JPH08258763A - Article conveying vehicle - Google Patents

Abstract

PURPOSE: To perform stable ground support of a conveying vehicle by means of a number of earth wheels as the earth wheel is prevented from levitation and besides to reduce the change of the earth attitude of a conveying car body due to a conveyance weight. CONSTITUTION: At least one spot A1 of three earth support positions A1, A2, and A3 in which earth support of a conveying car body 1 is effected is caused to effect earth support by a wheel support body 3 to support earth wheels 2a, 2b, and 2c in three support positions B1, B2, and B3, equivalent to the apex positions of a virtual triangle Q in a plane view. The wheel support body 3 is oscillatorily mounted on the conveying car body 1 side in such a state to allow relative rotation around virtual line segments D1, D2, and D3, which intercouple the remaining two support positions of three support positions B1, B2, and B3, in such a state that earth support of two spots A2 and A3, except the earth support position A1, is effected by the wheel support body 3. The operation center position of a load exerted on the wheel support body 3 by the conveying car body 1 side is arranged inside a virtual triangle Q.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an article transport vehicle in which three ground support positions for supporting a transport vehicle body via ground wheels are located at three vertexes of a virtual triangle in plan view.

[0002]

2. Description of the Related Art In the article transport vehicle, since the transport vehicle body is ground-supported via ground wheels at three ground-supporting positions corresponding to the vertex positions of a virtual triangle in plan view, the transport vehicle body is uneven. Although there is an advantage that the vehicle can be stably supported on the ground even on a running surface, it is desirable to support the vehicle body on the ground by as many ground wheels as possible while preventing the ground wheels from being lifted up in order to increase the transport weight.

[0003] Therefore, conventionally, although the ground support is not provided at three ground support positions arranged on the transport vehicle, the ground wheels, which are biased by springs so as to move relative to the traveling surface side, are provided on the transport vehicle. It has been proposed to provide a large number of ground wheels to prevent the ground wheels from being lifted up while supporting the vehicle body on the ground with these ground wheels.

[0004]

According to the above-mentioned prior art, the amount of expansion and contraction of the spring for urging the grounding wheel changes depending on the size of the carrying weight and the distribution of the carrying weight on the carrying vehicle body. Since the relative position in the up and down direction with respect to the transport body of the vehicle changes, even if the traveling surface is flat,
There is a drawback that the ground posture of the transport vehicle body is likely to change. In particular, in an article transport vehicle that automatically loads and unloads articles, there is a drawback that it is difficult to perform the work smoothly if the ground posture of the transport vehicle body changes during the loading and unloading of articles.

The present invention has been made in view of the above circumstances, and by devising a ground support structure for a transport vehicle body, the transport vehicle body is stably grounded by a large number of ground wheels while preventing the ground wheel from rising. An object of the present invention is to provide an article transport vehicle which can be supported and in which the change in the ground posture of the transport vehicle body due to the transport weight is small.

[0006]

According to a first characteristic configuration of the present invention for achieving the above object, a ground support position for supporting a transport vehicle body on the ground via ground wheels is located at a vertex position of a virtual triangle in plan view. It is an article transporting vehicle arranged at three corresponding positions, and at least one of the three ground supporting positions has a ground supporting position corresponding to three vertex positions of a virtual triangle in plan view. It is supported on the ground by a wheel support that supports a ground wheel at a position, and the wheel support is supported on the transport vehicle body at two positions other than the ground support position where the wheel support supports the ground. While the position is supported to the ground, each of the three bearing positions is swingably attached while allowing relative rotation around a virtual line segment connecting the remaining two bearing positions, From the vehicle body side to the wheel support Action center position of the load to use is in that the bearing position of the three positions in a plan view are arranged on the inner side of the imaginary triangle corresponding to the vertex position.

A second characteristic configuration of the present invention is the first characteristic configuration according to the first characteristic configuration, wherein the wheel support is supported on the transport vehicle body side such that both ends thereof are vertically swingable about a first swing axis. A moving member and a second swinging end of the first swinging member, the both ends of which are swingably supported around a second swinging axis in a direction intersecting the first swinging axis. A rocking member is provided, and the ground wheels are supported at three bearing positions of the other rocking end side of the first rocking member and the left and right rocking end sides of the second rocking member. There is a point.

A third characteristic construction of the present invention is the grounding construction according to the first or second characteristic construction, wherein the ground support is supported at two bearing positions arranged in the vehicle body width direction among the three bearing positions of the wheel support. A drive device for driving the wheels so that the peripheral speed can be relatively changed is provided, and all the ground wheels other than the ground wheels that can be driven and rotated by the drive device are rotatably supported around the vertical axis. is there.

According to a fourth characteristic configuration of the present invention, in the third characteristic configuration, the wheel support is rotatably supported around the vertical axis center with respect to the transport vehicle side, and the wheel support is supported by the vertical axis. The point is that a drive device that is driven and rotated around the core is provided.

A fifth characteristic configuration of the present invention is that, in the third or fourth characteristic configuration, the grounding wheel which can be driven and rotated by the drive unit is arranged at a substantially central position in the vehicle front-rear direction.

[0011]

The operation of the first characteristic structure is as follows. Ground support positions for supporting the transport vehicle body on the ground via the ground wheels are arranged at three positions corresponding to the vertex positions of the virtual triangle in a plan view, and at least one of the ground support positions is a virtual triangle in the plan view. It is supported on the ground by wheel supports that support ground wheels at three support positions corresponding to the apex position, and the center of action of the load acting on the wheel support from the transport vehicle side is three support positions in plan view. Since the position is arranged inside the virtual triangle corresponding to the apex position, the transport vehicle body is supported on the ground by the grounding wheels supported at least at five points on the running surface having no unevenness.

Further, the wheel supports having the grounding wheels supported at the three support positions have two ground support positions other than the ground support position supported by the wheel support on the ground with respect to the transport vehicle body side. While it is supported on the ground, it is mounted so that each of the three bearing positions can be swung freely around the imaginary line segment connecting the remaining two bearing positions. Even if there is unevenness on the surface, each of the grounding wheels supported at the three bearing positions moves relative to the transport vehicle side so as to follow the unevenness of the running surface, and the bearings at the three locations are supported. Each of the ground wheels supported in the position is maintained in a grounded state.

The movement of the three support positions of the wheel support will be described with reference to FIGS. 3 (a), 3 (b) and 3 (c). Incidentally, in FIG. 3, the carrier body 1 is connected to the ground wheels 2a,
Ground support positions A1, A2, A3 for ground support via 2b, 2c, 2d, 2e are arranged at three positions corresponding to the vertex positions of the virtual triangle P in plan view, and the ground support positions A1, at these three positions. One ground support position A1 of A2 and A3 corresponds to the apex position of the virtual triangle Q in plan view 3
At the bearing positions B1, B2, B3 of the places, the ground wheels 2a, 2
b, 2c are supported to the ground by the wheel support 3 which supports,
The wheel support 3 is swingably attached to the vehicle body 1 via a universal joint 15, and two ground support positions A2 other than the ground support position A1 supported by the wheel support 3 on the ground.
With A3 supported to the ground, three bearing positions B1, B
2 schematically shows an article transport vehicle that allows relative rotation around virtual line segments D1, D2, D3 connecting the remaining two bearing positions of each of B2 and B3.

FIG. 3A shows a series of flat running surfaces G.
1, three support positions B1, B2, B of the wheel support 3 are provided.
Grounding point C of grounding wheels 2a, 2b, 2c supported on No. 3
1, C2, C3 and two ground support positions A2 other than the ground support position A1 supported by the wheel support 3 on the ground.
Grounding point C of grounding wheels 2d and 2e supporting A3 to the ground
Fig. 3 shows a state in which 5 points of 4 and C5 are grounded.
(B) is an uneven running surface in which any two of the ground contact points C1, C2, C3 on the wheel support 3 side, for example, only four contact points C1, C2 and ground contact points C4, C5 are uneven. FIG. 3C shows a state of being grounded to G2.
All of C2 and C3 and all five points of grounding points C4 and C5 are in contact with the uneven running surface G2.

Then, as shown in FIG. 3 (a), the article transport vehicle traveling on the flat traveling surface G1 with all the ground contact points C1, C2, C3, C4 and C5 being in contact with the ground travels unevenly. When traveling on the surface G2, the transport vehicle body 1 is supported on the ground at three ground support positions A1, A2, A3, and therefore, at least one of the ground contact points C1, C2, C3, for example, the ground contact point C1. It is assumed that the three ground points C4 and C5 are grounded and the ground points C2 and C3 are levitated from the uneven running surface G2.

In this state, since the load W acts on the wheel support 3 from the side of the carrier body 1, the bearing position B1 is the bearing position with the grounding point C1 being grounded, as indicated by the arrow in the figure. As a result of relative rotation around a virtual line segment D1 connecting B2 and B3, each of the floating ground contact points C2 and C3 moves to the uneven running surface G2 side.

Any one of the ground points C2 and C3
When a point, for example, a ground contact point C2 is grounded on the uneven running surface G2 as shown in FIG. 3B, the bearing position B3 is a virtual line segment connecting the bearing positions B1 and B2 as indicated by the arrow in the figure. D
By rotating around 3, the remaining floating ground contact point C3 moves to the uneven running surface G2 side and contacts the uneven running surface G2 as shown in FIG. 3C.

That is, two ground support positions A2, A3 other than the ground support position A1 supported by the wheel support 3 on the ground.
While supporting the ground to the ground, each of the three bearing positions B1, B2, B3 of the wheel support 3 is relatively rotated around the virtual line segments D1, D2, D3 connecting the remaining two bearing positions. Since it is allowed, ground points C1, C2, C3 and ground point C
All four points, C4 and C5, are in contact with the uneven running surface G2.

The operation of the second characteristic structure is as follows. The first rocking member is first rocked while the relative positions of the three ground bearing support positions of the first rocking member and the left and right ground wheel supporting positions of the second rocking member are fixed. When it is swung about the axis of motion, the grounding wheel bearing position of the first rocking member turns around an imaginary line segment connecting the left and right grounding wheel bearing positions of the second rocking member, and While the relative position between the two bearing positions of the grounding wheel bearing position of the first rocking member and the left or right grounding wheel bearing position of the second rocking member is fixed, When each of the second rocking members is rocked around the first rocking axis and the second rocking axis, the other grounding wheel bearing position of the second rocking member becomes
It rotates about an imaginary line segment connecting the grounding wheel bearing position of the first rocking member and one grounding wheel bearing position of the second rocking member.

The operation of the third characteristic structure is as follows. Since a drive device for driving the ground wheels supported at two bearing positions arranged side by side in the vehicle width direction so that the peripheral speed can be relatively changed is provided, the ground wheels supported at the two bearing positions can be used. When driving at different peripheral speeds,
When the transport vehicle starts turning, all of the ground wheels other than the ground wheels that can be driven and rotated by the drive device are rotatably supported around the vertical axis core. All of the ground wheels rotatably supported around the core rotate so as to face the turning direction of the transport vehicle body.

The operation of the fourth characteristic structure is as follows. When the wheel support is driven and rotated about the vertical axis with respect to the transport vehicle body side, the orientation of the ground wheels supported at two bearing positions arranged in the vehicle body width direction with respect to the transport vehicle body side is changed. When the ground wheels supported at two bearing positions are driven by, the carrier body starts traveling in the direction of those ground wheels, and as the carrier body starts traveling, it rotates around the vertical axis. All of the ground wheels which are freely supported rotate so as to face the traveling direction of the carrier body.

The operation of the fifth characteristic structure is as follows. Since the ground wheels that can be driven and rotated to change the traveling direction of the transport vehicle body are arranged at substantially the center position in the vehicle front-rear direction, there is little difference between the steering operation characteristics when moving forward and the steering operation characteristics when moving backward.

[0023]

According to the first characteristic configuration, even if the traveling surface has irregularities, the transport vehicle body is supported at at least five places without providing the grounding wheel urged to relatively move toward the traveling surface side. Since the grounded wheels can be ground-supported, the grounded wheels can be prevented from floating, and the grounded wheels can be stably grounded by a large number of grounded wheels, and the ground posture of the carrier body is not significantly changed due to the transport weight.

According to the second characteristic construction, the first swinging member and the second swinging member are connected to the transport vehicle body side in order so as to be swingable in a simple structure, and the ground wheels are supported at three places. Since each of them can be rotated around an imaginary line segment connecting the remaining two bearing positions, the wheel support body in which the three bearing positions are relatively fixed is connected via a universal joint such as a ball joint. As compared with the case where the carriage is mounted on the side of the carrier body and each of the three bearing positions is rotated around an imaginary line segment connecting the remaining two bearing positions, such a universal joint is not particularly required, It is easy to attach the wheel support to the transport vehicle side easily.

According to the third characteristic configuration, when the ground wheels supported at the two support positions are driven at different peripheral speeds, the transport vehicle body starts to turn, and when the transport vehicle body starts to turn, the vertical shaft is moved. Since all of the ground wheels rotatably supported around the core rotate so as to face the turning direction of the transport vehicle, the transport vehicle can be smoothly turned with a small turning radius.

According to the fourth characteristic configuration, when the traveling direction of the transport vehicle body is changed, it is easy to orient all of the ground wheels in the traveling direction in which the vehicle body is to be changed. The turning motion is unlikely to occur, and there is little risk that the article placed on the transport vehicle body is swung in the horizontal direction.

According to the fifth characteristic configuration, since there is little difference between the steering operation characteristic when moving forward and the steering operation characteristic when moving backward, the steering operation is easy.

1 and 2 show an article transport vehicle which is automatically guided by a guideway 4 buried in a traveling surface G in an automated warehouse or the like. The article transport vehicle is energized to the guideway 4. The magnetic field generated with this and the electromagnetic induction action of the pickup coil 5 provided on the side of the article transport vehicle drive the electric motors M1 and M2 by the electromotive force generated in the pickup coil 5 so that the electric motors M1 and M2 travel.

The article transport vehicle is controlled so that a pallet containing articles is loaded and automatically transported to a predetermined station, and is automatically stopped at a station located in the middle of the traveling route, so that the pallet is transported to the transport vehicle body 1. The article carrier that has been automatically loaded by the provided conveyor 6 and has completed loading the pallets starts automatic running and automatically stops at the target station, and the loaded pallets are automatically unloaded by the conveyor 6. Is done.

The transport vehicle body 1 has a virtual triangle P in a plan view.
Ground support positions A arranged at three locations corresponding to the apex position of
1, A2, A3 to ground wheels 2a, 2b, 2c, 2d, 2
Ground support via A, and these three ground support positions A
One of the ground support positions A1 on the front side of the vehicle body out of 1, A2, A3 corresponds to the three support positions B1, B2, B3 corresponding to the apex positions of the virtual triangle Q in plan view, and the ground wheels 2a,
It is supported on the ground by a wheel support 3 which supports 2b and 2c.

With respect to the side of the transport vehicle body 1, the wheel support 3 has both ends along the vehicle body front-rear direction around the first swing axis E1 parallel to the vehicle body width direction on the bracket 7 fixed to the transport vehicle body 1. The first swinging member 8 supported so as to swing vertically and the swinging end side of the first swinging member 8 on the rear side of the vehicle body intersect at a right angle with the first swinging axis E1 at the center position in the vehicle body width direction. Direction, that is,
A second swinging member 9 is provided, both ends of which are supported around the second swing axis E2 parallel to the vehicle body front-rear direction so as to be vertically swingable along the vehicle body width direction.

The wheel support 3 is provided at a bearing position B1 arranged on the swing end side of the first swing member 8 on the front side of the vehicle body.
And three bearing positions B1, B2, which are respectively the bearing positions B2, B3 arranged on the left and right swing end sides of the second swing member 9.
The ground wheels 2a, 2b, 2c are supported on B3, and two ground support positions A2, A3 other than the ground support position A1 supported on the ground by the wheel support 3 are grounded to the transport vehicle 1 side. Relative rotation around virtual line segments D1, D2, D3 connecting the remaining two bearing positions of each of the three bearing positions B1, B2, B3 while supporting the ground through 2d, 2e. The center of action of the load W acting on the wheel support 3 from the side of the transport vehicle body 1 is swingably attached in a permissible state, and three bearing positions B1, B2, B3 correspond to apexes in plan view. It is arranged inside the virtual triangle Q.

A bearing position B1 arranged on the swinging end side of the first swinging member 8 on the front side of the vehicle body is a caster attached to the first swinging member 8 so as to be rotatable about a vertical axis F. It is arranged at a position displaced in the radial direction from the vertical axis F of the wheel support frame 10 of the structure.
1, a small diameter free-wheeling ground wheel 2a is rotatably supported around a horizontal axis, and the support positions B2 and B3 on the left and right swing ends of the second swing member 9 are substantially at the center in the vehicle body front-rear direction. It is arranged at two positions lined up in the vehicle width direction at these positions, and the bearing positions B2, B3
A large-diameter drive grounding wheel 2b, 2c is rotatably supported on each of these wheels.

Each of the drive ground wheels 2b and 2c has
Electric motors M1 and M2 capable of rotating in the forward and reverse directions are separately provided as drive devices for driving and rotating the drive ground wheels 2b and 2c, and by rotating the electric motors M1 and M2 at different rotational speeds, These drive ground wheels 2
The peripheral speeds of b and 2c are configured to be relatively changeable.

The above-mentioned three ground support positions A1, A2, A
Two ground support positions A2 and A on the rear side of the vehicle body out of three
Each of 3 is similar to the support position B1 of the first swing member 8,
The vertical axis F of the wheel support frame 10 of the caster structure mounted rotatably around the vertical axis F of the transport vehicle body 1.
From the ground support positions A2 and A3, which are arranged at positions displaced in the radial direction from each other and have small diameters.
Is rotatably supported around the horizontal axis.

Therefore, the idle grounding wheels 2 other than the driving grounding wheels 2b and 2c driven and rotated by the electric motors M1 and M2.
All of a, 2d, and 2e are rotatably supported on the transport vehicle body 1 about a vertical axis F, and drive ground wheels 2b and 2c.
When the transport vehicle body 1 starts to turn as the vehicle is driven at different peripheral velocities, all the idle ground wheels 2a, 2d, 2e turn so as to face the turning direction of the transport vehicle body 1. 1 can be smoothly turned with a small turning radius.

[Second Embodiment] FIG. 4 shows an embodiment in which the wheel support 3 is rotatably supported around the vertical axis V with respect to the transport vehicle body 1 side, and the bracket 7 is a transport vehicle body 1. With respect to the vertical axis V, a drive device that is rotatably attached around the vertical axis V and that drives and rotates the wheel support 3 around the vertical axis V makes it possible to relatively change the peripheral speed of the driving ground wheels 2b and 2c. The electric motors M1 and M2 that can be rotated forward and backward are also used. Other configurations are the same as in the first embodiment.

Therefore, when the driving ground wheels 2b and 2c are driven and rotated in the opposite directions at the same circumferential speed, the wheel support 3
Rotates around the vertical axis V with respect to the transport vehicle body 1 side, the orientation of the drive grounding wheels 2b, 2c with respect to the transport vehicle body 1 side is changed, and the drive grounding wheels 2b, 2c are directed in a predetermined traveling direction. When the drive ground wheels 2b and 2c are driven and rotated in the same direction in this state, the transport vehicle body 1 starts traveling in the direction of the drive ground wheels 2b and 2c, and the transport vehicle body 1
As the running of the vehicle starts, the idle grounding wheels 2a, 2d, 2
All of e are rotated so as to face the traveling direction of the transport vehicle body 1.

[Third Embodiment] FIG. 5 shows ground support positions A1, A2 and A3 for supporting the carrier body 1 on the ground via the ground wheels 2a, 2b, 2c, 2d and 2e. Of the three ground support positions A1, A2, and A3, which are on the front side of the vehicle body and are supported on the ground in the same manner as in the first embodiment. The ground support positions A2 and A3 are grounded by the wheel support 11 which supports the ground wheels 2d and 2e at three support positions J1, J2 and J3 corresponding to the vertex positions of the virtual triangle R in plan view. 1 illustrates a supported article transport vehicle.

Ground support positions A2 and A3 on the rear side of the vehicle body
The wheel support 11 for supporting each of them on the ground is provided with three support positions J1, that is, the swing end side of the first swing member 12 on the vehicle body front side and the left and right swing end sides of the second swing member 13. It has a structure similar to that of the wheel support 3 that ground-supports the ground support position A1 on the front side of the vehicle body in that the ground wheels 2d and 2e are supported on J2 and J3, but three support positions J1 and J2 are provided. , J3 are attached to the corresponding first and second swinging members 12, 13 in a radial direction from the vertical axis F of the wheel support frame 14 of the caster structure which is rotatably attached about the vertical axis F. It is placed in a position displaced to the
In addition, small diameter ground contact wheels 2d and 2e are rotatably supported around the horizontal axis. According to this embodiment, the transport vehicle body 1 can be ground-supported by the grounding wheels 2a, 2b, 2c, 2d, 2e which are supported at nine bearing positions B1, B2, B3, J1, J2, J3. Other configurations are the same as in the first embodiment.

[Other Embodiments] 1. A wheel support in which at least one of the three support positions of the wheel support is supported, and further, the grounding wheels are supported at three support positions corresponding to the vertex positions of the virtual triangle in plan view. You may implement in the form of supporting to the ground. 2. The wheel support may be configured by providing a second swinging member that can swing up and down around the second swinging axis in the direction inclined to the first swinging axis. 3. A wheel support whose three bearing positions are relatively fixed to each other is attached to the transport vehicle body side through a universal joint such as a ball joint, and the wheel support is swung at the universal joint. Around the imaginary line segment connecting the remaining two bearing positions of each of the three bearing positions of the wheel support, while still supporting the two ground supporting positions other than the ground supporting position supported by May be configured to allow relative rotation of the. 4. The drive device for driving and rotating the wheel support rotatably supported around the vertical axis with respect to the transport vehicle body may be provided separately from the drive device for traveling.

It should be noted that although reference numerals are given in the claims for convenience of comparison with the drawings, the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a side view of an article transport vehicle.

FIG. 2 is a plan view of an article carrier.

FIG. 3 is a schematic diagram of an article transport vehicle.

FIG. 4 is a side view of the article transport vehicle showing the second embodiment.

FIG. 5 is a plan view of an article transporting vehicle showing a third embodiment.

[Explanation of symbols]

 1 Transport Vehicle 2a, 2b, 2c, 2d, 2e Grounding Wheel 3 Wheel Support 8 First Swiveling Member 9 Second Swiveling Member A1, A2, A3 Ground Support Position B1, B2, B3 Bearing Position D1, D2, D3 Virtual line segment E1 First swing shaft core E2 Second swing shaft core F Vertical shaft core M1, M2 Drive device P Virtual triangle Q Virtual triangle V Vertical shaft core W Load

Claims (5)

[Claims] 1. A grounding wheel (2a, 2a) for a carrier body (1).
b, 2c, 2d, 2e), the ground support positions (A1, A2, A3) for ground support are arranged at three positions corresponding to the vertex positions of the virtual triangle (P) in plan view. Of the three ground support positions (A1, A2, A3), at least one ground support position (A1) corresponds to three vertex positions of the virtual triangle (Q) in plan view. Ground wheels (2a, 2b, 2) at the bearing positions (B1, B2, B3)
c) is supported by a wheel support (3) supporting the ground, and the wheel support (3) is supported by the wheel support (3) with respect to the transport vehicle body (1) side. With the two ground support positions (A2, A3) other than the ground support position (A1) being ground-supported, each of the three support positions (B1, B2, B3),
A virtual line segment (D1, D2, which connects the remaining two bearing positions)
D3) It is swingably attached in a state in which relative rotation around the D3) is allowed, and the action center position of the load (W) acting on the wheel support body (3) from the transport vehicle body (1) side is a plan view. In the article transport vehicle, the three bearing positions (B1, B2, B3) are arranged inside the virtual triangle (Q) corresponding to the vertex positions. 2. A first rocking member (8), wherein both ends of the wheel support (3) are vertically swingably supported around the first rocking axis (E1) on the side of the transport vehicle body (1). ) And a second swing axis (E2) in a direction intersecting the first swing axis (E1) on one swing end side of the first swing member (8).
A second swinging member (9) whose both ends are swingably supported up and down, and the other swinging end side of the first swinging member (8) and the second swinging member. (9) Grounding wheels (2a, 2b, 2c) at three bearing positions (B1, B2, B3) on the left and right swing end sides.
The article carrier according to claim 1, wherein the article carrier is supported. 3. A grounding wheel supported at two bearing positions (B2, B3) arranged in the width direction of the vehicle body among the three bearing positions (B1, B2, B3) of the wheel support (3). Grounding wheels other than the grounding wheels (2b, 2c) which are provided with driving devices (M1, M2) for driving (2b, 2c) so that the peripheral speed can be relatively changed, and which can be driven and rotated by the driving devices (M1, M2). The article transport vehicle according to claim 1 or 2, wherein all of (2a, 2d, 2e) are rotatably supported around a vertical axis (F). 4. The wheel support (3) is rotatably supported around the vertical axis (V) with respect to the transport vehicle body (1) side, and the wheel support (3) is attached to the vertical axis (3). 4. The article transport vehicle according to claim 3, further comprising drive devices (M1, M2) that are driven and rotated around (V). 5. The article transport vehicle according to claim 3 or 4, wherein the ground wheels (2b, 2c) that can be driven and rotated by the drive unit (M1, M2) are arranged at a substantially central position in the longitudinal direction of the vehicle body.