JPH06346490A - Controller for construction equipment with attachment - Google Patents

Abstract

PURPOSE:To enable control so as to obtain required flow rate of a pump regardless of load pressure of the pump. CONSTITUTION:When an operator operates an operating apparatus 1 for an attachment, a controller 2, to which the signal of a detecting means 1a is input, actuater a directional control valve 9, and supplys oil discharged from a hydraulic pump 8 driven by an engine 5 to the hydraulic-actuated attachment 10. One of the target number of revolution stored in a target revolution storage section in the controller 2 is selected by a target revolution changer 21, a revolution variable motor 7 is controlled and the fuel injection quantity of the engine 5 is varied, and the number of revolution of the engine is adjusted to be the target number of revolution at that time. One of target flow rates stored in a target flow storage section in the controller 2 is selected simultaneously by a target flow rate changer 22, an electromagnetic proportional valve 3 for varying a flow rate is controlled and a pump swash-plate servo 4 is driven, and the flow rate of the pump is adjusted to be the target flow rate regardless of the load pressure of the pump.

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, such as a hydraulic excavator 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 that an appropriate pump flow rate can be obtained according to the type of the attachment. Some attachments, such as hammers in hydraulic excavators, need to be driven at a constant pump flow rate. On the other hand, as disclosed in Japanese Utility Model Laid-Open No. 4-24636, there is an engine speed control device that controls only the engine speed using a signal that the attachment is operated.

In the control device described in this publication, when the use of the attachment is detected by the detection means, the target rotation speed set by the setting means according to the engine speed or the kind of the attachment that matches the driving force of the attachment. In order to obtain the above, the means for varying the fuel injection amount is controlled.

[0004]

The manual adjustment by the operator is not easy to obtain an appropriate pump flow rate,
Further, in the control device described in the above publication, the pump flow rate changes depending on the load pressure of the attachment due to the constant torque control function of a normal pump, and the constant pump flow rate, which is the original purpose, is supplied. I can't.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a control device for a construction machine with an attachment capable of controlling so as to obtain a required pump flow rate regardless of the pump load pressure. It is a thing.

[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 according to an operator operated by an operator. In a construction machine with an attachment having a directional control valve that supplies while switching, a detection unit that detects that the operator for the attachment is operated by an operator, and a variable fuel injection amount of the engine to change the engine speed. Rotation speed varying means for variably adjusting the target rotation speed, flow rate varying means for variably adjusting the pump flow rate to the target flow rate irrespective of the load pressure of the pump, and a target rotation speed for storing the target rotation speed and the target flow rate in advance, respectively. A storage unit and a target flow rate storage unit are provided inside, and the signal of the detection unit is input, and the rotation speed variable unit and the flow rate variable A control means for outputting a signal to the stage, a target rotation speed switcher for switching a plurality of target rotation speeds set in the control means, and a target flow rate switcher for switching a plurality of target flow rates set in the control means. It is a control device for a construction machine with an attachment having a configuration.

The invention described in claim 2 is a control device in which the operating device according to claim 1 is electrically operated.

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

[0009]

In the invention described in claim 1, when the detecting means detects that the attachment operating device has been operated, it is stored in the target rotational speed storage section in the control means by the external target rotational speed switching device. One of the target rotational speeds is selected, and the engine speed is adjusted to the target rotational speed by the rotational speed varying means. At the same time, one of the target flow rates stored in the target flow rate storage section in the control means is selected by the external target flow rate switch, and the flow rate varying means adjusts the pump flow rate to the target flow rate regardless of the pump load pressure.

According to a second aspect of the present invention, the detection means electrically inputs to the control means, and the control means electrically outputs the rotation speed varying means and the flow rate varying means.

According to the third aspect of the present invention, when the attachment is operated by the hydraulic actuator, the switching valve operates, and a constant low pressure is used instead of the pump load pressure until then. Is supplied to.

[0012]

The present invention will be described in detail below with reference to the first embodiment shown in FIGS. 1 to 5 and the second embodiment shown in FIG.

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

In FIG. 1, reference numeral 1 is an electric operating device for an attachment which is operated by an operator. The operating device 1 may be an operating lever or an operating button as well as the illustrated operating pedal. The operating device 1 is provided with a detecting means 1a such as a limit switch, and the detecting means 1a
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 a solenoid 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 number of revolutions 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 an assembly of directional control valves for driving various hydraulic actuators, one output port of which is connected to an attachment (for example, hydraulic hammer) 10. The solenoid 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 the solenoid proportional valve 12 controls a directional control valve for driving and controlling an actuator other than the attachment. To do.

As shown in FIG. 2, the input signal processing section 2a of the controller 2 has a detecting means 1a for the operating device 1.
In addition, an operating device (for example, an operating lever) 13 that drives an actuator other than the attachment of the construction machine, and an accelerator dial 14 that allows the operator to give a target value of the rotation speed.
And a pressure sensor 19 for detecting the 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 arithmetic unit 2b. The target rotation speed storage unit 2d and the target flow rate storage unit 2e are connected to the calculation unit 2b of the controller 2.

The target rotation speed storage unit 2d of the controller 2 is connected to an external target rotation speed switching unit 21 for selecting one from a plurality of target rotation speeds stored in the storage unit 2d. In addition, the target flow rate storage unit 2e of the controller 2
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 structure, when the operator operates the operating device 13 other than the attachment, the controller 2 drives the solenoid proportional valve 12 to move the actuators other than the attachment such as the boom and the stick.

At this time, the controller 2 inputs the target rotational speed which is changed by the accelerator dial 14 as shown in FIG. 3 (A), controls the motor 7 and sets the engine rotational speed to the target rotational speed determined by the accelerator dial. To control. Also,
The controller 2 is a pressure sensor as shown in FIG.
The pump discharge pressure is read through 19 and the pump flow rate is adjusted using the solenoid proportional valve 3 so that the pump torque is constant.

An operator operates the operation device 1 for attachment.
When the controller is operated, the controller 2 drives the solenoid proportional valve 11 to drive the attachment 10 and, at the same time, inputs the set value of the target rotation speed changer 21 and the set value of the target flow rate changer 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 to fix the engine speed and the pump flow rate to optimum values for the attachment as shown in FIGS. 3 (B) and 4 (B).

FIG. 5 shows a flow chart of the control system according to the present invention, in which it is judged whether or not the operating device 1 is stepped on (S1),
When the operation device 1 is stepped on, the target rotation speed selected by the target rotation speed switching device 21 is taken out from the storage unit 2d of the controller 2 as the control means (S2) and further selected by the target flow rate switching device 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 varying means so that the target rotation speed and the target flow rate can be obtained.
And output to the solenoid proportional valve 3 as a flow rate varying means (S
Four). On the other hand, if the operation 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 detected value of the pump discharge pressure sensor 19 (S5).
6).

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

In FIG. 6, a hydraulic operation device (operation pedal) 1 for an attachment, a pump swash plate control regulator 4, drive ports 11 and 12 of a hydraulic directional control valve, and a hydraulic operation device (operation) other than the attachment. The lever) 13 is a hydraulic type device corresponding to the electric type, and therefore, the same reference numeral is given. The hydraulic operating device 1 for attachment is directly connected to the drive port 11, and the hydraulic operating device 13 other than the attachment is directly connected to the drive port 12.

The unique hydraulic system which is not an electric system is a negative relief valve 16 for controlling the pump flow rate, an electromagnetic proportional valve 17 as a flow rate changing means, a flow rate for attachment or a flow rate for an actuator other than the attachment. A switching valve 18 for selecting whether or not, and a detection means 20 such as a pressure sensor or a pressure switch for detecting that the attachment operation device is operated.

The operation of the hydraulic embodiment of FIG. 6 will be described. When the operator operates the 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 the negative control relief valve.
The upstream pressure of 16 and the pump load pressure pass through the switching valve 18, are input to the pump swash plate control regulator 4, and are determined.
The pump characteristic curve is shown in (A) when the attachment is not operated. Further, the engine speed becomes a value determined by the accelerator dial 14 as in the case of the first embodiment.
The engine characteristic curve is shown 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, switches the switching valve 18 to prevent the pump load pressure from entering the pump swash plate control regulator 4, and outputs 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 solenoid proportional valve 17 which operates based on the signal. Then, as in the case of the first embodiment, the motor 7 is controlled so that the target rotation speed and the target flow rate stored in advance in the controller 2 are achieved.
3B and FIG. 4 by controlling the solenoid proportional valve 17.
As shown in (B), the engine speed and the pump flow rate are fixed to optimum values for the attachment.

[0030]

According to the first aspect of the present invention, when the operator operates the attachment operation device, the detection means detects that the operation device is operated, 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 engine speed is adjusted to the target rotation speed by the rotation speed varying means, and at the same time, the pump flow rate is adjusted by the flow rate changing means. The target flow rate can be adjusted regardless of the pump load pressure, and the optimum pump flow rate that is not affected by the pump load pressure can be supplied to the attachment.

According to the invention of claim 2, it is possible to cope with the case where the operating device is an electric type.

According to the third aspect of the present invention, when the attachment is operated by the hydraulic operation 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 attachment is operated. Optimal pump flow rate is obtained.

[Brief description of drawings]

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

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

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

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

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

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

[Explanation of symbols]

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

Claims (3)

[Claims] 1. A construction with an attachment, comprising: a hydraulic pump driven by an engine; and a directional control valve that supplies oil discharged from the hydraulic pump to a hydraulic actuator while switching the direction according to an operating device operated by an operator. In the machine, a detection unit that detects that an attachment operation unit is operated by an operator, a rotation speed variable unit that variably adjusts the engine rotation speed to a target rotation speed by changing the fuel injection amount of the engine, and a pump A flow rate changing means for variably adjusting the pump flow rate to the target flow rate regardless of the load pressure of the target, and a target rotation speed storage section and a target flow rate storage section for storing the target rotation speed and the target flow rate in advance, respectively.
Control means for inputting the signal of the detection means and output for the rotation speed varying means and the flow rate varying means, a target rotation speed switching device for switching a plurality of target rotation speeds set in the control means, and a control means Control device for a construction machine with an attachment, comprising: a target flow rate switch that switches a plurality of target flow rates. 2. The control device for a construction machine with an attachment according to claim 1, wherein the operation device operated by the operator is an electric type. 3. An operator operated by an operator is a hydraulic type, and when the attachment is not operated by the hydraulic type operator, the pump load pressure is supplied to a pump swash plate control regulator for varying the flow rate and the attachment is operated. The control device for the construction machine with an attachment according to claim 1, further comprising a switching valve that supplies a constant low pressure to the pump swash plate control regulator when the operation is performed.