JP3144962B2 - Valve control device for hydraulic actuator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve control device for a hydraulic actuator in a hydraulic circuit used for a machine such as a construction machine.

[0002]

2. Description of the Related Art In general,
This type of hydraulic circuit is configured such that the switching of the supply of hydraulic oil to an actuator such as a hydraulic cylinder or a hydraulic motor is performed by switching a main valve, and the switching of the main valve is provided in a pilot oil passage. In some cases, this is performed by switching the pilot valve means. By the way, in this apparatus, in order to save labor, automatic switching control of the pilot valve means is performed to activate the actuator.
Although an attempt is made to automate the operation, it is not preferable to completely eliminate the operation by the manual operation tool. Therefore , it is set so that both can be controlled. For this reason, the pilot valve means is connected to the manual operation. Pilot valve means for manual control in which valve path switching is performed,
Valve path switching undergoing automatic control command from the pilot control unit is Ru Monogaa that the automatic control pilot valve means is provided to be made.

[0003] In the automatic control state of the actuator, when the actuator has or abnormality detection or reached operating limit, can be automatically controlled to perform an emergency stop actuation stop of actuator based on the detected known,
When the manual operation is performed, most of the operation depends on the feeling of the operator, and there is a possibility that the supply of the pressurized oil to the actuator may be continued even when the operation limit is reached.

Therefore, it has been proposed to automatically switch the pilot oil passage to stop the manual control when the operation limit state or the like is reached during the manual control. However, for that purpose, during manual control,
It is necessary to provide the valves means for stopping in preference to work
However, the conventional one is a manual
The valve means for stopping at the time of control is required separately from the pilot valve means for manual control and the pilot valve means for automatic control , so that the structure is complicated and the number of parts is increased. .

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to provide a valve control device for a hydraulic actuator which can eliminate these disadvantages in view of the above-mentioned circumstances. A main valve for manually controlling the actuator in the pilot oil passage for switching the main valve that switches the supply of pressure oil to the actuator
Provided corresponding to a pair of pilot chambers provided in
No alternative valve switching based on the operation of the manual operation tool
A pair of first pilot valves and an actuator
Automatic operation without manual operation
Pie output when the control start switch is turned ON
Automatically set based on a control command from the lot control unit
Pilot room of main valve based on dynamic control system
Pilot valve for automatic control that supplies pilot pressure oil to the
Means for manual and automatic control of the actuator.
Hydraulic activator configured to be able to select each
In the valve control device for a heater, the pilot
An actuator is preset in the oil passage during manual control
No further action is taken in response to the detection of
In order to stop the supply of pressure oil to the tutor,
In configuring to switch the Ilot oil passage,
The pilot valve means for automatic control is
A pair is provided corresponding to the Ilot room, pilot control
Pilot for automatic control in response to manual control command from
Close the oil passage and open the pilot oil passage for manual control.Manual control
For manual control after receiving the first position and automatic control command
The pilot oil passage is closed and the pilot oil passage for automatic control is opened.
The valve is switched to the second position where automatic control can be performed.
A third pilot valve configured to
Inlet oil of pilot pressure oil for automatic control of pilot valve
Connected to the merged oil passage where the
Receiving the manual control command, the junction oil passage is connected to the oil tank side.
The first position and the automatic control command
Valve switching with the second position for supplying pilot pressure oil for dynamic control
And a second pilot valve configured to perform
And the pilot control unit includes the manual control.
Control based on the detection of the operation stop state.
From the first position to the second position with respect to the third pilot valve
Manual control to stop manual control by outputting valve switching command to
It is characterized by having a priority stop means at the time of control .

[0006] The present invention is, Yotsute to this configuration, Aku
The pilot valve means for automatic control required for automatic control of the timer is stopped prior to manual control during manual control
The valve means for preferential stop at the time of manual control can be effectively used as it is so that automatic preferential stop at the time of manual operation can be performed.

[0007]

Next, an embodiment of the present invention will be described with reference to the drawings. In the drawings, reference numeral 1 denotes a hydraulic shovel, and the hydraulic shovel 1 is connected to a crawler-type traveling section 2, a pivoting section 3 which is pivotably supported above the traveling section 2, and a front part of the pivoting section 3. A working unit 4 is provided, and all of these basic configurations are conventional.

The working part 4 is composed of various parts such as a boom 5, an arm 6, a bucket 7, and the like, and is based on expansion and contraction operations of various hydraulic cylinders 11, such as an arm cylinder 8, a boom cylinder 9, and a bucket cylinder 10. These hydraulic cylinders 11 correspond to the actuator of the present invention, and the present invention is embodied in a valve control device for switching the operation.

That is, the hydraulic cylinder 11 opens and closes an oil passage from the main pump 13 to the cylinder extension side or the cylinder contraction side based on the switching operation of the main valve 12, thereby performing the expansion and contraction operation. The main valve 12 is a spring-neutral return-type six-port three-position switching valve, the switching operation of which is performed by pilot pressure oil, and the supply of the pilot pressure oil. As will be described later, the apparatus is configured so that manual control by operation of a manual operation tool 14 such as an operation lever and automatic control by a command from the pilot control unit 15 can be performed.

[0010] The pilot pressure oil is supplied to the main valve 12.
Are supplied to the expansion-side pilot chamber 12E or the contraction-side pilot chamber 12R provided in the first, second, third, and fourth pilot chambers 12E and 12R, the pilot pump 16 and the oil tank 17, respectively. Second and third pilot valves 18, 19, 20 are provided. Here, the first pilot valve 18, the Pyro
The expansion-side first pilot valve 18E and the reduction-side first pilot valve 18R correspond to the cut chambers 12E and 12R .
A pair, and the first pilot valve 18E or 18R of the engineered side in accordance with the operation amount of the manual operating member 14 is configured to be switched alternatively. On the other hand, each of the second pilot valve 19 and the third pilot valve 20 is a two-position switching type solenoid valve that is switched based on a control command from the pilot control unit 15, and the third pilot valve 20 is a real one. Invention
One of pilot valve means for automatic control
In this case, the pilot chambers correspond to the pilot chambers 12E and 12R.
Correspondingly, it is constituted by a pair of an extension-side third pilot valve 20E and a reduction-side third pilot valve 20R.

Furthermore, the although the pilot valve is as it has a three port any, each port 18Ea of the first pilot valve 18 E, 18Eb, 18E
c is connected to the pilot pump 16, the oil tank 17, and the port 20Ea of the third pilot valve 20E, respectively. The ports 18Ra, 18Rb, and 18Rc of the first pilot valve 18R are connected to the pilot pump 1
6, the oil tank 17, and the port 20Ra of the third pilot valve 20R. On the other hand, the second pilot valve 19 is a pilot valve for automatic control according to the present invention.
And the other port of this means.
Reference numerals 9a and 19b are connected to the pilot pump 16 and the oil tank 17, respectively, and a port 19c is connected to an oil passage that branches on the way to the ports 20Eb and 20Rb of the third pilot valves 20E and 20R. . One
Each port 2 of the Mari third pilot valve 20E, 20R
0 Eb, the oil passage from 20Rb is connected to the merged oil passage
Is tied. Further, a third pilot valve 20E,
The ports 20Ec and 20Rc of the 20R are connected to the pilot chamber 1
2E and the pilot chamber 12R.

Next, the valve path switching operation of each of the pilot valves will be described. First pilot valve 18
As described above, the first pilot valve 18E or 18R on the side on which the manual operation tool 14 is operated can be selectively switched, but on the switched side, the first pilot valve 18E or 18R can be switched from the pilot pump 16 to the third pilot valve. Pilot valve 2
Valve passage leading to 0E or 20R is switched from the closed formation in an open state, and the third pilot valve 20E or 20
Valve passage leading from the R to the oil tank 17 is summer to be switched from the open formation in a closed state. Here, 21E is a pressure switch provided in a circuit from the extension-side first pilot valve 18E to the extension-side third pilot valve 20E.
The 21R an alien pressure switch provided in the oil passage leading to the reduction side third pilot valve 20 R from the first pilot valve 18 R contracting side, pressure switches 21E, 21
The signal from R is input to the pilot control unit 15. Then, the pressure switches 21E, 21
When the pressure in the oil passage provided with R becomes equal to or higher than a predetermined value, that is, when the first pilot valve 18E or 18R is switched by the operation of the manual operating tool 14, the
6 to the third pilot valve 20E or 20R on the side
When the oil pressure reaches a predetermined pressure due to the opening of the oil passage leading to the pressure switch 21E or 21R, the pressure switch 21E or 21R detects this and outputs a detection signal to the pilot control unit 15, and The pressure switch 21
When the detection signals from E and 21R are input, the pilot control unit 15 is set to determine that the state is the manual control state.

On the other hand, the second pilot valve 19 is switched on the basis of the command from the pilot control unit 15 as described above. However, the pilot pump unit 15 is switched from manual to automatic control by the pilot pump. 16 to the third pilot valves 20E and 20R are closed, and the third pilot valves 20E and 20R are closed.
From the first position where the valve path leading to the oil tank 17 is opened, the valve path leading from the pilot pump 16 to the third pilot valve 20E, 20R is open, and the third pilot valve 20E, 20R leads to the oil tank. The valve path leading to 17 is switched to a second position in which it is closed.

The third pilot valve 20 also has
The switching is performed based on a command from the pilot control unit 15, and when the command from the pilot control unit 15 is switched from the manual control to the automatic control state, the hydraulic pressure among the expansion-side and reduction- side pilot valves 20E and 20R is changed. Cylinder 11
Only the third pilot valve 20E or 20R on the side corresponding to the operation of the valve is switched, and the valve that connects the first pilot valve 18E or 18R to the pilot chamber 12E or 12R on the switched side. The first pilot valve 1 is moved from the first position where the path is open and the valve path connecting the second pilot valve 19 and the pilot chamber 12E or 12R is closed.
The valve is switched to a second position in which the valve path connecting the 8E or 18R to the pilot chamber 12E or 12R is closed, and the valve path connecting the second pilot valve 19 and the pilot chamber 12E or 12R is open. It is becoming possible to be.

On the other hand, reference numeral 22 denotes a stroke sensor (corresponding to an operation stop detecting means of the present invention) provided in the hydraulic cylinder 11 so that a detection signal of the stroke sensor 22 is inputted to the pilot control unit 15. I'm sorry. Then, in the manual control state, the pilot control unit 15 sets the detection value input from the stroke sensor 22 to the expansion / contraction limit value of the hydraulic cylinder 11 (the expansion / contraction limit value is adjusted by an operator by adjusting a setting device or the like. If it is possible to arbitrarily change the value to a desired value, there is an additional advantage that the workability is improved.) When the value reaches the extension limit value, the extension-side third pilot valve 20E is connected to the extension-side third pilot valve 20E. On the other hand, if it is the reduction limit value, a priority stop command is output to the reduction- side third pilot valve 20R in preference to the manual control command,
And a third pilot valve 20E or 20R on the side where the priority stop command is outputted is set to be switched to the second position from the first position described above. In the drawing, 24 is a hydraulic motor, 25 is an oil tank , and 26 is an automatic control.
This is the start switch .

In the embodiment of the present invention configured as described above, the expansion and contraction operation of the hydraulic cylinder 11 is performed by the main valve 12.
The supply of the pilot pressure oil for switching the main valve 12 is performed by selecting either manual control or automatic control. This control procedure will be described based on a flowchart shown in FIG. First, a main switch (key switch) (not shown) is turned ON, and the pilot control unit 15 is system-started and initialized. When the pilot switch 15 is initialized, it is determined whether a detection signal has been input from one of the pressure switches 21E and 21R. Done. If there is no input of any detection signal, it is further determined whether or not the automatic control start switch 26 has been turned ON.
When N operations are performed, the actuator is automatically controlled in accordance with a preset automatic control system. On the other hand, In no event any one of the pressure switches 21E by operating the manual operating member 14, the detection signal from the 21R is determined to be input now, this pressure switch 2
When a is determined is from 1E, the detection value of whether reaches the elongation limit determined from the stroke sensor 22 is made, when it is determined not to reach the extension limit value, The third pilot valve 20E is maintained at the first position side , and when it is determined that the extension limit value has been reached, a priority stop command is output to switch the third pilot valve 20E to the second position side. . If it is determined that the detection signal is from the pressure switch 21R, it is determined whether the detection value from the stroke sensor 22 has reached the reduction limit value, and it is determined that the detection value has not reached the reduction limit value. When this is done, the third pilot valve 20R is maintained at the first position side, and when it is determined that the reduction limit value has been reached, a priority stop command is output to switch the third pilot valve 20R to the second position side. It is like that.

Next, with reference to the hydraulic circuit diagrams shown in FIGS. 3 to 5, for example, when the manual operation tool 14 is operated to the extension side, the first pilot valve 18E is switched and the pilot pump 16 Pilot valve 2
The oil passage leading to 0E is opened. Along with this, the detection signal from the pressure switch 21E is sent to the pilot control unit 1
5, and the pilot control unit 15 determines that the state is the manual control state. On the other hand, the third pilot valve 20E
Receives the manual control command from the pilot control unit 15 and sends the pilot chamber 12 through the first pilot valve 18E.
The valve path to E is switched to the first position where it is opened, whereby the pilot pressure oil is supplied from the pilot pump 16 to the pilot chamber 12E via the first and third pilot valves 18E and 20E, and the main valve is opened. 12 is switched to the cylinder extension side.

On the other hand, when the operation of the manual operation tool 14 is not performed and the automatic control status switch 26 is turned ON, the pilot control unit 15 determines that the automatic control state is established. In the automatic control state of the actuator, when the content of the automatic control command is, for example, a command to automatically extend the cylinder, the valve path from the pilot pump 16 to the third pilot valve 20E, 20R is transmitted to the second pilot valve 19. Outputs an automatic control command to switch to the second position where the valve is opened, and switches to the second position where the valve path from the second pilot valve 19 to the pilot chamber 12E is opened with respect to the third pilot valve 20E. Thus, an automatic control command is output, whereby the second and
Pilot pressure oil is supplied to the pilot chamber 12E via the third pilot valves 19 and 20E, and the main valve 1
2 automatically switches to the cylinder extension side.

[0019] In contrast, in the manual control to try to stretch the cylinder length, when the detection value from the stroke sensor 22 in the pilot control unit 15 is judged to be extended limit value, the pilot control unit 15 1st position
A priority stop command is output to the third pilot valve 20E, which has been instructed to maintain the third pilot valve 20E, whereby the third pilot valve 20E is switched from the first position to the second position. one pilot valve passage is in the closed formation state and Natsute from the valve 18E to the pilot chamber 12E, the
While the supply of the pilot pressure oil from one pilot valve 18E to the pilot chamber 12E is cut off, the pilot chamber
Valve path from 12E to second pilot valve 19 is opened
State and was supplied to the pilot chamber 12E.
The pilot pressurized oil returns to the oil tank 17,
As a result, the main valve 12 returns to the stop position. In this state, shall apply only extension by manual operation of the hydraulic cylinder 11 is inhibited, reduced manual actuation operation is maintained to remain acceptable. Incidentally, the switching operation of the third pilot valves 20E, 20R from the first position to the second position can be either instantaneous switching or gradually switching, and instantaneous when the former is adopted. When the latter is adopted, the return of the main valve 12 to the stop position is gradually performed with a certain period of time.
Will gradually slow down and stop. In this case, based on the detection value from the stroke sensor 22, the vehicle is decelerated with a margin from a position slightly before reaching a preset expansion / contraction limit value (it is more convenient if the position can be set freely). It is also possible to calculate the deceleration start point position, decelerate from the deceleration start point position, and stop at the expansion / contraction limit value. In such a case, it is possible to stop smoothly without impact.

[0020] In this way, in the understood that the present invention has been carried out, and the automatic control and manual control of the actuator it
When the hydraulic cylinder 11 is in the expansion / contraction operation limit state during manual control, the supply of hydraulic oil to the hydraulic cylinder 11 is automatically stopped, and the operation limit state is established. Hydraulic cylinder 11
On the other hand, it is possible to avoid a problem that the supply of the pressure oil toward the operation limit side is continued.

In addition, the third pilot valves 20E and 20R, which are switched to stop the supply of the pilot pressure oil in the manual control state, switch the second pilot valve 19 from the pilot pump 16 when performing the automatic control of the actuator. This is a pilot valve that is absolutely necessary to supply the passed pilot pressure oil to either the expansion-side pilot chamber 12E or the reduction-side pilot chamber 12R. Therefore, it is necessary to automatically control the actuator. 3rd pilot valve 20E, 20R
As a result, the pilot pressure oil supply can be stopped when the actuator reaches the limit position during manual operation by effectively using the automatic control pilot valve means. There is no need to separately provide a valve means in the pilot oil passage for manual control, so that the members can be shared and the structure can be simplified. Moreover, priority stoppage during manual control
The execution of the stop is performed by the pilot chamber 12E of the main valve 12,
It is performed by returning the pilot pressure oil of 12R.
The first stop is naturally performed. In addition,
Dynamic control and priority stop during manual control.
And a pair of pilot chambers 12E, 1
For supplying and discharging pilot pressurized oil to 2R
The oil passage from the third pilot valves 20E and 20R
Are combined into one and provided in this one combined oil passage
Performed by switching one second pilot valve 19
The second pilot valve 19
And a pair corresponding to the pilot chambers 12E and 12R.
There is no need to provide them, and the number of parts can be reduced.
You.

The present invention is, of course, not limited to the above-described embodiment, and as in the second embodiment shown in FIG. 6, the oil from the first pilot valves 18E, 18R to the third pilot valves 20E, 20R. The passage and the oil passage from the second pilot valve 19 to the third pilot valves 20E and 20R are joined at an intermediate point, and the shuttle valve 2 is connected to the junction.
The same method can be applied to those provided with 7E and 27R. In the above-described embodiment, the opening amount of the first pilot valves 18E and 18R can be directly adjusted by the operation amount of the manual operation tool 14. However, such opening amount adjustment can also be performed electrically. . In this case, the operation amount of the manual operation tool is detected by, for example, a potentiometer, and the pilot control unit 15 that has received the detection signal transmits the opening amount to the first pilot valves 18E and 18R in accordance with the detection signal. What is necessary is just to comprise so that the operation command to prepare may be output.

Further, the supply stop of the pilot pressure oil during the manual operation is performed not only when the hydraulic cylinder is in the operation limit state but also in a stage before reaching the operation limit.
For example, it can be set to be performed when an abnormal load is applied to the hydraulic cylinder or when an obstacle is detected.In this case, the hydraulic cylinder is provided with abnormality detecting means and obstacle detecting means, and The detection signal from these detection means may be input to the pilot control section, and the other steps can be similarly performed. Furthermore, as the control procedure of the pilot control unit is not limited to those shown in the flow chart diagrams, short, A
Selective control switching between automatic and manual control
If the actuator operation is detected during manual control, the pilot control
It is only necessary that a stop command is output in preference to the manual control using the lube means so that the stop during the manual control can be performed.

[0024]

[Advantageous effects] In short, since the present invention is configured as narrative, in which the automatic control and manual control of the actuator can be selected respectively, manually system
If the actuator stop is detected during operation,
Manual control of the third pilot valve based on the detection
Switch from the first position in the state to the second position in the automatic control execution state
The first pilot valve for manual control
Of the pilot pressure oil supplied to the main valve from
While the supply was cut off, the power supplied to the main valve was
Illot pressure oil is supplied to the third pilot valve and the second pilot valve.
Return to the oil tank via the
The in-valve switches to the neutral position,
The eta is given a natural priority stop, and the actuator
And the supply of pressurized oil continues.
Can be avoided. Moreover, in the present invention, the second
If the second and third pilot valves are
This allows the components to be used together, reducing the number of parts.
In this case, the second pilot valve
Joins the oil passages from the pair of third pilot valves
Because provided so as to connect to the merging oil passage has a main bar
There is only one pilot room for Lube
Therefore, there is no need to provide a pair.
The points can be further reduced , and the structure can be simplified.

[Brief description of the drawings]

FIG. 1 is a schematic side view of a hydraulic shovel.

FIG. 2 is a flowchart showing a control procedure.

FIG. 3 is a hydraulic circuit diagram of the valve control device in a manual control state.

FIG. 4 is a hydraulic circuit diagram when a priority stop command is output during manual operation on the extension side.

FIG. 5 is a hydraulic circuit diagram of the valve control device in an automatic control state.

FIG. 6 is a hydraulic circuit diagram of the valve control device in a manual control state according to the second embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 11 hydraulic cylinder 12 main valve 12E extension-side pilot chamber 12R reduction- side pilot chamber 15 pilot control unit 16 pilot pump 17 oil tank 18E extension-side first pilot valve 18R reduction- side first pilot valve 19 second pilot valve 20E extension-side third Pilot valve 20R Reduction third pilot valve 22 Stroke sensor

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-194103 (JP, A) JP-A-62-151603 (JP, A) JP-A-54-34893 (JP, U) 22070 (JP, B2) (58) Field surveyed (Int. Cl. ⁷ , DB name) F15B 11/08 F15B 20/00 E02F 9/22

Claims (1)

(57) [Claims] 1. A pilot oil passage for the main valve switching to the switching of pressure oil supplied to the actuator, activator
One of the main valves provided for manual control of the writer
It is provided corresponding to the pilot room of the pair,
A pair of first valves with alternate valve switching based on the operation
Automatic control of pilot valves and actuators
Automatic start with no manual operation
Pilot control section output when switch is turned ON
Automatic control system set in advance based on control commands from
Pilot in the pilot chamber of the main valve based on the
Pilot valve means for automatic control to supply pressurized oil
Manual-automatic control of actuator
For hydraulic actuators
In the valve control device, a manual
Operation stop state where the actuator is set in advance during control
More actuators in response to the detection of
Pilot oil passage of main valve to stop supply of pressurized oil
In the configuration for switching the automatic control, the automatic control
The pilot valve means is installed in the pilot chamber of the main valve.
A corresponding pair is provided, and a manual
The automatic control pilot oil passage closes
The first that can open the pilot oil passage for dynamic control and perform manual control
Pilot oil for manual control in response to position and automatic control commands
The channel is closed and the pilot oil passage for automatic control is opened for automatic control.
The valve is switched so that it can be executed to the second position.
The third pilot valve and the third pilot valve
Joined the oil passage on the inlet side of pilot pressure oil for automatic control of
Connected to the junction oil passage and manually controlled by the pilot control unit
First place to connect the merging oil passage to the oil tank side in response to a command
Pie for automatic control
Valve switching to the second position to supply lot pressure oil
With the second pilot valve
In addition, the pilot control unit includes the above-mentioned manual control state.
And a third pie corresponding to the detection of the operation stop state.
Valve switching from first position to second position for lot valve
Priority stop during manual control to output manual command and stop manual control
A valve control device for a hydraulic actuator, comprising a stopping means .