JPH0470481B2 - - Google Patents

Description

[Detailed description of the invention] Industrial applications The present invention relates to a control device for hydraulic equipment.

2. Description of the Related Art For example, a vehicle equipped with hydraulic equipment such as a hydraulically controlled crane is equipped with a remote control device so that the hydraulic equipment can be operated even at a location away from the vehicle. In this type of remote control device, a pilot piston for driving the directional switching valve is disposed in a directional switching valve that controls hydraulic oil introduced into the operating section of the base machine. Multiple solenoid valves installed in the oil path to the pilot piston are then selectively opened and closed using a switch installed in the remote control box, allowing hydraulic equipment such as a crane to be operated remotely from the vehicle. When the directional control valve is operated manually, all the solenoid valves are deenergized and the pilot piston is placed in the neutral position using a switch in the remote control box. This allows the pilot piston to move freely (see, for example, Japanese Patent Laid-Open No. 57-9306).

Problems to be Solved by the Invention However, in the conventional hydraulic equipment control device described above, when switching from the remote control state to the manual control state, it is difficult to position the pilot piston at the neutral position by operating a switch on the remote control box. When the remote control box outputs a signal to position the pilot piston to the neutral position, all solenoid valves are deenergized, and the pilot piston receives a predetermined spring force and is positioned at the neutral position. ing. Therefore, when the outside temperature is low and the viscosity of the hydraulic oil and lubricating oil in each part is high, the pilot piston will operate slowly due to the spring force alone, and the directional control valve will not follow the operating side. A problem arises in that it is not possible to quickly move to the neutral position. For this reason, there is a risk that the mother machine may perform an operation that is not intended by the operator, and there is also a problem with safety.

Therefore, an object of the present invention is to provide a control device for hydraulic equipment that enables remote control using a pilot cylinder and a switching valve, in which a signal is output for positioning the pilot cylinder in a neutral position to enable manual operation. If this happens, quickly move the pilot cylinder to the neutral position,
An object of the present invention is to provide a control device for hydraulic equipment that can quickly and safely switch from remote control to manual control.

Means for Solving the Problems The configuration of the present invention includes a directional switching valve for switching the direction of hydraulic pressure supplied to a hydraulic circuit of a hydraulic device;
A pilot piston connected to the directional switching valve for controlling the directional switching valve, a detection means for detecting the position of the pilot piston and outputting a position signal indicating the position, and a setting member for remote control. a position setting means for outputting an instruction signal for instructing a set position of the pilot piston; a control means for positioning the pilot piston according to a deviation between the position signal and the instruction signal; in response to an instruction signal, the instruction signal commands to position the pilot piston at a neutral position;
As a result, when the deviation between the position signal and the instruction signal falls within a predetermined range, the control operation by the control means is stopped and the pilot piston is allowed to move freely thereafter; and a second means for canceling the stoppage of the control operation of the control means by the first means in response to a command to position the pilot piston at a position other than the neutral position. .

Function In this hydraulic equipment control device, in order to allow the pilot piston to move freely and to manually operate the directional control valve, when the pilot piston is positioned at the neutral position by the position setting means, first In response to this, the control means quickly moves the pilot piston to the neutral position by hydraulic pressure, so that when the deviation between the position signal and the instruction signal falls within a predetermined range, the first means is actuated. The restraining force exerted on the pilot piston by the control means is now removed, and the directional control valve can now be operated manually. In this way, once the switching from remote control to manual control has been carried out, even if the pilot piston is moved by manual operation and the deviation between the position signal and the instruction signal becomes large again, the first means will not work. Therefore, the control means does not control the position of the pilot piston. The state in which the operation of the control means is stopped by the first means is canceled by the second means in response to the setting position of the pilot piston being set to a position other than the neutral position by operation of the position setting means.

EXAMPLES Hereinafter, the present invention will be explained in detail with reference to illustrated examples.

FIG. 1 shows a hydraulic equipment control device 20 according to the present invention.
A system diagram of hydraulic equipment controlled by is shown. The pressure control valve 1 is used to maintain a constant pressure in the oil passage 4 of hydraulic oil sucked up from the tank 3 by the oil feed pump 2.
The pressure-adjusted hydraulic oil is supplied to a hydraulic system (not shown) of a mother machine 19 such as a crane, for example, through an oil passage 4 and a directional control valve 6 connected to a manual operation lever 5. The return oil passage 7 communicates the mother machine 19 and the tank 3 via the directional switching valve 6. The hydraulic oil passage 4 communicates with a pilot oil passage 10 via a check valve 8 and a pressure reducing valve 9, and the pressure of the pilot oil passage 10 is controlled by a pressure control valve 11. Three solenoid valves 12, 13, and 14 arranged in series are connected to the pilot oil passage 10 whose pressure is set by the pressure control valve 11. A pilot piston 15 is connected to the directional control valve 6, and the directional control valve 6 and the pilot piston 15 are moved together by the manual lever 5. One chamber 16 of the pilot piston 15 is connected to the oil passage between the normally closed solenoid valve 12 and the normally open solenoid valve 13, and the other chamber 17 is connected to the oil passage between the normally open solenoid valves 13 and 14. is connected to. Also,
The pressure receiving area of the chamber 17 is larger than the pressure receiving area of the chamber 16, for example, about twice as large. The normally closed solenoid valve 12 is switched to the open position when the solenoid 12S is energized, and the normally open solenoid valves 13 and 14 are switched to the closed position when the solenoids 13S and 14S are energized, respectively. When solenoid valve 12 is on, solenoid valve 1
When chambers 3 and 14 are off, chambers 16 and 14 are turned off, respectively.
17 are communicated with each other via the electromagnetic valve 13, the piston 15 can move freely, and therefore the directional control valve 6 can be freely switched and controlled by the manual operation lever 5. Solenoid valve 12 is off, solenoid valve 1
When both solenoid valves 3 and 14 are turned on, each of these solenoid valves 12, 13, and 14 closes the pilot oil passage 10, so that the pilot piston 15 is fixed at that position. Further, in this state, the manual operation lever 5 cannot be used to switch the directional control valve 6. When the solenoid valves 12 and 13 are on and the solenoid valve 14 is off, the hydraulic oil in the pilot oil passage 10 flows into the chamber 16 of the pilot piston 15, while the hydraulic oil in the chamber 17 returns to the tank 3, so that the pilot The piston 15 moves to the left (in the direction of arrow A), and moves the directional control valve 6 to the left to switch to position 6A. Also, the solenoid valves 12 and 14 are turned on and 13
When OFF, both the hydraulic oil in the pilot oil passage 10 flows into the chambers 16 and 17. however,
As mentioned above, since the pressure receiving area of the chamber 17 is larger than the pressure receiving area of the chamber 16, the piston 15 moves to the right (in the direction of arrow A'), and the directional control valve 6 moves to the right. and switch to position 6B. Further, a position detector 18 is attached to one end side 15a of the pilot piston 15.
The displacement of the pilot piston 15 is detected. This position detector 18 is constructed using, for example, a potentiometer, and outputs a position signal V _F whose level changes in accordance with the displacement of the pilot piston 15. The level of this position signal V _F varies depending on the movement of the pilot piston 15. For example, when the pilot piston 15 is in the center position, the level is 12V, the more it moves to the left, the higher it becomes, and the more it moves to the right, the lower it becomes. It is set so that a voltage is generated depending on the position of the

The hydraulic equipment control device 20 includes a position setting device 2 including an operating lever 21 for the purpose of outputting an instruction signal V _IN indicating the set position of the pilot piston 15.
2, and a control unit that operates in response to the position signal V _F and the instruction signal V _IN and controls the opening and closing of the solenoid valves 12 to 14 in order to position the pilot piston 15 at the position indicated by the instruction signal _{V IN.} 3
0, the position signal V _F and the instruction signal V _IN , and the switching for controlling the switching between the remote control mode by the control unit 30 and the manual control mode by the manual operation lever 5 in accordance with the instruction signal V _IN . It consists of a control unit 40.

The position setting device 22 is composed of, for example, a potentiometer, and outputs an instruction signal according to the position of the operating lever 21.
Output V _IN . The clockwise (arrow C direction) and counterclockwise (arrow CC direction) movements of the operating lever 21 are set so as to correspond to the leftward and rightward movements of the directional control valve 6. The position setting device 22 instruction signal V _IN is, for example, 4V when the operating lever 21 is rotated clockwise to the maximum position, 12V when it is in the neutral position, and 20V when it is rotated counterclockwise to the maximum position. In between, it is set to change depending on the rotational position.

FIG. 2 shows a circuit diagram of the hydraulic equipment control device 20. As shown in FIG. Here, the control unit 30 is a circuit unit for performing feedback control using the position signal V _F so that the pilot piston 15 is positioned at the position indicated by the instruction signal V _IN . Control signal based on the control calculation result performed in 30
V _a , V _b , and V _d are output. Control signals V _a , V _b ,
V _d is for solenoids 14S, 13S and 1, respectively.
2S, thereby controlling the position of the pilot piston 15 and controlling the directional control valve 6 to a desired state. The pilot piston 1 responds to the position signal V _F and the instruction signal V _IN .
5, that is, the circuit configuration for performing feedback control to position the directional control valve 6 at a desired position is well known, so detailed illustration of the circuit configuration of the control unit 30 is omitted in this specification.

Next, to explain the switching control unit 40, R ₁ to R ₂₄ are resistors, Q ₁ to Q ₆ are transistors, D ₁ to D ₄ are diodes, and C ₁ to C ₄ are voltage comparators whose outputs are open collector type. It is a vessel. terminal 4
1 is connected to the positive electrode of a battery (not shown),
Its terminal voltage U _B is given. A circuit voltage _Vcc obtained by stabilizing the battery voltage with a voltage stabilization circuit (not shown) is applied to the terminal 42, and the terminals 43 and 44
A position signal V _F and an instruction signal V _IN are respectively applied to. Voltage comparators C ₁ and C ₂ constitute a window comparator circuit 45 for detecting whether the level of the instruction signal V _IN is within the range of V ₁ >V _IN >V ₂ . The values of voltages V ₁ , V ₂ are determined by resistors R ₁ ,
By adjusting the values of R ₂ and R ₃ , the window comparator circuit 45 determines whether the level of the instruction signal V _IN has reached the predetermined level L ₀ for instructing the pilot piston 15 to be positioned in the neutral position. is set to a value that allows detection with the required accuracy. Therefore, only when V ₁ >V _IN >V ₂ , the level of the voltage V ₃ at the connection point between the outputs of the voltage comparators C ₁ and C ₂ becomes "H".

The voltage comparators C ₃ and C ₄ also constitute a window comparator circuit 46, and this window comparator circuit 46 is adapted to discriminate the level of the position signal _VF . The reference voltages for level discrimination in the window comparator circuit 46 are the voltage V 4 at the non-inverting input terminal of the voltage comparator C _{3 and} the voltage V ₅ at the inverting input terminal of the voltage comparator C ₄ , where V ₄ > V _F
> _V5 , the potential at the connection point of each output of the voltage comparators _C3 and _C4 becomes "H" level.

A resistor is connected to the inverting input terminal of voltage comparator _C4 .
A transistor to which a voltage dividing circuit 47 consisting of R ₁₁ and R ₁₂ is connected and whose emitter is grounded
The collector of Q ₃ is connected via a resistor R ₁₃ , and the level of voltage V ₅ matches the output level L ₅ of the voltage divider 47 when transistor Q ₃ is off, and when transistor Q ₃ When it is on, it becomes approximately earth level.

On the other hand, the non-inverting input terminal of voltage comparator _C3 has
A voltage divider circuit 48 consisting of resistors R ₉ and R ₁₀ is connected, and the collector of a transistor Q ₄ whose emitter is connected to the terminal 42 is connected via a resistor R ₁₄ and whose emitter is grounded. The collector of transistor _Q2 is connected. Therefore, the level of voltage V ₄ is the same as that of transistors Q ₂ and Q ₄
When both are off, it matches the output level L ₄ of the voltage divider circuit 48, when only transistor Q ₂ is on, it is approximately ground level, and on the other hand, when only transistor Q ₄ is on, it is approximately V It will be equal to the level of _cc .

Transistor Q ₂ has voltage V ₃ at “L” level.
Therefore, when transistor Q ₁ is turned off, it is turned on. Transistor Q ₃ is turned on when the output voltage V ₆ of the window comparator circuit 46 becomes "H" level, and transistor Q ₄ is also turned on when the output voltage V ₆ becomes "H" level, transistor Q ₅ is turned on. It turns on when

Next, the operation of the switching control unit 40 shown in FIG. 2 will be explained.

Since the remote control operation is executed using the lever 21, the level of the instruction signal V _IN is set to V _IN
>V _I or V _IN <V ₂ , the level of the output voltage V ₃ of the window comparator circuit 45 is “L”.
Therefore, transistor Q ₁ is off and transistor Q ₂ is on. As a result, the level of voltage V ₄ becomes approximately equal to ground level.
By the way, the level of the position signal V _F is set such that it changes between a value approximately 1 to 2 V higher than the ground potential and a value approximately 1 to 2 V lower than the power supply voltage V _cc in the normal operating range of the pilot piston 15.
A position detector 18 is designed. Therefore, when the transistor Q ₂ is on, V _F >V ₄ is sure to hold, so the output level of the voltage comparator C ₃ is "L", and the level of the output voltage V ₆ is also "L". ”. Therefore, since transistor Q ₅ is off, transistor Q ₆ is also off,
The anodes of diodes D ₃ and D ₄ connected to the collector of transistor Q ₆ are at ground level. The cathodes of these diodes D ₃ and D ₄ are
Output transistors provided in the control unit 30 corresponding to each solenoid 14S, 13S
It is connected to the bases of Q ₇ and Q ₈ , and therefore does not interfere with the operation of each output transistor Q ₇ and Q ₈ when transistor Q ₆ is off. However, the solenoids 12S to 14S of the solenoid valves 12 to 14 operate according to the calculation results of the control unit 30, and the positioning operation of the pilot piston 15 in accordance with the operation of the lever 21 is controlled by feedback as described above. will be done.

The position of the pilot piston 15 is set to the neutral position, thereby switching to manual operation using the manual operation lever 5. When the lever 12 is operated so that the level of V _IN becomes _L0 , first, the window comparator circuit 45 turns off transistor _Q2 in response. In this state,
The level of the output voltage V ₆ is "L", and the transistors Q ₃ , Q ₄ , and Q ₆ are all off.
Therefore, the level of voltages V ₄ and V ₅ is determined by each voltage dividing circuit 4.
They are levels L ₄ and L ₅ defined by 8 and 47. By the way, levels L ₄ and L ₅ are voltages V ₁ and
Therefore, even if the level of the instruction signal V _IN becomes L ₀ , the output voltage V ₆ will be equal to the level of V ₂ unless V ₄ > V _F > V ₅ .
The level remains at "L".

Therefore, even if the level of the instruction signal V _IN reaches _L0 , the position of the pilot piston 15 remains unchanged from the control unit until the position detector 18 detects that the position of the pilot piston 15 has reached the neutral position. 30, feedback control is performed so that V _IN =V _F. In this way, V ₄ >
When V _F > V ₅ , the level of output voltage V ₆ becomes “H”
As a result, transistor Q ₆ turns on, locking output transistors Q ₇ and Q ₈ in the off state. As a result, the solenoid valve 12 is controlled on and off by the control unit 30, the solenoid valves 13 and 14 are respectively turned off, the pilot piston 15 is free to operate, and the manual operation lever 5 can no longer manually operate the directional valve 6. becomes possible.

When the level of the output voltage V ₆ becomes "H", the transistors Q ₃ and Q ₄ are also turned on, and the voltage V ₄ becomes approximately equal to the power supply voltage V _cc , while the voltage V ₅ becomes equal to the ground potential. As a result, even if the level of the position signal V _F from the position detector 18 changes by manually operating the directional control valve 6, the position signal
The level of V _F does not fall outside the level range determined by the voltages V ₄ and V ₅ at this time, and the level of the output voltage V ₆ of the window comparator circuit 46 remains "H" during the manual control mode described above. held at the level.

That is, in response to the level of the instruction signal V _IN becoming _L0 , the control unit 30 returns the position of the pilot piston 15 to the neutral position until V _IN =V _F , and V _IN =V _F. If it is determined that this is the case, the positioning operation of the pilot piston 15 by the control unit 30 is stopped, and thereafter the directional control valve 6 is maintained in a state where it can be freely positioned manually. Therefore, compared to conventional devices in which the control unit immediately stops operating when the level of the instruction signal V _IN reaches L ₀ and the pilot piston 15 is placed in its neutral position by, for example, only spring force. The pilot piston 15 can be moved to the neutral position more quickly. As a result, switching from remote control mode to manual control mode is quickly performed. This is particularly effective in quickly performing the switching when the outside temperature is low and the oil viscosity is high and the hydraulic mechanism operates slowly. In this way, if the control mode is quickly switched regardless of the outside temperature,
During the switching, problems such as the mother machine performing undesired operations will not occur, and safety will be significantly improved.

In the manual control mode, the lever 21 is operated and the level L ₀ of the instruction signal V _IN changes, so that V _IN > V ₁
Or, when V _IN <V ₂ , the level of the output voltage V ₃ of the window comparator circuit 45 becomes "L",
Since transistor Q ₂ is turned on, the output voltage V ₆
becomes “L” again, and the transistors Q ₃ ,
Q ₄ and Q ₆ are all off. As a result, the control mode is switched to a remote control mode by operating the lever 21, and the solenoids 12S to 14S are driven based on signals from the control unit 30.

It should be noted that it will be easily understood from the description based on the above embodiments that the present invention can be widely applied to control devices for various hydraulic equipment including cranes.

Effects According to the present invention, as described above, when switching the control mode of hydraulic equipment from remote control mode to manual control mode, it is possible to realize extremely quick switching even when the outside temperature is low. This provides an excellent effect of effectively preventing runaway of the hydraulic equipment that tends to occur in the hydraulic equipment during the transition period of switching.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a hydraulic system equipped with a hydraulic equipment control device according to the present invention, and FIG. 2 is a circuit diagram of the hydraulic equipment control device shown in FIG. 5...Manual operation lever, 6...Directional switching valve, 12,
13, 14...Solenoid valve, 12S, 13S, 14S...
Solenoid, 15...Pilot piston, 18...
Position detector, 19... Mother machine, 20... Hydraulic equipment control device, 21... Operation lever, 22... Position setting device, 30
...Control unit, 40...Switching control unit.

Claims (1)

[Claims] 1. A directional switching valve for switching the direction of hydraulic pressure supplied to a hydraulic circuit of a hydraulic device, a pilot piston connected to the directional switching valve for controlling the directional switching valve, and detecting the position of the pilot piston. a detection means for outputting a position signal indicating the position; a position setting means for outputting an instruction signal for instructing the set position of the pilot piston in conjunction with a setting member for remote control; and the position signal and the instruction signal. control means for positioning the pilot piston according to the deviation from the pilot piston;
In response to the position signal and the instruction signal, the instruction signal commands the pilot piston to be positioned at a neutral position, and when the deviation between the position signal and the instruction signal falls within a predetermined range. a first means for stopping the control operation by the control means and thereafter freeing the movement of the pilot piston; A hydraulic equipment control device comprising: second means for canceling the stoppage of the control operation of the control means by the first means.