JP4192123B2 - Power generation circuit of lifting magnet device - Google Patents

Description

  The present invention relates to a power generation circuit of a lifting magnet device, and more particularly to a power generation circuit of a lifting magnet device capable of causing a lifting magnet installed in a construction machine to perform a stable operation.

  As a conventional technique relating to driving of a lifting magnet equipped in a construction machine, for example, the following hydraulic drive apparatus for a generator of a construction machine is known. This prior art is driven by an engine mounted on a construction machine, and has an independent hydraulic pump and a variable displacement hydraulic motor for driving a generator, apart from a main pump for driving a hydraulic actuator of the construction machine body. In a hydraulic drive device for a generator of a construction machine, two types are set: a P mode in which the engine is operated at a high speed during a relatively high load operation, and an E mode in which the engine is operated at a low speed with emphasis on fuel consumption. A setting unit, and a control device that controls the rotation of the variable displacement hydraulic motor to be constant by changing the tilt angle of the variable displacement hydraulic motor in accordance with the setting of each mode by the setting unit; Even when the engine speed changes, the speed of the generator can be kept constant (see, for example, Patent Document 1).

In addition, as another conventional technique related to driving of a lifting magnet equipped in a construction machine, for example, the following hydraulic circuit for a lifting magnet generator is known. In this prior art, a hydraulic pump is connected to an engine, a hydraulic motor is connected to a lifting magnet generator, a hydraulic pump and a hydraulic motor are connected via a control valve, and the hydraulic pump and hydraulic pressure are switched by switching the control valve. It is configured so that connection and disconnection with the motor can be performed (for example, see Patent Document 2).
JP 2002-349503 (pages 2 to 4, FIG. 1). Japanese Utility Model Publication No. 61-21774 (first page, FIG. 1).

  In the prior art described in Patent Document 1, when the engine speed changes only in two ways: a high engine speed during relatively high-load work and a low engine speed that emphasizes fuel efficiency, the generator engine speed is changed. Can be kept constant.

  Further, in the prior art described in Patent Document 2, only a generator hydraulic pump is connected to the engine, and when the engine load changes, means for keeping the generator rotational speed constant is as follows. There is no disclosure.

  By the way, in a construction machine such as a hydraulic excavator equipped with a lifting magnet, a hydraulic pump for a generator and a hydraulic pump for a work device that drives a work device such as various hydraulic actuators have a common drive system by one engine. Is common. When the lifting magnet is actuated, it is normal that a combined operation state in which other working devices such as a hydraulic actuator are simultaneously actuated. Therefore, during such a combined operation, fluctuations in the engine rotation are likely to occur due to load fluctuations. For this reason, if fluctuations occur in the rotation of the generator and the power supply to the lifting magnet becomes unstable, the suspended load may be dropped or the lifting magnet control device may be damaged.

  Therefore, there is a technical problem to be solved in order to supply stable power from the generator to the lifting magnet and cause the lifting magnet to perform a stable operation, and the present invention solves this problem. For the purpose.

The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 includes a diesel engine that drives a plurality of hydraulic pumps including a generator hydraulic pump, and the generator hydraulic pump. In a power generation circuit of a lifting magnet device having a driven hydraulic motor and a generator that is driven by the hydraulic motor and generates electric power for exciting a lifting magnet,
A control unit for calculating a control signal for controlling the rotational speed to a set constant value based on at least a detected value and a set number of engine rotational speeds in the diesel engine detected by a rotational sensor attached to the diesel engine; Have
The diesel engine includes an electronic governor that adjusts a fuel injection amount in a fuel injection pump in the diesel engine according to the control signal and holds the engine speed at a set constant speed ,
Power generation Configured formed Ru lifting magnet device such that the engine speed is driven at a constant rotational speed generator is set via the hydraulic pump and the hydraulic motor generators by being held constant rotational speed Provide a circuit.

  According to this configuration, the engine speed is detected by the rotation sensor attached to the diesel engine. The detected engine speed signal is input to the control unit together with the set speed signal, and the control unit outputs a control signal for controlling the engine speed to a set constant speed based on these input signals. Calculated. This control signal is sent to the electronic governor, and the fuel injection amount in the fuel injection pump is adjusted by the electronic governor according to the control signal, and the engine speed is held at a set constant speed.

  The invention according to claim 1 has a control unit that calculates a control signal for controlling the engine speed to a set constant value based on at least a detection value and a set speed of the engine speed in a diesel engine, The diesel engine includes an electronic governor that adjusts the fuel injection amount of the fuel injection pump in the diesel engine according to the control signal and holds the engine speed at a set constant speed. The fuel injection amount in the fuel injection pump is adjusted according to the control signal calculated by the control unit, and the diesel engine has almost no fluctuation in the engine speed due to the fluctuation of the load, and the engine speed is set to a fixed speed. By being held, stable power can be supplied from the generator to the lifting magnet. There is an advantage that it is possible to perform a stable operation in computing the magnet.

  A diesel engine that drives a hydraulic pump for a generator and a hydraulic pump for a working device, and the generator for supplying the lifting magnet with stable power from the generator and causing the lifting magnet to perform a stable operation Generator circuit for a lifting magnet device, comprising: a hydraulic motor driven by a hydraulic pump for power generation; a generator driven by the hydraulic motor to generate AC power; and a rectifier that converts the AC power into DC power for lifting magnet excitation A control unit that calculates a control signal for controlling the engine speed to a set constant value based on at least each detected value of the engine speed and cooling system temperature in the diesel engine and a set speed. A diesel engine has a fuel injection port in the diesel engine. Realized by equip an electronic governor for holding the fuel injection amount of up to a constant speed set the engine rotational speed adjusted according to the control signal.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a circuit diagram of the present embodiment. FIG. 2 is a side view of a hydraulic excavator as an application example of the present embodiment. The power generation circuit of the lifting magnet device of this embodiment is applied to a hydraulic excavator as a construction machine.

  The configuration of the power generation circuit of the lifting magnet device according to the present embodiment will be described from an application example to the hydraulic excavator in FIG. As shown in the figure, the excavator 1 has an upper swing body 4 mounted on a lower traveling body 2 via a swing mechanism 3 so that the upper swing body 4 can swing, and a cab 5 is mounted on one front side of the upper swing body 4. Is provided.

  Further, the excavator 1 is equipped with the following mechanisms as work devices. In other words, the boom 6 is attached to the front center portion of the upper swing body 4 so as to be able to move up and down, and the arm 7 is attached to the tip of the boom 6 so as to be rotatable up and down. A lifting magnet 8 is attached to the tip of the arm 7. A boom cylinder 6 a is attached between the upper swing body 4 and the boom 6, and an arm cylinder 7 a is attached between the boom 6 and the arm 7. A lifting magnet cylinder 8 a is attached between the arm 7 and the lifting magnet 8.

  Next, the configuration of the power generation circuit of the lifting magnet device will be described with reference to FIG. A hydraulic pump 10 for a working device and a hydraulic pump 11 for a generator for driving the cylinders 6a to 8a as working devices in the hydraulic excavator 1 on a drive shaft of a diesel engine 9 mounted on the hydraulic excavator 1. Are commonly installed.

  The diesel engine 9 is provided with a fuel injection pump and an electronic governor 12 that adjusts the fuel injection amount in the fuel injection pump via a rack actuator. The diesel engine 9 is provided with a rotation sensor 13 for detecting the engine speed and a temperature sensor for detecting the temperature of a cooling system (not shown). Sensor output lines of these sensors are connected to the control unit 14. ing. The controller 14 is connected to a set speed signal line from an accelerator operating device 15 for setting the engine speed.

  The controller 14 incorporates a ROM that stores an output control map for these sensor signals, a CPU for calculation, and the like. Based on these sensor signals, the control unit 14 adjusts the fuel injection amount of the fuel injection pump in the diesel engine 9 to calculate a control signal for controlling the engine speed to a set constant value. The signal output line is connected to the electronic governor 12.

  An oil passage for pressure oil discharged from the generator hydraulic pump 11 is connected to a hydraulic motor 16. The hydraulic motor 16 is connected to a generator 17 that is driven by the hydraulic motor 16 and generates AC power. The output terminal of the generator 17 is connected to the lifting magnet 8 via a rectifier 18 that converts the generated AC power into DC power for lifting magnet excitation.

  Next, the operation of the power generation circuit of the lifting magnet device configured as described above will be described. The engine speed is detected by a rotation sensor 13 attached to the diesel engine 9. The detected engine speed signal is input to the control unit 14 together with the set speed signal set by the accelerator operating unit 15, and the engine speed is set by the control unit 14 based on these input signals. A control signal for controlling to a constant rotational speed is calculated.

  The calculated control signal is sent to the electronic governor 12, and the electronic governor 12 adjusts the fuel injection amount in the fuel injection pump according to the control signal via the rack actuator, and sets the engine speed. It is held at a constant rotational speed. Therefore, by maintaining the engine speed at the set constant speed, the generator 17 is driven at the set constant speed via the generator hydraulic pump 11 and the hydraulic motor 16, and the generator 17 is driven. AC power of a predetermined magnitude is generated from This AC power is converted into DC power by the rectifier 18, and DC power that is stable at a predetermined magnitude is supplied to the lifting magnet 8.

  Then, while the actuator of the working device such as the boom cylinder 6a, the arm cylinder 7a, and the lifting magnet cylinder 8a is driven by the working device hydraulic pump 10, the lifting magnet 8 can safely perform work such as adsorption and transportation of the object. .

  As described above, in the power generation circuit of the lifting magnet device according to the present embodiment, the fuel injection amount in the fuel injection pump is adjusted by the electronic governor 12 according to the control signal calculated by the control unit 14, and the diesel engine No. 9 has almost no fluctuation in engine speed due to fluctuations in loads such as other work devices, and the engine speed is held at a set constant speed so that the lifting magnet 8 is stabilized from the generator 17. Electric power can be supplied, and the lifting magnet 8 can be operated stably.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

The circuit diagram of the electric power generation circuit of the lifting magnet apparatus which concerns on the Example of this invention. The side view of the hydraulic shovel which is an application example of the said Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 8 Lifting magnet 9 Diesel engine 10 Hydraulic pump for working devices 11 Hydraulic pump for generators 12 Electronic governor 13 Rotation sensor 14 Control unit 16 Hydraulic motor 17 Generator

Claims (1)

A diesel engine that drives a plurality of hydraulic pumps including a generator hydraulic pump; a hydraulic motor that is driven by the generator hydraulic pump; and a generator that is driven by the hydraulic motor and generates electric power for exciting a lifting magnet; In the power generation circuit of the lifting magnet device having
A control unit for calculating a control signal for controlling the rotational speed to a set constant value based on at least a detected value and a set number of engine rotational speeds in the diesel engine detected by a rotational sensor attached to the diesel engine; Have
The diesel engine includes an electronic governor that adjusts a fuel injection amount in a fuel injection pump in the diesel engine according to the control signal and holds the engine speed at a set constant speed ,
Wherein the configuration has been formed Rukoto as the engine speed is driven at a constant rotational speed generator is set via the hydraulic pump and the hydraulic motor generators by being held constant rotational speed Power generation circuit of lifting magnet device.

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