JPH0137301B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an unmanned transport vehicle for transporting vehicles such as passenger cars.

Normally, vehicles that are being assembled and have wheels and other underbody parts attached to them are transported by a slat conveyor and subjected to various processing, but due to the relationship with sub-lines, processing stations, etc. Since it is not possible to perform all processing on a single processing line, processing, inspection, and transportation are performed on multiple lines that are independent of each other. Conventionally, when conveying vehicles between these mutually separated lines, an overhead conveyor was used, but when using an overhead conveyor, the end of the previous slat conveyor and the following A transfer device for transferring vehicles to and from the overhead conveyor is required at each starting end of the slat conveyor of the tier, which not only complicates the overall configuration of the device but also increases cost. There were problems such as poor workability.

By the way, vehicles that are currently being assembled and have wheels and other undercarriage parts installed, and vehicles that have completed the installation of transported parts, are transported on the same plane as the floor surface, so there is no space between the slat conveyors on each assembly line. Now, it is thought that the above-mentioned problem can be solved by towing the vehicle and driving it on the floor surface. In that case, since the steering device of the vehicle itself cannot be automatically operated, it is preferable to use an unmanned transport vehicle that tows the vehicle with at least the front wheels lifted off the floor. In this case, the situation is very different from the case where an unmanned guided vehicle runs alone, and it is difficult to use the unmanned guided vehicle that has been used in various fields as is.

That is, FIGS. 1 to 3 are schematic plan views showing conventional unmanned guided vehicles. The unmanned guided vehicle 1 shown in FIG. The provided front wheel 3 is a driven wheel and is configured to be able to turn in any direction by a steering motor 4, and the rear wheel 5, which is a driving wheel, is driven by a differential gear 7 by a driving motor 6. The main body 2 is configured to rotate forward and backward through the main body 2, and a lifter 8 is provided in the center of the main body 2. Further, the unmanned carrier vehicle 10 shown in FIG. 2 is of a six-wheel type, and
Driven wheels 12 are rotatably provided on both left and right sides at both front and rear ends of the main body 11, and drive wheels 14a and 14b, which are rotated individually by traveling motors 13a and 13b, are located at the center of the book 11. A lifter 15 is provided on both the left and right sides, and a lifter 15 is provided in the center of the main body 11, and the vehicle is configured to curve in either direction due to the difference in rotational speed between the left and right drive wheels 14a, 14b. . The unmanned carrier vehicle 20 shown in FIG. 3 is of a four-wheel type, and two wheels provided on either the left or right sides of the main body 21 are driven wheels 22a, 22b. is configured to be able to turn freely, and the other two wheels are driven by driving motors 23a, 23.
Drive wheels 24a, 24b rotated by b,
These drive wheels 24a, 24b are configured to individually turn in any direction by steering motors 25a, 25b, and a lifter 26 is provided in the center of the main body 21.

When transporting the vehicle 30 with the front wheels 31 of the vehicle 30 floating by the unmanned transport vehicle 1 shown in FIG. If the configuration is such that it cannot rotate relative to 2, the unmanned guided vehicle 1 and the vehicle 30 are substantially integrated, and the 5 wheels that contact the floor, that is, the front and rear wheels 3, 5 of the unmanned guided vehicle 1
And since only the front wheels 3 of the automatic guided vehicle 1 turn among the rear wheels 32 of the vehicle 30, no matter how the front wheels 3 turn, the extension line of the axle of each wheel 3, 5, 32 is one point. In other words, the instantaneous centers do not become one, so it is not possible to run on a curve. On the other hand, if the vehicle receiving part of the lifter 8 is made rotatable, the unmanned carrier vehicle 1 and the vehicle 30 can be kept substantially separated when traveling on a curve, which eliminates the above-mentioned disadvantages. It can be resolved. However, when traveling in a curve instead of straight, the front wheels 3 are turned once to rotate the unmanned carrier 1 relative to the vehicle 30 until the necessary turning radius is obtained, and then the extension line of the rear wheel axle of the vehicle 30 is It is necessary to adjust the turning angle of the front wheels 3 so that the extension line of the front wheel axle of the unmanned carrier vehicle 1 intersects with the extension line of the rear wheel axle of the unmanned carrier vehicle 1. In addition, when traveling in a straight line from traveling on a curve, the front wheels 3 of the unmanned carrier vehicle 1 are once turned significantly in the opposite direction to the forward direction to make the unmanned carrier vehicle 1 parallel to the vehicle 30, and then the front wheels 3 are returned to the straight traveling state. There is a need. In this way, when traveling from a straight line to traveling on a curve, and vice versa, it is necessary to rotate the unmanned guided vehicle 1 by a large amount relative to the vehicle 30. There is a risk of interference, and as a result, the turning radius must be increased, and the required floor area must be increased accordingly. There is a problem that the process becomes complicated and driving stability is impaired. Furthermore, when the vehicle receiving portion of the lifter 8 is made rotatable, it is necessary to provide a rotation prevention mechanism to restrict the rotation of the vehicle receiving portion in order to ensure stability when loading and unloading the vehicle 30.
Considering that the total height of the unmanned carrier 1 must be set to be lower than the minimum ground clearance of the vehicle 30 because the unmanned carrier 1 needs to fit under the vehicle 30, the overall configuration of the unmanned carrier 1 is extremely complicated. At the same time, this increases the cost, and furthermore, there is a risk that reliability in terms of strength and durability may decrease.

On the other hand, a conventional unmanned carrier vehicle 1 having the configuration shown in FIG.
0, if the vehicle receiving part is fixed,
Since the resistance force when rotating the unmanned guided vehicle 10 relative to the vehicle 30 becomes extremely large, it is difficult to run the unmanned carrier vehicle 10 only by the difference in rotation between the left and right drive wheels 14a, 14b. On the other hand, if the vehicle receiving part is configured to be rotatable, the unmanned carrier vehicle 10 can be easily rotated relative to the vehicle, but the drive wheels 14a can be adjusted so that the travel radius when traveling on a curve becomes the desired radius. , 14b to cross the extension line of the rear wheel axle of the vehicle 30 at a predetermined position, it is difficult to set the difference in rotational speed between the drive wheels 14a and 14b, and extremely complicated control is required. It will stop happening. Furthermore, since the unmanned carrier vehicle 10 shown in FIG.
In order to balance the load applied to the lifter 14b, it is difficult to incorporate the lifter 15 and the rotating mechanism for the vehicle receiving portion into the center of the main body 11, which may make the overall configuration extremely complicated and difficult to manufacture. be.

Moreover, the unmanned carrier 20 having the configuration shown in FIG.
Since all of the wheels are configured to be able to rotate independently, the unmanned carrier 2 can be easily rotated without making the vehicle receiving part particularly rotatable.
0 and the entire vehicle 30 can be set at one point, and there is sufficient space in the center of the main body 21, even if the lifter 26 is provided in the center of the main body 21, the structure will not be particularly complicated. That's not it. However, on the other hand, each drive wheel 24a, 24b
Since the configuration is such that the turning angle of the vehicle 30 is individually controlled, when traveling in a curve, the extension line of each drive wheel axle is made to intersect at one point on the extension line of the rear wheel axle of the vehicle 30, that is, the instantaneous center is at one point. Each drive wheel 24
It is difficult to control the turning angles of a and 24b, resulting in a complicated control system and high cost.

This invention was made in view of the above-mentioned circumstances, and provides a vehicle that has a simple configuration, is capable of running on smooth curves, and furthermore, can easily lower its overall height than the minimum ground clearance of the vehicle to be transported. The purpose is to provide an unmanned transport vehicle for transportation. The features of this invention are as follows:
The vehicle has a three-wheel configuration, with one wheel provided at the front end or rear end of the main body serving as a driving wheel, and the driving wheel is turned by a steering mechanism so as to travel along a predetermined path. year,
In addition, there are other two
The wheels are driven wheels, each driven wheel is configured to be able to turn freely, and furthermore, a fixing mechanism is provided to fix each driven wheel in a straight running state when traveling with the end where the driven wheel is provided as the front, and also The main body is equipped with a lifting device that lifts up the front end of the vehicle to be transported and lifts the front wheels off the running surface.

Embodiments of the present invention will be described below with reference to FIGS. 4 to 7.

FIG. 4 is a partially cutaway schematic side view showing an embodiment of the present invention, and FIG. 5 is a partially cutaway schematic side view showing an unmanned carrier 40 shown here.
One driving wheel 42 is provided at one of the front and rear ends of the main body 41, and two driven wheels 43a, 43b are provided at the other end.
It is said to be a three-wheeled model with a In the following description, the driving wheel 42 side is assumed to be a front end, and the driven wheels 43a, 43b side are assumed to be a rear end. A turning table 44 is attached to the lower surface of the center of the front end of the main body 41 so as to be rotatable about a rotating shaft 45, and a driving wheel 42 is attached to the center of the lower surface of the turning table 44 via a bearing member 46. The drive wheel 42 is connected to a traveling motor 47 attached to a bearing member 46. Teeth are formed on the outer periphery of the rotating table 44 and mesh with a steering gear 49 rotated by a steering motor 48 attached to the main body 41. Therefore, the driving wheels 42 are rotated by the steering motor 48. Rotating table 4 via steering gear 49
It is configured so that the direction can be changed in any direction by turning 4. That is, the steering motor 48, steering gear 49, and turning table 44 constitute a steering mechanism. Note that the steering mechanism only needs to have a configuration that can change the direction of the driving wheels 42, and in addition to the mechanism shown in the figure, it may also be configured by, for example, a plurality of links, or a combination of links and links. It may also be configured in combination with a slider that reciprocates in one direction.

On the other hand, the driven wheels 43a, 43b are provided on both left and right sides of the lower surface of the rear end of the main body 41, and these driven wheels 43a, 43b are connected to the rotating shafts 50a, 50b.
It is rotatably attached to the main body 41 via pivot plates 51a and 51b that pivot around the center. That is, the rotation center axis of each driven wheel 43a, 43b is
Since the grounding point is located slightly away from the axes of the rotating shafts 50a and 50b, which are the turning centers, and the grounding point is away from the turning center axis, the resistance force generated at the grounding point during running becomes turning torque, and the As a result, each of the driven wheels 43a, 43b is configured to automatically change direction in the running direction.

In addition, when the rear end side where the driven wheels 43a, 43b are provided is in the forward direction, if the driven wheels 43a, 43b are in a state where they can freely turn, the resistance of the driven wheels 43a, 43b at the time of startup is large; In addition, since the direction of travel is not determined when driving, the driven wheels 43a, 43
A fixing mechanism is provided to fix the vehicle b in a straight running state. That is, cutouts 52a and 52b are formed on the outer peripheries of the rotating plates 51a and 51b, and these cutouts 52a and 52b face toward the front end of the main body 41 when the driven wheels 43a and 43b are in the straight-ahead state shown in FIG. On the other hand, a lock bar 53 is provided on the front end side of the main body 41 rather than the pivot plates 51a, 51b so as to be movable back and forth, and the lock bar 53 is fitted into the notches 52a, 52b.
4a and 54b are provided on the lock bar 53. A cam 56 is rotated by a lock motor 55 on the front end side of the lock bar 53, that is, on the opposite side to the protrusions 54a and 54b of the lock bar 53.
is arranged, and the lock bar 53 is connected to the cam 5.
6 and moves toward the rotating plates 51a and 51b,
As a result, the protrusions 54a, 54b are cut out from the notch 52.
By fitting into a, 52b, the driven wheel 43
a, 43b are fixed in a straight running state. Although not specifically shown, the lock bar 53 is pressed toward the cam 56 by an elastic body such as a spring, and when the lock motor 55 is not operating, the lock bar 53 is pulled away from the rotating plates 51a, 51b to open the protrusions 54a, 54b. Notch 53a,
53b.

In addition, in the center of the main body 41, there is a vehicle 3 to be transported.
A lifting device 57 is provided to push up the front end of the 0. Its configuration is shown in FIG. That is, the lifting device 57 is connected to the vehicle receiving plate 59 by two links 58a and 58b that are crossed and pinned together.
The lower end of one link 58a is rotatably attached to the main body 41, and the upper end is rotatably attached to the lower surface of the vehicle receiving plate 59. An internally threaded member 6 whose upper end portion of the other link 58b engages with the lower surface of the vehicle receiving plate 59 so as to be movable along the surface direction, and whose lower end portion is threadedly engaged with the feed screw shaft 60.
It is rotatably attached to 1. Therefore, the lifting device 57 connects the feed screw shaft 61 with the lifting motor 62.
By rotating the female screw member 61 back and forth, the vehicle receiving plate 59 is connected to the links 58a, 5.
It is configured to be raised and lowered via 8b.

Furthermore, the main body 41 has a battery 63 as a power source.
, and a control device 64 that controls forward and backward movement, ascent and descent of the elevating device 57, and the like.

Next, a control system configuration for operating the unmanned carrier vehicle 40 will be explained.

A forward guide wire 66 and a backward guide wire 67 are buried in the floor 65 on which the unmanned carrier vehicle 40 runs, and a forward detector 68 detects the electromagnetic plate emitted by the forward guide wire 66. A reverse detector 69 is attached to the lower surface of the turning table 44, more precisely in front of the drive wheels 42, and detects electromagnetic waves emitted by the reverse guide wire 67.
It is attached to the center of the lower surface of the rear end. Each of the guide wires 66 and 67 is configured to be turned on and off by a ground platform 70, and each of the detectors 68 and 6
9 inputs the output signal to the control device 64, and operates the steering motor 48 based on the output signal from the control device 64, thereby creating guide lines 66, 67 that always correspond to when moving forward or backward. It is positioned above the . In other words, when moving forward, the forward guide line 6
6, and when reversing, use the reversing guide line 67.
It is designed to run along the A frequency detector 71 connected to the control device 64 is attached to a predetermined location on the lower surface of the main body 41, and in response to a command signal from the ground platform 70, a travel start signal of a predetermined frequency and a lift start signal of a different frequency are generated. The transmitting antennas 72a and 72b that transmit signals are the seventh
It is installed at a location corresponding to the frequency detector 71 at loading position A and unloading position B shown in the figure. Furthermore, a magnetic detector 73 for stopping is attached to a predetermined location on the lower surface of the main body 41, and a magnet 74 is attached to the lower surface of the main body 41.
a, 74b are provided at locations corresponding to the magnetic detectors 73 at the loading position A and the unloading position B, and the magnetic detectors 73 are provided at locations corresponding to the magnetic detectors 73 at the loading position A and the unloading position B,
By detecting the magnetism emitted by the motor 4b, a stop signal is output to the control installation 64, and as a result, the travel motor 47 is stopped. Further, a stop confirmation electromagnet 75 and a lift confirmation electromagnet 76, which are excited and demagnetized by the control device 64, are each attached to a predetermined location on the lower surface of the main body 41, and each electromagnet 75, 76 is energized and demagnetized. Stop confirmation magnetic detectors 77a, 77b and lift confirmation magnetic detector 78 that output signals to the ground platform 70
a and 78b are provided at locations corresponding to the electromagnets 75 and 76 at the loading position A and the unloading position B, respectively.

At the loading position A and the unloading position B, there are limit switches 79 and 8 for detecting the presence or absence of the vehicle 30.
0 is provided, and when the limit switch 79 at the loading position A is on and the limit switch 80 at the unloading position B is off, the ground platform 7
The unmanned carrier vehicle 40 is operated by the output signal from 0, and the unmanned carrier vehicle 40 is not operated in the opposite case. In addition, the reference numeral 81 in FIG. 7 is a magnet placed just before the unloading position B, and when the unmanned carrier vehicle 40 is traveling forward, its magnetic detector 73 detects magnetism, and the unmanned carrier vehicle 40 is moved forward. 40
It is configured to slow down the

When transporting the vehicle 30 using the device configured as described above, the unmanned carrier 40 is stopped at a loading position A, which is the terminal end of a slat conveyor (not shown). In this state, the magnetic detector 73 is sensitive to the magnet 74a installed on the floor 65, and as a result, the traveling motor 47 is stopped, and the stop confirmation electromagnet 75 is energized, and the stop confirmation magnetic detector 77a is accordingly energized. is outputting a signal to the ground platform 70. In this state, the vehicle 30 is conveyed by the slat conveyor, and when its front end, for example, the front axle, reaches above the lifting device 57, the limit switch 79 is turned on and outputs a signal to the ground platform 70. The transmission antenna 72a outputs a signal of a predetermined frequency that raises the lifting device 57 in response to a command signal from the ground platform 70. The frequency detector 71 of the unmanned carrier 40 detects the signal, and the control device 64 detects the signal.
By outputting a signal to , the elevating motor 62 is activated, and as a result, the vehicle receiving plate 59 rises, pushing up the front end of the vehicle 30 and separating the front wheels 31 from the floor 65 . Then, the stop confirmation electromagnet 75 is demagnetized and the lift confirmation electromagnet 76 is energized by an output signal from a limit switch (not shown) or the like that detects that the lift device 57 has reached the rising end. An elevation confirmation magnetic detector 78a sensitive to the magnetism outputs a signal to the ground platform 70. The ground platform 70 that receives the signal from the lift confirming magnetic detector 78a causes the transmission antenna 72a to output a signal of a predetermined frequency instructing to start the travel motor 47 in the forward direction, while energizing the forward guide wire 66. . Frequency detector 71 detects the signal output from transmitting antenna 72a
outputs a signal to the control device 64, and as a result, the travel motor 47 rotates in the forward direction according to the output signal from the control device 64, and the unmanned carrier 40 moves toward the vehicle 30.
The vehicle moves forward while being towed by pushing up the front end of the vehicle. In that case, each magnet 75, 76 is demagnetized, and the fixing mechanism is in a non-operating state, so that the driven wheel 4
3a and 43b are in a state where they can freely rotate.

When the unmanned guided vehicle 40 starts traveling, the forward detector 68 detects the electromagnetic waves emitted by the forward guide wire 66, and an output signal from the control device 64 causes the forward detector 68 to always follow the guide wire. 66
While appropriately turning the turning table 44 by the steering motor 48 so as to be positioned above the
That is, the vehicle runs while controlling the direction of the drive wheels 42,
Therefore, the unmanned carrier 40 travels along the forward guide line 66. When the unmanned guided vehicle 40 starts traveling in a curved line from a straight line as shown by the solid line in FIG.
Since the driven wheels 43a and 43b can turn freely, the driving wheels 43a and 43b automatically turn in the direction in which the forces acting as they travel are balanced, and as a result, the driving wheels 42 The instantaneous center of each driven wheel 43a, 43b coincides with a point 0 on the extension line of the rear wheel axle of the vehicle 30, so the unmanned carrier 40 and the vehicle 30 smoothly curve around the point 0. do. Further, in that case, since the unmanned carrier 40 does not change its direction significantly with respect to the vehicle 30, there is no risk that the unmanned carrier 40 will interfere with the front wheels 31 of the vehicle 30.
There is no need to push up the front end of the 0 particularly high.

On the other hand, when traveling in a curve changes to traveling in a straight line, the driving wheels 42 are returned to a straight traveling state by the steering motor 48, and the driven wheels 43a, 43b automatically change their direction to travel in a straight line. It is possible to smoothly start running in a straight line without once changing the direction of the vehicle 30 significantly with respect to the vehicle 30.

When the unmanned carrier 40 passes the magnet 81, the magnetism is detected by the magnetic detector 73.
detects and outputs a signal to the control device 64, and as a result, the rotational speed of the travel motor 47 is reduced and decelerated. When the unmanned carrier 40 reaches the unloading position B in a decelerated state, that is, the starting end of the other slat conveyor (not shown), the magnetic detector 73 detects the magnetism of the magnet 74b provided on the floor 65 at the unloading position B. By detecting and outputting a signal to the control device 64, the traveling motor 47 is stopped by the output signal from the control device 64, and the unmanned carrier vehicle 40 is stopped at the unloading position B. At the same time, the stop confirmation electromagnet 75 is excited, and the output signal from the stop confirmation magnetic detector 77b by detecting the magnetism causes the ground platform 70 to stop energizing the forward guide wire 66 and stop the lifting device 57. A signal of a predetermined frequency to be lowered is output from the transmitting antenna 72b. When the frequency detector 71 detects the transmitted signal, the control device 64 gives a signal to the lifting motor 62 to start it, and as a result, the lifting device 57 moves downward and the vehicle 30 is moved to the unloading position B side. It is lowered onto the slat conveyor. When the lifting device 57 reaches the lower end, an output signal from a limit switch (not shown) or the like operates to change the operating mode in the control device 64 from forward to backward, and at the same time, the lifting confirmation electromagnet 76 is excited and the stop confirmation electromagnet 75 is activated. is demagnetized. Further, when the driving mode changes to reverse, the lock motor 55 operates, and the lock bar 53 is pushed by the cam 56 to move the rotating plate 51 to which the driven wheels 43a and 43b are attached.
Since the protrusions 54a and 51b move toward the sides a and 51b, the protrusions 54a and
54b fits into notches 53a, 53b formed in the rotating plates 51a, 51b, and as a result, the driven wheels 43a, 43b are fixed in a straight traveling state.

On the other hand, the ground platform 70 energizes the reversing guide wire 67 based on the output signal from the elevating/lowering confirmation magnetic detector 78b which detects the magnetism emitted by the elevating/lowering confirming electromagnet 76, and sends a predetermined signal to instruct the unmanned carrier vehicle 40 to travel backwards. Output the frequency signal from the transmitting antenna 72b,
As a result, the frequency detector 7 installed on the unmanned carrier 40
1 detects the signal output from the transmitting antenna 72b, and the traveling motor 47 begins to rotate in the backward direction. Then, the steering motor 48 is controlled by the output signal from the control device 64 when the reverse detector 69 detects the electromagnetic waves emitted by the reverse guide wire 67, and as a result, the automatic guided vehicle 40 moves toward the reverse guide wire 67. drive along. In that case, since the driven wheels 43a and 43b are fixed in a straight-ahead running state, even if the driven wheels 43a and 43b side are on the forward side, only the direction of the driving wheel 42 on the rear side in the running direction is controlled. Unmanned transport vehicle 40
The vehicle accurately travels straight and curves along the reverse guide line 67. Note that even when traveling backwards, the unmanned carrier vehicle 40 passes the magnet 81 provided on the floor 65 for deceleration, and the magnetic detector 73 detects the magnetism, but the driving mode in the control device 64 is set to the backward mode. Therefore, the unmanned carrier vehicle 40 travels backwards without decelerating.

When the unmanned carrier 40 reaches the loading position, the magnetism of the magnet 74a provided on the floor 65 is detected by the magnetic detector 7.
3 is detected, the unmanned carrier vehicle 40 stops. Then, the stop confirmation electromagnet 75 is energized, the operation mode in the control device 64 is switched to the forward mode, and the lock motor 55 operates in the opposite manner to the case described above to release the fixation of the driven wheels 43a, 43b. On the other hand, the ground platform 70 stops energizing the reverse guide wire 67 based on the output signal from the stop confirmation magnetic detector 74a by detecting the magnetism of the stop confirmation electromagnet 75. Therefore, the unmanned transport vehicle 40 returns to its original state and thereafter operates in the same manner as described above.

Note that when the unmanned carrier vehicle 40 starts traveling, each electromagnet 75, 76 is demagnetized, and the output from the transmitting antennas 72a, 72b is accordingly stopped. Furthermore, if the preceding vehicle 30 is present at the unloading position B, the limit switch 80 is turned on, so the unmanned carrier vehicle 40 does not operate.

As is clear from the above description, according to the present invention, the wheel structure is a three-wheel structure, one wheel provided at the front end or the rear end of the main body is used as a drive wheel, and the drive wheel is routed along a predetermined path. A fixing mechanism that fixes each driven wheel in a straight-line state when the vehicle is driven with the other end provided at the rear end or the front end of the main body as the front. In addition, the main body is equipped with a lifting device that lifts up the front end of the vehicle to be transported and lifts its front wheels off the running surface, so if the direction of the drive wheels is changed to drive around a curve while the vehicle is being transported, , the driven wheels automatically turn so that the instantaneous centers of the driving wheels and the driven wheels coincide at a point on the extended line of the rear wheel axle of the vehicle being transported, thus allowing smooth curved travel. . In addition, in that case, all you have to do is turn the drive wheels to follow a predetermined travel route, so control for driving around a curve is extremely simple, and when changing from driving in a straight line to driving around a curve, or vice versa. Furthermore, since there is no need to change the direction of the vehicle significantly, there is no risk of interference with the front wheels of the vehicle, and therefore there is no need to make the lifting stroke of the lifting device particularly high. Therefore, according to the present invention, not only can the configuration of the control device be simplified, but also there is no need to make the lifting device or its vehicle receiving portion rotatable, and its upward stroke can be reduced. Because it is low, the elevating device itself can have a simple configuration, which in turn simplifies the overall configuration of the unmanned transport vehicle, making it possible to easily set its overall height to below the minimum ground clearance of the vehicle.
Furthermore, it can be made inexpensive.

[Brief explanation of drawings]

1 to 3 are schematic plan views showing conventional unmanned carriers, FIG. 4 is a partially cutaway schematic plan view showing an embodiment of the present invention, and FIG. 5 is a partially cutaway schematic side view. FIG. 6 is a schematic diagram of the elevating device, and FIG. 7 is a layout diagram of members such as guide wires installed on the floor. 30...Vehicle, 31...Front wheel, 32...Rear wheel,
40...Unmanned carrier, 41...Main body, 42...Drive wheel, 43a, 43b...Driver wheel, 44...Swivel table, 47...Travel motor, 48...Steering motor, 49...Steering gear ,5
1a, 51b...Swivel plate, 52a, 52b...Notch, 53...Lock bar, 54a, 54b...
Projection, 55... Lock motor, 56... Cam, 5
7... Lifting device, 64... Control device.

Claims (1)

[Claims] 1. A single driving wheel provided on one of the front end or rear end of the main body, a driven wheel rotatably provided on both left and right sides of the other front end or rearward end of the main body, and a predetermined drive wheel. a steering mechanism that rotates the drive wheels around a vertical axis so as to travel along a route; a fixing mechanism that fixes the driven wheels in a straight-line state when traveling with the end where the driven wheels are provided as the front; 1. An unmanned carrier for transporting vehicles, characterized in that the vehicle is equipped with a lifting device that pushes up the front end of the vehicle to separate the front wheels of the vehicle from the running surface.