JP2695335B2 - 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, a current corresponding to the operation amount is supplied to drive and control the electromagnetic proportional flow control valve over the entire operation region of the operation lever. On the way, the current amount corresponding to the operating position, that is, the valve opening corresponding to the current amount is set, and the desired working speed can be obtained, but the working device is stopped, that is, the operating lever is in the neutral position. When the operation is started from the state, the start response of the spool of the electromagnetic proportional flow control valve is slow and the start timing is deviated. Differences may occur. As a result, a difference occurs between the operator's operation feeling of the operation lever and the actual operation state of the work device, and there is a disadvantage that the steering operability is reduced. It is an object of the present invention to solve the above-mentioned problems and prevent a start-up delay when the operating state is changed from the stopped state.

[0004]

In the hydraulic actuator control device for an earthmoving machine described at the beginning, the characteristic configuration of the first invention is interlocked with the operation of the operation lever when starting the drive operation from the neutral position. The supply of the current having the increasing characteristic to the electromagnetic proportional flow control valve is started, and this current is reduced to a value larger than the target current which is constantly supplied corresponding to the operation amount of the operation lever by a predetermined short time. It is provided with a current control means for increasing the time and then decreasing it to the target current. According to a characteristic configuration of the second aspect of the present invention, an operating speed detecting means for detecting an operating speed of the operating lever is provided, and the supply current value increases as the detecting speed increases based on the detection result of the operating speed detecting means. Therefore, the current value changing means for changing the current value of the large current supplied by the current control means is provided. The characteristic configuration of the third aspect of the invention is provided with a pressure sensor for detecting the operating hydraulic pressure of the hydraulic actuator, and the large current supply operation is performed by the current control means until the pressure detected by the pressure sensor reaches a predetermined value. There is a point. According to a fourth aspect of the present invention, there is provided operation speed detection means for detecting an operation speed of the operation lever in a predetermined area on the low speed operation side in an operation area of the operation lever, and the operation speed detection means detects the operation speed. Only when it is detected that the result is equal to or more than a predetermined value, a current control means for supplying a current larger than the target current corresponding to the operation amount of the operation lever to the electromagnetic proportional flow control valve for a predetermined short time is provided. There is a point.

[0005]

According to the characteristic construction of the first aspect of the invention, when the operating lever is operated from the neutral position to the drive operation range in order to operate the working device, the operation lever is operated with respect to the electromagnetic proportional flow control valve in the drive stopped state. A current larger than the target current that is constantly supplied corresponding to the position is supplied for a short time and then drops to the target current.For example, the startup response of the spool of the electromagnetic proportional flow control valve is slow. Even
Supplying a large current will force the spool to operate strongly to accelerate the start timing, and the subsequent movement can be controlled smoothly, the rising characteristics of the hydraulic control flow rate will change rapidly, and the operation response will be quick. become. According to the characteristic configuration of the second invention, when the operation lever is quickly operated, the response delay of the control valve becomes large. Therefore, in such a case, by increasing the value of the large current supplied, The tracking performance of the control valve can be improved, and conversely, when the operation lever is operated slowly, the large current value is set to a small value as described above. Therefore, there is no risk that the control valve will be driven, and it is possible to prevent a sudden operation that does not meet the driver's intention. According to the characteristic configuration of the third aspect of the invention, the operating oil pressure of the hydraulic actuator that is the drive control target is directly detected, and the large current described above is supplied until the detected oil pressure reaches a predetermined value. Appropriate startup control can be realized while monitoring the operating status, and the inconvenience of unnecessary overdriving can be avoided.
According to the characteristic configuration of the fourth invention, when the operation lever is operated in the high speed operation region,
Since the large current supply as described above is not performed, shock does not occur due to excessive current when the work device is operating at high speed, and even when it is operated slowly even at low speed side In this case, since the large current supply as described above is not performed and the excessive pressure oil is not supplied to the hydraulic actuator, it is possible to prevent the drive shock from occurring.

[0006]

Therefore, while having the advantage that the lever operation can be performed lightly by using the electrically controlled hydraulic control valve, the response delay when starting the hydraulic actuator from the drive stopped state and the response delay for quick operation of the operating lever are provided. It was possible to improve the maneuverability by effectively blocking the operation by making the operating feeling of the operating lever and the operating condition of the work device coincide with each other as much as possible. Moreover, it has been possible to effectively prevent a drive shock from being generated by supplying a large current more than necessary, and to provide a vehicle with excellent driving safety.

[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 drive device for driving the operation lever 11 from a neutral position. At the start of the operation, the operation lever 11
Current control means B for supplying a one-shot current, which is larger than the target current in the flow rate control means A corresponding to the operation amount of the above, to the electromagnetic proportional flow rate control valve V for a predetermined short time.
Based on the operating speed of the operating lever 11, the current value of the one-shot current by the current control means B is changed so that the higher the detection speed is, the larger the current value supplied to the electromagnetic proportional flow rate control valve V is. The current value changing means C is provided in the form of a control program. That is, the controller 12
The control is executed as follows.

The control of the boom cylinder C1 will be described below as an example of the hydraulic actuator. As shown in FIG. 2, the output X1 of the potentiometer PM [an example of speed detecting means] corresponding to the drive operation of the boom cylinder C1 is read [step 1], and the operation lever 11 is operated from the neutral position to the drive operation range. [Steps 2 and 3], a one-shot current having a large current value close to the maximum supply value is supplied to the boom electromagnetic proportional flow control valve V for a predetermined time determined in advance [Step 4]. If the operation lever is not in the neutral position in step 2, the output of the pressure sensor 13 provided in the pressure oil supply path for the boom is read [step 5], and the lever 11 is operated from the periodic output change of the potentiometer PM. Speed X2
Is calculated [step 6]. The operation position of the operation lever 11 is in the predetermined area Z on the low speed drive side, and
When the calculated operation speed X2 becomes larger than the predetermined value a [steps 7 and 8], the map data determined in advance is obtained from the data of the detected value X1 of the operation position of the operation lever 11 and the operation speed X2 at that time. Based on this, the magnitude of the one-shot current, which is larger than the control target current that is constantly supplied, is calculated with a predetermined characteristic in a substantially proportional state corresponding to the lever operation amount, and at the same time, the one-shot current is set to the boom electromagnetic field. Supply to the proportional flow control valve V [steps 9 and 10]. Further, the output P of the pressure sensor 13 is a predetermined value P1.
Then, the supply of the one-shot current is stopped, and a control target current having a predetermined characteristic that is substantially proportional to the lever operation amount is supplied to the boom electromagnetic proportional flow control valve V [step 11-13]. If the operation position of the operation lever 11 is on the high speed drive side in step 7, or if the operation speed X2 calculated in step 8 is smaller than the predetermined value a, step 13
Then, the control target current having a predetermined characteristic in a substantially proportional state corresponding to the lever operation amount is supplied to the boom electromagnetic proportional flow rate control valve V. Then, the above operation is repeated until it is reset [step 14]. The step 13 constitutes the flow rate control means A, the steps 4 and 10 constitute the current control means B, and the step 9 constitutes the current value changing means C. By adding the one-shot current as described above, the electromagnetic proportional flow control valve V
In contrast, the control current is supplied in such a manner that the control current is supplied with a characteristic that the rise is rapid and the value of the target current is increased to a value larger than the target current that is constantly supplied corresponding to the operation position of the operation lever 11, and then is decreased to the target current. As shown in FIG. 3, when the operation is started from the stopped state, the smooth flow rate control that almost corresponds to the lever operation can be performed as compared with the conventional characteristic shown by the dotted line, and the operation lever can be quickly operated during the operation. However, for the same reason, as shown in FIG. 4, smooth flow rate control becomes possible.

The current control as described above may be used not only for controlling the boom but also for controlling other hydraulic actuators.

[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] Control characteristic diagram at startup

[Fig. 4] Control characteristic diagram during operation

FIG. 5 is an overall side view of the backhoe.

[Explanation of symbols]

 4 Working device 11 Operation lever 13 Pressure sensor A Flow rate control means B Current control means C Current value changing means PM Operation speed detection means V Electromagnetic proportional flow rate control valve

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

Claims (4)

(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 when starting a driving operation from a neutral position of the operating lever (11) ,
Increased with respect to the electromagnetic proportional flow control valve (V) in conjunction with operation
When the supply of additive current is started, this current is
It is constantly supplied according to the operation amount of the work lever (11).
For a specified short time to a value greater than the target current
A hydraulic actuator control device for an earthmoving machine, comprising a current control means (B) for decreasing the current to a target current . 2. An operating speed detecting means (PM1) for detecting an operating speed of the operating lever (11) is provided, and the higher the detected speed is, the higher the detected speed is based on the detection result of the operating speed detecting means (PM1). The hydraulic actuator control device for an earthmoving machine according to claim 1, further comprising current value changing means (C) for changing the current value of the large current supplied by the current control means (B) so as to increase the supplied current value. 3. A pressure sensor (13) for detecting an operating oil pressure of the hydraulic actuator, the pressure sensor (1) being provided.
The hydraulic actuator control device for an earthmoving machine according to claim 1 or 2, wherein the current control means (B) performs a large current supply operation until the pressure detected by 3) reaches a predetermined value. 4. An operation speed detecting means (PM1) for detecting an operation speed of the operation lever (11) in a predetermined area on the low speed operation side of an operation area of the operation lever (11) is provided. Only when it is detected that the detection result of the speed detecting means (PM1) is equal to or more than a predetermined value,
A current control means (B) for supplying a current larger than a target current corresponding to the operation amount of the operation lever (11) to the electromagnetic proportional flow control valve (V) for a predetermined short time. 4. The hydraulic actuator control device for an earthmoving machine according to any one of 3 to 3.