JP2821339B2 - Control device of construction machine with attachment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device applied to a construction machine with an attachment, for example, a hydraulic shovel equipped with an attachment hammer.

[0002]

2. Description of the Related Art In a conventional construction machine with an attachment, an operator manually changes the engine speed so as to obtain an appropriate pump flow rate according to the type of the attachment. There are attachments that need to be driven at a constant pump flow rate, such as a hammer in a hydraulic shovel. On the other hand, as disclosed in Japanese Utility Model Laid-Open No. Hei 4-24636, there is an engine speed control device that controls only the engine speed using a signal indicating that an attachment has been operated.

[0003] The control device described in this publication, when the use of the attachment is detected by the detecting means, the target rotational speed set by the setting means according to the type of attachment or the engine speed matching the driving force of the attachment. The variable means for controlling the fuel injection amount is controlled so as to obtain the following.

[0004]

The manual adjustment by the operator is not easy to obtain a proper pump flow rate.
Further, in the control device described in the above-mentioned publication, the pump flow rate changes depending on the load pressure of the attachment due to the constant torque control function of the ordinary pump, and a constant pump flow rate, which is the original purpose, is supplied. Can not do.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a control device for a construction machine with an attachment which can be controlled so that a required pump flow rate can be obtained regardless of a pump load pressure. Things.

[0006]

According to a first aspect of the present invention, a hydraulic pump driven by an engine and oil discharged from the hydraulic pump are directed to a hydraulic actuator in accordance with an operating device operated by an operator. In a construction machine with an attachment having a directional control valve for supplying while switching, a detecting means for detecting that an operator for the attachment has been operated by an operator, and a variable fuel injection amount of the engine to increase the engine speed. Rotation speed variable means for variably adjusting to a target rotation speed, and a hydraulic pump
A flow rate variable means for variably adjusting a pump flow rate discharged from the apparatus to a target flow rate, a target rotation speed storage section and a target flow rate storage section for preliminarily storing a target rotation speed and a target flow rate, respectively. Is entered when
A signal to fix the gin rotation speed to the target rotation speed is variable.
Means and output pump flow to pump load pressure.
Regardless of the pressure range,
Control means for outputting a signal to the flow rate variable means, a target speed changer for switching a plurality of target speeds set in the control means, and a target flow rate switch for switching a plurality of target flow rates set in the control means. It is a control device of a construction machine with an attachment having a configuration.

According to a second aspect of the present invention, there is provided a control device having a configuration in which the operating device according to the first aspect is electrically operated.

According to a third aspect of the present invention, the operating device according to the first aspect is hydraulic, and when the attachment is not operated by the hydraulic operating device, the pump load pressure is controlled by a pump swash plate for varying the flow rate. A control device for a construction machine with an attachment having a switching valve configured to supply a constant low pressure to a pump swash plate control regulator when the attachment is operated while supplying the regulator to the regulator.

[0009]

According to the first aspect of the present invention, when the detecting means detects that the operation device for the attachment is operated, it is stored in the target speed storage section in the control means by the external target speed switching device. select the one of the target rotational speed you are, control
The engine speed is adjusted to the target speed by controlling the speed variable means by the control means. At the same time, one of the target flow rates stored in the target flow rate storage unit in the control means is selected by an external target flow rate switch, and the control means controls the flow rate variable means to change the pump flow rate regardless of the pump load pressure.
Adjust to a constant target flow rate in all pressure ranges .

According to a second aspect of the present invention, the input from the detection means to the control means and the output from the control means to the rotation speed variable means and the flow rate variable means are performed electrically.

According to a third aspect of the present invention, when the attachment is operated by the hydraulic actuator, the switching valve is operated, and a constant low pressure is applied to the pump swash plate control regulator instead of the pump load pressure up to that time. Supplied to

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to a first embodiment shown in FIGS. 1 to 5 and a second embodiment shown in FIG.

(Embodiment 1) An embodiment in the case of an electric actuator will be described with reference to FIG.

In FIG. 1, reference numeral 1 denotes an electric operating device for an attachment which is operated by an operator. The operating device 1 may be not only the operation pedal shown but also an operation lever or an operation button. The operating device 1 includes a detecting means 1a such as a limit switch.
Is connected to one of the input terminals of the controller 2 as control means. One of the output terminals of the controller 2 is connected to an electromagnetic proportional valve 3 used as a flow rate varying means, and drives a pump swash plate servo 4.

The pump driving engine 5 is provided with a fuel injection pump 6, and the rotation speed of the engine 5 is controlled by controlling the fuel injection pump 6 via a fuel adjusting governor lever 6a by a motor 7 as a rotation speed varying means. Further, the rotation speed of the hydraulic pump 8 driven by the engine 5 is controlled.

Reference numeral 9 denotes a group of directional control valves for driving various hydraulic actuators, and one output port thereof is connected to an attachment (for example, a hydraulic hammer) 10. An electromagnetic proportional valve 11 connected to the output terminal of the controller 2 controls a directional control valve for driving and controlling the attachment 10, and an electromagnetic proportional valve 12 controls a directional control valve for driving and controlling an actuator other than the attachment. I do.

As shown in FIG. 2, the input signal processing section 2a of the controller 2 includes a detecting means 1a of the operating device 1.
At the same time, an operating device (for example, an operating lever) 13 for driving an actuator other than the attachment of the construction machine, and an accelerator dial 14 for giving an operator a target value of the number of rotations
And a pressure sensor 19 for detecting a pump discharge pressure.

As shown in FIG. 2, the input signal processing unit 2a of the controller 2 is connected to the output signal processing unit 2c via the operation unit 2b. A target rotation speed storage unit 2d and a target flow rate storage unit 2e are connected to the calculation unit 2b of the controller 2.

An external target rotation speed switch 21 for selecting one from a plurality of target rotation speeds stored in the storage unit 2d is connected to the target rotation speed storage unit 2d of the controller 2. The target flow rate storage unit 2e of the controller 2 has:
An external target flow rate switch 22 for selecting one from a plurality of target flow rates stored in the storage unit 2e is connected.

In such a configuration, when the operator operates the operating device 13 other than the attachment, the controller 2 drives the electromagnetic proportional valve 12 to move the actuator other than the attachment, such as a boom or a stick.

At this time, the controller 2 inputs a target rotation speed variable by the accelerator dial 14 as shown in FIG. 3A, and controls the motor 7 to set the engine rotation speed to the target rotation speed determined by the accelerator dial. To control. Also,
The controller 2 includes a pressure sensor as shown in FIG.
The pump discharge pressure is read through 19, and the pump flow rate is adjusted using the electromagnetic proportional valve 3 so that the pump torque becomes constant.

An operator 1 for attachment by an operator
Is operated, the controller 2 drives the electromagnetic proportional valve 11 to drive the attachment 10, and at the same time, inputs the set value of the target rotation speed switch 21 and the set value of the target flow rate switch 22, and the controller 2 is in the controller 2. From the target rotation speed storage unit 2d and the target flow rate storage unit 2e, a predetermined target rotation speed,
The target flow rate is selected, and the engine speed and the pump flow rate are fixed to optimal values for the attachment as shown in FIGS. 3 (B) and 4 (B). Where the pump flow
To fix the amount means as shown by a solid line in FIG.
All pump pressure ranges regardless of pump load pressure
Is to control to a fixed selected target flow rate.

FIG. 5 shows a flowchart of the control system according to the present invention, in which it is determined whether or not the operating device 1 has been depressed (S1).
When the operating device 1 is depressed, the target rotation speed selected by the target rotation speed switch 21 is fetched from the storage unit 2d of the controller 2 as control means (S2), and further selected by the target flow rate switch 22. The target flow rate is taken out from the storage unit 2e of the controller 2 (S3), and the motor 7 is used as a rotation speed variable means so as to obtain the target rotation speed and the target flow rate.
And output to the electromagnetic proportional valve 3 as the flow rate varying means (S
Four). On the other hand, if the operating device 1 is not depressed in S1, the target rotation speed is calculated from the accelerator dial 14 (S5), and the target flow rate is calculated using the detection value of the pump discharge pressure sensor 19 (S5).
6).

(Embodiment 2) Next, an embodiment in which a hydraulic operating device is used will be described with reference to FIG.

In FIG. 6, a hydraulic actuator (operation pedal) 1 for an attachment, a pump swash plate control regulator 4, drive ports 11 and 12 for a hydraulic directional control valve, and a hydraulic actuator (operation Since the levers 13 are hydraulic devices corresponding to the electric type, they are denoted by the same reference numerals. The hydraulic actuator 1 for the attachment is directly connected to the drive port 11, and the hydraulic actuator 13 other than the attachment is directly connected to the drive port 12.

A unique hydraulic type configuration that is not an electric type is a negative control relief valve 16 for controlling the pump flow rate, an electromagnetic proportional valve 17 as a flow rate variable means, a flow rate for an attachment or a flow rate for an actuator other than the attachment. And a detecting means 20 such as a pressure sensor or a pressure switch for detecting that the attachment operating device is operated.

The operation of the hydraulic embodiment of FIG. 6 will be described. When the operator operates an operating device 13 other than the attachment, the operating device 13 drives the directional control valve drive port 12 to drive another actuator such as a boom.

At this time, the pump flow rate is a negative control relief valve.
The upstream pressure of the pump 16 and the pump load pressure pass through the switching valve 18 and are input to the pump swash plate control regulator 4 to be determined.
The pump characteristic curve when the attachment is not operated is shown in FIG. Further, the engine speed becomes a value determined by the accelerator dial 14 as in the first embodiment, and FIG.
Is the engine characteristic curve when the attachment is not operated.

On the other hand, when the operator operates the attachment operating device 1, the operating device 1 drives the drive port 11 of the hydraulic directional control valve to drive the attachment 10. At this time, the controller 2 detects that the attachment has been operated by the detecting means 20 and switches the switching valve 18 to prevent the pump load pressure from entering the pump swash plate control regulator 4 and to output the signal from the controller 2. The pump flow rate can be controlled only by the pilot pressure supplied to the pump swash plate control regulator 4 via the switching valve 18 from the electromagnetic proportional valve 17 which is operated based on the received signal. Then, similarly to the first embodiment, the motor 7 is controlled to the target rotation speed and the target flow rate stored in the controller 2 in advance.
3 (B) and FIG.
As shown in (B), the engine speed and the pump flow rate are fixed to optimal values for the attachment.

[0030]

According to the first aspect of the present invention, when the operator operates the attachment operating device, the operation of the operating device is detected by the detecting means, and the target rotation speed switching device and the target flow rate switching device are detected. The target rotation speed and the target flow rate are selected from the target rotation speed storage unit and the target flow rate storage unit in the control means, and the rotation speed variable means is controlled by the control means.
Controlled and at the same time to adjust the engine speed to the target speed, adjusted to a constant eye <br/> target flow rate in all pressure ranges irrespective of pump flow rate by controlling the flow rate varying means to the pump load pressure by the control means It is possible to supply an optimal pump flow rate to the attachment which is not affected by the pump load pressure.

According to the second aspect of the present invention, it is possible to cope with the case where the operating device is of an electric type.

According to the third aspect of the invention, when the attachment is operated by the hydraulic operating device, the pump load pressure supplied to the pump swash plate control regulator is switched to a constant low pressure by the switching valve, and the pressure is applied to the attachment. Optimum pump flow is obtained.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an embodiment using an electric actuator showing a control device of a construction machine with an attachment according to the present invention.

FIG. 2 is a block diagram of the control device.

FIG. 3A is a graph showing an engine characteristic curve when the attachment is not operated in the control device, and FIG. 3B is a graph showing an engine characteristic curve when the attachment is operated in the control device.

FIG. 4A is a graph showing a pump characteristic curve when the attachment is not operated in the control device, and FIG. 4B is a graph showing a pump characteristic curve when the attachment is operated in the control device.

FIG. 5 is a flowchart showing a control method by the control device.

FIG. 6 is a circuit diagram of an embodiment using the hydraulic actuator of the present invention.

[Explanation of symbols]

 1,13 Operating device 1a, 20 Detecting means 2 Control means 2d Target speed storage unit 2e Target flow rate storage unit 3,17 Flow rate changing means 4 Pump swash plate control regulator 5 Engine 7 Speed changing means 8 Hydraulic pump 9 Directional control valve 10 Attachment 18 Switching valve 21 Target speed switch 22 Target flow switch

Claims (3)

(57) [Claims] 1. A construction with an attachment having a hydraulic pump driven by an engine, and a direction control valve for supplying oil discharged from the hydraulic pump to a hydraulic actuator according to an operating device operated by an operator while switching the direction. a machine, a detector operating device for attachment to detect that it is operated by the operator, the rotation speed varying means for variably adjusting the rotational speed of the engine to the target rotational speed and the fuel injection amount of the engine variable, hydraulic A flow rate variable means for variably adjusting a pump flow rate discharged from the pump to a target flow rate, and a target rotation speed storage section and a target flow rate storage section in which a target rotation number and a target flow rate are stored in advance, respectively.
When the signal of the detection means is input, the engine speed is
Outputs a signal to fix the target rotation speed to the rotation speed variable means
Together with the pump flow rate regardless of the pump load pressure.
A signal that fixes the target flow rate within the pressure range at a constant
Control means for outputting to a stage, a target speed switch for switching a plurality of target speeds set in the control means, and a target flow rate switch for switching a plurality of target flow rates set in the control means. A control device for construction machinery with attachments. 2. The control device for a construction machine with an attachment according to claim 1, wherein the operation device operated by the operator is of an electric type. 3. An operating device operated by an operator is a hydraulic type, and when the attachment is not operated by the hydraulic type operating device, the pump load pressure is supplied to a pump swash plate control regulator for variable flow rate and the attachment is operated. The control device for a construction machine with an attachment according to claim 1, further comprising a switching valve for supplying a constant low pressure to the pump swash plate control regulator when the switching is performed.