CN115805609A

CN115805609A - Robot joint mechanism, robot, and method for assembling robot joint mechanism

Info

Publication number: CN115805609A
Application number: CN202211102968.6A
Authority: CN
Inventors: 下岛聪兴
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2021-09-13
Filing date: 2022-09-09
Publication date: 2023-03-17
Also published as: JP2023041450A

Abstract

The application provides a robot joint mechanism, a robot and an assembling method of the robot joint mechanism, which can restrain the reduction of assembling precision. The robot joint mechanism includes: a robot structural member including 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, an output shaft of the motor being inserted into the through hole; and a wave gear device screwed and fixed by using the second hole, and including 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

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

Technical Field

The present invention relates to a robot joint mechanism, a robot, and a method of assembling the robot joint mechanism.

Background

Patent document 1 describes a robot joint mechanism including: a motor fixed on the fixed frame; and the input side is connected with the motor and the output side is fixed on the movable frame. Also, the wave gear device mainly has a wave generator, a flexible spline (flex spline), and a rotary spline (circular spline).

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

Patent document 1: international publication No. 2018/055752

As described above, in assembling the robot joint mechanism, the wave generator needs to be inserted into the through hole formed in the fixing frame, and therefore, the diameter of the through hole needs to be larger than the major diameter of the wave generator. On the other hand, although the fixing frame is formed with a screw hole for fixing the motor, the minimum diameter of the through hole is limited to the longer diameter of the wave generator or more, and therefore the screw hole cannot be formed closer to the central axis of the robot joint mechanism than this.

Therefore, for example, in the case where the motor is small relative to the wave generator, fixing the motor to the fixed frame becomes a problem. For example, although a method of interposing a relay member for connecting the motor and the fixed frame may be considered, the number of members increases, and accordingly, the tolerance is accumulated to lower the assembly accuracy, and an excessive stress other than the expected stress is applied to the robot joint mechanism, which may reduce the life of the robot joint mechanism. On the other hand, if the component accuracy is increased to reduce the tolerance in order to improve the assembly accuracy, the yield may be reduced, and the manufacturing cost may be increased.

Disclosure of Invention

The robot joint mechanism of the present invention includes:

a robot structural member including 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, an output shaft of the motor being inserted into the through hole; and

a wave gear device screwed and fixed by using the second hole, and including a wave generator connected to the output shaft,

the diameter of the through hole is smaller than the major diameter of the wave generator.

The robot of the present invention comprises:

a first member;

a second component; and

a robot joint mechanism connecting the first member and the second member to rotate the second member relative to the first member,

the robot joint mechanism includes:

The method for assembling a robot joint mechanism according to the present invention includes:

a preparation step of preparing a robot structural member including a through hole and a first hole and a second hole arranged around the through hole;

an insertion step of inserting an output shaft of a motor into the through hole from one side of the robot structural member;

a connection step of connecting a wave generator as a part of a wave gear device to the output shaft from the other side of the robot structural member, the wave generator having a longer diameter larger than the diameter of the through hole;

a disposing step of disposing an elastic spline and a rotational spline that are a part of the wave gear device from the other side of the robot structural member;

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

a second fixing step of screwing and fixing the motor to the robot structural member using the first hole from the one side of the robot structural member.

Drawings

Fig. 1 is a side view of a robot according to a first embodiment.

Fig. 2 is a sectional view of a robot joint mechanism included in the robot of fig. 1.

Fig. 3 is a bottom view of a flange provided in the robot joint mechanism of fig. 2.

Fig. 4 is a bottom view of the robot joint mechanism.

Fig. 5 is a sectional view of a conventional robot joint mechanism.

Fig. 6 is a flowchart showing an assembly process of the robot joint mechanism.

Fig. 7 is a sectional view for explaining an assembling method of the robot joint mechanism.

Fig. 8 is a sectional view for explaining an assembling method of the robot joint mechanism.

Fig. 9 is a sectional view for explaining an assembling method of the robot joint mechanism.

Fig. 10 is a sectional view for explaining an assembling method of the robot joint mechanism.

Fig. 11 is a sectional view for explaining an assembling method of the robot joint mechanism.

Fig. 12 is a sectional view for explaining an assembling method of the robot joint mechanism.

Fig. 13 is a sectional view for explaining an assembling method of the robot joint mechanism.

Fig. 14 is a bottom view for explaining an assembling method of the robot joint mechanism.

Fig. 15 is a bottom view for explaining an assembling method of the robot joint mechanism.

Fig. 16 is a bottom view for explaining an assembling method of the robot joint mechanism.

Fig. 17 is a bottom view for explaining an assembling method of the robot joint mechanism.

Fig. 18 is a sectional view for explaining an assembling method of the robot joint mechanism.

Fig. 19 is a sectional view of a robot joint mechanism according to the second embodiment.

Description of the reference numerals

1 … robot; 10 … relay component; 2 … base; 3 … arm; 31 …; a 32 … second arm; 33 … work head; 331 … spline nut; 332 … ball screw nut; 333 … splined shaft; 34 … end effector; 4 … robot control device; 51 … robot joint mechanism; 51' … robot joint mechanism; 52 … robot joint mechanism; 53 … drive; 54 … drive; a 6 … motor; 61 … spindle; 63 … shell; 64 … through holes; 65 … oil seal; 67 … oil seal; 7 … wave gear device; 71 … wave generator; 711 … fluctuation generating part; 712 … bearings; 73 … elastic spline; 731 … cylindrical portion; 731a … outer teeth; 732 … flange portion; 76 …;761 … an inner main bearing; 761a … threaded hole; 761b … internal teeth; 762 … outboard main bearing; 762a … through hole; 763 … bearing; 79 … hood part; an 8 … encoder; 81 … optical scale; 82 … optical sensor; 9 … flange; 90 … through holes; 91 … first aperture; 92 …;93 … third aperture; a1 … central axis; b1 … first bolt; a B2 … second bolt; b3 …; b4 … fourth bolt; b5 …; c1 … virtual circle; c2 … virtual circle; c3 … virtual circle; a first rotating shaft J1 …; a second axis of rotation J2 …; a third rotating shaft J3 …; r ₇₁ … long diameter; r ₉₀ … diameter; r1 … radius; r2 … radius; r3 … radius; s1 … preparation step; s2 … inserting step; s3 … temporarily fixing; s4 …; s5 … configuration step; s6 … removing step; s7 … a first fixing step; s8 … second fixing step.

Detailed Description

The robot joint mechanism, the robot, and the method of assembling the robot joint mechanism according to the present invention will be described in detail below with reference to the embodiments shown in the drawings. For convenience of explanation, the upper side of fig. 2 is referred to as the upper side, and the lower side of fig. 2 is referred to as the lower side. For the other figures, the vertical direction is also defined in fig. 2.

Fig. 1 is a side view of a robot according to a first embodiment. Fig. 2 is a sectional view of a robot joint mechanism included in the robot of fig. 1. Fig. 3 is a bottom view of a flange provided in the robot joint mechanism of fig. 2. Fig. 4 is a bottom view of the robot joint mechanism. Fig. 5 is a sectional view of a conventional robot joint mechanism. Fig. 6 is a flowchart showing an assembly process of the robot joint mechanism. Fig. 7 to 13 are sectional views for explaining a method of assembling the robot joint mechanism. Fig. 14 to 17 are bottom views for explaining a method of assembling the robot joint mechanism. Fig. 18 is a sectional view for explaining an assembling method of the robot joint mechanism. In addition, fig. 2 isbase:Sub>A sectional view taken along linebase:Sub>A-base:Sub>A in fig. 3.

The Robot 1 shown in fig. 1 is a horizontal articulated Robot (SCARA Robot), and is used for various operations such as holding, transporting, assembling, and inspecting workpieces such as electronic components. However, the structure and the use of the robot 1 are not particularly limited.

The robot 1 includes a base 2 fixed to the floor and an arm 3 connected to the base 2. The arm 3 has: a first arm 31 having a base end connected to the base 2 and rotatable with respect to the base 2 about a first rotation axis J1 along the vertical direction; the second arm 32 has a base end connected to the tip end of the first arm 31, and pivots with respect to the first arm 31 about a second pivot axis J2 along the vertical direction. The first rotation axis J1 and the second rotation axis J2 are parallel.

A working head 33 is provided at the tip end of the second arm 32. The working head 33 includes: a spline nut 331 and a ball screw nut 332 coaxially disposed at the distal end portion 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 about the third pivot axis J3 whose center axis is along the vertical direction with respect to the second arm 32, and is also movable up and down along the third pivot axis J3. The third pivot axis J3 is parallel to the first pivot axis J1 and the second pivot axis J2.

An end effector 34 is attached to the lower end of the spline shaft 333. The end effector 34 is appropriately selected from end effectors that are freely attachable and detachable and suitable for the target operation. Examples of the end effector 34 include a hand holding a workpiece by clamping or suction, and a work tool performing a predetermined process on a workpiece.

The robot 1 further includes: a robot joint mechanism 51 that couples the base 2 and the first arm 31 and rotates the first arm 31 relative to the base 2 about a first rotation axis J1; and a robot joint mechanism 52 that couples 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 spline nut 331 to rotate spline shaft 333 about third rotation axis J3; and a driving device 54 that rotates the ball screw nut 332 and raises and lowers the spline shaft 333 in the direction along the third rotation axis J3.

The robot 1 includes a robot control device 4, and the robot control device 4 is disposed in the base 2 and controls the driving of the robot

joint mechanisms

51 and 52 and the

driving devices

53 and 54 in accordance with a command from a host computer, not shown. The robot controller 4 can cause the robot 1 to perform a desired operation by independently controlling the robot

joint mechanisms

51 and 52 and the

driving devices

53 and 54, respectively.

The robot control device 4 is constituted by, for example, a computer, and includes: a processor for processing information; a memory communicatively connected with the processor; and an external interface. Various programs that can be executed by the processor are stored in the memory, and the processor can read and execute the various programs stored in the memory.

The overall structure of the robot 1 is briefly described above. Next, the robot

joint mechanisms

51 and 52 provided in the robot 1 will be described in detail. Since the robot

joint mechanisms

51 and 52 have the same configuration except for different arrangements, the robot joint mechanism 51 will be described in detail below, and the robot joint mechanism 52 will not be described.

As shown in fig. 2, the robot joint mechanism 51 includes: a flange 9; a motor 6 disposed on the lower surface side of the flange 9; an encoder 8 disposed below the motor 6; and a wave gear device 7 disposed on the upper surface side of the flange 9. In the following description, the rotation axis of the spindle 61 included in the motor 6 is defined as the central axis A1 of the robot joint mechanism 51. The central axis A1 constitutes a first rotation axis J1 of the robot 1.

Flange 9

The flange 9 is a robot structural member constituting a part of the robot 1, and is a member that supports the motor 6 and the wave gear device 7 and fixes the robot joint mechanism 51 to the base 2. That is, the motor 6 and the wave gear device 7 are fixed to the base 2 via the flange 9. However, the robot structural member is not limited to the flange 9, and may be, for example, the base 2. That is, although the motor 6 and the wave gear device 7 are fixed to the base 2 via the flange 9 in the present embodiment, the present invention is not limited thereto, and the motor 6 and the wave gear device 7 may be directly fixed to the base 2. This can reduce the number of components of the robot 1. Further, since the number of parts is reduced, fastening of screws is not required, and rigidity can be improved. Further, the number of assembly steps can be reduced.

As shown in fig. 2, a through hole 90 is formed in the center of the flange 9, and the spindle 61 of the motor 6 is inserted into the through hole 90 from below. The through hole 90 is substantially circular about the central axis A1. However, the shape of the through-hole 90 is not particularly limited.

And, the diameter R of the through hole 90 ₉₀ Smaller than the major diameter R of the wave generator 71 of the wave gear device 7 ₇₁ . Namely, R ₉₀ <R ₇₁ . In other words, the through-hole 90 overlaps the wave generator 71 when viewed in a plan view from a direction along the central axis A1. Thus, as shown in the drawing, even the motor 6 having a size smaller than that of the wave gear device 7 can be fixed to the flange 9 without passing through a conventional relay member. Therefore, a decrease in accuracy of mounting the motor 6 to the flange 9 can be suppressed, and the deviation of the central axis A1 can be effectively suppressed. Further, since no relay member is interposed, the tolerances of the flange 9 and the housing 63 can be set to be relaxed accordingly, and a reduction in the yield and a reduction in the manufacturing cost can be achieved. This effect will be described in detail later.

As shown in fig. 2, the flange 9 has: a first hole 91 for fixing the motor 6 to the lower surface of the flange 9; a second hole 92 for fixing the wave gear device 7 to the upper surface of the flange 9; and a third hole 93 for fixing the flange 9 to the base 2 as the first member. The first hole 91 is a threaded hole (female thread) into which the first bolt B1 is screwed, and the second hole 92 and the third hole 93 are through holes through which the second bolt B2 and the third bolt B3 are inserted and which penetrate the upper and lower surfaces.

As shown in fig. 3, the first holes 91 are arranged at substantially equal intervals along a virtual circle C1 having a radius r1 around the central axis A1 so as to surround the periphery of the through hole 90. Further, 16 second holes 92 are arranged at substantially equal intervals along a virtual circle C2 of a radius r2 centered on the central axis A1 so as to surround the periphery of the through hole 90. The number of the third holes 93 is 6 at substantially equal intervals along a virtual circle C3 having a radius r3 around the central axis A1 so as to surround the periphery of the through hole 90.

By arranging the plurality of first holes 91 along the virtual circle C1 in this way, the motor 6 can be fixed firmly to the flange 9 with good balance. Similarly, by disposing the plurality of second holes 92 along the virtual circle C2, the wave gear device 7 can be firmly fixed to the flange 9 with good balance. Therefore, the mechanical strength of the robot joint mechanism 51 is improved, and the reduction in the life of the robot joint mechanism 51 can be suppressed. Further, since the robot joint mechanism 51 can be firmly fixed to the base 2 with good balance by arranging the plurality of third holes 93 along the virtual circle C3, the mechanical strength of the robot 1 is improved.

The 3 virtual circles C1, C2, and C3 concentrically arranged are in the relationship of radius r1< radius r2< radius r 3. That is, the second hole 92 is positioned closer to the central axis A1 side than the third hole 93, and the first hole 91 is positioned closer to the central axis A1 side than the second hole 92. By disposing the first hole 91 closer to the central axis A1 than the second hole 92 in this way, the motor 6 having a size smaller than that of the wave gear device 7 can be more reliably fixed to the flange 9 without the need of a relay member.

Electric machine 6

As shown in fig. 2, the motor 6 is disposed below the flange 9. The motor 6 is, for example, an AC servomotor. However, the motor 6 is not particularly limited, and for example, a DC servo motor, a stepping motor, or the like may be used. The motor 6 includes a main shaft 61 as an output shaft, a stator, not shown, for rotating the main shaft 61, and a housing 63 for housing the stator and the stator.

At the upper end of the housing 63, 4 insertion holes 64 for screwing and fixing the motor 6 to the flange 9 are formed. The insertion holes 64 overlap the first holes 91, the first bolts B1 are inserted into the insertion holes 64 from below, and the first bolts B1 are screwed into the first holes 91 of the flange 9. Thereby, the motor 6 is fixed to the flange 9. However, the number of the first holes 91 and the corresponding insertion holes 64 is not particularly limited. The number of the first holes 91 and the number of the insertion holes 64 may be different from each other.

Here, in a state where the motor 6 is fixed to the flange 9, as shown in fig. 4, at least one (8 in the illustrated structure) second hole 92 overlaps the motor 6. In such a configuration, the robot joint mechanism 51 can be assembled according to an assembly method described later. Therefore, there is no need to consider the overlap of the second hole 92 and the motor 6, and the degree of freedom in designing the robot joint mechanism 51 is improved. As a result, the robot joint mechanism 51 is formed to be able to apply motors 6 of various sizes, and the versatility thereof is improved.

As shown in fig. 2, the main shaft 61 is supported by the housing 63 so as to be rotatable about the center axis A1. The main shaft 61 is coupled to the wave gear device 7 at its upper end portion and to the encoder 8 at its lower end portion. Thereby, the rotation of the main shaft 61 is transmitted to the wave gear device 7 and the encoder 8, respectively.

The housing 63 has a projection on the upper side, and the projection of the housing 63 engages with the side wall of the through hole 90 of the flange 9. An oil seal 67 is disposed between the housing 63 and the flange 9, and an oil seal 65 is disposed in a gap between the main shaft 61 and the housing 63. Oil leakage from the wave gear device 7 is suppressed by these oil seals 65, 67.

Encoder 8

As shown in fig. 2, the encoder 8 is arranged along the first rotation axis J1 with the motor 6 and is located below the motor 6. The encoder 8 includes an optical scale 81 fixed to the spindle 61 and an optical sensor 82 that detects a rotation state of the optical scale 81.

The optical scale 81 rotates together with the spindle 61 about the first rotation axis J1. 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 includes 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 by the detection pattern. In the encoder 8 having such a configuration, the waveform of the output signal from the light receiving element changes as the optical scale 81 rotates about the first rotation axis J1. Therefore, the rotation angle of the spindle 61 can be detected from the output signal.

Wave gear device 7

As shown in fig. 2, the wave gear device 7 is disposed on the upper surface side of the flange 9. The wave gear device 7 is arranged along the first rotation axis J1 with the motor 6 and is located above the motor 6. Such a wave gear device 7 reduces the speed of rotation of the main shaft 61 at a high reduction ratio and outputs the reduced rotation, thereby generating high torque proportional to the reduction ratio.

The wave gear device 7 has a wave generator 71, an elastic spline 73, a rotary spline 76, and a cover member 79. In the wave gear device 7, the wave generator 71 serves as an input side to which power of the motor 6 is input, and the rotational spline 76 serves as an output side to which the power of the motor 6 is reduced and output.

The rotary spline 76 is an annular internal gear made of a rigid body that does not substantially flex. The rotary spline 76 has an inner main bearing 761 and an outer main bearing 762 located outside the inner main bearing 761. Further, inner main bearing 761 and outer main bearing 762 are coupled to each other by a bearing 763, and outer main bearing 762 and inner main bearing 761 are relatively rotatable.

An inner tooth 761b that engages with the elastic spline 73 is formed on the inner periphery of the inner main bearing 761. Further, 16 screw holes 761a are formed in the lower surface of the inner main bearing 761. The screw holes 761a overlap the second holes 92, the second bolts B2 are inserted into the second holes 92 from below, and the second bolts B2 are screwed into the screw holes 761a. Thereby, the wave gear device 7 is fixed to the flange 9. However, the number of the second holes 92 and the corresponding screw holes 761a is not particularly limited. The number of the second holes 92 and the number of the screw holes 761a may not be the same.

As described above, the motor 6 and the wave gear device 7 are fixed to the flange 9 by the first bolt B1 and the second bolt B2, both of which are inserted from below. By inserting the first bolt B1 and the second bolt B2 from the same side in this manner, the robot joint mechanism 51 can be easily assembled and disassembled. However, the present invention is not limited to this, and the first bolt B1 and the second bolt B2 may be inserted from different sides.

On the other hand, an insertion hole 762a penetrating the upper and lower surfaces is formed in the outer main bearing 762. The fourth bolts B4 are inserted into the insertion holes 762a from below, and the fourth bolts B4 are screwed and inserted into the cover member 79. Thereby fixing outer main bearing 762 and shroud member 79. The cover member 79 is fixed to the first arm 31 as the second member by a fifth bolt B5. However, a method of fixing outer main bearing 762 and first arm 31 is not particularly limited. For example, the cover member 79 may be omitted and fixed directly to the first arm 31.

The elastic spline 73 is disposed inside the rotational spline 76. The elastic spline 73 has: a cylindrical portion 731 having flexibility capable of flexural deformation along the outer periphery of the wave generator 71; and an annular flange portion 732 connected to an upper end portion of the cylindrical portion 731.

Outer teeth 731a that mesh with inner teeth 761b of rotary spline 76 are formed on the outer peripheral portion of cylindrical portion 731. The number of teeth of external teeth 731a is set to be smaller than that of internal teeth 761b. The flange portion 732 is fixed to the cover member 79 together with the outer main bearing 762 by the fourth bolt B4.

The wave generator 71 further includes: a wave generating unit 711 fixed to the main shaft 61 and rotating in conjunction with the rotation of the main shaft 61; and a bearing 712 fitted between the wave generating portion 711 and the elastic spline 73. The wave generating portion 711 has an elliptical or oval outer periphery when viewed in plan from a direction along the center axis A1. That is, the wave generator 71 has a shape having a longitudinal direction and a short-side direction orthogonal to the longitudinal direction. The wave generator 71 contacts the inner peripheral surface of the cylindrical portion 731 of the elastic spline 73 to deflect the cylindrical portion 731 into an elliptical shape or an elliptical shapeIn an oblong shape, external teeth 731a of cylindrical portion 731 partially meshes with internal teeth 761b of rotary spline 76. This brings about a state in which the teeth mesh with the rotational spline 76 at the portion of the major axis and the teeth are completely disengaged at the portion of the minor axis. The length of the major axis of the wave generator 71 is the major axis R ₇₁ As described above, the major axis R ₇₁ Is larger than the diameter R of the through hole 90 ₉₀ 。

When the driving force from the motor 6 is input to the wave generator 71, the positions where the elastic spline 73 and the rotational spline 76 are engaged with each other move sequentially in the circumferential direction, and rotate relative to each other around the central axis A1 due to the difference in the number of teeth. In the present embodiment, since the elastic spline 73 and the outer main bearing 762 are fixed to the first arm 31 via the cover member 79 and the inner main bearing 761 is fixed to the base 2 via the flange 9, the first arm 31 rotates relative to the base 2 about the first rotation axis J1.

According to the wave gear device 7, the rotation input from the motor 6 to the wave generator 71 is reduced in speed and then output from the outer main bearing of the rotational spline 76, and a torque proportional to the reduction ratio can be obtained on the output side.

The structure of the robot joint mechanism 51 has been described above. As described above, the robot joint mechanism 51 has R ₉₀ <R ₇₁ The relationship (2) of (c). By having such a relationship, a space is created inside the second hole 92 of the flange 9, and the first hole 91 can be formed in the space. That is, the first hole 91 for fixing the motor 6 can be disposed 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 member. In addition, for reference, in fig. 5, R is represented ₉₀ ＞R ₇₁ And a structure in which the motor 6 is fixed to the flange 9 via the relay member 10 is shown as a robot joint mechanism 51'.

Therefore, the accuracy of mounting the motor 6 to the flange 9 is improved, and the deviation of the rotation axis of the main shaft 61 from the rotation axis of the wave gear device 7 can be effectively suppressed. Therefore, the robot joint mechanism 51 is stably driven, and excessive stress other than intended is not easily applied to the robot joint mechanism 51. As a result, the reduction in the life of the robot joint mechanism 51 can be effectively suppressed. On the other hand, since no relay member is interposed, the number of parts is reduced accordingly, and the tolerances of the flange 9 and the housing 63 can be set loosely, so that the reduction of the yield can be suppressed, and the reduction of the manufacturing cost can be realized.

The following describes a method of assembling the robot joint mechanism 51. As shown in fig. 6, the method of assembling the robot joint mechanism 51 includes the steps of: a preparation step S1 of preparing the flange 9; an insertion step S2 of inserting the spindle 61 of the motor 6 into the through hole 90 of the flange 9; a temporary fixing step S3 of temporarily fixing the motor 6 to the flange 9; a connection step S4 of connecting the wave generator 71 to the main shaft 61; a disposing step S5 of disposing the elastic spline 73 and the rotational spline 76; a release step S6 for releasing the temporary fixation of the motor 6; a first fixing step S7 of fixing the wave gear device 7 to the flange 9; and a second fixing step S8 of fixing the motor 6 to the flange 9. These steps S1 to S8 will be described in order.

Preparation step S1

First, as shown in fig. 7, the 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.

Plug-through step S2

Next, as shown in fig. 8, the motor 6 is prepared, and the spindle 61 of the motor 6 is inserted into the through hole 90 of the flange 9 from the lower portion Fang Cecha. Thereby, the main shaft 61 protrudes upward from the through hole 90.

Temporary fixing step S3

Then, as shown in fig. 9, the motor 6 is temporarily fixed to the flange 9 using the first bolt B1. In this step, the first bolt B1 is tightened with a tightening force to such an extent that the motor 6 does not shake with respect to the flange 9. By eliminating the rattling of the motor 6 and the flange 9, the following connection step S4 and the placement step S5 can be smoothly and accurately performed.

Connection step S4

Then, as shown in fig. 10, the wave generator 71 is connected and fixed to the main shaft 61 from the upper surface side of the flange 9. Thus, after the spindle 61 is inserted into the through hole 90,the wave generator 71 is connected to the main shaft 61 from the opposite side, thereby having a diameter larger than the major diameter R of the wave generator 71 ₇₁ The small through hole 90 also allows easy assembly of the robot joint mechanism 51.

Configuration step S5

Then, as shown in fig. 11, the wave gear device 7 is assembled by disposing the elastic spline 73 and the rotational spline 76 from the upper surface side of the flange 9.

Release step S6

Then, as shown in fig. 12, the first bolt B1 for fixing the motor 6 to the flange 9 is removed, and the temporary fixing of the motor 6 is released. Even if the temporary fixation is released, the main shaft 61 is supported by the wave gear device 7, so that the disengagement of the motor 6 is prevented. In the state where the temporary fixation is released, the housing 63 is in a state of being rotatable around the central axis A1. This enables the first fixing step S7 to be performed satisfactorily.

First fixing step S7

Then, as shown in fig. 13, second bolts B2 are inserted into the second holes 92 and screwed into the screw holes 761a of the inner main bearing 761. Thereby, the wave gear device 7 is fixed to the flange 9.

To be more specific, first, the housing 63 is rotated about the central axis A1 with respect to the flange 9, and the state shown in fig. 14 is obtained. In fig. 14, 8 second holes 92 overlap the housing 63, and the remaining 8 housings 63 do not overlap the housing 63. Then, as shown in fig. 15, second bolts B2 are inserted into the second holes 92 that do not overlap the housing 63, and are screwed into the screw holes 761a of the inner main bearing 761.

Then, as shown in fig. 16, the housing 63 is rotated by 45 ° about the center axis A1 with respect to the flange 9. In this state, the second hole 92 that overlaps the housing 63 in the state of fig. 14 does not overlap the housing 63, and conversely, the second hole 92 that does not overlap the housing 63 in the state of fig. 14 overlaps the housing 63. Then, as shown in fig. 17, second bolts B2 are inserted into the second holes 92 that do not overlap the housing 63, and are screwed into the screw holes 761a of the inner main bearing 761.

As a result, the second bolts B2 are inserted through all of the second holes 92, and the wave gear device 7 is fixed to the flange 9. That is, the wave gear device 7 is screwed and fixed to the flange 9 using the second hole 92 overlapping the motor 6. This enables the wave gear device 7 to be firmly fixed around the through hole 90 with good balance with respect to the flange 9. Therefore, the mechanical strength of the robot joint mechanism 51 is improved, and the reduction in the life of the robot joint mechanism 51 can be suppressed. Further, according to this method, since all the second holes 92 are not overlapped with the housing 63 in order by rotating the housing 63, the necessity of overlapping the second holes 92 with the motor 6 is reduced, and the degree of freedom in designing the robot joint mechanism 51 is improved. As a result, the robot joint mechanism 51 is formed to be able to apply motors 6 of various sizes, and versatility thereof is improved.

Second fixing step S8

Then, as shown in fig. 18, the first bolts B1 are inserted into the respective insertion holes 64 of the housing 63 from below, and the first bolts B1 are screwed and inserted into the first holes 91 of the flange 9, thereby fixing the motor 6 to the flange 9.

The assembly of the robot joint mechanism 51 is completed in this way. According to this 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 using a relay member. Therefore, the accuracy of mounting the motor 6 to the flange 9 is improved, and the deviation of the rotation axis of the main shaft 61 from the rotation axis of the wave gear device 7 can be effectively suppressed. Therefore, the robot joint mechanism 51 is stably driven, and excessive stress other than intended is not easily applied to the robot joint mechanism 51. As a result, the reduction in the life of the robot joint mechanism 51 can be effectively suppressed. On the other hand, since no relay member is interposed, the number of parts is reduced accordingly, and the tolerances of the flange 9 and the housing 63 can be set loosely, so that the reduction of the yield can be suppressed, and the reduction of the manufacturing cost can be realized.

The order of steps S1 to S8 in the above-described assembly method is not limited, and other orders may be used. For example, the order of the configuration step S5 and thereafter may be changed, and a part of the first fixing step S7 may be executed before the release step S6. That is, the second bolts B2 may be inserted into the 8 second holes 92 that do not overlap the housing 63 and screwed into the screw holes 761a of the inner main bearing 761. In this way, the flange 9 and the wave gear device 7 can be stably assembled.

The robot 1, the robot joint mechanism 51, and the method of assembling the robot joint mechanism 52 have been described above. As described above, the robot joint mechanism 51 includes: the flange 9 as a robot structural member includes a through hole 90, and a first hole 91 and a second hole 92 disposed around the through hole 90; a motor 6 screwed and fixed by using a 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 screwed and fixed by using a second hole 92, and including a wave generator 71 connected to the main shaft 61, the diameter R of the through hole 90 ₉₀ Smaller than the major diameter R of the wave generator 71 ₇₁ 。

Thus, by having R ₉₀ <R ₇₁ In relation to (3), a space is formed inside the second hole 92 of the flange 9, and the first hole 91 can be formed in the space. That is, the first hole 91 for fixing the motor 6 can be disposed 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 the intermediary of the relay member 10 as shown in fig. 5. Therefore, the accuracy of mounting the motor 6 to the flange 9 is improved, and the misalignment between the rotation axis of the main shaft 61 and the rotation axis of the wave gear device 7 can be effectively suppressed. Therefore, the robot joint mechanism 51 is stably driven, and excessive stress other than intended is not easily applied to the robot joint mechanism 51. As a result, the reduction in the life of the robot joint mechanism 51 can be effectively suppressed. On the other hand, since the relay member 10 is not interposed, the number of parts is reduced accordingly, and the tolerances of the flange 9 and the housing 63 can be set loosely, so that the reduction of the yield can be suppressed, and the reduction of the manufacturing cost can be realized.

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.

As described above, the second holes 92 are arranged in plural numbers along the periphery of the through-hole 90. This enables the wave gear device 7 to be firmly fixed around the through hole 90 with good balance with respect to the flange 9. Therefore, the mechanical strength of the robot joint mechanism 51 is improved, and the reduction in the life of the robot joint mechanism 51 can be suppressed.

As described above, when viewed in plan from the direction along the central axis A1 of the main shaft 61, at least one second hole 92 overlaps the motor 6, and the wave gear device 7 is screwed and fixed to the flange 9 using the second hole 92 overlapping the motor 6. This enables the wave gear device 7 to be firmly fixed around the through hole 90 with good balance with respect to the flange 9. Therefore, the mechanical strength of the robot joint mechanism 51 is improved, and the reduction in the life of the robot joint mechanism 51 can be suppressed.

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 in size than the wave gear device 7, can be more reliably fixed to the flange 9 without the need of the relay member 10.

As described above, the robot 1 includes: a base 2 as a first member; a first arm 31 as a second member; and a robot joint mechanism 51 that connects the base 2 and the first arm 31 and rotates the first arm 31 with respect to the base 2. The robot joint mechanism 51 further includes: the flange 9 as a robot structural member includes a through hole 90, and a first hole 91 and a second hole 92 disposed around the through hole 90; a motor 6 screwed and fixed by using a 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 screwed and fixed by using a second hole 92, and including a wave generator 71 connected to the main shaft 61, the diameter R of the through hole 90 ₉₀ Smaller than the major diameter R of the wave generator 71 ₇₁ . This makes it possible to achieve the effects of the robot joint mechanism 51 described above and to form the robot 1 having excellent reliability.

As described above, the robot structural member may be the base 2. That is, the number of components can be reduced by fixing the motor 6 and the wave gear device 7 to the base 2 without the flange 9. Further, since the number of parts is reduced, fastening of screws is not required, and rigidity can be improved. Further, the number of assembly steps can be reduced.

As described above, the method of assembling the robot joint mechanism 51 includes: a preparation step S1 of preparing a flange 9 as a robot structural member, the flange 9 including a through hole 90 and first and second holes arranged around the through hole 90; an insertion step S2 of inserting the spindle 61, which is the output shaft of the motor 6, into the through hole 90 from one side, i.e., the lower side, of the flange 9; a connection step S4 of connecting the other side of the flange 9, i.e., the upper side, with the major axis R as a part of the wave gear device 7 ₇₁ Is larger than the diameter R of the through hole 90 ₉₀ Is connected to the main shaft 61; a disposing step S5 of disposing the elastic spline 73 and the rotational spline 76, which are part of the wave gear device 7, from above the flange 9; a first fixing step S7 of screwing and fixing 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 of screwing and fixing the motor 6 to the flange 9 using the first hole 91 from the lower surface side of the flange 9.

Thus, by having R ₉₀ <R ₇₁ In relation to (3), a space is formed inside the second hole 92 of the flange 9, and the first hole 91 can be formed in the space. That is, the first hole 91 for fixing the motor 6 can be disposed 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 the intermediary of the relay member 10 as shown in fig. 5. Therefore, the accuracy of mounting the motor 6 to the flange 9 is improved, and the deviation of the rotation axis of the main shaft 61 from the rotation axis of the wave gear device 7 can be effectively suppressed. Therefore, the robot joint mechanism 51 is stably driven, and excessive stress other than intended is not easily applied to the robot joint mechanism 51. As a result, the reduction in the life of the robot joint mechanism 51 can be effectively suppressed. On the other hand, since the relay member 10 is not interposed, the number of parts is reduced, and the tolerances of the flange 9 and the housing 63 can be set to be relaxed, so that the reduction of the yield can be suppressed, and the reduction of the manufacturing cost can be realized。

As described above, the method of assembling the robot joint mechanism 51 includes: a temporary fixing step S3, performed between the insertion step S2 and the connection step S4, of temporarily fixing the motor 6 to the flange 9; a release step S6, which is performed between the arrangement step S5 and the first fixing step S7, to release the temporary fixing of the motor 6. This enables the steps after the provisional fixing step S3 to be performed satisfactorily.

As described above, the plurality of second holes 92 are formed along the periphery of the through hole 90, and in the state where the disposing step S5 is completed, at least one second hole 92 overlaps the motor 6 when viewed in plan from the direction along the central axis A1 of the main shaft 61, and in the first fixing step S7, the motor 6 is rotated about the central axis A1 to release the overlap with the motor 6, and the wave gear device 7 is screwed and fixed to the flange 9 using all the second holes 92. This enables the wave gear device 7 to be firmly fixed around the through hole 90 with good balance with respect to the flange 9. Therefore, the mechanical strength of the robot joint mechanism 51 is improved, and the reduction in the life of the robot joint mechanism 51 can be suppressed.

Second embodiment

The robot joint mechanism 51 of the present embodiment is the same as the robot joint mechanism 51 of the first embodiment described above, except for the arrangement of the oil seal 65. Therefore, in the following description, the present embodiment will be mainly described focusing on differences from the first embodiment described above, and descriptions of the same items will be omitted. In the drawings of the present embodiment, the same components as those of the above-described embodiment are denoted by the same reference numerals.

As shown in fig. 19, in the robot joint mechanism 51 of the present embodiment, the diameter R of the through hole 90 is larger than that of the first embodiment described above ₉₀ And smaller, the inner surface thereof approaches the outer peripheral surface of the main shaft 61. In the first embodiment, the oil seal 65 for suppressing oil leakage from the wave gear device 7 is disposed in the gap between the housing 63 and the main shaft 61In the present embodiment, the through hole 90 is disposed between the inner peripheral surface and the outer peripheral surface of the spindle 61. With such a configuration, for example, the oil seal 67 can be omitted, and the structure of the robot joint mechanism 51 can be simplified. Further, the number of parts is reduced, and manufacturing cost can be reduced.

As described above, the robot joint mechanism 51 of the present embodiment includes the oil seal 65 disposed between the inner peripheral surface of the through hole 90 and the outer peripheral surface of the main shaft 61. This makes the structure of the robot joint mechanism 51 simpler. Further, the number of parts is reduced, and manufacturing cost can be reduced.

According to the second embodiment as described above, the same effects as those of the first embodiment can be obtained.

The robot joint mechanism, the robot, and the method of assembling the robot joint mechanism according to the present invention have been described above with reference to the illustrated embodiments, but the present invention is not limited thereto, and the configuration of each part may be replaced with any component having the same function. Further, any component may be added to the present invention.

Claims

1. A robot joint mechanism is characterized by comprising:

2. The robot joint mechanism according to claim 1,

the motor and the wave gear device are screwed and fixed to the robot structural member from the same side.

3. The robot joint mechanism according to claim 1 or 2,

the second hole is provided in plurality along the periphery of the through hole.

4. The robot joint mechanism according to claim 3,

when viewed from above in a direction along the central axis of the output shaft,

at least one of the second apertures overlaps the motor,

the wave gear device is screwed and fixed to the robot structural member using the second hole overlapping with the motor.

5. The robot joint mechanism according to claim 1 or 2,

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,

the first hole is located closer to the through hole than the second hole.

7. A robot, comprising:

a first member;

a second component; and

the robot joint mechanism includes:

8. The robot of claim 7,

the robot structural component is the first component.

9. A method of assembling a robot joint mechanism, comprising:

a second fixing step of screwing and fixing the motor to the robot structural member from the one side of the robot structural member using the first hole.

10. The method of assembling a robot joint mechanism according to claim 9,

the assembling method of the robot joint mechanism comprises the following steps:

a temporary fixing step of temporarily fixing the motor to the robot structural member, the temporary fixing step being performed between the inserting step and the connecting step;

a releasing step of releasing the temporary fixation of the motor, performed between the disposing step and the first fixing step.

11. The method of assembling a robot joint mechanism according to claim 9 or 10,

the second hole is formed in plurality along the periphery of the through hole,

at least one of the second holes overlaps the motor when viewed in a plan view from a direction along a central axis of the output shaft in a state where the arranging step is finished,

in the first fixing step, the motor is rotated around the central axis to release the overlapping with the motor, and the wave gear device is screwed and fixed to the robot structural member using all of the second holes.