JP2012007439A - Hydraulic fluid preheating mechanism and preheating method of construction machinery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To preheat hydraulic fluid without an external electric power source and without the loss of fuel.SOLUTION: A hydraulic excavator includes an engine 9 and a hydraulic fluid tank 19 supplying hydraulic pumps 13 and 14 with hydraulic fluid. And in the hydraulic fluid tank 19, there are provided a heater 20 for heating the hydraulic fluid in the hydraulic fluid tank 19 and a temperature sensor 21 for measuring the temperature of the hydraulic fluid. In a direct current circuit 11 for supplying electric power from an electrical storage device 10 to the heater 20, there is provided a changeover switch 23 for switching between continuity and cutoff. There is provided a control means 25 for turning the changeover switch 23 on the side of continuity when the hydraulic fluid temperature measured by the temperature sensor 21 is lower than a predetermined temperature. In the electrical storage device 10, there is provided an operation switch 22 for continuity without the start-up of the engine.

Description

  The present invention drives a hydraulic pump with electric power supplied from a power storage device and supplies hydraulic oil in a hydraulic oil tank to operate an actuator, or an electric actuator with electric power supplied from a power storage device. The present invention relates to a working oil preheating mechanism and a preheating method for a construction machine that preheats working oil in a working oil tank at the time of start-up or the like in a construction machine to be operated.

In a construction machine, for example, a hydraulic excavator, an upper swing body is provided on an upper portion of a lower traveling body so that the upper swing body can swing, and an operating machine is provided on the upper swing body so as to be movable up and down. Hydraulic oil for driving an actuator such as a boom or a stick in the work machine is stored in a hydraulic oil tank, and is circulated by a hydraulic pump to drive the actuator.
On the other hand, in recent years, hybrid hydraulic excavators and the like equipped with a large-capacity, high-output power storage device have been proposed and commercialized from the viewpoint of reducing fuel consumption.
By the way, when starting a hydraulic excavator equipped with a hydraulically driven actuator in cold or extremely cold regions, the viscosity of the hydraulic fluid increases when the temperature of the hydraulic oil is low, causing cavitation in each actuator and causing equipment damage or hydraulic control. There is a drawback that the operation delay of the valve is caused. Therefore, in cold districts and the like, the hydraulic oil is warmed by starting the engine of the hydraulic excavator and driving the hydraulic pump to drive the working machine in the air.

For example, in the construction machine described in Patent Document 1, the water supply pump is driven simultaneously with the start of the engine in a cold region or the like to circulate water in a pipe that forms a closed circuit. Then, heat is exchanged by the engine to make the water in the piping warm and circulate in the hydraulic oil tank, and heat is exchanged with the hydraulic oil in the hydraulic oil tank to preheat the hydraulic oil.
Alternatively, the working oil is warmed by starting the engine of the construction machine and driving the pump. When the pump is driven, the pump is relieved or the working machine is wastefully operated in the air.

However, the former requires a water pump, piping, heat exchanger, and the like in addition to the engine, and the configuration is complicated and expensive. In addition, it cannot be applied to a construction machine that does not include these. In the latter case, relieving the pump or repeating the aerial operation of the work machine requires work time and requires the operator to operate the operation lever, so care must be taken. Moreover, in any case, the hydraulic oil must be preheated while the engine is started, and there is a disadvantage that fuel is consumed wastefully.
Further, when the pump is relieved, if one part of the spool is fixed by, for example, stick-out and the pump relief is continued, only one part in the control valve becomes hot. For this reason, a temperature difference is generated in the control valve, which causes distortion in the interior, and there is a possibility that the thermal shock occurs and the spool is fixed.

  As means for improving such a problem, a hydraulic oil preheating device described in Patent Document 2 has been proposed. In the hydraulic excavator according to the present invention, a heater for preheating the hydraulic oil in the hydraulic oil tank is attached to the outer wall of the hydraulic oil tank. In cold weather, an external power supply is connected to the heater with a connection cable, and power is supplied from the external power supply to the heater to preheat the hydraulic oil in the hydraulic oil tank.

JP 58-195637 A Japanese Patent Laid-Open No. 10-331205

  However, in the hydraulic excavator described in Patent Document 2, an external power supply and a connection cable must always be prepared when starting the engine in a cold region or a very cold region. At the time of starting, it is troublesome to install an external power source and connect the connection cable to the heater of the hydraulic oil tank.

  In view of such circumstances, the present invention eliminates the need to use an external power source or the like, and allows the hydraulic oil to be preheated without causing fuel loss due to engine starting, and a hydraulic oil preheating mechanism and preheating method for a construction machine. The purpose is to provide.

The hydraulic oil preheating mechanism for a construction machine according to the present invention is a construction machine including an engine and a hydraulic oil tank that supplies hydraulic oil to a hydraulic pump. And a preheating means for heating the hydraulic oil, and supplying the electric power from the power storage device to the preheating means to heat the hydraulic oil in the working tank.
According to the preheating mechanism of the construction machine according to the present invention, when the hydraulic oil in the hydraulic oil tank supplied to the hydraulic pump is cold in a cold region or the like, at the time of starting, for example, at the stage before starting the engine with the operating key turned ON, By supplying electric power from the power storage device to the preheating means and heating the hydraulic oil in the hydraulic tank, the hydraulic oil can be warmed, and convection of the hydraulic oil heated in the hydraulic oil tank occurs and the hydraulic oil temperature is increased. It is evenly adjusted and warmed. Therefore, it is possible to prevent a part of the control valve to which the hydraulic oil is supplied from becoming hot and distorting and causing a thermal shock. In addition, since the hydraulic oil can be heated by supplying power from the power storage device before the engine is started, fuel consumption can be suppressed, and there is no need to connect an external power source when the hydraulic oil is heated.

The hydraulic oil preheating mechanism for a construction machine according to the present invention includes a temperature measuring unit that measures the temperature of the hydraulic oil in the hydraulic oil tank, and a power storage device when the temperature of the hydraulic oil measured by the temperature measuring unit is lower than a set temperature. It is preferable to further comprise control means for supplying power to the preheating means.
When heating the hydraulic oil, the temperature of the hydraulic oil in the hydraulic oil tank is measured by the temperature measuring means, and when the control means determines that the hydraulic oil temperature is lower than the set temperature, power is supplied from the power storage device to the preheating means. When the temperature of the hydraulic oil reaches the set temperature, the supply of power from the power storage device is cut off.

Further, the hydraulic oil preheating mechanism for a construction machine according to the present invention is provided with an electric wiring for supplying electric power from the power storage device to the preheating means, and a changeover switch capable of switching between conduction and interruption of the electric wiring, and the control means is It is preferable that the changeover switch is turned on when the temperature of the hydraulic oil measured by the temperature measuring means before starting the engine is lower than the set temperature, and the changeover switch is shut off when the temperature of the hydraulic oil exceeds the set temperature. .
By switching conduction and interruption of the changeover switch by the control means, it is possible to control the supply and interruption of power from the power storage device to the preheating means.

The hydraulic oil preheating method for a construction machine according to the present invention includes a step of operating a power storage device installed as a power source of a driving system before starting an engine, and a step of operating hydraulic oil in a hydraulic oil tank for supplying hydraulic oil to a hydraulic pump. A step of measuring the temperature, and a step of heating the hydraulic oil by supplying power from the power storage device to a preheating means for heating the hydraulic oil in the hydraulic oil tank when it is detected that the temperature of the hydraulic oil is lower than the set temperature. It is provided with.
According to the present invention, before starting an engine that consumes fuel, a power storage device installed as a power source for a drive system in a construction machine is used to store power in the power storage device when the hydraulic oil in the hydraulic oil tank is lower than a set temperature. The supplied electric power can be supplied to the preheating means to heat the hydraulic oil in the hydraulic oil tank. Therefore, the hydraulic oil can be preheated without using an external power source, starting the engine, starting the hydraulic pump to relieve, or performing the aerial operation of the work machine by starting the hydraulic pump.

According to the hydraulic oil preheating mechanism and the preheating method for the construction machine according to the present invention, the hydraulic oil in the hydraulic oil tank is warmed without starting the engine by supplying electric power from the power storage device to the preheating means of the hydraulic oil tank. Can reduce fuel consumption. In addition, since the power storage device is used to drive the electric motor that drives the hydraulic pump, it is economical and easy to operate because there is no need to separately connect an external power source when heating the hydraulic oil.
Moreover, by heating the hydraulic oil tank with preheating means, convection occurs in the hydraulic oil inside the hydraulic oil tank, and the hydraulic oil inside the hydraulic oil tank is evenly warmed. The occurrence of thermal shock etc. can be prevented.

  The hydraulic oil preheating mechanism for a construction machine according to the present invention includes a temperature measuring unit that measures the temperature of the hydraulic oil in the hydraulic oil tank, and a power storage device when the temperature of the hydraulic oil measured by the temperature measuring unit is lower than a set temperature. Control means for supplying electric power to the preheating means from the engine, so that when the hydraulic oil is heated, the temperature of the hydraulic oil in the hydraulic oil tank is measured by the temperature measurement means, and the temperature of the hydraulic oil is set by the control means. When it is determined that the temperature is lower than the temperature, electric power is supplied from the power storage device to the preheating means, and when the temperature of the hydraulic oil reaches a set temperature, the supply of power from the power storage device is cut off.

  Further, the hydraulic oil preheating mechanism for a construction machine according to the present invention is provided with an electric wiring for supplying electric power from the power storage device to the preheating means, and a changeover switch capable of switching between conduction and interruption of the electric wiring, and the control means is The changeover switch is turned on when the temperature of the hydraulic oil measured by the temperature measuring means before starting the engine is lower than the set temperature, and the changeover switch is cut off when the temperature of the hydraulic oil exceeds the set temperature. Thus, by switching between conduction and interruption of the changeover switch by the control means, it is possible to control the supply and interruption of power from the power storage device to the preheating means.

It is a principal part perspective view which shows the hydraulic shovel by embodiment of this invention. It is a figure which shows the electric circuit and hydraulic oil supply system in the hydraulic shovel shown in FIG.

Hereinafter, a hydraulic oil preheating mechanism in a hydraulic excavator according to an embodiment of the present invention will be described.
1 and 2 show a hydraulic excavator according to an embodiment of the present invention.
The hydraulic excavator 1 according to the present embodiment is, for example, a hybrid hydraulic excavator, and an upper swing body 3 is turnably provided on an upper portion of a lower traveling body 2 as shown in FIG. A working machine 7 including a boom 5, an arm 6, a bucket, and the like is provided on the revolving frame 4 of the upper revolving structure 3, for example, on the front right side so as to be movable up and down.
An engine 9 and a power storage device 10 that is a battery are mounted in the upper swing body 3.

In the electric circuit diagram of the hydraulic excavator 1 according to the embodiment shown in FIG.
It is connected to a motor generator 12 having functions of a generator and a motor through a DC circuit 11 that is a transmission path. The direct current supplied from the power storage device 10 through the direct current circuit 11 is converted into alternating current by an inverter to drive the motor generator 12 as an electric motor, and the driving force of the motor generator 12 is hydraulic pumps 13 and 14 that discharge main pressure oil. Drive.
Further, when the engine 9 is driven, the motor generator 12 receives the rotational force of the engine 9 and is driven as a generator, and the generated electric power is converted into direct current and stored in the power storage device 10. The engine 9 is provided with a starter motor 15.

Further, electric actuators such as a pilot pump motor 16 for driving the pilot pump and a swing motor 17 for turning the upper turning body 3 are connected to the DC circuit 11 of the power storage device 10. The pilot pump motor 16 and the swing motor 17 also constitute a motor generator having a function as a generator.
Further, the upper swing body 3 is provided with a hydraulic oil tank 19 for supplying hydraulic oil to the hydraulic pumps 13 and 14. A heater 20 is fixed to the outer surface of the hydraulic oil tank 19 for heating the hydraulic oil in the hydraulic oil tank 19 that is in a low temperature state in a cold region or the like. The heater 20 is formed in a plate shape, for example, and is fixed to the bottom surface in FIG. 2, but may be fixed to the side surface. The hydraulic oil tank 19 is provided with a temperature sensor 21 that measures the temperature of the hydraulic oil stored inside.
In the electric circuit of the hydraulic excavator 1 shown in FIG. 2, the power storage device 10 switches and controls the supply and interruption of power to various devices such as the motor generator 12, the pilot pump motor 16, and the swing motor 17 through the DC circuit 11. An activation switch 22 is provided. In addition, the heater 20 is provided with a changeover switch 23 that performs switching control of power supply to and interruption from the power storage device 10 through the DC circuit 11.

  In addition, the electric circuit of the excavator 1 shown in FIG. 2 is provided with a control means 25 that performs electric operation control of various actuators. In particular, in the present embodiment, a temperature sensor 21 provided in the hydraulic oil tank 19 and a changeover switch 23 of the heater 20 are electrically connected to the control means 25, and the temperature of the hydraulic oil measured by the temperature sensor 21. Is lower than a predetermined temperature set in advance, the changeover switch 23 is turned on by an operation signal to operate the heater 20, and the hydraulic oil in the hydraulic oil tank 19 is heated. And when the temperature of hydraulic fluid becomes more than predetermined temperature, a stop signal is outputted from control means 25, change switch 23 is turned off, and operation of heater 20 is stopped.

The hydraulic oil preheating mechanism of the hydraulic excavator 1 according to this embodiment has the above-described configuration, and the operation thereof will be described next.
When the hydraulic excavator 1 is started, for example, in a cold region, an extremely cold region, or in winter, the hydraulic oil in the hydraulic oil tank 19 is at a lower temperature than the set value described above. Therefore, turning on the operation key turns on the operation switch 22 of the power storage device 10 without starting the engine 9. As a result, electric power is supplied from the power storage device 10 to the control means 25, the motor generator 12, and the drive system such as the pilot pump motor 16 and the swing motor 17 through the DC circuit 11.

Then, the temperature of the low temperature hydraulic oil stored in the hydraulic oil tank 19 is measured by the temperature sensor 21 and input to the control means 25. In the control means 25, when the temperature of the hydraulic oil is lower than a preset temperature, an operation signal is output and the changeover switch 23 is turned on. As a result, power is supplied to the heater 20 through the DC circuit 11 using the power storage device 10 as a power source, the hydraulic oil tank 19 is heated by the heater 20 provided in the hydraulic oil tank 19, and the hydraulic oil inside the hydraulic oil tank 19 rises in temperature.
In the hydraulic oil tank 19, convection occurs due to the heating of the hydraulic oil, and the hydraulic oil is mixed, so that it is warmed almost uniformly. Therefore, when a part of the hydraulic oil supplied into the control valve becomes high temperature, the control valve is not distorted to cause a thermal shock or the like.

When the temperature of the hydraulic oil reaches a set temperature or higher, the temperature of the hydraulic oil is detected by the temperature sensor 21, and the changeover switch 23 is turned off by an output signal from the control means 25.
Thereafter, the engine 9 is started to rotationally drive the motor generator 12 to operate the hydraulic pumps 13 and 14, so that warm hydraulic oil in the hydraulic oil tank 19 can be output to the hydraulic pumps 13 and 14. Then, the electric power generated by the rotational drive of the motor generator 12 is charged in the power storage device 10.

As described above, the hydraulic oil preheating mechanism of the hydraulic excavator 1 according to the present embodiment can warm the hydraulic oil in the hydraulic oil tank 19 by the electric power supplied from the power storage device 10 without starting the engine 9 and start the engine. Can prevent fuel consumption.
Moreover, since the convection of the hydraulic oil occurs in the heated hydraulic oil tank 19 and is heated almost uniformly, the control valve is distorted when a part of the hydraulic oil supplied into the control valve becomes high temperature, and a thermal shock or the like. Can surely be prevented.
Further, since the power storage device 10 capable of storing electricity by driving the engine 9 or the like is used as a power source for heating the heater 20 provided in the hydraulic oil tank 19, it is operated by a connection cable using an external power source when the hydraulic oil is heated at the start. There is no need to connect to the heater 20 of the oil tank 19, the configuration is simple, the operation is easy, and the increase in cost can be suppressed.

It should be noted that the present invention is not limited to the above-described embodiments, and modifications and the like can be made without departing from the spirit of the present invention, and these configurations are also included in the present invention.
For example, the heater 20 provided in the hydraulic oil tank 19 and the power storage device 10 may be electrically connected through the thermostat via the electric line 11 and held in an energized state. In this case, when the hydraulic oil in the hydraulic oil tank 19 reaches a set temperature, this temperature may be detected by a thermostat and turned off, and the DC circuit 11 may be shut off. In this case, the thermostat constitutes a control means.
Needless to say, the present invention is not limited to the hydraulic excavator 1 and can be applied to various construction machines.

DESCRIPTION OF SYMBOLS 1 Hydraulic excavator 9 Engine 10 Power storage apparatus 11 DC circuit 12 Motor generators 13 and 14 Hydraulic pump 19 Hydraulic oil tank 20 Heater 22 Operation switch 23 Changeover switch 25 Control means

Claims (4)

In a construction machine including an engine and a hydraulic oil tank that supplies hydraulic oil to a hydraulic pump,
A power storage device installed as a power source for the drive system;
A preheating means for heating the hydraulic oil in the hydraulic oil tank, and supplying the electric power from the power storage device to the preheating means to heat the hydraulic oil in the hydraulic tank. Oil preheating mechanism. Temperature measuring means for measuring the temperature of the hydraulic oil in the hydraulic oil tank;
The operation of the construction machine according to claim 1, further comprising: a control unit that supplies electric power from the power storage device to the preheating unit when the temperature of the hydraulic oil measured by the temperature measuring unit is lower than a set temperature. Oil preheating mechanism. An electrical wiring for supplying electric power from the power storage device to the preheating means, and a changeover switch that can switch between conduction and interruption of the electrical wiring are provided.
The control means conducts the changeover switch when the temperature of the hydraulic oil measured by the temperature measurement means is lower than the set temperature before starting the engine, and shuts off the changeover switch when the temperature of the hydraulic oil exceeds the set temperature. The hydraulic oil preheating mechanism according to claim 1 or 2, wherein the hydraulic oil preheating mechanism is provided. Before starting the engine, operating a power storage device installed as a power source of the drive train;
Measuring the temperature of the hydraulic oil in the hydraulic oil tank that supplies the hydraulic oil to the hydraulic pump;
And a step of heating the hydraulic oil by supplying power from the power storage device to preheating means for heating the hydraulic oil in the hydraulic oil tank when it is detected that the temperature of the hydraulic oil is lower than the set temperature. Hydraulic oil preheating method for construction machinery.

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