Robot

Abstract

The present invention provides a robot which can sufficiently ensure rigidity even when a motor is disposed eccentrically with respect to a speed reducer. The robot includes one or more rotary joints (1), and each rotary joint (1) includes: a motor (2); a speed reducer (3) that decelerates the rotation of the motor (2); and a first member (5) and a second member (4). The first member (5) and the second member (4) are connected by the speed reducer (3) and are supported so as to be rotatable about the central axis (A1) of the speed reducer (3). On the first member (5) of at least one rotary joint (1), a flange fixing portion (9) for fixing a flange (8) of the motor (2) is provided at a position eccentric with respect to the central axis (A1) of the speed reducer (3), and bolts (15) for fixing the first member (5) to the speed reducer (3) are also disposed within a region where the flange (8) is disposed when viewed from the direction along the central axis (A1).

Description

Technical Field

[0001] The present invention relates to a robot. Background Art

[0002] A joint of a robot is provided with a drive unit that drives a second member to rotate relative to a first member about a predetermined axis. The drive unit includes a motor and a speed reducer that decelerates the rotation of the motor, and the first member and the second member are connected by the speed reducer (for example, refer to Patent Document 1). In the robot of Patent Document 1, the central axis of the speed reducer and the central axis of the motor are coaxially arranged, and bolts for fastening the second member to the speed reducer are arranged at positions radially outside the flange of the motor.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese International Publication No. 2006 / 104216 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] When a hollow portion is provided in the rotation center portion of the speed reducer and a wire body such as a cable is arranged, or when the rotation of the motor is input to the speed reducer via a gear for primary reduction in order to obtain a reduction ratio, the central axis of the motor may be eccentric with respect to the central axis of the speed reducer. In this case, when viewed from the direction along the central axis, a part of the circumferential region of the speed reducer overlaps with the region where the flange of the motor is arranged, so it is difficult to arrange bolts for fastening the first member or the second member to the speed reducer.

[0008] When bolts are not fastened in the region where the flange of the motor is arranged, the larger the flange of the motor is, the more the first member or the second member and the speed reducer are not fastened in a large angular range, so the rigidity of the robot is greatly reduced.

[0009] Therefore, it is desired to sufficiently ensure the rigidity even when the motor is arranged eccentrically with respect to the speed reducer.

[0010] Means for Solving the Problems

[0011] One aspect of the present invention is a robot. The robot includes one or more rotary joints. Each rotary joint includes: a motor; a speed reducer that decelerates the rotation of the motor; and a first component and a second component. The first component and the second component are connected by the speed reducer and supported so as to be rotatable about the central axis of the speed reducer. On the first component of at least one of the rotary joints, a flange fixing portion for fixing the flange of the motor is provided at a position eccentric with respect to the central axis of the speed reducer. The bolts for fixing the first component to the speed reducer are also arranged within the region where the flange is arranged when viewed from the direction along the central axis. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 is a longitudinal sectional view of a rotary joint that is a part of a robot according to an embodiment of the present invention.

[0013] Figure 2 is Figure 1 a top view of the rotary joint of the robot.

[0014] Figure 3 is along Figure 1 a sectional view taken along the cutting line A - A of.

[0015] Figure 4 is showing Figure 1 a perspective view of the flange fixing portion of the robot.

[0016] Figure 5 is showing Figure 2 a top view of a modified example of the rotary joint of the robot.

[0017] Figure 6 is Figure 5 the same sectional view as that of the rotary joint of Figure 3 of.

[0018] Figure 7 is showing Figure 6 a sectional view of a modified example of.

[0019] Figure 8 is showing Figure 1 an enlarged longitudinal sectional view of another modified example of the rotary joint of the robot.

[0020] REFERENCE MARK DESCRIPTION:

[0021] 1: Rotary joint

[0022] 2: Motor

[0023] 3: Speed reducer

[0024] 4: Base (second component)

[0025] 5: Rotating body (first component)

[0026] 7: Shaft

[0027] 8: Flange part (flange)

[0028] 9: Flange fixing part

[0029] 10: Central hole

[0030] 11: Cylindrical part

[0031] 12: Fixing part

[0032] 15: Bolt

[0033] 16: Through hole

[0034] 19: Thick wall part

[0035] 20: Needle roller bearing

[0036] 21, 22: Notch part

[0037] A1: Vertical axis (central axis) Detailed implementation mode

[0038] The robot according to an embodiment of the present invention will be described below with reference to the accompanying drawings.

[0039] The robot of the present embodiment is, for example, a vertical multi-joint robot having six rotating joints 1.

[0040] As Figure 1 shown, one of the rotating joints 1 includes: a motor 2; a speed reducer 3 that decelerates the rotation of the motor 2; a base (second component) 4 provided on the ground F; and a rotating body (first component) 5 that is supported so as to be able to rotate relative to the base 4 about the vertical axis A1.

[0041] The base 4 and the rotating body 5 are connected by the speed reducer 3. Thus, the rotating body 5 is supported so as to be able to rotate relative to the base 4 about the central axis of the speed reducer 3, that is, the vertical axis A1. On the base 4, the speed reducer 3, and the rotating body 5, a hollow portion 6 penetrating in the up-down direction is provided near the vertical axis A1. Thus, it is possible to route a cable or other linear body (not shown) from the base 4 through the hollow portion 6 to the rotating body 5 near the vertical axis A1.

[0042] The motor 2 is arranged at a position eccentric with respect to the central axis of the speed reducer 3, i.e., the vertical axis A1, in order to avoid the hollow portion 6. That is, in the rotating body 5, the shaft 7 on which the drive gear 32 meshing with the input gear 31 of the speed reducer 3 is installed is vertically downward, and the flange fixing portion 9 of the flange plate portion (flange) 8 for fixing the motor 2 is arranged at a position eccentric with respect to the vertical axis A1 so as to avoid the hollow portion 6. In the figure, the reference numeral B1 is the rotation axis of the shaft 7.

[0043] The flange fixing portion 9 includes a cylindrical portion 11 and a fixing portion 12. The cylindrical portion 11 has a central hole 10 through which the shaft 7 of the motor 2 on which the drive gear 32 is installed passes. The fixing portion 12 extends in an outward flange shape at the upper end of the cylindrical portion 11 and fixes the flange plate 8 of the motor 2. The cylindrical portion 11 and the fixing portion 12 are integrally provided with the rotating body 5 at the upper part of the rotating body 5.

[0044] As Figure 2 shown, the fixing portion 12 is formed in a rectangular shape in plan view, and the rectangular shape has substantially the same shape and size as the flange plate 8 of the motor 2. The fixing portion 12 has four threaded holes 14 capable of fastening the mounting bolts 13 at positions corresponding to the four mounting holes (not shown) through which the mounting bolts 13 of the flange plate 8 of the motor 2 pass.

[0045] Here, as Figure 1 and Figure 2 shown, the speed reducer 3 and the rotating body 5 are fixed by fastening a plurality of bolts 15 in order to transmit a large torque. In order to avoid the central hollow portion 6 and reduce the number of bolts 15, the bolts 15 are arranged along the circumferential direction at a position close to the outer periphery of the speed reducer 3. In Figure 1 and Figure 2 , for simplicity of illustration, they are arranged in a single row along a single circle, but it is not limited thereto, and they may also be arranged in multiple rows or not in a row in the annular region outside the radial direction of the hollow portion 6.

[0046] Moreover, as described above, the flange fixing portion 9 is arranged at a position eccentric with respect to the central axis of the speed reducer 3, i.e., the vertical axis A1. Therefore, as Figure 2 shown, it is arranged at a position overlapping the arrangement circle of the bolts 15.

[0047] In the robot of the present embodiment, as Figure 2 shown, in plan view, in the region of the fixing portion 12 where the flange fixing portion 9 is arranged, the rotating body 5 and the speed reducer 3 are also fastened by the bolts 15.

[0048] That is, as Figure 1 and Figure 2As shown, in the area where the fixing part 12 is configured, a through hole 16 that vertically penetrates the flange fixing part 9 is also provided. A contact surface 17 that abuts against the head of the bolt 15 is formed inside the through hole 16.

[0049] Figure 3 Indicates a cross-sectional view taken along the cutting line A - A Figure 1 In the example shown, on the flange fixing part 9, a single through hole 16 is provided at a position overlapping with the cylindrical part 11. Figure 3

[0050] In the present embodiment, as Figure 3 and Figure 4 shown, on the outer peripheral surface of the cylindrical part 11, a thick wall part 19 that ensures the wall thickness around the through hole 16 is provided along the vertical direction. As Figure 1 shown, a needle bearing 20 is arranged in the central hole 10 of the cylindrical part 11, and the shaft 7 of the motor 2 is supported by the needle bearing 20 so as to be rotatable relative to the central hole 10.

[0051] According to the robot of the present embodiment configured in this way, the bolts 15 that fix the rotating body 5 and the speed reducer 3 also make the rotating body 5 and the speed reducer 3 closely contact in the area of the flange 8 where the motor 2 is arranged in a top view. Thus, there is an advantage that the flange fixing part 9 prevents the rotating body 5 and the speed reducer 3 from being loose in a large angle range, and the reduction of the rigidity of the robot can be prevented.

[0052] Moreover, as Figure 3 and Figure 4 shown, in order to achieve the above advantages, a thick wall part 19 is provided on the outer surface of the cylindrical part 11, and as Figure 1 shown, by adopting the needle bearing 20, the diameter of the central hole 10 is reduced, and thus the wall thickness around the through hole 16 through which the bolt 15 penetrates can be sufficiently ensured.

[0053] In the present embodiment, an example in which a through hole 16 that vertically penetrates and through which the bolt 15 penetrates is provided on the flange fixing part 9 has been described. Instead, as Figure 5 and Figure 6 shown, multiple through holes can be provided. Thus, the rotating body 5 and the speed reducer 3 can be made to closely contact more firmly.

[0054] In this case, as Figure 5 shown, at a part close to the outer periphery of the fixing part 12, the outer peripheral edge of the fixing part 12 can be cut off to provide a notch part 21 through which the bolt 15 passes.

[0055] ​In the present embodiment, the fixing portion 12 of the flange fixing portion 9 is configured as a rectangular shape having substantially the same shape and size as the flange 8 of the motor 2, and threaded holes 14 are provided at four locations. Instead, the outer peripheral edge of the fixing portion 12 may be cut away at the positions of the threaded holes 14 so that the number of the threaded holes 14 is three (or two).

[0056] By providing the thick wall portion 19 on the outer peripheral surface of the cylindrical portion 11 of the flange fixing portion 9, the wall thickness around the through hole 16 is ensured. Instead, as shown Figure 7 in the figure, a cutout portion 22 through which the bolt 15 passes may be provided on the outer peripheral surface of the cylindrical portion 11.

[0057] In the present embodiment, an example of the rotary joint 1 between the base 4 and the rotating body 5 applicable to the vertical articulated robot is shown. Instead, it may be applicable to other rotary joints or one or more rotary joints. It may also be applicable to the rotary joints of other arbitrary forms of robots such as the horizontal articulated robot.

[0058] In the present embodiment, the flange fixing portion 9 is provided integrally with the rotating body 5. Instead, as shown Figure 8 in the figure, it may be fixed to the rotating body 5 by bolts 15 in a detachable manner. In this case, since the rotating body 5 and the speed reducer 3 can be fastened by the bolts 15 in a state where the flange fixing portion 9 is removed from the rotating body 5, the through hole 16 through which the bolts 15 pass may not be provided in the flange fixing portion 9.

Claims

1. A robot, characterized in that, the robot is provided with more than one rotary joint, each of the rotary joints includes: a motor; a speed reducer that decelerates the rotation of the motor; and a first component and a second component, the first component and the second component are connected by the speed reducer and supported so as to be able to rotate around the central axis of the speed reducer, the speed reducer and the first component are fixed by a plurality of bolts, on the first component of at least one of the rotary joints, a flange fixing portion for fixing the flange of the motor is provided at a position eccentric with respect to the central axis of the speed reducer, the flange fixing portion includes: a cylindrical portion having a central hole through which the shaft of the motor passes; a fixing portion that extends in an outward flange shape at one end of the cylindrical portion and fixes the flange; and a through hole, one or more of the bolts are inserted through one or more of the through holes, and one or more of the through holes penetrate the flange fixing portion in the direction along the central axis, the bolts for fixing the first component to the speed reducer are also arranged in the area where the flange is arranged when viewed from the direction along the central axis, one of the plurality of bolts is inserted through the through hole, and this one bolt is arranged at a position overlapping the cylindrical portion when viewed from the direction along the central axis.

2. The robot according to claim 1, characterized in that, on the outer peripheral surface of the cylindrical portion, a thick wall portion for ensuring the wall thickness around the through hole is provided in the direction along the central axis.

3. The robot according to claim 1, characterized in that, on the outer peripheral surface of the cylindrical portion, a notch portion for avoiding interference with the bolt is provided in the direction along the central axis.

4. The robot according to claim 1, characterized in that, a needle roller bearing is provided in the cylindrical portion, and the needle roller bearing supports the shaft inserted into the central hole so as to be able to rotate.

5. The robot according to claim 1, characterized in that, the flange fixing portion is detachably provided on the first component, after the first component and the speed reducer in a state where the flange fixing portion is removed are fastened with bolts, the flange fixing portion is installed on the first component.

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