Transport robot

Abstract

The objective is to provide a transport robot that reduces the limitations on the range of motion of the hand unit used for transporting workpieces. [Solution] The arm unit 20 of the transport robot 100 has an R-axis motor 31 that rotates the second arm 22 relative to the first arm 21. The R-axis motor 31 is fixed protruding from the lower side of the arm axis holding portion 212 of the first arm 21 with its output shaft facing upward, and the output shaft passes through the first arm 21 from below, and the output shaft is fixed to the second arm 22 by an axis fixing portion 50.

Description

Technical Field

[0001] The present invention relates to the technology of a transport robot having a hand part for transporting a workpiece.

Background Art

[0002] Patent Document 1 describes a transport robot provided with an articulated arm unit. The transport robot can change the position of a hand part for transporting a workpiece by controlling the relative positions of the respective arms constituting the arm unit by means of motors, and can transport the workpiece. Further, in the transport robot described in Patent Document 1, the motors for rotating the arms are housed within joints that connect the arms to each other.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a transport robot, when the dimension in the height direction of the arm unit becomes large, the operating range of the hand part may be restricted. For example, as the dimension in the height direction of the arm unit becomes larger, the position of the hand part in the height direction becomes higher with respect to the base, thus restricting the operating range of the hand part.

[0005] The present invention has been made in view of the above problems, and an object thereof is to provide a transport robot that reduces the restriction on the operating range of a hand part for transporting a workpiece.

Means for Solving the Problems

[0006] To solve the above problems, the transport robot according to the present invention comprises a multi-joint arm unit that changes the position of a hand for transporting a workpiece, and a base unit. The arm unit has a first arm supported by a first joint located at one end so as to be rotatable horizontally relative to the base unit, a second arm located above the first arm and supported by a second joint located at the other end of the first arm so as to be rotatable horizontally relative to the first arm, and a rotation motor that rotates the second arm at the second joint. The rotation motor is fixed protruding from the lower side of the second joint of the first arm with its output shaft facing upward, the output shaft passes through the first arm from below, and the output shaft is fixed to the second arm, and in accordance with the rotation of the output shaft, the second arm is rotated horizontally relative to the first arm at the second joint.

[0007] In the above configuration, the rotary motor that rotates the second arm horizontally at the second joint relative to the first arm is fixed to the underside of the second joint in the first arm with its output shaft facing upward. The rotary motor's output shaft passes through the first arm from below, and the output shaft is fixed to the second arm. This makes it possible to suppress the increase in the height dimension of the first arm, regardless of the size of the rotary motor, compared to the case where the rotary motor is housed within the second joint connecting the first and second arms. As a result, it is possible to suppress the increase in the height dimension of the arm unit and reduce the limitations on the range of motion of the hand.

[0008] The base unit comprises a fixed base and a lifting base connected to the first arm at a first joint, which is movable up and down in the height direction from the fixed base. This allows the lifting stroke, which is the range of motion of the hand unit in the height direction, to be expanded to a desired value.

[0009] When L is the distance from the pivot center of the first joint to the pivot center of the second joint in the first arm, the base is located inward in the horizontal direction, within a radius L range relative to the pivot center of the first joint. When the hand is at its lowest position in the height direction due to the lifting base, the rotation motor does not interfere with the upper end of the fixed base. This makes it possible to reduce the limitations on the range of motion of the hand while ensuring clearance between the first arm and the fixed base.

[0010] The arm unit comprises an arm shaft portion extending downward from one end of the second arm, a shaft holding portion located on the other end of the first arm and having a recess into which the arm shaft portion is inserted, and an arm bearing within the shaft holding portion that holds the arm shaft portion so as to be rotatable in the horizontal direction. The arm shaft portion, shaft holding portion, and arm bearing constitute the second joint, and the rotation motor is detachably fixed to the underside of the shaft holding portion on the first arm. This allows the rotation motor to be removed from the arm unit without disconnecting the first arm and the second arm. As a result, the maintainability of the rotation motor in the transport robot can be improved. [Effects of the Invention]

[0011] According to the present invention, it is possible to provide a transport robot that has fewer limitations on the range of motion of the hand portion for transporting workpieces. [Brief explanation of the drawing]

[0012] [Figure 1] This is a perspective view of a transport robot. [Figure 2] This is a front view of a transport robot. [Figure 3] This is a cross-sectional view taken along the line A-A in Figure 2. [Figure 4] This is a block diagram of the transport system. [Figure 5] This diagram illustrates the operating range of a transport robot. [Figure 6] This diagram illustrates the operating range of a transport robot. [Modes for carrying out the invention]

[0013] (First Embodiment) The transport system according to this embodiment will be described with reference to the drawings. The transport system consists of a transport robot and a control device that controls the drive of the transport robot. The transport system is a device that transports a wafer, which is a workpiece, using the transport robot.

[0014] Figures 1, 2, and 3 show the transport robot 100 in a position where it is not transporting wafers, specifically in its home position. The transport robot 100 comprises a base unit 10 and an arm unit 20, and is a device that changes the position of the hand unit, which will be described later, within a predetermined range of motion by driving the arm unit 20.

[0015] In the transport robot 100, the direction horizontal to the mounting surface on which the base unit 10 is placed is described as the horizontal direction. In the transport robot 100, the vertical direction is described as the height direction D1. Within the horizontal direction, the direction in which the arm unit 20 of the transport robot 100 extends in the home position is described as the extension direction D2, and the direction intersecting the extension direction D2 is described as the width direction D3. In other words, the extension direction D2 and the width direction D3 are also directions that intersect each other in the horizontal direction.

[0016] The base unit 10 includes a fixed base 11, a lifting base 12, and a lifting drive unit 13 (Figure 3). The fixed base 11 consists of a pedestal 14 and a vertical column 15 extending from the pedestal 14 in the height direction D1. The pedestal 14 is a member for fixing the transport robot 100 to a mounting surface at a predetermined location (for example, a wafer transport chamber, which will be described later). The pedestal 14 is a rectangular member in top view, having a bottom surface 14A and an upper surface 14B located on the opposite side of the bottom surface 14A, and is fixed to the mounting surface, for example, by bolts.

[0017] The vertical column 15 is composed of a pair of first column parts 16 and a second column part 17. The positions of the first column part 16 and the second column part 17 in the vertical column 15 are determined so as not to interfere with the arm unit 20 when the arm unit 20 rotates and moves up and down within the operating range. The pair of first column parts 16 are plate-shaped members and are arranged side by side in the width direction D3 with respect to the pedestal 14. Specifically, as shown in FIG. 2, the pair of first column parts 16 extend from the pedestal 14 with their surfaces facing the width direction D3. The second column part 17 is a part that extends from the pedestal 14 on the left side of the paper surface with respect to the pair of first column parts 16 in the extending direction D2. The second column part 17 has a central wall facing the extending direction D2 and a pair of side walls extending at both ends of this central part, and is a U-shaped member in a top view by the central wall and the side walls.

[0018] The lifting base 12 is supported by the lifting drive part 13 so as to be able to move up and down in the height direction D1 with respect to the fixed base 11. The arm unit 20 is connected to the upper part of the lifting base 12. FIG. 3 is a cross-sectional view taken along the A-A arrow in FIG. 2. As shown in FIG. 3, the lifting drive part 13 has a Z-axis motor 130, a Z-axis belt 131, a linear guide 132, and a ball screw 133.

[0019] In the fixed base 11, in the second column portion 17, a rail portion 132B constituting the linear guide 132 and a ball screw shaft portion 133B constituting the ball screw 133 are arranged along the height direction D1 of the extending direction thereof. The linear block 132A constituting the linear guide 132 is guided by the rail portion 132B and is screwed to the ball screw nut portion 133A via the lifting base 12. On the pedestal 14 of the fixed base 11, a Z-axis motor 130 is mounted with its output shaft facing downward. The output shaft of the Z-axis motor 130 and the ball screw shaft portion 133B are connected via a Z-axis belt 131 which is an endless belt, and the rotation of the output shaft of the Z-axis motor 130 is converted by the Z-axis belt 131 into the rotation of the ball screw shaft portion 133B. Incidentally, the Z-axis motor 130 may be mounted on the fixed base 11 with its output shaft facing upward. Even in this case, the output shaft of the Z-axis motor 130 may be connected to the ball screw shaft portion 133B via the Z-axis belt 131.

[0020] Due to the rotation of the output shaft of the Z-axis motor 130, the ball screw shaft portion 133B rotates to raise and lower the ball screw nut portion 133A. In response to the raising and lowering of the ball screw nut portion 133A, the linear block 133A raises and lowers while being guided by the rail portion 132B, and the lifting base 12 raises and lowers in the height direction D1.

[0021] An arm unit 20 is connected to the upper part of the lifting base 12. The arm unit 20 has a first arm 21, a second arm 22, a hand arm 23, a drive unit 24, a T-axis motor 30, and an R-axis motor 31. The arm unit 20 rotates the first arm 21 horizontally with respect to the base portion 10 in the direction in which the output shaft of the T-axis motor 30 rotates (hereinafter referred to as the rotation direction of the T-axis), and rotates the second arm 22 horizontally with respect to the first arm 21 in the direction in which the output shaft of the R-axis motor 31 rotates (hereinafter referred to as the rotation direction of the R-axis). The arm unit 20 rotates the hand arm 23 horizontally with respect to the second arm 22 in the direction in which pulleys 241 and 244 of the drive unit 24 described later rotate (hereinafter referred to as the rotation direction of the H-axis).

[0022] Next, the detailed configuration of the arm unit 20 will be described. The T-axis motor 30 is a motor that rotates the first arm 21 of the arm unit 20 in the horizontal direction (the rotation direction of the T-axis). As shown in Figure 3, the T-axis motor 30 is fixed to the upper part of the lifting base 12 with its output shaft 301 facing upward in the height direction D1. In this embodiment, the T-axis motor 30 is an AC motor. Alternatively, the T-axis motor 30 may be a DC motor.

[0023] The first arm 21 is a long, elongated member having a T-axis holding portion 211 located at one end, an arm axis holding portion 212 located at the other end, and an extension portion 210 extending between the T-axis holding portion 211 and the arm axis holding portion 212. The first arm 21 is fixed to the output shaft 301 of the T-axis motor 30 at the T-axis holding portion 211 and connected to the second arm 22 at the arm axis holding portion 212. The arm axis holding portion 212 is a portion having a circular recess in a top view, and has an opening 213 that penetrates through in the height direction D1 at the center of the recess. The inner diameter of the opening 213 is larger than the diameter of the output shaft of the R-axis motor 31, which will be described later, and the output shaft of the R-axis motor 31 can pass through it.

[0024] The second arm 22 is an elongated member having an arm shaft portion 221 located at one end, a pulley holding portion 222 located at the other end, and an extension portion 220 extending between the arm shaft portion 221 and the pulley holding portion 222. The extension portion 220 is hollow and has a space inside which the drive unit 24 is housed. The arm shaft portion 221 is a substantially cylindrical portion that extends downward in the height direction D1 from one end of the extension portion 220. The arm shaft portion 221 has a diameter that allows it to be inserted into the recess of the arm shaft holding portion 212 of the first arm 21. The center of the arm shaft portion 221 has an opening 224 that penetrates in the height direction D1. The inner diameter of the opening 224 is larger than the diameter of the output shaft of the R-axis motor 31. The pulley holding portion 222 has an opening 225 that penetrates upward, and this opening 225 communicates with the space of the extension portion 220.

[0025] The arm shaft portion 221 of the second arm 22 is rotatably held within the arm shaft holding portion 212 of the first arm 21. Specifically, the arm shaft portion 221 is held in the arm shaft holding portion 212 via an arm bearing 34 located between the outer circumference of the arm shaft portion 221 and the inner circumference of the recess in the arm shaft holding portion 212. As a result, even when the R-axis motor 31 is removed from the first arm 21, the second arm 22 remains rotatably connected to the first arm 21 in the horizontal direction (the direction of rotation of the R-axis).

[0026] In this embodiment, as shown in Figure 2, the dimension H1 of the first arm 21 in the height direction D1 is smaller than the dimension H2 of the second arm 22 in the height direction D1. This allows for a higher ratio of the dimension H2 of the second arm 22, in which the drive unit 24 is located, to the height direction dimension of the arm unit 20.

[0027] An R-axis motor 31 is fixed to the lower surface of the arm shaft holding portion 212 of the first arm 21. The R-axis motor 31 has an output shaft 311, a case 312 that rotatably holds the output shaft 311, and motor-side bearings 313 and 314. The R-axis motor 31 is mounted on the lower surface of the arm shaft holding portion 212 with the output shaft 311 facing upward in the height direction D1. Specifically, the R-axis motor 31 is fixed to the lower surface of the arm shaft holding portion 212 by bolts with the upper surface of the case 312, with the output shaft 311 passing through the opening 213 of the arm shaft holding portion 212. The R-axis motor 31 is an AC motor, but a DC motor may be used instead. In this embodiment, the R-axis motor 31 is an example of a rotating motor.

[0028] The case 312 houses a rotor that generates a magnetic field for rotating the output shaft 311, and a rotary encoder which is a position detection unit. In this embodiment, the output shaft 311 is hollow with open ends in the direction in which it extends, and is rotatably held in the case 312 via motor-side bearings 313 and 314 which are arranged in the height direction.

[0029] The portion of the output shaft 311 of the R-axis motor 31 that penetrates the first arm 21 and extends upward is fixed to the second arm 22 by a shaft fixing part 50 within the second arm 22. The shaft fixing part 50 is a member that fixes the output shaft 311 to the second arm 22 by fastening the output shaft 311 in the radial direction of the output shaft 311. Specifically, the shaft fixing part 50 has a tapered fastening hole 51 whose inner diameter gradually decreases as it moves from bottom to top in the height direction D1. With the output shaft 311, which has penetrated the first arm 21, inserted into the fastening hole 51, the shaft fixing part 50 is tightened to the second arm 22 by a bolt inserted from above around the fastening hole 51, thereby fastening the output shaft 311 radially with the inner circumferential surface of the fastening hole 51.

[0030] The second arm 22 is connected to the hand arm 23 at the pulley holding portion 222 on its other end. In this embodiment, the hand arm 23 has an upper hand portion 231 and a lower hand portion 232 that are arranged vertically in the height direction D1. Each hand portion 231, 232 has a U-shaped mounting plate 231A, 232A, and a wafer can be placed on the mounting plates 231A, 232A.

[0031] Each hand section 231, 232 holds the wafer placed on the mounting plates 231A, 232A by vacuum suction. Each hand section 231, 232 only needs to be shaped to transport the wafer and is not limited to having mounting plates 231A, 232A. For example, each hand section 231, 232 may be configured to hold the wafer by a mechanical chuck.

[0032] The drive unit 24 located within the second arm 22 includes an upper pulley 241 that changes the horizontal position (i.e., the rotational direction of the H1 axis) of the upper hand portion 231 relative to the second arm 22, an upper motor 242, and an H1 axis belt 243 that connects the upper motor 242 and the upper pulley 241. The drive unit 24 also includes a lower pulley 244 that changes the horizontal position (i.e., the rotational direction of the H2 axis) of the lower hand portion 232 relative to the second arm 22, a lower motor 245, and an H2 axis belt 246 that connects the lower motor 245 and the lower pulley 244.

[0033] In the extension direction D2, if L is the distance from the output shaft 301, which is the rotation center of the T-axis motor 30, to the output shaft 311, which is the rotation center of the R-axis motor 31, then the base portion 10 is located inward in the horizontal direction, within the range of motion of radius L with respect to the output shaft 301 of the T-axis motor 30. In other words, even when the first arm 21 is rotated in the rotation direction of the T-axis, the base portion 10 of the transport robot 100 is in a position that does not interfere with the R-axis motor 31. Furthermore, when the first arm 21 is in its lowest position in the height direction due to the lifting base 12, the lower end of the first arm 21 is located above the upper end of the fixed base 11. In this embodiment, the "lowest position in the height direction" of the first arm 21 is the height direction position of the first arm 21 in the home position.

[0034] In this embodiment, the T-axis holding portion 211 of the first arm 21 and the output shaft 301 of the T-axis motor 30 are examples of the first joint. The arm shaft holding portion 212 of the first arm 21 and the arm shaft portion 221 of the second arm 22 are examples of the second joint.

[0035] Next, the electrical configuration of the transport robot 100 will be explained using Figure 4. As shown in Figure 4, the control device 70 is a device that controls the driving of each motor 30, 31, 130, 242, and 245 of the transport robot 100, and supplies power to each part that makes up the transport robot 100. The control device 70 has a main controller 71, a low-voltage power supply circuit 72, a high-voltage power supply circuit 73, and driver circuits 74A, 74B, 74C, 74D, and 74E. In Figure 4, the circuits through which power flows are shown by dashed lines.

[0036] The main controller 71 has a memory for storing programs and an arithmetic circuit for executing programs. The main controller 71 is connected to each of the driver circuits 74A to 74E and outputs drive signals to the driver circuits 74A to 74E to drive each motor.

[0037] The low-voltage power supply circuit 72 supplies power to the main controller 71 to drive the main controller 71. The low-voltage power supply circuit 72 is a well-known converter circuit that converts the AC voltage supplied from the AC power supply into a DC voltage and supplies it to the main controller 71.

[0038] The high-voltage power supply circuit 73 supplies power to each driver circuit 74A to 74E to drive each motor 30, 31, 130, 242, and 245. The high-voltage power supply circuit 73 is a well-known converter circuit that converts the AC voltage supplied from the AC power source into a DC voltage and supplies it to each driver circuit 74A to 74E. In this embodiment, each driver circuit 74A to 74E generates an AC drive signal DS for driving the motor from the DC voltage.

[0039] Driver circuits 74A to 74E are connected to motors 30, 31, 130, 242, and 245 of the transport robot 100, respectively. Specifically, the H1 axis driver circuit 74A is connected to the upper motor 242 by wiring that outputs a drive signal DS and wiring through which an encoder signal ES from the encoder circuit of the motor flows. The H1 axis driver circuit 74A controls the rotation of the output shaft of the upper motor 242 by outputting a drive signal DS corresponding to the control signal from the main controller 71 and the encoder signal ES to the upper motor 242.

[0040] The H2-axis driver circuit 74B is connected to the lower motor 245 by wiring that outputs a drive signal DS and wiring through which the encoder signal ES from the encoder circuit flows. The R-axis driver circuit 74C is connected to the R-axis motor 31 by wiring that outputs a drive signal DS and wiring through which the encoder signal ES flows. The T-axis driver circuit 74D is connected to the T-axis motor 30 by wiring that outputs a drive signal DS and wiring through which the encoder signal ES flows. The Z-axis driver circuit 74E is connected to the Z-axis motor 130 by wiring that outputs a drive signal DS, wiring through which the encoder signal ES flows and wiring through which the brake signal BS flows.

[0041] The transport robot 100 is equipped with pneumatic equipment 75. When each hand section 231, 232 holds a wafer using a vacuum suction method, the pneumatic equipment 75 controls the air pressure of each hand section 231, 232 using compressed air or vacuum supplied from an external source. The pneumatic equipment 75 is connected to the robot-side I / O 75 and receives control signal input via this robot-side I / O 75. The main controller 71 is connected to the robot-side I / O 75 of the transport robot 100 via the I / O circuit 77. When each hand section 231, 232 holds a wafer using a mechanical chuck method, the pneumatic equipment 75 controls the air pressure for driving the mechanical chuck.

[0042] Next, the operating range of the transport robot 100 will be explained. Figures 5 and 6 illustrate the transport robot 100 taking a wafer W from a wafer storage container 90 installed in the load port 80 and transporting it to the wafer transport chamber 95. Figure 5 shows the case where wafer W1, which is at the lowest position in the height direction D1, is taken out of the wafer storage container 90. Figure 6 shows the case where wafer W2, which is at the highest position in the height direction D1, is taken out of the wafer storage container 90. In Figures 5 and 6, for the sake of simplicity, only the upper hand portion 231 of the transport robot 100 is shown, and the lower hand portion 232 is omitted from the illustration.

[0043] As shown in Figures 5 and 6, a wafer storage container 90 is located in the load port 80. Wafers W are placed in the wafer storage container 90 at predetermined intervals in the height direction D1. In Figures 5 and 6, the illustration of the wafers W stored in the wafer storage container 90 is partially omitted. The load port 80 includes a table 81 for positioning and fixing the wafer storage container 90, and a port 82 that is in close contact with the loading / unloading entrance of the wafer storage container 90. On the opposite side of the loading / unloading entrance of the load port 80, separated by a door (not shown), is a wafer transport chamber 95. Behind the wafer transport chamber 95 is a device for performing predetermined processing on the wafers W removed from the wafer storage container 90. A transport robot 100 is installed inside the wafer transport chamber 95. Furthermore, the inside of the wafer transport chamber 95 may be replaced with an inert gas such as nitrogen or argon, or dry air, to prevent contamination of the wafers. In this case, it is preferable that the pressure inside the wafer transport chamber 95 be positive pressure compared to atmospheric pressure.

[0044] As shown in Figure 5, when the transport robot 100 retrieves a wafer W1 placed at the lowest position in the wafer storage container 90, it controls the position of the lifting base 12 in the height direction D1 to bring the upper hand portion 231 of the arm unit 20 to position P1. Then, it rotates the first arm 21 and the second arm 22 of the arm unit 20 to place and hold the wafer W1 on the upper hand portion 231 of the hand arm 23. In the examples shown in Figures 5 and 6, "position P1" is the home position of the transport robot 100, or in other words, the lowest position in the height direction of the upper hand portion 231.

[0045] On the other hand, as shown in Figure 6, when the transport robot 100 retrieves a wafer W2 placed at the highest position in the wafer storage container 90, it controls the position of the lifting base 12 in the height direction D1 to set the upper hand portion 231 of the arm unit 20 to position P2. Then, it rotates the first arm 21 and the second arm 22 of the arm unit 20 to place and hold the wafer W2 on the upper hand portion 231 of the hand arm 23. In the examples shown in Figures 5 and 6, "position P2" is the highest position in the height direction of the upper hand portion 231.

[0046] In the transport robot 100 with the above configuration, the lifting stroke ΔP, which is the operating range of the arm unit 20 in the height direction D1, can be controlled between P1 and P2. Here, position P1, which is the lower limit of the lifting stroke ΔP of the upper hand portion 231, is the lowest position of the upper hand portion 231 in the height direction D1, and the larger the dimension of the arm unit 20 in the height direction D1, the larger the value.

[0047] In this embodiment, the R-axis motor 31, which rotates the second arm 22 relative to the first arm 21 in the rotational direction of the R axis, is mounted so as to protrude below the arm axis holding portion 212 of the first arm 21. For example, when transporting heavy wafers or when increasing the wafer transport speed, the size of the R-axis motor 31 increases according to the performance such as the required rated torque. In the transport robot 100, even when the size of the R-axis motor 31 increases, the dimension H1 in the height direction D1 of the first arm 21 can be reduced compared to when the R-axis motor 31 is housed in the joint connecting the first arm 21 and the second arm 22. As a result, even when the position of the upper hand portion 231 in the height direction D1 is lowered to a desired position, clearance can be secured from the lower surface of the first arm 21 to the upper end of the fixed base 11. As a result, when the arm unit 20 is in its lowest position in the height direction D1, the position of the upper hand portion 231 can be set to a desired low position, and consequently, the lifting stroke ΔP of the hand portion 231 can be extended to a desired value.

[0048] The embodiment described above can achieve the following effects. In the arm unit 20, the R-axis motor 31, which rotates the second arm 22 in the rotational direction of the R axis, is fixed to the lower side of the second joint of the first arm 21, with its output shaft 311 facing upward. The R-axis motor 31 rotates the second arm 22 horizontally relative to the first arm 21 by passing its output shaft 311 through the first arm 21 from below, and by fixing the output shaft 311 to the second arm 22 by the shaft fixing part 50. As a result, even if the size (physique) of the R-axis motor 31 is increased according to the required motor performance, the increase in the height dimension H1 of the first arm 21 can be suppressed, and consequently, the limitations on the operating range of the arm unit 20 can be reduced.

[0049] The base section 10 includes a fixed base 11 and a lifting base 12 connected to the first arm 21 and capable of moving up and down in the height direction D1 from the fixed base 11. This allows the lifting stroke, which is the range of movement in the height direction D1, to be expanded to a desired value.

[0050] In the extension direction D2, if L is the distance from the output shaft 301 of the T-axis motor 30 to the output shaft 311 of the R-axis motor 31, the fixed base 11 is located horizontally inside the operating range of radius L, with reference to the output shaft 301 of the T-axis motor 30. When the first arm 21 is at its lowest position in the height direction D1 by the lifting base 12, the R-axis motor 31 does not interfere with the upper end of the fixed base 11. This allows for increased lifting stroke of each hand section 231, 232 while maintaining clearance between the lower surface of the first arm 21 and the upper end of the fixed base 11.

[0051] The second arm 22 has an arm shaft portion 221 that is held within the arm shaft holding portion 212 of the first arm 21 by an arm bearing 34 so as to be rotatable in the rotational direction of the R axis. The R axis motor 31 is detachably fixed to the lower surface of the arm shaft holding portion 212 of the first arm 21 by bolts. This allows the R axis motor 31 to be removed from the arm unit 20 without disconnecting the connection between the first arm 21 and the second arm 22. As a result, the maintainability of the R axis motor 31 can be improved.

[0052] Since the R-axis motor 31 is mounted on the outside of the first arm 21, even if a larger R-axis motor 31 is mounted on the first arm 21 to increase the rated torque, the dimensions of the first arm 21 in the height direction D1 do not increase. As a result, the transport robot 100 can increase the torque of the R-axis motor 31 while ensuring the lifting stroke of each hand section 231, 232, and can transport larger wafers.

[0053] (Other embodiments) The technologies disclosed herein are not limited to the embodiments described above and can be modified in various forms without departing from their essence, for example, the following modifications are possible. In the first embodiment described above, the arm unit 20 was a three-joint unit that rotated each arm 21, 22, and 23 relatively in the rotational direction of the T-axis, the R-axis, and the H-axis. Alternatively, the arm unit 20 may have four or more arms and be a unit with three or more joints. In this case as well, the R-axis motor 31 can be fixed to the lower surface of the first arm 21 connected to the base portion 10.

[0054] In the first embodiment described above, the hand arm 23 had an upper hand portion 231 and a lower hand portion 232. Alternatively, the hand arm 23 may have only the upper hand portion 231.

[0055] In the first embodiment described above, the base portion 10 had a lifting base 12 and a lifting drive unit 13, and the position of the arm unit 20 in the height direction D1 could be controlled within the lifting stroke. Alternatively, the base portion 10 does not have to have a lifting base 12 and a lifting drive unit 13. In this case, the T-axis motor 30 of the arm unit 20 only needs to be fixed to the fixed base 11. [Explanation of Symbols]

[0056] 10 Base section 11 Fixed base 12 Lifting base 20 Arm Units 21 First Arm 22. Second Arm 23 Hand Arm 30 T-axis motor 31 R-axis motor 50 Axis fixing part 70 Control device 100 Transport robots 231 Upper hand section 232 Lower hand section

Claims

1. A multi-jointed arm unit that changes the position of the hand part for transporting the workpiece, The base part, Equipped with, The aforementioned arm unit is A first arm is supported by a first joint located at one end, so as to be able to rotate horizontally relative to the base portion, A second arm is located above the first arm and supported by a second joint located on the other end of the first arm, so as to be able to rotate horizontally relative to the first arm, A rotary motor rotates the second arm at the second joint, It has, The aforementioned rotating motor is With the output shaft facing upward, it is fixed protruding from the lower side of the second joint of the first arm, The output shaft is passed through the first arm from below, and the output shaft is fixed to the second arm. In accordance with the rotation of the output shaft, the second arm is rotated horizontally relative to the first arm by the second joint. The second arm includes an arm shaft portion extending downward from one end of the second arm, The first arm includes a shaft holding portion located on the other end side of the first arm and having a recess into which the arm shaft portion is inserted. The aforementioned arm unit is Displaced between the first arm and the second arm, the arm bearing has an arm bearing within the shaft holding portion that holds the arm shaft portion so as to be rotatable in the horizontal direction, The arm shaft portion, the shaft holding portion, and the arm bearing constitute the second joint. The aforementioned rotating motor is detachably fixed to the lower side of the shaft holding portion of the first arm, in a transport robot.

2. The base portion is Fixed base and The transport robot according to claim 1, further comprising a lifting base connected to the first arm at the first joint and capable of moving up and down in the height direction from the fixed base.

3. When the distance from the pivot center of the first joint to the pivot center of the second joint in the first arm is L, the base portion is located inward in the horizontal direction, within a radius L range with respect to the pivot center of the first joint. The transport robot according to claim 2, wherein when the hand portion is at its lowest position in the height direction due to the lifting base, the rotating motor does not interfere with the upper end of the fixed base portion.

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