Load rotation device

Abstract

To provide a suspended load turning apparatus capable of reliably limiting turning speed of suspended load even when disturbance such as wind occurs.SOLUTION: There is provided a suspended load turning apparatus 10 comprising a flywheel 11, a flywheel rotating electric motor 12 for driving the flywheel 11, a gimbal 13 for pivotally supporting the flywheel 11, and a gimbal inclining electric motor 14 for driving the gimbal 13, the apparatus causing suspended load 50 to turn by a gyroidal effect generated when the gimbal 13 is inclined while rotating the flywheel 11. The apparatus is provided with turning speed controlling means 15 for suppressing increase in the turning speed of the suspended load 50 by, when an inclination torque T of the gimbal inclining electric motor 14 exceeds a limiting value Tr, holding input current to the gimbal inclining electric motor 14 with the value at that time, and suspending the inclination by the gimbal inclining electric motor 14.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a load rotating device for rotating a load such as a crane. [Background technology]

[0002] In cargo handling operations using cranes, the load is rotated (horizontally rotated) until it is in the specified orientation, and then lowered to the desired location. Rotating a load is usually done by an assistant standing nearby to assist the load (pulling or pushing the load). However, when the load is large or heavy, multiple assistants must work together while communicating with each other, which creates the problem of significantly reducing work efficiency. In addition, if a worker is assisting the load nearby, there is a risk of an accident, such as the worker falling over if hit by the rotating load.

[0003] In view of this situation, a device (load rotation device) that mechanically rotates a suspended load without human power has been developed, and this device is used in cargo handling operations. As shown in FIG. 1 of Patent Document 1, a known load rotation device incorporates a gyro device (see reference number 10 in the figure). As shown in FIG. 2 of Patent Document 1, the gyro device includes a disk-shaped member called a "flywheel" (see reference number 10a in the figure) and a member called a "gimbal" that supports the flywheel (see reference number 11 in the figure). This type of load rotation device is interposed between the hook of a crane and a suspended load, and rotates the load by the gyro effect generated by tilting (tilting) the gimbal while rotating the flywheel at high speed.

[0004] However, in the above-mentioned load rotation device, while the gimbal continues to tilt in one direction, the gyro effect continues to be exerted from the flywheel to the gimbal, and the rotation speed of the load continues to increase. For this reason, if the load is light, the rotation speed of the load may become too fast, which may cause danger. In this regard, load rotation devices that feedback control the rotation speed of the load have been proposed. For example, paragraphs 0022-0032 and Figure 1 of Patent Document 2 show that in a load attitude control device (load rotation device) that uses the gyro effect to rotate a load, the load angular velocity φ' M (the rotation speed of the suspended load) is read by the gyro sensor 101, and the angular velocity command value φ' and the suspended load angular velocity φ' M It is described that the torque controller 206 controls the torque so that the deviation between the torque and the torque is zero. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 63-074891 [Patent Document 2] JP 2014-133600 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in a load rotation device that performs feedback control of the rotation speed of a load, the correction process for the rotation speed of the load follows behind, so when a disturbance such as wind occurs, the load may continue to rotate at a rotation speed that exceeds the limit value until the correction process catches up. Also, not only is it necessary to provide a sensor (such as a gyro sensor) that detects the rotation speed of the load, but it is also necessary to perform complex control, such as various calculations.

[0007] The present invention has been made to solve the above problems, and provides a load rotation device that can reliably limit the rotation speed of a suspended load even when disturbances such as wind occur. Another object of the present invention is to limit the rotation speed of a suspended load using a simple method that does not use a separate sensor to detect the rotation speed of the suspended load. [Means for solving the problem]

[0008] The above issues are: A flywheel and a flywheel rotating motor that drives the flywheel to rotate; A gimbal that supports the flywheel; A gimbal tilting motor that drives the gimbal to tilt; Equipped with A load rotation device that rotates a load by using a gyro effect that occurs when a gimbal is tilted while a flywheel is rotated, The torque T of the gimbal tilt motor is limited to T r a rotation speed limiting means for limiting the rotation speed of the load (means the angular velocity of the load) by stopping the tilting by the gimbal tilting motor when the input current to the gimbal tilting motor exceeds the preset value, This is solved by providing

[0009] As already mentioned, in a load rotation device utilizing the gyroscopic effect, while the gimbal continues to tilt in one direction, the rotation speed of the load continues to increase due to the gyroscopic effect exerted on the gimbal by the flywheel. Therefore, when the load starts to rotate, a gyroscopic effect is generated by the rotation of the load, and a torque is applied to the output shaft of the gimbal tilting motor in the opposite direction to the direction in which the output shaft is rotating (tilting). In the following, this torque in the opposite direction is referred to as "torque generated by the rotation of the load" and may be expressed as "torque T'" using the symbol "T'". In addition, the torque that the gimbal tilting motor outputs to the output shaft to tilt the gimbal is referred to as "tilting torque" and may be expressed as "tilting torque T" using the symbol "T".

[0010] The torque T' generated by the rotation of the load increases as the rotation speed of the load increases. When viewed from the perspective of the tilt torque T of the gimbal tilting motor, torque T' becomes a resistance force (resistance torque). For this reason, as the rotation speed of the load increases, a larger resistance torque (torque T') is applied to the output shaft of the gimbal tilting motor, and the tilt torque T of the gimbal tilting motor increases. Conversely, as the rotation speed of the load slows, the resistance torque (torque T') applied to the gimbal tilting motor decreases, and a smaller tilt torque T of the gimbal tilting motor is required. In this way, the rotation speed of the load is directly reflected in the tilt torque T of the gimbal tilting motor.

[0011] In this regard, the load rotation device of the present invention has a limit value T r When the load rotation speed exceeds the upper limit (when the load rotation speed is about to exceed the upper limit), the tilting by the gimbal tilting motor is stopped, so that the load rotation speed does not increase any further (the rotation speed is limited). By limiting the load rotation speed based on the tilt torque T, which directly reflects the load rotation speed, it is possible to quickly and reliably limit the load rotation speed when the load rotation speed is about to exceed the upper limit, even if there is a disturbance such as wind. Also, it is possible to limit the load rotation speed in a simple manner without the need for complex calculations.

[0012] In the load rotation device of the present invention, the above series of operations (operations for limiting the rotation speed of the load when the tilt torque T exceeds the limit value Tr) are executed by a rotation speed limiting means. An example of this rotation speed limiting means is a current-limiting torque limiter. An inverter device that controls the frequency of the AC current input to the gimbal tilting motor is usually interposed between the gimbal tilting motor (AC motor) and the power source, and the current-limiting torque limiter can be realized by control using this inverter device. Therefore, in the load rotation device of the present invention, there is no need to provide a separate sensor (such as a gyro sensor) for detecting the rotation speed of the load. This makes it possible to simplify the configuration of the load rotation device.

[0013] Preferably, the limit value T r A load rotating device is provided that is equipped with a limit value adjustment means for adjusting the limit value.

[0014] Preferably, the tilt torque T of the gimbal tilt motor is set to a limit value T r When the load rotation speed falls below this limit, the restriction on the rotation speed of the load by the rotation speed limiting means is released, the input current to the gimbal tilting motor increases, and tilting of the gimbal tilting motor resumes. Effect of the Invention

[0015] As described above, the present invention makes it possible to provide a load rotation device that can reliably limit the rotation speed of a suspended load even when disturbances such as wind occur. It also makes it possible to limit the rotation speed of a suspended load using a simple method that does not require a separate sensor to detect the rotation speed of the suspended load. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view showing a state in which a load of a crane is rotated using a load rotation device. [Diagram 2] FIG. 4 is a flow chart showing an example of a load rotation operation by the load rotation device. [Diagram 3] 13 is a graph showing the relationship between the power supply time to the gimbal tilting motor and the rotation speed of the load when a limit value Tr is changed in a load rotation device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] A preferred embodiment of the load slewing device will be described in more detail with reference to the drawings. Fig. 1 is a perspective view showing a state in which a load 50 of a crane is slewing using a load slewing device 10. The enlarged circled portion of Fig. 1 shows the internal structure of the load slewing device 10 in a see-through state.

[0018] As shown in Fig. 1, the load slewing device 10 rotates a load 50 suspended from a crane hook 60 or the like in the direction of arrow A1 around a vertical axis L1. The load slewing device 10 is provided in a location where it can transmit the rotation force to the load 50 when it rotates around the vertical axis L1. In the example shown in Fig. 1, the load slewing device 10 is interposed between the load 50 and the crane hook 60, and is attached above the load 50, but even if it is attached below the load 50, the load 50 can still be rotated.

[0019] The load rotation device 10 contains a flywheel 11, a flywheel rotation motor 12, a gimbal 13, a gimbal tilt motor 14, and a rotation speed limiting means 15 in a housing 16. The flywheel 11 is disk-shaped, and its center is journaled by the gimbal 13 in a state in which it can rotate around an axis L2 in the direction of an arrow A2. The flywheel rotation motor 12 drives the flywheel 11 to rotate around the axis L2. The gimbal 13 is in the form of a frame surrounding the flywheel 11, and both ends are journaled in a state in which it can tilt around an axis L3 in the direction of an arrow A3. The axis L3, which is the tilt center of the gimbal 13, and the axis L2, which is the rotation center of the flywheel 11, are not parallel to each other (intersect) and are usually perpendicular to each other. The gimbal tilting motor 14 drives the gimbal 13 to tilt about the axis L3. The rotation speed limiting means 15 limits the rotation speed of the load 50 (angular velocity of rotation of the load 50).

[0020] In the load rotation device 10 of this embodiment, both the flywheel rotation motor 12 and the gimbal tilt motor 14 are electric motors. An inverter device (not shown) that controls the frequency of the AC current input to the gimbal tilt motor 14 is connected to the electric motor (AC motor) that constitutes the gimbal tilt motor 14, and this inverter device is equipped with a current-limiting torque limiter. This torque limiter functions as a rotation speed limiting means 15, as described later. In a non-operating state in which no current is input to either electric motor (the flywheel rotation motor 12 and the gimbal tilt motor 14), the flywheel 11 is in a state in which it can freely rotate around the axis L2, and the gimbal 13 is in a state in which it can freely tilt around the axis L3. In this non-operating state, the flywheel 11, the gimbal 13, etc. are balanced so that the flywheel 11 stands vertically (the axis L2, which is the center of rotation of the flywheel 11, lies horizontally).

[0021] When the flywheel rotation motor 12 is driven (current input to the flywheel rotation motor 12 is started) from the non-operating state, the flywheel 11 starts to rotate around the axis L2 (rotate in the direction of the arrow A2). When the gimbal tilting motor 14 is driven (current input to the gimbal tilting motor 14 is started), the gimbal 13 starts to tilt around the axis L3 (tilt in the direction of the arrow A3). In this way, when the gimbal 13 is tilted while the flywheel 11 is rotating, a gyro effect is exerted from the flywheel 11 to the gimbal 13, and a gyro moment is generated in the housing 16 of the load rotation device 10 around the vertical axis L1. This gyro moment causes the load rotation device 10 to rotate around the vertical axis L1 (rotate in the direction of the arrow A1). Since the load 50 is suspended below the load slewing device 10, when the load slewing device 10 rotates about the vertical axis L1, the load 50 also rotates about the vertical axis L1 (rotates in the direction of arrow A3).

[0022] The direction in which the load 50 rotates can be reversed by reversing the direction in which the flywheel 11 is rotated or the direction in which the gimbal 13 is tilted. When the load 50 has rotated to the desired direction, the rotation by the load rotation device 10 is stopped, and the rotation of the load 50 is stopped. The load rotation device 10 of this embodiment can be operated by a remote controller 17.

[0023] As described above, the load rotation device 10 rotates the load 50 by the gyro effect that occurs when the gimbal 13 is tilted while the flywheel 11 is rotating. However, while the gimbal 13 continues to tilt, the gyro effect continues to be exerted from the flywheel 11 to the gimbal 13, and the rotation speed of the load 50 continues to increase. For this reason, unless the rotation speed of the load 50 is limited, the rotation speed of the load 50 may become too fast, which may cause danger.

[0024] In this regard, in the load rotation device 10, the rotation speed limiting means 15 (torque limiter) is used to limit the increase in the rotation speed of the load 50. The rotation speed limiting means 15 (torque limiter) is configured to limit the increase in the rotation speed of the load 50 when the tilt torque T of the gimbal tilting motor 14 (the torque with which the gimbal tilting motor 14 tilts the gimbal 13 around the axis L3) reaches a predetermined limit value (T r ), the input current to the gimbal tilting motor 14 is held at the value at that time, and tilting by the gimbal tilting motor is stopped.

[0025] That is, when the load 50 is rotating, a torque T' is applied to the output shaft of the gimbal tilting motor 14 in a direction opposite to the direction in which the output shaft is rotating (tilting) (the direction of the tilting torque T) due to the gyro effect caused by the rotation of the load 50, and the tilting torque T of the gimbal tilting motor 14 increases. In other words, the rotation speed of the load 50 is directly reflected in the tilting torque T of the gimbal tilting motor 14. For this reason, the tilting torque T of the gimbal tilting motor 14 is an index of the rotation speed of the load 50. Therefore, by restricting the cymbal tilting motor 14, it is possible to restrict an increase in the rotation speed of the load 50.

[0026] FIG. 2 shows an example of a flow diagram of the rotation operation of the load 50 by the load rotation device 10. The rotation of the flywheel 11 is assumed to have already started at a stage prior to step S1 in FIG. 2. As shown in FIG. 2, when the rotation operation of the load 50 starts (step S1), the tilt of the gimbal 13 starts (step S2). Specifically, current input to the gimbal tilting motor 14 starts, and the current is increased. Then, the gimbal 13 gradually starts to tilt to one side from the initial position (standing vertically), and the load 50 starts to rotate in the direction of the arrow A1 (FIG. 1) due to the gyro effect caused by the rotation of the flywheel 11. As the tilt angle of the gimbal 13 increases, the rotation speed of the load 50 (angular velocity of rotation of the load 50) gradually accelerates.

[0027] In this way, when the gimbal 13 is tilted and the load 50 is rotating, if a rotation stop operation is performed by the remote controller 17 or the like ("YES" in step S3), the current input to the gimbal tilting motor 14 is stopped (step S7). This releases the gimbal 13 from being restrained by the gimbal tilting motor 14, and the gimbal 13 is now in a state where it can freely tilt in the direction of arrow A3 (FIG. 1). Therefore, the tilt of the gimbal 13 to one side is stopped, and thereafter, due to the gyro effect of the load 50 rotating by inertia, the gimbal 13 begins to tilt in the opposite direction (the side returning to the initial position), and the rotation of the load 50 is stopped. This ends the rotation operation of the load 50 (step S8).

[0028] On the other hand, if the gimbal 13 continues to tilt without performing a rotation stop operation ("NO" in step S3), the rotation speed of the load 50 continues to increase, and the tilt torque T of the gimbal tilting motor 14 increases beyond the limit value T r ("NO" in step S4). On the other hand, the tilt torque T of the gimbal tilt motor 14 increases until it reaches the limit value T r ("YES" in step S4), the tilting of the gimbal 13 is stopped (step S5). Specifically, the input current to the gimbal-tilting motor 14 is maintained at the value at that time (the current-carrying state at that time is maintained). When the tilting torque T of the gimbal-tilting motor 14 balances with the torque T' (FIG. 1) due to the gyro effect caused by the rotation of the suspended load 50, the tilting of the gimbal 13 is stopped.

[0029] When the tilt of the gimbal 13 is stopped, the gyro effect caused by the rotation of the flywheel 11 is no longer exerted on the load 50, and the increase in the rotation speed of the load 50 stops. Even if the tilt of the gimbal 13 is stopped, the load 50 continues to rotate due to inertia, but the rotation speed gradually decreases due to resistance such as friction. When the tilt torque T of the gimbal tilting motor 14 reaches the limit value T r While the tilt torque T of the gimbal tilt motor 14 is greater than the limit value T rWhen the difference becomes smaller than , the tilting of the gimbal 13 starts again ("YES" in step S6).

[0030] As described above, by limiting the rotation speed of the load 50 using a method for limiting the tilt torque T of the gimbal tilting motor 14, the rotation speed of the load 50 can be quickly limited when necessary. Therefore, even when a disturbance such as wind occurs, an increase in the rotation speed can be reliably suppressed so that the rotation speed does not exceed the upper limit. In addition, there is no need to perform complex calculations, and the rotation speed of the load 50 can be limited in a simple manner. Furthermore, there is no need to provide a separate sensor (such as a gyro sensor) for detecting the rotation speed of the load 50. Therefore, the configuration of the load rotation device 10 can be simplified.

[0031] Furthermore, as shown in step S6 of FIG. 2, when the tilt torque T of the gimbal tilt motor 14 reaches the limit value T r By configuring the gimbal tilting motor 14 to resume tilting when the load angle becomes smaller than the upper limit, it is possible to continue rotating the load 50 at the rotation speed just before it exceeds the upper limit, and it is also possible to improve the efficiency of loading and unloading operations, such as by rotating the load 50 to the desired orientation in a short period of time.

[0032] Incidentally, in the load rotating device 10, as can be seen from the execution of the process of step S4 in FIG. 2, the limit value T r The maximum value of the rotation speed (maximum angular velocity) of the load 50 changes depending on the load rotation device 10. r 1 is a graph showing the relationship between the power supply time to the gimbal tilt motor 14 and the rotation speed of the load 50 when the limit value T r is set to 100% of the rated torque of the gimbal tilt motor 14, the curve B is r is set to 70% of the rated torque of the gimbal tilt motor 14, the curve C is r is set to 50% of the rated torque of the gimbal tilt motor 14, the curve D is ris set to a value that is 30% of the rated torque of the gimbal tilt motor 14. r If you set a high value, the maximum rotation speed (maximum angular velocity) of the load 50 will be high, and conversely, the limit value T r When is set to a low value, the maximum value of the rotation speed (maximum angular velocity) of the load 50 becomes high. The graph in Fig. 3 was obtained by numerical calculation, but it has been confirmed that a result close to this can be obtained by actual measurement.

[0033] In consideration of such characteristics, the load rotation device 10 is provided with a limit value T r It is preferable to provide a limit value adjustment means (not shown) for adjusting the limit value T. This makes it possible to adjust the maximum value (maximum angular velocity) of the rotation speed of the load 50. The maximum value (maximum angular velocity) of the rotation speed of the load 50 also varies depending on the load (moment of inertia of rotation) of the load. When the load 50 is a light load, the limit value T r If the load 50 is a heavy load, the limit value T r In this way, the limit value T is set higher according to the load of the suspended load 50. r It also becomes possible to adjust the

[0034] In other words, the limit value T r may be a value that cannot be changed from a single predetermined value, but various loads are assumed for the load 50, ranging from light loads with a small moment of inertia in the rotation direction to heavy loads with a large moment of inertia. In other words, a light load is more likely to have a faster rotation speed than a heavy load, so the limit value T is set assuming a heavy load. r If the limit value T is set, when the load 50 is switched to a lighter (smaller) load, the circumferential speed (rotation speed) of the load 50 may become slower than necessary. r By providing a limit value adjustment means 15 (torque limiter) that adjusts the rotation speed of the suspended load 50, it is possible to increase the rotation speed of the suspended load 50 within a range that does not reach the critical speed.

[0035] The limit value adjustment means adjusts the limit value T r The control value T is adjusted stepwise from among a number of predetermined values. r Alternatively, the limit value T r The limit value adjusting means may be one that continuously adjusts the rotation speed of the load 50. Examples of the operating portion of the limit value adjusting means include various devices such as a button, a switch, a dial, a lever, and a touch panel. These operating portions may be provided on a remote controller 17 (FIG. 1). This allows the worker 70 to manually adjust the rotation speed of the load 50. [Explanation of symbols]

[0036] 10. Load rotating device 11 Flywheel 12 Flywheel rotation motor 13. Gimbal 14 Gimbal tilt motor 15 Turning speed limiting means 16 Case 17 Remote Controller 50 Hanging load 60 Hook 70 Worker A1 Rotation direction of the load A2 Flywheel rotation direction A3 Gimbal tilt direction L1 Vertical axis around which the load rotates L2: The axis around which the flywheel rotates L3 Gimbal tilt center axis

Claims

1. A flywheel and a flywheel rotating motor that drives the flywheel to rotate; A gimbal that supports the flywheel; A gimbal tilting motor that drives the gimbal to tilt; Equipped with A load rotation device that rotates a load by using a gyro effect that occurs when a gimbal is tilted while a flywheel is rotated, A rotation speed limiting means is provided, which is a current-limiting torque limiter and limits the rotation speed of the load. When the gimbal tilt angle is increased while the flywheel is rotating, the rotation speed of the load accelerates. When the load is rotating and the rotation stop operation is performed, the current input to the gimbal tilt motor is stopped, and the rotation of the load is stopped. If no turning stop operation is performed, When the tilt torque T of the gimbal tilting motor exceeds a predetermined limit value T r , the rotation speed control means maintains the input current to the gimbal tilting motor at the value at that time, and the tilting by the gimbal tilting motor is stopped. When the tilt torque T of the gimbal tilting motor falls below the limit value T r , the limit on the rotation speed of the load by the rotation speed limiting means is released, the input current to the gimbal tilting motor increases, and tilting of the gimbal tilting motor resumes. A load rotating device characterized by the above.

2. Limit value T ｒ 2. The load rotating device according to claim 1, further comprising a limit value adjusting means for adjusting the limit value.

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