JP2016127728A - Work machine drive control system, work machine including the same, and drive control method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive control system capable of improving a regeneration efficiency.SOLUTION: A drive control system 1 includes a hydraulic motor 33, a hydraulic oil supply device 9, an electric motor 34, a capacitor 28, a driving device 36, and a control device 50. The driving device 36 moves the electric motor 34 by supplying power from the capacitor 28 to the electric motor 34 and brakes a revolving superstructure 5 by storing the power generated by the electric motor 34 in the capacitor 28. The control device 50 sets an electric motor target torque of the electric motor 34 and controls an operation of the driving device 36 by supplying driving power to the driving device 36 so that the electric motor 34 generates the electric motor target torque. Also, when determining that a torque stop condition is satisfied, the control device 50 stops the driving power supplied from the capacitor 28 to the driving device 36. The torque stop condition is a condition that the electric motor target torque is nearly zero.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a drive control system in which a hydraulic motor and an electric motor cooperate to drive a structure of a work machine, and energy is regenerated by the electric motor when the structure is braked, and a work machine including the drive control system The present invention relates to a drive control method.

  Work machines such as excavators and cranes are publicly known, and these work machines can perform various operations by moving work equipment such as excavators and cranes. These work machines have a lower body capable of traveling, and an upper revolving body is provided on the upper body so as to be able to turn. A work device is attached to the upper swing body, and the orientation of the work device can be changed by turning the upper swing body. Further, the work machine is provided with a drive control system for turning the upper turning body.

  One example of a drive control system is described in Patent Document 1. The drive control system of Patent Document 1 includes a hydraulic motor and an electric motor. The electric motor and the hydraulic motor cooperate with each other to rotate the upper swing body. The hydraulic motor is driven by pressure oil discharged from a hydraulic pump, and the electric motor is driven by electric power supplied from the power storage device. Moreover, the electric motor has a power generation function, and converts the kinetic energy of the upper turning body during turning into electric power to brake the upper turning. The converted electric power is stored in the power storage device and used when it is next driven.

JP 2012-62653 A

  A system including an electric motor such as the drive control system of Patent Document 1 includes a drive device (for example, an inverter) for driving the electric motor. The drive device has a conversion function such as AC / DC conversion or voltage conversion. By this conversion function, the rotational speed of the motor is increased to accelerate the upper swing body, or the electric motor generates electric power to brake the upper swing body. It has come to be.

  Drive power is supplied from the power storage device to these drive devices and electric motors regardless of whether or not they are driven, and energy is constantly lost. In other words, the drive power (so-called standby power) is supplied to the drive device and the motor even during constant speed turning or stopping by hydraulic drive that does not require the motor to generate torque, and as a result, steady loss occurs. ing. Then, the electric power stored in the power storage device is consumed where it is not related to the turning acceleration of the upper-part turning body, and the overall regeneration efficiency of the drive control system may be reduced.

  Then, this invention aims at providing the drive control system which can improve regeneration efficiency.

  The drive control system for a work machine according to the present invention can discharge and charge a hydraulic motor that operates a structure by receiving a supply of hydraulic fluid, a hydraulic fluid supply device that supplies the hydraulic fluid to the hydraulic motor, and the like. A power storage device and an electric motor that operates the structure of the work machine in cooperation with the hydraulic motor by supplying electric power from the power storage device, and brakes the structure by generating power and regenerating the power storage device. Driving the electric motor by being supplied with driving electric power, setting the electric power supplied to the electric motor and the regenerative electric power to the power storage device, and setting the electric motor target torque of the electric motor, A control device that controls the operation of the drive device by supplying the drive power to the drive device in accordance with the motor target torque, the control device including an electric power that includes the motor target torque being zero. If it is determined that satisfy the stop condition, but adapted to stop the supply of the drive power to the drive device.

  According to the present invention, it is possible to prevent the power of the power storage device from being consumed due to the steady loss of the drive device and the motor during constant speed turning or stopping by hydraulic drive that does not require the motor to generate torque. . Thereby, conventionally, the electric power consumed by the steady loss can be used when the structure is operated next, and the regeneration efficiency of the drive control system can be improved.

  In the above invention, the control device acquires a storage amount of the power storage device, and when the storage amount falls below a predetermined amount, sets the motor target torque to zero and stops the supply of drive power to the drive device. Also good.

  If the said structure is followed, it can prevent that the electric power of an electrical storage apparatus is discharged excessively by the steady loss of a drive device and an electric motor.

In the above invention, a speed detector for detecting an operating speed of the structure is provided,
When the control device determines that the power stop condition including that the structure is decelerated and the operation speed detected by the speed detector is equal to or lower than a predetermined speed is satisfied, the motor target torque is set to zero, The supply of drive power to the drive device may be stopped.

  According to the above configuration, when the operating speed of the structure at the time of deceleration braking becomes a predetermined speed, for example, the steady loss becomes larger than the electric power obtained from the electric motor, Power consumption can be prevented. Thereby, conventionally, the electric power consumed by the steady loss can be used when the structure is operated next, and the regeneration efficiency of the drive control system can be improved.

  A work machine according to the present invention includes the drive control system according to any one of the above and the structure, the structure is a turning body, and the electric motor and the hydraulic motor include a speed reducer. In this way, the revolving body is driven to turn.

  If the said structure is followed, the working machine which has an effect as mentioned above is realizable.

  A drive control method for a drive control system according to the present invention is supplied from an electric motor and a hydraulic fluid supply device that actuate a structure by supplying power from a power storage device, generate power, regenerate the power storage device, and brake the structure. The structure is operated in cooperation with a hydraulic motor that is driven by the hydraulic fluid, and the drive device that is operated by being supplied with the drive power uses the electric motor target torque to supply the electric power supplied by the electric motor and the regenerative electric power of the power storage device. A drive control method for a drive control system that adjusts according to the following: a setting step of setting a motor target torque of the motor, and whether or not a power stop condition including satisfying that the motor target torque is zero is satisfied When it is determined that the power stop condition is satisfied in the first determination step and the first determination step, the power supply from the power storage device to the drive device is stopped before A method and a stopping step of stopping the driving of the driving device.

  According to the present invention, it is possible to prevent the power of the power storage device from being consumed due to the steady loss of the drive device and the motor during constant speed turning or stopping by hydraulic drive that does not require the motor to generate torque. . Thereby, conventionally, the electric power consumed by the steady loss can be used when the structure is operated next, and the regeneration efficiency of the drive control system can be improved.

  In the above invention, a speed detecting step for detecting an operating speed of the structure, and the operating speed detected by the operating speed detector is braked by the electric motor to decelerate the structure and decelerate, and is less than a predetermined speed. A second determination step for determining whether or not a power stop condition including the above is satisfied, and when it is determined that the power stop condition is satisfied in the second determination step, the motor target torque The power supply from the power storage device to the drive device may be stopped to stop driving the drive device.

  If the said structure is followed, the power consumption of the electrical storage apparatus by the steady loss of the drive device and an electric motor at the time of deceleration braking can be prevented. Thereby, conventionally, the electric power consumed by the steady loss can be used when the structure is operated next, and the regeneration efficiency of the drive control system can be improved.

  According to the present invention, regeneration efficiency can be improved.

It is a side view showing a hydraulic excavator provided with a drive control system concerning the 1st and 2nd embodiments of the present invention. FIG. 3 is a hydraulic circuit diagram showing a hydraulic circuit of the drive control system of the first and second embodiments provided in the hydraulic excavator of FIG. 1. FIG. 3 is an electric circuit diagram showing an electric circuit of a drive device provided in the drive control system of FIG. 2. The speed command input from the operation lever provided in the drive control system of FIG. 2, the actual speed of the swing body with respect to the speed command, the output torque of the motor, the assist torque of the hydraulic motor, the output torque of the electro-hydraulic swing motor, and the storage energy over time It is a sequence diagram which shows a change. The speed command input from the operation lever provided in the drive control system of the second embodiment, the speed record of the swing body with respect to the speed command, the output torque of the motor, the assist torque of the hydraulic motor, the output torque of the electro-oil swing motor, and the stored energy It is a sequence diagram which shows a time-dependent change. It is a flowchart which shows the procedure of the deceleration control process which the drive control system of 2nd Embodiment performs.

  Hereinafter, the configuration of the drive control systems 1 and 1A and the hydraulic excavator 2 including the same according to the first and second embodiments of the present invention will be described with reference to the drawings described above. In addition, the concept of the direction in the embodiment is used for convenience of explanation, and regarding the structure of the drive control system 1, 1 </ b> A and the hydraulic excavator 2, the arrangement and direction of those configurations should be limited to that direction. It is not a suggestion. Further, the structure and control of the drive control systems 1 and 1A and the hydraulic excavator 2 described below are only one embodiment of the present invention, and the present invention is not limited to the embodiment and is within the scope of the invention. Can be added, deleted and changed.

[Hydraulic excavator]
As shown in FIG. 1, a hydraulic excavator 2, which is an example of a work machine, can perform various operations such as excavation and transportation with an attachment, for example, a bucket 3, attached to a distal end portion. The excavator 2 includes a traveling device 4 such as a crawler, and a revolving body 5 is placed on the traveling device 4. The revolving structure 5 that is a structural body is provided with a driver's seat 5 a for a driver to board, and is further provided with a bucket 3 via a boom 6 and an arm 7. The revolving structure 5 configured as described above is configured to be able to turn with respect to the traveling device 4. The excavator 2 has a drive control system 1 that drives the swing body 5 to swing. Below, the structure of the drive control system 1 is demonstrated, referring FIG.

[Drive control system]
The drive control system 1 mainly includes a hydraulic pump 10, a control valve 11, a remote control valve 12, two electromagnetic pressure reducing valves 13 and 14, two electromagnetic relief valves 15 and 16, and an electro-hydraulic turning motor 17. It has. The hydraulic pump 10 that is a hydraulic pump is a variable displacement swash plate hydraulic pump, and is driven by an engine (not shown) to discharge hydraulic oil. The hydraulic pump 10 includes a swash plate 10a. The hydraulic oil discharge amount can be changed by tilting the swash plate 10a. A regulator 18 is connected to the swash plate 10a.

The regulator 18 has a servo piston (not shown). The servo piston is connected to a swash plate 10a, and the swash plate 10a is tilted at a tilt angle corresponding to the position of the servo piston. The regulator 18 is connected to the pilot pump 20 via an electromagnetic pressure reducing valve 19, and the servo piston moves to a position corresponding to the command pressure p ₀ discharged from the electromagnetic pressure reducing valve 19. . The electromagnetic pressure reducing valve 19 outputs a command pressure p ₀ that is reduced to a pressure corresponding to the command signal given thereto. Therefore, the swash plate 10 a is tilted to a tilt angle corresponding to the command signal, and hydraulic oil having a flow rate corresponding to the tilt angle is discharged from the discharge port 10 b of the hydraulic pump 10. A control valve 11 is connected to the discharge port 10b through a discharge passage 21.

  The control valve 11 is a spool valve provided with a spool 22, and by moving the spool 22, it is possible to change the flow rate of hydraulic oil flowing to the connection destination and the connection destination of the hydraulic pump 10. Further, two pilot passages 23 and 24 are connected to the control valve 11, and the remote control valve 12 is connected via the pilot passages 23 and 24.

  The remote control valve 12 as an input device is a device for inputting a target turning speed. The input device is not limited to a hydraulic type and may be an electric type. The remote control valve 12 has an operation lever 25, and the operation lever 25 is configured to be tiltable in one direction and the other in a predetermined direction. The remote control valve 12 outputs pilot oil having a pressure corresponding to the tilt amount (adjustment value) of the operation lever 25 to the pilot passages 23 and 24 corresponding to the tilt direction of the operation lever 25. Pilot pressure sensors 26 and 27 are connected to the pilot passages 23 and 24, respectively, and the pilot pressure sensors 26 and 27 detect the hydraulic pressure output from the remote control valve 12.

In addition, electromagnetic pressure reducing valves 13 and 14 are interposed in the pilot passages 23 and 24, respectively. The electromagnetic pressure reducing valves 13 and 14 are so-called normally open pressure reducing valves, and the pressure corresponding to the current (command value) that flows through the electromagnetic pressure reducing valves 13 and 14 by reducing the pressure of the pilot oil output from the remote control valve 12. Configured to adjust to. The pilot oil output from the remote control valve 12 is guided to both ends of the spool 22 by the pilot passages 23 and 24, respectively. The spool 22 receives pilot pressures p ₁ and p ₂ at both ends, and moves to a position corresponding to the pilot pressures p ₁ and p ₂ . The control valve 11 moves the spool 22 so as to change the connection destination of the hydraulic pump 10 and the flow rate of hydraulic fluid flowing to the connection destination.

  The configuration of the control valve 11 will be described in detail. The control valve 11 has four ports 11a to 11d. The first port 11a is connected to the hydraulic pump 10 through the discharge passage 21, and the second port. 11 b is connected to the tank 29 through the tank passage 30. Further, the third port 11c and the fourth port 11d are connected to the electro-hydraulic turning motor 17 through the first oil passage 31 and the second oil passage 32, respectively. The connection destinations of these four ports 11 a to 11 d change depending on the position of the spool 22. That is, when the spool 22 is located at the neutral position M1, the first port 11a and the second port 11b are connected, and the hydraulic pump 10 enters the unload state. When the spool 22 moves to the first offset position A1, the first port 11a and the third port 11c are connected, and the second port 11b and the fourth port 11d are connected. On the other hand, when the spool 22 moves to the second offset position A2, the first port 11a and the fourth port 11d are connected, and the second port 11b and the third port 11c are connected. When the spool 22 is thus positioned at the first or second offset position A1, A2, the hydraulic pump 10 and the electric oil turning motor 17 are connected, and hydraulic oil is supplied to the electric oil turning motor 17.

  The electric oil turning motor 17 includes a hydraulic motor 33, an electric motor 34, and an output shaft 35. The output shaft 35 is connected to the revolving body 5 via a reduction gear (not shown), and the revolving body 5 is revolved by rotating the output shaft 35. The hydraulic motor 33 and the electric motor 34 are integrally formed, and rotate the output shaft 35 in cooperation. Below, the structure of the hydraulic motor 33 and the electric motor 34 is explained in full detail.

  The electric motor 34 is a three-phase AC motor, for example, and has a stator and a rotor (not shown). The rotor is provided on the output shaft 35 so as not to be relatively rotatable, and the stator is provided on the hydraulic motor 33 so as not to be relatively rotatable. The rotor and the stator are configured to be rotatable relative to each other, and a three-phase alternating current (hereinafter also simply referred to as “alternating current”) is passed through the stator coil to rotate according to the frequency of the alternating current. The output shaft 35 is rotated forward or backward at a speed. Further, the electric motor 34 has a power generation function for generating an alternating current by converting rotational energy (kinetic energy) of the output shaft 35 into electric energy, so that the rotating output shaft 35 is decelerated by generating power. It has become. The electric motor 34 configured as described above is electrically connected to the driving device 36 and further electrically connected to the battery 28 via the driving device 36. The battery 28 can store electric power, and is configured to discharge a direct current to the driving device 36.

  As shown in FIG. 3, the drive device 36 has a boost chopper 36a and an inverter 36b. The step-up chopper unit 36 a is connected to the capacitor 28 and has a function of boosting the direct current supplied from the capacitor 28 and stepping down the direct current supplied to the capacitor 28. In addition, an inverter unit 36b is connected to the step-up chopper unit 36a, and a DC current boosted by the step-up chopper unit 36a is guided to the inverter unit 36b.

  The inverter unit 36b is configured by a plurality of switching elements. The inverter unit 36b is supplied with, for example, pulse-width-modulated driving power from a control device 50, which will be described later, and converts the DC current into AC current by switching on and off the switching element in accordance with the driving power to convert the DC current into AC current. 34 is supplied. At this time, the inverter unit 36b adjusts the power supplied to the electric motor 34 in accordance with the pulse width of the driving electric power. Specifically, the inverter 36b changes the frequency of the alternating current supplied to the electric motor 34 so as to apply a desired acceleration torque to the electric motor 34. Can be generated. Further, the inverter unit 36b converts the alternating current generated in the electric motor 34 into a direct current by switching on and off of the switching element according to the driving power. The driving device 36 guides the converted direct current to the battery 28 via the step-up chopper 36a and stores it in the battery 28. At this time, the inverter unit 36b adjusts the regenerative power to the battery 28 in accordance with the pulse width of the drive power. Specifically, the inverter unit 36b changes the frequency of the alternating current generated in the motor 34 to give a desired braking torque to the motor 34. Can be generated (that is, a regenerative operation can be performed).

  Thus, the drive device 36 can switch on and off the switching elements of the step-up chopper unit 36a and the inverter unit 36b to supply electric power to the motor 34 or charge the battery 28. On the other hand, the drive device 36 cuts off the supply of drive power to the boost chopper unit 36a and the inverter unit 36b by completely turning off the function of the switching elements of the boost chopper unit 36a and the inverter unit 36b. Steady loss can be suppressed. Thus, the drive device 36 is switched between a servo-on state in which drive power is supplied and a servo-off state in which supply of drive power is stopped.

  The hydraulic motor 33 is a fixed capacity type hydraulic motor, for example, and has two supply / discharge ports 33a and 33b. The first oil passage 31 is connected to the first supply / discharge port 33a, and the second oil passage 32 is connected to the second supply / discharge port 33b. When hydraulic oil is supplied to the first supply / discharge port 33a, the hydraulic motor 33 causes the torque corresponding to the hydraulic pressure and flow rate of the hydraulic oil to act on the output shaft 35 in the positive direction, and operates on the second supply / discharge port 33b. When oil is supplied, a torque corresponding to the hydraulic pressure and flow rate of the hydraulic oil is applied to the output shaft 35 in the reverse direction. That is, the hydraulic motor 33 assists the rotation of the output shaft 35 by applying an assist torque corresponding to the hydraulic pressure and flow rate of the supplied hydraulic oil to the output shaft 35. The hydraulic oil for driving the hydraulic motor 33 is supplied to the hydraulic motor 33 by the hydraulic oil supply device 9.

  The hydraulic fluid supply device 9 which is a pressure fluid supply device is mainly composed of the hydraulic pump 10 described above, a control valve 11 and two electromagnetic pressure reducing valves 13 and 14, and further has two electromagnetic relief valves 15 and 16. doing. The electromagnetic relief valves 15, 16 are connected to the first oil passage 31 and the second oil passage 32, respectively, and the hydraulic oil in the first oil passage 31 and the second oil passage 32 is supplied to the tank 29 via the electromagnetic relief valves 15, 16. It is arranged so that it can be discharged. The electromagnetic relief valves 15 and 16 arranged in this way have a pressure adjusting function for adjusting the hydraulic pressure of the hydraulic oil discharged to the tank 29 to a pressure corresponding to the current (command value) flowing therethrough. In the hydraulic oil supply device 9, the output shaft 35 is configured such that the hydraulic oil is discharged through the electromagnetic relief valves 15, 16 by blocking between the discharge side oil passages 31, 32 and the tank 29 by the control valve 11. Can be decelerated by braking. The braking force acting on the output shaft 35 can be changed by adjusting the oil pressure of the oil passages 31 and 32 on the discharge side by the electromagnetic relief valves 15 and 16.

  The hydraulic oil supply device 9 includes relief valves 38 and 39 and check valves 40 and 41. The relief valves 38 and 39 and the check valves 40 and 41 include the first oil passage 31 and the second oil. Each is connected to a path 32. The relief valves 38 and 39 open the oil passages 31 and 32 to the tank 29 when the hydraulic oil flowing through the oil passages 31 and 32 exceeds a set pressure. Damage is suppressed. The check valves 40 and 41 are connected to the tank 29, permitting the flow of hydraulic oil from the tank 29 to the oil passages 31 and 32, and blocking the flow of hydraulic oil in the reverse direction. . As a result, hydraulic oil that is insufficient when driving the hydraulic motor 33 can be guided from the tank 29 to the hydraulic motor 33 via the check valves 40 and 41.

Furthermore, the first oil passage 31 and the second oil passage 32 are provided with hydraulic pressure sensors 42 and 43, respectively, and the hydraulic pressure supplied to the supply / discharge ports 33a and 33b of the hydraulic motor 33 is the hydraulic pressure sensors 42 and 43, respectively. Has been detected by. Further, the electric oil turning motor 17 is provided with a rotation speed sensor 44 on the output shaft 35, and the rotation speed sensor 44 as a speed detector is connected to the rotation speed of the output shaft 35 (that is, the rotation speed of the output shaft 35). ) Is detected. These sensors 42 to 44 and the pilot pressure sensors 26 and 27 described above are electrically connected to a control device 50 that controls various components, and transmit detected values to the control device 50. Specifically, the hydraulic pressure detected by the hydraulic pressure sensors 42 and 43 is input to the control device 50, and the differential pressure between them is the differential pressure feedback signal DP. Further, the pilot pressure detected by the pilot pressure sensors 26 and 27 is input to the control device 50, and the differential pressure between them is the speed command signal _VCOM . Further, the rotational speed detected by the rotational speed sensor 44 is input to the control device 50 and becomes a speed feedback signal _VFB .

  The control device 50 is electrically connected to the battery 28 and detects the amount of power stored in the battery 28 based on the power output from the battery 28. In addition, the control device 50 is supplied with power from the battery 28 and is operated by the supplied power. Further, the control device 50 is electrically connected to a plurality of components as will be described later, and supplies power (signal) to each connected component to drive each component.

  More specifically, the control device 50 is electrically connected to the electromagnetic pressure reducing valves 13 and 14, the electromagnetic relief valves 15 and 16, the electromagnetic pressure reducing valve 19, and the driving device 36, and further each sensor 26, 27, 42-. 44 is also connected. The control device 50 controls the operation of the valves 13 to 16 and 19 according to the detection results of the sensors 26, 27 and 42 to 44, and generates a desired assist torque (acceleration torque or braking torque) to the hydraulic motor 33. It is supposed to let you. The control device 50 supplies drive power to the drive device 36 (specifically, the inverter unit 36b), and controls the operation of the drive device 36 by adjusting the supplied drive power so as to obtain a desired power. An acceleration torque or a braking torque is generated in the electric motor 34. As described above, the control device 50 controls the operations of the hydraulic motor 33 and the electric motor 34 to rotate the revolving structure 5 with desired operations (rotation direction, speed and torque).

  Further, the control device 50 controls the operations of the valves 13 to 16 and 19 and the drive device 36 so that the hydraulic motor 33 and the electric motor 34 function as a brake, and the revolving body 5 that makes a turn can be braked. It has become. Further, the control device 50 can stop the supply of drive power to the drive device 36 and switch the drive device 36 to the servo-off state. Hereinafter, the control operation of the control device 50 will be described with reference to the sequence diagram of FIG.

[Control operation of control device]
The control device 50 starts the drive control process when the excavator 2 is powered on. The control device 50 first calculates the target total torque based on the speed difference between the speed command signal V _COM and the speed feedback signal V _FB, and then generates the target total torque from the motor 34 based on the amount of power stored in the capacitor 28. The torque to be generated is set as the motor target torque (acceleration torque or braking torque).

  When the amount of electricity stored in the battery 28 decreases to a predetermined amount or less, the control device 50 sets the electric motor target torque for driving the swing body 5 to zero. Here, the predetermined amount is an amount of electricity that cannot be efficiently driven by the battery 28. In this way, the motor target torque is set.

  When the power stop condition including that the set motor target torque is zero is satisfied, the control device 50 stops supplying the drive power to the drive device 36 and switches the state of the drive device 36 to the servo-off state. (Or keep). That the motor target torque is zero includes that the motor target torque is zero or a value in the vicinity thereof. This eliminates the steady loss that occurs in the drive unit 36 and the motor 34 during acceleration, constant speed turning, and stopping, which does not require torque generation in the motor, and the capacitor is stored during acceleration, constant speed turning, and stopping. 28 can prevent power consumption. In addition, when the amount of electricity stored in the battery 28 becomes equal to or less than a predetermined amount, the electric motor target torque is set to zero, and in this case also, the supply of drive power to the drive device 36 is stopped. Thereby, it is possible to prevent the electric power of the battery 28 from being excessively discharged due to the steady loss of the driving device 36 and the electric motor 34.

  On the other hand, when the power stop condition including that the set motor target torque is zero is not satisfied, the control device 50 switches (or maintains) the state of the drive device 36 to the servo-on state, and the motor 34 is set to the motor target. The operation of the drive device 36 is controlled so as to generate torque. For example, when the operation lever 25 is operated to one side or the other as shown in FIG. 4, the control device 50 gives drive power to the drive device 36 to accelerate the revolving body 5, and accelerates torque (motor target) from the motor 34. Torque) is output, and the revolving structure 5 is accelerated to a desired speed. Further, as shown in FIG. 4, when the operation lever 25 is returned to the neutral position, drive power is supplied to the drive device 36 to brake the revolving structure 5 to cause the electric motor 34 to generate electric power, and braking torque (motor target torque). ) And the revolving unit 5 is braked to a desired speed.

  That is, the control device 50 applies drive power corresponding to the motor target torque to the drive device 36 to adjust the supply power of the motor 34 or the regenerative power from the motor 34, and causes the motor 34 to accelerate or brake the revolving structure 5.

  In the drive control system 1 that performs such drive control, it is possible to prevent the power consumption of the battery 28 due to the steady loss of the drive device 36 and the motor 34 when the revolving structure 5 is turning at a constant speed, at the time of stopping, and at the time of low power storage. it can. As a result, conventionally, the electric power consumed by the steady loss (refer to the dotted line portion in the stored energy in FIG. 4) and the electric power required to turn the revolving body 5 next (see the shaded portion in the stored energy in FIG. 4). Can be used as Therefore, the regeneration efficiency of the drive control system 1 can be further improved.

[About the second embodiment]
The drive control system 1A of the second embodiment has the same configuration as that of the drive control system 1 of the first embodiment, but executes a deceleration control process as shown below in addition to the drive control process described above. It is like that. Below, the point of the deceleration control process which is a different point from the drive control system 1 of 1st Embodiment in the drive control system 1A of 2nd Embodiment is demonstrated, referring FIG.5 and FIG.6. In addition, regarding the configuration of the drive control system 1A of the second embodiment, the same components as those of the drive control system 1 of the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In the drive control system 1A of the second embodiment, as shown in FIG. 5, when the operation lever 25 is tilted to one side, pilot oil is output to only one of the two pilot passages 23 and 24. Then, it is detected by one of the two pilot pressure sensors 26, 27, the detected pilot pressure is input to the control device 50, and the differential pressure between them is the speed command signal _VCOM . Similarly, the rotational speed detected by the rotational speed sensor 44 is input to the control device 50 and becomes a speed feedback signal _VFB . The control device 50 calculates a target acceleration torque based on the speed difference between the two speed command signals _VCOM and the speed feedback signal _VFB . And the control apparatus 50 controls operation | movement of the hydraulic motor 33 and the electric motor 34 so that this target acceleration torque may be output. Thereby, the revolving structure 5 can be turned at a speed according to the tilting amount of the operation lever 25, that is, at a speed according to the speed command signal _VCOM .

Thereafter, when the operation lever 25 moves to the neutral position, the pilot pressure on the high pressure side decreases, the spool 22 of the control valve 11 moves to the neutral position M1, and the opening of the control valve 11 becomes smaller. On the other hand, the hydraulic pressure detected by the two pilot pressure sensors 26 and 27 also decreases. Then, control device 50 determines that the deceleration control should be performed based on the speed difference between speed command signal V _COM and speed feedback signal V _FB, and starts the deceleration control. Then, the deceleration control process starts and the process proceeds to step S1 in FIG. The flowchart in FIG. 6 is for the case where the servo is turned off when the discharge power due to the steady loss of the drive device 36 is larger than the charge power due to the regenerative operation of the motor 34 during deceleration by the motor 34.

  In step S1, which is a regenerative braking process, the control device 50 causes the electric motor 34 to perform a regenerative operation to decelerate the output shaft 35. That is, the control device 50 controls the operation of the drive device 36 (the operation of the switching element) to convert all of the alternating current generated by the electric motor 34 into a direct current so that all the electric power generated by the electric motor 34 is stored in the battery 28. The output shaft 35 is decelerated. Further, in order to efficiently perform the energy regeneration in the electric motor 34, the control device 50 gives an instruction to the electromagnetic relief valves 15 and 16 connected to the oil passages 31 and 32 on the discharge side to open the hydraulic motor 33. Adjust the braking force by. When the output shaft 35 decelerates, the process proceeds to step S2.

  In step S2, which is a power stop condition determination step, the control device 50 determines whether or not the power stop condition is satisfied. Here, the power stop condition is a condition that the speed of the revolving structure 5 is equal to or lower than a predetermined speed (that is, the absolute value of the speed of the revolving structure 5 is equal to or lower than a predetermined speed) regardless of the forward direction and the reverse direction. The predetermined speed is a speed at which the steady loss energy consumed by the electric motor 34 and the driving device 36 when braking the revolving structure 5 is larger than the charging power generated by the electric motor 34. It is set according to the structure and various configurations connected to them. The control device 50 determines whether or not the speed of the swing body 5 is equal to or lower than a predetermined speed based on the rotation speed detected by the rotation speed sensor 44, and determines that the speed of the swing body 5 exceeds the predetermined speed. Returning to step S1, the regenerative operation by the electric motor 34 is continued. On the other hand, if it determines with the speed of the revolving body 5 being below a predetermined speed, it will transfer to step S3.

  In step S <b> 3, which is a hydraulic braking process, the control device 50 controls the operation of the hydraulic oil supply device 9 and operates the swing body 5 by the hydraulic motor 33. More specifically, the control device 50 gives a command to the electromagnetic relief valves 15 and 16 on the discharge side to reduce the opening thereof (increase the set pressure of the electromagnetic relief valve), and increase the brake pressure of the hydraulic motor 33. Make it high. Thereby, a braking force can be applied to the output shaft 35, and the revolving structure 5 can be braked even after the drive device 36 is stopped. When braking by the hydraulic motor 33 starts, the process proceeds to step S4.

  In step S4, which is a servo-off process, the control device 50 stops the supply of drive power to the drive device 36. More specifically, the control device 50 transmits a servo-off command to the drive device 36, and switches the switching element in the drive device 36 to OFF so that the drive device 36 and the capacitor 28 are disconnected from each other, thereby driving the drive device 36. Stop. As a result, the steady loss that occurs in the drive device 36 and the motor 34 can be eliminated at the time of braking that does not require the motor to generate torque. It is possible to prevent power consumption. When the drive device 36 and the battery 28 are disconnected, the process proceeds to step S5.

  In step S5, which is a turning body stopping step, it is determined whether the speed of the turning body 5 is substantially zero (below the speed at which the turning body 5 can be determined to have stopped) regardless of the forward direction and the reverse direction. The control device 50 determines whether or not the speed of the swing body 5 is substantially zero based on the rotation speed detected by the rotation speed sensor 44, and determines that the speed of the swing body 5 is approximately zero. The deceleration control of the body 5 ends.

  The drive control system 1 that performs such deceleration control stops the supply of drive power to the drive device 36 when the speed of the revolving structure 5 becomes a predetermined speed or less, and therefore the drive device 36 and the motor 34 during deceleration braking. It is possible to prevent the power consumption of the battery 28 due to the steady loss. As a result, conventionally, the power consumed by the steady loss (see the dotted line portion in the stored energy in FIG. 4) is the power required to turn the revolving body 5 next (see the shaded portion in the stored energy in FIG. 5). Can be used as Therefore, the regeneration efficiency of the drive control system 1 can be further improved.

[Other embodiments]
The drive control system 1 of the present embodiment is a system that adjusts the tilt angle of the swash plate 10a by a positive control method, but may be a system that adjusts the tilt angle of the swash plate 10a by a negative control method. The hydraulic pump 10 may be a fixed displacement pump that cannot adjust the inclination angle of the swash plate 10a.

  Further, in the drive control system 1 of the present embodiment, the electro-hydraulic turning motor 17 in which the hydraulic motor 33 and the electric motor 34 are integrally formed is used, but the hydraulic motor 33 and the electric motor 34 are configured separately. May be. The motor 34 is not necessarily limited to a three-phase AC motor, and may be a DC motor. The work machine to which the drive control system 1 is applied is not limited to the hydraulic excavator 2 described above, and may be applied to a hydraulic crane or the like. Moreover, although the hydraulic fluid used with the drive control system 1 of this embodiment is oil, it is not limited to oil, What is necessary is just a liquid. Further, in the drive control system 1 of the present embodiment, the electro-hydraulic turning motor 17 in which the hydraulic motor 33 and the electric motor 34 are integrally formed is used. However, the electric oil turning motor 17 may be configured only by the electric motor 34.

DESCRIPTION OF SYMBOLS 1,1A Drive control system 2 Hydraulic excavator 5 Rotating body 9 Hydraulic oil supply device 17 Electric oil slewing motor 28 Electric storage device (electric storage device)
33 Hydraulic motor 34 Electric motor 35 Output shaft 36 Drive device 44 Rotational speed sensor 50 Control device

Claims (7)

A hydraulic motor that operates the structure by receiving a pressurized fluid supply; and
A hydraulic fluid supply device for supplying hydraulic fluid to the hydraulic motor;
A power storage device capable of discharging and charging;
An electric motor that operates the structure in cooperation with the hydraulic motor by supplying power from the power storage device, and brakes the structure by generating power and regenerating the power storage device;
A driving device that operates by being supplied with driving power to drive the electric motor, and adjusts the electric power supplied to the electric motor and the regenerative electric power to the power storage device;
A control device configured to set an electric motor target torque of the electric motor, supply driving power to the driving device according to the electric motor target torque, and control an operation of the driving device;
When the control device determines that the power stop condition including that the electric motor target torque is zero is satisfied, the drive control system for the work machine is configured to stop supplying the drive power to the drive device.   The control device acquires the amount of electricity stored in the electricity storage device, and when the amount of electricity stored is less than or equal to a predetermined amount, sets the motor target torque to zero and stops supplying drive power to the drive device. Item 2. A work machine drive control system according to Item 1. A speed detector for detecting the operating speed of the structure;
When the control device determines that the power stop condition including that the structure is decelerated and the operation speed detected by the speed detector is equal to or lower than a predetermined speed is satisfied, the motor target torque is set to zero, The drive control system for a work machine according to claim 1 or 2, wherein supply of drive power to the drive device is stopped. The drive control system according to any one of claims 1 to 3,
Comprising the structure,
The structure is a swivel body,
The electric motor and the hydraulic motor are work machines configured to drive the swivel body through a speed reducer. An electric motor that operates and generates power by supplying power from the power storage device, regenerates the power storage device and brakes the structure, and a hydraulic motor that is driven by the hydraulic fluid supplied from the hydraulic fluid supply device cooperate with each other. A drive control system for a work machine in which a drive device that operates by operating the structure and being supplied with drive power adjusts the supply power of the motor and the regenerative power of the power storage device according to the motor target torque Drive control method,
A setting step of setting a motor target torque of the motor;
A first determination step for determining whether or not an electric power stop condition including that the electric motor target torque is zero;
A drive control of the work machine having a stop step of stopping the drive of the drive device by stopping the power supply from the power storage device to the drive device when it is determined in the first determination step that the power stop condition is satisfied System drive control method.   In the first determination step, the amount of electricity stored in the electricity storage device is acquired, and when the amount of electricity stored is less than or equal to a predetermined amount, the electric motor target torque is set to zero, and supply of drive power to the drive device is stopped. A drive control method for a drive control system for a work machine according to claim 5. A speed detecting step for detecting an operating speed of the structure;
A second determination for determining whether or not a power stop condition is satisfied, wherein the structure is braked and decelerated by the electric motor and the operating speed detected in the speed detection step is equal to or lower than a predetermined speed. A process,
When it is determined that the power stop condition is satisfied in the second determination step, the stop step sets the motor target torque to zero, stops the power supply from the power storage device to the drive device, and drives the drive device The drive control method of the drive control system of the work machine according to claim 5 or 6, wherein the control is stopped.