Unmanned transport vehicle

Abstract

An unmanned transport vehicle according to an embodiment comprises: a body which supports a load and is configured by connecting a plurality of frames; a pair of driving wheels provided on the front part and the rear part under the body, respectively; one pair of casters provided at each of the front part and the rear part under the body, the casters being positioned on opposite sides of each of the pair of driving wheels, respectively; and an elevation driving part for adjusting pressure with which the driving wheels press the ground in response to the weight of the load loaded on the body, wherein the driving wheel and the caster are provided in a state of being in contact with the ground, the caster is provided to be maintained at a predetermined height, and the driving wheels are provided to have a variable height.

Description

unmanned transport vehicles

[0001] The present invention relates to an unmanned transport vehicle, and more particularly, to an unmanned transport vehicle capable of transporting a load to another location unmanned.

[0002] With the rapid development of the logistics industry, various logistics systems are being developed. For example, unmanned transport vehicles are being used to increase logistics management efficiency and boost productivity.

[0003] Such unmanned transport vehicles move by motor drive while loaded with cargo, and transport the cargo to a set location.

[0004] Prior art related to unmanned transport vehicles is disclosed in Korean Patent No. 10-1772631 and Korean Patent No. 10-1642728.

[0005] The above-mentioned unmanned transport vehicle is provided with a loading plate on the upper part, and when the load to be transported is loaded on the upper part of the loading plate, the driving wheels are driven to drive the vehicle. The driving wheels are provided in pairs at the front and rear of the unmanned transport vehicle, and casters are provided as driven wheels on both sides of the driving wheels.

[0006] In addition, the driving wheels provided on the above-mentioned unmanned transport vehicle have a spring structure that applies a suspension load to maintain friction with the ground even when the floor flatness is poor.

[0007] In the case of conventional high-load unmanned transport vehicles, there was a problem in that the ground on which the driving wheels repeatedly drove was dug up and damaged because the suspension load shared by the driving wheels was set high compared to the driven wheels in order to maximize the friction of the driving wheels.

[0008] The present invention has been devised to solve the above-described problems, and its purpose is to provide an unmanned transport vehicle that can prevent damage to the ground as much as possible by distributing the load received by the driving wheels and casters as much as possible both when the vehicle is empty and when the vehicle is fully loaded.

[0009] In order to achieve the above-described purpose, the present invention provides an unmanned transport vehicle, comprising: a main body that supports a load and is formed by connecting a plurality of frames; a pair of driving wheels provided at a front portion and a rear portion of the lower portion of the main body, respectively; casters provided at both sides of each of the pair of driving wheels, one pair each at the front portion and the rear portion of the lower portion of the main body; and an elevation driving unit that adjusts the pressure with which the driving wheels press on the ground in response to the weight of the load loaded on the main body, wherein the driving wheels and the casters are provided in a state of contacting the ground, and the casters are provided so as to be maintained at a constant height, and the driving wheels are provided so as to be able to change in height.

[0010] The above body includes a fixed frame, a movable frame that can be moved up and down by rotating around a pivot shaft connected to the fixed frame, and a support plate that is connected to the movable frame and supports the driving wheel so that the driving wheel can be moved up and down in conjunction with the movement of the movable frame. The lifting drive unit may include a pressing member that is moved up and down by receiving power from a motor, and a pressing amount adjusting means that is provided between the pressing member and the support plate and adjusts the downward pressure applied by the pressing member to correspond to the weight of the load and transmits the pressure to the support plate.

[0011] The above-mentioned pressure amount control means is composed of a plurality of springs whose upper and lower ends are supported by the lower surface of the pressure member and the upper surface of the support plate, and the plurality of springs are provided in a symmetrical structure on both sides of the pressure member based on the longitudinal middle portion of the pressure member, and may be provided such that the upper and lower lengths of the springs gradually become shorter and the elastic modulus of the springs gradually increases as they go from the longitudinal both sides of the pressure member to the longitudinal middle portion of the pressure member.

[0012] The above-mentioned lifting / lowering driving unit may include a screw shaft that receives power from the motor and rotates in place, and is vertically provided through the pressure member and the support plate, and a nut member that is screw-connected to the screw shaft and is lifted and lowered in conjunction with the rotation of the screw shaft and is connected to the pressure member.

[0013] The above movable frame includes a first movable frame and a second movable frame that share the pivot axis and are provided on both sides of the pivot axis and can rotate up and down about the pivot axis, and the pair of driving wheels can be provided on the lower part of the first movable frame and the lower part of the second movable frame at a position spaced apart from the pivot axis.

[0014] The above-mentioned pressure amount control means is formed of a spring whose upper and lower ends are supported by the lower surface of the pressure member and the upper surface of the support plate, and the movable frame includes a first movable frame and a second movable frame that share the pivot axis and are provided on both sides of the pivot axis and can rotate up and down around the pivot axis, and the pressure member and the spring may receive driving force from one motor to simultaneously pressurize the support plate of the first movable frame and the support plate of the second movable frame.

[0015] A first lifting guide part that supports the movable frame to move in a vertical direction is included, wherein the first lifting guide part includes a first moving block having one side in contact with the side surface of the movable frame and the other side in a first inclined plane inclined in one direction with respect to the vertical plane, and a first fixed block having one side joined to the fixed frame and the other side in which a second inclined plane is formed that is in contact with the first inclined plane of the first moving block, and a first long hole that penetrates in the front-back direction and has a length in the up-down direction is formed in the first moving block, and the first moving block can be fixed in position by a first fastening member that penetrates the first long hole and is fastened to the first fixed block while one side of the first moving block is in contact with the side surface of the movable frame by adjusting the height.

[0016] A second lifting guide part that supports the pressing member to move in a vertical direction is included, wherein the second lifting guide part includes a second moving block fastened to the movable frame, a third moving block having one side joined to one side of the second moving block and a third inclined surface formed on the other side that is inclined to one side based on the left-right direction of the movable frame, and a second fixed block having one side joined to a side of the pressing member and a fourth inclined surface formed on the other side that contacts the third inclined surface and is fastened to the pressing member, and a second long hole is formed that penetrates in the vertical direction and has a length in the left-right direction, and the second moving block and the third moving block can be fixed in position by a second fastening member that penetrates the second long hole and is fastened to the movable frame in a state where the third inclined surface contacts the fourth inclined surface by adjusting the position of the movement in the left-right direction.

[0017] The driving force of the motor is transmitted to the screw shaft via a plurality of connecting shafts interconnected by a coupler, and a key groove formed on the outer surface of a connection portion between the plurality of connecting shafts and a key groove formed on the inner surface of the coupler are aligned in the same phase with each other, and a key is inserted into the key groove of the connecting shaft and the key groove of the coupler to couple the plurality of connecting shafts and the coupler, and a plurality of key grooves may be formed at positions spaced apart from each other along the circumferential direction on the outer surface of at least one of the plurality of connecting shafts.

[0018] The above driving wheel and the caster are provided in a state of contacting the ground, and the caster is supported by the fixed frame and maintained at a constant height, and the driving wheel is made of a compressible material and is supported by the movable frame and the pressure amount adjusting means so that the height can be changed.

[0019] According to the unmanned transport vehicle according to the present invention, by adjusting the suspension load of the driving wheel in response to the weight of the load, the load can be distributed to the caster as much as possible, thereby preventing damage to the ground in contact with the driving wheel even when the weight of the load is heavy.

[0020] In addition, it is possible to precisely adjust the suspension load of the driving wheel by providing a pressure control means.

[0021] In addition, by using one motor, the first movable frame and the second movable frame can be linked to move up and down, so that the suspension load of a pair of driving wheels provided at the front and rear can be adjusted to a constant height at the same time.

[0022] In addition, by providing a first lifting guide section and a second lifting guide section so that the movable frame and the pressure member are raised and lowered in a vertical direction, the suspension load of the driving wheel can be accurately adjusted without error.

[0023] In addition, by forming multiple keyways in the connection portions between multiple connecting shafts that transmit the power of the motor, the keyways formed in the multiple connecting shafts and the keyways formed in the coupler can be easily adjusted to have the same phase, so that the fastening work between the connecting shafts and the coupler can be easily performed.

[0024] In addition, since a pressure control means is provided on the upper part of the driving wheel and the caster is supported by a fixed frame so that the height is maintained constant, when moving the load loaded on the unmanned transport vehicle to the unloading location, the height of the bottom of the load loaded on the unmanned transport vehicle and the height of the unloading location (pass line) can be made to match, so that the unloading work of the load can be performed smoothly.

[0025] In addition, since the two driving wheels are supported by a pressure control means, they are always kept in contact with the ground, and since the four casters are always positioned at the same height, even if the ground is uneven, at least three casters and two driving wheels are always kept in contact with the ground, so that the load of the load can be distributed to the casters and driving wheels as much as possible, thereby improving the driving stability of the unmanned transport vehicle.

[0026] Figure 1 is a perspective view of an unmanned transport vehicle according to the present invention;

[0027] Figure 2 is a plan view of an unmanned transport vehicle according to the present invention;

[0028] Figure 3 is a right side view of an unmanned transport vehicle according to the present invention;

[0029] Figure 4 is a perspective view showing the connection structure of the first movable frame and the second movable frame provided in the unmanned transport vehicle according to the present invention.

[0030] Figure 5 is a front view showing a structure in which the first movable frame and the second movable frame provided in the unmanned transport vehicle according to the present invention can rotate up and down around a pivot axis.

[0031] FIG. 6 is a drawing for explaining the position at which the pressure member is supported by the first to third springs according to the difference in weight of the load loaded on the unmanned transport vehicle according to the present invention.

[0032] Figure 7 is a drawing for explaining the driving structure for forward / backward movement and steering of the driving wheels of the unmanned transport vehicle according to the present invention.

[0033] Figure 8 is a perspective view showing the first and second lifting guide sections of the unmanned transport vehicle according to the present invention.

[0034] Fig. 9 is a right side view for explaining the operation of the first lifting guide part shown in Fig. 8.

[0035] Fig. 10 is a plan view for explaining the operation of the second lifting guide part shown in Fig. 8.

[0036] Figure 11 is a drawing showing a coupler coupled to a connecting portion between connecting shafts of reducers provided in an unmanned transport vehicle according to the present invention.

[0037] Figure 12 is an exploded perspective view for explaining a structure in which a coupler is connected by a key to a connecting portion between connecting shafts of reducers provided in an unmanned transport vehicle according to the present invention.

[0038] Figure 13 is a cross-sectional view showing a coupling structure between a first reduction gear connecting shaft and one side of a coupler and a coupling structure between a second reduction gear connecting shaft and the other side of a coupler provided in an unmanned transport vehicle according to the present invention.

[0039] ** Explanation of symbols **

[0040] 1: Unmanned transport vehicle 10: Drive wheels

[0041] 20: Caster 100: Body

[0042] 110: Fixed frame 111: First fixed frame

[0043] 112: Second fixed frame 113: Third fixed frame

[0044] 114: 4th fixed frame 115: 5th fixed frame

[0045] 120: Movable frame 120-1: First movable frame

[0046] 120-2: Second movable frame 121: One side of the movable frame

[0047] 122: Other side of the movable frame 123: Connection part of the movable frame

[0048] 130: Upper frame 130-1: First upper frame

[0049] 130-2: Second upper frame 140: Support plate

[0050] 140-1: First support plate 140-2: Second support plate

[0051] 150: Pivot shaft 200: Lifting drive unit

[0052] 210: First motor (motor) 211: First motor shaft

[0053] 220: First reduction gear 221: First connecting shaft

[0054] 221a-1, 220a-2, 221a-3: 1st keyway 221b: 1st key

[0055] 222: Third connecting shaft 230: Second reducer

[0056] 231: Second connecting shaft 231a: Second keyway

[0057] 231b: Second key 232: First screw shaft

[0058] 240: Third reduction gear 241: Fourth connecting shaft

[0059] 242: Second screw shaft 250: Coupler

[0060] 250-1: 1st coupler 250-2: 2nd coupler

[0061] 250a: Coupler keyway 260: Nut member

[0062] 270: Pressing member 280: Pressing amount control means

[0063] 281: First spring 281a: First spring support rod

[0064] 282: Second spring 282a: Second spring support rod

[0065] 283: Third spring 283a: Third spring support rod

[0066] 300: Drive unit 310: Second motor

[0067] 320: Brake 330: Third motor

[0068] 331: Pinion gear 340: Fixed gear

[0069] 350: First support member 360: Second support member

[0070] 400: First lifting guide section 410: First moving block

[0071] 411: First section 412: First slope

[0072] 420: First fixed block 421: First part

[0073] 422: Part 2 423: Slope 2

[0074] 500: Second lifting guide section 510: Second moving block

[0075] 511: 2nd chapter 520: 3rd movement block

[0076] 521: 3rd slope 530: 2nd fixed block

[0077] 531: 4th slope G: Ground

[0078] L1: Length of the first spring L2: Length of the second spring

[0079] L3: Length of the third spring

[0080] Hereinafter, the configuration and operation of a preferred embodiment of the present invention will be described in detail with reference to the attached drawings. Hereinafter, in referring to directions in this specification, the XX' direction shown in FIG. 1 is referred to as the front-back direction, the YY' direction is referred to as the left-right direction, the Z-Z' direction is referred to as the up-down direction, the X direction is referred to as the front, and the X' direction is referred to as the rear.

[0081] Referring to FIGS. 1 to 3, an unmanned transport vehicle (1) of the present invention includes a main body (100) that supports a load and is formed by connecting a plurality of frames (110, 120), a pair of driving wheels (10) provided at the front and rear portions of the lower portion of the main body (100), a pair of casters (20) provided at the front and rear portions of the lower portion of the main body (100) and positioned on both sides of each of the pair of driving wheels (10), and a lifting and lowering driving unit (200) that adjusts the height of the driving wheels (10) so that the pressure with which the driving wheels (10) press against the ground (G) is adjusted in response to the weight of the load loaded on the main body (100).

[0082] The above main body (100) includes a fixed frame (110) and a movable frame (120).

[0083] The above fixed frame (110) includes a first fixed frame (111) and a second fixed frame (112) provided on both left and right sides in the front and rear directions, a third fixed frame (113) having both ends connected to the front ends of the first fixed frame (111) and the second fixed frame (112), a fourth fixed frame (114) having both ends connected to the rear ends of the first fixed frame (111) and the second fixed frame (112), and a fifth fixed frame (115) having both ends connected to the middle portions of the first fixed frame (111) and the second fixed frame (112) and supporting the first drive motor (210) and the first reducer (220).

[0084] A pair of casters (20) are provided on the lower sides of the left and right sides of the third fixed frame (113) and on the lower sides of the left and right sides of the fourth fixed frame (114). That is, the casters (20) are provided on the lower sides of the front and rear sides of the fixed frame (110).

[0085] Referring to FIGS. 4 and 5, the movable frame (120) is provided so as to be rotatable around a pivot axis (150) provided in the left-right direction and connected at both ends to the front-rear middle portions of the first fixed frame (111) and the second fixed frame (112), and is composed of a first movable frame (120-1) and a second movable frame (120-2) that share the pivot axis (150) and are provided on both sides thereof.

[0086] The pivot shaft (150) passes through the rear end of the first movable frame (120-1) and the front end of the second movable frame (120-2) in the left and right directions, and both ends of the pivot shaft (150) are fixed and supported by the first fixed frame (111) and the second fixed frame (112), respectively.

[0087] The above pair of driving wheels (10) are provided at the lower part of the first movable frame (120-1) and the lower part of the second movable frame (120-2) at a position spaced apart from the pivot shaft (150).

[0088] The first movable frame (120-1) and the second movable frame (120-2) receive driving force from one motor (210, first motor) and can rotate in the up-and-down direction in conjunction with each other around the pivot shaft (150).

[0089] A support plate (140) that supports a driving wheel (10) is coupled to the above movable frame (120). The support plate (140) includes a first support plate (140-1) that is coupled to the first movable frame (120-1) and supports a driving wheel (10) provided at the front, and a second support plate (140-2) that is coupled to the second movable frame (120-2) and supports a driving wheel (10) provided at the rear.

[0090] Referring to FIG. 5, when the first movable frame (120-1) and the second movable frame (120-2) are rotated about the pivot axis (150) and moved in the up-and-down direction, a pair of driving wheels (10) provided at the front and rear also move in the up-and-down direction in conjunction therewith.

[0091] An upper frame (130; 130-1, 130-2) is provided on the front and rear ends of the fixed frame (110). The upper frame (130) includes a first upper frame (130-1) provided at the front to support a second reducer (230), and a second upper frame (130-2) provided at the rear to support a third reducer (240).

[0092] A loading plate (not shown) for loading a load (not shown) can be mounted on the upper part of the upper frame (130; 130-1, 130-2).

[0093] The above-described elevator drive unit (200) includes a first motor (210) as a driving source, a first reducer (220) connected to a first motor shaft (211) of the first motor (210), a second reducer (230) connected to a first connecting shaft (221) and a first coupler (250-1) and a second connecting shaft (231) on the front side of the first reducer (220), and a third reducer (240) connected to a third connecting shaft (222) and a second coupler (250-2) and a fourth connecting shaft (241) on the rear side of the first reducer (220).

[0094] A first screw shaft (232; FIG. 3) is vertically connected to the lower portion of the second reducer (230), and a second screw shaft (242; FIG. 12) is vertically connected to the lower portion of the third reducer (240). The configuration of the elevating drive unit (200) connected to the lower portion of the second reducer (230) is identical to the configuration of the elevating drive unit (200) connected to the lower portion of the third reducer (240), and therefore, the configuration of the elevating drive unit (200) connected to the lower portion of the second reducer (230) will be described below.

[0095] The first screw shaft (232) is provided with a male screw portion formed on its outer surface and rotates in place by receiving power from a first motor (210). A nut member (260) having a female screw portion formed on its inner surface is screw-connected to the outer surface of the first screw shaft (232), and a pressure member (270) is coupled to the nut member (260). The first screw shaft (232) is provided vertically so as to penetrate the pressure member (270) and the first support plate (140-1). When the first screw shaft (232) rotates by receiving power from the first motor (210), the nut member (260) and the pressure member (270) move up and down as one unit.

[0096] Referring to FIGS. 4 and 6, the lifting drive unit (200) includes a pressure amount control means (280) that is provided between the pressure member (270) and the first support plate (140-1) and controls the downward pressure applied by the pressure member (270) to correspond to the weight of the load and transmits the pressure to the first support plate (140-1).

[0097] The above-mentioned pressure control means (280) is composed of a plurality of springs (281, 282, 283) whose upper and lower ends are supported by the lower surface of the pressure member (270) and the upper surface of the first support plate (140-1).

[0098] The above plurality of springs (281, 282, 283) are provided in a symmetrical structure on both sides of the pressure member (270) based on the longitudinal middle portion of the pressure member (270).

[0099] The vertical lengths of the springs (281, 282, 283) are gradually shortened from the longitudinal sides of the pressure member (270) to the longitudinal middle of the pressure member (270), and the elastic modulus of the springs (281, 282, 283) is gradually increased.

[0100] In one embodiment, the plurality of springs (281, 282, 283) may be configured with a pair of first springs (281) provided on both longitudinal ends of the pressure member (270) and having the longest length (L1) and a relatively small elastic coefficient, a pair of second springs (282) provided on the longitudinal middle portion of the pressure member (270) and having a shorter length (L2) than the first spring (281) and a larger elastic coefficient than the first spring (281), and two pairs of third springs (283) provided on the longitudinal inner ends of the pressure member (270) and having a shorter length (L3) than the second spring (282) and a larger elastic coefficient than the second spring (282).

[0101] By configuring the lengths and elastic coefficients of the plurality of springs (281, 282, 283) in this way, when the weight of the load is relatively light, the rotation amount of the first motor (210) is adjusted to a rotation amount set to correspond to the weight of the light load, thereby moving the pressure member (270) to a relatively raised position, and when the weight of the load is relatively heavy, the rotation amount of the first motor (210) is adjusted to a rotation amount set to correspond to the weight of the heavy load, thereby moving the pressure member (270) to a relatively lowered position.

[0102] Accordingly, when the pressure member (270) is moved upward and then gradually moved downward, the bottom surface of the pressure member (270) first comes into contact with the upper end of the first spring (281), and then the upper ends of the second spring (282) and the third spring (283) come into contact sequentially, and as the first to third springs (281, 282, 283) are compressed, the compressive force is transmitted to the first support plate (140-1) located below, and the first movable frame (120-1) coupled to the first support plate (140-1) rotates about the pivot shaft (150) by the force acting on the first support plate (140-1), and at the same time, the driving wheel (10) also moves up and down.

[0103] In this way, by configuring the plurality of springs (281, 282, 283) with different lengths and elastic moduli, the pressure member (270) is moved up and down with different heights according to the weight of the load, so that the driving wheel (10) can have an appropriate frictional force with the ground (G), while the height of the driving wheel (10) can be precisely adjusted to an optimal height according to the weight of the load within a range where excessive pressure is not applied to the ground (G).

[0104] Referring to FIGS. 6 and 7, the unmanned transport vehicle (1) includes a driving drive unit (300) for driving the driving wheel (10) forward and backward and for steering.

[0105] The above driving drive unit (300) includes a second motor (310) that provides power to drive the driving wheel (10) forward and backward, a brake (320) that stops the driving wheel (10) when the power supply is cut off, and a third motor (330) that provides power to steer the driving wheel (10). A fixed gear (240) is coupled to the bottom surface of the first support plate (140-1), a first support member (350) is coupled to the lower portion of the fixed gear (240), and a second support member (360) that supports the second motor (310), the driving wheel (10), and the brake (320) is coupled to the lower portion of the first support member (350). A pinion gear (331) is coupled to the shaft of the third motor (330), and the pinion gear (331) is gear-coupled with a fixed gear (340).

[0106] The above fixed gear (240) is fixedly coupled to the bottom surface of the first support plate (140-1) so as not to rotate, and the rotational axis (not shown) of the first support member (350) is connected to the fixed gear (340) so as to be able to rotate relative to it, and the third motor (330) is coupled to the first support member (350). Therefore, when the pinion gear (331) rotates by the driving of the third motor (330), the pinion gear (331) moves along the circumference of the fixed gear (340) to which it is gear-coupled, and in conjunction with this, the third motor (330), the first support member (350), the second support member (360), the second motor (310), the brake (320), and the driving wheel (10) all rotate together. Therefore, the steering operation of the driving wheel (10) is performed according to the rotation direction and rotation amount of the third motor (330).

[0107] Referring to FIGS. 8 to 10, the unmanned transport vehicle (1) is configured to accurately adjust the height at which the driving wheel (10) is raised and lowered, and includes a first lifting guide part (400) that supports the movable frame (120) to move vertically, and a second lifting guide part (500) that supports the pressure member (270) to move vertically.

[0108] Referring to FIGS. 8 and 9, the first lifting guide part (400) includes a first movable block (410) having one side in contact with the side of the movable frame (120) and the other side formed with a first inclined surface (412) inclined to one side with respect to a vertical plane, and a first fixed block (420) having one side joined to the fixed frame (110) and the other side formed with a second inclined surface (423) that contacts the first inclined surface (412) of the first movable block (410).

[0109] The first fixed block (420) may be composed of a first part (421) that contacts one side of the first movable block (410) and has the second inclined surface (423) formed thereon, and a second part (422) that extends to one side from the rear end of the first part (421) and contacts the rear end of the first movable block (410).

[0110] The first movable block (410) is formed with a first long hole (411) that penetrates in the front-back direction and has a length in the up-down direction, and the first movable block (410) can be adjusted in height so that one side of the first movable block (410) is in contact with the side surface of the movable frame (120), and the first fastening member (430) that penetrates the first long hole (411) and is fastened to the second part (422) of the first fixed block (420) can be fixed in position. The arrows illustrated in FIG. 9 indicate a state in which the first movable block (410) is in close contact with the first fixed frame (111) and the second fixed frame (112) as the first movable block (410) moves downward. According to the configuration of the first lifting guide part (400) as described above, the first moving block (410) and the first fixed frame (111) and the second fixed frame (112) are in close contact with each other without any play, so that the movable frame (120) can be accurately moved up and down in the vertical direction, and the driving wheel (10) can be accurately adjusted to the set height.

[0111] Referring to FIGS. 8 and 10, the second lifting guide part (500) includes a second moving block (510) that is fastened to a connecting part (123) that connects one side (121) and the other side (122) of the movable frame (120), a third moving block (520) that is fastened to one side of the second moving block (510) on one side and has a third inclined surface (521) formed on the other side that is inclined to one side based on the left-right direction of the movable frame (120), and a second fixed block (530) that is fastened to the side of the pressing member (270) on one side and has a fourth inclined surface (531) formed on the other side that comes into contact with the third inclined surface (521) and is fastened to the pressing member (270).

[0112] The second movable block (510) is formed with a second long hole (511) that penetrates in the vertical direction and has a length in the left-right direction, and the second movable block (510) and the third movable block (520) can be fixed in position by a second fastening member (540) that penetrates the second long hole (511) and is fastened to the movable frame (120) while the left-right movement position of the third inclined surface (521) is in contact with the fourth inclined surface (531).

[0113] The arrows shown in Fig. 10 indicate a state in which the third moving block (520) is in close contact with the second fixed block (530) due to the movement of the second moving block (510) and the third moving block (520).

[0114] In this embodiment, the second moving block (510) and the third moving block (520) are illustrated as being formed as separate components and interconnected, but the second moving block (510) and the third moving block (520) may also be formed as an integrated structure.

[0115] According to the configuration of the second lifting guide part (500) as described above, the pressure member (270) can be accurately moved up and down in the vertical direction by ensuring that the third moving block (520) and the second fixed block (530) are in close contact without any play, so that the driving wheel (10) can be accurately adjusted to the set height.

[0116] Referring to FIGS. 11 to 13, the driving force of the first motor (210) is transmitted to the screw shaft (232, 242) via a plurality of connecting shafts (221, 231, 222, 241) interconnected by couplers (250-1, 250-2).

[0117] In a state where the key grooves (221a-1, 221a-2, 221a-3, 231a) formed on the outer surface of the connection portion between the plurality of connecting shafts (221, 231, 222, 241) and the key groove (250a) formed on the inner surface of the coupler are aligned in the same phase, a key (221b, 231b) is inserted into the key grooves (221a-1, 221a-2, 221a-3, 231a) of the connecting shafts (221, 231, 222, 241) and the key groove (250a) of the coupler (250-1, 250-2), thereby connecting the plurality of connecting shafts (221, 231, 222, 241) and the coupler (250-1, 250-2).

[0118] On the outer surface of at least one of the plurality of connecting shafts (221, 231, 222, 241), a plurality of key grooves (221a-1, 221a-2, 221a-3) are formed at spaced locations along the circumferential direction. In this embodiment, a case in which three key grooves (221a-1, 221a-2, 221a-3) are formed along the circumferential direction on the outer surface of the connecting portion of the first connecting shaft (221) is exemplified, and a plurality of key grooves may be formed in a similar manner on the outer surface of the connecting portion of the third connecting shaft (222). In addition, a case in which one key groove (231a) is formed on the second connecting shaft (231) and the fourth connecting shaft (241), and four key grooves (250a) are formed on the coupler (250-1, 250-2) is exemplified.

[0119] According to this configuration, the keyways between the plurality of connecting shafts (221, 231, 222, 241) can be easily adjusted to have the same phase, so that the phase adjustment of the keyways between the plurality of connecting shafts (221, 231, 222, 241) and the coupler (250-1, 250-2) is simplified, and thus the fastening work can be easily performed.

[0120] Meanwhile, the driving wheel (10) and caster (20) provided in the unmanned transport vehicle (1) of the present invention are provided in a state of contacting the ground (G), and the caster (20) is supported by a fixed frame (110) and maintained at a constant height, and the driving wheel (10) is made of a material that can be compressed and deformed, and is supported by the movable frame (120) and the pressure amount adjusting means (280) and configured so that the height can be changed.

[0121] In this way, the pressure control means (280) is provided on the upper part of the driving wheel (10), and the caster (20) is supported by the fixed frame (110) so that the height is maintained constant, so that when the load loaded on the unmanned transport vehicle (1) is moved to the unloading location, the height of the bottom of the load loaded on the unmanned transport vehicle (1) and the height of the unloading location (pass line) can be made to match, so that the unloading work of the load can be performed smoothly.

[0122] In addition, since the two driving wheels (10) are supported by the pressure control means (280), they are always kept in contact with the ground, and since the four casters (20) are always positioned at the same height, even if the ground (G) is uneven, at least three casters (20) and two driving wheels (10) are always kept in contact with the ground, so that the load of the load can be distributed to the casters (20) and driving wheels (10) as much as possible, thereby improving the driving stability of the unmanned transport vehicle (1).

[0123] As described above, the present invention is not limited to the above-described embodiments, and obvious modifications can be made by a person having ordinary skill in the art to which the invention pertains without departing from the technical spirit of the present invention as claimed in the claims, and such modifications fall within the scope of the present invention.

Claims

1. A main body formed by connecting multiple frames and supporting a load; A pair of driving wheels provided at the front and rear portions of the lower portion of the main body, respectively; Casters positioned on both sides of each of the above pair of driving wheels, one pair each provided at the front and rear portions of the lower portion of the main body; and An elevator drive unit that adjusts the pressure with which the driving wheel presses the ground in response to the weight of the load loaded on the main body; Including, The above driving wheel and the above caster are provided in contact with the ground, The above caster is provided to be maintained at a constant height, An unmanned transport vehicle characterized in that the above driving wheels are equipped to allow for height adjustment.

2. In paragraph 1, The above body includes a fixed frame, a movable frame that can be moved up and down by rotating around a pivot axis connected to the fixed frame, and a support plate that is connected to the movable frame and supports the driving wheel so that the driving wheel can be moved up and down in conjunction with the movement of the movable frame. The above-mentioned lifting and lowering driving unit is an unmanned transport vehicle including a pressing member that is moved up and down by receiving power from a motor, and a pressing amount control means that is provided between the pressing member and the support plate and controls the downward pressure applied by the pressing member to correspond to the weight of the load and transmits the pressure to the support plate.

3. In paragraph 2, The above-mentioned pressure control means is composed of a plurality of springs whose upper and lower ends are supported by the lower surface of the pressure member and the upper surface of the support plate, An unmanned guided vehicle characterized in that the plurality of springs are provided in a symmetrical structure on both sides of the pressing member based on the longitudinal middle portion of the pressing member, and the vertical length of the springs gradually becomes shorter and the elastic coefficient of the springs gradually increases as they go from the longitudinal middle portion of the pressing member to the longitudinal middle portion of the pressing member.

4. In paragraph 2, An unmanned transport vehicle characterized in that the above-mentioned lifting and lowering driving unit receives power from the motor, rotates in place, and includes a screw shaft provided vertically through the pressure member and the support plate, and a nut member that is screw-connected to the screw shaft and is lifted and lowered in conjunction with the rotation of the screw shaft and is connected to the pressure member.

5. In paragraph 2, The above movable frame includes a first movable frame and a second movable frame that share the pivot axis and are provided on both sides of the pivot axis and can rotate up and down about the pivot axis. An unmanned transport vehicle characterized in that the pair of driving wheels are provided on the lower part of the first movable frame and the lower part of the second movable frame at a position spaced apart from the pivot axis.

6. In paragraph 2, The above-mentioned pressure control means is composed of a spring whose upper and lower ends are supported by the lower surface of the pressure member and the upper surface of the support plate; The above movable frame includes a first movable frame and a second movable frame that share the pivot axis and are provided on both sides of the pivot axis and can rotate up and down about the pivot axis; An unmanned transport vehicle characterized in that the above-mentioned pressure member and spring receive driving force from one motor and simultaneously pressure the support plate of the first movable frame and the support plate of the second movable frame.

7. In paragraph 2, Including a first lifting guide part that supports the above movable frame to move in a vertical direction, The first lifting guide section includes a first movable block having one side in contact with the side of the movable frame and the other side formed as a first inclined surface inclined to one side with respect to a vertical plane, and a first fixed block having one side joined to the fixed frame and the other side formed as a second inclined surface that contacts the first inclined surface of the first movable block. An unmanned transport vehicle characterized in that a first long hole is formed through the first movable block in the front-back direction and has a length in the up-down direction, and the first movable block is fixed in position by a first fastening member that penetrates the first long hole and is fastened to the first fixed block while one side of the first movable block is in contact with the side surface of the movable frame, such that the first movable block is adjusted in height.

8. In paragraph 2, Including a second lifting guide part that supports the above-mentioned pressure member to move in a vertical direction, The second lifting guide section includes a second moving block fastened to the movable frame, a third moving block having one side joined to one side of the second moving block and a third inclined surface formed on the other side that is inclined to one side based on the left-right direction of the movable frame, and a second fixed block having one side joined to the side of the pressing member and a fourth inclined surface formed on the other side that contacts the third inclined surface and is coupled to the pressing member. An unmanned transport vehicle characterized in that a second long hole is formed in the second movable block and has a length in the left-right direction, and the second movable block and the third movable block are fixed in position by a second fastening member that passes through the second long hole and is fastened to the movable frame while the left-right movement position is adjusted so that the third inclined surface is in contact with the fourth inclined surface.

9. In paragraph 4, The driving force of the above motor is transmitted to the screw shaft through a plurality of connecting shafts interconnected by a coupler, The key groove formed on the outer surface of the connecting portion between the plurality of connecting shafts and the key groove formed on the inner surface of the coupler are aligned in the same phase, and a key is inserted into the key groove of the connecting shaft and the key groove of the coupler, so that the plurality of connecting shafts and the coupler are connected. An unmanned transport vehicle characterized in that a plurality of keyways are formed at positions spaced apart along the circumferential direction on the outer surface of at least one of the plurality of connecting axes.

Images