JP2014186449A - Unmanned carrier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the rectilinear traveling performance and curve traveling performance of a vehicle while a driving wheel is disposed in only one part of a center part of a chassis in the longitudinal direction, in a low height type unmanned carrier allowing sneaking under the chassis.SOLUTION: The unmanned carrier sneaks under one bogie or a plurality of interconnected bogies having wheels and moves forward or backward of the bogie, and self-moves in an engaged state with an engaging object of the bogie, thereby automatically conveying the bogie. The unmanned carrier includes: a chassis; a pair of driving wheels 22 and 24 disposed in center part of the chassis in the longitudinal direction horizontally turnably in a predetermined angle range; a driven wheel attached to each of the front part and rear part of the chassis; and an elastic member 29 for elastically connecting the pair of driving wheels 22 and 24 to the chassis.

Description

  The present invention relates to an automated guided vehicle, and more particularly to an automated guided vehicle that automatically transports a wheeled carriage in a factory, a warehouse, a distribution center, or the like.

  2. Description of the Related Art Conventionally, in factories, warehouses, distribution centers, etc., labor saving is achieved by automatically transporting a wheeled carriage on which articles such as parts, products, and merchandise are loaded by an automatic guided vehicle. Such an automatic guided vehicle is also called AGV (Automatic Guided Vehicle).

  The automatic guided vehicle as described above generally includes a battery, a driving wheel driven by a motor by electric power supplied from the battery, and an induction line installed on a floor surface of a factory or the like, optically, magnetically, or A travel sensor that is detected by image processing or the like, and an engagement portion that engages with an engaged portion (for example, an engagement hole or an engagement recess) provided on the carriage. As a result, the automatic guided vehicle moves along the guide line by self-traveling while detecting the guide line by the travel sensor with the engaging portion engaged with the engaged portion of the cart. It can be pulled and conveyed.

  FIG. 8 shows an example in which the three wheeled carriages (indicated as “supply shelf” in the figure) 4 each carrying the article 2 are connected in series by the automatic guided vehicle 1. In this case, in order to be able to transport the three carriages 4 forward and backward, the automatic guided vehicle 1F coupled to the frontmost carriage 4 to pull the carriage 4 forward and the carriage 4 rearward The automatic guided vehicle 1 </ b> R connected to the last cart 4 is necessary for towing and transporting the vehicle.

  FIG. 9 shows an example in which a cart can be conveyed back and forth with one automatic guided vehicle 1A. This automatic guided vehicle 1A is provided with a front drive wheel 14F and a rear drive wheel 14R at the bottom of a chassis 12. The drive wheels 14F and 14R are respectively driven by motors 16F and 16R mounted at two locations on the front portion and the rear portion of the chassis 12. The front drive wheel 14F is driven when the automatic guided vehicle 1A travels forward, and conversely, the rear drive wheel 14R is driven when the automatic guided vehicle 1A travels backward. In addition, the automatic guided vehicle provided with the front drive wheel and the back drive wheel which are each driven by each motor in this way is described, for example in Unexamined-Japanese-Patent No. 10-268738 (patent document 1).

  Further, in the automatic guided vehicle 1 </ b> A shown in FIG. 9, an engagement device 18 is disposed at the center upper portion in the front-rear direction of the chassis 12. The engagement device 18 can cause the engagement cylinder 20 to protrude upward in response to a command from a control unit (not shown), whereby the engagement cylinder 20 is engaged with an engagement hole (a figure to be engaged) (see FIG. The automatic guided vehicle 1 </ b> A can be engaged with the carriage 4 by being inserted into the carriage 4.

  Here, it is preferable that the vertical height of the automatic guided vehicle 1 </ b> A is configured to be a low profile or a low vehicle height so as to be able to sink into a gap between the bottom plate of the wheeled carriage 4 and the traveling road surface. Thus, when pulling and conveying a plurality of carts 4 connected in series as shown in FIG. 8, each cart 4 is moved from a position where the cart 4 is engaged with the foremost cart 4 with the engagement cylinder 20 retracted. The rear drive wheel 14 </ b> R can be moved to a position where it can penetrate the bottom and engage with the last carriage 4, and the engagement cylinder 20 is protruded and engaged with the last carriage 4. By driving, each cart 4 can be pulled and conveyed rearward.

  Further, FIG. 10 shows an automatic guided vehicle 1B having a configuration similar to that of the automatic guided vehicle 1A shown in FIG. This automatic guided vehicle 1B has a driving wheel 14B at one central portion in the front-rear direction of the chassis 12, and has a free caster type driven wheel 15 that can turn in the horizontal direction and can rotate in contact with the traveling road surface. At the bottom of the four corners of the chassis 12.

  Specifically, the drive wheel 14B of the automatic guided vehicle 1B includes a pair of left and right motor-equipped drive wheels 22 and 24 as shown in the plan view of FIG. The left motorized drive wheel 22 includes a drive motor 26L and wheels 28L fixed to the motor shaft thereof, and the right motorized drive wheel 24 includes a drive motor 26R and wheels 28R fixed to the motor shaft thereof. Including. The pair of motor-equipped drive wheels 22 and 24 are integrally fixed to the chassis 12 adjacent to each other.

  As described above, in the automatic guided vehicle 1B, the driving wheel 14B is provided in one place in the center portion in the front-rear direction of the chassis 12, and the driving wheel 14B is properly connected with the engagement cylinder 20 of the engagement device 18 engaged with the carriage 4. By rotating or reversing, the automatic guided vehicle 1B can be driven back and forth, and the cart 4 can be pulled and conveyed in the front-rear direction.

Japanese Patent Laid-Open No. 10-268738

  In the example described with reference to FIG. 8, two automatic guided vehicles 1 </ b> F and 1 </ b> R are required to pull and convey a plurality of carts 4 connected in series in the front-rear direction, which increases the cost of equipment installation. There is.

  Further, in the example described with reference to FIG. 9, the cart 4 can be conveyed in the front-rear direction by one automatic guided vehicle 1 </ b> A. However, it is necessary to provide drive motors at two locations on the front and rear of the vehicle platform 12. The problem of high manufacturing costs arises.

  On the other hand, in the automatic guided vehicle 1B described with reference to FIG. 10, the drive wheel 14B is provided at only one place in the center in the front-rear direction of the chassis 12, and the drive wheel 14B is attached and the electrical wiring is routed. There is an advantage that the manufacturing cost can be reduced because the number of drive motors is reduced while the work becomes easy.

  However, in the automatic guided vehicle 1B, since the driving wheel 14B is installed in the center part in the front-rear direction of the chassis 12, the traveling direction of the automatic guided vehicle 1B, in particular, traveling performance at the time of curve traveling tends to become unstable, There is a risk that the traction force is reduced.

  One object of the present invention is to improve the running performance of an automated guided vehicle while installing a drive wheel at only one central portion in the front-rear direction of the chassis in a low vehicle height automated guided vehicle that can pass under the chassis. It is to let you. Another object of the present invention is to increase the traction force of the automatic guided vehicle.

  The automatic guided vehicle according to the present invention passes under one carriage with wheels or a plurality of carriages connected to each other, moves forward or backward of the carriage, and engages with an engaged portion of the carriage. An automated guided vehicle that automatically conveys the carriage by self-propelled in a state where the carriage, a pair of drive wheels that are horizontally turnable at the center in the front-rear direction of the carriage, and a front of the carriage Driven wheels respectively attached to the rear portion and the rear portion, and an elastic member that elastically connects the pair of drive wheels to the chassis.

  In the automatic guided vehicle according to the present invention, a plurality of the elastic members are provided, and the elastic member on the left side and the elastic member on the right side are equally elastically distributed with respect to the drive wheel when the automatic guided vehicle travels straight. You may be comprised so that.

  Moreover, the automatic guided vehicle according to the present invention may be configured such that the center of gravity is located at a center portion in the front-rear direction of the chassis.

  According to the automatic guided vehicle of the present invention, the pair of drive wheels that are turnably provided at the center in the front-rear direction of the chassis are elastically connected to the chassis via the elastic member. Even if the pair of drive wheels are shaken due to the speed difference, it is possible to suppress the shake being absorbed by the elastic member and transmitted to the chassis. As a result, the running stability of the automated guided vehicle can be prevented from being hindered by reaction force from the cart caused by the shake of the chassis of the automated guided vehicle that engages with the cart and travels straight. Performance is improved.

  In addition, if a plurality of elastic members are provided and the left and right elastic members are equally elastically distributed with respect to the drive wheels when the automatic guided vehicle travels straight, a pair of the elastic members is provided. When the drive wheel turns, an elastic force acts so as to immediately correct its direction, and as a result, the straight traveling performance of the automatic guided vehicle is improved.

  Furthermore, if the center of gravity is configured to be located at the center in the front-rear direction center of the chassis, the pair of drive wheels can be pressed against the road surface, and as a result, the slip of the drive wheels is suppressed and the traction force is increased. Can be increased.

It is a perspective view which shows the automatic guided vehicle which is embodiment of this invention. It is the top view which looked at a pair of drive wheels from the upper part. It is the sectional view on the AA line in FIG. It is a block diagram which shows the electric system of the automatic guided vehicle of this embodiment. It is a figure which shows a mode that the automatic guided vehicle shown in FIG. 1 penetrates under the several trolley | bogie connected in series. It is a time chart which shows the detection signal of the travel sensor at the time of straight traveling, and the rotational speed of a driving wheel. It is a time chart which shows the detection signal of the driving | running | working sensor at the time of left curve driving | running | working, and the rotational speed of a driving wheel. It is a figure which shows an example of the conventional automatic guided vehicle. It is a figure which shows another example of the conventional automatic guided vehicle. It is a figure which shows another example of the conventional automatic guided vehicle.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention (hereinafter referred to as embodiments) will be described in detail with reference to the accompanying drawings. In this description, specific shapes, materials, numerical values, directions, and the like are examples for facilitating the understanding of the present invention, and can be appropriately changed according to the application, purpose, specification, and the like. In addition, when a plurality of embodiments and modifications are included in the following, it is assumed from the beginning that these characteristic portions are used in appropriate combinations.

  In the following description, the same or similar reference numerals are used for the components corresponding to the automatic guided vehicle described with reference to FIGS.

  FIG. 1 is a perspective view showing an automatic guided vehicle 10 according to the present embodiment. In FIG. 1, the height direction is indicated by an arrow H, the length direction is indicated by an arrow L, and the width direction is indicated by an arrow W. The automatic guided vehicle 10 passes under one carriage 4 with wheels or a plurality of series-connected carriages 4 and moves to the front or rear of the carriage 4 to be engaged with an engaged portion of the carriage 4. It is an automatic guided conveyance vehicle that automatically conveys the carriage 4 by self-propelling along the guidance line in the combined state.

  As shown in FIG. 1, the automatic guided vehicle 10 includes a chassis 12, a drive wheel 14, a driven wheel 15, a battery 30, and a control unit 40.

  The chassis 12 is constituted by a frame extending in the front-rear direction. The chassis 12 includes a front frame portion 12A, a rear frame portion 12B, and an intermediate frame portion 12C that connects them. Each frame part 12A, 12B, 12C is formed by, for example, fixing a metal long member having an L-shaped cross section by a method such as welding or screwing.

  Each of the front frame portion 12A and the rear frame portion 12B is configured as a frame body in which a long metal member is disposed in a portion corresponding to a side portion of a rectangular parallelepiped. The front frame portion 12A and the rear frame portion 12B are connected by a plurality (two in the present embodiment) of intermediate frame portions 12C. The intermediate frame portion 12C is preferably arranged so as to be flush with the upper surfaces of the frame portions 12A and 12B.

  A total of four driven wheels 15 are attached to the lower portions of the front frame 12A and the rear frame portion 12B. Although only two driven wheels 15 are shown in FIG. 1, the remaining two driven wheels 15 are arranged on the opposite side of the chassis 12 in the width direction. The driven wheel 15 is preferably a free caster type wheel that can turn and can be driven and rotated in contact with the road surface, but is not limited to this, and may be a caster that does not turn.

  A front top plate 51F is attached to the upper portion of the front frame portion 12A of the chassis 12. A start / stop switch 52, a display unit 53, and a speaker 54 are attached to the front top plate 51F. The start / stop switch 52 is an operation switch for starting or stopping the automatic guided vehicle 10 when the operator pushes it. The display part 53 is comprised, for example with a liquid crystal display etc., and has the function to display the information (for example, the remaining capacity of the battery 30, etc.) regarding the automatic guided vehicle 10. In addition, the speaker 54 is for making a sound indicating that the automatic guided vehicle 10 is running to alert the surrounding workers.

  A bottom plate 55 is fixed to the lower portion of the front frame portion 12 </ b> A of the chassis 12. A control unit 40 is fixed on the bottom plate 55. The control unit 40 includes an electric circuit that controls the operation of the automatic guided vehicle 10. The control unit 40 may include a microcomputer including a central processing unit (CPU) and a storage device (ROM, RAM, etc.), for example.

  The front top plate 51F of the front frame portion 12A may be hingedly connected to the front frame portion 12A so as to be opened and closed. By doing so, there is an advantage that the front top plate 51F is opened, and the access to the control unit 40 and the like disposed on the back surface or the lower side and the work are facilitated. The same applies to the rear top plate described below.

  A rear top plate 51B is attached to the upper portion of the rear frame portion 12B of the chassis 12. A start stop switch 52 is also provided on the rear top plate 51B.

  A metal front support plate 32F made of, for example, aluminum is mounted on the intermediate frame portion 12C adjacent to the front frame portion 12A of the chassis 12. The front support plate 32F is disposed along the width direction of the chassis 12 and is spanned between the two intermediate frame portions 12C. A front cylinder lifting device 20F is provided at the center in the width direction of the front support plate 32F. The front cylinder elevating device 20F is preferably configured by, for example, an electromagnetic solenoid.

  Similarly, a rear support plate 32B made of a metal such as aluminum is mounted on the intermediate frame portion 12C adjacent to the rear frame portion 12B of the chassis 12. The rear support plate 32B is disposed along the width direction of the chassis 12 and is spanned between the two intermediate frame portions 12C. A rear cylinder lifting device 20B is provided at the center position in the width direction of the rear support plate 32B. The rear cylinder elevating device 20B is also preferably configured by, for example, an electromagnetic solenoid.

  A central support plate 32 is attached on the intermediate frame 12 </ b> C at the center in the length direction of the chassis 12. The central support plate 32C is made of a plate material made of metal such as aluminum, for example. The central support plate 32C is disposed along the width direction of the chassis 12 and is installed between the two intermediate frame portions 12C. A bearing member 56 such as a bearing is fixed at the center position in the width direction of the center support plate 32C.

  FIG. 2 is a plan view of a pair of drive wheels as viewed from above. 3 is a cross-sectional view taken along line AA in FIG. As shown in FIGS. 1 to 3, the automatic guided vehicle 10 includes a drive wheel 14 at a central position in the length direction. The drive wheel 14 includes a pair of left and right motor-equipped drive wheels 22 and 24. In the following, the motor-equipped drive wheel 22 disposed on the left side (upper side of the paper surface) facing forward (right side of the paper surface) in FIG. 1 is referred to as the left drive wheel, and is disposed on the right side (lower side of the paper surface). The motor-equipped drive wheel 24 is referred to as a right drive wheel.

  The left drive wheel 22 includes a left drive motor 26L and a left drive wheel 28L fixed to the motor shaft thereof. Similarly, the right drive wheel 24 includes a right drive motor 26R and a right drive wheel 28R fixed to the motor shaft. The drive motors 26L and 26R are integrally formed and installed so that the rotation center axes of the left and right drive wheels 28L and 28R are aligned in a straight line. Further, the left and right drive wheels 28L and 28R are arranged at positions that fit inside the width direction of the chassis 12. Further, each of the drive motors 26L and 26R is configured to be able to control the rotation speed independently in response to a command from the control unit 40.

  A pair of travel sensors 62L and 62R are attached to the drive motors 26L and 26R of the pair of left and right drive wheels 22 and 24 via a sensor bracket 60. The left travel sensor 62L and the right travel sensor 62R are provided at a predetermined interval s. Each traveling sensor 62L, 62R is preferably configured by an optical sensor including a light emitting element and a light receiving element, for example. As will be described later, the automatic guided vehicle 10 travels while detecting one edge portion of the guide line G installed on the traveling road surface by the traveling sensors 62L and 62R.

  In this embodiment, optical sensors including light emitting / receiving elements are used for the travel sensors 62L and 62R, but the present invention is not limited to this. For example, when a magnetic tape is used for the guide line G, a magnetic detection sensor may be used. Alternatively, it may be possible to use a camera or the like instead of the sensor to photograph the guide line and analyze the image to detect the guide line while traveling.

  As shown in FIG. 2, the pair of drive wheels 22 is elastically connected to the chassis 12 by an elastic member 29. Specifically, in this embodiment, a plurality of coil springs are used as the elastic member 29, and one end of each coil spring 29 is locked to the left and right drive motors 26L, 26R. Each coil spring 29 is provided so as to apply a horizontal pulling force to the pair of drive motors 26L, 26R.

  More specifically, the hooks at one end portions of the two coil springs 29 are hooked on the side surface of the left drive motor 26L, and the hooks at the other end portions constitute a part of the intermediate frame portion 12C of the chassis 12. Locked to the portion 13. Further, the hooks at one end portions of the remaining two coil springs 29 are respectively hooked on the side surfaces of the right drive motor 26R, and the hooks at the other end portions constitute a part of the intermediate frame portion 12C of the chassis 12. Locked to the frame portion 13. Thereby, when the automatic guided vehicle 10 travels straight, elastic force (tensile force in this embodiment) is equally distributed between the two left coil springs 29 and the two right coil springs 29 with respect to the drive wheel 14. It is comprised so that. For this reason, when the pair of drive wheels 22 and 24 turn, a tensile force acts so as to immediately correct the direction, and as a result, the straight traveling performance of the automatic guided vehicle 10 is improved.

  Although the illustration of the locking frame portion 13 is omitted in FIG. 1, the upper end portion is fixed to the intermediate frame portion 12C by a method such as welding or screwing, and is made of a metal plate material that hangs downward therefrom. Is formed. In the present embodiment, an example in which the four coil springs 29 are arranged along the width direction of the chassis 12 is shown. However, the present invention is not limited to this. ) May be stretched and arranged. Furthermore, the number of coil springs 29 is not limited to four, and may be at least two.

  The pair of drive wheels 22 and 24 are provided at the central portion in the front-rear direction of the chassis 12 so as to be horizontally turnable. Specifically, as shown in FIG. 3, a support shaft 27 is fixed to the upper part of the left and right drive motors 26L, 26R so as to extend vertically upward. The support shaft 27 passes through the bearing member 56 fixed to the center support plate 32C of the chassis 12 and is supported by the top and bottom by a retaining member 34 such as a C-shaped ring so as to be rotatable. .

  As a result, the pair of drive wheels 22 and 24 are supported so as to be able to turn in the horizontal direction, and as described above, the pulling force is uniformly applied to the outer periphery by the four coil springs 29, whereby the left and right drive wheels 28L. , 28R are held in the front-rear direction.

  As shown in FIG. 3, two batteries 30 are provided with a pair of drive wheels 22 and 24 sandwiched between both sides in the front-rear direction. Thereby, it is comprised so that a gravity center may be located in the center part (namely, part in which the driving wheel 14 is provided) of the front-back direction of the chassis 12. As the battery 30, a chargeable / dischargeable secondary battery is used. As the battery 30, for example, a vehicle-mounted 12V lead battery can be suitably used. By using such a counter article, the manufacturing cost of the automatic guided vehicle 10 can be suppressed. However, it is not limited to this, For example, secondary batteries, such as a lithium ion battery and a nickel metal hydride battery, may be used.

  The two batteries 30 are supported by a bracket 31 fixed to the central support plate 32C of the chassis 12 by screwing or the like. The bracket 31 includes an upper portion 31a fixed to the central support plate 32C, a side wall portion 31b that hangs down from an end portion in the front-rear direction of the upper portion 31a, and a tray portion 31c that extends in the horizontal direction at the lower end portion of the side wall portion 31b. Have Each battery 30 is placed on a tray portion 31 c of the bracket 31. As a result, the weights of the two batteries 30 act so as to press the pair of drive wheels 22 and 24 downward via the bracket 31 and the central support plate 32C, and as a result, the left and right drive wheels 28L and 28R with respect to the traveling road surface. This increases the gripping force and makes it difficult to slip, and the traction force of the automatic guided vehicle 10 can be increased.

  In the above description, an example in which a coil spring is used as an elastic member for applying an elastic force to the pair of drive wheels 22 and 24 has been described. However, instead of or in addition to this, a compression spring, a torsion spring, or the like is used. The pair of drive motors 26L and 26R may be elastically connected to the chassis 12 using an elastic member.

  FIG. 4 is a block diagram showing an electrical system of the automatic guided vehicle of the present embodiment. As shown in FIG. 4, a battery 30 is connected to the control unit 40 so that electric power necessary for the operation of the automatic guided vehicle 10 is supplied. Further, the control unit 40 includes a left travel sensor 62L, a right travel sensor 62R, a front / rear start / stop switch (indicated as “start switch” in the figure) 52, a left drive motor 26L, a right drive motor 26R, front and rear cylinders. Elevator 18F, 18B, the display part 53, and the speaker 54 are connected.

  The left drive motor 26L is a motor that rotationally drives the left drive wheel 28L, and the start and stop of rotation, the rotation speed, and the rotation direction can be controlled independently of the right drive motor 26R in accordance with commands from the control unit 40. It has become. The right drive motor 26R is a motor that rotationally drives the right drive wheel 28R, and in accordance with commands from the control unit 40, the start and stop of rotation, the rotation speed, and the rotation direction are independent from the left drive motor 26L. Can be controlled.

  As described above, the front and rear cylinder lifting devices 18F and 18B project the engagement cylinder 20 from the upper surface of the chassis 12, and the engaged parts 6 of the carriage 4 (see FIG. 5) that is the object to be conveyed. By engaging with 8, the cart 4 can be pulled and conveyed as the automatic guided vehicle 10 travels. Although not shown, sensors or cameras for checking the positions of the engaged portions 6 and 8 of the carriage 4 are provided in the vicinity of the front and rear cylinder lifting devices 18F and 18B. Based on information from this sensor or the like, the cylinder elevating device 18 can be operated to project the engagement cylinder 20 at a timing when the engagement cylinder 20 is aligned with the engaged portions 6 and 8 of the carriage 4. In order to ensure the engagement of the engagement cylinder 20 with the engaged portions 6 and 8, a guide member may be provided on the cart 4 side.

  The communication unit 42 transmits and receives information necessary for traveling of the automatic guided vehicle 10 by transmitting and receiving information to and from a control device (not shown) fixedly installed in a factory or the like where the automatic guided vehicle 10 is used. Is for. For example, this information may include, for example, information that allows an operator to complete the loading of an article on a carriage and permits the automatic guided vehicle 10 to start, information that changes a traveling method at a branch point of the guide line, and the like.

  Next, the operation of the automatic guided vehicle 10 having the above configuration will be described with reference to FIG. FIG. 5 is a diagram illustrating a state in which the automatic guided vehicle 10 illustrated in FIG. 1 passes under a plurality of carts connected in series.

  In the automatic guided vehicle 10 of the present embodiment, the height of the chassis 12 including the driven wheels 15 is configured so as to be low so that the height of the chassis 12 can pass under the carriage 4. By driving the pair of drive wheels 22 and 24 provided only at one central portion in the direction to rotate forward or reverse, the vehicle can travel in either the front or rear direction.

  Therefore, as shown in FIG. 5, for example, when the three wheeled carriages 4 that are supply shelves are transported forward in a state of being connected in series, the rear part is engaged with the engaged part 6 of the carriage 4 located in the foremost part. With the engagement cylinder 20 of the cylinder lifting and lowering device 18B engaged, the drive wheel 14 can be driven forward so that it can be pulled and conveyed in the direction of arrow C.

  On the contrary, when these carts 4 are transported rearward, the automatic guided vehicle 10 passes through the bottom of each cart 4 with the engagement cylinder 20 of the rear cylinder lifting device 18B retracted, and is positioned at the end. The undercarriage 4 is moved below, and the engagement cylinder 20 of the front cylinder lifting device 18F is protruded to engage with the engaged portion 8 of the carriage 4, and the drive wheel 14 is driven in reverse in this state. Thus, the carriage 4 can be pulled and conveyed in the direction of arrow D.

  Therefore, according to the automatic guided vehicle 10 of the present embodiment, a plurality of carts 4 connected in series can be pulled and transported in either the front or back direction by one unit, and at that time, the vehicle 4 dives under the cart 4. Since it can move out, it can be quickly engaged or connected to the front or rear of the carriage 4. The same applies to the case where one carriage 4 is pulled (or pushed) and conveyed.

  Further, the automatic guided vehicle 10 of the present embodiment includes front and rear cylinder lifting devices 18F and 18B, and operates the cylinder lifting device positioned behind the driving wheel 14 in the pulling direction to operate the cart 4. In particular, the traction can be performed stably when transporting a cart having a large load weight or a plurality of carts connected in series.

  FIG. 6 is a time chart showing the detection signal of the travel sensor and the rotational speed of the drive wheel during straight traveling. (A) shows the signal state of the left travel sensor 62L, (b) shows the signal state of the right travel sensor 62R, (c) shows the rotational speed of the left drive motor 26L, and (d) shows the right drive motor 26R. The horizontal axis represents the common time axis (a) to (d).

  Referring to FIG. 6, when the automated guided vehicle 10 travels straight along a guide line G (see FIG. 2) linearly installed on the traveling road surface, the left-side travel sensor 62 </ b> L detects the edge of the guide line G. When turned on, the left drive motor 26L decelerates while the right drive motor 26R accelerates at the times t1, t3, t5, t7, and t9. On the other hand, when the right traveling sensor 62R is off from the edge of the guide line G and cannot be detected, the left driving motor 26L accelerates at the timings t2, t4, t6, t8, and t10, while the right driving motor 26R. Will slow down.

  In this way, the left and right drive motors 26L and 26R alternately accelerate and decelerate, so that the pair of drive wheels 22 and 24 provided so as to be able to turn with respect to the chassis 12 rotate in small increments. In the present embodiment, such a rotation operation is absorbed by the expansion and contraction of the coil spring 29, so that no vibration is transmitted to the chassis 12. Therefore, according to the automatic guided vehicle 10 of the present embodiment, it is possible to travel straight in a stable state without shaking the chassis 12.

  FIG. 7 is a time chart showing the detection signal of the travel sensor and the rotational speed of the drive wheel during left curve travel. (A)-(d) in FIG. 7 is the same as that of FIG.

  Referring to FIG. 7, acceleration and deceleration are alternately repeated according to the signal states of the left and right traveling sensors 62L and 62R, as in the case of straight traveling. However, when traveling on the left curve, the on period of the left traveling sensor 62 is shortened while the off period of the right traveling sensor 62R is elongated compared to when traveling straight. Thereby, in the control unit 40, it can be judged that the automatic guided vehicle 10 is approaching the left curve. At this time, for example, by making the acceleration / deceleration amount of the left drive motor 26L smaller than the right drive motor 26R (or making the acceleration / deceleration amount of the right drive motor 26R larger than the left drive motor 26L), the automatic guided vehicle 10 Can be driven along the guidance line G to the left. Note that, when running on the right curve, the control opposite to that described above is performed.

  As described above, even when the automatic guided vehicle 10 travels in a curve, the pair of drive wheels 22 and 24 provided so as to be turnable with respect to the chassis 12 rotate in small increments. Since the turning operation is absorbed by the expansion and contraction of the coil spring 29, vibration is not transmitted to the chassis 12.

  Usually, when the automated guided vehicle travels in a curve, a phenomenon has been observed in which the chassis 12 derails without being completely bent by the reaction force received from the engaged portions 6 and 8 of the carriage 4 by the engagement cylinder 20. Such a phenomenon was observed particularly when the weight of the carriage was large or when the curvature radius of the curve was small. On the other hand, in the automatic guided vehicle 10 of the present embodiment, the reaction force as described above is also absorbed by the expansion and contraction of the coil spring 29, so that the pair of drive wheels 22 and 24 are warped from the curved guide line G. The reaction force can be prevented or reduced. Therefore, according to the automatic guided vehicle 10 of the present embodiment, the vehicle can reliably travel along the curved guide line G.

  The automatic guided vehicle according to the present invention is not limited to the configuration of the above-described embodiment, and various improvements and modifications can be made within the scope of the matters described in the claims of the present application and equivalents thereof. Is possible.

  2 article, 4 cart, 6,8 engaged portion, 10 automatic guided vehicle, 12 chassis, 12A front frame portion, 12B rear frame portion, 12C intermediate frame portion, 13 locking frame portion, 14 drive wheel, 15 follower Driving wheel, 18B Rear cylinder lifting device, 18F Front cylinder lifting device, 20 Engaging cylinder, 22 Left drive wheel, 24 Right drive wheel, 26L Left drive motor, 26R Right drive motor, 27 Support shaft, 28L Left drive wheel, 28R Right drive wheel, 29 elastic member or coil spring, 30 battery, 31 bracket, 31a upper part, 31b side wall part, 31c saucer part, 32B rear support plate, 32C center support plate, 32F front support plate, 34 retaining member, 40 control Unit, 51B Rear top plate, 51F Front top plate, 52 Start stop switch, 53 tables Parts, 54 speaker, 55 bottom plate, 56 a bearing member, 60 sensor bracket, 62L left traveling sensor, 62R right travel sensor, G induction line.

Claims (3)

By passing under one carriage with wheels or a plurality of carriages connected to each other, moving forward or rearward of the carriage, and self-running in a state of being engaged with an engaged portion of the carriage An automated guided vehicle that automatically transports a carriage,
The chassis,
A pair of drive wheels provided at the center in the front-rear direction of the chassis so as to be horizontally turnable;
Driven wheels respectively attached to the front and rear of the chassis;
An elastic member for elastically connecting the pair of drive wheels to the chassis;
Automated guided vehicle equipped with. In the automatic guided vehicle according to claim 1,
A plurality of the elastic members are provided, and are arranged so as to be elastically distributed evenly between the elastic member on the left side and the elastic member on the right side with respect to the drive wheel when the automatic guided vehicle travels straight. An automated guided vehicle. In the automatic guided vehicle according to claim 1 or 2,
The automatic guided vehicle is configured such that a center of gravity is positioned at a center portion in a front-rear direction of the chassis.

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