Hangzhou Daji

Abstract

To provide a pile driver capable of supplying power necessary for hydraulic drive and electric drive without increasing the size of the on-board generator even when a conventionally mounted generator is used. In a pile driver equipped with a hydraulic device that serves as a hydraulic source for driving an auger 18 up and down and a power source for rotating the auger, the hydraulic device comprises an electric motor 37 that receives power from the power source, a hydraulic pump 38 that is driven by the electric motor, an inverter 39 that controls the rotation speed of the electric motor, a controller 30 that controls the inverter, and a load P of the electric motor. M The motor load detector detects the load P O The controller detects the load amount P detected by the motor load detection unit and the auger load detection unit. M ,P O The sum of the power supply output P G When it is judged that the load amount P of the electric motor exceeds M Control is performed to limit the

Description

[Technical Field]

[0001] The present invention relates to a pile driver, and more particularly to a pile driver equipped with an excavation auger that is rotationally driven by receiving power from a power source. [Background technology]

[0002] Large three-point support pile drivers are repeatedly disassembled and reassembled each time they are transported to a site to meet transportation restrictions such as size and weight. After assembly, hydraulic power is obtained from an engine-driven hydraulic pump, enabling the vehicle to perform various operations such as traveling, turning, and winching. The auger, which has an electric rotation control system, is wired to receive power from a generator mounted on the rear frame of the pile driver (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-167770 Summary of the Invention [Problem to be solved by the invention]

[0004] From an environmental perspective, some have proposed equipping pile drivers with electric motors instead of engines, using the electric motor to drive the hydraulic pump. When electrifying such pile drivers, it would be desirable to configure them to be powered by commercial power, which would eliminate reliance on an internal combustion engine. However, due to issues such as the location of the construction site and preparation, no effective technology has yet been established to address the obstacles to using commercial power. However, even with this in mind, designing a generator to accommodate all of the pile driver's load conditions while still incorporating an electric motor would require an increased generator size, limiting the feasibility of the vehicle.

[0005] Therefore, the present invention aims to provide a pile driver that can supply the power necessary for hydraulic drive and electric drive without increasing the size of the onboard generator, even when using a generator that has traditionally been installed. [Means for solving the problem]

[0006] To achieve the above object, the present invention provides a pile driver comprising: a base machine having a rotatable upper rotating body mounted on a lower traveling body; a leader mounted on the front of the upper rotating body so as to be able to rise and fall; an auger that can be raised and lowered along the front surface of the leader; a hydraulic device that serves as a hydraulic source for driving the auger to rise and fall; and a power source for rotating the auger. The hydraulic device includes an electric motor receiving power from the power source, a hydraulic pump driven by the electric motor, an inverter controlling the rotation speed of the electric motor, a controller controlling the inverter, a motor load detector that detects the load on the electric motor, and an auger load detector that detects the load on the rotational drive of the auger. The controller is configured to limit the load on the electric motor when it determines that the sum of the loads detected by the motor load detector and the auger load detector exceeds the output of the power source. The power source is a diesel generator mounted on the pile driver. [Effects of the Invention]

[0007] According to the pile driver of the present invention, if it is determined that the total load detected by the motor load detector and the auger load detector exceeds the output of the power supply, control is performed to limit the load on the electric motor, so that the generated power can be allocated to the rotation drive and the lift drive within the load fluctuation range without interrupting the excavation work (stopping rotation).This means that even when using a conventional on-board generator, it is possible to eliminate the engine without increasing the size of the on-board generator, resulting in a pile driver that is more environmentally friendly than conventional ones. [Brief explanation of the drawings]

[0008] [Figure 1]1 is a side view of a pile driver showing an example of an embodiment of the present invention. [Figure 2] FIG. [Figure 3] FIG. DETAILED DESCRIPTION OF THE INVENTION

[0009] Figures 1 to 3 show one example of a pile driver of the present invention. As shown in Figures 1 and 2, the pile driver 11 is equipped with a base machine 14 consisting of a lower running body 12 equipped with crawlers and an upper rotating body 13 rotatably mounted on the upper part of the lower running body 12, a leader 15 that can be raised and lowered and mounted on the front part of the upper rotating body 13, a pair of left and right guide pipes 16, 16 mounted on the front side of the leader 15 parallel to the longitudinal direction of the leader 15, and an auger (rotary drive device) 18 that can be raised and lowered along the front surface of the leader 15 via a plurality of guide gibs 17 that slidably hold both guide pipes 16, 16.

[0010] A cab 19 for the operator is located on the right side of the upper rotating body 13, and a house 20 housing various components constituting the hydraulic system (described later) is located on the left side. A plurality of winch devices 21, including a main winch and an auxiliary winch, are provided in the center of the upper rotating body 13. At the rear of the upper rotating body 13, a counterweight 22, a platform 24 on which a portable diesel generator (hereinafter referred to as the generator) 23 serving as an example of a power source is mounted, a gantry 25, and a pair of left and right backstays 26, 26 supporting the leader 15 are provided. A main hoisting rope 27 from the main hoisting winch is connected to a sheave on the auger 18 via a sheave in a top sheave 28 located at the top of the leader 15, and the auger 18 can be raised and lowered by operating the main hoisting winch. Stabilizing jacks 29 are provided at four locations on the front, rear, left, and right sides of the upper rotating body 13.

[0011] Within the cab 19, devices such as control levers, control pedals, and displays for various hydraulic system operations such as traveling, swinging, hoisting, and lowering are concentrated near the driver's seat for ease of use, and a controller (control device) 30 electrically connected to these devices is also provided (see Figure 3).In addition, a control panel (not shown) for operating the auger 18 and monitoring its operating status is provided at an appropriate position within the cab, and this control panel is wired to an inverter 31 installed at the front of the house 20.

[0012] The inverter 31 is connected between the generator 23 and the auger 18 by a power transmission cable. Specifically, a primary cable 32 is connected to the generator 23, and a secondary cable 33 is connected to the auger 18. The primary cable 32 is connected to the output terminal of the generator 23 and routed along the outer surface of the house 20. Meanwhile, the secondary cable 33 is suspended by a cable support 34 provided in the middle of the leader 15, and is therefore movable up and down in accordance with the lifting and lowering movement of the auger 18. The length of the secondary cable 33 is set to be long enough to allow the auger 18 to reach the upper part (upper limit position) and lower part (lower limit position) of the leader 15.

[0013] The inverter 31 controls the rotation of the auger 18 in response to commands from the operation panel. Accordingly, the auger 18 receives power from the generator 23, which rotates the built-in electric motor at a rotation speed and torque suitable for the working conditions. As a result, in interaction with the downward movement (hydraulic drive) of the auger 18, the screw rod 35 connected to the output shaft of the auger reducer 18a rotates integrally with the casing 36 that covers its outer periphery and is pushed into the ground, thereby forming a borehole in the ground that corresponds to the diameter of the screw rod 35.

[0014] The hydraulic device is a hydraulic source for driving hydraulic actuators of various parts such as the jack 29, the lower traveling body 12, the upper rotating body 13, and the winch device 21, and as shown in FIG. 3, includes an electric motor 37 supplied with power from the generator 23, a hydraulic pump 38 driven by the electric motor 37, an inverter 39 for controlling the rotation speed of the electric motor 37, a controller 30 for controlling the inverter 39, and a load P M and a motor load detector (not shown) for detecting the load P O The auger load detector (not shown) is configured to detect the load of the auger.

[0015] The controller 30 is mainly composed of a CPU that performs various calculations, such as data processing and judgment, based on the operator's operation commands and the status of the pile driver 11, and controls the system in an integrated manner in cooperation with a construction management device (not shown). The inverter 39 is connected to the generator 23 via a primary cable 40 and to the electric motor 37 via a secondary cable 41. The primary cable 40 is connected to the output terminal of the generator 23 and is pulled into the house 20. The inverter 39 also controls the rotation of the electric motor 37 in response to commands from the controller 30. Accordingly, the electric motor 37 is rotated at a set rotation speed and torque, driving a hydraulic pump 38 connected to the output shaft to generate the hydraulic pressure required to drive various hydraulic actuators.

[0016] The motor load detector and the auger load detector may use, for example, a power meter attached to the secondary cables 33, 41. The power meter measures voltage and current using a voltage transformer (VT) and a current transformer (CT), and calculates the load amount P M ,P O The controller 30 calculates the power consumption as follows: The load amount P M ,P O The sum of these is the output (rated output) of generator 23, P GWhen it is determined that the load amount P of the electric motor 37 exceeds M Specifically, the controller 30 executes a control program to read and refer to the output data of the generator 23 from the memory, and calculates the load P of the electric motor 37 based on, for example, the following equation (1): M Limit.

[0017] P G >P M +P O ...Formula 1 P M : Load of the electric motor 37 P G : Output of generator 23 P O :Auger 18 load

[0018] For example, when preparing for excavation work, the pile driver 11 sends fluid power generated by the hydraulic device to the hydraulic actuators of the lower traveling body 12, the upper rotating body 13, the jack 29, and other parts that are driven in sequence, in a timely and appropriate manner. At this time, the load P caused by the traveling drive is M becomes relatively large, but in this state, the auger 18 is not driven (load amount P O Therefore, the pile driver 11 at the time of setup operates at the output P G It works well enough.

[0019] On the other hand, during excavation work, the work is performed while remaining in one place, so no load is generated due to the lower traveling body 12, the upper rotating body 13, etc., and the auger 18 is rotated and lowered simultaneously (pushed in state), and the load amount P due to the driving of the auger 18 and the winch device 21 is O ,P M The sum of the output of generator 23 is P G At this time, the load P caused by the winch drive is kept within the range of M is basically small, and the magnitude relationship of the generated load is M <P OHere, at the start of excavation, the excavation is carried out with emphasis on efficiency, but if the soil to be excavated changes from soft ground to hard ground, the auger 18 will be operated in a high torque state.

[0020] In response to such changes in the driving state of the auger 18, the controller 30 performs load limiting control to prevent the generator 23 from exceeding its capacity. For example, when the load amount P M ,P O The sum of the output of generator 23 is P G If it is determined that the load amount P of the electric motor 37 exceeds the load amount P of the electric motor 37, the output frequency of the inverter 39 is quickly reduced to suppress the rotation speed of the electric motor 37. M The output of the auger 18 (load P O In addition, by temporarily reducing the descending speed of the auger 18, the auger 18 approaches a state where only rotation is being driven (in-place rotation state), so even when hard ground is reached, it is possible to ensure that excavation is carried out over a long period of time while avoiding an overload state.

[0021] In this way, according to the pile driver 11 of the present invention, the load amount P detected by the motor load detection unit and the auger load detection unit M ,P O The sum of these is the output P of the power source (generator 23) G When it is determined that the load amount P of the electric motor 37 exceeds M Since control is performed to limit the load, it is possible to avoid interruptions to excavation work (stopping of rotation) and allocate generated power to the rotation drive of the electric auger 18 for excavation and the lift drive of the auger 18 by the hydraulic pump 38 within the load fluctuation range. As a result, even when using a conventionally equipped generator 23, it is possible to eliminate the engine without increasing the size of the equipped generator 23, thereby realizing a pile driver 11 that is more environmentally friendly than conventional ones.

[0022] The present invention is not limited to the above-described exemplary embodiments, and the specifications of the hydraulic device can be modified as appropriate depending on the functions required of the pile driver. The mounting position takes into consideration the relative positions of other structures and equipment. For example, the controller may be installed inside a house together with the inverter. The specifications and mounting position of the load detection unit are also optional. The generator may be placed on the ground and operated separately from the pile driver. This is advantageous for operation in confined spaces such as buildings and tunnels. The power source is not limited to a generator, and may also be a battery unit or a fuel cell (hydrogen power generation) unit.

[0023] The control program can also be modified as desired, and when limiting the load on the electric motor, the timing can be determined based on the rotational drive state (load state) of the auger, for example. Furthermore, when a shortage of generated power needs to be compensated for, an auxiliary battery can be installed. In addition, when applied to systems for battery-powered construction machinery, which have seen increasing demand in recent years, the electric motor driven by the battery can be the object of control. [Explanation of symbols]

[0024] 11...pile driver, 12...lower running body, 13...upper rotating body, 14...base machine, 15...leader, 16...guide pipe, 17...guide gib, 18...auger, 18a...auger reducer, 19...operator's cab, 20...house, 21...winch device, 22...counterweight, 23...portable diesel generator, 24...frame, 25...gantry, 26...backstay, 27...main hoisting rope, 28...top sheave, 29...jack, 30...controller, 31...inverter, 32...primary cable, 33...secondary cable, 34...cable support, 35...screw rod, 36...casing, 37...electric motor, 38...hydraulic pump, 39...inverter, 40...primary cable, 41...secondary cable

Claims

1. a base machine having an upper rotating body rotatably provided on an upper part of a lower traveling body; a leader provided at the front of the upper rotating body in a manner that allows it to be raised and lowered; an auger that can be raised and lowered along the front surface of the reader; a hydraulic device that serves as a hydraulic source for driving the auger up and down; a power source for rotating the auger; In a pile driver equipped with The hydraulic device is an electric motor that receives power from the power source; a hydraulic pump driven by the electric motor; an inverter for controlling the rotation speed of the electric motor; a controller for controlling the inverter; a motor load detection unit that detects a load amount of the electric motor; an auger load detection unit that detects a load amount against the rotational drive of the auger; and A pile driver characterized in that the controller performs control to limit the load on the electric motor when it determines that the sum of the load detected by the motor load detection unit and the auger load detection unit exceeds the output of the power source.

2. 2. The pile driver according to claim 1, wherein the power source is a diesel generator mounted on the pile driver.

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