JPH10281112A - Fluid control method and device thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid control device to reliably stop the feed of hydraulic oil to a hydraulic actuator when a controller is in a non-operation state. SOLUTION: Hydraulic oil discharged from a hydraulic pump 33 driven by an engine 31 is controlled by a control valve 35 controlled by a controller 45 and fed to a hydraulic actuator 37. An operating state in which the hydraulic actuator 37 is operated is detected by a pressure sensor 51 for detecting a load pressure. When the controller 45 is in a non-operation state and the operating state of the actuator is detected by the pressure sensor 51, an engine cut-off signal is outputted from a controller 46. A control means 54 which receives the engine cut-off signal from the controller 46 stops the fed of fuel to the injection pump 55 of an engine 55 and operates a governor motor to a stop position. This constitution stops the engine 31, stops the hydraulic pump 33, and stops the feed of hydraulic oil to the hydraulic actuator 37.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling a fluid characterized by stopping the operation of a hydraulic pump.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional fluid control device. This device is connected to the pilot primary line 12 of the pilot pump 11
Is connected to an input port of a proportional solenoid valve 14 via a solenoid valve 13, and an output port of the proportional solenoid valve 14 is connected to pilot pressure acting portions 16a and 16b of a control valve 16 via pilot secondary lines 15a and 15b. The control valve 16
The supply of hydraulic oil from a main pump 18 driven by an engine 17 is performed, and the direction and flow rate of hydraulic oil supplied to a hydraulic actuator 19 are controlled. The illustration of the return oil side circuit of the hydraulic actuator 19 is omitted.

The proportional solenoid valve 14 receives a current output from the controller 21 to a signal line 23 in accordance with an operation amount of an operating device (electronic joystick) 22 connected to the controller 21, and operates proportionally to change the current value. Accordingly, the pilot secondary pressure output to the pilot secondary lines 15a and 15b is controlled, and the control valve 16 is operated as a pilot.

When the hydraulic actuator 19 is, for example, a traveling motor of a crawler type vehicle, the solenoid valve 13 is erroneously transmitted from the control valve 16 to the traveling motor even though the operating device 22 is not operated. This is provided to prevent the vehicle from running when the hydraulic oil is output. When such a vehicle is running, the operator is required to output the primary pressure cutoff signal (current ), The solenoid valve 13 is switched, the pilot pressure supplied from the pilot pump 11 to the control valve 16 via the proportional solenoid valve 14 is cut off, and the control valve 16 is returned to the neutral position.

[0005]

According to this conventional fluid control device, for example, even when the operating device 22 is not operated, an error current runs through the proportional solenoid valve 14 or another corresponding solenoid valve. Sometimes, or when the pilot primary pressure is connected to both ends of the stem (spool) of the solenoid valve, when the pressure balance is lost due to damage inside the valve, unless the operator switches the solenoid valve 13, There is a problem that the vehicle may run even when the operation device 22 is not operated.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a fluid control method and a fluid control device capable of reliably stopping supply of fluid to a fluid pressure actuator when an operating device is not operated. It is intended for.

[0007]

According to a first aspect of the present invention, there is provided a fluid pressure actuator in which a fluid discharged from a fluid pressure pump driven by an engine is controlled by a control valve operated by an operation device. In the fluid control method for supplying fluid to a hydraulic actuator, when the operating device is in the non-operating state and the actuator is in the operating state in which the hydraulic actuator operates, the driving of the hydraulic pump by the engine is stopped, and This is a fluid control method for stopping the operation.

[0008] Even if the operating device is not operated,
When the hydraulic actuator is in an actuator operating state, the operation of the hydraulic pump is stopped by stopping the engine itself or interrupting the transmission of driving force from the engine to the hydraulic pump. Stop fluid supply to

According to a second aspect of the present invention, in the fluid control method according to the first aspect, the driving of the fluid pressure pump is stopped by shutting off fuel supply to the engine and stopping the engine.

Then, the fuel supply function of the engine itself is stopped, and the engine is stopped to stop the supply of fluid to the hydraulic actuator.

According to a third aspect of the present invention, there is provided a fluid control apparatus for supplying a fluid discharged from a fluid pressure pump driven by an engine to a fluid pressure actuator by controlling the fluid by a control valve operated by an operation device. A sensor for detecting an actuator operation state in which the fluid pressure actuator operates, a controller for outputting an engine cutoff signal when the operating device is in a non-operation state and the sensor detects the actuator operation state, and an engine cutoff signal from the controller. And control means for stopping driving of the fluid pressure pump by the engine in response to the request.

[0012] Even when the operating device is not operated,
When in the actuator operating state in which the fluid pressure actuator operates, the state is detected by a sensor, and an engine shutoff signal is output from the controller to the control means,
By stopping the engine itself or interrupting the transmission of the driving force from the engine to the hydraulic pump by this control means, the driving of the hydraulic pump is stopped and the supply of fluid to the hydraulic actuator is stopped.

According to a fourth aspect of the present invention, in the fluid control device according to the third aspect, the sensor is provided in at least one of an electric circuit for electrically controlling the control valve and a fluid circuit for controlling the fluid pressure actuator. It was done.

[0014] Even when the operating device is not operated,
The fact that the fluid pressure actuator is in the actuator operating state is, for example, a state in which an error current runs on an electromagnetic valve of an electric circuit for electrically controlling the control valve, or a state in which the load pressure of the fluid pressure actuator is raised, or a state in which the fluid A state in which the pilot secondary pressure of the fluid circuit that controls the pressure actuator has changed or a state in which the delivery pressure has changed is detected by a sensor, and the supply of fluid to the fluid pressure actuator is stopped.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to one embodiment shown in FIGS. 1 and 2 and another embodiment shown in FIG.

As shown in FIG. 1, a variable displacement hydraulic pump 33 as a fluid pressure pump is connected to an output shaft 32 of a diesel engine (hereinafter simply referred to as an engine 31).
A supply port of an electromagnetically operated control valve 35 is connected to a discharge line 34 of the hydraulic pump 33, and an output port of the control valve 35 is connected to a hydraulic cylinder via an output line 36,
A fluid pressure actuator such as a hydraulic motor (hereinafter, referred to as a hydraulic actuator 37) is connected.

When the control valve 35 is, for example, a closed center, the output lines of a plurality of hydraulic actuators 37
A load pressure detection line 41 for detecting a load pressure (load sensing pressure) is drawn out from 36, and a load pressure detection line 43 integrated by a shuttle valve 42 is connected to a load sensing regulator 44 of the hydraulic pump 33. The discharge amount of the hydraulic pump 33 is variably controlled by 44.

The control valve 35 is electrically controlled by a controller 46 which receives an operation signal transmitted from an operation device (electronic joystick) 45 and transmits an output signal.
For this purpose, a control signal line 47 and a solenoid 48 are provided, and the hydraulic oil discharged from the hydraulic pump 33 is supplied to the hydraulic actuator 37 after being controlled in direction and flow by the control valve 35.

Control valve 35, hydraulic actuator 37
And only one set of the operation device 45 is shown,
A plurality of sets are provided.

The load pressure detection line 43 is provided with a pressure sensor 51 as a sensor for detecting a load pressure state as an actuator operation state when one of the plurality of hydraulic actuators 37 is operated. From 51, a signal acquisition line 52 is connected to the controller 46.

The controller 46 is configured such that the operating device 45 is not operated and the pressure sensor 51 is
Has a function of outputting an engine shut-off signal to the engine 31 when the operating state of the engine, that is, the state with the load pressure is detected, and is provided with an engine shut-off signal line 53 for that purpose.

On the other hand, the engine 31 has an ignition pump (fuel injection pump) 55 having control means (for example, a stop lever) 54 for stopping the driving of the hydraulic pump 33 by the engine 31 in response to an engine shut-off signal from the controller 46. Have.

The control means 54 of the ignition pump 55
In response to a stop signal from the controller 46, the solenoid valve provided in the fuel supply path is operated to forcibly shut off the fuel supply to the fuel delivery plunger, and the governor motor is operated to control the fuel delivery plunger. Move the rack to the fuel supply stop position.

Next, the operation of the embodiment shown in FIG. 1 will be described with reference to FIG. In FIG. 2, circled numbers indicate step numbers.

(Step 1) A plurality of hydraulic actuators such as a traveling hydraulic actuator (hydraulic motor) and a working machine hydraulic actuator (boom cylinder, arm cylinder, bucket cylinder) from a common hydraulic pump 33 using, for example, a hydraulic shovel. When supplying hydraulic oil to 37, it is determined whether or not all of the operating devices 45 corresponding to the respective hydraulic actuators 37 are in a non-operating state, that is, in a neutral state.

(Step 2) When even one operating device 45 is in the operating state (NO in step 1), the controller 46
Executes a normal electronic control program.

(Step 3) When all the operation devices 45 are in the non-operation state (YES in Step 1), the load pressure P _LS detected by the pressure sensor 51 becomes equal to the set pressure (for example, 5 kgf / cm ^2).
Is determined.

[0028] (Step 4) when in the actuator operation state by the load pressure P _LS on either set pressure of the hydraulic actuator 37 (YES in Step 3), the controller 46 detects this state by the pressure sensor 51, the operation It is automatically determined that the actuator 45 is in the operation state despite the non-operation state of the switch 45, and an engine shutoff signal is outputted to the control means 54 for stopping the engine.

When a stop signal is input, the control means 54 shuts off the fuel supply to the fuel delivery plunger of the ignition pump 55 by the solenoid valve, and simultaneously operates the governor motor to stop the fuel supply of the control rack of the fuel delivery plunger. Move to position.

(Step 5) At the same time, an error message is displayed to the operator.

(Step 6) As described above, the engine 31 is stopped by stopping the fuel supply function of the engine itself, and the fuel supply to the engine 31 is stopped, so that the drive of the hydraulic pump 33 is also stopped. Stop supply of hydraulic oil to 37.

Thus, for example, the hydraulic actuator 37
Is a traveling hydraulic motor that drives a crawler belt of a construction machine, it is possible to prevent traveling that is contrary to the intention of the operator.

Next, another embodiment of the present invention will be described with reference to FIG. In the embodiment shown in FIG. 3, FIG.
The same parts as in the conventional example shown in FIG.

An operating device (electronic joystick) 22 controls hydraulic oil discharged from a main pump 18 driven by an engine 17 by a controller 21 and a control valve 16 that is pilot-operated via a proportional solenoid valve 14, A circuit for supplying a hydraulic actuator 19 as a fluid pressure actuator is provided as shown in FIG.
Proportional solenoid valve 14, control valve 16, hydraulic actuator
Although only one set is shown, a plurality of sets 19 and operating devices 22 are provided.

The following are provided as sensors for detecting the actuator operating state in which the hydraulic actuator 19 operates.

For example, from the controller 21 as an electric circuit for electrically controlling the control valve 16, a proportional solenoid valve is provided.
A current sensor 61 for detecting a state in which the error current has run is provided on the signal line 23 to 14.

In the output line from the control valve 16 to the hydraulic actuator 19, a pressure sensor 62 for detecting a state in which the load pressure of the hydraulic actuator 19 has risen is provided.

Further, the proportional solenoid valve 14 to the control valve
A pressure sensor 63 for detecting a state in which the pilot secondary pressure output from the proportional solenoid valve 14 has changed is provided to the pilot secondary lines 15a and 15b to the 16 pilot pressure action sections 16a and 16b.
Is provided via a shuttle valve 64.

Each of these sensors 61, 62, 63 is connected to the controller 21 by a signal take-in line 65, 66, 67, and inputs an error current, a load pressure or a pilot secondary pressure to the controller 21, respectively.

The controller 21 has a function of outputting an engine shut-off signal when any one of the sensors 61, 62, 63 detects an actuator operation state even though all the operation devices 22 are in the non-operation state. And an engine shutoff signal line 68 for this purpose.

The engine 17 is provided with an ignition pump (fuel injection pump) 70 having a control means (for example, a stop lever) 69 for stopping the driving of the main pump 18 by the engine 17 in response to an engine cutoff signal from the controller 21. I have.

The control means 69 is similar to the control means 54 shown in FIG. 1, and a description thereof will be omitted.

Next, the operation of the embodiment shown in FIG. 3 will be described. When all the actuators 22 are in the non-operating state, that is, in the neutral state, when any of the hydraulic actuators 19 is in the operating state. The state is detected by any of the sensors 61, 62, 63.

That is, a state where an error current has run through the circuit for electrically controlling the proportional solenoid valve 14 for pilot-operating the control valve 16
The state in which the load pressure of the actuator has risen or the state in which the pilot secondary pressure from the proportional solenoid valve 14 has changed indicate the actuator operating state, so that all the operating devices 22 are in the non-operating state. Regardless, the state in which an error current ran in the control circuit of the proportional solenoid valve 14 is indicated by the current sensor 61, the state in which the load pressure has risen is indicated by the pressure sensor 62, and the state in which the pilot secondary pressure has changed is indicated by the pressure sensor 63, respectively. To detect.

When such an abnormality is detected, the controller 21 outputs an engine shutoff signal to the control means 69, and the control means 69 stops the fuel supply to the ignition pump 70, thereby stopping the engine 17. Thus, the driving of the main pump 18 is stopped, the supply of the hydraulic oil to the hydraulic actuator 19 is stopped, and the operation such as running of the vehicle is stopped.

It should be noted that even if all the operating devices 22 are in the non-operating state, an abnormality in which one of the hydraulic actuators 19 is in the operating state of the actuator is caused by a delivery pressure (a pump discharge pressure or the like) of a fluid circuit that controls the hydraulic actuator 19. ) May be detected by a pressure sensor (not shown) to perform the stop control.

As shown in the above embodiments, the sensor for detecting the operating state of the actuator in which the fluid pressure actuator operates may be provided in an electric circuit for electrically controlling the control valve. It may be provided in the fluid circuit to be controlled.

Further, in the above embodiment, the engine is stopped by the control means. However, the transmission of the driving force from the engine to the hydraulic pump is performed while the engine is rotating, for example, by disengaging the clutch. By shutting off, the drive of the hydraulic pump by the engine is stopped,
The fluid supply to the hydraulic actuator may be stopped.

Further, the present control device can be employed not only in a closed center but also in an open center. When the control valve is an open center, it is necessary to detect the pressure of each hydraulic actuator or a negative control pressure for pump control (so-called negative control pressure) or a positive control pressure (positive control pressure) instead of the load pressure.

Finally, the present invention is effective when used in a crawler-type traveling device of construction equipment such as a hydraulic shovel or a loader, but is not limited to such construction equipment. Can be widely applied to fluid control devices that operate

[0051]

According to the first aspect of the present invention, even when the operating device is in the non-operating state, when the hydraulic actuator is in the operating state of the actuator, the driving of the hydraulic pump by the engine is stopped. Fluid supply to the hydraulic actuator can be reliably stopped, thereby preventing unexpected operation of a vehicle, a working machine, or the like that is moved by the hydraulic actuator.

According to the second aspect of the present invention, since the drive of the fluid pressure pump is stopped by stopping the fuel supply to the engine and stopping the engine, the fuel supply function of the engine itself is effectively utilized. The driving of the fluid pressure pump can be stopped.

According to the third aspect of the present invention, even when the operating device is in the non-operating state, when the fluid pressure actuator is in the operating state, the sensor for detecting the operating state of the actuator and the engine shut-off signal are output. Controller and the control means for stopping the drive of the hydraulic pump by the engine, the supply of fluid to the hydraulic actuator can be stopped reliably, and unexpected operation of vehicles and working machines, etc., which are moved by the hydraulic actuator is reliably prevented. it can.

According to the fourth aspect of the invention, in each of the electric circuit and the fluid circuit, the non-operating state of the operating device and the operating state of the actuator are detected by the sensor.
The fluid supply to the fluid pressure actuator can be stopped.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a fluid control device according to the present invention.

FIG. 2 is a flowchart showing one embodiment of a fluid control method according to the present invention.

FIG. 3 is a circuit diagram showing another embodiment of the fluid control device according to the present invention.

FIG. 4 is a circuit diagram showing a conventional fluid control device.

[Explanation of symbols]

31 Engine 33 Hydraulic pump as hydraulic pump 35 Control valve 37 Hydraulic actuator (hydraulic actuator) 45 Actuator 46 Controller 51 Pressure sensor as sensor to detect actuator operating state 54 Control means (stop lever)

Claims (4)

[Claims] 1. A fluid control method for supplying a fluid discharged from a fluid pressure pump driven by an engine to a fluid pressure actuator by controlling the fluid by a control valve operated by a manipulation device, wherein the manipulation device is in a non-operation state. And a fluid control method, wherein when the actuator is in an operating state in which the fluid pressure actuator is operated, the driving of the fluid pressure pump by the engine is stopped, and the supply of fluid to the fluid pressure actuator is stopped. 2. The fluid control method according to claim 1, wherein the drive of the fluid pressure pump is stopped by stopping the fuel supply to the engine and stopping the engine. 3. A fluid control device for supplying a fluid discharged from a fluid pressure pump driven by an engine to a fluid pressure actuator while controlling the fluid by a control valve operated by an operation device, wherein the fluid pressure actuator operates. A sensor for detecting an operation state of the actuator, a controller for outputting an engine cutoff signal when the actuator is in an inoperative state and the sensor detecting the operation state of the actuator, and a hydraulic pump driven by the engine in response to the engine cutoff signal from the controller Control means for stopping the drive of the fluid control device. 4. The fluid control device according to claim 3, wherein the sensor is provided in at least one of an electric circuit for electrically controlling the control valve and a fluid circuit for controlling the fluid pressure actuator.