JP7193419B2 - construction machinery - Google Patents

Description

The present invention relates to a construction machine such as a hydraulic excavator having a machine control function for controlling a working device so as not to excavate the ground beyond a target surface, and more particularly to a construction machine having a so-called auto-idle function.

For example, there is known a construction machine equipped with an auto-idling function that reduces the engine speed to the idle speed when no operation is performed (see Patent Document 1, etc.).

Japanese Patent Application Laid-Open No. 2010-101068

In recent years, there has been an increasing demand for construction machinery equipped with a machine control function that controls a working device so as not to excavate the ground beyond a target surface. Machine control is performed based on response characteristic data obtained under a set engine speed through metering learning. In the metering learning, the operation lever is actually operated to drive the working device, and the operating speed of the actuator at that time is measured. This is repeated by changing the operation target and the lever operation amount, and the response characteristics (for example, the relationship between the operation speed and the lever operation amount in each actuator) are stored in the controller of the construction machine. Even if the model is the same, the response characteristics of construction machinery differ due to individual differences in parts such as actuators, control valves, and hydraulic pumps.

In construction machinery with a machine control function, the auto idle function is generally disabled when the function is enabled (when the on/off switch for the function is turned on). The machine control function assumes the engine speed at the time of metering learning, and if it is executed at an engine speed lower than the engine speed at which metering learning was performed, an error will occur in the control of the work equipment and excavation will occur beyond the target plane. This is because there is a possibility that However, from the viewpoint of energy saving, it is desired that the auto idle function is utilized even when the machine control function is enabled.

SUMMARY OF THE INVENTION An object of the present invention is to provide a construction machine capable of achieving both a machine control function and an auto idle function.

In order to achieve the above object, the present invention provides a vehicle body, a working device attached to the vehicle body, a plurality of hydraulic actuators for driving the working device, a plurality of attitude sensors for detecting the posture of the working device, a hydraulic pump that discharges pressure oil for driving the plurality of hydraulic actuators; a pilot pump; a control valve unit that controls the flow of pressure oil supplied from the hydraulic pump to the plurality of hydraulic actuators; a plurality of operating lever devices for outputting pilot pressure for driving the control valve unit using the discharge pressure as a source pressure; a machine control solenoid valve unit provided between the plurality of operating lever devices and the control valve unit; an auto-idle switch for switching between enabling and disabling the function; a machine control switch for switching between enabling and disabling the machine control function; a monitor for displaying information about the vehicle; a controller that controls the machine control solenoid valve unit to limit the operation of the work device so that the ground is not excavated beyond a target surface, wherein the controller controls the machine control switch and the auto idle. If it is determined based on the signal from the switch that both the machine control function and the auto-idle function are valid, and the distance L between the toe of the bucket and the target surface is equal to or less than the set distance L1, the auto-idle function is activated. is automatically disabled, and the auto-idle function is enabled when the distance L between the toe of the bucket and the target surface is greater than the set distance L1 , and the controller controls the machine control function and the auto-idle function. When it is determined that both settings are effective, the idling rotation speed, which is the set rotation speed during auto idling, is set larger as the distance L becomes smaller in a region where the distance L is greater than the set distance L1 . do.
Further, the present invention includes a vehicle body, a work device attached to the vehicle body, a plurality of hydraulic actuators for driving the work device, a plurality of attitude sensors for detecting the posture of the work device, and the plurality of hydraulic actuators. A hydraulic pump that discharges driving pressure oil, a pilot pump, a control valve unit that controls the flow of pressure oil supplied from the hydraulic pump to the plurality of hydraulic actuators, and a discharge pressure of the pilot pump as a source pressure. a plurality of operating lever devices for outputting pilot pressure for driving the control valve units; a machine control solenoid valve unit provided between the plurality of operating lever devices and the control valve units; and enabling or disabling an auto idle function. An auto idle switch for switching settings, a machine control switch for switching between enabling and disabling settings for machine control functions, a monitor for displaying information on the vehicle body, and the machine control electromagnetic valve unit based on signals from the plurality of attitude sensors. a controller for limiting the operation of the work device so that the ground is not excavated beyond the target surface, and at least one of a sensor for measuring the temperature of hydraulic oil and a sensor for measuring the temperature of engine cooling water. In the construction machine equipped with a sensor, the controller determines that the settings of both the machine control function and the auto-idle function are valid based on signals from the machine control switch and the auto-idle switch. When the distance L between the toe of the bucket and the target surface is equal to or less than the set distance L1, the auto idle function is automatically disabled, and when the distance L between the toe of the bucket and the target surface is greater than the set distance L1, the auto idle function is disabled. When the idle function is enabled and the controller determines that the settings of both the machine control function and the auto idle function are valid, the lower the temperature measured by the temperature sensor, the larger the set distance L1 is set. characterized by

According to the present invention, both the machine control function and the auto idle function can be achieved.

1 is a perspective view showing the appearance of a construction machine according to a first embodiment of the present invention; FIG. FIG. 2 is a diagram showing a hydraulic system provided in the construction machine shown in FIG. 1 together with a controller and the like; A block diagram of a controller provided in the construction machine shown in FIG. Schematic diagram used to explain the functions of the controller provided in the construction machine shown in FIG. Schematic diagram used to explain the functions of the controller provided in the construction machine shown in FIG. FIG. 2 is a flow chart showing the procedure of automatic ON/OFF control of the auto idle function by the controller provided in the construction machine shown in FIG. 1; FIG. 5 is a flow chart showing the procedure of automatic on/off control of the auto idle function by the controller provided in the construction machine according to the second embodiment of the present invention; FIG. FIG. 4 is a diagram schematically showing an example of reference data that defines the relationship between the distance L from the target surface to the tip of the bucket and the target rotation speed of the engine; FIG. 4 is a diagram schematically showing another example of reference data that defines the relationship between the distance L from the target plane to the tip of the bucket and the target rotational speed of the engine; FIG. 10 is a flow chart showing a procedure of automatic ON/OFF control of an auto idle function by a controller provided in a construction machine according to a third embodiment of the present invention; FIG. A diagram schematically showing an example of reference data that defines the relationship between hydraulic oil temperature and set distance L1. A diagram schematically showing an example of reference data defining the relationship between the engine coolant temperature and the set distance L1.

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

(First embodiment)
－Construction Machinery－
FIG. 1 is a perspective view showing the appearance of a construction machine according to a first embodiment of the invention. In this embodiment, a hydraulic excavator equipped with a bucket 23 as an attachment at the tip of the working device will be described as an example of a construction machine. However, the present invention can also be applied to other types of construction machines such as hydraulic excavators and bulldozers equipped with attachments other than buckets. In the specification of the present application, the front of the operator's cab 14 (upper left side in FIG. 1) is defined as the front of the revolving structure of the construction machine.

The construction machine shown in the figure includes a vehicle body 10 and a working device 20 . The vehicle body 10 includes a traveling body 11 and a revolving body 12 .

In this embodiment, the traveling body 11 includes left and right crawlers (traveling devices) 13 having crawler belts, and travels by driving the left and right crawlers 13 with left and right travel motors (not shown), respectively. A hydraulic motor, for example, is used as the traveling motor.

The revolving body 12 is provided above the traveling body 11 so as to be able to revolve via a revolving device (not shown). An operator's cab 14 is provided in the front part of the revolving body 12 (the left front part in this embodiment). A power room 15 containing an engine, a hydraulic system, etc. is mounted on the rear side of the operator's cab 14 in the revolving body 12 , and a counterweight 16 for balancing the weight with the working device 20 is mounted on the rear end. A turning device that connects the turning body 12 to the traveling body 11 includes a turning motor 34 ( FIG. 2 ), and the turning motor 34 drives the turning body 12 to turn relative to the traveling body 11 . A hydraulic motor is used for the turning motor 34 .

The working device 20 is an articulated working arm for performing work such as excavating earth and sand, and is attached to the front portion of the revolving body 12 (on the right side of the operator's cab 14 in this embodiment). This work device 20 is configured including a boom 21 , an arm 22 and a bucket 23 . The boom 21 is connected to a base frame of the revolving body 12 called a revolving frame by a pin (not shown) extending in the left and right direction, and rotates up and down with respect to the revolving body 12 as the boom cylinder 31 expands and contracts. Both ends of the boom cylinder 31 are rotatably connected to the boom 21 and the revolving body 12 via pins (not shown) extending to the left and right. The arm 22 is connected to the tip of the boom 21 by a pin (not shown) extending left and right, and rotates back and forth with respect to the boom 21 as the arm cylinder 32 expands and contracts. Both ends of the arm cylinder 32 are rotatably connected to the arm 22 and the boom 21 via pins (not shown) extending in the left and right direction. The bucket 23 is connected to the tip of the arm 22 by a pin (not shown) extending horizontally to the left and right, and rotates with respect to the arm 22 as the bucket cylinder 33 expands and contracts. The bucket cylinder 33 has a proximal end connected to the arm 22 and a distal end connected to the bucket via a link. A boom cylinder 31 , an arm cylinder 32 and a bucket cylinder 33 are a plurality of hydraulic actuators that drive the working device 20 .

In addition, construction machines are provided with sensors for detecting information about their positions and attitudes. For example, angle sensors A1 (FIG. 2), A2, and A3 are provided at pivot points of the boom 21, arm 22, and bucket 23, respectively. The angle sensors A1 to A3 are used as attitude sensors for detecting information about the attitude of the work device 20, and detect the angle of the boom 21 with respect to the revolving structure 12, the angle of the arm 22 with respect to the boom 21, and the rotation angle of the bucket 23 with respect to the arm 22, respectively. To detect. In addition, the revolving body 12 is equipped with an inclination sensor (not shown) and a positioning device (not shown). The tilt sensor is used as a posture sensor for the revolving body 12 that detects the tilt of the revolving body 12 in at least one of the longitudinal direction and the lateral direction. For example, an RTK-GNSS (Real Time Kinematic-Global Navigation Satellite System) is used as the positioning device. Information about the position and orientation of the vehicle body 10 is acquired by this positioning device.

－Hydraulic system－
FIG. 2 is a diagram showing a hydraulic system provided in the construction machine shown in FIG. 1 together with a controller and the like. Elements that have already been explained are denoted by the same reference numerals as in the previous drawings, and the explanation thereof is omitted.

The hydraulic system 30 is a device that drives a driven member of the construction machine and is housed mainly in the power chamber 15 . The driven members include the working device 20 (the boom 21, the arm 22 and the bucket 23) and the vehicle body 10 (the crawler 13 and the revolving body 12). The hydraulic system 30 includes hydraulic actuators 31 to 34, an engine 35, a hydraulic pump 36, a control valve unit 38, a pilot pump 37, operating lever devices 51 and 52, a machine control solenoid valve unit 60, and the like. Hereinafter, the machine control solenoid valve unit 60 will be abbreviated as "solenoid valve unit 60".

－Hydraulic Actuator－
The hydraulic actuators 31 to 34 are the boom cylinder 31, the arm cylinder 32, the bucket cylinder 33 and the swing motor . When more than one of the boom cylinder 31, the arm cylinder 32, the bucket cylinder 33, and the swing motor 34 are mentioned, they are called "hydraulic actuators 31 to 34", "hydraulic actuators 31, 32", etc. for convenience. A traveling motor (not shown) is also a hydraulic actuator, but is omitted from FIG. Hydraulic actuators 31 to 34 are driven by hydraulic fluid discharged from hydraulic pump 36 .

-Hydraulic pump-
The hydraulic pump 36 is a variable displacement hydraulic pump that pressurizes hydraulic oil sucked from a tank 39 and discharges it as pressure oil for driving the hydraulic actuators 31 to 34 and the like. This hydraulic pump 36 is driven by the engine 35 . The engine 35 in this embodiment is an internal combustion engine, and is a prime mover that converts combustion energy into power. Although only one hydraulic pump 36 is illustrated in FIG. 2, a plurality of hydraulic pumps may be provided. Hydraulic oil discharged from the hydraulic pump 36 is supplied to the hydraulic actuators 31 to 34 via the control valve unit 38, respectively. Return oil from hydraulic actuators 31 to 34 is returned to tank 39 via control valve unit 38 . A discharge pipe 36a of the hydraulic pump 36 is provided with a relief valve RV that regulates the maximum pressure of the discharge pipe 36a.

－Control valve unit－
The control valve unit 38 is a device for controlling the flow of pressure oil supplied from the hydraulic pump 36 to the plurality of hydraulic actuators 31 to 33, and includes a plurality of control valves. Control valves constituting the control valve unit 38 include at least the boom cylinder 31, the arm cylinder 32, the bucket cylinder 33, the swing motor 34, and the travel motor. Each control valve is a hydraulically driven directional switching valve that controls the flow (direction and flow rate) of hydraulic fluid supplied from the hydraulic pump 36 to the corresponding hydraulic actuator. Pressure drives the spool. When the control valve operates, pressure oil is supplied to the corresponding hydraulic actuator from the direction corresponding to the operation and at a flow rate corresponding to the amount of operation. As a result, for example, the boom 21 rises at a speed corresponding to the operation.

－Pilot pump－
The pilot pump 37 is a fixed displacement hydraulic pump that provides pilot pressure for driving the control valves that constitute the control valve unit 38 , and is driven by the engine 35 like the hydraulic pump 36 . A discharge pipe 37 a of the pilot pump 37 is connected to each valve of the operation lever devices 51 and 52 and the electromagnetic valve unit 60 . The discharge pipe 37a is provided with a pilot relief valve PR that regulates the maximum pressure of the discharge pipe 37a.

－Operation lever device－
The operation lever devices 51 and 52 are lever-operated pressure reducing valve devices that generate and output pilot pressure for driving the control valve unit 38 using the discharge pressure of the pilot pump 37 as the source pressure. The operation lever device 51 is arranged on the left side of the driver's seat, and includes, for example, two pressure reducing valves that generate pilot pressure for driving the control valve for the arm cylinder 32, and a pilot pressure for driving the control valve for the swing motor 34. A total of four pressure reducing valves, two pressure reducing valves for For example, when the operation lever device 51 is tilted to the left, an arm dump operation is commanded, when it is tilted to the right, an arm crowd is commanded, when it is tilted forward, it is turned to the right, and when it is tilted backward, it is commanded to turn to the left. The operating lever device 52 is arranged on the right side of the driver's seat, and includes, for example, two pressure reducing valves that generate pilot pressure for driving the control valves for the bucket cylinder 33, and a pilot pressure that generates pilot pressure for driving the control valves for the boom cylinder 31. A total of four pressure reducing valves, two pressure reducing valves for For example, when the operation lever device 52 is tilted to the left, a bucket cloud is commanded, when it is tilted to the right, a bucket dump is commanded, when it is tilted forward, the boom is lowered, and when it is tilted backward, a boom is raised.

－Machine control solenoid valve unit－
The solenoid valve unit 60 is a device for increasing or decreasing the pilot pressure input from the operating lever devices 51 and 52 to the control valve unit 38 and is interposed between the operating lever devices 51 and 52 and the control valve unit 38 . The electromagnetic valve unit 60 includes an electromagnetically driven pressure reducing valve for reducing the pilot pressure output by the operating lever devices 51 and 52 and an electromagnetically driven pressure increasing valve. The pressure increasing valve is also an electromagnetically driven pressure reducing valve, bypassing the operating lever devices 51 and 52 to directly reduce the discharge pressure of the pilot pump 37, and the pressure generated by the operating lever devices 51 and 52 according to the operation. to generate a pilot pressure greater than the pilot pressure Electromagnetic valves constituting the electromagnetic valve unit 60 are driven by electrical signals output from the controller 100 based on signals from the angle sensors A1 to A3, etc., and the working device 20 operates so that the ground is not excavated beyond the target plane. is restricted.

-controller-
The controller 100 is an in-vehicle computer that controls the electromagnetic valve unit 60 based on the signals from the angle sensors A1 to A3 and restricts the operation of the work device 20 so as not to excavate beyond the target surface. there is The controller 100 is electrically connected to the solenoid valve unit 60, angle sensors A1 to A3, pressure sensors P1 to P8, control dial ED, engine 35, monitor MN, auto idle switch SW1, and machine control switch SW2. there is Regarding the engine 35 , strictly speaking, a so-called engine control unit provided in the engine 35 is connected to the controller 100 .

The pressure sensors P1 to P8 are sensors for detecting the operation of the operating lever devices 51 and 52. The pressure sensors P1 to P8 detect the pilot pressures output from the pressure reducing valves of the operating lever devices 51 and 52, thereby detecting the operating levers. Operation of the devices 51, 52 is detected. For example, the pressure sensor P1 detects a boom raising operation, the pressure sensor P2 detects a boom lowering operation, the pressure sensor P3 detects an arm dump operation, and the pressure sensor P4 detects an arm cloud operation. Further, for example, the pressure sensor P5 detects a bucket dump operation, the pressure sensor P6 detects a bucket cloud operation, the pressure sensor P7 detects a right turn operation, and the pressure sensor P8 detects a left turn operation.

The control dial ED, monitor MN, auto idle switch SW1, and machine control switch SW2 are arranged inside the operator's cab 14 so that the operator can operate them during driving. An engine control dial (engine control dial) ED is a dial for designating a target engine speed. The monitor MN is a display device that displays information of the vehicle body 10 (for example, vehicle body position information, azimuth information, attitude information of the working device 20, distance between the bucket and the target surface, etc.). The auto-idle switch SW1 is a switch for switching between valid and invalid settings of the auto-idle function. The machine control switch SW2 is a switch for switching between enabling and disabling the machine control function.

The construction machine is provided with a temperature sensor T1 for measuring the temperature of the hydraulic oil that drives the hydraulic actuators 31 to 34 and a temperature sensor T2 for measuring the temperature of the engine cooling water, although they can be omitted in this embodiment. there is Signals from these temperature sensors T1 and T2 are also input to the controller 100 .

FIG. 3 is a block diagram of the controller 100. As shown in FIG. The controller 100 is an in-vehicle computer and includes an input interface 101 , a ROM (eg EPROM) 102 , a RAM 103 , a CPU 104 , a timer 105 and an output interface 106 .

Input interface 101 receives signals from angle sensors A1 to A3, pressure sensors P1 to P8, temperature sensors T1 and T2, auto idle switch SW1, machine control switch SW2, control dial ED, and the like.

The ROM 102 stores arithmetic expressions, programs, and data necessary for controlling the engine 35 and the solenoid valve unit 60 . For example, the ROM 102 stores an operation restriction area (set distance L0 [mm] from the target surface to the tip of the bucket) of the working device 20 when the machine control function is enabled. The ROM 102 also stores an invalid region of the auto-idle function (set distance L1 [mm] from the target surface to the tip of the bucket) in the auto-idle automatic on/off function (described later). In addition, the idling speed N0 (for example, 1400 rpm), which is the preset speed for auto idling of the engine 35, and the prescribed speed Ns (for example, 1800 rpm) for the engine 35 during machine control metering learning are also stored in the ROM 102. It is The set distance L1 is preferably larger than the set distance L0 (L1>L0) from the viewpoint of returning the engine speed to the specified engine speed Ns before the machine control starts functioning, and is set to at least the set distance L0 or more. (L1≧L0).

The CPU 104 executes predetermined processing based on each signal input via the input interface 101 according to a program loaded from the ROM 102 .

The RAM 103 temporarily stores numerical values during calculation. The RAM 103 stores, for example, the current setting information of enable/disable of the auto idle function designated by the auto idle switch SW1 and the current setting information of enable/disable of the machine control function designated by the machine control switch SW2. It is The current designated rotation speed [rpm] of the engine 35 designated by the control dial ED is also stored in the RAM 103 .

The output interface 106 outputs command signals to the engine 35 (engine control unit) and the solenoid valve unit 60 according to commands from the CPU 104 .

Next, the functions executed by the CPU 104 according to the programs stored in the ROM 102 will be exemplified in order.

-Machine control function-
4 and 5 are schematic diagrams used to describe the functions of the controller 100. FIG. An overview of the functions of the controller 100 will be described with reference to these figures.

First, the controller 100 controls the electromagnetic valve unit 60 based on the signals of the plurality of angle sensors A1 to A3, and restricts the operation of the working device 20 so that the ground is not excavated beyond the target plane (broken line). It has a machine control function. When this function is enabled, the controller 100 calculates the distance L [mm] between the target surface and the tip of the bucket 23 based on the signals from the angle sensors A1 to A3, and operates the solenoid valve unit 60 according to the calculated distance L. It controls and intervenes in the operation of the operator to limit the operating area of the work implement 20 . Details of the machine control function are omitted, but are described in detail in, for example, Japanese Patent Application Laid-Open Nos. 8-333768, 2016-003442, and 2019-052515.

-Auto idle function-
The controller 100 also has an auto-idle function that automatically lowers the engine speed to a preset idle speed N0, for example, when no operation continues for a certain period of time. A detailed description of the auto idle function is omitted, but is described in detail in, for example, JP-A-09-068169 and JP-A-2018-048571.

- Auto idle automatic on/off function -
A characteristic function of the controller 100 is an automatic on/off function of auto idle in conjunction with the machine control function. Even if the auto-idle function is enabled by the auto-idle switch SW1, when the machine control function is enabled, the auto-idle function is automatically switched between enabled and disabled according to the distance L between the tip of the bucket 23 and the target surface. . Specifically, the controller 100 first determines whether the machine control function and the auto idle function are enabled or disabled based on signals from the auto idle switch SW1 and the machine control switch SW2. When it is determined that both the machine control function and the auto idle function are valid, the controller 100 performs auto idle if the distance L between the tip of the bucket 23 and the target surface is equal to or less than the set distance L1 as shown in FIG. Automatically disable features. Even if the auto-idle function is temporarily disabled in this manner, the controller 100 cancels the temporary disabling of the auto-idle function and enables the auto-idle function when the distance L exceeds the set distance L1 as shown in FIG. Return to valid state. In other words, when both the machine control function and the auto idle function are enabled, the automatic idle control is performed only when the distance L between the toe of the bucket 23 and the target surface is greater than the set distance L1 as shown in FIG. Idle function is activated. Information indicating whether the auto idle function is valid or invalid is displayed on the monitor MN by a command signal from the controller 100 .

The distance L has a positive value when the toe of the bucket 23 is higher than the target surface, and a negative value when the toe of the bucket 23 is lower than the target surface. It is set in the range of positive values. The set distance L1 is set in advance and stored in the ROM 102 (FIG. 3), for example, as described above.

-motion-
FIG. 6 is a flow chart showing the procedure of automatic ON/OFF control of the auto-idle function by the controller. The controller 100 repeatedly executes the procedure of FIG. 6 in a predetermined processing cycle (for example, 0.1 s) during operation (while power is being supplied).

<Step S11>
For example, when the engine 35 is started by a key switch and power is supplied, the controller 100 starts the procedure shown in FIG. . Specifically, signals from the angle sensors A1 to A3, the pressure sensors P1 to P8, the auto idle switch SW1, the machine control switch SW2, and the control dial ED are input through the input interface 101. FIG. Also, the set distance L1, the idle speed N0 [rpm], and the specified speed Ns [rpm] are read from the ROM 102 .

<Step S12>
Next, the controller 100 determines whether the auto idle function is enabled (manually set) based on the signal of the auto idle switch SW1 (step S12). If the controller 100 determines that the auto-idle function is disabled (manually set), it proceeds to step S18 (described later), and if it determines that the auto-idle function is enabled (manually set), it proceeds to step S18. Move the procedure to S13.

<Step S13>
When the auto idle function is enabled, the controller 100 determines whether or not the hydraulic actuators such as the boom cylinder 31, the arm cylinder 32, the bucket cylinder 33, the swing motor 34, and the travel motor have been operated for a set time or longer (step S13). This determination is made based on, for example, the history of the operation signals including the pressure sensors P1 to P8 recorded in the RAM 103, and the state in which all the operation signals are off (a value below a predetermined value and does not exceed the dead zone) is the set time. Satisfied if it continues for more than This is the determination result that the non-operation state continues for the set time or more. Conversely, if any of the operation signals is ON (a value greater than the predetermined value and exceeding the dead band) within the set time before the current time, the determination in step S13 is not satisfied. This is the determination result that the duration of the non-operation state is less than the set time. If the controller 100 determines that the duration of the non-operating state is less than the set time, it proceeds to step S18 (described later). to move.

<Step S14>
If the non-operating state continues for the set time or longer, the controller 100 determines whether the machine control function is enabled (manually set) based on the signal from the machine control switch SW2 (step S14). When determining that the machine control function is disabled (manually set), the controller 100 proceeds to step S17 (described later). If it is determined that the machine control function is enabled (manually set), that is, if both the auto idle function and the machine control function are enabled, the controller 100 proceeds to step S15.

<Steps S15, S16>
When both the auto idle function and the machine control function are valid, the controller 100 calculates the distance L between the bucket toe and the target surface based on the signals from the angle sensors A1 to A3 (step S15), and the distance L is set. It is determined whether the distance is greater than the distance L1 (step S16). If the distance L is equal to or less than the set distance L1 (L≦L1), the controller 100 proceeds to step S18 (described later), and if the distance L is greater than the set distance L1 (L>L1), the controller 100 proceeds to step S17.

<Step S17>
After moving the procedure to step S17, the controller 100 sets the target rotation speed Nt to the idle rotation speed N0 and outputs a command signal to the engine controller to drive the engine 35 at the idle rotation speed N0. If the auto idle function is valid and the machine control function is invalid, the target rotation speed Nt is automatically set to the idle rotation speed N0 if the non-operating state continues for the set time or longer (step S14→ S17). Even if the machine control function is effective, if the toe of the bucket is away from the target surface (L>L1), the auto idle function is effective and if the non-operating state continues for the set time or longer, the target rotation speed Nt will be idle. The rotational speed is set to N0 (step S16→S17).

<Step S18>
On the other hand, after moving the procedure to step S18, the controller 100 sets the target rotation speed Nt to the specified rotation speed Ns and outputs a command signal to the engine controller to drive the engine 35 at the specified rotation speed Ns. The prescribed rotation speed Ns is the set rotation speed (for example, 1800 rpm) at the time of machine control metering learning. If the auto-idle function is disabled, or if the no-operation state is less than the set time even if the auto-idle function is enabled, the target rotation speed Nt is set to the specified rotation speed Ns (steps S12→S18, step S13→S18). Even if the auto-idle function is valid and no operation continues, if the machine control function is valid and the toe of the bucket is approaching the target surface (L≤L1), the target rotation speed Nt is the specified rotation speed. Ns is set (step S16→S18). In other words, even if the auto-idle function is manually activated by the auto-idle switch SW1, when the machine control function is activated, the auto-idle function is automatically temporarily activated when the bucket toe approaches the target surface (when L≤L1). Disabled.

When the procedure moves to step S18 via step S12 or S13, and although not shown, if the machine control function is disabled, the specified rotation speed specified by the control dial ED is set as the target rotation speed Nt. It can be configured to

<Steps S19, S20>
After setting the target rotation speed Nt in step S17 or S18, the controller 100 instructs the monitor MN to display information indicating whether the auto idle function is valid or invalid (step S19). As a result, the on/off state of the auto-idle function is displayed on the monitor MN, and the operator is also notified that the auto-idle function enabled by the auto-idle switch SW1 is automatically and temporarily disabled in relation to the machine control function. be. Then, the controller 100 determines whether the power is turned off by, for example, a key switch (step S20). The process of FIG. 6 ends.

-effect-
(1) In this embodiment, when both the machine control function and the auto idle function are enabled, the auto idle function is forcibly activated if the distance L between the bucket tip and the target surface is equal to or less than the set distance L1. Temporarily disabled. Even if the machine control function is valid, when the auto idle function is manually set to be valid, the auto idle function works when no operation is performed if the distance L between the toe of the bucket and the target surface is larger than the set distance L1. As described above, according to the present embodiment, both the machine control function and the auto idle function can be made compatible, and even when the machine control function is in use, the engine speed drops to the idle speed N0 under certain conditions when there is no operation. Energy saving effect is improved.

(2) Even if the auto-idle function is manually enabled by the auto-idle switch SW1, if the machine control function is enabled as described above, the auto-idle function is forcibly disabled under predetermined conditions. . In this embodiment, by displaying information on whether the auto idle function is valid or invalid on the monitor MN, the operator can confirm the situation at any time, such as whether the auto idle function has been forcibly invalidated. can do.

(Second embodiment)
FIG. 7 is a flow chart showing the procedure of automatic ON/OFF control of the auto idle function by the controller provided in the construction machine according to the second embodiment of the present invention. This embodiment differs from the first embodiment in that the idling speed N0, which is the set speed during auto idling, changes according to the distance L between the bucket toe and the target surface under predetermined conditions. Specifically, when it is determined that the settings of both the machine control function and the auto idle function are valid, the controller 100 increases the idle rotation speed N0 as the distance L decreases in a region where the distance L is greater than the set distance L1. set. The procedures of steps S22, S23, S27 to S30 in FIG. 7 are the same as the procedures of steps S12, S13, S17 to S20 in the first embodiment described in FIG.

<Step S21>
For example, when the engine 35 is started by a key switch and power is supplied, the controller 100 starts the procedure shown in FIG. . Specifically, signals from the angle sensors A1 to A3, the pressure sensors P1 to P8, the auto idle switch SW1, the machine control switch SW2, and the control dial ED are input through the input interface 101. FIG. Also, the set distance L1, the idle speed N0, the specified speed Ns, and reference data (described later) are read from the ROM 102. FIG.

The reference data is a graph or data table that defines the relationship between the distance L from the target surface to the tip of the bucket and the target rotation speed Nt, and defines characteristics such as those shown in FIGS. 8 and 9, for example. This reference data is created in advance based on the specified rotational speed Ns and the set distances L1 and L2 and stored in the ROM 102 . The set distance L2 is a value set larger than the set distance L1.

In the reference data, the target rotation speed Nt of the engine 35 is defined as the specified rotation speed Ns (constant value) in the region where the distance L is less than the set distance L1 (L<L1), and in the region where the set distance L1 or more (L≧L1 ), the idle speed is defined as N0 [rpm]. The idling speed N0 in the present embodiment changes according to the distance L, and in the range of the set distance L1 or more and less than the set distance L2 (L1≦L<L2), the preset minimum idling speed Nm It monotonically decreases as the distance L increases up to [rpm]. In the range of the set distance L2 or more (L≧L2), the idling speed N0 is defined as the minimum idling speed Nm (constant value). For the minimum idle rotation speed Nm, for example, the same value as the constant idle rotation speed N0 in the first embodiment can be adopted. As a change form of the variable idling speed N0 in this embodiment, as shown in FIG. be able to. As shown in FIG. 9, the idling speed N0 may decrease stepwise as the distance L increases in the region between the set distances L1 and L2. According to this reference data, the target rotation speed Nt is uniquely determined based on the distance L.

In the region of L1≦L<L2, it is possible to consider a form in which the target rotation speed Nt is constant at an intermediate value between the specified rotation speed Ns and the minimum idle rotation speed Nm (for example, if Ns=1800rpm, Nm=1400rpm, then 1700rpm, etc.). be done.

<Steps S22 to S24>
Next, the controller 100 determines whether or not the auto idle function is manually enabled (step S22) in the same manner as in step S12 of FIG. If valid, the procedure moves to step S23. If the auto-idle function is manually enabled, the controller 100 determines whether the non-operating state has continued for the set time or more in the same manner as in step S13 of FIG. 6 (step S23). If the duration of the non-operating state is less than the set time, the procedure goes to step S28 (described later), and if it is longer than the set time, the procedure goes to step S24.

If the non-operating state has continued for the set time or more, the controller 100 determines whether the machine control function is manually enabled (step S24), similarly to step S14 in FIG. If the machine control function is disabled, the controller 100 proceeds to step S27 (to be described later). If the machine control function is enabled, that is, if both the auto idle function and the machine control function are enabled, the controller 100 proceeds to step S25.

<Steps S25, S25a>
When both the auto-idle function and the machine control function are valid, the controller 100 calculates the distance L between the bucket toe and the target plane (step S25), as in step S25 of FIG. Then, the target rotation speed Nt (=Ns or N0) corresponding to the distance L is calculated according to the reference data (step S25a).

<Steps S26 to S30>
When both the auto idle function and the machine control function are valid, the controller 100 outputs a command signal to the engine controller to drive the engine 35 at the target rotation speed Nt calculated in step S25a (step S16). In step S25a, the target rotation speed Nt corresponding to the distance L is calculated according to the reference data. Nt is set to the prescribed rotation speed Ns. This is synonymous with automatically temporarily disabling the auto-idle function in the area less than the set distance L1 in the first embodiment. On the other hand, in the range of the set distance L1 or more, the auto idle function works effectively, and the target rotation speed Nt is set to the idle rotation speed N0 lower than the specified rotation speed Ns.

<Step S27>
If the auto idle function is valid and there is no operation for a set time or more, and if the machine control function is invalid, the controller 100 sets the target rotation speed Nt to the idle rotation speed N0 regardless of the distance L and sends a command signal to the engine controller. Output (step S27). As a result, the rotation speed of the engine 35 drops to the idle rotation speed N0 (minimum idle rotation speed N0).

<Step S28>
If the auto idle function is disabled or if the no-operation state is less than the set time even if the auto idle function is enabled, the controller 100 unconditionally sets the target rotation speed Nt to the prescribed rotation speed Ns and outputs a command signal to the engine controller. (step S28). As a result, the engine 35 is driven at the prescribed rotation speed Ns. As described in the first embodiment, if the machine control is disabled, the specified rotation speed specified by the control dial ED may be set as the target rotation speed Nt.

<Steps S29, S30>
After setting the target engine speed Nt in steps S26, S27 or S28, the controller 100 displays information indicating whether the auto idle function is valid or invalid on the monitor MN (step S29), as in step S19 of FIG. Further, the controller 100 determines whether the power is turned off by, for example, a key switch (step S30). The process of FIG. 6 ends.

In other respects, this embodiment is the same as the first embodiment.

In this embodiment as well, both the machine control function and the auto idle function can be made compatible, and even when the machine control function is in use, the engine speed drops under certain conditions when there is no operation, improving the energy saving effect. In addition, with the preset idle rotation speed N0 as the minimum value, the idle rotation speed increases as the bucket 23 approaches the auto-idle automatic invalidation region. As a result, the engine speed can be reliably increased to the prescribed speed Ns for machine control before the machine control function works.

(Third embodiment)
FIG. 10 is a flow chart showing the procedure of automatic ON/OFF control of the auto idle function by the controller provided in the construction machine according to the third embodiment of the present invention. This embodiment differs from the first embodiment in that the set distance L1 (the threshold value used in the determination in step S16) for the distance L between the bucket toe and the target surface depends on at least one of the hydraulic oil temperature and the engine cooling water temperature. It is a point that changes with time. Specifically, when the controller 100 determines that the settings of both the machine control function and the auto idle function are valid, the lower the temperature measured by the temperature sensors T1 and T2, the larger the set distance L1 is set. (step S14a). In this embodiment, the procedure of step S14a is added between steps S14 and S15 to the procedure of the first embodiment (FIG. 6). Further, in this embodiment, reference data (FIGS. 11 and 12) about the set distance L1 are added to the basic information input to the controller 100 in step S11 in addition to the signals from the temperature sensors T1 and T2. In other respects, the procedure of the present embodiment shown in FIG. 10 is the same as the procedure of the first embodiment described with reference to FIG. Differences from the first embodiment will be described below.

－Reference data－
FIG. 11 is a diagram schematically showing reference data defining the relationship between the hydraulic oil temperature [° C.] and the set distance L1. The reference data shown in the figure is a graph or data table defining the relationship between the hydraulic oil temperature To [° C.] and the set distance L1, and is created and stored in the ROM 102 in advance. In the figure, set temperatures To1 [° C.] and To2 [° C.] (To1<To2) are set for the hydraulic oil temperature To. is monotonically shortened from the maximum value Lmax to Lmin. In the range of To<To1, the set distance L1 is constant at the maximum value Lmax, and in the range of To≧To2, the set distance L1 is constant at the minimum value Lmin. The variation of the set distance L1 is not limited to the mode of (continuously) decreasing in proportion to the hydraulic oil temperature To within the range of To1≦To<To2 as shown in FIG. A stepped form as shown in 9 may also be used. According to this reference data, the set distance L1 corresponding to the hydraulic oil temperature To is uniquely determined.

FIG. 12 is a diagram schematically showing reference data defining the relationship between the engine cooling water temperature [° C.] and the set distance L1. The reference data shown in the figure is a graph or data table defining the relationship between the engine coolant temperature Tw [° C.] and the set distance L1, and is created and stored in the ROM 102 in advance. In the figure, set temperatures Tw1 [° C.] and Tw2 [° C.] (Tw1<Tw2) are set for the engine cooling water temperature Tw. As the engine coolant temperature Tw increases within the range of Tw1≦Tw<Tw2, the set distance L1 monotonically decreases from the maximum value Lmax to Lmin. In the range of Tw<Tw1, the set distance L1 is constant at the maximum value Lmax, and in the range of Tw≧Tw2, the set distance L1 is constant at the minimum value Lmin. The setting distance L1 is not limited to (continuously) decreasing in proportion to the engine coolant temperature Tw within the range of Tw1≦Tw<Tw2 as shown in FIG. A stepped form as shown in FIG. 9 may be employed. According to this reference data, the set distance L1 corresponding to the engine cooling water temperature Tw is uniquely determined.

-Automatic on/off control-
As shown in FIG. 11, in this embodiment, when both the auto idle function and the machine control function are enabled, the controller 100 moves the procedure from step S14 to step S14a. After moving the procedure to step S14a, the controller 100 calculates the set distance L1 according to the temperature according to the reference data. The set distance L1 may be determined based only on the hydraulic oil temperature measured by the temperature sensor T1, or may be determined based only on the engine coolant temperature measured by the temperature sensor T2. The temperatures measured by the temperature sensors T1 and T2 are used as the basis for calculating the set distance L1, and the maximum value of the set distance L1 corresponding to the operating oil temperature To and the set distance L1 corresponding to the engine cooling water temperature Tw is used in step S16. It is also possible to employ a configuration in which the set distance L1 is selected. An example of setting the average value or the minimum value of the set distance L1 corresponding to the operating oil temperature To and the set distance L1 corresponding to the engine cooling water temperature Tw as the set distance L1 used in step S16 is also conceivable. Then, after executing the process of step S14a, the controller 100 shifts the procedure to step S15, and calculates the distance L between the bucket tip and the target surface. The execution order of steps S14a and S15 may be reversed, or parallel operations may be performed.

In other respects, this embodiment is the same as the first embodiment.

Also in this embodiment, when both the machine control function and the auto-idle function are enabled, the auto-idle function is automatically disabled temporarily when the bucket approaches the target plane. can be compatible.

In addition, in this embodiment, the set distance L1 changes according to the operating oil temperature To and the engine cooling water temperature Tw. For example, the hydraulic oil temperature To affects the rise of the pump torque, and when the hydraulic oil temperature To is low, the pump torque rises slowly. Therefore, by setting the set distance L1 long when the hydraulic oil temperature To is low as in this embodiment, the machine control function operates before the engine speed reaches the specified speed Ns from the idle speed N0. can be suppressed. Work accuracy can be ensured by operating the machine control function under the same conditions (specified rotation speed Ns) as during metering learning. Conversely, when the hydraulic oil temperature To is high, even if the set distance L1 is shortened, the engine speed rises up to the specified speed Ns with good response, so the effective range of the auto idle function expands and an improvement in the energy saving effect can be expected. .

On the other hand, the engine cooling water temperature Tw affects the startup of the engine speed. When the engine cooling water temperature Tw is low, the engine rotation speed rises slowly. You can prevent machine control functions from working. Conversely, when the engine coolant temperature Tw is high, the engine speed rises to the specified speed Ns with good response even if the set distance L1 is shortened. can be expected to improve.

DESCRIPTION OF SYMBOLS 10... Vehicle body, 20... Working apparatus, 31... Boom cylinder (hydraulic actuator), 32... Arm cylinder (hydraulic actuator), 33... Bucket cylinder (hydraulic actuator), 34... Swing motor (hydraulic actuator), 36... Hydraulic pump, 37... Pilot pump, 38... Control valve unit, 51, 52... Operation lever device, 60... Machine control electromagnetic valve unit, 100... Controller, A1 to A3... Angle sensor (orientation sensor), L... Tip of bucket and target surface L1: set distance, MN: monitor, N0: idling speed, SW1: auto idle switch, SW2: machine control switch, T1, T2: temperature sensor

Claims (3)

A vehicle body, a work device attached to the vehicle body, a plurality of hydraulic actuators for driving the work device, a plurality of attitude sensors for detecting the posture of the work device, and a discharge of pressurized oil for driving the plurality of hydraulic actuators. a hydraulic pump, a pilot pump, a control valve unit for controlling the flow of pressure oil supplied from the hydraulic pump to the plurality of hydraulic actuators, and a discharge pressure of the pilot pump as a source pressure to drive the control valve unit. a machine control solenoid valve unit provided between the plurality of operation lever devices and the control valve unit; and an auto idle switch for switching between enabling and disabling the auto idle function. a machine control switch for switching between enabling and disabling the machine control function; a monitor for displaying information about the vehicle body; and a controller that restricts the operation of the work device so that the ground is not excavated beyond
When the controller determines that the setting of both the machine control function and the auto-idle function is effective based on the signals from the machine control switch and the auto-idle switch, the distance L between the toe of the bucket and the target surface is is equal to or less than the set distance L1, the auto idle function is automatically disabled when the distance L between the toe of the bucket and the target surface is greater than the set distance L1, and the auto idle function is enabled;
When the controller determines that the settings of both the machine control function and the auto-idle function are valid, the setting rotation during auto-idling increases as the distance L decreases in a region where the distance L is greater than the set distance L1. A construction machine characterized by setting a large number of idling revolutions. A vehicle body, a work device attached to the vehicle body, a plurality of hydraulic actuators for driving the work device, a plurality of attitude sensors for detecting the posture of the work device, and a discharge of pressurized oil for driving the plurality of hydraulic actuators. a hydraulic pump, a pilot pump, a control valve unit for controlling the flow of pressure oil supplied from the hydraulic pump to the plurality of hydraulic actuators, and a discharge pressure of the pilot pump as a source pressure to drive the control valve unit. a machine control solenoid valve unit provided between the plurality of operation lever devices and the control valve unit; and an auto idle switch for switching between enabling and disabling the auto idle function. a machine control switch for switching between enabling and disabling the machine control function; a monitor for displaying information about the vehicle body; and a temperature sensor for at least one of a sensor for measuring hydraulic oil temperature and a sensor for measuring engine cooling water temperature . in the machine
When the controller determines that the setting of both the machine control function and the auto-idle function is effective based on the signals from the machine control switch and the auto-idle switch, the distance L between the toe of the bucket and the target surface is is equal to or less than the set distance L1, the auto idle function is automatically disabled when the distance L between the toe of the bucket and the target surface is greater than the set distance L1, and the auto idle function is enabled;
When the controller determines that the settings of both the machine control function and the auto idle function are valid, the controller sets the set distance L1 larger as the temperature measured by the temperature sensor decreases. construction machinery. 3. The construction machine according to claim 1, wherein said controller instructs said monitor to display information indicating whether said auto idle function is valid or invalid.

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