JP2006097427A - Revolvable controlling device of construction machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a revolvable controlling device of a construction machine capable of preventing the reverse rotation by insufficient torque just as a mechanical brake is released in the case revolving start of an upper revolving body. <P>SOLUTION: A controlling means calculating motor torque against load torque by detecting the load torque acting on the upper revolving body 13 includes an invertor 21 supplying electric power to a motor 14 by controlling a controller 30, switches 23a and 23b short-circuiting/open-circuiting each input terminal of the motor 14 and current detectors 24U, 24V and 24W detecting an input current of the motor 14. The controller 30 controls to produce the motor torque against the load torque in the motor 14 before the mechanical brake 22 is released. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a turning control device for a construction machine, and more particularly, to a turning control device for a construction machine including an electric motor that drives a turning of an upper turning body and a mechanical brake that holds a stop position of the upper turning body. .

  2. Description of the Related Art Conventionally, in a swing construction machine such as an excavator or a crane, a hydraulic motor swing drive system using a hydraulic motor that is rotated by oil discharged from a hydraulic pump as a swing drive source of an upper swing body is generally widely known. In this hydraulic motor turning drive system, the operating direction, speed, and the like of the hydraulic motor are changed by controlling the direction and flow rate of the pressure oil by a control valve provided between the hydraulic pump and the hydraulic motor. However, this method has a problem in that the amount of hydraulic energy cut off by the control valve is large and energy loss is large.

  On the other hand, an electric motor turning drive system using an electric motor as a turning drive source of the upper-part turning body is known (for example, see Patent Document 1). In this electric motor turning drive system, the turning direction and speed of the upper turning body are controlled by changing the rotation direction and speed of the electric motor, and energy efficiency can be greatly improved as compared with the hydraulic motor drive system.

  Here, as the turning means for the upper turning body, in the case of the hydraulic motor turning drive system described above, the control valve shuts off the oil passage at the neutral position of the operation lever, stops the rotation of the hydraulic motor, and applies the braking force. generate.

On the other hand, in the case of the electric motor turning drive system, the energization to the electric motor is cut off at the neutral position of the operation lever, and neither the driving force nor the braking force acts on the electric motor, so that only the inertia works. For this reason, there is provided a turning control device that includes a mechanical brake for holding the upper turning body at the turning stop position when turning is stopped and that releases the mechanical brake after holding the electric motor at a speed of 0 by servo lock control when turning is started. It is known (see, for example, Patent Document 2).
JP 2000-289983 A Japanese Patent Laid-Open No. 2001-10783

  In the case of the conventional electric motor turning drive system, the mechanical brake is operated in the neutral position of the operation lever to hold the upper turning body at the turning stop position.For example, when the construction machine turns toward the upward inclination on the slope, With the mechanical brake activated, the motor is held at speed 0 by servo lock control, and the mechanical brake is released to start turning. However, when the mechanical brake is released, the upper swinging body reverses due to insufficient motor torque. There is a risk that it will rotate.

  Therefore, a technical problem to be solved arises in order to prevent reverse rotation due to insufficient torque immediately after the mechanical brake is released when the upper swinging body is turned on, and the present invention solves this problem. The purpose is to do.

  The present invention has been proposed in order to achieve the above object, and the invention according to claim 1 includes an electric motor that drives the upper swing body to swing and a mechanical brake that holds a stop position of the upper swing body. In the construction machine, there is provided control means for detecting a load torque acting on the upper swing body and calculating an electric motor torque against the load torque, and before releasing the mechanical brake, an electric motor torque against the load torque is provided. A turning control device for a construction machine configured to be generated by the electric motor is provided.

  According to this configuration, the control means detects the load torque that acts on the upper swing body in advance, and calculates the motor torque that opposes the detected load torque. And at the time of turning start of the upper swing body, the control means controls the motor to generate a motor torque that opposes the calculated load torque before releasing the mechanical brake.

  According to a second aspect of the present invention, the control means controls the motor by using a permanent magnet synchronous motor as the motor, a switch for short-circuiting / opening the input terminal of the motor, a current detector for detecting the input current of the motor, and the motor. Provided is a turning control device for a construction machine, which includes an inverter for controlling the inverter and a controller for controlling the inverter.

  According to this structure, the said control means can short-circuit the input terminal of an electric motor with a switch, can generate | occur | produce brake torque with the induced voltage by rotation of an electric motor, and can counter load torque. Further, the torque at this time can be calculated based on the detection value of the current detector.

  The invention according to claim 3 provides a turning control device for a construction machine, wherein the control means is configured to calculate a load torque from an input current of the motor when the input terminal of the motor is short-circuited to release the mechanical brake. To do.

  According to this configuration, the input terminal of the motor is short-circuited by the switch, the brake torque is generated by the induced voltage due to the rotation of the motor, and the load torque is counteracted. The detected value of the current detector at this time acts on the upper swing body. The load torque to be calculated can be calculated.

  The invention according to claim 1 is provided with a control means for detecting a load torque acting on the upper swing body and calculating an electric motor torque against the load torque, and resists the load torque before releasing the mechanical brake. Since the motor torque is generated in the motor, the control means detects the load torque acting on the upper swing body in advance, calculates the motor torque against this load torque, and starts the swing of the upper swing body. When the mechanical brake is released, it is possible to prevent the motor from rotating reversely due to insufficient torque even when the mechanical brake is released by generating the motor torque against the calculated load torque in the electric motor. .

  According to a second aspect of the present invention, the control means uses a permanent magnet synchronous motor as the motor, a switch for short-circuiting / opening the input terminal of the motor, a current detector for detecting the input current of the motor, and an inverter for controlling the motor And a controller for controlling the inverter, in addition to the effect of the invention of claim 1, when the input terminal of the motor is short-circuited by a switch and the controller releases the mechanical brake, The controller can calculate the motor torque, that is, the load torque acting on the upper swing body, from the input current of the motor detected by the detector.

  The invention according to claim 3 is configured such that the control means calculates the load torque from the input current of the electric motor when the input terminal of the electric motor is short-circuited to release the mechanical brake. In addition to the effects of the invention, it is possible to estimate the load applied to the upper swing body, generate torque against the load when the mechanical brake is released, and prevent the upper swing body from rotating backward.

  Hereinafter, a turning control device for a construction machine according to the present invention will be described with reference to preferred embodiments. The purpose of preventing reverse rotation due to insufficient torque at the start of turning of the upper swing body is to detect the load torque acting on the upper swing body and counteract the load torque. This is realized by providing a control means for calculating the motor torque and generating the motor torque against the load torque before releasing the mechanical brake.

  FIG. 1 shows a hydraulic excavator 10 as an example of a construction machine, and an upper swing body 13 is mounted on a lower traveling body 11 via a swing mechanism 12 so as to be rotatable. The turning mechanism 12 includes a turning electric motor 14 provided in the upper turning body 13, a speed reducer 15 that decelerates the rotation of the electric motor 14, a ring gear 16 fixed to the lower traveling body 11, and meshing with the ring gear 16. The pinion gear (not shown) is rotated by the electric motor 14 and the like.

  A cab 17 is provided on one front side of the upper swing body 13, and a boom 18 is attached to the front center portion so as to be able to be raised and lowered. Further, an arm 19 is attached to the tip of the boom 18 so as to be rotatable up and down, and a bucket 20 is attached to the tip of the arm 19.

  FIG. 2 is a block diagram of the turning control device according to the present invention. In this embodiment, a permanent magnet synchronous motor (PM motor) is used as the electric motor 14 that drives the upper turning body 13 to turn. Permanent magnet synchronous motors have the advantage that they can be mounted on a vehicle such as a construction machine because they are driven by an inverter to obtain a highly efficient drive amount and are small and light. The electric motor 14 is supplied with electric power from a generator or a battery (both not shown) via an inverter 21 which is a part of the control means.

  In addition, switches 23 a and 23 b are provided between the motor 14 and the inverter 21 to short-circuit and open each input terminal of the motor 14 under the control of the controller 30. Further, current detectors 24U, 24V, and 24W for detecting the input current of the electric motor 14 are provided. The U-phase current, the V-phase current, and the W-phase current are detected, and the detected current is input to the inverter 21.

  The aforementioned control means includes the inverter 21, switches 23a and 23b, current detectors 24U, 24V and 24W, and a controller 30.

  The electric motor 14 is provided with a mechanical brake 22 that generates a mechanical braking force. When the electric motor 14 is energized with the mechanical brake 22 released under the control of the controller 30, the electric motor 14 rotates and the rotational force is increased. Is transmitted to the upper swing body 13 via a speed reducer (shown in FIG. 1), and the upper swing body 13 rotates left or right.

  Further, a turning operation lever 25 is provided as a turning operation means, and for example, a potentiometer or the like is incorporated. If the operation lever 25 is operated to the left or right, a command signal corresponding to the operation amount is input to the controller 30.

  Next, a control procedure in the turning control device according to the present invention will be described. The control means detects a load torque acting on the upper swing body 13 in advance, and calculates an electric motor torque against the detected load torque. In order to detect the load torque, for example, under the control of the controller 30, the switches 23a and 23b are turned on to short-circuit the input terminal of the motor 14, and the mechanical brake 22 is released. At this time, the current detectors 24U, The input current of the motor 14 is detected at 24V and 24W. The detected U-phase current, V-phase current, and W-phase current are input to the inverter 21, and the controller 30 calculates the motor torque, that is, the load torque acting on the upper swing body 13 from the detected current.

  Thus, since the load torque is calculated from the input current of the electric motor 14 when the mechanical brake 22 is released, the load applied to the upper swing body 13 can be estimated, and the electric motor torque against this load is calculated as the electric motor 14. It is possible to prevent reverse rotation due to insufficient torque.

  Thus, when the excavator 10 turns, for example, uphill on an inclined ground, the controller 30 releases the mechanical brake 22 before starting the turning of the upper turning body 13 with the operation lever 25. Then, the inverter 21 is controlled so as to generate a motor torque that opposes the calculated load torque. Therefore, when the mechanical brake 22 is released, the electric motor 14 is driven by the electric torque that opposes the load torque, and thus the reverse rotation of the upper swing body 13 can be prevented.

  It should be noted that 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.

1 is a side view of a hydraulic excavator to which the present invention is applied. The block diagram of the turning control apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Hydraulic excavator 12 Turning mechanism 13 Upper turning body 14 Electric motor 21 Inverter 22 Mechanical brake 23a, 23b Switch 24U, 24V, 24W Current detector 30 Controller

Claims (3)

In a construction machine comprising an electric motor that drives the upper swing body to rotate and a mechanical brake that holds the stop position of the upper swing body,
Control means for detecting a load torque acting on the upper swing body and calculating an electric motor torque against the load torque is provided, and before the mechanical brake is released, an electric motor torque against the load torque is generated in the electric motor. A swing control device for a construction machine, wherein The control means is a permanent magnet synchronous motor, and the switch for short-circuiting / opening the input terminal of the motor, a current detector for detecting the input current of the motor, an inverter for controlling the motor, and controlling the inverter The turning control device for a construction machine according to claim 1, further comprising a controller. The turning control device for a construction machine according to claim 1 or 2, wherein the control means is configured to calculate a load torque from an input current of the electric motor when the input terminal of the electric motor is short-circuited to release the mechanical brake.

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