Transport vehicles and transport equipment

Abstract

To provide a transport vehicle having excellent transport efficiency when transporting an article while rotating around a circular route having at least a partial arc-shaped section while maintaining an orientation of a vehicle body.SOLUTION: A transport vehicle (1) includes a vehicle body (2), a drive unit (3), and a coupling device (4) that couples the vehicle body (2) and the drive unit (3). The drive unit (3) includes wheels, a travel drive source that drives and rotates the wheels, and a steering device that turns the wheels around a steering axis (Xs). The coupling device (4) includes a mounting portion (41) that is attached to the vehicle body (2), and an adjustment mechanism that can change a reference direction (R) around the steering axis (Xs) with respect to a front-rear direction (L) of the vehicle body (2) by changing a mounting attitude of the mounting portion (41) relative to the vehicle body (2).SELECTED DRAWING: Figure 6

Description

Technical Field

[0006] , ,

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

Background Art

[0002] For example, in factories, logistics facilities, etc., transport vehicles are used to directly transport articles or tow carts on which articles are placed. An example of such a transport vehicle is disclosed in Japanese Patent Application Laid-Open No. 2005-297809 (Patent Document 1).

[0003] The transport vehicle (trolley towing vehicle 100) of Patent Document 1 includes a vehicle body (vehicle body 1) and a drive unit (drive wheels 2, traveling motor 5, drive wheel rotation motor 6), and these vehicle body and drive unit are usually connected via a connecting device having a fixed posture with respect to both the vehicle body and the drive unit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] <\ In Patent Document 1, as a steering device for turning the wheels (drive wheels 2), a device including a motor for wheel rotation (drive wheel rotation motor 6) and a speed reduction gear mechanism is exemplified. However, depending on the specifications of the transport vehicle, the maximum steering angle of the wheels may be limited to a certain angle less than ±360°. And in such a case, for example, when trying to turn a circular path having an arc-shaped section at least partially while maintaining the orientation of the vehicle body, the transport vehicle may have to be stopped halfway along the circular path and the steering angle of the drive unit may have to be significantly changed. Patent Document 1 does not describe such problems and their solutions at all.

[0006] Therefore, there is a need for a transport vehicle that offers superior transport efficiency when transporting goods while maintaining the orientation of the vehicle body along a circular route that includes, for example, at least a portion of an arc-shaped section. [Means for solving the problem]

[0007] The transport vehicle related to this disclosure is A transport vehicle comprising a vehicle body, a drive unit, and a coupling device for connecting the vehicle body and the drive unit, The drive unit comprises a wheel, a drive source for rotating the wheel, and a steering device for rotating the wheel around a steering axis along the vertical direction. The steering device is configured to be able to rotate in the direction of travel, which is perpendicular to the rotation axis of the wheels when viewed from above, within a range of ±θ° around the steering axis with respect to a predetermined reference direction (where θ is a predetermined value less than 360). The coupling device comprises a mounting portion attached to the vehicle body, and an adjustment mechanism that allows the reference direction to be changed around the steering axis with respect to the longitudinal direction of the vehicle body by changing the mounting position of the mounting portion to the vehicle body.

[0008] With this configuration, when a transport vehicle travels along a circular path that has, for example, at least part of an arc-shaped section without changing the orientation of the vehicle body, the mounting position of the mounting part to the vehicle body can be changed using the adjustment mechanism, and the reference direction can be biased in advance towards the side that will rotate the drive unit while traveling through the arc-shaped section. As a result, even if the maximum steering angle of the drive unit (wheels) by the steering device is limited to less than 360° on both the left and right sides, a wide range of arc-shaped sections can be secured in which the transport vehicle can travel continuously while gradually changing the steering angle of the drive unit. In other words, the number of times the transport vehicle needs to stop in the middle of an arc-shaped section to change the steering angle of the drive unit can be reduced. Therefore, the transport efficiency of the transport vehicle can be increased.

[0009] Further features and advantages of the technology relating to this disclosure will become clearer from the following description of exemplary and non-limiting embodiments, with reference to the drawings. [Brief explanation of the drawing]

[0010] [Figure 1] Schematic diagram of the conveying equipment of the embodiment [Figure 2] Side view of the transport vehicle [Figure 3] Bottom view of the transport vehicle [Figure 4] Diagram showing the steering range under standard specifications. [Figure 5] This diagram shows the electrical connection between the power supply and the drive unit. [Figure 6] A diagram showing the steering range when the reference direction is perpendicular to the longitudinal direction of the vehicle body. [Figure 7] A schematic diagram showing an example of an adjustment mechanism. [Modes for carrying out the invention]

[0011] Embodiments of the transport vehicle and transport equipment will be described with reference to the drawings. As shown in Figure 1, the transport equipment 100 of this embodiment includes a transport vehicle 1 that travels along a predetermined travel path 9. The transport equipment 100 includes a plurality of transport vehicles 1 that travel along a common travel path 9. Such transport equipment 100 is installed and used in a factory that transports and assembles objects C placed on the transport vehicles 1. As an example, the transport equipment 100 can be used in an automobile manufacturing plant where an automobile is assembled by sequentially attaching various parts to a transport vehicle 1 carrying an automobile body as the object C, while moving the transport vehicle 1 along the travel path 9.

[0012] The travel path 9 in this embodiment includes a straight section 91 and an arc-shaped section 92. The straight section 91 includes a first straight section 91A, a second straight section 91B, and a third straight section 91C. In this embodiment, the first straight section 91A and the second straight section 91B are arranged parallel to each other, with one end of each connected by the arc-shaped section 92 and the other end connected by the third straight section 91C. As a result, the travel path 9 is a circular path that connects in the order of first straight section 91A → arc-shaped section 92 → second straight section 91B → third straight section 91C, and has at least a portion of both a straight section 91 and an arc-shaped section 92.

[0013] Here, the travel path 9 is the path along which the transport vehicle 1, carrying the object to be transported C (for example, the body of an automobile), travels. This travel path 9 is defined by guide members 96 (see Figure 2) installed on the travel surface 95 on which the transport vehicle 1 travels. Such guide members 96 may be physical means such as rails, or they may be software means such as magnetic markers, light-reflective tape, electromagnetic induction cables, or two-dimensional markers. In other words, the travel path 9 may be a physical path predetermined by physical means, or it may be a virtual path determined each time by software means.

[0014] The transport vehicle 1 is guided by the guide member 96 and travels in a circular motion along the travel path 9. In this embodiment, the transport vehicle 1 is configured as an unmanned transport vehicle capable of automatic operation without a driver. In this embodiment, as shown in Figure 1, the transport vehicle 1 travels along the circular travel path 9 while maintaining the orientation of the vehicle body 2. Note that "maintaining the orientation of the vehicle body 2" means maintaining the overall orientation of the vehicle body 2, and is a concept that allows for very slight changes in the posture of the vehicle body 2 that occur during the actual movement of the transport vehicle 1.

[0015] As shown in Figures 2 and 3, the transport vehicle 1 comprises a vehicle body 2, a drive unit 3, and a coupling device 4. The transport vehicle 1 also further comprises a power supply device 51, a control device 52, and a power cable 55.

[0016] The vehicle body 2 includes a vehicle body main body 21 and a storage part 22. The vehicle body main body 21 is the main body part of the vehicle body 2 and is the part that serves as the base of the entire carrier vehicle 1. The vehicle body main body 21 is formed in a rectangular shape in plan view (more specifically, a rectangular shape with rounded corners at the four corners). Also, the vehicle body main body 21 is formed in a vertically long rectangular shape with a longer length in the front-back direction L than in the width direction W.

[0017] The upper surface of the vehicle body main body 21 serves as a placement surface 21a for placing the object C to be conveyed. A part of the placement surface 21a (for example, the peripheral part) may be a space (access space) for an operator to enter for performing a predetermined operation on the object C to be conveyed.

[0018] The storage part 22 is provided so as to protrude downward from the vehicle body main body 21 at the central part in the front-back direction L of the vehicle body main body 21. Inside the storage part 22, a power supply device 51 and a control device 52 are stored. The power supply device 51 and the control device 52 are provided at a position near the central part of the vehicle body 2 and closer to the running surface 95 than the vehicle body main body 21.

[0019] The drive unit 3 includes wheels 31, a running drive source 32, a support member 33, and a steering device 34. In the present embodiment, the drive unit 3 includes a pair of wheels 31, a pair of running drive sources 32 corresponding to the pair of wheels 31, a support member 33, and a steering device 34. Also, two sets of such drive units 3 are provided, and the two sets of drive units 3 are arranged separately in the front-back direction L of the vehicle body 2.

[0020] The wheels 31 rotate around the rotation axis Xr. The wheels 31 in the present embodiment are all drive wheels connected to the running drive source 32. The wheels 31 are driven by the running drive source 32 to apply a propulsive force in the traveling direction T (see FIG. 4), which is a direction orthogonal to the rotation axis Xr.

[0021] The drive source 32 is connected to the wheel 31 so as to be able to transmit driving force. The drive source 32 may be connected so as to rotate integrally with the wheel 31, or it may be connected to the wheel 31 via a transmission (e.g., a reduction gear). In either case, the drive source 32 rotates the wheel 31 with its driving force. In this embodiment, one drive source 32 is connected to one wheel 31 so as to be able to transmit driving force. An electric motor is an example of a drive source 32.

[0022] The support member 33 supports the wheels 31 and the drive source 32, which are connected to each other in a manner that allows them to transmit driving force, to the vehicle body 2. In this embodiment, the support member 33 commonly supports a pair of wheels 31 that are arranged coaxially with each other. The support member 33 is positioned between the pair of wheels 31 along the steering axis Xs which runs in the vertical direction.

[0023] The steering device 34 rotates the wheels 31 around the steering axis Xs which is aligned vertically. In this embodiment, the steering device 34 rotates a pair of wheels 31, which are arranged coaxially with each other, collectively around the steering axis Xs. As shown in Figure 4, the steering device 34 is configured to rotate in the direction of travel T, which is perpendicular to the rotation axis Xr of the wheels 31 when viewed vertically, within a range of ±θ° around the steering axis Xs with respect to a predetermined reference direction R. Here, θ is a preset value less than 360. Figure 4 shows an example where θ is set to a value slightly greater than 90.

[0024] Furthermore, in the example shown in Figure 4, the longitudinal direction L of the vehicle body 2 is defined as the reference direction R, in accordance with general specifications. If the angle between the reference direction R and the longitudinal direction L of the vehicle body 2 is γ°, then in this example, γ=0. In this configuration, the steering device 34 rotates the wheels 31 around the steering axis Xs, thereby changing the steering angle of the drive unit 3 within a range of θ° on both the left and right sides.

[0025] The steering device 34 is not limited in its specific means, as long as it can rotate the wheels 31 around the steering axis Xs. The steering device 34 may consist of tangible means (e.g., a drive transmission mechanism) including a drive source for steering (e.g., a steering motor) and a transmission mechanism (e.g., a gear mechanism or a link mechanism), or it may consist of intangible means including control over a pair of wheels 31.

[0026] In this embodiment, the latter configuration is adopted, and more specifically, the pair of wheels 31 are configured to rotate around the steering axis Xs by making their rotational speeds different. In this case, the steering device 34 is configured by the rotational speed control of the wheels 31 performed in cooperation with the control device 52 and the driving source 32.

[0027] As shown in Figures 2 and 3, the drive unit 3 is connected to the vehicle body 2 via a coupling device 4, which will be described later. In this embodiment, two coupling devices 4 are provided, and the two coupling devices 4 are arranged separately in the longitudinal direction L of the vehicle body 2. In this embodiment, the coupling device 4 provided on the front side in the longitudinal direction L is called the "front coupling device 4F," and the coupling device 4 provided on the rear side in the longitudinal direction L is called the "rear coupling device 4R." The front coupling device 4F and the rear coupling device 4R are arranged on opposite sides of each other in the longitudinal direction L, with the power supply unit 51 and the control device 52 in between.

[0028] As described above, in this embodiment, two sets of drive units 3 are arranged separately in the longitudinal direction L of the vehicle body 2. In this embodiment, the drive unit 3 provided on the front side in the longitudinal direction L is called the "front wheel unit 3F," and the drive unit 3 provided on the rear side in the longitudinal direction L is called the "rear wheel unit 3R." The front wheel unit 3F and the rear wheel unit 3R are arranged on opposite sides of each other in the longitudinal direction L, with the power supply unit 51 and the control device 52 in between.

[0029] The front wheel unit 3F comprises a right front wheel 31FR and a left front wheel 31FL, which are arranged coaxially with each other as wheels 31. The front wheel unit 3F also comprises a drive source 32, which is a right front wheel drive source 32FR connected to the right front wheel 31FR and a left front wheel drive source 32FL connected to the left front wheel 31FL. The front wheel unit 3F also comprises a support member 33F, which is a front wheel support member 33F that commonly supports the right front wheel 31FR and the left front wheel 31FL. The front wheel unit 3F also comprises a steering device 34F, which is a front wheel steering device 34F that rotates the right front wheel 31FR and the left front wheel 31FL around the steering axis Xs. The front wheel unit 3F is connected to the vehicle body 2 by a front coupling device 4F.

[0030] The rear wheel unit 3R comprises a right rear wheel 31RR and a left rear wheel 31RL, which are arranged coaxially as wheels 31. The rear wheel unit 3R also comprises a drive source 32, which is connected to the right rear wheel 31RR and a right rear wheel drive source 32RR, and which is connected to the left rear wheel 31RL. The rear wheel unit 3R also comprises a support member 33R, which commonly supports the right rear wheel 31RR and the left rear wheel 31RL. The rear wheel unit 3R also comprises a steering device 34R, which rotates the right rear wheel 31RR and the left rear wheel 31RL around the steering axis Xs. The rear wheel unit 3R is connected to the vehicle body 2 by a rear coupling device 4R.

[0031] The power supply unit 51 supplies power to drive the transport vehicle 1. The power supply unit 51 supplies power to at least the drive source 32 and the control device 52. In addition, the power supply unit 51 may also supply power to other components, such as various sensors provided on various parts of the vehicle body 2. As the power supply unit 51, for example, a secondary battery such as a lithium-ion battery, an electrolytic capacitor, an electric double-layer capacitor, etc. can be used.

[0032] The control device 52 primarily controls the drive source 32. The control device 52 includes, for example, a driver unit having a driver circuit including semiconductor elements, and a control board for controlling the operation of the semiconductor elements included in the driver unit. The control device 52 receives commands from a higher-level controller (a higher-level control device that controls the entire transport equipment 100), which is not shown in the figure, and executes drive control of the drive source 32 to make the transport vehicle 1 travel along the travel path 9.

[0033] The power supply unit 51 and the control device 52 are mounted in the center of the vehicle body 2 in the longitudinal direction L. The power supply unit 51 and the control device 52 are housed in a housing 22 provided in the center of the vehicle body 2 in the longitudinal direction L. Figures 2 and 3 show a configuration in which the power supply unit 51 and the control device 52 are stacked vertically, but they may also be arranged side by side in the longitudinal direction L.

[0034] As shown in Figure 5, the power cable 55 electrically connects the power supply unit 51 and the drive unit 3. Note that Figure 5 is a plan view focusing on the arrangement below the vehicle body 21, and only the outer shape of the vehicle body 21 is shown, with the coupling device 4 omitted. The power cable 55 electrically connects the power supply unit 51, which is fixed to the vehicle body 2, and the drive unit 3, which is supported on the vehicle body 2 so as to be rotatable around the steering axis Xs. The power cable 55 has a fixed connection part 55f at one end and a movable connection part 55m at the other end. The power cable 55 is connected to the power supply unit 51 by the fixed connection part 55f and to the drive unit 3 by the movable connection part 55m.

[0035] Here, the fixed connection part 55f is connected to the power supply unit 51 and its position relative to the vehicle body 2 is constant, while the movable connection part 55m is connected to the drive unit 3 and rotates together with the steerable wheels 31. The position of the movable connection part 55m in plan view may change depending on the rotation state of the drive unit 3. Furthermore, the shape of the power cable 55 in plan view may also change depending on the position of the movable connection part 55m. For this reason, the power cable 55 is housed in a protective cover 56 that is connected in a chain-like manner and whose external shape can be deformed.

[0036] It is also conceivable that the electrical connection between the power supply unit 51 and the drive unit 3 could be made using a rotary connector or slip ring. Using a rotary connector or slip ring is preferable because it allows the drive unit 3 to rotate freely 360°. However, when using these means, the power required to drive the drive unit 3 is limited to a relatively small power limit. For this reason, in a transport vehicle 1 that transports heavy objects such as the body of an automobile as the transported object C, as in this embodiment, it is necessary to use a power cable 55 that can handle high power rather than a rotary connector or slip ring.

[0037] While the use of power cables 55 allows for handling high power, as mentioned above, the maximum steering angle when the steering device 34 rotates the wheels 31 around the steering axis Xs is limited to θ° on both the left and right sides (see Figure 4). Due to this constraint, when the transport vehicle 1 travels along the circular route 9 shown in Figure 1, it was necessary to stop the transport vehicle 1 once the drive unit 3 had turned to its maximum steering angle to the left and reset the direction of the drive unit 3.

[0038] In this regard, the transport vehicle 1 of this embodiment reduces the number of times it is necessary to stop along the way and reset the orientation of the drive unit 3 by partially modifying the coupling device 4 that is provided to connect the vehicle body 2 and the drive unit 3.

[0039] As shown in Figures 2 and 3, the coupling device 4 is equipped with a mounting portion 41 that is attached to the vehicle body 2. The mounting portion 41 is made up of, for example, a plate-shaped member and is fixed to the lower surface of the vehicle body 21. In plan view, the mounting portion 41 is formed in the shape of a deformed home plate with a cut-off tip, or a deformed trapezoidal shape that combines a trapezoid and a rectangle. The drive unit 3 is attached to the mounting portion 41 via a support member 33.

[0040] As described above, in this embodiment, the coupling device 4 includes a front coupling device 4F and a rear coupling device 4R. The front coupling device 4F is equipped with a front mounting portion 41F, and the rear coupling device 4R is equipped with a rear mounting portion 41R. The front wheel unit 3F is attached to the front mounting portion 41F via a front wheel support member 33F, and the rear wheel unit 3R is attached to the rear mounting portion 41R via a rear wheel support member 33R.

[0041] The coupling device 4 is further equipped with an adjustment mechanism 42 that allows the reference direction R to be changed around the steering axis Xs with respect to the longitudinal direction L of the vehicle body 2 by changing the mounting position of the mounting portion 41 to the vehicle body 2. As can be clearly seen from the comparison between Figure 4 and Figure 6, the coupling device 4 is equipped with the adjustment mechanism 42, so that the orientation of the modified home plate-shaped or modified trapezoidal mounting portion 41 can be changed while the position of the steering axis Xs with respect to the vehicle body 2 remains unchanged. Accordingly, the reference direction R of the drive unit 3 with respect to the longitudinal direction L of the vehicle body 2 can be changed.

[0042] The adjustment mechanism 42 can change the reference direction R within a range of γ° with respect to the longitudinal direction L of the vehicle body 2. Here, the magnitude of γ is not particularly limited (i.e., it is sufficient if it can be changed even a little), but when θ is set to a value greater than 90 (and less than 180), as in this embodiment, it is preferable that γ be set to a value of 90 or greater. Furthermore, it is preferable that γ be set to a multiple of 90 (i.e., 90, 180, or 270). In the example in Figure 6, the adjustment mechanism 42 changes the reference direction R 90° to the left with respect to the longitudinal direction L of the vehicle body 2. As a result, the angle γ° between the reference direction R and the longitudinal direction L of the vehicle body 2 is 90°.

[0043] Referring to the example in Figure 6, the drive unit 3 is capable of rotating within a range of ±θ° around the steering axis Xs with respect to a reference direction R which is 90° to the left with respect to the longitudinal direction L of the vehicle body 2. In this example, as mentioned above, θ is set to a value slightly greater than 90. Therefore, for example, in the transport equipment 100 in Figure 1, the transport vehicle 1 can be driven along the first straight section 91A with the direction of travel T by the drive unit 3 changed by 90° to the right with respect to the reference direction R.

[0044] When the transport vehicle 1 enters the arc-shaped section 92, the steering angle of the drive unit 3 can be gradually changed according to the position of the transport vehicle 1 so that the direction of travel T points tangentially to the arc-shaped section 92. As can be seen from Figure 6, the direction of travel T can be continuously changed from a state where it is 90° to the right relative to the reference direction R to a state where it is 90° to the left relative to the reference direction R, without stopping along the way. Therefore, the transport vehicle 1 can be driven continuously from the first straight section 91A through the arc-shaped section 92 to the second straight section 91B.

[0045] Furthermore, when transitioning from the second straight section 91B to the third straight section 91C, and when transitioning again from the third straight section 91C to the first straight section 91A, the orientation of the drive unit 3 needs to be reset. Nevertheless, when considering the entire circular route 9, a long distance is secured over which the transport vehicle 1 can travel continuously (in other words, the number of times it has to stop is reduced), and the transport efficiency of the transport vehicle 1 is improved.

[0046] As shown in Figure 7, the adjustment mechanism 42 of this embodiment includes a through hole 42B formed to penetrate the mounting portion 41 in the thickness direction, and a fixing bolt 42A that is inserted through the through hole 42B and fastened to the vehicle body 21. The vehicle body 21 has a screw hole into which the fixing bolt 42A is fastened, and this screw hole also constitutes part of the adjustment mechanism 42. Thus, part of the adjustment mechanism 42 may be provided in the vehicle body 21.

[0047] In this embodiment, four through holes 42B are formed at the vertices of a square centered on the steering axis Xs. This makes it possible to easily change the reference direction R in 90° increments.

[0048] [Other Embodiments] (1) In the above embodiment, an example was described in which the adjustment mechanism 42 is configured to change the reference direction R in 90° increments with respect to the longitudinal direction L of the vehicle body 2. However, the configuration is not limited to such an example, and the adjustment mechanism 42 may be configured to change the reference direction R in predetermined angular units such as 45°, 22.5°, or 60° with respect to the longitudinal direction L of the vehicle body 2. Alternatively, the adjustment mechanism 42 may be configured to change the angle of the reference direction R linearly with respect to the longitudinal direction L of the vehicle body 2.

[0049] (2) In the above embodiment, the adjustment mechanism 42 was described assuming a configuration in which the reference direction R can be changed with respect to the longitudinal direction L of the vehicle body 2 only when the transport vehicle 1 is stopped. However, the configuration is not limited to such a configuration, and for example, the adjustment mechanism 42 may be able to automatically change the reference direction R with respect to the longitudinal direction L of the vehicle body 2 while the transport vehicle 1 is in motion. Such a configuration may include, for example, a drive source for adjustment (e.g., an adjustment motor) and a transmission mechanism (e.g., a gear mechanism or a linkage mechanism).

[0050] (3) In the above embodiment, the transport vehicle 1 may further be provided with notification means for notifying the control device 52 when the reference direction R is changed. A physical mechanism such as a toggle switch or a knob can be used as the notification means. In this case, the operator may operate the notification means at the same time as changing the orientation of the adjustment mechanism 42. Alternatively, the notification means may be a transmitter of a signal indicating that the reference direction R has been changed. The signal indicating the change of the reference direction R may be notified directly from an interface provided on the transport vehicle 1, or it may be notified indirectly via a higher-level controller or the like.

[0051] (4) In the above embodiment, the transport vehicle 1 may further be equipped with a rotation angle sensor for detecting the orientation of each drive unit 3. This rotation angle sensor may be configured to always use the front-rear direction L of the vehicle body 2 as the absolute reference. In this case, for example, when starting the transport vehicle 1, the control device 52 can determine the reference direction R of each drive unit 3 based on the detected range of motion by rotating each drive unit 3 to its limit to the left and right.

[0052] (5) In the above embodiment, the transport vehicle 1 may further include control cables (including control signal lines and sensor wiring, etc.) that connect the control device 52 and the drive unit 3. In this case, the control cables may be housed together with the power cables 55 inside the protective cover 56. The transport vehicle 1 may also further include various sensors, such as obstacle sensors that detect the presence of obstacles. In this case, detection cables (including sensor wiring, etc.) that connect the various sensors to the control device 52 may further be included, and these detection cables may be housed together with the power cables 55 inside the protective cover 56.

[0053] (6) In the above embodiment, a configuration in which the power cable 55 is housed within a protective cover 56 was described as an example. However, the configuration is not limited to such an example, and the power cable 55 may be installed without protection.

[0054] (7) In the above embodiment, the steering axis Xs, which is the pivot axis of the wheel 31 by the steering device 34, was described assuming a configuration in which it is aligned with the vertical direction. However, the configuration is not limited to this, and the steering axis Xs may be slightly inclined with respect to the vertical direction (for example, inclined at an angle of inclination of 10° or less with respect to the vertical direction). With respect to the steering axis Xs, such an arrangement in which it is slightly inclined with respect to the vertical direction is also included in the concept of "aligned with the vertical direction".

[0055] (8) In the above embodiment, a configuration in which four wheels 31 are provided per transport vehicle 1 was described as an example. However, the configuration is not limited to this, and the number of wheels 31 per transport vehicle 1 may be, for example, three or five or more. Some of the multiple wheels 31 may not be drive wheels connected to the drive source 32, but rather auxiliary wheels that simply rotate freely.

[0056] (9) In the above embodiment, the configuration described as one in which the arc-shaped section 92 included in the travel path 9 is formed in a shape corresponding to a part of a circle arc (specifically, a semicircle) was described as an example. However, the configuration is not limited to such one, and the arc-shaped section 92 may have a shape that has a straight portion in the middle, for example, or a shape in which the curvature changes depending on the part.

[0057] (10) In the above embodiment, the transport vehicle 1 was described as an unmanned transport vehicle capable of autonomous driving without a driver. However, the transport vehicle 1 is not limited to such a configuration, and may be a manned transport vehicle (for example, a forklift) operated by a person.

[0058] (11) The configurations disclosed in each of the above-described embodiments (including the above-described embodiments and other embodiments; the same applies hereinafter) can be applied in combination with configurations disclosed in other embodiments, insofar as they do not cause a conflict. With respect to other configurations, the embodiments disclosed herein are illustrative in all respects and can be modified as appropriate without departing from the spirit of the disclosure.

[0059] [Summary of the Embodiments] In summary, the transport vehicle according to this disclosure preferably comprises the following components.

[0060] A transport vehicle comprising a vehicle body, a drive unit, and a coupling device for connecting the vehicle body and the drive unit, The drive unit comprises a wheel, a drive source for rotating the wheel, and a steering device for rotating the wheel around a steering axis along the vertical direction. The steering device is configured to be able to rotate in the direction of travel, which is perpendicular to the rotation axis of the wheels when viewed from above, within a range of ±θ° around the steering axis with respect to a predetermined reference direction (where θ is a predetermined value less than 360). The coupling device comprises a mounting portion attached to the vehicle body, and an adjustment mechanism that allows the reference direction to be changed around the steering axis with respect to the longitudinal direction of the vehicle body by changing the mounting position of the mounting portion to the vehicle body.

[0061] With this configuration, when a transport vehicle travels along a circular path that has, for example, at least part of an arc-shaped section without changing the orientation of the vehicle body, the mounting position of the mounting part to the vehicle body can be changed using the adjustment mechanism, and the reference direction can be biased in advance towards the side that will rotate the drive unit while traveling through the arc-shaped section. As a result, even if the maximum steering angle of the drive unit (wheels) by the steering device is limited to less than 360° on both the left and right sides, a wide range of arc-shaped sections can be secured in which the transport vehicle can travel continuously while gradually changing the steering angle of the drive unit. In other words, the number of times the transport vehicle needs to stop in the middle of an arc-shaped section to change the steering angle of the drive unit can be reduced. Therefore, the transport efficiency of the transport vehicle can be increased.

[0062] As one aspect, Preferably, the adjustment mechanism can change the reference direction within a range of γ° (where γ is a preset value greater than or equal to θ) with respect to the longitudinal direction of the vehicle body.

[0063] With this configuration, for example, in the above-mentioned case, the adjustment mechanism can be used to pre-determine the reference direction to the side that will rotate the drive unit while traveling through the arc-shaped section, up to the maximum steering angle. This ensures that the range of the arc-shaped section over which the transport vehicle can continuously travel while gradually changing the direction of the drive unit is wide enough to match the maximum steering angle.

[0064] As one aspect, Preferably, the adjustment mechanism allows the reference direction to be changed in 90° increments within a range of γ° (where γ is a preset value of 90 or more, and θ is a preset value of 90 or more but less than 180) with respect to the longitudinal direction of the vehicle body.

[0065] With this configuration, for example, in the above-mentioned case, by using the adjustment mechanism to pre-determine the reference direction to be 90° towards the side that will rotate the drive unit while traveling through the arc-shaped section, the transport vehicle can travel through the arc-shaped section continuously for half a turn while gradually changing the direction of the drive unit. Furthermore, since the adjustment mechanism changes the reference direction in 90° increments, the configuration of the adjustment mechanism can be simplified.

[0066] As one aspect, The vehicle comprises a power supply unit mounted on the vehicle body and a power cable that electrically connects the power supply unit and the drive unit, Preferably, the power cable includes a fixed connection portion connected to the power supply unit and whose position relative to the vehicle body remains unchanged, and a movable connection portion connected to the drive unit and which rotates together with the steered wheels.

[0067] With this configuration, even when the power required to drive the drive unit is high, the power supply and the drive unit can be properly electrically connected using a power cable. On the other hand, using a power cable limits the maximum steering angle of the drive unit (wheels), but by incorporating the adjustment mechanism described above, a wide range of arc-shaped sections can be secured in which the transport vehicle can continuously travel while gradually changing the direction of the drive unit.

[0068] As one aspect, The aforementioned drive unit includes a front wheel unit and a rear wheel unit. The coupling device includes a front coupling device and a rear coupling device. The front wheel unit comprises a right front wheel and a left front wheel arranged coaxially with each other, and is connected to the vehicle body by the front coupling device. The rear wheel unit preferably comprises a right rear wheel and a left rear wheel arranged coaxially with respect to each other, and is connected to the vehicle body by the rear coupling device.

[0069] With this configuration, the transport vehicle can be driven stably using at least four wheels, including the right front wheel, left front wheel, right rear wheel, and left rear wheel.

[0070] Furthermore, the conveying equipment relating to this disclosure preferably comprises the following configurations.

[0071] A transport system equipped with transport vehicles of the above-described configurations that travel along a predetermined route, The aforementioned route is a circular route having at least a portion of an arc-shaped section, The transport vehicle travels along the circular route while maintaining the orientation of its body.

[0072] As shown in this configuration, the transport vehicles described above can be suitably applied to transport equipment in which the transport vehicle travels around a circular path having at least a portion of an arc-shaped section without changing the orientation of the vehicle body.

[0073] As one aspect, The aforementioned travel path is defined by guide members installed on the travel surface on which the transport vehicle travels. It is preferable that the transport vehicle travels while being guided by the guide member.

[0074] With this configuration, the transport vehicle can travel appropriately along the travel path where the guide members are installed. Furthermore, if feedback control is used to guide the transport vehicle along the guide members, for example, the transport vehicle does not need to recognize the origin position of the steering angle. Therefore, even if the angle in the reference direction is adjusted by the adjustment mechanism, the effort required to change the control settings can be reduced.

[0075] The transport vehicle and transport equipment relating to this disclosure only need to achieve at least one of the effects described above. [Explanation of Symbols]

[0076] 1. Transport vehicle 2 car bodies 3. Drive Unit 3F Front Wheel Unit 3R Rear Wheel Unit 4 Coupling device 4F Front coupling device 4R rear coupling device 9. Route 21 Body 31 wheels 31FR Right Front Wheel 31FL left front wheel 31RR Right rear wheel 31RL left rear wheel 32. Drive source 34 Steering gear 41 Mounting part 42 Adjustment mechanism 51 Power supply 55 Power Cables 55f Fixed connection section 55m movable connection section 91 Straight section 92 Arc-shaped section 95 Running surface 96 Induction Member 100 Conveying equipment Xs steering axis Xr wheel rotation axis T Direction of travel R Reference direction L Anteroposterior direction θ Maximum steering angle γ adjustment angle

Claims

1. A transport vehicle comprising a vehicle body, a drive unit, and a coupling device for connecting the vehicle body and the drive unit, The drive unit comprises a wheel, a drive source for rotating the wheel, and a steering device for rotating the wheel around a steering axis along the vertical direction. The steering device is configured to be able to rotate in the direction of travel, which is perpendicular to the rotation axis of the wheels when viewed from above, within a range of ±θ° around the steering axis with respect to a predetermined reference direction (where θ is a predetermined value less than 360). A transport vehicle comprising a coupling device, a mounting portion attached to the vehicle body, and an adjustment mechanism that changes the reference direction relative to the longitudinal direction of the vehicle body around the steering axis by changing the mounting position of the mounting portion to the vehicle body.

2. The transport vehicle according to claim 1, wherein the adjustment mechanism can change the reference direction within a range of γ° with respect to the longitudinal direction of the vehicle body (where γ is a preset value greater than or equal to θ, excluding multiples of 360).

3. The adjustment mechanism sets the reference direction to γ° with respect to the longitudinal direction of the vehicle body (where γ is a preset value of 90 or more, and θ is a preset value of 90 or more but less than 180). The transport vehicle according to claim 1, which can be changed in 90° increments within the range of ).

4. The vehicle comprises a power supply unit mounted on the vehicle body and a power cable that electrically connects the power supply unit and the drive unit, The transport vehicle according to claim 1, wherein the power cable comprises a fixed connection portion connected to the power supply device and whose position relative to the vehicle body is unchanging, and a movable connection portion connected to the drive unit and which rotates together with the wheel that is steered.

5. The aforementioned drive unit includes a front wheel unit and a rear wheel unit. The coupling device includes a front coupling device and a rear coupling device. The front wheel unit comprises a right front wheel and a left front wheel arranged coaxially with each other, and is connected to the vehicle body by the front coupling device. The transport vehicle according to claim 1, wherein the rear wheel unit comprises a right rear wheel and a left rear wheel arranged coaxially with respect to each other as wheels, and is connected to the vehicle body by the rear coupling device.

6. A transport system comprising a transport vehicle according to any one of claims 1 to 5, which travels along a predetermined route, The aforementioned route is a circular route having at least a portion of an arc-shaped section, The transport vehicle is a transport device that travels along the circular route while maintaining the orientation of the vehicle body.

7. The aforementioned travel path is defined by guide members installed on the travel surface on which the transport vehicle travels. The transport vehicle travels guided by the guide member, as described in claim 6.

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