JP6010801B2 - Crane drive device and crane - Google Patents

Description

  The present invention relates to a crane drive device for hanging a load and a crane.

  As a crane used for loading (lifting or hanging) loads, for example, it is installed outdoors such as a quay of a harbor or a container yard, or indoors such as a building in a factory, etc. Traveling cranes that transport loads are widely known. And in such a traveling crane, the drive of the motor of a traveling apparatus is controlled by the inverter.

  By the way, for example, a slip may occur on a traveling wheel due to a change in a friction coefficient due to a load of a suspended load, a left-right load balance of the suspended load, freezing of a traveling surface of a traveling rail, and the like. It is necessary to quickly recover from the slip state.

  Here, in Patent Document 1, when the crane is in a slanting operation state due to the occurrence of slip or the like, the driving device of the preceding traveling wheel stops the increase of the output frequency by the stall prevention function of the inverter, and the motor A drive device is disclosed that reduces the load current to return from a skew operation state to an appropriate operation state.

JP-A-5-58586

  However, in the drive device disclosed in Patent Document 1, the traveling state is controlled based on only the load current of the motor of the preceding traveling wheel. Further, when the load current exceeds the upper limit and becomes overloaded, the load current is reduced by the stall prevention function of the inverter. For this reason, when the traveling wheel idles, the motor torque decreases, and the slip current cannot be determined when the load current of the motor is in a low current state. In particular, when falling into such a low current state, it takes time to recover from the slip. The inverter also has a function of detecting that the load current at the motor is in a low current (low torque) state, but does not adjust the load current of the motor according to the detected value.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide a crane driving device and a crane that suppress the occurrence of a slip phenomenon and enable early recovery from a slip state. And

In order to solve the above problems, the present invention employs the following means.
That is, the crane drive device according to the present invention corresponds to a pair of traveling units having traveling wheels traveling on the traveling paths provided on the left and right sides of the suspended body that suspends the load. A pair of drive units each having an inverter to be driven; and a detection unit that is provided in each of the pair of drive units and detects a current output from the inverter to the motor;
Based on the current detected by the respective front Symbol detector, and a controller for controlling the inverter corresponding to each of the detecting unit, wherein the control unit includes at least one detected by one of the detecting unit Whether or not the current that has been set is greater than an upper limit value that is set in association with a slip phenomenon , or whether the current is smaller than a lower limit value that is set in association with a slip phenomenon , When the current is smaller than the lower limit value , an acceleration speed command for the motor is sent to the inverter of the drive unit having the detection unit that detects the current smaller than the lower limit value. suppressing, when the current is greater than the upper limit, the inverter of the driving portion of the person with the detection unit detects the current becomes larger than the upper limit value To data, suppressing the speed command acceleration for the motor.

  According to such a drive device, when the traveling wheel in either the left or right traveling unit runs idle and a slip phenomenon occurs, the load on the slipping motor is reduced. The output current to becomes a low current state. On the other hand, in the motor of the drive unit corresponding to the traveling unit on the non-slip side, the load increases, and the output current to this motor is in an overcurrent state. And if it continues driving | running | working in such a state, a crane will run diagonally. Here, the lower limit value and the upper limit value are set in consideration of various conditions such as the weight of the suspended load in the crane and the left / right balance of the suspension for the output current in which the slip phenomenon occurs in this way. When the output current to the left and right motors exceeds these lower and upper limit values, the right and left motors can be quickly overcurrent and low current by suppressing the acceleration speed command to each motor. It is possible to return to the normal state from the state and adjust the load balance between the left and right motors. When the output current to one of the motors exceeds the upper limit value and the lower limit value, the acceleration speed command to both motors may be suppressed.

  Further, the control unit may suppress the acceleration speed command using a value at which the slip phenomenon occurs under a condition in which a load caused by the largest load is applied to one of the traveling sides as the upper limit value. .

  By setting the upper limit value in this way, it is possible to suppress the speed command with the condition where the slip phenomenon is most likely to occur as the upper limit, so it is possible to more reliably adjust the load balance between the left and right motors and suppress slip occurrence. And normal driving | running | working can be continued by the early return from a slip.

  Further, the control unit may suppress the acceleration speed command using the value at which the slip phenomenon occurs under a condition in which a load caused by the smallest load is applied to one of the traveling units as the lower limit value. Good.

  By setting the lower limit in this way, it is possible to suppress the speed command with the condition where slip phenomenon is most likely to occur as the lower limit, so the load balance in the left and right traveling parts can be adjusted more reliably, and slip occurrence can occur. The normal running can be continued by the suppression and the early return from the slip.

  The controller may perform a speed command for stopping acceleration of the motor for a predetermined time as the speed command in the inverter.

  In this way, by controlling the acceleration to zero, that is, by controlling the output current from the inverter to the motor and making the speed constant, the load balance between the left and right motors can be adjusted reliably, and the occurrence of the slip phenomenon The normal running can be continued by the suppression and the early return from the slip. Note that, after a predetermined time has elapsed, control is performed so that acceleration is started again after recovery from the slip.

  Furthermore, the control unit may perform a speed command for stopping the acceleration after gradually reducing the acceleration of the motor as the speed command for the inverter.

  In this way, acceleration is gradually stopped before the speed is kept constant, so smooth control can reduce the impact on components due to sudden deceleration and reduce the impact on suspended loads. Can do.

  Further, the control unit may perform a speed command for gradually increasing the acceleration after stopping the acceleration of the motor as the speed command for the inverter.

  By doing in this way, smoother control becomes possible, the impact on a component can be reduced, and the influence on a suspended load can be reduced.

  Furthermore, the control unit may perform a speed command for reducing acceleration as the speed command for the inverter.

  By doing in this way, compared with the case where acceleration is suddenly stopped, smoother control becomes possible, the impact on a component can be reduced, and the influence on a suspended load can be reduced.

  Furthermore, the control unit may issue a stop command to the motor as the speed command for the inverter or a speed command for accelerating in a direction opposite to the traveling direction of the traveling unit.

  By doing so, it is possible to decelerate and to return from slip earlier.

  The pair of drive units may have an overload resistance value of current in each of the motors larger than the upper limit value.

  By providing a margin for the motor power in this way, the output current to the motor is not suppressed by the stall prevention function in the inverter even though no slip has occurred. That is, it is possible to prevent such a state from being erroneously detected by the occurrence of slip and the control unit, and it is possible to more reliably suppress the occurrence of slip and to quickly return from the slip.

  Furthermore, the crane according to the present invention includes a pair of traveling units having the driving device described above, a suspended body that suspends a load, and traveling wheels that travel on traveling paths provided on the left and right sides of the suspended body. And comprising.

  According to such a crane, when the output current to the motor on each of the left and right exceeds the lower limit and upper limit corresponding to the slip phenomenon, the acceleration command to the left and right motors is suppressed by the drive device. By doing so, the left and right motors can be quickly returned from the overcurrent and low current states, and the load balance of the left and right motors can be adjusted.

  According to the crane drive device and crane of the present invention, the left and right drive units are monitored, and the speed command from the inverter to the drive units on both sides is controlled to suppress the occurrence of the slip phenomenon. In addition, early recovery from the slip state is possible.

It is a front view showing a crane concerning an embodiment of the present invention. It is an enlarged side view which shows the traveling part periphery of the crane which concerns on embodiment of this invention. It is a top view which simplifies and shows the crane which concerns on embodiment of this invention. FIG. 5 is a graph showing temporal changes in motor speed and current with respect to the crane according to the embodiment of the present invention, where (a) controls normal running and (b) controls the idling motor when a slip phenomenon occurs. (C) shows the case where the motor on the overload side at the time of occurrence of the slip phenomenon is controlled. It is a top view which simplifies and shows the crane which concerns on embodiment of this invention, Comprising: The state under diagonal running is shown. It is a graph which shows the time change of the speed at the time of controlling a motor from generation | occurrence | production of a slip phenomenon to a reset regarding the crane which concerns on the 1st modification of embodiment of this invention. It is a graph which shows the time change of the speed at the time of controlling a motor from generation | occurrence | production of a slip phenomenon to a return regarding the crane which concerns on the 2nd modification of embodiment of this invention. It is a graph which shows the time change of the speed at the time of controlling a motor from generation | occurrence | production of a slip phenomenon to a reset regarding the crane which concerns on the 3rd modification of embodiment of this invention.

Hereinafter, the crane 1 which concerns on embodiment of this invention is demonstrated.
As shown in FIGS. 1 and 2, the crane 1 of the present embodiment is an indoor overhead crane arranged near the ceiling 101 in the building 100. Specifically, on both sides of the building 100 near the ceiling 101 in the left-right direction (left-right direction toward the paper surface of FIG. 1), the front-rear direction (direction toward the paper surface of FIG. 1) orthogonal to the left-right direction on the same horizontal plane. ) Is provided with a pair of traveling rails 107 (traveling paths). The crane 1 travels on the pair of traveling rails 107 with the load suspended.

  The crane 1 includes a crane main body (suspended body) 2 that suspends a load, a traveling unit 12 attached to the crane main body 2, and a drive device 21 that causes the crane main body 2 to travel by controlling the traveling unit 12. It has.

  The crane body 2 includes a trolley 4, a crane girder 6 on which the trolley 4 is placed, and a suspension means 3 provided on the trolley 4.

  The trolley 4 has a plurality of (four in this embodiment) trolley traveling wheels 5 that rotate about a rotation axis extending in the front-rear direction on the crane girder 6, and these trolley traveling wheels 5 are driven. Thus, the crane girder 6 is moved in the left-right direction.

  The suspending means 3 includes a wire 3b suspended downward from the trolley 4, and a suspended load hook that suspends a load that is attached to the tip of the wire 3b and is movable upward by winding the wire 3b. 3a.

  The crane girder 6 includes a girder body 8 that extends in the left-right direction and spans the left and right sides of the building 100, a trolley travel rail 11 that extends in the left-right direction on the girder body 8, and a girder. And yokes 9 provided on both sides of the main body 8 in the left-right direction. The trolley traveling wheel 5 rolls on the trolley traveling rail 11.

  Each yoke 9 is provided so as to support the girder body 8 from below at both lateral sides of the girder body 8, and is connected to the girder body 8 by yoke pins 10 extending in the left-right direction.

  Two traveling units 12 are provided in the left-right direction in this embodiment. More specifically, one traveling unit 12 is provided at each of the left and right and front and rear ends of the crane body 2. One traveling unit 12 may be provided on each of the left and right sides, and the number of installed units is not limited to the case of the present embodiment.

  Each traveling portion 12 includes a main body portion 13 attached to the lower side of the yoke 9 by a track pin 14 extending in the left-right direction, and a traveling wheel 15 provided on the main body portion 13 and rotated about a rotation axis extending in the left-right direction. And have.

  In the present embodiment, two main body parts 13 are provided at intervals in the front-rear direction in each traveling part 12, and each main body part 13 is provided with two traveling wheels 15 arranged side by side in the front-rear direction. Then, the traveling wheels 15 arranged in front and rear roll on the traveling rail 107. In this way, the crane body 2 is movable in the front-rear direction.

Next, the drive device 21 will be described with reference to FIG.
The drive device 21 is based on a drive unit 22 having a motor 23 that travels the traveling unit 12, a detection unit 31 that detects an output current of the drive unit 22 to the motor 23, and a current value detected by the detection unit 31. And a control unit 32 that controls the output current to the motor 23.

  The drive unit 22 is provided with a pair on the left and right. That is, one drive unit 22 has a dedicated motor 23 for rotating the traveling wheels 15 in the two traveling units 12 on the left side and a dedicated inverter 24 for driving the motor 23. Similarly, the other drive unit 22 The drive unit 22 includes a dedicated motor 23 that rotates the traveling wheels 15 in the two right traveling units 12 and a dedicated inverter 24 that drives the motor 23.

  The detection unit 31 includes a current sensor that detects an output current from the inverter 24 to the motor 23, and outputs a signal corresponding to the detected current magnitude to the control unit 32. Various current sensors can be used, and examples include a magnetic sensor.

  The control unit 32 receives a signal corresponding to the current value from the detection unit 31 and controls the magnitude of the output current from the inverter 24 to the motor 23 according to the value of this current. Sequence control using Programmable Logic Controller is performed.

  The control unit 32 monitors the value of the current detected by the detection unit 31, and the detection unit 31 detects the upper limit threshold value (upper limit value) and the lower limit threshold value (lower limit value) set in advance. The value of the output current from each inverter 24 to each motor 23 is changed by comparing the current value.

  Here, the traveling unit 12 travels due to factors such as the position of the trolley 4 on the crane girder 6, the load of the suspended load, the left / right load balance of the suspended load, and the change in the friction coefficient on the traveling rail 107 due to freezing. The wheel 15 may idle and a slip phenomenon may occur. When the traveling wheel 15 idles in either the left or right traveling unit 12 and a slip phenomenon occurs, the load on the motor 23 is reduced on the idling side. The output current to 23 is in a low current state. On the other hand, in the motor 23 of the drive unit 22 corresponding to the traveling unit 12 on the non-slip side, the load on the motor 23 increases, and the output current to the motor 23 is in an overcurrent (overtorque) state.

Accordingly, the lower limit threshold and the upper limit threshold compared by the control unit 32 are the conditions that cause the slip phenomenon (for example, the load of the suspended load, the left / right load balance of the suspended load, the friction coefficient on the traveling rail due to freezing, etc. The value calculated based on the condition determined by the change of
In the present embodiment, as an example, the lower limit threshold value and the upper limit threshold value are set under conditions where such a slip phenomenon is most likely to occur.

  Specifically, the condition in which the slip phenomenon is most likely to occur is that the suspended load and the trolley 4 are close to one of the left and right directions, and the largest load is applied to one of the left and right traveling parts 12, and the other This is a condition when the smallest load is applied to the traveling unit 12 and load imbalance occurs.

  Therefore, in the present embodiment, the minimum value is set as the lower limit threshold and the maximum value is set as the upper limit among the design values of the output current to the motor 23 that can normally run without occurrence of a slip phenomenon under such conditions. It is set as the threshold value. In other words, the design value means that when the output current to the motor 23 is smaller than the minimum value of the design value or larger than the maximum value of the design value, It means a numerical value that causes idling.

  In such a crane 1, during normal traveling in which no slip phenomenon occurs, the load on the motor 23 is constant during acceleration as shown in FIG. The output current is also substantially constant (a state within a predetermined fluctuation range).

  Here, as shown in FIG. 5, during traveling, the traveling wheel 15 in the traveling unit 12 in one of the left and right directions (in this embodiment, the left side as viewed in FIG. 5) slips and slip occurs. When traveling continues as it is, the other traveling unit 12 precedes one traveling unit 12 and the crane 1 travels obliquely.

  At this time, since the load on the motor 23 decreases in the left traveling unit 12, the output current from the inverter 24 to the motor 23 is low during the slip as shown in the upper graph of FIG. It becomes a state. Therefore, when the output current to the motor 23 exceeds the above-mentioned lower limit threshold and becomes smaller than this threshold, it is assumed that the slip phenomenon has occurred or that the slip phenomenon may occur, as shown in FIG. As shown in the lower stage, the acceleration is interrupted for a predetermined time, and the speed command is suppressed so as to keep the speed of the motor 23 constant. Here, the predetermined time indicates a time when the threshold value exceeds the lower limit threshold and becomes larger than the threshold value, or a time until a certain time elapses from this time point. After the predetermined time elapses, acceleration is performed again. Speed control.

  By doing so, it becomes possible for the traveling wheel 15 that is idling to recover grip to the traveling rail 107 and to recover to a normal traveling state.

Further, in the traveling unit 12 on the right side, as shown in the upper part of FIG. 4C, the load on the motor 23 increases, so that the output current from the inverter 24 to the motor 23 is in an overcurrent state during the slip. . Therefore, when the output current to the motor 23 exceeds the upper threshold and becomes larger than this threshold, it is assumed that the slip phenomenon has occurred or that the slip phenomenon may occur. As shown in FIG. 2, acceleration is interrupted for a predetermined time, and the acceleration speed command is suppressed so as to keep the speed of the motor 23 constant. Here, the predetermined time indicates a time when the upper limit threshold is exceeded and becomes smaller than this threshold, or a time until a certain time elapses from this time, and after the predetermined time elapses, acceleration is performed again. Speed control.
By doing so, it is possible to recover to the normal running state.

  In addition, since the lower limit threshold and the upper limit threshold are set under conditions where the slip phenomenon is most likely to occur, the occurrence of slip and early recovery from slip can be more reliably performed.

  According to the crane 1 of the present embodiment, the left and right drive units 22 are monitored, and the speed commands from the inverter 24 to the drive units 22 on both sides are controlled, so that the left and right motors 23 are quickly passed. The load balance of the left and right motors 23 can be adjusted by returning from the current and low current states. Therefore, the occurrence of the slip phenomenon is suppressed, the early return from the slip state is possible, and the normal traveling and the traversing can be continued.

  Here, as for the motor 23 in the drive part 22, it is more preferable that the overload tolerance value of an electric current is larger than the upper limit threshold value. By providing a margin for the power of the motor 23 in this way, the stall prevention function in the inverter 24 is activated even though the slip phenomenon has not occurred, and the output current to the motor 23 is suppressed. It wo n’t happen. That is, by operating such a stall prevention function, it is possible to prevent the control unit 32 from erroneously detecting that a slip phenomenon has occurred. Therefore, the occurrence of the slip phenomenon can be more reliably suppressed and the early return from the slip can be achieved.

  Moreover, when the output current to one of the motors 23 exceeds the upper limit value and the lower limit value, the acceleration speed command to both motors 23 may be suppressed. Early recovery is possible.

Next, a first modification of the present embodiment will be described.
In the first modification, the method for suppressing the acceleration speed command from the inverter 24 to the motor 23 in the control unit 32 is different from that described above.

  That is, as shown in FIG. 6, there is a possibility of occurrence of a slip phenomenon during acceleration, and when the output current to the motor 23 on each of the left and right exceeds the lower limit threshold or the upper limit threshold, the acceleration is increased. After gradually decreasing, the acceleration is stopped, and then a speed command is given to the inverter 24 to gradually increase the acceleration again.

  By doing in this way, smoother control becomes possible, the impact on the component due to a sudden acceleration change can be reduced, and the influence on the suspended load can be reduced. Note that only one of the acceleration reduction speed command before stopping acceleration and the acceleration increase speed command after stopping acceleration may be adopted.

Next, a second modification of the present embodiment will be described.
In the second modification, the method for suppressing the acceleration speed command from the inverter 24 to the motor 23 in the control unit 32 is different from that described above.

  As shown in FIG. 7, slip may occur during acceleration, or acceleration may not occur when the output current to the motor 23 on each of the left and right exceeds the lower limit threshold or the upper limit threshold. Then, a speed command for reducing the acceleration is issued to the inverter 24.

  Even in this way, since there is no sudden change in acceleration, smooth control is possible, impact on components can be reduced, and influence on suspended loads can be reduced.

Next, a third modification of the present embodiment will be described.
In the third modified example, the method of suppressing the acceleration speed command from the inverter 24 to the motor 23 in the control unit 32 is different from the above-described content.

  As shown in FIG. 8, when there is a possibility of occurrence of slip during acceleration, or when the output current to the motor 23 on each of the left and right exceeds a lower limit threshold or an upper limit threshold, a stop command is output. Alternatively, by outputting a speed command that accelerates in a direction opposite to the traveling direction of the traveling unit 12, a speed command that stops acceleration and decelerates in reverse is issued to the inverter 24.

  By doing so, it becomes possible to decelerate and to recover from the slip phenomenon at an earlier stage.

  Although the embodiment of the present invention has been described in detail above, some design changes can be made without departing from the technical idea of the present invention.

  For example, the traveling position of the crane 1, that is, the position in the front-rear direction on the traveling rail 107, the position where the output current to the motor 23 exceeds the lower threshold and the upper threshold, that is, the position where the slip phenomenon has occurred is recorded. You may keep statistics. By providing the control unit 32 and the like with an alarm device that issues an alarm at this position, the operator of the crane 1 can operate with the traveling speed reduced according to the alarm, and the trolley 4 can be traveled by removing this position. By doing so, it becomes possible to stably run.

  Further, by calculating the friction coefficient at the traveling rail 107 from the output current (torque) to the motor 23 when the slip phenomenon occurs and managing this by making a map or the like, it is possible to find a position where the friction coefficient is low. it can. Therefore, it is possible to warn that cleaning is necessary, or to check whether or not the rail is distorted and to correct the amount of distortion, thereby preventing the slip phenomenon.

  Further, the above-described slip control can be applied to traveling of the trolley 4 (hanging body) on the trolley traveling rail 11, that is, to the transverse operation.

  Furthermore, in the above-described embodiment, the crane 1 has been described as an overhead crane, but it can also be applied to, for example, a portal crane that loads and unloads outdoors.

DESCRIPTION OF SYMBOLS 1 ... Crane 2 ... Crane main body (suspended body) 3 ... Suspension means 3a ... Hook for suspended loads 3b ... Wire 4 ... Trolley 5 ... Trolley traveling wheel 6 ... Crane girder 8 ... Girder main body 9 ... Yoke 10 ... Yoke pin 11 ... Trolley travel rail 12 ... traveling section 13 ... main body section 15 ... running wheel 21 ... driving device 22 ... drive section 23 ... motor 24 ... inverter 31 ... detection section 32 ... control section 100 ... building 101 ... ceiling 107 ... running rail (traveling) Road)

Claims (10)

A pair of driving units having a motor and an inverter for driving the motor, corresponding to the pair of traveling units having traveling wheels traveling on the traveling path provided on the left and right sides of the suspended body that suspends the load;
A detection unit that is provided in each of the pair of drive units and detects a current output from the inverter to the motor;
Based on the respective front Symbol a current detected by the detection unit, a control unit for controlling the inverter corresponding to each of the detecting portion,
With
The controller is
Whether or not the current detected by at least one of the detection units is larger than an upper limit value set in association with a slip phenomenon , or lower than a lower limit value set in association with a slip phenomenon Monitor whether it ’s smaller ,
When the current is smaller than the lower limit value , an acceleration speed command for the motor is sent to the inverter of the drive unit having the detection unit that detects the current smaller than the lower limit value. Suppress
When the current is larger than the upper limit value, an acceleration speed command for the motor is sent to the inverter of the drive unit having the detection unit that detects the current larger than the upper limit value. Crane drive unit that suppresses.   2. The control unit according to claim 1, wherein, as the upper limit value, the acceleration speed command is suppressed using a value at which the slip phenomenon occurs under a condition in which a load caused by the largest load is applied to one of the traveling units. The crane drive device described.   2. The control unit according to claim 1, wherein the control unit suppresses the acceleration speed command using a value at which the slip phenomenon occurs under a condition in which a load caused by the smallest load is applied to one of the traveling units as the lower limit value. The crane drive device according to 2.   The crane driving device according to any one of claims 1 to 3, wherein the control unit performs a speed command for stopping acceleration of the motor for a predetermined time as the speed command in the inverter.   5. The crane drive device according to claim 4, wherein the control unit performs a speed command for stopping acceleration after gradually reducing the acceleration of the motor as the speed command for the inverter. 6.   6. The crane drive device according to claim 4, wherein the control unit issues a speed command for gradually increasing acceleration after the acceleration of the motor is stopped as the speed command for the inverter. 7.   4. The crane drive device according to claim 1, wherein the control unit performs a speed command for reducing acceleration as the speed command for the inverter. 5.   The said control part performs the stop command with respect to the said motor as the said speed command with respect to the said inverter, or performs the speed command which accelerates in the direction opposite to the running direction of the said traveling part. The crane drive device according to claim 1.   The crane driving device according to any one of claims 1 to 8, wherein the pair of driving units has an overload resistance value of current in each of the motors larger than the upper limit value. A drive device according to any one of claims 1 to 9,
A suspended body that suspends the load;
A pair of traveling parts having traveling wheels that travel on traveling paths provided on the left and right sides of the suspended body;
Crane with.

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