robot

Abstract

A robot capable of flexibly using the maximum stroke length of a shaft capable of lifting is provided. The robot includes a base having a housing; a first arm capable of rotating about a first shaft with respect to the base; a second arm capable of rotating about a second shaft with respect to the first arm; a first motor provided in the housing to generate power for rotating the first arm with respect to the base; a speed reducer provided in the housing to reduce the rotation of the first motor; and a second motor to generate power for rotating the second arm with respect to the first arm, the housing having a bottom plate portion provided with a first through-hole, a portion of the speed reducer being disposed in the first through-hole, the first arm having a first arm base extending in a direction orthogonal to the first shaft, and a housing portion protruding downward from the first arm base to house the second motor and be separated from the second arm.

Description

Technical Field

[0001] This invention relates to robots. Background Technology

[0002] Patent Document 1 discloses a ceiling-mounted robot. The robot includes: a base; a first arm disposed below the base and rotatable relative to the base; a second arm disposed below the first arm and rotatable relative to the first arm; and a shaft disposed on the second arm, rotatable and capable of lifting. In known ceiling-mounted robots, to prevent interference between the first arm and the base, and between the first arm and supports such as the ceiling, when the first arm rotates relative to the base, the first arm is arranged separately below the base.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2016-140921

[0004] However, the greater the distance between the first arm and the base, the lower the second arm is positioned, and the closer the lower end of the shaft on the second arm is to the workpiece, floor, or other object positioned below the shaft. As a result, the shaft can only lift a length shorter than its maximum travel length, thus failing to fully utilize the maximum travel length of the shaft. Summary of the Invention

[0005] The robot involved in the application examples of this invention has the following features: The base has a shell; The first arm is located below the base and is capable of rotating about a first axis relative to the base; The second arm is located below the first arm and is capable of rotating about a second axis relative to the first arm, the second axis being parallel to the first axis; A shaft is provided at the end of the second arm and is capable of moving up and down along a third axis, which is parallel to the second axis; A first motor, disposed within the housing, generates power to rotate the first arm relative to the base; A speed reducer is installed inside the housing to reduce the rotation speed of the first motor and transmit the power to the first arm; A second motor generates power to rotate the second arm relative to the first arm; and The third motor generates the power to raise and lower the shaft. The housing has a bottom plate portion, and the bottom plate portion is provided with a first through hole extending along the first axis. A portion of the speed reducer is disposed within the first through hole. The first arm has: a first arm base extending in a direction orthogonal to the first axis; and a receiving portion protruding downward from the first arm base to receive the second motor and being separated from the second arm. Attached Figure Description

[0006] Figure 1 This is a side view showing a robot system equipped with a robot according to an embodiment of the present invention.

[0007] Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the base of the robot.

[0008] Figure 3 It is along Figure 1 A cross-sectional view along line III-III.

[0009] Figure 4 It is along Figure 1 A cross-sectional view along line IV-IV.

[0010] Figure 5 It is along Figure 1 A cross-sectional view of the VV line.

[0011] Figure 6 This is a side view showing the maximum travel length of the shaft.

[0012] Explanation of reference numerals in the attached figures

[0013] 1…Robot system, 10…Robot, 11…Base, 11a…House, 11i…Connector, 12…Robot arm, 12a…First arm, 12b…Second arm, 13…Working head, 13a…Spline nut, 13b…Ball screw nut, 13c…Shaft, 13d…End effector, 14…First drive unit, 15…Second drive unit, 16…Third drive unit, 17…Fourth drive unit, 30…Control device, 111…House body, 111a…Top plate, 111b…Side wall, 112…Bottom plate, 112d…Recess, 112h…First through hole, 121a…First arm base, 121b…Accommodation 121d…recess, 121h…second through hole, 122a…connecting part, 122b…housing, 123…second arm base, 124…cover, 124i…connector, 131…upper stop, 132…lower stop, 141…first motor, 142…belt drive, 142a…first pulley, 142b…second pulley, 142c…ring drive belt, 142h…threaded hole, 142s…set screw, 144a…first bearing, 144b…second bearing, 145…first support member, 146…second support member, 146a…first part, 146b…second part, 147…sleeve 151…Second motor, 152…Belt drive, 152a…Third pulley, 152b…Fourth pulley, 152c…Annular drive belt, 153…Reducer, 161…Third motor, 162…Transmission unit, 162a…Pulley, 162b…Pulley, 162c…Annular drive belt, 171…Fourth motor, 172…Transmission unit, 172a…Pulley, 172b…Pulley, 172c…Annular drive belt, 172d…Shaft assembly, 172e…Pulley, 172f…Pulley, 172g…Annular drive belt, 200…Reducer, 210…Input shaft, 210A…Contact part, 211…Main body, 212… Bearing, 213…inner ring, 214…outer ring, 215…rolling element, 216…retainer, 220…intermediate part, 221…cylindrical part, 221a…external gear, 222…outer peripheral part, 230…output shaft, 230A…contact part, 240…bearing, 241…inner ring, 242…outer ring, 243…rolling element, A1…first shaft, A2…second shaft, A3…third shaft, C1…curve, D1…first direction, D2…second direction, D3…third direction, G1…separation distance, H…distance, H1…maximum length, H2…maximum length, L0…total length, L1…length, S…maximum stroke length, T1…support body. Detailed Implementation

[0014] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be noted that the following description does not limit the technical scope or the meaning of the terms used in the claims. Furthermore, the dimensions in the drawings may be exaggerated for ease of explanation and differ from the actual proportions. In the embodiments of the present invention, unless specifically stated or limited, terms such as "connection" and "fixed" should be interpreted broadly. For example, "fixed" includes a fixed connection, a detachable connection, or an integral connection; it can be a mechanical or electrical connection, a direct connection, or an indirect connection via other components. Unless specifically limited, it can also refer to an internal connection between two elements or an interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in the embodiments of the present invention based on the specific circumstances.

[0015] The robot 10 according to the embodiments of the present invention will be described.

[0016] Figure 1 This is a side view showing a robot system 1 equipped with the robot 10 according to this embodiment. Figure 2 yes Figure 1 The diagram shows a cross-sectional view of the base 11 of the robot 10. Figure 3 It is along Figure 1 A cross-sectional view along line III-III. Figure 4 It is along Figure 1 A cross-sectional view along line IV-IV. Figure 5 It is along Figure 1 A cross-sectional view of the VV line. Figure 6 This is a side view showing the maximum stroke length S of shaft 13c. It should be noted that... Figure 2 In the image, elements of a portion of the robot 10 are shown from a side view. Additionally, in... Figure 3 The illustration of the retainer 216 of the bearing 212, which will be described later, is omitted.

[0017] Although details will be discussed later, as Figure 1 As shown, the base 11, first arm 12a, second arm 12b, shaft 13c, and end effector 13d of robot 10 are connected in this order. In the following, the side of base 11 will be referred to as the "base end side" or "base end portion" in these connection paths, and the opposite side will be referred to as the "end end side" or "end portion".

[0018] Furthermore, in each figure, the X-axis, Y-axis, and Z-axis are defined as three mutually orthogonal axes for the workspace of robot 10. Arrows are used to represent each axis, with the end of the arrow designated as the "+" side and the base of the arrow designated as the "-" side. In the following explanations, for example, "X-axis direction" includes both the positive and negative directions of the X-axis. The same applies to the Y-axis and Z-axis directions.

[0019] Furthermore, in each figure, the direction parallel to the lifting axis of the shaft 13c, i.e., the third axis A3, described later, is defined as the Z-axis direction. Additionally, in the Z-axis direction, the direction (Z-axis direction + side) near the end portion of the shaft 13c where the end effector 13d is mounted, close to the second arm 12b, is defined as "above," "upward direction," or "upward side," and its opposite direction (Z-axis direction - side) is defined as "below," "downward direction," or "downward side." Furthermore, movement of the shaft 13c towards the Z-axis direction + side is referred to as "rising," movement towards the Z-axis direction - side is referred to as "falling," and movement in the Z-axis direction is referred to as "lifting." Furthermore, the "upper end" of an object refers to the portion extending downward from the top of the object, and the "lower end" of an object refers to the portion extending upward from the bottom of the object, also encompassing a certain range. It should be noted that in this embodiment, the Z-axis direction is parallel to the vertical direction. However, the Z-axis direction does not necessarily need to be parallel to the vertical direction; it can also be inclined relative to the vertical direction.

[0020] Furthermore, in this specification, "parallel" refers not only to the case where two objects are strictly parallel, but also to the case where one object is tilted within ±10°, i.e., substantially parallel, even though the two objects are strictly parallel. Similarly, in this specification, "orthogonal" refers not only to the case where two objects are strictly orthogonal, but also to the case where one object is tilted within ±10°, i.e., substantially orthogonal, even though the two objects are strictly orthogonal.

[0021] If reference Figure 1 To give a general description, the robot system 1 involved in this embodiment includes a robot 10 and a control device 30 for controlling the drive of each part of the robot 10.

[0022] Robot 10 is a top-mounted horizontal articulated robot (SCARA robot). Robot 10 is used in various operations such as holding, conveying, assembling, processing, painting, and inspecting workpieces such as electronic components. However, the purpose and types of operations performed by robot 10 are not limited to those described above.

[0023] The robot 10 has a base 11, a robotic arm 12 disposed below the base 11, and a working head 13 disposed at the end of the robotic arm 12.

[0024] The base 11 is mounted on a support T1 located above the robot arm 12 in the vertical direction, on a ceiling, column, beam, or frame. The robot 10 hangs from the support T1. The base 11 has a box-shaped housing 11a. The housing 11a has a housing body 111 with a lower opening and a bottom plate 112 covering the lower opening of the housing body 111.

[0025] The housing body 111 has a top plate portion 111a parallel to the XY plane and a side wall portion 111b extending downward from the outer periphery of the top plate portion 111a. One or more connectors 11i are provided on the top plate portion 111a for connecting external devices such as equipment and control devices 30 installed on the robot 10. While not particularly limited, examples of equipment installed on the robot 10 include, for example, the first drive unit 14, the second drive unit 15, the third drive unit 16, the fourth drive unit 17, and the end effector 13d, which will be described later. Furthermore, while not particularly limited, the equipment installed on the robot 10 may include, for example, sensors such as angle sensors (not shown), inertial sensors, cameras, solenoid valves, and their power supply boards, control boards, and other electronic boards.

[0026] The device and connector 11i located on the robot 10 are connected by one or more linear components (not shown) passing through the base 11 and the robotic arm 12. Additionally, the connector 11i and external devices are connected by linear components passing through the outside of the robot 10.

[0027] Examples of linear components include wiring and flexible, hollow, elongated components. Examples of wiring include electrical wiring such as cables and optical wiring such as fiber optic cables. External devices transmit and receive signals with equipment installed on the robot 10 via wiring and connector 11i. Furthermore, fluids such as air circulate inside the hollow, elongated component, allowing external devices to supply fluid to equipment installed on the robot 10, such as the end effector 13d, or to draw fluid from the surrounding environment of that equipment. While not particularly limited, examples of hollow, elongated components include tubes, pipes, hoses, and ducts.

[0028] Connector 11i can be a connector capable of connecting electrical wiring, a connector capable of connecting optical wiring, or a connector capable of connecting long, hollow components. Furthermore, multiple linear components can be bundled together. Additionally, a linear component can branch into multiple branches midway. Furthermore, relay devices or relay connectors can be installed midway along the linear component.

[0029] The base plate 112 is a flat plate parallel to the XY plane. The base plate 112 is fixed to the lower end of the housing body 111 by screws or the like. Furthermore, when viewed from above, the outer periphery of the base plate 112 protrudes outward from the housing body 111. The upper surface of the outer periphery of the base plate 112 is in contact with the lower surface of the support body T1, and the outer periphery of the base plate 112 is fixed to the support body T1 by screws or the like.

[0030] The robotic arm 12 is located below the base 11. The robotic arm 12 has a first arm 12a disposed on the base 11 and a second arm 12b disposed on the first arm 12a.

[0031] The first arm 12a is located below the base 11. The base end of the first arm 12a is connected to the base 11 in a manner that allows it to rotate about a first axis A1. The first axis A1 is parallel to the Z-axis direction.

[0032] The first arm 12a has a first arm base 121a and a receiving portion 121b. The first arm base 121a extends in a direction orthogonal to the first axis A1, that is, in a direction parallel to the XY plane. Figure 4 As shown, the first arm base 121a is hollow, for example, a cuboid with rounded corners. The sidewalls of the first arm base 121a have rib structures. This improves the strength of the first arm base 121a.

[0033] like Figure 1 As shown, the receiving portion 121b accommodates the second motor 151 of the second drive unit 15 (described later) and protrudes downward from the first arm base 121a. Therefore, when the first arm 12a is rotated relative to the base 11, the receiving portion 121b and the base 11 do not interfere with each other. Therefore, compared to the case where the receiving portion 121b protrudes upward from the first arm base 121a, the first arm 12a can be brought closer to the base 11. It should be noted that in this specification, "the receiving portion 121b accommodates the second motor 151" means that most of the second motor 151 is accommodated in the receiving portion 121b, and a portion of the second motor 151 is allowed to protrude upward from the receiving portion 121b. In addition, the receiving portion 121b is separated from the second arm 12b. Therefore, it is possible to form a structure in which the first arm 12a and the second arm 12b do not interfere with each other when the receiving portion 121b protrudes downward from the first arm base 121a and the second arm 12b is rotated relative to the first arm 12a. The shape of the first arm 12a is not limited to the shape described above and illustrated.

[0034] The second arm 12b is located below the first arm 12a. The base of the second arm 12b is connected to the end of the first arm 12a in a manner that allows it to rotate about a second axis A2. The second axis A2 is parallel to the first axis A1.

[0035] The second arm 12b has: a connecting portion 122a extending along the second axis A2 and connected to the end portion of the first arm 12a in a manner rotatable about the second axis A2; and a housing 122b housing the third drive portion 16 and the fourth drive portion 17 described later, and having a working head 13. The housing 122b includes: a second arm base 123 connected to the lower end portion of the connecting portion 122a and extending in a direction orthogonal to the second axis A2; and a cover 124 disposed above the second arm base 123 and to the side of the connecting portion 122a, and detachably mounted to the second arm base 123.

[0036] In the following, the direction parallel to the first axis A1, the second axis A2, and the third axis A3 will be referred to as "first direction D1", the direction orthogonal to the first direction D1 and moving from the second axis A2 toward the third axis A3 will be referred to as "second direction D2", and the direction orthogonal to both the first direction D1 and the second direction D2 will be referred to as "third direction D3". Furthermore, the first direction D1 is parallel to the Z-axis. The second direction D2 and the third direction D3 are parallel to the XY plane and their orientation changes with the rotation of the second arm 12b. Additionally, arrows will be used to represent the directions D1, D2, and D3, with the end of the arrow designated as the "+ side" and the base of the arrow designated as the "- side".

[0037] The connecting portion 122a is hollow, for example, cylindrical. The length of the connecting portion 122a in the first direction D1 is set to a length such that when the second arm 12b is rotated with the shaft 13c in its most raised state, the shaft 13c does not contact the first arm 12a. Therefore, in this embodiment, the second arm 12b can rotate 360 ​​degrees relative to the first arm 12a.

[0038] The structure of the connecting portion 122a is not limited to the structures described above and illustrated. For example, the upper end of the connecting portion 122a may be fixed to the first arm base 121a, and the lower end of the connecting portion 122a may be connected to the base end of the second arm base 123 in a manner that allows rotation about the second axis A2. Alternatively, the connecting portion 122a may have: a first portion fixed to the first arm base 121a and extending along the first axis A1; and a second portion connected to the lower end of the first portion in a manner that allows rotation about the second axis A2, fixed to the second arm base 123, and extending along the first axis A1.

[0039] The second arm base 123 extends along the second direction D2. For example... Figure 5 As shown, the second arm base 123 is hollow, for example, a cuboid with rounded corners. The sidewalls of the second arm base 123 have rib structures. This improves the strength of the second arm base 123. The shape of the second arm base 123 is not limited to the shapes described above and illustrated.

[0040] In this embodiment, the first arm base 121a and the second arm base 123 are manufactured by extrusion molding. Specifically, the first arm base 121a and the second arm base 123 are manufactured by processing through holes, recesses, etc., on a molded article extruded using a molding die of the same shape and provided on their respective equipment, linear components, etc.

[0041] Therefore, the cross-sectional shape of the first arm base 121a, orthogonal to its long side direction, is constant along the long side direction of the first arm base 121a. Similarly, the cross-sectional shape of the second arm base 123, orthogonal to its long side direction, is constant along the long side direction of the second arm base 123 (second direction D2). Hereinafter, the cross-sectional shapes of each arm base 121a and 123 orthogonal to its long side direction will also be referred to as "cross-sectional shapes." Figure 4 as well as Figure 5 As shown, the cross-sectional shape of the first arm base 121a and the cross-sectional shape of the second arm base 123 are the same.

[0042] Here, "cross-sectional shape" means ignoring the shape of the cross-section of through holes, recesses, etc. Furthermore, "same cross-sectional shape" does not only mean that the two cross-sectional shapes are completely identical, but also includes cases where the two cross-sectional shapes are substantially the same to the extent that manufacturing tolerances are acceptable. Thus, in this embodiment, a common molding die is used when manufacturing the first arm base 121a and the second arm base 123 using extrusion molding. This allows for easy and efficient manufacturing of the robot 10 and reduces manufacturing costs. In particular, as in this embodiment, when the first arm base 121a and the second arm base 123 have complex shapes such as rib structures for reinforcement, it is particularly advantageous that two different types of complex molding dies are not required.

[0043] It should be noted that in this embodiment, the length of the first arm base 121a in the long side direction and the length of the second arm base 123 in the long side direction are the same. Alternatively, the lengths of the first arm base 121a and the second arm base 123 in the long side direction can be different by using different extrusion lengths during extrusion molding. Furthermore, the manufacturing method of the first arm base 121a and the second arm base 123 is not limited to extrusion molding using a common molding die. Additionally, the first arm base 121a may have portions with different cross-sectional shapes along the long side direction, and the second arm base 123 may also have portions with different cross-sectional shapes along the long side direction. Furthermore, all or part of the cross-sectional shape of the first arm base 121a may differ from the cross-sectional shape of the second arm base 123.

[0044] The shell 11a, first arm base 121a, receiving portion 121b, connecting portion 122a, and second arm base 123 of the base 11 are each made of rigid bodies. In this specification, "rigid body" means a body whose deformation is negligible under applied force; that is, a substantially rigid body. While not particularly limited, the materials used to construct the shell 11a, first arm base 121a, receiving portion 121b, connecting portion 122a, and second arm base 123 of the base 11 can include, for example, various metallic materials, various resin materials, various ceramic materials, and materials obtained by combining two or more of these. While not particularly limited to metallic materials, examples include iron, stainless steel, aluminum, copper, titanium, and alloys of two or more of these.

[0045] It should be noted that, as mentioned above, when the first arm substrate 121a and the second arm substrate 123 are manufactured by extrusion molding, although there are no particular limitations on the materials used to construct them, alloys containing aluminum, glass, carbon fiber, and composite materials thereof are preferred, for example. Similarly, although there are no particular limitations on the materials used to construct the housing 121b and the cover 124, for example, polyolefins such as polyethylene and polypropylene, polyesters such as polyethylene terephthalate, thermoplastic resins such as acrylic resins, and thermosetting resins such as epoxy resins and phenolic resins are preferred.

[0046] like Figure 1 As shown, the cover 124 is, for example, constructed from a sheet material shaped into a desired three-dimensional form. The cover 124 forms an internal space between itself and the second arm base 123 by being mounted on the second arm base 123.

[0047] like Figure 6 As shown, the maximum length H1 of the cover 124 in the first direction D1 is greater than the maximum length H2 of the receiving portion 121b in the first direction D1. Therefore, the receiving portion 121b can be positioned below the first arm base 121a, and the maximum length of the internal space of the cover 124 in the first direction D1 can be sufficiently ensured. Thus, the internal components such as the third motor 161, the transmission portion 162, and the fourth motor 171, which will be described later, can be accommodated within the cover 124.

[0048] The units of H1 and H2 are set to be the same. At this time, although there is no particular limitation, it is preferable that H2 / H1 is 0.15 or more and 0.97 or less, more preferably 0.3 or more and 0.9 or less. As a result, the balance between H1 and H2 becomes better, and the accommodating space of the accommodating part 121b and the internal space of the cover 124 can be adequately ensured as described above.

[0049] In addition, such as Figure 1As shown, one or more connectors 124i are provided on the upper surface of the cover 124. The connectors 124i are used to connect the linear components extending from the connectors 11i of the base 11 to the device provided on the outer surface of the second arm 12b or the shaft 13c. Although there is no particular limitation on the device provided on the outer surface of the second arm 12b or the shaft 13c, examples include end effectors 13d, sensors (not shown), cameras, solenoid valves, etc.

[0050] When viewed from the first direction D1, the receiving portion 121b of the first arm 12a is located further inward than the rotation track of the connector 124i when the second arm 12b is rotated. Therefore, when the second arm 12b is rotated relative to the first arm 12a, it is possible to prevent the connector 124i, which is provided on the upper surface of the cover 124, and the linear component connected to the connector 124i and exposed to the outside, from contacting the receiving portion 121b. As a result, the second arm 12b can rotate flexibly relative to the first arm 12a.

[0051] The cover 124 can be made of a rigid body, or of a flexible or elastic material that is slightly deformable when a force is applied, or of a material composed of combinations thereof. Although there are no particular limitations on the materials used to make the cover 124, the same materials as those exemplified in the housing 11a of the base 11 can be listed, for example.

[0052] The working head 13 is located at the end (end portion) of the second arm 12b on the second direction D2+ side. The working head 13 has: a spline nut 13a and a ball screw nut 13b, coaxially arranged on the third shaft A3; and a shaft 13c, which inserts the spline nut 13a and the ball screw nut 13b. The third shaft A3 is parallel to the first shaft A1 and the second shaft A2.

[0053] Shaft 13c is also referred to as a splined shaft or working shaft. Shaft 13c extends along the third axis A3. Shaft 13c is capable of rotating about the third axis A3 and moving up and down along the third axis A3. Specifically, shaft 13c rotates about the third axis A3 by rotating the spline nut 13a. In addition, shaft 13c moves up and down in the direction along the third axis A3 by rotating the ball screw nut 13b.

[0054] An end effector 13d is mounted on the lower end of the shaft 13c. The end effector 13d is removable from and detachable from the shaft 13c. While there is no particular limitation on the types of end effectors 13d, examples include hands, drills, and suction heads.

[0055] Spline nut 13a is disposed at the lower part of the second arm base 123. Ball screw nut 13b is located above spline nut 13a and is disposed from above the second arm base 123 throughout the interior of the second arm base 123. The positions of spline nut 13a and ball screw nut 13b are not limited as described above.

[0056] An upper stop 131 is provided at the upper end of the shaft 13c. When the shaft 13c is lowered, the upper stop 131 prevents the shaft 13c from disengaging from the second arm 12b downwards. Similarly, a lower stop 132 is provided at the lower part of the shaft 13c. When the shaft 13c is raised, the lower stop 132 prevents the shaft 13c from disengaging from the second arm 12b upwards.

[0057] A through hole is provided at the end of the second arm base 123, extending through the second arm base 123 along the third axis A3. Additionally, a through hole is provided at the end of the cover 124 on the second direction D2+ side, extending through the cover 124 along the third axis A3 in the thickness direction. The shaft member 13c is inserted through these through holes.

[0058] If the shaft 13c is lowered, its upper end and the upper stop 131 are housed within the cover 124. Furthermore, the descent range of the shaft 13c is limited by the robot 10's control program so that the shaft 13c does not descend further downwards, as in the state where the upper stop 131 is separated from the pulley 162b of the third drive unit 16 by a predetermined gap. Conversely, if the shaft 13c is raised, its upper end and the upper stop 131 are exposed to the outside of the cover 124. Furthermore, the rise range of the shaft 13c is limited by the robot 10's control program so that the shaft 13c does not rise further upwards, as in the state where... Figure 6 The lower stop 132 shown is positioned such that a predetermined gap is separated downwards from the spline nut 13a. Hereinafter, the distance the shaft 13c moves in the first direction D1 from its highest point to its lowest point will be referred to as the "maximum travel length S of the shaft 13c." That is, the maximum travel length S of the shaft 13c is equivalent to the difference in the Z-axis direction between the highest and lowest points of the shaft 13c. Since the upper end of the shaft 13c can be exposed to the outside of the cover 124, the maximum travel length S of the shaft 13c can be increased compared to the case where the cover 124 has a shape that always covers the upper end of the shaft 13c.

[0059] It should be noted that the state in which the shaft 13c is at its lowest point can also be the position where the upper stop 131 contacts the upper surface of the pulley 162b of the third drive unit 16. Conversely, the state in which the shaft 13c is at its highest point can also be the position where the lower stop 132 contacts the lower surface of the spline nut 13a. Furthermore, the user of the robot 10 can further limit the length by which the shaft 13c can be raised or lowered based on the position of the workpiece or other object positioned in the workspace, so that the shaft 13c can be raised or lowered with a length shorter than the maximum stroke length S that the shaft 13c can lift or lower. In this case, the maximum stroke length S that the shaft 13c can lift or lower also refers to the length that the shaft 13c could originally lift or lower before the user sets the limit.

[0060] Let H be the distance between the lower end of shaft 13c and support T1 in its most raised state. That is, H is the minimum distance between the lower end of shaft 13c and support T1. The units of S and H are the same. While not specifically limited, H and S preferably satisfy the relationship H ≤ 3S, more preferably H ≤ 2.7S, and even more preferably 1.4S ≤ H ≤ 2.5S. This makes it less likely for shaft 13c to interfere with workpieces, floors, or other objects located below it. In other words, the maximum stroke length S that shaft 13c can lift and lower can be fully and flexibly utilized. As a result, the types and range of operations that the robot 10 can perform can be expanded. Furthermore, the range of selectable end effectors 13d and workpieces mounted on shaft 13c can be expanded.

[0061] like Figure 1 As shown, the robot 10 also includes a first drive unit 14, a second drive unit 15, a third drive unit 16, and a fourth drive unit 17.

[0062] The first drive unit 14 rotates the first arm 12a relative to the base 11 about the first axis A1. The first drive unit 14 includes a first motor 141, a belt drive 142, and a reducer 200. The first motor 141 generates power to rotate the first arm 12a relative to the base 11. The belt drive 142 transmits the power from the first motor 141 to the reducer 200. The reducer 200 slows down the rotational speed from the first motor 141 transmitted from the belt drive 142 and transmits the power from the first motor 141 to the first arm 12a. Thus, in this specification, the phrase "slows down the rotational speed from the first motor 141 and transmits the power from the first motor 141 to the first arm 12a" allows for situations where other components such as the belt drive 142 are positioned between the first motor 141 and the reducer 200, and situations where other components such as the second support member 146 (described later) are positioned between the reducer 200 and the first arm 12a. The same applies to the second drive unit 15 (described later). It should be noted that the more detailed configuration of the first drive unit 14 will be described later.

[0063] The second drive unit 15 rotates the second arm 12b relative to the first arm 12a about a second axis A2. The second drive unit 15 includes a second motor 151, a belt drive 152, and a reducer 153. The second motor 151 generates power to rotate the second arm 12b relative to the first arm 12a. The belt drive 152 transmits the power of the second motor 151 to the reducer 153. The reducer 153 reduces the rotational speed of the second motor 151 transmitted from the belt drive 152 and transmits the power of the second motor 151 to the second arm 12b. Detailed configuration of the second drive unit 15 will be described later.

[0064] The third drive unit 16 causes the shaft 13c to move up and down along the third axis A3. The third drive unit 16 is housed in the housing 122b of the second arm 12b. The third drive unit 16 includes: a third motor 161 that generates power to move the shaft 13c up and down; and a transmission unit 162 that transmits the power of the third motor 161 to the shaft 13c.

[0065] The third motor 161 is mounted on the second arm base 123. The third motor 161 is located between the connecting part 122a and the shaft 13c. The output shaft of the third motor 161 protrudes downward from the motor housing of the third motor 161.

[0066] The transmission unit 162 is located on the second arm base 123. In this embodiment, the transmission unit 162 is constructed by a one-stage reduction belt drive. The transmission unit 162 has a pulley 162a, a pulley 162b, and an annular drive belt 162c. The pulley 162a is fixed to the output shaft of the third motor 161. The pulley 162b is coaxial with the shaft 13c, and the pulley 162b is fixed to the ball screw nut 13b. The annular drive belt 162c is wound around the pulleys 162a and 162b.

[0067] The fourth drive unit 17 rotates the shaft 13c about the third axis A3. The fourth drive unit 17 is housed within the housing 122b of the second arm 12b. The fourth drive unit 17 includes: a fourth motor 171 that generates power to rotate the shaft 13c; and a transmission unit 172 that decelerates the rotation from the fourth motor 171 and transmits the power from the fourth motor 171 to the shaft 13c.

[0068] A fourth motor 171 is mounted on the second arm base 123. The fourth motor 171 is located between the connecting portion 122a and the third motor 161. The output shaft of the fourth motor 171 protrudes downwards from the motor housing of the fourth motor 171. Alternatively, the third motor 161 and the fourth motor 171 can be arranged side-by-side on the third direction D3. Alternatively, the fourth motor 171 can be positioned between the third motor 161 and the shaft member 13c.

[0069] The transmission unit 172 is housed within the second arm base 123. In this embodiment, the transmission unit 172 is constructed using a two-stage reduction belt drive. The transmission unit 172 includes pulleys 172a and 172b, an annular drive belt 172c, a shaft member 172d, pulleys 172e and 172f, and an annular drive belt 172g. Pulley 172a is fixed to the output shaft of the fourth motor 171. Pulley 172b is located between pulley 172a and shaft member 13c. The annular drive belt 172c is wound around pulleys 172a and 172b. Pulley 172e is fixed coaxially with pulley 172b. Pulley 172f is coaxial with shaft member 13c and is fixed to spline nut 13a. The annular drive belt 172g is wound around pulleys 172e and 172f. The shaft component 172d is provided with pulleys 172b and 172e. The shaft component 172d is rotatably supported on the second arm base 123.

[0070] The number of deceleration stages in the transmission units 162 and 172 is not limited to the above. Furthermore, the transmission units 162 and 172 are not limited to belt drives, and may also be composed of gear devices such as planetary gear devices, wave gear devices, or devices that combine belt drives and gear devices.

[0071] The control device 30 is located on the outside of the robot 10. Alternatively, the control device 30 can be housed in the base 11. The control device 30 includes a storage unit, a control unit, and a communication unit. They are interconnected via a bus.

[0072] The storage unit consists of RAM (Random Access Memory) and ROM (Read Only Memory). It stores various programs and data, including control programs that control the robot 10's movements.

[0073] The control unit consists of at least one processor, such as a CPU (Central Processing Unit). The control unit reads and executes various programs stored in the storage unit.

[0074] The communication unit consists of various interfaces that enable communication with external devices such as the robot 10 and a teaching pendant (not shown). The communication unit transmits and receives information and signals between itself and these external devices. Communication can also be via networks such as a LAN (Local Area Network) or the Internet. Furthermore, the communication method can be wired or wireless.

[0075] Next, the connection structure between the base 11 and the first arm 12a will be described in detail.

[0076] like Figure 2 As shown, a first through hole 112h extending along the first axis A1 is provided in the base plate portion 112 of the base 11. Furthermore, a downwardly recessed portion 112d is provided on the upper surface of the base plate portion 112, around the outer periphery of the first through hole 112h. When viewed from above, the recess 112d is annular with the first axis A1 as its center.

[0077] The first motor 141 of the first drive unit 14 is disposed within the housing 11a. The first motor 141 is positioned at a point that is separated from the first axis A1 in a direction orthogonal to the first axis A1 (Y-axis direction + side) and separated upward from the bottom plate portion 112 of the housing 11a. With the output shaft of the first motor 141 protruding downward from the motor housing of the first motor 141, the motor housing of the first motor 141 is fixed to the housing 11a via a support member (not shown).

[0078] The belt drive device 142 of the first drive unit 14 is disposed within the housing 11a. The belt drive device 142 includes: a first pulley 142a connected to the output shaft of the first motor 141; a second pulley 142b rotating about the first shaft A1; and an annular drive belt 142c wound around the first pulley 142a and the second pulley 142b. The first pulley 142a and the second pulley 142b are located above the base plate 112. A radially extending threaded hole 142h is provided in the second pulley 142b. The threaded hole 142h connects the external and internal spaces of the second pulley 142b. In this embodiment, the outer diameter of the first pulley 142a and the outer diameter of the second pulley 142b are approximately equal. However, the outer diameter of the first pulley 142a may be larger or smaller than the outer diameter of the second pulley 142b.

[0079] In this embodiment, the reducer 200 of the first drive unit 14 is composed of a wave gear device. Compared with a winding transmission device, the wave gear device is more compact and has a larger reduction ratio. The reducer 200 has an input shaft 210 composed of a wave generator, an intermediate section 220 composed of a flexible wheel, an output shaft 230 composed of a rigid wheel, and a bearing 240. However, the reducer 200 can also be composed of other gear devices such as an eccentric oscillating gear device.

[0080] Although not specifically limited, in this embodiment, the reduction ratio of the reducer 200, i.e., the rotational speed of the input shaft 210 / the rotational speed of the output shaft 230, is preferably 10 or more and 200 or less, more preferably 50 or more and 150 or less.

[0081] The speed reducer 200 is housed within the housing 11a. In this specification, "speed reducer 200 is housed within the housing 11a" means that most of the speed reducer 200 is disposed within the housing 11a, while a portion of the speed reducer 200 is allowed to protrude beyond the housing 11a. By housing the speed reducer 200 within the housing 11a, compared to the case where the entire speed reducer 200 is located outside the base 11, the separation distance G1 between the base 11 and the first arm 12a in the direction parallel to the first shaft A1 can be shortened. Therefore, the lower end of the shaft 13c disposed on the second arm 12b is less likely to interfere with workpieces, floors, or other objects disposed below the shaft 13c. Thus, the maximum stroke length S that the shaft 13c can lift can be fully and flexibly utilized.

[0082] Although not specifically limited, the separation distance G1 between the base 11 and the first arm 12a, i.e., the separation distance G1 between the base plate portion 112 and the first arm base 121a, is preferably 2.0 mm or more and 4.0 mm or less, more preferably 2.5 mm or more and 3.5 mm or less. This allows the first arm 12a to rotate flexibly relative to the base 11 and prevents the base 11 and the first arm 12a from being too far apart.

[0083] Furthermore, a portion of the reducer 200 is disposed within the first through hole 112h. This allows the reducer 200 to be housed within the housing 11a of the base 11, preventing excessive separation between the reducer 200 and the first arm 12a. Consequently, the bending moment applied to the reducer 200 due to rotation of the first arm 12a is reduced, and shaft wobble of the reducer 200's input shaft 210, output shaft 230, and other components is less likely to occur. As a result, wear on various parts of the reducer 200 is suppressed, and the lifespan of the reducer 200 is extended. Additionally, this reduces power transmission losses from the reducer 200 to the first arm 12a.

[0084] It should be noted that the higher the reducer 200 is positioned, the more necessary it is to place the first motor 141 and belt drive 142 above it. Consequently, the length of the housing 11a increases in the direction parallel to the first axis A1. The base 11 of the ceiling-mounted robot 10 is often located inside a ceiling where space is limited. Therefore, as in this embodiment, by placing the reducer 200 at the lower part of the housing 11a, the increase in the length of the housing 11a in the direction parallel to the first axis A1 can be suppressed. Thus, the base 11 of the ceiling-mounted robot 10 can be easily placed inside a ceiling where space is limited.

[0085] The total length of the reducer 200 in the Z-axis direction is defined as L0, and the length of the portion of the reducer 200 located below the lower surface of the base plate 112 in the Z-axis direction is defined as L1. The units of L0 and L1 are set to be the same. At this time, although there is no particular limitation, L1 / L0×100 [%] is preferably 0% or more and 10% or less, more preferably 5% or more and 10% or less.

[0086] The input shaft 210 is configured along the first shaft A1 and rotates around the first shaft A1 by power transmitted from the first motor 141 via the second pulley 142b. The input shaft 210 has a cylindrical main body 211 and a bearing 212 disposed inside the main body 211.

[0087] The main body 211 is constructed of a rigid body. The upper end of the main body 211 is located above the base plate 112, and the main body 211 passes through the first through hole 112h. Therefore, the reducer 200 can be housed within the housing 11a, and the excessive separation between the reducer 200 and the first arm 12a can be prevented. The lower end of the main body 211 is located below the base plate 112 and protrudes further downward than the output shaft 230. Figure 3 As shown, the outer peripheral surface of the portion of the main body 211 in which the bearing 212 is mounted is elliptical when viewed from above. Thus, because the outer peripheral surface of the main body 211 has an elliptical shape, it is also called an elliptical cam.

[0088] like Figure 2 As shown, the upper end of the main body 211 is disposed inside the second pulley 142b. Furthermore, the set screw 142s is threaded into the threaded hole 142h of the second pulley 142b and is pressed against the outer peripheral surface (side surface) of the main body 211. Assuming that the second pulley 142b is fixed to the main body 211 by a screw whose threaded shaft extends in a direction parallel to the first axis A1, it would be necessary to provide a threaded hole extending in a direction parallel to the first axis A1 in the main body 211, and correspondingly, the radial wall thickness of the main body 211 would need to be increased. In contrast, in this embodiment, since it is not necessary to provide a threaded hole in the input shaft 210, the radial wall thickness of the input shaft 210 can be reduced. Therefore, although details will be described later, the inner diameter of the sleeve 147 disposed inside the main body 211 can be increased. As a result, the number of linear members passing through the inner side of the sleeve 147 can be increased. The method of fixing the second pulley 142b and the input shaft 210 is not limited to the method of using the set screw 142s described above. For example, the second pulley 142b can also be fixed to the input shaft 210 by a screw with a threaded shaft extending in a direction parallel to the first shaft A1.

[0089] The bearing 212 of the input shaft 210 is a deep groove ball bearing, having an inner ring 213, an outer ring 214, rolling elements 215, and a retainer 216. Alternatively, the bearing 212 can be constructed from other ball bearings such as angular contact ball bearings, or other rolling bearings such as roller bearings. The bearing 212 is located slightly above the lower end of the main body 211. The bearing 212 is disposed within the first through hole 112h.

[0090] The inner ring 213 and the outer ring 214 are elastic. The inner ring 213 is fixed to the outer peripheral surface of the main body 211 and rotates together with the main body 211 around the first axis A1. Figure 3 As shown, the inner ring 213 and the outer ring 214 are elliptical in shape, mimicking the elliptical shape of the main body 211.

[0091] like Figure 2 As shown, the intermediate portion 220 is composed of a so-called top hat-shaped flexible wheel. An input shaft 210 is disposed inside the intermediate portion 220. The intermediate portion 220 has: a cylindrical portion 221, which is flexible and extends along the first axis A1; and an annular outer peripheral portion 222, which is connected to the upper end of the cylindrical portion 221 and extends radially outward from the cylindrical portion 221.

[0092] The upper end of the cylindrical portion 221 is located above the base plate portion 112. An external gear 221a is provided at the lower end of the cylindrical portion 221. The external gear 221a is disposed within the first through hole 112h. The lower end of the external gear 221a is approximately flush with the lower surface of the base plate portion 112. Figure 3 As shown, a bearing 212 for the input shaft 210 is disposed inside the external gear 221a, and the inner side of the external gear 221a is in contact with the outer ring 214 of the bearing 212. That is, the external gear 221a and the outer ring 214 correspond to the "contact portion 210A" between the input shaft 210 and the intermediate portion 220. Furthermore, the contact portion 210A is located within the first through hole 112h.

[0093] The external gear 221a is shaped to mimic the shape of the outer ring 214 of the input shaft 210. Therefore, the virtual curve C1 connecting the multiple tooth tips of the external gear 221a is elliptical, mimicking the shape of the outer ring 214 of the input shaft 210. Thus, if the main body 211 rotates, the positions of the major and minor axes of the outer circumferential surface of the main body 211 change around the first axis A1 when viewed from above. Correspondingly, the positions of the major and minor axes of the curve C1 also change around the first axis A1.

[0094] like Figure 2 As shown, the bearing 240 fixes the intermediate portion 220 to the housing 11a and supports the output shaft 230 so that it can rotate. In this embodiment, the bearing 240 is constructed by a crossed roller bearing and has an inner ring 241, an outer ring 242, and rolling elements 243. The cylindrical portion 221 of the intermediate portion 220 is disposed inside the bearing 240. The upper end of the inner ring 241, the upper end of the outer ring 242, and the rolling elements 243 of the bearing 240 are located above the base plate portion 112.

[0095] The inner ring 241 is separated from the middle part 220. The lower end of the inner ring 241 is located in the first through hole 112h and is fixed to the output shaft 230.

[0096] The outer ring 242 is equivalent to a "fixed part" fixed to the housing 11a in the reducer 200. The outer peripheral portion 222 of the intermediate portion 220 is fixed to the upper surface of the outer ring 242. The lower end of the outer ring 242 is disposed in the recess 112d of the base plate portion 112 and is fixed to the base plate portion 112 by screws or the like. Therefore, the reducer 200 can be placed in the housing 11a of the base 11, and the situation where the reducer 200 and the first arm 12a are too separated can be suppressed. In addition, the situation where the rolling element 243 and the first arm 12a are too separated can be suppressed. As a result, the bending moment applied due to the rotation of the first arm 12a in the bearing 240 near the rolling element 243 can be reduced. As a result, the wear of the bearing 240 can be suppressed. As a result, the service life of the reducer 200 can be increased. It is also possible to form a structure in which the recess 112d is not provided in the base plate portion 112.

[0097] The output shaft 230 outputs a reduced rotational speed. That is, the output shaft 230 rotates at a reduced rotational speed relative to the input shaft 210. The entire output shaft 230 is disposed within the first through-hole 112h. Therefore, the reducer 200 can be housed within the housing 11a of the base 11, and the excessive separation between the reducer 200 and the first arm 12a is prevented. In this embodiment, the lower end of the output shaft 230 is flush with the lower surface of the base plate 112. Alternatively, the lower end of the output shaft 230 may be located above the lower surface of the base plate 112. Furthermore, a portion of the output shaft 230 may protrude upwards or downwards from the first through-hole 112h.

[0098] The output shaft 230 is constructed of a rigid body. For example... Figure 3 As shown, the output shaft 230 is composed of an internal gear. The number of teeth on the output shaft 230 is greater than the number of teeth on the external gear 221a located in the intermediate section 220. Furthermore, the curve connecting the multiple tooth tips on the output shaft 230 is circular.

[0099] Therefore, a portion of the teeth of the external gear 221a located in the intermediate portion 220 meshes with a portion of the teeth of the output shaft 230. More specifically, the teeth of all the teeth of the external gear 221a located near the long axis of the outer peripheral surface of the main body 211, and the teeth of all the teeth of the output shaft 230 located near the long axis of the outer peripheral surface of the main body 211, mesh. Furthermore, the teeth of all the teeth of the external gear 221a located near the short axis of the outer peripheral surface of the main body 211, and the teeth of all the teeth of the output shaft 230 located near the short axis of the outer peripheral surface of the main body 211, do not mesh and are separated from each other.

[0100] As mentioned earlier, if the main body 211 and the inner ring 213 of the bearing 212 rotate around the first axis A1, then, in a top view, the positions of the major and minor axes of the curve C1 of the multiple tooth tips of the external gear 221a connecting the intermediate part 220 also change around the first axis A1. Therefore, the meshing position of the external gear 221a and the output shaft 230 changes around the first axis A1 according to the position of the major axis of the outer circumferential surface of the main body 211. As mentioned earlier, the number of teeth on the output shaft 230 is greater than the number of teeth on the intermediate part 220. Even if the input shaft 210 rotates one revolution, the output shaft 230 only rotates by a rotation angle equivalent to the difference in the number of teeth between the intermediate part 220 and the output shaft 230. Therefore, the rotational speed of the output shaft 230 is slower than the rotational speed of the input shaft 210. That is, the output shaft 230 can output a decelerated rotation.

[0101] The contact portion 230A between the external gear 221a of the intermediate portion 220 and the output shaft 230 is located within the first through hole 112h. Furthermore, as mentioned earlier, the contact portion 210A between the input shaft 210 and the intermediate portion 220 is also located within the first through hole 112h. Therefore, the reducer 200 can be housed within the housing 11a of the base 11, and the excessive separation between the power transmission portion of the reducer 200 and the first arm 12a can be prevented. This reduces power transmission loss from the reducer 200 to the first arm 12a. Additionally, since the contact portions 210A and 230A are at the same position (height) in the Z-axis direction, the length (height) of the reducer 200 in the Z-axis direction can be relatively reduced.

[0102] like Figure 2 As shown, the first drive unit 14 also includes a first bearing 144a, a second bearing 144b, a first support member 145, and a second support member 146.

[0103] The first bearing 144a supports the input shaft 210 so that it can rotate and is located above the base plate portion 112. The inner ring of the first bearing 144a is fixed in the main body portion 211 of the input shaft 210 in a position above the bearing 240 and below the second pulley 142b.

[0104] The first support member 145 is annular with the first shaft A1 as its center, and a first bearing 144a is disposed on the inner side of the first support member 145. The outer ring of the first bearing 144a is fixed to the first support member 145. That is, the first support member 145 supports the first bearing 144a. The first support member 145 is fixed to the outer periphery 222 of the intermediate portion 220. That is, the first support member 145 is fixed to the housing 11a via the intermediate portion 220 and the outer ring 242 of the bearing 240.

[0105] The second bearing 144b supports the input shaft 210 so that it can rotate and is located below the base plate portion 112. The inner ring of the second bearing 144b is fixed in the main body portion 211 of the input shaft 210 at a position below the base plate portion 112. Through the first bearing 144a and the second bearing 144b, both the portion of the input shaft 210 located above the base plate portion 112 and the portion located below the base plate portion 112 can be supported. Therefore, shaft runout of the input shaft 210 can be further suppressed. Consequently, wear on the reducer 200 can be further suppressed, and the lifespan of the reducer 200 can be further extended.

[0106] The second support member 146 supports the second bearing 144b and connects the output shaft 230 and the first arm 12a. The second support member 146 is annular with the first shaft A1 as its center, and the second bearing 144b is disposed on the inner side of the second support member 146. The outer ring of the second bearing 144b is fixed to the second support member 146. In this way, since the support of the second bearing 144b and the connection between the output shaft 230 and the first arm 12a can be achieved by a single component, the base 11 and the first arm 12a can be brought closer together. In addition, compared with the case where the support of the second bearing 144b and the connection between the output shaft 230 and the first arm 12a are achieved by different components, the number of components can be reduced. Alternatively, the support of the second bearing 144b and the connection between the output shaft 230 and the first arm 12a can be achieved by different components.

[0107] A second through hole 121h is provided on the upper wall of the first arm base 121a, opposite to the reducer 200. Furthermore, a downwardly recessed portion 121d is provided on the outer periphery of the second through hole 121h in the upper wall of the first arm base 121a. When viewed from above, the recess 121d is annular with the first shaft A1 as its center.

[0108] The second support member 146 has: a first portion 146a that contacts the upper surface of the first arm base 121a; and a second portion 146b that protrudes downward from the inner periphery of the first portion 146a and is disposed within the second through hole 121h. The lower end of the output shaft 230 is fixed to the upper end of the first portion 146a. The lower end of the first portion 146a is disposed within the recess 121d and fixed to the first arm base 121a by screws or the like. In this way, by having the first portion 146a of the second support member 146 contact the upper surface of the first arm base 121a and the second portion 146b embedded in the second through hole 121h, misalignment of the second support member 146 relative to the first arm 12a can be suppressed during rotation of the first arm 12a. Alternatively, the recess 121d may not be provided in the first arm base 121a.

[0109] A sleeve 147 is disposed inside the second pulley 142b, the input shaft 210, and the second portion 146b of the second support member 146. The sleeve 147 forms a channel for the linear component to pass through. The sleeve 147 is cylindrical and extends along the first shaft A1. The sleeve 147 is separated from the second pulley 142b and the input shaft 210, and is fixed to the second portion 146b of the second support member 146. That is, the sleeve 147 rotates integrally with the output shaft 230, the second support member 146, and the first arm 12a.

[0110] While not specifically limited, the portion of the second support member 146 located above the upper end of the first arm base 121a has a length in the Z-axis direction that is preferably 2 mm or more and 8 mm or less, more preferably 2.5 mm or more and 7.5 mm or less. By ensuring that the length of the portion of the second support member 146 located above the upper end of the first arm base 121a in the Z-axis direction is at least the aforementioned lower limit, the second bearing 144b can be disposed inside the second support member 146. Furthermore, by ensuring that the length of the portion of the second support member 146 located above the upper end of the first arm base 121a in the Z-axis direction is at least the aforementioned upper limit, the possibility of the overall length of the second support member 146 in the Z-axis direction increasing can be prevented.

[0111] In this embodiment, although the lower end of the output shaft 230 is flush with the lower surface of the base plate portion 112, the lower end of the output shaft 230 may also be located above the lower surface of the base plate portion 112. In this case, the distance between the lower end of the output shaft 230 and the lower surface of the base plate portion 112 in the Z-axis direction is preferably the length of the portion of the second support member 146 located above the upper end of the first arm base 121a in the Z-axis direction, minus the preferred separation distance G1 between the base plate portion 112 and the first arm base 121a. Although not particularly limited, the distance between the lower end of the output shaft 230 and the lower surface of the base plate portion 112 in the Z-axis direction is preferably 0 mm or more and 6 mm or less, more preferably 0 mm or more and 5 mm or less.

[0112] The positions and shapes of the input shaft 210, intermediate section 220, output shaft 230, and bearing 240 of the reducer 200 are not limited to those described and illustrated above. For example, the cylindrical portion 221 of the intermediate section 220 and the lower end of the output shaft 230 may protrude further downward than the base plate 112. Alternatively, the lower end of the input shaft 210 may be located above the lower surface of the base plate 112. In this case, the lower end of the input shaft 210 may not be supported by the second bearing 144b.

[0113] Next, the second drive unit 15 will be described in detail.

[0114] like Figure 1 As shown, the belt drive device 152 of the second drive unit 15 includes: a third pulley 152a connected to the output shaft of the second motor 151; a fourth pulley 152b with the second shaft A2 as the central axis; and an annular drive belt 152c wound around the third pulley 152a and the fourth pulley 152b.

[0115] The reducer 153 of the second drive unit 15 is constructed using a wave gear assembly. Furthermore, although not shown in the figure, the input shaft of the reducer 153, like the input shaft 210 of the reducer 200 of the first drive unit 14, is fixed to the fourth pulley 152b using set screws. Therefore, compared to the case where the fourth pulley 152b is fixed to the input shaft of the reducer 153 using screws with threaded shafts extending in a direction parallel to the second shaft A2, the radial wall thickness of the input shaft of the reducer 153 can be reduced. Thus, for the reducer 153 of the second drive unit 15, sufficient space can be ensured inside the input shaft for the insertion of the linear component.

[0116] The reducer 153 can be composed of other gear devices such as an eccentric oscillating gear device, or a winding transmission device such as a belt drive device. Furthermore, the method of fixing the fourth pulley 152b and the input shaft of the reducer 153 is not limited to using the aforementioned set screw method. For example, the fourth pulley 152b can also be fixed to the input shaft of the reducer 153 using a screw with a threaded shaft extending in a direction parallel to the second shaft A2.

[0117] As described above, the robot 10 according to this embodiment includes a base 11, a first arm 12a, a second arm 12b, a shaft 13c, a first motor 141, a reducer 200, a second motor 151, and a third motor 161. The base 11 has a housing 11a. The first arm 12a is disposed below the base 11 and is rotatable relative to the base 11 about a first axis A1. The second arm 12b is disposed below the first arm 12a and is rotatable relative to the first arm 12a about a second axis A2 parallel to the first axis A1. The shaft 13c is disposed at the end of the second arm 12b and is movable along a third axis A3 parallel to the second axis A2. The first motor 141 is disposed within the housing 11a and generates power to rotate the first arm 12a relative to the base 11. The reducer 200 is disposed within the housing 11a to reduce the rotation of the first motor 141 and transmit power to the first arm 12a. The second motor 151 generates power to rotate the second arm 12b relative to the first arm 12a. The third motor 161 generates power to raise and lower the shaft 13c.

[0118] The housing 11a has a base plate 112, which has a first through hole 112h extending along the first axis A1. A portion of the reducer 200 is disposed within the first through hole 112h. The first arm 12a has: a first arm base 121a extending in a direction orthogonal to the first axis A1; and a receiving portion 121b protruding downward from the first arm base 121a to receive the second motor 151 and being separated from the second arm 12b.

[0119] By placing the reducer 200 inside the housing 11a of the base 11, compared to the case where the reducer 200 is entirely located outside the base 11, the first arm 12a can be brought closer to the base 11. Furthermore, since the housing 121b housing the second motor 151 protrudes downwards from the first arm base 121a, the housing 121b and the base 11 do not interfere with each other during the rotation of the first arm 12a. Therefore, compared to the case where the housing 121b protrudes upwards from the first arm base 121a, the first arm 12a can be brought closer to the base 11. Consequently, the lower end of the shaft 13c provided on the second arm 12b is less likely to interfere with objects such as workpieces or floors located below the shaft 13c. Therefore, the maximum stroke length S that the shaft 13c can lift can be fully and flexibly utilized. As a result, the types and range of operations that the robot 10 can perform can be expanded. In addition, the range of choices for the end effector 13d mounted on the shaft 13c and the workpiece can be expanded.

[0120] Furthermore, a portion of the reducer 200 is disposed within the first through hole 112h of the base plate portion 112. This allows the reducer 200 to be disposed within the housing 11a of the base 11, preventing excessive separation between the reducer 200 and the first arm 12a. Consequently, the bending moment applied to the reducer 200 from the first arm 12a when the first arm 12a rotates is reduced, making it difficult for the input shaft 210, output shaft 230, and other parts of the reducer 200 to experience shaft wobble. As a result, wear on various parts of the reducer 200 can be suppressed, extending the lifespan of the reducer 200. Additionally, this reduces power transmission losses from the reducer 200 to the first arm 12a. Furthermore, this allows the reducer 200 to be housed within the housing 11a, preventing an increase in the length of the housing 11a in the direction parallel to the first shaft A1.

[0121] Additionally, the reducer 200 includes: an input shaft 210, configured along a first shaft A1 and rotating about the first shaft A1 by power from a first motor 141; and an output shaft 230, configured coaxial with the input shaft 210, outputting the reduced rotation. The output shaft 230 is disposed within a first through hole 112h.

[0122] Therefore, the reducer 200 can be housed within the housing 11a of the base 11, preventing the reducer 200 from being excessively separated from the first arm 12a. This allows for full and flexible utilization of the maximum stroke length S that the shaft 13c can lift, and extends the lifespan of the reducer 200.

[0123] In addition, the upper end of the input shaft 210 is located above the bottom plate portion 112, and the input shaft 210 passes through the first through hole 112h.

[0124] Therefore, the reducer 200 can be housed within the housing 11a of the base 11, and the situation where the reducer 200 and the first arm 12a are too separated can be prevented.

[0125] Additionally, the lower end of the input shaft 210 is located below the base plate 112. The robot 10 also includes: a first bearing 144a, which supports the input shaft 210 so that it can rotate and is located above the base plate 112; and a second bearing 144b, which supports the input shaft 210 so that it can rotate and is located below the base plate 112.

[0126] Therefore, the shaft runout of the input shaft 210 can be further suppressed. As a result, the wear of various parts of the reducer 200 can be further suppressed, and the service life of the reducer 200 can be further extended.

[0127] Additionally, the reducer 200 also has an intermediate portion 220 located between the input shaft 210 and the output shaft 230, which transmits the rotation of the input shaft 210 to the output shaft 230. The upper end of the intermediate portion 220 is located above the base plate portion 112. The contact portion 230A between the intermediate portion 220 and the output shaft 230 is located within the first through hole 112h.

[0128] Therefore, the reducer 200 can be housed within the housing 11a of the base 11, and the excessive separation between the power transmission portion of the reducer 200 and the first arm 12a can be prevented. This reduces power transmission loss from the reducer 200 to the first arm 12a.

[0129] In addition, the contact portion 210A between the input shaft 210 and the intermediate portion 220 is located within the first through hole 112h.

[0130] Therefore, the reducer 200 can be housed within the housing 11a of the base 11, preventing excessive separation between the power transmission portion of the reducer 200 and the first arm 12a. This reduces power transmission loss from the reducer 200 to the first arm 12a. Furthermore, since the contact portions 210A and 230A are at the same height, the overall height of the reducer 200 can be relatively reduced.

[0131] In addition, the robot 10 also has a second support member 146, which supports the second bearing 144b and connects the output shaft 230 and the first arm 12a.

[0132] In this way, since the second bearing 144b can be supported and the output shaft 230 and the first arm 12a can be connected by a single component, the first arm 12a can be brought closer to the base 11. In addition, compared with the case where the second bearing 144b is supported and the output shaft 230 and the first arm 12a are connected by different components, the number of components can be reduced.

[0133] Additionally, a second through hole 121h is provided in the first arm base 121a at a position opposite to the reducer 200. The second support member 146 has: a first portion 146a that contacts the upper surface of the first arm base 121a; and a second portion 146b that protrudes downward from the first portion 146a and is disposed within the second through hole 121h.

[0134] In this way, by making the first part 146a of the support member contact the upper surface of the first arm base 121a and embedding the second part 146b into the second through hole 121h, the misalignment of the second support member 146 relative to the first arm 12a can be suppressed when the first arm 12a rotates.

[0135] In addition, the reducer 200 has a fixing part (outer ring 242 of bearing 240) fixed to the housing 11a. A recess 112d is provided on the outer periphery of the first through hole 112h in the upper surface of the base plate 112, and the fixing part is disposed in the recess 112d.

[0136] Therefore, the reducer 200 can be housed within the housing 11a of the base 11, and the situation where the reducer 200 and the first arm 12a are too separated can be prevented.

[0137] Additionally, the second arm 12b includes: a second arm base 123 extending in a direction orthogonal to the second axis A2, and equipped with a third motor 161; and a cover 124 detachably mounted to the second arm base 123. The maximum length H1 of the cover 124 in the first direction D1, for example along the second axis A2, is greater than the maximum length H2 of the receiving portion 121b in the first direction D1, for example along the second axis A2.

[0138] Therefore, the receiving portion 121b can be positioned below the first arm base 121a, and the maximum length of the internal space of the cover 124 along the second axis A2 can be sufficiently ensured.

[0139] Additionally, a connector 124i is provided on the upper surface of the cover 124. When viewed from a direction parallel to the second axis A2, the receiving portion 121b is located inside the rotation track of the connector 124i when the second arm 12b is rotated.

[0140] Therefore, it is possible to prevent the connector 124i, which is provided on the upper surface of the cover 124, and the linear component connected to the connector 124i from contacting the receiving portion 121b. As a result, the second arm 12b can rotate flexibly relative to the first arm 12a.

[0141] In addition, the cross-sectional shape of the first arm base 121a orthogonal to the long side direction and the cross-sectional shape of the second arm base 123 orthogonal to the long side direction are the same.

[0142] In this way, by using components with the same cross-sectional shape as the components of the first arm base 121a and the second arm base 123, the robot 10 can be manufactured easily and efficiently. In particular, such components with the same cross-sectional shape can be manufactured by extrusion molding using the same molding die. Therefore, when using extrusion molding to manufacture such first arm base 121a and second arm base 123, the molding die can be standardized.

[0143] Additionally, the input shaft 210 is cylindrical. The robot 10 also includes a first pulley 142a, a second pulley 142b, an annular drive belt 142c, and set screws 142s. The first pulley 142a is connected to the output shaft of the first motor 141. The second pulley 142b has the input shaft 210 of the reducer 200 disposed inside it and has a radially extending threaded hole 142h. The annular drive belt 142c is wound around the first pulley 142a and the second pulley 142b. The set screws 142s are disposed within the threaded hole 142h and are pressed against the input shaft 210 of the reducer 200.

[0144] Therefore, compared to the case where the second pulley 142b is fixed to the input shaft 210 of the reducer 200 by a screw extending along the first shaft A1 via a threaded shaft, the radial wall thickness of the input shaft 210 can be reduced. This ensures sufficient space for the insertion of the linear component within the input shaft 210.

[0145] Additionally, the base 11 is fixed to the support body T1, which is located above the first arm 12a. Let S be the maximum stroke length that the shaft 13c can lift, and let H be the distance between the lower end of the shaft 13c in its most raised state and the support body T1. At this point, the following relationship is satisfied: H ≤ 3S.

[0146] Therefore, the shaft 13c is unlikely to interfere with objects such as workpieces located below it. That is, the shaft 13c can make full use of its maximum lifting stroke length S.

[0147] The robot according to the present invention has been described above with reference to the illustrated embodiments, but the present invention is not limited thereto. Furthermore, the various parts of the robot can be replaced with any structure capable of performing the same function. Additionally, any structure may be added to the robot.

Claims

1. A robot, characterized in that, have: The base has a shell; The first arm is located below the base and is capable of rotating about a first axis relative to the base; The second arm is located below the first arm and is capable of rotating about a second axis relative to the first arm, the second axis being parallel to the first axis; A shaft is provided at the end of the second arm and is capable of moving up and down along a third axis, which is parallel to the second axis; A first motor, disposed within the housing, generates power to rotate the first arm relative to the base; A speed reducer is installed inside the housing to reduce the rotation speed of the first motor and transmit the power to the first arm; The second motor generates the power to rotate the second arm relative to the first arm; as well as The third motor generates the power to raise and lower the shaft. The housing has a bottom plate portion, and the bottom plate portion is provided with a first through hole extending along the first axis. A portion of the speed reducer is disposed within the first through hole. The first arm has: a first arm base extending in a direction orthogonal to the first axis; and a receiving portion protruding downward from the first arm base to receive the second motor and being separated from the second arm.

2. The robot according to claim 1, characterized in that, The speed reducer includes: an input shaft, configured along the first shaft and rotating about the first shaft by the power of the first motor; and an output shaft, configured coaxial with the input shaft, outputting the reduced rotation. The output shaft is disposed within the first through hole.

3. The robot according to claim 2, characterized in that, The upper end of the input shaft is located above the base plate. The input shaft passes through the first through hole.

4. The robot according to claim 3, characterized in that, The lower end of the input shaft is located below the base plate. The robot also has the following features: A first bearing supports the input shaft so that it is rotatable and is located above the base plate; and The second bearing supports the input shaft so that it can rotate and is located below the base plate.

5. The robot according to claim 4, characterized in that, The reducer also has an intermediate section located between the input shaft and the output shaft, which transmits the rotation of the input shaft to the output shaft. The upper end of the middle part is located above the bottom plate part. The contact portion between the middle section and the output shaft is located within the first through hole.

6. The robot according to claim 5, characterized in that, The contact portion between the input shaft and the intermediate portion is located within the first through hole.

7. The robot according to any one of claims 4 to 6, characterized in that, The robot also has a support component that supports the second bearing and connects the output shaft and the first arm.

8. The robot according to claim 7, characterized in that, A second through hole is provided in the first arm base at a position opposite to the reducer. The support component has: a first portion that contacts the upper surface of the first arm base; And a second portion, which protrudes downward from the first portion and is disposed within the second through hole.

9. The robot according to any one of claims 1 to 6, characterized in that, The speed reducer has a fixing part that is fixed to the housing. A recess is provided on the outer periphery of the first through hole in the upper surface of the base plate, and the fixing part is disposed in the recess.

10. The robot according to any one of claims 1 to 6, characterized in that, The second arm includes: a second arm base extending in a direction orthogonal to the second axis and provided with the third motor; and a cover detachably mounted to the second arm base. The maximum length of the cover along the second axis is greater than the maximum length of the receiving portion along the second axis.

11. The robot according to claim 10, characterized in that, A connector is provided on the upper surface of the cover. When viewed from a direction parallel to the second axis, the receiving portion is located inside the rotation track of the connector when the second arm is rotated.

12. The robot according to claim 10, characterized in that, The cross-sectional shape of the first arm base orthogonal to the long side direction and the cross-sectional shape of the second arm base orthogonal to the long side direction are the same.

13. The robot according to any one of claims 2 to 6, characterized in that, The input shaft is cylindrical. The robot also has the following features: The first pulley is connected to the output shaft of the first motor; The second pulley has the input shaft of the reducer disposed on its inner side and is provided with a threaded hole extending radially. An annular drive belt is wound around the first pulley and the second pulley; as well as A set screw is disposed in the threaded hole and pressed against the input shaft of the reducer.

14. The robot according to any one of claims 1 to 6, characterized in that, The base is fixed to the support body, which is located above the first arm. When the maximum travel length of the shaft that can be raised and lowered is set as S, and the distance between the lower end of the shaft and the support body in the most raised state is set as H, the following relationship is satisfied: H≤3S.

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