Overhead transporter

Abstract

The overhead transport vehicle (1) includes a first support portion (50), a second support portion (40), and a connecting rod mechanism (70). The first support portion (50) includes a first buffer portion (58) connected to a belt (9) on one side of the width direction of the main body when viewed from above. The second support portion (40) includes a second buffer portion (48) connected to the belt (9) on the other side of the width direction of the main body. The connecting rod mechanism (70) connects the first support portion (50) and the second support portion (40) so that a first distance in the vertical direction between the first support portion (50) and the base portion (10A) and a second distance between the second support portion (40) and the base portion (10A) are close to each other. The link mechanism (70) has at least one of a third buffer portion (71, 72, 75, 76) capable of enabling relative movement of the base portion (10A) relative to the first support portion (50) and the second support portion (40) in the travel direction and a fourth buffer portion (73, 77) capable of enabling relative movement in the width direction thereof.

Description

Technical Field

[0001] One aspect of the present invention relates to an overhead transport vehicle. Background Art

[0002] An aerial transport vehicle is known, comprising: a main body capable of traveling along a track; and a lifting portion having a gripping portion for gripping an article, and the lifting portion is raised and lowered by winding and releasing a plurality of suspension components relative to the main body. For example, Patent Document 1 discloses an aerial transport vehicle, wherein the lifting portion comprises: a base portion on which the gripping portion is mounted; and a plurality of buffer mechanisms having a support portion that supports the base portion from below in a manner that allows the base portion to move in the vertical direction via the buffer portion, and on which the suspension components are mounted, the plurality of buffer mechanisms being connected by a link mechanism. In this aerial transport vehicle, the link mechanism operates so that the distances between the support portions and the base portion of the plurality of buffer mechanisms connected to each other are close to each other, thereby reducing vibration transmitted to the article and suppressing shaking of the article.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: International Publication No. 2018 / 079146 Summary of the Invention

[0006] The above-mentioned conventional overhead transfer vehicles can reduce the vibration transmitted to the articles and suppress the shaking of the articles. However, with the diversification of the articles to be transferred, there is a demand for further reduction of vibration.

[0007] Therefore, an object of one aspect of the present invention is to provide an overhead transfer vehicle that can further reduce vibrations transmitted to articles and suppress shaking of articles.

[0008] The overhead transport vehicle of one aspect of the present invention comprises: a main body portion, which can travel along a track; and a lifting portion, which has a gripping portion for gripping an article and is lifted and lowered relative to the main body portion by a hanging member. In the overhead transport vehicle, the lifting portion comprises: a base portion on which the gripping portion is arranged; a first supporting portion, which has a first buffer portion for supporting the base portion from below in a vertical direction so that it can move in the vertical direction, and is connected to the hanging member on one side in a width direction orthogonal to the traveling direction of the main body portion when viewed from above in the vertical direction; a second supporting portion, which has a first buffer portion for supporting the base portion from below in a vertical direction so that it can move in the vertical direction A second buffer portion supported in an upwardly movable manner is connected to the hanging component on the other side in the width direction; and a link mechanism connecting the first support portion and the second support portion, and operating in a manner that a first distance in the vertical direction between the first support portion and the base portion and a second distance in the vertical direction between the second support portion and the base portion approach each other, the link mechanism having at least one of a third buffer portion and a fourth buffer portion, the third buffer portion being capable of realizing relative movement of the base portion relative to the first support portion and the second support portion in the traveling direction, and the fourth buffer portion being capable of realizing relative movement of the base portion relative to the first support portion and the second support portion in the width direction.

[0009] In this overhead transport vehicle, a linkage mechanism is provided that operates to bring a first vertical distance between the first support and the base closer to a second vertical distance between the second support and the base. This reduces left-right tilting of the lifting device and suppresses swaying of the items. Furthermore, buffers (first and second buffers) are provided on the first and second support portions to allow for vertical movement of the base relative to the first and second support portions. This reduces vertical vibration transmitted to the items via the lifting device. Furthermore, a buffer (at least one of the third and fourth buffers) is provided on the linkage mechanism to allow for horizontal movement of the base relative to the first and second support portions. This reduces horizontal vibration transmitted to the items via the lifting device. Consequently, vibration transmitted to the items can be further reduced and swaying of the items can be suppressed.

[0010] In the overhead transfer vehicle according to one aspect of the present invention, the link mechanism may include a third buffer portion. In this configuration, it is possible to reduce vibration in the front-rear direction transmitted to the article via the lifting portion.

[0011] In the overhead transfer vehicle according to one aspect of the present invention, the link mechanism may include both a third buffer and a fourth buffer. In this configuration, vibrations in both the front-rear direction and the left-right direction of the article transferred via the lifting unit can be reduced.

[0012] In one aspect of the overhead transfer vehicle of the present invention, the third or fourth buffer may include an elastic member. This can reduce horizontal vibration transmitted to the article via the lifting unit. This configuration effectively reduces vibration with a simple structure.

[0013] Effects of the Invention

[0014] According to one aspect of the present invention, it is possible to further reduce the vibration transmitted to the article and suppress the shaking of the article. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a front view showing an overhead transfer vehicle according to one embodiment.

[0016] Figure 2 This is a side view of the lifting device viewed from the front.

[0017] Figure 3 This is a perspective view of the lifting device viewed from obliquely above.

[0018] Figure 4 This is a perspective view of the lifting device with the base portion removed, as seen from obliquely above.

[0019] Figure 5 (A) and Figure 5 (B) is a perspective view showing a part of the second support portion and the connection mechanism in an enlarged manner.

[0020] Figure 6 (A) and Figure 6 (B) is a perspective view showing a part of the first support portion and the connection mechanism in an enlarged manner.

[0021] Figure 7 It is a perspective view showing a part of the second support portion and the link mechanism in an enlarged manner.

[0022] Figure 8 This is a perspective view of a lifting device according to a modified example, with the base portion removed, as seen from obliquely above. DETAILED DESCRIPTION

[0023] Hereinafter, one embodiment will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference numerals and repeated description will be omitted.

[0024] Figure 1 1 is a front view showing an overhead transfer vehicle according to one embodiment. Figure 2 This is a side view of the lifting device viewed from the front. Figure 1 and Figure 2 In the embodiment, the link mechanism 70 is omitted (see Figure 3 ) icon. Figure 1 The overhead transfer vehicle 1 shown travels along a travel track (track) 2 installed at a location higher than the floor, such as the ceiling of a clean room. The overhead transfer vehicle 1 transports articles such as FOUPs (Front Opening Unified Pods) 90 between, for example, storage equipment and a designated loading station. The FOUP 90 houses, for example, multiple semiconductor wafers. The FOUP 90 has a flange 98 that is held by the overhead transfer vehicle 1.

[0025] In the following description, for the sake of convenience, Figure 1 The left and right direction (X-axis direction) in is set as the driving direction of the overhead transfer vehicle 1 (hereinafter also referred to as the "front and back direction"). Figure 1 The vertical direction (Z-axis direction) in is set as the vertical direction of the overhead transfer vehicle 1 (hereinafter also referred to as the "vertical direction"). Figure 1 The depth direction (Y-axis direction) in FIG. 1 is defined as the width direction (hereinafter also referred to as the "left-right direction") of the overhead transfer vehicle 1. The X-axis, Y-axis, and Z-axis are orthogonal to each other.

[0026] like Figure 1 As shown, the overhead transport vehicle 1 includes a travel drive unit 3, a horizontal drive unit (main body) 5, a rotation drive unit (main body) 6, a lifting drive unit (main body) 7, a lifting device (lifting unit) 10, a holding device (gripping unit) 11, a first support unit 50 (see Figure 3 and Figure 4 )、Second support portion 40 (refer to Figure 3 and Figure 4 ) and the link mechanism 70 (refer to Figure 3 and Figure 4 ).

[0027] A pair of covers 8, 8 are provided on the overhead transfer vehicle 1 in the front-to-back direction to cover the horizontal drive unit 5, the rotation drive unit 6, the lifting drive unit 7, the lifting device 10, and the holding device 11. The covers 8, 8 form a space below the holding device 11 to accommodate FOUPs 90 when the lifting device 10 is raised to its upper end. A drop prevention mechanism 8A prevents FOUPs 90 held on the holding device 11 from falling when the lifting device 10 is raised to its upper end. A sway suppression mechanism 8B suppresses swaying of the FOUPs 90 held on the holding device 11 in the front-to-back direction (travel direction) and left-to-right direction of the overhead transfer vehicle 1 during travel.

[0028] The travel drive unit 3 moves the overhead transport vehicle 1 along the travel track 2. The travel drive unit 3 is arranged in the travel track 2. The travel drive unit 3 drives the rollers (not shown) that travel on the travel track 2. A horizontal drive unit 5 is provided at the lower part of the travel drive unit 3 with the aid of an axis 3A. The horizontal drive unit 5 moves the rotation drive unit 6, the lifting drive unit 7 and the lifting device 10 in a horizontal plane in a direction (left-right direction) perpendicular to the extension direction of the travel track 2. The rotation drive unit 6 rotates the lifting drive unit 7 and the lifting device 10 in a horizontal plane. The lifting drive unit 7 raises and lowers the lifting device 10 by winding and unwinding four belts (hanging components) 9. In addition, the belts 9 in the lifting drive unit 7 may also use appropriate hanging components such as metal wires and ropes.

[0029] like Figure 1 and Figure 2 As shown, the lifting device 10 in this embodiment is arranged to be raised and lowered by the lifting drive unit 7 and functions as a lifting platform in the overhead transport vehicle 1. The lifting device 10 includes a holding device 11 that grips a FOUP 90 and is raised and lowered relative to the horizontal drive unit 5, the rotation drive unit 6, and the lifting drive unit 7, which constitute the main body, using a belt 9. The holding device 11 holds the FOUP 90. The holding device 11 includes a pair of L-shaped arms 12, 12, handles 13, 13 fixed to each arm 12, 12, and an opening and closing mechanism 15 that opens and closes the pair of arms 12, 12.

[0030] A pair of arms 12, 12 are provided on an opening and closing mechanism 15. The opening and closing mechanism 15 moves the pair of arms 12, 12 in directions toward and away from each other. By the operation of the opening and closing mechanism 15, the pair of arms 12, 12 advance and retreat in the front-back direction. As a result, the pair of handles 13, 13 fixed to the arms 12, 12 are opened and closed. In this embodiment, when the pair of handles 13, 13 are in the open state, the height position of the holding device 11 (elevating device 10) is adjusted so that the holding surface of the handle 13 is at a position lower than the height of the lower surface of the flange 98. Furthermore, by closing the pair of handles 13, 13 in this state, the holding surface of the handles 13, 13 enters below the lower surface of the flange 98, and the lifting device 10 is raised in this state, so that the flange 98 is held (gripped) by the pair of handles 13, 13, and the FOUP 90 is supported.

[0031] The lifting device 10 includes a base portion 10A on which the holding device 11 is installed, a cover portion 10B covering the base portion 10A, a first support portion 50, and a second support portion 40. Figure 3 and Figure 4 As shown, the first support portion 50 and the second support portion 40 are mechanisms for connecting the belt 9 and the lifting device 10 , and are mechanisms for suppressing transmission of vibrations to the FOUP 90 when the travel drive unit 3 travels or when the lifting device 10 is raised or lowered.

[0032] The first support portion 50 includes an elastic member (first buffer portion) 58 that supports the base portion 10A from below so that it can move in the vertical direction. When viewed from above from the vertical direction, the first support portion 50 is positioned on one side in the width direction perpendicular to the travel direction of the overhead transfer vehicle 1. In this embodiment, the first support portion 50 is located on the right side of the lifting device 10 in the left-right direction. The first support portion 50 includes a connecting member 51, a swinging member 53, a first main body member 54, a second main body member 56, and a pair of elastic members 58, 58.

[0033] The connecting member 51 is attached to the belt 9. The swinging member 53 is connected to the connecting member 51. The swinging member 53 is connected to the connecting member 51 via a pin member 52 so that it can rotate in both directions. The first main body member 54 is a generally L-shaped member with a flat bottom. A portion of the first main body member 54 is connected to the swinging member 53. The bottom of the first main body member 54 is connected to the connecting portion 56B of the second main body member 56 by bolts or the like.

[0034] like Figure 3 、 Figure 4 、 Figure 6 (A) and Figure 6 As shown in (A), the second main body component 56 includes a main body portion 56A, a connecting portion 56B, a first side portion 56C, and a second side portion 56D. The main body portion 56A is a flat plate-shaped component that supports the elastic member 58 from below. One end of the connecting portion 56B is connected to the bottom of the first main body component 54, and the other end is connected to the main body portion 56A and the first side portion 56C. The first side portion 56C is vertically arranged from the main body portion 56A. The second side portion 56D is vertically arranged from the main body portion 56A and is orthogonal to the first side portion 56C. The first side portion 56C and the second side portion 56D are formed by bending relative to the main body portion 56A.

[0035] The pair of elastic components 58, 58 are coil springs having a predetermined spring constant. The pair of elastic components 58, 58 are supported on the main body 56A and support the base 10A from below. The lower end of the elastic component 58 is fixed to the main body 56A. The upper end of the elastic component 58 is not fixed to the base 10A, and supports the base 10A by contact. That is, when the pair of elastic components 58, 58 are in a state of being contracted in contact with both the main body 56A and the base 10A, they apply force to the main body 56A and the base 10A in a direction away from each other. The elastic component 58 has the function of reducing vibrations transmitted between components in contact with each other. In addition, the elastic component 58 may be fixed to the base 10A and can be arranged in contact with or separated from the main body 56A.

[0036] The second support portion 40 includes an elastic member (second buffer portion) 48 that supports the base portion 10A from below in a vertically movable manner. When viewed from above from the vertical direction, it is located on the other side of the width direction perpendicular to the travel direction of the overhead transfer vehicle 1 (the side opposite the first support portion 50 in the width direction). In this embodiment, the second support portion 40 is located on the left side of the lifting device 10 in the left-right direction. The second support portion 40 includes connecting members 41, 41, a swinging member 43, a third main body member 45, a fourth main body member 46, a restricting member 47, and a pair of elastic members 48, 48.

[0037] The connecting members 41, 41 are members to which the belts 9, 9 are attached. The swinging member 43 connects the pair of connecting members 41, 41 and the third main body member 45. The pair of connecting members 41, 41 and the swinging member 43 are connected to each other so as to be rotatable in both directions via a pair of pin members 42, 42. The swinging member 43 is connected to the third main body member 45 so as to be rotatable in both directions via a pin member 44.

[0038] like Figure 5 (A) Figure 5 (B) and Figure 7 As shown, the fourth main body member 46 includes a main body portion 46A, a first side portion 46C, and a second side portion 46. The main body portion 46A supports the elastic members 48, 48 from below. The main body portion 46A is a flat plate-shaped member that supports the elastic members 48, 48 from below. The first side portion 46C is vertically extending from the main body portion 46A. The second side portion 46D is vertically extending from the main body portion 46A and is perpendicular to the first side portion 46C. The first side portion 46C and the second side portion 46D are formed by bending relative to the main body portion 46A.

[0039] The pair of elastic members 48, 48 are coil springs having a predetermined spring constant. The pair of elastic members 48, 48 are supported by the main body 46A and support the base 10A from below. The lower end of the elastic member 48 is fixed to the main body 46A. The limiting member 47 (see Figure 7 ) limits the base portion 10A and the main body 46A from being separated by more than a specified distance. In more detail, the limiting component 47 locks the upper surface of the base portion 10A that is to be separated from the main body 46A by more than a specified distance. The upper end of the elastic component 48 is not fixed to the base portion 10A, and supports the base portion 10A by contact. That is, when the pair of elastic components 48 and 48 are in contact with both the main body 46A and the base portion 10A, they apply force to the main body 46A and the base portion 10A in directions away from each other. The elastic component 48 has the function of reducing vibrations transmitted between components that are in contact with each other. In addition, the elastic component 48 can also be fixed to the base portion 10A and can be set in contact with and separated from the main body 46A.

[0040] like Figure 4 As shown, the link mechanism 70 connects the first support portion 50 and the second support portion 40 and operates so that the vertical distance (first distance) between the first support portion 50 and the base portion 10A and the vertical distance (second distance) between the second support portion 40 and the base portion 10A are close to each other. The link mechanism 70 will be described in detail below.

[0041] The link mechanism 70 includes a first shaft (third buffer portion) 71 , a second shaft (third buffer portion) 72 , a third shaft 73 , a first bushing 81 , a second bushing 82 , a first block 83 , and a second block 84 .

[0042] like Figure 3 、 Figure 4 、 Figure 5 (A) and Figure 5 As shown in (B), the first shaft 71 is supported by the first bushing 81 provided on the second side surface portion 46D of the fourth main body component 46 in the second support portion 40, and extends in the front-to-back direction. The first shaft 71 is inserted into the insertion hole 81A of the first bushing 81, and is arranged to be rotatable and axially slidable relative to the first bushing 81. The material of the first bushing 81 is appropriately selected so that the shaft portion 71C of the first shaft 71 has a specified rotational property and a specified sliding property. The first shafts 71, 71 are arranged at both ends of the second support portion 40 in the front-to-back direction. The two first shafts 71, 71 arranged in the front-to-back direction are arranged on a substantially straight line in the front-to-back direction.

[0043] The first shaft 71 includes a first main body 71A, a second main body 71B, and a shaft 71C. The first main body 71A is connected to one end of the third shaft 73 and is integrally formed with the shaft 71C. The diameter of the first main body 71A is larger than that of the shaft 71C. The second main body 71B is formed so that it can be fitted over the shaft 71C and can move relative to the shaft 71C. The diameter of the second main body 71B is larger than that of the shaft 71C. An elastic member (third buffer) 75 fits over the shaft 71C and is positioned between the first main body 71A and the second main body 71B. The elastic member 75 is a coil spring with a predetermined spring constant that urges the second main body 71B relative to the second side surface 46D of the fourth main body 46. A stopper 71D is provided at one end of the shaft 71C to prevent the first shaft 71 from tilting. The stopper 71D is formed of a material that allows it to slide in the front-to-back direction relative to the main body 46A of the fourth main body 46.

[0044] The first shaft 71 of such a structure can relatively move the second support portion 40 from a fixed position relative to the base portion 10A in the forward and backward direction (travel direction). Figure 4As shown, a pair of elastic members 75, 75, disposed across the second support portion 40 in the front-to-back direction, function to return the second support portion 40, which has moved from its predetermined position relative to the base portion 10A to the front-to-back direction (the direction of travel), to the predetermined position. For example, if the second support portion 40 moves relative to the base portion 10A from its predetermined position to the front side in the front-to-back direction, the elastic member 75 disposed on the first shaft 71, which is disposed at the front side in the front-to-back direction, is compressed. The second support portion 40 returns to its predetermined position relative to the base portion 10A due to the rebound force of the elastic member 75 at this time. Furthermore, for example, if the second support portion 40 moves relative to the base portion 10A from its predetermined position to the rear side in the front-to-back direction, the elastic member 75 disposed on the first shaft 71, which is disposed at the rear side in the front-to-back direction, is compressed. The second support portion 40 returns to its predetermined position relative to the base portion 10A due to the rebound force of the elastic member 75 at this time.

[0045] like Figure 3 、 Figure 4 、 Figure 6 (A) and Figure 6 As shown in (B), the second shaft 72 is supported by the second bushing 82 provided on the second side surface portion 56D of the second main body member 56 in the first support portion 50, and extends in the front-to-back direction. The second shaft 72 is inserted into the insertion hole 82A of the second bushing 82, and is arranged to be rotatable and axially slidable relative to the second bushing 82. The material of the second bushing 82 can be appropriately selected so that the shaft portion 72C of the second shaft 72 has a specified rotational property and a specified sliding property. The second shafts 72, 72 are arranged at both ends of the first support portion 50 in the front-to-back direction. The two second shafts 72, 72 arranged in the front-to-back direction are arranged on a substantially straight line in the front-to-back direction.

[0046] The second shaft 72 has a first main body 72A, a second main body 72B and a shaft 72C. The first main body 72A is connected to the other end of the third shaft 73 and is formed integrally with the shaft 72C. The diameter of the first main body 72A is larger than the diameter of the shaft 72C. The second main body 72B is formed so as to be able to be externally mounted on the shaft 72C and to be movable relative to the shaft 72C. The diameter of the second main body 72B is larger than the diameter of the shaft 72C. The elastic component (third buffer portion) 76 is externally mounted on the shaft 72C and is arranged between the first main body 72A and the second main body 72B. The elastic component 76 is a coil spring having a predetermined spring constant, and applies force to the second main body 72B relative to the second side surface 56D of the second main body 56.

[0047] The second shaft 72 of such a structure can relatively move the first support portion 50 from a fixed position relative to the base portion 10A in the forward and backward direction (travel direction). Figure 4As shown, a pair of elastic members 76, 76, disposed across the first support portion 50 in the front-to-back direction, function to return the second support portion 40, which has moved from its predetermined position relative to the base portion 10A to the front-to-back direction (the direction of travel), to its predetermined position. For example, if the first support portion 50 moves relative to the base portion 10A from its predetermined position to the front side in the front-to-back direction, the elastic member 76 disposed on the second shaft 72, which is disposed at the front side in the front-to-back direction, is compressed. The first support portion 50 returns to its predetermined position relative to the base portion 10A due to the rebound force of the elastic member 76. Furthermore, if the first support portion 50 moves relative to the base portion 10A from its predetermined position to the rear side in the front-to-back direction, the elastic member 76 disposed on the second shaft 72, which is disposed at the rear side in the front-to-back direction, is compressed. The first support portion 50 returns to its predetermined position relative to the base portion 10A due to the rebound force of the elastic member 76.

[0048] like Figure 3 、 Figure 4 、 Figure 5 (A) Figure 5 (B) Figure 6 (A) and Figure 6 As shown in FIG. 1B , the third shaft 73 is supported by a first block 83 and a second block 84 fixed to the bottom surface of the base portion 10A, extending in the left-right direction. The third shafts 73 are arranged in the front-to-back direction, with the two third shafts 73 and 73 arranged in parallel. The third shaft 73 is inserted through the insertion hole 83A of the first block 83 and the insertion hole 84A of the second block 84, and is arranged to be rotatable relative to the first block 83 and the second block 84 and slidable in the axial direction.

[0049] One end of the third shaft 73 in the left-right direction is connected to the first shaft 71, and the other end of the third shaft 73 is connected to the second shaft 72. Specifically, one end of the third shaft 73 is connected by inserting into the insertion hole formed on the first shaft 71, and the other end of the third shaft 73 is connected by inserting into the insertion hole formed on the second shaft 72.

[0050] Next, mainly use Figure 3 、 Figure 4 、 Figure 5 (A) Figure 5 (B) Figure 6 (A) and Figure 6(B) illustrates an example of the operation of the first support portion 50. When the holding device 11 grips a FOUP 90 containing objects or an empty FOUP 90, a load acts on the elastic member 58, compressing it. The compression of the elastic member 58 generates a rebound force, which applies force to the base portion 10A. Vibration transmitted to the FOUP 90 via the holding device 11 during travel of the travel drive unit 3 or during elevation of the lifting device 10 is reduced by the elastic member 58 provided on the first support portion 50.

[0051] Next, an example of the operation of the second support portion 40 will be described. When the holding device 11 grips a FOUP 90 containing stored objects or an empty FOUP 90, a load acts on the elastic member 48, compressing it. The compression of the elastic member 48 generates a rebound force, which applies force to the base portion 10A. Vibration transmitted to the FOUP 90 via the holding device 11 during travel by the travel drive unit 3 or during elevation of the lifting device 10 is reduced by the elastic member 48 provided on the second support portion 40.

[0052] Next, an example of the operation of the link mechanism 70 connecting the second support portion 40 and the first support portion 50 arranged in the left-right direction will be described. For example, assume that due to centrifugal force during driving, a force acts on the elastic members 48, 48 of the left second support portion 40. When this force acts on the elastic members 48, 48 of the second support portion 40, the elastic members 48, 48 are compressed, and the fourth main body member 46 moves upward (arrow D1). In other words, the distance between the fourth main body member 46 and the base portion 10A decreases. In this operation, upward movement refers to relative movement toward the base portion 10A, while downward movement refers to relative movement away from the base portion 10A. When the fourth main body member 46 moves upward, the end of the first shaft 71, which is fixed to the fourth main body member 46 via the first bushing 81, on the side closest to the first bushing 81, moves upward (arrow D2), and the end of the first shaft 71 connected to the third shaft 73 moves downward (arrow D3).

[0053] If the end of the first shaft 71 on the side of the third shaft 73 moves downward, the third shaft 73 also moves downward (arrow D4). If the third shaft 73 moves downward, the end of the second shaft 72 on the side of the third shaft 73, which is connected to the third shaft 73 and fixed to the second main body component 56 via the second bushing 82, moves downward (arrow D5), and the end on the side of the second bushing 82 moves upward (arrow D6). As a result, the second main body component 56 is pushed upward (arrow D7). If the second main body component 56 is pushed upward, the elastic members 58, 58 of the first support portion 50 are compressed, and the distance between the first main body component 54 and the base portion 10A is shortened.

[0054] On the other hand, when the elastic members 48, 48 are pulled and extend, the fourth main body member 46 moves downward (in the direction opposite to arrow D1). Specifically, the distance between the fourth main body member 46 and the base portion 10A increases. When the fourth main body member 46 moves downward, the end of the first shaft 71, which is fixed to the fourth main body member 46 via the first bushing 81, on the side closest to the first bushing 81 moves downward (in the direction opposite to arrow D2), and the end of the first shaft 71 connected to the third shaft 73 moves upward (in the direction opposite to arrow D3).

[0055] If the end of the first shaft 71 on the side of the third shaft 73 moves upward, the third shaft 73 also moves upward (in the direction opposite to arrow D4). If the third shaft 73 moves upward, the end of the second shaft 72 on the side of the third shaft 73, which is connected to the third shaft 73 and fixed to the second main body component 56 by the second bushing 82, moves upward (in the direction opposite to arrow D5), and the end on the side of the second bushing 82 moves downward (in the direction opposite to arrow D6). As a result, the second main body component 56 is pressed downward (to the side opposite to arrow D7). If the second main body component 56 is pressed downward, the elastic members 58, 58 of the first support portion 50 extend, and the distance between the first main body component 54 and the base portion 10A increases.

[0056] In this manner, in the link mechanism 70 connecting the second support portion 40 and the first support portion 50 aligned in the left-right direction, when the elastic members 48, 48 of the second support portion 40 and the elastic members 58, 58 of the first support portion 50 contract or extend, the third shaft 73 rotates accordingly about the first block 83 and the second block 84 fixed to the bottom surface of the base portion 10A, thereby contracting or extending the elastic members 48, 48 of the second support portion 40 and the elastic members 58, 58 of the first support portion 50. In other words, when a difference arises between the distance between the base portion 10A and the fourth main body member 46 and the distance between the base portion 10A and the first main body member 54 in the second support portion 40 and the first support portion 50 connected to each other, the link mechanism 70 operates so that the distance between the base portion 10A and the fourth main body member 46 and the distance between the base portion 10A and the first main body member 54 in the second support portion 40 and the first support portion 50 connected to each other are closer.

[0057] The link mechanism 70 includes a third shaft 73 that generates stress (torsional stress) when a difference occurs between the distance between the base 10A and the fourth main body member 46 and the distance between the base 10A and the first main body member 54. The reaction force to the stress generated on the third shaft 73 acts as a force that reduces the distance between the base 10A and the fourth main body member 46 and the distance between the base 10A and the first main body member 54.

[0058] The effects of the overhead transfer vehicle 1 according to the above embodiment will now be described. The overhead transfer vehicle 1 according to the above embodiment includes a link mechanism 70 that operates to approximate the vertical distance between the first support 50 and the base 10A and the vertical distance between the second support 40 and the base 10A. This prevents the lift 10 (base 10A) from rolling. Consequently, the left-right tilt of the base 10A can be reduced, suppressing any FOUP 90 wobbling.

[0059] Furthermore, elastic members 48 and 58 are provided on the first and second support portions 50 and 40 to enable vertical movement of the base portion 10A relative to the first and second support portions 50 and 40, thereby reducing vertical vibration transmitted to the FOUP 90 via the lifting device 10. Furthermore, the link mechanism 70 allows horizontal movement of the base portion 10A relative to the first support portion 50 while constantly applying a force to return it to a fixed (neutral) position by the elastic members 76 and 76. Furthermore, the link mechanism 70 allows horizontal movement of the base portion 10A relative to the second support portion 40 while constantly applying a force to return it to a fixed position by the elastic members 75 and 75. This reduces horizontal vibration, more specifically, front-to-back vibration, transmitted to the FOUP 90 via the lifting device 10. As a result, vibration transmitted to the FOUP 90 can be further reduced, while suppressing any swaying of the FOUP 90.

[0060] In the overhead transfer vehicle 1 of the above embodiment, the elastic members 48 , 58 , 75 , and 76 are formed of spring members, and therefore, vibration can be reduced efficiently with a simple structure.

[0061] Although one embodiment has been described above, one aspect of the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the invention.

[0062] In the overhead transfer vehicle 1 of the above-mentioned embodiment, the following example is cited for illustration: the first support portion 50 can be moved relative to the base portion 10A in the travel direction and the elastic components 76, 76 are used to always apply a force to return the first support portion 50 to a fixed position. In addition, the second support portion 40 can be moved relative to the base portion 10A in the travel direction and the elastic components 75, 75 are used to always apply a force to return the second support portion 40 to a fixed position. However, on the basis of this structure, the following structure can also be provided: the first support portion 50 and the second support portion 40 can be moved relative to the base portion 10A in the left-right direction and the elastic component 77 is used to always apply a force to return the first support portion 50 and the second support portion 40 to a fixed position.

[0063] Specifically, if Figure 8 As shown, elastic members 77 are disposed on the third shaft (fourth buffer portion) 73 between the first main body 72A and the second block 84, and between the first main body 71A and the first block 83. The third shaft 73 thus configured enables relative movement of the first support portion 50 and the second support portion 40 from a predetermined position relative to the base portion 10A in the left-right direction (width direction). Furthermore, the elastic members 77, 77 disposed at both ends of the third shaft 73 in the left-right direction function to return the first support portion 50 and the second support portion 40, which have moved from a predetermined position relative to the base portion 10A in the left-right direction (width direction), to the predetermined position.

[0064] For example, when the first support portion 50 or the second support portion 40 moves relative to the base portion 10A from its fixed position to the right side in the left-right direction, the elastic member 77 disposed on the right side in the left-right direction is compressed. The first support portion 50 or the second support portion 40 returns to its fixed position relative to the base portion 10A by utilizing the rebound force of the elastic member 77 at this time. Furthermore, for example, when the first support portion 50 or the second support portion 40 moves relative to the base portion 10A from its fixed position to the left side in the left-right direction, the elastic member 77 disposed on the left side in the left-right direction is compressed. The first support portion 50 or the second support portion 40 returns to its fixed position relative to the base portion 10A by utilizing the rebound force of the elastic member 77 at this time. In the overhead transfer vehicle 1 of the structure of this modified example, vibrations in both the front-to-back direction and the left-to-right direction transmitted to the FOUP 90 via the lifting device 10 can be reduced.

[0065] Alternatively, the structure (elastic member 77) of the modified example described above may be used instead of the structure (second shaft 72 and elastic members 76, 76) that enables relative movement of the first support portion 50 relative to the base portion 10A of the overhead transfer vehicle 1 in the travel direction, and the structure (first shaft 71 and elastic members 75, 75) that enables relative movement of the second support portion 40 relative to the base portion 10A in the travel direction. In the overhead transfer vehicle 1 having this modified example structure, left-right vibrations transmitted to the FOUP 90 via the lifting device 10 can be reduced.

[0066] In the above-described embodiments and modifications, coil springs are used as examples of the elastic members 48, 58, 75, 76, and 77. However, a gel-like elastic body made of, for example, silicone resin may be used. Even in this case, vibration and shock absorption can be achieved in the same manner as with the coil springs.

[0067] While the above-described embodiments and modifications illustrate an example in which the first support portion 50 is located on the right side of the lift mechanism 10 in the left-right direction and the second support portion 40 is located on the left side of the upper lift mechanism 10 in the left-right direction, this is not limiting. For example, the overhead transfer vehicle 1 may have a configuration in which the positions of the first support portion 50 and the second support portion 40 are reversed in the left-right direction. Furthermore, the structures of the support portions connecting the belt 9 and the base 10A may be identical, for example, with the first support portion 50 or the second support portion 40 positioned on both sides in the left-right direction.

[0068] Description of Reference Numerals

[0069] 1: Aerial transport vehicle, 2: Travel track (track), 9: Belt (hanging component), 10: Lifting device (lifting part), 10A: Base part, 11: Holding device (holding part), 40: Second supporting part, 48: Elastic component (second buffer part), 50: First supporting part, 58: Elastic component (first buffer part), 70: Link mechanism, 71: First shaft (third buffer part), 72: Second shaft (third buffer part), 73: Third shaft (fourth buffer part), 75: Elastic component (third buffer part), 76: Elastic component (third buffer part), 77: Elastic component (fourth buffer part), 90: FOUP (item).

Claims

1. An overhead transport vehicle comprising: a main body capable of traveling along a track; and a lifting unit having a gripping portion for gripping an article and being raised and lowered relative to the main body by a hanging member. The lifting part includes: a base portion, on which the handle portion is mounted; a first support portion having a first buffer portion that supports the base portion from below in a vertical direction so as to be movable in the vertical direction, and connected to the hanging member on one side in a width direction perpendicular to the traveling direction of the main body portion when viewed from above in the vertical direction; a second support portion having a second buffer portion that supports the base portion from below in a vertical direction so as to be movable in the vertical direction, and connected to the hanging member at the other end of the body portion in the width direction; as well as a link mechanism that connects the first support portion and the second support portion and operates so that a first distance in the vertical direction between the first support portion and the base portion and a second distance in the vertical direction between the second support portion and the base portion approach each other, The connecting rod mechanism has at least one of a third buffer portion and a fourth buffer portion, the third buffer portion includes a pair of elastic components arranged across the first support portion in the traveling direction and a pair of elastic components arranged across the second support portion in the traveling direction, and is capable of realizing relative movement of the base portion relative to the first support portion and the second support portion in the traveling direction, and the fourth buffer portion includes elastic components arranged at both ends of the fourth buffer portion in the width direction, and is capable of realizing relative movement of the base portion relative to the first support portion and the second support portion in the width direction.

2. The overhead transfer vehicle according to claim 1, wherein: The link mechanism includes the third buffer portion.

3. The overhead transfer vehicle according to claim 1 or 2, wherein: The link mechanism includes both the third buffer portion and the fourth buffer portion.

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