Robot joint mechanism, robot, and method for assembling robot joint mechanism

Abstract

The present application provides a robot joint mechanism, a robot, and a method for assembling a robot joint mechanism, which can suppress a decrease in assembly accuracy. The robot joint mechanism comprises: a robot structural component having a through-hole and a first hole and a second hole arranged around the through-hole; a motor screwed and fixed using the first hole, with the output shaft of the motor inserted into the through-hole; and a wave gear device screwed and fixed using the second hole, comprising a wave generator connected to the output shaft, wherein the diameter of the through-hole is smaller than the major diameter of the wave generator.

Description

Technical Field

[0001] The invention relates to a robot joint mechanism, a robot and an assembling method of the robot joint mechanism. Background Art

[0002] Patent Document 1 describes a robot joint mechanism comprising a motor fixed to a fixed frame and a movable frame having an input connected to the motor and an output fixed to the movable frame. The wave gearing mainly comprises a wave generator, a flex spline, and a circular spline.

[0003] Such a robot joint mechanism is usually assembled through the following steps: preparing a first unit and a second unit, the first unit is formed by fixing an elastic spline and a rotating spline to a fixed frame and a movable frame, and the second unit is formed by fixing a wave generator to the output shaft of the motor; and inserting the wave generator into the elastic spline through a through hole formed in the fixed frame, and fixing the motor to the fixed frame.

[0004] Patent Document 1: International Publication No. 2018 / 055752

[0005] As described above, during assembly of the robot joint mechanism, the wave generator must be inserted through a through-hole formed in the fixing frame. Therefore, the diameter of the through-hole must be larger than the major diameter of the wave generator. Meanwhile, although the fixing frame includes a threaded hole for securing the motor, the minimum diameter of the through-hole is limited to at least the major diameter of the wave generator. Therefore, the threaded hole cannot be formed closer to the center axis of the robot joint mechanism.

[0006] Therefore, if the motor is smaller than the wave generator, securing the motor to the mounting frame becomes problematic. While it's possible to insert a relay component between the motor and mounting frame to connect them, this would increase the number of components, which would accumulate tolerances and reduce assembly precision. This would also place unintended excessive stress on the robot's joint mechanism, potentially shortening its lifespan. On the other hand, increasing component precision to reduce tolerances in order to improve assembly accuracy could result in a decrease in the yield rate and increased manufacturing costs. Summary of the Invention

[0007] The robot joint mechanism of the present invention has:

[0008] A robot structural component comprising a through hole and a first hole and a second hole arranged around the through hole;

[0009] a motor, which is screwed and fixed using the first hole, and an output shaft of the motor is inserted into the through hole; and

[0010] The wave gear device is screwed and fixed using the second hole and includes a wave generator connected to the output shaft.

[0011] The diameter of the through hole is smaller than the long diameter of the wave generator.

[0012] The robot of the present invention has:

[0013] first component;

[0014] a second component; and

[0015] A robot joint mechanism connects the first component and the second component so that the second component rotates relative to the first component.

[0016] The robot joint mechanism has:

[0017] A robot structural component comprising a through hole and a first hole and a second hole arranged around the through hole;

[0018] a motor, which is screwed and fixed using the first hole, and an output shaft of the motor is inserted into the through hole; and

[0019] The wave gear device is screwed and fixed using the second hole and includes a wave generator connected to the output shaft.

[0020] The diameter of the through hole is smaller than the long diameter of the wave generator.

[0021] The assembly method of the robot joint mechanism of the present invention includes:

[0022] A preparation step of preparing a robot structural component, wherein the robot structural component includes a through hole and a first hole and a second hole arranged around the through hole;

[0023] an inserting step of inserting the output shaft of the motor into the through hole from one side of the robot structural component;

[0024] a connecting step of connecting a wave generator as part of a wave gear device to the output shaft from the other side of the robot structural component, wherein the major diameter of the wave generator is larger than the diameter of the through hole;

[0025] a configuration step of configuring an elastic spline and a rotary spline as a part of the wave gear device from the other side of the robot structural component;

[0026] a first fixing step of screwing and fixing the wave gear device to the robot structural component using the second hole from the one side of the robot structural component; and

[0027] The second fixing step is to screw and fix the motor to the robot structural component from the one side of the robot structural component using the first hole. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a side view of the robot according to the first embodiment.

[0029] Figure 2 yes Figure 1 A cross-sectional view of a robot joint mechanism of a robot.

[0030] Figure 3 yes Figure 2 A bottom view of a flange of a robot joint mechanism.

[0031] Figure 4 This is a bottom view of the robot's joint mechanism.

[0032] Figure 5 This is a cross-sectional view of an existing robot joint mechanism.

[0033] Figure 6 This is a flowchart showing the assembly process of the robot joint mechanism.

[0034] Figure 7 This is a cross-sectional view for explaining the assembly method of the robot joint mechanism.

[0035] Figure 8 This is a cross-sectional view for explaining the assembly method of the robot joint mechanism.

[0036] Figure 9 This is a cross-sectional view for explaining the assembly method of the robot joint mechanism.

[0037] Figure 10 This is a cross-sectional view for explaining the assembly method of the robot joint mechanism.

[0038] Figure 11 This is a cross-sectional view for explaining the assembly method of the robot joint mechanism.

[0039] Figure 12 This is a cross-sectional view for explaining the assembly method of the robot joint mechanism.

[0040] Figure 13 This is a cross-sectional view for explaining the assembly method of the robot joint mechanism.

[0041] Figure 14 This is a bottom view used to explain the assembly method of the robot joint mechanism.

[0042] Figure 15 This is a bottom view used to explain the assembly method of the robot joint mechanism.

[0043] Figure 16 This is a bottom view used to explain the assembly method of the robot joint mechanism.

[0044] Figure 17 This is a bottom view used to explain the assembly method of the robot joint mechanism.

[0045] Figure 18 This is a cross-sectional view for explaining the assembly method of the robot joint mechanism.

[0046] Figure 19 It is a cross-sectional view of a robot joint mechanism according to a second embodiment.

[0047] Description of Reference Numerals

[0048] 1…Robot; 10…Relay component; 2…Base; 3…Arm; 31…First arm; 32…Second arm; 33…Work head; 331…Spline nut; 332…Ball screw nut; 333…Spline shaft; 34…End effector; 4…Robot control unit; 51…Robot joint mechanism; 51′…Robot joint mechanism; 52…Robot joint mechanism; 53…Drive unit; 54…Drive unit; 6…Motor; 61…Spindle; 63…Casing; 64…Through hole; 65…Oil seal; 67…Oil seal; 7…Wave gear unit; 71…Wave generator; 711…Wave generating portion; 712…Bearing; 73…Elastic spline; 731…Cylinder; 731a …external teeth; 732…flange; 76…rotating spline; 761…inner main bearing; 761a…threaded hole; 761b…internal teeth; 762…outer main bearing; 762a…through hole; 763…bearing; 79…cover component; 8…encoder; 81…optical scale; 82…optical sensor; 9…flange; 90…through hole; 91…first hole; 92…second hole; 93…third hole; A1…center axis; B1…first bolt; B2…second bolt; B3…third bolt; B4…fourth bolt; B5…fifth bolt; C1…virtual circle; C2…virtual circle; C3…virtual circle; J1…first rotation axis; J2…second rotation axis; J3…third rotation axis; R 71 ...long diameter; R 90 …diameter; r1…radius; r2…radius; r3…radius; S1…preparation step; S2…insertion step; S3…temporary fixing step; S4…connection step; S5…configuration step; S6…release step; S7…first fixing step; S8…second fixing step. DETAILED DESCRIPTION

[0049] Next, the robot joint mechanism, the robot, and the assembly method of the robot joint mechanism of the present invention will be described in detail according to the embodiments shown in the accompanying drawings. Figure 2 The upper side of Figure 2 For other figures, also according to Figure 2 The up and down directions specified in .

[0050] Figure 1 It is a side view of the robot according to the first embodiment. Figure 2 yes Figure 1 A cross-sectional view of a robot joint mechanism of a robot. Figure 3 yes Figure 2 A bottom view of a flange of a robot joint mechanism. Figure 4 This is a bottom view of the robot's joint mechanism. Figure 5 This is a cross-sectional view of an existing robot joint mechanism. Figure 6 This is a flowchart showing the assembly process of the robot joint mechanism. Figures 7 to 13 Each of them is a cross-sectional view for explaining the assembly method of the robot joint mechanism. Figures 14 to 17 Each of them is a bottom view for explaining the assembly method of the robot joint mechanism. Figure 18 This is a cross-sectional view for explaining the assembly method of the robot joint mechanism. Figure 2 It is along Figure 3 Cross-sectional view along line AA.

[0051] Figure 1 The robot 1 shown is a horizontal multi-joint robot (SCARA robot) used for various operations such as holding, conveying, assembling, and inspecting workpieces such as electronic components. However, the structure and application of the robot 1 are not particularly limited.

[0052] The robot 1 has a base 2 fixed to the ground and an arm 3 connected to the base 2. The arm 3 includes a first arm 31, whose base end is connected to the base 2 and rotates relative to the base 2 about a first rotation axis J1 extending in the vertical direction; and a second arm 32, whose base end is connected to the front end of the first arm 31 and rotates relative to the first arm 31 about a second rotation axis J2 extending in the vertical direction. The first rotation axis J1 and the second rotation axis J2 are parallel.

[0053] A working head 33 is provided at the front end of the second arm 32. The working head 33 comprises a spline nut 331 and a ball screw nut 332 coaxially arranged at the front end of the second arm 32, and a spline shaft 333 inserted through the spline nut 331 and the ball screw nut 332. The spline shaft 333 is rotatable relative to the second arm 32 about its central axis, a third rotation axis J3 extending vertically, and is also capable of being raised and lowered along the third rotation axis J3. The third rotation axis J3 is parallel to the first rotation axis J1 and the second rotation axis J2.

[0054] An end effector 34 is mounted on the lower end of the spline shaft 333. The end effector 34 is selected to be easily attachable and detachable and suitable for the intended task. Examples of the end effector 34 include a hand that grips or holds a workpiece by suction, a work tool that performs a predetermined process on the workpiece, and the like.

[0055] The robot 1 further includes a robot joint mechanism 51 that connects the base 2 and the first arm 31 and rotates the first arm 31 relative to the base 2 about the first rotation axis J1; and a robot joint mechanism 52 that connects the first arm 31 and the second arm 32 and rotates the second arm 32 relative to the first arm 31 about the second rotation axis J2. The robot 1 further includes a drive device 53 that rotates the spline nut 331 to rotate the spline shaft 333 about the third rotation axis J3; and a drive device 54 that rotates the ball screw nut 332 to raise and lower the spline shaft 333 in a direction along the third rotation axis J3.

[0056] The robot 1 also includes a robot control device 4, which is located within the base 2 and controls the driving of the robot joint mechanisms 51 and 52 and the drive devices 53 and 54 in response to commands from a host computer (not shown). The robot control device 4 independently controls the robot joint mechanisms 51 and 52 and the drive devices 53 and 54, thereby enabling the robot 1 to perform a desired operation.

[0057] The robot control device 4 is comprised of, for example, a computer and includes a processor for processing information, a memory communicatively connected to the processor, and an external interface. The memory stores various programs executable by the processor, and the processor can read and execute the various programs stored in the memory.

[0058] The above briefly describes the overall structure of robot 1. Next, the robot joint mechanisms 51 and 52 included in robot 1 will be described in detail. Since robot joint mechanisms 51 and 52 are identical except for their different configurations, the following will focus on robot joint mechanism 51 in detail, while the description of robot joint mechanism 52 will be omitted.

[0059] like Figure 2 As shown, the robot joint mechanism 51 includes a flange 9, a motor 6 disposed on the lower surface of the flange 9, an encoder 8 disposed on the lower side of the motor 6, and a wave gear device 7 disposed on the upper surface of the flange 9. The rotation axis of the main shaft 61 of the motor 6 is referred to as the center axis A1 of the robot joint mechanism 51. This center axis A1 constitutes the first rotation axis J1 of the robot 1.

[0060] Flange 9

[0061] The flange 9 is a robot structural component that constitutes part of the robot 1. It supports the motor 6 and the wave gear device 7 and secures the robot joint mechanism 51 to the base 2. Specifically, the motor 6 and the wave gear device 7 are secured to the base 2 via the flange 9. However, the robot structural component is not limited to the flange 9; for example, the base 2 may also be used. In other words, in this embodiment, the motor 6 and the wave gear device 7 are secured to the base 2 via the flange 9. However, this is not limiting; the motor 6 and the wave gear device 7 may also be secured directly to the base 2. This reduces the number of components in the robot 1. Furthermore, this reduction in the number of components eliminates the need for screw fastening, improving rigidity. Furthermore, it reduces assembly man-hours.

[0062] like Figure 2 As shown, a through hole 90 is formed in the center of the flange 9, and the main shaft 61 of the motor 6 is inserted into the through hole 90 from the bottom. The through hole 90 is generally circular with the central axis A1 as the center. However, the shape of the through hole 90 is not particularly limited.

[0063] Furthermore, the diameter R of the through hole 90 is 90 smaller than the major diameter R of the wave generator 71 included in the wave gear device 7 71 That is, R 90 <R 71 . In other words, when viewed from above in the direction along the center axis A1, the through hole 90 overlaps with the wave generator 71. Therefore, as shown in the figure, even if the motor 6 is smaller than the wave gear device 7, it can be fixed to the flange 9 without going through a relay component as in the existing one. Therefore, it is possible to suppress the reduction in the accuracy of mounting the motor 6 on the flange 9, and effectively suppress the deviation of the center axis A1. In addition, since there is no relay component, the tolerances of the flange 9 and the housing 63 can be set loosely accordingly, which can suppress the reduction in the qualified product rate and also achieve a reduction in manufacturing costs. In addition, this effect will be described in detail later.

[0064] And, as Figure 2 As shown, flange 9 is formed with: a first hole 91 for securing motor 6 to the lower surface of flange 9; a second hole 92 for securing wave gear device 7 to the upper surface of flange 9; and a third hole 93 for securing flange 9 to base 2, serving as the first component. First hole 91 is a threaded hole (female thread) for threading a first bolt B1, while second hole 92 and third hole 93 are through-holes for inserting second bolt B2 and third bolt B3, respectively, extending through the upper and lower surfaces.

[0065] like Figure 3As shown, four first holes 91 are arranged at approximately equal intervals along a virtual circle C1 with a radius r1 centered on the central axis A1, so as to surround the through-hole 90. Furthermore, sixteen second holes 92 are arranged at approximately equal intervals along a virtual circle C2 with a radius r2 centered on the central axis A1, so as to surround the through-hole 90. Furthermore, six third holes 93 are arranged at approximately equal intervals along a virtual circle C3 with a radius r3 centered on the central axis A1, so as to surround the through-hole 90.

[0066] By arranging the plurality of first holes 91 along the virtual circle C1, the motor 6 can be securely fixed to the flange 9 in a well-balanced manner. Similarly, by arranging the plurality of second holes 92 along the virtual circle C2, the wave gear device 7 can be securely fixed to the flange 9 in a well-balanced manner. This improves the mechanical strength of the robot joint mechanism 51, thereby preventing degradation in the life of the robot joint mechanism 51. Furthermore, by arranging the plurality of third holes 93 along the virtual circle C3, the robot joint mechanism 51 can be securely fixed to the base 2 in a well-balanced manner, thereby improving the mechanical strength of the robot 1.

[0067] The three concentrically arranged virtual circles C1, C2, and C3 have the relationship of radius r1 < radius r2 < radius r3. That is, the second hole 92 is located closer to the center axis A1 than the third hole 93, and the first hole 91 is located closer to the center axis A1 than the second hole 92. This placement of the first hole 91 closer to the center axis A1 than the second hole 92 allows the motor 6, which is smaller than the wave gear device 7, to be more securely fixed to the flange 9 without intervening intermediate components.

[0068] Motor 6

[0069] like Figure 2 As shown, the motor 6 is disposed below the flange 9. The motor 6 is, for example, an AC servo motor. However, the motor 6 is not particularly limited; for example, a DC servo motor or a stepping motor may also be used. The motor 6 includes a main shaft 61 serving as an output shaft, a stator (not shown) that rotates the main shaft 61, and a housing 63 that houses these components.

[0070] Four insertion holes 64 are formed at the upper end of the housing 63 for screwing the motor 6 to the flange 9. Each insertion hole 64 overlaps with the first hole 91, and a first bolt B1 is inserted from below into each insertion hole 64. This first bolt B1 is then screwed into the first hole 91 of the flange 9. This secures the motor 6 to the flange 9. However, the number of first holes 91 and corresponding insertion holes 64 is not particularly limited. Furthermore, the number of first holes 91 and insertion holes 64 may not be the same.

[0071] Here, when the motor 6 is fixed to the flange 9, Figure 4 As shown, at least one (eight in the illustrated configuration) second hole 92 overlaps with the motor 6. With this configuration, the robot joint mechanism 51 can be assembled according to the assembly method described below. Therefore, there is no need to worry about the second hole 92 overlapping the motor 6, increasing the design freedom of the robot joint mechanism 51. As a result, the robot joint mechanism 51 is capable of being used with motors 6 of various sizes, improving its versatility.

[0072] And, as Figure 2 As shown, the main shaft 61 is supported by a housing 63 so as to be rotatable about a central axis A1. Furthermore, the main shaft 61 is connected to the wave gear device 7 at its upper end and to the encoder 8 at its lower end. Thus, the rotation of the main shaft 61 is transmitted to both the wave gear device 7 and the encoder 8.

[0073] Furthermore, housing 63 has a convex portion on its upper side, which engages with the side wall of through-hole 90 in flange 9. Furthermore, an oil seal 67 is disposed between housing 63 and flange 9, and an oil seal 65 is disposed in the gap between main shaft 61 and housing 63. These oil seals 65 and 67 suppress oil leakage from wave gear device 7.

[0074] Encoder 8

[0075] like Figure 2 As shown, the encoder 8 is arranged along the first rotation axis J1 and arranged below the motor 6. The encoder 8 includes an optical scale 81 fixed to the spindle 61 and an optical sensor 82 for detecting the rotation state of the optical scale 81.

[0076] The optical scale 81 rotates around the first rotation axis J1 together with the main shaft 61. In addition, a detection pattern (not shown) capable of detecting the rotation angle of the optical scale 81 is formed on the lower surface of the optical scale 81. On the other hand, the optical sensor 82 has a light-emitting element that emits light toward the detection pattern on the optical scale 81 and a light-receiving element that receives light reflected from the detection pattern. In the encoder 8 of this structure, as the optical scale 81 rotates around the first rotation axis J1, the waveform of the output signal from the light-receiving element changes. Therefore, the rotation angle of the main shaft 61 can be detected based on the output signal.

[0077] Wave gear device 7

[0078] like Figure 2 As shown, the wave gear device 7 is arranged on the upper surface side of the flange 9. The wave gear device 7 is arranged along the first rotation axis J1 and is located above the motor 6. This wave gear device 7 reduces the rotation of the main shaft 61 at a high reduction ratio and outputs it, thereby generating a high torque proportional to the reduction ratio.

[0079] The wave gear device 7 includes a wave generator 71, elastic splines 73, rotating splines 76, and a cover member 79. In the wave gear device 7, the wave generator 71 is an input side for the power input to the motor 6, and the rotating splines 76 is an output side for reducing the power of the motor 6 and outputting it.

[0080] The rotating spline 76 is an annular internally toothed gear formed of a substantially inflexible rigid body. It includes an inner main bearing 761 and an outer main bearing 762 located outside the inner main bearing 761. The inner and outer main bearings 761 and 762 are connected by a bearing 763, allowing relative rotation between the outer and inner main bearings 762 and 761.

[0081] The inner circumference of the inner main bearing 761 is formed with internal teeth 761b that mesh with the elastic splines 73. Furthermore, 16 threaded holes 761a are formed on the lower surface of the inner main bearing 761. Each threaded hole 761a overlaps with a second hole 92. A second bolt B2 is inserted from below into each second hole 92 and then screwed into the threaded hole 761a. This secures the wave gear device 7 to the flange 9. However, the number of second holes 92 and the corresponding threaded holes 761a is not particularly limited. Furthermore, the number of second holes 92 and threaded holes 761a does not need to be the same.

[0082] As described above, the motor 6 and the wave gear device 7 are secured to the flange 9 by first and second bolts B1 and B2, both of which are inserted from the bottom. Inserting the first and second bolts B1 and B2 from the same side facilitates assembly and disassembly of the robot joint mechanism 51. However, this is not limiting; the first and second bolts B1 and B2 may also be inserted from different sides.

[0083] Meanwhile, the outer main bearing 762 has insertion holes 762a extending through its upper and lower surfaces. Fourth bolts B4 are inserted from below into each insertion hole 762a and then screwed into the cover member 79. This secures the outer main bearing 762 and the cover member 79. Furthermore, the cover member 79 is secured to the first arm 31, serving as the second member, via fifth bolts B5. However, the method for securing the outer main bearing 762 to the first arm 31 is not particularly limited. For example, the cover member 79 may be omitted and secured directly to the first arm 31.

[0084] The elastic spline 73 is arranged inside the rotating spline 76. The elastic spline 73 includes a cylindrical portion 731 having flexibility to bend and deform along the outer circumference of the wave generator 71, and an annular flange portion 732 connected to the upper end of the cylindrical portion 731.

[0085] The outer periphery of the cylindrical portion 731 is formed with external teeth 731a that mesh with the internal teeth 761b of the rotating spline 76. The number of teeth of the external teeth 731a is set smaller than the number of teeth of the internal teeth 761b. The flange portion 732 is fixed to the cover member 79 together with the outer main bearing 762 by fourth bolts B4.

[0086] Furthermore, the wave generator 71 includes: a wave generating portion 711 fixed to the main shaft 61 and rotating in conjunction with the rotation of the main shaft 61; and a bearing 712 embedded between the wave generating portion 711 and the elastic spline 73. When viewed from above in the direction along the center axis A1, the outer periphery of the wave generating portion 711 is elliptical or oblong. That is, the wave generator 71 is in a shape having a long side direction and a short side direction orthogonal to the long side direction. The wave generator 71 contacts the inner peripheral surface of the cylindrical portion 731 of the elastic spline 73, causing the cylindrical portion 731 to bend into an elliptical or oblong shape so that the outer teeth 731a of the cylindrical portion 731 partially engage with the inner teeth 761b of the rotating spline 76. As a result, the teeth at the portion of the long axis are engaged with the rotating spline 76 and the teeth at the portion of the short axis are completely disengaged. In addition, the length of the long axis of the wave generator 71 is the major diameter R 71 As mentioned above, the major diameter R 71 Greater than the diameter R of the through hole 90 90 .

[0087] When the wave generator 71 receives driving force from the motor 6, the meshing positions of the elastic spline 73 and the rotating spline 76 sequentially shift circumferentially, causing relative rotation about the central axis A1 due to the difference in the number of teeth. In this embodiment, the elastic spline 73 and the outer main bearing 762 are fixed to the first arm 31 via the cover member 79, while the inner main bearing 761 is fixed to the base 2 via the flange 9. This allows the first arm 31 to rotate relative to the base 2 about the first rotation axis J1.

[0088] According to the wave gear device 7 , the rotation input from the motor 6 to the wave generator 71 is decelerated and then output from the outer main bearing of the rotating spline 76 , thereby obtaining a torque proportional to the reduction ratio on the output side.

[0089] The structure of the robot joint mechanism 51 has been described above. As mentioned above, the robot joint mechanism 51 has R 90 <R 71 By having such a relationship, a space is generated inside the flange 9 relative to the second hole 92, and the first hole 91 can be formed in the space. That is, the first hole 91 for fixing the motor 6 can be arranged inside the second hole 92 for fixing the wave gear device 7. Therefore, even if the motor 6 is smaller in size (diameter) than the wave gear device 7, it can be fixed to the flange 9 without a relay component. In addition, for reference, Figure 5 In the90 >R 71 The structure in which the motor 6 is fixed to the flange 9 via the relay component 10 is shown as a robot joint mechanism 51 ′.

[0090] This improves the precision with which the motor 6 is mounted on the flange 9, effectively preventing misalignment between the rotation axis of the main shaft 61 and the rotation axis of the wave gear device 7. This stabilizes the driving of the robot joint mechanism 51 and reduces the risk of unintended excessive stress on the robot joint mechanism 51. Consequently, a reduction in the lifespan of the robot joint mechanism 51 can be effectively minimized. Furthermore, since no intermediate components are involved, the number of components is reduced, allowing for looser tolerances between the flange 9 and the housing 63, minimizing any reduction in yield and reducing manufacturing costs.

[0091] The following describes the assembly method of the robot joint mechanism 51. Figure 6 As shown, the assembly method of the robot joint mechanism 51 includes the following steps: a preparation step S1 for preparing the flange 9; an insertion step S2 for inserting the main shaft 61 of the motor 6 into the through hole 90 of the flange 9; a temporary fixing step S3 for temporarily securing the motor 6 to the flange 9; a connection step S4 for connecting the wave generator 71 to the main shaft 61; a configuration step S5 for arranging the elastic spline 73 and the rotating spline 76; a release step S6 for releasing the temporary fixation of the motor 6; a first fixing step S7 for fixing the wave gear device 7 to the flange 9; and a second fixing step S8 for fixing the motor 6 to the flange 9. Each of these steps S1 to S8 will be described below in sequence.

[0092] Preparation step S1

[0093] First, if Figure 7 As shown in FIG. 1 , a flange 9 is prepared. The flange 9 is formed with a through hole 90 , a first hole 91 , a second hole 92 , and a third hole 93 .

[0094] Insertion step S2

[0095] Then, if Figure 8 As shown in FIG. 1 , the motor 6 is prepared, and the main shaft 61 of the motor 6 is inserted from the lower side into the through hole 90 of the flange 9. As a result, the main shaft 61 protrudes upward from the through hole 90.

[0096] Temporary fixing step S3

[0097] Then, if Figure 9 As shown, the motor 6 is temporarily secured to the flange 9 using the first bolt B1. In this step, the first bolt B1 is tightened with a sufficient force to prevent the motor 6 from vibrating relative to the flange 9. Eliminating any looseness between the motor 6 and the flange 9 allows the subsequent connection step S4 and placement step S5 to be performed smoothly and accurately.

[0098] Connection step S4

[0099] Then, if Figure 10 As shown, the wave generator 71 is connected and fixed to the main shaft 61 from the upper surface side of the flange 9. In this way, after the main shaft 61 is inserted into the through hole 90, the wave generator 71 is connected to the main shaft 61 from the opposite side. 71 Even with a small through hole 90 , the robot joint mechanism 51 can be easily assembled.

[0100] Configuration step S5

[0101] Then, if Figure 11 As shown, the elastic spline 73 and the rotating spline 76 are arranged from the upper surface side of the flange 9, and the wave gear device 7 is assembled.

[0102] Release step S6

[0103] Then, if Figure 12 As shown, the first bolts B1 securing the motor 6 to the flange 9 are removed, releasing the temporary fixation of the motor 6. Even after the temporary fixation is released, the main shaft 61 is supported by the wave gear device 7, preventing the motor 6 from detaching. Furthermore, with the temporary fixation released, the housing 63 is freely rotatable about the central axis A1. This allows for the successful execution of the first fixing step S7.

[0104] First fixing step S7

[0105] Then, if Figure 13 As shown, the second bolts B2 are inserted through the second holes 92 and screwed into the threaded holes 761 a of the inner main bearing 761 .

[0106] The following is a detailed description. First, the housing 63 is rotated relative to the flange 9 around the central axis A1. Figure 14 The status shown. Figure 14 , 8 second holes 92 overlap with the shell 63, and the remaining 8 second holes 92 do not overlap with the shell 63. Then, as Figure 15 As shown, the second bolts B2 are inserted through the second holes 92 that do not overlap with the housing 63 and screwed into the threaded holes 761 a of the inner main bearing 761 .

[0107] Then, if Figure 16 As shown, the housing 63 is rotated 45° relative to the flange 9 around the central axis A1. Figure 14 The second hole 92 that overlaps with the housing 63 does not overlap with the housing 63. Figure 14The second hole 92 that does not overlap with the housing 63 overlaps with the housing 63. Figure 17 As shown, the second bolts B2 are inserted through the second holes 92 that do not overlap with the housing 63 and screwed into the threaded holes 761 a of the inner main bearing 761 .

[0108] As a result, the second bolts B2 are inserted through all the second holes 92, securing the wave gear device 7 to the flange 9. Specifically, the wave gear device 7 is screwed and secured to the flange 9 using the second holes 92 that overlap with the motor 6. This allows the wave gear device 7 to be securely and well-balancedly secured to the flange 9 around the through-holes 90. Consequently, the mechanical strength of the robot joint mechanism 51 is improved, and a reduction in the life of the robot joint mechanism 51 can be suppressed. Furthermore, according to this method, all second holes 92 can be sequentially positioned so that they no longer overlap with the housing 63 simply by rotating the housing 63. This reduces the need to worry about overlap between the second holes 92 and the motor 6, and improves the design flexibility of the robot joint mechanism 51. As a result, a robot joint mechanism 51 is adaptable to motors 6 of various sizes, improving its versatility.

[0109] Second fixing step S8

[0110] Then, if Figure 18 As shown, the first bolts B1 are inserted into the insertion holes 64 of the housing 63 from the bottom side, and the first bolts B1 are screwed into the first holes 91 of the flange 9 , thereby fixing the motor 6 to the flange 9 .

[0111] The assembly of the robot joint mechanism 51 is completed through the above. According to such an assembly method, even if the motor 6 is smaller in size (diameter) than the wave gear device 7, it can be fixed to the flange 9 without a relay component. Therefore, the accuracy of mounting the motor 6 on the flange 9 is improved, and the deviation of the rotation axis of the main shaft 61 and the rotation axis of the wave gear device 7 can be effectively suppressed. Therefore, the drive of the robot joint mechanism 51 is stable, and it is not easy to apply excessive stress unexpectedly to the robot joint mechanism 51. As a result, the reduction in the service life of the robot joint mechanism 51 can be effectively suppressed. On the other hand, since there is no relay component, the number of components is reduced accordingly, and the tolerances of the flange 9 and the housing 63 can be set loosely, which can suppress the reduction in the qualified product rate and achieve a reduction in manufacturing costs.

[0112] Furthermore, the order of steps S1 to S8 in the assembly method described above is not limited; other orders are possible. For example, the order of the placement step S5 and subsequent steps can be changed, with a portion of the first securing step S7 performed before the release step S6. Specifically, the second bolts B2 can be inserted through the eight second holes 92 that do not overlap with the housing 63 and then screwed into the threaded holes 761a of the inner main bearing 761. This allows for stable assembly of the flange 9 and the wave gear device 7.

[0113] The above describes the assembly method of the robot 1, the robot joint mechanism 51, and the robot joint mechanism 52. As described above, the robot joint mechanism 51 comprises: a flange 9 as a robot structural component, having a through hole 90 and a first hole 91 and a second hole 92 arranged around the through hole 90; a motor 6, which is screwed and fixed using the first hole 91, and a main shaft 61 as an output shaft is inserted into the through hole 90; and a wave gear device 7, which is screwed and fixed using the second hole 92, and has a wave generator 71 connected to the main shaft 61, and the diameter R of the through hole 90 is 1 / 4. 90 Smaller than the long diameter R of the wave generator 71 71 .

[0114] Thus, by having R 90 <R 71 In this relationship, a space is created inside the flange 9 relative to the second hole 92, and the first hole 91 can be formed in this space. That is, the first hole 91 for fixing the motor 6 can be arranged inside the second hole 92 for fixing the wave gear device 7. Therefore, even if the motor 6 is smaller in size (diameter) than the wave gear device 7, it is not necessary to pass through the second hole 92. Figure 5 The relay component 10 shown can be fixed to the flange 9. Therefore, the accuracy of mounting the motor 6 on the flange 9 is improved, and the deviation of the rotation axis of the main shaft 61 and the rotation axis of the wave gear device 7 can be effectively suppressed. Therefore, the drive of the robot joint mechanism 51 is stable, and it is not easy to apply excessive stress unexpectedly to the robot joint mechanism 51. As a result, the reduction in the service life of the robot joint mechanism 51 can be effectively suppressed. On the other hand, since the relay component 10 is not used, the number of parts is reduced accordingly, and the tolerances of the flange 9 and the housing 63 can be set loosely, which can suppress the reduction in the yield rate and reduce the manufacturing cost.

[0115] Furthermore, as described above, the motor 6 and the wave gear device 7 are screwed and fixed to the flange 9 from the same side. This facilitates assembly and disassembly of the robot joint mechanism 51.

[0116] Furthermore, as described above, a plurality of second holes 92 are arranged along the periphery of the through-hole 90. This allows the wave gear device 7 to be securely fixed to the flange 9 around the through-hole 90 in a well-balanced manner. Consequently, the mechanical strength of the robot joint mechanism 51 is improved, and a reduction in the life of the robot joint mechanism 51 can be suppressed.

[0117] Furthermore, as described above, when viewed from above along the central axis A1 of the main shaft 61, at least one second hole 92 overlaps with the motor 6. The wave gear device 7 is screwed and fixed to the flange 9 using the second hole 92 that overlaps with the motor 6. This allows the wave gear device 7 to be securely fixed to the flange 9 around the through-hole 90 in a well-balanced manner. Consequently, the mechanical strength of the robot joint mechanism 51 is improved, and a reduction in the life of the robot joint mechanism 51 can be suppressed.

[0118] As described above, the first hole 91 is located closer to the through hole than the second hole 92. Thus, the motor 6, which is smaller than the wave gear device 7, can be more reliably fixed to the flange 9 without the intermediate member 10.

[0119] As described above, the robot 1 includes: a base 2 as a first component; a first arm 31 as a second component; and a robot joint mechanism 51 that connects the base 2 and the first arm 31 and rotates the first arm 31 relative to the base 2. Furthermore, the robot joint mechanism 51 includes: a flange 9 as a robot structural component, which includes a through-hole 90 and a first hole 91 and a second hole 92 arranged around the through-hole 90; a motor 6 that is screwed and fixed using the first hole 91, and a main shaft 61 as an output shaft is inserted into the through-hole 90; and a wave gear device 7 that is screwed and fixed using the second hole 92 and includes a wave generator 71 connected to the main shaft 61, and a diameter R of the through-hole 90. 90 Smaller than the long diameter R of the wave generator 71 71 Thus, the robot 1 can achieve the effects of the robot joint mechanism 51 described above and has excellent reliability.

[0120] Furthermore, as mentioned above, the robot component can also be the base 2. That is, by securing the motor 6 and the wave gear device 7 to the base 2 without the flange 9, the number of components can be reduced. Furthermore, this reduction in the number of components eliminates the need for screw fastening, improving rigidity and reducing assembly man-hours.

[0121] As described above, the assembly method of the robot joint mechanism 51 includes: a preparation step S1, in which a flange 9 as a structural member of the robot is prepared, wherein the flange 9 has a through hole 90 and a first hole and a second hole arranged around the through hole 90; an insertion step S2, in which a main shaft 61 as an output shaft of the motor 6 is inserted into the through hole 90 from one side of the flange 9, i.e., the lower side; and a connection step S4, in which a long diameter R 1 as a part of the wave gear device 7 is connected to the flange 9 from the other side, i.e., the upper side. 71 Greater than the diameter R of the through hole 90 90 The wave generator 71 is connected to the main shaft 61; a configuration step S5, configuring the elastic spline 73 and the rotating spline 76 as part of the wave gear device 7 from the upper side of the flange 9; a first fixing step S7, screwing the wave gear device 7 to the flange 9 using the second hole 92 from the lower side of the flange 9; and a second fixing step S8, screwing the motor 6 to the flange 9 using the first hole 91 from the lower surface side of the flange 9.

[0122] Thus, by having R 90 <R 71 In this relationship, a space is created inside the flange 9 relative to the second hole 92, and the first hole 91 can be formed in this space. That is, the first hole 91 for fixing the motor 6 can be arranged inside the second hole 92 for fixing the wave gear device 7. Therefore, even if the motor 6 is smaller in size (diameter) than the wave gear device 7, it is not necessary to pass through the second hole 92. Figure 5 The relay component 10 shown can be fixed to the flange 9. Therefore, the accuracy of mounting the motor 6 on the flange 9 is improved, and the deviation of the rotation axis of the main shaft 61 and the rotation axis of the wave gear device 7 can be effectively suppressed. Therefore, the drive of the robot joint mechanism 51 is stable, and it is not easy to apply excessive stress unexpectedly to the robot joint mechanism 51. As a result, the reduction in the service life of the robot joint mechanism 51 can be effectively suppressed. On the other hand, since the relay component 10 is not used, the number of parts is reduced accordingly, and the tolerances of the flange 9 and the housing 63 can be set loosely, which can suppress the reduction in the yield rate and reduce the manufacturing cost.

[0123] Furthermore, as described above, the assembly method of the robot joint mechanism 51 includes: a temporary fixing step S3, performed between the insertion step S2 and the connection step S4, to temporarily fix the motor 6 to the flange 9; and a release step S6, performed between the placement step S5 and the first fixing step S7, to release the temporary fixation of the motor 6. This allows the steps following the temporary fixing step S3 to be performed smoothly.

[0124] Furthermore, as described above, multiple second holes 92 are formed around the through-hole 90. When the placement step S5 is completed, at least one second hole 92 overlaps with the motor 6 when viewed from above along the central axis A1 of the main shaft 61. In the first fixing step S7, the motor 6 is rotated about the central axis A1 to release the overlap, and the wave gear device 7 is screwed and fixed to the flange 9 using all of the second holes 92. This allows the wave gear device 7 to be securely and well-balanced around the through-hole 90 relative to the flange 9. Consequently, the mechanical strength of the robot joint mechanism 51 is improved, and a reduction in the life of the robot joint mechanism 51 can be suppressed.

[0125] Second embodiment

[0126] Figure 19 It is a cross-sectional view of a robot joint mechanism according to a second embodiment.

[0127] The robot joint mechanism 51 of this embodiment is identical to the robot joint mechanism 51 of the first embodiment described above, except for the placement of the oil seal 65. Therefore, the following description of this embodiment will focus on the differences from the first embodiment, and descriptions of identical matters will be omitted. Furthermore, in the drawings of this embodiment, identical components to those of the aforementioned embodiment are denoted by the same reference numerals.

[0128] like Figure 19 As shown, in the robot joint mechanism 51 of this embodiment, the diameter R of the through hole 90 is larger than that of the first embodiment. 90 The inner surface of the through hole 90 is smaller, and its inner surface is closer to the outer circumferential surface of the main shaft 61. Furthermore, the oil seal 65, which prevents oil leakage from the wave gear device 7, is located in the gap between the housing 63 and the main shaft 61 in the first embodiment. In this embodiment, it is located between the inner circumferential surface of the through hole 90 and the outer circumferential surface of the main shaft 61. This configuration allows, for example, the oil seal 67 to be omitted, further simplifying the structure of the robot joint mechanism 51. Furthermore, the number of components is reduced, thereby lowering manufacturing costs.

[0129] Thus, the robot joint mechanism 51 of this embodiment includes the oil seal 65 disposed between the inner circumferential surface of the through-hole 90 and the outer circumferential surface of the spindle 61. This further simplifies the structure of the robot joint mechanism 51 and reduces the number of components, thereby lowering manufacturing costs.

[0130] According to the second embodiment as described above, the same effects as those of the first embodiment can be achieved.

[0131] While the robot joint mechanism, robot, and method for assembling the robot joint mechanism of the present invention have been described above based on the illustrated embodiments, the present invention is not limited thereto. The structures of the various components can be replaced with any other components having the same function. Furthermore, any additional components may be added to the present invention.

Claims

1. A robot joint mechanism, characterized in that: have: A robot structural component comprising a through hole and a first hole and a second hole arranged around the through hole; a motor, screwed and fixed to the robot structural component using the first hole, and an output shaft of the motor is inserted into the through hole; as well as The wave gear device comprises: a wave generator connected to the output shaft, wherein the outer periphery of the wave generator is elliptical when viewed from above along the output shaft; an elastic spline capable of bending and deforming along the outer periphery of the wave generator and having external teeth; and a rotating spline having internal teeth meshing with the external teeth and rotating relative to the elastic spline. The rotary spline is screwed and fixed to the robot structural component using the second hole, The diameter of the through hole is smaller than the long diameter of the wave generator.

2. The robot joint mechanism according to claim 1, characterized in that: The motor and the wave gear device are screwed and fixed to the robot structural component from the same side.

3. The robot joint mechanism according to claim 1 or 2, characterized in that: A plurality of the second holes are arranged along the periphery of the through hole.

4. The robot joint mechanism according to claim 3, characterized in that: When viewed from above along the central axis of the output shaft, at least one of the second holes overlaps with the motor, The wave gear device is screwed and fixed to the robot structural component using the second hole overlapping with the motor.

5. The robot joint mechanism according to claim 1 or 2, characterized in that: The robot joint mechanism includes an oil seal disposed between an inner peripheral surface of the through hole and an outer peripheral surface of the output shaft.

6. The robot joint mechanism according to claim 1 or 2, characterized in that: The first hole is located closer to the through hole than the second hole.

7. A robot, characterized in that: have: first component; Second component; as well as A robot joint mechanism connects the first component and the second component so that the second component rotates relative to the first component. The robot joint mechanism has: A robot structural component comprising a through hole and a first hole and a second hole arranged around the through hole; a motor, screwed and fixed to the robot structural component using the first hole, and an output shaft of the motor is inserted into the through hole; as well as The wave gear device comprises: a wave generator connected to the output shaft, wherein the outer periphery of the wave generator is elliptical when viewed from above along the output shaft; an elastic spline capable of bending and deforming along the outer periphery of the wave generator and having external teeth; and a rotating spline having internal teeth meshing with the external teeth and rotating relative to the elastic spline. The rotary spline is screwed and fixed to the robot structural component using the second hole, The diameter of the through hole is smaller than the long diameter of the wave generator.

8. The robot according to claim 7, characterized in that The robot structural component is the first component.

9. A method for assembling a robot joint mechanism, characterized in that: The robot joint mechanism has: A robot structural component comprising a through hole and a first hole and a second hole arranged around the through hole; a motor, screwed and fixed to the robot structural component using the first hole, and an output shaft of the motor is inserted into the through hole; as well as A wave gear device comprising: a wave generator connected to the output shaft, wherein the outer periphery of the wave generator is elliptical when viewed from above along the output shaft; and an elastic spline capable of flexing and deforming along the outer periphery of the wave generator and having external teeth. and a rotating spline having internal teeth meshing with the external teeth and rotating relative to the elastic spline, The assembly method of the robot joint mechanism includes: A preparation step, preparing the robot structural components; an inserting step of inserting the output shaft of the motor into the through hole from one side of the robot structural component; a connecting step of connecting the wave generator to the output shaft from the other side of the robot structural component, wherein the major diameter of the wave generator is greater than the diameter of the through hole; a configuration step of configuring the elastic spline and the rotary spline from the other side of the robot structural component; a first fixing step of screwing and fixing the rotary spline to the robot structural component using the second hole from the one side of the robot structural component; and The second fixing step is to screw and fix the motor to the robot structural component from the one side of the robot structural component using the first hole.

10. The method for assembling a robot joint mechanism according to claim 9, wherein: The assembly method of the robot joint mechanism includes: a temporary fixing step, performed between the inserting step and the connecting step, of temporarily fixing the motor to the robot structural component; The releasing step is performed between the arranging step and the first fixing step, and releases the temporary fixing of the motor.

11. The method for assembling a robot joint mechanism according to claim 9 or 10, characterized in that: A plurality of second holes are formed around the through hole. In a state where the arrangement step is completed, at least one of the second holes overlaps with the motor when viewed from above along the central axis of the output shaft. In the first fixing step, the motor is rotated about the central axis to release the overlap with the motor, and the wave gear device is screwed and fixed to the robot structural component using all of the second holes.

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