Transport vehicle

Abstract

A transport vehicle (100) capable of appropriately detecting an obstacle by means of an obstacle sensor in a configuration comprising a fork, wherein: a fork (1) is disposed so as to protrude from a lifting / lowering device (2) toward a rear side (D2); a vehicle body (3) includes a main body part (31) for supporting a travel drive device, and a pair of leg parts (32) disposed so as to protrude from the main body part (31) toward the rear side (D2) on both sides in the width direction with respect to a lifting / lowering trajectory of the fork (1); a first obstacle sensor (91) is disposed on at least one leg part among the pair of leg parts (32); and a control device (10) executes travel avoidance control for controlling the lifting / lowering device (2) such that the fork (1) is positioned within a sensor avoidance range when causing the travel drive device to drive a drive wheel (41) such that the vehicle body (3) moves at least to the rear side (D2), with the sensor avoidance range being the range of the vertical position of the fork (1) in which the fork (1) and a pallet (P) supported by the fork (1) are above a detection surface (S1) of the first obstacle sensor (91).

Description

Transport Vehicle

[0001] The present invention relates to a transport vehicle.

[0002] Patent Document 1 below discloses a transport vehicle (1) including a fork (60) for supporting a pallet, a lifting device (70) for lifting and lowering the fork (60), and an obstacle sensor (21F) for detecting an obstacle intersecting with a detection surface (21F3) along the horizontal direction. Note that the reference numerals shown in parentheses in the description of the background art are those of Patent Document 1.

[0003] In the transport vehicle (1) of Patent Document 1, when traveling such that the fork (60) is positioned on the front side in the traveling direction, the obstacle sensor (21F) detects an obstacle existing on the front side in the traveling direction.

[0004] Japanese Unexamined Patent Application Publication No. 2019-105995

[0005] However, in the transport vehicle (1) of Patent Document 1, depending on the position of the fork (60), the detection surface (21F3) of the obstacle sensor (21F) may interfere with the fork (60) or the pallet supported by the fork (60), and there may be cases where an obstacle cannot be appropriately detected.

[0006] Therefore, in a configuration including a fork, it is desired to realize a transport vehicle capable of appropriately detecting an obstacle by an obstacle sensor.

[0007] In view of the above, the characteristic configuration of the transport vehicle is a transport vehicle comprising: forks for supporting a pallet; a lifting device for raising and lowering the forks; a plurality of wheels including a drive wheel; a driving device for driving the drive wheel; a vehicle body supporting the lifting device, the plurality of wheels, and the driving device; and a control device for controlling the lifting device and the driving device, wherein a specific direction along the horizontal plane is defined as the front-rear direction, one side of the front-rear direction is defined as the front side, the other side of the front-rear direction is defined as the rear side, and a direction along the horizontal plane that is perpendicular to the front-rear direction is defined as the width direction, the forks are arranged to protrude from the lifting device toward the rear side, the vehicle body comprises a main body that supports the driving device, and a pair of legs arranged on both sides in the width direction with respect to the lifting trajectory of the forks so as to protrude from the main body toward the rear side, and further comprises a first obstacle sensor for detecting obstacles intersecting a detection surface along the horizontal direction, the first obstacle sensor is arranged on at least one of the pair of legs. The control device defines the range of vertical positions of the fork, such that the fork and the pallet supported by the fork are above the detection surface of the first obstacle sensor, as the sensor avoidance range. The control device then performs avoidance control during travel, controlling the lifting device so that the fork is located within the sensor avoidance range when the travel drive device drives the drive wheels so that the vehicle body moves at least to the rear.

[0008] With this feature configuration, when the vehicle body moves at least to the rear due to the avoidance control during driving, the forks are positioned within the sensor avoidance range. This prevents the detection surface of the first obstacle sensor from interfering with the forks or the pallet supported by the forks. Therefore, in a configuration with forks, obstacles can be appropriately detected by the first obstacle sensor.

[0009] Perspective view of the transport vehicle according to the embodiment Bottom view of the transport vehicle according to the embodiment Plan cross-sectional view of the transport vehicle according to the embodiment Side view of the transport vehicle according to the embodiment Plan cross-sectional view showing the configuration of the travel drive device and rotation detection device Perspective view showing the first obstacle sensor etc. Perspective view showing the second obstacle sensor etc.

[0010] In the following description, the transport vehicle 100 according to the embodiment will be explained with reference to the drawings.

[0011] As shown in Figures 1 and 2, the transport vehicle 100 comprises a fork 1, a lifting device 2, a vehicle body 3, a plurality of wheels 4, and a driving device 5.

[0012] In the following description, a specific direction along the horizontal plane will be referred to as the "front-rear direction D". One side of the front-rear direction D will be referred to as the "front side D1", and the other side of the front-rear direction D will be referred to as the "rear side D2". Furthermore, a direction along the horizontal plane that is perpendicular to the front-rear direction D will be referred to as the "width direction W". In this application, the "vertical direction" refers to the vertical direction when the transport vehicle 100 is positioned on a horizontal plane.

[0013] The fork 1 is configured to support the pallet P. The fork 1 is positioned to protrude from the lifting device 2 toward the rear D2. In this embodiment, a pair of forks 1 are arranged side by side with a gap between them in the width direction W. As the pallet P, various existing pallets commonly used in the logistics industry can be used.

[0014] As shown in Figures 1 and 3, the lifting device 2 is a device for raising and lowering the fork 1. In this embodiment, the lifting device 2 comprises a pair of lifting rails 21, a pair of lifting rollers 22, a pair of roller support members 23, a fork connecting member 24, a lifting member 25, a lifting drive device 26, and a pair of chains 27.

[0015] Each of the pair of lifting rails 21 is formed to extend along the vertical direction. The pair of lifting rails 21 are arranged side by side with a gap between them in the width direction W.

[0016] Each of the pair of lifting rollers 22 is configured to roll along the lifting rail 21. In this embodiment, each of the pair of lifting rollers 22 is configured to rotate freely around a rotation axis along the width direction W. Each of the pair of lifting rollers 22 is arranged to roll on a pair of rolling surfaces on the lifting rail 21 that face each other in the front-rear direction D.

[0017] Each of the pair of roller support members 23 is a member that rotatably supports the lifting roller 22. In this embodiment, each of the pair of roller support members 23 is formed in a plate shape perpendicular to the width direction W.

[0018] The fork connecting member 24 is the member to which the forks 1 are connected. A pair of roller support members 23 are fixed to the fork connecting member 24. In this embodiment, the fork connecting member 24 is formed in the shape of a plate perpendicular to the front-rear direction D.

[0019] The lifting member 25 is a member that is raised and lowered by a lifting drive device 26 via a pair of chains 27. The lifting member 25 is connected to a fork connecting member 24. Therefore, as the lifting member 25 moves up and down, the fork 1 moves up and down via the fork connecting member 24. In this embodiment, the lifting member 25 is formed in the shape of a plate perpendicular to the vertical direction.

[0020] As shown in Figure 1, the lifting drive device 26 is a device that raises and lowers a lifting member 25 via a pair of chains 27. In this embodiment, the lifting drive device 26 comprises a pair of sprockets (not shown) around which the pair of chains 27 are wound, and a lifting drive source (not shown) that rotates the pair of sprockets.

[0021] In this embodiment, one end of a pair of chains 27 is connected to a lifting member 25. The other end of the pair of chains 27 is connected to a pair of forks 1, a pair of lifting rollers 22, a pair of roller support members 23, a fork connecting member 24, and a counterweight 28 (see Figure 4) that balances the lifting member 25.

[0022] As shown in Figures 3 and 4, the vehicle body 3 is configured to support the lifting device 2, a plurality of wheels 4, and the driving device 5. The vehicle body 3 comprises a main body 31 and a pair of legs 32. In this embodiment, the vehicle body 3 further comprises a cover 33 (see also Figure 1).

[0023] The main body 31 is configured to support the travel drive unit 5. In this embodiment, the main body 31 includes a swivel support section 311, a pair of lower rail support sections 312, and an upper rail support section 313.

[0024] As shown in Figure 3, the swivel support section 311 is configured to support the travel drive unit 5 so that it can rotatably support it around a swivel axis C1 that is aligned in the vertical direction.

[0025] The pair of lower rail support sections 312 are configured to support the lower parts of the pair of lifting rails 21. The pair of lower rail support sections 312 are arranged separately on both sides in the width direction W relative to the swivel support section 311. In this embodiment, each of the pair of lower rail support sections 312 is provided with a fixed wall 314.

[0026] As shown in Figure 4, each of the pair of fixed walls 314 is formed to extend along the vertical direction. A lifting rail 21 is fixed to each of the pair of fixed walls 314. In this embodiment, each of the pair of fixed walls 314 is formed in the shape of a plate perpendicular to the front-rear direction D. Each of the pair of fixed walls 314 is fixed to the lifting rail 21 in a state where it is in contact with the lower part of the lifting rail 21 from the front side D1.

[0027] The upper rail support portion 313 is configured to support the upper parts of the pair of lifting rails 21. In this embodiment, the upper rail support portion 313 is formed in the shape of a plate perpendicular to the vertical direction. The upper rail support portion 313 is fixed to the pair of lifting rails 21 in a state where it is in contact with the upper ends of the pair of lifting rails 21 from above.

[0028] As shown in Figure 3, the pair of legs 32 are positioned on both sides in the width direction W with respect to the lifting trajectory of the fork 1. The pair of legs 32 are formed to protrude from the main body 31 toward the rear side D2. In this embodiment, each of the pair of legs 32 has a hollow structure.

[0029] As shown in Figure 1, the cover 33 is formed to cover the main body 31. In this embodiment, the cover 33 is formed so as not to interfere with the lifting trajectories of the pair of forks 1, as well as the lifting trajectories of the pair of roller support members 23, fork connecting member 24, and lifting member 25 of the lifting device 2.

[0030] As shown in Figure 2, the plurality of wheels 4 include drive wheels 41. In this embodiment, the plurality of wheels 4 include a pair of drive wheels 41 and two pairs of driven wheels 42.

[0031] In the following explanation, the direction along the rotation axis of the drive wheel 41 will be referred to as the "axial direction L". Furthermore, the direction perpendicular to the axial direction L when viewed from above and below will be referred to as the "travel direction T".

[0032] The drive wheels 41 are among the multiple wheels 4 and are driven by the travel drive unit 5. The drive wheels 41 are supported by the travel drive unit 5. In this embodiment, a pair of drive wheels 41 are arranged coaxially. The pair of drive wheels 41 are arranged side by side with a gap between them in the axial direction L.

[0033] The driven wheels 42 are among the multiple wheels 4 that are not driven by the drive unit including the travel drive unit 5. In this embodiment, a pair of driven wheels 42 are rotatably supported on each of the pair of legs 32. The pair of driven wheels 42 supported on each of the pair of legs 32 are arranged coaxially so as to be spaced apart from each other in the width direction W. In the example shown in Figure 2, the pair of driven wheels 42 are supported on each of the pair of legs 32 in the portion D2 behind the lifting device 2.

[0034] In this embodiment, the difference in rotation of the pair of drive wheels 41 causes the travel drive unit 5, to which the pair of drive wheels 41 are supported, to rotate around the pivot axis C1. When the travel drive unit 5 is rotated at a 90° angle, the pair of drive wheels 41 are driven to rotate, causing the transport vehicle 100 to rotate around the vehicle pivot axis C2 which is aligned vertically. In this embodiment, the vehicle pivot axis C2 is positioned so as to pass through an intermediate position in the width direction W between the pair of driven wheels 42 supported by one leg portion 32 and the pair of driven wheels 42 supported by the other leg portion 32 (a position equally spaced from the pair of driven wheels 42) on the rotation axis of the two pairs of driven wheels 42. The "rotation angle of the travel drive unit 5" is the angle at which the rotation axis of the drive wheels 41 intersects the width direction W.

[0035] The travel drive unit 5 is a device that drives the drive wheels 41. As shown in Figure 5, in this embodiment, the travel drive unit 5 includes a pair of first support members 51, a second support member 52, a third support member 53, and a pair of travel drive sources 54.

[0036] The pair of first support members 51 are supported by the swivel support portion 311 so as to be able to rotatably around the swivel axis C1. The pair of first support members 51 are arranged separately on both sides of the travel direction T with respect to the swivel axis C1. In this embodiment, each of the pair of first support members 51 is formed in the shape of a plate perpendicular to the travel direction T. The pair of first support members 51 are arranged to extend downward from the swivel support portion 311.

[0037] The second support member 52 extends along the travel direction T so as to pass through the pivot axis C1. The second support member 52 is positioned to connect the pair of first support members 51.

[0038] The third support member 53 is configured to support a pair of travel drive sources 54. The third support member 53 is positioned between the pair of first support members 51 in the travel direction T. The third support member 53 is supported by the pair of first support members 51. In this embodiment, the third support member 53 includes a pair of first wall portions 531 and a pair of second wall portions 532.

[0039] Each of the pair of first wall portions 531 is formed in a plate shape perpendicular to the travel direction T. The pair of first wall portions 531 are arranged to face each other with a gap between them in the travel direction T. Each of the pair of first wall portions 531 is connected to a pair of first support members 51.

[0040] Each of the pair of second wall portions 532 is formed in a plate shape perpendicular to the axial direction L. The pair of second wall portions 532 are arranged to face each other with a gap between them in the axial direction L. Each of the pair of second wall portions 532 supports a pair of drive sources 54. In this embodiment, a pair of drive wheels 41 are arranged separately on both sides of the pair of second wall portions 532 in the axial direction L.

[0041] Each of the pair of drive sources 54 is a drive source for a pair of drive wheels 41. The pair of drive sources 54 are configured to drive the pair of drive wheels 41 independently of each other. The pair of drive sources 54 are spaced apart from each other in the axial direction L. Each of the pair of drive sources 54 is supported by a pair of second wall portions 532. In this embodiment, each of the pair of drive sources 54 is an electric motor.

[0042] As shown in Figure 6, the transport vehicle 100 is equipped with a first obstacle sensor 91. The first obstacle sensor 91 is a sensor that detects obstacles intersecting a first detection surface S1 that is aligned horizontally. The first obstacle sensor 91 is located on at least one of a pair of legs 32. In this embodiment, the first obstacle sensor 91 is located on each of the pair of legs 32. The first detection surface S1 is a "detection surface" that indicates an area in which obstacles can be detected by the first obstacle sensor 91.

[0043] In addition, in the present embodiment, the first obstacle sensor 91 is disposed so as to protrude from at least one of the upper surfaces of the pair of legs 32. In the illustrated example, each of the pair of first obstacle sensors 91 is disposed inside the leg 32 so as to protrude upward from the upper surface thereof through a through hole that vertically penetrates the upper surface of the hollow leg 32 (see also FIG. 4). Note that, for example, a configuration in which the first obstacle sensor 91 is installed on the upper surface of the leg 32 is also included in the configuration in which the "first obstacle sensor 91 is disposed so as to protrude from the upper surface of the leg 32".

[0044] As shown in FIG. 4, in the present embodiment, the first obstacle sensor 91 is disposed so as to overlap with the lifting device 2 in a widthwise view along the width direction W. In the illustrated example, the first obstacle sensor 91 is disposed so as to overlap with the lifting locus of the fork connecting member 24 of the lifting device 2 in a widthwise view along the width direction W. Here, regarding the arrangement of the two elements, "overlapping in a specific direction view" means that when a virtual straight line parallel to the line-of-sight direction is moved in each direction orthogonal to the virtual straight line, there is at least a partial region where the virtual straight line intersects both of the two elements.

[0045] As shown in FIG. 4, the transport vehicle 100 includes a control device 10. The control device 10 is a device that controls the lifting device 2 and the traveling drive device 5. In the present embodiment, the control device 10 is fixed to the vehicle body 3 so as to be located on the front side D1 with respect to the pair of lifting rails 21.

[0046] When the control device 10 drives the drive wheels 41 of the traveling drive device 5 so that the vehicle body moves at least to the rear side D₂, the control device 10 executes avoidance control during traveling to control the lifting device 2 so that the fork 1 is located within the sensor avoidance range. Here, the "sensor avoidance range" is a range of the vertical position of the fork 1 in which the fork 1 and the pallet P supported by the fork 1 are above the first detection surface S1 of the first obstacle sensor 91. FIG. 4 shows a state in which the avoidance control during traveling is being executed.

[0047] In this embodiment, when the fork 1 does not support the pallet P, the control device 10 does not execute the avoidance control during traveling. Further, when the control device 10 drives the drive wheels 41 of the traveling drive device 5 so that the vehicle body 3 moves to the front side D1, the control device 10 does not execute the avoidance control during traveling. When the control device 10 does not execute the avoidance control during traveling, the fork is arranged at the reference height. The reference height is set, for example, to the height of the lower limit of the lifting range of the fork 1. In this embodiment, in the avoidance control during traveling, the fork 1 is raised from the reference height to a height at which the fork 1 is located within the sensor avoidance range. The reference height is the height at which the fork 1 is arranged above or below the first detection surface S1 of the first obstacle sensor 91 and the pallet P supported by the fork 1 intersects the first detection surface S1. Therefore, when the fork 1 does not support the pallet P, the first detection surface S1 of the first obstacle sensor 91 does not interfere with the fork 1 even if the avoidance control during traveling is not executed.

[0048] As shown in FIG. 7, in this embodiment, the transport vehicle 100 further includes a second obstacle sensor 92 and a measurement range sensor 93.

[0049] The second obstacle sensor 92 is a sensor that detects obstacles existing around the vehicle body S. The second obstacle sensor 92 is arranged on the front side D1 with respect to the main body portion 31 of the vehicle body 3. In this embodiment, the second obstacle sensor 92 is configured to detect an obstacle that intersects the second detection surface S2 along the horizontal direction. Further, in this embodiment, the second obstacle sensor 92 is fixed to the vehicle body 3 so as to protrude from the surface facing the front side D1 of the cover 33. In the example shown in FIG. 7, a slit along the width direction W is formed in the cover 93 so that the second detection surface S2 of the second obstacle sensor 92 does not interfere with the cover 33. The second detection surface S2 is a detection surface indicating a region where an obstacle can be detected by the second obstacle sensor 92.

[0050] The range sensor 93 is a sensor used in SLAM (Simultaneous Localization and Mapping), a technology for automated guided vehicles such as the transport vehicle 100 to travel automatically. As shown in Figure 4, in this embodiment, the range sensor 93 is positioned on the upper rail support portion 313 of the vehicle body 3 so as to protrude upward from the upper surface of the cover 33 through a through hole that penetrates the upper surface in the vertical direction.

[0051] As shown in Figure 6, in this embodiment, the transport vehicle 100 further includes a pair of first pallet detection sensors 94, a pair of second pallet detection sensors 95, a pair of third pallet detection sensors 96, a pair of first collision detection sensors 97, and a second collision detection sensor 98.

[0052] The pair of first pallet detection sensors 94 are a "pair of pallet detection sensors" that detect whether or not a pallet P is located within the region between the pair of legs 32 in the width direction W. Each of the pair of first pallet detection sensors 94 is positioned at the rear end D2 of the pair of legs 32.

[0053] In this embodiment, each of the pair of first pallet detection sensors 94 is a laser distance sensor that emits a laser beam B in a straight line. Each of the pair of first pallet detection sensors 94 is positioned inside the hollow leg portion 32 and emits the laser beam B toward the rear D2 through a through hole that penetrates the surface of the leg portion 32 facing the rear D2 in the front-rear direction D (see also Figure 4). In this embodiment, the control device 10 determines that the pallet P is located within the region between the pair of leg portions 32 in the width direction W if the pallet P is located between the pair of laser beams B in the width direction W without contact with the pair of laser beams B emitted by the pair of first pallet detection sensors 94.

[0054] The pair of second pallet detection sensors 95 are sensors that detect whether or not the pallet P is properly supported by the pair of forks 1. Each of the pair of second pallet detection sensors 95 is positioned on the pair of forks 1. In this embodiment, each of the pair of second pallet detection sensors 95 is positioned at the front end D1 of the pair of forks 1.

[0055] Furthermore, in this embodiment, each of the pair of second pallet detection sensors 95 includes a first dog 951 that is pressed downward by the pallet P and swings when the pallet P is supported in the appropriate position by the pair of forks 1, and a first microswitch 952 that detects the swing of the first dog 951 (see also Figure 4). The control device 10 determines that the pallet P is properly supported by the pair of forks 1 without tilting when both of the pair of first dogs 951 swing downward and the pair of first microswitches 952 detect their swing.

[0056] The pair of third pallet detection sensors 96 are sensors that detect whether or not the pallet P is properly supported by the pair of forks 1. Each of the pair of third pallet detection sensors 96 is positioned on the pair of forks 1. In this embodiment, each of the pair of third pallet detection sensors 96 is positioned at the front end D1 of the pair of forks 1, above the pair of second pallet detection sensors 95.

[0057] Furthermore, in this embodiment, each of the pair of third pallet detection sensors 96 includes a second dog 961 that is pressed forward D1 by the pallet P and swings when the pallet P is supported in an appropriate position by the pair of forks 1, and a second microswitch 962 that detects the swing of the second dog 961 (see also Figure 4). The control device 10 determines that the pallet P is supported by the pair of forks 1 in an appropriate position in the front-rear direction D when both of the pair of second dogs 961 swing forward D1 and the pair of second microswitches 962 detect their swing.

[0058] The pair of first collision detection sensors 97 are sensors for detecting collisions. Each of the pair of first collision detection sensors 97 is positioned at the tip of each of the pair of forks 1. In this embodiment, each of the pair of first collision detection sensors 97 includes a pressure-sensitive switch.

[0059] The second collision detection sensor 98 is a sensor for detecting collisions. The second collision detection sensor 98 is positioned to surround the vehicle body 3. In this embodiment, the second collision detection sensor 98 is positioned to cover the lower ends of the surfaces of the pair of legs 32 that face opposite each other in the width direction W, and the surface of the cover 33 that faces the front side D1, so as to form a U shape in plan view. In this embodiment, the second collision detection sensor 98 also includes a pressure-sensitive switch.

[0060] As shown in Figure 5, in this embodiment, the transport vehicle 100 further includes a rotation detection device 6 and a rotation position sensor 7.

[0061] The rotation detection device 6 is a device that detects the rotation of the drive wheels 41. In this embodiment, the transport vehicle 100 is equipped with a pair of rotation detection devices 6 in order to detect the rotation of the pair of drive wheels 41.

[0062] The rotation detection device 6 is supported by the drive unit 5. The rotation detection device 6 includes a driven roller 61 and a rotation sensor 62. The driven roller 61 is a roller that rotates in conjunction with the rotation of the drive wheel 41. The driven roller 61 is positioned so as to be in contact with the outer circumferential surface of the drive wheel 41. The rotation sensor 62 is a sensor that detects the rotation of the driven roller 61. In this embodiment, the rotation sensor 62 is an encoder.

[0063] In this embodiment, a pair of rotation sensors 62 are arranged to detect the rotation of a pair of driven rollers 61. In this embodiment, the travel drive source 54 is equipped with a sensor such as an encoder that detects the rotation of the output element of the travel drive source 54. The rotation sensors 62 are provided independently of the sensors mounted on the travel drive source 54. With this configuration, the travel state of the transport vehicle 100 can be monitored in a dual manner, making it easier to improve the accuracy and safety of the travel control of the transport vehicle 100.

[0064] In this embodiment, the rotation detection device 6 further comprises a pair of fixed members 63. Each of the pair of fixed members 63 is fixed to a pair of second wall portions 532. A driven roller 61 and a rotation sensor 62 are supported on each of the pair of fixed members 63. In this embodiment, the driven roller 61 and the rotation sensor 62 are arranged axially L apart with respect to the fixed members 63.

[0065] Furthermore, in this embodiment, the rotation detection device 6 is positioned inward from the outer edge of the turning trajectory of the drive wheel 41 when the travel drive unit 5 turns around the turning axis C1, when viewed from above. (See the dashed line in Figure 5.)

[0066] In this embodiment, the control device 10 changes the area of ​​the first detection surface S1 of the pair of first obstacle sensors 91 and the second detection surface S2 of the second obstacle sensor 92 based on the rotation of the pair of driven rollers 61 detected by the pair of rotation sensors 62. For example, when the control device 10 drives the drive wheels 41 to the drive unit 5 so that the vehicle body 3 moves toward the rear side D2 on at least one side in the width direction W, the control device 10 moves the first detection surface S1 of the pair of first obstacle sensors 91 toward one side in the width direction W.

[0067] The swivel position sensor 7 is a sensor that detects whether the swivel angle of the travel drive unit 5 with respect to the width direction W is within a set angle range including 90°. The set angle range is set to, for example, 90 ± 20°. In this embodiment, a pair of detectable parts 71 are provided that extend from a pair of first support members 51 so as to be spaced apart from each other in the travel direction T. The pair of detectable parts 71 swivel in conjunction with the swivel of the travel drive unit 5. In this embodiment, the control device 10 determines that the swivel angle of the travel drive unit 5 is within the above set angle range when the swivel position sensor 7 detects either of the pair of detectable parts 71. In this embodiment, the swivel position sensor 7 is supported by the lower rail support part 312 of the main body part 31.

[0068] [Other Embodiments] (1) In the above embodiment, a configuration in which the first obstacle sensor 91 is placed on each of the pair of legs 32 was described as an example. However, the invention is not limited to such a configuration, and a configuration in which the first obstacle sensor 91 is placed on only one of the pair of legs 32 is also possible.

[0069] (2) In the above embodiment, a configuration in which the first obstacle sensor 91 is arranged to protrude from the upper surface of the leg portion 32 was described as an example. However, the configuration is not limited to such a configuration, and for example, the first obstacle sensor 91 may be arranged to protrude from the surface of the leg portion 32 facing the width direction W.

[0070] (3) In the above embodiment, a configuration was described as in which the first obstacle sensor 91 is arranged so as to overlap with the lifting trajectory of the fork connecting member 24 of the lifting device 2 when viewed in the width direction W. However, the configuration is not limited to such a configuration, and for example, the first obstacle sensor 91 may be arranged so as to overlap with the lifting rail 21 of the lifting device 2 when viewed in the width direction W. Alternatively, the first obstacle sensor 91 may be arranged so as to overlap with the main body 31 of the vehicle body 3 when viewed in the width direction W.

[0071] (4) In the above embodiment, a configuration was described in which the travel drive unit 5 rotates around the pivot axis C1 by the difference in rotation of a pair of drive wheels 41. However, the configuration is not limited to such a configuration, and for example, a configuration in which a drive unit is provided to rotate the travel drive unit 5 around the pivot axis C1 may also be used. In this configuration, there may be only one drive wheel 41.

[0072] (5) In the above embodiment, a configuration in which multiple wheels 4 include drive wheels 41 and driven wheels 42 was described as an example. However, the system is not limited to such a configuration, and for example, all wheels 4 may be drive wheels 41.

[0073] (6) In the above embodiment, a configuration in which a pair of forks 1 are arranged side by side with a gap between them in the width direction W was described as an example. However, the configuration is not limited to such a configuration, and a configuration with one fork 1 or three or more forks 1 is also possible.

[0074] (7) The configurations disclosed in each of the embodiments described above can be applied in combination with configurations disclosed in other embodiments, as long as no inconsistencies arise. With regard to other configurations, the embodiments disclosed herein are merely illustrative in all respects. Therefore, various modifications can be made as appropriate, without departing from the spirit of this disclosure.

[0075] [Summary of this embodiment] The following describes the outline of the transport vehicle described above.

[0076] The transport vehicle comprises: forks for supporting a pallet; a lifting device for raising and lowering the forks; a plurality of wheels including drive wheels; a drive device for driving the drive wheels; a vehicle body supporting the lifting device, the plurality of wheels, and the drive device; and a control device for controlling the lifting device and the drive device, wherein a specific direction along a horizontal plane is defined as the front-rear direction, one side of the front-rear direction is defined as the front, the other side of the front-rear direction is defined as the rear, and a direction along the horizontal plane that is perpendicular to the front-rear direction is defined as the width direction; the forks are arranged to protrude from the lifting device toward the rear; the vehicle body comprises a main body supporting the drive device; and a pair of legs arranged on both sides in the width direction with respect to the lifting trajectory of the forks, so as to protrude from the main body toward the rear; and further comprises a first obstacle sensor for detecting obstacles intersecting a detection surface along the horizontal direction, the first obstacle sensor being located on at least one of the pair of legs. The control device defines the range of vertical positions of the fork such that the fork and the pallet supported by the fork are above the detection surface of the first obstacle sensor as the sensor avoidance range, and when the control device drives the drive wheel to the drive unit so that the vehicle body moves at least to the rear, it performs driving avoidance control to control the lifting device so that the fork is located within the sensor avoidance range.

[0077] With this configuration, when the vehicle body moves at least to the rear due to the avoidance control during driving, the forks are positioned within the sensor avoidance range. This prevents the detection surface of the first obstacle sensor from interfering with the forks or the pallet supported by the forks. Therefore, in a configuration with forks, obstacles can be appropriately detected by the first obstacle sensor.

[0078] In this case, it is preferable that the control device does not perform the avoidance control during travel if the fork is not supporting the pallet.

[0079] With this configuration, if the forks are not supporting a pallet, the detection surface of the first obstacle sensor will not interfere with the pallet, thus avoiding unnecessary fork raising and lowering movements caused by the avoidance control during travel.

[0080] Furthermore, it is preferable that the control device does not perform the avoidance control during driving when it causes the drive drive unit to drive the drive wheels so that the vehicle body moves forward.

[0081] With this configuration, when the vehicle body moves forward, it is unnecessary for the first obstacle sensor, which is located on at least one of the pair of legs that protrude backward from the main body of the vehicle body, to detect obstacles. Therefore, unnecessary fork raising and lowering movements caused by avoidance control during driving can be avoided.

[0082] Furthermore, it is preferable that the first obstacle sensor is positioned to protrude from the upper surface of at least one of the pair of legs.

[0083] This configuration prevents the detection surface of the first obstacle sensor from interfering with the legs. Furthermore, it avoids increasing the dimensions of the transport vehicle in the front-to-back or width direction due to the installation of the first obstacle sensor.

[0084] Furthermore, it is preferable that the first obstacle sensor is positioned on each of the pair of legs so as to overlap with the lifting device when viewed in the width direction along the width direction.

[0085] This configuration allows the first obstacle sensor to be positioned away from the front of the fork. Therefore, it is easier to avoid damage to the first obstacle sensor due to contact with the pallet, such as when the pallet's position shifts.

[0086] Furthermore, the vehicle is further equipped with a second obstacle sensor for detecting obstacles present around the vehicle body, and it is preferable that the second obstacle sensor is positioned on the front side of the main body.

[0087] With this configuration, even if the detection surface of the first obstacle sensor interferes with the main body of the vehicle, the second obstacle sensor can appropriately detect obstacles located in front of the vehicle.

[0088] Furthermore, it is preferable to further include a pair of pallet detection sensors, each positioned at the rear end of the pair of legs, which detect whether or not the pallet is located within the area between the pair of legs in the width direction.

[0089] This configuration allows for the detection of whether the positional relationship of the pallet being supported by the forks relative to the transport vehicle is appropriate. Therefore, it facilitates proper support of the pallet by the forks.

[0090] The technology disclosed herein can be used in transport vehicles.

[0091] 100: Transport vehicle 1: Fork 2: Lifting device 3: Body 31: Main body 32: Legs 4: Wheels 41: Drive wheels 5: Driving device 91: First obstacle sensor 92: Second obstacle sensor 94: First pallet detection sensor (pallet detection sensor) 10: Control device P: Pallet S1: First detection surface (detection surface) D: Front-rear direction D1: Front side D2: Rear side W: Width direction

Claims

1. A transport vehicle comprising: forks for supporting a pallet; a lifting device for raising and lowering the forks; a plurality of wheels including a drive wheel; a drive device for driving the drive wheel; a vehicle body supporting the lifting device, the plurality of wheels, and the drive device; and a control device for controlling the lifting device and the drive device, wherein a specific direction along a horizontal plane is defined as the front-rear direction, one side of the front-rear direction is defined as the front, the other side of the front-rear direction is defined as the rear, and a direction along the horizontal plane that is perpendicular to the front-rear direction is defined as the width direction; the forks are arranged to protrude from the lifting device toward the rear; the vehicle body comprises a main body supporting the drive device; and a pair of legs arranged on both sides in the width direction with respect to the lifting trajectory of the forks, so as to protrude from the main body toward the rear; and further comprising a first obstacle sensor for detecting obstacles intersecting a detection surface along the horizontal direction, the first obstacle sensor being located on at least one of the pair of legs. A transport vehicle, wherein the sensor avoidance range is defined as the range of vertical positions of the forks such that the forks and the pallet supported by the forks are above the detection surface of the first obstacle sensor, and the control device performs travel avoidance control, controlling the lifting device so that the forks are located within the sensor avoidance range when the travel drive device drives the drive wheels so that the vehicle body moves at least to the rear.

2. The transport vehicle according to claim 1, wherein the control device does not perform the avoidance control during travel when the fork is not supporting the pallet.

3. The transport vehicle according to claim 1, wherein the control device does not perform the avoidance control during travel when the drive drive unit drives the drive wheels so that the vehicle body moves forward.

4. The transport vehicle according to any one of claims 1 to 3, wherein the first obstacle sensor is arranged to protrude from the upper surface of at least one of the pair of legs.

5. The transport vehicle according to any one of claims 1 to 3, wherein the first obstacle sensor is arranged on each of the pair of legs so as to overlap with the lifting device in a widthwise view along the width direction.

6. The transport vehicle according to any one of claims 1 to 3, further comprising a second obstacle sensor for detecting obstacles present around the vehicle body, wherein the second obstacle sensor is positioned on the front side relative to the main body.

7. The transport vehicle according to any one of claims 1 to 3, further comprising a pair of pallet detection sensors, each positioned at the rear end of a pair of legs, for detecting whether the pallet is located within the region between the pair of legs in the width direction.

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