Overhead transport vehicle

Abstract

This overhead transport vehicle is configured so that a body part, which holds a transport object, is supported in a suspended state by a travelling cart. The overhead transport vehicle comprises a mass damper that is mounted on the travelling cart and that includes a mass body which can freely move relative to the travelling cart.

Description

Technical Field

[0001] One aspect of the present invention relates to an overhead carrier vehicle.

Background Art

[0002] Patent Document 1 discloses an automated guided vehicle (floor conveyor) including a carriage, an automated guided vehicle body mounted on the carriage via a damper for vibration isolation, and a transfer device provided on the automated guided vehicle body. In the automated guided vehicle described in Patent Document 1, vibration of an article (a conveyed item) to be conveyed is suppressed by the damper for vibration isolation.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of an overhead carrier vehicle in which a main body portion that holds a conveyed item is suspended and supported by a traveling carriage, it is not possible to adopt a configuration in which the main body portion is mounted on the traveling carriage via a damper for vibration isolation as in the above-described automated guided vehicle. Therefore, in this case, it may be difficult to suppress vibration of the conveyed item.

[0005] Therefore, one aspect of the present invention aims to suppress vibration of a conveyed item in an overhead carrier vehicle in which a main body portion that holds a conveyed item is suspended and supported by a traveling carriage.

Means for Solving the Problems

[0006] (1) An overhead carrier vehicle according to one aspect of the present invention is an overhead carrier vehicle in which a main body portion that holds a conveyed item is suspended and supported by a traveling carriage, and includes a mass damper including a mass body mounted on the traveling carriage and movable relative to the traveling carriage.

[0007] In this overhead transport vehicle, vibrations of the trolley can be suppressed by mass dampers, and as a result, vibrations of the transported goods can be suppressed. In other words, in an overhead transport vehicle in which the main body that holds the transported goods is suspended and supported by the trolley, it is possible to suppress vibrations of the transported goods.

[0008] (2) In the overhead transport vehicle described in (1) above, the traveling carriage has a suspension shaft that suspends and supports the main body, and at least a part of the suspension shaft is configured to be hollow so that an internal space is formed, and the mass damper may have a first mass damper provided in the internal space of the suspension shaft. In this case, the first mass damper can be mounted on the traveling carriage by utilizing the suspension shaft of the traveling carriage.

[0009] (3) In the overhead transport vehicle described in (1) or (2) above, the trolley may have a trolley body and a plurality of running wheels that are rotatable relative to the trolley body and are attached so as not to change in height. In this case, while suppressing vibration of the transported goods, it is possible to maintain a constant height relationship between the running rail on which the overhead transport vehicle travels and the trolley body, for example, and to travel with stable propulsion even if the trolley is driven by a linear motor.

[0010] (4) The overhead transport vehicle described in any one of the above paragraphs (1) to (3) is an overhead transport vehicle that travels along a running rail, and the traveling carriage has a traveling drive unit that drives the traveling carriage by magnetic force generated between it and a plurality of magnetic plates arranged on the running rail, and the mass damper may have a second mass damper that includes a mass body that is movable in the direction of travel of the traveling carriage relative to the traveling carriage. In this case, vibrations specific to a linear motor-driven traveling carriage (vibrations caused by the pitch of the magnetic plates) can be suppressed by the second mass damper.

[0011] (5) In the overhead transport vehicle described in (2) above, the suspension shafts extend vertically, are arranged in pairs apart in the direction of travel of the trolley, and are connected to the main body so as to be rotatable around the axial direction of the suspension shafts. The first mass damper may include a weight as a mass body arranged in the internal space and movable in the vertical direction, and an elastic member that applies a vertical elastic force to the weight in the internal space. In this case, the first mass damper can be specifically mounted using the suspension shafts. Then, for example, vibrations that occur when the trolley passes over a step can be suppressed by the first mass damper. [Effects of the Invention]

[0012] According to one aspect of the present invention, in an overhead transport vehicle in which the main body that holds the transported object is suspended and supported on a traveling trolley, it is possible to suppress vibration of the transported object with a simple configuration. [Brief explanation of the drawing]

[0013] [Figure 1] Figure 1 is a side view of the overhead transport vehicle according to the first embodiment, viewed from the side. [Figure 2] Figure 2 is a side view showing a schematic configuration of a trolley according to the first embodiment. [Figure 3] Figure 3 is a perspective view of the main body according to the first embodiment, seen from diagonally above. [Figure 4] Figure 4 is a side cross-sectional view showing the first mass damper according to the first embodiment. [Figure 5] Figure 5 is a side view showing a schematic configuration of a trolley according to the second embodiment. [Figure 6] Figure 6(a) is a perspective view showing a third mass damper according to the second embodiment. Figure 6(b) is a cross-sectional view along the line VI-VI in Figure 6(a). [Figure 7] Figure 7 is a side view showing a schematic configuration of a trolley according to the third embodiment. [Figure 8] Figure 8 is a plan view showing the fourth mass damper according to the third embodiment. [Modes for carrying out the invention]

[0014] Hereinafter, the ceiling transfer vehicle according to the embodiment will be described with reference to the drawings. The same reference numerals are given to the same elements, and redundant descriptions are omitted.

[0015] [First Embodiment] The ceiling transfer vehicle 1 shown in FIG. 1 travels along a traveling rail R provided at a position higher than the floor surface, such as the ceiling of a clean room. The ceiling transfer vehicle 1 conveys a conveyed object 90, for example, between a storage facility and a predetermined load port. Examples of the conveyed object 90 include containers such as a FOUP (Front Opening Unified Pod) that stores a plurality of semiconductor wafers and a reticle pod that stores a glass substrate, and general parts. The above containers have flanges 98 held by the ceiling transfer vehicle 1.

[0016] In the following description, for the sake of convenience of explanation, the X-axis direction in FIG. 1 is defined as the front-rear direction (traveling direction) of the ceiling transfer vehicle 1. The Z-axis direction in FIG. 1 is defined as the vertical direction (vertical direction) of the ceiling transfer vehicle 1. The Y-axis direction in FIG. 1 is defined as the left-right direction or the width direction of the ceiling transfer vehicle 1. The X-axis direction, the Y-axis direction, and the Z-axis direction are perpendicular to each other.

[0017] As shown in FIGS. 1 and 2, the ceiling transfer vehicle 1 includes a traveling carriage 2 and a main body 3. The traveling carriage 2 moves the ceiling transfer vehicle 1 along a traveling rail (track) R. The traveling carriage 2 is disposed within the traveling rail R. The traveling carriage 2 has a front traveling body 2A and a rear traveling body 2B as the carriage main body. A connecting portion 2D provided on the front traveling body 2A and a connecting portion 2D provided on the rear traveling body 2B are rotatably connected by a connecting shaft 2E. Each of the front traveling body 2A and the rear traveling body 2B is provided with a traveling wheel 2C and a traveling drive unit 2M.

[0018] The traveling wheels 2C are rotatable with respect to the front traveling body 2A and the rear traveling body 2B and are attached so that their positions in the height direction do not fluctuate (in other words, without intervening a suspension or the like). The traveling drive unit 2M is an LDM (Linear DC Motor) that drives (accelerates or brakes) the ceiling carrier 1 by the magnetic force generated between it and a magnetic plate disposed on the upper surface of the traveling rail R. Further, the traveling bogie 2 has a suspension shaft 2F that suspends and supports the main body 3.

[0019] The suspension shaft 2F extends downward along the vertical direction at the lower part of the traveling bogie 2. The suspension shafts 2F are arranged in a pair apart in the traveling direction (hereinafter, also simply referred to as the "traveling direction") of the traveling bogie 2. The suspension shaft 2F is a shaft body having a cylindrical outer shape. A part of the suspension shaft 2F is configured to be hollow so that an internal space 2G is formed. The internal space 2G is a cylindrical space with the vertical direction as the axial direction.

[0020] The main body 3 holds the conveyed object 90. The main body 3 is suspended and supported by the traveling bogie 2. More specifically, the main body 3 is suspended and supported by the traveling bogie 2 by connecting the pair of suspension shafts 2F, 2F of the traveling bogie 2 to a vibration isolation unit 20 provided on the main body frame 4 of the main body 3. The main body 3 includes a main body frame 4, a horizontal drive unit 5, a rotation drive unit 6, a lifting drive unit 7, a lifting unit 10, a pair of covers 8, and a controller 40.

[0021] The main body frame 4 is a frame that constitutes the upper part of the main body 3. The horizontal drive unit 5 is fixed to the lower part of the main body frame 4. The horizontal drive unit 5 moves the rotation drive unit 6, the lifting drive unit 7, and the lifting unit 10 in a direction (left - right direction) orthogonal to the extending direction of the traveling rail R in the horizontal plane. The rotation drive unit 6 rotates the lifting drive unit 7 and the lifting unit 10 in the horizontal plane. The lifting drive unit 7 raises and lowers the lifting unit 10 by winding and unwinding a suspension member 9 such as four belts. The lifting unit 10 is provided so as to be able to be raised and lowered by the lifting drive unit 7. The lifting unit 10 is raised and lowered by the suspension member 9 with respect to the horizontal drive unit 5, the rotation drive unit 6, and the lifting drive unit 7. The lifting unit 10 has a holding device 11 that grips the conveyed object 90.

[0022] The holding device 11 holds the transported object 90. The holding device 11 includes a pair of L-shaped arms 12, claw portions 13 fixed to each arm 12, and an opening / closing mechanism 15 that opens and closes the pair of arms 12. The opening / closing mechanism 15 moves the pair of arms 12 toward each other and toward each other. The pair of arms 12 move forward and backward in the direction of the opening / closing mechanism 15. This causes the pair of claw portions 13 fixed to the arms 12 to open and close.

[0023] The pair of covers 8 are positioned at the front and rear in the direction of travel, covering the horizontal drive unit 5, the rotary drive unit 6, the lifting drive unit 7, the lifting unit 10, and the holding device 11. When the lifting unit 10 is raised to its upper limit, the pair of covers 8 form a space below the holding device 11 where the conveyed object 90 is housed.

[0024] The controller 40 is an electronic control unit consisting of a CPU (Central Processing Unit), ROM (Read Only Memory), and RAM (Random Access Memory), etc. The controller 40 controls various operations in the overhead transport vehicle 1. Specifically, the controller 40 controls the traveling carriage 2, the horizontal drive unit 5, the rotary drive unit 6, and the lifting drive unit 7. The controller 40 can be configured as software, for example, in which a program stored in ROM is loaded onto RAM and executed by the CPU.

[0025] As shown in Figures 2, 3, and 4, the vibration isolation unit 20 comprises a base portion 23 attached to and suspended from the suspension shaft 2F of the trolley 2, and a pair of support portions 21 that support the horizontal axis 28 of the base portion 23 on the upper surface 4a of the main frame 4 via rubber bushings or the like. The base portion 23 is a member that extends in the front-rear direction. The base portion 23 has an insertion hole 23a through which the suspension shaft 2F can be inserted. The insertion hole 23a is formed at both ends of the base portion 23 in the front-rear direction. The inner circumferential surface of the insertion hole 23a is provided with a bearing 23b that supports the suspension shaft 2F so as to be rotatable around an axis along the extending direction of the suspension shaft 2F. As a result, the suspension shaft 2F is connected to the main body portion 3 so as to be rotatable around the axial direction of the suspension shaft 2F. In other words, the suspension shaft 2F is a horizontal pivot axis that can pivot horizontally relative to the main body portion 3. The support parts 21, 21 are fixed to the upper surface 4a of the main frame 4.

[0026] The overhead transport vehicle 1 of this embodiment is equipped with a first mass damper 50 and a second mass damper 60. The first mass damper 50 and the second mass damper 60 are mounted on a traveling carriage 2. The first mass damper 50 and the second mass damper 60 are mass dampers that include a weight (mass body) L that is movable relative to the traveling carriage 2. A mass damper is also called a dynamic vibration absorber.

[0027] The first mass damper 50 is built into the suspension shaft 2F. The first mass damper 50 is provided in the internal space 2G of each of the pair of suspension shafts 2F. The first mass damper 50 has a first weight 51 located in the internal space 2G, and first springs 52 located above and below the first weight 51 in the internal space 2G.

[0028] The first weight 51 is provided to be movable in the vertical direction. The first weight 51 is formed in a cylindrical shape corresponding to the internal space 2G. The first weight 51 is slidable in the vertical direction with respect to the inner circumferential surface constituting the internal space 2G. The first spring 52 is an elastic member that applies an elastic force in the vertical direction to the first weight 51 in the internal space 2G. The first spring 52 is, for example, a coil spring with the vertical direction as its axial direction.

[0029] A spring washer 53 is attached to the lower side of the first spring 52, which is positioned below the first weight 51. The upper side of the first spring 52, which is positioned below the first weight 51, contacts the lower surface of the first weight 51. The lower side of the first spring 52, which is positioned above the first weight 51, contacts the upper surface of the first weight 51. A spring washer 54 is attached to the upper side of the first spring 52, which is positioned above the first weight 51. The movement of the spring washer 54 is restricted by a snap ring 55 to prevent it from coming out upward. The spring washer 54 seals the internal space 2G.

[0030] As shown in Figure 2, the second mass damper 60 is provided around the drive unit 2M in both the front travel body 2A and the rear travel body 2B. Here, the second mass damper 60 is positioned directly below the drive unit 2M. The second mass damper 60 has a case 61, a second weight 62 disposed inside the case 61, and a second spring 63 disposed inside the case 61. The second weight 62 is a mass body that can move in the direction of travel. The second spring 63 is an elastic member that applies an elastic force in the direction of travel to the second weight 62. The second spring 63 is, for example, a coil spring with the direction of travel as its axial direction. The second spring 63 is positioned inside the case 61 on one side and the other side of the second weight 62 in the direction of travel.

[0031] In the overhead transport vehicle 1 described above, the vibration of the traveling carriage 2 can be suppressed by the first mass damper 50 and the second mass damper 60, and as a result, the vibration of the transported object 90 can be suppressed. In other words, in the overhead transport vehicle 1 in which the main body 3 that holds the transported object 90 is suspended and supported by the traveling carriage 2, it is possible to suppress the vibration of the transported object 90 with a simple configuration. As a result, for example, in the overhead transport vehicle 1, when an impact occurs due to the traveling wheels 2C crossing a joint or step (step at the transfer section) of the traveling rail R, the weights L elastically supported by the first mass damper 50 and the second mass damper 60 move with a delay due to inertial force, and the vibration after the impact (vibration due to rebound) can be reduced. In addition, vibrations caused by factors other than joints and steps can also be reduced.

[0032] In the overhead transport vehicle 1, the trolley 2 has a suspension shaft 2F that suspends and supports the main body 3. At least a portion of the suspension shaft 2F is configured to be hollow so that an internal space 2G is formed. The first mass damper 50 is provided in the internal space 2G. In this case, the first mass damper 50 can be mounted on the trolley 2 using the suspension shaft 2F of the trolley 2 without requiring any changes to the structure of the trolley 2 itself.

[0033] In the overhead transport vehicle 1, the trolley 2 has a front trolley 2A and a rear trolley 2B, and a plurality of running wheels 2C that are rotatable relative to the front trolley 2A and the rear trolley 2B and are mounted so as not to change their position in the height direction. In the overhead transport vehicle 1, it is difficult to connect the running wheels 2C to the front trolley 2A and the rear trolley 2B with an elastic body (such as a suspension) as in an automobile, because this would be a major factor in the fluctuation of the distance between the LDM and the magnetic plate. Therefore, the running wheels 2C to the front trolley 2A and the rear trolley 2B are rigidly connected. In this case, while suppressing vibrations of the transported object 90, it is possible to maintain a constant height-direction relationship between, for example, the running rail R and the front trolley 2A and the rear trolley 2B, and to travel with stable propulsion even if the trolley 2 is driven by a linear motor.

[0034] The overhead transport vehicle 1 travels along the travel rail R. The traveling carriage 2 has a travel drive unit 2M which is an LDM. The traveling carriage 2 has a second mass damper 60 which includes a second weight 62 that is movable in the direction of travel relative to the traveling carriage 2. In this case, vibrations specific to linear motor drives that repeatedly switch between attraction and repulsion (vibrations caused by the pitch of the magnetic plate) can be effectively suppressed by the second mass damper 60.

[0035] In the overhead transport vehicle 1, the suspension shafts 2F extend vertically and are arranged in pairs, separated in the direction of travel, and are connected to the main body 3 by a vibration isolation unit 20 so as to be rotatable around the axial direction of the suspension shafts 2F. The first mass damper 50 includes a first weight 51 as a mass body located in the internal space 2G and movable in the vertical direction, and a first spring 52 that applies an elastic force in the vertical direction to the first weight 51 in the internal space 2G. In this case, the first mass damper 50 can be specifically mounted using the suspension shafts 2F. Then, for example, vibrations that occur when the traveling trolley 2 passes over a step can be effectively suppressed by the first mass damper 50.

[0036] [Second Embodiment] A second embodiment will now be described. In the description of the second embodiment, the differences from the first embodiment will be explained, and redundant explanations will be omitted.

[0037] As shown in Figures 5, 6(a), and 6(b), the overhead transport vehicle 100 of this embodiment differs from the first embodiment in that it further includes a third mass damper 70. The third mass damper 70 is provided inside the front cover 2K and the rear cover 2L of the traveling carriage 2, respectively. The third mass damper 70 has a case 71, a third weight 72 disposed inside the case 71, and a third spring 73 disposed inside the case 71. The third weight 72 is a mass body that can move in the direction of travel. The third spring 73 is an elastic member that applies an elastic force in the direction of travel to the third weight 72. The third spring 73 is, for example, a coil spring with the direction of travel as its axial direction. The third spring 73 is disposed inside the case 71 on one side and the other side of the third weight 72 in the direction of travel.

[0038] In the example shown in Figures 6(a) and 6(b), a circular case 71 with an axial orientation in the front-rear direction is fixed to the walls of the front cover 2K and the rear cover 2L with bolts 75. Inside the case 71, there is a main shaft 76 extending in the front-rear direction from the axial center of the case 71, and three second shafts 78 arranged at equal intervals in the circumferential direction around the main shaft 76 and extending in the front-rear direction. The bolts 75 are inserted through the inside of the main shaft 76.

[0039] The third weight 72 is formed in a cylindrical shape with its axial direction in the front-to-back direction. The third weight 72 is located inside the case 71. The third weight 72 has a through hole 79 through which the main shaft 76 passes, and through holes (not shown) through which the three second shafts 78 pass. A third spring 73 is provided inside the case 71, both in front of and behind the third weight 72, around each of the three second shafts 78.

[0040] In addition, the overhead transport vehicle 100, like the overhead transport vehicle 1 described above, is able to suppress vibrations of the transported object 90 and achieve other effects. Furthermore, the third mass damper 70 makes it possible to suppress vibrations specific to linear motor drive.

[0041] [Third Embodiment] A third embodiment will now be described. In the description of the third embodiment, the differences from the first embodiment will be explained, and redundant explanations will be omitted.

[0042] As shown in Figures 7 and 8, the overhead transport vehicle 200 of this embodiment differs from the first embodiment in that it further includes a fourth mass damper 80. The fourth mass damper 80 is provided to be located inside the vibration isolation unit 20.

[0043] The fourth mass damper 80 is positioned in the central space 23H in the front-rear direction of the base portion 23 of the vibration isolation unit 20. The fourth mass damper 80 includes a pair of shafts 81 extending along the direction of travel and aligned in the left-right direction, a fourth weight 82 movable along the pair of shafts 81, a holder 83 holding one end and the other end of the pair of shafts 81, and a fourth spring 84 provided around each shaft 81 between the fourth weight 82 and the holder 83. The fourth weight 82 is a mass body movable in the direction of travel. The holder 83 is fixed to the upper surface 4a of the main frame 4. The fourth spring 84 is an elastic member that applies an elastic force in the direction of travel to the fourth weight 82. The fourth spring 84 is, for example, a coil spring with the direction of travel as its axial direction.

[0044] In addition, the overhead transport vehicle 200, like the overhead transport vehicle 1, achieves effects such as suppressing vibrations of the transported object 90. Furthermore, the fourth mass damper 80 makes it possible to suppress vibrations of the main body 3 during travel.

[0045] Although embodiments have been described above, one aspect of the present invention is not limited to the above embodiments. Various modifications are possible without departing from the spirit of one aspect of the invention.

[0046] In the above embodiment, the vibration reduction may be appropriately controlled by changing the orientation and mass of each of the first to fourth mass dampers 50, 60, 70, and 80 according to the purpose or specifications. In the above embodiment, the weight, material, and shape of the weight L are not particularly limited. In the above embodiment, the type and elastic force of the first to fourth springs 52, 63, 73, and 84 are not particularly limited.

[0047] In the above embodiment, a different type or form of mass damper may be used instead of at least one of the first to fourth mass dampers 50, 60, 70, and 80. In the above embodiment, the placement position of the mass damper is not particularly limited and it is sufficient that it is mounted on the trolley 2. For example, in the above embodiment, separate mass dampers may be provided on the front and rear covers 8 of the trolley 2 in the direction of travel. In the above embodiment, the mass damper may be configured to contain, for example, particles (mass bodies) such as sand that are movable in space. In the above embodiment, an example was described in which the trolley body of the trolley 2 has a front running body 2A and a rear running body 2B that are rotatable relative to each other, but the trolley body may be formed from a single running body.

[0048] The components in the above embodiments and modifications are not limited to the materials and shapes described above, and various materials and shapes can be applied. Each component in the above embodiments or modifications can be arbitrarily applied to each component in other embodiments or modifications. Parts of each component in the above embodiments or modifications can be omitted as appropriate without departing from the spirit of one aspect of the present invention. [Explanation of Symbols]

[0049] 1...Overhead transport vehicle, 2...Traveling trolley, 2A...Front traveling body (truck body), 2B...Rear traveling body (truck body), 2C...Traveling wheels, 2F...Suspension axle, 2G...Internal space, 2M...Traveling drive unit, 3...Main body, 50...First mass damper (mass damper), 51...First weight, 52...First spring (elastic member), 60...Second mass damper (mass damper), 62...Second weight, 63...Second spring (elastic member), 70...Third mass damper (mass damper), 72...Third weight, 73...Third spring (elastic member), 90...Conveyed object, L...Weight (mass body), R...Traveling rail.

Claims

1. An overhead transport vehicle in which the main body that holds the transported objects is suspended and supported from a traveling trolley, The trolley is mounted on the aforementioned trolley and includes a mass damper that is movable relative to the trolley, The aforementioned trolley has a suspension shaft that suspends and supports the main body, At least a portion of the suspension shaft is configured to be hollow so that an internal space is formed, The overhead transport vehicle has a first mass damper provided in the internal space of the suspension shaft.

2. The overhead transport vehicle according to claim 1, wherein the traveling trolley comprises a trolley body and a plurality of traveling wheels mounted to the trolley body so as to be rotatable and so as not to change their position in the height direction.

3. An overhead transport vehicle that travels along a rail, The aforementioned trolley has a traction drive unit that drives the trolley by magnetic force generated between it and a magnetic plate arranged on the trolley rail, The overhead transport vehicle according to claim 2, wherein the mass damper includes a second mass damper that is movable relative to the traveling trolley in the direction of travel of the traveling trolley.

4. The suspension shafts extend vertically, are arranged in pairs apart in the direction of travel of the trolley, and are connected to the main body so as to be rotatable around the axial direction of the suspension shafts. The overhead transport vehicle according to claim 1, wherein the first mass damper includes a weight as the mass body disposed in the internal space and movable in the vertical direction, and an elastic member that applies a vertical elastic force to the weight in the internal space.

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