JPS6367413A - Warming up process for construction machine - Google Patents

Abstract

PURPOSE:To perform warming-up just enough and surely by making continuous and automatic worming-up of both engine and hydraulic working oil with operation of a warming-up start switch. CONSTITUTION:An engine warming-up termination signal causes a concellation of low speed revolution signal sent from a controller 24 to an engine speed control device 6. The oil discharged from a pump is relieved through a relief circuit with the operation of a relief valve control means 16 controlled by the controller 24. Further, the quantity of oil discharged from the pump is increased with the control of a regulator drive means 19, and the worming-up of the working oil is performed in this state. Then a working oil warming-up termination signal stops the relief of the oil discharged from the pump according to a working oil warming-up end signal. This arrangement makes sure of the warming-up operation.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is a construction machine such as a hydraulic excavator or a crane, which automatically pumps up the hydraulic oil in the engine and hydraulic system when starting, especially in cold weather. ” for h > 1.

(Prior Art) Conventionally, regarding the warming-up of 11 construction machinery, only a method has been proposed in which the hydraulic fluid of the hydraulic system is targeted for A-tank-up, as shown in Special Publication No. 171111f (No. 59-54805). The warming-up of the engine, which is the drive source for the hydraulic system, is carried out mainly by operating the operating stone mill.

For this reason, the pump starts to warm up the hydraulic oil by running the pump at full capacity before the engine has warmed up sufficiently, which may cause the engine load to become excessive and cause the engine to stall, or warm up the engine to be unnecessary. The warm-up of the entire machine is uncertain and inefficient, as the warm-up of the hydraulic oil is delayed.

(Object of the Invention) Therefore, the present invention provides a method for warming up a construction machine, which can continuously, automatically and reliably warm up an engine and hydraulic oil.

(Structure of the Invention) The present invention is characterized by an engine, a q'gl displacement hydraulic pump driven by the engine, an actuate driven by oil discharged from the pump,
A control valve that controls the operation of the actuator, an engine speed setting device that sets the engine speed, a regulator that controls the amount of oil discharged from the pump, and a regulator drive device that drives the regulator. In a construction machine equipped with a relief valve and a relief circuit that returns pump discharge oil to a tank by the operation of the relief valve, a warming-up start switch that commands the start of warming-up and an engine warming-up end signal are generated. an engine warm-up end signal generation means for generating a hydraulic oil warm-up end signal; a hydraulic oil warm-up end signal generating means for generating a hydraulic oil warm-up end signal; The input controller and
Engine speed control means for driving the engine speed setting means to command a set rotation speed, and relief valve control means for controlling the upper leaf valve to zero.1. Warming-up start command (Based on No. 9, the controller outputs a low-speed rotation signal to the engine speed υ control means to control the engine speed to a low speed suitable for engine warming-up. At the same time, the controller outputs an oil amount reduction signal to the regulator driving means to drive the regulator so that the pump discharge oil becomes almost the minimum, and after warming up the engine in this state, the engine warming up ends. Based on the signal, canceling the low speed rotation signal from the controller [1-ra to the engine rotation speed control means;
and outputting a relief valve activation signal from the controller to the relief valve control means to operate the relief valve, thereby relieving the pump discharge oil through the relief circuit, and controlling the regulator drive means to control the discharge oil section of the pump. After warming up the hydraulic oil in this state, the controller releases the relief valve operation signal to the relief valve control means based on the hydraulic oil warming-up completion signal,
The present invention provides a warming-up method for construction machinery that avoids stopping the relief of pump discharge oil by the relief circuit.

(Example) In the figure, 1 is an engine, 2 is a hydraulic pump (hereinafter referred to as the main pump) driven by the engine 1, 3 is the pilot pump, and 4 is driven by pressure oil from the main pump 2. A hydraulic cylinder 5 is an electromagnetic control valve that controls the operation of the hydraulic cylinder 4. Reference numeral 6 denotes a governor lever as an engine rotation speed setting means for adjusting the fuel injection ω of the engine 1 to set the engine rotation speed, and 7 is an engine rotation speed control means for driving the governor lever 6.

This engine speed control means 7 includes a control lever 8 for operating the governor lever 6, and a drive cylinder 10 for rotationally driving the control lever 8 via a link 9.
and a first electromagnetic switching valve 11 that controls the operation of the drive cylinder 10. The link 9 is on the right side of the elongated hole 9a,
A pin 8a provided on the control lever 8 is engaged with this elongated hole 9a. During normal operation, the bottle 8a is located in the middle of the long hole 9a, and is in a hanging state as it moves freely within the long hole 9a. A throttle lever (not shown) is connected to the control lever 8, and in normal operation, the control lever 8 is driven by the driver's operation of the throttle lever, which operates the governor lever 6. The engine speed is arbitrarily set within the entire range from maximum to minimum. On the other hand, engine 1
When warming up, the drive cylinder 10 is extended (this point will be explained in detail later), and the link 9 moves downward in the figure! II L, bottle 8a is long hole 9a
Press the control lever 8 downward in the figure while touching the upper end of the figure. As a result, the governor lever 6 is set to the warming-up position, and the rotational speed of the engine 1 is set to a low rotational speed suitable for warming-up (for example, 1200 ppm).

(hereinafter referred to as the warming-up rotation speed). The first electromagnetic switching valve 11 is provided between the pilot pump 3 and the drive cylinder 10, and when the oil discharged from the pilot pump 3 is supplied to the drive cylinder 10 via this switching valve 11, the cylinder 10 is extended. Operate.

The control valve 5 is set to the upper or lower position in the figure when the hydraulic cylinder 4 is driven, and at this time, pressure oil from the main pump 2 is passed through the check valve 12, 13 and the control valve 5 to the push side or the lower side of the hydraulic cylinder 4. Supplied to the pull side. In addition, the control valve 5 is connected to the bypass passage 5a which is open in the neutral position, and during normal operation 5A, when this control 1 call valve is in the neutral state, the pressure oil from the main pump 2 is transferred to the bypass passage 5a and the pilot switch. It is returned to the tank via a valve 14 and a low pressure relief unload valve (so-called negative control valve) 15.

16 is a second electric (iI, I) switching valve, and when this switching valve 16 is set to position d on the lower side of the figure, the pilot pump 3
The hydraulic pressure is applied as pilot pressure to the pilot switching valve 14 and the low pressure relief unloading valve 15 through the switching valve 16, and this causes the pilot switching valve 14 to open m and the low pressure relief unloading valve 15 to open. Become. When the pilot ψJ switching valve 14 becomes idle, the control valve 5
The oil return flow path passing through the neutral bypass passage 5a is blocked, and instead a relief circuit is formed that passes from the check valve 12 to the relief valve 17 and the low pressure relief unload valve 15, and the pressure oil from the main pump 2 is It is returned to the tank through a relief circuit. That is, t5, second electromagnetic switching valve 1
6 and the pilot switching valve 14, the relief valve 17
A relief valve tI111111 means for controlling the operation OJ is constructed.

Reference numeral 18 denotes a regulator that controls the discharge oil piece of the main pump 2, and this regulator 18 receives negative control pressure (inlet pressure of the facing valve 15) from the low pressure relief unload valve 15.
and the secondary pressure of the electromagnetic proportional pressure reducing valve 19 are applied, and the total pressure drives the 1" regulator 18 to control the oil lift at the port t111 of the main pump 2.
The amount of oil discharged from the pump is controlled so that the larger the total pressure is, the smaller the amount is, and the smaller the total pressure is, the larger the amount is.

Further, 20 is a warming-up start switch that commands the start of warming-up, 21 is an engine rotation speed detection sensor, 22 is a governor stroke detection sensor, and 23 is an oil temperature detection sensor. A signal from the controller 24 is inputted from the controller 24 to the first electromagnetic switching valve 11,
An operation signal is output to each electromagnetic operation section of the second electromagnetic switching valve 16 and the electromagnetic proportional pressure reducing valve 19. Also, this controller 2
4 has a built-in timer (not shown) that starts timing operation when the warm-up start switch 20 is turned on (48), and the warm-up time for the engine 1 is set by this timer.

Next, a warming-up method based on the above configuration will be explained.

(I) Warming-up of the engine 1 After the engine starts, the driver turns on the warming-up start switch 20, and this switch-on signal is sent to the controller 24 as a warming-up start IH command signal.
is input, and warming up of the engine 1 is started.

First, the control fi signal a is output from the controller 24 to the first electromagnetic switching valve 11, and the switching valve 11 is switched to the lower position in the figure. As a result, pressure oil from the pilot pump 3 is supplied to the drive cylinder 10 of the engine speed control means 7 via the first electromagnetic switching valve 11, and the cylinder 10 is extended. Therefore, as described above, by pushing the control lever 8 downward in the figure through the link 9, the rotational speed of the engine 1 is set to the warming-up rotational speed, and the engine 1 is warmed up in this state.

On the other hand, at the same time as warming-up starts, an operation signal is output from the controller 24 to the electromagnetic proportional pressure reducing valve 19, which opens the proportional pressure reducing valve 19, and the discharge pressure of the pilot pump 3 is reduced by the pressure reducing valve 19. It is applied to the regulator 18 as an oil amount decrease signal. This regulator 18 also includes a low pressure relief unload switching valve 15.
The negative control pressure is also applied as an oil amount reduction signal, and the amount of oil discharged from the main pump 2 is approximately minimized by the regulators i, II and III based on this negative control pressure and the secondary pressure of the pressure reducing valve 19.

In this way, while the engine 1 is warming up, the oil discharged from the main pump 2 becomes almost the minimum and the engine load is kept at the minimum, so even if the control lever 5 is operated during the engine warming up, There is no risk of engine stalling.

During this engine warming-up, the oil discharged from the main pump 2 is returned to the tank through the neutral bypass passage 5a of the control valve 5, the pilot switching valve 14, and the low pressure relief unload valve 15.

Warming-up of the engine 1 is carried out within a time set by a timer in the controller 24, and after the set time is over, the warm-up of the hydraulic fluid continues automatically.

(U) Warming up of hydraulic oil At the same time as the above-mentioned timer setting time ends, the operation signal a from the controller 24 to the first electromagnetic switching valve 11 is released. As a result, the drive cylinder 10 of the engine speed control means returns to the contracted state, so that the engine speed becomes the speed commanded by the throttle lever.

Further, the controller 24 outputs an operation signal C to the second electromagnetic switching valve 16, thereby switching the switching valve 16 to the lower position in the figure. When this happens, the hydraulic pressure from the pilot pump 3 is applied as pilot pressure to the pilot switching valve 14 and the low pressure relief unload valve 15 via the switching valve 16, and the pilot switching valve 14 switches to the closed position shown in the lower side of the figure. Low pressure relief unload valve 15 is held open. In this way, the oil return path from the neutral bypass passage 5a of the control valve 5 through the pilot switching valve 14 is blocked, so that the circuit pressure is reduced to one level and the relief valve 17 is activated. As a result, the oil discharged from the main pump 2 is relieved through the relief circuit including the check valve 12, the relief valve 17, and the low pressure relief fan load valve 15, and power loss (heat generation) is caused by this relief action.
The hydraulic oil is warmed up by this.

At this time, the negative control pressure caused by the low pressure relief unload 15 becomes zero. On the other hand, the electromagnetic proportional pressure reducing valve 19 remains open due to the operation signal from the controller 24.

Therefore, only the secondary pressure of the pressure reducing valve 19 acts on the regulator 18, and as a result, an oil amount increase signal is input to the regulator 18, so that the oil content discharged from the main pump 2 increases η. However, in this case, the signals from the engine rotation speed detection sensor 21 and the governor stroke detection sensor 22 are input to the controller 24, and the current engine load is calculated by the controller 24 based on the current engine rotation speed and the governor stroke. An operation signal having a magnitude corresponding to the magnitude of the engine load is output from the controller 24 to the electromagnetic proportional pressure reducing valve 19. As a result, the secondary pressure of the pressure reducing valve 19 is adjusted to a value corresponding to the engine load and acts on the regulator 18, so that the discharge oil m of the main pump 2 is controlled to increase within a range that does not cause engine stall. Ru. In this way, the pump discharge oil is relieved by the relief circuit, so that the hydraulic oil is efficiently pumped.

Then, when the temperature of the hydraulic oil rises to a predetermined temperature as a result of this warming-up, the oil temperature detection sensor 23 detects this and sends a hydraulic oil warming-up completion signal to the controller 24. In response to this end signal, the operation signal from the controller 24 to the second electromagnetic switching valve 16 is released, so the relief action by the relief valve 17 is stopped.

With the above, the continuous warming-up of the engine 163 and the hydraulic oil is completed. After this, in order to save energy, the operation signal a is again inputted from the controller 24 to the first electromagnetic switching valve 11, and the switching valve 1 is
1 switches and operates, and the engine speed fi, II II
The XI means 7 automatically sets the engine speed to the warming-up speed. Further, at the same time as the warming-up ends, a display means such as a lamp or a buzzer (not shown) is activated to indicate to the driver that the warming-up has ended.

Then, the driver presses the warm-up start switch 20.
When the engine is turned off, the first switching valve 11 is switched to the upper position in the figure, the engine speed is set to the speed commanded by the throttle lever, and full-scale operation is possible from then on.

By the way, in the above embodiment, the warm-up time of the engine 1 is set by a timer, but for example, the radiator water temperature of the engine 1 is detected by a temperature sensor, and the completion of warming-up of the engine 1 is determined by 7+1 based on this water temperature. II may be used. Further, as the engine rotation speed control means, in the above embodiment, the drive cylinder (hydraulic cylinder) 10 is configured to be controlled by the first electromagnetic switching valve 11.
0 may be replaced with an electromagnet, and the engine speed may be controlled by directly controlling the electromagnet a and II with a controller. Furthermore, as a regulator driving means,
In the above embodiment, the electromagnetic proportional pressure reducing valve 19 and the low pressure relief unload valve 15 are used in combination, but it is also possible to have a configuration in which the regulator 18 is driven only by the pressure reducing valve 19.

(Effects of the Invention!!) As described above, according to the present invention, the warm-up of the engine and hydraulic fluid can be automatically and continuously performed by operating the warm-up start switch. It is possible to increase the engine reliably and efficiently without over-returning.Also, during warm-up of the engine, the pump discharge oil level is kept to a minimum to keep the engine load small. It is possible to reliably prevent the engine from stalling.

[Brief explanation of drawings]

The figure shows an example of the configuration of electric and hydraulic circuits for implementing the present optical method. DESCRIPTION OF SYMBOLS 1... Engine, 2... Pump, 4... Hydraulic cylinder as actuator, 5... Control valve, 6... Governor lever as engine rotation a setting means, 7... Engine rotation speed control Means, 8... Control lever constituting the f-stage, 9... The same link, 10... The same drive cylinder, 11... The same electromagnetic switching valve, 17... The relief valve, 16... Electromagnetic switching valve constituting the relief valve control means, 14...times pilot switching valve, 18...regulator, 19...'rf1 magnetic proportional pressure reducing valve constituting the regulator driving means, 15...
・The same low pressure relief unload valve, 20...Warming-up start switch, 23...Oil temperature sensor as means for generating a hydraulic oil A-warming-up end signal, 24...
·controller. Patent Applicant Kobe Steel Co., Ltd. Representative Patent Attorney Etsushi Kotani Patent Attorney 1 Chief 1) Masamukai Patent Attorney Yasuo Itaya (Written Procedural Amendments Voluntary) October 23, 1986, , , , , , j,

Claims (1)

[Claims] 1. An engine, a variable displacement hydraulic pump driven by this engine, an actuator driven by oil discharged from this pump, a control valve that controls the operation of this actuator, and an engine rotation that sets the rotation speed of the engine. a regulator for controlling the amount of oil discharged from the pump; a regulator drive means for driving the regulator; and a relief circuit having a relief valve and returning the oil discharged from the pump to the tank by the operation of the relief valve. In the construction machine, a warm-up start switch for commanding the start of warm-up, an engine warm-up end signal generating means for generating an engine warm-up end signal, a hydraulic oil warm-up end signal generating means for generating a hydraulic oil warm-up end signal, and the above-mentioned a controller to which a warm-up start command signal, an engine warm-up end signal, and a hydraulic oil warm-up end signal are input; an engine speed control means for driving the engine speed setting means to command a set speed;
relief valve control means for controlling the operation of the relief valve, and based on the warm-up start command signal, the controller outputs a low-speed rotation signal to the engine rotation speed control means to adjust the engine rotation speed to warm up the engine. At the same time as controlling the engine speed to an appropriate low speed, the controller outputs an oil volume reduction signal to the regulator drive means to drive the regulator so that the pump discharge oil is almost at its minimum, and in this state the engine is warmed up. After that, based on the engine warm-up end signal, the low speed rotation signal from the controller to the engine speed control means is canceled, and the controller outputs a relief valve activation signal to the relief valve control means to operate the relief valve. As a result, the pump discharge oil is relieved by the relief circuit, and the amount of pump discharge oil is increased by controlling the regulator driving means, and after warming up the hydraulic oil in this state, the hydraulic oil warm-up end signal is activated. A warming-up method for construction machinery, comprising: canceling a relief valve activation signal from a controller to the relief valve control means to stop relief of pump discharge oil by the relief circuit.