JP7021862B2 - Motor drive system - Google Patents

Description

The present invention relates to a motor drive system.

Devices and machines such as injection molding machines and servo presses are equipped with a motor drive system. Motor drive systems will also be installed in construction machinery such as hybrid excavators and forklifts, and work vehicles.

FIG. 1 is a basic block diagram of a motor drive system 100R. The motor drive system 100R includes a motor (motor) 102, a rotation sensor 104, and a motor driver 110. The rotation sensor 104 detects the state of the motor 102. The motor driver 110 feedback-controls the motor 102 based on the state of the motor 102 detected by the rotation sensor 104.

The motor driver 110 includes a communication circuit 112, a motor control processing unit 114, and a motor drive circuit 116. The communication circuit 112 and the rotation sensor 104 are connected via a cable 140 so that communication is possible. Specifically, the communication circuit 112 transmits the request signal RQ to the rotation sensor 104. In response to the request signal RQ from the communication circuit 112, the rotation sensor 104 transmits the state of the motor 102, for example, the speed data Dv indicating the rotation speed (or the position data indicating the position of the rotor) to the communication circuit 112.

The motor control processing unit 114 executes the motor control processing and generates a drive command REF based on the speed information received by the communication circuit 112. The content of the motor control process varies depending on the application and the place of use of the motor drive system 100R. The motor drive circuit 116 includes an inverter and drives the motor 102 based on the drive command REF.

Japanese Unexamined Patent Publication No. 2011-192015

In a motor drive system, from the viewpoint of safety and reliability of the device, a function (referred to as a runaway detection function) for determining an overspeed state when the rotation speed of the motor exceeds a predetermined threshold value may be required. When designing a new motor drive system, a runaway detection function may be implemented in the motor control processing unit 114, but it is not so easy when it is desired to add a runaway detection function to the existing motor drive system 100. The present inventors have considered adding a runaway detection function to the motor drive system 100R of FIG. 1 which does not have a runaway detection function.

FIG. 2 is a block diagram of the motor drive system 100S according to the comparative technique examined by the present inventors. The motor drive system 100S has a runaway detection function, and when the runaway of the motor 102 is detected, the power supply to the motor 102 is stopped.

In addition to the motor drive system 100R of FIG. 1, the motor drive system 100S includes a second rotation sensor 106, a safety controller 120, and an electromagnetic contactor 108. The rotation sensor 106 is added for the purpose of runaway detection. The safety controller 120 detects a runaway state based on the state (rotational speed) of the motor 102 detected by the rotation sensor 106. When the runaway state is detected, the magnetic contactor 108 is shut off and the driving of the motor 102 is stopped. For example, the safety controller 120 includes a communication circuit 122 and a runaway detection processing unit 124. The communication circuit 122 and the rotation sensor 106 are connected via a cable 141 so that communication is possible. The communication circuit 122 transmits the request signal RQ ₂ to the rotation sensor 106. The rotation sensor 106 transmits speed data Dv ₂ indicating the rotation speed of the motor 102 to the communication circuit 122 in response to the request signal RQ ₂ from the communication circuit 122. The runaway detection processing unit 124 determines whether or not the rotation speed of the motor 102 exceeds a predetermined value based on the speed information received by the communication circuit 122. When the runaway detection processing unit 124 determines that the runaway state is determined, the magnetic contactor 108 is shut off.

In the motor drive system 100S of FIG. 2, a rotation sensor 106 for runaway detection is required in addition to the rotation sensor 104, and the safety controller 120 requires a communication circuit 122 capable of communicating with the rotation sensor 106, and further rotates. It is necessary to route the cable 141 connecting the sensor 106 and the communication circuit 122. As described above, if an attempt is made to add a runaway detection function to the motor drive system 100R of FIG. 1, the cost and size increase.

The present invention has been made in view of the above problems, and one of the exemplary objects of the embodiment is to provide a motor drive system capable of detecting an abnormality.

One aspect of the invention relates to a motor drive system. The motor drive system is connected to the motor driver that controls the drive of the motor via a communication line, detects the state of the motor, and transmits communication data including information indicating the state of the motor to the motor driver. It comprises a rotation sensor that is connected to a communication line and a safety controller that includes an interception circuit that intercepts communication data transmitted from the rotation sensor to the motor driver.
According to this aspect, the abnormality can be detected inexpensively with a small number of additional parts.

The safety controller can generate a detection value indicating at least one of the rotation speed, position, and acceleration of the motor based on the communication data intercepted by the interception circuit, and detects a runaway state in which the detection value deviates from a predetermined range. An abnormality detection unit may be further included. This makes it possible to provide a runaway detection function with a small number of additional parts. Runaway conditions can include overspeed, overposition, and overacceleration.

When the runaway detection processing unit detects the runaway state, it may output a cutoff signal instructing the cutoff of the power supply to the motor.

The safety controller may be able to detect a communication failure between the rotation sensor and the motor driver based on the communication data intercepted by the interception circuit.

When the safety controller detects a communication failure, it may output a cutoff signal instructing the cutoff of the power supply to the motor.

Another aspect of the invention relates to an injection molding machine. The injection molding machine may be equipped with any of the motor drive systems described above. Yet another aspect of the invention relates to construction machinery. The construction machine may be equipped with any of the motor drive systems described above.

It should be noted that any combination of the above components or components or expressions of the present invention that are mutually replaced between methods, devices, systems, etc. are also effective as aspects of the present invention.

According to the present invention, an abnormality can be detected by an inexpensive system.

It is a basic block diagram of a motor drive system. It is a block diagram of the motor drive system which concerns on the comparative technique examined by the present inventors. It is a block diagram of the motor drive system which concerns on 1st Embodiment. It is a block diagram of the motor drive system which concerns on 2nd Embodiment. It is a block diagram of the motor drive system which concerns on 3rd Embodiment. It is a figure which shows the injection molding machine which concerns on embodiment. It is a block diagram which shows the electric system of an injection molding machine. It is a perspective view which shows the appearance of the excavator which is an example of the construction machine which concerns on embodiment. It is a block diagram of the electric system and the hydraulic system of the excavator which concerns on embodiment.

Hereinafter, the present invention will be described with reference to the drawings based on the preferred embodiments. The same or equivalent components, members, and processes shown in the drawings shall be designated by the same reference numerals, and duplicate description thereof will be omitted as appropriate. Further, the embodiment is not limited to the invention, but is an example, and all the features and combinations thereof described in the embodiment are not necessarily essential to the invention.

(First Example)
FIG. 3 is a block diagram of the motor drive system 100A according to the first embodiment. The motor drive system 100A includes an electromagnetic contactor 108 and a safety controller 130 in addition to the motor drive system 100R of FIG.

The rotation sensor 104 is connected to the motor driver 110 via a cable 140. The cable 140 includes communication lines 142 and 144. The communication circuit 112 of the motor driver 110 transmits the request signal RQ to the rotation sensor 104 via the communication line 144. The rotation sensor 104 detects the state of the motor 102. In response to the request signal RQ, the rotation sensor 104 transmits the communication data Dc including the detected information indicating the state of the motor 102 to the motor driver 110 via the communication line 142. For example, the rotation sensor 104 may be a speed detector that detects the rotation speed of the motor 102, and in this case, the communication data Dc includes information indicating the rotation speed of the motor 102. The rotation sensor 104 may be an encoder that detects the position of the rotor of the motor 102, and in this case, the communication data Dc may include the position information of the rotor of the motor 102. Alternatively, the communication data Dc may include acceleration information indicating the acceleration of the motor 102.

The communication circuit 112 receives the communication data Dc. The motor control processing unit 114 generates a drive command REF based on the information included in the communication data Dc received by the communication circuit 112. The content of the motor control process varies depending on the application and the place of use of the motor drive system 100A. For example, the motor control processing unit 114 may perform position control, speed control, or pressure control. The motor drive circuit 116 includes an inverter and drives the motor 102 based on the drive command REF.

The safety controller 130 includes an interception circuit 132 and an abnormality detection unit 134. The interception circuit 132 is connected to the communication line 142 and intercepts the communication data Dc transmitted from the rotation sensor 104 to the motor driver 110. The interception circuit 132 is a block added to the existing communication system including the communication circuit 112 and the rotation sensor 104, so that the interception circuit 132 does not communicate with the communication circuit 112 or the rotation sensor 104. Communication is only performed between the communication circuit 112 and the rotation sensor 104, and they are not aware of the interception circuit 132. On the other hand, the interception circuit 132 knows the communication protocol of the rotation sensor 104 and the communication circuit 112, and can peep at the information contained in the communication data Dc.

In this embodiment, the abnormality detection unit 134 has two functions, that is, a runaway detection function and a communication abnormality detection function. The abnormality detection unit 134 can generate a detection value (speed information) according to the rotation speed of the motor 102 based on the intercepted communication data Dc. Velocity information can be obtained from the value when the communication data Dc indicates the speed of the motor 102, from the differential value when indicating the position, and from the integrated value when indicating the acceleration. In connection with the runaway detection function, the abnormality detection unit 134 determines that the runaway state is obtained when the rotation speed indicated by the speed information deviates from a predetermined range. More specifically, it is determined whether the rotation speed is higher or lower than the threshold value, and when the rotation speed of the motor 102 exceeds the threshold value, it is determined that the vehicle is in a runaway state of overspeed. When the abnormality detection unit 134 detects the runaway state, it generates a cutoff signal SD instructing the cutoff of the power supply to the motor 102. The electromagnetic contactor 108 is provided between the output of the motor drive circuit 116 and the motor 102, and is in a cutoff state when the cutoff signal SD is input.

Further, the abnormality detection unit 134 can detect a communication failure between the rotation sensor 104 and the motor driver 110 based on the communication data Dc intercepted by the interception circuit 132 in relation to the communication abnormality detection function. The method for detecting a communication failure is not particularly limited, but is expected from, for example, (i) the signal level of the communication line 142 does not fluctuate over a predetermined time, and (ii) the communication frame transmitted from the rotation sensor 104 to the communication circuit 112. Examples include the case where the preamble is not included, (iii) when the communication data is encoded in an error detection and correctable manner, and the error correction occurs continuously more than a predetermined number of times. When the abnormality detection unit 134 detects a communication failure, it outputs a cutoff signal SD to the magnetic contactor 108 to cut off the power supply to the motor 102.

The above is the configuration of the motor drive system 100A.
According to the motor drive system 100A, a runaway of the motor 102 can be detected and an emergency stop can be performed. Further, since the communication abnormality between the rotation sensor 104 and the motor driver 110 can be detected, the motor 102 can be urgently stopped when the motor driver 110 loses control of the motor 102 due to the communication abnormality. As described above, the motor drive system 100A is superior to the motor drive system 100R of FIG. 1 in terms of safety and reliability.

Further, the motor drive system 100A has the following advantages as compared with the motor drive system 100S of FIG.
First, the motor drive system 100A has the advantage that it requires less additional hardware than the motor drive system 100S. Specifically, the motor drive system 100S of FIG. 2 requires two rotation sensors 104 and 106, whereas the motor drive system 100A of FIG. 3 requires only one rotation sensor. Since the rotation sensor is expensive, the motor drive system 100A of FIG. 3 can improve safety and reliability at a lower cost than the motor drive system 100S of FIG. In addition, the motor drive system 100A of FIG. 3 does not require the additional cable 141 required for the motor drive system 100S of FIG. 2, so that cost and space can be saved.

Secondly, the communication circuit 122 in the motor drive system 100S of FIG. 2 needs a function of communicating with the rotation sensor 106, specifically, a function of transmitting a request signal RQ and receiving speed data Dv. The function was needed. On the other hand, since the interception circuit 132 of the motor drive system 100A of FIG. 3 does not need the function of transmitting the request signal RS, the hardware configuration of the interception circuit 132 should be simplified as compared with the communication circuit 122. Can be done.

(Second Example)
FIG. 4 is a block diagram of the motor drive system 100B according to the second embodiment. The motor drive system 100B includes an emergency stop switch 150 in addition to the motor drive system 100A of FIG. The safety controller 130 is connected to the emergency stop switch 150, and when the emergency stop switch 150 is pressed and the emergency stop signal STOP is input, the shutdown signal SD is output to the electromagnetic contactor 108. The OR circuit 136 outputs a shutdown signal SD when at least one of the stop trigger and the emergency stop signal STOP generated by the abnormality detection unit 134 indicates a stop.

(Third Example)
FIG. 5 is a block diagram of the motor drive system 100C according to the third embodiment. In this motor drive system 100C, an STO (safety torque off) circuit 118 is provided in the motor driver 110 instead of the magnetic contactor 108. When the abnormality detection unit 134 detects an abnormality, it outputs a cutoff signal (STO signal). When the STO circuit 118 receives the STO signal, the drive command REF input to the motor drive circuit 116 is changed so that the torque of the motor 102 is reduced.

The present invention has been described above based on the embodiments. It is understood by those skilled in the art that this embodiment is an example, and that various modifications are possible for each of these components and combinations of each processing process, and that such modifications are also within the scope of the present invention. be. Hereinafter, such a modification will be described.

(Modification 1)
In the embodiment, the abnormality detection unit 134 has decided to detect a runaway state related to overspeed, but this is not the case. The abnormality detection unit 134 may be able to generate a detection value (position information) according to the position of the rotor of the motor 102 based on the intercepted communication data Dc. Position information can be obtained from the integrated value when the communication data Dc indicates the speed of the motor 102, from the integrated value when indicating the position, and from the double integrated value when indicating the acceleration. In connection with the runaway detection function, the abnormality detection unit 134 may determine that the runaway state is obtained when the value of the position information deviates from a predetermined range. This makes it possible to detect a runaway state in which the position is exceeded. Of course, the lack of position may be included in the runaway state.

Alternatively, the abnormality detection unit 134 may be able to generate a detection value (acceleration information) according to the acceleration of the rotor of the motor 102 based on the intercepted communication data Dc. Acceleration information can be obtained from the differential value when the communication data Dc indicates the speed of the motor 102, from the derivative value twice when the position is indicated, and from the value when the acceleration is indicated. In connection with the runaway detection function, the abnormality detection unit 134 may determine that the runaway state is obtained when the value of the acceleration information deviates from a predetermined range. This makes it possible to detect a runaway state of excessive acceleration (or insufficient acceleration).

(Modification 2)
In the embodiment, the case where the abnormality detection unit 134 performs both the runaway detection and the communication abnormality detection has been described, but the present invention is not limited to this. The abnormality detection unit 134 may only detect runaway or may only detect communication abnormalities. Furthermore, the types of abnormalities detected by the safety controller 130 are not limited to runaway detection and communication abnormality detection, and other abnormalities (for example, failure or abnormality of the rotation sensor 104) may be detected.

(Modification 3)
In the embodiment, it is assumed that the runaway detection function is not implemented in the existing motor drive system, but this is not the case. For example, when the runaway detection function is implemented in the motor control processing unit 114, the safety controller 130 with the runaway detection function may be added to duplicate the runaway detection. Alternatively, in the existing motor drive system, when the runaway detection function is already mounted on the motor control processing unit 114, the safety controller 130 with communication abnormality detection may be added.

(Modification example 4)
In the embodiment, when an abnormality is detected, a cutoff signal is output to the magnetic contactor 108 or the STO circuit 118 to stop the motor 102, but the method of stopping the motor 102 is not limited. For example, the safety controller 130 may output an alert signal to a controller higher than the motor driver 110, and the higher controller may stop the motor drive system 100. The motor drive system 100 may be provided with a mechanical brake (not shown), or the mechanical brake may be operated according to the output of the cutoff signal.

(Modification 5)
As described above, this technology is effective when adding a safety function to an existing motor drive system, but it is also effective when designing and developing a new motor drive system.

(Use)
Subsequently, the use of the motor drive system 100 will be described. The motor drive system 100 can be suitably used for an injection molding machine.

(Application 1. Injection molding machine)
FIG. 6 is a diagram showing an injection molding machine 600 according to an embodiment. The injection molding machine 600 mainly includes an injection device 611, a mold clamping device 612, and an ejector device 671. These are supported on the base frame 613. Further, a removable mold device 643 is attached to the injection device 611.

The mold device 643 includes a fixed mold 644 and a movable mold 645 and is attached to the mold clamping device 612. The injection device 611 heats and melts the resin and pours it into the internal space of the mold device 643 (injection). The mold clamping device 612 fastens the fixed mold 644 and the movable mold 645, applies pressure to the resin inside, cools the mold, and forms the resin into a shape corresponding to the mold. The ejector device 671 takes out the molded resin from the mold device 643.

A specific configuration of the injection molding machine 600 will be described.
(Injection device)
The injection device 611 is supported by the injection device frame 614. The guide 681 is arranged in the longitudinal direction of the injection device frame 614. Then, the ball screw shaft 621 is rotatably supported by the injection device frame 614, and one end of the ball screw shaft 621 is connected to the plasticized moving motor 622. Further, the ball screw shaft 621 and the ball screw nut 623 are screwed together, and the ball screw nut 623 and the injection device 611 are connected via the spring 624 and the bracket 625. Therefore, when the plasticization transfer motor 622 is driven in the forward direction or the reverse direction, the rotational motion of the plasticization transfer motor 622 is a combination of the ball screw shaft 621 and the ball screw nut 623, that is, a linear motion by the screw device 691. And this linear motion is transmitted to the bracket 625. Then, the bracket 625 is moved in the direction of arrow A along the guide 681, and the injection device 611 is moved forward and backward.

Further, a heating cylinder 615 is fixed to the bracket 625 toward the front (left side in the figure), and an injection nozzle 616 is arranged at the front end (left end in the figure) of the heating cylinder 615. A hopper 617 is arranged in the heating cylinder 615, and a screw 626 is arranged inside the heating cylinder 615 so as to be able to move forward and backward (move in the left-right direction in the figure) and rotatably, and after the screw 626. The end (right end in the figure) is supported by the support member 682.

A servomotor for driving a weighing device (hereinafter abbreviated as a servomotor for weighing) 683 is attached to the support member 682, and rotation generated by driving the servomotor 683 for weighing is transmitted via a timing belt 684. It is designed to be transmitted to the screw 626.

The ball screw shaft 685 is rotatably supported in the injection device frame 614 in parallel with the screw 626, and the ball screw shaft 685 and the injection device drive servomotor (hereinafter abbreviated as injection servomotor) 686 are provided. It is connected via a timing belt 687. Then, the front end of the ball screw shaft 685 is screwed with the ball screw nut 674 fixed to the support member 682. Therefore, when the injection servomotor 686 is driven, the rotational motion is converted into a linear motion by the combination of the ball screw shaft 685 and the ball screw nut 674, that is, the screw device 692, and the linear motion is transmitted to the support member 682. To.

Next, the operation of the injection device 611 will be described. First, in the weighing process, the weighing servomotor 683 is driven, the screw 626 is rotated via the timing belt 684, the injection servomotor 686 is driven, and the screw 626 is moved to a predetermined position via the timing belt 687. Move backward (move to the right in the figure). At this time, the resin supplied from the hopper 617 is heated and melted in the heating cylinder 615, and is stored in front of the screw 626 as the screw 626 retracts.

Next, in the injection process, the injection nozzle 616 is pressed against the fixed mold 644, the injection servomotor 686 is driven, and the ball screw shaft 685 is rotated via the timing belt 687. At this time, the support member 682 is moved along with the rotation of the ball screw shaft 685 to move the screw 626 forward (move to the left in the figure), so that the resin accumulated in front of the screw 626 is ejected from the injection nozzle 616. Then, the cavity space 647 formed between the fixed mold 644 and the movable mold 645 is filled.

(Molding device)
Next, the mold clamping device 612 will be described. The mold clamping device 612 is supported by the base frame 613 so as to face the injection device 611. The mold clamping device 612 is arranged to face the fixed platen 651, the toggle support 652, the tie bar 653 erected between the fixed platen 651 and the toggle support 652, and the fixed platen 651, and can freely move forward and backward along the tie bar 653. It comprises an disposed movable platen 654 and a toggle mechanism 656 disposed between the movable platen 654 and the toggle support 652. Then, the fixed mold 644 and the movable mold 645 are attached to the fixed platen 651 and the movable platen 654 so as to face each other.

The toggle mechanism 656 advances and retreats the movable platen 654 along the tie bar 653 by advancing and retreating the crosshead 658 between the toggle support 652 and the movable platen 654 by a clamping servomotor (not shown) to move the movable mold 645. The mold is closed, compacted, and opened by being brought into contact with and separated from the fixed mold 644.

Therefore, the toggle mechanism 656 swings with respect to the toggle lever 661 swingably supported with respect to the crosshead 658, the toggle lever 662 swingably supported with respect to the toggle support 652, and the movable platen 654. It consists of a freely supported toggle arm 663, and is linked between the toggle lever 661 and the toggle lever 662, and between the toggle lever 662 and the toggle arm 663, respectively.

Further, the ball screw shaft 664 is rotatably supported by the toggle support 652, and the ball screw shaft 664 and the ball screw nut 665 fixed to the cross head 658 are screwed together. Then, in order to rotate the ball screw shaft 664, a mold clamping servomotor (not shown) is attached to the side surface of the toggle support 652.

Therefore, when the mold clamping servomotor is driven, the rotational movement of the mold clamping servomotor is converted into a linear motion by the combination of the ball screw shaft 664 and the ball screw nut 665, that is, the screw device 693, and the linear motion is crossed. It is transmitted to the head 658, and the cross head 658 is moved back and forth in the direction of the arrow C. That is, when the crosshead 658 is advanced (moved to the right in the figure), the toggle mechanism 656 is extended to advance the movable platen 654, mold closing and mold clamping are performed, and the crosshead 658 is retracted (in the figure). When it is moved to the left), the toggle mechanism 656 is bent, the movable platen 654 is retracted, and the mold is opened.

FIG. 7 is a block diagram showing an electric system of the injection molding machine 600. The commutator 702 is connected to an AC power supply and rectifies the AC to generate a DC voltage. The converter 704 stabilizes the DC voltage from the rectifier 702 to a predetermined voltage level and generates a _DC link voltage VDC in the DC link bus 708. A smoothing capacitor 706 for stabilizing the _DC link voltage VDC is connected to the DC link bus 708. A plurality of inverters 720 are connected to the DC link bus 708. Each inverter 720 drives a corresponding motor 722. The motors 722A to 722C may be the above-mentioned plasticized moving motor 622, weighing servo motor 683, injection servo motor 686, and mold clamping servo motor. In addition, the injection molding machine 600 is provided with various servo mechanisms, and an inverter 720 and a motor 722 are provided on each axis.

The bidirectional converter 710 is provided between the DC link bus 708 and the power storage module 712. The power storage module 712 mainly functions as a backup power source, and when the AC power supply is cut off, the bidirectional converter 710 supplies the power of the power storage module 712 to the smoothing capacitor 706 instead of the converter 704. Further, when the inverter 720 performs the regenerative operation and the surplus energy is generated, the bidirectional converter 710 charges the power storage module 712 with the surplus energy. There is also an injection molding machine 600 that does not include the bidirectional converter 710 and the power storage module 712.

The motor drive system 100 according to the embodiment can be adopted for a motor drive system of any axis such as a mold clamping servo motor, a plasticized moving motor, a weighing servo motor, and an injection servo motor. Specifically, the combination of the inverter 720 and the motor 722 in FIG. 7 corresponds to the motor drive system 100.

Another use of the motor drive system 100 is construction machinery.
(Use 2. Excavator)
FIG. 8 is a perspective view showing the appearance of the excavator 500, which is an example of the construction machine according to the embodiment. The excavator 500 mainly includes a lower traveling body (crawler) 502 and an upper swivel body 504 rotatably mounted on the upper part of the lower traveling body 502 via a swivel mechanism 503.

An attachment 510 is attached to the swivel body 504. The attachment 510 includes a boom 512, an arm 514 linked to the tip of the boom 512, and a bucket 516 linked to the tip of the arm 514. The boom 512, arm 514, and bucket 516 are hydraulically driven by the boom cylinder 520, arm cylinder 522, and bucket cylinder 524, respectively. Further, the swivel body 504 is provided with a power source such as a driver's cab 508 for accommodating an operator and an engine 506 for generating hydraulic pressure.

FIG. 9 is a block diagram of an electric system, a hydraulic system, and the like of the shovel 500 according to the embodiment. In FIG. 9, the system for mechanically transmitting power is shown by a double line, the hydraulic system is shown by a thick solid line, the flight control system is shown by a broken line, and the electric system is shown by a thin solid line.

The rotating shafts of the engine 506 and the motor generator 530 are both connected to the input shaft of the speed reducer 532 and connected to each other. When the load of the engine 506 is large, the motor generator 530 assists the driving force of the engine 506 by its own driving force, and the driving force of the motor generator 530 passes through the output shaft of the reducer 532 to the main pump 534. Be transmitted. On the other hand, when the load of the engine 506 is small, the driving force of the engine 506 is transmitted to the motor generator 530 via the speed reducer 532, so that the motor generator 530 generates power.

The motor generator 530 is connected to the secondary side (output) end of the assist inverter 531. The assist inverter 531 controls the operation of the motor generator 530 based on a command from the controller 540 (assist inverter controller). Switching between driving the motor generator 530 and power generation is performed by the controller 540 that controls the drive of the electric system in the excavator 500 according to the load of the engine 506 and the like.

A main pump 534 and a pilot pump 536 are connected to the output shaft of the speed reducer 532, and a control valve 544 is connected to the main pump 534 via a high pressure hydraulic line 542. The control valve 544 is a device that controls the hydraulic system in the excavator 500. In addition to the hydraulic motors 550A and 550B for driving the lower traveling body 502 shown in FIG. 8, the boom cylinder 520, the arm cylinder 522 and the bucket cylinder 524 are connected to the control valve 544 via a high pressure hydraulic line. , The control valve 544 controls the hydraulic pressure supplied to them according to the operation input of the driver.

An operating means 554 is connected to the pilot pump 536 via a pilot line 552. The operating means 554 is a lever or pedal for operating the turning electric motor 560, the lower traveling body 502, the boom 512, the arm 514 and the bucket 516, and is operated by the operator.

A control valve 544 is connected to the operating means 554 via the hydraulic line 556, and a pressure sensor 559 is connected via the hydraulic line 558. The operating means 554 converts the hydraulic pressure supplied through the pilot line 552 (hydraulic pressure on the primary side) into hydraulic pressure (hydraulic pressure on the secondary side) according to the operation amount of the operator and outputs the hydraulic pressure. The hydraulic pressure on the secondary side output from the operating means 554 is supplied to the control valve 544 through the hydraulic line 556 and is detected by the pressure sensor 559.

When an operation for turning the turning mechanism 503 is input to the operating means 554, the pressure sensor 559 detects this operation amount as a change in hydraulic pressure in the hydraulic line 558. The pressure sensor 559 outputs an electric signal indicating the oil pressure in the oil pressure line 558. This electric signal is input to the controller 540 as a turning command and is used for driving control of the turning electric motor 560.

The controller 540 (turning inverter controller) receives a rotation speed command according to the operation input, and sets the turning inverter 561 so that the turning speed of the turning electric motor 560 detected by the resolver 562 matches the rotation speed command. Control. For example, the turning motor 560 is AC-driven by the turning inverter 561 by a PWM (Pulse Width Modulation) control command.

The controller 540 is composed of a CPU (Central Processing Unit) and an arithmetic processing unit including an internal memory, and is realized by the CPU executing a drive control program stored in the internal memory. The controller 540 receives operation inputs from various sensors, operation means 554, etc., and performs drive control of the assist inverter 531, the turning inverter 561, the power storage means 570, and the like.

The swivel motor 560 is an AC motor provided in the swivel mechanism 503 of FIG. 8 to rotate the upper swivel body 504. A resolver 562, a mechanical brake 563, and a turning speed reducer 564 are connected to the rotating shaft 566 of the turning electric motor 560.

When the turning electric motor 560 performs power running operation, the rotational force of the rotational driving force of the turning electric motor 560 is amplified by the turning speed reducer 564, and the turning body 504 is controlled by acceleration / deceleration to perform rotational movement. Further, due to the inertial rotation of the swivel body 504, the rotation speed is increased by the swivel speed reducer 564 and transmitted to the swivel motor 560 to generate regenerative power.

The resolver 562 is mechanically connected to the swivel motor 560 and detects the rotation position and the rotation angle of the rotation shaft 566 of the swivel motor 560. The mechanical brake 563 is a braking device that generates a mechanical braking force, and mechanically stops the rotating shaft 566 of the turning electric motor 560 by a command from the controller 540. The swivel reducer 564 decelerates the rotational speed of the rotary shaft 566 of the swivel motor 560 and mechanically transmits it to the swivel mechanism 503.

The power storage means 570 is a power source for the turning inverter 561 and supplies a DC link voltage. The power storage means 570 includes a power storage means, and is configured to be able to store the regenerative energy from the assist inverter 531 and the turning inverter 561 when performing the regenerative operation.

The motor drive system 100 according to the embodiment can be suitably used for the drive system of the turning motor 560.

In addition, the motor drive system 100 can be used to drive a press machine, a crane, an electric forklift, and an electric motor of an AGV (automated guided vehicle).

100 ... motor drive system, 102 ... motor, 104, 106 ... rotation sensor, 108 ... electromagnetic contactor, 110 ... motor driver, 112 ... communication circuit, 114 ... motor control processing unit, 116 ... motor drive circuit, 118 ... STO circuit , 130 ... Safety controller, 132 ... Interception circuit, 134 ... Abnormality detector, 136 ... OR circuit, 500 ... Excavator, 502 ... Lower traveling body, 503 ... Swivel mechanism, 504 ... Swivel body, 506 ... Engine, 508 ... Driver's cab 5,510 ... Attachment, 512 ... Boom, 514 ... Arm, 516 ... Bucket, 520 ... Boom Cylinder, 522 ... Arm Cylinder, 524 ... Bucket Cylinder, 530 ... Motor Motor, 513 ... Assist Inverter, 532 ... Reducer, 534 ... main pump, 536 ... pilot pump, 540 ... controller, 542 ... high pressure hydraulic line, 544 ... control valve, 550A, 550B ... hydraulic motor, 552 ... pilot line, 554 ... operating means, 556 ... hydraulic line, 560 ... for turning Motor, 561 ... Swivel inverter, 562 ... Resolver, 563 ... Mechanical brake, 564 ... Swivel speed reducer, 566 ... Rotating shaft, 558 ... Hydraulic line, 559 ... Pressure sensor, 570 ... Power storage means, 600 ... Injection molding machine, 611 ... Injection device, 612 ... Mold clamping device, 613 ... Main frame, 614 ... Injection device frame, 615 ... Heating cylinder, 616 ... Injection nozzle, 617 ... Hopper, 621 ... Ball screw shaft, 622 ... Plasticization transfer motor, 623 ... ball screw nut, 624 ... spring, 625 ... bracket, 626 ... screw, 643 ... mold device, 644 ... fixed mold, 645 ... movable mold, 647 ... cavity space, 651 ... fixed platen, 652 ... toggle support, 653 ... Tie bar, 654 ... Movable platen, 656 ... Toggle mechanism, 658 ... Cross head, 661, 662 ... Toggle lever, 663 ... Toggle arm, 664 ... Ball screw shaft, 665 ... Ball screw nut, 671 ... Ejector device, 674 ... Ball screw nut, 681 ... Guide, 682 ... Support member, 683 ... Weighing servo motor, 684 ... Timing belt, 685 ... Ball screw shaft, 686 ... Injection servo motor, 687 ... Timing belt, 691, 692, 693 ... Screw Device.

Claims (6)

A motor driver that controls the drive of the motor,
It is connected to the motor driver via a communication line, can communicate with the motor driver according to a predetermined protocol, detects the state of the motor, and communicates with information indicating the state of the motor. A rotation sensor that sends data to the motor driver in response to a request from the motor driver,
A safety controller that is connected to the communication line and includes an interception circuit that intercepts the communication data transmitted from the rotation sensor to the motor driver, and detects an abnormality based on the intercepted communication data.
Equipped with
The motor driver includes a communication circuit having a function of transmitting the request signal and a function of receiving the communication data.
The motor drive system is characterized in that the interception circuit does not have a function of transmitting the request signal, and the hardware configuration of the interception circuit is simplified as compared with the communication circuit . The safety controller can generate a detection value indicating at least one of the rotation speed, the position, and the acceleration of the motor based on the communication data intercepted by the interception circuit, and the detection value deviates from a predetermined range. The motor drive system according to claim 1, further comprising an abnormality detection unit for detecting a runaway state. The motor drive system according to claim 2, wherein the abnormality detection unit outputs a cutoff signal instructing the cutoff of power supply to the motor when the runaway state is detected. The invention according to any one of claims 1 to 3, wherein the safety controller can detect a communication failure between the rotation sensor and the motor driver based on the communication data intercepted by the interception circuit. Motor drive system. The motor drive system according to claim 4, wherein the safety controller outputs a cutoff signal instructing to cut off the power supply to the motor when the communication failure is detected. The motor drive system according to any one of claims 1 to 5, wherein the safety controller is added to an existing system including the motor driver and the rotation sensor.

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