JP2001197785A - Circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize hydraulic energy which was hitherto discharged wastefully from a hydraulic circuit. SOLUTION: A circuit device is provided with a relief valve 52 for setting circuit pressure, within a hydraulic circuit 40, and is provided with a regenerative generator 53 which regenerates the hydraulic energy discharged via the relief valve 52 into electric energy. A constant voltage power source 54, which controls the instable voltage outputted from the regenerative generator 53 to be fixed voltage, is connected to this regenerative generator 53. Furthermore, though a battery 64 and an electric system 65 are connected to an alternator 62 which is driven together with a pump 42 by engine 41, by means of wiring 63, the wiring 66 from the output terminal of the constant voltage power source 54 is connected to this wiring 63.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit device having a relief valve.

[0002]

2. Description of the Related Art FIG. 3 shows a general hydraulic circuit in a hydraulic shovel. Rotary energy generated from an engine 11 rotates a pump 12, and hydraulic energy output from the pump 12 is controlled by a control valve 13. The flow path is switched and selected to the target actuator 14, and the flow rate is adjusted to a required value. The flow rate is input to a predetermined actuator 14, and the actuator 14 operates to move a required working device.

[0003] However, due to its structure, a hydraulic excavator is destined to always be overloaded during work. For example, as shown in FIG. 2, when digging the soil surface, when there is a hard rock R or solid soil in the soil, or because the movable range of the working device 25 is finite, the working device 25 is movable. When the robot moves to the end of the range and stops, an overload condition occurs.

[0004] As described above, when an overload occurs during the operation,
Since the pressure of the hydraulic circuit rises and causes a failure if left as it is, a relief valve 15 is provided between the pump 12 and the control valve 13 to protect the hydraulic circuit, and the circuit pressure becomes a predetermined pressure. The relief oil 15 is opened, the hydraulic oil output from the pump 12 is not supplied to the actuator 14, but is returned from the relief valve 15 to the hydraulic oil tank 17 via the bypass pipe 16, and the circuit pressure is maintained at a predetermined value. It is suppressed and the piping of the hydraulic circuit and various hydraulic equipment are protected.

[0005] However, the bypassed hydraulic energy is energy that does not perform any work, and is wasteful energy such as merely raising the oil temperature of the working oil. That is, the hydraulic energy generated by the engine 11 and output from the pump 12 is wasted at the time of overload.

On the other hand, in recent years, in order to improve the functions and comfort of hydraulic excavators, electric components and electric systems, such as an increase in the number of control devices and the installation of an air conditioner, are increasing, and their consumption is increasing. Electricity is steadily increasing.

Conventionally, as shown in FIG. 3, the alternator 18 is rotated by the rotational energy of the engine 11 to generate electric power, and the electric power is supplied to the electric system 20 while also charging the battery 19. If the power consumption of the electric system 20 increases, the load for rotating the alternator 18 increases, and the energy generated from the engine 11 is directly related to the operation of the working device 25, which is the original purpose of the hydraulic shovel. However, as the energy consumed by the electric system 20 increases, the fuel consumption of the engine 11 deteriorates and the productivity of the hydraulic shovel decreases as the energy increases.

[0008]

As described above, conventionally,
In the event of an overload condition, hydraulic energy is
From the engine 11, the power consumed by the electric system 20 is increasing, and the energy generated from the engine 11 is not only the working device 25, which is the original purpose of the hydraulic shovel, but also the alternator 18. There is a problem that a large amount of the load is consumed, fuel efficiency deteriorates, and productivity decreases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to make it possible to effectively use hydraulic energy that has been wastedly released from a hydraulic circuit as electric energy.

[0010]

According to a first aspect of the present invention, there is provided a hydraulic circuit, a relief valve for setting a circuit pressure provided in the hydraulic circuit, and a hydraulic pressure discharged through the relief valve. And a regenerative power generation device that regenerates energy into electric energy.

When the relief valve for protecting the hydraulic circuit is operated, the hydraulic energy that has been wasted from the hydraulic circuit is regenerated as electric energy by the regenerative power generator and is effectively used. .

According to a second aspect of the present invention, there is provided the circuit device according to the first aspect, further comprising a constant voltage power supply for controlling a voltage output from the regenerative power generator to a constant voltage.

[0013] The unstable voltage supplied from the regenerative power generator is controlled to a stable voltage by a constant voltage power supply and is effectively used.

According to a third aspect of the present invention, in the circuit device according to the second aspect, an engine for driving a hydraulic pressure source of the hydraulic circuit, a vehicle generator driven by the engine together with the hydraulic pressure source, A circuit device comprising: a storage battery charged by a vehicle generator; and electric equipment that operates using at least one of the vehicle generator, the storage battery, and the constant voltage power supply.

The hydraulic energy wastedly released from the relief valve of the hydraulic circuit at the time of overload is converted into electric energy by the regenerative power generator and charged by the vehicle generator or the vehicle generator. Since the electric energy supplied from the storage battery to the electric equipment is supplemented, the load on the vehicle generator is reduced, and the load on the engine that drives the vehicle generator together with the hydraulic pressure source is also reduced, and the fuel efficiency of the engine is improved. You.

According to a fourth aspect of the present invention, the circuit device according to any one of the first to third aspects is used for a construction machine having a working device.

The hydraulic energy wastedly released from the relief valve of the hydraulic circuit is regenerated as electric energy, so that the hydraulic energy consumed as electric energy is reduced and sufficient hydraulic pressure is supplied to the working device. By supplying energy, the workability of the work device is improved, and the productivity as a construction machine is improved.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS.

FIG. 2 shows a hydraulic excavator 21 as a construction machine.
In this hydraulic excavator 21, an upper revolving structure 23 is rotatably provided on a lower traveling structure 22, and the lower traveling structure 22 includes a traveling motor (not shown) as an actuator for driving the footwear 24. In addition, the upper swing body 23 has a swing motor (not shown) as an actuator for swinging and driving itself. The upper swing body 23 is provided with a working device 25.

The working device 25 includes a boom
A base end of the arm 26 is rotatably supported, a base end of an arm 27 is rotatably supported at a distal end of the boom 26, and a bucket 28 is rotatably supported at a distal end of the arm 27, The boom 26 is provided by a boom cylinder 31 as an actuator, and the arm 27 is provided by an arm cylinder as an actuator.
The bucket 28 is rotated by a bucket cylinder 33 as an actuator.

FIG. 1 shows a hydraulic circuit for operating each of the actuators (hereinafter referred to as a "hydraulic circuit").
This hydraulic circuit 40 has a pump 42 as a hydraulic pressure source driven by an engine 41 mounted on the upper swing body 23, and a pipe 43 connected to a suction port of the pump 42 The discharge port of the pump 42 is connected to a control valve 47 by a pipe 46, and is provided with a plurality of direction control and flow rate control spools in the control valve 47. The output port of the controlled hydraulic oil is connected to each of the actuators by a corresponding pipe 48.

A bypass pipe 51 is provided from a pipe 46 between the pump 42 and the control valve 47 in the hydraulic circuit 40 to a hydraulic oil tank 44, and a relief valve 52 for setting a circuit pressure is provided in the bypass pipe 51. Have been. The relief valve 52 opens when the pressure in the pipeline 46 exceeds the set pressure, discharges the hydraulic oil in the pipeline 46 to the hydraulic oil tank 44, and when the pressure in the pipeline 46 is less than the set pressure. Is closed to recover the pressure in the pipeline 46, thereby maintaining the pressure of the hydraulic oil supplied to the control valve 47 at substantially the set pressure.

In a bypass pipe 51 between the relief valve 52 and the hydraulic oil tank 44, hydraulic energy discharged to the hydraulic oil tank 44 via the relief valve 52 (hereinafter, this hydraulic energy is referred to as "hydraulic energy"). ) Is regenerated into electric energy.

The regenerative power generator 53 includes a relief valve
This is a device that generates electric power by hydraulic oil returned from the hydraulic oil tank 52 to the hydraulic oil tank 44, receives a flow of hydraulic oil by a turbine or an impeller, and converts it into rotational motion. And a DC-type or AC-type generator that is operated, and outputs power generated by the generator.

Further, a constant voltage power supply 54 for controlling the voltage output from the generator to a constant voltage is connected to the generator of the regenerative power generator 53.

The constant voltage power supply 54 controls the unstable voltage output from the regenerative power generator 53 to a set constant voltage and outputs the same. An existing step-down or step-up switching regulator is used. It is constituted by such as.

An alternator 62 as a vehicle generator driven by the engine 41 via a rotation transmitting mechanism 61 together with a pump 42 is provided. The alternator 62 is an AC generator, but includes a rectifier and outputs DC electricity.

Further, the alternator 62 has a wiring 63
, A battery 64 as a storage battery is connected, and the battery 64 is charged by the alternator 62. Further, the alternator 62 is connected by a wiring 63 to an electric system 65 having electric equipment operated by direct current electricity and electric equipment such as an air conditioner.

The output terminal of the constant voltage power supply 54 is connected to the alternator 62, the battery 64, and the electric line 65 by an electric line 66. The constant voltage output from the constant voltage power supply 54 is
Is set to be equal to or slightly higher than the terminal voltage of the battery 64.

In short, the electric system 65 is configured to operate using any one of the alternator 62, the battery 64, and the constant voltage power supply 54 as a power supply.

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

At the time of overload, the relief valve 52 opens, and the hydraulic oil bypassed through the relief valve 52 tries to return to the hydraulic oil tank 44, but activates the regenerative power generator 53 provided on the way. And then returns to the hydraulic oil tank 44.

In the regenerative power generator 53, a generator rotated by receiving the flow of hydraulic oil with a turbine or an impeller generates power. That is, the surplus hydraulic energy released from the relief valve 52 is converted into electric energy by the regenerative power generator 53.

The power output from the generator of the regenerative power generator 53 is directly supplied to the constant voltage power source 54 in the case of a DC generator.
, And in the case of an AC generator, after rectification, is input to the constant voltage power supply 54.

If the output voltage controlled by the constant voltage power supply 54 at the set voltage is set to be the same as the terminal voltage of the battery 64 or slightly higher than the terminal voltage of the battery 64, the constant voltage The electric power as the regenerative power output from the output terminal of the power supply 54 is efficiently supplied to the electric system 65, and the alternator 62 as viewed from the engine 41
The load on the device is reduced.

Therefore, at the time of overload, the wasted hydraulic energy via the relief valve 52 is regenerated by the regenerative power generator 53.
Is converted into electric energy, and is supplemented by the power supplied to the electric system 65 that consumes energy not directly related to work, so that the load on the engine 41 is reduced, fuel efficiency is improved, and Since sufficient hydraulic energy can be supplied, the workability of the working device 25 can be improved,
Productivity can be improved.

As described above, in order to protect the hydraulic system of the excavator 21, when the relief valve 52 is opened due to an overload during operation, the waste that the hydraulic energy is directly discharged to the hydraulic oil tank 44 is eliminated. The regenerative power generation device 53 converts the hydraulic energy into electric energy and regenerates it to the electric system 65, thereby reducing the engine load on the electric system 65, which is not directly related to the productivity of the excavator 21, by the regenerated electric energy. As a result, the fuel efficiency and productivity of the excavator 21 are improved.

The present invention is not limited to a hydraulic excavator, but can be applied to other construction machines or work machines having a relief valve.

[0039]

According to the first aspect of the present invention, since the hydraulic energy released through the relief valve is regenerated into electric energy by the regenerative power generator, the relief valve for protecting the hydraulic circuit operates. By doing so, the hydraulic energy that has been wastedly released from the hydraulic circuit is regenerated as electric energy by the regenerative power generation device and can be used effectively.

According to the second aspect of the present invention, the unstable voltage supplied from the regenerative power generator can be controlled to a stable voltage by the constant voltage power supply and used effectively.

According to the third aspect of the invention, the hydraulic energy that has been wastedly released from the relief valve of the hydraulic circuit at the time of overload is converted into electric energy by the regenerative power generation device, and the vehicular generator or The electric energy supplied from the storage battery charged by the vehicle generator to the electrical equipment can be supplemented, reducing the load on the vehicle generator and reducing the load on the engine that drives the vehicle generator as well as the hydraulic pressure source. Can improve the fuel efficiency of the engine.

According to the fourth aspect of the invention, the hydraulic energy wasted from the relief valve of the hydraulic circuit is regenerated as electric energy, thereby reducing hydraulic energy consumed as electric energy. Since sufficient hydraulic energy can be supplied to the working device, workability by the working device can be improved, and productivity as a construction machine can be improved.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a circuit device according to the present invention.

FIG. 2 is an explanatory diagram showing a working state of a hydraulic shovel.

FIG. 3 is a circuit diagram showing a conventional circuit device.

[Explanation of symbols]

 21 Hydraulic excavator as a construction machine 25 Working equipment 40 Hydraulic circuit (hydraulic circuit) 41 Engine 42 Pump as a hydraulic pressure source 52 Relief valve 53 Regenerative generator 54 Constant voltage power supply 62 Alternator as a vehicle generator 64 As a storage battery Battery 65 Electric system with electrical equipment

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2D003 AA01 AB06 AB07 BA02 BA05 CA09 CA10 DA04 3H089 AA02 BB04 CC11 DA13 DA20 DB03 DB32 GG02 JJ01 5H590 AA02 CA23 CA30 CC01 CC11 CD01 CE05 EA13 EB02 FA01 FA05 FA08 GA02 HA02

Claims (4)

[Claims] A hydraulic circuit, a relief valve provided in the hydraulic circuit for setting circuit pressure, and a regenerative power generator for regenerating hydraulic energy released through the relief valve into electric energy. A circuit device characterized in that: 2. The circuit device according to claim 1, further comprising a constant voltage power supply for controlling a voltage output from the regenerative power generator to a constant voltage. 3. An engine for driving a hydraulic pressure source of a hydraulic circuit, a vehicular generator driven by the engine together with the hydraulic pressure source, a storage battery charged by the vehicular generator, a vehicular generator, and a storage battery 3. The circuit device according to claim 2, further comprising an electric device that operates using at least one of a constant voltage power supply as a power supply. 4. The circuit device according to claim 1, wherein the circuit device is used for a construction machine having a working device.