JP4073191B2 - Working machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is provided with an accelerator lever for setting the number of revolutions of the engine and work detection means for detecting whether or not the work hydraulic actuator is in a work state, and the work detection means detects the work state. When operating the electric engine speed control device so that the speed set by the accelerator lever is at the same time, and when the work detection means does not detect the work state, the engine speed is prioritized over the setting by the accelerator lever. The present invention relates to a working machine such as a backhoe provided with a control device for operating the engine speed governor so as to be lowered.
[0002]
[Prior art]
Conventional working machines such as this type of backhoe are configured to immediately stop the power supply when there is a power supply stop operation to the engine governor.
[0003]
[Problems to be solved by the invention]
However, according to the above conventional technique, there is no problem if the power supply is stopped after the accelerator lever is returned from the set rotational speed position (generally, the maximum rotational speed position) to the idling position. In some cases, the accelerator lever is returned to the idling position after the power supply stop operation is performed. In such a case, when the engine is started by operating the power supply next time, the engine speed control device is not returned to the idling state and is in the set speed state, so the engine rotates from the beginning at the set speed. Resulting in. This is disadvantageous in terms of engine durability.
[0004]
An object of the present invention is to promote engine start at idling speed.
[0005]
[Means for Solving the Problems]
The working machine according to the first aspect of the present invention is characterized in that an accelerator lever for setting the engine speed and a work detecting means for detecting whether or not the working hydraulic actuator is in a working state are provided. When detecting that the detecting means is in the working state , the electric engine speed control device is operated so that the number of revolutions set by the accelerator lever is reached, and it is detected that the working detecting means is not in the working state . A work machine provided with a control device for operating the engine speed control device so as to reduce the engine speed in preference to the setting by the accelerator lever, and the operation of stopping power supply to the engine speed control device is performed In this case, the power supply is stopped after the power supply to the engine governor is maintained for a set time.
[0006]
The working machine of the present invention according to claim 2 is characterized in that, in the working machine according to the present invention according to claim 1, the working detection means is in a working state when at least one of a plurality of hydraulic actuators is in a working state. It is a means to detect that it is not in a working state when all of the hydraulic actuators are not in a working state.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1, a backhoe, which is an example of a work machine, includes a swivel base 5 equipped with an engine 3 and an operation unit 4 on an upper part of a travel machine base 2 equipped with a pair of left and right crawler type travel devices 1L and 1R. A front device 9 which is mounted so as to be able to swivel all around the vertical axis X1 and which has a boom 6, an arm 7 and a bucket 8 sequentially pivotally connected to the front of the swivel 5 is provided. Is equipped with a soil removal board 10 for dozer work.
[0008]
The left and right traveling devices 1L and 1R are driven forward and backward by traveling hydraulic motors ML and MR, respectively, and the swivel 5 is driven to turn left and right by a turning hydraulic motor MT.
Each of the boom 6, arm 7, and bucket 8 of the front device 6 is driven by a boom cylinder C 1, arm cylinder C 2, and bucket cylinder C 3, and the entire front work device 9 is connected to the swivel base 3 by a swing cylinder C 4. Thus, it is driven to swing left and right around the vertical axis X2. The earth removal plate 10 is driven up and down by a dozer cylinder C5. The boom cylinder C1, arm cylinder C2, bucket cylinder C3, swing cylinder C4, and dozer cylinder C5 are hydraulic cylinders.
[0009]
As shown in FIGS. 2 and 3, in the hydraulic circuit that drives the various hydraulic actuators described above, V1 is a control valve for turning that controls the supply of pressure oil to the turning hydraulic motor MT, and V2 is A control valve for left travel that controls the supply of pressure oil to the left travel hydraulic motor ML, and V3 is a control valve for right travel that controls the supply of pressure oil to the hydraulic motor MR for right travel, and V4. Is a control valve for the dozer that controls the supply of pressure oil to the dozer cylinder C5, V5 is a control valve for the arm that controls the supply of pressure oil to the arm cylinder C2, and V6 is the boom cylinder C1 B7 is a boom control valve for controlling the pressure oil supply to the bucket, and V7 is a bucket for controlling the pressure oil supply to the bucket cylinder C3. A control valve, V8 is a control valve for the swing controlling the pressure oil supply to the swing cylinder C4, V9 is a control valve for the auxiliary working.
[0010]
The left and right traveling control valves V2 and V3 are manually operated types in which the spool is directly switched by the left and right traveling levers 13 provided in the control tower 12 in front of the driver's seat 11, respectively. The control valve V4, the control valve V8 for swing, and the control valve V9 for auxiliary work are manually operated types in which the spool is directly operated by lever operation or pedal operation. The control valve V5, the boom control valve V6, and the bucket control valve V7 are supplied from pilot valves PV1 and PV2 that are operated by a pair of left and right working levers 14 disposed on the control tower 12 so as to be able to perform a cross operation. A hydraulic pilot operated type is operated by a pilot pressure to an opening degree corresponding to a lever operation amount. The valve block group of the control valves V1 to V9 is connected in parallel with the inlet block B1 and the outlet block B2 and connected to each other by an internal oil passage.
[0011]
A pressure oil supply unit 15 includes a main pump P1 for work and a pilot pump P2 for supplying pilot pressure, and is driven by the engine 3. The main pon P1 is a variable displacement type that can change the discharge amount by changing the angle of the swash plate. After the discharge oil is supplied to the inlet block B1 through the oil passage a, each control valve V1 is used. To V9. The pilot pump P2 is a constant capacity gear pump, and the discharge pressure thereof is supplied as the pilot original pressure of the pilot valves PV1 and PV2 via the oil passage b.
[0012]
The backhoe includes an auto idling control system that automatically operates the accelerator device of the engine 3.
As shown in FIG. 3, the auto-idling control system determines whether or not the accelerator lever 24 for setting the rotational speed of the engine 3 installed in the operation unit 4 through a potentiometer and the working hydraulic actuator A are in a working state. An engine speed control device B including a governor 21 of the engine 3 and an electric actuator 22 such as an electromagnetic solenoid or a motor for operating the governor 21 of the engine 3, and the rotation speed and the work set by the accelerator lever 24. And a control device 23 for operating the engine speed control device B based on the detection result by the detection means.
[0013]
The hydraulic actuator A includes the traveling hydraulic motor ML, MR, turning hydraulic motor MT, boom cylinder C1, arm cylinder C2, bucket cylinder C3, swing cylinder C4, and dozer cylinder C5.
[0014]
The work detecting means detects that one of the plurality of hydraulic actuators A is in a working state and detects that it is not in a working state when all of the hydraulic actuators A are not in a working state. Means for determining that the control valves V1 to V9 are not in a working state when the control valves V1 to V9 are in a neutral position, and for determining that they are in a working state when the control valves V1 to V9 are in other positions.
[0015]
Specifically, as shown in FIG. 2, the control valves V1 to V9 are connected in series to the respective spools, and the upstream thereof is branched through the oil passage b of the pilot pump P2 to the oil passage h via a throttle s. And a pressure switch 25 for detecting a valve operation detection pilot oil passage g connected downstream to the tank T and detecting the pressure of the valve operation detection pilot oil passage g and outputting the detected pressure to the control device 23. Configured.
That is, in a state where all of the control valves V1 to V9 are in a neutral state, the pilot oil passage g for detecting the valve operation is communicated with the tank T, and the pressure thereof is reduced to almost zero. If any one of them is operated, the valve operation detection pilot oil passage g is disconnected from the tank T, and the pressure in the valve operation detection pilot oil passage g rises close to the original pressure of the pilot pump P2. Thus, it is determined whether or not the control valves V1 to V9 are operated by detecting whether or not the pressure is established in the valve operation detection pilot oil passage g with the pressure switch 25. .
[0016]
The control device 23 is a microprocessor, and is set by the accelerator lever 24 when the work detection means detects a work state, that is, when the pressure switch 25 detects a high pressure. When the electric actuator 22 of the engine speed control device B is operated so as to achieve a high rotational speed while the work detection means does not detect the work state, that is, when the pressure switch 25 does not detect high pressure, the accelerator It has a function of operating the electric actuator 22 of the engine governor B so that the rotational speed of the engine 3 is reduced to idling in preference to the setting of the lever 24.
[0017]
Moreover, in this backhoe, when there is a power supply stop operation to the engine speed control device B, that is, the electric actuator 22, the power supply is stopped after maintaining the power supply to the engine speed control device B for a set time. It is configured as follows. Specifically, an electromagnetic maintenance switch 28 is connected to the power supply line 26 to the engine governor B in parallel with a key switch 27 that performs a power supply stop operation, and the key switch 27 is turned off. A power supply sensor 29 for detecting (power supply stop operation) is provided, and a timer 30 for energizing the maintenance switch 28 until the set time elapses from the detection based on the detection of the power supply sensor 29 in the control device 23 is provided. Include.
[0018]
Accordingly, by setting the set time based on the time until the accelerator lever 24 is operated to the idle ring position after the key switch 27 is turned off, the accelerator is operated after the key switch is turned off as the engine stop operation mode. Even when the lever 24 is returned to the idling position, the power supply continues for a set time after the key switch 27 is turned off, so that the engine governor B returns to the idling state, and then When the engine is started with the key switch 27 turned on, the engine 3 can be started by idling.
[0019]
[Another embodiment]
In the above embodiment, the backhoe is shown as the work machine, but the present invention can be applied to various work machines.
【The invention's effect】
After the operation of returning the accelerator lever to the idling position following the power supply stop operation, the set time is set based on the time until the engine governor operates in the idling state. Even if the accelerator lever is returned to the idling position after the stop operation, the engine governor is in the idling state when the engine is started by operating the power supply after that. By appropriately performing the return operation, it is possible to prevent the engine from starting at a high speed from the beginning.
Therefore, it is possible to promote a good engine start at the idling speed.
[Brief description of the drawings]
[Fig. 1] Side view of backhoe [Fig. 2] Hydraulic circuit diagram [Fig. 3] Control block diagram [Explanation of symbols]
3 Engine 24 Accelerator lever A Hydraulic actuator B Engine speed control device 23 Control device

Claims (2)

An accelerator lever for setting the rotational speed of the engine, a hydraulic actuator for working is provided with operation detection means for detecting whether or not in a working state, when the operation detection means detects that it is in working state Operate the electric engine speed control device so that the engine speed is set by the accelerator lever, and when the work detection means detects that the engine is not in the working state , the engine speed is prioritized over the setting by the accelerator lever. A work machine provided with a control device for operating the engine speed control device so as to reduce the power supply to the engine speed control device for a set time when there is a power supply stop operation to the engine speed control device. A work machine configured to stop power supply after maintaining the supply. The work detection means is means for detecting that one of a plurality of hydraulic actuators is in a working state and detecting that the working state is not in a working state when all of the hydraulic actuators are not in a working state. The work machine according to claim 1.

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