pressure oil passage on the side opposite to the pressure oil supply passage increases, and the internal pressure on the pressure oil supply passage side increases again by the pushing back action. To begin with, the reverse current I is supplied until reaching the predetermined value P1, which has risen slightly in the re-rise. If the conditions are not satisfied in steps 5, 6, and 7, the control target current Ir corresponding to the lever operation amount is supplied to the electromagnetic proportional flow control valve V based on predetermined characteristics to open the valve. Is proportionally controlled [step 13]. The above-described control is repeated every predetermined time until the control is reset (step 14). Steps 8 and 13 constitute flow rate control means A, and steps 10 to 12 constitute reverse current supply means B. The above-described control is not limited to the operation control of the boom 6, and may be used for controlling other hydraulic actuators. The current value of the reverse current may be set unconditionally constant.

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 Operating lever A Flow control means B Reverse current supply means S Pressure detection means V Electromagnetic proportional flow control valve

 ──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Yutaro Morishita 64 Ishizu-Kitacho, Sakai-shi, Osaka Kubota Sakai Works Co., Ltd. (56) References JP-A-3-176517 (JP, A) JP-A-2- 173810 (JP, A)

Claims (1)

(57) [Claims] The working device (4) is configured to be driven by a hydraulic actuator, and an opening of an electromagnetic proportional flow control valve (V) of the hydraulic actuator is adjusted according to an operation amount of an operating lever (11). A hydraulic actuator control device for an earth moving machine provided with a flow control means (A) for supplying a current to perform proportional control, wherein a pressure detection means (S) for detecting an operating internal pressure of a hydraulic oil supply side of the hydraulic actuator is provided. With the operation lever (1
During the switching operation from the driving operation position to the neutral position in 1), the electromagnetic proportional flow control valve (V) is reversed only while the detected value of the pressure detecting means (S) rises to a predetermined value or more. A hydraulic actuator control device for an earth moving machine having a reverse current supply means (B) for supplying a direction current.