stacker crane

Abstract

A stacker crane (6) is provided with a travel unit (70) having: a drive wheel which is at least one of a first wheel (72) and a second wheel (73) disposed so as to oppose each other with a rail (5) therebetween; and a movement mechanism (80) for moving the drive wheel. The movement mechanism (80) has a first contact pressure regulating mechanism (83) and a second contact pressure regulating mechanism (84) that regulate the contact pressure of the drive wheel on the rail (5) by moving the drive wheel in a direction in which the first wheel (72) and the second wheel (73) move apart from each other or close to each other. One of the first contact pressure regulating mechanism (83) and the second contact pressure regulating mechanism (84) is disposed on one side of the drive wheel in the traveling direction of the travel unit (70), whereas the other of the first contact pressure regulating mechanism (83) and the second contact pressure regulating mechanism (84) is disposed on the other side of the drive wheel in the travel direction.

Description

[Technical Field]

[0001] One aspect of the present invention relates to a stacker crane. [Background technology]

[0002] For example, Patent Document 1 discloses a stacker crane that can pressurize the drive wheels against the rails using a biasing mechanism that biases one of a pair of wheels that sandwich the rail toward the rail. In such a stacker crane, the contact pressure of the drive wheels against the rails can be increased, reducing slippage of the drive wheels on the rails and enabling higher travel speeds and greater acceleration and deceleration. In addition, in such a stacker crane, the stacker lane can be manually moved by releasing the contact pressure of the drive wheels against the rails. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6011628 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the biasing mechanism of the conventional stacker crane is provided in a portion of the drive wheel in the travel direction, which can make it difficult for an operator to reach depending on the stopping position of the stacker crane, and adjusting the biasing mechanism can be time-consuming.

[0005] Therefore, an object of one aspect of the present invention is to provide a stacker crane that can improve the workability when adjusting the contact pressure of the drive wheels. [Means for solving the problem]

[0006] A stacker crane according to one aspect of the present invention comprises a running section having a drive wheel, which is at least one of a first wheel and a second wheel, arranged opposite each other on either side of a rail, and a movement mechanism for moving the drive wheel, the movement mechanism having a first contact pressure adjustment mechanism and a second contact pressure adjustment mechanism that adjusts the contact pressure of the drive wheel against the rail by moving the drive wheel in a direction in which the first wheel and the second wheel move away from or towards each other, one of the first contact pressure adjustment mechanism and the second contact pressure adjustment mechanism being arranged on one side of the drive wheel in the running direction of the running section, and the other of the first contact pressure adjustment mechanism and the second contact pressure adjustment mechanism being arranged on the other side of the drive wheel in the running direction.

[0007] A stacker crane with this configuration is provided with a first contact pressure adjustment mechanism and a second contact pressure adjustment mechanism on both sides in the travel direction of the first and second wheels to adjust the contact pressure of the drive wheels against the rail. This allows the operator to adjust the contact pressure of the drive wheels from both sides in the travel direction of the drive wheels. As a result, the workability when adjusting the contact pressure of the drive wheels can be improved.

[0008] In a stacker crane according to one aspect of the present invention, the movement mechanism has a rotating member that is rotatable about a rotation axis relative to the main body of the running section and to which the axle of the first wheel is fixed, the first contact pressure adjustment mechanism may be a mechanism that moves a portion of the rotating member in a direction away from or toward the rail, and the second contact pressure adjustment mechanism may be a mechanism that moves another portion different from the portion of the rotating member in a direction away from or toward the rail. With this configuration, with a simple configuration, an operator can move the first wheel and the second wheel from both sides in the direction of travel of the wheels so that they move away from or toward each other.

[0009] In a stacker crane according to one aspect of the present invention, the rotating shaft may be positioned closer to the rail than the axle of the first wheel, and the running unit may be arranged in the following order from one side in the traveling direction: first contact pressure adjustment mechanism, rotating shaft, axle of the first wheel, and second contact pressure adjustment mechanism. This configuration allows the contact pressure of the drive wheels to be adjusted with a simple configuration.

[0010] In a stacker crane according to one aspect of the present invention, the first contact pressure adjustment mechanism moves a portion of the rotating member closer to the rail to move the first wheel away from the rail, and the second contact pressure adjustment mechanism moves another portion different from the portion of the rotating member closer to the rail to move the first wheel closer to the rail. This configuration makes it possible to adjust the contact pressure of the drive wheels with a simple configuration.

[0011] A stacker crane according to one aspect of the present invention may further include a mast provided at one end of the traveling section in the traveling direction and extending vertically, and a transfer unit provided on the mast so as to be vertically movable along one side surface on the other side in the traveling direction, wherein the first wheel and the second wheel are disposed in the traveling direction between the mast and the other end of the traveling section in the traveling direction. In this configuration, the first wheel and the second wheel are disposed near the center of the traveling section, and the distance from both ends of the traveling section to the first wheel and the second wheel in the traveling direction is long. However, in the stacker crane according to one aspect of the present invention, the first contact pressure adjustment mechanism and the second contact pressure adjustment mechanism are provided on both sides of the traveling section in the traveling direction, so that the contact pressure of the drive wheels can be easily adjusted even in a configuration in which the first wheel and the second wheel are disposed near the center of the traveling section.

[0012] In a stacker crane according to one aspect of the present invention, the running section may have a lower running section disposed at the vertical lower end of the mast and an upper running section disposed at the vertical upper end of the mast, and the movement mechanism may be provided on the upper running section. This configuration improves the operability when adjusting the contact pressure of the drive wheels disposed on the upper running section disposed at the vertical upper end of the mast. [Effects of the Invention]

[0013] According to one aspect of the present invention, it is possible to improve the workability when adjusting the contact pressure of the drive wheels. [Brief explanation of the drawings]

[0014] [Figure 1]FIG. 1 is a side view showing a schematic configuration of a stocker in which a stacker crane according to one embodiment is installed. [Figure 2] FIG. 2 is a side view showing a schematic configuration of the stocker of FIG. [Figure 3] FIG. 3 is a perspective view showing a stacker crane according to one embodiment. [Figure 4] 4 is a perspective view of the upper run of FIG. 3. FIG. [Figure 5] FIG. 5 is a plan view of the upper run of FIG. [Figure 6] 6 is a side view of the upper run of FIG. 3. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0015] A stocker 1 equipped with a stacker crane 6 according to one embodiment will be described below with reference to the drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted. For ease of explanation, the X, Y, and Z directions are defined in FIGS. 1 to 6. The X direction is the direction that coincides with the travel direction of the stacker crane, and the Y direction is the direction perpendicular to the X direction and coincides with the width direction of the stocker main body 3. The Z direction is the direction that coincides with both the X and Y directions and coincides with the vertical direction.

[0016] Stocker 1 stores items transported by a transport device, for example. The items are containers such as FOUPs (Front Opening Unified Pods) that store wafers to be processed in semiconductor manufacturing equipment, liquid crystal manufacturing equipment, etc., and reticle pods that store reticles used in semiconductor manufacturing equipment, liquid crystal manufacturing equipment, etc. As shown in FIGS. 1 and 2 , stocker 1 includes a stocker body 3, racks 4, rails 5, and a stacker crane 6.

[0017] The stocker body 3 is formed in the shape of a housing (for example, a hollow rectangular parallelepiped) that encloses a predetermined area extending in the X direction. The outer shape of the stocker body 3 is formed by a frame and panels (not shown). An underfloor area S2, which is part of the internal area of ​​the stocker body 3, is formed at a position lower than the floor surface GL on the outside of the stocker body 3.

[0018] The stocker main body 3 houses racks 4A, 4B and two stacker cranes 6. The racks 4A, 4B are arranged facing each other in the Y direction, sandwiching the travel area S1 of the stacker crane 6. Each of the racks 4A, 4B has a plurality of shelves 41 on which articles can be placed. In each of the racks 4A, 4B, a plurality of shelves 41 are arranged along the X and Y directions.

[0019] The rail 5 is composed of an upper rail (rail) 51 and a lower rail 53. The upper rail 51 and the lower rail 53 are arranged inside the stocker body 3 and are arranged so as to face each other in the vertical direction. The upper rail 51 extends in the horizontal X direction. The upper rail 51 is attached directly to a ceiling or the like, or attached to a ceiling or the like via a hanging member. The lower rail 53 also extends in the horizontal X direction like the upper rail 51. The lower rail 53 is attached directly to the ground or attached to the ground via a support member.

[0020] 2 and 3, each of the two stacker cranes 6, 6 includes a lower running section 61, a mast 63, a transfer section 65, and an upper running section (running section) 70. Since the two stacker cranes 6, 6 have the same configuration, they will be described below simply as stacker crane 6. In the following description, the stacker crane 6 located on the right side in FIG. 1 will be illustrated and described.

[0021] The lower running section 61 runs along the lower rail 53. The lower running section 61 has a lower main body section 61A, a drive wheel 61B, a pair of driven wheels 61C, 61C, a travel motor 61D, and a lifting motor 61E. The lower main body section 61A is composed of members such as a frame and a plate, and supports the drive wheel 61B, the pair of driven wheels 61C, 61C, the travel motor 61D, and the lifting motor 61E. The drive wheel 61B is provided to be able to roll on the upper surface of the lower rail 53. The pair of driven wheels 61C, 61C are provided to be able to roll while sandwiching the side surfaces of the lower rail 53. The travel motor 61D is a drive source for the drive wheel 61B. The lifting motor 61E is a drive source for the transfer section 65.

[0022] The mast 63 is a columnar member extending in the vertical direction. The mast 63 is provided to stand upright from the lower running section 61. The upper end of the mast 63 is connected to the upper running section 70. The mast 63 is disposed at one end of the lower running section 61 in the X direction (the running direction of the stacker crane 6), and is also disposed at one end of the upper running section 70 in the X direction. In other words, the lower running section 61 and the upper running section 70 protrude from the mast 63 to the other side in the X direction.

[0023] The transfer unit 65 transfers articles between the shelves 41 and a loading / unloading port (not shown) provided in the stocker main body 3. The transfer unit 65 is provided so as to be able to move up and down along one side surface (lifting surface 63A) of the mast 63. More specifically, the transfer unit 65 is provided on the other side of the mast 63 in the X direction, i.e., on the same side as the direction in which the lower run unit 61 and the upper run unit 70 protrude from the mast 63. The transfer unit 65 is driven by a lifting motor 61E.

[0024] As shown in Figures 3 to 6, the upper running portion 70 mainly has an upper main body portion 71, a first driving wheel (first wheel) 72, a second driving wheel (second wheel) 73, a moving mechanism 80, a motor 74 for the first driving wheel, a motor 75 for the second driving wheel, a first driven wheel 76, and a second driven wheel 77.

[0025] The upper main body 71 is composed of members such as a frame and a plate, and supports a first drive wheel 72, a second drive wheel 73, a movement mechanism 80, a first drive wheel motor 74, a second drive wheel motor 75, a first driven wheel 76, and a second driven wheel 77. One end of the upper main body 71 in the X direction is connected to the mast 63. As described above, the upper running part 70 is disposed so as to protrude from the mast 63. For ease of explanation, the end of the upper main body 71 on the mast 63 side will be referred to as the base end 71B, and the end of the upper main body 71 opposite the base end 71B will be referred to as the tip end 71E.

[0026] The first drive wheel 72 and the second drive wheel 73 are arranged opposite each other in the Y direction and are adjusted so that they sandwich (hold) the upper rail 51 when the upper running part 70 runs. The first drive wheel 72 and the second drive wheel 73 are provided in the center of the upper main body part 71 in the X direction. More specifically, the first drive wheel 72 and the second drive wheel 73 are arranged between the tip end 71E of the upper main body part 71 and the lifting surface 63A of the mast 63 in the X direction.

[0027] The first drive wheel 72 is a drive wheel driven by a first drive wheel motor 74. The first drive wheel 72 has an axle 72A fixed to a movement mechanism 80 (rotating member 81) which will be described in detail later. The second drive wheel 73 is a drive wheel driven by a second drive wheel motor 75. The second drive wheel 73 has an axle 73A fixed to the upper main body part (main body of the running part) 71.

[0028] The movement mechanism 80 is a mechanism that adjusts the contact pressure of the first drive wheel 72 against the upper rail 51. As shown in Figs. 4 to 6, the movement mechanism 80 has a rotating member 81, a rotating shaft 82, a first contact pressure adjustment mechanism 83, and a second contact pressure adjustment mechanism 84. The upper running section 70 is arranged in the following order from one side in the running direction: the first contact pressure adjustment mechanism 83, the rotating shaft 82, the axle 72A of the first drive wheel 72, and the second contact pressure adjustment mechanism 84.

[0029] The rotating member 81 is provided with respect to the upper main body portion 71 so as to be rotatable about a rotating shaft 82. The rotating shaft 82 is disposed at a position closer to the upper rail 51 in the Y direction than the axle 72A of the first drive wheel 72. The axle 72A of the first drive wheel 72 is fixed to the rotating member 81, and the first drive wheel 72 is provided so as to be rotatable about the axle 72A. The first drive wheel 72 provided on the rotating member 81 moves along the Y direction (in the Y direction while also moving in the X direction) as the rotating member 81 rotates. This makes it possible to adjust the contact pressure of the first drive wheel 72 with the upper rail 51. The rotating member 81 is formed with a first protruding portion 81C that protrudes toward the tip end portion 71E, and a second protruding portion 81D that protrudes toward the base end portion 71B.

[0030] In this embodiment, when the first protrusion 81C is moved toward the upper rail 51, the entire rotating member 81 rotates clockwise around the rotation shaft 82 in a plan view, and the first drive wheel 72 moves away from the upper rail 51 (i.e., the first drive wheel 72 moves in a direction away from the second drive wheel 73). On the other hand, when the first protrusion 81C is moved away from the upper rail 51, the entire rotating member 81 rotates counterclockwise around the rotation shaft 82 in a plan view, and the first drive wheel 72 moves toward the upper rail 51 (i.e., the first drive wheel 72 moves in a direction toward the second drive wheel 73). The rotating member 81 is biased by the second contact pressure adjustment mechanism 84 so as to rotate counterclockwise around the rotation shaft 82 in a plan view. Note that the "plan view" referred to here means when viewed from above in the axial direction. Hereinafter, even when simply referring to "clockwise" and "counterclockwise," these terms also mean "clockwise" and "counterclockwise" in a plan view.

[0031] The first contact pressure adjustment mechanism 83 is a mechanism that moves the first protruding portion (part of the rotating member) 81C of the rotating member 81 in the Y direction. In other words, the first contact pressure adjustment mechanism 83 is a mechanism that adjusts the contact pressure of the first driving wheel 72 against the upper rail 51 by moving the first driving wheel 72 in the Y direction.

[0032] The first contact pressure adjustment mechanism 83 has a bolt 83A and a fixed portion 83B. The bolt 83A is threadedly engaged with the fixed portion 83B. In the first contact pressure adjustment mechanism 83, by rotating the bolt 83A clockwise, the tip of the bolt 83A moves closer to the upper rail 51 and presses the block portion 81A of the rotating member 81. As a result, the rotating member 81 rotates clockwise around the rotation shaft 82, and with this rotation, the first drive wheel 72 moves away from the upper rail 51 (i.e., the first drive wheel 72 moves in a direction away from the second drive wheel 73). As a result, the predetermined contact pressure state of the first drive wheel 72 against the upper rail 51 is released.

[0033] Furthermore, in first contact pressure adjustment mechanism 83, by rotating bolt 83A counterclockwise, the tip of bolt 83A moves away from upper rail 51. As a result, rotating member 81, which is biased by compression spring 84C to rotate counterclockwise, rotates counterclockwise about rotating shaft 82, and as a result of this rotation, first drive wheel 72 approaches upper rail 51 (i.e., first drive wheel 72 moves in a direction approaching second drive wheel 73). As a result, first drive wheel 72 comes into contact with upper rail 51 at a predetermined pressure.

[0034] Furthermore, in this embodiment, when the second protrusion 81D is moved toward the upper rail 51, the entire rotating member 81 rotates counterclockwise around the rotating shaft 82, and the first drive wheel 72 moves toward the upper rail 51 (i.e., the first drive wheel 72 moves in a direction toward the second drive wheel 73). On the other hand, when the second protrusion 81D is moved away from the upper rail 51, the entire rotating member 81 rotates clockwise around the rotating shaft 82, and the first drive wheel 72 moves away from the upper rail 51 (i.e., the first drive wheel 72 moves in a direction away from the second drive wheel 73).

[0035] The second contact pressure adjustment mechanism 84 is a mechanism that moves in the Y direction the second protruding portion 81D (a part different from the part of the rotating member) of the rotating member 81. In other words, the second contact pressure adjustment mechanism 84 is a mechanism that adjusts the contact pressure of the first drive wheel 72 against the upper rail 51 by moving the first drive wheel 72 in the Y direction.

[0036] The second contact pressure adjustment mechanism 84 has a bolt 84A, a fixed portion 84B, and a compression spring 84C. The bolt 84A is threadedly engaged with the fixed portion 84B. In the second contact pressure adjustment mechanism 84, by rotating the bolt 84A clockwise, the compression spring 84C attached to the tip of the bolt 84A moves toward the upper rail 51 and presses the block portion 81B of the rotating member 81. As a result, the rotating member 81 rotates counterclockwise about the rotation shaft 82, and as a result of this rotation, the first drive wheel 72 moves toward the upper rail 51 (i.e., the first drive wheel 72 moves in a direction toward the second drive wheel 73). As a result, the first drive wheel 72 is placed in contact with the upper rail 51 at a predetermined pressure.

[0037] Furthermore, in second contact pressure adjustment mechanism 84, by rotating bolt 84A counterclockwise, the pressing force of compression spring 84C attached to the tip of bolt 83A against block portion 81B is weakened. This enables rotating member 81 to rotate clockwise around rotating shaft 82, and as this rotation occurs, first drive wheel 72 moves away from upper rail 51 (i.e., first drive wheel 72 moves in a direction away from second drive wheel 73). As a result, the predetermined contact pressure state of first drive wheel 72 against upper rail 51 is released.

[0038] One of the first contact pressure adjustment mechanism 83 and the second contact pressure adjustment mechanism 84 is arranged on one side of the first drive wheel 72 in the running direction (X direction) of the upper running part 70, and the other of the first contact pressure adjustment mechanism 83 and the second contact pressure adjustment mechanism 84 is arranged on the other side of the first drive wheel 72 in the running direction. In this embodiment, the first contact pressure adjustment mechanism 83 is arranged closer to the tip end 71E of the upper main body part 71 than the first drive wheel 72, and the second contact pressure adjustment mechanism 84 is arranged closer to the base end part 71B of the upper main body part 71 than the first drive wheel 72.

[0039] The effects of the stacker crane 6 of the above embodiment will be described. The stacker crane 6 of the above embodiment is provided with a first contact pressure adjustment mechanism 83 and a second contact pressure adjustment mechanism 84 on both sides in the traveling direction of the first drive wheel 72 and the second drive wheel 73, respectively, to adjust the contact pressure of the first drive wheel 72 against the upper rail 51. This allows an operator to adjust the contact pressure of the first drive wheel 72 from both sides in the traveling direction of the first drive wheel 72. For example, if the stacker crane 6 breaks down and becomes unable to move by itself, the operator can operate one of the first contact pressure adjustment mechanism 83 and the second contact pressure adjustment mechanism 84 to release the contact pressure of the first drive wheel 72 against the upper rail 51, and manually move the stacker crane 6. As a result, the workability when adjusting the contact pressure of the first drive wheel 72 can be improved.

[0040] In the stacker crane 6 of the above embodiment, the first contact pressure adjustment mechanism 83 is a mechanism that moves in the Y direction the first protruding portion 81C that is part of the rotating member 81, and the second contact pressure adjustment mechanism 84 is a mechanism that moves in the Y direction the second protruding portion 81D that is another part different from the part of the rotating member 81. With this simple configuration, the first drive wheel 72 can be moved in the Y direction from both sides in the traveling direction of the first drive wheel 72.

[0041] In the stacker crane 6 of the above embodiment, the rotating shaft 82 of the rotating member 81 is disposed at a position closer to the upper rail 51 than the axle 72A of the first drive wheel 72, and the upper running section 70 is disposed, from one side in the traveling direction (the tip end 71E side), with the first contact pressure adjustment mechanism 83, the rotating shaft 82, the axle 72A of the first drive wheel 72, and the second contact pressure adjustment mechanism 84 arranged in this order. This makes it possible to adjust the contact pressure of the first drive wheel 72 with a simple configuration.

[0042] In the stacker crane 6 of the above embodiment, the first contact pressure adjustment mechanism 83 moves the first drive wheel 72 away from (away from) the upper rail 51 by moving the first protruding portion 81C closer to the upper rail 51, and the second contact pressure adjustment mechanism 84 moves the second protruding portion 81D closer to the upper rail 51, thereby moving the first drive wheel 72 closer to the upper rail 51. This makes it possible to adjust the contact pressure of the first drive wheel 72 with a simple configuration.

[0043] In the stacker crane 6 of the above embodiment, the first drive wheel 72 is disposed between the tip 71E of the upper run 70 (upper main body 71) in the running direction and the mast 63. In this configuration, the first drive wheel 72 is disposed near the center of the upper run 70, and the distance from the tip 71E and base 71B, which are both ends of the upper run 70 in the running direction, to the first drive wheel 72 is long. However, in the stacker crane 6 of the above embodiment, the first contact pressure adjustment mechanism 83 and the second contact pressure adjustment mechanism 84 are provided on both sides of the upper run 70 in the running direction, so that the contact pressure of the first drive wheel 72 can be easily adjusted even in a configuration in which the first drive wheel 72 is disposed near the center of the upper run 70.

[0044] In the stacker crane 6 of the above embodiment, the workability can be improved when adjusting the contact pressure of the first drive wheel 72 arranged on the upper running portion 70 arranged at the vertical upper end of the mast 63.

[0045] Although one embodiment has been described above, one aspect of the present invention is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the invention.

[0046] In the above embodiment, an example has been described in which, of the two first drive wheels 72 and second drive wheels 73 that sandwich the upper rail 51, only the first drive wheel 72 is provided so as to be movable along the Y direction, but the second drive wheel 73 may also be provided so as to be movable along the Y direction in a similar manner. That is, in addition to the configuration of the stacker crane 6 in the above embodiment, a movement mechanism 80 dedicated to the second drive wheel 73 may be provided.

[0047] In addition, in the above embodiment, an example was given in which two first driving wheels 72 and a second driving wheel 73 are provided to sandwich the upper rail 51, but instead of the second driving wheel 73, a driven wheel that does not have driving force may be arranged.

[0048] Furthermore, in the above embodiment and modified example, an example has been given of a movement mechanism 80 configured to move the first drive wheel 72 in the Y direction by rotating the rotating member 81, and an example has been described in which a first contact pressure adjustment mechanism 83 and a second contact pressure adjustment mechanism 84 are provided as means for rotating the rotating member 81. However, one aspect of the present invention is not limited to this configuration. For example, a configuration may be used in which the first drive wheel 72 is moved in the Y direction by moving a slide member in the Y direction, and a first contact pressure adjustment mechanism 83 and a second contact pressure adjustment mechanism 84 are provided to move the slide member.

[0049] Furthermore, in the above embodiment and modified example, an example in which one aspect of the present invention is applied to the upper running portion 70 has been described, but one aspect of the present invention may also be applied to the lower running portion 61 instead of or in addition to this configuration. [Explanation of symbols]

[0050] 1...stocker, 5...rail, 6...stacker crane, 51...upper rail (rail), 63...mast, 65...transfer section, 70...upper running section (running section), 71...upper main body section (main body of running section), 72...first driving wheel (first wheel), 73...second driving wheel (second wheel), 74...motor for first driving wheel, 75...motor for second driving wheel, 76...first driven wheel, 77...second driven wheel, 80...movement mechanism, 81...rotating member, 81C...first protrusion (part of the rotating member), 81D...second protrusion (other part different from part of the rotating member), 82...rotating shaft, 83...first contact pressure adjustment mechanism, 84...second contact pressure adjustment mechanism.

Claims

1. a travel unit including a drive wheel, which is at least one of a first wheel and a second wheel, arranged opposite to each other across a rail, and a movement mechanism that moves the drive wheel; the movement mechanism includes a first contact pressure adjustment mechanism and a second contact pressure adjustment mechanism that adjusts the contact pressure of the drive wheel against the rail by moving the drive wheel in a direction in which the first wheel and the second wheel move toward or away from each other, A stacker crane, wherein one of the first contact pressure adjustment mechanism and the second contact pressure adjustment mechanism is arranged on one side of the drive wheel in the running direction of the running part, and the other of the first contact pressure adjustment mechanism and the second contact pressure adjustment mechanism is arranged on the other side of the drive wheel in the running direction.

2. the moving mechanism includes a rotating member that is rotatable about a rotation axis relative to the main body of the traveling unit and to which an axle of the first wheel is fixed, 2. The stacker crane according to claim 1, wherein the first contact pressure adjustment mechanism is a mechanism that moves a portion of the rotating member in a direction away from or toward the rail, and the second contact pressure adjustment mechanism is a mechanism that moves another portion different from the portion of the rotating member in a direction away from or toward the rail.

3. the pivot shaft is disposed at a position closer to the rail than the axle of the first wheel, 3. The stacker crane according to claim 2, wherein the traveling section is arranged in the following order from one side in the traveling direction: the first contact pressure adjustment mechanism, the rotating shaft, the axle of the first wheel, and the second contact pressure adjustment mechanism.

4. the first contact pressure adjustment mechanism moves a part of the rotating member toward the rail to move the first wheel away from the rail, The stacker crane according to claim 3 , wherein the second contact pressure adjustment mechanism moves the first wheel closer to the rail by moving a part different from the part of the rotating member closer to the rail.

5. a mast provided at one end of the traveling section in the traveling direction and extending in a vertical direction; a transfer unit provided on the mast so as to be movable in the vertical direction along one side surface on the other side in the traveling direction, The stacker crane according to any one of claims 1 to 4, wherein the first wheel and the second wheel are arranged in the traveling direction between the other end of the traveling section in the traveling direction and the mast.

6. the running portion includes a lower running portion disposed at a vertically lower end of the mast and an upper running portion disposed at a vertically upper end of the mast, 6. The stacker crane according to claim 5, wherein the moving mechanism is provided on the upper run.

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