JPH10274212A - Method and device for warming up of fluid circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform the efficient warring up operation of a hydraulic circuit. SOLUTION: An oil temperature sensor 21 to detect oil temperature is installed in a tank 17 of a hydraulic circuit, and the temperature sensor 21 is connected to a controller 23 through an oil temperature take-in line 22. Also the controller 23 is connected to a proportional solenoid valve 25 through a control line 24, and the proportional solenoid valve 25 is connected to a regulator 26 which variably controls the delivery flow rate of a hydraulic pump 12. In addition, when a control valve 13 is set at neutral, the controller 23 outputs the control signals according to the oil temperature detected by the oil temperature sensor 21 and controls the regulator 26 through the proportional solenoid valve 25. Then the regulator 26 increases the tilt angle of a swash plate 12a which controls the delivery flow rate of the hydraulic pump 12 larger as the oil temperature is lower so as to increase the delivery flow rate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for warming up a fluid circuit.

[0002]

2. Description of the Related Art FIG. 2 shows a conventional hydraulic circuit used in a construction machine such as a hydraulic shovel. In this circuit, a supply line 14 that supplies hydraulic oil from a variable discharge flow rate hydraulic pump 12 driven by an engine 11 to, for example, a control valve 13 of a closed center,
A supply line 16 that supplies hydraulic oil to a spool 15 for controlling various hydraulic actuators, and a bypass line 18 that directly discharges hydraulic oil to a tank 17 without passing through the supply line 16 are branched. Inside, a solenoid valve 19 that controls switching of discharge of hydraulic oil to the tank 17 by on / off operation is provided.

When the engine is started to perform a warm-up operation when the construction machine is operated, when the hydraulic pump 12 is automatically controlled to the minimum discharge flow rate, the solenoid valve 19 is operated.
Is switched on and the bypass line 18 is
The hydraulic oil supplied from the hydraulic pump 12 to the control valve 13 is supplied to each of the spools 15 in the neutral state, and is simultaneously discharged to the tank 17 via the solenoid valve 19.

In this way, by guiding the minimum flow rate of the pump into the control valve 13, a warm-up operation for warming components such as the hydraulic oil and the control valve 13 is performed.

When operating construction machinery, a solenoid valve
Turn off the bypass line 18 by turning off the 19
The supply line 16 to 15 is supplied with the entire pump discharge flow rate.

[0006]

In this conventional hydraulic circuit, the solenoid valve 19 is uniquely turned on and off regardless of the temperature of the hydraulic oil. Was required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to enable a warm-up operation of a fluid circuit to be performed efficiently.

[0008]

According to the first aspect of the present invention, when a control valve for controlling a hydraulic actuator is in a neutral state, a working fluid is supplied from a pump to the control valve to warm up a fluid circuit. In the warming-up method for driving, a warming-up method in a fluid circuit that detects the temperature of the working fluid and variably controls the discharge flow rate of the pump to increase as the temperature of the working fluid decreases.

[0010] By performing variable control so that the discharge flow rate of the pump increases as the temperature of the working fluid decreases, the warm-up operation of the fluid circuit is efficiently performed according to the temperature of the working fluid.

According to a second aspect of the present invention, there is provided a warming method for warming up a fluid circuit by supplying a working fluid from a pump to a control valve for controlling a fluid pressure actuator when the control valve for controlling the fluid pressure actuator is in a neutral state. A method for warming up a fluid circuit that detects the temperature of a working fluid and variably controls such that the lower the temperature of the working fluid, the greater the pressure loss of the working fluid discharged from the control valve to the tank.

The warm-up operation of the fluid circuit according to the temperature of the working fluid is performed by variably controlling the pressure loss of the working fluid discharged from the control valve to the tank as the temperature of the working fluid becomes lower. Is performed efficiently.

According to a third aspect of the present invention, there is provided a warming method for warming up a fluid circuit by supplying a working fluid from a pump to a control valve for controlling a fluid pressure actuator when the control valve for controlling the fluid pressure actuator is in a neutral state. Detects the temperature of the working fluid and performs variable control so that the lower the temperature of the working fluid, the greater the discharge flow rate of the pump and the greater the pressure loss of the working fluid discharged from the control valve to the tank. This is a method for warming up a fluid circuit.

When the temperature of the working fluid is lower,
By variably controlling the discharge flow rate of the pump to increase, and variably controlling the pressure loss of the working fluid discharged from the control valve to the tank to increase,
The warm-up efficiency of the fluid circuit is further improved according to the temperature of the working fluid.

According to a fourth aspect of the present invention, there is provided a warm-up device for warming up a fluid circuit by supplying a working fluid from a pump to the control valve when the control valve for controlling the fluid pressure actuator is in a neutral state. , A temperature sensor that detects the temperature of the working fluid, a controller that outputs a control signal corresponding to the temperature of the working fluid detected by the temperature sensor, and a variable control of the discharge flow rate of the pump according to the control signal output from the controller This is a warm-up device in a fluid circuit provided with a discharge flow rate control means.

Then, the temperature of the working fluid is detected by the temperature sensor, and a control signal corresponding to the temperature of the working fluid is output from the controller. Is variably controlled so that the discharge flow rate of the pump increases, and variably controlled so that the discharge flow rate of the pump decreases as the temperature of the working fluid increases.

According to a fifth aspect of the present invention, there is provided a warming-up device for warming up a fluid circuit by supplying a working fluid from a pump to the control valve when the control valve for controlling the fluid pressure actuator is in a neutral state. A temperature sensor that detects the temperature of the working fluid, a controller that outputs a control signal corresponding to the temperature of the working fluid detected by the temperature sensor, and a controller that is discharged from the control valve according to the control signal output from the controller to the tank. And a pressure loss control means for variably controlling the pressure loss of the working fluid.

Then, the temperature of the working fluid is detected by the temperature sensor, and a control signal corresponding to the temperature of the working fluid is output from the controller. When the temperature of the working fluid is low, Is variably controlled so that the pressure loss of the working fluid discharged to the tank increases, and variably controlled so that the pressure loss of the working fluid discharged to the tank decreases as the temperature of the working fluid increases.

According to a sixth aspect of the present invention, there is provided a warming-up device for warming up a fluid circuit by supplying a working fluid from a pump to the control valve when the control valve for controlling the fluid pressure actuator is in a neutral state. , A temperature sensor that detects the temperature of the working fluid, a controller that outputs a control signal corresponding to the temperature of the working fluid detected by the temperature sensor, and a variable control of the discharge flow rate of the pump according to the control signal output from the controller And a pressure loss control means for variably controlling a pressure loss of a working fluid discharged from a control valve to a tank in response to a control signal output from a controller. .

Then, the temperature of the working fluid is detected by the temperature sensor, a control signal corresponding to the temperature of the working fluid is output from the controller, and when the temperature of the working fluid is low by the discharge flow control means receiving the control signal. Is variably controlled so that the discharge flow rate of the pump increases, and variably controlled so that the discharge flow rate of the pump decreases as the temperature of the working fluid increases. At the same time, the pressure loss control means receiving the control signal variably controls the pressure loss of the working fluid discharged to the tank when the temperature of the working fluid is low so as to increase the pressure loss. Variably controlled so as to reduce the pressure loss of the working fluid discharged to the drain.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. The same parts as those in the conventional example shown in FIG.

A supply line 14 for supplying a working fluid as a working fluid from a variable discharge flow type hydraulic pump 12 driven by an engine 11 to, for example, a closed center control valve 13 is provided with a hydraulic line as various fluid pressure actuators. Actuator (hydraulic cylinder, hydraulic motor, etc.)
A supply line 16 for supplying hydraulic oil to a spool 15 for controlling the pressure and a bypass line 18 for directly discharging hydraulic oil to a tank 17 without passing through the supply line 16.

The tank 17 is provided with a temperature sensor (hereinafter, referred to as an oil temperature sensor 21) for detecting the temperature of the hydraulic oil (hereinafter, referred to as an oil temperature). The oil temperature sensor 21
It may be installed in a pipeline such as the supply line 14, 16 or the bypass line 18.

The oil temperature sensor 21 is connected to a controller 23 of an electronic control circuit via an oil temperature intake line 22. The controller 23 is connected to a hydraulic pump via a control line 24 and a proportional solenoid valve 25 as an electro-oil converter. 12 is connected to a regulator 26 as a discharge flow control means for variably controlling the discharge flow.

When all the spools 15 of the control valve 13 are in the neutral state, the controller 23 outputs a control signal in accordance with the oil temperature detected by the oil temperature sensor 21 and outputs a control signal to the proportional solenoid valve.
25 outputs a control pressure by a proportional operation according to the control signal output from the controller 23,
Adjusts the tilt angle of the swash plate 12a, which controls the discharge flow rate of the hydraulic pump 12, according to the control pressure output from the proportional solenoid valve 25.

Further, a bypass valve 27 is provided in the bypass line 18 as pressure loss control means for variably controlling the pressure loss of the hydraulic oil discharged from the control valve 13 to the tank 17.

The bypass valve 27 receives a control signal (current) output from the controller 23 to a control line 28 in accordance with the oil temperature detected by the oil temperature sensor 21 when all the spools of the control valve 13 are in a neutral state. This is a proportional solenoid valve that controls the spool opening by a proportional operation according to the control signal to adjust the pressure loss in the bypass line 18.

Next, the operation of the embodiment shown in FIG. 1 will be described.

When the engine 11 is started, since not only the engine 11 but also the oil temperature and the temperature of the hydraulic equipment are low, the next warming is performed on condition that all the spools 15 in the control valve 13 are in the neutral state. Machine operation.

The controller 23 transmits the oil temperature information of the tank 17 and the like detected by the oil temperature sensor 21 to the oil temperature intake line 22.
The control signal corresponding to the oil temperature is output to the control line 24. The regulator 26 controls the tilt angle of the swash plate 12a of the hydraulic pump 12 via the proportional solenoid valve 25 receiving the control signal, and variably controls the pump discharge flow rate.

For example, the tilt angle of the swash plate 12a is controlled so that the discharge flow rate of the hydraulic pump 12 increases as the oil temperature decreases.
The tilt angle of the swash plate 12a is controlled to return so that the discharge flow rate of the hydraulic pump 12 decreases to a minimum value as the oil temperature increases.

Similarly, the controller 23 includes an oil temperature sensor 21
And outputs a control signal to the control line 28 in accordance with the oil temperature. Upon receiving this control signal, the bypass valve 27 adjusts the pressure loss of the hydraulic oil directly discharged to the tank 17 via the bypass line 18.

For example, when the oil temperature is lower, the control valve
The opening degree of the bypass valve 27 is throttle-controlled so that the pressure loss of the hydraulic oil discharged from the tank 13 to the tank 17 increases, and the pressure loss of the hydraulic oil discharged to the tank 17 decreases as the oil temperature increases. Thus, the opening of the bypass valve 27 is variably controlled in the enlargement direction.

By controlling the discharge flow rate by the regulator 26 or the pressure loss control by the bypass valve 27, the lower the oil temperature at the time of starting the warm-up operation of the construction machine, the faster the temperature of the hydraulic oil due to the warm-up operation. As a result, the warm-up operation of the hydraulic circuit can be efficiently performed, the warm-up operation can be completed in a short time, and construction machine work can be started.

The discharge flow rate control by the regulator 26 can be applied to both a closed center circuit using a closed center control valve 13 and an open center circuit using an open center control valve.

On the other hand, the pressure loss control by the bypass valve 27 is more suitable when performing the warm-up operation of the closed center circuit than the open center circuit.

Therefore, in the closed center circuit, both the discharge flow rate control and the pressure loss control may be performed simultaneously as required, or any one of the controls may be performed separately.

At this time, if only the discharge flow rate control by the regulator 26 is selected, the bypass valve 27 does not need to operate proportionally, and the bypass valve 27 is fully opened or the conventional solenoid valve 19 (FIG. 2) It is better to use

On the other hand, when only the pressure loss control by the bypass valve 27 is selected, the swash plate 12a may be fixed at a fixed tilt angle.

Although the present invention is suitable for warm-up operation of a hydraulic circuit such as a construction machine, the present invention can be applied to a hydraulic circuit other than a hydraulic circuit and, if necessary, to a pneumatic circuit. Applicable.

[0040]

According to the first aspect of the present invention, the variable control is performed such that the lower the temperature of the working fluid is, the larger the discharge flow rate of the pump is. Therefore, even when the temperature of the working fluid is low, the fluid circuit is warmed up. The operation can be performed efficiently, and the time required for warming up the fluid circuit can be reduced by improving the warming-up efficiency even in a cold region or the like.

According to the second aspect of the invention, the variable control is performed such that the lower the temperature of the working fluid is, the larger the pressure loss of the working fluid discharged from the control valve to the tank is. Also, the warming-up operation of the fluid circuit can be performed efficiently, and the time required for warming up the fluid circuit can be shortened by improving the warming-up efficiency even in a cold region.

According to the third aspect of the present invention, the variable control is performed so that the lower the temperature of the working fluid is, the larger the discharge flow rate of the pump is, and the pressure loss of the working fluid discharged from the control valve to the tank is reduced. Since the variable control is performed so as to increase, the warm-up efficiency of the fluid circuit can be further improved synergistically by the discharge flow rate control and the pressure loss control according to the temperature of the working fluid.

According to the present invention, the discharge flow rate control means is controlled by a control signal corresponding to the temperature of the working fluid, which is detected by the temperature sensor and outputted from the controller,
Since the discharge flow rate of the pump is variably controlled, the warm-up operation of the fluid circuit can be efficiently performed according to the temperature of the working fluid, the warm-up efficiency at low temperatures can be improved, and the time required for warming up the fluid circuit can be reduced. Can be shortened. Further, the present invention is applicable to both closed center circuits and open center circuits.

According to the fifth aspect of the present invention, the pressure loss control means is controlled by a control signal corresponding to the temperature of the working fluid, which is detected by the temperature sensor and output from the controller,
Since the pressure loss of the working fluid discharged from the control valve to the tank is variably controlled, the warm-up operation of the closed center circuit can be efficiently performed according to the temperature of the working fluid, and the time required for warm-up can be reduced.

According to the present invention, the discharge flow rate control means is controlled by a control signal corresponding to the temperature of the working fluid, which is detected by the temperature sensor and output from the controller,
Since the discharge flow rate of the pump is variably controlled and the pressure loss control means is controlled by the control signal to variably control the pressure loss of the working fluid discharged to the tank, the warming of the fluid circuit according to the temperature of the working fluid is controlled. The machine operation can be synergistically and efficiently performed by the discharge flow rate control and the pressure loss control, and the warm-up efficiency at low temperatures can be remarkably improved.

[Brief description of the drawings]

FIG. 1 is a fluid circuit diagram showing an embodiment of a warm-up device in a fluid circuit according to the present invention.

FIG. 2 is a fluid circuit diagram showing a warm-up device in a conventional fluid circuit.

[Explanation of symbols]

 12 Pump 13 Control valve 17 Tank 21 Temperature sensor (oil temperature sensor) 23 Controller 26 Regulator as discharge flow control means 27 Bypass valve as pressure loss control means

Claims (6)

[Claims] 1. A warm-up method for warming up a fluid circuit by supplying a working fluid from a pump to a control valve when a control valve for controlling a fluid pressure actuator is in a neutral state, wherein a temperature of the working fluid is detected. A warm-up method in a fluid circuit, wherein variable control is performed such that the lower the temperature of the working fluid, the higher the discharge flow rate of the pump. 2. A method for warming up a fluid circuit by supplying a working fluid from a pump to a control valve when a control valve for controlling a fluid pressure actuator is in a neutral state, wherein a temperature of the working fluid is detected. A warm-up method in a fluid circuit, wherein variable control is performed so that the pressure loss of the working fluid discharged from the control valve to the tank increases as the temperature of the working fluid decreases. 3. A warm-up method for warming up a fluid circuit by supplying a working fluid from a pump to a control valve when a control valve for controlling a fluid pressure actuator is in a neutral state, wherein a temperature of the working fluid is detected. A fluid circuit characterized by variable control such that the lower the temperature of the working fluid is, the larger the discharge flow rate of the pump is, and variable control is performed such that the pressure loss of the working fluid discharged from the control valve to the tank is increased. How to warm up. 4. A warm-up device for warming up a fluid circuit by supplying a working fluid from a pump to the control valve when a control valve for controlling a fluid pressure actuator is in a neutral state, wherein a temperature of the working fluid is detected. A temperature sensor, a controller that outputs a control signal corresponding to the temperature of the working fluid detected by the temperature sensor, and a discharge flow rate control unit that variably controls a discharge flow rate of the pump in accordance with the control signal output from the controller. A warm-up device for a fluid circuit, comprising: 5. A warm-up device for warming up a fluid circuit by supplying a working fluid from a pump to the control valve when a control valve for controlling a fluid pressure actuator is in a neutral state, wherein a temperature of the working fluid is detected. A temperature sensor, a controller that outputs a control signal corresponding to the temperature of the working fluid detected by the temperature sensor, and a variable pressure loss of the working fluid discharged from the control valve to the tank according to the control signal output from the controller. A warm-up device in a fluid circuit, comprising: a pressure-loss control means for controlling the pressure loss. 6. A warm-up device for warming up a fluid circuit by supplying a working fluid from a pump to a control valve for controlling a fluid pressure actuator when the control valve for controlling the fluid pressure actuator is in a neutral state detects a temperature of the working fluid. A temperature sensor, a controller that outputs a control signal according to the temperature of the working fluid detected by the temperature sensor, a discharge flow control unit that variably controls a discharge flow rate of the pump according to a control signal output from the controller, and a controller A pressure loss control means for variably controlling the pressure loss of the working fluid discharged from the control valve to the tank in accordance with the control signal output from the control circuit.