Automated guided vehicle

Abstract

To enhance traveling performance to a travel surface of an automated guided vehicle traveling on the travel surface vertically and horizontally.SOLUTION: An automated guided vehicle 1 includes a plurality of first travel wheels 11 whose axle direction is a cross direction, a plurality of second travel wheels 12 whose axle direction is a longitudinal direction, and a travel wheel switching mechanism C for making one of the first travel wheels 11 and the second travel wheels 12 ground to a travel surface G and the other float. The automated guided vehicle 1 has a frame body 8 having an intermediate position supported by a longitudinal axle 10 and extending in a longitudinal pair of cross directions swinging around the longitudinal axle 10. In traveling by the second travel wheels 12, the second travel wheels 12 can move vertically correspondingly to the travel surface G. The vehicle includes frame body swing regulation means A for regulating swinging around the longitudinal axle 10 of the frame body 8 when the travel wheel switching mechanism C makes the first travel wheels 11 ground to the travel surface G and the second travel wheels 12 float.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an automated guided vehicle that travels longitudinally and laterally on a travel surface. [Background technology]

[0002] A conventional unmanned guided vehicle that travels vertically and horizontally on a running surface is equipped with a plurality of first running wheels whose axles run in the front-to-back direction, a plurality of second running wheels whose axles run in the left-to-right direction, and a running wheel switching mechanism that brings one of the first running wheels or the second running wheels into contact with the running surface and keeps the other off the ground (see, for example, Patent Document 1).

[0003] For example, the article moving device 3 in Patent Document 1 includes a plurality of X-direction running wheels 38 whose axles are oriented in the Y direction, a plurality of Y-direction running wheels 48 whose axles are oriented in the X direction, and a running wheel lifting means (see running wheel lifting means 40 in FIG. 10 for the X-direction running wheels 38) that switches between a state in which the X-direction running wheels 38 are in contact with the running surface and the Y-direction running wheels 48 are lifted as shown in FIG. 13(a) and a state in which the Y-direction running wheels 48 are in contact with the running surface and the X-direction running wheels 38 are lifted as shown in FIG. 13(b).

[0004] An example of such an unmanned guided vehicle is an unmanned guided vehicle that travels vertically and horizontally within a limited area of ​​a shelf system having an item storage space in an automated warehouse or the like, and slips under item support members in the shelf system on which items are placed to transport items in or out in order to increase the storage capacity inside the shelf system (see, for example, Patent Document 1).

[0005] For example, the item moving device 3 in Patent Document 1 is a low-floor type with a low overall height, as it moves in and out of the item W by slipping under the item support members 16a, 16b in the compartment separated by the pillars 12a, 12b, 12c, 12d in Figures 3 and 11 in the storage area 7 in Figure 2. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 6845980 Summary of the Invention [Problem to be solved by the invention]

[0007] An automated guided vehicle that travels vertically and horizontally on a running surface may be configured to also travel on the ground outside the shelf equipment, and the running surface on the ground may have parts where the inclination angle changes or be uneven.

[0008] The inventors of the present application attempted to run the automated guided vehicle on a running surface having a portion where the inclination angle changes and an uneven surface. As a result, a problem with the automated guided vehicle was revealed, in that the running ability of the automated guided vehicle was reduced on a running surface having a portion where the inclination angle changes and an uneven surface. In particular, when the automated guided vehicle is of the low-floor type, coupled with the small diameter of the running wheels, the decrease in running ability on a running surface having a portion where the inclination angle changes and an uneven surface becomes significant.

[0009] The present invention aims to improve the traversal ability of an unmanned guided vehicle that travels vertically and horizontally on a traveling surface, on a traveling surface having portions where the inclination angle changes or unevenness. [Means for solving the problem]

[0010] An automated guided vehicle according to a first aspect of the present invention includes a plurality of first running wheels whose axles are oriented in the front-rear direction, a plurality of second running wheels whose axles are oriented in the left-right direction, and a running wheel switching mechanism that brings one of the first running wheels and the second running wheels into contact with a running surface and keeps the other one off the ground. The automated guided vehicle has a pair of left and right frame bodies that extend in the front-rear direction and are supported at an intermediate position by a left-right support shaft and swing around the left-right support shaft, and parts of the second running wheels are disposed at the front and rear ends of the frame bodies. The automated guided vehicle includes a frame body swing restriction means that restricts the swing of the frame body around the left-right support shaft when the running wheel switching mechanism brings the first running wheels into contact with the running surface and keeps the second running wheels off the ground.

[0011] According to the configuration of the unmanned guided vehicle of the first aspect, the running wheel switching mechanism causes one of the first running wheel and the second running wheel to contact the running surface and the other to be raised off the ground, thereby allowing the vehicle to run vertically and horizontally on the running surface.

[0012] According to the configuration of the automated guided vehicle according to the first aspect, the automated guided vehicle has a pair of left and right frame bodies extending in the front-rear direction that swing about a left-right support shaft, and a part of the second running wheels is disposed at the front end and the rear end of the frame bodies. Therefore, when the automated guided vehicle runs on the second running wheels, even if the running surface has a portion where the inclination angle changes or is uneven, the pair of left and right frame bodies disposed at the front end and the rear end of the second running wheels swing individually, and the second running wheels can move in the up-down direction in response to the running surface, thereby improving the running ability on the running surface.

[0013] According to the configuration of the automated guided vehicle according to the first aspect, when the running wheel switching mechanism brings the first running wheels into contact with the running surface and raises the second running wheels above the running surface, the frame body swing restriction means restricts swinging of the frame body, on whose front and rear ends the second running wheels are arranged, about the left-right support shafts. Therefore, the frame body does not swing with the second running wheels raised above the running surface, causing the minimum ground clearance to decrease, and the required minimum ground clearance can be maintained.

[0014] An unmanned guided vehicle according to a second aspect of the present invention is the unmanned guided vehicle according to the first aspect, wherein the frame body sway control means controls the swaying of the frame body when the second running wheel is raised, in conjunction with the raising and lowering action of the second running wheel by the running wheel switching mechanism, and releases the control on the swaying of the frame body when the second running wheel is lowered.

[0015] According to the configuration of the unmanned guided vehicle relating to the second aspect, the frame body swaying control means, which is linked to the raising and lowering action of the second running wheel by the running wheel switching mechanism, controls the swaying of the frame body when the second running wheel is raised and releases the restriction on the swaying of the frame body when the second running wheel is lowered. Therefore, there is no need to provide a large-scale device for restricting and releasing the swaying of the frame body, and the configuration of the frame body swaying control means is simplified.

[0016] An automated guided vehicle according to a third aspect of the present invention is the automated guided vehicle according to the second aspect, wherein the frame body sway regulating means is a positioning portion provided on a base body side supporting the first running wheels and abutting the frame body from above. The positioning portion is arranged behind the left-right support shaft when the frame body tilts forward about the left-right support shaft when the second running wheels arranged at the front and rear ends of the frame body lift off the running surface, and is arranged in front of the left-right support shaft when the frame body tilts backward about the left-right support shaft when the second running wheels arranged at the front and rear ends of the frame body lift off the running surface.

[0017] According to the configuration of the unmanned guided vehicle relating to the third aspect, the frame body sway control means, which is linked to the raising and lowering action of the second running wheel by the running wheel switching mechanism, is a positioning portion provided on the base side supporting the first running wheel, abutting the frame body from above and positioned at either the front or rear of the left-right support axis, making the configuration of the frame body sway control means even simpler.

[0018] An unmanned guided vehicle according to a fourth aspect of the present invention is the unmanned guided vehicle according to the second aspect, wherein the frame body sway control means is a positioning portion provided on a base body side supporting the first running wheel and abuts the frame body from above, and the positioning portions are arranged in front and behind the left-right support shaft.

[0019] According to the configuration of the unmanned guided vehicle relating to the fourth aspect, the frame body sway control means, which is linked to the raising and lowering operation of the second running wheel by the running wheel switching mechanism, is a positioning portion provided on the base side supporting the first running wheel, which abuts the frame body from above and is arranged both in front of and behind the left-right support shaft, so that swinging of the frame body around the left-right support shaft can be reliably prevented.

[0020] An automated guided vehicle according to a fifth aspect of the present invention is the automated guided vehicle according to any one of the first to fourth aspects, wherein the automated guided vehicle travels both within a shelf system having an item storage space and on the ground outside the shelf system, and within the shelf system, the automated guided vehicle slips under an item support member on which an item is placed to carry the item in or out. With the swing of the frame body restricted by the frame body swing restricting means, an imaginary plane that contacts from below the second traveling wheels arranged at the front end and the rear end of the frame body becomes approximately horizontal.

[0021] An automated guided vehicle according to a fifth aspect is configured to include a running wheel switching mechanism, a pair of left and right frame bodies extending in the front-rear direction that swing around a left-right support shaft, and second running wheels are arranged at the front and rear ends of the frame bodies. Therefore, when traveling on the ground outside the rack system, the running wheel switching mechanism causes the second running wheels to contact the running surface on the ground and the first running wheels to be raised above the running surface, and the automated guided vehicle travels on the second running wheels, so that even if the running surface has a portion where the inclination angle changes or is uneven, the pair of left and right frame bodies arranged at the front and rear ends of the second running wheels swing individually, and the second running wheels can move in the vertical direction in response to the running surface, thereby improving the running ability on the running surface.

[0022] The automated guided vehicle according to the fifth aspect is a low-floor type with a low overall height because it slips under an article support member on which an article is placed in a shelf system to carry in or out the article. Therefore, it is not possible to increase the lifting stroke when the running wheel switching mechanism brings one of the first running wheel and the second running wheel into contact with the running surface and keeps the other wheel off the ground.

[0023] According to the unmanned guided vehicle of the fifth aspect, the running wheel switching mechanism brings the first running wheel into contact with the running surface and the second running wheel into a floating state, and with the frame body's swinging motion around the left-right support axis restricted by the frame body swinging restriction means, an imaginary plane abutting from below the second running wheels arranged at the front and rear ends of the frame body becomes approximately horizontal.

[0024] Therefore, the frame body sway control means controls the swaying of the frame body around the left-right support axis, so that the frame body does not sway when the second running wheels are lifted off the running surface, thereby preventing the minimum ground clearance from decreasing. Furthermore, with the frame body's swaying controlled, an imaginary plane that abuts from below on the second running wheels arranged at the front and rear ends of the frame body becomes approximately horizontal, so that the required minimum ground clearance can be maintained even in the low-floor type unmanned guided vehicle. Effect of the Invention

[0025] As described above, according to the automatic guided vehicle of the present invention, the automatic guided vehicle that travels vertically and horizontally on a traveling surface can improve its ability to traverse traveling surfaces that have parts with changing inclination angles or unevenness. [Brief description of the drawings]

[0026] [Figure 1] 1 is a schematic plan view of an automated guided vehicle according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a perspective view of the automated guided vehicle, showing a state in which the lift table is lowered. [Diagram 3] FIG. 4 is a perspective view of the automatic guided vehicle, showing a state in which the lift table is raised. [Figure 4] 4 is a schematic cross-sectional view of the automated guided vehicle as viewed from the right, illustrating a state in which the second running wheels are lifted by a running wheel switching mechanism and the first running wheels are brought into contact with the running surface. FIG. [Diagram 5] 4 is a schematic cross-sectional view of the automated guided vehicle as viewed from the right, illustrating a state in which a first running wheel is lifted and a second running wheel is brought into contact with a running surface by a running wheel switching mechanism. FIG. [Figure 6] FIG. 2 is a schematic plan view showing main components of a drive system of the automatic guided vehicle, with a lift table and a cover removed. [Figure 7] 7 is an enlarged view of the main part around the right sub-frame in FIG. 6. [Figure 8] 11 is a schematic view seen from the right, illustrating the swinging of a frame body extending in the front-rear direction. FIG. [Figure 9] 13 is a schematic view showing the frame body rocking restriction means as viewed from the right. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Referring to the reference numerals in the drawings, an automated guided vehicle 1 according to the embodiment of the present invention includes a running wheel switching mechanism C that causes one of a first running wheel 11 and a second running wheel 12 to contact a running surface G and keeps the other in a raised state, and can run vertically and horizontally on the running surface G.

[0028] [Define the direction of the automated guided vehicle] The forward, backward, left and right directions of the automated guided vehicle 1 shown in Fig. 1 are defined as arrow F as the forward direction, arrow B as the backward direction, arrow L as the left direction, and arrow R as the right direction, and the directions also include directions parallel to the directions. For example, "forward" includes the direction of arrow F and a direction parallel to arrow F, and "left" includes the direction of arrow L and a direction parallel to arrow L.

[0029] [Define axle direction] In the following, the axle refers to the rotation axis of the traveling wheels of the automated guided vehicle 1. The driven wheels 15, 16 of the second traveling wheels 12 are swivel wheels and can rotate freely around a vertical axis, so the direction of the axles 15A, 16A relative to the vehicle body 2 varies depending on the state in which the automated guided vehicle 1 is traveling.

[0030] 1, that is, for example, the first running wheel 11 is lifted by the running wheel switching mechanism C, the second running wheel 12 is grounded on the running surface G, and the left and right drive wheels 14 of the second running wheel 12 are rotated in the same direction at a uniform speed, so that the automated guided vehicle 1 moves forward F. In this standard state, the direction of the axles 15A, 16A of the driven wheels 15, 16 is the same left-right direction as the direction of the axle 14A of the drive wheel 14.

[0031] [Automated guided vehicle] As shown in Fig. 1, an automated guided vehicle 1 according to an embodiment of the present invention includes a plurality of first running wheels 11 with axles 13A oriented in the front-rear direction, and a plurality of second running wheels 12 with axles 14A, 15A, 16A oriented in the left-right direction. The first running wheels 11 are, for example, four driving wheels 13 arranged in the front, rear, left and right directions. The second running wheels 12 are, for example, two driving wheels 14 (left and right), two driven wheels 15 (left and right), and two driven wheels 16 (left and right).

[0032] Among the second traveling wheels 12, the driven wheels 15 and the driving wheels 14 are disposed at the front and rear ends of a pair of left and right frame bodies 7, 8 extending in the front-rear direction. In other words, parts of the second traveling wheels 12 are disposed at the front and rear ends of the frame bodies 7, 8. The frame bodies 7, 8 are supported at their front-rear intermediate positions by left and right support shafts 9, 10, so that they swing individually about the left and right support shafts 9, 10.

[0033] The pair of left and right frame bodies 7, 8 is not limited to one pair, and two or more pairs may be provided. Two pairs of frame bodies, i.e., two pairs of left and right frame bodies, may be provided, and the second running wheels 12 may be arranged at the front and rear ends of the frame bodies, and the second running wheels 12 may not be arranged on any other frame bodies than the two pairs of left and right frame bodies. Even in such a case, a part of the second running wheels is arranged at the front and rear ends of the pair of left and right frame bodies.

[0034] In addition to the pair of left and right frame bodies 7, 8 extending in the front-rear direction, a pair of front and rear second frame bodies extending in the left-right direction may be provided. The second frame bodies are supported at their left-right intermediate positions by a front-rear support shaft, and swing individually around the front-rear support shaft. First running wheels 11 are disposed on the left and right ends of the second frame body. The number of the second frame bodies is also not limited to one, and two or more sets may be provided.

[0035] The drive wheels 14 of the second traveling wheels 12 may not be disposed on the frame bodies 7, 8, and driven wheels may be disposed on both the front and rear ends of the frame bodies 7, 8. The drive wheels 14 are not limited to a pair of left and right wheels, and may be, for example, two or more pairs of left and right wheels. However, by disposing the drive wheels 14 as a pair of left and right wheels in the center of the front-rear direction of the vehicle body 2 as shown in FIG. 1 of this embodiment, the turning radius can be reduced when making a spin turn (turning on the spot) by rotating the left and right drive wheels 14 in opposite directions at a uniform speed.

[0036] The automated guided vehicle 1 is generally rectangular in plan view and has a main frame 3 that constitutes a vehicle body 2, left and right sub-frames 4 and 5, and a lifting table 6, etc., and the sub-frames 4 and 5 and the lifting table 6 are supported by the main frame 3 so that they can be raised and lowered. Horizontal guide rollers H that protrude to the left are provided at the front and rear ends of the left sub-frame 4, and horizontal guide rollers H that protrude to the right are provided at the front and rear ends of the right sub-frame 5.

[0037] In this embodiment, the automated guided vehicle 1 is a low-floor type with a low overall height, and can be in a state in which the lift table 6 is lowered as shown in Fig. 2, and in a state in which the lift table 6 is raised as shown in Fig. 3. The lift table 6 is for supporting and transporting an article from below.

[0038] The low-floor automated guided vehicle 1 travels both within a shelf system having an item storage space and on the ground outside the shelf system, and within the shelf system, it is suitable for slipping under an item support member on which an item is placed to carry the item in or out. The automated guided vehicle 1 may be one that travels only on the ground outside the shelf system, and is suitable for slipping under a cart or pallet stand on the ground outside the shelf system to carry out required work. Note that "ground" includes not only above the ground, but also above the floor surface, etc.

[0039] The automated guided vehicle 1 includes the running wheel switching mechanism C as described above, and can use the running wheel switching mechanism C to switch between a state in which the second running wheels 12 are lifted and the first running wheels 11 are in contact with the running surface G as shown in Fig. 4 and a state in which the first running wheels 11 are lifted and the second running wheels 12 are in contact with the running surface G as shown in Fig. 5. The automated guided vehicle 1 runs on the first running wheels 11 when the first running wheels 11 are in contact with the running surface G, and runs on the second running wheels 12 when the second running wheels 12 are in contact with the running surface G.

[0040] [Drive system configuration example] Please refer to the schematic plan view of Fig. 6, which shows the state where the lift table 6 and covers I and J of Figs. 1 to 3 are removed. Fig. 6 shows the main components of the drive system of the automatic guided vehicle 1. The main frame 3 is equipped with traveling drive devices M1 and M2, a traveling wheel switching mechanism drive device M3, and a lift drive device M4. These drive devices M1, M2, M3, and M4 are, for example, geared motors.

[0041] (Drive system using traveling drive unit) The traveling drive unit M1 drives two driving wheels 13, a left front and a left rear, among the first traveling wheels 11, and a left driving wheel 14, among the second traveling wheels 12. The traveling drive unit M2 drives two driving wheels 13, a right front and a right rear, among the first traveling wheels 11, and a right driving wheel 14, among the second traveling wheels 12.

[0042] First, the mechanism for transmitting the drive torque of the traveling drive unit M2 will be described with reference mainly to Fig. 7. The drive torque of the traveling drive unit M2 is transmitted to the second shaft portion S2 in the front-rear direction by the spur gears 26A and 26B, causing the second shaft portion S2 to rotate. The rotation of the second shaft portion S2 causes the two drive wheels 13, the right front and right rear, to rotate.

[0043] Additionally, bevel gear 27A attached to the middle of second shaft portion S2 in the front-rear direction rotates bevel gear 27B, which rotates left-right shaft 28. The rotation of shaft 28 transmits driving torque via sprocket 29A, chain 30, and sprocket 29B, also shown in Figures 4 and 5, causing rotation of right driving wheel 14. Tension roller 31 is elastically biased on chain 30, ensuring tension in chain 30.

[0044] The driving torque of the traveling drive unit M1 is transmitted to the first axle portion S1 in the front-to-rear direction by a transmission mechanism similar to the transmission mechanism of the driving torque of the traveling drive unit M2, causing the two driving wheels 13, the left front and left rear, and the left driving wheel 14 to rotate.

[0045] (Drive system of running wheel switching mechanism drive device) The traveling wheel switching mechanism drive device M3 shown in FIG. 6 is a dual output type, and its driving torque is transmitted to the third left shaft portion S3A and the third right shaft portion S3B, thereby driving the left front switching cam D1 and the right front switching cam D3.

[0046] The driving torque is transmitted by the sprocket 32A attached to the third left shaft portion S3A, the chain 33, and the sprocket 32B, thereby driving the left rear switching cam D2. The tension of the chain 33 can be adjusted by the idler sprockets 34A and 34B.

[0047] The drive torque is transmitted through the sprocket 35A attached to the third right shaft portion S3B, the chain 36, and the sprocket 35B, thereby driving the right rear switching cam D4. The tension of the chain 36 can be adjusted by the idler sprockets 37A and 37B.

[0048] As described above, the switching cams D1 to D4 can be rotated by driving the traveling wheel switching mechanism drive device M3.

[0049] When the switching cams D3 and D4 are in the rotational position shown in Figure 4 (the rotational positions of the switching cams D1 and D2 are similar), the roller 23 pushes up the hanger 25, causing the sub-frame body 5 (similar to the sub-frame body 4) to rise relative to the main frame body 3, lifting the second running wheel 12 and causing the first running wheel 11 to contact the running surface G.

[0050] In contrast, in the rotational positions of the switching cams D3, D4 shown in Figure 5 (the rotational positions of the switching cams D1, D2 are similar), the cam follower 24 is pushed down by the switching cams D1 to D4, so that the sub-frame body 5 (similar to the sub-frame body 4) descends relative to the main frame body 3, lifting the first running wheel 11 and causing the second running wheel 12 to contact the running surface G.

[0051] The running wheel switching mechanism drive device M3 and its drive system configuration as described above, as well as the switching cams D1 to D4, the roller 23, the hanger 25, and the cam follower 24, constitute a running wheel switching mechanism C that brings one of the first running wheel 11 and the second running wheel 12 into contact with the ground and keeps the other lifted.

[0052] (Drive system for lifting drive device) The driving torque of the lifting / lowering drive device M4 shown in FIG. 6 is transmitted to the fourth shaft portion S4 in the front-rear direction by the spur gears 38A, 38B, thereby driving the left front lifting cam E1 and the left rear lifting cam E3.

[0053] The drive torque is transmitted by sprocket 39A attached to the front of the fourth shaft portion S4, chain 40, and sprocket 39B, driving the right front lift cam E2. The tension of the chain 40 can be adjusted by idler sprockets 41A and 41B.

[0054] The drive torque is transmitted by a sprocket 42A attached to the rear of the fourth shaft portion S4, a chain 43, and a sprocket 42B, which drives the right rear lift cam E4. The tension of the chain 43 can be adjusted by idler sprockets 44A and 44B.

[0055] As described above, the lift cams E1 to E4 can be rotated by driving the lift drive device M4, whereby the lift table 6 can be lowered as shown in FIG. 2 and raised as shown in FIG.

[0056] [Frame body and second running wheels arranged at the front and rear of the frame body] Referring to FIG. 1, as described above, the automated guided vehicle 1 has a pair of left and right frame bodies 7, 8 that swing independently around left and right support axes 9, 10, and second running wheels 12 are arranged on the front and rear ends of the frame bodies 7, 8.

[0057] As a result, when the vehicle travels on the second running wheels 12 with the first running wheels 11 raised and the second running wheels 12 in contact with the running surface G by the running wheel switching mechanism C as shown in Fig. 5, the right frame body 8 swings about the left-right support shaft 10 in accordance with the running surface G, as shown in Fig. 8, and the second running wheels 12 at the front and rear of the right frame body 8 can move up and down. Similarly, the left frame body 7 swings about the left-right support shaft 9 separately from the right frame body 8 in accordance with the running surface G, and the second running wheels 12 at the front and rear of the left frame body 7 can move up and down.

[0058] Therefore, when the second running wheel 12 runs on the running surface G, even if the running surface G has a portion where the inclination angle changes or is uneven, the running performance on the running surface G can be improved.

[0059] When the second running wheels 12 run on the running surface G, even if the running surface G is a horizontal surface without any unevenness, if the second running wheels 12 of the automated guided vehicle 1 have four or more wheels (three wheels can stably touch the ground) as in this embodiment, it may be difficult to bring all the wheels into contact with the ground due to manufacturing errors in wheel attachment, etc. Even in such a case, by arranging the running wheels 12 at the front and rear ends of the pair of left and right frame bodies 7, 8 that swing independently about the left and right support shafts 9, 10, all the wheels can be brought into contact with the ground.

[0060] [Frame body rocking restriction means] The unmanned guided vehicle 1 is equipped with a frame body sway control means A that controls the swaying of the frame bodies 7, 8 around the left-right support axes 9, 10 when changing from a state in which the first running wheel 11 is lifted by the running wheel switching mechanism C and the second running wheel 12 is in contact with the running surface G as shown in Figure 5 to a state in which the second running wheel 12 is lifted by the running wheel switching mechanism C and the first running wheel 11 is in contact with the running surface G as shown in Figure 4.

[0061] The frame body swaying restriction means A is, for example, positioning portions P1, P2 that are provided on the main frame 3, which is the base body N that supports the first running wheel 11, and contact the frame bodies 7, 8 from above, as shown in Figures 6 and 9. The positioning portion P1 is disposed in front of the left-right support shafts 9, 10 (see also Figure 1), and the positioning portion P2 is disposed behind the left-right support shafts 9, 10.

[0062] The positioning portion P1 is a vertical bolt 21A that screws into a screw hole in the horizontal plate portion 19A of the support bracket 19, and a nut 21B that screws into the bolt 21A and abuts against the upper surface of the horizontal plate portion 19A. With the nut 21B loosened, the bolt 21A is rotated to adjust the length of the threaded portion that protrudes downward from the lower surface of the horizontal plate portion 19A (the position of the tip T1 of the threaded portion of the bolt 21A). After adjusting the position of the tip T1 of the threaded portion of the bolt 21A, the nut 21B is tightened and pressed against the upper surface of the horizontal plate portion 19A, thereby fixing the position of the bolt 21A relative to the support bracket 19.

[0063] The positioning portion P2 is a vertical bolt 22A that screws into a screw hole in the horizontal plate portion 20A of the support bracket 20, and a nut 22B that screws into the bolt 22A and abuts against the upper surface of the horizontal plate portion 20A. With the nut 22B loosened, the bolt 22A is rotated to adjust the length of the threaded portion that protrudes downward from the lower surface of the horizontal plate portion 20A (the position of the tip T2 of the threaded portion of the bolt 22A). After adjusting the position of the tip T2 of the threaded portion of the bolt 22A, the nut 22B is tightened and pressed against the upper surface of the horizontal plate portion 20A, thereby fixing the position of the bolt 22A relative to the support bracket 20.

[0064] When the running wheel switching mechanism C switches from the state shown in Fig. 5 to the state shown in Fig. 4 and the second running wheel 12 rises, as shown in Fig. 9, the tip T1 of the threaded portion of the bolt 21A approaches the upper surface 17A of the front end support 17 of the frame bodies 7, 8, and the tip T2 of the threaded portion of the bolt 22A approaches the upper surface 18A of the rear end support 18 of the frame bodies 7, 8. In this state, the swing of the frame bodies 7, 8 around the left-right support shafts 9, 10 is restricted, and the frame body swing restriction means A is in an operating state.

[0065] 9, the positions of the bolts 21A and 22A are adjusted so that the front opposing surface between the tip T1 of the threaded portion of the bolt 21A and the upper surface 17A of the front end support 17, and the rear opposing surface between the tip T2 of the threaded portion of the bolt 22A and the upper surface 18A of the rear end support 18 are not in contact with each other. This prevents overload when the frame body rocking restriction means A is activated.

[0066] An elastic material such as rubber may be provided on the tip T1 of the threaded portion of the bolt 21A on the front opposing surface or the upper surface 17A of the front end support 17, and the tip T2 of the threaded portion of the bolt 22A on the rear opposing surface or the upper surface 18A of the rear end support 18. In this case, in the operating state of the frame body rocking restriction means A shown in Fig. 9, the tip T1 of the threaded portion of the bolt 21A and the upper surface 17A of the front end support 17 are brought into contact with each other via the elastic material, and the tip T2 of the threaded portion of the bolt 22A and the upper surface 18A of the rear end support 18 are brought into contact with each other via the elastic material. This prevents overload caused by deformation of the elastic material, while eliminating rattling of the frame bodies 7 and 8, thereby preventing noise and the like generated by the first traveling wheel 11 during traveling.

[0067] 5 by the running wheel switching mechanism C, and the second running wheel 12 descends, the tip T1 of the threaded portion of the bolt 21A moves away from the upper surface 17A of the front end support 17 of the frame bodies 7, 8, and the tip T2 of the threaded portion of the bolt 22A moves away from the upper surface 18A of the rear end support 18 of the frame bodies 7, 8. In this state, the restriction on the swinging of the frame bodies 7, 8 about the left-right support shafts 9, 10 is released, and the frame body swing restriction means A is in a non-operating state.

[0068] As described above, the frame body rocking restriction means A restricts the rocking of the frame bodies 7, 8 about the left and right support shafts 9, 10 when the second running wheel 12 is raised in conjunction with the raising and lowering operation of the second running wheel by the running wheel switching mechanism C, and releases the restriction on the rocking of the frame bodies 7, 8 when the second running wheel 12 is lowered. With this configuration, there is no need to provide a large-scale device for restricting and releasing the rocking of the frame bodies 7, 8, and the configuration of the frame body rocking restriction means A is simplified.

[0069] Furthermore, by configuring the frame body rocking restriction means A by positioning portions P1, P2 arranged on both the front F and rear B of the left-right support shafts 9, 10 which abut against the frame bodies 7, 8 from above, as shown in Figures 6 and 9, it is possible to reliably prevent the frame bodies 7, 8 from rocking around the left-right support shafts 9, 10.

[0070] In the above description, the positioning portions P1, P2 are provided on both the front F and rear B of the left-right support shafts 9, 10. However, a positioning portion may be provided on only one of the front F and rear B of the left-right support shafts 9, 10.

[0071] In such a configuration, if the frame bodies 7, 8 tilt backward around the left-right support shafts 9, 10 when the second running wheels 12 arranged at the front and rear ends of the frame bodies 7, 8 lift off the running surface G, the positioning portion P1 is arranged at the front F of the left-right support shafts 9, 10. In this embodiment, the frame bodies 7, 8 have a driving wheel 14 at the rear end thereof, which is heavier than the driven wheel 15 at the front end thereof, and therefore corresponds to the case where the frame bodies 7, 8 tilt backward. In addition, if the frame bodies 7, 8 tilt forward around the left-right support shafts 9, 10 when the second running wheels 12 arranged at the front and rear ends thereof lift off the running surface G, the positioning portion P2 is arranged at the rear B of the left-right support shafts 9, 10.

[0072] By providing a positioning portion only on one of the front F and rear B of the left-right support shafts 9, 10 to form the frame body rocking restriction means A, the structure of the frame body rocking restriction means A becomes even simpler.

[0073] The configuration of the frame body sway control means A is not limited to the positioning portions P1 and / or P2 described above, but may be any means that has the function of controlling the swaying of the frame bodies 7, 8 around the left-right support axes 9, 10 when the running wheel switching mechanism C grounds the first running wheel 11 on the running surface G and raises the second running wheel 12 off the ground.

[0074] For example, in this embodiment, the frame bodies 7, 8 have driving wheels 14 at their rear ends, which are heavier than the driven wheels 15 at their front ends, and therefore when the second running wheel 12 is lifted off the running surface G, the frame bodies 7, 8 will tilt backward about the left-right support shafts 9, 10, so a configuration may be adopted in which a position B behind the left-right support shafts 9, 10 of the frame bodies 7, 8 is pulled up by an elastic biasing force of a tension coil spring or the like. In that case, when the running wheel switching mechanism C brings the first running wheel 11 into contact with the running surface G to lift the second running wheel 12 off the running surface G, a positioning portion is brought into contact with the rear B of the left-right support shafts 9, 10 of the frame bodies 7, 8 that have been lifted up by the elastic biasing force, and this serves as the frame body rocking restriction means A.

[0075] Alternatively, when the second running wheel 12 is raised, a mechanism may be provided that locks between the left and right support shafts 9, 10 and the frame bodies 7, 8 at any time from before the second running wheel 12 is raised to when it is completed, and this mechanism serves as a frame body sway control means A.

[0076] By providing the frame body sway restriction means A as described above to the automatic guided vehicle 1, when the running wheel switching mechanism C brings the first running wheel 11 into contact with the running surface G and raises the second running wheel 12 above the running surface G, the frame body sway restriction means A restricts the swinging of the frame bodies 7, 8, on whose front and rear ends the second running wheels 12 are disposed, about the left and right support shafts 9, 10. Therefore, when the second running wheel 12 is raised above the running surface G, the frame bodies 7, 8 do not swing and the minimum ground clearance (the vertical distance from the horizontal ground surface to the lowest point of the vehicle body) does not decrease, so the required minimum ground clearance can be maintained.

[0077] When the unmanned guided vehicle 1 is a low-floor type with a low overall height as shown in Figures 2 and 3, the lifting stroke cannot be increased when the running wheel switching mechanism C brings one of the first running wheel 11 and the second running wheel 12 into contact with the running surface G and keeps the other one raised.

[0078] In this embodiment, when the frame body rocking restriction means A is in an operational state shown in FIG. 9, an imaginary plane K that abuts from below on the second traveling wheels 12 arranged at the front and rear ends of the frame bodies 7, 8 becomes substantially horizontal.

[0079] Therefore, when an automated guided vehicle 1 travels both within a shelf system having item storage space and on the ground outside the shelf system, and within the shelf system, it slips under the item support member on which the item is placed to transport the item in or out, the low-floor automated guided vehicle 1 increases the item storage efficiency, while the required minimum ground clearance can be maintained even though the automated guided vehicle 1 is of the low-floor type.

[0080] The above description of the embodiments is given by way of example only and is not intended to be limiting, and various improvements and modifications can be made without departing from the scope of the present invention. [Explanation of symbols]

[0081] 1 Automated guided vehicle 2 Vehicle body 3 Main frame 4,5 Sub-frame 6 Lifting table 7,8 Frame body 9, 10 Left and right support shaft 11 First running wheel 12 second running wheel 13,14 driving wheel 13A, 14A Axle 15, 16 Driven wheel (swivel wheel) 15A,16A Axle 17 Front end support 17A Top surface 18 Rear end support 18A Top 19,20 Support bracket 19A, 20A Horizontal plate 21A, 22A Bolt 21B, 22B Nut 23 Roller 24 Cam follower 25 Hanger 26A, 26B Spur gear 27A, 27B Bevel gear 28 Shaft 29A, 29B Sprocket 30 Chain 31 Tension roller 32A, 32B Sprockets 33 Chain 34A, 34B idler sprockets 35A, 35B sprockets 36 Chain 37A, 37B Idler sprocket 38A, 38B Spur gear 39A, 39B Sprocket 40 Chain 41A, 41B Idler sprocket 42A, 42B Sprockets 43 Chain 44A, 44B Idler sprocket A Frame body swing restriction means B Rear C Traveling wheel switching mechanism D1, D2, D3, D4 Switching cam E1, E2, E3, E4 Lifting cam F Front G Running surface H Horizontal guide roller I,J Cover K Virtual plane L Left M1, M2 Travel drive device M3 Traveling wheel switching mechanism drive unit M4 Lifting drive unit N Base P1, P2 Positioning part R Right side S1 1st shaft section S2 2nd shaft part S3A 3rd left shaft part S3B 3rd right shaft section S4 4th shaft section T1,T2 tip

Claims

1. An automated guided vehicle including a plurality of first running wheels whose axles are oriented in a front-rear direction, a plurality of second running wheels whose axles are oriented in a left-right direction, and a running wheel switching mechanism that brings one of the first running wheels and the second running wheels into contact with a running surface and keeps the other one off the ground, a pair of left and right frame bodies extending in the front-rear direction, the frame bodies being supported at a middle position by left-right support shafts and swinging about the left-right support shafts; A part of the second traveling wheel is disposed at a front end portion and a rear end portion of the frame body, a frame body swing restriction means for restricting swinging of the frame body about the left-right support shaft when the first running wheel is brought into contact with the running surface by the running wheel switching mechanism and the second running wheel is raised off the running surface, Automated guided vehicle.

2. The frame body rocking restriction means is In conjunction with the lifting and lowering operation of the second running wheel by the running wheel switching mechanism, The swing of the frame body is restricted when the second traveling wheel is raised, releasing the restriction on the swing of the frame body when the second traveling wheel is lowered.

2. The automated guided vehicle according to claim 1.

3. the frame body rocking restriction means is a positioning portion provided on a base body side supporting the first running wheel and abutting against the frame body from above, The positioning portion is When the second running wheels arranged at the front end and the rear end of the frame body are lifted off the running surface and the frame body is tilted forward around the left-right support shaft, the second running wheels are arranged behind the left-right support shaft, When the frame body is tilted backward about the left-right support shaft when the second running wheels arranged at the front end and the rear end of the frame body are lifted off the running surface, the second running wheels are arranged in front of the left-right support shaft.

3. The automated guided vehicle according to claim 2.

4. the frame body rocking restriction means is a positioning portion provided on a base body side supporting the first running wheel and abutting against the frame body from above, The positioning portions are disposed in front of and behind the left-right support shaft.

3. The automated guided vehicle according to claim 2.

5. The vehicle travels both within a shelf system having an item storage space and on the ground outside the shelf system; In the shelf system, the robot crawls under an article support member on which an article is placed to carry the article in or out, When the swing of the frame body is restricted by the frame body swing restriction means, an imaginary plane that contacts from below the second running wheels disposed at the front end and the rear end of the frame body becomes substantially horizontal. An automated guided vehicle according to any one of claims 1 to 4.

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