JP2000351385A - Automatically guided vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable an automatically guided vehicle to run over a level difference. SOLUTION: This automatically guided vehicle 1 is provided at each of a front and a rear with a single steering type drive wheel 3 and caster type driven wheels 4 are situated on both sides in the rear of a drive wheel 3 on the front side and at the front of a drive wheel 3 on the rear side with the drive wheel 3 nipped therebetween. The drive wheel 3 and the driven wheel 4 are suspended in a seesaw-like state at a wheel frame 5 pivotally supported in the middle in a longitudinal direction. The drive wheel side of the wheel frame is energized in a lifting up direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a factory or a warehouse.
A trackless automatic guided vehicle (A) that transports goods unmannedly
GV, automatic guided vehicle).

[0002]

2. Description of the Related Art AGV is used as a component of a transport system for automating the transport of parts, workpieces, products, etc. in production factories and warehouses. used. The AGV is a bogie that uses a storage battery as a power source, travels while automatically steering a traveling road surface by unmanned guidance, and transports a load as instructed. There are various types of AGV wheel arrangements and steering systems. For example, a tricycle type in which the front wheels drive and steer, each of which has independent drive wheels on the left and right of the center of the vehicle body, steers according to the difference in rotational speed of each wheel, and the front and rear wheels are one or two wheels with casters. Two-wheel speed difference steering type, front and rear two wheels on one side drive and steer independently, the other two front and rear wheels are wheels with casters, front and rear independent drive independent steering type, all four wheels drive and steer independently. All-wheel drive all-wheel steering type.

One of the AGV formats is as follows. 3 is a side view conceptual diagram of the AGV described here, FIG. 4 is a bottom view conceptual diagram, FIG. 5 is a plan view of the wheel suspension mechanism, and FIG. 6 is a side view of the wheel suspension mechanism. In these figures, reference numeral 1 denotes an automatic guided vehicle. Arrow A indicates the traveling direction of the automatic guided vehicle 1. The automatic guided vehicle 1 can travel in the opposite direction if the drive wheels are reversed, in which case the front and rear are reversed. The front and rear centers of the automatic guided vehicle 1 are each provided with one steering-type drive wheel 3.
In front of the front drive wheel 3 and in front of the rear drive wheel 3, caster driven wheels 4 are provided on both sides of the drive wheel 3 with the drive wheel 3 interposed therebetween. And is suspended in a seesaw shape on a wheel frame 5 pivoted at the position. Reference numeral 8 denotes a straight line connecting the front and rear drive wheels 3, 3, which coincides with the center line of the vehicle body. In addition, drive wheel 3
May be offset right and left as indicated by the dash-dot line in FIG. 8x is a straight line connecting the drive wheels before and after the offset.

Reference numeral 2 denotes a seesaw-shaped wheel suspension mechanism. The wheel suspension mechanism 2 has a wheel frame 5 as shown in FIGS. 5 and 6, and the wheel frame 5 is pivotally supported by a pin 6 provided on the vehicle body 1a in the middle in the front-rear direction. The steering drive wheels 3 provided in front of or behind the wheel frame 5 will be described. A turntable 3f fixed to the lower end of the vertical rotating shaft 3g is provided in front of or behind the wheel frame 5. The drive motor 3b is supported by a bracket (not shown) hanging from the turntable 3f.
The wheel 3a is fixed to. Reference numeral 3c denotes a steering motor. A pinion 3e is fixed to the steering motor 3c, and meshes with a gear carved on the outer periphery of the turntable 3f. The wheels 3a are driven by a driving motor 3b, and when the driving wheels 3 are located at the center between the front and rear, the wheels 3a are steered left and right through a turntable 3f within a range of 90 ° each. When the drive wheels 3 are offset, the steering is performed within a range of 90 ° left and right with respect to the straight line 8x. The caster driven wheels 4 are provided with two wheels 4a in parallel with each caster 4b. Reference numeral 7 denotes a stopper, which regulates a large movement of the seesaw of the wheel frame 5.

[0005] The automatic guided vehicle 1 travels straight if the direction of the drive wheels 3 is parallel to the center line of the vehicle body 1a. If the direction of the driving wheel 3 is tilted by 90 ° in the same direction with respect to the center line, the vehicle runs in the opposite direction. Will spin. When the driving wheel 3 is offset, if the driving wheel 3 is tilted by 90 degrees with respect to the straight line 8x, the spinning is performed on the spot.

[0006]

Such an automatic guided vehicle 1 basically travels on a flat floor.
It may be necessary to drive over a step as low as 1 cm. Drive wheels 3
And the driven wheels 4 easily get over, but the rear driven wheels 4
When a vehicle hits a step, a force acting on the driven wheel from the step when the vehicle rides over the step generates a moment in a direction (clockwise in FIG. 3) in which the drive wheel 3 is pushed up around the pin 6 on the wheel frame 5. The rear driving wheel 3 is in a floating state, the driving force in the forward direction is reduced to half, and the vehicle cannot travel. To prevent this, countermeasures such as increasing the diameter of the driven wheel 4 and lowering the position of the pin 6 are conceivable, but are often impractical due to restrictions such as the size of the vehicle body 1a and the mounting space.

The present invention has been devised in view of the above-mentioned problems of the prior art, and has as its object to provide an automatic guided vehicle that can travel even when there is a step on a traveling path.

[0008]

According to a first aspect of the present invention, there is provided an automatic guided vehicle having one steering wheel on each of front and rear sides, and a rear and rear drive of a front drive wheel. In front of the wheels, caster driven wheels are provided on both sides of the driving wheels, and the driving wheels and the driven wheels are suspended in a seesaw shape on a wheel frame pivotally supported in the middle in the front-rear direction. In a car, the driven wheel side of a wheel frame is urged in a lifting direction.

Further, the automatic guided vehicle according to the second aspect of the present invention,
It has a steering wheel of one wheel each in the front and rear, behind the front drive wheel and in front of the rear drive wheel, sandwiching the drive wheel,
On both sides thereof, caster type driven wheels are provided, and the drive wheel and the driven wheel are pushed down on the drive wheel side of the wheel frame in an automatic guided vehicle suspended in a seesaw shape on a wheel frame pivotally supported in the middle of the front-rear direction. It is the one that was urged.

Next, the operation of the present invention will be described. In the automatic guided vehicle according to the first aspect of the present invention, when the vehicle travels over a step during traveling, the rear driven wheel hits the step, and the moment applied around the pin of the wheel frame by the force applied to the rear driven wheel from the step causes the driving wheel to move. Even in the direction in which the driven wheels are lifted, the driven wheels of the wheel frame are urged in the direction of lifting by the springs, so that the moment in the direction in which the drive wheels are lifted is canceled. Therefore, the driving force is maintained as it is, and the rear driven wheel can easily get over the step, and even if there is a step, the automatic guided vehicle does not become unable to travel.

[0011] If the lifting force of the spring is too large, the driven wheels will rise even during traveling on a flat floor, and the automatic guided vehicle will become unstable.
Consider the diameter of the driven wheel, the position of the pin, etc., and select the spring with the minimum necessary strength.

In the automatic guided vehicle according to the second aspect of the present invention, on the contrary to the above, a heavy wheel or the like is attached to the drive wheel side of the wheel frame to prevent the drive wheel from floating. The relationship of the moments is the same as that of the first aspect of the present invention, and a detailed description is omitted.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic side view of the automatic guided vehicle according to the first aspect of the present invention. In FIG. 1, the same portions as those described in FIGS. 3 to 6 are denoted by the same reference numerals, and redundant description will be omitted. FIG.
In the figure, reference numeral 10 denotes a tension spring that urges the driven frame 4 of the wheel frame 5 in a direction of lifting the driven wheel 4. 11 is step 1
It is a floor surface having 1a. 11b is a corner of the step 11a.

Next, the operation of the present embodiment will be described. When the automatic guided vehicle 1 gets over the step 11a while traveling, the front drive wheel 3 and the driven wheel 4 easily get over. The rear follower wheel 4 hits the step 11a, and the corner 11 of the step 11a
The force indicated by arrow B is applied to the rear driven wheel 4 from b. The direction of the force B is a force directed toward the center 4c of the driven wheel 4, and generates a moment in a direction (clockwise in FIG. 1) in which the drive wheel 3 is lifted around the pin 6 of the wheel frame 5. A force in the direction of floating on the wheel 3 acts. However, due to the weight of the driving wheel 3, a moment is generated in the wheel frame 5 in the direction of pushing the driving wheel 3 around the pin 6 (counterclockwise in FIG.
, A moment in the same direction is generated by the force shown in (1), so that the moment in the counterclockwise direction exceeds the moment in the clockwise direction, so that the driving wheel 3 does not float. Therefore, the rear driving wheel 3 also keeps driving force, and the rear driven wheel 4 can get over the step 11a,
Thereafter, the rear drive wheel 3 also climbs over the step 11a.

FIG. 2 is a schematic side view of the automatic guided vehicle according to the second aspect of the present invention. In the present invention, unlike the automatic guided vehicle described with reference to FIG. 1, instead of the tension springs 10, the gravitational force 1 urges the drive wheels 3 of the wheel frame 5 in the pushing direction.
2 are provided. However, the relationship of the moment around the pin 6 of the wheel frame 5 is the same as that of the first aspect of the present invention, and therefore, duplicate detailed description will be omitted. It should be noted that a compression spring may be used instead of the heavy stone 12.

The present invention is not limited to the embodiment described above, and various changes can be made without departing from the gist of the invention.

[0017]

As described above, the automatic guided vehicle according to the present invention urges the driven wheel side of the wheel frame in the lifting direction or pushes the driving wheel side of the wheel frame in the pushing down direction. When the vehicle approaches a step on the floor, the rear driven wheel is stuck on the step and the automatic guided vehicle can travel over the step on the floor without being unable to run.

[Brief description of the drawings]

FIG. 1 is a schematic side view of an automatic guided vehicle according to the first aspect of the present invention.

FIG. 2 is a schematic side view of the automatic guided vehicle according to the second aspect of the present invention.

FIG. 3 is a schematic side view of a conventional automatic guided vehicle.

FIG. 4 is a bottom view of a conventional automatic guided vehicle.

FIG. 5 is a plan view of a wheel suspension mechanism.

FIG. 6 is a side view of the wheel suspension mechanism.

[Explanation of symbols]

 Reference Signs List 1 automatic guided vehicle 2 wheel suspension mechanism 3 drive wheel 4 driven wheel 5 wheel frame 6 pin

Claims (2)

[Claims] Claims: 1. A front-rear one-wheel steering drive wheel,
In front of the front drive wheels and in front of the rear drive wheels, caster driven wheels are provided on both sides of the drive wheels, and the drive wheels and the driven wheels are seesaw mounted on a wheel frame pivotally supported in the middle in the front-rear direction. An automatic guided vehicle, wherein the driven wheel side of a wheel frame is urged in a lifting direction in the automatic guided vehicle suspended in a shape. 2. A vehicle having one front and rear steering wheel.
In front of the front drive wheels and in front of the rear drive wheels, caster type driven wheels are provided on both sides of the drive wheels with the drive wheels interposed therebetween. An automatic guided vehicle suspended in an automatic guided vehicle, wherein a drive wheel side of a wheel frame is urged in a downward direction.