Horizontal articulated robot

Abstract

To provide a horizontal articulated robot that can effectively suppress deterioration of operational performance. [Solution] The horizontal articulated robot comprises a main frame, a first subframe, a plurality of first support columns connecting the main frame and the first subframe, a second subframe, a second support column connecting the first subframe and the second subframe, and a first motor and a second motor located on the first subframe. The first motor and the second motor are arranged in a direction perpendicular to the second rotation axis, which is the rotation axis of the second arm, and the second support column 45 is located between the plurality of first support columns or within the region enclosed by the plurality of first support columns in a plan view from the direction along the second rotation axis.

Description

Technical Field

[0001] The present invention relates to an articulated robot.

Background Art

[0002] The scalar robot described in Patent Document 1 includes a base unit, an arm rotatably attached to the base unit, and a rotation / linear movement mechanism provided at the tip of the arm.

[0003] The rotation / linear movement mechanism has a main frame installed at the tip of the arm via a bearing. A motor for rotating the rotation / linear movement mechanism and a speed reducer for rotating the rotation / linear movement mechanism are installed at the base end of the main frame. By driving the motor for rotating the rotation / linear movement mechanism, the rotation / linear movement mechanism rotates with respect to the arm via the speed reducer for rotating the rotation / linear movement mechanism.

[0004] A ball spline nut through which a ball screw spline shaft is inserted is installed at the tip of the main frame. A motor for rotating the ball spline nut is installed on the main frame. Therefore, by driving the motor for rotating the ball spline nut, the ball spline nut rotates and the ball screw spline shaft rotates.

[0005] A sub-frame is installed on the main frame via a plurality of columns. If the main frame is the first floor part, the sub-frame is the second floor part. A ball screw nut through which a ball screw spline shaft is inserted is installed on the sub-frame. A motor for rotating the ball screw nut is installed on the sub-frame. Therefore, by driving the motor for rotating the ball screw nut, the ball screw nut rotates and the ball screw spline shaft moves up and down.

[0006] As described above, by providing a first floor with the main frame as the floor surface and a second floor with the subframe as the floor surface, vertical space is secured for arranging each part that constitutes the rotation and linear movement mechanism. This configuration is particularly effective when the overall length of the rotation and linear movement mechanism is relatively short and internal space tends to be insufficient. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2020-142309 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, in the SCARA robot described in Patent Document 1, the motor for rotating the ball spline nut and the motor for rotating the ball screw nut are arranged separately on the main frame and subframe, and are positioned so that they overlap each other vertically. As a result, the overall height of the rotation and linear movement mechanism becomes high, which makes it easier for unwanted vibrations to occur due to the inertial force during rotation. Consequently, the operating performance deteriorates. [Means for solving the problem]

[0009] The present invention comprises a horizontal articulated robot and a base, A first arm connected to the base and rotating around a first pivot axis relative to the base, A second arm connected to the first arm and rotating relative to the first arm around a second pivot axis, The second arm is positioned and has a shaft that rotates relative to the second arm around a third pivot axis and moves along the third pivot axis, The aforementioned second arm is connected to the main frame, A first subframe is positioned spaced apart from the main frame in a direction along the second pivot axis, A plurality of first support columns are located between the main frame and the first subframe and connect the main frame and the first subframe, A second subframe is spaced apart from the first subframe in the direction along the second pivot axis and is located on the opposite side of the main frame from the first subframe, A second support column is located between the first subframe and the second subframe and connects the first subframe and the second subframe, A first motor is positioned on the first subframe and rotates the shaft around the third pivot axis, It includes a second motor positioned on the first subframe and moving the shaft along the third pivot axis, The first motor and the second motor are arranged side by side in a direction perpendicular to the second pivot shaft, The second support column is positioned between the multiple first support columns, or within the region enclosed by the multiple first support columns, in a plan view from a direction along the second pivot axis. [Brief explanation of the drawing]

[0010] [Figure 1] This is a side view showing a robot according to the first embodiment. [Figure 2] This is a cross-sectional view showing the connection between the base and the first arm. [Figure 3] This is a perspective view showing the internal structure of the second arm. [Figure 4] This is a side view showing the shaft rotation mechanism. [Figure 5] This is a side view showing a shaft linear motion mechanism. [Figure 6] This is a top view illustrating the arrangement of the first support column. [Figure 7] This is a top view illustrating the arrangement of the second support column. [Figure 8] This is a top view showing the internal structure of the second arm of the robot according to the second embodiment. [Modes for carrying out the invention]

[0011] Hereinafter, the horizontal articulated robot of the present invention will be described in detail based on the embodiments shown in the accompanying drawings.

[0012] <First Embodiment> FIG. 1 is a side view showing the robot according to the first embodiment. FIG. 2 is a cross-sectional view showing the connecting portion between the base and the first arm. FIG. 3 is a perspective view showing the internal structure of the second arm. FIG. 4 is a side view showing the shaft rotation mechanism. FIG. 5 is a side view showing the shaft linear motion mechanism. FIG. 6 is a top view for explaining the arrangement of the first support column. FIG. 7 is a top view for explaining the arrangement of the second support column.

[0013] Note that the vertical direction in FIG. 1 coincides with the vertical direction. Therefore, hereinafter, the upper side in FIG. 1 will also be referred to as "up" and the lower side as "down". Also, in this specification, "vertical" means not only when it coincides with the vertical, but also when it is inclined with respect to the vertical within a range where the effects of the present invention can be exhibited, for example, when it is inclined within ±5° with respect to the vertical. Similarly, in this specification, "parallel" means not only when two objects coincide with each other, but also when they are inclined from parallel within a range where the effects of the present invention can be exhibited, for example, when they are inclined within ±5° with respect to parallel.

[0014] The horizontal articulated robot 1 shown in Fig. 1 is also called a scalar robot, and includes a base 2 fixed to the floor, a first arm 3 rotatably connected to the base 2 around a first rotation axis J1, a second arm 4 rotatably connected to the first arm 3 around a second rotation axis J2, a duct 5 connecting the base 2 and the second arm 4, a work head 6 disposed on the second arm 4, a first arm drive mechanism 7 for rotating the first arm 3 around the first rotation axis J1 with respect to the base 2, a second arm drive mechanism 8 for rotating the second arm 4 around the second rotation axis J2 with respect to the first arm 3, a work head drive mechanism 9 for driving the work head 6, and a control device 10 for controlling the drives of the first arm drive mechanism 7, the second arm drive mechanism 8 and the work head drive mechanism 9.

[0015] As shown in Fig. 1, the first arm 3 is connected to the base 2 at its base end and rotates around the first rotation axis J1 with respect to the base 2. The first rotation axis J1 is along the vertical direction.

[0016] As shown in Fig. 2, the first arm drive mechanism 7 includes a speed reducer 71 that rotatably connects the base 2 and the first arm 3, and an encoder-integrated motor 72 disposed in the base 2. The speed reducer 71 is a harmonic gear device, where the circular spline 711 is fixed to the base 2 and the flex spline 712 is fixed to the first arm 3. Also, the main body of the motor 72 is fixed to the circular spline 711, and the output shaft 721 of the motor 72 is fixed to the wave generator 713. Therefore, as the output shaft 721 rotates, the wave generator 713 rotates, and further, the flex spline 712 rotates at a predetermined reduction ratio with respect to the rotation of the wave generator 713. As a result, the first arm 3 rotates around the first rotation axis J1 with respect to the base 2. However, the configuration of the first arm drive mechanism 7 is not particularly limited.

[0017] As shown in Fig. 1, the second arm 4 is connected to the first arm 3 at its base end and rotates around the second rotation axis J2 with respect to the first arm 3. The second rotation axis J2 is along the vertical direction and is parallel to the first rotation axis J1.

[0018] Furthermore, as shown in Figures 1 and 3, the second arm 4 includes a main frame 41 connected to the tip of the first arm 3, a first subframe 42 located above the main frame 41, a plurality of first support columns 43 connecting the main frame 41 and the first subframe 42, a second subframe 44 located above the first subframe 42, a plurality of second support columns 45 connecting the first subframe 42 and the second subframe 44, and a cover 46 placed over the main frame 41 from above the second subframe 44.

[0019] In other words, the second arm 4 is located between the main frame 41 and the first subframe 42, and has a first floor portion with the main frame 41 as the floor surface; a second floor portion located between the first subframe 42 and the second subframe 44, and has the first subframe 42 as the floor surface; and a third floor portion located above the second subframe 44, and has the second subframe 44 as the floor surface. With this configuration, the installation space for each part placed inside the second arm 4 is secured in multiple stages vertically, making it a particularly effective configuration when the overall length of the second arm 4 is short and internal installation space tends to be insufficient.

[0020] For example, the main frame 41 and the first subframe 42 are each made of castings using metal materials such as aluminum, and are formed relatively thick to obtain sufficient rigidity. In contrast, the second subframe 44 is made of sheet metal (thin metal plate material) made of metal materials such as steel, stainless steel, or aluminum. With this configuration, the weight of the second subframe 44 can be reduced, and the center of gravity of the second arm 4 can be positioned lower. As a result, vibrations of the second arm 4 can be effectively suppressed. However, the constituent materials and manufacturing methods of the main frame 41, the first subframe 42, and the second subframe 44 are not particularly limited.

[0021] Furthermore, there are five first support columns 43, each being a straight rod extending vertically. These five first support columns 43 are located between the main frame 41 and the first subframe 42, and are connected to them at both the upper and lower ends. The arrangement of the five first support columns 43 will be described in detail later. Additionally, there are two second support columns 45, each being a straight rod extending vertically. These two second support columns 45 are located between the first subframe 42 and the second subframe 44, and are connected to them at both the upper and lower ends. The arrangement of the two second support columns 45 will be described in detail later.

[0022] Furthermore, as shown in Figure 3, the second subframe 44 is equipped with multiple connectors C and a brake release button B for releasing the brake 923, which will be described later. The connectors C include a connector C1 for compressed air, and connectors C2 for electrical signals such as D-sub and Ethernet. These connectors C and the brake release button B are exposed to the outside of the second arm 4 without being covered by the cover 46.

[0023] The second arm drive mechanism 8 has the same configuration as the first arm drive mechanism 7. As shown in Figure 3, the second arm drive mechanism 8 includes a reduction gear 81 that rotatably connects the first arm 3 and the second arm 4, and an encoder-integrated motor 82 located within the second arm 4. Although not shown, the reduction gear 81 is a harmonic drive gear similar to the reduction gear 71, with a circular spline fixed to the main frame 41 and a flexspline fixed to the first arm 3. The body of the motor 82 is fixed to the circular spline, and the output shaft of the motor 82 is fixed to the wave generator. Therefore, the wave generator rotates along with the rotation of the output shaft, and furthermore, the flexspline rotates in response to the rotation of the wave generator at a predetermined reduction ratio. As a result, the second arm 4 rotates around the second pivot axis J2 relative to the first arm 3. However, the configuration of the second arm drive mechanism 8 is not particularly limited.

[0024] As shown in Figure 3, the work head 6 is positioned at the tip of the second arm 4. The work head 6 has a spline nut 61 and a ball screw nut 62 arranged coaxially in a vertical direction, and a ball screw spline shaft 63 which is a shaft inserted through the spline nut 61 and the ball screw nut 62. In such a work head 6, when the spline nut 61 is rotated, the ball screw spline shaft 63 rotates around its central axis, the third pivot axis J3, and when the ball screw nut 62 is rotated, the ball screw spline shaft 63 moves linearly (up and down) along the third pivot axis J3. The third pivot axis J3 is oriented vertically and is parallel to the first pivot axis J1 and the second pivot axis J2.

[0025] Although not shown in the diagram, an end effector, depending on the task, is attached to the lower end of the ball screw spline shaft 63.

[0026] As shown in Figure 3, the work head drive mechanism 9 includes a shaft rotation mechanism 91 that rotates the spline nut 61 to rotate the ball screw spline shaft 63 around the third rotation axis J3, and a shaft linear motion mechanism 92 that rotates the ball screw nut 62 to move the ball screw spline shaft 63 in a linear direction along the third rotation axis J3.

[0027] As shown in Figure 4, the shaft rotation mechanism 91 includes a first motor 911 with a built-in encoder located within the second arm 4, and a transmission mechanism 912 that transmits the driving force of the first motor 911 to the spline nut 61.

[0028] The transmission mechanism 912 includes a first motor-side pulley 912a fixed to the output shaft 911a of the first motor 911, a first shaft-side pulley 912b fixed to a spline nut 61, and a first belt 912c wrapped around the first motor-side pulley 912a and the first shaft-side pulley 912b. In this configuration, the rotation of the output shaft 911a is transmitted to the first shaft-side pulley 912b via the first motor-side pulley 912a and the first belt 912c, causing the first shaft-side pulley 912b and the spline nut 61 to rotate together around the third pivot axis J3. As a result, the ball screw spline shaft 63 rotates around the third pivot axis J3. In this embodiment, the first shaft-side pulley 912b has a larger diameter than the first motor-side pulley 912a, and the transmission mechanism 912 functions as a reduction gear, so the spline nut 61 rotates at a predetermined reduction ratio in response to the rotation of the output shaft 911a.

[0029] Furthermore, the shaft rotation mechanism 91 has a first motor holding member 914 that holds the first motor 911 and pivotally supports the first motor-side pulley 912a. The first motor 911 is fixed to the second subframe 44 via the first motor holding member 914. When fixed to the second subframe 44, the first motor 911 is located on the second floor of the second arm 4, that is, between the main frame 41 and the first subframe 42, with the output shaft 911a facing vertically downward. In addition, a first through hole 421 is formed in the first subframe 42, penetrating its upper and lower surfaces, and the output shaft 911a of the first motor 911 is inserted through the first through hole 421. Therefore, the output shaft 911a faces the first floor, and the first motor-side pulley 912a, which is fixed to the output shaft 911a, is located on the first floor.

[0030] As shown in Figure 5, the shaft linear motion mechanism 92 includes a second motor 921 with a built-in encoder located in the second arm 4, a transmission mechanism 922 that transmits the driving force of the second motor 921 to the ball screw nut 62, and a brake 923.

[0031] The transmission mechanism 922 includes a second motor-side pulley 922a fixed to the output shaft 921a of the second motor 921, a second shaft-side pulley 922b fixed to a ball screw nut 62, and a second belt 922c wrapped around the second motor-side pulley 922a and the second shaft-side pulley 922b. In this configuration, the rotation of the output shaft 921a is transmitted to the second shaft-side pulley 922b via the second motor-side pulley 922a and the second belt 922c, causing the second shaft-side pulley 922b and the ball screw nut 62 to rotate together around the third pivot shaft J3. As a result, the ball screw spline shaft 63, which has a helical groove, rotates around the third pivot shaft J3 while moving linearly along the third pivot shaft J3. In this embodiment, the second shaft-side pulley 922b has a larger diameter than the second motor-side pulley 922a, and the transmission mechanism 922 functions as a reduction gear, so the ball screw nut 62 rotates with respect to the rotation of the output shaft 921a at a predetermined reduction ratio.

[0032] Furthermore, the brake 923 is an electromagnetic brake coaxially connected to the second motor side pulley 922a, and by controlling the ON / OFF of the power supply, it switches between a brake state that restricts the rotation of the second motor side pulley 922a and a brake release state that allows the rotation of the second motor side pulley 922a.

[0033] Furthermore, the shaft linear motion mechanism 92 has a second motor holding member 924 that holds the second motor 921 and pivotally supports the second motor-side pulley 922a via a brake 923. The second motor 921 is fixed to the second subframe 44 via the second motor holding member 924. When fixed to the second subframe 44, the second motor 921 is located on the second floor of the second arm 4, with the output shaft 921a facing vertically downward. In addition, a second through hole 422 is formed in the first subframe 42, penetrating its upper and lower surfaces, and the output shaft 921a of the second motor 921 is inserted through the second through hole 422. As a result, the output shaft 921a faces the first floor, and the second motor-side pulley 922a fixed to the output shaft 921a and the brake 923 connected to the second motor-side pulley 922a are each located on the first floor.

[0034] Here, the pulleys 912a and 922a on the first and second motor sides, and the brake 923, are shorter in the vertical direction than the first and second motors 911 and 921. Therefore, as mentioned above, by positioning the pulleys 912a and 922a on the first and second motor sides, and the brake 923, on the first floor, that is, between the main frame 41 and the first subframe 42, the space on the first floor can be used efficiently, and the height of the first floor can be reduced, resulting in a lower installation position for the first and second motors 911 and 921. As a result, the center of gravity of the second arm 4 is kept low, and deformation of the second arm 4 due to inertial force during rotation can be effectively suppressed, making it less likely for unwanted vibrations to occur. As a result, deterioration of operational performance, such as a decrease in the positional accuracy and cycle time of the horizontal articulated robot 1, can be effectively suppressed. However, the arrangement of the pulleys 912a and 922a on the first and second motor sides, and the brake 923, is not particularly limited and may be placed on the second floor.

[0035] The above describes the work head drive mechanism 9, but the configuration of the work head drive mechanism 9 is not particularly limited.

[0036] As shown in Figure 1, the duct 5 is a tubular member that directly connects the base 2 and the second arm 4 without passing through the first arm 3. Although not shown, multiple wires and pipes are routed from the base 2 to the second arm 4 via the duct 5, and these wires and pipes are connected to the connector C, brake release button B, brake 923, motor 82, first motor 911, second motor 921, etc.

[0037] Furthermore, as shown in Figure 3, the tip of the duct 5, that is, the end on the second arm 4 side, is supported by the second subframe 44. The connection point of the duct 5 to the second subframe 44 is located at the base end of the second subframe 44, and is located on the base end side of the tip-side region where the connector C and brake release button B are located. With this configuration, wiring to the connector C, connecting piping, and pressing the brake release button B are less likely to be obstructed by the duct 5, improving the operability and safety of the horizontal articulated robot 1. In addition, the connection point of the duct 5 to the second subframe 44 overlaps with the second rotation axis J2. With this configuration, twisting of the duct 5 during the operation of the horizontal articulated robot 1 can be reduced.

[0038] As shown in Figure 1, the control device 10 is located within the base 2. The control device 10 independently and comprehensively controls the drives of motors 72, 82 and the first and second motors 911, 921. The control device 10 is composed of, for example, a computer and includes a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), etc. The above functions are achieved by the CPU reading and executing programs and data stored in the ROM. However, the configuration of the control device 10 is not particularly limited as long as it can control the drive of the horizontal articulated robot 1. Also, although the control device 10 is located within the base 2 in this embodiment, the location of the control device 10 is not particularly limited.

[0039] The overall configuration of the horizontal articulated robot 1 has been described above. Next, the arrangement of the first motor 911 and the second motor 921, and the arrangement of the first and second support columns 43 and 45 will be described in detail. For the sake of explanation, in the following, the direction along the central axis A of the second arm 4 will be referred to as the longitudinal direction, and the direction perpendicular to the central axis A and the vertical direction, in other words, the direction perpendicular to the plane defined by the second and third rotation axes J2 and J3, will be referred to as the short direction of the second arm 4. However, the central axis A is an axis that intersects with the second rotation axis J2 and the third rotation axis J3 and is perpendicular to the vertical direction.

[0040] As shown in Figure 3, the first motor 911 and the second motor 921 are both positioned on the second level of the second arm 4. Furthermore, as shown in Figure 6, the first motor 911 and the second motor 921 are positioned side by side in a direction perpendicular to the second pivot axis J2, that is, in the horizontal direction. By arranging the first and second motors 911 and 921 side by side in the horizontal direction in this way, the overall height of the second arm 4, that is, its vertical length, can be kept small. As a result, deformation of the second arm 4 due to inertial force during rotation can be effectively suppressed, and unwanted vibrations are less likely to occur. Consequently, deterioration of operational performance, such as a decrease in the positional accuracy and a decrease in cycle time of the horizontal articulated robot 1, can be effectively suppressed.

[0041] In particular, in this embodiment, the first motor 911 and the second motor 921 are arranged side by side in the short-side direction of the second arm 4. Therefore, even if the overall length of the second arm 4 is short, the first motor 911 and the second motor 921 can be arranged without difficulty. Note that "the first and second motors 911 and 921 are arranged side by side in the short-side direction of the second arm 4" means that at least a portion of the first and second motors 911 and 921 overlap each other when viewed from a plan view from the short-side direction of the second arm 4. Furthermore, the first motor 911 and the second motor 921 are located on opposite sides of the central axis A and are arranged symmetrically with respect to the central axis A. With this configuration, the bias of the center of gravity of the second arm 4 towards the short-side direction is suppressed, and the rotation of the second arm 4 around the second pivot axis J2 becomes smooth.

[0042] However, the arrangement of the first and second motors 911 and 921 is not limited to this. For example, the first and second motors 911 and 921 may be arranged side by side in the longitudinal direction of the second arm 4. Also, for example, the first and second motors 911 and 921 may both be arranged on one side of the central axis A.

[0043] Furthermore, the five first support columns 43 include a central support column 431 located between the first motor 911 and the second motor 921 in a plan view from the vertical direction, that is, in a plan view from the direction along the second rotation axis J2. In other words, one of the five first support columns 43 is the central support column 431. With this configuration, the relatively heavy first and second motors 911 and 921 can be stably supported. In addition, the deflection of the first subframe 42 can be effectively suppressed, and the posture of the first and second motors 911 and 921 can be stabilized. In particular, in this embodiment, the central support column 431 is located on the central axis A in a plan view from the vertical direction. Therefore, the aforementioned effects are more pronounced.

[0044] Furthermore, the statement that "the central support column 431 is located between the first motor 911 and the second motor 921" means, for example, that in a plan view from the vertical, the central support column 431 is located between a virtual straight line that is tangent to the first and second motors 911 and 921 from the tip side and a virtual straight line that is tangent to the first and second motors 911 and 921 from the base side.

[0045] Furthermore, the five first support columns 43 include a first tip support column 432 located on the tip side of the first motor 911, i.e., on the third rotation axis J3 side, and a first base support column 433 located on the base side of the first motor 911, i.e., on the second rotation axis J2 side, when viewed in a plan view from the vertical direction. In other words, one of the five first support columns 43 is the first tip support column 432 and one is the first base support column 433. When viewed in a plan view from the vertical direction, at least a part of the first motor 911, particularly the output shaft 911a, is located within a triangular region S1 connecting the central axes of the central support column 431, the first tip support column 432, and the first base support column 433. With this configuration, the posture of the first motor 911 is more stable, and deformation of the first subframe 42 caused by reaction forces from the first belt 912c can be effectively suppressed. Therefore, deterioration of the operational performance of the horizontal articulated robot 1 can be effectively suppressed.

[0046] Furthermore, the five first support columns 43 include a second tip support column 434 located on the tip side of the second motor 921, i.e., on the third rotation axis J3 side, and a second base support column 435 located on the base side of the second motor 921, i.e., on the second rotation axis J2 side, when viewed in a plan view from the vertical direction. In other words, one of the five first support columns 43 is the second tip support column 434 and one is the second base support column 435. When viewed in a plan view from the vertical direction, at least a part of the second motor 921, particularly the output shaft 921a, is located within a triangular region S2 that connects the central axes of the central support column 431, the second tip support column 434, and the second base support column 435. With this configuration, the posture of the second motor 921 is more stable, and deformation of the first subframe 42 caused by reaction forces from the second belt 922c can be effectively suppressed. Therefore, deterioration of the operational performance of the horizontal articulated robot 1 can be effectively suppressed.

[0047] In this embodiment, in a plan view from the vertical, the first tip support 432 and the first base support 433, and the second tip support 434 and the second base support 435 are arranged symmetrically with respect to the central axis A. In other words, in a plan view from the vertical, regions S1 and S2 are arranged symmetrically with respect to the central axis A.

[0048] The first support columns 43 have been described above, but the number of first support columns 43 is not limited to five; there may be two, three, four, or six or more. Furthermore, it is not necessary to have at least one of the central support column 431, the first end-side support column 432, the first base-side support column 433, the second end-side support column 434, and the second base-side support column 435.

[0049] Furthermore, the two second support columns 45 are each positioned between multiple first support columns 43 in a plan view from the vertical direction. Specifically, the two second support columns 45 include a first motor-side support column 451 positioned between the central support column 431 and the first base-side support column 433 in a plan view from the vertical direction, and a second motor-side support column 452 positioned between the central support column 431 and the second base-side support column 435. With this configuration, the first motor-side support column 451 is double-supported by the central support column 431 and the first base-side support column 433, and the second motor-side support column 452 is double-supported by the central support column 431 and the second base-side support column 435. Therefore, deformation and vibration of the first subframe 42 caused by external forces transmitted to the first subframe 42 via the first motor-side support column 451 and the second motor-side support column 452 can be effectively suppressed. Therefore, deterioration of the operational performance of the horizontal articulated robot 1 can be effectively suppressed.

[0050] Furthermore, when viewed from a vertical plane, "the first motor-side support column 451 is positioned between the central support column 431 and the first base-side support column 433" means, for example, that when viewed from a vertical plane, the line segment connecting the central axes of the central support column 431 and the first base-side support column 433 coincides with the first motor-side support column 451. Similarly, when viewed from a vertical plane, "the second motor-side support column 452 is positioned between the central support column 431 and the second base-side support column 435" means, for example, that when viewed from a vertical plane, the line segment connecting the central axes of the central support column 431 and the second base-side support column 435 coincides with the second motor-side support column 452.

[0051] Furthermore, the first and second motor-side support columns 451 and 452 are arranged symmetrically with respect to the central axis A in a plan view from the vertical direction. With this configuration, the second subframe 44 can be supported in a balanced manner from both ends in the short direction. Therefore, deformation and vibration of the second subframe 44 can be effectively suppressed.

[0052] Furthermore, the first and second motor-side support columns 451 and 452 are connected to the first subframe 42, respectively, and are not directly connected to the second arm drive mechanism 8. As a result, the first and second motor-side support columns 451 and 452 are less susceptible to vibrations from the second arm drive mechanism 8, particularly the reduction gear 81, and deformation and vibration of the second subframe 44 can be effectively suppressed.

[0053] Furthermore, as shown in Figure 7, the first and second motor-side supports 451 and 452 are located in the longitudinal center of the second arm 4 of the second subframe 44 in a plan view from the vertical direction. In other words, the first and second motor-side supports 451 and 452 are connected to the second subframe 44 at points closer to the center O than to the tip and base of the second subframe 44 in the longitudinal direction of the second arm 4. With this configuration, the first and second motor-side supports 451 and 452 can support the second subframe 44 in a balanced manner, and deformation and vibration of the second subframe 44 can be effectively suppressed.

[0054] In particular, in this embodiment, the first and second motor-side support columns 451 and 452 are each located on the base side of the center O, and in a plan view from the vertical, they are arranged in the short direction alongside the connection portion of the duct 5 to the second subframe 44. With this configuration, the first and second motor-side support columns 451 and 452 can be positioned near the connection portion of the second subframe 44 to the duct 5. This portion is susceptible to deformation due to stress caused by deformation of the duct 5 accompanying the rotation of the second arm 4. Therefore, by supporting this portion with the first and second motor-side support columns 451 and 452, deformation and vibration of the second subframe 44 can be effectively suppressed.

[0055] The horizontal articulated robot 1 has been described above. As previously mentioned, the horizontal articulated robot 1 includes a base 2, a first arm 3 connected to the base 2 and rotating relative to the base 2 around a first rotation axis J1, a second arm 4 connected to the first arm 3 and rotating relative to the first arm 3 around a second rotation axis J2, and a ball screw spline shaft 63 positioned on the second arm 4, which rotates relative to the second arm 4 around a third rotation axis J3 and moves along the third rotation axis J3. Furthermore, the second arm 4 comprises a main frame 41, a first subframe 42 positioned vertically away from the main frame 41 in a direction along the second rotation axis J2, that is, a plurality of first support columns 43 located between the main frame 41 and the first subframe 42 and connecting the main frame 41 and the first subframe 42, and a first support column 43 positioned vertically away from the first subframe 42 in a direction along the second rotation axis J2, that is, opposite the main frame 41 to the first subframe 42. The second subframe 4 includes a second subframe 44 located on the opposite side, a second support column 45 located between the first subframe 42 and the second subframe 44 and connecting the first subframe 42 and the second subframe 44, a first motor 911 located on the first subframe 42 that rotates the ball screw spline shaft 63 around the third pivot axis J3, and a second motor 921 located on the first subframe 42 that moves the ball screw spline shaft 63 along the third pivot axis J3. The first motor 911 and the second motor 921 are arranged side by side in the short direction, which is perpendicular to the second pivot axis J2, and the second support column 45 is located between multiple first support columns 43 in a plan view from the direction along the second pivot axis J2, that is, in a plan view from the vertical direction. With this configuration, the overall height of the second arm 4 can be kept low. Therefore, deformation of the second arm 4 due to inertial force during rotation can be effectively suppressed, making it less likely for unwanted vibrations to occur. Furthermore, deformation and vibration of the first subframe 42 caused by external forces transmitted to the first subframe 42 via the second support column 45 can also be effectively suppressed. As a result, deterioration of the operational performance of the horizontal articulated robot 1 can be effectively suppressed.

[0056] Furthermore, as mentioned above, the multiple first support columns 43 include a central support column 431 located between the first motor 911 and the second motor 921 in a plan view from a direction along the second rotation axis J2. With this configuration, the relatively heavy first and second motors 911 and 921 can be stably supported. In addition, deflection and vibration of the first subframe 42 can be effectively suppressed, and the posture of the first and second motors 911 and 921 can be stabilized.

[0057] Furthermore, as mentioned above, among the multiple first support columns 43, there is a first base support column 433 that is located on the second rotation axis J2 side of the first motor 911 when viewed from a plan view along the second rotation axis J2, and the second support column 45 is located between the central support column 431 and the first base support column 433. With this configuration, the second support column 45 is double-supported by the central support column 431 and the first base support column 433, and deformation and vibration of the first subframe 42 caused by external forces transmitted to the first subframe 42 via the second support column 45 can be effectively suppressed. As a result, deterioration of the operating performance of the horizontal articulated robot 1 can be effectively suppressed.

[0058] Furthermore, as mentioned above, the multiple first support columns 43 include a second base support column 435 that, in a plan view from the direction along the second rotation axis J2, is located closer to the second rotation axis J2 than the second motor 921, and the second support column 45 is located between the central support column 431 and the second base support column 435. With this configuration, the second support column 45 is double-supported by the central support column 431 and the second base support column 435, and deformation and vibration of the first subframe 42 caused by external forces transmitted to the first subframe 42 via the second support column 45 can be effectively suppressed. Therefore, deterioration of the operating performance of the horizontal articulated robot 1 can be effectively suppressed.

[0059] Furthermore, as mentioned above, the second support column 45 is located in the center of the second subframe 44 in the direction in which the second rotation axis J2 and the third rotation axis J3 are aligned, when viewed from a plan view along the second rotation axis J2. With this configuration, the second support column 45 can support the second subframe 44 in a balanced manner, and deformation and vibration of the second subframe 44 can be effectively suppressed.

[0060] Furthermore, as mentioned above, the horizontal articulated robot 1 has a duct 5 that connects the base 2 and the second arm 4 without passing through the first arm 3, and whose end on the second arm 4 side is supported by the second subframe 44. The second support column 45 is arranged in a plan view from the direction along the second rotation axis J2, aligned with the connection point of the duct 5 to the second subframe 44 and in a direction perpendicular to the second rotation axis J2, i.e., in the shorter direction. With this configuration, deformation and vibration of the second subframe 44 can be effectively suppressed.

[0061] Furthermore, as mentioned above, multiple second support columns 45 are arranged and, in a plan view from the direction along the second rotation axis J2, are positioned symmetrically with respect to the central axis A of the second arm 4. With this configuration, the second subframe 44 can be supported in a balanced manner, and deformation and vibration of the second subframe 44 can be effectively suppressed.

[0062] Furthermore, as mentioned above, the second arm 4 is rotatably positioned on the main frame 41 and has a shaft rotation mechanism comprising: a spline nut 61 attached to a ball screw spline shaft 63; a first motor-side pulley 912a positioned on the output shaft 911a of the first motor 911; a first shaft-side pulley 912b positioned on the spline nut 61; and a first belt 912c wrapped around the first motor-side pulley 912a and the first shaft-side pulley 912b. The robot has a shaft direct motion mechanism 92 which includes a motion mechanism 91, a ball screw nut 62 rotatably positioned on the first subframe 42 and attached to a ball screw spline shaft 63, a second motor-side pulley 922a positioned on the output shaft 921a of the second motor 921, a second shaft-side pulley 922b positioned on the ball screw nut 62, and a second belt 922c wrapped around the second motor-side pulley 922a and the second shaft-side pulley 922b. The first motor-side pulley 912a and the second motor-side pulley 922a are positioned between the main frame 41 and the first subframe 42, respectively. With this configuration, the installation positions of the first and second motors 911 and 921 are lowered. As a result, the center of gravity of the second arm 4 is kept low, and deterioration of the operational performance of the horizontal articulated robot 1 can be effectively suppressed.

[0063] <Second Embodiment> Figure 8 is a top view showing the internal structure of the second arm of the robot according to the second embodiment.

[0064] The horizontal articulated robot 1 according to this embodiment is the same as the horizontal articulated robot 1 of the first embodiment described above, except that the arrangement of each second support column 45 is different. In the following description, the horizontal articulated robot 1 of this embodiment will be described mainly in terms of the differences from the first embodiment described above, and similar matters will be omitted from the description. Also, in the figures of this embodiment, the same reference numerals are used for the same components as in the previously described embodiment.

[0065] As shown in Figure 8, in the horizontal articulated robot 1 of this embodiment, the second support column 45 is positioned within a region enclosed by a plurality of first support columns 43 in a plan view from the vertical direction. Specifically, in a plan view from the vertical direction, the first motor-side support column 451 is positioned within a triangular region S1 connecting the central axes of the central support column 431, the first end-side support column 432, and the first base-side support column 433. With this configuration, the first motor-side support column 451 is supported at three points by these three support columns 431, 432, and 433, and deformation and vibration of the first subframe 42 caused by external forces transmitted to the first subframe 42 via the first motor-side support column 451 can be effectively suppressed.

[0066] Similarly, in a plan view from the vertical, the second motor-side support column 452 is positioned within a triangular region S2 connecting the central axes of the central support column 431, the second end-side support column 434, and the second base-side support column 435. With this configuration, the second motor-side support column 452 is supported at three points by these three columns 431, 434, and 435, and deformation and vibration of the first subframe 42 caused by external forces transmitted to the first subframe 42 via the second motor-side support column 452 can be effectively suppressed. Therefore, deterioration of the operational performance of the horizontal articulated robot 1 can be effectively suppressed.

[0067] As described above, in this embodiment, the horizontal articulated robot 1 has a second support column 45 positioned within a region surrounded by multiple first support columns 43 when viewed from a vertical plane. With this configuration, deformation and vibration of the first subframe 42 caused by external forces transmitted to the first subframe 42 via the second support column 45 can be effectively suppressed. Therefore, deterioration of the operational performance of the horizontal articulated robot 1 can be effectively suppressed.

[0068] Furthermore, as mentioned above, the multiple first support columns 43 include a first end-side support column 432 located on the third rotation axis J3 side of the first motor 911 in a plan view from the direction along the second rotation axis J2, and a first base-side support column 433 located on the second rotation axis J2 side of the first motor 911. The second support column 45 is located within the region S1 enclosed by the central support column 431, the first end-side support column 432, and the first base-side support column 433. With this configuration, deformation and vibration of the first subframe 42 caused by external forces transmitted to the first subframe 42 via the second support column 45 can be effectively suppressed. Therefore, deterioration of the operating performance of the horizontal articulated robot 1 can be effectively suppressed.

[0069] Furthermore, as mentioned above, the multiple first support columns 43 include a second end-side support column 434 located on the third rotation axis J3 side of the second motor 921 in a plan view from the direction along the second rotation axis J2, and a second base-side support column 435 located on the second rotation axis J2 side of the second motor 921. The second support column 45 is located within the region S2 enclosed by the central support column 431, the second end-side support column 434, and the second base-side support column 435. With this configuration, deformation and vibration of the first subframe 42 caused by external forces transmitted to the first subframe 42 via the second support column 45 can be effectively suppressed. Therefore, deterioration of the operating performance of the horizontal articulated robot 1 can be effectively suppressed.

[0070] This second embodiment can also achieve the same effects as the first embodiment described above.

[0071] Although the horizontal articulated robot of the present invention has been described above based on the illustrated embodiment, the present invention is not limited thereto, and the configuration of each part can be replaced with any configuration having a similar function. Furthermore, any other configuration may be added to the present invention. [Explanation of symbols]

[0072] 1…Horizontal articulated robot, 10…Control device, 2…Base, 3…First arm, 4…Second arm, 41…Main frame, 42…First subframe, 421…First through hole, 422…Second through hole, 43…First support column, 431…Central support column, 432…First end-side support column, 433…First base-side support column, 434…Second end-side support column, 435…Second base-side support column, 44…Second subframe, 45…Second support column, 451…First motor-side support column 452...Second motor side support, 46...Cover, 5...Duct, 6...Work head, 61...Spline nut, 62...Ball screw nut, 63...Ball screw spline shaft, 7...First arm drive mechanism, 71...Reduction gear, 711...Circular spline, 712...Flex spline, 713...Wave generator, 72...Motor, 721...Output shaft, 8...Second arm drive mechanism, 81...Reduction gear, 811...Circular spline Curasspline, 812…Flexspline, 813…Wave generator, 82…Motor, 821…Output shaft, 9…Work head drive mechanism, 91…Shaft rotation mechanism, 911…First motor, 911a…Output shaft, 912…Transmission mechanism, 912a…First motor side pulley, 912b…First shaft side pulley, 912c…First belt, 914…First motor holding member, 92…Shaft direct motion mechanism, 921 ...Second motor, 921a...Output shaft, 922...Transmission mechanism, 922a...Second motor side pulley, 922b...Second shaft side pulley, 922c...Second belt, 923...Brake, 924...Second motor holding member, A...Center axis, B...Brake release button, C...Connector, C1...Connector, C2...Connector, J1...First rotation axis, J2...Second rotation axis, J3...Third rotation axis, O...Center, S1...Area, S2...Area

Claims

1. Base and, A first arm connected to the base and rotating around a first pivot axis relative to the base, A second arm connected to the first arm and rotating relative to the first arm around a second pivot axis, The second arm is positioned and has a shaft that rotates relative to the second arm around a third pivot axis and moves along the third pivot axis, The aforementioned second arm is connected to the main frame, A first subframe is positioned spaced apart from the main frame in a direction along the second pivot axis, A plurality of first support columns are located between the main frame and the first subframe and connect the main frame and the first subframe, A second subframe is spaced apart from the first subframe in the direction along the second pivot axis and is located on the opposite side of the main frame from the first subframe, A second support column is located between the first subframe and the second subframe and connects the first subframe and the second subframe, A first motor is positioned on the first subframe and rotates the shaft around the third pivot axis, It includes a second motor positioned on the first subframe and moving the shaft along the third pivot axis, The first motor and the second motor are arranged side by side in a direction perpendicular to the second pivot shaft, A horizontal articulated robot characterized in that the second support column is positioned between a plurality of the first support columns, or within a region enclosed by a plurality of the first support columns, in a plan view from a direction along the second pivot axis.

2. The horizontal articulated robot according to claim 1, wherein the plurality of first support columns include a central support column located between the first motor and the second motor in a plan view from a direction along the second pivot axis.

3. The plurality of first support columns include a first end support column located on the third pivot axis side of the first motor in a plan view from a direction along the second pivot axis, and a first base support column located on the second pivot axis side of the first motor. The horizontal articulated robot according to claim 2, wherein the second support column is located within the region enclosed by the central support column, the first end support column, and the first base support column.

4. The plurality of first support columns include a second end support column located on the third pivot axis side of the second motor in a plan view from a direction along the second pivot axis, and a second base support column located on the second pivot axis side of the second motor. The horizontal articulated robot according to claim 2, wherein the second support column is located within the region enclosed by the central support column, the second end support column, and the second base support column.

5. The plurality of first support columns include a first base end support column that, in a plan view from a direction along the second pivot axis, is located closer to the second pivot axis than the first motor. The horizontal articulated robot according to claim 2, wherein the second support column is located between the central support column and the first base end support column.

6. The plurality of first support columns include a second base end support column that, in a plan view from a direction along the second pivot axis, is located closer to the second pivot axis than the second motor. The horizontal articulated robot according to claim 2, wherein the second support column is located between the central support column and the second base support column.

7. The horizontal articulated robot according to claim 1, wherein the second support column is located in the center of the second subframe in the direction in which the second and third rotation axes are aligned, when viewed in a plan view from a direction along the second rotation axis.

8. The duct has a connection between the base and the second arm without passing through the first arm, and the end on the second arm side is supported by the second subframe. The horizontal articulated robot according to claim 1, wherein the second support column is arranged in a direction perpendicular to the second pivot axis and the connection portion of the duct to the second subframe in a plan view from a direction along the second pivot axis.

9. The horizontal articulated robot according to claim 1, wherein a plurality of second support columns are arranged and are symmetrically positioned with respect to the central axis of the second arm in a plan view from a direction along the second pivot axis.

10. The second arm is rotatably positioned on the main frame and comprises a shaft rotation mechanism having a spline nut mounted on the shaft, a first motor-side pulley positioned on the output shaft of the first motor, a first shaft-side pulley positioned on the spline nut, and a first belt wrapped around the first motor-side pulley and the first shaft-side pulley. The shaft linear motion mechanism includes a ball screw nut rotatably arranged on the first subframe and mounted on the shaft, a second motor-side pulley positioned on the output shaft of the second motor, a second shaft-side pulley positioned on the ball screw nut, and a second belt wrapped around the second motor-side pulley and the second shaft-side pulley. The horizontal articulated robot according to claim 1, wherein the first motor-side pulley and the second motor-side pulley are each located between the main frame and the second subframe.

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