Automated Guided Vehicle

Abstract

To provide an unmanned carrier capable of stably conveying a cargo.SOLUTION: An unmanned carrier includes: axles in each of which both end parts have respective wheels; a frame supporting the axles swingingly; a lifting / lowering mechanism having lifting shafts installed on the axles, bearings provided on tips of the lifting shafts, and a top plate supported by the bearings; and a guide part provided on the frame and supporting the top plate to be lifted or lowered.SELECTED DRAWING: Figure 8

Description

Technical Field

[0001] The present disclosure relates to an automated guided vehicle.

Background Art

[0002] Conventionally, there is an automated guided vehicle in which a motor is attached to each of the wheels and each wheel is independently driven (for example, Patent Document 1). In the automated guided vehicle described in Patent Document 1, in order to improve the ground contact property of the wheels, a motor support member to which each motor is attached is swingably attached to the main body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, there is a demand for an automated guided vehicle that can stably transport a load, which is loaded with a load and can lift the loaded load.

Means for Solving the Problems

[0005] The present disclosure can be realized in the following forms. According to one aspect of the present disclosure, an automated guided vehicle is provided. The automated guided vehicle includes an axle with wheels attached to each of its two ends, and a wheel drive unit frame that rotatably supports the axle. The wheel drive unit frame rotatably supports a rotating shaft arranged along a second direction orthogonal to a first direction in which the axle extends. The automated guided vehicle also includes a lifting shaft erected on the axle, a bearing provided at the tip of the lifting shaft, a shaft portion arranged at the center of the bearing, and a top plate supported by the bearing. The top plate has a facing surface facing the wheel drive unit frame, and a lifting mechanism including these components. The automated guided vehicle further includes at least one top plate bar fixed to the facing surface so as to be perpendicular to the top plate, a wheel frame fixed to the rotating shaft, and at least one guide portion provided on the wheel frame. The at least one guide portion has a cylindrical shape and the lower end of the at least one top plate bar is inserted therethrough. The lifting shaft is a threaded shaft and is arranged along a third direction orthogonal to each of the first direction and the second direction. The lower end of the lifting shaft on the side opposite to the tip is rotatably supported by the wheel drive unit frame around the axis of the lifting shaft, and is arranged such that the axis of the lifting shaft passes through the axis of the rotating shaft. By rotating the lifting shaft around its axis, the bearing is configured to be movable up and down along the third direction. The shaft portion is arranged along the second direction, and the outer peripheral surface of the bearing is in contact with the facing surface.

[0006] According to one aspect of the present disclosure, an automated guided vehicle is provided. The automated guided vehicle includes an axle with wheels attached to each of its two ends, a frame that swingably supports the axle, a lifting shaft erected on the axle, a bearing provided at the tip of the lifting shaft, a top plate supported by the bearing, and a lifting mechanism having the above components. The automated guided vehicle further includes a guide portion provided on the frame that supports the top plate so as to be movable up and down. According to this aspect, when the axle swings, the vehicle can travel stably on a rough running surface. Even when the axle is inclined with respect to the horizontal direction, since the top plate is supported by the guide portion, the inclination of the top plate following the inclination of the axle can be suppressed. Therefore, the load placed on the top plate can be transported stably.

Brief Description of the Drawings

[0007]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0008] A. Embodiment: A1. Overall Configuration: FIG. 1 is a perspective view of the automated guided vehicle 1. FIG. 2 is a plan view of the automated guided vehicle 1. FIG. 3 is a side view of the automated guided vehicle 1. FIG. 4 is a perspective view of the wheel unit 20. FIG. 5 is a side view of the wheel unit 20. FIG. 6 is a front view of the wheel unit 20 shown together with the lifting mechanism 60. FIG. 7 is a sectional view taken along line VII-VII of FIG. 4. FIG. 8 is a sectional view taken along line VIII-VIII of FIG. 2. In FIGS. 1 to 8, the front-rear direction, the left-right direction, and the up-down direction that are orthogonal to each other are shown. The front direction is the forward direction of the automated guided vehicle 1. The automated guided vehicle 1 is a transport vehicle that can travel on the road surface by autonomous driving without the operation of a driver. Hereinafter, a case where the front-rear direction and the left-right direction are parallel to the horizontal direction and the up-down direction is parallel to the vertical direction will be exemplified and described. As shown in FIG. 1, the automated guided vehicle 1 includes a frame unit 10, two wheel units 20, two lifting mechanisms 60, and a power source 80.

[0009] The two wheel units 20 are arranged at intervals in the front and rear of the automated guided vehicle 1. As shown in FIG. 2, each wheel unit 20 includes a wheel drive unit frame 21 and two wheel drive units 30. As will be described in detail later, the wheel drive unit 30 includes a wheel shaft 31 extending in the left-right direction and a wheel 32 attached to an end of the wheel shaft 31. The two wheel shafts 31 included in the same wheel unit 20 are fixed to the wheel drive unit frame 21 so as to be located on the same axis.

[0010] The frame unit 10 shown in FIG. 1 includes two wheel frames 12 and a battery frame 14. The wheel frame 12 is configured by connecting prism members arranged on each side of a rectangular parallelepiped that generally surrounds the wheel unit 20. The battery frame 14 connects the two wheel frames 12. Specifically, the battery frame 14 is configured by a prism member that connects prism members extending in the left-right direction and arranged below each wheel frame 12.

[0011] A lifting mechanism 60 is disposed between two wheels 32 included in the same wheel unit 20. As shown in FIG. 3, each of the two lifting mechanisms 60 has a top plate 61 and is configured to be able to move the top plate 61 up and down independently of each other. As shown in FIGS. 1 and 3, the components of the lifting mechanism 60 described later are housed inside the cover 60a of the lifting mechanism 60. Further, FIG. 6 shows a state in which the top plate 61 is located at the lowermost position. On the other hand, FIGS. 7 and 8 show a state in which the top plate 61 is located upward.

[0012] As shown in FIG. 1, a power source 80 is disposed on the battery frame 14. The power source 80 is, for example, a battery and supplies power to the wheel unit 20 and the lifting mechanism 60. A control unit for controlling the operation of the automated guided vehicle 1 (not shown) is disposed above the power source 80.

[0013] The automated guided vehicle 1 transports the load W disposed on the lifting mechanism 60. After the load W is placed on the lifting mechanism 60 at the transport start point, the automated guided vehicle 1 travels to the destination. Then, when it arrives at the destination, with a load receiving arm (not shown) inserted under the load W, the lifting mechanism 60 descends, and the load W is transferred to the load receiving arm. FIG. 1 depicts one load W stacked across the two lifting mechanisms 60. The loading form of the load W is not limited to this. For example, there are forms in which separate loads W are loaded on each of the two lifting mechanisms 60, forms in which the load W is loaded only on one of the two lifting mechanisms 60, forms in which a plate is placed across the two lifting mechanisms 60 and the load W is loaded above the power source 80 on the plate, and the like. In this embodiment, the weight of the load W is about several tons.

[0014] A2. Configuration of the wheel unit: As shown in FIG. 2, in addition to the above configuration, the wheel drive unit 30 includes a motor 33, a speed reducer 34, a first pulley 35, a belt 36, a second pulley 37, an electromagnetic brake 38, and an encoder 39 for speed control. The motor 33, the speed reducer 34, the first pulley 35, the electromagnetic brake 38, and the encoder 39 are provided on the first central axis AX1. The rotational force of the motor 33 is reduced by the speed reducer 34 and output to an output shaft (not shown). A belt 36 is wound around the first pulley 35 provided integrally with the output shaft of the speed reducer 34 and the second pulley 37 provided integrally with the wheel shaft 31. Thereby, the rotational force of the motor 33 reduced by the speed reducer 34 is transmitted to the wheel shaft 31. In this way, by using the first pulley 35, the second pulley 37, and the belt 36, the motor 33 can be arranged at a position away from the second central axis AX2 which is the central axis of the wheel shaft 31. And an elevating mechanism 60 can be arranged between the two wheels 32.

[0015] The two wheel drive units 30 included in the same wheel unit 20 are arranged such that their respective first central axes AX1 face each other with the second central axis AX2 interposed therebetween. Also, as shown in FIG. 5, the first central axis AX1 which is the central axis of the motor 33 and the second central axis AX2 which is the central axis of the wheel are arranged at different positions in the vertical direction. As shown in FIG. 4, in this embodiment, the wheel 32 is realized by a mecanum wheel. Also, in this embodiment, the first pulley 35 and the belt 36 are housed in the case 41.

[0016] As shown in FIG. 4, the wheel drive unit frame 21 as a frame is generally a plate-shaped member parallel to the front-rear direction and the left-right direction. The wheel drive unit 30 is fixed to the wheel drive unit frame 21 via an L-shaped member. As shown in FIG. 8, the wheel shaft 31 is supported by a fixing member 21a fixed to the wheel drive unit frame 21 via a bearing mechanism 22. The bearing mechanism 22 has three bearings. The two wheel shafts 31 included in the same wheel unit 20 are fixed to the wheel drive unit frame 21 so as to be located on the second central axis AX2. That is, wheels 32 are attached to each of the two wheel shafts 31 as axle shafts and both end portions of the wheel drive unit frame 21. Thus, the axle shaft is not only a single shaft member but also a concept including a form in which a plurality of wheel shafts 31 are arranged on the same axis and connected to each other as in the present embodiment.

[0017] A3. Oscillation mechanism: In the present embodiment, among the two wheel units 20 shown in FIG. 1, the front wheel unit 20 oscillates about the third central axis AX3 of the automated guided vehicle 1 extending in the front-rear direction, and the rear wheel unit 20 is configured not to oscillate about the third central axis AX3. Thereby, even when there are irregularities on the traveling surface, at least three of the four wheels 32 can be in contact with the traveling surface, so that the traveling of the automated guided vehicle 1 can be stabilized. Note that both the front and rear wheel units 20 may be configured to be oscillatable with respect to the third central axis AX3.

[0018] As shown in FIG. 4, the wheel drive unit frame 21 is rotatably attached about the third central axis AX3. Specifically, as shown in FIG. 7, rotation shaft support members 25 are fixed to both front and rear ends of the wheel drive unit frame 21 in the front-rear direction. And each of the two rotation shafts 24 arranged along the third central axis AX3 is rotatably supported by the rotation shaft support member 25. Thereby, the wheel drive unit frame 21 can rotate about the rotation shaft 24. Thus, the wheel drive unit 30 attached to the wheel drive unit frame 21 can rotate about the rotation shaft 24 as the central axis.

[0019] A through hole extending in the front-rear direction for inserting the rotation shaft 24 is formed in the rotation shaft support member 25. A radial bearing 26a is disposed between the rotation shaft 24 and the inner peripheral surface of the through hole of the rotation shaft support member 25. The rotation shaft 24 has a head and a shaft portion extending from the head, and the outer peripheral surface of the tip of the shaft portion is screwed to the inner peripheral surfaces of the nuts 29a and 29b. In the direction of the third central axis AX3, the rotation shaft support member 25 is disposed between the nuts 29a and 29b and the head of the rotation shaft 24. A thrust bearing 26b is disposed between the nuts 29a and 29b and the opposing surfaces of the rotation shaft support member 25 with respect to the nuts 29a and 29b. A spacer 27 is disposed between the head of the rotation shaft 24 and the opposing surface of the rotation shaft support member 25 with respect to the head of the rotation shaft 24. In the direction of the third central axis AX3, a thrust bearing 26c is disposed between the spacer 27 and the end surface of the rotation shaft support member 25. Thereby, the wheel unit 20 can swing with respect to the third central axis AX3. As shown in FIG. 4, the swinging range of the wheel unit 20 is limited by a stopper 41 provided above the wheel 32.

[0020] A4. Lifting mechanism: As shown in FIG. 7, the elevating mechanism 60 is attached to the wheel drive unit frame 21. The elevating mechanism 60 raises and lowers the top plate 61 by means of a ball screw. The elevating mechanism 60 includes a top plate 61, an elevating motor 62, an elevating speed reducer 63, a bearing holder 64, a screw shaft 65 as an elevating shaft, an elevating nut 66, a housing 67, and a cam follower 68. The screw shaft 65 is erected on the axle. Specifically, the screw shaft 65 is arranged so that its axial direction coincides with that of a fourth central axis AX4 which passes through the second central axis AX2 and is parallel to the vertical direction. Thereby, the load of the load W loaded on the elevating mechanism 60 can be received by the axle, which is the wheel drive unit frame 21 in the present embodiment.

[0021] The lower end of the screw shaft 65 is rotatably supported by a bearing holder 64 attached to the wheel drive unit frame 21. An elevating nut 66 held by the housing 67 is attached to the upper part of the screw shaft 65. The housing 67 has a recess opening downward for receiving the screw shaft 65, and a cam follower 68 is attached to the upper tip. The cam follower 68 has a shaft portion 68a and two bearings 68b arranged at both ends of the shaft portion 68a. When the screw shaft 65 is in a posture along the vertical direction, the axial direction of the shaft portion 68a is attached in parallel with the front-rear direction. And the lower surface of the top plate 61 is supported by the bearing 68b of the cam follower 68. Thereby, as will be described in detail later, even when the front wheel unit 20 swings with respect to the third central axis AX3, the inclination of the top plate 61 with respect to the horizontal plane can be suppressed.

[0022] The screw shaft 65, the elevating nut 66, and balls (not shown) constitute a ball screw. The rotational force of the elevating motor 62 is decelerated by the elevating speed reducer 63 and then transmitted to the screw shaft 65. When the screw shaft 65 rotates in one direction, the elevating nut 66 rises, and when the screw shaft 65 rotates in the other direction, the elevating nut 66 descends. As the elevating nut 66 rises and falls, the top plate 61 supported by the cam follower 68 rises and falls.

[0023] A5. Support Structure of the Top Plate: The wheel frame 12 is fixed to the rotating shaft 24. Specifically, a first rotating shaft connecting portion 28a and a second rotating shaft connecting portion 28b are fixed to the rotating shaft 24. As shown in FIG. 6, the first rotating shaft connecting portion 28a is a circular flat plate member. The second rotating shaft connecting portion 28b is a rectangular flat plate member. The first rotating shaft connecting portion 28a and the second rotating shaft connecting portion 28b are formed with through holes penetrating in the thickness direction. As shown in FIG. 7, the rotating shaft 24 is inserted into the through hole of the first rotating shaft connecting portion 28a fitted into the second rotating shaft connecting portion 28b, and the first rotating shaft connecting portion 28a is fixed to the rotating shaft 24. And as shown in FIG. 6, the wheel frame 12 is fixed to the second rotating shaft connecting portion 28b via the frame-shaped frame 12a. Thus, in the present embodiment, the wheel drive unit frame 21 is swingably attached to the rotating shaft 24 to which the wheel frame 12 is fixed. Thereby, the axle is swingably supported by the frame unit 10 as a frame.

[0024] The top plate 61 is configured to move up and down parallel to the wheel frame 12. Four guide portions 16 are attached to the wheel frame 12. As shown in FIG. 6, two guide portions 16 are attached to both end portions in the left-right direction of the wheel frame 12. As shown in FIG. 7, two guide portions 16 are attached to both end portions in the front-rear direction of the wheel frame 12. As shown in FIG. 8, the guide portion 16 has a cylindrical shape, the axial direction is parallel to the vertical direction, and the upper end portion is fixed to the upper end of the wheel frame 12. Four top plate bars 61a are attached to the lower surface of the top plate 61 corresponding to the four guide portions 16. The top plate bar 61a is fixed substantially perpendicular to the top plate 61. The upper end of the top plate bar 61a is fixed to the lower surface of the top plate 61, and the lower end is inserted into the guide portion 16. Each top plate bar 61a fixed to the top plate 61 is guided by the guide portion 16 in the vertical movement. For this reason, the top plate 61 moves up and down parallel to the plane parallel to the front-rear direction and the left-right direction of the wheel frame 12.

[0025] As shown in FIG. 8, when the traveling surface is uneven, the wheel drive unit frame 21 swings around the third central axis AX3. Accordingly, the screw shaft 65 of the lifting mechanism 60 tilts in the vertical direction. Therefore, the contact point between the bearing 68b attached to the upper end of the screw shaft 65 and the lower surface of the top plate 61 moves on the track OB shown by the dashed line. The track OB is an arc centered on the third central axis AX3. Here, in this embodiment, even if the contact point between the bearing 68b and the lower surface of the top plate 61 deviates from the vertical line LV that passes through the third central axis AX3 and is parallel to the vertical direction, the tilt of the top plate 61 in the horizontal direction can be suppressed. This is because the top plate 61 moves parallel to the wheel frame 12 while being guided by the guide portion 16. Note that, when the contact point between the bearing 68b and the lower surface of the top plate 61 deviates from the vertical line LV, the top plate 61 moves downward as the bearing 68b moves downward.

[0026] Unlike this embodiment, in the case of a configuration in which the top plate 61 is fixed to the screw shaft 65, when the screw shaft 65 is tilted with respect to the vertical line LV, the top plate 61 also tilts with respect to the horizontal plane. In this regard, according to this embodiment, the top plate 61 is supported by the bearing 68b and is guided by the guide portion 16 to move up and down in parallel, so that the tilt of the top plate 61 with respect to the horizontal direction can be suppressed. This allows the luggage W to be transported stably.

[0027] Also, as described above, the screw shaft 65 is erected on the axle. As a result, the load of the load W can be received by the wheel drive unit frame 21 as an axle. When the screw shaft 65 is arranged at a position different from the second central axis AX2 which is the axle position in plan view, a connecting member for connecting the screw shaft 65 and the axle is required, and the connecting member needs to have rigidity enough to withstand the load. In this regard, in the present embodiment, since the load can be received by the axle, the unmanned carrier 1 for transporting the load W can be realized with a compact configuration. Further, since it is configured to swing the axle without using a suspension using an elastic body such as a spring, the position fluctuation of the top plate 61 in the vertical direction due to the load of the load W hardly occurs. Therefore, the transfer of the load W can be performed smoothly.

[0028] According to the embodiment described above, the unmanned carrier 1 includes the wheel shaft 31, the wheel drive unit frame 21, the wheel frame 12, the elevating mechanism 60, and the guide portion 16. Thereby, when the unmanned carrier 1 travels on a rough running surface, even when the wheel shaft 31 is inclined with respect to the horizontal direction, the top plate 61 is guided by the guide portion 16 to move in parallel with the wheel frame 12, so that the inclination of the top plate 61 following the inclination of the wheel shaft 31 can be suppressed.

[0029] B. Other Embodiments: (B1) In the above embodiment, the two wheel shafts 31 are connected by the wheel drive unit frame 21 to form an axle. As another form, wheels 32 may be attached to both ends of one axle.

[0030] The present disclosure is not limited to the above-described embodiments, and can be realized in various configurations without departing from the gist thereof. For example, the technical features of the embodiments corresponding to the technical features in each form described in the summary of the invention can be appropriately replaced or combined in order to solve some or all of the above-described problems or to achieve some or all of the above-described effects. Further, if the technical feature is not described as essential in this specification, it can be deleted as appropriate.

Description of Symbols

[0031] 1…Automated guided vehicle, 10…Frame unit, 12…Wheel frame, 12a…Frame-shaped frame, 14…Battery frame, 16…Guide part, 20…Wheel unit, 21…Wheel drive unit frame, 21a…Fixing member, 22…Bearing mechanism, 24…Rotating shaft, 25…Rotating shaft support member, 26a…Radial bearing, 26b, 26c…Thrust bearing, 27…Spacer, 28a…First rotating shaft connecting part, 28b…Second rotating shaft connecting part, 29a, 29b…Nuts, 30…Wheel drive unit, 31…Wheel shaft, 32…Wheel, 33…Motor, 34…Reducer, 35…First pulley, 36…Belt, 37…Second pulley, 38…Electromagnetic brake, 39…Encoder, 41…Stopper, 60…Lifting mechanism, 60a…Cover, 61…Top plate, 61a…Top plate bar, 62…Lifting motor, 63…Lifting reducer, 64…Bearing holder, 65…Screw shaft, 66…Lifting nut, 67…Housing, 68…Cam follower, 68a…Shaft part, 68b…Bearing, 80…Power supply, AX1…First central axis, AX2…Second central axis, AX3…Third central axis, AX4…Fourth central axis, LV…Vertical line, OB…Track, W…Load

Claims

【Claim 1】 An automated guided vehicle, comprising: an axle with wheels attached to each of its two ends; a wheel drive unit frame that rotatably supports the axle, the wheel drive unit frame rotatably supporting a rotating shaft arranged along a second direction orthogonal to a first direction in which the axle extends; a lifting shaft erected on the axle, a bearing provided at the tip of the lifting shaft, a shaft portion arranged at the center of the bearing, and a top plate supported by the bearing, the top plate having a facing surface facing the wheel drive unit frame; at least one top plate bar fixed to the facing surface so as to be perpendicular to the top plate; a wheel frame fixed to the rotating shaft; at least one guide portion provided on the wheel frame, the at least one guide portion having a cylindrical shape and through which the lower end of the at least one top plate bar is inserted; the lifting shaft is a threaded shaft, arranged along a third direction orthogonal to each of the first direction and the second direction, the lower end of the lifting shaft on the side opposite to the tip is rotatably supported by the wheel drive unit frame about the axis of the lifting shaft, and is arranged such that the axis of the lifting shaft passes through the axis of the rotating shaft, and by rotating the lifting shaft about the axis of the lifting shaft, the bearing is configured to be able to move up and down along the third direction; the shaft portion is arranged along the second direction, and the outer peripheral surface of the bearing is in contact with the facing surface. An automated guided vehicle.

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