Transport vehicle

Abstract

A transport vehicle is provided with a holding device for holding articles, a lifting device for lifting the holding device, a control device (5), and a power supply unit (6) for receiving power from the outside and supplying power to at least the lifting device. The lifting device is provided with a lifting drive mechanism (40) for lifting and driving the holding device, and a restraining mechanism (41) for mechanically restraining the lifting operation of the holding device by the lifting drive mechanism (40). The voltage supplied from the power supply unit (6) to the lifting drive mechanism (40) is used as the target voltage, and the lower limit voltage required by the lifting drive mechanism (40) for maintaining the position of the holding device in the lifting direction is used as the required lower limit voltage. The control device (5) is provided with a voltage monitoring unit (51) that monitors a target voltage. When the target voltage is equal to or less than the determination threshold value, the control device (5) executes a preliminary restraint operation for operating the restraint mechanism (41).

Description

Technical Field

[0001] The invention relates to a conveying vehicle for conveying articles. Background Art

[0002] An example of such a transport vehicle is disclosed in Japanese Patent Application Laid-Open No. 2016-94263 (Patent Document 1). In the following description of the background art, the reference numerals and names in Patent Document 1 are cited in parentheses.

[0003] The ceiling transport vehicle (1) of Patent Document 1 comprises a support mechanism (23) for suspending and supporting a transport object (6) and a lifting and lowering operation mechanism (24) for raising and lowering the support mechanism (23). The lifting and lowering operation mechanism (24) comprises a winding body (28) for winding a winding belt (24a) connected to and supporting the support mechanism (23) at its end portion and a lifting and lowering motor (29) for rotationally driving the winding body (28), and is configured in the following manner: the winding body (28) is rotationally driven forward and reversely by the lifting and lowering motor (29) under the control of a motor driver, and the winding belt (24a) is wound and unwound, thereby causing the support mechanism (23) to be raised and lowered relative to the travel moving part (16).

[0004] That is, the lifting and lowering operation mechanism (24) is constructed in the following manner: by winding the winding belt (24a), a pair of conveying object support parts (32) are raised to the lifting height, and the conveying object (6) supported by the support mechanism (23) is raised to the supporting height; by releasing the winding belt (24a), the pair of conveying object support parts (32) are lowered to the lowering height, and the conveying object (6) supported by the support mechanism (23) is lowered to the transfer height. Summary of the invention

[0005] Here, during the travel of the ceiling transport vehicle (1), the support mechanism (23) and the transport object (6) are sometimes controlled to maintain the support height by the torque of the lifting motor (29). In such a case, if an abnormal power supply due to a power outage occurs, the torque of the lifting motor (29) cannot be maintained, and the winding belt may be released, the support mechanism (23) may be lowered, and the transport object (6) may fall. In order to prevent this situation, it is also possible to consider providing a brake on the lifting motor or the lifting operation mechanism (24).

[0006] However, after a power failure or other abnormality occurs, the brake is actuated, so that the support mechanism (23) and the conveyed object (6) are lowered to a certain extent. Therefore, in the recovery operation after the power failure or other abnormality is eliminated, there is a problem that the workload (manual) of the recovery operation is likely to increase, such as the need to return the support mechanism (23) to its original height.

[0007] Therefore, it is desired to realize a transport vehicle that can suppress the workload of recovery work after the abnormal power supply is resolved even when abnormal power supply due to a power outage or the like occurs.

[0008] The technology for solving the above-mentioned problems is as follows. A conveyor vehicle is a conveyor vehicle for conveying articles. It lies in the following points: have: A holding device, which holds the aforementioned items; A lifting device, which enables the aforementioned holding device to be lifted and lowered; Control devices; and a power supply unit that receives power from the outside and supplies the power to at least the lifting device; The lifting device comprises a lifting drive mechanism for lifting and lowering the holding device and a restraining mechanism for mechanically restraining the lifting and lowering movement of the holding device performed by the lifting drive mechanism. The voltage supplied from the power supply unit to the lifting drive mechanism is taken as the target voltage, and the lower limit voltage required by the lifting drive mechanism to maintain the position of the holding device in the lifting direction is taken as the required lower limit voltage. The control device comprises a voltage monitoring unit for monitoring the target voltage, and when the target voltage becomes below a determination threshold, performs a preliminary restraint action for activating the restraint mechanism, wherein the determination threshold is set to a value lower than the voltage in normal operation of the power supply unit and higher than the required lower limit voltage.

[0009] According to this structure, even if the voltage supplied to the lifting and lowering drive mechanism drops due to a power outage or a malfunction of the power supply unit, the lifting and lowering action of the holding device can be mechanically restrained by the restraint mechanism before the lifting and lowering drive mechanism cannot maintain the position of the holding device in the lifting direction due to the voltage drop. Therefore, even when a power outage or a malfunction of the power supply unit occurs, the holding device is prevented from being unintentionally lowered. Furthermore, when it is necessary to restore the position of the device in the lifting direction as the recovery process of the transport vehicle, the workload of the recovery process can be reduced.

[0010] Further features and advantages of the technology according to the present disclosure will become more apparent from the following description of illustrative and non-limiting embodiments described with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a top view of the article conveying equipment. Figure 2 It is a figure which shows the transfer operation. Figure 3 This is the front view of the transport vehicle. Figure 4 This is a block diagram showing the control structure of the transport vehicle. Figure 5 This is a block diagram showing a control structure of the transport vehicle according to the second embodiment. DETAILED DESCRIPTION

[0012] 1. First Implementation Method A first embodiment of a transport vehicle 1 is described based on the drawings. The transport vehicle 1 is configured to transport a container 8 having a predetermined shape while traveling along a travel path 10. Hereinafter, an example is given of a case where the transport vehicle 1 that receives power in a non-contact manner from a power supply line 12 arranged along the travel path 10 is applied to an article transport facility 100, and an embodiment of the transport vehicle 1 is described based on the drawings.

[0013] like Figure 1 As shown, the article transport facility 100 includes: a predetermined travel path 10 ; a transport vehicle 1 that travels along the travel path 10 to transport a container 8 ; and a plurality of transfer target locations 13 that are provided along the travel path 10 .

[0014] In addition, the article transport facility 100 includes a power supply line 12 (see Figure 3 ) and a power supply system of a power supply device (not shown) connected to the power supply line 12 and supplying AC current to the power supply line 12, using wireless power supply technology to supply driving power to the transport vehicle 1. The power supply line 12 is arranged along the travel path 10, and is arranged on both sides of the path width direction that is orthogonal to the path direction that is the direction along the travel path 10 with respect to the power receiving device 60. In addition, in order to suppress the decrease in power transmission efficiency or the overall stop of the equipment in the event of a failure, it is ideal that the power supply system is not only one system, but multiple systems are provided.

[0015] The travel path 10 is set at a position separated from the floor surface upward. In this example, the travel path 10 is formed using a track 11 provided near the ceiling. The transport vehicle 1 is configured as a so-called ceiling transport vehicle 1, and travels along the track 11. The transfer target location 13 is arranged below the travel path 10. The transport vehicle 1 is configured in a manner to transfer the container 8 between the transfer target location 13 by raising and lowering the container 8.

[0016] In this embodiment, the article conveying equipment 100 includes a plurality of conveying vehicles 1. Each of the plurality of conveying vehicles 1 is configured to receive a conveying instruction from a superior control device (not shown) of a unified management device and to perform a task corresponding to the conveying instruction. For example, the conveying instruction includes information on the conveying starting point and the conveying destination of the container 8. The conveying vehicle 1 that has received the conveying instruction conveys the container 8 from the conveying starting point to the conveying destination. The conveying starting point and the conveying destination include a transfer object portion 13.

[0017] As the container 8 handled by the article conveying device 100, there are various containers. In this example, the article conveying device 100 is used in a semiconductor manufacturing plant. Therefore, a substrate holding container 8 (so-called FOUP: Front Opening Unified Pod) that holds a substrate (wafer or panel, etc.) or an intermediate mask holding container 8 (so-called intermediate mask box) that holds an intermediate mask is a container 8. In this case, the conveying vehicle 1 conveys containers 8 such as substrate holding containers 8 or intermediate mask holding containers 8 along the travel path 10 between each process.

[0018] In this embodiment, the transfer target portion 13 includes a processing device 14 for processing the container 8 and a stage 15 disposed adjacent to the processing device 14. In this specification, the so-called "processing of the container 8" means processing of the object (substrate or intermediate mask) contained in the container 8. The transport vehicle 1 receives the container 8 that has been processed by the processing device 14 from the stage 15, or delivers the container 8 that has not been processed by the processing device 14 to the stage 15. In addition, the processing device 14 performs various processes such as thin film formation, photolithography, etching, etc.

[0019] like Figure 2 and Figure 3 As shown, the transport vehicle 1 includes a travel device 2 that travels on a track 11 and a storage portion 7 that stores a container 8 (article). In addition, the transport vehicle 1 includes: a holding device 3 that holds the container 8; a lifting device 4 that lifts the holding device 3; and a control device 5 (see Figure 4 and a power supply unit 6, which receives power supply from the outside and supplies power to at least the lifting device 4. The storage portion 7 includes a holding device 3 for holding articles and a lifting device 4 for lifting the holding device 3.

[0020] The travel device 2 is configured to move the entire transport vehicle 1 along the travel path 10 by traveling on the rail 11. In the present embodiment, the travel device 2 includes a plurality of travel wheels 20 that roll on the rail 11 and a travel drive mechanism 21 that drives at least a portion of the plurality of travel wheels 20. The travel drive mechanism 21 includes a travel drive motor 210 (for example, a servo motor) and a drive driver 211 (drive circuit) that controls the travel drive motor 210.

[0021] like Figure 4 As shown, the power supply unit 6 in this embodiment includes a power receiving device 60 that receives power from the power supply system, a DC conversion rectifier circuit 61 (for example, a PSB substrate, etc.), and a voltage adjustment DC-DC converter 62, thereby supplying power to various parts of the transport vehicle 1.

[0022] The power receiving device 60 includes a pickup coil 601 disposed on the transport vehicle 1 so as to face the power supply line 12 (see Figure 3 ) and a power receiving unit (not shown) formed on a wiring substrate inside the transport vehicle 1.

[0023] When the power supply system causes a high-frequency current to flow through the power supply line 12 as an induction line and generates a magnetic field around the power supply line 12, the pickup coil 601 of the power receiving device 60 generates an induced electromotive force by the alternating current flowing through the power supply line 12. That is, the power for driving the travel device 2, the lifting device 4, the holding device 3, and the control device 5 is supplied from the power supply line 12 to the power receiving device 60 of the power supply unit 6 in a non-contact manner. In addition, in the present embodiment, a configuration in which power is supplied from the power supply unit 6 to the travel device 2, the lifting device 4, the holding device 3, and the control device 5 is shown, but the present invention is not limited thereto, and as long as power is supplied from the power supply unit 6 to at least the lifting device 4, power may be supplied from another power supply to the travel device 2, the holding device 3, and the control device 5.

[0024] like Figure 2 As shown, the holding device 3 is a device that is freely movable and supports the article in a suspended state, and is provided inside the storage portion 7 .

[0025] The holding device 3 is configured to hold the container 8. The holding device 3 includes a holding body 30 suspended from the lifting device 4, a pair of holding bodies 31 supported by the holding body 30, and a holding drive mechanism 32 for driving the pair of holding bodies 31. The holding drive mechanism 32 includes a holding drive motor 320 (for example, a servo motor) and a drive driver 321 (drive circuit) for controlling the holding drive motor 320.

[0026] The holding device 3 in this embodiment uses a chuck unit that holds the container 8 by locking a pair of holding bodies 31 to a gripped portion (not shown) of the container 8, but is not limited to this configuration. As another configuration, for example, the holding device 3 may also be a configuration having a fork-type transfer unit, which has a fork that supports the container 8 and moves forward and backward. In addition, here, the advancing and retreating member that is a member that supports the supported object and moves forward and backward by the advancing and retreating device is referred to as a "fork", and the "fork" is not limited to a specific shape.

[0027] like Figure 4 As shown, the lifting device 4 includes: a lifting drive mechanism 40 that drives the holding device 3 to lift and lower; and a restraining mechanism 41 that mechanically restrains the lifting and lowering action of the holding device 3 performed by the lifting drive mechanism 40. The lifting drive mechanism 40 includes: a rotating body; a lifting belt 400 (an example of a wound member) that is wound around the rotating body so as to be wound and unwound freely; a lifting drive motor 401 (for example, a servo motor) that drives the rotating body to rotate; and a driving driver 402 (driving circuit) that controls the lifting drive motor 401.

[0028] The rotating body in this embodiment means a member that winds around the member to be wound, and examples thereof include a well-known rotating drum, etc. As an example of the member to be wound, a lifting belt is cited, but as long as it is a member wound around the rotating body of the lifting device 4, it is not particularly limited, and for example, a wire material, etc. may also be used.

[0029] The lifting drive motor 401 is provided with a restraint mechanism 41 for mechanically restraining the lifting motion of the holding device 3. The restraint mechanism 41 is configured to be capable of both restraining motion and restraint releasing motion. Examples of such restraint mechanism 41 include a lifting motor holding brake.

[0030] like Figure 2 As shown, the lifting device 4 is configured to lift the holding device 3 between the storage portion 7 and the transfer target portion 13 arranged below the travel path 10. The lifting belt 400 is connected to the holding device 3. The holding device 3 is configured such that the holding device 3 is lowered by releasing the lifting belt 400 from the rotating body while the holding device 3 is suspended by the lifting belt 400, and the holding device 3 is raised by winding the lifting belt 400 around the rotating body.

[0031] The storage section 7 is configured to be able to accommodate a container 8 to be transported. In the present embodiment, the storage section 7 is suspended and supported by the travel device 2 and is arranged below the rail 11. The storage section 7 is configured to be able to accommodate a container 8 held by the holding device 3. When the transport vehicle 1 transports the container 8 along the travel path 10, the container 8 is accommodated in the storage section 7.

[0032] like Figure 4 As shown, the control device 5 includes a controller 50 for controlling the overall movement of the transport vehicle 1 and a voltage monitoring unit 51 for monitoring the target voltage. As the controller 50, for example, an OPC (Object linking and embedding for Process Control) substrate can be used. In addition, the controller 50 is not limited to the case of controlling the overall movement of the transport vehicle 1, and can also be a configuration that only controls the lifting device 4. In addition, the so-called target voltage in this embodiment means the voltage supplied from the power supply unit 6 to the lifting drive mechanism 40.

[0033] The transport vehicle 1 switches between multiple power supply systems and continuously receives power supply to freely travel in the article transport facility 100. The article transport facility 100 is provided with a higher-level control device (not shown) that issues a transport command to the control device 5 of each transport vehicle 1 to transport articles.

[0034] The transport vehicle 1 drives autonomously based on the transport instruction. For example, at a predetermined transfer object location 13 (storage warehouse, etc.) containing semiconductor substrates, etc., after the holding device 3 is lowered by the lifting device 4 to hold the container 8 of the transport object, the holding device 3 is raised to accommodate the container 8 in the accommodation portion 7. Next, the transport vehicle 1 moves along the travel path 10 to another predetermined transfer object location 13, whereupon the holding device 3 is lowered by the lifting device 4 to unload the previously accommodated container 8. In this way, the transport vehicle 1 transports items between the predetermined transfer object locations 13. In addition, the superior control device selects the transport vehicle 1 in accordance with the transport starting point and the transport destination in such a way that the transport vehicle 1 supplied with power by each power supply system becomes within a predetermined number of receiving stations, and issues a transport instruction to the selected transport vehicle 1.

[0035] In the transport vehicle 1 involved in the present invention, the voltage supplied from the power supply unit 6 to the lifting drive mechanism 40 is set as the target voltage, and the lower limit voltage required by the lifting drive mechanism 40 to maintain the position of the lifting direction of the holding device 3 is set as the "required lower limit voltage". In more detail, the "required lower limit voltage" refers to the following concept: it includes not only the voltage value when the lifting drive mechanism 40 cannot maintain the position of the lifting direction of the holding device 3 due to an error in the drive driver 402 that controls the lifting drive motor 401, but also the voltage value when the lifting drive motor 401 has insufficient torque due to insufficient power.

[0036] like Figure 4As shown, the control device 5 has a voltage monitoring unit 51 for monitoring the target voltage as described above. Moreover, it is configured in the following manner: when the voltage monitoring unit 51 detects that the target voltage becomes below the "determination threshold", the controller 50 performs a preparatory restraint action (an action to mechanically restrain the lifting action) to operate the restraint mechanism 41 of the lifting drive motor 401, wherein the "determination threshold" is set to a value lower than the voltage in the normal operation of the power supply unit 6 (this voltage is referred to as the normal voltage) and higher than the required lower limit voltage. For example, when the normal voltage is 320V and the required lower limit voltage is 200V, and the determination threshold is set to 250V, when the target voltage becomes below 250V, the controller 50 operates the restraint mechanism 41 and stops the lifting drive motor 401 to prevent the holding device 3 from unintentionally descending. In addition, when the normal voltage has an amplitude (amplitude), its lower limit voltage value is interpreted as the normal voltage.

[0037] In addition, the power supply unit 6 may also include a power storage device for temporarily storing electric power, and the power storage device is configured to supply the voltage of the power storage device to the lifting drive mechanism 40. In the present embodiment, a power storage device is provided to supplement insufficient electric power when the DC conversion rectifier circuit 61 (PSB (Power Supply Board, power supply board) substrate, etc.) is insufficient in the driving action or lifting action of the transport vehicle 1. As such a power storage device, for example, a capacitor (for example, a capacitor for regenerative charging, etc.) or a small storage battery can be cited.

[0038] In addition, when the controller 50 maintains the position of the holding device 3 in the lifting direction and the object voltage is greater than the judgment threshold, and performs a position holding action of maintaining the position of the holding device 3 in the lifting direction by controlling the driving force of the lifting drive motor 401, the required lower limit voltage becomes the lower limit voltage that can perform the position holding action by the lifting drive motor 401, or the voltage required for the normal operation of the driver 402 for driving the lifting drive motor 401.

[0039] In addition, the transport vehicle 1 may be provided with an "article height detection sensor" for detecting that the position of the holding device 3 or the container 8 held by the holding device 3 in the lifting direction is lower than a predetermined reference height, for example, in the storage portion 7. In this case, during the detection period of the article height detection sensor, the transport vehicle 1 cannot be restored to the normal operation mode unless the container 8 is returned to the normal position. Therefore, in the case of a conventional transport vehicle, the operation of returning the container 8 to the normal position becomes necessary.

[0040] On the other hand, according to this configuration, before the lifting drive mechanism 40 cannot maintain the position of the holding device 3 in the lifting direction due to the decrease in the voltage supplied to the lifting drive mechanism 40, that is, before the holding device 3 is lowered and the position of the container 8 in the lifting direction becomes a position lower than the predetermined reference height, the lifting action of the holding device 3 can be mechanically restrained by the restraining mechanism 41. Therefore, even in the event of a power outage or a malfunction of the power supply unit 6, the holding device 3 is prevented from being unintentionally lowered, and the position of the container 8 in the lifting direction is maintained at the predetermined reference height, so that the article height detection sensor does not perform detection, and therefore, the operation of returning the container 8 to the height is not required.

[0041] 2. Second Implementation Method Next, use Figure 5 The second embodiment of the transport vehicle 1 is described. In this embodiment, the controller 50 for controlling the overall operation of the transport vehicle 1 and the voltage monitoring unit 51 for monitoring the target voltage are integrally configured, which is different from the first embodiment described above. In the following, the transport vehicle 1 involved in this embodiment is described mainly with the differences from the first embodiment described above. In addition, the points not particularly described are the same as those of the first embodiment described above.

[0042] In the first embodiment, the controller 50 for controlling the overall operation of the transport vehicle 1 and the voltage monitoring unit 51 for monitoring the target voltage are separately provided. However, in the present embodiment, the controller 50 is configured to control the overall operation of the transport vehicle 1 and monitor the target voltage.

[0043] In the present embodiment, the controller 50 is connected to the driving driver 211 of the travel driving motor 210, the driving driver 402 of the lifting driving motor 401, and the driving driver 321 of the holding driving motor 320 via the Local Area Network (LAN 9), and is configured to monitor the voltage of each driver 211, 321, 402 via the LAN 9. When the controller 50 detects that the target voltage becomes less than the determination threshold, the controller 50 performs a preparatory restraint action to activate the restraint mechanism 41 of the lifting driving motor 401.

[0044] In addition, the configuration disclosed in each of the above-mentioned embodiments can also be combined with the configuration disclosed in other embodiments and applied as long as no contradiction occurs. Regarding other configurations, the embodiments disclosed in this specification are only illustrative in all points. Therefore, various changes can be appropriately made without departing from the scope of the present disclosure.

[0045] 3. Summary of this Implementation Hereinafter, the embodiments related to the transport vehicle described above will be summarized and described below.

[0046] A conveyor vehicle is a conveyor vehicle for conveying articles. have: A holding device, which holds the aforementioned items; A lifting device, which enables the aforementioned holding device to be lifted and lowered; Control devices; and a power supply unit that receives power from the outside and supplies the power to at least the lifting device; The lifting device comprises a lifting drive mechanism for lifting and lowering the holding device and a restraining mechanism for mechanically restraining the lifting and lowering movement of the holding device performed by the lifting drive mechanism. The voltage supplied from the power supply unit to the lifting drive mechanism is taken as the target voltage, and the lower limit voltage required by the lifting drive mechanism to maintain the position of the holding device in the lifting direction is taken as the required lower limit voltage. The control device comprises a voltage monitoring unit for monitoring the target voltage, and when the target voltage becomes below a determination threshold, performs a preliminary restraint action for activating the restraint mechanism, wherein the determination threshold is set to a value lower than the voltage in normal operation of the power supply unit and higher than the required lower limit voltage.

[0047] According to this configuration, even when the voltage supplied to the lifting drive mechanism drops due to a power outage or a malfunction of the power supply unit, the lifting and lowering action of the holding device can be mechanically restrained by the restraint mechanism before the lifting drive mechanism cannot maintain the position of the holding device in the lifting direction due to the voltage drop. Therefore, even when a power outage or a malfunction of the power supply unit occurs, the holding device is prevented from being lowered unintentionally. In addition, when the position of the lifting and lowering direction of the holding device must be restored as a recovery process of the transport vehicle, the workload of the recovery process can be reduced.

[0048] Here, preferably, the power supply unit includes a power storage device for temporarily storing electric power. The voltage of the power storage device is supplied to the lifting and lowering drive mechanism.

[0049] According to this configuration, even in the event of a power outage or a malfunction of the power supply unit, the power storage device can compensate for the momentary power shortage and avoid a sharp drop in the voltage supplied to the lifting drive mechanism. Therefore, the reliability of the execution of the preliminary restraint action by the control device can be improved.

[0050] In addition, it is suitable that the lifting drive mechanism includes a rotating body, a wound member that is wound around the rotating body and can be freely wound and unwound, and a lifting drive motor that rotationally drives the rotating body, and is configured in the following manner: when the holding device is suspended by the wound member, the holding device is lowered by the wound member being unwound from the rotating body, and the holding device is raised by the wound member being wound around the rotating body. The aforementioned lifting drive motor is a servo motor. The control device performs a position holding action to hold the position of the holding device in the lifting direction by controlling the driving force of the lifting drive motor when the position of the holding device in the lifting direction is held and the target voltage is greater than the determination threshold. The required lower limit voltage is a lower limit voltage that enables the position holding operation by the lifting drive motor, or a voltage required for normal operation of a driver for driving the lifting drive motor.

[0051] According to this configuration, when the voltage supplied from the power supply unit to the lifting drive mechanism is normal, the position holding action in the lifting direction of the holding device is performed by controlling the driving force of the lifting drive motor, thereby eliminating the need to frequently switch between the constraint and the release of the constraint by the constraint mechanism, and making it easy and quick to perform the lifting action of the holding device. On the other hand, when the voltage supplied to the lifting drive mechanism drops due to a power outage or a malfunction of the power supply unit, it is difficult to properly perform the position holding action by controlling the driving force of the lifting drive motor. However, according to this configuration, as described above, before the lifting drive mechanism cannot maintain the position of the holding device in the lifting direction due to the drop in the voltage supplied to the lifting drive mechanism, the lifting action of the holding device can be mechanically constrained by the constraint mechanism. Therefore, even in the event of a power outage or a malfunction of the power supply unit, the holding device is prevented from being unintentionally lowered. Industrial Applicability

[0052] The technology according to the present disclosure can be utilized in a transport vehicle that transports articles by traveling along a travel path. Description of Reference Numerals

[0053] 1: Transport vehicle 2: Driving device 20: Driving wheel 21: Travel drive mechanism 210: Travel drive motor 211: Driver for driving 3: Holding device 30: Maintain the main body 31: Keep the body 32: Maintain drive mechanism 320: Keep driving motor 321: Driver for driving 4: Lifting device 40: Lifting drive mechanism 400: Lifting belt (wrap parts) 401: Lifting drive motor 402: Driver for driving 41: Constraints 5: Control device 50: Controller 51: Voltage monitoring unit 6: Power supply unit 60: Power receiving device 601: Pickup coil 61: Rectifier circuit for DC conversion 62: DC-DC converter for voltage regulation 7: Accommodation 8: Container (item) 9: LAN 10: Driving path 11: Track 12: Power supply line 13: Transfer target area 14: Processing device 15: Loading table 100: Article conveying equipment.

Claims

1. A transport vehicle, which is a transport vehicle for transporting articles. The transport vehicle has the following features: have: a holding device that holds the article; A lifting device that lifts and lowers the holding device; Control devices; and a power supply unit that receives power from the outside and supplies the power to at least the lifting device, The lifting device includes a lifting drive mechanism for lifting and lowering the holding device and a restraining mechanism for mechanically restraining the lifting and lowering movement of the holding device performed by the lifting drive mechanism. The voltage supplied from the power supply unit to the lifting drive mechanism is used as the target voltage, and the lower limit voltage required by the lifting drive mechanism to maintain the position of the holding device in the lifting direction is used as the required lower limit voltage. The control device includes a voltage monitoring unit that monitors the target voltage, and performs a preliminary restraint action to activate the restraint mechanism when the target voltage becomes below a determination threshold, wherein the determination threshold is set to a value lower than the voltage in normal operation of the power supply unit and higher than the required lower limit voltage.

2. The transport vehicle according to claim 1, wherein: The power supply unit includes a power storage device for temporarily storing electric power. The voltage of the power storage device is supplied to the lifting and lowering drive mechanism.

3. The transport vehicle according to claim 1 or 2, wherein: The lifting and lowering drive mechanism includes a rotating body, a wound member that can be wound around and released freely, and a lifting and lowering drive motor that rotationally drives the rotating body, and is configured in such a manner that, in a state where the holding device is suspended by the wound member, the holding device is lowered by releasing the wound member from the rotating body, and the holding device is raised by winding the wound member around the rotating body. The lifting drive motor is a servo motor, The control device performs a position holding operation to hold the position of the holding device in the lifting direction by controlling the driving force of the lifting drive motor when the position of the holding device in the lifting direction is held and the target voltage is greater than the determination threshold value. The required lower limit voltage is a lower limit voltage that enables the position holding operation by the lifting drive motor, or a voltage required for normal operation of a driver for driving the lifting drive motor.

Images