Transport vehicle

Abstract

This enables the creation of a transport vehicle that can easily minimize the area required for turning. [Solution] A transport vehicle 100 comprises a fork 15 that supports a pallet P, a lifting device, a travel drive device 13, a first wheel 11, and a vehicle body 30 that supports a pair of second wheels 12, wherein the vehicle body 30 is formed such that, in a vertical view, it fits within a region E1 within the reference radius R1 from the vehicle body pivot axis C2, based on the radius R1 determined by the distance between the furthest end of the pallet P supported at a reference position set on the fork 15 and the vehicle body pivot axis C2.

Description

Technical Field

[0001] The present invention relates to a carrier provided with forks.

Background Art

[0002] Japanese Patent Application Laid-Open No. 2005-289525 (Patent Document 1) discloses a carrier provided with forks. This carrier has front wheels (4L, 4R) and rear wheels (5, 6) and is configured to be rotatable about turning center points (P1, P2).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] A carrier as described above can be considered to run in facilities such as warehouses and factories. However, in such facilities, the area of the passage is limited, and when the area required for the carrier to turn is large, problems may occur such that the carrier cannot turn at the desired location or a wide passage must be secured for the carrier to turn.

[0005] Therefore, it is desired to realize a carrier that can easily suppress the area required for the carrier to turn.

Means for Solving the Problems

[0006] The transport vehicle according to this disclosure comprises a fork for supporting a pallet, a lifting device for raising and lowering the fork, a first wheel that rotates around a first rotation axis, a pair of second wheels that rotate around a second rotation axis, a drive device for driving at least one of the first wheel and the pair of second wheels, and a vehicle body that supports the lifting device, the drive device, the first wheel, and the pair of second wheels, wherein a specific direction along a horizontal plane is defined as the front-rear direction, a direction along the horizontal plane that is perpendicular to the front-rear direction is defined as the width direction, one side in the front-rear direction is defined as the front side, the other side in the front-rear direction is defined as the rear side, one side in the width direction is defined as the first width direction side, and the other side in the width direction is defined as the second width direction side, and the fork protrudes from the lifting device toward the rear side. The vehicle body is arranged in such a manner that it comprises a main body and a pair of legs arranged to protrude from the main body toward the rear on the first and second sides in the width direction relative to the lifting trajectory of the forks, with the pair of legs supporting each of the pair of second wheels, the second rotation axis is a rotation axis along the width direction, and the axis passing through the midpoint of the pair of second wheels on the second rotation axis and along the vertical direction is the vehicle body pivot axis, and the radius determined based on the distance between the furthest end of the pallet supported at a reference position set on the forks and the vehicle body pivot axis is used as the reference radius, and the vehicle body is formed so that, in a vertical view, it fits within the area from the vehicle body pivot axis to the reference radius.

[0007] With this configuration, the vehicle body is formed so that, when viewed from above, it fits within a region within the reference radius from the vehicle's pivot axis. Therefore, the area required for the transport vehicle to turn can be easily kept small. Consequently, it is easy to travel in narrow areas. [Brief explanation of the drawing]

[0008] [Figure 1] A perspective view of the transport vehicle of this embodiment, viewed from the front. [Figure 2] Perspective view of the transport vehicle in Figure 1, seen from the rear. [Figure 3] Figure 1 is a bottom view showing the transport vehicle in a straight-line position. [Figure 4] Figure 1 is a bottom view showing the transport vehicle in a turning position. [Figure 5] Front view of the transport vehicle in Figure 1, showing the counterweight at its upper limit position. [Figure 6] Front view of the transport vehicle in Figure 1, showing the counterweight at its lower limit position. [Figure 7] Figure 1 shows a side view of the counterweight of the transport vehicle. [Figure 8] Figure 1 shows the upper surface of the counterweight of the transport vehicle. [Figure 9] Figure 1 shows the upper surface of the swivel support section of the transport vehicle. [Modes for carrying out the invention]

[0009] The embodiments of the transport vehicle 100 will be described below with reference to the drawings. Figure 1 is a perspective view showing an example of the front of the transport vehicle 100. Figure 2 is a perspective view showing an example of the rear of the transport vehicle 100. The transport vehicle 100 is used in facilities such as warehouses, factories, and ships. In this embodiment, the transport vehicle 100 is an unmanned transport vehicle that does not carry a person.

[0010] Figure 3 shows an example of the underside of the transport vehicle 100. The transport vehicle 100 is equipped with a plurality of wheels, including drive wheels. The plurality of wheels have first wheels 11 that rotate around a first rotation axis A1. The plurality of wheels have a pair of second wheels 12 that rotate around a second rotation axis A2. The transport vehicle 100 is equipped with a travel drive device 13 that drives the drive wheels.

[0011] Here, the specific direction along the horizontal plane is defined as the longitudinal direction X. One side of the longitudinal direction X is defined as the front side X1, and the other side of the longitudinal direction X is defined as the rear side X2. The direction along the horizontal plane that is perpendicular to the longitudinal direction X is defined as the width direction Y. One side of the width direction Y is defined as the first width direction Y1, and the other side of the width direction Y is defined as the second width direction Y2. The second rotation axis A2 is the rotation axis along the width direction Y. The vertical direction Z refers to the vertical direction when the transport vehicle 100 is positioned on a horizontal plane.

[0012] The drive unit 13 drives at least one of the first wheel 11 and the pair of second wheels 12. In this embodiment, the first wheel 11 is the drive wheel. In this embodiment, the pair of second wheels 12 are the driven wheels.

[0013] The running gear 13 includes a wheel drive source 14. In this embodiment, the multiple wheels have a pair of first wheels 11. The running gear 13 includes a pair of wheel drive sources 14 so that each of the pair of first wheels 11 can be driven independently.

[0014] The transport vehicle 100 is equipped with forks 15 that support the pallet P. In this embodiment, the forks 15 are branched into two. The forks 15 may also be branched into three or more. Alternatively, the forks 15 may be a single flat plate-shaped member. As the pallet P, various existing pallets commonly used in the logistics industry can be used. In this embodiment, there are multiple types of pallets P with different dimensions, but there may be only one type.

[0015] As shown in Figure 2, the transport vehicle 100 is equipped with a lifting device 20 for raising and lowering the forks 15. The forks 15 are positioned to protrude from the lifting device 20 toward the rear X2. The lifting device 20 is equipped with a guide mechanism 22.

[0016] The guide mechanism 22 includes guide rails 18 arranged along the vertical direction Z. The guide rails 18 are formed to extend along the vertical direction Z. In this embodiment, the guide mechanism 22 includes a pair of guide rails 18, each arranged along the vertical direction Z and spaced apart from each other in the width direction Y.

[0017] The guiding mechanism 22 includes a first guided member 22a that is connected to the fork 15 and guided along the vertical direction Z by the guide rails 18. In the present embodiment, the first guided member 22a is a roller. In the present embodiment, the guiding mechanism 22 includes a pair of first guided members 22a that are connected to the fork 15 and guided along the vertical direction Z by each of the pair of guide rails 18. The pair of first guided members 22a are arranged so as to contact each of the pair of guide rails 18 from the inside in the width direction Y with respect to the pair of guide rails 18.

[0018] Each of the pair of first guided members 22a is configured to roll along the guide rail 18. In the present embodiment, each of the pair of first guided members 22a is configured to be rotatable about a rotation axis along the width direction Y. Each of the pair of first guided members 22a is arranged to roll on a pair of rolling surfaces of the guide rail 18 that face each other in the front-rear direction X.

[0019] As shown in FIG. 2, the lifting device 20 includes a lifting drive device 24 provided with a lifting drive source 25. The lifting device 20 raises and lowers the fork 15 by the driving force of the lifting drive source 25. The lifting device 20 includes guide rails 18 arranged along the vertical direction Z. The lifting drive device 24 includes a speed reducer 26. The driving force of the lifting drive source 25 is transmitted to a connecting member 27 described later via the speed reducer 26. In the present embodiment, the speed reducer 26 includes a worm gear.

[0020] The lifting device 20 includes a connecting member 27 that connects the fork 15 and the lifting drive device 24. The connecting member 27 is configured to transmit the driving force of the lifting drive source 25 to the fork 15. In the present embodiment, the connecting member 27 converts the rotational force of the rotor included in the lifting drive source 25 into a force for raising and lowering the fork 15. Examples of the connecting member 27 include a chain, a belt, a rack and pinion, and the like.

[0021] The fork 15 is positioned inward in the width direction Y relative to the pair of guide rails 18 and includes a rail-to-rail arrangement portion 15c that supports a pair of first guided members 22a. In this embodiment, the rail-to-rail arrangement portion 15c rotatably supports the pair of first guided members 22a. In this embodiment, the connecting member 27 is connected to the rail-to-rail arrangement portion 15c.

[0022] In this embodiment, the lifting drive device 24 is a device that raises and lowers the fork 15 via a pair of connecting members 27. In this embodiment, the lifting drive device 24 comprises a pair of sprockets 28 (see Figure 5) around which the pair of connecting members 27 are wound, and a lifting drive source 25 that rotates the pair of sprockets 28.

[0023] At least one of the lifting drive source 25 and the reduction gear 26 is positioned above Z1 the lifting trajectory of the first guided member 22a. At least one of the lifting drive source 25 and the reduction gear 26 is positioned in a location that overlaps with the rail-to-rail arrangement section 15c when viewed in the vertical direction. In this embodiment, the lifting drive device 24 is positioned above Z1 the lifting trajectory of the first guided member 22a and in a location that overlaps with the rail-to-rail arrangement section 15c when viewed in the vertical direction.

[0024] As shown in Figures 1 and 2, the transport vehicle 100 includes a body 30. The body 30 supports a lifting device 20, a travel drive device 13, and a plurality of wheels. In this embodiment, the body 30 supports a first wheel 11 and a pair of second wheels 12. The body 30 is formed in a U-shape when viewed from above. In this embodiment, the position of the fork 15 in the longitudinal direction X relative to the body 30 is fixed.

[0025] The vehicle body 30 includes a cover 30b that covers at least the upper Z1 of the drive unit 13. In this embodiment, the cover 30b is configured to cover at least the upper Z1 of the drive unit 13, the lifting device 20, and the control unit 60, which will be described later.

[0026] The vehicle body 30 includes a main body 31. The main body 31 supports the lifting device 20. In this embodiment, the main body 31 supports the first wheel 11 and the drive unit 13. The vehicle body 30 includes a bumper 35 attached to at least the front X1 of the main body 31. In this embodiment, the bumper 35 is equipped with a contact detection sensor that detects contact with the surface of the bumper 35.

[0027] The vehicle body 30 is equipped with a pair of legs 32 positioned on the first side Y1 and the second side Y2 in the width direction with respect to the lifting trajectory of the fork 15. Here, the lifting trajectory of a member is the path taken when that member moves up and down between a preset upper limit position and a preset lower limit position. The upper limit position and the lower limit position may be set by controllable constraints or by physical constraints.

[0028] The pair of legs 32 are arranged to protrude from the main body 31 toward the rear X2. In this embodiment, the distance K7 between the pair of legs 32 in the width direction Y is greater than the width direction Y dimension of the largest pallet P (see Figure 4).

[0029] A pair of legs 32 support each of a pair of second wheels 12. Each pair of second wheels 12 is positioned inward from the outermost ends 32a of the pair of legs 32, which are the outermost ends in the width direction Y. In this embodiment, each of the pair of legs 32 supports a plurality of second wheels 12 (two in the illustrated example). In this embodiment, bumpers 35 are attached to both outer ends 32a in the width direction Y.

[0030] The main body 31 is equipped with a swivel support section 33. The swivel support section 33 supports the first wheel 11 so that it can rotatably move around a first swivel axis C1 along the vertical direction Z. In this embodiment, the swivel support section 33 supports a pair of first wheels 11 so that they can rotatably move around a first swivel axis C1 along the vertical direction Z.

[0031] Here, the angle around the first pivot axis C1 is defined as the "swing angle". The swing angle is defined as 0 degrees when the first rotation axis A1 and the width direction Y are parallel in a vertical view. In this embodiment, the travel drive unit 13 drives the pair of first wheels 11 so that they rotate at the same speed and in opposite directions, thereby causing the pair of first wheels 11 to swing around the first pivot axis C1.

[0032] Figure 3 shows an example of the first wheel 11 in the first state. The state of the first wheel 11 when the transport vehicle 100 is moving linearly forward or backward is defined as the first state. In the first state, the swivel support 33 supports the first wheel 11 so that the first rotation axis A1 is parallel to the width direction Y when viewed in the vertical direction. When moving linearly forward or backward, the travel drive unit 13 drives the pair of first wheels 11 or the pair of second wheels 12 so that their rotational speeds are the same.

[0033] Figure 4 shows an example of the first wheel 11 in the second state. The state of the first wheel 11 when the transport vehicle 100 rotates around the vehicle body rotation axis C2 which is along the vertical direction Z is defined as the second state. In the second state, the rotation support part 33 supports the first wheel 11 so that the first rotation axis A1 is not parallel to the width direction Y when viewed in the vertical direction. In this embodiment, in the second state, the rotation support part 33 supports the first wheel 11 so that the rotation angle is within the "first set angle range" which includes 90 degrees. Examples of the first set angle range include 90±20 degrees, 90±10 degrees, 90±5 degrees, 90±1 degrees, etc. In this embodiment, when rotating around the vehicle body rotation axis C2, the travel drive device 13 makes the rotation speed of one of the pair of first wheels 11, which is the first wheel 11 closer to the vehicle body rotation axis C2, slower than the rotation speed of the other first wheel 11.

[0034] The state of the first wheel 11 when the transport vehicle 100 moves forward or backward in a curved manner is defined as the third state. In the third state, the swivel support 33 supports the first wheel 11 such that the first rotation axis A1 is not parallel to the longitudinal direction X and the width direction Y when viewed from above. In this embodiment, in the third state, the swivel support 33 supports the first wheel 11 such that the swivel angle is within a "second set angle range" that does not include 0 degrees and 90 degrees. Examples of the second set angle range include 45±35 degrees, 45±25 degrees, 60±10 degrees, etc. In addition, the swivel support 33 in the third state may support the first wheel 11 such that the first rotation axis A1 is parallel to the longitudinal direction X when viewed from above. When moving forward or backward in a curved manner, the travel drive device 13 drives a pair of first wheels 11 or a pair of second wheels 12 so that their rotation speeds are different from each other.

[0035] The swivel support section 33 is configured to support the travel drive unit 13 so that it can rotatably support it around a first swivel axis C1 along the vertical direction Z. In this embodiment, the swivel support section 33 comprises a swivel section 33a and a fixed section 33b. The swivel section 33a is supported by the fixed section 33b so that it can rotatably support the fixed section 33b around the first swivel axis C1.

[0036] The main body 31 includes rail support sections 34 that support the guide rails 18. In this embodiment, the rail support sections 34 are configured to support a pair of guide rails 18. In this embodiment, the rail support sections 34 are fixed to the fixing section 33b. In this embodiment, a pair of rail support sections 34 are provided and are arranged separately on both sides in the width direction Y relative to the swivel support section 33.

[0037] In this embodiment, a rotation position sensor 37 is provided on the vehicle body 30. The rotation position sensor 37 is a sensor that detects whether or not the rotation angle is within a first set angle range. The rotation position sensor 37 is supported by parts of the vehicle body 30 that do not rotate, such as the fixed part 33b and the rail support part 34.

[0038] In this embodiment, a pair of detection units 38 are provided on the swivel unit 33a. The pair of detection units 38 swivel in conjunction with the swivel of the first wheel 11. In this embodiment, when the swivel position sensor 37 detects either of the pair of detection units 38, it is determined that the swivel angle of the travel drive unit 13 is within the above-mentioned first set angle range.

[0039] In this embodiment, the pair of legs 32 support each of the pair of target wheels. In this embodiment, the vehicle rotation axis C2 is an axis that passes through the midpoint of the pair of target wheels on the target rotation axis and is aligned with the vertical direction Z. In this embodiment, the "target rotation axis" is the second rotation axis A2, and the "target wheel" is the second wheel 12. In this embodiment, the midpoint of the pair of target wheels on the target rotation axis is the central position between the pair of second wheels 12 on the second rotation axis A2, i.e., a position equally spaced from each second wheel 12. In this embodiment, the vehicle rotation axis C2 and the rotation trajectory T1 of the first wheel 11 overlap in a longitudinal view along the longitudinal direction X.

[0040] As shown in Figure 4, the vehicle body 30 is formed so that, when viewed in the vertical direction, it falls within a region E1 within a reference radius R1 from the vehicle body pivot axis C2. Here, the foremost surface X1 of the vehicle body 30 is referred to as the frontmost surface 30a. The frontmost surface 30a is formed in a shape that follows a circle centered on the vehicle body pivot axis C2 when viewed in the vertical direction. In this embodiment, a bumper 35 is attached to the frontmost surface 30a.

[0041] In this embodiment, the reference radius R1 is a radius determined based on the distance K1 between the end of the pallet P, which is supported at a reference position set on the fork 15, and the vehicle body pivot axis C2, and the end of the pallet P that is furthest from the vehicle body pivot axis C2. In this embodiment, the reference radius R1 is set based on the largest pallet P, which is the pallet with the largest dimensions.

[0042] Examples of reference positions set on the fork 15 include the position set for the lifting device 20 to move the fork 15 up and down while it is supporting the pallet P, the position set for the transport vehicle 100 to travel while the fork 15 is supporting the pallet P, and the position where the pallet P contacts the base end surface 15b of the fork 15. Whether or not the pallet P is supported at the reference position set on the fork 15 is determined, for example, by whether or not the pallet detection sensor 75, which will be described later, detects the pallet P.

[0043] Examples of reference radius R1 include 1.1 times the distance K1, 1.05 times the distance K1, 1.0 times the distance K1, etc. The closer the reference radius R1 is to the distance K1, the smaller the radius required for the transport vehicle 100 to turn. In this embodiment, the reference radius R1 is greater than or equal to the distance K1.

[0044] The reference radius R1 may be a radius determined based on the distance K2 between the end T1a, which is the foremost X1 end in the turning trajectory T1 of the first wheel 11, and the vehicle body pivot axis C2. Examples of the reference radius R1 in this case include 1.2 times the distance K2, 1.1 times the distance K2, 1.05 times the distance K2, 1.0 times the distance K2, etc. In this embodiment, the reference radius R1 is a value greater than the distance K2. Note that the turning trajectory of the turning section 33a may be used instead of the turning trajectory T1 of the first wheel 11. That is, the distance K2 may be the distance between the foremost X1 end in the turning trajectory of the turning section 33a and the vehicle body pivot axis C2.

[0045] Here, the distance K6 is defined as the distance from the vehicle's pivot axis C2 to the tip 15a of the fork 15 supporting the pallet P. The reference radius R1 is set to be greater than or equal to the distance K6 and less than twice the distance K6. In this way, the dimension X in the longitudinal direction of the transport vehicle 100 relative to the pallet P supported by the fork 15 is kept small.

[0046] In this embodiment, the distance K7 between the pair of legs 32 in the width direction Y is greater than the reference radius R1 and less than or equal to twice the reference radius R1. In this embodiment, the distance K8 between the pair of second wheels 12 in the width direction Y is greater than the reference radius R1 and less than or equal to twice the reference radius R1. In this embodiment, the distance K9 between the two outer ends 32a of the pair of legs 32 in the width direction Y is greater than the reference radius R1 and less than or equal to twice the reference radius R1.

[0047] In this embodiment, the front end T1a of the first wheel 11 in the turning trajectory T1 is positioned to fall within a region E1 within a reference radius R1 from the first turning axis C1. In this embodiment, the turning support 33 is positioned to fall within a region E1 within a reference radius R1 from the vehicle turning axis C2 when viewed in the vertical direction. In this embodiment, the pair of legs 32 and the pair of second wheels 12 are positioned to fall within a region E1 within a reference radius R1 from the vehicle turning axis C2 when viewed in the vertical direction.

[0048] In this embodiment, the drive unit 13 is positioned so that it is located within the region E1, which is within the reference radius R1 from the vehicle body pivot axis C2 when viewed from above. In this embodiment, the lifting device 20 is positioned so that it is located within the region E1, which is within the reference radius R1 from the vehicle body pivot axis C2 when viewed from above.

[0049] In this embodiment, the end portion T1a of the front X1 of the first wheel 11 in the second state is positioned to fall within the region E1 within the reference radius R1 from the first pivot axis C1. However, the end portion T1a of the front X1 of the first wheel 11 in the first and third states does not necessarily have to fall within the region E1 within the reference radius R1 from the first pivot axis C1.

[0050] The main body 31 is equipped with an anti-tipping support member 39. The anti-tipping support member 39 is positioned X1 in front of the first wheel 11. The anti-tipping support member 39 is positioned so as to be within a region E1 within a reference radius R1 from the vehicle body pivot axis C2 when viewed in the vertical direction. In this embodiment, a pair of anti-tipping support members 39 are provided. The pair of anti-tipping support members 39 are positioned on both sides in the width direction Y with respect to the pivot trajectory T1 of the first wheel 11.

[0051] In this embodiment, the anti-tipping support member 39 is positioned in front of the first wheel 11 in the first state (X1). Alternatively, the anti-tipping support member 39 may be positioned behind the end T1a of the front X1 of the first wheel 11 in the second state (X2).

[0052] In this embodiment, the anti-tipping support member 39 is a wheel. This reduces wear on the running surface. In this embodiment, the anti-tipping support member 39 does not come into contact with the running surface when the transport vehicle 100 is in motion. Note that the anti-tipping support member 39 may be an elastic member, a resin member, a cushioning member, etc., instead of a wheel.

[0053] Figure 5 is a front view showing an example of the counterweight 50 at the upper limit position. Figure 6 is a front view showing an example of the counterweight 50 at the lower limit position. Figure 7 is a side view showing an example of the counterweight 50 at the upper limit position. In this embodiment, the lifting device 20 is equipped with a counterweight 50. By providing the lifting device 20 with a counterweight 50, the driving force of the lifting drive source 25 can be kept low. Furthermore, because the lifting device 20 supported by the main body 31 is equipped with a counterweight 50, even when lifting a pallet P on which a heavy object is placed with the forks 15, the posture of the transport vehicle 100 can be easily stabilized by the main body 31 supported by the counterweight 50.

[0054] In this embodiment, the connecting member 27 connects the fork 15, the lifting drive device 24, and the counterweight 50. When the lifting device 20 raises the fork 15, the counterweight 50 lowers. When the lifting device 20 lowers the fork 15, the counterweight 50 rises.

[0055] Figure 8 shows an example of the upper surface of the counterweight 50. The counterweight 50 includes a pair of outer mounting parts 51 that are arranged on a first side Y1 and a second side Y2 in the width direction relative to a pair of guide rails 18. The counterweight 50 includes a connecting part 53 that connects the pair of outer mounting parts 51 in the width direction Y. In this embodiment, the connecting part 53 is arranged to pass through the front side X1 relative to the pair of guide rails 18.

[0056] Figure 9 shows an example of the upper surface of the swivel support section 33. The connecting section 53 is positioned so as to overlap with the swivel section 33a of the swivel support section 33 in a vertical view. In this embodiment, the vertical trajectory of the connecting section 53 is positioned above the swivel section 33a at Z1. The pair of outer arrangement sections 51 are positioned so as not to overlap with the swivel section 33a in a vertical view.

[0057] The connecting portion 53 is positioned so as to overlap with the wheel drive source 14 in a vertical view. The lifting trajectory of the connecting portion 53 is positioned above the wheel drive source 14 at Z1. In this embodiment, the pair of outer arrangement portions 51 are positioned so as not to overlap with the wheel drive source 14 in a vertical view.

[0058] The connecting portion 53 is positioned so as to overlap with the first wheel 11 in a vertical view. The lifting trajectory of the connecting portion 53 is positioned above the first wheel 11 by Z1. The pair of outer arrangement portions 51 are positioned so as not to overlap with the first wheel 11 in a vertical view. The lifting trajectory of the pair of outer arrangement portions 51 has a portion below the lifting trajectory of the connecting portion 53 by Z2.

[0059] In this embodiment, the travel drive unit 13 in the first and second states is positioned so as to overlap with the coupling portion 53 when viewed from above. However, at least one of the first wheel 11 and the travel drive unit 13 may be positioned so as to overlap with the coupling portion 53 when viewed from above in the first state, and so as not to overlap with the coupling portion 53 when viewed from above in the second state.

[0060] As shown in Figure 8, the pair of outer mounting sections 51 are positioned inward in the width direction Y from both outer ends 32a of the pair of leg sections 32 in the width direction Y. The pair of outer mounting sections 51 are positioned so as to overlap with the guide rail 18 when viewed in the width direction along the width direction Y.

[0061] As shown in Figure 5, the connecting section 53 includes an inner arrangement section 55 between a pair of guide rails 18 in the width direction Y. The connecting section 53 includes a pair of inner arrangement sections 55, which are arranged separately on the first side Y1 and the second side Y2 in the width direction relative to the lifting drive source 25. In this embodiment, the pair of outer arrangement sections 51 are each configured to have adjustable weight. In this embodiment, the pair of inner arrangement sections 55 are each configured to have adjustable weight.

[0062] As shown in Figure 8, the pair of outer arrangement parts 51, the connecting part 53, and the pair of inner arrangement parts 55 are arranged so that they fall within a region E1 within a reference radius R1 from the vehicle body pivot axis C2 when viewed in the vertical direction. In this embodiment, the entire counterweight 50 is arranged so that it falls within a region E1 within a reference radius R1 from the vehicle body pivot axis C2 when viewed in the vertical direction.

[0063] In this embodiment, the weight ratio of the pair of outer mounting parts 51 to the total weight of the counterweight 50 is configured or adjusted to be 50% or more. Preferably, the weight ratio of the pair of outer mounting parts 51 to the total weight of the counterweight 50 is configured or adjusted to be 60% or more. Even more preferably, the weight ratio of the pair of outer mounting parts 51 to the total weight of the counterweight 50 is configured or adjusted to be 70% or more.

[0064] As shown in Figure 8, the guide mechanism 22 includes a second guided member 22b which is connected to the counterweight 50 and guided along the vertical direction Z by the guide rail 18. In this embodiment, the second guided member 22b is supported by a connecting portion 53. The second guided member 22b may also be supported by an outer mounting portion 51 or an inner mounting portion 55. In this embodiment, the second guided member 22b is a roller.

[0065] In this embodiment, the guide mechanism 22 includes a pair of second guided members 22b connected to each of the pair of outer arrangement portions 51 and guided by each of the pair of guide rails 18. The pair of second guided members 22b are arranged to be in contact with each of the pair of guide rails 18 from the outside in the width direction Y relative to the pair of guide rails 18.

[0066] The transport vehicle 100 includes a control unit 60 which includes at least some of the equipment for controlling the travel drive unit 13 and the lifting device 20. The control unit 60 is positioned along the vertical Z and width Y directions. The control unit 60 is positioned in front of the pair of guide rails 18 by X1. The control unit 60 is positioned inward in the width Y direction from both outer ends 18a, which are the outermost ends of the pair of guide rails 18 in the width Y direction. In this embodiment, the control unit 60 is positioned so as to fall within a region E1 within a reference radius R1 from the vehicle body pivot axis C2 when viewed in the vertical direction.

[0067] As shown in Figures 5 and 6, the transport vehicle 100 is equipped with a power storage device 62 that supplies power to at least one of the travel drive unit 13 and the lifting device 20. The power storage device 62 is located below the control unit 60 at Z2. As shown in Figure 8, the power storage device 62 is positioned in a location that overlaps with the control unit 60 when viewed in the vertical direction.

[0068] As shown in Figure 8, the energy storage device 62 is positioned so as to overlap with the vertical trajectory of the connecting section 53 when viewed from above. The energy storage device 62 is positioned so as not to overlap with the vertical trajectories of the pair of outer arrangement sections 51. The energy storage device 62 is positioned so as to overlap with the vertical trajectories of the pair of outer arrangement sections 51 when viewed from the width direction Y or from the front-to-back direction X.

[0069] As shown in Figure 6, the energy storage device 62 is positioned such that its upper surface is below Z2 the lower limit of the vertical trajectory of the connecting portion 53. The energy storage device 62 is positioned such that its lower surface is above Z1 the lower limit of the vertical trajectory of the pair of outer arrangement portions 51.

[0070] As shown in Figure 6, the first wheel 11 is positioned so that it is below the lower limit Z2 of the lifting trajectory of the connecting section 53. The wheel drive source 14 is positioned so that its upper surface is below the lower limit Z2 of the lifting trajectory of the connecting section 53.

[0071] As shown in Figures 2 and 7, the lifting drive source 25 is positioned in front of the rail-to-rail arrangement section 15c X1. In this embodiment, the lifting drive source 25 is positioned so as to overlap with the control unit 60 when viewed in the vertical direction.

[0072] In this embodiment, the lifting drive source 25 is located in front of the connecting portion 53 X1. In this embodiment, the lifting drive source 25 is located in front of the pair of guide rails 18 X1.

[0073] As shown in Figure 1, the control unit 60 includes an input device 63 mounted on the transport vehicle 100. The input device 63 is located on the front X1 surface of the vehicle body 30. In this embodiment, the input device 63 mounted on the transport vehicle 100 is positioned so that, when viewed in the vertical direction, it is within a region E1 within a reference radius R1 from the vehicle body pivot axis C2. In the illustrated example, the input device 63 includes a monitor.

[0074] The transport vehicle 100 is equipped with a control unit accessory member 65 which is at least one of the following: wiring connected to the control unit 60 and connection terminals for the wiring connected to the control unit 60. In this embodiment, the control unit accessory member 65 is positioned so as to be within a region E1 within a reference radius R1 from the vehicle body pivot axis C2 when viewed in the vertical direction.

[0075] The control unit accessory member 65 is positioned in a region in the width direction Y that is inside the width direction Y beyond the outer ends 32a of the pair of legs 32 in the width direction Y. In this embodiment, the control unit accessory member 65 is positioned outside the width direction Y relative to the control unit 60, and in a region in the width direction Y that is inside the width direction Y beyond the outer ends 32a of the pair of legs 32 in the width direction Y.

[0076] The control unit accessory member 65 is positioned in a region in the front-rear direction X that is rearward X2 from the end 60a, which is the foremost end X1 of the control unit 60. In this embodiment, the control unit accessory member 65 is positioned in a region in the front-rear direction X that is rearward X2 from the end 60a of the front X1 of the control unit 60, and in front of the pair of guide rails 18.

[0077] As shown in Figure 1, the transport vehicle 100 is equipped with an obstacle sensor 71 that detects obstacles present around the vehicle body 30. The obstacle sensor 71 is positioned on the front X1-facing surface of the main body 31. In this embodiment, the obstacle sensor 71 is positioned so as to fall within a region E1 within a reference radius R1 from the vehicle body rotation axis C2 when viewed in the vertical direction.

[0078] As shown in Figure 2, the transport vehicle 100 is equipped with a pallet detection sensor 75 that detects whether or not a pallet P is supported at a reference position set on the fork 15. The pallet detection sensor 75 detects, for example, whether or not there is an object in contact with or close to the base end surface 15b of the fork 15, or whether or not there is an object in contact with the mounting surface of the fork 15 corresponding to the reference position, etc.

[0079] [Other Embodiments] Next, other embodiments of the transport vehicle 100 will be described.

[0080] (1) In the above embodiment, a configuration in which the position of the fork 15 in the longitudinal direction X relative to the vehicle body 30 is fixed was described as an example. However, the example is not limited to such an example, and for example, the fork 15 may be configured to be extendable and retractable in the longitudinal direction X.

[0081] (2) In the above embodiment, the main body 31 is provided with a swivel support 33, and the end T1a of the front X1 in the swivel trajectory T1 of the first wheel 11 is positioned to fall within a region E1 within a reference radius R1 from the first swivel axis C1. However, the embodiment is not limited to such an example, and for example, the end T1a of the front X1 in the swivel trajectory T1 of the first wheel 11 is not positioned to fall within a region E1 within a reference radius R1 from the first swivel axis C1. Also, for example, the main body 31 is not provided with a swivel support 33.

[0082] (3) In the above embodiment, a configuration in which the travel drive unit 13 is equipped with a pair of wheel drive sources 14 so that each of the pair of first wheels 11 can be driven independently was described as an example. However, the invention is not limited to such an example, and for example, the travel drive unit 13 may not be able to drive each of the pair of first wheels 11 independently. Also, for example, there may be only one wheel drive source 14 and the pair of first wheels 11 may be able to rotate in opposite directions to each other. Also, for example, the transport vehicle 100 may be equipped with only one first wheel 11.

[0083] (4) In the above embodiment, a configuration was described as in which the spacing K7 of the pair of legs 32 in the width direction Y is greater than the width direction Y dimension of the largest pallet, and the reference radius R1 is set based on the largest pallet. However, the invention is not limited to such an example, and for example, the reference radius R1 may be set based on the average value of multiple pallets P. Also, for example, the spacing K7 of the pair of legs 32 in the width direction Y may be the same as or less than the width direction Y dimension of the largest pallet.

[0084] (5) In the above embodiment, the main body 31 is provided with an anti-tipping support member 39, and the anti-tipping support member 39 is positioned in front of the first wheel 11 X1 as an example. However, the embodiment is not limited to such an example, and for example, the anti-tipping support member 39 may be positioned in rear of the first wheel 11 X2. Also, for example, the main body 31 may not be provided with an anti-tipping support member 39.

[0085] (6) In the above embodiment, a configuration was described as in which a pair of first guide members 22a are arranged to contact each of the pair of guide rails 18 from the inside in the width direction Y. However, the invention is not limited to such an example, and for example, a pair of first guide members 22a may be arranged to contact each of the pair of guide rails 18 from the outside in the width direction Y, the front side X1, the rear side X2, etc.

[0086] (7) In the above embodiment, a configuration was described as in which a pair of second guide members 22b are arranged to contact each of the pair of guide rails 18 from the outside in the width direction Y. However, the invention is not limited to such an example, and for example, a pair of second guide members 22b may be arranged to contact each of the pair of guide rails 18 from the inside in the width direction Y, from the front side X1, the rear side X2, etc.

[0087] (8) In the above embodiment, the lifting drive device 24 was described as being located above the lifting trajectory of the first guided member 22a Z1 and overlapping with the rail-to-rail arrangement portion 15c in a vertical view. However, the embodiment is not limited to such an example, and for example, the lifting drive device 24 may be located at a position that does not overlap with the rail-to-rail arrangement portion 15c in a vertical view. Alternatively, for example, the lifting drive device 24 may be located below the lifting trajectory of the first guided member 22a Z2.

[0088] (9) In the above embodiment, a configuration was described in which the connecting portion 53 of the counterweight 50 is arranged to pass through the front X1 with respect to the pair of guide rails 18. However, the invention is not limited to such an example, and for example, the connecting portion 53 may be arranged to pass through the inside of the pair of guide rails 18 in the width direction Y.

[0089] (10) In the above embodiment, the connecting portion 53 was described as being positioned so as to overlap with the first wheel 11 in a vertical view, and the lifting trajectory of the connecting portion 53 was positioned above the first wheel 11 in Z1. However, the embodiment is not limited to such an example, and for example, the connecting portion 53 may be positioned so as not to overlap with the first wheel 11 in a vertical view. Alternatively, for example, the connecting portion 53 may be positioned so as to overlap with the first wheel 11 in a view along the longitudinal direction X or the width direction Y.

[0090] (11) In the above embodiment, a configuration was described as in which the pair of outer arrangement parts 51 are arranged in a position that does not overlap with the first wheel 11 in a vertical view, and the lifting trajectory of the pair of outer arrangement parts 51 has a portion below the lifting trajectory of the connecting part 53 in Z2. However, the embodiment is not limited to such an example, for example, the pair of outer arrangement parts 51 may be arranged in a position that overlaps with the first wheel 11 in a vertical view. Also, for example, the lifting trajectory of the pair of outer arrangement parts 51 does not have to have a portion below the lifting trajectory of the connecting part 53 in Z2.

[0091] (12) In the above embodiment, the control unit accessory member 65 was described as being located outside the control unit 60 in the width direction Y, and inside the width direction Y of both outer ends 32a of the pair of legs 32, and inside the front-rear direction X of the control unit 60, X2 behind the end 60a of the front X1. However, the embodiment is not limited to such an example, and for example, the control unit accessory member 65 may be located inside the width direction Y of the control unit 60. Also, for example, the control unit accessory member 65 may be located outside the width direction Y of both outer ends 32a of the pair of legs 32. Also, for example, the control unit accessory member 65 may be located in front of the end 60a of the front X1 of the control unit 60.

[0092] (13) In the above embodiment, the configuration described as being in which the energy storage device 62 is located below the control unit 60 Z2 and overlaps with the control unit 60 in a vertical view was described as an example. However, the embodiment is not limited to such an example, and for example, the energy storage device 62 may be located above the control unit 60 Z1. Also, for example, the energy storage device 62 may be located in a position that does not overlap with the control unit 60 in a vertical view.

[0093] (14) In the above embodiment, a configuration in which the first guided member 22a and the second guided member 22b are rollers was described as an example. However, the embodiment is not limited to such an example, and for example, the first guided member 22a and the second guided member 22b may be sliding parts. Also, for example, the first guided member 22a and the fork 15 may be integrally configured.

[0094] (15) In the above embodiment, a configuration was described as in which the travel drive unit 13, the lifting device 20, the vehicle body 30, the counterweight 50, the control unit 60, the control unit accessory member 65, and the obstacle sensor 71 are arranged so that, in a vertical view, they fall within a region E1 within a reference radius R1 from the vehicle body pivot axis C2. However, the embodiment is not limited to such an example, and for example, one or more of the travel drive unit 13, the lifting device 20, the vehicle body 30, the counterweight 50, the control unit 60, and the obstacle sensor 71 do not have to be arranged so that, in a vertical view, they fall within a region E1 within a reference radius R1 from the vehicle body pivot axis C2.

[0095] (16) In the above embodiment, a configuration in which the main body 31 supports the lifting device 20, the first wheel 11, and the travel drive device 13 was described as an example. However, the invention is not limited to such an example, and for example, the legs 32 may support one or more of the lifting device 20, the first wheel 11, and the travel drive device 13. Also, for example, both the main body 31 and the pair of legs 32 may be formed in an arc shape when viewed in the vertical direction, so that the vehicle body 30 is formed in a C shape when viewed in the vertical direction.

[0096] (17) In the above embodiment, a configuration in which the transport vehicle 100 is equipped with forks 15 that support the pallet P has been described as an example. However, the invention is not limited to such an example, and for example, instead of the forks 15, a pallet support part such as a crane arm or a robot arm may be used, which is arranged to protrude toward the rear X2 from the lifting device 20 and support the pallet P. Alternatively, for example, the lifting device 20 may be a device that raises and lowers a pallet support part such as a crane arm or a robot arm.

[0097] (18) The configurations disclosed in the embodiments described above can be applied in combination with configurations disclosed in other embodiments, as long as they do not cause any inconsistencies. 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.

[0098] [Summary of the above embodiments] The transport vehicle related to this disclosure will be described below.

[0099] In one embodiment, the transport vehicle comprises a fork that supports a pallet, a lifting device for raising and lowering the fork, a first wheel that rotates around a first rotation axis, a pair of second wheels that rotate around a second rotation axis, a drive device that drives at least one of the first wheel and the pair of second wheels, and a vehicle body that supports the lifting device, the drive device, the first wheel, and the pair of second wheels, wherein a specific direction along the horizontal plane is defined as the front-rear direction, a direction along the horizontal plane that is perpendicular to the front-rear direction is defined as the width direction, one side in the front-rear direction is defined as the front side, the other side in the front-rear direction is defined as the rear side, one side in the width direction is defined as the first width direction side, and the other side in the width direction is defined as the second width direction side, and the fork protrudes from the lifting device toward the rear side. The vehicle body is arranged in such a manner that it comprises a main body and a pair of legs arranged to protrude from the main body toward the rear on the first and second sides in the width direction relative to the lifting trajectory of the forks, with the pair of legs supporting each of the pair of second wheels, the second rotation axis is a rotation axis along the width direction, and the axis passing through the midpoint of the pair of second wheels on the second rotation axis and along the vertical direction is the vehicle body pivot axis, and the radius determined based on the distance between the furthest end of the pallet supported at a reference position set on the forks and the vehicle body pivot axis is used as the reference radius, and the vehicle body is formed so that, in a vertical view, it fits within the area from the vehicle body pivot axis to the reference radius.

[0100] With this configuration, the vehicle body is formed so that, when viewed from above, it fits within a region within the reference radius from the vehicle's pivot axis. Therefore, the area required for the transport vehicle to turn can be easily kept small. Consequently, it is easy to travel in narrow areas.

[0101] In one embodiment, the position of the fork in the front-rear direction relative to the vehicle body is fixed.

[0102] This configuration eliminates the need for a structure that moves the forks in the front-to-back direction relative to the vehicle body, making it easier to miniaturize the transport vehicle. Furthermore, it allows for a reduction in the front-to-back dimensions of the transport vehicle.

[0103] In one embodiment, the main body includes a pivot support portion that pivotably supports the first wheel around a first pivot axis along the vertical direction, and the front end of the pivot trajectory of the first wheel is positioned to fall within a region within the reference radius from the vehicle pivot axis.

[0104] With this configuration, the entire turning trajectory of the first wheel falls within a region within the reference radius from the vehicle's turning axis, making it easier to keep the area required for the transport vehicle to turn small.

[0105] In one embodiment, the main body includes a swivel support that supports a pair of first wheels so as to be rotatable around a first pivot axis along the vertical direction, and the running drive device includes a pair of wheel drive sources that can drive each of the pair of first wheels independently.

[0106] With this configuration, the driving force of the pair of first wheels can be controlled independently, making it easier to perform smooth turning movements of the transport vehicle. Furthermore, the movement of turning the pair of first wheels around the first pivot axis can be performed, for example, using a drive unit that drives the first wheels.

[0107] In one embodiment, there are multiple types of pallets with different dimensions, the distance between a pair of legs in the width direction is greater than the width direction dimension of the largest pallet, and the reference radius is set based on the largest pallet.

[0108] This configuration allows for the proper transport of multiple types of pallets.

[0109] In one embodiment, the main body is equipped with a support member for preventing tipping, and the support member for preventing tipping is positioned in front of the first wheel.

[0110] This configuration reduces the possibility of the transport vehicle tipping forward due to vibrations of the vehicle body while in motion or vibrations of the floor surface while stationary.

[0111] The transport vehicle relating to this disclosure only needs to be able to achieve at least one of the effects described above. [Explanation of Symbols]

[0112] 11:1st wheel 12: 2nd wheel 13: Driving system 14: Wheel drive source 15: Fork 20: Lifting device 30: Vehicle body 31: Main body 32: Legs 33: Swivel support section 39: Support member for preventing tipping 100: Transport vehicle A1: First rotation axis A2: 2nd rotation axis center C1: 1st rotation axis center C2: Vehicle rotation axis E1: area P: Palette R1: Reference radius T1: Turning trajectory T1a: Front end of the turning trajectory

Claims

1. Forks to support the pallet, A lifting device for raising and lowering the fork, A first wheel that rotates around the first axis of rotation, A pair of second wheels that rotate around a second axis of rotation, A running drive device that drives the first wheel and at least one of the pair of second wheels, The lifting device, the driving device, the first wheel, and the vehicle body supporting the pair of second wheels, A transport vehicle equipped with, A specific direction along the horizontal plane is defined as the front-rear direction, a direction along the horizontal plane that is perpendicular to the front-rear direction is defined as the width 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, one side of the width direction is defined as the first width direction side, and the other side of the width direction is defined as the second width direction side. The fork is positioned to protrude from the lifting device toward the rear. The vehicle body comprises a main body and a pair of legs arranged to protrude from the main body toward the rear on the first and second sides in the width direction with respect to the lifting trajectory of the fork. The pair of legs support each of the pair of second wheels, The second rotation axis is a rotation axis that lies along the width direction, and the axis passing through the midpoint of the pair of second wheels on the second rotation axis and lies along the vertical direction is the vehicle body pivot axis. The radius determined based on the distance between the end of the pallet supported at a reference position set on the fork and the vehicle body pivot axis, and the vehicle body pivot axis, A transport vehicle in which the vehicle body is formed such that, when viewed from above, it fits within the area of ​​the vehicle body's pivot axis and the reference radius.

2. The transport vehicle according to claim 1, wherein the position of the fork in the front-rear direction relative to the vehicle body is fixed.

3. The main body includes a swivel support that supports the first wheel so as to be rotatable around a first pivot axis along the vertical direction, The transport vehicle according to claim 1, wherein the front end of the first wheel in the turning trajectory is positioned to fall within a region within the reference radius from the axis of rotation of the vehicle body.

4. The main body includes a swivel support that supports a pair of the first wheels so as to be rotatable around a first pivot axis along the vertical direction, The transport vehicle according to claim 1, wherein the transport drive device comprises a pair of wheel drive sources so that each of the pair of first wheels can be driven independently.

5. The transport vehicle according to any one of claims 1 to 4, wherein the pallets are of multiple types with different dimensions, the distance between a pair of legs in the width direction is greater than the width direction dimension of the largest pallet, which is the largest pallet, and the reference radius is set based on the largest pallet.

6. The transport vehicle according to any one of claims 1 to 4, wherein the main body is equipped with a support member for preventing tipping, and the support member for preventing tipping is positioned in front of the first wheel.

7. The transport vehicle according to any one of claims 1 to 4, wherein the reference radius is a radius determined based on the distance between the end of the pallet, which is supported at a reference position set on the fork and whose widthwise dimension is smaller than the widthwise separation distance of a pair of legs, and the vehicle's pivot axis.

8. The transport vehicle according to any one of claims 1 to 4, wherein the distance between the pair of legs in the width direction is greater than the reference radius and less than or equal to twice the reference radius.

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