JP2000127806A - Emergency stop device for construction vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid a dangerous condition by making a vehicle impossible to travel when oil pressure abnormality oocurs in a forward-reverse travel switching hydraulic driving system. SOLUTION: This device is provided with a first of pressure detecting means 16 to detect an oil pressure at a first pilot oil line 15 which runs from a solenoid proportioning pressure reducing valve for forward travel 5 to a forward-reverse travel switching valve 4, and a second oil pressure detecting means 18 to detect an oil pressure at a second pilot oil line 17 which runs from a solenoid proportioning pressure reducing valve for reverse travel 6 to the forward-reverse travel switching valve 4. This device is also provided with an abnormality detecting means 7 to detect abnormality in the first and the second pilot oil lines 15, 17 by collating a speed change command which is output from a shift lever 12 with a detecting signal from the first and the second oil pressure detecting means 16, 18, and an abnormality processing means to urgently cut off a connection between an output shaft of a hydraulic motor 3 and a vehicular traveling shaft 10 by outputting an open command to a solenoid proportioning pressure reducing valve for a clutch 11 when an abnormal signal is output from the abnormality detecting means 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traveling abnormal stop device for a construction vehicle having two power transmission means, hydraulic drive traveling and mechanical drive traveling.

[0002]

2. Description of the Related Art FIG. 6 shows a hydraulic circuit of a power transmission control device of this type of hydraulic drive system.

In FIG. 6, a hydraulic pump 2 is connected to an engine 1
The hydraulic motor 3 is driven by the
Is driven. A forward / reverse switching valve 4 is interposed in the hydraulic circuit between the hydraulic pump 2 and the hydraulic motor 3, and the valve 4 switches between forward traveling and reverse traveling.

The forward / reverse switching valve 4 is switched by an electromagnetic proportional pressure reducing valve 5 for forward movement and an electromagnetic proportional pressure reducing valve 6 for backward movement. The forward proportional electromagnetic pressure reducing valve 5 has a T / M
(Transmission) In response to a forward electric command from the controller 7, a pilot pressure is applied to one pressure receiving surface of the forward / reverse switching valve 4, and the forward / backward switching valve 4 is switched to the forward shift position. The reverse electromagnetic proportional pressure reducing valve 6 applies a pilot pressure to the other pressure-receiving surface of the forward / reverse switching valve 4 in response to a reverse electrical command from the T / M controller 7, and moves the forward / backward switching valve 4 to the reverse shift position. Switch.

The output shaft of the hydraulic motor 3 is connected to a transmission 8. In this case, a partial configuration of the transmission 8 is shown. The output shaft of the hydraulic motor 3 is
The first-speed clutch 9 is connected to the propeller shaft 10 of the traveling shaft via several gears, so that hydraulic drive power is output to the propeller shaft 10 of the traveling shaft. As shown in FIG. 2, the second-speed and third-speed transmission mechanism of the high-speed stage connects the output shaft 19 of the engine 1 to the output shaft 10 of the transmission 8 via the second-speed clutch 20 and the third-speed clutch 21. A second-speed planetary gear mechanism 23 and a third-speed planetary gear mechanism 22 are provided, and the power of the engine 1 is directly output to the traveling shaft 10 only by a mechanical mechanism.

The first-speed clutch 9 is a clutch of a hydraulic drive output for outputting the rotational power of the hydraulic motor 2, and its engagement and disengagement control is performed by a first-speed electromagnetic proportional pressure reducing valve 11. The first speed electromagnetic proportional pressure reducing valve 11 outputs a hydraulic pressure for engaging the first speed clutch 9 in response to a first speed electric command from the T / M controller 7.

The shift lever 12 generates, as an electric signal, a shift command for automatic shifting corresponding to the operation of the operator.

The T / M controller 7 includes a shift lever 1
When a reverse speed change command (R) is input from the second gear, a reverse electric command is output to the reverse electromagnetic proportional pressure reducing valve 6 and a first speed electric command is output to the first speed electromagnetic proportional pressure reducing valve 11 to hydraulically drive the vehicle. The first-speed driving reverse is enabled. When the first speed fixing command (L) is input from the shift lever 12, a forward electric command is output to the forward electromagnetic proportional pressure reducing valve 5, and
A first-speed electric command is output to the first-speed electromagnetic proportional pressure reducing valve 11 to bring the vehicle into a hydraulically-driven first-speed advanceable state. Further, when the second speed fixing command (2) is input from the shift lever 12, an electromagnetic proportional pressure reducing valve (not shown) for a second speed clutch is driven to bring the vehicle into a mechanically driven second speed advanceable state. Also, when a drive command (D) is input from the shift lever 12, an appropriate speed stage is calculated based on the vehicle speed, the engine speed, and the like, and based on this, the first gear of the hydraulic drive is changed to the second gear of the mechanical drive.
Automatic shift control is performed for the first and third speeds.

[0009]

In such a hydraulic traveling drive system, various erroneous operations may occur due to foreign matter or dust mixed in the hydraulic circuit. For example, when dust or foreign matter is mixed in each pilot oil passage from the electromagnetic proportional pressure reducing valve 5 for forward movement or the electromagnetic proportional pressure reducing valve 6 for backward movement to the forward / reverse switching valve 4, the electromagnetic proportional pressure reducing valves 5 and 6 bite. In rare cases, the valves may not be able to operate, and a malfunction may occur with the electromagnetic proportional pressure reducing valves 5 and 6 being turned on. In such a case, the vehicle may run in a direction opposite to the command direction. Is very dangerous.

That is, if a malfunction occurs, for example, in which the output of the pilot pressure oil from the electromagnetic proportional pressure-reducing valve 5 does not stop due to a malfunction due to the contaminant, the forward / reverse switching valve 4 is shifted to the forward position. Will remain
The hydraulic motor 3 also keeps rotating in the forward direction. In such a case, it is assumed that the shift lever 12 is switched to neutral (N), the first speed clutch 9 of the transmission 8 is disengaged, the forward traveling is interrupted, and then the shift lever 12 is switched to reverse traveling (R). In this case, the T / M controller 7 outputs a first speed electric command and a reverse electric command. However, the forward / backward switching valve 4 cannot be switched to the reverse position due to the above-described failure, and the hydraulic motor 3 also remains rotating in the forward direction.

Therefore, if the driver starts and suddenly starts the vehicle without knowing such a state, the vehicle travels forward, which is different from the driver's intention, which is very dangerous.

The present invention has been made in view of the above circumstances, and when a hydraulic abnormality occurs in a hydraulic pilot pressure system for operation control for forward / reverse switching, the vehicle cannot travel and is in a dangerous state. It is an object of the present invention to provide a traveling abnormal stop device for a construction vehicle that avoids the above problem.

Further, according to the present invention, when an emergency drive system is provided which enables the vehicle to travel using an electric circuit for emergency travel, the emergency drive system is operated without noticing the above-mentioned trouble. It is an object of the present invention to provide an abnormal traveling stop device for a construction vehicle in which the traveling of the vehicle is disabled even when the traveling is stopped.

Further, according to the present invention, even if the vehicle cannot be driven by the emergency driving circuit,
It is an object of the present invention to provide a traveling abnormal stop device for a construction vehicle that allows the vehicle to travel by mechanical power drive.

[0015]

According to the first aspect of the present invention, a hydraulic pump driven by an engine (1) is provided.
(2), a hydraulic motor (3) that is rotationally driven by hydraulic oil discharged from the hydraulic pump (2), and a hydraulic motor (3) that switches the flow direction of the hydraulic oil discharged from the hydraulic pump (2). A forward / reverse switching valve (4) for switching between forward and reverse by switching between forward and reverse rotation, and a hydraulically operated clutch (9) for connecting and disconnecting an output shaft of the hydraulic motor (3) and a vehicle traveling shaft (10). A traveling shaft for shifting the rotational power of the hydraulic motor (3).
A transmission (8) including a power transmission portion of a hydraulic drive for transmission to (10) and a pilot oil pressure (15) for switching the forward / reverse switching valve (4) to a forward switching position in response to a forward command. Electromagnetic proportional pressure-reducing valve for forward (5), and a solenoid-operated proportional pressure-reducing valve for outputting a pilot oil pressure (17) for switching the forward / reverse switching valve (4) to a reverse switching position in response to a reverse command (6) An electromagnetic proportional pressure reducing valve (11) for releasing the engagement of the hydraulically actuated clutch (9) of the transmission (8) in response to the release command, and a shift lever (12) for generating a shift command. And this shift lever
(12) In a construction vehicle comprising: a control means (7) for performing output control of the forward command, the reverse command, and the clutch engagement command based on the shift command,
The first pilot oil passage (1) from (5) to the forward / reverse switching valve (4)
5) a first oil pressure detecting means (16) for detecting an oil pressure, and a second oil pressure detecting means (16) from the electromagnetic proportional pressure reducing valve for backward movement to a forward / reverse switching valve (4).
Second oil pressure detecting means (18) for detecting the oil pressure of the pilot oil passage (17), a shift command output from the shift lever (13), and the first and second oil pressure detecting means (16, 18). Abnormality detection means (7) for detecting an abnormality of the first and second pilot oil passages (15, 17) by comparing the detection signals of (1) and (2).
When an abnormality signal is output from the abnormality detection means (7), an open command is output to the clutch electromagnetic proportional pressure reducing valve (11) to output the output shaft of the hydraulic motor (3) and the vehicle traveling shaft (10). And (7) an emergency processing means (7) for urgently breaking the connection.

According to the first aspect of the invention, the first pilot oil passage from the forward electromagnetic pressure reducing valve to the forward / reverse switching valve and the second pilot oil passage from the reverse electromagnetic proportional pressure reducing valve to the forward / reverse switching valve. Oil pressure detecting means such as a pressure switch for detecting the oil pressure of these oil passages is arranged in the oil passage. Then, by comparing the detection output of these oil pressure detection means with a shift command output from the shift lever, the first and second gears are detected.
If an abnormality signal is output from the abnormality detecting means, an open command is output to the electromagnetic proportional pressure reducing valve for the clutch to urgently connect the output shaft of the hydraulic motor and the vehicle running shaft. I try to shut it off.

As described above, according to the first aspect of the present invention, when a hydraulic abnormality occurs in the hydraulic drive system for switching between forward and reverse, the transmission is disconnected so that the vehicle cannot travel. However, it is possible to reliably avoid a danger such as running the vehicle in the reverse direction without noticing the abnormality. Further, in the present invention, when the vehicle is emergency stopped, instead of turning off the engine, the transmission is cut off, so if an emergency driving device is mounted,
By operating the emergency driving device, the vehicle can travel, and thereby the faulty vehicle can be evacuated to the evacuation area.

According to a second aspect of the present invention, in the first aspect of the invention, the emergency operation for causing the vehicle to travel in the forward traveling mode or the reverse traveling mode by another electric circuit other than the command from the control means (7). Switch means (30, 40)
When the forward running mode is selected by the emergency operation switch means (30, 40), the clutch electromagnetic proportional pressure reducing valve (11) and the forward electromagnetic proportional pressure reducing valve (5) are turned on, and the emergency operation When the reverse running mode is selected by the switch means (30, 40), an emergency signal for outputting an emergency signal to turn on the clutch electromagnetic proportional pressure reducing valve (11) and the reverse electromagnetic proportional pressure reducing valve (6). An electric circuit, and when the forward traveling mode is selected, the emergency signal is forcibly turned off in response to a detection output of the second oil pressure detection means (18), and the reverse An emergency stop circuit (33, 34) for forcibly turning off the emergency signal in accordance with the detection output of the first oil pressure detecting means (16) when the drive mode is selected is provided for the emergency drive. The feature is that it is provided in the electric circuit. And

According to a second aspect of the present invention, when an emergency operation circuit is provided as a backup for malfunction of the control means, the hydraulic abnormality of the hydraulic pilot pressure system for operation control for forward / reverse switching occurs. In this case, the driver operates the emergency driving circuit without realizing such a trouble to avoid a situation in which the vehicle can run.

That is, the forward / reverse switching is performed when the forward-side pilot pressure of the forward / backward switching valve is raised when the forward traveling mode of the emergency operation is selected, or when the backward traveling mode of the emergency operation is selected. When the forward pilot pressure of the valve is raised, the vehicle may run in the reverse direction.In such a case, the emergency signal for emergency operation output by the emergency operation circuit is forcibly turned off. I do.

Therefore, according to the second aspect of the present invention, when the above-described trouble occurs, even if the driver tries to run the vehicle by activating the emergency driving circuit by mistake,
The vehicle can no longer be run, thereby making it possible to reliably avoid danger such as reverse running of the vehicle.

According to a third aspect of the present invention, in the second aspect of the present invention, the transmission (8) includes a planetary gear power transmission mechanism (23) for connecting an output shaft of an engine (1) and the vehicle running shaft (10). ) And a second hydraulically operated clutch (2) for connecting and disconnecting the power transmission by the planetary gear power transmission mechanism (23).
0), and the second from the control means (7).
The second hydraulically actuated clutch in response to the
(20) a second clutch electromagnetic proportional pressure-reducing valve (25) for releasing the engagement, and a second emergency operation switch means (40) for causing the vehicle to run in an emergency, further comprising the control means (7). When the second emergency operation switch means (40) is detected to be turned on, the second clutch electromagnetic proportional pressure reducing valve (25) is forcibly turned on and the second hydraulic actuation of the transmission (8) is performed. When the emergency traveling stop circuit makes the traveling of the vehicle impossible by engaging the clutch (25), the traveling of the vehicle is enabled by mechanical power drive.

According to the third aspect of the present invention, the output of the engine is provided separately from the hydraulically driven traveling system which transmits the output of the engine to the traveling shaft via a hydraulic pump, a forward / reverse switching valve, a hydraulic motor, and a hydraulically operated clutch. Is applied to a vehicle having a mechanically driven traveling system that transmits the driving force to the traveling axis only by a mechanical mechanism.

The transmission has a planetary gear power transmission mechanism for connecting the output shaft of the engine and the vehicle running shaft, and a power transmission connection by the planetary gear power transmission mechanism.
And a second hydraulically actuated clutch for performing disconnection. When the second hydraulically actuated clutch is engaged, the output of the engine is:
The power is transmitted to the traveling shaft via the second hydraulically operated clutch and the planetary gear power mechanism.

According to the second aspect of the present invention, when an abnormality in the hydraulic pressure of the operation control hydraulic pilot pressure system for switching between forward and reverse occurs as described above, the emergency operation circuit is activated even if the emergency operation circuit is activated. Since the output emergency signal for emergency operation is forcibly turned off, the vehicle cannot travel using the hydraulically driven traveling system.

Therefore, in the invention of claim 3, a second emergency operation circuit is provided as final vehicle traveling means. That is, when the control means detects that the second emergency operation switch means is turned on, the control means forcibly turns on the second clutch electromagnetic proportional pressure reducing valve for engaging the second hydraulically operated clutch of the transmission. This enables the vehicle to travel using the mechanical drive traveling system.

As described above, according to the third aspect of the present invention, the vehicle can be driven even when the emergency traveling stop circuit of the second aspect makes the traveling of the vehicle impossible. Can be evacuated to a place.

[0028]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a schematic hydraulic circuit diagram showing an embodiment of the present invention, and shows a forward-backward traveling hydraulic drive system of a hydraulic shovel and a control operation portion thereof.

In the embodiment of FIG. 1, FIG.
In contrast to the prior art shown in FIG.
Are added, and the same components as those shown in FIG. 6 are denoted by the same reference numerals.

That is, in FIG.
Is driven by the engine 1, and the hydraulic motor 3 is driven by the discharge pressure oil. A forward / reverse switching valve 4 is interposed in the hydraulic circuit between the hydraulic pump 2 and the hydraulic motor 3, and the valve 4 switches between forward traveling and reverse traveling.

The forward / reverse switching valve 4 is switched by an electromagnetic proportional pressure reducing valve 5 for forward movement and an electromagnetic proportional pressure reducing valve 6 for backward movement. The forward proportional pressure reducing valve 5 applies a pilot pressure to one pressure receiving surface of the forward / reverse switching valve 4 in response to a forward electric command from the T / M controller 7, and switches the forward / backward switching valve 4 to the forward position. . The reverse electromagnetic proportional pressure reducing valve 6 applies a pilot pressure to the other pressure-receiving surface of the forward / reverse switching valve 4 in response to a reverse electric command from the T / M controller 7, and switches the forward / backward switching valve 4 to the forward position. .

The output shaft of the hydraulic motor 3 is connected to the transmission 8.

FIG. 2 shows the internal structure of the transmission 8.

In FIG. 2, the output shaft of the hydraulic motor 3 is
A first speed clutch (a hydraulically actuated clutch in the claims) 9 is connected to a propeller shaft 10 of a traveling shaft via several gears. That is, in the case of the first speed, the power of the hydraulic motor 3 is transmitted to the traveling shaft via the power transmission line indicated by the arrow A in the figure. In the first speed, the power of the engine 1 is transmitted to the hydraulic pump 2 via the engine output shaft 19.

On the other hand, in the case of the second speed and the third speed, the second speed clutch (the second hydraulically actuated clutch in claims)
The output of the engine 1 travels directly without passing through the hydraulic pump 2 and the hydraulic motor 3 via the 20th and 3rd speed clutches 21 and the planetary gear mechanisms 22 and 23 provided for the clutches 20 and 21 respectively. Shaft propeller shaft 1
0 is transmitted. The illustrated arrow B indicates a power transmission line when the second speed is selected.

The engagement and disengagement of the first-speed clutch 9 shown in FIG. 2 is controlled by a first-speed electromagnetic proportional pressure reducing valve 11 (a clutch electromagnetic proportional pressure reducing valve in the claims) shown in FIG. Will be The first-speed electromagnetic proportional pressure reducing valve 11 has a T / M
In response to a first-speed electric command from the controller 7, a hydraulic pressure for engaging the first-speed clutch 9 is output.

The second-speed clutch 20 shown in FIG. 2 is engaged and disengaged by the second-speed electromagnetic proportional pressure reducing valve (second clutch electromagnetic proportional pressure reducing valve) 25 shown in FIG. Control is performed. The second-speed electromagnetic proportional pressure reducing valve 25 responds to a second-speed electric command from the
The hydraulic pressure for engaging the speed clutch 20 is output.

The engagement and disengagement of the third speed clutch 20 shown in FIG. 2 is controlled by the third speed electromagnetic proportional pressure reducing valve 26 shown in FIG. The 3rd-speed electromagnetic proportional pressure reducing valve 26 has a T / M
In response to a third-speed electric command from the controller 7, a hydraulic pressure for engaging the third-speed clutch 21 is output.

The shift lever 12 generates a shift command for automatic shifting corresponding to the operation of the operator as an electric signal.

The T / M controller 7 controls the shift lever 1
The first-speed electric command, the forward electric command, the reverse electric command, and the like are output in the above-described manner based on the shift command from the second and the information such as the engine speed and the vehicle speed.

In the embodiment shown in FIG. 1, a pressure switch 16 operated by the hydraulic pressure of the pilot oil passage 15 is provided in the pilot oil passage 15 from the forward electromagnetic pressure reducing valve 5 to the forward / reverse switching valve 4. ing. The pressure switch 16 is turned on when the oil pressure in the pilot oil passage 15 becomes equal to or higher than a predetermined pressure for shifting the forward / reverse switching valve 4 to the forward shift position, and outputs a forward pressure switch signal to the T / M controller 7. . Also, the electromagnetic proportional pressure reducing valve 6 for reverse
A pressure switch 18 that is operated by the hydraulic pressure of the pilot oil passage 17 is provided in the pilot oil passage 17 from the front to back switching valve 4. The pressure switch 18 is turned on when the oil pressure in the pilot oil passage 17 becomes equal to or higher than a predetermined pressure for shifting the forward / reverse switching valve 4 to the reverse shift position,
The reverse pressure switch signal is output to the T / M controller 7.

The T / M controller 7 controls the shift lever 1
The vehicle stop control is executed in a manner as shown in FIG. 3 by collating the shift command from the second with the forward / reverse pressure switch signal from the pressure switches 16 and 18.

The fact that the forward electric command is output from the T / M controller 7 to the forward electromagnetic proportional pressure reducing valve 5 means that
When the first speed fixed signal (L) is input from the shift lever 12 or the drive signal (D) is input, the T / M
This means that the first speed has been selected by the controller 7. The output of the reverse electric command from the T / M controller 7 to the reverse electromagnetic proportional pressure reducing valve 6 means that the reverse signal (R) is input from the shift lever 12.

The operation of the T / M controller 7 in each case shown in FIG. 3 will be described below.

(I) When neither the forward electric command nor the reverse electric command is output from the T / M controller 7, the forward pressure switch 16 and the reverse pressure switch 18
When both are off, neither the forward electric command nor the reverse electric command is output. This is a normal state and the vehicle has stopped.

(Ii) If the forward pressure switch 16 is turned on while neither the forward electric command nor the reverse electric command is output from the T / M controller 7, this will cause an ON failure (a failure that remains ON). 1)
1st-speed electromagnetic proportional pressure reducing valve 1 so as to turn off speed clutch 9
1 and issues an error. As a result, the vehicle stops.

(Iii) If the reverse pressure switch 18 is turned on while neither the forward electric command nor the reverse electric command is output from the T / M controller 7, this is an abnormality of the ON failure, so that the first speed A command is issued to the first-speed electromagnetic proportional pressure reducing valve 11 to turn off the clutch 9, and an abnormality is reported. As a result, the vehicle stops.

(Iv) If neither the forward electric command nor the reverse electric command is output from the T / M controller 7, the forward pressure switch 16 and the reverse pressure switch 18 are turned on. Therefore, the first-speed electromagnetic proportional pressure reducing valve 11 is turned off so that the first-speed clutch 9 is turned off.
And issues an alarm. As a result, the vehicle stops.

(V) When both the forward pressure switch 16 and the reverse pressure switch 18 are off while the forward electric command is output from the T / M controller 7, the forward electric command is output as it is. In this case, although it is abnormal, since the forward electronic proportional pressure reducing valve 5 is not an ON failure but an OFF failure, disconnection of the forward pressure switch 16 and the like in addition to the abnormality of the pressure reducing valve 5 can be considered as a factor.
An alarm is issued and the vehicle is allowed to run.

(Vi) If the forward pressure switch 16 is on while the T / M controller 7 outputs the forward electric command, the forward pressure switch 16 is normal. .

(Vii) If only the reverse pressure switch 18 is ON while the T / M controller 7 outputs the forward electric command, the first-speed clutch 9 is turned OFF because it is an abnormality of ON failure. Thus, a command is given to the first-speed electromagnetic proportional pressure reducing valve 11 and an abnormality is reported. As a result, the vehicle stops.

(Viii) When both the forward pressure switch 16 and the reverse pressure switch 18 are on when the forward electric command is output from the T / M controller 7, it is an abnormality of the ON failure, so that the first speed While giving a command to the first-speed electromagnetic proportional pressure reducing valve 11 to turn off the clutch 9,
Raise an error. As a result, the vehicle stops.

(Ix) If the forward pressure switch 16 and the reverse pressure switch 18 are both off while the reverse electric command is being output from the T / M controller 7, the reverse electric command is output as it is. In this case, it is abnormal, but since the electronic proportional pressure-reducing valve 6 for reverse is off, the disconnection of the reverse pressure switch 18 and the like in addition to the abnormality of the pressure-reducing valve 6 can be considered as a factor, so that the abnormality is alarmed. At the same time, the vehicle is allowed to run.

(X) If only the forward pressure switch 16 is ON while the reverse electric command is output from the T / M controller 7, it is an abnormality of the ON failure, and the first speed clutch 9 is turned OFF. Thus, a command is given to the first-speed electromagnetic proportional pressure reducing valve 11 and an abnormality is reported. As a result, the vehicle stops.

(Xi) If the reverse pressure switch 18 is on while the T / M controller 7 is outputting the reverse electric command, it is normal, so the forward command is given as it is, and the vehicle is allowed to move backward. .

(Xii) If both the forward pressure switch 16 and the reverse pressure switch 18 are on when the reverse electric command is output from the T / M controller 7, it is an abnormality of the ON failure, so that the first speed While giving a command to the first-speed electromagnetic proportional pressure reducing valve 11 to turn off the clutch 9,
Raise an error. As a result, the vehicle stops.

As described above, the T / M controller 7
Detects an abnormality in the pilot pressure applied to the forward / reverse switching valve 4 based on the detection outputs of the pressure switches 16 and 18, and in the event of an abnormality, the transmission 8
The first-speed clutch 9 is disengaged to stop the vehicle urgently.

FIG. 4 shows an electric circuit of a traveling drive system of the hydraulic excavator.

In FIG. 4, a shift signal (R, N, D, 2, 2) output according to the shift position of the shift lever 12 is shown.
1) is input to the T / M controller 7.

The emergency operation switch 30 is a switch having two states, ON and OFF, for operating an emergency operation circuit for emergency operation of the vehicle when the T / M controller 7 or the like malfunctions. Used in conjunction with the hex switch 40.

The emergency forward / reverse switch 40 is a switch for selecting whether to perform forward running or reverse running during an emergency operation. The forward / reverse (R), neutral (N), first speed forward running (F1), The switch has four states of fast forward running (F2).

When the first forward drive (F1) of the emergency forward / reverse switch 40 is selected, the vehicle is consequently set to 1 speed.
When the vehicle travels forward at the second speed and the second speed forward traveling (F2) is selected, the vehicle eventually travels forward at the second speed.
The emergency operation switch 40 is provided with a position for selecting these two different forward traveling states.
It is not intended to enable traveling at two speeds, but when forward traveling in the first forward traveling (F1) is impossible, the second forward traveling (F2) is selected to allow the vehicle to travel. This is to enable the vehicle to run forward. That is, F2
The position is provided as a reserve switch when forward traveling by the F1 position is impossible. The details will be described later.

The emergency command output from the emergency operation switch 31 is connected to the exciting coil of the forward / backward redundant relay 32 via the contact of the F2 relay 31.

The reverse emergency signal output when the reverse (R) of the emergency forward / reverse switch 40 is selected is transmitted to the reverse safety relay 33 via the normally open contact of the forward / backward redundant relay 32.
, And the solenoid of the electromagnetic proportional pressure reducing valve 6 for reverse drive.

The first forward movement of the emergency forward / reverse switch 40 (F
The 1-speed forward emergency signal output when 1) is selected is transmitted to the normally closed contact of the reverse safety relay 33 via the normally open contact of the forward / backward redundant relay 32 and the forward safety relay 34
, And a solenoid for a forward-reducing electromagnetic proportional pressure reducing valve 5.

The emergency forward / reverse switch 40 is moved forward in the second speed (F
The 2nd-speed forward emergency signal output when 2) is selected is connected to the exciting coil of the F2 relay 31.

When the exciting coil is not excited, the F2 relay 31 outputs the emergency command to the forward / reverse redundant relay 32 by connecting its contact to the a side, and outputs the signal from the relay 32.
When the two contacts are turned on and the second-speed forward emergency signal is output from the emergency forward / reverse switch 40 to excite the exciting coil, the contact is connected to the b side and the emergency command is used as an emergency speed change signal and the T / M Input to the controller 7.

The forward / backward redundant relay 32 turns on two contacts simultaneously by the input of the emergency signal, and is one of the first-speed forward emergency signal and the reverse emergency signal that are turned on by the selection operation of the emergency forward / reverse switch 40. Is output to the previous circuit.

The reverse safety relay 33 is a normally-closed contact for outputting a first-speed forward emergency signal or a reverse emergency signal input from the forward / backward redundant relay 32. The forward pressure switch 16 is connected to its exciting coil. ing. That is, when the forward pressure switch 16 is off, no current flows through the exciting coil of the reverse safety relay 33 even if either the first-speed forward emergency signal or the reverse emergency signal is input to the contact of the reverse safety relay 33. The contact of the reverse safety relay 33 maintains the ON state. However, when the forward pressure switch 16 is turned on when the reverse emergency signal is input to the contact of the reverse safety relay 33, a current flows through the exciting coil of the reverse safety relay 33. The flow reverse safety relay 33 is turned off.

That is, depending on the reverse safety relay 33, the emergency operation switch 30 and the emergency forward / reverse switch 40
The output of the reverse emergency signal is forcibly shut off when the forward pilot pressure of the forward / reverse switching valve 4 in FIG. .

A forward safety relay 34 is connected in series with the reverse safety relay 33. The output of the forward safety relay 34 is connected to the solenoid of the first-speed electromagnetic proportional pressure reducing valve 11.

The forward safety relay 34 is a normally closed contact that receives a first-speed forward emergency signal or a reverse emergency signal output from the reverse safety relay 33, and has the excitation coil connected to the reverse pressure switch 18 described above. ing. That is, when the reverse pressure switch 18 is off, no current flows through the exciting coil of the forward safety relay 34 even if a first speed forward emergency signal or a reverse emergency signal is input to the contact of the forward safety relay 34. The contact of the forward safety relay 34 is kept on. However, when the reverse pressure switch 18 is turned on when the forward emergency signal is input to the contact of the forward safety relay 34, a current flows through the exciting coil of the forward safety relay 34. The flow advance safety relay 34 is turned off.

That is, depending on the forward safety relay 34, the emergency operation switch 30 and the emergency forward / reverse switch 40
1, the output of the forward emergency signal is forcibly shut off when the reverse pilot pressure of the forward / reverse switching valve 4 in FIG. Will be done.

The forward electric command from the T / M controller 7 and the first-speed forward emergency signal from the forward / reverse redundant relay 32 are input to the solenoid of the forward proportional pressure reducing valve 5. The valve 5 can be activated by any of these input signals.

A reverse electric command from the T / M controller 7 and a reverse emergency signal from the forward / reverse redundant relay 32 are input to the solenoid of the reverse proportional pressure reducing valve 6. Can operate on any of these input signals.

To the solenoid of the first-speed electromagnetic proportional pressure reducing valve 11, a first-speed electric command from the T / M controller 7 and a reverse emergency signal or a first-speed forward emergency signal from the forward safety relay 34 are input. The reverse proportional pressure reducing valve 6 can be operated by any of these input signals.

Only the second speed electric command from the T / M controller 7 is input to the solenoid of the second speed electromagnetic proportional pressure reducing valve 25, and the second speed electromagnetic proportional pressure reducing valve 25 is operated only by the second speed electric command. I do.

FIG. 5 shows the operation of various valves and the like corresponding to the input states of the emergency operation switch 30 and the emergency forward / reverse switch 40 in the circuit configuration shown in FIG.

(A) When the emergency operation switch 30 is off, nothing is turned on in the configuration of FIG.

(B) When the emergency operation switch 30 is turned on and the reverse (R) position of the emergency forward / reverse switch 40 is selected, the electromagnetic proportional pressure reducing valve 6 for reverse and the electromagnetic proportional pressure reducing valve 11 for first speed are operated. As a result, the vehicle can travel backward. That is, when the emergency operation switch 30 is on,
The reverse emergency signal selectively output by operating the emergency forward / reverse switch 40 is input to the solenoid of the electromagnetic proportional pressure reducing valve 6 for reverse via the forward / backward redundant relay 32, and is also transmitted to the reverse safety relay 33 and forward safety relay 34. The signal is input to the solenoid of the first-speed electromagnetic proportional pressure reducing valve 11 via the first speed.

However, when the emergency operation switch 30 is on,
When the forward pressure switch 16 is turned on in the state where the reverse (R) position of the emergency forward / reverse switch 40 is selected, as described above, the reverse safety relay 3
3 is forcibly turned off, the electromagnetic proportional pressure reducing valve 6 for reverse is operated, but the electromagnetic proportional pressure reducing valve 11 for first speed is not operated. Therefore, the vehicle cannot travel backward.

(C) When the emergency operation switch 30 is turned on and the neutral (N) position of the emergency forward / reverse switch 40 is selected, only the first-speed electromagnetic proportional pressure reducing valve 11 is operated.

(D) When the emergency operation switch 30 is on and the first forward (F1) position of the emergency forward / reverse switch 40 is selected, the electromagnetic proportional pressure reducing valve 5 for forward movement and the electromagnetic proportional pressure reducing valve 11 for first speed are selected. Is operated, and the vehicle can travel forward in the first speed. That is, when the emergency operation switch 30 is ON, the first-speed forward emergency signal selectively output by operating the emergency forward / reverse switch 40 is input to the solenoid of the forward electromagnetic proportional pressure reducing valve 5 via the forward / backward redundant relay 32. At the same time, it is input to the solenoid of the first-speed electromagnetic proportional pressure reducing valve 11 via the reverse safety relay 33 and the forward safety relay 34.

However, when the emergency operation switch 30 is on,
When the reverse pressure switch 18 is turned on in the state where the first forward (F1) position of the emergency forward / reverse switch 40 is selected, the forward safety relay 34 is forcibly turned off as described above. Accordingly, the electromagnetic proportional pressure reducing valve 5 for forward operation is operated, but the electromagnetic proportional pressure reducing valve 11 for first speed is not operated. Therefore, the first speed forward running of the vehicle becomes impossible.

(E) When the emergency operation switch 40 is on and the second forward (F2) position of the emergency forward / reverse switch 40 is selected, the F2 relay 31 is operated to switch its contact to the b side, / M Controller 7 with F
2 The emergency speed change signal from the relay 31 is input, and
The speed electromagnetic proportional pressure reducing valve 25 is turned on. As a result, the vehicle can travel forward using the power line via the second speed clutch 20 shown in FIG.

That is, when the emergency operation switch 40 is turned on and the second forward (F2) position of the emergency forward / reverse switch 40 is selected, the contact of the F2 relay 31 is switched to the “b” side. Is input to the T / M controller 7 as an emergency shift signal. The T / M controller 7 outputs the second speed electric command to the solenoid of the second speed electromagnetic proportional pressure reducing valve 25 when the emergency shift signal is input. Accordingly, the second-speed electromagnetic proportional pressure reducing valve 25 is turned on, and the second-speed clutch 20 of the transmission 8 is engaged. Therefore, the vehicle can travel forward using the power line directly connected to the engine via the second speed clutch 20 shown in FIG.

As described above, in this embodiment, the pressure switches 16 and 1 for detecting the pilot pressure of the forward / reverse switching valve 4 are used.
When a hydraulic abnormality of the hydraulic drive system for switching between forward and backward is detected based on the detection outputs of the pressure switches 16 and 18, the transmission 8 is disconnected to make the vehicle unable to travel. Therefore, it is possible to surely avoid the danger that the driver reverses the vehicle without noticing the abnormality.

In the above-described embodiment, the normally closed reverse safety relay 33 and forward safety relay 34 are provided in the first emergency operation electric circuit including the forward / backward redundant relay 32 and the like. 33 and 34 are forcibly turned off by the operation of the forward pressure switch 16 and the reverse pressure switch 18, so that if a trouble occurs in the hydraulic drive system for switching back and forth as described above, the driver may mistakenly Therefore, even if the first emergency driving circuit is operated to cause the vehicle to travel, the vehicle remains stopped, so that danger such as reverse running of the vehicle due to a driver's operation error can be reliably avoided. become.

Further, in the above-described embodiment, as the final vehicle traveling means, the second emergency operation system having the operation input of the F2 position of the emergency forward / reverse switch 40 is provided. This second emergency operating system is completely separate from the first emergency operating system whose electrical circuits and power lines include said first emergency electrical circuit. Therefore, even when the reverse safety relay 33 and the forward safety relay 34 in the first emergency electric circuit are forcibly turned off due to the above-mentioned trouble and the vehicle cannot travel,
By operating the second emergency operating system, the vehicle can travel.

Incidentally, in this type of construction vehicle, there is a technique of turning off the engine in the case of various abnormalities. However, in the present apparatus, when the vehicle is stopped immediately, the transmission is cut off instead of turning off the engine. Therefore, if the emergency driving device is installed, the vehicle can be driven by operating the emergency driving device, and the faulty vehicle can be evacuated to the evacuation place. become.

In the above-described embodiment, both the backward running and the forward running can be performed in an emergency by the electric circuit for the emergency running. However, only one of the reverse running and the forward running can be performed. You may do so.

[Brief description of the drawings]

FIG. 1 is a block diagram of a hydraulic circuit showing an embodiment of the present invention.

FIG. 2 is a diagram showing an internal configuration of a transmission.

FIG. 3 is a table showing the relationship between the output of a pressure switch and the like and the output of a T / M controller.

FIG. 4 is a diagram showing an electric circuit of a traveling drive system according to the embodiment of the present invention.

FIG. 5 is a table showing operation modes of various valves and the like corresponding to various inputs of an emergency operation switch and an emergency forward / reverse switch.

FIG. 6 is a hydraulic circuit block diagram showing a conventional technique.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine 2 ... Hydraulic pump 3 ... Hydraulic motor 4 ... Forward / backward switching valve 5 ... Forward electromagnetic proportional pressure reducing valve 6 ... Reverse electromagnetic proportional pressure reducing valve 7 ... T / M controller 8 ... Transmission 9 ... 1st speed clutch 10 ... Propeller Shaft 11 ... 1st speed electromagnetic proportional pressure reducing valve 16 ... forward pressure switch 18 ... reverse pressure switch 20 ... 2nd speed clutch 21 ... 3rd speed clutch 25 ... 2nd speed electromagnetic proportional pressure reducing valve 26 ... 3rd speed electromagnetic proportional pressure reducing valve 30 ... Emergency operation switch 31 F2 relay 32 Forward / backward redundant relay 33 Reverse safety relay 34 Forward safety relay 40 Emergency forward / backward switch

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16D 48/02 F16D 25/14 640Q F-term (Reference) 3D041 AA72 AA73 AA74 AA76 AA80 AB07 AC07 AC14 AC15 AC16 AC22 AD02 AD30 AD35 AD36 AD51 AE14 AE32 AE38 AE39 AF00 3G093 AA05 AA10 AA15 BA12 CB14 DB00 DB07 DB11 EB00 EB03 EC04 3J057 AA03 BB04 GA53 GA54 GA61 GB28 GD08 HH04 JJ02

Claims (3)

[Claims] A hydraulic pump (2) driven by an engine (1), a hydraulic motor (3) rotationally driven by hydraulic oil discharged from the hydraulic pump (2), and a hydraulic pump (2). A forward / backward switching valve (4) that switches between forward and reverse by switching the flow direction of the discharge pressure oil to switch between forward and reverse rotation of the hydraulic motor (3), an output shaft of the hydraulic motor (3) and a vehicle traveling shaft ( A transmission having a hydraulically actuated clutch (9) for connecting and disconnecting with the hydraulic drive (10), and including a hydraulically driven power transmission part for shifting the rotational power of the hydraulic motor (3) and transmitting it to the traveling shaft (10).
(8), an electromagnetic proportional pressure reducing valve (5) for outputting a pilot oil pressure (15) for switching the forward / reverse switching valve (4) to a forward switching position in response to a forward command, and responding to a reverse command. A reverse electromagnetic proportional pressure reducing valve (6) for outputting a pilot oil pressure (17) for switching the forward / reverse switching valve (4) to a reverse switching position, and the transmission (8) in response to an engagement release command. An electromagnetic proportional pressure reducing valve (11) for engaging and disengaging the hydraulically actuated clutch (9), a shift lever (12) for generating a shift command, and a shift command for the shift lever (12). A control means (7) for performing output control of a forward command, a reverse command, and a clutch engagement command. First oil pressure detecting means (16) for detecting the oil pressure of the first pilot oil passage (15); A second hydraulic pressure detecting means (18) for detecting the hydraulic pressure of a second pilot oil passage (17) from the reverse electromagnetic proportional pressure reducing valve (6) to the forward / reverse switching valve (4); ) And the detection signals of the first and second oil pressure detection means (16, 18) to check the first and second pilot oil passages (1).
An abnormality detection means (7) for detecting an abnormality of (5, 17), and when an abnormality signal is output from the abnormality detection means (7), an open command is output to the clutch electromagnetic proportional pressure reducing valve (11). An abnormal processing means (7) for urgently disconnecting the connection between the output shaft of the hydraulic motor (3) and the vehicle traveling shaft (10). 2. An emergency operation switch means (3) for causing the vehicle to travel in a forward traveling mode or a reverse traveling mode by another electric circuit other than a command from the control means (7).
0,40) and when the forward running mode is selected by the emergency operation switch means (30,40), the electromagnetic proportional pressure reducing valve (1
1) and the forward electromagnetic pressure reducing valve (5) are turned on, and when the reverse running mode is selected by the emergency operation switch means (30, 40), the electromagnetic proportional pressure reducing valve for clutch (11) and the reverse An emergency traveling electric circuit that outputs an emergency signal for turning on the electromagnetic proportional pressure reducing valve (6), and further comprising the second hydraulic pressure detecting means (18) when the forward traveling mode is selected. And the emergency signal is forcibly turned off in response to the detection output of the first hydraulic pressure detection means (16) when the reverse traveling mode is selected. The abnormal running stop device for a construction vehicle according to claim 1, wherein an emergency running stop circuit (33, 34) for forcibly turning off the vehicle is provided in the emergency running electric circuit. 3. The transmission (8) includes an engine
A planetary gear power transmission mechanism (23) for coupling the output shaft of (1) and the vehicle running shaft (10), and the planetary gear power transmission mechanism (23);
And a second hydraulically-operated clutch (20) for connecting and disconnecting power transmission by the second hydraulically-operated clutch in response to a second engagement / disengagement command from the control means (7). A second clutch electromagnetic proportional pressure-reducing valve (25) for disengaging the clutch (20), and a second emergency operation switch means (40) for causing the vehicle to run in an emergency
When the control means (7) detects that the second emergency operation switch means (40) is turned on, the control means (7) forcibly turns on the second clutch electromagnetic proportional pressure reducing valve (25). The second hydraulically actuated clutch (25) of the transmission (8).
3. The construction vehicle according to claim 2, wherein the vehicle is driven by mechanical power even when the vehicle cannot be driven by the emergency stop circuit by engaging the emergency stop circuit. Abnormal travel stop device.