Anti-tip mechanism and automated guided vehicle

Abstract

To suppress a wheel load of a driving wheel within a limit of a floor load during traveling, and to prevent fall during cargo handling.SOLUTION: A fall prevention mechanism 2 includes an upper link 20a, a horizontal plate 21a, a spring 23a, and an actuator 27. In the upper link 20a, a first end part is connected to a vehicle body frame 10a so as to swing vertically via a first rotary shaft 28a, and a second end part is connected to a driving wheel 12. The horizontal plate 21a is constituted so as to swing with the first rotary shaft 28a as a fulcrum. An adjustment spring 23 energizes the horizontal plate 21a upward, swings front and back links 20 downward and presses the driving wheel 12 down to the ground. The actuator 27 is constituted so as to press the horizontal plate 21a downward, and at the time of cargo handling, presses the horizontal plate 21a downward, and reduces a pressing force with respect to the driving wheel 12.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a tip-over prevention mechanism for an unmanned guided vehicle and an unmanned guided vehicle equipped with said tip-over prevention mechanism. [Background technology]

[0002] Conventionally, as an example of an automated guided vehicle that autonomously performs loading and unloading work, there is an automated guided vehicle disclosed in Patent Document 1. This automated guided vehicle has a vehicle body, wheels, and a loading unit (loading device). The loading unit has a mast and forks, and is configured to scoop up a load with the forks. The mast is configured to be movable in the front-rear direction via a connection part, and four wheels are provided on the connection part (see FIG. 4 of Patent Document 1). This automated guided vehicle is configured to adjust the load applied to the wheels to be steered by adjusting the position of the loading unit so that the steering angle can be smoothly adjusted when the vehicle body is stopped.

[0003] Incidentally, in facilities with floor load restrictions, it is necessary to adjust the load on the wheels even when the vehicle is moving, but the automated guided vehicle disclosed in Patent Document 1 only aims to adjust the load on the wheels when the vehicle is stopped. Also, when the forks are moved forward during loading and unloading, the automated guided vehicle disclosed in Patent Document 1 may tip over toward the forks if the load scooped up by the forks is heavier than expected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2020-200154 A Summary of the Invention [Problem to be solved by the invention]

[0005] Therefore, the problem that the present invention aims to solve is to provide an anti-tip mechanism for an unmanned guided vehicle that can suppress the wheel load of the drive wheels during driving within the floor load limit and prevent tipping during loading and unloading, and an unmanned guided vehicle equipped with said anti-tip mechanism. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems, the present invention provides a tip-over prevention mechanism that is provided on an unmanned guided vehicle, the unmanned guided vehicle comprising a vehicle body having left and right vehicle body frames extending vertically, driven wheels arranged on the front, rear, left and right of the vehicle body, left and right drive wheels arranged respectively between the front and rear driven wheels, and a loading device configured to be movable in the front-rear direction, the tip-over prevention mechanism being provided on the left and right sides of the unmanned guided vehicle, and comprising front and rear links each having a first end connected to the vehicle body frame via a rotating shaft so as to be swingable up and down and a second end connected to the drive wheel, a horizontal section having a horizontal plate extending from the rotating shaft in the opposite direction to the drive wheel and configured to be swingable about the rotating shaft, an adjustment spring configured to urge the horizontal plate upward and swing the front and rear links downward to press the drive wheel against the ground, and an actuator fixed to the vehicle body frame and configured to press the horizontal plate downward, the actuator being configured to press the horizontal plate downward during loading and unloading to reduce the pressing force on the drive wheel.

[0007] The anti-tip mechanism is preferably configured such that, when the automated guided vehicle handles cargo, the actuator pushes the horizontal plate downward to completely lift the drive wheels off the ground.

[0008] The tip-over prevention mechanism is preferably configured so that the actuator does not press down on the horizontal plate when the automatic guided vehicle is traveling.

[0009] The tip-over prevention mechanism preferably further includes left and right jack arms. Each jack arm has a jack body and a jack arm, is configured to be able to press the jack arm against the ground, is disposed forward of the driven wheels, is separated from the ground when the automated guided vehicle is traveling, and is configured to press the ground when the automated guided vehicle is loading and unloading.

[0010] In the above-mentioned tip-over prevention mechanism, the actuator is preferably configured by a hydraulic cylinder.

[0011] The above-mentioned anti-tip mechanism preferably has an actuator having a shaft extending horizontally, and the anti-tip mechanism further includes a guide fixed to the horizontal plate for guiding the shaft in the vertical direction, and the actuator is configured to push the horizontal plate downward by lowering the shaft.

[0012] In the above-mentioned anti-tip mechanism, the automated guided vehicle preferably further includes a drive unit, the front and rear links are connected to the drive wheels via the drive unit, and the drive unit is configured to be raised and lowered together with the drive wheels.

[0013] In the above-mentioned anti-toppling mechanism, the drive unit preferably has a drive unit frame, a drive motor, a brake, a steering motor, and a swivel bearing, and the front and rear links are connected to the drive wheels via the drive unit frame.

[0014] The anti-tip mechanism has, for example, a loading device having a mast and forks.

[0015] In order to solve the above problem, the automated guided vehicle according to the present invention is characterized in that it is equipped with the above-mentioned anti-toppling mechanism. Effect of the Invention

[0016] The tip-over prevention mechanism and automated guided vehicle according to the present invention can suppress the wheel load of the drive wheels during travel within the floor load limit, and can prevent tip-over during loading and unloading. [Brief description of the drawings]

[0017] [Figure 1] 1 is a schematic plan view of an automated guided vehicle according to one embodiment of the present invention, in which A shows the forks stored in the vehicle body, and B shows the forks moved to the front of the vehicle body. [Diagram 2] 2 is a schematic side view showing a drive unit and a part of a tip-over prevention mechanism. FIG. [Diagram 3] FIG. 2 is a functional block diagram of an automated guided vehicle. [Figure 4] FIG. 1B is a schematic plan view showing a part of the tip-over prevention mechanism on the right side of FIG. 1A. [Diagram 5] 1A is a schematic front view showing a part of the anti-toppling mechanism, where FIG. 1B shows the state during loading and unloading. [Figure 6] FIG. 4 is a perspective view showing a part of the anti-tip mechanism. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Hereinafter, an embodiment of the tip-over prevention mechanism and the automated guided vehicle of the present invention will be described with reference to the attached drawings. In the present invention, the front-rear direction is based on the moving direction of the loading device, and the arrow X in the drawing indicates the left-right direction, the arrow Y indicates the front-rear direction, and the arrow Z indicates the up-down direction.

[0019] <Automated Guided Vehicle> First, the configuration of the automated guided vehicle 1 will be described. Fig. 1 is a plan view of the automated guided vehicle 1 according to this embodiment. The automated guided vehicle 1 according to this embodiment is a side-fork vehicle, but the automated guided vehicle 1 according to the present invention is not limited to a side-fork vehicle. For example, the automated guided vehicle 1 may be a 3-way forklift that can handle cargo in three directions, forward, left, and right, without changing the orientation of the vehicle body 10.

[0020] As shown in FIG. 1A, the automated guided vehicle 1 includes a vehicle body 10, four driven wheels 14, left and right drive wheels 12, left and right drive units 15, a loading device 16, and left and right anti-toppling mechanisms 2.

[0021] The vehicle body 10 has left and right vehicle body frames 10a extending vertically. Four driven wheels 14 are disposed on the front, rear, left and right sides of the vehicle body 10. The left and right drive wheels 12 are disposed between the front and rear driven wheels 14, respectively.

[0022] Fig. 2 is a side view showing a part of the drive unit 15 and the tip-over prevention mechanism 2. As shown in Fig. 2, the drive unit 15 has a drive unit frame 15a, a swivel bearing 15b, a drive motor 15c, an electromagnetic brake 15d (corresponding to the brake of the present invention), a first gear 15e, a second gear 15f, a steering motor 15g, and a plurality of chains (not shown).

[0023] The swivel bearing 15b is provided in the center of the drive unit frame 15a, and the drive wheel 12 is connected to the drive unit frame 15a via the swivel bearing 15b. The drive motor 15c and the electromagnetic brake 15d are provided adjacent to the drive wheel 12, and the drive motor 15c rotates the drive wheel 12, while the electromagnetic brake 15d stops the rotation of the drive wheel 12. The drive unit frame 15a is formed so as to surround the drive wheel 12, the drive motor 15c, and the electromagnetic brake 15d in a side view. Note that the electromagnetic brake 15d is merely an example, and the brake of the present invention is not limited thereto.

[0024] The first gear 15e is connected to the drive wheels 12, and the second gear 15f is connected to a steering motor 15g. The steering motor 15g is fixed to the drive unit frame 15a and configured to adjust the steering angle of the drive wheels 12 via a chain stretched across the first and second gears 15e, 15f and the first and second gears 15e, 15f.

[0025] As shown in Fig. 1A, the loading device 16 has a mast 16a and a fork 16b. The fork 16b is configured to rise and fall along the mast 16a, and lifts and lowers the fork 16b to scoop up and place a load. As shown in Figs. 1A and 1B, the loading device 16 is also configured to be movable in the front-rear direction. The loading device 16 is configured to operate by hydraulic pressure, but this is merely an example, and the power of the loading device 16 is not limited to this.

[0026] 3 is a functional block diagram of the automated guided vehicle 1. As shown in FIG.

[0027] The hydraulic device 3 is composed of a tank, a pump, a control valve, etc. The hydraulic device 3 is connected to the loading equipment 16, and the control unit 4 is electrically connected to the hydraulic device 3. The control unit 4 operates the hydraulic device 3 to supply and discharge hydraulic oil to and from the loading equipment 16, thereby operating the loading equipment 16.

[0028] The control unit 4 is also electrically connected to the drive motor 15c, the steering motor 15g, and the electromagnetic brake 15d. The control unit 4 controls the drive motor 15c, the steering motor 15g, and the electromagnetic brake 15d to drive and stop the automatic guided vehicle 1 and steer the drive wheels 12.

[0029] <Anti-tip mechanism> Next, the configuration of the tip-over prevention mechanism 2 will be described. Fig. 4 is a schematic plan view showing a part of the tip-over prevention mechanism 2 on the right side of Fig. 1A. Fig. 5 is a front view showing a part of the tip-over prevention mechanism 2, where Fig. 5A shows the state during travel and Fig. 5B shows the state during loading. Fig. 6 is a perspective view showing a part of the tip-over prevention mechanism 2.

[0030] As shown in FIG. 1, anti-tip mechanisms 2 are provided on the left and right sides of the automatic guided vehicle 1, and each anti-tip mechanism 2 has a link 20 (20a, 20b), a horizontal portion 21 (21a, 21b), a support base 22, an adjustment spring 23, a shim 24, a jack unit 25, two guides 26, and a hydraulic cylinder 27, as shown in FIG. 1 and FIG. 4 to FIG. 6.

[0031] The link 20 includes front and rear upper links 20a and front and rear lower links 20b. The front and rear upper links 20a correspond to the "link" of the present invention.

[0032] The front and rear upper links 20a are formed in a V-shape when viewed from the front, and each has a first end and a second end. A chain (not shown) stretched over the first gear 15e is arranged in the front-rear direction above the center of the upper link 20a, and the upper link 20a is prevented from contacting the chain by being formed in a substantially V-shape. The first end is connected to the vehicle body frame 10a via the first rotating shaft 28a so as to be swingable up and down, and the second end is connected to the driving wheel 12 via the drive unit frame 15a. Specifically, the second end is connected to the drive unit frame 15a so as to be swingable via the second rotating shaft 28b.

[0033] As shown in Fig. 5A, the front and rear lower links 20b each extend in the left-right direction and have a first end and a second end. The third end is connected to the body frame 10a via a third rotating shaft 28c so as to be vertically swingable, and the fourth end is connected to the drive unit frame 15a via a fourth rotating shaft 28d so as to be vertically swingable.

[0034] The horizontal portion 21 has a horizontal plate 21a and four ribs 21b. As shown in FIG. 5A, the horizontal plate 21a extends horizontally from a first end of the upper link 20a in a direction opposite to the drive wheel 12. The four ribs 21b are formed in a substantially triangular shape in a front view and stand upright from the horizontal plate 21a. The four ribs 21b are fixed to the first rotating shaft 28a and connected to the first end of the upper link 20a. This allows the horizontal plate 21a to swing up and down around the first rotating shaft 28a as a fulcrum, and when the horizontal plate 21a swings downward, the upper link 20a swings upward around the first rotating shaft 28a as a fulcrum.

[0035] The support base 22 extends horizontally from the body frame 10a, and an adjustment spring 23 (23a) is disposed on the support base 22, extending vertically. The adjustment spring 23 is composed of four springs 23a, but this is merely an example, and the number of springs 23a is not particularly limited. A horizontal plate 21a is seated on the upper end of the adjustment spring 23, and the adjustment spring 23 biases the horizontal plate 21a upward. By biasing the horizontal plate 21a upward, the upper link 20a is swung downward about the first rotating shaft 28a as a fulcrum, and as a result, the drive wheel 12 is pressed against the ground.

[0036] In this way, the automated guided vehicle 1 prevents the wheel load of the driving wheels 12 from exceeding the floor load limit by distributing and supporting the total weight of the automated guided vehicle 1 with the four driven wheels 14, and the driving wheels 12 are appropriately pressed against the ground by the biasing force of the adjustment springs 23. Note that several shims 24 for adjusting the biasing force of the adjustment springs 23 (i.e., the pressing force pressing the driving wheels 12) are arranged below the four springs 23a. However, adjusting the biasing force with the shims 24 is merely an example, and the method of adjusting the biasing force of the adjustment springs 23 is not limited to this, and the tip-over prevention mechanism 2 does not have to include the shims 24.

[0037] The jack unit 25 has a jack body (not shown) and a jack arm (not shown) that expands and contracts up and down. The jack unit 25 is disposed forward of the driven wheels 14 as shown in Fig. 1, and is connected to the hydraulic device 3 as shown in Fig. 3. The jack unit 25 is configured to be able to press the jack arm against the ground.

[0038] The two guides 26 are formed in a generally U-shape when viewed from the front, with an open upper portion, and are fixed to the upper surface of the horizontal plate 21a at a distance from each other in the front and rear directions. The two guides 26 are configured to guide the shaft 27c, which will be described later, in the up and down direction.

[0039] The hydraulic cylinder 27 has a cylinder tube 27a, a piston rod 27b, and a shaft 27c, and is fixed to the vehicle body frame 10a via a bracket 27d. The shaft 27c extends in the front-rear direction, is fixed to the tip of the piston rod 27b, and is disposed inside the U-shaped portion of the front and rear guides 26. The hydraulic cylinder 27 is connected to the hydraulic device 3, and is configured to be able to push the horizontal plate 21a downward by lowering the shaft 27c by supplying and discharging hydraulic oil by the hydraulic device 3. As a result, as shown in FIG. 5B, the hydraulic cylinder 27 is configured to push the horizontal plate 21a downward via the guide 26 by the shaft 27c, thereby swinging the upper link 20a upward about the first rotating shaft 28a as a fulcrum, and lifting the drive wheel 12 off the ground. In addition, the hydraulic cylinder 27 is configured to retract the piston rod 27b and not push the horizontal plate 21a downward when the automatic guided vehicle 1 is traveling.

[0040] <Operation of the anti-tip mechanism> Next, the operation of the tip-over prevention mechanism 2 will be described.

[0041] (1) When traveling, the anti-toppling mechanism 2 retracts the jack arm to lift the jack arm off the ground, and also retracts the piston rod 27b to lift the shaft 27c off the guide 26, as shown in FIG. 5A, allowing the automatic guided vehicle 1 to travel.

[0042] (2) Next, when the automated guided vehicle 1 arrives at the loading position, the tip-over prevention mechanism 2 extends the jack arm and presses the jack arm against the ground.

[0043] (3) Next, as shown in FIG. 5B, the tip-over prevention mechanism 2 extends the piston rod 27b and pushes down the horizontal plate 21a to lift the drive wheels 12 off the ground. As a result, the weight of the automated guided vehicle 1 is supported by the four driven wheels 14 and the two jack units 25. In this state, the control unit 4 moves the loading device 16 forward and raises and lowers the fork 16b to perform loading and unloading work. During loading and unloading work, because the drive wheels 12 are lifted off the ground and the jack units 25 are positioned forward of the driven wheels 14, the vehicle body 10 is prevented from tilting forward even if the loading and unloading device 16 moves forward of the vehicle body 10.

[0044] (4) When the loading / unloading operation is completed and the loading / unloading device 16 is stored in the vehicle body 10 by the control unit 4, the tip-over prevention mechanism 2 retracts the jack arm and the piston rod 27b, thereby pressing the drive wheels 12 against the ground again.

[0045] In this way, the tip-over prevention mechanism 2 distributes the vehicle weight between the four driven wheels 14 and the two driving wheels 12 during travel, preventing the wheel load from exceeding the floor load limit. In addition, the wheel load of the driving wheels 12 is adjusted by the adjustment spring 23, so it is not affected by the weight of the load during loading. Moreover, the tip-over prevention mechanism 2 completely prevents tipping from being promoted by the pressing force of the driving wheels 12 by completely lifting the driving wheels 12 during loading. Therefore, the automated guided vehicle 1 equipped with the tip-over prevention mechanism 2 according to the present invention will not tip over even if the loading device 16 is moved forward of the vehicle body 10. As a result, the automated guided vehicle 1 can properly perform loading and unloading work even in places where the floor load is limited.

[0046] Although the fall prevention mechanism 2 and the automated guided vehicle 1 according to one embodiment of the present invention have been described above, the fall prevention mechanism 2 and the automated guided vehicle 1 of the present invention are not limited to the above embodiment. For example, the present invention may be embodied in the following modified examples.

[0047] <Modification> The tip-over prevention mechanism 2 does not necessarily have to be configured to lift the drive wheels 12 during loading and unloading, so long as the pressing force on the drive wheels 12 can be reduced to a level that can prevent tipping of the automated guided vehicle 1 during loading and unloading. In other words, the actuator (hydraulic cylinder 27) of the present invention may be configured to reduce the pressing force on the drive wheels 12 to a level that can prevent tipping of the automated guided vehicle 1 during loading and unloading.

[0048] The actuator of the present invention is not limited to the hydraulic cylinder 27. For example, the actuator may be an electric or electromagnetic type as long as it can press the horizontal plate 21a downward.

[0049] The actuator of the present invention may be configured to be able to press down the horizontal plate 21a with any force in order to adjust the pressing force on the drive wheels 12 while traveling. In this case, the automated guided vehicle 1 can adjust the pressing force on the drive wheels 12 according to the condition of the ground without using the shim 24.

[0050] The tip-over prevention mechanism 2 does not necessarily have to lift the drive unit 15 together with the drive wheels 12 as long as the pressing force against the drive wheels 12 can be reduced during loading and unloading. For example, the tip-over prevention mechanism 2 may be configured to lift the drive wheels 12 independently during loading and unloading. [Explanation of symbols]

[0051] 1. Automated guided vehicle 10. Body 10a Body frame 12 Drive wheels 14 Driven Wheel 15 Drive unit 15a Drive unit frame 15b Swivel bearing 15c Drive motor 15d Electromagnetic brake 15e 1st Gear 15f 2nd Gear 15g steering motor 16 Cargo handling equipment 16a Mast 16b fork 2 Anti-tip mechanism 20 Links 20a upper link 20b Lower link 21 Horizontal part 21a Horizontal plate 21b Rib 22 Support stand 23 Adjustment spring 23a Spring 24 Sim 25 Jack unit 26 Guide 27 Hydraulic cylinder (actuator) 27a Cylinder tube 27b Piston rod 27c shaft 27d Bracket 28a First Rotation Axis 28b Second rotation axis 28c 3rd rotation axis 28d 4th rotation axis 3. Hydraulic system 4. Control section

Claims

1. A tip-over prevention mechanism provided in an automated guided vehicle, The automated guided vehicle is a vehicle body having left and right vehicle body frames extending vertically; Driven wheels arranged at the front, rear, left and right of the vehicle body; Left and right drive wheels respectively disposed between the front and rear driven wheels; A loading device configured to be movable in the forward and backward directions, The tip-over prevention mechanism includes: The automatic guided vehicle is provided on the left and right sides, front and rear links each having a first end connected to the body frame via a rotating shaft so as to be swingable up and down and a second end connected to the drive wheel; a horizontal portion having a horizontal plate extending from the rotation shaft in a direction opposite to the drive wheel and configured to be swingable about the rotation shaft; an adjustment spring configured to urge the horizontal plate upward and swing the front and rear links downward to press the drive wheels against the ground; an actuator fixed to the vehicle body frame and configured to be able to push the horizontal plate downward; The actuator is configured to push the horizontal plate downward during loading and unloading to reduce the pressing force against the drive wheels, thereby preventing overturning.

2. The tip-over prevention mechanism according to claim 1 , wherein the actuator is configured to push the horizontal plate downward to completely lift the drive wheels off the ground when the automated guided vehicle is loading and unloading.

3. The tip-over prevention mechanism according to claim 1 , wherein the actuator is configured not to press down the horizontal plate when the automated guided vehicle is traveling.

4. The vehicle further includes left and right jack units each having a jack body and a jack arm, the jack arm being configured to be capable of pressing the jack arm against the ground, and disposed forward of the driven wheels; The anti-tip mechanism according to any one of claims 1 to 3, wherein the jack arm is configured to be lifted off the ground when the automated guided vehicle is traveling and to press against the ground when the automated guided vehicle is loading and unloading.

5. The tip-over prevention mechanism according to claim 1 , wherein the actuator comprises a hydraulic cylinder.

6. The actuator has a shaft extending horizontally, The tip-over prevention mechanism further includes a guide fixed to the horizontal plate for guiding the shaft in an up-down direction, The anti-tip mechanism of claim 1 , wherein the actuator is configured to push the horizontal plate downward by lowering the shaft.

7. The automated guided vehicle further includes a drive unit, The front and rear links are connected to the drive wheels via the drive unit, The anti-tip mechanism of claim 1 , wherein the drive unit is configured to be raised and lowered together with the drive wheels.

8. The drive unit includes a drive unit frame, a drive motor, a brake, a steering motor, and a slewing bearing. The tip-over prevention mechanism according to claim 7 , wherein the front and rear links are connected to the drive wheels via the drive unit frame.

9. The anti-tip mechanism according to claim 1 , wherein the loading device has a mast and a fork.

10. An automated guided vehicle comprising the fall prevention mechanism according to claim 1.

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