Overhead transport vehicle

Abstract

An overhead carrier vehicle (6) comprises: a traveling unit (50) which is equipped with travel wheels (51) that roll on a travel rail (4); and a body unit (7) which is supported by the traveling unit (50) via a suspension unit (8) and which also retains an object (10) being carried. In this overhead carrier vehicle (6), the top surface of the body unit (7) that opposes the travel rail (4) in the vertical direction is provided with a contact roller (61) that comes into contact, from below, with a curved outer-side portion of a curved section (4C) in the travel rail (4).

Description

Technical Field

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[0001] An object of one aspect of the present invention relates to a ceiling transporter.

Background Art

[0002] Ceiling transporters that travel along a running rail installed on the ceiling of a building such as a factory are known. For example, Patent Document 1 discloses a ceiling transporter including a running unit that travels on a running rail and a main body unit that holds an article. In the ceiling transporter of Patent Document 1, the running unit travels inside a tube of a running rail formed in a square tube shape, and the main body unit is suspended and supported with respect to the running unit through a slit provided in the lower surface portion of the running rail.

Prior Art Document

Patent Document

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a ceiling transporter having such a configuration, there is a risk that the running wheels of the running unit may lift off due to centrifugal force when traveling in a curve section, and it may not be possible to travel stably in the curve section.

[0005] Therefore, an object of one aspect of the present invention is to provide a ceiling transporter capable of suppressing the amount of lift of the running wheels when the running unit travels in a curve section.

Means for Solving the Problems

[0006] An overhead transport vehicle according to one aspect of the present invention comprises a running section equipped with running wheels that roll on a running rail, and a main body section supported by the running section via a suspension section and holding the object to be transported, wherein the upper surface of the main body section facing the running rail in the vertical direction is provided with a contact roller that contacts the outer curve portion of the running rail in a curved section from below.

[0007] In an overhead transport vehicle equipped with a main body suspended from a running section, the centrifugal force when traveling on a curve causes the main body to tilt, bringing the outer curve portion of the main body closer to the running rail. However, in an overhead transport vehicle according to one aspect of the present invention, a contact roller is provided on the upper surface of the main body that contacts the outer curve portion of the running rail from below in the curved section. As a result, when the outer curve portion of the main body tries to approach the running rail, the contact roller contacts the outer curve portion of the running rail, and the reaction force at that time restricts the outer curve portion of the main body from approaching the running rail. As a result, tilting of the main body, and consequently tilting of the running section that suspends and supports the main body, is suppressed, and the amount of lift of the running wheels when the running section travels on a curve is suppressed. Note that the outer curve portion of the running rail referred to here means the portion outside the center line in the width direction of the running rail.

[0008] In an overhead transport vehicle according to one aspect of the present invention, the running rail has a slit portion on which the suspension portion can move when the running section is in motion, and a pair of rolling portions on which the running wheels roll, which are arranged to face each other across the slit portion in a width direction perpendicular to both the vertical direction and the direction of travel of the running section. In a curved section, the contact roller may be provided to contact one of the pair of rolling portions which is located on the outside of the curve. In this configuration, in a curved section, the contact roller contacts one of the pair of rolling portions which is located on the outside of the curve. As a result, the reaction force when the contact roller contacts one of the rolling portions restricts the main body from approaching the running rail (rolling portion) on the outside of the curve.

[0009] An overhead transport vehicle according to one aspect of the present invention may further include a lifting mechanism for raising and lowering the contact rollers in the vertical direction. In this configuration, when it is desired to bring the contact rollers into contact with the running rails, the contact rollers can be reliably brought into contact with the running rails, and when it is desired to move the contact rollers away from the running rails, the contact rollers can be reliably moved away from the running rails.

[0010] In an overhead transport vehicle according to one aspect of the present invention, trapezoidal screws may be used as part of the linear motion mechanism that constitutes the lifting mechanism. With this configuration, it is possible to counteract the reaction force when the contact roller contacts the running rail with a simple configuration, without employing complex mechanisms such as a brake mechanism.

[0011] In one aspect of the present invention, an overhead transport vehicle may further include a control unit that controls the lifting mechanism so that the contact rollers contact the rails when the traveling section is traveling through a curved section. In this configuration, the contact rollers can be made to contact the outer curved portion of the rails more reliably in curved sections.

[0012] In an overhead transport vehicle according to one aspect of the present invention, the contact rollers are rotatably mounted, and the orientation of the contact rollers may be pivotable in a direction perpendicular to the axis of rotation when viewed from the vertical. In this configuration, the orientation of the contact rollers can be changed to align with the direction of travel of the travel section, so that the contact rollers rotate well when the overhead transport vehicle is in motion. This prevents the contact rollers from sliding on the travel rails and wearing down due to the travel direction of the travel section and the orientation of the contact rollers not matching.

[0013] In one aspect of the present invention, the overhead transport vehicle may be provided in the center of the main body in the direction of travel of the traveling section. In this configuration, even if the orientation of the contact roller is not oscillating, there is a high probability that the direction of travel of the vehicle and the orientation of the contact roller will coincide in curved sections. This suppresses wear of the contact roller due to the contact roller sliding on the rails caused by the direction of travel of the traveling section and the orientation of the contact roller not coinciding. [Effects of the Invention]

[0014] According to one aspect of the present invention, the amount of lift of the running wheels when the running section travels through a curved section can be suppressed. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a schematic diagram of an overhead transport vehicle system according to one embodiment. [Figure 2] Figure 2 is a front view of the overhead transport vehicle shown in Figure 1, seen from the front. [Figure 3] Figure 3 is a side view of the overhead transport vehicle shown in Figure 1, viewed from the side. [Figure 4] Figure 4 is a cross-sectional view showing an enlarged view of the running rail section in Figure 2. [Figure 5] Figures 5(A), 5(B), and 5(C) illustrate the operation of the tilt suppression mechanism. [Figure 6] Figure 6(A) is a schematic diagram of the tilt suppression mechanism viewed from above. Figure 6(B) is a schematic diagram of the contact roller viewed from above. Figure 6(C) shows the positional relationship between the optical sensor and the shielding plate when viewed from the front. [Figure 7] Figure 7(A) is a perspective view of the contact roller. Figure 7(B) is a perspective view of the contact roller from a different direction than that of Figure 7(A). Figure 7(C) is a side view of the contact roller. [Figure 8] Figures 8(A), 8(B), and 8(C) illustrate the operation of the tilt suppression mechanism provided in the overhead transport vehicle according to a modified example. [Modes for carrying out the invention]

[0016] Hereinafter, an embodiment will be described in detail with reference to the drawings. In the description of the drawings, the same reference numerals are assigned to the same elements, and duplicate descriptions are omitted. In FIGS. 2 to 4, for convenience of explanation, the directions of "up", "down", "left", "right", "front", and "back" are defined. In FIGS. 5 and 6, for convenience of explanation, the X-axis, Y-axis, and Z-axis orthogonal to each other are defined.

[0017] The ceiling transfer vehicle 6 according to this embodiment (hereinafter referred to as "transfer vehicle 6") is used in the ceiling transfer vehicle system 1 as shown in FIG. 1. The ceiling transfer vehicle system 1 is a system for transporting an article (object to be transported) 10 between the placement portions 9 using the transfer vehicle 6 that can move along the travel rail 4. The article 10 includes, for example, containers such as a FOUP (Front Opening Unified Pod) for storing a plurality of semiconductor wafers and a reticle pod for storing a glass substrate, as well as general parts and the like. The ceiling transfer vehicle system 1 includes a travel rail 4, a plurality of transfer vehicles 6, and a plurality of placement portions 9.

[0018] As shown in FIG. 1, the placement portion 9 is arranged along the travel rail 4 and is provided at a position where the transfer vehicle 6 can transfer the article 10. The placement portion 9 includes a buffer and a transfer port. The buffer is a placement portion where the article 10 is temporarily placed. The buffer is, for example, a placement portion where the article 10 is temporarily placed when the transfer vehicle 6 cannot transfer the article 10 being transported to its transfer port due to reasons such as another article 10 being placed on the target transfer port. The transfer port is, for example, a placement portion for transferring the article 10 to a semiconductor processing apparatus (not shown) such as a cleaning apparatus, a film forming apparatus, a lithography apparatus, an etching apparatus, a heat treatment apparatus, and a planarization apparatus. The processing apparatus is not particularly limited and may be various apparatuses.

[0019] For example, the placement unit 9 is arranged on the side of the traveling rail 4. In this case, the carrier vehicle 6 transfers the article 10 to and from the placement unit 9 by laterally feeding the lifting drive unit 28 and the like with the lateral feed unit 24 and raising and lowering the lifting platform 30 (see FIG. 2). Although not shown, the placement unit 9 may be arranged directly below the traveling rail 4. In this case, the carrier vehicle 6 transfers the article 10 to and from the placement unit 9 by raising and lowering the lifting platform 30.

[0020] The traveling rail 4 is laid, for example, near the ceiling which is the overhead space of the operator. The traveling rail 4 is suspended from the ceiling, for example. The traveling rail 4 is a predetermined traveling path for moving the carrier vehicle 6. The carrier vehicle 6 moves along the traveling rail 4 in a predetermined direction. The traveling rail 4 is supported by columns 4A, 4A (see FIG. 2).

[0021] As shown in FIGS. 2 to 4, the traveling rail 4 includes a rectangular tube-shaped rail main body 40 composed of a pair of lower surface portions (rolling portions) 41, 41, a pair of side surface portions 42, 42, and an upper surface portion 43, a power supply unit 45, and a magnetic plate 46. The rail main body 40 forms an internal space S in which the traveling portion 50 of the carrier vehicle 6 travels. The lower surface portion 41 extends in the traveling direction of the carrier vehicle 6 and constitutes the lower surface of the rail main body 40. The lower surface portion 41 is a plate-like member that rolls the traveling rollers (traveling wheels) 51 of the carrier vehicle 6 to make the traveling portion 50 travel. The side surface portion 42 stands upright (intersects) from the lower surface portion 41. The side surface portion 42 extends in the traveling direction of the carrier vehicle 6 and constitutes the side surface of the rail main body 40. The upper surface portion 43 extends in the traveling direction of the carrier vehicle 6 and constitutes the upper surface of the rail main body 40.

[0022] A slit portion G through which the hanging portion 8 of the traveling portion 50, which will be described in detail later, passes during traveling is formed between the pair of lower surface portions 41, 41 facing each other in the width direction (left - right direction) orthogonal to the extending direction of the traveling rail 4. The slit portion G extends along the extending direction of the traveling rail 4. In other words, the pair of lower surface portions 41, 41 are arranged to face each other with the slit portion G interposed therebetween in the width direction.

[0023] The power supply unit 45 supplies power to the power supply core 57 of the transport vehicle 6 and also transmits and receives signals with the power supply core 57. The power supply unit 45 is fixed to each of the pair of side sections 42, 42 and extends along the direction of travel. The power supply unit 45 supplies power to the power supply core 57 in a non-contact manner. The magnetic plate 46 generates a magnetic force for the LDM (Linear DC Motor) 59 of the transport vehicle 6 to move or stop. The magnetic plate 46 is fixed to the top section 43 and extends along the direction of travel.

[0024] The transport vehicle 6 travels along the travel rail 4 and transports the goods 10. The transport vehicle 6 is configured to be able to transfer the goods 10. The transport vehicle 6 is an overhead-traveling unmanned transport vehicle. The number of transport vehicles 6 provided in the overhead transport vehicle system 1 is not particularly limited and can be multiple. The transport vehicle 6 has a main body 7, a travel unit 50, and a main body controller (control unit) 35. The main body 7 has a main body frame 22, a lateral feed unit 24, a θ drive 26, a lifting drive unit 28, a lifting platform 30, and a cover 33.

[0025] The main frame 22 is connected to the travel section 50 via the suspension section 8 and supports the lateral feed section 24, the θ drive 26, the lifting drive section 28, the lifting platform 30, and the cover 33. The lateral feed section 24 moves the θ drive 26, the lifting drive section 28, and the lifting platform 30 together in the width direction (left-right direction) perpendicular to the travel direction of the travel rail 4. The θ drive 26 rotates at least one of the lifting drive section 28 and the lifting platform 30 within a predetermined angular range in the horizontal plane. The lifting drive section 28 raises and lowers the lifting platform 30 by winding or unwinding a suspension material such as a wire, rope, or belt. The lifting platform 30 is provided with a chuck, which allows for easy gripping or release of the article 10. The cover 33 is provided in pairs, for example, at the front and rear in the direction of travel of the transport vehicle 6. The cover 33 extends and retracts claws (not shown) to prevent the article 10 from falling during transport.

[0026] As shown in Figures 3 and 4, the running unit 50 causes the transport vehicle 6 to travel along the running rail 4. The running unit 50 includes a running roller 51, a side roller 52, a branching roller 53, an auxiliary roller 54, an inclined roller 55, a power supply core 57, an LDM 59, and a tilt suppression mechanism 60.

[0027] The running rollers 51 are positioned at both the left and right ends of the front and rear running section 50. The running rollers 51 roll on the inner surfaces 41a, 41a of a pair of lower surfaces 41, 41 of the rail body 40. The side rollers 52 are provided so as to be able to contact the inner surface 42a of the side surface 42 of the rail body 40.

[0028] The branching roller 53 is provided to switch the direction in which the transport vehicle 6 (travel section 50) branches off to the left or right at the branching point of the travel rail 4. More specifically, the branching roller 53 switches the direction in which the transport vehicle 6 travels by being guided by a guide member provided at the branching point.

[0029] The branching roller 53 is provided so as to be able to contact a guide (not shown) located at the connection or branching section of the running rail 4. The auxiliary rollers 54 are groups of three rollers located at the front and rear of the running section 50. The auxiliary rollers 54 are provided to prevent the LDM 59 and power supply core 57, etc. from contacting the magnetic plate 46 located on the upper surface 43 of the running rail 4 when the running section 50 tilts forward or backward due to acceleration or deceleration. The inclined roller 55 is positioned at an angle from the front and rear. The inclined roller 55 is provided to prevent the running section 50 from tilting due to centrifugal force when it travels through a curved section.

[0030] The power supply core 57 is positioned at the front and rear of the running unit 50, sandwiching the LDM 59 in the left-right direction. It provides contactless power supply and transmits and receives various signals with the power supply unit 45 located on the running rail 4. The power supply core 57 exchanges signals with the main controller 35. The LDM 59 is located at the front and rear of the running unit 50. The LDM 59 generates a magnetic force for running or stopping in relation to the magnetic plate 46 located on the upper surface 43 of the running rail 4 using an electromagnet.

[0031] As shown in Figure 1, the running rail 4 is composed of a straight section 4S and a curved section 4C. The tilt suppression mechanism 60 shown in Figures 2 to 4 is a mechanism that suppresses tilting of the running section 50 and the main body 7 due to centrifugal force when the transport vehicle 6 travels through the curved section 4C. The tilt suppression mechanism 60 is provided on the upper surface of the main body 7. The tilt suppression mechanism 60 is a mechanism that suppresses tilting of the main body 7 by bringing the contact roller 61 provided in the tilt suppression mechanism 60 into contact with the outer surface of the lower surface 41 of the running rail 4 from below when traveling through the curved section 4C, and by using the reaction force obtained from the running rail 4.

[0032] As shown in Figure 4, the tilt suppression mechanism 60 is positioned on the upper surface of the main body 7, near both the left and right ends in the width direction. That is, the tilt suppression mechanism 60 is composed of a left tilt suppression mechanism 60A and a right tilt suppression mechanism 60B. The contact roller 61 provided in the left tilt suppression mechanism 60A is positioned to contact the left lower surface portion 41 of the pair of lower surfaces 41, 41 that constitute the running rail 4. The contact roller 61 provided in the right tilt suppression mechanism 60B is positioned to contact the right lower surface portion 41 of the pair of lower surfaces 41, 41 that constitute the running rail 4. As shown in Figure 3, the contact roller 61 provided in the tilt suppression mechanism 60 is located in the central part of the main body 7 in the front-rear direction.

[0033] The contact roller 61 of the tilt suppression mechanism 60 contacts one of the pair of lower surfaces 41, 41 that make up the running rail 4, which is located on the outside of the curve in the curved section 4C. Specifically, when the left lower surface 41 in Figure 4 is located on the outside of the curve in the curved section 4C, the contact roller 61 of the left tilt suppression mechanism 60A contacts the left lower surface 41, and when the right lower surface 41 in Figure 4 is located on the outside of the curve in the curved section 4C, the contact roller 61 of the right tilt suppression mechanism 60B contacts the right lower surface 41.

[0034] As shown in Figures 5(A) and 6(A), the tilt suppression mechanism 60 includes a lifting mechanism 63 that moves the contact roller 61 in the Z-axis direction (up and down in the vertical direction). This allows the tilt suppression mechanism 60 to control whether the contact roller 61 is in contact with the outer surface of the lower surface portion 41 of the running rail 4 or away from the outer surface of the lower surface portion 41.

[0035] The lifting mechanism 63 includes a linear motion mechanism 64 and a rocking mechanism 65. The linear motion mechanism 64 includes a drive unit 64A, a gear 64B, a trapezoidal screw 64C, a support unit 64D, and a moving block 64E. The drive unit 64A is, for example, a motor. The rotational drive in the drive unit 64A is transmitted to the trapezoidal screw 64C via a plurality of gears 64B. The moving block 64E is screwed onto the trapezoidal screw 64C. The moving block 64E in this configuration moves linearly in the X-axis direction as the trapezoidal screw 64C rotates. The moving block 64E is configured such that, for example, when the trapezoidal screw 64C rotates in the positive direction (clockwise), it moves to the left as shown in Figure 5(A), and when the trapezoidal screw 64C rotates in the negative direction (counterclockwise), it moves to the right as shown in Figure 5(A).

[0036] The rocking mechanism 65 includes a first link member 65A, a second link member 65B, a third link member 65C, and a support portion 65D. The first link member 65A is supported by the support portion 65D so as to be movable along the X-axis direction. One end of the first link member 65A is rotatably supported by the moving block 64E, and the other end is rotatably supported by the third link member 65C. The first link member 65A is provided integrally with the moving block 64E so as to be movable along the X-axis direction.

[0037] The second link member 65B is rotatably fixed at one end to the support portion 65D and at the other end to the third link member 65C. An elastic member is provided between the second link member 65B and the support portion 65D to bias the second link member 65B so that it rotates clockwise around the pivot axis of the support portion 65D. The third link member 65C is rotatably fixed to both the other end of the first link member 65A and the other end of the second link member 65B. A contact roller 61 is fixed to the third link member 65C. In this configuration of the linear motion mechanism 64 and the oscillating mechanism 65, if the moving block 64E of the linear motion mechanism 64 moves to the left along the X-axis direction, the height position (position in the Z-axis direction) of the contact roller 61 fixed to the third link member 65C of the oscillating mechanism 65 will decrease (see Figure 5(C)). On the other hand, if the moving block 64E of the linear motion mechanism 64 moves to the right along the X-axis direction, the height position (position in the Z-axis direction) of the contact roller 61 fixed to the third link member 65C of the rocking mechanism 65 rises (see Figure 5(A)).

[0038] As shown in Figure 6(A), the contact roller 61 is attached to the third link member 65C. As shown in Figures 7(A) to 7(C), the contact roller 61 has a rotating part 61A, a rotating support part (rotating shaft) 61B, a first shaft part 61C, a second shaft part 61D, and a spring member 61E. The rotating part 61A is the part that rolls on the lower surface 41 of the running rail 4 and is rotatably provided with respect to the rotating support part 61B. The rotating support part 61B is a ring-shaped member that rotatably supports the rotating part 61A. The first shaft part 61C is the part that passes through the radial center of the rotating support part 61B and extends radially, and is integrally formed with the rotating support part 61B. The first shaft part 61C has a predetermined caster angle. The second shaft part 61D is a member attached to the third link member 65C and is a member that extends in one direction. The first shaft portion 61C is rotatably mounted around the second shaft portion 61D. The rotation support portion 61B is attached to the third link member 65C via a spring member 61E.

[0039] With this configuration of the contact roller 61, as shown in Figure 6(B), the orientation of the contact roller 61 (dash-dot line) is provided so that it can swing with respect to a direction (single dash-dot line) perpendicular to the first shaft portion 61C when viewed from the vertical direction (Z-axis direction). The orientation of the contact roller 61 referred to here is the straight line connecting the front end and the rear end when the contact roller 61 is viewed from above. The contact roller 61 swings, for example, due to the force acting on it from the running rail 4 when it is running on the running rail 4.

[0040] As shown in Figures 1 and 2, the travel unit 50 is controlled by the transport controller 90, which will be described in detail later, via the main unit controller 35. Specifically, commands from the transport controller 90 are transmitted to the main unit controller 35, and the main unit controller 35, upon receiving these commands, controls the travel unit 50.

[0041] The main controller (control unit) 35 is an electronic control unit consisting of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc. The main controller 35 controls various operations of the transport vehicle 6. Specifically, the main controller 35 controls the travel unit 50, the lateral feed unit 24, the θ drive 26, the lifting drive unit 28, the lifting platform 30, and the tilt suppression mechanism 60. The main controller 35 can be configured as software, for example, in which a program stored in ROM is loaded onto RAM and executed by the CPU. The main controller 35 may also be configured as hardware, such as an electronic circuit. The main controller 35 communicates with the transport controller 90 (see Figure 1) using the power supply unit 45 (feeder line) of the travel rail 4.

[0042] In this embodiment, the main unit controller 35 controls the lifting mechanism 63 of the tilt suppression mechanism 60 to switch the position of the contact roller 61 to one of the following states: a first state S1 (the position in which the lifting mechanism 63 raises the contact roller 61 to its maximum height) where the contact roller 61 is in contact with the lower surface 41 of the running rail 4, as shown in Figure 5(A); a second state S2 (the position in which the lifting mechanism 63 raises the contact roller 61 to its maximum height) where the contact roller 61 is at a distance D from the lower surface 41 of the running rail 4, as shown in Figure 5(B); or a third state S3 (the position in which the lifting mechanism 63 lowers the contact roller 61 to its maximum height) as shown in Figure 5(C). The distance D is set based on the allowable amount of lift of the running roller 51.

[0043] The main controller 35 controls the lifting mechanism 63 to enter the first state S1 when the transport vehicle 6 transfers an item 10 to the mounting section 9. More specifically, the main controller 35 controls the lifting mechanism 63 to enter the first state S1 when the transport vehicle 6 transfers an item 10 to a mounting section 9 located to the lower right or lower left of the running rail 4, rather than to a mounting section 9 located directly below the running rail 4. Specifically, when the transport vehicle 6 transfers an item 10 to a mounting section 9 located to the lower left of the running rail 4 when viewed from the front in the direction of travel of the transport vehicle 6, the main controller 35 brings the contact roller 61 provided in the right tilt suppression mechanism 60B shown in Figure 4 into contact with the lower right surface 41, and when the transport vehicle 6 transfers an item 10 to a mounting section 9 located to the lower right of the running rail 4, the contact roller 61 provided in the left tilt suppression mechanism 60A shown in Figure 4 into contact with the lower left surface 41.

[0044] The main controller 35 controls the lifting mechanism 63 to enter the second state S2 when the transport vehicle 6 is traveling through at least the curved section 4C. Specifically, when the transport vehicle 6 is traveling through the curved section, the main controller 35 brings the contact roller 61 of the left tilt suppression mechanism 60A into contact with the left lower surface 41 when the left lower surface 41 in Figure 4 is located on the outside of the curve, and brings the contact roller 61 of the right tilt suppression mechanism 60B into contact with the right lower surface 41 when the right lower surface 41 in Figure 4 is located on the outside of the curve.

[0045] The main controller 35 controls the lifting mechanism 63 to enter the third state S3, except when transferring the vehicle or traveling through the curved section 4C, for example.

[0046] The lifting mechanism 63 has two optical sensors 66A and 66B. Each of the optical sensors 66A and 66B consists of, for example, a light-emitting part and a light-receiving part, and detects whether or not the light-receiving part receives light from the light-emitting part. As shown in Figure 6(C), the moving block 64E is fitted with a shielding plate 67 that can pass between the light-emitting part and the light-receiving part of the two optical sensors 66A and 66B, which are arranged side by side in the X-axis direction. The two optical sensors 66A and 66B are arranged such that optical sensor 66A is not detected by the shielding plate 67 in the first state S1, both optical sensors 66A and 66B are not detected by the shielding plate 67 in the second state S2, and optical sensor 66B is not detected by the shielding plate 67 in the third state S3. The main unit controller 35 switches the state of the contact roller 61 based on the detection results of the two optical sensors 66A and 66B.

[0047] Furthermore, when viewing the pair of side sections 42, 42 constituting the running rail 4 from a plan view, the outer side of the curve in the running rail 4 refers to the side section 42 with a larger curve radius (smaller curvature), and the inner side of the curve in the running rail 4 refers to the side section 42 with a smaller curve radius (larger curvature). The outer portion of the curve in the running rail 4 refers to the portion on the side section 42 where the curve radius is larger than the center line in the width direction, and the inner portion of the curve in the running rail 4 refers to the portion on the side section 42 where the curve radius is smaller than the center line in the width direction. In addition, in the lower section 41, side section 42 and upper section 43, the surface in contact with the internal space S is called the inner surface, and the surface opposite to the inner surface, i.e., the surface in contact with the external space, is called the outer surface.

[0048] The effects and advantages of the overhead transport vehicle system 1 of the above embodiment will now be explained. As shown in Figure 2, in a transport vehicle 6 configured such that the main body 7 is suspended from the running section 50, the main body 7 tilts due to centrifugal force when traveling through the curved section 4C, and the outer curved portion of the main body 7 approaches the running rail 4. In the transport vehicle 6 of the above embodiment, a contact roller 61 is provided on the upper surface of the main body 7 that contacts the outer curved portion of the running rail 4 from below in the curved section 4C. As a result, when the outer curved portion of the main body 7 tries to approach the running rail 4, the contact roller 61 contacts the outer curved portion of the running rail 4, and the reaction force at that time restricts the outer curved portion of the main body 7 from approaching the running rail 4. As a result, tilting of the main body 7, and consequently tilting of the running section 50 that suspends and supports the main body 7, is suppressed, and the amount of lift of the running roller 51 when the running section 50 travels through the curved section 4C can be suppressed.

[0049] In the transport vehicle 6 of the above embodiment, in the curved section 4C, the contact roller 61 contacts one of the pair of lower surfaces 41, 41, which is located on the outside of the curve. As a result, the reaction force when the contact roller 61 contacts one of the lower surfaces 41 restricts the outer part of the main body 7 from approaching the running rail 4 (lower surface 41).

[0050] The transport vehicle 6 of the above embodiment is equipped with a lifting mechanism 63 that raises and lowers the contact roller 61 in the vertical direction. This ensures that when it is desired to bring the contact roller 61 into contact with the running rail 4, the contact roller 61 can be reliably brought into contact with the running rail 4, and when it is desired to move the contact roller 61 away from the running rail 4, the contact roller 61 can be reliably moved away from the running rail 4.

[0051] In the transport vehicle 6 of the above embodiment, a trapezoidal screw 64C is used in part of the linear motion mechanism 64 that constitutes the lifting mechanism 63. Therefore, it is possible to counteract the reaction force when the contact roller 61 contacts the running rail 4 with a simple configuration, without employing complex mechanisms such as a brake mechanism.

[0052] In the transport vehicle 6 of the above embodiment, the main unit controller 35 controls the lifting mechanism 63 so that the contact roller 61 contacts the running rail 4 when at least the running section 50 is traveling through the curved section 4C. This makes it possible to more reliably bring the contact roller 61 into contact with the outer curve portion of the running rail 4 in the curved section 4C.

[0053] In the transport vehicle 6 of the above embodiment, the contact roller 61 is rotatably mounted, and its orientation is swingable. This allows the orientation of the contact roller 61 to be changed to align with the direction of travel of the travel unit 50, so that the contact roller 61 rotates smoothly when the transport vehicle 6 is in motion. This prevents the rotating part 61A constituting the contact roller 61 from sliding on the travel rail 4 and causing wear on the contact roller 61 due to the travel direction of the travel unit 50 not matching the orientation of the contact roller 61.

[0054] In the transport vehicle 6 of the above embodiment, the contact roller 61 is located in the center of the main body 7 in the direction of travel of the travel section 50. Therefore, even if the direction of the contact roller 61 is not oscillating, there is a high probability that the direction of travel of the travel section 50 and the direction of the contact roller 61 will coincide in the curved section 4C. This prevents the rotating part 61A of the contact roller 61 from sliding on the travel rail 4 due to the direction of travel of the travel section 50 and the direction of the contact roller 61 not coinciding, thus preventing wear of the rotating part 61A of the contact roller 61.

[0055] In the transport vehicle 6 of the above embodiment, the main unit controller 35 controls the lifting mechanism 63 so that the transport vehicle 6 enters the first state S1 when transferring an item 10 to the loading section 9. This prevents the main unit 7 from tilting to the left when transferring an item 10 to the loading section 9 located to the lower left of the travel rail 4, when viewed from the front in the direction of travel of the transport vehicle 6. It also prevents the main unit 7 from tilting to the right when transferring an item 10 to the loading section 9 located to the lower right of the travel rail 4.

[0056] Although one embodiment has been described above, one aspect of the present invention is not limited to the above embodiment. Various modifications are possible without departing from the spirit of the invention.

[0057] In the tilt suppression mechanism 60 of the above embodiment, the position of the contact roller 61 is lowered by moving the movable block 64E to the left, and the position of the contact roller 61 is raised by moving the movable block 64E to the right, as an example, but the mechanism is not limited to this. For example, as shown in Figures 8(A) to 8(C), the tilt suppression mechanism 60 may be configured such that the position of the contact roller 61 is raised by moving the movable block 64E to the left, and the position of the contact roller 61 is lowered by moving the movable block 64E to the right. The explanation of each part constituting the tilt suppression mechanism 60 is omitted.

[0058] Even with such a modified tilt suppression mechanism 60, the main unit controller 35 controls the lifting mechanism 63 so that, at least when the running section 50 is running through the curved section 4C, the contact roller 61 comes into contact with the running rail 4, as shown in Figure 8(B). This ensures that the contact roller 61 comes into contact with the outer curve portion of the running rail 4 in the curved section 4C.

[0059] In the above embodiments and modifications, examples were given in which a lifting mechanism 63 for raising and lowering the contact roller 61 is provided. However, for example, the lifting mechanism 63 may not be provided. In this case, for example, as shown in Figure 5(B), the contact roller 61 may be positioned at a distance D from the lower surface 41 of the running rail 4.

[0060] In the above embodiments and modifications, a trapezoidal screw 64C and a movable block 64E that screws onto the trapezoidal screw 64C were used as examples of the linear motion mechanism 64 provided in the tilt suppression mechanism 60. However, other mechanisms such as a ball screw, a linear guide, or a rack and pinion may also be used.

[0061] In the above embodiments and modifications, the linear motion mechanism 64 of the tilt suppression mechanism 60 is controlled when transferring the article 10 from the main body 7 to the mounting section 9 to achieve the state shown in Figure 5(A) or Figure 8(A), for example. However, such control is not necessarily required.

[0062] One aspect of the present invention can be described as follows: [1] An overhead transport vehicle having a running section equipped with running wheels that roll on a running rail, and a main body section that is supported by the running section via a suspension section and holds the object to be transported, An overhead transport vehicle, wherein the upper surface of the main body facing the running rail in the vertical direction is provided with a contact roller that contacts the outer curve portion of the running rail in a curved section from below. [2] The aforementioned running rail is The slit portion on which the suspension portion can move when the traveling section is in motion, The portion on which the aforementioned running wheel rolls includes a pair of rolling parts arranged opposite each other across the slit portion in a width direction perpendicular to both the vertical direction and the running direction of the running portion, The overhead transport vehicle according to [1], wherein in the curved section, the contact roller is provided to contact one of the pair of rolling parts that is located on the outside of the curve. [3] The overhead transport vehicle according to [1] or [2], further comprising a lifting mechanism for raising and lowering the contact roller in the vertical direction. [4] The overhead transport vehicle described in [3] includes a trapezoidal screw as part of the linear motion mechanism that constitutes the lifting mechanism. [5] The overhead transport vehicle according to [3] or [4], further comprising a control unit that controls the lifting mechanism so that the contact rollers contact the running rails when the running section is traveling through the curved section. [6] The overhead transport vehicle according to any one of [1] to [5], wherein the contact roller is rotatably mounted, and the orientation of the contact roller is such that it can swing with respect to a direction perpendicular to the axis of rotation when viewed from the vertical. [7] The contact roller is provided in the central part of the main body in the direction of travel of the traveling section, an overhead transport vehicle according to any one of [1] to [5]. [Explanation of Symbols]

[0063] 4...Travel rail, 4C...Curved section, 6...Transport vehicle (overhead transport vehicle), 7...Main unit, 10...Item, 35...Main unit controller (control unit), 50...Travel unit, 51...Travel roller, 60 (60A, 60B)...Tilt suppression mechanism, 61...Contact roller, 63...Lifting mechanism, 64...Linear motion mechanism, 64C...Trapezoidal screw, 65...Oscillating mechanism, G...Slit section.

Claims

1. An overhead transport vehicle having a running section equipped with running wheels that roll on a running rail, and a main body section that is supported by the running section via a suspension section and holds the object to be transported, On the upper surface of the main body facing the running rail in the vertical direction, a contact roller is provided that contacts the outer curve portion of the running rail in a curved section from below. The aforementioned running rail is The slit portion on which the suspension portion can move when the traveling section is in motion, The portion on which the aforementioned running wheel rolls includes a pair of rolling parts arranged opposite each other across the slit portion in a width direction perpendicular to both the vertical direction and the running direction of the running portion, In the curved section, the contact roller is provided to contact one of the pair of rolling parts, which is located on the outside of the curve. The overhead transport vehicle is equipped with a lifting mechanism that raises and lowers the contact rollers in the vertical direction.

2. The overhead transport vehicle according to claim 1, wherein a trapezoidal screw is included as part of the linear motion mechanism constituting the lifting mechanism.

3. The overhead transport vehicle according to claim 1 or 2, further comprising a control unit that controls the lifting mechanism so that the contact rollers contact the running rails when the running section is traveling through the curved section.

4. An overhead transport vehicle having a running section equipped with running wheels that roll on a running rail, and a main body section that is supported by the running section via a suspension section and holds an object to be transported, On the upper surface of the main body facing the running rail in the vertical direction, a contact roller is provided that contacts the outer curve portion of the running rail in a curved section from below. The overhead transport vehicle is configured such that the contact roller is rotatably mounted, and the orientation of the contact roller is such that it can swing in a direction perpendicular to the axis of rotation when viewed from the vertical.

5. The overhead transport vehicle according to claim 1 or 2, wherein the contact roller is provided in the central part of the main body in the direction of travel of the traveling section.

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