JP3027529B2 - Interference prevention equipment for construction machinery, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of an interference preventing device for a construction machine or the like.

[0002]

2. Description of the Related Art Conventional interference prevention devices used in construction machines such as hydraulic excavators include a system for controlling a change in the discharge amount of a hydraulic pump and a system for controlling a pilot pressure of a main switching valve of an actuator such as a cylinder. There is. The former is
For example, it is disclosed in Japanese Patent Laid-Open Publication No. Hei 3-156037. This control method has a higher efficiency of the hydraulic pump than the latter, but requires a hydraulic pump with a variable discharge rate,
It is inferior to the latter control method in that fine control cannot be performed. FIG. 5 schematically shows the entire configuration of the latter control method. FIG. 6 is a diagram showing a configuration of a control type device that detects a boom tilt angle, an arm tilt angle and an offset angle to prevent interference by using a conventional example.
Hereinafter, this conventional example will be described.

In FIG. 5, a hydraulic pump 1 and an oil tank 2
Are connected to the primary side of the main switching valve 3, and the secondary side of the main switching valve 3 is connected to both ports of the piston cylinder 4 by oil passages. The pilot ports of the main switching valve 3 are connected to remote control valves 7 of a remote control device 6 via proportional electromagnetic pressure reducing valves 5 and 5, respectively. The remote control valves 7 are operated by an operation lever 8. Pilot hydraulic pump 9
And an oil tank 10 are respectively connected to the primary sides of the remote control valves 7 and 7 as shown in the figure. The proportional electromagnetic pressure reducing valves 5, 5 are controlled as described below in a safety zone, a deceleration zone, and a stop zone of the working machine.

FIG. 6 shows a main switching valve 3 for controlling a boom cylinder.
1A shows a configuration of a conventional interference prevention device that controls a main switching valve 3b for controlling an arm cylinder and a main switching valve 3c for controlling an offset cylinder. The primary ports of the remote control valve 7a for controlling the boom cylinder, the remote control valve control 7b for controlling the arm cylinder, and the remote control valve 7c for controlling the offset cylinder are connected to the pilot hydraulic pump 9 and the oil tank 10. Each is connected. The secondary ports of the remote control valves 7a, 7b, 7c are connected to the primary ports of the proportional electromagnetic pressure reducing valves 5a, 5b, 5c by oil passages 11a, 11b, 11c, respectively.

The secondary ports of the proportional electromagnetic pressure reducing valves 5a, 5b and 5c are respectively connected to oil passages 12a, 12b and 12c to control a main switching valve 3a for controlling a boom cylinder, a main switching valve 3b for controlling an arm cylinder, and an offset cylinder control. Ports 13a, 13b, 1 of the main switching valve 3c for
3c. Primary ports of the main switching valve 3a for controlling the boom cylinder, the main switching valve 3b for controlling the arm cylinder, and the primary port of the main switching valve 3c for controlling the offset cylinder are connected to the hydraulic pump 1 and the oil tank 2,
The secondary ports are connected to ports of a boom cylinder, an arm cylinder, and an offset cylinder, respectively (see FIG. 5).

FIG. 7 shows the proportional electromagnetic pressure reducing valves 5a, 5b, 5c.
3 shows the characteristics of the command current I flowing through the solenoid and the secondary hydraulic pressure A. As is clear from this figure, the secondary hydraulic pressure A of the proportional electromagnetic pressure reducing valve increases in proportion to the command current I.
Therefore, when the maximum rated command current Imax flows through the solenoid, the proportional electromagnetic pressure reducing valve is almost fully opened, and the primary hydraulic pressure P appears as the secondary hydraulic pressure as it is. Conversely, when the command current flowing through the solenoid is set to zero, the secondary port of the proportional electromagnetic pressure reducing valve is completely connected to the tank T, and the secondary hydraulic pressure becomes zero.

The controller 16 for controlling the command current I flowing through the solenoids of the proportional electromagnetic pressure reducing valves 5a, 5b, 5c is configured as follows. That is, in FIG. 6, the output signals of the boom tilt angle detection sensor 15a, the arm tilt angle detection sensor 15b, and the offset angle detection sensor 15c provided in the work machine are output by an amplifier (not shown)
The data is taken into the controller 16 via the / D converter. The controller 16 calculates the position of the bucket from the data of the boom tilt angle, the arm tilt angle, and the offset angle, and the data of the rear boom length, the front boom length, the upper boom length, the arm length, and determines the current area of the bucket. Then, command currents Ia, Ib, and Ic are output.

The command currents Ia, Ib,
The output terminal of Ic is connected to the redundant switching relays 17a, 17b, 17
is connected to each of the solenoids of the proportional electromagnetic pressure reducing valves 5a, 5b, 5c. Redundancy changeover switches 17a, 17
When the abnormality of the controller 16 is detected, b and 17c are connected to the power supply directly to the solenoids of the proportional pressure reducing valves 5a, 5b and 5c so that the operation can be continued. When a redundancy switch button 18 provided at an appropriate position in the operator's cab is pressed, the redundancy switch signals 17a, 17b, and 17c are switched at the same time. Note that the resistor 19 is a resistor for limiting an excessive current.

Since this conventional device is configured as described above, it operates as follows. That is, the controller 1
6 calculates the position of the bucket and determines that it is in the safety zone, the controller 16 sets the maximum rated current Iam
ax, Ibmax, and Icmax are output. At this time, the proportional electromagnetic pressure reducing valves 5a, 5b and 5c are fully opened, and the oil pressures of the oil passages 11a, 11b and 11c are
a, 12b, 12c, the main switching valves 3a, 3b, 3c
Act on each pilot port. Therefore, when it is in the safety zone, it operates in the same manner as when the proportional pressure reducing valves 5a, 5b, 5c are not interposed.

Next, when it is determined that the bucket is in the stop range, the controller 16 sets the command currents Ia, Ib, Ic to the solenoids of the pressure reducing valves 5a, 5b, 5c to zero. At this time, the secondary ports of the proportional electromagnetic pressure reducing valves 5a, 5b, 5c are electrically connected to the oil tank T, and the oil passages 12a, 12b,
The hydraulic pressure of 12c becomes zero. Accordingly, the switching valves 3a, 3
b and 3c are in the state of the center position shown in FIG. 5, and the piston of each cylinder stops. When the bucket is in the deceleration range, the command currents Ia, Ib, Ic are between zero and the maximum rating, and the oil pressures of the oil passages 11a, 11b, 11c are reduced and appear in the oil passages 12a, 12b, 12c. Therefore,
At this time, the movement of the bucket is decelerated.

When the operator of the work machine determines that the operation of the controller is not normal during the operation, the user presses the redundancy switching button 18 to output a redundancy switching signal and switch the redundancy switching relays 17a, 17b and 17c to the power supply side. . By this switching, the controller 16 is disconnected from the operation system of the work machine, and the constant current is reduced by the proportional pressure reducing valves 5a, 5b, 5
Flow to the solenoid of c. Thus, the operator can continue the operation without the interference prevention device operating.

[0012]

As described above,
In this conventional device, when the signal line from the controller 16 to the proportional pressure reducing valve 5 is broken, no command current flows. Therefore, the cylinder piston stops, and the operator notices the abnormality and stops the operation. Therefore, this conventional device is excellent in that it is configured as a fail-safe system.
However, during the operation of the work machine, it is usually in the safety area.At this time, since the maximum current flows through the electromagnetic pressure reducing valve, the power consumption is large, the power generation capacity of the engine must be increased, and the heat radiation of the solenoid There was a problem that the design had to be taken into account. In addition, there is a problem that a circuit is complicated because redundant switching relays are individually required, and a problem that a resistor having large power consumption is required because three currents flow through the limiting resistor. Furthermore, even when the redundant switching relay is connected to the power supply side, there is a problem that the working machine cannot be moved when the wiring between the redundant switching relay and the solenoid of the proportional pressure reducing valve is broken.

An object of the present invention is to provide an interference prevention device that consumes less power. Another object is to provide an interference prevention device that stops a work machine when an abnormality is detected and prevents danger.

[0014]

According to a first aspect of the present invention, there is provided an interference prevention device comprising: a pilot hydraulic line between a remote control operating valve and a main switching valve; When the work machine is in the safety zone, a main control means is provided for controlling a small current to flow to the solenoid of the inverse proportional solenoid pressure reducing valve, and when the work machine is in the stop zone, the main control means is controlled to flow the maximum current. It is characterized in that detection means for detecting an abnormality in the operation of the proportional electromagnetic pressure reducing valve is provided.

Therefore, this device operates as follows. When the solenoid is in the safety range, zero or a small current flows through the solenoid of the electromagnetic pressure reducing valve, but the primary oil pressure of the electromagnetic pressure reducing valve appears as the secondary oil pressure as it is. Therefore, the operation can be performed in a state where the pressure is not reduced by the electromagnetic pressure reducing valve. Also, when it comes to the stop region, the maximum current flows through the solenoid. At this time, the secondary hydraulic pressure of the electromagnetic pressure reducing valve becomes zero, the main switching valve stops at the center, and the connected actuator also stops.

Further, the interference prevention device according to claim 2 is
An inverse proportional electromagnetic pressure reducing valve is provided in the pilot hydraulic line between the remote control operating valve and the main switching valve, and when the working machine is in a safe area, a small current flows through the solenoid of the inverse proportional electromagnetic pressure reducing valve and is in a stop area. Sometimes, in an interference prevention device provided with main control means for controlling the maximum current to flow, a shut-off valve is provided upstream of the remote control operation valve, and
An abnormality detecting means for detecting an abnormality in the operation of the inverse proportional electromagnetic pressure reducing valve is provided, and an on / off control means for turning off the shut-off valve when the abnormality detecting means detects an abnormality is provided.

Therefore, this device performs the following operation in addition to the same operation as the first embodiment. That is, when the electromagnetic pressure reducing valve does not operate normally, when the abnormality is detected by the abnormality detecting means, the shut-off valve is turned off, the remote control operation valve does not operate, and the work machine stops.

Further, the interference prevention device according to a third aspect of the present invention provides the interference prevention device according to the second aspect, wherein the switching device for supplying a current from a power supply to one of the control unit and the shut-off valve. And switching control means for connecting the switching means to the shut-off valve when an abnormality is detected by the abnormality detecting means, and connecting to the control means at normal times when no abnormality is detected. And

This work machine performs a normal operation when no abnormality is detected, and when an abnormality is detected, the switching control means connects the switching means to the shut-off valve side so that the remote control operating valve becomes operable.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing a configuration of an embodiment of the present invention. Conventional example in FIG. 1 (FIGS. 5 and 6)
The same components as those described above are denoted by the same reference numerals, and description thereof is omitted. FIG. 2 is a graph showing the relationship between the command current of the inverse proportional electromagnetic pressure reducing valve and the secondary hydraulic pressure. FIG. 3 is a diagram showing a detailed configuration of the controller 23. FIG. 4 is a diagram illustrating an example of a specific configuration of the disconnection detection unit of the controller 23.

In FIG. 1, reference numerals 20a, 20b,
20c is an inverse proportional electromagnetic pressure reducing valve. Inverse proportional solenoid pressure reducing valve 2
The primary ports 0a, 20b and 20c are connected to the oil passages 11 respectively.
a, 11b, 11c to control the remote control valves 7a, 7b, 7c
Is connected to the secondary side port of The other primary port is connected to the oil tank. Also, an inverse proportional electromagnetic pressure reducing valve 2
0a, 20b, and 20c are connected to the oil passages 12 respectively.
a, 12b and 12c are connected to the left pilot ports of the main switching valves 3a, 3b and 3c. The right pilot port is similarly connected to a secondary port of an inverse proportional solenoid valve not shown.

Inverse proportional electromagnetic pressure reducing valves 20a, 20b, 20c
FIG. 2 shows the relationship between the command current I of FIG. In FIG. 2, when the hydraulic pressure P is supplied to the primary port and the command current having the maximum value Imax is supplied to the solenoid, the hydraulic pressure of the secondary port is zero, and the command current I is set to zero. In other words, when I = 0, the hydraulic pressure A of the secondary port is substantially the same as the primary hydraulic pressure P. In addition, the command current I
Is 0 <I <Imax, the hydraulic pressure A of the secondary port is P
>A> 0.

Inverse proportional electromagnetic pressure reducing valves 20a, 20b, 20c
The solenoids 30a, 30b, 30c of the controller 2
1 is connected to the output terminal by wiring. Further, the upstream side of the pilot valves 7a, 7b, 7c and the pilot pump 9
A shutoff valve 32 is inserted in an oil passage between the oil tank 10 and the oil tank 10. The solenoid of the shut-off valve 32 is connected to the output terminal of the on / off switch 28 via a wire 40 via a stop switch 33 and a diode 34 (see FIG. 3). The input side of the on / off switch 28 is connected to the output terminal b of the switching relay 35. The on / off switch 28 is provided inside or outside the controller 21, and the control end of the on / off switch 28 is controlled by the controller 21.

The input terminal of the switching relay 35 is connected to a DC power supply 36. Another output terminal a of the switching relay 35
Is connected to the wiring 40 between the stop switch 33 and the output side of the diode 34. The switching signal input terminal of the switching relay 35 is connected by a wiring 41 to a push button 42 for inputting a redundant switching signal provided at an appropriate position in the cab. The push button 42 is connected on the a side in the concave state, and is connected on the b side in the convex state. The switching relay 35 is a DC power supply 36
The electric current is selectively supplied to the on / off switch 28 or the shut-off valve 32, and may be constituted by a mechanical switching relay or an electronic switching relay.

The controller 21 comprises a CPU (Central Processing Unit), a RAM and a ROM memory, an input / output port and the like, and its functional block is shown in FIG. FIG.
, The output signals of the boom tilt angle detection sensor 15a, the arm tilt angle detection sensor 15b, and the offset angle detection sensor 15c are supplied to an amplifier (not shown) and an A / D
The data is recorded as digital data in a memory (not shown) via a converter.

The bucket position calculator 22 calculates and outputs the bucket position X from these data and data recorded in advance in the memory such as the rear boom length, the front boom length, the upper boom length, and the arm length. . The area determination unit 23 determines the current area R from the bucket position X and the data of each boundary area stored in the memory in advance. The control signal generator 24 generates and outputs control signal currents Ia, Ib, and Ic for the current region R. The control signals Ia, Ib, Ic may have the same value or different values. The control signal currents Ia, Ib, Ic are supplied via the driver 25 to the inverse proportional electromagnetic pressure reducing valves 20a, 20b, 20c.
A command current is output to the solenoids 30a, 30b, and 30c of FIG.

The solenoids 30a, 30b, 30c
Is input to the disconnection detection unit 27. The disconnection detecting section 27 can be configured, for example, as shown in FIG. In FIG. 4, the output terminal of the solenoid 30a is grounded via a resistor 37. The resistance value of the resistor 37 is set to a value sufficiently lower than the resistance value of the solenoid 30a, and a value is selected so that the influence on the inverse proportional electromagnetic pressure reducing valve 20a can be ignored. The input terminal of the resistor 37 is connected to an A / D converter 38 via an amplifier (not shown). A
The output terminal of the / D converter 38 is connected to the voltage detection unit 39. With the above configuration, the disconnection detection unit 27 detects a voltage drop due to the resistor 37 by the voltage detection unit 39 when a current flows through the solenoid, and detects whether the wiring between the controller 21 and the solenoid is disconnected. . If the wire is disconnected, the detection signal H is set to "1". If the wire is not broken, the detection signal H is set to "0". Note that the configuration of the disconnection detection unit is not limited to this.

The disconnection detecting section 27 outputs a detection signal H to the fail detecting section 26. The failure detector 26 detects the detection signal H
Is "1", the fail signal F is set to "1", and when the detection signal H is "0", the fail signal F is set to "0".
It outputs a fail signal F. Further, the failure detection signal unit 26 may detect a failure of the area determination unit 23 and the like. For example, the bucket position detector 2
When it is determined that the bucket position X of No. 2 and the region R of the region determining unit 23 do not satisfy the predetermined relationship, it is determined that a failure has occurred,
A fail signal “1” is output. The output of the fail detector 26 is connected to the control terminal of the on / off switch 28.

When the fail signal is "1", the on / off switch 28 is turned off and the shutoff valve 32 is shut off. When the fail signal is "0", the on / off switch 28 is turned on, and the pilot pump port and the secondary port of the shut-off valve 32 are brought into conduction. Therefore, when the failure signal is "1", the primary hydraulic pressure of the remote control valves 7a, 7b, 7c is 0.
Becomes inoperable. When the failure signal is "0", the on / off switch 28 is turned on, and the current from the power supply 36 flows through the diode 34 and the stop switch 33 through the solenoid of the shut-off valve 32, and the pilot pump 9 The pressure oil flows to the remote control valves 7a, 7b, 7c, and the remote control valves can operate normally.

Since the present embodiment is configured as described above, it operates as follows. When the interference prevention device is operated, the angle data from the detection sensors 15a, 15b, and 15c is taken into the bucket position calculator 22, and the bucket position X is calculated. The region determining unit 23 determines, based on the calculated bucket position, where the bucket is in the safety region, the deceleration region, or the stop region, and outputs a region signal R. The control signal generator 24 outputs control signals Ia, Ib, Ic based on the area signal R. Control signals Ia, I
b and Ic take the following values. The minimum currents Iamin, Ibmin, Icmin are output when the vehicle is in the safety zone, and the maximum currents Iamax, Ibmax, Icm when the vehicle is in the stop zone.
ax is output. Iamax> Ia when in deceleration range
> Iamin, Ibmax>Ib> Ibmin, Icm
ax>Ic> Icmin.

Command currents Ia, I from controller 21
b, Ic, the inverse proportional electromagnetic pressure reducing valves 20a, 20b, 20
c operates, and the secondary hydraulic pressure A is changed with respect to the primary hydraulic pressure P in FIG.
Output according to the characteristics of Thereby, the pilot oil pressure is transmitted to the pilot ports of the main switching valves 3a, 3b, 3c as it is in the safety region, but is transmitted in a reduced pressure in the deceleration region. In the stop region, the pilot pressure of the main switching valve becomes almost zero, and the operation of each arm stops.

Also, the inverse proportional electromagnetic pressure reducing valves 20a, 20b,
Since at least the minimum current flows through the resistor 20c, a voltage is generated across the resistor 31 and the disconnection detecting unit 27 detects the presence or absence of the disconnection. If disconnection is detected, or
When the failure detection unit detects an abnormality from the relationship between the bucket position X and the region R, the on / off switch 28 is turned off, and the shutoff valve 32 is turned off. As a result, the operation is disabled.

In this case, when the push button 42 is pressed, the switching relay 35 is switched to the side a, current flows from the power source 36 directly to the solenoid of the shut-off valve 32, and the pressure oil of the pilot pump 9 is supplied to the remote control operating valve 7a. , 7b, 7
c. At the same time, no current is supplied from the power supply 36 to the driver 25, so that the output current of the driver 25 becomes zero and the inverse proportional pressure reducing valves 20a, 20b, 20c
Is in a no-pressure state. Therefore, the operation can be performed in a state where the interference prevention device does not operate.

Although the embodiments and examples of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to the above description or examples, and does not depart from the gist of the present invention. Even if there is a change in the design, etc., this invention is included. For example, it is also possible to detect other abnormalities as abnormality detecting means. The command current is Im
Zero current may be used instead of in.

[0035]

As described above, according to the present invention,
There is an effect that the amount of electric power flowing through the solenoid of the electromagnetic pressure reducing valve is reduced. Further, in the claimed invention, the work implement is stopped when an abnormality occurs, so that there is an effect that the work can be performed safely.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing characteristics of an inverse proportional electromagnetic pressure reducing valve.

FIG. 3 is a functional block diagram of a controller.

FIG. 4 is a diagram showing a specific configuration of a disconnection detection unit.

FIG. 5 is a diagram showing a pilot oil pressure control method of a conventional interference prevention device.

FIG. 6 is a diagram showing a configuration of a conventional example.

FIG. 7 is a diagram showing characteristics of a proportional electromagnetic pressure reducing valve.

[Explanation of symbols]

 3a, 3b, 3c Main switching valve 7a, 7b, 7c Remote control operation valve 20a, 20b, 20c Inverse proportional electromagnetic pressure reducing valve 21 Controller (main control means) 26 Failure detecting section (abnormality detecting section) 27 Disconnection detecting section (abnormality detecting section) ) 28 ON / OFF switch (ON / OFF control means) 32 Shut-off valve 35 Redundancy switching relay (Switching means) 42 Redundancy switching button (Switching control means)

Claims (3)

(57) [Claims] An inverse proportional electromagnetic pressure reducing valve is provided in a pilot hydraulic line between a remote control operating valve and a main switching valve, and when a working machine is in a safety zone, a small current flows through a solenoid of the inverse proportional electromagnetic pressure reducing valve. A main control means for controlling a maximum current to flow when the engine is in a stop zone, and a detection means for detecting an abnormality in operation of the inverse proportional pressure reducing valve by the small current. Interference prevention equipment for machines and the like. 2. An inverse proportional electromagnetic pressure reducing valve is provided in a pilot hydraulic line between a remote control operating valve and a main switching valve, and when a working machine is in a safety zone, a minute current flows through a solenoid of the inverse proportional electromagnetic pressure reducing valve. In an interference prevention apparatus provided with main control means for controlling a maximum current to flow when in a stop region, a shut-off valve is provided upstream of the remote control operation valve, and an operation of the inverse proportional electromagnetic pressure reducing valve is provided. An interference prevention device for a construction machine or the like, comprising: abnormality detection means for detecting an abnormality in the apparatus; and on-off control means for turning off the shut-off valve when the abnormality detection means detects an abnormality. 3. The interference prevention device further comprises a switching unit for supplying a current from a power supply to one of the control unit and the shut-off valve, and an abnormality is detected by the abnormality detection unit. 3. A construction machine or the like according to claim 2, further comprising switching control means for connecting the switching means to the shut-off valve when the abnormality occurs and connecting the control means to the control means when no abnormality is detected. Interference prevention device.