WO2005064170A1

WO2005064170A1 - Working vehicle and restart controlling method for working vehicle engine

Info

Publication number: WO2005064170A1
Application number: PCT/JP2004/019351
Authority: WO
Inventors: Masami Naruse
Original assignee: Komatsu Ltd.
Priority date: 2003-12-26
Filing date: 2004-12-24
Publication date: 2005-07-14
Also published as: GB2425368A; GB0612133D0; KR20060105032A; GB2425368B; JP4271685B2; JPWO2005064170A1; KR100934686B1

Abstract

In a working vehicle, in response to the operation of an operating lever by an operator after idling stop of the engine, control is effected to automatically restart the engine in such a manner that the working vehicle will not unexpectedly move. After the idling stop (S4) of the engine, when a lock lever is brought to a lock position (S5, YES), a hydraulic circuit is controlled to cause the working vehicle to enter in its inoperable state in which the working vehicle will not move (S6). Thereafter, when a particular operation is applied to the operating lever (S7, YES), the engine (16) is restarted (S8). After restarting of the engine, only when all operating levers are in the neutral position (S9, YES), the lock lever is released from its locked state (S10, YES). Whereupon the hydraulic circuit is gradually restored to its normal operable state, the working vehicle can move (S11).

Description

Specification

Work vehicle and engine restart control method for work vehicle

Technical field

The present invention relates to a work vehicle having an idling stop function and an engine restart function, and an engine restart control method for such a work vehicle.

Background art

[0002] Recently, it has been required to mount an idling stop control function on a work vehicle such as a work vehicle for energy saving and environmental protection! The idling stop control function is a function to automatically stop the engine when the idle state of the work vehicle, that is, a state in which the work vehicle waits while the engine is running. Work vehicles having an idling stop function are disclosed in Patent Documents 1 and 2, for example.

[0003] Patent Document 1: JP-A-2003-65097

Patent Document 2: Japanese Patent Application Laid-Open No. 2000-96627

[0004] In the work vehicle disclosed in Patent Document 1, when the operation lever is not operated, the state of the operation lever exceeds the set time, or when the switch attached to the operation lever is turned ON, the engine is operated. Idling operation is automatically stopped. When the operation lever is operated after the automatic engine stop, the engine is automatically started.

[0005] The construction machine disclosed in Patent Document 2 has an operation lever for commanding a hydraulic circuit to operate the construction machine, a lock position for inhibiting operation of the hydraulic circuit, and an operation of the hydraulic circuit. And a lock lever for switching between a lock release position and a lock release position. When a predetermined time has elapsed from the time when the lock lever is switched to the lock position, the operation of the engine is automatically stopped. After the automatic stop of the engine, when the lock lever is switched to the unlocked position, the hydraulic circuit becomes operable and the engine is started automatically.

Disclosure of the invention

Problems to be solved by the invention

[0006] In the work vehicle disclosed in Patent Document 1, the engine is operated by operating the operation lever. When the vehicle restarts automatically, there is a problem that the work vehicle may suddenly move in response to the operation lever. In the construction machine disclosed in Patent Document 2, when the operator performs an unlock operation of the lock lever while operating the operation lever, when the engine is restarted by the unlock operation, the hydraulic circuit simultaneously starts operating. However, there is a problem that the construction machine may be unexpectedly moved in response to the operation lever.

[0007] Accordingly, an object of the present invention is to provide a work vehicle having an idling stop control function to prevent the work vehicle from unexpectedly starting when the engine is restarted after the engine is automatically stopped by the idling stop control. Is to do.

Means for solving the problem

[0008] A work vehicle according to the present invention includes an engine, a hydraulic circuit driven by the engine, a hydraulic operating unit driven by the hydraulic circuit, and an operation of outputting an operation command signal for moving the hydraulic operating unit. The engine, the engine, the hydraulic circuit, and the operating device, the engine is stopped by an idling stop control for stopping the engine when the engine is in an idling operation state, and the idling stop control. A control device for performing engine restart control for restarting the engine later. When performing the engine restart control after stopping the engine by the idling stop control, the control device sets the hydraulic circuit to an inoperable state before restarting the engine. When the engine is inoperable, the engine is restarted in response to a predetermined trigger signal, and after the engine is restarted, when the operation command signal is not input from the operating device, the Restore circuit to operational condition.

[0009] After the engine stops, the hydraulic circuit is made inoperable, the engine is restarted thereafter, and then the hydraulic circuit is restored to an operable state. Therefore, when the engine is restarted, the hydraulic circuit is inoperable and the hydraulic operating unit cannot move, so that there is no possibility that the work machine suddenly starts moving.

In a preferred embodiment, the work machine is provided with a lock device that outputs a lock instruction signal and a lock release instruction signal for the hydraulic circuit. Then, after stopping the engine by the idling stop control, the control device restarts the engine. Before starting, the hydraulic circuit is made inoperable in response to the lock instruction signal from the lock device. Further, after the engine is restarted, when the operation command signal is not input from the operating device, the control device responds to the lock release instruction signal from the lock device and controls the hydraulic circuit. Return to an operable state. Therefore, after the engine is stopped, the engine is not restarted unless the hydraulic circuit is locked by the lock device to render the operation inoperative. Also, after the engine restarts, the hydraulic circuit will be in an operable state even if the lock is instructed to be unlocked by the lock device, as long as some operation command signal for moving the hydraulic actuator is also output. Does not return.

[0011] In a preferred embodiment, a predetermined operation command signal from the operating device is used as the predetermined trigger signal. Therefore, when a predetermined operation command signal is output from the operating device after the engine is stopped, the engine is automatically restarted.

In a preferred embodiment, the work vehicle includes a pilot pressure control device that controls a pressure of pilot pressure oil for controlling the hydraulic circuit. Then, the control device controls the pilot pressure control device to lower the pressure of the pilot pressure oil below a predetermined operation threshold, thereby disabling the hydraulic circuit, and controlling the pressure of the pilot pressure oil. The hydraulic circuit is returned to an operable state by increasing the force above the operation threshold. Further, when returning the hydraulic circuit to an operable state, the control device gradually increases the pressure of the pilot pressure oil. With this gradual pressure increase control, when the hydraulic circuit returns to an operable state, it is possible to prevent the hydraulic operating section from suddenly starting to operate.

[0013] In a preferred embodiment, the work vehicle is provided with an alarm device that outputs a warning sound or an alarm to the outside of the work vehicle. When receiving the trigger signal while the hydraulic circuit is inoperable, the control device restarts the engine after a warning sound or a warning is output from the warning device. Therefore, it is possible to inform people outside the work vehicle that the engine is restarting as much as this, and alert them to ensure safety.

The invention's effect According to the present invention, when the engine is restarted after the engine is automatically stopped by the idling stop control, the work vehicle is prevented from suddenly starting to move.

Brief Description of Drawings

FIG. 1 is a side view of a hydraulic shovel according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an overall schematic configuration of a drive control system of the hydraulic shovel according to the first embodiment.

FIG. 3 is a flowchart illustrating a processing procedure of idling stop control and engine restart control according to the first embodiment.

FIG. 4 is a view showing a pressure rise curve of a pilot source pressure immediately after the engine is restarted in the first embodiment.

FIG. 5 is a diagram showing an overall schematic configuration of a drive control system for a hydraulic shovel according to a second embodiment of the present invention.

FIG. 6 is a flowchart illustrating a processing procedure of idling stop control and engine restart control according to the second embodiment.

FIG. 7 is a diagram showing a pressure rise curve of a pilot source pressure immediately after an engine restart in a second embodiment.

Explanation of symbols

[0016] 1 Oil jEh Shobenore

2a Travel hydraulic motor

3a Hydraulic motor for turning

10 Boom cylinder

11 Arm cylinder

12 bucket cylinder

13, 14 Work implement control lever

15 Travel control lever

16 Engine

17 Hydraulic pump

18, 61 Operating valve assembly 19 Hydraulic actuator

20 Hydraulic circuit

21 Controller

21a First lever operation discriminator

21c Second lever operation determination section

21d Lock lever operation position discriminator

27 Engine control unit

28 Engine starter

33 Pilot pump

35, 36, 39, 55, 56, 59

37, 38, 40 Regulator

42, 51, 52, 53, 54, 57, 58 Potentiometer

43 Rock Reno

46 Electromagnetic proportional pressure control valve

60 Lever operation discrimination section

62a Proportional electromagnetic operation unit

BEST MODE FOR CARRYING OUT THE INVENTION

Next, specific embodiments of the work vehicle according to the present invention will be described with reference to the drawings. Although the present embodiment is an example in which the present invention is applied to a hydraulic excavator as a working vehicle, the present invention can be applied to various other working vehicles, for example, a bulldozer, a dump truck, a crane, a forklift, and the like. Needless to say.

[First Embodiment]

FIG. 1 shows a side view of a hydraulic shovel according to a first embodiment of the present invention. FIG. 2 shows an overall schematic configuration of the drive control system of the excavator.

As shown in FIG. 1, the hydraulic excavator 1 of the present embodiment includes a lower traveling body 2 having a traveling device 2b driven by a traveling hydraulic motor 2a, and a swing driven by a swing hydraulic motor 3a. Device 3 and an upper swing provided on the lower traveling body 2 via the swing device 3 The vehicle includes a body 4, a work implement 5 attached to a central position in the front of the upper swing body 4, and a driver's cab 6 provided at a front left position of the upper swing body 4. Here, the working machine 5 includes a boom 7 that is swingably connected to the upper swing body 4, an arm 8 that is swingably connected to the boom 7, and a packet that is swingably connected to the arm 8. Has 9 Work implement 5 further includes hydraulic cylinders for moving boom 7, arm 8 and packet 9, ie, boom cylinder 10, arm cylinder 11 and bucket cylinder 12. Also, on both sides of a driver's seat (not shown) in the operator's cab 6, work implement operation levers 13, 14 for operating the swinging operation of the upper revolving superstructure 4 and the bending and stretching and lifting and lowering of the work implement 5 (see FIG. 2). A pair of traveling operation levers 15 and 15 (see FIG. 2) for operating the traveling operation of the lower traveling unit 2 are disposed in front of the driver's seat.

As shown in FIG. 2, the drive control system of the excavator 1 has a hydraulic circuit 20 in which hydraulic oil discharged from a hydraulic pump 17 driven by an engine 16 is operated by an operating valve. It is supplied to the hydraulic operating section 19 through the assembly 18. Here, the hydraulic operating section 19 is a block diagram of various hydraulic actuators such as the boom cylinder 10, the arm cylinder 11, the bucket cylinder 12, the traveling hydraulic motor 2a, and the turning hydraulic motor 3a. It was done. The operating valve assembly 18 is an assembly of hydraulic pilot operated directional control valves 34,..., 34 corresponding to the hydraulic actuators. By operating the hydraulic circuit 20, the bending and stretching and raising / lowering operations of the work implement 5, the turning operation of the upper revolving unit 4, and the traveling operation of the lower traveling unit 2 are performed. The drive control system has a controller 21. The controller 21 is, for example, a computer, and executes a predetermined control program (not shown) to execute idling stop control, engine restart control, and the like. A central processing unit for performing arithmetic processing for the control, a storage device for storing the control program, various tables and setting condition data used for the arithmetic processing, and input / output of various signals described below. It has an input / output device.

The engine 16 is, for example, a diesel engine. The engine 16 is provided with a fuel injection pump 22 and a governor 23. The governor 23 has a fuel control lever 23a driven by a governor drive motor 24. Fuel control lever 23a Is detected by the potentiometer 25, and the detection signal is input to the controller 21. Further, a fuel dial (not shown) is provided to set the throttle position (engine speed) of the engine 16. A throttle signal (set speed signal) from a potentiometer (not shown) attached to the fuel dial is provided. Is input to the controller 21. The actual rotation speed of the engine 16 is detected by a rotation speed sensor 26, and the detection signal is also input to the controller 21.

In the present embodiment, an engine control device 27 mainly includes a controller 21, a governor 23, a governor drive motor 24, a potentiometer 25, and a fuel dial. In the engine control device 27, the controller 21 determines a difference between a throttle signal (set rotation speed signal) input from the fuel dial and an actual rotation speed signal of the engine 16 detected by the rotation speed sensor 26. A drive signal having a voltage level that satisfies a predetermined functional relationship with respect to the difference signal is generated, and the governor drive motor 24 is driven based on the drive signal.

Here, as an example, if the fuel dial is set to the maximum position (FULL position), the throttle signal output from the potentiometer attached to the fuel dial indicates the maximum set rotation speed. The controller 21 applies a motor drive signal corresponding to the maximum set number of revolutions to the governor drive motor 24. As a result, the governor drive motor 24 operates the fuel control lever 23a so that the highest speed regulation line is set, and as a result, the output horsepower and the engine speed of the engine 16 are automatically set. As another example, assuming that a motor drive signal corresponding to an engine stop command is applied from the controller 21 to the governor drive motor 24, the governor drive motor 24 operates so that the fuel injection by the fuel injection pump 22 becomes non-injection. Then, the fuel control lever 23a is operated, whereby the operation of the engine 16 is stopped.

Further, the engine 16 is provided with an engine starting device 28 for starting the engine 16. The engine starter 28 also includes a starter 29, a starter switch 30, a battery 31, a battery relay 32, and wiring for connecting these devices. In this engine starter 28, the operator operates the starter switch 30 When this is set to the start position, the start signal flows to the starter 29, and the electric power from the notch 31 is supplied to the starter 29 via the battery relay 32, whereby the starter 29 drives the engine 16 to drive the engine 16 Is started. Similarly, when a start signal flows from the controller 21 to the starter 29, the starter 29 drives the engine 16 to start the engine 16! /.

The hydraulic pump 17 is, for example, a variable displacement hydraulic pump. The hydraulic pump 17 includes a pilot pump (pilot pressure oil generating device) 33 that is driven by the engine 16 and discharges pilot pressure oil. It is installed continuously. On the other hand, as described above, the operating valve assembly 18 includes various hydraulic actuators (the traveling hydraulic motor 2 a, the swing hydraulic motor 3 a, the boom cylinder 10, the arm cylinder 11, and the bucket) included in the hydraulic operating section 19. A set of hydraulic pilot operated directional control valves 34,. By supplying various pilot pressure oils output from pressure reducing valves 37, 38, and 40, which will be described later, to the directional control valves,, the work implement 5, the upper revolving unit 4, and the lower traveling unit. Various oil path switching operations for moving the motor 2 are performed.

[0026] The work implement operation levers 13, 14 are provided with pressure reducing valves (pilot pressure oil pressure output devices) 37, 38 via operation units 35, 36 that output various operation commands corresponding to various lever operations. It is attached. Similarly, the traveling operation levers 15 and 15 are provided with a pressure reducing valve (pilot pressure oil pressure output device) 40 via an operation unit 39 that outputs various operation commands corresponding to various lever operations. The pilot pressure oil discharged from the pilot pump 33 is supplied to the pressure reducing valves 37, 38, and 40 via an electromagnetic proportional pressure control valve 46 described later. The pressure-reducing valves 37, 38, and 40 regulate the pressure of the supplied pilot pressure oil based on various operation commands from the operation units 35, 36, 15, and 15, and use the regulated pilot pressure oil to operate the valve assembly. Output for 18 mm. The various pilot pressure oils output from the pressure reducing valves 37, 38, and 40 are input to the corresponding pilot pressure oil input ports in the operation valve assembly 18, whereby the various oil path switching operations described above are performed. Done. As a result, the turning operation of the upper rotating body 4 and the bending and stretching and raising / lowering operations of the working machine 5 are performed by operating the work implement operating levers 13 and 14, and the lower traveling body is operated by operating the travel operating levers 15 and 15. The traveling operation of 2 will be performed. [0027] In addition, operation signals indicating the respective operating states of the work implement operation levers 13, 14 and the travel operation levers 15, 15 are transmitted to hydraulic switches 41, ..., 41 attached to the pressure reducing valves 37, 38, 40. Is input to the controller 21 via the. In the present embodiment, the operation signals input to the controller 21 include, for example, the following twelve types.

(1) Right turning operation signal corresponding to right turning operation of upper revolving superstructure 4

(2) Left turning operation signal corresponding to left turning operation of upper revolving unit 4

(3) Boom raising operation signal corresponding to the raising operation of boom 7

(4) Boom lowering operation signal corresponding to the lowering operation of boom 7

(5) Arm dump operation signal corresponding to the operation of sending arm 8 forward

(6) Arm excavation operation signal corresponding to the operation of pulling arm 8 forward

(7) Packet dump operation signal corresponding to the operation of sending packet 9 forward

(8) Packet excavation operation signal corresponding to the operation of pulling packet 9 forward

(9) Right forward traveling operation signal corresponding to the right forward traveling operation of the lower traveling unit 2

(10) Right reverse traveling operation signal corresponding to right reverse traveling operation of lower traveling unit 2

(11) Left forward traveling operation signal corresponding to left forward traveling operation of lower traveling unit 2

(12) Left reverse traveling operation signal corresponding to left reverse traveling operation of lower traveling unit 2

[0028] The controller 21 has, as one function, a first lever operation determination unit 21a. The first lever operation determination unit 21a determines which lever operation is being performed based on the input operation signals (1) and (12). While the engine 16 is operating, the controller 21 uses the first lever operation determination unit 21a to determine whether or not there is any lever operation. The controller 21 has a timer 21b that counts a predetermined time length as another function. The length of time counted by the timer 21b can be set by the operator from a control panel (not shown) arranged in the cab. In the idling stop control, the controller 21 counts the predetermined time length by the timer 21b while the engine 16 is in the idling operation state.

[0029] The operation unit 35 coupled to the work implement operation lever 13 indicates whether or not a specific lever operation, such as a boom raising operation, of various lever operations of the work implement operation lever 13 is performed. A potentiometer 42 for outputting an electric signal, that is, a boom raising operation signal, is provided. The boom raising operation signal from the potentiometer 42 is input to the controller 21. The controller 21 has, as another function, a second lever operation determining section 21c, which determines whether or not the boom raising operation is performed based on a boom raising operation signal input from the potentiometer 42. Is determined. In the engine restart control after the engine 16 is stopped by the idling stop control, the controller 21 determines the presence or absence of the boom raising operation by the second lever operation determination unit 21c. In the present embodiment, the force in which “boom raising operation” is employed as the specific lever operation. This is only an example, and a lever operation other than “boom raising operation” may be employed.

[0030] In the cab 6, a lock lever 43 for switching between a lock position where the operation of the hydraulic circuit 20 is prohibited and a lock release position where the operation of the hydraulic circuit 20 is permitted is provided. When the lock lever 43 is in the lock release position, an ON signal (lock release position signal) from the limit switch 44 pushed by the lock lever 43 is input to the 1S controller 21. The controller 21 further has a lock lever operation position determination unit 21d as another function. The lock lever operation position determination unit 21d determines whether the lock lever 44 is in the lock position or the unlock position based on the lock release position signal input from the limit switch 44. Is determined. In the engine restart control after the engine 16 is stopped by the idling stop control, the controller 21 determines the position of the lock lever 44 by the lock lever operation position determination unit 21d.

[0031] An electromagnetic proportional pressure control valve (pressure control device) 46 is provided in a pilot pressure oil supply pipe line 45 connecting the above-mentioned pilot pump 33 and the pressure reducing valves 37, 38, 40. The pressure of the pilot pressure oil supplied from the pilot pump 33 to each of the pressure reducing valves 37, 38, and 40 is also controlled in proportion to the magnitude of the control current input to the electromagnetic proportional pressure control valve 46.

[0032] The pressure sensor 47 detects the discharge pressure of the hydraulic pump 17. The pressure detection signal from the pressure sensor 47 is input to the controller 21. Further, the pressure sensor 48 detects the pressure of the pilot pressure oil supplied to the pressure reducing valves 37, 38, 40 via the electromagnetic proportional pressure control valve 46. A pressure detection signal from the pressure sensor 48 is input to the controller 21 and is output to a pilot It is used as a feedback signal in controlling the source pressure.

Next, a processing procedure of the idling stop control and the engine restart control performed by the controller 21 executing the control program will be described below with reference to a flowchart of FIG. In FIG. 3, the control in steps S1 to S4 corresponds to idling stop control, and the control in steps S5 to S11 corresponds to engine restart control.

[0034] As shown in FIG. 3, in step S1, the controller 21 determines whether or not the engine 16 is in an idling operation state. That is, when any one of the operation signals (1) and (12) is input to the controller 21, that is, when one of the work implement 5, the upper revolving unit 4, and the lower traveling unit 2 operates, If so, the controller 21 determines that the engine 16 is not in the idling operation state, and continues the operation of the engine 16 (step S2). On the other hand, when neither! / Nor the deviation of the operation signals (1) and (12) is input to the controller 21, that is, all of the work implement 5, the upper revolving unit 4, and the lower traveling unit 2 When not operating, it is determined that the engine 16 is in the idling operation state.

[0035] In step S1, when it is determined that the engine 16 has entered the idling operation state, the controller 21 starts counting for a predetermined time (for example, about several tens of seconds) by the timer 21b. It is determined whether or not has been continued for the predetermined time (S3). As a result, when the duration of the idling operation state reaches the predetermined time, the controller 21 transmits a motor drive signal corresponding to the engine stop command to the governor drive motor 24 to stop the engine 16. (S4).

[0036] After the engine 16 is stopped in step S4, the controller 21 uses the lock lever operation position determining unit 21d to determine whether the lock release position signal is input from the limit switch 44 or not. It is determined whether the position is at the lock position or the unlock position (S5). When it is determined in step S5 that the position of the lock lever 43 is at the unlock position, the controller 21 waits. On the other hand, if it is determined in step S5 that the position of the lock lever 43 is at the lock position, the controller 21 determines whether the pilot pressure supplied to the pressure reducing valves 37, 38, 40 through the electromagnetic proportional pressure control valve 46 is satisfied. Oil pressure (hereinafter referred to as “pilot source pressure”) (Pc) Minimum oil pressure at which various oil path switching operations can be performed by the operation valve assembly 18 (hereinafter referred to as “operation threshold value” of the operation valve assembly 18) ( Pt) The control current is output to the electromagnetic proportional pressure control valve 46 so that the predetermined value (Pa) becomes smaller than the predetermined value (Pa) (S6). As a result, even when the operating levers 13, 14, 15 are operated, the work implement 5, the upper swing body 4, and the lower traveling body 2 are not driven. In other words, the operation of the hydraulic circuit 20 is prohibited. However, the value (Pa) of the pilot source pressure (Pc) at this time is determined by the minimum hydraulic pressure (hereinafter, hydraulic pressure) that can operate the hydraulic switches 41, ..., 41 connected to the outputs of the pressure reducing valves 37, 38, 40. (Referred to as the "operation threshold value" of the switches 41, 41), (Ps), and therefore, various operations performed on the operating levers 13, 14, 1 and 5 are performed by the hydraulic switches 41, Are detected by the controller 41 and recognized by the controller 21.

Only when the operation of the hydraulic circuit 20 is prohibited in response to the lock position of the lock lever 43 in steps S5 and S6 described above, control proceeds to step S7. In step S7, the controller 21 performs a specific lever operation, that is, a lever operation related to the boom raising operation, based on the boom raising operation signal from the potentiometer 42 by the second lever operation determination 21c. It is determined whether or not there is (S7). If it is determined in step S7 that the specific lever operation is being performed, the controller 21 transmits a start signal to the starter 29 to start the engine 16 (S8). As described above, when the engine 16 is restarted in response to the specific lever operation, the operation of the hydraulic circuit 20 is already prohibited by the above-described step S6 (Pc <Pt). Accordingly, the corresponding oil passage switching operation is not performed by the operation valve assembly 18. Therefore, there is no possibility that the excavator 1 may suddenly start when the engine is restarted. At this time, since the pilot source pressure (Pc) is higher than the operation threshold (Ps) of the hydraulic switches 41,..., 41 (Pc = Pa> Ps), the controller 21 The portion 21a can determine the presence or absence of various lever operations after the engine is started.

[0038] After restarting the engine 16 in step S8, the controller 21 uses the first lever operation determination unit 21a to output the (1)-(12) from the hydraulic switches 41,. Based on the presence or absence of the operation signal, it is determined whether or not all the operation levers 13, 14, 15, and 15 are in the -Eutral position (no operation of the lever for moving the excavator 1 is performed). It is determined (S9). In step S9, any of the operation levers 13, 14, 15, and 15 is not in the -Eutral position (some lever operation for moving the excavator 1 is performed. ), The controller 21 waits. On the other hand, if it is determined in step S9 that all of the operation levers 13, 14, 15, and 15 are at the -Eutral position, the controller 21 uses the lock lever operation position determination unit 21d to perform the limit switch 4 operation. It is determined whether the lock lever 43 is at the lock position or the unlock position based on the presence or absence of the input of the unlock position signal from 4 (S10). If it is determined in step S10 that the lock lever 43 is at the lock position, the control by the controller 21 returns to step S9. On the other hand, if it is determined in step S10 that the lock lever 43 is at the unlock position, the controller 21 outputs a control current to the electromagnetic proportional pressure control valve 46 (SI 1), The pressure (Pc) is increased in a curve as shown in FIG. As a result, as shown in FIG. 4, the pilot source pressure (Pc) rapidly rises from the predetermined value (Pa) to the operation threshold (Pt) of the operation valve assembly 18, and thereafter, the operation threshold (Pc) t) Gradually increase gradually to the maximum set pressure value (Pe) higher than. The operation of increasing the pilot source pressure (Pc) is performed in a state where the rotation speed of the engine 16 is equal to or higher than a certain rotation speed and the discharge pressure of the pilot pump 33 has risen to a necessary and sufficient level. With such an increase in the pilot pressure (Pc), the state of the operation valve assembly 18 shifts to a state in which the oil passage switching operation can be performed (that is, the state of the hydraulic circuit 20 becomes operable). Transition) . Therefore, when the operation levers 13, 14, 15, and 15 are operated, the operation of the excavator 1 (the hydraulic operating section 19) starts.

In this way, after the engine restarts, the controller 21 locks only when all the operating levers are in the -Eutral position (that is, when no lever operation is performed to move the excavator 1). In response to the unlocking of the lever 43, the pilot pressure (Pc) is increased to the maximum set pressure value (Pe) higher than the operation threshold value (Pt) of the operation valve assembly 18 and the hydraulic circuit 20 is activated. Move to a possible state. Therefore, when the engine 16 restarts in response to a specific lever operation, the hydraulic excavator 1 (the hydraulic operating section 19) does not suddenly start moving. In addition, since the operating threshold (Pt) force of the pilot source pressure (Pc) is gradually increased gradually to the maximum set pressure value, even if any lever operation is performed immediately after the lock is released, the hydraulic excavator 1 ( The hydraulic operating section 19) starts operating at a low speed, and a sharp high-speed operation at the start of the operation is avoided. [Second Embodiment]

FIG. 5 shows an overall schematic configuration of a drive control system for a hydraulic shovel according to a second embodiment of the present invention. Note that, in the present embodiment, the same or similar elements as those in the first embodiment are denoted by the same reference numerals, and redundant description thereof will be omitted. The different parts will be mainly described. The basic configuration of the excavator is as described above with reference to FIG.

In the present embodiment, the operating units 55 and 56 use the potentiometers 51, 52, 53 and 54 to transmit various operation commands corresponding to various lever operations of the work implement operation levers 13 and 14, using electric signals (operations). Signal), and outputs it to the controller. The operation unit 59 converts various operation commands corresponding to various lever operations of the traveling operation levers 15 and 15 into electric signals (operation signals) by potentiometers 57 and 58 and outputs the signals to the controller 21. The controller 21 has a lever operation determination unit 60, which determines whether or not a force is exerted for performing various lever operations based on various input operation signals. The types of operation signals input to the controller 21 include, for example, the above-described (1) and (12) operation signals.

The operation valve assembly 61 controls the supply of the hydraulic oil discharged from the hydraulic pump 17 to the hydraulic operating section 19. An operating valve assembly 61 is provided corresponding to each hydraulic actuator (hydraulic motor 2a, swing hydraulic motor 3a, boom cylinder 10, arm cylinder 11, bucket cylinder 12) of the hydraulic operating section 19. It is an aggregate of a plurality of electromagnetic hydraulic pilot operated directional control valves 62. Each electromagnetic and hydraulic pilot operated directional control valve 62 includes a proportional electromagnetic operating part 62a and a hydraulic pilot operating part 62b. When any of the above-described potentiometers 51, 52, 53, 54, 57, and 58 is operated by the S controller 21, the controller 21 generates an operation current based on the input operation signal. , And output to the proportional electromagnetic operating section 62a of the corresponding directional control valve 62. In each operating valve 62, the proportional electromagnetic operating section 62a regulates the pilot pressure oil supplied from the pilot pump 33 in proportion to the operating current from the controller 21, and the regulated pilot oil is According to the pilot pressure oil output to the hydraulic pilot operation unit 62b and output to the hydraulic pilot operation unit 62b, a predetermined oil path switching operation for controlling the corresponding hydraulic actuator is performed. Next, a processing procedure of the idling stop control and the engine restart control performed by the controller 21 will be described with reference to a flowchart of FIG. In FIG. 6, steps R1 to R4 correspond to idling stop control, and steps R5 to R11 correspond to engine restart control.

As shown in FIG. 6, in the step, the controller 21 determines whether or not the engine 16 is in the idling operation state based on the presence or absence of the (1)-(12) various operation signals. . When any one of the various operation signals (1) and (12) is input, the controller 21 determines that the engine 16 is not in the idling operation state, and continues the operation of the engine 16 in step R2. On the other hand, when none of the various operation signals (1) and (12) is input, the controller 21 determines that the engine 16 is in the idling operation state.

In step R1, when the engine 16 enters the idling operation state, the controller 21 starts powering for a predetermined time (for example, about several tens of seconds) by the timer 21b in step R3. It is determined whether the idling operation state has continued for a predetermined time. If the count value of the timer 21b has not exceeded the predetermined time, the controller 21 continues the operation of the engine 16 (R2). On the other hand, when the count value of the timer 21b reaches the predetermined time, the controller 21 transmits a motor drive signal corresponding to the engine stop command to the governor drive motor 24 in step R4, and stops the engine 16.

After the engine 16 is stopped in step R4, the controller 21 controls the lock lever 43 based on the input of the lock release position signal from the limit switch 44 by the lock lever operation position determination unit 21d. It is determined whether is in the lock position or the unlock position (R5). If it is determined in step R5 that the lock lever 43 is at the unlock position, the controller 21 waits. On the other hand, if it is determined in step R5 that the lock lever 43 is in the lock position, the controller 21 sets the value of the control current output to the electromagnetic proportional pressure control valve 46 to zero (R6). In step R6, the pressure of the pilot pressure oil (hereinafter referred to as “pilot source pressure”) (Pc) supplied from the pilot pump 33 to each electromagnetic and hydraulic pilot operated directional control valve 62 through the electromagnetic proportional pressure control valve 46 is reduced. Ze As a result, the hydraulic circuit 20 cannot drive any of the hydraulic actuators of the hydraulic operating section 19.

[0047] Thereafter, the controller 21 determines whether any of various lever operations for moving the excavator 1 is performed based on the presence or absence of a potentiometer 51, 52, 53, 54, 57, 58 force operation signal. It is determined whether or not the operation has been performed (R7). If it is determined in step R7 that any lever operation has been performed, the controller 21 transmits a start signal to the starter 29 to start the engine 16 (R8). As described above, after the engine 16 is automatically stopped by the idling stop control, if any operation is performed on the work implement operation levers 13, 14 or the travel operation levers 15, 15, the engine is automatically restarted. However, at this time, the pilot source pressure (Pc) is already controlled to zero by the above-described step R6, so that the oil passage switching operation of the operation valve assembly 61 cannot be performed. Therefore, even if the engine 16 is restarted, there is no possibility that the hydraulic shovel 1 (the hydraulic operating section 19) starts to move suddenly.

[0048] After the engine 16 is restarted in step R8, the controller 21 receives the operation signals (1) and (12) from the potentiometers 51, 52, 53, 54, 57, and 58. Based on the presence / absence, whether all of the work implement operation levers 13 and 14 and the travel operation levers 15 and 15 are in the -Eutral position (that is, no lever operation for moving the excavator 1 is performed) IJ 另 IJ (R9). If it is determined in step R9 that any of the operating levers 13, 14, 15, and 15 is not at the -Eutral position (that is, some lever operation for moving the excavator 1 is being performed), the controller 21 waits. At this time, as described above, since the pilot source pressure (Pc) is controlled to zero, the excavator 1 remains stationary regardless of any lever operation. In step R9, if it is determined that all the operation levers 13, 14, 15, and 15 are in the -Eutral position, the controller 21 determines whether the lock release position signal is input from the limit switch 44 or not. The lever operation position determination section 21d determines whether the lock lever 43 is at the lock position or the unlock position (R10). If it is determined in step RIO that the lock lever 43 is at the lock position, the control by the controller 21 returns to step R9. On the other hand, in step R10, it is determined that the lock lever 43 is in the unlock position. If separated, the controller 21 outputs a control current to the electromagnetic proportional pressure control valve 46 so that the pilot source pressure (Pc) increases along the curve shown in FIG. 7 (R11). As a result, as shown in FIG. 7, the pilot pressure (Pc) is reduced from zero to the minimum oil pressure at which the oil passage switching operation of the operation valve assembly 18 can be performed (hereinafter referred to as the “operation threshold” of the operation valve assembly 18). (Pt) in a short time, and then gradually increase to a maximum set pressure value (P e) higher than its operating threshold (Pt). The operation of increasing the pilot source pressure is performed in a state where the number of revolutions of the engine 16 is equal to or higher than a certain number of revolutions and the discharge pressure of the pilot pump has risen to a necessary and sufficient level. As a result of the rise of the pilot base pressure (Pc), the oil path switching operation of the operation valve assembly 61 can be performed, and therefore, the hydraulic excavator 1 (the hydraulic operating section 19) can move.

[0049] As described above, after the engine is restarted, all the operation levers 13, 14, 15, and 15 are in the -Eutral position operation (that is, the lever operation for moving the excavator 1 is not performed at all). Only in this case, the controller 21 changes the hydraulic circuit 20 from the inoperable state to the operable state in response to the unlocking operation of the lock lever 43. Therefore, when the hydraulic circuit 20 becomes operable by the unlocking operation, there is no possibility that the hydraulic excavator 1 (the hydraulic pressure operating section 19) starts to move suddenly. In addition, the pilot base pressure (Pc) also gradually increases the operation threshold value (Pt) force to the maximum set pressure value (Pe), so that no matter what lever operation is performed immediately after unlocking, the hydraulic pressure The excavator 1 (the hydraulic operating section 19) starts operating at a low speed, and a sharp high-speed operation at the start of the operation is avoided. No matter how the operating levers 13, 14, 15, and 15 are operated, the hydraulic operating section 19 starts operating at a low speed, and a rapid high-speed operation at the start of the operation is avoided.

As a modified example, in the first embodiment described above, between steps S6 and S7 shown in the flowchart of FIG. 3, or in the second embodiment, the flowchart of FIG. Between the step R6 and the step R7 shown in the above, a step of checking whether or not the operator has sounded the horn of the hydraulic shovel 1 (not shown) is performed, and the horn sounds in advance. Otherwise, the engine 16 may be controlled so as not to be restarted. Alternatively, or by automatically sounding a beep before restarting the engine, or by using other appropriate alarming methods, people who are outside the excavator 1 or to the excavator 1 The operator on board may be automatically notified that the engine restart operation will be performed. According to these modifications, a warning or an alarm is output inside and outside the excavator 1 immediately before restarting the engine, so that people near the excavator 1 or an operator who is on the excavator 1 can be notified. It can call attention to safety in preparation for the engine restart.

Although the embodiment of the present invention has been described above, this embodiment is merely an example for describing the present invention, and is not intended to limit the scope of the present invention to only this embodiment. The present invention can be implemented in various other modes without departing from the gist thereof.

Claims

The scope of the claims

[1] An engine (17), a hydraulic circuit (20) driven by the engine, a hydraulic operating unit (19) driven by the hydraulic circuit, and an operation command signal for moving the hydraulic operating unit An operation device (13, 14, 15) for outputting, an idling stop control connected to the engine, the hydraulic circuit, and the operation device for stopping the engine when the engine is in an idling operation state; and the idling stop. A control device (21) for performing an engine restart control for restarting the engine after the engine is stopped by control;

When the control device performs the engine restart control after stopping the engine by the idling stop control,

Before the engine is restarted, the hydraulic circuit is made inoperable (S6, R6) .When the hydraulic circuit is inoperable, the engine is restarted in response to a predetermined trigger signal. (S7, S8, R7, R8),

After the engine is restarted, when the operation command signal is not input from the operation device, the hydraulic circuit is returned to an operable state (S9, Sl1, R9, R11). Working vehicle.

[2] A lock device that outputs a lock instruction signal and an unlock instruction signal for the hydraulic circuit

(43) is further provided,

The control device includes:

After stopping the engine by the idling stop control and before restarting the engine, the hydraulic circuit is made inoperable in response to the lock instruction signal from the lock device (43) (S5 , S6, R5, R6),

After the engine is restarted, the operation command signal is input from the operation device, and the operation of the hydraulic circuit is performed in response to the lock release instruction signal from the lock device (43). 2. The work vehicle according to claim 1, wherein the work vehicle is returned to an operable state (S9, S10, Sl1, R9, RIO, R11).

3. The work vehicle according to claim 1, wherein the predetermined trigger signal is a predetermined operation command signal from the operation device. [4] a pilot pressure control device (46) for controlling the pressure of pilot pressure oil for controlling the hydraulic circuit,

The control device controls the pilot pressure control device (46) to make the hydraulic circuit inoperable by lowering the pressure of the pilot pressure oil below a predetermined operation threshold, and to reduce the pressure of the pilot pressure oil. 2. The work vehicle according to claim 1, wherein the hydraulic circuit is returned to an operable state by increasing the operation threshold.

5. The work vehicle according to claim 4, wherein the control device gradually increases the pressure of the pilot pressure oil when returning the hydraulic circuit to an operable state.

[6] further comprising an alarm device for outputting a warning sound or an alarm,

When receiving the trigger signal while the hydraulic circuit is inoperable, the control device restarts the engine after the alarm device outputs the audible alarm or the alarm. The work vehicle according to claim 1, wherein

[7] An engine (17), a hydraulic circuit (20) driven by the engine, a hydraulic operating unit (19) driven by the hydraulic circuit, and an operation command signal for moving the hydraulic operating unit A control method for restarting the engine after the engine is stopped by idling stop control in a working vehicle provided with an operating device (13, 14, 15) for outputting an output,

Disabling the hydraulic circuit before restarting the engine (S6, R6);

Restarting the engine in response to a predetermined trigger signal when the hydraulic circuit is inoperable (S7, S8, R7, R8);

(S9, Sll, R9, R11) returning the hydraulic circuit to an operable state when no operation command signal has been input after the engine has been restarted.

An engine restart control method comprising: