JPS5941537A - Control on oil pressure of excavator - Google Patents

Abstract

PURPOSE:To permit smooth excavation by an excavator by a method in which when an excavator is in operation, a vibration signal is given to a proportional control valve provided to intermittently change the speeds of a cylinder. CONSTITUTION:When a solenoid valve 14 is in non-excited state, the valve 14 is held at the position as shown by Fig., and one pilot pathway 12 is led through a communication path 19 to a proportional control valve 15 and the other pilot pathway 13 is led to an tank 20. When the valve 14 is excited, the pilot pathway 13, on the contrary, is led to the proportional control valve 15 and the pilot pathway 12 is led to the tank 20. When a manual switch 47 is closed, the solenoid valve can be continuously switched only during the period when the switch 47 is closed. Thereafter, smooth excavation can be attained when the excavator of a bucket and the like is vibrated.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control method for reducing excavation resistance of a power shovel or the like by applying minute vibrations to a barrack or the like during excavation.

(Conventional Control Method) The conventional control circuit shown in FIG. A protrusion 5 for stroke detection is provided at the protrusion 5 for stroke detection.

A micro-switching valve 6 is located within the locus of movement of the protrusion 5.
．． 7 and this micro switching valve 6.7
is switched when the protrusion 5 abuts, and the pressure oil of the pump 8 is applied to the excitation/help 2 to vibrate the cylinder 3, that is, the packet, etc.

In the conventional circuit type as described above, when the cylinder 3 reaches a certain specific stroke, the cylinder 3 is automatically overconfident.

In other words, the stroke position at which the packet or the like is to be vibrated is always specified, making it impossible to vibrate the packet at an arbitrary position.

Moreover, the above-mentioned vibration valve 2 and micro switching valve 6
．． There were also problems with its economic efficiency, such as requiring 7.

(Objective of the Invention) The object of the present invention is to provide a hydraulic control method that excites an excavating part such as a bucket at an arbitrary stroke position and does not require an excitation valve or a micro-switching valve.

(Embodiment of the present invention) The drawings show an embodiment of a power shovel, and the first embodiment shown in FIGS. 2 to 4 includes a cylinder 10 that drives a packet, and a directional control valve 11 that controls this cylinder. and a two-position solenoid valve 14 for selecting one of the pilot passages 12 and 13 for this directional control valve 11;
A proportional control valve 15 provided upstream of the solenoid valve 14 is provided.

In the illustrated neutral position, the directional control valve 11 returns oil from the pump 16 directly to the tank 18 via the neutral passage 17. The cylinder 10 is extended when it is bent to the left side position shown in the figure, and is contracted when it is switched to the right side position.

The solenoid valve 14 is held at the position shown in the figure when in a non-energized state, and communicates one pilot passage 12 with the proportional control valve 15 via a communication passage 19, and connects the other pilot passage 13 with the tank. Connect to 20. When the solenoid valve 14 is energized, the other pilot passage 13 communicates with the proportional control valve, and one pilot passage 12 communicates with the tank 20.

Furthermore, the proportional control valve 15 is driven in proportion to an electric signal to be described later, but in the illustrated state, the communication path 1
8 is communicated with the tank 21, while the auxiliary pump 22 and the communication passage 18 are communicated with each other when switched in response to the above signal.

Therefore, by controlling the solenoid valve on and off, the directional control valve 11 is switched to either the left or right, and the cylinder 10 is expanded or contracted.

Further, the opening degree of the proportional control valve 15 is determined according to the electric signal, and the pilot pressure from the auxiliary pump 22 is adjusted according to the opening degree. And this proportional control valve 15
The opening degree of the directional control valve 11 is determined in accordance with the pilot pressure determined by the directional control valve 11, and the flow rate supplied to the cylinder IO can be adjusted, so that its speed can be controlled.

The electric circuit described below controls the hydraulic circuit as described above.

That is, when the operator directly operates the input section 23, a speed signal and a direction signal are transmitted simultaneously.

The speed signal is then directly input to the proportional control valve 15, and the proportional control valve 15 is controlled according to the speed signal.

Further, when the operator operates the input unit 23 as described above, the direction signal is inputted to the direction control circuit 24, but if the manual switch 25 is open at this time, the first gate circuit 26 is opened, and the direction signal is inputted to the direction control circuit 24. The signal is input via the first OR circuit 27 to a drive circuit 28 that drives the solenoid valve 14 .

On the other hand, when the manual switch 25 is closed, the signal is inverted by the inverting circuit 28 and input to the first gate circuit 28, and the first gate circuit 26 is closed. Therefore, the direction signal from the direction control circuit 24 is not output from the first OR circuit 27.

Further, as described above, when the manual switch 25 is closed, the second gate circuit 30 opens, and either the excavation vibration signal or the supernatant vibration No. 4i'r is input to this second gate circuit 30. Become.

In other words, the excavation vibration transmitter 3 constantly transmits excavation signals.
1 and a supernatant vibration transmitter 3 that constantly transmits supernatant signals.
2 are connected to a second OR circuit 35 via a third gate circuit 33 or a fourth gate circuit 34, and this second OFF circuit 35 is connected to the second gate circuit 30.

And the third gate circuit 33 and the fourth gate circuit 34
opens and closes in response to an extension signal or a contraction signal output from the direction control circuit 24.

When a contraction signal is output from the direction control circuit 24, the signal is input to the fourth gate circuit 34 to open the fourth gate circuit 34, while the contraction signal is passed through the inversion circuit 36 to the third gate. Since it is input to the circuit 33, the third
The gate circuit 33 remains closed.

Therefore, the supernatant signal output from the supernatant vibration oscillator 32 is transmitted from the fourth gate circuit 34 to the second OR circuit 35 to the second
The signal is input to the drive circuit 28 via the gate circuit 30 and the first OR circuit 27.

When the supernatant signal is input to the drive circuit 28 as described above, the solenoid valve 14 responds to the supernatant signal.
is controlled on and off, and the directional control valve 11 is reciprocated in a short period of time.

If the directional control valve 11 reciprocates in a short time, the cylinder 1
In other words, the packet can vibrate and remove soil attached to it.

Further, when an extension signal is output from the direction control circuit 24, the signal is directly input to the fourth gate circuit 34, but at this time, the fourth gate circuit 34 is closed.

The extension signal is input to the third gate circuit 33 via the inversion circuit 36, and the third gate circuit 33 is opened.

When the third gate circuit 33 is opened as described above, the excavation signal output from the excavation vibration transmitter 31 is transmitted to the second OR circuit 33.
→ second gate circuit 30 → input to the drive circuit 28 via first OR circuit 27.

Therefore, the solenoid valve 14 is controlled on and off in response to the excavation signal, causing the directional control valve 11 to reciprocate.

As described above, the reciprocating operation of the directional control valve 11 is exactly the same in both cases of excavation control and supernatant control.

However, in the case of the above-mentioned excavation control, it is necessary to dig while reciprocating the packet, and in the case of supernatant control, the packet must be reciprocated at the same position. The frequency and duty of the excavation signal and supercleaning signal must be different.

For this purpose, the excavation signal transmitter 3 is used as a signal generation source of different quality.
1 and a supernatant signal transmitter 32, which can be selected as appropriate.

In other words, when the manual switch 25 is closed in the same way,
When the direction signal from the direction control circuit 24 is an extension signal,
The relationship is such that an excavation signal is output, and when the direction signal is a contraction signal, a supernatant signal is output.

FIG. 3 shows the relationship between the above elongation signal and the displacement of the cylinder lO.

As is clear from FIG. 3, when the direction control circuit 24 is outputting the extension signal, the manual switch 25
When it is closed, an excavation signal is output from the first OR circuit 27, and during this time the cylinder 10 is extending while reciprocating.

FIG. 4 shows the relationship between the contraction signal and the displacement of the cylinder lO.

Also in FIG. 4, when the manual switch 25 is closed while the contraction signal is being output from the direction control circuit 24, the supernatant signal is output, and during this time the cylinder 10 reciprocates at a fixed position. It is clear that there are.

In the second embodiment shown in FIGS. 5 and 6, the solenoid valve 37 is set to three positions and opened at the center, and the other points of the hydraulic circuit are the same as the first embodiment.

Therefore, in this second embodiment, the cylinder 10, that is, the packet, cannot be reciprocated unless the extension side and the contraction side of the solenoid valve 37 are controlled on and off. A control circuit is required.

To explain the above control circuit, the signals 1'i from the input section 38 directly inputted by the operator are a direction signal and a speed signal, as in the first embodiment.

The speed signal is directly input to the proportional control valve 39, and the proportional control valve j39 is controlled according to the speed signal.

Further, the direction signal is input to the direction control circuit 40, and the extension signal is sent from the first gate circuit 41 via the first OR circuit 42 to turn on and off the extension side solenoid of the solenoid valve 37. 1 is input to the drive circuit 43, and the solenoid on the extension side thereof is energized.

Further, when the signal output from the direction control circuit 40 is a contraction signal, the contraction signal is passed from the second gate circuit 44 to the second OR circuit 45.
The signal is input to a second drive circuit 46 that controls on/off the solenoid on the contraction side, and energizes the solenoid on the contraction side.

However, when the manual switch 47 is closed, the signal from the manual switch is inputted to both gate circuits via the inverting circuit 48, 48, and the gate circuits 41, 44 are closed.

Therefore, as long as this manual switch 47 is closed,
Neither the expansion signal nor the contraction signal is input to each drive circuit 43, 46.

Then, when the manual switch 47 is closed, an output signal from the excavation vibration transmitter 50 that constantly transmits the excavation signal or the supernatant vibration transmitter 51 that always transmits the supernatant signal is output from the first drive circuit 43. Alternatively, it will be input to the second drive circuit 46.

That is, the excavation vibration transmitter 50 is connected to the third gate circuit 52.
The supernatant vibration oscillator 51 is connected to the third OR circuit 53 via a fourth gate circuit 54.

The third gate circuit 52 opens only when the extension signal from the direction control circuit 40 is input and the manual switch 47 is closed, and the fourth gate circuit 54 opens when the contraction signal from the direction control circuit 40 is input. It is configured to open only when an input is made and the manual switch 47 is closed.

Therefore, depending on whether the signal is an expansion signal or a contraction signal, the signal from either one of the oscillators is the force t output from the third OR circuit 53, and the output signal is sent to the fifth gate circuit 55 and the sixth gate circuit 58. is input. However, the fifth gate circuit 5
Since an inverting circuit 57 is provided in the step 5, this 5th step
The output signal from the gate circuit 55 is inverted from the output signal from the sixth gate circuit 58.

Since the fifth and sixth gate circuits 55 and 56 are configured to open only when the manual switch 47 is closed, as long as the manual switch 47 is closed, the output signal from the third OR circuit 53 is is input to the first drive circuit 43 and the second drive circuit 4B.

FIG. 6 shows the mutual relationship when the extension signal is output from the direction control circuit 38.

As is clear from FIG. 6, when the manual switch 47 is closed while the elongation signal is being output, the excavation signal from the excavation vibration transmitter 50 is transmitted to the third orifice only during the closed period. The signal is output from the circuit 53.

Since the signals output from the fifth gate circuit 55 and the sixth gate circuit 56 are inverted, the first OR circuit 4
2 and the second OR circuit 45 also output inverted signals.

Therefore, the solenoid on the extension side and the solenoid on the contraction side are alternately turned on and off, causing the directional control valve 11 to reciprocate.

As a result, the packet performs an excavation operation while reciprocating.

Further, when the shrinkage signal is output from the direction control circuit 40, the supernatant signal from the supernatant vibration transmitter 51 is output from the first.
The above-mentioned supernatant signal is output from the 2-OR circuit 42.45, but the above-mentioned supernatant signal in this case is transmitted in the same manner as during excavation, except that its frequency and duty are different from the above-mentioned excavation signal. be done.

Each of the embodiments described above is characterized in that the excavation part such as the packet is vibrated by controlling a solenoid valve, and the electrical control circuit thereof is not limited to the embodiments described above.

For example, instead of an electrical control circuit as in the above embodiment,
Of course, a microcomputer may also be used.

(Configuration of the Present Invention) The configuration of the present invention includes a cylinder that drives an excavation unit such as a packet, a directional control valve that is switched by pilot pressure to expand and contract the cylinder, and a solenoid that selects a pilot passage for the directional control valve. In an excavator equipped with a valve and a proportional control valve that supplies or prevents the supply of pilot pressure from an auxiliary pump to this solenoid valve, by closing a manual switch,
The present invention is characterized in that the solenoid valve is continuously switched only during the time period when the manual switch is closed.

With the above configuration, if the manual switch is closed as necessary, the excavated portion of the packet or the like will automatically vibrate.

(Effects of the present invention) Since the excavation part such as the packet can be vibrated as necessary, for example, when excavation resistance is large and excavation cannot be performed, by vibrating the excavation part, smooth excavation can be achieved. becomes possible.

Also, when removing soil adhering to the excavated portion, the excavated portion can be vibrated, making it easier to clean the soil.

Moreover, in order to carry out the above-mentioned work, there is no need for a conventional vibration valve, and furthermore, by closing a manual switch at an arbitrary position, the digging part such as a packet can be vibrated at that arbitrary position.

[Brief explanation of the drawing]

Figure 1 is a conventional hydraulic circuit diagram, Figures 2 and 4 show the first embodiment of the present invention, Figure 2 is a circuit diagram, and Figure 3 shows signals and cylinder displacement during excavation. A diagram showing the relationship between
FIG. 4 is a diagram showing the relationship between each signal and the displacement of the cylinder during upward drop, and FIGS. 5 and 6 similarly show the second embodiment.
FIG. 5 is a circuit diagram, and FIG. 6 is a diagram showing the relationship between each signal during excavation and the displacement of the cylinder. 10...Cylinder, 11-φ・directional control valve, 12.1
3-ψ-pilot ij&, 14.37・---Solenoid valve, 22--@auxiliary pump, 25.47...
manual switch. Representative Patent Attorney Nobuyuki Shima

Claims (1)

[Claims] A cylinder that drives an excavating part such as a hecket, a directional control valve that is switched by pilot pressure and expands and contracts the cylinder, a solenoid valve that selects a pilot passage for this directional control valve, and a solenoid valve that is connected to an auxiliary pump. In an excavator equipped with a proportional control valve that supplies pilot pressure or blocks its supply, by closing a manual switch, the solenoid valve is continuously switched only during the time period when the manual switch is closed. Excavator hydraulic control method.