JP6109811B2 - Excavator - Google Patents

Description

  The present invention relates to an excavator that drives a swivel unit including a boom, an arm, and a bucket to swivel.

  Conventional power shovels have the configurations shown in FIGS. 5 and 6. First, as shown in FIG. 5, a hydraulic circuit pump 41 is driven by an engine 40, and a hydraulic pressure generated by the pump 41 is used to drive a work machine drive hydraulic cylinder 44, a hydraulic swing motor 43, and hydraulic travel through a control valve 42. The motor 46 was driven. In addition, 45 is a center joint, 48 is a traveling part, 49 is a turning part, 50 is a working part.

  FIG. 6 is a block diagram showing the hydraulic system. The hydraulic circuit constituting this system is directly connected to the control valve 42 from the hydraulic pump 41 coupled to the engine 40, and is supplied to and discharged from the control valve 42 to the hydraulic cylinder 44, and is supplied to and discharged from the hydraulic swing motor 43. The circuit for supplying and discharging the hydraulic travel motor 46 was connected.

  In this circuit, multiple target simultaneous control of actuators such as various hydraulic motors 43 and 46 and a hydraulic cylinder 44 constituting a load is performed on a hydraulic pump 41 which is a pressure source. Also, 47 is a hydraulic oil tank, 48 is a traveling part, 49 is a turning part, 50 is a working part (boom, arm, bucket), and the hydraulic system has a high-pressure circuit part because it needs to generate a driving force. It was.

  However, the hydraulic circuit as described above has problems of oil leakage from the connecting portion, poor responsiveness based on the expansion and contraction characteristics of oil, and difficulty in control due to control and switching impacts.

  Further, in the hydraulic drive system as described above, when the driver operates the operation lever, the hydraulic horsepower is distributed according to the load of the actuator and the opening characteristics of the hydraulic valve, so that the pressure oil can easily flow to the lightly loaded actuator. Since the operation of the entire machine can be biased, the operator has to adjust with the operation lever each time.Therefore, there are problems such as poor operability due to insufficient pump flow pressure during simultaneous control of multiple loads. there were.

  In view of the above situation, an object of the present invention is to provide an excavator that improves the responsiveness and operability, and that drives the swivel unit including the boom, the arm, and the bucket to swivel.

In the present invention, in order to achieve the above object, in the excavator that drives the swivel unit including the boom, the arm, and the bucket to swivel,
DC power supply,
A converter connected to the DC power source;
A voltage / current detector provided between the DC power source and the converter;
A first inverter connected to the converter;
A second inverter connected to the converter;
A turning electric motor that is a drive source of a turning drive device connected to the first inverter;
A control device for controlling the converter, the first inverter, and the second inverter;
A capacitor provided in common between the converter and the first inverter, between the converter and the second inverter, and
The voltage value and current value detected by the voltage / current detector are input to the control device,
The control device controls the converter based on a voltage value of the DC power supply and a current value of the DC power supply .

  Therefore, according to the excavator that drives the swing portion including the boom, arm, and bucket, the controller performs a predetermined calculation in accordance with the operation setting of the operation lever, and the calculation result is highly accurate and individually controlled by the inverter. In response to the motor, each motor can be controlled with good responsiveness.

  Further, since both the inverters can be operated in parallel with any setting by the controller, a combined operation of driving of the work machine actuator and driving of the swing drive device can be easily performed.

  Furthermore, since the rotation speed of the electric motor is detected by the encoder, the detected data can be made into code data that can be easily processed by the controller.

  The present invention uses an AC motor having good responsiveness and operability for each drive source, and an AC motor and a turning AC motor that drive an actuator for a work machine via power control means including a converter and an inverter that can be individually controlled. As a result, the simultaneous control of multiple loads, which was not easy with conventional hydraulic drive, has become easier. In addition, since the simultaneous control of multiple loads has become easier, the operability during combined operations has been greatly improved.

  The mode switch enables a wide range of work modes to be selected, improving operability in combination with the setting operation of the control lever. Since the output of the inverter is a harmonic output, the control output can be finely divided and the control input can be finely set by the amount of the harmonic.

It is a schematic diagram of the construction machine of 1st Example of this invention. It is a block diagram of the electric power control system in 1st Example of this invention. It is a block diagram of the control system of the whole machine in 1st Example of this invention (a dotted line part is a part of 2nd Example). It is a schematic diagram of the construction machine (crane) which shows the reference example of this invention. It is a hydraulic system block diagram including arrangement | positioning in the conventional hydraulic shovel. It is a hydraulic system block diagram in the conventional hydraulic excavator.

  Hereinafter, the present invention will be described with reference to the drawings showing embodiments thereof. (First Embodiment) FIG. 1 is a schematic diagram of a shovel showing a first embodiment of the present invention, FIG. 2 is a block diagram of a power control system for the motor of the shovel, and FIG. 3 is a control of the whole. It is a block diagram of a system.

  In FIG. 2, reference numeral 1 denotes a power source which can be used for both alternating current and direct current. A voltage / current detector 2 detects a power supply voltage and a power supply current.

  Reference numeral 3 denotes a converter (converter) having a function of converting the power output to direct current. Reference numerals 4 and 5 denote inverters (converters) that convert the output of the converter 3 into a high-frequency AC output. Reference numerals 6 and 7 denote voltage / current detectors which detect the output voltage and output current of the inverters 4 and 5. Reference numerals 8 and 10 denote AC (alternating current) motors, which are induction motors having characteristics suitable for being driven by an inverter. Reference numerals 9 and 11 denote encoders which detect the rotational speeds of the AC motors 8 and 10 and output code data.

  Reference numeral 12 denotes a mode switch, which makes it possible to select the power input ratio to the work machine and the turning motor / motor generator in a plurality of work patterns by the mode selection function, and to set various modes by program control of the controller 14. For example, a standard mode in which electric power is evenly distributed to each motor during combined operation, a work machine priority mode in which power is allocated with priority given to work machine speed, a turn priority mode in which power is allocated with priority given to turning speed, and a work machine part Also, it is possible to set the speed compensation mode, etc., which limits the speed to the turning part, such as constant speed, maximum speed restriction, etc. It is an input means for selecting an operation mode such as a corresponding shift mode. The operator can select the mode according to the work condition and the skill level, and can secure the most easy operation condition, thereby improving the work efficiency.

  An operation lever 13 outputs various setting operation signals according to the operation. Separate operating levers for the work machine and for turning may be provided, or may be shared. Further, it may be interlocked with the mode switch 12.

  Reference numeral 14 denotes a controller (control device) having a programmable CPU, and based on detection data from the voltage / current detectors 2, 6, 7 and the encoders 9, 11, inputs from the mode switch 12 and the operation lever 13 In response, converter 3 and inverters 4 and 5 are controlled to control AC motors 8 and 10 individually or in parallel.

  Reference numeral 27 denotes a condenser.

  FIG. 3 is a block diagram of the entire control system (dotted line portion is a reference example portion).

  In this figure, the controller 14 basically comprises an input / output port, a CPU, and a memory. The input port includes an operation lever 13, encoders 9 and 11, voltage / current detectors 2, 6, and 7, an expansion / contraction detection sensor 15 that detects an expansion / contraction state of an actuator for a work machine such as a boom, arm, bucket, etc., load detection A sensor 16, a turning angle detection sensor 17, and a mode switch 12 are connected. The output port is connected to the converter 3, inverters 4 and 5, and the monitor device 18.

  The operation of the excavator of the first embodiment configured as described above will be described below.

  First, the mode switch 12 sets the drive mode of the work machine AC motor 8 and the turning AC motor 10 of the controller 14 and registers them in the memory. Next, a setting operation signal is output by operating the operation lever 13. The controller 14 takes in the operation setting signal, rotation speed data from the encoders 9 and 11, voltage values and current values from the voltage / current detectors 2, 6 and 7, and searches a table stored in the memory Then, a predetermined program is executed to control the converter 3 and the inverters 4 and 5 such as frequency control, phase control, duty ratio control, etc., and cause the AC motors 8 and 10 to perform predetermined operations. Since the outputs of the inverters 4 and 5 are harmonic outputs, the control output can be finely set and the control input can be finely set, and the operability is good.

(Operation mode of AC electric motor for work equipment)
The controller 14 changes the output of the inverter 4 in accordance with the setting operation signal of the operation lever 13, and drives the work machine AC motor 8 to perform expansion and contraction drive of the boom, arm, and bucket.

  At this time, based on the detection data of the expansion / contraction detection sensor 15, for example, the controller 14 controls to increase the linear speed at the beginning of the expansion / contraction operation, to a constant speed in the middle, and to decrease the speed at the end. Thereby, soft start and soft landing can be achieved. Further, the controller 14 can control the speed of the work machine AC electric motor 8 according to the detection data of the load detection sensor 16, that is, when the load is light, the speed is increased, and when the load is heavy, the speed is decreased.

(Operation mode of AC motor for turning)
The controller 14 changes the output of the inverter 5 in accordance with the setting operation signal of the operation lever 13 to drive the turning AC electric motor 10 to turn the work implement.

  At that time, the output of the turning angle detection sensor 17 per unit time is calculated, the detection data of the load detection sensor 16 is obtained, and the inertial force of the working unit is calculated from these, and this inertial force is within a predetermined range. The turning AC motor 10 is controlled so as to be within the range. Further, when the constant speed control is set by the setting operation signal of the operation lever 13 and the mode switch 12, the controller 14 controls the inverter 5 while reading the detection data of the encoder 11 to set the turning AC motor 10. Speed control.

(Operation mode of compound operation)
In the combined work of the work machine AC motor 8 and the turning AC motor 10, for example, the controller 14 detects the turning AC motor 10 by detecting the turning angle detection sensor 17 and the encoder 11 in order to facilitate the work. The inverters 4 and 5 can be controlled so that the work machine AC motor 8 is driven at a speed according to the set operation signal of the operation lever 13 while being driven at a constant speed.

  In addition, the controller 14 controls the inverters 4 and 5 so as to operate the work machine AC motor 8 and the turning AC motor 10 in relation to an arbitrary relationship by setting operation signals of the operation lever 13 and the mode switch 12. be able to.

  FIG. 4 is a schematic diagram of a construction machine (crane) shown as a reference of the present invention. The winding detection sensor in this reference example is indicated by a dotted line in FIG. As shown in this figure, the construction machine (crawler crane) includes an AC electric motor 21 for lifting and lifting electric winch (for working machine), an AC electric motor 22 for boom hoisting electric winch (for working machine), and an AC electric motor for turning. 23, and the converter is controlled in the same manner as in the first embodiment based on the output of the winding detection sensor 19. In addition, 24 is an electric motor for driving | running | working, 25 is a boom, 26 is a hook.

(Other embodiments)
The power source includes a generator coupled to the engine, a fuel cell, a commercial power source, etc., and these battery backups are also selectively performed. If a second stage converter is connected to the subsequent stage of the inverter, a DC (direct current) motor, a pulse motor or the like can be used as the motor. The operation lever 13 and the mode switch 12 can be replaced with wireless or wired remote operation means as alternative means. In addition, this invention is not limited to the said Example, A various deformation | transformation is possible based on the meaning of this invention, and these are not excluded from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Power supply 2, 6, 7 Voltage / current detector 3 Converter 4, 5 Inverter 8 Work machine AC motor 9, 11 Encoder 10 Turning AC motor 12 Mode switch 13 Operation lever 14 Controller (control device)
DESCRIPTION OF SYMBOLS 15 Expansion / contraction detection sensor 16 Load detection sensor 17 Turning angle detection sensor 18 Monitor apparatus 21 AC electric motor for electric lifting winch (for working machines) 22 Electric motor for boom hoisting (for working machines) AC electric motor 23 Turning AC electric motor 24 Electric motor 25 for traveling 25 Boom 26 Hook 27 Condenser

Claims (5)

In an excavator that drives a swivel unit including a boom, an arm, and a bucket to swivel,
DC power supply,
A converter connected to the DC power source;
A voltage / current detector provided between the DC power source and the converter;
A first inverter connected to the converter;
A second inverter connected to the converter;
A turning electric motor that is a drive source of a turning drive device connected to the first inverter;
A control device for controlling the converter, the first inverter, and the second inverter;
A capacitor provided in common between the converter and the first inverter, between the converter and the second inverter, and
The voltage value of the DC power source detected by the voltage / current detector, the current value of the DC power source is input to the control device,
The control device is an excavator that controls the converter based on the voltage value and the current value. An encoder that detects the number of rotations of the electric motor for turning and uses detection data as code data;
A current detector is provided between the first inverter and the turning electric motor;
The detection value of the current detector is input to the control device,
The control device performs predetermined calculation processing based on a setting operation signal from an operation lever and the encoder, and changes the output of the first inverter based on the calculation result, thereby controlling the speed of the turning electric motor. The shovel according to claim 1.   The excavator according to claim 1, wherein the control device performs any one of frequency control, position control, and duty control for the converter. It has an electric motor for work equipment,
The excavator according to any one of claims 1 to 3, wherein the control device has a plurality of control modes and selects a power input ratio to the electric motor for the working machine and the electric motor for turning.   The excavator according to any one of claims 1 to 4, wherein the control device performs any one of frequency control, position control, and duty control on each of the inverters.

Images