Articulated robot

Abstract

This articulated robot comprises an arm which includes a first arm portion that is rotatable about a first axis line, and a second arm portion that is linked with the first arm portion so as to be rotatable about a second axis line parallel with the first axis line. The articulated robot further comprises: a first motor that generates a rotational force for rotating the first arm portion about the first axis line; a second motor that is disposed in a position closer to the first axis line than the second axis line on the first arm portion, and that generates a rotational force for rotating the second arm portion; and a rotational force transmission portion that links the first arm portion and the second arm portion to transmit the rotational force generated by the second motor to the second arm portion, and that deforms to follow the rotation of the second arm portion relative to the first arm portion.

Description

[Technical Field]

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

[0002] A horizontal articulated robot (SCARA robot) such as that disclosed in Patent Document 1 is well known. This horizontal articulated robot includes a base fixed to a base and an articulated arm supported by the base. The arm includes a first arm supported on the base so as to be rotatable about a first vertical axis, a second arm connected to the tip of the first arm so as to be rotatable about a second vertical axis, and an actuating shaft disposed at the tip of the second arm. Various end effectors are attached to the tip of the actuating shaft.

[0003] The first arm is driven by a motor (first motor) arranged on a first axis, and the second arm is driven by a motor (second motor) arranged on a second axis. By driving the first arm and the second arm by these motors, the arm moves the end effector (operating axis) horizontally within a certain area centered on the base.

[0004] Horizontal articulated robots are required to drive their arms at higher speeds and with higher precision, and to achieve this, it is desirable for the inertia (moment of inertia) around the arm's rotation axis to be as small as possible. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2009-226567 Summary of the Invention

[0006] The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to further reduce the inertia (moment of inertia) around the rotation axis of the arm.

[0007] A multi-joint robot according to one aspect of the present invention is a multi-joint robot equipped with an arm including a first arm portion rotatable about a first axis and a second arm portion connected to the first arm portion so as to be rotatable about a second axis parallel to the first axis, and is equipped with: a first motor that generates a rotational force that rotates the first arm portion about the first axis; a second motor that is positioned at a position on the first arm portion closer to the first axis than the second axis and generates a rotational force that rotates the second arm portion; and a rotational force transmission portion that connects the first arm portion and the second arm portion and transmits the rotational force generated by the second motor to the second arm, and that deforms in response to the rotation of the second arm portion relative to the first arm portion. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a perspective view of a horizontal articulated robot (an articulated robot) according to a first embodiment. [Figure 2] FIG. 2 is a plan view (partial cross-sectional view) of the horizontal articulated robot. [Figure 3] FIG. 3 is a cross-sectional view of the horizontal articulated robot. [Figure 4] FIG. 4 is a perspective view for explaining the operation of the horizontal articulated robot. [Figure 5] FIG. 5 is a diagram (plan view) illustrating the operation of the horizontal articulated robot. [Figure 6] FIG. 6 shows a planar model (neutral state) of the horizontal articulated robot. [Figure 7] FIG. 7 is a planar model of the horizontal articulated robot (when the arm is in operation). [Figure 8] FIG. 8 is a schematic perspective view of a horizontal articulated robot according to the second embodiment. [Figure 9] FIG. 9 is a schematic perspective view of a horizontal articulated robot according to the third embodiment. [Figure 10] FIG. 10 is a side view (view taken along the X arrow in FIG. 9) of the horizontal articulated robot according to the third embodiment. [Figure 11] FIG. 11 is a schematic perspective view of a horizontal articulated robot according to the fourth embodiment. [Figure 12] FIG. 12 is a cross-sectional view of a horizontal articulated robot according to the fifth embodiment. [Figure 13] FIG. 13 is a cross-sectional view of a horizontal articulated robot according to the sixth embodiment. [Figure 14] FIG. 14 is a cross-sectional view of a main part of a horizontal articulated robot according to the seventh embodiment. [Figure 15] FIG. 15 is a cross-sectional view of a main part of a horizontal articulated robot according to the eighth embodiment. [Figure 16] FIG. 16 is a cross-sectional view of a horizontal articulated robot according to the ninth embodiment. [Figure 17] FIG. 17 is a cross-sectional view of a horizontally jointed robot according to a tenth embodiment. [Figure 18] FIG. 18 is a perspective view of a horizontally jointed robot according to the eleventh embodiment. [Figure 19] FIG. 19 is a plan view (partially cross-sectional view) of a horizontally jointed robot according to an eleventh embodiment. [Figure 20] FIG. 20 is a perspective view of a horizontal articulated robot according to the twelfth embodiment. [Figure 21] FIG. 21 is a plan view (partial cross-sectional view) of a horizontal articulated robot according to the twelfth embodiment. [Figure 22] FIG. 22 is a cross-sectional view of a horizontal articulated robot according to the twelfth embodiment. [Figure 23] FIG. 23 is an explanatory diagram (perspective view) of the operation of the horizontal articulated robot according to the twelfth embodiment. [Figure 24] FIG. 24 is an explanatory diagram (plan view) of the operation of the horizontal articulated robot according to the twelfth embodiment. [Figure 25] FIG. 25 is a schematic perspective view of a horizontal articulated robot according to the thirteenth embodiment. [Figure 26] FIG. 26 is a cross-sectional view of a horizontal articulated robot according to the fourteenth embodiment. [Figure 27] FIG. 27 is a schematic perspective view of a horizontal articulated robot according to the fourteenth embodiment. [Figure 28] FIG. 28 is a plan view (partial cross-sectional view) of a horizontal articulated robot according to the fifteenth embodiment. [Figure 29] FIG. 29 is a plan view (partial cross-sectional view) of a horizontal articulated robot according to the sixteenth embodiment. [Figure 30] FIG. 30 is a plan view (partial cross-sectional view) of a horizontal articulated robot according to the seventeenth embodiment. [Figure 31] FIG. 31 is a plan view (partially cross-sectional view) of a horizontal articulated robot according to a modification of the seventeenth embodiment. [Figure 32] FIG. 32 is a perspective view of a vertical articulated robot (18th embodiment). [Figure 33] FIG. 33 is a cross-sectional view of the tip of the robot arm of a vertical articulated robot. DETAILED DESCRIPTION OF THE INVENTION

[0009] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0010] [Configuration of an articulated robot] Fig. 1 is a perspective view showing a first embodiment of a horizontal articulated robot that is an example of the articulated robot of the present invention, Fig. 2 is a plan view (partially sectional view) of the horizontal articulated robot, and Fig. 3 is a sectional view of the horizontal articulated robot taken along a vertical plane.

[0011] The horizontal articulated robot 1 (hereinafter referred to as robot 1) shown in Figures 1 to 3 comprises a base portion 2 which is installed on a base BP, a robot arm 3 supported by this base portion 2, and a working shaft 7 provided at the tip of this robot arm 3.

[0012] The robot arm 3 includes a first arm 4 rotatably connected to the base 2 about an axis A1, a second arm 5 rotatably connected to the first arm 4 about an axis A2, and a rotational force transmission unit 6 for rotating the second arm 5 relative to the first arm 4. The axes A1 and A2 are perpendicular axes parallel to each other. The axis A1 is an example of the "first axis" in the present invention, and the axis A2 is an example of the "second axis" in the present invention.

[0013] The base portion 2 is a hollow, rectangular parallelepiped structure having rigidity. A first motor M1 is provided inside the base portion 2. The first motor M1 is a motor that drives the first arm portion 4. The first motor M1 is a servo motor with an integrated reducer, in which a reducer M1b is integrally provided on a motor body M1a. The reducer M1b is an RV reducer, a Cyclo reducer (registered trademark), a Harmonic Drive (registered trademark), or the like. Second and fourth motors M2 and M4, which will be described later, are also servo motors with an integrated reducer, in which a reducer is integrally provided on a motor body. Note that a third motor M3, which will be described later, and a fourth motor M4 of a ninth embodiment, which will be described later, do not include a reducer.

[0014] The first motor M1 is fixed to the upper wall 2a of the base 2 in an upward orientation with the reducer M1b positioned on the upper side. An opening is formed in the upper wall 2a, and the output shaft of the reducer M1b is fixed through this opening to the lower wall 4b at one longitudinal end (base end) of the first arm 4. With this configuration, the first arm 4 is driven by the first motor M1 to rotate (pivot) around the axis A1 with the base end serving as a fulcrum.

[0015] The second arm 5 is located above the first arm 4, and one longitudinal end (base end) thereof is rotatably connected to the other longitudinal end (tip end) of the first arm 4. More specifically, a hollow shaft 5c provided on the lower wall 5b of the second arm 5 is held by the inner ring of a bearing B4 provided on the upper wall 4a of the first arm 4. With this configuration, the second arm 5 is connected to the first arm 4 so as to be rotatable around the axis A2 with its base end as a fulcrum. Both the first arm 4 and the second arm 5 have a hollow structure, and the internal spaces of both arms 4, 5 are in communication with each other via the hollow shaft 5c.

[0016] The working shaft 7 is disposed at the other longitudinal end (tip) of the second arm unit 5, i.e., at the tip of the robot arm 3. The working shaft 7 is a splined shaft that extends vertically. The working shaft 7 passes through the second arm unit 5 and is supported so as to be movable in the up and down direction (axial direction) and rotatable about its axis relative to the second arm unit 5, and is driven by a drive mechanism unit 8.

[0017] The drive mechanism 8 includes a third motor M3, a threaded shaft 34 arranged parallel to the work shaft 7 and rotatably supported by the third motor M3, a nut member 35 attached to the threaded shaft 34, and a connecting member 32 connecting the upper end of the work shaft 7 to the nut member 35. The drive mechanism 8 also includes a fourth motor M4 and a spline nut 31 attached to the work shaft 7 and connected to the reducer M4b of the fourth motor M4. When the threaded shaft 34 is rotated by the drive of the third motor M3, this rotational motion is converted into vertical motion of the work shaft 7 via the nut member 35 and the connecting member 36, causing the work shaft 7 to move up and down. The work shaft 7 is also rotated by the drive of the fourth motor M4. The fourth motor M4 is a hollow motor with a through hole that penetrates in the vertical direction, and the work shaft 7 is arranged to pass through the centers of the fourth motor M4 and the spline nut 31.

[0018] A hollow cover member 30 that is elongated in the vertical direction is fixed to the tip of the second arm unit 5. The cover member 30 is fixed to the upper wall portion 5a of the second arm unit 5, and covers the drive mechanism unit 8 and the portions of the second arm unit 5 that protrude upward from the upper wall portion 5a.

[0019] A work tool (end effector) not shown is attached to the tip (lower end) of the work shaft 7. For example, a work tool for performing a predetermined operation on a workpiece, such as a chuck device for gripping and transporting the workpiece, a processing device for performing various processes such as welding on the workpiece, or a measuring device for measuring the workpiece, is attached to the tip of the work shaft 7.

[0020] A second motor M2 that generates a rotational force about an axis A3 parallel to the axes A1 and A2 is disposed on the first arm 4 at a position closer to the axis A1 than the axis A2, i.e., at a position between the axis A2 and the axis A1 but excluding the axis A2. The second motor M2 drives the second arm 5.

[0021] As described above, the second motor M2 is not disposed on the axis A2, but is disposed at a position offset from the axis A2 toward the axis A1. Therefore, the rotational force of the second motor M2 is transmitted to the second arm unit 5 via the rotational force transmission unit 6, so that the second arm unit 5 is driven to rotate (pivot) around the axis A2 with the base end of the second arm unit 5 as a fulcrum.

[0022] The rotational force transmission unit 6 connects the first arm unit 4 and the second arm unit 5 to transmit the rotational force, and is configured to deform in response to the rotation of the second arm unit 5 relative to the first arm unit 4. This point will be described in detail below.

[0023] [Configuration of rotational force transmission section] The second motor M2 that drives the second arm portion 5 is oriented downward with the reducer M2b located on the lower side, and the output shaft of the reducer M2b is fixed to the upper wall portion 4a of the first arm portion 4.

[0024] The rotational force transmission unit 6 includes a first base 10 that rotates about axis A3 due to the rotational force of the second motor M2, a second base 12 that is supported on the second arm unit 5 so as to be rotatable about axis A4, and an expansion / contraction unit 13 that connects the first base 10 and the second base 12 and expands and contracts (deforms) in accordance with changes in the distance between the first base 10 and the second base 12. The axis A3 and the axis A4 are perpendicular axes that are parallel to each other, and the axis A3 is an example of the "third axis" in the present invention, and the axis A4 is an example of the "fourth axis" in the present invention.

[0025] The first base 10 is a hollow box-shaped member including a frame 20 and a cover 21, and is configured to surround the second motor M2. The frame 20 has an L-shaped cross section, including a plate-like horizontal portion 20a that fits along the upper wall portion 4a of the first arm 4 and a plate-like upright portion 20b that rises vertically upward from one end of the horizontal portion 20a. The horizontal portion 20a is fixed to the motor main body M2a of the second motor M2 or the body of the reducer M2b (the portion joined to the motor main body M2a). As described above, the output shaft of the reducer M2b of the second motor M2 is fixed to the first arm 4. Therefore, when the second motor M2 is operated, the motor main body M2a and the first base 10 (frame 20) rotate together around the axis A3 relative to the first arm 4.

[0026] The second base 12 is disposed between the working shaft 7 and axis A2 in the longitudinal direction of the second arm 5, and is supported rotatably about axis A4 relative to the upper surface (upper wall 5a) of the second arm 5. Similar to the first base 10, the second base 12 is a hollow box-shaped member comprising a frame 22 and a cover 23. The frame 22 has an L-shaped cross section and comprises a plate-like horizontal portion 22a that fits along the upper wall 5a of the second arm 5, and a plate-like upright portion 22b that rises vertically upward from one end of the horizontal portion 22a.

[0027] The horizontal portion 22a of the frame 22 is formed with a circular opening 22c that penetrates vertically along the axis A4, and a sleeve portion 22d that extends downward from the periphery of the opening 22c. The sleeve portion 22d is held by an inner ring of a bearing B5 that is provided on the upper wall portion 5a of the second arm portion 5. With this configuration, the second base portion 12 is supported relative to the second arm portion 5 so as to be rotatable about the axis A4.

[0028] The expansion / contraction section 13 is a link mechanism consisting of a first link 14 and a second link 15. The first link 14 is an example of a "first link member" in the present invention, and the second link 15 is an example of a "second link member" in the present invention.

[0029] Both links 14, 15 are slender hollow plates having a thickness in the width direction (vertical direction in FIG. 2) of the first link 14 and the second link 15 (hereinafter sometimes referred to as the arm main body). The first link 14 and the second link 15 have one longitudinal end portion overlapping each other in the thickness direction and are connected to each other at the one end portion so as to be rotatable about an axis A5 extending horizontally. Specifically, a hollow shaft 14a provided on the side wall portion of the first link 14 is held by an inner ring of a bearing B13 provided on the second link 15, thereby rotatably connecting the first link 14 and the second link 15.

[0030] As shown in FIG. 2, when the first arm section 4 and the second arm section 5 are aligned in a straight line (hereinafter sometimes referred to as the neutral state of the robot arm 3 or the neutral state of the arm body), the first link 14 is located outside (opposite the arm body side) of the second link 15. Both links 14, 15 are bent so as to be convex upward in side view, and are connected to the respective bases 10, 12 as follows: Note that the first link 14 may also be located inside the second link 15.

[0031] The other end of the first link 14 is rotatably connected to the upright portion 20b of the frame 20 of the first base 10 about an axis A6 parallel to the axis A5. The other end of the second link 15 is rotatably connected to the upright portion 22b of the frame 22 of the second base 12 about an axis A7 parallel to the axis A5. Specifically, a hollow shaft 14b provided on the side surface of the first link 14 is held by an inner ring of a bearing B14 provided on the upright portion 20b of the first base 10. A hollow shaft 15a provided on the side wall of the second link 15 is held by an inner ring of a bearing B15 provided on the upright portion 22b of the second base 12. This rotatably connects the second link 15 to the second base 12 and the first link 14 to the first base 10. The axis A5 is an example of a "fifth axis" in the present invention.

[0032] 2 and 3, cables 100 such as electric wires for driving the first to fourth motors M1 to M4 are introduced inside the base unit 2. A flexible cable piping L1 is provided in an arch shape between the base unit 2 and the robot arm 3, specifically between the base unit 2 and the cover 21 of the first base unit 10 in the rotational force transmission unit 6, connecting them outside the robot. The cable piping L1 is, for example, a flexible tube made of resin.

[0033] The cable 100 is guided from the base 2 into the interior of the rotational force transmission unit 6 through the cable piping L1, and then guided through the interior of the rotational force transmission unit 6 to the tip of the second arm 5. More specifically, the cable 100 is guided from the first base 10 of the rotational force transmission unit 6 through the hollow shaft 14b into the first link 14, and from the first link 14 through the hollow shaft 14a into the second link 15. The cable 100 is further guided from the second link 15 through the hollow shaft 15a into the second base 12, and from the second base 12 through the opening 22c and the sleeve 22d into the second arm 5. Of the cables 100, the cable for the first motor is connected to the first motor M1 inside the base 2, and the cable for the second motor is connected to the second motor M2 inside the first base 10. The cables for the third and fourth motors are connected to the third and fourth motors M3 and M4, respectively, inside the second arm 5.

[0034] If a work tool (end effector) is attached to the work shaft 7, a cable for driving the work tool can be routed together with the cable 100.

[0035] [Robot 1 movement] 4 and 5 are explanatory diagrams of the operation of the robot 1, with Fig. 4 being a perspective view and Fig. 5 being a plan view, each showing the operation of the robot 1. Note that some members such as the covers 21, 23 of the bases 10, 12 of the rotational force transmission unit 6 and the cable piping L1 are omitted from Figs.

[0036] 4(a) and 5(a) show the neutral state of the robot arm 3. When the second motor M2 is driven in this neutral state, its rotational force is transmitted to the second arm portion 5 via the rotational force transmission unit 6. This causes the second arm portion 5 to rotate about the axis A2 relative to the first arm portion 4. As described above, the output shaft of the reducer M2b of the second motor M2 is fixed to the first arm portion 4, and the motor main body M2a is fixed to the first base portion 10 of the rotational force transmission unit 6. Therefore, when the second motor M2 is driven, the motor main body M2a rotates integrally with the first base portion 10 about the axis A3.

[0037] When the second arm unit 5 is driven in the forward direction by the second motor M2 in the neutral state of the robot arm 3, the second arm unit 5 rotates clockwise in a plan view (in the direction of the arrow R1 in the figure). At this time, the rotation angle of the second arm unit 5 increases from the neutral state, and the axis A4 and the axis A3 approach each other. As a result, the extension / contraction unit 13 is folded so that the bending angle of the first link 14 and the second link 15 becomes smaller, as shown in Figures 4(b), (c) and 5(b), (c).

[0038] On the other hand, when the second arm unit 5 is reversely driven by the second motor M2, the second arm unit 5 rotates counterclockwise in plan view (the direction of arrow R2 in the figure). Similarly, in this case, when the rotation angle of the second arm unit 5 increases from the neutral state, the extendable unit 13 is folded so that the bending angle between the first link 14 and the second link 15 decreases, as shown in Figures 4(d) and (e) and 5(d) and (e). In other words, the extendable unit 13 extends and contracts in accordance with the rotation of the second arm unit 5 relative to the first arm unit 4.

[0039] Although not shown in the figure, in addition to the rotational driving of the second arm section 5 by the second motor M2, the first arm section 4 is rotationally driven around the axis A1 by the first motor M1, so that in the robot 1, the working axis 7 (end effector) moves horizontally to any position within the movable area indicated by the symbol Ar in Figure 5(a).

[0040] 4 and 5 have described the operation of the second arm unit 5 from the neutral state of the robot arm 3, but the second arm unit 5 can be driven by the second motor M2 to operate nonstop in the order of (e) → (d) → (a) → (b) → (c) or (c) → (b) → (a) → (d) → (e) in Fig. 4. In other words, in a plan view of the robot 1, the second arm unit 5 can rotate clockwise (in the R1 direction) or counterclockwise (in the R2 direction) relative to the first arm unit 4, that is, it can continuously switch from a so-called right-handed arm state to a left-handed arm state, or from a left-handed arm state to a right-handed arm state.

[0041] [effect] According to the robot 1 described above, the second motor M2, which is conventionally disposed on the axis A2 of rotation of the second arm unit 5 (Patent Document 1), is disposed closer to the axis A1 than the axis A2. Therefore, the center of gravity of the robot arm 3 is closer to the axis A1, thereby reducing the inertia (moment of inertia) of the robot arm 3 around the axis A1. In this case, since the rotational force of the second motor M2 is transmitted to the second arm unit 5 via the rotational force transmission unit 6, the effect of the increased weight of the rotational force transmission unit 6 on the inertia must be considered. However, the weight of the rotational force transmission unit 6 is sufficiently small compared to the weight of the second motor M2, which includes the motor body M2a and the reducer M2b, and the effect of the rotational force transmission unit 6 on the inertia is extremely small. Therefore, the configuration of the robot 1 described above can be said to reduce the inertia of the robot arm 3 around the axis A1 compared to conventional horizontal articulated robots.

[0042] Moreover, with this robot 1, it is possible to drive the second arm unit 5 around the axis A2 with torque and speed (angular velocity) comparable to those in the case where the second motor M2 is arranged on the axis A2. This point will be explained below with reference to the drawings.

[0043] Fig. 6 is a plan view of the robot 1 in a neutral state. Fig. 7 is a plan view of the second arm unit 5 in operation. Specifically, this figure shows a state in which the second arm unit 5 is reversely driven and the working shaft 7 is brought into contact with an obstacle, restricting the rotation of the second arm unit 5. Here, it is assumed that the link lengths B of the links 14, 15 of the extension / contraction unit 13 of the rotational force transmission unit 6 are equal to each other, and that the rotational force transmission unit 6 is configured to move the second arm unit 5 by 2θ around the axis A2 relative to the rotation angle θ of the second motor M2.

[0044] 6 and 7, if the torque around the axis A3 generated by the second motor M2 is T1, the torque around the axis A2 in this case is T2, and the rotational force transmitted to the second arm 5 via the rotational force transmission unit 6 is F, then T1 = F × 2B × cos θ. Therefore, this formula can be transformed to F=T1 / (2B×cosθ)……(Formula 1) On the other hand, if the rotational force of the second arm portion 5 around the axis A2 is F', then F′=F×cosθ=T1 / (2B)……(Formula 2) Therefore, from Equation 1, T2=F′×B=T1 / 2……(Formula 3) In other words, the torque T2 about the axis A2 is half the torque T1 about the axis A3. In other words, the torque T2 about the axis A2 when the second motor M2 is disposed on the axis A3 is half the torque when the second motor M2 is disposed on the axis A2.

[0045] Therefore, if the reduction ratio of the reducer M2b of the second motor M2 is set to twice that when the second motor M2 is arranged on the axis A2, the torque T2 about the axis A2 is doubled and the speed (angular velocity) of the second arm unit 5 about the axis A2 is halved, making it possible to drive the second arm unit 5 about the axis A2 with torque and speed (angular velocity) comparable to those when the second motor M2 is arranged on the axis A2. In this case, changing the reduction ratio of the reducer M2b does not result in much increase in the weight of the second motor M2.

[0046] Note that the inertia (moment of inertia) seen from the second motor M2 is reduced by the square of the reduction ratio, so if the reduction ratio is doubled as described above, the inertia around the axis A2 will be 1 / 4. Therefore, with the robot 1 described above, compared to when the second motor M2 is disposed on the axis A2, it is possible to reduce not only the inertia around the axis A1 but also the inertia when the position of the second motor M2 is used as a reference to the same or less, making it possible to increase the torque of the second motor M2 without having to worry about the inertia around the axis A1.

[0047] [Second embodiment] 8 is a schematic perspective view of the robot 1 according to the second embodiment. (a) in the figure shows the robot 1 with the robot arm 3 in a neutral state. The configuration of the rotational force transmission unit 6 of the robot 1 according to the second embodiment differs from that of the first embodiment in the following points.

[0048] In the first embodiment, the links 14, 15 of the expandable portion 13 are bent so as to be convex upward and are connected to the bases 10, 12. In contrast, in the second embodiment, the first link 14 and the second link 15 are bent so as to be convex downward and are connected to the bases 10, 12.

[0049] In the robot 1 of the second embodiment, when the second arm unit 5 rotates relative to the first arm unit 4, the extension / contraction unit 13 is folded so that the bending angle between the first link 14 and the second link 15 becomes smaller, as shown in Figures 8(b) and 8(c). Therefore, the rotational force transmission unit 6 transmits the rotational force of the second motor M2 to the second arm unit 5, and also deforms in accordance with the rotation of the second arm unit 5, i.e., it extends and contracts, as in the first embodiment.

[0050] The configuration of the robot 1 of the second embodiment as described above can also achieve the same effects as those of the first embodiment. Note that the bases 10, 12 of the second embodiment are configured to be taller than those of the first embodiment, and the links 14, 15 are supported at a height that prevents interference between the arm units 4, 5 and the extendable unit 13 when the extendable unit 13 is folded as the second arm unit 5 rotates.

[0051] [Third embodiment] Fig. 9 is a schematic perspective view of a robot 1 according to a third embodiment. (a) in the figure shows the robot 1 with the robot arm 3 in a neutral state. Fig. 10 is a side view of the robot 1 (view taken along the X arrow in Fig. 9). The robot 1 according to the third embodiment differs from the first embodiment in the following respects regarding the configuration of the rotational force transmission unit 6.

[0052] In the first embodiment, for each link 14, 15 of the telescopic section 13, the axis A6 is perpendicular to the axis A3, and similarly, the axis A7 is perpendicular to the axis A4. That is, the angle that the axis A6 forms with respect to the axis A3 and the angle that the axis A7 forms with respect to the axis A4 are both 90°. In contrast, in the third embodiment, as shown in FIG. 10, the angle θa that the axis A6 forms with respect to the axis A3 and the angle θb that the axis A7 forms with respect to the axis A4 are set to the same acute angle. Therefore, the upright portion 20b of the frame 20 in the first base portion 10 and the upright portion 22b of the frame 22 in the second base portion 12 are both inclined with respect to the vertical axis.

[0053] In the configuration of the third embodiment, when the second arm unit 5 rotates relative to the first arm unit 4, the extension / contraction unit 13 is folded in response to this rotation so that the bending angle between the first link 14 and the second link 15 becomes smaller, as shown in Figures 9(b) and 9(c). Therefore, similar to the first embodiment, the rotational force transmission unit 6 transmits the rotational force of the second motor M2 to the second arm unit 5 and deforms in response to the rotation of the second arm unit 5, i.e., it extends and contracts.

[0054] The configuration of the robot 1 of the third embodiment can also achieve the same effects as those of the first embodiment. Note that the angle θa formed by the axis A6 with respect to the axis A3 and the angle θb formed by the axis A7 with respect to the axis A4 are desirably 90° as in the first embodiment from the viewpoint of avoiding interference between the second arm unit 5 and the extendable unit 13. If the angles θa and θb are smaller than 90°, there is a concern that the second arm unit 5 will interfere with the extendable unit 13. Therefore, in the third embodiment, the angles θa and θb are set within a range in which the second arm unit 5 and the extendable unit 13 will not interfere with each other, for example, within a range of 10° or more and less than 90°.

[0055] [Fourth embodiment] 11 is a schematic perspective view of the robot 1 according to the fourth embodiment. (a) in the figure shows the robot 1 with the robot arm 3 in a neutral state. The configuration of the rotational force transmission unit 6 of the robot 1 according to the fourth embodiment differs from that of the first embodiment in the following respects.

[0056] In the first embodiment, when the robot arm 3 is in the neutral state, the rotational force transmission unit 6 is configured so that the extension / contraction unit 13 is located on the outer side in the width direction of the arm main body (first arm section 4 and second arm section 5) in a plan view (see FIG. 2). In contrast, in the fourth embodiment, the rotational force transmission unit 6 is configured so that the extension / contraction unit 13 is located along the center in the width direction of the arm main body, that is, on a straight line intersecting with the axes A2 to A4.

[0057] Specifically, the frames 20, 22 of each base 10, 12 have horizontal portions 20a, 22a formed in a disk shape, with standing portions 20b, 22b provided at the center. One end of each of the first link 14 and the second link 15 is bifurcated, and the other end is inserted into the bifurcated portion, rotatably connecting the first link 14 and the second link 15. The end of the first link 14 on the first base 10 side is bifurcated, and the first link 14 is rotatably connected to the standing portion 20b with the standing portion 20b inserted into the bifurcated portion. Similarly, the end of the second link 15 on the second base 12 side is bifurcated, and the second link 15 is rotatably connected to the standing portion 22b with the standing portion 22b inserted into the bifurcated portion.

[0058] In the robot 1 of the fourth embodiment, the second motor M2 is disposed inside the first arm unit 4. The second motor M2 is fixed to the upper wall unit 4a in an upward orientation with the reducer M2b located on the upper side, and the output shaft of the reducer M2b is fixed to the frame 20 of the first base unit 10. Although not shown in the drawings, the wiring structure of the cable 100 can be the same as that of the fifth and sixth embodiments described below.

[0059] In the configuration of this fourth embodiment, as in the first embodiment, when the second arm portion 5 rotates relative to the first arm portion 4, the extension / contraction portion 13 is folded so that the bending angle of the first link 14 and the second link 15 becomes smaller, as shown in Figures 11(b), (c), (d) and (e).

[0060] The configuration of the robot 1 of the fourth embodiment as described above can also provide the same effects as those of the first embodiment. In addition, according to the robot 1 of the fourth embodiment, the rotational force transmission unit 6 is configured so that the extension / contraction unit 13 is located inside the width direction of the arm body when the robot arm 3 is in the neutral state, which has the advantage that the entire robot is more compact than the robot 1 of the first embodiment.

[0061] [Fifth embodiment] 12 is a vertical cross-sectional view showing the robot 1 according to the fifth embodiment. The robot 1 according to the fifth embodiment differs from the first embodiment mainly in the wiring structure of the cable 100 in the following respects.

[0062] In the first embodiment, the cable 100 is guided from the base unit 2 to the rotational force transmission unit 6 through the cable piping L1, and is then guided to the tip of the second arm unit 5 through the inside of the rotational force transmission unit 6. In the fifth embodiment, as shown in FIG. 12 , the cable piping L1 is provided between the base unit 2 and the second arm unit 5.

[0063] The cable 100 is guided from the base 2 into the second arm 5 through the cable piping L1. More specifically, the cable 100 is guided into the second arm 5 at a position between the working shaft 7 and the second base 12 of the rotational force transmission unit 6. Of the cable 100, the cables for the third and fourth motors are connected to the third and fourth motors M3 and M4, respectively, inside the second arm 5. The cable for the second motor is introduced from the second arm 5 into the first arm 4 through the hollow shaft 5c and connected to the second motor M2 inside the first arm 4. The cable for the first motor is connected to the first motor M1 inside the base 2, as in the first embodiment.

[0064] In the robot 1 of the fifth embodiment, the second motor M2 is oriented upward with the reducer M2b located on the upper side, and the reducer M2b is fixed to the upper wall 4a of the first arm 4. The output shaft of the reducer M2b is fixed to the frame 20 of the first base 10 of the rotational force transmission unit 6.

[0065] The basic structure of the robot 1 of the fifth embodiment is the same as that of the first embodiment, and therefore the robot 1 of the fifth embodiment can also enjoy the same effects as those of the first embodiment.

[0066] [Sixth embodiment] 13 is a vertical cross-sectional view of the robot 1 according to the sixth embodiment. The robot 1 according to the sixth embodiment differs from the first embodiment mainly in the wiring structure of the cable 100 in the following respects.

[0067] In the first embodiment, a flexible cable pipe L1 (not shown in FIG. 1) made of a flexible tube is provided, and the cable 100 is guided through the cable pipe L1 from the base portion 2 to the rotational force transmission portion 6. In the sixth embodiment, instead of the cable pipe L1 of the first embodiment, a cable guide portion 40 made of a rigid hollow structure is provided on the upper portion of the base portion 2.

[0068] The cable guide unit 40 has an inverted L-shape and includes a vertical guide unit 41 extending upward from the upper surface of the base unit 2 and a horizontal guide unit 42 extending horizontally from the upper end of the vertical guide unit 41. The vertical guide unit 41 is provided on the upper surface of the base unit 2 at a position outside the movable area of ​​the first arm unit 4. The horizontal guide unit 42 is located above the upper surface of the first arm unit 4, with its tip positioned on the axis A1.

[0069] An opening 42a is formed in the lower surface of the tip end of the lateral guide portion 42 at a position corresponding to the axis A1. Also, an opening 4c is formed in the upper surface (upper wall portion 4a) of the first arm portion 4 so as to face the opening 42a.

[0070] 13, the cable 100 is introduced into the cable guide section 40 through an opening 2b formed in the upper wall section 2a of the base section 2, is guided from the cable guide section 40 into the inside of the first arm section 4 through the openings 42a and 42c, and is further guided from the first arm section 4 to the tip of the second arm section 5 through the hollow shaft 5c. Of the cable 100, the cable for the second motor is connected to the second motor M2 inside the first arm section 4, and the cables for the third and fourth motors are connected to the third motor M3 and the fourth motor M4, respectively, inside the second arm section 5. The cable for the first motor is connected to the first motor M1 inside the base section 2, as in the first embodiment.

[0071] In the robot 1 of the sixth embodiment, the second motor M2 is oriented upward as in the fifth embodiment, and the reducer M2b is fixed to the upper wall 4a of the first arm 4. The output shaft of the reducer M2b is fixed to the frame 20 of the first base 10 of the rotational force transmission unit 6.

[0072] The basic structure of the robot 1 of the sixth embodiment is the same as that of the first embodiment, and therefore the robot 1 of the sixth embodiment can also enjoy the same effects as those of the first embodiment. In addition, the robot 1 of the sixth embodiment has the advantage that the cable piping L1 is omitted, thereby reducing the risk of interference between the cable piping L1 and external equipment.

[0073] [Seventh embodiment] 14 is a cross-sectional view of the main parts of the robot 1 according to the seventh embodiment taken along a vertical plane. The robot 1 according to the seventh embodiment differs from the first embodiment in the following respects regarding the wiring structure of the rotational force transmission unit 6 and the cable 100.

[0074] In the robot 1 of the seventh embodiment, a second motor M2 is disposed on the axis A1. That is, the second motor M2 is disposed with respect to the first arm unit 4 so as to generate a rotational force about the axis A1, and a rotational force transmission unit 6 is provided corresponding to the arrangement of this second motor M2. The basic configuration of the rotational force transmission unit 6 is the same as in the first embodiment, but the link lengths of the links 14, 15 are different from those in the first embodiment.

[0075] Furthermore, in the seventh embodiment, instead of the cable piping L1 of the first embodiment, a cable guide section 40 similar to that of the sixth embodiment is provided on the upper part of the base section 2. The lateral guide section 42 of the cable guide section 40 is provided above the upper surface of the first base section 10 of the rotational force transmission section 6, i.e., above the upper surface of the cover 21. The cover 21 is provided with an opening 21a at a position opposite to the opening 42a of the cable guide section 40 (lateral guide section 42), i.e., on the axis A1.

[0076] 14, the cable 100 is introduced into the cable guide section 40 through an opening 2b formed in the upper wall section 2a of the base section 2, and is then guided from the cable guide section 40 into the inside of the first base section 10 of the rotational force transmission section 6 via the openings 42a and 21a. Then, as in the first embodiment, the cable 100 is guided through the inside of the rotational force transmission section 6 to the tip end of the second arm section 5.

[0077] The basic structure of the robot 1 of the seventh embodiment is the same as that of the first embodiment, and therefore the robot 1 of the seventh embodiment can also enjoy the same effects as those of the first embodiment. Moreover, in the seventh embodiment, the second motor M2 is disposed on the axis A1, which is the center of rotation of the first arm section 4, and therefore the center of gravity of the robot arm 3 is closer to the axis A1 than when the second motor M2 is disposed on the axis A3. Therefore, according to the robot 1 of the seventh embodiment, the inertia (moment of inertia) of the robot arm 3 about the axis A1 is reduced compared to the robot 1 of the first embodiment.

[0078] [Eighth embodiment] 15 is a cross-sectional view of a main part of a robot 1 according to an eighth embodiment, taken along a vertical plane. The robot 1 according to the eighth embodiment has a configuration in which the second motor M2 is arranged on the axis A1 in the robot 1 according to the sixth embodiment (see FIG. 13) already described. A rotational force transmission unit 6 is provided corresponding to the arrangement of this second motor M2. The basic configuration of the rotational force transmission unit 6 is the same as that of the first embodiment.

[0079] Specifically, in the eighth embodiment, the second motor M2 is disposed so as to vertically penetrate the lateral guide portion 42 of the cable guide unit 40 through the opening 4c of the first arm portion 4 and the opening 42a of the lateral guide portion 42. The first base portion 10 of the rotational force transmission unit 6 is disposed above the lateral guide portion 42, and the output shaft of the reducer M2b of the second motor M2 is fixed to the frame 20 (horizontal portion 20a) of this first base portion 10.

[0080] As in the sixth embodiment, the cable 100 is introduced from the base 2 into the cable guide 40, and is guided from the cable guide 40 through the openings 42a and 42c along the second motor M2 into the inside of the first arm 4. The cable 100 is then guided to the tip of the second arm 5 through the insides of the first arm 4 and the second arm 5.

[0081] The basic structure of the robot 1 of the eighth embodiment is the same as that of the first embodiment, and therefore the robot 1 of the eighth embodiment can also enjoy the same effects as those of the first embodiment. Furthermore, in the eighth embodiment, the second motor M2 is disposed on the axis A1 that is the center of rotation of the first arm section 4, and therefore, similar to the robot 1 of the seventh embodiment, it is possible to reduce the inertia (moment of inertia) of the robot arm 3 about the axis A1 compared to the robot 1 of the first embodiment.

[0082] [Ninth embodiment] 16 is a vertical cross-sectional view of the robot 1 according to the ninth embodiment. The robot 1 according to the ninth embodiment has a basic structure in common with the robot 1 according to the sixth embodiment (see FIG. 13), but the specific configurations of the working axis 7 and the drive mechanism 8 differ from those of the sixth embodiment in the following respects.

[0083] In the robot 1 of the ninth embodiment, the working shaft 7 is a ball screw spline shaft, and is disposed on the axis A4 so as to vertically pass through the second base 12 of the rotational force transmission unit 6. More specifically, the working shaft 7 passes through the second base 12 in the vertical direction through the bearing B5, the opening 22c of the frame 22 of the second base 12, and the opening 23a formed in the cover 23.

[0084] The work shaft 7 is inserted into a ball screw nut 36a rotatably supported via a bearing B20 on the upper wall portion 5a of the second arm portion 5, and a ball spline nut 38a rotatably supported via a bearing B21 on the lower wall portion 5b. The ball screw nut 36a is driven by a third motor M3, and the ball spline nut 38a is driven by a fourth motor M4, each via a belt transmission mechanism.

[0085] Specifically, the third motor M3 and the fourth motor M4 are disposed facing each other vertically at a position between the axis A4 and the axis A2 on the second arm portion 5, with their output shafts located within the second arm portion 5. A transmission belt 36d is attached between a pulley 36b attached to the ball screw nut 36a and a pulley 36c fixed to the output shaft of the third motor M3, and a transmission belt 38d is attached between a pulley 38b attached to the ball spline nut 38a and a pulley 38c fixed to the output shaft of the fourth motor M4. With this configuration, when the ball screw nut 36a is driven to rotate by the third motor M3, the working shaft 7 moves vertically relative to the second arm portion 5. When the ball screw nut 36a and the ball spline nut 38a are driven to rotate in synchronization by the third motor M3 and the fourth motor M4, the working shaft 7 rotates about the axis A4.

[0086] In the ninth embodiment, the drive mechanism 8 is thus configured by the third motor M3, the fourth motor M4, the ball screw nut 36a, the ball spline nut 38a, and the belt transmission mechanism described above.

[0087] The basic structure of the robot 1 of the ninth embodiment is the same as that of the first embodiment, and therefore the robot 1 of the ninth embodiment can also enjoy the same effects as those of the first embodiment.

[0088] Additionally, in the robot 1 of the ninth embodiment, the working shaft 7 is arranged on the axis A4 and is configured to pass through the second base portion 12 of the rotational force transmission unit 6 in the vertical direction, so that the rotational force transmission unit 6 does not interfere with the drive mechanism unit 8 of the working shaft 7 when the second arm unit 5 is in operation. Therefore, there is no restriction on the movable area Ar of the second arm unit 5 to avoid such interference, which has the advantage of contributing to an increase in the movable area Ar.

[0089] [Tenth embodiment] 17 is a vertical cross-sectional view of the robot 1 according to the tenth embodiment. The specific configuration of the rotational force transmission unit 6 of the robot 1 according to the tenth embodiment differs from that of the first embodiment in the following respects.

[0090] In the first embodiment, the extension / contraction section 13 of the rotational force transmission section 6 was configured by two links 14, 15 connected to each other at their ends, but the extension / contraction section 13 of the tenth embodiment is configured by a magic hand-type link mechanism (lage tongs) that combines multiple parallel link mechanisms, as shown in Figure 17.

[0091] Some or all of the individual links constituting the extension / contraction unit 13 have a hollow structure, and the cable 100 guided from the base unit 2 to the rotational force transmission unit 6 through the cable piping L1 is guided to the tip of the second arm unit 5 through the inside of the link of the extension / contraction unit 13. This is the same as in the first embodiment.

[0092] The basic structure of the robot 1 of the tenth embodiment is the same as that of the first embodiment, and therefore the robot 1 of the tenth embodiment can also enjoy the same effects as those of the first embodiment.

[0093] Furthermore, with the magic hand type telescopic unit 13 (lage tongs) as described above, the height of the upper end of the telescopic unit 13 when the axis A4 and axis A3 are closest to each other as the second arm unit 5 rotates, that is, when the telescopic unit 13 is folded to its smallest size, is kept lower than that of the telescopic unit 13 of the first embodiment. This makes it possible to keep the occupied height of the telescopic unit 13 low during operation.

[0094] [Eleventh embodiment] Fig. 18 is a perspective view of the robot 1 according to the eleventh embodiment, and Fig. 19 is a plan view (partially cross-sectional view) of the robot 1. The robot 1 according to the eleventh embodiment differs from the first embodiment in the following points in terms of the specific configuration of the rotational force transmission unit 6.

[0095] 18 and 19, in the robot 1 of the eleventh embodiment, the first link 14 constituting the extension / contraction unit 13 of the rotational force transmission unit 6 is composed of a first portion 141 connected to the second link 15, a second portion 142 connected to the first base 10 (frame 20), and a connecting unit 16 that connects these together so that they can rotate relative to each other about axis A8. Axis A8 is an axis that extends in the longitudinal direction of the first link 14 and is perpendicular to axes A5 to A7. The connecting unit 16 is composed of a bearing such as a cross roller bearing, and the inner ring of the bearing is fixed to the first portion 141, and the outer ring portion is fixed to the second portion 142.

[0096] According to the robot 1 of the eleventh embodiment, the rotational force generated by the second motor M2 can be transmitted more smoothly to the second arm unit 5 via the rotational force transmission unit 6. That is, if the accuracy of the axes A3 to A7 in the rotational force transmission unit 6 is not sufficiently ensured, unnecessary forces may act on the links 14, 15 and the bearings B5, B13 to B15, causing deformation and creating resistance during operation of the rotational force transmission unit 6. According to the configuration of the eleventh embodiment, relative rotation between the first portion 141 and the second portion 142 is permitted, thereby allowing the unnecessary forces described above to be released. This enables smooth operation of the rotational force transmission unit 6, and as a result, the rotational force generated by the second motor M2 can be transmitted more smoothly to the second arm unit 5.

[0097] 18, the connecting portion 16 is provided on the first link 14 side, but the connecting portion 16 may also be provided on the second link 15 side. Also, although the connecting portion 16 is configured as a bearing, it is not limited to a bearing as long as it can connect the first portion 141 and the second portion 142 so that they can rotate relatively around the axis A8. However, when the connecting portion 16 is configured as a bearing, it becomes possible to easily route the cable 100 inside the telescopic portion 13, as shown in FIG.

[0098] Although not shown in the figures, the tenth embodiment (see FIG. 17) can also employ a configuration similar to that of the eleventh embodiment. In this case, of the link members constituting the plurality of parallel link mechanisms of the extension / contraction section 13, the link member connected to the first base section 10 or the link member connected to the second base section 12 can be provided with a connecting section 16.

[0099] [Twelfth embodiment] Fig. 20 is a perspective view of the robot 1 according to the twelfth embodiment, and Fig. 21 is a plan view (partially cross-sectional view) of the robot 1. Fig. 22 is a cross-sectional view taken along a vertical plane of the robot 1. The robot 1 according to the twelfth embodiment differs from the first embodiment in the following respects in terms of the specific configuration of the rotational force transmission unit 6.

[0100] 20 to 22, in the twelfth embodiment, the extension / contraction unit 13 of the rotational force transmission unit 6 is configured with a linear motion member instead of a link mechanism. Specifically, the extension / contraction unit 13 includes a shaft member 50 connected to the second base portion 12 and a guide member 52 connected to the first base portion 10. In this example, the shaft member 50 is a spline shaft, and the guide member 52 is a cylindrical spline nut.

[0101] The telescopic section 13 has a telescopic structure in which one end (tip side) of the shaft member 50 is inserted into one end (tip side) of the guide member 52. The shaft length L52 of the guide member 52 is set slightly longer than the shaft length L50 of the shaft member 50, and the shaft lengths L50, L52 are set so that in the neutral state of the robot arm 3, the tip of the shaft member 50 is inserted into the tip of the guide member 52 at a position approximately midway between the axis A6 and the axis A7, and that in the state in which the second arm section 5 has rotated the most from the neutral state, the tip of the shaft member 50 is located at the innermost end of the guide member 52 (i.e., does not protrude outside from the guide member 52).

[0102] The other end (base end) of the shaft member 50 is held by a holder member 51, and the shaft member 50 is rotatably connected to the frame 22 (standing portion 22b) of the second base 12 via the holder member 51 around an axis A7. The other end (base end) of the guide member 52 is held by a holder member 53, and the guide member 52 is rotatably connected to the frame 20 (standing portion 20b) of the first base 10 via the holder member 53 around an axis A6. More specifically, as shown in FIG. 21 , a shaft portion 51a provided on the holder member 51 is held by the inner ring of the bearing B15 provided on the standing portion 22b. A shaft portion 53a provided on the holder member 53 is held by the inner ring of the bearing B14 provided on the standing portion 20b. As a result, the shaft member 50 is rotatably connected to the second base portion 12, and the guide member 52 is rotatably connected to the first base portion 10.

[0103] 22, the second motor M2 is oriented upward as in the sixth embodiment (see FIG. 13), and the reducer M2b is fixed to the upper wall 4a of the first arm 4. The output shaft of the reducer M2b is fixed to the frame 20 of the first base 10 of the rotational force transmission unit 6.

[0104] The wiring structure of the cable 100 in the robot 1 of the twelfth embodiment is the same as the wiring structure of the sixth embodiment (see FIG. 13). That is, the cable guide unit 40 is provided on the upper part of the base unit 2. The cable 100 is introduced from the base unit 2 into the cable guide unit 40. Then, the cable 100 is guided through the cable guide unit 40 into the inside of the first arm unit 4, and further guided from the first arm unit 4 to the tip end of the second arm unit 5 through the hollow shaft 5c.

[0105] 23 and 24 are explanatory diagrams of the operation of the robot 1 of the twelfth embodiment, with Fig. 23 being a perspective view and Fig. 24 being a plan view, each showing the operation of the robot 1. Note that in Figs. 23 and 24, the covers 21, 23 of the bases 10, 12 of the rotational force transmission unit 6 and the cable guide unit 40 are omitted.

[0106] 23(a) and 24(a) show the robot 1 with the robot arm 3 in a neutral state. When the second arm unit 5 is driven in the forward direction by the second motor M2 in the robot arm 3 in the neutral state, the second arm unit 5 rotates clockwise (in the direction of arrow R1) in a plan view. At this time, as the rotation angle of the second arm unit 5 increases from the neutral state, the shaft member 50 enters the guide member 52, and the overall length of the extension / contraction unit 13 decreases, as shown in FIGS. 23(b) and 23(c) and 24(b) and 24(c).

[0107] On the other hand, when the second arm unit 5 is reversely driven by the second motor M2, the second arm unit 5 rotates counterclockwise in plan view (in the direction of arrow R2). In this case as well, as the rotation angle of the second arm unit 5 increases from the neutral state, the shaft member 50 enters the guide member 52, reducing the overall length of the extendable unit 13, as shown in Figures 23(d) and 23(e) and 24(d) and 24(e). In other words, the extendable unit 13 extends and contracts in accordance with the rotation of the second arm unit 5 relative to the first arm unit 4.

[0108] Although not shown in the figure, in addition to the rotational driving of the second arm unit 5 by the second motor M2, the first arm unit 4 is also rotationally driven around the axis A1 by the first motor M1, whereby the working axis 7 (end effector) moves horizontally to any position within the movable area Ar shown in Figure 24(a).

[0109] The basic structure of the robot 1 of the twelfth embodiment is the same as that of the first embodiment, and therefore the robot 1 of the twelfth embodiment can also enjoy the same effects as those of the first embodiment. Moreover, in the robot 1 of the twelfth embodiment, the extension / contraction section 13 of the rotational force transmission section 6 is composed of the shaft member 50 and the guide member 52 as described above, so there is no significant change in the height of the extension / contraction section 13 as the second arm section 5 rotates. Therefore, it is possible to keep the occupied height of the extension / contraction section 13 low during operation.

[0110] In this example, the shaft member 50 is a spline shaft, and the guide member 52 is a cylindrical spline nut. However, it is also possible to configure the shaft member 50 as a rail member such as a linear guide, and the guide member 52 as a sliding member such as a slider that slides along the rail member.

[0111] The expansion / contraction section 13 may also have a structure (double row) in which a plurality of rows of sets of shaft members 50 (spline shafts or rail members) and guide members 52 (spline nuts or sliding members) are provided.

[0112] [Thirteenth embodiment] 25 is a schematic perspective view of the robot 1 according to the thirteenth embodiment. (a) in the figure shows the robot 1 with the robot arm 3 in a neutral state. The robot 1 according to the thirteenth embodiment has the same basic configuration as the robot 1 according to the twelfth embodiment, but differs in the configuration of the rotational force transmission unit 6 in the following respects.

[0113] In the thirteenth embodiment, as in the third embodiment (see FIG. 9), the angle formed by the axis A6 with respect to the axis A3 and the angle formed by the axis A7 with respect to the axis A4 are set to the same acute angle. Therefore, the upright portion 20b of the frame 20 in the first base portion 10 and the upright portion 22b of the frame 22 in the second base portion 12 are both provided at an angle relative to the vertical.

[0114] In the configuration of the thirteenth embodiment, as in the twelfth embodiment, when the second arm unit 5 rotates relative to the first arm unit 4, the extension / contraction unit 13 contracts in response to the rotation of the second arm unit 5, as shown in Figures 25(b) and 25(c). Therefore, as in the robot 1 of the twelfth embodiment, the rotational force transmission unit 6 transmits the rotational force of the second motor M2 to the second arm unit 5, and extends and contracts in response to the rotation of the second arm unit 5.

[0115] The basic structure of the robot 1 of the thirteenth embodiment is the same as that of the twelfth embodiment. Therefore, the robot 1 of the thirteenth embodiment can also enjoy the same effects as those of the twelfth embodiment.

[0116] Note that the angle formed by axis A6 with respect to axis A3 and the angle formed by axis A7 with respect to axis A4 are desirably 90° as in the twelfth embodiment from the viewpoint of avoiding interference between the second arm unit 5 and the extension / contraction unit 13. If these angles are smaller than 90°, there is a concern that the second arm unit 5 will interfere with the extension / contraction unit 13. Therefore, in the thirteenth embodiment, the angles are set within a range in which the second arm unit 5 will not interfere with the extension / contraction unit 13, for example, a range of 10° or more and less than 90°. This is the same as in the third embodiment described above.

[0117] [Fourteenth embodiment] Fig. 26 is a cross-sectional view of the robot 1 according to the fourteenth embodiment taken along a vertical plane. Fig. 27 is a perspective view of the robot 1, and (a) in the figure shows the robot 1 with the robot arm 3 in a neutral state. The robot 1 according to the fourteenth embodiment has the same basic configuration as the robot 1 according to the twelfth embodiment (see Figs. 20 to 24), but differs in the configuration of the rotational force transmission unit 6 in the following points.

[0118] In this example, the rotational force transmission section 6 is configured so that the expansion and contraction section 13 is parallel to a plane perpendicular to the axes A2 to A4.

[0119] Specifically, box-shaped frames 20, 22 are provided on the first base 10 and the second base 12, and the base end of the shaft member 50 is fixed to the frame 22 of the second base 12, while the base end of the guide member 52 is fixed to the frame 20 of the first base 10. That is, in the robot 1 of the fourteenth embodiment, the shaft member 50 is restricted from rotating around the axis A7, and the guide member 52 is restricted from rotating around the axis A6.

[0120] In the configuration of this 14th embodiment, as in the 12th embodiment, when the second arm portion 5 rotates from the neutral state of the robot arm 3 shown in Figure 27(a), the shaft member 50 enters the inside of the guide member 52, and the extension / contraction portion 13 contracts, as shown in Figures 27(b) and (c).

[0121] In the fourteenth embodiment, the rotation of the shaft member 50 about the axis A7 and the rotation of the guide member 52 about the axis A6 are both restricted, for the following reasons.

[0122] In a configuration in which the heights of both ends of the extension / contraction unit 13 (i.e., the heights of the axes A6 and A7) are different, as in the twelfth embodiment shown in FIGS. 20 to 24 , a difference occurs between the vertical tilt of the shaft member 50 and the vertical tilt of the guide member 52 as the second arm unit 5 rotates. Therefore, it is necessary to allow the shaft member 50 to rotate about the axis A7 and the guide member 52 to rotate about the axis A6, thereby absorbing the difference in tilt between the shaft member 50 and the guide member 52. On the other hand, in the configuration of the fourteenth embodiment in which the heights of both ends of the extension / contraction unit 13 are equal, no difference in tilt occurs between the shaft member 50 and the guide member 52 even when the second arm unit 5 rotates. Therefore, even if the rotation of the shaft member 50 about the axis A7 and the rotation of the guide member 52 about the axis A6 are both restricted, the operation of the rotational force transmission unit 6 is not impaired.

[0123] The basic structure of the robot 1 of the fourteenth embodiment is the same as that of the twelfth embodiment, and therefore the robot 1 of the fourteenth embodiment can also enjoy the same effects as those of the twelfth embodiment.

[0124] Furthermore, according to the robot 1 of the fourteenth embodiment, when the entire rotational force transmission unit 6 including the extendable unit 13 is disposed inside the width direction of the arm main body (first arm section 4 and second arm section 5) in the neutral state of the robot arm 3, the configuration of the robot arm 3 including the rotational force transmission unit 6 becomes compact. Furthermore, the configuration is simplified because members for rotatably supporting the shaft member 50 and the guide member 52 (the bearings B14, 15 and the holder members 51, 53) are not required.

[0125] [Fifteenth embodiment] 28 is a plan view (partial cross-sectional view) of the robot 1 according to the fifteenth embodiment, showing the robot 1 with the robot arm 3 in a neutral state. The robot 1 according to the fifteenth embodiment has the same basic configuration as the robot 1 according to the twelfth embodiment (see FIGS. 20 to 24), but differs in the configuration of the rotational force transmission unit 6 in the following points.

[0126] 28, in the fifteenth embodiment, the shaft member 50 is rotatably supported by the holder member 51 via the bearing B30 in the extension / contraction section 13. In the fifteenth embodiment, this configuration makes it possible to transmit the rotational force generated by the second motor M2 to the second arm section 5 more smoothly via the rotational force transmission section 6.

[0127] As explained in the eleventh embodiment, if the precision of the axes A3, A4, A6, and A7 in the rotational force transmission unit 6 is not sufficiently ensured, unnecessary forces may act on the shaft member 50, the guide member 52, or the bearings B5, B14, and B15, causing deformation and creating resistance during operation of the rotational force transmission unit 6. According to the configuration of the fifteenth embodiment described above, relative rotation (rotation about the axis) of the shaft member 50 with respect to the holder member 51 is permitted, thereby dissipating unnecessary forces acting on the rotational force transmission unit 6. This enables smooth operation of the rotational force transmission unit 6, and as a result, the rotational force generated by the second motor M2 can be transmitted to the second arm unit 5 more smoothly.

[0128] 28, shaft member 50 is rotatably supported by holder member 51, but guide member 52 may be rotatably supported by holder member 53. In this case, the same effect can be obtained.

[0129] Furthermore, while maintaining the structure in which shaft member 50 is fixed to holder member 51 and guide member 52 is fixed to holder member 53, a configuration may be adopted in which relative rotation between shaft member 50 and guide member 52 is permitted. In this case, smooth operation can be achieved by configuring shaft member 50 as a ball bushing shaft and guide member 52 as a ball bushing nut, for example. With such a configuration, the same effects as the configuration in FIG. 28 can be obtained.

[0130] In the fifteenth embodiment, relative rotation between the shaft member 50 and the guide member 52 is required, making it difficult to arrange the shaft members 50 and the guide members 52 in multiple rows. The configuration in which the shaft member 50 is a ball bushing shaft and the guide member 52 is a ball bushing nut can also be applied to the fourteenth embodiment described above. However, in the fourteenth embodiment, the rotation of the shaft member 50 about the axis A7 is restricted, and the rotation of the guide member 52 about the axis A6 is restricted, so the effect of smoothly transmitting the rotational force generated by the second motor M2 to the second arm portion 5 is low.

[0131] [16th embodiment] 29 is a plan view (partial cross-sectional view) of the robot 1 according to the sixteenth embodiment. The robot 1 according to the sixteenth embodiment has a basic configuration in common with the robot 1 according to the twelfth embodiment (see FIGS. 20 to 24), but differs in the configuration of the rotational force transmission unit 6 in the following points.

[0132] In the 16th embodiment, as shown in Figure 29, the axial length L50 of the shaft member 50 in the telescopic section 13 and the axial length L52 of the guide member 52 are set so that, in the neutral state of the robot arm 3, the tip of the shaft member 50 is inserted (guided) into the guide member 52 only at the position of the first base section 10, i.e., approximately only at the position of the axis A3.

[0133] Although not shown in the figures, in the robot 1 of the 16th embodiment, when the second arm section 5 rotates from the neutral state of the robot arm 3, the shaft member 50 penetrates the guide member 52, and the tip of the shaft member 50 protrudes behind the first arm section 4, i.e., toward the axis A1 (toward the base section 2).

[0134] In the twelfth embodiment (see FIGS. 20 to 24 ), the axial lengths L50, L52 of the shaft member 50 and the guide member 52 are set so that the tip of the shaft member 50 does not protrude from the guide member 52 when the second arm unit 5 rotates while maintaining the inserted state relative to the guide member 52 in the neutral state of the robot arm 3. Therefore, it is conceivable that the axial lengths L50, L52 of the shaft member 50 and the guide member 52 restrict the movable range Ar of the robot arm 3. In contrast, the configuration of the sixteenth embodiment allows the tip of the shaft member 50 to protrude from the guide member 52 when the second arm unit 5 rotates. In other words, the movable range Ar of the robot arm 3 is less likely to be restricted by the axial lengths L50, L52 of the shaft member 50 and the guide member 52. Therefore, the robot 1 of the sixteenth embodiment contributes to an increase in the movable range of the robot arm 3.

[0135] [17th embodiment] 30 is a plan cross-sectional view (partial cross-sectional view) of the robot 1 according to the seventeenth embodiment. The robot 1 according to the seventeenth embodiment has the same basic configuration as the robot 1 according to the twelfth embodiment, but differs in the configuration of the rotational force transmission unit 6 in the following points.

[0136] In the seventeenth embodiment, the guide member 52 constituting the extension / contraction section 13 of the rotational force transmission section 6 is composed of two unit guide members 52a, 52b (referred to as the outer guide member 52a and the inner guide member 52b) that are slidable along the axis of the guide member 52. In other words, the extension / contraction section 13 has a telescopic structure that can be extended and contracted in two stages, with the outer guide member 52a and the inner guide member 52b being slidably arranged concentrically on the shaft member 50. In this example, the shaft member 50 is a splined shaft. The inner guide member 52b is composed of a composite cylindrical body with spline grooves on its inner circumferential surface and splines on its outer circumferential surface, and the outer guide member 52a is composed of a cylindrical spline nut.

[0137] Of the guide member 52, the base end of the outer guide member 52a is fixed to the holder member 53. The telescopic section 13 further includes biasing members that bias the inner guide member 52b from both sides in the axial direction. Specifically, on the second base 12 side, a coil spring 55 is disposed between the holder member 51 and one end of the inner guide member 52b, and on the first base 10 side, a coil spring 56 is disposed between the holder member 53 and the other end of the inner guide member 52b. The coil spring 55 on the second base 12 side is disposed on the outer periphery of the shaft member 50. The coil spring 56 on the first base 10 side is disposed in a spring accommodating recess 531 formed in the holder member 53. With this configuration, the inner guide member 52b is urged toward the first base 10 side relative to the holder member 51 on the second base 12 side by the elastic force of the coil spring 55, and the inner guide member 52b is urged toward the second base 12 side relative to the holder member 53 on the first base 10 side by the elastic force of the coil spring 56.

[0138] According to the robot 1 of the seventeenth embodiment, the telescopic section 13 has a structure that allows it to be extended and retracted in two stages, and therefore the degree of freedom in the extension length of the telescopic section 13 is higher than in the robot 1 of the twelfth embodiment. In other words, when the second arm section 5 rotates, it is possible to further shorten and retract the telescopic section 13. This contributes to expanding the movable range Ar of the robot arm 3.

[0139] Moreover, the inner guide member 52b is biased in opposite directions by the coil springs 55 and 56 from both sides in the axial direction thereof, so that the position of the inner guide member 52b is stably maintained relative to the shaft member 50 and the outer guide member 52a. Therefore, the inner guide member 52b is suppressed or prevented from moving unstably during operation of the robot arm 3.

[0140] In the configuration of Figure 30, the coil spring 56 on the first base portion 10 side corresponds to the "first biasing member" of the present invention, and the coil spring 55 on the second base portion 12 side corresponds to the "second biasing member" of the present invention.

[0141] In the example of Fig. 30, the extension / contraction unit 13 is configured to be extendable in two stages, but as shown in Fig. 31, the extension / contraction unit 13 may be configured to be extendable in three stages. Specifically, the guide member 52 is configured with three unit guide members 52a, 52b, and 52c (referred to as the outer guide member 52a, the first inner guide member 52b, and the second inner guide member 52c) that are slidable along the axis of the guide member. In other words, the extension / contraction unit 13 has the outer guide member 52a, the first inner guide member 52b, and the second inner guide member 52c slidably arranged concentrically on the shaft member 50. In this example, the shaft member 50 is made of a spline shaft, the first and second inner guide members 52b and 52c are made of the composite cylindrical body, and the outer guide member 52a is made of a cylindrical spline nut.

[0142] Furthermore, as biasing members, a coil spring 55a is arranged between the holder member 51 on the second base 12 side and an end of the first inner guide member 52b, and a coil spring 55b having a smaller diameter than the coil spring 55a is arranged between the holder member 51 and an end of the second inner guide member 52c. Furthermore, a coil spring 56a is arranged between the holder member 53 on the first base 10 side and an end of the first inner guide member 52b, and a coil spring 56b having a smaller diameter than the coil spring 56a is arranged between the holder member 53 and an end of the second inner guide member 52c. Of the two coil springs 55a, 55b on the second base 12 side, the smaller diameter coil spring 55b is arranged inside the larger diameter coil spring 55a and on the outer periphery of the shaft member 50, and the larger diameter coil spring 55a is arranged on the outer periphery of the second inner guide member 52c. On the other hand, of the two coil springs 56a, 56b on the first base 10 side, the large diameter coil spring 55a is formed in the holder member 53 and arranged in a first spring accommodating recess 531, and the small diameter coil spring 56b is inside the large diameter coil spring 55a and arranged in a second spring accommodating recess 532 further formed on the inner bottom of the first spring accommodating recess 531.

[0143] 31, it is possible to further increase the degree of freedom in adjusting the extension length of the extension / contraction section 13. In addition, the stepped forces of the coil springs 55a, 55b, 56a, and 56b can stably maintain the positions of the first and second inner guide members 52b and 52c relative to the shaft member 50 and the outer guide member 52a.

[0144] In the configuration of Figure 31, the coil springs 56a, 56b on the first base 10 side each correspond to the "first biasing member" of the present invention, and the coil springs 55a, 55b on the second base 12 side each correspond to the "second biasing member" of the present invention.

[0145] [Eighteenth embodiment] The eighteenth embodiment is an example of application of the present invention to a vertical articulated robot.

[0146] 32 is a perspective view of a vertical articulated robot. The vertical articulated robot 1′ shown in the figure includes a base unit 200 installed on a base stand BP, and a robot arm 300 supported by the base unit 200.

[0147] The robot arm 300 includes a first arm section 210 rotatably connected to the base section 200 around a vertical axis A11, a second arm section 220 having a base end rotatably connected to the first arm section 210 around an axis A12 perpendicular to the axis A11, a third arm section 230 having a base end rotatably connected to the tip section of the second arm section 220 around an axis A13 parallel to the axis A12, a fourth arm section 240 having a base end rotatably connected to the tip section of the third arm section 230 around an axis A14 perpendicular to the axis A13, and a fifth arm section 250 rotatably connected to the fourth arm section 240 around an axis A15 perpendicular to the axis A14. A tool motor M6 is attached to the fifth arm section 250 to generate a rotational force around an axis A16 perpendicular to the axis A15, and an end effector 400, which is a work tool such as a robot hand, is attached to the tool motor M6.

[0148] The first arm portion 210 is driven to rotate about axis A11 by a first arm motor (not shown) arranged on the base portion 200, the second arm portion 220 is driven to rotate about axis A12 by a second arm motor (not shown) arranged within the first arm portion 210, the third arm portion 230 is driven to rotate about axis A13 by a third arm motor (not shown) arranged within the third arm portion 230, the fourth arm portion 240 is driven to rotate about axis A14 by a fourth arm motor (not shown) arranged within the third arm portion 230, and the fifth arm portion 250 is driven to rotate about axis A15 by a fifth arm motor M5 (shown in FIG. 33) arranged within the fourth arm portion 240.

[0149] FIG. 33 is a cross-sectional view of the tip portion of the robot arm 300, specifically, a cross-sectional view of the fourth arm section 240 and the fifth arm section 250. As shown in FIG.

[0150] As shown in the figure, the fourth arm section 240 has an arm support section 241 extending forward at one end side in the width direction (vertical direction in FIG. 33) of its tip section. The fifth arm section 250 is rotatably supported by this arm support section 241. Specifically, a hollow shaft 251 provided on a side wall section of the fifth arm section 250 is held by an inner ring of a bearing B40 provided on the arm support section 241. In this way, the fifth arm section 250 is connected to the fourth arm section 240 so as to be rotatable about axis A15.

[0151] The fifth arm motor M5 that drives the fifth arm section 250 is not located on the axis of the axis A15, i.e., not in the fifth arm section 250, but is located inside the fourth arm section 240, at a position offset from the axis A15 on the opposite side along the axis A14 (a position spaced apart from the base end side of the fourth arm section 240).

[0152] The fifth arm section 250 is rotationally driven about the axis A15 by the rotational force generated by the fifth arm motor M5 being transmitted via the rotational force transmission section 60.

[0153] The configuration of the rotational force transmission unit 60 is substantially the same as the configuration of the rotational force transmission unit 6 already described in the fourteenth embodiment (FIG. 26). That is, the rotational force transmission unit 60 includes a first base portion 110 that rotates about axis A17 by the rotational force of the fifth arm motor M5, a second base portion 120 that is supported on the fifth arm portion 250 via a bearing B42 so as to be rotatable about axis A18, and an extension / contraction unit 130 that connects the first base portion 110 and the second base portion 120 and that deforms (extends and contracts) in response to changes in the distance between the first base portion 110 and the second base portion 120. The axis A17 and the axis A18 are both parallel to the axis A15.

[0154] The telescopic section 130 is made up of a shaft member 150 made of a spline shaft and a guide member 152 made of a spline nut, with the base end of the shaft member 150 being fixed to the second base 120 and the base end of the guide member 152 being fixed to the first base 110. The shaft member 150 and the guide member 152 may be a combination of a ball bushing shaft and a ball bushing nut, or may be a combination of a rail member such as a linear guide and a sliding member such as a linear guide slider.

[0155] That is, when the fifth arm motor M5 is driven, its rotational force is transmitted to the fifth arm section 250 via the rotational force transmission section 60. This causes the fifth arm section 250 to rotate about the axis A15 relative to the fourth arm section 240. At this time, when the fifth arm section 250 rotates, the extension / contraction section 13 extends and contracts accordingly.

[0156] According to the configuration of this robot 1', the fifth arm motor M5 that drives the fifth arm section 250 is not disposed in the fifth arm section 250, but is disposed inside the fourth arm section 240 at a position shifted on the opposite side along the axis A14 from the axis A15. This achieves a reduction in the weight of the fifth arm section 250, and reduces the inertia (moment of inertia) of the fifth arm section 250 about the axis A15. Furthermore, the fifth arm section 250 can be made more compact.

[0157] In the eighteenth embodiment, the fourth arm section 240 corresponds to the "first arm section" of the present invention (claim 17), and the fifth arm section 250 corresponds to the "second arm section." Also, the axis A15 corresponds to the "first axis" of the present invention, the axis A17 corresponds to the "second axis," and the axis A18 corresponds to the "third axis." Also, the fifth-arm motor M5 corresponds to the "motor" of the present invention.

[0158] While the articulated robots according to the first to eighteenth embodiments of the present invention have been described above, the articulated robots according to the embodiments are merely examples of preferred embodiments of the present invention, and their specific configurations can be modified without departing from the spirit of the present invention. In particular, configurations that appropriately combine the characteristic configurations disclosed in the first to eighteenth embodiments are within the scope of the present invention.

[0159] The present invention can be summarized as follows.

[0160] The articulated robot of the present invention is a articulated robot equipped with an arm including a first arm portion rotatable about a first axis, and a second arm portion connected to the first arm portion so as to be rotatable about a second axis parallel to the first axis, and is equipped with a first motor that generates a rotational force to rotate the first arm portion about the first axis, a second motor that is positioned at a position on the first arm portion closer to the first axis than the second axis, and generates a rotational force to rotate the second arm portion, and a rotational force transmission portion that connects the first arm portion and the second arm portion, transmits the rotational force generated by the second motor to the second arm portion, and deforms in response to the rotation of the second arm portion relative to the first arm portion.

[0161] With this configuration of the articulated robot, the second motor for driving the second arm is disposed closer to the first axis than the second axis of the first arm, thereby making it possible to reduce the inertia (moment of inertia) of the arm around the first axis compared to conventional articulated robots in which the second motor is disposed on the second axis. Also, with respect to the second arm, the inertia based on the position of the second motor can be reduced compared to when the second motor is disposed on the second axis. Therefore, with this configuration of the articulated robot, it is possible to effectively reduce the inertia around the rotation axis of the arm of the articulated robot.

[0162] In the above-mentioned articulated robot, the second motor generates a rotational force around a third axis parallel to the first axis and the second axis, and the rotational force transmission unit includes a first base that rotates around the third axis by the rotational force of the second motor, a second base that is supported by the second arm unit so as to be rotatable around a fourth axis parallel to the third axis, and an extension / contraction unit that connects the first base and the second base and extends and contracts in response to changes in the distance between the first base and the second base due to the rotation of the second arm unit relative to the first arm unit.

[0163] According to this configuration, the rotational force of the second motor can be transmitted to the second arm portion via the rotational force transmission portion, and the second arm portion can be smoothly rotated relative to the first arm portion.

[0164] In this case, it is preferable that the extension / contraction unit is made up of a link mechanism. With this configuration, it is possible to transmit the rotational force of the second motor to the second arm unit with a relatively simple structure, and to smoothly deform (extend / contract) the rotational force transmission unit in accordance with the rotation of the second arm unit.

[0165] More specifically, the link mechanism includes a first link and a second link whose ends on one side are rotatably connected to each other about a fifth axis that forms a predetermined angle with the first axis, the other end of the first link is rotatably connected to the first base about an axis parallel to the fifth axis, and the other end of the second link is rotatably connected to the second base about an axis parallel to the fifth axis. In this case, it is preferable that the predetermined angle is 90°.

[0166] With this configuration, it is possible to transmit the rotational force of the second motor to the second motor via the rotational force transmission section while avoiding interference between the first arm section, the second arm section and the rotational force transmission section.

[0167] Furthermore, in the above-mentioned articulated robot, when the telescopic section is a link mechanism, the link mechanism may be a magic hand-type link mechanism in which one end is rotatably connected to the first base section about an axis perpendicular to the third axis, and the other end is rotatably connected to the second base section about an axis perpendicular to the fourth axis.

[0168] This configuration is advantageous in keeping the height occupied by the link mechanism low when the link mechanism is folded in accordance with the rotation of the second arm portion.

[0169] Furthermore, in the above-mentioned articulated robot, one of the multiple links constituting the link mechanism may be configured to include a first part and a second part separated from each other in the longitudinal direction of the link, and a connecting portion that connects the first part and the second part so that they can rotate relative to each other around an axis extending in the longitudinal direction of the link.

[0170] This configuration allows the rotational force of the second motor to be transmitted more smoothly to the second arm portion via the rotational force transmission unit. In other words, if the precision of the rotational force transmission unit is not sufficiently ensured, unnecessary forces may act on each link, causing deformation and creating resistance during operation of the rotational force transmission unit. The above configuration allows relative rotation between the first and second portions, thereby dissipating the unnecessary forces described above. This enables smooth operation of the rotational force transmission unit, and as a result, the rotational force generated by the second motor can be transmitted more smoothly to the second arm portion.

[0171] Furthermore, in the above-mentioned articulated robot, if a cable is arranged to extend from the base portion to the second arm portion, at least a portion of the cable may be arranged through the interior of the rotational force transmission portion.

[0172] According to this configuration, a rational configuration is achieved in which the interior of the rotational force transmission section is utilized as a space for routing cables.

[0173] In addition, in the above-mentioned articulated robot, the extension / contraction section may be configured to include an axial member supported on one side of the first base section and the second base section, and a guide member supported on the other side to hold the axial member slidably in its axial direction.

[0174] In this configuration as well, it is possible to transmit the rotational force of the second motor to the second arm portion while smoothly deforming (expanding and contracting) the rotational force transmission portion in accordance with the rotation of the second arm portion, with a relatively simple configuration.

[0175] More specifically, the shaft member is supported on one of the first and second bases so as to be rotatable about a sixth axis that forms a predetermined angle with the first axis, and the holder member is supported on the other of the first and second bases so as to be rotatable about an axis that is parallel to the sixth axis. In this case, it is preferable that the predetermined angle is 90°.

[0176] With this configuration, it is possible to transmit the rotational force of the second motor to the second motor via the rotational force transmission section while avoiding interference between the first arm section, the second arm section and the rotational force transmission section.

[0177] When the extension / contraction section includes the shaft member and the guide member, it is preferable that the extension / contraction section be provided parallel to a plane perpendicular to the second axis and the third axis.

[0178] According to this configuration, the rotational force transmission part can be smoothly deformed (expanded and contracted) in accordance with the rotation of the second arm part, without rotatably supporting the shaft member and the guide member relative to the first base part and the second base part.

[0179] In the articulated robot, one side of the shaft member and the guide member may be rotatably mounted on the first base or the second base supporting the one side, and the shaft member may be rotatably mounted on the guide member.

[0180] This configuration allows the rotational force of the second motor to be transmitted more smoothly to the second arm portion via the rotational force transmission unit. In other words, if the precision of the rotational force transmission unit is not sufficiently ensured, unnecessary forces may act on the shaft member or guide member, causing deformation and creating resistance during operation of the rotational force transmission unit. The above configuration allows the aforementioned unnecessary forces to be released, enabling smooth operation of the rotational force transmission unit, and as a result, allowing the rotational force generated by the second motor to be transmitted more smoothly to the second arm portion.

[0181] In the above articulated robot, the guide member may be made up of a plurality of unit guide members of a telescopic structure arranged concentrically on the shaft member so as to be slidable relative to one another.

[0182] With this configuration, the extension / contraction section can be extended and contracted in multiple stages, increasing the degree of freedom in the extension / contraction length of the extension / contraction section. In other words, it is possible to shorten and contract the extension / contraction section when the second arm section rotates. This contributes to expanding the range of motion of the arm.

[0183] In this case, when the outermost unit guide member among the plurality of unit guide members is defined as an outer guide member and the unit guide member arranged inside the outer unit guide member is defined as an inner guide member, the outer guide member may be connected to the base on the other side, and the extension / contraction portion may include biasing members arranged on both sides of the inner guide member in the axial direction, and may include a first biasing member that biases the inner guide member toward the base on one side relative to the base on the other side, and a second biasing member that biases the inner guide member toward the base on the other side relative to the base on one side.

[0184] According to this configuration, the position of the inner guide member is stably maintained relative to the shaft member and the outer guide member, which suppresses or prevents the inner guide member from moving unstably during operation of the robot arm 3.

[0185] Another aspect of the present invention provides a multi-joint robot having an arm including a first arm portion and a second arm portion rotatably connected to the first arm portion about a first axis, the multi-joint robot including: a motor disposed at a position spaced apart from the first axis of the first arm portion toward the base end of the first arm portion, the motor generating a rotational force to rotate the second arm portion; and a rotational force transmission unit connecting the first arm portion and the second arm portion and transmitting the rotational force generated by the motor to the second arm portion, the motor generating a rotational force about a second axis parallel to the first axis, the rotational force transmission unit including: a first base portion that rotates about the second axis by the rotational force of the second motor; a second base portion supported by the second arm portion rotatably about a third axis parallel to the second axis; and an extension / contraction unit connecting the first base portion and the second base portion and extending / contracting in response to a change in the distance between the first base portion and the second base portion due to the rotation of the second arm portion relative to the first arm portion.

[0186] With this configuration of the articulated robot, the inertia (moment of inertia) of the second arm section when the position of the second motor is used as the reference can be effectively reduced compared to when the second motor is positioned on the second axis.

Claims

1. A multi-joint robot having an arm including a first arm portion rotatable about a first axis, and a second arm portion rotatably connected to the first arm portion about a second axis parallel to the first axis, a first motor that generates a rotational force that rotates the first arm portion about the first axis; a second motor disposed at a position closer to the first axis than the second axis in the first arm portion, the second motor generating a rotational force that rotates the second arm portion; a rotational force transmission unit that connects the first arm unit and the second arm unit to transmit a rotational force generated by the second motor to the second arm unit and that deforms in accordance with the rotation of the second arm unit relative to the first arm unit, the second motor generates a rotational force about a third axis parallel to the first axis and the second axis, The rotational force transmission unit is a first base portion that rotates about the third axis by a rotational force of the second motor; a second base portion supported by the second arm portion so as to be rotatable about a fourth axis line parallel to the third axis line; an extension / contraction unit that connects the first base unit and the second base unit and that extends and contracts in response to a change in the distance between the first base unit and the second base unit due to rotation of the second arm unit relative to the first arm unit, The expansion / contraction unit is made up of a link mechanism, the link mechanism includes a first link member and a second link member whose ends on one side are rotatably connected to each other about a fifth axis that forms a predetermined angle with the first axis, the other end of the first link member is rotatably connected to the first base portion around an axis parallel to the fifth axis, an end portion on the other side of the second link member is rotatably connected to the second base portion around an axis parallel to the fifth axis,

2. The articulated robot according to claim 1, The articulated robot is characterized in that the predetermined angle is 90°.

3. The articulated robot according to claim 1 or 2, a connecting portion that connects the first portion and the second portion so as to be rotatable relative to each other around an axis extending in the longitudinal direction of the link;

4. A multi-joint robot having an arm including a first arm portion rotatable about a first axis, and a second arm portion rotatably connected to the first arm portion about a second axis parallel to the first axis, a first motor that generates a rotational force that rotates the first arm portion about the first axis; a second motor disposed at a position closer to the first axis than the second axis in the first arm portion, the second motor generating a rotational force that rotates the second arm portion; a rotational force transmission unit that connects the first arm unit and the second arm unit to transmit a rotational force generated by the second motor to the second arm unit and that deforms in accordance with the rotation of the second arm unit relative to the first arm unit, the second motor generates a rotational force about a third axis parallel to the first axis and the second axis, The rotational force transmission unit is a first base portion that rotates about the third axis by a rotational force of the second motor; a second base portion supported by the second arm portion so as to be rotatable about a fourth axis line parallel to the third axis line; an extension / contraction unit that connects the first base unit and the second base unit and that extends and contracts in response to a change in the distance between the first base unit and the second base unit due to rotation of the second arm unit relative to the first arm unit, the telescopic section comprises a magic hand-type link mechanism, one end of which is rotatably connected to the first base section about an axis perpendicular to the third axis, and the other end of which is rotatably connected to the second base section about an axis perpendicular to the fourth axis.

5. A multi-joint robot having an arm including a base portion, a first arm portion rotatable about a first axis relative to the base portion, and a second arm portion rotatably connected to the first arm portion about a second axis parallel to the first axis, a first motor that generates a rotational force that rotates the first arm portion about the first axis; a second motor disposed at a position closer to the first axis than the second axis in the first arm portion, the second motor generating a rotational force that rotates the second arm portion; a rotational force transmission section that connects the first arm section and the second arm section to transmit a rotational force generated by the second motor to the second arm section and that deforms in response to rotation of the second arm section relative to the first arm section; a cable routed from the base portion to the second arm portion, The articulated robot is characterized in that at least a portion of the cable is routed through the inside of the rotational force transmission unit.

6. A multi-joint robot having an arm including a first arm portion rotatable about a first axis, and a second arm portion rotatably connected to the first arm portion about a second axis parallel to the first axis, a first motor that generates a rotational force that rotates the first arm portion about the first axis; a second motor disposed at a position closer to the first axis than the second axis in the first arm portion, the second motor generating a rotational force that rotates the second arm portion; a rotational force transmission unit that connects the first arm unit and the second arm unit to transmit a rotational force generated by the second motor to the second arm unit and that deforms in accordance with the rotation of the second arm unit relative to the first arm unit, the second motor generates a rotational force about a third axis parallel to the first axis and the second axis, The rotational force transmission unit is a first base portion that rotates about the third axis by a rotational force of the second motor; a second base portion supported by the second arm portion so as to be rotatable about a fourth axis line parallel to the third axis line; an extension / contraction unit that connects the first base unit and the second base unit and that extends and contracts in response to a change in the distance between the first base unit and the second base unit due to rotation of the second arm unit relative to the first arm unit, A multi-joint robot characterized in that the extension / contraction section comprises an axis member supported on one side of the first base section and the second base section, and a guide member supported on the other side and holding the axis member slidably in its axial direction.

7. The articulated robot according to claim 6, the shaft member is supported rotatably about a sixth axis that forms a predetermined angle with the first axis relative to the one of the first base portion and the second base portion, The articulated robot, wherein the guide member is supported rotatably about an axis parallel to the sixth axis relative to the other of the first base portion and the second base portion.

8. The articulated robot according to claim 7, The articulated robot is characterized in that the predetermined angle is 90°.

9. The articulated robot according to claim 6, An articulated robot, characterized in that the extension and contraction section is provided parallel to a plane perpendicular to the second axis and the third axis.

10. The articulated robot according to any one of claims 6 to 9, A multi-joint robot, characterized in that one side of the shaft member and the guide member is rotatably mounted around an axis relative to the first base or the second base that supports that side.

11. 10. The articulated robot according to claim 6, wherein the shaft member is provided so as to be rotatable relative to the guide member.

12. The articulated robot according to any one of claims 6 to 9, The articulated robot is characterized in that the guide member is made up of a plurality of unit guide members with a telescopic structure that are arranged concentrically on the shaft member and can slide relative to each other.

13. The articulated robot according to claim 12, When the outermost unit guide member among the plurality of unit guide members is defined as an outer guide member and the unit guide member disposed inside the outer unit guide member is defined as an inner guide member, The outer guide member is connected to the other base portion, a first biasing member that biases the inner guide member toward the base on one side relative to the base on the other side, and a second biasing member that biases the inner guide member toward the base on the one side relative to the base on the other side.

14. A horizontal articulated robot having an arm including a first arm portion and a second arm portion rotatably connected to the first arm portion about a first axis line extending vertically, a motor disposed at a position spaced apart from the first axis of the first arm portion toward a base end of the first arm portion, the motor generating a rotational force that rotates the second arm portion; a rotational force transmission unit that connects the first arm unit and the second arm unit and transmits the rotational force generated by the motor to the second arm unit, the motor generates a rotational force about a second axis parallel to the first axis, The rotational force transmission unit is a first base portion supported by the first arm portion and rotated about the second axis by a rotational force of the motor; a second base portion supported by the second arm portion so as to be rotatable about a third axis parallel to the second axis; an extension / contraction unit that connects the first base unit and the second base unit and rotates integrally with the first base unit and the second base unit about the second axis, and that extends and contracts in response to a change in the distance between the first base unit and the second base unit due to the rotation of the second arm unit relative to the first arm unit.

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