JP4282871B2 - Hydraulic traveling vehicle - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a hydraulic traveling vehicle such as a wheeled hydraulic excavator having an auto idle function.
[0002]
[Prior art]
A wheeled hydraulic excavator adjusts the engine speed with an accelerator pedal, adjusts the direction and flow rate of pressure oil from the variable displacement hydraulic pump with a travel control valve, and rotates the travel hydraulic motor, thereby moving forward and backward. And controlling the vehicle speed. Such a wheel-type hydraulic excavator is equipped with a work accelerator function that adjusts the engine speed by an accelerator pedal during work, and when the work actuator and the travel actuator have not been operated for a predetermined time or more, An auto idle function is mounted to reduce the number to a predetermined idle speed.
[0003]
The operation / non-operation of the work actuator and the travel actuator is detected by operating / non-operating the control valve of each actuator. In other words, a route is provided to guide the pressure oil from the pilot pump to the tank via each control valve. If the pressure on the most upstream side of this route is the tank pressure, all the control valves are not operated, and the pressure is not less than a predetermined value. If so, it can be determined that one of the control valves is operated.
[0004]
[Problems to be solved by the invention]
In such a conventional wheel-type hydraulic excavator, since the travel control valve is detected as non-operating during the work accelerator, the engine speed is set at a predetermined speed greater than or equal to the idle speed by depressing the accelerator pedal. Even when the engine is rotating, if all the operating levers are not operated for a predetermined time or more, the engine speed is automatically reduced to the idle speed, which may give the driver a sense of incongruity. This is because the auto-idle condition is not finely set according to the application.
[0005]
An object of the present invention is to provide a hydraulic traveling vehicle in which the auto-idle function is prohibited and the operability is improved when the number of revolutions is adjusted with an accelerator pedal during work.
Another object of the present invention is to provide a hydraulic traveling vehicle capable of setting a highly versatile auto idle function by switching auto idle conditions according to the purpose of use of the hydraulic traveling vehicle.
[0006]
[Means for Solving the Problems]
  The present invention will be described with reference to the drawings of the embodiments.
  The hydraulic traveling vehicle according to claim 1 includes a variable displacement hydraulic pump 10, 20 driven by a prime mover 41, a traveling hydraulic motor 31 driven by pressure oil discharged from the variable displacement hydraulic pump 10, 20, A plurality of working hydraulic actuators 32 to 35 driven by pressure oil discharged from the variable displacement hydraulic pumps 10, 20, an accelerator pedal 51 for adjusting the rotational speed of the traveling hydraulic motor 31, a fuel lever 65 a and an accelerator pedal 51, a rotation speed adjusting means 63 for adjusting the rotation speed of the prime mover 41 in accordance with the operation amount of any one of the motors 51, an operation lever means BL for operating each of the plurality of working hydraulic actuators 32-35, and a predetermined auto idle condition Is established, prime mover rotational speed reduction means 607, 610, 611 for reducing the rotational speed of the prime mover 41 to a predetermined low rotational speed, and a fuel lever Comprising first and work performed by adjusting the rotational speed by 5a, and a switching means 607 and 610 for switching the auto idle condition in response to the second work and the traveling and performed by adjusting the rotational speed with the accelerator pedal 51. Furthermore, the auto-idle condition of the first work isEven if the fuel lever is operatedAll of the operating lever means BL is longer than the predetermined timeNeutralIn addition, the second work and traveling auto-idle condition includes that all of the operation lever means BL are not operated and the accelerator pedal 51 is not operated.
[0007]
  Claim1'sHydraulic traveling vehicle according to the inventionThen switchThe means 607, 610 switches the auto-idle condition according to the first work performed by adjusting the rotational speed by the fuel lever 65a, the second work performed by adjusting the rotational speed by the accelerator pedal 51, and traveling. . As a result, it is possible to individually set auto-idle conditions according to the purpose of use of the hydraulic traveling vehicle.
[0008]
In the section of the means for solving the above-described problem to explain the configuration of the present invention, the drawings of the embodiments are used for easy understanding of the present invention, but the present invention is thereby limited to the embodiments. It is not something.
[0009]
[Embodiment]
A case where the present invention is applied to a wheeled hydraulic excavator will be described with reference to FIGS. The wheel-type hydraulic excavator has a swivel mounted on a wheel-type traveling body so as to be able to swivel, and a work attachment is attached to the swivel.
[0010]
FIG. 1 shows a hydraulic circuit of a wheeled hydraulic excavator according to the present invention. The hydraulic circuit includes main pumps 10 and 20 driven by an engine (not shown), four control valves 11 to 14 arranged in series with the main pump 10, and arranged in series with the main pump 20. The five control valves 21 to 25, the traveling motor 31 driven by the pressure oil controlled by the control valves 11 and 25, the bucket cylinder 32 driven by the pressure oil controlled by the control valve 12, and the control Boom cylinder 33 driven by pressure oil controlled by valves 13 and 23, arm cylinder 34 driven by pressure oil controlled by control valves 14 and 22, and driven by pressure oil controlled by control valve 21 The turning motor 35 is provided. The control valve 24 is a spare control valve. The traveling motor 31, the boom cylinder 33, and the arm cylinder 34 are driven by a merging circuit that speeds up the operation speed by the pressure oil from the main pumps 10 and 20 merging. The pilot pump 10A supplies pilot pressure oil to a pilot circuit, which will be described later, and is also supplied to an operation lever operation / non-operation detection circuit based on auto idle control, which will be described later.
[0011]
FIG. 2 is a diagram showing details of the traveling hydraulic circuit shown in FIG. The traveling hydraulic circuit in FIG. 2 is shown for one main pump 10 and one traveling control valve 11 in FIG. As shown in FIG. 2, the direction and flow rate of the discharge oil from the main pump 10 driven by the engine (prime mover) 41 is controlled by the control valve 11, and travels through the brake valve 43 incorporating the counter balance valve 42. It is supplied to the motor 31. A transmission 44 is connected to the output shaft of the travel motor 31. The rotation of the traveling motor 31 drives the tire 47 via the transmission 44, the propeller shaft 45, and the axle 46, and the wheeled hydraulic excavator travels.
[0012]
The displacement volume (tilt amount) of the main pump 10 is adjusted by the regulator 48 in accordance with the pump discharge pressure. The regulator 48 is provided with a torque limiter, and pump discharge pressure is fed back to the torque limiter to perform so-called horsepower control.
[0013]
The switching direction and stroke amount of the control valve 11 are controlled by the pilot pressure from the pilot circuit. The travel speed of the vehicle can be controlled by adjusting the stroke amount. The pilot circuit includes a pilot pump 10A also shown in FIG. 1, a traveling pilot valve 52 that generates a pilot secondary pressure in response to depression of the accelerator pedal 51, and a return oil to the pilot valve 52 that follows the pilot valve 52. And a forward / reverse switching valve 54 for selecting forward, reverse, or neutral of the vehicle following the slow return valve 53. The forward / reverse switching valve 54 is an electromagnetic switching valve that is switched by a forward / reverse switch 66 described later. The traveling pilot pressure is detected by a pressure sensor 69 described later.
[0014]
FIG. 2 shows a state in which the forward / reverse switching valve 54 is neutral (N position) and the traveling pilot valve 52 is not operated. Therefore, the control valve 11 is in the neutral position, and the pressure oil from the main pump 10 is Returning to the tank, the vehicle is stopped. When the forward / reverse switching valve 54 is switched to forward (F position) or reverse (R position) and the accelerator pedal 51 is depressed, a pilot secondary pressure corresponding to the amount of depression is generated. The pilot pressure generated in proportion to the operation of the accelerator pedal 51 is output as forward pilot pressure oil and reverse pilot pressure oil through the forward / reverse switching valve 54 and acts on the pilot port of the control valve 11. The control valve 11 is switched by a stroke amount corresponding to the pilot pressure. By switching the control valve 11, the oil discharged from the main pump 10 is guided to the traveling motor 31 via the control valve 11, the center joint 55, and the brake valve 43, and the traveling motor 31 is driven to run the wheel hydraulic excavator. To do.
[0015]
The traveling motor 31 has a self-pressure tilt control mechanism. When the driving pressure exceeds a predetermined value, the volume is increased as the pressure increases, and the volume is driven at a low speed / high torque, and the volume is increased as the driving pressure decreases. Smaller and driven at high speed and low torque. The driving pressure acts on the control piston 58 and the servo piston 59 of the traveling motor 31 from the shuttle valve 56.
[0016]
When the accelerator pedal 51 is released during traveling, the traveling pilot valve 52 shuts off the pressure oil from the pilot pump 10A, and its outlet port communicates with the tank. As a result, the pressure oil acting on the pilot port of the control valve 11 returns to the tank via the forward / reverse switching valve 54, the slow return valve 53, and the traveling pilot valve 52. At this time, since the return oil is throttled by the throttle of the slow return valve 53, the control valve 11 is gradually switched to the neutral position. When the control valve 11 is switched to the neutral position, the discharge oil from the main pump 10 returns to the tank, the supply of pressure oil (drive pressure) to the traveling motor 31 is shut off, and the counter balance valve 42 is also in the neutral position shown in the figure. Switch.
[0017]
In this case, the vehicle body continues to travel due to the inertial force of the vehicle body, and the traveling motor 31 changes from a motor action to a pump action. In the drawing, the B port side is suctioned and the A port side is discharged. Since the pressure oil from the travel motor 31 is throttled by the throttle (neutral throttle) of the counter balance valve 42, the pressure between the counter balance valve 42 and the travel motor 31 rises and acts on the travel motor 31 as a brake pressure. . As a result, the traveling motor 31 generates brake torque to brake the vehicle body. If the intake oil amount is insufficient during the pump operation, the travel motor 31 is replenished with the oil amount from the makeup port MP. The brake pressure is regulated by relief valves RV1 and RV2.
[0018]
Since the return oil from the relief valves RV1 and RV2 is guided to the suction side of the traveling motor 31, a closed circuit is formed inside the motor during the relief, and the hydraulic oil temperature rises, which may adversely affect the equipment. Therefore, a small amount of pressurized oil is released from the neutral throttle of the counter balance valve 42 and led to the control valve 11, and the A and B ports are communicated within the control valve 11 (A-B communication). A circulation circuit returning to the side is formed to cool the hydraulic oil temperature.
[0019]
When the accelerator pedal 51 is released on a downhill, a hydraulic brake is generated as in the case of deceleration described above, and the hill is lowered by inertia traveling while braking the vehicle. During downhill, even when the accelerator pedal 51 is depressed, the counter balance valve 42 is operated, and the hydraulic brake is applied so that the motor rotation speed (travel speed) according to the inflow rate from the main pump 10 to the travel motor 31 is achieved. Generate pressure.
[0020]
The work attachment of the wheel-type hydraulic excavator includes, for example, a boom, an arm, and a bucket. The operator's cab is provided with pilot operation levers for arms, booms and buckets. FIG. 3 shows a boom pilot circuit as a representative of the work attachment pilot circuit. When the boom operating lever BL is operated, the hydraulic pilot switching boom control valves 13 and 23 (FIG. 1) are switched by the pressure from the pilot pump 10A which is decompressed by the pressure reducing valve (pilot valve) PV according to the operation amount. Instead, the discharged oil from the main pump 10 is guided to the boom cylinder 33 through the control valves 13 and 23, and the boom is raised and lowered by the expansion and contraction of the boom cylinder 33. When the boom operating lever BL is operated to the boom raising side, the boom raising pilot pressure oil is supplied to the bottom side of the boom cylinder 33, and when operated to the boom lowering side, the boom lowering pilot pressure oil is supplied to the rod side of the boom cylinder 33.
[0021]
Although not shown in FIGS. 1 and 4, an arm lever, a bucket lever, and a turning lever are provided in addition to the boom operation lever BL and the accelerator pedal 51, and in accordance with the operation amount of each lever in the same manner as the boom lever BL. A pressure reducing valve (pilot valve) that discharges pilot pressure oil, a control valve that is switched by the discharged pilot pressure oil, and an actuator that is driven by pressure oil from the control valve are provided.
[0022]
FIG. 4 is a diagram for explaining a circuit for detecting an operation / non-operation state of an operation lever used for auto idle control. The main pumps 10, 20 and the pilot pump 10A and the control valves 11-14, 21-25 are shown in FIG. The oil discharged from the pilot pump 10A is supplied to the bucket control valve 12, the boom control valve 13, the arm control valve 14, the turning control valve 21, the arm control valve 22, and the boom control valve 23 through the pipe L1. And through the spare control valve 24 to the tank. A throttle 16 is provided in the pipe L 1, and an auto idle pressure switch 17 is provided on the downstream side of the throttle 16. When any one of the control valves 12 to 14 and 21 to 24 is operated, the pressure in the pipe L1 on the downstream side of the throttle 16 is increased, the pressure switch 17 is turned on, and the control valve, that is, the operation lever is turned on. It is detected that it has been operated.
[0023]
FIG. 5 is a block diagram of a control circuit for controlling the engine speed, and each device is controlled by a controller 60 constituted by a CPU or the like. The governor 61 of the engine 41 is connected to the pulse motor 63 via the link mechanism 62, and the rotation speed of the engine 41 is controlled by the rotation of the pulse motor 63. That is, the rotational speed increases when the pulse motor 63 rotates forward and decreases when the pulse motor 63 rotates backward. The rotation of the pulse motor 63 is controlled by a control signal from the controller 60. A potentiometer 64 is connected to the governor 61 via a link mechanism 62. The potentiometer 64 detects the governor lever angle corresponding to the rotational speed of the engine 41 and inputs it to the controller 60 as the engine control rotational speed Nθ. Is done. The controller 60 also has a potentiometer 65 for instructing a target rotational speed FL corresponding to a manual operation of a fuel lever 65a provided in the cab, and a forward / reverse operation for instructing to switch the forward / reverse switching valve 54 to the N, F, R positions. A changeover switch 66, a parking brake switch 67A, a work brake switch 67B, an auto idle switch 68 that enables an auto idle function, a pilot pressure sensor 69 that detects a traveling pilot pressure, and the auto idle shown in FIG. Each of the pressure switches 17 is connected.
[0024]
The parking brake switch 67A is turned on during parking to bring the parking brake into an operating state. The work brake switch 67B is turned on during work to put the parking brake and the service brake into an operating state. Since neither switch is operated during traveling, the parking brake is released and the service brake is activated by the brake pedal. In accordance with the operating state of these brake switches 67A and 67B and the forward / reverse selector switch 66, the normal operation (hereinafter referred to as normal operation) performed by adjusting the engine speed by the fuel lever 65a, the rotation speed by the traveling and accelerator pedal. It is possible to identify work to be performed by adjustment (hereinafter referred to as work accelerator). FIG. 6 is an identification table, and a work / travel identification circuit 604 of FIG. 7 described later outputs a travel signal and a work accelerator signal according to the logic of FIG.
[0025]
FIG. 7 is a conceptual diagram illustrating details of the controller 60. The function generator 601 outputs a target engine speed Nt for travel proportional to the accelerator pedal depression amount, and the function generator 602 outputs a target engine speed Nda for work proportional to the accelerator pedal depression amount. Outputs a target engine speed Ndl proportional to the operation amount of the fuel lever 65a.
[0026]
That is, the function generators 601 and 602 have the target travel speed Nt determined by functions (rotational speed characteristics) L1 and L2 in which the pilot pressure Pt detected by the travel pilot pressure sensor 69 and the target speed of the engine 41 are associated with each other. The work accelerator target rotational speed Nda is output. The function generator 603 outputs a working lever target rotational speed Ndl determined by a function (rotational speed characteristic) L3 that associates the signal FL depending on the operation amount of the fuel lever 65a with the target rotational speed of the engine 41.
[0027]
A selection switch 605 selects a target rotational speed Nt based on the traveling accelerator target rotational speed characteristic L1 output from the function generator 601 and a target rotational speed Nda output from the function generator 602 based on the working accelerator target rotational speed characteristic L2. select. The selection switch 605 is switched by a switching signal from the work / running identification circuit 604. A switching signal is input to the work / running identification circuit 604 from the forward / reverse switching switch 66, the parking brake switch 67A, and the work brake switch 67B. The work / travel identification circuit 604 outputs a travel signal when the forward / reverse switching switch 66 is switched to either the forward or backward position and both the parking brake switch 67A and the work brake switch 67B are turned off. The selection switch 605 selects the characteristic L1 based on this travel signal. Further, the work / running identification circuit 604 outputs a work accelerator signal when the forward / reverse switch 66 is switched to the neutral position and both the parking brake switch 67A and the work brake switch 67B are turned on. The work / travel identification circuit 604 outputs a work accelerator signal even when the forward / reverse switching switch 66 is switched to the neutral position, the parking brake switch 67A is on, and the work brake switch 67B is off. The selection switch 605 selects the characteristic L2 based on this work accelerator signal. The target rotational speed selected by the selection switch 605 is input to the maximum value selection circuit 606 and compared with the target rotational speed Ndl by the fuel lever characteristic L3 output from the function generator 603. The maximum value selection circuit 606 selects the larger one of the two inputs.
[0028]
The characteristics L1 to L3 will be described in detail with reference to FIG. The characteristic L1 is a target rotation speed characteristic suitable for traveling depending on the depression amount of the accelerator pedal 51, and the characteristic L2 is a target rotation speed characteristic suitable for work depending on the depression amount of the accelerator pedal 51. The work refers to excavation work using a work attachment. The characteristic L1 has a higher target rotational speed than L2, that is, has a steeper slope. The idle speed Ntid and the maximum rotational speed Ntmax of the characteristic L1 are higher than the idle rotational speed Ndid and the maximum rotational speed Ndamax of the characteristic L2, respectively. Is set. The characteristic L3 is a working rotational speed characteristic suitable for work depending on the operation amount of the fuel lever 65a. The characteristics L2 and L3 have the same inclination, that is, the amount of change in the engine speed with respect to the operation amount, and the idle speed Ndid and the target speed Ndmax for full operation are also made equal.
[0029]
In FIG. 7, the target set rotational speed Ny output from the maximum value selection circuit 606 is input to the servo control unit 608 via the changeover switch 607. The changeover switch 607 is switched by the output from the auto idle switching circuit 610, and either the auto idle target rotational speed Nai from the auto idle rotational speed generating circuit 611 or the above-described target set rotational speed Ny is used as the rotational speed command value Nin. Output. The auto idle switch circuit 610 receives the auto idle switch 68, the auto idle pressure switch 17, the traveling pilot pressure sensor 69, and the target set rotational speed Ny from the maximum value selection circuit 606, respectively. Is switched.
[0030]
When the rotational speed command value Nin is output from the changeover switch 607, the rotational speed command value Nin is compared with the control rotational speed Nθ corresponding to the displacement amount of the governor lever detected by the potentiometer 64 by the servo control unit 608. In accordance with the procedure shown in FIG. 9, the pulse motor 63 is controlled so that they match.
[0031]
In FIG. 9, first, at step S21, the rotational speed command value Nin and the control rotational speed Nθ are read, and the process proceeds to step S22. In step S22, the result of Nθ−Nin is stored in the memory as a rotational speed difference A, and in step S23, it is determined whether | A | ≧ K using a predetermined reference rotational speed difference K. If the determination is affirmative, the routine proceeds to step S24, where it is determined whether or not the rotational speed difference A> 0. If A> 0, the control rotational speed Nθ is greater than the rotational speed command value Nin, that is, the control rotational speed is greater than the target rotational speed. Therefore, in order to decrease the engine speed, a signal for instructing motor reverse rotation is output to the pulse motor 63 in step S25. As a result, the pulse motor 63 rotates in the reverse direction and the rotational speed of the engine 41 decreases.
[0032]
On the other hand, if A ≦ 0, the control rotational speed Nθ is smaller than the rotational speed command value Nin, that is, the control rotational speed is lower than the target rotational speed. Therefore, in order to increase the engine rotational speed, a signal for instructing motor forward rotation in step S26. Is output. As a result, the pulse motor 63 rotates forward and the rotational speed of the engine 41 increases. If step S23 is negative, the process proceeds to step S27 to output a motor stop signal, whereby the rotational speed of the engine 41 is held at a constant value. When steps S25 to S27 are executed, the process returns to the beginning.
[0033]
FIG. 10 is a flowchart showing the auto idle switching circuit 610 as software. In step S21, it is determined whether the vehicle is traveling, working, or working accelerator. If it is work, in step S22, it is determined whether or not the condition of auto-idle during work is satisfied. The conditions are as follows.
(1) The auto idle switch 68 is turned on.
(2) All operating levers are neutral for a predetermined time (for example, 4 seconds or more).
(3) The rotation speed target value Ny is constant (no rotation speed fluctuation).
[0034]
If it is determined in step S21 that the vehicle is traveling or a work accelerator, the process proceeds to step S23. In step S23, it is determined whether or not the conditions for auto-idle during work acceleration and travel are satisfied. The conditions are as follows.
(1) The auto idle switch 68 is turned on.
(2) All operating levers are neutral for a predetermined time (for example, 4 seconds or more).
(3) The rotation speed target value is constant (no rotation speed fluctuation).
(4) The accelerator pedal 51 is not operated (not operated).
[0035]
If it is determined in step S22 that the auto-idle condition at the time of work is satisfied, or if it is determined in step S23 that the auto-idle condition at the time of traveling and work accelerator is satisfied, the auto-idle condition is determined in step S24. The idle switch 607 is switched to the auto idle side A. On the other hand, if it is determined in step S22 that the auto-idle condition during work is not satisfied, or if it is determined in step S23 that the auto-idle condition during travel and work accelerator is not satisfied, step S25 is performed. The automatic idle switch 607 is switched to the set rotational speed side B at.
[0036]
The operation of the motor speed controller configured as described above will be described more specifically. In FIG. 7, during traveling, the selection switch 605 selects the target rotational speed Nt set by the target rotational speed characteristic L1 by the work / running identification circuit 604. Since the fuel lever 65a is fixed at the minimum operation position during traveling, the target set speed Ny output from the maximum value selection circuit 606 is the target speed Nt based on the characteristic L1. If the above-described auto-idle condition is satisfied, the changeover switch 607 is switched to the contact A side by a signal from the auto-idle switching circuit 610, and the auto-idle target speed Nai output from the auto-idle speed generation circuit 611. Is output to the servo control circuit 609 as the rotational speed command value Nin. If the above-described auto-idle condition is not satisfied, the changeover switch 607 is switched to the contact B side, so that the target set rotational speed Ny output from the maximum value selection circuit 606 is sent to the servo control circuit 609 as a rotational speed command. Output as the value Nin.
[0037]
Next, when the fuel lever 65a is set to the minimum operation position during work and the engine speed is adjusted by the accelerator pedal 51, in other words, the work accelerator will be described. At the time of work acceleration, the work / travel identification circuit 604 causes the selection switch 605 to select the target speed Nda set by the target speed characteristic L2. Since the fuel lever 65a is fixed at the minimum operating position, the target set speed Ny output from the maximum value selection circuit 606 is the target speed Nda based on the characteristic L2. If the auto-idle condition is satisfied, the auto-idle selector switch 607 is switched to the contact A side, so that the auto-idle target rotational speed Nai is sent to the servo control circuit 608 as the rotational speed command value Nin as in the case of traveling. If the auto idle condition is not satisfied, the target set rotational speed Ny selected by the maximum value selection circuit 606 is output to the servo control circuit 609 as the rotational speed command value Nin. In this case, when the depression of the accelerator pedal 51 is detected, the reduction of the engine speed by auto-idle is prohibited. Therefore, if the accelerator pedal 51 is depressed during the work accelerator, all of the work operation levers are operated. Even if the engine is not operated for a predetermined time, for example, for 4 seconds, the engine speed is not reduced to the idle speed Nai, and the feeling of strangeness is eliminated.
[0038]
A case where the engine speed is adjusted by the fuel lever 65a during the operation will be described. During work, the work / running identification circuit 604 causes the selection switch 605 to select the target rotational speed Ndl set by the target rotational speed characteristic L2. The function generator 603 outputs a target rotational speed Ndl corresponding to the operation amount of the fuel lever 65a. The target rotational speed Nda output from the selection switch 605 is the idle rotational speed Ndid unless the accelerator pedal 51 is operated, and the target set rotational speed Ny output from the maximum value selection circuit 606 is the target rotational speed Ndl according to the characteristic L3. is there. If the auto-idle condition is satisfied, the auto-idle target rotational speed Nai is output to the servo control circuit 608 as the rotational speed command value Nin in the same manner as when traveling. If the auto-idle condition is not satisfied, the maximum value is selected. The target set rotational speed Ny selected by the circuit 606 is output to the servo control circuit 608 as the rotational speed command value Nin.
[0039]
Thus, according to this embodiment, during normal operation in which the engine speed is adjusted by the fuel lever 65a, and during work acceleration in which the work is performed by adjusting the engine speed by the accelerator pedal during traveling. Accordingly, the auto-idle condition is switched, and the auto-idle function is prohibited when the depression of the accelerator pedal 51 is detected. Therefore, if the accelerator pedal 51 is depressed during the work accelerator, the operation lever of the work Even if all of them are not operated for a predetermined time, the engine speed is not reduced to the idle speed, and there is no sense of incongruity. Further, the engine speed is adjusted according to the signal of the pressure sensor 69 for detecting the accelerator pedal depression amount, and the operation / non-operation of the accelerator pedal 51 is determined based on the pressure according to the accelerator pedal depression amount. Therefore, it is not necessary to provide a dedicated detection means, and the cost can be reduced.
[0040]
In the above embodiment, the example in which the engine target speed is set according to the operation amount of the accelerator pedal or the fuel lever has been shown. However, the present invention is also applied to the case where the engine target speed is set by an up / down switch. be able to. Further, the present invention can be similarly applied to a hydraulic traveling vehicle other than a wheeled hydraulic excavator.
[0041]
In the above embodiment, the operation lever BL and the like are the operation lever means BL, the pulse motor 63 and the like are the rotation speed adjustment means, and the auto idle switching circuit 610 and the auto idle switching switch 607 are the rotation speed reduction means and the prohibition means 610. The traveling pilot pressure sensor 69 constitutes the pedal detection means 69, and the pressure switch 17 constitutes the lever detection means 17.
[0042]
【The invention's effect】
  As described above, according to the present invention, the following effects can be obtained.The
When workingThe auto-idle condition is switched according to the time of traveling and working accelerator, so that appropriate conditions can be set individually for working and traveling and working accelerator, respectively, and a highly versatile auto-idling function can be added. Can do.
  Also, when the accelerator pedal depression is detected, the reduction of the engine speed by auto-idle is prohibited, so if the accelerator pedal is depressed during the work accelerator, all the operation levers are operated for a predetermined time. Even if the state of not being continued continues, the motor speed is not reduced to a predetermined speed, and there is no sense of incongruity.
  In particular, as in the invention of claim 3, when adjusting the engine speed according to the amount of depression of the accelerator pedal, the operation / non-operation of the accelerator pedal is determined based on the detected amount of depression of the accelerator pedal. There is no need to provide a dedicated detection means, and the cost can be reduced.
[Brief description of the drawings]
FIG. 1 is an overall hydraulic circuit diagram of a wheeled hydraulic excavator according to an embodiment.
FIG. 2 is a circuit diagram showing details of the traveling hydraulic circuit of FIG.
FIG. 3 is a diagram showing a boom pilot circuit in a working pilot hydraulic circuit.
FIG. 4 is a diagram showing a circuit for detecting operation / non-operation of the operation lever by auto idle.
FIG. 5 is a diagram illustrating a control circuit that controls the engine speed.
FIG. 6 is a diagram for explaining logic for identifying normal work, running, and work accelerator
7 is a diagram for explaining the details of the control circuit shown in FIG. 5;
FIG. 8 is a graph illustrating a rotational speed characteristic set by an accelerator pedal and a fuel lever
FIG. 9 is a flowchart showing a control procedure of engine speed.
FIG. 10 is a flowchart for explaining details of an auto idle switching circuit;
[Explanation of symbols]
10, 20: Variable displacement hydraulic pump 10A: Pilot pump
11-14, 21-25: Control valve
17: Pressure switch for auto idle 31: Hydraulic motor for traveling
41: Engine 51: Accelerator pedal
60: Controller 63: Pulse motor
65: Potentiometer 65a: Fuel lever
67: Brake switch 68: Auto idle switch
601 to 603: Function generator 604: Work / travel identification circuit
607: Changeover switch 610: Auto idle switching circuit
611: Auto idle speed generation circuit

Claims (3)

A variable displacement hydraulic pump driven by a prime mover;
A traveling hydraulic motor driven by pressure oil discharged from the variable displacement hydraulic pump;
A plurality of working hydraulic actuators driven by pressure oil discharged from the variable displacement hydraulic pump;
An accelerator pedal for adjusting the rotational speed of the traveling hydraulic motor;
A rotational speed adjusting means for adjusting a rotational speed of the prime mover according to an operation amount of one of a fuel lever and the accelerator pedal;
Operating lever means for operating each of the plurality of working hydraulic actuators;
Prime mover rotational speed reduction means for reducing the rotational speed of the prime mover to a predetermined low rotational speed when a predetermined auto idle condition is established;
A first operation performed by adjusting the rotational speed by the fuel lever; a second operation performed by adjusting the rotational speed by the accelerator pedal; Prepared,
The auto-idle condition of the first work includes that all of the operation lever means are in a neutral state for a predetermined time or more even when the fuel lever is operated , and the auto-idle condition of the second work and traveling Is a hydraulic traveling vehicle characterized in that all of the operating lever means are non-operating and the accelerator pedal is not operated. In the hydraulic traveling vehicle of claim 1,
Further comprising an operation lever detecting means for detecting an operation of the operation lever means by the presence or absence of an operation of a control valve for controlling a flow rate and a direction of pressure oil to the working hydraulic actuator,
The hydraulic vehicle according to claim 1, wherein the prime mover rotation speed reduction means determines whether the auto idle condition is satisfied according to the operation of the operation lever detected by the operation lever detection means. In the hydraulic traveling vehicle of claim 1,
Further comprising pedal detection means for detecting an operation amount of the accelerator pedal;
The rotational speed adjusting means adjusts the prime mover rotational speed according to the operation amount of the accelerator pedal detected by the pedal detecting means,
The hydraulic vehicle according to claim 1, wherein the prime mover rotational speed reduction means determines whether or not the auto idle condition is satisfied according to an operation of the accelerator pedal detected by the pedal detection means.

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