JPH0633617B2 - Hydraulic control equipment for civil engineering construction machinery - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a hydraulic control device provided in a civil engineering construction machine such as a hydraulic shovel and capable of automatically controlling a pressing force of a work machine against an excavation target surface.

[Conventional technology]

In excavation work that is performed by a hydraulic shovel, etc., if the pressing force against the surface to be excavated is too large, the load becomes excessive and relief occurs. If the pressing force is too small, the load will be too small, and the load will be too small, and the amount of soil excavated will be insufficient.

[Problems to be solved by the invention]

Conventionally, control is performed manually by an operator so as not to cause such an excessive load or an excessive load, but when the operator is not an expert, such an excessive load or an excessive load may occur. Is inevitable, and it is difficult to expect improvement in work efficiency.

In addition, as a reference technique, in order to excavate along the surface of a steel sheet pile for earth stop buried in the soil, conventionally, there has been proposed a technique in which a predetermined cylinder is pressurized by an accumulator. However, this is not intended for normal excavation, and unless the accumulator is made particularly large, the pressing force changes significantly due to the displacement of the cylinder, and once the accumulator is used, the next work is performed. This conventional technique is difficult to apply for ordinary excavation because a means for accumulating the accumulator until a predetermined pressure is required by the cycle is required and the device becomes large in size.

Further, as another reference technique, it has been conventionally proposed to directly detect a load by a force sensor in a robot or the like to control the pressing force. However, it is difficult to perform smooth excavation work by feeding back the load as in this conventional technology for civil engineering construction machines where load fluctuations are extremely severe, and generally force sensors are used for price, durability, and structure. There is a problem in using it for the civil engineering construction machine to which the present invention is applied in terms of the mounting method, etc., and eventually, it is difficult to apply this conventional technique.

The present invention has been made in view of the above circumstances in the prior art, and an object thereof is to provide a hydraulic control device for a civil engineering and construction machine that can automatically control the pressing force against an excavation target surface of a working machine to an optimum value. To do.

[Means for solving problems]

In order to achieve this object, the present invention has a link mechanism including at least two members that can rotate with respect to each other, such as a boom and an arm, and a working machine such as a bucket connected to the link mechanism. Swivel, a first hydraulic actuator such as a boom cylinder and an arm cylinder that rotates a link mechanism, a second hydraulic actuator such as a bucket cylinder that drives a working machine, and a swivel structure. In a hydraulic control device for a civil construction machine such as a hydraulic shovel that includes a third hydraulic actuator such as a swing motor that rotates about an axis, for example, a first hydraulic actuator such as a boom cylinder or an arm cylinder, a bucket cylinder, or the like. Second hydraulic actuator,
An operation command means for outputting an operation command signal for driving a third hydraulic actuator such as a swing motor, and a first predetermined actuator for giving a pressing force to a surface to be excavated among the first, second and third hydraulic actuators. , A pressure control means including a pump regu- lator for controlling the drive pressure of the boom cylinder to a predetermined pressure, a direction switching valve, etc., and a second predetermined actuator different from the above-mentioned first predetermined actuator, for example, an arm cylinder. A control device for obtaining an operation command signal based on a predetermined functional relationship according to the corresponding operation command signal and outputting the operation command signal to the pressure control means is provided.

[Work]

The present invention is configured as described above, whereby the second
In response to an operation command signal corresponding to a predetermined actuator such as an arm cylinder, an operation command signal is output from the control device to the pressure control means, whereby a first predetermined actuator for applying a pressing force to the excavation target surface, for example, a boom cylinder. The driving pressure is controlled to be a predetermined pressure, and the pressing force against the excavation target surface of the work machine, for example, the bucket can be automatically controlled to an optimum value.

〔Example〕

Hereinafter, a hydraulic control device for a civil engineering construction machine according to the present invention will be described with reference to the drawings. FIG. 1 is a circuit diagram showing a configuration of a main part of a first embodiment of the present invention, and FIG. 2 is an excavation of a hydraulic shovel, which is an example of a civil construction machine equipped with the first embodiment shown in FIG. FIG. 3 is a side view showing a state at the time of work, and FIG. 3 is a block diagram showing a configuration of a main part included in the control device provided in the first embodiment shown in FIG. 1 and a connection relationship between the control device and related devices. .

In these drawings, particularly in FIG. 2, 1 is a revolving structure which constitutes the main body of the hydraulic shovel, 2 is a boom rotatably connected to the revolving structure 1, and 3 is rotatably connected to the boom 2. The arm 4 is a bucket rotatably connected to the arm 3. The boom 2 and the arm 3 described above constitute a link mechanism, the bucket 4 constitutes a working machine, and the link mechanism and the working machine constitute a connecting body 6 which is rotatable about a pivot shaft 5. There is. Reference numeral 52 is a boom cylinder for rotating the boom 2, 58 is an arm cylinder for rotating the arm 3, and these actuators constitute a first hydraulic actuator for rotating the above-mentioned link mechanism. Reference numeral 54 denotes a bucket cylinder, which is a second hydraulic actuator for rotating the bucket 4, that is, the working machine. Although not shown, such a hydraulic shovel is provided with a revolving motor for revolving the revolving structure 1, and this constitutes a third actuator for rotating the above-mentioned connecting body 6. The swing body 1, the link mechanism including the boom 2 and the arm 3, and the connecting body 6 and the boom cylinder 5 configured by the working machine or the like including the bucket 4.
2, a first hydraulic actuator composed of an arm cylinder 58, a second hydraulic actuator composed of a bucket cylinder 54, and a third actuator composed of a swing motor are commonly used in a civil construction machine such as a hydraulic shovel illustrated in FIG. It is provided.

Further, 252 is an angle detector that detects the relative angle between the revolving unit 1 and the boom 2, 258 is an angle detector that detects the relative angle between the boom 2 and the arm 3, and 254 is a relative angle between the arm 3 and the bucket 4. These are angle detectors for detecting the movement of the second predetermined actuator, which will be described later, for example, an operation displacement detecting means for detecting an operation displacement of the arm cylinder 58. Output a signal.

In FIG. 2, H is the ground on which the hydraulic shovel is arranged, D is the surface to be excavated by the bucket 4, and K is the surface to be excavated.
Indicates a surface formed by excavation.

Next, the construction of the essential parts of the first embodiment provided in such a hydraulic shovel will be described with reference to FIGS.

In FIG. 1, 52, 58 and 54 are the boom cylinder, arm cylinder, bucket cylinder, and
252, 258 and 254 are the angle detectors described above. 14 is a swing motor 56 and an arm cylinder 5
Reference numeral 8 is a first variable displacement hydraulic pump that supplies pressure oil to 8, and 16 is a second variable displacement hydraulic pump that supplies pressure oil to the boom cylinder 52 and the bucket cylinder 54. Reference numeral 26 denotes a turning direction switching valve for controlling the flow direction of pressure oil supplied from the first variable displacement hydraulic pump 14 to the turning motor 56.
Reference numeral 8 denotes an arm direction switching valve for controlling the flow direction of the pressure oil supplied from the hydraulic pump 14 to the arm cylinder 58, and 22
Is from the second variable displacement hydraulic pump 16 to the boom cylinder 5
2, a boom direction switching valve for controlling the flow direction of the pressure oil supplied to the hydraulic pump 16, and 24 for the bucket cylinder 5 from the hydraulic pump 16.
4 is a bucket directional control valve for controlling the flow direction of the pressure oil supplied to No. 4. 15 and 17 are hydraulic pumps 1 respectively
A pump regulator for controlling the displacement of the pumps 4, 16 of which the pump regulator 17 controls the drive pressure of a first predetermined actuator, for example, the boom cylinder 52, that applies a pressing force to the excavation target surface to a predetermined pressure. It constitutes a pressure control means. 264 and 266 are pressure detectors that detect the pressure of the pressure oil discharged from the hydraulic pumps 14 and 16 and output it as signals. 212,
214, 216 and 218 are boom cylinders 5, respectively.
2, a boom cylinder 2, a bucket 4, a revolving structure 1, which are provided corresponding to the bucket cylinder 54, the revolving motor 56, and the arm cylinder 58, and are driven by these actuators.
The operation command means outputs an operation command signal for operating the arm 3. Reference numeral 230 is a target pressure setting means for outputting an optimum target pressure setting signal according to the working conditions such as the surface to be excavated.

Further, 200 is a control device, which is operation command means 212, 21.
4, 216, 218 output operation command signals, angle detectors 252, 258, 254 output angle signals, target pressure setting means 230 output target pressure signals, and pressure detectors 264, 266 output. The pressure signal to be input is input and predetermined arithmetic processing is performed to perform the predetermined calculation processing, and the pump regu-lators 15 and 17, the boom direction switching valve 22, the bucket direction switching valve 24, the turning direction switching valve 26, and the arm direction switching. An operation command signal is output to the valve 28. The control device 200 determines the operation command signal corresponding to the second predetermined actuator, for example, the arm cylinder 58, and the pressure of the pressure oil supplied to the first predetermined actuator, for example, the boom cylinder 52, which gives the pressing force to the excavation target surface. Function table 2 for setting the functional relationship with the target pressure signal
01, a function table 202 in which a functional relationship between a link angle signal obtained by performing a predetermined calculation according to the angle signals output from the angle detectors 252, 258, 254 and a correction value is set, and a function a multiplier 203 for outputting a desired pressure signal by multiplying the correction value outputted from the function table 202 signal P _r output from the table 201, is output as the signal P _r from the pressure detector 266 of the above An adder 20 that adds the pressure signal P _s and outputs a signal ΔP
4 and a function table 2 in which the functional relationship between this signal ΔP and the differential signal related to the pump regulator 17 is set.
05 and the differential signal output from the function table 205 to integrate the operation command signal X into the pump regulator 1
7 and an integrator 208 for outputting to the No.

In the above-mentioned function table 201, the target pressure signal is O until the operation command signal reaches the predetermined value, and the target pressure signal has a constant value when the operation command signal exceeds the predetermined value. In addition, a relationship is set in which the constant value changes according to the target pressure setting signal output from the target pressure setting means 230. That is, the function table 201 constitutes first correction means for correcting the functional relationship between the predetermined operation command signal and the target pressure signal according to the target pressure setting signal.

In the function table 202 described above, the correction value gradually decreases toward K until the link angle signal reaches the predetermined value, the correction value becomes K when the link angle signal reaches the predetermined value, and the correction value becomes larger than the predetermined value when the link angle signal reaches the predetermined value. The functional relation is set so that becomes even smaller. That is, this function table 202
And the above-mentioned multiplier 203 includes angle detectors 252, 258,
A second correction unit that corrects the functional relationship between the predetermined operation command signal and the target pressure signal in the function table 201 according to the angle signal (displacement signal) output from 254 is configured.

The operation in the embodiment thus configured is as follows.

In the state shown in FIG. 2, in the case of normal excavation in which the surface to be excavated is relatively soft, when the arm cylinder 58 is extended to perform excavation, the pressure on the head side of the boom cylinder 52 becomes the pressure that gives the pressing force. As described above, the boom cylinder 52 serves as the first predetermined actuator and the arm cylinder 58 serves as the second predetermined actuator.

At this time, from the target pressure setting means 230 to the boom cylinder 5
The target pressure setting signal is output to the control device 200 so that the pressure on the head side of 2 becomes the optimum pressure, and the operation command signal for driving the arm 3 is output from the operation command means 218 to operate the operation command means 212. An operation command signal for driving the boom 2 is output from the control device 20 in response to this.
0 is an arm directional control valve 28, a boom directional control valve 22
An operation command signal for switching each of the above is output. As a result, the pressure oil discharged from the first variable displacement hydraulic pump 14 is supplied to the arm cylinder 58 via the direction switching valve 28, the arm cylinder 58 extends, and the arm 3 moves to the second position.
The pressure oil that rotates in the clockwise direction in the figure and that is discharged from the second variable displacement hydraulic pump 16 is appropriately supplied to the head side of the boom cylinder 52 via the direction switching valve 22. With this, excavation work is performed. During this excavation work, the pressure detector 266 supplies the pressure P _s of the pressure oil of the second variable displacement hydraulic pump 16 supplied to the head side of the boom cylinder 52.
Is detected and output to the control device 200, and the angle detector 2
52, 258 and 254 output an angle signal to the control device 200 in accordance with the displacement of the arm 3, that is, the change of the working posture.

In the control device 200, the function table 20 is generated according to the operation command signal for driving the arm 3 and the target pressure setting signal.
1, the target pressure signal for driving the boom cylinder 52 is output, and the correction value is output from the function table 202 according to the link angle signal obtained by calculating the angle signal.
The multiplier 203 multiplies the target pressure signal by the correction value to output a signal P _r , and this signal P _r and the pressure signal P _s output from the pressure detector 266 are added by an adder 204 to output a signal ΔP. Then, a differential signal is output from the function table 205 according to the signal ΔP, the differential signal is integrated by the integrator 208, and the operation command signal X is output to the pump regulator 17. The pump regulator 17 appropriately operates in response to the operation command signal X, whereby the tilt angle of the second variable displacement hydraulic pump 16 is controlled, and the second variable displacement hydraulic pump 16 is discharged. The pressure of the pressure oil that is supplied, that is, the pressure of the pressure oil that is supplied to the boom cylinder 52 is controlled to a predetermined pressure.

In the first embodiment configured in this way, the arm 3
During the excavation work performed by operating the, the pressure on the head side of the boom cylinder 52 can be automatically determined to an optimum pressure set in advance, that is, an excessive load without affecting the skill of the operator, Without underestimation,
The excavation work efficiency can be improved.

In the first embodiment, the pressure control means is constituted by the pump regulator 17 which controls the pressure on the head side of the boom cylinder 52 to a predetermined pressure, and responds to the pressure signal P _s from the pressure detector. However, the present invention is not limited to this, and the pressure control means is a pressure control valve having a variable set pressure provided in the discharge passage of the second variable displacement hydraulic pump 16. You can buy it.

FIG. 4 is a circuit diagram showing a configuration of a main part of a second embodiment of the present invention, and FIG. 5 is a configuration of a main part and a control device included in a control device provided in the second embodiment shown in FIG. FIG. 3 is a block diagram showing a connection relationship between the and related devices.

Shall apply to this second embodiment, as shown in FIG. 4, it is provided with a pressure detector 272 for detecting the pressure of head side of the boom cylinder 52, the pressure signal P _H of the pressure detector 272 It is adapted to be output to the adder 204 of the control device 200. Then, the adder 2 is included in the control device 200.
A signal ΔP output from 04 and the boom directional control valve 22
There is provided a function table 206 in which a functional relationship with the operation command signal X _A for operating the is set. In the function table 206, for example, the operation command signal X _A is O and ΔP is from the first predetermined value to the second predetermined value until ΔP reaches the first predetermined value.
Of up to the predetermined value becomes gradually larger operation command signal X _A, shall apply after the second predetermined value functional relationship actuation command signal X _A is a constant value is set. The boom direction switching valve 22 constitutes pressure control means.

In the second embodiment, the pressure on the head side of the boom cylinder 52 is detected by the pressure detector 272, and the pressure signal P _H of the pressure detector 272 is added to the signal ΔP.
Actuation command signal X _A is output to the boom directional control valve 22, thereby squeezed head side of the directional control valve 22 is suitably, this pressure head side of the boom cylinder 52 is automatically maintained at a predetermined pressure by the relative .

FIG. 6 is a circuit diagram showing the configuration of the main part of the third embodiment of the present invention, and FIG. 7 is the configuration of the main part and the control device included in the control device provided in the third embodiment shown in FIG. FIG. 3 is a block diagram showing a connection relationship between the and related devices.

This third embodiment is suitable when the surface to be excavated is harder than in the case of normal excavation, and as shown in FIG. 6, a pressure detector 273 for detecting the pressure on the rod side of the boom cylinder 52 is used. The pressure signal P _R of the pressure detector 273 is provided and is output to the adder 204 of the control device 200. Then, the control device 200 is provided with the signal ΔP output from the adder 204 and the boom directional control valve 2.
A function table 207 is provided in which a functional relationship with the operation command signal X _B for activating 2 is set. In the function table 207, for example, the operation command signal X _B has a relatively large constant value until ΔP reaches the first predetermined value, and after the predetermined value, the operation command signal X _B has a value larger than the constant value. A functional relationship that takes a gradually smaller value is set. Further, the functional relationship of the function table 201 is set to be different from that in the above-described first and second embodiments as needed. In the third embodiment as well, the boom direction switching valve 22 constitutes pressure control means.

When the surface to be excavated is hard, the boom cylinder 52 is pushed up by the excavation reaction force. In the third embodiment, the pressure on the rod side of the boom cylinder 52 is controlled by the pressure detector 273. This pressure detector 2
Actuation command signal X _B corresponding to the 73 signal ΔP by adding the pressure signal P _R of is output to the drive unit of the boom directional control valve 22, which in throttled rod side of Yotsute boom directional control valve 22 is appropriately The pressure on the rod side of the boom cylinder 52 is automatically maintained at a predetermined pressure.

Although the boom cylinder 52 is used as the first actuator in the above-described embodiment, the swing motor 56 can be used as the first actuator when excavating by applying a pressing force by the swing body 1. By doing so, the present invention can be applied. Further, although the switching valve is a center bypass type in each of the above embodiments, it may be a neutral and pump port block type.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY The hydraulic control device for a civil engineering construction machine of the present invention can automatically control the pressing force against the excavation target surface of the work machine to an optimum value, and thus the excessive load or the excessive load as in the conventional manual operation occurs. Therefore, there is an effect that the working efficiency is improved as compared with the conventional one, and damage to the connecting body and the hydraulic equipment can be prevented.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing the essential configuration of a first embodiment of a hydraulic control device for civil engineering construction machines according to the present invention, and FIG. 2 is a civil engineering construction machine equipped with the first embodiment shown in FIG. FIG. 3 is a side view showing a state during excavation work of the hydraulic shovel given as an example, and FIG. 3 is a main part configuration included in the control device provided in the first embodiment shown in FIG. FIG. 4 is a block diagram showing the connection relationship, FIG. 4 is a circuit diagram showing the essential configuration of the second embodiment of the present invention, and FIG. 5 is included in the control device provided in the second embodiment shown in FIG. FIG. 6 is a block diagram showing the configuration of essential parts and the connection relationship between the control device and related equipment. FIG. 6 is a circuit diagram showing the structure of essential parts of the third embodiment of the present invention. FIG. 7 is shown in FIG. A main part configuration included in the control device provided in the third embodiment and a connection relationship between the control device and related devices will be described. It is to block diagram. 2 ... Boom (link mechanism), 3 ... Arm (link mechanism), 4 ... Bucket (working machine), 5 ... Revolving axis, 6 ...
... Connecting body, 17 ... Pump regulator (pressure control means), 22 ... Boom direction switching valve (pressure control means),
52 ... Boom cylinder (first hydraulic actuator,
1st predetermined actuator), 54 ... bucket cylinder (second hydraulic actuator), 56 ... swing motor (third hydraulic actuator), 58 ... arm cylinder (first hydraulic actuator, second predetermined actuator) Actuator), 200 ... Control device, 201 ... Function table (first correction means), 202 ... Function table (second correction means), 203 ... Multiplier (second correction means), 2
04 ... Adder, 205, 206, 207 ... Function table, 208 ... Integrator, 212, 214, 216, 2
18: operation command means, 230: target pressure setting means,
252, 258, 254 ... Angle detector, 266, 27
2,273 ... Pressure detector.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomohiko Yasuda 650, Kazunachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura Plant (56) References JP-A-56-14605 (JP, A) JP-A-SHO 59-126829 (JP, A)

Claims (6)

[Claims] 1. A link body having a link mechanism composed of at least two members rotatable with respect to each other and a working machine connected to the link mechanism, wherein the link body is rotatable about a swing shaft, and the link mechanism is rotated. A first hydraulic actuator to move,
A hydraulic control device for a civil engineering construction machine, comprising: a second hydraulic actuator that drives the work machine; and a third hydraulic actuator that rotates the connecting body around the swing shaft. An operation command means for outputting an operation command signal for driving the third hydraulic actuator, and a driving pressure of the first predetermined actuator which gives a pressing force to the excavation target surface among the first, second and third hydraulic actuators. In accordance with an operation command signal corresponding to a second pressure actuator different from the first predetermined actuator among the first, second and third hydraulic actuators. Soil which is provided with a control device that obtains an operation command signal based on a defined functional relationship and outputs the operation command signal to the pressure control means. Hydraulic control system for a construction machine. 2. The control device has target pressure setting means for outputting a target pressure setting signal, and the control device has first correcting means for correcting a predetermined functional relationship according to the target pressure setting signal. A hydraulic control device for a civil engineering and construction machine according to claim (1). 3. An operating displacement detecting means for obtaining an operating displacement of a second predetermined actuator and outputting a displacement signal to a control device, and the control device corrects a predetermined functional relationship according to the displacement signal. A hydraulic control device for a civil construction machine according to claim (1) or (2), characterized in that the hydraulic control device has a second correcting means. 4. The hydraulic control device for a civil construction machine according to claim 1 or 2, wherein the pressure control means includes a pump regulator. 5. The civil construction machine according to claim 1 or 2, wherein the pressure control means includes a directional control valve for controlling the drive pressure of the first predetermined actuator. Hydraulic control device. 6. A hydraulic control device for a civil construction machine according to claim 1, wherein the pressure control means includes a pressure control valve with a variable set pressure.