Horizontal articulated robot

Abstract

Provided is a horizontal multi-joint robot that can increase the lifting amount of an arm without changing the height of the horizontal multi-joint robot when the arm is lowered to a lower limit position, and that can be downsized in the horizontal direction. In a horizontal multi-joint robot (1), a first distance in the horizontal direction between a first rotation center that is the rotation center of a first arm section (15) with respect to a main body section (13) and a second rotation center that is the rotation center of a second arm section (16) with respect to the first arm section (15) is shorter than a second distance in the horizontal direction between the second rotation center and a third rotation center that is the rotation center of a third arm section (17) with respect to the second arm section (16). In the horizontal multi-joint robot (1), an upper end portion of an arm lifting mechanism (20) is disposed to the side of the base end portion of the first arm section (15) when the arm (12) is lowered to the lower limit position.

Description

Technical Field

[0001] This invention relates to a horizontal multi-joint robot in which the arm moves in the horizontal direction. Background Technology

[0002] Previously, horizontal articulated robots for transporting semiconductor wafers were known (for example, see Patent Document 1). The horizontal articulated robot described in Patent Document 1 was assembled into a semiconductor manufacturing system for use. The semiconductor manufacturing system has an EFEM (Equipment Front End Module), and the horizontal articulated robot is part of the EFEM. The EFEM has a housing for housing the horizontal articulated robot.

[0003] Patent Document 1 describes a horizontal multi-joint robot comprising: a hand carrying a semiconductor chip; an arm rotatably connected to the hand at its front end; and a main body rotatably connected to the base end of the arm. The arm has a first arm rotatably connected to the main body at its base end, a second arm rotatably connected to the front end of the first arm at its base end, and a third arm rotatably connected to the front end of the second arm at its base end. The hand is rotatably connected to the front end of the third arm. The first arm is positioned above the main body, the second arm is positioned above the first arm, the third arm is positioned above the second arm, and the hand is positioned above the third arm.

[0004] Furthermore, the horizontal articulated robot described in Patent Document 1 possesses an arm lifting mechanism for raising and lowering the arm. The arm lifting mechanism includes: a drive mechanism comprising a ball screw and a motor for rotating the ball screw shaft; and a guide mechanism comprising a guide rail and a guide block engaging with the guide rail. The arm lifting mechanism is housed inside the main body and positioned below the first arm. That is, the ball screw and guide rail, which constitute part of the arm lifting mechanism, are positioned below the first arm. [Existing Technical Documents] [Patent Literature]

[0005] Patent Document 1: Japanese Patent Application Publication No. 2015-36186 Summary of the Invention

[0006] In the horizontal articulated robot described in Patent Document 1, if the lifting range of the arm can be increased without changing the height of the horizontal articulated robot when the arm descends to the lower limit position, then the horizontal articulated robot can be used in various semiconductor manufacturing systems, thus improving its versatility. Therefore, the horizontal articulated robot described in Patent Document 1 is preferably configured in this way. Furthermore, in semiconductor manufacturing systems, it is preferable that the horizontal articulated robot housed in the housing is small in the horizontal direction.

[0007] Therefore, the objective of this invention is to provide a horizontal multi-joint robot that, in a horizontal multi-joint robot whose arm moves in the horizontal direction, can increase the lifting range of the arm without changing the height of the horizontal multi-joint robot when the arm descends to the lower limit position, and can also be miniaturized in the horizontal direction.

[0008] To address the aforementioned issues, the present invention provides a horizontal multi-joint robot whose arm moves in a horizontal direction. It is characterized by comprising: a hand that carries and transports an object; an arm rotatably connected to the hand at its front end; a main body rotatably connected to the base end of the arm; and an arm lifting mechanism for raising and lowering the arm. The arm includes: a first arm rotatably connected to the main body at its base end; and a second arm rotatably connected to the front end of the first arm at its base end. The lower surface of the first arm is connected to the upper surface of the main body, and the lower surface of the second arm is connected to the upper surface of the first arm. A lifting mechanism is provided at the front end of the second arm. The arm lifting mechanism is rotatably connected to the base end of a third arm or the base end of a hand that forms part of the arm. The first distance is shorter than the second distance. The first distance is the horizontal distance between a first rotation center, which is the rotation center of the first arm relative to the main body, and a second rotation center, which is the rotation center of the second arm relative to the first arm. The second distance is the horizontal distance between the third rotation center of the third arm or the hand connected to the second arm and the second rotation center. When the arm is lowered to the lower limit position, the upper end of the arm lifting mechanism is positioned to the side of the base end of the first arm.

[0009] In the horizontal articulated robot of the present invention, when the arm descends to the lower limit position, the upper end of the arm lifting mechanism is positioned to the side of the base end of the first arm. Therefore, in the present invention, compared to the case where the entire arm lifting mechanism is positioned below the first arm, the height of the arm lifting mechanism can be increased without changing the height of the horizontal articulated robot when the arm descends to the lower limit position. Therefore, in the present invention, the lifting range of the arm can be increased without changing the height of the horizontal articulated robot when the arm descends to the lower limit position.

[0010] Furthermore, in this invention, the horizontal distance between the first rotation center of the first arm relative to the main body and the second rotation center of the second arm relative to the first arm, i.e., the first distance, is shorter than the horizontal distance between the third arm or hand connected to the second arm relative to the second arm, i.e., the third rotation center and the second rotation center, i.e., the second distance. Therefore, the length of the first arm can be shortened.

[0011] Therefore, in this invention, even if the upper end of the arm lifting mechanism is positioned to the side of the base end of the first arm when the arm is lowered to the lower limit position, it is possible to position the upper end of the arm lifting mechanism to the side of the shorter first arm. As a result, the horizontal multi-joint robot can be miniaturized in the horizontal direction. That is, in this invention, even without changing the height of the horizontal multi-joint robot when the arm is lowered to the lower limit position, the lifting range of the arm can be increased, and the horizontal multi-joint robot can be miniaturized in the horizontal direction.

[0012] In this invention, for example, the arm lifting mechanism includes a ball screw for lifting the arm and a guide rail for guiding the arm in the vertical direction. The ball screw shaft is configured such that the axial direction of the screw shaft is aligned with the vertical direction, and the guide rail is configured such that the length direction of the guide rail is aligned with the vertical direction. When the arm is lowered to the lower limit position, the upper ends of the screw shaft and the guide rail are positioned to the side of the base end of the first arm.

[0013] In this invention, it is preferable that when the arm descends to the lower limit position, the upper end of the arm lifting mechanism is positioned lower than the lower end of the second arm. With this configuration, even if no cutouts or other features are formed on the second arm to prevent interference between the second arm and the arm lifting mechanism, interference between the second arm and the arm lifting mechanism during rotation can be prevented.

[0014] In this invention, for example, if the length direction of the first and second arms, when arranged in an overlapping state relative to the main body at a predetermined reference position, is defined as the arm length direction, one side of the arm length direction is defined as the first direction side, and the opposite side of the first direction side is defined as the second direction side, then when the first and second arms are arranged in an overlapping state relative to the main body at the reference position and the arm is lowered to the lower limit position, the base end of the first arm becomes the end of the first direction side of the first arm and is arranged on the second direction side of the upper end of the arm lifting mechanism, and the front end of the second arm becomes the end of the first direction side of the second arm and is arranged on the upper side of the arm lifting mechanism. In this case, even without changing the height of the horizontal multi-joint robot when the arm is lowered to the lower limit position, the lifting amount of the arm can be increased, and the horizontal multi-joint robot can be miniaturized in the arm length direction.

[0015] In this invention, it is preferable that the lifting mechanism is housed inside the main body, and that the first directional end of the second arm, when the first and second arms are overlapped and positioned relative to the main body at a reference position, is positioned in the same direction as the first directional end of the main body along the arm's length. With this configuration, the lifting range of the arm can be increased without changing the height of the horizontal multi-joint robot when the arm descends to its lower limit position, and the horizontal multi-joint robot can be further miniaturized along its arm's length.

[0016] In this invention, for example, the base end of the third arm is rotatably connected to the front end of the second arm, and the base end of the hand is rotatably connected to the front end of the third arm.

[0017] In this invention, a preferred horizontal joint robot includes: a first arm drive mechanism that rotates the first arm relative to the main body; a second arm drive mechanism that rotates the second arm relative to the first arm; a third arm drive mechanism that rotates the third arm relative to the second arm; and a hand drive mechanism that rotates the hand relative to the third arm. This configuration increases the degrees of freedom of movement for the horizontal joint robot.

[0018] As described above, in this invention, in a horizontal multi-joint robot whose arm moves in the horizontal direction, even without changing the height of the horizontal multi-joint robot when the arm descends to the lower limit position, the lifting range of the arm can be increased, and the horizontal multi-joint robot can be miniaturized in the horizontal direction. Attached Figure Description

[0019] Figure 1 This is a top view illustrating the structure of a horizontal multi-joint robot according to an embodiment of the present invention. Figure 2 yes Figure 1 The image shows a top view of a horizontally articulated robot in different states. Figure 3 yes Figure 2 The image shows a side view of a horizontal multi-jointed robot. Figure 4 yes Figure 3 The image shows a side view of a horizontal multi-joint robot with its arm raised. Figure 5 It is used for explanation Figure 2 The diagram shows the structure of a horizontal multi-joint robot. Figure 6 It is used from Figure 3 The diagram illustrates the structure of the boom lifting mechanism in the EE direction. (Symbol Explanation) 1. Robot (Horizontal Joint Robot) 2. Wafer (semiconductor wafer, object to be transported) 11 Hands 12 arms 13 Main body 15 First Arm 16 Second Arm 17 Third Arm 20-arm lifting mechanism 21 First arm drive mechanism 22 Second arm drive mechanism 23 Third Arm Drive Mechanism 24-hand drive mechanism 28 ball screw 29 lead screw shaft 31 guide rail C1 First Rotation Center C2 Second Rotation Center C3 Third Rotation Center D1 First Distance D2 Second Distance Y-arm length direction Y1 Second Direction Side Y2 First Direction Side Detailed Implementation

[0020] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0021] (Structure of a horizontal multi-joint robot) Figure 1 This is a top view illustrating the structure of a horizontal multi-joint robot 1 according to an embodiment of the present invention. Figure 2 yes Figure 1 Top views of the horizontal multi-jointed robot 1 in different states are shown. Figure 3 yes Figure 2 The side view of the horizontal multi-joint robot 1 shown. Figure 4 yes Figure 3 The side view of the horizontal multi-joint robot 1 with its arm 12 raised. Figure 5 It is used for explanation Figure 2 The diagram shows a block diagram of the structure of the horizontal multi-joint robot 1. Figure 6 It is used from Figure 3 The diagram illustrates the structure of the boom lifting mechanism 20 in the EE direction.

[0022] The horizontal articulated robot 1 (hereinafter referred to as "robot 1") of this embodiment is an industrial robot used for transporting a semiconductor wafer 2 (hereinafter referred to as "wafer 2"), which is the object to be transported. The wafer 2 is formed into a thin circular plate. Robot 1 is assembled and used in a semiconductor manufacturing system 3. In the following description, the direction orthogonal to the vertical direction will be referred to as the vertical direction. Figure 1 The X-direction of the equation is set to the "left-right direction", which is orthogonal to the up-down and left-right directions. Figure 1 The Y-direction of the equation is set as the "front-back direction". Additionally, one side of the front-back direction... Figure 1 The Y1 direction side is taken as the "front" side, and its opposite side is... Figure 1 The Y2 direction side is taken as the "back" side.

[0023] Semiconductor manufacturing system 3 includes EFEM4. Robot 1 is part of EFEM4. EFEM4 has, for example, multiple loading ports 7 for opening and closing FOUP6 ​​for housing wafers 2 and a housing 8 for housing robot 1. Housing 8 is formed as a cuboid box. When viewed from above, housing 8 has an elongated rectangular shape in the left-right direction. Multiple loading ports 7 are, for example, arranged on the front side of housing 8. In addition, multiple loading ports 7 are arranged at intervals in the left-right direction.

[0024] Robot 1 includes: two hands 11 equipped with a chip 2; an arm 12 rotatably connected to the front end of the two hands 11 and movable in the horizontal direction; and a main body 13 rotatably connected to the base end of the arm 12. The hands 11 are formed into a roughly Y-shape when viewed from above. The arm 12 is composed of a first arm 15 rotatably connected to the main body 13 from the base end, a second arm 16 rotatably connected to the front end of the first arm 15 from the base end, and a third arm 17 rotatably connected to the front end of the second arm 16 from the base end. The base ends of the two hands 11 are rotatably connected to the front end of the third arm 17. The base ends of the two hands 11 overlap in the vertical direction.

[0025] The hand 11, first arm 15, second arm 16, and third arm 17 rotate along an axis with the vertical direction as the axis of rotation. The upper and lower surfaces of the first arm 15, second arm 16, and third arm 17 form planes orthogonal to the vertical direction. The first arm 15 is connected to the upper surface of the main body 13. The second arm 16 is connected to the upper surface of the first arm 15. The third arm 17 is connected to the upper surface of the second arm 16. The hand 11 is connected to the upper surface of the third arm 17.

[0026] Specifically, the lower surface of the first arm 15 is connected to the upper surface of the main body 13, the lower surface of the second arm 16 is connected to the upper surface of the first arm 15, the lower surface of the third arm 17 is connected to the upper surface of the second arm 16, and the lower surface of the hand 11 is connected to the upper surface of the third arm 17. The second arm 16 is positioned above the first arm 15, the third arm 17 is positioned above the second arm 16, and the hand 11 is positioned above the third arm 17.

[0027] Furthermore, the robot 1 includes: an arm lifting mechanism 20 for raising and lowering the arm 12; a first arm drive mechanism 21 for rotating the first arm 15 relative to the main body 13; a second arm drive mechanism 22 for rotating the second arm 16 relative to the first arm 15; a third arm drive mechanism 23 for rotating the third arm 17 relative to the second arm 16; and a hand drive mechanism 24 for rotating the hand 11 relative to the third arm 17. The robot 1 of this embodiment has two hand drive mechanisms 24 that allow each of the two hands 11 to rotate independently.

[0028] The rotation centers of the two hands 11 relative to the third arm 17 are the same. If we define the rotation center of the first arm 15 relative to the main body 13 as the first rotation center C1, the rotation center of the second arm 16 relative to the first arm 15 as the second rotation center C2, the rotation center of the third arm 17 relative to the second arm 16 as the third rotation center C3, and the rotation center of the hand 11 relative to the third arm 17 as the fourth rotation center C4, then the horizontal distance between the first rotation center C1 and the second rotation center C2 (i.e., the first distance D1) is shorter than the horizontal distance between the second rotation center C2 and the third rotation center C3 (i.e., the second distance D2). Furthermore, the second distance D2 is shorter than the horizontal distance between the third rotation center C3 and the fourth rotation center C4 (i.e., the third distance D3).

[0029] Therefore, in this embodiment, the length of the first arm 15 (the length of the first arm 15 in the length direction) is shorter than the length of the second arm 16 (the length of the second arm 16 in the length direction), and the length of the second arm 16 is shorter than the length of the third arm 17 (the length of the third arm 17 in the length direction).

[0030] The main body 13 includes a housing 26 and a lifting body 27, with the base end of the first arm 15 rotatably connected to the lifting body 27. The housing 26 is generally formed into a long, narrow cuboid shape in the vertical direction. A protrusion 26a is formed at the rear end of the housing 26, protruding upwards. That is, the height of the rear end of the housing 26 is higher than the height of the front part of the housing 26. The protrusion 26a is positioned further rearward than the base end of the first arm 15. The upper surface of the protrusion 26a is a plane orthogonal to the vertical direction. In addition, the upper surface of the portion of the housing 26 forward of the protrusion 26a is also a plane orthogonal to the vertical direction. The height of the protrusion 26a relative to the upper surface of the front part of the housing 26 is approximately equal to the thickness (vertical thickness) of the first arm 15.

[0031] The lifting body 27 can move up and down relative to the housing 26. For example... Figure 3As shown, when the arm 12 descends to its lower limit position, most of the lifting body 27 is housed inside the housing 26. The lifting body 27 has a lifting body main body 27a and a retaining portion 27b. The lifting body main body 27a is rotatably connected to the base end of the first arm portion 15 at its upper end, and the retaining portion 27b protrudes rearward from the lower end of the lifting body main body 27a. The lifting body main body 27a is positioned forward of the protrusion 26a of the housing 26. The upper end of the lifting body main body 27a is positioned on the upper surface of the portion of the housing 26 forward of the protrusion 26a. A through hole is formed at the upper end of the portion of the housing 26 forward of the protrusion 26a, through which a portion of the lifting body main body 27a is disposed.

[0032] The boom lifting mechanism 20 raises and lowers the lifting body 27. That is, the boom lifting mechanism 20 raises and lowers the lifting body 27, thereby causing the boom 12 and the lifting body 27 to rise and fall together. Furthermore, the boom lifting mechanism 20... Figure 3 The lower limit position of arm 12 shown is... Figure 4 The upper limit position of the arm 12, as shown, allows the arm 12 to rise and fall together with the lifting body 27. For example... Figure 6 As shown, the arm lifting mechanism 20 includes: a ball screw 28 for raising and lowering the arm 12 together with the lifting body 27; a motor 30 for rotating the screw shaft 29 of the ball screw 28; and a guide rail 31 and a guide block 32 for guiding the arm 12 in the vertical direction together with the lifting body 27. The arm lifting mechanism 20 is disposed inside the housing 26. That is, the arm lifting mechanism 20 is housed inside the main body 13.

[0033] The lead screw shaft 29 is configured such that its axial direction aligns with the vertical direction. The lead screw shaft 29 is rotatably held on a frame disposed inside the housing 26. The nut component 33 of the ball screw 28 is mounted on the retaining part 27b of the lifting body 27. The nut component 33 engages with the lead screw shaft 29. A pulley 35 is fixed to the lower end of the lead screw shaft 29. The motor 30 is fixed inside the housing 26. A pulley 36 is fixed to the output shaft of the motor 30. A belt 37 is mounted on the pulleys 35 and 36. The motor 30 is electrically connected to the control unit 38 of the robot 1.

[0034] The guide rail 31 is arranged such that its length direction is aligned with its vertical direction. The guide rail 31 is fixed to a frame disposed inside the housing 26. In this embodiment, two guide rails 31 are arranged with a distance between them in the left-right direction. A guide block 32 is mounted on the holding portion 27b of the lifting body 27. The guide block 32 engages with the guide rail 31 from the front. Furthermore, in this embodiment, two guide blocks 32 arranged with a distance between them in the vertical direction engage with one guide rail 31.

[0035] As described above, the arm lifting mechanism 20 is disposed inside the housing 26. Specifically, the arm lifting mechanism 20 is disposed inside the rear end of the housing 26. Furthermore, the upper end of the arm lifting mechanism 20 is disposed inside the protrusion 26a. Specifically, the upper ends of the lead screw 29 and the guide rail 31 are disposed inside the protrusion 26a. Additionally, when the arm 12 rises to its upper limit position, the upper guide block 32 of the two guide blocks 32 that engage with one guide rail 31 is disposed inside the protrusion 26a (see reference). Figure 4 ).

[0036] Furthermore, as described above, the boom lifting mechanism 20 causes the boom 12 and the lifting body 27 to move together. Figure 3 The lower limit position of arm 12 shown is... Figure 4 The arm 12 shown rises and falls between its upper limit position. When the arm 12 descends to its lower limit position, the first arm portion 15 is positioned vertically at approximately the same location as the protrusion 26a of the housing 26, with the upper surface of the protrusion 26a positioned above the lower surface of the first arm portion 15. Furthermore, when the arm 12 descends to its lower limit position, the base of the first arm portion 15 is positioned in front of the protrusion 26a.

[0037] That is, when the arm 12 descends to the lower limit position, the upper end of the arm lifting mechanism 20 (specifically, the upper end of the lead screw 29 and the guide rail 31) disposed inside the protrusion 26a is positioned behind (rearward) the base end of the first arm 15. That is, when the arm 12 descends to the lower limit position, the upper end of the arm lifting mechanism 20 (specifically, the upper end of the lead screw 29 and the guide rail 31) is positioned laterally (laterally) to the base end of the first arm 15. Furthermore, when the arm 12 descends to the lower limit position, the upper end of the arm lifting mechanism 20 (specifically, the upper end of the lead screw 29 and the guide rail 31) is positioned above the lower surface of the first arm 15.

[0038] Furthermore, when arm 12 descends to its lower limit position, the upper surface of the first arm portion 15 is positioned slightly above the upper surface of the protrusion 26a. Additionally, when arm 12 descends to its lower limit position, the lower surface of the second arm portion 16 is positioned above the upper surface of the protrusion 26a. In other words, when arm 12 descends to its lower limit position, the upper end of the arm lifting mechanism 20 is positioned lower than the lower end of the second arm portion 16.

[0039] In this embodiment, when the first arm portion 15 and the second arm portion 16 are arranged at a predetermined reference position relative to the main body portion 13 in an overlapping state ( Figures 2-4In the state shown, the length direction of the first arm portion 15 and the second arm portion 16 is consistent with the front-rear direction. Furthermore, when the first arm portion 15 and the second arm portion 16 are arranged relative to the main body portion 13 at a reference position with their ends overlapping each other and the arm 12 is lowered to its lower limit position, the front end of the second arm portion 16 becomes the rear end of the second arm portion 16, and is arranged above the protrusion 26a (see reference). Figure 3 ).

[0040] That is, when the first arm portion 15 and the second arm portion 16 are arranged in a reference position relative to the main body portion 13 in an overlapping state and the arm 12 is lowered to the lower limit position, the front end of the second arm portion 16 is arranged on the upper side of the arm lifting mechanism 20. Furthermore, at this time, the base end of the first arm portion 15 becomes the rear end of the first arm portion 12, and is arranged on the front side of the upper end of the arm lifting mechanism 20. Additionally, as... Figure 3 As shown, when the first arm 15 and the second arm 16 are arranged in a reference position relative to the main body 13 in an overlapping state, the rear end of the second arm 16 is arranged in the front-rear direction at the same position as the rear end of the main body 13 (specifically, the rear surface of the housing 26).

[0041] In this embodiment, the front-back direction (Y direction) is the length direction of the first arm 15 and the second arm 16 when they are arranged in a reference position relative to the main body 13 in an overlapping state. The rear side (Y2 direction side) is one side of the arm length direction, i.e., the first direction side, and the front side (Y1 direction side) is the opposite side of the first direction side, i.e., the second direction side.

[0042] The first arm drive mechanism 21 includes a motor 39. The motor 39 is mounted on the lifting body 27. The power of the motor 39 is transmitted to the first arm 15 through a power transmission mechanism consisting of a reducer, pulleys, and belts. The second arm drive mechanism 22 includes a motor 40. The motor 40 is mounted at the connection between the first arm 15 and the lifting body 27. The power of the motor 40 is transmitted to the second arm 16 through a power transmission mechanism consisting of a reducer, pulleys, and belts.

[0043] The third arm drive mechanism 23 has a motor 41. The motor 41 is installed inside the second arm 16. The power of the motor 41 is transmitted to the third arm 17 via a power transmission mechanism consisting of a reducer, pulleys, and belts. The hand drive mechanism 24 has a motor 42. The motor 42 is installed inside the third arm 17. The power of the motor 42 is transmitted to the hand 11 via a power transmission mechanism consisting of a reducer, pulleys, and belts.

[0044] Motors 39-42 are electrically connected to the control unit 38. In this embodiment, when the hand 11, which is approximately Y-shaped when viewed from above, moves in the left-right direction with its length direction aligned with the front-back direction, the control unit 38 controls motors 39-42 to rotate the first arm 15, the second arm 16, the third arm 17, and the hand 11, so that the third rotation center C3 passes through an imaginary line VL (see reference) that is parallel to the left-right direction when viewed from above. Figure 1 )superior.

[0045] That is, when the length direction of the hand 11 is aligned with the front-back direction and the hand 11 moves in the left-right direction, the control unit 38 rotates the first arm 15, the second arm 16, the third arm 17, and the hand 11, so that when viewed from the top-bottom direction, the third rotation center C3 moves linearly in the left-right direction. At this time, the control unit 38 rotates the first arm 15, the second arm 16, the third arm 17, and the hand 11 so that the hand 11 and arm 12 do not interfere with the housing 8.

[0046] (Main effects of this implementation method) As described above, in this embodiment, when the arm 12 descends to the lower limit position, the upper end of the arm lifting mechanism 20, which is disposed inside the protrusion 26a, is disposed behind the base end of the first arm portion 15. Therefore, in this embodiment, compared to the case where the entire arm lifting mechanism 20 is disposed below the first arm portion 15, the height of the arm lifting mechanism 20 can be increased without changing the height of the robot 1 when the arm 12 descends to the lower limit position. That is, in this embodiment, the vertical length of the lead screw shaft 29 and the guide rail 31 can be increased without changing the height of the robot 1 when the arm 12 descends to the lower limit position. Therefore, in this embodiment, the lifting amount of the arm 12 can be increased without changing the height of the robot 1 when the arm 12 descends to the lower limit position.

[0047] Furthermore, in this embodiment, the horizontal distance between the first arm 15 and the first rotation center C1 relative to the main body 13, and the second arm 16 and the second rotation center C2 relative to the first arm 15, is the first distance D1, which is shorter than the horizontal distance between the third arm 17 and the second arm 16, which is the third rotation center D3 and the second rotation center D2, which is the second distance D2. The length of the first arm 15 is shorter than the length of the second arm 16.

[0048] Therefore, in this embodiment, even if the upper end of the arm lifting mechanism 20 is positioned behind the base end of the first arm 15 when the arm 12 is lowered to the lower limit position, the upper end of the arm lifting mechanism 20 can still be positioned behind the shorter first arm 15. As a result, the robot 1 can be miniaturized in the front-back direction. That is, in this embodiment, even if the height of the robot 1 when the arm 12 is lowered to the lower limit position is not changed, the lifting amount of the arm 12 can be increased, and the robot 1 can be miniaturized in the front-back direction.

[0049] Furthermore, in this embodiment, when the first arm 15 and the second arm 16 overlap each other, the rear end of the second arm 16, which is positioned relative to the main body 13 at a reference position, is positioned in the same position as the rear end of the main body 13 in the front-back direction. Therefore, even without changing the height of the robot 1 when the arm 12 is lowered to the lower limit position, the lifting amount of the arm 12 can be increased, and the robot 1 can be further miniaturized in the front-back direction.

[0050] In this embodiment, when the arm 12 descends to the lower limit position, the lower surface of the second arm portion 16, which becomes the lower end of the second arm portion 16, is positioned higher than the upper surface of the protrusion 26a of the housing 26. Therefore, in this embodiment, even if a cutout or similar feature is not formed on the second arm portion 16 to prevent interference between the protrusion 26a at the upper end of the storage arm lifting mechanism 20 and the second arm portion 16, interference between the second arm portion 16 and the protrusion 26a during rotation can still be prevented.

[0051] In this embodiment, robot 1 includes: a first arm drive mechanism 21 that rotates the first arm 15 relative to the main body 13; a second arm drive mechanism 22 that rotates the second arm 16 relative to the first arm 15; a third arm drive mechanism 23 that rotates the third arm 17 relative to the second arm 16; and a hand drive mechanism 24 that rotates the hand 11 relative to the third arm 17. Therefore, in this embodiment, the degree of freedom of movement of robot 1 can be improved.

[0052] (Other implementation methods) The above-described embodiments are examples of preferred embodiments of the present invention, but are not limited thereto. Various modifications can be made without changing the spirit of the present invention.

[0053] In the above embodiment, when the first arm portion 15 and the second arm portion 16 are arranged in a reference position relative to the main body portion 13 in an overlapping state, the rear end of the second arm portion 16 can be arranged in a position forward of the rear end of the main body portion 13, or it can be arranged in a position rearward of the rear end of the main body portion 13. Furthermore, in the above embodiment, when the arm 12 descends to the lower limit position, the lower end of the second arm portion 16 can also be arranged below the upper surface of the protrusion 26a of the housing 26. In this case, a cutout or the like is formed in the second arm portion 16 to prevent interference between the protrusion 26a and the second arm portion 16.

[0054] In the above embodiment, arm 12 may also be composed of two arm portions: a first arm portion 15 and a second arm portion 16. In this case, the base of hand portion 11 is rotatably connected to the front end of second arm portion 16. Furthermore, in this case, the horizontal distance between the third rotation center and the second rotation center C2 of hand portion 11 relative to second arm portion 16, i.e., the second distance, is longer than the first distance D1. Additionally, in the above embodiment, arm 12 may also be composed of four or more arm portions.

[0055] In the above embodiments, the arm lifting mechanism 20 can also replace the guide rail 31 and guide block 32, for example, by having a guide shaft and a cylindrical guide bushing through which the guide shaft passes. Additionally, in the above embodiments, the arm lifting mechanism 20 can also replace the ball screw 28, for example, by having a belt partially fixed to the holding portion 27b of the lifting body 27 and a pulley supporting the belt. Furthermore, in the above embodiments, the number of hands 11 rotatably connected to the front end of the arm 12 can also be one. Furthermore, in the above embodiments, the object transported by the robot 1 can also be an object other than the wafer 2. In this case, for example, the object transported can be formed into a square or rectangular flat plate.

Claims

1. A horizontal multi-joint robot, wherein the arm of the horizontal multi-joint robot moves in a horizontal direction. Its features are, include: A hand that carries an object; an arm that is rotatably connected to the hand at its front end; The main body portion is rotatably connected to the base end side of the arm; And the arm lifting mechanism that raises and lowers the arm, The arm includes: a first arm portion rotatably connected to the main body portion at its base end; and a second arm portion rotatably connected to the front end of the first arm portion at its base end. The lower surface of the first arm is connected to the upper surface of the main body. The lower surface of the second arm is connected to the upper surface of the first arm. The base end of a third arm portion, which forms part of the arm, or the base end of the hand portion, is rotatably connected to the front end of the second arm portion. The first distance is shorter than the second distance, wherein the first distance is the horizontal distance between a first rotation center (which is the rotation center of the first arm relative to the main body) and a second rotation center (which is the rotation center of the second arm relative to the first arm), and the second distance is the horizontal distance between the third rotation center (which is the rotation center of the third arm or the hand connected to the second arm relative to the second arm) and the second rotation center. When the arm descends to its lower limit position, the upper end of the arm lifting mechanism is positioned to the side of the base end of the first arm. If the length direction of the first arm and the second arm, when arranged in an overlapping state relative to the main body at a predetermined reference position, is defined as the arm length direction, then one side of the arm length direction is defined as the first direction side, and the opposite side of the first direction side is defined as the second direction side. When the first arm and the second arm are arranged relative to the main body at the reference position in an overlapping state and the arm is lowered to the lower limit position, the base end of the first arm becomes the end of the first direction side of the first arm and is arranged on the second direction side of the upper end of the arm lifting mechanism, and the front end of the second arm becomes the end of the first direction side of the second arm and is arranged on the upper side of the arm lifting mechanism.

2. The horizontal multi-joint robot according to claim 1, characterized in that, The arm lifting mechanism includes: a ball screw for raising and lowering the arm; and a guide rail for guiding the arm in the vertical direction. The ball screw shaft is configured such that its axial direction is aligned with the vertical direction. The guide rail is configured such that its length direction is consistent with its vertical direction. When the arm descends to the lower limit position, the upper ends of the lead screw and the guide rail are positioned to the side of the base end of the first arm.

3. The horizontal multi-joint robot according to claim 1 or 2, characterized in that, When the arm descends to the lower limit position, the upper end of the arm lifting mechanism is positioned lower than the lower end of the second arm.

4. The horizontal multi-joint robot according to claim 1, characterized in that, The lifting mechanism is housed inside the main body. With the first arm and the second arm overlapping each other, the first directional end of the second arm, which is positioned relative to the main body at the reference position, is positioned in the same position as the first directional end of the main body in the arm length direction.

5. The horizontal multi-joint robot according to claim 1 or 2, characterized in that, The base end of the third arm is rotatably connected to the front end of the second arm. The base end of the hand is rotatably connected to the front end of the third arm.

6. The horizontal multi-joint robot according to claim 5, Its features are, It includes: a first arm drive mechanism for rotating the first arm relative to the main body; a second arm drive mechanism for rotating the second arm relative to the first arm; a third arm drive mechanism for rotating the third arm relative to the second arm; and a hand drive mechanism for rotating the hand relative to the third arm.

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