Crusher

Abstract

To facilitate both work efficiency and safety by preventing sudden stoppage due to overload in a crusher.SOLUTION: The crusher includes first and second inverter devices and a biaxial control device. When a second torque moving average value is less than a second torque limit value and an overload warning signal does not indicate execution of overload protection control, a second drive motor is driven in a rotation direction corresponding to a first torque moving average value and at a rotational speed slower than that of a first drive motor corresponding to the first torque moving average value. When the second torque moving average value is equal to or greater than the second torque limit value, the second drive motor is driven in a reverse direction. When the second torque moving average value is less than the second torque limit value and the overload warning signal indicates execution of the overload protection control, the second drive motor is driven in the reverse direction.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This specification discloses a technique related to a crusher. [Background technology]

[0002] A known type of shredder is a twin-shaft shredder, which has two rotating shafts arranged parallel to each other and each with a shredding blade on its outer periphery, and shreds waste sent between the shredding blades by rotating the two rotating shafts.

[0003] Patent Documents 1 and 2 disclose a biaxial crusher that uses an inverter-controlled three-phase induction drive motor to drive the rotating shaft. The biaxial crusher of Patent Document 1 detects the output torque of the drive motor with a sensor and performs crushing while feedback-controlling the drive motor using the sensor detection value. The biaxial crusher of Patent Document 2 detects the rotation speed of the drive motor with a sensor and performs crushing while feedback-controlling the drive motor using the sensor detection value.

[0004] Furthermore, sensorless vector control is generally known as one method for controlling a three-phase induction drive motor (see, for example, Patent Document 3). Sensorless vector control estimates the output torque and rotation speed of the drive motor based on the current and voltage values ​​supplied to the drive motor, and feedback controls the drive motor using these estimated values. This makes it possible for sensorless vector control to control the drive motor without requiring feedback based on sensor-detected values ​​of the output torque and rotation speed of the drive motor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-346420 [Patent Document 2] Japanese Patent Application Laid-Open No. 2005-152877 [Patent Document 3] Patent No. 4543720 Summary of the Invention [Problem to be solved by the invention]

[0006] In twin-shaft crushers, sufficient consideration has not been given to controlling the drive motor using sensorless vector control. In particular, with twin-shaft crushers, it is important to prevent overload on the rotating shaft before it suddenly stops (locks) due to overload. Sudden stopping of the rotating shaft can cause damage to various parts of the crusher, including the crushing blades, as well as a decrease in work efficiency due to the interruption of the crushing process. [Means for solving the problem]

[0007] The technology disclosed in this specification can be realized in the following forms.

[0008] One embodiment disclosed herein is a shredder comprising a first rotating shaft having a first shredding blade disposed on its outer periphery and a second rotating shaft disposed parallel to the first rotating shaft and having a second shredding blade disposed on its outer periphery, wherein the shredder shreds waste material fed between the first shredding blade and the second shredding blade by rotating the first rotating shaft and the second rotating shaft in a forward direction. The shredder also comprises a two-axis control device that controls the operation of the first rotating shaft and the second rotating shaft, a first drive motor that drives the first rotating shaft, a first inverter device that controls the rotation of the first drive motor by first sensorless vector control based on instructions from the two-axis control device, a second drive motor that drives the second rotating shaft, and a second inverter device that controls the rotation of the second drive motor by second sensorless vector control based on instructions from the two-axis control device. The first inverter device outputs a first estimated output torque value estimated as the output torque of the first drive motor in the first sensorless vector control to the two-axis control device; determines whether the first drive motor is in an overload state; executes overload protection control to protect the first drive motor from overload when it determines that the first drive motor is in an overload state; and outputs an overload warning signal indicating the execution of the overload protection control to the two-axis control device when the overload protection control is executed. The second inverter device outputs a second estimated output torque value estimated as the output torque of the second drive motor in the second sensorless vector control to the two-axis control device.The two-axis control device calculates a first torque moving average value which is a moving average value of the first estimated output torque value input from the first inverter device; calculates a second torque moving average value which is a moving average value of the second estimated output torque value input from the second inverter device; instructs the first inverter device to drive the first drive motor in a forward rotation direction at a first rotation speed when the first torque moving average value is less than a first torque limit value; instructs the first inverter device to drive the first drive motor in a reverse rotation direction when the first torque moving average value is equal to or greater than the first torque limit value; and instructs the first inverter device to drive the first drive motor in a reverse direction when the second torque moving average value is less than the second torque limit value. and if the overload warning signal does not indicate that the overload protection control should be performed, instruct the second inverter device to drive the second drive motor in a rotation direction corresponding to the first torque moving average value and at a rotation speed slower than the first rotation speed corresponding to the first torque moving average value; if the second torque moving average value is equal to or greater than the second torque limit value, instruct the second inverter device to drive the second drive motor in a reverse direction; if the second torque moving average value is less than the second torque limit value and the overload warning signal indicates that the overload protection control should be performed, instruct the second inverter device to drive the second drive motor in a reverse direction. According to this embodiment of the crusher, overload of the first rotating shaft, which cannot be completely avoided by controlling the second drive motor based on the rotation direction and rotation speed according to the first torque moving average value, can be avoided by controlling the second drive motor based on the overload warning signal from the first inverter device. As a result, sudden stops due to overload of the first rotating shaft can be prevented, making it easy to achieve both work efficiency and safety factor.

[0009] The technology disclosed in this specification can be realized in various forms other than a crusher, for example, in the form of a control device and a control method for a crusher. [Brief explanation of the drawings]

[0010] [Figure 1]FIG. 2 is an explanatory diagram showing the configuration of a crusher. [Figure 2] FIG. 2 is an explanatory diagram showing the internal configuration of a processing vessel of the crusher. [Figure 3] 10 is a flowchart showing a two-axis control process executed by a processor of the two-axis control device. [Figure 4] 10 is a flowchart showing a high-speed axis control process executed by a processor of the two-axis control device. [Figure 5] 10 is a flowchart showing a slow axis control process executed by a processor of the two-axis control device. DETAILED DESCRIPTION OF THE INVENTION

[0011] FIG. 1 is an explanatory diagram showing the configuration of a shredder 10. The shredder 10 is a biaxial shredder that shreds waste. The shredder 10 includes a treatment vessel 110, a rotating shaft 210, a rotating shaft 220, a biaxial control device 300, an inverter device 410, an inverter device 420, a drive motor 510, a drive motor 520, a reducer 610, and a reducer 620. The explanatory diagram in FIG. 1 includes a plan view of the treatment vessel 110 seen from above.

[0012] Fig. 2 is an explanatory diagram showing the internal configuration of the processing vessel 110 of the crusher 10. The explanatory diagram of Fig. 2 includes a cross-sectional view of the processing vessel 110 taken along the cross-section F2-F2 of Fig. 1. The cross-section F2-F2 is a plane that is perpendicular to the two rotation shafts 210 and 220 and is also perpendicular to the horizontal plane.

[0013] The rotating shaft 210 of the crusher 10 is rotatably provided inside the processing vessel 110. The rotating shaft 210 is an axis extending parallel to a horizontal plane. A plurality of crushing blades 212 and spacers 214 are provided alternately on the outer periphery of the rotating shaft 210.

[0014] The rotating shaft 220 of the crusher 10 is rotatably provided inside the processing vessel 110. The rotating shaft 220 is an axis that extends parallel to a horizontal plane. The rotating shaft 220 is arranged parallel to the rotating shaft 210. The rotating shaft 220 is arranged on the same horizontal plane as the rotating shaft 210. A plurality of crushing blades 222 and spacers 224 are provided alternately on the outer periphery of the rotating shaft 220. The crushing blades 222 of the rotating shaft 220 are provided at positions facing the spacers 214 of the rotating shaft 210. The spacers 214 of the rotating shaft 220 are provided at positions facing the crushing blades 212 of the rotating shaft 210.

[0015] The processing vessel 110 of the shredder 10 is a vessel configured so that the process of crushing waste 810 can be carried out inside. Two rotating shafts 210, 220 are provided inside the processing vessel 110. The processing vessel 110 has an inlet 112 and an outlet 118. The inlet 112 of the processing vessel 110 receives the waste 810 that is introduced from above the processing vessel 110 into the processing vessel 110. The outlet 118 of the processing vessel 110 discharges crushed pieces 820, which are the waste 810 crushed inside the processing vessel 110, below the processing vessel 110.

[0016] The shredder 10 shreds waste 810 sent from above between the shredder blades 212 and 222 by rotating the rotary shafts 210 and 220 in the forward rotation direction FR. The shredder 10 is configured so that the rotary shaft 210 can also rotate in the reverse direction RR, which is the opposite direction to the forward rotation direction FR. The shredder 10 is configured so that the rotary shaft 220 can also rotate in the reverse direction RR, which is the opposite direction to the forward rotation direction FR.

[0017] The inverter device 410 of the crusher 10 controls the drive motor 510 based on instructions from the two-axis control device 300. The inverter device 410 includes a processor 412, a memory 414, a converter circuit 415, an inverter circuit 416, a voltage sensor 417, a current sensor 418, and various interfaces. The processor 412 executes program instructions stored in the memory 414 to perform various processes for controlling the drive motor 510. The converter circuit 415 rectifies AC power supplied from a commercial power source into DC power. Based on instructions from the processor 412, the inverter circuit 416 converts the DC power rectified by the converter circuit 415 into three-phase AC power supplied to the drive motor 510 using pulse width modulation (PWM). The voltage sensor 417 detects a DC voltage CV1 output from the converter circuit 415 and an output voltage MV1 output to the drive motor 510. The current sensor 418 detects the output current MI 1 output to the drive motor 510 .

[0018] The inverter device 410 controls the drive motor 510 by sensorless vector control by referring to the output current MI1 and output voltage MV1 output from the inverter device 410 to the drive motor 510. The inverter device 410 outputs an estimated output torque value TE1 estimated as the output torque of the drive motor 510 in the sensorless vector control to the two-axis control device 300. In this embodiment, the inverter device 410 smoothes the value calculated as the output torque of the drive motor 510 in the sensorless vector control using a low-pass filter to remove noise, and outputs the value to the two-axis control device 300 as the estimated output torque value TE1.

[0019] When the inverter device 410 determines that the drive motor 510 is in an overload state, it executes overload protection control to protect the drive motor 510 from an overload. When the estimated output torque value TE1 exceeds a torque limit value (for example, 210% of the rated torque of the drive motor 510), the inverter device 410 determines that the drive motor 510 is in an overload state. In this case, the inverter device 410 controls the drive motor 510 as overload protection control so that torque exceeding the torque limit value is not generated. Furthermore, when the regenerative energy of the drive motor 510 becomes excessive during deceleration of the drive motor 510 and the DC voltage CV1 output from the converter circuit 415 exceeds a voltage limit value (for example, 190% (380 V) of the power supply voltage (200 V)), the inverter device 410 determines that the drive motor 510 is in an overload state. In this case, the inverter device 410 stops decreasing the frequency of the output power to the drive motor 510 as overload protection control.

[0020] While the inverter device 410 is executing overload protection control for the drive motor 510, it outputs an overload warning signal A1, which indicates the execution of overload protection control, to the two-axis control device 300. In this embodiment, the overload warning signal A1 indicates a value of "0" when overload protection control is not being executed, and indicates a value of "1" when overload protection control is being executed.

[0021] The inverter device 420 of the crusher 10 controls the drive motor 520 based on instructions from the two-axis control device 300. The inverter device 420 includes a processor 422, a memory 424, a converter circuit 425, an inverter circuit 426, a voltage sensor 427, a current sensor 428, and various interfaces. The processor 422 executes program instructions stored in the memory 424 to perform various processes for controlling the drive motor 520. The converter circuit 425 rectifies AC power supplied from a commercial power source into DC power. Based on instructions from the processor 422, the inverter circuit 426 converts the DC power rectified by the converter circuit 425 into three-phase AC power supplied to the drive motor 520 using pulse width modulation (PWM). The voltage sensor 427 detects a DC voltage CV2 output from the converter circuit 425 and an output voltage MV2 output to the drive motor 520. The current sensor 428 detects the output current MI2 output to the drive motor 520. In this embodiment, the inverter device 420 is an inverter device with the same specifications as the inverter device 410.

[0022] The inverter device 420 controls the drive motor 520 by sensorless vector control by referring to the output current MI2 and output voltage MV2 output from the inverter device 420 to the drive motor 520. The inverter device 420 outputs an estimated output torque value TE2 estimated as the output torque of the drive motor 520 in the sensorless vector control to the two-axis control device 300. In this embodiment, the inverter device 420 smoothes the value calculated as the output torque of the drive motor 520 in the sensorless vector control using a low-pass filter to remove noise, and outputs the value to the two-axis control device 300 as the estimated output torque value TE2.

[0023] When the inverter device 420 determines that the drive motor 520 is in an overload state, it executes overload protection control to protect the drive motor 520 from an overload. When the estimated output torque value TE2 exceeds a torque limit value (for example, 210% of the rated torque of the drive motor 520), the inverter device 420 determines that the drive motor 520 is in an overload state. In this case, the inverter device 420 controls the drive motor 520 as overload protection control so that torque exceeding the torque limit value is not generated. Furthermore, when the regenerative energy of the drive motor 520 becomes excessive during deceleration of the drive motor 520 and the DC voltage CV2 output from the converter circuit 425 exceeds a voltage limit value (for example, 190% (380 V) of the power supply voltage (200 V)), the inverter device 420 determines that the drive motor 520 is in an overload state. In this case, the inverter device 420 stops decreasing the frequency of the output power to the drive motor 520 as overload protection control.

[0024] While the inverter device 420 is executing overload protection control for the drive motor 520, it outputs an overload warning signal A2 indicating the execution of overload protection control to the two-axis control device 300. In this embodiment, the overload warning signal A2 indicates a value of "0" when overload protection control is not being executed, and indicates a value of "1" when overload protection control is being executed.

[0025] The drive motor 510 of the crusher 10 drives the rotating shaft 210 to rotate. The drive motor 510 is a three-phase induction drive motor. The drive motor 510 outputs rotational power to an output shaft 512 based on three-phase AC supplied from the inverter device 410. The rotational power of the drive motor 510 is transmitted to the rotating shaft 210 via a reducer 610 connected to the output shaft 512.

[0026] The drive motor 520 of the crusher 10 drives the rotating shaft 220 to rotate. The drive motor 520 is a three-phase induction drive motor. In this embodiment, the drive motor 520 is a three-phase induction drive motor with the same specifications as the drive motor 510. The drive motor 520 outputs rotational power to an output shaft 522 based on three-phase AC supplied from the inverter device 420. The rotational power of the drive motor 520 is transmitted to the rotating shaft 220 via a reducer 620 connected to the output shaft 522.

[0027] The reducer 610 of the crusher 10 reduces the rotational power output from the drive motor 510 and transmits it to the rotating shaft 210. The reducer 610 is a mechanical device equipped with a plurality of gears. In this embodiment, when the inverter device 410 drives the drive motor 510 with a three-phase AC of 60 Hz (Hertz), the rotational power of the output shaft 512 is reduced via the reducer 610, causing the rotating shaft 210 to rotate at approximately 10 rpm (revolutions per minute). The rotation speeds of the drive motor 510 and the rotating shaft 210 increase in proportion to an increase in the frequency of the three-phase AC supplied from the inverter device 410, and decrease in proportion to a decrease in that frequency.

[0028] The reducer 620 of the crusher 10 reduces the rotational power output from the drive motor 520 and transmits it to the rotating shaft 220. The reducer 620 is a mechanical device equipped with a plurality of gears. In this embodiment, the reducer 620 is a mechanical device with the same specifications as the reducer 610.

[0029] The two-shaft control device 300 of the crusher 10 controls the operation of the rotating shaft 210 and the rotating shaft 220. The two-shaft control device 300 is a computer equipped with a processor 310, a memory 320, and various interfaces. The two-shaft control device 300 controls one of the rotating shafts 210 and 220 as a high-speed drive shaft SF, and the other as a low-speed drive shaft SL. The two-shaft control device 300 switches between the high-speed drive shaft SF and the low-speed drive shaft SL every predetermined operating time (e.g., 60 minutes) in order to equalize wear on each part of the crusher 10.

[0030] When the rotating shaft 210 is set as the high-speed drive shaft SF (first rotating shaft) and the rotating shaft 220 is set as the low-speed drive shaft SL (second rotating shaft), the inverter device 410 is set as the high-speed inverter device IF (first inverter device) and the drive motor 510 is set as the high-speed drive motor MF (first drive motor). In this case, the inverter device 420 is set as the low-speed inverter device IL (second inverter device) and the drive motor 520 is set as the low-speed drive motor ML (second drive motor). The inverter device 410, which is the high-speed inverter device IF, outputs an estimated output torque value TE1 to the two-axis control device 300 as an estimated output torque value TF (first estimated output torque value), and also outputs an overload warning signal A1 to the two-axis control device 300 as a high-speed warning signal AF from the high-speed inverter device IF. The inverter device 420, which is the low-speed side inverter device IL, outputs the estimated output torque value TE2 to the two-axis control device 300 as the estimated output torque value TL (second estimated output torque value).

[0031] When the rotating shaft 220 is set as the high-speed drive shaft SF (first rotating shaft) and the rotating shaft 210 is set as the low-speed drive shaft SL (second rotating shaft), the inverter device 420 is set as the high-speed inverter device IF (first inverter device) and the drive motor 520 is set as the high-speed drive motor MF (first drive motor). In this case, the inverter device 410 is set as the low-speed inverter device IL (second inverter device) and the drive motor 510 is set as the low-speed drive motor ML (second drive motor). The inverter device 420, which is the high-speed inverter device IF, outputs an estimated output torque value TE2 to the two-axis control device 300 as an estimated output torque value TF (first estimated output torque value), and also outputs an overload warning signal A2 to the two-axis control device 300 as a high-speed warning signal AF from the high-speed inverter device IF. The inverter device 410, which is the low-speed side inverter device IL, outputs the estimated output torque value TE1 to the two-axis control device 300 as the estimated output torque value TL (second estimated output torque value).

[0032] The two-axis control device 300 calculates a torque moving average value TFA, which is a moving average value of the estimated output torque values ​​TF input from the high-speed inverter device IF. In this embodiment, the two-axis control device 300 extracts the four most recent estimated output torque values ​​TF and calculates the torque moving average value TFA from these four estimated output torque values ​​TF. The number of estimated output torque values ​​TF used to calculate the torque moving average value TFA may be other than four and can be set appropriately depending on the configuration of the crusher 10.

[0033] The two-axis control device 300 calculates a torque moving average value TLA, which is a moving average value of the estimated output torque values ​​TL input from the low-speed inverter device IL. In this embodiment, the two-axis control device 300 extracts the four most recent estimated output torque values ​​TL and calculates the torque moving average value TLA from these four estimated output torque values ​​TL. The number of estimated output torque values ​​TL from which the torque moving average value TLA is calculated may be other than four and can be set appropriately depending on the configuration of the crusher 10.

[0034] If the torque moving average value TFA is equal to or greater than the torque limit value TFmax, the two-axis control device 300 instructs the high-speed inverter device IF to drive the high-speed drive motor MF in the reverse direction RR (70 Hz drive in this embodiment). On the other hand, if the torque moving average value TFA is less than the torque limit value TFmax, the two-axis control device 300 instructs the high-speed inverter device IF to drive the high-speed drive motor MF in the forward rotation direction FR at a first rotation speed (60 Hz drive in this embodiment).

[0035] Furthermore, when the torque moving average value TLA is equal to or greater than the torque limit value TLmax, the two-axis control device 300 instructs the low-speed inverter device IL to drive the low-speed drive motor ML in the reverse direction RR (70 Hz drive in this embodiment).

[0036] On the other hand, if the torque moving average value TLA is less than the torque limit value TLmax and the high-speed side warning signal AF does not indicate the execution of overload protection control for the high-speed side drive motor MF, the two-axis control device 300 instructs the low-speed side inverter device IL to drive the low-speed side drive motor ML in a rotation direction corresponding to the torque moving average value TFA and at a rotation speed slower than the first rotation speed corresponding to the torque moving average value TFA (in this embodiment, driving at 6 Hz, 4.5 Hz or 3 Hz in the forward direction FR, and driving at 30 Hz in the reverse direction RR).

[0037] Furthermore, when the torque moving average value TLA is less than the torque limit value TLmax and the high-speed side warning signal AF indicates that overload protection control should be performed on the high-speed side drive motor MF, the two-axis control device 300 instructs the low-speed side inverter device IL to drive the low-speed side drive motor ML in the reverse direction RR (at 6 Hz in this embodiment). The responsiveness of detecting an overload on the high-speed drive shaft SF based on the high-speed side warning signal AF is higher than that of the torque moving average value TFA, which is the moving average value of the estimated output torque value TF smoothed by a low-pass filter. Therefore, an overload on the high-speed drive shaft SF that cannot be completely avoided by control based on the torque moving average value TFA can be prevented by control based on the high-speed side warning signal AF.

[0038] Fig. 3 is a flowchart showing the two-axis control process executed by the processor 310 of the two-axis control device 300. The two-axis control process of Fig. 3 is a process for controlling the operation of the rotating shaft 210 and the rotating shaft 220. The processor 310 of the two-axis control device 300 executes program instructions stored in the memory 320 to repeatedly execute the two-axis control process of Fig. 3 at predetermined timings.

[0039] 3 starts, the processor 310 of the two-axis control device 300 determines whether it is time to switch the high-speed drive shaft SF and the low-speed drive shaft SL between the rotating shaft 210 and the rotating shaft 220 (step S110). In this embodiment, the processor 310 determines that it is time to switch the high-speed drive shaft SF and the low-speed drive shaft SL between the rotating shaft 210 and the rotating shaft 220. In this embodiment, the processor 310 determines that it is time to switch the high-speed drive shaft SF and the low-speed drive shaft SL between the rotating shaft 210 and the rotating shaft 220 if 60 minutes have passed since the previous axis setting timing and crushing processing is being performed.

[0040] If it is axis setting timing (step S110: "YES"), the processor 310 of the two-axis control device 300 switches the setting of the rotating axis 210 and the rotating axis 220 between the high-speed drive axis SF and the low-speed drive axis SL (step S120). For example, if the axis setting timing occurs when the rotating axis 210 is set as the high-speed drive axis SF and the rotating axis 220 is set as the low-speed drive axis SL, the processor 310 sets the rotating axis 220 as the high-speed drive axis SF and the rotating axis 210 as the low-speed drive axis SL. Conversely, if the axis setting timing occurs when the rotating axis 220 is set as the high-speed drive axis SF and the rotating axis 210 is set as the low-speed drive axis SL, the processor 310 sets the rotating axis 210 as the high-speed drive axis SF and the rotating axis 220 as the low-speed drive axis SL.

[0041] If it is not the timing for axis setting (step S110: "NO"), or after switching between the high-speed drive shaft SF and the low-speed drive shaft SL (step S120), the processor 310 of the two-axis control device 300 reads the estimated output torque value TF of the high-speed drive motor MF input from the high-speed inverter device IF and the high-speed warning signal AF into memory 320, and also reads the estimated output torque value TL of the low-speed drive motor ML input from the low-speed inverter device IL into memory 320 (step S130).

[0042] After reading various signals from the high-speed inverter device IF and the low-speed inverter device IL (step S130), the processor 310 of the two-axis control device 300 calculates a torque moving average value TFA, which is a moving average value of the estimated output torque values ​​TF input from the high-speed inverter device IF (step S140). The processor 310 reads a predetermined number (four in this embodiment) of the most recent estimated output torque values ​​TF from the memory 320, and calculates the torque moving average value TFA from these estimated output torque values ​​TF. The processor 310 stores the torque moving average value TFA in the memory 320.

[0043] After calculating the torque moving average value TFA (step S140), the processor 310 of the two-axis control device 300 calculates a torque moving average value TLA, which is a moving average value of the estimated output torque values ​​TL input from the low-speed inverter device IL (step S150). The processor 310 reads out a predetermined number (four in this embodiment) of the most recent estimated output torque values ​​TL from the memory 320, and calculates the torque moving average value TLA from these estimated output torque values ​​TL. The processor 310 stores the torque moving average value TLA in the memory 320.

[0044] After calculating the torque moving average value TLA (step S150), the processor 310 of the two-axis control device 300 executes a high-speed axis control process (step S200) and a low-speed axis control process (step S300). The high-speed axis control process (step S200) is a process for controlling the rotation of the high-speed drive shaft SF. The low-speed axis control process (step S300) is a process for controlling the rotation of the low-speed drive shaft SL. After completing the high-speed axis control process (step S200) and the low-speed axis control process (step S300), the processor 310 ends the two-axis control process of FIG. 3.

[0045] 4 is a flowchart showing the high speed axis control process (step S200) executed by the processor 310 of the two-axis control device 300. After starting the high speed axis control process (step S200), the processor 310 reads out the torque moving average value TFA of the high speed drive motor MF from the memory 320 (step S210).

[0046] After reading out the torque moving average value TFA of the high-speed drive motor MF (step S210), the processor 310 of the two-axis control device 300 determines whether the torque moving average value TFA read out from the memory 320 is equal to or greater than the torque limit value TFmax (step S220). In this embodiment, the torque limit value TFmax is set to 200% of the rated torque of the high-speed drive motor MF. In other embodiments, the torque limit value TFmax may be less than 200% of the rated torque of the high-speed drive motor MF, or may be greater than 200% of the rated torque of the high-speed drive motor MF.

[0047] If the torque moving average value TFA of the high-speed drive motor MF is less than the torque limit value TFmax (step S220: "NO"), the processor 310 of the two-axis control device 300 instructs the high-speed inverter device IF to drive the high-speed drive motor MF in a forward rotation operation (step S230). The forward rotation operation of the high-speed drive motor MF (step S230) is a control to rotate the high-speed drive shaft SF in the forward rotation direction FR at a speed sufficient to crush the waste 810. In this embodiment, in the forward rotation operation of the high-speed drive motor MF (step S230), the processor 310 instructs the high-speed inverter device IF to drive the high-speed drive motor MF in the forward rotation direction FR with three-phase AC having a frequency of 60 Hz (first rotation speed). After instructing the high-speed inverter device IF to perform the forward rotation operation of the high-speed drive motor MF (step S230), the processor 310 ends the high-speed axis control process (step S200) of FIG. 4.

[0048] If the torque moving average value TFA of the high-speed drive motor MF is equal to or greater than the torque limit value TFmax (step S220: "YES"), the processor 310 of the two-axis control device 300 instructs the high-speed inverter unit IF to drive the high-speed drive motor MF in reverse rotation (step S240). The reverse rotation of the high-speed drive motor MF (step S240) is a control to rotate the high-speed drive shaft SF in the reverse direction RR to prevent damage to the crusher 10 due to excessive load on the high-speed drive shaft SF. In this embodiment, in the reverse rotation of the high-speed drive motor MF (step S240), the processor 310 instructs the high-speed inverter unit IF to drive the high-speed drive motor MF in the reverse direction RR with three-phase AC at a frequency of 70 Hz. In this embodiment, the frequency (70 Hz) at which the high-speed drive motor MF is driven in the reverse rotation (step S240) is higher than the frequency (60 Hz) at which the high-speed drive motor MF is driven in the forward rotation (step S230). In other embodiments, the frequency of the reverse rotation operation (step S240) may be the same as or lower than the frequency of the forward rotation operation (step S230). After instructing the high-speed inverter device IF to perform the reverse rotation operation of the high-speed drive motor MF (step S240), the processor 310 ends the high-speed axis control process (step S200) in FIG.

[0049] 5 is a flowchart showing the slow-speed axis control process (step S300) executed by the processor 310 of the two-axis control device 300. After starting the slow-speed axis control process (step S300), the processor 310 reads out the torque moving average value TFA of the high-speed drive motor MF, the high-speed warning signal AF, and the torque moving average value TLA of the low-speed drive motor ML from the memory 320 (step S310).

[0050] After reading out the torque moving average value TFA, the high-speed side warning signal AF, and the torque moving average value TLA (step S310), the processor 310 of the two-axis control device 300 determines whether the torque moving average value TLA of the low-speed side drive motor ML read out from the memory 320 is equal to or greater than the torque limit value TLmax (step S320). In this embodiment, the torque limit value TLmax is set to 200% of the rated torque of the low-speed side drive motor ML. In other embodiments, the torque limit value TLmax may be less than 200% of the rated torque of the low-speed side drive motor ML, or may be greater than 200% of the rated torque of the low-speed side drive motor ML.

[0051] If the torque moving average value TLA of the low-speed drive motor ML is equal to or greater than the torque limit value TLmax (step S320: "YES"), the processor 310 of the two-axis control device 300 instructs the low-speed inverter unit IL to drive the low-speed drive motor ML in a reverse operation (step S325). The reverse operation of the low-speed drive motor ML (step S325) is a control to rotate the low-speed drive shaft SL in the reverse direction RR to prevent damage to the crusher 10 due to an excessive load on the low-speed drive shaft SL. In this embodiment, in the reverse operation of the low-speed drive motor ML (step S325), the processor 310 instructs the low-speed inverter unit IL to drive the low-speed drive motor ML in the reverse direction RR with three-phase AC current having a frequency of 70 Hz (second rotation speed). In this embodiment, the frequency (70 Hz) at which the low-speed drive motor ML is driven in the reverse rotation (step S325) is higher than the frequency (60 Hz) at which the high-speed drive motor MF is driven in the forward rotation (step S230 in FIG. 4). In other embodiments, the frequency of the reverse rotation (step S325) may be the same as the frequency of the forward rotation (step S230 in FIG. 4) of the high-speed drive motor MF, or may be lower than the frequency of the forward rotation (step S230 in FIG. 4) of the high-speed drive motor MF. After instructing the low-speed inverter device IL to perform the reverse rotation (step S325) of the low-speed drive motor ML, the processor 310 ends the low-speed shaft control process (step S300) in FIG. 5.

[0052] If the torque moving average value TLA of the low-speed drive motor ML is less than the torque limit value TLmax (step S320: "NO"), the processor 310 of the two-axis control device 300 determines whether the high-speed warning signal AF has a value of "1", i.e., whether the high-speed inverter device IF is performing overload protection control (step S330).

[0053] If the high-speed warning signal AF is set to "1," i.e., if the high-speed inverter IF is executing overload protection control (step S330: "YES"), the processor 310 of the two-axis control device 300 instructs the low-speed inverter IL to drive the low-speed drive motor ML in a reverse direction (step S335). The reverse operation of the low-speed drive motor ML (step S335) is a control for rotating the low-speed drive shaft SL in the reverse direction RR to reduce the overload on the high-speed drive shaft SF that is under overload protection control. In this embodiment, in the reverse operation of the low-speed drive motor ML (step S335), the processor 310 instructs the low-speed inverter IL to drive the low-speed drive motor ML in the reverse direction RR with three-phase AC current having a frequency of 6 Hz (third rotation speed). In this embodiment, the frequency (6 Hz) of the reverse rotation operation based on the high-speed side warning signal AF (step S335) is lower than the frequency (70 Hz) of the reverse rotation operation based on the torque moving average value TLA (step S325). After instructing the low-speed side inverter device IL to perform the reverse rotation operation of the low-speed side drive motor ML (step S335), the processor 310 ends the low-speed shaft control process (step S300) in Figure 5.

[0054] If the high-speed side warning signal AF has a value of "0", i.e., if the high-speed side inverter device IF is not performing overload protection control (step S330: "NO"), the processor 310 of the two-axis control device 300 determines whether the torque moving average value TFA of the high-speed side drive motor MF is greater than or equal to 150% and less than 200% of the rated torque (step S340).

[0055] If the torque moving average value TFA of the high-speed drive motor MF is equal to or greater than 150% and less than 200% of the rated torque (step S340: "YES"), the processor 310 of the two-axis control device 300 instructs the low-speed inverter device IL to drive the low-speed drive motor ML in a reverse operation (step S345). The reverse operation of the low-speed drive motor ML (step S345) is a control to rotate the low-speed drive shaft SL in the reverse direction RR to reduce overload on the high-speed drive shaft SF. In this embodiment, in the reverse operation of the low-speed drive motor ML (step S345), the processor 310 instructs the low-speed inverter device IL to drive the low-speed drive motor ML in the reverse direction RR with three-phase AC at a frequency of 30 Hz. In this embodiment, the frequency (30 Hz) of the reverse operation based on the torque moving average value TFA (step S345) is higher than the frequency (70 Hz) of the reverse operation based on the torque moving average value TLA (step S325). After instructing the low speed side inverter device IL to perform the reverse rotation operation of the low speed side drive motor ML (step S345), the processor 310 ends the low speed shaft control process (step S300) in FIG.

[0056] If the torque moving average value TFA of the high-speed drive motor MF is less than 150% of the rated torque (step S340: "NO"), the processor 310 of the two-axis control device 300 determines whether the torque moving average value TFA of the high-speed drive motor MF is greater than or equal to 80% and less than 150% of the rated torque (step S350).

[0057] If the torque moving average value TFA of the high-speed drive motor MF is equal to or greater than 80% and less than 150% of the rated torque (step S350: "YES"), the processor 310 of the two-axis control device 300 instructs the low-speed inverter unit IL to drive the low-speed drive motor ML in forward rotation (step S355). The forward rotation of the low-speed drive motor ML (step S355) is a control that rotates the low-speed drive shaft SL in the forward rotation direction FR to continue the crushing process when the load on the high-speed drive shaft SF is relatively high. In this embodiment, in the forward rotation of the low-speed drive motor ML (step S355), the processor 310 instructs the low-speed inverter unit IL to drive the low-speed drive motor ML in the forward rotation direction FR with three-phase AC at a frequency of 3 Hz. In this embodiment, the frequency (3 Hz) for controlling the low-speed drive motor ML in the forward rotation operation (step S355) is lower than the frequency (60 Hz) for driving the high-speed drive motor MF in the forward rotation operation (step S230 in FIG. 4). After instructing the low-speed inverter device IL to perform the forward rotation operation of the low-speed drive motor ML (step S355), the processor 310 ends the low-speed shaft control process (step S300) in FIG.

[0058] If the torque moving average value TFA of the high-speed drive motor MF is less than 80% of the rated torque (step S350: "NO"), the processor 310 of the two-axis control device 300 determines whether the torque moving average value TFA of the high-speed drive motor MF is greater than or equal to 30% and less than 80% of the rated torque (step S360).

[0059] If the torque moving average value TFA of the high-speed drive motor MF is equal to or greater than 30% and less than 80% of the rated torque (step S360: "YES"), the processor 310 of the two-axis control device 300 instructs the low-speed inverter unit IL to drive the low-speed drive motor ML in forward rotation (step S365). The forward rotation of the low-speed drive shaft SL (step S365) is a control to rotate the low-speed drive shaft SL in the forward rotation direction FR to continue the crushing process when the load on the high-speed drive shaft SF is moderate. In this embodiment, in the forward rotation of the low-speed drive shaft SL (step S365), the processor 310 instructs the low-speed inverter unit IL to drive the low-speed drive motor ML in the forward rotation direction FR with three-phase AC at a frequency of 4.5 Hz. In this embodiment, the frequency (4.5 Hz) for controlling the low-speed drive motor ML in the forward rotation operation (step S365) is lower than the frequency (60 Hz) for driving the high-speed drive motor MF in the forward rotation operation (step S230 in FIG. 4) and higher than the frequency (3 Hz) for controlling the low-speed drive motor ML in the forward rotation operation (step S355). After instructing the low-speed inverter device IL to perform the forward rotation operation of the low-speed drive shaft SL (step S365), the processor 310 ends the low-speed shaft control process (step S300) in FIG. 5.

[0060] If the torque moving average value TFA of the high-speed drive motor MF is equal to or greater than 0% and less than 30% of the rated torque (step S360: "NO"), the processor 310 of the two-axis control device 300 instructs the low-speed inverter unit IL to drive the low-speed drive motor ML in forward rotation (step S375). The forward rotation of the low-speed drive shaft SL (step S375) is a control to continue the crushing process by rotating the low-speed drive shaft SL in the forward rotation direction FR when the load on the high-speed drive shaft SF is relatively low. In this embodiment, in the forward rotation of the low-speed drive shaft SL (step S375), the processor 310 instructs the low-speed inverter unit IL to drive the low-speed drive motor ML in the forward rotation direction FR with three-phase AC at a frequency of 6 Hz. In this embodiment, the frequency (6 Hz) for controlling the low-speed drive motor ML in the forward rotation operation (step S375) is lower than the frequency (60 Hz) for driving the high-speed drive motor MF in the forward rotation operation (step S230 in FIG. 4) and higher than the frequency (4.5 Hz) for controlling the low-speed drive motor ML in the forward rotation operation (step S365). After instructing the low-speed inverter device IL to perform the forward rotation operation of the low-speed drive shaft SL (step S375), the processor 310 ends the low-speed shaft control process (step S300) in FIG. 5.

[0061] According to the embodiment described above, overload of the high-speed drive shaft SF, which cannot be completely avoided by controlling the low-speed drive motor ML based on the high-speed warning signal AF, which is an overload warning signal for the high-speed drive motor MF, in accordance with the torque moving average value TFA of the high-speed drive motor MF (steps S345, S355, S365, S375), can be avoided by controlling the low-speed drive motor ML based on the high-speed warning signal AF, which is an overload warning signal for the high-speed drive motor MF. As a result, sudden stops due to overload of the high-speed drive shaft SF can be prevented, making it easy to achieve both work efficiency and a safety factor.

[0062] The technology disclosed in this specification is not limited to the above-described embodiments, examples, and modifications, and can be realized in various configurations without departing from the spirit thereof. For example, among the technical features of the above-described embodiments, examples, and modifications, those corresponding to the technical features of each form described in the Summary of the Invention section can be appropriately replaced and combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, technical features not described as essential in this specification can be appropriately deleted.

[0063] In the above-described embodiment, the shredder 10 performs the shredding process by driving the high-speed drive shaft SF in the forward direction FR at a constant rotation speed while driving the low-speed drive shaft SL in the forward direction FR at three rotation speed levels corresponding to the torque moving average value TFA. In other embodiments, the shredder 10 may perform the shredding process by driving the high-speed drive shaft SF in the forward direction FR at multiple rotation speed levels corresponding to the torque moving average value TFA. The shredder 10 may also perform the shredding process by driving the low-speed drive shaft SL in the forward direction FR at a constant rotation speed. The shredder 10 may also perform the shredding process by driving the low-speed drive shaft SL in the forward direction FR at two or four or more rotation speed levels corresponding to the torque moving average value TFA.

[0064] Furthermore, the inverter devices 410, 420 may delay the timing at which they start outputting the high-speed warning signal AF to the two-axis control device 300. This makes it possible to prevent the low-speed drive motor ML from momentarily rotating in the forward direction (step S355 in FIG. 5) based on the high-speed warning signal AF. As a result, the efficiency of the crushing process can be improved.

[0065] Furthermore, the frequency of the reverse rotation of the low-speed drive motor ML (steps S325, S335) can be set appropriately depending on the configuration of the crusher 10. [Explanation of symbols]

[0066] 10...Crusher 110... Treatment container 112...Intake port 118...Exhaust port 210, 220...Rotation axis 212,222...Crushing blade 214,224...Spacer 300...Two-axis control device 310...Processor 320...Memory 410, 420...Inverter device 412,422...processor 414,424...memory 415,425...Converter circuit 416, 426...Inverter circuit 417,427...Voltage sensor 418,428...Current sensor 510, 520...Drive motor 512,522...Output shaft 610,620...Reducer 810...Waste 820...Fragments

Claims

[Claim 1] a first rotating shaft having a first crushing blade provided on its outer periphery; A second rotating shaft is arranged parallel to the first rotating shaft and has a second crushing blade provided on its outer periphery, A shredder that shreds waste sent between the first shredding blade and the second shredding blade by rotating the first rotating shaft and the second rotating shaft in a forward direction, a two-axis control device that controls the operation of the first rotation axis and the second rotation axis; a first drive motor that rotates and drives the first rotary shaft; a first inverter device that controls the rotation of the first drive motor by first sensorless vector control based on an instruction from the two-axis control device; a second drive motor that rotates the second rotary shaft; a second inverter device that controls the rotation of the second drive motor by second sensorless vector control based on an instruction from the two-axis control device; Equipped with The first inverter device outputting a first estimated output torque value estimated as an output torque of the first drive motor in the first sensorless vector control to the two-axis control device; determining whether the first drive motor is in an overload state; When it is determined that the first drive motor is in an overload state, an overload protection control is executed to protect the first drive motor from an overload; When the overload protection control is executed, an overload warning signal indicating the execution of the overload protection control is output to the two-axis control device; the second inverter device outputs a second estimated output torque value estimated as an output torque of the second drive motor in the second sensorless vector control to the two-axis control device; The two-axis control device calculating a first torque moving average value that is a moving average value of the first estimated output torque value input from the first inverter device; calculating a second torque moving average value that is a moving average value of the second estimated output torque value input from the second inverter device; instructing the first inverter device to drive the first drive motor in a forward rotation direction at a first rotation speed when the first torque moving average value is less than a first torque limit value; instructing the first inverter device to drive the first drive motor in a reverse direction when the first torque moving average value is equal to or greater than the first torque limit value; when the second torque moving average value is less than a second torque limit value and the overload warning signal does not indicate execution of the overload protection control, instructing the second inverter device to drive the second drive motor in a rotation direction corresponding to the first torque moving average value and at a rotation speed slower than the first rotation speed corresponding to the first torque moving average value; instructing the second inverter device to drive the second drive motor in a reverse direction when the second torque moving average value is equal to or greater than the second torque limit value; the crusher instructs the second inverter device to drive the second drive motor in a reverse direction when the second torque moving average value is less than the second torque limit value and the overload warning signal indicates that the overload protection control is being executed.

Images