JP2008267490A - Warm-up device for construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely prevent the malfunction of a working machine during warm-up operation. <P>SOLUTION: This warm-up device for a construction machine comprises a lock detecting means, a pressure sensor 23 as a lever condition detecting means, an operating oil temperature sensor 22, and a controller 20 as a temperature increasing means. The lock detecting means detects the condition of a lock lever 6 to disable the operation of the working machine. The pressure sensor 23 detects the operated condition of a working machine operating lever 5. The operating oil temperature sensor 22 detects the temperature of operating oil. The temperature increasing means executes treatment to increase the temperature of the operating oil when the on-operated condition of the lock lever 6 is detected, the neutral condition of the working machine operating lever 5 is detected, and the temperature of the operating oil is detected to be lower than a first set temperature. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a warming-up device for a construction machine, and more particularly to a warming-up device for a construction machine for warming up hydraulic fluid of a construction machine having a working machine.

  In a construction machine such as a hydraulic excavator having a hydraulic working machine, when starting the working machine at a low temperature, the hydraulic oil temperature is low and the viscosity is high. It may not work. Further, even after the hydraulic oil temperature rises after the engine is started, if the idling state in which work is not performed continues for a long time, the hydraulic oil cools during that time, particularly in a low temperature environment. In such a case, warm-up operation is required at the time of re-operation, and work efficiency is reduced.

  Therefore, as disclosed in Patent Document 1, when the working oil temperature is equal to or lower than a predetermined temperature when the work machine is not operated after the engine is started, the discharge amount of the hydraulic pump is temporarily increased to reduce the working oil temperature. Techniques to raise are proposed.

Patent Document 2 discloses that in a construction machine, a warm-up operation is performed by returning a hydraulic pilot circuit from a discharge circuit of a hydraulic pump to a tank drain through a pilot operation valve. A technique for preventing malfunction of a work machine during machine operation is shown. In the apparatus shown in this document, during warm-up operation, an electromagnetic switching valve provided between the hydraulic pump and the pilot operation valve is connected to an electric circuit of a lock lever for locking the operation of the work machine. It is related. Therefore, in this apparatus, the electromagnetic switching valve is switched only in a state where the actuator of the work machine is locked, and the warm-up operation can be performed. For this reason, in this apparatus, even if an operation for erroneously entering the normal operation state is performed in a state where the warm-up operation is performed, the work machine does not operate and the malfunction can be prevented.
Japanese Patent Laid-Open No. 2003-239907 JP 2003-184827 A

  In the apparatus described in Patent Document 2, since the work implement does not operate even if an operation for entering the normal operation state is mistakenly performed while the warm-up operation is performed, the malfunction can be prevented. That is, even if the operating lever of the work implement is accidentally moved from the neutral state to the working position, the warm-up operation is performed in a state where it is locked by the lock lever, so that it is possible to prevent malfunction during the warm-up operation. it can.

  However, if the driver does not notice that the operating lever of the work implement is in the work position when unlocking the lock lever due to the completion of warm-up operation, etc., work simultaneously with the unlocking of the lock lever. The machine may malfunction.

  An object of the present invention is to reliably prevent malfunction of a work machine during warm-up operation.

  A warming-up device for a construction machine according to a first invention is a device for warming up hydraulic fluid of a construction machine having a working machine driven by a hydraulic actuator, and includes a lock detection means, a lever state detection means, And a hydraulic oil temperature detecting means and a temperature raising means. The lock detection means detects an on / off state of a lock mechanism for disabling the work machine. The lever state detection means detects the operation state of the operation lever of the work implement. The hydraulic oil temperature detection means detects the hydraulic oil temperature. The temperature raising means detects that the lock mechanism is in the on state by the lock detecting means, detects that the operation lever is in the neutral state by the work lever state detecting means, and detects the operating oil temperature by the operating oil temperature detecting means. When it is detected that the temperature is lower than the first set temperature, a process for raising the hydraulic oil temperature is executed.

  Here, when the lock mechanism is in the on state and the operation lever of the work implement is in the neutral state, the warm-up is executed when it is detected that the hydraulic oil temperature is lower than the first set temperature. For this reason, for example, when the work implement operation lever is moved from the neutral position and enters the operation position when the lock mechanism is in the ON state, the warm-up is not executed. Therefore, it is possible to prevent the work machine from operating erroneously when the lock mechanism is released at the end of warm-up.

  According to a second aspect of the present invention, there is provided a warming-up device for a construction machine further comprising an automatic warming-up switch capable of instructing from the outside whether or not a temperature raising process is to be executed by the temperature raising means. I have.

  In this apparatus, the warm-up process is performed when an instruction to perform automatic warm-up is given by the switch.

  A warming-up device for a construction machine according to a third invention is the device according to the first or second invention, further comprising a rotation speed detection means for detecting the engine rotation speed, and the rotation speed detection means has a predetermined rotation speed detection means. When the engine speed is lower than the predetermined engine speed, control is performed to increase the hydraulic oil temperature after performing control for setting the engine speed to a predetermined speed.

  For example, at the time of idling, the engine speed is suppressed to the minimum speed, and may be too low as the speed for raising the temperature of the hydraulic oil. Therefore, if the engine speed is too low during warm-up, the warm-up process is executed after increasing the engine speed to a predetermined speed. For this reason, efficient warm-up processing can be performed.

  A warming-up device for a construction machine according to a fourth invention is the device according to any one of the first to third inventions, wherein the temperature raising means performs the process for raising the hydraulic oil so that the hydraulic oil temperature is first. When the second set temperature higher than the set temperature is exceeded, the process for raising the temperature is stopped.

  When the hydraulic oil temperature at which the warm-up process is started and the hydraulic oil temperature at which it is stopped are the same, hunting may occur. In view of this, this apparatus prevents the occurrence of hunting by providing a difference between the temperature for starting the treatment and the temperature for stopping, that is, by providing hysteresis.

  A warming-up device for a construction machine according to a fifth invention is the device according to any one of the first to fourth inventions, wherein the hydraulic actuator is supplied with operating hydraulic pressure by a hydraulic pump driven by an engine of the construction machine. The temperature raising means increases the amount of oil discharged from the hydraulic pump to raise the temperature of the hydraulic oil.

  Here, the temperature of the hydraulic oil can be increased by increasing the amount of oil discharged from the hydraulic pump.

  According to a sixth aspect of the present invention, there is provided a warming-up device for a construction machine according to any one of the first to fourth aspects, wherein the hydraulic actuator is supplied with operating hydraulic pressure by a hydraulic pump driven by an engine of the construction machine. A closed circuit for returning the oil discharged from the hydraulic pump to the tank when the hydraulic actuator is not operated, and the temperature raising means raises the hydraulic pressure of the closed circuit to raise the temperature of the hydraulic oil.

  A warming-up device for a construction machine according to a seventh invention is the device according to the sixth invention, wherein the temperature raising means forces a phenomenon similar to the phenomenon when the discharge amount of the hydraulic pump decreases when the hydraulic actuator is not operated. Artificially generated means for increasing the hydraulic pressure of the closed circuit and increasing the discharge oil amount of the hydraulic pump to raise the temperature of the hydraulic oil.

  When the work implement operating lever is in the neutral position, the load of the hydraulic actuator does not change. Therefore, in principle, the discharge amount of the hydraulic pump cannot be controlled except for a hydraulic pump that can control the discharge amount by electronic control.

  Therefore, in the present invention, even when the hydraulic actuator is inactive, a phenomenon similar to a phenomenon in which the load is increased by operation, that is, the discharge amount of the hydraulic pump is decreased is forcibly generated. Yes. That is, the phenomenon that the hydraulic actuator is actuated to increase the load is simulated.

  The amount of oil discharged from the hydraulic pump increases by the pseudo control process as described above. For this reason, as the closed circuit hydraulic pressure increases, the amount of discharged oil increases, and warm-up processing can be performed efficiently.

  In the present invention as described above, it is possible to reliably prevent malfunction of the work machine during the warm-up operation.

[First Embodiment]
<Overall configuration>
FIG. 1 is a block diagram showing the configuration of a warm-up device for a construction machine according to an embodiment of the present invention. A construction machine shown in FIG. 1 includes an engine 1, an electronically controlled variable displacement pump 2 driven by the engine 1, a hydraulic cylinder (hydraulic actuator) 3 for a work machine driven by the pump 2, a pump 2 and a main valve 4 for control provided between the hydraulic cylinder 3 and the hydraulic cylinder 3. Further, the construction machine is provided with a work machine operation lever 5 for operating the work machine, a lock lever 6 for preventing the work machine from operating, and an automatic warm-up switch 7. . These levers 5 and 6 and the automatic warm-up switch 7 are both provided near the driver's seat. The automatic warm-up switch 7 is a switch for starting automatic warm-up control so that the temperature of the hydraulic oil is maintained at a predetermined temperature or higher. The engine 1 is provided with a governor 1a for controlling the engine speed, and the hydraulic pump 2 is provided with a servo mechanism 2a for controlling the tilt angle of the swash plate.

  On the discharge side of the pump 2, return oil passages 12 and 13 are provided that branch from the hydraulic pressure supply passage 10 to the main valve 4 and return the working oil to the tank 11. The return oil passage 12 is provided with a pressure control relief valve 14, and the return oil passage 13 is provided with an unload valve 15. A closed circuit is formed by the hydraulic pump 2, the relief valve 14, the tank 11, and the oil passage 12 provided therebetween.

<Warming device>
Next, a control circuit related to a warming-up device for warming up the hydraulic oil will be described. This construction machine has a controller 20 composed of a microcomputer. The controller 20 includes a signal S1 indicating the operation position of the work machine operation lever 5, a signal S2 indicating the lever position of the lock lever 6, and an automatic operation. An automatic warm-up start signal S3 from the warm-up switch 7, a signal S4 from the hydraulic oil temperature sensor 22, and a signal S5 indicating the engine speed from the engine speed sensor 21 are input. The signal S1 indicating the operation position of the work implement operation lever 5 is an output signal of the pressure sensor 23 that detects the pressure of the operation portion of the main valve 4.

  The controller 20 inputs the above signals, outputs a signal S6 for controlling the engine speed to the engine governor 1a, and controls the pump displacement by controlling the swash plate angle of the pump 2. The signal S7 is output to the servo mechanism 2a.

<Warm-up control>
Below, the automatic warm-up control of the controller 20 is demonstrated with reference to the flowchart of FIG. As described above, the automatic warm-up control is a control process for maintaining the temperature of the hydraulic oil at a predetermined temperature or higher, and is executed while the engine is rotating.

  First, in step S1, it waits for the automatic warm-up switch 7 to be pressed. When the automatic warm-up switch 7 is pressed, the process proceeds from step S1 to step S2.

  In step S2, it is determined whether or not the lock lever 6 is in a locked state. In step S3, it is determined whether or not the work implement operating lever 5 is in a neutral state. When the lock lever 6 is not in the locked state, that is, when the operation of the work machine is permitted, the process proceeds from step S2 to step S4, and the work machine operation lever 5 is operated to the work position instead of the neutral state. In this case, the process proceeds from step S3 to step S4. In step S4, the operator is warned that the lock lever 6 is not locked or the work implement operation lever 5 is not neutral, and the process returns to step S1.

  As described above, even when the automatic warm-up switch 7 is pressed, it is confirmed that the lock lever 6 is in the locked state and the work implement operating lever 5 is in the neutral state. Executed. If the automatic warm-up switch 7 is pressed and no processing is executed and a warning is displayed, the operator confirms the state of the lock lever 6 and the position of the work implement operation lever 5 and locks them. It is necessary to press the automatic warm-up switch 7 again in the state and neutral state.

  When the automatic warm-up switch 7 is pressed, if the lock lever 6 is in the locked state and the work implement operating lever 5 is in the neutral state, the process proceeds from step S2, S3 to step S5. In step S5, it is determined whether or not the hydraulic oil temperature is lower than a preset temperature A. When the hydraulic oil temperature is equal to or higher than the set temperature A, it is not necessary to raise the temperature of the hydraulic oil. Specifically, a signal S6 is output to the engine governor 1a so that the engine speed is maintained in an idling state, and a signal S7 for setting the pump 2 to the minimum capacity is output to the servo mechanism 2a.

  The hydraulic oil temperature is detected at a predetermined cycle. For example, when the idling operation continues for a long time under a low temperature condition, the oil temperature becomes lower than the set temperature A. In such a case, the process proceeds from step S5 to step S6. In step S6, it is determined whether the engine speed is lower than a preset speed N. When the engine speed is lower than the engine speed N, warm-up is not performed efficiently. Therefore, the process proceeds from step S6 to step S7, and a signal S6 for setting the engine engine speed to a speed higher than the engine speed N is set. Output to engine governor 1a. If the engine speed is equal to or higher than the engine speed N, step S7 is skipped and the process proceeds to step S8.

  In step S8, a signal S7 for increasing the capacity of the pump 2 is output to the servo mechanism 2a. The extent to which the capacity of the pump 2 is increased is determined in advance through experiments and the like in consideration of the environment in which the construction machine is used.

  Next, in step S9, it is determined whether or not the hydraulic oil temperature has become higher than the set temperature B. This set temperature B is set higher than the set temperature A, and the occurrence of a hunting phenomenon is prevented by providing hysteresis. Then, the process of step S8 is executed until the hydraulic oil temperature becomes higher than the set temperature B. When the hydraulic oil is sufficiently warmed up to the set temperature B, the process proceeds to step S10. In step S10, a signal S7 for returning the pump capacity to the minimum capacity is output to the servo mechanism 2a, and the process returns to step S5.

  By executing the above processing, it is possible to prevent malfunction of the work machine and to perform work with an efficient work machine by executing warm-up of the hydraulic oil.

[Second Embodiment]
<Overall configuration>
3 and 4 show a second embodiment of the present invention. In the first embodiment, the electronically controlled variable displacement hydraulic pump 2 is used as the hydraulic pump. However, in this second embodiment, the variable displacement type is a type in which the tilt angle of the swash plate is controlled by a hydraulic servo valve. A hydraulic pump 2 'is used. Other configurations are the same as those of the first embodiment.

<Hydraulic pump and displacement control>
First, as a control method of the hydraulic pump 2 ′, a CLSS (Closed-center Load Sensing System) method is adopted in the second embodiment. In this CLSS system, an LS (load sensing) pressure is detected on the discharge side of the hydraulic pump 2 ′, and the discharge amount of the hydraulic pump 2 ′ is controlled so that the LS pressure becomes constant.

  Therefore, in the second embodiment, as a circuit for controlling the discharge amount of the hydraulic pump 2 ′, an LS valve 30 that senses the work machine load (load of the hydraulic cylinder 3) and controls the discharge amount of the hydraulic pump 2 ′. And a PC valve 31 for controlling the load of the work implement so as not to exceed the engine horsepower, and further, an LS that applies pilot pressure to each of the LS valve 30 and the PC valve 31 in accordance with a command from the controller 20. An electronic switching valve for valve (LS-EPC valve) 32 and an electronic switching valve for PC valve (PC-EPC valve) 33 are provided. In the circuit of FIG. 3, a hydraulic servo valve for controlling the swash plate of the hydraulic pump 2 'is omitted.

  With the above configuration, the discharge amount of the hydraulic pump 2 ′ is controlled according to the load acting on the hydraulic cylinder 3 and the command from the controller 20.

<Warming device>
Moreover, in this 2nd Embodiment, the solenoid valve 34 for canceling the unloading in the unloading valve 15 is provided as a structure for warming up hydraulic fluid. By controlling the electromagnetic valve 34 by the controller 20, the discharge oil of the hydraulic pump 2 'can be returned to the tank 11 via the unload valve 15, and the unload can be canceled (released). Become. Other configurations are the same as those in the first embodiment.

<Warm-up treatment>
Next, the warm-up process of the hydraulic oil will be described using the flowchart of FIG. In the flowchart of the second embodiment shown in FIG. 4, the processing in steps S1 to S7 and step S9 is the same as the processing in the first embodiment.

  That is, in steps SS1 to S7, when the automatic warm-up switch 7 is pressed, it is determined whether or not the lock lever 6 is in a locked state and whether or not the work implement operating lever 5 is in a neutral state. If the lock lever 6 is not in the locked state or the work implement operating lever 5 is not in the neutral state, the operator is warned to that effect and the warm-up process is not executed. When the automatic warm-up switch 7 is pressed, if the lock lever 6 is in the locked state and the work implement operating lever 5 is in the neutral state, whether or not the warm-up is executed depending on the hydraulic oil temperature. To decide. When warming up the hydraulic oil, the engine speed is set to a speed higher than the speed N.

  After executing the same processing as in the first embodiment as described above, the process proceeds to step S10. In step S 10, a signal for closing the unload valve 15 is output to the electromagnetic valve 34. As a result, the oil passage through which the hydraulic oil is returned to the tank 11 via the unload valve 15 is blocked.

  Here, the discharge amount of the hydraulic pump 2 ′ does not increase, but the hydraulic pressure of the closed circuit constituted by the hydraulic pump 2 ′, the main relief valve 4 and the tank 11 rises to the set pressure of the main relief valve. For this reason, the hydraulic oil circulating through this closed circuit has a very small hydraulic pressure when the hydraulic oil is returned through the unload valve. By the processing as described above, the temperature rises as compared with the case where the unload valve 15 is not closed.

  If the hydraulic oil exceeds the set value B by the above processing, the process proceeds from step S9 to step S11. In step S <b> 11, the unload valve 15 is opened, and the hydraulic oil is also returned from the unload valve 15 to the tank 11. As a result, the load of the hydraulic pump 2 'returns to the normal idling state.

  By executing the above processing, it is possible to prevent malfunction of the work machine and to perform work with an efficient work machine by executing warm-up of the hydraulic oil.

[Third Embodiment]
In the second embodiment, the hydraulic pressure is increased by closing the unload valve 15 to increase the temperature of the hydraulic oil. However, the hydraulic oil discharge amount cannot be increased by controlling the swash plate of the hydraulic pump 2 '.

  Therefore, in the third embodiment shown in FIGS. 5 and 6, by controlling the swash plate of the hydraulic pump 2 ', not only the hydraulic pressure is increased, but also the pump discharge amount is increased. As a result, the hydraulic oil can be warmed up in a shorter time. The type and control method of the hydraulic pump 2 'are the same as those in the second embodiment.

  Specifically, in addition to the configuration shown in FIG. 3, an electromagnetic valve 35 for increasing the load of the hydraulic pump 2 ′ (hydraulic pressure of the oil passage 13) is provided. The electromagnetic valve 35 for increasing the load is controlled by the controller 20. Other configurations are the same as those of the second embodiment.

<Warm-up treatment>
In 3rd Embodiment which has the above structure, warming-up of hydraulic oil is performed according to the flowchart shown in FIG. FIG. 6 shows only processing steps S20 to S22 different from those in the second embodiment, and the other steps S1 to S7 and steps S9 and S11 are the same as those in the second embodiment.

  Here, processing similar to that of the second embodiment is executed in steps S1 to S7, and after increasing the engine speed to the set speed in step S7, the process proceeds to step S20. In step S20, the unload valve 15 is closed. As a result, as in the second embodiment, the hydraulic pressure of the closed circuit that circulates through the hydraulic pump 2 ′, the main relief valve 14, and the tank 11 increases, and the hydraulic oil temperature increases. In addition to the above, in the third embodiment, in step S21, the electromagnetic valve 35 for increasing the load is operated to reduce the LS differential pressure. This decrease in the LS differential pressure means that the discharge amount of the hydraulic pump 2 'has decreased. Thereby, in step S22, a command is issued to the PC-EPC valve 33 in order to increase the capacity of the hydraulic pump 2 '.

<Fake processing>
As described above, in the third embodiment, in order to increase the temperature of the hydraulic oil, the LS differential pressure is forcibly decreased to increase the capacity of the hydraulic pump 2 ′. That is, when the work implement operating lever 5 is in the neutral state, the work implement load (load of the hydraulic cylinder) does not change, and therefore the load of the hydraulic pump 2 ′ does not change. That is, the capacity of the hydraulic pump 2 ′ cannot be increased. Therefore, in the present embodiment, the LS differential pressure is forcibly reduced to simulate the work machine load as if it increased. With this simulation, the capacity of the hydraulic pump 2 ′ can be increased even though the work machine operation lever 5 is in the neutral state. Therefore, not only the increase of the hydraulic pressure but also the discharge amount of the hydraulic pump 2 ′ can be increased, and the hydraulic oil can be warmed up efficiently in a short time.

[Fourth Embodiment]
FIG. 7 shows a fourth embodiment of the present invention. In this 4th Embodiment, the control system of hydraulic pump 2 'differs from the 1st-3rd embodiment.

<Configuration for hydraulic pump and capacity control>
An OLSS (Open-center Load Sensing System) system is adopted as a control system for the hydraulic pump 2 'in the fourth embodiment. In this OLSS system, the discharge amount of the hydraulic pump 2 'is controlled in accordance with the stroke of the lever operated by the operator, thereby reducing the amount of excess pressure oil that causes energy loss, thereby saving energy. In this method, a throttle valve that detects the amount of oil is provided, and as the amount of oil that passes through the throttle valve increases, the pressure difference before and after the throttle valve increases. Control the valve etc., and control the servo valve etc. in the direction to increase the pump capacity when the passing flow rate decreases.

  Therefore, in the fourth embodiment, as a circuit for controlling the discharge amount of the hydraulic pump 2 ′, a neutral control valve (NC valve) 40, a cut-off valve (CO valve) 41, a variable torque control valve (TVC) Valve) 42 is connected in series. Further, an EPC valve 43 that applies a pilot pressure to the TVC valve 42 and an electromagnetic valve 44 that operates the cut-off valve 41 are provided. In this embodiment, the unload valve 15 in the first embodiment or the like functions as a jet sensor for load sensing (load detection). Other configurations are the same as the configurations indicated by the same reference numerals in the respective embodiments. Further, a servo valve for operating the swash plate of the hydraulic pump 2 'is omitted.

<Hydraulic pump capacity control>
The displacement control of the hydraulic pump in this embodiment is executed as follows.

  That is, the pressure of the relief valve 15 as a jet sensor and the pressure on the downstream side of the relief valve 15 are respectively input to the NC valve 40, and the NC valve 40 is switched by these differential pressures. Specifically, when the main valve 4 is in the neutral state, the amount of oil drained from the jet sensor relief valve 15 increases, and the NC valve 40 reduces the discharge amount of the hydraulic pump 2 ′ due to the change in the differential pressure caused thereby. Energy loss at the neutral position is reduced.

  On the other hand, when the main valve 4 is operated, no hydraulic oil flows into the jet sensor relief valve 15. When the discharge pressure of the hydraulic pump 2 ′ is lower than the command signal for the engine speed, the discharge amount of the hydraulic pump 2 ′ is increased by the operation of the TVC valve 42 and the CO valve 41. Conversely, when the discharge pressure of the hydraulic pump 2 ′ is higher than the command signal for the engine speed, the TVC valve 42 is switched, and the operation of the TVC valve 42 and the CO valve 41 causes the hydraulic pump 2 ′ to operate. The discharge amount is reduced.

  The CO valve 41 is switched when the discharge pressure of the hydraulic pump 2 'reaches the maximum pressure, and operates to further reduce the flow rate of the maximum pressure.

  As described above, the discharge amount of the hydraulic pump 2 ′ is controlled according to the operation of the main valve 4 and the command from the controller 20.

<Warm-up treatment>
About the warming-up process of hydraulic oil, it is completely the same as the process of the flowchart of FIG. 4 in 2nd Embodiment. That is, when the automatic warm-up switch 7 is pressed, it is determined whether or not the lock lever 6 is in the locked state, and whether or not the work implement operating lever 5 is in the neutral state, and the lock lever 6 is locked. When it is not in the state or when the work machine operation lever 5 is not in the neutral state, the operator is warned to that effect and the warm-up process is not executed. When the automatic warm-up switch 7 is pressed, if the lock lever 6 is in the locked state and the work implement operating lever 5 is in the neutral state, the warm-up is executed according to the hydraulic oil temperature. Specifically, when warming up is performed, a signal for closing the jet sensor relief valve 15 is output to the electromagnetic valve 34, and hydraulic oil is returned to the tank 11 via the jet sensor relief valve 15. Block the road. As a result, the hydraulic pressure in the closed circuit including the hydraulic pump 2 ′ increases, and the hydraulic oil temperature rises.

[Fifth Embodiment]
In the fourth embodiment, the oil pressure is increased by closing the jet sensor relief valve 15 to increase the temperature of the hydraulic oil. However, in this case, it is not possible to increase the discharge amount of the hydraulic oil by controlling the swash plate of the hydraulic pump 2 ′ as in the second embodiment.

  Therefore, in the fifth embodiment shown in FIGS. 8 and 9, by controlling the swash plate of the hydraulic pump 2 ', not only the hydraulic pressure is increased, but also the pump discharge amount is increased. As a result, the hydraulic oil can be warmed up in a shorter time.

  Specifically, in addition to the configuration shown in FIG. 7, an NC line communication electromagnetic valve 45 for making two pressures input to the NC valve 40 the same pressure is provided. The electromagnetic valve 45 is controlled by the controller 20. Other configurations are the same as those in the fourth embodiment.

<Warm-up treatment>
In the fifth embodiment, the warming-up of the hydraulic oil is executed according to the flowchart shown in FIG. FIG. 9 shows only processing steps S30 to S32 that are different from the fourth embodiment (the flowchart shown in FIG. 4), and the other steps S1 to S7 and steps S9 and S11 are the same as those of the fourth embodiment. is there.

  Here, processing similar to that of the second embodiment is executed in steps S1 to S7, and after increasing the engine speed to the set speed in step S7, the process proceeds to step S30. In step S30, the jet sensor relief valve 15 is closed. As a result, as in the fourth embodiment, the hydraulic pressure of the closed circuit that circulates through the hydraulic pump 2 ′, the main relief valve 14, and the tank 11 increases, and the hydraulic oil temperature increases. In addition to the above, in the fifth embodiment, in step S31, the NC line communicating electromagnetic valve 45 is operated to make the pressures of both ports of the NC valve 40 the same pressure. This phenomenon is the same as the phenomenon when the discharge amount of the hydraulic pump 2 'decreases. Thereby, in step S32, a command is issued to the TVC-EPC valve 43 in order to increase the capacity of the hydraulic pump 2 '.

<Fake processing>
As described above, in the fifth embodiment, in order to increase the temperature of the hydraulic oil, the pressures of both ports of the NC valve 40 are forced to be the same to increase the capacity of the hydraulic pump 2 ′. That is, as described above, since the work implement load (hydraulic cylinder load) does not change when the work implement operation lever 5 is in the neutral state, the load on the hydraulic pump 2 ′ does not change. That is, the capacity of the hydraulic pump 2 ′ cannot be increased. Therefore, in the present embodiment, the pressures at both ports of the NC valve 40 are forcibly made the same to simulate the work machine load as if it increased. With this simulation, the capacity of the hydraulic pump 2 ′ can be increased even though the work machine operation lever 5 is in the neutral state. Therefore, not only the increase of the hydraulic pressure but also the discharge amount of the hydraulic pump 2 ′ can be increased, and the hydraulic oil can be warmed up efficiently in a short time.

The schematic block block diagram of the work vehicle which employ | adopted 1st Embodiment of this invention. The flowchart which shows the warming-up process of 1st Embodiment. The schematic block block diagram of the working vehicle which employ | adopted 2nd Embodiment of this invention. The flowchart which shows the warming-up process of 2nd Embodiment. The schematic block block diagram of the working vehicle which employ | adopted 3rd Embodiment of this invention. The flowchart which shows the warming-up process of 3rd Embodiment. The schematic block block diagram of the work vehicle which employ | adopted 4th Embodiment of this invention. The schematic block block diagram of the working vehicle which employ | adopted 5th Embodiment of this invention. The flowchart which shows the warming-up process of 5th Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2, 2 'Hydraulic pump 3 Hydraulic cylinder 5 Work implement operation lever 6 Lock lever 7 Automatic warm-up switch 15 Unload valve (jet sensor relief valve)
20 Controller 21 Engine speed sensor 22 Hydraulic oil temperature sensor 23 Pressure sensor 30 LS valve 31 PC valve 34 Solenoid valve for unloading 35 Solenoid valve for increasing load 45 Solenoid valve for NC line communication

Claims (7)

A warming-up device for warming up hydraulic fluid of a construction machine having a working machine driven by a hydraulic actuator,
Lock detecting means for detecting an on / off state of a lock mechanism for disabling the operation of the work implement;
Lever state detecting means for detecting the operation state of the operating lever of the work implement;
Hydraulic oil temperature detecting means for detecting the hydraulic oil temperature;
The lock detection means detects that the lock mechanism is in the on state, the operation lever state detection means detects that the operation lever is in the neutral state, and the hydraulic oil temperature detection means detects the first hydraulic oil temperature. When it is detected that the temperature is lower than the set temperature, the temperature raising means for raising the hydraulic oil temperature;
Warming-up device for construction machinery with   The warming-up device for a construction machine according to claim 1, further comprising an automatic warming-up switch capable of instructing from outside whether or not to execute a temperature raising process by the temperature raising means. A rotation speed detecting means for detecting the engine speed;
The temperature raising means performs a process of raising the hydraulic oil temperature after performing control for setting the engine speed to the predetermined speed when the speed detecting means is lower than the predetermined speed.
The warm-up device for a construction machine according to claim 1 or 2. The temperature raising means stops the temperature raising process when the hydraulic oil temperature exceeds a second set temperature higher than the first set temperature after executing the process for raising the hydraulic oil temperature.
The warm-up device for a construction machine according to any one of claims 1 to 3. The hydraulic actuator is supplied with operating hydraulic pressure by a hydraulic pump driven by an engine of a construction machine,
The temperature raising means increases the amount of oil discharged from the hydraulic pump to raise the temperature of the hydraulic oil,
The warming-up device for a construction machine according to any one of claims 1 to 4. The hydraulic actuator is supplied with operating hydraulic pressure by a hydraulic pump driven by an engine of a construction machine,
A closed circuit for returning the oil discharged from the hydraulic pump to the tank when the hydraulic actuator is not operated;
The temperature raising means raises the hydraulic pressure of the closed circuit to raise the temperature of the hydraulic oil,
The warming-up device for a construction machine according to any one of claims 1 to 4. The temperature raising means includes pseudo control means for forcibly generating a phenomenon similar to the phenomenon when the discharge amount of the hydraulic pump is reduced when the hydraulic actuator is not operated, and increases the hydraulic pressure of the closed circuit and Increase hydraulic oil discharge oil volume to raise hydraulic oil temperature,
The warming-up device for a construction machine according to claim 6.

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