Horizontal articulated robot

Abstract

The present invention provides a horizontal articulated robot that can transport workpieces in the same direction simultaneously, has a low path line when the height of the lifting device is lowered, and is compact despite being capable of lifting. [Solution] In the horizontal articulated robot 1, the right robot section 2 comprises a right first arm 21, a right first joint 22, a right second arm 23, and a right end effector 24. The left robot section 3 comprises a left first arm 31, a left first joint 32, a left second arm 33, and a left end effector 34. The chuck sections 242 and 243 of the right end effector 24 are positioned below the right second arm 23 and above the right first arm 21, and the chuck sections 342 and 343 of the left end effector 34 are positioned below the left second arm 33 and above the left first arm 31, with either the chuck sections 242 and 243 or the chuck sections 342 and 343 positioned above the other.

Description

Technical Field

[0001] The present invention relates to a horizontal articulated robot.

Background Art

[0002] Some horizontal articulated robots are equipped with a lifting device to supply a workpiece into a plurality of loading and unloading ports inside the device with different path line heights or to discharge the workpiece from inside the same loading and unloading port.

[0003] For example, Patent Document 1 discloses a horizontal articulated robot in which a robot unit having a right first arm, a right second arm provided below the right first arm, a right end effector provided below the right second arm, a left first arm, a left second arm provided below the left first arm, and a left end effector provided below the left second arm moves up and down in front of a columnar lifting device.

[0004] Further, Patent Document 2 discloses a horizontal articulated robot including a first arm extending in the left-right direction, a right second arm provided above the right end portion of the first arm, a right end effector provided above the right second arm, a left second arm provided above the left end portion of the first arm, and a left end effector provided above the left second arm, and the left end effector is located above the right end effector.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] The horizontal articulated robot described in Patent Document 1 has a right first arm, a right second arm, and a right end effector arranged downwards in that order. Similarly, the left first arm, the left second arm, and the left end effector are also arranged downwards in that order. As a result, when the lifting device lowers the robot section to its lowest position, its path line can be made lower.

[0007] However, by suspending the robot section with an arm suspension unit, and further positioning that arm suspension unit in front of the lifting unit for lifting and lowering, the horizontal articulated robot becomes larger in both the vertical and horizontal directions.

[0008] On the other hand, the horizontal articulated robot described in Patent Document 2 is large in the left-right direction because a right second arm and a left second arm are positioned at each end of the first arm. Furthermore, in the horizontal articulated robot described in Patent Document 2, the left second arm is positioned on the left end portion of the left first arm, and the left end effector is positioned on top of that left second arm. As a result, the pass line is located above the distance including the vertical thickness of the left second arm, making it impossible to lower the pass line.

[0009] Furthermore, in the horizontal articulated robot described in Patent Document 2, as a result of having a right second arm and a left second arm positioned at each end of the first arm, it is not possible to transport multiple workpieces simultaneously in the same direction, for example, simultaneously in the forward or backward direction. Or, it is not possible to transport multiple workpieces simultaneously in both the forward and backward directions.

[0010] The present invention was made to solve the above problems, and aims to provide a horizontal articulated robot that can transport workpieces in the same direction simultaneously, has a low path line when the height of the lifting device is lowered, and is compact despite being able to move up and down. [Means for solving the problem]

[0011] To achieve the above objective, the horizontal articulated robot according to the present invention is A horizontal articulated robot comprising a base that can be raised and lowered by a lifting device, and a right robot section and a left robot section mounted on the base and arranged in the left-right direction, The base has a right first rotation axis and a left first rotation axis arranged in the left-right direction and extending in the up-down direction, The aforementioned right robot section is The base is positioned on the base and connected to the right first pivot shaft, and the tip of the right first arm pivots as the right first pivot shaft rotates, A columnar right joint portion extending upward from the tip of the right first arm, The base of the right second arm is positioned on the right joint and connected to the right second pivot axis of the right joint, and the tip of the right second arm rotates as the right second pivot axis rotates, A right chuck portion for chucking a workpiece, and a right end effector provided on the lower side of the tip of the right second arm, Equipped with, The left robot section is, The base is positioned on the base and connected to the left first pivot axis, and the tip of the left first arm pivots as the left first pivot axis rotates, A columnar left joint portion extending upward from the tip of the left first arm, The base of the left second arm is positioned on the left joint and connected to the left second pivot axis of the left joint, and the tip of the left second arm rotates as the left second pivot axis rotates, It has a left chuck portion for chucking a workpiece, and a left end effector provided on the lower side of the tip of the left second arm, Equipped with, The right chuck portion is positioned below the right second arm and above the right first arm. The left chuck portion is positioned below the left second arm and above the left first arm. Either the right chuck portion or the left chuck portion is positioned above the other of the right chuck portion or the left chuck portion. It is characterized by the following:

[0012] The right second arm and the left second arm are positioned at the same height in the vertical direction. The right end effector has a right connecting portion that connects to the tip of the right second arm and positions the right chuck portion below the right second arm. The left end effector has a left connecting portion that connects to the tip of the left second arm and positions the right chuck portion below the left second arm. Either the right chuck portion or the left chuck portion may be positioned above the other of the right chuck portion or the left chuck portion if the vertical thickness of either the right connecting portion or the left connecting portion is smaller than the vertical thickness of the other of the right connecting portion or the left connecting portion.

[0013] The lifting device has a telescopic mechanism that can extend and retract vertically. The aforementioned base is, It comprises a right actuator that drives the right first arm and the right second arm, and a left actuator that drives the left first arm and the left second arm, It may be positioned on the telecosmic mechanism and be rotatable on the telecosmic mechanism.

[0014] A right stopper is provided which, by projecting from either the base or the base of the right first arm toward the other part of the base or the base of the right first arm, and by contacting a right projection provided on the other part, restricts the rotation of the right first arm by the right first pivot axis. A left stopper is provided which, by projecting from either the base or the base of the left first arm toward the other part of the base or the base of the left first arm, and by contacting a left projection provided on the other part, restricts the rotation of the left first arm by the left first pivot axis. Furthermore, When the tip of the right first arm rotates due to the rotation of the right first rotation axis, the right stopper abuts against the right protrusion and restricts the rotation of the right first arm about the right first rotation axis before the right joint portion at the tip of the right first arm interferes with the work chucked by the left chuck portion or the left end effector. When the tip of the left first arm rotates due to the rotation of the left first rotation axis, the left stopper may abut against the left protrusion and restrict the rotation of the left first arm about the left first rotation axis before the left joint portion at the tip of the left first arm interferes with a work different from the work chucked by the right chuck portion or the right end effector.

Advantages of the Invention

[0015] According to the configuration of the present invention, the right first arm and the left first arm are arranged on the base. Therefore, regardless of the vertical position of the base, even if the right first arm and the left first arm rotate, they do not interfere with the base. As a result, in order to prevent interference with the base, it is not necessary to displace the base in the front-rear direction or the left-right direction from the lifting device. As a result, the horizontal articulated robot according to the present invention is small in size despite being able to be lifted.

[0016] Further, the right chuck portion is disposed below the right second arm and above the right first arm, and the left chuck portion is disposed below the left second arm and above the left first arm. As a result, the right chuck portion is disposed between the right second arm and the right first arm, and the left chuck portion is disposed between the left second arm and the left first arm. Thereby, the horizontal articulated robot according to the present invention has a low pass line despite the base being able to be lifted and the horizontal articulated robot itself being small in size.

[0017] Furthermore, either the right or left chuck is positioned above the other. Therefore, even when the right and left end effectors move simultaneously in the same direction, for example, simultaneously in the forward and backward directions, the right and left chucks do not interfere with each other. As a result, the horizontal articulated robot according to the present invention can transport workpieces simultaneously in the same direction. [Brief explanation of the drawing]

[0018] [Figure 1] (A) A right side view of a horizontal articulated robot according to an embodiment of the present invention. (B) A right side view of the horizontal articulated robot when the base of the lifting device provided by the horizontal articulated robot is raised to its highest position. (C) A front view of the horizontal articulated robot. (D) A top view of the horizontal articulated robot. [Figure 2] (A) This figure shows the internal mechanism of the lifting device of the horizontal articulated robot according to the embodiment. (B) This figure shows the internal mechanism of the lifting device when the base is lowered to its lowest position. [Figure 3] (A) An enlarged front view of the right and left robot sections of the horizontal articulated robot according to the embodiment. (B) An enlarged front view of the horizontal articulated robot according to related technology. [Figure 4] (A) A top view of the horizontal articulated robot according to the embodiment when the left end effector of the left robot section is advanced. (B) A top view of the same horizontal articulated robot when the right end effector of the right robot section is advanced. (C) A top view of the same horizontal articulated robot when both the right end effector of the right robot section and the left end effector of the left robot section are advanced. (D) A top view of the same horizontal articulated robot in a standby state. [Figure 5](A) A top view showing an example of the left robot section of the horizontal articulated robot according to the embodiment when the left end effector is moved forward. (B) A top view showing another example of the left robot section of the horizontal articulated robot when the left end effector is moved forward. (C) A top view showing an example of the left robot section of the horizontal articulated robot when the left end effector is moved backward. (D) A top view showing another example of the left robot section of the horizontal articulated robot when the left end effector is moved backward. [Figure 6] (A) An enlarged right side view of a horizontal articulated robot according to an embodiment. (B) A top view showing an example of a stopper mechanism when the right robot section of the horizontal articulated robot moves the right end effector forward. (C) A top view showing an example of a stopper mechanism when the right robot section moves the right end effector backward. [Modes for carrying out the invention]

[0019] Hereinafter, a horizontal articulated robot according to an embodiment of the present invention will be described in detail with reference to the drawings. In the drawings below, the same or equivalent parts will be denoted by the same reference numerals. In the Cartesian coordinate system XYZ shown in the drawings, when viewing a horizontal articulated robot with the arm extended and the end effector advancing in the forward direction, the front-to-back direction is the Y axis, the left-to-right direction is the X axis, and the up-to-down direction is the Z axis. The arrow direction of each XYZ axis is the + side, and the opposite is the - side. Hereafter, this coordinate system will be referred to as appropriate in the explanation.

[0020] The horizontal articulated robot according to this embodiment is a so-called twin-arm robot. This horizontal articulated robot is equipped with a base that moves up and down by a lifting device in order to supply workpieces into or discharge openings of a device with different pass line heights. The right and left robot sections of the twin arms are mounted on this base. Furthermore, in order to make the pass line as low as possible when the base is lowered, end effectors are positioned under the tip arms of both the right and left robot sections.

[0021] The following description of a horizontal articulated robot according to an embodiment will be based on the example of a case where the workpiece is a rectangular glass plate and the lifting device is a device that moves up and down by a telecosmic mechanism. First, the lifting device of the horizontal articulated robot will be described with reference to Figures 1 and 2.

[0022] Figures 1(A), (C), and (D) are the right side view, front view, and top view of a horizontal articulated robot 1 according to an embodiment of the present invention. Figure 1(B) is a right side view of the horizontal articulated robot 1 when the base 5 of the lifting device 4 equipped with the horizontal articulated robot 1 is raised to its highest position. Figure 2(A) is a diagram showing the internal mechanism of the lifting device 4. Figure 2(B) is a diagram showing the internal mechanism of the lifting device 4 when the base 5 is lowered to its lowest position. Note that Figures 1(A), (C), and (D) show the horizontal articulated robot 1 when the base 5 of the lifting device 4 is lowered to its lowest position. Also, in Figures 2(A) and (B), conceptual diagrams are shown with each component unfolded horizontally for ease of understanding.

[0023] (Lifting device) As shown in Figures 1(A) and 1(B), the horizontal articulated robot 1 is equipped with a lifting device 4 that raises and lowers the right robot section 2 and the left robot section 3.

[0024] The lifting device 4 has a telecosmic mechanism, which raises and lowers the base 5. In detail, as shown in Figure 1(B), the lifting device 4 has four cylinders 41, 42, 43, and 44, each with a different diameter and their shafts oriented vertically. In the lifting device 4, each of the smaller diameter cylinders 41, 42, and 43 is inserted into each of the larger diameter cylinders 42, 43, and 44. Furthermore, each of the cylinders 41, 42, and 43 is slidable relative to each of the cylinders 42, 43, and 44. As a result, the lifting device 4 is extendable and retractable in the vertical direction. The lifting device 4 has such a telecosmic mechanism.

[0025] To describe the telescopic mechanism in more detail, the cylinder 44 houses a motor 441 as shown in Figures 2(A) and 2(B), a screw shaft 442 extending vertically, a nut 443 attached to the screw shaft 442 and forming a ball screw together with the screw shaft 442, and a ball spline 444 positioned parallel to the screw shaft 442 and guiding the nut 443 in its extending direction. A belt 445 is wrapped around the output shaft of the motor 441 and the lower end of the screw shaft 442. As a result, when the motor 441 rotates, the screw shaft 442 rotates, and the nut 443 moves up and down along the ball spline 444 according to the amount and direction of rotation. The cylinder 43 shown in Figure 1(B) is connected to the nut 443, and as a result, the cylinder 43 moves up and down.

[0026] Furthermore, the cylinder 43 houses a vertically extending screw shaft 432, a nut 433 attached to the screw shaft 432 and forming a ball screw together with the screw shaft 432, and a ball spline 434 arranged parallel to the screw shaft 432 and guiding the nut 433 in its extending direction, as shown in Figures 2(A) and 2(B).

[0027] Meanwhile, the nut 443 inside the cylinder 44 is equipped with a pulley (not shown) that rotates in conjunction with the rotation of the screw shaft 442. The ball spline 444 inside the cylinder 44 is a rotary ball spline, and as a result, a nut (not shown) is rotatably mounted around the spline axis. In the cylinder 44, a belt 446 is wrapped between the pulley (not shown) on the nut 443 and the nut (not shown) on the ball spline 444. Furthermore, a belt 435 is wrapped between the nut (not shown) on the ball spline 444 and the lower end of the screw shaft 432 inside the cylinder 43. As a result, when the screw shaft 442 inside the cylinder 44 is rotated by the motor 441, the screw shaft 432 inside the cylinder 43 rotates in conjunction with it, and the nut 433 moves up and down along the ball spline 434 inside the cylinder 43 according to the amount and direction of rotation. The cylinder 42 shown in Figure 1(B) is connected to the nut 433, and as a result, the cylinder 42 moves up and down.

[0028] Furthermore, the cylinder 42 houses a vertically extending screw shaft 422, as shown in Figures 2(A) and 2(B), and a nut 423 attached to the screw shaft 422, which together with the screw shaft 422 constitute a ball screw.

[0029] On the other hand, the nut 433 inside the cylinder 43 is equipped with a pulley (not shown) that rotates in conjunction with the rotation of the screw shaft 432, similar to the nut 443 inside the cylinder 44. The ball spline 434 inside the cylinder 43 is a rotary ball spline, similar to the ball spline 444 inside the cylinder 44, and as a result, a nut (not shown) is rotatably mounted around the spline axis. In the cylinder 43, a belt 436 is wrapped between the pulley (not shown) on the nut 433 and the nut (not shown) on the ball spline 434. Furthermore, a belt 425 is wrapped between the nut (not shown) on the ball spline 434 and the lower end of the screw shaft 422 inside the cylinder 42. As a result, when the screw shaft 432 inside the cylinder 43 rotates in conjunction with the rotation of the screw shaft 442 inside the cylinder 44 by the motor 441, the screw shaft 422 inside the cylinder 42 rotates in conjunction with this, and the nut 423 moves up and down according to the amount and direction of rotation. The cylinder 41 shown in Figures 1(A) and 1(B) is connected to the nut 423, and as a result, the cylinder 41 moves up and down.

[0030] A base 5 is provided at the upper end of the telescopic lifting device 4, specifically at the upper end of the cylinder 41 of the lifting device 4. The right robot section 2 and the left robot section 3, which are the twin arms of the horizontal articulated robot 1, are mounted on the base 5. Furthermore, although not shown in the figures, the base 5 is rotatable relative to the lifting device 4 by an actuator provided inside the cylinder 41 of the lifting device 4. As a result, the right robot section 2 and the left robot section 3 can rotate along the horizontal plane, for example, to face forward or backward, or to the right or left.

[0031] In contrast, in the horizontal articulated robot described in Patent Document 1, the robot section is positioned in front of the lifting device, resulting in the horizontal articulated robot itself being larger. Furthermore, the robot section cannot rotate in the left-right direction because it interferes with the lifting device.

[0032] As is clear from this, the horizontal articulated robot 1 according to this embodiment is compact because the right robot section 2 and the left robot section 3 are mounted on the base 5, and are not enlarged in the front-to-back or left-to-right directions. Furthermore, the horizontal articulated robot 1 is compact despite the fact that the right robot section 2 and the left robot section 3 can rotate along the horizontal plane.

[0033] Furthermore, the horizontal articulated robot 1's base 5 is raised and lowered by the lifting device 4. Therefore, the horizontal articulated robot 1 can supply workpieces to multiple discharge / exit ports of a device with different pass line heights, or discharge workpieces from within the same ports. For example, it can supply workpieces to a device such as a firing furnace with vertically arranged discharge / exit ports, or discharge workpieces from such a device.

[0034] However, in the horizontal articulated robot 1, simply having the right robot section 2 and the left robot section 3 on the base 5 is not enough to lower the path line sufficiently. Therefore, in the horizontal articulated robot 1, as shown in Figures 1(C) and 1(D), a right end effector 24 is provided below the tip of the right second arm 23 of the right robot section 2 in order to lower the path line. Similarly, a left end effector 34 is provided below the tip of the left second arm 33 of the left robot section 3. In addition, the right end effector 24 and the left end effector 34 are arranged vertically to enable the right robot section 2 and the left robot section 3 to transport the workpiece in the same direction.

[0035] Next, the right robot section 2 and the left robot section 3 of the horizontal articulated robot 1 will be described in detail with reference to Figures 3 and 4.

[0036] Figure 3(A) is an enlarged front view of the right robot section 2 and left robot section 3 of the horizontal articulated robot 1. Figure 3(B) is an enlarged front view of a horizontal articulated robot 100 relating to related technology. Figure 4(A) is a top view of the horizontal articulated robot 1 when the left end effector 34 of the left robot section 3 is advanced. Figure 4(B) is a top view of the horizontal articulated robot 1 when the right end effector 24 of the right robot section 2 is advanced. Figure 4(C) is a top view of the horizontal articulated robot 1 when both the right end effector 24 of the right robot section 2 and the left end effector 34 of the left robot section 3 are advanced. Figure 4(D) is a top view of the horizontal articulated robot 1 in standby mode. Note that in Figures (A) and 3(B), the internal right actuator 51, left actuator 52, etc. are also shown for ease of understanding. Note that in Figure 4, the +Y direction is the front side. Therefore, the left side of the drawing, i.e., the +X side, is the right side of the horizontal articulated robot 1.

[0037] (Right robot section) As shown in Figure 3(A), the right robot unit 2 includes a right first arm 21, a right second arm 23, and a right end effector 24.

[0038] The base of the right first arm 21 is positioned on a base 5. Inside the base 5 are a right actuator 51 and a left actuator 52, which are arranged in the left-right direction. Each of the right actuator 51 and the left actuator 52 includes a right first pivot axis and a left first pivot axis, respectively, which extend in the vertical direction (not shown), and rotates these right first pivot axes and left first pivot axes, respectively. The base of the right first arm 21 is connected to the right first pivot axis of the right actuator 51. As a result, when the right actuator 51 rotates the right first pivot axis, the tip of the right first arm 21 is rotated by that right first pivot axis. Meanwhile, the tip of the right first arm 21 is provided with a right first joint 22.

[0039] The right first joint 22 is formed in the shape of a column of a certain length, in other words, cylindrical. The right first joint 22 has its cylindrical axis oriented vertically and extends upward from the upper surface of the right first arm 21. The base of the right second arm 23 is connected to the upper end of the right first joint 22. This positions the right second arm 23 above the right first arm 21, preventing interference between the right second arm 23 and the upper end of the lifting device 4, i.e., the base 5, when the right second arm 23 is in operation.

[0040] Furthermore, the length L1 of the cylinder of the right first joint 22 is greater than the thickness T1 of the right end effector 24. As will be described later, the right end effector 24 is positioned below the right second arm 23. The right first joint 22 has such a length L1 that it secures space to position the right end effector 24 below the right second arm 23. As a result, the right first joint 22 makes it possible to position the right end effector 24 below the right second arm 23, thereby lowering the path line when transporting the workpiece.

[0041] Furthermore, although not shown in the figure, the right first joint 22 is provided with a right second pivot shaft. The right second pivot shaft is connected to the right first pivot shaft of the right actuator 51 by a transmission device having a pulley including gears and a belt wrapped in a cross-belt system. As a result, when the right first pivot shaft of the right actuator 51 rotates, the right second pivot shaft of the right first joint 22 rotates in accordance with that rotation. It also rotates in the opposite direction to the rotation of the right first pivot shaft of the right actuator 51. Moreover, it rotates by twice the angle of rotation of the right first pivot shaft of the right actuator 51. The base of the right second arm 23 shown in Figure 3(A) is connected to the right second pivot shaft of the right first joint 22. As a result, when the right actuator 51 rotates the right first pivot axis of the right first joint 22, the right second pivot axis rotates the tip of the right second arm 23 in the opposite direction to the rotation direction, that is, in the opposite direction to the rotation direction of the tip of the right first arm 21. In addition, the tip of the right second arm 23 rotates by twice the angle of rotation of the tip of the right first arm 21.

[0042] The right second arm 23 has approximately the same length as the right first arm 21. As described above, the right second arm 23 rotates its tip in the opposite direction to the tip of the right first arm 21 by twice the rotation angle of the tip of the right first arm 21, due to the rotation of the right second pivot axis of the right first joint 22. With this configuration, the right second arm 23 positions its tip directly in front of or behind the base of the right first arm 21, as shown in Figures 4(A)-4(D). The right end effector 24 is connected to the tip of the right second arm 23. As a result, the right second arm 23 positions the right end effector 24 directly in front of or behind the base of the right first arm 21.

[0043] Furthermore, the tip of the right second arm 23, although not shown, has a right second joint, and a right third pivot shaft is located at this right second joint. The right third pivot shaft is connected to the right second pivot shaft of the right first joint 22 by a transmission device comprising a pulley including gears and a belt wrapped in a cross-belt configuration. As a result, the right third pivot shaft rotates in accordance with the rotation of the right second pivot shaft of the right first joint 22. It also rotates in the opposite direction to the rotation of the right second pivot shaft of the right first joint 22. Moreover, it rotates by half the angle of rotation of the right second pivot shaft of the right first joint 22. Consequently, the right third pivot shaft rotates in conjunction with the rotation of the right first pivot shaft, which is rotated by the right actuator 51, by the same angle and in the same direction as that rotation. The right end effector 24, as described above, is connected to the right third pivot axis in a forward-facing position, as shown in Figures 4(A)-4(D). However, due to this rotation of the right third pivot axis, the right end effector 24 maintains its forward-facing position even though the right first pivot axis of the right actuator 51 and the right second pivot axis of the right first joint 22 are rotating.

[0044] On the other hand, as shown in Figure 4(B), the right end effector 24 has a connecting portion 241 that connects to the tip of the right second arm 23, and two rod-shaped chuck portions 242 and 243 that extend parallel to each other from the connecting portion 241.

[0045] The connecting portion 241 has a roughly rectangular shape with its longitudinal direction oriented left to right in a plan view. Chuck portions 242 and 243 are provided on the parts of the connecting portion 241 that have sides extending in the longitudinal direction of the roughly rectangular shape, extending straight forward. This allows the connecting portion 241 to separate the chuck portions 242 and 243 from each other in the left to right direction, enabling stable workpiece holding by the chuck portions 242 and 243.

[0046] Furthermore, as described above, the connecting portion 241 is connected to a right third pivot axis (not shown) located at the tip of the right second arm 23. As a result, as described above, the connecting portion 241 follows the rotation of the right first pivot axis of the right actuator 51 and the right second pivot axis of the right first joint portion 22. As a result of this following, the connecting portion 241 maintains a forward-facing position even though the right first pivot axis of the right actuator 51 and the right second pivot axis of the right first joint portion 22 are rotating. This allows the connecting portion 241 to maintain a state in which the chuck portions 242 and 243 extend forward. Consequently, the connecting portion 241 facilitates the holding and transport of workpieces by the chuck portions 242 and 243.

[0047] Furthermore, as shown in Figure 3(A), the connecting section 241 is positioned below the tip of the right second arm 23. The connecting section 241 has an inverted L-shape, extending straight down from the tip of the right second arm 23 in a front view, and then extending to the left and horizontally. Chuck sections 242 and 243 are provided on the portion extending to the left and horizontally. As a result, the connecting section 241 lowers the position of the chuck sections 242 and 243 and positions them in the center. Consequently, the connecting section 241 lowers the path line when transporting workpieces and brings the workpiece to be transported closer to the center, enabling the right robot section 2 and the left robot section 3 to transport workpieces in the same direction.

[0048] Each of the chuck portions 242 and 243 has the shape of a thin rod extending straight forward, as shown in Figures 4(A) to 4(D). It also has a workpiece suction mechanism (not shown). The chuck portions 242 and 243 are positioned apart from each other in the left-right direction. As a result, as shown in Figures 1(A) to 1(D), the chuck portions 242 and 243 support the workpiece W from below, suctioning and holding the workpiece W. In this specification, "chucking" means holding a workpiece.

[0049] (Left robot section) Returning to Figure 3(A), the left robot section 3 includes a left first arm 31, a left second arm 33, and a left end effector 34.

[0050] The left first arm 31 has a shape symmetrical to that of the right robot unit 2. The base of the left first arm 31 is positioned on the base 5, similar to the right first arm 21 of the right robot unit 2. The left first arm 31 is connected to the left first pivot axis (not shown) of the left actuator 52 described above. As a result, when the left actuator 52 rotates the left first pivot axis, the tip of the left first arm 31 is rotated by that left first pivot axis. Meanwhile, the tip of the left first arm 31 is provided with a left first joint 32.

[0051] The left first joint 32 has a shape that is symmetrical to the right first joint 22 of the right robot unit 2. As a result, the left first joint 32 extends upward from the upper surface of the left first arm 31, and the base of the left second arm 33 is connected to its upper end. In this way, the left first joint 32, like the right first joint 22 of the right robot unit 2, positions the left second arm 33 above the left first arm 31, preventing interference with the base 5 when the left second arm 33 moves. Furthermore, the left first joint 32 positions the left second arm 33 at the same height as the right second arm 23 of the right robot unit 2.

[0052] Furthermore, the length L2 of the left first joint 32 is the same as the length L1 of the right first joint 22 of the right robot unit 2, and is greater than the thickness T1 of the right end effector 24, as well as the thickness T2 of the left end effector 34. As will be described later, the left end effector 34 is positioned below the left second arm 33. By having such a length L2, the left first joint 32 secures space to position the left end effector 34 below the left second arm 33, similar to the right first joint 22 of the right robot unit 2. As a result, the left first joint 32 makes it possible to position the left end effector 34 below the left second arm 33, thereby lowering the path line when transporting the workpiece W.

[0053] Furthermore, the left first joint 32, although not shown, has a left second pivot axis, similar to the right first joint 22 of the right robot unit 2. The relationship between this left second pivot axis and the left first pivot axis of the left actuator 52 (not shown) is the same as the relationship between the right second pivot axis of the right robot unit 2 and the right first pivot axis of the right actuator 51 (not shown), except that it is symmetrical. For this reason, a detailed explanation of these components and related structures is omitted. The left second pivot axis of the left first joint 32 (not shown) causes the tip of the left second arm 33 to rotate in the opposite direction to the rotation of the left first pivot axis when the left actuator 52 rotates the left first pivot axis, that is, in the opposite direction to the rotation of the tip of the left first arm 31. It also causes the tip of the left second arm 33 to rotate by twice the angle of rotation of the tip of the left first arm 31.

[0054] The left second arm 33 has a shape symmetrical to the right second arm 23. As a result, the left second arm 33 has approximately the same length as the left first arm 31. In addition, similar to the rotation of the tip of the right second arm 23, the left second arm 33 rotates its tip in the opposite direction to the tip of the left first arm 31 by the rotation of the left second pivot axis of the left first joint 32, by an angle twice the rotation angle of the tip of the left first arm 31. With this configuration, the left second arm 33 positions its tip directly in front of or behind the base of the left first arm 31, as shown in Figures 4(A) to 4(D). As a result of the left end effector 34 being connected to the tip of the left second arm 33, the left second arm 33 positions the left end effector 34 directly in front of or behind the base of the left first arm 31.

[0055] Furthermore, the tip of the left second arm 33, similar to the tip of the right second arm 23 of the right robot unit 2, has a left second joint (not shown), and a left third pivot axis at that left second joint. The relationship between this left third pivot axis and the left second pivot axis of the left first joint 32 is the same as the relationship between the right third pivot axis of the right robot unit 2 and the right second pivot axis of the right first joint 22, except that it is symmetrical. Also, the relationship between this left third pivot axis and the left end effector 34 is the same as the relationship between the right third pivot axis of the right robot unit 2 and the right end effector 24, except that it is symmetrical. For this reason, a detailed explanation of these components and related structures is omitted. The left third pivot axis rotates in conjunction with the rotation of the left first pivot axis, which rotates the left actuator 52, by the same angle and in the same direction as that rotation. Furthermore, the left third pivot axis maintains the left end effector 34 facing forward, even though the left first pivot axis of the left actuator 52 and the left second pivot axis of the left first joint 32 are rotating.

[0056] As shown in Figure 4(A), the left end effector 34 has a connecting portion 341 that connects to the tip of the left second arm 33, and two rod-shaped chuck portions 342 and 343 that extend parallel to each other from the connecting portion 341. Of these components, the chuck portions 342 and 343 have the same shape and function as the chuck portions 242 and 243 of the right robot portion 2, so a detailed explanation will be omitted. The connecting portion 341 of the left end effector 34 will be described below.

[0057] The connecting portion 341 has an inverted L-shape in plan view. More specifically, the connecting portion 341 protrudes diagonally forward to the left from the tip of the left second arm 33, then bends to the right and extends straight. Chuck portions 342 and 343 are provided on the portion that extends straight to the right. As a result, the connecting portion 341, like the connecting portion 241, enables stable holding of the workpiece W by the chuck portions 342 and 343.

[0058] Furthermore, as described above, the connecting portion 341 is connected to the left third pivot axis (not shown) at the tip of the left second arm 33. As a result, the connecting portion 341, like the connecting portion 241 of the right robot unit 2, follows the rotation of the left first pivot axis of the left actuator 52 and the left second pivot axis of the left first joint portion 32. As a result of this following, the connecting portion 341 maintains a forward-facing position even though the left first pivot axis of the left actuator 52 and the left second pivot axis of the left first joint portion 32 are rotating. This allows the connecting portion 341, like the connecting portion 241 of the right robot unit 2, to maintain a forward-extending position for the chuck portions 342 and 343, facilitating the holding and transport of the workpiece W by the chuck portions 342 and 343.

[0059] Furthermore, as shown in Figure 3(A), the connecting portion 341 is positioned below the tip of the left second arm 33, similar to the connecting portion 241 of the right robot unit 2. Unlike the connecting portion 241 of the right robot unit 2, the connecting portion 341 has a roughly inverted U-shape when viewed from the front. In detail, when viewed from the front, the connecting portion 341 extends horizontally to the left from below the tip of the left second arm 33, then bends straight down and extends straight down, and then bends to the right and extends horizontally to the right. Chuck portions 342 and 343 are provided in the portion that extends horizontally to the right. This lowers the position of the chuck portions 342 and 343 in the connecting portion 341, and positions the chuck portions 342 and 343 in the center, similar to the case of the connecting portion 241 of the right robot unit 2. As a result, the connecting section 341 lowers the path line when transporting the workpiece W and brings the workpiece W to be transported closer to the center. Furthermore, the connecting section 341 enables the right robot section 2 and the left robot section 3 to transport the workpiece W in the same direction.

[0060] Furthermore, in the approximately inverted U-shape of the connecting section 341 as described above when viewed from the front, the height H1 of the internal space is greater than the thickness T3 of the inverted L-shaped horizontal section of the connecting section 241 of the right robot section 2. The connecting section 341 positions the horizontal section of the connecting section 241 of the right robot section 2 within this approximately inverted U-shaped internal space. This prevents interference between the connecting section 341 and the connecting section 241 of the right robot section 2. In addition, the chuck sections 342 and 343 on the connecting section 341 of the left robot section 3 are positioned below the chuck sections 242 and 243 on the connecting section 241 of the right robot section 2, lowering the path line when the left robot section 3 transports the workpiece W. Furthermore, the chuck sections 242 and 243 and the chuck sections 342 and 343 are arranged to overlap vertically, enabling the right robot section 2 and the left robot section 3 to transport the workpiece W in the same direction.

[0061] To illustrate how the path line is lowered by the connecting section 341, related technology is shown in Figure 3(B). The horizontal articulated robot 100 relating to the related technology shown in Figure 3(B) includes, on a base 115, a first arm 101 that can be rotated by an actuator 150, a right second arm 102 that can be rotated by an actuator 151 provided at the right end of the first arm 101, and a right end effector 103 positioned below the right second arm 102. Furthermore, the horizontal articulated robot 100 includes a left second arm 104 that can be rotated by an actuator 152 provided at the left end of the first arm 101, and a left end effector 105 positioned above the left second arm 104. In the horizontal articulated robot 100, as a result of the left second arm 104 being positioned below the left end effector 105, the path line when the workpiece W is transported by the left end effector 105 is not lowered. Furthermore, because actuators 151 and 152 are built into each end of the first arm 101, the horizontal articulated robot 100 itself has become larger.

[0062] In contrast, in the horizontal articulated robot 1 according to this embodiment, as shown in Figure 3(A), the right second arm 23 of the right robot section 2 and the left second arm 33 of the left robot section 3 are positioned at the same height, with the right end effector 24 positioned below the right second arm 23. Also, the left end effector 34 is positioned below the left second arm 33. As a result, neither the right second arm 23 nor the left second arm 33 is positioned below the right end effector 24 or the left end effector 34. This results in a lower path line when transporting the workpiece W compared to the horizontal articulated robot 100 according to related technology.

[0063] Furthermore, in the related horizontal articulated robot 100, as shown in Figure 3(B), the right second arm 102 and the left second arm 104 are connected to each end of the first arm 101, respectively, so the workpiece W cannot be transported simultaneously in the same direction.

[0064] In contrast, the horizontal articulated robot 1 according to this embodiment, as shown in Figure 3(A), has a right robot section 2 and a left robot section 3 that operate independently, and the connecting section 241 of the right end effector 24 and the connecting section 341 of the left end effector 34 are formed in such a shape that they do not interfere with each other when the right end effector 24 and the left end effector 34 are moved in the front-rear direction. That is, the connecting section 341 has a shape that is roughly like an inverted U when viewed from the front, and the connecting section 241 is arranged in the internal space of this inverted U shape. Because the connecting sections 241 and 341 of the horizontal articulated robot 1 have this shape and arrangement, the workpiece W can be transported simultaneously in the same direction, that is, simultaneously in the same front-rear direction.

[0065] (Stopper mechanism) Thus, in the horizontal articulated robot 1, the connecting portion 241 of the right end effector 24 and the connecting portion 341 of the left end effector 34 are shaped so that they do not interfere with each other when the right end effector 24 and the left end effector 34 are moved in the front-back direction. However, the right end effector 24 is positioned at the same height as the left first joint portion 32 of the left robot section 3. That is, it is positioned at a height that overlaps with the left first joint portion 32 of the left robot section 3 in the left-right direction. As a result, the right end effector 24 may interfere with the left first joint portion 32 of the left robot section 3.

[0066] Similarly, the left end effector 34 is positioned at the same height as the right first joint 22 of the right robot unit 2. That is, it is positioned at a height that overlaps with the right first joint 22 in the left-right direction. As a result, the left end effector 34 may interfere with the right first joint 22 of the right robot unit 2.

[0067] Examples of interference between the left first joint 32 of the left robot unit 3 and the right end effector 24 of the right robot unit 2 are shown in Figures 5(A) to 5(D), and the following explanation will be given with reference to Figures 5(A) to 5(D).

[0068] Figures 5(A) and 5(B) are top views showing one example and another example of the left robot section 3 of the horizontal articulated robot 1 moving the left end effector 34 forward. Figures 5(C) and 5(D) are top views showing one example and another example of the left robot section 3 moving the left end effector 34 backward. In Figure 5, as in Figure 4, the +Y side is the front side. Therefore, the left side in the drawing, i.e., the +X side, is the right side of the horizontal articulated robot 1.

[0069] As shown in Figure 5(A), if the left robot unit 3 advances the left end effector 34 too far forward, the left first arm 31 will be tilted only slightly to the left of the horizontal articulated robot 1 from the front, that is, only slightly tilted from the +Y direction to the -X side. As a result, the left first joint 32 of the left robot unit 3 may interfere with the chuck 242 of the right end effector 24 of the right robot unit 2 which is in a standby position. Alternatively, it may interfere with the workpiece W held by the chucks 242 and 243.

[0070] Therefore, in order to prevent interference with the chuck portion 242 of the right end effector 24 or the workpiece W, the left robot unit 3 needs to restrict the tilt of the left first arm 31 from the +Y direction to the -X side by a value greater than the tilt angle θ1 of the tangent line L3 shown in Figure 5(B) from the +Y direction. Here, the tangent line L3 is the tangent line extending from the left first rotation axis center C1 of the left actuator 52 that rotates the left first arm 31 toward the +X side portion of the outer circumference of the left first joint portion 32. Although not shown, the right robot unit 2 also needs to restrict the right first arm 21, although it is in a positional relationship with the left robot unit 3 that is the opposite of the left robot unit 3.

[0071] Furthermore, as shown in Figure 5(C), if the left robot unit 3 retracts the left end effector 34 too far, the left first arm 31 will only be slightly tilted from the -Y direction to the -X direction. As a result, the left first joint 32 of the left robot unit 3 may interfere with the connecting portion 241 of the right end effector 24 of the right robot unit 2, which is in a standby position.

[0072] Therefore, in order to prevent interference with the connecting portion 241 of the right end effector 24, the left robot unit 3 needs to restrict the tilt of the left first arm 31 from the -Y direction to the -X side by a value greater than the tilt angle θ2 from the -Y direction of the tangent L4 shown in Figure 5(D). Here, the tangent L4 is the tangent extending from the left first rotation axis center C1 of the left actuator 52 that rotates the left first arm 31 toward the +X side portion of the outer circumference of the left first joint 32. Although not shown, the right robot unit 2 also needs to restrict the right first arm 21 in the same way as the left robot unit 3.

[0073] To restrict the movement of the left first arm 31 of the left robot section 3 and the right first arm 21 of the right robot section 2, the horizontal articulated robot 1 is provided with a stopper mechanism. Next, the configuration of the stopper mechanism will be explained with reference to Figure 6. Note that the stopper mechanisms of the left robot section 3 and the right robot section 2 have the same configuration except that they are symmetrical; therefore, the stopper mechanism of the right robot section 2 will be explained below, and the explanation of the stopper mechanism of the left robot section 3 will be omitted.

[0074] Figure 6(A) is an enlarged right side view of the horizontal articulated robot 1. Figure 6(B) is a top view showing an example of the stopper mechanism when the right robot unit 2 moves the right end effector 24 forward. Figure 6(C) is a top view showing an example of the stopper mechanism when the right robot unit 2 moves the right end effector 24 backward.

[0075] The right robot section 2 is equipped with cylindrical stoppers 61-63 as a stopper mechanism, as shown in Figures 6(A)-6(C).

[0076] In detail, the base 5 has stoppers 61 and 62 as shown in Figures 6(B) and 6(C). In contrast, the right first arm 21 of the right robot unit 2 has a stopper 63.

[0077] As shown in Figure 6(A), a gap 65 is provided between the upper surface of the base 5 and the lower surface of the right first arm 21 of the right robot unit 2. Stopper 61 protrudes upward from the upper surface of the base 5 toward the right first arm 21 of the right robot unit 2 within this gap 65. Stopper 62, although not shown in Figure 6(A), protrudes from the upper surface of the base 5 in the same manner as stopper 61. In contrast, stopper 63 protrudes downward from the lower surface of the right first arm 21 of the right robot unit 2 toward the base 5 within the aforementioned gap 65. The vertical lengths of stoppers 61, 62 and stopper 63 are greater than half the gap 65, and as a result, if stoppers 61, 62 and stopper 63 were located at the same position in the front-to-back and left-to-right directions, they would interfere with each other.

[0078] As shown in Figures 6(B) and 6(C), these stoppers 61, 62 and stopper 63 are provided on the circumference of a circle with radius R from the center C2 of the right first rotation axis of the right actuator 51 that rotates the right first arm 21 of the right robot unit 2. Furthermore, as shown in Figure 6(B), stoppers 61 and 62 are provided at both ends of an angle θ3 range centered on the center C2 of the right first rotation axis of the right actuator 51.

[0079] Here, angle θ3 is the angle that satisfies the relationship θ3 = 180° - (θ1 + θ2), where θ1 is the inclination angle θ1 explained with reference to Figure 5(B) and θ2 is the inclination angle θ2 explained with reference to Figure 5(D).

[0080] In contrast, the stopper 63 is positioned so that when the right first arm 21 of the right robot unit 2 rotates to a position corresponding to the left first arm 31 of the left robot unit 3 shown in Figure 5(B), it comes into contact with the stopper 63, as shown in Figure 6(B). This prevents the right robot unit 2 from rotating its right first arm 21 forward and to the left of the position corresponding to the left first arm 31 of the left robot unit 3 shown in Figure 5(B), i.e., to the +Y and -X sides, thereby preventing the right end effector 24 from moving excessively forward. As a result, the stopper 63 prevents the right first joint 22 of the right robot unit 2 from interfering with the workpiece W held by the left end effector 34 of the left robot unit 3.

[0081] Furthermore, the stopper 63 is positioned so that it contacts the stopper 62, as shown in Figure 6(C), when the right first arm 21 of the right robot unit 2 rotates to a position corresponding to the left first arm 31 of the left robot unit 3 shown in Figure 5(D). This prevents the stopper 63 from rotating the right first arm 21 of the right robot unit 2 further back and to the left than the position corresponding to the left first arm 31 of the left robot unit 3 shown in Figure 5(D), i.e., to the -Y and -X sides, thereby preventing the right end effector 24 from retracting excessively. As a result, the stopper 63 prevents the right first joint 22 of the right robot unit 2 from interfering with the connecting portion 341 of the left end effector 34 of the left robot unit 3.

[0082] Thus, the right robot unit 2 has stoppers 61-63 to prevent the right first joint 22 from interfering with the left end effector 34 of the left robot unit 3 or the workpiece W held by the left end effector 34. Although not shown, the left robot unit 3 also has three stoppers that are symmetrical in shape and arrangement to the stoppers 61-63, thereby preventing the left first joint 32 from interfering with the right end effector 24 of the right robot unit 2 or the workpiece W held by the right end effector 24.

[0083] In this embodiment, stoppers 61 and 62 are provided on the base 5, and stopper 63 is provided on the right first arm 21 of the right robot unit 2, or on the left first arm 31 of the left robot unit 3. However, stoppers 61 and 62 may be provided on the right first arm 21 of the right robot unit 2, or on the left first arm 31 of the left robot unit 3, and stopper 63 may be provided on the base 5.

[0084] As described above, in the horizontal articulated robot 1 according to this embodiment, the right first arm 21 of the right robot section 2 and the left first arm 31 of the left robot section 3 are positioned on the base 5. Therefore, regardless of the position of the base 5 when raised or lowered by the lifting device 4, the right first arm 21 and the left first arm 31 do not interfere with the base 5 even when they rotate. As a result, it is not necessary to position the base 5 away from the lifting device 4 in the front-to-back or left-to-right direction to prevent interference with the base 5. Consequently, the horizontal articulated robot 1 according to this embodiment is compact despite being capable of raising and lowering.

[0085] Furthermore, the chucks 242 and 243 of the right end effector 24 of the right robot section 2 are positioned below the right second arm 23 and above the right first arm 21, while the chucks 342 and 343 of the left end effector 34 of the left robot section 3 are positioned below the left second arm 33 and above the left first arm 31. As a result, the chucks 242 and 243 are positioned between the right second arm 23 and the right first arm 21, and the chucks 342 and 343 are positioned between the left second arm 33 and the left first arm 31. Thus, the horizontal articulated robot 1 according to this embodiment has a low pass line despite the base 5 being vertically movable and the horizontal articulated robot 1 itself being compact.

[0086] Furthermore, the chuck portions 242 and 243 of the right end effector 24 are positioned higher than the chuck portions 342 and 343 of the left end effector 34. Therefore, even when the right end effector 24 and the left end effector 34 move simultaneously in the same direction, for example, simultaneously forward or backward, the chuck portions 242 and 243 of the right end effector 24 and the chuck portions 342 and 343 of the left end effector 34 do not interfere with each other. As a result, the horizontal articulated robot 1 can transport the workpiece W simultaneously in the same direction.

[0087] In the horizontal articulated robot 1 according to this embodiment, the right second arm 23 of the right robot section 2 and the left second arm 33 of the left robot section 3 are positioned at the same height in the vertical direction. The thickness of the connecting section 241 that positions the chuck sections 242 and 243 of the right end effector 24 of the right robot section 2 below the right second arm 23 is smaller than the thickness of the connecting section 341 that positions the chuck sections 342 and 343 of the left end effector 34 of the left robot section 3 below the left second arm 23. Specifically, the thickness obtained by subtracting the thickness T3 of the horizontal section shown in Figure 3 from the thickness T1 of the right end effector 24 is smaller than the thickness obtained by subtracting the thickness T3 of the horizontal section from the thickness T2 of the left end effector 34. As a result, the chuck sections 242 and 243 of the right end effector 24 are positioned above the chuck sections 342 and 343 of the left end effector 34. In the horizontal articulated robot 1, this arrangement prevents interference between the chucks 242 and 243 of the right end effector 24 and the chucks 342 and 343 of the left end effector 34. As a result, the horizontal articulated robot 1 can simultaneously transport the workpiece W in the same direction.

[0088] Furthermore, in the horizontal articulated robot 1 according to this embodiment, the base 5 has a right actuator 51 and a left actuator 52, and the base 5 is rotatable. There is no need to provide the right actuator 51 and the left actuator 52 inside the right first arm 21 and right second arm 23 of the right robot section 2 and inside the left first arm 31 and left second arm 33 of the left robot section 3, and there is no need to provide a rotation mechanism to rotate the right robot section 2 and the left robot section 3 themselves. As a result, the right robot section 2 and the left robot section 3 can be made smaller in the horizontal articulated robot 1. In addition, since the right robot section 2 and the left robot section 3 can be made lighter, the moment of inertia of the right robot section 2 and the left robot section 3 is small, and the energy consumption of the horizontal articulated robot 1 can be reduced.

[0089] Furthermore, in the horizontal articulated robot 1 according to this embodiment, stoppers 61 and 62 are provided on the upper surface of the base 5, and a stopper 63 is provided on the lower surface of the base of the right first arm 21 of the right robot section 2. The stopper 63 contacts the stopper 61 or 62 before the right first joint 22 at the tip of the right first arm 21 interferes with the workpiece W or left end effector 34 held by the left robot section 3 when the right first arm 21 rotates, thereby restricting the rotation of the right first arm 21. As a result, the horizontal articulated robot 1 can prevent the right robot section 2 from colliding with the left robot section 3 or the workpiece W.

[0090] Furthermore, in the horizontal articulated robot 1, stoppers 61-63 with a similar configuration are also provided on the upper surface of the base 5 where the left robot section 3 is positioned, and on the lower surface of the base of the left first arm 31 of the left robot section 3, thereby preventing the left robot section 3 from colliding with the right robot section 2 or the workpiece W.

[0091] Of the configuration of the horizontal articulated robot 1 described above, the right first joint 22 and the left first joint 32 are examples of the right and left joints as defined in the claims. Also, the connecting part 241 and chuck parts 242 and 243 of the right end effector 24 are examples of the right connecting part and right chuck part as defined in the claims. The connecting part 341 and chuck parts 342 and 343 of the left end effector 34 are examples of the left connecting part and left chuck part as defined in the claims. Furthermore, the stopper 63 and stoppers 61 and 62 are examples of the right stopper and right projection as defined in the claims. Also, the stopper 63 and stoppers 61 and 62 provided on the left robot part 3 are examples of the left stopper and left projection as defined in the claims.

[0092] The above describes a horizontal articulated robot 1 according to an embodiment of the present invention, but the present invention is not limited to the above embodiment. For example, in the above embodiment, the chuck portions 242 and 243 of the right end effector 24 provided on the right robot section 2 are positioned above the chuck portions 342 and 343 of the left end effector 34 provided on the left robot section 3. However, the present invention is not limited to this. In the present invention, the positional relationship between the chuck portions 242 and 243 of the right end effector 24 and the chuck portions 342 and 343 of the left end effector 34 may be reversed. That is, the right robot section 2 and the left robot section 3 may be reversed left and right.

[0093] In this specification, the left-right direction refers to the direction perpendicular to the front-back direction and the up-down direction, where the direction in which the right robot unit 2 and the left robot unit 3 move the right end effector 24 or the left end effector 34 forward or backward is defined as the front-back direction, and the direction in which the lifting device 4 moves up and down is defined as the up-down direction. Therefore, even when the base 5 rotates along the horizontal plane, the direction in which the right robot unit 2 and the left robot unit 3 are aligned is the left-right direction.

[0094] Furthermore, in the above embodiment, the right end effector 24 has two chuck portions 242 and 243, and the left end effector 34 has two chuck portions 342 and 343. However, the present invention is not limited thereto, and the number of chuck portions 242 and 243 is arbitrary. For example, the right end effector 24 and the left end effector 34 may each have one chuck portion 242 or 342. Also, in the above embodiment, the chuck portions 242 and 243 and 342 and 343 are rod-shaped, but the present invention is not limited thereto, and the shape of the chuck portions 242 and 243 is also arbitrary. The chuck portions 242 and 243 and 342 and 343 may be, for example, flat plates. Furthermore, in the above embodiment, the chuck portions 242 and 243 and 342 and 343 hold the workpiece W by a suction mechanism, but the present invention is not limited thereto, and the means for holding the workpiece W is arbitrary.

[0095] In the above embodiment, an example was described in which the workpiece W is a rectangular glass plate, but in the present invention, the material and shape of the workpiece W are arbitrary. For example, the workpiece W may be a semiconductor wafer. The present invention is broadly applicable to horizontal articulated robots 1 that transport objects.

[0096] The present invention allows for various embodiments and modifications without departing from the broad spirit and scope of the invention. Furthermore, the embodiments described above are for illustrative purposes only and do not limit the scope of the invention. In other words, the scope of the invention is indicated by the claims, not by the embodiments. Various modifications made within the scope of the claims and the equivalent significance of disclosure are considered to be within the scope of the invention. [Explanation of symbols]

[0097] 1…Horizontal articulated robot, 2…Right robot section, 3…Left robot section, 4…Lifting device, 5…Base, 21…Right first arm, 22…Right first joint section, 23…Right second arm, 24…Right end effector, 31…Left first arm, 32…Left first joint section, 33…Left second arm, 34…Left end effector, 41, 42, 43, 44…Cylinder, 51…Right actuator, 52…Left actuator, 61-63…Stopper, 65…Gap, 100…Horizontal articulated robot, 101…First arm, 102…Right second arm, 103…Right end effector, 104…Left second arm, 105…Left end Effector, 115...base, 150-152...actuator, 241...connecting part, 242,243...chuck part, 341...connecting part, 342,343...chuck part, 422...screw shaft, 423...nut, 425...belt, 432...screw shaft, 433...nut, 434...ball spline, 435,436...belt, 441...motor, 442...screw shaft, 443...nut, 444...ball spline, 445,446...belt, C...center, H1...height, L1,L2...length, L3,L4...tangent, T1-T3...thickness, θ1,θ2...inclination angle, θ3...angle, R...radius, W...workpiece

Claims

1. A horizontal articulated robot comprising a base that can be raised and lowered by a lifting device, and a right robot section and a left robot section mounted on the base and arranged in the left-right direction, The base has a right first pivot axis and a left first pivot axis arranged in the left-right direction and extending in the up-down direction, The aforementioned right robot section is The base is positioned on the base and connected to the right first pivot shaft, and the tip of the right first arm pivots as the right first pivot shaft rotates, A columnar right joint portion extending upward from the tip of the right first arm, The base of the right second arm is positioned on the right joint and connected to the right second pivot axis of the right joint, and the tip of the right second arm rotates as the right second pivot axis rotates, It has a right chuck portion for chucking a workpiece, and a right end effector provided on the lower side of the tip of the right second arm, Equipped with, The left robot section is, The base is positioned on the base and connected to the left first pivot axis, and the tip of the left first pivot axis rotates as the left first pivot axis rotates, A columnar left joint portion extending upward from the tip of the left first arm, The base of the left second arm is positioned on the left joint and connected to the left second pivot axis of the left joint, and the tip of the left second arm rotates as the left second pivot axis rotates, A left chuck portion for chucking a workpiece is provided, and a left end effector is located on the lower side of the tip of the left second arm, Equipped with, The right chuck portion is positioned below the right second arm and above the right first arm. The left chuck portion is positioned below the left second arm and above the left first arm. Either the right chuck portion or the left chuck portion is positioned above the other of the right chuck portion or the left chuck portion. Horizontal articulated robot.

2. The right second arm and the left second arm are positioned at the same height in the vertical direction. The right end effector has a right connecting portion that connects to the tip of the right second arm and positions the right chuck portion below the right second arm. The left end effector has a left connecting portion that connects to the tip of the left second arm and positions the right chuck portion below the left second arm. Either the right chuck portion or the left chuck portion is positioned above the other of the right chuck portion because the vertical thickness of either the right connecting portion or the left connecting portion is smaller than the vertical thickness of the other of the right connecting portion or the left connecting portion. A horizontal articulated robot according to claim 1.

3. The lifting device has a telescopic mechanism that can extend and retract vertically. The aforementioned base is, It comprises a right actuator that drives the right first arm and the right second arm, and a left actuator that drives the left first arm and the left second arm, Displaced on the telescopic mechanism and capable of rotating on the telescopic mechanism, A horizontal articulated robot according to claim 1 or 2.

4. A right stopper is provided which, by projecting from either the base or the base of the right first arm toward the other part of the base or the base of the right first arm, and by contacting a right projection provided on the other part, restricts the rotation of the right first arm by the right first pivot axis. A left stopper is provided which extends from either the base or the base of the left first arm toward the other part of the base or the base of the left first arm, and contacts a left projection provided on the other part, thereby restricting the rotation of the left first arm by the left first pivot axis. Furthermore, The right stopper, when the tip of the right first arm rotates due to the rotation of the right first pivot axis, contacts the right projection before the right joint portion at the tip of the right first arm interferes with the workpiece or the left end effector chucked by the left chuck portion, thereby restricting the rotation of the right first arm by the right first pivot axis. The left stopper, when the tip of the left first arm rotates due to the rotation of the left first pivot axis, contacts the left projection before the left joint portion at the tip of the left first arm interferes with a workpiece other than the workpiece chucked by the right chuck portion or with the right end effector, thereby restricting the rotation of the left first arm by the left first pivot axis. A horizontal articulated robot according to claim 1.

Images